diff --git a/.gitattributes b/.gitattributes
index b223c8ac5fb84..f0b1c67bd0fdd 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -9,3 +9,7 @@ src/etc/installer/gfx/* binary
 *.woff binary
 src/vendor/** -text
 Cargo.lock -merge linguist-generated=false
+
+# Older git versions try to fix line endings on images, this prevents it.
+*.png binary
+*.ico binary
diff --git a/.gitmodules b/.gitmodules
index c4763612dbf3c..b75e312dedf73 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,7 +1,3 @@
-[submodule "src/llvm"]
-	path = src/llvm
-	url = https://github.com/rust-lang/llvm.git
-	branch = master
 [submodule "src/rust-installer"]
 	path = src/tools/rust-installer
 	url = https://github.com/rust-lang/rust-installer.git
@@ -28,7 +24,7 @@
 	url = https://github.com/rust-lang-nursery/rustfmt.git
 [submodule "src/tools/miri"]
 	path = src/tools/miri
-	url = https://github.com/solson/miri.git
+	url = https://github.com/rust-lang/miri.git
 [submodule "src/doc/rust-by-example"]
 	path = src/doc/rust-by-example
 	url = https://github.com/rust-lang/rust-by-example.git
@@ -38,20 +34,16 @@
 [submodule "src/stdsimd"]
 	path = src/stdsimd
 	url = https://github.com/rust-lang-nursery/stdsimd.git
-[submodule "src/tools/lld"]
-	path = src/tools/lld
-	url = https://github.com/rust-lang/lld.git
-[submodule "src/tools/lldb"]
-	path = src/tools/lldb
-	url = https://github.com/rust-lang-nursery/lldb.git
-	branch = rust-release-80-v2
-[submodule "src/tools/clang"]
-	path = src/tools/clang
-	url = https://github.com/rust-lang-nursery/clang.git
-	branch = rust-release-80-v2
 [submodule "src/doc/rustc-guide"]
 	path = src/doc/rustc-guide
 	url = https://github.com/rust-lang/rustc-guide.git
 [submodule "src/doc/edition-guide"]
 	path = src/doc/edition-guide
-	url = https://github.com/rust-lang-nursery/edition-guide
+	url = https://github.com/rust-lang-nursery/edition-guide.git
+[submodule "src/llvm-project"]
+	path = src/llvm-project
+	url = https://github.com/rust-lang/llvm-project.git
+	branch = rustc/8.0-2019-01-16
+[submodule "src/doc/embedded-book"]
+	path = src/doc/embedded-book
+	url = https://github.com/rust-embedded/book.git
diff --git a/.mailmap b/.mailmap
index a928606b693e5..d265f45c5cafa 100644
--- a/.mailmap
+++ b/.mailmap
@@ -155,6 +155,7 @@ Matt Brubeck <mbrubeck@limpet.net> <mbrubeck@cs.hmc.edu>
 Matthew Auld <matthew.auld@intel.com>
 Matthew McPherrin <matthew@mcpherrin.ca> <matt@mcpherrin.ca>
 Matthijs Hofstra <thiezz@gmail.com>
+Melody Horn <melody@boringcactus.com> <mathphreak@gmail.com>
 Michael Williams <m.t.williams@live.com>
 Michael Woerister <michaelwoerister@posteo> <michaelwoerister@gmail>
 Mickaël Raybaud-Roig <raybaudroigm@gmail.com> m-r-r <raybaudroigm@gmail.com>
diff --git a/.travis.yml b/.travis.yml
index c4efa88460325..7985b6c0e191f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -168,7 +168,7 @@ matrix:
       if: branch = auto
     - env: IMAGE=i686-gnu-nopt
       if: branch = auto
-    - env: IMAGE=wasm32-unknown
+    - env: IMAGE=test-various
       if: branch = auto
     - env: IMAGE=x86_64-gnu
       if: branch = auto
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 65cdfe67b5b08..e785f03d7de2b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -19,9 +19,16 @@ hop on [#rust-internals][pound-rust-internals].
 
 As a reminder, all contributors are expected to follow our [Code of Conduct][coc].
 
+The [rustc-guide] is your friend! It describes how the compiler works and how
+to contribute to it in more detail than this document.
+
+If this is your first time contributing, the [walkthrough] chapter of the guide
+can give you a good example of how a typical contribution would go.
+
 [pound-rust-internals]: https://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-internals
 [internals]: https://internals.rust-lang.org
 [coc]: https://www.rust-lang.org/conduct.html
+[walkthrough]: https://rust-lang.github.io/rustc-guide/walkthrough.html
 
 ## Feature Requests
 [feature-requests]: #feature-requests
@@ -89,222 +96,14 @@ $ RUST_BACKTRACE=1 rustc ...
 ```
 
 ## The Build System
-[the-build-system]: #the-build-system
-
-Rust's build system allows you to bootstrap the compiler, run tests &
-benchmarks, generate documentation, install a fresh build of Rust, and more.
-It's your best friend when working on Rust, allowing you to compile & test
-your contributions before submission.
-
-The build system lives in [the `src/bootstrap` directory][bootstrap] in the
-project root. Our build system is itself written in Rust and is based on Cargo
-to actually build all the compiler's crates. If you have questions on the build
-system internals, try asking in [`#rust-internals`][pound-rust-internals].
-
-[bootstrap]: https://github.com/rust-lang/rust/tree/master/src/bootstrap/
-
-### Configuration
-[configuration]: #configuration
-
-Before you can start building the compiler you need to configure the build for
-your system. In most cases, that will just mean using the defaults provided
-for Rust.
-
-To change configuration, you must copy the file `config.toml.example`
-to `config.toml` in the directory from which you will be running the build, and
-change the settings provided.
-
-There are large number of options provided in this config file that will alter the
-configuration used in the build process. Some options to note:
-
-#### `[llvm]`:
-- `assertions = true` = This enables LLVM assertions, which makes LLVM misuse cause an assertion failure instead of weird misbehavior. This also slows down the compiler's runtime by ~20%.
-- `ccache = true` - Use ccache when building llvm
-
-#### `[build]`:
-- `compiler-docs = true` - Build compiler documentation
-
-#### `[rust]`:
-- `debuginfo = true` - Build a compiler with debuginfo. Makes building rustc slower, but then you can use a debugger to debug `rustc`.
-- `debuginfo-lines = true` - An alternative to `debuginfo = true` that doesn't let you use a debugger, but doesn't make building rustc slower and still gives you line numbers in backtraces.
-- `debuginfo-tools = true` - Build the extended tools with debuginfo.
-- `debug-assertions = true` - Makes the log output of `debug!` work.
-- `optimize = false` - Disable optimizations to speed up compilation of stage1 rust, but makes the stage1 compiler x100 slower.
-
-For more options, the `config.toml` file contains commented out defaults, with
-descriptions of what each option will do.
-
-Note: Previously the `./configure` script was used to configure this
-project. It can still be used, but it's recommended to use a `config.toml`
-file. If you still have a `config.mk` file in your directory - from
-`./configure` - you may need to delete it for `config.toml` to work.
-
-### Building
-[building]: #building
-
-A default configuration requires around 3.5 GB of disk space, whereas building a debug configuration may require more than 30 GB.
 
-Dependencies
-- [build dependencies](README.md#building-from-source)
-- `gdb` 6.2.0 minimum, 7.1 or later recommended for test builds
+For info on how to configure and build the compiler, please see [this
+chapter][rustcguidebuild] of the rustc-guide. This chapter contains info for
+contributions to the compiler and the standard library. It also lists some
+really useful commands to the build system (`./x.py`), which could save you a
+lot of time.
 
-The build system uses the `x.py` script to control the build process. This script
-is used to build, test, and document various parts of the compiler. You can
-execute it as:
-
-```sh
-python x.py build
-```
-
-On some systems you can also use the shorter version:
-
-```sh
-./x.py build
-```
-
-To learn more about the driver and top-level targets, you can execute:
-
-```sh
-python x.py --help
-```
-
-The general format for the driver script is:
-
-```sh
-python x.py <command> [<directory>]
-```
-
-Some example commands are `build`, `test`, and `doc`. These will build, test,
-and document the specified directory. The second argument, `<directory>`, is
-optional and defaults to working over the entire compiler. If specified,
-however, only that specific directory will be built. For example:
-
-```sh
-# build the entire compiler
-python x.py build
-
-# build all documentation
-python x.py doc
-
-# run all test suites
-python x.py test
-
-# build only the standard library
-python x.py build src/libstd
-
-# test only one particular test suite
-python x.py test src/test/rustdoc
-
-# build only the stage0 libcore library
-python x.py build src/libcore --stage 0
-```
-
-You can explore the build system through the various `--help` pages for each
-subcommand. For example to learn more about a command you can run:
-
-```
-python x.py build --help
-```
-
-To learn about all possible rules you can execute, run:
-
-```
-python x.py build --help --verbose
-```
-
-Note: Previously `./configure` and `make` were used to build this project.
-They are still available, but `x.py` is the recommended build system.
-
-### Useful commands
-[useful-commands]: #useful-commands
-
-Some common invocations of `x.py` are:
-
-- `x.py build --help` - show the help message and explain the subcommand
-- `x.py build src/libtest --stage 1` - build up to (and including) the first
-  stage. For most cases we don't need to build the stage2 compiler, so we can
-  save time by not building it. The stage1 compiler is a fully functioning
-  compiler and (probably) will be enough to determine if your change works as
-  expected.
-- `x.py build src/rustc --stage 1` - This will build just rustc, without libstd.
-  This is the fastest way to recompile after you changed only rustc source code.
-  Note however that the resulting rustc binary won't have a stdlib to link
-  against by default. You can build libstd once with `x.py build src/libstd`,
-  but it is only guaranteed to work if recompiled, so if there are any issues
-  recompile it.
-- `x.py test` - build the full compiler & run all tests (takes a while). This
-  is what gets run by the continuous integration system against your pull
-  request. You should run this before submitting to make sure your tests pass
-  & everything builds in the correct manner.
-- `x.py test src/libstd --stage 1` - test the standard library without
-  recompiling stage 2.
-- `x.py test src/test/run-pass --test-args TESTNAME` - Run a matching set of
-  tests.
-  - `TESTNAME` should be a substring of the tests to match against e.g. it could
-    be the fully qualified test name, or just a part of it.
-    `TESTNAME=collections::hash::map::test_map::test_capacity_not_less_than_len`
-    or `TESTNAME=test_capacity_not_less_than_len`.
-- `x.py test src/test/run-pass --stage 1 --test-args <substring-of-test-name>` -
-  Run a single rpass test with the stage1 compiler (this will be quicker than
-  running the command above as we only build the stage1 compiler, not the entire
-  thing).  You can also leave off the directory argument to run all stage1 test
-  types.
-- `x.py test src/libcore --stage 1` - Run stage1 tests in `libcore`.
-- `x.py test src/tools/tidy` - Check that the source code is in compliance with
-  Rust's style guidelines. There is no official document describing Rust's full
-  guidelines as of yet, but basic rules like 4 spaces for indentation and no
-  more than 99 characters in a single line should be kept in mind when writing
-  code.
-
-### Using your local build
-[using-local-build]: #using-local-build
-
-If you use Rustup to manage your rust install, it has a feature called ["custom
-toolchains"][toolchain-link] that you can use to access your newly-built compiler
-without having to install it to your system or user PATH. If you've run `python
-x.py build`, then you can add your custom rustc to a new toolchain like this:
-
-[toolchain-link]: https://github.com/rust-lang-nursery/rustup.rs#working-with-custom-toolchains-and-local-builds
-
-```
-rustup toolchain link <name> build/<host-triple>/stage2
-```
-
-Where `<host-triple>` is the build triple for the host (the triple of your
-computer, by default), and `<name>` is the name for your custom toolchain. (If you
-added `--stage 1` to your build command, the compiler will be in the `stage1`
-folder instead.) You'll only need to do this once - it will automatically point
-to the latest build you've done.
-
-Once this is set up, you can use your custom toolchain just like any other. For
-example, if you've named your toolchain `local`, running `cargo +local build` will
-compile a project with your custom rustc, setting `rustup override set local` will
-override the toolchain for your current directory, and `cargo +local doc` will use
-your custom rustc and rustdoc to generate docs. (If you do this with a `--stage 1`
-build, you'll need to build rustdoc specially, since it's not normally built in
-stage 1. `python x.py build --stage 1 src/libstd src/tools/rustdoc` will build
-rustdoc and libstd, which will allow rustdoc to be run with that toolchain.)
-
-### Out-of-tree builds
-[out-of-tree-builds]: #out-of-tree-builds
-
-Rust's `x.py` script fully supports out-of-tree builds - it looks for
-the Rust source code from the directory `x.py` was found in, but it
-reads the `config.toml` configuration file from the directory it's
-run in, and places all build artifacts within a subdirectory named `build`.
-
-This means that if you want to do an out-of-tree build, you can just do it:
-```
-$ cd my/build/dir
-$ cp ~/my-config.toml config.toml # Or fill in config.toml otherwise
-$ path/to/rust/x.py build
-...
-$ # This will use the Rust source code in `path/to/rust`, but build
-$ # artifacts will now be in ./build
-```
-
-It's absolutely fine to have multiple build directories with different
-`config.toml` configurations using the same code.
+[rustcguidebuild]: https://rust-lang.github.io/rustc-guide/how-to-build-and-run.html
 
 ## Pull Requests
 [pull-requests]: #pull-requests
@@ -320,26 +119,13 @@ bring those changes into the source repository.
 
 Please make pull requests against the `master` branch.
 
-Compiling all of `./x.py test` can take a while. When testing your pull request,
-consider using one of the more specialized `./x.py` targets to cut down on the
-amount of time you have to wait. You need to have built the compiler at least
-once before running these will work, but that’s only one full build rather than
-one each time.
-
-    $ python x.py test --stage 1
-
-is one such example, which builds just `rustc`, and then runs the tests. If
-you’re adding something to the standard library, try
-
-    $ python x.py test src/libstd --stage 1
-
 Please make sure your pull request is in compliance with Rust's style
 guidelines by running
 
     $ python x.py test src/tools/tidy
 
 Make this check before every pull request (and every new commit in a pull
-request) ; you can add [git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)
+request); you can add [git hooks](https://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks)
 before every push to make sure you never forget to make this check.
 
 All pull requests are reviewed by another person. We have a bot,
@@ -375,10 +161,10 @@ it can be found [here][rctd].
 
 Currently building Rust will also build the following external projects:
 
-* [clippy](https://github.com/rust-lang-nursery/rust-clippy)
-* [miri](https://github.com/solson/miri)
-* [rustfmt](https://github.com/rust-lang-nursery/rustfmt)
-* [rls](https://github.com/rust-lang-nursery/rls/)
+* [clippy](https://github.com/rust-lang/rust-clippy)
+* [miri](https://github.com/rust-lang/miri)
+* [rustfmt](https://github.com/rust-lang/rustfmt)
+* [rls](https://github.com/rust-lang/rls/)
 
 We allow breakage of these tools in the nightly channel. Maintainers of these
 projects will be notified of the breakages and should fix them as soon as
@@ -405,9 +191,9 @@ before the PR is merged.
 
 Rust's build system builds a number of tools that make use of the
 internals of the compiler. This includes 
-[Clippy](https://github.com/rust-lang-nursery/rust-clippy),
-[RLS](https://github.com/rust-lang-nursery/rls) and
-[rustfmt](https://github.com/rust-lang-nursery/rustfmt). If these tools
+[Clippy](https://github.com/rust-lang/rust-clippy),
+[RLS](https://github.com/rust-lang/rls) and
+[rustfmt](https://github.com/rust-lang/rustfmt). If these tools
 break because of your changes, you may run into a sort of "chicken and egg"
 problem. These tools rely on the latest compiler to be built so you can't update
 them to reflect your changes to the compiler until those changes are merged into
@@ -467,10 +253,10 @@ to complete a few more steps which are outlined with their rationale below.
 
 *(This error may change in the future to include more information.)*
 ```
-error: failed to resolve patches for `https://github.com/rust-lang-nursery/rustfmt`
+error: failed to resolve patches for `https://github.com/rust-lang/rustfmt`
 
 Caused by:
-  patch for `rustfmt-nightly` in `https://github.com/rust-lang-nursery/rustfmt` did not resolve to any crates
+  patch for `rustfmt-nightly` in `https://github.com/rust-lang/rustfmt` did not resolve to any crates
 failed to run: ~/rust/build/x86_64-unknown-linux-gnu/stage0/bin/cargo build --manifest-path ~/rust/src/bootstrap/Cargo.toml
 ```
 
@@ -532,6 +318,12 @@ to check small fixes. For example, `rustdoc src/doc/reference.md` will render
 reference to `doc/reference.html`. The CSS might be messed up, but you can
 verify that the HTML is right.
 
+Additionally, contributions to the [rustc-guide] are always welcome. Contributions
+can be made directly at [the
+rust-lang/rustc-guide](https://github.com/rust-lang/rustc-guide) repo. The issue
+tracker in that repo is also a great way to find things that need doing. There
+are issues for beginners and advanced compiler devs alike!
+
 ## Issue Triage
 [issue-triage]: #issue-triage
 
@@ -627,7 +419,7 @@ For people new to Rust, and just starting to contribute, or even for
 more seasoned developers, some useful places to look for information
 are:
 
-* The [rustc guide] contains information about how various parts of the compiler work
+* The [rustc guide] contains information about how various parts of the compiler work and how to contribute to the compiler
 * [Rust Forge][rustforge] contains additional documentation, including write-ups of how to achieve common tasks
 * The [Rust Internals forum][rif], a place to ask questions and
   discuss Rust's internals
diff --git a/COPYRIGHT b/COPYRIGHT
index 6596c5a3d9aff..dc9abf84b8e5a 100644
--- a/COPYRIGHT
+++ b/COPYRIGHT
@@ -23,7 +23,7 @@ The Rust Project includes packages written by third parties.
 The following third party packages are included, and carry
 their own copyright notices and license terms:
 
-* LLVM. Code for this package is found in src/llvm.
+* LLVM. Code for this package is found in src/llvm-project.
 
     Copyright (c) 2003-2013 University of Illinois at
     Urbana-Champaign.  All rights reserved.
@@ -73,8 +73,8 @@ their own copyright notices and license terms:
     OTHER DEALINGS WITH THE SOFTWARE.
 
 * Additional libraries included in LLVM carry separate
-  BSD-compatible licenses. See src/llvm/LICENSE.txt for
-  details.
+  BSD-compatible licenses. See src/llvm-project/llvm/LICENSE.TXT
+  for details.
 
 * compiler-rt, in src/compiler-rt is dual licensed under
   LLVM's license and MIT:
diff --git a/Cargo.lock b/Cargo.lock
index d4593c1ad234b..b93eaade65d61 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,3 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
 [[package]]
 name = "adler32"
 version = "1.0.3"
@@ -15,7 +17,7 @@ dependencies = [
 name = "alloc"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_xorshift 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -42,6 +44,11 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "arc-swap"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "arena"
 version = "0.0.0"
@@ -50,24 +57,25 @@ dependencies = [
 ]
 
 [[package]]
-name = "arrayvec"
-version = "0.4.7"
+name = "argon2rs"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
-name = "assert_cli"
-version = "0.6.2"
+name = "arrayref"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "arrayvec"
+version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "colored 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "environment 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -98,7 +106,7 @@ version = "0.1.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -126,6 +134,24 @@ name = "bitflags"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "blake2-rfc"
+version = "0.2.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "block-buffer"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arrayref 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-tools 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bootstrap"
 version = "0.0.0"
@@ -170,9 +196,14 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "build_helper"
 version = "0.1.0"
 
+[[package]]
+name = "byte-tools"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "bytecount"
-version = "0.4.0"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "packed_simd 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -183,6 +214,15 @@ name = "byteorder"
 version = "1.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "bytes"
+version = "0.4.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bytesize"
 version = "1.0.0"
@@ -190,7 +230,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cargo"
-version = "0.34.0"
+version = "0.35.0"
 dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "bufstream 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -198,13 +238,13 @@ dependencies = [
  "bytesize 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "crates-io 0.22.0",
+ "crates-io 0.23.0",
  "crossbeam-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "crypto-hash 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "curl 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "curl-sys 0.4.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "flate2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "fs2 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -215,7 +255,7 @@ dependencies = [
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "ignore 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "im-rc 12.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "im-rc 12.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jobserver 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -258,6 +298,18 @@ dependencies = [
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "cargo_metadata"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "cargotest2"
 version = "0.1.0"
@@ -318,7 +370,7 @@ dependencies = [
 name = "clippy"
 version = "0.0.212"
 dependencies = [
- "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cargo_metadata 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "clippy-mini-macro-test 0.2.0",
  "clippy_dev 0.0.1",
  "clippy_lints 0.0.212",
@@ -342,7 +394,7 @@ name = "clippy_dev"
 version = "0.0.1"
 dependencies = [
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -352,9 +404,9 @@ dependencies = [
 name = "clippy_lints"
 version = "0.0.212"
 dependencies = [
- "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cargo_metadata 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "if_chain 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "pulldown-cmark 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -411,7 +463,7 @@ dependencies = [
 
 [[package]]
 name = "compiler_builtins"
-version = "0.1.4"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -459,6 +511,11 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "constant_time_eq"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "core"
 version = "0.0.0"
@@ -482,10 +539,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "crates-io"
-version = "0.22.0"
+version = "0.23.0"
 dependencies = [
  "curl 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -520,6 +577,18 @@ dependencies = [
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "crossbeam-channel"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-epoch 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.2.0"
@@ -529,6 +598,15 @@ dependencies = [
  "crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-epoch 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-epoch"
 version = "0.3.1"
@@ -556,6 +634,19 @@ dependencies = [
  "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "crossbeam-epoch"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.2.2"
@@ -654,6 +745,14 @@ name = "difference"
 version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "digest"
+version = "0.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "directories"
 version = "1.0.2"
@@ -663,12 +762,22 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "dirs"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "redox_users 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "dlmalloc"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
@@ -724,11 +833,6 @@ dependencies = [
  "termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "environment"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "error-chain"
 version = "0.11.0"
@@ -754,16 +858,16 @@ dependencies = [
 
 [[package]]
 name = "failure"
-version = "0.1.3"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "failure_derive"
-version = "0.1.3"
+version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.24 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -772,6 +876,11 @@ dependencies = [
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "fake-simd"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "filetime"
 version = "0.2.4"
@@ -826,7 +935,7 @@ name = "fortanix-sgx-abi"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -889,6 +998,14 @@ dependencies = [
  "termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "generic-array"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "getopts"
 version = "0.2.17"
@@ -955,6 +1072,22 @@ dependencies = [
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "handlebars"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_derive 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quick-error 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.0"
@@ -1032,7 +1165,7 @@ dependencies = [
 
 [[package]]
 name = "im-rc"
-version = "12.2.0"
+version = "12.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1054,6 +1187,15 @@ dependencies = [
  "xz2 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "iovec"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "is-match"
 version = "0.1.0"
@@ -1067,6 +1209,14 @@ dependencies = [
  "either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "itoa"
 version = "0.4.3"
@@ -1099,7 +1249,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "jsonrpc-core"
-version = "9.0.0"
+version = "10.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1118,21 +1268,6 @@ dependencies = [
  "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "languageserver-types"
-version = "0.51.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-derive 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "url_serde 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "lazy_static"
 version = "0.2.11"
@@ -1232,6 +1367,31 @@ dependencies = [
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "lsp-codec"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bytes 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "lsp-types"
+version = "0.55.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-derive 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url_serde 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "lzma-sys"
 version = "0.1.10"
@@ -1306,6 +1466,34 @@ dependencies = [
  "toml-query 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "mdbook"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ammonia 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "elasticlunr-rs 2.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "handlebars 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "open 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pulldown-cmark 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "shlex 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tempfile 3.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "toml-query 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "memchr"
 version = "2.1.1"
@@ -1332,7 +1520,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "minifier"
-version = "0.0.26"
+version = "0.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "macro-utils 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1366,6 +1554,56 @@ dependencies = [
  "miniz_oxide 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "mio"
+version = "0.6.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "mio-named-pipes"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "miow 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "mio-uds"
+version = "0.6.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "miow"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "miow"
 version = "0.3.3"
@@ -1388,9 +1626,20 @@ dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-workspace-hack 1.0.0",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "shell-escape 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "vergen 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "net2"
+version = "0.2.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "new_debug_unreachable"
 version = "1.0.1"
@@ -1446,8 +1695,8 @@ name = "opener"
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1519,7 +1768,7 @@ dependencies = [
 name = "panic_abort"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1529,7 +1778,7 @@ name = "panic_unwind"
 version = "0.0.0"
 dependencies = [
  "alloc 0.0.0",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
  "unwind 0.0.0",
@@ -1544,6 +1793,15 @@ dependencies = [
  "parking_lot_core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "parking_lot"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "lock_api 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "parking_lot_core"
 version = "0.3.0"
@@ -1555,6 +1813,18 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "parking_lot_core"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "1.0.1"
@@ -1565,6 +1835,14 @@ name = "pest"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "pest"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ucd-trie 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "pest_derive"
 version = "1.0.8"
@@ -1575,6 +1853,37 @@ dependencies = [
  "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "pest_derive"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "pest 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_generator 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "pest 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_meta 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.22 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "maplit 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha-1 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "petgraph"
 version = "0.4.13"
@@ -1682,7 +1991,7 @@ name = "profiler_builtins"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -1754,7 +2063,7 @@ dependencies = [
 
 [[package]]
 name = "racer"
-version = "2.1.16"
+version = "2.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1764,8 +2073,8 @@ dependencies = [
  "humantime 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-syntax 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-syntax 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1897,6 +2206,17 @@ dependencies = [
  "redox_syscall 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "redox_users"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "argon2rs 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "redox_syscall 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex"
 version = "0.2.11"
@@ -1955,41 +2275,48 @@ dependencies = [
 
 [[package]]
 name = "rls"
-version = "1.31.6"
+version = "1.34.0"
 dependencies = [
- "cargo 0.34.0",
- "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cargo 0.35.0",
+ "cargo_metadata 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "clippy_lints 0.0.212",
- "crossbeam-channel 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-channel 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heck 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "home 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "jsonrpc-core 9.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "languageserver-types 0.51.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jsonrpc-core 10.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lsp-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lsp-types 0.55.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ordslice 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "racer 2.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "racer 2.1.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-analysis 0.16.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-analysis 0.16.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-blacklist 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-data 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-data 0.18.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-rustc 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rls-vfs 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-workspace-hack 1.0.0",
  "rustc_tools_util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustfmt-nightly 1.0.1",
+ "rustfmt-nightly 1.0.3",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_ignored 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-process 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1997,7 +2324,7 @@ dependencies = [
 
 [[package]]
 name = "rls-analysis"
-version = "0.16.10"
+version = "0.16.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "derive-new 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2005,8 +2332,8 @@ dependencies = [
  "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "json 0.11.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-data 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-data 0.18.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2017,10 +2344,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rls-data"
-version = "0.18.1"
+version = "0.18.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2033,7 +2360,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rls-span"
-version = "0.4.0"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2047,7 +2374,7 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2056,6 +2383,7 @@ version = "0.1.0"
 dependencies = [
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "mdbook 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mdbook 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2073,6 +2401,7 @@ dependencies = [
  "jobserver 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "polonius-engine 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2092,20 +2421,20 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-arena"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "rustc-ap-rustc_data_structures 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-graphviz"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rustc-ap-rustc_cratesio_shim"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2115,16 +2444,16 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_data_structures"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "ena 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-graphviz 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_cratesio_shim 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-graphviz 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_cratesio_shim 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-rayon-core 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2134,34 +2463,34 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-rustc_errors"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_cratesio_shim 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-syntax_pos 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_cratesio_shim 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-syntax_pos 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-rustc_target"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_cratesio_shim 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_cratesio_shim 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-serialize"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2169,29 +2498,29 @@ dependencies = [
 
 [[package]]
 name = "rustc-ap-syntax"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_errors 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_target 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-syntax_pos 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_errors 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_target 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-syntax_pos 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "scoped-tls 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rustc-ap-syntax_pos"
-version = "306.0.0"
+version = "373.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-arena 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_data_structures 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-serialize 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-arena 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_data_structures 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-serialize 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "scoped-tls 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2201,7 +2530,7 @@ name = "rustc-demangle"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-std-workspace-core 1.0.0",
 ]
 
@@ -2301,7 +2630,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2495,7 +2824,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2522,7 +2851,6 @@ name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "graphviz 0.0.0",
@@ -2547,7 +2875,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2561,6 +2889,7 @@ dependencies = [
  "rustc_errors 0.0.0",
  "rustc_mir 0.0.0",
  "syntax 0.0.0",
+ "syntax_ext 0.0.0",
  "syntax_pos 0.0.0",
 ]
 
@@ -2579,6 +2908,7 @@ dependencies = [
 name = "rustc_privacy"
 version = "0.0.0"
 dependencies = [
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_typeck 0.0.0",
@@ -2606,8 +2936,8 @@ name = "rustc_save_analysis"
 version = "0.0.0"
 dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-data 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rls-span 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-data 0.18.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rls-span 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc 0.0.0",
  "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_codegen_utils 0.0.0",
@@ -2661,7 +2991,7 @@ dependencies = [
  "alloc 0.0.0",
  "build_helper 0.1.0",
  "cmake 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
 ]
 
@@ -2692,7 +3022,7 @@ dependencies = [
 name = "rustdoc"
 version = "0.0.0"
 dependencies = [
- "minifier 0.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
+ "minifier 0.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "pulldown-cmark 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2714,7 +3044,7 @@ name = "rustfix"
 version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2723,24 +3053,24 @@ dependencies = [
 
 [[package]]
 name = "rustfmt-nightly"
-version = "1.0.1"
+version = "1.0.3"
 dependencies = [
- "assert_cli 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "bytecount 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cargo_metadata 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bytecount 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cargo_metadata 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive-new 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "diff 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.5.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "dirs 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.17 (registry+https://github.com/rust-lang/crates.io-index)",
- "itertools 0.7.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-rustc_target 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-syntax 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-ap-syntax_pos 306.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-rustc_target 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-syntax 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-ap-syntax_pos 373.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-workspace-hack 1.0.0",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2748,6 +3078,8 @@ dependencies = [
  "term 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode_categories 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2788,6 +3120,11 @@ name = "scoped-tls"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "scoped_threadpool"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "scopeguard"
 version = "0.3.3"
@@ -2850,6 +3187,17 @@ dependencies = [
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sha-1"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block-buffer 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-tools 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "digest 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "shell-escape"
 version = "0.1.4"
@@ -2860,11 +3208,25 @@ name = "shlex"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "signal-hook"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arc-swap 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "siphasher"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
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+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "smallvec"
 version = "0.6.7"
@@ -2896,9 +3258,9 @@ dependencies = [
  "alloc 0.0.0",
  "backtrace-sys 0.1.27 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
- "dlmalloc 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "dlmalloc 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "fortanix-sgx-abi 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
  "panic_abort 0.0.0",
@@ -3154,6 +3516,194 @@ dependencies = [
  "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
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+ "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-current-thread 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-executor 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
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+ "tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-threadpool 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-timer 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-udp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-uds 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
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+
+[[package]]
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+ "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-io 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
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+
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+ "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "iovec 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mio-uds 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-io 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-reactor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "toml"
 version = "0.4.10"
@@ -3174,11 +3724,28 @@ dependencies = [
  "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "toml-query"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "is-match 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "typenum"
 version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ucd-util"
 version = "0.1.3"
@@ -3217,6 +3784,11 @@ name = "unicode-xid"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "unicode_categories"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "unreachable"
 version = "1.0.0"
@@ -3237,7 +3809,7 @@ dependencies = [
 name = "unwind"
 version = "0.0.0"
 dependencies = [
- "compiler_builtins 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "compiler_builtins 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -3288,7 +3860,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
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  "chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3365,6 +3937,15 @@ dependencies = [
  "winapi-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
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+dependencies = [
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+ "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "xattr"
 version = "0.2.2"
@@ -3391,8 +3972,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum aho-corasick 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)" = "1e9a933f4e58658d7b12defcf96dc5c720f20832deebe3e0a19efd3b6aaeeb9e"
 "checksum ammonia 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fd4c682378117e4186a492b2252b9537990e1617f44aed9788b9a1149de45477"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+"checksum arc-swap 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "1025aeae2b664ca0ea726a89d574fe8f4e77dd712d443236ad1de00379450cf6"
+"checksum argon2rs 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "3f67b0b6a86dae6e67ff4ca2b6201396074996379fba2b92ff649126f37cb392"
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 "checksum rustc-demangle 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "82ae957aa1b3055d8e086486723c0ccd3d7b8fa190ae8fa2e35543b6171c810e"
 "checksum rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7540fc8b0c49f096ee9c961cda096467dce8084bec6bdca2fc83895fd9b28cb8"
 "checksum rustc-rayon 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8c6d5a683c6ba4ed37959097e88d71c9e8e26659a3cb5be8b389078e7ad45306"
@@ -3604,6 +4216,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum same-file 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8f20c4be53a8a1ff4c1f1b2bd14570d2f634628709752f0702ecdd2b3f9a5267"
 "checksum schannel 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "0e1a231dc10abf6749cfa5d7767f25888d484201accbd919b66ab5413c502d56"
 "checksum scoped-tls 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "332ffa32bf586782a3efaeb58f127980944bbc8c4d6913a86107ac2a5ab24b28"
+"checksum scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
@@ -3611,9 +4224,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum serde_derive 1.0.81 (registry+https://github.com/rust-lang/crates.io-index)" = "477b13b646f5b5b56fc95bedfc3b550d12141ce84f466f6c44b9a17589923885"
 "checksum serde_ignored 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "190e9765dcedb56be63b6e0993a006c7e3b071a016a304736e4a315dc01fb142"
 "checksum serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)" = "c37ccd6be3ed1fdf419ee848f7c758eb31b054d7cd3ae3600e3bae0adf569811"
+"checksum sha-1 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "51b9d1f3b5de8a167ab06834a7c883bd197f2191e1dda1a22d9ccfeedbf9aded"
 "checksum shell-escape 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "170a13e64f2a51b77a45702ba77287f5c6829375b04a69cf2222acd17d0cfab9"
 "checksum shlex 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
+"checksum signal-hook 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "1f272d1b7586bec132ed427f532dd418d8beca1ca7f2caf7df35569b1415a4b4"
 "checksum siphasher 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0df90a788073e8d0235a67e50441d47db7c8ad9debd91cbf43736a2a92d36537"
+"checksum slab 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 "checksum smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)" = "b73ea3738b47563803ef814925e69be00799a8c07420be8b996f8e98fb2336db"
 "checksum socket2 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "c4d11a52082057d87cb5caa31ad812f4504b97ab44732cd8359df2e9ff9f48e7"
 "checksum stable_deref_trait 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ffbc596e092fe5f598b12ef46cc03754085ac2f4d8c739ad61c4ae266cc3b3fa"
@@ -3636,9 +4252,25 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum textwrap 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "307686869c93e71f94da64286f9a9524c0f308a9e1c87a583de8e9c9039ad3f6"
 "checksum thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c6b53e329000edc2b34dbe8545fd20e55a333362d0a321909685a19bd28c3f1b"
 "checksum time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "d825be0eb33fda1a7e68012d51e9c7f451dc1a69391e7fdc197060bb8c56667b"
+"checksum tokio 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "4790d0be6f4ba6ae4f48190efa2ed7780c9e3567796abdb285003cf39840d9c5"
+"checksum tokio-codec 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5c501eceaf96f0e1793cf26beb63da3d11c738c4a943fdf3746d81d64684c39f"
+"checksum tokio-current-thread 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "331c8acc267855ec06eb0c94618dcbbfea45bed2d20b77252940095273fb58f6"
+"checksum tokio-executor 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "30c6dbf2d1ad1de300b393910e8a3aa272b724a400b6531da03eed99e329fbf0"
+"checksum tokio-fs 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0e9cbbc8a3698b7ab652340f46633364f9eaa928ddaaee79d8b8f356dd79a09d"
+"checksum tokio-io 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "b53aeb9d3f5ccf2ebb29e19788f96987fa1355f8fe45ea193928eaaaf3ae820f"
+"checksum tokio-process 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "88e1281e412013f1ff5787def044a9577a0bed059f451e835f1643201f8b777d"
+"checksum tokio-reactor 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "afbcdb0f0d2a1e4c440af82d7bbf0bf91a8a8c0575bcd20c05d15be7e9d3a02f"
+"checksum tokio-signal 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "dd6dc5276ea05ce379a16de90083ec80836440d5ef8a6a39545a3207373b8296"
+"checksum tokio-tcp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1d14b10654be682ac43efee27401d792507e30fd8d26389e1da3b185de2e4119"
+"checksum tokio-threadpool 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "17465013014410310f9f61fa10bf4724803c149ea1d51efece131c38efca93aa"
+"checksum tokio-timer 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "4f37f0111d76cc5da132fe9bc0590b9b9cfd079bc7e75ac3846278430a299ff8"
+"checksum tokio-udp 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "66268575b80f4a4a710ef83d087fdfeeabdce9b74c797535fbac18a2cb906e92"
+"checksum tokio-uds 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "037ffc3ba0e12a0ab4aca92e5234e0dedeb48fddf6ccd260f1f150a36a9f2445"
 "checksum toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "758664fc71a3a69038656bee8b6be6477d2a6c315a6b81f7081f591bffa4111f"
 "checksum toml-query 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6854664bfc6df0360c695480836ee90e2d0c965f06db291d10be9344792d43e8"
+"checksum toml-query 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ab234a943a2363ad774020e2f9474a38a85bc4396bace01a96380144aef17db3"
 "checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
+"checksum ucd-trie 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "71a9c5b1fe77426cf144cc30e49e955270f5086e31a6441dfa8b32efc09b9d77"
 "checksum ucd-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "535c204ee4d8434478593480b8f86ab45ec9aae0e83c568ca81abf0fd0e88f86"
 "checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
 "checksum unicode-normalization 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "6a0180bc61fc5a987082bfa111f4cc95c4caff7f9799f3e46df09163a937aa25"
@@ -3646,6 +4278,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
+"checksum unicode_categories 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "39ec24b3121d976906ece63c9daad25b85969647682eee313cb5779fdd69e14e"
 "checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
 "checksum url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dd4e7c0d531266369519a4aa4f399d748bd37043b00bde1e4ff1f60a120b355a"
 "checksum url_serde 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "74e7d099f1ee52f823d4bdd60c93c3602043c728f5db3b97bdb548467f7bddea"
@@ -3665,6 +4298,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum winapi-util 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "afc5508759c5bf4285e61feb862b6083c8480aec864fa17a81fdec6f69b461ab"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum wincolor 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "561ed901ae465d6185fa7864d63fbd5720d0ef718366c9a4dc83cf6170d7e9ba"
+"checksum ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d59cefebd0c892fa2dd6de581e937301d8552cb44489cdff035c6187cb63fa5e"
 "checksum xattr 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "244c3741f4240ef46274860397c7c74e50eb23624996930e484c16679633a54c"
 "checksum xz2 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "df8bf41d3030c3577c9458fd6640a05afbf43b150d0b531b16bd77d3f794f27a"
 "checksum yaml-rust 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e66366e18dc58b46801afbf2ca7661a9f59cc8c5962c29892b6039b4f86fa992"
diff --git a/README.md b/README.md
index cb1f06257ed15..514e420ca457c 100644
--- a/README.md
+++ b/README.md
@@ -13,9 +13,13 @@ Read ["Installation"] from [The Book].
 ["Installation"]: https://doc.rust-lang.org/book/ch01-01-installation.html
 [The Book]: https://doc.rust-lang.org/book/index.html
 
-## Building from Source
+## Installing from Source
 [building-from-source]: #building-from-source
 
+_Note: If you wish to contribute to the compiler, you should read
+[this chapter](https://rust-lang.github.io/rustc-guide/how-to-build-and-run.html)
+of the rustc-guide instead._
+
 ### Building on *nix
 1. Make sure you have installed the dependencies:
 
diff --git a/appveyor.yml b/appveyor.yml
index f043b8bfefca7..3a0cb8b4fceea 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -5,10 +5,9 @@ environment:
   # server goes down presumably. See #43333 for more info
   CARGO_HTTP_CHECK_REVOKE: false
 
-  # Recommended by AppVeyor this moves our builds to GCE which incurs a 3-4
-  # minute startup overhead, but that's paltry compared to our overall build
-  # times so we're will to eat the cost. This is intended to give us better
-  # performance I believe!
+  # Execute the builds on GCE instead of Hyper-V. Those builders have a 3-4
+  # minute startup overhead, but AppVeyor support recommended this as a
+  # possible solution for #58160 (spurious 259 exit codes)
   appveyor_build_worker_cloud: gce
 
   matrix:
diff --git a/config.toml.example b/config.toml.example
index 23943d34b7ca8..f45db37c33b86 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -90,12 +90,21 @@
 # with clang-cl, so this is special in that it only compiles LLVM with clang-cl
 #clang-cl = '/path/to/clang-cl.exe'
 
+# Pass extra compiler and linker flags to the LLVM CMake build.
+#cflags = "-fextra-flag"
+#cxxflags = "-fextra-flag"
+#ldflags = "-Wl,extra-flag"
+
 # Use libc++ when building LLVM instead of libstdc++. This is the default on
 # platforms already use libc++ as the default C++ library, but this option
 # allows you to use libc++ even on platforms when it's not. You need to ensure
 # that your host compiler ships with libc++.
 #use-libcxx = true
 
+# The value specified here will be passed as `-DLLVM_USE_LINKER` to CMake.
+#use-linker = "lld"
+
+
 # =============================================================================
 # General build configuration options
 # =============================================================================
@@ -312,8 +321,8 @@
 # Whether to always use incremental compilation when building rustc
 #incremental = false
 
-# Build rustc with experimental parallelization
-#experimental-parallel-queries = false
+# Build a multi-threaded rustc
+#parallel-compiler = false
 
 # The default linker that will be hard-coded into the generated compiler for
 # targets that don't specify linker explicitly in their target specifications.
diff --git a/src/README.md b/src/README.md
index 65228915866ea..14e773286bc6a 100644
--- a/src/README.md
+++ b/src/README.md
@@ -8,7 +8,6 @@ For more information on how various parts of the compiler work, see the [rustc g
 There is also useful content in the following READMEs, which are gradually being moved over to the guide:
 - https://github.com/rust-lang/rust/tree/master/src/librustc/ty/query
 - https://github.com/rust-lang/rust/tree/master/src/librustc/dep_graph
-- https://github.com/rust-lang/rust/blob/master/src/librustc/infer/region_constraints
 - https://github.com/rust-lang/rust/tree/master/src/librustc/infer/higher_ranked
 - https://github.com/rust-lang/rust/tree/master/src/librustc/infer/lexical_region_resolve
 
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index a0c75cd9e9476..7a765973e20f8 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -284,8 +284,8 @@ fn main() {
         }
     }
 
-    if env::var_os("RUSTC_PARALLEL_QUERIES").is_some() {
-        cmd.arg("--cfg").arg("parallel_queries");
+    if env::var_os("RUSTC_PARALLEL_COMPILER").is_some() {
+        cmd.arg("--cfg").arg("parallel_compiler");
     }
 
     if env::var_os("RUSTC_DENY_WARNINGS").is_some() && env::var_os("RUSTC_EXTERNAL_TOOL").is_none()
diff --git a/src/bootstrap/bin/rustdoc.rs b/src/bootstrap/bin/rustdoc.rs
index dec74e60c71f3..aeb15821b0bb7 100644
--- a/src/bootstrap/bin/rustdoc.rs
+++ b/src/bootstrap/bin/rustdoc.rs
@@ -16,6 +16,7 @@ fn main() {
     let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
+    let mut has_unstable = false;
 
     use std::str::FromStr;
 
@@ -54,9 +55,22 @@ fn main() {
     // it up so we can make rustdoc print this into the docs
     if let Some(version) = env::var_os("RUSTDOC_CRATE_VERSION") {
         // This "unstable-options" can be removed when `--crate-version` is stabilized
-        cmd.arg("-Z")
-           .arg("unstable-options")
-           .arg("--crate-version").arg(version);
+        if !has_unstable {
+            cmd.arg("-Z")
+               .arg("unstable-options");
+        }
+        cmd.arg("--crate-version").arg(version);
+        has_unstable = true;
+    }
+
+    // Needed to be able to run all rustdoc tests.
+    if let Some(_) = env::var_os("RUSTDOC_GENERATE_REDIRECT_PAGES") {
+        // This "unstable-options" can be removed when `--generate-redirect-pages` is stabilized
+        if !has_unstable {
+            cmd.arg("-Z")
+               .arg("unstable-options");
+        }
+        cmd.arg("--generate-redirect-pages");
     }
 
     if verbose > 1 {
diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index f3dbae6909a4d..119b38bcc99dc 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -230,6 +230,9 @@ def default_build_triple():
         err = "unknown OS type: {}".format(ostype)
         sys.exit(err)
 
+    if cputype == 'powerpc' and ostype == 'unknown-freebsd':
+        cputype = subprocess.check_output(
+              ['uname', '-p']).strip().decode(default_encoding)
     cputype_mapper = {
         'BePC': 'i686',
         'aarch64': 'aarch64',
@@ -698,21 +701,13 @@ def update_submodules(self):
         filtered_submodules = []
         submodules_names = []
         for module in submodules:
-            if module.endswith("llvm"):
-                if self.get_toml('llvm-config'):
+            if module.endswith("llvm-project"):
+                if self.get_toml('llvm-config') and self.get_toml('lld') != 'true':
                     continue
             if module.endswith("llvm-emscripten"):
                 backends = self.get_toml('codegen-backends')
                 if backends is None or not 'emscripten' in backends:
                     continue
-            if module.endswith("lld"):
-                config = self.get_toml('lld')
-                if config is None or config == 'false':
-                    continue
-            if module.endswith("lldb") or module.endswith("clang"):
-                config = self.get_toml('lldb')
-                if config is None or config == 'false':
-                    continue
             check = self.check_submodule(module, slow_submodules)
             filtered_submodules.append((module, check))
             submodules_names.append(module)
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 9c58f5b179fd8..9d037dad9ccbd 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -21,7 +21,7 @@ use crate::install;
 use crate::native;
 use crate::test;
 use crate::tool;
-use crate::util::{add_lib_path, exe, libdir};
+use crate::util::{self, add_lib_path, exe, libdir};
 use crate::{Build, DocTests, Mode, GitRepo};
 
 pub use crate::Compiler;
@@ -60,17 +60,17 @@ pub trait Step: 'static + Clone + Debug + PartialEq + Eq + Hash {
     /// Run this rule for all hosts without cross compiling.
     const ONLY_HOSTS: bool = false;
 
-    /// Primary function to execute this rule. Can call `builder.ensure(...)`
+    /// Primary function to execute this rule. Can call `builder.ensure()`
     /// with other steps to run those.
     fn run(self, builder: &Builder) -> Self::Output;
 
     /// When bootstrap is passed a set of paths, this controls whether this rule
     /// will execute. However, it does not get called in a "default" context
-    /// when we are not passed any paths; in that case, make_run is called
+    /// when we are not passed any paths; in that case, `make_run` is called
     /// directly.
     fn should_run(run: ShouldRun) -> ShouldRun;
 
-    /// Build up a "root" rule, either as a default rule or from a path passed
+    /// Builds up a "root" rule, either as a default rule or from a path passed
     /// to us.
     ///
     /// When path is `None`, we are executing in a context where no paths were
@@ -378,14 +378,11 @@ impl<'a> Builder<'a> {
                 test::Debuginfo,
                 test::UiFullDeps,
                 test::RunPassFullDeps,
-                test::RunFailFullDeps,
                 test::Rustdoc,
                 test::Pretty,
                 test::RunPassPretty,
                 test::RunFailPretty,
                 test::RunPassValgrindPretty,
-                test::RunPassFullDepsPretty,
-                test::RunFailFullDepsPretty,
                 test::Crate,
                 test::CrateLibrustc,
                 test::CrateRustdoc,
@@ -403,6 +400,7 @@ impl<'a> Builder<'a> {
                 test::TheBook,
                 test::UnstableBook,
                 test::RustcBook,
+                test::EmbeddedBook,
                 test::Rustfmt,
                 test::Miri,
                 test::Clippy,
@@ -433,6 +431,7 @@ impl<'a> Builder<'a> {
                 doc::RustByExample,
                 doc::RustcBook,
                 doc::CargoBook,
+                doc::EmbeddedBook,
                 doc::EditionGuide,
             ),
             Kind::Dist => describe!(
@@ -649,7 +648,7 @@ impl<'a> Builder<'a> {
         add_lib_path(vec![self.rustc_libdir(compiler)], cmd);
     }
 
-    /// Get a path to the compiler specified.
+    /// Gets a path to the compiler specified.
     pub fn rustc(&self, compiler: Compiler) -> PathBuf {
         if compiler.is_snapshot(self) {
             self.initial_rustc.clone()
@@ -660,6 +659,15 @@ impl<'a> Builder<'a> {
         }
     }
 
+    /// Gets the paths to all of the compiler's codegen backends.
+    fn codegen_backends(&self, compiler: Compiler) -> impl Iterator<Item = PathBuf> {
+        fs::read_dir(self.sysroot_codegen_backends(compiler))
+            .into_iter()
+            .flatten()
+            .filter_map(Result::ok)
+            .map(|entry| entry.path())
+    }
+
     pub fn rustdoc(&self, host: Interned<String>) -> PathBuf {
         self.ensure(tool::Rustdoc { host })
     }
@@ -669,10 +677,9 @@ impl<'a> Builder<'a> {
         let compiler = self.compiler(self.top_stage, host);
         cmd.env("RUSTC_STAGE", compiler.stage.to_string())
             .env("RUSTC_SYSROOT", self.sysroot(compiler))
-            .env(
-                "RUSTDOC_LIBDIR",
-                self.sysroot_libdir(compiler, self.config.build),
-            )
+            // Note that this is *not* the sysroot_libdir because rustdoc must be linked
+            // equivalently to rustc.
+            .env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler))
             .env("CFG_RELEASE_CHANNEL", &self.config.channel)
             .env("RUSTDOC_REAL", self.rustdoc(host))
             .env("RUSTDOC_CRATE_VERSION", self.rust_version())
@@ -750,6 +757,9 @@ impl<'a> Builder<'a> {
             match mode {
                 Mode::Std => {
                     self.clear_if_dirty(&my_out, &self.rustc(compiler));
+                    for backend in self.codegen_backends(compiler) {
+                        self.clear_if_dirty(&my_out, &backend);
+                    }
                 },
                 Mode::Test => {
                     self.clear_if_dirty(&my_out, &libstd_stamp);
@@ -782,6 +792,13 @@ impl<'a> Builder<'a> {
             .env("CARGO_TARGET_DIR", out_dir)
             .arg(cmd);
 
+        // See comment in librustc_llvm/build.rs for why this is necessary, largely llvm-config
+        // needs to not accidentally link to libLLVM in stage0/lib.
+        cargo.env("REAL_LIBRARY_PATH_VAR", &util::dylib_path_var());
+        if let Some(e) = env::var_os(util::dylib_path_var()) {
+            cargo.env("REAL_LIBRARY_PATH", e);
+        }
+
         if cmd != "install" {
             cargo.arg("--target")
                  .arg(target);
@@ -856,7 +873,7 @@ impl<'a> Builder<'a> {
         } else {
             &maybe_sysroot
         };
-        let libdir = sysroot.join(libdir(&compiler.host));
+        let libdir = self.rustc_libdir(compiler);
 
         // Customize the compiler we're running. Specify the compiler to cargo
         // as our shim and then pass it some various options used to configure
@@ -898,7 +915,7 @@ impl<'a> Builder<'a> {
             cargo.env("RUSTC_ERROR_FORMAT", error_format);
         }
         if cmd != "build" && cmd != "check" && cmd != "rustc" && want_rustdoc {
-            cargo.env("RUSTDOC_LIBDIR", self.sysroot_libdir(compiler, self.config.build));
+            cargo.env("RUSTDOC_LIBDIR", self.rustc_libdir(compiler));
         }
 
         if mode.is_tool() {
@@ -982,6 +999,9 @@ impl<'a> Builder<'a> {
 
         if self.config.incremental {
             cargo.env("CARGO_INCREMENTAL", "1");
+        } else {
+            // Don't rely on any default setting for incr. comp. in Cargo
+            cargo.env("CARGO_INCREMENTAL", "0");
         }
 
         if let Some(ref on_fail) = self.config.on_fail {
@@ -998,8 +1018,7 @@ impl<'a> Builder<'a> {
 
         cargo.env("RUSTC_VERBOSE", self.verbosity.to_string());
 
-        // in std, we want to avoid denying warnings for stage 0 as that makes cfg's painful.
-        if self.config.deny_warnings && !(mode == Mode::Std && stage == 0) {
+        if self.config.deny_warnings {
             cargo.env("RUSTC_DENY_WARNINGS", "1");
         }
 
@@ -1032,29 +1051,24 @@ impl<'a> Builder<'a> {
                 }
             };
             let cc = ccacheify(&self.cc(target));
-            cargo.env(format!("CC_{}", target), &cc).env("CC", &cc);
+            cargo.env(format!("CC_{}", target), &cc);
 
             let cflags = self.cflags(target, GitRepo::Rustc).join(" ");
             cargo
-                .env(format!("CFLAGS_{}", target), cflags.clone())
-                .env("CFLAGS", cflags.clone());
+                .env(format!("CFLAGS_{}", target), cflags.clone());
 
             if let Some(ar) = self.ar(target) {
                 let ranlib = format!("{} s", ar.display());
                 cargo
                     .env(format!("AR_{}", target), ar)
-                    .env("AR", ar)
-                    .env(format!("RANLIB_{}", target), ranlib.clone())
-                    .env("RANLIB", ranlib);
+                    .env(format!("RANLIB_{}", target), ranlib);
             }
 
             if let Ok(cxx) = self.cxx(target) {
                 let cxx = ccacheify(&cxx);
                 cargo
                     .env(format!("CXX_{}", target), &cxx)
-                    .env("CXX", &cxx)
-                    .env(format!("CXXFLAGS_{}", target), cflags.clone())
-                    .env("CXXFLAGS", cflags);
+                    .env(format!("CXXFLAGS_{}", target), cflags);
             }
         }
 
diff --git a/src/bootstrap/cache.rs b/src/bootstrap/cache.rs
index ea8bc657a57aa..5f84816789a68 100644
--- a/src/bootstrap/cache.rs
+++ b/src/bootstrap/cache.rs
@@ -227,10 +227,10 @@ lazy_static! {
     pub static ref INTERNER: Interner = Interner::default();
 }
 
-/// This is essentially a HashMap which allows storing any type in its input and
+/// This is essentially a `HashMap` which allows storing any type in its input and
 /// any type in its output. It is a write-once cache; values are never evicted,
 /// which means that references to the value can safely be returned from the
-/// get() method.
+/// `get()` method.
 #[derive(Debug)]
 pub struct Cache(
     RefCell<HashMap<
diff --git a/src/bootstrap/channel.rs b/src/bootstrap/channel.rs
index 63741b9b677b4..0b2f62485c9ee 100644
--- a/src/bootstrap/channel.rs
+++ b/src/bootstrap/channel.rs
@@ -14,7 +14,7 @@ use crate::Build;
 use crate::config::Config;
 
 // The version number
-pub const CFG_RELEASE_NUM: &str = "1.33.0";
+pub const CFG_RELEASE_NUM: &str = "1.34.0";
 
 pub struct GitInfo {
     inner: Option<Info>,
diff --git a/src/bootstrap/check.rs b/src/bootstrap/check.rs
index cc539d4c89571..2a2533a3c1407 100644
--- a/src/bootstrap/check.rs
+++ b/src/bootstrap/check.rs
@@ -66,7 +66,7 @@ impl Step for Rustc {
         });
     }
 
-    /// Build the compiler.
+    /// Builds the compiler.
     ///
     /// This will build the compiler for a particular stage of the build using
     /// the `compiler` targeting the `target` architecture. The artifacts
diff --git a/src/bootstrap/clean.rs b/src/bootstrap/clean.rs
index 74a2b7e4aa98b..b52e1a7b0e681 100644
--- a/src/bootstrap/clean.rs
+++ b/src/bootstrap/clean.rs
@@ -3,7 +3,7 @@
 //! Responsible for cleaning out a build directory of all old and stale
 //! artifacts to prepare for a fresh build. Currently doesn't remove the
 //! `build/cache` directory (download cache) or the `build/$target/llvm`
-//! directory unless the --all flag is present.
+//! directory unless the `--all` flag is present.
 
 use std::fs;
 use std::io::{self, ErrorKind};
diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index b581271663e7e..8fabb8c3fd08f 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -48,7 +48,7 @@ impl Step for Std {
         });
     }
 
-    /// Build the standard library.
+    /// Builds the standard library.
     ///
     /// This will build the standard library for a particular stage of the build
     /// using the `compiler` targeting the `target` architecture. The artifacts
@@ -269,7 +269,7 @@ impl Step for StartupObjects {
         });
     }
 
-    /// Build and prepare startup objects like rsbegin.o and rsend.o
+    /// Builds and prepare startup objects like rsbegin.o and rsend.o
     ///
     /// These are primarily used on Windows right now for linking executables/dlls.
     /// They don't require any library support as they're just plain old object
@@ -334,7 +334,7 @@ impl Step for Test {
         });
     }
 
-    /// Build libtest.
+    /// Builds libtest.
     ///
     /// This will build libtest and supporting libraries for a particular stage of
     /// the build using the `compiler` targeting the `target` architecture. The
@@ -455,7 +455,7 @@ impl Step for Rustc {
         });
     }
 
-    /// Build the compiler.
+    /// Builds the compiler.
     ///
     /// This will build the compiler for a particular stage of the build using
     /// the `compiler` targeting the `target` architecture. The artifacts
@@ -554,8 +554,8 @@ pub fn rustc_cargo_env(builder: &Builder, cargo: &mut Command) {
     if let Some(ref s) = builder.config.rustc_default_linker {
         cargo.env("CFG_DEFAULT_LINKER", s);
     }
-    if builder.config.rustc_parallel_queries {
-        cargo.env("RUSTC_PARALLEL_QUERIES", "1");
+    if builder.config.rustc_parallel {
+        cargo.env("RUSTC_PARALLEL_COMPILER", "1");
     }
     if builder.config.rust_verify_llvm_ir {
         cargo.env("RUSTC_VERIFY_LLVM_IR", "1");
@@ -712,6 +712,7 @@ pub fn build_codegen_backend(builder: &Builder,
             if builder.is_rust_llvm(target) && backend != "emscripten" {
                 cargo.env("LLVM_RUSTLLVM", "1");
             }
+
             cargo.env("LLVM_CONFIG", &llvm_config);
             if backend != "emscripten" {
                 let target_config = builder.config.target_config.get(&target);
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 9421817ae6d8e..7d3e584f1a6fa 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -77,11 +77,15 @@ pub struct Config {
     pub llvm_experimental_targets: String,
     pub llvm_link_jobs: Option<u32>,
     pub llvm_version_suffix: Option<String>,
+    pub llvm_use_linker: Option<String>,
 
     pub lld_enabled: bool,
     pub lldb_enabled: bool,
     pub llvm_tools_enabled: bool,
 
+    pub llvm_cflags: Option<String>,
+    pub llvm_cxxflags: Option<String>,
+    pub llvm_ldflags: Option<String>,
     pub llvm_use_libcxx: bool,
 
     // rust codegen options
@@ -94,7 +98,7 @@ pub struct Config {
     pub rust_debuginfo_only_std: bool,
     pub rust_debuginfo_tools: bool,
     pub rust_rpath: bool,
-    pub rustc_parallel_queries: bool,
+    pub rustc_parallel: bool,
     pub rustc_default_linker: Option<String>,
     pub rust_optimize_tests: bool,
     pub rust_debuginfo_tests: bool,
@@ -254,7 +258,11 @@ struct Llvm {
     link_shared: Option<bool>,
     version_suffix: Option<String>,
     clang_cl: Option<String>,
+    cflags: Option<String>,
+    cxxflags: Option<String>,
+    ldflags: Option<String>,
     use_libcxx: Option<bool>,
+    use_linker: Option<String>,
 }
 
 #[derive(Deserialize, Default, Clone)]
@@ -292,7 +300,7 @@ struct Rust {
     debuginfo_lines: Option<bool>,
     debuginfo_only_std: Option<bool>,
     debuginfo_tools: Option<bool>,
-    experimental_parallel_queries: Option<bool>,
+    parallel_compiler: Option<bool>,
     backtrace: Option<bool>,
     default_linker: Option<String>,
     channel: Option<String>,
@@ -516,7 +524,12 @@ impl Config {
             config.llvm_link_jobs = llvm.link_jobs;
             config.llvm_version_suffix = llvm.version_suffix.clone();
             config.llvm_clang_cl = llvm.clang_cl.clone();
+
+            config.llvm_cflags = llvm.cflags.clone();
+            config.llvm_cxxflags = llvm.cxxflags.clone();
+            config.llvm_ldflags = llvm.ldflags.clone();
             set(&mut config.llvm_use_libcxx, llvm.use_libcxx);
+            config.llvm_use_linker = llvm.use_linker.clone();
         }
 
         if let Some(ref rust) = toml.rust {
@@ -547,7 +560,7 @@ impl Config {
             set(&mut config.lld_enabled, rust.lld);
             set(&mut config.lldb_enabled, rust.lldb);
             set(&mut config.llvm_tools_enabled, rust.llvm_tools);
-            config.rustc_parallel_queries = rust.experimental_parallel_queries.unwrap_or(false);
+            config.rustc_parallel = rust.parallel_compiler.unwrap_or(false);
             config.rustc_default_linker = rust.default_linker.clone();
             config.musl_root = rust.musl_root.clone().map(PathBuf::from);
             config.save_toolstates = rust.save_toolstates.clone().map(PathBuf::from);
diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
index b0c3c9702498d..b2d8f2d8ebfcf 100755
--- a/src/bootstrap/configure.py
+++ b/src/bootstrap/configure.py
@@ -35,7 +35,7 @@ def v(*args):
 o("docs", "build.docs", "build standard library documentation")
 o("compiler-docs", "build.compiler-docs", "build compiler documentation")
 o("optimize-tests", "rust.optimize-tests", "build tests with optimizations")
-o("experimental-parallel-queries", "rust.experimental-parallel-queries", "build rustc with experimental parallelization")
+o("parallel-compiler", "rust.parallel-compiler", "build a multi-threaded rustc")
 o("test-miri", "rust.test-miri", "run miri's test suite")
 o("debuginfo-tests", "rust.debuginfo-tests", "build tests with debugger metadata")
 o("verbose-tests", "rust.verbose-tests", "enable verbose output when running tests")
@@ -64,6 +64,10 @@ def v(*args):
 o("missing-tools", "dist.missing-tools", "allow failures when building tools")
 o("use-libcxx", "llvm.use_libcxx", "build LLVM with libc++")
 
+o("cflags", "llvm.cflags", "build LLVM with these extra compiler flags")
+o("cxxflags", "llvm.cxxflags", "build LLVM with these extra compiler flags")
+o("ldflags", "llvm.ldflags", "build LLVM with these extra linker flags")
+
 # Optimization and debugging options. These may be overridden by the release
 # channel, etc.
 o("optimize", "rust.optimize", "build optimized rust code")
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index df34dfe4544ae..bc1fdad356be3 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -23,7 +23,7 @@ use crate::builder::{Builder, RunConfig, ShouldRun, Step};
 use crate::compile;
 use crate::tool::{self, Tool};
 use crate::cache::{INTERNER, Interned};
-use time;
+use time::{self, Timespec};
 
 pub fn pkgname(builder: &Builder, component: &str) -> String {
     if component == "cargo" {
@@ -226,7 +226,7 @@ fn make_win_dist(
         let trim_chars: &[_] = &[' ', '='];
         let value =
             line[(idx + 1)..]
-                .trim_left_matches(trim_chars)
+                .trim_start_matches(trim_chars)
                 .split(';')
                 .map(PathBuf::from);
 
@@ -342,7 +342,7 @@ impl Step for Mingw {
         run.builder.ensure(Mingw { host: run.target });
     }
 
-    /// Build the `rust-mingw` installer component.
+    /// Builds the `rust-mingw` installer component.
     ///
     /// This contains all the bits and pieces to run the MinGW Windows targets
     /// without any extra installed software (e.g., we bundle gcc, libraries, etc).
@@ -528,7 +528,19 @@ impl Step for Rustc {
             t!(fs::create_dir_all(image.join("share/man/man1")));
             let man_src = builder.src.join("src/doc/man");
             let man_dst = image.join("share/man/man1");
-            let month_year = t!(time::strftime("%B %Y", &time::now()));
+
+            // Reproducible builds: If SOURCE_DATE_EPOCH is set, use that as the time.
+            let time = env::var("SOURCE_DATE_EPOCH")
+                .map(|timestamp| {
+                    let epoch = timestamp.parse().map_err(|err| {
+                        format!("could not parse SOURCE_DATE_EPOCH: {}", err)
+                    }).unwrap();
+
+                    time::at(Timespec::new(epoch, 0))
+                })
+                .unwrap_or_else(|_| time::now());
+
+            let month_year = t!(time::strftime("%B %Y", &time));
             // don't use our `bootstrap::util::{copy, cp_r}`, because those try
             // to hardlink, and we don't want to edit the source templates
             for file_entry in builder.read_dir(&man_src) {
@@ -602,6 +614,8 @@ impl Step for DebuggerScripts {
             // gdb debugger scripts
             builder.install(&builder.src.join("src/etc/rust-gdb"), &sysroot.join("bin"),
                     0o755);
+            builder.install(&builder.src.join("src/etc/rust-gdbgui"), &sysroot.join("bin"),
+                    0o755);
 
             cp_debugger_script("gdb_load_rust_pretty_printers.py");
             cp_debugger_script("gdb_rust_pretty_printing.py");
@@ -786,7 +800,24 @@ fn copy_src_dirs(builder: &Builder, src_dirs: &[&str], exclude_dirs: &[&str], ds
         if spath.ends_with("~") || spath.ends_with(".pyc") {
             return false
         }
-        if (spath.contains("llvm/test") || spath.contains("llvm\\test")) &&
+
+        const LLVM_PROJECTS: &[&str] = &[
+            "llvm-project/clang", "llvm-project\\clang",
+            "llvm-project/lld", "llvm-project\\lld",
+            "llvm-project/lldb", "llvm-project\\lldb",
+            "llvm-project/llvm", "llvm-project\\llvm",
+        ];
+        if spath.contains("llvm-project") && !spath.ends_with("llvm-project")
+            && !LLVM_PROJECTS.iter().any(|path| spath.contains(path))
+        {
+            return false;
+        }
+
+        const LLVM_TEST: &[&str] = &[
+            "llvm-project/llvm/test", "llvm-project\\llvm\\test",
+            "llvm-emscripten/test", "llvm-emscripten\\test",
+        ];
+        if LLVM_TEST.iter().any(|path| spath.contains(path)) &&
             (spath.ends_with(".ll") ||
              spath.ends_with(".td") ||
              spath.ends_with(".s")) {
@@ -2074,7 +2105,7 @@ impl Step for LlvmTools {
         }
 
         builder.info(&format!("Dist LlvmTools stage{} ({})", stage, target));
-        let src = builder.src.join("src/llvm");
+        let src = builder.src.join("src/llvm-project/llvm");
         let name = pkgname(builder, "llvm-tools");
 
         let tmp = tmpdir(builder);
@@ -2133,7 +2164,7 @@ impl Step for Lldb {
     const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun) -> ShouldRun {
-        run.path("src/tools/lldb")
+        run.path("src/llvm-project/lldb").path("src/tools/lldb")
     }
 
     fn make_run(run: RunConfig) {
@@ -2158,7 +2189,7 @@ impl Step for Lldb {
         }
 
         builder.info(&format!("Dist Lldb ({})", target));
-        let src = builder.src.join("src/tools/lldb");
+        let src = builder.src.join("src/llvm-project/lldb");
         let name = pkgname(builder, "lldb");
 
         let tmp = tmpdir(builder);
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index eec193c21f5db..660f9b9ef578a 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -23,7 +23,7 @@ use crate::cache::{INTERNER, Interned};
 use crate::config::Config;
 
 macro_rules! book {
-    ($($name:ident, $path:expr, $book_name:expr;)+) => {
+    ($($name:ident, $path:expr, $book_name:expr, $book_ver:expr;)+) => {
         $(
             #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
         pub struct $name {
@@ -49,6 +49,7 @@ macro_rules! book {
                 builder.ensure(Rustbook {
                     target: self.target,
                     name: INTERNER.intern_str($book_name),
+                    version: $book_ver,
                 })
             }
         }
@@ -56,19 +57,29 @@ macro_rules! book {
     }
 }
 
+// NOTE: When adding a book here, make sure to ALSO build the book by
+// adding a build step in `src/bootstrap/builder.rs`!
 book!(
-    Nomicon, "src/doc/nomicon", "nomicon";
-    Reference, "src/doc/reference", "reference";
-    EditionGuide, "src/doc/edition-guide", "edition-guide";
-    RustdocBook, "src/doc/rustdoc", "rustdoc";
-    RustcBook, "src/doc/rustc", "rustc";
-    RustByExample, "src/doc/rust-by-example", "rust-by-example";
+    EditionGuide, "src/doc/edition-guide", "edition-guide", RustbookVersion::MdBook1;
+    EmbeddedBook, "src/doc/embedded-book", "embedded-book", RustbookVersion::MdBook2;
+    Nomicon, "src/doc/nomicon", "nomicon", RustbookVersion::MdBook1;
+    Reference, "src/doc/reference", "reference", RustbookVersion::MdBook1;
+    RustByExample, "src/doc/rust-by-example", "rust-by-example", RustbookVersion::MdBook1;
+    RustcBook, "src/doc/rustc", "rustc", RustbookVersion::MdBook1;
+    RustdocBook, "src/doc/rustdoc", "rustdoc", RustbookVersion::MdBook1;
 );
 
+#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
+enum RustbookVersion {
+    MdBook1,
+    MdBook2,
+}
+
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 struct Rustbook {
     target: Interned<String>,
     name: Interned<String>,
+    version: RustbookVersion,
 }
 
 impl Step for Rustbook {
@@ -90,6 +101,7 @@ impl Step for Rustbook {
             target: self.target,
             name: self.name,
             src: INTERNER.intern_path(src),
+            version: self.version,
         });
     }
 }
@@ -122,6 +134,7 @@ impl Step for UnstableBook {
             target: self.target,
             name: INTERNER.intern_str("unstable-book"),
             src: builder.md_doc_out(self.target),
+            version: RustbookVersion::MdBook1,
         })
     }
 }
@@ -175,6 +188,7 @@ struct RustbookSrc {
     target: Interned<String>,
     name: Interned<String>,
     src: Interned<PathBuf>,
+    version: RustbookVersion,
 }
 
 impl Step for RustbookSrc {
@@ -205,11 +219,19 @@ impl Step for RustbookSrc {
         }
         builder.info(&format!("Rustbook ({}) - {}", target, name));
         let _ = fs::remove_dir_all(&out);
+
+        let vers = match self.version {
+            RustbookVersion::MdBook1 => "1",
+            RustbookVersion::MdBook2 => "2",
+        };
+
         builder.run(rustbook_cmd
                        .arg("build")
                        .arg(&src)
                        .arg("-d")
-                       .arg(out));
+                       .arg(out)
+                       .arg("-m")
+                       .arg(vers));
     }
 }
 
@@ -237,7 +259,7 @@ impl Step for TheBook {
         });
     }
 
-    /// Build the book and associated stuff.
+    /// Builds the book and associated stuff.
     ///
     /// We need to build:
     ///
@@ -255,6 +277,7 @@ impl Step for TheBook {
         builder.ensure(Rustbook {
             target,
             name: INTERNER.intern_string(name.to_string()),
+            version: RustbookVersion::MdBook1,
         });
 
         // building older edition redirects
@@ -263,18 +286,21 @@ impl Step for TheBook {
         builder.ensure(Rustbook {
             target,
             name: INTERNER.intern_string(source_name),
+            version: RustbookVersion::MdBook1,
         });
 
         let source_name = format!("{}/second-edition", name);
         builder.ensure(Rustbook {
             target,
             name: INTERNER.intern_string(source_name),
+            version: RustbookVersion::MdBook1,
         });
 
         let source_name = format!("{}/2018-edition", name);
         builder.ensure(Rustbook {
             target,
             name: INTERNER.intern_string(source_name),
+            version: RustbookVersion::MdBook1,
         });
 
         // build the version info page and CSS
@@ -491,6 +517,7 @@ impl Step for Std {
             cargo.arg("--")
                  .arg("--markdown-css").arg("rust.css")
                  .arg("--markdown-no-toc")
+                 .arg("--generate-redirect-pages")
                  .arg("--index-page").arg(&builder.src.join("src/doc/index.md"));
 
             builder.run(&mut cargo);
@@ -555,7 +582,9 @@ impl Step for Test {
         let mut cargo = builder.cargo(compiler, Mode::Test, target, "doc");
         compile::test_cargo(builder, &compiler, target, &mut cargo);
 
-        cargo.arg("--no-deps").arg("-p").arg("test");
+        cargo.arg("--no-deps")
+             .arg("-p").arg("test")
+             .env("RUSTDOC_GENERATE_REDIRECT_PAGES", "1");
 
         builder.run(&mut cargo);
         builder.cp_r(&my_out, &out);
@@ -585,7 +614,7 @@ impl Step for WhitelistedRustc {
         });
     }
 
-    /// Generate whitelisted compiler crate documentation.
+    /// Generates whitelisted compiler crate documentation.
     ///
     /// This will generate all documentation for crates that are whitelisted
     /// to be included in the standard documentation. This documentation is
@@ -624,9 +653,9 @@ impl Step for WhitelistedRustc {
         // We don't want to build docs for internal compiler dependencies in this
         // step (there is another step for that). Therefore, we whitelist the crates
         // for which docs must be built.
-        cargo.arg("--no-deps");
         for krate in &["proc_macro"] {
-            cargo.arg("-p").arg(krate);
+            cargo.arg("-p").arg(krate)
+                 .env("RUSTDOC_GENERATE_REDIRECT_PAGES", "1");
         }
 
         builder.run(&mut cargo);
@@ -657,7 +686,7 @@ impl Step for Rustc {
         });
     }
 
-    /// Generate compiler documentation.
+    /// Generates compiler documentation.
     ///
     /// This will generate all documentation for compiler and dependencies.
     /// Compiler documentation is distributed separately, so we make sure
@@ -758,7 +787,7 @@ impl Step for Rustdoc {
         });
     }
 
-    /// Generate compiler documentation.
+    /// Generates compiler documentation.
     ///
     /// This will generate all documentation for compiler and dependencies.
     /// Compiler documentation is distributed separately, so we make sure
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index bddc6362389ad..6a93c95c3d97f 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -69,7 +69,7 @@
 //! ## Copying stage0 {std,test,rustc}
 //!
 //! This copies the build output from Cargo into
-//! `build/$HOST/stage0-sysroot/lib/rustlib/$ARCH/lib`. FIXME: This step's
+//! `build/$HOST/stage0-sysroot/lib/rustlib/$ARCH/lib`. FIXME: this step's
 //! documentation should be expanded -- the information already here may be
 //! incorrect.
 //!
@@ -135,7 +135,7 @@ use std::cell::{RefCell, Cell};
 use std::collections::{HashSet, HashMap};
 use std::env;
 use std::fs::{self, OpenOptions, File};
-use std::io::{self, Seek, SeekFrom, Write, Read};
+use std::io::{Seek, SeekFrom, Write, Read};
 use std::path::{PathBuf, Path};
 use std::process::{self, Command};
 use std::slice;
@@ -423,7 +423,7 @@ impl Build {
             Command::new(&build.initial_rustc).arg("--version").arg("--verbose"));
         let local_release = local_version_verbose
             .lines().filter(|x| x.starts_with("release:"))
-            .next().unwrap().trim_left_matches("release:").trim();
+            .next().unwrap().trim_start_matches("release:").trim();
         let my_version = channel::CFG_RELEASE_NUM;
         if local_release.split('.').take(2).eq(my_version.split('.').take(2)) {
             build.verbose(&format!("auto-detected local-rebuild {}", local_release));
@@ -504,7 +504,7 @@ impl Build {
         cleared
     }
 
-    /// Get the space-separated set of activated features for the standard
+    /// Gets the space-separated set of activated features for the standard
     /// library.
     fn std_features(&self) -> String {
         let mut features = "panic-unwind".to_string();
@@ -521,7 +521,7 @@ impl Build {
         features
     }
 
-    /// Get the space-separated set of activated features for the compiler.
+    /// Gets the space-separated set of activated features for the compiler.
     fn rustc_features(&self) -> String {
         let mut features = String::new();
         if self.config.jemalloc {
@@ -609,7 +609,7 @@ impl Build {
         self.out.join(&*target).join("crate-docs")
     }
 
-    /// Returns true if no custom `llvm-config` is set for the specified target.
+    /// Returns `true` if no custom `llvm-config` is set for the specified target.
     ///
     /// If no custom `llvm-config` was specified then Rust's llvm will be used.
     fn is_rust_llvm(&self, target: Interned<String>) -> bool {
@@ -831,6 +831,7 @@ impl Build {
                   !target.contains("msvc") &&
                   !target.contains("emscripten") &&
                   !target.contains("wasm32") &&
+                  !target.contains("nvptx") &&
                   !target.contains("fuchsia") {
             Some(self.cc(target))
         } else {
@@ -856,13 +857,13 @@ impl Build {
             .map(|p| &**p)
     }
 
-    /// Returns true if this is a no-std `target`, if defined
+    /// Returns `true` if this is a no-std `target`, if defined
     fn no_std(&self, target: Interned<String>) -> Option<bool> {
         self.config.target_config.get(&target)
             .map(|t| t.no_std)
     }
 
-    /// Returns whether the target will be tested using the `remote-test-client`
+    /// Returns `true` if the target will be tested using the `remote-test-client`
     /// and `remote-test-server` binaries.
     fn remote_tested(&self, target: Interned<String>) -> bool {
         self.qemu_rootfs(target).is_some() || target.contains("android") ||
@@ -1058,7 +1059,7 @@ impl Build {
         self.rust_info.version(self, channel::CFG_RELEASE_NUM)
     }
 
-    /// Return the full commit hash
+    /// Returns the full commit hash.
     fn rust_sha(&self) -> Option<&str> {
         self.rust_info.sha()
     }
@@ -1078,7 +1079,7 @@ impl Build {
         panic!("failed to find version in {}'s Cargo.toml", package)
     }
 
-    /// Returns whether unstable features should be enabled for the compiler
+    /// Returns `true` if unstable features should be enabled for the compiler
     /// we're building.
     fn unstable_features(&self) -> bool {
         match &self.config.channel[..] {
@@ -1263,9 +1264,15 @@ impl Build {
             if !src.exists() {
                 panic!("Error: File \"{}\" not found!", src.display());
             }
-            let mut s = t!(fs::File::open(&src));
-            let mut d = t!(fs::File::create(&dst));
-            io::copy(&mut s, &mut d).expect("failed to copy");
+            let metadata = t!(src.symlink_metadata());
+            if let Err(e) = fs::copy(&src, &dst) {
+                panic!("failed to copy `{}` to `{}`: {}", src.display(),
+                       dst.display(), e)
+            }
+            t!(fs::set_permissions(&dst, metadata.permissions()));
+            let atime = FileTime::from_last_access_time(&metadata);
+            let mtime = FileTime::from_last_modification_time(&metadata);
+            t!(filetime::set_file_times(&dst, atime, mtime));
         }
         chmod(&dst, perms);
     }
@@ -1320,7 +1327,7 @@ impl<'a> Compiler {
         self
     }
 
-    /// Returns whether this is a snapshot compiler for `build`'s configuration
+    /// Returns `true` if this is a snapshot compiler for `build`'s configuration
     pub fn is_snapshot(&self, build: &Build) -> bool {
         self.stage == 0 && self.host == build.build
     }
diff --git a/src/bootstrap/mk/Makefile.in b/src/bootstrap/mk/Makefile.in
index 8ff1456f0f47c..1c27cf3909b1a 100644
--- a/src/bootstrap/mk/Makefile.in
+++ b/src/bootstrap/mk/Makefile.in
@@ -53,7 +53,6 @@ check-aux:
 		src/test/run-fail/pretty \
 		src/test/run-pass-valgrind/pretty \
 		src/test/run-pass-fulldeps/pretty \
-		src/test/run-fail-fulldeps/pretty \
 		$(AUX_ARGS) \
 		$(BOOTSTRAP_ARGS)
 check-bootstrap:
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index cb9c86df55080..f48f9ee752e93 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -36,7 +36,10 @@ impl Step for Llvm {
     const ONLY_HOSTS: bool = true;
 
     fn should_run(run: ShouldRun) -> ShouldRun {
-        run.path("src/llvm").path("src/llvm-emscripten")
+        run.path("src/llvm-project")
+            .path("src/llvm-project/llvm")
+            .path("src/llvm")
+            .path("src/llvm-emscripten")
     }
 
     fn make_run(run: RunConfig) {
@@ -97,7 +100,7 @@ impl Step for Llvm {
         t!(fs::create_dir_all(&out_dir));
 
         // http://llvm.org/docs/CMake.html
-        let root = if self.emscripten { "src/llvm-emscripten" } else { "src/llvm" };
+        let root = if self.emscripten { "src/llvm-emscripten" } else { "src/llvm-project/llvm" };
         let mut cfg = cmake::Config::new(builder.src.join(root));
 
         let profile = match (builder.config.llvm_optimize, builder.config.llvm_release_debuginfo) {
@@ -189,10 +192,10 @@ impl Step for Llvm {
         }
 
         if want_lldb {
-            cfg.define("LLVM_EXTERNAL_CLANG_SOURCE_DIR", builder.src.join("src/tools/clang"));
-            cfg.define("LLVM_EXTERNAL_LLDB_SOURCE_DIR", builder.src.join("src/tools/lldb"));
+            cfg.define("LLVM_ENABLE_PROJECTS", "clang;lldb");
             // For the time being, disable code signing.
             cfg.define("LLDB_CODESIGN_IDENTITY", "");
+            cfg.define("LLDB_NO_DEBUGSERVER", "ON");
         } else {
             // LLDB requires libxml2; but otherwise we want it to be disabled.
             // See https://github.com/rust-lang/rust/pull/50104
@@ -231,6 +234,10 @@ impl Step for Llvm {
             cfg.define("LLVM_VERSION_SUFFIX", suffix);
         }
 
+        if let Some(ref linker) = builder.config.llvm_use_linker {
+            cfg.define("LLVM_USE_LINKER", linker);
+        }
+
         if let Some(ref python) = builder.config.python {
             cfg.define("PYTHON_EXECUTABLE", python);
         }
@@ -358,7 +365,11 @@ fn configure_cmake(builder: &Builder,
     }
 
     cfg.build_arg("-j").build_arg(builder.jobs().to_string());
-    cfg.define("CMAKE_C_FLAGS", builder.cflags(target, GitRepo::Llvm).join(" "));
+    let mut cflags = builder.cflags(target, GitRepo::Llvm).join(" ");
+    if let Some(ref s) = builder.config.llvm_cxxflags {
+        cflags.push_str(&format!(" {}", s));
+    }
+    cfg.define("CMAKE_C_FLAGS", cflags);
     let mut cxxflags = builder.cflags(target, GitRepo::Llvm).join(" ");
     if builder.config.llvm_static_stdcpp &&
         !target.contains("windows") &&
@@ -366,6 +377,9 @@ fn configure_cmake(builder: &Builder,
     {
         cxxflags.push_str(" -static-libstdc++");
     }
+    if let Some(ref s) = builder.config.llvm_cxxflags {
+        cxxflags.push_str(&format!(" {}", s));
+    }
     cfg.define("CMAKE_CXX_FLAGS", cxxflags);
     if let Some(ar) = builder.ar(target) {
         if ar.is_absolute() {
@@ -383,6 +397,12 @@ fn configure_cmake(builder: &Builder,
         }
     }
 
+    if let Some(ref s) = builder.config.llvm_ldflags {
+        cfg.define("CMAKE_SHARED_LINKER_FLAGS", s);
+        cfg.define("CMAKE_MODULE_LINKER_FLAGS", s);
+        cfg.define("CMAKE_EXE_LINKER_FLAGS", s);
+    }
+
     if env::var_os("SCCACHE_ERROR_LOG").is_some() {
         cfg.env("RUST_LOG", "sccache=warn");
     }
@@ -398,7 +418,7 @@ impl Step for Lld {
     const ONLY_HOSTS: bool = true;
 
     fn should_run(run: ShouldRun) -> ShouldRun {
-        run.path("src/tools/lld")
+        run.path("src/llvm-project/lld").path("src/tools/lld")
     }
 
     fn make_run(run: RunConfig) {
@@ -428,7 +448,7 @@ impl Step for Lld {
         let _time = util::timeit(&builder);
         t!(fs::create_dir_all(&out_dir));
 
-        let mut cfg = cmake::Config::new(builder.src.join("src/tools/lld"));
+        let mut cfg = cmake::Config::new(builder.src.join("src/llvm-project/lld"));
         configure_cmake(builder, target, &mut cfg);
 
         // This is an awful, awful hack. Discovered when we migrated to using
diff --git a/src/bootstrap/sanity.rs b/src/bootstrap/sanity.rs
index fe547a6b151c2..ff4fb85bbfad3 100644
--- a/src/bootstrap/sanity.rs
+++ b/src/bootstrap/sanity.rs
@@ -156,7 +156,7 @@ pub fn check(build: &mut Build) {
             panic!("the iOS target is only supported on macOS");
         }
 
-        if target.contains("-none-") {
+        if target.contains("-none-") || target.contains("nvptx") {
             if build.no_std(*target).is_none() {
                 let target = build.config.target_config.entry(target.clone())
                     .or_default();
@@ -165,7 +165,7 @@ pub fn check(build: &mut Build) {
             }
 
             if build.no_std(*target) == Some(false) {
-                panic!("All the *-none-* targets are no-std targets")
+                panic!("All the *-none-* and nvptx* targets are no-std targets")
             }
         }
 
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index 2edc78ebaa94f..a882550f734f4 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -30,9 +30,9 @@ const ADB_TEST_DIR: &str = "/data/tmp/work";
 /// The two modes of the test runner; tests or benchmarks.
 #[derive(Debug, PartialEq, Eq, Hash, Copy, Clone, PartialOrd, Ord)]
 pub enum TestKind {
-    /// Run `cargo test`
+    /// Run `cargo test`.
     Test,
-    /// Run `cargo bench`
+    /// Run `cargo bench`.
     Bench,
 }
 
@@ -848,12 +848,6 @@ host_test!(RunPassFullDeps {
     suite: "run-pass-fulldeps"
 });
 
-host_test!(RunFailFullDeps {
-    path: "src/test/run-fail-fulldeps",
-    mode: "run-fail",
-    suite: "run-fail-fulldeps"
-});
-
 host_test!(Rustdoc {
     path: "src/test/rustdoc",
     mode: "rustdoc",
@@ -888,20 +882,6 @@ test!(RunPassValgrindPretty {
     default: false,
     host: true
 });
-test!(RunPassFullDepsPretty {
-    path: "src/test/run-pass-fulldeps/pretty",
-    mode: "pretty",
-    suite: "run-pass-fulldeps",
-    default: false,
-    host: true
-});
-test!(RunFailFullDepsPretty {
-    path: "src/test/run-fail-fulldeps/pretty",
-    mode: "pretty",
-    suite: "run-fail-fulldeps",
-    default: false,
-    host: true
-});
 
 default_test!(RunMake {
     path: "src/test/run-make",
@@ -1108,9 +1088,7 @@ impl Step for Compiletest {
         };
         let lldb_exe = if builder.config.lldb_enabled && !target.contains("emscripten") {
             // Test against the lldb that was just built.
-            builder.llvm_out(target)
-                .join("bin")
-                .join("lldb")
+            builder.llvm_out(target).join("bin").join("lldb")
         } else {
             PathBuf::from("lldb")
         };
@@ -1127,6 +1105,26 @@ impl Step for Compiletest {
             }
         }
 
+        if let Some(var) = env::var_os("RUSTBUILD_FORCE_CLANG_BASED_TESTS") {
+            match &var.to_string_lossy().to_lowercase()[..] {
+                "1" | "yes" | "on" => {
+                    assert!(builder.config.lldb_enabled,
+                        "RUSTBUILD_FORCE_CLANG_BASED_TESTS needs Clang/LLDB to \
+                         be built.");
+                    let clang_exe = builder.llvm_out(target).join("bin").join("clang");
+                    cmd.arg("--run-clang-based-tests-with").arg(clang_exe);
+                }
+                "0" | "no" | "off" => {
+                    // Nothing to do.
+                }
+                other => {
+                    // Let's make sure typos don't get unnoticed
+                    panic!("Unrecognized option '{}' set in \
+                            RUSTBUILD_FORCE_CLANG_BASED_TESTS", other);
+                }
+            }
+        }
+
         // Get paths from cmd args
         let paths = match &builder.config.cmd {
             Subcommand::Test { ref paths, .. } => &paths[..],
@@ -1290,7 +1288,7 @@ impl Step for DocTest {
         run.never()
     }
 
-    /// Run `rustdoc --test` for all documentation in `src/doc`.
+    /// Runs `rustdoc --test` for all documentation in `src/doc`.
     ///
     /// This will run all tests in our markdown documentation (e.g., the book)
     /// located in `src/doc`. The `rustdoc` that's run is the one that sits next to
@@ -1385,6 +1383,7 @@ test_book!(
     RustdocBook, "src/doc/rustdoc", "rustdoc", default=true;
     RustcBook, "src/doc/rustc", "rustc", default=true;
     RustByExample, "src/doc/rust-by-example", "rust-by-example", default=false;
+    EmbeddedBook, "src/doc/embedded-book", "embedded-book", default=false;
     TheBook, "src/doc/book", "book", default=false;
     UnstableBook, "src/doc/unstable-book", "unstable-book", default=true;
 );
@@ -1409,7 +1408,7 @@ impl Step for ErrorIndex {
         });
     }
 
-    /// Run the error index generator tool to execute the tests located in the error
+    /// Runs the error index generator tool to execute the tests located in the error
     /// index.
     ///
     /// The `error_index_generator` tool lives in `src/tools` and is used to
@@ -1615,7 +1614,7 @@ impl Step for Crate {
         }
     }
 
-    /// Run all unit tests plus documentation tests for a given crate defined
+    /// Runs all unit tests plus documentation tests for a given crate defined
     /// by a `Cargo.toml` (single manifest)
     ///
     /// This is what runs tests for crates like the standard library, compiler, etc.
@@ -1834,7 +1833,7 @@ fn envify(s: &str) -> String {
 /// the standard library and such to the emulator ahead of time. This step
 /// represents this and is a dependency of all test suites.
 ///
-/// Most of the time this is a noop. For some steps such as shipping data to
+/// Most of the time this is a no-op. For some steps such as shipping data to
 /// QEMU we have to build our own tools so we've got conditional dependencies
 /// on those programs as well. Note that the remote test client is built for
 /// the build target (us) and the server is built for the target.
@@ -1905,7 +1904,7 @@ impl Step for Distcheck {
         run.builder.ensure(Distcheck);
     }
 
-    /// Run "distcheck", a 'make check' from a tarball
+    /// Runs "distcheck", a 'make check' from a tarball
     fn run(self, builder: &Builder) {
         builder.info("Distcheck");
         let dir = builder.out.join("tmp").join("distcheck");
@@ -1966,7 +1965,7 @@ impl Step for Bootstrap {
     const DEFAULT: bool = true;
     const ONLY_HOSTS: bool = true;
 
-    /// Test the build system itself
+    /// Tests the build system itself.
     fn run(self, builder: &Builder) {
         let mut cmd = Command::new(&builder.initial_cargo);
         cmd.arg("test")
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 9f6db73e6f713..6383a2ecc7583 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -1,6 +1,5 @@
 use std::fs;
 use std::env;
-use std::iter;
 use std::path::PathBuf;
 use std::process::{Command, exit};
 use std::collections::HashSet;
@@ -41,7 +40,7 @@ impl Step for ToolBuild {
         run.never()
     }
 
-    /// Build a tool in `src/tools`
+    /// Builds a tool in `src/tools`
     ///
     /// This will build the specified tool with the specified `host` compiler in
     /// `stage` into the normal cargo output directory.
@@ -419,25 +418,25 @@ impl Step for Rustdoc {
 
     fn run(self, builder: &Builder) -> PathBuf {
         let target_compiler = builder.compiler(builder.top_stage, self.host);
+        if target_compiler.stage == 0 {
+            if !target_compiler.is_snapshot(builder) {
+                panic!("rustdoc in stage 0 must be snapshot rustdoc");
+            }
+            return builder.initial_rustc.with_file_name(exe("rustdoc", &target_compiler.host));
+        }
         let target = target_compiler.host;
-        let build_compiler = if target_compiler.stage == 0 {
-            builder.compiler(0, builder.config.build)
-        } else if target_compiler.stage >= 2 {
-            // Past stage 2, we consider the compiler to be ABI-compatible and hence capable of
-            // building rustdoc itself.
-            builder.compiler(target_compiler.stage, builder.config.build)
-        } else {
-            // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
-            // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
-            // compilers, which isn't what we want.
-            builder.compiler(target_compiler.stage - 1, builder.config.build)
-        };
-
-        builder.ensure(compile::Rustc { compiler: build_compiler, target });
-        builder.ensure(compile::Rustc {
-            compiler: build_compiler,
-            target: builder.config.build,
-        });
+        // Similar to `compile::Assemble`, build with the previous stage's compiler. Otherwise
+        // we'd have stageN/bin/rustc and stageN/bin/rustdoc be effectively different stage
+        // compilers, which isn't what we want. Rustdoc should be linked in the same way as the
+        // rustc compiler it's paired with, so it must be built with the previous stage compiler.
+        let build_compiler = builder.compiler(target_compiler.stage - 1, builder.config.build);
+
+        // The presence of `target_compiler` ensures that the necessary libraries (codegen backends,
+        // compiler libraries, ...) are built. Rustdoc does not require the presence of any
+        // libraries within sysroot_libdir (i.e., rustlib), though doctests may want it (since
+        // they'll be linked to those libraries). As such, don't explicitly `ensure` any additional
+        // libraries here. The intuition here is that If we've built a compiler, we should be able
+        // to build rustdoc.
 
         let mut cargo = prepare_tool_cargo(
             builder,
@@ -622,7 +621,7 @@ tool_extended!((self, builder),
 );
 
 impl<'a> Builder<'a> {
-    /// Get a `Command` which is ready to run `tool` in `stage` built for
+    /// Gets a `Command` which is ready to run `tool` in `stage` built for
     /// `host`.
     pub fn tool_cmd(&self, tool: Tool) -> Command {
         let mut cmd = Command::new(self.tool_exe(tool));
@@ -666,19 +665,33 @@ impl<'a> Builder<'a> {
 
         // Add the llvm/bin directory to PATH since it contains lots of
         // useful, platform-independent tools
-        if tool.uses_llvm_tools() {
+        if tool.uses_llvm_tools() && !self.config.dry_run {
+            let mut additional_paths = vec![];
+
             if let Some(llvm_bin_path) = self.llvm_bin_path() {
-                if host.contains("windows") {
-                    // On Windows, PATH and the dynamic library path are the same,
-                    // so we just add the LLVM bin path to lib_path
-                    lib_paths.push(llvm_bin_path);
-                } else {
-                    let old_path = env::var_os("PATH").unwrap_or_default();
-                    let new_path = env::join_paths(iter::once(llvm_bin_path)
-                            .chain(env::split_paths(&old_path)))
-                        .expect("Could not add LLVM bin path to PATH");
-                    cmd.env("PATH", new_path);
-                }
+                additional_paths.push(llvm_bin_path);
+            }
+
+            // If LLD is available, add that too.
+            if self.config.lld_enabled {
+                let lld_install_root = self.ensure(native::Lld {
+                    target: self.config.build,
+                });
+
+                let lld_bin_path = lld_install_root.join("bin");
+                additional_paths.push(lld_bin_path);
+            }
+
+            if host.contains("windows") {
+                // On Windows, PATH and the dynamic library path are the same,
+                // so we just add the LLVM bin path to lib_path
+                lib_paths.extend(additional_paths);
+            } else {
+                let old_path = env::var_os("PATH").unwrap_or_default();
+                let new_path = env::join_paths(additional_paths.into_iter()
+                        .chain(env::split_paths(&old_path)))
+                    .expect("Could not add LLVM bin path to PATH");
+                cmd.env("PATH", new_path);
             }
         }
 
@@ -686,7 +699,7 @@ impl<'a> Builder<'a> {
     }
 
     fn llvm_bin_path(&self) -> Option<PathBuf> {
-        if self.config.llvm_enabled && !self.config.dry_run {
+        if self.config.llvm_enabled {
             let llvm_config = self.ensure(native::Llvm {
                 target: self.config.build,
                 emscripten: false,
diff --git a/src/bootstrap/util.rs b/src/bootstrap/util.rs
index 2880f1a084be0..29aa98971fb56 100644
--- a/src/bootstrap/util.rs
+++ b/src/bootstrap/util.rs
@@ -33,7 +33,7 @@ pub fn exe(name: &str, target: &str) -> String {
     }
 }
 
-/// Returns whether the file name given looks like a dynamic library.
+/// Returns `true` if the file name given looks like a dynamic library.
 pub fn is_dylib(name: &str) -> bool {
     name.ends_with(".dylib") || name.ends_with(".so") || name.ends_with(".dll")
 }
@@ -70,7 +70,11 @@ pub fn dylib_path_var() -> &'static str {
 /// Parses the `dylib_path_var()` environment variable, returning a list of
 /// paths that are members of this lookup path.
 pub fn dylib_path() -> Vec<PathBuf> {
-    env::split_paths(&env::var_os(dylib_path_var()).unwrap_or_default()).collect()
+    let var = match env::var_os(dylib_path_var()) {
+        Some(v) => v,
+        None => return vec![],
+    };
+    env::split_paths(&var).collect()
 }
 
 /// `push` all components to `buf`. On windows, append `.exe` to the last component.
diff --git a/src/build_helper/Cargo.toml b/src/build_helper/Cargo.toml
index 01d704f816bbc..04c7820b45665 100644
--- a/src/build_helper/Cargo.toml
+++ b/src/build_helper/Cargo.toml
@@ -2,6 +2,7 @@
 name = "build_helper"
 version = "0.1.0"
 authors = ["The Rust Project Developers"]
+edition = "2018"
 
 [lib]
 name = "build_helper"
diff --git a/src/build_helper/lib.rs b/src/build_helper/lib.rs
index 5a704e557751d..bd99dc118e66a 100644
--- a/src/build_helper/lib.rs
+++ b/src/build_helper/lib.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 use std::fs::File;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
@@ -23,6 +25,25 @@ macro_rules! t {
     };
 }
 
+// Because Cargo adds the compiler's dylib path to our library search path, llvm-config may
+// break: the dylib path for the compiler, as of this writing, contains a copy of the LLVM
+// shared library, which means that when our freshly built llvm-config goes to load it's
+// associated LLVM, it actually loads the compiler's LLVM. In particular when building the first
+// compiler (i.e., in stage 0) that's a problem, as the compiler's LLVM is likely different from
+// the one we want to use. As such, we restore the environment to what bootstrap saw. This isn't
+// perfect -- we might actually want to see something from Cargo's added library paths -- but
+// for now it works.
+pub fn restore_library_path() {
+    println!("cargo:rerun-if-env-changed=REAL_LIBRARY_PATH_VAR");
+    println!("cargo:rerun-if-env-changed=REAL_LIBRARY_PATH");
+    let key = env::var_os("REAL_LIBRARY_PATH_VAR").expect("REAL_LIBRARY_PATH_VAR");
+    if let Some(env) = env::var_os("REAL_LIBRARY_PATH") {
+        env::set_var(&key, &env);
+    } else {
+        env::remove_var(&key);
+    }
+}
+
 pub fn run(cmd: &mut Command) {
     println!("running: {:?}", cmd);
     run_silent(cmd);
@@ -142,7 +163,7 @@ pub fn mtime(path: &Path) -> SystemTime {
         .unwrap_or(UNIX_EPOCH)
 }
 
-/// Returns whether `dst` is up to date given that the file or files in `src`
+/// Returns `true` if `dst` is up to date given that the file or files in `src`
 /// are used to generate it.
 ///
 /// Uses last-modified time checks to verify this.
@@ -169,12 +190,12 @@ pub struct NativeLibBoilerplate {
 }
 
 impl NativeLibBoilerplate {
-    /// On OSX we don't want to ship the exact filename that compiler-rt builds.
+    /// On macOS we don't want to ship the exact filename that compiler-rt builds.
     /// This conflicts with the system and ours is likely a wildly different
     /// version, so they can't be substituted.
     ///
     /// As a result, we rename it here but we need to also use
-    /// `install_name_tool` on OSX to rename the commands listed inside of it to
+    /// `install_name_tool` on macOS to rename the commands listed inside of it to
     /// ensure it's linked against correctly.
     pub fn fixup_sanitizer_lib_name(&self, sanitizer_name: &str) {
         if env::var("TARGET").unwrap() != "x86_64-apple-darwin" {
diff --git a/src/ci/docker/README.md b/src/ci/docker/README.md
index 8d4dbc399986f..34320ab4411e2 100644
--- a/src/ci/docker/README.md
+++ b/src/ci/docker/README.md
@@ -131,13 +131,15 @@ $category > $option = $value -- $comment
 For targets: `arm-unknown-linux-gnueabi`
 
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
+- Path and misc options > Patches origin = Bundled, then local
+- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = arm
 - Target options > Architecture level = armv6 -- (+)
 - Target options > Floating point = software (no FPU) -- (\*)
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 3.2.72 -- Precise kernel
-- C-library > glibc version = 2.14.1
-- C compiler > gcc version = 4.9.3
+- C-library > glibc version = 2.16.0
+- C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 ### `arm-linux-gnueabihf.config`
@@ -145,6 +147,8 @@ For targets: `arm-unknown-linux-gnueabi`
 For targets: `arm-unknown-linux-gnueabihf`
 
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
+- Path and misc options > Patches origin = Bundled, then local
+- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = arm
 - Target options > Architecture level = armv6 -- (+)
 - Target options > Use specific FPU = vfp -- (+)
@@ -152,8 +156,8 @@ For targets: `arm-unknown-linux-gnueabihf`
 - Target options > Default instruction set mode = arm -- (+)
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 3.2.72 -- Precise kernel
-- C-library > glibc version = 2.14.1
-- C compiler > gcc version = 4.9.3
+- C-library > glibc version = 2.16.0
+- C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 ### `armv7-linux-gnueabihf.config`
@@ -161,6 +165,8 @@ For targets: `arm-unknown-linux-gnueabihf`
 For targets: `armv7-unknown-linux-gnueabihf`
 
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
+- Path and misc options > Patches origin = Bundled, then local
+- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = arm
 - Target options > Suffix to the arch-part = v7
 - Target options > Architecture level = armv7-a -- (+)
@@ -169,8 +175,8 @@ For targets: `armv7-unknown-linux-gnueabihf`
 - Target options > Default instruction set mode = thumb -- (\*)
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 3.2.72 -- Precise kernel
-- C-library > glibc version = 2.14.1
-- C compiler > gcc version = 4.9.3
+- C-library > glibc version = 2.16.0
+- C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 (\*) These options have been selected to match the configuration of the arm
@@ -204,7 +210,7 @@ For targets: `powerpc-unknown-linux-gnu`
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
 - C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
-- C compiler > gcc version = 4.9.3
+- C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 ### `powerpc64-linux-gnu.config`
@@ -221,7 +227,7 @@ For targets: `powerpc64-unknown-linux-gnu`
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
 - C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
-- C compiler > gcc version = 4.9.3
+- C compiler > gcc version = 5.2.0
 - C compiler > C++ = ENABLE -- to cross compile LLVM
 
 (+) These CPU options match the configuration of the toolchains in RHEL6.
@@ -232,12 +238,12 @@ For targets: `s390x-unknown-linux-gnu`
 
 - Path and misc options > Prefix directory = /x-tools/${CT\_TARGET}
 - Path and misc options > Patches origin = Bundled, then local
-- Path and misc options > Local patch directory = /build/patches
+- Path and misc options > Local patch directory = /tmp/patches
 - Target options > Target Architecture = s390
 - Target options > Bitness = 64-bit
 - Operating System > Target OS = linux
 - Operating System > Linux kernel version = 2.6.32.68 -- ~RHEL6 kernel
 - C-library > glibc version = 2.12.2 -- ~RHEL6 glibc
-- C compiler > gcc version = 4.9.3
+- C compiler > gcc version = 5.2.0
 - C compiler > gcc extra config = --with-arch=z10 -- LLVM's minimum support
 - C compiler > C++ = ENABLE -- to cross compile LLVM
diff --git a/src/ci/docker/dist-arm-linux/Dockerfile b/src/ci/docker/dist-arm-linux/Dockerfile
index 6ddc5c1e04ae3..48851ae232c99 100644
--- a/src/ci/docker/dist-arm-linux/Dockerfile
+++ b/src/ci/docker/dist-arm-linux/Dockerfile
@@ -16,6 +16,7 @@ RUN sh /scripts/rustbuild-setup.sh
 USER rustbuild
 WORKDIR /tmp
 
+COPY dist-arm-linux/patches/ /tmp/patches/
 COPY dist-arm-linux/arm-linux-gnueabi.config dist-arm-linux/build-toolchains.sh /tmp/
 RUN ./build-toolchains.sh
 
diff --git a/src/ci/docker/dist-arm-linux/arm-linux-gnueabi.config b/src/ci/docker/dist-arm-linux/arm-linux-gnueabi.config
index f73ad069550e1..4185112d8be90 100644
--- a/src/ci/docker/dist-arm-linux/arm-linux-gnueabi.config
+++ b/src/ci/docker/dist-arm-linux/arm-linux-gnueabi.config
@@ -3,6 +3,7 @@
 # Crosstool-NG Configuration
 #
 CT_CONFIGURE_has_make381=y
+CT_CONFIGURE_has_xz=y
 CT_MODULES=y
 
 #
@@ -44,14 +45,16 @@ CT_CONNECT_TIMEOUT=10
 # CT_FORCE_EXTRACT is not set
 CT_OVERIDE_CONFIG_GUESS_SUB=y
 # CT_ONLY_EXTRACT is not set
-CT_PATCH_BUNDLED=y
+# CT_PATCH_BUNDLED is not set
 # CT_PATCH_LOCAL is not set
-# CT_PATCH_BUNDLED_LOCAL is not set
+CT_PATCH_BUNDLED_LOCAL=y
 # CT_PATCH_LOCAL_BUNDLED is not set
 # CT_PATCH_BUNDLED_FALLBACK_LOCAL is not set
 # CT_PATCH_LOCAL_FALLBACK_BUNDLED is not set
 # CT_PATCH_NONE is not set
-CT_PATCH_ORDER="bundled"
+CT_PATCH_ORDER="bundled,local"
+CT_PATCH_USE_LOCAL=y
+CT_LOCAL_PATCH_DIR="/tmp/patches"
 
 #
 # Build behavior
@@ -391,8 +394,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -407,8 +410,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -420,7 +424,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -492,7 +496,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -500,7 +503,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -526,15 +528,13 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
+# CT_CLOOG_V_0_18_4 is not set
 # CT_CLOOG_V_0_18_1 is not set
 # CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-arm-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch b/src/ci/docker/dist-arm-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
new file mode 100644
index 0000000000000..871d5225c0f71
--- /dev/null
+++ b/src/ci/docker/dist-arm-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
@@ -0,0 +1,48 @@
+commit bdb24c2851fd5f0ad9b82d7ea1db911d334b02d2
+Author: Joseph Myers <joseph@codesourcery.com>
+Date:   Tue May 20 21:27:13 2014 +0000
+
+    Fix ARM build with GCC trunk.
+    
+    sysdeps/unix/sysv/linux/arm/unwind-resume.c and
+    sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c have static
+    variables that are written in C code but only read from toplevel asms.
+    Current GCC trunk now optimizes away such apparently write-only static
+    variables, so causing a build failure.  This patch marks those
+    variables with __attribute_used__ to avoid that optimization.
+    
+    Tested that this fixes the build for ARM.
+    
+            * sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c
+            (libgcc_s_resume): Use __attribute_used__.
+            * sysdeps/unix/sysv/linux/arm/unwind-resume.c (libgcc_s_resume):
+            Likewise.
+
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+index 29e2c2b00b04..e848bfeffdcb 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+@@ -22,7 +22,8 @@
+ #include <pthreadP.h>
+ 
+ static void *libgcc_s_handle;
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+index 285b99b5ed0d..48d00fc83641 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+@@ -20,7 +20,8 @@
+ #include <stdio.h>
+ #include <unwind.h>
+ 
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ 
diff --git a/src/ci/docker/dist-armhf-linux/Dockerfile b/src/ci/docker/dist-armhf-linux/Dockerfile
index e4d4b2feeec40..d1dd9faaa1035 100644
--- a/src/ci/docker/dist-armhf-linux/Dockerfile
+++ b/src/ci/docker/dist-armhf-linux/Dockerfile
@@ -16,6 +16,7 @@ RUN sh /scripts/rustbuild-setup.sh
 USER rustbuild
 WORKDIR /tmp
 
+COPY dist-armhf-linux/patches/ /tmp/patches/
 COPY dist-armhf-linux/arm-linux-gnueabihf.config dist-armhf-linux/build-toolchains.sh /tmp/
 RUN ./build-toolchains.sh
 
diff --git a/src/ci/docker/dist-armhf-linux/arm-linux-gnueabihf.config b/src/ci/docker/dist-armhf-linux/arm-linux-gnueabihf.config
index 1feeef1555749..bebbcd1670a5e 100644
--- a/src/ci/docker/dist-armhf-linux/arm-linux-gnueabihf.config
+++ b/src/ci/docker/dist-armhf-linux/arm-linux-gnueabihf.config
@@ -3,6 +3,7 @@
 # Crosstool-NG Configuration
 #
 CT_CONFIGURE_has_make381=y
+CT_CONFIGURE_has_xz=y
 CT_MODULES=y
 
 #
@@ -44,14 +45,16 @@ CT_CONNECT_TIMEOUT=10
 # CT_FORCE_EXTRACT is not set
 CT_OVERIDE_CONFIG_GUESS_SUB=y
 # CT_ONLY_EXTRACT is not set
-CT_PATCH_BUNDLED=y
+# CT_PATCH_BUNDLED is not set
 # CT_PATCH_LOCAL is not set
-# CT_PATCH_BUNDLED_LOCAL is not set
+CT_PATCH_BUNDLED_LOCAL=y
 # CT_PATCH_LOCAL_BUNDLED is not set
 # CT_PATCH_BUNDLED_FALLBACK_LOCAL is not set
 # CT_PATCH_LOCAL_FALLBACK_BUNDLED is not set
 # CT_PATCH_NONE is not set
-CT_PATCH_ORDER="bundled"
+CT_PATCH_ORDER="bundled,local"
+CT_PATCH_USE_LOCAL=y
+CT_LOCAL_PATCH_DIR="/tmp/patches"
 
 #
 # Build behavior
@@ -392,8 +395,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -408,8 +411,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -421,7 +425,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -493,7 +497,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -501,7 +504,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -527,15 +529,13 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
+# CT_CLOOG_V_0_18_4 is not set
 # CT_CLOOG_V_0_18_1 is not set
 # CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-armhf-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch b/src/ci/docker/dist-armhf-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
new file mode 100644
index 0000000000000..871d5225c0f71
--- /dev/null
+++ b/src/ci/docker/dist-armhf-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
@@ -0,0 +1,48 @@
+commit bdb24c2851fd5f0ad9b82d7ea1db911d334b02d2
+Author: Joseph Myers <joseph@codesourcery.com>
+Date:   Tue May 20 21:27:13 2014 +0000
+
+    Fix ARM build with GCC trunk.
+    
+    sysdeps/unix/sysv/linux/arm/unwind-resume.c and
+    sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c have static
+    variables that are written in C code but only read from toplevel asms.
+    Current GCC trunk now optimizes away such apparently write-only static
+    variables, so causing a build failure.  This patch marks those
+    variables with __attribute_used__ to avoid that optimization.
+    
+    Tested that this fixes the build for ARM.
+    
+            * sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c
+            (libgcc_s_resume): Use __attribute_used__.
+            * sysdeps/unix/sysv/linux/arm/unwind-resume.c (libgcc_s_resume):
+            Likewise.
+
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+index 29e2c2b00b04..e848bfeffdcb 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+@@ -22,7 +22,8 @@
+ #include <pthreadP.h>
+ 
+ static void *libgcc_s_handle;
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+index 285b99b5ed0d..48d00fc83641 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+@@ -20,7 +20,8 @@
+ #include <stdio.h>
+ #include <unwind.h>
+ 
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ 
diff --git a/src/ci/docker/dist-armv7-linux/Dockerfile b/src/ci/docker/dist-armv7-linux/Dockerfile
index 99fe7bd7b8f78..170b8134d3edc 100644
--- a/src/ci/docker/dist-armv7-linux/Dockerfile
+++ b/src/ci/docker/dist-armv7-linux/Dockerfile
@@ -16,6 +16,7 @@ RUN sh /scripts/rustbuild-setup.sh
 USER rustbuild
 WORKDIR /tmp
 
+COPY dist-armv7-linux/patches/ /tmp/patches/
 COPY dist-armv7-linux/build-toolchains.sh dist-armv7-linux/armv7-linux-gnueabihf.config /tmp/
 RUN ./build-toolchains.sh
 
diff --git a/src/ci/docker/dist-armv7-linux/armv7-linux-gnueabihf.config b/src/ci/docker/dist-armv7-linux/armv7-linux-gnueabihf.config
index 79d6c77c41152..5cccfd8444d35 100644
--- a/src/ci/docker/dist-armv7-linux/armv7-linux-gnueabihf.config
+++ b/src/ci/docker/dist-armv7-linux/armv7-linux-gnueabihf.config
@@ -3,6 +3,7 @@
 # Crosstool-NG Configuration
 #
 CT_CONFIGURE_has_make381=y
+CT_CONFIGURE_has_xz=y
 CT_MODULES=y
 
 #
@@ -44,14 +45,16 @@ CT_CONNECT_TIMEOUT=10
 # CT_FORCE_EXTRACT is not set
 CT_OVERIDE_CONFIG_GUESS_SUB=y
 # CT_ONLY_EXTRACT is not set
-CT_PATCH_BUNDLED=y
+# CT_PATCH_BUNDLED is not set
 # CT_PATCH_LOCAL is not set
-# CT_PATCH_BUNDLED_LOCAL is not set
+CT_PATCH_BUNDLED_LOCAL=y
 # CT_PATCH_LOCAL_BUNDLED is not set
 # CT_PATCH_BUNDLED_FALLBACK_LOCAL is not set
 # CT_PATCH_LOCAL_FALLBACK_BUNDLED is not set
 # CT_PATCH_NONE is not set
-CT_PATCH_ORDER="bundled"
+CT_PATCH_ORDER="bundled,local"
+CT_PATCH_USE_LOCAL=y
+CT_LOCAL_PATCH_DIR="/tmp/patches"
 
 #
 # Build behavior
@@ -155,12 +158,6 @@ CT_ARCH_EXCLUSIVE_WITH_CPU=y
 # CT_ARCH_FLOAT_AUTO is not set
 # CT_ARCH_FLOAT_SOFTFP is not set
 CT_ARCH_FLOAT="hard"
-# CT_ARCH_ALPHA_EV4 is not set
-# CT_ARCH_ALPHA_EV45 is not set
-# CT_ARCH_ALPHA_EV5 is not set
-# CT_ARCH_ALPHA_EV56 is not set
-# CT_ARCH_ALPHA_EV6 is not set
-# CT_ARCH_ALPHA_EV67 is not set
 
 #
 # arm other options
@@ -311,8 +308,6 @@ CT_LIBC="glibc"
 CT_LIBC_VERSION="2.16.0"
 CT_LIBC_glibc=y
 # CT_LIBC_musl is not set
-# CT_LIBC_newlib is not set
-# CT_LIBC_none is not set
 # CT_LIBC_uClibc is not set
 CT_LIBC_avr_libc_AVAILABLE=y
 CT_LIBC_glibc_AVAILABLE=y
@@ -400,8 +395,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -416,8 +411,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -429,7 +425,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -501,7 +497,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -509,7 +504,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -535,15 +529,13 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
+# CT_CLOOG_V_0_18_4 is not set
 # CT_CLOOG_V_0_18_1 is not set
 # CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-armv7-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch b/src/ci/docker/dist-armv7-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
new file mode 100644
index 0000000000000..871d5225c0f71
--- /dev/null
+++ b/src/ci/docker/dist-armv7-linux/patches/glibc/ports-2.16.0/001-arm-libgcc_s_resume-used.patch
@@ -0,0 +1,48 @@
+commit bdb24c2851fd5f0ad9b82d7ea1db911d334b02d2
+Author: Joseph Myers <joseph@codesourcery.com>
+Date:   Tue May 20 21:27:13 2014 +0000
+
+    Fix ARM build with GCC trunk.
+    
+    sysdeps/unix/sysv/linux/arm/unwind-resume.c and
+    sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c have static
+    variables that are written in C code but only read from toplevel asms.
+    Current GCC trunk now optimizes away such apparently write-only static
+    variables, so causing a build failure.  This patch marks those
+    variables with __attribute_used__ to avoid that optimization.
+    
+    Tested that this fixes the build for ARM.
+    
+            * sysdeps/unix/sysv/linux/arm/unwind-forcedunwind.c
+            (libgcc_s_resume): Use __attribute_used__.
+            * sysdeps/unix/sysv/linux/arm/unwind-resume.c (libgcc_s_resume):
+            Likewise.
+
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+index 29e2c2b00b04..e848bfeffdcb 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c
+@@ -22,7 +22,8 @@
+ #include <pthreadP.h>
+ 
+ static void *libgcc_s_handle;
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
+diff --git a/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c b/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+index 285b99b5ed0d..48d00fc83641 100644
+--- a/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
++++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c
+@@ -20,7 +20,8 @@
+ #include <stdio.h>
+ #include <unwind.h>
+ 
+-static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
++static void (*libgcc_s_resume) (struct _Unwind_Exception *exc)
++  __attribute_used__;
+ static _Unwind_Reason_Code (*libgcc_s_personality)
+   (_Unwind_State, struct _Unwind_Exception *, struct _Unwind_Context *);
+ 
diff --git a/src/ci/docker/dist-powerpc-linux/patches/glibc/2.12.2/002-newer-gcc.patch b/src/ci/docker/dist-powerpc-linux/patches/glibc/2.12.2/002-newer-gcc.patch
new file mode 100644
index 0000000000000..a96b4882c2d57
--- /dev/null
+++ b/src/ci/docker/dist-powerpc-linux/patches/glibc/2.12.2/002-newer-gcc.patch
@@ -0,0 +1,26 @@
+diff --git a/configure b/configure
+index b6752d147c6b..6089a3403410 100755
+--- a/configure
++++ b/configure
+@@ -5079,7 +5079,7 @@ $as_echo_n "checking version of $CC... " >&6; }
+   ac_prog_version=`$CC -v 2>&1 | sed -n 's/^.*version \([egcygnustpi-]*[0-9.]*\).*$/\1/p'`
+   case $ac_prog_version in
+     '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
+-    3.4* | 4.[0-9]* )
++    3.4* | [4-9].* )
+        ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
+     *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
+ 
+diff --git a/configure.in b/configure.in
+index 56849dfc489a..09677eb3d0c1 100644
+--- a/configure.in
++++ b/configure.in
+@@ -960,7 +960,7 @@ fi
+ # These programs are version sensitive.
+ AC_CHECK_TOOL_PREFIX
+ AC_CHECK_PROG_VER(CC, ${ac_tool_prefix}gcc ${ac_tool_prefix}cc, -v,
+-  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | 4.[0-9]* ],
++  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | [4-9].* ],
+   critic_missing="$critic_missing gcc")
+ AC_CHECK_PROG_VER(MAKE, gnumake gmake make, --version,
+   [GNU Make[^0-9]*\([0-9][0-9.]*\)],
diff --git a/src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config b/src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config
index 984a0a0304e47..7df41da2bf76e 100644
--- a/src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config
+++ b/src/ci/docker/dist-powerpc-linux/powerpc-linux-gnu.config
@@ -359,8 +359,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -375,8 +375,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -388,7 +389,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -460,7 +461,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -468,7 +468,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -494,15 +493,13 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
+# CT_CLOOG_V_0_18_4 is not set
 # CT_CLOOG_V_0_18_1 is not set
 # CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-powerpc64-linux/patches/glibc/2.12.2/003-newer-gcc.patch b/src/ci/docker/dist-powerpc64-linux/patches/glibc/2.12.2/003-newer-gcc.patch
new file mode 100644
index 0000000000000..a96b4882c2d57
--- /dev/null
+++ b/src/ci/docker/dist-powerpc64-linux/patches/glibc/2.12.2/003-newer-gcc.patch
@@ -0,0 +1,26 @@
+diff --git a/configure b/configure
+index b6752d147c6b..6089a3403410 100755
+--- a/configure
++++ b/configure
+@@ -5079,7 +5079,7 @@ $as_echo_n "checking version of $CC... " >&6; }
+   ac_prog_version=`$CC -v 2>&1 | sed -n 's/^.*version \([egcygnustpi-]*[0-9.]*\).*$/\1/p'`
+   case $ac_prog_version in
+     '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
+-    3.4* | 4.[0-9]* )
++    3.4* | [4-9].* )
+        ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
+     *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
+ 
+diff --git a/configure.in b/configure.in
+index 56849dfc489a..09677eb3d0c1 100644
+--- a/configure.in
++++ b/configure.in
+@@ -960,7 +960,7 @@ fi
+ # These programs are version sensitive.
+ AC_CHECK_TOOL_PREFIX
+ AC_CHECK_PROG_VER(CC, ${ac_tool_prefix}gcc ${ac_tool_prefix}cc, -v,
+-  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | 4.[0-9]* ],
++  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | [4-9].* ],
+   critic_missing="$critic_missing gcc")
+ AC_CHECK_PROG_VER(MAKE, gnumake gmake make, --version,
+   [GNU Make[^0-9]*\([0-9][0-9.]*\)],
diff --git a/src/ci/docker/dist-powerpc64-linux/powerpc64-linux-gnu.config b/src/ci/docker/dist-powerpc64-linux/powerpc64-linux-gnu.config
index c2d02ee85cf25..4aab4f4fd4445 100644
--- a/src/ci/docker/dist-powerpc64-linux/powerpc64-linux-gnu.config
+++ b/src/ci/docker/dist-powerpc64-linux/powerpc64-linux-gnu.config
@@ -359,8 +359,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -375,8 +375,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -388,7 +389,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -460,7 +461,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -468,7 +468,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -494,15 +493,10 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
-# CT_CLOOG_V_0_18_1 is not set
-# CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-s390x-linux/patches/glibc/2.12.2/002-newer-gcc.patch b/src/ci/docker/dist-s390x-linux/patches/glibc/2.12.2/002-newer-gcc.patch
new file mode 100644
index 0000000000000..a96b4882c2d57
--- /dev/null
+++ b/src/ci/docker/dist-s390x-linux/patches/glibc/2.12.2/002-newer-gcc.patch
@@ -0,0 +1,26 @@
+diff --git a/configure b/configure
+index b6752d147c6b..6089a3403410 100755
+--- a/configure
++++ b/configure
+@@ -5079,7 +5079,7 @@ $as_echo_n "checking version of $CC... " >&6; }
+   ac_prog_version=`$CC -v 2>&1 | sed -n 's/^.*version \([egcygnustpi-]*[0-9.]*\).*$/\1/p'`
+   case $ac_prog_version in
+     '') ac_prog_version="v. ?.??, bad"; ac_verc_fail=yes;;
+-    3.4* | 4.[0-9]* )
++    3.4* | [4-9].* )
+        ac_prog_version="$ac_prog_version, ok"; ac_verc_fail=no;;
+     *) ac_prog_version="$ac_prog_version, bad"; ac_verc_fail=yes;;
+ 
+diff --git a/configure.in b/configure.in
+index 56849dfc489a..09677eb3d0c1 100644
+--- a/configure.in
++++ b/configure.in
+@@ -960,7 +960,7 @@ fi
+ # These programs are version sensitive.
+ AC_CHECK_TOOL_PREFIX
+ AC_CHECK_PROG_VER(CC, ${ac_tool_prefix}gcc ${ac_tool_prefix}cc, -v,
+-  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | 4.[0-9]* ],
++  [version \([egcygnustpi-]*[0-9.]*\)], [3.4* | [4-9].* ],
+   critic_missing="$critic_missing gcc")
+ AC_CHECK_PROG_VER(MAKE, gnumake gmake make, --version,
+   [GNU Make[^0-9]*\([0-9][0-9.]*\)],
diff --git a/src/ci/docker/dist-s390x-linux/s390x-linux-gnu.config b/src/ci/docker/dist-s390x-linux/s390x-linux-gnu.config
index fa5e4510987f1..cd1c41b02e312 100644
--- a/src/ci/docker/dist-s390x-linux/s390x-linux-gnu.config
+++ b/src/ci/docker/dist-s390x-linux/s390x-linux-gnu.config
@@ -339,8 +339,8 @@ CT_CC_CORE_PASS_1_NEEDED=y
 CT_CC_CORE_PASS_2_NEEDED=y
 CT_CC_gcc=y
 # CT_CC_GCC_SHOW_LINARO is not set
-# CT_CC_GCC_V_5_2_0 is not set
-CT_CC_GCC_V_4_9_3=y
+CT_CC_GCC_V_5_2_0=y
+# CT_CC_GCC_V_4_9_3 is not set
 # CT_CC_GCC_V_4_8_5 is not set
 # CT_CC_GCC_V_4_7_4 is not set
 # CT_CC_GCC_V_4_6_4 is not set
@@ -355,8 +355,9 @@ CT_CC_GCC_4_5_or_later=y
 CT_CC_GCC_4_6_or_later=y
 CT_CC_GCC_4_7_or_later=y
 CT_CC_GCC_4_8_or_later=y
-CT_CC_GCC_4_9=y
 CT_CC_GCC_4_9_or_later=y
+CT_CC_GCC_5=y
+CT_CC_GCC_5_or_later=y
 CT_CC_GCC_HAS_GRAPHITE=y
 CT_CC_GCC_USE_GRAPHITE=y
 CT_CC_GCC_HAS_LTO=y
@@ -368,7 +369,7 @@ CT_CC_GCC_USE_GMP_MPFR=y
 CT_CC_GCC_USE_MPC=y
 CT_CC_GCC_HAS_LIBQUADMATH=y
 CT_CC_GCC_HAS_LIBSANITIZER=y
-CT_CC_GCC_VERSION="4.9.3"
+CT_CC_GCC_VERSION="5.2.0"
 # CT_CC_LANG_FORTRAN is not set
 CT_CC_GCC_ENABLE_CXX_FLAGS=""
 CT_CC_GCC_CORE_EXTRA_CONFIG_ARRAY=""
@@ -440,7 +441,6 @@ CT_GETTEXT_NEEDED=y
 CT_GMP_NEEDED=y
 CT_MPFR_NEEDED=y
 CT_ISL_NEEDED=y
-CT_CLOOG_NEEDED=y
 CT_MPC_NEEDED=y
 CT_COMPLIBS=y
 CT_LIBICONV=y
@@ -448,7 +448,6 @@ CT_GETTEXT=y
 CT_GMP=y
 CT_MPFR=y
 CT_ISL=y
-CT_CLOOG=y
 CT_MPC=y
 CT_LIBICONV_V_1_14=y
 CT_LIBICONV_VERSION="1.14"
@@ -474,15 +473,13 @@ CT_MPFR_V_3_1_3=y
 # CT_MPFR_V_2_4_0 is not set
 CT_MPFR_VERSION="3.1.3"
 CT_ISL_V_0_14=y
+# CT_ISL_V_0_12_2 is not set
 CT_ISL_V_0_14_or_later=y
 CT_ISL_V_0_12_or_later=y
 CT_ISL_VERSION="0.14"
-CT_CLOOG_V_0_18_4=y
+# CT_CLOOG_V_0_18_4 is not set
 # CT_CLOOG_V_0_18_1 is not set
 # CT_CLOOG_V_0_18_0 is not set
-CT_CLOOG_VERSION="0.18.4"
-CT_CLOOG_0_18_4_or_later=y
-CT_CLOOG_0_18_or_later=y
 CT_MPC_V_1_0_3=y
 # CT_MPC_V_1_0_2 is not set
 # CT_MPC_V_1_0_1 is not set
diff --git a/src/ci/docker/dist-various-1/Dockerfile b/src/ci/docker/dist-various-1/Dockerfile
index 76cdd367987b2..f80293b182e97 100644
--- a/src/ci/docker/dist-various-1/Dockerfile
+++ b/src/ci/docker/dist-various-1/Dockerfile
@@ -112,17 +112,23 @@ ENV TARGETS=$TARGETS,thumbv7em-none-eabihf
 ENV TARGETS=$TARGETS,thumbv8m.main-none-eabi
 ENV TARGETS=$TARGETS,riscv32imc-unknown-none-elf
 ENV TARGETS=$TARGETS,riscv32imac-unknown-none-elf
+ENV TARGETS=$TARGETS,riscv64imac-unknown-none-elf
+ENV TARGETS=$TARGETS,riscv64gc-unknown-none-elf
 ENV TARGETS=$TARGETS,armebv7r-none-eabi
 ENV TARGETS=$TARGETS,armebv7r-none-eabihf
 ENV TARGETS=$TARGETS,armv7r-none-eabi
 ENV TARGETS=$TARGETS,armv7r-none-eabihf
+ENV TARGETS=$TARGETS,thumbv7neon-unknown-linux-gnueabihf
 
 ENV CC_mipsel_unknown_linux_musl=mipsel-openwrt-linux-gcc \
     CC_mips_unknown_linux_musl=mips-openwrt-linux-gcc \
     CC_sparc64_unknown_linux_gnu=sparc64-linux-gnu-gcc \
     CC_x86_64_unknown_redox=x86_64-unknown-redox-gcc \
-    CC_armebv7r_none_eabi=arm-none-eabi-gcc
-
+    CC_armebv7r_none_eabi=arm-none-eabi-gcc \
+    CC_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-gcc \
+    AR_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-ar \
+    CXX_thumbv7neon_unknown_linux_gnueabihf=arm-linux-gnueabihf-g++
+    
 ENV RUST_CONFIGURE_ARGS \
       --musl-root-armv5te=/musl-armv5te \
       --musl-root-arm=/musl-arm \
diff --git a/src/ci/docker/dist-various-1/install-x86_64-redox.sh b/src/ci/docker/dist-various-1/install-x86_64-redox.sh
index 29222ff60f2a0..c39be14941c90 100755
--- a/src/ci/docker/dist-various-1/install-x86_64-redox.sh
+++ b/src/ci/docker/dist-various-1/install-x86_64-redox.sh
@@ -6,7 +6,7 @@ set -ex
 apt-get update
 apt-get install -y --no-install-recommends software-properties-common apt-transport-https
 
-apt-key adv --batch --yes --keyserver keyserver.ubuntu.com --recv-keys AA12E97F0881517F
+apt-key adv --batch --yes --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys AA12E97F0881517F
 add-apt-repository -y 'deb https://static.redox-os.org/toolchain/apt /'
 
 apt-get update
diff --git a/src/ci/docker/dist-various-2/Dockerfile b/src/ci/docker/dist-various-2/Dockerfile
index 906255533ad29..e2710a18bdae3 100644
--- a/src/ci/docker/dist-various-2/Dockerfile
+++ b/src/ci/docker/dist-various-2/Dockerfile
@@ -32,7 +32,7 @@ RUN /tmp/build-solaris-toolchain.sh sparcv9 sparcv9 solaris-sparc
 COPY dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh /tmp/
 # We pass the commit id of the port of LLVM's libunwind to the build script.
 # Any update to the commit id here, should cause the container image to be re-built from this point on.
-RUN /tmp/build-x86_64-fortanix-unknown-sgx-toolchain.sh "bbe23902411be88d7388f381becefadd6e3ef819"
+RUN /tmp/build-x86_64-fortanix-unknown-sgx-toolchain.sh "53b586346f2c7870e20b170decdc30729d97c42b"
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
@@ -70,6 +70,7 @@ ENV TARGETS=$TARGETS,x86_64-sun-solaris
 ENV TARGETS=$TARGETS,x86_64-unknown-linux-gnux32
 ENV TARGETS=$TARGETS,x86_64-unknown-cloudabi
 ENV TARGETS=$TARGETS,x86_64-fortanix-unknown-sgx
+ENV TARGETS=$TARGETS,nvptx64-nvidia-cuda
 
 ENV X86_FORTANIX_SGX_LIBS="/x86_64-fortanix-unknown-sgx/lib/"
 
diff --git a/src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh b/src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh
index 391f9b2fff889..3354a796c357e 100755
--- a/src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh
+++ b/src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh
@@ -32,9 +32,8 @@ ln -s ../lib/llvm-5.0/bin/lld /usr/bin/${target}-ld
 ln -s ../../${target} /usr/lib/llvm-5.0/${target}
 
 # Install the C++ runtime libraries from CloudABI Ports.
-echo deb https://nuxi.nl/distfiles/cloudabi-ports/debian/ cloudabi cloudabi > \
-    /etc/apt/sources.list.d/cloudabi.list
-curl 'https://pgp.mit.edu/pks/lookup?op=get&search=0x0DA51B8531344B15' | \
-    apt-key add -
+apt-key adv --batch --yes --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0DA51B8531344B15
+add-apt-repository -y 'deb https://nuxi.nl/distfiles/cloudabi-ports/debian/ cloudabi cloudabi'
+
 apt-get update
-apt-get install -y $(echo ${target} | sed -e s/_/-/g)-cxx-runtime
+apt-get install -y "${target//_/-}-cxx-runtime"
diff --git a/src/ci/docker/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh b/src/ci/docker/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh
index 76921316df2cc..725ec341b9497 100755
--- a/src/ci/docker/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh
+++ b/src/ci/docker/dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh
@@ -12,8 +12,7 @@ target="x86_64-fortanix-unknown-sgx"
 url="https://github.com/fortanix/llvm-project/archive/${1}.tar.gz"
 repo_name="llvm-project"
 
-install_prereq()
-{
+install_prereq() {
     apt-get update
     apt-get install -y --no-install-recommends \
             build-essential \
@@ -22,36 +21,32 @@ install_prereq()
             git
 }
 
-# Clone Fortanix's port of llvm-project to build libunwind that would link with this target.
-# The below method to download a single commit from llvm-project is based on fetch_submodule
-# from init_repo.sh
-fetch_llvm_commit()
-{
-    cached="download-${repo_name}.tar.gz"
-    curl -f -sSL -o ${cached} ${url}
-    tar -xvzf ${cached}
-    mkdir "./${repo_name}" && tar -xf ${cached} -C ${repo_name} --strip-components 1
-}
-
-build_unwind()
-{
+build_unwind() {
+    set -x
     dir_name="${target}_temp"
-    rm -rf "./${dir_name}"
+    rm -rf ${dir_name}
     mkdir -p ${dir_name}
-    cd ${dir_name}
+    pushd ${dir_name}
 
-    retry fetch_llvm_commit
+    # Clone Fortanix's fork of llvm-project which has a port of libunwind
+    fetch_github_commit_archive "$repo_name" "$url"
     cd "${repo_name}/libunwind"
 
     # Build libunwind
     mkdir -p build
     cd build
-    cmake -DCMAKE_BUILD_TYPE="RELEASE" -DRUST_SGX=1 -G "Unix Makefiles" -DLLVM_PATH=../../llvm/ ../
+    cmake -DCMAKE_BUILD_TYPE="RELEASE" -DRUST_SGX=1 -G "Unix Makefiles" \
+        -DLLVM_ENABLE_WARNINGS=1 -DLIBUNWIND_ENABLE_WERROR=1 -DLIBUNWIND_ENABLE_PEDANTIC=0 \
+        -DLLVM_PATH=../../llvm/ ../
     make unwind_static
     install -D "lib/libunwind.a" "/${target}/lib/libunwind.a"
+
+    popd
     rm -rf ${dir_name}
+
+    { set +x; } 2>/dev/null
 }
 
 set -x
 hide_output install_prereq
-hide_output build_unwind
+build_unwind
diff --git a/src/ci/docker/dist-various-2/shared.sh b/src/ci/docker/dist-various-2/shared.sh
index fb917b0510e40..7abace65b9c03 100644
--- a/src/ci/docker/dist-various-2/shared.sh
+++ b/src/ci/docker/dist-various-2/shared.sh
@@ -1,5 +1,5 @@
 hide_output() {
-  set +x
+  { set +x; } 2>/dev/null
   on_err="
 echo ERROR: An error was encountered with the build.
 cat /tmp/build.log
@@ -14,6 +14,7 @@ exit 1
   set -x
 }
 
+# Copied from ../../shared.sh
 function retry {
   echo "Attempting with retry:" "$@"
   local n=1
@@ -31,3 +32,15 @@ function retry {
     }
   done
 }
+
+# Copied from ../../init_repo.sh
+function fetch_github_commit_archive {
+    local module=$1
+    local cached="download-${module//\//-}.tar.gz"
+    retry sh -c "rm -f $cached && \
+        curl -f -sSL -o $cached $2"
+    mkdir $module
+    touch "$module/.git"
+    tar -C $module --strip-components=1 -xf $cached
+    rm $cached
+}
diff --git a/src/ci/docker/dist-x86_64-linux/build-clang.sh b/src/ci/docker/dist-x86_64-linux/build-clang.sh
index ff5b50123fd37..ac681b7168622 100755
--- a/src/ci/docker/dist-x86_64-linux/build-clang.sh
+++ b/src/ci/docker/dist-x86_64-linux/build-clang.sh
@@ -4,26 +4,14 @@ set -ex
 
 source shared.sh
 
-# Currently these commits are all tip-of-tree as of 2018-12-16, used to pick up
-# a fix for rust-lang/rust#56849
-LLVM=032b00a5404865765cda7db3039f39d54964d8b0
-LLD=3e4aa4e8671523321af51449e0569f455ef3ad43
-CLANG=a6b9739069763243020f4ea6fe586bc135fde1f9
+LLVM=llvmorg-8.0.0-rc2
 
-mkdir clang
-cd clang
+mkdir llvm-project
+cd llvm-project
 
-curl -L https://github.com/llvm-mirror/llvm/archive/$LLVM.tar.gz | \
+curl -L https://github.com/llvm/llvm-project/archive/$LLVM.tar.gz | \
   tar xzf - --strip-components=1
 
-mkdir -p tools/clang
-curl -L https://github.com/llvm-mirror/clang/archive/$CLANG.tar.gz | \
-  tar xzf - --strip-components=1 -C tools/clang
-
-mkdir -p tools/lld
-curl -L https://github.com/llvm-mirror/lld/archive/$LLD.tar.gz | \
-  tar zxf - --strip-components=1 -C tools/lld
-
 mkdir clang-build
 cd clang-build
 
@@ -39,20 +27,21 @@ cd clang-build
 #
 # [1]: https://sourceware.org/ml/crossgcc/2008-11/msg00028.html
 INC="/rustroot/include"
-INC="$INC:/rustroot/lib/gcc/x86_64-unknown-linux-gnu/4.8.5/include-fixed"
+INC="$INC:/rustroot/lib/gcc/x86_64-unknown-linux-gnu/5.5.0/include-fixed"
 INC="$INC:/usr/include"
 
 hide_output \
-    cmake .. \
+    cmake ../llvm \
       -DCMAKE_C_COMPILER=/rustroot/bin/gcc \
       -DCMAKE_CXX_COMPILER=/rustroot/bin/g++ \
       -DCMAKE_BUILD_TYPE=Release \
       -DCMAKE_INSTALL_PREFIX=/rustroot \
       -DLLVM_TARGETS_TO_BUILD=X86 \
+      -DLLVM_ENABLE_PROJECTS="clang;lld" \
       -DC_INCLUDE_DIRS="$INC"
 
 hide_output make -j10
 hide_output make install
 
 cd ../..
-rm -rf clang
+rm -rf llvm-project
diff --git a/src/ci/docker/dist-x86_64-linux/build-gcc.sh b/src/ci/docker/dist-x86_64-linux/build-gcc.sh
index 9f3ae55cb3fe6..7f6e94d326ddf 100755
--- a/src/ci/docker/dist-x86_64-linux/build-gcc.sh
+++ b/src/ci/docker/dist-x86_64-linux/build-gcc.sh
@@ -3,9 +3,9 @@ set -ex
 
 source shared.sh
 
-GCC=4.8.5
+GCC=5.5.0
 
-curl https://ftp.gnu.org/gnu/gcc/gcc-$GCC/gcc-$GCC.tar.bz2 | tar xjf -
+curl https://ftp.gnu.org/gnu/gcc/gcc-$GCC/gcc-$GCC.tar.xz | xzcat | tar xf -
 cd gcc-$GCC
 
 # FIXME(#49246): Remove the `sed` below.
diff --git a/src/ci/docker/dist-x86_64-linux/build-perl.sh b/src/ci/docker/dist-x86_64-linux/build-perl.sh
index a6c3d5cb683a8..a678d353d52f5 100755
--- a/src/ci/docker/dist-x86_64-linux/build-perl.sh
+++ b/src/ci/docker/dist-x86_64-linux/build-perl.sh
@@ -11,7 +11,8 @@ cd perl-5.28.0
 # Gotta do some hackery to tell python about our custom OpenSSL build, but other
 # than that fairly normal.
 CC=gcc \
-CFLAGS='-I /rustroot/include' LDFLAGS='-L /rustroot/lib -L /rustroot/lib64' \
+CFLAGS='-I /rustroot/include -fgnu89-inline' \
+LDFLAGS='-L /rustroot/lib -L /rustroot/lib64' \
     hide_output ./configure.gnu
 hide_output make -j10
 hide_output make install
diff --git a/src/ci/docker/run.sh b/src/ci/docker/run.sh
index ad6188568cff2..b4426bbfb962c 100755
--- a/src/ci/docker/run.sh
+++ b/src/ci/docker/run.sh
@@ -20,9 +20,9 @@ travis_time_start
 if [ -f "$docker_dir/$image/Dockerfile" ]; then
     if [ "$CI" != "" ]; then
       hash_key=/tmp/.docker-hash-key.txt
-      find $docker_dir/$image $docker_dir/scripts -type f | \
-        sort | \
-        xargs cat >> $hash_key
+      rm -f "${hash_key}"
+      echo $image >> $hash_key
+      find $docker_dir -type f | sort | xargs cat >> $hash_key
       docker --version >> $hash_key
       cksum=$(sha512sum $hash_key | \
         awk '{print $1}')
@@ -31,7 +31,7 @@ if [ -f "$docker_dir/$image/Dockerfile" ]; then
       echo "Attempting to download $s3url"
       rm -f /tmp/rustci_docker_cache
       set +e
-      retry curl -f -L -C - -o /tmp/rustci_docker_cache "$url"
+      retry curl -y 30 -Y 10 --connect-timeout 30 -f -L -C - -o /tmp/rustci_docker_cache "$url"
       loaded_images=$(docker load -i /tmp/rustci_docker_cache | sed 's/.* sha/sha/')
       set -e
       echo "Downloaded containers:\n$loaded_images"
diff --git a/src/ci/docker/scripts/android-sdk.sh b/src/ci/docker/scripts/android-sdk.sh
index e06c57fbab90c..179f63fc830a6 100644
--- a/src/ci/docker/scripts/android-sdk.sh
+++ b/src/ci/docker/scripts/android-sdk.sh
@@ -20,7 +20,7 @@ download_sysimage() {
     # The output from sdkmanager is so noisy that it will occupy all of the 4 MB
     # log extremely quickly. Thus we must silence all output.
     yes | sdkmanager --licenses > /dev/null
-    sdkmanager platform-tools emulator \
+    yes | sdkmanager platform-tools emulator \
         "platforms;android-$api" \
         "system-images;android-$api;default;$abi" > /dev/null
 }
diff --git a/src/ci/docker/wasm32-unknown/Dockerfile b/src/ci/docker/test-various/Dockerfile
similarity index 63%
rename from src/ci/docker/wasm32-unknown/Dockerfile
rename to src/ci/docker/test-various/Dockerfile
index 161f0c0062fa0..6c419e13c9f05 100644
--- a/src/ci/docker/wasm32-unknown/Dockerfile
+++ b/src/ci/docker/test-various/Dockerfile
@@ -13,14 +13,16 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   gdb \
   xz-utils
 
+# FIXME: build the `ptx-linker` instead.
+RUN curl -sL https://github.com/denzp/rust-ptx-linker/releases/download/v0.9.0-alpha.2/rust-ptx-linker.linux64.tar.gz | \
+  tar -xzvC /usr/bin
+
 RUN curl -sL https://nodejs.org/dist/v9.2.0/node-v9.2.0-linux-x64.tar.xz | \
-    tar -xJ
+  tar -xJ
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
-ENV TARGETS=wasm32-unknown-unknown
-
 ENV RUST_CONFIGURE_ARGS \
   --set build.nodejs=/node-v9.2.0-linux-x64/bin/node \
   --set rust.lld
@@ -31,11 +33,18 @@ ENV RUST_CONFIGURE_ARGS \
 # other contexts as well
 ENV NO_DEBUG_ASSERTIONS=1
 
-ENV SCRIPT python2.7 /checkout/x.py test --target $TARGETS \
+ENV WASM_TARGETS=wasm32-unknown-unknown
+ENV WASM_SCRIPT python2.7 /checkout/x.py test --target $WASM_TARGETS \
   src/test/run-make \
   src/test/ui \
   src/test/run-pass \
   src/test/compile-fail \
   src/test/mir-opt \
   src/test/codegen-units \
-  src/libcore \
+  src/libcore
+
+ENV NVPTX_TARGETS=nvptx64-nvidia-cuda
+ENV NVPTX_SCRIPT python2.7 /checkout/x.py test --target $NVPTX_TARGETS \
+  src/test/run-make
+
+ENV SCRIPT $WASM_SCRIPT && $NVPTX_SCRIPT
diff --git a/src/ci/docker/x86_64-gnu-debug/Dockerfile b/src/ci/docker/x86_64-gnu-debug/Dockerfile
index bdde7ad7fe854..1c7eff68adc15 100644
--- a/src/ci/docker/x86_64-gnu-debug/Dockerfile
+++ b/src/ci/docker/x86_64-gnu-debug/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:16.04
+FROM ubuntu:18.10
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
@@ -7,18 +7,37 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   curl \
   ca-certificates \
   python2.7 \
+  python2.7-dev \
+  libxml2-dev \
+  libncurses-dev \
+  libedit-dev \
+  swig \
+  doxygen \
   git \
   cmake \
   sudo \
   gdb \
-  xz-utils
+  xz-utils \
+  lld \
+  clang
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
+ENV RUSTBUILD_FORCE_CLANG_BASED_TESTS 1
 ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
+
 ENV RUST_CONFIGURE_ARGS \
       --build=x86_64-unknown-linux-gnu \
       --enable-debug \
-      --enable-optimize
-ENV SCRIPT python2.7 ../x.py build
+      --enable-lld \
+      --enable-lldb \
+      --enable-optimize \
+      --set llvm.use-linker=lld \
+      --set target.x86_64-unknown-linux-gnu.linker=clang \
+      --set target.x86_64-unknown-linux-gnu.cc=clang \
+      --set target.x86_64-unknown-linux-gnu.cxx=clang++
+
+ENV SCRIPT \
+  python2.7 ../x.py build && \
+  python2.7 ../x.py test src/test/run-make-fulldeps --test-args clang
diff --git a/src/ci/docker/x86_64-gnu-tools/checktools.sh b/src/ci/docker/x86_64-gnu-tools/checktools.sh
index 2e5b335950166..3343716419ff4 100755
--- a/src/ci/docker/x86_64-gnu-tools/checktools.sh
+++ b/src/ci/docker/x86_64-gnu-tools/checktools.sh
@@ -23,6 +23,7 @@ python2.7 "$X_PY" test --no-fail-fast \
     src/doc/nomicon \
     src/doc/reference \
     src/doc/rust-by-example \
+    src/doc/embedded-book \
     src/tools/clippy \
     src/tools/rls \
     src/tools/rustfmt \
diff --git a/src/ci/init_repo.sh b/src/ci/init_repo.sh
index be2cadbbe6cf2..3dfd338157617 100755
--- a/src/ci/init_repo.sh
+++ b/src/ci/init_repo.sh
@@ -34,19 +34,19 @@ if grep -q RUST_RELEASE_CHANNEL=beta src/ci/run.sh; then
   git fetch origin --unshallow beta master
 fi
 
-function fetch_submodule {
+# Duplicated in docker/dist-various-2/shared.sh
+function fetch_github_commit_archive {
     local module=$1
     local cached="download-${module//\//-}.tar.gz"
     retry sh -c "rm -f $cached && \
-        curl -sSL -o $cached $2"
+        curl -f -sSL -o $cached $2"
     mkdir $module
     touch "$module/.git"
     tar -C $module --strip-components=1 -xf $cached
     rm $cached
 }
 
-included="src/llvm src/llvm-emscripten src/doc/book src/doc/rust-by-example"
-included="$included src/tools/lld src/tools/clang src/tools/lldb"
+included="src/llvm-project src/llvm-emscripten src/doc/book src/doc/rust-by-example"
 modules="$(git config --file .gitmodules --get-regexp '\.path$' | cut -d' ' -f2)"
 modules=($modules)
 use_git=""
@@ -59,7 +59,7 @@ for i in ${!modules[@]}; do
         git rm $module
         url=${urls[$i]}
         url=${url/\.git/}
-        fetch_submodule $module "$url/archive/$commit.tar.gz" &
+        fetch_github_commit_archive $module "$url/archive/$commit.tar.gz" &
         continue
     else
         use_git="$use_git $module"
diff --git a/src/ci/run.sh b/src/ci/run.sh
index b0e1b1651055f..42d0d7db5964c 100755
--- a/src/ci/run.sh
+++ b/src/ci/run.sh
@@ -82,7 +82,7 @@ fi
 SCCACHE_IDLE_TIMEOUT=10800 sccache --start-server || true
 
 if [ "$RUN_CHECK_WITH_PARALLEL_QUERIES" != "" ]; then
-  $SRC/configure --enable-experimental-parallel-queries
+  $SRC/configure --enable-parallel-compiler
   CARGO_INCREMENTAL=0 python2.7 ../x.py check
   rm -f config.toml
   rm -rf build
diff --git a/src/ci/shared.sh b/src/ci/shared.sh
index 4a49f3441a41d..3ba64ad412064 100644
--- a/src/ci/shared.sh
+++ b/src/ci/shared.sh
@@ -5,6 +5,7 @@
 # marked as an executable file in git.
 
 # See http://unix.stackexchange.com/questions/82598
+# Duplicated in docker/dist-various-2/shared.sh
 function retry {
   echo "Attempting with retry:" "$@"
   local n=1
diff --git a/src/doc/embedded-book b/src/doc/embedded-book
new file mode 160000
index 0000000000000..bd2778f304989
--- /dev/null
+++ b/src/doc/embedded-book
@@ -0,0 +1 @@
+Subproject commit bd2778f304989ee52be8201504d6ec621dd60ca9
diff --git a/src/doc/guide-error-handling.md b/src/doc/guide-error-handling.md
index 54fa529f3aa8e..fd71d3e3c8e79 100644
--- a/src/doc/guide-error-handling.md
+++ b/src/doc/guide-error-handling.md
@@ -1,4 +1,4 @@
 % Error Handling in Rust
 
 This content has moved into
-[the Rust Programming Language book](book/error-handling.html).
+[the Rust Programming Language book](book/ch09-00-error-handling.html).
diff --git a/src/doc/guide-ownership.md b/src/doc/guide-ownership.md
index 884f14726ca87..767dafc5baf92 100644
--- a/src/doc/guide-ownership.md
+++ b/src/doc/guide-ownership.md
@@ -1,4 +1,4 @@
 % The (old) Rust Ownership Guide
 
 This content has moved into
-[the Rust Programming Language book](book/ownership.html).
+[the Rust Programming Language book](book/ch04-00-understanding-ownership.html).
diff --git a/src/doc/guide-pointers.md b/src/doc/guide-pointers.md
index dc80ec4399131..bafdb2fe0bbc3 100644
--- a/src/doc/guide-pointers.md
+++ b/src/doc/guide-pointers.md
@@ -2,6 +2,6 @@
 
 This content has been removed, with no direct replacement. Rust only
 has two built-in pointer types now,
-[references](book/references-and-borrowing.html) and [raw
+[references](book/ch04-02-references-and-borrowing.html) and [raw
 pointers](book/raw-pointers.html). Older Rusts had many more pointer
 types, they’re gone now.
diff --git a/src/doc/guide-testing.md b/src/doc/guide-testing.md
index 67bcb0a5e546a..28d9fb48b73e7 100644
--- a/src/doc/guide-testing.md
+++ b/src/doc/guide-testing.md
@@ -1,4 +1,4 @@
 % The (old) Rust Testing Guide
 
 This content has moved into
-[the Rust Programming Language book](book/testing.html).
+[the Rust Programming Language book](book/ch11-00-testing.html).
diff --git a/src/doc/index.md b/src/doc/index.md
index 55897e5a3e906..0a2a80e8fd6e2 100644
--- a/src/doc/index.md
+++ b/src/doc/index.md
@@ -52,6 +52,12 @@ If reading multiple hundreds of pages about a language isn't your style, then
 a lot of words, RBE shows off a bunch of code, and keeps the talking to a
 minimum. It also includes exercises!
 
+## Rustlings
+
+[Rustlings](https://github.com/rust-lang/rustlings) guides you through downloading and setting up the Rust toolchain,
+and teaches you the basics of reading and writing Rust syntax. It's an
+alternative to Rust by Example that works with your own environment.
+
 # Use Rust
 
 Once you've gotten familiar with the language, these resources can help you
@@ -71,6 +77,10 @@ accomplishing various tasks.
   </form>
 </div>
 
+## The Edition Guide
+
+[The Edition Guide](edition-guide/index.html) describes the Rust editions.
+
 ## The Rustc Book
 
 [The Rustc Book](rustc/index.html) describes the Rust compiler, `rustc`.
@@ -113,3 +123,19 @@ Rust. It's also sometimes called "the 'nomicon."
 [The `rustc` Guide](https://rust-lang.github.io/rustc-guide/) documents how
 the compiler works and how to contribute to it. This is useful if you want to build
 or modify the Rust compiler from source (e.g. to target something non-standard).
+
+# Specialize Rust
+
+When using Rust in specific domain areas, consider using the following resources tailored to each domain.
+
+## Embedded Systems
+
+When developing for Bare Metal or Embedded Linux systems, you may find these resources maintained by the [Embedded Working Group] useful.
+
+[Embedded Working Group]: https://github.com/rust-embedded
+
+### The Embedded Rust Book
+
+[The Embedded Rust Book] is targeted at developers familiar with embedded development and familiar with Rust, but have not used Rust for embedded development.
+
+[The Embedded Rust Book]: embedded-book/index.html
diff --git a/src/doc/rustc/src/SUMMARY.md b/src/doc/rustc/src/SUMMARY.md
index e4c0939fd4636..34708d1847f6b 100644
--- a/src/doc/rustc/src/SUMMARY.md
+++ b/src/doc/rustc/src/SUMMARY.md
@@ -13,4 +13,5 @@
 - [Targets](targets/index.md)
     - [Built-in Targets](targets/built-in.md)
     - [Custom Targets](targets/custom.md)
-- [Contributing to `rustc`](contributing.md)
\ No newline at end of file
+- [Linker-plugin based LTO](linker-plugin-lto.md)
+- [Contributing to `rustc`](contributing.md)
diff --git a/src/doc/rustc/src/codegen-options/index.md b/src/doc/rustc/src/codegen-options/index.md
index 94f21042c8fdd..a616409d9a400 100644
--- a/src/doc/rustc/src/codegen-options/index.md
+++ b/src/doc/rustc/src/codegen-options/index.md
@@ -187,7 +187,7 @@ This flag lets you control debug information:
 
 This flag lets you control the optimization level.
 
-* `0`: no optimizations
+* `0`: no optimizations, also turn on `cfg(debug_assertions)`.
 * `1`: basic optimizations
 * `2`: some optimizations
 * `3`: all optimizations
diff --git a/src/doc/rustc/src/command-line-arguments.md b/src/doc/rustc/src/command-line-arguments.md
index b60c55240140e..d7e789b5a11f7 100644
--- a/src/doc/rustc/src/command-line-arguments.md
+++ b/src/doc/rustc/src/command-line-arguments.md
@@ -42,11 +42,11 @@ This flag prints out various information about the compiler.
 
 ## `-g`: include debug information
 
-A synonym for `-C debug-level=2`.
+A synonym for `-C debuginfo=2`, for more see [here](codegen-options/index.html#debuginfo).
 
 ## `-O`: optimize your code
 
-A synonym for `-C opt-level=2`.
+A synonym for `-C opt-level=2`, for more see [here](codegen-options/index.html#opt-level).
 
 ## `-o`: filename of the output
 
diff --git a/src/doc/rustc/src/contributing.md b/src/doc/rustc/src/contributing.md
index 3a1cafe8a6153..25a5c97b0a120 100644
--- a/src/doc/rustc/src/contributing.md
+++ b/src/doc/rustc/src/contributing.md
@@ -1,6 +1,12 @@
 # Contributing to rustc
 
 We'd love to have your help improving `rustc`! To that end, we've written [a
-whole book](https://rust-lang.github.io/rustc-guide/) on its
+whole book][rustc_guide] on its
 internals, how it works, and how to get started working on it. To learn
 more, you'll want to check that out.
+
+If you would like to contribute to _this_ book, you can find its source in the
+rustc source at [src/doc/rustc][rustc_book].
+
+[rustc_guide]: https://rust-lang.github.io/rustc-guide/
+[rustc_book]: https://github.com/rust-lang/rust/tree/master/src/doc/rustc
diff --git a/src/doc/rustc/src/linker-plugin-lto.md b/src/doc/rustc/src/linker-plugin-lto.md
new file mode 100644
index 0000000000000..73a2efcb33a75
--- /dev/null
+++ b/src/doc/rustc/src/linker-plugin-lto.md
@@ -0,0 +1,108 @@
+# Linker-plugin-LTO
+
+The `-C linker-plugin-lto` flag allows for deferring the LTO optimization
+to the actual linking step, which in turn allows for performing
+interprocedural optimizations across programming language boundaries if
+all the object files being linked were created by LLVM based toolchains.
+The prime example here would be linking Rust code together with
+Clang-compiled C/C++ code.
+
+## Usage
+
+There are two main cases how linker plugin based LTO can be used:
+
+ - compiling a Rust `staticlib` that is used as a C ABI dependency
+ - compiling a Rust binary where `rustc` invokes the linker
+
+In both cases the Rust code has to be compiled with `-C linker-plugin-lto` and
+the C/C++ code with `-flto` or `-flto=thin` so that object files are emitted
+as LLVM bitcode.
+
+### Rust `staticlib` as dependency in C/C++ program
+
+In this case the Rust compiler just has to make sure that the object files in
+the `staticlib` are in the right format. For linking, a linker with the
+LLVM plugin must be used (e.g. LLD).
+
+Using `rustc` directly:
+
+```bash
+# Compile the Rust staticlib
+rustc --crate-type=staticlib -Clinker-plugin-lto -Copt-level=2 ./lib.rs
+# Compile the C code with `-flto=thin`
+clang -c -O2 -flto=thin -o main.o ./main.c
+# Link everything, making sure that we use an appropriate linker
+clang -flto=thin -fuse-ld=lld -L . -l"name-of-your-rust-lib" -o main -O2 ./cmain.o
+```
+
+Using `cargo`:
+
+```bash
+# Compile the Rust staticlib
+RUSTFLAGS="-Clinker-plugin-lto" cargo build --release
+# Compile the C code with `-flto=thin`
+clang -c -O2 -flto=thin -o main.o ./main.c
+# Link everything, making sure that we use an appropriate linker
+clang -flto=thin -fuse-ld=lld -L . -l"name-of-your-rust-lib" -o main -O2 ./cmain.o
+```
+
+### C/C++ code as a dependency in Rust
+
+In this case the linker will be invoked by `rustc`. We again have to make sure
+that an appropriate linker is used.
+
+Using `rustc` directly:
+
+```bash
+# Compile C code with `-flto`
+clang ./clib.c -flto=thin -c -o ./clib.o -O2
+# Create a static library from the C code
+ar crus ./libxyz.a ./clib.o
+
+# Invoke `rustc` with the additional arguments
+rustc -Clinker-plugin-lto -L. -Copt-level=2 -Clinker=clang -Clink-arg=-fuse-ld=lld ./main.rs
+```
+
+Using `cargo` directly:
+
+```bash
+# Compile C code with `-flto`
+clang ./clib.c -flto=thin -c -o ./clib.o -O2
+# Create a static library from the C code
+ar crus ./libxyz.a ./clib.o
+
+# Set the linking arguments via RUSTFLAGS
+RUSTFLAGS="-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld" cargo build --release
+```
+
+### Explicitly specifying the linker plugin to be used by `rustc`
+
+If one wants to use a linker other than LLD, the LLVM linker plugin has to be
+specified explicitly. Otherwise the linker cannot read the object files. The
+path to the plugin is passed as an argument to the `-Clinker-plugin-lto`
+option:
+
+```bash
+rustc -Clinker-plugin-lto="/path/to/LLVMgold.so" -L. -Copt-level=2 ./main.rs
+```
+
+
+## Toolchain Compatibility
+
+In order for this kind of LTO to work, the LLVM linker plugin must be able to
+handle the LLVM bitcode produced by both `rustc` and `clang`.
+
+Best results are achieved by using a `rustc` and `clang` that are based on the
+exact same version of LLVM. One can use `rustc -vV` in order to view the LLVM
+used by a given `rustc` version. Note that the version number given
+here is only an approximation as Rust sometimes uses unstable revisions of
+LLVM. However, the approximation is usually reliable.
+
+The following table shows known good combinations of toolchain versions.
+
+|           | Clang 7   | Clang 8   |
+|-----------|-----------|-----------|
+| Rust 1.34 |     ✗     |     ✓     |
+| Rust 1.35 |     ✗     |    ✓(?)   |
+
+Note that the compatibility policy for this feature might change in the future.
diff --git a/src/doc/rustc/src/lints/levels.md b/src/doc/rustc/src/lints/levels.md
index 072c7585934e8..d315e0f8ca9e5 100644
--- a/src/doc/rustc/src/lints/levels.md
+++ b/src/doc/rustc/src/lints/levels.md
@@ -90,7 +90,9 @@ This lint level gives you that.
 'forbid' is a special lint level that's stronger than 'deny'. It's the same
 as 'deny' in that a lint at this level will produce an error, but unlike the
 'deny' level, the 'forbid' level can not be overridden to be anything lower
-than an error.
+than an error.  However, lint levels may still be capped with `--cap-lints`
+(see below) so `rustc --cap-lints warn` will make lints set to 'forbid' just
+warn.
 
 ## Configuring warning levels
 
diff --git a/src/doc/rustdoc/src/documentation-tests.md b/src/doc/rustdoc/src/documentation-tests.md
index dcc13f53493f4..c9acd3c307b54 100644
--- a/src/doc/rustdoc/src/documentation-tests.md
+++ b/src/doc/rustdoc/src/documentation-tests.md
@@ -236,6 +236,23 @@ appears to the reader as the initial idea but works with doc tests:
 /// ```
 ```
 
+As of version 1.34.0, one can also omit the `fn main()`, but you will have to
+disambiguate the error type:
+
+```ignore
+/// ```
+/// use std::io;
+/// let mut input = String::new();
+/// io::stdin().read_line(&mut input)?;
+/// # Ok::<(), io::Error>(())
+/// ```
+```
+
+This is an unfortunate consequence of the `?` operator adding an implicit
+conversion, so type inference fails because the type is not unique. Please note
+that you must write the `(())` in one sequence without intermediate whitespace
+so that rustdoc understands you want an implicit `Result`-returning function.
+
 ## Documenting macros
 
 Here’s an example of documenting a macro:
diff --git a/src/doc/rustdoc/src/unstable-features.md b/src/doc/rustdoc/src/unstable-features.md
index 905b06465340a..3463cdb126cc6 100644
--- a/src/doc/rustdoc/src/unstable-features.md
+++ b/src/doc/rustdoc/src/unstable-features.md
@@ -1,9 +1,8 @@
 # Unstable features
 
 Rustdoc is under active development, and like the Rust compiler, some features are only available
-on the nightly releases. Some of these are new and need some more testing before they're able to get
-released to the world at large, and some of them are tied to features in the Rust compiler that are
-themselves unstable. Several features here require a matching `#![feature(...)]` attribute to
+on nightly releases. Some of these features are new and need some more testing before they're able to be
+released to the world at large, and some of them are tied to features in the Rust compiler that are unstable. Several features here require a matching `#![feature(...)]` attribute to
 enable, and thus are more fully documented in the [Unstable Book]. Those sections will link over
 there as necessary.
 
@@ -417,3 +416,15 @@ JavaScript, and font files in a single location, rather than duplicating it once
 (grouping of crate docs generated into the same output directory, like with `cargo doc`). Per-crate
 files like the search index will still load from the documentation root, but anything that gets
 renamed with `--resource-suffix` will load from the given path.
+
+### `--persist-doctests`: persist doctest executables after running
+
+Using this flag looks like this:
+
+```bash
+$ rustdoc src/lib.rs --test -Z unstable-options --persist-doctests target/rustdoctest
+```
+
+This flag allows you to keep doctest executables around after they're compiled or run.
+Usually, rustdoc will immediately discard a compiled doctest after it's been tested, but
+with this option, you can keep those binaries around for farther testing.
diff --git a/src/doc/unstable-book/src/language-features/crate-visibility-modifier.md b/src/doc/unstable-book/src/language-features/crate-visibility-modifier.md
index 11b3ee8edf0b1..b59859dd348e7 100644
--- a/src/doc/unstable-book/src/language-features/crate-visibility-modifier.md
+++ b/src/doc/unstable-book/src/language-features/crate-visibility-modifier.md
@@ -1,8 +1,8 @@
 # `crate_visibility_modifier`
 
-The tracking issue for this feature is: [#45388]
+The tracking issue for this feature is: [#53120]
 
-[#45388]: https://github.com/rust-lang/rust/issues/45388
+[#53120]: https://github.com/rust-lang/rust/issues/53120
 
 -----
 
diff --git a/src/doc/unstable-book/src/language-features/generators.md b/src/doc/unstable-book/src/language-features/generators.md
index 968534e58bd9e..426fc01a6b051 100644
--- a/src/doc/unstable-book/src/language-features/generators.md
+++ b/src/doc/unstable-book/src/language-features/generators.md
@@ -29,6 +29,7 @@ A syntactical example of a generator is:
 #![feature(generators, generator_trait)]
 
 use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
 
 fn main() {
     let mut generator = || {
@@ -36,11 +37,11 @@ fn main() {
         return "foo"
     };
 
-    match unsafe { generator.resume() } {
+    match Pin::new(&mut generator).resume() {
         GeneratorState::Yielded(1) => {}
         _ => panic!("unexpected value from resume"),
     }
-    match unsafe { generator.resume() } {
+    match Pin::new(&mut generator).resume() {
         GeneratorState::Complete("foo") => {}
         _ => panic!("unexpected value from resume"),
     }
@@ -60,6 +61,7 @@ prints all numbers in order:
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
     let mut generator = || {
@@ -69,9 +71,9 @@ fn main() {
     };
 
     println!("1");
-    unsafe { generator.resume() };
+    Pin::new(&mut generator).resume();
     println!("3");
-    unsafe { generator.resume() };
+    Pin::new(&mut generator).resume();
     println!("5");
 }
 ```
@@ -86,13 +88,14 @@ Feedback on the design and usage is always appreciated!
 The `Generator` trait in `std::ops` currently looks like:
 
 ```
-# #![feature(generator_trait)]
+# #![feature(arbitrary_self_types, generator_trait)]
 # use std::ops::GeneratorState;
+# use std::pin::Pin;
 
 pub trait Generator {
     type Yield;
     type Return;
-    unsafe fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return>;
+    fn resume(self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return>;
 }
 ```
 
@@ -167,6 +170,7 @@ Let's take a look at an example to see what's going on here:
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
     let ret = "foo";
@@ -175,17 +179,18 @@ fn main() {
         return ret
     };
 
-    unsafe { generator.resume() };
-    unsafe { generator.resume() };
+    Pin::new(&mut generator).resume();
+    Pin::new(&mut generator).resume();
 }
 ```
 
 This generator literal will compile down to something similar to:
 
 ```rust
-#![feature(generators, generator_trait)]
+#![feature(arbitrary_self_types, generators, generator_trait)]
 
 use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
 
 fn main() {
     let ret = "foo";
@@ -200,9 +205,9 @@ fn main() {
             type Yield = i32;
             type Return = &'static str;
 
-            unsafe fn resume(&mut self) -> GeneratorState<i32, &'static str> {
+            fn resume(mut self: Pin<&mut Self>) -> GeneratorState<i32, &'static str> {
                 use std::mem;
-                match mem::replace(self, __Generator::Done) {
+                match mem::replace(&mut *self, __Generator::Done) {
                     __Generator::Start(s) => {
                         *self = __Generator::Yield1(s);
                         GeneratorState::Yielded(1)
@@ -223,8 +228,8 @@ fn main() {
         __Generator::Start(ret)
     };
 
-    unsafe { generator.resume() };
-    unsafe { generator.resume() };
+    Pin::new(&mut generator).resume();
+    Pin::new(&mut generator).resume();
 }
 ```
 
diff --git a/src/doc/unstable-book/src/language-features/plugin.md b/src/doc/unstable-book/src/language-features/plugin.md
index 03ea392c86307..cab350381d2bd 100644
--- a/src/doc/unstable-book/src/language-features/plugin.md
+++ b/src/doc/unstable-book/src/language-features/plugin.md
@@ -52,6 +52,7 @@ that implements Roman numeral integer literals.
 #![feature(plugin_registrar, rustc_private)]
 
 extern crate syntax;
+extern crate syntax_pos;
 extern crate rustc;
 extern crate rustc_plugin;
 
@@ -59,7 +60,7 @@ use syntax::parse::token;
 use syntax::tokenstream::TokenTree;
 use syntax::ext::base::{ExtCtxt, MacResult, DummyResult, MacEager};
 use syntax::ext::build::AstBuilder;  // A trait for expr_usize.
-use syntax::ext::quote::rt::Span;
+use syntax_pos::Span;
 use rustc_plugin::Registry;
 
 fn expand_rn(cx: &mut ExtCtxt, sp: Span, args: &[TokenTree])
diff --git a/src/doc/unstable-book/src/language-features/repr-align-enum.md b/src/doc/unstable-book/src/language-features/repr-align-enum.md
new file mode 100644
index 0000000000000..415c6ebe8b4bc
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/repr-align-enum.md
@@ -0,0 +1,42 @@
+# `repr_align_enum`
+
+The tracking issue for this feature is: [#57996]
+
+[#57996]: https://github.com/rust-lang/rust/issues/57996
+
+------------------------
+
+The `repr_align_enum` feature allows using the `#[repr(align(x))]` attribute
+on enums, similarly to structs.
+
+# Examples
+
+```rust
+#![feature(repr_align_enum)]
+
+#[repr(align(8))]
+enum Aligned {
+    Foo,
+    Bar { value: u32 },
+}
+
+fn main() {
+    assert_eq!(std::mem::align_of::<Aligned>(), 8);
+}
+```
+
+This is equivalent to using an aligned wrapper struct everywhere:
+
+```rust
+#[repr(align(8))]
+struct Aligned(Unaligned);
+
+enum Unaligned {
+    Foo,
+    Bar { value: u32 },
+}
+
+fn main() {
+    assert_eq!(std::mem::align_of::<Aligned>(), 8);
+}
+```
diff --git a/src/doc/unstable-book/src/library-features/is-sorted.md b/src/doc/unstable-book/src/library-features/is-sorted.md
new file mode 100644
index 0000000000000..e3b7dc3b28eb2
--- /dev/null
+++ b/src/doc/unstable-book/src/library-features/is-sorted.md
@@ -0,0 +1,11 @@
+# `is_sorted`
+
+The tracking issue for this feature is: [#53485]
+
+[#53485]: https://github.com/rust-lang/rust/issues/53485
+
+------------------------
+
+Add the methods `is_sorted`, `is_sorted_by` and `is_sorted_by_key` to `[T]`;
+add the methods `is_sorted`, `is_sorted_by` and `is_sorted_by_key` to
+`Iterator`.
diff --git a/src/etc/gdb_rust_pretty_printing.py b/src/etc/gdb_rust_pretty_printing.py
index 08ae289d60374..a6b09722e1c94 100755
--- a/src/etc/gdb_rust_pretty_printing.py
+++ b/src/etc/gdb_rust_pretty_printing.py
@@ -16,7 +16,7 @@
 # This fix went in 8.1, so check for that.
 # See https://github.com/rust-lang/rust/issues/56730
 gdb_81 = False
-_match = re.match('([0-9]+)\\.([0-9]+)', gdb.VERSION)
+_match = re.search('([0-9]+)\\.([0-9]+)', gdb.VERSION)
 if _match:
     if int(_match.group(1)) > 8 or (int(_match.group(1)) == 8 and int(_match.group(2)) >= 1):
         gdb_81 = True
@@ -330,19 +330,20 @@ def children_of_node(boxed_node, height, want_values):
         leaf = node_ptr['data']
     else:
         leaf = node_ptr.dereference()
-    keys = leaf['keys']['value']['value']
+    keys = leaf['keys']
     if want_values:
-        values = leaf['vals']['value']['value']
+        values = leaf['vals']
     length = int(leaf['len'])
     for i in xrange(0, length + 1):
         if height > 0:
-            for child in children_of_node(node_ptr['edges'][i], height - 1, want_values):
+            child_ptr = node_ptr['edges'][i]['value']['value']
+            for child in children_of_node(child_ptr, height - 1, want_values):
                 yield child
         if i < length:
             if want_values:
-                yield (keys[i], values[i])
+                yield (keys[i]['value']['value'], values[i]['value']['value'])
             else:
-                yield keys[i]
+                yield keys[i]['value']['value']
 
 class RustStdBTreeSetPrinter(object):
     def __init__(self, val):
diff --git a/src/etc/generate-deriving-span-tests.py b/src/etc/generate-deriving-span-tests.py
index 3d35ae07fbd68..1c525101c76f6 100755
--- a/src/etc/generate-deriving-span-tests.py
+++ b/src/etc/generate-deriving-span-tests.py
@@ -8,14 +8,12 @@
 sample usage: src/etc/generate-deriving-span-tests.py
 """
 
-import os, datetime, stat, re
+import os, stat
 
 TEST_DIR = os.path.abspath(
     os.path.join(os.path.dirname(__file__), '../test/ui/derives/'))
 
-YEAR = datetime.datetime.now().year
-
-TEMPLATE = """
+TEMPLATE = """\
 // This file was auto-generated using 'src/etc/generate-deriving-span-tests.py'
 
 {error_deriving}
@@ -63,19 +61,11 @@ def create_test_case(type, trait, super_traits, error_count):
 
     errors = '\n'.join('//~%s ERROR' % ('^' * n) for n in range(error_count))
     code = string.format(traits = all_traits, errors = errors)
-    return TEMPLATE.format(year = YEAR, error_deriving=error_deriving, code = code)
+    return TEMPLATE.format(error_deriving=error_deriving, code = code)
 
 def write_file(name, string):
     test_file = os.path.join(TEST_DIR, 'derives-span-%s.rs' % name)
 
-    with open(test_file) as f:
-        old_str = f.read()
-        old_str_ignoring_date = re.sub(r'^// Copyright \d+',
-                                        '// Copyright {year}'.format(year = YEAR), old_str)
-        if old_str_ignoring_date == string:
-            # if all we're doing is updating the copyright year, ignore it
-            return 0
-
     # set write permission if file exists, so it can be changed
     if os.path.exists(test_file):
         os.chmod(test_file, stat.S_IWUSR)
@@ -86,8 +76,6 @@ def write_file(name, string):
     # mark file read-only
     os.chmod(test_file, stat.S_IRUSR|stat.S_IRGRP|stat.S_IROTH)
 
-    return 1
-
 
 ENUM = 1
 STRUCT = 2
@@ -110,15 +98,11 @@ def write_file(name, string):
                               ('Hash', [], 1)]:
     traits[trait] = (ALL, supers, errs)
 
-files = 0
-
 for (trait, (types, super_traits, error_count)) in traits.items():
     mk = lambda ty: create_test_case(ty, trait, super_traits, error_count)
     if types & ENUM:
-        files += write_file(trait + '-enum', mk(ENUM_TUPLE))
-        files += write_file(trait + '-enum-struct-variant', mk(ENUM_STRUCT))
+        write_file(trait + '-enum', mk(ENUM_TUPLE))
+        write_file(trait + '-enum-struct-variant', mk(ENUM_STRUCT))
     if types & STRUCT:
-        files += write_file(trait + '-struct', mk(STRUCT_FIELDS))
-        files += write_file(trait + '-tuple-struct', mk(STRUCT_TUPLE))
-
-print('Generated {files} deriving span test{}.'.format('s' if files != 1 else '', files = files))
+        write_file(trait + '-struct', mk(STRUCT_FIELDS))
+        write_file(trait + '-tuple-struct', mk(STRUCT_TUPLE))
diff --git a/src/etc/generate-keyword-tests.py b/src/etc/generate-keyword-tests.py
index 9936ce71b76bc..bc046a8f42d0b 100755
--- a/src/etc/generate-keyword-tests.py
+++ b/src/etc/generate-keyword-tests.py
@@ -15,7 +15,7 @@
 import stat
 
 
-template = """
+template = """\
 // This file was auto-generated using 'src/etc/generate-keyword-tests.py %s'
 
 fn main() {
@@ -35,7 +35,7 @@
         os.chmod(test_file, stat.S_IWUSR)
 
     with open(test_file, 'wt') as f:
-        f.write(template % (datetime.datetime.now().year, kw, kw, kw))
+        f.write(template % (kw, kw, kw))
 
     # mark file read-only
     os.chmod(test_file, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)
diff --git a/src/liballoc/Cargo.toml b/src/liballoc/Cargo.toml
index 861c7cecb8879..f6d6c1de8f511 100644
--- a/src/liballoc/Cargo.toml
+++ b/src/liballoc/Cargo.toml
@@ -4,6 +4,7 @@ name = "alloc"
 version = "0.0.0"
 autotests = false
 autobenches = false
+edition = "2018"
 
 [lib]
 name = "alloc"
diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index 096cb51e0d3ef..ec652df3b37a4 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -227,9 +227,9 @@ pub fn handle_alloc_error(layout: Layout) -> ! {
 #[cfg(test)]
 mod tests {
     extern crate test;
-    use self::test::Bencher;
-    use boxed::Box;
-    use alloc::{Global, Alloc, Layout, handle_alloc_error};
+    use test::Bencher;
+    use crate::boxed::Box;
+    use crate::alloc::{Global, Alloc, Layout, handle_alloc_error};
 
     #[test]
     fn allocate_zeroed() {
diff --git a/src/liballoc/benches/btree/map.rs b/src/liballoc/benches/btree/map.rs
index a6f584534d174..4c17bdc3e9e9d 100644
--- a/src/liballoc/benches/btree/map.rs
+++ b/src/liballoc/benches/btree/map.rs
@@ -1,6 +1,7 @@
 use std::iter::Iterator;
 use std::vec::Vec;
 use std::collections::BTreeMap;
+
 use rand::{Rng, seq::SliceRandom, thread_rng};
 use test::{Bencher, black_box};
 
diff --git a/src/liballoc/benches/btree/mod.rs b/src/liballoc/benches/btree/mod.rs
index 4dc2dfd9153e7..095ca5dd2e21b 100644
--- a/src/liballoc/benches/btree/mod.rs
+++ b/src/liballoc/benches/btree/mod.rs
@@ -1 +1,2 @@
 mod map;
+mod set;
diff --git a/src/liballoc/benches/btree/set.rs b/src/liballoc/benches/btree/set.rs
new file mode 100644
index 0000000000000..08e1db5fbb74d
--- /dev/null
+++ b/src/liballoc/benches/btree/set.rs
@@ -0,0 +1,88 @@
+use std::collections::BTreeSet;
+
+use rand::{thread_rng, Rng};
+use test::{black_box, Bencher};
+
+fn random(n1: u32, n2: u32) -> [BTreeSet<usize>; 2] {
+    let mut rng = thread_rng();
+    let mut set1 = BTreeSet::new();
+    let mut set2 = BTreeSet::new();
+    for _ in 0..n1 {
+        let i = rng.gen::<usize>();
+        set1.insert(i);
+    }
+    for _ in 0..n2 {
+        let i = rng.gen::<usize>();
+        set2.insert(i);
+    }
+    [set1, set2]
+}
+
+fn staggered(n1: u32, n2: u32) -> [BTreeSet<u32>; 2] {
+    let mut even = BTreeSet::new();
+    let mut odd = BTreeSet::new();
+    for i in 0..n1 {
+        even.insert(i * 2);
+    }
+    for i in 0..n2 {
+        odd.insert(i * 2 + 1);
+    }
+    [even, odd]
+}
+
+fn neg_vs_pos(n1: u32, n2: u32) -> [BTreeSet<i32>; 2] {
+    let mut neg = BTreeSet::new();
+    let mut pos = BTreeSet::new();
+    for i in -(n1 as i32)..=-1 {
+        neg.insert(i);
+    }
+    for i in 1..=(n2 as i32) {
+        pos.insert(i);
+    }
+    [neg, pos]
+}
+
+fn pos_vs_neg(n1: u32, n2: u32) -> [BTreeSet<i32>; 2] {
+    let mut neg = BTreeSet::new();
+    let mut pos = BTreeSet::new();
+    for i in -(n1 as i32)..=-1 {
+        neg.insert(i);
+    }
+    for i in 1..=(n2 as i32) {
+        pos.insert(i);
+    }
+    [pos, neg]
+}
+
+macro_rules! set_intersection_bench {
+    ($name: ident, $sets: expr) => {
+        #[bench]
+        pub fn $name(b: &mut Bencher) {
+            // setup
+            let sets = $sets;
+
+            // measure
+            b.iter(|| {
+                let x = sets[0].intersection(&sets[1]).count();
+                black_box(x);
+            })
+        }
+    };
+}
+
+set_intersection_bench! {intersect_random_100,          random(100, 100)}
+set_intersection_bench! {intersect_random_10k,          random(10_000, 10_000)}
+set_intersection_bench! {intersect_random_10_vs_10k,    random(10, 10_000)}
+set_intersection_bench! {intersect_random_10k_vs_10,    random(10_000, 10)}
+set_intersection_bench! {intersect_staggered_100,       staggered(100, 100)}
+set_intersection_bench! {intersect_staggered_10k,       staggered(10_000, 10_000)}
+set_intersection_bench! {intersect_staggered_10_vs_10k, staggered(10, 10_000)}
+set_intersection_bench! {intersect_staggered_10k_vs_10, staggered(10_000, 10)}
+set_intersection_bench! {intersect_neg_vs_pos_100,      neg_vs_pos(100, 100)}
+set_intersection_bench! {intersect_neg_vs_pos_10k,      neg_vs_pos(10_000, 10_000)}
+set_intersection_bench! {intersect_neg_vs_pos_10_vs_10k,neg_vs_pos(10, 10_000)}
+set_intersection_bench! {intersect_neg_vs_pos_10k_vs_10,neg_vs_pos(10_000, 10)}
+set_intersection_bench! {intersect_pos_vs_neg_100,      pos_vs_neg(100, 100)}
+set_intersection_bench! {intersect_pos_vs_neg_10k,      pos_vs_neg(10_000, 10_000)}
+set_intersection_bench! {intersect_pos_vs_neg_10_vs_10k,pos_vs_neg(10, 10_000)}
+set_intersection_bench! {intersect_pos_vs_neg_10k_vs_10,pos_vs_neg(10_000, 10)}
diff --git a/src/liballoc/benches/lib.rs b/src/liballoc/benches/lib.rs
index 08c69ee6e8507..a1884b7d54852 100644
--- a/src/liballoc/benches/lib.rs
+++ b/src/liballoc/benches/lib.rs
@@ -1,5 +1,4 @@
 #![feature(repr_simd)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(test)]
 
 extern crate rand;
diff --git a/src/liballoc/benches/slice.rs b/src/liballoc/benches/slice.rs
index b9ebd74f7999a..f17fb8212ce19 100644
--- a/src/liballoc/benches/slice.rs
+++ b/src/liballoc/benches/slice.rs
@@ -1,8 +1,6 @@
-use rand::{thread_rng};
-use std::mem;
-use std::ptr;
+use std::{mem, ptr};
 
-use rand::{Rng, SeedableRng};
+use rand::{thread_rng, Rng, SeedableRng};
 use rand::distributions::{Standard, Alphanumeric};
 use rand_xorshift::XorShiftRng;
 use test::{Bencher, black_box};
diff --git a/src/liballoc/benches/vec_deque.rs b/src/liballoc/benches/vec_deque.rs
index f7aadbdbd8266..7d2d3cfa61225 100644
--- a/src/liballoc/benches/vec_deque.rs
+++ b/src/liballoc/benches/vec_deque.rs
@@ -45,3 +45,10 @@ fn bench_mut_iter_1000(b: &mut Bencher) {
         black_box(sum);
     })
 }
+
+#[bench]
+fn bench_try_fold(b: &mut Bencher) {
+    let ring: VecDeque<_> = (0..1000).collect();
+
+    b.iter(|| black_box(ring.iter().try_fold(0, |a, b| Some(a + b))))
+}
diff --git a/src/liballoc/benches/vec_deque_append.rs b/src/liballoc/benches/vec_deque_append.rs
index 2db8fbe130907..78ec91d9e3e9b 100644
--- a/src/liballoc/benches/vec_deque_append.rs
+++ b/src/liballoc/benches/vec_deque_append.rs
@@ -1,4 +1,3 @@
-#![cfg_attr(stage0, feature(duration_as_u128))]
 use std::{collections::VecDeque, time::Instant};
 
 const VECDEQUE_LEN: i32 = 100000;
diff --git a/src/liballoc/borrow.rs b/src/liballoc/borrow.rs
index 603d73100a8b4..74c80a08b12ab 100644
--- a/src/liballoc/borrow.rs
+++ b/src/liballoc/borrow.rs
@@ -6,14 +6,14 @@ use core::cmp::Ordering;
 use core::hash::{Hash, Hasher};
 use core::ops::{Add, AddAssign, Deref};
 
-use fmt;
-use string::String;
-
-use self::Cow::*;
-
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::borrow::{Borrow, BorrowMut};
 
+use crate::fmt;
+use crate::string::String;
+
+use Cow::*;
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B>
     where B: ToOwned,
@@ -137,11 +137,11 @@ impl<T> ToOwned for T
 /// ```
 /// use std::borrow::{Cow, ToOwned};
 ///
-/// struct Items<'a, X: 'a> where [X]: ToOwned<Owned=Vec<X>> {
+/// struct Items<'a, X: 'a> where [X]: ToOwned<Owned = Vec<X>> {
 ///     values: Cow<'a, [X]>,
 /// }
 ///
-/// impl<'a, X: Clone + 'a> Items<'a, X> where [X]: ToOwned<Owned=Vec<X>> {
+/// impl<'a, X: Clone + 'a> Items<'a, X> where [X]: ToOwned<Owned = Vec<X>> {
 ///     fn new(v: Cow<'a, [X]>) -> Self {
 ///         Items { values: v }
 ///     }
@@ -182,10 +182,8 @@ pub enum Cow<'a, B: ?Sized + 'a>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Clone for Cow<'a, B>
-    where B: ToOwned
-{
-    fn clone(&self) -> Cow<'a, B> {
+impl<B: ?Sized + ToOwned> Clone for Cow<'_, B> {
+    fn clone(&self) -> Self {
         match *self {
             Borrowed(b) => Borrowed(b),
             Owned(ref o) => {
@@ -195,7 +193,7 @@ impl<'a, B: ?Sized> Clone for Cow<'a, B>
         }
     }
 
-    fn clone_from(&mut self, source: &Cow<'a, B>) {
+    fn clone_from(&mut self, source: &Self) {
         if let Owned(ref mut dest) = *self {
             if let Owned(ref o) = *source {
                 o.borrow().clone_into(dest);
@@ -207,9 +205,7 @@ impl<'a, B: ?Sized> Clone for Cow<'a, B>
     }
 }
 
-impl<'a, B: ?Sized> Cow<'a, B>
-    where B: ToOwned
-{
+impl<B: ?Sized + ToOwned> Cow<'_, B> {
     /// Acquires a mutable reference to the owned form of the data.
     ///
     /// Clones the data if it is not already owned.
@@ -285,9 +281,7 @@ impl<'a, B: ?Sized> Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Deref for Cow<'a, B>
-    where B: ToOwned
-{
+impl<B: ?Sized + ToOwned> Deref for Cow<'_, B> {
     type Target = B;
 
     fn deref(&self) -> &B {
@@ -299,14 +293,14 @@ impl<'a, B: ?Sized> Deref for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Eq for Cow<'a, B> where B: Eq + ToOwned {}
+impl<B: ?Sized> Eq for Cow<'_, B> where B: Eq + ToOwned {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Ord for Cow<'a, B>
+impl<B: ?Sized> Ord for Cow<'_, B>
     where B: Ord + ToOwned
 {
     #[inline]
-    fn cmp(&self, other: &Cow<'a, B>) -> Ordering {
+    fn cmp(&self, other: &Self) -> Ordering {
         Ord::cmp(&**self, &**other)
     }
 }
@@ -333,11 +327,11 @@ impl<'a, B: ?Sized> PartialOrd for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> fmt::Debug for Cow<'a, B>
+impl<B: ?Sized> fmt::Debug for Cow<'_, B>
     where B: fmt::Debug + ToOwned,
           <B as ToOwned>::Owned: fmt::Debug
 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Borrowed(ref b) => fmt::Debug::fmt(b, f),
             Owned(ref o) => fmt::Debug::fmt(o, f),
@@ -346,11 +340,11 @@ impl<'a, B: ?Sized> fmt::Debug for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> fmt::Display for Cow<'a, B>
+impl<B: ?Sized> fmt::Display for Cow<'_, B>
     where B: fmt::Display + ToOwned,
           <B as ToOwned>::Owned: fmt::Display
 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Borrowed(ref b) => fmt::Display::fmt(b, f),
             Owned(ref o) => fmt::Display::fmt(o, f),
@@ -359,18 +353,18 @@ impl<'a, B: ?Sized> fmt::Display for Cow<'a, B>
 }
 
 #[stable(feature = "default", since = "1.11.0")]
-impl<'a, B: ?Sized> Default for Cow<'a, B>
+impl<B: ?Sized> Default for Cow<'_, B>
     where B: ToOwned,
           <B as ToOwned>::Owned: Default
 {
     /// Creates an owned Cow<'a, B> with the default value for the contained owned value.
-    fn default() -> Cow<'a, B> {
+    fn default() -> Self {
         Owned(<B as ToOwned>::Owned::default())
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Hash for Cow<'a, B>
+impl<B: ?Sized> Hash for Cow<'_, B>
     where B: Hash + ToOwned
 {
     #[inline]
@@ -380,8 +374,7 @@ impl<'a, B: ?Sized> Hash for Cow<'a, B>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow(deprecated)]
-impl<'a, T: ?Sized + ToOwned> AsRef<T> for Cow<'a, T> {
+impl<T: ?Sized + ToOwned> AsRef<T> for Cow<'_, T> {
     fn as_ref(&self) -> &T {
         self
     }
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 1c459f5c4250e..0cd2373c7f021 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -71,11 +71,11 @@ use core::ops::{
     CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState
 };
 use core::ptr::{self, NonNull, Unique};
-use core::task::{LocalWaker, Poll};
+use core::task::{Waker, Poll};
 
-use vec::Vec;
-use raw_vec::RawVec;
-use str::from_boxed_utf8_unchecked;
+use crate::vec::Vec;
+use crate::raw_vec::RawVec;
+use crate::str::from_boxed_utf8_unchecked;
 
 /// A pointer type for heap allocation.
 ///
@@ -202,10 +202,15 @@ impl<T: ?Sized> Box<T> {
     #[unstable(feature = "ptr_internals", issue = "0", reason = "use into_raw_non_null instead")]
     #[inline]
     #[doc(hidden)]
-    pub fn into_unique(b: Box<T>) -> Unique<T> {
-        let unique = b.0;
+    pub fn into_unique(mut b: Box<T>) -> Unique<T> {
+        // Box is kind-of a library type, but recognized as a "unique pointer" by
+        // Stacked Borrows.  This function here corresponds to "reborrowing to
+        // a raw pointer", but there is no actual reborrow here -- so
+        // without some care, the pointer we are returning here still carries
+        // the `Uniq` tag.  We round-trip through a mutable reference to avoid that.
+        let unique = unsafe { b.0.as_mut() as *mut T };
         mem::forget(b);
-        unique
+        unsafe { Unique::new_unchecked(unique) }
     }
 
     /// Consumes and leaks the `Box`, returning a mutable reference,
@@ -603,21 +608,21 @@ impl Box<dyn Any + Send> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Display + ?Sized> fmt::Display for Box<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Debug + ?Sized> fmt::Debug for Box<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> fmt::Pointer for Box<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // It's not possible to extract the inner Uniq directly from the Box,
         // instead we cast it to a *const which aliases the Unique
         let ptr: *const T = &**self;
@@ -737,7 +742,7 @@ impl<A, F> FnBox<A> for F
 
 #[unstable(feature = "fnbox",
            reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")]
-impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + 'a> {
+impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + '_> {
     type Output = R;
 
     extern "rust-call" fn call_once(self, args: A) -> R {
@@ -747,7 +752,7 @@ impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + 'a> {
 
 #[unstable(feature = "fnbox",
            reason = "will be deprecated if and when `Box<FnOnce>` becomes usable", issue = "28796")]
-impl<'a, A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + Send + 'a> {
+impl<A, R> FnOnce<A> for Box<dyn FnBox<A, Output = R> + Send + '_> {
     type Output = R;
 
     extern "rust-call" fn call_once(self, args: A) -> R {
@@ -873,13 +878,22 @@ impl<T: ?Sized> AsMut<T> for Box<T> {
 impl<T: ?Sized> Unpin for Box<T> { }
 
 #[unstable(feature = "generator_trait", issue = "43122")]
-impl<T> Generator for Box<T>
-    where T: Generator + ?Sized
-{
-    type Yield = T::Yield;
-    type Return = T::Return;
-    unsafe fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return> {
-        (**self).resume()
+impl<G: ?Sized + Generator + Unpin> Generator for Box<G> {
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume(Pin::new(&mut *self))
+    }
+}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator> Generator for Pin<Box<G>> {
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume((*self).as_mut())
     }
 }
 
@@ -887,7 +901,7 @@ impl<T> Generator for Box<T>
 impl<F: ?Sized + Future + Unpin> Future for Box<F> {
     type Output = F::Output;
 
-    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        F::poll(Pin::new(&mut *self), lw)
+    fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        F::poll(Pin::new(&mut *self), waker)
     }
 }
diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index ad544e6015e4a..ccd4e9dbc0483 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -151,8 +151,8 @@ use core::mem::{swap, size_of, ManuallyDrop};
 use core::ptr;
 use core::fmt;
 
-use slice;
-use vec::{self, Vec};
+use crate::slice;
+use crate::vec::{self, Vec};
 
 use super::SpecExtend;
 
@@ -227,8 +227,8 @@ pub struct PeekMut<'a, T: 'a + Ord> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: Ord + fmt::Debug> fmt::Debug for PeekMut<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: Ord + fmt::Debug> fmt::Debug for PeekMut<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("PeekMut")
          .field(&self.heap.data[0])
          .finish()
@@ -236,7 +236,7 @@ impl<'a, T: Ord + fmt::Debug> fmt::Debug for PeekMut<'a, T> {
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> Drop for PeekMut<'a, T> {
+impl<T: Ord> Drop for PeekMut<'_, T> {
     fn drop(&mut self) {
         if self.sift {
             self.heap.sift_down(0);
@@ -245,17 +245,21 @@ impl<'a, T: Ord> Drop for PeekMut<'a, T> {
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> Deref for PeekMut<'a, T> {
+impl<T: Ord> Deref for PeekMut<'_, T> {
     type Target = T;
     fn deref(&self) -> &T {
-        &self.heap.data[0]
+        debug_assert!(!self.heap.is_empty());
+        // SAFE: PeekMut is only instantiated for non-empty heaps
+        unsafe { self.heap.data.get_unchecked(0) }
     }
 }
 
 #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-impl<'a, T: Ord> DerefMut for PeekMut<'a, T> {
+impl<T: Ord> DerefMut for PeekMut<'_, T> {
     fn deref_mut(&mut self) -> &mut T {
-        &mut self.heap.data[0]
+        debug_assert!(!self.heap.is_empty());
+        // SAFE: PeekMut is only instantiated for non-empty heaps
+        unsafe { self.heap.data.get_unchecked_mut(0) }
     }
 }
 
@@ -291,7 +295,7 @@ impl<T: Ord> Default for BinaryHeap<T> {
 
 #[stable(feature = "binaryheap_debug", since = "1.4.0")]
 impl<T: fmt::Debug + Ord> fmt::Debug for BinaryHeap<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.iter()).finish()
     }
 }
@@ -349,7 +353,7 @@ impl<T: Ord> BinaryHeap<T> {
     /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<T> {
+    pub fn iter(&self) -> Iter<'_, T> {
         Iter { iter: self.data.iter() }
     }
 
@@ -400,7 +404,7 @@ impl<T: Ord> BinaryHeap<T> {
     /// assert_eq!(heap.peek(), Some(&2));
     /// ```
     #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
-    pub fn peek_mut(&mut self) -> Option<PeekMut<T>> {
+    pub fn peek_mut(&mut self) -> Option<PeekMut<'_, T>> {
         if self.is_empty() {
             None
         } else {
@@ -761,7 +765,7 @@ impl<T: Ord> BinaryHeap<T> {
     /// ```
     #[inline]
     #[stable(feature = "drain", since = "1.6.0")]
-    pub fn drain(&mut self) -> Drain<T> {
+    pub fn drain(&mut self) -> Drain<'_, T> {
         Drain { iter: self.data.drain(..) }
     }
 
@@ -859,13 +863,14 @@ struct Hole<'a, T: 'a> {
 }
 
 impl<'a, T> Hole<'a, T> {
-    /// Create a new Hole at index `pos`.
+    /// Create a new `Hole` at index `pos`.
     ///
     /// Unsafe because pos must be within the data slice.
     #[inline]
     unsafe fn new(data: &'a mut [T], pos: usize) -> Self {
         debug_assert!(pos < data.len());
-        let elt = ptr::read(&data[pos]);
+        // SAFE: pos should be inside the slice
+        let elt = ptr::read(data.get_unchecked(pos));
         Hole {
             data,
             elt: ManuallyDrop::new(elt),
@@ -908,7 +913,7 @@ impl<'a, T> Hole<'a, T> {
     }
 }
 
-impl<'a, T> Drop for Hole<'a, T> {
+impl<T> Drop for Hole<'_, T> {
     #[inline]
     fn drop(&mut self) {
         // fill the hole again
@@ -932,8 +937,8 @@ pub struct Iter<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Iter")
          .field(&self.iter.as_slice())
          .finish()
@@ -942,8 +947,8 @@ impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }
@@ -972,14 +977,14 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for Iter<'a, T> {
+impl<T> ExactSizeIterator for Iter<'_, T> {
     fn is_empty(&self) -> bool {
         self.iter.is_empty()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Iter<'a, T> {}
+impl<T> FusedIterator for Iter<'_, T> {}
 
 /// An owning iterator over the elements of a `BinaryHeap`.
 ///
@@ -996,7 +1001,7 @@ pub struct IntoIter<T> {
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("IntoIter")
          .field(&self.iter.as_slice())
          .finish()
@@ -1050,7 +1055,7 @@ pub struct Drain<'a, T: 'a> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> Iterator for Drain<'a, T> {
+impl<T> Iterator for Drain<'_, T> {
     type Item = T;
 
     #[inline]
@@ -1065,7 +1070,7 @@ impl<'a, T: 'a> Iterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
+impl<T> DoubleEndedIterator for Drain<'_, T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> {
         self.iter.next_back()
@@ -1073,14 +1078,14 @@ impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {
+impl<T> ExactSizeIterator for Drain<'_, T> {
     fn is_empty(&self) -> bool {
         self.iter.is_empty()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
+impl<T> FusedIterator for Drain<'_, T> {}
 
 #[stable(feature = "binary_heap_extras_15", since = "1.5.0")]
 impl<T: Ord> From<Vec<T>> for BinaryHeap<T> {
diff --git a/src/liballoc/collections/btree/map.rs b/src/liballoc/collections/btree/map.rs
index 717650aca9600..ce29978856ffd 100644
--- a/src/liballoc/collections/btree/map.rs
+++ b/src/liballoc/collections/btree/map.rs
@@ -1,23 +1,18 @@
+use core::borrow::Borrow;
 use core::cmp::Ordering;
 use core::fmt::Debug;
 use core::hash::{Hash, Hasher};
 use core::iter::{FromIterator, Peekable, FusedIterator};
 use core::marker::PhantomData;
 use core::ops::Bound::{Excluded, Included, Unbounded};
-use core::ops::Index;
-use core::ops::RangeBounds;
+use core::ops::{Index, RangeBounds};
 use core::{fmt, intrinsics, mem, ptr};
 
-use borrow::Borrow;
+use super::node::{self, Handle, NodeRef, marker, InsertResult::*, ForceResult::*};
+use super::search::{self, SearchResult::*};
 
-use super::node::{self, Handle, NodeRef, marker};
-use super::search;
-
-use super::node::InsertResult::*;
-use super::node::ForceResult::*;
-use super::search::SearchResult::*;
-use self::UnderflowResult::*;
-use self::Entry::*;
+use UnderflowResult::*;
+use Entry::*;
 
 /// A map based on a B-Tree.
 ///
@@ -248,7 +243,7 @@ impl<K, Q: ?Sized> super::Recover<Q> for BTreeMap<K, ()>
 
     fn replace(&mut self, key: K) -> Option<K> {
         self.ensure_root_is_owned();
-        match search::search_tree::<marker::Mut, K, (), K>(self.root.as_mut(), &key) {
+        match search::search_tree::<marker::Mut<'_>, K, (), K>(self.root.as_mut(), &key) {
             Found(handle) => Some(mem::replace(handle.into_kv_mut().0, key)),
             GoDown(handle) => {
                 VacantEntry {
@@ -278,8 +273,8 @@ pub struct Iter<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Iter<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Iter<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
 }
@@ -314,7 +309,7 @@ pub struct IntoIter<K, V> {
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
 impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IntoIter<K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let range = Range {
             front: self.front.reborrow(),
             back: self.back.reborrow(),
@@ -336,8 +331,8 @@ pub struct Keys<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a> fmt::Debug for Keys<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: fmt::Debug, V> fmt::Debug for Keys<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
 }
@@ -355,8 +350,8 @@ pub struct Values<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a, V: 'a + fmt::Debug> fmt::Debug for Values<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K, V: fmt::Debug> fmt::Debug for Values<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
 }
@@ -388,8 +383,8 @@ pub struct Range<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for Range<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for Range<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
 }
@@ -411,8 +406,8 @@ pub struct RangeMut<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, K: 'a + fmt::Debug, V: 'a + fmt::Debug> fmt::Debug for RangeMut<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for RangeMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let range = Range {
             front: self.front.reborrow(),
             back: self.back.reborrow(),
@@ -441,8 +436,8 @@ pub enum Entry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a + Debug> Debug for Entry<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: Debug + Ord, V: Debug> Debug for Entry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Vacant(ref v) => f.debug_tuple("Entry")
                               .field(v)
@@ -469,8 +464,8 @@ pub struct VacantEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a> Debug for VacantEntry<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: Debug + Ord, V> Debug for VacantEntry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("VacantEntry")
          .field(self.key())
          .finish()
@@ -492,8 +487,8 @@ pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_btree_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug + Ord, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<K: Debug + Ord, V: Debug> Debug for OccupiedEntry<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("OccupiedEntry")
          .field("key", self.key())
          .field("value", self.get())
@@ -817,7 +812,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// assert_eq!(Some((&5, &"b")), map.range(4..).next());
     /// ```
     #[stable(feature = "btree_range", since = "1.17.0")]
-    pub fn range<T: ?Sized, R>(&self, range: R) -> Range<K, V>
+    pub fn range<T: ?Sized, R>(&self, range: R) -> Range<'_, K, V>
         where T: Ord, K: Borrow<T>, R: RangeBounds<T>
     {
         let root1 = self.root.as_ref();
@@ -858,7 +853,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// }
     /// ```
     #[stable(feature = "btree_range", since = "1.17.0")]
-    pub fn range_mut<T: ?Sized, R>(&mut self, range: R) -> RangeMut<K, V>
+    pub fn range_mut<T: ?Sized, R>(&mut self, range: R) -> RangeMut<'_, K, V>
         where T: Ord, K: Borrow<T>, R: RangeBounds<T>
     {
         let root1 = self.root.as_mut();
@@ -891,7 +886,7 @@ impl<K: Ord, V> BTreeMap<K, V> {
     /// assert_eq!(count["a"], 3);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn entry(&mut self, key: K) -> Entry<K, V> {
+    pub fn entry(&mut self, key: K) -> Entry<'_, K, V> {
         // FIXME(@porglezomp) Avoid allocating if we don't insert
         self.ensure_root_is_owned();
         match search::search_tree(self.root.as_mut(), &key) {
@@ -1201,7 +1196,7 @@ impl<'a, K: 'a, V: 'a> Iterator for Iter<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
+impl<K, V> FusedIterator for Iter<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> {
@@ -1216,15 +1211,15 @@ impl<'a, K: 'a, V: 'a> DoubleEndedIterator for Iter<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     fn len(&self) -> usize {
         self.length
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter {
             range: self.range.clone(),
             length: self.length,
@@ -1273,14 +1268,14 @@ impl<'a, K: 'a, V: 'a> DoubleEndedIterator for IterMut<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: 'a, V: 'a> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     fn len(&self) -> usize {
         self.length
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
+impl<K, V> FusedIterator for IterMut<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<K, V> IntoIterator for BTreeMap<K, V> {
@@ -1436,18 +1431,18 @@ impl<'a, K, V> DoubleEndedIterator for Keys<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
+impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
+impl<K, V> FusedIterator for Keys<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Keys<'a, K, V> {
-    fn clone(&self) -> Keys<'a, K, V> {
+impl<K, V> Clone for Keys<'_, K, V> {
+    fn clone(&self) -> Self {
         Keys { inner: self.inner.clone() }
     }
 }
@@ -1473,18 +1468,18 @@ impl<'a, K, V> DoubleEndedIterator for Values<'a, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
+impl<K, V> ExactSizeIterator for Values<'_, K, V> {
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
+impl<K, V> FusedIterator for Values<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Values<'a, K, V> {
-    fn clone(&self) -> Values<'a, K, V> {
+impl<K, V> Clone for Values<'_, K, V> {
+    fn clone(&self) -> Self {
         Values { inner: self.inner.clone() }
     }
 }
@@ -1523,15 +1518,14 @@ impl<'a, K, V> DoubleEndedIterator for ValuesMut<'a, K, V> {
 }
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
-impl<'a, K, V> ExactSizeIterator for ValuesMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
-
+impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
 
 impl<'a, K, V> Range<'a, K, V> {
     unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) {
@@ -1609,11 +1603,11 @@ impl<'a, K, V> Range<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Range<'a, K, V> {}
+impl<K, V> FusedIterator for Range<'_, K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
-impl<'a, K, V> Clone for Range<'a, K, V> {
-    fn clone(&self) -> Range<'a, K, V> {
+impl<K, V> Clone for Range<'_, K, V> {
+    fn clone(&self) -> Self {
         Range {
             front: self.front,
             back: self.back,
@@ -1640,9 +1634,11 @@ impl<'a, K, V> RangeMut<'a, K, V> {
 
         let mut cur_handle = match handle.right_kv() {
             Ok(kv) => {
-                let (k, v) = ptr::read(&kv).into_kv_mut();
-                self.front = kv.right_edge();
-                return (k, v);
+                self.front = ptr::read(&kv).right_edge();
+                // Doing the descend invalidates the references returned by `into_kv_mut`,
+                // so we have to do this last.
+                let (k, v) = kv.into_kv_mut();
+                return (k, v); // coerce k from `&mut K` to `&K`
             }
             Err(last_edge) => {
                 let next_level = last_edge.into_node().ascend().ok();
@@ -1653,9 +1649,11 @@ impl<'a, K, V> RangeMut<'a, K, V> {
         loop {
             match cur_handle.right_kv() {
                 Ok(kv) => {
-                    let (k, v) = ptr::read(&kv).into_kv_mut();
-                    self.front = first_leaf_edge(kv.right_edge().descend());
-                    return (k, v);
+                    self.front = first_leaf_edge(ptr::read(&kv).right_edge().descend());
+                    // Doing the descend invalidates the references returned by `into_kv_mut`,
+                    // so we have to do this last.
+                    let (k, v) = kv.into_kv_mut();
+                    return (k, v); // coerce k from `&mut K` to `&K`
                 }
                 Err(last_edge) => {
                     let next_level = last_edge.into_node().ascend().ok();
@@ -1678,7 +1676,7 @@ impl<'a, K, V> DoubleEndedIterator for RangeMut<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for RangeMut<'a, K, V> {}
+impl<K, V> FusedIterator for RangeMut<'_, K, V> {}
 
 impl<'a, K, V> RangeMut<'a, K, V> {
     unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a mut V) {
@@ -1686,9 +1684,11 @@ impl<'a, K, V> RangeMut<'a, K, V> {
 
         let mut cur_handle = match handle.left_kv() {
             Ok(kv) => {
-                let (k, v) = ptr::read(&kv).into_kv_mut();
-                self.back = kv.left_edge();
-                return (k, v);
+                self.back = ptr::read(&kv).left_edge();
+                // Doing the descend invalidates the references returned by `into_kv_mut`,
+                // so we have to do this last.
+                let (k, v) = kv.into_kv_mut();
+                return (k, v); // coerce k from `&mut K` to `&K`
             }
             Err(last_edge) => {
                 let next_level = last_edge.into_node().ascend().ok();
@@ -1699,9 +1699,11 @@ impl<'a, K, V> RangeMut<'a, K, V> {
         loop {
             match cur_handle.left_kv() {
                 Ok(kv) => {
-                    let (k, v) = ptr::read(&kv).into_kv_mut();
-                    self.back = last_leaf_edge(kv.left_edge().descend());
-                    return (k, v);
+                    self.back = last_leaf_edge(ptr::read(&kv).left_edge().descend());
+                    // Doing the descend invalidates the references returned by `into_kv_mut`,
+                    // so we have to do this last.
+                    let (k, v) = kv.into_kv_mut();
+                    return (k, v); // coerce k from `&mut K` to `&K`
                 }
                 Err(last_edge) => {
                     let next_level = last_edge.into_node().ascend().ok();
@@ -1783,13 +1785,13 @@ impl<K: Ord, V: Ord> Ord for BTreeMap<K, V> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<K: Debug, V: Debug> Debug for BTreeMap<K, V> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_map().entries(self.iter()).finish()
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K: Ord, Q: ?Sized, V> Index<&'a Q> for BTreeMap<K, V>
+impl<K: Ord, Q: ?Sized, V> Index<&Q> for BTreeMap<K, V>
     where K: Borrow<Q>,
           Q: Ord
 {
@@ -1940,7 +1942,7 @@ impl<K, V> BTreeMap<K, V> {
     /// assert_eq!((*first_key, *first_value), (1, "a"));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<K, V> {
+    pub fn iter(&self) -> Iter<'_, K, V> {
         Iter {
             range: Range {
                 front: first_leaf_edge(self.root.as_ref()),
@@ -1972,7 +1974,7 @@ impl<K, V> BTreeMap<K, V> {
     /// }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter_mut(&mut self) -> IterMut<K, V> {
+    pub fn iter_mut(&mut self) -> IterMut<'_, K, V> {
         let root1 = self.root.as_mut();
         let root2 = unsafe { ptr::read(&root1) };
         IterMut {
@@ -2049,7 +2051,7 @@ impl<K, V> BTreeMap<K, V> {
     ///                     String::from("goodbye!")]);
     /// ```
     #[stable(feature = "map_values_mut", since = "1.10.0")]
-    pub fn values_mut(&mut self) -> ValuesMut<K, V> {
+    pub fn values_mut(&mut self) -> ValuesMut<'_, K, V> {
         ValuesMut { inner: self.iter_mut() }
     }
 
@@ -2374,7 +2376,7 @@ impl<'a, K: Ord, V> OccupiedEntry<'a, K, V> {
 
     /// Gets a mutable reference to the value in the entry.
     ///
-    /// If you need a reference to the `OccupiedEntry` which may outlive the
+    /// If you need a reference to the `OccupiedEntry` that may outlive the
     /// destruction of the `Entry` value, see [`into_mut`].
     ///
     /// [`into_mut`]: #method.into_mut
diff --git a/src/liballoc/collections/btree/node.rs b/src/liballoc/collections/btree/node.rs
index f9a21aa95db71..66d619b1298b4 100644
--- a/src/liballoc/collections/btree/node.rs
+++ b/src/liballoc/collections/btree/node.rs
@@ -36,8 +36,8 @@ use core::mem::{self, MaybeUninit};
 use core::ptr::{self, Unique, NonNull};
 use core::slice;
 
-use alloc::{Global, Alloc, Layout};
-use boxed::Box;
+use crate::alloc::{Global, Alloc, Layout};
+use crate::boxed::Box;
 
 const B: usize = 6;
 pub const MIN_LEN: usize = B - 1;
@@ -50,11 +50,11 @@ pub const CAPACITY: usize = 2 * B - 1;
 ///
 /// We have a separate type for the header and rely on it matching the prefix of `LeafNode`, in
 /// order to statically allocate a single dummy node to avoid allocations. This struct is
-/// `repr(C)` to prevent them from being reordered.  `LeafNode` does not just contain a
+/// `repr(C)` to prevent them from being reordered. `LeafNode` does not just contain a
 /// `NodeHeader` because we do not want unnecessary padding between `len` and the keys.
-/// Crucially, `NodeHeader` can be safely transmuted to different K and V.  (This is exploited
+/// Crucially, `NodeHeader` can be safely transmuted to different K and V. (This is exploited
 /// by `as_header`.)
-/// See `into_key_slice` for an explanation of K2.  K2 cannot be safely transmuted around
+/// See `into_key_slice` for an explanation of K2. K2 cannot be safely transmuted around
 /// because the size of `NodeHeader` depends on its alignment!
 #[repr(C)]
 struct NodeHeader<K, V, K2 = ()> {
@@ -95,8 +95,8 @@ struct LeafNode<K, V> {
 
     /// The arrays storing the actual data of the node. Only the first `len` elements of each
     /// array are initialized and valid.
-    keys: MaybeUninit<[K; CAPACITY]>,
-    vals: MaybeUninit<[V; CAPACITY]>,
+    keys: [MaybeUninit<K>; CAPACITY],
+    vals: [MaybeUninit<V>; CAPACITY],
 }
 
 impl<K, V> LeafNode<K, V> {
@@ -106,8 +106,8 @@ impl<K, V> LeafNode<K, V> {
         LeafNode {
             // As a general policy, we leave fields uninitialized if they can be, as this should
             // be both slightly faster and easier to track in Valgrind.
-            keys: MaybeUninit::uninitialized(),
-            vals: MaybeUninit::uninitialized(),
+            keys: uninitialized_array![_; CAPACITY],
+            vals: uninitialized_array![_; CAPACITY],
             parent: ptr::null(),
             parent_idx: MaybeUninit::uninitialized(),
             len: 0
@@ -145,7 +145,7 @@ struct InternalNode<K, V> {
 
     /// The pointers to the children of this node. `len + 1` of these are considered
     /// initialized and valid.
-    edges: [BoxedNode<K, V>; 2 * B],
+    edges: [MaybeUninit<BoxedNode<K, V>>; 2 * B],
 }
 
 impl<K, V> InternalNode<K, V> {
@@ -159,7 +159,7 @@ impl<K, V> InternalNode<K, V> {
     unsafe fn new() -> Self {
         InternalNode {
             data: LeafNode::new(),
-            edges: mem::uninitialized()
+            edges: uninitialized_array![_; 2*B],
         }
     }
 }
@@ -226,7 +226,7 @@ impl<K, V> Root<K, V> {
     }
 
     pub fn as_ref(&self)
-            -> NodeRef<marker::Immut, K, V, marker::LeafOrInternal> {
+            -> NodeRef<marker::Immut<'_>, K, V, marker::LeafOrInternal> {
         NodeRef {
             height: self.height,
             node: self.node.as_ptr(),
@@ -236,7 +236,7 @@ impl<K, V> Root<K, V> {
     }
 
     pub fn as_mut(&mut self)
-            -> NodeRef<marker::Mut, K, V, marker::LeafOrInternal> {
+            -> NodeRef<marker::Mut<'_>, K, V, marker::LeafOrInternal> {
         NodeRef {
             height: self.height,
             node: self.node.as_ptr(),
@@ -258,10 +258,10 @@ impl<K, V> Root<K, V> {
     /// Adds a new internal node with a single edge, pointing to the previous root, and make that
     /// new node the root. This increases the height by 1 and is the opposite of `pop_level`.
     pub fn push_level(&mut self)
-            -> NodeRef<marker::Mut, K, V, marker::Internal> {
+            -> NodeRef<marker::Mut<'_>, K, V, marker::Internal> {
         debug_assert!(!self.is_shared_root());
         let mut new_node = Box::new(unsafe { InternalNode::new() });
-        new_node.edges[0] = unsafe { BoxedNode::from_ptr(self.node.as_ptr()) };
+        new_node.edges[0].set(unsafe { BoxedNode::from_ptr(self.node.as_ptr()) });
 
         self.node = BoxedNode::from_internal(new_node);
         self.height += 1;
@@ -453,7 +453,7 @@ impl<BorrowType, K, V, Type> NodeRef<BorrowType, K, V, Type> {
                     root: self.root,
                     _marker: PhantomData
                 },
-                idx: unsafe { usize::from(*self.as_header().parent_idx.get_ref()) },
+                idx: unsafe { usize::from(*self.as_header().parent_idx.as_ptr()) },
                 _marker: PhantomData
             })
         } else {
@@ -531,7 +531,7 @@ impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
     /// Unsafely asserts to the compiler some static information about whether this
     /// node is a `Leaf`.
     unsafe fn cast_unchecked<NewType>(&mut self)
-            -> NodeRef<marker::Mut, K, V, NewType> {
+            -> NodeRef<marker::Mut<'_>, K, V, NewType> {
 
         NodeRef {
             height: self.height,
@@ -551,7 +551,7 @@ impl<'a, K, V, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
     /// of a reborrowed handle, out of bounds.
     // FIXME(@gereeter) consider adding yet another type parameter to `NodeRef` that restricts
     // the use of `ascend` and `into_root_mut` on reborrowed pointers, preventing this unsafety.
-    unsafe fn reborrow_mut(&mut self) -> NodeRef<marker::Mut, K, V, Type> {
+    unsafe fn reborrow_mut(&mut self) -> NodeRef<marker::Mut<'_>, K, V, Type> {
         NodeRef {
             height: self.height,
             node: self.node,
@@ -623,7 +623,7 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Immut<'a>, K, V, Type> {
         // We cannot be the root, so `as_leaf` is okay
         unsafe {
             slice::from_raw_parts(
-                self.as_leaf().vals.as_ptr() as *const V,
+                MaybeUninit::first_ptr(&self.as_leaf().vals),
                 self.len()
             )
         }
@@ -645,12 +645,14 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
     }
 
     fn into_key_slice_mut(mut self) -> &'a mut [K] {
+        // Same as for `into_key_slice` above, we try to avoid a run-time check
+        // (the alignment comparison will usually be performed at compile-time).
         if mem::align_of::<K>() > mem::align_of::<LeafNode<(), ()>>() && self.is_shared_root() {
             &mut []
         } else {
             unsafe {
                 slice::from_raw_parts_mut(
-                    (*self.as_leaf_mut()).keys.as_mut_ptr() as *mut K,
+                    MaybeUninit::first_ptr_mut(&mut (*self.as_leaf_mut()).keys),
                     self.len()
                 )
             }
@@ -661,15 +663,32 @@ impl<'a, K: 'a, V: 'a, Type> NodeRef<marker::Mut<'a>, K, V, Type> {
         debug_assert!(!self.is_shared_root());
         unsafe {
             slice::from_raw_parts_mut(
-                (*self.as_leaf_mut()).vals.as_mut_ptr() as *mut V,
+                MaybeUninit::first_ptr_mut(&mut (*self.as_leaf_mut()).vals),
                 self.len()
             )
         }
     }
 
-    fn into_slices_mut(self) -> (&'a mut [K], &'a mut [V]) {
-        let k = unsafe { ptr::read(&self) };
-        (k.into_key_slice_mut(), self.into_val_slice_mut())
+    fn into_slices_mut(mut self) -> (&'a mut [K], &'a mut [V]) {
+        debug_assert!(!self.is_shared_root());
+        // We cannot use the getters here, because calling the second one
+        // invalidates the reference returned by the first.
+        // More precisely, it is the call to `len` that is the culprit,
+        // because that creates a shared reference to the header, which *can*
+        // overlap with the keys (and even the values, for ZST keys).
+        unsafe {
+            let len = self.len();
+            let leaf = self.as_leaf_mut();
+            let keys = slice::from_raw_parts_mut(
+                MaybeUninit::first_ptr_mut(&mut (*leaf).keys),
+                len
+            );
+            let vals = slice::from_raw_parts_mut(
+                MaybeUninit::first_ptr_mut(&mut (*leaf).vals),
+                len
+            );
+            (keys, vals)
+        }
     }
 }
 
@@ -718,7 +737,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
         unsafe {
             ptr::write(self.keys_mut().get_unchecked_mut(idx), key);
             ptr::write(self.vals_mut().get_unchecked_mut(idx), val);
-            ptr::write(self.as_internal_mut().edges.get_unchecked_mut(idx + 1), edge.node);
+            self.as_internal_mut().edges.get_unchecked_mut(idx + 1).set(edge.node);
 
             (*self.as_leaf_mut()).len += 1;
 
@@ -749,7 +768,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::Internal> {
             slice_insert(self.vals_mut(), 0, val);
             slice_insert(
                 slice::from_raw_parts_mut(
-                    self.as_internal_mut().edges.as_mut_ptr(),
+                    MaybeUninit::first_ptr_mut(&mut self.as_internal_mut().edges),
                     self.len()+1
                 ),
                 0,
@@ -778,7 +797,9 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
             let edge = match self.reborrow_mut().force() {
                 ForceResult::Leaf(_) => None,
                 ForceResult::Internal(internal) => {
-                    let edge = ptr::read(internal.as_internal().edges.get_unchecked(idx + 1));
+                    let edge = ptr::read(
+                        internal.as_internal().edges.get_unchecked(idx + 1).as_ptr()
+                    );
                     let mut new_root = Root { node: edge, height: internal.height - 1 };
                     (*new_root.as_mut().as_leaf_mut()).parent = ptr::null();
                     Some(new_root)
@@ -806,7 +827,7 @@ impl<'a, K, V> NodeRef<marker::Mut<'a>, K, V, marker::LeafOrInternal> {
                 ForceResult::Internal(mut internal) => {
                     let edge = slice_remove(
                         slice::from_raw_parts_mut(
-                            internal.as_internal_mut().edges.as_mut_ptr(),
+                            MaybeUninit::first_ptr_mut(&mut internal.as_internal_mut().edges),
                             old_len+1
                         ),
                         0
@@ -926,7 +947,7 @@ impl<BorrowType, K, V, NodeType, HandleType>
 
     /// Temporarily takes out another, immutable handle on the same location.
     pub fn reborrow(&self)
-            -> Handle<NodeRef<marker::Immut, K, V, NodeType>, HandleType> {
+            -> Handle<NodeRef<marker::Immut<'_>, K, V, NodeType>, HandleType> {
 
         // We can't use Handle::new_kv or Handle::new_edge because we don't know our type
         Handle {
@@ -951,7 +972,7 @@ impl<'a, K, V, NodeType, HandleType>
     // FIXME(@gereeter) consider adding yet another type parameter to `NodeRef` that restricts
     // the use of `ascend` and `into_root_mut` on reborrowed pointers, preventing this unsafety.
     pub unsafe fn reborrow_mut(&mut self)
-            -> Handle<NodeRef<marker::Mut, K, V, NodeType>, HandleType> {
+            -> Handle<NodeRef<marker::Mut<'_>, K, V, NodeType>, HandleType> {
 
         // We can't use Handle::new_kv or Handle::new_edge because we don't know our type
         Handle {
@@ -1066,7 +1087,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
     /// Unsafely asserts to the compiler some static information about whether the underlying
     /// node of this handle is a `Leaf`.
     unsafe fn cast_unchecked<NewType>(&mut self)
-            -> Handle<NodeRef<marker::Mut, K, V, NewType>, marker::Edge> {
+            -> Handle<NodeRef<marker::Mut<'_>, K, V, NewType>, marker::Edge> {
 
         Handle::new_edge(self.node.cast_unchecked(), self.idx)
     }
@@ -1085,7 +1106,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
 
             slice_insert(
                 slice::from_raw_parts_mut(
-                    self.node.as_internal_mut().edges.as_mut_ptr(),
+                    MaybeUninit::first_ptr_mut(&mut self.node.as_internal_mut().edges),
                     self.node.len()
                 ),
                 self.idx + 1,
@@ -1140,7 +1161,9 @@ impl<BorrowType, K, V>
     pub fn descend(self) -> NodeRef<BorrowType, K, V, marker::LeafOrInternal> {
         NodeRef {
             height: self.node.height - 1,
-            node: unsafe { self.node.as_internal().edges.get_unchecked(self.idx).as_ptr() },
+            node: unsafe {
+                (&*self.node.as_internal().edges.get_unchecked(self.idx).as_ptr()).as_ptr()
+            },
             root: self.node.root,
             _marker: PhantomData
         }
@@ -1291,7 +1314,7 @@ impl<'a, K, V> Handle<NodeRef<marker::Mut<'a>, K, V, marker::Internal>, marker::
         }
     }
 
-    /// Returns whether it is valid to call `.merge()`, i.e., whether there is enough room in
+    /// Returns `true` if it is valid to call `.merge()`, i.e., whether there is enough room in
     /// a node to hold the combination of the nodes to the left and right of this handle along
     /// with the key/value pair at this handle.
     pub fn can_merge(&self) -> bool {
@@ -1554,8 +1577,8 @@ unsafe fn move_kv<K, V>(
 
 // Source and destination must have the same height.
 unsafe fn move_edges<K, V>(
-    mut source: NodeRef<marker::Mut, K, V, marker::Internal>, source_offset: usize,
-    mut dest: NodeRef<marker::Mut, K, V, marker::Internal>, dest_offset: usize,
+    mut source: NodeRef<marker::Mut<'_>, K, V, marker::Internal>, source_offset: usize,
+    mut dest: NodeRef<marker::Mut<'_>, K, V, marker::Internal>, dest_offset: usize,
     count: usize)
 {
     let source_ptr = source.as_internal_mut().edges.as_mut_ptr();
@@ -1569,7 +1592,7 @@ unsafe fn move_edges<K, V>(
 impl<BorrowType, K, V, HandleType>
         Handle<NodeRef<BorrowType, K, V, marker::LeafOrInternal>, HandleType> {
 
-    /// Check whether the underlying node is an `Internal` node or a `Leaf` node.
+    /// Checks whether the underlying node is an `Internal` node or a `Leaf` node.
     pub fn force(self) -> ForceResult<
         Handle<NodeRef<BorrowType, K, V, marker::Leaf>, HandleType>,
         Handle<NodeRef<BorrowType, K, V, marker::Internal>, HandleType>
diff --git a/src/liballoc/collections/btree/search.rs b/src/liballoc/collections/btree/search.rs
index 9010de7c16ac3..dfb67d2ea5756 100644
--- a/src/liballoc/collections/btree/search.rs
+++ b/src/liballoc/collections/btree/search.rs
@@ -1,11 +1,9 @@
+use core::borrow::Borrow;
 use core::cmp::Ordering;
 
-use borrow::Borrow;
+use super::node::{Handle, NodeRef, marker, ForceResult::*};
 
-use super::node::{Handle, NodeRef, marker};
-
-use super::node::ForceResult::*;
-use self::SearchResult::*;
+use SearchResult::*;
 
 pub enum SearchResult<BorrowType, K, V, FoundType, GoDownType> {
     Found(Handle<NodeRef<BorrowType, K, V, FoundType>, marker::KV>),
diff --git a/src/liballoc/collections/btree/set.rs b/src/liballoc/collections/btree/set.rs
index 71fec7da9a5ed..2be6455ad5903 100644
--- a/src/liballoc/collections/btree/set.rs
+++ b/src/liballoc/collections/btree/set.rs
@@ -1,15 +1,14 @@
 // This is pretty much entirely stolen from TreeSet, since BTreeMap has an identical interface
 // to TreeMap
 
+use core::borrow::Borrow;
 use core::cmp::Ordering::{self, Less, Greater, Equal};
 use core::cmp::{min, max};
-use core::fmt::Debug;
-use core::fmt;
+use core::fmt::{self, Debug};
 use core::iter::{Peekable, FromIterator, FusedIterator};
 use core::ops::{BitOr, BitAnd, BitXor, Sub, RangeBounds};
 
-use borrow::Borrow;
-use collections::btree_map::{self, BTreeMap, Keys};
+use crate::collections::btree_map::{self, BTreeMap, Keys};
 use super::Recover;
 
 // FIXME(conventions): implement bounded iterators
@@ -76,8 +75,8 @@ pub struct Iter<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Iter")
          .field(&self.iter.clone())
          .finish()
@@ -124,8 +123,8 @@ pub struct Difference<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Difference<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Difference<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Difference")
          .field(&self.a)
          .field(&self.b)
@@ -147,8 +146,8 @@ pub struct SymmetricDifference<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for SymmetricDifference<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for SymmetricDifference<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("SymmetricDifference")
          .field(&self.a)
          .field(&self.b)
@@ -170,8 +169,8 @@ pub struct Intersection<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Intersection<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Intersection<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Intersection")
          .field(&self.a)
          .field(&self.b)
@@ -193,8 +192,8 @@ pub struct Union<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Union<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Union<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Union")
          .field(&self.a)
          .field(&self.b)
@@ -241,7 +240,7 @@ impl<T: Ord> BTreeSet<T> {
     /// assert_eq!(Some(&5), set.range(4..).next());
     /// ```
     #[stable(feature = "btree_range", since = "1.17.0")]
-    pub fn range<K: ?Sized, R>(&self, range: R) -> Range<T>
+    pub fn range<K: ?Sized, R>(&self, range: R) -> Range<'_, T>
         where K: Ord, T: Borrow<K>, R: RangeBounds<K>
     {
         Range { iter: self.map.range(range) }
@@ -557,7 +556,7 @@ impl<T: Ord> BTreeSet<T> {
         Recover::replace(&mut self.map, value)
     }
 
-    /// Removes a value from the set. Returns `true` if the value was
+    /// Removes a value from the set. Returns whether the value was
     /// present in the set.
     ///
     /// The value may be any borrowed form of the set's value type,
@@ -703,7 +702,7 @@ impl<T> BTreeSet<T> {
     /// assert_eq!(set_iter.next(), None);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<T> {
+    pub fn iter(&self) -> Iter<'_, T> {
         Iter { iter: self.map.keys() }
     }
 
@@ -809,7 +808,7 @@ impl<T: Ord> Default for BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T: Ord + Clone> Sub<&'b BTreeSet<T>> for &'a BTreeSet<T> {
+impl<T: Ord + Clone> Sub<&BTreeSet<T>> for &BTreeSet<T> {
     type Output = BTreeSet<T>;
 
     /// Returns the difference of `self` and `rhs` as a new `BTreeSet<T>`.
@@ -832,7 +831,7 @@ impl<'a, 'b, T: Ord + Clone> Sub<&'b BTreeSet<T>> for &'a BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T: Ord + Clone> BitXor<&'b BTreeSet<T>> for &'a BTreeSet<T> {
+impl<T: Ord + Clone> BitXor<&BTreeSet<T>> for &BTreeSet<T> {
     type Output = BTreeSet<T>;
 
     /// Returns the symmetric difference of `self` and `rhs` as a new `BTreeSet<T>`.
@@ -855,7 +854,7 @@ impl<'a, 'b, T: Ord + Clone> BitXor<&'b BTreeSet<T>> for &'a BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T: Ord + Clone> BitAnd<&'b BTreeSet<T>> for &'a BTreeSet<T> {
+impl<T: Ord + Clone> BitAnd<&BTreeSet<T>> for &BTreeSet<T> {
     type Output = BTreeSet<T>;
 
     /// Returns the intersection of `self` and `rhs` as a new `BTreeSet<T>`.
@@ -878,7 +877,7 @@ impl<'a, 'b, T: Ord + Clone> BitAnd<&'b BTreeSet<T>> for &'a BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T: Ord + Clone> BitOr<&'b BTreeSet<T>> for &'a BTreeSet<T> {
+impl<T: Ord + Clone> BitOr<&BTreeSet<T>> for &BTreeSet<T> {
     type Output = BTreeSet<T>;
 
     /// Returns the union of `self` and `rhs` as a new `BTreeSet<T>`.
@@ -902,14 +901,14 @@ impl<'a, 'b, T: Ord + Clone> BitOr<&'b BTreeSet<T>> for &'a BTreeSet<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Debug> Debug for BTreeSet<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_set().entries(self.iter()).finish()
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }
@@ -931,12 +930,12 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for Iter<'a, T> {
+impl<T> ExactSizeIterator for Iter<'_, T> {
     fn len(&self) -> usize { self.iter.len() }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Iter<'a, T> {}
+impl<T> FusedIterator for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> Iterator for IntoIter<T> {
@@ -964,8 +963,8 @@ impl<T> ExactSizeIterator for IntoIter<T> {
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
-impl<'a, T> Clone for Range<'a, T> {
-    fn clone(&self) -> Range<'a, T> {
+impl<T> Clone for Range<'_, T> {
+    fn clone(&self) -> Self {
         Range { iter: self.iter.clone() }
     }
 }
@@ -987,9 +986,9 @@ impl<'a, T> DoubleEndedIterator for Range<'a, T> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Range<'a, T> {}
+impl<T> FusedIterator for Range<'_, T> {}
 
-/// Compare `x` and `y`, but return `short` if x is None and `long` if y is None
+/// Compares `x` and `y`, but return `short` if x is None and `long` if y is None
 fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>, short: Ordering, long: Ordering) -> Ordering {
     match (x, y) {
         (None, _) => short,
@@ -999,8 +998,8 @@ fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>, short: Ordering, long: Ordering
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Difference<'a, T> {
-    fn clone(&self) -> Difference<'a, T> {
+impl<T> Clone for Difference<'_, T> {
+    fn clone(&self) -> Self {
         Difference {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1034,11 +1033,11 @@ impl<'a, T: Ord> Iterator for Difference<'a, T> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: Ord> FusedIterator for Difference<'a, T> {}
+impl<T: Ord> FusedIterator for Difference<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for SymmetricDifference<'a, T> {
-    fn clone(&self) -> SymmetricDifference<'a, T> {
+impl<T> Clone for SymmetricDifference<'_, T> {
+    fn clone(&self) -> Self {
         SymmetricDifference {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1068,11 +1067,11 @@ impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: Ord> FusedIterator for SymmetricDifference<'a, T> {}
+impl<T: Ord> FusedIterator for SymmetricDifference<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Intersection<'a, T> {
-    fn clone(&self) -> Intersection<'a, T> {
+impl<T> Clone for Intersection<'_, T> {
+    fn clone(&self) -> Self {
         Intersection {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1106,11 +1105,11 @@ impl<'a, T: Ord> Iterator for Intersection<'a, T> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: Ord> FusedIterator for Intersection<'a, T> {}
+impl<T: Ord> FusedIterator for Intersection<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Union<'a, T> {
-    fn clone(&self) -> Union<'a, T> {
+impl<T> Clone for Union<'_, T> {
+    fn clone(&self) -> Self {
         Union {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1140,4 +1139,4 @@ impl<'a, T: Ord> Iterator for Union<'a, T> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: Ord> FusedIterator for Union<'a, T> {}
+impl<T: Ord> FusedIterator for Union<'_, T> {}
diff --git a/src/liballoc/collections/linked_list.rs b/src/liballoc/collections/linked_list.rs
index 804a2e9c8873b..c2ee2e63156cf 100644
--- a/src/liballoc/collections/linked_list.rs
+++ b/src/liballoc/collections/linked_list.rs
@@ -20,7 +20,7 @@ use core::marker::PhantomData;
 use core::mem;
 use core::ptr::NonNull;
 
-use boxed::Box;
+use crate::boxed::Box;
 use super::SpecExtend;
 
 /// A doubly-linked list with owned nodes.
@@ -61,8 +61,8 @@ pub struct Iter<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Iter")
          .field(&self.len)
          .finish()
@@ -71,7 +71,7 @@ impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
     fn clone(&self) -> Self {
         Iter { ..*self }
     }
@@ -93,8 +93,8 @@ pub struct IterMut<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for IterMut<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("IterMut")
          .field(&self.list)
          .field(&self.len)
@@ -117,7 +117,7 @@ pub struct IntoIter<T> {
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("IntoIter")
          .field(&self.list)
          .finish()
@@ -331,7 +331,7 @@ impl<T> LinkedList<T> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<T> {
+    pub fn iter(&self) -> Iter<'_, T> {
         Iter {
             head: self.head,
             tail: self.tail,
@@ -365,7 +365,7 @@ impl<T> LinkedList<T> {
     /// ```
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter_mut(&mut self) -> IterMut<T> {
+    pub fn iter_mut(&mut self) -> IterMut<'_, T> {
         IterMut {
             head: self.head,
             tail: self.tail,
@@ -764,7 +764,7 @@ impl<T> LinkedList<T> {
     /// assert_eq!(odds.into_iter().collect::<Vec<_>>(), vec![1, 3, 5, 9, 11, 13, 15]);
     /// ```
     #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-    pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<T, F>
+    pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F>
         where F: FnMut(&mut T) -> bool
     {
         // avoid borrow issues.
@@ -832,10 +832,10 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for Iter<'a, T> {}
+impl<T> ExactSizeIterator for Iter<'_, T> {}
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Iter<'a, T> {}
+impl<T> FusedIterator for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T> Iterator for IterMut<'a, T> {
@@ -881,12 +881,12 @@ impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for IterMut<'a, T> {}
+impl<T> ExactSizeIterator for IterMut<'_, T> {}
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for IterMut<'a, T> {}
+impl<T> FusedIterator for IterMut<'_, T> {}
 
-impl<'a, T> IterMut<'a, T> {
+impl<T> IterMut<'_, T> {
     /// Inserts the given element just after the element most recently returned by `.next()`.
     /// The inserted element does not appear in the iteration.
     ///
@@ -982,7 +982,7 @@ pub struct DrainFilter<'a, T: 'a, F: 'a>
 }
 
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<'a, T, F> Iterator for DrainFilter<'a, T, F>
+impl<T, F> Iterator for DrainFilter<'_, T, F>
     where F: FnMut(&mut T) -> bool,
 {
     type Item = T;
@@ -1009,7 +1009,7 @@ impl<'a, T, F> Iterator for DrainFilter<'a, T, F>
 }
 
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<'a, T, F> Drop for DrainFilter<'a, T, F>
+impl<T, F> Drop for DrainFilter<'_, T, F>
     where F: FnMut(&mut T) -> bool,
 {
     fn drop(&mut self) {
@@ -1018,10 +1018,10 @@ impl<'a, T, F> Drop for DrainFilter<'a, T, F>
 }
 
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<'a, T: 'a + fmt::Debug, F> fmt::Debug for DrainFilter<'a, T, F>
+impl<T: fmt::Debug, F> fmt::Debug for DrainFilter<'_, T, F>
     where F: FnMut(&mut T) -> bool
 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("DrainFilter")
          .field(&self.list)
          .finish()
@@ -1164,7 +1164,7 @@ impl<T: Clone> Clone for LinkedList<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Debug> fmt::Debug for LinkedList<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self).finish()
     }
 }
@@ -1200,16 +1200,16 @@ unsafe impl<T: Send> Send for LinkedList<T> {}
 unsafe impl<T: Sync> Sync for LinkedList<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Send for Iter<'a, T> {}
+unsafe impl<T: Sync> Send for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Sync for Iter<'a, T> {}
+unsafe impl<T: Sync> Sync for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Send> Send for IterMut<'a, T> {}
+unsafe impl<T: Send> Send for IterMut<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
+unsafe impl<T: Sync> Sync for IterMut<'_, T> {}
 
 #[cfg(test)]
 mod tests {
diff --git a/src/liballoc/collections/mod.rs b/src/liballoc/collections/mod.rs
index 138f5d79bb008..5a33ddc14f004 100644
--- a/src/liballoc/collections/mod.rs
+++ b/src/liballoc/collections/mod.rs
@@ -23,25 +23,25 @@ pub mod btree_set {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
-pub use self::binary_heap::BinaryHeap;
+pub use binary_heap::BinaryHeap;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
-pub use self::btree_map::BTreeMap;
+pub use btree_map::BTreeMap;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
-pub use self::btree_set::BTreeSet;
+pub use btree_set::BTreeSet;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
-pub use self::linked_list::LinkedList;
+pub use linked_list::LinkedList;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(no_inline)]
-pub use self::vec_deque::VecDeque;
+pub use vec_deque::VecDeque;
 
-use alloc::{AllocErr, LayoutErr};
+use crate::alloc::{AllocErr, LayoutErr};
 
 /// Augments `AllocErr` with a CapacityOverflow variant.
 #[derive(Clone, PartialEq, Eq, Debug)]
diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs
index b3f7ef5fd6ecc..4e90f783ec6a5 100644
--- a/src/liballoc/collections/vec_deque.rs
+++ b/src/liballoc/collections/vec_deque.rs
@@ -7,22 +7,19 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::cmp::Ordering;
+use core::cmp::{self, Ordering};
 use core::fmt;
 use core::iter::{repeat_with, FromIterator, FusedIterator};
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
-use core::ops::{Index, IndexMut, RangeBounds};
-use core::ptr;
-use core::ptr::NonNull;
+use core::ops::{Index, IndexMut, RangeBounds, Try};
+use core::ptr::{self, NonNull};
 use core::slice;
-
 use core::hash::{Hash, Hasher};
-use core::cmp;
 
-use collections::CollectionAllocErr;
-use raw_vec::RawVec;
-use vec::Vec;
+use crate::collections::CollectionAllocErr;
+use crate::raw_vec::RawVec;
+use crate::vec::Vec;
 
 const INITIAL_CAPACITY: usize = 7; // 2^3 - 1
 const MINIMUM_CAPACITY: usize = 1; // 2 - 1
@@ -127,7 +124,7 @@ impl<T> VecDeque<T> {
         ptr::write(self.ptr().add(off), value);
     }
 
-    /// Returns `true` if and only if the buffer is at full capacity.
+    /// Returns `true` if the buffer is at full capacity.
     #[inline]
     fn is_full(&self) -> bool {
         self.cap() - self.len() == 1
@@ -563,7 +560,7 @@ impl<T> VecDeque<T> {
     /// Does nothing if the capacity is already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
-    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer `reserve` if future insertions are expected.
     ///
     /// # Errors
@@ -798,7 +795,7 @@ impl<T> VecDeque<T> {
     /// assert_eq!(&c[..], b);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<T> {
+    pub fn iter(&self) -> Iter<'_, T> {
         Iter {
             tail: self.tail,
             head: self.head,
@@ -824,7 +821,7 @@ impl<T> VecDeque<T> {
     /// assert_eq!(&buf.iter_mut().collect::<Vec<&mut i32>>()[..], b);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter_mut(&mut self) -> IterMut<T> {
+    pub fn iter_mut(&mut self) -> IterMut<'_, T> {
         IterMut {
             tail: self.tail,
             head: self.head,
@@ -927,7 +924,7 @@ impl<T> VecDeque<T> {
         self.tail == self.head
     }
 
-    /// Create a draining iterator that removes the specified range in the
+    /// Creates a draining iterator that removes the specified range in the
     /// `VecDeque` and yields the removed items.
     ///
     /// Note 1: The element range is removed even if the iterator is not
@@ -935,7 +932,7 @@ impl<T> VecDeque<T> {
     ///
     /// Note 2: It is unspecified how many elements are removed from the deque,
     /// if the `Drain` value is not dropped, but the borrow it holds expires
-    /// (eg. due to mem::forget).
+    /// (e.g., due to `mem::forget`).
     ///
     /// # Panics
     ///
@@ -958,7 +955,7 @@ impl<T> VecDeque<T> {
     /// ```
     #[inline]
     #[stable(feature = "drain", since = "1.6.0")]
-    pub fn drain<R>(&mut self, range: R) -> Drain<T>
+    pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>
         where R: RangeBounds<usize>
     {
         // Memory safety
@@ -1925,7 +1922,7 @@ impl<T> VecDeque<T> {
     ///
     /// # Panics
     ///
-    /// If `mid` is greater than `len()`.  Note that `mid == len()`
+    /// If `mid` is greater than `len()`. Note that `mid == len()`
     /// does _not_ panic and is a no-op rotation.
     ///
     /// # Complexity
@@ -1970,7 +1967,7 @@ impl<T> VecDeque<T> {
     ///
     /// # Panics
     ///
-    /// If `k` is greater than `len()`.  Note that `k == len()`
+    /// If `k` is greater than `len()`. Note that `k == len()`
     /// does _not_ panic and is a no-op rotation.
     ///
     /// # Complexity
@@ -2083,7 +2080,7 @@ trait RingSlices: Sized {
     }
 }
 
-impl<'a, T> RingSlices for &'a [T] {
+impl<T> RingSlices for &[T] {
     fn slice(self, from: usize, to: usize) -> Self {
         &self[from..to]
     }
@@ -2092,7 +2089,7 @@ impl<'a, T> RingSlices for &'a [T] {
     }
 }
 
-impl<'a, T> RingSlices for &'a mut [T] {
+impl<T> RingSlices for &mut [T] {
     fn slice(self, from: usize, to: usize) -> Self {
         &mut self[from..to]
     }
@@ -2123,8 +2120,8 @@ pub struct Iter<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let (front, back) = RingSlices::ring_slices(self.ring, self.head, self.tail);
         f.debug_tuple("Iter")
             .field(&front)
@@ -2135,8 +2132,8 @@ impl<'a, T: 'a + fmt::Debug> fmt::Debug for Iter<'a, T> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter {
             ring: self.ring,
             tail: self.tail,
@@ -2172,6 +2169,31 @@ impl<'a, T> Iterator for Iter<'a, T> {
         accum = front.iter().fold(accum, &mut f);
         back.iter().fold(accum, &mut f)
     }
+
+    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> R,
+        R: Try<Ok = B>,
+    {
+        let (mut iter, final_res);
+        if self.tail <= self.head {
+            // single slice self.ring[self.tail..self.head]
+            iter = self.ring[self.tail..self.head].iter();
+            final_res = iter.try_fold(init, &mut f);
+        } else {
+            // two slices: self.ring[self.tail..], self.ring[..self.head]
+            let (front, back) = self.ring.split_at(self.tail);
+            let mut back_iter = back.iter();
+            let res = back_iter.try_fold(init, &mut f);
+            let len = self.ring.len();
+            self.tail = (self.ring.len() - back_iter.len()) & (len - 1);
+            iter = front[..self.head].iter();
+            final_res = iter.try_fold(res?, &mut f);
+        }
+        self.tail = self.head - iter.len();
+        final_res
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -2192,17 +2214,41 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
         accum = back.iter().rfold(accum, &mut f);
         front.iter().rfold(accum, &mut f)
     }
+
+    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> R,
+        R: Try<Ok = B>,
+    {
+        let (mut iter, final_res);
+        if self.tail <= self.head {
+            // single slice self.ring[self.tail..self.head]
+            iter = self.ring[self.tail..self.head].iter();
+            final_res = iter.try_rfold(init, &mut f);
+        } else {
+            // two slices: self.ring[self.tail..], self.ring[..self.head]
+            let (front, back) = self.ring.split_at(self.tail);
+            let mut front_iter = front[..self.head].iter();
+            let res = front_iter.try_rfold(init, &mut f);
+            self.head = front_iter.len();
+            iter = back.iter();
+            final_res = iter.try_rfold(res?, &mut f);
+        }
+        self.head = self.tail + iter.len();
+        final_res
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for Iter<'a, T> {
+impl<T> ExactSizeIterator for Iter<'_, T> {
     fn is_empty(&self) -> bool {
         self.head == self.tail
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Iter<'a, T> {}
+impl<T> FusedIterator for Iter<'_, T> {}
 
 
 /// A mutable iterator over the elements of a `VecDeque`.
@@ -2220,8 +2266,8 @@ pub struct IterMut<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for IterMut<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for IterMut<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let (front, back) = RingSlices::ring_slices(&*self.ring, self.head, self.tail);
         f.debug_tuple("IterMut")
             .field(&front)
@@ -2288,14 +2334,14 @@ impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> ExactSizeIterator for IterMut<'a, T> {
+impl<T> ExactSizeIterator for IterMut<'_, T> {
     fn is_empty(&self) -> bool {
         self.head == self.tail
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for IterMut<'a, T> {}
+impl<T> FusedIterator for IterMut<'_, T> {}
 
 /// An owning iterator over the elements of a `VecDeque`.
 ///
@@ -2312,7 +2358,7 @@ pub struct IntoIter<T> {
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("IntoIter")
          .field(&self.inner)
          .finish()
@@ -2369,8 +2415,8 @@ pub struct Drain<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Drain<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Drain")
          .field(&self.after_tail)
          .field(&self.after_head)
@@ -2380,12 +2426,12 @@ impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a, T: Sync> Sync for Drain<'a, T> {}
+unsafe impl<T: Sync> Sync for Drain<'_, T> {}
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a, T: Send> Send for Drain<'a, T> {}
+unsafe impl<T: Send> Send for Drain<'_, T> {}
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> Drop for Drain<'a, T> {
+impl<T> Drop for Drain<'_, T> {
     fn drop(&mut self) {
         self.for_each(drop);
 
@@ -2432,7 +2478,7 @@ impl<'a, T: 'a> Drop for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> Iterator for Drain<'a, T> {
+impl<T> Iterator for Drain<'_, T> {
     type Item = T;
 
     #[inline]
@@ -2447,7 +2493,7 @@ impl<'a, T: 'a> Iterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
+impl<T> DoubleEndedIterator for Drain<'_, T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> {
         self.iter.next_back().map(|elt| unsafe { ptr::read(elt) })
@@ -2455,10 +2501,10 @@ impl<'a, T: 'a> DoubleEndedIterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T: 'a> ExactSizeIterator for Drain<'a, T> {}
+impl<T> ExactSizeIterator for Drain<'_, T> {}
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T: 'a> FusedIterator for Drain<'a, T> {}
+impl<T> FusedIterator for Drain<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<A: PartialEq> PartialEq for VecDeque<A> {
@@ -2508,7 +2554,7 @@ macro_rules! __impl_slice_eq1 {
     };
     ($Lhs: ty, $Rhs: ty, $Bound: ident) => {
         #[stable(feature = "vec_deque_partial_eq_slice", since = "1.17.0")]
-        impl<'a, 'b, A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
+        impl<A: $Bound, B> PartialEq<$Rhs> for $Lhs where A: PartialEq<B> {
             fn eq(&self, other: &$Rhs) -> bool {
                 if self.len() != other.len() {
                     return false;
@@ -2522,15 +2568,15 @@ macro_rules! __impl_slice_eq1 {
 }
 
 __impl_slice_eq1! { VecDeque<A>, Vec<B> }
-__impl_slice_eq1! { VecDeque<A>, &'b [B] }
-__impl_slice_eq1! { VecDeque<A>, &'b mut [B] }
+__impl_slice_eq1! { VecDeque<A>, &[B] }
+__impl_slice_eq1! { VecDeque<A>, &mut [B] }
 
 macro_rules! array_impls {
     ($($N: expr)+) => {
         $(
             __impl_slice_eq1! { VecDeque<A>, [B; $N] }
-            __impl_slice_eq1! { VecDeque<A>, &'b [B; $N] }
-            __impl_slice_eq1! { VecDeque<A>, &'b mut [B; $N] }
+            __impl_slice_eq1! { VecDeque<A>, &[B; $N] }
+            __impl_slice_eq1! { VecDeque<A>, &mut [B; $N] }
         )+
     }
 }
@@ -2646,7 +2692,7 @@ impl<'a, T: 'a + Copy> Extend<&'a T> for VecDeque<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Debug> fmt::Debug for VecDeque<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_list().entries(self).finish()
     }
 }
@@ -2750,7 +2796,7 @@ impl<T> From<VecDeque<T>> for Vec<T> {
 
 #[cfg(test)]
 mod tests {
-    use test;
+    use ::test;
 
     use super::VecDeque;
 
@@ -3028,7 +3074,7 @@ mod tests {
 
     #[test]
     fn test_from_vec() {
-        use vec::Vec;
+        use crate::vec::Vec;
         for cap in 0..35 {
             for len in 0..=cap {
                 let mut vec = Vec::with_capacity(cap);
@@ -3044,7 +3090,7 @@ mod tests {
 
     #[test]
     fn test_vec_from_vecdeque() {
-        use vec::Vec;
+        use crate::vec::Vec;
 
         fn create_vec_and_test_convert(cap: usize, offset: usize, len: usize) {
             let mut vd = VecDeque::with_capacity(cap);
@@ -3106,7 +3152,7 @@ mod tests {
 
     #[test]
     fn issue_53529() {
-        use boxed::Box;
+        use crate::boxed::Box;
 
         let mut dst = VecDeque::new();
         dst.push_front(Box::new(1));
diff --git a/src/liballoc/fmt.rs b/src/liballoc/fmt.rs
index a1e7533449c69..d2ba9b001916c 100644
--- a/src/liballoc/fmt.rs
+++ b/src/liballoc/fmt.rs
@@ -27,7 +27,7 @@
 //! will then parse the format string and determine if the list of arguments
 //! provided is suitable to pass to this format string.
 //!
-//! To convert a single value to a string, use the [`to_string`] method.  This
+//! To convert a single value to a string, use the [`to_string`] method. This
 //! will use the [`Display`] formatting trait.
 //!
 //! ## Positional parameters
@@ -102,7 +102,7 @@
 //! When requesting that an argument be formatted with a particular type, you
 //! are actually requesting that an argument ascribes to a particular trait.
 //! This allows multiple actual types to be formatted via `{:x}` (like [`i8`] as
-//! well as [`isize`]).  The current mapping of types to traits is:
+//! well as [`isize`]). The current mapping of types to traits is:
 //!
 //! * *nothing* ⇒ [`Display`]
 //! * `?` ⇒ [`Debug`]
@@ -427,7 +427,7 @@
 //! 3. An asterisk `.*`:
 //!
 //!    `.*` means that this `{...}` is associated with *two* format inputs rather than one: the
-//!    first input holds the `usize` precision, and the second holds the value to print.  Note that
+//!    first input holds the `usize` precision, and the second holds the value to print. Note that
 //!    in this case, if one uses the format string `{<arg>:<spec>.*}`, then the `<arg>` part refers
 //!    to the *value* to print, and the `precision` must come in the input preceding `<arg>`.
 //!
@@ -527,7 +527,7 @@ pub use core::fmt::{DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple};
 #[stable(feature = "fmt_flags_align", since = "1.28.0")]
 pub use core::fmt::{Alignment};
 
-use string;
+use crate::string;
 
 /// The `format` function takes an [`Arguments`] struct and returns the resulting
 /// formatted string.
@@ -557,7 +557,7 @@ use string;
 /// [`format_args!`]: ../../std/macro.format_args.html
 /// [`format!`]: ../../std/macro.format.html
 #[stable(feature = "rust1", since = "1.0.0")]
-pub fn format(args: Arguments) -> string::String {
+pub fn format(args: Arguments<'_>) -> string::String {
     let capacity = args.estimated_capacity();
     let mut output = string::String::with_capacity(capacity);
     output
diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index 3050a93ef39a0..440ce8ac5e842 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -55,18 +55,19 @@
             reason = "this library is unlikely to be stabilized in its current \
                       form or name",
             issue = "27783")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 #![no_std]
 #![needs_allocator]
 
-#![deny(intra_doc_link_resolution_failure)]
-#![deny(missing_debug_implementations)]
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
+
+#![warn(deprecated_in_future)]
+#![warn(intra_doc_link_resolution_failure)]
+#![warn(missing_debug_implementations)]
 
-#![cfg_attr(not(test), feature(fn_traits))]
 #![cfg_attr(not(test), feature(generator_trait))]
 #![cfg_attr(test, feature(test))]
 
@@ -84,6 +85,7 @@
 #![feature(dropck_eyepatch)]
 #![feature(exact_size_is_empty)]
 #![feature(fmt_internals)]
+#![feature(fn_traits)]
 #![feature(fundamental)]
 #![feature(futures_api)]
 #![feature(lang_items)]
@@ -97,8 +99,8 @@
 #![feature(rustc_attrs)]
 #![feature(receiver_trait)]
 #![feature(specialization)]
-#![feature(split_ascii_whitespace)]
 #![feature(staged_api)]
+#![feature(std_internals)]
 #![feature(str_internals)]
 #![feature(trusted_len)]
 #![feature(try_reserve)]
@@ -110,8 +112,9 @@
 #![feature(rustc_const_unstable)]
 #![feature(const_vec_new)]
 #![feature(slice_partition_dedup)]
-#![feature(maybe_uninit)]
+#![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)]
 #![feature(alloc_layout_extra)]
+#![feature(try_trait)]
 
 // Allow testing this library
 
@@ -120,8 +123,6 @@
 extern crate std;
 #[cfg(test)]
 extern crate test;
-#[cfg(test)]
-extern crate rand;
 
 // Module with internal macros used by other modules (needs to be included before other modules).
 #[macro_use]
@@ -131,10 +132,6 @@ mod macros;
 
 pub mod alloc;
 
-#[unstable(feature = "futures_api",
-           reason = "futures in libcore are unstable",
-           issue = "50547")]
-pub mod task;
 // Primitive types using the heaps above
 
 // Need to conditionally define the mod from `boxed.rs` to avoid
@@ -163,5 +160,5 @@ pub mod vec;
 
 #[cfg(not(test))]
 mod std {
-    pub use core::ops;      // RangeFull
+    pub use core::ops; // RangeFull
 }
diff --git a/src/liballoc/macros.rs b/src/liballoc/macros.rs
index db91b07fa71b4..eb3410078513d 100644
--- a/src/liballoc/macros.rs
+++ b/src/liballoc/macros.rs
@@ -34,7 +34,8 @@
 #[cfg(not(test))]
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(not(stage0), allow_internal_unstable(box_syntax))]
+#[cfg_attr(stage0, allow_internal_unstable)]
 macro_rules! vec {
     ($elem:expr; $n:expr) => (
         $crate::vec::from_elem($elem, $n)
@@ -62,18 +63,18 @@ macro_rules! vec {
 
 /// Creates a `String` using interpolation of runtime expressions.
 ///
-/// The first argument `format!` receives is a format string.  This must be a string
-/// literal.  The power of the formatting string is in the `{}`s contained.
+/// The first argument `format!` receives is a format string. This must be a string
+/// literal. The power of the formatting string is in the `{}`s contained.
 ///
 /// Additional parameters passed to `format!` replace the `{}`s within the
 /// formatting string in the order given unless named or positional parameters
-/// are used, see [`std::fmt`][fmt] for more information.
+/// are used; see [`std::fmt`][fmt] for more information.
 ///
 /// A common use for `format!` is concatenation and interpolation of strings.
 /// The same convention is used with [`print!`] and [`write!`] macros,
 /// depending on the intended destination of the string.
 ///
-/// To convert a single value to a string, use the [`to_string`] method.  This
+/// To convert a single value to a string, use the [`to_string`] method. This
 /// will use the [`Display`] formatting trait.
 ///
 /// [fmt]: ../std/fmt/index.html
diff --git a/src/liballoc/prelude.rs b/src/liballoc/prelude.rs
index 7cd22095de417..6767cf89f73ba 100644
--- a/src/liballoc/prelude.rs
+++ b/src/liballoc/prelude.rs
@@ -12,8 +12,8 @@
 
 #![unstable(feature = "alloc", issue = "27783")]
 
-#[unstable(feature = "alloc", issue = "27783")] pub use borrow::ToOwned;
-#[unstable(feature = "alloc", issue = "27783")] pub use boxed::Box;
-#[unstable(feature = "alloc", issue = "27783")] pub use slice::SliceConcatExt;
-#[unstable(feature = "alloc", issue = "27783")] pub use string::{String, ToString};
-#[unstable(feature = "alloc", issue = "27783")] pub use vec::Vec;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::borrow::ToOwned;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::boxed::Box;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::slice::SliceConcatExt;
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::string::{String, ToString};
+#[unstable(feature = "alloc", issue = "27783")] pub use crate::vec::Vec;
diff --git a/src/liballoc/raw_vec.rs b/src/liballoc/raw_vec.rs
index 5e4aac9ce7871..fe28fe5095cce 100644
--- a/src/liballoc/raw_vec.rs
+++ b/src/liballoc/raw_vec.rs
@@ -7,10 +7,9 @@ use core::ops::Drop;
 use core::ptr::{self, NonNull, Unique};
 use core::slice;
 
-use alloc::{Alloc, Layout, Global, handle_alloc_error};
-use collections::CollectionAllocErr;
-use collections::CollectionAllocErr::*;
-use boxed::Box;
+use crate::alloc::{Alloc, Layout, Global, handle_alloc_error};
+use crate::collections::CollectionAllocErr::{self, *};
+use crate::boxed::Box;
 
 /// A low-level utility for more ergonomically allocating, reallocating, and deallocating
 /// a buffer of memory on the heap without having to worry about all the corner cases
@@ -336,7 +335,7 @@ impl<T, A: Alloc> RawVec<T, A> {
     /// enough to want to do that it's easiest to just have a dedicated method. Slightly
     /// more efficient logic can be provided for this than the general case.
     ///
-    /// Returns true if the reallocation attempt has succeeded, or false otherwise.
+    /// Returns `true` if the reallocation attempt has succeeded.
     ///
     /// # Panics
     ///
@@ -505,7 +504,7 @@ impl<T, A: Alloc> RawVec<T, A> {
     /// the requested space. This is not really unsafe, but the unsafe
     /// code *you* write that relies on the behavior of this function may break.
     ///
-    /// Returns true if the reallocation attempt has succeeded, or false otherwise.
+    /// Returns `true` if the reallocation attempt has succeeded.
     ///
     /// # Panics
     ///
@@ -621,14 +620,14 @@ enum Fallibility {
     Infallible,
 }
 
-use self::Fallibility::*;
+use Fallibility::*;
 
 enum ReserveStrategy {
     Exact,
     Amortized,
 }
 
-use self::ReserveStrategy::*;
+use ReserveStrategy::*;
 
 impl<T, A: Alloc> RawVec<T, A> {
     fn reserve_internal(
@@ -639,7 +638,7 @@ impl<T, A: Alloc> RawVec<T, A> {
         strategy: ReserveStrategy,
     ) -> Result<(), CollectionAllocErr> {
         unsafe {
-            use alloc::AllocErr;
+            use crate::alloc::AllocErr;
 
             // NOTE: we don't early branch on ZSTs here because we want this
             // to actually catch "asking for more than usize::MAX" in that case.
@@ -733,7 +732,7 @@ unsafe impl<#[may_dangle] T, A: Alloc> Drop for RawVec<T, A> {
 
 #[inline]
 fn alloc_guard(alloc_size: usize) -> Result<(), CollectionAllocErr> {
-    if mem::size_of::<usize>() < 8 && alloc_size > ::core::isize::MAX as usize {
+    if mem::size_of::<usize>() < 8 && alloc_size > core::isize::MAX as usize {
         Err(CapacityOverflow)
     } else {
         Ok(())
@@ -753,7 +752,7 @@ mod tests {
 
     #[test]
     fn allocator_param() {
-        use alloc::AllocErr;
+        use crate::alloc::AllocErr;
 
         // Writing a test of integration between third-party
         // allocators and RawVec is a little tricky because the RawVec
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index d3a55c59ff69c..12f75d84211e6 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -1,5 +1,3 @@
-#![allow(deprecated)]
-
 //! Single-threaded reference-counting pointers. 'Rc' stands for 'Reference
 //! Counted'.
 //!
@@ -229,7 +227,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 #[cfg(not(test))]
-use boxed::Box;
+use crate::boxed::Box;
 #[cfg(test)]
 use std::boxed::Box;
 
@@ -240,19 +238,18 @@ use core::cmp::Ordering;
 use core::fmt;
 use core::hash::{Hash, Hasher};
 use core::intrinsics::abort;
-use core::marker;
-use core::marker::{Unpin, Unsize, PhantomData};
+use core::marker::{self, Unpin, Unsize, PhantomData};
 use core::mem::{self, align_of_val, forget, size_of_val};
-use core::ops::{Deref, Receiver};
-use core::ops::{CoerceUnsized, DispatchFromDyn};
+use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn};
 use core::pin::Pin;
 use core::ptr::{self, NonNull};
+use core::slice::from_raw_parts_mut;
 use core::convert::From;
 use core::usize;
 
-use alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
-use string::String;
-use vec::Vec;
+use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
+use crate::string::String;
+use crate::vec::Vec;
 
 struct RcBox<T: ?Sized> {
     strong: Cell<usize>,
@@ -435,6 +432,27 @@ impl<T: ?Sized> Rc<T> {
         }
     }
 
+    /// Consumes the `Rc`, returning the wrapped pointer as `NonNull<T>`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(rc_into_raw_non_null)]
+    ///
+    /// use std::rc::Rc;
+    ///
+    /// let x = Rc::new(10);
+    /// let ptr = Rc::into_raw_non_null(x);
+    /// let deref = unsafe { *ptr.as_ref() };
+    /// assert_eq!(deref, 10);
+    /// ```
+    #[unstable(feature = "rc_into_raw_non_null", issue = "47336")]
+    #[inline]
+    pub fn into_raw_non_null(this: Self) -> NonNull<T> {
+        // safe because Rc guarantees its pointer is non-null
+        unsafe { NonNull::new_unchecked(Rc::into_raw(this) as *mut _) }
+    }
+
     /// Creates a new [`Weak`][weak] pointer to this value.
     ///
     /// [weak]: struct.Weak.html
@@ -494,7 +512,7 @@ impl<T: ?Sized> Rc<T> {
         this.strong()
     }
 
-    /// Returns true if there are no other `Rc` or [`Weak`][weak] pointers to
+    /// Returns `true` if there are no other `Rc` or [`Weak`][weak] pointers to
     /// this inner value.
     ///
     /// [weak]: struct.Weak.html
@@ -543,7 +561,7 @@ impl<T: ?Sized> Rc<T> {
 
     #[inline]
     #[stable(feature = "ptr_eq", since = "1.17.0")]
-    /// Returns true if the two `Rc`s point to the same value (not
+    /// Returns `true` if the two `Rc`s point to the same value (not
     /// just values that compare as equal).
     ///
     /// # Examples
@@ -747,8 +765,6 @@ impl<T: Clone> RcFromSlice<T> for Rc<[T]> {
 
         impl<T> Drop for Guard<T> {
             fn drop(&mut self) {
-                use core::slice::from_raw_parts_mut;
-
                 unsafe {
                     let slice = from_raw_parts_mut(self.elems, self.n_elems);
                     ptr::drop_in_place(slice);
@@ -1102,21 +1118,21 @@ impl<T: ?Sized + Hash> Hash for Rc<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Display> fmt::Display for Rc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for Rc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> fmt::Pointer for Rc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Pointer::fmt(&(&**self as *const T), f)
     }
 }
@@ -1286,8 +1302,40 @@ impl<T: ?Sized> Weak<T> {
         }
     }
 
-    /// Return `None` when the pointer is dangling and there is no allocated `RcBox`,
-    /// i.e., this `Weak` was created by `Weak::new`
+    /// Gets the number of strong (`Rc`) pointers pointing to this value.
+    ///
+    /// If `self` was created using [`Weak::new`], this will return 0.
+    ///
+    /// [`Weak::new`]: #method.new
+    #[unstable(feature = "weak_counts", issue = "57977")]
+    pub fn strong_count(&self) -> usize {
+        if let Some(inner) = self.inner() {
+            inner.strong()
+        } else {
+            0
+        }
+    }
+
+    /// Gets the number of `Weak` pointers pointing to this value.
+    ///
+    /// If `self` was created using [`Weak::new`], this will return `None`. If
+    /// not, the returned value is at least 1, since `self` still points to the
+    /// value.
+    ///
+    /// [`Weak::new`]: #method.new
+    #[unstable(feature = "weak_counts", issue = "57977")]
+    pub fn weak_count(&self) -> Option<usize> {
+        self.inner().map(|inner| {
+            if inner.strong() > 0 {
+                inner.weak() - 1  // subtract the implicit weak ptr
+            } else {
+                inner.weak()
+            }
+        })
+    }
+
+    /// Returns `None` when the pointer is dangling and there is no allocated `RcBox`
+    /// (i.e., when this `Weak` was created by `Weak::new`).
     #[inline]
     fn inner(&self) -> Option<&RcBox<T>> {
         if is_dangling(self.ptr) {
@@ -1297,7 +1345,7 @@ impl<T: ?Sized> Weak<T> {
         }
     }
 
-    /// Returns true if the two `Weak`s point to the same value (not just values
+    /// Returns `true` if the two `Weak`s point to the same value (not just values
     /// that compare as equal).
     ///
     /// # Notes
@@ -1408,7 +1456,7 @@ impl<T: ?Sized> Clone for Weak<T> {
 
 #[stable(feature = "rc_weak", since = "1.4.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for Weak<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "(Weak)")
     }
 }
@@ -1513,8 +1561,7 @@ mod tests {
     use super::{Rc, Weak};
     use std::boxed::Box;
     use std::cell::RefCell;
-    use std::option::Option;
-    use std::option::Option::{None, Some};
+    use std::option::Option::{self, None, Some};
     use std::result::Result::{Err, Ok};
     use std::mem::drop;
     use std::clone::Clone;
@@ -1624,6 +1671,33 @@ mod tests {
         drop(c);
     }
 
+    #[test]
+    fn weak_counts() {
+        assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None);
+        assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0);
+
+        let a = Rc::new(0);
+        let w = Rc::downgrade(&a);
+        assert_eq!(Weak::strong_count(&w), 1);
+        assert_eq!(Weak::weak_count(&w), Some(1));
+        let w2 = w.clone();
+        assert_eq!(Weak::strong_count(&w), 1);
+        assert_eq!(Weak::weak_count(&w), Some(2));
+        assert_eq!(Weak::strong_count(&w2), 1);
+        assert_eq!(Weak::weak_count(&w2), Some(2));
+        drop(w);
+        assert_eq!(Weak::strong_count(&w2), 1);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        let a2 = a.clone();
+        assert_eq!(Weak::strong_count(&w2), 2);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        drop(a2);
+        drop(a);
+        assert_eq!(Weak::strong_count(&w2), 0);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        drop(w2);
+    }
+
     #[test]
     fn try_unwrap() {
         let x = Rc::new(3);
diff --git a/src/liballoc/slice.rs b/src/liballoc/slice.rs
index db19f778617f4..f4b2d463778a9 100644
--- a/src/liballoc/slice.rs
+++ b/src/liballoc/slice.rs
@@ -87,15 +87,15 @@
 // It's cleaner to just turn off the unused_imports warning than to fix them.
 #![cfg_attr(test, allow(unused_imports, dead_code))]
 
+use core::borrow::{Borrow, BorrowMut};
 use core::cmp::Ordering::{self, Less};
-use core::mem::size_of;
-use core::mem;
+use core::mem::{self, size_of};
 use core::ptr;
 use core::{u8, u16, u32};
 
-use borrow::{Borrow, BorrowMut, ToOwned};
-use boxed::Box;
-use vec::Vec;
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::vec::Vec;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::slice::{Chunks, Windows};
@@ -125,24 +125,24 @@ pub use core::slice::{RChunks, RChunksMut, RChunksExact, RChunksExactMut};
 // HACK(japaric) needed for the implementation of `vec!` macro during testing
 // NB see the hack module in this file for more details
 #[cfg(test)]
-pub use self::hack::into_vec;
+pub use hack::into_vec;
 
 // HACK(japaric) needed for the implementation of `Vec::clone` during testing
 // NB see the hack module in this file for more details
 #[cfg(test)]
-pub use self::hack::to_vec;
+pub use hack::to_vec;
 
 // HACK(japaric): With cfg(test) `impl [T]` is not available, these three
 // functions are actually methods that are in `impl [T]` but not in
 // `core::slice::SliceExt` - we need to supply these functions for the
 // `test_permutations` test
 mod hack {
-    use boxed::Box;
     use core::mem;
 
+    use crate::boxed::Box;
+    use crate::vec::Vec;
     #[cfg(test)]
-    use string::ToString;
-    use vec::Vec;
+    use crate::string::ToString;
 
     pub fn into_vec<T>(mut b: Box<[T]>) -> Vec<T> {
         unsafe {
@@ -205,10 +205,10 @@ impl<T> [T] {
     ///
     /// The comparator function must define a total ordering for the elements in the slice. If
     /// the ordering is not total, the order of the elements is unspecified. An order is a
-    /// total order if it is (for all a, b and c):
+    /// total order if it is (for all `a`, `b` and `c`):
     ///
-    /// * total and antisymmetric: exactly one of a < b, a == b or a > b is true; and
-    /// * transitive, a < b and b < c implies a < c. The same must hold for both == and >.
+    /// * total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
+    /// * transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
     ///
     /// For example, while [`f64`] doesn't implement [`Ord`] because `NaN != NaN`, we can use
     /// `partial_cmp` as our sort function when we know the slice doesn't contain a `NaN`.
@@ -257,6 +257,10 @@ impl<T> [T] {
     /// This sort is stable (i.e., does not reorder equal elements) and `O(m n log(m n))`
     /// worst-case, where the key function is `O(m)`.
     ///
+    /// For expensive key functions (e.g. functions that are not simple property accesses or
+    /// basic operations), [`sort_by_cached_key`](#method.sort_by_cached_key) is likely to be
+    /// significantly faster, as it does not recompute element keys.
+    ///
     /// When applicable, unstable sorting is preferred because it is generally faster than stable
     /// sorting and it doesn't allocate auxiliary memory.
     /// See [`sort_unstable_by_key`](#method.sort_unstable_by_key).
@@ -312,7 +316,6 @@ impl<T> [T] {
     /// # Examples
     ///
     /// ```
-    /// #![feature(slice_sort_by_cached_key)]
     /// let mut v = [-5i32, 4, 32, -3, 2];
     ///
     /// v.sort_by_cached_key(|k| k.to_string());
@@ -320,7 +323,7 @@ impl<T> [T] {
     /// ```
     ///
     /// [pdqsort]: https://github.com/orlp/pdqsort
-    #[unstable(feature = "slice_sort_by_cached_key", issue = "34447")]
+    #[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")]
     #[inline]
     pub fn sort_by_cached_key<K, F>(&mut self, f: F)
         where F: FnMut(&T) -> K, K: Ord
diff --git a/src/liballoc/str.rs b/src/liballoc/str.rs
index 60d9f1626138e..a36804bddff32 100644
--- a/src/liballoc/str.rs
+++ b/src/liballoc/str.rs
@@ -28,20 +28,18 @@
 // It's cleaner to just turn off the unused_imports warning than to fix them.
 #![allow(unused_imports)]
 
-use core::fmt;
-use core::str as core_str;
-use core::str::pattern::Pattern;
-use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
+use core::borrow::Borrow;
+use core::str::pattern::{Pattern, Searcher, ReverseSearcher, DoubleEndedSearcher};
 use core::mem;
 use core::ptr;
 use core::iter::FusedIterator;
 use core::unicode::conversions;
 
-use borrow::{Borrow, ToOwned};
-use boxed::Box;
-use slice::{SliceConcatExt, SliceIndex};
-use string::String;
-use vec::Vec;
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::slice::{SliceConcatExt, SliceIndex};
+use crate::string::String;
+use crate::vec::Vec;
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::str::{FromStr, Utf8Error};
@@ -68,7 +66,7 @@ pub use core::str::SplitWhitespace;
 pub use core::str::pattern;
 #[stable(feature = "encode_utf16", since = "1.8.0")]
 pub use core::str::EncodeUtf16;
-#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
 pub use core::str::SplitAsciiWhitespace;
 
 #[unstable(feature = "slice_concat_ext",
@@ -443,45 +441,6 @@ impl str {
         return s;
     }
 
-    /// Escapes each char in `s` with [`char::escape_debug`].
-    ///
-    /// Note: only extended grapheme codepoints that begin the string will be
-    /// escaped.
-    ///
-    /// [`char::escape_debug`]: primitive.char.html#method.escape_debug
-    #[unstable(feature = "str_escape",
-               reason = "return type may change to be an iterator",
-               issue = "27791")]
-    pub fn escape_debug(&self) -> String {
-        let mut string = String::with_capacity(self.len());
-        let mut chars = self.chars();
-        if let Some(first) = chars.next() {
-            string.extend(first.escape_debug_ext(true))
-        }
-        string.extend(chars.flat_map(|c| c.escape_debug_ext(false)));
-        string
-    }
-
-    /// Escapes each char in `s` with [`char::escape_default`].
-    ///
-    /// [`char::escape_default`]: primitive.char.html#method.escape_default
-    #[unstable(feature = "str_escape",
-               reason = "return type may change to be an iterator",
-               issue = "27791")]
-    pub fn escape_default(&self) -> String {
-        self.chars().flat_map(|c| c.escape_default()).collect()
-    }
-
-    /// Escapes each char in `s` with [`char::escape_unicode`].
-    ///
-    /// [`char::escape_unicode`]: primitive.char.html#method.escape_unicode
-    #[unstable(feature = "str_escape",
-               reason = "return type may change to be an iterator",
-               issue = "27791")]
-    pub fn escape_unicode(&self) -> String {
-        self.chars().flat_map(|c| c.escape_unicode()).collect()
-    }
-
     /// Converts a [`Box<str>`] into a [`String`] without copying or allocating.
     ///
     /// [`String`]: string/struct.String.html
@@ -612,3 +571,4 @@ impl str {
 pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> {
     Box::from_raw(Box::into_raw(v) as *mut str)
 }
+
diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index fa15e9ad9018e..84c35c6f1bd2b 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -50,17 +50,16 @@ use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
 use core::fmt;
 use core::hash;
 use core::iter::{FromIterator, FusedIterator};
-use core::ops::Bound::{Excluded, Included, Unbounded};
 use core::ops::{self, Add, AddAssign, Index, IndexMut, RangeBounds};
+use core::ops::Bound::{Excluded, Included, Unbounded};
 use core::ptr;
-use core::str::pattern::Pattern;
-use core::str::lossy;
+use core::str::{pattern::Pattern, lossy};
 
-use collections::CollectionAllocErr;
-use borrow::{Cow, ToOwned};
-use boxed::Box;
-use str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars};
-use vec::Vec;
+use crate::borrow::{Cow, ToOwned};
+use crate::collections::CollectionAllocErr;
+use crate::boxed::Box;
+use crate::str::{self, from_boxed_utf8_unchecked, FromStr, Utf8Error, Chars};
+use crate::vec::Vec;
 
 /// A UTF-8 encoded, growable string.
 ///
@@ -964,7 +963,7 @@ impl String {
     /// Does nothing if the capacity is already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
-    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer `reserve` if future insertions are expected.
     ///
     /// # Errors
@@ -1378,9 +1377,7 @@ impl String {
         self.vec.len()
     }
 
-    /// Returns `true` if this `String` has a length of zero.
-    ///
-    /// Returns `false` otherwise.
+    /// Returns `true` if this `String` has a length of zero, and `false` otherwise.
     ///
     /// # Examples
     ///
@@ -1485,7 +1482,7 @@ impl String {
     /// assert_eq!(s, "");
     /// ```
     #[stable(feature = "drain", since = "1.6.0")]
-    pub fn drain<R>(&mut self, range: R) -> Drain
+    pub fn drain<R>(&mut self, range: R) -> Drain<'_>
         where R: RangeBounds<usize>
     {
         // Memory safety
@@ -1669,14 +1666,14 @@ impl FromUtf8Error {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for FromUtf8Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&self.error, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for FromUtf16Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt("invalid utf-16: lone surrogate found", f)
     }
 }
@@ -1867,7 +1864,7 @@ impl Default for String {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for String {
     #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&**self, f)
     }
 }
@@ -1875,7 +1872,7 @@ impl fmt::Display for String {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Debug for String {
     #[inline]
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }
@@ -1926,7 +1923,7 @@ impl hash::Hash for String {
 /// let c = a.to_string() + b;
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Add<&'a str> for String {
+impl Add<&str> for String {
     type Output = String;
 
     #[inline]
@@ -1940,7 +1937,7 @@ impl<'a> Add<&'a str> for String {
 ///
 /// This has the same behavior as the [`push_str`][String::push_str] method.
 #[stable(feature = "stringaddassign", since = "1.12.0")]
-impl<'a> AddAssign<&'a str> for String {
+impl AddAssign<&str> for String {
     #[inline]
     fn add_assign(&mut self, other: &str) {
         self.push_str(other);
@@ -2097,14 +2094,14 @@ impl Clone for ParseError {
 
 #[stable(feature = "str_parse_error", since = "1.5.0")]
 impl fmt::Debug for ParseError {
-    fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {}
     }
 }
 
 #[stable(feature = "str_parse_error2", since = "1.8.0")]
 impl fmt::Display for ParseError {
-    fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {}
     }
 }
@@ -2156,7 +2153,7 @@ pub trait ToString {
 impl<T: fmt::Display + ?Sized> ToString for T {
     #[inline]
     default fn to_string(&self) -> String {
-        use core::fmt::Write;
+        use fmt::Write;
         let mut buf = String::new();
         buf.write_fmt(format_args!("{}", self))
            .expect("a Display implementation returned an error unexpectedly");
@@ -2174,7 +2171,7 @@ impl ToString for str {
 }
 
 #[stable(feature = "cow_str_to_string_specialization", since = "1.17.0")]
-impl<'a> ToString for Cow<'a, str> {
+impl ToString for Cow<'_, str> {
     #[inline]
     fn to_string(&self) -> String {
         self[..].to_owned()
@@ -2364,19 +2361,19 @@ pub struct Drain<'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a> fmt::Debug for Drain<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl fmt::Debug for Drain<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad("Drain { .. }")
     }
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a> Sync for Drain<'a> {}
+unsafe impl Sync for Drain<'_> {}
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a> Send for Drain<'a> {}
+unsafe impl Send for Drain<'_> {}
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a> Drop for Drain<'a> {
+impl Drop for Drain<'_> {
     fn drop(&mut self) {
         unsafe {
             // Use Vec::drain. "Reaffirm" the bounds checks to avoid
@@ -2390,7 +2387,7 @@ impl<'a> Drop for Drain<'a> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a> Iterator for Drain<'a> {
+impl Iterator for Drain<'_> {
     type Item = char;
 
     #[inline]
@@ -2404,7 +2401,7 @@ impl<'a> Iterator for Drain<'a> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a> DoubleEndedIterator for Drain<'a> {
+impl DoubleEndedIterator for Drain<'_> {
     #[inline]
     fn next_back(&mut self) -> Option<char> {
         self.iter.next_back()
@@ -2412,4 +2409,4 @@ impl<'a> DoubleEndedIterator for Drain<'a> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a> FusedIterator for Drain<'a> {}
+impl FusedIterator for Drain<'_> {}
diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 390a079165054..b7d7995b540ba 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -11,23 +11,23 @@ use core::sync::atomic;
 use core::sync::atomic::Ordering::{Acquire, Relaxed, Release, SeqCst};
 use core::borrow;
 use core::fmt;
-use core::cmp::Ordering;
+use core::cmp::{self, Ordering};
 use core::intrinsics::abort;
 use core::mem::{self, align_of_val, size_of_val};
-use core::ops::{Deref, Receiver};
-use core::ops::{CoerceUnsized, DispatchFromDyn};
+use core::ops::{Deref, Receiver, CoerceUnsized, DispatchFromDyn};
 use core::pin::Pin;
 use core::ptr::{self, NonNull};
 use core::marker::{Unpin, Unsize, PhantomData};
 use core::hash::{Hash, Hasher};
 use core::{isize, usize};
 use core::convert::From;
+use core::slice::from_raw_parts_mut;
 
-use alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
-use boxed::Box;
-use rc::is_dangling;
-use string::String;
-use vec::Vec;
+use crate::alloc::{Global, Alloc, Layout, box_free, handle_alloc_error};
+use crate::boxed::Box;
+use crate::rc::is_dangling;
+use crate::string::String;
+use crate::vec::Vec;
 
 /// A soft limit on the amount of references that may be made to an `Arc`.
 ///
@@ -251,7 +251,7 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Weak<U>> for Weak<T> {}
 
 #[stable(feature = "arc_weak", since = "1.4.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for Weak<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "(Weak)")
     }
 }
@@ -413,6 +413,27 @@ impl<T: ?Sized> Arc<T> {
         }
     }
 
+    /// Consumes the `Arc`, returning the wrapped pointer as `NonNull<T>`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(rc_into_raw_non_null)]
+    ///
+    /// use std::sync::Arc;
+    ///
+    /// let x = Arc::new(10);
+    /// let ptr = Arc::into_raw_non_null(x);
+    /// let deref = unsafe { *ptr.as_ref() };
+    /// assert_eq!(deref, 10);
+    /// ```
+    #[unstable(feature = "rc_into_raw_non_null", issue = "47336")]
+    #[inline]
+    pub fn into_raw_non_null(this: Self) -> NonNull<T> {
+        // safe because Arc guarantees its pointer is non-null
+        unsafe { NonNull::new_unchecked(Arc::into_raw(this) as *mut _) }
+    }
+
     /// Creates a new [`Weak`][weak] pointer to this value.
     ///
     /// [weak]: struct.Weak.html
@@ -539,7 +560,7 @@ impl<T: ?Sized> Arc<T> {
 
     #[inline]
     #[stable(feature = "ptr_eq", since = "1.17.0")]
-    /// Returns true if the two `Arc`s point to the same value (not
+    /// Returns `true` if the two `Arc`s point to the same value (not
     /// just values that compare as equal).
     ///
     /// # Examples
@@ -651,8 +672,6 @@ impl<T: Clone> ArcFromSlice<T> for Arc<[T]> {
 
         impl<T> Drop for Guard<T> {
             fn drop(&mut self) {
-                use core::slice::from_raw_parts_mut;
-
                 unsafe {
                     let slice = from_raw_parts_mut(self.elems, self.n_elems);
                     ptr::drop_in_place(slice);
@@ -1117,8 +1136,63 @@ impl<T: ?Sized> Weak<T> {
         }
     }
 
-    /// Return `None` when the pointer is dangling and there is no allocated `ArcInner`,
-    /// i.e., this `Weak` was created by `Weak::new`
+    /// Gets the number of strong (`Arc`) pointers pointing to this value.
+    ///
+    /// If `self` was created using [`Weak::new`], this will return 0.
+    ///
+    /// [`Weak::new`]: #method.new
+    #[unstable(feature = "weak_counts", issue = "57977")]
+    pub fn strong_count(&self) -> usize {
+        if let Some(inner) = self.inner() {
+            inner.strong.load(SeqCst)
+        } else {
+            0
+        }
+    }
+
+    /// Gets an approximation of the number of `Weak` pointers pointing to this
+    /// value.
+    ///
+    /// If `self` was created using [`Weak::new`], this will return 0. If not,
+    /// the returned value is at least 1, since `self` still points to the
+    /// value.
+    ///
+    /// # Accuracy
+    ///
+    /// Due to implementation details, the returned value can be off by 1 in
+    /// either direction when other threads are manipulating any `Arc`s or
+    /// `Weak`s pointing to the same value.
+    ///
+    /// [`Weak::new`]: #method.new
+    #[unstable(feature = "weak_counts", issue = "57977")]
+    pub fn weak_count(&self) -> Option<usize> {
+        // Due to the implicit weak pointer added when any strong pointers are
+        // around, we cannot implement `weak_count` correctly since it
+        // necessarily requires accessing the strong count and weak count in an
+        // unsynchronized fashion. So this version is a bit racy.
+        self.inner().map(|inner| {
+            let strong = inner.strong.load(SeqCst);
+            let weak = inner.weak.load(SeqCst);
+            if strong == 0 {
+                // If the last `Arc` has *just* been dropped, it might not yet
+                // have removed the implicit weak count, so the value we get
+                // here might be 1 too high.
+                weak
+            } else {
+                // As long as there's still at least 1 `Arc` around, subtract
+                // the implicit weak pointer.
+                // Note that the last `Arc` might get dropped between the 2
+                // loads we do above, removing the implicit weak pointer. This
+                // means that the value might be 1 too low here. In order to not
+                // return 0 here (which would happen if we're the only weak
+                // pointer), we guard against that specifically.
+                cmp::max(1, weak - 1)
+            }
+        })
+    }
+
+    /// Returns `None` when the pointer is dangling and there is no allocated `ArcInner`,
+    /// (i.e., when this `Weak` was created by `Weak::new`).
     #[inline]
     fn inner(&self) -> Option<&ArcInner<T>> {
         if is_dangling(self.ptr) {
@@ -1128,7 +1202,7 @@ impl<T: ?Sized> Weak<T> {
         }
     }
 
-    /// Returns true if the two `Weak`s point to the same value (not just values
+    /// Returns `true` if the two `Weak`s point to the same value (not just values
     /// that compare as equal).
     ///
     /// # Notes
@@ -1474,21 +1548,21 @@ impl<T: ?Sized + Eq> Eq for Arc<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Display> fmt::Display for Arc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized + fmt::Debug> fmt::Debug for Arc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> fmt::Pointer for Arc<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Pointer::fmt(&(&**self as *const T), f)
     }
 }
@@ -1525,7 +1599,7 @@ impl<T> From<T> for Arc<T> {
 }
 
 #[stable(feature = "shared_from_slice", since = "1.21.0")]
-impl<'a, T: Clone> From<&'a [T]> for Arc<[T]> {
+impl<T: Clone> From<&[T]> for Arc<[T]> {
     #[inline]
     fn from(v: &[T]) -> Arc<[T]> {
         <Self as ArcFromSlice<T>>::from_slice(v)
@@ -1533,7 +1607,7 @@ impl<'a, T: Clone> From<&'a [T]> for Arc<[T]> {
 }
 
 #[stable(feature = "shared_from_slice", since = "1.21.0")]
-impl<'a> From<&'a str> for Arc<str> {
+impl From<&str> for Arc<str> {
     #[inline]
     fn from(v: &str) -> Arc<str> {
         let arc = Arc::<[u8]>::from(v.as_bytes());
@@ -1579,16 +1653,14 @@ mod tests {
     use std::sync::mpsc::channel;
     use std::mem::drop;
     use std::ops::Drop;
-    use std::option::Option;
-    use std::option::Option::{None, Some};
-    use std::sync::atomic;
-    use std::sync::atomic::Ordering::{Acquire, SeqCst};
+    use std::option::Option::{self, None, Some};
+    use std::sync::atomic::{self, Ordering::{Acquire, SeqCst}};
     use std::thread;
     use std::sync::Mutex;
     use std::convert::From;
 
     use super::{Arc, Weak};
-    use vec::Vec;
+    use crate::vec::Vec;
 
     struct Canary(*mut atomic::AtomicUsize);
 
@@ -1636,6 +1708,33 @@ mod tests {
         assert!(Arc::get_mut(&mut x).is_none());
     }
 
+    #[test]
+    fn weak_counts() {
+        assert_eq!(Weak::weak_count(&Weak::<u64>::new()), None);
+        assert_eq!(Weak::strong_count(&Weak::<u64>::new()), 0);
+
+        let a = Arc::new(0);
+        let w = Arc::downgrade(&a);
+        assert_eq!(Weak::strong_count(&w), 1);
+        assert_eq!(Weak::weak_count(&w), Some(1));
+        let w2 = w.clone();
+        assert_eq!(Weak::strong_count(&w), 1);
+        assert_eq!(Weak::weak_count(&w), Some(2));
+        assert_eq!(Weak::strong_count(&w2), 1);
+        assert_eq!(Weak::weak_count(&w2), Some(2));
+        drop(w);
+        assert_eq!(Weak::strong_count(&w2), 1);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        let a2 = a.clone();
+        assert_eq!(Weak::strong_count(&w2), 2);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        drop(a2);
+        drop(a);
+        assert_eq!(Weak::strong_count(&w2), 0);
+        assert_eq!(Weak::weak_count(&w2), Some(1));
+        drop(w2);
+    }
+
     #[test]
     fn try_unwrap() {
         let x = Arc::new(3);
diff --git a/src/liballoc/task.rs b/src/liballoc/task.rs
deleted file mode 100644
index 604c56dd01762..0000000000000
--- a/src/liballoc/task.rs
+++ /dev/null
@@ -1,130 +0,0 @@
-//! Types and Traits for working with asynchronous tasks.
-
-pub use core::task::*;
-
-#[cfg(all(target_has_atomic = "ptr", target_has_atomic = "cas"))]
-pub use self::if_arc::*;
-
-#[cfg(all(target_has_atomic = "ptr", target_has_atomic = "cas"))]
-mod if_arc {
-    use super::*;
-    use core::marker::PhantomData;
-    use core::mem;
-    use core::ptr::{self, NonNull};
-    use sync::Arc;
-
-    /// A way of waking up a specific task.
-    ///
-    /// Any task executor must provide a way of signaling that a task it owns
-    /// is ready to be `poll`ed again. Executors do so by implementing this trait.
-    pub trait Wake: Send + Sync {
-        /// Indicates that the associated task is ready to make progress and should
-        /// be `poll`ed.
-        ///
-        /// Executors generally maintain a queue of "ready" tasks; `wake` should place
-        /// the associated task onto this queue.
-        fn wake(arc_self: &Arc<Self>);
-
-        /// Indicates that the associated task is ready to make progress and should
-        /// be `poll`ed. This function is like `wake`, but can only be called from the
-        /// thread on which this `Wake` was created.
-        ///
-        /// Executors generally maintain a queue of "ready" tasks; `wake_local` should place
-        /// the associated task onto this queue.
-        #[inline]
-        unsafe fn wake_local(arc_self: &Arc<Self>) {
-            Self::wake(arc_self);
-        }
-    }
-
-    #[cfg(all(target_has_atomic = "ptr", target_has_atomic = "cas"))]
-    struct ArcWrapped<T>(PhantomData<T>);
-
-    unsafe impl<T: Wake + 'static> UnsafeWake for ArcWrapped<T> {
-        #[inline]
-        unsafe fn clone_raw(&self) -> Waker {
-            let me: *const ArcWrapped<T> = self;
-            let arc = (*(&me as *const *const ArcWrapped<T> as *const Arc<T>)).clone();
-            Waker::from(arc)
-        }
-
-        #[inline]
-        unsafe fn drop_raw(&self) {
-            let mut me: *const ArcWrapped<T> = self;
-            let me = &mut me as *mut *const ArcWrapped<T> as *mut Arc<T>;
-            ptr::drop_in_place(me);
-        }
-
-        #[inline]
-        unsafe fn wake(&self) {
-            let me: *const ArcWrapped<T> = self;
-            T::wake(&*(&me as *const *const ArcWrapped<T> as *const Arc<T>))
-        }
-
-        #[inline]
-        unsafe fn wake_local(&self) {
-            let me: *const ArcWrapped<T> = self;
-            T::wake_local(&*(&me as *const *const ArcWrapped<T> as *const Arc<T>))
-        }
-    }
-
-    impl<T> From<Arc<T>> for Waker
-        where T: Wake + 'static,
-    {
-        fn from(rc: Arc<T>) -> Self {
-            unsafe {
-                let ptr = mem::transmute::<Arc<T>, NonNull<ArcWrapped<T>>>(rc);
-                Waker::new(ptr)
-            }
-        }
-    }
-
-    /// Creates a `LocalWaker` from a local `wake`.
-    ///
-    /// This function requires that `wake` is "local" (created on the current thread).
-    /// The resulting `LocalWaker` will call `wake.wake_local()` when awoken, and
-    /// will call `wake.wake()` if awoken after being converted to a `Waker`.
-    #[inline]
-    pub unsafe fn local_waker<W: Wake + 'static>(wake: Arc<W>) -> LocalWaker {
-        let ptr = mem::transmute::<Arc<W>, NonNull<ArcWrapped<W>>>(wake);
-        LocalWaker::new(ptr)
-    }
-
-    struct NonLocalAsLocal<T>(ArcWrapped<T>);
-
-    unsafe impl<T: Wake + 'static> UnsafeWake for NonLocalAsLocal<T> {
-        #[inline]
-        unsafe fn clone_raw(&self) -> Waker {
-            self.0.clone_raw()
-        }
-
-        #[inline]
-        unsafe fn drop_raw(&self) {
-            self.0.drop_raw()
-        }
-
-        #[inline]
-        unsafe fn wake(&self) {
-            self.0.wake()
-        }
-
-        #[inline]
-        unsafe fn wake_local(&self) {
-            // Since we're nonlocal, we can't call wake_local
-            self.0.wake()
-        }
-    }
-
-    /// Creates a `LocalWaker` from a non-local `wake`.
-    ///
-    /// This function is similar to `local_waker`, but does not require that `wake`
-    /// is local to the current thread. The resulting `LocalWaker` will call
-    /// `wake.wake()` when awoken.
-    #[inline]
-    pub fn local_waker_from_nonlocal<W: Wake + 'static>(wake: Arc<W>) -> LocalWaker {
-        unsafe {
-            let ptr = mem::transmute::<Arc<W>, NonNull<NonLocalAsLocal<W>>>(wake);
-            LocalWaker::new(ptr)
-        }
-    }
-}
diff --git a/src/liballoc/tests/binary_heap.rs b/src/liballoc/tests/binary_heap.rs
index 6af1cf4080947..1d4a3edc1ac42 100644
--- a/src/liballoc/tests/binary_heap.rs
+++ b/src/liballoc/tests/binary_heap.rs
@@ -2,7 +2,7 @@ use std::cmp;
 use std::collections::BinaryHeap;
 use std::collections::binary_heap::{Drain, PeekMut};
 use std::panic::{self, AssertUnwindSafe};
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
 use rand::{thread_rng, seq::SliceRandom};
 
@@ -282,8 +282,9 @@ fn assert_covariance() {
 //
 // Destructors must be called exactly once per element.
 #[test]
+#[cfg(not(miri))] // Miri does not support panics
 fn panic_safe() {
-    static DROP_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
+    static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0);
 
     #[derive(Eq, PartialEq, Ord, Clone, Debug)]
     struct PanicOrd<T>(T, bool);
diff --git a/src/liballoc/tests/btree/map.rs b/src/liballoc/tests/btree/map.rs
index 05e0bdffaa86b..f14750089c956 100644
--- a/src/liballoc/tests/btree/map.rs
+++ b/src/liballoc/tests/btree/map.rs
@@ -2,14 +2,17 @@ use std::collections::BTreeMap;
 use std::collections::btree_map::Entry::{Occupied, Vacant};
 use std::ops::Bound::{self, Excluded, Included, Unbounded};
 use std::rc::Rc;
-
 use std::iter::FromIterator;
+
 use super::DeterministicRng;
 
 #[test]
 fn test_basic_large() {
     let mut map = BTreeMap::new();
+    #[cfg(not(miri))] // Miri is too slow
     let size = 10000;
+    #[cfg(miri)]
+    let size = 200;
     assert_eq!(map.len(), 0);
 
     for i in 0..size {
@@ -69,7 +72,10 @@ fn test_basic_small() {
 
 #[test]
 fn test_iter() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 10000;
+    #[cfg(miri)]
+    let size = 200;
 
     // Forwards
     let mut map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
@@ -91,7 +97,10 @@ fn test_iter() {
 
 #[test]
 fn test_iter_rev() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 10000;
+    #[cfg(miri)]
+    let size = 200;
 
     // Forwards
     let mut map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
@@ -127,7 +136,10 @@ fn test_values_mut() {
 
 #[test]
 fn test_iter_mixed() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 10000;
+    #[cfg(miri)]
+    let size = 200;
 
     // Forwards
     let mut map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
@@ -199,7 +211,7 @@ fn test_range_inclusive() {
 
 #[test]
 fn test_range_inclusive_max_value() {
-    let max = ::std::usize::MAX;
+    let max = std::usize::MAX;
     let map: BTreeMap<_, _> = vec![(max, 0)].into_iter().collect();
 
     assert_eq!(map.range(max..=max).collect::<Vec<_>>(), &[(&max, &0)]);
@@ -214,6 +226,7 @@ fn test_range_equal_empty_cases() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_range_equal_excluded() {
     let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect();
     map.range((Excluded(2), Excluded(2)));
@@ -221,6 +234,7 @@ fn test_range_equal_excluded() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_range_backwards_1() {
     let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect();
     map.range((Included(3), Included(2)));
@@ -228,6 +242,7 @@ fn test_range_backwards_1() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_range_backwards_2() {
     let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect();
     map.range((Included(3), Excluded(2)));
@@ -235,6 +250,7 @@ fn test_range_backwards_2() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_range_backwards_3() {
     let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect();
     map.range((Excluded(3), Included(2)));
@@ -242,6 +258,7 @@ fn test_range_backwards_3() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_range_backwards_4() {
     let map: BTreeMap<_, _> = (0..5).map(|i| (i, i)).collect();
     map.range((Excluded(3), Excluded(2)));
@@ -249,7 +266,10 @@ fn test_range_backwards_4() {
 
 #[test]
 fn test_range_1000() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 1000;
+    #[cfg(miri)]
+    let size = 200;
     let map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
 
     fn test(map: &BTreeMap<u32, u32>, size: u32, min: Bound<&u32>, max: Bound<&u32>) {
@@ -286,7 +306,10 @@ fn test_range_borrowed_key() {
 
 #[test]
 fn test_range() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 200;
+    #[cfg(miri)]
+    let size = 30;
     let map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
 
     for i in 0..size {
@@ -305,7 +328,10 @@ fn test_range() {
 
 #[test]
 fn test_range_mut() {
+    #[cfg(not(miri))] // Miri is too slow
     let size = 200;
+    #[cfg(miri)]
+    let size = 30;
     let mut map: BTreeMap<_, _> = (0..size).map(|i| (i, i)).collect();
 
     for i in 0..size {
@@ -479,7 +505,10 @@ fn test_bad_zst() {
 #[test]
 fn test_clone() {
     let mut map = BTreeMap::new();
+    #[cfg(not(miri))] // Miri is too slow
     let size = 100;
+    #[cfg(miri)]
+    let size = 30;
     assert_eq!(map.len(), 0);
 
     for i in 0..size {
@@ -631,6 +660,7 @@ create_append_test!(test_append_145, 145);
 create_append_test!(test_append_170, 170);
 create_append_test!(test_append_181, 181);
 create_append_test!(test_append_239, 239);
+#[cfg(not(miri))] // Miri is too slow
 create_append_test!(test_append_1700, 1700);
 
 fn rand_data(len: usize) -> Vec<(u32, u32)> {
diff --git a/src/liballoc/tests/btree/set.rs b/src/liballoc/tests/btree/set.rs
index e24c04fd8acb3..4f5168f1ce572 100644
--- a/src/liballoc/tests/btree/set.rs
+++ b/src/liballoc/tests/btree/set.rs
@@ -1,6 +1,6 @@
 use std::collections::BTreeSet;
-
 use std::iter::FromIterator;
+
 use super::DeterministicRng;
 
 #[test]
@@ -15,6 +15,8 @@ fn test_clone_eq() {
 
 #[test]
 fn test_hash() {
+    use crate::hash;
+
     let mut x = BTreeSet::new();
     let mut y = BTreeSet::new();
 
@@ -26,7 +28,7 @@ fn test_hash() {
     y.insert(2);
     y.insert(1);
 
-    assert!(::hash(&x) == ::hash(&y));
+    assert!(hash(&x) == hash(&y));
 }
 
 fn check<F>(a: &[i32], b: &[i32], expected: &[i32], f: F)
diff --git a/src/liballoc/tests/heap.rs b/src/liballoc/tests/heap.rs
index 24eea1d294965..c225ebfa96b91 100644
--- a/src/liballoc/tests/heap.rs
+++ b/src/liballoc/tests/heap.rs
@@ -1,6 +1,6 @@
 use std::alloc::{Global, Alloc, Layout, System};
 
-/// https://github.com/rust-lang/rust/issues/45955
+/// Issue #45955.
 #[test]
 fn alloc_system_overaligned_request() {
     check_overalign_requests(System)
diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs
index a76fd87a1a92d..2361a7db1f7a7 100644
--- a/src/liballoc/tests/lib.rs
+++ b/src/liballoc/tests/lib.rs
@@ -4,8 +4,6 @@
 #![feature(exact_size_is_empty)]
 #![feature(pattern)]
 #![feature(repeat_generic_slice)]
-#![feature(slice_sort_by_cached_key)]
-#![feature(str_escape)]
 #![feature(try_reserve)]
 #![feature(unboxed_closures)]
 #![feature(vecdeque_rotate)]
diff --git a/src/liballoc/tests/linked_list.rs b/src/liballoc/tests/linked_list.rs
index 6e775f9650d12..0fbfbdccd4537 100644
--- a/src/liballoc/tests/linked_list.rs
+++ b/src/liballoc/tests/linked_list.rs
@@ -241,10 +241,12 @@ fn test_eq() {
 
 #[test]
 fn test_hash() {
+    use crate::hash;
+
     let mut x = LinkedList::new();
     let mut y = LinkedList::new();
 
-    assert!(::hash(&x) == ::hash(&y));
+    assert!(hash(&x) == hash(&y));
 
     x.push_back(1);
     x.push_back(2);
@@ -254,7 +256,7 @@ fn test_hash() {
     y.push_front(2);
     y.push_front(1);
 
-    assert!(::hash(&x) == ::hash(&y));
+    assert!(hash(&x) == hash(&y));
 }
 
 #[test]
diff --git a/src/liballoc/tests/slice.rs b/src/liballoc/tests/slice.rs
index 8ecd17236c048..feba46b0fad78 100644
--- a/src/liballoc/tests/slice.rs
+++ b/src/liballoc/tests/slice.rs
@@ -1,14 +1,13 @@
 use std::cell::Cell;
-use std::cmp::Ordering::{Equal, Greater, Less};
-use std::cmp::Ordering;
+use std::cmp::Ordering::{self, Equal, Greater, Less};
 use std::mem;
 use std::panic;
 use std::rc::Rc;
-use std::sync::atomic::Ordering::Relaxed;
-use std::sync::atomic::{ATOMIC_USIZE_INIT, AtomicUsize};
+use std::sync::atomic::{Ordering::Relaxed, AtomicUsize};
 use std::thread;
 
-use rand::{Rng, RngCore, thread_rng, seq::SliceRandom};
+use rand::{Rng, RngCore, thread_rng};
+use rand::seq::SliceRandom;
 use rand::distributions::Standard;
 
 fn square(n: usize) -> usize {
@@ -259,6 +258,7 @@ fn test_swap_remove() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_swap_remove_fail() {
     let mut v = vec![1];
     let _ = v.swap_remove(0);
@@ -390,6 +390,7 @@ fn test_reverse() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support entropy
 fn test_sort() {
     let mut rng = thread_rng();
 
@@ -466,6 +467,7 @@ fn test_sort() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support entropy
 fn test_sort_stability() {
     for len in (2..25).chain(500..510) {
         for _ in 0..10 {
@@ -476,7 +478,7 @@ fn test_sort_stability() {
             // the second item represents which occurrence of that
             // number this element is, i.e., the second elements
             // will occur in sorted order.
-            let mut orig: Vec<_> = (0..len)
+            let orig: Vec<_> = (0..len)
                 .map(|_| {
                     let n = thread_rng().gen::<usize>() % 10;
                     counts[n] += 1;
@@ -630,6 +632,7 @@ fn test_insert() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_insert_oob() {
     let mut a = vec![1, 2, 3];
     a.insert(4, 5);
@@ -654,6 +657,7 @@ fn test_remove() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_remove_fail() {
     let mut a = vec![1];
     let _ = a.remove(0);
@@ -935,6 +939,7 @@ fn test_windowsator() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_windowsator_0() {
     let v = &[1, 2, 3, 4];
     let _it = v.windows(0);
@@ -959,6 +964,7 @@ fn test_chunksator() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_chunksator_0() {
     let v = &[1, 2, 3, 4];
     let _it = v.chunks(0);
@@ -983,6 +989,7 @@ fn test_chunks_exactator() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_chunks_exactator_0() {
     let v = &[1, 2, 3, 4];
     let _it = v.chunks_exact(0);
@@ -1007,6 +1014,7 @@ fn test_rchunksator() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_rchunksator_0() {
     let v = &[1, 2, 3, 4];
     let _it = v.rchunks(0);
@@ -1031,6 +1039,7 @@ fn test_rchunks_exactator() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_rchunks_exactator_0() {
     let v = &[1, 2, 3, 4];
     let _it = v.rchunks_exact(0);
@@ -1083,6 +1092,7 @@ fn test_vec_default() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_overflow_does_not_cause_segfault() {
     let mut v = vec![];
     v.reserve_exact(!0);
@@ -1092,6 +1102,7 @@ fn test_overflow_does_not_cause_segfault() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_overflow_does_not_cause_segfault_managed() {
     let mut v = vec![Rc::new(1)];
     v.reserve_exact(!0);
@@ -1267,6 +1278,7 @@ fn test_mut_chunks_rev() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mut_chunks_0() {
     let mut v = [1, 2, 3, 4];
     let _it = v.chunks_mut(0);
@@ -1299,6 +1311,7 @@ fn test_mut_chunks_exact_rev() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mut_chunks_exact_0() {
     let mut v = [1, 2, 3, 4];
     let _it = v.chunks_exact_mut(0);
@@ -1331,6 +1344,7 @@ fn test_mut_rchunks_rev() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mut_rchunks_0() {
     let mut v = [1, 2, 3, 4];
     let _it = v.rchunks_mut(0);
@@ -1363,6 +1377,7 @@ fn test_mut_rchunks_exact_rev() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mut_rchunks_exact_0() {
     let mut v = [1, 2, 3, 4];
     let _it = v.rchunks_exact_mut(0);
@@ -1396,6 +1411,7 @@ fn test_box_slice_clone() {
 #[test]
 #[allow(unused_must_use)] // here, we care about the side effects of `.clone()`
 #[cfg_attr(target_os = "emscripten", ignore)]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_box_slice_clone_panics() {
     use std::sync::Arc;
     use std::sync::atomic::{AtomicUsize, Ordering};
@@ -1460,6 +1476,7 @@ fn test_copy_from_slice() {
 
 #[test]
 #[should_panic(expected = "destination and source slices have different lengths")]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_copy_from_slice_dst_longer() {
     let src = [0, 1, 2, 3];
     let mut dst = [0; 5];
@@ -1468,6 +1485,7 @@ fn test_copy_from_slice_dst_longer() {
 
 #[test]
 #[should_panic(expected = "destination and source slices have different lengths")]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_copy_from_slice_dst_shorter() {
     let src = [0, 1, 2, 3];
     let mut dst = [0; 3];
@@ -1500,7 +1518,7 @@ static DROP_COUNTS: [AtomicUsize; MAX_LEN] = [
     AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
 ];
 
-static VERSIONS: AtomicUsize = ATOMIC_USIZE_INIT;
+static VERSIONS: AtomicUsize = AtomicUsize::new(0);
 
 #[derive(Clone, Eq)]
 struct DropCounter {
@@ -1587,6 +1605,7 @@ thread_local!(static SILENCE_PANIC: Cell<bool> = Cell::new(false));
 
 #[test]
 #[cfg_attr(target_os = "emscripten", ignore)] // no threads
+#[cfg(not(miri))] // Miri does not support panics
 fn panic_safe() {
     let prev = panic::take_hook();
     panic::set_hook(Box::new(move |info| {
diff --git a/src/liballoc/tests/str.rs b/src/liballoc/tests/str.rs
index 66a1b947a7d3a..b33a564218888 100644
--- a/src/liballoc/tests/str.rs
+++ b/src/liballoc/tests/str.rs
@@ -166,6 +166,7 @@ fn test_join_for_different_lengths_with_long_separator() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn test_unsafe_slice() {
     assert_eq!("ab", unsafe {"abc".get_unchecked(0..2)});
     assert_eq!("bc", unsafe {"abc".get_unchecked(1..3)});
@@ -350,6 +351,7 @@ mod slice_index {
     //  to be used in `should_panic`)
     #[test]
     #[should_panic(expected = "out of bounds")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn assert_range_eq_can_fail_by_panic() {
         assert_range_eq!("abc", 0..5, "abc");
     }
@@ -359,6 +361,7 @@ mod slice_index {
     //  to be used in `should_panic`)
     #[test]
     #[should_panic(expected = "==")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn assert_range_eq_can_fail_by_inequality() {
         assert_range_eq!("abc", 0..2, "abc");
     }
@@ -406,6 +409,7 @@ mod slice_index {
 
                 #[test]
                 #[should_panic(expected = $expect_msg)]
+                #[cfg(not(miri))] // Miri does not support panics
                 fn index_fail() {
                     let v: String = $data.into();
                     let v: &str = &v;
@@ -414,6 +418,7 @@ mod slice_index {
 
                 #[test]
                 #[should_panic(expected = $expect_msg)]
+                #[cfg(not(miri))] // Miri does not support panics
                 fn index_mut_fail() {
                     let mut v: String = $data.into();
                     let v: &mut str = &mut v;
@@ -483,6 +488,7 @@ mod slice_index {
 
     #[test]
     #[cfg(not(target_arch = "asmjs"))] // hits an OOM
+    #[cfg(not(miri))] // Miri is too slow
     fn simple_big() {
         fn a_million_letter_x() -> String {
             let mut i = 0;
@@ -508,6 +514,7 @@ mod slice_index {
 
     #[test]
     #[should_panic]
+    #[cfg(not(miri))] // Miri does not support panics
     fn test_slice_fail() {
         &"中华Việt Nam"[0..2];
     }
@@ -584,7 +591,7 @@ mod slice_index {
     }
 
     mod boundary {
-        const DATA: &'static str = "abcαβγ";
+        const DATA: &str = "abcαβγ";
 
         const BAD_START: usize = 4;
         const GOOD_START: usize = 3;
@@ -648,7 +655,7 @@ mod slice_index {
         }
     }
 
-    const LOREM_PARAGRAPH: &'static str = "\
+    const LOREM_PARAGRAPH: &str = "\
     Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse quis lorem \
     sit amet dolor ultricies condimentum. Praesent iaculis purus elit, ac malesuada \
     quam malesuada in. Duis sed orci eros. Suspendisse sit amet magna mollis, mollis \
@@ -659,12 +666,14 @@ mod slice_index {
     // check the panic includes the prefix of the sliced string
     #[test]
     #[should_panic(expected="byte index 1024 is out of bounds of `Lorem ipsum dolor sit amet")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn test_slice_fail_truncated_1() {
         &LOREM_PARAGRAPH[..1024];
     }
     // check the truncation in the panic message
     #[test]
     #[should_panic(expected="luctus, im`[...]")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn test_slice_fail_truncated_2() {
         &LOREM_PARAGRAPH[..1024];
     }
@@ -679,6 +688,7 @@ fn test_str_slice_rangetoinclusive_ok() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_str_slice_rangetoinclusive_notok() {
     let s = "abcαβγ";
     &s[..=3];
@@ -694,6 +704,7 @@ fn test_str_slicemut_rangetoinclusive_ok() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_str_slicemut_rangetoinclusive_notok() {
     let mut s = "abcαβγ".to_owned();
     let s: &mut str = &mut s;
@@ -883,6 +894,7 @@ fn test_as_bytes() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_as_bytes_fail() {
     // Don't double free. (I'm not sure if this exercises the
     // original problem code path anymore.)
@@ -972,6 +984,7 @@ fn test_split_at_mut() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_split_at_boundscheck() {
     let s = "ศไทย中华Việt Nam";
     s.split_at(1);
@@ -979,15 +992,15 @@ fn test_split_at_boundscheck() {
 
 #[test]
 fn test_escape_unicode() {
-    assert_eq!("abc".escape_unicode(), "\\u{61}\\u{62}\\u{63}");
-    assert_eq!("a c".escape_unicode(), "\\u{61}\\u{20}\\u{63}");
-    assert_eq!("\r\n\t".escape_unicode(), "\\u{d}\\u{a}\\u{9}");
-    assert_eq!("'\"\\".escape_unicode(), "\\u{27}\\u{22}\\u{5c}");
-    assert_eq!("\x00\x01\u{fe}\u{ff}".escape_unicode(), "\\u{0}\\u{1}\\u{fe}\\u{ff}");
-    assert_eq!("\u{100}\u{ffff}".escape_unicode(), "\\u{100}\\u{ffff}");
-    assert_eq!("\u{10000}\u{10ffff}".escape_unicode(), "\\u{10000}\\u{10ffff}");
-    assert_eq!("ab\u{fb00}".escape_unicode(), "\\u{61}\\u{62}\\u{fb00}");
-    assert_eq!("\u{1d4ea}\r".escape_unicode(), "\\u{1d4ea}\\u{d}");
+    assert_eq!("abc".escape_unicode().to_string(), "\\u{61}\\u{62}\\u{63}");
+    assert_eq!("a c".escape_unicode().to_string(), "\\u{61}\\u{20}\\u{63}");
+    assert_eq!("\r\n\t".escape_unicode().to_string(), "\\u{d}\\u{a}\\u{9}");
+    assert_eq!("'\"\\".escape_unicode().to_string(), "\\u{27}\\u{22}\\u{5c}");
+    assert_eq!("\x00\x01\u{fe}\u{ff}".escape_unicode().to_string(), "\\u{0}\\u{1}\\u{fe}\\u{ff}");
+    assert_eq!("\u{100}\u{ffff}".escape_unicode().to_string(), "\\u{100}\\u{ffff}");
+    assert_eq!("\u{10000}\u{10ffff}".escape_unicode().to_string(), "\\u{10000}\\u{10ffff}");
+    assert_eq!("ab\u{fb00}".escape_unicode().to_string(), "\\u{61}\\u{62}\\u{fb00}");
+    assert_eq!("\u{1d4ea}\r".escape_unicode().to_string(), "\\u{1d4ea}\\u{d}");
 }
 
 #[test]
@@ -998,31 +1011,32 @@ fn test_escape_debug() {
     // they are escaped. However, when the character is unescaped (e.g., for
     // printable characters), only a single backslash appears (as the character
     // itself appears in the debug string).
-    assert_eq!("abc".escape_debug(), "abc");
-    assert_eq!("a c".escape_debug(), "a c");
-    assert_eq!("éèê".escape_debug(), "éèê");
-    assert_eq!("\r\n\t".escape_debug(), "\\r\\n\\t");
-    assert_eq!("'\"\\".escape_debug(), "\\'\\\"\\\\");
-    assert_eq!("\u{7f}\u{ff}".escape_debug(), "\\u{7f}\u{ff}");
-    assert_eq!("\u{100}\u{ffff}".escape_debug(), "\u{100}\\u{ffff}");
-    assert_eq!("\u{10000}\u{10ffff}".escape_debug(), "\u{10000}\\u{10ffff}");
-    assert_eq!("ab\u{200b}".escape_debug(), "ab\\u{200b}");
-    assert_eq!("\u{10d4ea}\r".escape_debug(), "\\u{10d4ea}\\r");
-    assert_eq!("\u{301}a\u{301}bé\u{e000}".escape_debug(), "\\u{301}a\u{301}bé\\u{e000}");
+    assert_eq!("abc".escape_debug().to_string(), "abc");
+    assert_eq!("a c".escape_debug().to_string(), "a c");
+    assert_eq!("éèê".escape_debug().to_string(), "éèê");
+    assert_eq!("\r\n\t".escape_debug().to_string(), "\\r\\n\\t");
+    assert_eq!("'\"\\".escape_debug().to_string(), "\\'\\\"\\\\");
+    assert_eq!("\u{7f}\u{ff}".escape_debug().to_string(), "\\u{7f}\u{ff}");
+    assert_eq!("\u{100}\u{ffff}".escape_debug().to_string(), "\u{100}\\u{ffff}");
+    assert_eq!("\u{10000}\u{10ffff}".escape_debug().to_string(), "\u{10000}\\u{10ffff}");
+    assert_eq!("ab\u{200b}".escape_debug().to_string(), "ab\\u{200b}");
+    assert_eq!("\u{10d4ea}\r".escape_debug().to_string(), "\\u{10d4ea}\\r");
+    assert_eq!("\u{301}a\u{301}bé\u{e000}".escape_debug().to_string(),
+               "\\u{301}a\u{301}bé\\u{e000}");
 }
 
 #[test]
 fn test_escape_default() {
-    assert_eq!("abc".escape_default(), "abc");
-    assert_eq!("a c".escape_default(), "a c");
-    assert_eq!("éèê".escape_default(), "\\u{e9}\\u{e8}\\u{ea}");
-    assert_eq!("\r\n\t".escape_default(), "\\r\\n\\t");
-    assert_eq!("'\"\\".escape_default(), "\\'\\\"\\\\");
-    assert_eq!("\u{7f}\u{ff}".escape_default(), "\\u{7f}\\u{ff}");
-    assert_eq!("\u{100}\u{ffff}".escape_default(), "\\u{100}\\u{ffff}");
-    assert_eq!("\u{10000}\u{10ffff}".escape_default(), "\\u{10000}\\u{10ffff}");
-    assert_eq!("ab\u{200b}".escape_default(), "ab\\u{200b}");
-    assert_eq!("\u{10d4ea}\r".escape_default(), "\\u{10d4ea}\\r");
+    assert_eq!("abc".escape_default().to_string(), "abc");
+    assert_eq!("a c".escape_default().to_string(), "a c");
+    assert_eq!("éèê".escape_default().to_string(), "\\u{e9}\\u{e8}\\u{ea}");
+    assert_eq!("\r\n\t".escape_default().to_string(), "\\r\\n\\t");
+    assert_eq!("'\"\\".escape_default().to_string(), "\\'\\\"\\\\");
+    assert_eq!("\u{7f}\u{ff}".escape_default().to_string(), "\\u{7f}\\u{ff}");
+    assert_eq!("\u{100}\u{ffff}".escape_default().to_string(), "\\u{100}\\u{ffff}");
+    assert_eq!("\u{10000}\u{10ffff}".escape_default().to_string(), "\\u{10000}\\u{10ffff}");
+    assert_eq!("ab\u{200b}".escape_default().to_string(), "ab\\u{200b}");
+    assert_eq!("\u{10d4ea}\r".escape_default().to_string(), "\\u{10d4ea}\\r");
 }
 
 #[test]
@@ -1066,9 +1080,10 @@ fn test_rev_iterator() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn test_chars_decoding() {
     let mut bytes = [0; 4];
-    for c in (0..0x110000).filter_map(::std::char::from_u32) {
+    for c in (0..0x110000).filter_map(std::char::from_u32) {
         let s = c.encode_utf8(&mut bytes);
         if Some(c) != s.chars().next() {
             panic!("character {:x}={} does not decode correctly", c as u32, c);
@@ -1077,9 +1092,10 @@ fn test_chars_decoding() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn test_chars_rev_decoding() {
     let mut bytes = [0; 4];
-    for c in (0..0x110000).filter_map(::std::char::from_u32) {
+    for c in (0..0x110000).filter_map(std::char::from_u32) {
         let s = c.encode_utf8(&mut bytes);
         if Some(c) != s.chars().rev().next() {
             panic!("character {:x}={} does not decode correctly", c as u32, c);
@@ -1365,6 +1381,7 @@ fn test_bool_from_str() {
     assert_eq!("not even a boolean".parse::<bool>().ok(), None);
 }
 
+#[cfg(not(miri))] // Miri is too slow
 fn check_contains_all_substrings(s: &str) {
     assert!(s.contains(""));
     for i in 0..s.len() {
@@ -1375,6 +1392,7 @@ fn check_contains_all_substrings(s: &str) {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn strslice_issue_16589() {
     assert!("bananas".contains("nana"));
 
@@ -1391,6 +1409,7 @@ fn strslice_issue_16878() {
 
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn test_strslice_contains() {
     let x = "There are moments, Jeeves, when one asks oneself, 'Do trousers matter?'";
     check_contains_all_substrings(x);
@@ -1599,8 +1618,7 @@ fn test_repeat() {
 }
 
 mod pattern {
-    use std::str::pattern::Pattern;
-    use std::str::pattern::{Searcher, ReverseSearcher};
+    use std::str::pattern::{Pattern, Searcher, ReverseSearcher};
     use std::str::pattern::SearchStep::{self, Match, Reject, Done};
 
     macro_rules! make_test {
diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs
index 8a5bfca8b7db5..7e93d84fe3b97 100644
--- a/src/liballoc/tests/string.rs
+++ b/src/liballoc/tests/string.rs
@@ -21,7 +21,7 @@ impl<'a> IntoCow<'a, str> for &'a str {
 
 #[test]
 fn test_from_str() {
-    let owned: Option<::std::string::String> = "string".parse().ok();
+    let owned: Option<std::string::String> = "string".parse().ok();
     assert_eq!(owned.as_ref().map(|s| &**s), Some("string"));
 }
 
@@ -122,7 +122,7 @@ fn test_from_utf16() {
         let s_as_utf16 = s.encode_utf16().collect::<Vec<u16>>();
         let u_as_string = String::from_utf16(&u).unwrap();
 
-        assert!(::core::char::decode_utf16(u.iter().cloned()).all(|r| r.is_ok()));
+        assert!(core::char::decode_utf16(u.iter().cloned()).all(|r| r.is_ok()));
         assert_eq!(s_as_utf16, u);
 
         assert_eq!(u_as_string, s);
@@ -231,6 +231,7 @@ fn test_split_off_empty() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_split_off_past_end() {
     let orig = "Hello, world!";
     let mut split = String::from(orig);
@@ -239,6 +240,7 @@ fn test_split_off_past_end() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_split_off_mid_char() {
     let mut orig = String::from("山");
     orig.split_off(1);
@@ -287,6 +289,7 @@ fn test_str_truncate_invalid_len() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_str_truncate_split_codepoint() {
     let mut s = String::from("\u{FC}"); // ü
     s.truncate(1);
@@ -321,6 +324,7 @@ fn remove() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn remove_bad() {
     "ศ".to_string().remove(1);
 }
@@ -356,11 +360,13 @@ fn insert() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn insert_bad1() {
     "".to_string().insert(1, 't');
 }
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn insert_bad2() {
     "ệ".to_string().insert(1, 't');
 }
@@ -441,6 +447,7 @@ fn test_replace_range() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_replace_range_char_boundary() {
     let mut s = "Hello, 世界!".to_owned();
     s.replace_range(..8, "");
@@ -457,6 +464,7 @@ fn test_replace_range_inclusive_range() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_replace_range_out_of_bounds() {
     let mut s = String::from("12345");
     s.replace_range(5..6, "789");
@@ -464,6 +472,7 @@ fn test_replace_range_out_of_bounds() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_replace_range_inclusive_out_of_bounds() {
     let mut s = String::from("12345");
     s.replace_range(5..=5, "789");
@@ -523,6 +532,7 @@ fn test_reserve_exact() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support signalling OOM
 fn test_try_reserve() {
 
     // These are the interesting cases:
@@ -600,6 +610,7 @@ fn test_try_reserve() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support signalling OOM
 fn test_try_reserve_exact() {
 
     // This is exactly the same as test_try_reserve with the method changed.
diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs
index 0fdcf34c783a8..6e4ca1d90e642 100644
--- a/src/liballoc/tests/vec.rs
+++ b/src/liballoc/tests/vec.rs
@@ -1,3 +1,5 @@
+#![cfg(not(miri))]
+
 use std::borrow::Cow;
 use std::mem::size_of;
 use std::{usize, isize};
@@ -8,7 +10,7 @@ struct DropCounter<'a> {
     count: &'a mut u32,
 }
 
-impl<'a> Drop for DropCounter<'a> {
+impl Drop for DropCounter<'_> {
     fn drop(&mut self) {
         *self.count += 1;
     }
@@ -366,6 +368,7 @@ fn test_vec_truncate_drop() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_vec_truncate_fail() {
     struct BadElem(i32);
     impl Drop for BadElem {
@@ -389,6 +392,7 @@ fn test_index() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_index_out_of_bounds() {
     let vec = vec![1, 2, 3];
     let _ = vec[3];
@@ -396,6 +400,7 @@ fn test_index_out_of_bounds() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_slice_out_of_bounds_1() {
     let x = vec![1, 2, 3, 4, 5];
     &x[!0..];
@@ -403,6 +408,7 @@ fn test_slice_out_of_bounds_1() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_slice_out_of_bounds_2() {
     let x = vec![1, 2, 3, 4, 5];
     &x[..6];
@@ -410,6 +416,7 @@ fn test_slice_out_of_bounds_2() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_slice_out_of_bounds_3() {
     let x = vec![1, 2, 3, 4, 5];
     &x[!0..4];
@@ -417,6 +424,7 @@ fn test_slice_out_of_bounds_3() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_slice_out_of_bounds_4() {
     let x = vec![1, 2, 3, 4, 5];
     &x[1..6];
@@ -424,6 +432,7 @@ fn test_slice_out_of_bounds_4() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_slice_out_of_bounds_5() {
     let x = vec![1, 2, 3, 4, 5];
     &x[3..2];
@@ -431,6 +440,7 @@ fn test_slice_out_of_bounds_5() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_swap_remove_empty() {
     let mut vec = Vec::<i32>::new();
     vec.swap_remove(0);
@@ -501,6 +511,7 @@ fn test_drain_items_zero_sized() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_drain_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     v.drain(5..6);
@@ -574,6 +585,7 @@ fn test_drain_max_vec_size() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_drain_inclusive_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     v.drain(5..=5);
@@ -603,6 +615,7 @@ fn test_splice_inclusive_range() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_splice_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     let a = [10, 11, 12];
@@ -611,6 +624,7 @@ fn test_splice_out_of_bounds() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_splice_inclusive_out_of_bounds() {
     let mut v = vec![1, 2, 3, 4, 5];
     let a = [10, 11, 12];
@@ -638,7 +652,7 @@ fn test_splice_unbounded() {
 fn test_splice_forget() {
     let mut v = vec![1, 2, 3, 4, 5];
     let a = [10, 11, 12];
-    ::std::mem::forget(v.splice(2..4, a.iter().cloned()));
+    std::mem::forget(v.splice(2..4, a.iter().cloned()));
     assert_eq!(v, &[1, 2]);
 }
 
diff --git a/src/liballoc/tests/vec_deque.rs b/src/liballoc/tests/vec_deque.rs
index 76831ba65e3b8..16ddc1444fcf9 100644
--- a/src/liballoc/tests/vec_deque.rs
+++ b/src/liballoc/tests/vec_deque.rs
@@ -1,12 +1,13 @@
-use std::collections::VecDeque;
 use std::fmt::Debug;
-use std::collections::vec_deque::{Drain};
+use std::collections::{VecDeque, vec_deque::Drain};
 use std::collections::CollectionAllocErr::*;
 use std::mem::size_of;
 use std::{usize, isize};
 
-use self::Taggy::*;
-use self::Taggypar::*;
+use crate::hash;
+
+use Taggy::*;
+use Taggypar::*;
 
 #[test]
 fn test_simple() {
@@ -107,6 +108,7 @@ fn test_index() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_index_out_of_bounds() {
     let mut deq = VecDeque::new();
     for i in 1..4 {
@@ -583,7 +585,7 @@ fn test_hash() {
     y.push_back(2);
     y.push_back(3);
 
-    assert!(::hash(&x) == ::hash(&y));
+    assert!(hash(&x) == hash(&y));
 }
 
 #[test]
@@ -599,7 +601,7 @@ fn test_hash_after_rotation() {
             *elt -= 1;
         }
         ring.push_back(len - 1);
-        assert_eq!(::hash(&orig), ::hash(&ring));
+        assert_eq!(hash(&orig), hash(&ring));
         assert_eq!(orig, ring);
         assert_eq!(ring, orig);
     }
@@ -942,7 +944,10 @@ fn test_append_permutations() {
         out
     }
 
+    #[cfg(not(miri))] // Miri is too slow
     const MAX: usize = 5;
+    #[cfg(miri)]
+    const MAX: usize = 3;
 
     // Many different permutations of both the `VecDeque` getting appended to
     // and the one getting appended are generated to check `append`.
@@ -998,7 +1003,7 @@ struct DropCounter<'a> {
     count: &'a mut u32,
 }
 
-impl<'a> Drop for DropCounter<'a> {
+impl Drop for DropCounter<'_> {
     fn drop(&mut self) {
         *self.count += 1;
     }
@@ -1119,6 +1124,7 @@ fn test_reserve_exact_2() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support signalling OOM
 fn test_try_reserve() {
 
     // These are the interesting cases:
@@ -1220,6 +1226,7 @@ fn test_try_reserve() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri does not support signalling OOM
 fn test_try_reserve_exact() {
 
     // This is exactly the same as test_try_reserve with the method changed.
@@ -1433,3 +1440,104 @@ fn test_rotate_right_random() {
         }
     }
 }
+
+#[test]
+fn test_try_fold_empty() {
+    assert_eq!(Some(0), VecDeque::<u32>::new().iter().try_fold(0, |_, _| None));
+}
+
+#[test]
+fn test_try_fold_none() {
+    let v: VecDeque<u32> = (0..12).collect();
+    assert_eq!(None, v.into_iter().try_fold(0, |a, b|
+        if b < 11 { Some(a + b) } else { None }));
+}
+
+#[test]
+fn test_try_fold_ok() {
+    let v: VecDeque<u32> = (0..12).collect();
+    assert_eq!(Ok::<_, ()>(66), v.into_iter().try_fold(0, |a, b| Ok(a + b)));
+}
+
+#[test]
+fn test_try_fold_unit() {
+    let v: VecDeque<()> = std::iter::repeat(()).take(42).collect();
+    assert_eq!(Some(()), v.into_iter().try_fold((), |(), ()| Some(())));
+}
+
+
+#[test]
+fn test_try_fold_unit_none() {
+    let v: std::collections::VecDeque<()> = [(); 10].iter().cloned().collect();
+    let mut iter = v.into_iter();
+    assert!(iter.try_fold((), |_, _| None).is_none());
+    assert_eq!(iter.len(), 9);
+}
+
+#[test]
+fn test_try_fold_rotated() {
+    let mut v: VecDeque<_> = (0..12).collect();
+    for n in 0..10 {
+        if n & 1 == 0 {
+            v.rotate_left(n);
+        } else {
+            v.rotate_right(n);
+        }
+        assert_eq!(Ok::<_, ()>(66), v.iter().try_fold(0, |a, b| Ok(a + b)));
+    }
+}
+
+#[test]
+fn test_try_fold_moves_iter() {
+    let v: VecDeque<_> = [10, 20, 30, 40, 100, 60, 70, 80, 90].iter().collect();
+    let mut iter = v.into_iter();
+    assert_eq!(iter.try_fold(0_i8, |acc, &x| acc.checked_add(x)), None);
+    assert_eq!(iter.next(), Some(&60));
+}
+
+#[test]
+fn test_try_fold_exhaust_wrap() {
+    let mut v = VecDeque::with_capacity(7);
+    v.push_back(1);
+    v.push_back(1);
+    v.push_back(1);
+    v.pop_front();
+    v.pop_front();
+    let mut iter = v.iter();
+    let _ = iter.try_fold(0, |_, _| Some(1));
+    assert!(iter.is_empty());
+}
+
+#[test]
+fn test_try_fold_wraparound() {
+    let mut v = VecDeque::with_capacity(8);
+    v.push_back(7);
+    v.push_back(8);
+    v.push_back(9);
+    v.push_front(2);
+    v.push_front(1);
+    let mut iter = v.iter();
+    let _ = iter.find(|&&x| x == 2);
+    assert_eq!(Some(&7), iter.next());
+}
+
+#[test]
+fn test_try_rfold_rotated() {
+    let mut v: VecDeque<_> = (0..12).collect();
+    for n in 0..10 {
+        if n & 1 == 0 {
+            v.rotate_left(n);
+        } else {
+            v.rotate_right(n);
+        }
+        assert_eq!(Ok::<_, ()>(66), v.iter().try_rfold(0, |a, b| Ok(a + b)));
+    }
+}
+
+#[test]
+fn test_try_rfold_moves_iter() {
+    let v : VecDeque<_> = [10, 20, 30, 40, 100, 60, 70, 80, 90].iter().collect();
+    let mut iter = v.into_iter();
+    assert_eq!(iter.try_rfold(0_i8, |acc, &x| acc.checked_add(x)), None);
+    assert_eq!(iter.next_back(), Some(&70));
+}
diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index ba3b3dfbfc2e1..dddfa3f158e71 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -63,18 +63,15 @@ use core::intrinsics::{arith_offset, assume};
 use core::iter::{FromIterator, FusedIterator, TrustedLen};
 use core::marker::PhantomData;
 use core::mem;
+use core::ops::{self, Index, IndexMut, RangeBounds};
 use core::ops::Bound::{Excluded, Included, Unbounded};
-use core::ops::{Index, IndexMut, RangeBounds};
-use core::ops;
-use core::ptr;
-use core::ptr::NonNull;
-use core::slice;
-
-use collections::CollectionAllocErr;
-use borrow::ToOwned;
-use borrow::Cow;
-use boxed::Box;
-use raw_vec::RawVec;
+use core::ptr::{self, NonNull};
+use core::slice::{self, SliceIndex};
+
+use crate::borrow::{ToOwned, Cow};
+use crate::collections::CollectionAllocErr;
+use crate::boxed::Box;
+use crate::raw_vec::RawVec;
 
 /// A contiguous growable array type, written `Vec<T>` but pronounced 'vector'.
 ///
@@ -466,7 +463,7 @@ impl<T> Vec<T> {
     /// Does nothing if the capacity is already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
-    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer `reserve` if future insertions are expected.
     ///
     /// # Panics
@@ -528,7 +525,7 @@ impl<T> Vec<T> {
     /// Does nothing if the capacity is already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
-    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer `reserve` if future insertions are expected.
     ///
     /// # Errors
@@ -741,7 +738,7 @@ impl<T> Vec<T> {
     /// Forces the length of the vector to `new_len`.
     ///
     /// This is a low-level operation that maintains none of the normal
-    /// invariants of the type.  Normally changing the length of a vector
+    /// invariants of the type. Normally changing the length of a vector
     /// is done using one of the safe operations instead, such as
     /// [`truncate`], [`resize`], [`extend`], or [`clear`].
     ///
@@ -1118,7 +1115,7 @@ impl<T> Vec<T> {
     /// assert_eq!(v, &[]);
     /// ```
     #[stable(feature = "drain", since = "1.6.0")]
-    pub fn drain<R>(&mut self, range: R) -> Drain<T>
+    pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>
         where R: RangeBounds<usize>
     {
         // Memory safety
@@ -1368,6 +1365,7 @@ impl<T: Default> Vec<T> {
     /// # Examples
     ///
     /// ```
+    /// # #![allow(deprecated)]
     /// #![feature(vec_resize_default)]
     ///
     /// let mut vec = vec![1, 2, 3];
@@ -1384,6 +1382,9 @@ impl<T: Default> Vec<T> {
     /// [`Default`]: ../../std/default/trait.Default.html
     /// [`Clone`]: ../../std/clone/trait.Clone.html
     #[unstable(feature = "vec_resize_default", issue = "41758")]
+    #[rustc_deprecated(reason = "This is moving towards being removed in favor \
+        of `.resize_with(Default::default)`.  If you disagree, please comment \
+        in the tracking issue.", since = "1.33.0")]
     pub fn resize_default(&mut self, new_len: usize) {
         let len = self.len();
 
@@ -1477,7 +1478,7 @@ impl<'a> SetLenOnDrop<'a> {
     }
 }
 
-impl<'a> Drop for SetLenOnDrop<'a> {
+impl Drop for SetLenOnDrop<'_> {
     #[inline]
     fn drop(&mut self) {
         *self.len = self.local_len;
@@ -1646,7 +1647,7 @@ impl<T: Clone> Clone for Vec<T> {
     // NB see the slice::hack module in slice.rs for more information
     #[cfg(test)]
     fn clone(&self) -> Vec<T> {
-        ::slice::to_vec(&**self)
+        crate::slice::to_vec(&**self)
     }
 
     fn clone_from(&mut self, other: &Vec<T>) {
@@ -1667,10 +1668,7 @@ impl<T: Hash> Hash for Vec<T> {
     message="vector indices are of type `usize` or ranges of `usize`",
     label="vector indices are of type `usize` or ranges of `usize`",
 )]
-impl<T, I> Index<I> for Vec<T>
-where
-    I: ::core::slice::SliceIndex<[T]>,
-{
+impl<T, I: SliceIndex<[T]>> Index<I> for Vec<T> {
     type Output = I::Output;
 
     #[inline]
@@ -1684,10 +1682,7 @@ where
     message="vector indices are of type `usize` or ranges of `usize`",
     label="vector indices are of type `usize` or ranges of `usize`",
 )]
-impl<T, I> IndexMut<I> for Vec<T>
-where
-    I: ::core::slice::SliceIndex<[T]>,
-{
+impl<T, I: SliceIndex<[T]>> IndexMut<I> for Vec<T> {
     #[inline]
     fn index_mut(&mut self, index: I) -> &mut Self::Output {
         IndexMut::index_mut(&mut **self, index)
@@ -1981,7 +1976,7 @@ impl<T> Vec<T> {
     /// ```
     #[inline]
     #[stable(feature = "vec_splice", since = "1.21.0")]
-    pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<I::IntoIter>
+    pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter>
         where R: RangeBounds<usize>, I: IntoIterator<Item=T>
     {
         Splice {
@@ -2036,7 +2031,7 @@ impl<T> Vec<T> {
     /// assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);
     /// ```
     #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-    pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<T, F>
+    pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F>
         where F: FnMut(&mut T) -> bool,
     {
         let old_len = self.len();
@@ -2152,7 +2147,7 @@ impl<T> Default for Vec<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Debug> fmt::Debug for Vec<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&**self, f)
     }
 }
@@ -2193,7 +2188,7 @@ impl<'a, T: Clone> From<&'a [T]> for Vec<T> {
     }
     #[cfg(test)]
     fn from(s: &'a [T]) -> Vec<T> {
-        ::slice::to_vec(s)
+        crate::slice::to_vec(s)
     }
 }
 
@@ -2205,7 +2200,7 @@ impl<'a, T: Clone> From<&'a mut [T]> for Vec<T> {
     }
     #[cfg(test)]
     fn from(s: &'a mut [T]) -> Vec<T> {
-        ::slice::to_vec(s)
+        crate::slice::to_vec(s)
     }
 }
 
@@ -2295,7 +2290,7 @@ pub struct IntoIter<T> {
 
 #[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
 impl<T: fmt::Debug> fmt::Debug for IntoIter<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("IntoIter")
             .field(&self.as_slice())
             .finish()
@@ -2464,8 +2459,8 @@ pub struct Drain<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+impl<T: fmt::Debug> fmt::Debug for Drain<'_, T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Drain")
          .field(&self.iter.as_slice())
          .finish()
@@ -2473,12 +2468,12 @@ impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a, T: Sync> Sync for Drain<'a, T> {}
+unsafe impl<T: Sync> Sync for Drain<'_, T> {}
 #[stable(feature = "drain", since = "1.6.0")]
-unsafe impl<'a, T: Send> Send for Drain<'a, T> {}
+unsafe impl<T: Send> Send for Drain<'_, T> {}
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T> Iterator for Drain<'a, T> {
+impl<T> Iterator for Drain<'_, T> {
     type Item = T;
 
     #[inline]
@@ -2492,7 +2487,7 @@ impl<'a, T> Iterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T> DoubleEndedIterator for Drain<'a, T> {
+impl<T> DoubleEndedIterator for Drain<'_, T> {
     #[inline]
     fn next_back(&mut self) -> Option<T> {
         self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
@@ -2500,7 +2495,7 @@ impl<'a, T> DoubleEndedIterator for Drain<'a, T> {
 }
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T> Drop for Drain<'a, T> {
+impl<T> Drop for Drain<'_, T> {
     fn drop(&mut self) {
         // exhaust self first
         self.for_each(drop);
@@ -2524,14 +2519,14 @@ impl<'a, T> Drop for Drain<'a, T> {
 
 
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, T> ExactSizeIterator for Drain<'a, T> {
+impl<T> ExactSizeIterator for Drain<'_, T> {
     fn is_empty(&self) -> bool {
         self.iter.is_empty()
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T> FusedIterator for Drain<'a, T> {}
+impl<T> FusedIterator for Drain<'_, T> {}
 
 /// A splicing iterator for `Vec`.
 ///
@@ -2548,7 +2543,7 @@ pub struct Splice<'a, I: Iterator + 'a> {
 }
 
 #[stable(feature = "vec_splice", since = "1.21.0")]
-impl<'a, I: Iterator> Iterator for Splice<'a, I> {
+impl<I: Iterator> Iterator for Splice<'_, I> {
     type Item = I::Item;
 
     fn next(&mut self) -> Option<Self::Item> {
@@ -2561,18 +2556,18 @@ impl<'a, I: Iterator> Iterator for Splice<'a, I> {
 }
 
 #[stable(feature = "vec_splice", since = "1.21.0")]
-impl<'a, I: Iterator> DoubleEndedIterator for Splice<'a, I> {
+impl<I: Iterator> DoubleEndedIterator for Splice<'_, I> {
     fn next_back(&mut self) -> Option<Self::Item> {
         self.drain.next_back()
     }
 }
 
 #[stable(feature = "vec_splice", since = "1.21.0")]
-impl<'a, I: Iterator> ExactSizeIterator for Splice<'a, I> {}
+impl<I: Iterator> ExactSizeIterator for Splice<'_, I> {}
 
 
 #[stable(feature = "vec_splice", since = "1.21.0")]
-impl<'a, I: Iterator> Drop for Splice<'a, I> {
+impl<I: Iterator> Drop for Splice<'_, I> {
     fn drop(&mut self) {
         self.drain.by_ref().for_each(drop);
 
@@ -2613,11 +2608,11 @@ impl<'a, I: Iterator> Drop for Splice<'a, I> {
 }
 
 /// Private helper methods for `Splice::drop`
-impl<'a, T> Drain<'a, T> {
+impl<T> Drain<'_, T> {
     /// The range from `self.vec.len` to `self.tail_start` contains elements
     /// that have been moved out.
     /// Fill that range as much as possible with new elements from the `replace_with` iterator.
-    /// Return whether we filled the entire range. (`replace_with.next()` didn’t return `None`.)
+    /// Returns `true` if we filled the entire range. (`replace_with.next()` didn’t return `None`.)
     unsafe fn fill<I: Iterator<Item=T>>(&mut self, replace_with: &mut I) -> bool {
         let vec = self.vec.as_mut();
         let range_start = vec.len;
@@ -2637,7 +2632,7 @@ impl<'a, T> Drain<'a, T> {
         true
     }
 
-    /// Make room for inserting more elements before the tail.
+    /// Makes room for inserting more elements before the tail.
     unsafe fn move_tail(&mut self, extra_capacity: usize) {
         let vec = self.vec.as_mut();
         let used_capacity = self.tail_start + self.tail_len;
@@ -2654,7 +2649,7 @@ impl<'a, T> Drain<'a, T> {
 /// An iterator produced by calling `drain_filter` on Vec.
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
 #[derive(Debug)]
-pub struct DrainFilter<'a, T: 'a, F>
+pub struct DrainFilter<'a, T, F>
     where F: FnMut(&mut T) -> bool,
 {
     vec: &'a mut Vec<T>,
@@ -2665,7 +2660,7 @@ pub struct DrainFilter<'a, T: 'a, F>
 }
 
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<'a, T, F> Iterator for DrainFilter<'a, T, F>
+impl<T, F> Iterator for DrainFilter<'_, T, F>
     where F: FnMut(&mut T) -> bool,
 {
     type Item = T;
@@ -2699,7 +2694,7 @@ impl<'a, T, F> Iterator for DrainFilter<'a, T, F>
 }
 
 #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
-impl<'a, T, F> Drop for DrainFilter<'a, T, F>
+impl<T, F> Drop for DrainFilter<'_, T, F>
     where F: FnMut(&mut T) -> bool,
 {
     fn drop(&mut self) {
diff --git a/src/libarena/Cargo.toml b/src/libarena/Cargo.toml
index e2af67dd92861..82fc64ba64e33 100644
--- a/src/libarena/Cargo.toml
+++ b/src/libarena/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "arena"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "arena"
@@ -9,4 +10,4 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-rustc_data_structures = { path = "../librustc_data_structures" }
\ No newline at end of file
+rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index 9f9ded51e37ee..8ae046c0796bc 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -8,22 +8,20 @@
 //! This crate implements `TypedArena`, a simple arena that can only hold
 //! objects of a single type.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        test(no_crate_inject, attr(deny(warnings))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(alloc)]
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
-#![feature(nll)]
 #![feature(raw_vec_internals)]
 #![cfg_attr(test, feature(test))]
 
 #![allow(deprecated)]
 
 extern crate alloc;
-extern crate rustc_data_structures;
 
 use rustc_data_structures::sync::MTLock;
 
@@ -478,7 +476,7 @@ impl SyncDroplessArena {
 #[cfg(test)]
 mod tests {
     extern crate test;
-    use self::test::Bencher;
+    use test::Bencher;
     use super::TypedArena;
     use std::cell::Cell;
 
@@ -513,15 +511,15 @@ mod tests {
 
         impl<'a> Wrap<'a> {
             fn alloc_inner<F: Fn() -> Inner>(&self, f: F) -> &Inner {
-                let r: &EI = self.0.alloc(EI::I(f()));
+                let r: &EI<'_> = self.0.alloc(EI::I(f()));
                 if let &EI::I(ref i) = r {
                     i
                 } else {
                     panic!("mismatch");
                 }
             }
-            fn alloc_outer<F: Fn() -> Outer<'a>>(&self, f: F) -> &Outer {
-                let r: &EI = self.0.alloc(EI::O(f()));
+            fn alloc_outer<F: Fn() -> Outer<'a>>(&self, f: F) -> &Outer<'_> {
+                let r: &EI<'_> = self.0.alloc(EI::O(f()));
                 if let &EI::O(ref o) = r {
                     o
                 } else {
@@ -611,7 +609,7 @@ mod tests {
         count: &'a Cell<u32>,
     }
 
-    impl<'a> Drop for DropCounter<'a> {
+    impl Drop for DropCounter<'_> {
         fn drop(&mut self) {
             self.count.set(self.count.get() + 1);
         }
@@ -621,7 +619,7 @@ mod tests {
     fn test_typed_arena_drop_count() {
         let counter = Cell::new(0);
         {
-            let arena: TypedArena<DropCounter> = TypedArena::default();
+            let arena: TypedArena<DropCounter<'_>> = TypedArena::default();
             for _ in 0..100 {
                 // Allocate something with drop glue to make sure it doesn't leak.
                 arena.alloc(DropCounter { count: &counter });
@@ -633,7 +631,7 @@ mod tests {
     #[test]
     fn test_typed_arena_drop_on_clear() {
         let counter = Cell::new(0);
-        let mut arena: TypedArena<DropCounter> = TypedArena::default();
+        let mut arena: TypedArena<DropCounter<'_>> = TypedArena::default();
         for i in 0..10 {
             for _ in 0..100 {
                 // Allocate something with drop glue to make sure it doesn't leak.
diff --git a/src/libcore/alloc.rs b/src/libcore/alloc.rs
index 66a3094d77d01..f49e226a5cb68 100644
--- a/src/libcore/alloc.rs
+++ b/src/libcore/alloc.rs
@@ -425,7 +425,7 @@ impl fmt::Display for CannotReallocInPlace {
 /// The `GlobalAlloc` trait is an `unsafe` trait for a number of reasons, and
 /// implementors must ensure that they adhere to these contracts:
 ///
-/// * It's undefined behavior if global allocators unwind.  This restriction may
+/// * It's undefined behavior if global allocators unwind. This restriction may
 ///   be lifted in the future, but currently a panic from any of these
 ///   functions may lead to memory unsafety.
 ///
diff --git a/src/libcore/any.rs b/src/libcore/any.rs
index 6a863ff369a87..01ab523a4c3f6 100644
--- a/src/libcore/any.rs
+++ b/src/libcore/any.rs
@@ -18,7 +18,7 @@
 //!
 //! Consider a situation where we want to log out a value passed to a function.
 //! We know the value we're working on implements Debug, but we don't know its
-//! concrete type.  We want to give special treatment to certain types: in this
+//! concrete type. We want to give special treatment to certain types: in this
 //! case printing out the length of String values prior to their value.
 //! We don't know the concrete type of our value at compile time, so we need to
 //! use runtime reflection instead.
@@ -31,8 +31,8 @@
 //! fn log<T: Any + Debug>(value: &T) {
 //!     let value_any = value as &dyn Any;
 //!
-//!     // try to convert our value to a String.  If successful, we want to
-//!     // output the String's length as well as its value.  If not, it's a
+//!     // Try to convert our value to a `String`. If successful, we want to
+//!     // output the String`'s length as well as its value. If not, it's a
 //!     // different type: just print it out unadorned.
 //!     match value_any.downcast_ref::<String>() {
 //!         Some(as_string) => {
@@ -81,12 +81,10 @@ pub trait Any: 'static {
     /// # Examples
     ///
     /// ```
-    /// #![feature(get_type_id)]
-    ///
     /// use std::any::{Any, TypeId};
     ///
     /// fn is_string(s: &dyn Any) -> bool {
-    ///     TypeId::of::<String>() == s.get_type_id()
+    ///     TypeId::of::<String>() == s.type_id()
     /// }
     ///
     /// fn main() {
@@ -94,15 +92,13 @@ pub trait Any: 'static {
     ///     assert_eq!(is_string(&"cookie monster".to_string()), true);
     /// }
     /// ```
-    #[unstable(feature = "get_type_id",
-               reason = "this method will likely be replaced by an associated static",
-               issue = "27745")]
-    fn get_type_id(&self) -> TypeId;
+    #[stable(feature = "get_type_id", since = "1.34.0")]
+    fn type_id(&self) -> TypeId;
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: 'static + ?Sized > Any for T {
-    fn get_type_id(&self) -> TypeId { TypeId::of::<T>() }
+    fn type_id(&self) -> TypeId { TypeId::of::<T>() }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -161,10 +157,10 @@ impl dyn Any {
         let t = TypeId::of::<T>();
 
         // Get TypeId of the type in the trait object
-        let boxed = self.get_type_id();
+        let concrete = self.type_id();
 
         // Compare both TypeIds on equality
-        t == boxed
+        t == concrete
     }
 
     /// Returns some reference to the boxed value if it is of type `T`, or
diff --git a/src/libcore/benches/fmt.rs b/src/libcore/benches/fmt.rs
new file mode 100644
index 0000000000000..92f10c760c6d2
--- /dev/null
+++ b/src/libcore/benches/fmt.rs
@@ -0,0 +1,110 @@
+use std::io::{self, Write as IoWrite};
+use std::fmt::{self, Write as FmtWrite};
+use test::Bencher;
+
+#[bench]
+fn write_vec_value(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = Vec::new();
+        for _ in 0..1000 {
+            mem.write_all("abc".as_bytes()).unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_vec_ref(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = Vec::new();
+        let wr = &mut mem as &mut dyn io::Write;
+        for _ in 0..1000 {
+            wr.write_all("abc".as_bytes()).unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_vec_macro1(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = Vec::new();
+        let wr = &mut mem as &mut dyn io::Write;
+        for _ in 0..1000 {
+            write!(wr, "abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_vec_macro2(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = Vec::new();
+        let wr = &mut mem as &mut dyn io::Write;
+        for _ in 0..1000 {
+            write!(wr, "{}", "abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_vec_macro_debug(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = Vec::new();
+        let wr = &mut mem as &mut dyn io::Write;
+        for _ in 0..1000 {
+            write!(wr, "{:?}", "☃").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_str_value(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = String::new();
+        for _ in 0..1000 {
+            mem.write_str("abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_str_ref(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = String::new();
+        let wr = &mut mem as &mut dyn fmt::Write;
+        for _ in 0..1000 {
+            wr.write_str("abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_str_macro1(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = String::new();
+        for _ in 0..1000 {
+            write!(mem, "abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_str_macro2(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = String::new();
+        let wr = &mut mem as &mut dyn fmt::Write;
+        for _ in 0..1000 {
+            write!(wr, "{}", "abc").unwrap();
+        }
+    });
+}
+
+#[bench]
+fn write_str_macro_debug(bh: &mut Bencher) {
+    bh.iter(|| {
+        let mut mem = String::new();
+        let wr = &mut mem as &mut dyn fmt::Write;
+        for _ in 0..1000 {
+            write!(wr, "{:?}", "☃").unwrap();
+        }
+    });
+}
diff --git a/src/libcore/benches/lib.rs b/src/libcore/benches/lib.rs
index 5b4971c81dd92..48572af611a5b 100644
--- a/src/libcore/benches/lib.rs
+++ b/src/libcore/benches/lib.rs
@@ -11,3 +11,4 @@ mod iter;
 mod num;
 mod ops;
 mod slice;
+mod fmt;
diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index d57ca13a334e8..8383d305518ab 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -130,7 +130,7 @@
 //!
 //! This is simply a special - but common - case of the previous: hiding mutability for operations
 //! that appear to be immutable. The `clone` method is expected to not change the source value, and
-//! is declared to take `&self`, not `&mut self`. Therefore any mutation that happens in the
+//! is declared to take `&self`, not `&mut self`. Therefore, any mutation that happens in the
 //! `clone` method must use cell types. For example, `Rc<T>` maintains its reference counts within a
 //! `Cell<T>`.
 //!
@@ -1133,7 +1133,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
     /// The `RefCell` is already immutably borrowed, so this cannot fail.
     ///
     /// This is an associated function that needs to be used as
-    /// `Ref::clone(...)`.  A `Clone` implementation or a method would interfere
+    /// `Ref::clone(...)`. A `Clone` implementation or a method would interfere
     /// with the widespread use of `r.borrow().clone()` to clone the contents of
     /// a `RefCell`.
     #[stable(feature = "cell_extras", since = "1.15.0")]
@@ -1145,7 +1145,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
         }
     }
 
-    /// Make a new `Ref` for a component of the borrowed data.
+    /// Makes a new `Ref` for a component of the borrowed data.
     ///
     /// The `RefCell` is already immutably borrowed, so this cannot fail.
     ///
@@ -1174,7 +1174,7 @@ impl<'b, T: ?Sized> Ref<'b, T> {
         }
     }
 
-    /// Split a `Ref` into multiple `Ref`s for different components of the
+    /// Splits a `Ref` into multiple `Ref`s for different components of the
     /// borrowed data.
     ///
     /// The `RefCell` is already immutably borrowed, so this cannot fail.
@@ -1217,13 +1217,13 @@ impl<T: ?Sized + fmt::Display> fmt::Display for Ref<'_, T> {
 }
 
 impl<'b, T: ?Sized> RefMut<'b, T> {
-    /// Make a new `RefMut` for a component of the borrowed data, e.g., an enum
+    /// Makes a new `RefMut` for a component of the borrowed data, e.g., an enum
     /// variant.
     ///
     /// The `RefCell` is already mutably borrowed, so this cannot fail.
     ///
     /// This is an associated function that needs to be used as
-    /// `RefMut::map(...)`.  A method would interfere with methods of the same
+    /// `RefMut::map(...)`. A method would interfere with methods of the same
     /// name on the contents of a `RefCell` used through `Deref`.
     ///
     /// # Examples
@@ -1253,7 +1253,7 @@ impl<'b, T: ?Sized> RefMut<'b, T> {
         }
     }
 
-    /// Split a `RefMut` into multiple `RefMut`s for different components of the
+    /// Splits a `RefMut` into multiple `RefMut`s for different components of the
     /// borrowed data.
     ///
     /// The underlying `RefCell` will remain mutably borrowed until both
@@ -1416,7 +1416,7 @@ impl<T: ?Sized + fmt::Display> fmt::Display for RefMut<'_, T> {
 /// co-exist with it. A `&mut T` must always be unique.
 ///
 /// Note that while mutating or mutably aliasing the contents of an `&UnsafeCell<T>` is
-/// okay (provided you enforce the invariants some other way), it is still undefined behavior
+/// ok (provided you enforce the invariants some other way), it is still undefined behavior
 /// to have multiple `&mut UnsafeCell<T>` aliases.
 ///
 /// # Examples
diff --git a/src/libcore/char/decode.rs b/src/libcore/char/decode.rs
index 510c46cdca0ed..133c9169df858 100644
--- a/src/libcore/char/decode.rs
+++ b/src/libcore/char/decode.rs
@@ -20,7 +20,7 @@ pub struct DecodeUtf16Error {
     code: u16,
 }
 
-/// Create an iterator over the UTF-16 encoded code points in `iter`,
+/// Creates an iterator over the UTF-16 encoded code points in `iter`,
 /// returning unpaired surrogates as `Err`s.
 ///
 /// # Examples
diff --git a/src/libcore/char/methods.rs b/src/libcore/char/methods.rs
index fbc9a4a6b8efa..122e5f3affdc2 100644
--- a/src/libcore/char/methods.rs
+++ b/src/libcore/char/methods.rs
@@ -189,10 +189,8 @@ impl char {
     /// An extended version of `escape_debug` that optionally permits escaping
     /// Extended Grapheme codepoints. This allows us to format characters like
     /// nonspacing marks better when they're at the start of a string.
-    #[doc(hidden)]
-    #[unstable(feature = "str_internals", issue = "0")]
     #[inline]
-    pub fn escape_debug_ext(self, escape_grapheme_extended: bool) -> EscapeDebug {
+    pub(crate) fn escape_debug_ext(self, escape_grapheme_extended: bool) -> EscapeDebug {
         let init_state = match self {
             '\t' => EscapeDefaultState::Backslash('t'),
             '\r' => EscapeDefaultState::Backslash('r'),
@@ -524,7 +522,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is an alphabetic code point, and false if not.
+    /// Returns `true` if this `char` is an alphabetic code point, and false if not.
     ///
     /// # Examples
     ///
@@ -548,7 +546,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` satisfies the 'XID_Start' Unicode property, and false
+    /// Returns `true` if this `char` satisfies the 'XID_Start' Unicode property, and false
     /// otherwise.
     ///
     /// 'XID_Start' is a Unicode Derived Property specified in
@@ -562,7 +560,7 @@ impl char {
         derived_property::XID_Start(self)
     }
 
-    /// Returns true if this `char` satisfies the 'XID_Continue' Unicode property, and false
+    /// Returns `true` if this `char` satisfies the 'XID_Continue' Unicode property, and false
     /// otherwise.
     ///
     /// 'XID_Continue' is a Unicode Derived Property specified in
@@ -576,7 +574,7 @@ impl char {
         derived_property::XID_Continue(self)
     }
 
-    /// Returns true if this `char` is lowercase, and false otherwise.
+    /// Returns `true` if this `char` is lowercase.
     ///
     /// 'Lowercase' is defined according to the terms of the Unicode Derived Core
     /// Property `Lowercase`.
@@ -604,7 +602,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is uppercase, and false otherwise.
+    /// Returns `true` if this `char` is uppercase.
     ///
     /// 'Uppercase' is defined according to the terms of the Unicode Derived Core
     /// Property `Uppercase`.
@@ -632,7 +630,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is whitespace, and false otherwise.
+    /// Returns `true` if this `char` is whitespace.
     ///
     /// 'Whitespace' is defined according to the terms of the Unicode Derived Core
     /// Property `White_Space`.
@@ -659,7 +657,7 @@ impl char {
         }
     }
 
-    /// Returns true if this `char` is alphanumeric, and false otherwise.
+    /// Returns `true` if this `char` is alphanumeric.
     ///
     /// 'Alphanumeric'-ness is defined in terms of the Unicode General Categories
     /// 'Nd', 'Nl', 'No' and the Derived Core Property 'Alphabetic'.
@@ -684,7 +682,7 @@ impl char {
         self.is_alphabetic() || self.is_numeric()
     }
 
-    /// Returns true if this `char` is a control code point, and false otherwise.
+    /// Returns `true` if this `char` is a control code point.
     ///
     /// 'Control code point' is defined in terms of the Unicode General
     /// Category `Cc`.
@@ -704,7 +702,7 @@ impl char {
         general_category::Cc(self)
     }
 
-    /// Returns true if this `char` is an extended grapheme character, and false otherwise.
+    /// Returns `true` if this `char` is an extended grapheme character.
     ///
     /// 'Extended grapheme character' is defined in terms of the Unicode Shaping and Rendering
     /// Category `Grapheme_Extend`.
@@ -713,7 +711,7 @@ impl char {
         derived_property::Grapheme_Extend(self)
     }
 
-    /// Returns true if this `char` is numeric, and false otherwise.
+    /// Returns `true` if this `char` is numeric.
     ///
     /// 'Numeric'-ness is defined in terms of the Unicode General Categories
     /// 'Nd', 'Nl', 'No'.
diff --git a/src/libcore/cmp.rs b/src/libcore/cmp.rs
index 86f28a957cd2c..81fcdeee12d29 100644
--- a/src/libcore/cmp.rs
+++ b/src/libcore/cmp.rs
@@ -26,7 +26,7 @@ use self::Ordering::*;
 /// relations](http://en.wikipedia.org/wiki/Partial_equivalence_relation).
 ///
 /// This trait allows for partial equality, for types that do not have a full
-/// equivalence relation.  For example, in floating point numbers `NaN != NaN`,
+/// equivalence relation. For example, in floating point numbers `NaN != NaN`,
 /// so floating point types implement `PartialEq` but not `Eq`.
 ///
 /// Formally, the equality must be (for all `a`, `b` and `c`):
@@ -91,6 +91,8 @@ use self::Ordering::*;
 /// For example, let's tweak our previous code a bit:
 ///
 /// ```
+/// // The derive implements <BookFormat> == <BookFormat> comparisons
+/// #[derive(PartialEq)]
 /// enum BookFormat {
 ///     Paperback,
 ///     Hardback,
@@ -102,31 +104,34 @@ use self::Ordering::*;
 ///     format: BookFormat,
 /// }
 ///
+/// // Implement <Book> == <BookFormat> comparisons
 /// impl PartialEq<BookFormat> for Book {
 ///     fn eq(&self, other: &BookFormat) -> bool {
-///         match (&self.format, other) {
-///            (BookFormat::Paperback, BookFormat::Paperback) => true,
-///            (BookFormat::Hardback,  BookFormat::Hardback)  => true,
-///            (BookFormat::Ebook,     BookFormat::Ebook)     => true,
-///            (_, _) => false,
-///         }
+///         self.format == *other
+///     }
+/// }
+///
+/// // Implement <BookFormat> == <Book> comparisons
+/// impl PartialEq<Book> for BookFormat {
+///     fn eq(&self, other: &Book) -> bool {
+///         *self == other.format
 ///     }
 /// }
 ///
 /// let b1 = Book { isbn: 3, format: BookFormat::Paperback };
 ///
 /// assert!(b1 == BookFormat::Paperback);
-/// assert!(b1 != BookFormat::Ebook);
+/// assert!(BookFormat::Ebook != b1);
 /// ```
 ///
 /// By changing `impl PartialEq for Book` to `impl PartialEq<BookFormat> for Book`,
-/// we've changed what type we can use on the right side of the `==` operator.
-/// This lets us use it in the `assert!` statements at the bottom.
+/// we allow `BookFormat`s to be compared with `Book`s.
 ///
 /// You can also combine these implementations to let the `==` operator work with
 /// two different types:
 ///
 /// ```
+/// #[derive(PartialEq)]
 /// enum BookFormat {
 ///     Paperback,
 ///     Hardback,
@@ -140,12 +145,13 @@ use self::Ordering::*;
 ///
 /// impl PartialEq<BookFormat> for Book {
 ///     fn eq(&self, other: &BookFormat) -> bool {
-///         match (&self.format, other) {
-///            (&BookFormat::Paperback, &BookFormat::Paperback) => true,
-///            (&BookFormat::Hardback,  &BookFormat::Hardback)  => true,
-///            (&BookFormat::Ebook,     &BookFormat::Ebook)     => true,
-///            (_, _) => false,
-///         }
+///         self.format == *other
+///     }
+/// }
+///
+/// impl PartialEq<Book> for BookFormat {
+///     fn eq(&self, other: &Book) -> bool {
+///         *self == other.format
 ///     }
 /// }
 ///
@@ -159,7 +165,7 @@ use self::Ordering::*;
 /// let b2 = Book { isbn: 3, format: BookFormat::Ebook };
 ///
 /// assert!(b1 == BookFormat::Paperback);
-/// assert!(b1 != BookFormat::Ebook);
+/// assert!(BookFormat::Ebook != b1);
 /// assert!(b1 == b2);
 /// ```
 ///
diff --git a/src/libcore/convert.rs b/src/libcore/convert.rs
index 08b5ac06f72de..b8d751cfbb6df 100644
--- a/src/libcore/convert.rs
+++ b/src/libcore/convert.rs
@@ -17,7 +17,10 @@
 //! [`TryFrom<T>`][`TryFrom`] rather than [`Into<U>`][`Into`] or [`TryInto<U>`][`TryInto`],
 //! as [`From`] and [`TryFrom`] provide greater flexibility and offer
 //! equivalent [`Into`] or [`TryInto`] implementations for free, thanks to a
-//! blanket implementation in the standard library.
+//! blanket implementation in the standard library.  However, there are some cases
+//! where this is not possible, such as creating conversions into a type defined
+//! outside your library, so implementing [`Into`] instead of [`From`] is
+//! sometimes necessary.
 //!
 //! # Generic Implementations
 //!
@@ -113,9 +116,6 @@ pub const fn identity<T>(x: T) -> T { x }
 /// - Use `Borrow` when the goal is related to writing code that is agnostic to
 ///   the type of borrow and whether it is a reference or value
 ///
-/// See [the book][book] for a more detailed comparison.
-///
-/// [book]: ../../book/first-edition/borrow-and-asref.html
 /// [`Borrow`]: ../../std/borrow/trait.Borrow.html
 ///
 /// **Note: this trait must not fail**. If the conversion can fail, use a
@@ -217,7 +217,7 @@ pub trait AsMut<T: ?Sized> {
 ///
 /// There is one exception to implementing `Into`, and it's kind of esoteric.
 /// If the destination type is not part of the current crate, and it uses a
-/// generic variable, then you can't implement `From` directly.  For example,
+/// generic variable, then you can't implement `From` directly. For example,
 /// take this crate:
 ///
 /// ```compile_fail
@@ -348,7 +348,7 @@ pub trait Into<T>: Sized {
 /// [`String`]: ../../std/string/struct.String.html
 /// [`Into<U>`]: trait.Into.html
 /// [`from`]: trait.From.html#tymethod.from
-/// [book]: ../../book/first-edition/error-handling.html
+/// [book]: ../../book/ch09-00-error-handling.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait From<T>: Sized {
     /// Performs the conversion.
@@ -463,11 +463,11 @@ impl<T, U> TryInto<U> for T where U: TryFrom<T>
 // Infallible conversions are semantically equivalent to fallible conversions
 // with an uninhabited error type.
 #[unstable(feature = "try_from", issue = "33417")]
-impl<T, U> TryFrom<U> for T where T: From<U> {
+impl<T, U> TryFrom<U> for T where U: Into<T> {
     type Error = !;
 
     fn try_from(value: U) -> Result<Self, Self::Error> {
-        Ok(T::from(value))
+        Ok(U::into(value))
     }
 }
 
diff --git a/src/libcore/default.rs b/src/libcore/default.rs
index 0e47c2fd0b5d0..5ad05b3824764 100644
--- a/src/libcore/default.rs
+++ b/src/libcore/default.rs
@@ -54,7 +54,7 @@
 ///
 /// ## How can I implement `Default`?
 ///
-/// Provide an implementation for the `default()` method that returns the value of
+/// Provides an implementation for the `default()` method that returns the value of
 /// your type that should be the default:
 ///
 /// ```
diff --git a/src/libcore/ffi.rs b/src/libcore/ffi.rs
index 0717a88b6b8f3..d88793f2801e7 100644
--- a/src/libcore/ffi.rs
+++ b/src/libcore/ffi.rs
@@ -12,24 +12,27 @@ use ::fmt;
 /// and `*mut c_void` is equivalent to C's `void*`. That said, this is
 /// *not* the same as C's `void` return type, which is Rust's `()` type.
 ///
-/// Ideally, this type would be equivalent to [`!`], but currently it may
-/// be more ideal to use `c_void` for FFI purposes.
+/// To model pointers to opaque types in FFI, until `extern type` is
+/// stabilized, it is recommended to use a newtype wrapper around an empty
+/// byte array. See the [Nomicon] for details.
 ///
-/// [`!`]: ../../std/primitive.never.html
 /// [pointer]: ../../std/primitive.pointer.html
+/// [Nomicon]: https://doc.rust-lang.org/nomicon/ffi.html#representing-opaque-structs
 // N.B., for LLVM to recognize the void pointer type and by extension
 //     functions like malloc(), we need to have it represented as i8* in
 //     LLVM bitcode. The enum used here ensures this and prevents misuse
-//     of the "raw" type by only having private variants.. We need two
+//     of the "raw" type by only having private variants. We need two
 //     variants, because the compiler complains about the repr attribute
-//     otherwise.
+//     otherwise and we need at least one variant as otherwise the enum
+//     would be uninhabited and at least dereferencing such pointers would
+//     be UB.
 #[repr(u8)]
 #[stable(feature = "raw_os", since = "1.1.0")]
 pub enum c_void {
-    #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+    #[unstable(feature = "c_void_variant", reason = "temporary implementation detail",
                issue = "0")]
     #[doc(hidden)] __variant1,
-    #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+    #[unstable(feature = "c_void_variant", reason = "temporary implementation detail",
                issue = "0")]
     #[doc(hidden)] __variant2,
 }
@@ -49,7 +52,7 @@ impl fmt::Debug for c_void {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 extern {
     type VaListImpl;
 }
@@ -74,7 +77,7 @@ impl fmt::Debug for VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     stack: *mut (),
     gr_top: *mut (),
@@ -90,7 +93,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     gpr: u8,
     fpr: u8,
@@ -106,7 +109,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 struct VaListImpl {
     gp_offset: i32,
     fp_offset: i32,
@@ -120,7 +123,7 @@ struct VaListImpl {
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 #[repr(transparent)]
 pub struct VaList<'a>(&'a mut VaListImpl);
 
@@ -140,7 +143,7 @@ mod sealed_trait {
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub trait VaArgSafe {}
 }
 
@@ -150,7 +153,7 @@ macro_rules! impl_va_arg_safe {
             #[unstable(feature = "c_variadic",
                        reason = "the `c_variadic` feature has not been properly tested on \
                                  all supported platforms",
-                       issue = "27745")]
+                       issue = "44930")]
             impl sealed_trait::VaArgSafe for $t {}
         )+
     }
@@ -163,12 +166,12 @@ impl_va_arg_safe!{f64}
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 impl<T> sealed_trait::VaArgSafe for *mut T {}
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 impl<T> sealed_trait::VaArgSafe for *const T {}
 
 impl<'a> VaList<'a> {
@@ -176,16 +179,16 @@ impl<'a> VaList<'a> {
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub unsafe fn arg<T: sealed_trait::VaArgSafe>(&mut self) -> T {
         va_arg(self)
     }
 
-    /// Copy the `va_list` at the current location.
+    /// Copies the `va_list` at the current location.
     #[unstable(feature = "c_variadic",
                reason = "the `c_variadic` feature has not been properly tested on \
                          all supported platforms",
-               issue = "27745")]
+               issue = "44930")]
     pub unsafe fn copy<F, R>(&self, f: F) -> R
             where F: for<'copy> FnOnce(VaList<'copy>) -> R {
         #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
@@ -210,7 +213,7 @@ extern "rust-intrinsic" {
     /// `va_copy`.
     fn va_end(ap: &mut VaList);
 
-    /// Copy the current location of arglist `src` to the arglist `dst`.
+    /// Copies the current location of arglist `src` to the arglist `dst`.
     #[cfg(any(all(not(target_arch = "aarch64"), not(target_arch = "powerpc"),
                   not(target_arch = "x86_64")),
               windows))]
diff --git a/src/libcore/fmt/builders.rs b/src/libcore/fmt/builders.rs
index 2525b47f2bde5..45994c2b4f0f0 100644
--- a/src/libcore/fmt/builders.rs
+++ b/src/libcore/fmt/builders.rs
@@ -71,8 +71,10 @@ impl fmt::Write for PadAdapter<'_> {
 ///     }
 /// }
 ///
-/// // prints "Foo { bar: 10, baz: "Hello World" }"
-/// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() });
+/// assert_eq!(
+///     format!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() }),
+///     "Foo { bar: 10, baz: \"Hello World\" }",
+/// );
 /// ```
 #[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
@@ -96,6 +98,33 @@ pub fn debug_struct_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>,
 
 impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
     /// Adds a new field to the generated struct output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Bar {
+    ///     bar: i32,
+    ///     another: String,
+    /// }
+    ///
+    /// impl fmt::Debug for Bar {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_struct("Bar")
+    ///            .field("bar", &self.bar) // We add `bar` field.
+    ///            .field("another", &self.another) // We add `another` field.
+    ///            // We even add a field which doesn't exist (because why not?).
+    ///            .field("not_existing_field", &1)
+    ///            .finish() // We're good to go!
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Bar { bar: 10, another: "Hello World".to_string() }),
+    ///     "Bar { bar: 10, another: \"Hello World\", not_existing_field: 1 }",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn field(&mut self, name: &str, value: &dyn fmt::Debug) -> &mut DebugStruct<'a, 'b> {
         self.result = self.result.and_then(|_| {
@@ -124,6 +153,32 @@ impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
     }
 
     /// Finishes output and returns any error encountered.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Bar {
+    ///     bar: i32,
+    ///     baz: String,
+    /// }
+    ///
+    /// impl fmt::Debug for Bar {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_struct("Bar")
+    ///            .field("bar", &self.bar)
+    ///            .field("baz", &self.baz)
+    ///            .finish() // You need to call it to "finish" the
+    ///                      // struct formatting.
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Bar { bar: 10, baz: "Hello World".to_string() }),
+    ///     "Bar { bar: 10, baz: \"Hello World\" }",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
         if self.has_fields {
@@ -168,8 +223,10 @@ impl<'a, 'b: 'a> DebugStruct<'a, 'b> {
 ///     }
 /// }
 ///
-/// // prints "Foo(10, "Hello World")"
-/// println!("{:?}", Foo(10, "Hello World".to_string()));
+/// assert_eq!(
+///     format!("{:?}", Foo(10, "Hello World".to_string())),
+///     "Foo(10, \"Hello World\")",
+/// );
 /// ```
 #[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
@@ -193,6 +250,28 @@ pub fn debug_tuple_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>, name: &str) -> D
 
 impl<'a, 'b: 'a> DebugTuple<'a, 'b> {
     /// Adds a new field to the generated tuple struct output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32, String);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_tuple("Foo")
+    ///            .field(&self.0) // We add the first field.
+    ///            .field(&self.1) // We add the second field.
+    ///            .finish() // We're good to go!
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(10, "Hello World".to_string())),
+    ///     "Foo(10, \"Hello World\")",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn field(&mut self, value: &dyn fmt::Debug) -> &mut DebugTuple<'a, 'b> {
         self.result = self.result.and_then(|_| {
@@ -220,6 +299,29 @@ impl<'a, 'b: 'a> DebugTuple<'a, 'b> {
     }
 
     /// Finishes output and returns any error encountered.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(i32, String);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_tuple("Foo")
+    ///            .field(&self.0)
+    ///            .field(&self.1)
+    ///            .finish() // You need to call it to "finish" the
+    ///                      // tuple formatting.
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(10, "Hello World".to_string())),
+    ///     "Foo(10, \"Hello World\")",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
         if self.fields > 0 {
@@ -306,8 +408,10 @@ impl<'a, 'b: 'a> DebugInner<'a, 'b> {
 ///     }
 /// }
 ///
-/// // prints "{10, 11}"
-/// println!("{:?}", Foo(vec![10, 11]));
+/// assert_eq!(
+///     format!("{:?}", Foo(vec![10, 11])),
+///     "{10, 11}",
+/// );
 /// ```
 #[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
@@ -329,6 +433,28 @@ pub fn debug_set_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugSet<'a, 'b
 
 impl<'a, 'b: 'a> DebugSet<'a, 'b> {
     /// Adds a new entry to the set output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>, Vec<u32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_set()
+    ///            .entry(&self.0) // Adds the first "entry".
+    ///            .entry(&self.1) // Adds the second "entry".
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
+    ///     "{[10, 11], [12, 13]}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entry(&mut self, entry: &dyn fmt::Debug) -> &mut DebugSet<'a, 'b> {
         self.inner.entry(entry);
@@ -336,6 +462,28 @@ impl<'a, 'b: 'a> DebugSet<'a, 'b> {
     }
 
     /// Adds the contents of an iterator of entries to the set output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>, Vec<u32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_set()
+    ///            .entries(self.0.iter()) // Adds the first "entry".
+    ///            .entries(self.1.iter()) // Adds the second "entry".
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
+    ///     "{10, 11, 12, 13}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugSet<'a, 'b>
         where D: fmt::Debug,
@@ -348,6 +496,27 @@ impl<'a, 'b: 'a> DebugSet<'a, 'b> {
     }
 
     /// Finishes output and returns any error encountered.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_set()
+    ///            .entries(self.0.iter())
+    ///            .finish() // Ends the struct formatting.
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11])),
+    ///     "{10, 11}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
         self.inner.finish();
@@ -377,8 +546,10 @@ impl<'a, 'b: 'a> DebugSet<'a, 'b> {
 ///     }
 /// }
 ///
-/// // prints "[10, 11]"
-/// println!("{:?}", Foo(vec![10, 11]));
+/// assert_eq!(
+///     format!("{:?}", Foo(vec![10, 11])),
+///     "[10, 11]",
+/// );
 /// ```
 #[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
@@ -400,6 +571,28 @@ pub fn debug_list_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugList<'a,
 
 impl<'a, 'b: 'a> DebugList<'a, 'b> {
     /// Adds a new entry to the list output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>, Vec<u32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_list()
+    ///            .entry(&self.0) // We add the first "entry".
+    ///            .entry(&self.1) // We add the second "entry".
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
+    ///     "[[10, 11], [12, 13]]",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entry(&mut self, entry: &dyn fmt::Debug) -> &mut DebugList<'a, 'b> {
         self.inner.entry(entry);
@@ -407,6 +600,28 @@ impl<'a, 'b: 'a> DebugList<'a, 'b> {
     }
 
     /// Adds the contents of an iterator of entries to the list output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>, Vec<u32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_list()
+    ///            .entries(self.0.iter())
+    ///            .entries(self.1.iter())
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
+    ///     "[10, 11, 12, 13]",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugList<'a, 'b>
         where D: fmt::Debug,
@@ -419,6 +634,27 @@ impl<'a, 'b: 'a> DebugList<'a, 'b> {
     }
 
     /// Finishes output and returns any error encountered.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<i32>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_list()
+    ///            .entries(self.0.iter())
+    ///            .finish() // Ends the struct formatting.
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![10, 11])),
+    ///     "[10, 11]",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
         self.inner.finish();
@@ -448,8 +684,10 @@ impl<'a, 'b: 'a> DebugList<'a, 'b> {
 ///     }
 /// }
 ///
-/// // prints "{"A": 10, "B": 11}"
-/// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)]));
+/// assert_eq!(
+///     format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
+///     "{\"A\": 10, \"B\": 11}",
+/// );
 /// ```
 #[must_use = "must eventually call `finish()` on Debug builders"]
 #[allow(missing_debug_implementations)]
@@ -471,6 +709,27 @@ pub fn debug_map_new<'a, 'b>(fmt: &'a mut fmt::Formatter<'b>) -> DebugMap<'a, 'b
 
 impl<'a, 'b: 'a> DebugMap<'a, 'b> {
     /// Adds a new entry to the map output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<(String, i32)>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_map()
+    ///            .entry(&"whole", &self.0) // We add the "whole" entry.
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
+    ///     "{\"whole\": [(\"A\", 10), (\"B\", 11)]}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entry(&mut self, key: &dyn fmt::Debug, value: &dyn fmt::Debug) -> &mut DebugMap<'a, 'b> {
         self.result = self.result.and_then(|_| {
@@ -500,6 +759,29 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
     }
 
     /// Adds the contents of an iterator of entries to the map output.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<(String, i32)>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_map()
+    ///            // We map our vec so each entries' first field will become
+    ///            // the "key".
+    ///            .entries(self.0.iter().map(|&(ref k, ref v)| (k, v)))
+    ///            .finish()
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
+    ///     "{\"A\": 10, \"B\": 11}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn entries<K, V, I>(&mut self, entries: I) -> &mut DebugMap<'a, 'b>
         where K: fmt::Debug,
@@ -513,6 +795,27 @@ impl<'a, 'b: 'a> DebugMap<'a, 'b> {
     }
 
     /// Finishes output and returns any error encountered.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::fmt;
+    ///
+    /// struct Foo(Vec<(String, i32)>);
+    ///
+    /// impl fmt::Debug for Foo {
+    ///     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    ///         fmt.debug_map()
+    ///            .entries(self.0.iter().map(|&(ref k, ref v)| (k, v)))
+    ///            .finish() // Ends the struct formatting.
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(
+    ///     format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
+    ///     "{\"A\": 10, \"B\": 11}",
+    /// );
+    /// ```
     #[stable(feature = "debug_builders", since = "1.2.0")]
     pub fn finish(&mut self) -> fmt::Result {
         let prefix = if self.is_pretty() && self.has_fields {
diff --git a/src/libcore/fmt/mod.rs b/src/libcore/fmt/mod.rs
index 214b5d3a84f24..7efb7f31298bf 100644
--- a/src/libcore/fmt/mod.rs
+++ b/src/libcore/fmt/mod.rs
@@ -211,9 +211,18 @@ impl<W: Write + ?Sized> Write for &mut W {
     }
 }
 
-/// A struct to represent both where to emit formatting strings to and how they
-/// should be formatted. A mutable version of this is passed to all formatting
-/// traits.
+/// Configuration for formatting.
+///
+/// A `Formatter` represents various options related to formatting. Users do not
+/// construct `Formatter`s directly; a mutable reference to one is passed to
+/// the `fmt` method of all formatting traits, like [`Debug`] and [`Display`].
+///
+/// To interact with a `Formatter`, you'll call various methods to change the
+/// various options related to formatting. For examples, please see the
+/// documentation of the methods defined on `Formatter` below.
+///
+/// [`Debug`]: trait.Debug.html
+/// [`Display`]: trait.Display.html
 #[allow(missing_debug_implementations)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Formatter<'a> {
@@ -474,12 +483,12 @@ impl Display for Arguments<'_> {
 /// implementations, such as [`debug_struct`][debug_struct].
 ///
 /// `Debug` implementations using either `derive` or the debug builder API
-/// on [`Formatter`] support pretty printing using the alternate flag: `{:#?}`.
+/// on [`Formatter`] support pretty-printing using the alternate flag: `{:#?}`.
 ///
 /// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct
 /// [`Formatter`]: ../../std/fmt/struct.Formatter.html
 ///
-/// Pretty printing with `#?`:
+/// Pretty-printing with `#?`:
 ///
 /// ```
 /// #[derive(Debug)]
@@ -997,34 +1006,57 @@ pub fn write(output: &mut dyn Write, args: Arguments) -> Result {
         curarg: args.args.iter(),
     };
 
-    let mut pieces = args.pieces.iter();
+    let mut idx = 0;
 
     match args.fmt {
         None => {
             // We can use default formatting parameters for all arguments.
-            for (arg, piece) in args.args.iter().zip(pieces.by_ref()) {
+            for (arg, piece) in args.args.iter().zip(args.pieces.iter()) {
                 formatter.buf.write_str(*piece)?;
                 (arg.formatter)(arg.value, &mut formatter)?;
+                idx += 1;
             }
         }
         Some(fmt) => {
             // Every spec has a corresponding argument that is preceded by
             // a string piece.
-            for (arg, piece) in fmt.iter().zip(pieces.by_ref()) {
+            for (arg, piece) in fmt.iter().zip(args.pieces.iter()) {
                 formatter.buf.write_str(*piece)?;
                 formatter.run(arg)?;
+                idx += 1;
             }
         }
     }
 
     // There can be only one trailing string piece left.
-    if let Some(piece) = pieces.next() {
+    if let Some(piece) = args.pieces.get(idx) {
         formatter.buf.write_str(*piece)?;
     }
 
     Ok(())
 }
 
+/// Padding after the end of something. Returned by `Formatter::padding`.
+#[must_use = "don't forget to write the post padding"]
+struct PostPadding {
+    fill: char,
+    padding: usize,
+}
+
+impl PostPadding {
+    fn new(fill: char, padding: usize) -> PostPadding {
+        PostPadding { fill, padding }
+    }
+
+    /// Write this post padding.
+    fn write(self, buf: &mut dyn Write) -> Result {
+        for _ in 0..self.padding {
+            buf.write_char(self.fill)?;
+        }
+        Ok(())
+    }
+}
+
 impl<'a> Formatter<'a> {
     fn wrap_buf<'b, 'c, F>(&'b mut self, wrap: F) -> Formatter<'c>
         where 'b: 'c, F: FnOnce(&'b mut (dyn Write+'b)) -> &'c mut (dyn Write+'c)
@@ -1142,47 +1174,56 @@ impl<'a> Formatter<'a> {
             sign = Some('+'); width += 1;
         }
 
-        let prefixed = self.alternate();
-        if prefixed {
+        let prefix = if self.alternate() {
             width += prefix.chars().count();
-        }
+            Some(prefix)
+        } else {
+            None
+        };
 
         // Writes the sign if it exists, and then the prefix if it was requested
-        let write_prefix = |f: &mut Formatter| {
+        #[inline(never)]
+        fn write_prefix(f: &mut Formatter, sign: Option<char>, prefix: Option<&str>) -> Result {
             if let Some(c) = sign {
                 f.buf.write_char(c)?;
             }
-            if prefixed { f.buf.write_str(prefix) }
-            else { Ok(()) }
-        };
+            if let Some(prefix) = prefix {
+                f.buf.write_str(prefix)
+            } else {
+                Ok(())
+            }
+        }
 
         // The `width` field is more of a `min-width` parameter at this point.
         match self.width {
             // If there's no minimum length requirements then we can just
             // write the bytes.
             None => {
-                write_prefix(self)?; self.buf.write_str(buf)
+                write_prefix(self, sign, prefix)?;
+                self.buf.write_str(buf)
             }
             // Check if we're over the minimum width, if so then we can also
             // just write the bytes.
             Some(min) if width >= min => {
-                write_prefix(self)?; self.buf.write_str(buf)
+                write_prefix(self, sign, prefix)?;
+                self.buf.write_str(buf)
             }
             // The sign and prefix goes before the padding if the fill character
             // is zero
             Some(min) if self.sign_aware_zero_pad() => {
                 self.fill = '0';
                 self.align = rt::v1::Alignment::Right;
-                write_prefix(self)?;
-                self.with_padding(min - width, rt::v1::Alignment::Right, |f| {
-                    f.buf.write_str(buf)
-                })
+                write_prefix(self, sign, prefix)?;
+                let post_padding = self.padding(min - width, rt::v1::Alignment::Right)?;
+                self.buf.write_str(buf)?;
+                post_padding.write(self.buf)
             }
             // Otherwise, the sign and prefix goes after the padding
             Some(min) => {
-                self.with_padding(min - width, rt::v1::Alignment::Right, |f| {
-                    write_prefix(f)?; f.buf.write_str(buf)
-                })
+                let post_padding = self.padding(min - width, rt::v1::Alignment::Right)?;
+                write_prefix(self, sign, prefix)?;
+                self.buf.write_str(buf)?;
+                post_padding.write(self.buf)
             }
         }
     }
@@ -1253,19 +1294,21 @@ impl<'a> Formatter<'a> {
             // up the minimum width with the specified string + some alignment.
             Some(width) => {
                 let align = rt::v1::Alignment::Left;
-                self.with_padding(width - s.chars().count(), align, |me| {
-                    me.buf.write_str(s)
-                })
+                let post_padding = self.padding(width - s.chars().count(), align)?;
+                self.buf.write_str(s)?;
+                post_padding.write(self.buf)
             }
         }
     }
 
-    /// Runs a callback, emitting the correct padding either before or
-    /// afterwards depending on whether right or left alignment is requested.
-    fn with_padding<F>(&mut self, padding: usize, default: rt::v1::Alignment,
-                       f: F) -> Result
-        where F: FnOnce(&mut Formatter) -> Result,
-    {
+    /// Write the pre-padding and return the unwritten post-padding. Callers are
+    /// responsible for ensuring post-padding is written after the thing that is
+    /// being padded.
+    fn padding(
+        &mut self,
+        padding: usize,
+        default: rt::v1::Alignment
+    ) -> result::Result<PostPadding, Error> {
         let align = match self.align {
             rt::v1::Alignment::Unknown => default,
             _ => self.align
@@ -1278,20 +1321,11 @@ impl<'a> Formatter<'a> {
             rt::v1::Alignment::Center => (padding / 2, (padding + 1) / 2),
         };
 
-        let mut fill = [0; 4];
-        let fill = self.fill.encode_utf8(&mut fill);
-
         for _ in 0..pre_pad {
-            self.buf.write_str(fill)?;
-        }
-
-        f(self)?;
-
-        for _ in 0..post_pad {
-            self.buf.write_str(fill)?;
+            self.buf.write_char(self.fill)?;
         }
 
-        Ok(())
+        Ok(PostPadding::new(self.fill, post_pad))
     }
 
     /// Takes the formatted parts and applies the padding.
@@ -1323,9 +1357,9 @@ impl<'a> Formatter<'a> {
             let ret = if width <= len { // no padding
                 self.write_formatted_parts(&formatted)
             } else {
-                self.with_padding(width - len, align, |f| {
-                    f.write_formatted_parts(&formatted)
-                })
+                let post_padding = self.padding(width - len, align)?;
+                self.write_formatted_parts(&formatted)?;
+                post_padding.write(self.buf)
             };
             self.fill = old_fill;
             self.align = old_align;
@@ -2037,7 +2071,7 @@ macro_rules! tuple {
     ( $($name:ident,)+ ) => (
         #[stable(feature = "rust1", since = "1.0.0")]
         impl<$($name:Debug),*> Debug for ($($name,)*) where last_type!($($name,)+): ?Sized {
-            #[allow(non_snake_case, unused_assignments, deprecated)]
+            #[allow(non_snake_case, unused_assignments)]
             fn fmt(&self, f: &mut Formatter) -> Result {
                 let mut builder = f.debug_tuple("");
                 let ($(ref $name,)*) = *self;
diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs
index c7c8fc50efaae..b9fa364037108 100644
--- a/src/libcore/fmt/num.rs
+++ b/src/libcore/fmt/num.rs
@@ -1,14 +1,12 @@
 //! Integer and floating-point number formatting
 
-#![allow(deprecated)]
-
 
 use fmt;
 use ops::{Div, Rem, Sub};
 use str;
 use slice;
 use ptr;
-use mem;
+use mem::MaybeUninit;
 
 #[doc(hidden)]
 trait Int: PartialEq + PartialOrd + Div<Output=Self> + Rem<Output=Self> +
@@ -53,7 +51,7 @@ trait GenericRadix {
         // characters for a base 2 number.
         let zero = T::zero();
         let is_nonnegative = x >= zero;
-        let mut buf: [u8; 128] = unsafe { mem::uninitialized() };
+        let mut buf = uninitialized_array![u8; 128];
         let mut curr = buf.len();
         let base = T::from_u8(Self::BASE);
         if is_nonnegative {
@@ -62,7 +60,7 @@ trait GenericRadix {
             for byte in buf.iter_mut().rev() {
                 let n = x % base;               // Get the current place value.
                 x = x / base;                   // Deaccumulate the number.
-                *byte = Self::digit(n.to_u8()); // Store the digit in the buffer.
+                byte.set(Self::digit(n.to_u8())); // Store the digit in the buffer.
                 curr -= 1;
                 if x == zero {
                     // No more digits left to accumulate.
@@ -74,7 +72,7 @@ trait GenericRadix {
             for byte in buf.iter_mut().rev() {
                 let n = zero - (x % base);      // Get the current place value.
                 x = x / base;                   // Deaccumulate the number.
-                *byte = Self::digit(n.to_u8()); // Store the digit in the buffer.
+                byte.set(Self::digit(n.to_u8())); // Store the digit in the buffer.
                 curr -= 1;
                 if x == zero {
                     // No more digits left to accumulate.
@@ -82,7 +80,11 @@ trait GenericRadix {
                 };
             }
         }
-        let buf = unsafe { str::from_utf8_unchecked(&buf[curr..]) };
+        let buf = &buf[curr..];
+        let buf = unsafe { str::from_utf8_unchecked(slice::from_raw_parts(
+            MaybeUninit::first_ptr(buf),
+            buf.len()
+        )) };
         f.pad_integral(is_nonnegative, Self::PREFIX, buf)
     }
 }
@@ -176,7 +178,8 @@ integer! { i32, u32 }
 integer! { i64, u64 }
 integer! { i128, u128 }
 
-const DEC_DIGITS_LUT: &'static[u8] =
+
+static DEC_DIGITS_LUT: &[u8; 200] =
     b"0001020304050607080910111213141516171819\
       2021222324252627282930313233343536373839\
       4041424344454647484950515253545556575859\
@@ -184,37 +187,27 @@ const DEC_DIGITS_LUT: &'static[u8] =
       8081828384858687888990919293949596979899";
 
 macro_rules! impl_Display {
-    ($($t:ident),*: $conv_fn:ident) => ($(
-    #[stable(feature = "rust1", since = "1.0.0")]
-    impl fmt::Display for $t {
-        #[allow(unused_comparisons)]
-        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-            let is_nonnegative = *self >= 0;
-            let mut n = if is_nonnegative {
-                self.$conv_fn()
-            } else {
-                // convert the negative num to positive by summing 1 to it's 2 complement
-                (!self.$conv_fn()).wrapping_add(1)
-            };
-            let mut buf: [u8; 39] = unsafe { mem::uninitialized() };
+    ($($t:ident),* as $u:ident via $conv_fn:ident named $name:ident) => {
+        fn $name(mut n: $u, is_nonnegative: bool, f: &mut fmt::Formatter) -> fmt::Result {
+            let mut buf = uninitialized_array![u8; 39];
             let mut curr = buf.len() as isize;
-            let buf_ptr = buf.as_mut_ptr();
+            let buf_ptr = MaybeUninit::first_ptr_mut(&mut buf);
             let lut_ptr = DEC_DIGITS_LUT.as_ptr();
 
             unsafe {
                 // need at least 16 bits for the 4-characters-at-a-time to work.
-                if ::mem::size_of::<$t>() >= 2 {
-                    // eagerly decode 4 characters at a time
-                    while n >= 10000 {
-                        let rem = (n % 10000) as isize;
-                        n /= 10000;
-
-                        let d1 = (rem / 100) << 1;
-                        let d2 = (rem % 100) << 1;
-                        curr -= 4;
-                        ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
-                        ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
-                    }
+                assert!(::mem::size_of::<$u>() >= 2);
+
+                // eagerly decode 4 characters at a time
+                while n >= 10000 {
+                    let rem = (n % 10000) as isize;
+                    n /= 10000;
+
+                    let d1 = (rem / 100) << 1;
+                    let d2 = (rem % 100) << 1;
+                    curr -= 4;
+                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
+                    ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
                 }
 
                 // if we reach here numbers are <= 9999, so at most 4 chars long
@@ -245,15 +238,41 @@ macro_rules! impl_Display {
             };
             f.pad_integral(is_nonnegative, "", buf_slice)
         }
-    })*);
+
+        $(
+            #[stable(feature = "rust1", since = "1.0.0")]
+            impl fmt::Display for $t {
+                #[allow(unused_comparisons)]
+                fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                    let is_nonnegative = *self >= 0;
+                    let n = if is_nonnegative {
+                        self.$conv_fn()
+                    } else {
+                        // convert the negative num to positive by summing 1 to it's 2 complement
+                        (!self.$conv_fn()).wrapping_add(1)
+                    };
+                    $name(n, is_nonnegative, f)
+                }
+            })*
+    };
+}
+
+// Include wasm32 in here since it doesn't reflect the native pointer size, and
+// often cares strongly about getting a smaller code size.
+#[cfg(any(target_pointer_width = "64", target_arch = "wasm32"))]
+mod imp {
+    use super::*;
+    impl_Display!(
+        i8, u8, i16, u16, i32, u32, i64, u64, usize, isize
+            as u64 via to_u64 named fmt_u64
+    );
+}
+
+#[cfg(not(any(target_pointer_width = "64", target_arch = "wasm32")))]
+mod imp {
+    use super::*;
+    impl_Display!(i8, u8, i16, u16, i32, u32, isize, usize as u32 via to_u32 named fmt_u32);
+    impl_Display!(i64, u64 as u64 via to_u64 named fmt_u64);
 }
 
-impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
-impl_Display!(i64, u64: to_u64);
-impl_Display!(i128, u128: to_u128);
-#[cfg(target_pointer_width = "16")]
-impl_Display!(isize, usize: to_u16);
-#[cfg(target_pointer_width = "32")]
-impl_Display!(isize, usize: to_u32);
-#[cfg(target_pointer_width = "64")]
-impl_Display!(isize, usize: to_u64);
+impl_Display!(i128, u128 as u128 via to_u128 named fmt_u128);
diff --git a/src/libcore/future/future.rs b/src/libcore/future/future.rs
index 539b07fc21eea..a143b54a61f54 100644
--- a/src/libcore/future/future.rs
+++ b/src/libcore/future/future.rs
@@ -5,7 +5,7 @@
 use marker::Unpin;
 use ops;
 use pin::Pin;
-use task::{Poll, LocalWaker};
+use task::{Poll, Waker};
 
 /// A future represents an asynchronous computation.
 ///
@@ -19,13 +19,15 @@ use task::{Poll, LocalWaker};
 /// final value. This method does not block if the value is not ready. Instead,
 /// the current task is scheduled to be woken up when it's possible to make
 /// further progress by `poll`ing again. The wake up is performed using
-/// `cx.waker()`, a handle for waking up the current task.
+/// the `waker` argument of the `poll()` method, which is a handle for waking
+/// up the current task.
 ///
 /// When using a future, you generally won't call `poll` directly, but instead
 /// `await!` the value.
+#[doc(spotlight)]
 #[must_use = "futures do nothing unless polled"]
 pub trait Future {
-    /// The result of the `Future`.
+    /// The type of value produced on completion.
     type Output;
 
     /// Attempt to resolve the future to a final value, registering
@@ -42,16 +44,16 @@ pub trait Future {
     /// Once a future has finished, clients should not `poll` it again.
     ///
     /// When a future is not ready yet, `poll` returns `Poll::Pending` and
-    /// stores a clone of the [`LocalWaker`] to be woken once the future can
+    /// stores a clone of the [`Waker`] to be woken once the future can
     /// make progress. For example, a future waiting for a socket to become
-    /// readable would call `.clone()` on the [`LocalWaker`] and store it.
+    /// readable would call `.clone()` on the [`Waker`] and store it.
     /// When a signal arrives elsewhere indicating that the socket is readable,
-    /// `[LocalWaker::wake]` is called and the socket future's task is awoken.
+    /// `[Waker::wake]` is called and the socket future's task is awoken.
     /// Once a task has been woken up, it should attempt to `poll` the future
     /// again, which may or may not produce a final value.
     ///
     /// Note that on multiple calls to `poll`, only the most recent
-    /// [`LocalWaker`] passed to `poll` should be scheduled to receive a
+    /// [`Waker`] passed to `poll` should be scheduled to receive a
     /// wakeup.
     ///
     /// # Runtime characteristics
@@ -60,51 +62,42 @@ pub trait Future {
     /// progress, meaning that each time the current task is woken up, it should
     /// actively re-`poll` pending futures that it still has an interest in.
     ///
-    /// The `poll` function is not called repeatedly in a tight loop-- instead,
+    /// The `poll` function is not called repeatedly in a tight loop -- instead,
     /// it should only be called when the future indicates that it is ready to
     /// make progress (by calling `wake()`). If you're familiar with the
     /// `poll(2)` or `select(2)` syscalls on Unix it's worth noting that futures
     /// typically do *not* suffer the same problems of "all wakeups must poll
     /// all events"; they are more like `epoll(4)`.
     ///
-    /// An implementation of `poll` should strive to return quickly, and must
-    /// *never* block. Returning quickly prevents unnecessarily clogging up
+    /// An implementation of `poll` should strive to return quickly, and should
+    /// not block. Returning quickly prevents unnecessarily clogging up
     /// threads or event loops. If it is known ahead of time that a call to
     /// `poll` may end up taking awhile, the work should be offloaded to a
     /// thread pool (or something similar) to ensure that `poll` can return
     /// quickly.
     ///
-    /// # [`LocalWaker`], [`Waker`] and thread-safety
-    ///
-    /// The `poll` function takes a [`LocalWaker`], an object which knows how to
-    /// awaken the current task. [`LocalWaker`] is not `Send` nor `Sync`, so in
-    /// order to make thread-safe futures the [`LocalWaker::into_waker`] method
-    /// should be used to convert the [`LocalWaker`] into a thread-safe version.
-    /// [`LocalWaker::wake`] implementations have the ability to be more
-    /// efficient, however, so when thread safety is not necessary,
-    /// [`LocalWaker`] should be preferred.
+    /// An implementation of `poll` may also never cause memory unsafety.
     ///
     /// # Panics
     ///
     /// Once a future has completed (returned `Ready` from `poll`),
     /// then any future calls to `poll` may panic, block forever, or otherwise
-    /// cause bad behavior. The `Future` trait itself provides no guarantees
-    /// about the behavior of `poll` after a future has completed.
+    /// cause any kind of bad behavior except causing memory unsafety.
+    /// The `Future` trait itself provides no guarantees about the behavior
+    /// of `poll` after a future has completed.
     ///
     /// [`Poll::Pending`]: ../task/enum.Poll.html#variant.Pending
     /// [`Poll::Ready(val)`]: ../task/enum.Poll.html#variant.Ready
-    /// [`LocalWaker`]: ../task/struct.LocalWaker.html
-    /// [`LocalWaker::into_waker`]: ../task/struct.LocalWaker.html#method.into_waker
-    /// [`LocalWaker::wake`]: ../task/struct.LocalWaker.html#method.wake
     /// [`Waker`]: ../task/struct.Waker.html
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output>;
+    /// [`Waker::wake`]: ../task/struct.Waker.html#method.wake
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output>;
 }
 
-impl<'a, F: ?Sized + Future + Unpin> Future for &'a mut F {
+impl<F: ?Sized + Future + Unpin> Future for &mut F {
     type Output = F::Output;
 
-    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        F::poll(Pin::new(&mut **self), lw)
+    fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        F::poll(Pin::new(&mut **self), waker)
     }
 }
 
@@ -115,7 +108,7 @@ where
 {
     type Output = <<P as ops::Deref>::Target as Future>::Output;
 
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        Pin::get_mut(self).as_mut().poll(lw)
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        Pin::get_mut(self).as_mut().poll(waker)
     }
 }
diff --git a/src/libcore/hash/sip.rs b/src/libcore/hash/sip.rs
index 3377b831a9daa..235c79307ab8d 100644
--- a/src/libcore/hash/sip.rs
+++ b/src/libcore/hash/sip.rs
@@ -1,6 +1,6 @@
 //! An implementation of SipHash.
 
-#![allow(deprecated)]
+#![allow(deprecated)] // the types in this module are deprecated
 
 use marker::PhantomData;
 use ptr;
@@ -10,7 +10,7 @@ use mem;
 /// An implementation of SipHash 1-3.
 ///
 /// This is currently the default hashing function used by standard library
-/// (eg. `collections::HashMap` uses it by default).
+/// (e.g., `collections::HashMap` uses it by default).
 ///
 /// See: <https://131002.net/siphash>
 #[unstable(feature = "hashmap_internals", issue = "0")]
@@ -90,7 +90,7 @@ macro_rules! compress {
     });
 }
 
-/// Load an integer of the desired type from a byte stream, in LE order. Uses
+/// Loads an integer of the desired type from a byte stream, in LE order. Uses
 /// `copy_nonoverlapping` to let the compiler generate the most efficient way
 /// to load it from a possibly unaligned address.
 ///
@@ -107,7 +107,7 @@ macro_rules! load_int_le {
     });
 }
 
-/// Load an u64 using up to 7 bytes of a byte slice.
+/// Loads an u64 using up to 7 bytes of a byte slice.
 ///
 /// Unsafe because: unchecked indexing at start..start+len
 #[inline]
diff --git a/src/libcore/hint.rs b/src/libcore/hint.rs
index 9e57a4ebc9919..89de5c1bc8af8 100644
--- a/src/libcore/hint.rs
+++ b/src/libcore/hint.rs
@@ -34,7 +34,7 @@ use intrinsics;
 ///     use std::hint::unreachable_unchecked;
 ///
 ///     // `b.saturating_add(1)` is always positive (not zero),
-///     // hence `checked_div` will never return None.
+///     // hence `checked_div` will never return `None`.
 ///     // Therefore, the else branch is unreachable.
 ///     a.checked_div(b.saturating_add(1))
 ///         .unwrap_or_else(|| unsafe { unreachable_unchecked() })
@@ -49,3 +49,26 @@ use intrinsics;
 pub unsafe fn unreachable_unchecked() -> ! {
     intrinsics::unreachable()
 }
+
+/// Save power or switch hyperthreads in a busy-wait spin-loop.
+///
+/// This function is deliberately more primitive than
+/// [`std::thread::yield_now`](../../std/thread/fn.yield_now.html) and
+/// does not directly yield to the system's scheduler.
+/// In some cases it might be useful to use a combination of both functions.
+/// Careful benchmarking is advised.
+///
+/// On some platforms this function may not do anything at all.
+#[inline]
+#[unstable(feature = "renamed_spin_loop", issue = "55002")]
+pub fn spin_loop() {
+    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+    unsafe {
+        asm!("pause" ::: "memory" : "volatile");
+    }
+
+    #[cfg(target_arch = "aarch64")]
+    unsafe {
+        asm!("yield" ::: "memory" : "volatile");
+    }
+}
diff --git a/src/libcore/internal_macros.rs b/src/libcore/internal_macros.rs
index d12800f712483..faca785e488c3 100644
--- a/src/libcore/internal_macros.rs
+++ b/src/libcore/internal_macros.rs
@@ -7,7 +7,7 @@ macro_rules! forward_ref_unop {
     };
     (impl $imp:ident, $method:ident for $t:ty, #[$attr:meta]) => {
         #[$attr]
-        impl<'a> $imp for &'a $t {
+        impl $imp for &$t {
             type Output = <$t as $imp>::Output;
 
             #[inline]
@@ -75,3 +75,47 @@ macro_rules! forward_ref_op_assign {
         }
     }
 }
+
+/// Create a zero-size type similar to a closure type, but named.
+#[unstable(feature = "std_internals", issue = "0")]
+macro_rules! impl_fn_for_zst {
+    ($(
+        $( #[$attr: meta] )*
+        // FIXME: when libcore is in the 2018 edition, use `?` repetition in
+        // $( <$( $li : lifetime ),+> )?
+        struct $Name: ident impl$( <$( $lifetime : lifetime ),+> )* Fn =
+            |$( $arg: ident: $ArgTy: ty ),*| -> $ReturnTy: ty
+            $body: block;
+    )+) => {
+        $(
+            $( #[$attr] )*
+            struct $Name;
+
+            impl $( <$( $lifetime ),+> )* Fn<($( $ArgTy, )*)> for $Name {
+                #[inline]
+                extern "rust-call" fn call(&self, ($( $arg, )*): ($( $ArgTy, )*)) -> $ReturnTy {
+                    $body
+                }
+            }
+
+            impl $( <$( $lifetime ),+> )* FnMut<($( $ArgTy, )*)> for $Name {
+                #[inline]
+                extern "rust-call" fn call_mut(
+                    &mut self,
+                    ($( $arg, )*): ($( $ArgTy, )*)
+                ) -> $ReturnTy {
+                    Fn::call(&*self, ($( $arg, )*))
+                }
+            }
+
+            impl $( <$( $lifetime ),+> )* FnOnce<($( $ArgTy, )*)> for $Name {
+                type Output = $ReturnTy;
+
+                #[inline]
+                extern "rust-call" fn call_once(self, ($( $arg, )*): ($( $ArgTy, )*)) -> $ReturnTy {
+                    Fn::call(&self, ($( $arg, )*))
+                }
+            }
+        )+
+    }
+}
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index db19baf7a2c64..e6098b1b24cc0 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -1,6 +1,6 @@
-//! rustc compiler intrinsics.
+//! Compiler intrinsics.
 //!
-//! The corresponding definitions are in librustc_codegen_llvm/intrinsic.rs.
+//! The corresponding definitions are in `librustc_codegen_llvm/intrinsic.rs`.
 //!
 //! # Volatiles
 //!
@@ -315,35 +315,35 @@ extern "rust-intrinsic" {
     /// [`AtomicBool::swap`](../../std/sync/atomic/struct.AtomicBool.html#method.swap).
     pub fn atomic_xchg_relaxed<T>(dst: *mut T, src: T) -> T;
 
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::SeqCst`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Acquire`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_acq<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Release`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_rel<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::AcqRel`](../../std/sync/atomic/enum.Ordering.html)
     /// as the `order`. For example,
     /// [`AtomicIsize::fetch_add`](../../std/sync/atomic/struct.AtomicIsize.html#method.fetch_add).
     pub fn atomic_xadd_acqrel<T>(dst: *mut T, src: T) -> T;
-    /// Add to the current value, returning the previous value.
+    /// Adds to the current value, returning the previous value.
     /// The stabilized version of this intrinsic is available on the
     /// `std::sync::atomic` types via the `fetch_add` method by passing
     /// [`Ordering::Relaxed`](../../std/sync/atomic/enum.Ordering.html)
@@ -556,7 +556,7 @@ extern "rust-intrinsic" {
     pub fn atomic_umax_relaxed<T>(dst: *mut T, src: T) -> T;
 
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -564,7 +564,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_read_data<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -572,7 +572,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_write_data<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -580,7 +580,7 @@ extern "rust-intrinsic" {
     /// ranging from (0) - no locality, to (3) - extremely local keep in cache
     pub fn prefetch_read_instruction<T>(data: *const T, locality: i32);
     /// The `prefetch` intrinsic is a hint to the code generator to insert a prefetch instruction
-    /// if supported; otherwise, it is a noop.
+    /// if supported; otherwise, it is a no-op.
     /// Prefetches have no effect on the behavior of the program but can change its performance
     /// characteristics.
     ///
@@ -692,13 +692,12 @@ extern "rust-intrinsic" {
 
     /// A guard for unsafe functions that cannot ever be executed if `T` is uninhabited:
     /// This will statically either panic, or do nothing.
-    #[cfg(not(stage0))]
     pub fn panic_if_uninhabited<T>();
 
     /// Creates a value initialized to zero.
     ///
     /// `init` is unsafe because it returns a zeroed-out datum,
-    /// which is unsafe unless T is `Copy`.  Also, even if T is
+    /// which is unsafe unless `T` is `Copy`. Also, even if T is
     /// `Copy`, an all-zero value may not correspond to any legitimate
     /// state for the type in question.
     pub fn init<T>() -> T;
@@ -858,7 +857,7 @@ extern "rust-intrinsic" {
     ///
     /// // The no-copy, unsafe way, still using transmute, but not UB.
     /// // This is equivalent to the original, but safer, and reuses the
-    /// // same Vec internals. Therefore the new inner type must have the
+    /// // same `Vec` internals. Therefore, the new inner type must have the
     /// // exact same size, and the same alignment, as the old type.
     /// // The same caveats exist for this method as transmute, for
     /// // the original inner type (`&i32`) to the converted inner type
@@ -876,8 +875,8 @@ extern "rust-intrinsic" {
     /// ```
     /// use std::{slice, mem};
     ///
-    /// // There are multiple ways to do this; and there are multiple problems
-    /// // with the following, transmute, way.
+    /// // There are multiple ways to do this, and there are multiple problems
+    /// // with the following (transmute) way.
     /// fn split_at_mut_transmute<T>(slice: &mut [T], mid: usize)
     ///                              -> (&mut [T], &mut [T]) {
     ///     let len = slice.len();
@@ -963,221 +962,6 @@ extern "rust-intrinsic" {
     /// value is not necessarily valid to be used to actually access memory.
     pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T;
 
-    /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
-    /// and destination must *not* overlap.
-    ///
-    /// For regions of memory which might overlap, use [`copy`] instead.
-    ///
-    /// `copy_nonoverlapping` is semantically equivalent to C's [`memcpy`], but
-    /// with the argument order swapped.
-    ///
-    /// [`copy`]: ./fn.copy.html
-    /// [`memcpy`]: https://en.cppreference.com/w/c/string/byte/memcpy
-    ///
-    /// # Safety
-    ///
-    /// Behavior is undefined if any of the following conditions are violated:
-    ///
-    /// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
-    ///
-    /// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
-    ///
-    /// * Both `src` and `dst` must be properly aligned.
-    ///
-    /// * The region of memory beginning at `src` with a size of `count *
-    ///   size_of::<T>()` bytes must *not* overlap with the region of memory
-    ///   beginning at `dst` with the same size.
-    ///
-    /// Like [`read`], `copy_nonoverlapping` creates a bitwise copy of `T`, regardless of
-    /// whether `T` is [`Copy`].  If `T` is not [`Copy`], using *both* the values
-    /// in the region beginning at `*src` and the region beginning at `*dst` can
-    /// [violate memory safety][read-ownership].
-    ///
-    /// Note that even if the effectively copied size (`count * size_of::<T>()`) is
-    /// `0`, the pointers must be non-NULL and properly aligned.
-    ///
-    /// [`Copy`]: ../marker/trait.Copy.html
-    /// [`read`]: ../ptr/fn.read.html
-    /// [read-ownership]: ../ptr/fn.read.html#ownership-of-the-returned-value
-    /// [valid]: ../ptr/index.html#safety
-    ///
-    /// # Examples
-    ///
-    /// Manually implement [`Vec::append`]:
-    ///
-    /// ```
-    /// use std::ptr;
-    ///
-    /// /// Moves all the elements of `src` into `dst`, leaving `src` empty.
-    /// fn append<T>(dst: &mut Vec<T>, src: &mut Vec<T>) {
-    ///     let src_len = src.len();
-    ///     let dst_len = dst.len();
-    ///
-    ///     // Ensure that `dst` has enough capacity to hold all of `src`.
-    ///     dst.reserve(src_len);
-    ///
-    ///     unsafe {
-    ///         // The call to offset is always safe because `Vec` will never
-    ///         // allocate more than `isize::MAX` bytes.
-    ///         let dst_ptr = dst.as_mut_ptr().offset(dst_len as isize);
-    ///         let src_ptr = src.as_ptr();
-    ///
-    ///         // Truncate `src` without dropping its contents. We do this first,
-    ///         // to avoid problems in case something further down panics.
-    ///         src.set_len(0);
-    ///
-    ///         // The two regions cannot overlap because mutable references do
-    ///         // not alias, and two different vectors cannot own the same
-    ///         // memory.
-    ///         ptr::copy_nonoverlapping(src_ptr, dst_ptr, src_len);
-    ///
-    ///         // Notify `dst` that it now holds the contents of `src`.
-    ///         dst.set_len(dst_len + src_len);
-    ///     }
-    /// }
-    ///
-    /// let mut a = vec!['r'];
-    /// let mut b = vec!['u', 's', 't'];
-    ///
-    /// append(&mut a, &mut b);
-    ///
-    /// assert_eq!(a, &['r', 'u', 's', 't']);
-    /// assert!(b.is_empty());
-    /// ```
-    ///
-    /// [`Vec::append`]: ../../std/vec/struct.Vec.html#method.append
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
-
-    /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
-    /// and destination may overlap.
-    ///
-    /// If the source and destination will *never* overlap,
-    /// [`copy_nonoverlapping`] can be used instead.
-    ///
-    /// `copy` is semantically equivalent to C's [`memmove`], but with the argument
-    /// order swapped.  Copying takes place as if the bytes were copied from `src`
-    /// to a temporary array and then copied from the array to `dst`.
-    ///
-    /// [`copy_nonoverlapping`]: ./fn.copy_nonoverlapping.html
-    /// [`memmove`]: https://en.cppreference.com/w/c/string/byte/memmove
-    ///
-    /// # Safety
-    ///
-    /// Behavior is undefined if any of the following conditions are violated:
-    ///
-    /// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
-    ///
-    /// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
-    ///
-    /// * Both `src` and `dst` must be properly aligned.
-    ///
-    /// Like [`read`], `copy` creates a bitwise copy of `T`, regardless of
-    /// whether `T` is [`Copy`].  If `T` is not [`Copy`], using both the values
-    /// in the region beginning at `*src` and the region beginning at `*dst` can
-    /// [violate memory safety][read-ownership].
-    ///
-    /// Note that even if the effectively copied size (`count * size_of::<T>()`) is
-    /// `0`, the pointers must be non-NULL and properly aligned.
-    ///
-    /// [`Copy`]: ../marker/trait.Copy.html
-    /// [`read`]: ../ptr/fn.read.html
-    /// [read-ownership]: ../ptr/fn.read.html#ownership-of-the-returned-value
-    /// [valid]: ../ptr/index.html#safety
-    ///
-    /// # Examples
-    ///
-    /// Efficiently create a Rust vector from an unsafe buffer:
-    ///
-    /// ```
-    /// use std::ptr;
-    ///
-    /// # #[allow(dead_code)]
-    /// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
-    ///     let mut dst = Vec::with_capacity(elts);
-    ///     dst.set_len(elts);
-    ///     ptr::copy(ptr, dst.as_mut_ptr(), elts);
-    ///     dst
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn copy<T>(src: *const T, dst: *mut T, count: usize);
-
-    /// Sets `count * size_of::<T>()` bytes of memory starting at `dst` to
-    /// `val`.
-    ///
-    /// `write_bytes` is similar to C's [`memset`], but sets `count *
-    /// size_of::<T>()` bytes to `val`.
-    ///
-    /// [`memset`]: https://en.cppreference.com/w/c/string/byte/memset
-    ///
-    /// # Safety
-    ///
-    /// Behavior is undefined if any of the following conditions are violated:
-    ///
-    /// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
-    ///
-    /// * `dst` must be properly aligned.
-    ///
-    /// Additionally, the caller must ensure that writing `count *
-    /// size_of::<T>()` bytes to the given region of memory results in a valid
-    /// value of `T`. Using a region of memory typed as a `T` that contains an
-    /// invalid value of `T` is undefined behavior.
-    ///
-    /// Note that even if the effectively copied size (`count * size_of::<T>()`) is
-    /// `0`, the pointer must be non-NULL and properly aligned.
-    ///
-    /// [valid]: ../ptr/index.html#safety
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// use std::ptr;
-    ///
-    /// let mut vec = vec![0u32; 4];
-    /// unsafe {
-    ///     let vec_ptr = vec.as_mut_ptr();
-    ///     ptr::write_bytes(vec_ptr, 0xfe, 2);
-    /// }
-    /// assert_eq!(vec, [0xfefefefe, 0xfefefefe, 0, 0]);
-    /// ```
-    ///
-    /// Creating an invalid value:
-    ///
-    /// ```
-    /// use std::ptr;
-    ///
-    /// let mut v = Box::new(0i32);
-    ///
-    /// unsafe {
-    ///     // Leaks the previously held value by overwriting the `Box<T>` with
-    ///     // a null pointer.
-    ///     ptr::write_bytes(&mut v as *mut Box<i32>, 0, 1);
-    /// }
-    ///
-    /// // At this point, using or dropping `v` results in undefined behavior.
-    /// // drop(v); // ERROR
-    ///
-    /// // Even leaking `v` "uses" it, and hence is undefined behavior.
-    /// // mem::forget(v); // ERROR
-    ///
-    /// // In fact, `v` is invalid according to basic type layout invariants, so *any*
-    /// // operation touching it is undefined behavior.
-    /// // let v2 = v; // ERROR
-    ///
-    /// unsafe {
-    ///     // Let us instead put in a valid value
-    ///     ptr::write(&mut v as *mut Box<i32>, Box::new(42i32));
-    /// }
-    ///
-    /// // Now the box is fine
-    /// assert_eq!(*v, 42);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
-
     /// Equivalent to the appropriate `llvm.memcpy.p0i8.0i8.*` intrinsic, with
     /// a size of `count` * `size_of::<T>()` and an alignment of
     /// `min_align_of::<T>()`
@@ -1201,19 +985,19 @@ extern "rust-intrinsic" {
     /// unless size is equal to zero.
     pub fn volatile_set_memory<T>(dst: *mut T, val: u8, count: usize);
 
-    /// Perform a volatile load from the `src` pointer.
+    /// Performs a volatile load from the `src` pointer.
     /// The stabilized version of this intrinsic is
     /// [`std::ptr::read_volatile`](../../std/ptr/fn.read_volatile.html).
     pub fn volatile_load<T>(src: *const T) -> T;
-    /// Perform a volatile store to the `dst` pointer.
+    /// Performs a volatile store to the `dst` pointer.
     /// The stabilized version of this intrinsic is
     /// [`std::ptr::write_volatile`](../../std/ptr/fn.write_volatile.html).
     pub fn volatile_store<T>(dst: *mut T, val: T);
 
-    /// Perform a volatile load from the `src` pointer
+    /// Performs a volatile load from the `src` pointer
     /// The pointer is not required to be aligned.
     pub fn unaligned_volatile_load<T>(src: *const T) -> T;
-    /// Perform a volatile store to the `dst` pointer.
+    /// Performs a volatile store to the `dst` pointer.
     /// The pointer is not required to be aligned.
     pub fn unaligned_volatile_store<T>(dst: *mut T, val: T);
 
@@ -1494,6 +1278,19 @@ extern "rust-intrinsic" {
     /// [`std::u32::wrapping_mul`](../../std/primitive.u32.html#method.wrapping_mul)
     pub fn overflowing_mul<T>(a: T, b: T) -> T;
 
+    /// Computes `a + b`, while saturating at numeric bounds.
+    /// The stabilized versions of this intrinsic are available on the integer
+    /// primitives via the `saturating_add` method. For example,
+    /// [`std::u32::saturating_add`](../../std/primitive.u32.html#method.saturating_add)
+    #[cfg(not(stage0))]
+    pub fn saturating_add<T>(a: T, b: T) -> T;
+    /// Computes `a - b`, while saturating at numeric bounds.
+    /// The stabilized versions of this intrinsic are available on the integer
+    /// primitives via the `saturating_sub` method. For example,
+    /// [`std::u32::saturating_sub`](../../std/primitive.u32.html#method.saturating_sub)
+    #[cfg(not(stage0))]
+    pub fn saturating_sub<T>(a: T, b: T) -> T;
+
     /// Returns the value of the discriminant for the variant in 'v',
     /// cast to a `u64`; if `T` has no discriminant, returns 0.
     pub fn discriminant_value<T>(v: &T) -> u64;
@@ -1512,3 +1309,252 @@ extern "rust-intrinsic" {
     /// Probably will never become stable.
     pub fn nontemporal_store<T>(ptr: *mut T, val: T);
 }
+
+mod real_intrinsics {
+  extern "rust-intrinsic" {
+    /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
+    /// and destination must *not* overlap.
+    /// For the full docs, see the stabilized wrapper [`copy_nonoverlapping`].
+    ///
+    /// [`copy_nonoverlapping`]: ../../std/ptr/fn.copy_nonoverlapping.html
+    pub fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
+
+    /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
+    /// and destination may overlap.
+    /// For the full docs, see the stabilized wrapper [`copy`].
+    ///
+    /// [`copy`]: ../../std/ptr/fn.copy.html
+    pub fn copy<T>(src: *const T, dst: *mut T, count: usize);
+
+    /// Sets `count * size_of::<T>()` bytes of memory starting at `dst` to
+    /// `val`.
+    /// For the full docs, see the stabilized wrapper [`write_bytes`].
+    ///
+    /// [`write_bytes`]: ../../std/ptr/fn.write_bytes.html
+    pub fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
+  }
+}
+
+/// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
+/// and destination must *not* overlap.
+///
+/// For regions of memory which might overlap, use [`copy`] instead.
+///
+/// `copy_nonoverlapping` is semantically equivalent to C's [`memcpy`], but
+/// with the argument order swapped.
+///
+/// [`copy`]: ./fn.copy.html
+/// [`memcpy`]: https://en.cppreference.com/w/c/string/byte/memcpy
+///
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+///
+/// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
+///
+/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
+///
+/// * Both `src` and `dst` must be properly aligned.
+///
+/// * The region of memory beginning at `src` with a size of `count *
+///   size_of::<T>()` bytes must *not* overlap with the region of memory
+///   beginning at `dst` with the same size.
+///
+/// Like [`read`], `copy_nonoverlapping` creates a bitwise copy of `T`, regardless of
+/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using *both* the values
+/// in the region beginning at `*src` and the region beginning at `*dst` can
+/// [violate memory safety][read-ownership].
+///
+/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
+/// `0`, the pointers must be non-NULL and properly aligned.
+///
+/// [`Copy`]: ../marker/trait.Copy.html
+/// [`read`]: ../ptr/fn.read.html
+/// [read-ownership]: ../ptr/fn.read.html#ownership-of-the-returned-value
+/// [valid]: ../ptr/index.html#safety
+///
+/// # Examples
+///
+/// Manually implement [`Vec::append`]:
+///
+/// ```
+/// use std::ptr;
+///
+/// /// Moves all the elements of `src` into `dst`, leaving `src` empty.
+/// fn append<T>(dst: &mut Vec<T>, src: &mut Vec<T>) {
+///     let src_len = src.len();
+///     let dst_len = dst.len();
+///
+///     // Ensure that `dst` has enough capacity to hold all of `src`.
+///     dst.reserve(src_len);
+///
+///     unsafe {
+///         // The call to offset is always safe because `Vec` will never
+///         // allocate more than `isize::MAX` bytes.
+///         let dst_ptr = dst.as_mut_ptr().offset(dst_len as isize);
+///         let src_ptr = src.as_ptr();
+///
+///         // Truncate `src` without dropping its contents. We do this first,
+///         // to avoid problems in case something further down panics.
+///         src.set_len(0);
+///
+///         // The two regions cannot overlap because mutable references do
+///         // not alias, and two different vectors cannot own the same
+///         // memory.
+///         ptr::copy_nonoverlapping(src_ptr, dst_ptr, src_len);
+///
+///         // Notify `dst` that it now holds the contents of `src`.
+///         dst.set_len(dst_len + src_len);
+///     }
+/// }
+///
+/// let mut a = vec!['r'];
+/// let mut b = vec!['u', 's', 't'];
+///
+/// append(&mut a, &mut b);
+///
+/// assert_eq!(a, &['r', 'u', 's', 't']);
+/// assert!(b.is_empty());
+/// ```
+///
+/// [`Vec::append`]: ../../std/vec/struct.Vec.html#method.append
+#[stable(feature = "rust1", since = "1.0.0")]
+#[inline]
+pub unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize) {
+    real_intrinsics::copy_nonoverlapping(src, dst, count);
+}
+
+/// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
+/// and destination may overlap.
+///
+/// If the source and destination will *never* overlap,
+/// [`copy_nonoverlapping`] can be used instead.
+///
+/// `copy` is semantically equivalent to C's [`memmove`], but with the argument
+/// order swapped. Copying takes place as if the bytes were copied from `src`
+/// to a temporary array and then copied from the array to `dst`.
+///
+/// [`copy_nonoverlapping`]: ./fn.copy_nonoverlapping.html
+/// [`memmove`]: https://en.cppreference.com/w/c/string/byte/memmove
+///
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+///
+/// * `src` must be [valid] for reads of `count * size_of::<T>()` bytes.
+///
+/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
+///
+/// * Both `src` and `dst` must be properly aligned.
+///
+/// Like [`read`], `copy` creates a bitwise copy of `T`, regardless of
+/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using both the values
+/// in the region beginning at `*src` and the region beginning at `*dst` can
+/// [violate memory safety][read-ownership].
+///
+/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
+/// `0`, the pointers must be non-NULL and properly aligned.
+///
+/// [`Copy`]: ../marker/trait.Copy.html
+/// [`read`]: ../ptr/fn.read.html
+/// [read-ownership]: ../ptr/fn.read.html#ownership-of-the-returned-value
+/// [valid]: ../ptr/index.html#safety
+///
+/// # Examples
+///
+/// Efficiently create a Rust vector from an unsafe buffer:
+///
+/// ```
+/// use std::ptr;
+///
+/// # #[allow(dead_code)]
+/// unsafe fn from_buf_raw<T>(ptr: *const T, elts: usize) -> Vec<T> {
+///     let mut dst = Vec::with_capacity(elts);
+///     dst.set_len(elts);
+///     ptr::copy(ptr, dst.as_mut_ptr(), elts);
+///     dst
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[inline]
+pub unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
+    real_intrinsics::copy(src, dst, count)
+}
+
+/// Sets `count * size_of::<T>()` bytes of memory starting at `dst` to
+/// `val`.
+///
+/// `write_bytes` is similar to C's [`memset`], but sets `count *
+/// size_of::<T>()` bytes to `val`.
+///
+/// [`memset`]: https://en.cppreference.com/w/c/string/byte/memset
+///
+/// # Safety
+///
+/// Behavior is undefined if any of the following conditions are violated:
+///
+/// * `dst` must be [valid] for writes of `count * size_of::<T>()` bytes.
+///
+/// * `dst` must be properly aligned.
+///
+/// Additionally, the caller must ensure that writing `count *
+/// size_of::<T>()` bytes to the given region of memory results in a valid
+/// value of `T`. Using a region of memory typed as a `T` that contains an
+/// invalid value of `T` is undefined behavior.
+///
+/// Note that even if the effectively copied size (`count * size_of::<T>()`) is
+/// `0`, the pointer must be non-NULL and properly aligned.
+///
+/// [valid]: ../ptr/index.html#safety
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// use std::ptr;
+///
+/// let mut vec = vec![0u32; 4];
+/// unsafe {
+///     let vec_ptr = vec.as_mut_ptr();
+///     ptr::write_bytes(vec_ptr, 0xfe, 2);
+/// }
+/// assert_eq!(vec, [0xfefefefe, 0xfefefefe, 0, 0]);
+/// ```
+///
+/// Creating an invalid value:
+///
+/// ```
+/// use std::ptr;
+///
+/// let mut v = Box::new(0i32);
+///
+/// unsafe {
+///     // Leaks the previously held value by overwriting the `Box<T>` with
+///     // a null pointer.
+///     ptr::write_bytes(&mut v as *mut Box<i32>, 0, 1);
+/// }
+///
+/// // At this point, using or dropping `v` results in undefined behavior.
+/// // drop(v); // ERROR
+///
+/// // Even leaking `v` "uses" it, and hence is undefined behavior.
+/// // mem::forget(v); // ERROR
+///
+/// // In fact, `v` is invalid according to basic type layout invariants, so *any*
+/// // operation touching it is undefined behavior.
+/// // let v2 = v; // ERROR
+///
+/// unsafe {
+///     // Let us instead put in a valid value
+///     ptr::write(&mut v as *mut Box<i32>, Box::new(42i32));
+/// }
+///
+/// // Now the box is fine
+/// assert_eq!(*v, 42);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[inline]
+pub unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
+    real_intrinsics::write_bytes(dst, val, count)
+}
diff --git a/src/libcore/iter/adapters/chain.rs b/src/libcore/iter/adapters/chain.rs
new file mode 100644
index 0000000000000..573b096fb463e
--- /dev/null
+++ b/src/libcore/iter/adapters/chain.rs
@@ -0,0 +1,260 @@
+use ops::Try;
+use usize;
+use super::super::{Iterator, DoubleEndedIterator, FusedIterator, TrustedLen};
+
+/// An iterator that strings two iterators together.
+///
+/// This `struct` is created by the [`chain`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`chain`]: trait.Iterator.html#method.chain
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Chain<A, B> {
+    a: A,
+    b: B,
+    state: ChainState,
+}
+impl<A, B> Chain<A, B> {
+    pub(in super::super) fn new(a: A, b: B) -> Chain<A, B> {
+        Chain { a, b, state: ChainState::Both }
+    }
+}
+
+// The iterator protocol specifies that iteration ends with the return value
+// `None` from `.next()` (or `.next_back()`) and it is unspecified what
+// further calls return. The chain adaptor must account for this since it uses
+// two subiterators.
+//
+//  It uses three states:
+//
+//  - Both: `a` and `b` are remaining
+//  - Front: `a` remaining
+//  - Back: `b` remaining
+//
+//  The fourth state (neither iterator is remaining) only occurs after Chain has
+//  returned None once, so we don't need to store this state.
+#[derive(Clone, Debug)]
+enum ChainState {
+    // both front and back iterator are remaining
+    Both,
+    // only front is remaining
+    Front,
+    // only back is remaining
+    Back,
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> Iterator for Chain<A, B> where
+    A: Iterator,
+    B: Iterator<Item = A::Item>
+{
+    type Item = A::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<A::Item> {
+        match self.state {
+            ChainState::Both => match self.a.next() {
+                elt @ Some(..) => elt,
+                None => {
+                    self.state = ChainState::Back;
+                    self.b.next()
+                }
+            },
+            ChainState::Front => self.a.next(),
+            ChainState::Back => self.b.next(),
+        }
+    }
+
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn count(self) -> usize {
+        match self.state {
+            ChainState::Both => self.a.count() + self.b.count(),
+            ChainState::Front => self.a.count(),
+            ChainState::Back => self.b.count(),
+        }
+    }
+
+    fn try_fold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R where
+        Self: Sized, F: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let mut accum = init;
+        match self.state {
+            ChainState::Both | ChainState::Front => {
+                accum = self.a.try_fold(accum, &mut f)?;
+                if let ChainState::Both = self.state {
+                    self.state = ChainState::Back;
+                }
+            }
+            _ => { }
+        }
+        if let ChainState::Back = self.state {
+            accum = self.b.try_fold(accum, &mut f)?;
+        }
+        Try::from_ok(accum)
+    }
+
+    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut accum = init;
+        match self.state {
+            ChainState::Both | ChainState::Front => {
+                accum = self.a.fold(accum, &mut f);
+            }
+            _ => { }
+        }
+        match self.state {
+            ChainState::Both | ChainState::Back => {
+                accum = self.b.fold(accum, &mut f);
+            }
+            _ => { }
+        }
+        accum
+    }
+
+    #[inline]
+    fn nth(&mut self, mut n: usize) -> Option<A::Item> {
+        match self.state {
+            ChainState::Both | ChainState::Front => {
+                for x in self.a.by_ref() {
+                    if n == 0 {
+                        return Some(x)
+                    }
+                    n -= 1;
+                }
+                if let ChainState::Both = self.state {
+                    self.state = ChainState::Back;
+                }
+            }
+            ChainState::Back => {}
+        }
+        if let ChainState::Back = self.state {
+            self.b.nth(n)
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn find<P>(&mut self, mut predicate: P) -> Option<Self::Item> where
+        P: FnMut(&Self::Item) -> bool,
+    {
+        match self.state {
+            ChainState::Both => match self.a.find(&mut predicate) {
+                None => {
+                    self.state = ChainState::Back;
+                    self.b.find(predicate)
+                }
+                v => v
+            },
+            ChainState::Front => self.a.find(predicate),
+            ChainState::Back => self.b.find(predicate),
+        }
+    }
+
+    #[inline]
+    fn last(self) -> Option<A::Item> {
+        match self.state {
+            ChainState::Both => {
+                // Must exhaust a before b.
+                let a_last = self.a.last();
+                let b_last = self.b.last();
+                b_last.or(a_last)
+            },
+            ChainState::Front => self.a.last(),
+            ChainState::Back => self.b.last()
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (a_lower, a_upper) = self.a.size_hint();
+        let (b_lower, b_upper) = self.b.size_hint();
+
+        let lower = a_lower.saturating_add(b_lower);
+
+        let upper = match (a_upper, b_upper) {
+            (Some(x), Some(y)) => x.checked_add(y),
+            _ => None
+        };
+
+        (lower, upper)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> DoubleEndedIterator for Chain<A, B> where
+    A: DoubleEndedIterator,
+    B: DoubleEndedIterator<Item=A::Item>,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<A::Item> {
+        match self.state {
+            ChainState::Both => match self.b.next_back() {
+                elt @ Some(..) => elt,
+                None => {
+                    self.state = ChainState::Front;
+                    self.a.next_back()
+                }
+            },
+            ChainState::Front => self.a.next_back(),
+            ChainState::Back => self.b.next_back(),
+        }
+    }
+
+    fn try_rfold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R where
+        Self: Sized, F: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let mut accum = init;
+        match self.state {
+            ChainState::Both | ChainState::Back => {
+                accum = self.b.try_rfold(accum, &mut f)?;
+                if let ChainState::Both = self.state {
+                    self.state = ChainState::Front;
+                }
+            }
+            _ => { }
+        }
+        if let ChainState::Front = self.state {
+            accum = self.a.try_rfold(accum, &mut f)?;
+        }
+        Try::from_ok(accum)
+    }
+
+    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut accum = init;
+        match self.state {
+            ChainState::Both | ChainState::Back => {
+                accum = self.b.rfold(accum, &mut f);
+            }
+            _ => { }
+        }
+        match self.state {
+            ChainState::Both | ChainState::Front => {
+                accum = self.a.rfold(accum, &mut f);
+            }
+            _ => { }
+        }
+        accum
+    }
+
+}
+
+// Note: *both* must be fused to handle double-ended iterators.
+#[stable(feature = "fused", since = "1.26.0")]
+impl<A, B> FusedIterator for Chain<A, B>
+    where A: FusedIterator,
+          B: FusedIterator<Item=A::Item>,
+{}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<A, B> TrustedLen for Chain<A, B>
+    where A: TrustedLen, B: TrustedLen<Item=A::Item>,
+{}
+
diff --git a/src/libcore/iter/adapters/flatten.rs b/src/libcore/iter/adapters/flatten.rs
new file mode 100644
index 0000000000000..40f6865d38bcf
--- /dev/null
+++ b/src/libcore/iter/adapters/flatten.rs
@@ -0,0 +1,330 @@
+use fmt;
+use ops::Try;
+use super::super::{Iterator, DoubleEndedIterator, FusedIterator};
+use super::Map;
+
+/// An iterator that maps each element to an iterator, and yields the elements
+/// of the produced iterators.
+///
+/// This `struct` is created by the [`flat_map`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`flat_map`]: trait.Iterator.html#method.flat_map
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct FlatMap<I, U: IntoIterator, F> {
+    inner: FlattenCompat<Map<I, F>, <U as IntoIterator>::IntoIter>
+}
+impl<I: Iterator, U: IntoIterator, F: FnMut(I::Item) -> U> FlatMap<I, U, F> {
+    pub(in super::super) fn new(iter: I, f: F) -> FlatMap<I, U, F> {
+        FlatMap { inner: FlattenCompat::new(iter.map(f)) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Clone, U: Clone + IntoIterator, F: Clone> Clone for FlatMap<I, U, F>
+    where <U as IntoIterator>::IntoIter: Clone
+{
+    fn clone(&self) -> Self { FlatMap { inner: self.inner.clone() } }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, U: IntoIterator, F> fmt::Debug for FlatMap<I, U, F>
+    where U::IntoIter: fmt::Debug
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("FlatMap").field("inner", &self.inner).finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F>
+    where F: FnMut(I::Item) -> U,
+{
+    type Item = U::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<U::Item> { self.inner.next() }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.inner.try_fold(init, fold)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.inner.fold(init, fold)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: DoubleEndedIterator, U, F> DoubleEndedIterator for FlatMap<I, U, F>
+    where F: FnMut(I::Item) -> U,
+          U: IntoIterator,
+          U::IntoIter: DoubleEndedIterator
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<U::Item> { self.inner.next_back() }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.inner.try_rfold(init, fold)
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.inner.rfold(init, fold)
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I, U, F> FusedIterator for FlatMap<I, U, F>
+    where I: FusedIterator, U: IntoIterator, F: FnMut(I::Item) -> U {}
+
+/// An iterator that flattens one level of nesting in an iterator of things
+/// that can be turned into iterators.
+///
+/// This `struct` is created by the [`flatten`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`flatten`]: trait.Iterator.html#method.flatten
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+pub struct Flatten<I: Iterator>
+where I::Item: IntoIterator {
+    inner: FlattenCompat<I, <I::Item as IntoIterator>::IntoIter>,
+}
+impl<I: Iterator> Flatten<I>
+where I::Item: IntoIterator {
+    pub(in super::super) fn new(iter: I) -> Flatten<I> {
+        Flatten { inner: FlattenCompat::new(iter) }
+    }
+}
+
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+impl<I, U> fmt::Debug for Flatten<I>
+    where I: Iterator + fmt::Debug, U: Iterator + fmt::Debug,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Flatten").field("inner", &self.inner).finish()
+    }
+}
+
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+impl<I, U> Clone for Flatten<I>
+    where I: Iterator + Clone, U: Iterator + Clone,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>,
+{
+    fn clone(&self) -> Self { Flatten { inner: self.inner.clone() } }
+}
+
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+impl<I, U> Iterator for Flatten<I>
+    where I: Iterator, U: Iterator,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
+{
+    type Item = U::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<U::Item> { self.inner.next() }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.inner.try_fold(init, fold)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.inner.fold(init, fold)
+    }
+}
+
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+impl<I, U> DoubleEndedIterator for Flatten<I>
+    where I: DoubleEndedIterator, U: DoubleEndedIterator,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<U::Item> { self.inner.next_back() }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.inner.try_rfold(init, fold)
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.inner.rfold(init, fold)
+    }
+}
+
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+impl<I, U> FusedIterator for Flatten<I>
+    where I: FusedIterator, U: Iterator,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item> {}
+
+/// Real logic of both `Flatten` and `FlatMap` which simply delegate to
+/// this type.
+#[derive(Clone, Debug)]
+struct FlattenCompat<I, U> {
+    iter: I,
+    frontiter: Option<U>,
+    backiter: Option<U>,
+}
+impl<I, U> FlattenCompat<I, U> {
+    /// Adapts an iterator by flattening it, for use in `flatten()` and `flat_map()`.
+    fn new(iter: I) -> FlattenCompat<I, U> {
+        FlattenCompat { iter, frontiter: None, backiter: None }
+    }
+}
+
+impl<I, U> Iterator for FlattenCompat<I, U>
+    where I: Iterator, U: Iterator,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
+{
+    type Item = U::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<U::Item> {
+        loop {
+            if let Some(ref mut inner) = self.frontiter {
+                if let elt@Some(_) = inner.next() { return elt }
+            }
+            match self.iter.next() {
+                None => return self.backiter.as_mut().and_then(|it| it.next()),
+                Some(inner) => self.frontiter = Some(inner.into_iter()),
+            }
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (flo, fhi) = self.frontiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
+        let (blo, bhi) = self.backiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
+        let lo = flo.saturating_add(blo);
+        match (self.iter.size_hint(), fhi, bhi) {
+            ((0, Some(0)), Some(a), Some(b)) => (lo, a.checked_add(b)),
+            _ => (lo, None)
+        }
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if let Some(ref mut front) = self.frontiter {
+            init = front.try_fold(init, &mut fold)?;
+        }
+        self.frontiter = None;
+
+        {
+            let frontiter = &mut self.frontiter;
+            init = self.iter.try_fold(init, |acc, x| {
+                let mut mid = x.into_iter();
+                let r = mid.try_fold(acc, &mut fold);
+                *frontiter = Some(mid);
+                r
+            })?;
+        }
+        self.frontiter = None;
+
+        if let Some(ref mut back) = self.backiter {
+            init = back.try_fold(init, &mut fold)?;
+        }
+        self.backiter = None;
+
+        Try::from_ok(init)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.frontiter.into_iter()
+            .chain(self.iter.map(IntoIterator::into_iter))
+            .chain(self.backiter)
+            .fold(init, |acc, iter| iter.fold(acc, &mut fold))
+    }
+}
+
+impl<I, U> DoubleEndedIterator for FlattenCompat<I, U>
+    where I: DoubleEndedIterator, U: DoubleEndedIterator,
+          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<U::Item> {
+        loop {
+            if let Some(ref mut inner) = self.backiter {
+                if let elt@Some(_) = inner.next_back() { return elt }
+            }
+            match self.iter.next_back() {
+                None => return self.frontiter.as_mut().and_then(|it| it.next_back()),
+                next => self.backiter = next.map(IntoIterator::into_iter),
+            }
+        }
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if let Some(ref mut back) = self.backiter {
+            init = back.try_rfold(init, &mut fold)?;
+        }
+        self.backiter = None;
+
+        {
+            let backiter = &mut self.backiter;
+            init = self.iter.try_rfold(init, |acc, x| {
+                let mut mid = x.into_iter();
+                let r = mid.try_rfold(acc, &mut fold);
+                *backiter = Some(mid);
+                r
+            })?;
+        }
+        self.backiter = None;
+
+        if let Some(ref mut front) = self.frontiter {
+            init = front.try_rfold(init, &mut fold)?;
+        }
+        self.frontiter = None;
+
+        Try::from_ok(init)
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.frontiter.into_iter()
+            .chain(self.iter.map(IntoIterator::into_iter))
+            .chain(self.backiter)
+            .rfold(init, |acc, iter| iter.rfold(acc, &mut fold))
+    }
+}
+
diff --git a/src/libcore/iter/adapters/mod.rs b/src/libcore/iter/adapters/mod.rs
new file mode 100644
index 0000000000000..bca1b76dbb975
--- /dev/null
+++ b/src/libcore/iter/adapters/mod.rs
@@ -0,0 +1,2045 @@
+use cmp;
+use fmt;
+use ops::Try;
+use usize;
+use intrinsics;
+use super::{Iterator, DoubleEndedIterator, ExactSizeIterator, FusedIterator, TrustedLen};
+use super::LoopState;
+
+mod chain;
+mod flatten;
+mod zip;
+
+pub use self::chain::Chain;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::flatten::{FlatMap, Flatten};
+pub use self::zip::Zip;
+pub(crate) use self::zip::TrustedRandomAccess;
+
+/// A double-ended iterator with the direction inverted.
+///
+/// This `struct` is created by the [`rev`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`rev`]: trait.Iterator.html#method.rev
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Rev<T> {
+    iter: T
+}
+impl<T> Rev<T> {
+    pub(super) fn new(iter: T) -> Rev<T> {
+        Rev { iter }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
+    type Item = <I as Iterator>::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next_back() }
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item> { self.iter.nth_back(n) }
+
+    fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.iter.try_rfold(init, f)
+    }
+
+    fn fold<Acc, F>(self, init: Acc, f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.iter.rfold(init, f)
+    }
+
+    #[inline]
+    fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
+        where P: FnMut(&Self::Item) -> bool
+    {
+        self.iter.rfind(predicate)
+    }
+
+    #[inline]
+    fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
+        P: FnMut(Self::Item) -> bool
+    {
+        self.iter.position(predicate)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> DoubleEndedIterator for Rev<I> where I: DoubleEndedIterator {
+    #[inline]
+    fn next_back(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next() }
+
+    #[inline]
+    fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item> { self.iter.nth(n) }
+
+    fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.iter.try_fold(init, f)
+    }
+
+    fn rfold<Acc, F>(self, init: Acc, f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.iter.fold(init, f)
+    }
+
+    fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
+        where P: FnMut(&Self::Item) -> bool
+    {
+        self.iter.find(predicate)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> ExactSizeIterator for Rev<I>
+    where I: ExactSizeIterator + DoubleEndedIterator
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Rev<I>
+    where I: FusedIterator + DoubleEndedIterator {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<I> TrustedLen for Rev<I>
+    where I: TrustedLen + DoubleEndedIterator {}
+
+/// An iterator that copies the elements of an underlying iterator.
+///
+/// This `struct` is created by the [`copied`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`copied`]: trait.Iterator.html#method.copied
+/// [`Iterator`]: trait.Iterator.html
+#[unstable(feature = "iter_copied", issue = "57127")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[derive(Clone, Debug)]
+pub struct Copied<I> {
+    it: I,
+}
+impl<I> Copied<I> {
+    pub(super) fn new(it: I) -> Copied<I> {
+        Copied { it }
+    }
+}
+
+#[unstable(feature = "iter_copied", issue = "57127")]
+impl<'a, I, T: 'a> Iterator for Copied<I>
+    where I: Iterator<Item=&'a T>, T: Copy
+{
+    type Item = T;
+
+    fn next(&mut self) -> Option<T> {
+        self.it.next().copied()
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.it.size_hint()
+    }
+
+    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.it.try_fold(init, move |acc, &elt| f(acc, elt))
+    }
+
+    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.it.fold(init, move |acc, &elt| f(acc, elt))
+    }
+}
+
+#[unstable(feature = "iter_copied", issue = "57127")]
+impl<'a, I, T: 'a> DoubleEndedIterator for Copied<I>
+    where I: DoubleEndedIterator<Item=&'a T>, T: Copy
+{
+    fn next_back(&mut self) -> Option<T> {
+        self.it.next_back().copied()
+    }
+
+    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.it.try_rfold(init, move |acc, &elt| f(acc, elt))
+    }
+
+    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.it.rfold(init, move |acc, &elt| f(acc, elt))
+    }
+}
+
+#[unstable(feature = "iter_copied", issue = "57127")]
+impl<'a, I, T: 'a> ExactSizeIterator for Copied<I>
+    where I: ExactSizeIterator<Item=&'a T>, T: Copy
+{
+    fn len(&self) -> usize {
+        self.it.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.it.is_empty()
+    }
+}
+
+#[unstable(feature = "iter_copied", issue = "57127")]
+impl<'a, I, T: 'a> FusedIterator for Copied<I>
+    where I: FusedIterator<Item=&'a T>, T: Copy
+{}
+
+#[doc(hidden)]
+unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Copied<I>
+    where I: TrustedRandomAccess<Item=&'a T>, T: Copy
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
+        *self.it.get_unchecked(i)
+    }
+
+    #[inline]
+    fn may_have_side_effect() -> bool {
+        I::may_have_side_effect()
+    }
+}
+
+#[unstable(feature = "iter_copied", issue = "57127")]
+unsafe impl<'a, I, T: 'a> TrustedLen for Copied<I>
+    where I: TrustedLen<Item=&'a T>,
+          T: Copy
+{}
+
+/// An iterator that clones the elements of an underlying iterator.
+///
+/// This `struct` is created by the [`cloned`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`cloned`]: trait.Iterator.html#method.cloned
+/// [`Iterator`]: trait.Iterator.html
+#[stable(feature = "iter_cloned", since = "1.1.0")]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[derive(Clone, Debug)]
+pub struct Cloned<I> {
+    it: I,
+}
+impl<I> Cloned<I> {
+    pub(super) fn new(it: I) -> Cloned<I> {
+        Cloned { it }
+    }
+}
+
+#[stable(feature = "iter_cloned", since = "1.1.0")]
+impl<'a, I, T: 'a> Iterator for Cloned<I>
+    where I: Iterator<Item=&'a T>, T: Clone
+{
+    type Item = T;
+
+    fn next(&mut self) -> Option<T> {
+        self.it.next().cloned()
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.it.size_hint()
+    }
+
+    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.it.try_fold(init, move |acc, elt| f(acc, elt.clone()))
+    }
+
+    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.it.fold(init, move |acc, elt| f(acc, elt.clone()))
+    }
+}
+
+#[stable(feature = "iter_cloned", since = "1.1.0")]
+impl<'a, I, T: 'a> DoubleEndedIterator for Cloned<I>
+    where I: DoubleEndedIterator<Item=&'a T>, T: Clone
+{
+    fn next_back(&mut self) -> Option<T> {
+        self.it.next_back().cloned()
+    }
+
+    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        self.it.try_rfold(init, move |acc, elt| f(acc, elt.clone()))
+    }
+
+    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
+        where F: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.it.rfold(init, move |acc, elt| f(acc, elt.clone()))
+    }
+}
+
+#[stable(feature = "iter_cloned", since = "1.1.0")]
+impl<'a, I, T: 'a> ExactSizeIterator for Cloned<I>
+    where I: ExactSizeIterator<Item=&'a T>, T: Clone
+{
+    fn len(&self) -> usize {
+        self.it.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.it.is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<'a, I, T: 'a> FusedIterator for Cloned<I>
+    where I: FusedIterator<Item=&'a T>, T: Clone
+{}
+
+#[doc(hidden)]
+unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
+    where I: TrustedRandomAccess<Item=&'a T>, T: Clone
+{
+    default unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
+        self.it.get_unchecked(i).clone()
+    }
+
+    #[inline]
+    default fn may_have_side_effect() -> bool { true }
+}
+
+#[doc(hidden)]
+unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
+    where I: TrustedRandomAccess<Item=&'a T>, T: Copy
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
+        *self.it.get_unchecked(i)
+    }
+
+    #[inline]
+    fn may_have_side_effect() -> bool {
+        I::may_have_side_effect()
+    }
+}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<'a, I, T: 'a> TrustedLen for Cloned<I>
+    where I: TrustedLen<Item=&'a T>,
+          T: Clone
+{}
+
+/// An iterator that repeats endlessly.
+///
+/// This `struct` is created by the [`cycle`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`cycle`]: trait.Iterator.html#method.cycle
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Cycle<I> {
+    orig: I,
+    iter: I,
+}
+impl<I: Clone> Cycle<I> {
+    pub(super) fn new(iter: I) -> Cycle<I> {
+        Cycle { orig: iter.clone(), iter }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Cycle<I> where I: Clone + Iterator {
+    type Item = <I as Iterator>::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<<I as Iterator>::Item> {
+        match self.iter.next() {
+            None => { self.iter = self.orig.clone(); self.iter.next() }
+            y => y
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        // the cycle iterator is either empty or infinite
+        match self.orig.size_hint() {
+            sz @ (0, Some(0)) => sz,
+            (0, _) => (0, None),
+            _ => (usize::MAX, None)
+        }
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Cycle<I> where I: Clone + Iterator {}
+
+/// An iterator for stepping iterators by a custom amount.
+///
+/// This `struct` is created by the [`step_by`] method on [`Iterator`]. See
+/// its documentation for more.
+///
+/// [`step_by`]: trait.Iterator.html#method.step_by
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "iterator_step_by", since = "1.28.0")]
+#[derive(Clone, Debug)]
+pub struct StepBy<I> {
+    iter: I,
+    step: usize,
+    first_take: bool,
+}
+impl<I> StepBy<I> {
+    pub(super) fn new(iter: I, step: usize) -> StepBy<I> {
+        assert!(step != 0);
+        StepBy { iter, step: step - 1, first_take: true }
+    }
+}
+
+#[stable(feature = "iterator_step_by", since = "1.28.0")]
+impl<I> Iterator for StepBy<I> where I: Iterator {
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.first_take {
+            self.first_take = false;
+            self.iter.next()
+        } else {
+            self.iter.nth(self.step)
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let inner_hint = self.iter.size_hint();
+
+        if self.first_take {
+            let f = |n| if n == 0 { 0 } else { 1 + (n-1)/(self.step+1) };
+            (f(inner_hint.0), inner_hint.1.map(f))
+        } else {
+            let f = |n| n / (self.step+1);
+            (f(inner_hint.0), inner_hint.1.map(f))
+        }
+    }
+
+    #[inline]
+    fn nth(&mut self, mut n: usize) -> Option<Self::Item> {
+        if self.first_take {
+            self.first_take = false;
+            let first = self.iter.next();
+            if n == 0 {
+                return first;
+            }
+            n -= 1;
+        }
+        // n and self.step are indices, we need to add 1 to get the amount of elements
+        // When calling `.nth`, we need to subtract 1 again to convert back to an index
+        // step + 1 can't overflow because `.step_by` sets `self.step` to `step - 1`
+        let mut step = self.step + 1;
+        // n + 1 could overflow
+        // thus, if n is usize::MAX, instead of adding one, we call .nth(step)
+        if n == usize::MAX {
+            self.iter.nth(step - 1);
+        } else {
+            n += 1;
+        }
+
+        // overflow handling
+        loop {
+            let mul = n.checked_mul(step);
+            if unsafe { intrinsics::likely(mul.is_some()) } {
+                return self.iter.nth(mul.unwrap() - 1);
+            }
+            let div_n = usize::MAX / n;
+            let div_step = usize::MAX / step;
+            let nth_n = div_n * n;
+            let nth_step = div_step * step;
+            let nth = if nth_n > nth_step {
+                step -= div_n;
+                nth_n
+            } else {
+                n -= div_step;
+                nth_step
+            };
+            self.iter.nth(nth - 1);
+        }
+    }
+}
+
+// StepBy can only make the iterator shorter, so the len will still fit.
+#[stable(feature = "iterator_step_by", since = "1.28.0")]
+impl<I> ExactSizeIterator for StepBy<I> where I: ExactSizeIterator {}
+
+/// An iterator that maps the values of `iter` with `f`.
+///
+/// This `struct` is created by the [`map`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`map`]: trait.Iterator.html#method.map
+/// [`Iterator`]: trait.Iterator.html
+///
+/// # Notes about side effects
+///
+/// The [`map`] iterator implements [`DoubleEndedIterator`], meaning that
+/// you can also [`map`] backwards:
+///
+/// ```rust
+/// let v: Vec<i32> = vec![1, 2, 3].into_iter().map(|x| x + 1).rev().collect();
+///
+/// assert_eq!(v, [4, 3, 2]);
+/// ```
+///
+/// [`DoubleEndedIterator`]: trait.DoubleEndedIterator.html
+///
+/// But if your closure has state, iterating backwards may act in a way you do
+/// not expect. Let's go through an example. First, in the forward direction:
+///
+/// ```rust
+/// let mut c = 0;
+///
+/// for pair in vec!['a', 'b', 'c'].into_iter()
+///                                .map(|letter| { c += 1; (letter, c) }) {
+///     println!("{:?}", pair);
+/// }
+/// ```
+///
+/// This will print "('a', 1), ('b', 2), ('c', 3)".
+///
+/// Now consider this twist where we add a call to `rev`. This version will
+/// print `('c', 1), ('b', 2), ('a', 3)`. Note that the letters are reversed,
+/// but the values of the counter still go in order. This is because `map()` is
+/// still being called lazily on each item, but we are popping items off the
+/// back of the vector now, instead of shifting them from the front.
+///
+/// ```rust
+/// let mut c = 0;
+///
+/// for pair in vec!['a', 'b', 'c'].into_iter()
+///                                .map(|letter| { c += 1; (letter, c) })
+///                                .rev() {
+///     println!("{:?}", pair);
+/// }
+/// ```
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct Map<I, F> {
+    iter: I,
+    f: F,
+}
+impl<I, F> Map<I, F> {
+    pub(super) fn new(iter: I, f: F) -> Map<I, F> {
+        Map { iter, f }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, F> fmt::Debug for Map<I, F> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Map")
+            .field("iter", &self.iter)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I: Iterator, F> Iterator for Map<I, F> where F: FnMut(I::Item) -> B {
+    type Item = B;
+
+    #[inline]
+    fn next(&mut self) -> Option<B> {
+        self.iter.next().map(&mut self.f)
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    fn try_fold<Acc, G, R>(&mut self, init: Acc, mut g: G) -> R where
+        Self: Sized, G: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_fold(init, move |acc, elt| g(acc, f(elt)))
+    }
+
+    fn fold<Acc, G>(self, init: Acc, mut g: G) -> Acc
+        where G: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.fold(init, move |acc, elt| g(acc, f(elt)))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for Map<I, F> where
+    F: FnMut(I::Item) -> B,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<B> {
+        self.iter.next_back().map(&mut self.f)
+    }
+
+    fn try_rfold<Acc, G, R>(&mut self, init: Acc, mut g: G) -> R where
+        Self: Sized, G: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_rfold(init, move |acc, elt| g(acc, f(elt)))
+    }
+
+    fn rfold<Acc, G>(self, init: Acc, mut g: G) -> Acc
+        where G: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.rfold(init, move |acc, elt| g(acc, f(elt)))
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I: ExactSizeIterator, F> ExactSizeIterator for Map<I, F>
+    where F: FnMut(I::Item) -> B
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<B, I: FusedIterator, F> FusedIterator for Map<I, F>
+    where F: FnMut(I::Item) -> B {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<B, I, F> TrustedLen for Map<I, F>
+    where I: TrustedLen,
+          F: FnMut(I::Item) -> B {}
+
+#[doc(hidden)]
+unsafe impl<B, I, F> TrustedRandomAccess for Map<I, F>
+    where I: TrustedRandomAccess,
+          F: FnMut(I::Item) -> B,
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
+        (self.f)(self.iter.get_unchecked(i))
+    }
+    #[inline]
+    fn may_have_side_effect() -> bool { true }
+}
+
+/// An iterator that filters the elements of `iter` with `predicate`.
+///
+/// This `struct` is created by the [`filter`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`filter`]: trait.Iterator.html#method.filter
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct Filter<I, P> {
+    iter: I,
+    predicate: P,
+}
+impl<I, P> Filter<I, P> {
+    pub(super) fn new(iter: I, predicate: P) -> Filter<I, P> {
+        Filter { iter, predicate }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, P> fmt::Debug for Filter<I, P> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Filter")
+            .field("iter", &self.iter)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, P> Iterator for Filter<I, P> where P: FnMut(&I::Item) -> bool {
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        for x in &mut self.iter {
+            if (self.predicate)(&x) {
+                return Some(x);
+            }
+        }
+        None
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (_, upper) = self.iter.size_hint();
+        (0, upper) // can't know a lower bound, due to the predicate
+    }
+
+    // this special case allows the compiler to make `.filter(_).count()`
+    // branchless. Barring perfect branch prediction (which is unattainable in
+    // the general case), this will be much faster in >90% of cases (containing
+    // virtually all real workloads) and only a tiny bit slower in the rest.
+    //
+    // Having this specialization thus allows us to write `.filter(p).count()`
+    // where we would otherwise write `.map(|x| p(x) as usize).sum()`, which is
+    // less readable and also less backwards-compatible to Rust before 1.10.
+    //
+    // Using the branchless version will also simplify the LLVM byte code, thus
+    // leaving more budget for LLVM optimizations.
+    #[inline]
+    fn count(mut self) -> usize {
+        let mut count = 0;
+        for x in &mut self.iter {
+            count += (self.predicate)(&x) as usize;
+        }
+        count
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let predicate = &mut self.predicate;
+        self.iter.try_fold(init, move |acc, item| if predicate(&item) {
+            fold(acc, item)
+        } else {
+            Try::from_ok(acc)
+        })
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut predicate = self.predicate;
+        self.iter.fold(init, move |acc, item| if predicate(&item) {
+            fold(acc, item)
+        } else {
+            acc
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: DoubleEndedIterator, P> DoubleEndedIterator for Filter<I, P>
+    where P: FnMut(&I::Item) -> bool,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<I::Item> {
+        for x in self.iter.by_ref().rev() {
+            if (self.predicate)(&x) {
+                return Some(x);
+            }
+        }
+        None
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let predicate = &mut self.predicate;
+        self.iter.try_rfold(init, move |acc, item| if predicate(&item) {
+            fold(acc, item)
+        } else {
+            Try::from_ok(acc)
+        })
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut predicate = self.predicate;
+        self.iter.rfold(init, move |acc, item| if predicate(&item) {
+            fold(acc, item)
+        } else {
+            acc
+        })
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator, P> FusedIterator for Filter<I, P>
+    where P: FnMut(&I::Item) -> bool {}
+
+/// An iterator that uses `f` to both filter and map elements from `iter`.
+///
+/// This `struct` is created by the [`filter_map`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`filter_map`]: trait.Iterator.html#method.filter_map
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct FilterMap<I, F> {
+    iter: I,
+    f: F,
+}
+impl<I, F> FilterMap<I, F> {
+    pub(super) fn new(iter: I, f: F) -> FilterMap<I, F> {
+        FilterMap { iter, f }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, F> fmt::Debug for FilterMap<I, F> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("FilterMap")
+            .field("iter", &self.iter)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I: Iterator, F> Iterator for FilterMap<I, F>
+    where F: FnMut(I::Item) -> Option<B>,
+{
+    type Item = B;
+
+    #[inline]
+    fn next(&mut self) -> Option<B> {
+        for x in self.iter.by_ref() {
+            if let Some(y) = (self.f)(x) {
+                return Some(y);
+            }
+        }
+        None
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (_, upper) = self.iter.size_hint();
+        (0, upper) // can't know a lower bound, due to the predicate
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_fold(init, move |acc, item| match f(item) {
+            Some(x) => fold(acc, x),
+            None => Try::from_ok(acc),
+        })
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.fold(init, move |acc, item| match f(item) {
+            Some(x) => fold(acc, x),
+            None => acc,
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for FilterMap<I, F>
+    where F: FnMut(I::Item) -> Option<B>,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<B> {
+        for x in self.iter.by_ref().rev() {
+            if let Some(y) = (self.f)(x) {
+                return Some(y);
+            }
+        }
+        None
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_rfold(init, move |acc, item| match f(item) {
+            Some(x) => fold(acc, x),
+            None => Try::from_ok(acc),
+        })
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.rfold(init, move |acc, item| match f(item) {
+            Some(x) => fold(acc, x),
+            None => acc,
+        })
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<B, I: FusedIterator, F> FusedIterator for FilterMap<I, F>
+    where F: FnMut(I::Item) -> Option<B> {}
+
+/// An iterator that yields the current count and the element during iteration.
+///
+/// This `struct` is created by the [`enumerate`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`enumerate`]: trait.Iterator.html#method.enumerate
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Enumerate<I> {
+    iter: I,
+    count: usize,
+}
+impl<I> Enumerate<I> {
+    pub(super) fn new(iter: I) -> Enumerate<I> {
+        Enumerate { iter, count: 0 }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Enumerate<I> where I: Iterator {
+    type Item = (usize, <I as Iterator>::Item);
+
+    /// # Overflow Behavior
+    ///
+    /// The method does no guarding against overflows, so enumerating more than
+    /// `usize::MAX` elements either produces the wrong result or panics. If
+    /// debug assertions are enabled, a panic is guaranteed.
+    ///
+    /// # Panics
+    ///
+    /// Might panic if the index of the element overflows a `usize`.
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
+        self.iter.next().map(|a| {
+            let ret = (self.count, a);
+            // Possible undefined overflow.
+            self.count += 1;
+            ret
+        })
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn nth(&mut self, n: usize) -> Option<(usize, I::Item)> {
+        self.iter.nth(n).map(|a| {
+            let i = self.count + n;
+            self.count = i + 1;
+            (i, a)
+        })
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.iter.count()
+    }
+
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let count = &mut self.count;
+        self.iter.try_fold(init, move |acc, item| {
+            let acc = fold(acc, (*count, item));
+            *count += 1;
+            acc
+        })
+    }
+
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut count = self.count;
+        self.iter.fold(init, move |acc, item| {
+            let acc = fold(acc, (count, item));
+            count += 1;
+            acc
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> DoubleEndedIterator for Enumerate<I> where
+    I: ExactSizeIterator + DoubleEndedIterator
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
+        self.iter.next_back().map(|a| {
+            let len = self.iter.len();
+            // Can safely add, `ExactSizeIterator` promises that the number of
+            // elements fits into a `usize`.
+            (self.count + len, a)
+        })
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        // Can safely add and subtract the count, as `ExactSizeIterator` promises
+        // that the number of elements fits into a `usize`.
+        let mut count = self.count + self.iter.len();
+        self.iter.try_rfold(init, move |acc, item| {
+            count -= 1;
+            fold(acc, (count, item))
+        })
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        // Can safely add and subtract the count, as `ExactSizeIterator` promises
+        // that the number of elements fits into a `usize`.
+        let mut count = self.count + self.iter.len();
+        self.iter.rfold(init, move |acc, item| {
+            count -= 1;
+            fold(acc, (count, item))
+        })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> ExactSizeIterator for Enumerate<I> where I: ExactSizeIterator {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+#[doc(hidden)]
+unsafe impl<I> TrustedRandomAccess for Enumerate<I>
+    where I: TrustedRandomAccess
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> (usize, I::Item) {
+        (self.count + i, self.iter.get_unchecked(i))
+    }
+
+    fn may_have_side_effect() -> bool {
+        I::may_have_side_effect()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Enumerate<I> where I: FusedIterator {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<I> TrustedLen for Enumerate<I>
+    where I: TrustedLen,
+{}
+
+
+/// An iterator with a `peek()` that returns an optional reference to the next
+/// element.
+///
+/// This `struct` is created by the [`peekable`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`peekable`]: trait.Iterator.html#method.peekable
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Peekable<I: Iterator> {
+    iter: I,
+    /// Remember a peeked value, even if it was None.
+    peeked: Option<Option<I::Item>>,
+}
+impl<I: Iterator> Peekable<I> {
+    pub(super) fn new(iter: I) -> Peekable<I> {
+        Peekable { iter, peeked: None }
+    }
+}
+
+// Peekable must remember if a None has been seen in the `.peek()` method.
+// It ensures that `.peek(); .peek();` or `.peek(); .next();` only advances the
+// underlying iterator at most once. This does not by itself make the iterator
+// fused.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator> Iterator for Peekable<I> {
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        match self.peeked.take() {
+            Some(v) => v,
+            None => self.iter.next(),
+        }
+    }
+
+    #[inline]
+    #[rustc_inherit_overflow_checks]
+    fn count(mut self) -> usize {
+        match self.peeked.take() {
+            Some(None) => 0,
+            Some(Some(_)) => 1 + self.iter.count(),
+            None => self.iter.count(),
+        }
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<I::Item> {
+        match self.peeked.take() {
+            Some(None) => None,
+            Some(v @ Some(_)) if n == 0 => v,
+            Some(Some(_)) => self.iter.nth(n - 1),
+            None => self.iter.nth(n),
+        }
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<I::Item> {
+        let peek_opt = match self.peeked.take() {
+            Some(None) => return None,
+            Some(v) => v,
+            None => None,
+        };
+        self.iter.last().or(peek_opt)
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let peek_len = match self.peeked {
+            Some(None) => return (0, Some(0)),
+            Some(Some(_)) => 1,
+            None => 0,
+        };
+        let (lo, hi) = self.iter.size_hint();
+        let lo = lo.saturating_add(peek_len);
+        let hi = hi.and_then(|x| x.checked_add(peek_len));
+        (lo, hi)
+    }
+
+    #[inline]
+    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
+        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
+    {
+        let acc = match self.peeked.take() {
+            Some(None) => return Try::from_ok(init),
+            Some(Some(v)) => f(init, v)?,
+            None => init,
+        };
+        self.iter.try_fold(acc, f)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let acc = match self.peeked {
+            Some(None) => return init,
+            Some(Some(v)) => fold(init, v),
+            None => init,
+        };
+        self.iter.fold(acc, fold)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: ExactSizeIterator> ExactSizeIterator for Peekable<I> {}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator> FusedIterator for Peekable<I> {}
+
+impl<I: Iterator> Peekable<I> {
+    /// Returns a reference to the next() value without advancing the iterator.
+    ///
+    /// Like [`next`], if there is a value, it is wrapped in a `Some(T)`.
+    /// But if the iteration is over, `None` is returned.
+    ///
+    /// [`next`]: trait.Iterator.html#tymethod.next
+    ///
+    /// Because `peek()` returns a reference, and many iterators iterate over
+    /// references, there can be a possibly confusing situation where the
+    /// return value is a double reference. You can see this effect in the
+    /// examples below.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let xs = [1, 2, 3];
+    ///
+    /// let mut iter = xs.iter().peekable();
+    ///
+    /// // peek() lets us see into the future
+    /// assert_eq!(iter.peek(), Some(&&1));
+    /// assert_eq!(iter.next(), Some(&1));
+    ///
+    /// assert_eq!(iter.next(), Some(&2));
+    ///
+    /// // The iterator does not advance even if we `peek` multiple times
+    /// assert_eq!(iter.peek(), Some(&&3));
+    /// assert_eq!(iter.peek(), Some(&&3));
+    ///
+    /// assert_eq!(iter.next(), Some(&3));
+    ///
+    /// // After the iterator is finished, so is `peek()`
+    /// assert_eq!(iter.peek(), None);
+    /// assert_eq!(iter.next(), None);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn peek(&mut self) -> Option<&I::Item> {
+        let iter = &mut self.iter;
+        self.peeked.get_or_insert_with(|| iter.next()).as_ref()
+    }
+}
+
+/// An iterator that rejects elements while `predicate` is true.
+///
+/// This `struct` is created by the [`skip_while`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`skip_while`]: trait.Iterator.html#method.skip_while
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct SkipWhile<I, P> {
+    iter: I,
+    flag: bool,
+    predicate: P,
+}
+impl<I, P> SkipWhile<I, P> {
+    pub(super) fn new(iter: I, predicate: P) -> SkipWhile<I, P> {
+        SkipWhile { iter, flag: false, predicate }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, P> fmt::Debug for SkipWhile<I, P> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("SkipWhile")
+            .field("iter", &self.iter)
+            .field("flag", &self.flag)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, P> Iterator for SkipWhile<I, P>
+    where P: FnMut(&I::Item) -> bool
+{
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        let flag = &mut self.flag;
+        let pred = &mut self.predicate;
+        self.iter.find(move |x| {
+            if *flag || !pred(x) {
+                *flag = true;
+                true
+            } else {
+                false
+            }
+        })
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (_, upper) = self.iter.size_hint();
+        (0, upper) // can't know a lower bound, due to the predicate
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if !self.flag {
+            match self.next() {
+                Some(v) => init = fold(init, v)?,
+                None => return Try::from_ok(init),
+            }
+        }
+        self.iter.try_fold(init, fold)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(mut self, mut init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        if !self.flag {
+            match self.next() {
+                Some(v) => init = fold(init, v),
+                None => return init,
+            }
+        }
+        self.iter.fold(init, fold)
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I, P> FusedIterator for SkipWhile<I, P>
+    where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
+
+/// An iterator that only accepts elements while `predicate` is true.
+///
+/// This `struct` is created by the [`take_while`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`take_while`]: trait.Iterator.html#method.take_while
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct TakeWhile<I, P> {
+    iter: I,
+    flag: bool,
+    predicate: P,
+}
+impl<I, P> TakeWhile<I, P> {
+    pub(super) fn new(iter: I, predicate: P) -> TakeWhile<I, P> {
+        TakeWhile { iter, flag: false, predicate }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, P> fmt::Debug for TakeWhile<I, P> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("TakeWhile")
+            .field("iter", &self.iter)
+            .field("flag", &self.flag)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, P> Iterator for TakeWhile<I, P>
+    where P: FnMut(&I::Item) -> bool
+{
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        if self.flag {
+            None
+        } else {
+            self.iter.next().and_then(|x| {
+                if (self.predicate)(&x) {
+                    Some(x)
+                } else {
+                    self.flag = true;
+                    None
+                }
+            })
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.flag {
+            (0, Some(0))
+        } else {
+            let (_, upper) = self.iter.size_hint();
+            (0, upper) // can't know a lower bound, due to the predicate
+        }
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if self.flag {
+            Try::from_ok(init)
+        } else {
+            let flag = &mut self.flag;
+            let p = &mut self.predicate;
+            self.iter.try_fold(init, move |acc, x|{
+                if p(&x) {
+                    LoopState::from_try(fold(acc, x))
+                } else {
+                    *flag = true;
+                    LoopState::Break(Try::from_ok(acc))
+                }
+            }).into_try()
+        }
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I, P> FusedIterator for TakeWhile<I, P>
+    where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
+
+/// An iterator that skips over `n` elements of `iter`.
+///
+/// This `struct` is created by the [`skip`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`skip`]: trait.Iterator.html#method.skip
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Skip<I> {
+    iter: I,
+    n: usize
+}
+impl<I> Skip<I> {
+    pub(super) fn new(iter: I, n: usize) -> Skip<I> {
+        Skip { iter, n }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Skip<I> where I: Iterator {
+    type Item = <I as Iterator>::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        if self.n == 0 {
+            self.iter.next()
+        } else {
+            let old_n = self.n;
+            self.n = 0;
+            self.iter.nth(old_n)
+        }
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<I::Item> {
+        // Can't just add n + self.n due to overflow.
+        if self.n == 0 {
+            self.iter.nth(n)
+        } else {
+            let to_skip = self.n;
+            self.n = 0;
+            // nth(n) skips n+1
+            if self.iter.nth(to_skip-1).is_none() {
+                return None;
+            }
+            self.iter.nth(n)
+        }
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.iter.count().saturating_sub(self.n)
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<I::Item> {
+        if self.n == 0 {
+            self.iter.last()
+        } else {
+            let next = self.next();
+            if next.is_some() {
+                // recurse. n should be 0.
+                self.last().or(next)
+            } else {
+                None
+            }
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (lower, upper) = self.iter.size_hint();
+
+        let lower = lower.saturating_sub(self.n);
+        let upper = upper.map(|x| x.saturating_sub(self.n));
+
+        (lower, upper)
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let n = self.n;
+        self.n = 0;
+        if n > 0 {
+            // nth(n) skips n+1
+            if self.iter.nth(n - 1).is_none() {
+                return Try::from_ok(init);
+            }
+        }
+        self.iter.try_fold(init, fold)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        if self.n > 0 {
+            // nth(n) skips n+1
+            if self.iter.nth(self.n - 1).is_none() {
+                return init;
+            }
+        }
+        self.iter.fold(init, fold)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> ExactSizeIterator for Skip<I> where I: ExactSizeIterator {}
+
+#[stable(feature = "double_ended_skip_iterator", since = "1.9.0")]
+impl<I> DoubleEndedIterator for Skip<I> where I: DoubleEndedIterator + ExactSizeIterator {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        if self.len() > 0 {
+            self.iter.next_back()
+        } else {
+            None
+        }
+    }
+
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let mut n = self.len();
+        if n == 0 {
+            Try::from_ok(init)
+        } else {
+            self.iter.try_rfold(init, move |acc, x| {
+                n -= 1;
+                let r = fold(acc, x);
+                if n == 0 { LoopState::Break(r) }
+                else { LoopState::from_try(r) }
+            }).into_try()
+        }
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Skip<I> where I: FusedIterator {}
+
+/// An iterator that only iterates over the first `n` iterations of `iter`.
+///
+/// This `struct` is created by the [`take`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`take`]: trait.Iterator.html#method.take
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Take<I> {
+    pub(super) iter: I,
+    pub(super) n: usize
+}
+impl<I> Take<I> {
+    pub(super) fn new(iter: I, n: usize) -> Take<I> {
+        Take { iter, n }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Take<I> where I: Iterator{
+    type Item = <I as Iterator>::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<<I as Iterator>::Item> {
+        if self.n != 0 {
+            self.n -= 1;
+            self.iter.next()
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<I::Item> {
+        if self.n > n {
+            self.n -= n + 1;
+            self.iter.nth(n)
+        } else {
+            if self.n > 0 {
+                self.iter.nth(self.n - 1);
+                self.n = 0;
+            }
+            None
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.n == 0 {
+            return (0, Some(0));
+        }
+
+        let (lower, upper) = self.iter.size_hint();
+
+        let lower = cmp::min(lower, self.n);
+
+        let upper = match upper {
+            Some(x) if x < self.n => Some(x),
+            _ => Some(self.n)
+        };
+
+        (lower, upper)
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if self.n == 0 {
+            Try::from_ok(init)
+        } else {
+            let n = &mut self.n;
+            self.iter.try_fold(init, move |acc, x| {
+                *n -= 1;
+                let r = fold(acc, x);
+                if *n == 0 { LoopState::Break(r) }
+                else { LoopState::from_try(r) }
+            }).into_try()
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> ExactSizeIterator for Take<I> where I: ExactSizeIterator {}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Take<I> where I: FusedIterator {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<I: TrustedLen> TrustedLen for Take<I> {}
+
+/// An iterator to maintain state while iterating another iterator.
+///
+/// This `struct` is created by the [`scan`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`scan`]: trait.Iterator.html#method.scan
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct Scan<I, St, F> {
+    iter: I,
+    f: F,
+    state: St,
+}
+impl<I, St, F> Scan<I, St, F> {
+    pub(super) fn new(iter: I, state: St, f: F) -> Scan<I, St, F> {
+        Scan { iter, state, f }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, St: fmt::Debug, F> fmt::Debug for Scan<I, St, F> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Scan")
+            .field("iter", &self.iter)
+            .field("state", &self.state)
+            .finish()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B, I, St, F> Iterator for Scan<I, St, F> where
+    I: Iterator,
+    F: FnMut(&mut St, I::Item) -> Option<B>,
+{
+    type Item = B;
+
+    #[inline]
+    fn next(&mut self) -> Option<B> {
+        self.iter.next().and_then(|a| (self.f)(&mut self.state, a))
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (_, upper) = self.iter.size_hint();
+        (0, upper) // can't know a lower bound, due to the scan function
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let state = &mut self.state;
+        let f = &mut self.f;
+        self.iter.try_fold(init, move |acc, x| {
+            match f(state, x) {
+                None => LoopState::Break(Try::from_ok(acc)),
+                Some(x) => LoopState::from_try(fold(acc, x)),
+            }
+        }).into_try()
+    }
+}
+
+/// An iterator that yields `None` forever after the underlying iterator
+/// yields `None` once.
+///
+/// This `struct` is created by the [`fuse`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`fuse`]: trait.Iterator.html#method.fuse
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Fuse<I> {
+    iter: I,
+    done: bool
+}
+impl<I> Fuse<I> {
+    pub(super) fn new(iter: I) -> Fuse<I> {
+        Fuse { iter, done: false }
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> FusedIterator for Fuse<I> where I: Iterator {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> Iterator for Fuse<I> where I: Iterator {
+    type Item = <I as Iterator>::Item;
+
+    #[inline]
+    default fn next(&mut self) -> Option<<I as Iterator>::Item> {
+        if self.done {
+            None
+        } else {
+            let next = self.iter.next();
+            self.done = next.is_none();
+            next
+        }
+    }
+
+    #[inline]
+    default fn nth(&mut self, n: usize) -> Option<I::Item> {
+        if self.done {
+            None
+        } else {
+            let nth = self.iter.nth(n);
+            self.done = nth.is_none();
+            nth
+        }
+    }
+
+    #[inline]
+    default fn last(self) -> Option<I::Item> {
+        if self.done {
+            None
+        } else {
+            self.iter.last()
+        }
+    }
+
+    #[inline]
+    default fn count(self) -> usize {
+        if self.done {
+            0
+        } else {
+            self.iter.count()
+        }
+    }
+
+    #[inline]
+    default fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.done {
+            (0, Some(0))
+        } else {
+            self.iter.size_hint()
+        }
+    }
+
+    #[inline]
+    default fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if self.done {
+            Try::from_ok(init)
+        } else {
+            let acc = self.iter.try_fold(init, fold)?;
+            self.done = true;
+            Try::from_ok(acc)
+        }
+    }
+
+    #[inline]
+    default fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        if self.done {
+            init
+        } else {
+            self.iter.fold(init, fold)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> DoubleEndedIterator for Fuse<I> where I: DoubleEndedIterator {
+    #[inline]
+    default fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
+        if self.done {
+            None
+        } else {
+            let next = self.iter.next_back();
+            self.done = next.is_none();
+            next
+        }
+    }
+
+    #[inline]
+    default fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        if self.done {
+            Try::from_ok(init)
+        } else {
+            let acc = self.iter.try_rfold(init, fold)?;
+            self.done = true;
+            Try::from_ok(acc)
+        }
+    }
+
+    #[inline]
+    default fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        if self.done {
+            init
+        } else {
+            self.iter.rfold(init, fold)
+        }
+    }
+}
+
+unsafe impl<I> TrustedRandomAccess for Fuse<I>
+    where I: TrustedRandomAccess,
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> I::Item {
+        self.iter.get_unchecked(i)
+    }
+
+    fn may_have_side_effect() -> bool {
+        I::may_have_side_effect()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> Iterator for Fuse<I> where I: FusedIterator {
+    #[inline]
+    fn next(&mut self) -> Option<<I as Iterator>::Item> {
+        self.iter.next()
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<I::Item> {
+        self.iter.nth(n)
+    }
+
+    #[inline]
+    fn last(self) -> Option<I::Item> {
+        self.iter.last()
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.iter.count()
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.iter.try_fold(init, fold)
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.iter.fold(init, fold)
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I> DoubleEndedIterator for Fuse<I>
+    where I: DoubleEndedIterator + FusedIterator
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
+        self.iter.next_back()
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        self.iter.try_rfold(init, fold)
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.iter.rfold(init, fold)
+    }
+}
+
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I> ExactSizeIterator for Fuse<I> where I: ExactSizeIterator {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+/// An iterator that calls a function with a reference to each element before
+/// yielding it.
+///
+/// This `struct` is created by the [`inspect`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`inspect`]: trait.Iterator.html#method.inspect
+/// [`Iterator`]: trait.Iterator.html
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Clone)]
+pub struct Inspect<I, F> {
+    iter: I,
+    f: F,
+}
+impl<I, F> Inspect<I, F> {
+    pub(super) fn new(iter: I, f: F) -> Inspect<I, F> {
+        Inspect { iter, f }
+    }
+}
+
+#[stable(feature = "core_impl_debug", since = "1.9.0")]
+impl<I: fmt::Debug, F> fmt::Debug for Inspect<I, F> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Inspect")
+            .field("iter", &self.iter)
+            .finish()
+    }
+}
+
+impl<I: Iterator, F> Inspect<I, F> where F: FnMut(&I::Item) {
+    #[inline]
+    fn do_inspect(&mut self, elt: Option<I::Item>) -> Option<I::Item> {
+        if let Some(ref a) = elt {
+            (self.f)(a);
+        }
+
+        elt
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, F> Iterator for Inspect<I, F> where F: FnMut(&I::Item) {
+    type Item = I::Item;
+
+    #[inline]
+    fn next(&mut self) -> Option<I::Item> {
+        let next = self.iter.next();
+        self.do_inspect(next)
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    #[inline]
+    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_fold(init, move |acc, item| { f(&item); fold(acc, item) })
+    }
+
+    #[inline]
+    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.fold(init, move |acc, item| { f(&item); fold(acc, item) })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: DoubleEndedIterator, F> DoubleEndedIterator for Inspect<I, F>
+    where F: FnMut(&I::Item),
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<I::Item> {
+        let next = self.iter.next_back();
+        self.do_inspect(next)
+    }
+
+    #[inline]
+    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
+        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+    {
+        let f = &mut self.f;
+        self.iter.try_rfold(init, move |acc, item| { f(&item); fold(acc, item) })
+    }
+
+    #[inline]
+    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
+        where Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let mut f = self.f;
+        self.iter.rfold(init, move |acc, item| { f(&item); fold(acc, item) })
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: ExactSizeIterator, F> ExactSizeIterator for Inspect<I, F>
+    where F: FnMut(&I::Item)
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator, F> FusedIterator for Inspect<I, F>
+    where F: FnMut(&I::Item) {}
diff --git a/src/libcore/iter/adapters/zip.rs b/src/libcore/iter/adapters/zip.rs
new file mode 100644
index 0000000000000..3548d0e282602
--- /dev/null
+++ b/src/libcore/iter/adapters/zip.rs
@@ -0,0 +1,282 @@
+use cmp;
+use super::super::{Iterator, DoubleEndedIterator, ExactSizeIterator, FusedIterator, TrustedLen};
+
+/// An iterator that iterates two other iterators simultaneously.
+///
+/// This `struct` is created by the [`zip`] method on [`Iterator`]. See its
+/// documentation for more.
+///
+/// [`zip`]: trait.Iterator.html#method.zip
+/// [`Iterator`]: trait.Iterator.html
+#[derive(Clone, Debug)]
+#[must_use = "iterators are lazy and do nothing unless consumed"]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct Zip<A, B> {
+    a: A,
+    b: B,
+    // index and len are only used by the specialized version of zip
+    index: usize,
+    len: usize,
+}
+impl<A: Iterator, B: Iterator> Zip<A, B> {
+    pub(in super::super) fn new(a: A, b: B) -> Zip<A, B> {
+        ZipImpl::new(a, b)
+    }
+    fn super_nth(&mut self, mut n: usize) -> Option<(A::Item, B::Item)> {
+        while let Some(x) = Iterator::next(self) {
+            if n == 0 { return Some(x) }
+            n -= 1;
+        }
+        None
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> Iterator for Zip<A, B> where A: Iterator, B: Iterator
+{
+    type Item = (A::Item, B::Item);
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        ZipImpl::next(self)
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        ZipImpl::size_hint(self)
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        ZipImpl::nth(self, n)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> DoubleEndedIterator for Zip<A, B> where
+    A: DoubleEndedIterator + ExactSizeIterator,
+    B: DoubleEndedIterator + ExactSizeIterator,
+{
+    #[inline]
+    fn next_back(&mut self) -> Option<(A::Item, B::Item)> {
+        ZipImpl::next_back(self)
+    }
+}
+
+// Zip specialization trait
+#[doc(hidden)]
+trait ZipImpl<A, B> {
+    type Item;
+    fn new(a: A, b: B) -> Self;
+    fn next(&mut self) -> Option<Self::Item>;
+    fn size_hint(&self) -> (usize, Option<usize>);
+    fn nth(&mut self, n: usize) -> Option<Self::Item>;
+    fn next_back(&mut self) -> Option<Self::Item>
+        where A: DoubleEndedIterator + ExactSizeIterator,
+              B: DoubleEndedIterator + ExactSizeIterator;
+}
+
+// General Zip impl
+#[doc(hidden)]
+impl<A, B> ZipImpl<A, B> for Zip<A, B>
+    where A: Iterator, B: Iterator
+{
+    type Item = (A::Item, B::Item);
+    default fn new(a: A, b: B) -> Self {
+        Zip {
+            a,
+            b,
+            index: 0, // unused
+            len: 0, // unused
+        }
+    }
+
+    #[inline]
+    default fn next(&mut self) -> Option<(A::Item, B::Item)> {
+        self.a.next().and_then(|x| {
+            self.b.next().and_then(|y| {
+                Some((x, y))
+            })
+        })
+    }
+
+    #[inline]
+    default fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.super_nth(n)
+    }
+
+    #[inline]
+    default fn next_back(&mut self) -> Option<(A::Item, B::Item)>
+        where A: DoubleEndedIterator + ExactSizeIterator,
+              B: DoubleEndedIterator + ExactSizeIterator
+    {
+        let a_sz = self.a.len();
+        let b_sz = self.b.len();
+        if a_sz != b_sz {
+            // Adjust a, b to equal length
+            if a_sz > b_sz {
+                for _ in 0..a_sz - b_sz { self.a.next_back(); }
+            } else {
+                for _ in 0..b_sz - a_sz { self.b.next_back(); }
+            }
+        }
+        match (self.a.next_back(), self.b.next_back()) {
+            (Some(x), Some(y)) => Some((x, y)),
+            (None, None) => None,
+            _ => unreachable!(),
+        }
+    }
+
+    #[inline]
+    default fn size_hint(&self) -> (usize, Option<usize>) {
+        let (a_lower, a_upper) = self.a.size_hint();
+        let (b_lower, b_upper) = self.b.size_hint();
+
+        let lower = cmp::min(a_lower, b_lower);
+
+        let upper = match (a_upper, b_upper) {
+            (Some(x), Some(y)) => Some(cmp::min(x,y)),
+            (Some(x), None) => Some(x),
+            (None, Some(y)) => Some(y),
+            (None, None) => None
+        };
+
+        (lower, upper)
+    }
+}
+
+#[doc(hidden)]
+impl<A, B> ZipImpl<A, B> for Zip<A, B>
+    where A: TrustedRandomAccess, B: TrustedRandomAccess
+{
+    fn new(a: A, b: B) -> Self {
+        let len = cmp::min(a.len(), b.len());
+        Zip {
+            a,
+            b,
+            index: 0,
+            len,
+        }
+    }
+
+    #[inline]
+    fn next(&mut self) -> Option<(A::Item, B::Item)> {
+        if self.index < self.len {
+            let i = self.index;
+            self.index += 1;
+            unsafe {
+                Some((self.a.get_unchecked(i), self.b.get_unchecked(i)))
+            }
+        } else if A::may_have_side_effect() && self.index < self.a.len() {
+            // match the base implementation's potential side effects
+            unsafe {
+                self.a.get_unchecked(self.index);
+            }
+            self.index += 1;
+            None
+        } else {
+            None
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.len - self.index;
+        (len, Some(len))
+    }
+
+    #[inline]
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        let delta = cmp::min(n, self.len - self.index);
+        let end = self.index + delta;
+        while self.index < end {
+            let i = self.index;
+            self.index += 1;
+            if A::may_have_side_effect() {
+                unsafe { self.a.get_unchecked(i); }
+            }
+            if B::may_have_side_effect() {
+                unsafe { self.b.get_unchecked(i); }
+            }
+        }
+
+        self.super_nth(n - delta)
+    }
+
+    #[inline]
+    fn next_back(&mut self) -> Option<(A::Item, B::Item)>
+        where A: DoubleEndedIterator + ExactSizeIterator,
+              B: DoubleEndedIterator + ExactSizeIterator
+    {
+        // Adjust a, b to equal length
+        if A::may_have_side_effect() {
+            let sz = self.a.len();
+            if sz > self.len {
+                for _ in 0..sz - cmp::max(self.len, self.index) {
+                    self.a.next_back();
+                }
+            }
+        }
+        if B::may_have_side_effect() {
+            let sz = self.b.len();
+            if sz > self.len {
+                for _ in 0..sz - self.len {
+                    self.b.next_back();
+                }
+            }
+        }
+        if self.index < self.len {
+            self.len -= 1;
+            let i = self.len;
+            unsafe {
+                Some((self.a.get_unchecked(i), self.b.get_unchecked(i)))
+            }
+        } else {
+            None
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<A, B> ExactSizeIterator for Zip<A, B>
+    where A: ExactSizeIterator, B: ExactSizeIterator {}
+
+#[doc(hidden)]
+unsafe impl<A, B> TrustedRandomAccess for Zip<A, B>
+    where A: TrustedRandomAccess,
+          B: TrustedRandomAccess,
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> (A::Item, B::Item) {
+        (self.a.get_unchecked(i), self.b.get_unchecked(i))
+    }
+
+    fn may_have_side_effect() -> bool {
+        A::may_have_side_effect() || B::may_have_side_effect()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<A, B> FusedIterator for Zip<A, B>
+    where A: FusedIterator, B: FusedIterator, {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<A, B> TrustedLen for Zip<A, B>
+    where A: TrustedLen, B: TrustedLen,
+{}
+
+/// An iterator whose items are random-accessible efficiently
+///
+/// # Safety
+///
+/// The iterator's .len() and size_hint() must be exact.
+/// `.len()` must be cheap to call.
+///
+/// .get_unchecked() must return distinct mutable references for distinct
+/// indices (if applicable), and must return a valid reference if index is in
+/// 0..self.len().
+pub(crate) unsafe trait TrustedRandomAccess : ExactSizeIterator {
+    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item;
+    /// Returns `true` if getting an iterator element may have
+    /// side effects. Remember to take inner iterators into account.
+    fn may_have_side_effect() -> bool;
+}
diff --git a/src/libcore/iter/mod.rs b/src/libcore/iter/mod.rs
index 974906b682d21..5dcca7ee0ca01 100644
--- a/src/libcore/iter/mod.rs
+++ b/src/libcore/iter/mod.rs
@@ -306,15 +306,10 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use cmp;
-use fmt;
-use iter_private::TrustedRandomAccess;
 use ops::Try;
-use usize;
-use intrinsics;
 
 #[stable(feature = "rust1", since = "1.0.0")]
-pub use self::iterator::Iterator;
+pub use self::traits::Iterator;
 
 #[unstable(feature = "step_trait",
            reason = "likely to be replaced by finer-grained traits",
@@ -331,8 +326,10 @@ pub use self::sources::{Empty, empty};
 pub use self::sources::{Once, once};
 #[unstable(feature = "iter_once_with", issue = "57581")]
 pub use self::sources::{OnceWith, once_with};
-#[unstable(feature = "iter_unfold", issue = "55977")]
-pub use self::sources::{Unfold, unfold, Successors, successors};
+#[stable(feature = "iter_from_fn", since = "1.34.0")]
+pub use self::sources::{FromFn, from_fn};
+#[stable(feature = "iter_successors", since = "1.34.0")]
+pub use self::sources::{Successors, successors};
 
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::traits::{FromIterator, IntoIterator, DoubleEndedIterator, Extend};
@@ -343,10 +340,27 @@ pub use self::traits::FusedIterator;
 #[unstable(feature = "trusted_len", issue = "37572")]
 pub use self::traits::TrustedLen;
 
-mod iterator;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::adapters::{Rev, Cycle, Chain, Zip, Map, Filter, FilterMap, Enumerate};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::adapters::{Peekable, SkipWhile, TakeWhile, Skip, Take, Scan, FlatMap};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::adapters::{Fuse, Inspect};
+#[stable(feature = "iter_cloned", since = "1.1.0")]
+pub use self::adapters::Cloned;
+#[stable(feature = "iterator_step_by", since = "1.28.0")]
+pub use self::adapters::StepBy;
+#[stable(feature = "iterator_flatten", since = "1.29.0")]
+pub use self::adapters::Flatten;
+#[unstable(feature = "iter_copied", issue = "57127")]
+pub use self::adapters::Copied;
+
+pub(crate) use self::adapters::TrustedRandomAccess;
+
 mod range;
 mod sources;
 mod traits;
+mod adapters;
 
 /// Used to make try_fold closures more like normal loops
 #[derive(PartialEq)]
@@ -397,2767 +411,3 @@ impl<R: Try> LoopState<R::Ok, R> {
         }
     }
 }
-
-/// A double-ended iterator with the direction inverted.
-///
-/// This `struct` is created by the [`rev`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`rev`]: trait.Iterator.html#method.rev
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Rev<T> {
-    iter: T
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Rev<I> where I: DoubleEndedIterator {
-    type Item = <I as Iterator>::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next_back() }
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<<I as Iterator>::Item> { self.iter.nth_back(n) }
-
-    fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.iter.try_rfold(init, f)
-    }
-
-    fn fold<Acc, F>(self, init: Acc, f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.iter.rfold(init, f)
-    }
-
-    #[inline]
-    fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
-        where P: FnMut(&Self::Item) -> bool
-    {
-        self.iter.rfind(predicate)
-    }
-
-    #[inline]
-    fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
-        P: FnMut(Self::Item) -> bool
-    {
-        self.iter.position(predicate)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> DoubleEndedIterator for Rev<I> where I: DoubleEndedIterator {
-    #[inline]
-    fn next_back(&mut self) -> Option<<I as Iterator>::Item> { self.iter.next() }
-
-    #[inline]
-    fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item> { self.iter.nth(n) }
-
-    fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.iter.try_fold(init, f)
-    }
-
-    fn rfold<Acc, F>(self, init: Acc, f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.iter.fold(init, f)
-    }
-
-    fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
-        where P: FnMut(&Self::Item) -> bool
-    {
-        self.iter.find(predicate)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ExactSizeIterator for Rev<I>
-    where I: ExactSizeIterator + DoubleEndedIterator
-{
-    fn len(&self) -> usize {
-        self.iter.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Rev<I>
-    where I: FusedIterator + DoubleEndedIterator {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<I> TrustedLen for Rev<I>
-    where I: TrustedLen + DoubleEndedIterator {}
-
-/// An iterator that copies the elements of an underlying iterator.
-///
-/// This `struct` is created by the [`copied`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`copied`]: trait.Iterator.html#method.copied
-/// [`Iterator`]: trait.Iterator.html
-#[unstable(feature = "iter_copied", issue = "57127")]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[derive(Clone, Debug)]
-pub struct Copied<I> {
-    it: I,
-}
-
-#[unstable(feature = "iter_copied", issue = "57127")]
-impl<'a, I, T: 'a> Iterator for Copied<I>
-    where I: Iterator<Item=&'a T>, T: Copy
-{
-    type Item = T;
-
-    fn next(&mut self) -> Option<T> {
-        self.it.next().copied()
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.it.size_hint()
-    }
-
-    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.it.try_fold(init, move |acc, &elt| f(acc, elt))
-    }
-
-    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.it.fold(init, move |acc, &elt| f(acc, elt))
-    }
-}
-
-#[unstable(feature = "iter_copied", issue = "57127")]
-impl<'a, I, T: 'a> DoubleEndedIterator for Copied<I>
-    where I: DoubleEndedIterator<Item=&'a T>, T: Copy
-{
-    fn next_back(&mut self) -> Option<T> {
-        self.it.next_back().copied()
-    }
-
-    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.it.try_rfold(init, move |acc, &elt| f(acc, elt))
-    }
-
-    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.it.rfold(init, move |acc, &elt| f(acc, elt))
-    }
-}
-
-#[unstable(feature = "iter_copied", issue = "57127")]
-impl<'a, I, T: 'a> ExactSizeIterator for Copied<I>
-    where I: ExactSizeIterator<Item=&'a T>, T: Copy
-{
-    fn len(&self) -> usize {
-        self.it.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.it.is_empty()
-    }
-}
-
-#[unstable(feature = "iter_copied", issue = "57127")]
-impl<'a, I, T: 'a> FusedIterator for Copied<I>
-    where I: FusedIterator<Item=&'a T>, T: Copy
-{}
-
-#[doc(hidden)]
-unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Copied<I>
-    where I: TrustedRandomAccess<Item=&'a T>, T: Copy
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
-        *self.it.get_unchecked(i)
-    }
-
-    #[inline]
-    fn may_have_side_effect() -> bool {
-        I::may_have_side_effect()
-    }
-}
-
-#[unstable(feature = "iter_copied", issue = "57127")]
-unsafe impl<'a, I, T: 'a> TrustedLen for Copied<I>
-    where I: TrustedLen<Item=&'a T>,
-          T: Copy
-{}
-
-/// An iterator that clones the elements of an underlying iterator.
-///
-/// This `struct` is created by the [`cloned`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`cloned`]: trait.Iterator.html#method.cloned
-/// [`Iterator`]: trait.Iterator.html
-#[stable(feature = "iter_cloned", since = "1.1.0")]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[derive(Clone, Debug)]
-pub struct Cloned<I> {
-    it: I,
-}
-
-#[stable(feature = "iter_cloned", since = "1.1.0")]
-impl<'a, I, T: 'a> Iterator for Cloned<I>
-    where I: Iterator<Item=&'a T>, T: Clone
-{
-    type Item = T;
-
-    fn next(&mut self) -> Option<T> {
-        self.it.next().cloned()
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.it.size_hint()
-    }
-
-    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.it.try_fold(init, move |acc, elt| f(acc, elt.clone()))
-    }
-
-    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.it.fold(init, move |acc, elt| f(acc, elt.clone()))
-    }
-}
-
-#[stable(feature = "iter_cloned", since = "1.1.0")]
-impl<'a, I, T: 'a> DoubleEndedIterator for Cloned<I>
-    where I: DoubleEndedIterator<Item=&'a T>, T: Clone
-{
-    fn next_back(&mut self) -> Option<T> {
-        self.it.next_back().cloned()
-    }
-
-    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        self.it.try_rfold(init, move |acc, elt| f(acc, elt.clone()))
-    }
-
-    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.it.rfold(init, move |acc, elt| f(acc, elt.clone()))
-    }
-}
-
-#[stable(feature = "iter_cloned", since = "1.1.0")]
-impl<'a, I, T: 'a> ExactSizeIterator for Cloned<I>
-    where I: ExactSizeIterator<Item=&'a T>, T: Clone
-{
-    fn len(&self) -> usize {
-        self.it.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.it.is_empty()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<'a, I, T: 'a> FusedIterator for Cloned<I>
-    where I: FusedIterator<Item=&'a T>, T: Clone
-{}
-
-#[doc(hidden)]
-unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
-    where I: TrustedRandomAccess<Item=&'a T>, T: Clone
-{
-    default unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
-        self.it.get_unchecked(i).clone()
-    }
-
-    #[inline]
-    default fn may_have_side_effect() -> bool { true }
-}
-
-#[doc(hidden)]
-unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
-    where I: TrustedRandomAccess<Item=&'a T>, T: Copy
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
-        *self.it.get_unchecked(i)
-    }
-
-    #[inline]
-    fn may_have_side_effect() -> bool {
-        I::may_have_side_effect()
-    }
-}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<'a, I, T: 'a> TrustedLen for Cloned<I>
-    where I: TrustedLen<Item=&'a T>,
-          T: Clone
-{}
-
-/// An iterator that repeats endlessly.
-///
-/// This `struct` is created by the [`cycle`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`cycle`]: trait.Iterator.html#method.cycle
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Cycle<I> {
-    orig: I,
-    iter: I,
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Cycle<I> where I: Clone + Iterator {
-    type Item = <I as Iterator>::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<<I as Iterator>::Item> {
-        match self.iter.next() {
-            None => { self.iter = self.orig.clone(); self.iter.next() }
-            y => y
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        // the cycle iterator is either empty or infinite
-        match self.orig.size_hint() {
-            sz @ (0, Some(0)) => sz,
-            (0, _) => (0, None),
-            _ => (usize::MAX, None)
-        }
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Cycle<I> where I: Clone + Iterator {}
-
-/// An iterator for stepping iterators by a custom amount.
-///
-/// This `struct` is created by the [`step_by`] method on [`Iterator`]. See
-/// its documentation for more.
-///
-/// [`step_by`]: trait.Iterator.html#method.step_by
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "iterator_step_by", since = "1.28.0")]
-#[derive(Clone, Debug)]
-pub struct StepBy<I> {
-    iter: I,
-    step: usize,
-    first_take: bool,
-}
-
-#[stable(feature = "iterator_step_by", since = "1.28.0")]
-impl<I> Iterator for StepBy<I> where I: Iterator {
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<Self::Item> {
-        if self.first_take {
-            self.first_take = false;
-            self.iter.next()
-        } else {
-            self.iter.nth(self.step)
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let inner_hint = self.iter.size_hint();
-
-        if self.first_take {
-            let f = |n| if n == 0 { 0 } else { 1 + (n-1)/(self.step+1) };
-            (f(inner_hint.0), inner_hint.1.map(f))
-        } else {
-            let f = |n| n / (self.step+1);
-            (f(inner_hint.0), inner_hint.1.map(f))
-        }
-    }
-
-    #[inline]
-    fn nth(&mut self, mut n: usize) -> Option<Self::Item> {
-        if self.first_take {
-            self.first_take = false;
-            let first = self.iter.next();
-            if n == 0 {
-                return first;
-            }
-            n -= 1;
-        }
-        // n and self.step are indices, we need to add 1 to get the amount of elements
-        // When calling `.nth`, we need to subtract 1 again to convert back to an index
-        // step + 1 can't overflow because `.step_by` sets `self.step` to `step - 1`
-        let mut step = self.step + 1;
-        // n + 1 could overflow
-        // thus, if n is usize::MAX, instead of adding one, we call .nth(step)
-        if n == usize::MAX {
-            self.iter.nth(step - 1);
-        } else {
-            n += 1;
-        }
-
-        // overflow handling
-        loop {
-            let mul = n.checked_mul(step);
-            if unsafe { intrinsics::likely(mul.is_some()) } {
-                return self.iter.nth(mul.unwrap() - 1);
-            }
-            let div_n = usize::MAX / n;
-            let div_step = usize::MAX / step;
-            let nth_n = div_n * n;
-            let nth_step = div_step * step;
-            let nth = if nth_n > nth_step {
-                step -= div_n;
-                nth_n
-            } else {
-                n -= div_step;
-                nth_step
-            };
-            self.iter.nth(nth - 1);
-        }
-    }
-}
-
-// StepBy can only make the iterator shorter, so the len will still fit.
-#[stable(feature = "iterator_step_by", since = "1.28.0")]
-impl<I> ExactSizeIterator for StepBy<I> where I: ExactSizeIterator {}
-
-/// An iterator that strings two iterators together.
-///
-/// This `struct` is created by the [`chain`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`chain`]: trait.Iterator.html#method.chain
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Chain<A, B> {
-    a: A,
-    b: B,
-    state: ChainState,
-}
-
-// The iterator protocol specifies that iteration ends with the return value
-// `None` from `.next()` (or `.next_back()`) and it is unspecified what
-// further calls return. The chain adaptor must account for this since it uses
-// two subiterators.
-//
-//  It uses three states:
-//
-//  - Both: `a` and `b` are remaining
-//  - Front: `a` remaining
-//  - Back: `b` remaining
-//
-//  The fourth state (neither iterator is remaining) only occurs after Chain has
-//  returned None once, so we don't need to store this state.
-#[derive(Clone, Debug)]
-enum ChainState {
-    // both front and back iterator are remaining
-    Both,
-    // only front is remaining
-    Front,
-    // only back is remaining
-    Back,
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<A, B> Iterator for Chain<A, B> where
-    A: Iterator,
-    B: Iterator<Item = A::Item>
-{
-    type Item = A::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<A::Item> {
-        match self.state {
-            ChainState::Both => match self.a.next() {
-                elt @ Some(..) => elt,
-                None => {
-                    self.state = ChainState::Back;
-                    self.b.next()
-                }
-            },
-            ChainState::Front => self.a.next(),
-            ChainState::Back => self.b.next(),
-        }
-    }
-
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn count(self) -> usize {
-        match self.state {
-            ChainState::Both => self.a.count() + self.b.count(),
-            ChainState::Front => self.a.count(),
-            ChainState::Back => self.b.count(),
-        }
-    }
-
-    fn try_fold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R where
-        Self: Sized, F: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let mut accum = init;
-        match self.state {
-            ChainState::Both | ChainState::Front => {
-                accum = self.a.try_fold(accum, &mut f)?;
-                if let ChainState::Both = self.state {
-                    self.state = ChainState::Back;
-                }
-            }
-            _ => { }
-        }
-        if let ChainState::Back = self.state {
-            accum = self.b.try_fold(accum, &mut f)?;
-        }
-        Try::from_ok(accum)
-    }
-
-    fn fold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut accum = init;
-        match self.state {
-            ChainState::Both | ChainState::Front => {
-                accum = self.a.fold(accum, &mut f);
-            }
-            _ => { }
-        }
-        match self.state {
-            ChainState::Both | ChainState::Back => {
-                accum = self.b.fold(accum, &mut f);
-            }
-            _ => { }
-        }
-        accum
-    }
-
-    #[inline]
-    fn nth(&mut self, mut n: usize) -> Option<A::Item> {
-        match self.state {
-            ChainState::Both | ChainState::Front => {
-                for x in self.a.by_ref() {
-                    if n == 0 {
-                        return Some(x)
-                    }
-                    n -= 1;
-                }
-                if let ChainState::Both = self.state {
-                    self.state = ChainState::Back;
-                }
-            }
-            ChainState::Back => {}
-        }
-        if let ChainState::Back = self.state {
-            self.b.nth(n)
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn find<P>(&mut self, mut predicate: P) -> Option<Self::Item> where
-        P: FnMut(&Self::Item) -> bool,
-    {
-        match self.state {
-            ChainState::Both => match self.a.find(&mut predicate) {
-                None => {
-                    self.state = ChainState::Back;
-                    self.b.find(predicate)
-                }
-                v => v
-            },
-            ChainState::Front => self.a.find(predicate),
-            ChainState::Back => self.b.find(predicate),
-        }
-    }
-
-    #[inline]
-    fn last(self) -> Option<A::Item> {
-        match self.state {
-            ChainState::Both => {
-                // Must exhaust a before b.
-                let a_last = self.a.last();
-                let b_last = self.b.last();
-                b_last.or(a_last)
-            },
-            ChainState::Front => self.a.last(),
-            ChainState::Back => self.b.last()
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (a_lower, a_upper) = self.a.size_hint();
-        let (b_lower, b_upper) = self.b.size_hint();
-
-        let lower = a_lower.saturating_add(b_lower);
-
-        let upper = match (a_upper, b_upper) {
-            (Some(x), Some(y)) => x.checked_add(y),
-            _ => None
-        };
-
-        (lower, upper)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<A, B> DoubleEndedIterator for Chain<A, B> where
-    A: DoubleEndedIterator,
-    B: DoubleEndedIterator<Item=A::Item>,
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<A::Item> {
-        match self.state {
-            ChainState::Both => match self.b.next_back() {
-                elt @ Some(..) => elt,
-                None => {
-                    self.state = ChainState::Front;
-                    self.a.next_back()
-                }
-            },
-            ChainState::Front => self.a.next_back(),
-            ChainState::Back => self.b.next_back(),
-        }
-    }
-
-    fn try_rfold<Acc, F, R>(&mut self, init: Acc, mut f: F) -> R where
-        Self: Sized, F: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let mut accum = init;
-        match self.state {
-            ChainState::Both | ChainState::Back => {
-                accum = self.b.try_rfold(accum, &mut f)?;
-                if let ChainState::Both = self.state {
-                    self.state = ChainState::Front;
-                }
-            }
-            _ => { }
-        }
-        if let ChainState::Front = self.state {
-            accum = self.a.try_rfold(accum, &mut f)?;
-        }
-        Try::from_ok(accum)
-    }
-
-    fn rfold<Acc, F>(self, init: Acc, mut f: F) -> Acc
-        where F: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut accum = init;
-        match self.state {
-            ChainState::Both | ChainState::Back => {
-                accum = self.b.rfold(accum, &mut f);
-            }
-            _ => { }
-        }
-        match self.state {
-            ChainState::Both | ChainState::Front => {
-                accum = self.a.rfold(accum, &mut f);
-            }
-            _ => { }
-        }
-        accum
-    }
-
-}
-
-// Note: *both* must be fused to handle double-ended iterators.
-#[stable(feature = "fused", since = "1.26.0")]
-impl<A, B> FusedIterator for Chain<A, B>
-    where A: FusedIterator,
-          B: FusedIterator<Item=A::Item>,
-{}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<A, B> TrustedLen for Chain<A, B>
-    where A: TrustedLen, B: TrustedLen<Item=A::Item>,
-{}
-
-/// An iterator that iterates two other iterators simultaneously.
-///
-/// This `struct` is created by the [`zip`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`zip`]: trait.Iterator.html#method.zip
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Zip<A, B> {
-    a: A,
-    b: B,
-    // index and len are only used by the specialized version of zip
-    index: usize,
-    len: usize,
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<A, B> Iterator for Zip<A, B> where A: Iterator, B: Iterator
-{
-    type Item = (A::Item, B::Item);
-
-    #[inline]
-    fn next(&mut self) -> Option<Self::Item> {
-        ZipImpl::next(self)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        ZipImpl::size_hint(self)
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<Self::Item> {
-        ZipImpl::nth(self, n)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<A, B> DoubleEndedIterator for Zip<A, B> where
-    A: DoubleEndedIterator + ExactSizeIterator,
-    B: DoubleEndedIterator + ExactSizeIterator,
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<(A::Item, B::Item)> {
-        ZipImpl::next_back(self)
-    }
-}
-
-// Zip specialization trait
-#[doc(hidden)]
-trait ZipImpl<A, B> {
-    type Item;
-    fn new(a: A, b: B) -> Self;
-    fn next(&mut self) -> Option<Self::Item>;
-    fn size_hint(&self) -> (usize, Option<usize>);
-    fn nth(&mut self, n: usize) -> Option<Self::Item>;
-    fn super_nth(&mut self, mut n: usize) -> Option<Self::Item> {
-        while let Some(x) = self.next() {
-            if n == 0 { return Some(x) }
-            n -= 1;
-        }
-        None
-    }
-    fn next_back(&mut self) -> Option<Self::Item>
-        where A: DoubleEndedIterator + ExactSizeIterator,
-              B: DoubleEndedIterator + ExactSizeIterator;
-}
-
-// General Zip impl
-#[doc(hidden)]
-impl<A, B> ZipImpl<A, B> for Zip<A, B>
-    where A: Iterator, B: Iterator
-{
-    type Item = (A::Item, B::Item);
-    default fn new(a: A, b: B) -> Self {
-        Zip {
-            a,
-            b,
-            index: 0, // unused
-            len: 0, // unused
-        }
-    }
-
-    #[inline]
-    default fn next(&mut self) -> Option<(A::Item, B::Item)> {
-        self.a.next().and_then(|x| {
-            self.b.next().and_then(|y| {
-                Some((x, y))
-            })
-        })
-    }
-
-    #[inline]
-    default fn nth(&mut self, n: usize) -> Option<Self::Item> {
-        self.super_nth(n)
-    }
-
-    #[inline]
-    default fn next_back(&mut self) -> Option<(A::Item, B::Item)>
-        where A: DoubleEndedIterator + ExactSizeIterator,
-              B: DoubleEndedIterator + ExactSizeIterator
-    {
-        let a_sz = self.a.len();
-        let b_sz = self.b.len();
-        if a_sz != b_sz {
-            // Adjust a, b to equal length
-            if a_sz > b_sz {
-                for _ in 0..a_sz - b_sz { self.a.next_back(); }
-            } else {
-                for _ in 0..b_sz - a_sz { self.b.next_back(); }
-            }
-        }
-        match (self.a.next_back(), self.b.next_back()) {
-            (Some(x), Some(y)) => Some((x, y)),
-            (None, None) => None,
-            _ => unreachable!(),
-        }
-    }
-
-    #[inline]
-    default fn size_hint(&self) -> (usize, Option<usize>) {
-        let (a_lower, a_upper) = self.a.size_hint();
-        let (b_lower, b_upper) = self.b.size_hint();
-
-        let lower = cmp::min(a_lower, b_lower);
-
-        let upper = match (a_upper, b_upper) {
-            (Some(x), Some(y)) => Some(cmp::min(x,y)),
-            (Some(x), None) => Some(x),
-            (None, Some(y)) => Some(y),
-            (None, None) => None
-        };
-
-        (lower, upper)
-    }
-}
-
-#[doc(hidden)]
-impl<A, B> ZipImpl<A, B> for Zip<A, B>
-    where A: TrustedRandomAccess, B: TrustedRandomAccess
-{
-    fn new(a: A, b: B) -> Self {
-        let len = cmp::min(a.len(), b.len());
-        Zip {
-            a,
-            b,
-            index: 0,
-            len,
-        }
-    }
-
-    #[inline]
-    fn next(&mut self) -> Option<(A::Item, B::Item)> {
-        if self.index < self.len {
-            let i = self.index;
-            self.index += 1;
-            unsafe {
-                Some((self.a.get_unchecked(i), self.b.get_unchecked(i)))
-            }
-        } else if A::may_have_side_effect() && self.index < self.a.len() {
-            // match the base implementation's potential side effects
-            unsafe {
-                self.a.get_unchecked(self.index);
-            }
-            self.index += 1;
-            None
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let len = self.len - self.index;
-        (len, Some(len))
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<Self::Item> {
-        let delta = cmp::min(n, self.len - self.index);
-        let end = self.index + delta;
-        while self.index < end {
-            let i = self.index;
-            self.index += 1;
-            if A::may_have_side_effect() {
-                unsafe { self.a.get_unchecked(i); }
-            }
-            if B::may_have_side_effect() {
-                unsafe { self.b.get_unchecked(i); }
-            }
-        }
-
-        self.super_nth(n - delta)
-    }
-
-    #[inline]
-    fn next_back(&mut self) -> Option<(A::Item, B::Item)>
-        where A: DoubleEndedIterator + ExactSizeIterator,
-              B: DoubleEndedIterator + ExactSizeIterator
-    {
-        // Adjust a, b to equal length
-        if A::may_have_side_effect() {
-            let sz = self.a.len();
-            if sz > self.len {
-                for _ in 0..sz - cmp::max(self.len, self.index) {
-                    self.a.next_back();
-                }
-            }
-        }
-        if B::may_have_side_effect() {
-            let sz = self.b.len();
-            if sz > self.len {
-                for _ in 0..sz - self.len {
-                    self.b.next_back();
-                }
-            }
-        }
-        if self.index < self.len {
-            self.len -= 1;
-            let i = self.len;
-            unsafe {
-                Some((self.a.get_unchecked(i), self.b.get_unchecked(i)))
-            }
-        } else {
-            None
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<A, B> ExactSizeIterator for Zip<A, B>
-    where A: ExactSizeIterator, B: ExactSizeIterator {}
-
-#[doc(hidden)]
-unsafe impl<A, B> TrustedRandomAccess for Zip<A, B>
-    where A: TrustedRandomAccess,
-          B: TrustedRandomAccess,
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> (A::Item, B::Item) {
-        (self.a.get_unchecked(i), self.b.get_unchecked(i))
-    }
-
-    fn may_have_side_effect() -> bool {
-        A::may_have_side_effect() || B::may_have_side_effect()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<A, B> FusedIterator for Zip<A, B>
-    where A: FusedIterator, B: FusedIterator, {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<A, B> TrustedLen for Zip<A, B>
-    where A: TrustedLen, B: TrustedLen,
-{}
-
-/// An iterator that maps the values of `iter` with `f`.
-///
-/// This `struct` is created by the [`map`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`map`]: trait.Iterator.html#method.map
-/// [`Iterator`]: trait.Iterator.html
-///
-/// # Notes about side effects
-///
-/// The [`map`] iterator implements [`DoubleEndedIterator`], meaning that
-/// you can also [`map`] backwards:
-///
-/// ```rust
-/// let v: Vec<i32> = vec![1, 2, 3].into_iter().map(|x| x + 1).rev().collect();
-///
-/// assert_eq!(v, [4, 3, 2]);
-/// ```
-///
-/// [`DoubleEndedIterator`]: trait.DoubleEndedIterator.html
-///
-/// But if your closure has state, iterating backwards may act in a way you do
-/// not expect. Let's go through an example. First, in the forward direction:
-///
-/// ```rust
-/// let mut c = 0;
-///
-/// for pair in vec!['a', 'b', 'c'].into_iter()
-///                                .map(|letter| { c += 1; (letter, c) }) {
-///     println!("{:?}", pair);
-/// }
-/// ```
-///
-/// This will print "('a', 1), ('b', 2), ('c', 3)".
-///
-/// Now consider this twist where we add a call to `rev`. This version will
-/// print `('c', 1), ('b', 2), ('a', 3)`. Note that the letters are reversed,
-/// but the values of the counter still go in order. This is because `map()` is
-/// still being called lazily on each item, but we are popping items off the
-/// back of the vector now, instead of shifting them from the front.
-///
-/// ```rust
-/// let mut c = 0;
-///
-/// for pair in vec!['a', 'b', 'c'].into_iter()
-///                                .map(|letter| { c += 1; (letter, c) })
-///                                .rev() {
-///     println!("{:?}", pair);
-/// }
-/// ```
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct Map<I, F> {
-    iter: I,
-    f: F,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, F> fmt::Debug for Map<I, F> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Map")
-            .field("iter", &self.iter)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: Iterator, F> Iterator for Map<I, F> where F: FnMut(I::Item) -> B {
-    type Item = B;
-
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        self.iter.next().map(&mut self.f)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-
-    fn try_fold<Acc, G, R>(&mut self, init: Acc, mut g: G) -> R where
-        Self: Sized, G: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_fold(init, move |acc, elt| g(acc, f(elt)))
-    }
-
-    fn fold<Acc, G>(self, init: Acc, mut g: G) -> Acc
-        where G: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.fold(init, move |acc, elt| g(acc, f(elt)))
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for Map<I, F> where
-    F: FnMut(I::Item) -> B,
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<B> {
-        self.iter.next_back().map(&mut self.f)
-    }
-
-    fn try_rfold<Acc, G, R>(&mut self, init: Acc, mut g: G) -> R where
-        Self: Sized, G: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_rfold(init, move |acc, elt| g(acc, f(elt)))
-    }
-
-    fn rfold<Acc, G>(self, init: Acc, mut g: G) -> Acc
-        where G: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.rfold(init, move |acc, elt| g(acc, f(elt)))
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: ExactSizeIterator, F> ExactSizeIterator for Map<I, F>
-    where F: FnMut(I::Item) -> B
-{
-    fn len(&self) -> usize {
-        self.iter.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<B, I: FusedIterator, F> FusedIterator for Map<I, F>
-    where F: FnMut(I::Item) -> B {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<B, I, F> TrustedLen for Map<I, F>
-    where I: TrustedLen,
-          F: FnMut(I::Item) -> B {}
-
-#[doc(hidden)]
-unsafe impl<B, I, F> TrustedRandomAccess for Map<I, F>
-    where I: TrustedRandomAccess,
-          F: FnMut(I::Item) -> B,
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
-        (self.f)(self.iter.get_unchecked(i))
-    }
-    #[inline]
-    fn may_have_side_effect() -> bool { true }
-}
-
-/// An iterator that filters the elements of `iter` with `predicate`.
-///
-/// This `struct` is created by the [`filter`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`filter`]: trait.Iterator.html#method.filter
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct Filter<I, P> {
-    iter: I,
-    predicate: P,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, P> fmt::Debug for Filter<I, P> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Filter")
-            .field("iter", &self.iter)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator, P> Iterator for Filter<I, P> where P: FnMut(&I::Item) -> bool {
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        for x in &mut self.iter {
-            if (self.predicate)(&x) {
-                return Some(x);
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-
-    // this special case allows the compiler to make `.filter(_).count()`
-    // branchless. Barring perfect branch prediction (which is unattainable in
-    // the general case), this will be much faster in >90% of cases (containing
-    // virtually all real workloads) and only a tiny bit slower in the rest.
-    //
-    // Having this specialization thus allows us to write `.filter(p).count()`
-    // where we would otherwise write `.map(|x| p(x) as usize).sum()`, which is
-    // less readable and also less backwards-compatible to Rust before 1.10.
-    //
-    // Using the branchless version will also simplify the LLVM byte code, thus
-    // leaving more budget for LLVM optimizations.
-    #[inline]
-    fn count(mut self) -> usize {
-        let mut count = 0;
-        for x in &mut self.iter {
-            count += (self.predicate)(&x) as usize;
-        }
-        count
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let predicate = &mut self.predicate;
-        self.iter.try_fold(init, move |acc, item| if predicate(&item) {
-            fold(acc, item)
-        } else {
-            Try::from_ok(acc)
-        })
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut predicate = self.predicate;
-        self.iter.fold(init, move |acc, item| if predicate(&item) {
-            fold(acc, item)
-        } else {
-            acc
-        })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: DoubleEndedIterator, P> DoubleEndedIterator for Filter<I, P>
-    where P: FnMut(&I::Item) -> bool,
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<I::Item> {
-        for x in self.iter.by_ref().rev() {
-            if (self.predicate)(&x) {
-                return Some(x);
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let predicate = &mut self.predicate;
-        self.iter.try_rfold(init, move |acc, item| if predicate(&item) {
-            fold(acc, item)
-        } else {
-            Try::from_ok(acc)
-        })
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut predicate = self.predicate;
-        self.iter.rfold(init, move |acc, item| if predicate(&item) {
-            fold(acc, item)
-        } else {
-            acc
-        })
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I: FusedIterator, P> FusedIterator for Filter<I, P>
-    where P: FnMut(&I::Item) -> bool {}
-
-/// An iterator that uses `f` to both filter and map elements from `iter`.
-///
-/// This `struct` is created by the [`filter_map`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`filter_map`]: trait.Iterator.html#method.filter_map
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct FilterMap<I, F> {
-    iter: I,
-    f: F,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, F> fmt::Debug for FilterMap<I, F> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("FilterMap")
-            .field("iter", &self.iter)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: Iterator, F> Iterator for FilterMap<I, F>
-    where F: FnMut(I::Item) -> Option<B>,
-{
-    type Item = B;
-
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        for x in self.iter.by_ref() {
-            if let Some(y) = (self.f)(x) {
-                return Some(y);
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_fold(init, move |acc, item| match f(item) {
-            Some(x) => fold(acc, x),
-            None => Try::from_ok(acc),
-        })
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.fold(init, move |acc, item| match f(item) {
-            Some(x) => fold(acc, x),
-            None => acc,
-        })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I: DoubleEndedIterator, F> DoubleEndedIterator for FilterMap<I, F>
-    where F: FnMut(I::Item) -> Option<B>,
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<B> {
-        for x in self.iter.by_ref().rev() {
-            if let Some(y) = (self.f)(x) {
-                return Some(y);
-            }
-        }
-        None
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_rfold(init, move |acc, item| match f(item) {
-            Some(x) => fold(acc, x),
-            None => Try::from_ok(acc),
-        })
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.rfold(init, move |acc, item| match f(item) {
-            Some(x) => fold(acc, x),
-            None => acc,
-        })
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<B, I: FusedIterator, F> FusedIterator for FilterMap<I, F>
-    where F: FnMut(I::Item) -> Option<B> {}
-
-/// An iterator that yields the current count and the element during iteration.
-///
-/// This `struct` is created by the [`enumerate`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`enumerate`]: trait.Iterator.html#method.enumerate
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Enumerate<I> {
-    iter: I,
-    count: usize,
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Enumerate<I> where I: Iterator {
-    type Item = (usize, <I as Iterator>::Item);
-
-    /// # Overflow Behavior
-    ///
-    /// The method does no guarding against overflows, so enumerating more than
-    /// `usize::MAX` elements either produces the wrong result or panics. If
-    /// debug assertions are enabled, a panic is guaranteed.
-    ///
-    /// # Panics
-    ///
-    /// Might panic if the index of the element overflows a `usize`.
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn next(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
-        self.iter.next().map(|a| {
-            let ret = (self.count, a);
-            // Possible undefined overflow.
-            self.count += 1;
-            ret
-        })
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn nth(&mut self, n: usize) -> Option<(usize, I::Item)> {
-        self.iter.nth(n).map(|a| {
-            let i = self.count + n;
-            self.count = i + 1;
-            (i, a)
-        })
-    }
-
-    #[inline]
-    fn count(self) -> usize {
-        self.iter.count()
-    }
-
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let count = &mut self.count;
-        self.iter.try_fold(init, move |acc, item| {
-            let acc = fold(acc, (*count, item));
-            *count += 1;
-            acc
-        })
-    }
-
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut count = self.count;
-        self.iter.fold(init, move |acc, item| {
-            let acc = fold(acc, (count, item));
-            count += 1;
-            acc
-        })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> DoubleEndedIterator for Enumerate<I> where
-    I: ExactSizeIterator + DoubleEndedIterator
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<(usize, <I as Iterator>::Item)> {
-        self.iter.next_back().map(|a| {
-            let len = self.iter.len();
-            // Can safely add, `ExactSizeIterator` promises that the number of
-            // elements fits into a `usize`.
-            (self.count + len, a)
-        })
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        // Can safely add and subtract the count, as `ExactSizeIterator` promises
-        // that the number of elements fits into a `usize`.
-        let mut count = self.count + self.iter.len();
-        self.iter.try_rfold(init, move |acc, item| {
-            count -= 1;
-            fold(acc, (count, item))
-        })
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        // Can safely add and subtract the count, as `ExactSizeIterator` promises
-        // that the number of elements fits into a `usize`.
-        let mut count = self.count + self.iter.len();
-        self.iter.rfold(init, move |acc, item| {
-            count -= 1;
-            fold(acc, (count, item))
-        })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ExactSizeIterator for Enumerate<I> where I: ExactSizeIterator {
-    fn len(&self) -> usize {
-        self.iter.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-#[doc(hidden)]
-unsafe impl<I> TrustedRandomAccess for Enumerate<I>
-    where I: TrustedRandomAccess
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> (usize, I::Item) {
-        (self.count + i, self.iter.get_unchecked(i))
-    }
-
-    fn may_have_side_effect() -> bool {
-        I::may_have_side_effect()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Enumerate<I> where I: FusedIterator {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<I> TrustedLen for Enumerate<I>
-    where I: TrustedLen,
-{}
-
-
-/// An iterator with a `peek()` that returns an optional reference to the next
-/// element.
-///
-/// This `struct` is created by the [`peekable`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`peekable`]: trait.Iterator.html#method.peekable
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Peekable<I: Iterator> {
-    iter: I,
-    /// Remember a peeked value, even if it was None.
-    peeked: Option<Option<I::Item>>,
-}
-
-// Peekable must remember if a None has been seen in the `.peek()` method.
-// It ensures that `.peek(); .peek();` or `.peek(); .next();` only advances the
-// underlying iterator at most once. This does not by itself make the iterator
-// fused.
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator> Iterator for Peekable<I> {
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        match self.peeked.take() {
-            Some(v) => v,
-            None => self.iter.next(),
-        }
-    }
-
-    #[inline]
-    #[rustc_inherit_overflow_checks]
-    fn count(mut self) -> usize {
-        match self.peeked.take() {
-            Some(None) => 0,
-            Some(Some(_)) => 1 + self.iter.count(),
-            None => self.iter.count(),
-        }
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<I::Item> {
-        match self.peeked.take() {
-            Some(None) => None,
-            Some(v @ Some(_)) if n == 0 => v,
-            Some(Some(_)) => self.iter.nth(n - 1),
-            None => self.iter.nth(n),
-        }
-    }
-
-    #[inline]
-    fn last(mut self) -> Option<I::Item> {
-        let peek_opt = match self.peeked.take() {
-            Some(None) => return None,
-            Some(v) => v,
-            None => None,
-        };
-        self.iter.last().or(peek_opt)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let peek_len = match self.peeked {
-            Some(None) => return (0, Some(0)),
-            Some(Some(_)) => 1,
-            None => 0,
-        };
-        let (lo, hi) = self.iter.size_hint();
-        let lo = lo.saturating_add(peek_len);
-        let hi = hi.and_then(|x| x.checked_add(peek_len));
-        (lo, hi)
-    }
-
-    #[inline]
-    fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R where
-        Self: Sized, F: FnMut(B, Self::Item) -> R, R: Try<Ok=B>
-    {
-        let acc = match self.peeked.take() {
-            Some(None) => return Try::from_ok(init),
-            Some(Some(v)) => f(init, v)?,
-            None => init,
-        };
-        self.iter.try_fold(acc, f)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let acc = match self.peeked {
-            Some(None) => return init,
-            Some(Some(v)) => fold(init, v),
-            None => init,
-        };
-        self.iter.fold(acc, fold)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: ExactSizeIterator> ExactSizeIterator for Peekable<I> {}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I: FusedIterator> FusedIterator for Peekable<I> {}
-
-impl<I: Iterator> Peekable<I> {
-    /// Returns a reference to the next() value without advancing the iterator.
-    ///
-    /// Like [`next`], if there is a value, it is wrapped in a `Some(T)`.
-    /// But if the iteration is over, `None` is returned.
-    ///
-    /// [`next`]: trait.Iterator.html#tymethod.next
-    ///
-    /// Because `peek()` returns a reference, and many iterators iterate over
-    /// references, there can be a possibly confusing situation where the
-    /// return value is a double reference. You can see this effect in the
-    /// examples below.
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let xs = [1, 2, 3];
-    ///
-    /// let mut iter = xs.iter().peekable();
-    ///
-    /// // peek() lets us see into the future
-    /// assert_eq!(iter.peek(), Some(&&1));
-    /// assert_eq!(iter.next(), Some(&1));
-    ///
-    /// assert_eq!(iter.next(), Some(&2));
-    ///
-    /// // The iterator does not advance even if we `peek` multiple times
-    /// assert_eq!(iter.peek(), Some(&&3));
-    /// assert_eq!(iter.peek(), Some(&&3));
-    ///
-    /// assert_eq!(iter.next(), Some(&3));
-    ///
-    /// // After the iterator is finished, so is `peek()`
-    /// assert_eq!(iter.peek(), None);
-    /// assert_eq!(iter.next(), None);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn peek(&mut self) -> Option<&I::Item> {
-        let iter = &mut self.iter;
-        self.peeked.get_or_insert_with(|| iter.next()).as_ref()
-    }
-}
-
-/// An iterator that rejects elements while `predicate` is true.
-///
-/// This `struct` is created by the [`skip_while`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`skip_while`]: trait.Iterator.html#method.skip_while
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct SkipWhile<I, P> {
-    iter: I,
-    flag: bool,
-    predicate: P,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, P> fmt::Debug for SkipWhile<I, P> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("SkipWhile")
-            .field("iter", &self.iter)
-            .field("flag", &self.flag)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator, P> Iterator for SkipWhile<I, P>
-    where P: FnMut(&I::Item) -> bool
-{
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        let flag = &mut self.flag;
-        let pred = &mut self.predicate;
-        self.iter.find(move |x| {
-            if *flag || !pred(x) {
-                *flag = true;
-                true
-            } else {
-                false
-            }
-        })
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the predicate
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if !self.flag {
-            match self.next() {
-                Some(v) => init = fold(init, v)?,
-                None => return Try::from_ok(init),
-            }
-        }
-        self.iter.try_fold(init, fold)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(mut self, mut init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        if !self.flag {
-            match self.next() {
-                Some(v) => init = fold(init, v),
-                None => return init,
-            }
-        }
-        self.iter.fold(init, fold)
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I, P> FusedIterator for SkipWhile<I, P>
-    where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
-
-/// An iterator that only accepts elements while `predicate` is true.
-///
-/// This `struct` is created by the [`take_while`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`take_while`]: trait.Iterator.html#method.take_while
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct TakeWhile<I, P> {
-    iter: I,
-    flag: bool,
-    predicate: P,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, P> fmt::Debug for TakeWhile<I, P> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("TakeWhile")
-            .field("iter", &self.iter)
-            .field("flag", &self.flag)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator, P> Iterator for TakeWhile<I, P>
-    where P: FnMut(&I::Item) -> bool
-{
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        if self.flag {
-            None
-        } else {
-            self.iter.next().and_then(|x| {
-                if (self.predicate)(&x) {
-                    Some(x)
-                } else {
-                    self.flag = true;
-                    None
-                }
-            })
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.flag {
-            (0, Some(0))
-        } else {
-            let (_, upper) = self.iter.size_hint();
-            (0, upper) // can't know a lower bound, due to the predicate
-        }
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if self.flag {
-            Try::from_ok(init)
-        } else {
-            let flag = &mut self.flag;
-            let p = &mut self.predicate;
-            self.iter.try_fold(init, move |acc, x|{
-                if p(&x) {
-                    LoopState::from_try(fold(acc, x))
-                } else {
-                    *flag = true;
-                    LoopState::Break(Try::from_ok(acc))
-                }
-            }).into_try()
-        }
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I, P> FusedIterator for TakeWhile<I, P>
-    where I: FusedIterator, P: FnMut(&I::Item) -> bool {}
-
-/// An iterator that skips over `n` elements of `iter`.
-///
-/// This `struct` is created by the [`skip`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`skip`]: trait.Iterator.html#method.skip
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Skip<I> {
-    iter: I,
-    n: usize
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Skip<I> where I: Iterator {
-    type Item = <I as Iterator>::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        if self.n == 0 {
-            self.iter.next()
-        } else {
-            let old_n = self.n;
-            self.n = 0;
-            self.iter.nth(old_n)
-        }
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<I::Item> {
-        // Can't just add n + self.n due to overflow.
-        if self.n == 0 {
-            self.iter.nth(n)
-        } else {
-            let to_skip = self.n;
-            self.n = 0;
-            // nth(n) skips n+1
-            if self.iter.nth(to_skip-1).is_none() {
-                return None;
-            }
-            self.iter.nth(n)
-        }
-    }
-
-    #[inline]
-    fn count(self) -> usize {
-        self.iter.count().saturating_sub(self.n)
-    }
-
-    #[inline]
-    fn last(mut self) -> Option<I::Item> {
-        if self.n == 0 {
-            self.iter.last()
-        } else {
-            let next = self.next();
-            if next.is_some() {
-                // recurse. n should be 0.
-                self.last().or(next)
-            } else {
-                None
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (lower, upper) = self.iter.size_hint();
-
-        let lower = lower.saturating_sub(self.n);
-        let upper = upper.map(|x| x.saturating_sub(self.n));
-
-        (lower, upper)
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let n = self.n;
-        self.n = 0;
-        if n > 0 {
-            // nth(n) skips n+1
-            if self.iter.nth(n - 1).is_none() {
-                return Try::from_ok(init);
-            }
-        }
-        self.iter.try_fold(init, fold)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        if self.n > 0 {
-            // nth(n) skips n+1
-            if self.iter.nth(self.n - 1).is_none() {
-                return init;
-            }
-        }
-        self.iter.fold(init, fold)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ExactSizeIterator for Skip<I> where I: ExactSizeIterator {}
-
-#[stable(feature = "double_ended_skip_iterator", since = "1.9.0")]
-impl<I> DoubleEndedIterator for Skip<I> where I: DoubleEndedIterator + ExactSizeIterator {
-    fn next_back(&mut self) -> Option<Self::Item> {
-        if self.len() > 0 {
-            self.iter.next_back()
-        } else {
-            None
-        }
-    }
-
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let mut n = self.len();
-        if n == 0 {
-            Try::from_ok(init)
-        } else {
-            self.iter.try_rfold(init, move |acc, x| {
-                n -= 1;
-                let r = fold(acc, x);
-                if n == 0 { LoopState::Break(r) }
-                else { LoopState::from_try(r) }
-            }).into_try()
-        }
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Skip<I> where I: FusedIterator {}
-
-/// An iterator that only iterates over the first `n` iterations of `iter`.
-///
-/// This `struct` is created by the [`take`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`take`]: trait.Iterator.html#method.take
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Take<I> {
-    iter: I,
-    n: usize
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Take<I> where I: Iterator{
-    type Item = <I as Iterator>::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<<I as Iterator>::Item> {
-        if self.n != 0 {
-            self.n -= 1;
-            self.iter.next()
-        } else {
-            None
-        }
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<I::Item> {
-        if self.n > n {
-            self.n -= n + 1;
-            self.iter.nth(n)
-        } else {
-            if self.n > 0 {
-                self.iter.nth(self.n - 1);
-                self.n = 0;
-            }
-            None
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.n == 0 {
-            return (0, Some(0));
-        }
-
-        let (lower, upper) = self.iter.size_hint();
-
-        let lower = cmp::min(lower, self.n);
-
-        let upper = match upper {
-            Some(x) if x < self.n => Some(x),
-            _ => Some(self.n)
-        };
-
-        (lower, upper)
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if self.n == 0 {
-            Try::from_ok(init)
-        } else {
-            let n = &mut self.n;
-            self.iter.try_fold(init, move |acc, x| {
-                *n -= 1;
-                let r = fold(acc, x);
-                if *n == 0 { LoopState::Break(r) }
-                else { LoopState::from_try(r) }
-            }).into_try()
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ExactSizeIterator for Take<I> where I: ExactSizeIterator {}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Take<I> where I: FusedIterator {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<I: TrustedLen> TrustedLen for Take<I> {}
-
-/// An iterator to maintain state while iterating another iterator.
-///
-/// This `struct` is created by the [`scan`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`scan`]: trait.Iterator.html#method.scan
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct Scan<I, St, F> {
-    iter: I,
-    f: F,
-    state: St,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, St: fmt::Debug, F> fmt::Debug for Scan<I, St, F> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Scan")
-            .field("iter", &self.iter)
-            .field("state", &self.state)
-            .finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<B, I, St, F> Iterator for Scan<I, St, F> where
-    I: Iterator,
-    F: FnMut(&mut St, I::Item) -> Option<B>,
-{
-    type Item = B;
-
-    #[inline]
-    fn next(&mut self) -> Option<B> {
-        self.iter.next().and_then(|a| (self.f)(&mut self.state, a))
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper) // can't know a lower bound, due to the scan function
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let state = &mut self.state;
-        let f = &mut self.f;
-        self.iter.try_fold(init, move |acc, x| {
-            match f(state, x) {
-                None => LoopState::Break(Try::from_ok(acc)),
-                Some(x) => LoopState::from_try(fold(acc, x)),
-            }
-        }).into_try()
-    }
-}
-
-/// An iterator that maps each element to an iterator, and yields the elements
-/// of the produced iterators.
-///
-/// This `struct` is created by the [`flat_map`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`flat_map`]: trait.Iterator.html#method.flat_map
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct FlatMap<I, U: IntoIterator, F> {
-    inner: FlattenCompat<Map<I, F>, <U as IntoIterator>::IntoIter>
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Clone, U: Clone + IntoIterator, F: Clone> Clone for FlatMap<I, U, F>
-    where <U as IntoIterator>::IntoIter: Clone
-{
-    fn clone(&self) -> Self { FlatMap { inner: self.inner.clone() } }
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, U: IntoIterator, F> fmt::Debug for FlatMap<I, U, F>
-    where U::IntoIter: fmt::Debug
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("FlatMap").field("inner", &self.inner).finish()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F>
-    where F: FnMut(I::Item) -> U,
-{
-    type Item = U::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<U::Item> { self.inner.next() }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.inner.try_fold(init, fold)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.inner.fold(init, fold)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: DoubleEndedIterator, U, F> DoubleEndedIterator for FlatMap<I, U, F>
-    where F: FnMut(I::Item) -> U,
-          U: IntoIterator,
-          U::IntoIter: DoubleEndedIterator
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<U::Item> { self.inner.next_back() }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.inner.try_rfold(init, fold)
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.inner.rfold(init, fold)
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I, U, F> FusedIterator for FlatMap<I, U, F>
-    where I: FusedIterator, U: IntoIterator, F: FnMut(I::Item) -> U {}
-
-/// An iterator that flattens one level of nesting in an iterator of things
-/// that can be turned into iterators.
-///
-/// This `struct` is created by the [`flatten`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`flatten`]: trait.Iterator.html#method.flatten
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-pub struct Flatten<I: Iterator>
-where I::Item: IntoIterator {
-    inner: FlattenCompat<I, <I::Item as IntoIterator>::IntoIter>,
-}
-
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-impl<I, U> fmt::Debug for Flatten<I>
-    where I: Iterator + fmt::Debug, U: Iterator + fmt::Debug,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>,
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Flatten").field("inner", &self.inner).finish()
-    }
-}
-
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-impl<I, U> Clone for Flatten<I>
-    where I: Iterator + Clone, U: Iterator + Clone,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>,
-{
-    fn clone(&self) -> Self { Flatten { inner: self.inner.clone() } }
-}
-
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-impl<I, U> Iterator for Flatten<I>
-    where I: Iterator, U: Iterator,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
-{
-    type Item = U::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<U::Item> { self.inner.next() }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.inner.try_fold(init, fold)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.inner.fold(init, fold)
-    }
-}
-
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-impl<I, U> DoubleEndedIterator for Flatten<I>
-    where I: DoubleEndedIterator, U: DoubleEndedIterator,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<U::Item> { self.inner.next_back() }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.inner.try_rfold(init, fold)
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.inner.rfold(init, fold)
-    }
-}
-
-#[stable(feature = "iterator_flatten", since = "1.29.0")]
-impl<I, U> FusedIterator for Flatten<I>
-    where I: FusedIterator, U: Iterator,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item> {}
-
-/// Adapts an iterator by flattening it, for use in `flatten()` and `flat_map()`.
-fn flatten_compat<I, U>(iter: I) -> FlattenCompat<I, U> {
-    FlattenCompat { iter, frontiter: None, backiter: None }
-}
-
-/// Real logic of both `Flatten` and `FlatMap` which simply delegate to
-/// this type.
-#[derive(Clone, Debug)]
-struct FlattenCompat<I, U> {
-    iter: I,
-    frontiter: Option<U>,
-    backiter: Option<U>,
-}
-
-impl<I, U> Iterator for FlattenCompat<I, U>
-    where I: Iterator, U: Iterator,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
-{
-    type Item = U::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<U::Item> {
-        loop {
-            if let Some(ref mut inner) = self.frontiter {
-                if let elt@Some(_) = inner.next() { return elt }
-            }
-            match self.iter.next() {
-                None => return self.backiter.as_mut().and_then(|it| it.next()),
-                Some(inner) => self.frontiter = Some(inner.into_iter()),
-            }
-        }
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (flo, fhi) = self.frontiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
-        let (blo, bhi) = self.backiter.as_ref().map_or((0, Some(0)), |it| it.size_hint());
-        let lo = flo.saturating_add(blo);
-        match (self.iter.size_hint(), fhi, bhi) {
-            ((0, Some(0)), Some(a), Some(b)) => (lo, a.checked_add(b)),
-            _ => (lo, None)
-        }
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if let Some(ref mut front) = self.frontiter {
-            init = front.try_fold(init, &mut fold)?;
-        }
-        self.frontiter = None;
-
-        {
-            let frontiter = &mut self.frontiter;
-            init = self.iter.try_fold(init, |acc, x| {
-                let mut mid = x.into_iter();
-                let r = mid.try_fold(acc, &mut fold);
-                *frontiter = Some(mid);
-                r
-            })?;
-        }
-        self.frontiter = None;
-
-        if let Some(ref mut back) = self.backiter {
-            init = back.try_fold(init, &mut fold)?;
-        }
-        self.backiter = None;
-
-        Try::from_ok(init)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.frontiter.into_iter()
-            .chain(self.iter.map(IntoIterator::into_iter))
-            .chain(self.backiter)
-            .fold(init, |acc, iter| iter.fold(acc, &mut fold))
-    }
-}
-
-impl<I, U> DoubleEndedIterator for FlattenCompat<I, U>
-    where I: DoubleEndedIterator, U: DoubleEndedIterator,
-          I::Item: IntoIterator<IntoIter = U, Item = U::Item>
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<U::Item> {
-        loop {
-            if let Some(ref mut inner) = self.backiter {
-                if let elt@Some(_) = inner.next_back() { return elt }
-            }
-            match self.iter.next_back() {
-                None => return self.frontiter.as_mut().and_then(|it| it.next_back()),
-                next => self.backiter = next.map(IntoIterator::into_iter),
-            }
-        }
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, mut init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if let Some(ref mut back) = self.backiter {
-            init = back.try_rfold(init, &mut fold)?;
-        }
-        self.backiter = None;
-
-        {
-            let backiter = &mut self.backiter;
-            init = self.iter.try_rfold(init, |acc, x| {
-                let mut mid = x.into_iter();
-                let r = mid.try_rfold(acc, &mut fold);
-                *backiter = Some(mid);
-                r
-            })?;
-        }
-        self.backiter = None;
-
-        if let Some(ref mut front) = self.frontiter {
-            init = front.try_rfold(init, &mut fold)?;
-        }
-        self.frontiter = None;
-
-        Try::from_ok(init)
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.frontiter.into_iter()
-            .chain(self.iter.map(IntoIterator::into_iter))
-            .chain(self.backiter)
-            .rfold(init, |acc, iter| iter.rfold(acc, &mut fold))
-    }
-}
-
-/// An iterator that yields `None` forever after the underlying iterator
-/// yields `None` once.
-///
-/// This `struct` is created by the [`fuse`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`fuse`]: trait.Iterator.html#method.fuse
-/// [`Iterator`]: trait.Iterator.html
-#[derive(Clone, Debug)]
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Fuse<I> {
-    iter: I,
-    done: bool
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> FusedIterator for Fuse<I> where I: Iterator {}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> Iterator for Fuse<I> where I: Iterator {
-    type Item = <I as Iterator>::Item;
-
-    #[inline]
-    default fn next(&mut self) -> Option<<I as Iterator>::Item> {
-        if self.done {
-            None
-        } else {
-            let next = self.iter.next();
-            self.done = next.is_none();
-            next
-        }
-    }
-
-    #[inline]
-    default fn nth(&mut self, n: usize) -> Option<I::Item> {
-        if self.done {
-            None
-        } else {
-            let nth = self.iter.nth(n);
-            self.done = nth.is_none();
-            nth
-        }
-    }
-
-    #[inline]
-    default fn last(self) -> Option<I::Item> {
-        if self.done {
-            None
-        } else {
-            self.iter.last()
-        }
-    }
-
-    #[inline]
-    default fn count(self) -> usize {
-        if self.done {
-            0
-        } else {
-            self.iter.count()
-        }
-    }
-
-    #[inline]
-    default fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.done {
-            (0, Some(0))
-        } else {
-            self.iter.size_hint()
-        }
-    }
-
-    #[inline]
-    default fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if self.done {
-            Try::from_ok(init)
-        } else {
-            let acc = self.iter.try_fold(init, fold)?;
-            self.done = true;
-            Try::from_ok(acc)
-        }
-    }
-
-    #[inline]
-    default fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        if self.done {
-            init
-        } else {
-            self.iter.fold(init, fold)
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> DoubleEndedIterator for Fuse<I> where I: DoubleEndedIterator {
-    #[inline]
-    default fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
-        if self.done {
-            None
-        } else {
-            let next = self.iter.next_back();
-            self.done = next.is_none();
-            next
-        }
-    }
-
-    #[inline]
-    default fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        if self.done {
-            Try::from_ok(init)
-        } else {
-            let acc = self.iter.try_rfold(init, fold)?;
-            self.done = true;
-            Try::from_ok(acc)
-        }
-    }
-
-    #[inline]
-    default fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        if self.done {
-            init
-        } else {
-            self.iter.rfold(init, fold)
-        }
-    }
-}
-
-unsafe impl<I> TrustedRandomAccess for Fuse<I>
-    where I: TrustedRandomAccess,
-{
-    unsafe fn get_unchecked(&mut self, i: usize) -> I::Item {
-        self.iter.get_unchecked(i)
-    }
-
-    fn may_have_side_effect() -> bool {
-        I::may_have_side_effect()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> Iterator for Fuse<I> where I: FusedIterator {
-    #[inline]
-    fn next(&mut self) -> Option<<I as Iterator>::Item> {
-        self.iter.next()
-    }
-
-    #[inline]
-    fn nth(&mut self, n: usize) -> Option<I::Item> {
-        self.iter.nth(n)
-    }
-
-    #[inline]
-    fn last(self) -> Option<I::Item> {
-        self.iter.last()
-    }
-
-    #[inline]
-    fn count(self) -> usize {
-        self.iter.count()
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.iter.try_fold(init, fold)
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.iter.fold(init, fold)
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I> DoubleEndedIterator for Fuse<I>
-    where I: DoubleEndedIterator + FusedIterator
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<<I as Iterator>::Item> {
-        self.iter.next_back()
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        self.iter.try_rfold(init, fold)
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        self.iter.rfold(init, fold)
-    }
-}
-
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I> ExactSizeIterator for Fuse<I> where I: ExactSizeIterator {
-    fn len(&self) -> usize {
-        self.iter.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-/// An iterator that calls a function with a reference to each element before
-/// yielding it.
-///
-/// This `struct` is created by the [`inspect`] method on [`Iterator`]. See its
-/// documentation for more.
-///
-/// [`inspect`]: trait.Iterator.html#method.inspect
-/// [`Iterator`]: trait.Iterator.html
-#[must_use = "iterators are lazy and do nothing unless consumed"]
-#[stable(feature = "rust1", since = "1.0.0")]
-#[derive(Clone)]
-pub struct Inspect<I, F> {
-    iter: I,
-    f: F,
-}
-
-#[stable(feature = "core_impl_debug", since = "1.9.0")]
-impl<I: fmt::Debug, F> fmt::Debug for Inspect<I, F> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Inspect")
-            .field("iter", &self.iter)
-            .finish()
-    }
-}
-
-impl<I: Iterator, F> Inspect<I, F> where F: FnMut(&I::Item) {
-    #[inline]
-    fn do_inspect(&mut self, elt: Option<I::Item>) -> Option<I::Item> {
-        if let Some(ref a) = elt {
-            (self.f)(a);
-        }
-
-        elt
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator, F> Iterator for Inspect<I, F> where F: FnMut(&I::Item) {
-    type Item = I::Item;
-
-    #[inline]
-    fn next(&mut self) -> Option<I::Item> {
-        let next = self.iter.next();
-        self.do_inspect(next)
-    }
-
-    #[inline]
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        self.iter.size_hint()
-    }
-
-    #[inline]
-    fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_fold(init, move |acc, item| { f(&item); fold(acc, item) })
-    }
-
-    #[inline]
-    fn fold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.fold(init, move |acc, item| { f(&item); fold(acc, item) })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: DoubleEndedIterator, F> DoubleEndedIterator for Inspect<I, F>
-    where F: FnMut(&I::Item),
-{
-    #[inline]
-    fn next_back(&mut self) -> Option<I::Item> {
-        let next = self.iter.next_back();
-        self.do_inspect(next)
-    }
-
-    #[inline]
-    fn try_rfold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R where
-        Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
-    {
-        let f = &mut self.f;
-        self.iter.try_rfold(init, move |acc, item| { f(&item); fold(acc, item) })
-    }
-
-    #[inline]
-    fn rfold<Acc, Fold>(self, init: Acc, mut fold: Fold) -> Acc
-        where Fold: FnMut(Acc, Self::Item) -> Acc,
-    {
-        let mut f = self.f;
-        self.iter.rfold(init, move |acc, item| { f(&item); fold(acc, item) })
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: ExactSizeIterator, F> ExactSizeIterator for Inspect<I, F>
-    where F: FnMut(&I::Item)
-{
-    fn len(&self) -> usize {
-        self.iter.len()
-    }
-
-    fn is_empty(&self) -> bool {
-        self.iter.is_empty()
-    }
-}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I: FusedIterator, F> FusedIterator for Inspect<I, F>
-    where F: FnMut(&I::Item) {}
diff --git a/src/libcore/iter/range.rs b/src/libcore/iter/range.rs
index 66c09a0ddd0fb..a3e9cfa949312 100644
--- a/src/libcore/iter/range.rs
+++ b/src/libcore/iter/range.rs
@@ -20,19 +20,19 @@ pub trait Step: Clone + PartialOrd + Sized {
     /// without overflow.
     fn steps_between(start: &Self, end: &Self) -> Option<usize>;
 
-    /// Replaces this step with `1`, returning itself
+    /// Replaces this step with `1`, returning itself.
     fn replace_one(&mut self) -> Self;
 
-    /// Replaces this step with `0`, returning itself
+    /// Replaces this step with `0`, returning itself.
     fn replace_zero(&mut self) -> Self;
 
-    /// Adds one to this step, returning the result
+    /// Adds one to this step, returning the result.
     fn add_one(&self) -> Self;
 
-    /// Subtracts one to this step, returning the result
+    /// Subtracts one to this step, returning the result.
     fn sub_one(&self) -> Self;
 
-    /// Add an usize, returning None on overflow
+    /// Adds a `usize`, returning `None` on overflow.
     fn add_usize(&self, n: usize) -> Option<Self>;
 }
 
diff --git a/src/libcore/iter/sources.rs b/src/libcore/iter/sources.rs
index 2590fa6023a53..74ff7f41d76fa 100644
--- a/src/libcore/iter/sources.rs
+++ b/src/libcore/iter/sources.rs
@@ -491,24 +491,22 @@ pub fn once_with<A, F: FnOnce() -> A>(gen: F) -> OnceWith<F> {
 }
 
 /// Creates a new iterator where each iteration calls the provided closure
-/// `F: FnMut(&mut St) -> Option<T>`.
+/// `F: FnMut() -> Option<T>`.
 ///
 /// This allows creating a custom iterator with any behavior
 /// without using the more verbose syntax of creating a dedicated type
 /// and implementing the `Iterator` trait for it.
 ///
-/// In addition to its captures and environment,
-/// the closure is given a mutable reference to some state
-/// that is preserved across iterations.
-/// That state starts as the given `initial_state` value.
-///
-/// Note that the `Unfold` iterator doesn’t make assumptions about the behavior of the closure,
+/// Note that the `FromFn` iterator doesn’t make assumptions about the behavior of the closure,
 /// and therefore conservatively does not implement [`FusedIterator`],
 /// or override [`Iterator::size_hint`] from its default `(0, None)`.
 ///
 /// [`FusedIterator`]: trait.FusedIterator.html
 /// [`Iterator::size_hint`]: trait.Iterator.html#method.size_hint
 ///
+/// The closure can use captures and its environment to track state across iterations. Depending on
+/// how the iterator is used, this may require specifying the `move` keyword on the closure.
+///
 /// # Examples
 ///
 /// Let’s re-implement the counter iterator from [module-level documentation]:
@@ -516,14 +514,14 @@ pub fn once_with<A, F: FnOnce() -> A>(gen: F) -> OnceWith<F> {
 /// [module-level documentation]: index.html
 ///
 /// ```
-/// #![feature(iter_unfold)]
-/// let counter = std::iter::unfold(0, |count| {
+/// let mut count = 0;
+/// let counter = std::iter::from_fn(move || {
 ///     // Increment our count. This is why we started at zero.
-///     *count += 1;
+///     count += 1;
 ///
 ///     // Check to see if we've finished counting or not.
-///     if *count < 6 {
-///         Some(*count)
+///     if count < 6 {
+///         Some(count)
 ///     } else {
 ///         None
 ///     }
@@ -531,47 +529,39 @@ pub fn once_with<A, F: FnOnce() -> A>(gen: F) -> OnceWith<F> {
 /// assert_eq!(counter.collect::<Vec<_>>(), &[1, 2, 3, 4, 5]);
 /// ```
 #[inline]
-#[unstable(feature = "iter_unfold", issue = "55977")]
-pub fn unfold<St, T, F>(initial_state: St, f: F) -> Unfold<St, F>
-    where F: FnMut(&mut St) -> Option<T>
+#[stable(feature = "iter_from_fn", since = "1.34.0")]
+pub fn from_fn<T, F>(f: F) -> FromFn<F>
+    where F: FnMut() -> Option<T>
 {
-    Unfold {
-        state: initial_state,
-        f,
-    }
+    FromFn(f)
 }
 
-/// An iterator where each iteration calls the provided closure `F: FnMut(&mut St) -> Option<T>`.
+/// An iterator where each iteration calls the provided closure `F: FnMut() -> Option<T>`.
 ///
-/// This `struct` is created by the [`unfold`] function.
+/// This `struct` is created by the [`iter::from_fn`] function.
 /// See its documentation for more.
 ///
-/// [`unfold`]: fn.unfold.html
+/// [`iter::from_fn`]: fn.from_fn.html
 #[derive(Clone)]
-#[unstable(feature = "iter_unfold", issue = "55977")]
-pub struct Unfold<St, F> {
-    state: St,
-    f: F,
-}
+#[stable(feature = "iter_from_fn", since = "1.34.0")]
+pub struct FromFn<F>(F);
 
-#[unstable(feature = "iter_unfold", issue = "55977")]
-impl<St, T, F> Iterator for Unfold<St, F>
-    where F: FnMut(&mut St) -> Option<T>
+#[stable(feature = "iter_from_fn", since = "1.34.0")]
+impl<T, F> Iterator for FromFn<F>
+    where F: FnMut() -> Option<T>
 {
     type Item = T;
 
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {
-        (self.f)(&mut self.state)
+        (self.0)()
     }
 }
 
-#[unstable(feature = "iter_unfold", issue = "55977")]
-impl<St: fmt::Debug, F> fmt::Debug for Unfold<St, F> {
+#[stable(feature = "iter_from_fn", since = "1.34.0")]
+impl<F> fmt::Debug for FromFn<F> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Unfold")
-            .field("state", &self.state)
-            .finish()
+        f.debug_struct("FromFn").finish()
     }
 }
 
@@ -581,13 +571,12 @@ impl<St: fmt::Debug, F> fmt::Debug for Unfold<St, F> {
 /// and calls the given `FnMut(&T) -> Option<T>` closure to compute each item’s successor.
 ///
 /// ```
-/// #![feature(iter_unfold)]
 /// use std::iter::successors;
 ///
 /// let powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10));
 /// assert_eq!(powers_of_10.collect::<Vec<_>>(), &[1, 10, 100, 1_000, 10_000]);
 /// ```
-#[unstable(feature = "iter_unfold", issue = "55977")]
+#[stable(feature = "iter_successors", since = "1.34.0")]
 pub fn successors<T, F>(first: Option<T>, succ: F) -> Successors<T, F>
     where F: FnMut(&T) -> Option<T>
 {
@@ -607,13 +596,13 @@ pub fn successors<T, F>(first: Option<T>, succ: F) -> Successors<T, F>
 ///
 /// [`successors`]: fn.successors.html
 #[derive(Clone)]
-#[unstable(feature = "iter_unfold", issue = "55977")]
+#[stable(feature = "iter_successors", since = "1.34.0")]
 pub struct Successors<T, F> {
     next: Option<T>,
     succ: F,
 }
 
-#[unstable(feature = "iter_unfold", issue = "55977")]
+#[stable(feature = "iter_successors", since = "1.34.0")]
 impl<T, F> Iterator for Successors<T, F>
     where F: FnMut(&T) -> Option<T>
 {
@@ -637,12 +626,12 @@ impl<T, F> Iterator for Successors<T, F>
     }
 }
 
-#[unstable(feature = "iter_unfold", issue = "55977")]
+#[stable(feature = "iter_successors", since = "1.34.0")]
 impl<T, F> FusedIterator for Successors<T, F>
     where F: FnMut(&T) -> Option<T>
 {}
 
-#[unstable(feature = "iter_unfold", issue = "55977")]
+#[stable(feature = "iter_successors", since = "1.34.0")]
 impl<T: fmt::Debug, F> fmt::Debug for Successors<T, F> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("Successors")
diff --git a/src/libcore/iter/traits.rs b/src/libcore/iter/traits.rs
deleted file mode 100644
index e8c6cd8b79c72..0000000000000
--- a/src/libcore/iter/traits.rs
+++ /dev/null
@@ -1,1060 +0,0 @@
-use ops::{Mul, Add, Try};
-use num::Wrapping;
-
-use super::LoopState;
-
-/// Conversion from an `Iterator`.
-///
-/// By implementing `FromIterator` for a type, you define how it will be
-/// created from an iterator. This is common for types which describe a
-/// collection of some kind.
-///
-/// `FromIterator`'s [`from_iter`] is rarely called explicitly, and is instead
-/// used through [`Iterator`]'s [`collect`] method. See [`collect`]'s
-/// documentation for more examples.
-///
-/// [`from_iter`]: #tymethod.from_iter
-/// [`Iterator`]: trait.Iterator.html
-/// [`collect`]: trait.Iterator.html#method.collect
-///
-/// See also: [`IntoIterator`].
-///
-/// [`IntoIterator`]: trait.IntoIterator.html
-///
-/// # Examples
-///
-/// Basic usage:
-///
-/// ```
-/// use std::iter::FromIterator;
-///
-/// let five_fives = std::iter::repeat(5).take(5);
-///
-/// let v = Vec::from_iter(five_fives);
-///
-/// assert_eq!(v, vec![5, 5, 5, 5, 5]);
-/// ```
-///
-/// Using [`collect`] to implicitly use `FromIterator`:
-///
-/// ```
-/// let five_fives = std::iter::repeat(5).take(5);
-///
-/// let v: Vec<i32> = five_fives.collect();
-///
-/// assert_eq!(v, vec![5, 5, 5, 5, 5]);
-/// ```
-///
-/// Implementing `FromIterator` for your type:
-///
-/// ```
-/// use std::iter::FromIterator;
-///
-/// // A sample collection, that's just a wrapper over Vec<T>
-/// #[derive(Debug)]
-/// struct MyCollection(Vec<i32>);
-///
-/// // Let's give it some methods so we can create one and add things
-/// // to it.
-/// impl MyCollection {
-///     fn new() -> MyCollection {
-///         MyCollection(Vec::new())
-///     }
-///
-///     fn add(&mut self, elem: i32) {
-///         self.0.push(elem);
-///     }
-/// }
-///
-/// // and we'll implement FromIterator
-/// impl FromIterator<i32> for MyCollection {
-///     fn from_iter<I: IntoIterator<Item=i32>>(iter: I) -> Self {
-///         let mut c = MyCollection::new();
-///
-///         for i in iter {
-///             c.add(i);
-///         }
-///
-///         c
-///     }
-/// }
-///
-/// // Now we can make a new iterator...
-/// let iter = (0..5).into_iter();
-///
-/// // ... and make a MyCollection out of it
-/// let c = MyCollection::from_iter(iter);
-///
-/// assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
-///
-/// // collect works too!
-///
-/// let iter = (0..5).into_iter();
-/// let c: MyCollection = iter.collect();
-///
-/// assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented(
-    message="a collection of type `{Self}` cannot be built from an iterator \
-             over elements of type `{A}`",
-    label="a collection of type `{Self}` cannot be built from `std::iter::Iterator<Item={A}>`",
-)]
-pub trait FromIterator<A>: Sized {
-    /// Creates a value from an iterator.
-    ///
-    /// See the [module-level documentation] for more.
-    ///
-    /// [module-level documentation]: index.html
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// use std::iter::FromIterator;
-    ///
-    /// let five_fives = std::iter::repeat(5).take(5);
-    ///
-    /// let v = Vec::from_iter(five_fives);
-    ///
-    /// assert_eq!(v, vec![5, 5, 5, 5, 5]);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn from_iter<T: IntoIterator<Item=A>>(iter: T) -> Self;
-}
-
-/// Conversion into an `Iterator`.
-///
-/// By implementing `IntoIterator` for a type, you define how it will be
-/// converted to an iterator. This is common for types which describe a
-/// collection of some kind.
-///
-/// One benefit of implementing `IntoIterator` is that your type will [work
-/// with Rust's `for` loop syntax](index.html#for-loops-and-intoiterator).
-///
-/// See also: [`FromIterator`].
-///
-/// [`FromIterator`]: trait.FromIterator.html
-///
-/// # Examples
-///
-/// Basic usage:
-///
-/// ```
-/// let v = vec![1, 2, 3];
-/// let mut iter = v.into_iter();
-///
-/// assert_eq!(Some(1), iter.next());
-/// assert_eq!(Some(2), iter.next());
-/// assert_eq!(Some(3), iter.next());
-/// assert_eq!(None, iter.next());
-/// ```
-/// Implementing `IntoIterator` for your type:
-///
-/// ```
-/// // A sample collection, that's just a wrapper over Vec<T>
-/// #[derive(Debug)]
-/// struct MyCollection(Vec<i32>);
-///
-/// // Let's give it some methods so we can create one and add things
-/// // to it.
-/// impl MyCollection {
-///     fn new() -> MyCollection {
-///         MyCollection(Vec::new())
-///     }
-///
-///     fn add(&mut self, elem: i32) {
-///         self.0.push(elem);
-///     }
-/// }
-///
-/// // and we'll implement IntoIterator
-/// impl IntoIterator for MyCollection {
-///     type Item = i32;
-///     type IntoIter = ::std::vec::IntoIter<i32>;
-///
-///     fn into_iter(self) -> Self::IntoIter {
-///         self.0.into_iter()
-///     }
-/// }
-///
-/// // Now we can make a new collection...
-/// let mut c = MyCollection::new();
-///
-/// // ... add some stuff to it ...
-/// c.add(0);
-/// c.add(1);
-/// c.add(2);
-///
-/// // ... and then turn it into an Iterator:
-/// for (i, n) in c.into_iter().enumerate() {
-///     assert_eq!(i as i32, n);
-/// }
-/// ```
-///
-/// It is common to use `IntoIterator` as a trait bound. This allows
-/// the input collection type to change, so long as it is still an
-/// iterator. Additional bounds can be specified by restricting on
-/// `Item`:
-///
-/// ```rust
-/// fn collect_as_strings<T>(collection: T) -> Vec<String>
-///     where T: IntoIterator,
-///           T::Item : std::fmt::Debug,
-/// {
-///     collection
-///         .into_iter()
-///         .map(|item| format!("{:?}", item))
-///         .collect()
-/// }
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-pub trait IntoIterator {
-    /// The type of the elements being iterated over.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    type Item;
-
-    /// Which kind of iterator are we turning this into?
-    #[stable(feature = "rust1", since = "1.0.0")]
-    type IntoIter: Iterator<Item=Self::Item>;
-
-    /// Creates an iterator from a value.
-    ///
-    /// See the [module-level documentation] for more.
-    ///
-    /// [module-level documentation]: index.html
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let v = vec![1, 2, 3];
-    /// let mut iter = v.into_iter();
-    ///
-    /// assert_eq!(Some(1), iter.next());
-    /// assert_eq!(Some(2), iter.next());
-    /// assert_eq!(Some(3), iter.next());
-    /// assert_eq!(None, iter.next());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn into_iter(self) -> Self::IntoIter;
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator> IntoIterator for I {
-    type Item = I::Item;
-    type IntoIter = I;
-
-    fn into_iter(self) -> I {
-        self
-    }
-}
-
-/// Extend a collection with the contents of an iterator.
-///
-/// Iterators produce a series of values, and collections can also be thought
-/// of as a series of values. The `Extend` trait bridges this gap, allowing you
-/// to extend a collection by including the contents of that iterator. When
-/// extending a collection with an already existing key, that entry is updated
-/// or, in the case of collections that permit multiple entries with equal
-/// keys, that entry is inserted.
-///
-/// # Examples
-///
-/// Basic usage:
-///
-/// ```
-/// // You can extend a String with some chars:
-/// let mut message = String::from("The first three letters are: ");
-///
-/// message.extend(&['a', 'b', 'c']);
-///
-/// assert_eq!("abc", &message[29..32]);
-/// ```
-///
-/// Implementing `Extend`:
-///
-/// ```
-/// // A sample collection, that's just a wrapper over Vec<T>
-/// #[derive(Debug)]
-/// struct MyCollection(Vec<i32>);
-///
-/// // Let's give it some methods so we can create one and add things
-/// // to it.
-/// impl MyCollection {
-///     fn new() -> MyCollection {
-///         MyCollection(Vec::new())
-///     }
-///
-///     fn add(&mut self, elem: i32) {
-///         self.0.push(elem);
-///     }
-/// }
-///
-/// // since MyCollection has a list of i32s, we implement Extend for i32
-/// impl Extend<i32> for MyCollection {
-///
-///     // This is a bit simpler with the concrete type signature: we can call
-///     // extend on anything which can be turned into an Iterator which gives
-///     // us i32s. Because we need i32s to put into MyCollection.
-///     fn extend<T: IntoIterator<Item=i32>>(&mut self, iter: T) {
-///
-///         // The implementation is very straightforward: loop through the
-///         // iterator, and add() each element to ourselves.
-///         for elem in iter {
-///             self.add(elem);
-///         }
-///     }
-/// }
-///
-/// let mut c = MyCollection::new();
-///
-/// c.add(5);
-/// c.add(6);
-/// c.add(7);
-///
-/// // let's extend our collection with three more numbers
-/// c.extend(vec![1, 2, 3]);
-///
-/// // we've added these elements onto the end
-/// assert_eq!("MyCollection([5, 6, 7, 1, 2, 3])", format!("{:?}", c));
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-pub trait Extend<A> {
-    /// Extends a collection with the contents of an iterator.
-    ///
-    /// As this is the only method for this trait, the [trait-level] docs
-    /// contain more details.
-    ///
-    /// [trait-level]: trait.Extend.html
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// // You can extend a String with some chars:
-    /// let mut message = String::from("abc");
-    ///
-    /// message.extend(['d', 'e', 'f'].iter());
-    ///
-    /// assert_eq!("abcdef", &message);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn extend<T: IntoIterator<Item=A>>(&mut self, iter: T);
-}
-
-#[stable(feature = "extend_for_unit", since = "1.28.0")]
-impl Extend<()> for () {
-    fn extend<T: IntoIterator<Item = ()>>(&mut self, iter: T) {
-        iter.into_iter().for_each(drop)
-    }
-}
-
-/// An iterator able to yield elements from both ends.
-///
-/// Something that implements `DoubleEndedIterator` has one extra capability
-/// over something that implements [`Iterator`]: the ability to also take
-/// `Item`s from the back, as well as the front.
-///
-/// It is important to note that both back and forth work on the same range,
-/// and do not cross: iteration is over when they meet in the middle.
-///
-/// In a similar fashion to the [`Iterator`] protocol, once a
-/// `DoubleEndedIterator` returns `None` from a `next_back()`, calling it again
-/// may or may not ever return `Some` again. `next()` and `next_back()` are
-/// interchangeable for this purpose.
-///
-/// [`Iterator`]: trait.Iterator.html
-///
-/// # Examples
-///
-/// Basic usage:
-///
-/// ```
-/// let numbers = vec![1, 2, 3, 4, 5, 6];
-///
-/// let mut iter = numbers.iter();
-///
-/// assert_eq!(Some(&1), iter.next());
-/// assert_eq!(Some(&6), iter.next_back());
-/// assert_eq!(Some(&5), iter.next_back());
-/// assert_eq!(Some(&2), iter.next());
-/// assert_eq!(Some(&3), iter.next());
-/// assert_eq!(Some(&4), iter.next());
-/// assert_eq!(None, iter.next());
-/// assert_eq!(None, iter.next_back());
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-pub trait DoubleEndedIterator: Iterator {
-    /// Removes and returns an element from the end of the iterator.
-    ///
-    /// Returns `None` when there are no more elements.
-    ///
-    /// The [trait-level] docs contain more details.
-    ///
-    /// [trait-level]: trait.DoubleEndedIterator.html
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let numbers = vec![1, 2, 3, 4, 5, 6];
-    ///
-    /// let mut iter = numbers.iter();
-    ///
-    /// assert_eq!(Some(&1), iter.next());
-    /// assert_eq!(Some(&6), iter.next_back());
-    /// assert_eq!(Some(&5), iter.next_back());
-    /// assert_eq!(Some(&2), iter.next());
-    /// assert_eq!(Some(&3), iter.next());
-    /// assert_eq!(Some(&4), iter.next());
-    /// assert_eq!(None, iter.next());
-    /// assert_eq!(None, iter.next_back());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn next_back(&mut self) -> Option<Self::Item>;
-
-    /// Returns the `n`th element from the end of the iterator.
-    ///
-    /// This is essentially the reversed version of [`nth`]. Although like most indexing
-    /// operations, the count starts from zero, so `nth_back(0)` returns the first value fro
-    /// the end, `nth_back(1)` the second, and so on.
-    ///
-    /// Note that all elements between the end and the returned element will be
-    /// consumed, including the returned element. This also means that calling
-    /// `nth_back(0)` multiple times on the same iterator will return different
-    /// elements.
-    ///
-    /// `nth_back()` will return [`None`] if `n` is greater than or equal to the length of the
-    /// iterator.
-    ///
-    /// [`None`]: ../../std/option/enum.Option.html#variant.None
-    /// [`nth`]: ../../std/iter/trait.Iterator.html#method.nth
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// #![feature(iter_nth_back)]
-    /// let a = [1, 2, 3];
-    /// assert_eq!(a.iter().nth_back(2), Some(&1));
-    /// ```
-    ///
-    /// Calling `nth_back()` multiple times doesn't rewind the iterator:
-    ///
-    /// ```
-    /// #![feature(iter_nth_back)]
-    /// let a = [1, 2, 3];
-    ///
-    /// let mut iter = a.iter();
-    ///
-    /// assert_eq!(iter.nth_back(1), Some(&2));
-    /// assert_eq!(iter.nth_back(1), None);
-    /// ```
-    ///
-    /// Returning `None` if there are less than `n + 1` elements:
-    ///
-    /// ```
-    /// #![feature(iter_nth_back)]
-    /// let a = [1, 2, 3];
-    /// assert_eq!(a.iter().nth_back(10), None);
-    /// ```
-    #[inline]
-    #[unstable(feature = "iter_nth_back", issue = "56995")]
-    fn nth_back(&mut self, mut n: usize) -> Option<Self::Item> {
-        for x in self.rev() {
-            if n == 0 { return Some(x) }
-            n -= 1;
-        }
-        None
-    }
-
-    /// This is the reverse version of [`try_fold()`]: it takes elements
-    /// starting from the back of the iterator.
-    ///
-    /// [`try_fold()`]: trait.Iterator.html#method.try_fold
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let a = ["1", "2", "3"];
-    /// let sum = a.iter()
-    ///     .map(|&s| s.parse::<i32>())
-    ///     .try_rfold(0, |acc, x| x.and_then(|y| Ok(acc + y)));
-    /// assert_eq!(sum, Ok(6));
-    /// ```
-    ///
-    /// Short-circuiting:
-    ///
-    /// ```
-    /// let a = ["1", "rust", "3"];
-    /// let mut it = a.iter();
-    /// let sum = it
-    ///     .by_ref()
-    ///     .map(|&s| s.parse::<i32>())
-    ///     .try_rfold(0, |acc, x| x.and_then(|y| Ok(acc + y)));
-    /// assert!(sum.is_err());
-    ///
-    /// // Because it short-circuited, the remaining elements are still
-    /// // available through the iterator.
-    /// assert_eq!(it.next_back(), Some(&"1"));
-    /// ```
-    #[inline]
-    #[stable(feature = "iterator_try_fold", since = "1.27.0")]
-    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R
-    where
-        Self: Sized,
-        F: FnMut(B, Self::Item) -> R,
-        R: Try<Ok=B>
-    {
-        let mut accum = init;
-        while let Some(x) = self.next_back() {
-            accum = f(accum, x)?;
-        }
-        Try::from_ok(accum)
-    }
-
-    /// An iterator method that reduces the iterator's elements to a single,
-    /// final value, starting from the back.
-    ///
-    /// This is the reverse version of [`fold()`]: it takes elements starting from
-    /// the back of the iterator.
-    ///
-    /// `rfold()` takes two arguments: an initial value, and a closure with two
-    /// arguments: an 'accumulator', and an element. The closure returns the value that
-    /// the accumulator should have for the next iteration.
-    ///
-    /// The initial value is the value the accumulator will have on the first
-    /// call.
-    ///
-    /// After applying this closure to every element of the iterator, `rfold()`
-    /// returns the accumulator.
-    ///
-    /// This operation is sometimes called 'reduce' or 'inject'.
-    ///
-    /// Folding is useful whenever you have a collection of something, and want
-    /// to produce a single value from it.
-    ///
-    /// [`fold()`]: trait.Iterator.html#method.fold
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let a = [1, 2, 3];
-    ///
-    /// // the sum of all of the elements of a
-    /// let sum = a.iter()
-    ///            .rfold(0, |acc, &x| acc + x);
-    ///
-    /// assert_eq!(sum, 6);
-    /// ```
-    ///
-    /// This example builds a string, starting with an initial value
-    /// and continuing with each element from the back until the front:
-    ///
-    /// ```
-    /// let numbers = [1, 2, 3, 4, 5];
-    ///
-    /// let zero = "0".to_string();
-    ///
-    /// let result = numbers.iter().rfold(zero, |acc, &x| {
-    ///     format!("({} + {})", x, acc)
-    /// });
-    ///
-    /// assert_eq!(result, "(1 + (2 + (3 + (4 + (5 + 0)))))");
-    /// ```
-    #[inline]
-    #[stable(feature = "iter_rfold", since = "1.27.0")]
-    fn rfold<B, F>(mut self, accum: B, mut f: F) -> B
-    where
-        Self: Sized,
-        F: FnMut(B, Self::Item) -> B,
-    {
-        self.try_rfold(accum, move |acc, x| Ok::<B, !>(f(acc, x))).unwrap()
-    }
-
-    /// Searches for an element of an iterator from the back that satisfies a predicate.
-    ///
-    /// `rfind()` takes a closure that returns `true` or `false`. It applies
-    /// this closure to each element of the iterator, starting at the end, and if any
-    /// of them return `true`, then `rfind()` returns [`Some(element)`]. If they all return
-    /// `false`, it returns [`None`].
-    ///
-    /// `rfind()` is short-circuiting; in other words, it will stop processing
-    /// as soon as the closure returns `true`.
-    ///
-    /// Because `rfind()` takes a reference, and many iterators iterate over
-    /// references, this leads to a possibly confusing situation where the
-    /// argument is a double reference. You can see this effect in the
-    /// examples below, with `&&x`.
-    ///
-    /// [`Some(element)`]: ../../std/option/enum.Option.html#variant.Some
-    /// [`None`]: ../../std/option/enum.Option.html#variant.None
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// let a = [1, 2, 3];
-    ///
-    /// assert_eq!(a.iter().rfind(|&&x| x == 2), Some(&2));
-    ///
-    /// assert_eq!(a.iter().rfind(|&&x| x == 5), None);
-    /// ```
-    ///
-    /// Stopping at the first `true`:
-    ///
-    /// ```
-    /// let a = [1, 2, 3];
-    ///
-    /// let mut iter = a.iter();
-    ///
-    /// assert_eq!(iter.rfind(|&&x| x == 2), Some(&2));
-    ///
-    /// // we can still use `iter`, as there are more elements.
-    /// assert_eq!(iter.next_back(), Some(&1));
-    /// ```
-    #[inline]
-    #[stable(feature = "iter_rfind", since = "1.27.0")]
-    fn rfind<P>(&mut self, mut predicate: P) -> Option<Self::Item>
-    where
-        Self: Sized,
-        P: FnMut(&Self::Item) -> bool
-    {
-        self.try_rfold((), move |(), x| {
-            if predicate(&x) { LoopState::Break(x) }
-            else { LoopState::Continue(()) }
-        }).break_value()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for &'a mut I {
-    fn next_back(&mut self) -> Option<I::Item> {
-        (**self).next_back()
-    }
-    fn nth_back(&mut self, n: usize) -> Option<I::Item> {
-        (**self).nth_back(n)
-    }
-}
-
-/// An iterator that knows its exact length.
-///
-/// Many [`Iterator`]s don't know how many times they will iterate, but some do.
-/// If an iterator knows how many times it can iterate, providing access to
-/// that information can be useful. For example, if you want to iterate
-/// backwards, a good start is to know where the end is.
-///
-/// When implementing an `ExactSizeIterator`, you must also implement
-/// [`Iterator`]. When doing so, the implementation of [`size_hint`] *must*
-/// return the exact size of the iterator.
-///
-/// [`Iterator`]: trait.Iterator.html
-/// [`size_hint`]: trait.Iterator.html#method.size_hint
-///
-/// The [`len`] method has a default implementation, so you usually shouldn't
-/// implement it. However, you may be able to provide a more performant
-/// implementation than the default, so overriding it in this case makes sense.
-///
-/// [`len`]: #method.len
-///
-/// # Examples
-///
-/// Basic usage:
-///
-/// ```
-/// // a finite range knows exactly how many times it will iterate
-/// let five = 0..5;
-///
-/// assert_eq!(5, five.len());
-/// ```
-///
-/// In the [module level docs][moddocs], we implemented an [`Iterator`],
-/// `Counter`. Let's implement `ExactSizeIterator` for it as well:
-///
-/// [moddocs]: index.html
-///
-/// ```
-/// # struct Counter {
-/// #     count: usize,
-/// # }
-/// # impl Counter {
-/// #     fn new() -> Counter {
-/// #         Counter { count: 0 }
-/// #     }
-/// # }
-/// # impl Iterator for Counter {
-/// #     type Item = usize;
-/// #     fn next(&mut self) -> Option<usize> {
-/// #         self.count += 1;
-/// #         if self.count < 6 {
-/// #             Some(self.count)
-/// #         } else {
-/// #             None
-/// #         }
-/// #     }
-/// # }
-/// impl ExactSizeIterator for Counter {
-///     // We can easily calculate the remaining number of iterations.
-///     fn len(&self) -> usize {
-///         5 - self.count
-///     }
-/// }
-///
-/// // And now we can use it!
-///
-/// let counter = Counter::new();
-///
-/// assert_eq!(5, counter.len());
-/// ```
-#[stable(feature = "rust1", since = "1.0.0")]
-pub trait ExactSizeIterator: Iterator {
-    /// Returns the exact number of times the iterator will iterate.
-    ///
-    /// This method has a default implementation, so you usually should not
-    /// implement it directly. However, if you can provide a more efficient
-    /// implementation, you can do so. See the [trait-level] docs for an
-    /// example.
-    ///
-    /// This function has the same safety guarantees as the [`size_hint`]
-    /// function.
-    ///
-    /// [trait-level]: trait.ExactSizeIterator.html
-    /// [`size_hint`]: trait.Iterator.html#method.size_hint
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// // a finite range knows exactly how many times it will iterate
-    /// let five = 0..5;
-    ///
-    /// assert_eq!(5, five.len());
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn len(&self) -> usize {
-        let (lower, upper) = self.size_hint();
-        // Note: This assertion is overly defensive, but it checks the invariant
-        // guaranteed by the trait. If this trait were rust-internal,
-        // we could use debug_assert!; assert_eq! will check all Rust user
-        // implementations too.
-        assert_eq!(upper, Some(lower));
-        lower
-    }
-
-    /// Returns whether the iterator is empty.
-    ///
-    /// This method has a default implementation using `self.len()`, so you
-    /// don't need to implement it yourself.
-    ///
-    /// # Examples
-    ///
-    /// Basic usage:
-    ///
-    /// ```
-    /// #![feature(exact_size_is_empty)]
-    ///
-    /// let mut one_element = std::iter::once(0);
-    /// assert!(!one_element.is_empty());
-    ///
-    /// assert_eq!(one_element.next(), Some(0));
-    /// assert!(one_element.is_empty());
-    ///
-    /// assert_eq!(one_element.next(), None);
-    /// ```
-    #[inline]
-    #[unstable(feature = "exact_size_is_empty", issue = "35428")]
-    fn is_empty(&self) -> bool {
-        self.len() == 0
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for &mut I {
-    fn len(&self) -> usize {
-        (**self).len()
-    }
-    fn is_empty(&self) -> bool {
-        (**self).is_empty()
-    }
-}
-
-/// Trait to represent types that can be created by summing up an iterator.
-///
-/// This trait is used to implement the [`sum`] method on iterators. Types which
-/// implement the trait can be generated by the [`sum`] method. Like
-/// [`FromIterator`] this trait should rarely be called directly and instead
-/// interacted with through [`Iterator::sum`].
-///
-/// [`sum`]: ../../std/iter/trait.Sum.html#tymethod.sum
-/// [`FromIterator`]: ../../std/iter/trait.FromIterator.html
-/// [`Iterator::sum`]: ../../std/iter/trait.Iterator.html#method.sum
-#[stable(feature = "iter_arith_traits", since = "1.12.0")]
-pub trait Sum<A = Self>: Sized {
-    /// Method which takes an iterator and generates `Self` from the elements by
-    /// "summing up" the items.
-    #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-    fn sum<I: Iterator<Item=A>>(iter: I) -> Self;
-}
-
-/// Trait to represent types that can be created by multiplying elements of an
-/// iterator.
-///
-/// This trait is used to implement the [`product`] method on iterators. Types
-/// which implement the trait can be generated by the [`product`] method. Like
-/// [`FromIterator`] this trait should rarely be called directly and instead
-/// interacted with through [`Iterator::product`].
-///
-/// [`product`]: ../../std/iter/trait.Product.html#tymethod.product
-/// [`FromIterator`]: ../../std/iter/trait.FromIterator.html
-/// [`Iterator::product`]: ../../std/iter/trait.Iterator.html#method.product
-#[stable(feature = "iter_arith_traits", since = "1.12.0")]
-pub trait Product<A = Self>: Sized {
-    /// Method which takes an iterator and generates `Self` from the elements by
-    /// multiplying the items.
-    #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-    fn product<I: Iterator<Item=A>>(iter: I) -> Self;
-}
-
-// N.B., explicitly use Add and Mul here to inherit overflow checks
-macro_rules! integer_sum_product {
-    (@impls $zero:expr, $one:expr, #[$attr:meta], $($a:ty)*) => ($(
-        #[$attr]
-        impl Sum for $a {
-            fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
-                iter.fold($zero, Add::add)
-            }
-        }
-
-        #[$attr]
-        impl Product for $a {
-            fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
-                iter.fold($one, Mul::mul)
-            }
-        }
-
-        #[$attr]
-        impl<'a> Sum<&'a $a> for $a {
-            fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
-                iter.fold($zero, Add::add)
-            }
-        }
-
-        #[$attr]
-        impl<'a> Product<&'a $a> for $a {
-            fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
-                iter.fold($one, Mul::mul)
-            }
-        }
-    )*);
-    ($($a:ty)*) => (
-        integer_sum_product!(@impls 0, 1,
-                #[stable(feature = "iter_arith_traits", since = "1.12.0")],
-                $($a)+);
-        integer_sum_product!(@impls Wrapping(0), Wrapping(1),
-                #[stable(feature = "wrapping_iter_arith", since = "1.14.0")],
-                $(Wrapping<$a>)+);
-    );
-}
-
-macro_rules! float_sum_product {
-    ($($a:ident)*) => ($(
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-        impl Sum for $a {
-            fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
-                iter.fold(0.0, |a, b| a + b)
-            }
-        }
-
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-        impl Product for $a {
-            fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
-                iter.fold(1.0, |a, b| a * b)
-            }
-        }
-
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-        impl<'a> Sum<&'a $a> for $a {
-            fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
-                iter.fold(0.0, |a, b| a + *b)
-            }
-        }
-
-        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
-        impl<'a> Product<&'a $a> for $a {
-            fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
-                iter.fold(1.0, |a, b| a * *b)
-            }
-        }
-    )*)
-}
-
-integer_sum_product! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
-float_sum_product! { f32 f64 }
-
-/// An iterator adapter that produces output as long as the underlying
-/// iterator produces `Result::Ok` values.
-///
-/// If an error is encountered, the iterator stops and the error is
-/// stored. The error may be recovered later via `reconstruct`.
-struct ResultShunt<I, E> {
-    iter: I,
-    error: Option<E>,
-}
-
-impl<I, T, E> ResultShunt<I, E>
-    where I: Iterator<Item = Result<T, E>>
-{
-    /// Process the given iterator as if it yielded a `T` instead of a
-    /// `Result<T, _>`. Any errors will stop the inner iterator and
-    /// the overall result will be an error.
-    pub fn process<F, U>(iter: I, mut f: F) -> Result<U, E>
-        where F: FnMut(&mut Self) -> U
-    {
-        let mut shunt = ResultShunt::new(iter);
-        let value = f(shunt.by_ref());
-        shunt.reconstruct(value)
-    }
-
-    fn new(iter: I) -> Self {
-        ResultShunt {
-            iter,
-            error: None,
-        }
-    }
-
-    /// Consume the adapter and rebuild a `Result` value. This should
-    /// *always* be called, otherwise any potential error would be
-    /// lost.
-    fn reconstruct<U>(self, val: U) -> Result<U, E> {
-        match self.error {
-            None => Ok(val),
-            Some(e) => Err(e),
-        }
-    }
-}
-
-impl<I, T, E> Iterator for ResultShunt<I, E>
-    where I: Iterator<Item = Result<T, E>>
-{
-    type Item = T;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        match self.iter.next() {
-            Some(Ok(v)) => Some(v),
-            Some(Err(e)) => {
-                self.error = Some(e);
-                None
-            }
-            None => None,
-        }
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        if self.error.is_some() {
-            (0, Some(0))
-        } else {
-            let (_, upper) = self.iter.size_hint();
-            (0, upper)
-        }
-    }
-}
-
-#[stable(feature = "iter_arith_traits_result", since="1.16.0")]
-impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
-    where T: Sum<U>,
-{
-    /// Takes each element in the `Iterator`: if it is an `Err`, no further
-    /// elements are taken, and the `Err` is returned. Should no `Err` occur,
-    /// the sum of all elements is returned.
-    ///
-    /// # Examples
-    ///
-    /// This sums up every integer in a vector, rejecting the sum if a negative
-    /// element is encountered:
-    ///
-    /// ```
-    /// let v = vec![1, 2];
-    /// let res: Result<i32, &'static str> = v.iter().map(|&x: &i32|
-    ///     if x < 0 { Err("Negative element found") }
-    ///     else { Ok(x) }
-    /// ).sum();
-    /// assert_eq!(res, Ok(3));
-    /// ```
-    fn sum<I>(iter: I) -> Result<T, E>
-        where I: Iterator<Item = Result<U, E>>,
-    {
-        ResultShunt::process(iter, |i| i.sum())
-    }
-}
-
-#[stable(feature = "iter_arith_traits_result", since="1.16.0")]
-impl<T, U, E> Product<Result<U, E>> for Result<T, E>
-    where T: Product<U>,
-{
-    /// Takes each element in the `Iterator`: if it is an `Err`, no further
-    /// elements are taken, and the `Err` is returned. Should no `Err` occur,
-    /// the product of all elements is returned.
-    fn product<I>(iter: I) -> Result<T, E>
-        where I: Iterator<Item = Result<U, E>>,
-    {
-        ResultShunt::process(iter, |i| i.product())
-    }
-}
-
-/// An iterator that always continues to yield `None` when exhausted.
-///
-/// Calling next on a fused iterator that has returned `None` once is guaranteed
-/// to return [`None`] again. This trait should be implemented by all iterators
-/// that behave this way because it allows optimizing [`Iterator::fuse`].
-///
-/// Note: In general, you should not use `FusedIterator` in generic bounds if
-/// you need a fused iterator. Instead, you should just call [`Iterator::fuse`]
-/// on the iterator. If the iterator is already fused, the additional [`Fuse`]
-/// wrapper will be a no-op with no performance penalty.
-///
-/// [`None`]: ../../std/option/enum.Option.html#variant.None
-/// [`Iterator::fuse`]: ../../std/iter/trait.Iterator.html#method.fuse
-/// [`Fuse`]: ../../std/iter/struct.Fuse.html
-#[stable(feature = "fused", since = "1.26.0")]
-pub trait FusedIterator: Iterator {}
-
-#[stable(feature = "fused", since = "1.26.0")]
-impl<I: FusedIterator + ?Sized> FusedIterator for &mut I {}
-
-/// An iterator that reports an accurate length using size_hint.
-///
-/// The iterator reports a size hint where it is either exact
-/// (lower bound is equal to upper bound), or the upper bound is [`None`].
-/// The upper bound must only be [`None`] if the actual iterator length is
-/// larger than [`usize::MAX`]. In that case, the lower bound must be
-/// [`usize::MAX`], resulting in a [`.size_hint`] of `(usize::MAX, None)`.
-///
-/// The iterator must produce exactly the number of elements it reported
-/// or diverge before reaching the end.
-///
-/// # Safety
-///
-/// This trait must only be implemented when the contract is upheld.
-/// Consumers of this trait must inspect [`.size_hint`]’s upper bound.
-///
-/// [`None`]: ../../std/option/enum.Option.html#variant.None
-/// [`usize::MAX`]: ../../std/usize/constant.MAX.html
-/// [`.size_hint`]: ../../std/iter/trait.Iterator.html#method.size_hint
-#[unstable(feature = "trusted_len", issue = "37572")]
-pub unsafe trait TrustedLen : Iterator {}
-
-#[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<I: TrustedLen + ?Sized> TrustedLen for &mut I {}
diff --git a/src/libcore/iter/traits/accum.rs b/src/libcore/iter/traits/accum.rs
new file mode 100644
index 0000000000000..dfe1d2a1006d7
--- /dev/null
+++ b/src/libcore/iter/traits/accum.rs
@@ -0,0 +1,225 @@
+use ops::{Mul, Add};
+use num::Wrapping;
+
+/// Trait to represent types that can be created by summing up an iterator.
+///
+/// This trait is used to implement the [`sum`] method on iterators. Types which
+/// implement the trait can be generated by the [`sum`] method. Like
+/// [`FromIterator`] this trait should rarely be called directly and instead
+/// interacted with through [`Iterator::sum`].
+///
+/// [`sum`]: ../../std/iter/trait.Sum.html#tymethod.sum
+/// [`FromIterator`]: ../../std/iter/trait.FromIterator.html
+/// [`Iterator::sum`]: ../../std/iter/trait.Iterator.html#method.sum
+#[stable(feature = "iter_arith_traits", since = "1.12.0")]
+pub trait Sum<A = Self>: Sized {
+    /// Method which takes an iterator and generates `Self` from the elements by
+    /// "summing up" the items.
+    #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+    fn sum<I: Iterator<Item=A>>(iter: I) -> Self;
+}
+
+/// Trait to represent types that can be created by multiplying elements of an
+/// iterator.
+///
+/// This trait is used to implement the [`product`] method on iterators. Types
+/// which implement the trait can be generated by the [`product`] method. Like
+/// [`FromIterator`] this trait should rarely be called directly and instead
+/// interacted with through [`Iterator::product`].
+///
+/// [`product`]: ../../std/iter/trait.Product.html#tymethod.product
+/// [`FromIterator`]: ../../std/iter/trait.FromIterator.html
+/// [`Iterator::product`]: ../../std/iter/trait.Iterator.html#method.product
+#[stable(feature = "iter_arith_traits", since = "1.12.0")]
+pub trait Product<A = Self>: Sized {
+    /// Method which takes an iterator and generates `Self` from the elements by
+    /// multiplying the items.
+    #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+    fn product<I: Iterator<Item=A>>(iter: I) -> Self;
+}
+
+// N.B., explicitly use Add and Mul here to inherit overflow checks
+macro_rules! integer_sum_product {
+    (@impls $zero:expr, $one:expr, #[$attr:meta], $($a:ty)*) => ($(
+        #[$attr]
+        impl Sum for $a {
+            fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
+                iter.fold($zero, Add::add)
+            }
+        }
+
+        #[$attr]
+        impl Product for $a {
+            fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
+                iter.fold($one, Mul::mul)
+            }
+        }
+
+        #[$attr]
+        impl<'a> Sum<&'a $a> for $a {
+            fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
+                iter.fold($zero, Add::add)
+            }
+        }
+
+        #[$attr]
+        impl<'a> Product<&'a $a> for $a {
+            fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
+                iter.fold($one, Mul::mul)
+            }
+        }
+    )*);
+    ($($a:ty)*) => (
+        integer_sum_product!(@impls 0, 1,
+                #[stable(feature = "iter_arith_traits", since = "1.12.0")],
+                $($a)+);
+        integer_sum_product!(@impls Wrapping(0), Wrapping(1),
+                #[stable(feature = "wrapping_iter_arith", since = "1.14.0")],
+                $(Wrapping<$a>)+);
+    );
+}
+
+macro_rules! float_sum_product {
+    ($($a:ident)*) => ($(
+        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        impl Sum for $a {
+            fn sum<I: Iterator<Item=$a>>(iter: I) -> $a {
+                iter.fold(0.0, |a, b| a + b)
+            }
+        }
+
+        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        impl Product for $a {
+            fn product<I: Iterator<Item=$a>>(iter: I) -> $a {
+                iter.fold(1.0, |a, b| a * b)
+            }
+        }
+
+        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        impl<'a> Sum<&'a $a> for $a {
+            fn sum<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
+                iter.fold(0.0, |a, b| a + *b)
+            }
+        }
+
+        #[stable(feature = "iter_arith_traits", since = "1.12.0")]
+        impl<'a> Product<&'a $a> for $a {
+            fn product<I: Iterator<Item=&'a $a>>(iter: I) -> $a {
+                iter.fold(1.0, |a, b| a * *b)
+            }
+        }
+    )*)
+}
+
+integer_sum_product! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
+float_sum_product! { f32 f64 }
+
+/// An iterator adapter that produces output as long as the underlying
+/// iterator produces `Result::Ok` values.
+///
+/// If an error is encountered, the iterator stops and the error is
+/// stored. The error may be recovered later via `reconstruct`.
+struct ResultShunt<I, E> {
+    iter: I,
+    error: Option<E>,
+}
+
+impl<I, T, E> ResultShunt<I, E>
+    where I: Iterator<Item = Result<T, E>>
+{
+    /// Process the given iterator as if it yielded a `T` instead of a
+    /// `Result<T, _>`. Any errors will stop the inner iterator and
+    /// the overall result will be an error.
+    pub fn process<F, U>(iter: I, mut f: F) -> Result<U, E>
+        where F: FnMut(&mut Self) -> U
+    {
+        let mut shunt = ResultShunt::new(iter);
+        let value = f(shunt.by_ref());
+        shunt.reconstruct(value)
+    }
+
+    fn new(iter: I) -> Self {
+        ResultShunt {
+            iter,
+            error: None,
+        }
+    }
+
+    /// Consume the adapter and rebuild a `Result` value. This should
+    /// *always* be called, otherwise any potential error would be
+    /// lost.
+    fn reconstruct<U>(self, val: U) -> Result<U, E> {
+        match self.error {
+            None => Ok(val),
+            Some(e) => Err(e),
+        }
+    }
+}
+
+impl<I, T, E> Iterator for ResultShunt<I, E>
+    where I: Iterator<Item = Result<T, E>>
+{
+    type Item = T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.iter.next() {
+            Some(Ok(v)) => Some(v),
+            Some(Err(e)) => {
+                self.error = Some(e);
+                None
+            }
+            None => None,
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        if self.error.is_some() {
+            (0, Some(0))
+        } else {
+            let (_, upper) = self.iter.size_hint();
+            (0, upper)
+        }
+    }
+}
+
+#[stable(feature = "iter_arith_traits_result", since="1.16.0")]
+impl<T, U, E> Sum<Result<U, E>> for Result<T, E>
+    where T: Sum<U>,
+{
+    /// Takes each element in the `Iterator`: if it is an `Err`, no further
+    /// elements are taken, and the `Err` is returned. Should no `Err` occur,
+    /// the sum of all elements is returned.
+    ///
+    /// # Examples
+    ///
+    /// This sums up every integer in a vector, rejecting the sum if a negative
+    /// element is encountered:
+    ///
+    /// ```
+    /// let v = vec![1, 2];
+    /// let res: Result<i32, &'static str> = v.iter().map(|&x: &i32|
+    ///     if x < 0 { Err("Negative element found") }
+    ///     else { Ok(x) }
+    /// ).sum();
+    /// assert_eq!(res, Ok(3));
+    /// ```
+    fn sum<I>(iter: I) -> Result<T, E>
+        where I: Iterator<Item = Result<U, E>>,
+    {
+        ResultShunt::process(iter, |i| i.sum())
+    }
+}
+
+#[stable(feature = "iter_arith_traits_result", since="1.16.0")]
+impl<T, U, E> Product<Result<U, E>> for Result<T, E>
+    where T: Product<U>,
+{
+    /// Takes each element in the `Iterator`: if it is an `Err`, no further
+    /// elements are taken, and the `Err` is returned. Should no `Err` occur,
+    /// the product of all elements is returned.
+    fn product<I>(iter: I) -> Result<T, E>
+        where I: Iterator<Item = Result<U, E>>,
+    {
+        ResultShunt::process(iter, |i| i.product())
+    }
+}
diff --git a/src/libcore/iter/traits/collect.rs b/src/libcore/iter/traits/collect.rs
new file mode 100644
index 0000000000000..5204f6a642509
--- /dev/null
+++ b/src/libcore/iter/traits/collect.rs
@@ -0,0 +1,349 @@
+/// Conversion from an `Iterator`.
+///
+/// By implementing `FromIterator` for a type, you define how it will be
+/// created from an iterator. This is common for types which describe a
+/// collection of some kind.
+///
+/// `FromIterator`'s [`from_iter`] is rarely called explicitly, and is instead
+/// used through [`Iterator`]'s [`collect`] method. See [`collect`]'s
+/// documentation for more examples.
+///
+/// [`from_iter`]: #tymethod.from_iter
+/// [`Iterator`]: trait.Iterator.html
+/// [`collect`]: trait.Iterator.html#method.collect
+///
+/// See also: [`IntoIterator`].
+///
+/// [`IntoIterator`]: trait.IntoIterator.html
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// use std::iter::FromIterator;
+///
+/// let five_fives = std::iter::repeat(5).take(5);
+///
+/// let v = Vec::from_iter(five_fives);
+///
+/// assert_eq!(v, vec![5, 5, 5, 5, 5]);
+/// ```
+///
+/// Using [`collect`] to implicitly use `FromIterator`:
+///
+/// ```
+/// let five_fives = std::iter::repeat(5).take(5);
+///
+/// let v: Vec<i32> = five_fives.collect();
+///
+/// assert_eq!(v, vec![5, 5, 5, 5, 5]);
+/// ```
+///
+/// Implementing `FromIterator` for your type:
+///
+/// ```
+/// use std::iter::FromIterator;
+///
+/// // A sample collection, that's just a wrapper over Vec<T>
+/// #[derive(Debug)]
+/// struct MyCollection(Vec<i32>);
+///
+/// // Let's give it some methods so we can create one and add things
+/// // to it.
+/// impl MyCollection {
+///     fn new() -> MyCollection {
+///         MyCollection(Vec::new())
+///     }
+///
+///     fn add(&mut self, elem: i32) {
+///         self.0.push(elem);
+///     }
+/// }
+///
+/// // and we'll implement FromIterator
+/// impl FromIterator<i32> for MyCollection {
+///     fn from_iter<I: IntoIterator<Item=i32>>(iter: I) -> Self {
+///         let mut c = MyCollection::new();
+///
+///         for i in iter {
+///             c.add(i);
+///         }
+///
+///         c
+///     }
+/// }
+///
+/// // Now we can make a new iterator...
+/// let iter = (0..5).into_iter();
+///
+/// // ... and make a MyCollection out of it
+/// let c = MyCollection::from_iter(iter);
+///
+/// assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
+///
+/// // collect works too!
+///
+/// let iter = (0..5).into_iter();
+/// let c: MyCollection = iter.collect();
+///
+/// assert_eq!(c.0, vec![0, 1, 2, 3, 4]);
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented(
+    message="a collection of type `{Self}` cannot be built from an iterator \
+             over elements of type `{A}`",
+    label="a collection of type `{Self}` cannot be built from `std::iter::Iterator<Item={A}>`",
+)]
+pub trait FromIterator<A>: Sized {
+    /// Creates a value from an iterator.
+    ///
+    /// See the [module-level documentation] for more.
+    ///
+    /// [module-level documentation]: index.html
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// use std::iter::FromIterator;
+    ///
+    /// let five_fives = std::iter::repeat(5).take(5);
+    ///
+    /// let v = Vec::from_iter(five_fives);
+    ///
+    /// assert_eq!(v, vec![5, 5, 5, 5, 5]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn from_iter<T: IntoIterator<Item=A>>(iter: T) -> Self;
+}
+
+/// Conversion into an `Iterator`.
+///
+/// By implementing `IntoIterator` for a type, you define how it will be
+/// converted to an iterator. This is common for types which describe a
+/// collection of some kind.
+///
+/// One benefit of implementing `IntoIterator` is that your type will [work
+/// with Rust's `for` loop syntax](index.html#for-loops-and-intoiterator).
+///
+/// See also: [`FromIterator`].
+///
+/// [`FromIterator`]: trait.FromIterator.html
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// let v = vec![1, 2, 3];
+/// let mut iter = v.into_iter();
+///
+/// assert_eq!(Some(1), iter.next());
+/// assert_eq!(Some(2), iter.next());
+/// assert_eq!(Some(3), iter.next());
+/// assert_eq!(None, iter.next());
+/// ```
+/// Implementing `IntoIterator` for your type:
+///
+/// ```
+/// // A sample collection, that's just a wrapper over Vec<T>
+/// #[derive(Debug)]
+/// struct MyCollection(Vec<i32>);
+///
+/// // Let's give it some methods so we can create one and add things
+/// // to it.
+/// impl MyCollection {
+///     fn new() -> MyCollection {
+///         MyCollection(Vec::new())
+///     }
+///
+///     fn add(&mut self, elem: i32) {
+///         self.0.push(elem);
+///     }
+/// }
+///
+/// // and we'll implement IntoIterator
+/// impl IntoIterator for MyCollection {
+///     type Item = i32;
+///     type IntoIter = ::std::vec::IntoIter<i32>;
+///
+///     fn into_iter(self) -> Self::IntoIter {
+///         self.0.into_iter()
+///     }
+/// }
+///
+/// // Now we can make a new collection...
+/// let mut c = MyCollection::new();
+///
+/// // ... add some stuff to it ...
+/// c.add(0);
+/// c.add(1);
+/// c.add(2);
+///
+/// // ... and then turn it into an Iterator:
+/// for (i, n) in c.into_iter().enumerate() {
+///     assert_eq!(i as i32, n);
+/// }
+/// ```
+///
+/// It is common to use `IntoIterator` as a trait bound. This allows
+/// the input collection type to change, so long as it is still an
+/// iterator. Additional bounds can be specified by restricting on
+/// `Item`:
+///
+/// ```rust
+/// fn collect_as_strings<T>(collection: T) -> Vec<String>
+///     where T: IntoIterator,
+///           T::Item : std::fmt::Debug,
+/// {
+///     collection
+///         .into_iter()
+///         .map(|item| format!("{:?}", item))
+///         .collect()
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait IntoIterator {
+    /// The type of the elements being iterated over.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    type Item;
+
+    /// Which kind of iterator are we turning this into?
+    #[stable(feature = "rust1", since = "1.0.0")]
+    type IntoIter: Iterator<Item=Self::Item>;
+
+    /// Creates an iterator from a value.
+    ///
+    /// See the [module-level documentation] for more.
+    ///
+    /// [module-level documentation]: index.html
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let v = vec![1, 2, 3];
+    /// let mut iter = v.into_iter();
+    ///
+    /// assert_eq!(Some(1), iter.next());
+    /// assert_eq!(Some(2), iter.next());
+    /// assert_eq!(Some(3), iter.next());
+    /// assert_eq!(None, iter.next());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn into_iter(self) -> Self::IntoIter;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator> IntoIterator for I {
+    type Item = I::Item;
+    type IntoIter = I;
+
+    fn into_iter(self) -> I {
+        self
+    }
+}
+
+/// Extend a collection with the contents of an iterator.
+///
+/// Iterators produce a series of values, and collections can also be thought
+/// of as a series of values. The `Extend` trait bridges this gap, allowing you
+/// to extend a collection by including the contents of that iterator. When
+/// extending a collection with an already existing key, that entry is updated
+/// or, in the case of collections that permit multiple entries with equal
+/// keys, that entry is inserted.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // You can extend a String with some chars:
+/// let mut message = String::from("The first three letters are: ");
+///
+/// message.extend(&['a', 'b', 'c']);
+///
+/// assert_eq!("abc", &message[29..32]);
+/// ```
+///
+/// Implementing `Extend`:
+///
+/// ```
+/// // A sample collection, that's just a wrapper over Vec<T>
+/// #[derive(Debug)]
+/// struct MyCollection(Vec<i32>);
+///
+/// // Let's give it some methods so we can create one and add things
+/// // to it.
+/// impl MyCollection {
+///     fn new() -> MyCollection {
+///         MyCollection(Vec::new())
+///     }
+///
+///     fn add(&mut self, elem: i32) {
+///         self.0.push(elem);
+///     }
+/// }
+///
+/// // since MyCollection has a list of i32s, we implement Extend for i32
+/// impl Extend<i32> for MyCollection {
+///
+///     // This is a bit simpler with the concrete type signature: we can call
+///     // extend on anything which can be turned into an Iterator which gives
+///     // us i32s. Because we need i32s to put into MyCollection.
+///     fn extend<T: IntoIterator<Item=i32>>(&mut self, iter: T) {
+///
+///         // The implementation is very straightforward: loop through the
+///         // iterator, and add() each element to ourselves.
+///         for elem in iter {
+///             self.add(elem);
+///         }
+///     }
+/// }
+///
+/// let mut c = MyCollection::new();
+///
+/// c.add(5);
+/// c.add(6);
+/// c.add(7);
+///
+/// // let's extend our collection with three more numbers
+/// c.extend(vec![1, 2, 3]);
+///
+/// // we've added these elements onto the end
+/// assert_eq!("MyCollection([5, 6, 7, 1, 2, 3])", format!("{:?}", c));
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Extend<A> {
+    /// Extends a collection with the contents of an iterator.
+    ///
+    /// As this is the only method for this trait, the [trait-level] docs
+    /// contain more details.
+    ///
+    /// [trait-level]: trait.Extend.html
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // You can extend a String with some chars:
+    /// let mut message = String::from("abc");
+    ///
+    /// message.extend(['d', 'e', 'f'].iter());
+    ///
+    /// assert_eq!("abcdef", &message);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn extend<T: IntoIterator<Item=A>>(&mut self, iter: T);
+}
+
+#[stable(feature = "extend_for_unit", since = "1.28.0")]
+impl Extend<()> for () {
+    fn extend<T: IntoIterator<Item = ()>>(&mut self, iter: T) {
+        iter.into_iter().for_each(drop)
+    }
+}
diff --git a/src/libcore/iter/traits/double_ended.rs b/src/libcore/iter/traits/double_ended.rs
new file mode 100644
index 0000000000000..2976afc0b4f81
--- /dev/null
+++ b/src/libcore/iter/traits/double_ended.rs
@@ -0,0 +1,297 @@
+use ops::Try;
+use iter::LoopState;
+
+/// An iterator able to yield elements from both ends.
+///
+/// Something that implements `DoubleEndedIterator` has one extra capability
+/// over something that implements [`Iterator`]: the ability to also take
+/// `Item`s from the back, as well as the front.
+///
+/// It is important to note that both back and forth work on the same range,
+/// and do not cross: iteration is over when they meet in the middle.
+///
+/// In a similar fashion to the [`Iterator`] protocol, once a
+/// `DoubleEndedIterator` returns `None` from a `next_back()`, calling it again
+/// may or may not ever return `Some` again. `next()` and `next_back()` are
+/// interchangeable for this purpose.
+///
+/// [`Iterator`]: trait.Iterator.html
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// let numbers = vec![1, 2, 3, 4, 5, 6];
+///
+/// let mut iter = numbers.iter();
+///
+/// assert_eq!(Some(&1), iter.next());
+/// assert_eq!(Some(&6), iter.next_back());
+/// assert_eq!(Some(&5), iter.next_back());
+/// assert_eq!(Some(&2), iter.next());
+/// assert_eq!(Some(&3), iter.next());
+/// assert_eq!(Some(&4), iter.next());
+/// assert_eq!(None, iter.next());
+/// assert_eq!(None, iter.next_back());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait DoubleEndedIterator: Iterator {
+    /// Removes and returns an element from the end of the iterator.
+    ///
+    /// Returns `None` when there are no more elements.
+    ///
+    /// The [trait-level] docs contain more details.
+    ///
+    /// [trait-level]: trait.DoubleEndedIterator.html
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let numbers = vec![1, 2, 3, 4, 5, 6];
+    ///
+    /// let mut iter = numbers.iter();
+    ///
+    /// assert_eq!(Some(&1), iter.next());
+    /// assert_eq!(Some(&6), iter.next_back());
+    /// assert_eq!(Some(&5), iter.next_back());
+    /// assert_eq!(Some(&2), iter.next());
+    /// assert_eq!(Some(&3), iter.next());
+    /// assert_eq!(Some(&4), iter.next());
+    /// assert_eq!(None, iter.next());
+    /// assert_eq!(None, iter.next_back());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn next_back(&mut self) -> Option<Self::Item>;
+
+    /// Returns the `n`th element from the end of the iterator.
+    ///
+    /// This is essentially the reversed version of [`nth`]. Although like most indexing
+    /// operations, the count starts from zero, so `nth_back(0)` returns the first value fro
+    /// the end, `nth_back(1)` the second, and so on.
+    ///
+    /// Note that all elements between the end and the returned element will be
+    /// consumed, including the returned element. This also means that calling
+    /// `nth_back(0)` multiple times on the same iterator will return different
+    /// elements.
+    ///
+    /// `nth_back()` will return [`None`] if `n` is greater than or equal to the length of the
+    /// iterator.
+    ///
+    /// [`None`]: ../../std/option/enum.Option.html#variant.None
+    /// [`nth`]: ../../std/iter/trait.Iterator.html#method.nth
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// #![feature(iter_nth_back)]
+    /// let a = [1, 2, 3];
+    /// assert_eq!(a.iter().nth_back(2), Some(&1));
+    /// ```
+    ///
+    /// Calling `nth_back()` multiple times doesn't rewind the iterator:
+    ///
+    /// ```
+    /// #![feature(iter_nth_back)]
+    /// let a = [1, 2, 3];
+    ///
+    /// let mut iter = a.iter();
+    ///
+    /// assert_eq!(iter.nth_back(1), Some(&2));
+    /// assert_eq!(iter.nth_back(1), None);
+    /// ```
+    ///
+    /// Returning `None` if there are less than `n + 1` elements:
+    ///
+    /// ```
+    /// #![feature(iter_nth_back)]
+    /// let a = [1, 2, 3];
+    /// assert_eq!(a.iter().nth_back(10), None);
+    /// ```
+    #[inline]
+    #[unstable(feature = "iter_nth_back", issue = "56995")]
+    fn nth_back(&mut self, mut n: usize) -> Option<Self::Item> {
+        for x in self.rev() {
+            if n == 0 { return Some(x) }
+            n -= 1;
+        }
+        None
+    }
+
+    /// This is the reverse version of [`try_fold()`]: it takes elements
+    /// starting from the back of the iterator.
+    ///
+    /// [`try_fold()`]: trait.Iterator.html#method.try_fold
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let a = ["1", "2", "3"];
+    /// let sum = a.iter()
+    ///     .map(|&s| s.parse::<i32>())
+    ///     .try_rfold(0, |acc, x| x.and_then(|y| Ok(acc + y)));
+    /// assert_eq!(sum, Ok(6));
+    /// ```
+    ///
+    /// Short-circuiting:
+    ///
+    /// ```
+    /// let a = ["1", "rust", "3"];
+    /// let mut it = a.iter();
+    /// let sum = it
+    ///     .by_ref()
+    ///     .map(|&s| s.parse::<i32>())
+    ///     .try_rfold(0, |acc, x| x.and_then(|y| Ok(acc + y)));
+    /// assert!(sum.is_err());
+    ///
+    /// // Because it short-circuited, the remaining elements are still
+    /// // available through the iterator.
+    /// assert_eq!(it.next_back(), Some(&"1"));
+    /// ```
+    #[inline]
+    #[stable(feature = "iterator_try_fold", since = "1.27.0")]
+    fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> R,
+        R: Try<Ok=B>
+    {
+        let mut accum = init;
+        while let Some(x) = self.next_back() {
+            accum = f(accum, x)?;
+        }
+        Try::from_ok(accum)
+    }
+
+    /// An iterator method that reduces the iterator's elements to a single,
+    /// final value, starting from the back.
+    ///
+    /// This is the reverse version of [`fold()`]: it takes elements starting from
+    /// the back of the iterator.
+    ///
+    /// `rfold()` takes two arguments: an initial value, and a closure with two
+    /// arguments: an 'accumulator', and an element. The closure returns the value that
+    /// the accumulator should have for the next iteration.
+    ///
+    /// The initial value is the value the accumulator will have on the first
+    /// call.
+    ///
+    /// After applying this closure to every element of the iterator, `rfold()`
+    /// returns the accumulator.
+    ///
+    /// This operation is sometimes called 'reduce' or 'inject'.
+    ///
+    /// Folding is useful whenever you have a collection of something, and want
+    /// to produce a single value from it.
+    ///
+    /// [`fold()`]: trait.Iterator.html#method.fold
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let a = [1, 2, 3];
+    ///
+    /// // the sum of all of the elements of a
+    /// let sum = a.iter()
+    ///            .rfold(0, |acc, &x| acc + x);
+    ///
+    /// assert_eq!(sum, 6);
+    /// ```
+    ///
+    /// This example builds a string, starting with an initial value
+    /// and continuing with each element from the back until the front:
+    ///
+    /// ```
+    /// let numbers = [1, 2, 3, 4, 5];
+    ///
+    /// let zero = "0".to_string();
+    ///
+    /// let result = numbers.iter().rfold(zero, |acc, &x| {
+    ///     format!("({} + {})", x, acc)
+    /// });
+    ///
+    /// assert_eq!(result, "(1 + (2 + (3 + (4 + (5 + 0)))))");
+    /// ```
+    #[inline]
+    #[stable(feature = "iter_rfold", since = "1.27.0")]
+    fn rfold<B, F>(mut self, accum: B, mut f: F) -> B
+    where
+        Self: Sized,
+        F: FnMut(B, Self::Item) -> B,
+    {
+        self.try_rfold(accum, move |acc, x| Ok::<B, !>(f(acc, x))).unwrap()
+    }
+
+    /// Searches for an element of an iterator from the back that satisfies a predicate.
+    ///
+    /// `rfind()` takes a closure that returns `true` or `false`. It applies
+    /// this closure to each element of the iterator, starting at the end, and if any
+    /// of them return `true`, then `rfind()` returns [`Some(element)`]. If they all return
+    /// `false`, it returns [`None`].
+    ///
+    /// `rfind()` is short-circuiting; in other words, it will stop processing
+    /// as soon as the closure returns `true`.
+    ///
+    /// Because `rfind()` takes a reference, and many iterators iterate over
+    /// references, this leads to a possibly confusing situation where the
+    /// argument is a double reference. You can see this effect in the
+    /// examples below, with `&&x`.
+    ///
+    /// [`Some(element)`]: ../../std/option/enum.Option.html#variant.Some
+    /// [`None`]: ../../std/option/enum.Option.html#variant.None
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let a = [1, 2, 3];
+    ///
+    /// assert_eq!(a.iter().rfind(|&&x| x == 2), Some(&2));
+    ///
+    /// assert_eq!(a.iter().rfind(|&&x| x == 5), None);
+    /// ```
+    ///
+    /// Stopping at the first `true`:
+    ///
+    /// ```
+    /// let a = [1, 2, 3];
+    ///
+    /// let mut iter = a.iter();
+    ///
+    /// assert_eq!(iter.rfind(|&&x| x == 2), Some(&2));
+    ///
+    /// // we can still use `iter`, as there are more elements.
+    /// assert_eq!(iter.next_back(), Some(&1));
+    /// ```
+    #[inline]
+    #[stable(feature = "iter_rfind", since = "1.27.0")]
+    fn rfind<P>(&mut self, mut predicate: P) -> Option<Self::Item>
+    where
+        Self: Sized,
+        P: FnMut(&Self::Item) -> bool
+    {
+        self.try_rfold((), move |(), x| {
+            if predicate(&x) { LoopState::Break(x) }
+            else { LoopState::Continue(()) }
+        }).break_value()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, I: DoubleEndedIterator + ?Sized> DoubleEndedIterator for &'a mut I {
+    fn next_back(&mut self) -> Option<I::Item> {
+        (**self).next_back()
+    }
+    fn nth_back(&mut self, n: usize) -> Option<I::Item> {
+        (**self).nth_back(n)
+    }
+}
diff --git a/src/libcore/iter/traits/exact_size.rs b/src/libcore/iter/traits/exact_size.rs
new file mode 100644
index 0000000000000..d6eab40213edb
--- /dev/null
+++ b/src/libcore/iter/traits/exact_size.rs
@@ -0,0 +1,143 @@
+/// An iterator that knows its exact length.
+///
+/// Many [`Iterator`]s don't know how many times they will iterate, but some do.
+/// If an iterator knows how many times it can iterate, providing access to
+/// that information can be useful. For example, if you want to iterate
+/// backwards, a good start is to know where the end is.
+///
+/// When implementing an `ExactSizeIterator`, you must also implement
+/// [`Iterator`]. When doing so, the implementation of [`size_hint`] *must*
+/// return the exact size of the iterator.
+///
+/// [`Iterator`]: trait.Iterator.html
+/// [`size_hint`]: trait.Iterator.html#method.size_hint
+///
+/// The [`len`] method has a default implementation, so you usually shouldn't
+/// implement it. However, you may be able to provide a more performant
+/// implementation than the default, so overriding it in this case makes sense.
+///
+/// [`len`]: #method.len
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // a finite range knows exactly how many times it will iterate
+/// let five = 0..5;
+///
+/// assert_eq!(5, five.len());
+/// ```
+///
+/// In the [module level docs][moddocs], we implemented an [`Iterator`],
+/// `Counter`. Let's implement `ExactSizeIterator` for it as well:
+///
+/// [moddocs]: index.html
+///
+/// ```
+/// # struct Counter {
+/// #     count: usize,
+/// # }
+/// # impl Counter {
+/// #     fn new() -> Counter {
+/// #         Counter { count: 0 }
+/// #     }
+/// # }
+/// # impl Iterator for Counter {
+/// #     type Item = usize;
+/// #     fn next(&mut self) -> Option<usize> {
+/// #         self.count += 1;
+/// #         if self.count < 6 {
+/// #             Some(self.count)
+/// #         } else {
+/// #             None
+/// #         }
+/// #     }
+/// # }
+/// impl ExactSizeIterator for Counter {
+///     // We can easily calculate the remaining number of iterations.
+///     fn len(&self) -> usize {
+///         5 - self.count
+///     }
+/// }
+///
+/// // And now we can use it!
+///
+/// let counter = Counter::new();
+///
+/// assert_eq!(5, counter.len());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ExactSizeIterator: Iterator {
+    /// Returns the exact number of times the iterator will iterate.
+    ///
+    /// This method has a default implementation, so you usually should not
+    /// implement it directly. However, if you can provide a more efficient
+    /// implementation, you can do so. See the [trait-level] docs for an
+    /// example.
+    ///
+    /// This function has the same safety guarantees as the [`size_hint`]
+    /// function.
+    ///
+    /// [trait-level]: trait.ExactSizeIterator.html
+    /// [`size_hint`]: trait.Iterator.html#method.size_hint
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // a finite range knows exactly how many times it will iterate
+    /// let five = 0..5;
+    ///
+    /// assert_eq!(5, five.len());
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn len(&self) -> usize {
+        let (lower, upper) = self.size_hint();
+        // Note: This assertion is overly defensive, but it checks the invariant
+        // guaranteed by the trait. If this trait were rust-internal,
+        // we could use debug_assert!; assert_eq! will check all Rust user
+        // implementations too.
+        assert_eq!(upper, Some(lower));
+        lower
+    }
+
+    /// Returns `true` if the iterator is empty.
+    ///
+    /// This method has a default implementation using `self.len()`, so you
+    /// don't need to implement it yourself.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// #![feature(exact_size_is_empty)]
+    ///
+    /// let mut one_element = std::iter::once(0);
+    /// assert!(!one_element.is_empty());
+    ///
+    /// assert_eq!(one_element.next(), Some(0));
+    /// assert!(one_element.is_empty());
+    ///
+    /// assert_eq!(one_element.next(), None);
+    /// ```
+    #[inline]
+    #[unstable(feature = "exact_size_is_empty", issue = "35428")]
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: ExactSizeIterator + ?Sized> ExactSizeIterator for &mut I {
+    fn len(&self) -> usize {
+        (**self).len()
+    }
+    fn is_empty(&self) -> bool {
+        (**self).is_empty()
+    }
+}
+
diff --git a/src/libcore/iter/iterator.rs b/src/libcore/iter/traits/iterator.rs
similarity index 95%
rename from src/libcore/iter/iterator.rs
rename to src/libcore/iter/traits/iterator.rs
index 0ad29afbadeac..861e9c3157a79 100644
--- a/src/libcore/iter/iterator.rs
+++ b/src/libcore/iter/traits/iterator.rs
@@ -1,12 +1,11 @@
 use cmp::Ordering;
 use ops::Try;
 
-use super::LoopState;
-use super::{Chain, Cycle, Copied, Cloned, Enumerate, Filter, FilterMap, Fuse};
-use super::{Flatten, FlatMap, flatten_compat};
-use super::{Inspect, Map, Peekable, Scan, Skip, SkipWhile, StepBy, Take, TakeWhile, Rev};
-use super::{Zip, Sum, Product};
-use super::{ChainState, FromIterator, ZipImpl};
+use super::super::LoopState;
+use super::super::{Chain, Cycle, Copied, Cloned, Enumerate, Filter, FilterMap, Fuse};
+use super::super::{Flatten, FlatMap};
+use super::super::{Inspect, Map, Peekable, Scan, Skip, SkipWhile, StepBy, Take, TakeWhile, Rev};
+use super::super::{Zip, Sum, Product, FromIterator};
 
 fn _assert_is_object_safe(_: &dyn Iterator<Item=()>) {}
 
@@ -121,7 +120,7 @@ pub trait Iterator {
     /// // ... and then None once it's over.
     /// assert_eq!(None, iter.next());
     ///
-    /// // More calls may or may not return None. Here, they always will.
+    /// // More calls may or may not return `None`. Here, they always will.
     /// assert_eq!(None, iter.next());
     /// assert_eq!(None, iter.next());
     /// ```
@@ -367,8 +366,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "iterator_step_by", since = "1.28.0")]
     fn step_by(self, step: usize) -> StepBy<Self> where Self: Sized {
-        assert!(step != 0);
-        StepBy{iter: self, step: step - 1, first_take: true}
+        StepBy::new(self, step)
     }
 
     /// Takes two iterators and creates a new iterator over both in sequence.
@@ -425,7 +423,7 @@ pub trait Iterator {
     fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where
         Self: Sized, U: IntoIterator<Item=Self::Item>,
     {
-        Chain{a: self, b: other.into_iter(), state: ChainState::Both}
+        Chain::new(self, other.into_iter())
     }
 
     /// 'Zips up' two iterators into a single iterator of pairs.
@@ -560,15 +558,15 @@ pub trait Iterator {
     fn map<B, F>(self, f: F) -> Map<Self, F> where
         Self: Sized, F: FnMut(Self::Item) -> B,
     {
-        Map { iter: self, f }
+        Map::new(self, f)
     }
 
     /// Calls a closure on each element of an iterator.
     ///
     /// This is equivalent to using a [`for`] loop on the iterator, although
-    /// `break` and `continue` are not possible from a closure.  It's generally
+    /// `break` and `continue` are not possible from a closure. It's generally
     /// more idiomatic to use a `for` loop, but `for_each` may be more legible
-    /// when processing items at the end of longer iterator chains.  In some
+    /// when processing items at the end of longer iterator chains. In some
     /// cases `for_each` may also be faster than a loop, because it will use
     /// internal iteration on adaptors like `Chain`.
     ///
@@ -671,7 +669,7 @@ pub trait Iterator {
     fn filter<P>(self, predicate: P) -> Filter<Self, P> where
         Self: Sized, P: FnMut(&Self::Item) -> bool,
     {
-        Filter {iter: self, predicate }
+        Filter::new(self, predicate)
     }
 
     /// Creates an iterator that both filters and maps.
@@ -728,7 +726,7 @@ pub trait Iterator {
     fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
         Self: Sized, F: FnMut(Self::Item) -> Option<B>,
     {
-        FilterMap { iter: self, f }
+        FilterMap::new(self, f)
     }
 
     /// Creates an iterator which gives the current iteration count as well as
@@ -772,7 +770,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn enumerate(self) -> Enumerate<Self> where Self: Sized {
-        Enumerate { iter: self, count: 0 }
+        Enumerate::new(self)
     }
 
     /// Creates an iterator which can use `peek` to look at the next element of
@@ -818,7 +816,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn peekable(self) -> Peekable<Self> where Self: Sized {
-        Peekable{iter: self, peeked: None}
+        Peekable::new(self)
     }
 
     /// Creates an iterator that [`skip`]s elements based on a predicate.
@@ -881,7 +879,7 @@ pub trait Iterator {
     fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
         Self: Sized, P: FnMut(&Self::Item) -> bool,
     {
-        SkipWhile { iter: self, flag: false, predicate }
+        SkipWhile::new(self, predicate)
     }
 
     /// Creates an iterator that yields elements based on a predicate.
@@ -954,14 +952,13 @@ pub trait Iterator {
     /// ```
     ///
     /// The `3` is no longer there, because it was consumed in order to see if
-    /// the iteration should stop, but wasn't placed back into the iterator or
-    /// some similar thing.
+    /// the iteration should stop, but wasn't placed back into the iterator.
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
         Self: Sized, P: FnMut(&Self::Item) -> bool,
     {
-        TakeWhile { iter: self, flag: false, predicate }
+        TakeWhile::new(self, predicate)
     }
 
     /// Creates an iterator that skips the first `n` elements.
@@ -983,7 +980,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn skip(self, n: usize) -> Skip<Self> where Self: Sized {
-        Skip { iter: self, n }
+        Skip::new(self, n)
     }
 
     /// Creates an iterator that yields its first `n` elements.
@@ -1015,7 +1012,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn take(self, n: usize) -> Take<Self> where Self: Sized, {
-        Take { iter: self, n }
+        Take::new(self, n)
     }
 
     /// An iterator adaptor similar to [`fold`] that holds internal state and
@@ -1060,7 +1057,7 @@ pub trait Iterator {
     fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>
         where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>,
     {
-        Scan { iter: self, f, state: initial_state }
+        Scan::new(self, initial_state, f)
     }
 
     /// Creates an iterator that works like map, but flattens nested structure.
@@ -1098,7 +1095,7 @@ pub trait Iterator {
     fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>
         where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U,
     {
-        FlatMap { inner: flatten_compat(self.map(f)) }
+        FlatMap::new(self, f)
     }
 
     /// Creates an iterator that flattens nested structure.
@@ -1166,7 +1163,7 @@ pub trait Iterator {
     #[stable(feature = "iterator_flatten", since = "1.29.0")]
     fn flatten(self) -> Flatten<Self>
     where Self: Sized, Self::Item: IntoIterator {
-        Flatten { inner: flatten_compat(self) }
+        Flatten::new(self)
     }
 
     /// Creates an iterator which ends after the first [`None`].
@@ -1218,7 +1215,7 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(4));
     /// assert_eq!(iter.next(), None);
     ///
-    /// // it will always return None after the first time.
+    /// // it will always return `None` after the first time.
     /// assert_eq!(iter.next(), None);
     /// assert_eq!(iter.next(), None);
     /// assert_eq!(iter.next(), None);
@@ -1226,7 +1223,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn fuse(self) -> Fuse<Self> where Self: Sized {
-        Fuse{iter: self, done: false}
+        Fuse::new(self)
     }
 
     /// Do something with each element of an iterator, passing the value on.
@@ -1309,7 +1306,7 @@ pub trait Iterator {
     fn inspect<F>(self, f: F) -> Inspect<Self, F> where
         Self: Sized, F: FnMut(&Self::Item),
     {
-        Inspect { iter: self, f }
+        Inspect::new(self, f)
     }
 
     /// Borrows an iterator, rather than consuming it.
@@ -1518,7 +1515,7 @@ pub trait Iterator {
     /// is propagated back to the caller immediately (short-circuiting).
     ///
     /// The initial value is the value the accumulator will have on the first
-    /// call.  If applying the closure succeeded against every element of the
+    /// call. If applying the closure succeeded against every element of the
     /// iterator, `try_fold()` returns the final accumulator as success.
     ///
     /// Folding is useful whenever you have a collection of something, and want
@@ -1531,10 +1528,10 @@ pub trait Iterator {
     /// do something better than the default `for` loop implementation.
     ///
     /// In particular, try to have this call `try_fold()` on the internal parts
-    /// from which this iterator is composed.  If multiple calls are needed,
+    /// from which this iterator is composed. If multiple calls are needed,
     /// the `?` operator may be convenient for chaining the accumulator value
     /// along, but beware any invariants that need to be upheld before those
-    /// early returns.  This is a `&mut self` method, so iteration needs to be
+    /// early returns. This is a `&mut self` method, so iteration needs to be
     /// resumable after hitting an error here.
     ///
     /// # Examples
@@ -2183,7 +2180,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn rev(self) -> Rev<Self> where Self: Sized + DoubleEndedIterator {
-        Rev{iter: self}
+        Rev::new(self)
     }
 
     /// Converts an iterator of pairs into a pair of containers.
@@ -2251,7 +2248,7 @@ pub trait Iterator {
     fn copied<'a, T: 'a>(self) -> Copied<Self>
         where Self: Sized + Iterator<Item=&'a T>, T: Copy
     {
-        Copied { it: self }
+        Copied::new(self)
     }
 
     /// Creates an iterator which [`clone`]s all of its elements.
@@ -2280,7 +2277,7 @@ pub trait Iterator {
     fn cloned<'a, T: 'a>(self) -> Cloned<Self>
         where Self: Sized + Iterator<Item=&'a T>, T: Clone
     {
-        Cloned { it: self }
+        Cloned::new(self)
     }
 
     /// Repeats an iterator endlessly.
@@ -2311,7 +2308,7 @@ pub trait Iterator {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     fn cycle(self) -> Cycle<Self> where Self: Sized + Clone {
-        Cycle{orig: self.clone(), iter: self}
+        Cycle::new(self)
     }
 
     /// Sums the elements of an iterator.
@@ -2605,6 +2602,95 @@ pub trait Iterator {
             }
         }
     }
+
+    /// Checks if the elements of this iterator are sorted.
+    ///
+    /// That is, for each element `a` and its following element `b`, `a <= b` must hold. If the
+    /// iterator yields exactly zero or one element, `true` is returned.
+    ///
+    /// Note that if `Self::Item` is only `PartialOrd`, but not `Ord`, the above definition
+    /// implies that this function returns `false` if any two consecutive items are not
+    /// comparable.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_sorted)]
+    ///
+    /// assert!([1, 2, 2, 9].iter().is_sorted());
+    /// assert!(![1, 3, 2, 4].iter().is_sorted());
+    /// assert!([0].iter().is_sorted());
+    /// assert!(std::iter::empty::<i32>().is_sorted());
+    /// assert!(![0.0, 1.0, std::f32::NAN].iter().is_sorted());
+    /// ```
+    #[inline]
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    fn is_sorted(self) -> bool
+    where
+        Self: Sized,
+        Self::Item: PartialOrd,
+    {
+        self.is_sorted_by(|a, b| a.partial_cmp(b))
+    }
+
+    /// Checks if the elements of this iterator are sorted using the given comparator function.
+    ///
+    /// Instead of using `PartialOrd::partial_cmp`, this function uses the given `compare`
+    /// function to determine the ordering of two elements. Apart from that, it's equivalent to
+    /// [`is_sorted`]; see its documentation for more information.
+    ///
+    /// [`is_sorted`]: trait.Iterator.html#method.is_sorted
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    fn is_sorted_by<F>(mut self, mut compare: F) -> bool
+    where
+        Self: Sized,
+        F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>
+    {
+        let mut last = match self.next() {
+            Some(e) => e,
+            None => return true,
+        };
+
+        while let Some(curr) = self.next() {
+            if compare(&last, &curr)
+                .map(|o| o == Ordering::Greater)
+                .unwrap_or(true)
+            {
+                return false;
+            }
+            last = curr;
+        }
+
+        true
+    }
+
+    /// Checks if the elements of this iterator are sorted using the given key extraction
+    /// function.
+    ///
+    /// Instead of comparing the iterator's elements directly, this function compares the keys of
+    /// the elements, as determined by `f`. Apart from that, it's equivalent to [`is_sorted`]; see
+    /// its documentation for more information.
+    ///
+    /// [`is_sorted`]: trait.Iterator.html#method.is_sorted
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_sorted)]
+    ///
+    /// assert!(["c", "bb", "aaa"].iter().is_sorted_by_key(|s| s.len()));
+    /// assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
+    /// ```
+    #[inline]
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    fn is_sorted_by_key<F, K>(self, mut f: F) -> bool
+    where
+        Self: Sized,
+        F: FnMut(&Self::Item) -> K,
+        K: PartialOrd
+    {
+        self.is_sorted_by(|a, b| f(a).partial_cmp(&f(b)))
+    }
 }
 
 /// Select an element from an iterator based on the given "projection"
diff --git a/src/libcore/iter/traits/marker.rs b/src/libcore/iter/traits/marker.rs
new file mode 100644
index 0000000000000..602619bce5a96
--- /dev/null
+++ b/src/libcore/iter/traits/marker.rs
@@ -0,0 +1,44 @@
+/// An iterator that always continues to yield `None` when exhausted.
+///
+/// Calling next on a fused iterator that has returned `None` once is guaranteed
+/// to return [`None`] again. This trait should be implemented by all iterators
+/// that behave this way because it allows optimizing [`Iterator::fuse`].
+///
+/// Note: In general, you should not use `FusedIterator` in generic bounds if
+/// you need a fused iterator. Instead, you should just call [`Iterator::fuse`]
+/// on the iterator. If the iterator is already fused, the additional [`Fuse`]
+/// wrapper will be a no-op with no performance penalty.
+///
+/// [`None`]: ../../std/option/enum.Option.html#variant.None
+/// [`Iterator::fuse`]: ../../std/iter/trait.Iterator.html#method.fuse
+/// [`Fuse`]: ../../std/iter/struct.Fuse.html
+#[stable(feature = "fused", since = "1.26.0")]
+pub trait FusedIterator: Iterator {}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator + ?Sized> FusedIterator for &mut I {}
+
+/// An iterator that reports an accurate length using size_hint.
+///
+/// The iterator reports a size hint where it is either exact
+/// (lower bound is equal to upper bound), or the upper bound is [`None`].
+/// The upper bound must only be [`None`] if the actual iterator length is
+/// larger than [`usize::MAX`]. In that case, the lower bound must be
+/// [`usize::MAX`], resulting in a [`.size_hint`] of `(usize::MAX, None)`.
+///
+/// The iterator must produce exactly the number of elements it reported
+/// or diverge before reaching the end.
+///
+/// # Safety
+///
+/// This trait must only be implemented when the contract is upheld.
+/// Consumers of this trait must inspect [`.size_hint`]’s upper bound.
+///
+/// [`None`]: ../../std/option/enum.Option.html#variant.None
+/// [`usize::MAX`]: ../../std/usize/constant.MAX.html
+/// [`.size_hint`]: ../../std/iter/trait.Iterator.html#method.size_hint
+#[unstable(feature = "trusted_len", issue = "37572")]
+pub unsafe trait TrustedLen : Iterator {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<I: TrustedLen + ?Sized> TrustedLen for &mut I {}
diff --git a/src/libcore/iter/traits/mod.rs b/src/libcore/iter/traits/mod.rs
new file mode 100644
index 0000000000000..cf3013f423c94
--- /dev/null
+++ b/src/libcore/iter/traits/mod.rs
@@ -0,0 +1,15 @@
+mod iterator;
+mod double_ended;
+mod exact_size;
+mod collect;
+mod accum;
+mod marker;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::iterator::Iterator;
+pub use self::double_ended::DoubleEndedIterator;
+pub use self::exact_size::ExactSizeIterator;
+pub use self::collect::{FromIterator, IntoIterator, Extend};
+pub use self::accum::{Sum, Product};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::marker::{FusedIterator, TrustedLen};
diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 33c0da8a54049..f2165c676fd44 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -24,7 +24,7 @@
 //!   often generated by LLVM. Additionally, this library can make explicit
 //!   calls to these functions. Their signatures are the same as found in C.
 //!   These functions are often provided by the system libc, but can also be
-//!   provided by the [rlibc crate](https://crates.io/crates/rlibc).
+//!   provided by the [compiler-builtins crate](https://crates.io/crates/compiler_builtins).
 //!
 //! * `rust_begin_panic` - This function takes four arguments, a
 //!   `fmt::Arguments`, a `&'static str`, and two `u32`'s. These four arguments
@@ -51,18 +51,17 @@
 #![cfg(not(test))]
 
 #![stable(feature = "core", since = "1.6.0")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject, attr(deny(warnings))),
        test(attr(allow(dead_code, deprecated, unused_variables, unused_mut))))]
-
 #![no_core]
-#![deny(missing_docs)]
-#![deny(intra_doc_link_resolution_failure)]
-#![deny(missing_debug_implementations)]
+
+#![warn(deprecated_in_future)]
+#![warn(missing_docs)]
+#![warn(intra_doc_link_resolution_failure)]
+#![warn(missing_debug_implementations)]
 
 #![feature(allow_internal_unstable)]
 #![feature(arbitrary_self_types)]
@@ -71,7 +70,6 @@
 #![feature(cfg_target_has_atomic)]
 #![feature(concat_idents)]
 #![feature(const_fn)]
-#![cfg_attr(stage0, feature(const_int_ops))]
 #![feature(const_fn_union)]
 #![feature(custom_attribute)]
 #![feature(doc_cfg)]
@@ -79,6 +77,7 @@
 #![feature(extern_types)]
 #![feature(fundamental)]
 #![feature(intrinsics)]
+#![feature(is_sorted)]
 #![feature(iter_once_with)]
 #![feature(lang_items)]
 #![feature(link_llvm_intrinsics)]
@@ -96,6 +95,7 @@
 #![feature(simd_ffi)]
 #![feature(specialization)]
 #![feature(staged_api)]
+#![feature(std_internals)]
 #![feature(stmt_expr_attributes)]
 #![feature(unboxed_closures)]
 #![feature(unsized_locals)]
@@ -111,19 +111,20 @@
 #![feature(aarch64_target_feature)]
 #![feature(wasm_target_feature)]
 #![feature(avx512_target_feature)]
-#![cfg_attr(not(stage0), feature(cmpxchg16b_target_feature))]
+#![feature(cmpxchg16b_target_feature)]
 #![feature(const_slice_len)]
 #![feature(const_str_as_bytes)]
 #![feature(const_str_len)]
-#![cfg_attr(stage0, feature(const_let))]
-#![cfg_attr(stage0, feature(const_int_rotate))]
 #![feature(const_int_conversion)]
 #![feature(const_transmute)]
 #![feature(reverse_bits)]
 #![feature(non_exhaustive)]
 #![feature(structural_match)]
 #![feature(abi_unadjusted)]
-#![cfg_attr(not(stage0), feature(adx_target_feature))]
+#![feature(adx_target_feature)]
+#![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)]
+#![feature(unrestricted_attribute_tokens)]
+#![feature(external_doc)]
 
 #[prelude_import]
 #[allow(unused)]
@@ -218,33 +219,19 @@ pub mod task;
 pub mod alloc;
 
 // note: does not need to be public
-mod iter_private;
 mod tuple;
 mod unit;
 
-// Pull in the `coresimd` crate directly into libcore. This is where all the
-// architecture-specific (and vendor-specific) intrinsics are defined. AKA
-// things like SIMD and such. Note that the actual source for all this lies in a
-// different repository, rust-lang-nursery/stdsimd. That's why the setup here is
-// a bit wonky.
-#[allow(unused_macros)]
-macro_rules! test_v16 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! test_v32 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! test_v64 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! test_v128 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! test_v256 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! test_v512 { ($item:item) => {}; }
-#[allow(unused_macros)]
-macro_rules! vector_impl { ($([$f:ident, $($args:tt)*]),*) => { $($f!($($args)*);)* } }
-#[path = "../stdsimd/coresimd/mod.rs"]
+// Pull in the `core_arch` crate directly into libcore. The contents of
+// `core_arch` are in a different repository: rust-lang-nursery/stdsimd.
+//
+// `core_arch` depends on libcore, but the contents of this module are
+// set up in such a way that directly pulling it here works such that the
+// crate uses the this crate as its libcore.
+#[path = "../stdsimd/crates/core_arch/src/mod.rs"]
 #[allow(missing_docs, missing_debug_implementations, dead_code, unused_imports)]
 #[unstable(feature = "stdsimd", issue = "48556")]
-mod coresimd;
+mod core_arch;
 
 #[stable(feature = "simd_arch", since = "1.27.0")]
-pub use coresimd::arch;
+pub use core_arch::arch;
diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index 2f350df2f5c18..fdbfa56000b8e 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -1,6 +1,7 @@
-/// Entry point of thread panic, for details, see std::macros
+/// Entry point of thread panic. For details, see `std::macros`.
 #[macro_export]
-#[allow_internal_unstable]
+#[cfg_attr(not(stage0), allow_internal_unstable(core_panic, __rust_unstable_column))]
+#[cfg_attr(stage0, allow_internal_unstable)]
 #[stable(feature = "core", since = "1.6.0")]
 macro_rules! panic {
     () => (
@@ -45,9 +46,12 @@ macro_rules! assert_eq {
         match (&$left, &$right) {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
+                    // The reborrows below are intentional. Without them, the stack slot for the
+                    // borrow is initialized even before the values are compared, leading to a
+                    // noticeable slow down.
                     panic!(r#"assertion failed: `(left == right)`
   left: `{:?}`,
- right: `{:?}`"#, left_val, right_val)
+ right: `{:?}`"#, &*left_val, &*right_val)
                 }
             }
         }
@@ -59,9 +63,12 @@ macro_rules! assert_eq {
         match (&($left), &($right)) {
             (left_val, right_val) => {
                 if !(*left_val == *right_val) {
+                    // The reborrows below are intentional. Without them, the stack slot for the
+                    // borrow is initialized even before the values are compared, leading to a
+                    // noticeable slow down.
                     panic!(r#"assertion failed: `(left == right)`
   left: `{:?}`,
- right: `{:?}`: {}"#, left_val, right_val,
+ right: `{:?}`: {}"#, &*left_val, &*right_val,
                            format_args!($($arg)+))
                 }
             }
@@ -96,9 +103,12 @@ macro_rules! assert_ne {
         match (&$left, &$right) {
             (left_val, right_val) => {
                 if *left_val == *right_val {
+                    // The reborrows below are intentional. Without them, the stack slot for the
+                    // borrow is initialized even before the values are compared, leading to a
+                    // noticeable slow down.
                     panic!(r#"assertion failed: `(left != right)`
   left: `{:?}`,
- right: `{:?}`"#, left_val, right_val)
+ right: `{:?}`"#, &*left_val, &*right_val)
                 }
             }
         }
@@ -110,9 +120,12 @@ macro_rules! assert_ne {
         match (&($left), &($right)) {
             (left_val, right_val) => {
                 if *left_val == *right_val {
+                    // The reborrows below are intentional. Without them, the stack slot for the
+                    // borrow is initialized even before the values are compared, leading to a
+                    // noticeable slow down.
                     panic!(r#"assertion failed: `(left != right)`
   left: `{:?}`,
- right: `{:?}`: {}"#, left_val, right_val,
+ right: `{:?}`: {}"#, &*left_val, &*right_val,
                            format_args!($($arg)+))
                 }
             }
@@ -409,7 +422,8 @@ macro_rules! write {
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(format_args_nl))]
 macro_rules! writeln {
     ($dst:expr) => (
         write!($dst, "\n")
@@ -432,7 +446,7 @@ macro_rules! writeln {
 /// * Iterators that dynamically terminate.
 ///
 /// If the determination that the code is unreachable proves incorrect, the
-/// program immediately terminates with a [`panic!`].  The function [`unreachable_unchecked`],
+/// program immediately terminates with a [`panic!`]. The function [`unreachable_unchecked`],
 /// which belongs to the [`std::hint`] module, informs the compiler to
 /// optimize the code out of the release version entirely.
 ///
@@ -493,7 +507,7 @@ macro_rules! unreachable {
 /// A standardized placeholder for marking unfinished code.
 ///
 /// This can be useful if you are prototyping and are just looking to have your
-/// code typecheck, or if you're implementing a trait that requires multiple
+/// code type-check, or if you're implementing a trait that requires multiple
 /// methods, and you're only planning on using one of them.
 ///
 /// # Panics
@@ -547,6 +561,23 @@ macro_rules! unimplemented {
     ($($arg:tt)+) => (panic!("not yet implemented: {}", format_args!($($arg)*)));
 }
 
+/// A macro to create an array of [`MaybeUninit`]
+///
+/// This macro constructs an uninitialized array of the type `[MaybeUninit<K>; N]`.
+///
+/// [`MaybeUninit`]: mem/union.MaybeUninit.html
+#[macro_export]
+#[unstable(feature = "maybe_uninit_array", issue = "53491")]
+macro_rules! uninitialized_array {
+    // This `into_initialized` is safe because an array of `MaybeUninit` does not
+    // require initialization.
+    // FIXME(#49147): Could be replaced by an array initializer, once those can
+    // be any const expression.
+    ($t:ty; $size:expr) => (unsafe {
+        MaybeUninit::<[MaybeUninit<$t>; $size]>::uninitialized().into_initialized()
+    });
+}
+
 /// Built-in macros to the compiler itself.
 ///
 /// These macros do not have any corresponding definition with a `macro_rules!`
diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index 65752ba032104..29606cb19038f 100644
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -78,7 +78,7 @@ impl<T: ?Sized> !Send for *mut T { }
 ///                         // be made into an object
 /// ```
 ///
-/// [trait object]: ../../book/first-edition/trait-objects.html
+/// [trait object]: ../../book/ch17-02-trait-objects.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[lang = "sized"]
 #[rustc_on_unimplemented(
@@ -518,7 +518,7 @@ macro_rules! impls{
 /// types. We track the Rust type using a phantom type parameter on
 /// the struct `ExternalResource` which wraps a handle.
 ///
-/// [FFI]: ../../book/first-edition/ffi.html
+/// [FFI]: ../../book/ch19-01-unsafe-rust.html#using-extern-functions-to-call-external-code
 ///
 /// ```
 /// # #![allow(dead_code)]
@@ -597,36 +597,46 @@ unsafe impl<T: ?Sized> Freeze for &mut T {}
 
 /// Types which can be safely moved after being pinned.
 ///
-/// Since Rust itself has no notion of immovable types, and will consider moves to always be safe,
+/// Since Rust itself has no notion of immovable types, and considers moves
+/// (e.g. through assignment or [`mem::replace`]) to always be safe,
 /// this trait cannot prevent types from moving by itself.
 ///
-/// Instead it can be used to prevent moves through the type system,
-/// by controlling the behavior of pointers wrapped in the [`Pin`] wrapper,
+/// Instead it is used to prevent moves through the type system,
+/// by controlling the behavior of pointers `P` wrapped in the [`Pin<P>`] wrapper,
 /// which "pin" the type in place by not allowing it to be moved out of them.
 /// See the [`pin module`] documentation for more information on pinning.
 ///
 /// Implementing this trait lifts the restrictions of pinning off a type,
-/// which then allows it to move out with functions such as [`replace`].
+/// which then allows it to move out with functions such as [`mem::replace`].
+///
+/// `Unpin` has no consequence at all for non-pinned data. In particular,
+/// [`mem::replace`] happily moves `!Unpin` data (it works for any `&mut T`, not
+/// just when `T: Unpin`). However, you cannot use
+/// [`mem::replace`] on data wrapped inside a [`Pin<P>`] because you cannot get the
+/// `&mut T` you need for that, and *that* is what makes this system work.
 ///
 /// So this, for example, can only be done on types implementing `Unpin`:
 ///
 /// ```rust
-/// use std::mem::replace;
+/// use std::mem;
 /// use std::pin::Pin;
 ///
 /// let mut string = "this".to_string();
 /// let mut pinned_string = Pin::new(&mut string);
 ///
-/// // dereferencing the pointer mutably is only possible because String implements Unpin
-/// replace(&mut *pinned_string, "other".to_string());
+/// // We need a mutable reference to call `mem::replace`.
+/// // We can obtain such a reference by (implicitly) invoking `Pin::deref_mut`,
+/// // but that is only possible because `String` implements `Unpin`.
+/// mem::replace(&mut *pinned_string, "other".to_string());
 /// ```
 ///
 /// This trait is automatically implemented for almost every type.
 ///
-/// [`replace`]: ../../std/mem/fn.replace.html
-/// [`Pin`]: ../pin/struct.Pin.html
+/// [`mem::replace`]: ../../std/mem/fn.replace.html
+/// [`Pin<P>`]: ../pin/struct.Pin.html
 /// [`pin module`]: ../../std/pin/index.html
 #[stable(feature = "pin", since = "1.33.0")]
+#[cfg_attr(not(stage0), lang = "unpin")]
 pub auto trait Unpin {}
 
 /// A marker type which does not implement `Unpin`.
diff --git a/src/libcore/mem.rs b/src/libcore/mem.rs
index 8fcbb73d9ce46..43afc9a522a30 100644
--- a/src/libcore/mem.rs
+++ b/src/libcore/mem.rs
@@ -15,6 +15,7 @@ use ptr;
 use ops::{Deref, DerefMut};
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[doc(inline)]
 pub use intrinsics::transmute;
 
 /// Takes ownership and "forgets" about the value **without running its destructor**.
@@ -294,11 +295,11 @@ pub const fn size_of<T>() -> usize {
 /// Returns the size of the pointed-to value in bytes.
 ///
 /// This is usually the same as `size_of::<T>()`. However, when `T` *has* no
-/// statically known size, e.g., a slice [`[T]`][slice] or a [trait object],
+/// statically-known size, e.g., a slice [`[T]`][slice] or a [trait object],
 /// then `size_of_val` can be used to get the dynamically-known size.
 ///
 /// [slice]: ../../std/primitive.slice.html
-/// [trait object]: ../../book/first-edition/trait-objects.html
+/// [trait object]: ../../book/ch17-02-trait-objects.html
 ///
 /// # Examples
 ///
@@ -402,7 +403,7 @@ pub fn align_of_val<T: ?Sized>(val: &T) -> usize {
     unsafe { intrinsics::min_align_of_val(val) }
 }
 
-/// Returns whether dropping values of type `T` matters.
+/// Returns `true` if dropping values of type `T` matters.
 ///
 /// This is purely an optimization hint, and may be implemented conservatively:
 /// it may return `true` for types that don't actually need to be dropped.
@@ -489,10 +490,8 @@ pub const fn needs_drop<T>() -> bool {
 /// assert_eq!(0, x);
 /// ```
 #[inline]
-#[rustc_deprecated(since = "2.0.0", reason = "use `mem::MaybeUninit::zeroed` instead")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub unsafe fn zeroed<T>() -> T {
-    #[cfg(not(stage0))]
     intrinsics::panic_if_uninhabited::<T>();
     intrinsics::init()
 }
@@ -626,7 +625,6 @@ pub unsafe fn zeroed<T>() -> T {
 #[rustc_deprecated(since = "2.0.0", reason = "use `mem::MaybeUninit::uninitialized` instead")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub unsafe fn uninitialized<T>() -> T {
-    #[cfg(not(stage0))]
     intrinsics::panic_if_uninhabited::<T>();
     intrinsics::uninit()
 }
@@ -714,8 +712,7 @@ pub fn replace<T>(dest: &mut T, mut src: T) -> T {
 
 /// Disposes of a value.
 ///
-/// While this does call the argument's implementation of [`Drop`][drop],
-/// it will not release any borrows, as borrows are based on lexical scope.
+/// This does call the argument's implementation of [`Drop`][drop].
 ///
 /// This effectively does nothing for types which implement `Copy`, e.g.
 /// integers. Such values are copied and _then_ moved into the function, so the
@@ -742,32 +739,6 @@ pub fn replace<T>(dest: &mut T, mut src: T) -> T {
 /// drop(v); // explicitly drop the vector
 /// ```
 ///
-/// Borrows are based on lexical scope, so this produces an error:
-///
-/// ```compile_fail,E0502
-/// let mut v = vec![1, 2, 3];
-/// let x = &v[0];
-///
-/// drop(x); // explicitly drop the reference, but the borrow still exists
-///
-/// v.push(4); // error: cannot borrow `v` as mutable because it is also
-///            // borrowed as immutable
-/// ```
-///
-/// An inner scope is needed to fix this:
-///
-/// ```
-/// let mut v = vec![1, 2, 3];
-///
-/// {
-///     let x = &v[0];
-///
-///     drop(x); // this is now redundant, as `x` is going out of scope anyway
-/// }
-///
-/// v.push(4); // no problems
-/// ```
-///
 /// Since [`RefCell`] enforces the borrow rules at runtime, `drop` can
 /// release a [`RefCell`] borrow:
 ///
@@ -987,7 +958,7 @@ impl<T> ManuallyDrop<T> {
         ManuallyDrop { value }
     }
 
-    /// Extract the value from the `ManuallyDrop` container.
+    /// Extracts the value from the `ManuallyDrop` container.
     ///
     /// This allows the value to be dropped again.
     ///
@@ -1064,7 +1035,65 @@ impl<T: ?Sized> DerefMut for ManuallyDrop<T> {
     }
 }
 
-/// A newtype to construct uninitialized instances of `T`
+/// A newtype to construct uninitialized instances of `T`.
+///
+/// The compiler, in general, assumes that variables are properly initialized
+/// at their respective type. For example, a variable of reference type must
+/// be aligned and non-NULL. This is an invariant that must *always* be upheld,
+/// even in unsafe code. As a consequence, zero-initializing a variable of reference
+/// type causes instantaneous undefined behavior, no matter whether that reference
+/// ever gets used to access memory:
+///
+/// ```rust,no_run
+/// #![feature(maybe_uninit)]
+/// use std::mem::{self, MaybeUninit};
+///
+/// let x: &i32 = unsafe { mem::zeroed() }; // undefined behavior!
+/// // equivalent code with `MaybeUninit`
+/// let x: &i32 = unsafe { MaybeUninit::zeroed().into_initialized() }; // undefined behavior!
+/// ```
+///
+/// This is exploited by the compiler for various optimizations, such as eliding
+/// run-time checks and optimizing `enum` layout.
+///
+/// Not initializing memory at all (instead of zero-initializing it) causes the same
+/// issue: after all, the initial value of the variable might just happen to be
+/// one that violates the invariant. Moreover, uninitialized memory is special
+/// in that the compiler knows that it does not have a fixed value. This makes
+/// it undefined behavior to have uninitialized data in a variable even if that
+/// variable has otherwise no restrictions about which values are valid:
+///
+/// ```rust,no_run
+/// #![feature(maybe_uninit)]
+/// use std::mem::{self, MaybeUninit};
+///
+/// let x: i32 = unsafe { mem::uninitialized() }; // undefined behavior!
+/// // equivalent code with `MaybeUninit`
+/// let x: i32 = unsafe { MaybeUninit::uninitialized().into_initialized() }; // undefined behavior!
+/// ```
+/// (Notice that the rules around uninitialized integers are not finalized yet, but
+/// until they are, it is advisable to avoid them.)
+///
+/// `MaybeUninit` serves to enable unsafe code to deal with uninitialized data:
+/// it is a signal to the compiler indicating that the data here might *not*
+/// be initialized:
+///
+/// ```rust
+/// #![feature(maybe_uninit)]
+/// use std::mem::MaybeUninit;
+///
+/// // Create an explicitly uninitialized reference. The compiler knows that data inside
+/// // a `MaybeUninit` may be invalid, and hence this is not UB:
+/// let mut x = MaybeUninit::<&i32>::uninitialized();
+/// // Set it to a valid value.
+/// x.set(&0);
+/// // Extract the initialized data -- this is only allowed *after* properly
+/// // initializing `x`!
+/// let x = unsafe { x.into_initialized() };
+/// ```
+///
+/// The compiler then knows to not optimize this code.
+// FIXME before stabilizing, explain how to initialize a struct field-by-field.
 #[allow(missing_debug_implementations)]
 #[unstable(feature = "maybe_uninit", issue = "53491")]
 // NOTE after stabilizing `MaybeUninit` proceed to deprecate `mem::{uninitialized,zeroed}`
@@ -1084,7 +1113,7 @@ impl<T> MaybeUninit<T> {
         MaybeUninit { value: ManuallyDrop::new(val) }
     }
 
-    /// Create a new `MaybeUninit` in an uninitialized state.
+    /// Creates a new `MaybeUninit` in an uninitialized state.
     ///
     /// Note that dropping a `MaybeUninit` will never call `T`'s drop code.
     /// It is your responsibility to make sure `T` gets dropped if it got initialized.
@@ -1094,8 +1123,8 @@ impl<T> MaybeUninit<T> {
         MaybeUninit { uninit: () }
     }
 
-    /// Create a new `MaybeUninit` in an uninitialized state, with the memory being
-    /// filled with `0` bytes.  It depends on `T` whether that already makes for
+    /// Creates a new `MaybeUninit` in an uninitialized state, with the memory being
+    /// filled with `0` bytes. It depends on `T` whether that already makes for
     /// proper initialization. For example, `MaybeUninit<usize>::zeroed()` is initialized,
     /// but `MaybeUninit<&'static i32>::zeroed()` is not because references must not
     /// be null.
@@ -1112,71 +1141,90 @@ impl<T> MaybeUninit<T> {
         u
     }
 
-    /// Set the value of the `MaybeUninit`. This overwrites any previous value without dropping it.
+    /// Sets the value of the `MaybeUninit`. This overwrites any previous value without dropping it.
+    /// For your convenience, this also returns a mutable reference to the (now safely initialized)
+    /// contents of `self`.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
-    pub fn set(&mut self, val: T) {
+    pub fn set(&mut self, val: T) -> &mut T {
         unsafe {
             self.value = ManuallyDrop::new(val);
+            self.get_mut()
         }
     }
 
-    /// Extract the value from the `MaybeUninit` container.  This is a great way
+    /// Gets a pointer to the contained value. Reading from this pointer or turning it
+    /// into a reference will be undefined behavior unless the `MaybeUninit` is initialized.
+    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    #[inline(always)]
+    pub fn as_ptr(&self) -> *const T {
+        unsafe { &*self.value as *const T }
+    }
+
+    /// Gets a mutable pointer to the contained value. Reading from this pointer or turning it
+    /// into a reference will be undefined behavior unless the `MaybeUninit` is initialized.
+    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    #[inline(always)]
+    pub fn as_mut_ptr(&mut self) -> *mut T {
+        unsafe { &mut *self.value as *mut T }
+    }
+
+    /// Extracts the value from the `MaybeUninit` container. This is a great way
     /// to ensure that the data will get dropped, because the resulting `T` is
     /// subject to the usual drop handling.
     ///
     /// # Unsafety
     ///
     /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
-    /// state, otherwise this will immediately cause undefined behavior.
+    /// state. Calling this when the content is not yet fully initialized causes undefined
+    /// behavior.
     #[unstable(feature = "maybe_uninit", issue = "53491")]
     #[inline(always)]
-    pub unsafe fn into_inner(self) -> T {
-        #[cfg(not(stage0))]
+    pub unsafe fn into_initialized(self) -> T {
         intrinsics::panic_if_uninhabited::<T>();
         ManuallyDrop::into_inner(self.value)
     }
 
-    /// Get a reference to the contained value.
+    /// Gets a reference to the contained value.
     ///
     /// # Unsafety
     ///
     /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
-    /// state, otherwise this will immediately cause undefined behavior.
-    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    /// state. Calling this when the content is not yet fully initialized causes undefined
+    /// behavior.
+    #[unstable(feature = "maybe_uninit_ref", issue = "53491")]
     #[inline(always)]
     pub unsafe fn get_ref(&self) -> &T {
         &*self.value
     }
 
-    /// Get a mutable reference to the contained value.
+    /// Gets a mutable reference to the contained value.
     ///
     /// # Unsafety
     ///
     /// It is up to the caller to guarantee that the `MaybeUninit` really is in an initialized
-    /// state, otherwise this will immediately cause undefined behavior.
+    /// state. Calling this when the content is not yet fully initialized causes undefined
+    /// behavior.
     // FIXME(#53491): We currently rely on the above being incorrect, i.e., we have references
     // to uninitialized data (e.g., in `libcore/fmt/float.rs`).  We should make
     // a final decision about the rules before stabilization.
-    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    #[unstable(feature = "maybe_uninit_ref", issue = "53491")]
     #[inline(always)]
     pub unsafe fn get_mut(&mut self) -> &mut T {
         &mut *self.value
     }
 
-    /// Get a pointer to the contained value. Reading from this pointer will be undefined
-    /// behavior unless the `MaybeUninit` is initialized.
-    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    /// Gets a pointer to the first element of the array.
+    #[unstable(feature = "maybe_uninit_slice", issue = "53491")]
     #[inline(always)]
-    pub fn as_ptr(&self) -> *const T {
-        unsafe { &*self.value as *const T }
+    pub fn first_ptr(this: &[MaybeUninit<T>]) -> *const T {
+        this as *const [MaybeUninit<T>] as *const T
     }
 
-    /// Get a mutable pointer to the contained value. Reading from this pointer will be undefined
-    /// behavior unless the `MaybeUninit` is initialized.
-    #[unstable(feature = "maybe_uninit", issue = "53491")]
+    /// Gets a mutable pointer to the first element of the array.
+    #[unstable(feature = "maybe_uninit_slice", issue = "53491")]
     #[inline(always)]
-    pub fn as_mut_ptr(&mut self) -> *mut T {
-        unsafe { &mut *self.value as *mut T }
+    pub fn first_ptr_mut(this: &mut [MaybeUninit<T>]) -> *mut T {
+        this as *mut [MaybeUninit<T>] as *mut T
     }
 }
diff --git a/src/libcore/num/bignum.rs b/src/libcore/num/bignum.rs
index 5326ef1e7c12e..c3a42a0fc0494 100644
--- a/src/libcore/num/bignum.rs
+++ b/src/libcore/num/bignum.rs
@@ -46,17 +46,6 @@ macro_rules! impl_full_ops {
     ($($ty:ty: add($addfn:path), mul/div($bigty:ident);)*) => (
         $(
             impl FullOps for $ty {
-                #[cfg(stage0)]
-                fn full_add(self, other: $ty, carry: bool) -> (bool, $ty) {
-                    // This cannot overflow; the output is between `0` and `2 * 2^nbits - 1`.
-                    // FIXME: will LLVM optimize this into ADC or similar?
-                    let (v, carry1) = unsafe { intrinsics::add_with_overflow(self, other) };
-                    let (v, carry2) = unsafe {
-                        intrinsics::add_with_overflow(v, if carry {1} else {0})
-                    };
-                    (carry1 || carry2, v)
-                }
-                #[cfg(not(stage0))]
                 fn full_add(self, other: $ty, carry: bool) -> (bool, $ty) {
                     // This cannot overflow; the output is between `0` and `2 * 2^nbits - 1`.
                     // FIXME: will LLVM optimize this into ADC or similar?
diff --git a/src/libcore/num/dec2flt/algorithm.rs b/src/libcore/num/dec2flt/algorithm.rs
index d56fa9662a994..3b57bb7544b35 100644
--- a/src/libcore/num/dec2flt/algorithm.rs
+++ b/src/libcore/num/dec2flt/algorithm.rs
@@ -61,7 +61,7 @@ mod fpu_precision {
         unsafe { asm!("fldcw $0" :: "m" (cw) :: "volatile") }
     }
 
-    /// Set the precision field of the FPU to `T` and return a `FPUControlWord`
+    /// Sets the precision field of the FPU to `T` and returns a `FPUControlWord`.
     pub fn set_precision<T>() -> FPUControlWord {
         let cw = 0u16;
 
diff --git a/src/libcore/num/dec2flt/mod.rs b/src/libcore/num/dec2flt/mod.rs
index 58b196a6eac3d..47ea5aa5ff000 100644
--- a/src/libcore/num/dec2flt/mod.rs
+++ b/src/libcore/num/dec2flt/mod.rs
@@ -37,7 +37,7 @@
 //!
 //! In addition, there are numerous helper functions that are used in the paper but not available
 //! in Rust (or at least in core). Our version is additionally complicated by the need to handle
-//! overflow and underflow and the desire to handle subnormal numbers.  Bellerophon and
+//! overflow and underflow and the desire to handle subnormal numbers. Bellerophon and
 //! Algorithm R have trouble with overflow, subnormals, and underflow. We conservatively switch to
 //! Algorithm M (with the modifications described in section 8 of the paper) well before the
 //! inputs get into the critical region.
@@ -54,7 +54,7 @@
 //! operations as well, if you want 0.5 ULP accuracy you need to do *everything* in full precision
 //! and round *exactly once, at the end*, by considering all truncated bits at once.
 //!
-//! FIXME Although some code duplication is necessary, perhaps parts of the code could be shuffled
+//! FIXME: Although some code duplication is necessary, perhaps parts of the code could be shuffled
 //! around such that less code is duplicated. Large parts of the algorithms are independent of the
 //! float type to output, or only needs access to a few constants, which could be passed in as
 //! parameters.
@@ -112,11 +112,35 @@ macro_rules! from_str_float_impl {
             /// * '2.5E10', or equivalently, '2.5e10'
             /// * '2.5E-10'
             /// * '5.'
-            /// * '.5', or, equivalently,  '0.5'
+            /// * '.5', or, equivalently, '0.5'
             /// * 'inf', '-inf', 'NaN'
             ///
             /// Leading and trailing whitespace represent an error.
             ///
+            /// # Grammar
+            ///
+            /// All strings that adhere to the following [EBNF] grammar
+            /// will result in an [`Ok`] being returned:
+            ///
+            /// ```txt
+            /// Float  ::= Sign? ( 'inf' | 'NaN' | Number )
+            /// Number ::= ( Digit+ |
+            ///              Digit+ '.' Digit* |
+            ///              Digit* '.' Digit+ ) Exp?
+            /// Exp    ::= [eE] Sign? Digit+
+            /// Sign   ::= [+-]
+            /// Digit  ::= [0-9]
+            /// ```
+            ///
+            /// [EBNF]: https://www.w3.org/TR/REC-xml/#sec-notation
+            ///
+            /// # Known bugs
+            ///
+            /// In some situations, some strings that should create a valid float
+            /// instead return an error. See [issue #31407] for details.
+            ///
+            /// [issue #31407]: https://github.com/rust-lang/rust/issues/31407
+            ///
             /// # Arguments
             ///
             /// * src - A string
@@ -124,7 +148,7 @@ macro_rules! from_str_float_impl {
             /// # Return value
             ///
             /// `Err(ParseFloatError)` if the string did not represent a valid
-            /// number.  Otherwise, `Ok(n)` where `n` is the floating-point
+            /// number. Otherwise, `Ok(n)` where `n` is the floating-point
             /// number represented by `src`.
             #[inline]
             fn from_str(src: &str) -> Result<Self, ParseFloatError> {
@@ -185,7 +209,7 @@ fn pfe_invalid() -> ParseFloatError {
     ParseFloatError { kind: FloatErrorKind::Invalid }
 }
 
-/// Split decimal string into sign and the rest, without inspecting or validating the rest.
+/// Splits a decimal string into sign and the rest, without inspecting or validating the rest.
 fn extract_sign(s: &str) -> (Sign, &str) {
     match s.as_bytes()[0] {
         b'+' => (Sign::Positive, &s[1..]),
@@ -195,7 +219,7 @@ fn extract_sign(s: &str) -> (Sign, &str) {
     }
 }
 
-/// Convert a decimal string into a floating point number.
+/// Converts a decimal string into a floating point number.
 fn dec2flt<T: RawFloat>(s: &str) -> Result<T, ParseFloatError> {
     if s.is_empty() {
         return Err(pfe_empty())
diff --git a/src/libcore/num/dec2flt/num.rs b/src/libcore/num/dec2flt/num.rs
index b76c58cc66e6b..126713185711b 100644
--- a/src/libcore/num/dec2flt/num.rs
+++ b/src/libcore/num/dec2flt/num.rs
@@ -27,7 +27,7 @@ pub fn compare_with_half_ulp(f: &Big, ones_place: usize) -> Ordering {
     Equal
 }
 
-/// Convert an ASCII string containing only decimal digits to a `u64`.
+/// Converts an ASCII string containing only decimal digits to a `u64`.
 ///
 /// Does not perform checks for overflow or invalid characters, so if the caller is not careful,
 /// the result is bogus and can panic (though it won't be `unsafe`). Additionally, empty strings
@@ -44,7 +44,7 @@ pub fn from_str_unchecked<'a, T>(bytes: T) -> u64 where T : IntoIterator<Item=&'
     result
 }
 
-/// Convert a string of ASCII digits into a bignum.
+/// Converts a string of ASCII digits into a bignum.
 ///
 /// Like `from_str_unchecked`, this function relies on the parser to weed out non-digits.
 pub fn digits_to_big(integral: &[u8], fractional: &[u8]) -> Big {
@@ -69,7 +69,7 @@ pub fn to_u64(x: &Big) -> u64 {
 }
 
 
-/// Extract a range of bits.
+/// Extracts a range of bits.
 
 /// Index 0 is the least significant bit and the range is half-open as usual.
 /// Panics if asked to extract more bits than fit into the return type.
diff --git a/src/libcore/num/dec2flt/parse.rs b/src/libcore/num/dec2flt/parse.rs
index 9e075e43303b6..933f8c1d3f781 100644
--- a/src/libcore/num/dec2flt/parse.rs
+++ b/src/libcore/num/dec2flt/parse.rs
@@ -42,7 +42,7 @@ pub enum ParseResult<'a> {
     Invalid,
 }
 
-/// Check if the input string is a valid floating point number and if so, locate the integral
+/// Checks if the input string is a valid floating point number and if so, locate the integral
 /// part, the fractional part, and the exponent in it. Does not handle signs.
 pub fn parse_decimal(s: &str) -> ParseResult {
     if s.is_empty() {
diff --git a/src/libcore/num/dec2flt/rawfp.rs b/src/libcore/num/dec2flt/rawfp.rs
index 6976bd1a0eefd..b65f539b29c97 100644
--- a/src/libcore/num/dec2flt/rawfp.rs
+++ b/src/libcore/num/dec2flt/rawfp.rs
@@ -59,10 +59,10 @@ pub trait RawFloat
     /// Type used by `to_bits` and `from_bits`.
     type Bits: Add<Output = Self::Bits> + From<u8> + TryFrom<u64>;
 
-    /// Raw transmutation to integer.
+    /// Performs a raw transmutation to an integer.
     fn to_bits(self) -> Self::Bits;
 
-    /// Raw transmutation from integer.
+    /// Performs a raw transmutation from an integer.
     fn from_bits(v: Self::Bits) -> Self;
 
     /// Returns the category that this number falls into.
@@ -71,14 +71,14 @@ pub trait RawFloat
     /// Returns the mantissa, exponent and sign as integers.
     fn integer_decode(self) -> (u64, i16, i8);
 
-    /// Decode the float.
+    /// Decodes the float.
     fn unpack(self) -> Unpacked;
 
-    /// Cast from a small integer that can be represented exactly.  Panic if the integer can't be
+    /// Casts from a small integer that can be represented exactly. Panic if the integer can't be
     /// represented, the other code in this module makes sure to never let that happen.
     fn from_int(x: u64) -> Self;
 
-    /// Get the value 10<sup>e</sup> from a pre-computed table.
+    /// Gets the value 10<sup>e</sup> from a pre-computed table.
     /// Panics for `e >= CEIL_LOG5_OF_MAX_SIG`.
     fn short_fast_pow10(e: usize) -> Self;
 
@@ -240,7 +240,7 @@ impl RawFloat for f64 {
     fn from_bits(v: Self::Bits) -> Self { Self::from_bits(v) }
 }
 
-/// Convert an Fp to the closest machine float type.
+/// Converts an `Fp` to the closest machine float type.
 /// Does not handle subnormal results.
 pub fn fp_to_float<T: RawFloat>(x: Fp) -> T {
     let x = x.normalize();
@@ -319,7 +319,7 @@ pub fn big_to_fp(f: &Big) -> Fp {
     }
 }
 
-/// Find the largest floating point number strictly smaller than the argument.
+/// Finds the largest floating point number strictly smaller than the argument.
 /// Does not handle subnormals, zero, or exponent underflow.
 pub fn prev_float<T: RawFloat>(x: T) -> T {
     match x.classify() {
diff --git a/src/libcore/num/f32.rs b/src/libcore/num/f32.rs
index 68da79135d3a3..dc0580764acb7 100644
--- a/src/libcore/num/f32.rs
+++ b/src/libcore/num/f32.rs
@@ -144,7 +144,7 @@ pub mod consts {
 #[lang = "f32"]
 #[cfg(not(test))]
 impl f32 {
-    /// Returns `true` if this value is `NaN` and false otherwise.
+    /// Returns `true` if this value is `NaN`.
     ///
     /// ```
     /// use std::f32;
@@ -169,8 +169,8 @@ impl f32 {
         f32::from_bits(self.to_bits() & 0x7fff_ffff)
     }
 
-    /// Returns `true` if this value is positive infinity or negative infinity and
-    /// false otherwise.
+    /// Returns `true` if this value is positive infinity or negative infinity, and
+    /// `false` otherwise.
     ///
     /// ```
     /// use std::f32;
@@ -272,7 +272,7 @@ impl f32 {
         }
     }
 
-    /// Returns `true` if and only if `self` has a positive sign, including `+0.0`, `NaN`s with
+    /// Returns `true` if `self` has a positive sign, including `+0.0`, `NaN`s with
     /// positive sign bit and positive infinity.
     ///
     /// ```
@@ -288,7 +288,7 @@ impl f32 {
         !self.is_sign_negative()
     }
 
-    /// Returns `true` if and only if `self` has a negative sign, including `-0.0`, `NaN`s with
+    /// Returns `true` if `self` has a negative sign, including `-0.0`, `NaN`s with
     /// negative sign bit and negative infinity.
     ///
     /// ```
diff --git a/src/libcore/num/f64.rs b/src/libcore/num/f64.rs
index b677391548146..c3677f8c8faea 100644
--- a/src/libcore/num/f64.rs
+++ b/src/libcore/num/f64.rs
@@ -144,7 +144,7 @@ pub mod consts {
 #[lang = "f64"]
 #[cfg(not(test))]
 impl f64 {
-    /// Returns `true` if this value is `NaN` and false otherwise.
+    /// Returns `true` if this value is `NaN`.
     ///
     /// ```
     /// use std::f64;
@@ -169,8 +169,8 @@ impl f64 {
         f64::from_bits(self.to_bits() & 0x7fff_ffff_ffff_ffff)
     }
 
-    /// Returns `true` if this value is positive infinity or negative infinity and
-    /// false otherwise.
+    /// Returns `true` if this value is positive infinity or negative infinity, and
+    /// `false` otherwise.
     ///
     /// ```
     /// use std::f64;
@@ -272,7 +272,7 @@ impl f64 {
         }
     }
 
-    /// Returns `true` if and only if `self` has a positive sign, including `+0.0`, `NaN`s with
+    /// Returns `true` if `self` has a positive sign, including `+0.0`, `NaN`s with
     /// positive sign bit and positive infinity.
     ///
     /// ```
@@ -296,7 +296,7 @@ impl f64 {
         self.is_sign_positive()
     }
 
-    /// Returns `true` if and only if `self` has a negative sign, including `-0.0`, `NaN`s with
+    /// Returns `true` if `self` has a negative sign, including `-0.0`, `NaN`s with
     /// negative sign bit and negative infinity.
     ///
     /// ```
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 6827364c0f805..5b7d5f45d9246 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -10,9 +10,9 @@ use ops;
 use str::FromStr;
 
 macro_rules! impl_nonzero_fmt {
-    ( ( $( $Trait: ident ),+ ) for $Ty: ident ) => {
+    ( #[$stability: meta] ( $( $Trait: ident ),+ ) for $Ty: ident ) => {
         $(
-            #[stable(feature = "nonzero", since = "1.28.0")]
+            #[$stability]
             impl fmt::$Trait for $Ty {
                 #[inline]
                 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -31,7 +31,7 @@ macro_rules! doc_comment {
 }
 
 macro_rules! nonzero_integers {
-    ( $( $Ty: ident($Int: ty); )+ ) => {
+    ( $( #[$stability: meta] $Ty: ident($Int: ty); )+ ) => {
         $(
             doc_comment! {
                 concat!("An integer that is known not to equal zero.
@@ -41,10 +41,10 @@ For example, `Option<", stringify!($Ty), ">` is the same size as `", stringify!(
 
 ```rust
 use std::mem::size_of;
-assert_eq!(size_of::<Option<std::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int),
+assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int),
 ">());
 ```"),
-                #[stable(feature = "nonzero", since = "1.28.0")]
+                #[$stability]
                 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
                 #[repr(transparent)]
                 #[rustc_layout_scalar_valid_range_start(1)]
@@ -52,19 +52,19 @@ assert_eq!(size_of::<Option<std::num::", stringify!($Ty), ">>(), size_of::<", st
             }
 
             impl $Ty {
-                /// Create a non-zero without checking the value.
+                /// Creates a non-zero without checking the value.
                 ///
                 /// # Safety
                 ///
                 /// The value must not be zero.
-                #[stable(feature = "nonzero", since = "1.28.0")]
+                #[$stability]
                 #[inline]
                 pub const unsafe fn new_unchecked(n: $Int) -> Self {
                     $Ty(n)
                 }
 
-                /// Create a non-zero if the given value is not zero.
-                #[stable(feature = "nonzero", since = "1.28.0")]
+                /// Creates a non-zero if the given value is not zero.
+                #[$stability]
                 #[inline]
                 pub fn new(n: $Int) -> Option<Self> {
                     if n != 0 {
@@ -75,7 +75,7 @@ assert_eq!(size_of::<Option<std::num::", stringify!($Ty), ">>(), size_of::<", st
                 }
 
                 /// Returns the value as a primitive type.
-                #[stable(feature = "nonzero", since = "1.28.0")]
+                #[$stability]
                 #[inline]
                 pub const fn get(self) -> $Int {
                     self.0
@@ -91,19 +91,25 @@ assert_eq!(size_of::<Option<std::num::", stringify!($Ty), ">>(), size_of::<", st
             }
 
             impl_nonzero_fmt! {
-                (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
+                #[$stability] (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
             }
         )+
     }
 }
 
 nonzero_integers! {
-    NonZeroU8(u8);
-    NonZeroU16(u16);
-    NonZeroU32(u32);
-    NonZeroU64(u64);
-    NonZeroU128(u128);
-    NonZeroUsize(usize);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU8(u8);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU16(u16);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU32(u32);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU64(u64);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU128(u128);
+    #[stable(feature = "nonzero", since = "1.28.0")] NonZeroUsize(usize);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI8(i8);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI16(i16);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI32(i32);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI64(i64);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI128(i128);
+    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroIsize(isize);
 }
 
 /// Provides intentionally-wrapped arithmetic on `T`.
@@ -275,7 +281,6 @@ $EndFeature, "
 ```
 "),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() }
         }
@@ -291,7 +296,6 @@ Basic usage:
 ", $Feature, "assert_eq!(", stringify!($SelfT), "::max_value().count_zeros(), 1);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn count_zeros(self) -> u32 {
                 (!self).count_ones()
@@ -312,7 +316,6 @@ assert_eq!(n.leading_zeros(), 0);",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn leading_zeros(self) -> u32 {
                 (self as $UnsignedT).leading_zeros()
@@ -333,7 +336,6 @@ assert_eq!(n.trailing_zeros(), 2);",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn trailing_zeros(self) -> u32 {
                 (self as $UnsignedT).trailing_zeros()
@@ -357,7 +359,6 @@ let m = ", $rot_result, ";
 assert_eq!(n.rotate_left(", $rot, "), m);
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_rotate"))]
             #[inline]
             pub const fn rotate_left(self, n: u32) -> Self {
                 (self as $UnsignedT).rotate_left(n) as Self
@@ -382,7 +383,6 @@ let m = ", $rot_op, ";
 assert_eq!(n.rotate_right(", $rot, "), m);
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_rotate"))]
             #[inline]
             pub const fn rotate_right(self, n: u32) -> Self {
                 (self as $UnsignedT).rotate_right(n) as Self
@@ -404,7 +404,6 @@ let m = n.swap_bytes();
 assert_eq!(m, ", $swapped, ");
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn swap_bytes(self) -> Self {
                 (self as $UnsignedT).swap_bytes() as Self
@@ -454,7 +453,6 @@ if cfg!(target_endian = \"big\") {
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn from_be(x: Self) -> Self {
                 #[cfg(target_endian = "big")]
@@ -488,7 +486,6 @@ if cfg!(target_endian = \"little\") {
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn from_le(x: Self) -> Self {
                 #[cfg(target_endian = "little")]
@@ -522,7 +519,6 @@ if cfg!(target_endian = \"big\") {
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn to_be(self) -> Self { // or not to be?
                 #[cfg(target_endian = "big")]
@@ -556,7 +552,6 @@ if cfg!(target_endian = \"little\") {
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn to_le(self) -> Self {
                 #[cfg(target_endian = "little")]
@@ -841,13 +836,12 @@ overflow occurred.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64));
 assert_eq!(", stringify!($SelfT), "::max_value().checked_pow(2), None);",
 $EndFeature, "
 ```"),
 
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn checked_pow(self, mut exp: u32) -> Option<Self> {
                 let mut base = self;
@@ -888,6 +882,7 @@ $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_add(self, rhs: Self) -> Self {
                 match self.checked_add(rhs) {
                     Some(x) => x,
@@ -895,6 +890,31 @@ $EndFeature, "
                     None => Self::min_value(),
                 }
             }
+
+        }
+
+        doc_comment! {
+            concat!("Saturating integer addition. Computes `self + rhs`, saturating at the numeric
+bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);
+assert_eq!(", stringify!($SelfT), "::max_value().saturating_add(100), ", stringify!($SelfT),
+"::max_value());",
+$EndFeature, "
+```"),
+
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_saturating_int_methods")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_add(self, rhs: Self) -> Self {
+                intrinsics::saturating_add(self, rhs)
+            }
         }
 
         doc_comment! {
@@ -913,6 +933,7 @@ $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_sub(self, rhs: Self) -> Self {
                 match self.checked_sub(rhs) {
                     Some(x) => x,
@@ -922,6 +943,29 @@ $EndFeature, "
             }
         }
 
+        doc_comment! {
+            concat!("Saturating integer subtraction. Computes `self - rhs`, saturating at the
+numeric bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);
+assert_eq!(", stringify!($SelfT), "::min_value().saturating_sub(100), ", stringify!($SelfT),
+"::min_value());",
+$EndFeature, "
+```"),
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_saturating_int_methods")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_sub(self, rhs: Self) -> Self {
+                intrinsics::saturating_sub(self, rhs)
+            }
+        }
+
         doc_comment! {
             concat!("Saturating integer multiplication. Computes `self * rhs`, saturating at the
 numeric bounds instead of overflowing.
@@ -960,7 +1004,6 @@ saturating at the numeric bounds instead of overflowing.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "use std::", stringify!($SelfT), ";
 
 assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64);
@@ -968,7 +1011,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT
 assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);",
 $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn saturating_pow(self, exp: u32) -> Self {
                 match self.checked_pow(exp) {
@@ -994,14 +1037,8 @@ assert_eq!(", stringify!($SelfT), "::max_value().wrapping_add(2), ", stringify!(
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_add(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
-                unsafe {
-                    intrinsics::overflowing_add(self, rhs)
-                }
-                #[cfg(not(stage0))]
                 intrinsics::overflowing_add(self, rhs)
             }
         }
@@ -1021,14 +1058,8 @@ stringify!($SelfT), "::max_value());",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_sub(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
-                unsafe {
-                    intrinsics::overflowing_sub(self, rhs)
-                }
-                #[cfg(not(stage0))]
                 intrinsics::overflowing_sub(self, rhs)
             }
         }
@@ -1047,14 +1078,8 @@ assert_eq!(11i8.wrapping_mul(12), -124);",
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_mul(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
-                unsafe {
-                    intrinsics::overflowing_mul(self, rhs)
-                }
-                #[cfg(not(stage0))]
                 intrinsics::overflowing_mul(self, rhs)
             }
         }
@@ -1190,7 +1215,7 @@ $EndFeature, "
 ```"),
             #[stable(feature = "num_wrapping", since = "1.2.0")]
             #[inline]
-            pub fn wrapping_neg(self) -> Self {
+            pub const fn wrapping_neg(self) -> Self {
                 self.overflowing_neg().0
             }
         }
@@ -1214,7 +1239,6 @@ assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(128), -1);",
 $EndFeature, "
 ```"),
             #[stable(feature = "num_wrapping", since = "1.2.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_shl(self, rhs: u32) -> Self {
                 unsafe {
@@ -1242,7 +1266,6 @@ assert_eq!((-128i16).wrapping_shr(64), -128);",
 $EndFeature, "
 ```"),
             #[stable(feature = "num_wrapping", since = "1.2.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_shr(self, rhs: u32) -> Self {
                 unsafe {
@@ -1291,13 +1314,12 @@ wrapping around at the boundary of the type.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81);
 assert_eq!(3i8.wrapping_pow(5), -13);
 assert_eq!(3i8.wrapping_pow(6), -39);",
 $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn wrapping_pow(self, mut exp: u32) -> Self {
                 let mut base = self;
@@ -1340,14 +1362,8 @@ assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($Sel
 "::MIN, true));", $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
-                #[cfg(stage0)]
-                let (a, b) = unsafe {
-                    intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT)
-                };
-                #[cfg(not(stage0))]
                 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
                 (a as Self, b)
             }
@@ -1371,14 +1387,8 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($Sel
 "::MAX, true));", $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
-                #[cfg(stage0)]
-                let (a, b) = unsafe {
-                    intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT)
-                };
-                #[cfg(not(stage0))]
                 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
                 (a as Self, b)
             }
@@ -1400,14 +1410,8 @@ assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));",
 $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
-                #[cfg(stage0)]
-                let (a, b) = unsafe {
-                    intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT)
-                };
-                #[cfg(not(stage0))]
                 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
                 (a as Self, b)
             }
@@ -1565,12 +1569,8 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($Self
 ```"),
             #[inline]
             #[stable(feature = "wrapping", since = "1.7.0")]
-            pub fn overflowing_neg(self) -> (Self, bool) {
-                if self == Self::min_value() {
-                    (Self::min_value(), true)
-                } else {
-                    (-self, false)
-                }
+            pub const fn overflowing_neg(self) -> (Self, bool) {
+                ((!self).wrapping_add(1), self == Self::min_value())
             }
         }
 
@@ -1591,7 +1591,6 @@ assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));",
 $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
                 (self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
@@ -1615,7 +1614,6 @@ assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));",
 $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
                 (self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
@@ -1663,12 +1661,11 @@ whether an overflow happened.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false));
 assert_eq!(3i8.overflowing_pow(5), (-13, true));",
 $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
                 let mut base = self;
@@ -2240,13 +2237,9 @@ Basic usage:
 assert_eq!(n.count_ones(), 3);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn count_ones(self) -> u32 {
-                #[cfg(stage0)]
-                unsafe { intrinsics::ctpop(self as $ActualT) as u32 }
-                #[cfg(not(stage0))]
-                { intrinsics::ctpop(self as $ActualT) as u32 }
+                intrinsics::ctpop(self as $ActualT) as u32
             }
         }
 
@@ -2261,7 +2254,6 @@ Basic usage:
 ", $Feature, "assert_eq!(", stringify!($SelfT), "::max_value().count_zeros(), 0);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn count_zeros(self) -> u32 {
                 (!self).count_ones()
@@ -2281,13 +2273,9 @@ Basic usage:
 assert_eq!(n.leading_zeros(), 2);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn leading_zeros(self) -> u32 {
-                #[cfg(stage0)]
-                unsafe { intrinsics::ctlz(self as $ActualT) as u32 }
-                #[cfg(not(stage0))]
-                { intrinsics::ctlz(self as $ActualT) as u32 }
+                intrinsics::ctlz(self as $ActualT) as u32
             }
         }
 
@@ -2305,13 +2293,9 @@ Basic usage:
 assert_eq!(n.trailing_zeros(), 3);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn trailing_zeros(self) -> u32 {
-                #[cfg(stage0)]
-                unsafe { intrinsics::cttz(self) as u32 }
-                #[cfg(not(stage0))]
-                { intrinsics::cttz(self) as u32 }
+                intrinsics::cttz(self) as u32
             }
         }
 
@@ -2332,12 +2316,8 @@ let m = ", $rot_result, ";
 assert_eq!(n.rotate_left(", $rot, "), m);
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_rotate"))]
             #[inline]
             pub const fn rotate_left(self, n: u32) -> Self {
-                #[cfg(stage0)]
-                unsafe { intrinsics::rotate_left(self, n as $SelfT) }
-                #[cfg(not(stage0))]
                 intrinsics::rotate_left(self, n as $SelfT)
             }
         }
@@ -2360,12 +2340,8 @@ let m = ", $rot_op, ";
 assert_eq!(n.rotate_right(", $rot, "), m);
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_rotate"))]
             #[inline]
             pub const fn rotate_right(self, n: u32) -> Self {
-                #[cfg(stage0)]
-                unsafe { intrinsics::rotate_right(self, n as $SelfT) }
-                #[cfg(not(stage0))]
                 intrinsics::rotate_right(self, n as $SelfT)
             }
         }
@@ -2385,13 +2361,9 @@ let m = n.swap_bytes();
 assert_eq!(m, ", $swapped, ");
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn swap_bytes(self) -> Self {
-                #[cfg(stage0)]
-                unsafe { intrinsics::bswap(self as $ActualT) as Self }
-                #[cfg(not(stage0))]
-                { intrinsics::bswap(self as $ActualT) as Self }
+                intrinsics::bswap(self as $ActualT) as Self
             }
         }
 
@@ -2411,13 +2383,9 @@ let m = n.reverse_bits();
 assert_eq!(m, ", $reversed, ");
 ```"),
             #[unstable(feature = "reverse_bits", issue = "48763")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_conversion"))]
             #[inline]
             pub const fn reverse_bits(self) -> Self {
-                #[cfg(stage0)]
-                unsafe { intrinsics::bitreverse(self as $ActualT) as Self }
-                #[cfg(not(stage0))]
-                { intrinsics::bitreverse(self as $ActualT) as Self }
+                intrinsics::bitreverse(self as $ActualT) as Self
             }
         }
 
@@ -2441,7 +2409,6 @@ if cfg!(target_endian = \"big\") {
 }", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn from_be(x: Self) -> Self {
                 #[cfg(target_endian = "big")]
@@ -2475,7 +2442,6 @@ if cfg!(target_endian = \"little\") {
 }", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn from_le(x: Self) -> Self {
                 #[cfg(target_endian = "little")]
@@ -2509,7 +2475,6 @@ if cfg!(target_endian = \"big\") {
 }", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn to_be(self) -> Self { // or not to be?
                 #[cfg(target_endian = "big")]
@@ -2543,7 +2508,6 @@ if cfg!(target_endian = \"little\") {
 }", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_ops"))]
             #[inline]
             pub const fn to_le(self) -> Self {
                 #[cfg(target_endian = "little")]
@@ -2783,11 +2747,10 @@ overflow occurred.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));
 assert_eq!(", stringify!($SelfT), "::max_value().checked_pow(2), None);", $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn checked_pow(self, mut exp: u32) -> Option<Self> {
                 let mut base = self;
@@ -2826,6 +2789,7 @@ assert_eq!(200u8.saturating_add(127), 255);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_add(self, rhs: Self) -> Self {
                 match self.checked_add(rhs) {
                     Some(x) => x,
@@ -2834,6 +2798,28 @@ assert_eq!(200u8.saturating_add(127), 255);", $EndFeature, "
             }
         }
 
+        doc_comment! {
+            concat!("Saturating integer addition. Computes `self + rhs`, saturating at
+the numeric bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);
+assert_eq!(200u8.saturating_add(127), 255);", $EndFeature, "
+```"),
+
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_saturating_int_methods")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_add(self, rhs: Self) -> Self {
+                intrinsics::saturating_add(self, rhs)
+            }
+        }
+
         doc_comment! {
             concat!("Saturating integer subtraction. Computes `self - rhs`, saturating
 at the numeric bounds instead of overflowing.
@@ -2848,6 +2834,7 @@ assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
             #[inline]
+            #[cfg(stage0)]
             pub fn saturating_sub(self, rhs: Self) -> Self {
                 match self.checked_sub(rhs) {
                     Some(x) => x,
@@ -2856,6 +2843,27 @@ assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
             }
         }
 
+        doc_comment! {
+            concat!("Saturating integer subtraction. Computes `self - rhs`, saturating
+at the numeric bounds instead of overflowing.
+
+# Examples
+
+Basic usage:
+
+```
+", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);
+assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
+```"),
+            #[stable(feature = "rust1", since = "1.0.0")]
+            #[rustc_const_unstable(feature = "const_saturating_int_methods")]
+            #[inline]
+            #[cfg(not(stage0))]
+            pub const fn saturating_sub(self, rhs: Self) -> Self {
+                intrinsics::saturating_sub(self, rhs)
+            }
+        }
+
         doc_comment! {
             concat!("Saturating integer multiplication. Computes `self * rhs`,
 saturating at the numeric bounds instead of overflowing.
@@ -2887,14 +2895,13 @@ saturating at the numeric bounds instead of overflowing.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "use std::", stringify!($SelfT), ";
 
 assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);
 assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);",
 $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn saturating_pow(self, exp: u32) -> Self {
                 match self.checked_pow(exp) {
@@ -2918,14 +2925,8 @@ assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::ma
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_add(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
-                unsafe {
-                    intrinsics::overflowing_add(self, rhs)
-                }
-                #[cfg(not(stage0))]
                 intrinsics::overflowing_add(self, rhs)
             }
         }
@@ -2944,14 +2945,8 @@ assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::ma
 $EndFeature, "
 ```"),
             #[stable(feature = "rust1", since = "1.0.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_sub(self, rhs: Self) -> Self {
-                #[cfg(stage0)]
-                unsafe {
-                    intrinsics::overflowing_sub(self, rhs)
-                }
-                #[cfg(not(stage0))]
                 intrinsics::overflowing_sub(self, rhs)
             }
         }
@@ -2971,14 +2966,8 @@ $EndFeature, "
         /// assert_eq!(25u8.wrapping_mul(12), 44);
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
-        #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
         #[inline]
         pub const fn wrapping_mul(self, rhs: Self) -> Self {
-            #[cfg(stage0)]
-            unsafe {
-                intrinsics::overflowing_mul(self, rhs)
-            }
-            #[cfg(not(stage0))]
             intrinsics::overflowing_mul(self, rhs)
         }
 
@@ -3099,7 +3088,7 @@ assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);
         /// ```
         #[stable(feature = "num_wrapping", since = "1.2.0")]
         #[inline]
-        pub fn wrapping_neg(self) -> Self {
+        pub const fn wrapping_neg(self) -> Self {
             self.overflowing_neg().0
         }
 
@@ -3124,7 +3113,6 @@ Basic usage:
 assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);", $EndFeature, "
 ```"),
             #[stable(feature = "num_wrapping", since = "1.2.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_shl(self, rhs: u32) -> Self {
                 unsafe {
@@ -3154,7 +3142,6 @@ Basic usage:
 assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);", $EndFeature, "
 ```"),
             #[stable(feature = "num_wrapping", since = "1.2.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_wrapping"))]
             #[inline]
             pub const fn wrapping_shr(self, rhs: u32) -> Self {
                 unsafe {
@@ -3172,11 +3159,10 @@ wrapping around at the boundary of the type.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);
 assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn wrapping_pow(self, mut exp: u32) -> Self {
                 let mut base = self;
@@ -3219,14 +3205,8 @@ assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));
 assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));", $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
-                #[cfg(stage0)]
-                let (a, b) = unsafe {
-                    intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT)
-                };
-                #[cfg(not(stage0))]
                 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
                 (a as Self, b)
             }
@@ -3251,14 +3231,8 @@ assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT),
 $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
-                #[cfg(stage0)]
-                let (a, b) = unsafe {
-                    intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT)
-                };
-                #[cfg(not(stage0))]
                 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
                 (a as Self, b)
             }
@@ -3282,14 +3256,8 @@ $EndFeature, "
         /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
         /// ```
         #[stable(feature = "wrapping", since = "1.7.0")]
-        #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
         #[inline]
         pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
-            #[cfg(stage0)]
-            let (a, b) = unsafe {
-                intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT)
-            };
-            #[cfg(not(stage0))]
             let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
             (a as Self, b)
         }
@@ -3425,7 +3393,7 @@ assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!(
 ```"),
             #[inline]
             #[stable(feature = "wrapping", since = "1.7.0")]
-            pub fn overflowing_neg(self) -> (Self, bool) {
+            pub const fn overflowing_neg(self) -> (Self, bool) {
                 ((!self).wrapping_add(1), self != 0)
             }
         }
@@ -3448,7 +3416,6 @@ Basic usage
 assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));", $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
                 (self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
@@ -3473,7 +3440,6 @@ Basic usage
 assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));", $EndFeature, "
 ```"),
             #[stable(feature = "wrapping", since = "1.7.0")]
-            #[cfg_attr(stage0, rustc_const_unstable(feature = "const_int_overflowing"))]
             #[inline]
             pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
                 (self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
@@ -3491,11 +3457,10 @@ whether an overflow happened.
 Basic usage:
 
 ```
-#![feature(no_panic_pow)]
 ", $Feature, "assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));
 assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, "
 ```"),
-            #[unstable(feature = "no_panic_pow", issue = "48320")]
+            #[stable(feature = "no_panic_pow", since = "1.34.0")]
             #[inline]
             pub fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
                 let mut base = self;
diff --git a/src/libcore/ops/arith.rs b/src/libcore/ops/arith.rs
index 7d8bf18d33a01..0252edee23125 100644
--- a/src/libcore/ops/arith.rs
+++ b/src/libcore/ops/arith.rs
@@ -49,7 +49,7 @@
 /// }
 ///
 /// // Notice that the implementation uses the associated type `Output`.
-/// impl<T: Add<Output=T>> Add for Point<T> {
+/// impl<T: Add<Output = T>> Add for Point<T> {
 ///     type Output = Point<T>;
 ///
 ///     fn add(self, other: Point<T>) -> Point<T> {
@@ -157,7 +157,7 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 /// }
 ///
 /// // Notice that the implementation uses the associated type `Output`.
-/// impl<T: Sub<Output=T>> Sub for Point<T> {
+/// impl<T: Sub<Output = T>> Sub for Point<T> {
 ///     type Output = Point<T>;
 ///
 ///     fn sub(self, other: Point<T>) -> Point<T> {
@@ -518,7 +518,7 @@ pub trait Rem<RHS=Self> {
 
 macro_rules! rem_impl_integer {
     ($($t:ty)*) => ($(
-        /// This operation satisfies `n % d == n - (n / d) * d`.  The
+        /// This operation satisfies `n % d == n - (n / d) * d`. The
         /// result has the same sign as the left operand.
         #[stable(feature = "rust1", since = "1.0.0")]
         impl Rem for $t {
diff --git a/src/libcore/ops/deref.rs b/src/libcore/ops/deref.rs
index 075c3a084f41d..eb76c2de11bec 100644
--- a/src/libcore/ops/deref.rs
+++ b/src/libcore/ops/deref.rs
@@ -109,7 +109,7 @@ impl<T: ?Sized> Deref for &mut T {
 /// then:
 ///
 /// * In mutable contexts, `*x` on non-pointer types is equivalent to
-///   `*Deref::deref(&x)`.
+///   `*DerefMut::deref_mut(&mut x)`.
 /// * Values of type `&mut T` are coerced to values of type `&mut U`
 /// * `T` implicitly implements all the (mutable) methods of the type `U`.
 ///
@@ -171,7 +171,7 @@ impl<T: ?Sized> DerefMut for &mut T {
 /// Indicates that a struct can be used as a method receiver, without the
 /// `arbitrary_self_types` feature. This is implemented by stdlib pointer types like `Box<T>`,
 /// `Rc<T>`, `&T`, and `Pin<P>`.
-#[cfg_attr(not(stage0), lang = "receiver")]
+#[lang = "receiver"]
 #[unstable(feature = "receiver_trait", issue = "0")]
 #[doc(hidden)]
 pub trait Receiver {
diff --git a/src/libcore/ops/function.rs b/src/libcore/ops/function.rs
index 3a1d765f7b816..c69f5fd989696 100644
--- a/src/libcore/ops/function.rs
+++ b/src/libcore/ops/function.rs
@@ -62,7 +62,7 @@
     label="expected an `Fn<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
-#[must_use]
+#[must_use = "closures are lazy and do nothing unless called"]
 pub trait Fn<Args> : FnMut<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -141,7 +141,7 @@ pub trait Fn<Args> : FnMut<Args> {
     label="expected an `FnMut<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
-#[must_use]
+#[must_use = "closures are lazy and do nothing unless called"]
 pub trait FnMut<Args> : FnOnce<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
@@ -220,7 +220,7 @@ pub trait FnMut<Args> : FnOnce<Args> {
     label="expected an `FnOnce<{Args}>` closure, found `{Self}`",
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
-#[must_use]
+#[must_use = "closures are lazy and do nothing unless called"]
 pub trait FnOnce<Args> {
     /// The returned type after the call operator is used.
     #[stable(feature = "fn_once_output", since = "1.12.0")]
diff --git a/src/libcore/ops/generator.rs b/src/libcore/ops/generator.rs
index 1542cd6397e78..5401fff860e9b 100644
--- a/src/libcore/ops/generator.rs
+++ b/src/libcore/ops/generator.rs
@@ -1,3 +1,6 @@
+use crate::marker::Unpin;
+use crate::pin::Pin;
+
 /// The result of a generator resumption.
 ///
 /// This enum is returned from the `Generator::resume` method and indicates the
@@ -39,6 +42,7 @@ pub enum GeneratorState<Y, R> {
 /// #![feature(generators, generator_trait)]
 ///
 /// use std::ops::{Generator, GeneratorState};
+/// use std::pin::Pin;
 ///
 /// fn main() {
 ///     let mut generator = || {
@@ -46,11 +50,11 @@ pub enum GeneratorState<Y, R> {
 ///         return "foo"
 ///     };
 ///
-///     match unsafe { generator.resume() } {
+///     match Pin::new(&mut generator).resume() {
 ///         GeneratorState::Yielded(1) => {}
 ///         _ => panic!("unexpected return from resume"),
 ///     }
-///     match unsafe { generator.resume() } {
+///     match Pin::new(&mut generator).resume() {
 ///         GeneratorState::Complete("foo") => {}
 ///         _ => panic!("unexpected return from resume"),
 ///     }
@@ -88,10 +92,6 @@ pub trait Generator {
     /// generator will continue executing until it either yields or returns, at
     /// which point this function will return.
     ///
-    /// The function is unsafe because it can be used on an immovable generator.
-    /// After such a call, the immovable generator must not move again, but
-    /// this is not enforced by the compiler.
-    ///
     /// # Return value
     ///
     /// The `GeneratorState` enum returned from this function indicates what
@@ -110,16 +110,25 @@ pub trait Generator {
     /// been returned previously. While generator literals in the language are
     /// guaranteed to panic on resuming after `Complete`, this is not guaranteed
     /// for all implementations of the `Generator` trait.
-    unsafe fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return>;
+    fn resume(self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return>;
+}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator> Generator for Pin<&mut G> {
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume((*self).as_mut())
+    }
 }
 
 #[unstable(feature = "generator_trait", issue = "43122")]
-impl<T> Generator for &mut T
-    where T: Generator + ?Sized
-{
-    type Yield = T::Yield;
-    type Return = T::Return;
-    unsafe fn resume(&mut self) -> GeneratorState<Self::Yield, Self::Return> {
-        (**self).resume()
+impl<G: ?Sized + Generator + Unpin> Generator for &mut G {
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume(Pin::new(&mut *self))
     }
 }
diff --git a/src/libcore/ops/index.rs b/src/libcore/ops/index.rs
index 4f55c68ecd4ae..d4ed86142768d 100644
--- a/src/libcore/ops/index.rs
+++ b/src/libcore/ops/index.rs
@@ -141,6 +141,21 @@ pub trait Index<Idx: ?Sized> {
 /// ```
 #[lang = "index_mut"]
 #[rustc_on_unimplemented(
+    on(
+        _Self="&str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="str",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    on(
+        _Self="std::string::String",
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
     message="the type `{Self}` cannot be mutably indexed by `{Idx}`",
     label="`{Self}` cannot be mutably indexed by `{Idx}`",
 )]
diff --git a/src/libcore/ops/range.rs b/src/libcore/ops/range.rs
index 815a4cfeed88e..b3dd5d20299c1 100644
--- a/src/libcore/ops/range.rs
+++ b/src/libcore/ops/range.rs
@@ -52,7 +52,7 @@ impl fmt::Debug for RangeFull {
 /// (`start..end`).
 ///
 /// The `Range` `start..end` contains all values with `x >= start` and
-/// `x < end`.  It is empty unless `start < end`.
+/// `x < end`. It is empty unless `start < end`.
 ///
 /// # Examples
 ///
@@ -297,7 +297,7 @@ impl<Idx: PartialOrd<Idx>> RangeTo<Idx> {
 /// A range bounded inclusively below and above (`start..=end`).
 ///
 /// The `RangeInclusive` `start..=end` contains all values with `x >= start`
-/// and `x <= end`.  It is empty unless `start <= end`.
+/// and `x <= end`. It is empty unless `start <= end`.
 ///
 /// This iterator is [fused], but the specific values of `start` and `end` after
 /// iteration has finished are **unspecified** other than that [`.is_empty()`]
diff --git a/src/libcore/ops/try.rs b/src/libcore/ops/try.rs
index 380bd12131cf6..9fa2c81954ee1 100644
--- a/src/libcore/ops/try.rs
+++ b/src/libcore/ops/try.rs
@@ -1,7 +1,7 @@
 /// A trait for customizing the behavior of the `?` operator.
 ///
 /// A type implementing `Try` is one that has a canonical way to view it
-/// in terms of a success/failure dichotomy.  This trait allows both
+/// in terms of a success/failure dichotomy. This trait allows both
 /// extracting those success or failure values from an existing instance and
 /// creating a new instance from a success or failure value.
 #[unstable(feature = "try_trait", issue = "42327")]
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 0e54397db0247..60aed7ce09d7f 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -214,7 +214,7 @@ impl<T> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, preserving the original.
+    /// Converts an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, preserving the original.
     /// The [`map`] method takes the `self` argument by value, consuming the original,
     /// so this technique uses `as_ref` to first take an `Option` to a reference
     /// to the value inside the original.
@@ -395,7 +395,7 @@ impl<T> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, consuming the original:
+    /// Converts an `Option<`[`String`]`>` into an `Option<`[`usize`]`>`, consuming the original:
     ///
     /// [`String`]: ../../std/string/struct.String.html
     /// [`usize`]: ../../std/primitive.usize.html
@@ -874,7 +874,7 @@ impl<T> Option<T> {
     }
 }
 
-impl<'a, T: Copy> Option<&'a T> {
+impl<T: Copy> Option<&T> {
     /// Maps an `Option<&T>` to an `Option<T>` by copying the contents of the
     /// option.
     ///
@@ -895,7 +895,7 @@ impl<'a, T: Copy> Option<&'a T> {
     }
 }
 
-impl<'a, T: Copy> Option<&'a mut T> {
+impl<T: Copy> Option<&mut T> {
     /// Maps an `Option<&mut T>` to an `Option<T>` by copying the contents of the
     /// option.
     ///
@@ -916,7 +916,7 @@ impl<'a, T: Copy> Option<&'a mut T> {
     }
 }
 
-impl<'a, T: Clone> Option<&'a T> {
+impl<T: Clone> Option<&T> {
     /// Maps an `Option<&T>` to an `Option<T>` by cloning the contents of the
     /// option.
     ///
@@ -935,7 +935,7 @@ impl<'a, T: Clone> Option<&'a T> {
     }
 }
 
-impl<'a, T: Clone> Option<&'a mut T> {
+impl<T: Clone> Option<&mut T> {
     /// Maps an `Option<&mut T>` to an `Option<T>` by cloning the contents of the
     /// option.
     ///
@@ -963,7 +963,7 @@ impl<T: Default> Option<T> {
     ///
     /// # Examples
     ///
-    /// Convert a string to an integer, turning poorly-formed strings
+    /// Converts a string to an integer, turning poorly-formed strings
     /// into 0 (the default value for integers). [`parse`] converts
     /// a string to any other type that implements [`FromStr`], returning
     /// [`None`] on error.
diff --git a/src/libcore/pin.rs b/src/libcore/pin.rs
index 762e07549a52a..f9f20dcea9e2e 100644
--- a/src/libcore/pin.rs
+++ b/src/libcore/pin.rs
@@ -2,45 +2,63 @@
 //!
 //! It is sometimes useful to have objects that are guaranteed to not move,
 //! in the sense that their placement in memory does not change, and can thus be relied upon.
-//!
 //! A prime example of such a scenario would be building self-referential structs,
 //! since moving an object with pointers to itself will invalidate them,
 //! which could cause undefined behavior.
 //!
+//! A [`Pin<P>`] ensures that the pointee of any pointer type `P` has a stable location in memory,
+//! meaning it cannot be moved elsewhere and its memory cannot be deallocated
+//! until it gets dropped. We say that the pointee is "pinned".
+//!
 //! By default, all types in Rust are movable. Rust allows passing all types by-value,
-//! and common smart-pointer types such as `Box`, `Rc`, and `&mut` allow replacing and
-//! moving the values they contain. In order to prevent objects from moving, they must
-//! be pinned by wrapping a pointer to the data in the [`Pin`] type.
-//! Doing this prohibits moving the value behind the pointer.
-//! For example, `Pin<Box<T>>` functions much like a regular `Box<T>`,
-//! but doesn't allow moving `T`. The pointer value itself (the `Box`) can still be moved,
-//! but the value behind it cannot.
-//!
-//! Since data can be moved out of `&mut` and `Box` with functions such as [`swap`],
-//! changing the location of the underlying data, [`Pin`] prohibits accessing the
-//! underlying pointer type (the `&mut` or `Box`) directly, and provides its own set of
-//! APIs for accessing and using the value. [`Pin`] also guarantees that no other
-//! functions will move the pointed-to value. This allows for the creation of
-//! self-references and other special behaviors that are only possible for unmovable
-//! values.
+//! and common smart-pointer types such as `Box<T>` and `&mut T` allow replacing and
+//! moving the values they contain: you can move out of a `Box<T>`, or you can use [`mem::swap`].
+//! [`Pin<P>`] wraps a pointer type `P`, so `Pin<Box<T>>` functions much like a regular `Box<T>`:
+//! when a `Pin<Box<T>>` gets dropped, so do its contents, and the memory gets deallocated.
+//! Similarily, `Pin<&mut T>` is a lot like `&mut T`. However, [`Pin<P>`] does not let clients
+//! actually obtain a `Box<T>` or `&mut T` to pinned data, which implies that you cannot use
+//! operations such as [`mem::swap`]:
+//! ```
+//! use std::pin::Pin;
+//! fn swap_pins<T>(x: Pin<&mut T>, y: Pin<&mut T>) {
+//!     // `mem::swap` needs `&mut T`, but we cannot get it.
+//!     // We are stuck, we cannot swap the contents of these references.
+//!     // We could use `Pin::get_unchecked_mut`, but that is unsafe for a reason:
+//!     // we are not allowed to use it for moving things out of the `Pin`.
+//! }
+//! ```
 //!
-//! However, these restrictions are usually not necessary. Many types are always freely
-//! movable. These types implement the [`Unpin`] auto-trait, which nullifies the effect
-//! of [`Pin`]. For `T: Unpin`, `Pin<Box<T>>` and `Box<T>` function identically, as do
-//! `Pin<&mut T>` and `&mut T`.
+//! It is worth reiterating that [`Pin<P>`] does *not* change the fact that a Rust compiler
+//! considers all types movable. [`mem::swap`] remains callable for any `T`. Instead, `Pin<P>`
+//! prevents certain *values* (pointed to by pointers wrapped in `Pin<P>`) from being
+//! moved by making it impossible to call methods that require `&mut T` on them
+//! (like [`mem::swap`]).
 //!
-//! Note that pinning and `Unpin` only affect the pointed-to type. For example, whether
-//! or not `Box<T>` is `Unpin` has no affect on the behavior of `Pin<Box<T>>`. Similarly,
-//! `Pin<Box<T>>` and `Pin<&mut T>` are always `Unpin` themselves, even though the
-//! `T` underneath them isn't, because the pointers in `Pin<Box<_>>` and `Pin<&mut _>`
-//! are always freely movable, even if the data they point to isn't.
+//! [`Pin<P>`] can be used to wrap any pointer type `P`, and as such it interacts with
+//! [`Deref`] and [`DerefMut`]. A `Pin<P>` where `P: Deref` should be considered
+//! as a "`P`-style pointer" to a pinned `P::Target` -- so, a `Pin<Box<T>>` is
+//! an owned pointer to a pinned `T`, and a `Pin<Rc<T>>` is a reference-counted
+//! pointer to a pinned `T`.
+//! For correctness, [`Pin<P>`] relies on the [`Deref`] and [`DerefMut`] implementations
+//! to not move out of their `self` parameter, and to only ever return a pointer
+//! to pinned data when they are called on a pinned pointer.
 //!
-//! [`Pin`]: struct.Pin.html
-//! [`Unpin`]: ../../std/marker/trait.Unpin.html
-//! [`swap`]: ../../std/mem/fn.swap.html
-//! [`Box`]: ../../std/boxed/struct.Box.html
+//! # `Unpin`
+//!
+//! However, these restrictions are usually not necessary. Many types are always freely
+//! movable, even when pinned, because they do not rely on having a stable address.
+//! This includes all the basic types (like `bool`, `i32`, references)
+//! as well as types consisting solely of these types.
+//! Types that do not care about pinning implement the [`Unpin`] auto-trait, which
+//! cancels the effect of [`Pin<P>`]. For `T: Unpin`, `Pin<Box<T>>` and `Box<T>` function
+//! identically, as do `Pin<&mut T>` and `&mut T`.
 //!
-//! # Examples
+//! Note that pinning and `Unpin` only affect the pointed-to type `P::Target`, not the pointer
+//! type `P` itself that got wrapped in `Pin<P>`. For example, whether or not `Box<T>` is
+//! `Unpin` has no effect on the behavior of `Pin<Box<T>>` (here, `T` is the
+//! pointed-to type).
+//!
+//! # Example: self-referential struct
 //!
 //! ```rust
 //! use std::pin::Pin;
@@ -94,11 +112,156 @@
 //! // let new_unmoved = Unmovable::new("world".to_string());
 //! // std::mem::swap(&mut *still_unmoved, &mut *new_unmoved);
 //! ```
+//!
+//! # Example: intrusive doubly-linked list
+//!
+//! In an intrusive doubly-linked list, the collection does not actually allocate
+//! the memory for the elements itself. Allocation is controlled by the clients,
+//! and elements can live on a stack frame that lives shorter than the collection does.
+//!
+//! To make this work, every element has pointers to its predecessor and successor in
+//! the list. Elements can only be added when they are pinned, because moving the elements
+//! around would invalidate the pointers. Moreover, the `Drop` implementation of a linked
+//! list element will patch the pointers of its predecessor and successor to remove itself
+//! from the list.
+//!
+//! Crucially, we have to be able to rely on `drop` being called. If an element
+//! could be deallocated or otherwise invalidated without calling `drop`, the pointers into it
+//! from its neighbouring elements would become invalid, which would break the data structure.
+//!
+//! Therefore, pinning also comes with a `drop`-related guarantee.
+//!
+//! # `Drop` guarantee
+//!
+//! The purpose of pinning is to be able to rely on the placement of some data in memory.
+//! To make this work, not just moving the data is restricted; deallocating, repurposing, or
+//! otherwise invalidating the memory used to store the data is restricted, too.
+//! Concretely, for pinned data you have to maintain the invariant
+//! that *its memory will not get invalidated from the moment it gets pinned until
+//! when `drop` is called*. Memory can be invalidated by deallocation, but also by
+//! replacing a [`Some(v)`] by [`None`], or calling [`Vec::set_len`] to "kill" some elements
+//! off of a vector.
+//!
+//! This is exactly the kind of guarantee that the intrusive linked list from the previous
+//! section needs to function correctly.
+//!
+//! Notice that this guarantee does *not* mean that memory does not leak! It is still
+//! completely okay not to ever call `drop` on a pinned element (e.g., you can still
+//! call [`mem::forget`] on a `Pin<Box<T>>`). In the example of the doubly-linked
+//! list, that element would just stay in the list. However you may not free or reuse the storage
+//! *without calling `drop`*.
+//!
+//! # `Drop` implementation
+//!
+//! If your type uses pinning (such as the two examples above), you have to be careful
+//! when implementing `Drop`. The `drop` function takes `&mut self`, but this
+//! is called *even if your type was previously pinned*! It is as if the
+//! compiler automatically called `get_unchecked_mut`.
+//!
+//! This can never cause a problem in safe code because implementing a type that relies on pinning
+//! requires unsafe code, but be aware that deciding to make use of pinning
+//! in your type (for example by implementing some operation on `Pin<&[mut] Self>`)
+//! has consequences for your `Drop` implementation as well: if an element
+//! of your type could have been pinned, you must treat Drop as implicitly taking
+//! `Pin<&mut Self>`.
+//!
+//! In particular, if your type is `#[repr(packed)]`, the compiler will automatically
+//! move fields around to be able to drop them. As a consequence, you cannot use
+//! pinning with a `#[repr(packed)]` type.
+//!
+//! # Projections and Structural Pinning
+//!
+//! One interesting question arises when considering the interaction of pinning and
+//! the fields of a struct. When can a struct have a "pinning projection", i.e.,
+//! an operation with type `fn(Pin<&[mut] Struct>) -> Pin<&[mut] Field>`?
+//! In a similar vein, when can a generic wrapper type (such as `Vec<T>`, `Box<T>`, or `RefCell<T>`)
+//! have an operation with type `fn(Pin<&[mut] Wrapper<T>>) -> Pin<&[mut] T>`?
+//!
+//! Having a pinning projection for some field means that pinning is "structural":
+//! when the wrapper is pinned, the field must be considered pinned, too.
+//! After all, the pinning projection lets us get a `Pin<&[mut] Field>`.
+//!
+//! However, structural pinning comes with a few extra requirements, so not all
+//! wrappers can be structural and hence not all wrappers can offer pinning projections:
+//!
+//! 1.  The wrapper must only be [`Unpin`] if all the structural fields are
+//!     `Unpin`. This is the default, but `Unpin` is a safe trait, so as the author of
+//!     the wrapper it is your responsibility *not* to add something like
+//!     `impl<T> Unpin for Wrapper<T>`. (Notice that adding a projection operation
+//!     requires unsafe code, so the fact that `Unpin` is a safe trait  does not break
+//!     the principle that you only have to worry about any of this if you use `unsafe`.)
+//! 2.  The destructor of the wrapper must not move structural fields out of its argument. This
+//!     is the exact point that was raised in the [previous section][drop-impl]: `drop` takes
+//!     `&mut self`, but the wrapper (and hence its fields) might have been pinned before.
+//!     You have to guarantee that you do not move a field inside your `Drop` implementation.
+//!     In particular, as explained previously, this means that your wrapper type must *not*
+//!     be `#[repr(packed)]`.
+//! 3.  You must make sure that you uphold the [`Drop` guarantee][drop-guarantee]:
+//!     once your wrapper is pinned, the memory that contains the
+//!     content is not overwritten or deallocated without calling the content's destructors.
+//!     This can be tricky, as witnessed by `VecDeque<T>`: the destructor of `VecDeque<T>` can fail
+//!     to call `drop` on all elements if one of the destructors panics. This violates the
+//!     `Drop` guarantee, because it can lead to elements being deallocated without
+//!     their destructor being called. (`VecDeque` has no pinning projections, so this
+//!     does not cause unsoundness.)
+//! 4.  You must not offer any other operations that could lead to data being moved out of
+//!     the fields when your type is pinned. For example, if the wrapper contains an
+//!     `Option<T>` and there is a `take`-like operation with type
+//!     `fn(Pin<&mut Wrapper<T>>) -> Option<T>`,
+//!     that operation can be used to move a `T` out of a pinned `Wrapper<T>` -- which means
+//!     pinning cannot be structural.
+//!
+//!     For a more complex example of moving data out of a pinned type, imagine if `RefCell<T>`
+//!     had a method `fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T>`.
+//!     Then we could do the following:
+//!     ```compile_fail
+//!     fn exploit_ref_cell<T>(rc: Pin<&mut RefCell<T>) {
+//!         { let p = rc.as_mut().get_pin_mut(); } // Here we get pinned access to the `T`.
+//!         let rc_shr: &RefCell<T> = rc.into_ref().get_ref();
+//!         let b = rc_shr.borrow_mut();
+//!         let content = &mut *b; // And here we have `&mut T` to the same data.
+//!     }
+//!     ```
+//!     This is catastrophic, it means we can first pin the content of the `RefCell<T>`
+//!     (using `RefCell::get_pin_mut`) and then move that content using the mutable
+//!     reference we got later.
+//!
+//! For a type like `Vec<T>`, both possibilites (structural pinning or not) make sense,
+//! and the choice is up to the author. A `Vec<T>` with structural pinning could
+//! have `get_pin`/`get_pin_mut` projections. However, it could *not* allow calling
+//! `pop` on a pinned `Vec<T>` because that would move the (structurally pinned) contents!
+//! Nor could it allow `push`, which might reallocate and thus also move the contents.
+//! A `Vec<T>` without structural pinning could `impl<T> Unpin for Vec<T>`, because the contents
+//! are never pinned and the `Vec<T>` itself is fine with being moved as well.
+//!
+//! In the standard library, pointer types generally do not have structural pinning,
+//! and thus they do not offer pinning projections. This is why `Box<T>: Unpin` holds for all `T`.
+//! It makes sense to do this for pointer types, because moving the `Box<T>`
+//! does not actually move the `T`: the `Box<T>` can be freely movable (aka `Unpin`) even if the `T`
+//! is not. In fact, even `Pin<Box<T>>` and `Pin<&mut T>` are always `Unpin` themselves,
+//! for the same reason: their contents (the `T`) are pinned, but the pointers themselves
+//! can be moved without moving the pinned data. For both `Box<T>` and `Pin<Box<T>>`,
+//! whether the content is pinned is entirely independent of whether the pointer is
+//! pinned, meaning pinning is *not* structural.
+//!
+//! [`Pin<P>`]: struct.Pin.html
+//! [`Unpin`]: ../../std/marker/trait.Unpin.html
+//! [`Deref`]: ../../std/ops/trait.Deref.html
+//! [`DerefMut`]: ../../std/ops/trait.DerefMut.html
+//! [`mem::swap`]: ../../std/mem/fn.swap.html
+//! [`mem::forget`]: ../../std/mem/fn.forget.html
+//! [`Box<T>`]: ../../std/boxed/struct.Box.html
+//! [`Vec::set_len`]: ../../std/vec/struct.Vec.html#method.set_len
+//! [`None`]: ../../std/option/enum.Option.html#variant.None
+//! [`Some(v)`]: ../../std/option/enum.Option.html#variant.Some
+//! [drop-impl]: #drop-implementation
+//! [drop-guarantee]: #drop-guarantee
 
 #![stable(feature = "pin", since = "1.33.0")]
 
 use fmt;
 use marker::{Sized, Unpin};
+use cmp::{self, PartialEq, PartialOrd};
 use ops::{Deref, DerefMut, Receiver, CoerceUnsized, DispatchFromDyn};
 
 /// A pinned pointer.
@@ -112,22 +275,69 @@ use ops::{Deref, DerefMut, Receiver, CoerceUnsized, DispatchFromDyn};
 /// [`Unpin`]: ../../std/marker/trait.Unpin.html
 /// [`pin` module]: ../../std/pin/index.html
 //
-// Note: the derives below are allowed because they all only use `&P`, so they
-// cannot move the value behind `pointer`.
+// Note: the derives below, and the explicit `PartialEq` and `PartialOrd`
+// implementations, are allowed because they all only use `&P`, so they cannot move
+// the value behind `pointer`.
 #[stable(feature = "pin", since = "1.33.0")]
+#[cfg_attr(not(stage0), lang = "pin")]
 #[fundamental]
 #[repr(transparent)]
-#[derive(Copy, Clone, Hash, Eq, PartialEq, Ord, PartialOrd)]
+#[derive(Copy, Clone, Hash, Eq, Ord)]
 pub struct Pin<P> {
     pointer: P,
 }
 
+#[stable(feature = "pin_partialeq_partialord_impl_applicability", since = "1.34.0")]
+impl<P, Q> PartialEq<Pin<Q>> for Pin<P>
+where
+    P: PartialEq<Q>,
+{
+    fn eq(&self, other: &Pin<Q>) -> bool {
+        self.pointer == other.pointer
+    }
+
+    fn ne(&self, other: &Pin<Q>) -> bool {
+        self.pointer != other.pointer
+    }
+}
+
+#[stable(feature = "pin_partialeq_partialord_impl_applicability", since = "1.34.0")]
+impl<P, Q> PartialOrd<Pin<Q>> for Pin<P>
+where
+    P: PartialOrd<Q>,
+{
+    fn partial_cmp(&self, other: &Pin<Q>) -> Option<cmp::Ordering> {
+        self.pointer.partial_cmp(&other.pointer)
+    }
+
+    fn lt(&self, other: &Pin<Q>) -> bool {
+        self.pointer < other.pointer
+    }
+
+    fn le(&self, other: &Pin<Q>) -> bool {
+        self.pointer <= other.pointer
+    }
+
+    fn gt(&self, other: &Pin<Q>) -> bool {
+        self.pointer > other.pointer
+    }
+
+    fn ge(&self, other: &Pin<Q>) -> bool {
+        self.pointer >= other.pointer
+    }
+}
+
 impl<P: Deref> Pin<P>
 where
     P::Target: Unpin,
 {
-    /// Construct a new `Pin` around a pointer to some data of a type that
-    /// implements `Unpin`.
+    /// Construct a new `Pin<P>` around a pointer to some data of a type that
+    /// implements [`Unpin`].
+    ///
+    /// Unlike `Pin::new_unchecked`, this method is safe because the pointer
+    /// `P` dereferences to an [`Unpin`] type, which cancels the pinning guarantees.
+    ///
+    /// [`Unpin`]: ../../std/marker/trait.Unpin.html
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn new(pointer: P) -> Pin<P> {
@@ -138,25 +348,83 @@ where
 }
 
 impl<P: Deref> Pin<P> {
-    /// Construct a new `Pin` around a reference to some data of a type that
+    /// Construct a new `Pin<P>` around a reference to some data of a type that
     /// may or may not implement `Unpin`.
     ///
+    /// If `pointer` dereferences to an `Unpin` type, `Pin::new` should be used
+    /// instead.
+    ///
     /// # Safety
     ///
     /// This constructor is unsafe because we cannot guarantee that the data
-    /// pointed to by `pointer` is pinned. If the constructed `Pin<P>` does
-    /// not guarantee that the data `P` points to is pinned, constructing a
-    /// `Pin<P>` is undefined behavior.
+    /// pointed to by `pointer` is pinned, meaning that the data will not be moved or
+    /// its storage invalidated until it gets dropped. If the constructed `Pin<P>` does
+    /// not guarantee that the data `P` points to is pinned, that is a violation of
+    /// the API contract and may lead to undefined behavior in later (safe) operations.
     ///
-    /// If `pointer` dereferences to an `Unpin` type, `Pin::new` should be used
-    /// instead.
+    /// By using this method, you are making a promise about the `P::Deref` and
+    /// `P::DerefMut` implementations, if they exist. Most importantly, they
+    /// must not move out of their `self` arguments: `Pin::as_mut` and `Pin::as_ref`
+    /// will call `DerefMut::deref_mut` and `Deref::deref` *on the pinned pointer*
+    /// and expect these methods to uphold the pinning invariants.
+    /// Moreover, by calling this method you promise that the reference `P`
+    /// dereferences to will not be moved out of again; in particular, it
+    /// must not be possible to obtain a `&mut P::Target` and then
+    /// move out of that reference (using, for example [`mem::swap`]).
+    ///
+    /// For example, calling `Pin::new_unchecked` on an `&'a mut T` is unsafe because
+    /// while you are able to pin it for the given lifetime `'a`, you have no control
+    /// over whether it is kept pinned once `'a` ends:
+    /// ```
+    /// use std::mem;
+    /// use std::pin::Pin;
+    ///
+    /// fn move_pinned_ref<T>(mut a: T, mut b: T) {
+    ///     unsafe {
+    ///         let p: Pin<&mut T> = Pin::new_unchecked(&mut a);
+    ///         // This should mean the pointee `a` can never move again.
+    ///     }
+    ///     mem::swap(&mut a, &mut b);
+    ///     // The address of `a` changed to `b`'s stack slot, so `a` got moved even
+    ///     // though we have previously pinned it! We have violated the pinning API contract.
+    /// }
+    /// ```
+    /// A value, once pinned, must remain pinned forever (unless its type implements `Unpin`).
+    ///
+    /// Similarily, calling `Pin::new_unchecked` on an `Rc<T>` is unsafe because there could be
+    /// aliases to the same data that are not subject to the pinning restrictions:
+    /// ```
+    /// use std::rc::Rc;
+    /// use std::pin::Pin;
+    ///
+    /// fn move_pinned_rc<T>(mut x: Rc<T>) {
+    ///     let pinned = unsafe { Pin::new_unchecked(x.clone()) };
+    ///     {
+    ///         let p: Pin<&T> = pinned.as_ref();
+    ///         // This should mean the pointee can never move again.
+    ///     }
+    ///     drop(pinned);
+    ///     let content = Rc::get_mut(&mut x).unwrap();
+    ///     // Now, if `x` was the only reference, we have a mutable reference to
+    ///     // data that we pinned above, which we could use to move it as we have
+    ///     // seen in the previous example. We have violated the pinning API contract.
+    ///  }
+    ///  ```
+    ///
+    /// [`mem::swap`]: ../../std/mem/fn.swap.html
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub unsafe fn new_unchecked(pointer: P) -> Pin<P> {
         Pin { pointer }
     }
 
-    /// Get a pinned shared reference from this pinned pointer.
+    /// Gets a pinned shared reference from this pinned pointer.
+    ///
+    /// This is a generic method to go from `&Pin<Pointer<T>>` to `Pin<&T>`.
+    /// It is safe because, as part of the contract of `Pin::new_unchecked`,
+    /// the pointee cannot move after `Pin<Pointer<T>>` got created.
+    /// "Malicious" implementations of `Pointer::Deref` are likewise
+    /// ruled out by the contract of `Pin::new_unchecked`.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn as_ref(self: &Pin<P>) -> Pin<&P::Target> {
@@ -165,14 +433,23 @@ impl<P: Deref> Pin<P> {
 }
 
 impl<P: DerefMut> Pin<P> {
-    /// Get a pinned mutable reference from this pinned pointer.
+    /// Gets a pinned mutable reference from this pinned pointer.
+    ///
+    /// This is a generic method to go from `&mut Pin<Pointer<T>>` to `Pin<&mut T>`.
+    /// It is safe because, as part of the contract of `Pin::new_unchecked`,
+    /// the pointee cannot move after `Pin<Pointer<T>>` got created.
+    /// "Malicious" implementations of `Pointer::DerefMut` are likewise
+    /// ruled out by the contract of `Pin::new_unchecked`.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn as_mut(self: &mut Pin<P>) -> Pin<&mut P::Target> {
         unsafe { Pin::new_unchecked(&mut *self.pointer) }
     }
 
-    /// Assign a new value to the memory behind the pinned reference.
+    /// Assigns a new value to the memory behind the pinned reference.
+    ///
+    /// This overwrites pinned data, but that is okay: its destructor gets
+    /// run before being overwritten, so no pinning guarantee is violated.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn set(self: &mut Pin<P>, value: P::Target)
@@ -184,10 +461,12 @@ impl<P: DerefMut> Pin<P> {
 }
 
 impl<'a, T: ?Sized> Pin<&'a T> {
-    /// Construct a new pin by mapping the interior value.
+    /// Constructs a new pin by mapping the interior value.
     ///
     /// For example, if you  wanted to get a `Pin` of a field of something,
     /// you could use this to get access to that field in one line of code.
+    /// However, there are several gotchas with these "pinning projections";
+    /// see the [`pin` module] documentation for further details on that topic.
     ///
     /// # Safety
     ///
@@ -195,6 +474,8 @@ impl<'a, T: ?Sized> Pin<&'a T> {
     /// will not move so long as the argument value does not move (for example,
     /// because it is one of the fields of that value), and also that you do
     /// not move out of the argument you receive to the interior function.
+    ///
+    /// [`pin` module]: ../../std/pin/index.html#projections-and-structural-pinning
     #[stable(feature = "pin", since = "1.33.0")]
     pub unsafe fn map_unchecked<U, F>(self: Pin<&'a T>, func: F) -> Pin<&'a U> where
         F: FnOnce(&T) -> &U,
@@ -204,13 +485,23 @@ impl<'a, T: ?Sized> Pin<&'a T> {
         Pin::new_unchecked(new_pointer)
     }
 
-    /// Get a shared reference out of a pin.
+    /// Gets a shared reference out of a pin.
+    ///
+    /// This is safe because it is not possible to move out of a shared reference.
+    /// It may seem like there is an issue here with interior mutability: in fact,
+    /// it *is* possible to move a `T` out of a `&RefCell<T>`. However, this is
+    /// not a problem as long as there does not also exist a `Pin<&T>` pointing
+    /// to the same data, and `RefCell<T>` does not let you create a pinned reference
+    /// to its contents. See the discussion on ["pinning projections"] for further
+    /// details.
     ///
     /// Note: `Pin` also implements `Deref` to the target, which can be used
     /// to access the inner value. However, `Deref` only provides a reference
     /// that lives for as long as the borrow of the `Pin`, not the lifetime of
     /// the `Pin` itself. This method allows turning the `Pin` into a reference
     /// with the same lifetime as the original `Pin`.
+    ///
+    /// ["pinning projections"]: ../../std/pin/index.html#projections-and-structural-pinning
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn get_ref(self: Pin<&'a T>) -> &'a T {
@@ -219,14 +510,14 @@ impl<'a, T: ?Sized> Pin<&'a T> {
 }
 
 impl<'a, T: ?Sized> Pin<&'a mut T> {
-    /// Convert this `Pin<&mut T>` into a `Pin<&T>` with the same lifetime.
+    /// Converts this `Pin<&mut T>` into a `Pin<&T>` with the same lifetime.
     #[stable(feature = "pin", since = "1.33.0")]
     #[inline(always)]
     pub fn into_ref(self: Pin<&'a mut T>) -> Pin<&'a T> {
         Pin { pointer: self.pointer }
     }
 
-    /// Get a mutable reference to the data inside of this `Pin`.
+    /// Gets a mutable reference to the data inside of this `Pin`.
     ///
     /// This requires that the data inside this `Pin` is `Unpin`.
     ///
@@ -243,7 +534,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
         self.pointer
     }
 
-    /// Get a mutable reference to the data inside of this `Pin`.
+    /// Gets a mutable reference to the data inside of this `Pin`.
     ///
     /// # Safety
     ///
@@ -263,6 +554,8 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
     ///
     /// For example, if you  wanted to get a `Pin` of a field of something,
     /// you could use this to get access to that field in one line of code.
+    /// However, there are several gotchas with these "pinning projections";
+    /// see the [`pin` module] documentation for further details on that topic.
     ///
     /// # Safety
     ///
@@ -270,6 +563,8 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
     /// will not move so long as the argument value does not move (for example,
     /// because it is one of the fields of that value), and also that you do
     /// not move out of the argument you receive to the interior function.
+    ///
+    /// [`pin` module]: ../../std/pin/index.html#projections-and-structural-pinning
     #[stable(feature = "pin", since = "1.33.0")]
     pub unsafe fn map_unchecked_mut<U, F>(self: Pin<&'a mut T>, func: F) -> Pin<&'a mut U> where
         F: FnOnce(&mut T) -> &mut U,
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index 02eef07afd7ab..866c8d0896b3c 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -12,7 +12,7 @@
 //! to access only a single value, in which case the documentation omits the size
 //! and implicitly assumes it to be `size_of::<T>()` bytes.
 //!
-//! The precise rules for validity are not determined yet.  The guarantees that are
+//! The precise rules for validity are not determined yet. The guarantees that are
 //! provided at this point are very minimal:
 //!
 //! * A [null] pointer is *never* valid, not even for accesses of [size zero][zst].
@@ -104,7 +104,7 @@ pub use intrinsics::write_bytes;
 ///
 /// * `to_drop` must be [valid] for reads.
 ///
-/// * `to_drop` must be properly aligned.  See the example below for how to drop
+/// * `to_drop` must be properly aligned. See the example below for how to drop
 ///   an unaligned pointer.
 ///
 /// Additionally, if `T` is not [`Copy`], using the pointed-to value after
@@ -135,7 +135,7 @@ pub use intrinsics::write_bytes;
 /// unsafe {
 ///     // Get a raw pointer to the last element in `v`.
 ///     let ptr = &mut v[1] as *mut _;
-///     // Shorten `v` to prevent the last item from being dropped.  We do that first,
+///     // Shorten `v` to prevent the last item from being dropped. We do that first,
 ///     // to prevent issues if the `drop_in_place` below panics.
 ///     v.set_len(1);
 ///     // Without a call `drop_in_place`, the last item would never be dropped,
@@ -531,7 +531,7 @@ pub unsafe fn replace<T>(dst: *mut T, mut src: T) -> T {
 ///
 /// `read` creates a bitwise copy of `T`, regardless of whether `T` is [`Copy`].
 /// If `T` is not [`Copy`], using both the returned value and the value at
-/// `*src` can violate memory safety.  Note that assigning to `*src` counts as a
+/// `*src` can violate memory safety. Note that assigning to `*src` counts as a
 /// use because it will attempt to drop the value at `*src`.
 ///
 /// [`write`] can be used to overwrite data without causing it to be dropped.
@@ -573,7 +573,7 @@ pub unsafe fn replace<T>(dst: *mut T, mut src: T) -> T {
 pub unsafe fn read<T>(src: *const T) -> T {
     let mut tmp = MaybeUninit::<T>::uninitialized();
     copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
-    tmp.into_inner()
+    tmp.into_initialized()
 }
 
 /// Reads the value from `src` without moving it. This leaves the
@@ -588,7 +588,7 @@ pub unsafe fn read<T>(src: *const T) -> T {
 /// * `src` must be [valid] for reads.
 ///
 /// Like [`read`], `read_unaligned` creates a bitwise copy of `T`, regardless of
-/// whether `T` is [`Copy`].  If `T` is not [`Copy`], using both the returned
+/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using both the returned
 /// value and the value at `*src` can [violate memory safety][read-ownership].
 ///
 /// Note that even if `T` has size `0`, the pointer must be non-NULL.
@@ -642,7 +642,7 @@ pub unsafe fn read_unaligned<T>(src: *const T) -> T {
     copy_nonoverlapping(src as *const u8,
                         tmp.as_mut_ptr() as *mut u8,
                         mem::size_of::<T>());
-    tmp.into_inner()
+    tmp.into_initialized()
 }
 
 /// Overwrites a memory location with the given value without reading or
@@ -825,7 +825,7 @@ pub unsafe fn write_unaligned<T>(dst: *mut T, src: T) {
 ///
 /// The compiler shouldn't change the relative order or number of volatile
 /// memory operations. However, volatile memory operations on zero-sized types
-/// (e.g., if a zero-sized type is passed to `read_volatile`) are no-ops
+/// (e.g., if a zero-sized type is passed to `read_volatile`) are noops
 /// and may be ignored.
 ///
 /// [c11]: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
@@ -839,7 +839,7 @@ pub unsafe fn write_unaligned<T>(dst: *mut T, src: T) {
 /// * `src` must be properly aligned.
 ///
 /// Like [`read`], `read_unaligned` creates a bitwise copy of `T`, regardless of
-/// whether `T` is [`Copy`].  If `T` is not [`Copy`], using both the returned
+/// whether `T` is [`Copy`]. If `T` is not [`Copy`], using both the returned
 /// value and the value at `*src` can [violate memory safety][read-ownership].
 /// However, storing non-[`Copy`] types in volatile memory is almost certainly
 /// incorrect.
@@ -903,7 +903,7 @@ pub unsafe fn read_volatile<T>(src: *const T) -> T {
 ///
 /// The compiler shouldn't change the relative order or number of volatile
 /// memory operations. However, volatile memory operations on zero-sized types
-/// (e.g., if a zero-sized type is passed to `write_volatile`) are no-ops
+/// (e.g., if a zero-sized type is passed to `write_volatile`) are noops
 /// and may be ignored.
 ///
 /// [c11]: http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
@@ -1093,7 +1093,7 @@ impl<T: ?Sized> *const T {
     /// unless `x` and `y` point into the same allocated object.
     ///
     /// Always use `.offset(count)` instead when possible, because `offset`
-    /// allows the compiler to optimize better.  If you need to cross object
+    /// allows the compiler to optimize better. If you need to cross object
     /// boundaries, cast the pointer to an integer and do the arithmetic there.
     ///
     /// # Examples
@@ -1712,7 +1712,7 @@ impl<T: ?Sized> *mut T {
     /// unless `x` and `y` point into the same allocated object.
     ///
     /// Always use `.offset(count)` instead when possible, because `offset`
-    /// allows the compiler to optimize better.  If you need to cross object
+    /// allows the compiler to optimize better. If you need to cross object
     /// boundaries, cast the pointer to an integer and do the arithmetic there.
     ///
     /// # Examples
@@ -2473,7 +2473,7 @@ impl<T: ?Sized> PartialEq for *mut T {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> Eq for *mut T {}
 
-/// Compare raw pointers for equality.
+/// Compares raw pointers for equality.
 ///
 /// This is the same as using the `==` operator, but less generic:
 /// the arguments have to be `*const T` raw pointers,
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index 1ebf0714e23e4..92d29f6ee8a30 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -896,7 +896,7 @@ impl<T: Default, E> Result<T, E> {
     ///
     /// # Examples
     ///
-    /// Convert a string to an integer, turning poorly-formed strings
+    /// Converts a string to an integer, turning poorly-formed strings
     /// into 0 (the default value for integers). [`parse`] converts
     /// a string to any other type that implements [`FromStr`], returning an
     /// [`Err`] on error.
diff --git a/src/libcore/slice/memchr.rs b/src/libcore/slice/memchr.rs
index 312838a170c6b..cbba546b8daba 100644
--- a/src/libcore/slice/memchr.rs
+++ b/src/libcore/slice/memchr.rs
@@ -11,7 +11,7 @@ const HI_U64: u64 = 0x8080808080808080;
 const LO_USIZE: usize = LO_U64 as usize;
 const HI_USIZE: usize = HI_U64 as usize;
 
-/// Returns whether `x` contains any zero byte.
+/// Returns `true` if `x` contains any zero byte.
 ///
 /// From *Matters Computational*, J. Arndt:
 ///
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index 7fdc2acb8cc92..d89443662df87 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -34,7 +34,6 @@ use result::Result::{Ok, Err};
 use ptr;
 use mem;
 use marker::{Copy, Send, Sync, Sized, self};
-use iter_private::TrustedRandomAccess;
 
 #[unstable(feature = "slice_internals", issue = "0",
            reason = "exposed from core to be reused in std; use the memchr crate")]
@@ -1198,7 +1197,7 @@ impl<T> [T] {
 
     /// Returns an iterator over subslices separated by elements that match
     /// `pred` limited to returning at most `n` items. This starts at the end of
-    /// the slice and works backwards.  The matched element is not contained in
+    /// the slice and works backwards. The matched element is not contained in
     /// the subslices.
     ///
     /// The last element returned, if any, will contain the remainder of the
@@ -1564,6 +1563,10 @@ impl<T> [T] {
     /// randomization to avoid degenerate cases, but with a fixed seed to always provide
     /// deterministic behavior.
     ///
+    /// Due to its key calling strategy, [`sort_unstable_by_key`](#method.sort_unstable_by_key)
+    /// is likely to be slower than [`sort_by_cached_key`](#method.sort_by_cached_key) in
+    /// cases where the key function is expensive.
+    ///
     /// # Examples
     ///
     /// ```
@@ -1783,7 +1786,7 @@ impl<T> [T] {
     /// let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
     /// a[1..5].rotate_left(1);
     /// assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);
-   /// ```
+    /// ```
     #[stable(feature = "slice_rotate", since = "1.26.0")]
     pub fn rotate_left(&mut self, mid: usize) {
         assert!(mid <= self.len());
@@ -2250,6 +2253,77 @@ impl<T> [T] {
              from_raw_parts_mut(mut_ptr.add(rest.len() - ts_len), ts_len))
         }
     }
+
+    /// Checks if the elements of this slice are sorted.
+    ///
+    /// That is, for each element `a` and its following element `b`, `a <= b` must hold. If the
+    /// slice yields exactly zero or one element, `true` is returned.
+    ///
+    /// Note that if `Self::Item` is only `PartialOrd`, but not `Ord`, the above definition
+    /// implies that this function returns `false` if any two consecutive items are not
+    /// comparable.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_sorted)]
+    /// let empty: [i32; 0] = [];
+    ///
+    /// assert!([1, 2, 2, 9].is_sorted());
+    /// assert!(![1, 3, 2, 4].is_sorted());
+    /// assert!([0].is_sorted());
+    /// assert!(empty.is_sorted());
+    /// assert!(![0.0, 1.0, std::f32::NAN].is_sorted());
+    /// ```
+    #[inline]
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    pub fn is_sorted(&self) -> bool
+    where
+        T: PartialOrd,
+    {
+        self.is_sorted_by(|a, b| a.partial_cmp(b))
+    }
+
+    /// Checks if the elements of this slice are sorted using the given comparator function.
+    ///
+    /// Instead of using `PartialOrd::partial_cmp`, this function uses the given `compare`
+    /// function to determine the ordering of two elements. Apart from that, it's equivalent to
+    /// [`is_sorted`]; see its documentation for more information.
+    ///
+    /// [`is_sorted`]: #method.is_sorted
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    pub fn is_sorted_by<F>(&self, mut compare: F) -> bool
+    where
+        F: FnMut(&T, &T) -> Option<Ordering>
+    {
+        self.iter().is_sorted_by(|a, b| compare(*a, *b))
+    }
+
+    /// Checks if the elements of this slice are sorted using the given key extraction function.
+    ///
+    /// Instead of comparing the slice's elements directly, this function compares the keys of the
+    /// elements, as determined by `f`. Apart from that, it's equivalent to [`is_sorted`]; see its
+    /// documentation for more information.
+    ///
+    /// [`is_sorted`]: #method.is_sorted
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(is_sorted)]
+    ///
+    /// assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
+    /// assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
+    /// ```
+    #[inline]
+    #[unstable(feature = "is_sorted", reason = "new API", issue = "53485")]
+    pub fn is_sorted_by_key<F, K>(&self, mut f: F) -> bool
+    where
+        F: FnMut(&T) -> K,
+        K: PartialOrd
+    {
+        self.is_sorted_by(|a, b| f(a).partial_cmp(&f(b)))
+    }
 }
 
 #[lang = "slice_u8"]
@@ -2312,7 +2386,6 @@ impl [u8] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"]
 impl<T, I> ops::Index<I> for [T]
     where I: SliceIndex<[T]>
 {
@@ -2325,7 +2398,6 @@ impl<T, I> ops::Index<I> for [T]
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"]
 impl<T, I> ops::IndexMut<I> for [T]
     where I: SliceIndex<[T]>
 {
@@ -2376,7 +2448,19 @@ mod private_slice_index {
 
 /// A helper trait used for indexing operations.
 #[stable(feature = "slice_get_slice", since = "1.28.0")]
-#[rustc_on_unimplemented = "slice indices are of type `usize` or ranges of `usize`"]
+#[rustc_on_unimplemented(
+    on(
+        T = "str",
+        label = "string indices are ranges of `usize`",
+    ),
+    on(
+        all(any(T = "str", T = "&str", T = "std::string::String"), _Self="{integer}"),
+        note="you can use `.chars().nth()` or `.bytes().nth()`
+see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>"
+    ),
+    message = "the type `{T}` cannot be indexed by `{Self}`",
+    label = "slice indices are of type `usize` or ranges of `usize`",
+)]
 pub trait SliceIndex<T: ?Sized>: private_slice_index::Sealed {
     /// The output type returned by methods.
     #[stable(feature = "slice_get_slice", since = "1.28.0")]
@@ -2773,7 +2857,13 @@ macro_rules! len {
 
 // The shared definition of the `Iter` and `IterMut` iterators
 macro_rules! iterator {
-    (struct $name:ident -> $ptr:ty, $elem:ty, $raw_mut:tt, $( $mut_:tt )*) => {
+    (
+        struct $name:ident -> $ptr:ty,
+        $elem:ty,
+        $raw_mut:tt,
+        {$( $mut_:tt )*},
+        {$($extra:tt)*}
+    ) => {
         impl<'a, T> $name<'a, T> {
             // Helper function for creating a slice from the iterator.
             #[inline(always)]
@@ -2813,7 +2903,7 @@ macro_rules! iterator {
         }
 
         #[stable(feature = "rust1", since = "1.0.0")]
-        impl<'a, T> ExactSizeIterator for $name<'a, T> {
+        impl<T> ExactSizeIterator for $name<'_, T> {
             #[inline(always)]
             fn len(&self) -> usize {
                 len!(self)
@@ -2950,6 +3040,8 @@ macro_rules! iterator {
                         i
                     })
             }
+
+            $($extra)*
         }
 
         #[stable(feature = "rust1", since = "1.0.0")]
@@ -3006,10 +3098,10 @@ macro_rules! iterator {
         }
 
         #[stable(feature = "fused", since = "1.26.0")]
-        impl<'a, T> FusedIterator for $name<'a, T> {}
+        impl<T> FusedIterator for $name<'_, T> {}
 
         #[unstable(feature = "trusted_len", issue = "37572")]
-        unsafe impl<'a, T> TrustedLen for $name<'a, T> {}
+        unsafe impl<T> TrustedLen for $name<'_, T> {}
     }
 }
 
@@ -3057,7 +3149,7 @@ unsafe impl<T: Sync> Sync for Iter<'_, T> {}
 unsafe impl<T: Sync> Send for Iter<'_, T> {}
 
 impl<'a, T> Iter<'a, T> {
-    /// View the underlying data as a subslice of the original data.
+    /// Views the underlying data as a subslice of the original data.
     ///
     /// This has the same lifetime as the original slice, and so the
     /// iterator can continue to be used while this exists.
@@ -3087,7 +3179,17 @@ impl<'a, T> Iter<'a, T> {
     }
 }
 
-iterator!{struct Iter -> *const T, &'a T, const, /* no mut */}
+iterator!{struct Iter -> *const T, &'a T, const, {/* no mut */}, {
+    fn is_sorted_by<F>(self, mut compare: F) -> bool
+    where
+        Self: Sized,
+        F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
+    {
+        self.as_slice().windows(2).all(|w| {
+            compare(&&w[0], &&w[1]).map(|o| o != Ordering::Greater).unwrap_or(false)
+        })
+    }
+}}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> Clone for Iter<'_, T> {
@@ -3149,7 +3251,7 @@ unsafe impl<T: Sync> Sync for IterMut<'_, T> {}
 unsafe impl<T: Send> Send for IterMut<'_, T> {}
 
 impl<'a, T> IterMut<'a, T> {
-    /// View the underlying data as a subslice of the original data.
+    /// Views the underlying data as a subslice of the original data.
     ///
     /// To avoid creating `&mut` references that alias, this is forced
     /// to consume the iterator.
@@ -3188,7 +3290,7 @@ impl<'a, T> IterMut<'a, T> {
     }
 }
 
-iterator!{struct IterMut -> *mut T, &'a mut T, mut, mut}
+iterator!{struct IterMut -> *mut T, &'a mut T, mut, {mut}, {}}
 
 /// An internal abstraction over the splitting iterators, so that
 /// splitn, splitn_mut etc can be implemented once.
@@ -4025,7 +4127,7 @@ pub struct ChunksExact<'a, T:'a> {
 }
 
 impl<'a, T> ChunksExact<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "chunks_exact", since = "1.31.0")]
@@ -4149,7 +4251,7 @@ pub struct ChunksExactMut<'a, T:'a> {
 }
 
 impl<'a, T> ChunksExactMut<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "chunks_exact", since = "1.31.0")]
@@ -4263,8 +4365,8 @@ pub struct RChunks<'a, T:'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> Clone for RChunks<'a, T> {
-    fn clone(&self) -> RChunks<'a, T> {
+impl<T> Clone for RChunks<'_, T> {
+    fn clone(&self) -> Self {
         RChunks {
             v: self.v,
             chunk_size: self.chunk_size,
@@ -4353,13 +4455,13 @@ impl<'a, T> DoubleEndedIterator for RChunks<'a, T> {
 }
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> ExactSizeIterator for RChunks<'a, T> {}
+impl<T> ExactSizeIterator for RChunks<'_, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<'a, T> TrustedLen for RChunks<'a, T> {}
+unsafe impl<T> TrustedLen for RChunks<'_, T> {}
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> FusedIterator for RChunks<'a, T> {}
+impl<T> FusedIterator for RChunks<'_, T> {}
 
 #[doc(hidden)]
 #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4478,13 +4580,13 @@ impl<'a, T> DoubleEndedIterator for RChunksMut<'a, T> {
 }
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> ExactSizeIterator for RChunksMut<'a, T> {}
+impl<T> ExactSizeIterator for RChunksMut<'_, T> {}
 
 #[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<'a, T> TrustedLen for RChunksMut<'a, T> {}
+unsafe impl<T> TrustedLen for RChunksMut<'_, T> {}
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> FusedIterator for RChunksMut<'a, T> {}
+impl<T> FusedIterator for RChunksMut<'_, T> {}
 
 #[doc(hidden)]
 #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4521,7 +4623,7 @@ pub struct RChunksExact<'a, T:'a> {
 }
 
 impl<'a, T> RChunksExact<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4609,10 +4711,10 @@ impl<'a, T> ExactSizeIterator for RChunksExact<'a, T> {
 }
 
 #[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<'a, T> TrustedLen for RChunksExact<'a, T> {}
+unsafe impl<T> TrustedLen for RChunksExact<'_, T> {}
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> FusedIterator for RChunksExact<'a, T> {}
+impl<T> FusedIterator for RChunksExact<'_, T> {}
 
 #[doc(hidden)]
 #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4646,7 +4748,7 @@ pub struct RChunksExactMut<'a, T:'a> {
 }
 
 impl<'a, T> RChunksExactMut<'a, T> {
-    /// Return the remainder of the original slice that is not going to be
+    /// Returns the remainder of the original slice that is not going to be
     /// returned by the iterator. The returned slice has at most `chunk_size-1`
     /// elements.
     #[stable(feature = "rchunks", since = "1.31.0")]
@@ -4720,17 +4822,17 @@ impl<'a, T> DoubleEndedIterator for RChunksExactMut<'a, T> {
 }
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> ExactSizeIterator for RChunksExactMut<'a, T> {
+impl<T> ExactSizeIterator for RChunksExactMut<'_, T> {
     fn is_empty(&self) -> bool {
         self.v.is_empty()
     }
 }
 
 #[unstable(feature = "trusted_len", issue = "37572")]
-unsafe impl<'a, T> TrustedLen for RChunksExactMut<'a, T> {}
+unsafe impl<T> TrustedLen for RChunksExactMut<'_, T> {}
 
 #[stable(feature = "rchunks", since = "1.31.0")]
-impl<'a, T> FusedIterator for RChunksExactMut<'a, T> {}
+impl<T> FusedIterator for RChunksExactMut<'_, T> {}
 
 #[doc(hidden)]
 #[stable(feature = "rchunks", since = "1.31.0")]
diff --git a/src/libcore/slice/rotate.rs b/src/libcore/slice/rotate.rs
index 52677713f5ac4..9b35b51349a02 100644
--- a/src/libcore/slice/rotate.rs
+++ b/src/libcore/slice/rotate.rs
@@ -26,7 +26,7 @@ impl<T> RawArray<T> {
 }
 
 /// Rotates the range `[mid-left, mid+right)` such that the element at `mid`
-/// becomes the first element.  Equivalently, rotates the range `left`
+/// becomes the first element. Equivalently, rotates the range `left`
 /// elements to the left or `right` elements to the right.
 ///
 /// # Safety
@@ -36,10 +36,10 @@ impl<T> RawArray<T> {
 /// # Algorithm
 ///
 /// For longer rotations, swap the left-most `delta = min(left, right)`
-/// elements with the right-most `delta` elements.  LLVM vectorizes this,
+/// elements with the right-most `delta` elements. LLVM vectorizes this,
 /// which is profitable as we only reach this step for a "large enough"
-/// rotation.  Doing this puts `delta` elements on the larger side into the
-/// correct position, leaving a smaller rotate problem.  Demonstration:
+/// rotation. Doing this puts `delta` elements on the larger side into the
+/// correct position, leaving a smaller rotate problem. Demonstration:
 ///
 /// ```text
 /// [ 6 7 8 9 10 11 12 13 . 1 2 3 4 5 ]
diff --git a/src/libcore/slice/sort.rs b/src/libcore/slice/sort.rs
index dd9b49fb7a002..3f84faa049939 100644
--- a/src/libcore/slice/sort.rs
+++ b/src/libcore/slice/sort.rs
@@ -216,14 +216,14 @@ fn partition_in_blocks<T, F>(v: &mut [T], pivot: &T, is_less: &mut F) -> usize
     let mut block_l = BLOCK;
     let mut start_l = ptr::null_mut();
     let mut end_l = ptr::null_mut();
-    let mut offsets_l = MaybeUninit::<[u8; BLOCK]>::uninitialized();
+    let mut offsets_l: [MaybeUninit<u8>; BLOCK] = uninitialized_array![u8; BLOCK];
 
     // The current block on the right side (from `r.sub(block_r)` to `r`).
     let mut r = unsafe { l.add(v.len()) };
     let mut block_r = BLOCK;
     let mut start_r = ptr::null_mut();
     let mut end_r = ptr::null_mut();
-    let mut offsets_r = MaybeUninit::<[u8; BLOCK]>::uninitialized();
+    let mut offsets_r: [MaybeUninit<u8>; BLOCK] = uninitialized_array![u8; BLOCK];
 
     // FIXME: When we get VLAs, try creating one array of length `min(v.len(), 2 * BLOCK)` rather
     // than two fixed-size arrays of length `BLOCK`. VLAs might be more cache-efficient.
@@ -262,8 +262,8 @@ fn partition_in_blocks<T, F>(v: &mut [T], pivot: &T, is_less: &mut F) -> usize
 
         if start_l == end_l {
             // Trace `block_l` elements from the left side.
-            start_l = offsets_l.as_mut_ptr() as *mut u8;
-            end_l = offsets_l.as_mut_ptr() as *mut u8;
+            start_l = MaybeUninit::first_ptr_mut(&mut offsets_l);
+            end_l = MaybeUninit::first_ptr_mut(&mut offsets_l);
             let mut elem = l;
 
             for i in 0..block_l {
@@ -278,8 +278,8 @@ fn partition_in_blocks<T, F>(v: &mut [T], pivot: &T, is_less: &mut F) -> usize
 
         if start_r == end_r {
             // Trace `block_r` elements from the right side.
-            start_r = offsets_r.as_mut_ptr() as *mut u8;
-            end_r = offsets_r.as_mut_ptr() as *mut u8;
+            start_r = MaybeUninit::first_ptr_mut(&mut offsets_r);
+            end_r = MaybeUninit::first_ptr_mut(&mut offsets_r);
             let mut elem = r;
 
             for i in 0..block_r {
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index bdde187d931cc..8b51d8465141a 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -1,6 +1,6 @@
-//! String manipulation
+//! String manipulation.
 //!
-//! For more details, see std::str
+//! For more details, see the `std::str` module.
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
@@ -8,11 +8,13 @@ use self::pattern::Pattern;
 use self::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
 
 use char;
-use fmt;
-use iter::{Map, Cloned, FusedIterator, TrustedLen, Filter};
-use iter_private::TrustedRandomAccess;
+use fmt::{self, Write};
+use iter::{Map, Cloned, FusedIterator, TrustedLen, TrustedRandomAccess, Filter};
+use iter::{Flatten, FlatMap, Chain};
 use slice::{self, SliceIndex, Split as SliceSplit};
 use mem;
+use ops::Try;
+use option;
 
 pub mod pattern;
 
@@ -227,7 +229,7 @@ impl Utf8Error {
     #[stable(feature = "utf8_error", since = "1.5.0")]
     pub fn valid_up_to(&self) -> usize { self.valid_up_to }
 
-    /// Provide more information about the failure:
+    /// Provides more information about the failure:
     ///
     /// * `None`: the end of the input was reached unexpectedly.
     ///   `self.valid_up_to()` is 1 to 3 bytes from the end of the input.
@@ -613,7 +615,7 @@ impl<'a> DoubleEndedIterator for Chars<'a> {
 impl FusedIterator for Chars<'_> {}
 
 impl<'a> Chars<'a> {
-    /// View the underlying data as a subslice of the original data.
+    /// Views the underlying data as a subslice of the original data.
     ///
     /// This has the same lifetime as the original slice, and so the
     /// iterator can continue to be used while this exists.
@@ -703,7 +705,7 @@ impl<'a> DoubleEndedIterator for CharIndices<'a> {
 impl FusedIterator for CharIndices<'_> {}
 
 impl<'a> CharIndices<'a> {
-    /// View the underlying data as a subslice of the original data.
+    /// Views the underlying data as a subslice of the original data.
     ///
     /// This has the same lifetime as the original slice, and so the
     /// iterator can continue to be used while this exists.
@@ -821,7 +823,7 @@ impl FusedIterator for Bytes<'_> {}
 unsafe impl TrustedLen for Bytes<'_> {}
 
 #[doc(hidden)]
-unsafe impl<'a> TrustedRandomAccess for Bytes<'a> {
+unsafe impl TrustedRandomAccess for Bytes<'_> {
     unsafe fn get_unchecked(&mut self, i: usize) -> u8 {
         self.0.get_unchecked(i)
     }
@@ -1346,33 +1348,14 @@ impl FusedIterator for Lines<'_> {}
 #[allow(deprecated)]
 pub struct LinesAny<'a>(Lines<'a>);
 
-/// A nameable, cloneable fn type
-#[derive(Clone)]
-struct LinesAnyMap;
-
-impl<'a> Fn<(&'a str,)> for LinesAnyMap {
-    #[inline]
-    extern "rust-call" fn call(&self, (line,): (&'a str,)) -> &'a str {
+impl_fn_for_zst! {
+    /// A nameable, cloneable fn type
+    #[derive(Clone)]
+    struct LinesAnyMap impl<'a> Fn = |line: &'a str| -> &'a str {
         let l = line.len();
         if l > 0 && line.as_bytes()[l - 1] == b'\r' { &line[0 .. l - 1] }
         else { line }
-    }
-}
-
-impl<'a> FnMut<(&'a str,)> for LinesAnyMap {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, (line,): (&'a str,)) -> &'a str {
-        Fn::call(&*self, (line,))
-    }
-}
-
-impl<'a> FnOnce<(&'a str,)> for LinesAnyMap {
-    type Output = &'a str;
-
-    #[inline]
-    extern "rust-call" fn call_once(self, (line,): (&'a str,)) -> &'a str {
-        Fn::call(&self, (line,))
-    }
+    };
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1580,9 +1563,9 @@ mod traits {
 
     /// Implements ordering of strings.
     ///
-    /// Strings are ordered  lexicographically by their byte values.  This orders Unicode code
-    /// points based on their positions in the code charts.  This is not necessarily the same as
-    /// "alphabetical" order, which varies by language and locale.  Sorting strings according to
+    /// Strings are ordered  lexicographically by their byte values. This orders Unicode code
+    /// points based on their positions in the code charts. This is not necessarily the same as
+    /// "alphabetical" order, which varies by language and locale. Sorting strings according to
     /// culturally-accepted standards requires locale-specific data that is outside the scope of
     /// the `str` type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -1608,9 +1591,9 @@ mod traits {
 
     /// Implements comparison operations on strings.
     ///
-    /// Strings are compared lexicographically by their byte values.  This compares Unicode code
-    /// points based on their positions in the code charts.  This is not necessarily the same as
-    /// "alphabetical" order, which varies by language and locale.  Comparing strings according to
+    /// Strings are compared lexicographically by their byte values. This compares Unicode code
+    /// points based on their positions in the code charts. This is not necessarily the same as
+    /// "alphabetical" order, which varies by language and locale. Comparing strings according to
     /// culturally-accepted standards requires locale-specific data that is outside the scope of
     /// the `str` type.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -1621,190 +1604,26 @@ mod traits {
         }
     }
 
-    /// Implements substring slicing with syntax `&self[begin .. end]`.
-    ///
-    /// Returns a slice of the given string from the byte range
-    /// [`begin`..`end`).
-    ///
-    /// This operation is `O(1)`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if `begin` or `end` does not point to the starting
-    /// byte offset of a character (as defined by `is_char_boundary`).
-    /// Requires that `begin <= end` and `end <= len` where `len` is the
-    /// length of the string.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let s = "Löwe 老虎 Léopard";
-    /// assert_eq!(&s[0 .. 1], "L");
-    ///
-    /// assert_eq!(&s[1 .. 9], "öwe 老");
-    ///
-    /// // these will panic:
-    /// // byte 2 lies within `ö`:
-    /// // &s[2 ..3];
-    ///
-    /// // byte 8 lies within `老`
-    /// // &s[1 .. 8];
-    ///
-    /// // byte 100 is outside the string
-    /// // &s[3 .. 100];
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    impl ops::Index<ops::Range<usize>> for str {
-        type Output = str;
-        #[inline]
-        fn index(&self, index: ops::Range<usize>) -> &str {
-            index.index(self)
-        }
-    }
-
-    /// Implements mutable substring slicing with syntax
-    /// `&mut self[begin .. end]`.
-    ///
-    /// Returns a mutable slice of the given string from the byte range
-    /// [`begin`..`end`).
-    ///
-    /// This operation is `O(1)`.
-    ///
-    /// # Panics
-    ///
-    /// Panics if `begin` or `end` does not point to the starting
-    /// byte offset of a character (as defined by `is_char_boundary`).
-    /// Requires that `begin <= end` and `end <= len` where `len` is the
-    /// length of the string.
-    #[stable(feature = "derefmut_for_string", since = "1.3.0")]
-    impl ops::IndexMut<ops::Range<usize>> for str {
-        #[inline]
-        fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
-            index.index_mut(self)
-        }
-    }
-
-    /// Implements substring slicing with syntax `&self[.. end]`.
-    ///
-    /// Returns a slice of the string from the beginning to byte offset
-    /// `end`.
-    ///
-    /// Equivalent to `&self[0 .. end]`.
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl ops::Index<ops::RangeTo<usize>> for str {
-        type Output = str;
-
-        #[inline]
-        fn index(&self, index: ops::RangeTo<usize>) -> &str {
-            index.index(self)
-        }
-    }
-
-    /// Implements mutable substring slicing with syntax `&mut self[.. end]`.
-    ///
-    /// Returns a mutable slice of the string from the beginning to byte offset
-    /// `end`.
-    ///
-    /// Equivalent to `&mut self[0 .. end]`.
-    #[stable(feature = "derefmut_for_string", since = "1.3.0")]
-    impl ops::IndexMut<ops::RangeTo<usize>> for str {
-        #[inline]
-        fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
-            index.index_mut(self)
-        }
-    }
-
-    /// Implements substring slicing with syntax `&self[begin ..]`.
-    ///
-    /// Returns a slice of the string from byte offset `begin`
-    /// to the end of the string.
-    ///
-    /// Equivalent to `&self[begin .. len]`.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    impl ops::Index<ops::RangeFrom<usize>> for str {
-        type Output = str;
+    impl<I> ops::Index<I> for str
+    where
+        I: SliceIndex<str>,
+    {
+        type Output = I::Output;
 
         #[inline]
-        fn index(&self, index: ops::RangeFrom<usize>) -> &str {
+        fn index(&self, index: I) -> &I::Output {
             index.index(self)
         }
     }
 
-    /// Implements mutable substring slicing with syntax `&mut self[begin ..]`.
-    ///
-    /// Returns a mutable slice of the string from byte offset `begin`
-    /// to the end of the string.
-    ///
-    /// Equivalent to `&mut self[begin .. len]`.
-    #[stable(feature = "derefmut_for_string", since = "1.3.0")]
-    impl ops::IndexMut<ops::RangeFrom<usize>> for str {
-        #[inline]
-        fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
-            index.index_mut(self)
-        }
-    }
-
-    /// Implements substring slicing with syntax `&self[..]`.
-    ///
-    /// Returns a slice of the whole string. This operation can
-    /// never panic.
-    ///
-    /// Equivalent to `&self[0 .. len]`.
     #[stable(feature = "rust1", since = "1.0.0")]
-    impl ops::Index<ops::RangeFull> for str {
-        type Output = str;
-
-        #[inline]
-        fn index(&self, _index: ops::RangeFull) -> &str {
-            self
-        }
-    }
-
-    /// Implements mutable substring slicing with syntax `&mut self[..]`.
-    ///
-    /// Returns a mutable slice of the whole string. This operation can
-    /// never panic.
-    ///
-    /// Equivalent to `&mut self[0 .. len]`.
-    #[stable(feature = "derefmut_for_string", since = "1.3.0")]
-    impl ops::IndexMut<ops::RangeFull> for str {
-        #[inline]
-        fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
-            self
-        }
-    }
-
-    #[stable(feature = "inclusive_range", since = "1.26.0")]
-    impl ops::Index<ops::RangeInclusive<usize>> for str {
-        type Output = str;
-
-        #[inline]
-        fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
-            index.index(self)
-        }
-    }
-
-    #[stable(feature = "inclusive_range", since = "1.26.0")]
-    impl ops::Index<ops::RangeToInclusive<usize>> for str {
-        type Output = str;
-
-        #[inline]
-        fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
-            index.index(self)
-        }
-    }
-
-    #[stable(feature = "inclusive_range", since = "1.26.0")]
-    impl ops::IndexMut<ops::RangeInclusive<usize>> for str {
-        #[inline]
-        fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
-            index.index_mut(self)
-        }
-    }
-    #[stable(feature = "inclusive_range", since = "1.26.0")]
-    impl ops::IndexMut<ops::RangeToInclusive<usize>> for str {
+    impl<I> ops::IndexMut<I> for str
+    where
+        I: SliceIndex<str>,
+    {
         #[inline]
-        fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
+        fn index_mut(&mut self, index: I) -> &mut I::Output {
             index.index_mut(self)
         }
     }
@@ -1815,6 +1634,18 @@ mod traits {
         panic!("attempted to index str up to maximum usize");
     }
 
+    /// Implements substring slicing with syntax `&self[..]` or `&mut self[..]`.
+    ///
+    /// Returns a slice of the whole string, i.e., returns `&self` or `&mut
+    /// self`. Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`. Unlike
+    /// other indexing operations, this can never panic.
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// Prior to 1.20.0, these indexing operations were still supported by
+    /// direct implementation of `Index` and `IndexMut`.
+    ///
+    /// Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`.
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
     impl SliceIndex<str> for ops::RangeFull {
         type Output = str;
@@ -1844,6 +1675,41 @@ mod traits {
         }
     }
 
+    /// Implements substring slicing with syntax `&self[begin .. end]` or `&mut
+    /// self[begin .. end]`.
+    ///
+    /// Returns a slice of the given string from the byte range
+    /// [`begin`, `end`).
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// Prior to 1.20.0, these indexing operations were still supported by
+    /// direct implementation of `Index` and `IndexMut`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `begin` or `end` does not point to the starting byte offset of
+    /// a character (as defined by `is_char_boundary`), if `begin > end`, or if
+    /// `end > len`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = "Löwe 老虎 Léopard";
+    /// assert_eq!(&s[0 .. 1], "L");
+    ///
+    /// assert_eq!(&s[1 .. 9], "öwe 老");
+    ///
+    /// // these will panic:
+    /// // byte 2 lies within `ö`:
+    /// // &s[2 ..3];
+    ///
+    /// // byte 8 lies within `老`
+    /// // &s[1 .. 8];
+    ///
+    /// // byte 100 is outside the string
+    /// // &s[3 .. 100];
+    /// ```
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
     impl SliceIndex<str> for ops::Range<usize> {
         type Output = str;
@@ -1875,9 +1741,9 @@ mod traits {
         }
         #[inline]
         unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
-            let ptr = slice.as_ptr().add(self.start);
+            let ptr = slice.as_mut_ptr().add(self.start);
             let len = self.end - self.start;
-            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, len))
+            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
         }
         #[inline]
         fn index(self, slice: &str) -> &Self::Output {
@@ -1898,6 +1764,21 @@ mod traits {
         }
     }
 
+    /// Implements substring slicing with syntax `&self[.. end]` or `&mut
+    /// self[.. end]`.
+    ///
+    /// Returns a slice of the given string from the byte range [`0`, `end`).
+    /// Equivalent to `&self[0 .. end]` or `&mut self[0 .. end]`.
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// Prior to 1.20.0, these indexing operations were still supported by
+    /// direct implementation of `Index` and `IndexMut`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `end` does not point to the starting byte offset of a
+    /// character (as defined by `is_char_boundary`), or if `end > len`.
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
     impl SliceIndex<str> for ops::RangeTo<usize> {
         type Output = str;
@@ -1924,8 +1805,8 @@ mod traits {
         }
         #[inline]
         unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
-            let ptr = slice.as_ptr();
-            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, self.end))
+            let ptr = slice.as_mut_ptr();
+            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, self.end))
         }
         #[inline]
         fn index(self, slice: &str) -> &Self::Output {
@@ -1943,6 +1824,22 @@ mod traits {
         }
     }
 
+    /// Implements substring slicing with syntax `&self[begin ..]` or `&mut
+    /// self[begin ..]`.
+    ///
+    /// Returns a slice of the given string from the byte range [`begin`,
+    /// `len`). Equivalent to `&self[begin .. len]` or `&mut self[begin ..
+    /// len]`.
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// Prior to 1.20.0, these indexing operations were still supported by
+    /// direct implementation of `Index` and `IndexMut`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `begin` does not point to the starting byte offset of
+    /// a character (as defined by `is_char_boundary`), or if `begin >= len`.
     #[stable(feature = "str_checked_slicing", since = "1.20.0")]
     impl SliceIndex<str> for ops::RangeFrom<usize> {
         type Output = str;
@@ -1970,9 +1867,9 @@ mod traits {
         }
         #[inline]
         unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
-            let ptr = slice.as_ptr().add(self.start);
+            let ptr = slice.as_mut_ptr().add(self.start);
             let len = slice.len() - self.start;
-            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, len))
+            super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
         }
         #[inline]
         fn index(self, slice: &str) -> &Self::Output {
@@ -1990,6 +1887,22 @@ mod traits {
         }
     }
 
+    /// Implements substring slicing with syntax `&self[begin ..= end]` or `&mut
+    /// self[begin ..= end]`.
+    ///
+    /// Returns a slice of the given string from the byte range
+    /// [`begin`, `end`]. Equivalent to `&self [begin .. end + 1]` or `&mut
+    /// self[begin .. end + 1]`, except if `end` has the maximum value for
+    /// `usize`.
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `begin` does not point to the starting byte offset of
+    /// a character (as defined by `is_char_boundary`), if `end` does not point
+    /// to the ending byte offset of a character (`end + 1` is either a starting
+    /// byte offset or equal to `len`), if `begin > end`, or if `end >= len`.
     #[stable(feature = "inclusive_range", since = "1.26.0")]
     impl SliceIndex<str> for ops::RangeInclusive<usize> {
         type Output = str;
@@ -2023,8 +1936,20 @@ mod traits {
         }
     }
 
-
-
+    /// Implements substring slicing with syntax `&self[..= end]` or `&mut
+    /// self[..= end]`.
+    ///
+    /// Returns a slice of the given string from the byte range [0, `end`].
+    /// Equivalent to `&self [0 .. end + 1]`, except if `end` has the maximum
+    /// value for `usize`.
+    ///
+    /// This operation is `O(1)`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `end` does not point to the ending byte offset of a character
+    /// (`end + 1` is either a starting byte offset as defined by
+    /// `is_char_boundary`, or equal to `len`), or if `end >= len`.
     #[stable(feature = "inclusive_range", since = "1.26.0")]
     impl SliceIndex<str> for ops::RangeToInclusive<usize> {
         type Output = str;
@@ -2272,6 +2197,22 @@ impl str {
         self as *const str as *const u8
     }
 
+    /// Converts a mutable string slice to a raw pointer.
+    ///
+    /// As string slices are a slice of bytes, the raw pointer points to a
+    /// [`u8`]. This pointer will be pointing to the first byte of the string
+    /// slice.
+    ///
+    /// It is your responsibility to make sure that the string slice only gets
+    /// modified in a way that it remains valid UTF-8.
+    ///
+    /// [`u8`]: primitive.u8.html
+    #[unstable(feature = "str_as_mut_ptr", issue = "58215")]
+    #[inline]
+    pub fn as_mut_ptr(&mut self) -> *mut u8 {
+        self as *mut str as *mut u8
+    }
+
     /// Returns a subslice of `str`.
     ///
     /// This is the non-panicking alternative to indexing the `str`. Returns
@@ -2559,7 +2500,7 @@ impl str {
         // is_char_boundary checks that the index is in [0, .len()]
         if self.is_char_boundary(mid) {
             let len = self.len();
-            let ptr = self.as_ptr() as *mut u8;
+            let ptr = self.as_mut_ptr();
             unsafe {
                 (from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, mid)),
                  from_utf8_unchecked_mut(slice::from_raw_parts_mut(
@@ -2702,7 +2643,7 @@ impl str {
         Bytes(self.as_bytes().iter().cloned())
     }
 
-    /// Split a string slice by whitespace.
+    /// Splits a string slice by whitespace.
     ///
     /// The iterator returned will return string slices that are sub-slices of
     /// the original string slice, separated by any amount of whitespace.
@@ -2745,7 +2686,7 @@ impl str {
         SplitWhitespace { inner: self.split(IsWhitespace).filter(IsNotEmpty) }
     }
 
-    /// Split a string slice by ASCII whitespace.
+    /// Splits a string slice by ASCII whitespace.
     ///
     /// The iterator returned will return string slices that are sub-slices of
     /// the original string slice, separated by any amount of ASCII whitespace.
@@ -2759,7 +2700,6 @@ impl str {
     /// Basic usage:
     ///
     /// ```
-    /// #![feature(split_ascii_whitespace)]
     /// let mut iter = "A few words".split_ascii_whitespace();
     ///
     /// assert_eq!(Some("A"), iter.next());
@@ -2781,13 +2721,13 @@ impl str {
     ///
     /// assert_eq!(None, iter.next());
     /// ```
-    #[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+    #[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
     #[inline]
     pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace {
         let inner = self
             .as_bytes()
             .split(IsAsciiWhitespace)
-            .filter(IsNotEmpty)
+            .filter(BytesIsNotEmpty)
             .map(UnsafeBytesToStr);
         SplitAsciiWhitespace { inner }
     }
@@ -3021,8 +2961,8 @@ impl str {
     /// An iterator over substrings of this string slice, separated by
     /// characters matched by a pattern.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines the
-    /// split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// # Iterator behavior
     ///
@@ -3138,8 +3078,8 @@ impl str {
     /// An iterator over substrings of the given string slice, separated by
     /// characters matched by a pattern and yielded in reverse order.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines the
-    /// split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// # Iterator behavior
     ///
@@ -3188,8 +3128,8 @@ impl str {
     /// An iterator over substrings of the given string slice, separated by
     /// characters matched by a pattern.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines the
-    /// split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// Equivalent to [`split`], except that the trailing substring
     /// is skipped if empty.
@@ -3235,8 +3175,8 @@ impl str {
     /// An iterator over substrings of `self`, separated by characters
     /// matched by a pattern and yielded in reverse order.
     ///
-    /// The pattern can be a simple `&str`, [`char`], or a closure that
-    /// determines the split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     /// Additional libraries might provide more complex patterns like
     /// regular expressions.
     ///
@@ -3282,8 +3222,8 @@ impl str {
     /// If `n` substrings are returned, the last substring (the `n`th substring)
     /// will contain the remainder of the string.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that determines the
-    /// split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// # Iterator behavior
     ///
@@ -3335,8 +3275,8 @@ impl str {
     /// If `n` substrings are returned, the last substring (the `n`th substring)
     /// will contain the remainder of the string.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that
-    /// determines the split.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// # Iterator behavior
     ///
@@ -3379,8 +3319,8 @@ impl str {
     /// An iterator over the disjoint matches of a pattern within the given string
     /// slice.
     ///
-    /// The pattern can be a `&str`, [`char`], or a closure that
-    /// determines if a character matches.
+    /// The pattern can be any type that implements the Pattern trait. Notable
+    /// examples are `&str`, [`char`], and closures that determines the split.
     ///
     /// # Iterator behavior
     ///
@@ -3548,6 +3488,8 @@ impl str {
     ///
     /// assert_eq!("Hello\tworld", s.trim());
     /// ```
+    #[must_use = "this returns the trimmed string as a slice, \
+                  without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn trim(&self) -> &str {
         self.trim_matches(|c: char| c.is_whitespace())
@@ -3562,7 +3504,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `start` in this context means the first
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be left side; and for right-to-left languages like
+    /// Russian, this will be left side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
@@ -3583,6 +3525,8 @@ impl str {
     /// let s = "  עברית  ";
     /// assert!(Some('ע') == s.trim_start().chars().next());
     /// ```
+    #[must_use = "this returns the trimmed string as a new slice, \
+                  without modifying the original"]
     #[stable(feature = "trim_direction", since = "1.30.0")]
     pub fn trim_start(&self) -> &str {
         self.trim_start_matches(|c: char| c.is_whitespace())
@@ -3597,7 +3541,7 @@ impl str {
     ///
     /// A string is a sequence of bytes. `end` in this context means the last
     /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be right side; and for right-to-left languages like
+    /// Russian, this will be right side, and for right-to-left languages like
     /// like Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
@@ -3618,6 +3562,8 @@ impl str {
     /// let s = "  עברית  ";
     /// assert!(Some('ת') == s.trim_end().chars().rev().next());
     /// ```
+    #[must_use = "this returns the trimmed string as a new slice, \
+                  without modifying the original"]
     #[stable(feature = "trim_direction", since = "1.30.0")]
     pub fn trim_end(&self) -> &str {
         self.trim_end_matches(|c: char| c.is_whitespace())
@@ -3720,6 +3666,8 @@ impl str {
     /// ```
     /// assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");
     /// ```
+    #[must_use = "this returns the trimmed string as a new slice, \
+                  without modifying the original"]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
         where P::Searcher: DoubleEndedSearcher<'a>
@@ -3765,6 +3713,8 @@ impl str {
     /// let x: &[_] = &['1', '2'];
     /// assert_eq!("12foo1bar12".trim_start_matches(x), "foo1bar12");
     /// ```
+    #[must_use = "this returns the trimmed string as a new slice, \
+                  without modifying the original"]
     #[stable(feature = "trim_direction", since = "1.30.0")]
     pub fn trim_start_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str {
         let mut i = self.len();
@@ -3808,6 +3758,8 @@ impl str {
     /// ```
     /// assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");
     /// ```
+    #[must_use = "this returns the trimmed string as a new slice, \
+                  without modifying the original"]
     #[stable(feature = "trim_direction", since = "1.30.0")]
     pub fn trim_end_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
         where P::Searcher: ReverseSearcher<'a>
@@ -3833,10 +3785,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. 'Left' in this context means the first
-    /// position of that byte string; for a language like Arabic or Hebrew
-    /// which are 'right to left' rather than 'left to right', this will be
-    /// the _right_ side, not the left.
+    /// A string is a sequence of bytes. `start` in this context means the first
+    /// position of that byte string; for a left-to-right language like English or
+    /// Russian, this will be left side, and for right-to-left languages like
+    /// like Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
     ///
@@ -3865,10 +3817,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. 'Right' in this context means the last
-    /// position of that byte string; for a language like Arabic or Hebrew
-    /// which are 'right to left' rather than 'left to right', this will be
-    /// the _left_ side, not the right.
+    /// A string is a sequence of bytes. `end` in this context means the last
+    /// position of that byte string; for a left-to-right language like English or
+    /// Russian, this will be right side, and for right-to-left languages like
+    /// like Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
     ///
@@ -4012,6 +3964,146 @@ impl str {
         let me = unsafe { self.as_bytes_mut() };
         me.make_ascii_lowercase()
     }
+
+    /// Return an iterator that escapes each char in `s` with [`char::escape_debug`].
+    ///
+    /// Note: only extended grapheme codepoints that begin the string will be
+    /// escaped.
+    ///
+    /// [`char::escape_debug`]: ../std/primitive.char.html#method.escape_debug
+    ///
+    /// # Examples
+    ///
+    /// As an iterator:
+    ///
+    /// ```
+    /// for c in "❤\n!".escape_debug() {
+    ///     print!("{}", c);
+    /// }
+    /// println!();
+    /// ```
+    ///
+    /// Using `println!` directly:
+    ///
+    /// ```
+    /// println!("{}", "❤\n!".escape_debug());
+    /// ```
+    ///
+    ///
+    /// Both are equivalent to:
+    ///
+    /// ```
+    /// println!("❤\\n!");
+    /// ```
+    ///
+    /// Using `to_string`:
+    ///
+    /// ```
+    /// assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");
+    /// ```
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_debug(&self) -> EscapeDebug {
+        let mut chars = self.chars();
+        EscapeDebug {
+            inner: chars.next()
+                .map(|first| first.escape_debug_ext(true))
+                .into_iter()
+                .flatten()
+                .chain(chars.flat_map(CharEscapeDebugContinue))
+        }
+    }
+
+    /// Return an iterator that escapes each char in `s` with [`char::escape_default`].
+    ///
+    /// [`char::escape_default`]: ../std/primitive.char.html#method.escape_default
+    ///
+    /// # Examples
+    ///
+    /// As an iterator:
+    ///
+    /// ```
+    /// for c in "❤\n!".escape_default() {
+    ///     print!("{}", c);
+    /// }
+    /// println!();
+    /// ```
+    ///
+    /// Using `println!` directly:
+    ///
+    /// ```
+    /// println!("{}", "❤\n!".escape_default());
+    /// ```
+    ///
+    ///
+    /// Both are equivalent to:
+    ///
+    /// ```
+    /// println!("\\u{{2764}}\n!");
+    /// ```
+    ///
+    /// Using `to_string`:
+    ///
+    /// ```
+    /// assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");
+    /// ```
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_default(&self) -> EscapeDefault {
+        EscapeDefault { inner: self.chars().flat_map(CharEscapeDefault) }
+    }
+
+    /// Return an iterator that escapes each char in `s` with [`char::escape_unicode`].
+    ///
+    /// [`char::escape_unicode`]: ../std/primitive.char.html#method.escape_unicode
+    ///
+    /// # Examples
+    ///
+    /// As an iterator:
+    ///
+    /// ```
+    /// for c in "❤\n!".escape_unicode() {
+    ///     print!("{}", c);
+    /// }
+    /// println!();
+    /// ```
+    ///
+    /// Using `println!` directly:
+    ///
+    /// ```
+    /// println!("{}", "❤\n!".escape_unicode());
+    /// ```
+    ///
+    ///
+    /// Both are equivalent to:
+    ///
+    /// ```
+    /// println!("\\u{{2764}}\\u{{a}}\\u{{21}}");
+    /// ```
+    ///
+    /// Using `to_string`:
+    ///
+    /// ```
+    /// assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");
+    /// ```
+    #[stable(feature = "str_escape", since = "1.34.0")]
+    pub fn escape_unicode(&self) -> EscapeUnicode {
+        EscapeUnicode { inner: self.chars().flat_map(CharEscapeUnicode) }
+    }
+}
+
+impl_fn_for_zst! {
+    #[derive(Clone)]
+    struct CharEscapeDebugContinue impl Fn = |c: char| -> char::EscapeDebug {
+        c.escape_debug_ext(false)
+    };
+
+    #[derive(Clone)]
+    struct CharEscapeUnicode impl Fn = |c: char| -> char::EscapeUnicode {
+        c.escape_unicode()
+    };
+    #[derive(Clone)]
+    struct CharEscapeDefault impl Fn = |c: char| -> char::EscapeDefault {
+        c.escape_default()
+    };
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -4056,105 +4148,39 @@ pub struct SplitWhitespace<'a> {
 ///
 /// [`split_ascii_whitespace`]: ../../std/primitive.str.html#method.split_ascii_whitespace
 /// [`str`]: ../../std/primitive.str.html
-#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
 #[derive(Clone, Debug)]
 pub struct SplitAsciiWhitespace<'a> {
-    inner: Map<Filter<SliceSplit<'a, u8, IsAsciiWhitespace>, IsNotEmpty>, UnsafeBytesToStr>,
-}
-
-#[derive(Clone)]
-struct IsWhitespace;
-
-impl FnOnce<(char, )> for IsWhitespace {
-    type Output = bool;
-
-    #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (char, )) -> bool {
-        self.call_mut(arg)
-    }
-}
-
-impl FnMut<(char, )> for IsWhitespace {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (char, )) -> bool {
-        arg.0.is_whitespace()
-    }
-}
-
-#[derive(Clone)]
-struct IsAsciiWhitespace;
-
-impl<'a> FnOnce<(&'a u8, )> for IsAsciiWhitespace {
-    type Output = bool;
-
-    #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (&u8, )) -> bool {
-        self.call_mut(arg)
-    }
-}
-
-impl<'a> FnMut<(&'a u8, )> for IsAsciiWhitespace {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (&u8, )) -> bool {
-        arg.0.is_ascii_whitespace()
-    }
-}
-
-#[derive(Clone)]
-struct IsNotEmpty;
-
-impl<'a, 'b> FnOnce<(&'a &'b str, )> for IsNotEmpty {
-    type Output = bool;
-
-    #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (&'a &'b str, )) -> bool {
-        self.call_mut(arg)
-    }
-}
-
-impl<'a, 'b> FnMut<(&'a &'b str, )> for IsNotEmpty {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (&'a &'b str, )) -> bool {
-        !arg.0.is_empty()
-    }
-}
-
-impl<'a, 'b> FnOnce<(&'a &'b [u8], )> for IsNotEmpty {
-    type Output = bool;
-
-    #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (&'a &'b [u8], )) -> bool {
-        self.call_mut(arg)
-    }
+    inner: Map<Filter<SliceSplit<'a, u8, IsAsciiWhitespace>, BytesIsNotEmpty>, UnsafeBytesToStr>,
 }
 
-impl<'a, 'b> FnMut<(&'a &'b [u8], )> for IsNotEmpty {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (&'a &'b [u8], )) -> bool {
-        !arg.0.is_empty()
-    }
-}
+impl_fn_for_zst! {
+    #[derive(Clone)]
+    struct IsWhitespace impl Fn = |c: char| -> bool {
+        c.is_whitespace()
+    };
 
-#[derive(Clone)]
-struct UnsafeBytesToStr;
+    #[derive(Clone)]
+    struct IsAsciiWhitespace impl Fn = |byte: &u8| -> bool {
+        byte.is_ascii_whitespace()
+    };
 
-impl<'a> FnOnce<(&'a [u8], )> for UnsafeBytesToStr {
-    type Output = &'a str;
+    #[derive(Clone)]
+    struct IsNotEmpty impl<'a, 'b> Fn = |s: &'a &'b str| -> bool {
+        !s.is_empty()
+    };
 
-    #[inline]
-    extern "rust-call" fn call_once(mut self, arg: (&'a [u8], )) -> &'a str {
-        self.call_mut(arg)
-    }
-}
+    #[derive(Clone)]
+    struct BytesIsNotEmpty impl<'a, 'b> Fn = |s: &'a &'b [u8]| -> bool {
+        !s.is_empty()
+    };
 
-impl<'a> FnMut<(&'a [u8], )> for UnsafeBytesToStr {
-    #[inline]
-    extern "rust-call" fn call_mut(&mut self, arg: (&'a [u8], )) -> &'a str {
-        unsafe { from_utf8_unchecked(arg.0) }
-    }
+    #[derive(Clone)]
+    struct UnsafeBytesToStr impl<'a> Fn = |bytes: &'a [u8]| -> &'a str {
+        unsafe { from_utf8_unchecked(bytes) }
+    };
 }
 
-
 #[stable(feature = "split_whitespace", since = "1.1.0")]
 impl<'a> Iterator for SplitWhitespace<'a> {
     type Item = &'a str;
@@ -4181,7 +4207,7 @@ impl<'a> DoubleEndedIterator for SplitWhitespace<'a> {
 #[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for SplitWhitespace<'_> {}
 
-#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
 impl<'a> Iterator for SplitAsciiWhitespace<'a> {
     type Item = &'a str;
 
@@ -4196,7 +4222,7 @@ impl<'a> Iterator for SplitAsciiWhitespace<'a> {
     }
 }
 
-#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
 impl<'a> DoubleEndedIterator for SplitAsciiWhitespace<'a> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a str> {
@@ -4204,7 +4230,7 @@ impl<'a> DoubleEndedIterator for SplitAsciiWhitespace<'a> {
     }
 }
 
-#[unstable(feature = "split_ascii_whitespace", issue = "48656")]
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
 impl FusedIterator for SplitAsciiWhitespace<'_> {}
 
 /// An iterator of [`u16`] over the string encoded as UTF-16.
@@ -4264,3 +4290,74 @@ impl<'a> Iterator for EncodeUtf16<'a> {
 
 #[stable(feature = "fused", since = "1.26.0")]
 impl FusedIterator for EncodeUtf16<'_> {}
+
+/// The return type of [`str::escape_debug`].
+///
+/// [`str::escape_debug`]: ../../std/primitive.str.html#method.escape_debug
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeDebug<'a> {
+    inner: Chain<
+        Flatten<option::IntoIter<char::EscapeDebug>>,
+        FlatMap<Chars<'a>, char::EscapeDebug, CharEscapeDebugContinue>
+    >,
+}
+
+/// The return type of [`str::escape_default`].
+///
+/// [`str::escape_default`]: ../../std/primitive.str.html#method.escape_default
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeDefault<'a> {
+    inner: FlatMap<Chars<'a>, char::EscapeDefault, CharEscapeDefault>,
+}
+
+/// The return type of [`str::escape_unicode`].
+///
+/// [`str::escape_unicode`]: ../../std/primitive.str.html#method.escape_unicode
+#[stable(feature = "str_escape", since = "1.34.0")]
+#[derive(Clone, Debug)]
+pub struct EscapeUnicode<'a> {
+    inner: FlatMap<Chars<'a>, char::EscapeUnicode, CharEscapeUnicode>,
+}
+
+macro_rules! escape_types_impls {
+    ($( $Name: ident ),+) => {$(
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> fmt::Display for $Name<'a> {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                self.clone().try_for_each(|c| f.write_char(c))
+            }
+        }
+
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> Iterator for $Name<'a> {
+            type Item = char;
+
+            #[inline]
+            fn next(&mut self) -> Option<char> { self.inner.next() }
+
+            #[inline]
+            fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
+
+            #[inline]
+            fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
+                Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
+            {
+                self.inner.try_fold(init, fold)
+            }
+
+            #[inline]
+            fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
+                where Fold: FnMut(Acc, Self::Item) -> Acc,
+            {
+                self.inner.fold(init, fold)
+            }
+        }
+
+        #[stable(feature = "str_escape", since = "1.34.0")]
+        impl<'a> FusedIterator for $Name<'a> {}
+    )+}
+}
+
+escape_types_impls!(EscapeDebug, EscapeDefault, EscapeUnicode);
diff --git a/src/libcore/str/pattern.rs b/src/libcore/str/pattern.rs
index 55a7ba181e527..2571780ad0bab 100644
--- a/src/libcore/str/pattern.rs
+++ b/src/libcore/str/pattern.rs
@@ -1,7 +1,7 @@
 //! The string Pattern API.
 //!
-//! For more details, see the traits `Pattern`, `Searcher`,
-//! `ReverseSearcher` and `DoubleEndedSearcher`.
+//! For more details, see the traits [`Pattern`], [`Searcher`],
+//! [`ReverseSearcher`], and [`DoubleEndedSearcher`].
 
 #![unstable(feature = "pattern",
             reason = "API not fully fleshed out and ready to be stabilized",
@@ -117,7 +117,7 @@ pub unsafe trait Searcher<'a> {
     /// `[Reject(0, 1), Reject(1, 2), Match(2, 5), Reject(5, 8)]`
     fn next(&mut self) -> SearchStep;
 
-    /// Find the next `Match` result. See `next()`
+    /// Finds the next `Match` result. See `next()`
     ///
     /// Unlike next(), there is no guarantee that the returned ranges
     /// of this and next_reject will overlap. This will return (start_match, end_match),
@@ -134,7 +134,7 @@ pub unsafe trait Searcher<'a> {
         }
     }
 
-    /// Find the next `Reject` result. See `next()` and `next_match()`
+    /// Finds the next `Reject` result. See `next()` and `next_match()`
     ///
     /// Unlike next(), there is no guarantee that the returned ranges
     /// of this and next_match will overlap.
@@ -185,7 +185,7 @@ pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
     /// `[Reject(7, 8), Match(4, 7), Reject(1, 4), Reject(0, 1)]`
     fn next_back(&mut self) -> SearchStep;
 
-    /// Find the next `Match` result. See `next_back()`
+    /// Finds the next `Match` result. See `next_back()`
     #[inline]
     fn next_match_back(&mut self) -> Option<(usize, usize)>{
         loop {
@@ -197,7 +197,7 @@ pub unsafe trait ReverseSearcher<'a>: Searcher<'a> {
         }
     }
 
-    /// Find the next `Reject` result. See `next_back()`
+    /// Finds the next `Reject` result. See `next_back()`
     #[inline]
     fn next_reject_back(&mut self) -> Option<(usize, usize)>{
         loop {
diff --git a/src/libcore/sync/atomic.rs b/src/libcore/sync/atomic.rs
index 99e6365d15ec0..d0ee5fa9e6b31 100644
--- a/src/libcore/sync/atomic.rs
+++ b/src/libcore/sync/atomic.rs
@@ -5,13 +5,16 @@
 //! types.
 //!
 //! This module defines atomic versions of a select number of primitive
-//! types, including [`AtomicBool`], [`AtomicIsize`], and [`AtomicUsize`].
+//! types, including [`AtomicBool`], [`AtomicIsize`], [`AtomicUsize`],
+//! [`AtomicI8`], [`AtomicU16`], etc.
 //! Atomic types present operations that, when used correctly, synchronize
 //! updates between threads.
 //!
 //! [`AtomicBool`]: struct.AtomicBool.html
 //! [`AtomicIsize`]: struct.AtomicIsize.html
 //! [`AtomicUsize`]: struct.AtomicUsize.html
+//! [`AtomicI8`]: struct.AtomicI8.html
+//! [`AtomicU16`]: struct.AtomicU16.html
 //!
 //! Each method takes an [`Ordering`] which represents the strength of
 //! the memory barrier for that operation. These orderings are the
@@ -31,11 +34,46 @@
 //! [`Sync`]: ../../marker/trait.Sync.html
 //! [arc]: ../../../std/sync/struct.Arc.html
 //!
-//! Most atomic types may be stored in static variables, initialized using
-//! the provided static initializers like [`ATOMIC_BOOL_INIT`]. Atomic statics
+//! Atomic types may be stored in static variables, initialized using
+//! the constant initializers like [`AtomicBool::new`]. Atomic statics
 //! are often used for lazy global initialization.
 //!
-//! [`ATOMIC_BOOL_INIT`]: constant.ATOMIC_BOOL_INIT.html
+//! [`AtomicBool::new`]: struct.AtomicBool.html#method.new
+//!
+//! # Portability
+//!
+//! All atomic types in this module are guaranteed to be [lock-free] if they're
+//! available. This means they don't internally acquire a global mutex. Atomic
+//! types and operations are not guaranteed to be wait-free. This means that
+//! operations like `fetch_or` may be implemented with a compare-and-swap loop.
+//!
+//! Atomic operations may be implemented at the instruction layer with
+//! larger-size atomics. For example some platforms use 4-byte atomic
+//! instructions to implement `AtomicI8`. Note that this emulation should not
+//! have an impact on correctness of code, it's just something to be aware of.
+//!
+//! The atomic types in this module may not be available on all platforms. The
+//! atomic types here are all widely available, however, and can generally be
+//! relied upon existing. Some notable exceptions are:
+//!
+//! * PowerPC and MIPS platforms with 32-bit pointers do not have `AtomicU64` or
+//!   `AtomicI64` types.
+//! * ARM platforms like `armv5te` that aren't for Linux do not have any atomics
+//!   at all.
+//! * ARM targets with `thumbv6m` do not have atomic operations at all.
+//!
+//! Note that future platforms may be added that also do not have support for
+//! some atomic operations. Maximally portable code will want to be careful
+//! about which atomic types are used. `AtomicUsize` and `AtomicIsize` are
+//! generally the most portable, but even then they're not available everywhere.
+//! For reference, the `std` library requires pointer-sized atomics, although
+//! `core` does not.
+//!
+//! Currently you'll need to use `#[cfg(target_arch)]` primarily to
+//! conditionally compile in code with atomics. There is an unstable
+//! `#[cfg(target_has_atomic)]` as well which may be stabilized in the future.
+//!
+//! [lock-free]: https://en.wikipedia.org/wiki/Non-blocking_algorithm
 //!
 //! # Examples
 //!
@@ -66,9 +104,9 @@
 //! Keep a global count of live threads:
 //!
 //! ```
-//! use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
+//! use std::sync::atomic::{AtomicUsize, Ordering};
 //!
-//! static GLOBAL_THREAD_COUNT: AtomicUsize = ATOMIC_USIZE_INIT;
+//! static GLOBAL_THREAD_COUNT: AtomicUsize = AtomicUsize::new(0);
 //!
 //! let old_thread_count = GLOBAL_THREAD_COUNT.fetch_add(1, Ordering::SeqCst);
 //! println!("live threads: {}", old_thread_count + 1);
@@ -84,6 +122,8 @@ use intrinsics;
 use cell::UnsafeCell;
 use fmt;
 
+use hint::spin_loop;
+
 /// Save power or switch hyperthreads in a busy-wait spin-loop.
 ///
 /// This function is deliberately more primitive than
@@ -96,15 +136,7 @@ use fmt;
 #[inline]
 #[stable(feature = "spin_loop_hint", since = "1.24.0")]
 pub fn spin_loop_hint() {
-    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
-    unsafe {
-        asm!("pause" ::: "memory" : "volatile");
-    }
-
-    #[cfg(target_arch = "aarch64")]
-    unsafe {
-        asm!("yield" ::: "memory" : "volatile");
-    }
+    spin_loop()
 }
 
 /// A boolean type which can be safely shared between threads.
@@ -258,6 +290,15 @@ pub enum Ordering {
 /// [`AtomicBool`]: struct.AtomicBool.html
 #[cfg(target_has_atomic = "8")]
 #[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(stage0), rustc_deprecated(
+    since = "1.34.0",
+    reason = "the `new` function is now preferred",
+    suggestion = "AtomicBool::new(false)",
+))]
+#[cfg_attr(stage0, rustc_deprecated(
+    since = "1.34.0",
+    reason = "the `new` function is now preferred",
+))]
 pub const ATOMIC_BOOL_INIT: AtomicBool = AtomicBool::new(false);
 
 #[cfg(target_has_atomic = "8")]
@@ -1090,10 +1131,12 @@ macro_rules! atomic_int {
      $stable_access:meta,
      $stable_from:meta,
      $stable_nand:meta,
+     $stable_init_const:meta,
      $s_int_type:expr, $int_ref:expr,
      $extra_feature:expr,
      $min_fn:ident, $max_fn:ident,
      $align:expr,
+     $atomic_new:expr,
      $int_type:ident $atomic_type:ident $atomic_init:ident) => {
         /// An integer type which can be safely shared between threads.
         ///
@@ -1103,7 +1146,8 @@ macro_rules! atomic_int {
         /// `](
         #[doc = $int_ref]
         /// ). For more about the differences between atomic types and
-        /// non-atomic types, please see the [module-level documentation].
+        /// non-atomic types as well as information about the portability of
+        /// this type, please see the [module-level documentation].
         ///
         /// [module-level documentation]: index.html
         #[$stable]
@@ -1113,7 +1157,16 @@ macro_rules! atomic_int {
         }
 
         /// An atomic integer initialized to `0`.
-        #[$stable]
+        #[$stable_init_const]
+        #[cfg_attr(stage0, rustc_deprecated(
+            since = "1.34.0",
+            reason = "the `new` function is now preferred",
+        ))]
+        #[cfg_attr(not(stage0), rustc_deprecated(
+            since = "1.34.0",
+            reason = "the `new` function is now preferred",
+            suggestion = $atomic_new,
+        ))]
         pub const $atomic_init: $atomic_type = $atomic_type::new(0);
 
         #[$stable]
@@ -1833,114 +1886,130 @@ assert_eq!(min_foo, 12);
 
 #[cfg(target_has_atomic = "8")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "i8", "../../../std/primitive.i8.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_min, atomic_max,
     1,
+    "AtomicI8::new(0)",
     i8 AtomicI8 ATOMIC_I8_INIT
 }
 #[cfg(target_has_atomic = "8")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "u8", "../../../std/primitive.u8.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_umin, atomic_umax,
     1,
+    "AtomicU8::new(0)",
     u8 AtomicU8 ATOMIC_U8_INIT
 }
 #[cfg(target_has_atomic = "16")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "i16", "../../../std/primitive.i16.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_min, atomic_max,
     2,
+    "AtomicI16::new(0)",
     i16 AtomicI16 ATOMIC_I16_INIT
 }
 #[cfg(target_has_atomic = "16")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "u16", "../../../std/primitive.u16.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_umin, atomic_umax,
     2,
+    "AtomicU16::new(0)",
     u16 AtomicU16 ATOMIC_U16_INIT
 }
 #[cfg(target_has_atomic = "32")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "i32", "../../../std/primitive.i32.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_min, atomic_max,
     4,
+    "AtomicI32::new(0)",
     i32 AtomicI32 ATOMIC_I32_INIT
 }
 #[cfg(target_has_atomic = "32")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "u32", "../../../std/primitive.u32.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_umin, atomic_umax,
     4,
+    "AtomicU32::new(0)",
     u32 AtomicU32 ATOMIC_U32_INIT
 }
 #[cfg(target_has_atomic = "64")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "i64", "../../../std/primitive.i64.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_min, atomic_max,
     8,
+    "AtomicI64::new(0)",
     i64 AtomicI64 ATOMIC_I64_INIT
 }
 #[cfg(target_has_atomic = "64")]
 atomic_int! {
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
-    unstable(feature = "integer_atomics", issue = "32976"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
+    stable(feature = "integer_atomics_stable", since = "1.34.0"),
     unstable(feature = "integer_atomics", issue = "32976"),
     "u64", "../../../std/primitive.u64.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_umin, atomic_umax,
     8,
+    "AtomicU64::new(0)",
     u64 AtomicU64 ATOMIC_U64_INIT
 }
 #[cfg(target_has_atomic = "128")]
@@ -1951,10 +2020,12 @@ atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
+    unstable(feature = "integer_atomics", issue = "32976"),
     "i128", "../../../std/primitive.i128.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_min, atomic_max,
     16,
+    "AtomicI128::new(0)",
     i128 AtomicI128 ATOMIC_I128_INIT
 }
 #[cfg(target_has_atomic = "128")]
@@ -1965,10 +2036,12 @@ atomic_int! {
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
     unstable(feature = "integer_atomics", issue = "32976"),
+    unstable(feature = "integer_atomics", issue = "32976"),
     "u128", "../../../std/primitive.u128.html",
     "#![feature(integer_atomics)]\n\n",
     atomic_umin, atomic_umax,
     16,
+    "AtomicU128::new(0)",
     u128 AtomicU128 ATOMIC_U128_INIT
 }
 #[cfg(target_pointer_width = "16")]
@@ -1991,10 +2064,12 @@ atomic_int!{
     stable(feature = "atomic_access", since = "1.15.0"),
     stable(feature = "atomic_from", since = "1.23.0"),
     stable(feature = "atomic_nand", since = "1.27.0"),
+    stable(feature = "rust1", since = "1.0.0"),
     "isize", "../../../std/primitive.isize.html",
     "",
     atomic_min, atomic_max,
     ptr_width!(),
+    "AtomicIsize::new(0)",
     isize AtomicIsize ATOMIC_ISIZE_INIT
 }
 #[cfg(target_has_atomic = "ptr")]
@@ -2005,10 +2080,12 @@ atomic_int!{
     stable(feature = "atomic_access", since = "1.15.0"),
     stable(feature = "atomic_from", since = "1.23.0"),
     stable(feature = "atomic_nand", since = "1.27.0"),
+    stable(feature = "rust1", since = "1.0.0"),
     "usize", "../../../std/primitive.usize.html",
     "",
     atomic_umin, atomic_umax,
     ptr_width!(),
+    "AtomicUsize::new(0)",
     usize AtomicUsize ATOMIC_USIZE_INIT
 }
 
@@ -2378,12 +2455,11 @@ pub fn fence(order: Ordering) {
 ///
 /// ```
 /// use std::sync::atomic::{AtomicBool, AtomicUsize};
-/// use std::sync::atomic::{ATOMIC_BOOL_INIT, ATOMIC_USIZE_INIT};
 /// use std::sync::atomic::Ordering;
 /// use std::sync::atomic::compiler_fence;
 ///
-/// static IMPORTANT_VARIABLE: AtomicUsize = ATOMIC_USIZE_INIT;
-/// static IS_READY: AtomicBool = ATOMIC_BOOL_INIT;
+/// static IMPORTANT_VARIABLE: AtomicUsize = AtomicUsize::new(0);
+/// static IS_READY: AtomicBool = AtomicBool::new(false);
 ///
 /// fn main() {
 ///     IMPORTANT_VARIABLE.store(42, Ordering::Relaxed);
diff --git a/src/libcore/task/mod.rs b/src/libcore/task/mod.rs
index 9552e53ebf849..9b8f598116200 100644
--- a/src/libcore/task/mod.rs
+++ b/src/libcore/task/mod.rs
@@ -8,4 +8,4 @@ mod poll;
 pub use self::poll::Poll;
 
 mod wake;
-pub use self::wake::{Waker, LocalWaker, UnsafeWake};
+pub use self::wake::{Waker, RawWaker, RawWakerVTable};
diff --git a/src/libcore/task/poll.rs b/src/libcore/task/poll.rs
index 27b1139e15c79..c811f96ace3ba 100644
--- a/src/libcore/task/poll.rs
+++ b/src/libcore/task/poll.rs
@@ -7,6 +7,7 @@ use result::Result;
 
 /// Indicates whether a value is available or if the current task has been
 /// scheduled to receive a wakeup instead.
+#[must_use = "this `Poll` may be a `Pending` variant, which should be handled"]
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub enum Poll<T> {
     /// Represents that a value is immediately ready.
@@ -21,7 +22,7 @@ pub enum Poll<T> {
 }
 
 impl<T> Poll<T> {
-    /// Change the ready value of this `Poll` with the closure provided
+    /// Changes the ready value of this `Poll` with the closure provided.
     pub fn map<U, F>(self, f: F) -> Poll<U>
         where F: FnOnce(T) -> U
     {
@@ -31,7 +32,7 @@ impl<T> Poll<T> {
         }
     }
 
-    /// Returns whether this is `Poll::Ready`
+    /// Returns `true` if this is `Poll::Ready`
     #[inline]
     pub fn is_ready(&self) -> bool {
         match *self {
@@ -40,7 +41,7 @@ impl<T> Poll<T> {
         }
     }
 
-    /// Returns whether this is `Poll::Pending`
+    /// Returns `true` if this is `Poll::Pending`
     #[inline]
     pub fn is_pending(&self) -> bool {
         !self.is_ready()
@@ -48,7 +49,7 @@ impl<T> Poll<T> {
 }
 
 impl<T, E> Poll<Result<T, E>> {
-    /// Change the success value of this `Poll` with the closure provided
+    /// Changes the success value of this `Poll` with the closure provided.
     pub fn map_ok<U, F>(self, f: F) -> Poll<Result<U, E>>
         where F: FnOnce(T) -> U
     {
@@ -59,7 +60,7 @@ impl<T, E> Poll<Result<T, E>> {
         }
     }
 
-    /// Change the error value of this `Poll` with the closure provided
+    /// Changes the error value of this `Poll` with the closure provided.
     pub fn map_err<U, F>(self, f: F) -> Poll<Result<T, U>>
         where F: FnOnce(E) -> U
     {
diff --git a/src/libcore/task/wake.rs b/src/libcore/task/wake.rs
index 3f7098f1ef934..21f0a8cea4168 100644
--- a/src/libcore/task/wake.rs
+++ b/src/libcore/task/wake.rs
@@ -4,16 +4,92 @@
 
 use fmt;
 use marker::Unpin;
-use ptr::NonNull;
+
+/// A `RawWaker` allows the implementor of a task executor to create a [`Waker`]
+/// which provides customized wakeup behavior.
+///
+/// [vtable]: https://en.wikipedia.org/wiki/Virtual_method_table
+///
+/// It consists of a data pointer and a [virtual function pointer table (vtable)][vtable] that
+/// customizes the behavior of the `RawWaker`.
+#[derive(PartialEq, Debug)]
+pub struct RawWaker {
+    /// A data pointer, which can be used to store arbitrary data as required
+    /// by the executor. This could be e.g. a type-erased pointer to an `Arc`
+    /// that is associated with the task.
+    /// The value of this field gets passed to all functions that are part of
+    /// the vtable as the first parameter.
+    data: *const (),
+    /// Virtual function pointer table that customizes the behavior of this waker.
+    vtable: &'static RawWakerVTable,
+}
+
+impl RawWaker {
+    /// Creates a new `RawWaker` from the provided `data` pointer and `vtable`.
+    ///
+    /// The `data` pointer can be used to store arbitrary data as required
+    /// by the executor. This could be e.g. a type-erased pointer to an `Arc`
+    /// that is associated with the task.
+    /// The value of this poiner will get passed to all functions that are part
+    /// of the `vtable` as the first parameter.
+    ///
+    /// The `vtable` customizes the behavior of a `Waker` which gets created
+    /// from a `RawWaker`. For each operation on the `Waker`, the associated
+    /// function in the `vtable` of the underlying `RawWaker` will be called.
+    pub const fn new(data: *const (), vtable: &'static RawWakerVTable) -> RawWaker {
+        RawWaker {
+            data,
+            vtable,
+        }
+    }
+}
+
+/// A virtual function pointer table (vtable) that specifies the behavior
+/// of a [`RawWaker`].
+///
+/// The pointer passed to all functions inside the vtable is the `data` pointer
+/// from the enclosing [`RawWaker`] object.
+///
+/// The functions inside this struct are only intended be called on the `data`
+/// pointer of a properly constructed [`RawWaker`] object from inside the
+/// [`RawWaker`] implementation. Calling one of the contained functions using
+/// any other `data` pointer will cause undefined behavior.
+#[derive(PartialEq, Copy, Clone, Debug)]
+pub struct RawWakerVTable {
+    /// This function will be called when the [`RawWaker`] gets cloned, e.g. when
+    /// the [`Waker`] in which the [`RawWaker`] is stored gets cloned.
+    ///
+    /// The implementation of this function must retain all resources that are
+    /// required for this additional instance of a [`RawWaker`] and associated
+    /// task. Calling `wake` on the resulting [`RawWaker`] should result in a wakeup
+    /// of the same task that would have been awoken by the original [`RawWaker`].
+    pub clone: unsafe fn(*const ()) -> RawWaker,
+
+    /// This function will be called when `wake` is called on the [`Waker`].
+    /// It must wake up the task associated with this [`RawWaker`].
+    ///
+    /// The implemention of this function must not consume the provided data
+    /// pointer.
+    pub wake: unsafe fn(*const ()),
+
+    /// This function gets called when a [`RawWaker`] gets dropped.
+    ///
+    /// The implementation of this function must make sure to release any
+    /// resources that are associated with this instance of a [`RawWaker`] and
+    /// associated task.
+    pub drop: unsafe fn(*const ()),
+}
 
 /// A `Waker` is a handle for waking up a task by notifying its executor that it
 /// is ready to be run.
 ///
-/// This handle contains a trait object pointing to an instance of the `UnsafeWake`
-/// trait, allowing notifications to get routed through it.
+/// This handle encapsulates a [`RawWaker`] instance, which defines the
+/// executor-specific wakeup behavior.
+///
+/// Implements [`Clone`], [`Send`], and [`Sync`].
 #[repr(transparent)]
 pub struct Waker {
-    inner: NonNull<dyn UnsafeWake>,
+    waker: RawWaker,
 }
 
 impl Unpin for Waker {}
@@ -21,264 +97,66 @@ unsafe impl Send for Waker {}
 unsafe impl Sync for Waker {}
 
 impl Waker {
-    /// Constructs a new `Waker` directly.
-    ///
-    /// Note that most code will not need to call this. Implementers of the
-    /// `UnsafeWake` trait will typically provide a wrapper that calls this
-    /// but you otherwise shouldn't call it directly.
-    ///
-    /// If you're working with the standard library then it's recommended to
-    /// use the `Waker::from` function instead which works with the safe
-    /// `Arc` type and the safe `Wake` trait.
-    #[inline]
-    pub unsafe fn new(inner: NonNull<dyn UnsafeWake>) -> Self {
-        Waker { inner }
-    }
-
     /// Wake up the task associated with this `Waker`.
-    #[inline]
     pub fn wake(&self) {
-        unsafe { self.inner.as_ref().wake() }
+        // The actual wakeup call is delegated through a virtual function call
+        // to the implementation which is defined by the executor.
+
+        // SAFETY: This is safe because `Waker::new_unchecked` is the only way
+        // to initialize `wake` and `data` requiring the user to acknowledge
+        // that the contract of `RawWaker` is upheld.
+        unsafe { (self.waker.vtable.wake)(self.waker.data) }
     }
 
-    /// Returns whether or not this `Waker` and `other` awaken the same task.
+    /// Returns whether or not this `Waker` and other `Waker` have awaken the same task.
     ///
     /// This function works on a best-effort basis, and may return false even
     /// when the `Waker`s would awaken the same task. However, if this function
-    /// returns true, it is guaranteed that the `Waker`s will awaken the same
-    /// task.
+    /// returns `true`, it is guaranteed that the `Waker`s will awaken the same task.
     ///
     /// This function is primarily used for optimization purposes.
-    #[inline]
     pub fn will_wake(&self, other: &Waker) -> bool {
-        self.inner == other.inner
+        self.waker == other.waker
     }
 
-    /// Returns whether or not this `Waker` and `other` `LocalWaker` awaken
-    /// the same task.
+    /// Creates a new `Waker` from [`RawWaker`].
     ///
-    /// This function works on a best-effort basis, and may return false even
-    /// when the `Waker`s would awaken the same task. However, if this function
-    /// returns true, it is guaranteed that the `Waker`s will awaken the same
-    /// task.
-    ///
-    /// This function is primarily used for optimization purposes.
-    #[inline]
-    pub fn will_wake_local(&self, other: &LocalWaker) -> bool {
-        self.will_wake(&other.0)
+    /// The behavior of the returned `Waker` is undefined if the contract defined
+    /// in [`RawWaker`]'s and [`RawWakerVTable`]'s documentation is not upheld.
+    /// Therefore this method is unsafe.
+    pub unsafe fn new_unchecked(waker: RawWaker) -> Waker {
+        Waker {
+            waker,
+        }
     }
 }
 
 impl Clone for Waker {
-    #[inline]
     fn clone(&self) -> Self {
-        unsafe {
-            self.inner.as_ref().clone_raw()
+        Waker {
+            // SAFETY: This is safe because `Waker::new_unchecked` is the only way
+            // to initialize `clone` and `data` requiring the user to acknowledge
+            // that the contract of [`RawWaker`] is upheld.
+            waker: unsafe { (self.waker.vtable.clone)(self.waker.data) },
         }
     }
 }
 
-impl fmt::Debug for Waker {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("Waker")
-            .finish()
-    }
-}
-
 impl Drop for Waker {
-    #[inline]
     fn drop(&mut self) {
-        unsafe {
-            self.inner.as_ref().drop_raw()
-        }
-    }
-}
-
-/// A `LocalWaker` is a handle for waking up a task by notifying its executor that it
-/// is ready to be run.
-///
-/// This is similar to the `Waker` type, but cannot be sent across threads.
-/// Task executors can use this type to implement more optimized single-threaded wakeup
-/// behavior.
-#[repr(transparent)]
-#[derive(Clone)]
-pub struct LocalWaker(Waker);
-
-impl Unpin for LocalWaker {}
-impl !Send for LocalWaker {}
-impl !Sync for LocalWaker {}
-
-impl LocalWaker {
-    /// Constructs a new `LocalWaker` directly.
-    ///
-    /// Note that most code will not need to call this. Implementers of the
-    /// `UnsafeWake` trait will typically provide a wrapper that calls this
-    /// but you otherwise shouldn't call it directly.
-    ///
-    /// If you're working with the standard library then it's recommended to
-    /// use the `local_waker_from_nonlocal` or `local_waker` to convert a `Waker`
-    /// into a `LocalWaker`.
-    ///
-    /// For this function to be used safely, it must be sound to call `inner.wake_local()`
-    /// on the current thread.
-    #[inline]
-    pub unsafe fn new(inner: NonNull<dyn UnsafeWake>) -> Self {
-        LocalWaker(Waker::new(inner))
-    }
-
-    /// Borrows this `LocalWaker` as a `Waker`.
-    ///
-    /// `Waker` is nearly identical to `LocalWaker`, but is threadsafe
-    /// (implements `Send` and `Sync`).
-    #[inline]
-    pub fn as_waker(&self) -> &Waker {
-        &self.0
-    }
-
-    /// Converts this `LocalWaker` into a `Waker`.
-    ///
-    /// `Waker` is nearly identical to `LocalWaker`, but is threadsafe
-    /// (implements `Send` and `Sync`).
-    #[inline]
-    pub fn into_waker(self) -> Waker {
-        self.0
-    }
-
-    /// Wake up the task associated with this `LocalWaker`.
-    #[inline]
-    pub fn wake(&self) {
-        unsafe { self.0.inner.as_ref().wake_local() }
-    }
-
-    /// Returns whether or not this `LocalWaker` and `other` `LocalWaker` awaken the same task.
-    ///
-    /// This function works on a best-effort basis, and may return false even
-    /// when the `LocalWaker`s would awaken the same task. However, if this function
-    /// returns true, it is guaranteed that the `LocalWaker`s will awaken the same
-    /// task.
-    ///
-    /// This function is primarily used for optimization purposes.
-    #[inline]
-    pub fn will_wake(&self, other: &LocalWaker) -> bool {
-        self.0.will_wake(&other.0)
-    }
-
-    /// Returns whether or not this `LocalWaker` and `other` `Waker` awaken the same task.
-    ///
-    /// This function works on a best-effort basis, and may return false even
-    /// when the `Waker`s would awaken the same task. However, if this function
-    /// returns true, it is guaranteed that the `LocalWaker`s will awaken the same
-    /// task.
-    ///
-    /// This function is primarily used for optimization purposes.
-    #[inline]
-    pub fn will_wake_nonlocal(&self, other: &Waker) -> bool {
-        self.0.will_wake(other)
-    }
-}
-
-impl From<LocalWaker> for Waker {
-    /// Converts a `LocalWaker` into a `Waker`.
-    ///
-    /// This conversion turns a `!Sync` `LocalWaker` into a `Sync` `Waker`, allowing a wakeup
-    /// object to be sent to another thread, but giving up its ability to do specialized
-    /// thread-local wakeup behavior.
-    #[inline]
-    fn from(local_waker: LocalWaker) -> Self {
-        local_waker.0
+        // SAFETY: This is safe because `Waker::new_unchecked` is the only way
+        // to initialize `drop` and `data` requiring the user to acknowledge
+        // that the contract of `RawWaker` is upheld.
+        unsafe { (self.waker.vtable.drop)(self.waker.data) }
     }
 }
 
-impl fmt::Debug for LocalWaker {
+impl fmt::Debug for Waker {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("LocalWaker")
+        let vtable_ptr = self.waker.vtable as *const RawWakerVTable;
+        f.debug_struct("Waker")
+            .field("data", &self.waker.data)
+            .field("vtable", &vtable_ptr)
             .finish()
     }
 }
-
-/// An unsafe trait for implementing custom memory management for a `Waker` or `LocalWaker`.
-///
-/// A `Waker` conceptually is a cloneable trait object for `Wake`, and is
-/// most often essentially just `Arc<dyn Wake>`. However, in some contexts
-/// (particularly `no_std`), it's desirable to avoid `Arc` in favor of some
-/// custom memory management strategy. This trait is designed to allow for such
-/// customization.
-///
-/// When using `std`, a default implementation of the `UnsafeWake` trait is provided for
-/// `Arc<T>` where `T: Wake`.
-pub unsafe trait UnsafeWake: Send + Sync {
-    /// Creates a clone of this `UnsafeWake` and stores it behind a `Waker`.
-    ///
-    /// This function will create a new uniquely owned handle that under the
-    /// hood references the same notification instance. In other words calls
-    /// to `wake` on the returned handle should be equivalent to calls to
-    /// `wake` on this handle.
-    ///
-    /// # Unsafety
-    ///
-    /// This function is unsafe to call because it's asserting the `UnsafeWake`
-    /// value is in a consistent state, i.e., hasn't been dropped.
-    unsafe fn clone_raw(&self) -> Waker;
-
-    /// Drops this instance of `UnsafeWake`, deallocating resources
-    /// associated with it.
-    ///
-    /// FIXME(cramertj)
-    /// This method is intended to have a signature such as:
-    ///
-    /// ```ignore (not-a-doctest)
-    /// fn drop_raw(self: *mut Self);
-    /// ```
-    ///
-    /// Unfortunately in Rust today that signature is not object safe.
-    /// Nevertheless it's recommended to implement this function *as if* that
-    /// were its signature. As such it is not safe to call on an invalid
-    /// pointer, nor is the validity of the pointer guaranteed after this
-    /// function returns.
-    ///
-    /// # Unsafety
-    ///
-    /// This function is unsafe to call because it's asserting the `UnsafeWake`
-    /// value is in a consistent state, i.e., hasn't been dropped.
-    unsafe fn drop_raw(&self);
-
-    /// Indicates that the associated task is ready to make progress and should
-    /// be `poll`ed.
-    ///
-    /// Executors generally maintain a queue of "ready" tasks; `wake` should place
-    /// the associated task onto this queue.
-    ///
-    /// # Panics
-    ///
-    /// Implementations should avoid panicking, but clients should also be prepared
-    /// for panics.
-    ///
-    /// # Unsafety
-    ///
-    /// This function is unsafe to call because it's asserting the `UnsafeWake`
-    /// value is in a consistent state, i.e., hasn't been dropped.
-    unsafe fn wake(&self);
-
-    /// Indicates that the associated task is ready to make progress and should
-    /// be `poll`ed. This function is the same as `wake`, but can only be called
-    /// from the thread that this `UnsafeWake` is "local" to. This allows for
-    /// implementors to provide specialized wakeup behavior specific to the current
-    /// thread. This function is called by `LocalWaker::wake`.
-    ///
-    /// Executors generally maintain a queue of "ready" tasks; `wake_local` should place
-    /// the associated task onto this queue.
-    ///
-    /// # Panics
-    ///
-    /// Implementations should avoid panicking, but clients should also be prepared
-    /// for panics.
-    ///
-    /// # Unsafety
-    ///
-    /// This function is unsafe to call because it's asserting the `UnsafeWake`
-    /// value is in a consistent state, i.e., hasn't been dropped, and that the
-    /// `UnsafeWake` hasn't moved from the thread on which it was created.
-    unsafe fn wake_local(&self) {
-        self.wake()
-    }
-}
diff --git a/src/libcore/tests/cell.rs b/src/libcore/tests/cell.rs
index 56f295dff8e43..b16416022c04e 100644
--- a/src/libcore/tests/cell.rs
+++ b/src/libcore/tests/cell.rs
@@ -109,6 +109,7 @@ fn double_borrow_single_release_no_borrow_mut() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn discard_doesnt_unborrow() {
     let x = RefCell::new(0);
     let _b = x.borrow();
@@ -349,6 +350,7 @@ fn refcell_ref_coercion() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn refcell_swap_borrows() {
     let x = RefCell::new(0);
     let _b = x.borrow();
@@ -358,6 +360,7 @@ fn refcell_swap_borrows() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn refcell_replace_borrows() {
     let x = RefCell::new(0);
     let _b = x.borrow();
diff --git a/src/libcore/tests/fmt/mod.rs b/src/libcore/tests/fmt/mod.rs
index d86e21cf40b6e..df1deeaeb97b7 100644
--- a/src/libcore/tests/fmt/mod.rs
+++ b/src/libcore/tests/fmt/mod.rs
@@ -3,6 +3,7 @@ mod float;
 mod num;
 
 #[test]
+#[cfg(not(miri))] // Miri cannot print pointers
 fn test_format_flags() {
     // No residual flags left by pointer formatting
     let p = "".as_ptr();
@@ -12,6 +13,7 @@ fn test_format_flags() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri cannot print pointers
 fn test_pointer_formats_data_pointer() {
     let b: &[u8] = b"";
     let s: &str = "";
diff --git a/src/libcore/tests/hash/mod.rs b/src/libcore/tests/hash/mod.rs
index 135f4dfcac7d5..1000088e6b063 100644
--- a/src/libcore/tests/hash/mod.rs
+++ b/src/libcore/tests/hash/mod.rs
@@ -73,9 +73,11 @@ fn test_writer_hasher() {
     let cs: &mut [u8] = &mut [1, 2, 3];
     let ptr = cs.as_ptr();
     let slice_ptr = cs as *const [u8];
+    #[cfg(not(miri))] // Miri cannot hash pointers
     assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
 
     let slice_ptr = cs as *mut [u8];
+    #[cfg(not(miri))] // Miri cannot hash pointers
     assert_eq!(hash(&slice_ptr), hash(&ptr) + cs.len() as u64);
 }
 
diff --git a/src/libcore/tests/iter.rs b/src/libcore/tests/iter.rs
index 3944bc749d029..9b76a4af98824 100644
--- a/src/libcore/tests/iter.rs
+++ b/src/libcore/tests/iter.rs
@@ -253,6 +253,7 @@ fn test_iterator_step_by_nth_overflow() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_iterator_step_by_zero() {
     let mut it = (0..).step_by(0);
     it.next();
@@ -877,7 +878,7 @@ fn test_iterator_flat_map() {
     assert_eq!(i, ys.len());
 }
 
-/// Test `FlatMap::fold` with items already picked off the front and back,
+/// Tests `FlatMap::fold` with items already picked off the front and back,
 /// to make sure all parts of the `FlatMap` are folded correctly.
 #[test]
 fn test_iterator_flat_map_fold() {
@@ -915,7 +916,7 @@ fn test_iterator_flatten() {
     assert_eq!(i, ys.len());
 }
 
-/// Test `Flatten::fold` with items already picked off the front and back,
+/// Tests `Flatten::fold` with items already picked off the front and back,
 /// to make sure all parts of the `Flatten` are folded correctly.
 #[test]
 fn test_iterator_flatten_fold() {
@@ -1413,6 +1414,7 @@ fn test_rposition() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_rposition_panic() {
     let v: [(Box<_>, Box<_>); 4] =
         [(box 0, box 0), (box 0, box 0),
@@ -2235,3 +2237,16 @@ fn test_monad_laws_associativity() {
     assert_eq!((0..10).flat_map(f).flat_map(g).sum::<usize>(),
                 (0..10).flat_map(|x| f(x).flat_map(g)).sum::<usize>());
 }
+
+#[test]
+fn test_is_sorted() {
+    assert!([1, 2, 2, 9].iter().is_sorted());
+    assert!(![1, 3, 2].iter().is_sorted());
+    assert!([0].iter().is_sorted());
+    assert!(std::iter::empty::<i32>().is_sorted());
+    assert!(![0.0, 1.0, std::f32::NAN].iter().is_sorted());
+    assert!([-2, -1, 0, 3].iter().is_sorted());
+    assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
+    assert!(!["c", "bb", "aaa"].iter().is_sorted());
+    assert!(["c", "bb", "aaa"].iter().is_sorted_by_key(|s| s.len()));
+}
diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs
index a9b8decfd0262..4cd734bad90a4 100644
--- a/src/libcore/tests/lib.rs
+++ b/src/libcore/tests/lib.rs
@@ -10,10 +10,10 @@
 #![feature(flt2dec)]
 #![feature(fmt_internals)]
 #![feature(hashmap_internals)]
+#![feature(is_sorted)]
 #![feature(iter_copied)]
 #![feature(iter_nth_back)]
 #![feature(iter_once_with)]
-#![feature(iter_unfold)]
 #![feature(pattern)]
 #![feature(range_is_empty)]
 #![feature(raw)]
diff --git a/src/libcore/tests/nonzero.rs b/src/libcore/tests/nonzero.rs
index c813bf20cb61a..4532568ee0c16 100644
--- a/src/libcore/tests/nonzero.rs
+++ b/src/libcore/tests/nonzero.rs
@@ -1,4 +1,4 @@
-use core::num::NonZeroU32;
+use core::num::{NonZeroU32, NonZeroI32};
 use core::option::Option;
 use core::option::Option::{Some, None};
 use std::mem::size_of;
@@ -13,6 +13,7 @@ fn test_create_nonzero_instance() {
 #[test]
 fn test_size_nonzero_in_option() {
     assert_eq!(size_of::<NonZeroU32>(), size_of::<Option<NonZeroU32>>());
+    assert_eq!(size_of::<NonZeroI32>(), size_of::<Option<NonZeroI32>>());
 }
 
 #[test]
@@ -118,3 +119,10 @@ fn test_from_nonzero() {
     let num: u32 = nz.into();
     assert_eq!(num, 1u32);
 }
+
+#[test]
+fn test_from_signed_nonzero() {
+    let nz = NonZeroI32::new(1).unwrap();
+    let num: i32 = nz.into();
+    assert_eq!(num, 1i32);
+}
diff --git a/src/libcore/tests/num/bignum.rs b/src/libcore/tests/num/bignum.rs
index b873f1dd0652f..956c22c998219 100644
--- a/src/libcore/tests/num/bignum.rs
+++ b/src/libcore/tests/num/bignum.rs
@@ -3,6 +3,7 @@ use core::num::bignum::tests::Big8x3 as Big;
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_from_u64_overflow() {
     Big::from_u64(0x1000000);
 }
@@ -19,12 +20,14 @@ fn test_add() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_add_overflow_1() {
     Big::from_small(1).add(&Big::from_u64(0xffffff));
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_add_overflow_2() {
     Big::from_u64(0xffffff).add(&Big::from_small(1));
 }
@@ -42,6 +45,7 @@ fn test_add_small() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_add_small_overflow() {
     Big::from_u64(0xffffff).add_small(1);
 }
@@ -57,12 +61,14 @@ fn test_sub() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_sub_underflow_1() {
     Big::from_u64(0x10665).sub(&Big::from_u64(0x10666));
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_sub_underflow_2() {
     Big::from_small(0).sub(&Big::from_u64(0x123456));
 }
@@ -76,6 +82,7 @@ fn test_mul_small() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_small_overflow() {
     Big::from_u64(0x800000).mul_small(2);
 }
@@ -94,12 +101,14 @@ fn test_mul_pow2() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_pow2_overflow_1() {
     Big::from_u64(0x1).mul_pow2(24);
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_pow2_overflow_2() {
     Big::from_u64(0x123).mul_pow2(16);
 }
@@ -118,12 +127,14 @@ fn test_mul_pow5() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_pow5_overflow_1() {
     Big::from_small(1).mul_pow5(12);
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_pow5_overflow_2() {
     Big::from_small(230).mul_pow5(8);
 }
@@ -141,12 +152,14 @@ fn test_mul_digits() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_digits_overflow_1() {
     Big::from_u64(0x800000).mul_digits(&[2]);
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_mul_digits_overflow_2() {
     Big::from_u64(0x1000).mul_digits(&[0, 0x10]);
 }
@@ -206,6 +219,7 @@ fn test_get_bit() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_get_bit_out_of_range() {
     Big::from_small(42).get_bit(24);
 }
diff --git a/src/libcore/tests/num/dec2flt/mod.rs b/src/libcore/tests/num/dec2flt/mod.rs
index 8f1cd32c3563c..faeaabbf95ada 100644
--- a/src/libcore/tests/num/dec2flt/mod.rs
+++ b/src/libcore/tests/num/dec2flt/mod.rs
@@ -52,6 +52,7 @@ fn large() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn subnormals() {
     test_literal!(5e-324);
     test_literal!(91e-324);
@@ -63,6 +64,7 @@ fn subnormals() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn infinity() {
     test_literal!(1e400);
     test_literal!(1e309);
diff --git a/src/libcore/tests/num/flt2dec/mod.rs b/src/libcore/tests/num/flt2dec/mod.rs
index fed9ce73b2a8e..d362c7994d806 100644
--- a/src/libcore/tests/num/flt2dec/mod.rs
+++ b/src/libcore/tests/num/flt2dec/mod.rs
@@ -1,3 +1,5 @@
+#![cfg(not(miri))] // Miri does not implement ldexp, which most tests here need
+
 use std::prelude::v1::*;
 use std::{str, i16, f32, f64, fmt};
 
diff --git a/src/libcore/tests/option.rs b/src/libcore/tests/option.rs
index b059b134868d9..87ce2720c5918 100644
--- a/src/libcore/tests/option.rs
+++ b/src/libcore/tests/option.rs
@@ -69,6 +69,7 @@ fn test_option_dance() {
 }
 
 #[test] #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_option_too_much_dance() {
     struct A;
     let mut y = Some(A);
@@ -129,6 +130,7 @@ fn test_unwrap() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_unwrap_panic1() {
     let x: Option<isize> = None;
     x.unwrap();
@@ -136,6 +138,7 @@ fn test_unwrap_panic1() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_unwrap_panic2() {
     let x: Option<String> = None;
     x.unwrap();
diff --git a/src/libcore/tests/ptr.rs b/src/libcore/tests/ptr.rs
index 65c1a3e0254d2..03fe1fe5a7cf8 100644
--- a/src/libcore/tests/ptr.rs
+++ b/src/libcore/tests/ptr.rs
@@ -44,13 +44,13 @@ fn test_is_null() {
     let p: *const isize = null();
     assert!(p.is_null());
 
-    let q = unsafe { p.offset(1) };
+    let q = p.wrapping_offset(1);
     assert!(!q.is_null());
 
     let mp: *mut isize = null_mut();
     assert!(mp.is_null());
 
-    let mq = unsafe { mp.offset(1) };
+    let mq = mp.wrapping_offset(1);
     assert!(!mq.is_null());
 
     // Pointers to unsized types -- slices
@@ -145,6 +145,7 @@ fn test_as_ref() {
 }
 
 #[test]
+#[cfg(not(miri))] // This test is UB according to Stacked Borrows
 fn test_as_mut() {
     unsafe {
         let p: *mut isize = null_mut();
@@ -221,8 +222,11 @@ fn test_ptr_subtraction() {
         let m_start = xs_mut.as_mut_ptr();
         let mut m_ptr = m_start.offset(9);
 
-        while m_ptr >= m_start {
+        loop {
             *m_ptr += *m_ptr;
+            if m_ptr == m_start {
+                break;
+            }
             m_ptr = m_ptr.offset(-1);
         }
 
@@ -249,6 +253,7 @@ fn test_unsized_nonnull() {
 
 #[test]
 #[allow(warnings)]
+#[cfg(not(miri))] // Miri cannot hash pointers
 // Have a symbol for the test below. It doesn’t need to be an actual variadic function, match the
 // ABI, or even point to an actual executable code, because the function itself is never invoked.
 #[no_mangle]
@@ -288,6 +293,7 @@ fn write_unaligned_drop() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri cannot compute actual alignment of an allocation
 fn align_offset_zst() {
     // For pointers of stride = 0, the pointer is already aligned or it cannot be aligned at
     // all, because no amount of elements will align the pointer.
@@ -302,6 +308,7 @@ fn align_offset_zst() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri cannot compute actual alignment of an allocation
 fn align_offset_stride1() {
     // For pointers of stride = 1, the pointer can always be aligned. The offset is equal to
     // number of bytes.
@@ -318,6 +325,7 @@ fn align_offset_stride1() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri is too slow
 fn align_offset_weird_strides() {
     #[repr(packed)]
     struct A3(u16, u8);
diff --git a/src/libcore/tests/result.rs b/src/libcore/tests/result.rs
index 1fab07526a07f..bbc8568517667 100644
--- a/src/libcore/tests/result.rs
+++ b/src/libcore/tests/result.rs
@@ -117,6 +117,7 @@ fn test_unwrap_or_else() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 pub fn test_unwrap_or_else_panic() {
     fn handler(msg: &'static str) -> isize {
         if msg == "I got this." {
@@ -138,6 +139,7 @@ pub fn test_expect_ok() {
 }
 #[test]
 #[should_panic(expected="Got expected error: \"All good\"")]
+#[cfg(not(miri))] // Miri does not support panics
 pub fn test_expect_err() {
     let err: Result<isize, &'static str> = Err("All good");
     err.expect("Got expected error");
@@ -151,6 +153,7 @@ pub fn test_expect_err_err() {
 }
 #[test]
 #[should_panic(expected="Got expected ok: \"All good\"")]
+#[cfg(not(miri))] // Miri does not support panics
 pub fn test_expect_err_ok() {
     let err: Result<&'static str, isize> = Ok("All good");
     err.expect_err("Got expected ok");
diff --git a/src/libcore/tests/slice.rs b/src/libcore/tests/slice.rs
index 2c96efbda7673..31d16e0e32057 100644
--- a/src/libcore/tests/slice.rs
+++ b/src/libcore/tests/slice.rs
@@ -782,6 +782,7 @@ mod slice_index {
     //  to be used in `should_panic`)
     #[test]
     #[should_panic(expected = "out of range")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn assert_range_eq_can_fail_by_panic() {
         assert_range_eq!([0, 1, 2], 0..5, [0, 1, 2]);
     }
@@ -791,6 +792,7 @@ mod slice_index {
     //  to be used in `should_panic`)
     #[test]
     #[should_panic(expected = "==")]
+    #[cfg(not(miri))] // Miri does not support panics
     fn assert_range_eq_can_fail_by_inequality() {
         assert_range_eq!([0, 1, 2], 0..2, [0, 1, 2]);
     }
@@ -840,6 +842,7 @@ mod slice_index {
 
                 #[test]
                 #[should_panic(expected = $expect_msg)]
+                #[cfg(not(miri))] // Miri does not support panics
                 fn index_fail() {
                     let v = $data;
                     let v: &[_] = &v;
@@ -848,6 +851,7 @@ mod slice_index {
 
                 #[test]
                 #[should_panic(expected = $expect_msg)]
+                #[cfg(not(miri))] // Miri does not support panics
                 fn index_mut_fail() {
                     let mut v = $data;
                     let v: &mut [_] = &mut v;
@@ -1011,6 +1015,7 @@ fn test_rotate_right() {
 
 #[test]
 #[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(miri))] // Miri does not support entropy
 fn sort_unstable() {
     use core::cmp::Ordering::{Equal, Greater, Less};
     use core::slice::heapsort;
@@ -1166,6 +1171,7 @@ pub mod memchr {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri cannot compute actual alignment of an allocation
 fn test_align_to_simple() {
     let bytes = [1u8, 2, 3, 4, 5, 6, 7];
     let (prefix, aligned, suffix) = unsafe { bytes.align_to::<u16>() };
@@ -1189,6 +1195,7 @@ fn test_align_to_zst() {
 }
 
 #[test]
+#[cfg(not(miri))] // Miri cannot compute actual alignment of an allocation
 fn test_align_to_non_trivial() {
     #[repr(align(8))] struct U64(u64, u64);
     #[repr(align(8))] struct U64U64U32(u64, u64, u32);
@@ -1297,6 +1304,7 @@ fn test_copy_within() {
 
 #[test]
 #[should_panic(expected = "src is out of bounds")]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_copy_within_panics_src_too_long() {
     let mut bytes = *b"Hello, World!";
     // The length is only 13, so 14 is out of bounds.
@@ -1305,6 +1313,7 @@ fn test_copy_within_panics_src_too_long() {
 
 #[test]
 #[should_panic(expected = "dest is out of bounds")]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_copy_within_panics_dest_too_long() {
     let mut bytes = *b"Hello, World!";
     // The length is only 13, so a slice of length 4 starting at index 10 is out of bounds.
@@ -1312,8 +1321,24 @@ fn test_copy_within_panics_dest_too_long() {
 }
 #[test]
 #[should_panic(expected = "src end is before src start")]
+#[cfg(not(miri))] // Miri does not support panics
 fn test_copy_within_panics_src_inverted() {
     let mut bytes = *b"Hello, World!";
     // 2 is greater than 1, so this range is invalid.
     bytes.copy_within(2..1, 0);
 }
+
+#[test]
+fn test_is_sorted() {
+    let empty: [i32; 0] = [];
+
+    assert!([1, 2, 2, 9].is_sorted());
+    assert!(![1, 3, 2].is_sorted());
+    assert!([0].is_sorted());
+    assert!(empty.is_sorted());
+    assert!(![0.0, 1.0, std::f32::NAN].is_sorted());
+    assert!([-2, -1, 0, 3].is_sorted());
+    assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
+    assert!(!["c", "bb", "aaa"].is_sorted());
+    assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
+}
diff --git a/src/libcore/tests/time.rs b/src/libcore/tests/time.rs
index 6efd22572dc18..09aae4583482f 100644
--- a/src/libcore/tests/time.rs
+++ b/src/libcore/tests/time.rs
@@ -107,12 +107,14 @@ fn checked_sub() {
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn sub_bad1() {
     let _ = Duration::new(0, 0) - Duration::new(0, 1);
 }
 
 #[test]
 #[should_panic]
+#[cfg(not(miri))] // Miri does not support panics
 fn sub_bad2() {
     let _ = Duration::new(0, 0) - Duration::new(1, 0);
 }
diff --git a/src/libcore/time.rs b/src/libcore/time.rs
index a751965dffab3..ac7e11754aa3a 100644
--- a/src/libcore/time.rs
+++ b/src/libcore/time.rs
@@ -43,7 +43,7 @@ pub const NANOSECOND: Duration = Duration::from_nanos(1);
 /// timeouts.
 ///
 /// Each `Duration` is composed of a whole number of seconds and a fractional part
-/// represented in nanoseconds.  If the underlying system does not support
+/// represented in nanoseconds. If the underlying system does not support
 /// nanosecond-level precision, APIs binding a system timeout will typically round up
 /// the number of nanoseconds.
 ///
@@ -515,7 +515,7 @@ impl Duration {
         }
     }
 
-    /// Multiply `Duration` by `f64`.
+    /// Multiplies `Duration` by `f64`.
     ///
     /// # Panics
     /// This method will panic if result is not finite, negative or overflows `Duration`.
diff --git a/src/libfmt_macros/Cargo.toml b/src/libfmt_macros/Cargo.toml
index b3f4d2deae2fc..50779a2d9ad08 100644
--- a/src/libfmt_macros/Cargo.toml
+++ b/src/libfmt_macros/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "fmt_macros"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "fmt_macros"
diff --git a/src/libfmt_macros/lib.rs b/src/libfmt_macros/lib.rs
index 32ae878909f30..aacd6cec565a5 100644
--- a/src/libfmt_macros/lib.rs
+++ b/src/libfmt_macros/lib.rs
@@ -4,19 +4,20 @@
 //! Parsing does not happen at runtime: structures of `std::fmt::rt` are
 //! generated instead.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        test(attr(deny(warnings))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(nll)]
+#![feature(rustc_private)]
 
-pub use self::Piece::*;
-pub use self::Position::*;
-pub use self::Alignment::*;
-pub use self::Flag::*;
-pub use self::Count::*;
+pub use Piece::*;
+pub use Position::*;
+pub use Alignment::*;
+pub use Flag::*;
+pub use Count::*;
 
 use std::str;
 use std::string;
@@ -72,6 +73,15 @@ pub enum Position<'a> {
     ArgumentNamed(&'a str),
 }
 
+impl Position<'_> {
+    pub fn index(&self) -> Option<usize> {
+        match self {
+            ArgumentIs(i) | ArgumentImplicitlyIs(i) => Some(*i),
+            _ => None,
+        }
+    }
+}
+
 /// Enum of alignments which are supported.
 #[derive(Copy, Clone, PartialEq)]
 pub enum Alignment {
diff --git a/src/libgraphviz/Cargo.toml b/src/libgraphviz/Cargo.toml
index 76ef3a1d188ce..a6a3c1a249d64 100644
--- a/src/libgraphviz/Cargo.toml
+++ b/src/libgraphviz/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "graphviz"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "graphviz"
diff --git a/src/libgraphviz/lib.rs b/src/libgraphviz/lib.rs
index 164dec97b8fdb..489020d4ee778 100644
--- a/src/libgraphviz/lib.rs
+++ b/src/libgraphviz/lib.rs
@@ -271,15 +271,14 @@
 //!
 //! * [DOT language](http://www.graphviz.org/doc/info/lang.html)
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        test(attr(allow(unused_variables), deny(warnings))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(nll)]
-#![feature(str_escape)]
 
-use self::LabelText::*;
+use LabelText::*;
 
 use std::borrow::Cow;
 use std::io::prelude::*;
@@ -393,7 +392,7 @@ impl<'a> Id<'a> {
     /// digit (i.e., the regular expression `[a-zA-Z_][a-zA-Z_0-9]*`).
     ///
     /// (Note: this format is a strict subset of the `ID` format
-    /// defined by the DOT language.  This function may change in the
+    /// defined by the DOT language. This function may change in the
     /// future to accept a broader subset, or the entirety, of DOT's
     /// `ID` format.)
     ///
@@ -530,7 +529,7 @@ impl<'a> LabelText<'a> {
     }
 
     /// Decomposes content into string suitable for making EscStr that
-    /// yields same content as self.  The result obeys the law
+    /// yields same content as self. The result obeys the law
     /// render(`lt`) == render(`EscStr(lt.pre_escaped_content())`) for
     /// all `lt: LabelText`.
     fn pre_escaped_content(self) -> Cow<'a, str> {
@@ -538,7 +537,7 @@ impl<'a> LabelText<'a> {
             EscStr(s) => s,
             LabelStr(s) => {
                 if s.contains('\\') {
-                    (&*s).escape_default().into()
+                    (&*s).escape_default().to_string().into()
                 } else {
                     s
                 }
@@ -548,12 +547,12 @@ impl<'a> LabelText<'a> {
     }
 
     /// Puts `prefix` on a line above this label, with a blank line separator.
-    pub fn prefix_line(self, prefix: LabelText) -> LabelText<'static> {
+    pub fn prefix_line(self, prefix: LabelText<'_>) -> LabelText<'static> {
         prefix.suffix_line(self)
     }
 
     /// Puts `suffix` on a line below this label, with a blank line separator.
-    pub fn suffix_line(self, suffix: LabelText) -> LabelText<'static> {
+    pub fn suffix_line(self, suffix: LabelText<'_>) -> LabelText<'static> {
         let mut prefix = self.pre_escaped_content().into_owned();
         let suffix = suffix.pre_escaped_content();
         prefix.push_str(r"\n\n");
@@ -686,7 +685,7 @@ pub fn render_opts<'a, N, E, G, W>(g: &'a G,
 
 #[cfg(test)]
 mod tests {
-    use self::NodeLabels::*;
+    use NodeLabels::*;
     use super::{Id, Labeller, Nodes, Edges, GraphWalk, render, Style};
     use super::LabelText::{self, LabelStr, EscStr, HtmlStr};
     use std::io;
diff --git a/src/libpanic_abort/Cargo.toml b/src/libpanic_abort/Cargo.toml
index e304e61c32936..2bee0b716c750 100644
--- a/src/libpanic_abort/Cargo.toml
+++ b/src/libpanic_abort/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "panic_abort"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 path = "lib.rs"
diff --git a/src/libpanic_abort/lib.rs b/src/libpanic_abort/lib.rs
index 8832a16d4ca4e..edc97cd28a52a 100644
--- a/src/libpanic_abort/lib.rs
+++ b/src/libpanic_abort/lib.rs
@@ -5,14 +5,13 @@
 
 #![no_std]
 #![unstable(feature = "panic_abort", issue = "32837")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
 #![panic_runtime]
+
 #![allow(unused_features)]
+#![deny(rust_2018_idioms)]
 
-#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(core_intrinsics)]
 #![feature(libc)]
 #![feature(nll)]
@@ -47,7 +46,6 @@ pub unsafe extern fn __rust_start_panic(_payload: usize) -> u32 {
 
     #[cfg(any(unix, target_os = "cloudabi"))]
     unsafe fn abort() -> ! {
-        extern crate libc;
         libc::abort();
     }
 
diff --git a/src/libpanic_unwind/Cargo.toml b/src/libpanic_unwind/Cargo.toml
index c9fce621608a2..1b3901ac11a96 100644
--- a/src/libpanic_unwind/Cargo.toml
+++ b/src/libpanic_unwind/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "panic_unwind"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 path = "lib.rs"
diff --git a/src/libpanic_unwind/dummy.rs b/src/libpanic_unwind/dummy.rs
index b052f76e2a3a8..3a00d6376658c 100644
--- a/src/libpanic_unwind/dummy.rs
+++ b/src/libpanic_unwind/dummy.rs
@@ -1,6 +1,6 @@
-//! Unwinding for wasm32
+//! Unwinding for *wasm32* target.
 //!
-//! Right now we don't support this, so this is just stubs
+//! Right now we don't support this, so this is just stubs.
 
 use alloc::boxed::Box;
 use core::any::Any;
diff --git a/src/libpanic_unwind/dwarf/eh.rs b/src/libpanic_unwind/dwarf/eh.rs
index ce7fab8584a28..07fa2971847f6 100644
--- a/src/libpanic_unwind/dwarf/eh.rs
+++ b/src/libpanic_unwind/dwarf/eh.rs
@@ -6,12 +6,12 @@
 //!   http://www.airs.com/blog/archives/464
 //!
 //! A reference implementation may be found in the GCC source tree
-//! (<root>/libgcc/unwind-c.c as of this writing)
+//! (`<root>/libgcc/unwind-c.c` as of this writing).
 
 #![allow(non_upper_case_globals)]
 #![allow(unused)]
 
-use dwarf::DwarfReader;
+use crate::dwarf::DwarfReader;
 use core::mem;
 
 pub const DW_EH_PE_omit: u8 = 0xFF;
@@ -51,7 +51,7 @@ pub enum EHAction {
 
 pub const USING_SJLJ_EXCEPTIONS: bool = cfg!(all(target_os = "ios", target_arch = "arm"));
 
-pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext)
+pub unsafe fn find_eh_action(lsda: *const u8, context: &EHContext<'_>)
     -> Result<EHAction, ()>
 {
     if lsda.is_null() {
@@ -145,7 +145,7 @@ fn round_up(unrounded: usize, align: usize) -> Result<usize, ()> {
 }
 
 unsafe fn read_encoded_pointer(reader: &mut DwarfReader,
-                               context: &EHContext,
+                               context: &EHContext<'_>,
                                encoding: u8)
                                -> Result<usize, ()> {
     if encoding == DW_EH_PE_omit {
diff --git a/src/libpanic_unwind/dwarf/mod.rs b/src/libpanic_unwind/dwarf/mod.rs
index eb5fb81f61b83..0360696426dc9 100644
--- a/src/libpanic_unwind/dwarf/mod.rs
+++ b/src/libpanic_unwind/dwarf/mod.rs
@@ -1,5 +1,5 @@
 //! Utilities for parsing DWARF-encoded data streams.
-//! See http://www.dwarfstd.org,
+//! See <http://www.dwarfstd.org>,
 //! DWARF-4 standard, Section 7 - "Data Representation"
 
 // This module is used only by x86_64-pc-windows-gnu for now, but we
diff --git a/src/libpanic_unwind/emcc.rs b/src/libpanic_unwind/emcc.rs
index 45c9244a46fcd..18e9006468ef3 100644
--- a/src/libpanic_unwind/emcc.rs
+++ b/src/libpanic_unwind/emcc.rs
@@ -1,19 +1,19 @@
-//! Unwinding for emscripten
+//! Unwinding for *emscripten* target.
 //!
 //! Whereas Rust's usual unwinding implementation for Unix platforms
-//! calls into the libunwind APIs directly, on emscripten we instead
+//! calls into the libunwind APIs directly, on Emscripten we instead
 //! call into the C++ unwinding APIs. This is just an expedience since
-//! emscripten's runtime always implements those APIs and does not
+//! Emscripten's runtime always implements those APIs and does not
 //! implement libunwind.
 
 #![allow(private_no_mangle_fns)]
 
 use core::any::Any;
 use core::ptr;
+use core::mem;
 use alloc::boxed::Box;
 use libc::{self, c_int};
 use unwind as uw;
-use core::mem;
 
 pub fn payload() -> *mut u8 {
     ptr::null_mut()
diff --git a/src/libpanic_unwind/gcc.rs b/src/libpanic_unwind/gcc.rs
index 065403aba1b98..e2b743b379704 100644
--- a/src/libpanic_unwind/gcc.rs
+++ b/src/libpanic_unwind/gcc.rs
@@ -1,4 +1,4 @@
-//! Implementation of panics backed by libgcc/libunwind (in some form)
+//! Implementation of panics backed by libgcc/libunwind (in some form).
 //!
 //! For background on exception handling and stack unwinding please see
 //! "Exception Handling in LLVM" (llvm.org/docs/ExceptionHandling.html) and
@@ -23,14 +23,14 @@
 //!
 //! In the search phase, the job of a personality routine is to examine
 //! exception object being thrown, and to decide whether it should be caught at
-//! that stack frame.  Once the handler frame has been identified, cleanup phase
+//! that stack frame. Once the handler frame has been identified, cleanup phase
 //! begins.
 //!
 //! In the cleanup phase, the unwinder invokes each personality routine again.
 //! This time it decides which (if any) cleanup code needs to be run for
-//! the current stack frame.  If so, the control is transferred to a special
+//! the current stack frame. If so, the control is transferred to a special
 //! branch in the function body, the "landing pad", which invokes destructors,
-//! frees memory, etc.  At the end of the landing pad, control is transferred
+//! frees memory, etc. At the end of the landing pad, control is transferred
 //! back to the unwinder and unwinding resumes.
 //!
 //! Once stack has been unwound down to the handler frame level, unwinding stops
@@ -39,7 +39,7 @@
 //! ## `eh_personality` and `eh_unwind_resume`
 //!
 //! These language items are used by the compiler when generating unwind info.
-//! The first one is the personality routine described above.  The second one
+//! The first one is the personality routine described above. The second one
 //! allows compilation target to customize the process of resuming unwind at the
 //! end of the landing pads. `eh_unwind_resume` is used only if
 //! `custom_unwind_resume` flag in the target options is set.
@@ -52,7 +52,7 @@ use alloc::boxed::Box;
 
 use unwind as uw;
 use libc::{c_int, uintptr_t};
-use dwarf::eh::{self, EHContext, EHAction};
+use crate::dwarf::eh::{self, EHContext, EHAction};
 
 #[repr(C)]
 struct Exception {
diff --git a/src/libpanic_unwind/lib.rs b/src/libpanic_unwind/lib.rs
index 98f174710d243..9d3d8f6185bb3 100644
--- a/src/libpanic_unwind/lib.rs
+++ b/src/libpanic_unwind/lib.rs
@@ -14,11 +14,11 @@
 
 #![no_std]
 #![unstable(feature = "panic_unwind", issue = "32837")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(allocator_api)]
 #![feature(alloc)]
 #![feature(core_intrinsics)]
@@ -34,11 +34,6 @@
 #![panic_runtime]
 #![feature(panic_runtime)]
 
-extern crate alloc;
-extern crate libc;
-#[cfg(not(any(target_env = "msvc", all(windows, target_arch = "x86_64", target_env = "gnu"))))]
-extern crate unwind;
-
 use alloc::boxed::Box;
 use core::intrinsics;
 use core::mem;
@@ -89,7 +84,7 @@ pub unsafe extern "C" fn __rust_maybe_catch_panic(f: fn(*mut u8),
                                                   vtable_ptr: *mut usize)
                                                   -> u32 {
     let mut payload = imp::payload();
-    if intrinsics::try(f, data, &mut payload as *mut _ as *mut _) == 0 {
+    if intrinsics::r#try(f, data, &mut payload as *mut _ as *mut _) == 0 {
         0
     } else {
         let obj = mem::transmute::<_, raw::TraitObject>(imp::cleanup(payload));
diff --git a/src/libpanic_unwind/seh.rs b/src/libpanic_unwind/seh.rs
index f52d010815c5d..996fdb931eff2 100644
--- a/src/libpanic_unwind/seh.rs
+++ b/src/libpanic_unwind/seh.rs
@@ -52,7 +52,7 @@ use core::any::Any;
 use core::mem;
 use core::raw;
 
-use windows as c;
+use crate::windows as c;
 use libc::{c_int, c_uint};
 
 // First up, a whole bunch of type definitions. There's a few platform-specific
@@ -301,5 +301,5 @@ pub unsafe fn cleanup(payload: [u64; 2]) -> Box<dyn Any + Send> {
 #[lang = "eh_personality"]
 #[cfg(not(test))]
 fn rust_eh_personality() {
-    unsafe { ::core::intrinsics::abort() }
+    unsafe { core::intrinsics::abort() }
 }
diff --git a/src/libpanic_unwind/seh64_gnu.rs b/src/libpanic_unwind/seh64_gnu.rs
index 56ff6082190bc..457ffcd34f9c7 100644
--- a/src/libpanic_unwind/seh64_gnu.rs
+++ b/src/libpanic_unwind/seh64_gnu.rs
@@ -9,8 +9,8 @@ use alloc::boxed::Box;
 use core::any::Any;
 use core::intrinsics;
 use core::ptr;
-use dwarf::eh::{EHContext, EHAction, find_eh_action};
-use windows as c;
+use crate::dwarf::eh::{EHContext, EHAction, find_eh_action};
+use crate::windows as c;
 
 // Define our exception codes:
 // according to http://msdn.microsoft.com/en-us/library/het71c37(v=VS.80).aspx,
diff --git a/src/libproc_macro/Cargo.toml b/src/libproc_macro/Cargo.toml
index f903f79f9afc0..b3d0ee94f0e12 100644
--- a/src/libproc_macro/Cargo.toml
+++ b/src/libproc_macro/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "proc_macro"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 path = "lib.rs"
diff --git a/src/libproc_macro/bridge/buffer.rs b/src/libproc_macro/bridge/buffer.rs
index 8bc4f0fec85a8..0d8cc552d61ab 100644
--- a/src/libproc_macro/bridge/buffer.rs
+++ b/src/libproc_macro/bridge/buffer.rs
@@ -6,7 +6,7 @@ use std::ops::{Deref, DerefMut};
 use std::slice;
 
 #[repr(C)]
-struct Slice<'a, T: 'a> {
+struct Slice<'a, T> {
     data: &'a [T; 0],
     len: usize,
 }
@@ -42,7 +42,7 @@ pub struct Buffer<T: Copy> {
     data: *mut T,
     len: usize,
     capacity: usize,
-    extend_from_slice: extern "C" fn(Buffer<T>, Slice<T>) -> Buffer<T>,
+    extend_from_slice: extern "C" fn(Buffer<T>, Slice<'_, T>) -> Buffer<T>,
     drop: extern "C" fn(Buffer<T>),
 }
 
@@ -139,7 +139,7 @@ impl<T: Copy> From<Vec<T>> for Buffer<T> {
             }
         }
 
-        extern "C" fn extend_from_slice<T: Copy>(b: Buffer<T>, xs: Slice<T>) -> Buffer<T> {
+        extern "C" fn extend_from_slice<T: Copy>(b: Buffer<T>, xs: Slice<'_, T>) -> Buffer<T> {
             let mut v = to_vec(b);
             v.extend_from_slice(&xs);
             Buffer::from(v)
diff --git a/src/libproc_macro/bridge/client.rs b/src/libproc_macro/bridge/client.rs
index 3095c8041f2c1..b198bdb144699 100644
--- a/src/libproc_macro/bridge/client.rs
+++ b/src/libproc_macro/bridge/client.rs
@@ -66,7 +66,7 @@ macro_rules! define_handles {
             impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
                 for Marked<S::$oty, $oty>
             {
-                fn decode(r: &mut Reader, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
+                fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
                     s.$oty.take(handle::Handle::decode(r, &mut ()))
                 }
             }
@@ -80,7 +80,7 @@ macro_rules! define_handles {
             impl<S: server::Types> Decode<'_, 's, HandleStore<server::MarkedTypes<S>>>
                 for &'s Marked<S::$oty, $oty>
             {
-                fn decode(r: &mut Reader, s: &'s HandleStore<server::MarkedTypes<S>>) -> Self {
+                fn decode(r: &mut Reader<'_>, s: &'s HandleStore<server::MarkedTypes<S>>) -> Self {
                     &s.$oty[handle::Handle::decode(r, &mut ())]
                 }
             }
@@ -94,7 +94,10 @@ macro_rules! define_handles {
             impl<S: server::Types> DecodeMut<'_, 's, HandleStore<server::MarkedTypes<S>>>
                 for &'s mut Marked<S::$oty, $oty>
             {
-                fn decode(r: &mut Reader, s: &'s mut HandleStore<server::MarkedTypes<S>>) -> Self {
+                fn decode(
+                    r: &mut Reader<'_>,
+                    s: &'s mut HandleStore<server::MarkedTypes<S>>
+                ) -> Self {
                     &mut s.$oty[handle::Handle::decode(r, &mut ())]
                 }
             }
@@ -108,7 +111,7 @@ macro_rules! define_handles {
             }
 
             impl<S> DecodeMut<'_, '_, S> for $oty {
-                fn decode(r: &mut Reader, s: &mut S) -> Self {
+                fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                     $oty(handle::Handle::decode(r, s))
                 }
             }
@@ -130,7 +133,7 @@ macro_rules! define_handles {
             impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
                 for Marked<S::$ity, $ity>
             {
-                fn decode(r: &mut Reader, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
+                fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
                     s.$ity.copy(handle::Handle::decode(r, &mut ()))
                 }
             }
@@ -144,7 +147,7 @@ macro_rules! define_handles {
             }
 
             impl<S> DecodeMut<'_, '_, S> for $ity {
-                fn decode(r: &mut Reader, s: &mut S) -> Self {
+                fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                     $ity(handle::Handle::decode(r, s))
                 }
             }
@@ -200,7 +203,7 @@ impl Clone for Literal {
 
 // FIXME(eddyb) `Literal` should not expose internal `Debug` impls.
 impl fmt::Debug for Literal {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.debug())
     }
 }
@@ -212,7 +215,7 @@ impl Clone for SourceFile {
 }
 
 impl fmt::Debug for Span {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.debug())
     }
 }
@@ -275,7 +278,7 @@ impl BridgeState<'_> {
     ///
     /// N.B., while `f` is running, the thread-local state
     /// is `BridgeState::InUse`.
-    fn with<R>(f: impl FnOnce(&mut BridgeState) -> R) -> R {
+    fn with<R>(f: impl FnOnce(&mut BridgeState<'_>) -> R) -> R {
         BRIDGE_STATE.with(|state| {
             state.replace(BridgeState::InUse, |mut state| {
                 // FIXME(#52812) pass `f` directly to `replace` when `RefMutL` is gone
@@ -306,7 +309,7 @@ impl Bridge<'_> {
         BRIDGE_STATE.with(|state| state.set(BridgeState::Connected(self), f))
     }
 
-    fn with<R>(f: impl FnOnce(&mut Bridge) -> R) -> R {
+    fn with<R>(f: impl FnOnce(&mut Bridge<'_>) -> R) -> R {
         BridgeState::with(|state| match state {
             BridgeState::NotConnected => {
                 panic!("procedural macro API is used outside of a procedural macro");
@@ -331,15 +334,15 @@ impl Bridge<'_> {
 #[derive(Copy, Clone)]
 pub struct Client<F> {
     pub(super) get_handle_counters: extern "C" fn() -> &'static HandleCounters,
-    pub(super) run: extern "C" fn(Bridge, F) -> Buffer<u8>,
+    pub(super) run: extern "C" fn(Bridge<'_>, F) -> Buffer<u8>,
     pub(super) f: F,
 }
 
 // FIXME(#53451) public to work around `Cannot create local mono-item` ICE,
 // affecting not only the function itself, but also the `BridgeState` `thread_local!`.
 pub extern "C" fn __run_expand1(
-    mut bridge: Bridge,
-    f: fn(::TokenStream) -> ::TokenStream,
+    mut bridge: Bridge<'_>,
+    f: fn(crate::TokenStream) -> crate::TokenStream,
 ) -> Buffer<u8> {
     // The initial `cached_buffer` contains the input.
     let mut b = bridge.cached_buffer.take();
@@ -352,7 +355,7 @@ pub extern "C" fn __run_expand1(
             // Put the `cached_buffer` back in the `Bridge`, for requests.
             Bridge::with(|bridge| bridge.cached_buffer = b.take());
 
-            let output = f(::TokenStream(input)).0;
+            let output = f(crate::TokenStream(input)).0;
 
             // Take the `cached_buffer` back out, for the output value.
             b = Bridge::with(|bridge| bridge.cached_buffer.take());
@@ -378,8 +381,8 @@ pub extern "C" fn __run_expand1(
     b
 }
 
-impl Client<fn(::TokenStream) -> ::TokenStream> {
-    pub const fn expand1(f: fn(::TokenStream) -> ::TokenStream) -> Self {
+impl Client<fn(crate::TokenStream) -> crate::TokenStream> {
+    pub const fn expand1(f: fn(crate::TokenStream) -> crate::TokenStream) -> Self {
         Client {
             get_handle_counters: HandleCounters::get,
             run: __run_expand1,
@@ -391,8 +394,8 @@ impl Client<fn(::TokenStream) -> ::TokenStream> {
 // FIXME(#53451) public to work around `Cannot create local mono-item` ICE,
 // affecting not only the function itself, but also the `BridgeState` `thread_local!`.
 pub extern "C" fn __run_expand2(
-    mut bridge: Bridge,
-    f: fn(::TokenStream, ::TokenStream) -> ::TokenStream,
+    mut bridge: Bridge<'_>,
+    f: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream,
 ) -> Buffer<u8> {
     // The initial `cached_buffer` contains the input.
     let mut b = bridge.cached_buffer.take();
@@ -406,7 +409,7 @@ pub extern "C" fn __run_expand2(
             // Put the `cached_buffer` back in the `Bridge`, for requests.
             Bridge::with(|bridge| bridge.cached_buffer = b.take());
 
-            let output = f(::TokenStream(input), ::TokenStream(input2)).0;
+            let output = f(crate::TokenStream(input), crate::TokenStream(input2)).0;
 
             // Take the `cached_buffer` back out, for the output value.
             b = Bridge::with(|bridge| bridge.cached_buffer.take());
@@ -432,8 +435,10 @@ pub extern "C" fn __run_expand2(
     b
 }
 
-impl Client<fn(::TokenStream, ::TokenStream) -> ::TokenStream> {
-    pub const fn expand2(f: fn(::TokenStream, ::TokenStream) -> ::TokenStream) -> Self {
+impl Client<fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream> {
+    pub const fn expand2(
+        f: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream
+    ) -> Self {
         Client {
             get_handle_counters: HandleCounters::get,
             run: __run_expand2,
@@ -448,17 +453,17 @@ pub enum ProcMacro {
     CustomDerive {
         trait_name: &'static str,
         attributes: &'static [&'static str],
-        client: Client<fn(::TokenStream) -> ::TokenStream>,
+        client: Client<fn(crate::TokenStream) -> crate::TokenStream>,
     },
 
     Attr {
         name: &'static str,
-        client: Client<fn(::TokenStream, ::TokenStream) -> ::TokenStream>,
+        client: Client<fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream>,
     },
 
     Bang {
         name: &'static str,
-        client: Client<fn(::TokenStream) -> ::TokenStream>,
+        client: Client<fn(crate::TokenStream) -> crate::TokenStream>,
     },
 }
 
@@ -466,7 +471,7 @@ impl ProcMacro {
     pub const fn custom_derive(
         trait_name: &'static str,
         attributes: &'static [&'static str],
-        expand: fn(::TokenStream) -> ::TokenStream,
+        expand: fn(crate::TokenStream) -> crate::TokenStream,
     ) -> Self {
         ProcMacro::CustomDerive {
             trait_name,
@@ -477,7 +482,7 @@ impl ProcMacro {
 
     pub const fn attr(
         name: &'static str,
-        expand: fn(::TokenStream, ::TokenStream) -> ::TokenStream,
+        expand: fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream,
     ) -> Self {
         ProcMacro::Attr {
             name,
@@ -485,7 +490,10 @@ impl ProcMacro {
         }
     }
 
-    pub const fn bang(name: &'static str, expand: fn(::TokenStream) -> ::TokenStream) -> Self {
+    pub const fn bang(
+        name: &'static str,
+        expand: fn(crate::TokenStream) -> crate::TokenStream
+    ) -> Self {
         ProcMacro::Bang {
             name,
             client: Client::expand1(expand),
diff --git a/src/libproc_macro/bridge/mod.rs b/src/libproc_macro/bridge/mod.rs
index 6c3e534bf9197..3173651b03951 100644
--- a/src/libproc_macro/bridge/mod.rs
+++ b/src/libproc_macro/bridge/mod.rs
@@ -17,7 +17,7 @@ use std::panic;
 use std::sync::atomic::AtomicUsize;
 use std::sync::Once;
 use std::thread;
-use {Delimiter, Level, LineColumn, Spacing};
+use crate::{Delimiter, Level, LineColumn, Spacing};
 
 /// Higher-order macro describing the server RPC API, allowing automatic
 /// generation of type-safe Rust APIs, both client-side and server-side.
@@ -196,9 +196,9 @@ mod scoped_cell;
 #[forbid(unsafe_code)]
 pub mod server;
 
-use self::buffer::Buffer;
-pub use self::rpc::PanicMessage;
-use self::rpc::{Decode, DecodeMut, Encode, Reader, Writer};
+use buffer::Buffer;
+pub use rpc::PanicMessage;
+use rpc::{Decode, DecodeMut, Encode, Reader, Writer};
 
 /// An active connection between a server and a client.
 /// The server creates the bridge (`Bridge::run_server` in `server.rs`),
diff --git a/src/libproc_macro/bridge/rpc.rs b/src/libproc_macro/bridge/rpc.rs
index 74ae711a47372..a3bc0d2290846 100644
--- a/src/libproc_macro/bridge/rpc.rs
+++ b/src/libproc_macro/bridge/rpc.rs
@@ -40,7 +40,7 @@ macro_rules! rpc_encode_decode {
         }
 
         impl<S> DecodeMut<'_, '_, S> for $ty {
-            fn decode(r: &mut Reader, s: &mut S) -> Self {
+            fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                 let mut byte = 0x80;
                 let mut v = 0;
                 let mut shift = 0;
@@ -61,7 +61,7 @@ macro_rules! rpc_encode_decode {
         }
 
         impl<S> DecodeMut<'_, '_, S> for $name {
-            fn decode(r: &mut Reader, s: &mut S) -> Self {
+            fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
                 $name {
                     $($field: DecodeMut::decode(r, s)),*
                 }
@@ -119,7 +119,7 @@ impl<S> Encode<S> for () {
 }
 
 impl<S> DecodeMut<'_, '_, S> for () {
-    fn decode(_: &mut Reader, _: &mut S) -> Self {}
+    fn decode(_: &mut Reader<'_>, _: &mut S) -> Self {}
 }
 
 impl<S> Encode<S> for u8 {
@@ -129,7 +129,7 @@ impl<S> Encode<S> for u8 {
 }
 
 impl<S> DecodeMut<'_, '_, S> for u8 {
-    fn decode(r: &mut Reader, _: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, _: &mut S) -> Self {
         let x = r[0];
         *r = &r[1..];
         x
@@ -146,7 +146,7 @@ impl<S> Encode<S> for bool {
 }
 
 impl<S> DecodeMut<'_, '_, S> for bool {
-    fn decode(r: &mut Reader, s: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         match u8::decode(r, s) {
             0 => false,
             1 => true,
@@ -162,7 +162,7 @@ impl<S> Encode<S> for char {
 }
 
 impl<S> DecodeMut<'_, '_, S> for char {
-    fn decode(r: &mut Reader, s: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         char::from_u32(u32::decode(r, s)).unwrap()
     }
 }
@@ -174,7 +174,7 @@ impl<S> Encode<S> for NonZeroU32 {
 }
 
 impl<S> DecodeMut<'_, '_, S> for NonZeroU32 {
-    fn decode(r: &mut Reader, s: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         Self::new(u32::decode(r, s)).unwrap()
     }
 }
@@ -251,7 +251,7 @@ impl<S> Encode<S> for String {
 }
 
 impl<S> DecodeMut<'_, '_, S> for String {
-    fn decode(r: &mut Reader, s: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         <&str>::decode(r, s).to_string()
     }
 }
@@ -306,7 +306,7 @@ impl<S> Encode<S> for PanicMessage {
 }
 
 impl<S> DecodeMut<'_, '_, S> for PanicMessage {
-    fn decode(r: &mut Reader, s: &mut S) -> Self {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
         match Option::<String>::decode(r, s) {
             Some(s) => PanicMessage::String(s),
             None => PanicMessage::Unknown,
diff --git a/src/libproc_macro/bridge/scoped_cell.rs b/src/libproc_macro/bridge/scoped_cell.rs
index b1ab27c153e06..6f7965095b638 100644
--- a/src/libproc_macro/bridge/scoped_cell.rs
+++ b/src/libproc_macro/bridge/scoped_cell.rs
@@ -38,7 +38,7 @@ impl<T: LambdaL> ScopedCell<T> {
         ScopedCell(Cell::new(value))
     }
 
-    /// Set the value in `self` to `replacement` while
+    /// Sets the value in `self` to `replacement` while
     /// running `f`, which gets the old value, mutably.
     /// The old value will be restored after `f` exits, even
     /// by panic, including modifications made to it by `f`.
@@ -73,7 +73,7 @@ impl<T: LambdaL> ScopedCell<T> {
         f(RefMutL(put_back_on_drop.value.as_mut().unwrap()))
     }
 
-    /// Set the value in `self` to `value` while running `f`.
+    /// Sets the value in `self` to `value` while running `f`.
     pub fn set<'a, R>(&self, value: <T as ApplyL<'a>>::Out, f: impl FnOnce() -> R) -> R {
         self.replace(value, |_| f())
     }
diff --git a/src/libproc_macro/bridge/server.rs b/src/libproc_macro/bridge/server.rs
index 9a7cb1318dbe4..75806eb9d1760 100644
--- a/src/libproc_macro/bridge/server.rs
+++ b/src/libproc_macro/bridge/server.rs
@@ -131,7 +131,7 @@ pub trait ExecutionStrategy {
         &self,
         dispatcher: &mut impl DispatcherTrait,
         input: Buffer<u8>,
-        run_client: extern "C" fn(Bridge, D) -> Buffer<u8>,
+        run_client: extern "C" fn(Bridge<'_>, D) -> Buffer<u8>,
         client_data: D,
     ) -> Buffer<u8>;
 }
@@ -143,7 +143,7 @@ impl ExecutionStrategy for SameThread {
         &self,
         dispatcher: &mut impl DispatcherTrait,
         input: Buffer<u8>,
-        run_client: extern "C" fn(Bridge, D) -> Buffer<u8>,
+        run_client: extern "C" fn(Bridge<'_>, D) -> Buffer<u8>,
         client_data: D,
     ) -> Buffer<u8> {
         let mut dispatch = |b| dispatcher.dispatch(b);
@@ -168,7 +168,7 @@ impl ExecutionStrategy for CrossThread1 {
         &self,
         dispatcher: &mut impl DispatcherTrait,
         input: Buffer<u8>,
-        run_client: extern "C" fn(Bridge, D) -> Buffer<u8>,
+        run_client: extern "C" fn(Bridge<'_>, D) -> Buffer<u8>,
         client_data: D,
     ) -> Buffer<u8> {
         use std::sync::mpsc::channel;
@@ -206,7 +206,7 @@ impl ExecutionStrategy for CrossThread2 {
         &self,
         dispatcher: &mut impl DispatcherTrait,
         input: Buffer<u8>,
-        run_client: extern "C" fn(Bridge, D) -> Buffer<u8>,
+        run_client: extern "C" fn(Bridge<'_>, D) -> Buffer<u8>,
         client_data: D,
     ) -> Buffer<u8> {
         use std::sync::{Arc, Mutex};
@@ -273,7 +273,7 @@ fn run_server<
     handle_counters: &'static client::HandleCounters,
     server: S,
     input: I,
-    run_client: extern "C" fn(Bridge, D) -> Buffer<u8>,
+    run_client: extern "C" fn(Bridge<'_>, D) -> Buffer<u8>,
     client_data: D,
 ) -> Result<O, PanicMessage> {
     let mut dispatcher = Dispatcher {
@@ -289,7 +289,7 @@ fn run_server<
     Result::decode(&mut &b[..], &mut dispatcher.handle_store)
 }
 
-impl client::Client<fn(::TokenStream) -> ::TokenStream> {
+impl client::Client<fn(crate::TokenStream) -> crate::TokenStream> {
     pub fn run<S: Server>(
         &self,
         strategy: &impl ExecutionStrategy,
@@ -313,7 +313,7 @@ impl client::Client<fn(::TokenStream) -> ::TokenStream> {
     }
 }
 
-impl client::Client<fn(::TokenStream, ::TokenStream) -> ::TokenStream> {
+impl client::Client<fn(crate::TokenStream, crate::TokenStream) -> crate::TokenStream> {
     pub fn run<S: Server>(
         &self,
         strategy: &impl ExecutionStrategy,
diff --git a/src/libproc_macro/diagnostic.rs b/src/libproc_macro/diagnostic.rs
index 64d0c3893c730..65eebb5ec3737 100644
--- a/src/libproc_macro/diagnostic.rs
+++ b/src/libproc_macro/diagnostic.rs
@@ -1,4 +1,4 @@
-use Span;
+use crate::Span;
 
 /// An enum representing a diagnostic level.
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
@@ -56,7 +56,7 @@ pub struct Diagnostic {
 
 macro_rules! diagnostic_child_methods {
     ($spanned:ident, $regular:ident, $level:expr) => (
-        /// Add a new child diagnostic message to `self` with the level
+        /// Adds a new child diagnostic message to `self` with the level
         /// identified by this method's name with the given `spans` and
         /// `message`.
         #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
@@ -67,7 +67,7 @@ macro_rules! diagnostic_child_methods {
             self
         }
 
-        /// Add a new child diagnostic message to `self` with the level
+        /// Adds a new child diagnostic message to `self` with the level
         /// identified by this method's name with the given `message`.
         #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
         pub fn $regular<T: Into<String>>(mut self, message: T) -> Diagnostic {
@@ -80,7 +80,7 @@ macro_rules! diagnostic_child_methods {
 /// Iterator over the children diagnostics of a `Diagnostic`.
 #[derive(Debug, Clone)]
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
-pub struct Children<'a>(::std::slice::Iter<'a, Diagnostic>);
+pub struct Children<'a>(std::slice::Iter<'a, Diagnostic>);
 
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
 impl<'a> Iterator for Children<'a> {
@@ -93,7 +93,7 @@ impl<'a> Iterator for Children<'a> {
 
 #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
 impl Diagnostic {
-    /// Create a new diagnostic with the given `level` and `message`.
+    /// Creates a new diagnostic with the given `level` and `message`.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
     pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
         Diagnostic {
@@ -104,7 +104,7 @@ impl Diagnostic {
         }
     }
 
-    /// Create a new diagnostic with the given `level` and `message` pointing to
+    /// Creates a new diagnostic with the given `level` and `message` pointing to
     /// the given set of `spans`.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
     pub fn spanned<S, T>(spans: S, level: Level, message: T) -> Diagnostic
@@ -161,22 +161,22 @@ impl Diagnostic {
 
     /// Returns an iterator over the children diagnostics of `self`.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
-    pub fn children(&self) -> Children {
+    pub fn children(&self) -> Children<'_> {
         Children(self.children.iter())
     }
 
     /// Emit the diagnostic.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
     pub fn emit(self) {
-        fn to_internal(spans: Vec<Span>) -> ::bridge::client::MultiSpan {
-            let mut multi_span = ::bridge::client::MultiSpan::new();
+        fn to_internal(spans: Vec<Span>) -> crate::bridge::client::MultiSpan {
+            let mut multi_span = crate::bridge::client::MultiSpan::new();
             for span in spans {
                 multi_span.push(span.0);
             }
             multi_span
         }
 
-        let mut diag = ::bridge::client::Diagnostic::new(
+        let mut diag = crate::bridge::client::Diagnostic::new(
             self.level,
             &self.message[..],
             to_internal(self.spans),
diff --git a/src/libproc_macro/lib.rs b/src/libproc_macro/lib.rs
index 868190d01057d..6c061189d00d7 100644
--- a/src/libproc_macro/lib.rs
+++ b/src/libproc_macro/lib.rs
@@ -5,18 +5,20 @@
 //! function-like macros `#[proc_macro]`, macro attributes `#[proc_macro_attribute]` and
 //! custom derive attributes`#[proc_macro_derive]`.
 //!
-//! See [the book](../book/first-edition/procedural-macros.html) for more.
+//! See [the book] for more.
+//!
+//! [the book]: ../book/ch19-06-macros.html#procedural-macros-for-generating-code-from-attributes
 
 #![stable(feature = "proc_macro_lib", since = "1.15.0")]
 #![deny(missing_docs)]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject, attr(deny(warnings))),
        test(attr(allow(dead_code, deprecated, unused_variables, unused_mut))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(nll)]
 #![feature(staged_api)]
 #![feature(const_fn)]
@@ -89,7 +91,7 @@ impl TokenStream {
 /// or characters not existing in the language.
 /// All tokens in the parsed stream get `Span::call_site()` spans.
 ///
-/// NOTE: Some errors may cause panics instead of returning `LexError`. We reserve the right to
+/// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
 /// change these errors into `LexError`s later.
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
 impl FromStr for TokenStream {
@@ -114,7 +116,7 @@ impl ToString for TokenStream {
 /// with `Delimiter::None` delimiters and negative numeric literals.
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
 impl fmt::Display for TokenStream {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
@@ -122,7 +124,7 @@ impl fmt::Display for TokenStream {
 /// Prints token in a form convenient for debugging.
 #[stable(feature = "proc_macro_lib", since = "1.15.0")]
 impl fmt::Debug for TokenStream {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str("TokenStream ")?;
         f.debug_list().entries(self.clone()).finish()
     }
@@ -183,7 +185,7 @@ impl Extend<TokenStream> for TokenStream {
 /// Public implementation details for the `TokenStream` type, such as iterators.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 pub mod token_stream {
-    use {bridge, Group, Ident, Literal, Punct, TokenTree, TokenStream};
+    use crate::{bridge, Group, Ident, Literal, Punct, TokenTree, TokenStream};
 
     /// An iterator over `TokenStream`'s `TokenTree`s.
     /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
@@ -245,7 +247,7 @@ impl !Sync for Span {}
 
 macro_rules! diagnostic_method {
     ($name:ident, $level:expr) => (
-        /// Create a new `Diagnostic` with the given `message` at the span
+        /// Creates a new `Diagnostic` with the given `message` at the span
         /// `self`.
         #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
         pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
@@ -291,19 +293,19 @@ impl Span {
         Span(self.0.source())
     }
 
-    /// Get the starting line/column in the source file for this span.
+    /// Gets the starting line/column in the source file for this span.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
     pub fn start(&self) -> LineColumn {
         self.0.start()
     }
 
-    /// Get the ending line/column in the source file for this span.
+    /// Gets the ending line/column in the source file for this span.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
     pub fn end(&self) -> LineColumn {
         self.0.end()
     }
 
-    /// Create a new span encompassing `self` and `other`.
+    /// Creates a new span encompassing `self` and `other`.
     ///
     /// Returns `None` if `self` and `other` are from different files.
     #[unstable(feature = "proc_macro_span", issue = "54725")]
@@ -340,7 +342,7 @@ impl Span {
 /// Prints a span in a form convenient for debugging.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for Span {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.0.fmt(f)
     }
 }
@@ -369,7 +371,7 @@ impl !Sync for LineColumn {}
 pub struct SourceFile(bridge::client::SourceFile);
 
 impl SourceFile {
-    /// Get the path to this source file.
+    /// Gets the path to this source file.
     ///
     /// ### Note
     /// If the code span associated with this `SourceFile` was generated by an external macro, this
@@ -398,7 +400,7 @@ impl SourceFile {
 
 #[unstable(feature = "proc_macro_span", issue = "54725")]
 impl fmt::Debug for SourceFile {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("SourceFile")
             .field("path", &self.path())
             .field("is_real", &self.is_real())
@@ -483,7 +485,7 @@ impl TokenTree {
 /// Prints token tree in a form convenient for debugging.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for TokenTree {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // Each of these has the name in the struct type in the derived debug,
         // so don't bother with an extra layer of indirection
         match *self {
@@ -542,7 +544,7 @@ impl ToString for TokenTree {
 /// with `Delimiter::None` delimiters and negative numeric literals.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for TokenTree {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
@@ -667,14 +669,14 @@ impl ToString for Group {
 /// with `Delimiter::None` delimiters.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Group {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for Group {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Group")
             .field("delimiter", &self.delimiter())
             .field("stream", &self.stream())
@@ -763,14 +765,14 @@ impl ToString for Punct {
 /// back into the same character.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Punct {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for Punct {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Punct")
             .field("ch", &self.as_char())
             .field("spacing", &self.spacing())
@@ -842,14 +844,14 @@ impl ToString for Ident {
 /// back into the same identifier.
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Ident {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for Ident {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Ident")
             .field("ident", &self.to_string())
             .field("span", &self.span())
@@ -1092,14 +1094,14 @@ impl ToString for Literal {
 /// back into the same literal (except for possible rounding for floating point literals).
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Display for Literal {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&self.to_string())
     }
 }
 
 #[stable(feature = "proc_macro_lib2", since = "1.29.0")]
 impl fmt::Debug for Literal {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // FIXME(eddyb) `Literal` should not expose internal `Debug` impls.
         self.0.fmt(f)
     }
diff --git a/src/libproc_macro/quote.rs b/src/libproc_macro/quote.rs
index bd7e96210a950..e3d31b78f4a09 100644
--- a/src/libproc_macro/quote.rs
+++ b/src/libproc_macro/quote.rs
@@ -4,7 +4,7 @@
 //! This quasiquoter uses macros 2.0 hygiene to reliably access
 //! items from `proc_macro`, to build a `proc_macro::TokenStream`.
 
-use {Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
+use crate::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
 
 macro_rules! quote_tt {
     (($($t:tt)*)) => { Group::new(Delimiter::Parenthesis, quote!($($t)*)) };
@@ -63,7 +63,7 @@ macro_rules! quote {
 #[unstable(feature = "proc_macro_quote", issue = "54722")]
 pub fn quote(stream: TokenStream) -> TokenStream {
     if stream.is_empty() {
-        return quote!(::TokenStream::new());
+        return quote!(crate::TokenStream::new());
     }
     let mut after_dollar = false;
     let tokens = stream
@@ -73,7 +73,7 @@ pub fn quote(stream: TokenStream) -> TokenStream {
                 after_dollar = false;
                 match tree {
                     TokenTree::Ident(_) => {
-                        return Some(quote!(Into::<::TokenStream>::into(
+                        return Some(quote!(Into::<crate::TokenStream>::into(
                         Clone::clone(&(@ tree))),));
                     }
                     TokenTree::Punct(ref tt) if tt.as_char() == '$' => {}
@@ -86,33 +86,33 @@ pub fn quote(stream: TokenStream) -> TokenStream {
                 }
             }
 
-            Some(quote!(::TokenStream::from((@ match tree {
-                TokenTree::Punct(tt) => quote!(::TokenTree::Punct(::Punct::new(
+            Some(quote!(crate::TokenStream::from((@ match tree {
+                TokenTree::Punct(tt) => quote!(crate::TokenTree::Punct(crate::Punct::new(
                     (@ TokenTree::from(Literal::character(tt.as_char()))),
                     (@ match tt.spacing() {
-                        Spacing::Alone => quote!(::Spacing::Alone),
-                        Spacing::Joint => quote!(::Spacing::Joint),
+                        Spacing::Alone => quote!(crate::Spacing::Alone),
+                        Spacing::Joint => quote!(crate::Spacing::Joint),
                     }),
                 ))),
-                TokenTree::Group(tt) => quote!(::TokenTree::Group(::Group::new(
+                TokenTree::Group(tt) => quote!(crate::TokenTree::Group(crate::Group::new(
                     (@ match tt.delimiter() {
-                        Delimiter::Parenthesis => quote!(::Delimiter::Parenthesis),
-                        Delimiter::Brace => quote!(::Delimiter::Brace),
-                        Delimiter::Bracket => quote!(::Delimiter::Bracket),
-                        Delimiter::None => quote!(::Delimiter::None),
+                        Delimiter::Parenthesis => quote!(crate::Delimiter::Parenthesis),
+                        Delimiter::Brace => quote!(crate::Delimiter::Brace),
+                        Delimiter::Bracket => quote!(crate::Delimiter::Bracket),
+                        Delimiter::None => quote!(crate::Delimiter::None),
                     }),
                     (@ quote(tt.stream())),
                 ))),
-                TokenTree::Ident(tt) => quote!(::TokenTree::Ident(::Ident::new(
+                TokenTree::Ident(tt) => quote!(crate::TokenTree::Ident(crate::Ident::new(
                     (@ TokenTree::from(Literal::string(&tt.to_string()))),
                     (@ quote_span(tt.span())),
                 ))),
-                TokenTree::Literal(tt) => quote!(::TokenTree::Literal({
+                TokenTree::Literal(tt) => quote!(crate::TokenTree::Literal({
                     let mut iter = (@ TokenTree::from(Literal::string(&tt.to_string())))
-                        .parse::<::TokenStream>()
+                        .parse::<crate::TokenStream>()
                         .unwrap()
                         .into_iter();
-                    if let (Some(::TokenTree::Literal(mut lit)), None) =
+                    if let (Some(crate::TokenTree::Literal(mut lit)), None) =
                         (iter.next(), iter.next())
                     {
                         lit.set_span((@ quote_span(tt.span())));
@@ -129,12 +129,12 @@ pub fn quote(stream: TokenStream) -> TokenStream {
         panic!("unexpected trailing `$` in `quote!`");
     }
 
-    quote!([(@ tokens)].iter().cloned().collect::<::TokenStream>())
+    quote!([(@ tokens)].iter().cloned().collect::<crate::TokenStream>())
 }
 
 /// Quote a `Span` into a `TokenStream`.
 /// This is needed to implement a custom quoter.
 #[unstable(feature = "proc_macro_quote", issue = "54722")]
 pub fn quote_span(_: Span) -> TokenStream {
-    quote!(::Span::def_site())
+    quote!(crate::Span::def_site())
 }
diff --git a/src/libprofiler_builtins/Cargo.toml b/src/libprofiler_builtins/Cargo.toml
index 7c95cf0a0542a..0d36bd0b39d76 100644
--- a/src/libprofiler_builtins/Cargo.toml
+++ b/src/libprofiler_builtins/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 build = "build.rs"
 name = "profiler_builtins"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "profiler_builtins"
diff --git a/src/libprofiler_builtins/build.rs b/src/libprofiler_builtins/build.rs
index b66cd66448748..ff52a03d9dd97 100644
--- a/src/libprofiler_builtins/build.rs
+++ b/src/libprofiler_builtins/build.rs
@@ -2,8 +2,6 @@
 //!
 //! See the build.rs for libcompiler_builtins crate for details.
 
-extern crate cc;
-
 use std::env;
 use std::path::Path;
 
diff --git a/src/libprofiler_builtins/lib.rs b/src/libprofiler_builtins/lib.rs
index 0d12ba01c87a2..2ce1a110b44c0 100644
--- a/src/libprofiler_builtins/lib.rs
+++ b/src/libprofiler_builtins/lib.rs
@@ -7,3 +7,4 @@
 #![allow(unused_features)]
 #![feature(nll)]
 #![feature(staged_api)]
+#![deny(rust_2018_idioms)]
diff --git a/src/librustc/Cargo.toml b/src/librustc/Cargo.toml
index 504e016e5b803..cb9eb32f8d21f 100644
--- a/src/librustc/Cargo.toml
+++ b/src/librustc/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc"
@@ -15,6 +16,7 @@ fmt_macros = { path = "../libfmt_macros" }
 graphviz = { path = "../libgraphviz" }
 jobserver = "0.1"
 lazy_static = "1.0.0"
+num_cpus = "1.0"
 scoped-tls = { version = "0.1.1", features = ["nightly"] }
 log = { version = "0.4", features = ["release_max_level_info", "std"] }
 polonius-engine = "0.6.2"
@@ -23,7 +25,7 @@ rustc-rayon-core = "0.1.1"
 rustc_apfloat = { path = "../librustc_apfloat" }
 rustc_target = { path = "../librustc_target" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc/cfg/construct.rs b/src/librustc/cfg/construct.rs
index 978d20ea94789..9eeae6eeb5f34 100644
--- a/src/librustc/cfg/construct.rs
+++ b/src/librustc/cfg/construct.rs
@@ -1,11 +1,11 @@
-use cfg::*;
-use middle::region;
+use crate::cfg::*;
+use crate::middle::region;
 use rustc_data_structures::graph::implementation as graph;
 use syntax::ptr::P;
-use ty::{self, TyCtxt};
+use crate::ty::{self, TyCtxt};
 
-use hir::{self, PatKind};
-use hir::def_id::DefId;
+use crate::hir::{self, PatKind};
+use crate::hir::def_id::DefId;
 
 struct CFGBuilder<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -99,30 +99,20 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
     }
 
     fn stmt(&mut self, stmt: &hir::Stmt, pred: CFGIndex) -> CFGIndex {
-        let hir_id = self.tcx.hir().node_to_hir_id(stmt.node.id());
-        match stmt.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                let exit = self.decl(&decl, pred);
-                self.add_ast_node(hir_id.local_id, &[exit])
-            }
-
-            hir::StmtKind::Expr(ref expr, _) |
-            hir::StmtKind::Semi(ref expr, _) => {
-                let exit = self.expr(&expr, pred);
-                self.add_ast_node(hir_id.local_id, &[exit])
-            }
-        }
-    }
-
-    fn decl(&mut self, decl: &hir::Decl, pred: CFGIndex) -> CFGIndex {
-        match decl.node {
-            hir::DeclKind::Local(ref local) => {
+        let exit = match stmt.node {
+            hir::StmtKind::Local(ref local) => {
                 let init_exit = self.opt_expr(&local.init, pred);
                 self.pat(&local.pat, init_exit)
             }
-
-            hir::DeclKind::Item(_) => pred,
-        }
+            hir::StmtKind::Item(_) => {
+                pred
+            }
+            hir::StmtKind::Expr(ref expr) |
+            hir::StmtKind::Semi(ref expr) => {
+                self.expr(&expr, pred)
+            }
+        };
+        self.add_ast_node(stmt.hir_id.local_id, &[exit])
     }
 
     fn pat(&mut self, pat: &hir::Pat, pred: CFGIndex) -> CFGIndex {
@@ -160,9 +150,11 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
         }
     }
 
-    fn pats_all<'b, I: Iterator<Item=&'b P<hir::Pat>>>(&mut self,
-                                          pats: I,
-                                          pred: CFGIndex) -> CFGIndex {
+    fn pats_all<'b, I: Iterator<Item=&'b P<hir::Pat>>>(
+        &mut self,
+        pats: I,
+        pred: CFGIndex
+    ) -> CFGIndex {
         //! Handles case where all of the patterns must match.
         pats.fold(pred, |pred, pat| self.pat(&pat, pred))
     }
diff --git a/src/librustc/cfg/graphviz.rs b/src/librustc/cfg/graphviz.rs
index 6dec421760899..969c38bd66329 100644
--- a/src/librustc/cfg/graphviz.rs
+++ b/src/librustc/cfg/graphviz.rs
@@ -4,9 +4,9 @@
 // For clarity, rename the graphviz crate locally to dot.
 use graphviz as dot;
 
-use cfg;
-use hir;
-use ty::TyCtxt;
+use crate::cfg;
+use crate::hir;
+use crate::ty::TyCtxt;
 
 pub type Node<'a> = (cfg::CFGIndex, &'a cfg::CFGNode);
 pub type Edge<'a> = &'a cfg::CFGEdge;
diff --git a/src/librustc/cfg/mod.rs b/src/librustc/cfg/mod.rs
index e58557839f9b9..345dff88b5f0b 100644
--- a/src/librustc/cfg/mod.rs
+++ b/src/librustc/cfg/mod.rs
@@ -2,9 +2,9 @@
 //! Uses `Graph` as the underlying representation.
 
 use rustc_data_structures::graph::implementation as graph;
-use ty::TyCtxt;
-use hir;
-use hir::def_id::DefId;
+use crate::ty::TyCtxt;
+use crate::hir;
+use crate::hir::def_id::DefId;
 
 mod construct;
 pub mod graphviz;
diff --git a/src/librustc/dep_graph/cgu_reuse_tracker.rs b/src/librustc/dep_graph/cgu_reuse_tracker.rs
index e8d1b71048705..13f6f95332973 100644
--- a/src/librustc/dep_graph/cgu_reuse_tracker.rs
+++ b/src/librustc/dep_graph/cgu_reuse_tracker.rs
@@ -2,7 +2,7 @@
 //! compilation. This is used for incremental compilation tests and debug
 //! output.
 
-use session::Session;
+use crate::session::Session;
 use rustc_data_structures::fx::FxHashMap;
 use std::sync::{Arc, Mutex};
 use syntax_pos::Span;
diff --git a/src/librustc/dep_graph/debug.rs b/src/librustc/dep_graph/debug.rs
index a9ad22c5e913e..f18ee3dced72d 100644
--- a/src/librustc/dep_graph/debug.rs
+++ b/src/librustc/dep_graph/debug.rs
@@ -22,7 +22,7 @@ impl DepNodeFilter {
         }
     }
 
-    /// True if all nodes always pass the filter.
+    /// Returns `true` if all nodes always pass the filter.
     pub fn accepts_all(&self) -> bool {
         self.text.is_empty()
     }
diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 427fe51e6ff9c..796739c872174 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -49,25 +49,25 @@
 //! user of the `DepNode` API of having to know how to compute the expected
 //! fingerprint for a given set of node parameters.
 
-use mir::interpret::GlobalId;
-use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX};
-use hir::map::DefPathHash;
-use hir::HirId;
+use crate::mir::interpret::GlobalId;
+use crate::hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX};
+use crate::hir::map::DefPathHash;
+use crate::hir::HirId;
 
-use ich::{Fingerprint, StableHashingContext};
+use crate::ich::{Fingerprint, StableHashingContext};
 use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
 use std::fmt;
 use std::hash::Hash;
 use syntax_pos::symbol::InternedString;
-use traits;
-use traits::query::{
+use crate::traits;
+use crate::traits::query::{
     CanonicalProjectionGoal, CanonicalTyGoal, CanonicalTypeOpAscribeUserTypeGoal,
     CanonicalTypeOpEqGoal, CanonicalTypeOpSubtypeGoal, CanonicalPredicateGoal,
     CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpNormalizeGoal,
 };
-use ty::{TyCtxt, FnSig, Instance, InstanceDef,
+use crate::ty::{TyCtxt, FnSig, Instance, InstanceDef,
          ParamEnv, ParamEnvAnd, Predicate, PolyFnSig, PolyTraitRef, Ty};
-use ty::subst::Substs;
+use crate::ty::subst::Substs;
 
 // erase!() just makes tokens go away. It's used to specify which macro argument
 // is repeated (i.e., which sub-expression of the macro we are in) but don't need
@@ -302,7 +302,7 @@ macro_rules! define_dep_nodes {
                 }
             }
 
-            /// Create a new, parameterless DepNode. This method will assert
+            /// Creates a new, parameterless DepNode. This method will assert
             /// that the DepNode corresponding to the given DepKind actually
             /// does not require any parameters.
             #[inline(always)]
@@ -314,7 +314,7 @@ macro_rules! define_dep_nodes {
                 }
             }
 
-            /// Extract the DefId corresponding to this DepNode. This will work
+            /// Extracts the DefId corresponding to this DepNode. This will work
             /// if two conditions are met:
             ///
             /// 1. The Fingerprint of the DepNode actually is a DefPathHash, and
@@ -389,7 +389,7 @@ impl fmt::Debug for DepNode {
 
         write!(f, "(")?;
 
-        ::ty::tls::with_opt(|opt_tcx| {
+        crate::ty::tls::with_opt(|opt_tcx| {
             if let Some(tcx) = opt_tcx {
                 if let Some(def_id) = self.extract_def_id(tcx) {
                     write!(f, "{}", tcx.def_path_debug_str(def_id))?;
@@ -476,6 +476,10 @@ define_dep_nodes!( <'tcx>
     [] CheckModLoops(DefId),
     [] CheckModUnstableApiUsage(DefId),
     [] CheckModItemTypes(DefId),
+    [] CheckModPrivacy(DefId),
+    [] CheckModIntrinsics(DefId),
+    [] CheckModLiveness(DefId),
+    [] CheckModImplWf(DefId),
     [] CollectModItemTypes(DefId),
 
     [] Reachability,
@@ -583,6 +587,7 @@ define_dep_nodes!( <'tcx>
     [] CheckImplItemWellFormed(DefId),
     [] ReachableNonGenerics(CrateNum),
     [] NativeLibraries(CrateNum),
+    [] EntryFn(CrateNum),
     [] PluginRegistrarFn(CrateNum),
     [] ProcMacroDeclsStatic(CrateNum),
     [input] CrateDisambiguator(CrateNum),
@@ -630,6 +635,7 @@ define_dep_nodes!( <'tcx>
     [input] Freevars(DefId),
     [input] MaybeUnusedTraitImport(DefId),
     [input] MaybeUnusedExternCrates,
+    [input] NamesImportedByGlobUse(DefId),
     [eval_always] StabilityIndex,
     [eval_always] AllTraits,
     [input] AllCrateNums,
@@ -637,6 +643,7 @@ define_dep_nodes!( <'tcx>
     [eval_always] CollectAndPartitionMonoItems,
     [] IsCodegenedItem(DefId),
     [] CodegenUnit(InternedString),
+    [] BackendOptimizationLevel(CrateNum),
     [] CompileCodegenUnit(InternedString),
     [input] OutputFilenames,
     [] NormalizeProjectionTy(CanonicalProjectionGoal<'tcx>),
@@ -791,7 +798,7 @@ impl<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> DepNodeParams<'a, 'gcx, 'tcx> for HirId {
 }
 
 /// A "work product" corresponds to a `.o` (or other) file that we
-/// save in between runs. These ids do not have a DefId but rather
+/// save in between runs. These IDs do not have a `DefId` but rather
 /// some independent path or string that persists between runs without
 /// the need to be mapped or unmapped. (This ensures we can serialize
 /// them even in the absence of a tcx.)
@@ -818,6 +825,6 @@ impl WorkProductId {
     }
 }
 
-impl_stable_hash_for!(struct ::dep_graph::WorkProductId {
+impl_stable_hash_for!(struct crate::dep_graph::WorkProductId {
     hash
 });
diff --git a/src/librustc/dep_graph/dep_tracking_map.rs b/src/librustc/dep_graph/dep_tracking_map.rs
index 331a9c6109c4c..94b832bea628e 100644
--- a/src/librustc/dep_graph/dep_tracking_map.rs
+++ b/src/librustc/dep_graph/dep_tracking_map.rs
@@ -2,7 +2,7 @@ use rustc_data_structures::fx::FxHashMap;
 use std::cell::RefCell;
 use std::hash::Hash;
 use std::marker::PhantomData;
-use util::common::MemoizationMap;
+use crate::util::common::MemoizationMap;
 
 use super::{DepKind, DepNodeIndex, DepGraph};
 
@@ -43,7 +43,7 @@ impl<M: DepTrackingMapConfig> MemoizationMap for RefCell<DepTrackingMap<M>> {
     ///
     /// Here, `[op]` represents whatever nodes `op` reads in the
     /// course of execution; `Map(key)` represents the node for this
-    /// map; and `CurrentTask` represents the current task when
+    /// map, and `CurrentTask` represents the current task when
     /// `memoize` is invoked.
     ///
     /// **Important:** when `op` is invoked, the current task will be
diff --git a/src/librustc/dep_graph/graph.rs b/src/librustc/dep_graph/graph.rs
index 501ef01d74c6e..8a2f79e6793c0 100644
--- a/src/librustc/dep_graph/graph.rs
+++ b/src/librustc/dep_graph/graph.rs
@@ -1,16 +1,17 @@
-use errors::DiagnosticBuilder;
+use errors::{Diagnostic, DiagnosticBuilder};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use smallvec::SmallVec;
-use rustc_data_structures::sync::{Lrc, Lock};
+use rustc_data_structures::sync::{Lrc, Lock, AtomicU32, Ordering};
 use std::env;
 use std::hash::Hash;
 use std::collections::hash_map::Entry;
-use ty::{self, TyCtxt};
-use util::common::{ProfileQueriesMsg, profq_msg};
+use crate::ty::{self, TyCtxt};
+use crate::util::common::{ProfileQueriesMsg, profq_msg};
+use parking_lot::{Mutex, Condvar};
 
-use ich::{StableHashingContext, StableHashingContextProvider, Fingerprint};
+use crate::ich::{StableHashingContext, StableHashingContextProvider, Fingerprint};
 
 use super::debug::EdgeFilter;
 use super::dep_node::{DepNode, DepKind, WorkProductId};
@@ -58,9 +59,15 @@ struct DepGraphData {
     /// nodes and edges as well as all fingerprints of nodes that have them.
     previous: PreviousDepGraph,
 
-    colors: Lock<DepNodeColorMap>,
+    colors: DepNodeColorMap,
 
-    /// When we load, there may be `.o` files, cached mir, or other such
+    /// A set of loaded diagnostics that have been emitted.
+    emitted_diagnostics: Mutex<FxHashSet<DepNodeIndex>>,
+
+    /// Used to wait for diagnostics to be emitted.
+    emitted_diagnostics_cond_var: Condvar,
+
+    /// When we load, there may be `.o` files, cached MIR, or other such
     /// things available to us. If we find that they are not dirty, we
     /// load the path to the file storing those work-products here into
     /// this map. We can later look for and extract that data.
@@ -72,6 +79,16 @@ struct DepGraphData {
     loaded_from_cache: Lock<FxHashMap<DepNodeIndex, bool>>,
 }
 
+pub fn hash_result<R>(hcx: &mut StableHashingContext<'_>, result: &R) -> Option<Fingerprint>
+where
+    R: for<'a> HashStable<StableHashingContext<'a>>,
+{
+    let mut stable_hasher = StableHasher::new();
+    result.hash_stable(hcx, &mut stable_hasher);
+
+    Some(stable_hasher.finish())
+}
+
 impl DepGraph {
 
     pub fn new(prev_graph: PreviousDepGraph,
@@ -83,8 +100,10 @@ impl DepGraph {
                 previous_work_products: prev_work_products,
                 dep_node_debug: Default::default(),
                 current: Lock::new(CurrentDepGraph::new(prev_graph_node_count)),
+                emitted_diagnostics: Default::default(),
+                emitted_diagnostics_cond_var: Condvar::new(),
                 previous: prev_graph,
-                colors: Lock::new(DepNodeColorMap::new(prev_graph_node_count)),
+                colors: DepNodeColorMap::new(prev_graph_node_count),
                 loaded_from_cache: Default::default(),
             })),
         }
@@ -96,7 +115,7 @@ impl DepGraph {
         }
     }
 
-    /// True if we are actually building the full dep-graph.
+    /// Returns `true` if we are actually building the full dep-graph, and `false` otherwise.
     #[inline]
     pub fn is_fully_enabled(&self) -> bool {
         self.data.is_some()
@@ -169,14 +188,16 @@ impl DepGraph {
     ///   `arg` parameter.
     ///
     /// [rustc guide]: https://rust-lang.github.io/rustc-guide/incremental-compilation.html
-    pub fn with_task<'gcx, C, A, R>(&self,
-                                   key: DepNode,
-                                   cx: C,
-                                   arg: A,
-                                   task: fn(C, A) -> R)
-                                   -> (R, DepNodeIndex)
-        where C: DepGraphSafe + StableHashingContextProvider<'gcx>,
-              R: HashStable<StableHashingContext<'gcx>>,
+    pub fn with_task<'a, C, A, R>(
+        &self,
+        key: DepNode,
+        cx: C,
+        arg: A,
+        task: fn(C, A) -> R,
+        hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
+    ) -> (R, DepNodeIndex)
+    where
+        C: DepGraphSafe + StableHashingContextProvider<'a>,
     {
         self.with_task_impl(key, cx, arg, false, task,
             |_key| Some(TaskDeps {
@@ -187,17 +208,18 @@ impl DepGraph {
             }),
             |data, key, fingerprint, task| {
                 data.borrow_mut().complete_task(key, task.unwrap(), fingerprint)
-            })
+            },
+            hash_result)
     }
 
     /// Creates a new dep-graph input with value `input`
-    pub fn input_task<'gcx, C, R>(&self,
+    pub fn input_task<'a, C, R>(&self,
                                    key: DepNode,
                                    cx: C,
                                    input: R)
                                    -> (R, DepNodeIndex)
-        where C: DepGraphSafe + StableHashingContextProvider<'gcx>,
-              R: HashStable<StableHashingContext<'gcx>>,
+        where C: DepGraphSafe + StableHashingContextProvider<'a>,
+              R: for<'b> HashStable<StableHashingContext<'b>>,
     {
         fn identity_fn<C, A>(_: C, arg: A) -> A {
             arg
@@ -207,10 +229,11 @@ impl DepGraph {
             |_| None,
             |data, key, fingerprint, _| {
                 data.borrow_mut().alloc_node(key, SmallVec::new(), fingerprint)
-            })
+            },
+            hash_result::<R>)
     }
 
-    fn with_task_impl<'gcx, C, A, R>(
+    fn with_task_impl<'a, C, A, R>(
         &self,
         key: DepNode,
         cx: C,
@@ -221,11 +244,11 @@ impl DepGraph {
         finish_task_and_alloc_depnode: fn(&Lock<CurrentDepGraph>,
                                           DepNode,
                                           Fingerprint,
-                                          Option<TaskDeps>) -> DepNodeIndex
+                                          Option<TaskDeps>) -> DepNodeIndex,
+        hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
     ) -> (R, DepNodeIndex)
     where
-        C: DepGraphSafe + StableHashingContextProvider<'gcx>,
-        R: HashStable<StableHashingContext<'gcx>>,
+        C: DepGraphSafe + StableHashingContextProvider<'a>,
     {
         if let Some(ref data) = self.data {
             let task_deps = create_task(key).map(|deps| Lock::new(deps));
@@ -260,34 +283,50 @@ impl DepGraph {
                 profq_msg(hcx.sess(), ProfileQueriesMsg::TaskEnd)
             };
 
-            let mut stable_hasher = StableHasher::new();
-            result.hash_stable(&mut hcx, &mut stable_hasher);
-
-            let current_fingerprint = stable_hasher.finish();
+            let current_fingerprint = hash_result(&mut hcx, &result);
 
             let dep_node_index = finish_task_and_alloc_depnode(
                 &data.current,
                 key,
-                current_fingerprint,
+                current_fingerprint.unwrap_or(Fingerprint::ZERO),
                 task_deps.map(|lock| lock.into_inner()),
             );
 
+            let print_status = cfg!(debug_assertions) && hcx.sess().opts.debugging_opts.dep_tasks;
+
             // Determine the color of the new DepNode.
             if let Some(prev_index) = data.previous.node_to_index_opt(&key) {
                 let prev_fingerprint = data.previous.fingerprint_by_index(prev_index);
 
-                let color = if current_fingerprint == prev_fingerprint {
-                    DepNodeColor::Green(dep_node_index)
+                let color = if let Some(current_fingerprint) = current_fingerprint {
+                    if current_fingerprint == prev_fingerprint {
+                        if print_status {
+                            eprintln!("[task::green] {:?}", key);
+                        }
+                        DepNodeColor::Green(dep_node_index)
+                    } else {
+                        if print_status {
+                            eprintln!("[task::red] {:?}", key);
+                        }
+                        DepNodeColor::Red
+                    }
                 } else {
+                    if print_status {
+                        eprintln!("[task::unknown] {:?}", key);
+                    }
+                    // Mark the node as Red if we can't hash the result
                     DepNodeColor::Red
                 };
 
-                let mut colors = data.colors.borrow_mut();
-                debug_assert!(colors.get(prev_index).is_none(),
-                              "DepGraph::with_task() - Duplicate DepNodeColor \
-                               insertion for {:?}", key);
+                debug_assert!(data.colors.get(prev_index).is_none(),
+                            "DepGraph::with_task() - Duplicate DepNodeColor \
+                            insertion for {:?}", key);
 
-                colors.insert(prev_index, color);
+                data.colors.insert(prev_index, color);
+            } else {
+                if print_status {
+                    eprintln!("[task::new] {:?}", key);
+                }
             }
 
             (result, dep_node_index)
@@ -296,8 +335,8 @@ impl DepGraph {
         }
     }
 
-    /// Execute something within an "anonymous" task, that is, a task the
-    /// DepNode of which is determined by the list of inputs it read from.
+    /// Executes something within an "anonymous" task, that is, a task the
+    /// `DepNode` of which is determined by the list of inputs it read from.
     pub fn with_anon_task<OP,R>(&self, dep_kind: DepKind, op: OP) -> (R, DepNodeIndex)
         where OP: FnOnce() -> R
     {
@@ -332,16 +371,18 @@ impl DepGraph {
         }
     }
 
-    /// Execute something within an "eval-always" task which is a task
-    // that runs whenever anything changes.
-    pub fn with_eval_always_task<'gcx, C, A, R>(&self,
-                                   key: DepNode,
-                                   cx: C,
-                                   arg: A,
-                                   task: fn(C, A) -> R)
-                                   -> (R, DepNodeIndex)
-        where C: DepGraphSafe + StableHashingContextProvider<'gcx>,
-              R: HashStable<StableHashingContext<'gcx>>,
+    /// Executes something within an "eval-always" task which is a task
+    /// that runs whenever anything changes.
+    pub fn with_eval_always_task<'a, C, A, R>(
+        &self,
+        key: DepNode,
+        cx: C,
+        arg: A,
+        task: fn(C, A) -> R,
+        hash_result: impl FnOnce(&mut StableHashingContext<'_>, &R) -> Option<Fingerprint>,
+    ) -> (R, DepNodeIndex)
+    where
+        C: DepGraphSafe + StableHashingContextProvider<'a>,
     {
         self.with_task_impl(key, cx, arg, false, task,
             |_| None,
@@ -351,7 +392,8 @@ impl DepGraph {
                     &DepNode::new_no_params(DepKind::Krate)
                 ];
                 current.alloc_node(key, smallvec![krate_idx], fingerprint)
-            })
+            },
+            hash_result)
     }
 
     #[inline]
@@ -411,7 +453,7 @@ impl DepGraph {
         self.data.as_ref().unwrap().previous.node_to_index(dep_node)
     }
 
-    /// Check whether a previous work product exists for `v` and, if
+    /// Checks whether a previous work product exists for `v` and, if
     /// so, return the path that leads to it. Used to skip doing work.
     pub fn previous_work_product(&self, v: &WorkProductId) -> Option<WorkProduct> {
         self.data
@@ -502,7 +544,7 @@ impl DepGraph {
     pub fn node_color(&self, dep_node: &DepNode) -> Option<DepNodeColor> {
         if let Some(ref data) = self.data {
             if let Some(prev_index) = data.previous.node_to_index_opt(dep_node) {
-                return data.colors.borrow().get(prev_index)
+                return data.colors.get(prev_index)
             } else {
                 // This is a node that did not exist in the previous compilation
                 // session, so we consider it to be red.
@@ -513,56 +555,89 @@ impl DepGraph {
         None
     }
 
-    pub fn try_mark_green<'tcx>(&self,
-                                tcx: TyCtxt<'_, 'tcx, 'tcx>,
-                                dep_node: &DepNode)
-                                -> Option<DepNodeIndex> {
-        debug!("try_mark_green({:?}) - BEGIN", dep_node);
-        let data = self.data.as_ref().unwrap();
+    /// Try to read a node index for the node dep_node.
+    /// A node will have an index, when it's already been marked green, or when we can mark it
+    /// green. This function will mark the current task as a reader of the specified node, when
+    /// a node index can be found for that node.
+    pub fn try_mark_green_and_read(
+        &self,
+        tcx: TyCtxt<'_, '_, '_>,
+        dep_node: &DepNode
+    ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
+        self.try_mark_green(tcx, dep_node).map(|(prev_index, dep_node_index)| {
+            debug_assert!(self.is_green(&dep_node));
+            self.read_index(dep_node_index);
+            (prev_index, dep_node_index)
+        })
+    }
 
-        #[cfg(not(parallel_queries))]
-        debug_assert!(!data.current.borrow().node_to_node_index.contains_key(dep_node));
-
-        if dep_node.kind.is_input() {
-            // We should only hit try_mark_green() for inputs that do not exist
-            // anymore in the current compilation session. Existing inputs are
-            // eagerly marked as either red/green before any queries are
-            // executed.
-            debug_assert!(dep_node.extract_def_id(tcx).is_none());
-            debug!("try_mark_green({:?}) - END - DepNode is deleted input", dep_node);
-            return None;
-        }
+    pub fn try_mark_green(
+        &self,
+        tcx: TyCtxt<'_, '_, '_>,
+        dep_node: &DepNode
+    ) -> Option<(SerializedDepNodeIndex, DepNodeIndex)> {
+        debug_assert!(!dep_node.kind.is_input());
+
+        // Return None if the dep graph is disabled
+        let data = self.data.as_ref()?;
+
+        // Return None if the dep node didn't exist in the previous session
+        let prev_index = data.previous.node_to_index_opt(dep_node)?;
 
-        let (prev_deps, prev_dep_node_index) = match data.previous.edges_from(dep_node) {
-            Some(prev) => {
+        match data.colors.get(prev_index) {
+            Some(DepNodeColor::Green(dep_node_index)) => Some((prev_index, dep_node_index)),
+            Some(DepNodeColor::Red) => None,
+            None => {
                 // This DepNode and the corresponding query invocation existed
                 // in the previous compilation session too, so we can try to
                 // mark it as green by recursively marking all of its
                 // dependencies green.
-                prev
-            }
-            None => {
-                // This DepNode did not exist in the previous compilation session,
-                // so we cannot mark it as green.
-                debug!("try_mark_green({:?}) - END - DepNode does not exist in \
-                        current compilation session anymore", dep_node);
-                return None
+                self.try_mark_previous_green(
+                    tcx.global_tcx(),
+                    data,
+                    prev_index,
+                    &dep_node
+                ).map(|dep_node_index| {
+                    (prev_index, dep_node_index)
+                })
             }
-        };
+        }
+    }
+
+    /// Try to mark a dep-node which existed in the previous compilation session as green.
+    fn try_mark_previous_green<'tcx>(
+        &self,
+        tcx: TyCtxt<'_, 'tcx, 'tcx>,
+        data: &DepGraphData,
+        prev_dep_node_index: SerializedDepNodeIndex,
+        dep_node: &DepNode
+    ) -> Option<DepNodeIndex> {
+        debug!("try_mark_previous_green({:?}) - BEGIN", dep_node);
+
+        #[cfg(not(parallel_compiler))]
+        {
+            debug_assert!(!data.current.borrow().node_to_node_index.contains_key(dep_node));
+            debug_assert!(data.colors.get(prev_dep_node_index).is_none());
+        }
 
-        debug_assert!(data.colors.borrow().get(prev_dep_node_index).is_none());
+        // We never try to mark inputs as green
+        debug_assert!(!dep_node.kind.is_input());
+
+        debug_assert_eq!(data.previous.index_to_node(prev_dep_node_index), *dep_node);
+
+        let prev_deps = data.previous.edge_targets_from(prev_dep_node_index);
 
         let mut current_deps = SmallVec::new();
 
         for &dep_dep_node_index in prev_deps {
-            let dep_dep_node_color = data.colors.borrow().get(dep_dep_node_index);
+            let dep_dep_node_color = data.colors.get(dep_dep_node_index);
 
             match dep_dep_node_color {
                 Some(DepNodeColor::Green(node_index)) => {
                     // This dependency has been marked as green before, we are
                     // still fine and can continue with checking the other
                     // dependencies.
-                    debug!("try_mark_green({:?}) --- found dependency {:?} to \
+                    debug!("try_mark_previous_green({:?}) --- found dependency {:?} to \
                             be immediately green",
                             dep_node,
                             data.previous.index_to_node(dep_dep_node_index));
@@ -573,7 +648,7 @@ impl DepGraph {
                     // compared to the previous compilation session. We cannot
                     // mark the DepNode as green and also don't need to bother
                     // with checking any of the other dependencies.
-                    debug!("try_mark_green({:?}) - END - dependency {:?} was \
+                    debug!("try_mark_previous_green({:?}) - END - dependency {:?} was \
                             immediately red",
                             dep_node,
                             data.previous.index_to_node(dep_dep_node_index));
@@ -585,12 +660,18 @@ impl DepGraph {
                     // We don't know the state of this dependency. If it isn't
                     // an input node, let's try to mark it green recursively.
                     if !dep_dep_node.kind.is_input() {
-                         debug!("try_mark_green({:?}) --- state of dependency {:?} \
+                         debug!("try_mark_previous_green({:?}) --- state of dependency {:?} \
                                  is unknown, trying to mark it green", dep_node,
                                  dep_dep_node);
 
-                        if let Some(node_index) = self.try_mark_green(tcx, dep_dep_node) {
-                            debug!("try_mark_green({:?}) --- managed to MARK \
+                        let node_index = self.try_mark_previous_green(
+                            tcx,
+                            data,
+                            dep_dep_node_index,
+                            dep_dep_node
+                        );
+                        if let Some(node_index) = node_index {
+                            debug!("try_mark_previous_green({:?}) --- managed to MARK \
                                     dependency {:?} as green", dep_node, dep_dep_node);
                             current_deps.push(node_index);
                             continue;
@@ -600,7 +681,7 @@ impl DepGraph {
                             DepKind::Hir |
                             DepKind::HirBody |
                             DepKind::CrateMetadata => {
-                                if dep_node.extract_def_id(tcx).is_none() {
+                                if dep_dep_node.extract_def_id(tcx).is_none() {
                                     // If the node does not exist anymore, we
                                     // just fail to mark green.
                                     return None
@@ -620,20 +701,20 @@ impl DepGraph {
                     }
 
                     // We failed to mark it green, so we try to force the query.
-                    debug!("try_mark_green({:?}) --- trying to force \
+                    debug!("try_mark_previous_green({:?}) --- trying to force \
                             dependency {:?}", dep_node, dep_dep_node);
-                    if ::ty::query::force_from_dep_node(tcx, dep_dep_node) {
-                        let dep_dep_node_color = data.colors.borrow().get(dep_dep_node_index);
+                    if crate::ty::query::force_from_dep_node(tcx, dep_dep_node) {
+                        let dep_dep_node_color = data.colors.get(dep_dep_node_index);
 
                         match dep_dep_node_color {
                             Some(DepNodeColor::Green(node_index)) => {
-                                debug!("try_mark_green({:?}) --- managed to \
+                                debug!("try_mark_previous_green({:?}) --- managed to \
                                         FORCE dependency {:?} to green",
                                         dep_node, dep_dep_node);
                                 current_deps.push(node_index);
                             }
                             Some(DepNodeColor::Red) => {
-                                debug!("try_mark_green({:?}) - END - \
+                                debug!("try_mark_previous_green({:?}) - END - \
                                         dependency {:?} was red after forcing",
                                        dep_node,
                                        dep_dep_node);
@@ -641,7 +722,7 @@ impl DepGraph {
                             }
                             None => {
                                 if !tcx.sess.has_errors() {
-                                    bug!("try_mark_green() - Forcing the DepNode \
+                                    bug!("try_mark_previous_green() - Forcing the DepNode \
                                           should have set its color")
                                 } else {
                                     // If the query we just forced has resulted
@@ -653,7 +734,7 @@ impl DepGraph {
                         }
                     } else {
                         // The DepNode could not be forced.
-                        debug!("try_mark_green({:?}) - END - dependency {:?} \
+                        debug!("try_mark_previous_green({:?}) - END - dependency {:?} \
                                 could not be forced", dep_node, dep_dep_node);
                         return None
                     }
@@ -680,44 +761,76 @@ impl DepGraph {
         };
 
         // ... emitting any stored diagnostic ...
-        if did_allocation {
-            // Only the thread which did the allocation emits the error messages
-
-            // FIXME: Ensure that these are printed before returning for all threads.
-            // Currently threads where did_allocation = false can continue on
-            // and emit other diagnostics before these diagnostics are emitted.
-            // Such diagnostics should be emitted after these.
-            // See https://github.com/rust-lang/rust/issues/48685
-            let diagnostics = tcx.queries.on_disk_cache
-                                 .load_diagnostics(tcx, prev_dep_node_index);
-
-            if diagnostics.len() > 0 {
-                let handle = tcx.sess.diagnostic();
 
-                // Promote the previous diagnostics to the current session.
-                tcx.queries.on_disk_cache
-                   .store_diagnostics(dep_node_index, diagnostics.clone().into());
+        let diagnostics = tcx.queries.on_disk_cache
+                                .load_diagnostics(tcx, prev_dep_node_index);
 
-                for diagnostic in diagnostics {
-                    DiagnosticBuilder::new_diagnostic(handle, diagnostic).emit();
-                }
-            }
+        if unlikely!(diagnostics.len() > 0) {
+            self.emit_diagnostics(
+                tcx,
+                data,
+                dep_node_index,
+                did_allocation,
+                diagnostics
+            );
         }
 
         // ... and finally storing a "Green" entry in the color map.
-        let mut colors = data.colors.borrow_mut();
         // Multiple threads can all write the same color here
-        #[cfg(not(parallel_queries))]
-        debug_assert!(colors.get(prev_dep_node_index).is_none(),
-                      "DepGraph::try_mark_green() - Duplicate DepNodeColor \
+        #[cfg(not(parallel_compiler))]
+        debug_assert!(data.colors.get(prev_dep_node_index).is_none(),
+                      "DepGraph::try_mark_previous_green() - Duplicate DepNodeColor \
                       insertion for {:?}", dep_node);
 
-        colors.insert(prev_dep_node_index, DepNodeColor::Green(dep_node_index));
+        data.colors.insert(prev_dep_node_index, DepNodeColor::Green(dep_node_index));
 
-        debug!("try_mark_green({:?}) - END - successfully marked as green", dep_node);
+        debug!("try_mark_previous_green({:?}) - END - successfully marked as green", dep_node);
         Some(dep_node_index)
     }
 
+    /// Atomically emits some loaded diagnotics, assuming that this only gets called with
+    /// `did_allocation` set to `true` on a single thread.
+    #[cold]
+    #[inline(never)]
+    fn emit_diagnostics<'tcx>(
+        &self,
+        tcx: TyCtxt<'_, 'tcx, 'tcx>,
+        data: &DepGraphData,
+        dep_node_index: DepNodeIndex,
+        did_allocation: bool,
+        diagnostics: Vec<Diagnostic>,
+    ) {
+        if did_allocation || !cfg!(parallel_compiler) {
+            // Only the thread which did the allocation emits the error messages
+            let handle = tcx.sess.diagnostic();
+
+            // Promote the previous diagnostics to the current session.
+            tcx.queries.on_disk_cache
+                .store_diagnostics(dep_node_index, diagnostics.clone().into());
+
+            for diagnostic in diagnostics {
+                DiagnosticBuilder::new_diagnostic(handle, diagnostic).emit();
+            }
+
+            #[cfg(parallel_compiler)]
+            {
+                // Mark the diagnostics and emitted and wake up waiters
+                data.emitted_diagnostics.lock().insert(dep_node_index);
+                data.emitted_diagnostics_cond_var.notify_all();
+            }
+        } else {
+            // The other threads will wait for the diagnostics to be emitted
+
+            let mut emitted_diagnostics = data.emitted_diagnostics.lock();
+            loop {
+                if emitted_diagnostics.contains(&dep_node_index) {
+                    break;
+                }
+                data.emitted_diagnostics_cond_var.wait(&mut emitted_diagnostics);
+            }
+        }
+    }
+
     // Returns true if the given node has been marked as green during the
     // current compilation session. Used in various assertions
     pub fn is_green(&self, dep_node: &DepNode) -> bool {
@@ -735,9 +848,8 @@ impl DepGraph {
     pub fn exec_cache_promotions<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) {
         let green_nodes: Vec<DepNode> = {
             let data = self.data.as_ref().unwrap();
-            let colors = data.colors.borrow();
-            colors.values.indices().filter_map(|prev_index| {
-                match colors.get(prev_index) {
+            data.colors.values.indices().filter_map(|prev_index| {
+                match data.colors.get(prev_index) {
                     Some(DepNodeColor::Green(_)) => {
                         let dep_node = data.previous.index_to_node(prev_index);
                         if dep_node.cache_on_disk(tcx) {
@@ -816,7 +928,7 @@ impl DepGraph {
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct WorkProduct {
     pub cgu_name: String,
-    /// Saved files associated with this CGU
+    /// Saved files associated with this CGU.
     pub saved_files: Vec<(WorkProductFileKind, String)>,
 }
 
@@ -840,17 +952,17 @@ pub(super) struct CurrentDepGraph {
     #[allow(dead_code)]
     forbidden_edge: Option<EdgeFilter>,
 
-    // Anonymous DepNodes are nodes the ID of which we compute from the list of
-    // their edges. This has the beneficial side-effect that multiple anonymous
-    // nodes can be coalesced into one without changing the semantics of the
-    // dependency graph. However, the merging of nodes can lead to a subtle
-    // problem during red-green marking: The color of an anonymous node from
-    // the current session might "shadow" the color of the node with the same
-    // ID from the previous session. In order to side-step this problem, we make
-    // sure that anon-node IDs allocated in different sessions don't overlap.
-    // This is implemented by mixing a session-key into the ID fingerprint of
-    // each anon node. The session-key is just a random number generated when
-    // the DepGraph is created.
+    /// Anonymous `DepNode`s are nodes whose IDs we compute from the list of
+    /// their edges. This has the beneficial side-effect that multiple anonymous
+    /// nodes can be coalesced into one without changing the semantics of the
+    /// dependency graph. However, the merging of nodes can lead to a subtle
+    /// problem during red-green marking: The color of an anonymous node from
+    /// the current session might "shadow" the color of the node with the same
+    /// ID from the previous session. In order to side-step this problem, we make
+    /// sure that anonymous `NodeId`s allocated in different sessions don't overlap.
+    /// This is implemented by mixing a session-key into the ID fingerprint of
+    /// each anon node. The session-key is just a random number generated when
+    /// the `DepGraph` is created.
     anon_id_seed: Fingerprint,
 
     total_read_count: u64,
@@ -1035,7 +1147,7 @@ pub struct TaskDeps {
 // A data structure that stores Option<DepNodeColor> values as a contiguous
 // array, using one u32 per entry.
 struct DepNodeColorMap {
-    values: IndexVec<SerializedDepNodeIndex, u32>,
+    values: IndexVec<SerializedDepNodeIndex, AtomicU32>,
 }
 
 const COMPRESSED_NONE: u32 = 0;
@@ -1045,12 +1157,12 @@ const COMPRESSED_FIRST_GREEN: u32 = 2;
 impl DepNodeColorMap {
     fn new(size: usize) -> DepNodeColorMap {
         DepNodeColorMap {
-            values: IndexVec::from_elem_n(COMPRESSED_NONE, size)
+            values: (0..size).map(|_| AtomicU32::new(COMPRESSED_NONE)).collect(),
         }
     }
 
     fn get(&self, index: SerializedDepNodeIndex) -> Option<DepNodeColor> {
-        match self.values[index] {
+        match self.values[index].load(Ordering::Acquire) {
             COMPRESSED_NONE => None,
             COMPRESSED_RED => Some(DepNodeColor::Red),
             value => Some(DepNodeColor::Green(DepNodeIndex::from_u32(
@@ -1059,10 +1171,10 @@ impl DepNodeColorMap {
         }
     }
 
-    fn insert(&mut self, index: SerializedDepNodeIndex, color: DepNodeColor) {
-        self.values[index] = match color {
+    fn insert(&self, index: SerializedDepNodeIndex, color: DepNodeColor) {
+        self.values[index].store(match color {
             DepNodeColor::Red => COMPRESSED_RED,
             DepNodeColor::Green(index) => index.as_u32() + COMPRESSED_FIRST_GREEN,
-        }
+        }, Ordering::Release)
     }
 }
diff --git a/src/librustc/dep_graph/mod.rs b/src/librustc/dep_graph/mod.rs
index 022caabcbf3a1..b84d2ad145889 100644
--- a/src/librustc/dep_graph/mod.rs
+++ b/src/librustc/dep_graph/mod.rs
@@ -10,7 +10,7 @@ pub mod cgu_reuse_tracker;
 
 pub use self::dep_tracking_map::{DepTrackingMap, DepTrackingMapConfig};
 pub use self::dep_node::{DepNode, DepKind, DepConstructor, WorkProductId, label_strs};
-pub use self::graph::{DepGraph, WorkProduct, DepNodeIndex, DepNodeColor, TaskDeps};
+pub use self::graph::{DepGraph, WorkProduct, DepNodeIndex, DepNodeColor, TaskDeps, hash_result};
 pub use self::graph::WorkProductFileKind;
 pub use self::prev::PreviousDepGraph;
 pub use self::query::DepGraphQuery;
diff --git a/src/librustc/dep_graph/prev.rs b/src/librustc/dep_graph/prev.rs
index 76d2954b4e35c..d971690bbe317 100644
--- a/src/librustc/dep_graph/prev.rs
+++ b/src/librustc/dep_graph/prev.rs
@@ -1,4 +1,4 @@
-use ich::Fingerprint;
+use crate::ich::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use super::dep_node::DepNode;
 use super::serialized::{SerializedDepGraph, SerializedDepNodeIndex};
@@ -19,14 +19,11 @@ impl PreviousDepGraph {
     }
 
     #[inline]
-    pub fn edges_from(&self,
-                      dep_node: &DepNode)
-                      -> Option<(&[SerializedDepNodeIndex], SerializedDepNodeIndex)> {
-        self.index
-            .get(dep_node)
-            .map(|&node_index| {
-                (self.data.edge_targets_from(node_index), node_index)
-            })
+    pub fn edge_targets_from(
+        &self,
+        dep_node_index: SerializedDepNodeIndex
+    ) -> &[SerializedDepNodeIndex] {
+        self.data.edge_targets_from(dep_node_index)
     }
 
     #[inline]
diff --git a/src/librustc/dep_graph/safe.rs b/src/librustc/dep_graph/safe.rs
index f1e8224a70d14..fc767defe9c71 100644
--- a/src/librustc/dep_graph/safe.rs
+++ b/src/librustc/dep_graph/safe.rs
@@ -1,9 +1,9 @@
 //! The `DepGraphSafe` trait
 
-use hir::BodyId;
-use hir::def_id::DefId;
+use crate::hir::BodyId;
+use crate::hir::def_id::DefId;
 use syntax::ast::NodeId;
-use ty::TyCtxt;
+use crate::ty::TyCtxt;
 
 /// The `DepGraphSafe` trait is used to specify what kinds of values
 /// are safe to "leak" into a task. The idea is that this should be
diff --git a/src/librustc/dep_graph/serialized.rs b/src/librustc/dep_graph/serialized.rs
index 3c04f01a5e1eb..b64f71ed908d8 100644
--- a/src/librustc/dep_graph/serialized.rs
+++ b/src/librustc/dep_graph/serialized.rs
@@ -1,7 +1,7 @@
 //! The data that we will serialize and deserialize.
 
-use dep_graph::DepNode;
-use ich::Fingerprint;
+use crate::dep_graph::DepNode;
+use crate::ich::Fingerprint;
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 
 newtype_index! {
diff --git a/src/librustc/diagnostics.rs b/src/librustc/diagnostics.rs
index 287a45a21eadf..00f9fa3a938d6 100644
--- a/src/librustc/diagnostics.rs
+++ b/src/librustc/diagnostics.rs
@@ -1,3 +1,4 @@
+// ignore-tidy-linelength
 #![allow(non_snake_case)]
 
 // Error messages for EXXXX errors.
@@ -362,6 +363,10 @@ struct Foo1 { x: &bool }
               // ^ expected lifetime parameter
 struct Foo2<'a> { x: &'a bool } // correct
 
+impl Foo2 {}
+  // ^^^^ expected lifetime parameter
+impl<'a> Foo2<'a> {} // correct
+
 struct Bar1 { x: Foo2 }
               // ^^^^ expected lifetime parameter
 struct Bar2<'a> { x: Foo2<'a> } // correct
@@ -403,11 +408,7 @@ fn bar(x: &str, y: &str) -> &str { }
 fn baz<'a>(x: &'a str, y: &str) -> &str { }
 ```
 
-Lifetime elision in implementation headers was part of the lifetime elision
-RFC. It is, however, [currently unimplemented][iss15872].
-
-[book-le]: https://doc.rust-lang.org/nightly/book/first-edition/lifetimes.html#lifetime-elision
-[iss15872]: https://github.com/rust-lang/rust/issues/15872
+[book-le]: https://doc.rust-lang.org/book/ch10-03-lifetime-syntax.html#lifetime-elision
 "##,
 
 E0119: r##"
@@ -642,7 +643,9 @@ attributes:
 #![no_std]
 ```
 
-See also https://doc.rust-lang.org/book/first-edition/no-stdlib.html
+See also the [unstable book][1].
+
+[1]: https://doc.rust-lang.org/unstable-book/language-features/lang-items.html#writing-an-executable-without-stdlib
 "##,
 
 E0214: r##"
@@ -766,11 +769,40 @@ struct Foo {
 These can be fixed by declaring lifetime parameters:
 
 ```
+struct Foo<'a> {
+    x: &'a str,
+}
+
 fn foo<'a>(x: &'a str) {}
+```
+
+Impl blocks declare lifetime parameters separately. You need to add lifetime
+parameters to an impl block if you're implementing a type that has a lifetime
+parameter of its own.
+For example:
 
+```compile_fail,E0261
 struct Foo<'a> {
     x: &'a str,
 }
+
+// error,  use of undeclared lifetime name `'a`
+impl Foo<'a> {
+    fn foo<'a>(x: &'a str) {}
+}
+```
+
+This is fixed by declaring the impl block like this:
+
+```
+struct Foo<'a> {
+    x: &'a str,
+}
+
+// correct
+impl<'a> Foo<'a> {
+    fn foo(x: &'a str) {}
+}
 ```
 "##,
 
@@ -1154,7 +1186,7 @@ impl Generator for AnotherImpl {
 fn main() {
     let cont: u32 = Generator::create();
     // error, impossible to choose one of Generator trait implementation
-    // Impl or AnotherImpl? Maybe anything else?
+    // Should it be Impl or AnotherImpl, maybe something else?
 }
 ```
 
@@ -1680,7 +1712,7 @@ fn main() {
 ```
 
 To understand better how closures work in Rust, read:
-https://doc.rust-lang.org/book/first-edition/closures.html
+https://doc.rust-lang.org/book/ch13-01-closures.html
 "##,
 
 E0580: r##"
diff --git a/src/librustc/hir/check_attr.rs b/src/librustc/hir/check_attr.rs
index b4a00715c0f22..ddc1eebe645ae 100644
--- a/src/librustc/hir/check_attr.rs
+++ b/src/librustc/hir/check_attr.rs
@@ -5,13 +5,12 @@
 //! item.
 
 
-use ty::TyCtxt;
-use ty::query::Providers;
-use ty::query::queries;
+use crate::ty::TyCtxt;
+use crate::ty::query::Providers;
 
-use hir;
-use hir::def_id::DefId;
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use std::fmt::{self, Display};
 use syntax_pos::Span;
 
@@ -92,7 +91,7 @@ struct CheckAttrVisitor<'a, 'tcx: 'a> {
 }
 
 impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
-    /// Check any attribute.
+    /// Checks any attribute.
     fn check_attributes(&self, item: &hir::Item, target: Target) {
         if target == Target::Fn || target == Target::Const {
             self.tcx.codegen_fn_attrs(self.tcx.hir().local_def_id(item.id));
@@ -116,7 +115,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         self.check_used(item, target);
     }
 
-    /// Check if an `#[inline]` is applied to a function or a closure.
+    /// Checks if an `#[inline]` is applied to a function or a closure.
     fn check_inline(&self, attr: &hir::Attribute, span: &Span, target: Target) {
         if target != Target::Fn && target != Target::Closure {
             struct_span_err!(self.tcx.sess,
@@ -128,7 +127,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         }
     }
 
-    /// Check if the `#[non_exhaustive]` attribute on an `item` is valid.
+    /// Checks if the `#[non_exhaustive]` attribute on an `item` is valid.
     fn check_non_exhaustive(&self, attr: &hir::Attribute, item: &hir::Item, target: Target) {
         match target {
             Target::Struct | Target::Enum => { /* Valid */ },
@@ -144,7 +143,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         }
     }
 
-    /// Check if the `#[marker]` attribute on an `item` is valid.
+    /// Checks if the `#[marker]` attribute on an `item` is valid.
     fn check_marker(&self, attr: &hir::Attribute, item: &hir::Item, target: Target) {
         match target {
             Target::Trait => { /* Valid */ },
@@ -158,7 +157,7 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
         }
     }
 
-    /// Check if the `#[repr]` attributes on `item` are valid.
+    /// Checks if the `#[repr]` attributes on `item` are valid.
     fn check_repr(&self, item: &hir::Item, target: Target) {
         // Extract the names of all repr hints, e.g., [foo, bar, align] for:
         // ```
@@ -187,8 +186,8 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
             };
 
             let (article, allowed_targets) = match &*name.as_str() {
-                "C" => {
-                    is_c = true;
+                "C" | "align" => {
+                    is_c |= name == "C";
                     if target != Target::Struct &&
                             target != Target::Union &&
                             target != Target::Enum {
@@ -213,14 +212,6 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
                         continue
                     }
                 }
-                "align" => {
-                    if target != Target::Struct &&
-                            target != Target::Union {
-                        ("a", "struct or union")
-                    } else {
-                        continue
-                    }
-                }
                 "transparent" => {
                     is_transparent = true;
                     if target != Target::Struct {
@@ -283,8 +274,8 @@ impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
 
     fn check_stmt_attributes(&self, stmt: &hir::Stmt) {
         // When checking statements ignore expressions, they will be checked later
-        if let hir::StmtKind::Decl(_, _) = stmt.node {
-            for attr in stmt.node.attrs() {
+        if let hir::StmtKind::Local(ref l) = stmt.node {
+            for attr in l.attrs.iter() {
                 if attr.check_name("inline") {
                     self.check_inline(attr, &stmt.span, Target::Statement);
                 }
@@ -355,7 +346,7 @@ impl<'a, 'tcx> Visitor<'tcx> for CheckAttrVisitor<'a, 'tcx> {
 
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &module in tcx.hir().krate().modules.keys() {
-        queries::check_mod_attrs::ensure(tcx, tcx.hir().local_def_id(module));
+        tcx.ensure().check_mod_attrs(tcx.hir().local_def_id(module));
     }
 }
 
@@ -363,7 +354,7 @@ fn is_c_like_enum(item: &hir::Item) -> bool {
     if let hir::ItemKind::Enum(ref def, _) = item.node {
         for variant in &def.variants {
             match variant.node.data {
-                hir::VariantData::Unit(_) => { /* continue */ }
+                hir::VariantData::Unit(..) => { /* continue */ }
                 _ => { return false; }
             }
         }
diff --git a/src/librustc/hir/def.rs b/src/librustc/hir/def.rs
index 8a74c51d3f723..f6d864f5b404d 100644
--- a/src/librustc/hir/def.rs
+++ b/src/librustc/hir/def.rs
@@ -1,10 +1,10 @@
-use hir::def_id::DefId;
-use util::nodemap::{NodeMap, DefIdMap};
+use crate::hir::def_id::DefId;
+use crate::util::nodemap::{NodeMap, DefIdMap};
 use syntax::ast;
 use syntax::ext::base::MacroKind;
 use syntax_pos::Span;
-use hir;
-use ty;
+use crate::hir;
+use crate::ty;
 
 use self::Namespace::*;
 
@@ -58,6 +58,7 @@ pub enum Def {
     // Value namespace
     Fn(DefId),
     Const(DefId),
+    ConstParam(DefId),
     Static(DefId, bool /* is_mutbl */),
     StructCtor(DefId, CtorKind), // `DefId` refers to `NodeId` of the struct's constructor
     VariantCtor(DefId, CtorKind), // `DefId` refers to the enum variant
@@ -181,7 +182,7 @@ impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
 }
 
 impl<T> PerNS<Option<T>> {
-    /// Returns whether all the items in this collection are `None`.
+    /// Returns `true` if all the items in this collection are `None`.
     pub fn is_empty(&self) -> bool {
         self.type_ns.is_none() && self.value_ns.is_none() && self.macro_ns.is_none()
     }
@@ -252,18 +253,21 @@ impl NonMacroAttrKind {
 }
 
 impl Def {
+    /// Return the `DefId` of this `Def` if it has an id, else panic.
     pub fn def_id(&self) -> DefId {
         self.opt_def_id().unwrap_or_else(|| {
             bug!("attempted .def_id() on invalid def: {:?}", self)
         })
     }
 
+    /// Return `Some(..)` with the `DefId` of this `Def` if it has a id, else `None`.
     pub fn opt_def_id(&self) -> Option<DefId> {
         match *self {
             Def::Fn(id) | Def::Mod(id) | Def::Static(id, _) |
             Def::Variant(id) | Def::VariantCtor(id, ..) | Def::Enum(id) |
             Def::TyAlias(id) | Def::TraitAlias(id) |
-            Def::AssociatedTy(id) | Def::TyParam(id) | Def::Struct(id) | Def::StructCtor(id, ..) |
+            Def::AssociatedTy(id) | Def::TyParam(id) | Def::ConstParam(id) | Def::Struct(id) |
+            Def::StructCtor(id, ..) |
             Def::Union(id) | Def::Trait(id) | Def::Method(id) | Def::Const(id) |
             Def::AssociatedConst(id) | Def::Macro(id, ..) |
             Def::Existential(id) | Def::AssociatedExistential(id) | Def::ForeignTy(id) => {
@@ -284,6 +288,14 @@ impl Def {
         }
     }
 
+    /// Return the `DefId` of this `Def` if it represents a module.
+    pub fn mod_def_id(&self) -> Option<DefId> {
+        match *self {
+            Def::Mod(id) => Some(id),
+            _ => None,
+        }
+    }
+
     /// A human readable name for the def kind ("function", "module", etc.).
     pub fn kind_name(&self) -> &'static str {
         match *self {
@@ -312,6 +324,7 @@ impl Def {
             Def::Const(..) => "constant",
             Def::AssociatedConst(..) => "associated constant",
             Def::TyParam(..) => "type parameter",
+            Def::ConstParam(..) => "const parameter",
             Def::PrimTy(..) => "builtin type",
             Def::Local(..) => "local variable",
             Def::Upvar(..) => "closure capture",
diff --git a/src/librustc/hir/def_id.rs b/src/librustc/hir/def_id.rs
index 9181076740ba0..ed1c15a73c260 100644
--- a/src/librustc/hir/def_id.rs
+++ b/src/librustc/hir/def_id.rs
@@ -1,6 +1,6 @@
-use ty;
-use ty::TyCtxt;
-use hir::map::definitions::FIRST_FREE_HIGH_DEF_INDEX;
+use crate::ty;
+use crate::ty::TyCtxt;
+use crate::hir::map::definitions::FIRST_FREE_HIGH_DEF_INDEX;
 use rustc_data_structures::indexed_vec::Idx;
 use serialize;
 use std::fmt;
@@ -229,7 +229,7 @@ impl fmt::Debug for DefId {
 }
 
 impl DefId {
-    /// Make a local `DefId` with the given index.
+    /// Makes a local `DefId` from the given `DefIndex`.
     #[inline]
     pub fn local(index: DefIndex) -> DefId {
         DefId { krate: LOCAL_CRATE, index: index }
diff --git a/src/librustc/hir/intravisit.rs b/src/librustc/hir/intravisit.rs
index f633703be56d4..4a2bc213fea80 100644
--- a/src/librustc/hir/intravisit.rs
+++ b/src/librustc/hir/intravisit.rs
@@ -4,7 +4,7 @@
 //! `super::itemlikevisit::ItemLikeVisitor` trait.**
 //!
 //! If you have decided to use this visitor, here are some general
-//! notes on how to do it:
+//! notes on how to do so:
 //!
 //! Each overridden visit method has full control over what
 //! happens with its node, it can do its own traversal of the node's children,
@@ -33,13 +33,11 @@
 
 use syntax::ast::{NodeId, CRATE_NODE_ID, Ident, Name, Attribute};
 use syntax_pos::Span;
-use hir::*;
-use hir::def::Def;
-use hir::map::{self, Map};
+use crate::hir::*;
+use crate::hir::def::Def;
+use crate::hir::map::Map;
 use super::itemlikevisit::DeepVisitor;
 
-use std::cmp;
-
 #[derive(Copy, Clone)]
 pub enum FnKind<'a> {
     /// `#[xxx] pub async/const/extern "Abi" fn foo()`
@@ -88,7 +86,7 @@ pub enum NestedVisitorMap<'this, 'tcx: 'this> {
     /// using this setting.
     OnlyBodies(&'this Map<'tcx>),
 
-    /// Visit all nested things, including item-likes.
+    /// Visits all nested things, including item-likes.
     ///
     /// **This is an unusual choice.** It is used when you want to
     /// process everything within their lexical context. Typically you
@@ -98,7 +96,7 @@ pub enum NestedVisitorMap<'this, 'tcx: 'this> {
 
 impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
     /// Returns the map to use for an "intra item-like" thing (if any).
-    /// e.g., function body.
+    /// E.g., function body.
     pub fn intra(self) -> Option<&'this Map<'tcx>> {
         match self {
             NestedVisitorMap::None => None,
@@ -108,7 +106,7 @@ impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
     }
 
     /// Returns the map to use for an "item-like" thing (if any).
-    /// e.g., item, impl-item.
+    /// E.g., item, impl-item.
     pub fn inter(self) -> Option<&'this Map<'tcx>> {
         match self {
             NestedVisitorMap::None => None,
@@ -119,7 +117,7 @@ impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
 }
 
 /// Each method of the Visitor trait is a hook to be potentially
-/// overridden.  Each method's default implementation recursively visits
+/// overridden. Each method's default implementation recursively visits
 /// the substructure of the input via the corresponding `walk` method;
 /// e.g., the `visit_mod` method by default calls `intravisit::walk_mod`.
 ///
@@ -131,7 +129,7 @@ impl<'this, 'tcx> NestedVisitorMap<'this, 'tcx> {
 /// on `visit_nested_item` for details on how to visit nested items.
 ///
 /// If you want to ensure that your code handles every variant
-/// explicitly, you need to override each method.  (And you also need
+/// explicitly, you need to override each method. (And you also need
 /// to monitor future changes to `Visitor` in case a new method with a
 /// new default implementation gets introduced.)
 pub trait Visitor<'v> : Sized {
@@ -205,7 +203,7 @@ pub trait Visitor<'v> : Sized {
         }
     }
 
-    /// Visit the top-level item and (optionally) nested items / impl items. See
+    /// Visits the top-level item and (optionally) nested items / impl items. See
     /// `visit_nested_item` for details.
     fn visit_item(&mut self, i: &'v Item) {
         walk_item(self, i)
@@ -216,7 +214,7 @@ pub trait Visitor<'v> : Sized {
     }
 
     /// When invoking `visit_all_item_likes()`, you need to supply an
-    /// item-like visitor.  This method converts a "intra-visit"
+    /// item-like visitor. This method converts a "intra-visit"
     /// visitor into an item-like visitor that walks the entire tree.
     /// If you use this, you probably don't want to process the
     /// contents of nested item-like things, since the outer loop will
@@ -260,9 +258,6 @@ pub trait Visitor<'v> : Sized {
     fn visit_pat(&mut self, p: &'v Pat) {
         walk_pat(self, p)
     }
-    fn visit_decl(&mut self, d: &'v Decl) {
-        walk_decl(self, d)
-    }
     fn visit_anon_const(&mut self, c: &'v AnonConst) {
         walk_anon_const(self, c)
     }
@@ -339,6 +334,7 @@ pub trait Visitor<'v> : Sized {
         match generic_arg {
             GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
             GenericArg::Type(ty) => self.visit_ty(ty),
+            GenericArg::Const(ct) => self.visit_anon_const(&ct.value),
         }
     }
     fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
@@ -699,7 +695,7 @@ pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat) {
         PatKind::Ref(ref subpattern, _) => {
             visitor.visit_pat(subpattern)
         }
-        PatKind::Binding(_, canonical_id, ident, ref optional_subpattern) => {
+        PatKind::Binding(_, canonical_id, _hir_id, ident, ref optional_subpattern) => {
             visitor.visit_def_mention(Def::Local(canonical_id));
             visitor.visit_ident(ident);
             walk_list!(visitor, visit_pat, optional_subpattern);
@@ -757,6 +753,7 @@ pub fn walk_generic_param<'v, V: Visitor<'v>>(visitor: &mut V, param: &'v Generi
     match param.kind {
         GenericParamKind::Lifetime { .. } => {}
         GenericParamKind::Type { ref default, .. } => walk_list!(visitor, visit_ty, default),
+        GenericParamKind::Const { ref ty } => visitor.visit_ty(ty),
     }
     walk_list!(visitor, visit_param_bound, &param.bounds);
 }
@@ -953,26 +950,17 @@ pub fn walk_block<'v, V: Visitor<'v>>(visitor: &mut V, block: &'v Block) {
 }
 
 pub fn walk_stmt<'v, V: Visitor<'v>>(visitor: &mut V, statement: &'v Stmt) {
+    visitor.visit_id(statement.id);
     match statement.node {
-        StmtKind::Decl(ref declaration, id) => {
-            visitor.visit_id(id);
-            visitor.visit_decl(declaration)
-        }
-        StmtKind::Expr(ref expression, id) |
-        StmtKind::Semi(ref expression, id) => {
-            visitor.visit_id(id);
+        StmtKind::Local(ref local) => visitor.visit_local(local),
+        StmtKind::Item(item) => visitor.visit_nested_item(item),
+        StmtKind::Expr(ref expression) |
+        StmtKind::Semi(ref expression) => {
             visitor.visit_expr(expression)
         }
     }
 }
 
-pub fn walk_decl<'v, V: Visitor<'v>>(visitor: &mut V, declaration: &'v Decl) {
-    match declaration.node {
-        DeclKind::Local(ref local) => visitor.visit_local(local),
-        DeclKind::Item(item) => visitor.visit_nested_item(item),
-    }
-}
-
 pub fn walk_anon_const<'v, V: Visitor<'v>>(visitor: &mut V, constant: &'v AnonConst) {
     visitor.visit_id(constant.id);
     visitor.visit_nested_body(constant.body);
@@ -1133,57 +1121,3 @@ pub fn walk_defaultness<'v, V: Visitor<'v>>(_: &mut V, _: &'v Defaultness) {
     // the right thing to do, should content be added in the future,
     // would be to walk it.
 }
-
-#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct IdRange {
-    pub min: NodeId,
-    pub max: NodeId,
-}
-
-impl IdRange {
-    pub fn max() -> IdRange {
-        IdRange {
-            min: NodeId::MAX,
-            max: NodeId::from_u32(0),
-        }
-    }
-
-    pub fn empty(&self) -> bool {
-        self.min >= self.max
-    }
-
-    pub fn contains(&self, id: NodeId) -> bool {
-        id >= self.min && id < self.max
-    }
-
-    pub fn add(&mut self, id: NodeId) {
-        self.min = cmp::min(self.min, id);
-        self.max = cmp::max(self.max, NodeId::from_u32(id.as_u32() + 1));
-    }
-}
-
-
-pub struct IdRangeComputingVisitor<'a, 'hir: 'a> {
-    result: IdRange,
-    map: &'a map::Map<'hir>,
-}
-
-impl<'a, 'hir> IdRangeComputingVisitor<'a, 'hir> {
-    pub fn new(map: &'a map::Map<'hir>) -> IdRangeComputingVisitor<'a, 'hir> {
-        IdRangeComputingVisitor { result: IdRange::max(), map: map }
-    }
-
-    pub fn result(&self) -> IdRange {
-        self.result
-    }
-}
-
-impl<'a, 'hir> Visitor<'hir> for IdRangeComputingVisitor<'a, 'hir> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'hir> {
-        NestedVisitorMap::OnlyBodies(&self.map)
-    }
-
-    fn visit_id(&mut self, id: NodeId) {
-        self.result.add(id);
-    }
-}
diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 8badcbfc1b301..9f48a628274db 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -3,24 +3,24 @@
 //! Since the AST and HIR are fairly similar, this is mostly a simple procedure,
 //! much like a fold. Where lowering involves a bit more work things get more
 //! interesting and there are some invariants you should know about. These mostly
-//! concern spans and ids.
+//! concern spans and IDs.
 //!
 //! Spans are assigned to AST nodes during parsing and then are modified during
 //! expansion to indicate the origin of a node and the process it went through
-//! being expanded. Ids are assigned to AST nodes just before lowering.
+//! being expanded. IDs are assigned to AST nodes just before lowering.
 //!
-//! For the simpler lowering steps, ids and spans should be preserved. Unlike
+//! For the simpler lowering steps, IDs and spans should be preserved. Unlike
 //! expansion we do not preserve the process of lowering in the spans, so spans
 //! should not be modified here. When creating a new node (as opposed to
-//! 'folding' an existing one), then you create a new id using `next_id()`.
+//! 'folding' an existing one), then you create a new ID using `next_id()`.
 //!
-//! You must ensure that ids are unique. That means that you should only use the
-//! id from an AST node in a single HIR node (you can assume that AST node ids
-//! are unique). Every new node must have a unique id. Avoid cloning HIR nodes.
-//! If you do, you must then set the new node's id to a fresh one.
+//! You must ensure that IDs are unique. That means that you should only use the
+//! ID from an AST node in a single HIR node (you can assume that AST node IDs
+//! are unique). Every new node must have a unique ID. Avoid cloning HIR nodes.
+//! If you do, you must then set the new node's ID to a fresh one.
 //!
 //! Spans are used for error messages and for tools to map semantics back to
-//! source code. It is therefore not as important with spans as ids to be strict
+//! source code. It is therefore not as important with spans as IDs to be strict
 //! about use (you can't break the compiler by screwing up a span). Obviously, a
 //! HIR node can only have a single span. But multiple nodes can have the same
 //! span and spans don't need to be kept in order, etc. Where code is preserved
@@ -30,23 +30,25 @@
 //! get confused if the spans from leaf AST nodes occur in multiple places
 //! in the HIR, especially for multiple identifiers.
 
-use dep_graph::DepGraph;
-use hir::{self, ParamName};
-use hir::HirVec;
-use hir::map::{DefKey, DefPathData, Definitions};
-use hir::def_id::{DefId, DefIndex, DefIndexAddressSpace, CRATE_DEF_INDEX};
-use hir::def::{Def, PathResolution, PerNS};
-use hir::GenericArg;
-use lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
+use crate::dep_graph::DepGraph;
+use crate::hir::{self, ParamName};
+use crate::hir::HirVec;
+use crate::hir::map::{DefKey, DefPathData, Definitions};
+use crate::hir::def_id::{DefId, DefIndex, DefIndexAddressSpace, CRATE_DEF_INDEX};
+use crate::hir::def::{Def, PathResolution, PerNS};
+use crate::hir::{GenericArg, ConstArg};
+use crate::lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
                     ELIDED_LIFETIMES_IN_PATHS};
-use middle::cstore::CrateStore;
+use crate::middle::cstore::CrateStore;
+use crate::session::Session;
+use crate::session::config::nightly_options;
+use crate::util::common::FN_OUTPUT_NAME;
+use crate::util::nodemap::{DefIdMap, NodeMap};
+use errors::Applicability;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::thin_vec::ThinVec;
-use session::Session;
-use session::config::nightly_options;
-use util::common::FN_OUTPUT_NAME;
-use util::nodemap::{DefIdMap, NodeMap};
+use rustc_data_structures::sync::Lrc;
 
 use std::collections::{BTreeSet, BTreeMap};
 use std::fmt::Debug;
@@ -143,7 +145,7 @@ pub trait Resolver {
         is_value: bool,
     ) -> hir::Path;
 
-    /// Obtain the resolution for a node-id.
+    /// Obtain the resolution for a `NodeId`.
     fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution>;
 
     /// Obtain the possible resolutions for the given `use` statement.
@@ -272,10 +274,10 @@ enum ParenthesizedGenericArgs {
 }
 
 /// What to do when we encounter an **anonymous** lifetime
-/// reference. Anonymous lifetime references come in two flavors.  You
+/// reference. Anonymous lifetime references come in two flavors. You
 /// have implicit, or fully elided, references to lifetimes, like the
 /// one in `&T` or `Ref<T>`, and you have `'_` lifetimes, like `&'_ T`
-/// or `Ref<'_, T>`.  These often behave the same, but not always:
+/// or `Ref<'_, T>`. These often behave the same, but not always:
 ///
 /// - certain usages of implicit references are deprecated, like
 ///   `Ref<T>`, and we sometimes just give hard errors in those cases
@@ -680,13 +682,20 @@ impl<'a> LoweringContext<'a> {
         Ident::with_empty_ctxt(Symbol::gensym(s))
     }
 
-    fn allow_internal_unstable(&self, reason: CompilerDesugaringKind, span: Span) -> Span {
+    /// Reuses the span but adds information like the kind of the desugaring and features that are
+    /// allowed inside this span.
+    fn mark_span_with_reason(
+        &self,
+        reason: CompilerDesugaringKind,
+        span: Span,
+        allow_internal_unstable: Option<Lrc<[Symbol]>>,
+    ) -> Span {
         let mark = Mark::fresh(Mark::root());
         mark.set_expn_info(source_map::ExpnInfo {
             call_site: span,
             def_site: Some(span),
             format: source_map::CompilerDesugaring(reason),
-            allow_internal_unstable: true,
+            allow_internal_unstable,
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: source_map::hygiene::default_edition(),
@@ -740,7 +749,7 @@ impl<'a> LoweringContext<'a> {
         let params = lifetimes_to_define
             .into_iter()
             .map(|(span, hir_name)| {
-                let def_node_id = self.next_id().node_id;
+                let LoweredNodeId { node_id, hir_id } = self.next_id();
 
                 // Get the name we'll use to make the def-path. Note
                 // that collisions are ok here and this shouldn't
@@ -763,7 +772,7 @@ impl<'a> LoweringContext<'a> {
                 // Add a definition for the in-band lifetime def.
                 self.resolver.definitions().create_def_with_parent(
                     parent_id.index,
-                    def_node_id,
+                    node_id,
                     DefPathData::LifetimeParam(str_name),
                     DefIndexAddressSpace::High,
                     Mark::root(),
@@ -771,7 +780,8 @@ impl<'a> LoweringContext<'a> {
                 );
 
                 hir::GenericParam {
-                    id: def_node_id,
+                    id: node_id,
+                    hir_id,
                     name: hir_name,
                     attrs: hir_vec![],
                     bounds: hir_vec![],
@@ -962,7 +972,13 @@ impl<'a> LoweringContext<'a> {
             attrs: ThinVec::new(),
         };
 
-        let unstable_span = self.allow_internal_unstable(CompilerDesugaringKind::Async, span);
+        let unstable_span = self.mark_span_with_reason(
+            CompilerDesugaringKind::Async,
+            span,
+            Some(vec![
+                Symbol::intern("gen_future"),
+            ].into()),
+        );
         let gen_future = self.expr_std_path(
             unstable_span, &["future", "from_generator"], None, ThinVec::new());
         hir::ExprKind::Call(P(gen_future), hir_vec![generator])
@@ -1137,8 +1153,11 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_ty_binding(&mut self, b: &TypeBinding,
                         itctx: ImplTraitContext<'_>) -> hir::TypeBinding {
+        let LoweredNodeId { node_id, hir_id } = self.lower_node_id(b.id);
+
         hir::TypeBinding {
-            id: self.lower_node_id(b.id).node_id,
+            id: node_id,
+            hir_id,
             ident: b.ident,
             ty: self.lower_ty(&b.ty, itctx),
             span: b.span,
@@ -1152,6 +1171,12 @@ impl<'a> LoweringContext<'a> {
         match arg {
             ast::GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.lower_lifetime(&lt)),
             ast::GenericArg::Type(ty) => GenericArg::Type(self.lower_ty_direct(&ty, itctx)),
+            ast::GenericArg::Const(ct) => {
+                GenericArg::Const(ConstArg {
+                    value: self.lower_anon_const(&ct),
+                    span: ct.value.span,
+                })
+            }
         }
     }
 
@@ -1260,7 +1285,7 @@ impl<'a> LoweringContext<'a> {
                         )
                     }
                     ImplTraitContext::Universal(in_band_ty_params) => {
-                        self.lower_node_id(def_node_id);
+                        let LoweredNodeId { node_id: _, hir_id } =  self.lower_node_id(def_node_id);
                         // Add a definition for the in-band `Param`.
                         let def_index = self
                             .resolver
@@ -1276,6 +1301,7 @@ impl<'a> LoweringContext<'a> {
                         let ident = Ident::from_str(&pprust::ty_to_string(t)).with_span_pos(span);
                         in_band_ty_params.push(hir::GenericParam {
                             id: def_node_id,
+                            hir_id,
                             name: ParamName::Plain(ident),
                             pure_wrt_drop: false,
                             attrs: hir_vec![],
@@ -1345,9 +1371,10 @@ impl<'a> LoweringContext<'a> {
         // desugaring that explicitly states that we don't want to track that.
         // Not tracking it makes lints in rustc and clippy very fragile as
         // frequently opened issues show.
-        let exist_ty_span = self.allow_internal_unstable(
+        let exist_ty_span = self.mark_span_with_reason(
             CompilerDesugaringKind::ExistentialReturnType,
             span,
+            None,
         );
 
         let exist_ty_def_index = self
@@ -1367,11 +1394,13 @@ impl<'a> LoweringContext<'a> {
         );
 
         self.with_hir_id_owner(exist_ty_node_id, |lctx| {
+            let LoweredNodeId { node_id, hir_id } = lctx.next_id();
             let exist_ty_item_kind = hir::ItemKind::Existential(hir::ExistTy {
                 generics: hir::Generics {
                     params: lifetime_defs,
                     where_clause: hir::WhereClause {
-                        id: lctx.next_id().node_id,
+                        id: node_id,
+                        hir_id,
                         predicates: Vec::new().into(),
                     },
                     span,
@@ -1504,8 +1533,10 @@ impl<'a> LoweringContext<'a> {
                     && !self.already_defined_lifetimes.contains(&name) {
                     self.already_defined_lifetimes.insert(name);
 
+                    let LoweredNodeId { node_id, hir_id } = self.context.next_id();
                     self.output_lifetimes.push(hir::GenericArg::Lifetime(hir::Lifetime {
-                        id: self.context.next_id().node_id,
+                        id: node_id,
+                        hir_id,
                         span: lifetime.span,
                         name,
                     }));
@@ -1514,7 +1545,8 @@ impl<'a> LoweringContext<'a> {
                     // definitions will go into the explicit `existential type`
                     // declaration and thus need to have their owner set to that item
                     let def_node_id = self.context.sess.next_node_id();
-                    let _ = self.context.lower_node_id_with_owner(def_node_id, self.exist_ty_id);
+                    let LoweredNodeId { node_id: _, hir_id } =
+                        self.context.lower_node_id_with_owner(def_node_id, self.exist_ty_id);
                     self.context.resolver.definitions().create_def_with_parent(
                         self.parent,
                         def_node_id,
@@ -1538,6 +1570,7 @@ impl<'a> LoweringContext<'a> {
 
                     self.output_lifetime_params.push(hir::GenericParam {
                         id: def_node_id,
+                        hir_id,
                         name,
                         span: lifetime.span,
                         pure_wrt_drop: false,
@@ -1806,7 +1839,7 @@ impl<'a> LoweringContext<'a> {
         explicit_owner: Option<NodeId>,
     ) -> hir::PathSegment {
         let (mut generic_args, infer_types) = if let Some(ref generic_args) = segment.args {
-            let msg = "parenthesized parameters may only be used with a trait";
+            let msg = "parenthesized type parameters may only be used with a `Fn` trait";
             match **generic_args {
                 GenericArgs::AngleBracketed(ref data) => {
                     self.lower_angle_bracketed_parameter_data(data, param_mode, itctx)
@@ -1823,10 +1856,25 @@ impl<'a> LoweringContext<'a> {
                         (hir::GenericArgs::none(), true)
                     }
                     ParenthesizedGenericArgs::Err => {
-                        struct_span_err!(self.sess, data.span, E0214, "{}", msg)
-                            .span_label(data.span, "only traits may use parentheses")
-                            .emit();
-                        (hir::GenericArgs::none(), true)
+                        let mut err = struct_span_err!(self.sess, data.span, E0214, "{}", msg);
+                        err.span_label(data.span, "only `Fn` traits may use parentheses");
+                        if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
+                            // Do not suggest going from `Trait()` to `Trait<>`
+                            if data.inputs.len() > 0 {
+                                err.span_suggestion(
+                                    data.span,
+                                    "use angle brackets instead",
+                                    format!("<{}>", &snippet[1..snippet.len() - 1]),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            }
+                        };
+                        err.emit();
+                        (self.lower_angle_bracketed_parameter_data(
+                            &data.as_angle_bracketed_args(),
+                            param_mode,
+                            itctx).0,
+                         false)
                     }
                 },
             }
@@ -1888,6 +1936,7 @@ impl<'a> LoweringContext<'a> {
         hir::PathSegment::new(
             segment.ident,
             Some(id.node_id),
+            Some(id.hir_id),
             Some(def),
             generic_args,
             infer_types,
@@ -1915,7 +1964,7 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_parenthesized_parameter_data(
         &mut self,
-        data: &ParenthesisedArgs,
+        data: &ParenthesizedArgs,
     ) -> (hir::GenericArgs, bool) {
         // Switch to `PassThrough` mode for anonymous lifetimes: this
         // means that we permit things like `&Ref<T>`, where `Ref` has
@@ -1925,7 +1974,7 @@ impl<'a> LoweringContext<'a> {
         self.with_anonymous_lifetime_mode(
             AnonymousLifetimeMode::PassThrough,
             |this| {
-                let &ParenthesisedArgs { ref inputs, ref output, span } = data;
+                let &ParenthesizedArgs { ref inputs, ref output, span } = data;
                 let inputs = inputs
                     .iter()
                     .map(|ty| this.lower_ty_direct(ty, ImplTraitContext::disallowed()))
@@ -1934,13 +1983,15 @@ impl<'a> LoweringContext<'a> {
                     let LoweredNodeId { node_id, hir_id } = this.next_id();
                     hir::Ty { node: hir::TyKind::Tup(tys), id: node_id, hir_id, span }
                 };
+                let LoweredNodeId { node_id, hir_id } = this.next_id();
 
                 (
                     hir::GenericArgs {
                         args: hir_vec![GenericArg::Type(mk_tup(this, inputs, span))],
                         bindings: hir_vec![
                             hir::TypeBinding {
-                                id: this.next_id().node_id,
+                                id: node_id,
+                                hir_id,
                                 ident: Ident::from_str(FN_OUTPUT_NAME),
                                 ty: output
                                     .as_ref()
@@ -1957,7 +2008,7 @@ impl<'a> LoweringContext<'a> {
         )
     }
 
-    fn lower_local(&mut self, l: &Local) -> (P<hir::Local>, SmallVec<[hir::ItemId; 1]>) {
+    fn lower_local(&mut self, l: &Local) -> (hir::Local, SmallVec<[hir::ItemId; 1]>) {
         let LoweredNodeId { node_id, hir_id } = self.lower_node_id(l.id);
         let mut ids = SmallVec::<[hir::ItemId; 1]>::new();
         if self.sess.features_untracked().impl_trait_in_bindings {
@@ -1967,7 +2018,7 @@ impl<'a> LoweringContext<'a> {
             }
         }
         let parent_def_id = DefId::local(self.current_hir_id_owner.last().unwrap().0);
-        (P(hir::Local {
+        (hir::Local {
             id: node_id,
             hir_id,
             ty: l.ty
@@ -1984,7 +2035,7 @@ impl<'a> LoweringContext<'a> {
             span: l.span,
             attrs: l.attrs.clone(),
             source: hir::LocalSource::Normal,
-        }), ids)
+        }, ids)
     }
 
     fn lower_mutability(&mut self, m: Mutability) -> hir::Mutability {
@@ -2270,7 +2321,7 @@ impl<'a> LoweringContext<'a> {
                     let LoweredNodeId { node_id, hir_id } = this.next_id();
                     P(hir::Ty {
                         id: node_id,
-                        hir_id: hir_id,
+                        hir_id,
                         node: hir::TyKind::Tup(hir_vec![]),
                         span: *span,
                     })
@@ -2278,12 +2329,14 @@ impl<'a> LoweringContext<'a> {
             };
 
             // "<Output = T>"
+            let LoweredNodeId { node_id, hir_id } = this.next_id();
             let future_params = P(hir::GenericArgs {
                 args: hir_vec![],
                 bindings: hir_vec![hir::TypeBinding {
                     ident: Ident::from_str(FN_OUTPUT_NAME),
                     ty: output_ty,
-                    id: this.next_id().node_id,
+                    id: node_id,
+                    hir_id,
                     span,
                 }],
                 parenthesized: false,
@@ -2309,8 +2362,9 @@ impl<'a> LoweringContext<'a> {
             ];
 
             if let Some((name, span)) = bound_lifetime {
+                let LoweredNodeId { node_id, hir_id } = this.next_id();
                 bounds.push(hir::GenericBound::Outlives(
-                    hir::Lifetime { id: this.next_id().node_id, name, span }));
+                    hir::Lifetime { id: node_id, hir_id, name, span }));
             }
 
             hir::HirVec::from(bounds)
@@ -2377,8 +2431,11 @@ impl<'a> LoweringContext<'a> {
         span: Span,
         name: hir::LifetimeName,
     ) -> hir::Lifetime {
+        let LoweredNodeId { node_id, hir_id } = self.lower_node_id(id);
+
         hir::Lifetime {
-            id: self.lower_node_id(id).node_id,
+            id: node_id,
+            hir_id,
             span,
             name: name,
         }
@@ -2405,7 +2462,7 @@ impl<'a> LoweringContext<'a> {
             |this| this.lower_param_bounds(&param.bounds, itctx.reborrow()),
         );
 
-        match param.kind {
+        let (name, kind) = match param.kind {
             GenericParamKind::Lifetime => {
                 let was_collecting_in_band = self.is_collecting_in_band_lifetimes;
                 self.is_collecting_in_band_lifetimes = false;
@@ -2421,21 +2478,14 @@ impl<'a> LoweringContext<'a> {
                         | hir::LifetimeName::Static => hir::ParamName::Plain(lt.name.ident()),
                     hir::LifetimeName::Error => ParamName::Error,
                 };
-                let param = hir::GenericParam {
-                    id: lt.id,
-                    name: param_name,
-                    span: lt.span,
-                    pure_wrt_drop: attr::contains_name(&param.attrs, "may_dangle"),
-                    attrs: self.lower_attrs(&param.attrs),
-                    bounds,
-                    kind: hir::GenericParamKind::Lifetime {
-                        kind: hir::LifetimeParamKind::Explicit,
-                    }
+
+                let kind = hir::GenericParamKind::Lifetime {
+                    kind: hir::LifetimeParamKind::Explicit
                 };
 
                 self.is_collecting_in_band_lifetimes = was_collecting_in_band;
 
-                param
+                (param_name, kind)
             }
             GenericParamKind::Type { ref default, .. } => {
                 // Don't expose `Self` (recovered "keyword used as ident" parse error).
@@ -2455,24 +2505,36 @@ impl<'a> LoweringContext<'a> {
                                    .collect();
                 }
 
-                hir::GenericParam {
-                    id: self.lower_node_id(param.id).node_id,
-                    name: hir::ParamName::Plain(ident),
-                    pure_wrt_drop: attr::contains_name(&param.attrs, "may_dangle"),
-                    attrs: self.lower_attrs(&param.attrs),
-                    bounds,
-                    span: ident.span,
-                    kind: hir::GenericParamKind::Type {
-                        default: default.as_ref().map(|x| {
-                            self.lower_ty(x, ImplTraitContext::disallowed())
-                        }),
-                        synthetic: param.attrs.iter()
-                                              .filter(|attr| attr.check_name("rustc_synthetic"))
-                                              .map(|_| hir::SyntheticTyParamKind::ImplTrait)
-                                              .next(),
-                    }
-                }
+                let kind = hir::GenericParamKind::Type {
+                    default: default.as_ref().map(|x| {
+                        self.lower_ty(x, ImplTraitContext::disallowed())
+                    }),
+                    synthetic: param.attrs.iter()
+                                          .filter(|attr| attr.check_name("rustc_synthetic"))
+                                          .map(|_| hir::SyntheticTyParamKind::ImplTrait)
+                                          .next(),
+                };
+
+                (hir::ParamName::Plain(ident), kind)
+            }
+            GenericParamKind::Const { ref ty } => {
+                (hir::ParamName::Plain(param.ident), hir::GenericParamKind::Const {
+                    ty: self.lower_ty(&ty, ImplTraitContext::disallowed()),
+                })
             }
+        };
+
+        let LoweredNodeId { node_id, hir_id } = self.lower_node_id(param.id);
+
+        hir::GenericParam {
+            id: node_id,
+            hir_id,
+            name,
+            span: param.ident.span,
+            pure_wrt_drop: attr::contains_name(&param.attrs, "may_dangle"),
+            attrs: self.lower_attrs(&param.attrs),
+            bounds,
+            kind,
         }
     }
 
@@ -2546,8 +2608,11 @@ impl<'a> LoweringContext<'a> {
         self.with_anonymous_lifetime_mode(
             AnonymousLifetimeMode::ReportError,
             |this| {
+                let LoweredNodeId { node_id, hir_id } = this.lower_node_id(wc.id);
+
                 hir::WhereClause {
-                    id: this.lower_node_id(wc.id).node_id,
+                    id: node_id,
+                    hir_id,
                     predicates: wc.predicates
                         .iter()
                         .map(|predicate| this.lower_where_predicate(predicate))
@@ -2606,34 +2671,53 @@ impl<'a> LoweringContext<'a> {
                 ref lhs_ty,
                 ref rhs_ty,
                 span,
-            }) => hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
-                id: self.lower_node_id(id).node_id,
-                lhs_ty: self.lower_ty(lhs_ty, ImplTraitContext::disallowed()),
-                rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::disallowed()),
-                span,
-            }),
+            }) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(id);
+
+                hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
+                    id: node_id,
+                    hir_id,
+                    lhs_ty: self.lower_ty(lhs_ty, ImplTraitContext::disallowed()),
+                    rhs_ty: self.lower_ty(rhs_ty, ImplTraitContext::disallowed()),
+                    span,
+                })
+            },
         }
     }
 
     fn lower_variant_data(&mut self, vdata: &VariantData) -> hir::VariantData {
         match *vdata {
-            VariantData::Struct(ref fields, id) => hir::VariantData::Struct(
-                fields
-                    .iter()
-                    .enumerate()
-                    .map(|f| self.lower_struct_field(f))
-                    .collect(),
-                self.lower_node_id(id).node_id,
-            ),
-            VariantData::Tuple(ref fields, id) => hir::VariantData::Tuple(
-                fields
-                    .iter()
-                    .enumerate()
-                    .map(|f| self.lower_struct_field(f))
-                    .collect(),
-                self.lower_node_id(id).node_id,
-            ),
-            VariantData::Unit(id) => hir::VariantData::Unit(self.lower_node_id(id).node_id),
+            VariantData::Struct(ref fields, id) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(id);
+
+                hir::VariantData::Struct(
+                    fields
+                        .iter()
+                        .enumerate()
+                        .map(|f| self.lower_struct_field(f))
+                        .collect(),
+                    node_id,
+                    hir_id,
+                )
+            },
+            VariantData::Tuple(ref fields, id) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(id);
+
+                hir::VariantData::Tuple(
+                    fields
+                        .iter()
+                        .enumerate()
+                        .map(|f| self.lower_struct_field(f))
+                        .collect(),
+                    node_id,
+                    hir_id,
+                )
+            },
+            VariantData::Unit(id) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(id);
+
+                hir::VariantData::Unit(node_id, hir_id)
+            },
         }
     }
 
@@ -2673,9 +2757,12 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn lower_struct_field(&mut self, (index, f): (usize, &StructField)) -> hir::StructField {
+        let LoweredNodeId { node_id, hir_id } = self.lower_node_id(f.id);
+
         hir::StructField {
             span: f.span,
-            id: self.lower_node_id(f.id).node_id,
+            id: node_id,
+            hir_id,
             ident: match f.ident {
                 Some(ident) => ident,
                 // FIXME(jseyfried): positional field hygiene
@@ -2688,8 +2775,11 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn lower_field(&mut self, f: &Field) -> hir::Field {
+        let LoweredNodeId { node_id, hir_id } = self.next_id();
+
         hir::Field {
-            id: self.next_id().node_id,
+            id: node_id,
+            hir_id,
             ident: f.ident,
             expr: P(self.lower_expr(&f.expr)),
             span: f.span,
@@ -3205,7 +3295,7 @@ impl<'a> LoweringContext<'a> {
 
     /// Paths like the visibility path in `pub(super) use foo::{bar, baz}` are repeated
     /// many times in the HIR tree; for each occurrence, we need to assign distinct
-    /// node-ids. (See e.g., #56128.)
+    /// `NodeId`s. (See, e.g., #56128.)
     fn renumber_segment_ids(&mut self, path: &P<hir::Path>) -> P<hir::Path> {
         debug!("renumber_segment_ids(path = {:?})", path);
         let mut path = path.clone();
@@ -3447,11 +3537,13 @@ impl<'a> LoweringContext<'a> {
             if !def.legacy || attr::contains_name(&i.attrs, "macro_export") ||
                               attr::contains_name(&i.attrs, "rustc_doc_only_macro") {
                 let body = self.lower_token_stream(def.stream());
+                let hir_id = self.lower_node_id(i.id).hir_id;
                 self.exported_macros.push(hir::MacroDef {
                     name: ident.name,
                     vis,
                     attrs,
                     id: i.id,
+                    hir_id,
                     span: i.span,
                     body,
                     legacy: def.legacy,
@@ -3476,10 +3568,11 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn lower_foreign_item(&mut self, i: &ForeignItem) -> hir::ForeignItem {
-        let node_id = self.lower_node_id(i.id).node_id;
+        let LoweredNodeId { node_id, hir_id } = self.lower_node_id(i.id);
         let def_id = self.resolver.definitions().local_def_id(node_id);
         hir::ForeignItem {
             id: node_id,
+            hir_id,
             ident: i.ident,
             attrs: self.lower_attrs(&i.attrs),
             node: match i.node {
@@ -3616,9 +3709,11 @@ impl<'a> LoweringContext<'a> {
                             Some(Def::Local(id)) => id,
                             _ => p.id,
                         };
+                        let hir_id = self.lower_node_id(canonical_id).hir_id;
                         hir::PatKind::Binding(
                             self.lower_binding_mode(binding_mode),
                             canonical_id,
+                            hir_id,
                             ident,
                             sub.as_ref().map(|x| self.lower_pat(x)),
                         )
@@ -3669,14 +3764,19 @@ impl<'a> LoweringContext<'a> {
 
                 let fs = fields
                     .iter()
-                    .map(|f| Spanned {
-                        span: f.span,
-                        node: hir::FieldPat {
-                            id: self.next_id().node_id,
-                            ident: f.node.ident,
-                            pat: self.lower_pat(&f.node.pat),
-                            is_shorthand: f.node.is_shorthand,
-                        },
+                    .map(|f| {
+                        let LoweredNodeId { node_id, hir_id } = self.next_id();
+
+                        Spanned {
+                            span: f.span,
+                            node: hir::FieldPat {
+                                id: node_id,
+                                hir_id,
+                                ident: f.node.ident,
+                                pat: self.lower_pat(&f.node.pat),
+                                is_shorthand: f.node.is_shorthand,
+                            },
+                        }
                     })
                     .collect();
                 hir::PatKind::Struct(qpath, fs, etc)
@@ -3752,7 +3852,7 @@ impl<'a> LoweringContext<'a> {
                 hir::ExprKind::Call(f, args.iter().map(|x| self.lower_expr(x)).collect())
             }
             ExprKind::MethodCall(ref seg, ref args) => {
-                let hir_seg = self.lower_path_segment(
+                let hir_seg = P(self.lower_path_segment(
                     e.span,
                     seg,
                     ParamMode::Optional,
@@ -3760,7 +3860,7 @@ impl<'a> LoweringContext<'a> {
                     ParenthesizedGenericArgs::Err,
                     ImplTraitContext::disallowed(),
                     None,
-                );
+                ));
                 let args = args.iter().map(|x| self.lower_expr(x)).collect();
                 hir::ExprKind::MethodCall(hir_seg, seg.ident.span, args)
             }
@@ -3775,7 +3875,7 @@ impl<'a> LoweringContext<'a> {
                 let ohs = P(self.lower_expr(ohs));
                 hir::ExprKind::Unary(op, ohs)
             }
-            ExprKind::Lit(ref l) => hir::ExprKind::Lit(P((*l).clone())),
+            ExprKind::Lit(ref l) => hir::ExprKind::Lit((*l).clone()),
             ExprKind::Cast(ref expr, ref ty) => {
                 let expr = P(self.lower_expr(expr));
                 hir::ExprKind::Cast(expr, self.lower_ty(ty, ImplTraitContext::disallowed()))
@@ -3835,8 +3935,13 @@ impl<'a> LoweringContext<'a> {
             }),
             ExprKind::TryBlock(ref body) => {
                 self.with_catch_scope(body.id, |this| {
-                    let unstable_span =
-                        this.allow_internal_unstable(CompilerDesugaringKind::TryBlock, body.span);
+                    let unstable_span = this.mark_span_with_reason(
+                        CompilerDesugaringKind::TryBlock,
+                        body.span,
+                        Some(vec![
+                            Symbol::intern("try_trait"),
+                        ].into()),
+                    );
                     let mut block = this.lower_block(body, true).into_inner();
                     let tail = block.expr.take().map_or_else(
                         || {
@@ -4036,7 +4141,7 @@ impl<'a> LoweringContext<'a> {
                     node: if is_unit {
                         hir::ExprKind::Path(struct_path)
                     } else {
-                        hir::ExprKind::Struct(struct_path, fields, None)
+                        hir::ExprKind::Struct(P(struct_path), fields, None)
                     },
                     span: e.span,
                     attrs: e.attrs.clone(),
@@ -4108,13 +4213,13 @@ impl<'a> LoweringContext<'a> {
                 hir::ExprKind::InlineAsm(P(hir_asm), outputs, inputs)
             }
             ExprKind::Struct(ref path, ref fields, ref maybe_expr) => hir::ExprKind::Struct(
-                self.lower_qpath(
+                P(self.lower_qpath(
                     e.id,
                     &None,
                     path,
                     ParamMode::Optional,
                     ImplTraitContext::disallowed(),
-                ),
+                )),
                 fields.iter().map(|x| self.lower_field(x)).collect(),
                 maybe_expr.as_ref().map(|x| P(self.lower_expr(x))),
             ),
@@ -4268,9 +4373,10 @@ impl<'a> LoweringContext<'a> {
                 // expand <head>
                 let head = self.lower_expr(head);
                 let head_sp = head.span;
-                let desugared_span = self.allow_internal_unstable(
+                let desugared_span = self.mark_span_with_reason(
                     CompilerDesugaringKind::ForLoop,
                     head_sp,
+                    None,
                 );
 
                 let iter = self.str_to_ident("iter");
@@ -4331,10 +4437,13 @@ impl<'a> LoweringContext<'a> {
                         ThinVec::new(),
                     ))
                 };
-                let match_stmt = respan(
-                    head_sp,
-                    hir::StmtKind::Expr(match_expr, self.next_id().node_id)
-                );
+                let LoweredNodeId { node_id, hir_id } = self.next_id();
+                let match_stmt = hir::Stmt {
+                    id: node_id,
+                    hir_id,
+                    node: hir::StmtKind::Expr(match_expr),
+                    span: head_sp,
+                };
 
                 let next_expr = P(self.expr_ident(head_sp, next_ident, next_pat.id));
 
@@ -4357,10 +4466,13 @@ impl<'a> LoweringContext<'a> {
 
                 let body_block = self.with_loop_scope(e.id, |this| this.lower_block(body, false));
                 let body_expr = P(self.expr_block(body_block, ThinVec::new()));
-                let body_stmt = respan(
-                    body.span,
-                    hir::StmtKind::Expr(body_expr, self.next_id().node_id)
-                );
+                let LoweredNodeId { node_id, hir_id } = self.next_id();
+                let body_stmt = hir::Stmt {
+                    id: node_id,
+                    hir_id,
+                    node: hir::StmtKind::Expr(body_expr),
+                    span: body.span,
+                };
 
                 let loop_block = P(self.block_all(
                     e.span,
@@ -4427,8 +4539,13 @@ impl<'a> LoweringContext<'a> {
                 //                 return Try::from_error(From::from(err)),
                 // }
 
-                let unstable_span =
-                    self.allow_internal_unstable(CompilerDesugaringKind::QuestionMark, e.span);
+                let unstable_span = self.mark_span_with_reason(
+                    CompilerDesugaringKind::QuestionMark,
+                    e.span,
+                    Some(vec![
+                        Symbol::intern("try_trait")
+                    ].into()),
+                );
 
                 // `Try::into_result(<expr>)`
                 let discr = {
@@ -4533,26 +4650,26 @@ impl<'a> LoweringContext<'a> {
                 let (l, item_ids) = self.lower_local(l);
                 let mut ids: SmallVec<[hir::Stmt; 1]> = item_ids
                     .into_iter()
-                    .map(|item_id| Spanned {
-                        node: hir::StmtKind::Decl(
-                            P(Spanned {
-                                node: hir::DeclKind::Item(item_id),
-                                span: s.span,
-                            }),
-                            self.next_id().node_id,
-                        ),
-                        span: s.span,
+                    .map(|item_id| {
+                        let LoweredNodeId { node_id, hir_id } = self.next_id();
+
+                        hir::Stmt {
+                            id: node_id,
+                            hir_id,
+                            node: hir::StmtKind::Item(item_id),
+                            span: s.span,
+                        }
                     })
                     .collect();
-                ids.push(Spanned {
-                    node: hir::StmtKind::Decl(
-                        P(Spanned {
-                            node: hir::DeclKind::Local(l),
-                            span: s.span,
-                        }),
-                        self.lower_node_id(s.id).node_id,
-                    ),
-                    span: s.span,
+                ids.push({
+                    let LoweredNodeId { node_id, hir_id } = self.lower_node_id(s.id);
+
+                    hir::Stmt {
+                        id: node_id,
+                        hir_id,
+                        node: hir::StmtKind::Local(P(l)),
+                        span: s.span,
+                    }
                 });
                 return ids;
             },
@@ -4561,27 +4678,39 @@ impl<'a> LoweringContext<'a> {
                 let mut id = Some(s.id);
                 return self.lower_item_id(it)
                     .into_iter()
-                    .map(|item_id| Spanned {
-                        node: hir::StmtKind::Decl(
-                            P(Spanned {
-                                node: hir::DeclKind::Item(item_id),
-                                span: s.span,
-                            }),
-                            id.take()
-                              .map(|id| self.lower_node_id(id).node_id)
-                              .unwrap_or_else(|| self.next_id().node_id),
-                        ),
-                        span: s.span,
+                    .map(|item_id| {
+                        let LoweredNodeId { node_id, hir_id } = id.take()
+                          .map(|id| self.lower_node_id(id))
+                          .unwrap_or_else(|| self.next_id());
+
+                        hir::Stmt {
+                            id: node_id,
+                            hir_id,
+                            node: hir::StmtKind::Item(item_id),
+                            span: s.span,
+                        }
                     })
                     .collect();
             }
-            StmtKind::Expr(ref e) => Spanned {
-                node: hir::StmtKind::Expr(P(self.lower_expr(e)), self.lower_node_id(s.id).node_id),
-                span: s.span,
+            StmtKind::Expr(ref e) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(s.id);
+
+                hir::Stmt {
+                    id: node_id,
+                    hir_id,
+                    node: hir::StmtKind::Expr(P(self.lower_expr(e))),
+                    span: s.span,
+                }
             },
-            StmtKind::Semi(ref e) => Spanned {
-                node: hir::StmtKind::Semi(P(self.lower_expr(e)), self.lower_node_id(s.id).node_id),
-                span: s.span,
+            StmtKind::Semi(ref e) => {
+                let LoweredNodeId { node_id, hir_id } = self.lower_node_id(s.id);
+
+                hir::Stmt {
+                    id: node_id,
+                    hir_id,
+                    node: hir::StmtKind::Semi(P(self.lower_expr(e))),
+                    span: s.span,
+                }
             },
             StmtKind::Mac(..) => panic!("Shouldn't exist here"),
         }]
@@ -4692,8 +4821,11 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn field(&mut self, ident: Ident, expr: P<hir::Expr>, span: Span) -> hir::Field {
+        let LoweredNodeId { node_id, hir_id } = self.next_id();
+
         hir::Field {
-            id: self.next_id().node_id,
+            id: node_id,
+            hir_id,
             ident,
             span,
             expr,
@@ -4795,7 +4927,7 @@ impl<'a> LoweringContext<'a> {
     ) -> hir::Stmt {
         let LoweredNodeId { node_id, hir_id } = self.next_id();
 
-        let local = P(hir::Local {
+        let local = hir::Local {
             pat,
             ty: None,
             init: ex,
@@ -4804,9 +4936,15 @@ impl<'a> LoweringContext<'a> {
             span: sp,
             attrs: ThinVec::new(),
             source,
-        });
-        let decl = respan(sp, hir::DeclKind::Local(local));
-        respan(sp, hir::StmtKind::Decl(P(decl), self.next_id().node_id))
+        };
+
+        let LoweredNodeId { node_id, hir_id } = self.next_id();
+        hir::Stmt {
+            id: node_id,
+            hir_id,
+            node: hir::StmtKind::Local(P(local)),
+            span: sp
+        }
     }
 
     fn stmt_let(
@@ -4898,7 +5036,7 @@ impl<'a> LoweringContext<'a> {
         P(hir::Pat {
             id: node_id,
             hir_id,
-            node: hir::PatKind::Binding(bm, node_id, ident.with_span_pos(span), None),
+            node: hir::PatKind::Binding(bm, node_id, hir_id, ident.with_span_pos(span), None),
             span,
         })
     }
@@ -4984,8 +5122,10 @@ impl<'a> LoweringContext<'a> {
             // `'f`.
             AnonymousLifetimeMode::CreateParameter => {
                 let fresh_name = self.collect_fresh_in_band_lifetime(span);
+                let LoweredNodeId { node_id, hir_id } = self.next_id();
                 hir::Lifetime {
-                    id: self.next_id().node_id,
+                    id: node_id,
+                    hir_id,
                     span,
                     name: hir::LifetimeName::Param(fresh_name),
                 }
@@ -5085,8 +5225,11 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn new_implicit_lifetime(&mut self, span: Span) -> hir::Lifetime {
+        let LoweredNodeId { node_id, hir_id } = self.next_id();
+
         hir::Lifetime {
-            id: self.next_id().node_id,
+            id: node_id,
+            hir_id,
             span,
             name: hir::LifetimeName::Implicit,
         }
diff --git a/src/librustc/hir/map/blocks.rs b/src/librustc/hir/map/blocks.rs
index f61b8551927bb..6919628c76755 100644
--- a/src/librustc/hir/map/blocks.rs
+++ b/src/librustc/hir/map/blocks.rs
@@ -1,9 +1,9 @@
 //! This module provides a simplified abstraction for working with
-//! code blocks identified by their integer node-id.  In particular,
+//! code blocks identified by their integer `NodeId`. In particular,
 //! it captures a common set of attributes that all "function-like
-//! things" (represented by `FnLike` instances) share.  For example,
+//! things" (represented by `FnLike` instances) share. For example,
 //! all `FnLike` instances have a type signature (be it explicit or
-//! inferred).  And all `FnLike` instances have a body, i.e., the code
+//! inferred). And all `FnLike` instances have a body, i.e., the code
 //! that is run when the function-like thing it represents is invoked.
 //!
 //! With the above abstraction in place, one can treat the program
@@ -11,10 +11,10 @@
 //! nested within a uniquely determined `FnLike`), and users can ask
 //! for the `Code` associated with a particular NodeId.
 
-use hir as ast;
-use hir::map;
-use hir::{Expr, FnDecl, Node};
-use hir::intravisit::FnKind;
+use crate::hir as ast;
+use crate::hir::map;
+use crate::hir::{Expr, FnDecl, Node};
+use crate::hir::intravisit::FnKind;
 use syntax::ast::{Attribute, Ident, NodeId};
 use syntax_pos::Span;
 
diff --git a/src/librustc/hir/map/collector.rs b/src/librustc/hir/map/collector.rs
index ae9bb37842990..37552f18f4a08 100644
--- a/src/librustc/hir/map/collector.rs
+++ b/src/librustc/hir/map/collector.rs
@@ -1,18 +1,19 @@
 use super::*;
-use dep_graph::{DepGraph, DepKind, DepNodeIndex};
-use hir::def_id::{LOCAL_CRATE, CrateNum};
-use hir::intravisit::{Visitor, NestedVisitorMap};
+use crate::dep_graph::{DepGraph, DepKind, DepNodeIndex};
+use crate::hir;
+use crate::hir::def_id::{LOCAL_CRATE, CrateNum};
+use crate::hir::intravisit::{Visitor, NestedVisitorMap};
 use rustc_data_structures::svh::Svh;
-use ich::Fingerprint;
-use middle::cstore::CrateStore;
-use session::CrateDisambiguator;
-use session::Session;
+use crate::ich::Fingerprint;
+use crate::middle::cstore::CrateStore;
+use crate::session::CrateDisambiguator;
+use crate::session::Session;
 use std::iter::repeat;
 use syntax::ast::{NodeId, CRATE_NODE_ID};
 use syntax::source_map::SourceMap;
 use syntax_pos::Span;
 
-use ich::StableHashingContext;
+use crate::ich::StableHashingContext;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
 
 /// A Visitor that walks over the HIR and collects Nodes into a HIR map
@@ -28,6 +29,8 @@ pub(super) struct NodeCollector<'a, 'hir> {
     /// The parent of this node
     parent_node: NodeId,
 
+    parent_hir: hir::HirId,
+
     // These fields keep track of the currently relevant DepNodes during
     // the visitor's traversal.
     current_dep_node_owner: DefIndex,
@@ -45,14 +48,14 @@ pub(super) struct NodeCollector<'a, 'hir> {
     hir_body_nodes: Vec<(DefPathHash, Fingerprint)>,
 }
 
-fn input_dep_node_and_hash<'a, I>(
+fn input_dep_node_and_hash<I>(
     dep_graph: &DepGraph,
-    hcx: &mut StableHashingContext<'a>,
+    hcx: &mut StableHashingContext<'_>,
     dep_node: DepNode,
     input: I,
 ) -> (DepNodeIndex, Fingerprint)
 where
-    I: HashStable<StableHashingContext<'a>>,
+    I: for<'a> HashStable<StableHashingContext<'a>>,
 {
     let dep_node_index = dep_graph.input_task(dep_node, &mut *hcx, &input).1;
 
@@ -67,15 +70,15 @@ where
     (dep_node_index, hash)
 }
 
-fn alloc_hir_dep_nodes<'a, I>(
+fn alloc_hir_dep_nodes<I>(
     dep_graph: &DepGraph,
-    hcx: &mut StableHashingContext<'a>,
+    hcx: &mut StableHashingContext<'_>,
     def_path_hash: DefPathHash,
     item_like: I,
     hir_body_nodes: &mut Vec<(DefPathHash, Fingerprint)>,
 ) -> (DepNodeIndex, DepNodeIndex)
 where
-    I: HashStable<StableHashingContext<'a>>,
+    I: for<'a> HashStable<StableHashingContext<'a>>,
 {
     let sig = dep_graph.input_task(
         def_path_hash.to_dep_node(DepKind::Hir),
@@ -145,6 +148,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
             source_map: sess.source_map(),
             map: repeat(None).take(sess.current_node_id_count()).collect(),
             parent_node: CRATE_NODE_ID,
+            parent_hir: hir::CRATE_HIR_ID,
             current_signature_dep_index: root_mod_sig_dep_index,
             current_full_dep_index: root_mod_full_dep_index,
             current_dep_node_owner: CRATE_DEF_INDEX,
@@ -156,6 +160,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         };
         collector.insert_entry(CRATE_NODE_ID, Entry {
             parent: CRATE_NODE_ID,
+            parent_hir: hir::CRATE_HIR_ID,
             dep_node: root_mod_sig_dep_index,
             node: Node::Crate,
         });
@@ -226,6 +231,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
     fn insert(&mut self, span: Span, id: NodeId, node: Node<'hir>) {
         let entry = Entry {
             parent: self.parent_node,
+            parent_hir: self.parent_hir,
             dep_node: if self.currently_in_body {
                 self.current_full_dep_index
             } else {
@@ -247,7 +253,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
                     None => format!("{:?}", node)
                 };
 
-                let forgot_str = if hir_id == ::hir::DUMMY_HIR_ID {
+                let forgot_str = if hir_id == crate::hir::DUMMY_HIR_ID {
                     format!("\nMaybe you forgot to lower the node id {:?}?", id)
                 } else {
                     String::new()
@@ -280,7 +286,7 @@ impl<'a, 'hir> NodeCollector<'a, 'hir> {
         self.parent_node = parent_node;
     }
 
-    fn with_dep_node_owner<T: HashStable<StableHashingContext<'a>>,
+    fn with_dep_node_owner<T: for<'b> HashStable<StableHashingContext<'b>>,
                            F: FnOnce(&mut Self)>(&mut self,
                                                  dep_node_owner: DefIndex,
                                                  item_like: &T,
@@ -426,7 +432,7 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
     }
 
     fn visit_stmt(&mut self, stmt: &'hir Stmt) {
-        let id = stmt.node.id();
+        let id = stmt.id;
         self.insert(stmt.span, id, Node::Stmt(stmt));
 
         self.with_parent(id, |this| {
diff --git a/src/librustc/hir/map/def_collector.rs b/src/librustc/hir/map/def_collector.rs
index bc0a64ae7c5d8..8fe10a85ef380 100644
--- a/src/librustc/hir/map/def_collector.rs
+++ b/src/librustc/hir/map/def_collector.rs
@@ -1,6 +1,6 @@
-use hir::map::definitions::*;
-use hir::def_id::{CRATE_DEF_INDEX, DefIndex, DefIndexAddressSpace};
-use session::CrateDisambiguator;
+use crate::hir::map::definitions::*;
+use crate::hir::def_id::{CRATE_DEF_INDEX, DefIndex, DefIndexAddressSpace};
+use crate::session::CrateDisambiguator;
 
 use syntax::ast::*;
 use syntax::ext::hygiene::Mark;
@@ -10,9 +10,9 @@ use syntax::symbol::Symbol;
 use syntax::parse::token::{self, Token};
 use syntax_pos::Span;
 
-use hir::map::{ITEM_LIKE_SPACE, REGULAR_SPACE};
+use crate::hir::map::{ITEM_LIKE_SPACE, REGULAR_SPACE};
 
-/// Creates def ids for nodes in the AST.
+/// Creates `DefId`s for nodes in the AST.
 pub struct DefCollector<'a> {
     definitions: &'a mut Definitions,
     parent_def: Option<DefIndex>,
@@ -120,10 +120,10 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
         let def_data = match i.node {
             ItemKind::Impl(..) => DefPathData::Impl,
             ItemKind::Trait(..) => DefPathData::Trait(i.ident.as_interned_str()),
+            ItemKind::TraitAlias(..) => DefPathData::TraitAlias(i.ident.as_interned_str()),
             ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..) |
-            ItemKind::TraitAlias(..) | ItemKind::Existential(..) |
-            ItemKind::ExternCrate(..) | ItemKind::ForeignMod(..) | ItemKind::Ty(..) =>
-                DefPathData::TypeNs(i.ident.as_interned_str()),
+            ItemKind::Existential(..) | ItemKind::ExternCrate(..) | ItemKind::ForeignMod(..) |
+            ItemKind::Ty(..) => DefPathData::TypeNs(i.ident.as_interned_str()),
             ItemKind::Mod(..) if i.ident == keywords::Invalid.ident() => {
                 return visit::walk_item(self, i);
             }
@@ -218,6 +218,7 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
         let def_path_data = match param.kind {
             GenericParamKind::Lifetime { .. } => DefPathData::LifetimeParam(name),
             GenericParamKind::Type { .. } => DefPathData::TypeParam(name),
+            GenericParamKind::Const { .. } => DefPathData::ConstParam(name),
         };
         self.create_def(param.id, def_path_data, REGULAR_SPACE, param.ident.span);
 
diff --git a/src/librustc/hir/map/definitions.rs b/src/librustc/hir/map/definitions.rs
index 6b707dd2dcc80..f454d691d4188 100644
--- a/src/librustc/hir/map/definitions.rs
+++ b/src/librustc/hir/map/definitions.rs
@@ -1,18 +1,18 @@
-//! For each definition, we track the following data.  A definition
-//! here is defined somewhat circularly as "something with a def-id",
+//! For each definition, we track the following data. A definition
+//! here is defined somewhat circularly as "something with a `DefId`",
 //! but it generally corresponds to things like structs, enums, etc.
 //! There are also some rather random cases (like const initializer
 //! expressions) that are mostly just leftovers.
 
-use hir;
-use hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE, DefIndexAddressSpace,
+use crate::hir;
+use crate::hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE, DefIndexAddressSpace,
                   CRATE_DEF_INDEX};
-use ich::Fingerprint;
+use crate::ich::Fingerprint;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::{IndexVec};
 use rustc_data_structures::stable_hasher::StableHasher;
 use serialize::{Encodable, Decodable, Encoder, Decoder};
-use session::CrateDisambiguator;
+use crate::session::CrateDisambiguator;
 use std::borrow::Borrow;
 use std::fmt::Write;
 use std::hash::Hash;
@@ -20,7 +20,7 @@ use syntax::ast;
 use syntax::ext::hygiene::Mark;
 use syntax::symbol::{Symbol, InternedString};
 use syntax_pos::{Span, DUMMY_SP};
-use util::nodemap::NodeMap;
+use crate::util::nodemap::NodeMap;
 
 /// The DefPathTable maps DefIndexes to DefKeys and vice versa.
 /// Internally the DefPathTable holds a tree of DefKeys, where each DefKey
@@ -163,10 +163,10 @@ pub struct Definitions {
 /// any) with a `DisambiguatedDefPathData`.
 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
 pub struct DefKey {
-    /// Parent path.
+    /// The parent path.
     pub parent: Option<DefIndex>,
 
-    /// Identifier of this node.
+    /// The identifier of this node.
     pub disambiguated_data: DisambiguatedDefPathData,
 }
 
@@ -207,12 +207,12 @@ impl DefKey {
     }
 }
 
-/// Pair of `DefPathData` and an integer disambiguator. The integer is
+/// A pair of `DefPathData` and an integer disambiguator. The integer is
 /// normally 0, but in the event that there are multiple defs with the
 /// same `parent` and `data`, we use this field to disambiguate
 /// between them. This introduces some artificial ordering dependency
 /// but means that if you have (e.g.) two impls for the same type in
-/// the same module, they do get distinct def-ids.
+/// the same module, they do get distinct `DefId`s.
 #[derive(Clone, PartialEq, Debug, Hash, RustcEncodable, RustcDecodable)]
 pub struct DisambiguatedDefPathData {
     pub data: DefPathData,
@@ -221,10 +221,10 @@ pub struct DisambiguatedDefPathData {
 
 #[derive(Clone, Debug, Hash, RustcEncodable, RustcDecodable)]
 pub struct DefPath {
-    /// the path leading from the crate root to the item
+    /// The path leading from the crate root to the item.
     pub data: Vec<DisambiguatedDefPathData>,
 
-    /// what krate root is this path relative to?
+    /// The crate root this path is relative to.
     pub krate: CrateNum,
 }
 
@@ -260,9 +260,9 @@ impl DefPath {
         DefPath { data: data, krate: krate }
     }
 
-    /// Returns a string representation of the DefPath without
+    /// Returns a string representation of the `DefPath` without
     /// the crate-prefix. This method is useful if you don't have
-    /// a TyCtxt available.
+    /// a `TyCtxt` available.
     pub fn to_string_no_crate(&self) -> String {
         let mut s = String::with_capacity(self.data.len() * 16);
 
@@ -277,7 +277,7 @@ impl DefPath {
         s
     }
 
-    /// Return filename friendly string of the DefPah with the
+    /// Returns a filename-friendly string for the `DefPath`, with the
     /// crate-prefix.
     pub fn to_string_friendly<F>(&self, crate_imported_name: F) -> String
         where F: FnOnce(CrateNum) -> Symbol
@@ -302,9 +302,9 @@ impl DefPath {
         s
     }
 
-    /// Return filename friendly string of the DefPah without
+    /// Returns a filename-friendly string of the `DefPath`, without
     /// the crate-prefix. This method is useful if you don't have
-    /// a TyCtxt available.
+    /// a `TyCtxt` available.
     pub fn to_filename_friendly_no_crate(&self) -> String {
         let mut s = String::with_capacity(self.data.len() * 16);
 
@@ -356,10 +356,12 @@ pub enum DefPathData {
     /// A closure expression
     ClosureExpr,
     // Subportions of items
-    /// A type parameter (generic parameter)
+    /// A type (generic) parameter
     TypeParam(InternedString),
-    /// A lifetime definition
+    /// A lifetime (generic) parameter
     LifetimeParam(InternedString),
+    /// A const (generic) parameter
+    ConstParam(InternedString),
     /// A variant of a enum
     EnumVariant(InternedString),
     /// A struct field
@@ -373,7 +375,9 @@ pub enum DefPathData {
     /// GlobalMetaData identifies a piece of crate metadata that is global to
     /// a whole crate (as opposed to just one item). GlobalMetaData components
     /// are only supposed to show up right below the crate root.
-    GlobalMetaData(InternedString)
+    GlobalMetaData(InternedString),
+    /// A trait alias.
+    TraitAlias(InternedString),
 }
 
 #[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug,
@@ -390,18 +394,18 @@ impl Borrow<Fingerprint> for DefPathHash {
 }
 
 impl Definitions {
-    /// Create new empty definition map.
+    /// Creates new empty definition map.
     ///
-    /// The DefIndex returned from a new Definitions are as follows:
-    /// 1. At DefIndexAddressSpace::Low,
+    /// The `DefIndex` returned from a new `Definitions` are as follows:
+    /// 1. At `DefIndexAddressSpace::Low`,
     ///     CRATE_ROOT has index 0:0, and then new indexes are allocated in
     ///     ascending order.
-    /// 2. At DefIndexAddressSpace::High,
-    ///     the first FIRST_FREE_HIGH_DEF_INDEX indexes are reserved for
-    ///     internal use, then 1:FIRST_FREE_HIGH_DEF_INDEX are allocated in
+    /// 2. At `DefIndexAddressSpace::High`,
+    ///     the first `FIRST_FREE_HIGH_DEF_INDEX` indexes are reserved for
+    ///     internal use, then `1:FIRST_FREE_HIGH_DEF_INDEX` are allocated in
     ///     ascending order.
-    ///
-    /// FIXME: there is probably a better place to put this comment.
+    //
+    // FIXME: there is probably a better place to put this comment.
     pub fn new() -> Self {
         Self::default()
     }
@@ -410,7 +414,7 @@ impl Definitions {
         &self.table
     }
 
-    /// Get the number of definitions.
+    /// Gets the number of definitions.
     pub fn def_index_counts_lo_hi(&self) -> (usize, usize) {
         (self.table.index_to_key[DefIndexAddressSpace::Low.index()].len(),
          self.table.index_to_key[DefIndexAddressSpace::High.index()].len())
@@ -465,6 +469,21 @@ impl Definitions {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    #[inline]
+    pub fn as_local_hir_id(&self, def_id: DefId) -> Option<hir::HirId> {
+        if def_id.krate == LOCAL_CRATE {
+            let hir_id = self.def_index_to_hir_id(def_id.index);
+            if hir_id != hir::DUMMY_HIR_ID {
+                Some(hir_id)
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
     #[inline]
     pub fn node_to_hir_id(&self, node_id: ast::NodeId) -> hir::HirId {
         self.node_to_hir_id[node_id]
@@ -478,8 +497,8 @@ impl Definitions {
         self.node_to_hir_id[node_id]
     }
 
-    /// Retrieve the span of the given `DefId` if `DefId` is in the local crate, the span exists and
-    /// it's not DUMMY_SP
+    /// Retrieves the span of the given `DefId` if `DefId` is in the local crate, the span exists
+    /// and it's not `DUMMY_SP`.
     #[inline]
     pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
         if def_id.krate == LOCAL_CRATE {
@@ -489,7 +508,7 @@ impl Definitions {
         }
     }
 
-    /// Add a definition with a parent definition.
+    /// Adds a root definition (no parent).
     pub fn create_root_def(&mut self,
                            crate_name: &str,
                            crate_disambiguator: CrateDisambiguator)
@@ -587,7 +606,7 @@ impl Definitions {
         index
     }
 
-    /// Initialize the ast::NodeId to HirId mapping once it has been generated during
+    /// Initialize the `ast::NodeId` to `HirId` mapping once it has been generated during
     /// AST to HIR lowering.
     pub fn init_node_id_to_hir_id_mapping(&mut self,
                                           mapping: IndexVec<ast::NodeId, hir::HirId>) {
@@ -615,6 +634,7 @@ impl DefPathData {
         match *self {
             TypeNs(name) |
             Trait(name) |
+            TraitAlias(name) |
             AssocTypeInTrait(name) |
             AssocTypeInImpl(name) |
             AssocExistentialInImpl(name) |
@@ -623,6 +643,7 @@ impl DefPathData {
             MacroDef(name) |
             TypeParam(name) |
             LifetimeParam(name) |
+            ConstParam(name) |
             EnumVariant(name) |
             Field(name) |
             GlobalMetaData(name) => Some(name),
@@ -642,6 +663,7 @@ impl DefPathData {
         let s = match *self {
             TypeNs(name) |
             Trait(name) |
+            TraitAlias(name) |
             AssocTypeInTrait(name) |
             AssocTypeInImpl(name) |
             AssocExistentialInImpl(name) |
@@ -650,6 +672,7 @@ impl DefPathData {
             MacroDef(name) |
             TypeParam(name) |
             LifetimeParam(name) |
+            ConstParam(name) |
             EnumVariant(name) |
             Field(name) |
             GlobalMetaData(name) => {
diff --git a/src/librustc/hir/map/hir_id_validator.rs b/src/librustc/hir/map/hir_id_validator.rs
index 91c8c29144406..2c3ff4c9b5c05 100644
--- a/src/librustc/hir/map/hir_id_validator.rs
+++ b/src/librustc/hir/map/hir_id_validator.rs
@@ -1,7 +1,7 @@
-use hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
-use hir::{self, intravisit, HirId, ItemLocalId};
+use crate::hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
+use crate::hir::{self, intravisit, HirId, ItemLocalId};
 use syntax::ast::NodeId;
-use hir::itemlikevisit::ItemLikeVisitor;
+use crate::hir::itemlikevisit::ItemLikeVisitor;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{Lock, ParallelIterator, par_iter};
 
diff --git a/src/librustc/hir/map/mod.rs b/src/librustc/hir/map/mod.rs
index 869baef1f5afc..e933e4b7180c4 100644
--- a/src/librustc/hir/map/mod.rs
+++ b/src/librustc/hir/map/mod.rs
@@ -3,11 +3,11 @@ pub use self::def_collector::{DefCollector, MacroInvocationData};
 pub use self::definitions::{Definitions, DefKey, DefPath, DefPathData,
                             DisambiguatedDefPathData, DefPathHash};
 
-use dep_graph::{DepGraph, DepNode, DepKind, DepNodeIndex};
+use crate::dep_graph::{DepGraph, DepNode, DepKind, DepNodeIndex};
 
-use hir::def_id::{CRATE_DEF_INDEX, DefId, LocalDefId, DefIndexAddressSpace};
+use crate::hir::def_id::{CRATE_DEF_INDEX, DefId, LocalDefId, DefIndexAddressSpace};
 
-use middle::cstore::CrateStoreDyn;
+use crate::middle::cstore::CrateStoreDyn;
 
 use rustc_target::spec::abi::Abi;
 use rustc_data_structures::svh::Svh;
@@ -17,15 +17,15 @@ use syntax::source_map::Spanned;
 use syntax::ext::base::MacroKind;
 use syntax_pos::{Span, DUMMY_SP};
 
-use hir::*;
-use hir::itemlikevisit::ItemLikeVisitor;
-use hir::print::Nested;
-use util::nodemap::FxHashMap;
-use util::common::time;
+use crate::hir::*;
+use crate::hir::itemlikevisit::ItemLikeVisitor;
+use crate::hir::print::Nested;
+use crate::util::nodemap::FxHashMap;
+use crate::util::common::time;
 
 use std::io;
 use std::result::Result::Err;
-use ty::TyCtxt;
+use crate::ty::TyCtxt;
 
 pub mod blocks;
 mod collector;
@@ -36,10 +36,11 @@ mod hir_id_validator;
 pub const ITEM_LIKE_SPACE: DefIndexAddressSpace = DefIndexAddressSpace::Low;
 pub const REGULAR_SPACE: DefIndexAddressSpace = DefIndexAddressSpace::High;
 
-/// Represents an entry and its parent NodeId.
+/// Represents an entry and its parent `NodeId`.
 #[derive(Copy, Clone, Debug)]
 pub struct Entry<'hir> {
     parent: NodeId,
+    parent_hir: HirId,
     dep_node: DepNodeIndex,
     node: Node<'hir>,
 }
@@ -126,9 +127,9 @@ impl<'hir> Entry<'hir> {
         }
     }
 
-    fn is_body_owner(self, node_id: NodeId) -> bool {
+    fn is_body_owner(self, hir_id: HirId) -> bool {
         match self.associated_body() {
-            Some(b) => b.node_id == node_id,
+            Some(b) => b.hir_id == hir_id,
             None => false,
         }
     }
@@ -161,8 +162,7 @@ impl Forest {
     }
 }
 
-/// Represents a mapping from Node IDs to AST elements and their parent
-/// Node IDs
+/// Represents a mapping from `NodeId`s to AST elements and their parent `NodeId`s.
 #[derive(Clone)]
 pub struct Map<'hir> {
     /// The backing storage for all the AST nodes.
@@ -208,6 +208,12 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn read_by_hir_id(&self, hir_id: HirId) {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.read(node_id);
+    }
+
     #[inline]
     pub fn definitions(&self) -> &'hir Definitions {
         self.definitions
@@ -224,6 +230,11 @@ impl<'hir> Map<'hir> {
         })
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn def_path_from_hir_id(&self, id: HirId) -> DefPath {
+        self.def_path(self.local_def_id_from_hir_id(id))
+    }
+
     pub fn def_path(&self, def_id: DefId) -> DefPath {
         assert!(def_id.is_local());
         self.definitions.def_path(def_id.index)
@@ -237,6 +248,23 @@ impl<'hir> Map<'hir> {
         })
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    #[inline]
+    pub fn local_def_id_from_hir_id(&self, hir_id: HirId) -> DefId {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.opt_local_def_id(node_id).unwrap_or_else(|| {
+            bug!("local_def_id_from_hir_id: no entry for `{:?}`, which has a map of `{:?}`",
+                 hir_id, self.find_entry(node_id))
+        })
+    }
+
+    // FIXME(@ljedrz): replace the NodeId variant
+    #[inline]
+    pub fn opt_local_def_id_from_hir_id(&self, hir_id: HirId) -> Option<DefId> {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.definitions.opt_local_def_id(node_id)
+    }
+
     #[inline]
     pub fn opt_local_def_id(&self, node: NodeId) -> Option<DefId> {
         self.definitions.opt_local_def_id(node)
@@ -247,6 +275,12 @@ impl<'hir> Map<'hir> {
         self.definitions.as_local_node_id(def_id)
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    #[inline]
+    pub fn as_local_hir_id(&self, def_id: DefId) -> Option<HirId> {
+        self.definitions.as_local_hir_id(def_id)
+    }
+
     #[inline]
     pub fn hir_to_node_id(&self, hir_id: HirId) -> NodeId {
         self.hir_to_node_id[&hir_id]
@@ -336,8 +370,12 @@ impl<'hir> Map<'hir> {
                 let def_id = self.local_def_id(variant.node.data.id());
                 Some(Def::Variant(def_id))
             }
-            Node::Field(_) |
+            Node::StructCtor(variant) => {
+                let def_id = self.local_def_id(variant.id());
+                Some(Def::StructCtor(def_id, def::CtorKind::from_hir(variant)))
+            }
             Node::AnonConst(_) |
+            Node::Field(_) |
             Node::Expr(_) |
             Node::Stmt(_) |
             Node::PathSegment(_) |
@@ -345,7 +383,6 @@ impl<'hir> Map<'hir> {
             Node::TraitRef(_) |
             Node::Pat(_) |
             Node::Binding(_) |
-            Node::StructCtor(_) |
             Node::Lifetime(_) |
             Node::Visibility(_) |
             Node::Block(_) |
@@ -361,11 +398,18 @@ impl<'hir> Map<'hir> {
                 Some(match param.kind {
                     GenericParamKind::Lifetime { .. } => Def::Local(param.id),
                     GenericParamKind::Type { .. } => Def::TyParam(self.local_def_id(param.id)),
+                    GenericParamKind::Const { .. } => Def::ConstParam(self.local_def_id(param.id)),
                 })
             }
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn describe_def_by_hir_id(&self, hir_id: HirId) -> Option<Def> {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.describe_def(node_id)
+    }
+
     fn entry_count(&self) -> usize {
         self.map.len()
     }
@@ -395,7 +439,7 @@ impl<'hir> Map<'hir> {
     }
 
     pub fn body(&self, id: BodyId) -> &'hir Body {
-        self.read(id.node_id);
+        self.read_by_hir_id(id.hir_id);
 
         // N.B., intentionally bypass `self.forest.krate()` so that we
         // do not trigger a read of the whole krate here
@@ -410,12 +454,19 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn fn_decl_by_hir_id(&self, hir_id: HirId) -> Option<FnDecl> {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.fn_decl(node_id)
+    }
+
     /// Returns the `NodeId` that corresponds to the definition of
     /// which this is the body of, i.e., a `fn`, `const` or `static`
     /// item (possibly associated), a closure, or a `hir::AnonConst`.
-    pub fn body_owner(&self, BodyId { node_id }: BodyId) -> NodeId {
+    pub fn body_owner(&self, BodyId { hir_id }: BodyId) -> NodeId {
+        let node_id = self.hir_to_node_id(hir_id);
         let parent = self.get_parent_node(node_id);
-        assert!(self.map[parent.as_usize()].map_or(false, |e| e.is_body_owner(node_id)));
+        assert!(self.map[parent.as_usize()].map_or(false, |e| e.is_body_owner(hir_id)));
         parent
     }
 
@@ -423,7 +474,7 @@ impl<'hir> Map<'hir> {
         self.local_def_id(self.body_owner(id))
     }
 
-    /// Given a node id, returns the `BodyId` associated with it,
+    /// Given a `NodeId`, returns the `BodyId` associated with it,
     /// if the node is a body owner, otherwise returns `None`.
     pub fn maybe_body_owned_by(&self, id: NodeId) -> Option<BodyId> {
         if let Some(entry) = self.find_entry(id) {
@@ -439,6 +490,12 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn maybe_body_owned_by_by_hir_id(&self, id: HirId) -> Option<BodyId> {
+        let node_id = self.hir_to_node_id(id);
+        self.maybe_body_owned_by(node_id)
+    }
+
     /// Given a body owner's id, returns the `BodyId` associated with it.
     pub fn body_owned_by(&self, id: NodeId) -> BodyId {
         self.maybe_body_owned_by(id).unwrap_or_else(|| {
@@ -455,14 +512,29 @@ impl<'hir> Map<'hir> {
             Node::AnonConst(_) => {
                 BodyOwnerKind::Const
             }
+            Node::Variant(&Spanned { node: VariantKind { data: VariantData::Tuple(..), .. }, .. }) |
+            Node::StructCtor(..) |
+            Node::Item(&Item { node: ItemKind::Fn(..), .. }) |
+            Node::TraitItem(&TraitItem { node: TraitItemKind::Method(..), .. }) |
+            Node::ImplItem(&ImplItem { node: ImplItemKind::Method(..), .. }) => {
+                BodyOwnerKind::Fn
+            }
             Node::Item(&Item { node: ItemKind::Static(_, m, _), .. }) => {
                 BodyOwnerKind::Static(m)
             }
-            // Default to function if it's not a constant or static.
-            _ => BodyOwnerKind::Fn
+            Node::Expr(&Expr { node: ExprKind::Closure(..), .. }) => {
+                BodyOwnerKind::Closure
+            }
+            node => bug!("{:#?} is not a body node", node),
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn body_owner_kind_by_hir_id(&self, id: HirId) -> BodyOwnerKind {
+        let node_id = self.hir_to_node_id(id);
+        self.body_owner_kind(node_id)
+    }
+
     pub fn ty_param_owner(&self, id: NodeId) -> NodeId {
         match self.get(id) {
             Node::Item(&Item { node: ItemKind::Trait(..), .. }) => id,
@@ -499,7 +571,7 @@ impl<'hir> Map<'hir> {
         self.trait_auto_impl(trait_did).is_some()
     }
 
-    /// Get the attributes on the krate. This is preferable to
+    /// Gets the attributes on the crate. This is preferable to
     /// invoking `krate.attrs` because it registers a tighter
     /// dep-graph access.
     pub fn krate_attrs(&self) -> &'hir [ast::Attribute] {
@@ -509,6 +581,21 @@ impl<'hir> Map<'hir> {
         &self.forest.krate.attrs
     }
 
+    pub fn get_module(&self, module: DefId) -> (&'hir Mod, Span, NodeId)
+    {
+        let node_id = self.as_local_node_id(module).unwrap();
+        self.read(node_id);
+        match self.find_entry(node_id).unwrap().node {
+            Node::Item(&Item {
+                span,
+                node: ItemKind::Mod(ref m),
+                ..
+            }) => (m, span, node_id),
+            Node::Crate => (&self.forest.krate.module, self.forest.krate.span, node_id),
+            _ => panic!("not a module")
+        }
+    }
+
     pub fn visit_item_likes_in_module<V>(&self, module: DefId, visitor: &mut V)
         where V: ItemLikeVisitor<'hir>
     {
@@ -542,6 +629,12 @@ impl<'hir> Map<'hir> {
         self.find(id).unwrap_or_else(|| bug!("couldn't find node id {} in the AST map", id))
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_by_hir_id(&self, id: HirId) -> Node<'hir> {
+        let node_id = self.hir_to_node_id(id);
+        self.get(node_id)
+    }
+
     pub fn get_if_local(&self, id: DefId) -> Option<Node<'hir>> {
         self.as_local_node_id(id).map(|id| self.get(id)) // read recorded by `get`
     }
@@ -573,8 +666,7 @@ impl<'hir> Map<'hir> {
         self.get_generics(id).map(|generics| generics.span).filter(|sp| *sp != DUMMY_SP)
     }
 
-    /// Retrieve the Node corresponding to `id`, returning None if
-    /// cannot be found.
+    /// Retrieves the `Node` corresponding to `id`, returning `None` if cannot be found.
     pub fn find(&self, id: NodeId) -> Option<Node<'hir>> {
         let result = self.find_entry(id).and_then(|entry| {
             if let Node::Crate = entry.node {
@@ -589,6 +681,12 @@ impl<'hir> Map<'hir> {
         result
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn find_by_hir_id(&self, hir_id: HirId) -> Option<Node<'hir>> {
+        let node_id = self.hir_to_node_id(hir_id);
+        self.find(node_id)
+    }
+
     /// Similar to `get_parent`; returns the parent node-id, or own `id` if there is
     /// no parent. Note that the parent may be `CRATE_NODE_ID`, which is not itself
     /// present in the map -- so passing the return value of get_parent_node to
@@ -597,8 +695,8 @@ impl<'hir> Map<'hir> {
     /// returns the enclosing item. Note that this might not be the actual parent
     /// node in the AST - some kinds of nodes are not in the map and these will
     /// never appear as the parent_node. So you can always walk the `parent_nodes`
-    /// from a node to the root of the ast (unless you get the same id back here
-    /// that can happen if the id is not in the map itself or is just weird).
+    /// from a node to the root of the ast (unless you get the same ID back here
+    /// that can happen if the ID is not in the map itself or is just weird).
     pub fn get_parent_node(&self, id: NodeId) -> NodeId {
         if self.dep_graph.is_fully_enabled() {
             let hir_id_owner = self.node_to_hir_id(id).owner;
@@ -609,6 +707,13 @@ impl<'hir> Map<'hir> {
         self.find_entry(id).and_then(|x| x.parent_node()).unwrap_or(id)
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_parent_node_by_hir_id(&self, id: HirId) -> HirId {
+        let node_id = self.hir_to_node_id(id);
+        let parent_node_id = self.get_parent_node(node_id);
+        self.node_to_hir_id(parent_node_id)
+    }
+
     /// Check if the node is an argument. An argument is a local variable whose
     /// immediate parent is an item or a closure.
     pub fn is_argument(&self, id: NodeId) -> bool {
@@ -632,7 +737,7 @@ impl<'hir> Map<'hir> {
 
     /// If there is some error when walking the parents (e.g., a node does not
     /// have a parent in the map or a node can't be found), then we return the
-    /// last good node id we found. Note that reaching the crate root (`id == 0`),
+    /// last good `NodeId` we found. Note that reaching the crate root (`id == 0`),
     /// is not an error, since items in the crate module have the crate root as
     /// parent.
     fn walk_parent_nodes<F, F2>(&self,
@@ -668,7 +773,7 @@ impl<'hir> Map<'hir> {
         }
     }
 
-    /// Retrieve the `NodeId` for `id`'s enclosing method, unless there's a
+    /// Retrieves the `NodeId` for `id`'s enclosing method, unless there's a
     /// `while` or `loop` before reaching it, as block tail returns are not
     /// available in them.
     ///
@@ -716,7 +821,7 @@ impl<'hir> Map<'hir> {
         self.walk_parent_nodes(id, match_fn, match_non_returning_block).ok()
     }
 
-    /// Retrieve the `NodeId` for `id`'s parent item, or `id` itself if no
+    /// Retrieves the `NodeId` for `id`'s parent item, or `id` itself if no
     /// parent item is in this map. The "parent item" is the closest parent node
     /// in the HIR which is recorded by the map and is an item, either an item
     /// in a module, trait, or impl.
@@ -733,12 +838,25 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_parent_item(&self, id: HirId) -> HirId {
+        let node_id = self.hir_to_node_id(id);
+        let parent_node_id = self.get_parent(node_id);
+        self.node_to_hir_id(parent_node_id)
+    }
+
     /// Returns the `DefId` of `id`'s nearest module parent, or `id` itself if no
     /// module parent is in this map.
     pub fn get_module_parent(&self, id: NodeId) -> DefId {
         self.local_def_id(self.get_module_parent_node(id))
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_module_parent_by_hir_id(&self, id: HirId) -> DefId {
+        let node_id = self.hir_to_node_id(id);
+        self.get_module_parent(node_id)
+    }
+
     /// Returns the `NodeId` of `id`'s nearest module parent, or `id` itself if no
     /// module parent is in this map.
     pub fn get_module_parent_node(&self, id: NodeId) -> NodeId {
@@ -770,6 +888,12 @@ impl<'hir> Map<'hir> {
         self.local_def_id(self.get_parent(id))
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_parent_did_by_hir_id(&self, id: HirId) -> DefId {
+        let node_id = self.hir_to_node_id(id);
+        self.get_parent_did(node_id)
+    }
+
     pub fn get_foreign_abi(&self, id: NodeId) -> Abi {
         let parent = self.get_parent(id);
         if let Some(entry) = self.find_entry(parent) {
@@ -783,6 +907,12 @@ impl<'hir> Map<'hir> {
         bug!("expected foreign mod or inlined parent, found {}", self.node_to_string(parent))
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn get_foreign_abi_by_hir_id(&self, id: HirId) -> Abi {
+        let node_id = self.hir_to_node_id(id);
+        self.get_foreign_abi(node_id)
+    }
+
     pub fn expect_item(&self, id: NodeId) -> &'hir Item {
         match self.find(id) { // read recorded by `find`
             Some(Node::Item(item)) => item,
@@ -790,6 +920,12 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn expect_item_by_hir_id(&self, id: HirId) -> &'hir Item {
+        let node_id = self.hir_to_node_id(id);
+        self.expect_item(node_id)
+    }
+
     pub fn expect_impl_item(&self, id: NodeId) -> &'hir ImplItem {
         match self.find(id) {
             Some(Node::ImplItem(item)) => item,
@@ -797,6 +933,18 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn expect_impl_item_by_hir_id(&self, id: HirId) -> &'hir ImplItem {
+        let node_id = self.hir_to_node_id(id);
+        self.expect_impl_item(node_id)
+    }
+
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn expect_trait_item_by_hir_id(&self, id: HirId) -> &'hir TraitItem {
+        let node_id = self.hir_to_node_id(id);
+        self.expect_trait_item(node_id)
+    }
+
     pub fn expect_trait_item(&self, id: NodeId) -> &'hir TraitItem {
         match self.find(id) {
             Some(Node::TraitItem(item)) => item,
@@ -804,7 +952,9 @@ impl<'hir> Map<'hir> {
         }
     }
 
-    pub fn expect_variant_data(&self, id: NodeId) -> &'hir VariantData {
+    pub fn expect_variant_data(&self, id: HirId) -> &'hir VariantData {
+        let id = self.hir_to_node_id(id); // FIXME(@ljedrz): remove when possible
+
         match self.find(id) {
             Some(Node::Item(i)) => {
                 match i.node {
@@ -819,7 +969,9 @@ impl<'hir> Map<'hir> {
         }
     }
 
-    pub fn expect_variant(&self, id: NodeId) -> &'hir Variant {
+    pub fn expect_variant(&self, id: HirId) -> &'hir Variant {
+        let id = self.hir_to_node_id(id); // FIXME(@ljedrz): remove when possible
+
         match self.find(id) {
             Some(Node::Variant(variant)) => variant,
             _ => bug!("expected variant, found {}", self.node_to_string(id)),
@@ -840,6 +992,12 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn expect_expr_by_hir_id(&self, id: HirId) -> &'hir Expr {
+        let node_id = self.hir_to_node_id(id);
+        self.expect_expr(node_id)
+    }
+
     /// Returns the name associated with the given NodeId's AST.
     pub fn name(&self, id: NodeId) -> Name {
         match self.get(id) {
@@ -851,12 +1009,18 @@ impl<'hir> Map<'hir> {
             Node::Field(f) => f.ident.name,
             Node::Lifetime(lt) => lt.name.ident().name,
             Node::GenericParam(param) => param.name.ident().name,
-            Node::Binding(&Pat { node: PatKind::Binding(_,_,l,_), .. }) => l.name,
+            Node::Binding(&Pat { node: PatKind::Binding(_, _, _, l, _), .. }) => l.name,
             Node::StructCtor(_) => self.name(self.get_parent(id)),
             _ => bug!("no name for {}", self.node_to_string(id))
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn name_by_hir_id(&self, id: HirId) -> Name {
+        let node_id = self.hir_to_node_id(id);
+        self.name(node_id)
+    }
+
     /// Given a node ID, get a list of attributes associated with the AST
     /// corresponding to the Node ID
     pub fn attrs(&self, id: NodeId) -> &'hir [ast::Attribute] {
@@ -879,6 +1043,12 @@ impl<'hir> Map<'hir> {
         attrs.unwrap_or(&[])
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn attrs_by_hir_id(&self, id: HirId) -> &'hir [ast::Attribute] {
+        let node_id = self.hir_to_node_id(id);
+        self.attrs(node_id)
+    }
+
     /// Returns an iterator that yields the node id's with paths that
     /// match `parts`.  (Requires `parts` is non-empty.)
     ///
@@ -928,6 +1098,12 @@ impl<'hir> Map<'hir> {
         }
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn span_by_hir_id(&self, id: HirId) -> Span {
+        let node_id = self.hir_to_node_id(id);
+        self.span(node_id)
+    }
+
     pub fn span_if_local(&self, id: DefId) -> Option<Span> {
         self.as_local_node_id(id).map(|id| self.span(id))
     }
@@ -936,13 +1112,28 @@ impl<'hir> Map<'hir> {
         node_id_to_string(self, id, true)
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn hir_to_string(&self, id: HirId) -> String {
+        hir_id_to_string(self, id, true)
+    }
+
     pub fn node_to_user_string(&self, id: NodeId) -> String {
         node_id_to_string(self, id, false)
     }
 
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn hir_to_user_string(&self, id: HirId) -> String {
+        hir_id_to_string(self, id, false)
+    }
+
     pub fn node_to_pretty_string(&self, id: NodeId) -> String {
         print::to_string(self, |s| s.print_node(self.get(id)))
     }
+
+    // FIXME(@ljedrz): replace the NodeId variant
+    pub fn hir_to_pretty_string(&self, id: HirId) -> String {
+        print::to_string(self, |s| s.print_node(self.get_by_hir_id(id)))
+    }
 }
 
 pub struct NodesMatchingSuffix<'a, 'hir:'a> {
@@ -953,7 +1144,7 @@ pub struct NodesMatchingSuffix<'a, 'hir:'a> {
 }
 
 impl<'a, 'hir> NodesMatchingSuffix<'a, 'hir> {
-    /// Returns true only if some suffix of the module path for parent
+    /// Returns `true` only if some suffix of the module path for parent
     /// matches `self.in_which`.
     ///
     /// In other words: let `[x_0,x_1,...,x_k]` be `self.in_which`;
@@ -1046,13 +1237,13 @@ impl Named for StructField { fn name(&self) -> Name { self.ident.name } }
 impl Named for TraitItem { fn name(&self) -> Name { self.ident.name } }
 impl Named for ImplItem { fn name(&self) -> Name { self.ident.name } }
 
-pub fn map_crate<'hir>(sess: &::session::Session,
+pub fn map_crate<'hir>(sess: &crate::session::Session,
                        cstore: &CrateStoreDyn,
                        forest: &'hir Forest,
                        definitions: &'hir Definitions)
                        -> Map<'hir> {
     let ((map, crate_hash), hir_to_node_id) = join(|| {
-        let hcx = ::ich::StableHashingContext::new(sess, &forest.krate, definitions, cstore);
+        let hcx = crate::ich::StableHashingContext::new(sess, &forest.krate, definitions, cstore);
 
         let mut collector = NodeCollector::root(sess,
                                                 &forest.krate,
@@ -1163,7 +1354,7 @@ fn node_id_to_string(map: &Map<'_>, id: NodeId, include_id: bool) -> String {
     let path_str = || {
         // This functionality is used for debugging, try to use TyCtxt to get
         // the user-friendly path, otherwise fall back to stringifying DefPath.
-        ::ty::tls::with_opt(|tcx| {
+        crate::ty::tls::with_opt(|tcx| {
             if let Some(tcx) = tcx {
                 tcx.node_path_str(id)
             } else if let Some(path) = map.def_path_from_id(id) {
@@ -1286,6 +1477,12 @@ fn node_id_to_string(map: &Map<'_>, id: NodeId, include_id: bool) -> String {
     }
 }
 
+// FIXME(@ljedrz): replace the NodeId variant
+fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
+    let node_id = map.hir_to_node_id(id);
+    node_id_to_string(map, node_id, include_id)
+}
+
 pub fn describe_def(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<Def> {
     if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
         tcx.hir().describe_def(node_id)
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index fc4bd05476f6c..d0b92587b59f0 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -10,26 +10,27 @@ pub use self::PrimTy::*;
 pub use self::UnOp::*;
 pub use self::UnsafeSource::*;
 
-use hir::def::Def;
-use hir::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX};
-use util::nodemap::{NodeMap, FxHashSet};
-use mir::mono::Linkage;
+use crate::hir::def::Def;
+use crate::hir::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX};
+use crate::util::nodemap::{NodeMap, FxHashSet};
+use crate::mir::mono::Linkage;
 
+use errors::FatalError;
 use syntax_pos::{Span, DUMMY_SP, symbol::InternedString};
-use syntax::source_map::{self, Spanned};
+use syntax::source_map::Spanned;
 use rustc_target::spec::abi::Abi;
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, DUMMY_NODE_ID, AsmDialect};
-use syntax::ast::{Attribute, Lit, StrStyle, FloatTy, IntTy, UintTy};
-use syntax::attr::InlineAttr;
+use syntax::ast::{Attribute, Label, Lit, StrStyle, FloatTy, IntTy, UintTy};
+use syntax::attr::{InlineAttr, OptimizeAttr};
 use syntax::ext::hygiene::SyntaxContext;
 use syntax::ptr::P;
 use syntax::symbol::{Symbol, keywords};
 use syntax::tokenstream::TokenStream;
 use syntax::util::parser::ExprPrecedence;
-use ty::AdtKind;
-use ty::query::Providers;
+use crate::ty::AdtKind;
+use crate::ty::query::Providers;
 
-use rustc_data_structures::sync::{ParallelIterator, par_iter, Send, Sync, scope};
+use rustc_data_structures::sync::{ParallelIterator, par_iter, Send, Sync};
 use rustc_data_structures::thin_vec::ThinVec;
 
 use serialize::{self, Encoder, Encodable, Decoder, Decodable};
@@ -61,17 +62,17 @@ pub mod map;
 pub mod pat_util;
 pub mod print;
 
-/// A HirId uniquely identifies a node in the HIR of the current crate. It is
-/// composed of the `owner`, which is the DefIndex of the directly enclosing
-/// hir::Item, hir::TraitItem, or hir::ImplItem (i.e., the closest "item-like"),
+/// Uniquely identifies a node in the HIR of the current crate. It is
+/// composed of the `owner`, which is the `DefIndex` of the directly enclosing
+/// `hir::Item`, `hir::TraitItem`, or `hir::ImplItem` (i.e., the closest "item-like"),
 /// and the `local_id` which is unique within the given owner.
 ///
 /// This two-level structure makes for more stable values: One can move an item
 /// around within the source code, or add or remove stuff before it, without
-/// the local_id part of the HirId changing, which is a very useful property in
+/// the `local_id` part of the `HirId` changing, which is a very useful property in
 /// incremental compilation where we have to persist things through changes to
 /// the code base.
-#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
 pub struct HirId {
     pub owner: DefIndex,
     pub local_id: ItemLocalId,
@@ -129,7 +130,7 @@ mod item_local_id_inner {
 
 pub use self::item_local_id_inner::ItemLocalId;
 
-/// The `HirId` corresponding to CRATE_NODE_ID and CRATE_DEF_INDEX
+/// The `HirId` corresponding to `CRATE_NODE_ID` and `CRATE_DEF_INDEX`.
 pub const CRATE_HIR_ID: HirId = HirId {
     owner: CRATE_DEF_INDEX,
     local_id: ItemLocalId::from_u32_const(0)
@@ -142,24 +143,14 @@ pub const DUMMY_HIR_ID: HirId = HirId {
 
 pub const DUMMY_ITEM_LOCAL_ID: ItemLocalId = ItemLocalId::MAX;
 
-#[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
-pub struct Label {
-    pub ident: Ident,
-}
-
-impl fmt::Debug for Label {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "label({:?})", self.ident)
-    }
-}
-
 #[derive(Clone, RustcEncodable, RustcDecodable, Copy)]
 pub struct Lifetime {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub span: Span,
 
-    /// Either "'a", referring to a named lifetime definition,
-    /// or "" (aka keywords::Invalid), for elision placeholders.
+    /// Either "`'a`", referring to a named lifetime definition,
+    /// or "``" (i.e., `keywords::Invalid`), for elision placeholders.
     ///
     /// HIR lowering inserts these placeholders in type paths that
     /// refer to type definitions needing lifetime parameters,
@@ -172,8 +163,9 @@ pub enum ParamName {
     /// Some user-given name like `T` or `'x`.
     Plain(Ident),
 
-    /// Synthetic name generated when user elided a lifetime in an impl header,
-    /// e.g., the lifetimes in cases like these:
+    /// Synthetic name generated when user elided a lifetime in an impl header.
+    ///
+    /// E.g., the lifetimes in cases like these:
     ///
     ///     impl Foo for &u32
     ///     impl Foo<'_> for u32
@@ -189,7 +181,7 @@ pub enum ParamName {
 
     /// Indicates an illegal name was given and an error has been
     /// repored (so we should squelch other derived errors). Occurs
-    /// when e.g., `'_` is used in the wrong place.
+    /// when, e.g., `'_` is used in the wrong place.
     Error,
 }
 
@@ -214,17 +206,17 @@ pub enum LifetimeName {
     /// User-given names or fresh (synthetic) names.
     Param(ParamName),
 
-    /// User typed nothing. e.g., the lifetime in `&u32`.
+    /// User wrote nothing (e.g., the lifetime in `&u32`).
     Implicit,
 
     /// Indicates an error during lowering (usually `'_` in wrong place)
     /// that was already reported.
     Error,
 
-    /// User typed `'_`.
+    /// User wrote specifies `'_`.
     Underscore,
 
-    /// User wrote `'static`
+    /// User wrote `'static`.
     Static,
 }
 
@@ -289,7 +281,7 @@ impl Lifetime {
     }
 }
 
-/// A "Path" is essentially Rust's notion of a name; for instance:
+/// A `Path` is essentially Rust's notion of a name; for instance,
 /// `std::cmp::PartialEq`. It's represented as a sequence of identifiers,
 /// along with a bunch of supporting information.
 #[derive(Clone, RustcEncodable, RustcDecodable)]
@@ -331,6 +323,7 @@ pub struct PathSegment {
     // affected. (In general, we don't bother to get the defs for synthesized
     // segments, only for segments which have come from the AST).
     pub id: Option<NodeId>,
+    pub hir_id: Option<HirId>,
     pub def: Option<Def>,
 
     /// Type/lifetime parameters attached to this path. They come in
@@ -348,11 +341,12 @@ pub struct PathSegment {
 }
 
 impl PathSegment {
-    /// Convert an identifier to the corresponding segment.
+    /// Converts an identifier to the corresponding segment.
     pub fn from_ident(ident: Ident) -> PathSegment {
         PathSegment {
             ident,
             id: None,
+            hir_id: None,
             def: None,
             infer_types: true,
             args: None,
@@ -362,6 +356,7 @@ impl PathSegment {
     pub fn new(
         ident: Ident,
         id: Option<NodeId>,
+        hir_id: Option<HirId>,
         def: Option<Def>,
         args: GenericArgs,
         infer_types: bool,
@@ -369,6 +364,7 @@ impl PathSegment {
         PathSegment {
             ident,
             id,
+            hir_id,
             def,
             infer_types,
             args: if args.is_empty() {
@@ -393,10 +389,17 @@ impl PathSegment {
     }
 }
 
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
+pub struct ConstArg {
+    pub value: AnonConst,
+    pub span: Span,
+}
+
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericArg {
     Lifetime(Lifetime),
     Type(Ty),
+    Const(ConstArg),
 }
 
 impl GenericArg {
@@ -404,6 +407,7 @@ impl GenericArg {
         match self {
             GenericArg::Lifetime(l) => l.span,
             GenericArg::Type(t) => t.span,
+            GenericArg::Const(c) => c.span,
         }
     }
 
@@ -411,6 +415,7 @@ impl GenericArg {
         match self {
             GenericArg::Lifetime(l) => l.id,
             GenericArg::Type(t) => t.id,
+            GenericArg::Const(c) => c.value.id,
         }
     }
 }
@@ -452,6 +457,7 @@ impl GenericArgs {
                         }
                         break;
                     }
+                    GenericArg::Const(_) => {}
                 }
             }
         }
@@ -468,6 +474,7 @@ impl GenericArgs {
             match arg {
                 GenericArg::Lifetime(_) => own_counts.lifetimes += 1,
                 GenericArg::Type(_) => own_counts.types += 1,
+                GenericArg::Const(_) => own_counts.consts += 1,
             };
         }
 
@@ -532,12 +539,16 @@ pub enum GenericParamKind {
     Type {
         default: Option<P<Ty>>,
         synthetic: Option<SyntheticTyParamKind>,
+    },
+    Const {
+        ty: P<Ty>,
     }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct GenericParam {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub name: ParamName,
     pub attrs: HirVec<Attribute>,
     pub bounds: GenericBounds,
@@ -551,6 +562,7 @@ pub struct GenericParam {
 pub struct GenericParamCount {
     pub lifetimes: usize,
     pub types: usize,
+    pub consts: usize,
 }
 
 /// Represents lifetimes and type parameters attached to a declaration
@@ -568,6 +580,7 @@ impl Generics {
             params: HirVec::new(),
             where_clause: WhereClause {
                 id: DUMMY_NODE_ID,
+                hir_id: DUMMY_HIR_ID,
                 predicates: HirVec::new(),
             },
             span: DUMMY_SP,
@@ -584,6 +597,7 @@ impl Generics {
             match param.kind {
                 GenericParamKind::Lifetime { .. } => own_counts.lifetimes += 1,
                 GenericParamKind::Type { .. } => own_counts.types += 1,
+                GenericParamKind::Const { .. } => own_counts.consts += 1,
             };
         }
 
@@ -600,17 +614,18 @@ impl Generics {
     }
 }
 
-/// Synthetic Type Parameters are converted to an other form during lowering, this allows
-/// to track the original form they had. Useful for error messages.
+/// Synthetic type parameters are converted to another form during lowering; this allows
+/// us to track the original form they had, and is useful for error messages.
 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum SyntheticTyParamKind {
     ImplTrait
 }
 
-/// A `where` clause in a definition
+/// A where-clause in a definition.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereClause {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub predicates: HirVec<WherePredicate>,
 }
 
@@ -626,7 +641,7 @@ impl WhereClause {
     }
 }
 
-/// A single predicate in a `where` clause
+/// A single predicate in a where-clause.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum WherePredicate {
     /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
@@ -647,19 +662,19 @@ impl WherePredicate {
     }
 }
 
-/// A type bound, eg `for<'c> Foo: Send+Clone+'c`
+/// A type bound (e.g., `for<'c> Foo: Send + Clone + 'c`).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereBoundPredicate {
     pub span: Span,
-    /// Any generics from a `for` binding
+    /// Any generics from a `for` binding.
     pub bound_generic_params: HirVec<GenericParam>,
-    /// The type being bounded
+    /// The type being bounded.
     pub bounded_ty: P<Ty>,
-    /// Trait and lifetime bounds (`Clone+Send+'static`)
+    /// Trait and lifetime bounds (e.g., `Clone + Send + 'static`).
     pub bounds: GenericBounds,
 }
 
-/// A lifetime predicate, e.g., `'a: 'b+'c`
+/// A lifetime predicate (e.g., `'a: 'b + 'c`).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereRegionPredicate {
     pub span: Span,
@@ -667,10 +682,11 @@ pub struct WhereRegionPredicate {
     pub bounds: GenericBounds,
 }
 
-/// An equality predicate (unsupported), e.g., `T=int`
+/// An equality predicate (e.g., `T = int`); currently unsupported.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereEqPredicate {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub span: Span,
     pub lhs_ty: P<Ty>,
     pub rhs_ty: P<Ty>,
@@ -760,27 +776,21 @@ impl Crate {
         }
     }
 
-    /// A parallel version of visit_all_item_likes
+    /// A parallel version of `visit_all_item_likes`.
     pub fn par_visit_all_item_likes<'hir, V>(&'hir self, visitor: &V)
         where V: itemlikevisit::ParItemLikeVisitor<'hir> + Sync + Send
     {
-        scope(|s| {
-            s.spawn(|_| {
-                par_iter(&self.items).for_each(|(_, item)| {
-                    visitor.visit_item(item);
-                });
+        parallel!({
+            par_iter(&self.items).for_each(|(_, item)| {
+                visitor.visit_item(item);
             });
-
-            s.spawn(|_| {
-                par_iter(&self.trait_items).for_each(|(_, trait_item)| {
-                    visitor.visit_trait_item(trait_item);
-                });
+        }, {
+            par_iter(&self.trait_items).for_each(|(_, trait_item)| {
+                visitor.visit_trait_item(trait_item);
             });
-
-            s.spawn(|_| {
-                par_iter(&self.impl_items).for_each(|(_, impl_item)| {
-                    visitor.visit_impl_item(impl_item);
-                });
+        }, {
+            par_iter(&self.impl_items).for_each(|(_, impl_item)| {
+                visitor.visit_impl_item(impl_item);
             });
         });
     }
@@ -799,6 +809,7 @@ pub struct MacroDef {
     pub vis: Visibility,
     pub attrs: HirVec<Attribute>,
     pub id: NodeId,
+    pub hir_id: HirId,
     pub span: Span,
     pub body: TokenStream,
     pub legacy: bool,
@@ -806,14 +817,14 @@ pub struct MacroDef {
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Block {
-    /// Statements in a block
+    /// Statements in a block.
     pub stmts: HirVec<Stmt>,
     /// An expression at the end of the block
-    /// without a semicolon, if any
+    /// without a semicolon, if any.
     pub expr: Option<P<Expr>>,
     pub id: NodeId,
     pub hir_id: HirId,
-    /// Distinguishes between `unsafe { ... }` and `{ ... }`
+    /// Distinguishes between `unsafe { ... }` and `{ ... }`.
     pub rules: BlockCheckMode,
     pub span: Span,
     /// If true, then there may exist `break 'a` values that aim to
@@ -880,17 +891,18 @@ impl Pat {
     }
 }
 
-/// A single field in a struct pattern
+/// A single field in a struct pattern.
 ///
 /// Patterns like the fields of Foo `{ x, ref y, ref mut z }`
 /// are treated the same as` x: x, y: ref y, z: ref mut z`,
-/// except is_shorthand is true
+/// except `is_shorthand` is true.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct FieldPat {
     pub id: NodeId,
-    /// The identifier for the field
+    pub hir_id: HirId,
+    /// The identifier for the field.
     pub ident: Ident,
-    /// The pattern the field is destructured to
+    /// The pattern the field is destructured to.
     pub pat: P<Pat>,
     pub is_shorthand: bool,
 }
@@ -927,41 +939,46 @@ pub enum RangeEnd {
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum PatKind {
-    /// Represents a wildcard pattern (`_`)
+    /// Represents a wildcard pattern (i.e., `_`).
     Wild,
 
     /// A fresh binding `ref mut binding @ OPT_SUBPATTERN`.
     /// The `NodeId` is the canonical ID for the variable being bound,
-    /// e.g., in `Ok(x) | Err(x)`, both `x` use the same canonical ID,
+    /// (e.g., in `Ok(x) | Err(x)`, both `x` use the same canonical ID),
     /// which is the pattern ID of the first `x`.
-    Binding(BindingAnnotation, NodeId, Ident, Option<P<Pat>>),
+    Binding(BindingAnnotation, NodeId, HirId, Ident, Option<P<Pat>>),
 
-    /// A struct or struct variant pattern, e.g., `Variant {x, y, ..}`.
+    /// A struct or struct variant pattern (e.g., `Variant {x, y, ..}`).
     /// The `bool` is `true` in the presence of a `..`.
     Struct(QPath, HirVec<Spanned<FieldPat>>, bool),
 
     /// A tuple struct/variant pattern `Variant(x, y, .., z)`.
     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
-    /// 0 <= position <= subpats.len()
+    /// `0 <= position <= subpats.len()`
     TupleStruct(QPath, HirVec<P<Pat>>, Option<usize>),
 
     /// A path pattern for an unit struct/variant or a (maybe-associated) constant.
     Path(QPath),
 
-    /// A tuple pattern `(a, b)`.
+    /// A tuple pattern (e.g., `(a, b)`).
     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
-    /// 0 <= position <= subpats.len()
+    /// `0 <= position <= subpats.len()`
     Tuple(HirVec<P<Pat>>, Option<usize>),
-    /// A `box` pattern
+
+    /// A `box` pattern.
     Box(P<Pat>),
-    /// A reference pattern, e.g., `&mut (a, b)`
+
+    /// A reference pattern (e.g., `&mut (a, b)`).
     Ref(P<Pat>, Mutability),
-    /// A literal
+
+    /// A literal.
     Lit(P<Expr>),
-    /// A range pattern, e.g., `1...2` or `1..2`
+
+    /// A range pattern (e.g., `1...2` or `1..2`).
     Range(P<Expr>, P<Expr>, RangeEnd),
+
     /// `[a, b, ..i, y, z]` is represented as:
-    ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`
+    ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`.
     Slice(HirVec<P<Pat>>, Option<P<Pat>>, HirVec<P<Pat>>),
 }
 
@@ -972,7 +989,7 @@ pub enum Mutability {
 }
 
 impl Mutability {
-    /// Return MutMutable only if both arguments are mutable.
+    /// Returns `MutMutable` only if both arguments are mutable.
     pub fn and(self, other: Self) -> Self {
         match self {
             MutMutable => other,
@@ -983,41 +1000,41 @@ impl Mutability {
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, Hash)]
 pub enum BinOpKind {
-    /// The `+` operator (addition)
+    /// The `+` operator (addition).
     Add,
-    /// The `-` operator (subtraction)
+    /// The `-` operator (subtraction).
     Sub,
-    /// The `*` operator (multiplication)
+    /// The `*` operator (multiplication).
     Mul,
-    /// The `/` operator (division)
+    /// The `/` operator (division).
     Div,
-    /// The `%` operator (modulus)
+    /// The `%` operator (modulus).
     Rem,
-    /// The `&&` operator (logical and)
+    /// The `&&` operator (logical and).
     And,
-    /// The `||` operator (logical or)
+    /// The `||` operator (logical or).
     Or,
-    /// The `^` operator (bitwise xor)
+    /// The `^` operator (bitwise xor).
     BitXor,
-    /// The `&` operator (bitwise and)
+    /// The `&` operator (bitwise and).
     BitAnd,
-    /// The `|` operator (bitwise or)
+    /// The `|` operator (bitwise or).
     BitOr,
-    /// The `<<` operator (shift left)
+    /// The `<<` operator (shift left).
     Shl,
-    /// The `>>` operator (shift right)
+    /// The `>>` operator (shift right).
     Shr,
-    /// The `==` operator (equality)
+    /// The `==` operator (equality).
     Eq,
-    /// The `<` operator (less than)
+    /// The `<` operator (less than).
     Lt,
-    /// The `<=` operator (less than or equal to)
+    /// The `<=` operator (less than or equal to).
     Le,
-    /// The `!=` operator (not equal to)
+    /// The `!=` operator (not equal to).
     Ne,
-    /// The `>=` operator (greater than or equal to)
+    /// The `>=` operator (greater than or equal to).
     Ge,
-    /// The `>` operator (greater than)
+    /// The `>` operator (greater than).
     Gt,
 }
 
@@ -1082,7 +1099,7 @@ impl BinOpKind {
         }
     }
 
-    /// Returns `true` if the binary operator takes its arguments by value
+    /// Returns `true` if the binary operator takes its arguments by value.
     pub fn is_by_value(self) -> bool {
         !self.is_comparison()
     }
@@ -1117,11 +1134,11 @@ pub type BinOp = Spanned<BinOpKind>;
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy, Hash)]
 pub enum UnOp {
-    /// The `*` operator for dereferencing
+    /// The `*` operator (deferencing).
     UnDeref,
-    /// The `!` operator for logical inversion
+    /// The `!` operator (logical negation).
     UnNot,
-    /// The `-` operator for negation
+    /// The `-` operator (negation).
     UnNeg,
 }
 
@@ -1134,7 +1151,7 @@ impl UnOp {
         }
     }
 
-    /// Returns `true` if the unary operator takes its argument by value
+    /// Returns `true` if the unary operator takes its argument by value.
     pub fn is_by_value(self) -> bool {
         match self {
             UnNeg | UnNot => true,
@@ -1143,56 +1160,54 @@ impl UnOp {
     }
 }
 
-/// A statement
-pub type Stmt = Spanned<StmtKind>;
+/// A statement.
+#[derive(Clone, RustcEncodable, RustcDecodable)]
+pub struct Stmt {
+    pub id: NodeId,
+    pub hir_id: HirId,
+    pub node: StmtKind,
+    pub span: Span,
+}
 
-impl fmt::Debug for StmtKind {
+impl fmt::Debug for Stmt {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        // Sadness.
-        let spanned = source_map::dummy_spanned(self.clone());
-        write!(f,
-               "stmt({}: {})",
-               spanned.node.id(),
-               print::to_string(print::NO_ANN, |s| s.print_stmt(&spanned)))
+        write!(f, "stmt({}: {})", self.id,
+               print::to_string(print::NO_ANN, |s| s.print_stmt(self)))
     }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable)]
 pub enum StmtKind {
-    /// Could be an item or a local (let) binding:
-    Decl(P<Decl>, NodeId),
+    /// A local (`let`) binding.
+    Local(P<Local>),
+
+    /// An item binding.
+    Item(ItemId),
 
-    /// Expr without trailing semi-colon (must have unit type):
-    Expr(P<Expr>, NodeId),
+    /// An expression without a trailing semi-colon (must have unit type).
+    Expr(P<Expr>),
 
-    /// Expr with trailing semi-colon (may have any type):
-    Semi(P<Expr>, NodeId),
+    /// An expression with a trailing semi-colon (may have any type).
+    Semi(P<Expr>),
 }
 
 impl StmtKind {
     pub fn attrs(&self) -> &[Attribute] {
         match *self {
-            StmtKind::Decl(ref d, _) => d.node.attrs(),
-            StmtKind::Expr(ref e, _) |
-            StmtKind::Semi(ref e, _) => &e.attrs,
-        }
-    }
-
-    pub fn id(&self) -> NodeId {
-        match *self {
-            StmtKind::Decl(_, id) |
-            StmtKind::Expr(_, id) |
-            StmtKind::Semi(_, id) => id,
+            StmtKind::Local(ref l) => &l.attrs,
+            StmtKind::Item(_) => &[],
+            StmtKind::Expr(ref e) |
+            StmtKind::Semi(ref e) => &e.attrs,
         }
     }
 }
 
-/// Local represents a `let` statement, e.g., `let <pat>:<ty> = <expr>;`
+/// Represents a `let` statement (i.e., `let <pat>:<ty> = <expr>;`).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Local {
     pub pat: P<Pat>,
     pub ty: Option<P<Ty>>,
-    /// Initializer expression to set the value, if any
+    /// Initializer expression to set the value, if any.
     pub init: Option<P<Expr>>,
     pub id: NodeId,
     pub hir_id: HirId,
@@ -1201,33 +1216,7 @@ pub struct Local {
     pub source: LocalSource,
 }
 
-pub type Decl = Spanned<DeclKind>;
-
-#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub enum DeclKind {
-    /// A local (let) binding:
-    Local(P<Local>),
-    /// An item binding:
-    Item(ItemId),
-}
-
-impl DeclKind {
-    pub fn attrs(&self) -> &[Attribute] {
-        match *self {
-            DeclKind::Local(ref l) => &l.attrs,
-            DeclKind::Item(_) => &[]
-        }
-    }
-
-    pub fn is_local(&self) -> bool {
-        match *self {
-            DeclKind::Local(_) => true,
-            _ => false,
-        }
-    }
-}
-
-/// represents one arm of a 'match'
+/// Represents a single arm of a `match` expression.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Arm {
     pub attrs: HirVec<Attribute>,
@@ -1244,6 +1233,7 @@ pub enum Guard {
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Field {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub ident: Ident,
     pub expr: P<Expr>,
     pub span: Span,
@@ -1266,7 +1256,7 @@ pub enum UnsafeSource {
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct BodyId {
-    pub node_id: NodeId,
+    pub hir_id: HirId,
 }
 
 /// The body of a function, closure, or constant value. In the case of
@@ -1300,7 +1290,7 @@ pub struct Body {
 impl Body {
     pub fn id(&self) -> BodyId {
         BodyId {
-            node_id: self.value.id
+            hir_id: self.value.hir_id,
         }
     }
 }
@@ -1310,6 +1300,9 @@ pub enum BodyOwnerKind {
     /// Functions and methods.
     Fn,
 
+    /// Closures
+    Closure,
+
     /// Constants and associated constants.
     Const,
 
@@ -1317,12 +1310,21 @@ pub enum BodyOwnerKind {
     Static(Mutability),
 }
 
+impl BodyOwnerKind {
+    pub fn is_fn_or_closure(self) -> bool {
+        match self {
+            BodyOwnerKind::Fn | BodyOwnerKind::Closure => true,
+            BodyOwnerKind::Const | BodyOwnerKind::Static(_) => false,
+        }
+    }
+}
+
 /// A constant (expression) that's not an item or associated item,
 /// but needs its own `DefId` for type-checking, const-eval, etc.
 /// These are usually found nested inside types (e.g., array lengths)
 /// or expressions (e.g., repeat counts), and also used to define
 /// explicit discriminant values for enum variants.
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
 pub struct AnonConst {
     pub id: NodeId,
     pub hir_id: HirId,
@@ -1339,6 +1341,10 @@ pub struct Expr {
     pub hir_id: HirId,
 }
 
+// `Expr` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(target_arch = "x86_64")]
+static_assert!(MEM_SIZE_OF_EXPR: std::mem::size_of::<Expr>() == 72);
+
 impl Expr {
     pub fn precedence(&self) -> ExprPrecedence {
         match self.node {
@@ -1440,16 +1446,16 @@ impl fmt::Debug for Expr {
 pub enum ExprKind {
     /// A `box x` expression.
     Box(P<Expr>),
-    /// An array (`[a, b, c, d]`)
+    /// An array (e.g., `[a, b, c, d]`).
     Array(HirVec<Expr>),
-    /// A function call
+    /// A function call.
     ///
     /// The first field resolves to the function itself (usually an `ExprKind::Path`),
     /// and the second field is the list of arguments.
     /// This also represents calling the constructor of
     /// tuple-like ADTs such as tuple structs and enum variants.
     Call(P<Expr>, HirVec<Expr>),
-    /// A method call (`x.foo::<'static, Bar, Baz>(a, b, c, d)`)
+    /// A method call (e.g., `x.foo::<'static, Bar, Baz>(a, b, c, d)`).
     ///
     /// The `PathSegment`/`Span` represent the method name and its generic arguments
     /// (within the angle brackets).
@@ -1458,64 +1464,65 @@ pub enum ExprKind {
     /// and the remaining elements are the rest of the arguments.
     /// Thus, `x.foo::<Bar, Baz>(a, b, c, d)` is represented as
     /// `ExprKind::MethodCall(PathSegment { foo, [Bar, Baz] }, [x, a, b, c, d])`.
-    MethodCall(PathSegment, Span, HirVec<Expr>),
-    /// A tuple (`(a, b, c ,d)`)
+    MethodCall(P<PathSegment>, Span, HirVec<Expr>),
+    /// A tuple (e.g., `(a, b, c ,d)`).
     Tup(HirVec<Expr>),
-    /// A binary operation (For example: `a + b`, `a * b`)
+    /// A binary operation (e.g., `a + b`, `a * b`).
     Binary(BinOp, P<Expr>, P<Expr>),
-    /// A unary operation (For example: `!x`, `*x`)
+    /// A unary operation (e.g., `!x`, `*x`).
     Unary(UnOp, P<Expr>),
-    /// A literal (For example: `1`, `"foo"`)
-    Lit(P<Lit>),
-    /// A cast (`foo as f64`)
+    /// A literal (e.g., `1`, `"foo"`).
+    Lit(Lit),
+    /// A cast (e.g., `foo as f64`).
     Cast(P<Expr>, P<Ty>),
+    /// A type reference (e.g., `Foo`).
     Type(P<Expr>, P<Ty>),
-    /// An `if` block, with an optional else block
+    /// An `if` block, with an optional else block.
     ///
-    /// `if expr { expr } else { expr }`
+    /// I.e., `if <expr> { <expr> } else { <expr> }`.
     If(P<Expr>, P<Expr>, Option<P<Expr>>),
     /// A while loop, with an optional label
     ///
-    /// `'label: while expr { block }`
+    /// I.e., `'label: while expr { <block> }`.
     While(P<Expr>, P<Block>, Option<Label>),
-    /// Conditionless loop (can be exited with break, continue, or return)
+    /// A conditionless loop (can be exited with `break`, `continue`, or `return`).
     ///
-    /// `'label: loop { block }`
+    /// I.e., `'label: loop { <block> }`.
     Loop(P<Block>, Option<Label>, LoopSource),
     /// A `match` block, with a source that indicates whether or not it is
     /// the result of a desugaring, and if so, which kind.
     Match(P<Expr>, HirVec<Arm>, MatchSource),
-    /// A closure (for example, `move |a, b, c| {a + b + c}`).
+    /// A closure (e.g., `move |a, b, c| {a + b + c}`).
     ///
-    /// The final span is the span of the argument block `|...|`
+    /// The final span is the span of the argument block `|...|`.
     ///
     /// This may also be a generator literal, indicated by the final boolean,
-    /// in that case there is an GeneratorClause.
+    /// in that case there is an `GeneratorClause`.
     Closure(CaptureClause, P<FnDecl>, BodyId, Span, Option<GeneratorMovability>),
-    /// A block (`'label: { ... }`)
+    /// A block (e.g., `'label: { ... }`).
     Block(P<Block>, Option<Label>),
 
-    /// An assignment (`a = foo()`)
+    /// An assignment (e.g., `a = foo()`).
     Assign(P<Expr>, P<Expr>),
-    /// An assignment with an operator
+    /// An assignment with an operator.
     ///
-    /// For example, `a += 1`.
+    /// E.g., `a += 1`.
     AssignOp(BinOp, P<Expr>, P<Expr>),
-    /// Access of a named (`obj.foo`) or unnamed (`obj.0`) struct or tuple field
+    /// Access of a named (e.g., `obj.foo`) or unnamed (e.g., `obj.0`) struct or tuple field.
     Field(P<Expr>, Ident),
-    /// An indexing operation (`foo[2]`)
+    /// An indexing operation (`foo[2]`).
     Index(P<Expr>, P<Expr>),
 
     /// Path to a definition, possibly containing lifetime or type parameters.
     Path(QPath),
 
-    /// A referencing operation (`&a` or `&mut a`)
+    /// A referencing operation (i.e., `&a` or `&mut a`).
     AddrOf(Mutability, P<Expr>),
-    /// A `break`, with an optional label to break
+    /// A `break`, with an optional label to break.
     Break(Destination, Option<P<Expr>>),
-    /// A `continue`, with an optional label
+    /// A `continue`, with an optional label.
     Continue(Destination),
-    /// A `return`, with an optional value to be returned
+    /// A `return`, with an optional value to be returned.
     Ret(Option<P<Expr>>),
 
     /// Inline assembly (from `asm!`), with its outputs and inputs.
@@ -1525,7 +1532,7 @@ pub enum ExprKind {
     ///
     /// For example, `Foo {x: 1, y: 2}`, or
     /// `Foo {x: 1, .. base}`, where `base` is the `Option<Expr>`.
-    Struct(QPath, HirVec<Field>, Option<P<Expr>>),
+    Struct(P<QPath>, HirVec<Field>, Option<P<Expr>>),
 
     /// An array literal constructed from one repeated element.
     ///
@@ -1533,10 +1540,10 @@ pub enum ExprKind {
     /// to be repeated; the second is the number of times to repeat it.
     Repeat(P<Expr>, AnonConst),
 
-    /// A suspension point for generators. This is `yield <expr>` in Rust.
+    /// A suspension point for generators (i.e., `yield <expr>`).
     Yield(P<Expr>),
 
-    /// Placeholder for an expression that wasn't syntactically well formed in some way.
+    /// A placeholder for an expression that wasn't syntactically well formed in some way.
     Err,
 }
 
@@ -1546,12 +1553,12 @@ pub enum QPath {
     /// Path to a definition, optionally "fully-qualified" with a `Self`
     /// type, if the path points to an associated item in a trait.
     ///
-    /// e.g., an unqualified path like `Clone::clone` has `None` for `Self`,
+    /// E.g., an unqualified path like `Clone::clone` has `None` for `Self`,
     /// while `<Vec<T> as Clone>::clone` has `Some(Vec<T>)` for `Self`,
     /// even though they both have the same two-segment `Clone::clone` `Path`.
     Resolved(Option<P<Ty>>, P<Path>),
 
-    /// Type-related paths, e.g., `<T>::default` or `<T>::Output`.
+    /// Type-related paths (e.g., `<T>::default` or `<T>::Output`).
     /// Will be resolved by type-checking to an associated item.
     ///
     /// UFCS source paths can desugar into this, with `Vec::new` turning into
@@ -1560,41 +1567,41 @@ pub enum QPath {
     TypeRelative(P<Ty>, P<PathSegment>)
 }
 
-/// Hints at the original code for a let statement
+/// Hints at the original code for a let statement.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum LocalSource {
-    /// A `match _ { .. }`
+    /// A `match _ { .. }`.
     Normal,
-    /// A desugared `for _ in _ { .. }` loop
+    /// A desugared `for _ in _ { .. }` loop.
     ForLoopDesugar,
 }
 
-/// Hints at the original code for a `match _ { .. }`
+/// Hints at the original code for a `match _ { .. }`.
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum MatchSource {
-    /// A `match _ { .. }`
+    /// A `match _ { .. }`.
     Normal,
-    /// An `if let _ = _ { .. }` (optionally with `else { .. }`)
+    /// An `if let _ = _ { .. }` (optionally with `else { .. }`).
     IfLetDesugar {
         contains_else_clause: bool,
     },
     /// A `while let _ = _ { .. }` (which was desugared to a
-    /// `loop { match _ { .. } }`)
+    /// `loop { match _ { .. } }`).
     WhileLetDesugar,
-    /// A desugared `for _ in _ { .. }` loop
+    /// A desugared `for _ in _ { .. }` loop.
     ForLoopDesugar,
-    /// A desugared `?` operator
+    /// A desugared `?` operator.
     TryDesugar,
 }
 
-/// The loop type that yielded an ExprKind::Loop
+/// The loop type that yielded an `ExprKind::Loop`.
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
 pub enum LoopSource {
-    /// A `loop { .. }` loop
+    /// A `loop { .. }` loop.
     Loop,
-    /// A `while let _ = _ { .. }` loop
+    /// A `while let _ = _ { .. }` loop.
     WhileLet,
-    /// A `for _ in _ { .. }` loop
+    /// A `for _ in _ { .. }` loop.
     ForLoop,
 }
 
@@ -1739,6 +1746,7 @@ pub enum ImplItemKind {
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TypeBinding {
     pub id: NodeId,
+    pub hir_id: HirId,
     pub ident: Ident,
     pub ty: P<Ty>,
     pub span: Span,
@@ -1759,7 +1767,7 @@ impl fmt::Debug for Ty {
     }
 }
 
-/// Not represented directly in the AST, referred to by name through a ty_path.
+/// Not represented directly in the AST; referred to by name through a `ty_path`.
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum PrimTy {
     Int(IntTy),
@@ -1786,38 +1794,38 @@ pub struct ExistTy {
     pub impl_trait_fn: Option<DefId>,
 }
 
+/// The various kinds of types recognized by the compiler.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-/// The different kinds of types recognized by the compiler
 pub enum TyKind {
-    /// A variable length slice (`[T]`)
+    /// A variable length slice (i.e., `[T]`).
     Slice(P<Ty>),
-    /// A fixed length array (`[T; n]`)
+    /// A fixed length array (i.e., `[T; n]`).
     Array(P<Ty>, AnonConst),
-    /// A raw pointer (`*const T` or `*mut T`)
+    /// A raw pointer (i.e., `*const T` or `*mut T`).
     Ptr(MutTy),
-    /// A reference (`&'a T` or `&'a mut T`)
+    /// A reference (i.e., `&'a T` or `&'a mut T`).
     Rptr(Lifetime, MutTy),
-    /// A bare function (e.g., `fn(usize) -> bool`)
+    /// A bare function (e.g., `fn(usize) -> bool`).
     BareFn(P<BareFnTy>),
-    /// The never type (`!`)
+    /// The never type (`!`).
     Never,
-    /// A tuple (`(A, B, C, D,...)`)
+    /// A tuple (`(A, B, C, D,...)`).
     Tup(HirVec<Ty>),
     /// A path to a type definition (`module::module::...::Type`), or an
-    /// associated type, e.g., `<Vec<T> as Trait>::Type` or `<T>::Target`.
+    /// associated type (e.g., `<Vec<T> as Trait>::Type` or `<T>::Target`).
     ///
     /// Type parameters may be stored in each `PathSegment`.
     Path(QPath),
     /// A type definition itself. This is currently only used for the `existential type`
     /// item that `impl Trait` in return position desugars to.
     ///
-    /// The generic arg list are the lifetimes (and in the future possibly parameters) that are
-    /// actually bound on the `impl Trait`.
+    /// The generic argument list contains the lifetimes (and in the future possibly parameters)
+    /// that are actually bound on the `impl Trait`.
     Def(ItemId, HirVec<GenericArg>),
     /// A trait object type `Bound1 + Bound2 + Bound3`
     /// where `Bound` is a trait or a lifetime.
     TraitObject(HirVec<PolyTraitRef>, Lifetime),
-    /// Unused for now
+    /// Unused for now.
     Typeof(AnonConst),
     /// `TyKind::Infer` means the type should be inferred instead of it having been
     /// specified. This can appear anywhere in a type.
@@ -1847,7 +1855,7 @@ pub struct InlineAsm {
     pub ctxt: SyntaxContext,
 }
 
-/// represents an argument in a function header
+/// Represents an argument in a function header.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct Arg {
     pub pat: P<Pat>,
@@ -1855,7 +1863,7 @@ pub struct Arg {
     pub hir_id: HirId,
 }
 
-/// Represents the header (not the body) of a function declaration
+/// Represents the header (not the body) of a function declaration.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct FnDecl {
     pub inputs: HirVec<Ty>,
@@ -1978,7 +1986,7 @@ pub enum FunctionRetTy {
     /// closures default to inference. Span points to where return
     /// type would be inserted.
     DefaultReturn(Span),
-    /// Everything else
+    /// Everything else.
     Return(P<Ty>),
 }
 
@@ -2031,7 +2039,7 @@ pub struct VariantKind {
     pub ident: Ident,
     pub attrs: HirVec<Attribute>,
     pub data: VariantData,
-    /// Explicit discriminant, e.g., `Foo = 1`
+    /// Explicit discriminant (e.g., `Foo = 1`).
     pub disr_expr: Option<AnonConst>,
 }
 
@@ -2066,12 +2074,26 @@ pub struct TraitRef {
     pub hir_ref_id: HirId,
 }
 
+impl TraitRef {
+    /// Gets the `DefId` of the referenced trait. It _must_ actually be a trait or trait alias.
+    pub fn trait_def_id(&self) -> DefId {
+        match self.path.def {
+            Def::Trait(did) => did,
+            Def::TraitAlias(did) => did,
+            Def::Err => {
+                FatalError.raise();
+            }
+            _ => unreachable!(),
+        }
+    }
+}
+
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct PolyTraitRef {
-    /// The `'a` in `<'a> Foo<&'a T>`
+    /// The `'a` in `<'a> Foo<&'a T>`.
     pub bound_generic_params: HirVec<GenericParam>,
 
-    /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`
+    /// The `Foo<&'a T>` in `<'a> Foo<&'a T>`.
     pub trait_ref: TraitRef,
 
     pub span: Span,
@@ -2120,6 +2142,7 @@ pub struct StructField {
     pub ident: Ident,
     pub vis: Visibility,
     pub id: NodeId,
+    pub hir_id: HirId,
     pub ty: P<Ty>,
     pub attrs: HirVec<Attribute>,
 }
@@ -2145,21 +2168,30 @@ impl StructField {
 /// Id of the whole struct lives in `Item`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum VariantData {
-    Struct(HirVec<StructField>, NodeId),
-    Tuple(HirVec<StructField>, NodeId),
-    Unit(NodeId),
+    Struct(HirVec<StructField>, NodeId, HirId),
+    Tuple(HirVec<StructField>, NodeId, HirId),
+    Unit(NodeId, HirId),
 }
 
 impl VariantData {
     pub fn fields(&self) -> &[StructField] {
         match *self {
-            VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => fields,
+            VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, ..) => fields,
             _ => &[],
         }
     }
     pub fn id(&self) -> NodeId {
         match *self {
-            VariantData::Struct(_, id) | VariantData::Tuple(_, id) | VariantData::Unit(id) => id,
+            VariantData::Struct(_, id, ..)
+            | VariantData::Tuple(_, id, ..)
+            | VariantData::Unit(id, ..) => id,
+        }
+    }
+    pub fn hir_id(&self) -> HirId {
+        match *self {
+            VariantData::Struct(_, _, hir_id)
+            | VariantData::Tuple(_, _, hir_id)
+            | VariantData::Unit(_, hir_id) => hir_id,
         }
     }
     pub fn is_struct(&self) -> bool {
@@ -2219,7 +2251,7 @@ pub struct FnHeader {
 pub enum ItemKind {
     /// An `extern crate` item, with optional *original* crate name if the crate was renamed.
     ///
-    /// e.g., `extern crate foo` or `extern crate foo_bar as foo`
+    /// E.g., `extern crate foo` or `extern crate foo_bar as foo`.
     ExternCrate(Option<Name>),
 
     /// `use foo::bar::*;` or `use foo::bar::baz as quux;`
@@ -2284,7 +2316,7 @@ impl ItemKind {
             ItemKind::Union(..) => "union",
             ItemKind::Trait(..) => "trait",
             ItemKind::TraitAlias(..) => "trait alias",
-            ItemKind::Impl(..) => "item",
+            ItemKind::Impl(..) => "impl",
         }
     }
 
@@ -2316,7 +2348,7 @@ impl ItemKind {
 /// contains the item's id, naturally, but also the item's name and
 /// some other high-level details (like whether it is an associated
 /// type or method, and whether it is public). This allows other
-/// passes to find the impl they want without loading the id (which
+/// passes to find the impl they want without loading the ID (which
 /// means fewer edges in the incremental compilation graph).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TraitItemRef {
@@ -2328,10 +2360,10 @@ pub struct TraitItemRef {
 }
 
 /// A reference from an impl to one of its associated items. This
-/// contains the item's id, naturally, but also the item's name and
+/// contains the item's ID, naturally, but also the item's name and
 /// some other high-level details (like whether it is an associated
 /// type or method, and whether it is public). This allows other
-/// passes to find the impl they want without loading the id (which
+/// passes to find the impl they want without loading the ID (which
 /// means fewer edges in the incremental compilation graph).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct ImplItemRef {
@@ -2357,19 +2389,20 @@ pub struct ForeignItem {
     pub attrs: HirVec<Attribute>,
     pub node: ForeignItemKind,
     pub id: NodeId,
+    pub hir_id: HirId,
     pub span: Span,
     pub vis: Visibility,
 }
 
-/// An item within an `extern` block
+/// An item within an `extern` block.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum ForeignItemKind {
-    /// A foreign function
+    /// A foreign function.
     Fn(P<FnDecl>, HirVec<Ident>, Generics),
     /// A foreign static item (`static ext: u8`), with optional mutability
-    /// (the boolean is true when mutable)
+    /// (the boolean is true when mutable).
     Static(P<Ty>, bool),
-    /// A foreign type
+    /// A foreign type.
     Type,
 }
 
@@ -2430,6 +2463,8 @@ pub struct CodegenFnAttrs {
     pub flags: CodegenFnAttrFlags,
     /// Parsed representation of the `#[inline]` attribute
     pub inline: InlineAttr,
+    /// Parsed representation of the `#[optimize]` attribute
+    pub optimize: OptimizeAttr,
     /// The `#[export_name = "..."]` attribute, indicating a custom symbol a
     /// function should be exported under
     pub export_name: Option<Symbol>,
@@ -2451,36 +2486,37 @@ pub struct CodegenFnAttrs {
 bitflags! {
     #[derive(RustcEncodable, RustcDecodable)]
     pub struct CodegenFnAttrFlags: u32 {
-        /// #[cold], a hint to LLVM that this function, when called, is never on
-        /// the hot path
+        /// `#[cold]`: a hint to LLVM that this function, when called, is never on
+        /// the hot path.
         const COLD                      = 1 << 0;
-        /// #[allocator], a hint to LLVM that the pointer returned from this
-        /// function is never null
+        /// `#[allocator]`: a hint to LLVM that the pointer returned from this
+        /// function is never null.
         const ALLOCATOR                 = 1 << 1;
-        /// #[unwind], an indicator that this function may unwind despite what
-        /// its ABI signature may otherwise imply
+        /// `#[unwind]`: an indicator that this function may unwind despite what
+        /// its ABI signature may otherwise imply.
         const UNWIND                    = 1 << 2;
-        /// #[rust_allocator_nounwind], an indicator that an imported FFI
+        /// `#[rust_allocator_nounwind]`, an indicator that an imported FFI
         /// function will never unwind. Probably obsolete by recent changes with
         /// #[unwind], but hasn't been removed/migrated yet
         const RUSTC_ALLOCATOR_NOUNWIND  = 1 << 3;
-        /// #[naked], indicates to LLVM that no function prologue/epilogue
-        /// should be generated
+        /// `#[naked]`: an indicator to LLVM that no function prologue/epilogue
+        /// should be generated.
         const NAKED                     = 1 << 4;
-        /// #[no_mangle], the function's name should be the same as its symbol
+        /// `#[no_mangle]`: an indicator that the function's name should be the same
+        /// as its symbol.
         const NO_MANGLE                 = 1 << 5;
-        /// #[rustc_std_internal_symbol], and indicator that this symbol is a
+        /// `#[rustc_std_internal_symbol]`: an indicator that this symbol is a
         /// "weird symbol" for the standard library in that it has slightly
         /// different linkage, visibility, and reachability rules.
         const RUSTC_STD_INTERNAL_SYMBOL = 1 << 6;
-        /// #[no_debug], indicates that no debugging information should be
-        /// generated for this function by LLVM
+        /// `#[no_debug]`: an indicator that no debugging information should be
+        /// generated for this function by LLVM.
         const NO_DEBUG                  = 1 << 7;
-        /// #[thread_local], indicates a static is actually a thread local
+        /// `#[thread_local]`: indicates a static is actually a thread local
         /// piece of memory
         const THREAD_LOCAL              = 1 << 8;
-        /// #[used], indicates that LLVM can't eliminate this function (but the
-        /// linker can!)
+        /// `#[used]`: indicates that LLVM can't eliminate this function (but the
+        /// linker can!).
         const USED                      = 1 << 9;
     }
 }
@@ -2490,6 +2526,7 @@ impl CodegenFnAttrs {
         CodegenFnAttrs {
             flags: CodegenFnAttrFlags::empty(),
             inline: InlineAttr::None,
+            optimize: OptimizeAttr::None,
             export_name: None,
             link_name: None,
             target_features: vec![],
@@ -2498,7 +2535,7 @@ impl CodegenFnAttrs {
         }
     }
 
-    /// True if `#[inline]` or `#[inline(always)]` is present.
+    /// Returns `true` if `#[inline]` or `#[inline(always)]` is present.
     pub fn requests_inline(&self) -> bool {
         match self.inline {
             InlineAttr::Hint | InlineAttr::Always => true,
diff --git a/src/librustc/hir/pat_util.rs b/src/librustc/hir/pat_util.rs
index 4df71a8768ab2..312351ab850c2 100644
--- a/src/librustc/hir/pat_util.rs
+++ b/src/librustc/hir/pat_util.rs
@@ -1,6 +1,6 @@
-use hir::def::Def;
-use hir::def_id::DefId;
-use hir::{self, HirId, PatKind};
+use crate::hir::def::Def;
+use crate::hir::def_id::DefId;
+use crate::hir::{self, HirId, PatKind};
 use syntax::ast;
 use syntax_pos::Span;
 
@@ -64,26 +64,13 @@ impl hir::Pat {
         }
     }
 
-    pub fn is_const(&self) -> bool {
-        match self.node {
-            PatKind::Path(hir::QPath::TypeRelative(..)) => true,
-            PatKind::Path(hir::QPath::Resolved(_, ref path)) => {
-                match path.def {
-                    Def::Const(..) | Def::AssociatedConst(..) => true,
-                    _ => false
-                }
-            }
-            _ => false
-        }
-    }
-
     /// Call `f` on every "binding" in a pattern, e.g., on `a` in
     /// `match foo() { Some(a) => (), None => () }`
     pub fn each_binding<F>(&self, mut f: F)
         where F: FnMut(hir::BindingAnnotation, HirId, Span, ast::Ident),
     {
         self.walk(|p| {
-            if let PatKind::Binding(binding_mode, _, ident, _) = p.node {
+            if let PatKind::Binding(binding_mode, _, _, ident, _) = p.node {
                 f(binding_mode, p.hir_id, p.span, ident);
             }
             true
@@ -123,13 +110,13 @@ impl hir::Pat {
 
     pub fn simple_ident(&self) -> Option<ast::Ident> {
         match self.node {
-            PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ident, None) |
-            PatKind::Binding(hir::BindingAnnotation::Mutable, _, ident, None) => Some(ident),
+            PatKind::Binding(hir::BindingAnnotation::Unannotated, _, _, ident, None) |
+            PatKind::Binding(hir::BindingAnnotation::Mutable, _, _, ident, None) => Some(ident),
             _ => None,
         }
     }
 
-    /// Return variants that are necessary to exist for the pattern to match.
+    /// Returns variants that are necessary to exist for the pattern to match.
     pub fn necessary_variants(&self) -> Vec<DefId> {
         let mut variants = vec![];
         self.walk(|p| {
@@ -154,11 +141,9 @@ impl hir::Pat {
 
     /// Checks if the pattern contains any `ref` or `ref mut` bindings, and if
     /// yes whether it contains mutable or just immutables ones.
-    ///
-    /// FIXME(tschottdorf): this is problematic as the HIR is being scraped, but
-    /// ref bindings are be implicit after #42640 (default match binding modes).
-    ///
-    /// See #44848.
+    //
+    // FIXME(tschottdorf): this is problematic as the HIR is being scraped, but
+    // ref bindings are be implicit after #42640 (default match binding modes). See issue #44848.
     pub fn contains_explicit_ref_binding(&self) -> Option<hir::Mutability> {
         let mut result = None;
         self.each_binding(|annotation, _, _, _| {
diff --git a/src/librustc/hir/print.rs b/src/librustc/hir/print.rs
index d7acdefcc7d71..ece649cf1b882 100644
--- a/src/librustc/hir/print.rs
+++ b/src/librustc/hir/print.rs
@@ -11,9 +11,9 @@ use syntax::symbol::keywords;
 use syntax::util::parser::{self, AssocOp, Fixity};
 use syntax_pos::{self, BytePos, FileName};
 
-use hir;
-use hir::{PatKind, GenericBound, TraitBoundModifier, RangeEnd};
-use hir::{GenericParam, GenericParamKind, GenericArg};
+use crate::hir;
+use crate::hir::{PatKind, GenericBound, TraitBoundModifier, RangeEnd};
+use crate::hir::{GenericParam, GenericParamKind, GenericArg};
 
 use std::borrow::Cow;
 use std::cell::Cell;
@@ -992,14 +992,29 @@ impl<'a> State<'a> {
     pub fn print_stmt(&mut self, st: &hir::Stmt) -> io::Result<()> {
         self.maybe_print_comment(st.span.lo())?;
         match st.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                self.print_decl(&decl)?;
+            hir::StmtKind::Local(ref loc) => {
+                self.space_if_not_bol()?;
+                self.ibox(indent_unit)?;
+                self.word_nbsp("let")?;
+
+                self.ibox(indent_unit)?;
+                self.print_local_decl(&loc)?;
+                self.end()?;
+                if let Some(ref init) = loc.init {
+                    self.nbsp()?;
+                    self.word_space("=")?;
+                    self.print_expr(&init)?;
+                }
+                self.end()?
+            }
+            hir::StmtKind::Item(item) => {
+                self.ann.nested(self, Nested::Item(item))?
             }
-            hir::StmtKind::Expr(ref expr, _) => {
+            hir::StmtKind::Expr(ref expr) => {
                 self.space_if_not_bol()?;
                 self.print_expr(&expr)?;
             }
-            hir::StmtKind::Semi(ref expr, _) => {
+            hir::StmtKind::Semi(ref expr) => {
                 self.space_if_not_bol()?;
                 self.print_expr(&expr)?;
                 self.s.word(";")?;
@@ -1562,30 +1577,6 @@ impl<'a> State<'a> {
         Ok(())
     }
 
-    pub fn print_decl(&mut self, decl: &hir::Decl) -> io::Result<()> {
-        self.maybe_print_comment(decl.span.lo())?;
-        match decl.node {
-            hir::DeclKind::Local(ref loc) => {
-                self.space_if_not_bol()?;
-                self.ibox(indent_unit)?;
-                self.word_nbsp("let")?;
-
-                self.ibox(indent_unit)?;
-                self.print_local_decl(&loc)?;
-                self.end()?;
-                if let Some(ref init) = loc.init {
-                    self.nbsp()?;
-                    self.word_space("=")?;
-                    self.print_expr(&init)?;
-                }
-                self.end()
-            }
-            hir::DeclKind::Item(item) => {
-                self.ann.nested(self, Nested::Item(item))
-            }
-        }
-    }
-
     pub fn print_usize(&mut self, i: usize) -> io::Result<()> {
         self.s.word(i.to_string())
     }
@@ -1720,31 +1711,25 @@ impl<'a> State<'a> {
                 }
             };
 
-            let mut types = vec![];
-            let mut elide_lifetimes = true;
-            for arg in &generic_args.args {
-                match arg {
-                    GenericArg::Lifetime(lt) => {
-                        if !lt.is_elided() {
-                            elide_lifetimes = false;
-                        }
-                    }
-                    GenericArg::Type(ty) => {
-                        types.push(ty);
-                    }
+            let mut nonelided_generic_args: bool = false;
+            let elide_lifetimes = generic_args.args.iter().all(|arg| match arg {
+                GenericArg::Lifetime(lt) => lt.is_elided(),
+                _ => {
+                    nonelided_generic_args = true;
+                    true
                 }
-            }
-            if !elide_lifetimes {
+            });
+
+            if nonelided_generic_args {
                 start_or_comma(self)?;
                 self.commasep(Inconsistent, &generic_args.args, |s, generic_arg| {
                     match generic_arg {
-                        GenericArg::Lifetime(lt) => s.print_lifetime(lt),
+                        GenericArg::Lifetime(lt) if !elide_lifetimes => s.print_lifetime(lt),
+                        GenericArg::Lifetime(_) => Ok(()),
                         GenericArg::Type(ty) => s.print_type(ty),
+                        GenericArg::Const(ct) => s.print_anon_const(&ct.value),
                     }
                 })?;
-            } else if !types.is_empty() {
-                start_or_comma(self)?;
-                self.commasep(Inconsistent, &types, |s, ty| s.print_type(&ty))?;
             }
 
             // FIXME(eddyb) This would leak into error messages, e.g.:
@@ -1777,7 +1762,7 @@ impl<'a> State<'a> {
         // is that it doesn't matter
         match pat.node {
             PatKind::Wild => self.s.word("_")?,
-            PatKind::Binding(binding_mode, _, ident, ref sub) => {
+            PatKind::Binding(binding_mode, _, _, ident, ref sub) => {
                 match binding_mode {
                     hir::BindingAnnotation::Ref => {
                         self.word_nbsp("ref")?;
@@ -2115,7 +2100,12 @@ impl<'a> State<'a> {
     }
 
     pub fn print_generic_param(&mut self, param: &GenericParam) -> io::Result<()> {
+        if let GenericParamKind::Const { .. } = param.kind {
+            self.word_space("const")?;
+        }
+
         self.print_ident(param.name.ident())?;
+
         match param.kind {
             GenericParamKind::Lifetime { .. } => {
                 let mut sep = ":";
@@ -2142,6 +2132,10 @@ impl<'a> State<'a> {
                     _ => Ok(()),
                 }
             }
+            GenericParamKind::Const { ref ty } => {
+                self.word_space(":")?;
+                self.print_type(ty)
+            }
         }
     }
 
@@ -2255,6 +2249,7 @@ impl<'a> State<'a> {
             params: hir::HirVec::new(),
             where_clause: hir::WhereClause {
                 id: ast::DUMMY_NODE_ID,
+                hir_id: hir::DUMMY_HIR_ID,
                 predicates: hir::HirVec::new(),
             },
             span: syntax_pos::DUMMY_SP,
@@ -2401,23 +2396,15 @@ fn expr_requires_semi_to_be_stmt(e: &hir::Expr) -> bool {
 /// seen the semicolon, and thus don't need another.
 fn stmt_ends_with_semi(stmt: &hir::StmtKind) -> bool {
     match *stmt {
-        hir::StmtKind::Decl(ref d, _) => {
-            match d.node {
-                hir::DeclKind::Local(_) => true,
-                hir::DeclKind::Item(_) => false,
-            }
-        }
-        hir::StmtKind::Expr(ref e, _) => {
-            expr_requires_semi_to_be_stmt(&e)
-        }
-        hir::StmtKind::Semi(..) => {
-            false
-        }
+        hir::StmtKind::Local(_) => true,
+        hir::StmtKind::Item(_) => false,
+        hir::StmtKind::Expr(ref e) => expr_requires_semi_to_be_stmt(&e),
+        hir::StmtKind::Semi(..) => false,
     }
 }
 
 fn bin_op_to_assoc_op(op: hir::BinOpKind) -> AssocOp {
-    use hir::BinOpKind::*;
+    use crate::hir::BinOpKind::*;
     match op {
         Add => AssocOp::Add,
         Sub => AssocOp::Subtract,
diff --git a/src/librustc/ich/hcx.rs b/src/librustc/ich/hcx.rs
index d5c9d9ff16dcb..e60fdd62debd1 100644
--- a/src/librustc/ich/hcx.rs
+++ b/src/librustc/ich/hcx.rs
@@ -1,11 +1,11 @@
-use hir;
-use hir::def_id::{DefId, DefIndex};
-use hir::map::DefPathHash;
-use hir::map::definitions::Definitions;
-use ich::{self, CachingSourceMapView, Fingerprint};
-use middle::cstore::CrateStore;
-use ty::{TyCtxt, fast_reject};
-use session::Session;
+use crate::hir;
+use crate::hir::def_id::{DefId, DefIndex};
+use crate::hir::map::DefPathHash;
+use crate::hir::map::definitions::Definitions;
+use crate::ich::{self, CachingSourceMapView, Fingerprint};
+use crate::middle::cstore::CrateStore;
+use crate::ty::{TyCtxt, fast_reject};
+use crate::session::Session;
 
 use std::cmp::Ord;
 use std::hash as std_hash;
@@ -218,7 +218,7 @@ impl<'a> StableHashingContextProvider<'a> for StableHashingContext<'a> {
     }
 }
 
-impl<'a> ::dep_graph::DepGraphSafe for StableHashingContext<'a> {
+impl<'a> crate::dep_graph::DepGraphSafe for StableHashingContext<'a> {
 }
 
 
diff --git a/src/librustc/ich/impls_cstore.rs b/src/librustc/ich/impls_cstore.rs
index fdea62a1dd8f6..17ed1a79d45e0 100644
--- a/src/librustc/ich/impls_cstore.rs
+++ b/src/librustc/ich/impls_cstore.rs
@@ -1,23 +1,21 @@
 //! This module contains `HashStable` implementations for various data types
 //! from rustc::middle::cstore in no particular order.
 
-use middle;
-
-impl_stable_hash_for!(enum middle::cstore::DepKind {
+impl_stable_hash_for!(enum crate::middle::cstore::DepKind {
     UnexportedMacrosOnly,
     MacrosOnly,
     Implicit,
     Explicit
 });
 
-impl_stable_hash_for!(enum middle::cstore::NativeLibraryKind {
+impl_stable_hash_for!(enum crate::middle::cstore::NativeLibraryKind {
     NativeStatic,
     NativeStaticNobundle,
     NativeFramework,
     NativeUnknown
 });
 
-impl_stable_hash_for!(struct middle::cstore::NativeLibrary {
+impl_stable_hash_for!(struct crate::middle::cstore::NativeLibrary {
     kind,
     name,
     cfg,
@@ -25,30 +23,30 @@ impl_stable_hash_for!(struct middle::cstore::NativeLibrary {
     wasm_import_module
 });
 
-impl_stable_hash_for!(struct middle::cstore::ForeignModule {
+impl_stable_hash_for!(struct crate::middle::cstore::ForeignModule {
     foreign_items,
     def_id
 });
 
-impl_stable_hash_for!(enum middle::cstore::LinkagePreference {
+impl_stable_hash_for!(enum crate::middle::cstore::LinkagePreference {
     RequireDynamic,
     RequireStatic
 });
 
-impl_stable_hash_for!(struct middle::cstore::ExternCrate {
+impl_stable_hash_for!(struct crate::middle::cstore::ExternCrate {
     src,
     span,
     path_len,
     direct
 });
 
-impl_stable_hash_for!(enum middle::cstore::ExternCrateSource {
+impl_stable_hash_for!(enum crate::middle::cstore::ExternCrateSource {
     Extern(def_id),
     Use,
     Path,
 });
 
-impl_stable_hash_for!(struct middle::cstore::CrateSource {
+impl_stable_hash_for!(struct crate::middle::cstore::CrateSource {
     dylib,
     rlib,
     rmeta
diff --git a/src/librustc/ich/impls_hir.rs b/src/librustc/ich/impls_hir.rs
index 8ff60e5f56225..727c441b0e8db 100644
--- a/src/librustc/ich/impls_hir.rs
+++ b/src/librustc/ich/impls_hir.rs
@@ -1,10 +1,10 @@
 //! This module contains `HashStable` implementations for various HIR data
 //! types in no particular order.
 
-use hir;
-use hir::map::DefPathHash;
-use hir::def_id::{DefId, LocalDefId, CrateNum, CRATE_DEF_INDEX};
-use ich::{StableHashingContext, NodeIdHashingMode, Fingerprint};
+use crate::hir;
+use crate::hir::map::DefPathHash;
+use crate::hir::def_id::{DefId, LocalDefId, CrateNum, CRATE_DEF_INDEX};
+use crate::ich::{StableHashingContext, NodeIdHashingMode, Fingerprint};
 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
                                            StableHasher, StableHasherResult};
 use std::mem;
@@ -153,12 +153,13 @@ impl_stable_hash_for!(enum hir::LifetimeName {
     Error,
 });
 
-impl_stable_hash_for!(struct hir::Label {
+impl_stable_hash_for!(struct ast::Label {
     ident
 });
 
 impl_stable_hash_for!(struct hir::Lifetime {
     id,
+    hir_id,
     span,
     name
 });
@@ -172,14 +173,21 @@ impl_stable_hash_for!(struct hir::Path {
 impl_stable_hash_for!(struct hir::PathSegment {
     ident -> (ident.name),
     id,
+    hir_id,
     def,
     infer_types,
     args
 });
 
+impl_stable_hash_for!(struct hir::ConstArg {
+    value,
+    span,
+});
+
 impl_stable_hash_for!(enum hir::GenericArg {
     Lifetime(lt),
-    Type(ty)
+    Type(ty),
+    Const(ct),
 });
 
 impl_stable_hash_for!(struct hir::GenericArgs {
@@ -200,6 +208,7 @@ impl_stable_hash_for!(enum hir::TraitBoundModifier {
 
 impl_stable_hash_for!(struct hir::GenericParam {
     id,
+    hir_id,
     name,
     pure_wrt_drop,
     attrs,
@@ -228,6 +237,9 @@ impl<'a> HashStable<StableHashingContext<'a>> for hir::GenericParamKind {
                 default.hash_stable(hcx, hasher);
                 synthetic.hash_stable(hcx, hasher);
             }
+            hir::GenericParamKind::Const { ref ty } => {
+                ty.hash_stable(hcx, hasher);
+            }
         }
     }
 }
@@ -244,6 +256,7 @@ impl_stable_hash_for!(enum hir::SyntheticTyParamKind {
 
 impl_stable_hash_for!(struct hir::WhereClause {
     id,
+    hir_id,
     predicates
 });
 
@@ -268,6 +281,7 @@ impl_stable_hash_for!(struct hir::WhereRegionPredicate {
 
 impl_stable_hash_for!(struct hir::WhereEqPredicate {
     id,
+    hir_id,
     span,
     lhs_ty,
     rhs_ty
@@ -285,6 +299,7 @@ impl_stable_hash_for!(struct hir::MethodSig {
 
 impl_stable_hash_for!(struct hir::TypeBinding {
     id,
+    hir_id,
     ident -> (ident.name),
     ty,
     span
@@ -397,6 +412,7 @@ impl_stable_hash_for!(struct hir::MacroDef {
     vis,
     attrs,
     id,
+    hir_id,
     span,
     legacy,
     body
@@ -423,6 +439,7 @@ impl_stable_hash_for_spanned!(hir::FieldPat);
 
 impl_stable_hash_for!(struct hir::FieldPat {
     id -> _,
+    hir_id -> _,
     ident -> (ident.name),
     pat,
     is_shorthand,
@@ -442,7 +459,7 @@ impl_stable_hash_for!(enum hir::RangeEnd {
 
 impl_stable_hash_for!(enum hir::PatKind {
     Wild,
-    Binding(binding_mode, var, name, sub),
+    Binding(binding_mode, var, hir_id, name, sub),
     Struct(path, field_pats, dotdot),
     TupleStruct(path, field_pats, dotdot),
     Path(path),
@@ -483,7 +500,13 @@ impl_stable_hash_for!(enum hir::UnOp {
     UnNeg
 });
 
-impl_stable_hash_for_spanned!(hir::StmtKind);
+impl_stable_hash_for!(struct hir::Stmt {
+    id,
+    hir_id,
+    node,
+    span,
+});
+
 
 impl_stable_hash_for!(struct hir::Local {
     pat,
@@ -496,12 +519,6 @@ impl_stable_hash_for!(struct hir::Local {
     source
 });
 
-impl_stable_hash_for_spanned!(hir::DeclKind);
-impl_stable_hash_for!(enum hir::DeclKind {
-    Local(local),
-    Item(item_id)
-});
-
 impl_stable_hash_for!(struct hir::Arm {
     attrs,
     pats,
@@ -515,6 +532,7 @@ impl_stable_hash_for!(enum hir::Guard {
 
 impl_stable_hash_for!(struct hir::Field {
     id -> _,
+    hir_id -> _,
     ident,
     expr,
     span,
@@ -610,7 +628,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for hir::MatchSource {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use hir::MatchSource;
+        use crate::hir::MatchSource;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match *self {
@@ -837,14 +855,15 @@ impl_stable_hash_for!(struct hir::StructField {
     ident -> (ident.name),
     vis,
     id,
+    hir_id,
     ty,
     attrs
 });
 
 impl_stable_hash_for!(enum hir::VariantData {
-    Struct(fields, id),
-    Tuple(fields, id),
-    Unit(id)
+    Struct(fields, id, hir_id),
+    Tuple(fields, id, hir_id),
+    Unit(id, hir_id)
 });
 
 impl<'a> HashStable<StableHashingContext<'a>> for hir::Item {
@@ -930,6 +949,7 @@ impl_stable_hash_for!(struct hir::ForeignItem {
     attrs,
     node,
     id,
+    hir_id,
     span,
     vis
 });
@@ -941,9 +961,10 @@ impl_stable_hash_for!(enum hir::ForeignItemKind {
 });
 
 impl_stable_hash_for!(enum hir::StmtKind {
-    Decl(decl, id),
-    Expr(expr, id),
-    Semi(expr, id)
+    Local(local),
+    Item(item_id),
+    Expr(expr),
+    Semi(expr)
 });
 
 impl_stable_hash_for!(struct hir::Arg {
@@ -977,8 +998,8 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::BodyId {
     fn to_stable_hash_key(&self,
                           hcx: &StableHashingContext<'a>)
                           -> (DefPathHash, hir::ItemLocalId) {
-        let hir::BodyId { node_id } = *self;
-        node_id.to_stable_hash_key(hcx)
+        let hir::BodyId { hir_id } = *self;
+        hir_id.to_stable_hash_key(hcx)
     }
 }
 
@@ -1034,6 +1055,7 @@ impl_stable_hash_for!(enum hir::def::Def {
     AssociatedExistential(def_id),
     PrimTy(prim_ty),
     TyParam(def_id),
+    ConstParam(def_id),
     SelfTy(trait_def_id, impl_def_id),
     ForeignTy(def_id),
     Fn(def_id),
@@ -1104,12 +1126,12 @@ impl_stable_hash_for!(struct hir::def::Export {
     span
 });
 
-impl_stable_hash_for!(struct ::middle::lib_features::LibFeatures {
+impl_stable_hash_for!(struct crate::middle::lib_features::LibFeatures {
     stable,
     unstable
 });
 
-impl<'a> HashStable<StableHashingContext<'a>> for ::middle::lang_items::LangItem {
+impl<'a> HashStable<StableHashingContext<'a>> for crate::middle::lang_items::LangItem {
     fn hash_stable<W: StableHasherResult>(&self,
                                           _: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
@@ -1117,7 +1139,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for ::middle::lang_items::LangItem
     }
 }
 
-impl_stable_hash_for!(struct ::middle::lang_items::LanguageItems {
+impl_stable_hash_for!(struct crate::middle::lang_items::LanguageItems {
     items,
     missing
 });
@@ -1159,6 +1181,7 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for hir::TraitCandidate {
 impl_stable_hash_for!(struct hir::CodegenFnAttrs {
     flags,
     inline,
+    optimize,
     export_name,
     link_name,
     target_features,
@@ -1183,6 +1206,14 @@ impl<'hir> HashStable<StableHashingContext<'hir>> for attr::InlineAttr {
     }
 }
 
+impl<'hir> HashStable<StableHashingContext<'hir>> for attr::OptimizeAttr {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'hir>,
+                                          hasher: &mut StableHasher<W>) {
+        mem::discriminant(self).hash_stable(hcx, hasher);
+    }
+}
+
 impl_stable_hash_for!(struct hir::Freevar {
     def,
     span
diff --git a/src/librustc/ich/impls_mir.rs b/src/librustc/ich/impls_mir.rs
index 002ac7cc7a9bb..51fc78ffc8669 100644
--- a/src/librustc/ich/impls_mir.rs
+++ b/src/librustc/ich/impls_mir.rs
@@ -1,8 +1,8 @@
 //! This module contains `HashStable` implementations for various MIR data
 //! types in no particular order.
 
-use ich::StableHashingContext;
-use mir;
+use crate::ich::StableHashingContext;
+use crate::mir;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
 use std::mem;
diff --git a/src/librustc/ich/impls_misc.rs b/src/librustc/ich/impls_misc.rs
index f79adc8109a7f..8a388fafce5e8 100644
--- a/src/librustc/ich/impls_misc.rs
+++ b/src/librustc/ich/impls_misc.rs
@@ -1,7 +1,7 @@
 //! This module contains `HashStable` implementations for various data types
 //! that don't fit into any of the other impls_xxx modules.
 
-impl_stable_hash_for!(enum ::session::search_paths::PathKind {
+impl_stable_hash_for!(enum crate::session::search_paths::PathKind {
     Native,
     Crate,
     Dependency,
diff --git a/src/librustc/ich/impls_syntax.rs b/src/librustc/ich/impls_syntax.rs
index 70ec72d73bc6c..f34423ccca655 100644
--- a/src/librustc/ich/impls_syntax.rs
+++ b/src/librustc/ich/impls_syntax.rs
@@ -1,7 +1,7 @@
 //! This module contains `HashStable` implementations for various data types
 //! from libsyntax in no particular order.
 
-use ich::StableHashingContext;
+use crate::ich::StableHashingContext;
 
 use std::hash as std_hash;
 use std::mem;
@@ -13,7 +13,7 @@ use syntax::symbol::{InternedString, LocalInternedString};
 use syntax::tokenstream;
 use syntax_pos::SourceFile;
 
-use hir::def_id::{DefId, CrateNum, CRATE_DEF_INDEX};
+use crate::hir::def_id::{DefId, CrateNum, CRATE_DEF_INDEX};
 
 use smallvec::SmallVec;
 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
@@ -147,7 +147,7 @@ for ::syntax::attr::StabilityLevel {
     }
 }
 
-impl_stable_hash_for!(struct ::syntax::attr::RustcDeprecation { since, reason });
+impl_stable_hash_for!(struct ::syntax::attr::RustcDeprecation { since, reason, suggestion });
 
 
 impl_stable_hash_for!(enum ::syntax::attr::IntType {
@@ -164,6 +164,7 @@ impl_stable_hash_for!(enum ::syntax::ast::LitIntType {
 impl_stable_hash_for_spanned!(::syntax::ast::LitKind);
 impl_stable_hash_for!(enum ::syntax::ast::LitKind {
     Str(value, style),
+    Err(value),
     ByteStr(value),
     Byte(value),
     Char(value),
@@ -258,7 +259,7 @@ for tokenstream::TokenTree {
             tokenstream::TokenTree::Delimited(span, delim, ref tts) => {
                 span.hash_stable(hcx, hasher);
                 std_hash::Hash::hash(&delim, hasher);
-                for sub_tt in tts.stream().trees() {
+                for sub_tt in tts.trees() {
                     sub_tt.hash_stable(hcx, hasher);
                 }
             }
@@ -329,6 +330,7 @@ fn hash_token<'a, 'gcx, W: StableHasherResult>(
             match *lit {
                 token::Lit::Byte(val) |
                 token::Lit::Char(val) |
+                token::Lit::Err(val) |
                 token::Lit::Integer(val) |
                 token::Lit::Float(val) |
                 token::Lit::Str_(val) |
diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index ef7fb0128ef4b..53ed0bfb12ee9 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -1,18 +1,18 @@
 //! This module contains `HashStable` implementations for various data types
 //! from rustc::ty in no particular order.
 
-use ich::{Fingerprint, StableHashingContext, NodeIdHashingMode};
+use crate::ich::{Fingerprint, StableHashingContext, NodeIdHashingMode};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
                                            StableHasher, StableHasherResult};
 use std::cell::RefCell;
 use std::hash as std_hash;
 use std::mem;
-use middle::region;
-use infer;
-use traits;
-use ty;
-use mir;
+use crate::middle::region;
+use crate::infer;
+use crate::traits;
+use crate::ty;
+use crate::mir;
 
 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>>
 for &'gcx ty::List<T>
@@ -206,6 +206,10 @@ impl<'gcx> HashStable<StableHashingContext<'gcx>> for ty::adjustment::AutoBorrow
     }
 }
 
+impl_stable_hash_for!(tuple_struct ty::util::NeedsDrop { value });
+
+impl_stable_hash_for!(tuple_struct ty::AdtSizedConstraint<'tcx> { list });
+
 impl_stable_hash_for!(struct ty::UpvarPath { hir_id });
 
 impl_stable_hash_for!(struct ty::UpvarId { var_path, closure_expr_id });
@@ -233,6 +237,11 @@ impl_stable_hash_for!(struct ty::FnSig<'tcx> {
     abi
 });
 
+impl_stable_hash_for!(struct ty::ResolvedOpaqueTy<'tcx> {
+    concrete_type,
+    substs
+});
+
 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ty::Binder<T>
     where T: HashStable<StableHashingContext<'a>>
 {
@@ -302,11 +311,11 @@ impl_stable_hash_for!(struct ty::FieldDef {
 impl_stable_hash_for!(
     impl<'tcx> for enum mir::interpret::ConstValue<'tcx> [ mir::interpret::ConstValue ] {
         Scalar(val),
-        ScalarPair(a, b),
+        Slice(a, b),
         ByRef(id, alloc, offset),
     }
 );
-impl_stable_hash_for!(struct ::mir::interpret::RawConst<'tcx> {
+impl_stable_hash_for!(struct crate::mir::interpret::RawConst<'tcx> {
     alloc_id,
     ty,
 });
@@ -512,20 +521,22 @@ impl_stable_hash_for!(enum ty::GenericParamDefKind {
 });
 
 impl_stable_hash_for!(
-    impl<T> for enum ::middle::resolve_lifetime::Set1<T> [ ::middle::resolve_lifetime::Set1 ] {
+    impl<T> for enum crate::middle::resolve_lifetime::Set1<T>
+        [ crate::middle::resolve_lifetime::Set1 ]
+    {
         Empty,
         Many,
         One(value),
     }
 );
 
-impl_stable_hash_for!(enum ::middle::resolve_lifetime::LifetimeDefOrigin {
+impl_stable_hash_for!(enum crate::middle::resolve_lifetime::LifetimeDefOrigin {
     ExplicitOrElided,
     InBand,
     Error,
 });
 
-impl_stable_hash_for!(enum ::middle::resolve_lifetime::Region {
+impl_stable_hash_for!(enum crate::middle::resolve_lifetime::Region {
     Static,
     EarlyBound(index, decl, is_in_band),
     LateBound(db_index, decl, is_in_band),
@@ -547,9 +558,9 @@ impl_stable_hash_for!(enum ty::cast::CastKind {
     FnPtrAddrCast
 });
 
-impl_stable_hash_for!(struct ::middle::region::Scope { id, data });
+impl_stable_hash_for!(struct crate::middle::region::Scope { id, data });
 
-impl_stable_hash_for!(enum ::middle::region::ScopeData {
+impl_stable_hash_for!(enum crate::middle::region::ScopeData {
     Node,
     CallSite,
     Arguments,
@@ -588,7 +599,7 @@ for ty::TyKind<'gcx>
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use ty::TyKind::*;
+        use crate::ty::TyKind::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match *self {
@@ -882,7 +893,7 @@ impl_stable_hash_for!(enum traits::Reveal {
     All
 });
 
-impl_stable_hash_for!(enum ::middle::privacy::AccessLevel {
+impl_stable_hash_for!(enum crate::middle::privacy::AccessLevel {
     ReachableFromImplTrait,
     Reachable,
     Exported,
@@ -890,12 +901,12 @@ impl_stable_hash_for!(enum ::middle::privacy::AccessLevel {
 });
 
 impl<'a> HashStable<StableHashingContext<'a>>
-for ::middle::privacy::AccessLevels {
+for crate::middle::privacy::AccessLevels {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
         hcx.with_node_id_hashing_mode(NodeIdHashingMode::HashDefPath, |hcx| {
-            let ::middle::privacy::AccessLevels {
+            let crate::middle::privacy::AccessLevels {
                 ref map
             } = *self;
 
@@ -908,14 +919,14 @@ impl_stable_hash_for!(struct ty::CrateInherentImpls {
     inherent_impls
 });
 
-impl_stable_hash_for!(enum ::session::CompileIncomplete {
+impl_stable_hash_for!(enum crate::session::CompileIncomplete {
     Stopped,
     Errored(error_reported)
 });
 
-impl_stable_hash_for!(struct ::util::common::ErrorReported {});
+impl_stable_hash_for!(struct crate::util::common::ErrorReported {});
 
-impl_stable_hash_for!(tuple_struct ::middle::reachable::ReachableSet {
+impl_stable_hash_for!(tuple_struct crate::middle::reachable::ReachableSet {
     reachable_set
 });
 
@@ -924,7 +935,7 @@ for traits::Vtable<'gcx, N> where N: HashStable<StableHashingContext<'a>> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::Vtable::*;
+        use crate::traits::Vtable::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
 
@@ -1105,7 +1116,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::WhereClause<'tcx
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::WhereClause::*;
+        use crate::traits::WhereClause::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1121,7 +1132,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::WellFormed<'tcx>
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::WellFormed::*;
+        use crate::traits::WellFormed::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1135,7 +1146,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::FromEnv<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::FromEnv::*;
+        use crate::traits::FromEnv::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1149,7 +1160,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::DomainGoal<'tcx>
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::DomainGoal::*;
+        use crate::traits::DomainGoal::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1165,7 +1176,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::Goal<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::GoalKind::*;
+        use crate::traits::GoalKind::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1208,7 +1219,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for traits::Clause<'tcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use traits::Clause::*;
+        use crate::traits::Clause::*;
 
         mem::discriminant(self).hash_stable(hcx, hasher);
         match self {
@@ -1240,16 +1251,22 @@ impl_stable_hash_for!(
     }
 );
 
-impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::UserTypeAnnotation<'gcx> {
+impl_stable_hash_for!(
+    struct ty::CanonicalUserTypeAnnotation<'tcx> {
+        user_ty, span, inferred_ty
+    }
+);
+
+impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::UserType<'gcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
         mem::discriminant(self).hash_stable(hcx, hasher);
         match *self {
-            ty::UserTypeAnnotation::Ty(ref ty) => {
+            ty::UserType::Ty(ref ty) => {
                 ty.hash_stable(hcx, hasher);
             }
-            ty::UserTypeAnnotation::TypeOf(ref def_id, ref substs) => {
+            ty::UserType::TypeOf(ref def_id, ref substs) => {
                 def_id.hash_stable(hcx, hasher);
                 substs.hash_stable(hcx, hasher);
             }
diff --git a/src/librustc/infer/at.rs b/src/librustc/infer/at.rs
index 328d518ca66aa..34cd3ae5427e0 100644
--- a/src/librustc/infer/at.rs
+++ b/src/librustc/infer/at.rs
@@ -1,6 +1,6 @@
-//! A nice interface for working with the infcx.  The basic idea is to
+//! A nice interface for working with the infcx. The basic idea is to
 //! do `infcx.at(cause, param_env)`, which sets the "cause" of the
-//! operation as well as the surrounding parameter environment.  Then
+//! operation as well as the surrounding parameter environment. Then
 //! you can do something like `.sub(a, b)` or `.eq(a, b)` to create a
 //! subtype or equality relationship respectively. The first argument
 //! is always the "expected" output from the POV of diagnostics.
@@ -27,7 +27,7 @@
 
 use super::*;
 
-use ty::relate::{Relate, TypeRelation};
+use crate::ty::relate::{Relate, TypeRelation};
 
 pub struct At<'a, 'gcx: 'tcx, 'tcx: 'a> {
     pub infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
@@ -78,7 +78,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Make `a <: b` where `a` may or may not be expected
+    /// Makes `a <: b`, where `a` may or may not be expected.
     pub fn sub_exp<T>(self,
                       a_is_expected: bool,
                       a: T,
@@ -89,7 +89,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         self.trace_exp(a_is_expected, a, b).sub(&a, &b)
     }
 
-    /// Make `actual <: expected`. For example, if type-checking a
+    /// Makes `actual <: expected`. For example, if type-checking a
     /// call like `foo(x)`, where `foo: fn(i32)`, you might have
     /// `sup(i32, x)`, since the "expected" type is the type that
     /// appears in the signature.
@@ -102,7 +102,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         self.sub_exp(false, actual, expected)
     }
 
-    /// Make `expected <: actual`
+    /// Makes `expected <: actual`.
     pub fn sub<T>(self,
                   expected: T,
                   actual: T)
@@ -112,7 +112,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         self.sub_exp(true, expected, actual)
     }
 
-    /// Make `expected <: actual`
+    /// Makes `expected <: actual`.
     pub fn eq_exp<T>(self,
                      a_is_expected: bool,
                      a: T,
@@ -123,7 +123,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         self.trace_exp(a_is_expected, a, b).eq(&a, &b)
     }
 
-    /// Make `expected <: actual`
+    /// Makes `expected <: actual`.
     pub fn eq<T>(self,
                  expected: T,
                  actual: T)
@@ -155,7 +155,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Compute the least-upper-bound, or mutual supertype, of two
+    /// Computes the least-upper-bound, or mutual supertype, of two
     /// values. The order of the arguments doesn't matter, but since
     /// this can result in an error (e.g., if asked to compute LUB of
     /// u32 and i32), it is meaningful to call one of them the
@@ -169,7 +169,7 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
         self.trace(expected, actual).lub(&expected, &actual)
     }
 
-    /// Compute the greatest-lower-bound, or mutual subtype, of two
+    /// Computes the greatest-lower-bound, or mutual subtype, of two
     /// values. As with `lub` order doesn't matter, except for error
     /// cases.
     pub fn glb<T>(self,
@@ -210,9 +210,9 @@ impl<'a, 'gcx, 'tcx> At<'a, 'gcx, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> Trace<'a, 'gcx, 'tcx> {
-    /// Make `a <: b` where `a` may or may not be expected (if
+    /// Makes `a <: b` where `a` may or may not be expected (if
     /// `a_is_expected` is true, then `a` is expected).
-    /// Make `expected <: actual`
+    /// Makes `expected <: actual`.
     pub fn sub<T>(self,
                   a: &T,
                   b: &T)
@@ -229,7 +229,7 @@ impl<'a, 'gcx, 'tcx> Trace<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// Make `a == b`; the expectation is set by the call to
+    /// Makes `a == b`; the expectation is set by the call to
     /// `trace()`.
     pub fn eq<T>(self,
                  a: &T,
diff --git a/src/librustc/infer/canonical/canonicalizer.rs b/src/librustc/infer/canonical/canonicalizer.rs
index 408cba42ae04b..d06334c3ba643 100644
--- a/src/librustc/infer/canonical/canonicalizer.rs
+++ b/src/librustc/infer/canonical/canonicalizer.rs
@@ -5,15 +5,15 @@
 //!
 //! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
 
-use infer::canonical::{
+use crate::infer::canonical::{
     Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, Canonicalized,
     OriginalQueryValues,
 };
-use infer::InferCtxt;
+use crate::infer::InferCtxt;
 use std::sync::atomic::Ordering;
-use ty::fold::{TypeFoldable, TypeFolder};
-use ty::subst::Kind;
-use ty::{self, BoundVar, Lift, List, Ty, TyCtxt, TypeFlags};
+use crate::ty::fold::{TypeFoldable, TypeFolder};
+use crate::ty::subst::Kind;
+use crate::ty::{self, BoundVar, Lift, List, Ty, TyCtxt, TypeFlags};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
@@ -112,14 +112,14 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     }
 
     /// A hacky variant of `canonicalize_query` that does not
-    /// canonicalize `'static`.  Unfortunately, the existing leak
+    /// canonicalize `'static`. Unfortunately, the existing leak
     /// check treaks `'static` differently in some cases (see also
     /// #33684), so if we are performing an operation that may need to
     /// prove "leak-check" related things, we leave `'static`
     /// alone.
-    ///
-    /// FIXME(#48536) -- once we have universes, we can remove this and just use
-    /// `canonicalize_query`.
+    //
+    // FIXME(#48536): once we have universes, we can remove this and just use
+    // `canonicalize_query`.
     pub fn canonicalize_hr_query_hack<V>(
         &self,
         value: &V,
@@ -595,7 +595,7 @@ impl<'cx, 'gcx, 'tcx> Canonicalizer<'cx, 'gcx, 'tcx> {
             .var_universe(vid)
     }
 
-    /// Create a canonical variable (with the given `info`)
+    /// Creates a canonical variable (with the given `info`)
     /// representing the region `r`; return a region referencing it.
     fn canonical_var_for_region(
         &mut self,
diff --git a/src/librustc/infer/canonical/mod.rs b/src/librustc/infer/canonical/mod.rs
index eaf72f5a68710..613e153ae33d4 100644
--- a/src/librustc/infer/canonical/mod.rs
+++ b/src/librustc/infer/canonical/mod.rs
@@ -21,16 +21,16 @@
 //!
 //! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
 
-use infer::{InferCtxt, RegionVariableOrigin, TypeVariableOrigin};
+use crate::infer::{InferCtxt, RegionVariableOrigin, TypeVariableOrigin};
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::sync::Lrc;
 use serialize::UseSpecializedDecodable;
 use smallvec::SmallVec;
 use std::ops::Index;
 use syntax::source_map::Span;
-use ty::fold::TypeFoldable;
-use ty::subst::Kind;
-use ty::{self, BoundVar, Lift, List, Region, TyCtxt};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::subst::Kind;
+use crate::ty::{self, BoundVar, Lift, List, Region, TyCtxt};
 
 mod canonicalizer;
 
@@ -289,7 +289,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     ///
     /// This is only meant to be invoked as part of constructing an
     /// inference context at the start of a query (see
-    /// `InferCtxtBuilder::enter_with_canonical`).  It basically
+    /// `InferCtxtBuilder::enter_with_canonical`). It basically
     /// brings the canonical value "into scope" within your new infcx.
     ///
     /// At the end of processing, the substitution S (once
@@ -393,14 +393,14 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 }
 
 CloneTypeFoldableAndLiftImpls! {
-    ::infer::canonical::Certainty,
-    ::infer::canonical::CanonicalVarInfo,
-    ::infer::canonical::CanonicalVarKind,
+    crate::infer::canonical::Certainty,
+    crate::infer::canonical::CanonicalVarInfo,
+    crate::infer::canonical::CanonicalVarKind,
 }
 
 CloneTypeFoldableImpls! {
     for <'tcx> {
-        ::infer::canonical::CanonicalVarInfos<'tcx>,
+        crate::infer::canonical::CanonicalVarInfos<'tcx>,
     }
 }
 
@@ -424,14 +424,14 @@ impl<'tcx> CanonicalVarValues<'tcx> {
         self.var_values.len()
     }
 
-    /// Make an identity substitution from this one: each bound var
+    /// Makes an identity substitution from this one: each bound var
     /// is matched to the same bound var, preserving the original kinds.
     /// For example, if we have:
     /// `self.var_values == [Type(u32), Lifetime('a), Type(u64)]`
     /// we'll return a substitution `subst` with:
     /// `subst.var_values == [Type(^0), Lifetime(^1), Type(^2)]`.
     pub fn make_identity<'a>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Self {
-        use ty::subst::UnpackedKind;
+        use crate::ty::subst::UnpackedKind;
 
         CanonicalVarValues {
             var_values: self.var_values.iter()
diff --git a/src/librustc/infer/canonical/query_response.rs b/src/librustc/infer/canonical/query_response.rs
index 7f113f07276d8..aef0152b6ed73 100644
--- a/src/librustc/infer/canonical/query_response.rs
+++ b/src/librustc/infer/canonical/query_response.rs
@@ -7,26 +7,26 @@
 //!
 //! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
 
-use infer::canonical::substitute::substitute_value;
-use infer::canonical::{
+use crate::infer::canonical::substitute::substitute_value;
+use crate::infer::canonical::{
     Canonical, CanonicalVarValues, CanonicalizedQueryResponse, Certainty,
     OriginalQueryValues, QueryRegionConstraint, QueryResponse,
 };
-use infer::region_constraints::{Constraint, RegionConstraintData};
-use infer::InferCtxtBuilder;
-use infer::{InferCtxt, InferOk, InferResult};
+use crate::infer::region_constraints::{Constraint, RegionConstraintData};
+use crate::infer::InferCtxtBuilder;
+use crate::infer::{InferCtxt, InferOk, InferResult};
 use rustc_data_structures::indexed_vec::Idx;
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::sync::Lrc;
 use std::fmt::Debug;
 use syntax_pos::DUMMY_SP;
-use traits::query::{Fallible, NoSolution};
-use traits::TraitEngine;
-use traits::{Obligation, ObligationCause, PredicateObligation};
-use ty::fold::TypeFoldable;
-use ty::subst::{Kind, UnpackedKind};
-use ty::{self, BoundVar, Lift, Ty, TyCtxt};
-use util::captures::Captures;
+use crate::traits::query::{Fallible, NoSolution};
+use crate::traits::TraitEngine;
+use crate::traits::{Obligation, ObligationCause, PredicateObligation};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::subst::{Kind, UnpackedKind};
+use crate::ty::{self, BoundVar, Lift, Ty, TyCtxt};
+use crate::util::captures::Captures;
 
 impl<'cx, 'gcx, 'tcx> InferCtxtBuilder<'cx, 'gcx, 'tcx> {
     /// The "main method" for a canonicalized trait query. Given the
@@ -119,7 +119,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// If you DO want to keep track of pending obligations (which
     /// include all region obligations, so this includes all cases
     /// that care about regions) with this function, you have to
-    /// do it yourself, by e.g. having them be a part of the answer.
+    /// do it yourself, by e.g., having them be a part of the answer.
     pub fn make_query_response_ignoring_pending_obligations<T>(
         &self,
         inference_vars: CanonicalVarValues<'tcx>,
@@ -267,7 +267,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     ///   they should be ignored).
     /// - It **can happen** (though it rarely does currently) that
     ///   equating types and things will give rise to subobligations
-    ///   that must be processed.  In this case, those subobligations
+    ///   that must be processed. In this case, those subobligations
     ///   are propagated back in the return value.
     /// - Finally, the query result (of type `R`) is propagated back,
     ///   after applying the substitution `S`.
@@ -506,7 +506,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 
     /// Given a "guess" at the values for the canonical variables in
     /// the input, try to unify with the *actual* values found in the
-    /// query result.  Often, but not always, this is a no-op, because
+    /// query result. Often, but not always, this is a no-op, because
     /// we already found the mapping in the "guessing" step.
     ///
     /// See also: `query_response_substitution_guess`
diff --git a/src/librustc/infer/canonical/substitute.rs b/src/librustc/infer/canonical/substitute.rs
index d3ed00481dcee..5af4e8366818b 100644
--- a/src/librustc/infer/canonical/substitute.rs
+++ b/src/librustc/infer/canonical/substitute.rs
@@ -6,10 +6,10 @@
 //!
 //! [c]: https://rust-lang.github.io/rustc-guide/traits/canonicalization.html
 
-use infer::canonical::{Canonical, CanonicalVarValues};
-use ty::fold::TypeFoldable;
-use ty::subst::UnpackedKind;
-use ty::{self, TyCtxt};
+use crate::infer::canonical::{Canonical, CanonicalVarValues};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::subst::UnpackedKind;
+use crate::ty::{self, TyCtxt};
 
 impl<'tcx, V> Canonical<'tcx, V> {
     /// Instantiate the wrapped value, replacing each canonical value
diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index 40c11695d51e2..9cd5a844f1590 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -29,13 +29,13 @@ use super::lub::Lub;
 use super::sub::Sub;
 use super::type_variable::TypeVariableValue;
 
-use hir::def_id::DefId;
-use ty::{IntType, UintType};
-use ty::{self, Ty, TyCtxt};
-use ty::error::TypeError;
-use ty::relate::{self, Relate, RelateResult, TypeRelation};
-use ty::subst::Substs;
-use traits::{Obligation, PredicateObligations};
+use crate::hir::def_id::DefId;
+use crate::ty::{IntType, UintType};
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::error::TypeError;
+use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
+use crate::ty::subst::Substs;
+use crate::traits::{Obligation, PredicateObligations};
 
 use syntax::ast;
 use syntax_pos::Span;
@@ -165,8 +165,8 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
         Glb::new(self, a_is_expected)
     }
 
-    /// Here dir is either EqTo, SubtypeOf, or SupertypeOf. The
-    /// idea is that we should ensure that the type `a_ty` is equal
+    /// Here, `dir` is either `EqTo`, `SubtypeOf`, or `SupertypeOf`.
+    /// The idea is that we should ensure that the type `a_ty` is equal
     /// to, a subtype of, or a supertype of (respectively) the type
     /// to which `b_vid` is bound.
     ///
@@ -255,10 +255,24 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
             RelationDir::SupertypeOf => ty::Contravariant,
         };
 
+        debug!("generalize: ambient_variance = {:?}", ambient_variance);
+
+        let for_universe = match self.infcx.type_variables.borrow_mut().probe(for_vid) {
+            v @ TypeVariableValue::Known { .. } => panic!(
+                "instantiating {:?} which has a known value {:?}",
+                for_vid,
+                v,
+            ),
+            TypeVariableValue::Unknown { universe } => universe,
+        };
+
+        debug!("generalize: for_universe = {:?}", for_universe);
+
         let mut generalize = Generalizer {
             infcx: self.infcx,
             span: self.trace.cause.span,
             for_vid_sub_root: self.infcx.type_variables.borrow_mut().sub_root_var(for_vid),
+            for_universe,
             ambient_variance,
             needs_wf: false,
             root_ty: ty,
@@ -280,7 +294,7 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
 struct Generalizer<'cx, 'gcx: 'cx+'tcx, 'tcx: 'cx> {
     infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
 
-    /// Span, used when creating new type variables and things.
+    /// The span, used when creating new type variables and things.
     span: Span,
 
     /// The vid of the type variable that is in the process of being
@@ -288,6 +302,11 @@ struct Generalizer<'cx, 'gcx: 'cx+'tcx, 'tcx: 'cx> {
     /// that means we would have created a cyclic type.
     for_vid_sub_root: ty::TyVid,
 
+    /// The universe of the type variable that is in the process of
+    /// being instantiated. Any fresh variables that we create in this
+    /// process should be in that same universe.
+    for_universe: ty::UniverseIndex,
+
     /// Track the variance as we descend into the type.
     ambient_variance: ty::Variance,
 
@@ -310,7 +329,7 @@ struct Generalization<'tcx> {
     /// particular around 'bivariant' type parameters that are only
     /// constrained by a where-clause. As an example, imagine a type:
     ///
-    ///     struct Foo<A, B> where A: Iterator<Item=B> {
+    ///     struct Foo<A, B> where A: Iterator<Item = B> {
     ///         data: A
     ///     }
     ///
@@ -323,7 +342,7 @@ struct Generalization<'tcx> {
     /// <: ?C`, but no particular relationship between `?B` and `?D`
     /// (after all, we do not know the variance of the normalized form
     /// of `A::Item` with respect to `A`). If we do nothing else, this
-    /// may mean that `?D` goes unconstrained (as in #41677).  So, in
+    /// may mean that `?D` goes unconstrained (as in #41677). So, in
     /// this scenario where we create a new type variable in a
     /// bivariant context, we set the `needs_wf` flag to true. This
     /// will force the calling code to check that `WF(Foo<?C, ?D>)`
@@ -386,6 +405,8 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
     fn tys(&mut self, t: Ty<'tcx>, t2: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
         assert_eq!(t, t2); // we are abusing TypeRelation here; both LHS and RHS ought to be ==
 
+        debug!("generalize: t={:?}", t);
+
         // Check to see whether the type we are genealizing references
         // any other type variable related to `vid` via
         // subtyping. This is basically our "occurs check", preventing
@@ -403,12 +424,17 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
                     match variables.probe(vid) {
                         TypeVariableValue::Known { value: u } => {
                             drop(variables);
+                            debug!("generalize: known value {:?}", u);
                             self.relate(&u, &u)
                         }
                         TypeVariableValue::Unknown { universe } => {
                             match self.ambient_variance {
                                 // Invariant: no need to make a fresh type variable.
-                                ty::Invariant => return Ok(t),
+                                ty::Invariant => {
+                                    if self.for_universe.can_name(universe) {
+                                        return Ok(t);
+                                    }
+                                }
 
                                 // Bivariant: make a fresh var, but we
                                 // may need a WF predicate. See
@@ -422,7 +448,7 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
                             }
 
                             let origin = *variables.var_origin(vid);
-                            let new_var_id = variables.new_var(universe, false, origin);
+                            let new_var_id = variables.new_var(self.for_universe, false, origin);
                             let u = self.tcx().mk_var(new_var_id);
                             debug!("generalize: replacing original vid={:?} with new={:?}",
                                    vid, u);
@@ -448,6 +474,8 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
                -> RelateResult<'tcx, ty::Region<'tcx>> {
         assert_eq!(r, r2); // we are abusing TypeRelation here; both LHS and RHS ought to be ==
 
+        debug!("generalize: regions r={:?}", r);
+
         match *r {
             // Never make variables for regions bound within the type itself,
             // nor for erased regions.
@@ -456,37 +484,40 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
                 return Ok(r);
             }
 
-            // Always make a fresh region variable for placeholder
-            // regions; the higher-ranked decision procedures rely on
-            // this.
-            ty::RePlaceholder(..) => { }
+            ty::ReClosureBound(..) => {
+                span_bug!(
+                    self.span,
+                    "encountered unexpected ReClosureBound: {:?}",
+                    r,
+                );
+            }
 
-            // For anything else, we make a region variable, unless we
-            // are *equating*, in which case it's just wasteful.
+            ty::RePlaceholder(..) |
+            ty::ReVar(..) |
             ty::ReEmpty |
             ty::ReStatic |
             ty::ReScope(..) |
-            ty::ReVar(..) |
             ty::ReEarlyBound(..) |
             ty::ReFree(..) => {
-                match self.ambient_variance {
-                    ty::Invariant => return Ok(r),
-                    ty::Bivariant | ty::Covariant | ty::Contravariant => (),
-                }
+                // see common code below
             }
+        }
 
-            ty::ReClosureBound(..) => {
-                span_bug!(
-                    self.span,
-                    "encountered unexpected ReClosureBound: {:?}",
-                    r,
-                );
+        // If we are in an invariant context, we can re-use the region
+        // as is, unless it happens to be in some universe that we
+        // can't name. (In the case of a region *variable*, we could
+        // use it if we promoted it into our universe, but we don't
+        // bother.)
+        if let ty::Invariant = self.ambient_variance {
+            let r_universe = self.infcx.universe_of_region(r);
+            if self.for_universe.can_name(r_universe) {
+                return Ok(r);
             }
         }
 
         // FIXME: This is non-ideal because we don't give a
         // very descriptive origin for this region variable.
-        Ok(self.infcx.next_region_var(MiscVariable(self.span)))
+        Ok(self.infcx.next_region_var_in_universe(MiscVariable(self.span), self.for_universe))
     }
 }
 
diff --git a/src/librustc/infer/equate.rs b/src/librustc/infer/equate.rs
index 60a7eb0d54f8b..a4b62307a60b8 100644
--- a/src/librustc/infer/equate.rs
+++ b/src/librustc/infer/equate.rs
@@ -1,12 +1,12 @@
 use super::combine::{CombineFields, RelationDir};
 use super::{Subtype};
 
-use hir::def_id::DefId;
+use crate::hir::def_id::DefId;
 
-use ty::{self, Ty, TyCtxt};
-use ty::TyVar;
-use ty::subst::Substs;
-use ty::relate::{self, Relate, RelateResult, TypeRelation};
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::TyVar;
+use crate::ty::subst::Substs;
+use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
 
 /// Ensures `a` is made equal to `b`. Returns `a` on success.
 pub struct Equate<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
diff --git a/src/librustc/infer/error_reporting/mod.rs b/src/librustc/infer/error_reporting/mod.rs
index 2995b25308d4c..705d9c4cf93ea 100644
--- a/src/librustc/infer/error_reporting/mod.rs
+++ b/src/librustc/infer/error_reporting/mod.rs
@@ -48,19 +48,18 @@
 use super::lexical_region_resolve::RegionResolutionError;
 use super::region_constraints::GenericKind;
 use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePairs};
-use infer::{self, SuppressRegionErrors};
-
+use crate::infer::{self, SuppressRegionErrors};
+
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::hir::Node;
+use crate::middle::region;
+use crate::traits::{ObligationCause, ObligationCauseCode};
+use crate::ty::error::TypeError;
+use crate::ty::{self, subst::Subst, Region, Ty, TyCtxt, TyKind, TypeFoldable};
 use errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
-use hir;
-use hir::def_id::DefId;
-use hir::Node;
-use middle::region;
 use std::{cmp, fmt};
-use syntax::ast::DUMMY_NODE_ID;
 use syntax_pos::{Pos, Span};
-use traits::{ObligationCause, ObligationCauseCode};
-use ty::error::TypeError;
-use ty::{self, subst::Subst, Region, Ty, TyCtxt, TyKind, TypeFoldable};
 
 mod note;
 
@@ -182,8 +181,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         let cm = self.sess.source_map();
 
         let scope = region.free_region_binding_scope(self);
-        let node = self.hir().as_local_node_id(scope).unwrap_or(DUMMY_NODE_ID);
-        let tag = match self.hir().find(node) {
+        let node = self.hir().as_local_hir_id(scope).unwrap_or(hir::DUMMY_HIR_ID);
+        let tag = match self.hir().find_by_hir_id(node) {
             Some(Node::Block(_)) | Some(Node::Expr(_)) => "body",
             Some(Node::Item(it)) => Self::item_scope_tag(&it),
             Some(Node::TraitItem(it)) => Self::trait_item_scope_tag(&it),
@@ -192,7 +191,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         };
         let (prefix, span) = match *region {
             ty::ReEarlyBound(ref br) => {
-                let mut sp = cm.def_span(self.hir().span(node));
+                let mut sp = cm.def_span(self.hir().span_by_hir_id(node));
                 if let Some(param) = self.hir()
                     .get_generics(scope)
                     .and_then(|generics| generics.get_named(&br.name))
@@ -205,7 +204,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 bound_region: ty::BoundRegion::BrNamed(_, ref name),
                 ..
             }) => {
-                let mut sp = cm.def_span(self.hir().span(node));
+                let mut sp = cm.def_span(self.hir().span_by_hir_id(node));
                 if let Some(param) = self.hir()
                     .get_generics(scope)
                     .and_then(|generics| generics.get_named(&name))
@@ -217,15 +216,15 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             ty::ReFree(ref fr) => match fr.bound_region {
                 ty::BrAnon(idx) => (
                     format!("the anonymous lifetime #{} defined on", idx + 1),
-                    self.hir().span(node),
+                    self.hir().span_by_hir_id(node),
                 ),
                 ty::BrFresh(_) => (
                     "an anonymous lifetime defined on".to_owned(),
-                    self.hir().span(node),
+                    self.hir().span_by_hir_id(node),
                 ),
                 _ => (
                     format!("the lifetime {} as defined on", fr.bound_region),
-                    cm.def_span(self.hir().span(node)),
+                    cm.def_span(self.hir().span_by_hir_id(node)),
                 ),
             },
             _ => bug!(),
@@ -485,29 +484,55 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    fn note_error_origin(&self, err: &mut DiagnosticBuilder<'tcx>, cause: &ObligationCause<'tcx>) {
+    fn note_error_origin(
+        &self,
+        err: &mut DiagnosticBuilder<'tcx>,
+        cause: &ObligationCause<'tcx>,
+        exp_found: Option<ty::error::ExpectedFound<Ty<'tcx>>>,
+    ) {
         match cause.code {
             ObligationCauseCode::MatchExpressionArmPattern { span, ty } => {
                 if ty.is_suggestable() {  // don't show type `_`
                     err.span_label(span, format!("this match expression has type `{}`", ty));
                 }
+                if let Some(ty::error::ExpectedFound { found, .. }) = exp_found {
+                    if ty.is_box() && ty.boxed_ty() == found {
+                        if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span) {
+                            err.span_suggestion(
+                                span,
+                                "consider dereferencing the boxed value",
+                                format!("*{}", snippet),
+                                Applicability::MachineApplicable,
+                            );
+                        }
+                    }
+                }
             }
-            ObligationCauseCode::MatchExpressionArm { arm_span, source } => match source {
+            ObligationCauseCode::MatchExpressionArm {
+                source,
+                ref prior_arms,
+                last_ty,
+                ..
+            } => match source {
                 hir::MatchSource::IfLetDesugar { .. } => {
-                    let msg = "`if let` arm with an incompatible type";
-                    if self.tcx.sess.source_map().is_multiline(arm_span) {
-                        err.span_note(arm_span, msg);
-                    } else {
-                        err.span_label(arm_span, msg);
-                    }
+                    let msg = "`if let` arms have incompatible types";
+                    err.span_label(cause.span, msg);
                 }
                 hir::MatchSource::TryDesugar => {}
                 _ => {
-                    let msg = "match arm with an incompatible type";
-                    if self.tcx.sess.source_map().is_multiline(arm_span) {
-                        err.span_note(arm_span, msg);
-                    } else {
-                        err.span_label(arm_span, msg);
+                    let msg = "`match` arms have incompatible types";
+                    err.span_label(cause.span, msg);
+                    if prior_arms.len() <= 4 {
+                        for sp in prior_arms {
+                            err.span_label(*sp, format!(
+                                "this is found to be of type `{}`",
+                                last_ty,
+                            ));
+                        }
+                    } else if let Some(sp) = prior_arms.last() {
+                        err.span_label(*sp, format!(
+                            "this and all prior arms are found to be of type `{}`", last_ty,
+                        ));
                     }
                 }
             },
@@ -515,7 +540,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 err.span_label(then, "expected because of this");
                 outer.map(|sp| err.span_label(sp, "if and else have incompatible types"));
                 if let Some(sp) = semicolon {
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         sp,
                         "consider removing this semicolon",
                         String::new(),
@@ -643,7 +668,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         None
     }
 
-    /// Add a `,` to the type representation only if it is appropriate.
+    /// Adds a `,` to the type representation only if it is appropriate.
     fn push_comma(
         &self,
         value: &mut DiagnosticStyledString,
@@ -699,7 +724,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         substs.truncate_to(self.tcx, &generics)
     }
 
-    /// Compare two given types, eliding parts that are the same between them and highlighting
+    /// Compares two given types, eliding parts that are the same between them and highlighting
     /// relevant differences, and return two representation of those types for highlighted printing.
     fn cmp(&self, t1: Ty<'tcx>, t2: Ty<'tcx>) -> (DiagnosticStyledString, DiagnosticStyledString) {
         fn equals<'tcx>(a: &Ty<'tcx>, b: &Ty<'tcx>) -> bool {
@@ -1013,7 +1038,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
 
         // It reads better to have the error origin as the final
         // thing.
-        self.note_error_origin(diag, &cause);
+        self.note_error_origin(diag, &cause, exp_found);
     }
 
     /// When encountering a case where `.as_ref()` on a `Result` or `Option` would be appropriate,
@@ -1067,7 +1092,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                                 self.tcx.sess.source_map().span_to_snippet(span),
                                 show_suggestion,
                             ) {
-                                diag.span_suggestion_with_applicability(
+                                diag.span_suggestion(
                                     span,
                                     msg,
                                     format!("{}.as_ref()", snippet),
@@ -1256,7 +1281,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                     let tail = if has_lifetimes { " + " } else { "" };
                     format!("{}: {}{}", bound_kind, sub, tail)
                 };
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     sp,
                     &consider,
                     suggestion,
@@ -1434,8 +1459,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 format!(" for lifetime parameter `{}` in coherence check", name)
             }
             infer::UpvarRegion(ref upvar_id, _) => {
-                let var_node_id = self.tcx.hir().hir_to_node_id(upvar_id.var_path.hir_id);
-                let var_name = self.tcx.hir().name(var_node_id);
+                let var_name = self.tcx.hir().name_by_hir_id(upvar_id.var_path.hir_id);
                 format!(" for capture of `{}` by closure", var_name)
             }
             infer::NLL(..) => bug!("NLL variable found in lexical phase"),
@@ -1462,7 +1486,7 @@ enum FailureCode {
 impl<'tcx> ObligationCause<'tcx> {
     fn as_failure_code(&self, terr: &TypeError<'tcx>) -> FailureCode {
         use self::FailureCode::*;
-        use traits::ObligationCauseCode::*;
+        use crate::traits::ObligationCauseCode::*;
         match self.code {
             CompareImplMethodObligation { .. } => Error0308("method not compatible with trait"),
             MatchExpressionArm { source, .. } => Error0308(match source {
@@ -1492,7 +1516,7 @@ impl<'tcx> ObligationCause<'tcx> {
     }
 
     fn as_requirement_str(&self) -> &'static str {
-        use traits::ObligationCauseCode::*;
+        use crate::traits::ObligationCauseCode::*;
         match self.code {
             CompareImplMethodObligation { .. } => "method type is compatible with trait",
             ExprAssignable => "expression is assignable",
diff --git a/src/librustc/infer/error_reporting/need_type_info.rs b/src/librustc/infer/error_reporting/need_type_info.rs
index 8ee367c87c3ea..9e0e48e474118 100644
--- a/src/librustc/infer/error_reporting/need_type_info.rs
+++ b/src/librustc/infer/error_reporting/need_type_info.rs
@@ -1,8 +1,8 @@
-use hir::{self, Local, Pat, Body, HirId};
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
-use infer::InferCtxt;
-use infer::type_variable::TypeVariableOrigin;
-use ty::{self, Ty, Infer, TyVar};
+use crate::hir::{self, Local, Pat, Body, HirId};
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::infer::InferCtxt;
+use crate::infer::type_variable::TypeVariableOrigin;
+use crate::ty::{self, Ty, Infer, TyVar};
 use syntax::source_map::CompilerDesugaringKind;
 use syntax_pos::Span;
 use errors::DiagnosticBuilder;
@@ -16,9 +16,9 @@ struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
 }
 
 impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
-    fn node_matches_type(&mut self, node_id: HirId) -> bool {
+    fn node_matches_type(&mut self, hir_id: HirId) -> bool {
         let ty_opt = self.infcx.in_progress_tables.and_then(|tables| {
-            tables.borrow().node_id_to_type_opt(node_id)
+            tables.borrow().node_type_opt(hir_id)
         });
         match ty_opt {
             Some(ty) => {
@@ -105,7 +105,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         };
 
         if let Some(body_id) = body_id {
-            let expr = self.tcx.hir().expect_expr(body_id.node_id);
+            let expr = self.tcx.hir().expect_expr_by_hir_id(body_id.hir_id);
             local_visitor.visit_expr(expr);
         }
 
diff --git a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
index bfb5b61d0aa1f..5d5a9b36087a2 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/different_lifetimes.rs
@@ -1,9 +1,9 @@
 //! Error Reporting for Anonymous Region Lifetime Errors
 //! where both the regions are anonymous.
 
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use infer::error_reporting::nice_region_error::util::AnonymousArgInfo;
-use util::common::ErrorReported;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::error_reporting::nice_region_error::util::AnonymousArgInfo;
+use crate::util::common::ErrorReported;
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     /// Print the error message for lifetime errors when both the concerned regions are anonymous.
@@ -39,16 +39,16 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     ///     x.push(y);
     ///     ^ ...but data from `y` flows into `x` here
     /// }
-    /// ````
+    /// ```
     ///
     /// It will later be extended to trait objects.
     pub(super) fn try_report_anon_anon_conflict(&self) -> Option<ErrorReported> {
         let (span, sub, sup) = self.get_regions();
 
         // Determine whether the sub and sup consist of both anonymous (elided) regions.
-        let anon_reg_sup = self.tcx.is_suitable_region(sup)?;
+        let anon_reg_sup = self.tcx().is_suitable_region(sup)?;
 
-        let anon_reg_sub = self.tcx.is_suitable_region(sub)?;
+        let anon_reg_sub = self.tcx().is_suitable_region(sub)?;
         let scope_def_id_sup = anon_reg_sup.def_id;
         let bregion_sup = anon_reg_sup.boundregion;
         let scope_def_id_sub = anon_reg_sub.def_id;
@@ -138,7 +138,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         };
 
 
-        struct_span_err!(self.tcx.sess, span, E0623, "lifetime mismatch")
+        struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch")
             .span_label(span_1, main_label)
             .span_label(span_2, String::new())
             .span_label(span, span_label)
diff --git a/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs b/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
index d230ce55471e9..ea748874fc4e2 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/find_anon_type.rs
@@ -1,9 +1,9 @@
-use hir;
-use ty::{self, Region, TyCtxt};
-use hir::Node;
-use middle::resolve_lifetime as rl;
-use hir::intravisit::{self, NestedVisitorMap, Visitor};
-use infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::hir;
+use crate::ty::{self, Region, TyCtxt};
+use crate::hir::Node;
+use crate::middle::resolve_lifetime as rl;
+use crate::hir::intravisit::{self, NestedVisitorMap, Visitor};
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     /// This function calls the `visit_ty` method for the parameters
@@ -26,10 +26,10 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         region: Region<'tcx>,
         br: &ty::BoundRegion,
     ) -> Option<(&hir::Ty, &hir::FnDecl)> {
-        if let Some(anon_reg) = self.tcx.is_suitable_region(region) {
+        if let Some(anon_reg) = self.tcx().is_suitable_region(region) {
             let def_id = anon_reg.def_id;
-            if let Some(node_id) = self.tcx.hir().as_local_node_id(def_id) {
-                let fndecl = match self.tcx.hir().get(node_id) {
+            if let Some(node_id) = self.tcx().hir().as_local_node_id(def_id) {
+                let fndecl = match self.tcx().hir().get(node_id) {
                     Node::Item(&hir::Item {
                         node: hir::ItemKind::Fn(ref fndecl, ..),
                         ..
@@ -64,7 +64,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         br: &ty::BoundRegion,
     ) -> Option<(&'gcx hir::Ty)> {
         let mut nested_visitor = FindNestedTypeVisitor {
-            tcx: self.tcx,
+            tcx: self.tcx(),
             bound_region: *br,
             found_type: None,
             current_index: ty::INNERMOST,
@@ -114,7 +114,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for FindNestedTypeVisitor<'a, 'gcx, 'tcx> {
 
             hir::TyKind::Rptr(ref lifetime, _) => {
                 // the lifetime of the TyRptr
-                let hir_id = self.tcx.hir().node_to_hir_id(lifetime.id);
+                let hir_id = lifetime.hir_id;
                 match (self.tcx.named_region(hir_id), self.bound_region) {
                     // Find the index of the anonymous region that was part of the
                     // error. We will then search the function parameters for a bound
@@ -221,8 +221,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for TyPathVisitor<'a, 'gcx, 'tcx> {
     }
 
     fn visit_lifetime(&mut self, lifetime: &hir::Lifetime) {
-        let hir_id = self.tcx.hir().node_to_hir_id(lifetime.id);
-        match (self.tcx.named_region(hir_id), self.bound_region) {
+        match (self.tcx.named_region(lifetime.hir_id), self.bound_region) {
             // the lifetime of the TyPath!
             (Some(rl::Region::LateBoundAnon(debruijn_index, anon_index)), ty::BrAnon(br_index)) => {
                 if debruijn_index == self.current_index && anon_index == br_index {
diff --git a/src/librustc/infer/error_reporting/nice_region_error/mod.rs b/src/librustc/infer/error_reporting/nice_region_error/mod.rs
index f7ba546fa7f3b..d995fe92337c4 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/mod.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/mod.rs
@@ -1,9 +1,10 @@
-use infer::InferCtxt;
-use infer::lexical_region_resolve::RegionResolutionError;
-use infer::lexical_region_resolve::RegionResolutionError::*;
+use crate::infer::InferCtxt;
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError::*;
+use crate::ty::{self, TyCtxt};
+use crate::util::common::ErrorReported;
+use errors::DiagnosticBuilder;
 use syntax::source_map::Span;
-use ty::{self, TyCtxt};
-use util::common::ErrorReported;
 
 mod different_lifetimes;
 mod find_anon_type;
@@ -22,15 +23,15 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
 
         if let Some(tables) = self.in_progress_tables {
             let tables = tables.borrow();
-            NiceRegionError::new(self.tcx, error.clone(), Some(&tables)).try_report().is_some()
+            NiceRegionError::new(self, error.clone(), Some(&tables)).try_report().is_some()
         } else {
-            NiceRegionError::new(self.tcx, error.clone(), None).try_report().is_some()
+            NiceRegionError::new(self, error.clone(), None).try_report().is_some()
         }
     }
 }
 
 pub struct NiceRegionError<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
-    tcx: TyCtxt<'cx, 'gcx, 'tcx>,
+    infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
     error: Option<RegionResolutionError<'tcx>>,
     regions: Option<(Span, ty::Region<'tcx>, ty::Region<'tcx>)>,
     tables: Option<&'cx ty::TypeckTables<'tcx>>,
@@ -38,24 +39,28 @@ pub struct NiceRegionError<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
 
 impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
     pub fn new(
-        tcx: TyCtxt<'cx, 'gcx, 'tcx>,
+        infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
         error: RegionResolutionError<'tcx>,
         tables: Option<&'cx ty::TypeckTables<'tcx>>,
     ) -> Self {
-        Self { tcx, error: Some(error), regions: None, tables }
+        Self { infcx, error: Some(error), regions: None, tables }
     }
 
     pub fn new_from_span(
-        tcx: TyCtxt<'cx, 'gcx, 'tcx>,
+        infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
         span: Span,
         sub: ty::Region<'tcx>,
         sup: ty::Region<'tcx>,
         tables: Option<&'cx ty::TypeckTables<'tcx>>,
     ) -> Self {
-        Self { tcx, error: None, regions: Some((span, sub, sup)), tables }
+        Self { infcx, error: None, regions: Some((span, sub, sup)), tables }
     }
 
-    pub fn try_report_from_nll(&self) -> Option<ErrorReported> {
+    fn tcx(&self) -> TyCtxt<'cx, 'gcx, 'tcx> {
+        self.infcx.tcx
+    }
+
+    pub fn try_report_from_nll(&self) -> Option<DiagnosticBuilder<'cx>> {
         // Due to the improved diagnostics returned by the MIR borrow checker, only a subset of
         // the nice region errors are required when running under the MIR borrow checker.
         self.try_report_named_anon_conflict()
@@ -64,6 +69,7 @@ impl<'cx, 'gcx, 'tcx> NiceRegionError<'cx, 'gcx, 'tcx> {
 
     pub fn try_report(&self) -> Option<ErrorReported> {
         self.try_report_from_nll()
+            .map(|mut diag| { diag.emit(); ErrorReported })
             .or_else(|| self.try_report_anon_anon_conflict())
             .or_else(|| self.try_report_outlives_closure())
             .or_else(|| self.try_report_static_impl_trait())
diff --git a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
index daab0a8e96263..3821484d38e5f 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/named_anon_conflict.rs
@@ -1,14 +1,13 @@
 //! Error Reporting for Anonymous Region Lifetime Errors
 //! where one region is named and the other is anonymous.
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use ty;
-use util::common::ErrorReported;
-use errors::Applicability;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::ty;
+use errors::{Applicability, DiagnosticBuilder};
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
     /// an anonymous region, emit an descriptive diagnostic error.
-    pub(super) fn try_report_named_anon_conflict(&self) -> Option<ErrorReported> {
+    pub(super) fn try_report_named_anon_conflict(&self) -> Option<DiagnosticBuilder<'a>> {
         let (span, sub, sup) = self.get_regions();
 
         debug!(
@@ -24,23 +23,23 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         // version new_ty of its type where the anonymous region is replaced
         // with the named one.//scope_def_id
         let (named, anon, anon_arg_info, region_info) = if self.is_named_region(sub)
-            && self.tcx.is_suitable_region(sup).is_some()
+            && self.tcx().is_suitable_region(sup).is_some()
             && self.find_arg_with_region(sup, sub).is_some()
         {
             (
                 sub,
                 sup,
                 self.find_arg_with_region(sup, sub).unwrap(),
-                self.tcx.is_suitable_region(sup).unwrap(),
+                self.tcx().is_suitable_region(sup).unwrap(),
             )
-        } else if self.is_named_region(sup) && self.tcx.is_suitable_region(sub).is_some()
+        } else if self.is_named_region(sup) && self.tcx().is_suitable_region(sub).is_some()
             && self.find_arg_with_region(sub, sup).is_some()
         {
             (
                 sup,
                 sub,
                 self.find_arg_with_region(sub, sup).unwrap(),
-                self.tcx.is_suitable_region(sub).unwrap(),
+                self.tcx().is_suitable_region(sub).unwrap(),
             )
         } else {
             return None; // inapplicable
@@ -96,21 +95,23 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             ("parameter type".to_owned(), "type".to_owned())
         };
 
-        struct_span_err!(
-            self.tcx.sess,
+        let mut diag = struct_span_err!(
+            self.tcx().sess,
             span,
             E0621,
             "explicit lifetime required in {}",
             error_var
-        ).span_suggestion_with_applicability(
-            new_ty_span,
-            &format!("add explicit lifetime `{}` to {}", named, span_label_var),
-            new_ty.to_string(),
-            Applicability::Unspecified,
-        )
-        .span_label(span, format!("lifetime `{}` required", named))
-        .emit();
-        return Some(ErrorReported);
+        );
+
+        diag.span_suggestion(
+                new_ty_span,
+                &format!("add explicit lifetime `{}` to {}", named, span_label_var),
+                new_ty.to_string(),
+                Applicability::Unspecified,
+            )
+            .span_label(span, format!("lifetime `{}` required", named));
+
+        Some(diag)
     }
 
     // This method returns whether the given Region is Named
diff --git a/src/librustc/infer/error_reporting/nice_region_error/outlives_closure.rs b/src/librustc/infer/error_reporting/nice_region_error/outlives_closure.rs
index c4c71037d8b35..6432780de0670 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/outlives_closure.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/outlives_closure.rs
@@ -1,13 +1,13 @@
 //! Error Reporting for Anonymous Region Lifetime Errors
 //! where both the regions are anonymous.
 
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use infer::SubregionOrigin;
-use ty::RegionKind;
-use hir::{Expr, ExprKind::Closure};
-use hir::Node;
-use util::common::ErrorReported;
-use infer::lexical_region_resolve::RegionResolutionError::SubSupConflict;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::SubregionOrigin;
+use crate::ty::RegionKind;
+use crate::hir::{Expr, ExprKind::Closure};
+use crate::hir::Node;
+use crate::util::common::ErrorReported;
+use crate::infer::lexical_region_resolve::RegionResolutionError::SubSupConflict;
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     /// Print the error message for lifetime errors when binding escapes a closure.
@@ -47,7 +47,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
             // closure, provide a specific message pointing this out.
             if let (&SubregionOrigin::BindingTypeIsNotValidAtDecl(ref external_span),
                     &RegionKind::ReFree(ref free_region)) = (&sub_origin, sup_region) {
-                let hir = &self.tcx.hir();
+                let hir = &self.tcx().hir();
                 if let Some(node_id) = hir.as_local_node_id(free_region.scope) {
                     if let Node::Expr(Expr {
                         node: Closure(_, _, _, closure_span, None),
@@ -55,7 +55,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                     }) = hir.get(node_id) {
                         let sup_sp = sup_origin.span();
                         let origin_sp = origin.span();
-                        let mut err = self.tcx.sess.struct_span_err(
+                        let mut err = self.tcx().sess.struct_span_err(
                             sup_sp,
                             "borrowed data cannot be stored outside of its closure");
                         err.span_label(sup_sp, "cannot be stored outside of its closure");
diff --git a/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs b/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
index 0dda636a9bd53..3b2fb7d41008e 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/placeholder_error.rs
@@ -1,19 +1,19 @@
-use hir::def_id::DefId;
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use infer::lexical_region_resolve::RegionResolutionError;
-use infer::ValuePairs;
-use infer::{SubregionOrigin, TypeTrace};
-use traits::{ObligationCause, ObligationCauseCode};
-use ty;
-use ty::error::ExpectedFound;
-use ty::subst::Substs;
-use util::common::ErrorReported;
-use util::ppaux::RegionHighlightMode;
+use errors::DiagnosticBuilder;
+use crate::hir::def_id::DefId;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::infer::ValuePairs;
+use crate::infer::{SubregionOrigin, TypeTrace};
+use crate::traits::{ObligationCause, ObligationCauseCode};
+use crate::ty;
+use crate::ty::error::ExpectedFound;
+use crate::ty::subst::Substs;
+use crate::util::ppaux::RegionHighlightMode;
 
 impl NiceRegionError<'me, 'gcx, 'tcx> {
     /// When given a `ConcreteFailure` for a function with arguments containing a named region and
-    /// an anonymous region, emit an descriptive diagnostic error.
-    pub(super) fn try_report_placeholder_conflict(&self) -> Option<ErrorReported> {
+    /// an anonymous region, emit a descriptive diagnostic error.
+    pub(super) fn try_report_placeholder_conflict(&self) -> Option<DiagnosticBuilder<'me>> {
         match &self.error {
             ///////////////////////////////////////////////////////////////////////////
             // NB. The ordering of cases in this match is very
@@ -34,19 +34,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 sub_placeholder @ ty::RePlaceholder(_),
                 _,
                 sup_placeholder @ ty::RePlaceholder(_),
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    Some(self.tcx.mk_region(ty::ReVar(*vid))),
-                    cause,
-                    Some(sub_placeholder),
-                    Some(sup_placeholder),
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(self.tcx().mk_region(ty::ReVar(*vid))),
+                cause,
+                Some(sub_placeholder),
+                Some(sup_placeholder),
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             Some(RegionResolutionError::SubSupConflict(
                 vid,
@@ -58,19 +54,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 sub_placeholder @ ty::RePlaceholder(_),
                 _,
                 _,
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    Some(self.tcx.mk_region(ty::ReVar(*vid))),
-                    cause,
-                    Some(sub_placeholder),
-                    None,
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(self.tcx().mk_region(ty::ReVar(*vid))),
+                cause,
+                Some(sub_placeholder),
+                None,
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             Some(RegionResolutionError::SubSupConflict(
                 vid,
@@ -82,19 +74,35 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 _,
                 _,
                 sup_placeholder @ ty::RePlaceholder(_),
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    Some(self.tcx.mk_region(ty::ReVar(*vid))),
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(self.tcx().mk_region(ty::ReVar(*vid))),
+                cause,
+                None,
+                Some(*sup_placeholder),
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
+
+            Some(RegionResolutionError::SubSupConflict(
+                vid,
+                _,
+                _,
+                _,
+                SubregionOrigin::Subtype(TypeTrace {
                     cause,
-                    None,
-                    Some(*sup_placeholder),
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+                    values: ValuePairs::TraitRefs(ExpectedFound { expected, found }),
+                }),
+                sup_placeholder @ ty::RePlaceholder(_),
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(self.tcx().mk_region(ty::ReVar(*vid))),
+                cause,
+                None,
+                Some(*sup_placeholder),
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             Some(RegionResolutionError::ConcreteFailure(
                 SubregionOrigin::Subtype(TypeTrace {
@@ -103,19 +111,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 }),
                 sub_region @ ty::RePlaceholder(_),
                 sup_region @ ty::RePlaceholder(_),
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    None,
-                    cause,
-                    Some(*sub_region),
-                    Some(*sup_region),
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                None,
+                cause,
+                Some(*sub_region),
+                Some(*sup_region),
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             Some(RegionResolutionError::ConcreteFailure(
                 SubregionOrigin::Subtype(TypeTrace {
@@ -124,19 +128,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 }),
                 sub_region @ ty::RePlaceholder(_),
                 sup_region,
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    Some(sup_region),
-                    cause,
-                    Some(*sub_region),
-                    None,
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(sup_region),
+                cause,
+                Some(*sub_region),
+                None,
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             Some(RegionResolutionError::ConcreteFailure(
                 SubregionOrigin::Subtype(TypeTrace {
@@ -145,19 +145,15 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 }),
                 sub_region,
                 sup_region @ ty::RePlaceholder(_),
-            ))
-                if expected.def_id == found.def_id =>
-            {
-                Some(self.try_report_placeholders_trait(
-                    Some(sub_region),
-                    cause,
-                    None,
-                    Some(*sup_region),
-                    expected.def_id,
-                    expected.substs,
-                    found.substs,
-                ))
-            }
+            )) if expected.def_id == found.def_id => Some(self.try_report_placeholders_trait(
+                Some(sub_region),
+                cause,
+                None,
+                Some(*sup_region),
+                expected.def_id,
+                expected.substs,
+                found.substs,
+            )),
 
             _ => None,
         }
@@ -181,12 +177,23 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
         trait_def_id: DefId,
         expected_substs: &'tcx Substs<'tcx>,
         actual_substs: &'tcx Substs<'tcx>,
-    ) -> ErrorReported {
-        let mut err = self.tcx.sess.struct_span_err(
-            cause.span(&self.tcx),
+    ) -> DiagnosticBuilder<'me> {
+        debug!(
+            "try_report_placeholders_trait(\
+             vid={:?}, \
+             sub_placeholder={:?}, \
+             sup_placeholder={:?}, \
+             trait_def_id={:?}, \
+             expected_substs={:?}, \
+             actual_substs={:?})",
+            vid, sub_placeholder, sup_placeholder, trait_def_id, expected_substs, actual_substs
+        );
+
+        let mut err = self.tcx().sess.struct_span_err(
+            cause.span(&self.tcx()),
             &format!(
                 "implementation of `{}` is not general enough",
-                self.tcx.item_path_str(trait_def_id),
+                self.tcx().item_path_str(trait_def_id),
             ),
         );
 
@@ -194,20 +201,20 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
             ObligationCauseCode::ItemObligation(def_id) => {
                 err.note(&format!(
                     "Due to a where-clause on `{}`,",
-                    self.tcx.item_path_str(def_id),
+                    self.tcx().item_path_str(def_id),
                 ));
             }
             _ => (),
         }
 
-        let expected_trait_ref = ty::TraitRef {
+        let expected_trait_ref = self.infcx.resolve_type_vars_if_possible(&ty::TraitRef {
             def_id: trait_def_id,
             substs: expected_substs,
-        };
-        let actual_trait_ref = ty::TraitRef {
+        });
+        let actual_trait_ref = self.infcx.resolve_type_vars_if_possible(&ty::TraitRef {
             def_id: trait_def_id,
             substs: actual_substs,
-        };
+        });
 
         // Search the expected and actual trait references to see (a)
         // whether the sub/sup placeholders appear in them (sometimes
@@ -218,9 +225,11 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
         let mut counter = 0;
         let mut has_sub = None;
         let mut has_sup = None;
-        let mut has_vid = None;
 
-        self.tcx.for_each_free_region(&expected_trait_ref, |r| {
+        let mut actual_has_vid = None;
+        let mut expected_has_vid = None;
+
+        self.tcx().for_each_free_region(&expected_trait_ref, |r| {
             if Some(r) == sub_placeholder && has_sub.is_none() {
                 has_sub = Some(counter);
                 counter += 1;
@@ -228,80 +237,206 @@ impl NiceRegionError<'me, 'gcx, 'tcx> {
                 has_sup = Some(counter);
                 counter += 1;
             }
+
+            if Some(r) == vid && expected_has_vid.is_none() {
+                expected_has_vid = Some(counter);
+                counter += 1;
+            }
         });
 
-        self.tcx.for_each_free_region(&actual_trait_ref, |r| {
-            if Some(r) == vid && has_vid.is_none() {
-                has_vid = Some(counter);
+        self.tcx().for_each_free_region(&actual_trait_ref, |r| {
+            if Some(r) == vid && actual_has_vid.is_none() {
+                actual_has_vid = Some(counter);
                 counter += 1;
             }
         });
 
-        let self_ty_has_vid = self
-            .tcx
+        let actual_self_ty_has_vid = self
+            .tcx()
             .any_free_region_meets(&actual_trait_ref.self_ty(), |r| Some(r) == vid);
 
+        let expected_self_ty_has_vid = self
+            .tcx()
+            .any_free_region_meets(&expected_trait_ref.self_ty(), |r| Some(r) == vid);
+
+        let any_self_ty_has_vid = actual_self_ty_has_vid || expected_self_ty_has_vid;
+
+        debug!(
+            "try_report_placeholders_trait: actual_has_vid={:?}",
+            actual_has_vid
+        );
+        debug!(
+            "try_report_placeholders_trait: expected_has_vid={:?}",
+            expected_has_vid
+        );
+        debug!("try_report_placeholders_trait: has_sub={:?}", has_sub);
+        debug!("try_report_placeholders_trait: has_sup={:?}", has_sup);
+        debug!(
+            "try_report_placeholders_trait: actual_self_ty_has_vid={:?}",
+            actual_self_ty_has_vid
+        );
+        debug!(
+            "try_report_placeholders_trait: expected_self_ty_has_vid={:?}",
+            expected_self_ty_has_vid
+        );
+
+        self.explain_actual_impl_that_was_found(
+            &mut err,
+            sub_placeholder,
+            sup_placeholder,
+            has_sub,
+            has_sup,
+            expected_trait_ref,
+            actual_trait_ref,
+            vid,
+            expected_has_vid,
+            actual_has_vid,
+            any_self_ty_has_vid,
+        );
+
+        err
+    }
+
+    /// Add notes with details about the expected and actual trait refs, with attention to cases
+    /// when placeholder regions are involved: either the trait or the self type containing
+    /// them needs to be mentioned the closest to the placeholders.
+    /// This makes the error messages read better, however at the cost of some complexity
+    /// due to the number of combinations we have to deal with.
+    fn explain_actual_impl_that_was_found(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        sub_placeholder: Option<ty::Region<'tcx>>,
+        sup_placeholder: Option<ty::Region<'tcx>>,
+        has_sub: Option<usize>,
+        has_sup: Option<usize>,
+        expected_trait_ref: ty::TraitRef<'_>,
+        actual_trait_ref: ty::TraitRef<'_>,
+        vid: Option<ty::Region<'tcx>>,
+        expected_has_vid: Option<usize>,
+        actual_has_vid: Option<usize>,
+        any_self_ty_has_vid: bool,
+    ) {
+        // The weird thing here with the `maybe_highlighting_region` calls and the
+        // the match inside is meant to be like this:
+        //
+        // - The match checks whether the given things (placeholders, etc) appear
+        //   in the types are about to print
+        // - Meanwhile, the `maybe_highlighting_region` calls set up
+        //   highlights so that, if they do appear, we will replace
+        //   them `'0` and whatever.  (This replacement takes place
+        //   inside the closure given to `maybe_highlighting_region`.)
+        //
+        // There is some duplication between the calls -- i.e., the
+        // `maybe_highlighting_region` checks if (e.g.) `has_sub` is
+        // None, an then we check again inside the closure, but this
+        // setup sort of minimized the number of calls and so form.
+
         RegionHighlightMode::maybe_highlighting_region(sub_placeholder, has_sub, || {
             RegionHighlightMode::maybe_highlighting_region(sup_placeholder, has_sup, || {
                 match (has_sub, has_sup) {
                     (Some(n1), Some(n2)) => {
-                        err.note(&format!(
-                            "`{}` must implement `{}` \
-                             for any two lifetimes `'{}` and `'{}`",
-                            expected_trait_ref.self_ty(),
-                            expected_trait_ref,
-                            std::cmp::min(n1, n2),
-                            std::cmp::max(n1, n2),
-                        ));
+                        if any_self_ty_has_vid {
+                            err.note(&format!(
+                                "`{}` would have to be implemented for the type `{}`, \
+                                 for any two lifetimes `'{}` and `'{}`",
+                                expected_trait_ref,
+                                expected_trait_ref.self_ty(),
+                                std::cmp::min(n1, n2),
+                                std::cmp::max(n1, n2),
+                            ));
+                        } else {
+                            err.note(&format!(
+                                "`{}` must implement `{}`, \
+                                 for any two lifetimes `'{}` and `'{}`",
+                                expected_trait_ref.self_ty(),
+                                expected_trait_ref,
+                                std::cmp::min(n1, n2),
+                                std::cmp::max(n1, n2),
+                            ));
+                        }
                     }
                     (Some(n), _) | (_, Some(n)) => {
+                        if any_self_ty_has_vid {
+                            err.note(&format!(
+                                "`{}` would have to be implemented for the type `{}`, \
+                                 for any lifetime `'{}`",
+                                expected_trait_ref,
+                                expected_trait_ref.self_ty(),
+                                n,
+                            ));
+                        } else {
+                            err.note(&format!(
+                                "`{}` must implement `{}`, for any lifetime `'{}`",
+                                expected_trait_ref.self_ty(),
+                                expected_trait_ref,
+                                n,
+                            ));
+                        }
+                    }
+                    (None, None) => RegionHighlightMode::maybe_highlighting_region(
+                        vid,
+                        expected_has_vid,
+                        || {
+                            if let Some(n) = expected_has_vid {
+                                err.note(&format!(
+                                    "`{}` would have to be implemented for the type `{}`, \
+                                     for some specific lifetime `'{}`",
+                                    expected_trait_ref,
+                                    expected_trait_ref.self_ty(),
+                                    n,
+                                ));
+                            } else {
+                                if any_self_ty_has_vid {
+                                    err.note(&format!(
+                                        "`{}` would have to be implemented for the type `{}`",
+                                        expected_trait_ref,
+                                        expected_trait_ref.self_ty(),
+                                    ));
+                                } else {
+                                    err.note(&format!(
+                                        "`{}` must implement `{}`",
+                                        expected_trait_ref.self_ty(),
+                                        expected_trait_ref,
+                                    ));
+                                }
+                            }
+                        },
+                    ),
+                }
+            })
+        });
+
+        RegionHighlightMode::maybe_highlighting_region(
+            vid,
+            actual_has_vid,
+            || match actual_has_vid {
+                Some(n) => {
+                    if any_self_ty_has_vid {
                         err.note(&format!(
-                            "`{}` must implement `{}` \
-                             for any lifetime `'{}`",
-                            expected_trait_ref.self_ty(),
-                            expected_trait_ref,
-                            n,
+                            "but `{}` is actually implemented for the type `{}`, \
+                             for some specific lifetime `'{}`",
+                            actual_trait_ref,
+                            actual_trait_ref.self_ty(),
+                            n
                         ));
-                    }
-                    (None, None) => {
+                    } else {
                         err.note(&format!(
-                            "`{}` must implement `{}`",
-                            expected_trait_ref.self_ty(),
-                            expected_trait_ref,
+                            "but `{}` actually implements `{}`, for some specific lifetime `'{}`",
+                            actual_trait_ref.self_ty(),
+                            actual_trait_ref,
+                            n
                         ));
                     }
                 }
-            })
-        });
 
-        RegionHighlightMode::maybe_highlighting_region(vid, has_vid, || match has_vid {
-            Some(n) => {
-                if self_ty_has_vid {
+                _ => {
                     err.note(&format!(
-                        "but `{}` only implements `{}` for the lifetime `'{}`",
-                        actual_trait_ref.self_ty(),
+                        "but `{}` is actually implemented for the type `{}`",
                         actual_trait_ref,
-                        n
-                    ));
-                } else {
-                    err.note(&format!(
-                        "but `{}` only implements `{}` for some lifetime `'{}`",
                         actual_trait_ref.self_ty(),
-                        actual_trait_ref,
-                        n
                     ));
                 }
-            }
-            None => {
-                err.note(&format!(
-                    "but `{}` only implements `{}`",
-                    actual_trait_ref.self_ty(),
-                    actual_trait_ref,
-                ));
-            }
-        });
-
-        err.emit();
-        ErrorReported
+            },
+        );
     }
 }
diff --git a/src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs b/src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs
index 9fc3bb05cdab1..23acaeb31f8d4 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/static_impl_trait.rs
@@ -1,9 +1,9 @@
 //! Error Reporting for static impl Traits.
 
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use infer::lexical_region_resolve::RegionResolutionError;
-use ty::{BoundRegion, FreeRegion, RegionKind};
-use util::common::ErrorReported;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::infer::lexical_region_resolve::RegionResolutionError;
+use crate::ty::{BoundRegion, FreeRegion, RegionKind};
+use crate::util::common::ErrorReported;
 use errors::Applicability;
 
 impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
@@ -19,13 +19,13 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                     sup_r,
                 ) = error.clone()
             {
-                let anon_reg_sup = self.tcx.is_suitable_region(sup_r)?;
+                let anon_reg_sup = self.tcx().is_suitable_region(sup_r)?;
                 if sub_r == &RegionKind::ReStatic &&
-                    self.tcx.return_type_impl_trait(anon_reg_sup.def_id).is_some()
+                    self.tcx().return_type_impl_trait(anon_reg_sup.def_id).is_some()
                 {
                     let sp = var_origin.span();
                     let return_sp = sub_origin.span();
-                    let mut err = self.tcx.sess.struct_span_err(
+                    let mut err = self.tcx().sess.struct_span_err(
                         sp,
                         "cannot infer an appropriate lifetime",
                     );
@@ -38,7 +38,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                         "...but this borrow...",
                     );
 
-                    let (lifetime, lt_sp_opt) = self.tcx.msg_span_from_free_region(sup_r);
+                    let (lifetime, lt_sp_opt) = self.tcx().msg_span_from_free_region(sup_r);
                     if let Some(lifetime_sp) = lt_sp_opt {
                         err.span_note(
                             lifetime_sp,
@@ -52,8 +52,8 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                         }) => name.to_string(),
                         _ => "'_".to_owned(),
                     };
-                    if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(return_sp) {
-                        err.span_suggestion_with_applicability(
+                    if let Ok(snippet) = self.tcx().sess.source_map().span_to_snippet(return_sp) {
+                        err.span_suggestion(
                             return_sp,
                             &format!(
                                 "you can add a constraint to the return type to make it last \
diff --git a/src/librustc/infer/error_reporting/nice_region_error/util.rs b/src/librustc/infer/error_reporting/nice_region_error/util.rs
index 43590a606ae90..6db1bc382afe9 100644
--- a/src/librustc/infer/error_reporting/nice_region_error/util.rs
+++ b/src/librustc/infer/error_reporting/nice_region_error/util.rs
@@ -1,10 +1,10 @@
 //! Helper functions corresponding to lifetime errors due to
 //! anonymous regions.
 
-use hir;
-use infer::error_reporting::nice_region_error::NiceRegionError;
-use ty::{self, Region, Ty};
-use hir::def_id::DefId;
+use crate::hir;
+use crate::infer::error_reporting::nice_region_error::NiceRegionError;
+use crate::ty::{self, Region, Ty};
+use crate::hir::def_id::DefId;
 use syntax_pos::Span;
 
 // The struct contains the information about the anonymous region
@@ -44,13 +44,13 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         let (id, bound_region) = match *anon_region {
             ty::ReFree(ref free_region) => (free_region.scope, free_region.bound_region),
             ty::ReEarlyBound(ref ebr) => (
-                self.tcx.parent_def_id(ebr.def_id).unwrap(),
+                self.tcx().parent_def_id(ebr.def_id).unwrap(),
                 ty::BoundRegion::BrNamed(ebr.def_id, ebr.name),
             ),
             _ => return None, // not a free region
         };
 
-        let hir = &self.tcx.hir();
+        let hir = &self.tcx().hir();
         if let Some(node_id) = hir.as_local_node_id(id) {
             if let Some(body_id) = hir.maybe_body_owned_by(node_id) {
                 let body = hir.body(body_id);
@@ -64,9 +64,9 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
                             // May return None; sometimes the tables are not yet populated.
                             let ty_hir_id = fn_decl.inputs[index].hir_id;
                             let arg_ty_span = hir.span(hir.hir_to_node_id(ty_hir_id));
-                            let ty = tables.node_id_to_type_opt(arg.hir_id)?;
+                            let ty = tables.node_type_opt(arg.hir_id)?;
                             let mut found_anon_region = false;
-                            let new_arg_ty = self.tcx.fold_regions(&ty, &mut false, |r, _| {
+                            let new_arg_ty = self.tcx().fold_regions(&ty, &mut false, |r, _| {
                                 if *r == *anon_region {
                                     found_anon_region = true;
                                     replace_region
@@ -108,10 +108,10 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
         br: ty::BoundRegion,
         decl: &hir::FnDecl,
     ) -> Option<Span> {
-        let ret_ty = self.tcx.type_of(scope_def_id);
+        let ret_ty = self.tcx().type_of(scope_def_id);
         if let ty::FnDef(_, _) = ret_ty.sty {
-            let sig = ret_ty.fn_sig(self.tcx);
-            let late_bound_regions = self.tcx
+            let sig = ret_ty.fn_sig(self.tcx());
+            let late_bound_regions = self.tcx()
                 .collect_referenced_late_bound_regions(&sig.output());
             if late_bound_regions.iter().any(|r| *r == br) {
                 return Some(decl.output.span());
@@ -126,7 +126,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     // enable E0621 for it.
     pub(super) fn is_self_anon(&self, is_first: bool, scope_def_id: DefId) -> bool {
         is_first
-            && self.tcx
+            && self.tcx()
                    .opt_associated_item(scope_def_id)
                    .map(|i| i.method_has_self_argument) == Some(true)
     }
diff --git a/src/librustc/infer/error_reporting/note.rs b/src/librustc/infer/error_reporting/note.rs
index e45a4b17cdd9c..c05c6567bbefa 100644
--- a/src/librustc/infer/error_reporting/note.rs
+++ b/src/librustc/infer/error_reporting/note.rs
@@ -1,7 +1,7 @@
-use infer::{self, InferCtxt, SubregionOrigin};
-use middle::region;
-use ty::{self, Region};
-use ty::error::TypeError;
+use crate::infer::{self, InferCtxt, SubregionOrigin};
+use crate::middle::region;
+use crate::ty::{self, Region};
+use crate::ty::error::TypeError;
 use errors::DiagnosticBuilder;
 
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
@@ -31,8 +31,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                               "...so that reference does not outlive borrowed content");
             }
             infer::ReborrowUpvar(span, ref upvar_id) => {
-                let var_node_id = self.tcx.hir().hir_to_node_id(upvar_id.var_path.hir_id);
-                let var_name = self.tcx.hir().name(var_node_id);
+                let var_name = self.tcx.hir().name_by_hir_id(upvar_id.var_path.hir_id);
                 err.span_note(span,
                               &format!("...so that closure can access `{}`", var_name));
             }
@@ -164,8 +163,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 err
             }
             infer::ReborrowUpvar(span, ref upvar_id) => {
-                let var_node_id = self.tcx.hir().hir_to_node_id(upvar_id.var_path.hir_id);
-                let var_name = self.tcx.hir().name(var_node_id);
+                let var_name = self.tcx.hir().name_by_hir_id(upvar_id.var_path.hir_id);
                 let mut err = struct_span_err!(self.tcx.sess,
                                                span,
                                                E0313,
diff --git a/src/librustc/infer/freshen.rs b/src/librustc/infer/freshen.rs
index 74abcf82529cb..201717b34ee41 100644
--- a/src/librustc/infer/freshen.rs
+++ b/src/librustc/infer/freshen.rs
@@ -31,9 +31,9 @@
 //! variable only once, and it does so as soon as it can, so it is reasonable to ask what the type
 //! inferencer knows "so far".
 
-use ty::{self, Ty, TyCtxt, TypeFoldable};
-use ty::fold::TypeFolder;
-use util::nodemap::FxHashMap;
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
+use crate::ty::fold::TypeFolder;
+use crate::util::nodemap::FxHashMap;
 
 use std::collections::hash_map::Entry;
 
diff --git a/src/librustc/infer/fudge.rs b/src/librustc/infer/fudge.rs
index a38db5d210f7b..5f6a8802b4def 100644
--- a/src/librustc/infer/fudge.rs
+++ b/src/librustc/infer/fudge.rs
@@ -1,6 +1,6 @@
-use infer::type_variable::TypeVariableMap;
-use ty::{self, Ty, TyCtxt};
-use ty::fold::{TypeFoldable, TypeFolder};
+use crate::infer::type_variable::TypeVariableMap;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::fold::{TypeFoldable, TypeFolder};
 
 use super::InferCtxt;
 use super::RegionVariableOrigin;
@@ -22,13 +22,13 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// closure `f`. In our example above, what this closure will do
     /// is to unify the expectation (`Option<&[u32]>`) with the actual
     /// return type (`Option<?T>`, where `?T` represents the variable
-    /// instantiated for `T`).  This will cause `?T` to be unified
+    /// instantiated for `T`). This will cause `?T` to be unified
     /// with `&?a [u32]`, where `?a` is a fresh lifetime variable. The
     /// input type (`?T`) is then returned by `f()`.
     ///
     /// At this point, `fudge_regions_if_ok` will normalize all type
     /// variables, converting `?T` to `&?a [u32]` and end the
-    /// snapshot.  The problem is that we can't just return this type
+    /// snapshot. The problem is that we can't just return this type
     /// out, because it references the region variable `?a`, and that
     /// region variable was popped when we popped the snapshot.
     ///
diff --git a/src/librustc/infer/glb.rs b/src/librustc/infer/glb.rs
index 635a6d00270b7..910c6571853dc 100644
--- a/src/librustc/infer/glb.rs
+++ b/src/librustc/infer/glb.rs
@@ -3,9 +3,9 @@ use super::InferCtxt;
 use super::lattice::{self, LatticeDir};
 use super::Subtype;
 
-use traits::ObligationCause;
-use ty::{self, Ty, TyCtxt};
-use ty::relate::{Relate, RelateResult, TypeRelation};
+use crate::traits::ObligationCause;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::relate::{Relate, RelateResult, TypeRelation};
 
 /// "Greatest lower bound" (common subtype)
 pub struct Glb<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
diff --git a/src/librustc/infer/higher_ranked/README.md b/src/librustc/infer/higher_ranked/README.md
index b1ac8bae4fb98..e7afaa5beb0a7 100644
--- a/src/librustc/infer/higher_ranked/README.md
+++ b/src/librustc/infer/higher_ranked/README.md
@@ -1,403 +1,8 @@
-# Skolemization and functions
+To learn more about how Higher-ranked trait bounds work in the _old_ trait
+solver, see [this chapter][oldhrtb] of the rustc-guide.
 
-One of the trickiest and most subtle aspects of regions is dealing
-with higher-ranked things which include bound region variables, such
-as function types. I strongly suggest that if you want to understand
-the situation, you read this paper (which is, admittedly, very long,
-but you don't have to read the whole thing):
+To learn more about how they work in the _new_ trait solver, see [this
+chapter][newhrtb].
 
-http://research.microsoft.com/en-us/um/people/simonpj/papers/higher-rank/
-
-Although my explanation will never compete with SPJ's (for one thing,
-his is approximately 100 pages), I will attempt to explain the basic
-problem and also how we solve it. Note that the paper only discusses
-subtyping, not the computation of LUB/GLB.
-
-The problem we are addressing is that there is a kind of subtyping
-between functions with bound region parameters. Consider, for
-example, whether the following relation holds:
-
-    for<'a> fn(&'a isize) <: for<'b> fn(&'b isize)? (Yes, a => b)
-
-The answer is that of course it does. These two types are basically
-the same, except that in one we used the name `a` and one we used
-the name `b`.
-
-In the examples that follow, it becomes very important to know whether
-a lifetime is bound in a function type (that is, is a lifetime
-parameter) or appears free (is defined in some outer scope).
-Therefore, from now on I will always write the bindings explicitly,
-using the Rust syntax `for<'a> fn(&'a isize)` to indicate that `a` is a
-lifetime parameter.
-
-Now let's consider two more function types. Here, we assume that the
-`'b` lifetime is defined somewhere outside and hence is not a lifetime
-parameter bound by the function type (it "appears free"):
-
-    for<'a> fn(&'a isize) <: fn(&'b isize)? (Yes, a => b)
-
-This subtyping relation does in fact hold. To see why, you have to
-consider what subtyping means. One way to look at `T1 <: T2` is to
-say that it means that it is always ok to treat an instance of `T1` as
-if it had the type `T2`. So, with our functions, it is always ok to
-treat a function that can take pointers with any lifetime as if it
-were a function that can only take a pointer with the specific
-lifetime `'b`. After all, `'b` is a lifetime, after all, and
-the function can take values of any lifetime.
-
-You can also look at subtyping as the *is a* relationship. This amounts
-to the same thing: a function that accepts pointers with any lifetime
-*is a* function that accepts pointers with some specific lifetime.
-
-So, what if we reverse the order of the two function types, like this:
-
-    fn(&'b isize) <: for<'a> fn(&'a isize)? (No)
-
-Does the subtyping relationship still hold?  The answer of course is
-no. In this case, the function accepts *only the lifetime `'b`*,
-so it is not reasonable to treat it as if it were a function that
-accepted any lifetime.
-
-What about these two examples:
-
-    for<'a,'b> fn(&'a isize, &'b isize) <: for<'a>    fn(&'a isize, &'a isize)? (Yes)
-    for<'a>    fn(&'a isize, &'a isize) <: for<'a,'b> fn(&'a isize, &'b isize)? (No)
-
-Here, it is true that functions which take two pointers with any two
-lifetimes can be treated as if they only accepted two pointers with
-the same lifetime, but not the reverse.
-
-## The algorithm
-
-Here is the algorithm we use to perform the subtyping check:
-
-1. Replace all bound regions in the subtype with new variables
-2. Replace all bound regions in the supertype with placeholder
-   equivalents. A "placeholder" region is just a new fresh region
-   name.
-3. Check that the parameter and return types match as normal
-4. Ensure that no placeholder regions 'leak' into region variables
-   visible from "the outside"
-
-Let's walk through some examples and see how this algorithm plays out.
-
-#### First example
-
-We'll start with the first example, which was:
-
-    1. for<'a> fn(&'a T) <: for<'b> fn(&'b T)?        Yes: a -> b
-
-After steps 1 and 2 of the algorithm we will have replaced the types
-like so:
-
-    1. fn(&'A T) <: fn(&'x T)?
-
-Here the upper case `&A` indicates a *region variable*, that is, a
-region whose value is being inferred by the system. I also replaced
-`&b` with `&x`---I'll use letters late in the alphabet (`x`, `y`, `z`)
-to indicate placeholder region names. We can assume they don't appear
-elsewhere. Note that neither the sub- nor the supertype bind any
-region names anymore (as indicated by the absence of `<` and `>`).
-
-The next step is to check that the parameter types match. Because
-parameters are contravariant, this means that we check whether:
-
-    &'x T <: &'A T
-
-Region pointers are contravariant so this implies that
-
-    &A <= &x
-
-must hold, where `<=` is the subregion relationship. Processing
-*this* constrain simply adds a constraint into our graph that `&A <=
-&x` and is considered successful (it can, for example, be satisfied by
-choosing the value `&x` for `&A`).
-
-So far we have encountered no error, so the subtype check succeeds.
-
-#### The third example
-
-Now let's look first at the third example, which was:
-
-    3. fn(&'a T)    <: for<'b> fn(&'b T)?        No!
-
-After steps 1 and 2 of the algorithm we will have replaced the types
-like so:
-
-    3. fn(&'a T) <: fn(&'x T)?
-
-This looks pretty much the same as before, except that on the LHS
-`'a` was not bound, and hence was left as-is and not replaced with
-a variable. The next step is again to check that the parameter types
-match. This will ultimately require (as before) that `'a` <= `&x`
-must hold: but this does not hold. `self` and `x` are both distinct
-free regions. So the subtype check fails.
-
-#### Checking for placeholder leaks
-
-You may be wondering about that mysterious last step in the algorithm.
-So far it has not been relevant. The purpose of that last step is to
-catch something like *this*:
-
-    for<'a> fn() -> fn(&'a T) <: fn() -> for<'b> fn(&'b T)?   No.
-
-Here the function types are the same but for where the binding occurs.
-The subtype returns a function that expects a value in precisely one
-region. The supertype returns a function that expects a value in any
-region. If we allow an instance of the subtype to be used where the
-supertype is expected, then, someone could call the fn and think that
-the return value has type `fn<b>(&'b T)` when it really has type
-`fn(&'a T)` (this is case #3, above). Bad.
-
-So let's step through what happens when we perform this subtype check.
-We first replace the bound regions in the subtype (the supertype has
-no bound regions). This gives us:
-
-    fn() -> fn(&'A T) <: fn() -> for<'b> fn(&'b T)?
-
-Now we compare the return types, which are covariant, and hence we have:
-
-    fn(&'A T) <: for<'b> fn(&'b T)?
-
-Here we replace the bound region in the supertype with a placeholder to yield:
-
-    fn(&'A T) <: fn(&'x T)?
-
-And then proceed to compare the argument types:
-
-    &'x T <: &'A T
-    'A <= 'x
-
-Finally, this is where it gets interesting!  This is where an error
-*should* be reported. But in fact this will not happen. The reason why
-is that `A` is a variable: we will infer that its value is the fresh
-region `x` and think that everything is happy. In fact, this behavior
-is *necessary*, it was key to the first example we walked through.
-
-The difference between this example and the first one is that the variable
-`A` already existed at the point where the placeholders were added. In
-the first example, you had two functions:
-
-    for<'a> fn(&'a T) <: for<'b> fn(&'b T)
-
-and hence `&A` and `&x` were created "together". In general, the
-intention of the placeholder names is that they are supposed to be
-fresh names that could never be equal to anything from the outside.
-But when inference comes into play, we might not be respecting this
-rule.
-
-So the way we solve this is to add a fourth step that examines the
-constraints that refer to placeholder names. Basically, consider a
-non-directed version of the constraint graph. Let `Tainted(x)` be the
-set of all things reachable from a placeholder variable `x`.
-`Tainted(x)` should not contain any regions that existed before the
-step at which the placeholders were created. So this case here
-would fail because `&x` was created alone, but is relatable to `&A`.
-
-## Computing the LUB and GLB
-
-The paper I pointed you at is written for Haskell. It does not
-therefore considering subtyping and in particular does not consider
-LUB or GLB computation. We have to consider this. Here is the
-algorithm I implemented.
-
-First though, let's discuss what we are trying to compute in more
-detail. The LUB is basically the "common supertype" and the GLB is
-"common subtype"; one catch is that the LUB should be the
-*most-specific* common supertype and the GLB should be *most general*
-common subtype (as opposed to any common supertype or any common
-subtype).
-
-Anyway, to help clarify, here is a table containing some function
-pairs and their LUB/GLB (for conciseness, in this table, I'm just
-including the lifetimes here, not the rest of the types, and I'm
-writing `fn<>` instead of `for<> fn`):
-
-```
-Type 1                Type 2                LUB                    GLB
-fn<'a>('a)            fn('X)                fn('X)                 fn<'a>('a)
-fn('a)                fn('X)                --                     fn<'a>('a)
-fn<'a,'b>('a, 'b)     fn<'x>('x, 'x)        fn<'a>('a, 'a)         fn<'a,'b>('a, 'b)
-fn<'a,'b>('a, 'b, 'a) fn<'x,'y>('x, 'y, 'y) fn<'a>('a, 'a, 'a)     fn<'a,'b,'c>('a,'b,'c)
-```
-
-### Conventions
-
-I use lower-case letters (e.g., `&a`) for bound regions and upper-case
-letters for free regions (`&A`).  Region variables written with a
-dollar-sign (e.g., `$a`).  I will try to remember to enumerate the
-bound-regions on the fn type as well (e.g., `for<'a> fn(&a)`).
-
-### High-level summary
-
-Both the LUB and the GLB algorithms work in a similar fashion.  They
-begin by replacing all bound regions (on both sides) with fresh region
-inference variables.  Therefore, both functions are converted to types
-that contain only free regions.  We can then compute the LUB/GLB in a
-straightforward way, as described in `combine.rs`.  This results in an
-interim type T.  The algorithms then examine the regions that appear
-in T and try to, in some cases, replace them with bound regions to
-yield the final result.
-
-To decide whether to replace a region `R` that appears in `T` with
-a bound region, the algorithms make use of two bits of
-information.  First is a set `V` that contains all region
-variables created as part of the LUB/GLB computation (roughly; see
-`region_vars_confined_to_snapshot()` for full details). `V` will
-contain the region variables created to replace the bound regions
-in the input types, but it also contains 'intermediate' variables
-created to represent the LUB/GLB of individual regions.
-Basically, when asked to compute the LUB/GLB of a region variable
-with another region, the inferencer cannot oblige immediately
-since the values of that variables are not known.  Therefore, it
-creates a new variable that is related to the two regions.  For
-example, the LUB of two variables `$x` and `$y` is a fresh
-variable `$z` that is constrained such that `$x <= $z` and `$y <=
-$z`.  So `V` will contain these intermediate variables as well.
-
-The other important factor in deciding how to replace a region in T is
-the function `Tainted($r)` which, for a region variable, identifies
-all regions that the region variable is related to in some way
-(`Tainted()` made an appearance in the subtype computation as well).
-
-### LUB
-
-The LUB algorithm proceeds in three steps:
-
-1. Replace all bound regions (on both sides) with fresh region
-   inference variables.
-2. Compute the LUB "as normal", meaning compute the GLB of each
-   pair of argument types and the LUB of the return types and
-   so forth.  Combine those to a new function type `F`.
-3. Replace each region `R` that appears in `F` as follows:
-   - Let `V` be the set of variables created during the LUB
-     computational steps 1 and 2, as described in the previous section.
-   - If `R` is not in `V`, replace `R` with itself.
-   - If `Tainted(R)` contains a region that is not in `V`,
-     replace `R` with itself.
-   - Otherwise, select the earliest variable in `Tainted(R)` that originates
-     from the left-hand side and replace `R` with the bound region that
-     this variable was a replacement for.
-
-So, let's work through the simplest example: `fn(&A)` and `for<'a> fn(&a)`.
-In this case, `&a` will be replaced with `$a` and the interim LUB type
-`fn($b)` will be computed, where `$b=GLB(&A,$a)`.  Therefore, `V =
-{$a, $b}` and `Tainted($b) = { $b, $a, &A }`.  When we go to replace
-`$b`, we find that since `&A \in Tainted($b)` is not a member of `V`,
-we leave `$b` as is.  When region inference happens, `$b` will be
-resolved to `&A`, as we wanted.
-
-Let's look at a more complex one: `fn(&a, &b)` and `fn(&x, &x)`.  In
-this case, we'll end up with a (pre-replacement) LUB type of `fn(&g,
-&h)` and a graph that looks like:
-
-```
-     $a        $b     *--$x
-       \        \    /  /
-        \        $h-*  /
-         $g-----------*
-```
-
-Here `$g` and `$h` are fresh variables that are created to represent
-the LUB/GLB of things requiring inference.  This means that `V` and
-`Tainted` will look like:
-
-```
-V = {$a, $b, $g, $h, $x}
-Tainted($g) = Tainted($h) = { $a, $b, $h, $g, $x }
-```
-
-Therefore we replace both `$g` and `$h` with `$a`, and end up
-with the type `fn(&a, &a)`.
-
-### GLB
-
-The procedure for computing the GLB is similar.  The difference lies
-in computing the replacements for the various variables. For each
-region `R` that appears in the type `F`, we again compute `Tainted(R)`
-and examine the results:
-
-1. If `R` is not in `V`, it is not replaced.
-2. Else, if `Tainted(R)` contains only variables in `V`, and it
-   contains exactly one variable from the LHS and one variable from
-   the RHS, then `R` can be mapped to the bound version of the
-   variable from the LHS.
-3. Else, if `Tainted(R)` contains no variable from the LHS and no
-   variable from the RHS, then `R` can be mapped to itself.
-4. Else, `R` is mapped to a fresh bound variable.
-
-These rules are pretty complex.  Let's look at some examples to see
-how they play out.
-
-Out first example was `fn(&a)` and `fn(&X)`.  In this case, `&a` will
-be replaced with `$a` and we will ultimately compute a
-(pre-replacement) GLB type of `fn($g)` where `$g=LUB($a,&X)`.
-Therefore, `V={$a,$g}` and `Tainted($g)={$g,$a,&X}.  To find the
-replacement for `$g` we consult the rules above:
-- Rule (1) does not apply because `$g \in V`
-- Rule (2) does not apply because `&X \in Tainted($g)`
-- Rule (3) does not apply because `$a \in Tainted($g)`
-- Hence, by rule (4), we replace `$g` with a fresh bound variable `&z`.
-So our final result is `fn(&z)`, which is correct.
-
-The next example is `fn(&A)` and `fn(&Z)`. In this case, we will again
-have a (pre-replacement) GLB of `fn(&g)`, where `$g = LUB(&A,&Z)`.
-Therefore, `V={$g}` and `Tainted($g) = {$g, &A, &Z}`.  In this case,
-by rule (3), `$g` is mapped to itself, and hence the result is
-`fn($g)`.  This result is correct (in this case, at least), but it is
-indicative of a case that *can* lead us into concluding that there is
-no GLB when in fact a GLB does exist.  See the section "Questionable
-Results" below for more details.
-
-The next example is `fn(&a, &b)` and `fn(&c, &c)`. In this case, as
-before, we'll end up with `F=fn($g, $h)` where `Tainted($g) =
-Tainted($h) = {$g, $h, $a, $b, $c}`.  Only rule (4) applies and hence
-we'll select fresh bound variables `y` and `z` and wind up with
-`fn(&y, &z)`.
-
-For the last example, let's consider what may seem trivial, but is
-not: `fn(&a, &a)` and `fn(&b, &b)`.  In this case, we'll get `F=fn($g,
-$h)` where `Tainted($g) = {$g, $a, $x}` and `Tainted($h) = {$h, $a,
-$x}`.  Both of these sets contain exactly one bound variable from each
-side, so we'll map them both to `&a`, resulting in `fn(&a, &a)`, which
-is the desired result.
-
-### Shortcomings and correctness
-
-You may be wondering whether this algorithm is correct.  The answer is
-"sort of".  There are definitely cases where they fail to compute a
-result even though a correct result exists.  I believe, though, that
-if they succeed, then the result is valid, and I will attempt to
-convince you.  The basic argument is that the "pre-replacement" step
-computes a set of constraints.  The replacements, then, attempt to
-satisfy those constraints, using bound identifiers where needed.
-
-For now I will briefly go over the cases for LUB/GLB and identify
-their intent:
-
-- LUB:
-  - The region variables that are substituted in place of bound regions
-    are intended to collect constraints on those bound regions.
-  - If Tainted(R) contains only values in V, then this region is unconstrained
-    and can therefore be generalized, otherwise it cannot.
-- GLB:
-  - The region variables that are substituted in place of bound regions
-    are intended to collect constraints on those bound regions.
-  - If Tainted(R) contains exactly one variable from each side, and
-    only variables in V, that indicates that those two bound regions
-    must be equated.
-  - Otherwise, if Tainted(R) references any variables from left or right
-    side, then it is trying to combine a bound region with a free one or
-    multiple bound regions, so we need to select fresh bound regions.
-
-Sorry this is more of a shorthand to myself.  I will try to write up something
-more convincing in the future.
-
-#### Where are the algorithms wrong?
-
-- The pre-replacement computation can fail even though using a
-  bound-region would have succeeded.
-- We will compute GLB(fn(fn($a)), fn(fn($b))) as fn($c) where $c is the
-  GLB of $a and $b.  But if inference finds that $a and $b must be mapped
-  to regions without a GLB, then this is effectively a failure to compute
-  the GLB.  However, the result `fn<$c>(fn($c))` is a valid GLB.
+[oldhrtb]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
+[newhrtb]: https://rust-lang.github.io/rustc-guide/borrow_check/region_inference.html#placeholders-and-universes
diff --git a/src/librustc/infer/higher_ranked/mod.rs b/src/librustc/infer/higher_ranked/mod.rs
index 709e8c0ba9b24..7c83fe7fd6946 100644
--- a/src/librustc/infer/higher_ranked/mod.rs
+++ b/src/librustc/infer/higher_ranked/mod.rs
@@ -4,8 +4,9 @@
 use super::combine::CombineFields;
 use super::{HigherRankedType, InferCtxt, PlaceholderMap};
 
-use ty::relate::{Relate, RelateResult, TypeRelation};
-use ty::{self, Binder, TypeFoldable};
+use crate::infer::CombinedSnapshot;
+use crate::ty::relate::{Relate, RelateResult, TypeRelation};
+use crate::ty::{self, Binder, TypeFoldable};
 
 impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
     pub fn higher_ranked_sub<T>(
@@ -29,32 +30,37 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
 
         let span = self.trace.cause.span;
 
-        // First, we instantiate each bound region in the supertype with a
-        // fresh placeholder region.
-        let (b_prime, _) = self.infcx.replace_bound_vars_with_placeholders(b);
+        return self.infcx.commit_if_ok(|snapshot| {
+            // First, we instantiate each bound region in the supertype with a
+            // fresh placeholder region.
+            let (b_prime, placeholder_map) = self.infcx.replace_bound_vars_with_placeholders(b);
 
-        // Next, we instantiate each bound region in the subtype
-        // with a fresh region variable. These region variables --
-        // but no other pre-existing region variables -- can name
-        // the placeholders.
-        let (a_prime, _) =
-            self.infcx
-                .replace_bound_vars_with_fresh_vars(span, HigherRankedType, a);
+            // Next, we instantiate each bound region in the subtype
+            // with a fresh region variable. These region variables --
+            // but no other pre-existing region variables -- can name
+            // the placeholders.
+            let (a_prime, _) =
+                self.infcx
+                    .replace_bound_vars_with_fresh_vars(span, HigherRankedType, a);
+
+            debug!("a_prime={:?}", a_prime);
+            debug!("b_prime={:?}", b_prime);
 
-        debug!("a_prime={:?}", a_prime);
-        debug!("b_prime={:?}", b_prime);
+            // Compare types now that bound regions have been replaced.
+            let result = self.sub(a_is_expected).relate(&a_prime, &b_prime)?;
 
-        // Compare types now that bound regions have been replaced.
-        let result = self.sub(a_is_expected).relate(&a_prime, &b_prime)?;
+            self.infcx
+                .leak_check(!a_is_expected, &placeholder_map, snapshot)?;
 
-        debug!("higher_ranked_sub: OK result={:?}", result);
+            debug!("higher_ranked_sub: OK result={:?}", result);
 
-        Ok(ty::Binder::bind(result))
+            Ok(ty::Binder::bind(result))
+        });
     }
 }
 
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
-    /// Replace all regions (resp. types) bound by `binder` with placeholder
+    /// Replaces all regions (resp. types) bound by `binder` with placeholder
     /// regions (resp. types) and return a map indicating which bound-region
     /// placeholder region. This is the first step of checking subtyping
     /// when higher-ranked things are involved.
@@ -72,10 +78,10 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
     pub fn replace_bound_vars_with_placeholders<T>(
         &self,
-        binder: &ty::Binder<T>
+        binder: &ty::Binder<T>,
     ) -> (T, PlaceholderMap<'tcx>)
     where
-        T: TypeFoldable<'tcx>
+        T: TypeFoldable<'tcx>,
     {
         let next_universe = self.create_next_universe();
 
@@ -96,12 +102,25 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         let (result, map) = self.tcx.replace_bound_vars(binder, fld_r, fld_t);
 
         debug!(
-            "replace_bound_vars_with_placeholders(binder={:?}, result={:?}, map={:?})",
-            binder,
-            result,
-            map
+            "replace_bound_vars_with_placeholders(\
+             next_universe={:?}, \
+             binder={:?}, \
+             result={:?}, \
+             map={:?})",
+            next_universe, binder, result, map,
         );
 
         (result, map)
     }
+
+    /// See `infer::region_constraints::RegionConstraintCollector::leak_check`.
+    pub fn leak_check(
+        &self,
+        overly_polymorphic: bool,
+        placeholder_map: &PlaceholderMap<'tcx>,
+        snapshot: &CombinedSnapshot<'_, 'tcx>,
+    ) -> RelateResult<'tcx, ()> {
+        self.borrow_region_constraints()
+            .leak_check(self.tcx, overly_polymorphic, placeholder_map, snapshot)
+    }
 }
diff --git a/src/librustc/infer/lattice.rs b/src/librustc/infer/lattice.rs
index a8794b4076a9d..e40bb97240763 100644
--- a/src/librustc/infer/lattice.rs
+++ b/src/librustc/infer/lattice.rs
@@ -1,7 +1,7 @@
 //! # Lattice Variables
 //!
 //! This file contains generic code for operating on inference variables
-//! that are characterized by an upper- and lower-bound.  The logic and
+//! that are characterized by an upper- and lower-bound. The logic and
 //! reasoning is explained in detail in the large comment in `infer.rs`.
 //!
 //! The code in here is defined quite generically so that it can be
@@ -13,7 +13,7 @@
 //!
 //! Although all the functions are generic, we generally write the
 //! comments in a way that is specific to type variables and the LUB
-//! operation.  It's just easier that way.
+//! operation. It's just easier that way.
 //!
 //! In general all of the functions are defined parametrically
 //! over a `LatticeValue`, which is a value defined with respect to
@@ -22,10 +22,10 @@
 use super::InferCtxt;
 use super::type_variable::TypeVariableOrigin;
 
-use traits::ObligationCause;
-use ty::TyVar;
-use ty::{self, Ty};
-use ty::relate::{RelateResult, TypeRelation};
+use crate::traits::ObligationCause;
+use crate::ty::TyVar;
+use crate::ty::{self, Ty};
+use crate::ty::relate::{RelateResult, TypeRelation};
 
 pub trait LatticeDir<'f, 'gcx: 'f+'tcx, 'tcx: 'f> : TypeRelation<'f, 'gcx, 'tcx> {
     fn infcx(&self) -> &'f InferCtxt<'f, 'gcx, 'tcx>;
diff --git a/src/librustc/infer/lexical_region_resolve/README.md b/src/librustc/infer/lexical_region_resolve/README.md
index 4483e522f3a1f..56320636a6743 100644
--- a/src/librustc/infer/lexical_region_resolve/README.md
+++ b/src/librustc/infer/lexical_region_resolve/README.md
@@ -2,8 +2,12 @@
 
 > WARNING: This README is obsolete and will be removed soon! For
 > more info on how the current borrowck works, see the [rustc guide].
+>
+> As of edition 2018, region inference is done using Non-lexical lifetimes,
+> which is described in the guide and [this RFC].
 
 [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/borrowck.html
+[this RFC]: https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md
 
 ## Terminology
 
diff --git a/src/librustc/infer/lexical_region_resolve/graphviz.rs b/src/librustc/infer/lexical_region_resolve/graphviz.rs
index 7ce2aba54f5cc..073a3f74422c6 100644
--- a/src/librustc/infer/lexical_region_resolve/graphviz.rs
+++ b/src/librustc/infer/lexical_region_resolve/graphviz.rs
@@ -8,14 +8,14 @@
 /// For clarity, rename the graphviz crate locally to dot.
 use graphviz as dot;
 
-use hir::def_id::DefIndex;
-use ty;
-use middle::free_region::RegionRelations;
-use middle::region;
+use crate::hir::def_id::DefIndex;
+use crate::ty;
+use crate::middle::free_region::RegionRelations;
+use crate::middle::region;
 use super::Constraint;
-use infer::SubregionOrigin;
-use infer::region_constraints::RegionConstraintData;
-use util::nodemap::{FxHashMap, FxHashSet};
+use crate::infer::SubregionOrigin;
+use crate::infer::region_constraints::RegionConstraintData;
+use crate::util::nodemap::{FxHashMap, FxHashSet};
 
 use std::borrow::Cow;
 use std::collections::hash_map::Entry::Vacant;
diff --git a/src/librustc/infer/lexical_region_resolve/mod.rs b/src/librustc/infer/lexical_region_resolve/mod.rs
index 39ce8cc621b49..03ade88253682 100644
--- a/src/librustc/infer/lexical_region_resolve/mod.rs
+++ b/src/librustc/infer/lexical_region_resolve/mod.rs
@@ -1,13 +1,13 @@
-//! The code to do lexical region resolution.
-
-use infer::region_constraints::Constraint;
-use infer::region_constraints::GenericKind;
-use infer::region_constraints::RegionConstraintData;
-use infer::region_constraints::VarInfos;
-use infer::region_constraints::VerifyBound;
-use infer::RegionVariableOrigin;
-use infer::SubregionOrigin;
-use middle::free_region::RegionRelations;
+//! Lexical region resolution.
+
+use crate::infer::region_constraints::Constraint;
+use crate::infer::region_constraints::GenericKind;
+use crate::infer::region_constraints::RegionConstraintData;
+use crate::infer::region_constraints::VarInfos;
+use crate::infer::region_constraints::VerifyBound;
+use crate::infer::RegionVariableOrigin;
+use crate::infer::SubregionOrigin;
+use crate::middle::free_region::RegionRelations;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::graph::implementation::{
     Direction, Graph, NodeIndex, INCOMING, OUTGOING,
@@ -16,11 +16,11 @@ use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use smallvec::SmallVec;
 use std::fmt;
 use std::u32;
-use ty::fold::TypeFoldable;
-use ty::{self, Ty, TyCtxt};
-use ty::{ReEarlyBound, ReEmpty, ReErased, ReFree, ReStatic};
-use ty::{ReLateBound, ReScope, RePlaceholder, ReVar};
-use ty::{Region, RegionVid};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::{ReEarlyBound, ReEmpty, ReErased, ReFree, ReStatic};
+use crate::ty::{ReLateBound, ReScope, RePlaceholder, ReVar};
+use crate::ty::{Region, RegionVid};
 
 mod graphviz;
 
@@ -186,34 +186,39 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
     }
 
     fn expansion(&self, var_values: &mut LexicalRegionResolutions<'tcx>) {
-        self.iterate_until_fixed_point("Expansion", |constraint, origin| {
-            debug!("expansion: constraint={:?} origin={:?}", constraint, origin);
-            match *constraint {
+        self.iterate_until_fixed_point("Expansion", |constraint| {
+            debug!("expansion: constraint={:?}", constraint);
+            let (a_region, b_vid, b_data, retain) = match *constraint {
                 Constraint::RegSubVar(a_region, b_vid) => {
                     let b_data = var_values.value_mut(b_vid);
-                    (self.expand_node(a_region, b_vid, b_data), false)
+                    (a_region, b_vid, b_data, false)
                 }
                 Constraint::VarSubVar(a_vid, b_vid) => match *var_values.value(a_vid) {
-                    VarValue::ErrorValue => (false, false),
+                    VarValue::ErrorValue => return (false, false),
                     VarValue::Value(a_region) => {
-                        let b_node = var_values.value_mut(b_vid);
-                        let changed = self.expand_node(a_region, b_vid, b_node);
-                        let retain = match *b_node {
+                        let b_data = var_values.value_mut(b_vid);
+                        let retain = match *b_data {
                             VarValue::Value(ReStatic) | VarValue::ErrorValue => false,
                             _ => true
                         };
-                        (changed, retain)
+                        (a_region, b_vid, b_data, retain)
                     }
                 },
                 Constraint::RegSubReg(..) | Constraint::VarSubReg(..) => {
                     // These constraints are checked after expansion
                     // is done, in `collect_errors`.
-                    (false, false)
+                    return (false, false)
                 }
-            }
+            };
+
+            let changed = self.expand_node(a_region, b_vid, b_data);
+            (changed, retain)
         })
     }
 
+    // This function is very hot in some workloads. There's a single callsite
+    // so always inlining is ok even though it's large.
+    #[inline(always)]
     fn expand_node(
         &self,
         a_region: Region<'tcx>,
@@ -236,6 +241,14 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
 
         match *b_data {
             VarValue::Value(cur_region) => {
+                // Identical scopes can show up quite often, if the fixed point
+                // iteration converges slowly, skip them
+                if let (ReScope(a_scope), ReScope(cur_scope)) = (a_region, cur_region) {
+                    if a_scope == cur_scope {
+                        return false;
+                    }
+                }
+
                 let mut lub = self.lub_concrete_regions(a_region, cur_region);
                 if lub == cur_region {
                     return false;
@@ -275,12 +288,6 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
     fn lub_concrete_regions(&self, a: Region<'tcx>, b: Region<'tcx>) -> Region<'tcx> {
         let tcx = self.tcx();
 
-        // Equal scopes can show up quite often, if the fixed point
-        // iteration converges slowly, skip them
-        if a == b {
-            return a;
-        }
-
         match (a, b) {
             (&ty::ReClosureBound(..), _)
             | (_, &ty::ReClosureBound(..))
@@ -485,20 +492,20 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
             match *value {
                 VarValue::Value(_) => { /* Inference successful */ }
                 VarValue::ErrorValue => {
-                    /* Inference impossible, this value contains
+                    /* Inference impossible: this value contains
                        inconsistent constraints.
 
                        I think that in this case we should report an
-                       error now---unlike the case above, we can't
+                       error now -- unlike the case above, we can't
                        wait to see whether the user needs the result
-                       of this variable.  The reason is that the mere
+                       of this variable. The reason is that the mere
                        existence of this variable implies that the
                        region graph is inconsistent, whether or not it
                        is used.
 
                        For example, we may have created a region
                        variable that is the GLB of two other regions
-                       which do not have a GLB.  Even if that variable
+                       which do not have a GLB. Even if that variable
                        is not used, it implies that those two regions
                        *should* have a GLB.
 
@@ -722,18 +729,17 @@ impl<'cx, 'gcx, 'tcx> LexicalResolver<'cx, 'gcx, 'tcx> {
     }
 
     fn iterate_until_fixed_point<F>(&self, tag: &str, mut body: F)
-    where
-        F: FnMut(&Constraint<'tcx>, &SubregionOrigin<'tcx>) -> (bool, bool),
+        where F: FnMut(&Constraint<'tcx>) -> (bool, bool),
     {
-        let mut constraints: SmallVec<[_; 16]> = self.data.constraints.iter().collect();
+        let mut constraints: SmallVec<[_; 16]> = self.data.constraints.keys().collect();
         let mut iteration = 0;
         let mut changed = true;
         while changed {
             changed = false;
             iteration += 1;
             debug!("---- {} Iteration {}{}", "#", tag, iteration);
-            constraints.retain(|(constraint, origin)| {
-                let (edge_changed, retain) = body(constraint, origin);
+            constraints.retain(|constraint| {
+                let (edge_changed, retain) = body(constraint);
                 if edge_changed {
                     debug!("Updated due to constraint {:?}", constraint);
                     changed = true;
diff --git a/src/librustc/infer/lub.rs b/src/librustc/infer/lub.rs
index 0b9839f69fa2a..f9eb60d82d17b 100644
--- a/src/librustc/infer/lub.rs
+++ b/src/librustc/infer/lub.rs
@@ -3,9 +3,9 @@ use super::InferCtxt;
 use super::lattice::{self, LatticeDir};
 use super::Subtype;
 
-use traits::ObligationCause;
-use ty::{self, Ty, TyCtxt};
-use ty::relate::{Relate, RelateResult, TypeRelation};
+use crate::traits::ObligationCause;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::relate::{Relate, RelateResult, TypeRelation};
 
 /// "Least upper bound" (common supertype)
 pub struct Lub<'combine, 'infcx: 'combine, 'gcx: 'infcx+'tcx, 'tcx: 'infcx> {
diff --git a/src/librustc/infer/mod.rs b/src/librustc/infer/mod.rs
index 958982545750f..ac2ebece442c8 100644
--- a/src/librustc/infer/mod.rs
+++ b/src/librustc/infer/mod.rs
@@ -5,31 +5,33 @@ pub use self::LateBoundRegionConversionTime::*;
 pub use self::RegionVariableOrigin::*;
 pub use self::SubregionOrigin::*;
 pub use self::ValuePairs::*;
-pub use ty::IntVarValue;
+pub use crate::ty::IntVarValue;
+
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::infer::canonical::{Canonical, CanonicalVarValues};
+use crate::middle::free_region::RegionRelations;
+use crate::middle::lang_items;
+use crate::middle::region;
+use crate::session::config::BorrowckMode;
+use crate::traits::{self, ObligationCause, PredicateObligations, TraitEngine};
+use crate::ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::relate::RelateResult;
+use crate::ty::subst::{Kind, Substs};
+use crate::ty::{self, GenericParamDefKind, Ty, TyCtxt, CtxtInterners};
+use crate::ty::{FloatVid, IntVid, TyVid};
+use crate::util::nodemap::FxHashMap;
 
 use arena::SyncDroplessArena;
 use errors::DiagnosticBuilder;
-use hir::def_id::DefId;
-use infer::canonical::{Canonical, CanonicalVarValues};
-use middle::free_region::RegionRelations;
-use middle::lang_items;
-use middle::region;
 use rustc_data_structures::unify as ut;
-use session::config::BorrowckMode;
 use std::cell::{Cell, Ref, RefCell, RefMut};
 use std::collections::BTreeMap;
 use std::fmt;
 use syntax::ast;
 use syntax_pos::symbol::InternedString;
-use syntax_pos::{self, Span};
-use traits::{self, ObligationCause, PredicateObligations, TraitEngine};
-use ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
-use ty::fold::TypeFoldable;
-use ty::relate::RelateResult;
-use ty::subst::{Kind, Substs};
-use ty::{self, GenericParamDefKind, Ty, TyCtxt, CtxtInterners};
-use ty::{FloatVid, IntVid, TyVid};
-use util::nodemap::FxHashMap;
+use syntax_pos::Span;
 
 use self::combine::CombineFields;
 use self::lexical_region_resolve::LexicalRegionResolutions;
@@ -202,7 +204,7 @@ pub struct InferCtxt<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     // for each body-id in this map, which will process the
     // obligations within. This is expected to be done 'late enough'
     // that all type inference variables have been bound and so forth.
-    pub region_obligations: RefCell<Vec<(ast::NodeId, RegionObligation<'tcx>)>>,
+    pub region_obligations: RefCell<Vec<(hir::HirId, RegionObligation<'tcx>)>>,
 
     /// What is the innermost universe we have created? Starts out as
     /// `UniverseIndex::root()` but grows from there as we enter
@@ -221,7 +223,7 @@ pub struct InferCtxt<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
 /// replaced with.
 pub type PlaceholderMap<'tcx> = BTreeMap<ty::BoundRegion, ty::Region<'tcx>>;
 
-/// See `error_reporting` module for more details
+/// See the `error_reporting` module for more details.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum ValuePairs<'tcx> {
     Types(ExpectedFound<Ty<'tcx>>),
@@ -233,7 +235,7 @@ pub enum ValuePairs<'tcx> {
 /// The trace designates the path through inference that we took to
 /// encounter an error or subtyping constraint.
 ///
-/// See `error_reporting` module for more details.
+/// See the `error_reporting` module for more details.
 #[derive(Clone)]
 pub struct TypeTrace<'tcx> {
     cause: ObligationCause<'tcx>,
@@ -454,9 +456,9 @@ impl fmt::Display for FixupError {
     }
 }
 
-/// Helper type of a temporary returned by tcx.infer_ctxt().
+/// Helper type of a temporary returned by `tcx.infer_ctxt()`.
 /// Necessary because we can't write the following bound:
-/// F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(InferCtxt<'b, 'gcx, 'tcx>).
+/// `F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(InferCtxt<'b, 'gcx, 'tcx>)`.
 pub struct InferCtxtBuilder<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     global_tcx: TyCtxt<'a, 'gcx, 'gcx>,
     arena: SyncDroplessArena,
@@ -487,7 +489,7 @@ impl<'a, 'gcx, 'tcx> InferCtxtBuilder<'a, 'gcx, 'tcx> {
     /// inference context that contains each of the bound values
     /// within instantiated as a fresh variable. The `f` closure is
     /// invoked with the new infcx, along with the instantiated value
-    /// `V` and a substitution `S`.  This substitution `S` maps from
+    /// `V` and a substitution `S`. This substitution `S` maps from
     /// the bound values in `C` to their instantiated values in `V`
     /// (in other words, `S(C) = V`).
     pub fn enter_with_canonical<T, R>(
@@ -563,7 +565,7 @@ impl<'tcx, T> InferOk<'tcx, T> {
         }
     }
 
-    /// Extract `value`, registering any obligations into `fulfill_cx`
+    /// Extracts `value`, registering any obligations into `fulfill_cx`.
     pub fn into_value_registering_obligations(
         self,
         infcx: &InferCtxt<'_, '_, 'tcx>,
@@ -617,8 +619,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn type_is_unconstrained_numeric(&'a self, ty: Ty<'_>) -> UnconstrainedNumeric {
-        use ty::error::UnconstrainedNumeric::Neither;
-        use ty::error::UnconstrainedNumeric::{UnconstrainedFloat, UnconstrainedInt};
+        use crate::ty::error::UnconstrainedNumeric::Neither;
+        use crate::ty::error::UnconstrainedNumeric::{UnconstrainedFloat, UnconstrainedInt};
         match ty.sty {
             ty::Infer(ty::IntVar(vid)) => {
                 if self.int_unification_table
@@ -794,7 +796,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             .commit(region_constraints_snapshot);
     }
 
-    /// Execute `f` and commit the bindings
+    /// Executes `f` and commit the bindings.
     pub fn commit_unconditionally<R, F>(&self, f: F) -> R
     where
         F: FnOnce() -> R,
@@ -806,7 +808,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         r
     }
 
-    /// Execute `f` and commit the bindings if closure `f` returns `Ok(_)`
+    /// Executes `f` and commit the bindings if closure `f` returns `Ok(_)`.
     pub fn commit_if_ok<T, E, F>(&self, f: F) -> Result<T, E>
     where
         F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> Result<T, E>,
@@ -838,7 +840,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         r
     }
 
-    /// Execute `f` then unroll any bindings it creates
+    /// Executes `f` then unroll any bindings it creates.
     pub fn probe<R, F>(&self, f: F) -> R
     where
         F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> R,
@@ -935,32 +937,41 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             return None;
         }
 
-        let (
-            ty::SubtypePredicate {
-                a_is_expected,
-                a,
-                b,
-            },
-            _,
-        ) = self.replace_bound_vars_with_placeholders(predicate);
+        Some(self.commit_if_ok(|snapshot| {
+            let (
+                ty::SubtypePredicate {
+                    a_is_expected,
+                    a,
+                    b,
+                },
+                placeholder_map,
+            ) = self.replace_bound_vars_with_placeholders(predicate);
 
-        Some(
-            self.at(cause, param_env)
-                .sub_exp(a_is_expected, a, b)
-                .map(|ok| ok.unit()),
-        )
+            let ok = self.at(cause, param_env)
+                .sub_exp(a_is_expected, a, b)?;
+
+            self.leak_check(false, &placeholder_map, snapshot)?;
+
+            Ok(ok.unit())
+        }))
     }
 
     pub fn region_outlives_predicate(
         &self,
         cause: &traits::ObligationCause<'tcx>,
         predicate: &ty::PolyRegionOutlivesPredicate<'tcx>,
-    ) {
-        let (ty::OutlivesPredicate(r_a, r_b), _) =
-            self.replace_bound_vars_with_placeholders(predicate);
-        let origin =
-            SubregionOrigin::from_obligation_cause(cause, || RelateRegionParamBound(cause.span));
-        self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b`
+    ) -> UnitResult<'tcx> {
+        self.commit_if_ok(|snapshot| {
+            let (ty::OutlivesPredicate(r_a, r_b), placeholder_map) =
+                self.replace_bound_vars_with_placeholders(predicate);
+            let origin = SubregionOrigin::from_obligation_cause(
+                cause,
+                || RelateRegionParamBound(cause.span),
+            );
+            self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b`
+            self.leak_check(false, &placeholder_map, snapshot)?;
+            Ok(())
+        })
     }
 
     pub fn next_ty_var_id(&self, diverging: bool, origin: TypeVariableOrigin) -> TyVid {
@@ -996,14 +1007,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         self.float_unification_table.borrow_mut().new_key(None)
     }
 
-    /// Create a fresh region variable with the next available index.
+    /// Creates a fresh region variable with the next available index.
     /// The variable will be created in the maximum universe created
     /// thus far, allowing it to name any region created thus far.
     pub fn next_region_var(&self, origin: RegionVariableOrigin) -> ty::Region<'tcx> {
         self.next_region_var_in_universe(origin, self.universe())
     }
 
-    /// Create a fresh region variable with the next available index
+    /// Creates a fresh region variable with the next available index
     /// in the given universe; typically, you can use
     /// `next_region_var` and just use the maximal universe.
     pub fn next_region_var_in_universe(
@@ -1016,6 +1027,18 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         self.tcx.mk_region(ty::ReVar(region_var))
     }
 
+    /// Return the universe that the region `r` was created in.  For
+    /// most regions (e.g., `'static`, named regions from the user,
+    /// etc) this is the root universe U0. For inference variables or
+    /// placeholders, however, it will return the universe which which
+    /// they are associated.
+    fn universe_of_region(
+        &self,
+        r: ty::Region<'tcx>,
+    ) -> ty::UniverseIndex {
+        self.borrow_region_constraints().universe(r)
+    }
+
     /// Number of region variables created so far.
     pub fn num_region_vars(&self) -> usize {
         self.borrow_region_constraints().num_region_vars()
@@ -1069,8 +1092,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         Substs::for_item(self.tcx, def_id, |param, _| self.var_for_def(span, param))
     }
 
-    /// True if errors have been reported since this infcx was
-    /// created.  This is sometimes used as a heuristic to skip
+    /// Returns `true` if errors have been reported since this infcx was
+    /// created. This is sometimes used as a heuristic to skip
     /// reporting errors that often occur as a result of earlier
     /// errors, but where it's hard to be 100% sure (e.g., unresolved
     /// inference variables, regionck errors).
@@ -1278,7 +1301,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         value.fold_with(&mut r)
     }
 
-    /// Returns true if `T` contains unresolved type variables. In the
+    /// Returns `true` if `T` contains unresolved type variables. In the
     /// process of visiting `T`, this will resolve (where possible)
     /// type variables in `T`, but it never constructs the final,
     /// resolved type, so it's more efficient than
@@ -1291,14 +1314,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         value.visit_with(&mut r)
     }
 
-    pub fn resolve_type_and_region_vars_if_possible<T>(&self, value: &T) -> T
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        let mut r = resolve::OpportunisticTypeAndRegionResolver::new(self);
-        value.fold_with(&mut r)
-    }
-
     pub fn fully_resolve<T: TypeFoldable<'tcx>>(&self, value: &T) -> FixupResult<T> {
         /*!
          * Attempts to resolve all type/region variables in
@@ -1369,7 +1384,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         self.tcx.replace_bound_vars(value, fld_r, fld_t)
     }
 
-    /// See `verify_generic_bound` method in `region_constraints`
+    /// See the [`region_constraints::verify_generic_bound`] method.
     pub fn verify_generic_bound(
         &self,
         origin: SubregionOrigin<'tcx>,
@@ -1421,7 +1436,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         closure_kind_ty.to_opt_closure_kind()
     }
 
-    /// Obtain the signature of a closure.  For closures, unlike
+    /// Obtain the signature of a closure. For closures, unlike
     /// `tcx.fn_sig(def_id)`, this method will work during the
     /// type-checking of the enclosing function and return the closure
     /// signature in its partially inferred state.
@@ -1440,7 +1455,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn partially_normalize_associated_types_in<T>(
         &self,
         span: Span,
-        body_id: ast::NodeId,
+        body_id: hir::HirId,
         param_env: ty::ParamEnv<'tcx>,
         value: &T,
     ) -> InferOk<'tcx, T>
@@ -1466,8 +1481,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 
     /// Clears the selection, evaluation, and projection caches. This is useful when
-    /// repeatedly attempting to select an Obligation while changing only
-    /// its ParamEnv, since FulfillmentContext doesn't use 'probe'
+    /// repeatedly attempting to select an `Obligation` while changing only
+    /// its `ParamEnv`, since `FulfillmentContext` doesn't use probing.
     pub fn clear_caches(&self) {
         self.selection_cache.clear();
         self.evaluation_cache.clear();
@@ -1478,7 +1493,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         self.universe.get()
     }
 
-    /// Create and return a fresh universe that extends all previous
+    /// Creates and return a fresh universe that extends all previous
     /// universes. Updates `self.universe` to that new universe.
     pub fn create_next_universe(&self) -> ty::UniverseIndex {
         let u = self.universe.get().next_universe();
diff --git a/src/librustc/infer/nll_relate/mod.rs b/src/librustc/infer/nll_relate/mod.rs
index 7671a47135702..f37e24b292e03 100644
--- a/src/librustc/infer/nll_relate/mod.rs
+++ b/src/librustc/infer/nll_relate/mod.rs
@@ -47,17 +47,17 @@ where
 
     /// How are we relating `a` and `b`?
     ///
-    /// - covariant means `a <: b`
-    /// - contravariant means `b <: a`
-    /// - invariant means `a == b
-    /// - bivariant means that it doesn't matter
+    /// - Covariant means `a <: b`.
+    /// - Contravariant means `b <: a`.
+    /// - Invariant means `a == b.
+    /// - Bivariant means that it doesn't matter.
     ambient_variance: ty::Variance,
 
     /// When we pass through a set of binders (e.g., when looking into
-    /// a `fn` type), we push a new bound region scope onto here.  This
+    /// a `fn` type), we push a new bound region scope onto here. This
     /// will contain the instantiated region for each region in those
     /// binders. When we then encounter a `ReLateBound(d, br)`, we can
-    /// use the debruijn index `d` to find the right scope, and then
+    /// use the De Bruijn index `d` to find the right scope, and then
     /// bound region name `br` to find the specific instantiation from
     /// within that scope. See `replace_bound_region`.
     ///
@@ -114,7 +114,7 @@ pub trait TypeRelatingDelegate<'tcx> {
     /// Define the normalization strategy to use, eager or lazy.
     fn normalization() -> NormalizationStrategy;
 
-    /// Enable some optimizations if we do not expect inference variables
+    /// Enables some optimizations if we do not expect inference variables
     /// in the RHS of the relation.
     fn forbid_inference_vars() -> bool;
 }
@@ -208,7 +208,7 @@ where
     /// When we encounter binders during the type traversal, we record
     /// the value to substitute for each of the things contained in
     /// that binder. (This will be either a universal placeholder or
-    /// an existential inference variable.) Given the debruijn index
+    /// an existential inference variable.) Given the De Bruijn index
     /// `debruijn` (and name `br`) of some binder we have now
     /// encountered, this routine finds the value that we instantiated
     /// the region with; to do so, it indexes backwards into the list
diff --git a/src/librustc/infer/opaque_types/mod.rs b/src/librustc/infer/opaque_types/mod.rs
index 5e94bb1f877fb..e75446b01c11e 100644
--- a/src/librustc/infer/opaque_types/mod.rs
+++ b/src/librustc/infer/opaque_types/mod.rs
@@ -1,16 +1,16 @@
-use hir::def_id::DefId;
-use hir;
-use hir::Node;
-use infer::{self, InferCtxt, InferOk, TypeVariableOrigin};
-use infer::outlives::free_region_map::FreeRegionRelations;
+use crate::hir::def_id::DefId;
+use crate::hir;
+use crate::hir::Node;
+use crate::infer::{self, InferCtxt, InferOk, TypeVariableOrigin};
+use crate::infer::outlives::free_region_map::FreeRegionRelations;
 use rustc_data_structures::fx::FxHashMap;
 use syntax::ast;
-use traits::{self, PredicateObligation};
-use ty::{self, Ty, TyCtxt, GenericParamDefKind};
-use ty::fold::{BottomUpFolder, TypeFoldable, TypeFolder};
-use ty::outlives::Component;
-use ty::subst::{Kind, Substs, UnpackedKind};
-use util::nodemap::DefIdMap;
+use crate::traits::{self, PredicateObligation};
+use crate::ty::{self, Ty, TyCtxt, GenericParamDefKind};
+use crate::ty::fold::{BottomUpFolder, TypeFoldable, TypeFolder};
+use crate::ty::outlives::Component;
+use crate::ty::subst::{Kind, Substs, UnpackedKind};
+use crate::util::nodemap::DefIdMap;
 
 pub type OpaqueTypeMap<'tcx> = DefIdMap<OpaqueTypeDecl<'tcx>>;
 
@@ -26,7 +26,7 @@ pub struct OpaqueTypeDecl<'tcx> {
     ///
     /// winds up desugared to:
     ///
-    ///     abstract type Foo<'x, T>: Trait<'x>
+    ///     abstract type Foo<'x, X>: Trait<'x>
     ///     fn foo<'a, 'b, T>() -> Foo<'a, T>
     ///
     /// then `substs` would be `['a, T]`.
@@ -46,7 +46,7 @@ pub struct OpaqueTypeDecl<'tcx> {
     /// lifetime parameter on `foo`.)
     pub concrete_ty: Ty<'tcx>,
 
-    /// True if the `impl Trait` bounds include region bounds.
+    /// Returns `true` if the `impl Trait` bounds include region bounds.
     /// For example, this would be true for:
     ///
     ///     fn foo<'a, 'b, 'c>() -> impl Trait<'c> + 'a + 'b
@@ -71,7 +71,7 @@ pub struct OpaqueTypeDecl<'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
-    /// Replace all opaque types in `value` with fresh inference variables
+    /// Replaces all opaque types in `value` with fresh inference variables
     /// and creates appropriate obligations. For example, given the input:
     ///
     ///     impl Iterator<Item = impl Debug>
@@ -88,7 +88,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     ///
     /// # Parameters
     ///
-    /// - `parent_def_id` -- the def-id of the function in which the opaque type
+    /// - `parent_def_id` -- the `DefId` of the function in which the opaque type
     ///   is defined
     /// - `body_id` -- the body-id with which the resulting obligations should
     ///   be associated
@@ -98,7 +98,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     pub fn instantiate_opaque_types<T: TypeFoldable<'tcx>>(
         &self,
         parent_def_id: DefId,
-        body_id: ast::NodeId,
+        body_id: hir::HirId,
         param_env: ty::ParamEnv<'tcx>,
         value: &T,
     ) -> InferOk<'tcx, (T, OpaqueTypeMap<'tcx>)> {
@@ -132,7 +132,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     ///
     /// # The Problem
     ///
-    /// Let's work through an example to explain how it works.  Assume
+    /// Let's work through an example to explain how it works. Assume
     /// the current function is as follows:
     ///
     /// ```text
@@ -164,7 +164,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     /// replace each of the references (`Foo1<'a>`, `Foo2<'b>`) with
     /// fresh inference variables C1 and C2. We wish to use the values
     /// of these variables to infer the underlying types of `Foo1` and
-    /// `Foo2`.  That is, this gives rise to higher-order (pattern) unification
+    /// `Foo2`. That is, this gives rise to higher-order (pattern) unification
     /// constraints like:
     ///
     /// ```text
@@ -199,7 +199,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     ///
     /// Ordinarily, the subtyping rules would ensure that these are
     /// sufficiently large. But since `impl Bar<'a>` isn't a specific
-    /// type per se, we don't get such constraints by default.  This
+    /// type per se, we don't get such constraints by default. This
     /// is where this function comes into play. It adds extra
     /// constraints to ensure that all the regions which appear in the
     /// inferred type are regions that could validly appear.
@@ -632,7 +632,7 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for ReverseMapper<'cx, 'gcx, 'tcx>
 struct Instantiator<'a, 'gcx: 'tcx, 'tcx: 'a> {
     infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
     parent_def_id: DefId,
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
     param_env: ty::ParamEnv<'tcx>,
     opaque_types: OpaqueTypeMap<'tcx>,
     obligations: Vec<PredicateObligation<'tcx>>,
@@ -813,7 +813,7 @@ impl<'a, 'gcx, 'tcx> Instantiator<'a, 'gcx, 'tcx> {
     }
 }
 
-/// Whether `opaque_node_id` is a sibling or a child of a sibling of `def_id`
+/// Returns `true` if `opaque_node_id` is a sibling or a child of a sibling of `def_id`.
 ///
 /// ```rust
 /// pub mod foo {
@@ -827,11 +827,10 @@ impl<'a, 'gcx, 'tcx> Instantiator<'a, 'gcx, 'tcx> {
 /// }
 /// ```
 ///
-/// Here, `def_id` will be the `DefId` of the existential type `Baz`.
-/// `opaque_node_id` is the `NodeId` of the reference to Baz --
-///  so either the return type of f1 or f2.
-/// We will return true if the reference is within the same module as the existential type
-/// So true for f1, false for f2.
+/// Here, `def_id` is the `DefId` of the existential type `Baz` and `opaque_node_id` is the
+/// `NodeId` of the reference to `Baz` (i.e., the return type of both `f1` and `f2`).
+/// We return `true` if the reference is within the same module as the existential type
+/// (i.e., `true` for `f1`, `false` for `f2`).
 pub fn may_define_existential_type(
     tcx: TyCtxt<'_, '_, '_>,
     def_id: DefId,
diff --git a/src/librustc/infer/outlives/env.rs b/src/librustc/infer/outlives/env.rs
index 677b6136ea03b..39aa51a95f793 100644
--- a/src/librustc/infer/outlives/env.rs
+++ b/src/librustc/infer/outlives/env.rs
@@ -1,10 +1,10 @@
-use infer::outlives::free_region_map::FreeRegionMap;
-use infer::{GenericKind, InferCtxt};
+use crate::infer::outlives::free_region_map::FreeRegionMap;
+use crate::infer::{GenericKind, InferCtxt};
+use crate::hir;
 use rustc_data_structures::fx::FxHashMap;
-use syntax::ast;
 use syntax_pos::Span;
-use traits::query::outlives_bounds::{self, OutlivesBound};
-use ty::{self, Ty};
+use crate::traits::query::outlives_bounds::{self, OutlivesBound};
+use crate::ty::{self, Ty};
 
 /// The `OutlivesEnvironment` collects information about what outlives
 /// what in a given type-checking setting. For example, if we have a
@@ -55,7 +55,7 @@ pub struct OutlivesEnvironment<'tcx> {
     // results when proving outlives obligations like `T: 'x` later
     // (e.g., if `T: 'x` must be proven within the body B1, then we
     // know it is true if either `'a: 'x` or `'b: 'x`).
-    region_bound_pairs_map: FxHashMap<ast::NodeId, RegionBoundPairs<'tcx>>,
+    region_bound_pairs_map: FxHashMap<hir::HirId, RegionBoundPairs<'tcx>>,
 
     // Used to compute `region_bound_pairs_map`: contains the set of
     // in-scope region-bound pairs thus far.
@@ -63,7 +63,7 @@ pub struct OutlivesEnvironment<'tcx> {
 }
 
 /// "Region-bound pairs" tracks outlives relations that are known to
-/// be true, either because of explicit where clauses like `T: 'a` or
+/// be true, either because of explicit where-clauses like `T: 'a` or
 /// because of implied bounds.
 pub type RegionBoundPairs<'tcx> = Vec<(ty::Region<'tcx>, GenericKind<'tcx>)>;
 
@@ -87,7 +87,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
     }
 
     /// Borrows current value of the `region_bound_pairs`.
-    pub fn region_bound_pairs_map(&self) -> &FxHashMap<ast::NodeId, RegionBoundPairs<'tcx>> {
+    pub fn region_bound_pairs_map(&self) -> &FxHashMap<hir::HirId, RegionBoundPairs<'tcx>> {
         &self.region_bound_pairs_map
     }
 
@@ -162,7 +162,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
         &mut self,
         infcx: &InferCtxt<'a, 'gcx, 'tcx>,
         fn_sig_tys: &[Ty<'tcx>],
-        body_id: ast::NodeId,
+        body_id: hir::HirId,
         span: Span,
     ) {
         debug!("add_implied_bounds()");
@@ -176,7 +176,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> OutlivesEnvironment<'tcx> {
     }
 
     /// Save the current set of region-bound pairs under the given `body_id`.
-    pub fn save_implied_bounds(&mut self, body_id: ast::NodeId) {
+    pub fn save_implied_bounds(&mut self, body_id: hir::HirId) {
         let old = self.region_bound_pairs_map.insert(
             body_id,
             self.region_bound_pairs_accum.clone(),
diff --git a/src/librustc/infer/outlives/free_region_map.rs b/src/librustc/infer/outlives/free_region_map.rs
index a6703c9d679da..78353e52ad462 100644
--- a/src/librustc/infer/outlives/free_region_map.rs
+++ b/src/librustc/infer/outlives/free_region_map.rs
@@ -1,4 +1,4 @@
-use ty::{self, Lift, TyCtxt, Region};
+use crate::ty::{self, Lift, TyCtxt, Region};
 use rustc_data_structures::transitive_relation::TransitiveRelation;
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
@@ -24,7 +24,7 @@ impl<'tcx> FreeRegionMap<'tcx> {
         }
     }
 
-    /// Compute the least-upper-bound of two free regions. In some
+    /// Computes the least-upper-bound of two free regions. In some
     /// cases, this is more conservative than necessary, in order to
     /// avoid making arbitrary choices. See
     /// `TransitiveRelation::postdom_upper_bound` for more details.
diff --git a/src/librustc/infer/outlives/obligations.rs b/src/librustc/infer/outlives/obligations.rs
index abe835c9211a5..bbda3d2fdbf84 100644
--- a/src/librustc/infer/outlives/obligations.rs
+++ b/src/librustc/infer/outlives/obligations.rs
@@ -55,18 +55,18 @@
 //! fn foo<U, F: for<'a> FnMut(&'a U)>(_f: F) {}
 //! ```
 //!
-//! the type of the closure's first argument would be `&'a ?U`.  We
+//! the type of the closure's first argument would be `&'a ?U`. We
 //! might later infer `?U` to something like `&'b u32`, which would
 //! imply that `'b: 'a`.
 
-use infer::outlives::env::RegionBoundPairs;
-use infer::outlives::verify::VerifyBoundCx;
-use infer::{self, GenericKind, InferCtxt, RegionObligation, SubregionOrigin, VerifyBound};
+use crate::infer::outlives::env::RegionBoundPairs;
+use crate::infer::outlives::verify::VerifyBoundCx;
+use crate::infer::{self, GenericKind, InferCtxt, RegionObligation, SubregionOrigin, VerifyBound};
 use rustc_data_structures::fx::FxHashMap;
-use syntax::ast;
-use traits::ObligationCause;
-use ty::outlives::Component;
-use ty::{self, Region, Ty, TyCtxt, TypeFoldable};
+use crate::hir;
+use crate::traits::ObligationCause;
+use crate::ty::outlives::Component;
+use crate::ty::{self, Region, Ty, TyCtxt, TypeFoldable};
 
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// Registers that the given region obligation must be resolved
@@ -76,7 +76,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// information).
     pub fn register_region_obligation(
         &self,
-        body_id: ast::NodeId,
+        body_id: hir::HirId,
         obligation: RegionObligation<'tcx>,
     ) {
         debug!(
@@ -110,7 +110,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     }
 
     /// Trait queries just want to pass back type obligations "as is"
-    pub fn take_registered_region_obligations(&self) -> Vec<(ast::NodeId, RegionObligation<'tcx>)> {
+    pub fn take_registered_region_obligations(&self) -> Vec<(hir::HirId, RegionObligation<'tcx>)> {
         ::std::mem::replace(&mut *self.region_obligations.borrow_mut(), vec![])
     }
 
@@ -149,7 +149,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// processed.
     pub fn process_registered_region_obligations(
         &self,
-        region_bound_pairs_map: &FxHashMap<ast::NodeId, RegionBoundPairs<'tcx>>,
+        region_bound_pairs_map: &FxHashMap<hir::HirId, RegionBoundPairs<'tcx>>,
         implicit_region_bound: Option<ty::Region<'tcx>>,
         param_env: ty::ParamEnv<'tcx>,
     ) {
diff --git a/src/librustc/infer/outlives/verify.rs b/src/librustc/infer/outlives/verify.rs
index 4e9a8e9ded899..494f708c6a7b7 100644
--- a/src/librustc/infer/outlives/verify.rs
+++ b/src/librustc/infer/outlives/verify.rs
@@ -1,10 +1,10 @@
-use hir::def_id::DefId;
-use infer::outlives::env::RegionBoundPairs;
-use infer::{GenericKind, VerifyBound};
-use traits;
-use ty::subst::{Subst, Substs};
-use ty::{self, Ty, TyCtxt};
-use util::captures::Captures;
+use crate::hir::def_id::DefId;
+use crate::infer::outlives::env::RegionBoundPairs;
+use crate::infer::{GenericKind, VerifyBound};
+use crate::traits;
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::{self, Ty, TyCtxt};
+use crate::util::captures::Captures;
 
 /// The `TypeOutlives` struct has the job of "lowering" a `T: 'a`
 /// obligation into a series of `'a: 'b` constraints and "verifys", as
@@ -74,7 +74,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
     /// This is an "approximate" check -- it may not find all
     /// applicable bounds, and not all the bounds it returns can be
     /// relied upon. In particular, this check ignores region
-    /// identity.  So, for example, if we have `<T as
+    /// identity. So, for example, if we have `<T as
     /// Trait<'0>>::Item` where `'0` is a region variable, and the
     /// user has `<T as Trait<'a>>::Item: 'b` in the environment, then
     /// the clause from the environment only applies if `'0 = 'a`,
@@ -96,7 +96,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
         })
     }
 
-    /// Searches the where clauses in scope for regions that
+    /// Searches the where-clauses in scope for regions that
     /// `projection_ty` is known to outlive. Currently requires an
     /// exact match.
     pub fn projection_declared_bounds_from_trait(
@@ -251,7 +251,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
             .map(move |r| r.subst(tcx, projection_ty.substs))
     }
 
-    /// Given the def-id of an associated item, returns any region
+    /// Given the `DefId` of an associated item, returns any region
     /// bounds attached to that associated item from the trait definition.
     ///
     /// For example:
@@ -262,7 +262,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
     /// }
     /// ```
     ///
-    /// If we were given the def-id of `Foo::Bar`, we would return
+    /// If we were given the `DefId` of `Foo::Bar`, we would return
     /// `'a`. You could then apply the substitutions from the
     /// projection to convert this into your namespace. This also
     /// works if the user writes `where <Self as Foo<'a>>::Bar: 'a` on
diff --git a/src/librustc/infer/region_constraints/README.md b/src/librustc/infer/region_constraints/README.md
index 775bbf955b830..ea7fffe9dc1c6 100644
--- a/src/librustc/infer/region_constraints/README.md
+++ b/src/librustc/infer/region_constraints/README.md
@@ -1,77 +1,3 @@
-# Region constraint collection
-
-> WARNING: This README is obsolete and will be removed soon! For
-> more info on how the current borrowck works, see the [rustc guide].
+For info on how the current borrowck works, see the [rustc guide].
 
 [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/borrowck.html
-
-## Terminology
-
-Note that we use the terms region and lifetime interchangeably.
-
-## Introduction
-
-As described in the rustc guide [chapter on type inference][ti], and unlike
-normal type inference, which is similar in spirit to H-M and thus
-works progressively, the region type inference works by accumulating
-constraints over the course of a function.  Finally, at the end of
-processing a function, we process and solve the constraints all at
-once.
-
-[ti]: https://rust-lang.github.io/rustc-guide/type-inference.html
-
-The constraints are always of one of three possible forms:
-
-- `ConstrainVarSubVar(Ri, Rj)` states that region variable Ri must be
-  a subregion of Rj
-- `ConstrainRegSubVar(R, Ri)` states that the concrete region R (which
-  must not be a variable) must be a subregion of the variable Ri
-- `ConstrainVarSubReg(Ri, R)` states the variable Ri should be less
-  than the concrete region R. This is kind of deprecated and ought to
-  be replaced with a verify (they essentially play the same role).
-
-In addition to constraints, we also gather up a set of "verifys"
-(what, you don't think Verify is a noun? Get used to it my
-friend!). These represent relations that must hold but which don't
-influence inference proper. These take the form of:
-
-- `VerifyRegSubReg(Ri, Rj)` indicates that Ri <= Rj must hold,
-  where Rj is not an inference variable (and Ri may or may not contain
-  one). This doesn't influence inference because we will already have
-  inferred Ri to be as small as possible, so then we just test whether
-  that result was less than Rj or not.
-- `VerifyGenericBound(R, Vb)` is a more complex expression which tests
-  that the region R must satisfy the bound `Vb`. The bounds themselves
-  may have structure like "must outlive one of the following regions"
-  or "must outlive ALL of the following regions. These bounds arise
-  from constraints like `T: 'a` -- if we know that `T: 'b` and `T: 'c`
-  (say, from where clauses), then we can conclude that `T: 'a` if `'b:
-  'a` *or* `'c: 'a`.
-
-## Building up the constraints
-
-Variables and constraints are created using the following methods:
-
-- `new_region_var()` creates a new, unconstrained region variable;
-- `make_subregion(Ri, Rj)` states that Ri is a subregion of Rj
-- `lub_regions(Ri, Rj) -> Rk` returns a region Rk which is
-  the smallest region that is greater than both Ri and Rj
-- `glb_regions(Ri, Rj) -> Rk` returns a region Rk which is
-  the greatest region that is smaller than both Ri and Rj
-
-The actual region resolution algorithm is not entirely
-obvious, though it is also not overly complex.
-
-## Snapshotting
-
-It is also permitted to try (and rollback) changes to the graph.  This
-is done by invoking `start_snapshot()`, which returns a value.  Then
-later you can call `rollback_to()` which undoes the work.
-Alternatively, you can call `commit()` which ends all snapshots.
-Snapshots can be recursive---so you can start a snapshot when another
-is in progress, but only the root snapshot can "commit".
-
-## Skolemization
-
-For a discussion on skolemization and higher-ranked subtyping, please
-see the module `middle::infer::higher_ranked::doc`.
diff --git a/src/librustc/infer/region_constraints/leak_check.rs b/src/librustc/infer/region_constraints/leak_check.rs
new file mode 100644
index 0000000000000..8085258610d84
--- /dev/null
+++ b/src/librustc/infer/region_constraints/leak_check.rs
@@ -0,0 +1,174 @@
+use super::*;
+use crate::infer::{CombinedSnapshot, PlaceholderMap};
+use crate::ty::error::TypeError;
+use crate::ty::relate::RelateResult;
+
+impl<'tcx> RegionConstraintCollector<'tcx> {
+    /// Searches region constraints created since `snapshot` that
+    /// affect one of the placeholders in `placeholder_map`, returning
+    /// an error if any of the placeholders are related to another
+    /// placeholder or would have to escape into some parent universe
+    /// that cannot name them.
+    ///
+    /// This is a temporary backwards compatibility measure to try and
+    /// retain the older (arguably incorrect) behavior of the
+    /// compiler.
+    ///
+    /// NB. The use of snapshot here is mostly an efficiency thing --
+    /// we could search *all* region constraints, but that'd be a
+    /// bigger set and the data structures are not setup for that. If
+    /// we wind up keeping some form of this check long term, it would
+    /// probably be better to remove the snapshot parameter and to
+    /// refactor the constraint set.
+    pub fn leak_check(
+        &mut self,
+        tcx: TyCtxt<'_, '_, 'tcx>,
+        overly_polymorphic: bool,
+        placeholder_map: &PlaceholderMap<'tcx>,
+        _snapshot: &CombinedSnapshot<'_, 'tcx>,
+    ) -> RelateResult<'tcx, ()> {
+        debug!("leak_check(placeholders={:?})", placeholder_map);
+
+        assert!(self.in_snapshot());
+
+        // If the user gave `-Zno-leak-check`, then skip the leak
+        // check completely. This is wildly unsound and also not
+        // unlikely to cause an ICE or two. It is intended for use
+        // only during a transition period, in which the MIR typeck
+        // uses the "universe-style" check, and the rest of typeck
+        // uses the more conservative leak check.  Since the leak
+        // check is more conservative, we can't test the
+        // universe-style check without disabling it.
+        if tcx.sess.opts.debugging_opts.no_leak_check {
+            return Ok(());
+        }
+
+        // Go through each placeholder that we created.
+        for (_, &placeholder_region) in placeholder_map {
+            // Find the universe this placeholder inhabits.
+            let placeholder = match placeholder_region {
+                ty::RePlaceholder(p) => p,
+                _ => bug!(
+                    "leak_check: expected placeholder found {:?}",
+                    placeholder_region,
+                ),
+            };
+
+            // Find all regions that are related to this placeholder
+            // in some way. This means any region that either outlives
+            // or is outlived by a placeholder.
+            let mut taint_set = TaintSet::new(
+                TaintDirections::both(),
+                placeholder_region,
+            );
+            taint_set.fixed_point(tcx, &self.undo_log, &self.data.verifys);
+            let tainted_regions = taint_set.into_set();
+
+            // Report an error if two placeholders in the same universe
+            // are related to one another, or if a placeholder is related
+            // to something from a parent universe.
+            for &tainted_region in &tainted_regions {
+                if let ty::RePlaceholder(_) = tainted_region {
+                    // Two placeholders cannot be related:
+                    if tainted_region == placeholder_region {
+                        continue;
+                    }
+                } else if self.universe(tainted_region).can_name(placeholder.universe) {
+                    continue;
+                }
+
+                return Err(if overly_polymorphic {
+                    debug!("Overly polymorphic!");
+                    TypeError::RegionsOverlyPolymorphic(placeholder.name, tainted_region)
+                } else {
+                    debug!("Not as polymorphic!");
+                    TypeError::RegionsInsufficientlyPolymorphic(placeholder.name, tainted_region)
+                });
+            }
+        }
+
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+struct TaintSet<'tcx> {
+    directions: TaintDirections,
+    regions: FxHashSet<ty::Region<'tcx>>,
+}
+
+impl<'tcx> TaintSet<'tcx> {
+    fn new(directions: TaintDirections, initial_region: ty::Region<'tcx>) -> Self {
+        let mut regions = FxHashSet::default();
+        regions.insert(initial_region);
+        TaintSet {
+            directions: directions,
+            regions: regions,
+        }
+    }
+
+    fn fixed_point(
+        &mut self,
+        tcx: TyCtxt<'_, '_, 'tcx>,
+        undo_log: &[UndoLog<'tcx>],
+        verifys: &[Verify<'tcx>],
+    ) {
+        let mut prev_len = 0;
+        while prev_len < self.len() {
+            debug!(
+                "tainted: prev_len = {:?} new_len = {:?}",
+                prev_len,
+                self.len()
+            );
+
+            prev_len = self.len();
+
+            for undo_entry in undo_log {
+                match undo_entry {
+                    &AddConstraint(Constraint::VarSubVar(a, b)) => {
+                        self.add_edge(tcx.mk_region(ReVar(a)), tcx.mk_region(ReVar(b)));
+                    }
+                    &AddConstraint(Constraint::RegSubVar(a, b)) => {
+                        self.add_edge(a, tcx.mk_region(ReVar(b)));
+                    }
+                    &AddConstraint(Constraint::VarSubReg(a, b)) => {
+                        self.add_edge(tcx.mk_region(ReVar(a)), b);
+                    }
+                    &AddConstraint(Constraint::RegSubReg(a, b)) => {
+                        self.add_edge(a, b);
+                    }
+                    &AddGiven(a, b) => {
+                        self.add_edge(a, tcx.mk_region(ReVar(b)));
+                    }
+                    &AddVerify(i) => span_bug!(
+                        verifys[i].origin.span(),
+                        "we never add verifications while doing higher-ranked things",
+                    ),
+                    &Purged | &AddCombination(..) | &AddVar(..) => {}
+                }
+            }
+        }
+    }
+
+    fn into_set(self) -> FxHashSet<ty::Region<'tcx>> {
+        self.regions
+    }
+
+    fn len(&self) -> usize {
+        self.regions.len()
+    }
+
+    fn add_edge(&mut self, source: ty::Region<'tcx>, target: ty::Region<'tcx>) {
+        if self.directions.incoming {
+            if self.regions.contains(&target) {
+                self.regions.insert(source);
+            }
+        }
+
+        if self.directions.outgoing {
+            if self.regions.contains(&source) {
+                self.regions.insert(target);
+            }
+        }
+    }
+}
diff --git a/src/librustc/infer/region_constraints/mod.rs b/src/librustc/infer/region_constraints/mod.rs
index 56ae850226c91..8389f0ab1aa79 100644
--- a/src/librustc/infer/region_constraints/mod.rs
+++ b/src/librustc/infer/region_constraints/mod.rs
@@ -1,4 +1,4 @@
-//! See README.md
+//! See `README.md`.
 
 use self::CombineMapType::*;
 use self::UndoLog::*;
@@ -9,14 +9,16 @@ use super::{MiscVariable, RegionVariableOrigin, SubregionOrigin};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::unify as ut;
-use ty::ReStatic;
-use ty::{self, Ty, TyCtxt};
-use ty::{BrFresh, ReLateBound, ReVar};
-use ty::{Region, RegionVid};
+use crate::ty::ReStatic;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::{BrFresh, ReLateBound, ReVar};
+use crate::ty::{Region, RegionVid};
 
 use std::collections::BTreeMap;
 use std::{cmp, fmt, mem, u32};
 
+mod leak_check;
+
 #[derive(Default)]
 pub struct RegionConstraintCollector<'tcx> {
     /// For each `RegionVid`, the corresponding `RegionVariableOrigin`.
@@ -108,16 +110,16 @@ pub struct RegionConstraintData<'tcx> {
     pub givens: FxHashSet<(Region<'tcx>, ty::RegionVid)>,
 }
 
-/// A constraint that influences the inference process.
+/// Represents a constraint that influences the inference process.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, PartialOrd, Ord)]
 pub enum Constraint<'tcx> {
-    /// One region variable is subregion of another
+    /// A region variable is a subregion of another.
     VarSubVar(RegionVid, RegionVid),
 
-    /// Concrete region is subregion of region variable
+    /// A concrete region is a subregion of region variable.
     RegSubVar(Region<'tcx>, RegionVid),
 
-    /// Region variable is subregion of concrete region. This does not
+    /// A region variable is a subregion of a concrete region. This does not
     /// directly affect inference, but instead is checked after
     /// inference is complete.
     VarSubReg(RegionVid, Region<'tcx>),
@@ -138,9 +140,9 @@ impl Constraint<'_> {
     }
 }
 
-/// VerifyGenericBound(T, _, R, RS): The parameter type `T` (or
+/// `VerifyGenericBound(T, _, R, RS)`: the parameter type `T` (or
 /// associated type) must outlive the region `R`. `T` is known to
-/// outlive `RS`. Therefore verify that `R <= RS[i]` for some
+/// outlive `RS`. Therefore, verify that `R <= RS[i]` for some
 /// `i`. Inference variables may be involved (but this verification
 /// step doesn't influence inference).
 #[derive(Debug, Clone)]
@@ -164,7 +166,7 @@ EnumTypeFoldableImpl! {
     }
 }
 
-/// Describes the things that some `GenericKind` value G is known to
+/// Describes the things that some `GenericKind` value `G` is known to
 /// outlive. Each variant of `VerifyBound` can be thought of as a
 /// function:
 ///
@@ -187,13 +189,15 @@ pub enum VerifyBound<'tcx> {
     /// following, where `G` is the generic for which this verify
     /// bound was created:
     ///
-    ///     fn(min) -> bool {
-    ///       if G == K {
+    /// ```rust
+    /// fn(min) -> bool {
+    ///     if G == K {
     ///         B(min)
-    ///       } else {
+    ///     } else {
     ///         false
-    ///       }
     ///     }
+    /// }
+    /// ```
     ///
     /// In other words, if the generic `G` that we are checking is
     /// equal to `K`, then check the associated verify bound
@@ -202,14 +206,16 @@ pub enum VerifyBound<'tcx> {
     /// This is used when we have something in the environment that
     /// may or may not be relevant, depending on the region inference
     /// results. For example, we may have `where <T as
-    /// Trait<'a>>::Item: 'b` in our where clauses. If we are
+    /// Trait<'a>>::Item: 'b` in our where-clauses. If we are
     /// generating the verify-bound for `<T as Trait<'0>>::Item`, then
     /// this where-clause is only relevant if `'0` winds up inferred
     /// to `'a`.
     ///
     /// So we would compile to a verify-bound like
     ///
-    ///     IfEq(<T as Trait<'a>>::Item, AnyRegion('a))
+    /// ```
+    /// IfEq(<T as Trait<'a>>::Item, AnyRegion('a))
+    /// ```
     ///
     /// meaning, if the subject G is equal to `<T as Trait<'a>>::Item`
     /// (after inference), and `'a: min`, then `G: min`.
@@ -217,9 +223,11 @@ pub enum VerifyBound<'tcx> {
 
     /// Given a region `R`, expands to the function:
     ///
-    ///     fn(min) -> bool {
-    ///       R: min
-    ///     }
+    /// ```
+    /// fn(min) -> bool {
+    ///     R: min
+    /// }
+    /// ```
     ///
     /// This is used when we can establish that `G: R` -- therefore,
     /// if `R: min`, then by transitivity `G: min`.
@@ -227,20 +235,23 @@ pub enum VerifyBound<'tcx> {
 
     /// Given a set of bounds `B`, expands to the function:
     ///
-    ///     fn(min) -> bool {
-    ///       exists (b in B) { b(min) }
-    ///     }
+    /// ```rust
+    /// fn(min) -> bool {
+    ///     exists (b in B) { b(min) }
+    /// }
+    /// ```
     ///
     /// In other words, if we meet some bound in `B`, that suffices.
-    /// This is used when all the bounds in `B` are known to apply to
-    /// G.
+    /// This is used when all the bounds in `B` are known to apply to `G`.
     AnyBound(Vec<VerifyBound<'tcx>>),
 
     /// Given a set of bounds `B`, expands to the function:
     ///
-    ///     fn(min) -> bool {
-    ///       forall (b in B) { b(min) }
-    ///     }
+    /// ```rust
+    /// fn(min) -> bool {
+    ///     forall (b in B) { b(min) }
+    /// }
+    /// ```
     ///
     /// In other words, if we meet *all* bounds in `B`, that suffices.
     /// This is used when *some* bound in `B` is known to suffice, but
@@ -256,19 +267,19 @@ struct TwoRegions<'tcx> {
 
 #[derive(Copy, Clone, PartialEq)]
 enum UndoLog<'tcx> {
-    /// We added `RegionVid`
+    /// We added `RegionVid`.
     AddVar(RegionVid),
 
-    /// We added the given `constraint`
+    /// We added the given `constraint`.
     AddConstraint(Constraint<'tcx>),
 
-    /// We added the given `verify`
+    /// We added the given `verify`.
     AddVerify(usize),
 
-    /// We added the given `given`
+    /// We added the given `given`.
     AddGiven(Region<'tcx>, ty::RegionVid),
 
-    /// We added a GLB/LUB "combination variable"
+    /// We added a GLB/LUB "combination variable".
     AddCombination(CombineMapType, TwoRegions<'tcx>),
 
     /// During skolemization, we sometimes purge entries from the undo
@@ -303,7 +314,7 @@ pub struct RegionSnapshot {
 /// When working with placeholder regions, we often wish to find all of
 /// the regions that are either reachable from a placeholder region, or
 /// which can reach a placeholder region, or both. We call such regions
-/// *tainted* regions.  This struct allows you to decide what set of
+/// *tainted* regions. This struct allows you to decide what set of
 /// tainted regions you want.
 #[derive(Debug)]
 pub struct TaintDirections {
@@ -359,7 +370,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
 
     /// Takes (and clears) the current set of constraints. Note that
     /// the set of variables remains intact, but all relationships
-    /// between them are reset.  This is used during NLL checking to
+    /// between them are reset. This is used during NLL checking to
     /// grab the set of constraints that arose from a particular
     /// operation.
     ///
@@ -505,8 +516,8 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
             self.undo_log.push(AddVar(vid));
         }
         debug!(
-            "created new region variable {:?} with origin {:?}",
-            vid, origin
+            "created new region variable {:?} in {:?} with origin {:?}",
+            vid, universe, origin
         );
         return vid;
     }
@@ -662,6 +673,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
             self.make_subregion(origin, sup, sub);
 
             if let (ty::ReVar(sub), ty::ReVar(sup)) = (*sub, *sup) {
+                debug!("make_eqregion: uniying {:?} with {:?}", sub, sup);
                 self.unification_table.union(sub, sup);
                 self.any_unifications = true;
             }
@@ -707,7 +719,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
         }
     }
 
-    /// See `Verify::VerifyGenericBound`
+    /// See [`Verify::VerifyGenericBound`].
     pub fn verify_generic_bound(
         &mut self,
         origin: SubregionOrigin<'tcx>,
@@ -814,7 +826,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
         new_r
     }
 
-    fn universe(&self, region: Region<'tcx>) -> ty::UniverseIndex {
+    pub fn universe(&self, region: Region<'tcx>) -> ty::UniverseIndex {
         match *region {
             ty::ReScope(..)
             | ty::ReStatic
@@ -837,7 +849,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
             }).collect()
     }
 
-    /// See [`RegionInference::region_constraints_added_in_snapshot`]
+    /// See [`RegionInference::region_constraints_added_in_snapshot`].
     pub fn region_constraints_added_in_snapshot(&self, mark: &RegionSnapshot) -> Option<bool> {
         self.undo_log[mark.length..]
             .iter()
@@ -925,7 +937,8 @@ impl<'a, 'gcx, 'tcx> VerifyBound<'tcx> {
 }
 
 impl<'tcx> RegionConstraintData<'tcx> {
-    /// True if this region constraint data contains no constraints.
+    /// Returns `true` if this region constraint data contains no constraints, and `false`
+    /// otherwise.
     pub fn is_empty(&self) -> bool {
         let RegionConstraintData {
             constraints,
diff --git a/src/librustc/infer/resolve.rs b/src/librustc/infer/resolve.rs
index f6131c01b372f..4a8f0c34ead11 100644
--- a/src/librustc/infer/resolve.rs
+++ b/src/librustc/infer/resolve.rs
@@ -1,6 +1,6 @@
 use super::{InferCtxt, FixupError, FixupResult};
-use ty::{self, Ty, TyCtxt, TypeFoldable};
-use ty::fold::{TypeFolder, TypeVisitor};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
+use crate::ty::fold::{TypeFolder, TypeVisitor};
 
 ///////////////////////////////////////////////////////////////////////////
 // OPPORTUNISTIC TYPE RESOLVER
diff --git a/src/librustc/infer/sub.rs b/src/librustc/infer/sub.rs
index df76d1d3afb34..0cff42742c30a 100644
--- a/src/librustc/infer/sub.rs
+++ b/src/librustc/infer/sub.rs
@@ -1,11 +1,11 @@
 use super::SubregionOrigin;
 use super::combine::{CombineFields, RelationDir};
 
-use traits::Obligation;
-use ty::{self, Ty, TyCtxt};
-use ty::TyVar;
-use ty::fold::TypeFoldable;
-use ty::relate::{Cause, Relate, RelateResult, TypeRelation};
+use crate::traits::Obligation;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::TyVar;
+use crate::ty::fold::TypeFoldable;
+use crate::ty::relate::{Cause, Relate, RelateResult, TypeRelation};
 use std::mem;
 
 /// Ensures `a` is made a subtype of `b`. Returns `a` on success.
diff --git a/src/librustc/infer/type_variable.rs b/src/librustc/infer/type_variable.rs
index 3ec27bdcf1bcd..4c76818346b43 100644
--- a/src/librustc/infer/type_variable.rs
+++ b/src/librustc/infer/type_variable.rs
@@ -1,6 +1,6 @@
 use syntax::symbol::InternedString;
 use syntax_pos::Span;
-use ty::{self, Ty};
+use crate::ty::{self, Ty};
 
 use std::cmp;
 use std::marker::PhantomData;
@@ -188,7 +188,13 @@ impl<'tcx> TypeVariableTable<'tcx> {
         });
         assert_eq!(eq_key.vid.index, index as u32);
 
-        debug!("new_var(index={:?}, diverging={:?}, origin={:?}", eq_key.vid, diverging, origin);
+        debug!(
+            "new_var(index={:?}, universe={:?}, diverging={:?}, origin={:?}",
+            eq_key.vid,
+            universe,
+            diverging,
+            origin,
+        );
 
         eq_key.vid
     }
@@ -218,7 +224,7 @@ impl<'tcx> TypeVariableTable<'tcx> {
         self.sub_relations.find(vid)
     }
 
-    /// True if `a` and `b` have same "sub-root" (i.e., exists some
+    /// Returns `true` if `a` and `b` have same "sub-root" (i.e., exists some
     /// type X such that `forall i in {a, b}. (i <: X || X <: i)`.
     pub fn sub_unified(&mut self, a: ty::TyVid, b: ty::TyVid) -> bool {
         self.sub_root_var(a) == self.sub_root_var(b)
@@ -245,9 +251,9 @@ impl<'tcx> TypeVariableTable<'tcx> {
         }
     }
 
-    /// Creates a snapshot of the type variable state.  This snapshot
+    /// Creates a snapshot of the type variable state. This snapshot
     /// must later be committed (`commit()`) or rolled back
-    /// (`rollback_to()`).  Nested snapshots are permitted, but must
+    /// (`rollback_to()`). Nested snapshots are permitted, but must
     /// be processed in a stack-like fashion.
     pub fn snapshot(&mut self) -> Snapshot<'tcx> {
         Snapshot {
@@ -306,7 +312,7 @@ impl<'tcx> TypeVariableTable<'tcx> {
             .collect()
     }
 
-    /// Find the set of type variables that existed *before* `s`
+    /// Finds the set of type variables that existed *before* `s`
     /// but which have only been unified since `s` started, and
     /// return the types with which they were unified. So if we had
     /// a type variable `V0`, then we started the snapshot, then we
diff --git a/src/librustc/infer/unify_key.rs b/src/librustc/infer/unify_key.rs
index 068ff0c90e7fc..09f800d9f9bfc 100644
--- a/src/librustc/infer/unify_key.rs
+++ b/src/librustc/infer/unify_key.rs
@@ -1,4 +1,4 @@
-use ty::{self, FloatVarValue, IntVarValue, Ty, TyCtxt};
+use crate::ty::{self, FloatVarValue, IntVarValue, Ty, TyCtxt};
 use rustc_data_structures::unify::{NoError, EqUnifyValue, UnifyKey, UnifyValue};
 
 pub trait ToType {
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index fba9b8527677c..3d79b6777fa8b 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -26,9 +26,10 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
@@ -41,13 +42,11 @@
 #![feature(nll)]
 #![feature(non_exhaustive)]
 #![feature(proc_macro_internals)]
-#![feature(quote)]
 #![feature(optin_builtin_traits)]
 #![feature(refcell_replace_swap)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_attrs)]
 #![feature(slice_patterns)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(specialization)]
 #![feature(unboxed_closures)]
 #![feature(thread_local)]
@@ -65,40 +64,24 @@
 
 #![warn(elided_lifetimes_in_paths)]
 
-extern crate arena;
 #[macro_use] extern crate bitflags;
-extern crate core;
-extern crate fmt_macros;
 extern crate getopts;
-extern crate graphviz;
 #[macro_use] extern crate lazy_static;
 #[macro_use] extern crate scoped_tls;
 #[cfg(windows)]
 extern crate libc;
-extern crate polonius_engine;
-extern crate rustc_target;
 #[macro_use] extern crate rustc_data_structures;
-extern crate serialize;
-extern crate parking_lot;
-extern crate rustc_errors as errors;
-extern crate rustc_rayon as rayon;
-extern crate rustc_rayon_core as rayon_core;
+
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
-extern crate syntax_pos;
-extern crate jobserver;
-extern crate proc_macro;
-extern crate chalk_engine;
-extern crate rustc_fs_util;
 
-extern crate serialize as rustc_serialize; // used by deriving
+// FIXME: This import is used by deriving `RustcDecodable` and `RustcEncodable`. Removing this
+// results in a bunch of "failed to resolve" errors. Hopefully, the compiler moves to serde or
+// something, and we can get rid of this.
+#[allow(rust_2018_idioms)]
+extern crate serialize as rustc_serialize;
 
-extern crate rustc_apfloat;
-extern crate byteorder;
-extern crate backtrace;
-
-#[macro_use]
-extern crate smallvec;
+#[macro_use] extern crate smallvec;
 
 // Note that librustc doesn't actually depend on these crates, see the note in
 // `Cargo.toml` for this crate about why these are here.
@@ -166,7 +149,7 @@ pub mod util {
 // `libstd` uses the same trick.
 #[doc(hidden)]
 mod rustc {
-    pub use lint;
+    pub use crate::lint;
 }
 
 // FIXME(#27438): right now the unit tests of librustc don't refer to any actual
diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index c8d137a42b2e8..655707ff9bd0d 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -4,9 +4,9 @@
 //! compiler code, rather than using their own custom pass. Those
 //! lints are all available in `rustc_lint::builtin`.
 
+use crate::lint::{LintPass, LateLintPass, LintArray};
+use crate::session::Session;
 use errors::{Applicability, DiagnosticBuilder};
-use lint::{LintPass, LateLintPass, LintArray};
-use session::Session;
 use syntax::ast;
 use syntax::source_map::Span;
 
@@ -125,6 +125,12 @@ declare_lint! {
     "detect private items in public interfaces not caught by the old implementation"
 }
 
+declare_lint! {
+    pub EXPORTED_PRIVATE_DEPENDENCIES,
+    Warn,
+    "public interface leaks type from a private dependency"
+}
+
 declare_lint! {
     pub PUB_USE_OF_PRIVATE_EXTERN_CRATE,
     Deny,
@@ -346,6 +352,12 @@ declare_lint! {
     "outlives requirements can be inferred"
 }
 
+declare_lint! {
+    pub DUPLICATE_MATCHER_BINDING_NAME,
+    Warn,
+    "duplicate macro matcher binding name"
+}
+
 /// Some lints that are buffered from `libsyntax`. See `syntax::early_buffered_lints`.
 pub mod parser {
     declare_lint! {
@@ -368,12 +380,22 @@ declare_lint! {
     report_in_external_macro: true
 }
 
+declare_lint! {
+    pub AMBIGUOUS_ASSOCIATED_ITEMS,
+    Warn,
+    "ambiguous associated items"
+}
+
 /// Does nothing as a lint pass, but registers some `Lint`s
 /// that are used by other parts of the compiler.
 #[derive(Copy, Clone)]
 pub struct HardwiredLints;
 
 impl LintPass for HardwiredLints {
+    fn name(&self) -> &'static str {
+        "HardwiredLints"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(
             ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
@@ -395,6 +417,7 @@ impl LintPass for HardwiredLints {
             TRIVIAL_CASTS,
             TRIVIAL_NUMERIC_CASTS,
             PRIVATE_IN_PUBLIC,
+            EXPORTED_PRIVATE_DEPENDENCIES,
             PUB_USE_OF_PRIVATE_EXTERN_CRATE,
             INVALID_TYPE_PARAM_DEFAULT,
             CONST_ERR,
@@ -433,6 +456,7 @@ impl LintPass for HardwiredLints {
             parser::QUESTION_MARK_MACRO_SEP,
             parser::ILL_FORMED_ATTRIBUTE_INPUT,
             DEPRECATED_IN_FUTURE,
+            AMBIGUOUS_ASSOCIATED_ITEMS,
         )
     }
 }
@@ -449,6 +473,7 @@ pub enum BuiltinLintDiagnostics {
     MacroExpandedMacroExportsAccessedByAbsolutePaths(Span),
     ElidedLifetimesInPaths(usize, Span, bool, Span, String),
     UnknownCrateTypes(Span, String, String),
+    UnusedImports(String, Vec<(Span, String)>),
 }
 
 impl BuiltinLintDiagnostics {
@@ -462,7 +487,7 @@ impl BuiltinLintDiagnostics {
                     Ok(s) => (format!("dyn {}", s), Applicability::MachineApplicable),
                     Err(_) => ("dyn <type>".to_string(), Applicability::HasPlaceholders)
                 };
-                db.span_suggestion_with_applicability(span, "use `dyn`", sugg, app);
+                db.span_suggestion(span, "use `dyn`", sugg, app);
             }
             BuiltinLintDiagnostics::AbsPathWithModule(span) => {
                 let (sugg, app) = match sess.source_map().span_to_snippet(span) {
@@ -479,7 +504,7 @@ impl BuiltinLintDiagnostics {
                     }
                     Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders)
                 };
-                db.span_suggestion_with_applicability(span, "use `crate`", sugg, app);
+                db.span_suggestion(span, "use `crate`", sugg, app);
             }
             BuiltinLintDiagnostics::DuplicatedMacroExports(ident, earlier_span, later_span) => {
                 db.span_label(later_span, format!("`{}` already exported", ident));
@@ -520,7 +545,7 @@ impl BuiltinLintDiagnostics {
                         (insertion_span, anon_lts)
                     }
                 };
-                db.span_suggestion_with_applicability(
+                db.span_suggestion(
                     replace_span,
                     &format!("indicate the anonymous lifetime{}", if n >= 2 { "s" } else { "" }),
                     suggestion,
@@ -528,12 +553,16 @@ impl BuiltinLintDiagnostics {
                 );
             }
             BuiltinLintDiagnostics::UnknownCrateTypes(span, note, sugg) => {
-                db.span_suggestion_with_applicability(
-                    span,
-                    &note,
-                    sugg,
-                    Applicability::MaybeIncorrect
-                );
+                db.span_suggestion(span, &note, sugg, Applicability::MaybeIncorrect);
+            }
+            BuiltinLintDiagnostics::UnusedImports(message, replaces) => {
+                if !replaces.is_empty() {
+                    db.tool_only_multipart_suggestion(
+                        &message,
+                        replaces,
+                        Applicability::MachineApplicable,
+                    );
+                }
             }
         }
     }
diff --git a/src/librustc/lint/context.rs b/src/librustc/lint/context.rs
index f5a7919ef09c8..9032fcf8b612a 100644
--- a/src/librustc/lint/context.rs
+++ b/src/librustc/lint/context.rs
@@ -3,7 +3,7 @@
 //! The lint checking is mostly consolidated into one pass which runs
 //! after all other analyses. Throughout compilation, lint warnings
 //! can be added via the `add_lint` method on the Session structure. This
-//! requires a span and an id of the node that the lint is being added to. The
+//! requires a span and an ID of the node that the lint is being added to. The
 //! lint isn't actually emitted at that time because it is unknown what the
 //! actual lint level at that location is.
 //!
@@ -11,32 +11,33 @@
 //! A context keeps track of the current state of all lint levels.
 //! Upon entering a node of the ast which can modify the lint settings, the
 //! previous lint state is pushed onto a stack and the ast is then recursed
-//! upon.  As the ast is traversed, this keeps track of the current lint level
+//! upon. As the ast is traversed, this keeps track of the current lint level
 //! for all lint attributes.
 
 use self::TargetLint::*;
 
 use std::slice;
 use rustc_data_structures::sync::ReadGuard;
-use lint::{EarlyLintPassObject, LateLintPassObject};
-use lint::{Level, Lint, LintId, LintPass, LintBuffer};
-use lint::builtin::BuiltinLintDiagnostics;
-use lint::levels::{LintLevelSets, LintLevelsBuilder};
-use middle::privacy::AccessLevels;
-use rustc_serialize::{Decoder, Decodable, Encoder, Encodable};
-use session::{config, early_error, Session};
-use ty::{self, TyCtxt, Ty};
-use ty::layout::{LayoutError, LayoutOf, TyLayout};
-use util::nodemap::FxHashMap;
+use crate::lint::{EarlyLintPass, EarlyLintPassObject, LateLintPassObject};
+use crate::lint::{LintArray, Level, Lint, LintId, LintPass, LintBuffer};
+use crate::lint::builtin::BuiltinLintDiagnostics;
+use crate::lint::levels::{LintLevelSets, LintLevelsBuilder};
+use crate::middle::privacy::AccessLevels;
+use crate::rustc_serialize::{Decoder, Decodable, Encoder, Encodable};
+use crate::session::{config, early_error, Session};
+use crate::ty::{self, TyCtxt, Ty};
+use crate::ty::layout::{LayoutError, LayoutOf, TyLayout};
+use crate::util::nodemap::FxHashMap;
+use crate::util::common::time;
 
 use std::default::Default as StdDefault;
 use syntax::ast;
 use syntax::edition;
 use syntax_pos::{MultiSpan, Span, symbol::{LocalInternedString, Symbol}};
 use errors::DiagnosticBuilder;
-use hir;
-use hir::def_id::LOCAL_CRATE;
-use hir::intravisit as hir_visit;
+use crate::hir;
+use crate::hir::def_id::LOCAL_CRATE;
+use crate::hir::intravisit as hir_visit;
 use syntax::util::lev_distance::find_best_match_for_name;
 use syntax::visit as ast_visit;
 
@@ -74,7 +75,6 @@ pub struct LintSession<'a, PassObject> {
     passes: Option<Vec<PassObject>>,
 }
 
-
 /// Lints that are buffered up early on in the `Session` before the
 /// `LintLevels` is calculated
 #[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
@@ -175,18 +175,25 @@ impl LintStore {
     pub fn register_early_pass(&mut self,
                                sess: Option<&Session>,
                                from_plugin: bool,
+                               register_only: bool,
                                pass: EarlyLintPassObject) {
         self.push_pass(sess, from_plugin, &pass);
-        self.early_passes.as_mut().unwrap().push(pass);
+        if !register_only {
+            self.early_passes.as_mut().unwrap().push(pass);
+        }
     }
 
     pub fn register_pre_expansion_pass(
         &mut self,
         sess: Option<&Session>,
+        from_plugin: bool,
+        register_only: bool,
         pass: EarlyLintPassObject,
     ) {
-        self.push_pass(sess, false, &pass);
-        self.pre_expansion_passes.as_mut().unwrap().push(pass);
+        self.push_pass(sess, from_plugin, &pass);
+        if !register_only {
+            self.pre_expansion_passes.as_mut().unwrap().push(pass);
+        }
     }
 
     pub fn register_late_pass(&mut self,
@@ -535,6 +542,11 @@ pub struct EarlyContext<'a> {
     buffered: LintBuffer,
 }
 
+pub struct EarlyContextAndPass<'a, T: EarlyLintPass> {
+    context: EarlyContext<'a>,
+    pass: T,
+}
+
 /// Convenience macro for calling a `LintPass` method on every pass in the context.
 macro_rules! run_lints { ($cx:expr, $f:ident, $($args:expr),*) => ({
     // Move the vector of passes out of `$cx` so that we can
@@ -560,8 +572,6 @@ pub trait LintContext<'tcx>: Sized {
     fn lints(&self) -> &LintStore;
     fn lint_sess(&self) -> &LintSession<'tcx, Self::PassObject>;
     fn lint_sess_mut(&mut self) -> &mut LintSession<'tcx, Self::PassObject>;
-    fn enter_attrs(&mut self, attrs: &'tcx [ast::Attribute]);
-    fn exit_attrs(&mut self, attrs: &'tcx [ast::Attribute]);
 
     fn lookup_and_emit<S: Into<MultiSpan>>(&self,
                                            lint: &'static Lint,
@@ -624,15 +634,6 @@ pub trait LintContext<'tcx>: Sized {
     fn lint(&self, lint: &'static Lint, msg: &str) {
         self.lookup_and_emit(lint, None as Option<Span>, msg);
     }
-
-    /// Merge the lints specified by any lint attributes into the
-    /// current lint context, call the provided function, then reset the
-    /// lints in effect to their previous state.
-    fn with_lint_attrs<F>(&mut self,
-                          id: ast::NodeId,
-                          attrs: &'tcx [ast::Attribute],
-                          f: F)
-        where F: FnOnce(&mut Self);
 }
 
 
@@ -640,7 +641,6 @@ impl<'a> EarlyContext<'a> {
     fn new(
         sess: &'a Session,
         krate: &'a ast::Crate,
-        passes: Option<Vec<EarlyLintPassObject>>,
         buffered: LintBuffer,
     ) -> EarlyContext<'a> {
         EarlyContext {
@@ -648,27 +648,62 @@ impl<'a> EarlyContext<'a> {
             krate,
             lint_sess: LintSession {
                 lints: sess.lint_store.borrow(),
-                passes,
+                passes: None,
             },
             builder: LintLevelSets::builder(sess),
             buffered,
         }
     }
+}
 
+macro_rules! run_early_pass { ($cx:expr, $f:ident, $($args:expr),*) => ({
+    $cx.pass.$f(&$cx.context, $($args),*);
+}) }
+
+impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> {
     fn check_id(&mut self, id: ast::NodeId) {
-        for early_lint in self.buffered.take(id) {
-            self.lookup_and_emit_with_diagnostics(early_lint.lint_id.lint,
-                                                  Some(early_lint.span.clone()),
-                                                  &early_lint.msg,
-                                                  early_lint.diagnostic);
+        for early_lint in self.context.buffered.take(id) {
+            self.context.lookup_and_emit_with_diagnostics(
+                early_lint.lint_id.lint,
+                Some(early_lint.span.clone()),
+                &early_lint.msg,
+                early_lint.diagnostic
+            );
         }
     }
+
+    /// Merge the lints specified by any lint attributes into the
+    /// current lint context, call the provided function, then reset the
+    /// lints in effect to their previous state.
+    fn with_lint_attrs<F>(&mut self,
+                          id: ast::NodeId,
+                          attrs: &'a [ast::Attribute],
+                          f: F)
+        where F: FnOnce(&mut Self)
+    {
+        let push = self.context.builder.push(attrs);
+        self.check_id(id);
+        self.enter_attrs(attrs);
+        f(self);
+        self.exit_attrs(attrs);
+        self.context.builder.pop(push);
+    }
+
+    fn enter_attrs(&mut self, attrs: &'a [ast::Attribute]) {
+        debug!("early context: enter_attrs({:?})", attrs);
+        run_early_pass!(self, enter_lint_attrs, attrs);
+    }
+
+    fn exit_attrs(&mut self, attrs: &'a [ast::Attribute]) {
+        debug!("early context: exit_attrs({:?})", attrs);
+        run_early_pass!(self, exit_lint_attrs, attrs);
+    }
 }
 
 impl<'a, 'tcx> LintContext<'tcx> for LateContext<'a, 'tcx> {
     type PassObject = LateLintPassObject;
 
-    /// Get the overall compiler `Session` object.
+    /// Gets the overall compiler `Session` object.
     fn sess(&self) -> &Session {
         &self.tcx.sess
     }
@@ -685,16 +720,6 @@ impl<'a, 'tcx> LintContext<'tcx> for LateContext<'a, 'tcx> {
         &mut self.lint_sess
     }
 
-    fn enter_attrs(&mut self, attrs: &'tcx [ast::Attribute]) {
-        debug!("late context: enter_attrs({:?})", attrs);
-        run_lints!(self, enter_lint_attrs, attrs);
-    }
-
-    fn exit_attrs(&mut self, attrs: &'tcx [ast::Attribute]) {
-        debug!("late context: exit_attrs({:?})", attrs);
-        run_lints!(self, exit_lint_attrs, attrs);
-    }
-
     fn lookup<S: Into<MultiSpan>>(&self,
                                   lint: &'static Lint,
                                   span: Option<S>,
@@ -706,26 +731,12 @@ impl<'a, 'tcx> LintContext<'tcx> for LateContext<'a, 'tcx> {
             None => self.tcx.struct_lint_node(lint, id, msg),
         }
     }
-
-    fn with_lint_attrs<F>(&mut self,
-                          id: ast::NodeId,
-                          attrs: &'tcx [ast::Attribute],
-                          f: F)
-        where F: FnOnce(&mut Self)
-    {
-        let prev = self.last_ast_node_with_lint_attrs;
-        self.last_ast_node_with_lint_attrs = id;
-        self.enter_attrs(attrs);
-        f(self);
-        self.exit_attrs(attrs);
-        self.last_ast_node_with_lint_attrs = prev;
-    }
 }
 
 impl<'a> LintContext<'a> for EarlyContext<'a> {
     type PassObject = EarlyLintPassObject;
 
-    /// Get the overall compiler `Session` object.
+    /// Gets the overall compiler `Session` object.
     fn sess(&self) -> &Session {
         &self.sess
     }
@@ -742,16 +753,6 @@ impl<'a> LintContext<'a> for EarlyContext<'a> {
         &mut self.lint_sess
     }
 
-    fn enter_attrs(&mut self, attrs: &'a [ast::Attribute]) {
-        debug!("early context: enter_attrs({:?})", attrs);
-        run_lints!(self, enter_lint_attrs, attrs);
-    }
-
-    fn exit_attrs(&mut self, attrs: &'a [ast::Attribute]) {
-        debug!("early context: exit_attrs({:?})", attrs);
-        run_lints!(self, exit_lint_attrs, attrs);
-    }
-
     fn lookup<S: Into<MultiSpan>>(&self,
                                   lint: &'static Lint,
                                   span: Option<S>,
@@ -759,23 +760,36 @@ impl<'a> LintContext<'a> for EarlyContext<'a> {
                                   -> DiagnosticBuilder<'_> {
         self.builder.struct_lint(lint, span.map(|s| s.into()), msg)
     }
+}
 
+impl<'a, 'tcx> LateContext<'a, 'tcx> {
+    /// Merge the lints specified by any lint attributes into the
+    /// current lint context, call the provided function, then reset the
+    /// lints in effect to their previous state.
     fn with_lint_attrs<F>(&mut self,
                           id: ast::NodeId,
-                          attrs: &'a [ast::Attribute],
+                          attrs: &'tcx [ast::Attribute],
                           f: F)
         where F: FnOnce(&mut Self)
     {
-        let push = self.builder.push(attrs);
-        self.check_id(id);
+        let prev = self.last_ast_node_with_lint_attrs;
+        self.last_ast_node_with_lint_attrs = id;
         self.enter_attrs(attrs);
         f(self);
         self.exit_attrs(attrs);
-        self.builder.pop(push);
+        self.last_ast_node_with_lint_attrs = prev;
+    }
+
+    fn enter_attrs(&mut self, attrs: &'tcx [ast::Attribute]) {
+        debug!("late context: enter_attrs({:?})", attrs);
+        run_lints!(self, enter_lint_attrs, attrs);
+    }
+
+    fn exit_attrs(&mut self, attrs: &'tcx [ast::Attribute]) {
+        debug!("late context: exit_attrs({:?})", attrs);
+        run_lints!(self, exit_lint_attrs, attrs);
     }
-}
 
-impl<'a, 'tcx> LateContext<'a, 'tcx> {
     fn with_param_env<F>(&mut self, id: ast::NodeId, f: F)
         where F: FnOnce(&mut Self),
     {
@@ -941,11 +955,6 @@ impl<'a, 'tcx> hir_visit::Visitor<'tcx> for LateContext<'a, 'tcx> {
         hir_visit::walk_arm(self, a);
     }
 
-    fn visit_decl(&mut self, d: &'tcx hir::Decl) {
-        run_lints!(self, check_decl, d);
-        hir_visit::walk_decl(self, d);
-    }
-
     fn visit_generic_param(&mut self, p: &'tcx hir::GenericParam) {
         run_lints!(self, check_generic_param, p);
         hir_visit::walk_generic_param(self, p);
@@ -1008,26 +1017,26 @@ impl<'a, 'tcx> hir_visit::Visitor<'tcx> for LateContext<'a, 'tcx> {
     }
 }
 
-impl<'a> ast_visit::Visitor<'a> for EarlyContext<'a> {
+impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T> {
     fn visit_item(&mut self, it: &'a ast::Item) {
         self.with_lint_attrs(it.id, &it.attrs, |cx| {
-            run_lints!(cx, check_item, it);
+            run_early_pass!(cx, check_item, it);
             ast_visit::walk_item(cx, it);
-            run_lints!(cx, check_item_post, it);
+            run_early_pass!(cx, check_item_post, it);
         })
     }
 
     fn visit_foreign_item(&mut self, it: &'a ast::ForeignItem) {
         self.with_lint_attrs(it.id, &it.attrs, |cx| {
-            run_lints!(cx, check_foreign_item, it);
+            run_early_pass!(cx, check_foreign_item, it);
             ast_visit::walk_foreign_item(cx, it);
-            run_lints!(cx, check_foreign_item_post, it);
+            run_early_pass!(cx, check_foreign_item_post, it);
         })
     }
 
     fn visit_pat(&mut self, p: &'a ast::Pat) {
         let mut visit_subpats = true;
-        run_lints!(self, check_pat, p, &mut visit_subpats);
+        run_early_pass!(self, check_pat, p, &mut visit_subpats);
         self.check_id(p.id);
         if visit_subpats {
             ast_visit::walk_pat(self, p);
@@ -1036,23 +1045,23 @@ impl<'a> ast_visit::Visitor<'a> for EarlyContext<'a> {
 
     fn visit_expr(&mut self, e: &'a ast::Expr) {
         self.with_lint_attrs(e.id, &e.attrs, |cx| {
-            run_lints!(cx, check_expr, e);
+            run_early_pass!(cx, check_expr, e);
             ast_visit::walk_expr(cx, e);
         })
     }
 
     fn visit_stmt(&mut self, s: &'a ast::Stmt) {
-        run_lints!(self, check_stmt, s);
+        run_early_pass!(self, check_stmt, s);
         self.check_id(s.id);
         ast_visit::walk_stmt(self, s);
     }
 
     fn visit_fn(&mut self, fk: ast_visit::FnKind<'a>, decl: &'a ast::FnDecl,
                 span: Span, id: ast::NodeId) {
-        run_lints!(self, check_fn, fk, decl, span, id);
+        run_early_pass!(self, check_fn, fk, decl, span, id);
         self.check_id(id);
         ast_visit::walk_fn(self, fk, decl, span);
-        run_lints!(self, check_fn_post, fk, decl, span, id);
+        run_early_pass!(self, check_fn_post, fk, decl, span, id);
     }
 
     fn visit_variant_data(&mut self,
@@ -1061,120 +1070,120 @@ impl<'a> ast_visit::Visitor<'a> for EarlyContext<'a> {
                         g: &'a ast::Generics,
                         item_id: ast::NodeId,
                         _: Span) {
-        run_lints!(self, check_struct_def, s, ident, g, item_id);
+        run_early_pass!(self, check_struct_def, s, ident, g, item_id);
         self.check_id(s.id());
         ast_visit::walk_struct_def(self, s);
-        run_lints!(self, check_struct_def_post, s, ident, g, item_id);
+        run_early_pass!(self, check_struct_def_post, s, ident, g, item_id);
     }
 
     fn visit_struct_field(&mut self, s: &'a ast::StructField) {
         self.with_lint_attrs(s.id, &s.attrs, |cx| {
-            run_lints!(cx, check_struct_field, s);
+            run_early_pass!(cx, check_struct_field, s);
             ast_visit::walk_struct_field(cx, s);
         })
     }
 
     fn visit_variant(&mut self, v: &'a ast::Variant, g: &'a ast::Generics, item_id: ast::NodeId) {
         self.with_lint_attrs(item_id, &v.node.attrs, |cx| {
-            run_lints!(cx, check_variant, v, g);
+            run_early_pass!(cx, check_variant, v, g);
             ast_visit::walk_variant(cx, v, g, item_id);
-            run_lints!(cx, check_variant_post, v, g);
+            run_early_pass!(cx, check_variant_post, v, g);
         })
     }
 
     fn visit_ty(&mut self, t: &'a ast::Ty) {
-        run_lints!(self, check_ty, t);
+        run_early_pass!(self, check_ty, t);
         self.check_id(t.id);
         ast_visit::walk_ty(self, t);
     }
 
     fn visit_ident(&mut self, ident: ast::Ident) {
-        run_lints!(self, check_ident, ident);
+        run_early_pass!(self, check_ident, ident);
     }
 
     fn visit_mod(&mut self, m: &'a ast::Mod, s: Span, _a: &[ast::Attribute], n: ast::NodeId) {
-        run_lints!(self, check_mod, m, s, n);
+        run_early_pass!(self, check_mod, m, s, n);
         self.check_id(n);
         ast_visit::walk_mod(self, m);
-        run_lints!(self, check_mod_post, m, s, n);
+        run_early_pass!(self, check_mod_post, m, s, n);
     }
 
     fn visit_local(&mut self, l: &'a ast::Local) {
         self.with_lint_attrs(l.id, &l.attrs, |cx| {
-            run_lints!(cx, check_local, l);
+            run_early_pass!(cx, check_local, l);
             ast_visit::walk_local(cx, l);
         })
     }
 
     fn visit_block(&mut self, b: &'a ast::Block) {
-        run_lints!(self, check_block, b);
+        run_early_pass!(self, check_block, b);
         self.check_id(b.id);
         ast_visit::walk_block(self, b);
-        run_lints!(self, check_block_post, b);
+        run_early_pass!(self, check_block_post, b);
     }
 
     fn visit_arm(&mut self, a: &'a ast::Arm) {
-        run_lints!(self, check_arm, a);
+        run_early_pass!(self, check_arm, a);
         ast_visit::walk_arm(self, a);
     }
 
     fn visit_expr_post(&mut self, e: &'a ast::Expr) {
-        run_lints!(self, check_expr_post, e);
+        run_early_pass!(self, check_expr_post, e);
     }
 
     fn visit_generic_param(&mut self, param: &'a ast::GenericParam) {
-        run_lints!(self, check_generic_param, param);
+        run_early_pass!(self, check_generic_param, param);
         ast_visit::walk_generic_param(self, param);
     }
 
     fn visit_generics(&mut self, g: &'a ast::Generics) {
-        run_lints!(self, check_generics, g);
+        run_early_pass!(self, check_generics, g);
         ast_visit::walk_generics(self, g);
     }
 
     fn visit_where_predicate(&mut self, p: &'a ast::WherePredicate) {
-        run_lints!(self, check_where_predicate, p);
+        run_early_pass!(self, check_where_predicate, p);
         ast_visit::walk_where_predicate(self, p);
     }
 
     fn visit_poly_trait_ref(&mut self, t: &'a ast::PolyTraitRef, m: &'a ast::TraitBoundModifier) {
-        run_lints!(self, check_poly_trait_ref, t, m);
+        run_early_pass!(self, check_poly_trait_ref, t, m);
         ast_visit::walk_poly_trait_ref(self, t, m);
     }
 
     fn visit_trait_item(&mut self, trait_item: &'a ast::TraitItem) {
         self.with_lint_attrs(trait_item.id, &trait_item.attrs, |cx| {
-            run_lints!(cx, check_trait_item, trait_item);
+            run_early_pass!(cx, check_trait_item, trait_item);
             ast_visit::walk_trait_item(cx, trait_item);
-            run_lints!(cx, check_trait_item_post, trait_item);
+            run_early_pass!(cx, check_trait_item_post, trait_item);
         });
     }
 
     fn visit_impl_item(&mut self, impl_item: &'a ast::ImplItem) {
         self.with_lint_attrs(impl_item.id, &impl_item.attrs, |cx| {
-            run_lints!(cx, check_impl_item, impl_item);
+            run_early_pass!(cx, check_impl_item, impl_item);
             ast_visit::walk_impl_item(cx, impl_item);
-            run_lints!(cx, check_impl_item_post, impl_item);
+            run_early_pass!(cx, check_impl_item_post, impl_item);
         });
     }
 
     fn visit_lifetime(&mut self, lt: &'a ast::Lifetime) {
-        run_lints!(self, check_lifetime, lt);
+        run_early_pass!(self, check_lifetime, lt);
         self.check_id(lt.id);
     }
 
     fn visit_path(&mut self, p: &'a ast::Path, id: ast::NodeId) {
-        run_lints!(self, check_path, p, id);
+        run_early_pass!(self, check_path, p, id);
         self.check_id(id);
         ast_visit::walk_path(self, p);
     }
 
     fn visit_attribute(&mut self, attr: &'a ast::Attribute) {
-        run_lints!(self, check_attribute, attr);
+        run_early_pass!(self, check_attribute, attr);
     }
 
     fn visit_mac_def(&mut self, mac: &'a ast::MacroDef, id: ast::NodeId) {
-        run_lints!(self, check_mac_def, mac, id);
+        run_early_pass!(self, check_mac_def, mac, id);
         self.check_id(id);
     }
 
@@ -1186,12 +1195,12 @@ impl<'a> ast_visit::Visitor<'a> for EarlyContext<'a> {
         // want to get #53686 fixed quickly. -nmatsakis
         ast_visit::walk_path(self, &mac.node.path);
 
-        run_lints!(self, check_mac, mac);
+        run_early_pass!(self, check_mac, mac);
     }
 }
 
 
-/// Perform lint checking on a crate.
+/// Performs lint checking on a crate.
 ///
 /// Consumes the `lint_store` field of the `Session`.
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
@@ -1231,43 +1240,112 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     tcx.sess.lint_store.borrow_mut().late_passes = passes;
 }
 
-pub fn check_ast_crate(
+struct EarlyLintPassObjects<'a> {
+    lints: &'a mut [EarlyLintPassObject],
+}
+
+impl LintPass for EarlyLintPassObjects<'_> {
+    fn name(&self) -> &'static str {
+        panic!()
+    }
+
+    fn get_lints(&self) -> LintArray {
+        panic!()
+    }
+}
+
+macro_rules! expand_early_lint_pass_impl_methods {
+    ([$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => (
+        $(fn $name(&mut self, context: &EarlyContext<'_>, $($param: $arg),*) {
+            for obj in self.lints.iter_mut() {
+                obj.$name(context, $($param),*);
+            }
+        })*
+    )
+}
+
+macro_rules! early_lint_pass_impl {
+    ([], [$($methods:tt)*]) => (
+        impl EarlyLintPass for EarlyLintPassObjects<'_> {
+            expand_early_lint_pass_impl_methods!([$($methods)*]);
+        }
+    )
+}
+
+early_lint_methods!(early_lint_pass_impl, []);
+
+
+fn early_lint_crate<T: EarlyLintPass>(
+    sess: &Session,
+    krate: &ast::Crate,
+    pass: T,
+    buffered: LintBuffer,
+) -> LintBuffer {
+    let mut cx = EarlyContextAndPass {
+        context: EarlyContext::new(sess, krate, buffered),
+        pass,
+    };
+
+    // Visit the whole crate.
+    cx.with_lint_attrs(ast::CRATE_NODE_ID, &krate.attrs, |cx| {
+        // since the root module isn't visited as an item (because it isn't an
+        // item), warn for it here.
+        run_early_pass!(cx, check_crate, krate);
+
+        ast_visit::walk_crate(cx, krate);
+
+        run_early_pass!(cx, check_crate_post, krate);
+    });
+    cx.context.buffered
+}
+
+pub fn check_ast_crate<T: EarlyLintPass>(
     sess: &Session,
     krate: &ast::Crate,
     pre_expansion: bool,
+    builtin_lints: T,
 ) {
-    let (passes, buffered) = if pre_expansion {
+    let (mut passes, mut buffered) = if pre_expansion {
         (
-            sess.lint_store.borrow_mut().pre_expansion_passes.take(),
+            sess.lint_store.borrow_mut().pre_expansion_passes.take().unwrap(),
             LintBuffer::default(),
         )
     } else {
         (
-            sess.lint_store.borrow_mut().early_passes.take(),
+            sess.lint_store.borrow_mut().early_passes.take().unwrap(),
             sess.buffered_lints.borrow_mut().take().unwrap(),
         )
     };
-    let (passes, buffered) = {
-        let mut cx = EarlyContext::new(sess, krate, passes, buffered);
 
-        // Visit the whole crate.
-        cx.with_lint_attrs(ast::CRATE_NODE_ID, &krate.attrs, |cx| {
-            // since the root module isn't visited as an item (because it isn't an
-            // item), warn for it here.
-            run_lints!(cx, check_crate, krate);
+    if !sess.opts.debugging_opts.no_interleave_lints {
+        buffered = early_lint_crate(sess, krate, builtin_lints, buffered);
 
-            ast_visit::walk_crate(cx, krate);
-
-            run_lints!(cx, check_crate_post, krate);
-        });
-        (cx.lint_sess.passes, cx.buffered)
-    };
+        if !passes.is_empty() {
+            buffered = early_lint_crate(
+                sess,
+                krate,
+                EarlyLintPassObjects { lints: &mut passes[..] },
+                buffered,
+            );
+        }
+    } else {
+        for pass in &mut passes {
+            buffered = time(sess, &format!("running lint: {}", pass.name()), || {
+                early_lint_crate(
+                    sess,
+                    krate,
+                    EarlyLintPassObjects { lints: slice::from_mut(pass) },
+                    buffered,
+                )
+            });
+        }
+    }
 
     // Put the lint store levels and passes back in the session.
     if pre_expansion {
-        sess.lint_store.borrow_mut().pre_expansion_passes = passes;
+        sess.lint_store.borrow_mut().pre_expansion_passes = Some(passes);
     } else {
-        sess.lint_store.borrow_mut().early_passes = passes;
+        sess.lint_store.borrow_mut().early_passes = Some(passes);
     }
 
     // All of the buffered lints should have been emitted at this point.
diff --git a/src/librustc/lint/levels.rs b/src/librustc/lint/levels.rs
index 8b45a5a1504b5..924aa3fde0a08 100644
--- a/src/librustc/lint/levels.rs
+++ b/src/librustc/lint/levels.rs
@@ -1,20 +1,20 @@
 use std::cmp;
 
+use crate::hir::HirId;
+use crate::ich::StableHashingContext;
+use crate::lint::builtin;
+use crate::lint::context::CheckLintNameResult;
+use crate::lint::{self, Lint, LintId, Level, LintSource};
+use crate::session::Session;
+use crate::util::nodemap::FxHashMap;
 use errors::{Applicability, DiagnosticBuilder};
-use hir::HirId;
-use ich::StableHashingContext;
-use lint::builtin;
-use lint::context::CheckLintNameResult;
-use lint::{self, Lint, LintId, Level, LintSource};
 use rustc_data_structures::stable_hasher::{HashStable, ToStableHashKey,
                                            StableHasher, StableHasherResult};
-use session::Session;
 use syntax::ast;
 use syntax::attr;
 use syntax::feature_gate;
 use syntax::source_map::MultiSpan;
 use syntax::symbol::Symbol;
-use util::nodemap::FxHashMap;
 
 pub struct LintLevelSets {
     list: Vec<LintSet>,
@@ -324,7 +324,7 @@ impl<'a> LintLevelsBuilder<'a> {
                                     Some(li.span.into()),
                                     &msg,
                                 );
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     li.span,
                                     "change it to",
                                     new_lint_name.to_string(),
@@ -362,7 +362,7 @@ impl<'a> LintLevelsBuilder<'a> {
                                                               Some(li.span.into()),
                                                               &msg);
                         if let Some(new_name) = renamed {
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 li.span,
                                 "use the new name",
                                 new_name,
@@ -386,7 +386,7 @@ impl<'a> LintLevelsBuilder<'a> {
                                                 &msg);
 
                         if let Some(suggestion) = suggestion {
-                            db.span_suggestion_with_applicability(
+                            db.span_suggestion(
                                 li.span,
                                 "did you mean",
                                 suggestion.to_string(),
diff --git a/src/librustc/lint/mod.rs b/src/librustc/lint/mod.rs
index 730ce919bd295..859ceb4bd074d 100644
--- a/src/librustc/lint/mod.rs
+++ b/src/librustc/lint/mod.rs
@@ -23,26 +23,25 @@ pub use self::LintSource::*;
 
 use rustc_data_structures::sync::{self, Lrc};
 
+use crate::hir::def_id::{CrateNum, LOCAL_CRATE};
+use crate::hir::intravisit;
+use crate::hir;
+use crate::lint::builtin::{BuiltinLintDiagnostics, DUPLICATE_MATCHER_BINDING_NAME};
+use crate::lint::builtin::parser::{QUESTION_MARK_MACRO_SEP, ILL_FORMED_ATTRIBUTE_INPUT};
+use crate::session::{Session, DiagnosticMessageId};
+use crate::ty::TyCtxt;
+use crate::ty::query::Providers;
+use crate::util::nodemap::NodeMap;
 use errors::{DiagnosticBuilder, DiagnosticId};
-use hir::def_id::{CrateNum, LOCAL_CRATE};
-use hir::intravisit;
-use hir;
-use lint::builtin::BuiltinLintDiagnostics;
-use lint::builtin::parser::{QUESTION_MARK_MACRO_SEP, ILL_FORMED_ATTRIBUTE_INPUT};
-use session::{Session, DiagnosticMessageId};
 use std::{hash, ptr};
 use syntax::ast;
 use syntax::source_map::{MultiSpan, ExpnFormat};
 use syntax::early_buffered_lints::BufferedEarlyLintId;
 use syntax::edition::Edition;
 use syntax::symbol::Symbol;
-use syntax::visit as ast_visit;
 use syntax_pos::Span;
-use ty::TyCtxt;
-use ty::query::Providers;
-use util::nodemap::NodeMap;
 
-pub use lint::context::{LateContext, EarlyContext, LintContext, LintStore,
+pub use crate::lint::context::{LateContext, EarlyContext, LintContext, LintStore,
                         check_crate, check_ast_crate, CheckLintNameResult,
                         FutureIncompatibleInfo, BufferedEarlyLint};
 
@@ -73,7 +72,7 @@ pub struct Lint {
     /// `default_level`.
     pub edition_lint_opts: Option<(Edition, Level)>,
 
-    /// Whether this lint is reported even inside expansions of external macros
+    /// `true` if this lint is reported even inside expansions of external macros.
     pub report_in_external_macro: bool,
 }
 
@@ -83,10 +82,11 @@ impl Lint {
         match lint_id {
             BufferedEarlyLintId::QuestionMarkMacroSep => QUESTION_MARK_MACRO_SEP,
             BufferedEarlyLintId::IllFormedAttributeInput => ILL_FORMED_ATTRIBUTE_INPUT,
+            BufferedEarlyLintId::DuplicateMacroMatcherBindingName => DUPLICATE_MATCHER_BINDING_NAME,
         }
     }
 
-    /// Get the lint's name, with ASCII letters converted to lowercase.
+    /// Gets the lint's name, with ASCII letters converted to lowercase.
     pub fn name_lower(&self) -> String {
         self.name.to_ascii_lowercase()
     }
@@ -99,7 +99,7 @@ impl Lint {
     }
 }
 
-/// Declare a static item of type `&'static Lint`.
+/// Declares a static item of type `&'static Lint`.
 #[macro_export]
 macro_rules! declare_lint {
     ($vis: vis $NAME: ident, $Level: ident, $desc: expr) => (
@@ -150,7 +150,7 @@ macro_rules! declare_tool_lint {
     );
 }
 
-/// Declare a static `LintArray` and return it as an expression.
+/// Declares a static `LintArray` and return it as an expression.
 #[macro_export]
 macro_rules! lint_array {
     ($( $lint:expr ),* ,) => { lint_array!( $($lint),* ) };
@@ -162,7 +162,9 @@ macro_rules! lint_array {
 pub type LintArray = Vec<&'static Lint>;
 
 pub trait LintPass {
-    /// Get descriptions of the lints this `LintPass` object can emit.
+    fn name(&self) -> &'static str;
+
+    /// Gets descriptions of the lints this `LintPass` object can emit.
     ///
     /// N.B., there is no enforcement that the object only emits lints it registered.
     /// And some `rustc` internal `LintPass`es register lints to be emitted by other
@@ -192,7 +194,6 @@ macro_rules! late_lint_methods {
             fn check_stmt(a: &$hir hir::Stmt);
             fn check_arm(a: &$hir hir::Arm);
             fn check_pat(a: &$hir hir::Pat);
-            fn check_decl(a: &$hir hir::Decl);
             fn check_expr(a: &$hir hir::Expr);
             fn check_expr_post(a: &$hir hir::Expr);
             fn check_ty(a: &$hir hir::Ty);
@@ -308,6 +309,10 @@ macro_rules! declare_combined_late_lint_pass {
         }
 
         impl LintPass for $name {
+            fn name(&self) -> &'static str {
+                panic!()
+            }
+
             fn get_lints(&self) -> LintArray {
                 let mut lints = Vec::new();
                 $(lints.extend_from_slice(&self.$passes.get_lints());)*
@@ -317,57 +322,139 @@ macro_rules! declare_combined_late_lint_pass {
     )
 }
 
-pub trait EarlyLintPass: LintPass {
-    fn check_ident(&mut self, _: &EarlyContext<'_>, _: ast::Ident) { }
-    fn check_crate(&mut self, _: &EarlyContext<'_>, _: &ast::Crate) { }
-    fn check_crate_post(&mut self, _: &EarlyContext<'_>, _: &ast::Crate) { }
-    fn check_mod(&mut self, _: &EarlyContext<'_>, _: &ast::Mod, _: Span, _: ast::NodeId) { }
-    fn check_mod_post(&mut self, _: &EarlyContext<'_>, _: &ast::Mod, _: Span, _: ast::NodeId) { }
-    fn check_foreign_item(&mut self, _: &EarlyContext<'_>, _: &ast::ForeignItem) { }
-    fn check_foreign_item_post(&mut self, _: &EarlyContext<'_>, _: &ast::ForeignItem) { }
-    fn check_item(&mut self, _: &EarlyContext<'_>, _: &ast::Item) { }
-    fn check_item_post(&mut self, _: &EarlyContext<'_>, _: &ast::Item) { }
-    fn check_local(&mut self, _: &EarlyContext<'_>, _: &ast::Local) { }
-    fn check_block(&mut self, _: &EarlyContext<'_>, _: &ast::Block) { }
-    fn check_block_post(&mut self, _: &EarlyContext<'_>, _: &ast::Block) { }
-    fn check_stmt(&mut self, _: &EarlyContext<'_>, _: &ast::Stmt) { }
-    fn check_arm(&mut self, _: &EarlyContext<'_>, _: &ast::Arm) { }
-    fn check_pat(&mut self, _: &EarlyContext<'_>, _: &ast::Pat, _: &mut bool) { }
-    fn check_expr(&mut self, _: &EarlyContext<'_>, _: &ast::Expr) { }
-    fn check_expr_post(&mut self, _: &EarlyContext<'_>, _: &ast::Expr) { }
-    fn check_ty(&mut self, _: &EarlyContext<'_>, _: &ast::Ty) { }
-    fn check_generic_param(&mut self, _: &EarlyContext<'_>, _: &ast::GenericParam) { }
-    fn check_generics(&mut self, _: &EarlyContext<'_>, _: &ast::Generics) { }
-    fn check_where_predicate(&mut self, _: &EarlyContext<'_>, _: &ast::WherePredicate) { }
-    fn check_poly_trait_ref(&mut self, _: &EarlyContext<'_>, _: &ast::PolyTraitRef,
-                            _: &ast::TraitBoundModifier) { }
-    fn check_fn(&mut self, _: &EarlyContext<'_>,
-        _: ast_visit::FnKind<'_>, _: &ast::FnDecl, _: Span, _: ast::NodeId) { }
-    fn check_fn_post(&mut self, _: &EarlyContext<'_>,
-        _: ast_visit::FnKind<'_>, _: &ast::FnDecl, _: Span, _: ast::NodeId) { }
-    fn check_trait_item(&mut self, _: &EarlyContext<'_>, _: &ast::TraitItem) { }
-    fn check_trait_item_post(&mut self, _: &EarlyContext<'_>, _: &ast::TraitItem) { }
-    fn check_impl_item(&mut self, _: &EarlyContext<'_>, _: &ast::ImplItem) { }
-    fn check_impl_item_post(&mut self, _: &EarlyContext<'_>, _: &ast::ImplItem) { }
-    fn check_struct_def(&mut self, _: &EarlyContext<'_>,
-        _: &ast::VariantData, _: ast::Ident, _: &ast::Generics, _: ast::NodeId) { }
-    fn check_struct_def_post(&mut self, _: &EarlyContext<'_>,
-        _: &ast::VariantData, _: ast::Ident, _: &ast::Generics, _: ast::NodeId) { }
-    fn check_struct_field(&mut self, _: &EarlyContext<'_>, _: &ast::StructField) { }
-    fn check_variant(&mut self, _: &EarlyContext<'_>, _: &ast::Variant, _: &ast::Generics) { }
-    fn check_variant_post(&mut self, _: &EarlyContext<'_>, _: &ast::Variant, _: &ast::Generics) { }
-    fn check_lifetime(&mut self, _: &EarlyContext<'_>, _: &ast::Lifetime) { }
-    fn check_path(&mut self, _: &EarlyContext<'_>, _: &ast::Path, _: ast::NodeId) { }
-    fn check_attribute(&mut self, _: &EarlyContext<'_>, _: &ast::Attribute) { }
-    fn check_mac_def(&mut self, _: &EarlyContext<'_>, _: &ast::MacroDef, _id: ast::NodeId) { }
-    fn check_mac(&mut self, _: &EarlyContext<'_>, _: &ast::Mac) { }
-
-    /// Called when entering a syntax node that can have lint attributes such
-    /// as `#[allow(...)]`. Called with *all* the attributes of that node.
-    fn enter_lint_attrs(&mut self, _: &EarlyContext<'_>, _: &[ast::Attribute]) { }
-
-    /// Counterpart to `enter_lint_attrs`.
-    fn exit_lint_attrs(&mut self, _: &EarlyContext<'_>, _: &[ast::Attribute]) { }
+#[macro_export]
+macro_rules! early_lint_methods {
+    ($macro:path, $args:tt) => (
+        $macro!($args, [
+            fn check_ident(a: ast::Ident);
+            fn check_crate(a: &ast::Crate);
+            fn check_crate_post(a: &ast::Crate);
+            fn check_mod(a: &ast::Mod, b: Span, c: ast::NodeId);
+            fn check_mod_post(a: &ast::Mod, b: Span, c: ast::NodeId);
+            fn check_foreign_item(a: &ast::ForeignItem);
+            fn check_foreign_item_post(a: &ast::ForeignItem);
+            fn check_item(a: &ast::Item);
+            fn check_item_post(a: &ast::Item);
+            fn check_local(a: &ast::Local);
+            fn check_block(a: &ast::Block);
+            fn check_block_post(a: &ast::Block);
+            fn check_stmt(a: &ast::Stmt);
+            fn check_arm(a: &ast::Arm);
+            fn check_pat(a: &ast::Pat, b: &mut bool); // FIXME: &mut bool looks just broken
+            fn check_expr(a: &ast::Expr);
+            fn check_expr_post(a: &ast::Expr);
+            fn check_ty(a: &ast::Ty);
+            fn check_generic_param(a: &ast::GenericParam);
+            fn check_generics(a: &ast::Generics);
+            fn check_where_predicate(a: &ast::WherePredicate);
+            fn check_poly_trait_ref(a: &ast::PolyTraitRef,
+                                    b: &ast::TraitBoundModifier);
+            fn check_fn(a: syntax::visit::FnKind<'_>, b: &ast::FnDecl, c: Span, d_: ast::NodeId);
+            fn check_fn_post(
+                a: syntax::visit::FnKind<'_>,
+                b: &ast::FnDecl,
+                c: Span,
+                d: ast::NodeId
+            );
+            fn check_trait_item(a: &ast::TraitItem);
+            fn check_trait_item_post(a: &ast::TraitItem);
+            fn check_impl_item(a: &ast::ImplItem);
+            fn check_impl_item_post(a: &ast::ImplItem);
+            fn check_struct_def(
+                a: &ast::VariantData,
+                b: ast::Ident,
+                c: &ast::Generics,
+                d: ast::NodeId
+            );
+            fn check_struct_def_post(
+                a: &ast::VariantData,
+                b: ast::Ident,
+                c: &ast::Generics,
+                d: ast::NodeId
+            );
+            fn check_struct_field(a: &ast::StructField);
+            fn check_variant(a: &ast::Variant, b: &ast::Generics);
+            fn check_variant_post(a: &ast::Variant, b: &ast::Generics);
+            fn check_lifetime(a: &ast::Lifetime);
+            fn check_path(a: &ast::Path, b: ast::NodeId);
+            fn check_attribute(a: &ast::Attribute);
+            fn check_mac_def(a: &ast::MacroDef, b: ast::NodeId);
+            fn check_mac(a: &ast::Mac);
+
+            /// Called when entering a syntax node that can have lint attributes such
+            /// as `#[allow(...)]`. Called with *all* the attributes of that node.
+            fn enter_lint_attrs(a: &[ast::Attribute]);
+
+            /// Counterpart to `enter_lint_attrs`.
+            fn exit_lint_attrs(a: &[ast::Attribute]);
+        ]);
+    )
+}
+
+macro_rules! expand_early_lint_pass_methods {
+    ($context:ty, [$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => (
+        $(#[inline(always)] fn $name(&mut self, _: $context, $(_: $arg),*) {})*
+    )
+}
+
+macro_rules! declare_early_lint_pass {
+    ([], [$($methods:tt)*]) => (
+        pub trait EarlyLintPass: LintPass {
+            expand_early_lint_pass_methods!(&EarlyContext<'_>, [$($methods)*]);
+        }
+    )
+}
+
+early_lint_methods!(declare_early_lint_pass, []);
+
+#[macro_export]
+macro_rules! expand_combined_early_lint_pass_method {
+    ([$($passes:ident),*], $self: ident, $name: ident, $params:tt) => ({
+        $($self.$passes.$name $params;)*
+    })
+}
+
+#[macro_export]
+macro_rules! expand_combined_early_lint_pass_methods {
+    ($passes:tt, [$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => (
+        $(fn $name(&mut self, context: &EarlyContext<'_>, $($param: $arg),*) {
+            expand_combined_early_lint_pass_method!($passes, self, $name, (context, $($param),*));
+        })*
+    )
+}
+
+#[macro_export]
+macro_rules! declare_combined_early_lint_pass {
+    ([$v:vis $name:ident, [$($passes:ident: $constructor:expr,)*]], $methods:tt) => (
+        #[allow(non_snake_case)]
+        $v struct $name {
+            $($passes: $passes,)*
+        }
+
+        impl $name {
+            $v fn new() -> Self {
+                Self {
+                    $($passes: $constructor,)*
+                }
+            }
+        }
+
+        impl EarlyLintPass for $name {
+            expand_combined_early_lint_pass_methods!([$($passes),*], $methods);
+        }
+
+        impl LintPass for $name {
+            fn name(&self) -> &'static str {
+                panic!()
+            }
+
+            fn get_lints(&self) -> LintArray {
+                let mut lints = Vec::new();
+                $(lints.extend_from_slice(&self.$passes.get_lints());)*
+                lints
+            }
+        }
+    )
 }
 
 /// A lint pass boxed up as a trait object.
@@ -400,7 +487,7 @@ impl hash::Hash for LintId {
 }
 
 impl LintId {
-    /// Get the `LintId` for a `Lint`.
+    /// Gets the `LintId` for a `Lint`.
     pub fn of(lint: &'static Lint) -> LintId {
         LintId {
             lint,
@@ -411,7 +498,7 @@ impl LintId {
         self.lint.name
     }
 
-    /// Get the name of the lint.
+    /// Gets the name of the lint.
     pub fn to_string(&self) -> String {
         self.lint.name_lower()
     }
@@ -431,7 +518,7 @@ impl_stable_hash_for!(enum self::Level {
 });
 
 impl Level {
-    /// Convert a level to a lower-case string.
+    /// Converts a level to a lower-case string.
     pub fn as_str(self) -> &'static str {
         match self {
             Allow => "allow",
@@ -441,7 +528,7 @@ impl Level {
         }
     }
 
-    /// Convert a lower-case string to a level.
+    /// Converts a lower-case string to a level.
     pub fn from_str(x: &str) -> Option<Level> {
         match x {
             "allow" => Some(Allow),
@@ -592,7 +679,7 @@ pub fn struct_lint_level<'a>(sess: &'a Session,
             "this was previously accepted by the compiler but is being phased out; \
              it will become a hard error";
 
-        let explanation = if lint_id == LintId::of(::lint::builtin::UNSTABLE_NAME_COLLISIONS) {
+        let explanation = if lint_id == LintId::of(crate::lint::builtin::UNSTABLE_NAME_COLLISIONS) {
             "once this method is added to the standard library, \
              the ambiguity may cause an error or change in behavior!"
                 .to_owned()
diff --git a/src/librustc/macros.rs b/src/librustc/macros.rs
index 2978b35319944..ccae9d3ad5a82 100644
--- a/src/librustc/macros.rs
+++ b/src/librustc/macros.rs
@@ -62,38 +62,36 @@ macro_rules! __impl_stable_hash_field {
 #[macro_export]
 macro_rules! impl_stable_hash_for {
     // Enums
-    // FIXME(mark-i-m): Some of these should be `?` rather than `*`. See the git blame and change
-    // them back when `?` is supported again.
     (enum $enum_name:path {
         $( $variant:ident
            // this incorrectly allows specifying both tuple-like and struct-like fields, as in `Variant(a,b){c,d}`,
            // when it should be only one or the other
-           $( ( $($field:ident $(-> $delegate:tt)*),* ) )*
-           $( { $($named_field:ident $(-> $named_delegate:tt)*),* } )*
-        ),* $(,)*
+           $( ( $($field:ident $(-> $delegate:tt)?),* ) )?
+           $( { $($named_field:ident $(-> $named_delegate:tt)?),* } )?
+        ),* $(,)?
     }) => {
         impl_stable_hash_for!(
             impl<> for enum $enum_name [ $enum_name ] { $( $variant
-                $( ( $($field $(-> $delegate)*),* ) )*
-                $( { $($named_field $(-> $named_delegate)*),* } )*
+                $( ( $($field $(-> $delegate)?),* ) )?
+                $( { $($named_field $(-> $named_delegate)?),* } )?
             ),* }
         );
     };
     // We want to use the enum name both in the `impl ... for $enum_name` as well as for
     // importing all the variants. Unfortunately it seems we have to take the name
     // twice for this purpose
-    (impl<$($lt:lifetime $(: $lt_bound:lifetime)* ),* $(,)* $($T:ident),* $(,)*>
+    (impl<$($lt:lifetime $(: $lt_bound:lifetime)? ),* $(,)? $($T:ident),* $(,)?>
         for enum $enum_name:path
         [ $enum_path:path ]
     {
         $( $variant:ident
            // this incorrectly allows specifying both tuple-like and struct-like fields, as in `Variant(a,b){c,d}`,
            // when it should be only one or the other
-           $( ( $($field:ident $(-> $delegate:tt)*),* ) )*
-           $( { $($named_field:ident $(-> $named_delegate:tt)*),* } )*
-        ),* $(,)*
+           $( ( $($field:ident $(-> $delegate:tt)?),* ) )?
+           $( { $($named_field:ident $(-> $named_delegate:tt)?),* } )?
+        ),* $(,)?
     }) => {
-        impl<'a, $($lt $(: $lt_bound)*,)* $($T,)*>
+        impl<'a, $($lt $(: $lt_bound)?,)* $($T,)*>
             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>
             for $enum_name
             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
@@ -107,9 +105,9 @@ macro_rules! impl_stable_hash_for {
 
                 match *self {
                     $(
-                        $variant $( ( $(ref $field),* ) )* $( { $(ref $named_field),* } )* => {
-                            $($( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)*) );*)*
-                            $($( __impl_stable_hash_field!($named_field, __ctx, __hasher $(, $named_delegate)*) );*)*
+                        $variant $( ( $(ref $field),* ) )? $( { $(ref $named_field),* } )? => {
+                            $($( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*)?
+                            $($( __impl_stable_hash_field!($named_field, __ctx, __hasher $(, $named_delegate)?) );*)?
                         }
                     )*
                 }
@@ -117,16 +115,15 @@ macro_rules! impl_stable_hash_for {
         }
     };
     // Structs
-    // FIXME(mark-i-m): same here.
-    (struct $struct_name:path { $($field:ident $(-> $delegate:tt)*),*  $(,)* }) => {
+    (struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),* $(,)? }) => {
         impl_stable_hash_for!(
-            impl<'tcx> for struct $struct_name { $($field $(-> $delegate)*),* }
+            impl<'tcx> for struct $struct_name { $($field $(-> $delegate)?),* }
         );
     };
-    (impl<$($lt:lifetime $(: $lt_bound:lifetime)* ),* $(,)* $($T:ident),* $(,)*> for struct $struct_name:path {
-        $($field:ident $(-> $delegate:tt)*),* $(,)*
+    (impl<$($lt:lifetime $(: $lt_bound:lifetime)? ),* $(,)? $($T:ident),* $(,)?> for struct $struct_name:path {
+        $($field:ident $(-> $delegate:tt)?),* $(,)?
     }) => {
-        impl<'a, $($lt $(: $lt_bound)*,)* $($T,)*>
+        impl<'a, $($lt $(: $lt_bound)?,)* $($T,)*>
             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>> for $struct_name
             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
         {
@@ -138,21 +135,20 @@ macro_rules! impl_stable_hash_for {
                     $(ref $field),*
                 } = *self;
 
-                $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)*) );*
+                $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*
             }
         }
     };
     // Tuple structs
-    // We cannot use normale parentheses here, the parser won't allow it
-    // FIXME(mark-i-m): same here.
-    (tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)*),*  $(,)* }) => {
+    // We cannot use normal parentheses here, the parser won't allow it
+    (tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),*  $(,)? }) => {
         impl_stable_hash_for!(
-            impl<'tcx> for tuple_struct $struct_name { $($field $(-> $delegate)*),* }
+            impl<'tcx> for tuple_struct $struct_name { $($field $(-> $delegate)?),* }
         );
     };
-    (impl<$($lt:lifetime $(: $lt_bound:lifetime)* ),* $(,)* $($T:ident),* $(,)*>
-     for tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)*),*  $(,)* }) => {
-        impl<'a, $($lt $(: $lt_bound)*,)* $($T,)*>
+    (impl<$($lt:lifetime $(: $lt_bound:lifetime)? ),* $(,)? $($T:ident),* $(,)?>
+     for tuple_struct $struct_name:path { $($field:ident $(-> $delegate:tt)?),*  $(,)? }) => {
+        impl<'a, $($lt $(: $lt_bound)?,)* $($T,)*>
             ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>> for $struct_name
             where $($T: ::rustc_data_structures::stable_hasher::HashStable<$crate::ich::StableHashingContext<'a>>),*
         {
@@ -164,7 +160,7 @@ macro_rules! impl_stable_hash_for {
                     $(ref $field),*
                 ) = *self;
 
-                $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)*) );*
+                $( __impl_stable_hash_field!($field, __ctx, __hasher $(, $delegate)?) );*
             }
         }
     };
diff --git a/src/librustc/middle/borrowck.rs b/src/librustc/middle/borrowck.rs
index 120ba6b1d4e9f..2799f9424d919 100644
--- a/src/librustc/middle/borrowck.rs
+++ b/src/librustc/middle/borrowck.rs
@@ -1,6 +1,6 @@
-use ich::StableHashingContext;
-use hir::HirId;
-use util::nodemap::FxHashSet;
+use crate::ich::StableHashingContext;
+use crate::hir::HirId;
+use crate::util::nodemap::FxHashSet;
 
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
diff --git a/src/librustc/middle/cstore.rs b/src/librustc/middle/cstore.rs
index 9168bbf907f1e..6e9552a1e9209 100644
--- a/src/librustc/middle/cstore.rs
+++ b/src/librustc/middle/cstore.rs
@@ -2,13 +2,13 @@
 //! are *mostly* used as a part of that interface, but these should
 //! probably get a better home if someone can find one.
 
-use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
-use hir::map as hir_map;
-use hir::map::definitions::{DefKey, DefPathTable};
+use crate::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
+use crate::hir::map as hir_map;
+use crate::hir::map::definitions::{DefKey, DefPathTable};
 use rustc_data_structures::svh::Svh;
-use ty::{self, TyCtxt};
-use session::{Session, CrateDisambiguator};
-use session::search_paths::PathKind;
+use crate::ty::{self, TyCtxt};
+use crate::session::{Session, CrateDisambiguator};
+use crate::session::search_paths::PathKind;
 
 use std::any::Any;
 use std::path::{Path, PathBuf};
diff --git a/src/librustc/middle/dead.rs b/src/librustc/middle/dead.rs
index 0c769c91801b8..569968bd6d4bf 100644
--- a/src/librustc/middle/dead.rs
+++ b/src/librustc/middle/dead.rs
@@ -2,18 +2,18 @@
 // closely. The idea is that all reachable symbols are live, codes called
 // from live codes are live, and everything else is dead.
 
-use hir::Node;
-use hir::{self, PatKind};
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
-use hir::itemlikevisit::ItemLikeVisitor;
-
-use hir::def::Def;
-use hir::CodegenFnAttrFlags;
-use hir::def_id::{DefId, LOCAL_CRATE};
-use lint;
-use middle::privacy;
-use ty::{self, TyCtxt};
-use util::nodemap::FxHashSet;
+use crate::hir::Node;
+use crate::hir::{self, PatKind};
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::hir::itemlikevisit::ItemLikeVisitor;
+
+use crate::hir::def::Def;
+use crate::hir::CodegenFnAttrFlags;
+use crate::hir::def_id::{DefId, LOCAL_CRATE};
+use crate::lint;
+use crate::middle::privacy;
+use crate::ty::{self, TyCtxt};
+use crate::util::nodemap::FxHashSet;
 
 use rustc_data_structures::fx::FxHashMap;
 
@@ -112,7 +112,7 @@ impl<'a, 'tcx> MarkSymbolVisitor<'a, 'tcx> {
 
     fn handle_field_pattern_match(&mut self, lhs: &hir::Pat, def: Def,
                                   pats: &[source_map::Spanned<hir::FieldPat>]) {
-        let variant = match self.tables.node_id_to_type(lhs.hir_id).sty {
+        let variant = match self.tables.node_type(lhs.hir_id).sty {
             ty::Adt(adt, _) => adt.variant_of_def(def),
             _ => span_bug!(lhs.span, "non-ADT in struct pattern")
         };
@@ -409,7 +409,7 @@ fn create_and_seed_worklist<'a, 'tcx>(
         }
     }).chain(
         // Seed entry point
-        tcx.sess.entry_fn.borrow().map(|(id, _, _)| id)
+        tcx.entry_fn(LOCAL_CRATE).map(|(def_id, _)| tcx.hir().as_local_node_id(def_id).unwrap())
     ).collect::<Vec<_>>();
 
     // Seed implemented trait items
diff --git a/src/librustc/middle/dependency_format.rs b/src/librustc/middle/dependency_format.rs
index 16c9344a03722..a24d25cba1184 100644
--- a/src/librustc/middle/dependency_format.rs
+++ b/src/librustc/middle/dependency_format.rs
@@ -51,13 +51,13 @@
 //! Additionally, the algorithm is geared towards finding *any* solution rather
 //! than finding a number of solutions (there are normally quite a few).
 
-use hir::def_id::CrateNum;
+use crate::hir::def_id::CrateNum;
 
-use session::config;
-use ty::TyCtxt;
-use middle::cstore::{self, DepKind};
-use middle::cstore::LinkagePreference::{self, RequireStatic, RequireDynamic};
-use util::nodemap::FxHashMap;
+use crate::session::config;
+use crate::ty::TyCtxt;
+use crate::middle::cstore::{self, DepKind};
+use crate::middle::cstore::LinkagePreference::{self, RequireStatic, RequireDynamic};
+use crate::util::nodemap::FxHashMap;
 use rustc_target::spec::PanicStrategy;
 
 /// A list of dependencies for a certain crate type.
diff --git a/src/librustc/middle/entry.rs b/src/librustc/middle/entry.rs
index 6b593a1a9f9b2..2d0e6c3917bb8 100644
--- a/src/librustc/middle/entry.rs
+++ b/src/librustc/middle/entry.rs
@@ -1,13 +1,15 @@
-use hir::map as hir_map;
-use hir::def_id::{CRATE_DEF_INDEX};
-use session::{config, Session};
-use session::config::EntryFnType;
+use crate::hir::map as hir_map;
+use crate::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
+use crate::session::{config, Session};
+use crate::session::config::EntryFnType;
 use syntax::ast::NodeId;
 use syntax::attr;
 use syntax::entry::EntryPointType;
 use syntax_pos::Span;
-use hir::{Item, ItemKind, ImplItem, TraitItem};
-use hir::itemlikevisit::ItemLikeVisitor;
+use crate::hir::{Item, ItemKind, ImplItem, TraitItem};
+use crate::hir::itemlikevisit::ItemLikeVisitor;
+use crate::ty::TyCtxt;
+use crate::ty::query::Providers;
 
 struct EntryContext<'a, 'tcx: 'a> {
     session: &'a Session,
@@ -45,36 +47,34 @@ impl<'a, 'tcx> ItemLikeVisitor<'tcx> for EntryContext<'a, 'tcx> {
     }
 }
 
-pub fn find_entry_point(session: &Session,
-                        hir_map: &hir_map::Map<'_>,
-                        crate_name: &str) {
-    let any_exe = session.crate_types.borrow().iter().any(|ty| {
+fn entry_fn(tcx: TyCtxt<'_, '_, '_>, cnum: CrateNum) -> Option<(DefId, EntryFnType)> {
+    assert_eq!(cnum, LOCAL_CRATE);
+
+    let any_exe = tcx.sess.crate_types.borrow().iter().any(|ty| {
         *ty == config::CrateType::Executable
     });
     if !any_exe {
         // No need to find a main function
-        session.entry_fn.set(None);
-        return
+        return None;
     }
 
     // If the user wants no main function at all, then stop here.
-    if attr::contains_name(&hir_map.krate().attrs, "no_main") {
-        session.entry_fn.set(None);
-        return
+    if attr::contains_name(&tcx.hir().krate().attrs, "no_main") {
+        return None;
     }
 
     let mut ctxt = EntryContext {
-        session,
-        map: hir_map,
+        session: tcx.sess,
+        map: tcx.hir(),
         main_fn: None,
         attr_main_fn: None,
         start_fn: None,
         non_main_fns: Vec::new(),
     };
 
-    hir_map.krate().visit_all_item_likes(&mut ctxt);
+    tcx.hir().krate().visit_all_item_likes(&mut ctxt);
 
-    configure_main(&mut ctxt, crate_name);
+    configure_main(tcx, &ctxt)
 }
 
 // Beware, this is duplicated in `libsyntax/entry.rs`, so make sure to keep
@@ -135,43 +135,58 @@ fn find_item(item: &Item, ctxt: &mut EntryContext<'_, '_>, at_root: bool) {
                     .span_label(item.span, "multiple `start` functions")
                     .emit();
             }
-        },
-        EntryPointType::None => ()
+        }
+        EntryPointType::None => (),
     }
 }
 
-fn configure_main(this: &mut EntryContext<'_, '_>, crate_name: &str) {
-    if let Some((node_id, span)) = this.start_fn {
-        this.session.entry_fn.set(Some((node_id, span, EntryFnType::Start)));
-    } else if let Some((node_id, span)) = this.attr_main_fn {
-        this.session.entry_fn.set(Some((node_id, span, EntryFnType::Main)));
-    } else if let Some((node_id, span)) = this.main_fn {
-        this.session.entry_fn.set(Some((node_id, span, EntryFnType::Main)));
+fn configure_main(
+    tcx: TyCtxt<'_, '_, '_>,
+    visitor: &EntryContext<'_, '_>,
+) -> Option<(DefId, EntryFnType)> {
+    if let Some((node_id, _)) = visitor.start_fn {
+        Some((tcx.hir().local_def_id(node_id), EntryFnType::Start))
+    } else if let Some((node_id, _)) = visitor.attr_main_fn {
+        Some((tcx.hir().local_def_id(node_id), EntryFnType::Main))
+    } else if let Some((node_id, _)) = visitor.main_fn {
+        Some((tcx.hir().local_def_id(node_id), EntryFnType::Main))
     } else {
         // No main function
-        this.session.entry_fn.set(None);
-        let mut err = struct_err!(this.session, E0601,
-            "`main` function not found in crate `{}`", crate_name);
-        if !this.non_main_fns.is_empty() {
+        let mut err = struct_err!(tcx.sess, E0601,
+            "`main` function not found in crate `{}`", tcx.crate_name(LOCAL_CRATE));
+        if !visitor.non_main_fns.is_empty() {
             // There were some functions named 'main' though. Try to give the user a hint.
             err.note("the main function must be defined at the crate level \
                       but you have one or more functions named 'main' that are not \
                       defined at the crate level. Either move the definition or \
                       attach the `#[main]` attribute to override this behavior.");
-            for &(_, span) in &this.non_main_fns {
+            for &(_, span) in &visitor.non_main_fns {
                 err.span_note(span, "here is a function named 'main'");
             }
             err.emit();
-            this.session.abort_if_errors();
+            tcx.sess.abort_if_errors();
         } else {
-            if let Some(ref filename) = this.session.local_crate_source_file {
+            if let Some(ref filename) = tcx.sess.local_crate_source_file {
                 err.note(&format!("consider adding a `main` function to `{}`", filename.display()));
             }
-            if this.session.teach(&err.get_code().unwrap()) {
+            if tcx.sess.teach(&err.get_code().unwrap()) {
                 err.note("If you don't know the basics of Rust, you can go look to the Rust Book \
                           to get started: https://doc.rust-lang.org/book/");
             }
             err.emit();
         }
+
+        None
     }
 }
+
+pub fn find_entry_point(tcx: TyCtxt<'_, '_, '_>) -> Option<(DefId, EntryFnType)> {
+    tcx.entry_fn(LOCAL_CRATE)
+}
+
+pub fn provide(providers: &mut Providers<'_>) {
+    *providers = Providers {
+        entry_fn,
+        ..*providers
+    };
+}
diff --git a/src/librustc/middle/exported_symbols.rs b/src/librustc/middle/exported_symbols.rs
index a0a73ea0b81fb..6c43068a22772 100644
--- a/src/librustc/middle/exported_symbols.rs
+++ b/src/librustc/middle/exported_symbols.rs
@@ -1,11 +1,11 @@
-use hir::def_id::{DefId, LOCAL_CRATE};
-use ich::StableHashingContext;
+use crate::hir::def_id::{DefId, LOCAL_CRATE};
+use crate::ich::StableHashingContext;
 use rustc_data_structures::stable_hasher::{StableHasher, HashStable,
                                            StableHasherResult};
 use std::cmp;
 use std::mem;
-use ty;
-use ty::subst::Substs;
+use crate::ty;
+use crate::ty::subst::Substs;
 
 /// The SymbolExportLevel of a symbols specifies from which kinds of crates
 /// the symbol will be exported. `C` symbols will be exported from any
diff --git a/src/librustc/middle/expr_use_visitor.rs b/src/librustc/middle/expr_use_visitor.rs
index c1aa25b6b75c2..8da20ba426663 100644
--- a/src/librustc/middle/expr_use_visitor.rs
+++ b/src/librustc/middle/expr_use_visitor.rs
@@ -1,4 +1,4 @@
-//! A different sort of visitor for walking fn bodies.  Unlike the
+//! A different sort of visitor for walking fn bodies. Unlike the
 //! normal visitor, which just walks the entire body in one shot, the
 //! `ExprUseVisitor` determines how expressions are being used.
 
@@ -9,20 +9,20 @@ pub use self::MatchMode::*;
 use self::TrackMatchMode::*;
 use self::OverloadedCallType::*;
 
-use hir::def::Def;
-use hir::def_id::DefId;
-use infer::InferCtxt;
-use middle::mem_categorization as mc;
-use middle::region;
-use ty::{self, TyCtxt, adjustment};
+use crate::hir::def::Def;
+use crate::hir::def_id::DefId;
+use crate::infer::InferCtxt;
+use crate::middle::mem_categorization as mc;
+use crate::middle::region;
+use crate::ty::{self, TyCtxt, adjustment};
 
-use hir::{self, PatKind};
+use crate::hir::{self, PatKind};
 use rustc_data_structures::sync::Lrc;
 use std::rc::Rc;
 use syntax::ast;
 use syntax::ptr::P;
 use syntax_pos::Span;
-use util::nodemap::ItemLocalSet;
+use crate::util::nodemap::ItemLocalSet;
 
 ///////////////////////////////////////////////////////////////////////////
 // The Delegate trait
@@ -589,21 +589,17 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
 
     fn walk_stmt(&mut self, stmt: &hir::Stmt) {
         match stmt.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                match decl.node {
-                    hir::DeclKind::Local(ref local) => {
-                        self.walk_local(&local);
-                    }
+            hir::StmtKind::Local(ref local) => {
+                self.walk_local(&local);
+            }
 
-                    hir::DeclKind::Item(_) => {
-                        // we don't visit nested items in this visitor,
-                        // only the fn body we were given.
-                    }
-                }
+            hir::StmtKind::Item(_) => {
+                // we don't visit nested items in this visitor,
+                // only the fn body we were given.
             }
 
-            hir::StmtKind::Expr(ref expr, _) |
-            hir::StmtKind::Semi(ref expr, _) => {
+            hir::StmtKind::Expr(ref expr) |
+            hir::StmtKind::Semi(ref expr) => {
                 self.consume_expr(&expr);
             }
         }
@@ -804,8 +800,8 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
         self.consume_expr(&arm.body);
     }
 
-    /// Walks a pat that occurs in isolation (i.e., top-level of fn
-    /// arg or let binding.  *Not* a match arm or nested pat.)
+    /// Walks a pat that occurs in isolation (i.e., top-level of fn argument or
+    /// let binding, and *not* a match arm or nested pat.)
     fn walk_irrefutable_pat(&mut self, cmt_discr: mc::cmt<'tcx>, pat: &hir::Pat) {
         let mut mode = Unknown;
         self.determine_pat_move_mode(cmt_discr.clone(), pat, &mut mode);
diff --git a/src/librustc/middle/free_region.rs b/src/librustc/middle/free_region.rs
index 6e9eadca6a521..fc345df655150 100644
--- a/src/librustc/middle/free_region.rs
+++ b/src/librustc/middle/free_region.rs
@@ -1,14 +1,12 @@
-//! This file handles the relationships between free regions --
-//! meaning lifetime parameters. Ordinarily, free regions are
-//! unrelated to one another, but they can be related via implied or
-//! explicit bounds.  In that case, we track the bounds using the
-//! `TransitiveRelation` type and use that to decide when one free
-//! region outlives another and so forth.
+//! This module handles the relationships between "free regions", i.e., lifetime parameters.
+//! Ordinarily, free regions are unrelated to one another, but they can be related via implied
+//! or explicit bounds. In that case, we track the bounds using the `TransitiveRelation` type,
+//! and use that to decide when one free region outlives another, and so forth.
 
-use infer::outlives::free_region_map::{FreeRegionMap, FreeRegionRelations};
-use hir::def_id::DefId;
-use middle::region;
-use ty::{self, TyCtxt, Region};
+use crate::infer::outlives::free_region_map::{FreeRegionMap, FreeRegionRelations};
+use crate::hir::def_id::DefId;
+use crate::middle::region;
+use crate::ty::{self, TyCtxt, Region};
 
 /// Combines a `region::ScopeTree` (which governs relationships between
 /// scopes) and a `FreeRegionMap` (which governs relationships between
@@ -16,17 +14,17 @@ use ty::{self, TyCtxt, Region};
 /// regions.
 ///
 /// This stuff is a bit convoluted and should be refactored, but as we
-/// move to NLL it'll all go away anyhow.
+/// transition to NLL, it'll all go away anyhow.
 pub struct RegionRelations<'a, 'gcx: 'tcx, 'tcx: 'a> {
     pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
 
-    /// context used to fetch the region maps
+    /// The context used to fetch the region maps.
     pub context: DefId,
 
-    /// region maps for the given context
+    /// The region maps for the given context.
     pub region_scope_tree: &'a region::ScopeTree,
 
-    /// free-region relationships
+    /// Free-region relationships.
     pub free_regions: &'a FreeRegionMap<'tcx>,
 }
 
@@ -45,7 +43,7 @@ impl<'a, 'gcx, 'tcx> RegionRelations<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Determines whether one region is a subregion of another.  This is intended to run *after
+    /// Determines whether one region is a subregion of another. This is intended to run *after
     /// inference* and sadly the logic is somewhat duplicated with the code in infer.rs.
     pub fn is_subregion_of(&self,
                            sub_region: ty::Region<'tcx>,
@@ -86,7 +84,7 @@ impl<'a, 'gcx, 'tcx> RegionRelations<'a, 'gcx, 'tcx> {
         result
     }
 
-    /// Determines whether this free-region is required to be 'static
+    /// Determines whether this free region is required to be `'static`.
     fn is_static(&self, super_region: ty::Region<'tcx>) -> bool {
         debug!("is_static(super_region={:?})", super_region);
         match *super_region {
diff --git a/src/librustc/middle/intrinsicck.rs b/src/librustc/middle/intrinsicck.rs
index 1716daaa107c4..ce20ca39533b1 100644
--- a/src/librustc/middle/intrinsicck.rs
+++ b/src/librustc/middle/intrinsicck.rs
@@ -1,19 +1,33 @@
-use hir::def::Def;
-use hir::def_id::DefId;
-use ty::{self, Ty, TyCtxt};
-use ty::layout::{LayoutError, Pointer, SizeSkeleton, VariantIdx};
+use crate::hir::def::Def;
+use crate::hir::def_id::DefId;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::layout::{LayoutError, Pointer, SizeSkeleton, VariantIdx};
+use crate::ty::query::Providers;
 
 use rustc_target::spec::abi::Abi::RustIntrinsic;
 use rustc_data_structures::indexed_vec::Idx;
 use syntax_pos::Span;
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
-use hir;
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::hir;
 
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
-    let mut visitor = ItemVisitor {
-        tcx,
+    for &module in tcx.hir().krate().modules.keys() {
+        tcx.ensure().check_mod_intrinsics(tcx.hir().local_def_id(module));
+    }
+}
+
+fn check_mod_intrinsics<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
+    tcx.hir().visit_item_likes_in_module(
+        module_def_id,
+        &mut ItemVisitor { tcx }.as_deep_visitor()
+    );
+}
+
+pub fn provide(providers: &mut Providers<'_>) {
+    *providers = Providers {
+        check_mod_intrinsics,
+        ..*providers
     };
-    tcx.hir().krate().visit_all_item_likes(&mut visitor.as_deep_visitor());
 }
 
 struct ItemVisitor<'a, 'tcx: 'a> {
@@ -151,7 +165,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ExprVisitor<'a, 'tcx> {
         };
         if let Def::Fn(did) = def {
             if self.def_id_is_transmute(did) {
-                let typ = self.tables.node_id_to_type(expr.hir_id);
+                let typ = self.tables.node_type(expr.hir_id);
                 let sig = typ.fn_sig(self.tcx);
                 let from = sig.inputs().skip_binder()[0];
                 let to = *sig.output().skip_binder();
diff --git a/src/librustc/middle/lang_items.rs b/src/librustc/middle/lang_items.rs
index c203ea96f3d64..3f9230ab551d5 100644
--- a/src/librustc/middle/lang_items.rs
+++ b/src/librustc/middle/lang_items.rs
@@ -11,17 +11,17 @@
 
 pub use self::LangItem::*;
 
-use hir::def_id::DefId;
-use hir::check_attr::Target;
-use ty::{self, TyCtxt};
-use middle::weak_lang_items;
-use util::nodemap::FxHashMap;
+use crate::hir::def_id::DefId;
+use crate::hir::check_attr::Target;
+use crate::ty::{self, TyCtxt};
+use crate::middle::weak_lang_items;
+use crate::util::nodemap::FxHashMap;
 
 use syntax::ast;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
-use hir::itemlikevisit::ItemLikeVisitor;
-use hir;
+use crate::hir::itemlikevisit::ItemLikeVisitor;
+use crate::hir;
 
 // The actual lang items defined come at the end of this file in one handy table.
 // So you probably just want to nip down to the end.
@@ -299,6 +299,8 @@ language_item_table! {
 
     GeneratorStateLangItem,      "generator_state",    gen_state,               Target::Enum;
     GeneratorTraitLangItem,      "generator",          gen_trait,               Target::Trait;
+    UnpinTraitLangItem,          "unpin",              unpin_trait,             Target::Trait;
+    PinTypeLangItem,             "pin",                pin_type,                Target::Struct;
 
     EqTraitLangItem,             "eq",                 eq_trait,                Target::Trait;
     PartialOrdTraitLangItem,     "partial_ord",        partial_ord_trait,       Target::Trait;
diff --git a/src/librustc/middle/lib_features.rs b/src/librustc/middle/lib_features.rs
index 8c23377324f1f..331343e052dea 100644
--- a/src/librustc/middle/lib_features.rs
+++ b/src/librustc/middle/lib_features.rs
@@ -4,11 +4,11 @@
 // and `#[unstable (..)]`), but are not declared in one single location
 // (unlike lang features), which means we need to collect them instead.
 
-use ty::TyCtxt;
+use crate::ty::TyCtxt;
+use crate::hir::intravisit::{self, NestedVisitorMap, Visitor};
 use syntax::symbol::Symbol;
 use syntax::ast::{Attribute, MetaItem, MetaItemKind};
 use syntax_pos::Span;
-use hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_data_structures::fx::{FxHashSet, FxHashMap};
 use errors::DiagnosticId;
 
diff --git a/src/librustc/middle/liveness.rs b/src/librustc/middle/liveness.rs
index a78cf1a471b4b..d3925f40e09e7 100644
--- a/src/librustc/middle/liveness.rs
+++ b/src/librustc/middle/liveness.rs
@@ -1,27 +1,27 @@
-//! A classic liveness analysis based on dataflow over the AST.  Computes,
+//! A classic liveness analysis based on dataflow over the AST. Computes,
 //! for each local variable in a function, whether that variable is live
-//! at a given point.  Program execution points are identified by their
-//! id.
+//! at a given point. Program execution points are identified by their
+//! IDs.
 //!
 //! # Basic idea
 //!
-//! The basic model is that each local variable is assigned an index.  We
+//! The basic model is that each local variable is assigned an index. We
 //! represent sets of local variables using a vector indexed by this
-//! index.  The value in the vector is either 0, indicating the variable
-//! is dead, or the id of an expression that uses the variable.
+//! index. The value in the vector is either 0, indicating the variable
+//! is dead, or the ID of an expression that uses the variable.
 //!
-//! We conceptually walk over the AST in reverse execution order.  If we
-//! find a use of a variable, we add it to the set of live variables.  If
+//! We conceptually walk over the AST in reverse execution order. If we
+//! find a use of a variable, we add it to the set of live variables. If
 //! we find an assignment to a variable, we remove it from the set of live
-//! variables.  When we have to merge two flows, we take the union of
-//! those two flows---if the variable is live on both paths, we simply
-//! pick one id.  In the event of loops, we continue doing this until a
+//! variables. When we have to merge two flows, we take the union of
+//! those two flows -- if the variable is live on both paths, we simply
+//! pick one ID. In the event of loops, we continue doing this until a
 //! fixed point is reached.
 //!
 //! ## Checking initialization
 //!
-//! At the function entry point, all variables must be dead.  If this is
-//! not the case, we can report an error using the id found in the set of
+//! At the function entry point, all variables must be dead. If this is
+//! not the case, we can report an error using the ID found in the set of
 //! live variables, which identifies a use of the variable which is not
 //! dominated by an assignment.
 //!
@@ -38,20 +38,20 @@
 //!
 //! The actual implementation contains two (nested) walks over the AST.
 //! The outer walk has the job of building up the ir_maps instance for the
-//! enclosing function.  On the way down the tree, it identifies those AST
+//! enclosing function. On the way down the tree, it identifies those AST
 //! nodes and variable IDs that will be needed for the liveness analysis
-//! and assigns them contiguous IDs.  The liveness id for an AST node is
-//! called a `live_node` (it's a newtype'd u32) and the id for a variable
-//! is called a `variable` (another newtype'd u32).
+//! and assigns them contiguous IDs. The liveness ID for an AST node is
+//! called a `live_node` (it's a newtype'd `u32`) and the ID for a variable
+//! is called a `variable` (another newtype'd `u32`).
 //!
 //! On the way back up the tree, as we are about to exit from a function
-//! declaration we allocate a `liveness` instance.  Now that we know
+//! declaration we allocate a `liveness` instance. Now that we know
 //! precisely how many nodes and variables we need, we can allocate all
-//! the various arrays that we will need to precisely the right size.  We then
+//! the various arrays that we will need to precisely the right size. We then
 //! perform the actual propagation on the `liveness` instance.
 //!
 //! This propagation is encoded in the various `propagate_through_*()`
-//! methods.  It effectively does a reverse walk of the AST; whenever we
+//! methods. It effectively does a reverse walk of the AST; whenever we
 //! reach a loop node, we iterate until a fixed point is reached.
 //!
 //! ## The `RWU` struct
@@ -60,21 +60,21 @@
 //! variable `V` (these are encapsulated in the `RWU` struct):
 //!
 //! - `reader`: the `LiveNode` ID of some node which will read the value
-//!    that `V` holds on entry to `N`.  Formally: a node `M` such
+//!    that `V` holds on entry to `N`. Formally: a node `M` such
 //!    that there exists a path `P` from `N` to `M` where `P` does not
-//!    write `V`.  If the `reader` is `invalid_node()`, then the current
+//!    write `V`. If the `reader` is `invalid_node()`, then the current
 //!    value will never be read (the variable is dead, essentially).
 //!
 //! - `writer`: the `LiveNode` ID of some node which will write the
-//!    variable `V` and which is reachable from `N`.  Formally: a node `M`
+//!    variable `V` and which is reachable from `N`. Formally: a node `M`
 //!    such that there exists a path `P` from `N` to `M` and `M` writes
-//!    `V`.  If the `writer` is `invalid_node()`, then there is no writer
+//!    `V`. If the `writer` is `invalid_node()`, then there is no writer
 //!    of `V` that follows `N`.
 //!
-//! - `used`: a boolean value indicating whether `V` is *used*.  We
+//! - `used`: a boolean value indicating whether `V` is *used*. We
 //!   distinguish a *read* from a *use* in that a *use* is some read that
-//!   is not just used to generate a new value.  For example, `x += 1` is
-//!   a read but not a use.  This is used to generate better warnings.
+//!   is not just used to generate a new value. For example, `x += 1` is
+//!   a read but not a use. This is used to generate better warnings.
 //!
 //! ## Special Variables
 //!
@@ -87,7 +87,7 @@
 //! - `fallthrough_ln`: a live node that represents a fallthrough
 //!
 //! - `clean_exit_var`: a synthetic variable that is only 'read' from the
-//!   fallthrough node.  It is only live if the function could converge
+//!   fallthrough node. It is only live if the function could converge
 //!   via means other than an explicit `return` expression. That is, it is
 //!   only dead if the end of the function's block can never be reached.
 //!   It is the responsibility of typeck to ensure that there are no
@@ -97,14 +97,15 @@ use self::LoopKind::*;
 use self::LiveNodeKind::*;
 use self::VarKind::*;
 
-use hir::def::*;
-use hir::Node;
-use ty::{self, TyCtxt};
-use lint;
-use errors::Applicability;
-use util::nodemap::{NodeMap, HirIdMap, HirIdSet};
+use crate::hir::def::*;
+use crate::hir::Node;
+use crate::ty::{self, TyCtxt};
+use crate::ty::query::Providers;
+use crate::lint;
+use crate::util::nodemap::{NodeMap, HirIdMap, HirIdSet};
 
-use std::collections::VecDeque;
+use errors::Applicability;
+use std::collections::{BTreeMap, VecDeque};
 use std::{fmt, u32};
 use std::io::prelude::*;
 use std::io;
@@ -114,9 +115,10 @@ use syntax::ptr::P;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
 
-use hir::{Expr, HirId};
-use hir;
-use hir::intravisit::{self, Visitor, FnKind, NestedVisitorMap};
+use crate::hir;
+use crate::hir::{Expr, HirId};
+use crate::hir::def_id::DefId;
+use crate::hir::intravisit::{self, Visitor, FnKind, NestedVisitorMap};
 
 /// For use with `propagate_through_loop`.
 enum LoopKind<'a> {
@@ -179,9 +181,21 @@ impl<'a, 'tcx> Visitor<'tcx> for IrMaps<'a, 'tcx> {
     fn visit_arm(&mut self, a: &'tcx hir::Arm) { visit_arm(self, a); }
 }
 
+fn check_mod_liveness<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
+    tcx.hir().visit_item_likes_in_module(module_def_id, &mut IrMaps::new(tcx).as_deep_visitor());
+}
+
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
-    tcx.hir().krate().visit_all_item_likes(&mut IrMaps::new(tcx).as_deep_visitor());
-    tcx.sess.abort_if_errors();
+    for &module in tcx.hir().krate().modules.keys() {
+        tcx.ensure().check_mod_liveness(tcx.hir().local_def_id(module));
+    }
+}
+
+pub fn provide(providers: &mut Providers<'_>) {
+    *providers = Providers {
+        check_mod_liveness,
+        ..*providers
+    };
 }
 
 impl fmt::Debug for LiveNode {
@@ -391,9 +405,9 @@ fn add_from_pat<'a, 'tcx>(ir: &mut IrMaps<'a, 'tcx>, pat: &P<hir::Pat>) {
     let mut pats = VecDeque::new();
     pats.push_back(pat);
     while let Some(pat) = pats.pop_front() {
-        use hir::PatKind::*;
+        use crate::hir::PatKind::*;
         match pat.node {
-            Binding(_, _, _, ref inner_pat) => {
+            Binding(_, _, _, _, ref inner_pat) => {
                 pats.extend(inner_pat.iter());
             }
             Struct(_, ref fields, _) => {
@@ -911,17 +925,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     }
 
     fn compute(&mut self, body: &hir::Expr) -> LiveNode {
-        // if there is a `break` or `again` at the top level, then it's
-        // effectively a return---this only occurs in `for` loops,
-        // where the body is really a closure.
-
         debug!("compute: using id for body, {}", self.ir.tcx.hir().node_to_pretty_string(body.id));
 
-        let exit_ln = self.s.exit_ln;
-
-        self.break_ln.insert(body.id, exit_ln);
-        self.cont_ln.insert(body.id, exit_ln);
-
         // the fallthrough exit is only for those cases where we do not
         // explicitly return:
         let s = self.s;
@@ -956,46 +961,31 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     fn propagate_through_stmt(&mut self, stmt: &hir::Stmt, succ: LiveNode)
                               -> LiveNode {
         match stmt.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                self.propagate_through_decl(&decl, succ)
-            }
+            hir::StmtKind::Local(ref local) => {
+                // Note: we mark the variable as defined regardless of whether
+                // there is an initializer.  Initially I had thought to only mark
+                // the live variable as defined if it was initialized, and then we
+                // could check for uninit variables just by scanning what is live
+                // at the start of the function. But that doesn't work so well for
+                // immutable variables defined in a loop:
+                //     loop { let x; x = 5; }
+                // because the "assignment" loops back around and generates an error.
+                //
+                // So now we just check that variables defined w/o an
+                // initializer are not live at the point of their
+                // initialization, which is mildly more complex than checking
+                // once at the func header but otherwise equivalent.
 
-            hir::StmtKind::Expr(ref expr, _) | hir::StmtKind::Semi(ref expr, _) => {
-                self.propagate_through_expr(&expr, succ)
+                let succ = self.propagate_through_opt_expr(local.init.as_ref().map(|e| &**e), succ);
+                self.define_bindings_in_pat(&local.pat, succ)
             }
-        }
-    }
-
-    fn propagate_through_decl(&mut self, decl: &hir::Decl, succ: LiveNode)
-                              -> LiveNode {
-        match decl.node {
-            hir::DeclKind::Local(ref local) => {
-                self.propagate_through_local(&local, succ)
+            hir::StmtKind::Item(..) => succ,
+            hir::StmtKind::Expr(ref expr) | hir::StmtKind::Semi(ref expr) => {
+                self.propagate_through_expr(&expr, succ)
             }
-            hir::DeclKind::Item(_) => succ,
         }
     }
 
-    fn propagate_through_local(&mut self, local: &hir::Local, succ: LiveNode)
-                               -> LiveNode {
-        // Note: we mark the variable as defined regardless of whether
-        // there is an initializer.  Initially I had thought to only mark
-        // the live variable as defined if it was initialized, and then we
-        // could check for uninit variables just by scanning what is live
-        // at the start of the function. But that doesn't work so well for
-        // immutable variables defined in a loop:
-        //     loop { let x; x = 5; }
-        // because the "assignment" loops back around and generates an error.
-        //
-        // So now we just check that variables defined w/o an
-        // initializer are not live at the point of their
-        // initialization, which is mildly more complex than checking
-        // once at the func header but otherwise equivalent.
-
-        let succ = self.propagate_through_opt_expr(local.init.as_ref().map(|e| &**e), succ);
-        self.define_bindings_in_pat(&local.pat, succ)
-    }
-
     fn propagate_through_exprs(&mut self, exprs: &[Expr], succ: LiveNode)
                                -> LiveNode {
         exprs.iter().rev().fold(succ, |succ, expr| {
@@ -1024,19 +1014,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                 self.propagate_through_expr(&e, succ)
             }
 
-            hir::ExprKind::Closure(.., blk_id, _, _) => {
+            hir::ExprKind::Closure(..) => {
                 debug!("{} is an ExprKind::Closure",
                        self.ir.tcx.hir().node_to_pretty_string(expr.id));
 
-                // The next-node for a break is the successor of the entire
-                // loop. The next-node for a continue is the top of this loop.
-                let node = self.live_node(expr.hir_id, expr.span);
-
-                let break_ln = succ;
-                let cont_ln = node;
-                self.break_ln.insert(blk_id.node_id, break_ln);
-                self.cont_ln.insert(blk_id.node_id, cont_ln);
-
                 // the construction of a closure itself is not important,
                 // but we have to consider the closed over variables.
                 let caps = self.ir.capture_info_map.get(&expr.id).cloned().unwrap_or_else(||
@@ -1407,15 +1388,16 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         debug!("propagate_through_loop: using id for loop body {} {}",
                expr.id, self.ir.tcx.hir().node_to_pretty_string(body.id));
 
-        let break_ln = succ;
-        let cont_ln = ln;
-        self.break_ln.insert(expr.id, break_ln);
-        self.cont_ln.insert(expr.id, cont_ln);
+
+        self.break_ln.insert(expr.id, succ);
 
         let cond_ln = match kind {
             LoopLoop => ln,
             WhileLoop(ref cond) => self.propagate_through_expr(&cond, ln),
         };
+
+        self.cont_ln.insert(expr.id, cond_ln);
+
         let body_ln = self.propagate_through_block(body, cond_ln);
 
         // repeat until fixed point is reached:
@@ -1463,7 +1445,7 @@ fn check_local<'a, 'tcx>(this: &mut Liveness<'a, 'tcx>, local: &'tcx hir::Local)
         None => {
             this.pat_bindings(&local.pat, |this, ln, var, sp, id| {
                 let span = local.pat.simple_ident().map_or(sp, |ident| ident.span);
-                this.warn_about_unused(span, id, ln, var);
+                this.warn_about_unused(vec![span], id, ln, var);
             })
         }
     }
@@ -1472,12 +1454,29 @@ fn check_local<'a, 'tcx>(this: &mut Liveness<'a, 'tcx>, local: &'tcx hir::Local)
 }
 
 fn check_arm<'a, 'tcx>(this: &mut Liveness<'a, 'tcx>, arm: &'tcx hir::Arm) {
-    // only consider the first pattern; any later patterns must have
-    // the same bindings, and we also consider the first pattern to be
-    // the "authoritative" set of ids
-    this.arm_pats_bindings(arm.pats.first().map(|p| &**p), |this, ln, var, sp, id| {
-        this.warn_about_unused(sp, id, ln, var);
-    });
+    // Only consider the variable from the first pattern; any later patterns must have
+    // the same bindings, and we also consider the first pattern to be the "authoritative" set of
+    // ids. However, we should take the spans of variables with the same name from the later
+    // patterns so the suggestions to prefix with underscores will apply to those too.
+    let mut vars: BTreeMap<String, (LiveNode, Variable, HirId, Vec<Span>)> = Default::default();
+
+    for pat in &arm.pats {
+        this.arm_pats_bindings(Some(&*pat), |this, ln, var, sp, id| {
+            let name = this.ir.variable_name(var);
+            vars.entry(name)
+                .and_modify(|(.., spans)| {
+                    spans.push(sp);
+                })
+                .or_insert_with(|| {
+                    (ln, var, id, vec![sp])
+                });
+        });
+    }
+
+    for (_, (ln, var, id, spans)) in vars {
+        this.warn_about_unused(spans, id, ln, var);
+    }
+
     intravisit::walk_arm(this, arm);
 }
 
@@ -1568,7 +1567,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                 let var = self.variable(hir_id, sp);
                 // Ignore unused self.
                 if ident.name != keywords::SelfLower.name() {
-                    if !self.warn_about_unused(sp, hir_id, entry_ln, var) {
+                    if !self.warn_about_unused(vec![sp], hir_id, entry_ln, var) {
                         if self.live_on_entry(entry_ln, var).is_none() {
                             self.report_dead_assign(hir_id, sp, var, true);
                         }
@@ -1580,14 +1579,14 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
     fn warn_about_unused_or_dead_vars_in_pat(&mut self, pat: &hir::Pat) {
         self.pat_bindings(pat, |this, ln, var, sp, id| {
-            if !this.warn_about_unused(sp, id, ln, var) {
+            if !this.warn_about_unused(vec![sp], id, ln, var) {
                 this.warn_about_dead_assign(sp, id, ln, var);
             }
         })
     }
 
     fn warn_about_unused(&self,
-                         sp: Span,
+                         spans: Vec<Span>,
                          hir_id: HirId,
                          ln: LiveNode,
                          var: Variable)
@@ -1604,29 +1603,36 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                     self.assigned_on_exit(ln, var).is_some()
                 };
 
-                let suggest_underscore_msg = format!("consider using `_{}` instead", name);
-
                 if is_assigned {
-                    self.ir.tcx
-                        .lint_hir_note(lint::builtin::UNUSED_VARIABLES, hir_id, sp,
-                                       &format!("variable `{}` is assigned to, but never used",
-                                                name),
-                                       &suggest_underscore_msg);
+                    self.ir.tcx.lint_hir_note(
+                        lint::builtin::UNUSED_VARIABLES,
+                        hir_id,
+                        spans.clone(),
+                        &format!("variable `{}` is assigned to, but never used", name),
+                        &format!("consider using `_{}` instead", name),
+                    );
                 } else if name != "self" {
-                    let msg = format!("unused variable: `{}`", name);
-                    let mut err = self.ir.tcx
-                        .struct_span_lint_hir(lint::builtin::UNUSED_VARIABLES, hir_id, sp, &msg);
+                    let mut err = self.ir.tcx.struct_span_lint_hir(
+                        lint::builtin::UNUSED_VARIABLES,
+                        hir_id,
+                        spans.clone(),
+                        &format!("unused variable: `{}`", name),
+                    );
+
                     if self.ir.variable_is_shorthand(var) {
-                        err.span_suggestion_with_applicability(sp, "try ignoring the field",
-                                                               format!("{}: _", name),
-                                                               Applicability::MachineApplicable);
+                        err.multipart_suggestion(
+                            "try ignoring the field",
+                            spans.iter().map(|span| (*span, format!("{}: _", name))).collect(),
+                            Applicability::MachineApplicable
+                        );
                     } else {
-                        err.span_suggestion_short_with_applicability(
-                            sp, &suggest_underscore_msg,
-                            format!("_{}", name),
+                        err.multipart_suggestion(
+                            "consider prefixing with an underscore",
+                            spans.iter().map(|span| (*span, format!("_{}", name))).collect(),
                             Applicability::MachineApplicable,
                         );
                     }
+
                     err.emit()
                 }
             }
@@ -1636,11 +1642,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         }
     }
 
-    fn warn_about_dead_assign(&self,
-                              sp: Span,
-                              hir_id: HirId,
-                              ln: LiveNode,
-                              var: Variable) {
+    fn warn_about_dead_assign(&self, sp: Span, hir_id: HirId, ln: LiveNode, var: Variable) {
         if self.live_on_exit(ln, var).is_none() {
             self.report_dead_assign(hir_id, sp, var, false);
         }
diff --git a/src/librustc/middle/mem_categorization.rs b/src/librustc/middle/mem_categorization.rs
index 370f0d1a6c6d7..f65c09e31343c 100644
--- a/src/librustc/middle/mem_categorization.rs
+++ b/src/librustc/middle/mem_categorization.rs
@@ -3,7 +3,7 @@
 //! The job of the categorization module is to analyze an expression to
 //! determine what kind of memory is used in evaluating it (for example,
 //! where dereferences occur and what kind of pointer is dereferenced;
-//! whether the memory is mutable; etc)
+//! whether the memory is mutable, etc.).
 //!
 //! Categorization effectively transforms all of our expressions into
 //! expressions of the following forms (the actual enum has many more
@@ -16,21 +16,21 @@
 //!       | E.comp    // access to an interior component
 //!
 //! Imagine a routine ToAddr(Expr) that evaluates an expression and returns an
-//! address where the result is to be found.  If Expr is a place, then this
-//! is the address of the place.  If Expr is an rvalue, this is the address of
+//! address where the result is to be found. If Expr is a place, then this
+//! is the address of the place. If `Expr` is an rvalue, this is the address of
 //! some temporary spot in memory where the result is stored.
 //!
-//! Now, cat_expr() classifies the expression Expr and the address A=ToAddr(Expr)
+//! Now, `cat_expr()` classifies the expression `Expr` and the address `A = ToAddr(Expr)`
 //! as follows:
 //!
-//! - cat: what kind of expression was this?  This is a subset of the
+//! - `cat`: what kind of expression was this? This is a subset of the
 //!   full expression forms which only includes those that we care about
 //!   for the purpose of the analysis.
-//! - mutbl: mutability of the address A
-//! - ty: the type of data found at the address A
+//! - `mutbl`: mutability of the address `A`.
+//! - `ty`: the type of data found at the address `A`.
 //!
 //! The resulting categorization tree differs somewhat from the expressions
-//! themselves.  For example, auto-derefs are explicit.  Also, an index a[b] is
+//! themselves. For example, auto-derefs are explicit. Also, an index a[b] is
 //! decomposed into two operations: a dereference to reach the array data and
 //! then an index to jump forward to the relevant item.
 //!
@@ -58,19 +58,19 @@ pub use self::Note::*;
 
 use self::Aliasability::*;
 
-use middle::region;
-use hir::def_id::{DefId, LocalDefId};
-use hir::Node;
-use infer::InferCtxt;
-use hir::def::{Def, CtorKind};
-use ty::adjustment;
-use ty::{self, Ty, TyCtxt};
-use ty::fold::TypeFoldable;
-use ty::layout::VariantIdx;
-
-use hir::{MutImmutable, MutMutable, PatKind};
-use hir::pat_util::EnumerateAndAdjustIterator;
-use hir;
+use crate::middle::region;
+use crate::hir::def_id::{DefId, LocalDefId};
+use crate::hir::Node;
+use crate::infer::InferCtxt;
+use crate::hir::def::{Def, CtorKind};
+use crate::ty::adjustment;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::layout::VariantIdx;
+
+use crate::hir::{MutImmutable, MutMutable, PatKind};
+use crate::hir::pat_util::EnumerateAndAdjustIterator;
+use crate::hir;
 use syntax::ast::{self, Name};
 use syntax_pos::Span;
 
@@ -80,7 +80,7 @@ use std::hash::{Hash, Hasher};
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::indexed_vec::Idx;
 use std::rc::Rc;
-use util::nodemap::ItemLocalSet;
+use crate::util::nodemap::ItemLocalSet;
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum Categorization<'tcx> {
@@ -174,7 +174,7 @@ pub enum Note {
 // which the value is stored.
 //
 // *WARNING* The field `cmt.type` is NOT necessarily the same as the
-// result of `node_id_to_type(cmt.id)`.
+// result of `node_type(cmt.id)`.
 //
 // (FIXME: rewrite the following comment given that `@x` managed
 // pointers have been obsolete for quite some time.)
@@ -497,7 +497,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                    hir_id: hir::HirId)
                    -> McResult<Ty<'tcx>> {
         self.resolve_type_vars_or_error(hir_id,
-                                        self.tables.node_id_to_type_opt(hir_id))
+                                        self.tables.node_type_opt(hir_id))
     }
 
     pub fn expr_ty(&self, expr: &hir::Expr) -> McResult<Ty<'tcx>> {
@@ -704,7 +704,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                hir_id, expr_ty, def);
 
         match def {
-            Def::StructCtor(..) | Def::VariantCtor(..) | Def::Const(..) |
+            Def::StructCtor(..) | Def::VariantCtor(..) | Def::Const(..) | Def::ConstParam(..) |
             Def::AssociatedConst(..) | Def::Fn(..) | Def::Method(..) | Def::SelfCtor(..) => {
                 Ok(self.cat_rvalue_node(hir_id, span, expr_ty))
             }
@@ -1311,12 +1311,12 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                     Def::Err => {
                         debug!("access to unresolvable pattern {:?}", pat);
                         return Err(())
-                    },
+                    }
                     Def::Variant(variant_did) |
                     Def::VariantCtor(variant_did, ..) => {
                         self.cat_downcast_if_needed(pat, cmt, variant_did)
-                    },
-                    _ => cmt
+                    }
+                    _ => cmt,
                 };
 
                 for fp in field_pats {
@@ -1347,7 +1347,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
                 }
             }
 
-                PatKind::Box(ref subpat) | PatKind::Ref(ref subpat, _) => {
+            PatKind::Box(ref subpat) | PatKind::Ref(ref subpat, _) => {
                 // box p1, &p1, &mut p1.  we can ignore the mutability of
                 // PatKind::Ref since that information is already contained
                 // in the type.
diff --git a/src/librustc/middle/privacy.rs b/src/librustc/middle/privacy.rs
index 7736d5e795ea0..1655d8356a5a7 100644
--- a/src/librustc/middle/privacy.rs
+++ b/src/librustc/middle/privacy.rs
@@ -2,7 +2,7 @@
 //! outside their scopes. This pass will also generate a set of exported items
 //! which are available for use externally when compiled as a library.
 
-use util::nodemap::{DefIdSet, FxHashMap};
+use crate::util::nodemap::{DefIdSet, FxHashMap};
 
 use std::hash::Hash;
 use std::fmt;
@@ -11,16 +11,16 @@ use syntax::ast::NodeId;
 // Accessibility levels, sorted in ascending order
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum AccessLevel {
-    // Superset of Reachable used to mark impl Trait items.
+    /// Superset of `AccessLevel::Reachable` used to mark impl Trait items.
     ReachableFromImplTrait,
-    // Exported items + items participating in various kinds of public interfaces,
-    // but not directly nameable. For example, if function `fn f() -> T {...}` is
-    // public, then type `T` is reachable. Its values can be obtained by other crates
-    // even if the type itself is not nameable.
+    /// Exported items + items participating in various kinds of public interfaces,
+    /// but not directly nameable. For example, if function `fn f() -> T {...}` is
+    /// public, then type `T` is reachable. Its values can be obtained by other crates
+    /// even if the type itself is not nameable.
     Reachable,
-    // Public items + items accessible to other crates with help of `pub use` re-exports
+    /// Public items + items accessible to other crates with help of `pub use` re-exports
     Exported,
-    // Items accessible to other crates directly, without help of re-exports
+    /// Items accessible to other crates directly, without help of re-exports
     Public,
 }
 
@@ -31,12 +31,17 @@ pub struct AccessLevels<Id = NodeId> {
 }
 
 impl<Id: Hash + Eq> AccessLevels<Id> {
+    /// See `AccessLevel::Reachable`.
     pub fn is_reachable(&self, id: Id) -> bool {
         self.map.get(&id) >= Some(&AccessLevel::Reachable)
     }
+
+    /// See `AccessLevel::Exported`.
     pub fn is_exported(&self, id: Id) -> bool {
         self.map.get(&id) >= Some(&AccessLevel::Exported)
     }
+
+    /// See `AccessLevel::Public`.
     pub fn is_public(&self, id: Id) -> bool {
         self.map.get(&id) >= Some(&AccessLevel::Public)
     }
diff --git a/src/librustc/middle/reachable.rs b/src/librustc/middle/reachable.rs
index 10deca836fff3..0562fddb2b523 100644
--- a/src/librustc/middle/reachable.rs
+++ b/src/librustc/middle/reachable.rs
@@ -5,24 +5,24 @@
 // makes all other generics or inline functions that it references
 // reachable as well.
 
-use hir::{CodegenFnAttrs, CodegenFnAttrFlags};
-use hir::Node;
-use hir::def::Def;
-use hir::def_id::{DefId, CrateNum};
+use crate::hir::{CodegenFnAttrs, CodegenFnAttrFlags};
+use crate::hir::Node;
+use crate::hir::def::Def;
+use crate::hir::def_id::{DefId, CrateNum};
 use rustc_data_structures::sync::Lrc;
-use ty::{self, TyCtxt};
-use ty::query::Providers;
-use middle::privacy;
-use session::config;
-use util::nodemap::{NodeSet, FxHashSet};
+use crate::ty::{self, TyCtxt};
+use crate::ty::query::Providers;
+use crate::middle::privacy;
+use crate::session::config;
+use crate::util::nodemap::{NodeSet, FxHashSet};
 
 use rustc_target::spec::abi::Abi;
 use syntax::ast;
-use hir;
-use hir::def_id::LOCAL_CRATE;
-use hir::intravisit::{Visitor, NestedVisitorMap};
-use hir::itemlikevisit::ItemLikeVisitor;
-use hir::intravisit;
+use crate::hir;
+use crate::hir::def_id::LOCAL_CRATE;
+use crate::hir::intravisit::{Visitor, NestedVisitorMap};
+use crate::hir::itemlikevisit::ItemLikeVisitor;
+use crate::hir::intravisit;
 
 // Returns true if the given item must be inlined because it may be
 // monomorphized or it was marked with `#[inline]`. This will only return
@@ -177,8 +177,8 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
                             // Check the impl. If the generics on the self
                             // type of the impl require inlining, this method
                             // does too.
-                            let impl_node_id = self.tcx.hir().as_local_node_id(impl_did).unwrap();
-                            match self.tcx.hir().expect_item(impl_node_id).node {
+                            let impl_hir_id = self.tcx.hir().as_local_hir_id(impl_did).unwrap();
+                            match self.tcx.hir().expect_item_by_hir_id(impl_hir_id).node {
                                 hir::ItemKind::Impl(..) => {
                                     let generics = self.tcx.generics_of(impl_did);
                                     generics.requires_monomorphization(self.tcx)
@@ -315,8 +315,11 @@ impl<'a, 'tcx> ReachableContext<'a, 'tcx> {
             Node::Ty(_) |
             Node::MacroDef(_) => {}
             _ => {
-                bug!("found unexpected thingy in worklist: {}",
-                     self.tcx.hir().node_to_string(search_item))
+                bug!(
+                    "found unexpected node kind in worklist: {} ({:?})",
+                    self.tcx.hir().node_to_string(search_item),
+                    node,
+                );
             }
         }
     }
diff --git a/src/librustc/middle/recursion_limit.rs b/src/librustc/middle/recursion_limit.rs
index 1eabd7f59e689..ea077220e0be3 100644
--- a/src/librustc/middle/recursion_limit.rs
+++ b/src/librustc/middle/recursion_limit.rs
@@ -5,7 +5,7 @@
 // this via an attribute on the crate like `#![recursion_limit="22"]`. This pass
 // just peeks and looks for that attribute.
 
-use session::Session;
+use crate::session::Session;
 use syntax::ast;
 
 use rustc_data_structures::sync::Once;
diff --git a/src/librustc/middle/region.rs b/src/librustc/middle/region.rs
index ce2a348950622..fd188b33d7e1f 100644
--- a/src/librustc/middle/region.rs
+++ b/src/librustc/middle/region.rs
@@ -6,9 +6,9 @@
 //!
 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/borrowck.html
 
-use ich::{StableHashingContext, NodeIdHashingMode};
-use util::nodemap::{FxHashMap, FxHashSet};
-use ty;
+use crate::ich::{StableHashingContext, NodeIdHashingMode};
+use crate::util::nodemap::{FxHashMap, FxHashSet};
+use crate::ty;
 
 use std::mem;
 use std::fmt;
@@ -16,14 +16,14 @@ use rustc_data_structures::sync::Lrc;
 use syntax::source_map;
 use syntax::ast;
 use syntax_pos::{Span, DUMMY_SP};
-use ty::TyCtxt;
-use ty::query::Providers;
-
-use hir;
-use hir::Node;
-use hir::def_id::DefId;
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
-use hir::{Block, Arm, Pat, PatKind, Stmt, Expr, Local};
+use crate::ty::TyCtxt;
+use crate::ty::query::Providers;
+
+use crate::hir;
+use crate::hir::Node;
+use crate::hir::def_id::DefId;
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::hir::{Block, Arm, Pat, PatKind, Stmt, Expr, Local};
 use rustc_data_structures::indexed_vec::Idx;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
@@ -85,11 +85,11 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
 /// values live long enough; phrased another way, the starting point
 /// of each range is not really the important thing in the above
 /// picture, but rather the ending point.
-///
-/// FIXME (pnkfelix): This currently derives `PartialOrd` and `Ord` to
-/// placate the same deriving in `ty::FreeRegion`, but we may want to
-/// actually attach a more meaningful ordering to scopes than the one
-/// generated via deriving here.
+//
+// FIXME(pnkfelix): this currently derives `PartialOrd` and `Ord` to
+// placate the same deriving in `ty::FreeRegion`, but we may want to
+// actually attach a more meaningful ordering to scopes than the one
+// generated via deriving here.
 #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Copy, RustcEncodable, RustcDecodable)]
 pub struct Scope {
     pub id: hir::ItemLocalId,
@@ -140,27 +140,27 @@ pub enum ScopeData {
 ///
 /// For example, given `{ let (a, b) = EXPR_1; let c = EXPR_2; ... }`:
 ///
-/// * the subscope with `first_statement_index == 0` is scope of both
+/// * The subscope with `first_statement_index == 0` is scope of both
 ///   `a` and `b`; it does not include EXPR_1, but does include
 ///   everything after that first `let`. (If you want a scope that
 ///   includes EXPR_1 as well, then do not use `Scope::Remainder`,
 ///   but instead another `Scope` that encompasses the whole block,
 ///   e.g., `Scope::Node`.
 ///
-/// * the subscope with `first_statement_index == 1` is scope of `c`,
+/// * The subscope with `first_statement_index == 1` is scope of `c`,
 ///   and thus does not include EXPR_2, but covers the `...`.
 
 newtype_index! {
     pub struct FirstStatementIndex { .. }
 }
 
-impl_stable_hash_for!(struct ::middle::region::FirstStatementIndex { private });
+impl_stable_hash_for!(struct crate::middle::region::FirstStatementIndex { private });
 
 // compilation error if size of `ScopeData` is not the same as a `u32`
 static_assert!(ASSERT_SCOPE_DATA: mem::size_of::<ScopeData>() == 4);
 
 impl Scope {
-    /// Returns a item-local id associated with this scope.
+    /// Returns a item-local ID associated with this scope.
     ///
     /// N.B., likely to be replaced as API is refined; e.g., pnkfelix
     /// anticipates `fn entry_node_id` and `fn each_exit_node_id`.
@@ -180,8 +180,8 @@ impl Scope {
         }
     }
 
-    /// Returns the span of this Scope.  Note that in general the
-    /// returned span may not correspond to the span of any node id in
+    /// Returns the span of this `Scope`. Note that in general the
+    /// returned span may not correspond to the span of any `NodeId` in
     /// the AST.
     pub fn span(&self, tcx: TyCtxt<'_, '_, '_>, scope_tree: &ScopeTree) -> Span {
         let node_id = self.node_id(tcx, scope_tree);
@@ -225,19 +225,19 @@ pub struct ScopeTree {
     /// have lifetime parameters free in this body.
     root_parent: Option<ast::NodeId>,
 
-    /// `parent_map` maps from a scope id to the enclosing scope id;
+    /// `parent_map` maps from a scope ID to the enclosing scope id;
     /// this is usually corresponding to the lexical nesting, though
     /// in the case of closures the parent scope is the innermost
     /// conditional expression or repeating block. (Note that the
-    /// enclosing scope id for the block associated with a closure is
+    /// enclosing scope ID for the block associated with a closure is
     /// the closure itself.)
     parent_map: FxHashMap<Scope, (Scope, ScopeDepth)>,
 
-    /// `var_map` maps from a variable or binding id to the block in
+    /// `var_map` maps from a variable or binding ID to the block in
     /// which that variable is declared.
     var_map: FxHashMap<hir::ItemLocalId, Scope>,
 
-    /// maps from a node-id to the associated destruction scope (if any)
+    /// maps from a `NodeId` to the associated destruction scope (if any)
     destruction_scopes: FxHashMap<hir::ItemLocalId, Scope>,
 
     /// `rvalue_scopes` includes entries for those expressions whose cleanup scope is
@@ -252,8 +252,8 @@ pub struct ScopeTree {
 
     /// Encodes the hierarchy of fn bodies. Every fn body (including
     /// closures) forms its own distinct region hierarchy, rooted in
-    /// the block that is the fn body. This map points from the id of
-    /// that root block to the id of the root block for the enclosing
+    /// the block that is the fn body. This map points from the ID of
+    /// that root block to the ID of the root block for the enclosing
     /// fn, if any. Thus the map structures the fn bodies into a
     /// hierarchy based on their lexical mapping. This is used to
     /// handle the relationships between regions in a fn and in a
@@ -382,7 +382,7 @@ struct RegionResolutionVisitor<'a, 'tcx: 'a> {
     /// upon exiting the parent scope, we cannot statically know how
     /// many times the expression executed, and thus if the expression
     /// creates temporaries we cannot know statically how many such
-    /// temporaries we would have to cleanup. Therefore we ensure that
+    /// temporaries we would have to cleanup. Therefore, we ensure that
     /// the temporaries never outlast the conditional/repeating
     /// expression, preventing the need for dynamic checks and/or
     /// arbitrary amounts of stack space. Terminating scopes end
@@ -465,7 +465,7 @@ impl<'tcx> ScopeTree {
     }
 
     /// Records that `sub_closure` is defined within `sup_closure`. These ids
-    /// should be the id of the block that is the fn body, which is
+    /// should be the ID of the block that is the fn body, which is
     /// also the root of the region hierarchy for that fn.
     fn record_closure_parent(&mut self,
                              sub_closure: hir::ItemLocalId,
@@ -551,8 +551,8 @@ impl<'tcx> ScopeTree {
         self.is_subscope_of(scope2, scope1)
     }
 
-    /// Returns true if `subscope` is equal to or is lexically nested inside `superscope` and false
-    /// otherwise.
+    /// Returns `true` if `subscope` is equal to or is lexically nested inside `superscope`, and
+    /// `false` otherwise.
     pub fn is_subscope_of(&self,
                           subscope: Scope,
                           superscope: Scope)
@@ -575,7 +575,7 @@ impl<'tcx> ScopeTree {
         return true;
     }
 
-    /// Returns the id of the innermost containing body
+    /// Returns the ID of the innermost containing body
     pub fn containing_body(&self, mut scope: Scope) -> Option<hir::ItemLocalId> {
         loop {
             if let ScopeData::CallSite = scope.data {
@@ -586,7 +586,7 @@ impl<'tcx> ScopeTree {
         }
     }
 
-    /// Finds the nearest common ancestor of two scopes.  That is, finds the
+    /// Finds the nearest common ancestor of two scopes. That is, finds the
     /// smallest scope which is greater than or equal to both `scope_a` and
     /// `scope_b`.
     pub fn nearest_common_ancestor(&self, scope_a: Scope, scope_b: Scope) -> Scope {
@@ -784,20 +784,25 @@ fn resolve_block<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>, blk:
         // index information.)
 
         for (i, statement) in blk.stmts.iter().enumerate() {
-            if let hir::StmtKind::Decl(..) = statement.node {
-                // Each StmtKind::Decl introduces a subscope for bindings
-                // introduced by the declaration; this subscope covers
-                // a suffix of the block . Each subscope in a block
-                // has the previous subscope in the block as a parent,
-                // except for the first such subscope, which has the
-                // block itself as a parent.
-                visitor.enter_scope(
-                    Scope {
-                        id: blk.hir_id.local_id,
-                        data: ScopeData::Remainder(FirstStatementIndex::new(i))
-                    }
-                );
-                visitor.cx.var_parent = visitor.cx.parent;
+            match statement.node {
+                hir::StmtKind::Local(..) |
+                hir::StmtKind::Item(..) => {
+                    // Each declaration introduces a subscope for bindings
+                    // introduced by the declaration; this subscope covers a
+                    // suffix of the block. Each subscope in a block has the
+                    // previous subscope in the block as a parent, except for
+                    // the first such subscope, which has the block itself as a
+                    // parent.
+                    visitor.enter_scope(
+                        Scope {
+                            id: blk.hir_id.local_id,
+                            data: ScopeData::Remainder(FirstStatementIndex::new(i))
+                        }
+                    );
+                    visitor.cx.var_parent = visitor.cx.parent;
+                }
+                hir::StmtKind::Expr(..) |
+                hir::StmtKind::Semi(..) => {}
             }
             visitor.visit_stmt(statement)
         }
@@ -835,7 +840,7 @@ fn resolve_pat<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>, pat: &
 }
 
 fn resolve_stmt<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>, stmt: &'tcx hir::Stmt) {
-    let stmt_id = visitor.tcx.hir().node_to_hir_id(stmt.node.id()).local_id;
+    let stmt_id = stmt.hir_id.local_id;
     debug!("resolve_stmt(stmt.id={:?})", stmt_id);
 
     // Every statement will clean up the temporaries created during
@@ -1046,7 +1051,7 @@ fn resolve_local<'a, 'tcx>(visitor: &mut RegionResolutionVisitor<'a, 'tcx>,
         visitor.visit_pat(pat);
     }
 
-    /// True if `pat` match the `P&` nonterminal:
+    /// Returns `true` if `pat` match the `P&` non-terminal.
     ///
     ///     P& = ref X
     ///        | StructName { ..., P&, ... }
@@ -1263,8 +1268,8 @@ impl<'a, 'tcx> Visitor<'tcx> for RegionResolutionVisitor<'a, 'tcx> {
 
         // The body of the every fn is a root scope.
         self.cx.parent = self.cx.var_parent;
-        if let hir::BodyOwnerKind::Fn = self.tcx.hir().body_owner_kind(owner_id) {
-            self.visit_expr(&body.value);
+        if self.tcx.hir().body_owner_kind(owner_id).is_fn_or_closure() {
+            self.visit_expr(&body.value)
         } else {
             // Only functions have an outer terminating (drop) scope, while
             // temporaries in constant initializers may be 'static, but only
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 2d3653464d538..08da74f47d450 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -3,18 +3,19 @@
 //! Name resolution for lifetimes follows MUCH simpler rules than the
 //! full resolve. For example, lifetime names are never exported or
 //! used between functions, and they operate in a purely top-down
-//! way. Therefore we break lifetime name resolution into a separate pass.
+//! way. Therefore, we break lifetime name resolution into a separate pass.
 
-use hir::def::Def;
-use hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
-use hir::map::Map;
-use hir::{GenericArg, GenericParam, ItemLocalId, LifetimeName, Node, ParamName};
-use ty::{self, DefIdTree, GenericParamDefKind, TyCtxt};
+use crate::hir::def::Def;
+use crate::hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
+use crate::hir::map::Map;
+use crate::hir::{GenericArg, GenericParam, ItemLocalId, LifetimeName, Node, ParamName};
+use crate::ty::{self, DefIdTree, GenericParamDefKind, TyCtxt};
 
+use crate::rustc::lint;
+use crate::session::Session;
+use crate::util::nodemap::{DefIdMap, FxHashMap, FxHashSet, NodeMap, NodeSet};
 use errors::{Applicability, DiagnosticBuilder};
-use rustc::lint;
 use rustc_data_structures::sync::Lrc;
-use session::Session;
 use std::borrow::Cow;
 use std::cell::Cell;
 use std::mem::replace;
@@ -23,10 +24,9 @@ use syntax::attr;
 use syntax::ptr::P;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
-use util::nodemap::{DefIdMap, FxHashMap, FxHashSet, NodeMap, NodeSet};
 
-use hir::intravisit::{self, NestedVisitorMap, Visitor};
-use hir::{self, GenericParamKind, LifetimeParamKind};
+use crate::hir::intravisit::{self, NestedVisitorMap, Visitor};
+use crate::hir::{self, GenericParamKind, LifetimeParamKind};
 
 /// The origin of a named lifetime definition.
 ///
@@ -207,7 +207,7 @@ struct NamedRegionMap {
     pub object_lifetime_defaults: NodeMap<Vec<ObjectLifetimeDefault>>,
 }
 
-/// See `NamedRegionMap`.
+/// See [`NamedRegionMap`].
 #[derive(Default)]
 pub struct ResolveLifetimes {
     defs: FxHashMap<LocalDefId, Lrc<FxHashMap<ItemLocalId, Region>>>,
@@ -216,7 +216,7 @@ pub struct ResolveLifetimes {
         FxHashMap<LocalDefId, Lrc<FxHashMap<ItemLocalId, Lrc<Vec<ObjectLifetimeDefault>>>>>,
 }
 
-impl_stable_hash_for!(struct ::middle::resolve_lifetime::ResolveLifetimes {
+impl_stable_hash_for!(struct crate::middle::resolve_lifetime::ResolveLifetimes {
     defs,
     late_bound,
     object_lifetime_defaults
@@ -227,21 +227,19 @@ struct LifetimeContext<'a, 'tcx: 'a> {
     map: &'a mut NamedRegionMap,
     scope: ScopeRef<'a>,
 
-    /// Deep breath. Our representation for poly trait refs contains a single
+    /// This is slightly complicated. Our representation for poly-trait-refs contains a single
     /// binder and thus we only allow a single level of quantification. However,
     /// the syntax of Rust permits quantification in two places, e.g., `T: for <'a> Foo<'a>`
-    /// and `for <'a, 'b> &'b T: Foo<'a>`. In order to get the de Bruijn indices
+    /// and `for <'a, 'b> &'b T: Foo<'a>`. In order to get the De Bruijn indices
     /// correct when representing these constraints, we should only introduce one
     /// scope. However, we want to support both locations for the quantifier and
     /// during lifetime resolution we want precise information (so we can't
     /// desugar in an earlier phase).
     ///
-    /// SO, if we encounter a quantifier at the outer scope, we set
-    /// trait_ref_hack to true (and introduce a scope), and then if we encounter
-    /// a quantifier at the inner scope, we error. If trait_ref_hack is false,
+    /// So, if we encounter a quantifier at the outer scope, we set
+    /// `trait_ref_hack` to `true` (and introduce a scope), and then if we encounter
+    /// a quantifier at the inner scope, we error. If `trait_ref_hack` is `false`,
     /// then we introduce the scope at the inner quantifier.
-    ///
-    /// I'm sorry.
     trait_ref_hack: bool,
 
     /// Used to disallow the use of in-band lifetimes in `fn` or `Fn` syntax.
@@ -529,23 +527,20 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 } else {
                     0
                 };
-                let mut type_count = 0;
-                let lifetimes = generics
-                    .params
-                    .iter()
-                    .filter_map(|param| match param.kind {
-                        GenericParamKind::Lifetime { .. } => {
-                            Some(Region::early(&self.tcx.hir(), &mut index, param))
-                        }
-                        GenericParamKind::Type { .. } => {
-                            type_count += 1;
-                            None
-                        }
-                    })
-                    .collect();
+                let mut non_lifetime_count = 0;
+                let lifetimes = generics.params.iter().filter_map(|param| match param.kind {
+                    GenericParamKind::Lifetime { .. } => {
+                        Some(Region::early(&self.tcx.hir(), &mut index, param))
+                    }
+                    GenericParamKind::Type { .. } |
+                    GenericParamKind::Const { .. } => {
+                        non_lifetime_count += 1;
+                        None
+                    }
+                }).collect();
                 let scope = Scope::Binder {
                     lifetimes,
-                    next_early_index: index + type_count,
+                    next_early_index: index + non_lifetime_count,
                     abstract_type_parent: true,
                     track_lifetime_uses,
                     s: ROOT_SCOPE,
@@ -710,7 +705,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
 
                 let mut elision = None;
                 let mut lifetimes = FxHashMap::default();
-                let mut type_count = 0;
+                let mut non_lifetime_count = 0;
                 for param in &generics.params {
                     match param.kind {
                         GenericParamKind::Lifetime { .. } => {
@@ -727,12 +722,13 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                                 lifetimes.insert(name, reg);
                             }
                         }
-                        GenericParamKind::Type { .. } => {
-                            type_count += 1;
+                        GenericParamKind::Type { .. } |
+                        GenericParamKind::Const { .. } => {
+                            non_lifetime_count += 1;
                         }
                     }
                 }
-                let next_early_index = index + type_count;
+                let next_early_index = index + non_lifetime_count;
 
                 if let Some(elision_region) = elision {
                     let scope = Scope::Elision {
@@ -790,23 +786,20 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 let generics = &trait_item.generics;
                 let mut index = self.next_early_index();
                 debug!("visit_ty: index = {}", index);
-                let mut type_count = 0;
-                let lifetimes = generics
-                    .params
-                    .iter()
-                    .filter_map(|param| match param.kind {
-                        GenericParamKind::Lifetime { .. } => {
-                            Some(Region::early(&self.tcx.hir(), &mut index, param))
-                        }
-                        GenericParamKind::Type { .. } => {
-                            type_count += 1;
-                            None
-                        }
-                    })
-                    .collect();
+                let mut non_lifetime_count = 0;
+                let lifetimes = generics.params.iter().filter_map(|param| match param.kind {
+                    GenericParamKind::Lifetime { .. } => {
+                        Some(Region::early(&self.tcx.hir(), &mut index, param))
+                    }
+                    GenericParamKind::Type { .. } |
+                    GenericParamKind::Const { .. } => {
+                        non_lifetime_count += 1;
+                        None
+                    }
+                }).collect();
                 let scope = Scope::Binder {
                     lifetimes,
-                    next_early_index: index + type_count,
+                    next_early_index: index + non_lifetime_count,
                     s: self.scope,
                     track_lifetime_uses: true,
                     abstract_type_parent: true,
@@ -844,24 +837,21 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
             Type(ref ty) => {
                 let generics = &impl_item.generics;
                 let mut index = self.next_early_index();
-                let mut next_early_index = index;
+                let mut non_lifetime_count = 0;
                 debug!("visit_ty: index = {}", index);
-                let lifetimes = generics
-                    .params
-                    .iter()
-                    .filter_map(|param| match param.kind {
-                        GenericParamKind::Lifetime { .. } => {
-                            Some(Region::early(&self.tcx.hir(), &mut index, param))
-                        }
-                        GenericParamKind::Type { .. } => {
-                            next_early_index += 1;
-                            None
-                        }
-                    })
-                    .collect();
+                let lifetimes = generics.params.iter().filter_map(|param| match param.kind {
+                    GenericParamKind::Lifetime { .. } => {
+                        Some(Region::early(&self.tcx.hir(), &mut index, param))
+                    }
+                    GenericParamKind::Const { .. } |
+                    GenericParamKind::Type { .. } => {
+                        non_lifetime_count += 1;
+                        None
+                    }
+                }).collect();
                 let scope = Scope::Binder {
                     lifetimes,
-                    next_early_index,
+                    next_early_index: index + non_lifetime_count,
                     s: self.scope,
                     track_lifetime_uses: true,
                     abstract_type_parent: true,
@@ -876,19 +866,19 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 let mut index = self.next_early_index();
                 let mut next_early_index = index;
                 debug!("visit_ty: index = {}", index);
-                let lifetimes = generics
-                    .params
-                    .iter()
-                    .filter_map(|param| match param.kind {
-                        GenericParamKind::Lifetime { .. } => {
-                            Some(Region::early(&self.tcx.hir(), &mut index, param))
-                        }
-                        GenericParamKind::Type { .. } => {
-                            next_early_index += 1;
-                            None
-                        }
-                    })
-                    .collect();
+                let lifetimes = generics.params.iter().filter_map(|param| match param.kind {
+                    GenericParamKind::Lifetime { .. } => {
+                        Some(Region::early(&self.tcx.hir(), &mut index, param))
+                    }
+                    GenericParamKind::Type { .. } => {
+                        next_early_index += 1;
+                        None
+                    }
+                    GenericParamKind::Const { .. } => {
+                        next_early_index += 1;
+                        None
+                    }
+                }).collect();
 
                 let scope = Scope::Binder {
                     lifetimes,
@@ -952,6 +942,10 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         self.visit_ty(&ty);
                     }
                 }
+                GenericParamKind::Const { ref ty, .. } => {
+                    walk_list!(self, visit_param_bound, &param.bounds);
+                    self.visit_ty(&ty);
+                }
             }
         }
         for predicate in &generics.where_clause.predicates {
@@ -1248,12 +1242,12 @@ fn extract_labels(ctxt: &mut LifetimeContext<'_, '_>, body: &hir::Body) {
                 } => {
                     // FIXME (#24278): non-hygienic comparison
                     if let Some(def) = lifetimes.get(&hir::ParamName::Plain(label.modern())) {
-                        let node_id = tcx.hir().as_local_node_id(def.id().unwrap()).unwrap();
+                        let hir_id = tcx.hir().as_local_hir_id(def.id().unwrap()).unwrap();
 
                         signal_shadowing_problem(
                             tcx,
                             label.name,
-                            original_lifetime(tcx.hir().span(node_id)),
+                            original_lifetime(tcx.hir().span_by_hir_id(hir_id)),
                             shadower_label(label.span),
                         );
                         return;
@@ -1397,6 +1391,10 @@ fn object_lifetime_defaults_for_item(
                     Set1::Many => Set1::Many,
                 })
             }
+            GenericParamKind::Const { .. } => {
+                // Generic consts don't impose any constraints.
+                None
+            }
         })
         .collect()
 }
@@ -1526,14 +1524,14 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             // place ("start at" because the latter includes trailing
             // whitespace), then this is an in-band lifetime
             if decl_span.shrink_to_lo() == use_span.shrink_to_lo() {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     use_span,
                     "elide the single-use lifetime",
                     String::new(),
                     Applicability::MachineApplicable,
                 );
             } else {
-                err.multipart_suggestion_with_applicability(
+                err.multipart_suggestion(
                     "elide the single-use lifetime",
                     vec![(decl_span, String::new()), (use_span, String::new())],
                     Applicability::MachineApplicable,
@@ -1644,7 +1642,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                             if let Some(generics) = self.tcx.hir().get_generics(parent_def_id) {
                                 let unused_lt_span = self.lifetime_deletion_span(name, generics);
                                 if let Some(span) = unused_lt_span {
-                                    err.span_suggestion_with_applicability(
+                                    err.span_suggestion(
                                         span,
                                         "elide the unused lifetime",
                                         String::new(),
@@ -1676,7 +1674,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
     /// If early bound lifetimes are present, we separate them into their own list (and likewise
     /// for late bound). They will be numbered sequentially, starting from the lowest index that is
     /// already in scope (for a fn item, that will be 0, but for a method it might not be). Late
-    /// bound lifetimes are resolved by name and associated with a binder id (`binder_id`), so the
+    /// bound lifetimes are resolved by name and associated with a binder ID (`binder_id`), so the
     /// ordering is not important there.
     fn visit_early_late<F>(
         &mut self,
@@ -1705,25 +1703,22 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
             }
         }
 
-        let mut type_count = 0;
-        let lifetimes = generics
-            .params
-            .iter()
-            .filter_map(|param| match param.kind {
-                GenericParamKind::Lifetime { .. } => {
-                    if self.map.late_bound.contains(&param.id) {
-                        Some(Region::late(&self.tcx.hir(), param))
-                    } else {
-                        Some(Region::early(&self.tcx.hir(), &mut index, param))
-                    }
-                }
-                GenericParamKind::Type { .. } => {
-                    type_count += 1;
-                    None
+        let mut non_lifetime_count = 0;
+        let lifetimes = generics.params.iter().filter_map(|param| match param.kind {
+            GenericParamKind::Lifetime { .. } => {
+                if self.map.late_bound.contains(&param.id) {
+                    Some(Region::late(&self.tcx.hir(), param))
+                } else {
+                    Some(Region::early(&self.tcx.hir(), &mut index, param))
                 }
-            })
-            .collect();
-        let next_early_index = index + type_count;
+            }
+            GenericParamKind::Type { .. } |
+            GenericParamKind::Const { .. } => {
+                non_lifetime_count += 1;
+                None
+            }
+        }).collect();
+        let next_early_index = index + non_lifetime_count;
 
         let scope = Scope::Binder {
             lifetimes,
@@ -2013,6 +2008,9 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                     }
                     i += 1;
                 }
+                GenericArg::Const(ct) => {
+                    self.visit_anon_const(&ct.value);
+                }
             }
         }
 
@@ -2350,7 +2348,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                 } else {
                     (format!("{} + 'static", snippet), Applicability::MaybeIncorrect)
                 };
-                db.span_suggestion_with_applicability(span, msg, sugg, applicability);
+                db.span_suggestion(span, msg, sugg, applicability);
                 false
             }
             Err(_) => {
@@ -2593,12 +2591,12 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
                     ref lifetimes, s, ..
                 } => {
                     if let Some(&def) = lifetimes.get(&param.name.modern()) {
-                        let node_id = self.tcx.hir().as_local_node_id(def.id().unwrap()).unwrap();
+                        let hir_id = self.tcx.hir().as_local_hir_id(def.id().unwrap()).unwrap();
 
                         signal_shadowing_problem(
                             self.tcx,
                             param.name.ident().name,
-                            original_lifetime(self.tcx.hir().span(node_id)),
+                            original_lifetime(self.tcx.hir().span_by_hir_id(hir_id)),
                             shadower_lifetime(&param),
                         );
                         return;
@@ -2610,7 +2608,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         }
     }
 
-    /// Returns true if, in the current scope, replacing `'_` would be
+    /// Returns `true` if, in the current scope, replacing `'_` would be
     /// equivalent to a single-use lifetime.
     fn track_lifetime_uses(&self) -> bool {
         let mut scope = self.scope;
@@ -2714,7 +2712,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
 /// - it does not appear in a where-clause.
 ///
 /// "Constrained" basically means that it appears in any type but
-/// not amongst the inputs to a projection.  In other words, `<&'a
+/// not amongst the inputs to a projection. In other words, `<&'a
 /// T as Trait<''b>>::Foo` does not constrain `'a` or `'b`.
 fn insert_late_bound_lifetimes(
     map: &mut NamedRegionMap,
@@ -2770,8 +2768,9 @@ fn insert_late_bound_lifetimes(
         match param.kind {
             hir::GenericParamKind::Lifetime { .. } => { /* fall through */ }
 
-            // Types are not late-bound.
-            hir::GenericParamKind::Type { .. } => continue,
+            // Neither types nor consts are late-bound.
+            hir::GenericParamKind::Type { .. }
+            | hir::GenericParamKind::Const { .. } => continue,
         }
 
         let lt_name = hir::LifetimeName::Param(param.name.modern());
diff --git a/src/librustc/middle/stability.rs b/src/librustc/middle/stability.rs
index 918e286c435bc..30a43c7a92595 100644
--- a/src/librustc/middle/stability.rs
+++ b/src/librustc/middle/stability.rs
@@ -3,23 +3,23 @@
 
 pub use self::StabilityLevel::*;
 
-use lint::{self, Lint};
-use hir::{self, Item, Generics, StructField, Variant, HirId};
-use hir::def::Def;
-use hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
-use hir::intravisit::{self, Visitor, NestedVisitorMap};
-use ty::query::Providers;
-use ty::query::queries;
-use middle::privacy::AccessLevels;
-use session::{DiagnosticMessageId, Session};
+use crate::lint::{self, Lint};
+use crate::hir::{self, Item, Generics, StructField, Variant, HirId};
+use crate::hir::def::Def;
+use crate::hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
+use crate::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use crate::ty::query::Providers;
+use crate::middle::privacy::AccessLevels;
+use crate::session::{DiagnosticMessageId, Session};
 use syntax::symbol::Symbol;
 use syntax_pos::{Span, MultiSpan};
 use syntax::ast;
 use syntax::ast::{NodeId, Attribute};
+use syntax::errors::Applicability;
 use syntax::feature_gate::{GateIssue, emit_feature_err};
 use syntax::attr::{self, Stability, Deprecation};
-use ty::{self, TyCtxt};
-use util::nodemap::{FxHashSet, FxHashMap};
+use crate::ty::{self, TyCtxt};
+use crate::util::nodemap::{FxHashSet, FxHashMap};
 
 use std::mem::replace;
 use std::cmp::Ordering;
@@ -51,7 +51,7 @@ enum AnnotationKind {
 pub struct DeprecationEntry {
     /// The metadata of the attribute associated with this entry.
     pub attr: Deprecation,
-    /// The def id where the attr was originally attached. `None` for non-local
+    /// The `DefId` where the attr was originally attached. `None` for non-local
     /// `DefId`'s.
     origin: Option<HirId>,
 }
@@ -322,14 +322,17 @@ struct MissingStabilityAnnotations<'a, 'tcx: 'a> {
 }
 
 impl<'a, 'tcx: 'a> MissingStabilityAnnotations<'a, 'tcx> {
-    fn check_missing_stability(&self, id: NodeId, span: Span) {
+    fn check_missing_stability(&self, id: NodeId, span: Span, name: &str) {
         let hir_id = self.tcx.hir().node_to_hir_id(id);
         let stab = self.tcx.stability().local_stability(hir_id);
         let is_error = !self.tcx.sess.opts.test &&
                         stab.is_none() &&
                         self.access_levels.is_reachable(id);
         if is_error {
-            self.tcx.sess.span_err(span, "This node does not have a stability attribute");
+            self.tcx.sess.span_err(
+                span,
+                &format!("{} has missing stability attribute", name),
+            );
         }
     }
 }
@@ -347,42 +350,42 @@ impl<'a, 'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'a, 'tcx> {
             // optional. They inherit stability from their parents when unannotated.
             hir::ItemKind::Impl(.., None, _, _) | hir::ItemKind::ForeignMod(..) => {}
 
-            _ => self.check_missing_stability(i.id, i.span)
+            _ => self.check_missing_stability(i.id, i.span, i.node.descriptive_variant())
         }
 
         intravisit::walk_item(self, i)
     }
 
     fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem) {
-        self.check_missing_stability(ti.id, ti.span);
+        self.check_missing_stability(ti.id, ti.span, "item");
         intravisit::walk_trait_item(self, ti);
     }
 
     fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem) {
         let impl_def_id = self.tcx.hir().local_def_id(self.tcx.hir().get_parent(ii.id));
         if self.tcx.impl_trait_ref(impl_def_id).is_none() {
-            self.check_missing_stability(ii.id, ii.span);
+            self.check_missing_stability(ii.id, ii.span, "item");
         }
         intravisit::walk_impl_item(self, ii);
     }
 
     fn visit_variant(&mut self, var: &'tcx Variant, g: &'tcx Generics, item_id: NodeId) {
-        self.check_missing_stability(var.node.data.id(), var.span);
+        self.check_missing_stability(var.node.data.id(), var.span, "variant");
         intravisit::walk_variant(self, var, g, item_id);
     }
 
     fn visit_struct_field(&mut self, s: &'tcx StructField) {
-        self.check_missing_stability(s.id, s.span);
+        self.check_missing_stability(s.id, s.span, "field");
         intravisit::walk_struct_field(self, s);
     }
 
     fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem) {
-        self.check_missing_stability(i.id, i.span);
+        self.check_missing_stability(i.id, i.span, i.node.descriptive_variant());
         intravisit::walk_foreign_item(self, i);
     }
 
     fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef) {
-        self.check_missing_stability(md.id, md.span);
+        self.check_missing_stability(md.id, md.span, "macro");
     }
 }
 
@@ -458,7 +461,7 @@ impl<'a, 'tcx> Index<'tcx> {
 
 pub fn check_unstable_api_usage<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &module in tcx.hir().krate().modules.keys() {
-        queries::check_mod_unstable_api_usage::ensure(tcx, tcx.hir().local_def_id(module));
+        tcx.ensure().check_mod_unstable_api_usage(tcx.hir().local_def_id(module));
     }
 }
 
@@ -475,7 +478,7 @@ pub fn provide(providers: &mut Providers<'_>) {
     };
 }
 
-/// Check whether an item marked with `deprecated(since="X")` is currently
+/// Checks whether an item marked with `deprecated(since="X")` is currently
 /// deprecated (i.e., whether X is not greater than the current rustc version).
 pub fn deprecation_in_effect(since: &str) -> bool {
     fn parse_version(ver: &str) -> Vec<u32> {
@@ -561,14 +564,10 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     /// deprecated. If the item is indeed deprecated, we will emit a deprecation lint attached to
     /// `id`.
     pub fn eval_stability(self, def_id: DefId, id: Option<NodeId>, span: Span) -> EvalResult {
-        if span.allows_unstable() {
-            debug!("stability: skipping span={:?} since it is internal", span);
-            return EvalResult::Allow;
-        }
-
         let lint_deprecated = |def_id: DefId,
                                id: NodeId,
                                note: Option<Symbol>,
+                               suggestion: Option<Symbol>,
                                message: &str,
                                lint: &'static Lint| {
             let msg = if let Some(note) = note {
@@ -577,7 +576,18 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 format!("{}", message)
             };
 
-            self.lint_node(lint, id, span, &msg);
+            let mut diag = self.struct_span_lint_node(lint, id, span, &msg);
+            if let Some(suggestion) = suggestion {
+                if let hir::Node::Expr(_) = self.hir().get(id) {
+                    diag.span_suggestion(
+                        span,
+                        &msg,
+                        suggestion.to_string(),
+                        Applicability::MachineApplicable,
+                    );
+                }
+            }
+            diag.emit();
             if id == ast::DUMMY_NODE_ID {
                 span_bug!(span, "emitted a {} lint with dummy node id: {:?}", lint.name, def_id);
             }
@@ -586,41 +596,17 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // Deprecated attributes apply in-crate and cross-crate.
         if let Some(id) = id {
             if let Some(depr_entry) = self.lookup_deprecation_entry(def_id) {
-                // If the deprecation is scheduled for a future Rust
-                // version, then we should display no warning message.
-                let deprecated_in_future_version = if let Some(sym) = depr_entry.attr.since {
-                    let since = sym.as_str();
-                    if !deprecation_in_effect(&since) {
-                        Some(since)
-                    } else {
-                        None
-                    }
-                } else {
-                    None
-                };
-
                 let parent_def_id = self.hir().local_def_id(self.hir().get_parent(id));
                 let skip = self.lookup_deprecation_entry(parent_def_id)
                                .map_or(false, |parent_depr| parent_depr.same_origin(&depr_entry));
 
-                if let Some(since) = deprecated_in_future_version {
-                    let path = self.item_path_str(def_id);
-                    let message = format!("use of item '{}' \
-                                           that will be deprecated in future version {}",
-                                          path,
-                                          since);
-
-                    lint_deprecated(def_id,
-                                    id,
-                                    depr_entry.attr.note,
-                                    &message,
-                                    lint::builtin::DEPRECATED_IN_FUTURE);
-                } else if !skip {
+                if !skip {
                     let path = self.item_path_str(def_id);
                     let message = format!("use of deprecated item '{}'", path);
                     lint_deprecated(def_id,
                                     id,
                                     depr_entry.attr.note,
+                                    None,
                                     &message,
                                     lint::builtin::DEPRECATED);
                 }
@@ -639,27 +625,30 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         debug!("stability: \
                 inspecting def_id={:?} span={:?} of stability={:?}", def_id, span, stability);
 
-        if let Some(&Stability{rustc_depr: Some(attr::RustcDeprecation { reason, since }), ..})
-                = stability {
-            if let Some(id) = id {
-                let path = self.item_path_str(def_id);
-                if deprecation_in_effect(&since.as_str()) {
-                    let message = format!("use of deprecated item '{}'", path);
-                    lint_deprecated(def_id,
-                                    id,
-                                    Some(reason),
-                                    &message,
-                                    lint::builtin::DEPRECATED);
-                } else {
-                    let message = format!("use of item '{}' \
-                                           that will be deprecated in future version {}",
-                                          path,
-                                          since);
-                    lint_deprecated(def_id,
-                                    id,
-                                    Some(reason),
-                                    &message,
-                                    lint::builtin::DEPRECATED_IN_FUTURE);
+        if let Some(id) = id {
+            if let Some(stability) = stability {
+                if let Some(depr) = &stability.rustc_depr {
+                    let path = self.item_path_str(def_id);
+                    if deprecation_in_effect(&depr.since.as_str()) {
+                        let message = format!("use of deprecated item '{}'", path);
+                        lint_deprecated(def_id,
+                                        id,
+                                        Some(depr.reason),
+                                        depr.suggestion,
+                                        &message,
+                                        lint::builtin::DEPRECATED);
+                    } else {
+                        let message = format!("use of item '{}' \
+                                                that will be deprecated in future version {}",
+                                                path,
+                                                depr.since);
+                        lint_deprecated(def_id,
+                                        id,
+                                        Some(depr.reason),
+                                        depr.suggestion,
+                                        &message,
+                                        lint::builtin::DEPRECATED_IN_FUTURE);
+                    }
                 }
             }
         }
@@ -677,6 +666,10 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         match stability {
             Some(&Stability { level: attr::Unstable { reason, issue }, feature, .. }) => {
+                if span.allows_unstable(&feature.as_str()) {
+                    debug!("stability: skipping span={:?} since it is internal", span);
+                    return EvalResult::Allow;
+                }
                 if self.stability().active_features.contains(&feature) {
                     return EvalResult::Allow;
                 }
@@ -748,7 +741,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 }
             }
             EvalResult::Unmarked => {
-                span_bug!(span, "encountered unmarked API: {:?}", def_id);
+                // The API could be uncallable for other reasons, for example when a private module
+                // was referenced.
+                self.sess.delay_span_bug(span, &format!("encountered unmarked API: {:?}", def_id));
             }
         }
     }
@@ -848,7 +843,7 @@ pub fn check_unused_or_stable_features<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
             tcx,
             access_levels,
         };
-        missing.check_missing_stability(ast::CRATE_NODE_ID, krate.span);
+        missing.check_missing_stability(ast::CRATE_NODE_ID, krate.span, "crate");
         intravisit::walk_crate(&mut missing, krate);
         krate.visit_all_item_likes(&mut missing.as_deep_visitor());
     }
diff --git a/src/librustc/middle/weak_lang_items.rs b/src/librustc/middle/weak_lang_items.rs
index 82f19cbb82a19..312924e5e90f5 100644
--- a/src/librustc/middle/weak_lang_items.rs
+++ b/src/librustc/middle/weak_lang_items.rs
@@ -1,18 +1,18 @@
 //! Validity checking for weak lang items
 
-use session::config;
-use middle::lang_items;
+use crate::session::config;
+use crate::middle::lang_items;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_target::spec::PanicStrategy;
 use syntax::ast;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
-use hir::def_id::DefId;
-use hir::intravisit::{Visitor, NestedVisitorMap};
-use hir::intravisit;
-use hir;
-use ty::TyCtxt;
+use crate::hir::def_id::DefId;
+use crate::hir::intravisit::{Visitor, NestedVisitorMap};
+use crate::hir::intravisit;
+use crate::hir;
+use crate::ty::TyCtxt;
 
 macro_rules! weak_lang_items {
     ($($name:ident, $item:ident, $sym:ident;)*) => (
@@ -54,7 +54,7 @@ pub fn link_name(attrs: &[ast::Attribute]) -> Option<Symbol> {
     })
 }
 
-/// Returns whether the specified `lang_item` doesn't actually need to be
+/// Returns `true` if the specified `lang_item` doesn't actually need to be
 /// present for this compilation.
 ///
 /// Not all lang items are always required for each compilation, particularly in
diff --git a/src/librustc/mir/cache.rs b/src/librustc/mir/cache.rs
index 56ab263c47740..1cc927b1f720f 100644
--- a/src/librustc/mir/cache.rs
+++ b/src/librustc/mir/cache.rs
@@ -2,10 +2,10 @@ use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::sync::{RwLock, MappedReadGuard, ReadGuard};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
-use ich::StableHashingContext;
-use mir::{Mir, BasicBlock};
+use crate::ich::StableHashingContext;
+use crate::mir::{Mir, BasicBlock};
 
-use rustc_serialize as serialize;
+use crate::rustc_serialize as serialize;
 
 #[derive(Clone, Debug)]
 pub struct Cache {
diff --git a/src/librustc/mir/interpret/allocation.rs b/src/librustc/mir/interpret/allocation.rs
index 7ed29c5afd03f..e96392edd64bf 100644
--- a/src/librustc/mir/interpret/allocation.rs
+++ b/src/librustc/mir/interpret/allocation.rs
@@ -1,14 +1,14 @@
-//! The virtual memory representation of the MIR interpreter
+//! The virtual memory representation of the MIR interpreter.
 
 use super::{
     Pointer, EvalResult, AllocId, ScalarMaybeUndef, write_target_uint, read_target_uint, Scalar,
     truncate,
 };
 
-use ty::layout::{Size, Align};
+use crate::ty::layout::{Size, Align};
 use syntax::ast::Mutability;
 use std::iter;
-use mir;
+use crate::mir;
 use std::ops::{Deref, DerefMut};
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_target::abi::HasDataLayout;
@@ -54,7 +54,7 @@ pub trait AllocationExtra<Tag, MemoryExtra>: ::std::fmt::Debug + Clone {
     /// Hook for performing extra checks on a memory read access.
     ///
     /// Takes read-only access to the allocation so we can keep all the memory read
-    /// operations take `&self`.  Use a `RefCell` in `AllocExtra` if you
+    /// operations take `&self`. Use a `RefCell` in `AllocExtra` if you
     /// need to mutate.
     #[inline(always)]
     fn memory_read(
@@ -133,7 +133,7 @@ impl<'tcx> ::serialize::UseSpecializedDecodable for &'tcx Allocation {}
 
 /// Alignment and bounds checks
 impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
-    /// Check if the pointer is "in-bounds". Notice that a pointer pointing at the end
+    /// Checks if the pointer is "in-bounds". Notice that a pointer pointing at the end
     /// of an allocation (i.e., at the first *inaccessible* location) *is* considered
     /// in-bounds!  This follows C's/LLVM's rules.
     /// If you want to check bounds before doing a memory access, better use `check_bounds`.
@@ -145,7 +145,7 @@ impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
         ptr.check_in_alloc(Size::from_bytes(allocation_size), InboundsCheck::Live)
     }
 
-    /// Check if the memory range beginning at `ptr` and of size `Size` is "in-bounds".
+    /// Checks if the memory range beginning at `ptr` and of size `Size` is "in-bounds".
     #[inline(always)]
     pub fn check_bounds(
         &self,
@@ -161,7 +161,7 @@ impl<'tcx, Tag, Extra> Allocation<Tag, Extra> {
 /// Byte accessors
 impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
     /// The last argument controls whether we error out when there are undefined
-    /// or pointer bytes.  You should never call this, call `get_bytes` or
+    /// or pointer bytes. You should never call this, call `get_bytes` or
     /// `get_bytes_with_undef_and_ptr` instead,
     ///
     /// This function also guarantees that the resulting pointer will remain stable
@@ -462,7 +462,7 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
 
 /// Relocations
 impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
-    /// Return all relocations overlapping with the given ptr-offset pair.
+    /// Returns all relocations overlapping with the given ptr-offset pair.
     pub fn relocations(
         &self,
         cx: &impl HasDataLayout,
@@ -476,7 +476,7 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
         self.relocations.range(Size::from_bytes(start)..end)
     }
 
-    /// Check that there are no relocations overlapping with the given range.
+    /// Checks that there are no relocations overlapping with the given range.
     #[inline(always)]
     fn check_relocations(
         &self,
@@ -491,10 +491,10 @@ impl<'tcx, Tag: Copy, Extra> Allocation<Tag, Extra> {
         }
     }
 
-    /// Remove all relocations inside the given range.
+    /// Removes all relocations inside the given range.
     /// If there are relocations overlapping with the edges, they
     /// are removed as well *and* the bytes they cover are marked as
-    /// uninitialized.  This is a somewhat odd "spooky action at a distance",
+    /// uninitialized. This is a somewhat odd "spooky action at a distance",
     /// but it allows strictly more code to run than if we would just error
     /// immediately in that case.
     fn clear_relocations(
@@ -633,7 +633,7 @@ impl UndefMask {
         m
     }
 
-    /// Check whether the range `start..end` (end-exclusive) is entirely defined.
+    /// Checks whether the range `start..end` (end-exclusive) is entirely defined.
     ///
     /// Returns `Ok(())` if it's defined. Otherwise returns the index of the byte
     /// at which the first undefined access begins.
diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index c3fe5d773ab16..29beabdb2abdf 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -1,16 +1,16 @@
 use std::{fmt, env};
 
-use hir::map::definitions::DefPathData;
-use mir;
-use ty::{self, Ty, layout};
-use ty::layout::{Size, Align, LayoutError};
+use crate::hir::map::definitions::DefPathData;
+use crate::mir;
+use crate::ty::{self, Ty, layout};
+use crate::ty::layout::{Size, Align, LayoutError};
 use rustc_target::spec::abi::Abi;
 
 use super::{RawConst, Pointer, InboundsCheck, ScalarMaybeUndef};
 
 use backtrace::Backtrace;
 
-use ty::query::TyCtxtAt;
+use crate::ty::query::TyCtxtAt;
 use errors::DiagnosticBuilder;
 
 use syntax_pos::{Pos, Span};
@@ -19,7 +19,7 @@ use syntax::symbol::Symbol;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum ErrorHandled {
-    /// Already reported a lint or an error for this evaluation
+    /// Already reported a lint or an error for this evaluation.
     Reported,
     /// Don't emit an error, the evaluation failed because the MIR was generic
     /// and the substs didn't fully monomorphize it.
@@ -42,7 +42,7 @@ pub type ConstEvalResult<'tcx> = Result<ty::Const<'tcx>, ErrorHandled>;
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct ConstEvalErr<'tcx> {
     pub span: Span,
-    pub error: ::mir::interpret::EvalErrorKind<'tcx, u64>,
+    pub error: crate::mir::interpret::EvalErrorKind<'tcx, u64>,
     pub stacktrace: Vec<FrameInfo<'tcx>>,
 }
 
@@ -136,7 +136,7 @@ impl<'a, 'gcx, 'tcx> ConstEvalErr<'tcx> {
                 .next()
                 .unwrap_or(lint_root);
             tcx.struct_span_lint_node(
-                ::rustc::lint::builtin::CONST_ERR,
+                crate::rustc::lint::builtin::CONST_ERR,
                 node_id,
                 tcx.span,
                 message,
@@ -212,7 +212,7 @@ pub type AssertMessage<'tcx> = EvalErrorKind<'tcx, mir::Operand<'tcx>>;
 #[derive(Clone, RustcEncodable, RustcDecodable)]
 pub enum EvalErrorKind<'tcx, O> {
     /// This variant is used by machines to signal their own errors that do not
-    /// match an existing variant
+    /// match an existing variant.
     MachineError(String),
 
     FunctionAbiMismatch(Abi, Abi),
diff --git a/src/librustc/mir/interpret/mod.rs b/src/librustc/mir/interpret/mod.rs
index e6a560b2ad7b6..0c43fe4a79faa 100644
--- a/src/librustc/mir/interpret/mod.rs
+++ b/src/librustc/mir/interpret/mod.rs
@@ -25,17 +25,17 @@ pub use self::allocation::{
 pub use self::pointer::{Pointer, PointerArithmetic};
 
 use std::fmt;
-use mir;
-use hir::def_id::DefId;
-use ty::{self, TyCtxt, Instance};
-use ty::layout::{self, Size};
+use crate::mir;
+use crate::hir::def_id::DefId;
+use crate::ty::{self, TyCtxt, Instance, subst::UnpackedKind};
+use crate::ty::layout::{self, Size};
 use std::io;
-use rustc_serialize::{Encoder, Decodable, Encodable};
+use crate::rustc_serialize::{Encoder, Decodable, Encodable};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::{Lock as Mutex, HashMapExt};
 use rustc_data_structures::tiny_list::TinyList;
 use byteorder::{WriteBytesExt, ReadBytesExt, LittleEndian, BigEndian};
-use ty::codec::TyDecoder;
+use crate::ty::codec::TyDecoder;
 use std::sync::atomic::{AtomicU32, Ordering};
 use std::num::NonZeroU32;
 
@@ -53,8 +53,8 @@ pub struct GlobalId<'tcx> {
 #[derive(Copy, Clone, Eq, Hash, Ord, PartialEq, PartialOrd, Debug)]
 pub struct AllocId(pub u64);
 
-impl ::rustc_serialize::UseSpecializedEncodable for AllocId {}
-impl ::rustc_serialize::UseSpecializedDecodable for AllocId {}
+impl crate::rustc_serialize::UseSpecializedEncodable for AllocId {}
+impl crate::rustc_serialize::UseSpecializedDecodable for AllocId {}
 
 #[derive(RustcDecodable, RustcEncodable)]
 enum AllocDiscriminant {
@@ -260,23 +260,23 @@ impl fmt::Display for AllocId {
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash, RustcDecodable, RustcEncodable)]
 pub enum AllocKind<'tcx> {
-    /// The alloc id is used as a function pointer
+    /// The alloc ID is used as a function pointer
     Function(Instance<'tcx>),
-    /// The alloc id points to a "lazy" static variable that did not get computed (yet).
+    /// The alloc ID points to a "lazy" static variable that did not get computed (yet).
     /// This is also used to break the cycle in recursive statics.
     Static(DefId),
-    /// The alloc id points to memory
+    /// The alloc ID points to memory.
     Memory(&'tcx Allocation),
 }
 
 pub struct AllocMap<'tcx> {
-    /// Lets you know what an AllocId refers to
+    /// Lets you know what an `AllocId` refers to.
     id_to_kind: FxHashMap<AllocId, AllocKind<'tcx>>,
 
-    /// Used to ensure that statics only get one associated AllocId
+    /// Used to ensure that statics only get one associated `AllocId`.
     type_interner: FxHashMap<AllocKind<'tcx>, AllocId>,
 
-    /// The AllocId to assign to the next requested id.
+    /// The `AllocId` to assign to the next requested ID.
     /// Always incremented, never gets smaller.
     next_id: AllocId,
 }
@@ -318,14 +318,29 @@ impl<'tcx> AllocMap<'tcx> {
         id
     }
 
-    /// Functions cannot be identified by pointers, as asm-equal functions can get deduplicated
-    /// by the linker and functions can be duplicated across crates.
-    /// We thus generate a new `AllocId` for every mention of a function. This means that
-    /// `main as fn() == main as fn()` is false, while `let x = main as fn(); x == x` is true.
     pub fn create_fn_alloc(&mut self, instance: Instance<'tcx>) -> AllocId {
-        let id = self.reserve();
-        self.id_to_kind.insert(id, AllocKind::Function(instance));
-        id
+        // Functions cannot be identified by pointers, as asm-equal functions can get deduplicated
+        // by the linker (we set the "unnamed_addr" attribute for LLVM) and functions can be
+        // duplicated across crates.
+        // We thus generate a new `AllocId` for every mention of a function. This means that
+        // `main as fn() == main as fn()` is false, while `let x = main as fn(); x == x` is true.
+        // However, formatting code relies on function identity (see #58320), so we only do
+        // this for generic functions.  Lifetime parameters are ignored.
+        let is_generic = instance.substs.into_iter().any(|kind| {
+            match kind.unpack() {
+                UnpackedKind::Lifetime(_) => false,
+                _ => true,
+            }
+        });
+        if is_generic {
+            // Get a fresh ID
+            let id = self.reserve();
+            self.id_to_kind.insert(id, AllocKind::Function(instance));
+            id
+        } else {
+            // Deduplicate
+            self.intern(AllocKind::Function(instance))
+        }
     }
 
     /// Returns `None` in case the `AllocId` is dangling. An `EvalContext` can still have a
@@ -345,7 +360,7 @@ impl<'tcx> AllocMap<'tcx> {
         }
     }
 
-    /// Generate an `AllocId` for a static or return a cached one in case this function has been
+    /// Generates an `AllocId` for a static or return a cached one in case this function has been
     /// called on the same static before.
     pub fn intern_static(&mut self, static_id: DefId) -> AllocId {
         self.intern(AllocKind::Static(static_id))
diff --git a/src/librustc/mir/interpret/pointer.rs b/src/librustc/mir/interpret/pointer.rs
index a046825f088bb..551e7b2fd41ec 100644
--- a/src/librustc/mir/interpret/pointer.rs
+++ b/src/librustc/mir/interpret/pointer.rs
@@ -1,5 +1,5 @@
-use mir;
-use ty::layout::{self, HasDataLayout, Size};
+use crate::mir;
+use crate::ty::layout::{self, HasDataLayout, Size};
 
 use super::{
     AllocId, EvalResult, InboundsCheck,
@@ -76,6 +76,8 @@ pub struct Pointer<Tag=(),Id=AllocId> {
     pub tag: Tag,
 }
 
+static_assert!(POINTER_SIZE: ::std::mem::size_of::<Pointer>() == 16);
+
 /// Produces a `Pointer` which points to the beginning of the Allocation
 impl From<AllocId> for Pointer {
     #[inline(always)]
diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs
index 76eb43e73d166..5ec7de4308a13 100644
--- a/src/librustc/mir/interpret/value.rs
+++ b/src/librustc/mir/interpret/value.rs
@@ -13,31 +13,38 @@ pub struct RawConst<'tcx> {
     pub ty: Ty<'tcx>,
 }
 
-/// Represents a constant value in Rust. Scalar and ScalarPair are optimizations which
-/// matches the LocalValue optimizations for easy conversions between Value and ConstValue.
+/// Represents a constant value in Rust. `Scalar` and `ScalarPair` are optimizations that
+/// match the `LocalState` optimizations for easy conversions between `Value` and `ConstValue`.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, RustcEncodable, RustcDecodable, Hash)]
 pub enum ConstValue<'tcx> {
-    /// Used only for types with layout::abi::Scalar ABI and ZSTs
+    /// Used only for types with `layout::abi::Scalar` ABI and ZSTs.
     ///
-    /// Not using the enum `Value` to encode that this must not be `Undef`
+    /// Not using the enum `Value` to encode that this must not be `Undef`.
     Scalar(Scalar),
 
-    /// Used only for *fat pointers* with layout::abi::ScalarPair
+    /// Used only for slices and strings (`&[T]`, `&str`, `*const [T]`, `*mut str`, `Box<str>`,
+    /// etc.).
     ///
-    /// Needed for pattern matching code related to slices and strings.
-    ScalarPair(Scalar, Scalar),
-
-    /// An allocation + offset into the allocation.
-    /// Invariant: The AllocId matches the allocation.
+    /// Empty slices don't necessarily have an address backed by an `AllocId`, thus we also need to
+    /// enable integer pointers. The `Scalar` type covers exactly those two cases. While we could
+    /// create dummy-`AllocId`s, the additional code effort for the conversions doesn't seem worth
+    /// it.
+    Slice(Scalar, u64),
+
+    /// An allocation together with an offset into the allocation.
+    /// Invariant: the `AllocId` matches the allocation.
     ByRef(AllocId, &'tcx Allocation, Size),
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(CONST_SIZE: ::std::mem::size_of::<ConstValue<'static>>() == 40);
+
 impl<'tcx> ConstValue<'tcx> {
     #[inline]
     pub fn try_to_scalar(&self) -> Option<Scalar> {
         match *self {
             ConstValue::ByRef(..) |
-            ConstValue::ScalarPair(..) => None,
+            ConstValue::Slice(..) => None,
             ConstValue::Scalar(val) => Some(val),
         }
     }
@@ -56,17 +63,8 @@ impl<'tcx> ConstValue<'tcx> {
     pub fn new_slice(
         val: Scalar,
         len: u64,
-        cx: &impl HasDataLayout
     ) -> Self {
-        ConstValue::ScalarPair(val, Scalar::Bits {
-            bits: len as u128,
-            size: cx.data_layout().pointer_size.bytes() as u8,
-        })
-    }
-
-    #[inline]
-    pub fn new_dyn_trait(val: Scalar, vtable: Pointer) -> Self {
-        ConstValue::ScalarPair(val, Scalar::Ptr(vtable))
+        ConstValue::Slice(val, len)
     }
 }
 
@@ -90,6 +88,9 @@ pub enum Scalar<Tag=(), Id=AllocId> {
     Ptr(Pointer<Tag, Id>),
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(SCALAR_SIZE: ::std::mem::size_of::<Scalar>() == 24);
+
 impl<Tag> fmt::Display for Scalar<Tag> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
@@ -515,7 +516,7 @@ impl<'tcx, Tag> ScalarMaybeUndef<Tag> {
     }
 }
 
-impl_stable_hash_for!(enum ::mir::interpret::ScalarMaybeUndef {
+impl_stable_hash_for!(enum crate::mir::interpret::ScalarMaybeUndef {
     Scalar(v),
     Undef
 });
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index a1a6e890b1292..3513d652b5346 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -2,11 +2,11 @@
 //!
 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
 
-use hir::def::CtorKind;
-use hir::def_id::DefId;
-use hir::{self, HirId, InlineAsm};
-use mir::interpret::{ConstValue, EvalErrorKind, Scalar};
-use mir::visit::MirVisitable;
+use crate::hir::def::CtorKind;
+use crate::hir::def_id::DefId;
+use crate::hir::{self, HirId, InlineAsm};
+use crate::mir::interpret::{ConstValue, EvalErrorKind, Scalar};
+use crate::mir::visit::MirVisitable;
 use rustc_apfloat::ieee::{Double, Single};
 use rustc_apfloat::Float;
 use rustc_data_structures::fx::FxHashSet;
@@ -15,7 +15,7 @@ use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::sync::MappedReadGuard;
-use rustc_serialize::{self as serialize};
+use crate::rustc_serialize::{self as serialize};
 use smallvec::SmallVec;
 use std::borrow::Cow;
 use std::fmt::{self, Debug, Formatter, Write};
@@ -26,16 +26,16 @@ use std::{iter, mem, option, u32};
 use syntax::ast::{self, Name};
 use syntax::symbol::InternedString;
 use syntax_pos::{Span, DUMMY_SP};
-use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
-use ty::subst::{Subst, Substs};
-use ty::layout::VariantIdx;
-use ty::{
+use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::layout::VariantIdx;
+use crate::ty::{
     self, AdtDef, CanonicalUserTypeAnnotations, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
-    UserTypeAnnotationIndex, UserTypeAnnotation,
+    UserTypeAnnotationIndex,
 };
-use util::ppaux;
+use crate::util::ppaux;
 
-pub use mir::interpret::AssertMessage;
+pub use crate::mir::interpret::AssertMessage;
 
 mod cache;
 pub mod interpret;
@@ -108,7 +108,7 @@ pub struct Mir<'tcx> {
     /// in scope, but a separate set of locals.
     pub promoted: IndexVec<Promoted, Mir<'tcx>>,
 
-    /// Yield type of the function, if it is a generator.
+    /// Yields type of the function, if it is a generator.
     pub yield_ty: Option<Ty<'tcx>>,
 
     /// Generator drop glue
@@ -380,7 +380,7 @@ impl<'tcx> Mir<'tcx> {
         }
     }
 
-    /// Check if `sub` is a sub scope of `sup`
+    /// Checks if `sub` is a sub scope of `sup`
     pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
         while sub != sup {
             match self.source_scopes[sub].parent_scope {
@@ -391,12 +391,12 @@ impl<'tcx> Mir<'tcx> {
         true
     }
 
-    /// Return the return type, it always return first element from `local_decls` array
+    /// Returns the return type, it always return first element from `local_decls` array
     pub fn return_ty(&self) -> Ty<'tcx> {
         self.local_decls[RETURN_PLACE].ty
     }
 
-    /// Get the location of the terminator for the given block
+    /// Gets the location of the terminator for the given block
     pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
         Location {
             block: bb,
@@ -526,7 +526,7 @@ pub enum BorrowKind {
     /// We can also report errors with this kind of borrow differently.
     Shallow,
 
-    /// Data must be immutable but not aliasable.  This kind of borrow
+    /// Data must be immutable but not aliasable. This kind of borrow
     /// cannot currently be expressed by the user and is used only in
     /// implicit closure bindings. It is needed when the closure is
     /// borrowing or mutating a mutable referent, e.g.:
@@ -565,8 +565,8 @@ pub enum BorrowKind {
 
     /// Data is mutable and not aliasable.
     Mut {
-        /// True if this borrow arose from method-call auto-ref
-        /// (i.e., `adjustment::Adjust::Borrow`)
+        /// `true` if this borrow arose from method-call auto-ref
+        /// (i.e., `adjustment::Adjust::Borrow`).
         allow_two_phase_borrow: bool,
     },
 }
@@ -610,7 +610,7 @@ pub struct VarBindingForm<'tcx> {
     /// If an explicit type was provided for this variable binding,
     /// this holds the source Span of that type.
     ///
-    /// NOTE: If you want to change this to a `HirId`, be wary that
+    /// NOTE: if you want to change this to a `HirId`, be wary that
     /// doing so breaks incremental compilation (as of this writing),
     /// while a `Span` does not cause our tests to fail.
     pub opt_ty_info: Option<Span>,
@@ -676,7 +676,7 @@ impl_stable_hash_for!(enum self::MirPhase {
 });
 
 mod binding_form_impl {
-    use ich::StableHashingContext;
+    use crate::ich::StableHashingContext;
     use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
 
     impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
@@ -737,7 +737,7 @@ pub struct LocalDecl<'tcx> {
     /// `ClearCrossCrate` as long as it carries as `HirId`.
     pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
 
-    /// True if this is an internal local
+    /// `true` if this is an internal local.
     ///
     /// These locals are not based on types in the source code and are only used
     /// for a few desugarings at the moment.
@@ -864,7 +864,7 @@ pub struct LocalDecl<'tcx> {
 }
 
 impl<'tcx> LocalDecl<'tcx> {
-    /// Returns true only if local is a binding that can itself be
+    /// Returns `true` only if local is a binding that can itself be
     /// made mutable via the addition of the `mut` keyword, namely
     /// something like the occurrences of `x` in:
     /// - `fn foo(x: Type) { ... }`,
@@ -886,7 +886,7 @@ impl<'tcx> LocalDecl<'tcx> {
         }
     }
 
-    /// Returns true if local is definitely not a `ref ident` or
+    /// Returns `true` if local is definitely not a `ref ident` or
     /// `ref mut ident` binding. (Such bindings cannot be made into
     /// mutable bindings, but the inverse does not necessarily hold).
     pub fn is_nonref_binding(&self) -> bool {
@@ -904,7 +904,7 @@ impl<'tcx> LocalDecl<'tcx> {
         }
     }
 
-    /// Create a new `LocalDecl` for a temporary.
+    /// Creates a new `LocalDecl` for a temporary.
     #[inline]
     pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
         Self::new_local(ty, Mutability::Mut, false, span)
@@ -925,7 +925,7 @@ impl<'tcx> LocalDecl<'tcx> {
         self
     }
 
-    /// Create a new `LocalDecl` for a internal temporary.
+    /// Creates a new `LocalDecl` for a internal temporary.
     #[inline]
     pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
         Self::new_local(ty, Mutability::Mut, true, span)
@@ -1019,7 +1019,7 @@ pub struct BasicBlockData<'tcx> {
 
     /// Terminator for this block.
     ///
-    /// NB. This should generally ONLY be `None` during construction.
+    /// N.B., this should generally ONLY be `None` during construction.
     /// Therefore, you should generally access it via the
     /// `terminator()` or `terminator_mut()` methods. The only
     /// exception is that certain passes, such as `simplify_cfg`, swap
@@ -1637,7 +1637,7 @@ impl<'tcx> TerminatorKind<'tcx> {
         }
     }
 
-    /// Return the list of labels for the edges to the successor basic blocks.
+    /// Returns the list of labels for the edges to the successor basic blocks.
     pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
         use self::TerminatorKind::*;
         match *self {
@@ -1760,7 +1760,7 @@ pub enum StatementKind<'tcx> {
     /// error messages to these specific patterns.
     ///
     /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
-    /// never accessed still get some sanity checks for e.g. `let x: ! = ..;`
+    /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
     FakeRead(FakeReadCause, Place<'tcx>),
 
     /// Write the discriminant for a variant to the enum Place.
@@ -1775,14 +1775,14 @@ pub enum StatementKind<'tcx> {
     /// End the current live range for the storage of the local.
     StorageDead(Local),
 
-    /// Execute a piece of inline Assembly.
+    /// Executes a piece of inline Assembly.
     InlineAsm {
         asm: Box<InlineAsm>,
         outputs: Box<[Place<'tcx>]>,
         inputs: Box<[(Span, Operand<'tcx>)]>,
     },
 
-    /// Retag references in the given place, ensuring they got fresh tags.  This is
+    /// Retag references in the given place, ensuring they got fresh tags. This is
     /// part of the Stacked Borrows model. These statements are currently only interpreted
     /// by miri and only generated when "-Z mir-emit-retag" is passed.
     /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
@@ -1904,7 +1904,7 @@ pub enum Place<'tcx> {
     Projection(Box<PlaceProjection<'tcx>>),
 }
 
-/// The def-id of a static, along with its normalized type (which is
+/// The `DefId` of a static, along with its normalized type (which is
 /// stored to avoid requiring normalization when reading MIR).
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
 pub struct Static<'tcx> {
@@ -2009,10 +2009,10 @@ impl<'tcx> Place<'tcx> {
         Place::Projection(Box::new(PlaceProjection { base: self, elem }))
     }
 
-    /// Find the innermost `Local` from this `Place`, *if* it is either a local itself or
+    /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
     /// a single deref of a local.
-    ///
-    /// FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
+    //
+    // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
     pub fn local(&self) -> Option<Local> {
         match self {
             Place::Local(local) |
@@ -2024,7 +2024,7 @@ impl<'tcx> Place<'tcx> {
         }
     }
 
-    /// Find the innermost `Local` from this `Place`.
+    /// Finds the innermost `Local` from this `Place`.
     pub fn base_local(&self) -> Option<Local> {
         match self {
             Place::Local(local) => Some(*local),
@@ -2141,7 +2141,7 @@ impl<'tcx> Debug for Operand<'tcx> {
 
 impl<'tcx> Operand<'tcx> {
     /// Convenience helper to make a constant that refers to the fn
-    /// with given def-id and substs. Since this is used to synthesize
+    /// with given `DefId` and substs. Since this is used to synthesize
     /// MIR, assumes `user_ty` is None.
     pub fn function_handle<'a>(
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -2154,7 +2154,7 @@ impl<'tcx> Operand<'tcx> {
             span,
             ty,
             user_ty: None,
-            literal: tcx.intern_lazy_const(
+            literal: tcx.mk_lazy_const(
                 ty::LazyConst::Evaluated(ty::Const::zero_sized(ty)),
             ),
         })
@@ -2199,7 +2199,7 @@ pub enum Rvalue<'tcx> {
     /// be defined to return, say, a 0) if ADT is not an enum.
     Discriminant(Place<'tcx>),
 
-    /// Create an aggregate value, like a tuple or struct.  This is
+    /// Creates an aggregate value, like a tuple or struct. This is
     /// only needed because we want to distinguish `dest = Foo { x:
     /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
     /// that `Foo` has a destructor. These rvalues can be optimized
@@ -2211,13 +2211,13 @@ pub enum Rvalue<'tcx> {
 pub enum CastKind {
     Misc,
 
-    /// Convert unique, zero-sized type for a fn to fn()
+    /// Converts unique, zero-sized type for a fn to fn()
     ReifyFnPointer,
 
-    /// Convert non capturing closure to fn()
+    /// Converts non capturing closure to fn()
     ClosureFnPointer,
 
-    /// Convert safe fn() to unsafe fn()
+    /// Converts safe fn() to unsafe fn()
     UnsafeFnPointer,
 
     /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
@@ -2301,9 +2301,9 @@ impl BinOp {
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum NullOp {
-    /// Return the size of a value of that type
+    /// Returns the size of a value of that type
     SizeOf,
-    /// Create a new uninitialized box for a value of that type
+    /// Creates a new uninitialized box for a value of that type
     Box,
 }
 
@@ -2625,7 +2625,7 @@ CloneTypeFoldableAndLiftImpls! { ProjectionKind<'tcx>, }
 
 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        use mir::ProjectionElem::*;
+        use crate::mir::ProjectionElem::*;
 
         let base = self.base.fold_with(folder);
         let projs: Vec<_> = self.projs
@@ -2671,7 +2671,7 @@ pub fn fmt_lazy_const_val(f: &mut impl Write, const_val: &ty::LazyConst<'_>) ->
 
 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
 pub fn fmt_const_val(f: &mut impl Write, const_val: ty::Const<'_>) -> fmt::Result {
-    use ty::TyKind::*;
+    use crate::ty::TyKind::*;
     let value = const_val.val;
     let ty = const_val.ty;
     // print some primitives
@@ -2702,23 +2702,21 @@ pub fn fmt_const_val(f: &mut impl Write, const_val: ty::Const<'_>) -> fmt::Resul
         return write!(f, "{}", item_path_str(did));
     }
     // print string literals
-    if let ConstValue::ScalarPair(ptr, len) = value {
+    if let ConstValue::Slice(ptr, len) = value {
         if let Scalar::Ptr(ptr) = ptr {
-            if let Scalar::Bits { bits: len, .. } = len {
-                if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty {
-                    return ty::tls::with(|tcx| {
-                        let alloc = tcx.alloc_map.lock().get(ptr.alloc_id);
-                        if let Some(interpret::AllocKind::Memory(alloc)) = alloc {
-                            assert_eq!(len as usize as u128, len);
-                            let slice =
-                                &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
-                            let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
-                            write!(f, "{:?}", s)
-                        } else {
-                            write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len)
-                        }
-                    });
-                }
+            if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty {
+                return ty::tls::with(|tcx| {
+                    let alloc = tcx.alloc_map.lock().get(ptr.alloc_id);
+                    if let Some(interpret::AllocKind::Memory(alloc)) = alloc {
+                        assert_eq!(len as usize as u64, len);
+                        let slice =
+                            &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
+                        let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
+                        write!(f, "{:?}", s)
+                    } else {
+                        write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len)
+                    }
+                });
             }
         }
     }
@@ -2849,7 +2847,7 @@ impl Location {
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub enum UnsafetyViolationKind {
     General,
-    /// Permitted in const fn and regular fns
+    /// Permitted in const fn and regular fns.
     GeneralAndConstFn,
     ExternStatic(ast::NodeId),
     BorrowPacked(ast::NodeId),
@@ -2886,7 +2884,7 @@ pub struct BorrowCheckResult<'gcx> {
 
 /// After we borrow check a closure, we are left with various
 /// requirements that we have inferred between the free regions that
-/// appear in the closure's signature or on its field types.  These
+/// appear in the closure's signature or on its field types. These
 /// requirements are then verified and proved by the closure's
 /// creating function. This struct encodes those requirements.
 ///
@@ -2936,7 +2934,7 @@ pub struct BorrowCheckResult<'gcx> {
 /// internally within the rest of the NLL code).
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct ClosureRegionRequirements<'gcx> {
-    /// The number of external regions defined on the closure.  In our
+    /// The number of external regions defined on the closure. In our
     /// example above, it would be 3 -- one for `'static`, then `'1`
     /// and `'2`. This is just used for a sanity check later on, to
     /// make sure that the number of regions we see at the callsite
@@ -3118,7 +3116,7 @@ EnumTypeFoldableImpl! {
 
 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        use mir::TerminatorKind::*;
+        use crate::mir::TerminatorKind::*;
 
         let kind = match self.kind {
             Goto { target } => Goto { target },
@@ -3231,7 +3229,7 @@ impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        use mir::TerminatorKind::*;
+        use crate::mir::TerminatorKind::*;
 
         match self.kind {
             SwitchInt {
@@ -3303,7 +3301,7 @@ impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
 
 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        use mir::Rvalue::*;
+        use crate::mir::Rvalue::*;
         match *self {
             Use(ref op) => Use(op.fold_with(folder)),
             Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
@@ -3345,7 +3343,7 @@ impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        use mir::Rvalue::*;
+        use crate::mir::Rvalue::*;
         match *self {
             Use(ref op) => op.visit_with(visitor),
             Repeat(ref op, _) => op.visit_with(visitor),
@@ -3397,7 +3395,7 @@ where
     T: TypeFoldable<'tcx>,
 {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        use mir::ProjectionElem::*;
+        use crate::mir::ProjectionElem::*;
 
         let base = self.base.fold_with(folder);
         let elem = match self.elem {
@@ -3411,7 +3409,7 @@ where
     }
 
     fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
-        use mir::ProjectionElem::*;
+        use crate::mir::ProjectionElem::*;
 
         self.base.visit_with(visitor) || match self.elem {
             Field(_, ref ty) => ty.visit_with(visitor),
diff --git a/src/librustc/mir/mono.rs b/src/librustc/mir/mono.rs
index 55f5c36cde66d..2296fe5763c94 100644
--- a/src/librustc/mir/mono.rs
+++ b/src/librustc/mir/mono.rs
@@ -1,12 +1,12 @@
-use hir::def_id::{DefId, CrateNum, LOCAL_CRATE};
+use crate::hir::def_id::{DefId, CrateNum, LOCAL_CRATE};
 use syntax::ast::NodeId;
 use syntax::symbol::{Symbol, InternedString};
-use ty::{Instance, TyCtxt};
-use util::nodemap::FxHashMap;
+use crate::ty::{Instance, TyCtxt};
+use crate::util::nodemap::FxHashMap;
 use rustc_data_structures::base_n;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasherResult,
                                            StableHasher};
-use ich::{Fingerprint, StableHashingContext, NodeIdHashingMode};
+use crate::ich::{Fingerprint, StableHashingContext, NodeIdHashingMode};
 use std::fmt;
 use std::hash::Hash;
 
@@ -57,7 +57,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for MonoItem<'tcx> {
 
 pub struct CodegenUnit<'tcx> {
     /// A name for this CGU. Incremental compilation requires that
-    /// name be unique amongst **all** crates.  Therefore, it should
+    /// name be unique amongst **all** crates. Therefore, it should
     /// contain something unique to this crate (e.g., a module path)
     /// as well as the crate name and disambiguator.
     name: InternedString,
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
index c5b884525da4b..bf4ac7496d2e7 100644
--- a/src/librustc/mir/tcx.rs
+++ b/src/librustc/mir/tcx.rs
@@ -3,12 +3,12 @@
  * building is complete.
  */
 
-use mir::*;
-use ty::subst::{Subst, Substs};
-use ty::{self, AdtDef, Ty, TyCtxt};
-use ty::layout::VariantIdx;
-use hir;
-use ty::util::IntTypeExt;
+use crate::mir::*;
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::{self, AdtDef, Ty, TyCtxt};
+use crate::ty::layout::VariantIdx;
+use crate::hir;
+use crate::ty::util::IntTypeExt;
 
 #[derive(Copy, Clone, Debug)]
 pub enum PlaceTy<'tcx> {
@@ -75,8 +75,7 @@ impl<'a, 'gcx, 'tcx> PlaceTy<'tcx> {
                          elem: &PlaceElem<'tcx>)
                          -> PlaceTy<'tcx>
     {
-        self.projection_ty_core(tcx, elem, |_, _, ty| -> Result<Ty<'tcx>, ()> { Ok(ty) })
-            .unwrap()
+        self.projection_ty_core(tcx, elem, |_, _, ty| ty)
     }
 
     /// `place_ty.projection_ty_core(tcx, elem, |...| { ... })`
@@ -84,12 +83,12 @@ impl<'a, 'gcx, 'tcx> PlaceTy<'tcx> {
     /// `Ty` or downcast variant corresponding to that projection.
     /// The `handle_field` callback must map a `Field` to its `Ty`,
     /// (which should be trivial when `T` = `Ty`).
-    pub fn projection_ty_core<V, T, E>(
+    pub fn projection_ty_core<V, T>(
         self,
         tcx: TyCtxt<'a, 'gcx, 'tcx>,
         elem: &ProjectionElem<'tcx, V, T>,
-        mut handle_field: impl FnMut(&Self, &Field, &T) -> Result<Ty<'tcx>, E>)
-        -> Result<PlaceTy<'tcx>, E>
+        mut handle_field: impl FnMut(&Self, &Field, &T) -> Ty<'tcx>)
+        -> PlaceTy<'tcx>
     where
         V: ::std::fmt::Debug, T: ::std::fmt::Debug
     {
@@ -140,10 +139,10 @@ impl<'a, 'gcx, 'tcx> PlaceTy<'tcx> {
                     }
                 },
             ProjectionElem::Field(ref f, ref fty) =>
-                PlaceTy::Ty { ty: handle_field(&self, f, fty)? },
+                PlaceTy::Ty { ty: handle_field(&self, f, fty) },
         };
         debug!("projection_ty self: {:?} elem: {:?} yields: {:?}", self, elem, answer);
-        Ok(answer)
+        answer
     }
 }
 
@@ -279,7 +278,7 @@ impl<'tcx> Rvalue<'tcx> {
     }
 
     #[inline]
-    /// Returns whether this rvalue is deeply initialized (most rvalues) or
+    /// Returns `true` if this rvalue is deeply initialized (most rvalues) or
     /// whether its only shallowly initialized (`Rvalue::Box`).
     pub fn initialization_state(&self) -> RvalueInitializationState {
         match *self {
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index a0fae3aa927ce..e5828039ac29c 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -1,8 +1,7 @@
-use hir::def_id::DefId;
-use infer::canonical::Canonical;
-use ty::subst::Substs;
-use ty::{ClosureSubsts, GeneratorSubsts, Region, Ty};
-use mir::*;
+use crate::hir::def_id::DefId;
+use crate::ty::subst::Substs;
+use crate::ty::{CanonicalUserTypeAnnotation, ClosureSubsts, GeneratorSubsts, Region, Ty};
+use crate::mir::*;
 use syntax_pos::Span;
 
 // # The MIR Visitor
@@ -39,10 +38,10 @@ use syntax_pos::Span;
 // ```rust
 // fn super_basic_block_data(&mut self,
 //                           block: BasicBlock,
-//                           data: & $($mutability)* BasicBlockData<'tcx>) {
+//                           data: & $($mutability)? BasicBlockData<'tcx>) {
 //     let BasicBlockData {
-//         ref $($mutability)* statements,
-//         ref $($mutability)* terminator,
+//         statements,
+//         terminator,
 //         is_cleanup: _
 //     } = *data;
 //
@@ -68,111 +67,111 @@ use syntax_pos::Span;
 // `is_cleanup` above.
 
 macro_rules! make_mir_visitor {
-    ($visitor_trait_name:ident, $($mutability:ident)*) => {
+    ($visitor_trait_name:ident, $($mutability:ident)?) => {
         pub trait $visitor_trait_name<'tcx> {
             // Override these, and call `self.super_xxx` to revert back to the
             // default behavior.
 
-            fn visit_mir(&mut self, mir: & $($mutability)* Mir<'tcx>) {
+            fn visit_mir(&mut self, mir: & $($mutability)? Mir<'tcx>) {
                 self.super_mir(mir);
             }
 
             fn visit_basic_block_data(&mut self,
                                       block: BasicBlock,
-                                      data: & $($mutability)* BasicBlockData<'tcx>) {
+                                      data: & $($mutability)? BasicBlockData<'tcx>) {
                 self.super_basic_block_data(block, data);
             }
 
             fn visit_source_scope_data(&mut self,
-                                           scope_data: & $($mutability)* SourceScopeData) {
+                                           scope_data: & $($mutability)? SourceScopeData) {
                 self.super_source_scope_data(scope_data);
             }
 
             fn visit_statement(&mut self,
                                block: BasicBlock,
-                               statement: & $($mutability)* Statement<'tcx>,
+                               statement: & $($mutability)? Statement<'tcx>,
                                location: Location) {
                 self.super_statement(block, statement, location);
             }
 
             fn visit_assign(&mut self,
                             block: BasicBlock,
-                            place: & $($mutability)* Place<'tcx>,
-                            rvalue: & $($mutability)* Rvalue<'tcx>,
+                            place: & $($mutability)? Place<'tcx>,
+                            rvalue: & $($mutability)? Rvalue<'tcx>,
                             location: Location) {
                 self.super_assign(block, place, rvalue, location);
             }
 
             fn visit_terminator(&mut self,
                                 block: BasicBlock,
-                                terminator: & $($mutability)* Terminator<'tcx>,
+                                terminator: & $($mutability)? Terminator<'tcx>,
                                 location: Location) {
                 self.super_terminator(block, terminator, location);
             }
 
             fn visit_terminator_kind(&mut self,
                                      block: BasicBlock,
-                                     kind: & $($mutability)* TerminatorKind<'tcx>,
+                                     kind: & $($mutability)? TerminatorKind<'tcx>,
                                      location: Location) {
                 self.super_terminator_kind(block, kind, location);
             }
 
             fn visit_assert_message(&mut self,
-                                    msg: & $($mutability)* AssertMessage<'tcx>,
+                                    msg: & $($mutability)? AssertMessage<'tcx>,
                                     location: Location) {
                 self.super_assert_message(msg, location);
             }
 
             fn visit_rvalue(&mut self,
-                            rvalue: & $($mutability)* Rvalue<'tcx>,
+                            rvalue: & $($mutability)? Rvalue<'tcx>,
                             location: Location) {
                 self.super_rvalue(rvalue, location);
             }
 
             fn visit_operand(&mut self,
-                             operand: & $($mutability)* Operand<'tcx>,
+                             operand: & $($mutability)? Operand<'tcx>,
                              location: Location) {
                 self.super_operand(operand, location);
             }
 
             fn visit_ascribe_user_ty(&mut self,
-                                     place: & $($mutability)* Place<'tcx>,
-                                     variance: & $($mutability)* ty::Variance,
-                                     user_ty: & $($mutability)* UserTypeProjection<'tcx>,
+                                     place: & $($mutability)? Place<'tcx>,
+                                     variance: & $($mutability)? ty::Variance,
+                                     user_ty: & $($mutability)? UserTypeProjection<'tcx>,
                                      location: Location) {
                 self.super_ascribe_user_ty(place, variance, user_ty, location);
             }
 
             fn visit_retag(&mut self,
-                           kind: & $($mutability)* RetagKind,
-                           place: & $($mutability)* Place<'tcx>,
+                           kind: & $($mutability)? RetagKind,
+                           place: & $($mutability)? Place<'tcx>,
                            location: Location) {
                 self.super_retag(kind, place, location);
             }
 
             fn visit_place(&mut self,
-                            place: & $($mutability)* Place<'tcx>,
+                            place: & $($mutability)? Place<'tcx>,
                             context: PlaceContext<'tcx>,
                             location: Location) {
                 self.super_place(place, context, location);
             }
 
             fn visit_static(&mut self,
-                            static_: & $($mutability)* Static<'tcx>,
+                            static_: & $($mutability)? Static<'tcx>,
                             context: PlaceContext<'tcx>,
                             location: Location) {
                 self.super_static(static_, context, location);
             }
 
             fn visit_projection(&mut self,
-                                place: & $($mutability)* PlaceProjection<'tcx>,
+                                place: & $($mutability)? PlaceProjection<'tcx>,
                                 context: PlaceContext<'tcx>,
                                 location: Location) {
                 self.super_projection(place, context, location);
             }
 
             fn visit_projection_elem(&mut self,
-                                     place: & $($mutability)* PlaceElem<'tcx>,
+                                     place: & $($mutability)? PlaceElem<'tcx>,
                                      location: Location) {
                 self.super_projection_elem(place, location);
             }
@@ -184,36 +183,36 @@ macro_rules! make_mir_visitor {
             }
 
             fn visit_constant(&mut self,
-                              constant: & $($mutability)* Constant<'tcx>,
+                              constant: & $($mutability)? Constant<'tcx>,
                               location: Location) {
                 self.super_constant(constant, location);
             }
 
             fn visit_def_id(&mut self,
-                            def_id: & $($mutability)* DefId,
+                            def_id: & $($mutability)? DefId,
                             _: Location) {
                 self.super_def_id(def_id);
             }
 
             fn visit_span(&mut self,
-                          span: & $($mutability)* Span) {
+                          span: & $($mutability)? Span) {
                 self.super_span(span);
             }
 
             fn visit_source_info(&mut self,
-                                 source_info: & $($mutability)* SourceInfo) {
+                                 source_info: & $($mutability)? SourceInfo) {
                 self.super_source_info(source_info);
             }
 
             fn visit_ty(&mut self,
-                        ty: & $($mutability)* Ty<'tcx>,
+                        ty: & $($mutability)? Ty<'tcx>,
                         _: TyContext) {
                 self.super_ty(ty);
             }
 
             fn visit_user_type_projection(
                 &mut self,
-                ty: & $($mutability)* UserTypeProjection<'tcx>,
+                ty: & $($mutability)? UserTypeProjection<'tcx>,
             ) {
                 self.super_user_type_projection(ty);
             }
@@ -221,55 +220,55 @@ macro_rules! make_mir_visitor {
             fn visit_user_type_annotation(
                 &mut self,
                 index: UserTypeAnnotationIndex,
-                ty: & $($mutability)* Canonical<'tcx, UserTypeAnnotation<'tcx>>,
+                ty: & $($mutability)? CanonicalUserTypeAnnotation<'tcx>,
             ) {
                 self.super_user_type_annotation(index, ty);
             }
 
             fn visit_region(&mut self,
-                            region: & $($mutability)* ty::Region<'tcx>,
+                            region: & $($mutability)? ty::Region<'tcx>,
                             _: Location) {
                 self.super_region(region);
             }
 
             fn visit_const(&mut self,
-                           constant: & $($mutability)* &'tcx ty::LazyConst<'tcx>,
+                           constant: & $($mutability)? &'tcx ty::LazyConst<'tcx>,
                            _: Location) {
                 self.super_const(constant);
             }
 
             fn visit_substs(&mut self,
-                            substs: & $($mutability)* &'tcx Substs<'tcx>,
+                            substs: & $($mutability)? &'tcx Substs<'tcx>,
                             _: Location) {
                 self.super_substs(substs);
             }
 
             fn visit_closure_substs(&mut self,
-                                    substs: & $($mutability)* ClosureSubsts<'tcx>,
+                                    substs: & $($mutability)? ClosureSubsts<'tcx>,
                                     _: Location) {
                 self.super_closure_substs(substs);
             }
 
             fn visit_generator_substs(&mut self,
-                                      substs: & $($mutability)* GeneratorSubsts<'tcx>,
+                                      substs: & $($mutability)? GeneratorSubsts<'tcx>,
                                     _: Location) {
                 self.super_generator_substs(substs);
             }
 
             fn visit_local_decl(&mut self,
                                 local: Local,
-                                local_decl: & $($mutability)* LocalDecl<'tcx>) {
+                                local_decl: & $($mutability)? LocalDecl<'tcx>) {
                 self.super_local_decl(local, local_decl);
             }
 
             fn visit_local(&mut self,
-                            _local: & $($mutability)* Local,
+                            _local: & $($mutability)? Local,
                             _context: PlaceContext<'tcx>,
                             _location: Location) {
             }
 
             fn visit_source_scope(&mut self,
-                                      scope: & $($mutability)* SourceScope) {
+                                      scope: & $($mutability)? SourceScope) {
                 self.super_source_scope(scope);
             }
 
@@ -277,8 +276,8 @@ macro_rules! make_mir_visitor {
             // not meant to be overridden.
 
             fn super_mir(&mut self,
-                         mir: & $($mutability)* Mir<'tcx>) {
-                if let Some(yield_ty) = &$($mutability)* mir.yield_ty {
+                         mir: & $($mutability)? Mir<'tcx>) {
+                if let Some(yield_ty) = &$($mutability)? mir.yield_ty {
                     self.visit_ty(yield_ty, TyContext::YieldTy(SourceInfo {
                         span: mir.span,
                         scope: OUTERMOST_SOURCE_SCOPE,
@@ -292,42 +291,45 @@ macro_rules! make_mir_visitor {
                     (mut) => (mir.basic_blocks_mut().iter_enumerated_mut());
                     () => (mir.basic_blocks().iter_enumerated());
                 };
-                for (bb, data) in basic_blocks!($($mutability)*) {
+                for (bb, data) in basic_blocks!($($mutability)?) {
                     self.visit_basic_block_data(bb, data);
                 }
 
-                for scope in &$($mutability)* mir.source_scopes {
+                for scope in &$($mutability)? mir.source_scopes {
                     self.visit_source_scope_data(scope);
                 }
 
-                self.visit_ty(&$($mutability)* mir.return_ty(), TyContext::ReturnTy(SourceInfo {
+                self.visit_ty(&$($mutability)? mir.return_ty(), TyContext::ReturnTy(SourceInfo {
                     span: mir.span,
                     scope: OUTERMOST_SOURCE_SCOPE,
                 }));
 
                 for local in mir.local_decls.indices() {
-                    self.visit_local_decl(local, & $($mutability)* mir.local_decls[local]);
+                    self.visit_local_decl(local, & $($mutability)? mir.local_decls[local]);
                 }
 
-                for index in mir.user_type_annotations.indices() {
-                    let (span, annotation) = & $($mutability)* mir.user_type_annotations[index];
+                macro_rules! type_annotations {
+                    (mut) => (mir.user_type_annotations.iter_enumerated_mut());
+                    () => (mir.user_type_annotations.iter_enumerated());
+                };
+
+                for (index, annotation) in type_annotations!($($mutability)?) {
                     self.visit_user_type_annotation(
                         index, annotation
                     );
-                    self.visit_span(span);
                 }
 
-                self.visit_span(&$($mutability)* mir.span);
+                self.visit_span(&$($mutability)? mir.span);
             }
 
             fn super_basic_block_data(&mut self,
                                       block: BasicBlock,
-                                      data: & $($mutability)* BasicBlockData<'tcx>) {
+                                      data: & $($mutability)? BasicBlockData<'tcx>) {
                 let BasicBlockData {
-                    ref $($mutability)* statements,
-                    ref $($mutability)* terminator,
+                    statements,
+                    terminator,
                     is_cleanup: _
-                } = *data;
+                } = data;
 
                 let mut index = 0;
                 for statement in statements {
@@ -336,92 +338,83 @@ macro_rules! make_mir_visitor {
                     index += 1;
                 }
 
-                if let Some(ref $($mutability)* terminator) = *terminator {
+                if let Some(terminator) = terminator {
                     let location = Location { block: block, statement_index: index };
                     self.visit_terminator(block, terminator, location);
                 }
             }
 
-            fn super_source_scope_data(&mut self,
-                                           scope_data: & $($mutability)* SourceScopeData) {
+            fn super_source_scope_data(&mut self, scope_data: & $($mutability)? SourceScopeData) {
                 let SourceScopeData {
-                    ref $($mutability)* span,
-                    ref $($mutability)* parent_scope,
-                } = *scope_data;
+                    span,
+                    parent_scope,
+                } = scope_data;
 
                 self.visit_span(span);
-                if let Some(ref $($mutability)* parent_scope) = *parent_scope {
+                if let Some(parent_scope) = parent_scope {
                     self.visit_source_scope(parent_scope);
                 }
             }
 
             fn super_statement(&mut self,
                                block: BasicBlock,
-                               statement: & $($mutability)* Statement<'tcx>,
+                               statement: & $($mutability)? Statement<'tcx>,
                                location: Location) {
                 let Statement {
-                    ref $($mutability)* source_info,
-                    ref $($mutability)* kind,
-                } = *statement;
+                    source_info,
+                    kind,
+                } = statement;
 
                 self.visit_source_info(source_info);
-                match *kind {
-                    StatementKind::Assign(ref $($mutability)* place,
-                                          ref $($mutability)* rvalue) => {
+                match kind {
+                    StatementKind::Assign(place, rvalue) => {
                         self.visit_assign(block, place, rvalue, location);
                     }
-                    StatementKind::FakeRead(_, ref $($mutability)* place) => {
+                    StatementKind::FakeRead(_, place) => {
                         self.visit_place(
                             place,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
                             location
                         );
                     }
-                    StatementKind::SetDiscriminant{ ref $($mutability)* place, .. } => {
+                    StatementKind::SetDiscriminant { place, .. } => {
                         self.visit_place(
                             place,
                             PlaceContext::MutatingUse(MutatingUseContext::Store),
                             location
                         );
                     }
-                    StatementKind::StorageLive(ref $($mutability)* local) => {
+                    StatementKind::StorageLive(local) => {
                         self.visit_local(
                             local,
                             PlaceContext::NonUse(NonUseContext::StorageLive),
                             location
                         );
                     }
-                    StatementKind::StorageDead(ref $($mutability)* local) => {
+                    StatementKind::StorageDead(local) => {
                         self.visit_local(
                             local,
                             PlaceContext::NonUse(NonUseContext::StorageDead),
                             location
                         );
                     }
-                    StatementKind::InlineAsm { ref $($mutability)* outputs,
-                                               ref $($mutability)* inputs,
-                                               asm: _ } => {
-                        for output in & $($mutability)* outputs[..] {
+                    StatementKind::InlineAsm { outputs, inputs, asm: _ } => {
+                        for output in & $($mutability)? outputs[..] {
                             self.visit_place(
                                 output,
                                 PlaceContext::MutatingUse(MutatingUseContext::AsmOutput),
                                 location
                             );
                         }
-                        for (span, input) in & $($mutability)* inputs[..] {
+                        for (span, input) in & $($mutability)? inputs[..] {
                             self.visit_span(span);
                             self.visit_operand(input, location);
                         }
                     }
-                    StatementKind::Retag ( ref $($mutability)* kind,
-                                           ref $($mutability)* place ) => {
+                    StatementKind::Retag(kind, place) => {
                         self.visit_retag(kind, place, location);
                     }
-                    StatementKind::AscribeUserType(
-                        ref $($mutability)* place,
-                        ref $($mutability)* variance,
-                        ref $($mutability)* user_ty,
-                    ) => {
+                    StatementKind::AscribeUserType(place, variance, user_ty) => {
                         self.visit_ascribe_user_ty(place, variance, user_ty, location);
                     }
                     StatementKind::Nop => {}
@@ -430,8 +423,8 @@ macro_rules! make_mir_visitor {
 
             fn super_assign(&mut self,
                             _block: BasicBlock,
-                            place: &$($mutability)* Place<'tcx>,
-                            rvalue: &$($mutability)* Rvalue<'tcx>,
+                            place: &$($mutability)? Place<'tcx>,
+                            rvalue: &$($mutability)? Rvalue<'tcx>,
                             location: Location) {
                 self.visit_place(
                     place,
@@ -443,12 +436,9 @@ macro_rules! make_mir_visitor {
 
             fn super_terminator(&mut self,
                                 block: BasicBlock,
-                                terminator: &$($mutability)* Terminator<'tcx>,
+                                terminator: &$($mutability)? Terminator<'tcx>,
                                 location: Location) {
-                let Terminator {
-                    ref $($mutability)* source_info,
-                    ref $($mutability)* kind,
-                } = *terminator;
+                let Terminator { source_info, kind } = terminator;
 
                 self.visit_source_info(source_info);
                 self.visit_terminator_kind(block, kind, location);
@@ -456,21 +446,23 @@ macro_rules! make_mir_visitor {
 
             fn super_terminator_kind(&mut self,
                                      block: BasicBlock,
-                                     kind: & $($mutability)* TerminatorKind<'tcx>,
+                                     kind: & $($mutability)? TerminatorKind<'tcx>,
                                      source_location: Location) {
-                match *kind {
+                match kind {
                     TerminatorKind::Goto { target } => {
-                        self.visit_branch(block, target);
+                        self.visit_branch(block, *target);
                     }
 
-                    TerminatorKind::SwitchInt { ref $($mutability)* discr,
-                                                ref $($mutability)* switch_ty,
-                                                values: _,
-                                                ref targets } => {
+                    TerminatorKind::SwitchInt {
+                        discr,
+                        switch_ty,
+                        values: _,
+                        targets
+                    } => {
                         self.visit_operand(discr, source_location);
                         self.visit_ty(switch_ty, TyContext::Location(source_location));
-                        for &target in targets {
-                            self.visit_branch(block, target);
+                        for target in targets {
+                            self.visit_branch(block, *target);
                         }
                     }
 
@@ -481,113 +473,120 @@ macro_rules! make_mir_visitor {
                     TerminatorKind::Unreachable => {
                     }
 
-                    TerminatorKind::Drop { ref $($mutability)* location,
-                                           target,
-                                           unwind } => {
+                    TerminatorKind::Drop {
+                        location,
+                        target,
+                        unwind,
+                    } => {
                         self.visit_place(
                             location,
                             PlaceContext::MutatingUse(MutatingUseContext::Drop),
                             source_location
                         );
-                        self.visit_branch(block, target);
+                        self.visit_branch(block, *target);
                         unwind.map(|t| self.visit_branch(block, t));
                     }
 
-                    TerminatorKind::DropAndReplace { ref $($mutability)* location,
-                                                     ref $($mutability)* value,
-                                                     target,
-                                                     unwind } => {
+                    TerminatorKind::DropAndReplace {
+                        location,
+                        value,
+                        target,
+                        unwind,
+                    } => {
                         self.visit_place(
                             location,
                             PlaceContext::MutatingUse(MutatingUseContext::Drop),
                             source_location
                         );
                         self.visit_operand(value, source_location);
-                        self.visit_branch(block, target);
+                        self.visit_branch(block, *target);
                         unwind.map(|t| self.visit_branch(block, t));
                     }
 
-                    TerminatorKind::Call { ref $($mutability)* func,
-                                           ref $($mutability)* args,
-                                           ref $($mutability)* destination,
-                                           cleanup,
-                                           from_hir_call: _, } => {
+                    TerminatorKind::Call {
+                        func,
+                        args,
+                        destination,
+                        cleanup,
+                        from_hir_call: _,
+                    } => {
                         self.visit_operand(func, source_location);
                         for arg in args {
                             self.visit_operand(arg, source_location);
                         }
-                        if let Some((ref $($mutability)* destination, target)) = *destination {
+                        if let Some((destination, target)) = destination {
                             self.visit_place(
                                 destination,
                                 PlaceContext::MutatingUse(MutatingUseContext::Call),
                                 source_location
                             );
-                            self.visit_branch(block, target);
+                            self.visit_branch(block, *target);
                         }
                         cleanup.map(|t| self.visit_branch(block, t));
                     }
 
-                    TerminatorKind::Assert { ref $($mutability)* cond,
-                                             expected: _,
-                                             ref $($mutability)* msg,
-                                             target,
-                                             cleanup } => {
+                    TerminatorKind::Assert {
+                        cond,
+                        expected: _,
+                        msg,
+                        target,
+                        cleanup,
+                    } => {
                         self.visit_operand(cond, source_location);
                         self.visit_assert_message(msg, source_location);
-                        self.visit_branch(block, target);
+                        self.visit_branch(block, *target);
                         cleanup.map(|t| self.visit_branch(block, t));
                     }
 
-                    TerminatorKind::Yield { ref $($mutability)* value,
-                                              resume,
-                                              drop } => {
+                    TerminatorKind::Yield {
+                        value,
+                        resume,
+                        drop,
+                    } => {
                         self.visit_operand(value, source_location);
-                        self.visit_branch(block, resume);
+                        self.visit_branch(block, *resume);
                         drop.map(|t| self.visit_branch(block, t));
                     }
 
-                    TerminatorKind::FalseEdges { real_target, ref imaginary_targets} => {
-                        self.visit_branch(block, real_target);
+                    TerminatorKind::FalseEdges { real_target, imaginary_targets } => {
+                        self.visit_branch(block, *real_target);
                         for target in imaginary_targets {
                             self.visit_branch(block, *target);
                         }
                     }
 
                     TerminatorKind::FalseUnwind { real_target, unwind } => {
-                        self.visit_branch(block, real_target);
+                        self.visit_branch(block, *real_target);
                         if let Some(unwind) = unwind {
-                            self.visit_branch(block, unwind);
+                            self.visit_branch(block, *unwind);
                         }
                     }
                 }
             }
 
             fn super_assert_message(&mut self,
-                                    msg: & $($mutability)* AssertMessage<'tcx>,
+                                    msg: & $($mutability)? AssertMessage<'tcx>,
                                     location: Location) {
-                use mir::interpret::EvalErrorKind::*;
-                if let BoundsCheck {
-                        ref $($mutability)* len,
-                        ref $($mutability)* index
-                    } = *msg {
+                use crate::mir::interpret::EvalErrorKind::*;
+                if let BoundsCheck { len, index } = msg {
                     self.visit_operand(len, location);
                     self.visit_operand(index, location);
                 }
             }
 
             fn super_rvalue(&mut self,
-                            rvalue: & $($mutability)* Rvalue<'tcx>,
+                            rvalue: & $($mutability)? Rvalue<'tcx>,
                             location: Location) {
-                match *rvalue {
-                    Rvalue::Use(ref $($mutability)* operand) => {
+                match rvalue {
+                    Rvalue::Use(operand) => {
                         self.visit_operand(operand, location);
                     }
 
-                    Rvalue::Repeat(ref $($mutability)* value, _) => {
+                    Rvalue::Repeat(value, _) => {
                         self.visit_operand(value, location);
                     }
 
-                    Rvalue::Ref(ref $($mutability)* r, bk, ref $($mutability)* path) => {
+                    Rvalue::Ref(r, bk, path) => {
                         self.visit_region(r, location);
                         let ctx = match bk {
                             BorrowKind::Shared => PlaceContext::NonMutatingUse(
@@ -605,7 +604,7 @@ macro_rules! make_mir_visitor {
                         self.visit_place(path, ctx, location);
                     }
 
-                    Rvalue::Len(ref $($mutability)* path) => {
+                    Rvalue::Len(path) => {
                         self.visit_place(
                             path,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
@@ -613,28 +612,22 @@ macro_rules! make_mir_visitor {
                         );
                     }
 
-                    Rvalue::Cast(_cast_kind,
-                                 ref $($mutability)* operand,
-                                 ref $($mutability)* ty) => {
+                    Rvalue::Cast(_cast_kind, operand, ty) => {
                         self.visit_operand(operand, location);
                         self.visit_ty(ty, TyContext::Location(location));
                     }
 
-                    Rvalue::BinaryOp(_bin_op,
-                                     ref $($mutability)* lhs,
-                                     ref $($mutability)* rhs) |
-                    Rvalue::CheckedBinaryOp(_bin_op,
-                                     ref $($mutability)* lhs,
-                                     ref $($mutability)* rhs) => {
+                    Rvalue::BinaryOp(_bin_op, lhs, rhs)
+                    | Rvalue::CheckedBinaryOp(_bin_op, lhs, rhs) => {
                         self.visit_operand(lhs, location);
                         self.visit_operand(rhs, location);
                     }
 
-                    Rvalue::UnaryOp(_un_op, ref $($mutability)* op) => {
+                    Rvalue::UnaryOp(_un_op, op) => {
                         self.visit_operand(op, location);
                     }
 
-                    Rvalue::Discriminant(ref $($mutability)* place) => {
+                    Rvalue::Discriminant(place) => {
                         self.visit_place(
                             place,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
@@ -642,34 +635,39 @@ macro_rules! make_mir_visitor {
                         );
                     }
 
-                    Rvalue::NullaryOp(_op, ref $($mutability)* ty) => {
+                    Rvalue::NullaryOp(_op, ty) => {
                         self.visit_ty(ty, TyContext::Location(location));
                     }
 
-                    Rvalue::Aggregate(ref $($mutability)* kind,
-                                      ref $($mutability)* operands) => {
-                        let kind = &$($mutability)* **kind;
-                        match *kind {
-                            AggregateKind::Array(ref $($mutability)* ty) => {
+                    Rvalue::Aggregate(kind, operands) => {
+                        let kind = &$($mutability)? **kind;
+                        match kind {
+                            AggregateKind::Array(ty) => {
                                 self.visit_ty(ty, TyContext::Location(location));
                             }
                             AggregateKind::Tuple => {
                             }
-                            AggregateKind::Adt(_adt_def,
-                                               _variant_index,
-                                               ref $($mutability)* substs,
-                                               _user_substs,
-                                               _active_field_index) => {
+                            AggregateKind::Adt(
+                                _adt_def,
+                                _variant_index,
+                                substs,
+                                _user_substs,
+                                _active_field_index
+                            ) => {
                                 self.visit_substs(substs, location);
                             }
-                            AggregateKind::Closure(ref $($mutability)* def_id,
-                                                   ref $($mutability)* closure_substs) => {
+                            AggregateKind::Closure(
+                                def_id,
+                                closure_substs
+                            ) => {
                                 self.visit_def_id(def_id, location);
                                 self.visit_closure_substs(closure_substs, location);
                             }
-                            AggregateKind::Generator(ref $($mutability)* def_id,
-                                                     ref $($mutability)* generator_substs,
-                                                     _movability) => {
+                            AggregateKind::Generator(
+                                def_id,
+                                generator_substs,
+                                _movability,
+                            ) => {
                                 self.visit_def_id(def_id, location);
                                 self.visit_generator_substs(generator_substs, location);
                             }
@@ -683,33 +681,33 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_operand(&mut self,
-                             operand: & $($mutability)* Operand<'tcx>,
+                             operand: & $($mutability)? Operand<'tcx>,
                              location: Location) {
-                match *operand {
-                    Operand::Copy(ref $($mutability)* place) => {
+                match operand {
+                    Operand::Copy(place) => {
                         self.visit_place(
                             place,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy),
                             location
                         );
                     }
-                    Operand::Move(ref $($mutability)* place) => {
+                    Operand::Move(place) => {
                         self.visit_place(
                             place,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Move),
                             location
                         );
                     }
-                    Operand::Constant(ref $($mutability)* constant) => {
+                    Operand::Constant(constant) => {
                         self.visit_constant(constant, location);
                     }
                 }
             }
 
             fn super_ascribe_user_ty(&mut self,
-                                     place: & $($mutability)* Place<'tcx>,
-                                     _variance: & $($mutability)* ty::Variance,
-                                     user_ty: & $($mutability)* UserTypeProjection<'tcx>,
+                                     place: & $($mutability)? Place<'tcx>,
+                                     _variance: & $($mutability)? ty::Variance,
+                                     user_ty: & $($mutability)? UserTypeProjection<'tcx>,
                                      location: Location) {
                 self.visit_place(
                     place,
@@ -720,8 +718,8 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_retag(&mut self,
-                           _kind: & $($mutability)* RetagKind,
-                           place: & $($mutability)* Place<'tcx>,
+                           _kind: & $($mutability)? RetagKind,
+                           place: & $($mutability)? Place<'tcx>,
                            location: Location) {
                 self.visit_place(
                     place,
@@ -731,45 +729,39 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_place(&mut self,
-                            place: & $($mutability)* Place<'tcx>,
+                            place: & $($mutability)? Place<'tcx>,
                             context: PlaceContext<'tcx>,
                             location: Location) {
-                match *place {
-                    Place::Local(ref $($mutability)* local) => {
+                match place {
+                    Place::Local(local) => {
                         self.visit_local(local, context, location);
                     }
-                    Place::Static(ref $($mutability)* static_) => {
+                    Place::Static(static_) => {
                         self.visit_static(static_, context, location);
                     }
-                    Place::Promoted(ref $($mutability)* promoted) => {
-                        self.visit_ty(& $($mutability)* promoted.1, TyContext::Location(location));
+                    Place::Promoted(promoted) => {
+                        self.visit_ty(& $($mutability)? promoted.1, TyContext::Location(location));
                     },
-                    Place::Projection(ref $($mutability)* proj) => {
+                    Place::Projection(proj) => {
                         self.visit_projection(proj, context, location);
                     }
                 }
             }
 
             fn super_static(&mut self,
-                            static_: & $($mutability)* Static<'tcx>,
+                            static_: & $($mutability)? Static<'tcx>,
                             _context: PlaceContext<'tcx>,
                             location: Location) {
-                let Static {
-                    ref $($mutability)* def_id,
-                    ref $($mutability)* ty,
-                } = *static_;
+                let Static { def_id, ty } = static_;
                 self.visit_def_id(def_id, location);
                 self.visit_ty(ty, TyContext::Location(location));
             }
 
             fn super_projection(&mut self,
-                                proj: & $($mutability)* PlaceProjection<'tcx>,
+                                proj: & $($mutability)? PlaceProjection<'tcx>,
                                 context: PlaceContext<'tcx>,
                                 location: Location) {
-                let Projection {
-                    ref $($mutability)* base,
-                    ref $($mutability)* elem,
-                } = *proj;
+                let Projection { base, elem } = proj;
                 let context = if context.is_mutating_use() {
                     PlaceContext::MutatingUse(MutatingUseContext::Projection)
                 } else {
@@ -780,17 +772,17 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_projection_elem(&mut self,
-                                     proj: & $($mutability)* PlaceElem<'tcx>,
+                                     proj: & $($mutability)? PlaceElem<'tcx>,
                                      location: Location) {
-                match *proj {
+                match proj {
                     ProjectionElem::Deref => {
                     }
                     ProjectionElem::Subslice { from: _, to: _ } => {
                     }
-                    ProjectionElem::Field(_field, ref $($mutability)* ty) => {
+                    ProjectionElem::Field(_field, ty) => {
                         self.visit_ty(ty, TyContext::Location(location));
                     }
-                    ProjectionElem::Index(ref $($mutability)* local) => {
+                    ProjectionElem::Index(local) => {
                         self.visit_local(
                             local,
                             PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy),
@@ -808,24 +800,24 @@ macro_rules! make_mir_visitor {
 
             fn super_local_decl(&mut self,
                                 local: Local,
-                                local_decl: & $($mutability)* LocalDecl<'tcx>) {
+                                local_decl: & $($mutability)? LocalDecl<'tcx>) {
                 let LocalDecl {
                     mutability: _,
-                    ref $($mutability)* ty,
-                    ref $($mutability)* user_ty,
+                    ty,
+                    user_ty,
                     name: _,
-                    ref $($mutability)* source_info,
-                    ref $($mutability)* visibility_scope,
+                    source_info,
+                    visibility_scope,
                     internal: _,
                     is_user_variable: _,
                     is_block_tail: _,
-                } = *local_decl;
+                } = local_decl;
 
                 self.visit_ty(ty, TyContext::LocalDecl {
                     local,
                     source_info: *source_info,
                 });
-                for (user_ty, _) in & $($mutability)* user_ty.contents {
+                for (user_ty, _) in & $($mutability)? user_ty.contents {
                     self.visit_user_type_projection(user_ty);
                 }
                 self.visit_source_info(source_info);
@@ -833,7 +825,7 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_source_scope(&mut self,
-                                      _scope: & $($mutability)* SourceScope) {
+                                      _scope: & $($mutability)? SourceScope) {
             }
 
             fn super_branch(&mut self,
@@ -842,14 +834,14 @@ macro_rules! make_mir_visitor {
             }
 
             fn super_constant(&mut self,
-                              constant: & $($mutability)* Constant<'tcx>,
+                              constant: & $($mutability)? Constant<'tcx>,
                               location: Location) {
                 let Constant {
-                    ref $($mutability)* span,
-                    ref $($mutability)* ty,
-                    ref $($mutability)* user_ty,
-                    ref $($mutability)* literal,
-                } = *constant;
+                    span,
+                    ty,
+                    user_ty,
+                    literal,
+                } = constant;
 
                 self.visit_span(span);
                 self.visit_ty(ty, TyContext::Location(location));
@@ -857,17 +849,17 @@ macro_rules! make_mir_visitor {
                 self.visit_const(literal, location);
             }
 
-            fn super_def_id(&mut self, _def_id: & $($mutability)* DefId) {
+            fn super_def_id(&mut self, _def_id: & $($mutability)? DefId) {
             }
 
-            fn super_span(&mut self, _span: & $($mutability)* Span) {
+            fn super_span(&mut self, _span: & $($mutability)? Span) {
             }
 
-            fn super_source_info(&mut self, source_info: & $($mutability)* SourceInfo) {
+            fn super_source_info(&mut self, source_info: & $($mutability)? SourceInfo) {
                 let SourceInfo {
-                    ref $($mutability)* span,
-                    ref $($mutability)* scope,
-                } = *source_info;
+                    span,
+                    scope,
+                } = source_info;
 
                 self.visit_span(span);
                 self.visit_source_scope(scope);
@@ -875,47 +867,49 @@ macro_rules! make_mir_visitor {
 
             fn super_user_type_projection(
                 &mut self,
-                _ty: & $($mutability)* UserTypeProjection<'tcx>,
+                _ty: & $($mutability)? UserTypeProjection<'tcx>,
             ) {
             }
 
             fn super_user_type_annotation(
                 &mut self,
                 _index: UserTypeAnnotationIndex,
-                _ty: & $($mutability)* Canonical<'tcx, UserTypeAnnotation<'tcx>>,
+                ty: & $($mutability)? CanonicalUserTypeAnnotation<'tcx>,
             ) {
+                self.visit_span(& $($mutability)? ty.span);
+                self.visit_ty(& $($mutability)? ty.inferred_ty, TyContext::UserTy(ty.span));
             }
 
-            fn super_ty(&mut self, _ty: & $($mutability)* Ty<'tcx>) {
+            fn super_ty(&mut self, _ty: & $($mutability)? Ty<'tcx>) {
             }
 
-            fn super_region(&mut self, _region: & $($mutability)* ty::Region<'tcx>) {
+            fn super_region(&mut self, _region: & $($mutability)? ty::Region<'tcx>) {
             }
 
-            fn super_const(&mut self, _const: & $($mutability)* &'tcx ty::LazyConst<'tcx>) {
+            fn super_const(&mut self, _const: & $($mutability)? &'tcx ty::LazyConst<'tcx>) {
             }
 
-            fn super_substs(&mut self, _substs: & $($mutability)* &'tcx Substs<'tcx>) {
+            fn super_substs(&mut self, _substs: & $($mutability)? &'tcx Substs<'tcx>) {
             }
 
             fn super_generator_substs(&mut self,
-                                      _substs: & $($mutability)* GeneratorSubsts<'tcx>) {
+                                      _substs: & $($mutability)? GeneratorSubsts<'tcx>) {
             }
 
             fn super_closure_substs(&mut self,
-                                    _substs: & $($mutability)* ClosureSubsts<'tcx>) {
+                                    _substs: & $($mutability)? ClosureSubsts<'tcx>) {
             }
 
             // Convenience methods
 
-            fn visit_location(&mut self, mir: & $($mutability)* Mir<'tcx>, location: Location) {
-                let basic_block = & $($mutability)* mir[location.block];
+            fn visit_location(&mut self, mir: & $($mutability)? Mir<'tcx>, location: Location) {
+                let basic_block = & $($mutability)? mir[location.block];
                 if basic_block.statements.len() == location.statement_index {
-                    if let Some(ref $($mutability)* terminator) = basic_block.terminator {
+                    if let Some(ref $($mutability)? terminator) = basic_block.terminator {
                         self.visit_terminator(location.block, terminator, location)
                     }
                 } else {
-                    let statement = & $($mutability)*
+                    let statement = & $($mutability)?
                         basic_block.statements[location.statement_index];
                     self.visit_statement(location.block, statement, location)
                 }
@@ -964,6 +958,9 @@ pub enum TyContext {
         source_info: SourceInfo,
     },
 
+    /// The inferred type of a user type annotation.
+    UserTy(Span),
+
     /// The return type of the function.
     ReturnTy(SourceInfo),
 
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 42adc6a87fdba..65da458efbfff 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -3,13 +3,13 @@
 
 use std::str::FromStr;
 
-use session::{early_error, early_warn, Session};
-use session::search_paths::SearchPath;
+use crate::session::{early_error, early_warn, Session};
+use crate::session::search_paths::SearchPath;
 
-use rustc_target::spec::{LinkerFlavor, PanicStrategy, RelroLevel};
+use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
 use rustc_target::spec::{Target, TargetTriple};
-use lint;
-use middle::cstore;
+use crate::lint;
+use crate::middle::cstore;
 
 use syntax::ast::{self, IntTy, UintTy, MetaItemKind};
 use syntax::source_map::{FileName, FilePathMapping};
@@ -58,6 +58,8 @@ pub enum OptLevel {
     SizeMin,    // -Oz
 }
 
+impl_stable_hash_via_hash!(OptLevel);
+
 /// This is what the `LtoCli` values get mapped to after resolving defaults and
 /// and taking other command line options into account.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
@@ -94,18 +96,18 @@ pub enum LtoCli {
 }
 
 #[derive(Clone, PartialEq, Hash)]
-pub enum CrossLangLto {
+pub enum LinkerPluginLto {
     LinkerPlugin(PathBuf),
     LinkerPluginAuto,
     Disabled
 }
 
-impl CrossLangLto {
+impl LinkerPluginLto {
     pub fn enabled(&self) -> bool {
         match *self {
-            CrossLangLto::LinkerPlugin(_) |
-            CrossLangLto::LinkerPluginAuto => true,
-            CrossLangLto::Disabled => false,
+            LinkerPluginLto::LinkerPlugin(_) |
+            LinkerPluginLto::LinkerPluginAuto => true,
+            LinkerPluginLto::Disabled => false,
         }
     }
 }
@@ -409,6 +411,10 @@ top_level_options!(
         remap_path_prefix: Vec<(PathBuf, PathBuf)> [UNTRACKED],
 
         edition: Edition [TRACKED],
+
+        // The list of crates to consider private when
+        // checking leaked private dependency types in public interfaces
+        extern_private: Vec<String> [TRACKED],
     }
 );
 
@@ -469,7 +475,7 @@ impl BorrowckMode {
 }
 
 pub enum Input {
-    /// Load source from file
+    /// Loads source from file
     File(PathBuf),
     Str {
         /// String that is shown in place of a filename
@@ -517,7 +523,7 @@ impl OutputFilenames {
             .unwrap_or_else(|| self.temp_path(flavor, None))
     }
 
-    /// Get the path where a compilation artifact of the given type for the
+    /// Gets the path where a compilation artifact of the given type for the
     /// given codegen unit should be placed on disk. If codegen_unit_name is
     /// None, a path distinct from those of any codegen unit will be generated.
     pub fn temp_path(&self, flavor: OutputType, codegen_unit_name: Option<&str>) -> PathBuf {
@@ -526,7 +532,7 @@ impl OutputFilenames {
     }
 
     /// Like temp_path, but also supports things where there is no corresponding
-    /// OutputType, like no-opt-bitcode or lto-bitcode.
+    /// OutputType, like noopt-bitcode or lto-bitcode.
     pub fn temp_path_ext(&self, ext: &str, codegen_unit_name: Option<&str>) -> PathBuf {
         let base = self.out_directory.join(&self.filestem());
 
@@ -604,12 +610,13 @@ impl Default for Options {
             cli_forced_thinlto_off: false,
             remap_path_prefix: Vec::new(),
             edition: DEFAULT_EDITION,
+            extern_private: Vec::new()
         }
     }
 }
 
 impl Options {
-    /// True if there is a reason to build the dep graph.
+    /// Returns `true` if there is a reason to build the dep graph.
     pub fn build_dep_graph(&self) -> bool {
         self.incremental.is_some() || self.debugging_opts.dump_dep_graph
             || self.debugging_opts.query_dep_graph
@@ -625,7 +632,7 @@ impl Options {
         FilePathMapping::new(self.remap_path_prefix.clone())
     }
 
-    /// True if there will be an output file generated
+    /// Returns `true` if there will be an output file generated
     pub fn will_create_output_file(&self) -> bool {
         !self.debugging_opts.parse_only && // The file is just being parsed
             !self.debugging_opts.ls // The file is just being queried
@@ -649,15 +656,15 @@ impl Options {
     }
 }
 
-// The type of entry function, so
-// users can have their own entry
-// functions
-#[derive(Copy, Clone, PartialEq)]
+// The type of entry function, so users can have their own entry functions
+#[derive(Copy, Clone, PartialEq, Hash, Debug)]
 pub enum EntryFnType {
     Main,
     Start,
 }
 
+impl_stable_hash_via_hash!(EntryFnType);
+
 #[derive(Copy, PartialEq, PartialOrd, Clone, Ord, Eq, Hash, Debug)]
 pub enum CrateType {
     Executable,
@@ -805,16 +812,19 @@ macro_rules! options {
         pub const parse_lto: Option<&str> =
             Some("either a boolean (`yes`, `no`, `on`, `off`, etc), `thin`, \
                   `fat`, or omitted");
-        pub const parse_cross_lang_lto: Option<&str> =
+        pub const parse_linker_plugin_lto: Option<&str> =
             Some("either a boolean (`yes`, `no`, `on`, `off`, etc), \
                   or the path to the linker plugin");
+        pub const parse_merge_functions: Option<&str> =
+            Some("one of: `disabled`, `trampolines`, or `aliases`");
     }
 
     #[allow(dead_code)]
     mod $mod_set {
-        use super::{$struct_name, Passes, Sanitizer, LtoCli, CrossLangLto};
-        use rustc_target::spec::{LinkerFlavor, PanicStrategy, RelroLevel};
+        use super::{$struct_name, Passes, Sanitizer, LtoCli, LinkerPluginLto};
+        use rustc_target::spec::{LinkerFlavor, MergeFunctions, PanicStrategy, RelroLevel};
         use std::path::PathBuf;
+        use std::str::FromStr;
 
         $(
             pub fn $opt(cg: &mut $struct_name, v: Option<&str>) -> bool {
@@ -1027,25 +1037,33 @@ macro_rules! options {
             true
         }
 
-        fn parse_cross_lang_lto(slot: &mut CrossLangLto, v: Option<&str>) -> bool {
+        fn parse_linker_plugin_lto(slot: &mut LinkerPluginLto, v: Option<&str>) -> bool {
             if v.is_some() {
                 let mut bool_arg = None;
                 if parse_opt_bool(&mut bool_arg, v) {
                     *slot = if bool_arg.unwrap() {
-                        CrossLangLto::LinkerPluginAuto
+                        LinkerPluginLto::LinkerPluginAuto
                     } else {
-                        CrossLangLto::Disabled
+                        LinkerPluginLto::Disabled
                     };
                     return true
                 }
             }
 
             *slot = match v {
-                None => CrossLangLto::LinkerPluginAuto,
-                Some(path) => CrossLangLto::LinkerPlugin(PathBuf::from(path)),
+                None => LinkerPluginLto::LinkerPluginAuto,
+                Some(path) => LinkerPluginLto::LinkerPlugin(PathBuf::from(path)),
             };
             true
         }
+
+        fn parse_merge_functions(slot: &mut Option<MergeFunctions>, v: Option<&str>) -> bool {
+            match v.and_then(|s| MergeFunctions::from_str(s).ok()) {
+                Some(mergefunc) => *slot = Some(mergefunc),
+                _ => return false,
+            }
+            true
+        }
     }
 ) }
 
@@ -1127,6 +1145,10 @@ options! {CodegenOptions, CodegenSetter, basic_codegen_options,
         "allow the linker to link its default libraries"),
     linker_flavor: Option<LinkerFlavor> = (None, parse_linker_flavor, [UNTRACKED],
                                            "Linker flavor"),
+    linker_plugin_lto: LinkerPluginLto = (LinkerPluginLto::Disabled,
+        parse_linker_plugin_lto, [TRACKED],
+        "generate build artifacts that are compatible with linker-based LTO."),
+
 }
 
 options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
@@ -1181,8 +1203,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "prints the llvm optimization passes being run"),
     ast_json: bool = (false, parse_bool, [UNTRACKED],
         "print the AST as JSON and halt"),
-    query_threads: Option<usize> = (None, parse_opt_uint, [UNTRACKED],
-        "execute queries on a thread pool with N threads"),
+    threads: Option<usize> = (None, parse_opt_uint, [UNTRACKED],
+        "use a thread pool with N threads"),
     ast_json_noexpand: bool = (false, parse_bool, [UNTRACKED],
         "print the pre-expansion AST as JSON and halt"),
     ls: bool = (false, parse_bool, [UNTRACKED],
@@ -1215,6 +1237,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "show extended diagnostic help"),
     continue_parse_after_error: bool = (false, parse_bool, [TRACKED],
         "attempt to recover from parse errors (experimental)"),
+    dep_tasks: bool = (false, parse_bool, [UNTRACKED],
+        "print tasks that execute and the color their dep node gets (requires debug build)"),
     incremental: Option<String> = (None, parse_opt_string, [UNTRACKED],
         "enable incremental compilation (experimental)"),
     incremental_queries: bool = (true, parse_bool, [UNTRACKED],
@@ -1287,6 +1311,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "print some statistics about AST and HIR"),
     always_encode_mir: bool = (false, parse_bool, [TRACKED],
         "encode MIR of all functions into the crate metadata"),
+    unleash_the_miri_inside_of_you: bool = (false, parse_bool, [TRACKED],
+        "take the breaks off const evaluation. NOTE: this is unsound"),
     osx_rpath_install_name: bool = (false, parse_bool, [TRACKED],
         "pass `-install_name @rpath/...` to the macOS linker"),
     sanitizer: Option<Sanitizer> = (None, parse_sanitizer, [TRACKED],
@@ -1342,10 +1368,15 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
     unpretty: Option<String> = (None, parse_unpretty, [UNTRACKED],
         "Present the input source, unstable (and less-pretty) variants;
         valid types are any of the types for `--pretty`, as well as:
+        `expanded`, `expanded,identified`,
+        `expanded,hygiene` (with internal representations),
         `flowgraph=<nodeid>` (graphviz formatted flowgraph for node),
+        `flowgraph,unlabelled=<nodeid>` (unlabelled graphviz formatted flowgraph for node),
         `everybody_loops` (all function bodies replaced with `loop {}`),
-        `hir` (the HIR), `hir,identified`, or
-        `hir,typed` (HIR with types for each node)."),
+        `hir` (the HIR), `hir,identified`,
+        `hir,typed` (HIR with types for each node),
+        `hir-tree` (dump the raw HIR),
+        `mir` (the MIR), or `mir-cfg` (graphviz formatted MIR)"),
     run_dsymutil: Option<bool> = (None, parse_opt_bool, [TRACKED],
         "run `dsymutil` and delete intermediate object files"),
     ui_testing: bool = (false, parse_bool, [UNTRACKED],
@@ -1358,12 +1389,12 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         "make the current crate share its generic instantiations"),
     chalk: bool = (false, parse_bool, [TRACKED],
         "enable the experimental Chalk-based trait solving engine"),
-    cross_lang_lto: CrossLangLto = (CrossLangLto::Disabled, parse_cross_lang_lto, [TRACKED],
-        "generate build artifacts that are compatible with linker-based LTO."),
     no_parallel_llvm: bool = (false, parse_bool, [UNTRACKED],
         "don't run LLVM in parallel (while keeping codegen-units and ThinLTO)"),
     no_leak_check: bool = (false, parse_bool, [UNTRACKED],
         "disables the 'leak check' for subtyping; unsound, but useful for tests"),
+    no_interleave_lints: bool = (false, parse_bool, [UNTRACKED],
+        "don't interleave execution of lints; allows benchmarking individual lints"),
     crate_attr: Vec<String> = (Vec::new(), parse_string_push, [TRACKED],
         "inject the given attribute in the crate"),
     self_profile: bool = (false, parse_bool, [UNTRACKED],
@@ -1376,6 +1407,9 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "whether to use the PLT when calling into shared libraries;
           only has effect for PIC code on systems with ELF binaries
           (default: PLT is disabled if full relro is enabled)"),
+    merge_functions: Option<MergeFunctions> = (None, parse_merge_functions, [TRACKED],
+        "control the operation of the MergeFunctions LLVM pass, taking
+         the same values as the target option of the same name"),
 }
 
 pub fn default_lib_output() -> CrateType {
@@ -1701,6 +1735,12 @@ pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
             "Specify where an external rust library is located",
             "NAME=PATH",
         ),
+        opt::multi_s(
+            "",
+            "extern-private",
+            "Specify where an extern rust library is located, marking it as a private dependency",
+            "NAME=PATH",
+        ),
         opt::opt_s("", "sysroot", "Override the system root", "PATH"),
         opt::multi("Z", "", "Set internal debugging options", "FLAG"),
         opt::opt_s(
@@ -1882,6 +1922,7 @@ pub fn build_session_options_and_crate_config(
     let crate_types = parse_crate_types_from_list(unparsed_crate_types)
         .unwrap_or_else(|e| early_error(error_format, &e[..]));
 
+
     let (lint_opts, describe_lints, lint_cap) = get_cmd_lint_options(matches, error_format);
 
     let mut debugging_opts = build_debugging_options(matches, error_format);
@@ -1963,17 +2004,17 @@ pub fn build_session_options_and_crate_config(
         }
     }
 
-    if debugging_opts.query_threads == Some(0) {
+    if debugging_opts.threads == Some(0) {
         early_error(
             error_format,
-            "Value for query threads must be a positive nonzero integer",
+            "Value for threads must be a positive nonzero integer",
         );
     }
 
-    if debugging_opts.query_threads.unwrap_or(1) > 1 && debugging_opts.fuel.is_some() {
+    if debugging_opts.threads.unwrap_or(1) > 1 && debugging_opts.fuel.is_some() {
         early_error(
             error_format,
-            "Optimization fuel is incompatible with multiple query threads",
+            "Optimization fuel is incompatible with multiple threads",
         );
     }
 
@@ -2195,8 +2236,18 @@ pub fn build_session_options_and_crate_config(
         );
     }
 
+    if matches.opt_present("extern-private") && !debugging_opts.unstable_options {
+        early_error(
+            ErrorOutputType::default(),
+            "'--extern-private' is unstable and only \
+            available for nightly builds of rustc."
+        )
+    }
+
+    let extern_private = matches.opt_strs("extern-private");
+
     let mut externs: BTreeMap<_, BTreeSet<_>> = BTreeMap::new();
-    for arg in &matches.opt_strs("extern") {
+    for arg in matches.opt_strs("extern").into_iter().chain(matches.opt_strs("extern-private")) {
         let mut parts = arg.splitn(2, '=');
         let name = parts.next().unwrap_or_else(||
             early_error(error_format, "--extern value must not be empty"));
@@ -2264,6 +2315,7 @@ pub fn build_session_options_and_crate_config(
             cli_forced_thinlto_off: disable_thinlto,
             remap_path_prefix,
             edition,
+            extern_private
         },
         cfg,
     )
@@ -2296,7 +2348,7 @@ pub mod nightly_options {
     use getopts;
     use syntax::feature_gate::UnstableFeatures;
     use super::{ErrorOutputType, OptionStability, RustcOptGroup};
-    use session::early_error;
+    use crate::session::early_error;
 
     pub fn is_unstable_enabled(matches: &getopts::Matches) -> bool {
         is_nightly_build()
@@ -2385,16 +2437,16 @@ impl fmt::Display for CrateType {
 /// we have an opt-in scheme here, so one is hopefully forced to think about
 /// how the hash should be calculated when adding a new command-line argument.
 mod dep_tracking {
-    use lint;
-    use middle::cstore;
+    use crate::lint;
+    use crate::middle::cstore;
     use std::collections::BTreeMap;
     use std::hash::Hash;
     use std::path::PathBuf;
     use std::collections::hash_map::DefaultHasher;
     use super::{CrateType, DebugInfo, ErrorOutputType, OptLevel, OutputTypes,
-                Passes, Sanitizer, LtoCli, CrossLangLto};
+                Passes, Sanitizer, LtoCli, LinkerPluginLto};
     use syntax::feature_gate::UnstableFeatures;
-    use rustc_target::spec::{PanicStrategy, RelroLevel, TargetTriple};
+    use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel, TargetTriple};
     use syntax::edition::Edition;
 
     pub trait DepTrackingHash {
@@ -2437,12 +2489,15 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(Option<usize>);
     impl_dep_tracking_hash_via_hash!(Option<String>);
     impl_dep_tracking_hash_via_hash!(Option<(String, u64)>);
+    impl_dep_tracking_hash_via_hash!(Option<Vec<String>>);
+    impl_dep_tracking_hash_via_hash!(Option<MergeFunctions>);
     impl_dep_tracking_hash_via_hash!(Option<PanicStrategy>);
     impl_dep_tracking_hash_via_hash!(Option<RelroLevel>);
     impl_dep_tracking_hash_via_hash!(Option<lint::Level>);
     impl_dep_tracking_hash_via_hash!(Option<PathBuf>);
     impl_dep_tracking_hash_via_hash!(Option<cstore::NativeLibraryKind>);
     impl_dep_tracking_hash_via_hash!(CrateType);
+    impl_dep_tracking_hash_via_hash!(MergeFunctions);
     impl_dep_tracking_hash_via_hash!(PanicStrategy);
     impl_dep_tracking_hash_via_hash!(RelroLevel);
     impl_dep_tracking_hash_via_hash!(Passes);
@@ -2456,7 +2511,7 @@ mod dep_tracking {
     impl_dep_tracking_hash_via_hash!(Option<Sanitizer>);
     impl_dep_tracking_hash_via_hash!(TargetTriple);
     impl_dep_tracking_hash_via_hash!(Edition);
-    impl_dep_tracking_hash_via_hash!(CrossLangLto);
+    impl_dep_tracking_hash_via_hash!(LinkerPluginLto);
 
     impl_dep_tracking_hash_for_sortable_vec_of!(String);
     impl_dep_tracking_hash_for_sortable_vec_of!(PathBuf);
@@ -2516,19 +2571,18 @@ mod dep_tracking {
 
 #[cfg(test)]
 mod tests {
-    use errors;
     use getopts;
-    use lint;
-    use middle::cstore;
-    use session::config::{build_configuration, build_session_options_and_crate_config};
-    use session::config::{LtoCli, CrossLangLto};
-    use session::build_session;
-    use session::search_paths::SearchPath;
+    use crate::lint;
+    use crate::middle::cstore;
+    use crate::session::config::{build_configuration, build_session_options_and_crate_config};
+    use crate::session::config::{LtoCli, LinkerPluginLto};
+    use crate::session::build_session;
+    use crate::session::search_paths::SearchPath;
     use std::collections::{BTreeMap, BTreeSet};
     use std::iter::FromIterator;
     use std::path::PathBuf;
     use super::{Externs, OutputType, OutputTypes};
-    use rustc_target::spec::{PanicStrategy, RelroLevel};
+    use rustc_target::spec::{MergeFunctions, PanicStrategy, RelroLevel};
     use syntax::symbol::Symbol;
     use syntax::edition::{Edition, DEFAULT_EDITION};
     use syntax;
@@ -3054,6 +3108,10 @@ mod tests {
         opts = reference.clone();
         opts.cg.panic = Some(PanicStrategy::Abort);
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
+
+        opts = reference.clone();
+        opts.cg.linker_plugin_lto = LinkerPluginLto::LinkerPluginAuto;
+        assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
     }
 
     #[test]
@@ -3181,7 +3239,7 @@ mod tests {
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
 
         opts = reference.clone();
-        opts.debugging_opts.cross_lang_lto = CrossLangLto::LinkerPluginAuto;
+        opts.debugging_opts.merge_functions = Some(MergeFunctions::Disabled);
         assert!(reference.dep_tracking_hash() != opts.dep_tracking_hash());
     }
 
diff --git a/src/librustc/session/filesearch.rs b/src/librustc/session/filesearch.rs
index 19f1c7a18fad1..77f190e281229 100644
--- a/src/librustc/session/filesearch.rs
+++ b/src/librustc/session/filesearch.rs
@@ -7,7 +7,7 @@ use std::env;
 use std::fs;
 use std::path::{Path, PathBuf};
 
-use session::search_paths::{SearchPath, PathKind};
+use crate::session::search_paths::{SearchPath, PathKind};
 use rustc_fs_util::fix_windows_verbatim_for_gcc;
 
 #[derive(Copy, Clone)]
diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 7363b8b3a78fa..833785f04076c 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -1,19 +1,19 @@
 pub use self::code_stats::{DataTypeKind, SizeKind, FieldInfo, VariantInfo};
 use self::code_stats::CodeStats;
 
-use dep_graph::cgu_reuse_tracker::CguReuseTracker;
-use hir::def_id::CrateNum;
+use crate::dep_graph::cgu_reuse_tracker::CguReuseTracker;
+use crate::hir::def_id::CrateNum;
 use rustc_data_structures::fingerprint::Fingerprint;
 
-use lint;
-use lint::builtin::BuiltinLintDiagnostics;
-use middle::allocator::AllocatorKind;
-use middle::dependency_format;
-use session::config::{OutputType, Lto};
-use session::search_paths::{PathKind, SearchPath};
-use util::nodemap::{FxHashMap, FxHashSet};
-use util::common::{duration_to_secs_str, ErrorReported};
-use util::common::ProfileQueriesMsg;
+use crate::lint;
+use crate::lint::builtin::BuiltinLintDiagnostics;
+use crate::middle::allocator::AllocatorKind;
+use crate::middle::dependency_format;
+use crate::session::config::OutputType;
+use crate::session::search_paths::{PathKind, SearchPath};
+use crate::util::nodemap::{FxHashMap, FxHashSet};
+use crate::util::common::{duration_to_secs_str, ErrorReported};
+use crate::util::common::ProfileQueriesMsg;
 
 use rustc_data_structures::base_n;
 use rustc_data_structures::sync::{
@@ -21,7 +21,7 @@ use rustc_data_structures::sync::{
     Ordering::SeqCst,
 };
 
-use errors::{self, DiagnosticBuilder, DiagnosticId, Applicability};
+use errors::{DiagnosticBuilder, DiagnosticId, Applicability};
 use errors::emitter::{Emitter, EmitterWriter};
 use syntax::ast::{self, NodeId};
 use syntax::edition::Edition;
@@ -30,7 +30,7 @@ use syntax::json::JsonEmitter;
 use syntax::source_map;
 use syntax::parse::{self, ParseSess};
 use syntax_pos::{MultiSpan, Span};
-use util::profiling::SelfProfiler;
+use crate::util::profiling::SelfProfiler;
 
 use rustc_target::spec::{PanicStrategy, RelroLevel, Target, TargetTriple};
 use rustc_data_structures::flock;
@@ -51,7 +51,7 @@ pub mod filesearch;
 pub mod search_paths;
 
 pub struct OptimizationFuel {
-    /// If -zfuel=crate=n is specified, initially set to n. Otherwise 0.
+    /// If `-zfuel=crate=n` is specified, initially set to `n`, otherwise `0`.
     remaining: u64,
     /// We're rejecting all further optimizations.
     out_of_fuel: bool,
@@ -64,11 +64,9 @@ pub struct Session {
     pub host: Target,
     pub opts: config::Options,
     pub host_tlib_path: SearchPath,
-    /// This is `None` if the host and target are the same.
+    /// `None` if the host and target are the same.
     pub target_tlib_path: Option<SearchPath>,
     pub parse_sess: ParseSess,
-    /// For a library crate, this is always none
-    pub entry_fn: Once<Option<(NodeId, Span, config::EntryFnType)>>,
     pub sysroot: PathBuf,
     /// The name of the root source file of the crate, in the local file system.
     /// `None` means that there is no source file.
@@ -87,7 +85,7 @@ pub struct Session {
     /// in order to avoid redundantly verbose output (Issue #24690, #44953).
     pub one_time_diagnostics: Lock<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
     pub plugin_llvm_passes: OneThread<RefCell<Vec<String>>>,
-    pub plugin_attributes: OneThread<RefCell<Vec<(String, AttributeType)>>>,
+    pub plugin_attributes: Lock<Vec<(String, AttributeType)>>,
     pub crate_types: Once<Vec<config::CrateType>>,
     pub dependency_formats: Once<dependency_format::Dependencies>,
     /// The crate_disambiguator is constructed out of all the `-C metadata`
@@ -106,7 +104,7 @@ pub struct Session {
     /// The maximum length of types during monomorphization.
     pub type_length_limit: Once<usize>,
 
-    /// The maximum number of stackframes allowed in const eval
+    /// The maximum number of stackframes allowed in const eval.
     pub const_eval_stack_frame_limit: usize,
 
     /// The metadata::creader module may inject an allocator/panic_runtime
@@ -125,13 +123,13 @@ pub struct Session {
     /// `-Zquery-dep-graph` is specified.
     pub cgu_reuse_tracker: CguReuseTracker,
 
-    /// Used by -Z profile-queries in util::common
+    /// Used by `-Z profile-queries` in `util::common`.
     pub profile_channel: Lock<Option<mpsc::Sender<ProfileQueriesMsg>>>,
 
-    /// Used by -Z self-profile
+    /// Used by `-Z self-profile`.
     pub self_profiling_active: bool,
 
-    /// Used by -Z self-profile
+    /// Used by `-Z self-profile`.
     pub self_profiling: Lock<SelfProfiler>,
 
     /// Some measurements that are being gathered during compilation.
@@ -142,14 +140,14 @@ pub struct Session {
 
     next_node_id: OneThread<Cell<ast::NodeId>>,
 
-    /// If -zfuel=crate=n is specified, Some(crate).
+    /// If `-zfuel=crate=n` is specified, `Some(crate)`.
     optimization_fuel_crate: Option<String>,
 
-    /// Tracks fuel info if If -zfuel=crate=n is specified
+    /// Tracks fuel info if `-zfuel=crate=n` is specified.
     optimization_fuel: Lock<OptimizationFuel>,
 
     // The next two are public because the driver needs to read them.
-    /// If -zprint-fuel=crate, Some(crate).
+    /// If `-zprint-fuel=crate`, `Some(crate)`.
     pub print_fuel_crate: Option<String>,
     /// Always set to zero and incremented so that we can print fuel expended by a crate.
     pub print_fuel: AtomicU64,
@@ -158,10 +156,10 @@ pub struct Session {
     /// false positives about a job server in our environment.
     pub jobserver: Client,
 
-    /// Metadata about the allocators for the current crate being compiled
+    /// Metadata about the allocators for the current crate being compiled.
     pub has_global_allocator: Once<bool>,
 
-    /// Metadata about the panic handlers for the current crate being compiled
+    /// Metadata about the panic handlers for the current crate being compiled.
     pub has_panic_handler: Once<bool>,
 
     /// Cap lint level specified by a driver specifically.
@@ -169,9 +167,9 @@ pub struct Session {
 }
 
 pub struct PerfStats {
-    /// The accumulated time spent on computing symbol hashes
+    /// The accumulated time spent on computing symbol hashes.
     pub symbol_hash_time: Lock<Duration>,
-    /// The accumulated time spent decoding def path tables from metadata
+    /// The accumulated time spent decoding def path tables from metadata.
     pub decode_def_path_tables_time: Lock<Duration>,
     /// Total number of values canonicalized queries constructed.
     pub queries_canonicalized: AtomicUsize,
@@ -437,7 +435,7 @@ impl Session {
                 }
                 DiagnosticBuilderMethod::SpanSuggestion(suggestion) => {
                     let span = span_maybe.expect("span_suggestion_* needs a span");
-                    diag_builder.span_suggestion_with_applicability(
+                    diag_builder.span_suggestion(
                         span,
                         message,
                         suggestion,
@@ -541,7 +539,7 @@ impl Session {
         self.opts.debugging_opts.print_llvm_passes
     }
 
-    /// Get the features enabled for the current compilation session.
+    /// Gets the features enabled for the current compilation session.
     /// DO NOT USE THIS METHOD if there is a TyCtxt available, as it circumvents
     /// dependency tracking. Use tcx.features() instead.
     #[inline]
@@ -879,7 +877,7 @@ impl Session {
         let mut ret = true;
         if let Some(ref c) = self.optimization_fuel_crate {
             if c == crate_name {
-                assert_eq!(self.query_threads(), 1);
+                assert_eq!(self.threads(), 1);
                 let mut fuel = self.optimization_fuel.lock();
                 ret = fuel.remaining != 0;
                 if fuel.remaining == 0 && !fuel.out_of_fuel {
@@ -892,7 +890,7 @@ impl Session {
         }
         if let Some(ref c) = self.print_fuel_crate {
             if c == crate_name {
-                assert_eq!(self.query_threads(), 1);
+                assert_eq!(self.threads(), 1);
                 self.print_fuel.fetch_add(1, SeqCst);
             }
         }
@@ -901,14 +899,14 @@ impl Session {
 
     /// Returns the number of query threads that should be used for this
     /// compilation
-    pub fn query_threads_from_opts(opts: &config::Options) -> usize {
-        opts.debugging_opts.query_threads.unwrap_or(1)
+    pub fn threads_from_opts(opts: &config::Options) -> usize {
+        opts.debugging_opts.threads.unwrap_or(::num_cpus::get())
     }
 
     /// Returns the number of query threads that should be used for this
     /// compilation
-    pub fn query_threads(&self) -> usize {
-        Self::query_threads_from_opts(&self.opts)
+    pub fn threads(&self) -> usize {
+        Self::threads_from_opts(&self.opts)
     }
 
     /// Returns the number of codegen units that should be used for this
@@ -991,7 +989,7 @@ impl Session {
         self.opts.edition
     }
 
-    /// True if we cannot skip the PLT for shared library calls.
+    /// Returns `true` if we cannot skip the PLT for shared library calls.
     pub fn needs_plt(&self) -> bool {
         // Check if the current target usually needs PLT to be enabled.
         // The user can use the command line flag to override it.
@@ -1173,8 +1171,6 @@ pub fn build_session_(
         host_tlib_path,
         target_tlib_path,
         parse_sess: p_s,
-        // For a library crate, this is always none
-        entry_fn: Once::new(),
         sysroot,
         local_crate_source_file,
         working_dir,
@@ -1182,7 +1178,7 @@ pub fn build_session_(
         buffered_lints: Lock::new(Some(Default::default())),
         one_time_diagnostics: Default::default(),
         plugin_llvm_passes: OneThread::new(RefCell::new(Vec::new())),
-        plugin_attributes: OneThread::new(RefCell::new(Vec::new())),
+        plugin_attributes: Lock::new(Vec::new()),
         crate_types: Once::new(),
         dependency_formats: Once::new(),
         crate_disambiguator: Once::new(),
@@ -1250,20 +1246,6 @@ pub fn build_session_(
 // If it is useful to have a Session available already for validating a
 // commandline argument, you can do so here.
 fn validate_commandline_args_with_session_available(sess: &Session) {
-
-    if sess.opts.incremental.is_some() {
-        match sess.lto() {
-            Lto::Thin |
-            Lto::Fat => {
-                sess.err("can't perform LTO when compiling incrementally");
-            }
-            Lto::ThinLocal |
-            Lto::No => {
-                // This is fine
-            }
-        }
-    }
-
     // Since we don't know if code in an rlib will be linked to statically or
     // dynamically downstream, rustc generates `__imp_` symbols that help the
     // MSVC linker deal with this lack of knowledge (#27438). Unfortunately,
@@ -1271,7 +1253,7 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
     // bitcode during ThinLTO. Therefore we disallow dynamic linking on MSVC
     // when compiling for LLD ThinLTO. This way we can validly just not generate
     // the `dllimport` attributes and `__imp_` symbols in that case.
-    if sess.opts.debugging_opts.cross_lang_lto.enabled() &&
+    if sess.opts.cg.linker_plugin_lto.enabled() &&
        sess.opts.cg.prefer_dynamic &&
        sess.target.target.options.is_like_msvc {
         sess.err("Linker plugin based LTO is not supported together with \
diff --git a/src/librustc/session/search_paths.rs b/src/librustc/session/search_paths.rs
index 85d64b1571266..a950258cefd0c 100644
--- a/src/librustc/session/search_paths.rs
+++ b/src/librustc/session/search_paths.rs
@@ -1,6 +1,6 @@
 use std::path::{Path, PathBuf};
-use session::{early_error, config};
-use session::filesearch::make_target_lib_path;
+use crate::session::{early_error, config};
+use crate::session::filesearch::make_target_lib_path;
 
 #[derive(Clone, Debug)]
 pub struct SearchPath {
diff --git a/src/librustc/traits/auto_trait.rs b/src/librustc/traits/auto_trait.rs
index 92004ece26d00..60a3777abf844 100644
--- a/src/librustc/traits/auto_trait.rs
+++ b/src/librustc/traits/auto_trait.rs
@@ -6,12 +6,12 @@ use super::*;
 use std::collections::hash_map::Entry;
 use std::collections::VecDeque;
 
-use infer::region_constraints::{Constraint, RegionConstraintData};
-use infer::InferCtxt;
+use crate::infer::region_constraints::{Constraint, RegionConstraintData};
+use crate::infer::InferCtxt;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 
-use ty::fold::TypeFolder;
-use ty::{Region, RegionVid};
+use crate::ty::fold::TypeFolder;
+use crate::ty::{Region, RegionVid};
 
 // FIXME(twk): this is obviously not nice to duplicate like that
 #[derive(Eq, PartialEq, Hash, Copy, Clone, Debug)]
@@ -57,7 +57,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
         AutoTraitFinder { tcx }
     }
 
-    /// Make a best effort to determine whether and under which conditions an auto trait is
+    /// Makes a best effort to determine whether and under which conditions an auto trait is
     /// implemented for a type. For example, if you have
     ///
     /// ```
@@ -202,7 +202,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                 full_env,
                 ty,
                 trait_did,
-                ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID),
+                ObligationCause::misc(DUMMY_SP, hir::DUMMY_HIR_ID),
             );
             fulfill.select_all_or_error(&infcx).unwrap_or_else(|e| {
                 panic!(
@@ -315,7 +315,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
             user_env.caller_bounds.iter().cloned().collect();
 
         let mut new_env = param_env.clone();
-        let dummy_cause = ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID);
+        let dummy_cause = ObligationCause::misc(DUMMY_SP, hir::DUMMY_HIR_ID);
 
         while let Some(pred) = predicates.pop_front() {
             infcx.clear_caches();
@@ -669,7 +669,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
         select: &mut SelectionContext<'c, 'd, 'cx>,
         only_projections: bool,
     ) -> bool {
-        let dummy_cause = ObligationCause::misc(DUMMY_SP, ast::DUMMY_NODE_ID);
+        let dummy_cause = ObligationCause::misc(DUMMY_SP, hir::DUMMY_HIR_ID);
 
         for (obligation, mut predicate) in nested
             .map(|o| (o.clone(), o.predicate.clone()))
@@ -771,7 +771,13 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                     }
                 }
                 &ty::Predicate::RegionOutlives(ref binder) => {
-                    let () = select.infcx().region_outlives_predicate(&dummy_cause, binder);
+                    if select
+                        .infcx()
+                        .region_outlives_predicate(&dummy_cause, binder)
+                        .is_err()
+                    {
+                        return false;
+                    }
                 }
                 &ty::Predicate::TypeOutlives(ref binder) => {
                     match (
diff --git a/src/librustc/traits/chalk_fulfill.rs b/src/librustc/traits/chalk_fulfill.rs
index df4e08e0eb5f3..d9eb6d8157dfb 100644
--- a/src/librustc/traits/chalk_fulfill.rs
+++ b/src/librustc/traits/chalk_fulfill.rs
@@ -1,4 +1,4 @@
-use traits::{
+use crate::traits::{
     Environment,
     InEnvironment,
     TraitEngine,
@@ -8,10 +8,10 @@ use traits::{
     FulfillmentErrorCode,
     SelectionError,
 };
-use traits::query::NoSolution;
-use infer::InferCtxt;
-use infer::canonical::{Canonical, OriginalQueryValues};
-use ty::{self, Ty};
+use crate::traits::query::NoSolution;
+use crate::infer::InferCtxt;
+use crate::infer::canonical::{Canonical, OriginalQueryValues};
+use crate::ty::{self, Ty};
 use rustc_data_structures::fx::FxHashSet;
 
 pub type CanonicalGoal<'tcx> = Canonical<'tcx, InEnvironment<'tcx, ty::Predicate<'tcx>>>;
diff --git a/src/librustc/traits/codegen/mod.rs b/src/librustc/traits/codegen/mod.rs
index 94d56c2cbfc88..d6b7b3b99cacd 100644
--- a/src/librustc/traits/codegen/mod.rs
+++ b/src/librustc/traits/codegen/mod.rs
@@ -3,19 +3,19 @@
 // seems likely that they should eventually be merged into more
 // general routines.
 
-use dep_graph::{DepKind, DepTrackingMapConfig};
+use crate::dep_graph::{DepKind, DepTrackingMapConfig};
 use std::marker::PhantomData;
 use syntax_pos::DUMMY_SP;
-use infer::InferCtxt;
+use crate::infer::InferCtxt;
 use syntax_pos::Span;
-use traits::{FulfillmentContext, Obligation, ObligationCause, SelectionContext,
+use crate::traits::{FulfillmentContext, Obligation, ObligationCause, SelectionContext,
              TraitEngine, Vtable};
-use ty::{self, Ty, TyCtxt};
-use ty::subst::{Subst, Substs};
-use ty::fold::TypeFoldable;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::fold::TypeFoldable;
 
-/// Attempts to resolve an obligation to a vtable.. The result is
-/// a shallow vtable resolution -- meaning that we do not
+/// Attempts to resolve an obligation to a vtable. The result is
+/// a shallow vtable resolution, meaning that we do not
 /// (necessarily) resolve all nested obligations on the impl. Note
 /// that type check should guarantee to us that all nested
 /// obligations *could be* resolved if we wanted to.
diff --git a/src/librustc/traits/coherence.rs b/src/librustc/traits/coherence.rs
index 4c7049c366207..35d8e2beef557 100644
--- a/src/librustc/traits/coherence.rs
+++ b/src/librustc/traits/coherence.rs
@@ -1,20 +1,20 @@
-//! See rustc guide chapters on [trait-resolution] and [trait-specialization] for more info on how
+//! See Rustc Guide chapters on [trait-resolution] and [trait-specialization] for more info on how
 //! this works.
 //!
 //! [trait-resolution]: https://rust-lang.github.io/rustc-guide/traits/resolution.html
 //! [trait-specialization]: https://rust-lang.github.io/rustc-guide/traits/specialization.html
 
-use infer::CombinedSnapshot;
-use hir::def_id::{DefId, LOCAL_CRATE};
+use crate::infer::CombinedSnapshot;
+use crate::hir::def_id::{DefId, LOCAL_CRATE};
 use syntax_pos::DUMMY_SP;
-use traits::{self, Normalized, SelectionContext, Obligation, ObligationCause};
-use traits::IntercrateMode;
-use traits::select::IntercrateAmbiguityCause;
-use ty::{self, Ty, TyCtxt};
-use ty::fold::TypeFoldable;
-use ty::subst::Subst;
+use crate::traits::{self, Normalized, SelectionContext, Obligation, ObligationCause};
+use crate::traits::IntercrateMode;
+use crate::traits::select::IntercrateAmbiguityCause;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::fold::TypeFoldable;
+use crate::ty::subst::Subst;
 
-use infer::{InferOk};
+use crate::infer::{InferOk};
 
 /// Whether we do the orphan check relative to this crate or
 /// to some remote crate.
@@ -34,12 +34,12 @@ pub struct OverlapResult<'tcx> {
     pub impl_header: ty::ImplHeader<'tcx>,
     pub intercrate_ambiguity_causes: Vec<IntercrateAmbiguityCause>,
 
-    /// True if the overlap might've been permitted before the shift
+    /// `true` if the overlap might've been permitted before the shift
     /// to universes.
     pub involves_placeholder: bool,
 }
 
-pub fn add_placeholder_note(err: &mut ::errors::DiagnosticBuilder<'_>) {
+pub fn add_placeholder_note(err: &mut errors::DiagnosticBuilder<'_>) {
     err.note(&format!(
         "this behavior recently changed as a result of a bug fix; \
          see rust-lang/rust#56105 for details"
@@ -111,7 +111,7 @@ fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, '
 }
 
 /// Can both impl `a` and impl `b` be satisfied by a common type (including
-/// `where` clauses)? If so, returns an `ImplHeader` that unifies the two impls.
+/// where-clauses)? If so, returns an `ImplHeader` that unifies the two impls.
 fn overlap<'cx, 'gcx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
     a_def_id: DefId,
@@ -242,7 +242,7 @@ pub enum OrphanCheckErr<'tcx> {
 }
 
 /// Checks the coherence orphan rules. `impl_def_id` should be the
-/// def-id of a trait impl. To pass, either the trait must be local, or else
+/// `DefId` of a trait impl. To pass, either the trait must be local, or else
 /// two conditions must be satisfied:
 ///
 /// 1. All type parameters in `Self` must be "covered" by some local type constructor.
@@ -268,7 +268,7 @@ pub fn orphan_check<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
     orphan_check_trait_ref(tcx, trait_ref, InCrate::Local)
 }
 
-/// Check whether a trait-ref is potentially implementable by a crate.
+/// Checks whether a trait-ref is potentially implementable by a crate.
 ///
 /// The current rule is that a trait-ref orphan checks in a crate C:
 ///
diff --git a/src/librustc/traits/engine.rs b/src/librustc/traits/engine.rs
index c759a9ddf2ce6..2f019d823ff5d 100644
--- a/src/librustc/traits/engine.rs
+++ b/src/librustc/traits/engine.rs
@@ -1,7 +1,7 @@
-use infer::InferCtxt;
-use ty::{self, Ty, TyCtxt, ToPredicate};
-use traits::Obligation;
-use hir::def_id::DefId;
+use crate::infer::InferCtxt;
+use crate::ty::{self, Ty, TyCtxt, ToPredicate};
+use crate::traits::Obligation;
+use crate::hir::def_id::DefId;
 
 use super::{ChalkFulfillmentContext, FulfillmentContext, FulfillmentError};
 use super::{ObligationCause, PredicateObligation};
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 367a7eacdfcaf..3eb49092fed1d 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -17,24 +17,24 @@ use super::{
     Overflow,
 };
 
+use crate::hir;
+use crate::hir::Node;
+use crate::hir::def_id::DefId;
+use crate::infer::{self, InferCtxt};
+use crate::infer::type_variable::TypeVariableOrigin;
+use crate::session::DiagnosticMessageId;
+use crate::ty::{self, AdtKind, ToPredicate, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable};
+use crate::ty::GenericParamDefKind;
+use crate::ty::error::ExpectedFound;
+use crate::ty::fast_reject;
+use crate::ty::fold::TypeFolder;
+use crate::ty::subst::Subst;
+use crate::ty::SubtypePredicate;
+use crate::util::nodemap::{FxHashMap, FxHashSet};
+
 use errors::{Applicability, DiagnosticBuilder};
-use hir;
-use hir::Node;
-use hir::def_id::DefId;
-use infer::{self, InferCtxt};
-use infer::type_variable::TypeVariableOrigin;
 use std::fmt;
 use syntax::ast;
-use session::DiagnosticMessageId;
-use ty::{self, AdtKind, ToPredicate, ToPolyTraitRef, Ty, TyCtxt, TypeFoldable};
-use ty::GenericParamDefKind;
-use ty::error::ExpectedFound;
-use ty::fast_reject;
-use ty::fold::TypeFolder;
-use ty::subst::Subst;
-use ty::SubtypePredicate;
-use util::nodemap::{FxHashMap, FxHashSet};
-
 use syntax_pos::{DUMMY_SP, Span, ExpnInfo, ExpnFormat};
 
 impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
@@ -471,7 +471,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 
     fn report_similar_impl_candidates(&self,
-                                      mut impl_candidates: Vec<ty::TraitRef<'tcx>>,
+                                      impl_candidates: Vec<ty::TraitRef<'tcx>>,
                                       err: &mut DiagnosticBuilder<'_>)
     {
         if impl_candidates.is_empty() {
@@ -497,14 +497,18 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         });
 
         // Sort impl candidates so that ordering is consistent for UI tests.
-        let normalized_impl_candidates = &mut impl_candidates[0..end]
+        let mut normalized_impl_candidates = impl_candidates
             .iter()
             .map(normalize)
             .collect::<Vec<String>>();
+
+        // Sort before taking the `..end` range,
+        // because the ordering of `impl_candidates` may not be deterministic:
+        // https://github.com/rust-lang/rust/pull/57475#issuecomment-455519507
         normalized_impl_candidates.sort();
 
         err.help(&format!("the following implementations were found:{}{}",
-                          normalized_impl_candidates.join(""),
+                          normalized_impl_candidates[..end].join(""),
                           if len > 5 {
                               format!("\nand {} others", len - 4)
                           } else {
@@ -579,7 +583,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     }
 
 
-    /// Get the parent trait chain start
+    /// Gets the parent trait chain start
     fn get_parent_trait_ref(&self, code: &ObligationCauseCode<'tcx>) -> Option<String> {
         match code {
             &ObligationCauseCode::BuiltinDerivedObligation(ref data) => {
@@ -726,9 +730,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                     }
 
                     ty::Predicate::RegionOutlives(ref predicate) => {
-                        // These errors should show up as region
-                        // inference failures.
-                        panic!("region outlives {:?} failed", predicate);
+                        let predicate = self.resolve_type_vars_if_possible(predicate);
+                        let err = self.region_outlives_predicate(&obligation.cause,
+                                                                 &predicate).err().unwrap();
+                        struct_span_err!(
+                            self.tcx.sess, span, E0279,
+                            "the requirement `{}` is not satisfied (`{}`)",
+                            predicate, err,
+                        )
                     }
 
                     ty::Predicate::Projection(..) | ty::Predicate::TypeOutlives(..) => {
@@ -900,7 +909,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                 if let Some(ref expr) = local.init {
                     if let hir::ExprKind::Index(_, _) = expr.node {
                         if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(expr.span) {
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 expr.span,
                                 "consider borrowing here",
                                 format!("&{}", snippet),
@@ -948,7 +957,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                         let format_str = format!("consider removing {} leading `&`-references",
                                                  remove_refs);
 
-                        err.span_suggestion_short_with_applicability(
+                        err.span_suggestion_short(
                             sp, &format_str, String::new(), Applicability::MachineApplicable
                         );
                         break;
@@ -1020,7 +1029,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             Node::Variant(&hir::Variant {
                 span,
                 node: hir::VariantKind {
-                    data: hir::VariantData::Tuple(ref fields, _),
+                    data: hir::VariantData::Tuple(ref fields, ..),
                     ..
                 },
                 ..
@@ -1031,7 +1040,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                  ).collect::<Vec<_>>())
             }
             Node::StructCtor(ref variant_data) => {
-                (self.tcx.sess.source_map().def_span(self.tcx.hir().span(variant_data.id())),
+                (self.tcx.sess.source_map().def_span(
+                    self.tcx.hir().span_by_hir_id(variant_data.hir_id())),
                  vec![ArgKind::empty(); variant_data.fields().len()])
             }
             _ => panic!("non-FnLike node found: {:?}", node),
@@ -1105,7 +1115,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             // For example, if `expected_args_length` is 2, suggest `|_, _|`.
             if found_args.is_empty() && is_closure {
                 let underscores = vec!["_"; expected_args.len()].join(", ");
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     pipe_span,
                     &format!(
                         "consider changing the closure to take and ignore the expected argument{}",
@@ -1126,11 +1136,12 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                         .map(|(name, _)| name.to_owned())
                         .collect::<Vec<String>>()
                         .join(", ");
-                    err.span_suggestion_with_applicability(found_span,
-                                                           "change the closure to take multiple \
-                                                            arguments instead of a single tuple",
-                                                           format!("|{}|", sugg),
-                                                           Applicability::MachineApplicable);
+                    err.span_suggestion(
+                        found_span,
+                        "change the closure to take multiple arguments instead of a single tuple",
+                        format!("|{}|", sugg),
+                        Applicability::MachineApplicable,
+                    );
                 }
             }
             if let &[ArgKind::Tuple(_, ref fields)] = &expected_args[..] {
@@ -1158,12 +1169,11 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                             String::new()
                         },
                     );
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         found_span,
-                        "change the closure to accept a tuple instead of \
-                         individual arguments",
+                        "change the closure to accept a tuple instead of individual arguments",
                         sugg,
-                        Applicability::MachineApplicable
+                        Applicability::MachineApplicable,
                     );
                 }
             }
@@ -1371,7 +1381,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Returns whether the trait predicate may apply for *some* assignment
+    /// Returns `true` if the trait predicate may apply for *some* assignment
     /// to the type parameters.
     fn predicate_can_apply(&self,
                            param_env: ty::ParamEnv<'tcx>,
diff --git a/src/librustc/traits/fulfill.rs b/src/librustc/traits/fulfill.rs
index 2e00d4d4b7c3b..7648bde1d3c87 100644
--- a/src/librustc/traits/fulfill.rs
+++ b/src/librustc/traits/fulfill.rs
@@ -1,7 +1,7 @@
-use infer::InferCtxt;
-use mir::interpret::{GlobalId, ErrorHandled};
-use ty::{self, Ty, TypeFoldable, ToPolyTraitRef};
-use ty::error::ExpectedFound;
+use crate::infer::InferCtxt;
+use crate::mir::interpret::{GlobalId, ErrorHandled};
+use crate::ty::{self, Ty, TypeFoldable, ToPolyTraitRef};
+use crate::ty::error::ExpectedFound;
 use rustc_data_structures::obligation_forest::{DoCompleted, Error, ForestObligation};
 use rustc_data_structures::obligation_forest::{ObligationForest, ObligationProcessor};
 use rustc_data_structures::obligation_forest::{ProcessResult};
@@ -23,7 +23,7 @@ impl<'tcx> ForestObligation for PendingPredicateObligation<'tcx> {
     fn as_predicate(&self) -> &Self::Predicate { &self.obligation.predicate }
 }
 
-/// The fulfillment context is used to drive trait resolution.  It
+/// The fulfillment context is used to drive trait resolution. It
 /// consists of a list of obligations that must be (eventually)
 /// satisfied. The job is to track which are satisfied, which yielded
 /// errors, and which are still pending. At any point, users can call
@@ -140,7 +140,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     /// creating a fresh type variable `$0` as well as a projection
     /// predicate `<SomeType as SomeTrait>::X == $0`. When the
     /// inference engine runs, it will attempt to find an impl of
-    /// `SomeTrait` or a where clause that lets us unify `$0` with
+    /// `SomeTrait` or a where-clause that lets us unify `$0` with
     /// something concrete. If this fails, we'll unify `$0` with
     /// `projection_ty` again.
     fn normalize_projection_type<'a, 'gcx>(&mut self,
@@ -331,8 +331,10 @@ impl<'a, 'b, 'gcx, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'gcx,
             }
 
             ty::Predicate::RegionOutlives(ref binder) => {
-                let () = self.selcx.infcx().region_outlives_predicate(&obligation.cause, binder);
-                ProcessResult::Changed(vec![])
+                match self.selcx.infcx().region_outlives_predicate(&obligation.cause, binder) {
+                    Ok(()) => ProcessResult::Changed(vec![]),
+                    Err(_) => ProcessResult::Error(CodeSelectionError(Unimplemented)),
+                }
             }
 
             ty::Predicate::TypeOutlives(ref binder) => {
@@ -509,7 +511,7 @@ impl<'a, 'b, 'gcx, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'gcx,
     }
 }
 
-/// Return the set of type variables contained in a trait ref
+/// Returns the set of type variables contained in a trait ref
 fn trait_ref_type_vars<'a, 'gcx, 'tcx>(selcx: &mut SelectionContext<'a, 'gcx, 'tcx>,
                                        t: ty::PolyTraitRef<'tcx>) -> Vec<Ty<'tcx>>
 {
diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs
index 68383bef37a6a..99d1e32d52398 100644
--- a/src/librustc/traits/mod.rs
+++ b/src/librustc/traits/mod.rs
@@ -20,20 +20,20 @@ mod util;
 pub mod query;
 
 use chalk_engine;
-use hir;
-use hir::def_id::DefId;
-use infer::{InferCtxt, SuppressRegionErrors};
-use infer::outlives::env::OutlivesEnvironment;
-use middle::region;
-use mir::interpret::ErrorHandled;
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::infer::{InferCtxt, SuppressRegionErrors};
+use crate::infer::outlives::env::OutlivesEnvironment;
+use crate::middle::region;
+use crate::mir::interpret::ErrorHandled;
 use rustc_data_structures::sync::Lrc;
 use syntax::ast;
 use syntax_pos::{Span, DUMMY_SP};
-use ty::subst::Substs;
-use ty::{self, AdtKind, List, Ty, TyCtxt, GenericParamDefKind, ToPredicate};
-use ty::error::{ExpectedFound, TypeError};
-use ty::fold::{TypeFolder, TypeFoldable, TypeVisitor};
-use util::common::ErrorReported;
+use crate::ty::subst::Substs;
+use crate::ty::{self, AdtKind, List, Ty, TyCtxt, GenericParamDefKind, ToPredicate};
+use crate::ty::error::{ExpectedFound, TypeError};
+use crate::ty::fold::{TypeFolder, TypeFoldable, TypeVisitor};
+use crate::util::common::ErrorReported;
 
 use std::fmt::Debug;
 use std::rc::Rc;
@@ -73,14 +73,14 @@ pub use self::FulfillmentErrorCode::*;
 pub use self::SelectionError::*;
 pub use self::Vtable::*;
 
-// Whether to enable bug compatibility with issue #43355
+/// Whether to enable bug compatibility with issue #43355.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub enum IntercrateMode {
     Issue43355,
     Fixed
 }
 
-// The mode that trait queries run in
+/// The mode that trait queries run in.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub enum TraitQueryMode {
     // Standard/un-canonicalized queries get accurate
@@ -93,46 +93,46 @@ pub enum TraitQueryMode {
     Canonical,
 }
 
-/// An `Obligation` represents some trait reference (e.g., `int:Eq`) for
-/// which the vtable must be found.  The process of finding a vtable is
+/// An `Obligation` represents some trait reference (e.g., `int: Eq`) for
+/// which the vtable must be found. The process of finding a vtable is
 /// called "resolving" the `Obligation`. This process consists of
 /// either identifying an `impl` (e.g., `impl Eq for int`) that
 /// provides the required vtable, or else finding a bound that is in
 /// scope. The eventual result is usually a `Selection` (defined below).
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub struct Obligation<'tcx, T> {
-    /// Why do we have to prove this thing?
+    /// The reason we have to prove this thing.
     pub cause: ObligationCause<'tcx>,
 
-    /// In which environment should we prove this thing?
+    /// The environment in which we should prove this thing.
     pub param_env: ty::ParamEnv<'tcx>,
 
-    /// What are we trying to prove?
+    /// The thing we are trying to prove.
     pub predicate: T,
 
     /// If we started proving this as a result of trying to prove
     /// something else, track the total depth to ensure termination.
     /// If this goes over a certain threshold, we abort compilation --
     /// in such cases, we can not say whether or not the predicate
-    /// holds for certain. Stupid halting problem. Such a drag.
+    /// holds for certain. Stupid halting problem; such a drag.
     pub recursion_depth: usize,
 }
 
 pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>;
 pub type TraitObligation<'tcx> = Obligation<'tcx, ty::PolyTraitPredicate<'tcx>>;
 
-/// Why did we incur this obligation? Used for error reporting.
+/// The reason why we incurred this obligation; used for error reporting.
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct ObligationCause<'tcx> {
     pub span: Span,
 
-    // The id of the fn body that triggered this obligation. This is
-    // used for region obligations to determine the precise
-    // environment in which the region obligation should be evaluated
-    // (in particular, closures can add new assumptions). See the
-    // field `region_obligations` of the `FulfillmentContext` for more
-    // information.
-    pub body_id: ast::NodeId,
+    /// The ID of the fn body that triggered this obligation. This is
+    /// used for region obligations to determine the precise
+    /// environment in which the region obligation should be evaluated
+    /// (in particular, closures can add new assumptions). See the
+    /// field `region_obligations` of the `FulfillmentContext` for more
+    /// information.
+    pub body_id: hir::HirId,
 
     pub code: ObligationCauseCode<'tcx>
 }
@@ -145,6 +145,7 @@ impl<'tcx> ObligationCause<'tcx> {
             ObligationCauseCode::StartFunctionType => {
                 tcx.sess.source_map().def_span(self.span)
             }
+            ObligationCauseCode::MatchExpressionArm { arm_span, .. } => arm_span,
             _ => self.span,
         }
     }
@@ -152,20 +153,20 @@ impl<'tcx> ObligationCause<'tcx> {
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ObligationCauseCode<'tcx> {
-    /// Not well classified or should be obvious from span.
+    /// Not well classified or should be obvious from the span.
     MiscObligation,
 
-    /// A slice or array is WF only if `T: Sized`
+    /// A slice or array is WF only if `T: Sized`.
     SliceOrArrayElem,
 
-    /// A tuple is WF only if its middle elements are Sized
+    /// A tuple is WF only if its middle elements are `Sized`.
     TupleElem,
 
-    /// This is the trait reference from the given projection
+    /// This is the trait reference from the given projection.
     ProjectionWf(ty::ProjectionTy<'tcx>),
 
-    /// In an impl of trait X for type Y, type Y must
-    /// also implement all supertraits of X.
+    /// In an impl of trait `X` for type `Y`, type `Y` must
+    /// also implement all supertraits of `X`.
     ItemObligation(DefId),
 
     /// A type like `&'a T` is WF only if `T: 'a`.
@@ -223,6 +224,8 @@ pub enum ObligationCauseCode<'tcx> {
     MatchExpressionArm {
         arm_span: Span,
         source: hir::MatchSource,
+        prior_arms: Vec<Span>,
+        last_ty: Ty<'tcx>,
     },
 
     /// Computing common supertype in the pattern guard for the arms of a match expression
@@ -271,7 +274,7 @@ pub struct DerivedObligationCause<'tcx> {
     /// directly.
     parent_trait_ref: ty::PolyTraitRef<'tcx>,
 
-    /// The parent trait had this cause
+    /// The parent trait had this cause.
     parent_code: Rc<ObligationCauseCode<'tcx>>
 }
 
@@ -280,14 +283,14 @@ pub type PredicateObligations<'tcx> = Vec<PredicateObligation<'tcx>>;
 pub type TraitObligations<'tcx> = Vec<TraitObligation<'tcx>>;
 
 /// The following types:
-/// * `WhereClause`
-/// * `WellFormed`
-/// * `FromEnv`
-/// * `DomainGoal`
-/// * `Goal`
-/// * `Clause`
-/// * `Environment`
-/// * `InEnvironment`
+/// * `WhereClause`,
+/// * `WellFormed`,
+/// * `FromEnv`,
+/// * `DomainGoal`,
+/// * `Goal`,
+/// * `Clause`,
+/// * `Environment`,
+/// * `InEnvironment`,
 /// are used for representing the trait system in the form of
 /// logic programming clauses. They are part of the interface
 /// for the chalk SLG solver.
@@ -399,10 +402,10 @@ pub type Clauses<'tcx> = &'tcx List<Clause<'tcx>>;
 /// with the goal to solve and proceeds from there).
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
 pub struct ProgramClause<'tcx> {
-    /// This goal will be considered true...
+    /// This goal will be considered true ...
     pub goal: DomainGoal<'tcx>,
 
-    /// ...if we can prove these hypotheses (there may be no hypotheses at all):
+    /// ... if we can prove these hypotheses (there may be no hypotheses at all):
     pub hypotheses: Goals<'tcx>,
 
     /// Useful for filtering clauses.
@@ -485,7 +488,6 @@ pub type SelectionResult<'tcx, T> = Result<Option<T>, SelectionError<'tcx>>;
 /// For example, the vtable may be tied to a specific impl (case A),
 /// or it may be relative to some bound that is in scope (case B).
 ///
-///
 /// ```
 /// impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1
 /// impl<T:Clone> Clone<T> for Box<T> { ... }    // Impl_2
@@ -517,7 +519,7 @@ pub enum Vtable<'tcx, N> {
     /// Vtable identifying a particular impl.
     VtableImpl(VtableImplData<'tcx, N>),
 
-    /// Vtable for auto trait implementations
+    /// Vtable for auto trait implementations.
     /// This carries the information and nested obligations with regards
     /// to an auto implementation for a trait `Trait`. The nested obligations
     /// ensure the trait implementation holds for all the constituent types.
@@ -529,18 +531,18 @@ pub enum Vtable<'tcx, N> {
     /// any).
     VtableParam(Vec<N>),
 
-    /// Virtual calls through an object
+    /// Virtual calls through an object.
     VtableObject(VtableObjectData<'tcx, N>),
 
     /// Successful resolution for a builtin trait.
     VtableBuiltin(VtableBuiltinData<N>),
 
-    /// Vtable automatically generated for a closure. The def ID is the ID
+    /// Vtable automatically generated for a closure. The `DefId` is the ID
     /// of the closure expression. This is a `VtableImpl` in spirit, but the
     /// impl is generated by the compiler and does not appear in the source.
     VtableClosure(VtableClosureData<'tcx, N>),
 
-    /// Same as above, but for a fn pointer type with the given signature.
+    /// Same as above, but for a function pointer type with the given signature.
     VtableFnPointer(VtableFnPointerData<'tcx, N>),
 
     /// Vtable automatically generated for a generator.
@@ -655,7 +657,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'gcx, 'tcx>(
     };
     let obligation = Obligation {
         param_env,
-        cause: ObligationCause::misc(span, ast::DUMMY_NODE_ID),
+        cause: ObligationCause::misc(span, hir::DUMMY_HIR_ID),
         recursion_depth: 0,
         predicate: trait_ref.to_predicate(),
     };
@@ -678,7 +680,7 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'gcx, 'tcx>(
         // We can use a dummy node-id here because we won't pay any mind
         // to region obligations that arise (there shouldn't really be any
         // anyhow).
-        let cause = ObligationCause::misc(span, ast::DUMMY_NODE_ID);
+        let cause = ObligationCause::misc(span, hir::DUMMY_HIR_ID);
 
         fulfill_cx.register_bound(infcx, param_env, ty, def_id, cause);
 
@@ -1058,7 +1060,7 @@ impl<'tcx,O> Obligation<'tcx,O> {
     }
 
     pub fn misc(span: Span,
-                body_id: ast::NodeId,
+                body_id: hir::HirId,
                 param_env: ty::ParamEnv<'tcx>,
                 trait_ref: O)
                 -> Obligation<'tcx, O> {
@@ -1076,18 +1078,18 @@ impl<'tcx,O> Obligation<'tcx,O> {
 impl<'tcx> ObligationCause<'tcx> {
     #[inline]
     pub fn new(span: Span,
-               body_id: ast::NodeId,
+               body_id: hir::HirId,
                code: ObligationCauseCode<'tcx>)
                -> ObligationCause<'tcx> {
-        ObligationCause { span: span, body_id: body_id, code: code }
+        ObligationCause { span, body_id, code }
     }
 
-    pub fn misc(span: Span, body_id: ast::NodeId) -> ObligationCause<'tcx> {
-        ObligationCause { span: span, body_id: body_id, code: MiscObligation }
+    pub fn misc(span: Span, body_id: hir::HirId) -> ObligationCause<'tcx> {
+        ObligationCause { span, body_id, code: MiscObligation }
     }
 
     pub fn dummy() -> ObligationCause<'tcx> {
-        ObligationCause { span: DUMMY_SP, body_id: ast::CRATE_NODE_ID, code: MiscObligation }
+        ObligationCause { span: DUMMY_SP, body_id: hir::CRATE_HIR_ID, code: MiscObligation }
     }
 }
 
diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs
index c37dc2a855ed0..b31aa5998f365 100644
--- a/src/librustc/traits/object_safety.rs
+++ b/src/librustc/traits/object_safety.rs
@@ -6,15 +6,15 @@
 //!   - have a suitable receiver from which we can extract a vtable and coerce to a "thin" version
 //!     that doesn't contain the vtable;
 //!   - not reference the erased type `Self` except for in this receiver;
-//!   - not have generic type parameters
+//!   - not have generic type parameters.
 
 use super::elaborate_predicates;
 
-use hir::def_id::DefId;
-use lint;
-use traits::{self, Obligation, ObligationCause};
-use ty::{self, Ty, TyCtxt, TypeFoldable, Predicate, ToPredicate};
-use ty::subst::{Subst, Substs};
+use crate::hir::def_id::DefId;
+use crate::lint;
+use crate::traits::{self, Obligation, ObligationCause};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable, Predicate, ToPredicate};
+use crate::ty::subst::{Subst, Substs};
 use std::borrow::Cow;
 use std::iter::{self};
 use syntax::ast::{self, Name};
@@ -22,17 +22,17 @@ use syntax_pos::Span;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum ObjectSafetyViolation {
-    /// Self : Sized declared on the trait
+    /// `Self: Sized` declared on the trait.
     SizedSelf,
 
     /// Supertrait reference references `Self` an in illegal location
-    /// (e.g., `trait Foo : Bar<Self>`)
+    /// (e.g., `trait Foo : Bar<Self>`).
     SupertraitSelf,
 
-    /// Method has something illegal
+    /// Method has something illegal.
     Method(ast::Name, MethodViolationCode),
 
-    /// Associated const
+    /// Associated const.
     AssociatedConst(ast::Name),
 }
 
@@ -84,7 +84,7 @@ pub enum MethodViolationCode {
 impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
 
     /// Returns the object safety violations that affect
-    /// astconv - currently, Self in supertraits. This is needed
+    /// astconv -- currently, `Self` in supertraits. This is needed
     /// because `object_safety_violations` can't be used during
     /// type collection.
     pub fn astconv_object_safety_violations(self, trait_def_id: DefId)
@@ -341,7 +341,7 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
             } else {
                 // sanity check to make sure the receiver actually has the layout of a pointer
 
-                use ty::layout::Abi;
+                use crate::ty::layout::Abi;
 
                 let param_env = self.param_env(method.def_id);
 
@@ -399,8 +399,8 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         None
     }
 
-    /// performs a type substitution to produce the version of receiver_ty when `Self = self_ty`
-    /// e.g., for receiver_ty = `Rc<Self>` and self_ty = `Foo`, returns `Rc<Foo>`
+    /// Performs a type substitution to produce the version of receiver_ty when `Self = self_ty`
+    /// e.g., for receiver_ty = `Rc<Self>` and self_ty = `Foo`, returns `Rc<Foo>`.
     fn receiver_for_self_ty(
         self, receiver_ty: Ty<'tcx>, self_ty: Ty<'tcx>, method_def_id: DefId
     ) -> Ty<'tcx> {
@@ -419,9 +419,9 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         result
     }
 
-    /// creates the object type for the current trait. For example,
+    /// Creates the object type for the current trait. For example,
     /// if the current trait is `Deref`, then this will be
-    /// `dyn Deref<Target=Self::Target> + 'static`
+    /// `dyn Deref<Target = Self::Target> + 'static`.
     fn object_ty_for_trait(self, trait_def_id: DefId, lifetime: ty::Region<'tcx>) -> Ty<'tcx> {
         debug!("object_ty_for_trait: trait_def_id={:?}", trait_def_id);
 
@@ -470,25 +470,27 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         object_ty
     }
 
-    /// checks the method's receiver (the `self` argument) can be dispatched on when `Self` is a
+    /// Checks the method's receiver (the `self` argument) can be dispatched on when `Self` is a
     /// trait object. We require that `DispatchableFromDyn` be implemented for the receiver type
     /// in the following way:
-    /// - let `Receiver` be the type of the `self` argument, i.e `Self`, `&Self`, `Rc<Self>`
+    /// - let `Receiver` be the type of the `self` argument, i.e `Self`, `&Self`, `Rc<Self>`,
     /// - require the following bound:
     ///
-    ///        Receiver[Self => T]: DispatchFromDyn<Receiver[Self => dyn Trait]>
+    ///   ```
+    ///   Receiver[Self => T]: DispatchFromDyn<Receiver[Self => dyn Trait]>
+    ///   ```
     ///
-    ///    where `Foo[X => Y]` means "the same type as `Foo`, but with `X` replaced with `Y`"
+    ///   where `Foo[X => Y]` means "the same type as `Foo`, but with `X` replaced with `Y`"
     ///   (substitution notation).
     ///
-    /// some examples of receiver types and their required obligation
-    /// - `&'a mut self` requires `&'a mut Self: DispatchFromDyn<&'a mut dyn Trait>`
-    /// - `self: Rc<Self>` requires `Rc<Self>: DispatchFromDyn<Rc<dyn Trait>>`
-    /// - `self: Pin<Box<Self>>` requires `Pin<Box<Self>>: DispatchFromDyn<Pin<Box<dyn Trait>>>`
+    /// Some examples of receiver types and their required obligation:
+    /// - `&'a mut self` requires `&'a mut Self: DispatchFromDyn<&'a mut dyn Trait>`,
+    /// - `self: Rc<Self>` requires `Rc<Self>: DispatchFromDyn<Rc<dyn Trait>>`,
+    /// - `self: Pin<Box<Self>>` requires `Pin<Box<Self>>: DispatchFromDyn<Pin<Box<dyn Trait>>>`.
     ///
     /// The only case where the receiver is not dispatchable, but is still a valid receiver
     /// type (just not object-safe), is when there is more than one level of pointer indirection.
-    /// e.g., `self: &&Self`, `self: &Rc<Self>`, `self: Box<Box<Self>>`. In these cases, there
+    /// E.g., `self: &&Self`, `self: &Rc<Self>`, `self: Box<Box<Self>>`. In these cases, there
     /// is no way, or at least no inexpensive way, to coerce the receiver from the version where
     /// `Self = dyn Trait` to the version where `Self = T`, where `T` is the unknown erased type
     /// contained by the trait object, because the object that needs to be coerced is behind
diff --git a/src/librustc/traits/on_unimplemented.rs b/src/librustc/traits/on_unimplemented.rs
index 3ec901f50e4cc..f61c32614cc93 100644
--- a/src/librustc/traits/on_unimplemented.rs
+++ b/src/librustc/traits/on_unimplemented.rs
@@ -1,9 +1,9 @@
 use fmt_macros::{Parser, Piece, Position};
 
-use hir::def_id::DefId;
-use ty::{self, TyCtxt, GenericParamDefKind};
-use util::common::ErrorReported;
-use util::nodemap::FxHashMap;
+use crate::hir::def_id::DefId;
+use crate::ty::{self, TyCtxt, GenericParamDefKind};
+use crate::util::common::ErrorReported;
+use crate::util::nodemap::FxHashMap;
 
 use syntax::ast::{MetaItem, NestedMetaItem};
 use syntax::attr;
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs
index bec45046cb93e..05141c9daf1d4 100644
--- a/src/librustc/traits/project.rs
+++ b/src/librustc/traits/project.rs
@@ -12,16 +12,16 @@ use super::SelectionError;
 use super::{VtableImplData, VtableClosureData, VtableGeneratorData, VtableFnPointerData};
 use super::util;
 
-use hir::def_id::DefId;
-use infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
-use infer::type_variable::TypeVariableOrigin;
-use mir::interpret::{GlobalId};
+use crate::hir::def_id::DefId;
+use crate::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
+use crate::infer::type_variable::TypeVariableOrigin;
+use crate::mir::interpret::{GlobalId};
 use rustc_data_structures::snapshot_map::{Snapshot, SnapshotMap};
 use syntax::ast::Ident;
-use ty::subst::{Subst, Substs};
-use ty::{self, ToPredicate, ToPolyTraitRef, Ty, TyCtxt};
-use ty::fold::{TypeFoldable, TypeFolder};
-use util::common::FN_OUTPUT_NAME;
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::{self, ToPredicate, ToPolyTraitRef, Ty, TyCtxt};
+use crate::ty::fold::{TypeFoldable, TypeFolder};
+use crate::util::common::FN_OUTPUT_NAME;
 
 /// Depending on the stage of compilation, we want projection to be
 /// more or less conservative.
@@ -55,7 +55,7 @@ pub enum Reveal {
     /// Also, `impl Trait` is normalized to the concrete type,
     /// which has to be already collected by type-checking.
     ///
-    /// NOTE: As `impl Trait`'s concrete type should *never*
+    /// NOTE: as `impl Trait`'s concrete type should *never*
     /// be observable directly by the user, `Reveal::All`
     /// should not be used by checks which may expose
     /// type equality or type contents to the user.
@@ -191,12 +191,15 @@ pub fn poly_project_and_unify_type<'cx, 'gcx, 'tcx>(
            obligation);
 
     let infcx = selcx.infcx();
-    infcx.commit_if_ok(|_| {
-        let (placeholder_predicate, _) =
+    infcx.commit_if_ok(|snapshot| {
+        let (placeholder_predicate, placeholder_map) =
             infcx.replace_bound_vars_with_placeholders(&obligation.predicate);
 
         let placeholder_obligation = obligation.with(placeholder_predicate);
-        project_and_unify_type(selcx, &placeholder_obligation)
+        let result = project_and_unify_type(selcx, &placeholder_obligation)?;
+        infcx.leak_check(false, &placeholder_map, snapshot)
+            .map_err(|err| MismatchedProjectionTypes { err })?;
+        Ok(result)
     })
 }
 
@@ -408,7 +411,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for AssociatedTypeNormalizer<'a,
                         if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
                             let substs = tcx.lift_to_global(&substs).unwrap();
                             let evaluated = evaluated.subst(tcx, substs);
-                            return tcx.intern_lazy_const(ty::LazyConst::Evaluated(evaluated));
+                            return tcx.mk_lazy_const(ty::LazyConst::Evaluated(evaluated));
                         }
                     }
                 } else {
@@ -420,7 +423,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for AssociatedTypeNormalizer<'a,
                                 promoted: None
                             };
                             if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
-                                return tcx.intern_lazy_const(ty::LazyConst::Evaluated(evaluated));
+                                return tcx.mk_lazy_const(ty::LazyConst::Evaluated(evaluated));
                             }
                         }
                     }
@@ -751,9 +754,9 @@ fn prune_cache_value_obligations<'a, 'gcx, 'tcx>(infcx: &'a InferCtxt<'a, 'gcx,
 ///
 /// Concern #2. Even within the snapshot, if those original
 /// obligations are not yet proven, then we are able to do projections
-/// that may yet turn out to be wrong.  This *may* lead to some sort
+/// that may yet turn out to be wrong. This *may* lead to some sort
 /// of trouble, though we don't have a concrete example of how that
-/// can occur yet.  But it seems risky at best.
+/// can occur yet. But it seems risky at best.
 fn get_paranoid_cache_value_obligation<'a, 'gcx, 'tcx>(
     infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -786,7 +789,7 @@ fn get_paranoid_cache_value_obligation<'a, 'gcx, 'tcx>(
 /// cycles to arise, where you basically had a setup like `<MyType<$0>
 /// as Trait>::Foo == $0`. Here, normalizing `<MyType<$0> as
 /// Trait>::Foo> to `[type error]` would lead to an obligation of
-/// `<MyType<[type error]> as Trait>::Foo`.  We are supposed to report
+/// `<MyType<[type error]> as Trait>::Foo`. We are supposed to report
 /// an error for this obligation, but we legitimately should not,
 /// because it contains `[type error]`. Yuck! (See issue #29857 for
 /// one case where this arose.)
@@ -844,7 +847,7 @@ impl<'tcx> Progress<'tcx> {
     }
 }
 
-/// Compute the result of a projection type (if we can).
+/// Computes the result of a projection type (if we can).
 ///
 /// IMPORTANT:
 /// - `obligation` must be fully normalized
@@ -1427,9 +1430,8 @@ fn confirm_callable_candidate<'cx, 'gcx, 'tcx>(
 fn confirm_param_env_candidate<'cx, 'gcx, 'tcx>(
     selcx: &mut SelectionContext<'cx, 'gcx, 'tcx>,
     obligation: &ProjectionTyObligation<'tcx>,
-    poly_cache_entry: ty::PolyProjectionPredicate<'tcx>)
-    -> Progress<'tcx>
-{
+    poly_cache_entry: ty::PolyProjectionPredicate<'tcx>,
+) -> Progress<'tcx> {
     let infcx = selcx.infcx();
     let cause = &obligation.cause;
     let param_env = obligation.param_env;
@@ -1553,7 +1555,7 @@ fn assoc_ty_def<'cx, 'gcx, 'tcx>(
 // # Cache
 
 /// The projection cache. Unlike the standard caches, this can include
-/// infcx-dependent type variables - therefore, we have to roll the
+/// infcx-dependent type variables, therefore we have to roll the
 /// cache back each time we roll a snapshot back, to avoid assumptions
 /// on yet-unresolved inference variables. Types with placeholder
 /// regions also have to be removed when the respective snapshot ends.
@@ -1564,9 +1566,9 @@ fn assoc_ty_def<'cx, 'gcx, 'tcx>(
 /// (for the lifetime of the infcx).
 ///
 /// Entries in the projection cache might contain inference variables
-/// that will be resolved by obligations on the projection cache entry - e.g.
+/// that will be resolved by obligations on the projection cache entry (e.g.,
 /// when a type parameter in the associated type is constrained through
-/// an "RFC 447" projection on the impl.
+/// an "RFC 447" projection on the impl).
 ///
 /// When working with a fulfillment context, the derived obligations of each
 /// projection cache entry will be registered on the fulfillcx, so any users
@@ -1578,10 +1580,9 @@ fn assoc_ty_def<'cx, 'gcx, 'tcx>(
 /// If that is done, after evaluation the obligations, it is a good idea to
 /// call `ProjectionCache::complete` to make sure the obligations won't be
 /// re-evaluated and avoid an exponential worst-case.
-///
-/// FIXME: we probably also want some sort of cross-infcx cache here to
-/// reduce the amount of duplication. Let's see what we get with the Chalk
-/// reforms.
+//
+// FIXME: we probably also want some sort of cross-infcx cache here to
+// reduce the amount of duplication. Let's see what we get with the Chalk reforms.
 #[derive(Default)]
 pub struct ProjectionCache<'tcx> {
     map: SnapshotMap<ProjectionCacheKey<'tcx>, ProjectionCacheEntry<'tcx>>,
diff --git a/src/librustc/traits/query/dropck_outlives.rs b/src/librustc/traits/query/dropck_outlives.rs
index 1fd2172212d3c..e6f9c7ebe6fe4 100644
--- a/src/librustc/traits/query/dropck_outlives.rs
+++ b/src/librustc/traits/query/dropck_outlives.rs
@@ -1,10 +1,10 @@
-use infer::at::At;
-use infer::InferOk;
-use infer::canonical::OriginalQueryValues;
+use crate::infer::at::At;
+use crate::infer::InferOk;
+use crate::infer::canonical::OriginalQueryValues;
 use std::iter::FromIterator;
 use syntax::source_map::Span;
-use ty::subst::Kind;
-use ty::{self, Ty, TyCtxt};
+use crate::ty::subst::Kind;
+use crate::ty::{self, Ty, TyCtxt};
 
 impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
     /// Given a type `ty` of some value being dropped, computes a set
@@ -184,7 +184,7 @@ impl_stable_hash_for!(struct DtorckConstraint<'tcx> {
 /// outlive. This is similar but not *quite* the same as the
 /// `needs_drop` test in the compiler already -- that is, for every
 /// type T for which this function return true, needs-drop would
-/// return false. But the reverse does not hold: in particular,
+/// return `false`. But the reverse does not hold: in particular,
 /// `needs_drop` returns false for `PhantomData`, but it is not
 /// trivial for dropck-outlives.
 ///
diff --git a/src/librustc/traits/query/evaluate_obligation.rs b/src/librustc/traits/query/evaluate_obligation.rs
index fdae7d833734e..d5230f15c2565 100644
--- a/src/librustc/traits/query/evaluate_obligation.rs
+++ b/src/librustc/traits/query/evaluate_obligation.rs
@@ -1,6 +1,6 @@
-use infer::InferCtxt;
-use infer::canonical::OriginalQueryValues;
-use traits::{EvaluationResult, PredicateObligation, SelectionContext,
+use crate::infer::InferCtxt;
+use crate::infer::canonical::OriginalQueryValues;
+use crate::traits::{EvaluationResult, PredicateObligation, SelectionContext,
              TraitQueryMode, OverflowError};
 
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
diff --git a/src/librustc/traits/query/method_autoderef.rs b/src/librustc/traits/query/method_autoderef.rs
index b4984e1237857..6b9bdfd63f4d0 100644
--- a/src/librustc/traits/query/method_autoderef.rs
+++ b/src/librustc/traits/query/method_autoderef.rs
@@ -1,6 +1,6 @@
 use rustc_data_structures::sync::Lrc;
-use infer::canonical::{Canonical, QueryResponse};
-use ty::Ty;
+use crate::infer::canonical::{Canonical, QueryResponse};
+use crate::ty::Ty;
 
 #[derive(Debug)]
 pub struct CandidateStep<'tcx> {
diff --git a/src/librustc/traits/query/mod.rs b/src/librustc/traits/query/mod.rs
index 59f786025b224..112a1d0e09c94 100644
--- a/src/librustc/traits/query/mod.rs
+++ b/src/librustc/traits/query/mod.rs
@@ -5,9 +5,9 @@
 //! The providers for the queries defined here can be found in
 //! `librustc_traits`.
 
-use infer::canonical::Canonical;
-use ty::error::TypeError;
-use ty::{self, Ty};
+use crate::infer::canonical::Canonical;
+use crate::ty::error::TypeError;
+use crate::ty::{self, Ty};
 
 pub mod dropck_outlives;
 pub mod evaluate_obligation;
diff --git a/src/librustc/traits/query/normalize.rs b/src/librustc/traits/query/normalize.rs
index be05445cfc61a..224076ce17e72 100644
--- a/src/librustc/traits/query/normalize.rs
+++ b/src/librustc/traits/query/normalize.rs
@@ -2,15 +2,15 @@
 //! which folds deeply, invoking the underlying
 //! `normalize_projection_ty` query when it encounters projections.
 
-use infer::at::At;
-use infer::canonical::OriginalQueryValues;
-use infer::{InferCtxt, InferOk};
-use mir::interpret::GlobalId;
-use traits::project::Normalized;
-use traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
-use ty::fold::{TypeFoldable, TypeFolder};
-use ty::subst::{Subst, Substs};
-use ty::{self, Ty, TyCtxt};
+use crate::infer::at::At;
+use crate::infer::canonical::OriginalQueryValues;
+use crate::infer::{InferCtxt, InferOk};
+use crate::mir::interpret::GlobalId;
+use crate::traits::project::Normalized;
+use crate::traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
+use crate::ty::fold::{TypeFoldable, TypeFolder};
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::{self, Ty, TyCtxt};
 
 use super::NoSolution;
 
@@ -24,7 +24,7 @@ impl<'cx, 'gcx, 'tcx> At<'cx, 'gcx, 'tcx> {
     /// the normalized value along with various outlives relations (in
     /// the form of obligations that must be discharged).
     ///
-    /// NB. This will *eventually* be the main means of
+    /// N.B., this will *eventually* be the main means of
     /// normalizing, but for now should be used only when we actually
     /// know that normalization will succeed, since error reporting
     /// and other details are still "under development".
@@ -203,7 +203,7 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for QueryNormalizer<'cx, 'gcx, 'tcx
                         if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
                             let substs = tcx.lift_to_global(&substs).unwrap();
                             let evaluated = evaluated.subst(tcx, substs);
-                            return tcx.intern_lazy_const(ty::LazyConst::Evaluated(evaluated));
+                            return tcx.mk_lazy_const(ty::LazyConst::Evaluated(evaluated));
                         }
                     }
                 } else {
@@ -215,7 +215,7 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for QueryNormalizer<'cx, 'gcx, 'tcx
                                 promoted: None,
                             };
                             if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
-                                return tcx.intern_lazy_const(ty::LazyConst::Evaluated(evaluated));
+                                return tcx.mk_lazy_const(ty::LazyConst::Evaluated(evaluated));
                             }
                         }
                     }
diff --git a/src/librustc/traits/query/normalize_erasing_regions.rs b/src/librustc/traits/query/normalize_erasing_regions.rs
index e7034065bdf2e..0c1252680c1db 100644
--- a/src/librustc/traits/query/normalize_erasing_regions.rs
+++ b/src/librustc/traits/query/normalize_erasing_regions.rs
@@ -7,8 +7,8 @@
 //! `normalize_ty_after_erasing_regions` query for each type found
 //! within. (This underlying query is what is cached.)
 
-use ty::{self, Ty, TyCtxt};
-use ty::fold::{TypeFoldable, TypeFolder};
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::fold::{TypeFoldable, TypeFolder};
 
 impl<'cx, 'tcx> TyCtxt<'cx, 'tcx, 'tcx> {
     /// Erase the regions in `value` and then fully normalize all the
@@ -45,7 +45,7 @@ impl<'cx, 'tcx> TyCtxt<'cx, 'tcx, 'tcx> {
     /// a `T` (with regions erased). This is appropriate when the
     /// binder is being instantiated at the call site.
     ///
-    /// NB. Currently, higher-ranked type bounds inhibit
+    /// N.B., currently, higher-ranked type bounds inhibit
     /// normalization. Therefore, each time we erase them in
     /// codegen, we need to normalize the contents.
     pub fn normalize_erasing_late_bound_regions<T>(
diff --git a/src/librustc/traits/query/outlives_bounds.rs b/src/librustc/traits/query/outlives_bounds.rs
index 1134cb1b2f5d0..954de15905fb7 100644
--- a/src/librustc/traits/query/outlives_bounds.rs
+++ b/src/librustc/traits/query/outlives_bounds.rs
@@ -1,19 +1,19 @@
-use infer::InferCtxt;
-use infer::canonical::OriginalQueryValues;
-use syntax::ast;
+use crate::infer::InferCtxt;
+use crate::infer::canonical::OriginalQueryValues;
+use crate::hir;
 use syntax::source_map::Span;
-use traits::{FulfillmentContext, ObligationCause, TraitEngine, TraitEngineExt};
-use traits::query::NoSolution;
-use ty::{self, Ty, TyCtxt};
+use crate::traits::{FulfillmentContext, ObligationCause, TraitEngine, TraitEngineExt};
+use crate::traits::query::NoSolution;
+use crate::ty::{self, Ty, TyCtxt};
 
-use ich::StableHashingContext;
+use crate::ich::StableHashingContext;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
 use std::mem;
 
 /// Outlives bounds are relationships between generic parameters,
 /// whether they both be regions (`'a: 'b`) or whether types are
-/// involved (`T: 'a`).  These relationships can be extracted from the
+/// involved (`T: 'a`). These relationships can be extracted from the
 /// full set of predicates we understand or also from types (in which
 /// case they are called implied bounds). They are fed to the
 /// `OutlivesEnv` which in turn is supplied to the region checker and
@@ -66,7 +66,7 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for OutlivesBound<'tcx> {
 
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// Implied bounds are region relationships that we deduce
-    /// automatically.  The idea is that (e.g.) a caller must check that a
+    /// automatically. The idea is that (e.g.) a caller must check that a
     /// function's argument types are well-formed immediately before
     /// calling that fn, and hence the *callee* can assume that its
     /// argument types are well-formed. This may imply certain relationships
@@ -89,7 +89,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     pub fn implied_outlives_bounds(
         &self,
         param_env: ty::ParamEnv<'tcx>,
-        body_id: ast::NodeId,
+        body_id: hir::HirId,
         ty: Ty<'tcx>,
         span: Span,
     ) -> Vec<OutlivesBound<'tcx>> {
diff --git a/src/librustc/traits/query/type_op/ascribe_user_type.rs b/src/librustc/traits/query/type_op/ascribe_user_type.rs
index b2f30564de93a..d9f573eb7e291 100644
--- a/src/librustc/traits/query/type_op/ascribe_user_type.rs
+++ b/src/librustc/traits/query/type_op/ascribe_user_type.rs
@@ -1,28 +1,23 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::Fallible;
-use hir::def_id::DefId;
-use mir::ProjectionKind;
-use ty::{self, ParamEnvAnd, Ty, TyCtxt};
-use ty::subst::UserSubsts;
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::Fallible;
+use crate::hir::def_id::DefId;
+use crate::ty::{ParamEnvAnd, Ty, TyCtxt};
+use crate::ty::subst::UserSubsts;
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct AscribeUserType<'tcx> {
     pub mir_ty: Ty<'tcx>,
-    pub variance: ty::Variance,
     pub def_id: DefId,
     pub user_substs: UserSubsts<'tcx>,
-    pub projs: &'tcx ty::List<ProjectionKind<'tcx>>,
 }
 
 impl<'tcx> AscribeUserType<'tcx> {
     pub fn new(
         mir_ty: Ty<'tcx>,
-        variance: ty::Variance,
         def_id: DefId,
         user_substs: UserSubsts<'tcx>,
-        projs: &'tcx ty::List<ProjectionKind<'tcx>>,
     ) -> Self {
-        Self { mir_ty, variance, def_id, user_substs, projs }
+        Self { mir_ty,  def_id, user_substs }
     }
 }
 
@@ -52,19 +47,19 @@ impl<'gcx: 'tcx, 'tcx> super::QueryTypeOp<'gcx, 'tcx> for AscribeUserType<'tcx>
 
 BraceStructTypeFoldableImpl! {
     impl<'tcx> TypeFoldable<'tcx> for AscribeUserType<'tcx> {
-        mir_ty, variance, def_id, user_substs, projs
+        mir_ty, def_id, user_substs
     }
 }
 
 BraceStructLiftImpl! {
     impl<'a, 'tcx> Lift<'tcx> for AscribeUserType<'a> {
         type Lifted = AscribeUserType<'tcx>;
-        mir_ty, variance, def_id, user_substs, projs
+        mir_ty, def_id, user_substs
     }
 }
 
 impl_stable_hash_for! {
     struct AscribeUserType<'tcx> {
-        mir_ty, variance, def_id, user_substs, projs
+        mir_ty, def_id, user_substs
     }
 }
diff --git a/src/librustc/traits/query/type_op/custom.rs b/src/librustc/traits/query/type_op/custom.rs
index 0756d2eed8aea..7e38282cc1adc 100644
--- a/src/librustc/traits/query/type_op/custom.rs
+++ b/src/librustc/traits/query/type_op/custom.rs
@@ -1,12 +1,12 @@
-use infer::{InferCtxt, InferOk};
+use crate::infer::{InferCtxt, InferOk};
 use std::fmt;
-use traits::query::Fallible;
+use crate::traits::query::Fallible;
 
-use infer::canonical::query_response;
-use infer::canonical::QueryRegionConstraint;
+use crate::infer::canonical::query_response;
+use crate::infer::canonical::QueryRegionConstraint;
 use std::rc::Rc;
 use syntax::source_map::DUMMY_SP;
-use traits::{ObligationCause, TraitEngine, TraitEngineExt};
+use crate::traits::{ObligationCause, TraitEngine, TraitEngineExt};
 
 pub struct CustomTypeOp<F, G> {
     closure: F,
diff --git a/src/librustc/traits/query/type_op/eq.rs b/src/librustc/traits/query/type_op/eq.rs
index 7acb8ccb0d319..5c3ccc9a99537 100644
--- a/src/librustc/traits/query/type_op/eq.rs
+++ b/src/librustc/traits/query/type_op/eq.rs
@@ -1,6 +1,6 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::Fallible;
-use ty::{ParamEnvAnd, Ty, TyCtxt};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::Fallible;
+use crate::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct Eq<'tcx> {
diff --git a/src/librustc/traits/query/type_op/implied_outlives_bounds.rs b/src/librustc/traits/query/type_op/implied_outlives_bounds.rs
index f4a825a669b48..c48ca33b13fbc 100644
--- a/src/librustc/traits/query/type_op/implied_outlives_bounds.rs
+++ b/src/librustc/traits/query/type_op/implied_outlives_bounds.rs
@@ -1,7 +1,7 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::outlives_bounds::OutlivesBound;
-use traits::query::Fallible;
-use ty::{ParamEnvAnd, Ty, TyCtxt};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::outlives_bounds::OutlivesBound;
+use crate::traits::query::Fallible;
+use crate::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct ImpliedOutlivesBounds<'tcx> {
diff --git a/src/librustc/traits/query/type_op/mod.rs b/src/librustc/traits/query/type_op/mod.rs
index 6e5a6080976c0..fd13acc7796f8 100644
--- a/src/librustc/traits/query/type_op/mod.rs
+++ b/src/librustc/traits/query/type_op/mod.rs
@@ -1,14 +1,14 @@
-use infer::canonical::{
+use crate::infer::canonical::{
     Canonical, Canonicalized, CanonicalizedQueryResponse, OriginalQueryValues,
     QueryRegionConstraint, QueryResponse,
 };
-use infer::{InferCtxt, InferOk};
+use crate::infer::{InferCtxt, InferOk};
 use std::fmt;
 use std::rc::Rc;
-use traits::query::Fallible;
-use traits::ObligationCause;
-use ty::fold::TypeFoldable;
-use ty::{Lift, ParamEnvAnd, TyCtxt};
+use crate::traits::query::Fallible;
+use crate::traits::ObligationCause;
+use crate::ty::fold::TypeFoldable;
+use crate::ty::{Lift, ParamEnvAnd, TyCtxt};
 
 pub mod ascribe_user_type;
 pub mod custom;
diff --git a/src/librustc/traits/query/type_op/normalize.rs b/src/librustc/traits/query/type_op/normalize.rs
index 98afe2abdbf05..e3d7a4d57a564 100644
--- a/src/librustc/traits/query/type_op/normalize.rs
+++ b/src/librustc/traits/query/type_op/normalize.rs
@@ -1,8 +1,8 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
 use std::fmt;
-use traits::query::Fallible;
-use ty::fold::TypeFoldable;
-use ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt};
+use crate::traits::query::Fallible;
+use crate::ty::fold::TypeFoldable;
+use crate::ty::{self, Lift, ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct Normalize<T> {
@@ -52,7 +52,7 @@ pub trait Normalizable<'gcx, 'tcx>: fmt::Debug + TypeFoldable<'tcx> + Lift<'gcx>
         canonicalized: Canonicalized<'gcx, ParamEnvAnd<'tcx, Normalize<Self>>>,
     ) -> Fallible<CanonicalizedQueryResponse<'gcx, Self>>;
 
-    /// Convert from the `'gcx` (lifted) form of `Self` into the `tcx`
+    /// Converts from the `'gcx` (lifted) form of `Self` into the `tcx`
     /// form of `Self`.
     fn shrink_to_tcx_lifetime(
         v: &'a CanonicalizedQueryResponse<'gcx, Self>,
diff --git a/src/librustc/traits/query/type_op/outlives.rs b/src/librustc/traits/query/type_op/outlives.rs
index 108aa373e039c..fc0c1c022fc80 100644
--- a/src/librustc/traits/query/type_op/outlives.rs
+++ b/src/librustc/traits/query/type_op/outlives.rs
@@ -1,8 +1,8 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::dropck_outlives::trivial_dropck_outlives;
-use traits::query::dropck_outlives::DropckOutlivesResult;
-use traits::query::Fallible;
-use ty::{ParamEnvAnd, Ty, TyCtxt};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::dropck_outlives::trivial_dropck_outlives;
+use crate::traits::query::dropck_outlives::DropckOutlivesResult;
+use crate::traits::query::Fallible;
+use crate::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug)]
 pub struct DropckOutlives<'tcx> {
diff --git a/src/librustc/traits/query/type_op/prove_predicate.rs b/src/librustc/traits/query/type_op/prove_predicate.rs
index d9eb89c9fc7c8..50dedf6e87f40 100644
--- a/src/librustc/traits/query/type_op/prove_predicate.rs
+++ b/src/librustc/traits/query/type_op/prove_predicate.rs
@@ -1,6 +1,6 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::Fallible;
-use ty::{ParamEnvAnd, Predicate, TyCtxt};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::Fallible;
+use crate::ty::{ParamEnvAnd, Predicate, TyCtxt};
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct ProvePredicate<'tcx> {
diff --git a/src/librustc/traits/query/type_op/subtype.rs b/src/librustc/traits/query/type_op/subtype.rs
index f001c7ea10a17..c45fb06313e16 100644
--- a/src/librustc/traits/query/type_op/subtype.rs
+++ b/src/librustc/traits/query/type_op/subtype.rs
@@ -1,6 +1,6 @@
-use infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
-use traits::query::Fallible;
-use ty::{ParamEnvAnd, Ty, TyCtxt};
+use crate::infer::canonical::{Canonical, Canonicalized, CanonicalizedQueryResponse, QueryResponse};
+use crate::traits::query::Fallible;
+use crate::ty::{ParamEnvAnd, Ty, TyCtxt};
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct Subtype<'tcx> {
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index 6db6fe31fba70..05fb40ac10a07 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -27,25 +27,25 @@ use super::{
     VtableGeneratorData, VtableImplData, VtableObjectData, VtableTraitAliasData,
 };
 
-use dep_graph::{DepKind, DepNodeIndex};
-use hir::def_id::DefId;
-use infer::{InferCtxt, InferOk, TypeFreshener};
-use middle::lang_items;
-use mir::interpret::GlobalId;
-use ty::fast_reject;
-use ty::relate::TypeRelation;
-use ty::subst::{Subst, Substs};
-use ty::{self, ToPolyTraitRef, ToPredicate, Ty, TyCtxt, TypeFoldable};
-
-use hir;
+use crate::dep_graph::{DepKind, DepNodeIndex};
+use crate::hir::def_id::DefId;
+use crate::infer::{CombinedSnapshot, InferCtxt, InferOk, PlaceholderMap, TypeFreshener};
+use crate::middle::lang_items;
+use crate::mir::interpret::GlobalId;
+use crate::ty::fast_reject;
+use crate::ty::relate::TypeRelation;
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::{self, ToPolyTraitRef, ToPredicate, Ty, TyCtxt, TypeFoldable};
+
+use crate::hir;
 use rustc_data_structures::bit_set::GrowableBitSet;
 use rustc_data_structures::sync::Lock;
 use rustc_target::spec::abi::Abi;
 use std::cmp;
-use std::fmt;
+use std::fmt::{self, Display};
 use std::iter;
 use std::rc::Rc;
-use util::nodemap::{FxHashMap, FxHashSet};
+use crate::util::nodemap::{FxHashMap, FxHashSet};
 
 pub struct SelectionContext<'cx, 'gcx: 'cx + 'tcx, 'tcx: 'cx> {
     infcx: &'cx InferCtxt<'cx, 'gcx, 'tcx>,
@@ -103,7 +103,7 @@ impl IntercrateAmbiguityCause {
     /// See #23980 for details.
     pub fn add_intercrate_ambiguity_hint<'a, 'tcx>(
         &self,
-        err: &mut ::errors::DiagnosticBuilder<'_>,
+        err: &mut errors::DiagnosticBuilder<'_>,
     ) {
         err.note(&self.intercrate_ambiguity_hint());
     }
@@ -162,11 +162,11 @@ pub struct SelectionCache<'tcx> {
 }
 
 /// The selection process begins by considering all impls, where
-/// clauses, and so forth that might resolve an obligation.  Sometimes
+/// clauses, and so forth that might resolve an obligation. Sometimes
 /// we'll be able to say definitively that (e.g.) an impl does not
 /// apply to the obligation: perhaps it is defined for `usize` but the
 /// obligation is for `int`. In that case, we drop the impl out of the
-/// list.  But the other cases are considered *candidates*.
+/// list. But the other cases are considered *candidates*.
 ///
 /// For selection to succeed, there must be exactly one matching
 /// candidate. If the obligation is fully known, this is guaranteed
@@ -331,7 +331,7 @@ enum BuiltinImplConditions<'tcx> {
 ///     - `EvaluatedToErr` implies `EvaluatedToRecur`
 ///     - the "union" of evaluation results is equal to their maximum -
 ///     all the "potential success" candidates can potentially succeed,
-///     so they are no-ops when unioned with a definite error, and within
+///     so they are noops when unioned with a definite error, and within
 ///     the categories it's easy to see that the unions are correct.
 pub enum EvaluationResult {
     /// Evaluation successful
@@ -383,31 +383,30 @@ pub enum EvaluationResult {
     /// ```
     ///
     /// When we try to prove it, we first go the first option, which
-    /// recurses. This shows us that the impl is "useless" - it won't
+    /// recurses. This shows us that the impl is "useless" -- it won't
     /// tell us that `T: Trait` unless it already implemented `Trait`
     /// by some other means. However, that does not prevent `T: Trait`
     /// does not hold, because of the bound (which can indeed be satisfied
     /// by `SomeUnsizedType` from another crate).
-    ///
-    /// FIXME: when an `EvaluatedToRecur` goes past its parent root, we
-    /// ought to convert it to an `EvaluatedToErr`, because we know
-    /// there definitely isn't a proof tree for that obligation. Not
-    /// doing so is still sound - there isn't any proof tree, so the
-    /// branch still can't be a part of a minimal one - but does not
-    /// re-enable caching.
+    //
+    // FIXME: when an `EvaluatedToRecur` goes past its parent root, we
+    // ought to convert it to an `EvaluatedToErr`, because we know
+    // there definitely isn't a proof tree for that obligation. Not
+    // doing so is still sound -- there isn't any proof tree, so the
+    // branch still can't be a part of a minimal one -- but does not re-enable caching.
     EvaluatedToRecur,
-    /// Evaluation failed
+    /// Evaluation failed.
     EvaluatedToErr,
 }
 
 impl EvaluationResult {
-    /// True if this evaluation result is known to apply, even
+    /// Returns `true` if this evaluation result is known to apply, even
     /// considering outlives constraints.
     pub fn must_apply_considering_regions(self) -> bool {
         self == EvaluatedToOk
     }
 
-    /// True if this evaluation result is known to apply, ignoring
+    /// Returns `true` if this evaluation result is known to apply, ignoring
     /// outlives constraints.
     pub fn must_apply_modulo_regions(self) -> bool {
         self <= EvaluatedToOkModuloRegions
@@ -629,7 +628,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         obligation: &PredicateObligation<'tcx>,
     ) -> Result<EvaluationResult, OverflowError> {
         self.evaluation_probe(|this| {
-            this.evaluate_predicate_recursively(TraitObligationStackList::empty(), obligation)
+            this.evaluate_predicate_recursively(TraitObligationStackList::empty(),
+                obligation.clone())
         })
     }
 
@@ -655,12 +655,12 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         predicates: I,
     ) -> Result<EvaluationResult, OverflowError>
     where
-        I: IntoIterator<Item = &'a PredicateObligation<'tcx>>,
+        I: IntoIterator<Item = PredicateObligation<'tcx>>,
         'tcx: 'a,
     {
         let mut result = EvaluatedToOk;
         for obligation in predicates {
-            let eval = self.evaluate_predicate_recursively(stack, obligation)?;
+            let eval = self.evaluate_predicate_recursively(stack, obligation.clone())?;
             debug!(
                 "evaluate_predicate_recursively({:?}) = {:?}",
                 obligation, eval
@@ -679,9 +679,19 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     fn evaluate_predicate_recursively<'o>(
         &mut self,
         previous_stack: TraitObligationStackList<'o, 'tcx>,
-        obligation: &PredicateObligation<'tcx>,
+        obligation: PredicateObligation<'tcx>,
     ) -> Result<EvaluationResult, OverflowError> {
-        debug!("evaluate_predicate_recursively({:?})", obligation);
+        debug!("evaluate_predicate_recursively(previous_stack={:?}, obligation={:?})",
+            previous_stack.head(), obligation);
+
+        // Previous_stack stores a TraitObligatiom, while 'obligation' is
+        // a PredicateObligation. These are distinct types, so we can't
+        // use any Option combinator method that would force them to be
+        // the same
+        match previous_stack.head() {
+            Some(h) => self.check_recursion_limit(&obligation, h.obligation)?,
+            None => self.check_recursion_limit(&obligation, &obligation)?
+        }
 
         match obligation.predicate {
             ty::Predicate::Trait(ref t) => {
@@ -695,8 +705,9 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 match self.infcx
                     .subtype_predicate(&obligation.cause, obligation.param_env, p)
                 {
-                    Some(Ok(InferOk { obligations, .. })) => {
-                        self.evaluate_predicates_recursively(previous_stack, &obligations)
+                    Some(Ok(InferOk { mut obligations, .. })) => {
+                        self.add_depth(obligations.iter_mut(), obligation.recursion_depth);
+                        self.evaluate_predicates_recursively(previous_stack,obligations.into_iter())
                     }
                     Some(Err(_)) => Ok(EvaluatedToErr),
                     None => Ok(EvaluatedToAmbig),
@@ -710,8 +721,9 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 ty,
                 obligation.cause.span,
             ) {
-                Some(obligations) => {
-                    self.evaluate_predicates_recursively(previous_stack, obligations.iter())
+                Some(mut obligations) => {
+                    self.add_depth(obligations.iter_mut(), obligation.recursion_depth);
+                    self.evaluate_predicates_recursively(previous_stack, obligations.into_iter())
                 }
                 None => Ok(EvaluatedToAmbig),
             },
@@ -733,10 +745,11 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             ty::Predicate::Projection(ref data) => {
                 let project_obligation = obligation.with(data.clone());
                 match project::poly_project_and_unify_type(self, &project_obligation) {
-                    Ok(Some(subobligations)) => {
+                    Ok(Some(mut subobligations)) => {
+                        self.add_depth(subobligations.iter_mut(), obligation.recursion_depth);
                         let result = self.evaluate_predicates_recursively(
                             previous_stack,
-                            subobligations.iter(),
+                            subobligations.into_iter(),
                         );
                         if let Some(key) =
                             ProjectionCacheKey::from_poly_projection_predicate(self, data)
@@ -967,8 +980,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     /// that recursion is ok. This routine returns true if the top of the
     /// stack (`cycle[0]`):
     ///
-    /// - is a defaulted trait, and
-    /// - it also appears in the backtrace at some position `X`; and,
+    /// - is a defaulted trait,
+    /// - it also appears in the backtrace at some position `X`,
     /// - all the predicates at positions `X..` between `X` an the top are
     ///   also defaulted traits.
     pub fn coinductive_match<I>(&mut self, cycle: I) -> bool
@@ -989,7 +1002,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     }
 
     /// Further evaluate `candidate` to decide whether all type parameters match and whether nested
-    /// obligations are met. Returns true if `candidate` remains viable after this further
+    /// obligations are met. Returns whether `candidate` remains viable after this further
     /// scrutiny.
     fn evaluate_candidate<'o>(
         &mut self,
@@ -1005,7 +1018,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             match this.confirm_candidate(stack.obligation, candidate) {
                 Ok(selection) => this.evaluate_predicates_recursively(
                     stack.list(),
-                    selection.nested_obligations().iter(),
+                    selection.nested_obligations().into_iter()
                 ),
                 Err(..) => Ok(EvaluatedToErr),
             }
@@ -1080,6 +1093,45 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             .insert(trait_ref, WithDepNode::new(dep_node, result));
     }
 
+    // For various reasons, it's possible for a subobligation
+    // to have a *lower* recursion_depth than the obligation used to create it.
+    // Projection sub-obligations may be returned from the projection cache,
+    // which results in obligations with an 'old' recursion_depth.
+    // Additionally, methods like ty::wf::obligations and
+    // InferCtxt.subtype_predicate produce subobligations without
+    // taking in a 'parent' depth, causing the generated subobligations
+    // to have a recursion_depth of 0
+    //
+    // To ensure that obligation_depth never decreasees, we force all subobligations
+    // to have at least the depth of the original obligation.
+    fn add_depth<T: 'cx, I: Iterator<Item = &'cx mut Obligation<'tcx, T>>>(&self, it: I,
+                                                                           min_depth: usize) {
+        it.for_each(|o| o.recursion_depth = cmp::max(min_depth, o.recursion_depth) + 1);
+    }
+
+    // Check that the recursion limit has not been exceeded.
+    //
+    // The weird return type of this function allows it to be used with the 'try' (?)
+    // operator within certain functions
+    fn check_recursion_limit<T: Display + TypeFoldable<'tcx>, V: Display + TypeFoldable<'tcx>>(
+        &self,
+        obligation: &Obligation<'tcx, T>,
+        error_obligation: &Obligation<'tcx, V>
+    ) -> Result<(), OverflowError>  {
+        let recursion_limit = *self.infcx.tcx.sess.recursion_limit.get();
+        if obligation.recursion_depth >= recursion_limit {
+            match self.query_mode {
+                TraitQueryMode::Standard => {
+                    self.infcx().report_overflow_error(error_obligation, true);
+                }
+                TraitQueryMode::Canonical => {
+                    return Err(OverflowError);
+                }
+            }
+        }
+        Ok(())
+    }
+
     ///////////////////////////////////////////////////////////////////////////
     // CANDIDATE ASSEMBLY
     //
@@ -1096,17 +1148,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     ) -> SelectionResult<'tcx, SelectionCandidate<'tcx>> {
         // Watch out for overflow. This intentionally bypasses (and does
         // not update) the cache.
-        let recursion_limit = *self.infcx.tcx.sess.recursion_limit.get();
-        if stack.obligation.recursion_depth >= recursion_limit {
-            match self.query_mode {
-                TraitQueryMode::Standard => {
-                    self.infcx().report_overflow_error(&stack.obligation, true);
-                }
-                TraitQueryMode::Canonical => {
-                    return Err(Overflow);
-                }
-            }
-        }
+        self.check_recursion_limit(&stack.obligation, &stack.obligation)?;
+
 
         // Check the cache. Note that we freshen the trait-ref
         // separately rather than using `stack.fresh_trait_ref` --
@@ -1390,7 +1433,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         }
     }
 
-    /// Returns true if the global caches can be used.
+    /// Returns `true` if the global caches can be used.
     /// Do note that if the type itself is not in the
     /// global tcx, the local caches will be used.
     fn can_use_global_caches(&self, param_env: ty::ParamEnv<'tcx>) -> bool {
@@ -1624,8 +1667,11 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             _ => return,
         }
 
-        let result = self.infcx.probe(|_| {
-            self.match_projection_obligation_against_definition_bounds(obligation)
+        let result = self.infcx.probe(|snapshot| {
+            self.match_projection_obligation_against_definition_bounds(
+                obligation,
+                snapshot,
+            )
         });
 
         if result {
@@ -1636,18 +1682,19 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     fn match_projection_obligation_against_definition_bounds(
         &mut self,
         obligation: &TraitObligation<'tcx>,
+        snapshot: &CombinedSnapshot<'_, 'tcx>,
     ) -> bool {
         let poly_trait_predicate = self.infcx()
             .resolve_type_vars_if_possible(&obligation.predicate);
-        let (skol_trait_predicate, _) = self.infcx()
+        let (placeholder_trait_predicate, placeholder_map) = self.infcx()
             .replace_bound_vars_with_placeholders(&poly_trait_predicate);
         debug!(
             "match_projection_obligation_against_definition_bounds: \
-             skol_trait_predicate={:?}",
-            skol_trait_predicate,
+             placeholder_trait_predicate={:?}",
+            placeholder_trait_predicate,
         );
 
-        let (def_id, substs) = match skol_trait_predicate.trait_ref.self_ty().sty {
+        let (def_id, substs) = match placeholder_trait_predicate.trait_ref.self_ty().sty {
             ty::Projection(ref data) => (data.trait_ref(self.tcx()).def_id, data.substs),
             ty::Opaque(def_id, substs) => (def_id, substs),
             _ => {
@@ -1655,7 +1702,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                     obligation.cause.span,
                     "match_projection_obligation_against_definition_bounds() called \
                      but self-ty is not a projection: {:?}",
-                    skol_trait_predicate.trait_ref.self_ty()
+                    placeholder_trait_predicate.trait_ref.self_ty()
                 );
             }
         };
@@ -1680,7 +1727,9 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                     self.match_projection(
                         obligation,
                         bound.clone(),
-                        skol_trait_predicate.trait_ref.clone(),
+                        placeholder_trait_predicate.trait_ref.clone(),
+                        &placeholder_map,
+                        snapshot,
                     )
                 })
             });
@@ -1697,7 +1746,9 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                 let result = self.match_projection(
                     obligation,
                     bound,
-                    skol_trait_predicate.trait_ref.clone(),
+                    placeholder_trait_predicate.trait_ref.clone(),
+                    &placeholder_map,
+                    snapshot,
                 );
 
                 assert!(result);
@@ -1710,13 +1761,17 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         &mut self,
         obligation: &TraitObligation<'tcx>,
         trait_bound: ty::PolyTraitRef<'tcx>,
-        skol_trait_ref: ty::TraitRef<'tcx>,
+        placeholder_trait_ref: ty::TraitRef<'tcx>,
+        placeholder_map: &PlaceholderMap<'tcx>,
+        snapshot: &CombinedSnapshot<'_, 'tcx>,
     ) -> bool {
-        debug_assert!(!skol_trait_ref.has_escaping_bound_vars());
+        debug_assert!(!placeholder_trait_ref.has_escaping_bound_vars());
         self.infcx
             .at(&obligation.cause, obligation.param_env)
-            .sup(ty::Binder::dummy(skol_trait_ref), trait_bound)
+            .sup(ty::Binder::dummy(placeholder_trait_ref), trait_bound)
             .is_ok()
+            &&
+            self.infcx.leak_check(false, placeholder_map, snapshot).is_ok()
     }
 
     /// Given an obligation like `<SomeTrait for T>`, search the obligations that the caller
@@ -1767,7 +1822,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         self.evaluation_probe(|this| {
             match this.match_where_clause_trait_ref(stack.obligation, where_clause_trait_ref) {
                 Ok(obligations) => {
-                    this.evaluate_predicates_recursively(stack.list(), obligations.iter())
+                    this.evaluate_predicates_recursively(stack.list(), obligations.into_iter())
                 }
                 Err(()) => Ok(EvaluatedToErr),
             }
@@ -1806,7 +1861,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         Ok(())
     }
 
-    /// Check for the artificial impl that the compiler will create for an obligation like `X :
+    /// Checks for the artificial impl that the compiler will create for an obligation like `X :
     /// FnMut<..>` where `X` is a closure type.
     ///
     /// Note: the type parameters on a closure candidate are modeled as *output* type
@@ -1917,8 +1972,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             obligation.predicate.def_id(),
             obligation.predicate.skip_binder().trait_ref.self_ty(),
             |impl_def_id| {
-                self.infcx.probe(|_| {
-                    if let Ok(_substs) = self.match_impl(impl_def_id, obligation)
+                self.infcx.probe(|snapshot| {
+                    if let Ok(_substs) = self.match_impl(impl_def_id, obligation, snapshot)
                     {
                         candidates.vec.push(ImplCandidate(impl_def_id));
                     }
@@ -1973,6 +2028,24 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                     // the auto impl might apply, we don't know
                     candidates.ambiguous = true;
                 }
+                ty::Generator(_, _, movability)
+                    if self.tcx().lang_items().unpin_trait() == Some(def_id) =>
+                {
+                    match movability {
+                        hir::GeneratorMovability::Static => {
+                            // Immovable generators are never `Unpin`, so
+                            // suppress the normal auto-impl candidate for it.
+                        }
+                        hir::GeneratorMovability::Movable => {
+                            // Movable generators are always `Unpin`, so add an
+                            // unconditional builtin candidate.
+                            candidates.vec.push(BuiltinCandidate {
+                                has_nested: false,
+                            });
+                        }
+                    }
+                }
+
                 _ => candidates.vec.push(AutoImplCandidate(def_id.clone())),
             }
         }
@@ -2154,7 +2227,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
 
         let def_id = obligation.predicate.def_id();
 
-        if ty::is_trait_alias(self.tcx(), def_id) {
+        if self.tcx().is_trait_alias(def_id) {
             candidates.vec.push(TraitAliasCandidate(def_id.clone()));
         }
 
@@ -2169,8 +2242,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     // type variables and then we also attempt to evaluate recursive
     // bounds to see if they are satisfied.
 
-    /// Returns true if `victim` should be dropped in favor of
-    /// `other`.  Generally speaking we will drop duplicate
+    /// Returns `true` if `victim` should be dropped in favor of
+    /// `other`. Generally speaking we will drop duplicate
     /// candidates and prefer where-clause candidates.
     ///
     /// See the comment for "SelectionCandidate" for more details.
@@ -2697,9 +2770,12 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     }
 
     fn confirm_projection_candidate(&mut self, obligation: &TraitObligation<'tcx>) {
-        self.infcx.in_snapshot(|_| {
+        self.infcx.in_snapshot(|snapshot| {
             let result =
-                self.match_projection_obligation_against_definition_bounds(obligation);
+                self.match_projection_obligation_against_definition_bounds(
+                    obligation,
+                    snapshot,
+                );
             assert!(result);
         })
     }
@@ -2851,8 +2927,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
 
         // First, create the substitutions by matching the impl again,
         // this time not in a probe.
-        self.infcx.in_snapshot(|_| {
-            let substs = self.rematch_impl(impl_def_id, obligation);
+        self.infcx.in_snapshot(|snapshot| {
+            let substs = self.rematch_impl(impl_def_id, obligation, snapshot);
             debug!("confirm_impl_candidate: substs={:?}", substs);
             let cause = obligation.derived_cause(ImplDerivedObligation);
             self.vtable_impl(
@@ -3159,7 +3235,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     /// we currently treat the input type parameters on the trait as
     /// outputs. This means that when we have a match we have only
     /// considered the self type, so we have to go back and make sure
-    /// to relate the argument types too.  This is kind of wrong, but
+    /// to relate the argument types too. This is kind of wrong, but
     /// since we control the full set of impls, also not that wrong,
     /// and it DOES yield better error messages (since we don't report
     /// errors as if there is no applicable impl, but rather report
@@ -3173,7 +3249,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     ///     impl Fn(int) for Closure { ... }
     ///
     /// Now imagine our obligation is `Fn(usize) for Closure`. So far
-    /// we have matched the self-type `Closure`. At this point we'll
+    /// we have matched the self type `Closure`. At this point we'll
     /// compare the `int` to `usize` and generate an error.
     ///
     /// Note that this checking occurs *after* the impl has selected,
@@ -3239,9 +3315,27 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
                     tcx.mk_existential_predicates(iter)
                 });
                 let source_trait = tcx.mk_dynamic(existential_predicates, r_b);
+
+                // Require that the traits involved in this upcast are **equal**;
+                // only the **lifetime bound** is changed.
+                //
+                // FIXME: This condition is arguably too strong -- it
+                // would suffice for the source trait to be a
+                // *subtype* of the target trait. In particular
+                // changing from something like `for<'a, 'b> Foo<'a,
+                // 'b>` to `for<'a> Foo<'a, 'a>` should be
+                // permitted. And, indeed, in the in commit
+                // 904a0bde93f0348f69914ee90b1f8b6e4e0d7cbc, this
+                // condition was loosened. However, when the leak check was added
+                // back, using subtype here actually guies the coercion code in
+                // such a way that it accepts `old-lub-glb-object.rs`. This is probably
+                // a good thing, but I've modified this to `.eq` because I want
+                // to continue rejecting that test (as we have done for quite some time)
+                // before we are firmly comfortable with what our behavior
+                // should be there. -nikomatsakis
                 let InferOk { obligations, .. } = self.infcx
                     .at(&obligation.cause, obligation.param_env)
-                    .sup(target, source_trait)
+                    .eq(target, source_trait) // FIXME -- see below
                     .map_err(|_| Unimplemented)?;
                 nested.extend(obligations);
 
@@ -3443,8 +3537,9 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         &mut self,
         impl_def_id: DefId,
         obligation: &TraitObligation<'tcx>,
+        snapshot: &CombinedSnapshot<'_, 'tcx>,
     ) -> Normalized<'tcx, &'tcx Substs<'tcx>> {
-        match self.match_impl(impl_def_id, obligation) {
+        match self.match_impl(impl_def_id, obligation, snapshot) {
             Ok(substs) => substs,
             Err(()) => {
                 bug!(
@@ -3460,6 +3555,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
         &mut self,
         impl_def_id: DefId,
         obligation: &TraitObligation<'tcx>,
+        snapshot: &CombinedSnapshot<'_, 'tcx>,
     ) -> Result<Normalized<'tcx, &'tcx Substs<'tcx>>, ()> {
         let impl_trait_ref = self.tcx().impl_trait_ref(impl_def_id).unwrap();
 
@@ -3470,7 +3566,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             return Err(());
         }
 
-        let (skol_obligation, _) = self.infcx()
+        let (skol_obligation, placeholder_map) = self.infcx()
             .replace_bound_vars_with_placeholders(&obligation.predicate);
         let skol_obligation_trait_ref = skol_obligation.trait_ref;
 
@@ -3502,6 +3598,11 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             .map_err(|e| debug!("match_impl: failed eq_trait_refs due to `{}`", e))?;
         nested_obligations.extend(obligations);
 
+        if let Err(e) = self.infcx.leak_check(false, &placeholder_map, snapshot) {
+            debug!("match_impl: failed leak check due to `{}`", e);
+            return Err(());
+        }
+
         debug!("match_impl: success impl_substs={:?}", impl_substs);
         Ok(Normalized {
             value: impl_substs,
@@ -3535,7 +3636,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     }
 
     /// Normalize `where_clause_trait_ref` and try to match it against
-    /// `obligation`.  If successful, return any predicates that
+    /// `obligation`. If successful, return any predicates that
     /// result from the normalization. Normalization is necessary
     /// because where-clauses are stored in the parameter environment
     /// unnormalized.
@@ -3802,6 +3903,10 @@ impl<'o, 'tcx> TraitObligationStackList<'o, 'tcx> {
     fn with(r: &'o TraitObligationStack<'o, 'tcx>) -> TraitObligationStackList<'o, 'tcx> {
         TraitObligationStackList { head: Some(r) }
     }
+
+    fn head(&self) -> Option<&'o TraitObligationStack<'o, 'tcx>> {
+        self.head
+    }
 }
 
 impl<'o, 'tcx> Iterator for TraitObligationStackList<'o, 'tcx> {
diff --git a/src/librustc/traits/specialize/mod.rs b/src/librustc/traits/specialize/mod.rs
index e5ed16e755860..804f1b9d820a2 100644
--- a/src/librustc/traits/specialize/mod.rs
+++ b/src/librustc/traits/specialize/mod.rs
@@ -11,16 +11,16 @@
 
 pub mod specialization_graph;
 
-use hir::def_id::DefId;
-use infer::{InferCtxt, InferOk};
-use lint;
-use traits::{self, coherence, FutureCompatOverlapErrorKind, ObligationCause, TraitEngine};
+use crate::hir::def_id::DefId;
+use crate::infer::{InferCtxt, InferOk};
+use crate::lint;
+use crate::traits::{self, coherence, FutureCompatOverlapErrorKind, ObligationCause, TraitEngine};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::DUMMY_SP;
-use traits::select::IntercrateAmbiguityCause;
-use ty::{self, TyCtxt, TypeFoldable};
-use ty::subst::{Subst, Substs};
+use crate::traits::select::IntercrateAmbiguityCause;
+use crate::ty::{self, TyCtxt, TypeFoldable};
+use crate::ty::subst::{Subst, Substs};
 
 use super::{SelectionContext, FulfillmentContext};
 use super::util::impl_trait_ref_and_oblig;
@@ -58,12 +58,12 @@ pub struct OverlapError {
 /// Suppose we have selected "source impl" with `V` instantiated with `u32`.
 /// This function will produce a substitution with `T` and `U` both mapping to `u32`.
 ///
-/// Where clauses add some trickiness here, because they can be used to "define"
+/// where-clauses add some trickiness here, because they can be used to "define"
 /// an argument indirectly:
 ///
 /// ```rust
 /// impl<'a, I, T: 'a> Iterator for Cloned<I>
-///    where I: Iterator<Item=&'a T>, T: Clone
+///    where I: Iterator<Item = &'a T>, T: Clone
 /// ```
 ///
 /// In a case like this, the substitution for `T` is determined indirectly,
@@ -145,10 +145,10 @@ pub fn find_associated_item<'a, 'tcx>(
     }
 }
 
-/// Is impl1 a specialization of impl2?
+/// Is `impl1` a specialization of `impl2`?
 ///
 /// Specialization is determined by the sets of types to which the impls apply;
-/// impl1 specializes impl2 if it applies to a subset of the types impl2 applies
+/// `impl1` specializes `impl2` if it applies to a subset of the types `impl2` applies
 /// to.
 pub(super) fn specializes<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                     (impl1_def_id, impl2_def_id): (DefId, DefId))
diff --git a/src/librustc/traits/specialize/specialization_graph.rs b/src/librustc/traits/specialize/specialization_graph.rs
index e5780a26a1918..561859c7c3177 100644
--- a/src/librustc/traits/specialize/specialization_graph.rs
+++ b/src/librustc/traits/specialize/specialization_graph.rs
@@ -1,16 +1,16 @@
 use super::OverlapError;
 
-use hir::def_id::DefId;
-use ich::{self, StableHashingContext};
+use crate::hir::def_id::DefId;
+use crate::ich::{self, StableHashingContext};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
-use traits;
-use ty::{self, TyCtxt, TypeFoldable};
-use ty::fast_reject::{self, SimplifiedType};
+use crate::traits;
+use crate::ty::{self, TyCtxt, TypeFoldable};
+use crate::ty::fast_reject::{self, SimplifiedType};
 use rustc_data_structures::sync::Lrc;
 use syntax::ast::Ident;
-use util::captures::Captures;
-use util::nodemap::{DefIdMap, FxHashMap};
+use crate::util::captures::Captures;
+use crate::util::nodemap::{DefIdMap, FxHashMap};
 
 /// A per-trait graph of impls in specialization order. At the moment, this
 /// graph forms a tree rooted with the trait itself, with all other nodes
@@ -97,7 +97,7 @@ impl<'a, 'gcx, 'tcx> Children {
         }
     }
 
-    /// Remove an impl from this set of children. Used when replacing
+    /// Removes an impl from this set of children. Used when replacing
     /// an impl with a parent. The impl must be present in the list of
     /// children already.
     fn remove_existing(&mut self,
@@ -399,7 +399,7 @@ impl<'a, 'gcx, 'tcx> Graph {
         self.children.entry(parent).or_default().insert_blindly(tcx, child);
     }
 
-    /// The parent of a given impl, which is the def id of the trait when the
+    /// The parent of a given impl, which is the `DefId` of the trait when the
     /// impl is a "specialization root".
     pub fn parent(&self, child: DefId) -> DefId {
         *self.parent.get(&child).unwrap()
@@ -489,7 +489,7 @@ impl<'a, 'gcx, 'tcx> Ancestors {
         trait_def_id: DefId,
     ) -> impl Iterator<Item = NodeItem<ty::AssociatedItem>> + Captures<'gcx> + Captures<'tcx> + 'a {
         self.flat_map(move |node| {
-            use ty::AssociatedKind::*;
+            use crate::ty::AssociatedKind::*;
             node.items(tcx).filter(move |impl_item| match (trait_item_kind, impl_item.kind) {
                 | (Const, Const)
                 | (Method, Method)
diff --git a/src/librustc/traits/structural_impls.rs b/src/librustc/traits/structural_impls.rs
index 2f5df022218fe..b5be1777fa0d8 100644
--- a/src/librustc/traits/structural_impls.rs
+++ b/src/librustc/traits/structural_impls.rs
@@ -1,9 +1,9 @@
 use chalk_engine;
 use smallvec::SmallVec;
-use traits;
-use traits::project::Normalized;
-use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
-use ty::{self, Lift, TyCtxt};
+use crate::traits;
+use crate::traits::project::Normalized;
+use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
+use crate::ty::{self, Lift, TyCtxt};
 use syntax::symbol::InternedString;
 
 use std::fmt;
@@ -163,7 +163,7 @@ impl<'tcx> fmt::Debug for traits::MismatchedProjectionTypes<'tcx> {
 
 impl<'tcx> fmt::Display for traits::WhereClause<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::WhereClause::*;
+        use crate::traits::WhereClause::*;
 
         // Bypass ppaux because it does not print out anonymous regions.
         fn write_region_name<'tcx>(
@@ -206,7 +206,7 @@ impl<'tcx> fmt::Display for traits::WhereClause<'tcx> {
 
 impl<'tcx> fmt::Display for traits::WellFormed<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::WellFormed::*;
+        use crate::traits::WellFormed::*;
 
         match self {
             Trait(trait_ref) => write!(fmt, "WellFormed({})", trait_ref),
@@ -217,7 +217,7 @@ impl<'tcx> fmt::Display for traits::WellFormed<'tcx> {
 
 impl<'tcx> fmt::Display for traits::FromEnv<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::FromEnv::*;
+        use crate::traits::FromEnv::*;
 
         match self {
             Trait(trait_ref) => write!(fmt, "FromEnv({})", trait_ref),
@@ -228,7 +228,7 @@ impl<'tcx> fmt::Display for traits::FromEnv<'tcx> {
 
 impl<'tcx> fmt::Display for traits::DomainGoal<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::DomainGoal::*;
+        use crate::traits::DomainGoal::*;
 
         match self {
             Holds(wc) => write!(fmt, "{}", wc),
@@ -246,7 +246,7 @@ impl<'tcx> fmt::Display for traits::DomainGoal<'tcx> {
 
 impl fmt::Display for traits::QuantifierKind {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::QuantifierKind::*;
+        use crate::traits::QuantifierKind::*;
 
         match self {
             Universal => write!(fmt, "forall"),
@@ -361,7 +361,7 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
 
 impl<'tcx> fmt::Display for traits::Goal<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::GoalKind::*;
+        use crate::traits::GoalKind::*;
 
         match self {
             Implies(hypotheses, goal) => {
@@ -420,7 +420,7 @@ impl<'tcx> fmt::Display for traits::ProgramClause<'tcx> {
 
 impl<'tcx> fmt::Display for traits::Clause<'tcx> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        use traits::Clause::*;
+        use crate::traits::Clause::*;
 
         match self {
             Implies(clause) => write!(fmt, "{}", clause),
@@ -513,10 +513,21 @@ impl<'a, 'tcx> Lift<'tcx> for traits::ObligationCauseCode<'a> {
                 trait_item_def_id,
             }),
             super::ExprAssignable => Some(super::ExprAssignable),
-            super::MatchExpressionArm { arm_span, source } => Some(super::MatchExpressionArm {
+            super::MatchExpressionArm {
                 arm_span,
-                source: source,
-            }),
+                source,
+                ref prior_arms,
+                last_ty,
+            } => {
+                tcx.lift(&last_ty).map(|last_ty| {
+                    super::MatchExpressionArm {
+                        arm_span,
+                        source,
+                        prior_arms: prior_arms.clone(),
+                        last_ty,
+                    }
+                })
+            }
             super::MatchExpressionArmPattern { span, ty } => {
                 tcx.lift(&ty).map(|ty| super::MatchExpressionArmPattern { span, ty })
             }
diff --git a/src/librustc/traits/util.rs b/src/librustc/traits/util.rs
index 5b7ba5386725e..754cc94073b10 100644
--- a/src/librustc/traits/util.rs
+++ b/src/librustc/traits/util.rs
@@ -1,10 +1,10 @@
-use hir;
-use hir::def_id::DefId;
-use traits::specialize::specialization_graph::NodeItem;
-use ty::{self, Ty, TyCtxt, ToPredicate, ToPolyTraitRef};
-use ty::outlives::Component;
-use ty::subst::{Kind, Subst, Substs};
-use util::nodemap::FxHashSet;
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::traits::specialize::specialization_graph::NodeItem;
+use crate::ty::{self, Ty, TyCtxt, ToPredicate, ToPolyTraitRef};
+use crate::ty::outlives::Component;
+use crate::ty::subst::{Kind, Subst, Substs};
+use crate::util::nodemap::FxHashSet;
 
 use super::{Obligation, ObligationCause, PredicateObligation, SelectionContext, Normalized};
 
@@ -525,9 +525,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     pub fn impl_is_default(self, node_item_def_id: DefId) -> bool {
-        match self.hir().as_local_node_id(node_item_def_id) {
-            Some(node_id) => {
-                let item = self.hir().expect_item(node_id);
+        match self.hir().as_local_hir_id(node_item_def_id) {
+            Some(hir_id) => {
+                let item = self.hir().expect_item_by_hir_id(hir_id);
                 if let hir::ItemKind::Impl(_, _, defaultness, ..) = item.node {
                     defaultness.is_default()
                 } else {
diff --git a/src/librustc/ty/_match.rs b/src/librustc/ty/_match.rs
index 34b94d4217d8b..07fa441bb8076 100644
--- a/src/librustc/ty/_match.rs
+++ b/src/librustc/ty/_match.rs
@@ -1,6 +1,6 @@
-use ty::{self, Ty, TyCtxt};
-use ty::error::TypeError;
-use ty::relate::{self, Relate, TypeRelation, RelateResult};
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::error::TypeError;
+use crate::ty::relate::{self, Relate, TypeRelation, RelateResult};
 
 /// A type "A" *matches* "B" if the fresh types in B could be
 /// substituted with values so as to make it equal to A. Matching is
diff --git a/src/librustc/ty/adjustment.rs b/src/librustc/ty/adjustment.rs
index 117112c0c75f4..ff4fc87542dc3 100644
--- a/src/librustc/ty/adjustment.rs
+++ b/src/librustc/ty/adjustment.rs
@@ -1,7 +1,7 @@
-use hir;
-use hir::def_id::DefId;
-use ty::{self, Ty, TyCtxt};
-use ty::subst::Substs;
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::subst::Substs;
 
 
 /// Represents coercing a value to a different type of value.
@@ -15,7 +15,7 @@ use ty::subst::Substs;
 ///    Here the pointer will be dereferenced N times (where a dereference can
 ///    happen to raw or borrowed pointers or any smart pointer which implements
 ///    Deref, including Box<_>). The types of dereferences is given by
-///    `autoderefs`.  It can then be auto-referenced zero or one times, indicated
+///    `autoderefs`. It can then be auto-referenced zero or one times, indicated
 ///    by `autoref`, to either a raw or borrowed pointer. In these cases unsize is
 ///    `false`.
 ///
@@ -38,7 +38,7 @@ use ty::subst::Substs;
 ///    stored in `unsize` is `Foo<[i32]>`, we don't store any further detail about
 ///    the underlying conversions from `[i32; 4]` to `[i32]`.
 ///
-/// 3. Coercing a `Box<T>` to `Box<dyn Trait>` is an interesting special case.  In
+/// 3. Coercing a `Box<T>` to `Box<dyn Trait>` is an interesting special case. In
 ///    that case, we have the pointer we need coming in, so there are no
 ///    autoderefs, and no autoref. Instead we just do the `Unsize` transformation.
 ///    At some point, of course, `Box` should move out of the compiler, in which
@@ -78,7 +78,7 @@ pub enum Adjust<'tcx> {
     /// This will do things like convert thin pointers to fat
     /// pointers, or convert structs containing thin pointers to
     /// structs containing fat pointers, or convert between fat
-    /// pointers.  We don't store the details of how the transform is
+    /// pointers. We don't store the details of how the transform is
     /// done (in fact, we don't know that, because it might depend on
     /// the precise type parameters). We just store the target
     /// type. Codegen backends and miri figure out what has to be done
@@ -110,12 +110,12 @@ impl<'a, 'gcx, 'tcx> OverloadedDeref<'tcx> {
 }
 
 /// At least for initial deployment, we want to limit two-phase borrows to
-/// only a few specific cases. Right now, those mostly "things that desugar"
-/// into method calls
-///     - using x.some_method() syntax, where some_method takes &mut self
-///     - using Foo::some_method(&mut x, ...) syntax
-///     - binary assignment operators (+=, -=, *=, etc.)
-/// Anything else should be rejected until generalized two phase borrow support
+/// only a few specific cases. Right now, those are mostly "things that desugar"
+/// into method calls:
+/// - using `x.some_method()` syntax, where some_method takes `&mut self`,
+/// - using `Foo::some_method(&mut x, ...)` syntax,
+/// - binary assignment operators (`+=`, `-=`, `*=`, etc.).
+/// Anything else should be rejected until generalized two-phase borrow support
 /// is implemented. Right now, dataflow can't handle the general case where there
 /// is more than one use of a mutable borrow, and we don't want to accept too much
 /// new code via two-phase borrows, so we try to limit where we create two-phase
@@ -144,10 +144,10 @@ impl From<AutoBorrowMutability> for hir::Mutability {
 
 #[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
 pub enum AutoBorrow<'tcx> {
-    /// Convert from T to &T.
+    /// Converts from T to &T.
     Ref(ty::Region<'tcx>, AutoBorrowMutability),
 
-    /// Convert from T to *T.
+    /// Converts from T to *T.
     RawPtr(hir::Mutability),
 }
 
diff --git a/src/librustc/ty/binding.rs b/src/librustc/ty/binding.rs
index 2ab14642406b1..1290141b0a6b0 100644
--- a/src/librustc/ty/binding.rs
+++ b/src/librustc/ty/binding.rs
@@ -1,6 +1,6 @@
-use hir::BindingAnnotation::*;
-use hir::BindingAnnotation;
-use hir::Mutability;
+use crate::hir::BindingAnnotation::*;
+use crate::hir::BindingAnnotation;
+use crate::hir::Mutability;
 
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum BindingMode {
diff --git a/src/librustc/ty/cast.rs b/src/librustc/ty/cast.rs
index 0f067de3649bf..0b2112f42d595 100644
--- a/src/librustc/ty/cast.rs
+++ b/src/librustc/ty/cast.rs
@@ -1,7 +1,7 @@
 // Helpers for handling cast expressions, used in both
 // typeck and codegen.
 
-use ty::{self, Ty};
+use crate::ty::{self, Ty};
 
 use syntax::ast;
 
diff --git a/src/librustc/ty/codec.rs b/src/librustc/ty/codec.rs
index e0e4d9c362a6c..e93de32f7257b 100644
--- a/src/librustc/ty/codec.rs
+++ b/src/librustc/ty/codec.rs
@@ -6,15 +6,15 @@
 // The functionality in here is shared between persisting to crate metadata and
 // persisting to incr. comp. caches.
 
-use hir::def_id::{DefId, CrateNum};
-use infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
+use crate::hir::def_id::{DefId, CrateNum};
+use crate::infer::canonical::{CanonicalVarInfo, CanonicalVarInfos};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_serialize::{Decodable, Decoder, Encoder, Encodable, opaque};
+use crate::rustc_serialize::{Decodable, Decoder, Encoder, Encodable, opaque};
 use std::hash::Hash;
 use std::intrinsics;
-use ty::{self, Ty, TyCtxt};
-use ty::subst::Substs;
-use mir::interpret::Allocation;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::subst::Substs;
+use crate::mir::interpret::Allocation;
 
 /// The shorthand encoding uses an enum's variant index `usize`
 /// and is offset by this value so it never matches a real variant.
@@ -252,7 +252,7 @@ pub fn decode_lazy_const<'a, 'tcx, D>(decoder: &mut D)
     where D: TyDecoder<'a, 'tcx>,
           'tcx: 'a,
 {
-    Ok(decoder.tcx().intern_lazy_const(Decodable::decode(decoder)?))
+    Ok(decoder.tcx().mk_lazy_const(Decodable::decode(decoder)?))
 }
 
 #[inline]
@@ -283,7 +283,7 @@ macro_rules! implement_ty_decoder {
             use $crate::ty::codec::*;
             use $crate::ty::subst::Substs;
             use $crate::hir::def_id::{CrateNum};
-            use rustc_serialize::{Decoder, SpecializedDecoder};
+            use crate::rustc_serialize::{Decoder, SpecializedDecoder};
             use std::borrow::Cow;
 
             impl<$($typaram ),*> Decoder for $DecoderName<$($typaram),*> {
diff --git a/src/librustc/ty/constness.rs b/src/librustc/ty/constness.rs
index 3741f4051b896..fff5dcf433ed9 100644
--- a/src/librustc/ty/constness.rs
+++ b/src/librustc/ty/constness.rs
@@ -1,9 +1,9 @@
-use ty::query::Providers;
-use hir::def_id::DefId;
-use hir;
-use ty::TyCtxt;
+use crate::ty::query::Providers;
+use crate::hir::def_id::DefId;
+use crate::hir;
+use crate::ty::TyCtxt;
 use syntax_pos::symbol::Symbol;
-use hir::map::blocks::FnLikeNode;
+use crate::hir::map::blocks::FnLikeNode;
 use syntax::attr;
 
 impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
@@ -37,7 +37,7 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         }
     }
 
-    /// Returns true if this function must conform to `min_const_fn`
+    /// Returns `true` if this function must conform to `min_const_fn`
     pub fn is_min_const_fn(self, def_id: DefId) -> bool {
         // Bail out if the signature doesn't contain `const`
         if !self.is_const_fn_raw(def_id) {
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index d69219efbd884..6bb3222512565 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -1,48 +1,48 @@
-//! type context book-keeping
-
-use dep_graph::DepGraph;
-use dep_graph::{DepNode, DepConstructor};
+//! Type context book-keeping.
+
+use crate::dep_graph::DepGraph;
+use crate::dep_graph::{self, DepNode, DepConstructor};
+use crate::session::Session;
+use crate::session::config::{BorrowckMode, OutputFilenames};
+use crate::session::config::CrateType;
+use crate::middle;
+use crate::hir::{TraitCandidate, HirId, ItemKind, ItemLocalId, Node};
+use crate::hir::def::{Def, Export};
+use crate::hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE};
+use crate::hir::map as hir_map;
+use crate::hir::map::DefPathHash;
+use crate::lint::{self, Lint};
+use crate::ich::{StableHashingContext, NodeIdHashingMode};
+use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
+use crate::infer::outlives::free_region_map::FreeRegionMap;
+use crate::middle::cstore::CrateStoreDyn;
+use crate::middle::cstore::EncodedMetadata;
+use crate::middle::lang_items;
+use crate::middle::resolve_lifetime::{self, ObjectLifetimeDefault};
+use crate::middle::stability;
+use crate::mir::{self, Mir, interpret, ProjectionKind};
+use crate::mir::interpret::Allocation;
+use crate::ty::subst::{Kind, Substs, Subst};
+use crate::ty::ReprOptions;
+use crate::traits;
+use crate::traits::{Clause, Clauses, GoalKind, Goal, Goals};
+use crate::ty::{self, Ty, TypeAndMut};
+use crate::ty::{TyS, TyKind, List};
+use crate::ty::{AdtKind, AdtDef, ClosureSubsts, GeneratorSubsts, Region, Const, LazyConst};
+use crate::ty::{PolyFnSig, InferTy, ParamTy, ProjectionTy, ExistentialPredicate, Predicate};
+use crate::ty::RegionKind;
+use crate::ty::{TyVar, TyVid, IntVar, IntVid, FloatVar, FloatVid};
+use crate::ty::TyKind::*;
+use crate::ty::GenericParamDefKind;
+use crate::ty::layout::{LayoutDetails, TargetDataLayout, VariantIdx};
+use crate::ty::query;
+use crate::ty::steal::Steal;
+use crate::ty::subst::{UserSubsts, UnpackedKind};
+use crate::ty::{BoundVar, BindingMode};
+use crate::ty::CanonicalPolyFnSig;
+use crate::util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap};
+use crate::util::nodemap::{FxHashMap, FxHashSet};
 use errors::DiagnosticBuilder;
-use session::Session;
-use session::config::{BorrowckMode, OutputFilenames};
-use session::config::CrateType;
-use middle;
-use hir::{TraitCandidate, HirId, ItemKind, ItemLocalId, Node};
-use hir::def::{Def, Export};
-use hir::def_id::{CrateNum, DefId, DefIndex, LOCAL_CRATE};
-use hir::map as hir_map;
-use hir::map::DefPathHash;
-use lint::{self, Lint};
-use ich::{StableHashingContext, NodeIdHashingMode};
-use infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
-use infer::outlives::free_region_map::FreeRegionMap;
-use middle::cstore::CrateStoreDyn;
-use middle::cstore::EncodedMetadata;
-use middle::lang_items;
-use middle::resolve_lifetime::{self, ObjectLifetimeDefault};
-use middle::stability;
-use mir::{self, Mir, interpret, ProjectionKind};
-use mir::interpret::Allocation;
-use ty::subst::{Kind, Substs, Subst};
-use ty::ReprOptions;
-use traits;
-use traits::{Clause, Clauses, GoalKind, Goal, Goals};
-use ty::{self, Ty, TypeAndMut};
-use ty::{TyS, TyKind, List};
-use ty::{AdtKind, AdtDef, ClosureSubsts, GeneratorSubsts, Region, Const, LazyConst};
-use ty::{PolyFnSig, InferTy, ParamTy, ProjectionTy, ExistentialPredicate, Predicate};
-use ty::RegionKind;
-use ty::{TyVar, TyVid, IntVar, IntVid, FloatVar, FloatVid};
-use ty::TyKind::*;
-use ty::GenericParamDefKind;
-use ty::layout::{LayoutDetails, TargetDataLayout, VariantIdx};
-use ty::query;
-use ty::steal::Steal;
-use ty::subst::{UserSubsts, UnpackedKind};
-use ty::{BoundVar, BindingMode};
-use ty::CanonicalPolyFnSig;
-use util::nodemap::{DefIdMap, DefIdSet, ItemLocalMap};
-use util::nodemap::{FxHashMap, FxHashSet};
 use rustc_data_structures::interner::HashInterner;
 use smallvec::SmallVec;
 use rustc_data_structures::stable_hasher::{HashStable, hash_stable_hashmap,
@@ -73,7 +73,7 @@ use syntax::feature_gate;
 use syntax::symbol::{Symbol, keywords, InternedString};
 use syntax_pos::Span;
 
-use hir;
+use crate::hir;
 
 pub struct AllArenas<'tcx> {
     pub global: WorkerLocal<GlobalArenas<'tcx>>,
@@ -127,6 +127,7 @@ pub struct CtxtInterners<'tcx> {
     goal: InternedSet<'tcx, GoalKind<'tcx>>,
     goal_list: InternedSet<'tcx, List<Goal<'tcx>>>,
     projs: InternedSet<'tcx, List<ProjectionKind<'tcx>>>,
+    lazy_const: InternedSet<'tcx, LazyConst<'tcx>>,
 }
 
 impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
@@ -144,6 +145,7 @@ impl<'gcx: 'tcx, 'tcx> CtxtInterners<'tcx> {
             goal: Default::default(),
             goal_list: Default::default(),
             projs: Default::default(),
+            lazy_const: Default::default(),
         }
     }
 
@@ -315,6 +317,17 @@ impl<'a, V> LocalTableInContextMut<'a, V> {
     }
 }
 
+/// All information necessary to validate and reveal an `impl Trait` or `existential Type`
+#[derive(RustcEncodable, RustcDecodable, Debug)]
+pub struct ResolvedOpaqueTy<'tcx> {
+    /// The revealed type as seen by this function.
+    pub concrete_type: Ty<'tcx>,
+    /// Generic parameters on the opaque type as passed by this function.
+    /// For `existential type Foo<A, B>; fn foo<T, U>() -> Foo<T, U> { .. }` this is `[T, U]`, not
+    /// `[A, B]`
+    pub substs: &'tcx Substs<'tcx>,
+}
+
 #[derive(RustcEncodable, RustcDecodable, Debug)]
 pub struct TypeckTables<'tcx> {
     /// The HirId::owner all ItemLocalIds in this table are relative to.
@@ -330,13 +343,13 @@ pub struct TypeckTables<'tcx> {
     /// belongs, but it may not exist if it's a tuple field (`tuple.0`).
     field_indices: ItemLocalMap<usize>,
 
-    /// Stores the types for various nodes in the AST.  Note that this table
-    /// is not guaranteed to be populated until after typeck.  See
+    /// Stores the types for various nodes in the AST. Note that this table
+    /// is not guaranteed to be populated until after typeck. See
     /// typeck::check::fn_ctxt for details.
     node_types: ItemLocalMap<Ty<'tcx>>,
 
     /// Stores the type parameters which were substituted to obtain the type
-    /// of this node.  This only applies to nodes that refer to entities
+    /// of this node. This only applies to nodes that refer to entities
     /// parameterized by type parameters, such as generic fns, types, or
     /// other items.
     node_substs: ItemLocalMap<&'tcx Substs<'tcx>>,
@@ -350,7 +363,7 @@ pub struct TypeckTables<'tcx> {
     /// canonical substitutions would include only `for<X> { Vec<X> }`.
     ///
     /// See also `AscribeUserType` statement in MIR.
-    user_provided_types: ItemLocalMap<CanonicalUserTypeAnnotation<'tcx>>,
+    user_provided_types: ItemLocalMap<CanonicalUserType<'tcx>>,
 
     /// Stores the canonicalized types provided by the user. See also
     /// `AscribeUserType` statement in MIR.
@@ -411,13 +424,13 @@ pub struct TypeckTables<'tcx> {
     pub tainted_by_errors: bool,
 
     /// Stores the free-region relationships that were deduced from
-    /// its where clauses and parameter types. These are then
+    /// its where-clauses and parameter types. These are then
     /// read-again by borrowck.
     pub free_region_map: FreeRegionMap<'tcx>,
 
     /// All the existential types that are restricted to concrete types
     /// by this function
-    pub concrete_existential_types: FxHashMap<DefId, Ty<'tcx>>,
+    pub concrete_existential_types: FxHashMap<DefId, ResolvedOpaqueTy<'tcx>>,
 
     /// Given the closure ID this map provides the list of UpvarIDs used by it.
     /// The upvarID contains the HIR node ID and it also contains the full path
@@ -493,7 +506,7 @@ impl<'tcx> TypeckTables<'tcx> {
 
     pub fn user_provided_types(
         &self
-    ) -> LocalTableInContext<'_, CanonicalUserTypeAnnotation<'tcx>> {
+    ) -> LocalTableInContext<'_, CanonicalUserType<'tcx>> {
         LocalTableInContext {
             local_id_root: self.local_id_root,
             data: &self.user_provided_types
@@ -502,7 +515,7 @@ impl<'tcx> TypeckTables<'tcx> {
 
     pub fn user_provided_types_mut(
         &mut self
-    ) -> LocalTableInContextMut<'_, CanonicalUserTypeAnnotation<'tcx>> {
+    ) -> LocalTableInContextMut<'_, CanonicalUserType<'tcx>> {
         LocalTableInContextMut {
             local_id_root: self.local_id_root,
             data: &mut self.user_provided_types
@@ -523,17 +536,14 @@ impl<'tcx> TypeckTables<'tcx> {
         }
     }
 
-    pub fn node_id_to_type(&self, id: hir::HirId) -> Ty<'tcx> {
-        self.node_id_to_type_opt(id).unwrap_or_else(||
-            bug!("node_id_to_type: no type for node `{}`",
-                 tls::with(|tcx| {
-                     let id = tcx.hir().hir_to_node_id(id);
-                     tcx.hir().node_to_string(id)
-                 }))
+    pub fn node_type(&self, id: hir::HirId) -> Ty<'tcx> {
+        self.node_type_opt(id).unwrap_or_else(||
+            bug!("node_type: no type for node `{}`",
+                 tls::with(|tcx| tcx.hir().hir_to_string(id)))
         )
     }
 
-    pub fn node_id_to_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
+    pub fn node_type_opt(&self, id: hir::HirId) -> Option<Ty<'tcx>> {
         validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
         self.node_types.get(&id.local_id).cloned()
     }
@@ -558,11 +568,11 @@ impl<'tcx> TypeckTables<'tcx> {
     // Returns the type of a pattern as a monotype. Like @expr_ty, this function
     // doesn't provide type parameter substitutions.
     pub fn pat_ty(&self, pat: &hir::Pat) -> Ty<'tcx> {
-        self.node_id_to_type(pat.hir_id)
+        self.node_type(pat.hir_id)
     }
 
     pub fn pat_ty_opt(&self, pat: &hir::Pat) -> Option<Ty<'tcx>> {
-        self.node_id_to_type_opt(pat.hir_id)
+        self.node_type_opt(pat.hir_id)
     }
 
     // Returns the type of an expression as a monotype.
@@ -576,11 +586,11 @@ impl<'tcx> TypeckTables<'tcx> {
     // ask for the type of "id" in "id(3)", it will return "fn(&isize) -> isize"
     // instead of "fn(ty) -> T with T = isize".
     pub fn expr_ty(&self, expr: &hir::Expr) -> Ty<'tcx> {
-        self.node_id_to_type(expr.hir_id)
+        self.node_type(expr.hir_id)
     }
 
     pub fn expr_ty_opt(&self, expr: &hir::Expr) -> Option<Ty<'tcx>> {
-        self.node_id_to_type_opt(expr.hir_id)
+        self.node_type_opt(expr.hir_id)
     }
 
     pub fn adjustments(&self) -> LocalTableInContext<'_, Vec<ty::adjustment::Adjustment<'tcx>>> {
@@ -800,25 +810,46 @@ impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for TypeckTables<'gcx> {
 
 newtype_index! {
     pub struct UserTypeAnnotationIndex {
-        DEBUG_FORMAT = "UserTypeAnnotation({})",
+        DEBUG_FORMAT = "UserType({})",
         const START_INDEX = 0,
     }
 }
 
 /// Mapping of type annotation indices to canonical user type annotations.
 pub type CanonicalUserTypeAnnotations<'tcx> =
-    IndexVec<UserTypeAnnotationIndex, (Span, CanonicalUserTypeAnnotation<'tcx>)>;
+    IndexVec<UserTypeAnnotationIndex, CanonicalUserTypeAnnotation<'tcx>>;
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+pub struct CanonicalUserTypeAnnotation<'tcx> {
+    pub user_ty: CanonicalUserType<'tcx>,
+    pub span: Span,
+    pub inferred_ty: Ty<'tcx>,
+}
+
+BraceStructTypeFoldableImpl! {
+    impl<'tcx> TypeFoldable<'tcx> for CanonicalUserTypeAnnotation<'tcx> {
+        user_ty, span, inferred_ty
+    }
+}
+
+BraceStructLiftImpl! {
+    impl<'a, 'tcx> Lift<'tcx> for CanonicalUserTypeAnnotation<'a> {
+        type Lifted = CanonicalUserTypeAnnotation<'tcx>;
+        user_ty, span, inferred_ty
+    }
+}
+
 
 /// Canonicalized user type annotation.
-pub type CanonicalUserTypeAnnotation<'gcx> = Canonical<'gcx, UserTypeAnnotation<'gcx>>;
+pub type CanonicalUserType<'gcx> = Canonical<'gcx, UserType<'gcx>>;
 
-impl CanonicalUserTypeAnnotation<'gcx> {
+impl CanonicalUserType<'gcx> {
     /// Returns `true` if this represents a substitution of the form `[?0, ?1, ?2]`,
-    /// i.e. each thing is mapped to a canonical variable with the same index.
+    /// i.e., each thing is mapped to a canonical variable with the same index.
     pub fn is_identity(&self) -> bool {
         match self.value {
-            UserTypeAnnotation::Ty(_) => false,
-            UserTypeAnnotation::TypeOf(_, user_substs) => {
+            UserType::Ty(_) => false,
+            UserType::TypeOf(_, user_substs) => {
                 if user_substs.user_self_ty.is_some() {
                     return false;
                 }
@@ -849,11 +880,11 @@ impl CanonicalUserTypeAnnotation<'gcx> {
     }
 }
 
-/// A user-given type annotation attached to a constant.  These arise
+/// A user-given type annotation attached to a constant. These arise
 /// from constants that are named via paths, like `Foo::<A>::new` and
 /// so forth.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
-pub enum UserTypeAnnotation<'tcx> {
+pub enum UserType<'tcx> {
     Ty(Ty<'tcx>),
 
     /// The canonical type is the result of `type_of(def_id)` with the
@@ -862,17 +893,17 @@ pub enum UserTypeAnnotation<'tcx> {
 }
 
 EnumTypeFoldableImpl! {
-    impl<'tcx> TypeFoldable<'tcx> for UserTypeAnnotation<'tcx> {
-        (UserTypeAnnotation::Ty)(ty),
-        (UserTypeAnnotation::TypeOf)(def, substs),
+    impl<'tcx> TypeFoldable<'tcx> for UserType<'tcx> {
+        (UserType::Ty)(ty),
+        (UserType::TypeOf)(def, substs),
     }
 }
 
 EnumLiftImpl! {
-    impl<'a, 'tcx> Lift<'tcx> for UserTypeAnnotation<'a> {
-        type Lifted = UserTypeAnnotation<'tcx>;
-        (UserTypeAnnotation::Ty)(ty),
-        (UserTypeAnnotation::TypeOf)(def, substs),
+    impl<'a, 'tcx> Lift<'tcx> for UserType<'a> {
+        type Lifted = UserType<'tcx>;
+        (UserType::Ty)(ty),
+        (UserType::TypeOf)(def, substs),
     }
 }
 
@@ -983,6 +1014,9 @@ pub struct GlobalCtxt<'tcx> {
 
     maybe_unused_trait_imports: FxHashSet<DefId>,
     maybe_unused_extern_crates: Vec<(DefId, Span)>,
+    /// A map of glob use to a set of names it actually imports. Currently only
+    /// used in save-analysis.
+    glob_map: FxHashMap<DefId, FxHashSet<ast::Name>>,
     /// Extern prelude entries. The value is `true` if the entry was introduced
     /// via `extern crate` item and not `--extern` option or compiler built-in.
     pub extern_prelude: FxHashMap<ast::Name, bool>,
@@ -1027,7 +1061,7 @@ pub struct GlobalCtxt<'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
-    /// Get the global TyCtxt.
+    /// Gets the global `TyCtxt`.
     #[inline]
     pub fn global_tcx(self) -> TyCtxt<'gcx, 'gcx, 'gcx> {
         TyCtxt {
@@ -1072,10 +1106,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.global_arenas.adt_def.alloc(def)
     }
 
-    pub fn intern_const_alloc(
-        self,
-        alloc: Allocation,
-    ) -> &'gcx Allocation {
+    pub fn intern_const_alloc(self, alloc: Allocation) -> &'gcx Allocation {
         self.allocation_interner.borrow_mut().intern(alloc, |alloc| {
             self.global_arenas.const_allocs.alloc(alloc)
         })
@@ -1095,10 +1126,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         })
     }
 
-    pub fn intern_lazy_const(self, c: ty::LazyConst<'tcx>) -> &'tcx ty::LazyConst<'tcx> {
-        self.global_interners.arena.alloc(c)
-    }
-
     pub fn intern_layout(self, layout: LayoutDetails) -> &'gcx LayoutDetails {
         self.layout_interner.borrow_mut().intern(layout, |layout| {
             self.global_arenas.layout.alloc(layout)
@@ -1134,12 +1161,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         value.lift_to_tcx(self.global_tcx())
     }
 
-    /// Returns true if self is the same as self.global_tcx().
+    /// Returns `true` if self is the same as self.global_tcx().
     fn is_global(self) -> bool {
         ptr::eq(self.interners, &self.global_interners)
     }
 
-    /// Create a type context and call the closure with a `TyCtxt` reference
+    /// Creates a type context and call the closure with a `TyCtxt` reference
     /// to the context. The closure enforces that the type context and any interned
     /// value (types, substs, etc.) can only be used while `ty::tls` has a valid
     /// reference to the context, to allow formatting values that need it.
@@ -1232,6 +1259,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                     .into_iter()
                     .map(|(id, sp)| (hir.local_def_id(id), sp))
                     .collect(),
+            glob_map: resolutions.glob_map.into_iter().map(|(id, names)| {
+                (hir.local_def_id(id), names)
+            }).collect(),
             extern_prelude: resolutions.extern_prelude,
             hir_map: hir,
             def_path_hash_to_def_id,
@@ -1331,7 +1361,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Convert a `DefId` into its fully expanded `DefPath` (every
+    /// Converts a `DefId` into its fully expanded `DefPath` (every
     /// `DefId` is really just an interned def-path).
     ///
     /// Note that if `id` is not local to this crate, the result will
@@ -1408,7 +1438,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             self.dep_graph.with_task(dep_node,
                                      self,
                                      crate_hash,
-                                     |_, x| x // No transformation needed
+                                     |_, x| x, // No transformation needed
+                                     dep_graph::hash_result,
             );
         }
     }
@@ -1648,6 +1679,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
         false
     }
+
+    /// Determine whether identifiers in the assembly have strict naming rules.
+    /// Currently, only NVPTX* targets need it.
+    pub fn has_strict_asm_symbol_naming(&self) -> bool {
+        self.gcx.sess.target.target.arch.contains("nvptx")
+    }
 }
 
 impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
@@ -1740,7 +1777,7 @@ macro_rules! nop_list_lift {
         impl<'a, 'tcx> Lift<'tcx> for &'a List<$ty> {
             type Lifted = &'tcx List<$lifted>;
             fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-                        if self.is_empty() {
+                if self.is_empty() {
                     return Some(List::empty());
                 }
                 if tcx.interners.arena.in_arena(*self as *const _) {
@@ -1789,18 +1826,18 @@ pub mod tls {
     use std::marker::PhantomData;
     use std::ptr;
     use syntax_pos;
-    use ty::query;
+    use crate::ty::query;
     use errors::{Diagnostic, TRACK_DIAGNOSTICS};
     use rustc_data_structures::OnDrop;
     use rustc_data_structures::sync::{self, Lrc, Lock};
     use rustc_data_structures::thin_vec::ThinVec;
-    use dep_graph::TaskDeps;
+    use crate::dep_graph::TaskDeps;
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     use std::cell::Cell;
 
-    #[cfg(parallel_queries)]
-    use rayon_core;
+    #[cfg(parallel_compiler)]
+    use rustc_rayon_core as rayon_core;
 
     /// This is the implicit state of rustc. It contains the current
     /// TyCtxt and query. It is updated when creating a local interner or
@@ -1832,7 +1869,7 @@ pub mod tls {
     /// Sets Rayon's thread local variable which is preserved for Rayon jobs
     /// to `value` during the call to `f`. It is restored to its previous value after.
     /// This is used to set the pointer to the new ImplicitCtxt.
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline]
     fn set_tlv<F: FnOnce() -> R, R>(value: usize, f: F) -> R {
         rayon_core::tlv::with(value, f)
@@ -1840,20 +1877,20 @@ pub mod tls {
 
     /// Gets Rayon's thread local variable which is preserved for Rayon jobs.
     /// This is used to get the pointer to the current ImplicitCtxt.
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline]
     fn get_tlv() -> usize {
         rayon_core::tlv::get()
     }
 
     /// A thread local variable which stores a pointer to the current ImplicitCtxt
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     thread_local!(static TLV: Cell<usize> = Cell::new(0));
 
     /// Sets TLV to `value` during the call to `f`.
     /// It is restored to its previous value after.
     /// This is used to set the pointer to the new ImplicitCtxt.
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline]
     fn set_tlv<F: FnOnce() -> R, R>(value: usize, f: F) -> R {
         let old = get_tlv();
@@ -1863,7 +1900,7 @@ pub mod tls {
     }
 
     /// This is used to get the pointer to the current ImplicitCtxt.
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     fn get_tlv() -> usize {
         TLV.with(|tlv| tlv.get())
     }
@@ -2081,8 +2118,8 @@ macro_rules! sty_debug_print {
         // variable names.
         #[allow(non_snake_case)]
         mod inner {
-            use ty::{self, TyCtxt};
-            use ty::context::Interned;
+            use crate::ty::{self, TyCtxt};
+            use crate::ty::context::Interned;
 
             #[derive(Copy, Clone)]
             struct DebugStat {
@@ -2238,6 +2275,12 @@ impl<'tcx: 'lcx, 'lcx> Borrow<GoalKind<'lcx>> for Interned<'tcx, GoalKind<'tcx>>
     }
 }
 
+impl<'tcx: 'lcx, 'lcx> Borrow<LazyConst<'lcx>> for Interned<'tcx, LazyConst<'tcx>> {
+    fn borrow<'a>(&'a self) -> &'a LazyConst<'lcx> {
+        &self.0
+    }
+}
+
 impl<'tcx: 'lcx, 'lcx> Borrow<[ExistentialPredicate<'lcx>]>
     for Interned<'tcx, List<ExistentialPredicate<'tcx>>> {
     fn borrow<'a>(&'a self) -> &'a [ExistentialPredicate<'lcx>] {
@@ -2344,7 +2387,8 @@ pub fn keep_local<'tcx, T: ty::TypeFoldable<'tcx>>(x: &T) -> bool {
 
 direct_interners!('tcx,
     region: mk_region(|r: &RegionKind| r.keep_in_local_tcx()) -> RegionKind,
-    goal: mk_goal(|c: &GoalKind<'_>| keep_local(c)) -> GoalKind<'tcx>
+    goal: mk_goal(|c: &GoalKind<'_>| keep_local(c)) -> GoalKind<'tcx>,
+    lazy_const: mk_lazy_const(|c: &LazyConst<'_>| keep_local(&c)) -> LazyConst<'tcx>
 );
 
 macro_rules! slice_interners {
@@ -2529,7 +2573,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     #[inline]
     pub fn mk_array(self, ty: Ty<'tcx>, n: u64) -> Ty<'tcx> {
-        self.mk_ty(Array(ty, self.intern_lazy_const(
+        self.mk_ty(Array(ty, self.mk_lazy_const(
             ty::LazyConst::Evaluated(ty::Const::from_usize(self.global_tcx(), n))
         )))
     }
@@ -2972,6 +3016,10 @@ pub fn provide(providers: &mut ty::query::Providers<'_>) {
         assert_eq!(cnum, LOCAL_CRATE);
         Lrc::new(tcx.maybe_unused_extern_crates.clone())
     };
+    providers.names_imported_by_glob_use = |tcx, id| {
+        assert_eq!(id.krate, LOCAL_CRATE);
+        Lrc::new(tcx.glob_map.get(&id).cloned().unwrap_or_default())
+    };
 
     providers.stability_index = |tcx, cnum| {
         assert_eq!(cnum, LOCAL_CRATE);
diff --git a/src/librustc/ty/erase_regions.rs b/src/librustc/ty/erase_regions.rs
index bbf71c62ca69d..0431afcc76c9e 100644
--- a/src/librustc/ty/erase_regions.rs
+++ b/src/librustc/ty/erase_regions.rs
@@ -1,5 +1,5 @@
-use ty::{self, Ty, TyCtxt};
-use ty::fold::{TypeFolder, TypeFoldable};
+use crate::ty::{self, Ty, TyCtxt, TypeFlags};
+use crate::ty::fold::{TypeFolder, TypeFoldable};
 
 pub(super) fn provide(providers: &mut ty::query::Providers<'_>) {
     *providers = ty::query::Providers {
@@ -21,6 +21,11 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     pub fn erase_regions<T>(self, value: &T) -> T
         where T : TypeFoldable<'tcx>
     {
+        // If there's nothing to erase avoid performing the query at all
+        if !value.has_type_flags(TypeFlags::HAS_RE_LATE_BOUND | TypeFlags::HAS_FREE_REGIONS) {
+            return value.clone();
+        }
+
         let value1 = value.fold_with(&mut RegionEraserVisitor { tcx: self });
         debug!("erase_regions({:?}) = {:?}", value, value1);
         value1
diff --git a/src/librustc/ty/error.rs b/src/librustc/ty/error.rs
index 834b541d4c01b..f58e5e4fb69f6 100644
--- a/src/librustc/ty/error.rs
+++ b/src/librustc/ty/error.rs
@@ -1,5 +1,5 @@
-use hir::def_id::DefId;
-use ty::{self, Region, Ty, TyCtxt};
+use crate::hir::def_id::DefId;
+use crate::ty::{self, BoundRegion, Region, Ty, TyCtxt};
 use std::borrow::Cow;
 use std::fmt;
 use rustc_target::spec::abi;
@@ -7,7 +7,7 @@ use syntax::ast;
 use errors::{Applicability, DiagnosticBuilder};
 use syntax_pos::Span;
 
-use hir;
+use crate::hir;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct ExpectedFound<T> {
@@ -27,6 +27,8 @@ pub enum TypeError<'tcx> {
     ArgCount,
 
     RegionsDoesNotOutlive(Region<'tcx>, Region<'tcx>),
+    RegionsInsufficientlyPolymorphic(BoundRegion, Region<'tcx>),
+    RegionsOverlyPolymorphic(BoundRegion, Region<'tcx>),
     RegionsPlaceholderMismatch,
 
     Sorts(ExpectedFound<Ty<'tcx>>),
@@ -101,6 +103,18 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
             RegionsDoesNotOutlive(..) => {
                 write!(f, "lifetime mismatch")
             }
+            RegionsInsufficientlyPolymorphic(br, _) => {
+                write!(f,
+                       "expected bound lifetime parameter{}{}, found concrete lifetime",
+                       if br.is_named() { " " } else { "" },
+                       br)
+            }
+            RegionsOverlyPolymorphic(br, _) => {
+                write!(f,
+                       "expected concrete lifetime, found bound lifetime parameter{}{}",
+                       if br.is_named() { " " } else { "" },
+                       br)
+            }
             RegionsPlaceholderMismatch => {
                 write!(f, "one type is more general than the other")
             }
@@ -237,7 +251,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 {
                     if let Ok(snippet) = self.sess.source_map().span_to_snippet(sp) {
                         if snippet.chars().all(|c| c.is_digit(10) || c == '-' || c == '_') {
-                            db.span_suggestion_with_applicability(
+                            db.span_suggestion(
                                 sp,
                                 "use a float literal",
                                 format!("{}.0", snippet),
diff --git a/src/librustc/ty/fast_reject.rs b/src/librustc/ty/fast_reject.rs
index 2b41fc4fe341f..59ab4561f2c87 100644
--- a/src/librustc/ty/fast_reject.rs
+++ b/src/librustc/ty/fast_reject.rs
@@ -1,12 +1,12 @@
-use hir::def_id::DefId;
-use ich::StableHashingContext;
+use crate::hir::def_id::DefId;
+use crate::ich::StableHashingContext;
 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
                                            HashStable};
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::mem;
 use syntax::ast;
-use ty::{self, Ty, TyCtxt};
+use crate::ty::{self, Ty, TyCtxt};
 
 use self::SimplifiedTypeGen::*;
 
diff --git a/src/librustc/ty/flags.rs b/src/librustc/ty/flags.rs
index 4fa13a01d5a92..25ec3e49cdf67 100644
--- a/src/librustc/ty/flags.rs
+++ b/src/librustc/ty/flags.rs
@@ -1,5 +1,5 @@
-use ty::subst::Substs;
-use ty::{self, Ty, TypeFlags, TypeFoldable};
+use crate::ty::subst::Substs;
+use crate::ty::{self, Ty, TypeFlags, TypeFoldable};
 
 #[derive(Debug)]
 pub struct FlagComputation {
diff --git a/src/librustc/ty/fold.rs b/src/librustc/ty/fold.rs
index 28b6f010ce09c..aa4d1e5ea90cb 100644
--- a/src/librustc/ty/fold.rs
+++ b/src/librustc/ty/fold.rs
@@ -4,7 +4,7 @@
 //! instance of a "folder" (a type which implements `TypeFolder`). Then
 //! the setup is intended to be:
 //!
-//!   T.fold_with(F) --calls--> F.fold_T(T) --calls--> T.super_fold_with(F)
+//!     T.fold_with(F) --calls--> F.fold_T(T) --calls--> T.super_fold_with(F)
 //!
 //! This way, when you define a new folder F, you can override
 //! `fold_T()` to customize the behavior, and invoke `T.super_fold_with()`
@@ -25,16 +25,18 @@
 //! proper thing.
 //!
 //! A `TypeFoldable` T can also be visited by a `TypeVisitor` V using similar setup:
-//!   T.visit_with(V) --calls--> V.visit_T(T) --calls--> T.super_visit_with(V).
-//! These methods return true to indicate that the visitor has found what it is looking for
-//! and does not need to visit anything else.
+//!
+//!     T.visit_with(V) --calls--> V.visit_T(T) --calls--> T.super_visit_with(V).
+//!
+//! These methods return true to indicate that the visitor has found what it is
+//! looking for, and does not need to visit anything else.
 
-use hir::def_id::DefId;
-use ty::{self, Binder, Ty, TyCtxt, TypeFlags};
+use crate::hir::def_id::DefId;
+use crate::ty::{self, Binder, Ty, TyCtxt, TypeFlags};
 
 use std::collections::BTreeMap;
 use std::fmt;
-use util::nodemap::FxHashSet;
+use crate::util::nodemap::FxHashSet;
 
 /// The TypeFoldable trait is implemented for every type that can be folded.
 /// Basically, every type that has a corresponding method in TypeFolder.
@@ -52,7 +54,7 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
         self.super_visit_with(visitor)
     }
 
-    /// True if `self` has any late-bound regions that are either
+    /// Returns `true` if `self` has any late-bound regions that are either
     /// bound by `binder` or bound by some binder outside of `binder`.
     /// If `binder` is `ty::INNERMOST`, this indicates whether
     /// there are any late-bound regions that appear free.
@@ -60,7 +62,7 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
         self.visit_with(&mut HasEscapingVarsVisitor { outer_index: binder })
     }
 
-    /// True if this `self` has any regions that escape `binder` (and
+    /// Returns `true` if this `self` has any regions that escape `binder` (and
     /// hence are not bound by it).
     fn has_vars_bound_above(&self, binder: ty::DebruijnIndex) -> bool {
         self.has_vars_bound_at_or_above(binder.shifted_in(1))
@@ -141,7 +143,7 @@ pub trait TypeFoldable<'tcx>: fmt::Debug + Clone {
     }
 }
 
-/// The TypeFolder trait defines the actual *folding*. There is a
+/// The `TypeFolder` trait defines the actual *folding*. There is a
 /// method defined for every foldable type. Each of these has a
 /// default implementation that does an "identity" fold. Within each
 /// identity fold, it should invoke `foo.fold_with(self)` to fold each
@@ -262,7 +264,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         });
     }
 
-    /// True if `callback` returns true for every region appearing free in `value`.
+    /// Returns `true` if `callback` returns true for every region appearing free in `value`.
     pub fn all_free_regions_meet(
         self,
         value: &impl TypeFoldable<'tcx>,
@@ -271,7 +273,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         !self.any_free_region_meets(value, |r| !callback(r))
     }
 
-    /// True if `callback` returns true for some region appearing free in `value`.
+    /// Returns `true` if `callback` returns true for some region appearing free in `value`.
     pub fn any_free_region_meets(
         self,
         value: &impl TypeFoldable<'tcx>,
@@ -292,8 +294,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             /// ^          ^          ^     ^
             /// |          |          |     | here, would be shifted in 1
             /// |          |          | here, would be shifted in 2
-            /// |          | here, would be INNERMOST shifted in by 1
-            /// | here, initially, binder would be INNERMOST
+            /// |          | here, would be `INNERMOST` shifted in by 1
+            /// | here, initially, binder would be `INNERMOST`
             /// ```
             ///
             /// You see that, initially, *any* bound value is free,
@@ -496,12 +498,12 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for BoundVarReplacer<'a, 'gcx, 'tcx>
 }
 
 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
-    /// Replace all regions bound by the given `Binder` with the
+    /// Replaces all regions bound by the given `Binder` with the
     /// results returned by the closure; the closure is expected to
     /// return a free region (relative to this binder), and hence the
     /// binder is removed in the return type. The closure is invoked
     /// once for each unique `BoundRegion`; multiple references to the
-    /// same `BoundRegion` will reuse the previous result.  A map is
+    /// same `BoundRegion` will reuse the previous result. A map is
     /// returned at the end with each bound region and the free region
     /// that replaced it.
     ///
@@ -520,7 +522,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.replace_escaping_bound_vars(value.skip_binder(), fld_r, fld_t)
     }
 
-    /// Replace all escaping bound vars. The `fld_r` closure replaces escaping
+    /// Replaces all escaping bound vars. The `fld_r` closure replaces escaping
     /// bound regions while the `fld_t` closure replaces escaping bound types.
     pub fn replace_escaping_bound_vars<T, F, G>(
         self,
@@ -554,7 +556,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Replace all types or regions bound by the given `Binder`. The `fld_r`
+    /// Replaces all types or regions bound by the given `Binder`. The `fld_r`
     /// closure replaces bound regions while the `fld_t` closure replaces bound
     /// types.
     pub fn replace_bound_vars<T, F, G>(
@@ -570,7 +572,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.replace_escaping_bound_vars(value.skip_binder(), fld_r, fld_t)
     }
 
-    /// Replace any late-bound regions bound in `value` with
+    /// Replaces any late-bound regions bound in `value` with
     /// free variants attached to `all_outlive_scope`.
     pub fn liberate_late_bound_regions<T>(
         &self,
@@ -586,31 +588,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }).0
     }
 
-    /// Flattens multiple binding levels into one. So `for<'a> for<'b> Foo`
-    /// becomes `for<'a,'b> Foo`.
-    pub fn flatten_late_bound_regions<T>(self, bound2_value: &Binder<Binder<T>>)
-                                         -> Binder<T>
-        where T: TypeFoldable<'tcx>
-    {
-        let bound0_value = bound2_value.skip_binder().skip_binder();
-        let value = self.fold_regions(bound0_value, &mut false, |region, current_depth| {
-            match *region {
-                ty::ReLateBound(debruijn, br) => {
-                    // We assume no regions bound *outside* of the
-                    // binders in `bound2_value` (nmatsakis added in
-                    // the course of this PR; seems like a reasonable
-                    // sanity check though).
-                    assert!(debruijn == current_depth);
-                    self.mk_region(ty::ReLateBound(current_depth, br))
-                }
-                _ => {
-                    region
-                }
-            }
-        });
-        Binder::bind(value)
-    }
-
     /// Returns a set of all late-bound regions that are constrained
     /// by `value`, meaning that if we instantiate those LBR with
     /// variables and equate `value` with something else, those
@@ -640,7 +617,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         collector.regions
     }
 
-    /// Replace any late-bound regions bound in `value` with `'erased`. Useful in codegen but also
+    /// Replaces any late-bound regions bound in `value` with `'erased`. Useful in codegen but also
     /// method lookup and a few other places where precise region relationships are not required.
     pub fn erase_late_bound_regions<T>(self, value: &Binder<T>) -> T
         where T : TypeFoldable<'tcx>
@@ -648,13 +625,13 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.replace_late_bound_regions(value, |_| self.types.re_erased).0
     }
 
-    /// Rewrite any late-bound regions so that they are anonymous.  Region numbers are
+    /// Rewrite any late-bound regions so that they are anonymous. Region numbers are
     /// assigned starting at 1 and increasing monotonically in the order traversed
     /// by the fold operation.
     ///
     /// The chief purpose of this function is to canonicalize regions so that two
     /// `FnSig`s or `TraitRef`s which are equivalent up to region naming will become
-    /// structurally identical.  For example, `for<'a, 'b> fn(&'a isize, &'b isize)` and
+    /// structurally identical. For example, `for<'a, 'b> fn(&'a isize, &'b isize)` and
     /// `for<'a, 'b> fn(&'b isize, &'a isize)` will become identical after anonymization.
     pub fn anonymize_late_bound_regions<T>(self, sig: &Binder<T>) -> Binder<T>
         where T : TypeFoldable<'tcx>,
@@ -818,7 +795,7 @@ pub fn shift_out_vars<'a, 'gcx, 'tcx, T>(
 /// scope to which it is attached, etc. An escaping var represents
 /// a bound var for which this processing has not yet been done.
 struct HasEscapingVarsVisitor {
-    /// Anything bound by `outer_index` or "above" is escaping
+    /// Anything bound by `outer_index` or "above" is escaping.
     outer_index: ty::DebruijnIndex,
 }
 
@@ -881,10 +858,10 @@ struct LateBoundRegionsCollector {
     current_index: ty::DebruijnIndex,
     regions: FxHashSet<ty::BoundRegion>,
 
-    /// If true, we only want regions that are known to be
+    /// `true` if we only want regions that are known to be
     /// "constrained" when you equate this type with another type. In
     /// particular, if you have e.g., `&'a u32` and `&'b u32`, equating
-    /// them constraints `'a == 'b`.  But if you have `<&'a u32 as
+    /// them constraints `'a == 'b`. But if you have `<&'a u32 as
     /// Trait>::Foo` and `<&'b u32 as Trait>::Foo`, normalizing those
     /// types may mean that `'a` and `'b` don't appear in the results,
     /// so they are not considered *constrained*.
diff --git a/src/librustc/ty/inhabitedness/def_id_forest.rs b/src/librustc/ty/inhabitedness/def_id_forest.rs
index 41fd88607e893..3b393c3ca15bb 100644
--- a/src/librustc/ty/inhabitedness/def_id_forest.rs
+++ b/src/librustc/ty/inhabitedness/def_id_forest.rs
@@ -1,8 +1,8 @@
 use std::mem;
 use smallvec::SmallVec;
 use syntax::ast::CRATE_NODE_ID;
-use ty::context::TyCtxt;
-use ty::{DefId, DefIdTree};
+use crate::ty::context::TyCtxt;
+use crate::ty::{DefId, DefIdTree};
 
 /// Represents a forest of DefIds closed under the ancestor relation. That is,
 /// if a DefId representing a module is contained in the forest then all
@@ -22,14 +22,14 @@ pub struct DefIdForest {
 }
 
 impl<'a, 'gcx, 'tcx> DefIdForest {
-    /// Create an empty forest.
+    /// Creates an empty forest.
     pub fn empty() -> DefIdForest {
         DefIdForest {
             root_ids: SmallVec::new(),
         }
     }
 
-    /// Create a forest consisting of a single tree representing the entire
+    /// Creates a forest consisting of a single tree representing the entire
     /// crate.
     #[inline]
     pub fn full(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> DefIdForest {
@@ -37,7 +37,7 @@ impl<'a, 'gcx, 'tcx> DefIdForest {
         DefIdForest::from_id(crate_id)
     }
 
-    /// Create a forest containing a DefId and all its descendants.
+    /// Creates a forest containing a DefId and all its descendants.
     pub fn from_id(id: DefId) -> DefIdForest {
         let mut root_ids = SmallVec::new();
         root_ids.push(id);
@@ -46,12 +46,12 @@ impl<'a, 'gcx, 'tcx> DefIdForest {
         }
     }
 
-    /// Test whether the forest is empty.
+    /// Tests whether the forest is empty.
     pub fn is_empty(&self) -> bool {
         self.root_ids.is_empty()
     }
 
-    /// Test whether the forest contains a given DefId.
+    /// Tests whether the forest contains a given DefId.
     pub fn contains(&self,
                     tcx: TyCtxt<'a, 'gcx, 'tcx>,
                     id: DefId) -> bool
diff --git a/src/librustc/ty/inhabitedness/mod.rs b/src/librustc/ty/inhabitedness/mod.rs
index 6dfc9681cfd86..601ffe70eec18 100644
--- a/src/librustc/ty/inhabitedness/mod.rs
+++ b/src/librustc/ty/inhabitedness/mod.rs
@@ -1,8 +1,8 @@
-use ty::context::TyCtxt;
-use ty::{AdtDef, VariantDef, FieldDef, Ty, TyS};
-use ty::{self, DefId, Substs};
-use ty::{AdtKind, Visibility};
-use ty::TyKind::*;
+use crate::ty::context::TyCtxt;
+use crate::ty::{AdtDef, VariantDef, FieldDef, Ty, TyS};
+use crate::ty::{self, DefId, Substs};
+use crate::ty::{AdtKind, Visibility};
+use crate::ty::TyKind::*;
 
 pub use self::def_id_forest::DefIdForest;
 
diff --git a/src/librustc/ty/instance.rs b/src/librustc/ty/instance.rs
index 78b6ffaa54e17..5fc22e3c02b60 100644
--- a/src/librustc/ty/instance.rs
+++ b/src/librustc/ty/instance.rs
@@ -1,9 +1,9 @@
-use hir::Unsafety;
-use hir::def_id::DefId;
-use ty::{self, Ty, PolyFnSig, TypeFoldable, Substs, TyCtxt};
-use traits;
+use crate::hir::Unsafety;
+use crate::hir::def_id::DefId;
+use crate::ty::{self, Ty, PolyFnSig, TypeFoldable, Substs, TyCtxt};
+use crate::traits;
 use rustc_target::spec::abi::Abi;
-use util::ppaux;
+use crate::util::ppaux;
 
 use std::fmt;
 use std::iter;
@@ -22,17 +22,17 @@ pub enum InstanceDef<'tcx> {
     /// `<T as Trait>::method` where `method` receives unsizeable `self: Self`.
     VtableShim(DefId),
 
-    /// \<fn() as FnTrait>::call_*
-    /// def-id is FnTrait::call_*
+    /// `<fn() as FnTrait>::call_*`
+    /// `DefId` is `FnTrait::call_*`
     FnPtrShim(DefId, Ty<'tcx>),
 
-    /// <Trait as Trait>::fn
+    /// `<Trait as Trait>::fn`
     Virtual(DefId, usize),
 
-    /// <[mut closure] as FnOnce>::call_once
+    /// `<[mut closure] as FnOnce>::call_once`
     ClosureOnceShim { call_once: DefId },
 
-    /// drop_in_place::<T>; None for empty drop glue.
+    /// `drop_in_place::<T>; None` for empty drop glue.
     DropGlue(DefId, Option<Ty<'tcx>>),
 
     ///`<T as Clone>::clone` shim.
@@ -76,6 +76,11 @@ impl<'a, 'tcx> Instance<'tcx> {
                 let env_region = ty::ReLateBound(ty::INNERMOST, ty::BrEnv);
                 let env_ty = tcx.mk_mut_ref(tcx.mk_region(env_region), ty);
 
+                let pin_did = tcx.lang_items().pin_type().unwrap();
+                let pin_adt_ref = tcx.adt_def(pin_did);
+                let pin_substs = tcx.intern_substs(&[env_ty.into()]);
+                let env_ty = tcx.mk_adt(pin_adt_ref, pin_substs);
+
                 sig.map_bound(|sig| {
                     let state_did = tcx.lang_items().gen_state().unwrap();
                     let state_adt_ref = tcx.adt_def(state_did);
@@ -136,7 +141,7 @@ impl<'tcx> InstanceDef<'tcx> {
         &self,
         tcx: TyCtxt<'a, 'tcx, 'tcx>
     ) -> bool {
-        use hir::map::DefPathData;
+        use crate::hir::map::DefPathData;
         let def_id = match *self {
             ty::InstanceDef::Item(def_id) => def_id,
             ty::InstanceDef::DropGlue(_, Some(_)) => return false,
@@ -215,7 +220,7 @@ impl<'a, 'b, 'tcx> Instance<'tcx> {
         self.def.def_id()
     }
 
-    /// Resolve a (def_id, substs) pair to an (optional) instance -- most commonly,
+    /// Resolves a `(def_id, substs)` pair to an (optional) instance -- most commonly,
     /// this is used to find the precise code that will run for a trait method invocation,
     /// if known.
     ///
diff --git a/src/librustc/ty/item_path.rs b/src/librustc/ty/item_path.rs
index 417e14054d24f..26e2705a7a034 100644
--- a/src/librustc/ty/item_path.rs
+++ b/src/librustc/ty/item_path.rs
@@ -1,7 +1,7 @@
-use hir::map::DefPathData;
-use hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
-use ty::{self, DefIdTree, Ty, TyCtxt};
-use middle::cstore::{ExternCrate, ExternCrateSource};
+use crate::hir::map::DefPathData;
+use crate::hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use crate::ty::{self, DefIdTree, Ty, TyCtxt};
+use crate::middle::cstore::{ExternCrate, ExternCrateSource};
 use syntax::ast;
 use syntax::symbol::{keywords, LocalInternedString, Symbol};
 
@@ -42,7 +42,7 @@ pub fn with_forced_impl_filename_line<F: FnOnce() -> R, R>(f: F) -> R {
     })
 }
 
-/// Add the `crate::` prefix to paths where appropriate.
+/// Adds the `crate::` prefix to paths where appropriate.
 pub fn with_crate_prefix<F: FnOnce() -> R, R>(f: F) -> R {
     SHOULD_PREFIX_WITH_CRATE.with(|flag| {
         let old = flag.get();
@@ -54,7 +54,7 @@ pub fn with_crate_prefix<F: FnOnce() -> R, R>(f: F) -> R {
 }
 
 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
-    /// Returns a string identifying this def-id. This string is
+    /// Returns a string identifying this `DefId`. This string is
     /// suitable for user output. It is relative to the current crate
     /// root, unless with_forced_absolute_paths was used.
     pub fn item_path_str(self, def_id: DefId) -> String {
@@ -210,12 +210,12 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
             let visible_parent = visible_parent_map.get(&cur_def).cloned();
             let actual_parent = self.parent(cur_def);
-            debug!(
-                "try_push_visible_item_path: visible_parent={:?} actual_parent={:?}",
-                visible_parent, actual_parent,
-            );
 
             let data = cur_def_key.disambiguated_data.data;
+            debug!(
+                "try_push_visible_item_path: data={:?} visible_parent={:?} actual_parent={:?}",
+                data, visible_parent, actual_parent,
+            );
             let symbol = match data {
                 // In order to output a path that could actually be imported (valid and visible),
                 // we need to handle re-exports correctly.
@@ -248,16 +248,16 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 // the children of the visible parent (as was done when computing
                 // `visible_parent_map`), looking for the specific child we currently have and then
                 // have access to the re-exported name.
-                DefPathData::Module(module_name) if visible_parent != actual_parent => {
-                    let mut name: Option<ast::Ident> = None;
-                    if let Some(visible_parent) = visible_parent {
-                        for child in self.item_children(visible_parent).iter() {
-                            if child.def.def_id() == cur_def {
-                                name = Some(child.ident);
-                            }
-                        }
-                    }
-                    name.map(|n| n.as_str()).unwrap_or(module_name.as_str())
+                DefPathData::Module(actual_name) |
+                DefPathData::TypeNs(actual_name) if visible_parent != actual_parent => {
+                    visible_parent
+                        .and_then(|parent| {
+                            self.item_children(parent)
+                                .iter()
+                                .find(|child| child.def.def_id() == cur_def)
+                                .map(|child| child.ident.as_str())
+                        })
+                        .unwrap_or_else(|| actual_name.as_str())
                 },
                 _ => {
                     data.get_opt_name().map(|n| n.as_str()).unwrap_or_else(|| {
@@ -311,6 +311,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             data @ DefPathData::Misc |
             data @ DefPathData::TypeNs(..) |
             data @ DefPathData::Trait(..) |
+            data @ DefPathData::TraitAlias(..) |
             data @ DefPathData::AssocTypeInTrait(..) |
             data @ DefPathData::AssocTypeInImpl(..) |
             data @ DefPathData::AssocExistentialInImpl(..) |
@@ -318,6 +319,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             data @ DefPathData::Module(..) |
             data @ DefPathData::TypeParam(..) |
             data @ DefPathData::LifetimeParam(..) |
+            data @ DefPathData::ConstParam(..) |
             data @ DefPathData::EnumVariant(..) |
             data @ DefPathData::Field(..) |
             data @ DefPathData::AnonConst |
@@ -454,13 +456,13 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // only occur very early in the compiler pipeline.
         let parent_def_id = self.parent_def_id(impl_def_id).unwrap();
         self.push_item_path(buffer, parent_def_id, pushed_prelude_crate);
-        let node_id = self.hir().as_local_node_id(impl_def_id).unwrap();
-        let item = self.hir().expect_item(node_id);
+        let hir_id = self.hir().as_local_hir_id(impl_def_id).unwrap();
+        let item = self.hir().expect_item_by_hir_id(hir_id);
         let span_str = self.sess.source_map().span_to_string(item.span);
         buffer.push(&format!("<impl at {}>", span_str));
     }
 
-    /// Returns the def-id of `def_id`'s parent in the def tree. If
+    /// Returns the `DefId` of `def_id`'s parent in the def tree. If
     /// this returns `None`, then `def_id` represents a crate root or
     /// inlined root.
     pub fn parent_def_id(self, def_id: DefId) -> Option<DefId> {
@@ -470,9 +472,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 }
 
 /// As a heuristic, when we see an impl, if we see that the
-/// 'self-type' is a type defined in the same module as the impl,
+/// 'self type' is a type defined in the same module as the impl,
 /// we can omit including the path to the impl itself. This
-/// function tries to find a "characteristic def-id" for a
+/// function tries to find a "characteristic `DefId`" for a
 /// type. It's just a heuristic so it makes some questionable
 /// decisions and we may want to adjust it later.
 pub fn characteristic_def_id_of_type(ty: Ty<'_>) -> Option<DefId> {
@@ -527,7 +529,7 @@ pub trait ItemPathBuffer {
 
 #[derive(Debug)]
 pub enum RootMode {
-    /// Try to make a path relative to the local crate.  In
+    /// Try to make a path relative to the local crate. In
     /// particular, local paths have no prefix, and if the path comes
     /// from an extern crate, start with the path to the `extern
     /// crate` declaration.
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 1162bff852cbb..6c507c0015d7b 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -1,5 +1,5 @@
-use session::{self, DataTypeKind};
-use ty::{self, Ty, TyCtxt, TypeFoldable, ReprOptions};
+use crate::session::{self, DataTypeKind};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable, ReprOptions};
 
 use syntax::ast::{self, Ident, IntTy, UintTy};
 use syntax::attr;
@@ -12,7 +12,7 @@ use std::iter;
 use std::mem;
 use std::ops::Bound;
 
-use ich::StableHashingContext;
+use crate::ich::StableHashingContext;
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
                                            StableHasherResult};
@@ -46,7 +46,7 @@ impl IntegerExt for Integer {
         }
     }
 
-    /// Get the Integer type from an attr::IntType.
+    /// Gets the Integer type from an attr::IntType.
     fn from_attr<C: HasDataLayout>(cx: &C, ity: attr::IntType) -> Integer {
         let dl = cx.data_layout();
 
@@ -62,7 +62,7 @@ impl IntegerExt for Integer {
         }
     }
 
-    /// Find the appropriate Integer type and signedness for the given
+    /// Finds the appropriate Integer type and signedness for the given
     /// signed discriminant range and #[repr] attribute.
     /// N.B.: u128 values above i128::MAX will be treated as signed, but
     /// that shouldn't affect anything, other than maybe debuginfo.
@@ -1686,7 +1686,7 @@ impl<'a, 'tcx, C> TyLayoutMethods<'tcx, C> for Ty<'tcx>
                             tcx.types.re_static,
                             tcx.mk_array(tcx.types.usize, 3),
                         )
-                        /* FIXME use actual fn pointers
+                        /* FIXME: use actual fn pointers
                         Warning: naively computing the number of entries in the
                         vtable by counting the methods on the trait + methods on
                         all parent traits does not work, because some methods can
@@ -1872,7 +1872,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for Variants {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use ty::layout::Variants::*;
+        use crate::ty::layout::Variants::*;
         mem::discriminant(self).hash_stable(hcx, hasher);
 
         match *self {
@@ -1908,7 +1908,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for FieldPlacement {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use ty::layout::FieldPlacement::*;
+        use crate::ty::layout::FieldPlacement::*;
         mem::discriminant(self).hash_stable(hcx, hasher);
 
         match *self {
@@ -1941,7 +1941,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for Abi {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use ty::layout::Abi::*;
+        use crate::ty::layout::Abi::*;
         mem::discriminant(self).hash_stable(hcx, hasher);
 
         match *self {
@@ -1975,7 +1975,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for Scalar {
     }
 }
 
-impl_stable_hash_for!(struct ::ty::layout::LayoutDetails {
+impl_stable_hash_for!(struct crate::ty::layout::LayoutDetails {
     variants,
     fields,
     abi,
@@ -1983,7 +1983,7 @@ impl_stable_hash_for!(struct ::ty::layout::LayoutDetails {
     align
 });
 
-impl_stable_hash_for!(enum ::ty::layout::Integer {
+impl_stable_hash_for!(enum crate::ty::layout::Integer {
     I8,
     I16,
     I32,
@@ -1991,13 +1991,13 @@ impl_stable_hash_for!(enum ::ty::layout::Integer {
     I128
 });
 
-impl_stable_hash_for!(enum ::ty::layout::Primitive {
+impl_stable_hash_for!(enum crate::ty::layout::Primitive {
     Int(integer, signed),
     Float(fty),
     Pointer
 });
 
-impl_stable_hash_for!(struct ::ty::layout::AbiAndPrefAlign {
+impl_stable_hash_for!(struct crate::ty::layout::AbiAndPrefAlign {
     abi,
     pref
 });
@@ -2023,7 +2023,7 @@ impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for LayoutError<'gcx>
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
-        use ty::layout::LayoutError::*;
+        use crate::ty::layout::LayoutError::*;
         mem::discriminant(self).hash_stable(hcx, hasher);
 
         match *self {
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 26b4735d926a5..02e4fb12af5c9 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -4,31 +4,31 @@ pub use self::BorrowKind::*;
 pub use self::IntVarValue::*;
 pub use self::fold::TypeFoldable;
 
-use hir::{map as hir_map, FreevarMap, TraitMap};
-use hir::Node;
-use hir::def::{Def, CtorKind, ExportMap};
-use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
-use hir::map::DefPathData;
+use crate::hir::{map as hir_map, FreevarMap, GlobMap, TraitMap};
+use crate::hir::Node;
+use crate::hir::def::{Def, CtorKind, ExportMap};
+use crate::hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
+use crate::hir::map::DefPathData;
 use rustc_data_structures::svh::Svh;
-use ich::Fingerprint;
-use ich::StableHashingContext;
-use infer::canonical::Canonical;
-use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
-use middle::resolve_lifetime::ObjectLifetimeDefault;
-use mir::Mir;
-use mir::interpret::{GlobalId, ErrorHandled};
-use mir::GeneratorLayout;
-use session::CrateDisambiguator;
-use traits::{self, Reveal};
-use ty;
-use ty::layout::VariantIdx;
-use ty::subst::{Subst, Substs};
-use ty::util::{IntTypeExt, Discr};
-use ty::walk::TypeWalker;
-use util::captures::Captures;
-use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
+use crate::ich::Fingerprint;
+use crate::ich::StableHashingContext;
+use crate::infer::canonical::Canonical;
+use crate::middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
+use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
+use crate::mir::Mir;
+use crate::mir::interpret::{GlobalId, ErrorHandled};
+use crate::mir::GeneratorLayout;
+use crate::session::CrateDisambiguator;
+use crate::traits::{self, Reveal};
+use crate::ty;
+use crate::ty::layout::VariantIdx;
+use crate::ty::subst::{Subst, Substs};
+use crate::ty::util::{IntTypeExt, Discr};
+use crate::ty::walk::TypeWalker;
+use crate::util::captures::Captures;
+use crate::util::nodemap::{NodeSet, DefIdMap, FxHashMap};
 use arena::SyncDroplessArena;
-use session::DataTypeKind;
+use crate::session::DataTypeKind;
 
 use serialize::{self, Encodable, Encoder};
 use std::cell::RefCell;
@@ -39,18 +39,18 @@ use std::ops::Deref;
 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
 use std::slice;
 use std::{mem, ptr};
-use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
+use syntax::ast::{self, Name, Ident, NodeId};
 use syntax::attr;
 use syntax::ext::hygiene::Mark;
 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
-use syntax_pos::{DUMMY_SP, Span};
+use syntax_pos::Span;
 
 use smallvec;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
                                            HashStable};
 
-use hir;
+use crate::hir;
 
 pub use self::sty::{Binder, BoundTy, BoundTyKind, BoundVar, DebruijnIndex, INNERMOST};
 pub use self::sty::{FnSig, GenSig, CanonicalPolyFnSig, PolyFnSig, PolyGenSig};
@@ -73,8 +73,8 @@ pub use self::binding::BindingMode::*;
 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
 pub use self::context::{Lift, TypeckTables, CtxtInterners};
 pub use self::context::{
-    UserTypeAnnotationIndex, UserTypeAnnotation, CanonicalUserTypeAnnotation,
-    CanonicalUserTypeAnnotations,
+    UserTypeAnnotationIndex, UserType, CanonicalUserType,
+    CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, ResolvedOpaqueTy,
 };
 
 pub use self::instance::{Instance, InstanceDef};
@@ -115,16 +115,6 @@ mod sty;
 
 // Data types
 
-/// The complete set of all analyses described in this module. This is
-/// produced by the driver and fed to codegen and later passes.
-///
-/// N.B., these contents are being migrated into queries using the
-/// *on-demand* infrastructure.
-#[derive(Clone)]
-pub struct CrateAnalysis {
-    pub glob_map: hir::GlobMap,
-}
-
 #[derive(Clone)]
 pub struct Resolutions {
     pub freevars: FreevarMap,
@@ -132,6 +122,7 @@ pub struct Resolutions {
     pub maybe_unused_trait_imports: NodeSet,
     pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
     pub export_map: ExportMap,
+    pub glob_map: GlobMap,
     /// Extern prelude entries. The value is `true` if the entry was introduced
     /// via `extern crate` item and not `--extern` option or compiler built-in.
     pub extern_prelude: FxHashMap<Name, bool>,
@@ -144,8 +135,8 @@ pub enum AssociatedItemContainer {
 }
 
 impl AssociatedItemContainer {
-    /// Asserts that this is the def-id of an associated item declared
-    /// in a trait, and returns the trait def-id.
+    /// Asserts that this is the `DefId` of an associated item declared
+    /// in a trait, and returns the trait `DefId`.
     pub fn assert_trait(&self) -> DefId {
         match *self {
             TraitContainer(id) => id,
@@ -163,7 +154,7 @@ impl AssociatedItemContainer {
 
 /// The "header" of an impl is everything outside the body: a Self type, a trait
 /// ref (in the case of a trait impl), and a set of predicates (from the
-/// bounds/where clauses).
+/// bounds / where-clauses).
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct ImplHeader<'tcx> {
     pub impl_def_id: DefId,
@@ -337,7 +328,7 @@ pub enum Variance {
 /// item.
 pub struct CrateVariancesMap {
     /// For each item with generics, maps to a vector of the variance
-    /// of its generics.  If an item has no generics, it will have no
+    /// of its generics. If an item has no generics, it will have no
     /// entry.
     pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
 
@@ -347,7 +338,7 @@ pub struct CrateVariancesMap {
 
 impl Variance {
     /// `a.xform(b)` combines the variance of a context with the
-    /// variance of a type with the following meaning.  If we are in a
+    /// variance of a type with the following meaning. If we are in a
     /// context with variance `a`, and we encounter a type argument in
     /// a position with variance `b`, then `a.xform(b)` is the new
     /// variance with which the argument appears.
@@ -371,10 +362,10 @@ impl Variance {
     /// The ambient variance is covariant. A `fn` type is
     /// contravariant with respect to its parameters, so the variance
     /// within which both pointer types appear is
-    /// `Covariant.xform(Contravariant)`, or `Contravariant`.  `*const
+    /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
     /// T` is covariant with respect to `T`, so the variance within
     /// which the first `Vec<i32>` appears is
-    /// `Contravariant.xform(Covariant)` or `Contravariant`.  The same
+    /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
     /// is true for its `i32` argument. In the `*mut T` case, the
     /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
     /// and hence the outermost type is `Invariant` with respect to
@@ -498,12 +489,12 @@ pub struct TyS<'tcx> {
     /// So, for a type without any late-bound things, like `u32`, this
     /// will be *innermost*, because that is the innermost binder that
     /// captures nothing. But for a type `&'D u32`, where `'D` is a
-    /// late-bound region with debruijn index `D`, this would be `D + 1`
+    /// late-bound region with De Bruijn index `D`, this would be `D + 1`
     /// -- the binder itself does not capture `D`, but `D` is captured
     /// by an inner binder.
     ///
     /// We call this concept an "exclusive" binder `D` because all
-    /// debruijn indices within the type are contained within `0..D`
+    /// De Bruijn indices within the type are contained within `0..D`
     /// (exclusive).
     outer_exclusive_binder: ty::DebruijnIndex,
 }
@@ -729,9 +720,9 @@ pub struct UpvarPath {
     pub hir_id: hir::HirId,
 }
 
-/// Upvars do not get their own node-id. Instead, we use the pair of
-/// the original var id (that is, the root variable that is referenced
-/// by the upvar) and the id of the closure expression.
+/// Upvars do not get their own `NodeId`. Instead, we use the pair of
+/// the original var ID (that is, the root variable that is referenced
+/// by the upvar) and the ID of the closure expression.
 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub struct UpvarId {
     pub var_path: UpvarPath,
@@ -743,7 +734,7 @@ pub enum BorrowKind {
     /// Data must be immutable and is aliasable.
     ImmBorrow,
 
-    /// Data must be immutable but not aliasable.  This kind of borrow
+    /// Data must be immutable but not aliasable. This kind of borrow
     /// cannot currently be expressed by the user and is used only in
     /// implicit closure bindings. It is needed when the closure
     /// is borrowing or mutating a mutable referent, e.g.:
@@ -1105,7 +1096,7 @@ impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
     /// Performs a substitution suitable for going from a
     /// poly-trait-ref to supertraits that must hold if that
     /// poly-trait-ref holds. This is slightly different from a normal
-    /// substitution in terms of what happens with bound regions.  See
+    /// substitution in terms of what happens with bound regions. See
     /// lengthy comment below for details.
     pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
                             trait_ref: &ty::PolyTraitRef<'tcx>)
@@ -1244,7 +1235,7 @@ pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
 /// This kind of predicate has no *direct* correspondent in the
 /// syntax, but it roughly corresponds to the syntactic forms:
 ///
-/// 1. `T: TraitRef<..., Item=Type>`
+/// 1. `T: TraitRef<..., Item = Type>`
 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
 ///
 /// In particular, form #1 is "desugared" to the combination of a
@@ -1465,8 +1456,8 @@ impl<'tcx> Predicate<'tcx> {
 }
 
 /// Represents the bounds declared on a particular set of type
-/// parameters.  Should eventually be generalized into a flag list of
-/// where clauses.  You can obtain a `InstantiatedPredicates` list from a
+/// parameters. Should eventually be generalized into a flag list of
+/// where-clauses. You can obtain a `InstantiatedPredicates` list from a
 /// `GenericPredicates` by using the `instantiate` method. Note that this method
 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
 /// the `GenericPredicates` are expressed in terms of the bound type
@@ -1480,7 +1471,7 @@ impl<'tcx> Predicate<'tcx> {
 ///     struct Foo<T,U:Bar<T>> { ... }
 ///
 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
-/// `[[], [U:Bar<T>]]`.  Now if there were some particular reference
+/// `[[], [U:Bar<T>]]`. Now if there were some particular reference
 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
 /// [usize:Bar<isize>]]`.
 #[derive(Clone)]
@@ -1546,7 +1537,7 @@ impl UniverseIndex {
 
     /// Returns the "next" universe index in order -- this new index
     /// is considered to extend all previous universes. This
-    /// corresponds to entering a `forall` quantifier.  So, for
+    /// corresponds to entering a `forall` quantifier. So, for
     /// example, suppose we have this type in universe `U`:
     ///
     /// ```
@@ -1628,7 +1619,7 @@ pub struct ParamEnv<'tcx> {
 
 impl<'tcx> ParamEnv<'tcx> {
     /// Construct a trait environment suitable for contexts where
-    /// there are no where clauses in scope. Hidden types (like `impl
+    /// there are no where-clauses in scope. Hidden types (like `impl
     /// Trait`) are left hidden, so this is suitable for ordinary
     /// type-checking.
     #[inline]
@@ -1636,12 +1627,12 @@ impl<'tcx> ParamEnv<'tcx> {
         Self::new(List::empty(), Reveal::UserFacing, None)
     }
 
-    /// Construct a trait environment with no where clauses in scope
+    /// Construct a trait environment with no where-clauses in scope
     /// where the values of all `impl Trait` and other hidden types
     /// are revealed. This is suitable for monomorphized, post-typeck
     /// environments like codegen or doing optimizations.
     ///
-    /// N.B. If you want to have predicates in scope, use `ParamEnv::new`,
+    /// N.B., if you want to have predicates in scope, use `ParamEnv::new`,
     /// or invoke `param_env.with_reveal_all()`.
     #[inline]
     pub fn reveal_all() -> Self {
@@ -1660,7 +1651,7 @@ impl<'tcx> ParamEnv<'tcx> {
 
     /// Returns a new parameter environment with the same clauses, but
     /// which "reveals" the true results of projections in all cases
-    /// (even for associated types that are specializable).  This is
+    /// (even for associated types that are specializable). This is
     /// the desired behavior during codegen and certain other special
     /// contexts; normally though we want to use `Reveal::UserFacing`,
     /// which is the default.
@@ -1745,7 +1736,7 @@ impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
 
 #[derive(Copy, Clone, Debug)]
 pub struct Destructor {
-    /// The def-id of the destructor method
+    /// The `DefId` of the destructor method
     pub did: DefId,
 }
 
@@ -1790,20 +1781,21 @@ pub struct VariantDef {
 }
 
 impl<'a, 'gcx, 'tcx> VariantDef {
-    /// Create a new `VariantDef`.
+    /// Creates a new `VariantDef`.
     ///
-    /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
-    /// and for everything else, it is the variant DefId.
+    /// - `did` is the `DefId` used for the variant.
+    /// This is the constructor `DefId` for tuple stucts, and the variant `DefId` for everything
+    /// else.
     /// - `attribute_def_id` is the DefId that has the variant's attributes.
-    /// this is the struct DefId for structs, and the variant DefId for variants.
+    /// This is the struct `DefId` for structs, and the variant `DefId` for variants.
     ///
-    /// Note that we *could* use the constructor DefId, because the constructor attributes
+    /// Note that we *could* use the constructor `DefId`, because the constructor attributes
     /// redirect to the base attributes, but compiling a small crate requires
-    /// loading the AdtDefs for all the structs in the universe (e.g., coherence for any
+    /// loading the `AdtDef`s for all the structs in the universe (e.g., coherence for any
     /// built-in trait), and we do not want to load attributes twice.
     ///
     /// If someone speeds up attribute loading to not be a performance concern, they can
-    /// remove this hack and use the constructor DefId everywhere.
+    /// remove this hack and use the constructor `DefId` everywhere.
     pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                did: DefId,
                ident: Ident,
@@ -2058,13 +2050,13 @@ impl ReprOptions {
     }
 
     /// Returns `true` if this `#[repr()]` should inhibit struct field reordering
-    /// optimizations, such as with repr(C), repr(packed(1)), or repr(<int>).
+    /// optimizations, such as with `repr(C)`, `repr(packed(1))`, or `repr(<int>)`.
     pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
         self.flags.intersects(ReprFlags::IS_UNOPTIMISABLE) || self.pack == 1 ||
             self.int.is_some()
     }
 
-    /// Returns true if this `#[repr()]` should inhibit union abi optimisations
+    /// Returns `true` if this `#[repr()]` should inhibit union ABI optimisations.
     pub fn inhibit_union_abi_opt(&self) -> bool {
         self.c()
     }
@@ -2179,14 +2171,14 @@ impl<'a, 'gcx, 'tcx> AdtDef {
         self.flags.contains(AdtFlags::HAS_CTOR)
     }
 
-    /// Returns whether this type is `#[fundamental]` for the purposes
+    /// Returns `true` if this type is `#[fundamental]` for the purposes
     /// of coherence checking.
     #[inline]
     pub fn is_fundamental(&self) -> bool {
         self.flags.contains(AdtFlags::IS_FUNDAMENTAL)
     }
 
-    /// Returns `true` if this is PhantomData<T>.
+    /// Returns `true` if this is `PhantomData<T>`.
     #[inline]
     pub fn is_phantom_data(&self) -> bool {
         self.flags.contains(AdtFlags::IS_PHANTOM_DATA)
@@ -2208,7 +2200,7 @@ impl<'a, 'gcx, 'tcx> AdtDef {
         self.flags.contains(AdtFlags::IS_BOX)
     }
 
-    /// Returns whether this type has a destructor.
+    /// Returns `true` if this type has a destructor.
     pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
         self.destructor(tcx).is_some()
     }
@@ -2286,7 +2278,7 @@ impl<'a, 'gcx, 'tcx> AdtDef {
                     })
                 } else {
                     info!("invalid enum discriminant: {:#?}", val);
-                    ::mir::interpret::struct_error(
+                    crate::mir::interpret::struct_error(
                         tcx.at(tcx.def_span(expr_did)),
                         "constant evaluation of enum discriminant resulted in non-integer",
                     ).emit();
@@ -2329,7 +2321,7 @@ impl<'a, 'gcx, 'tcx> AdtDef {
         })
     }
 
-    /// Compute the discriminant value used by a specific variant.
+    /// Computes the discriminant value used by a specific variant.
     /// Unlike `discriminants`, this is (amortized) constant-time,
     /// only doing at most one query for evaluating an explicit
     /// discriminant (the last one before the requested variant),
@@ -2345,9 +2337,9 @@ impl<'a, 'gcx, 'tcx> AdtDef {
         explicit_value.checked_add(tcx, offset as u128).0
     }
 
-    /// Yields a DefId for the discriminant and an offset to add to it
+    /// Yields a `DefId` for the discriminant and an offset to add to it
     /// Alternatively, if there is no explicit discriminant, returns the
-    /// inferred discriminant directly
+    /// inferred discriminant directly.
     pub fn discriminant_def_for_variant(
         &self,
         variant_index: VariantIdx,
@@ -2377,30 +2369,17 @@ impl<'a, 'gcx, 'tcx> AdtDef {
     }
 
     /// Returns a list of types such that `Self: Sized` if and only
-    /// if that type is Sized, or `TyErr` if this type is recursive.
+    /// if that type is `Sized`, or `TyErr` if this type is recursive.
     ///
-    /// Oddly enough, checking that the sized-constraint is Sized is
+    /// Oddly enough, checking that the sized-constraint is `Sized` is
     /// actually more expressive than checking all members:
-    /// the Sized trait is inductive, so an associated type that references
-    /// Self would prevent its containing ADT from being Sized.
+    /// the `Sized` trait is inductive, so an associated type that references
+    /// `Self` would prevent its containing ADT from being `Sized`.
     ///
     /// Due to normalization being eager, this applies even if
-    /// the associated type is behind a pointer, e.g., issue #31299.
+    /// the associated type is behind a pointer (e.g., issue #31299).
     pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
-        match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
-            Ok(tys) => tys,
-            Err(mut bug) => {
-                debug!("adt_sized_constraint: {:?} is recursive", self);
-                // This should be reported as an error by `check_representable`.
-                //
-                // Consider the type as Sized in the meanwhile to avoid
-                // further errors. Delay our `bug` diagnostic here to get
-                // emitted later as well in case we accidentally otherwise don't
-                // emit an error.
-                bug.delay_as_bug();
-                tcx.intern_type_list(&[tcx.types.err])
-            }
-        }
+        tcx.adt_sized_constraint(self.did).0
     }
 
     fn sized_constraint_for_ty(&self,
@@ -2489,7 +2468,7 @@ impl<'a, 'gcx, 'tcx> FieldDef {
     }
 }
 
-/// Represents the various closure traits in the Rust language. This
+/// Represents the various closure traits in the language. This
 /// will determine the type of the environment (`self`, in the
 /// desugaring) argument that the closure expects.
 ///
@@ -2561,7 +2540,7 @@ impl<'tcx> TyS<'tcx> {
         TypeWalker::new(self)
     }
 
-    /// Iterator that walks the immediate children of `self`.  Hence
+    /// Iterator that walks the immediate children of `self`. Hence
     /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
     /// (but not `i32`, like `walk`).
     pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
@@ -2569,7 +2548,7 @@ impl<'tcx> TyS<'tcx> {
     }
 
     /// Walks `ty` and any types appearing within `ty`, invoking the
-    /// callback `f` on each type. If the callback returns false, then the
+    /// callback `f` on each type. If the callback returns `false`, then the
     /// children of the current type are ignored.
     ///
     /// Note: prefer `ty.walk()` where possible.
@@ -2679,7 +2658,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.typeck_tables_of(self.hir().body_owner_def_id(body))
     }
 
-    /// Returns an iterator of the def-ids for all body-owners in this
+    /// Returns an iterator of the `DefId`s for all body-owners in this
     /// crate. If you would prefer to iterate over the bodies
     /// themselves, you can do `self.hir().krate().body_ids.iter()`.
     pub fn body_owners(
@@ -2803,7 +2782,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
         variant.fields.iter().position(|field| {
-            self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
+            self.adjust_ident(ident, variant.did, hir::DUMMY_HIR_ID).0 == field.ident.modern()
         })
     }
 
@@ -2926,7 +2905,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
+    /// Returns the possibly-auto-generated MIR of a `(DefId, Subst)` pair.
     pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
                         -> &'gcx Mir<'gcx>
     {
@@ -2946,26 +2925,16 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Given the DefId of an item, returns its MIR, borrowed immutably.
-    /// Returns None if there is no MIR for the DefId
-    pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
-        if self.is_mir_available(did) {
-            Some(self.optimized_mir(did))
-        } else {
-            None
-        }
-    }
-
-    /// Get the attributes of a definition.
+    /// Gets the attributes of a definition.
     pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
-        if let Some(id) = self.hir().as_local_node_id(did) {
-            Attributes::Borrowed(self.hir().attrs(id))
+        if let Some(id) = self.hir().as_local_hir_id(did) {
+            Attributes::Borrowed(self.hir().attrs_by_hir_id(id))
         } else {
             Attributes::Owned(self.item_attrs(did))
         }
     }
 
-    /// Determine whether an item is annotated with an attribute.
+    /// Determines whether an item is annotated with an attribute.
     pub fn has_attr(self, did: DefId, attr: &str) -> bool {
         attr::contains_name(&self.get_attrs(did), attr)
     }
@@ -2979,14 +2948,14 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
     }
 
-    /// Given the def-id of an impl, return the def_id of the trait it implements.
-    /// If it implements no trait, return `None`.
+    /// Given the `DefId` of an impl, returns the `DefId` of the trait it implements.
+    /// If it implements no trait, returns `None`.
     pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
         self.impl_trait_ref(def_id).map(|tr| tr.def_id)
     }
 
-    /// If the given defid describes a method belonging to an impl, return the
-    /// def-id of the impl that the method belongs to. Otherwise, return `None`.
+    /// If the given defid describes a method belonging to an impl, returns the
+    /// `DefId` of the impl that the method belongs to; otherwise, returns `None`.
     pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
         let item = if def_id.krate != LOCAL_CRATE {
             if let Some(Def::Method(_)) = self.describe_def(def_id) {
@@ -3010,21 +2979,21 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     /// with the name of the crate containing the impl.
     pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
         if impl_did.is_local() {
-            let node_id = self.hir().as_local_node_id(impl_did).unwrap();
-            Ok(self.hir().span(node_id))
+            let hir_id = self.hir().as_local_hir_id(impl_did).unwrap();
+            Ok(self.hir().span_by_hir_id(hir_id))
         } else {
             Err(self.crate_name(impl_did.krate))
         }
     }
 
-    // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
-    // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
-    // definition's parent/scope to perform comparison.
+    /// Hygienically compares a use-site name (`use_name`) for a field or an associated item with
+    /// its supposed definition name (`def_name`). The method also needs `DefId` of the supposed
+    /// definition's parent/scope to perform comparison.
     pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
-        self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
+        self.adjust_ident(use_name, def_parent_def_id, hir::DUMMY_HIR_ID).0 == def_name.modern()
     }
 
-    pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
+    pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: hir::HirId) -> (Ident, DefId) {
         ident = ident.modern();
         let target_expansion = match scope.krate {
             LOCAL_CRATE => self.hir().definitions().expansion_that_defined(scope.index),
@@ -3033,8 +3002,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         let scope = match ident.span.adjust(target_expansion) {
             Some(actual_expansion) =>
                 self.hir().definitions().parent_module_of_macro_def(actual_expansion),
-            None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
-            None => self.hir().get_module_parent(block),
+            None if block == hir::DUMMY_HIR_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
+            None => self.hir().get_module_parent_by_hir_id(block),
         };
         (ident, scope)
     }
@@ -3101,7 +3070,10 @@ fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Asso
               parent_item.node)
 }
 
-/// Calculates the Sized-constraint.
+#[derive(Clone)]
+pub struct AdtSizedConstraint<'tcx>(pub &'tcx [Ty<'tcx>]);
+
+/// Calculates the `Sized` constraint.
 ///
 /// In fact, there are only a few options for the types in the constraint:
 ///     - an obviously-unsized type
@@ -3112,7 +3084,7 @@ fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Asso
 ///       check should catch this case.
 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                   def_id: DefId)
-                                  -> &'tcx [Ty<'tcx>] {
+                                  -> AdtSizedConstraint<'tcx> {
     let def = tcx.adt_def(def_id);
 
     let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
@@ -3123,14 +3095,14 @@ fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
     debug!("adt_sized_constraint: {:?} => {:?}", def, result);
 
-    result
+    AdtSizedConstraint(result)
 }
 
 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                      def_id: DefId)
                                      -> Lrc<Vec<DefId>> {
-    let id = tcx.hir().as_local_node_id(def_id).unwrap();
-    let item = tcx.hir().expect_item(id);
+    let id = tcx.hir().as_local_hir_id(def_id).unwrap();
+    let item = tcx.hir().expect_item_by_hir_id(id);
     let vec: Vec<_> = match item.node {
         hir::ItemKind::Trait(.., ref trait_item_refs) => {
             trait_item_refs.iter()
@@ -3154,9 +3126,9 @@ fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
     tcx.hir().span_if_local(def_id).unwrap()
 }
 
-/// If the given def ID describes an item belonging to a trait,
-/// return the ID of the trait that the trait item belongs to.
-/// Otherwise, return `None`.
+/// If the given `DefId` describes an item belonging to a trait,
+/// returns the `DefId` of the trait that the trait item belongs to;
+/// otherwise, returns `None`.
 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
     tcx.opt_associated_item(def_id)
         .and_then(|associated_item| {
@@ -3179,18 +3151,6 @@ pub fn is_impl_trait_defn(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<DefI
     None
 }
 
-/// Returns `true` if `def_id` is a trait alias.
-pub fn is_trait_alias(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> bool {
-    if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
-        if let Node::Item(item) = tcx.hir().get(node_id) {
-            if let hir::ItemKind::TraitAlias(..) = item.node {
-                return true;
-            }
-        }
-    }
-    false
-}
-
 /// See `ParamEnv` struct definition for details.
 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                        def_id: DefId)
@@ -3223,8 +3183,8 @@ fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         if tcx.sess.opts.debugging_opts.chalk { Some(def_id) } else { None }
     );
 
-    let body_id = tcx.hir().as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
-        tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.node_id)
+    let body_id = tcx.hir().as_local_hir_id(def_id).map_or(hir::DUMMY_HIR_ID, |id| {
+        tcx.hir().maybe_body_owned_by_by_hir_id(id).map_or(id, |body| body.hir_id)
     });
     let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
     traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
@@ -3263,10 +3223,9 @@ fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
 }
 
-/// If `def_id` is an issue 33140 hack impl, return its self type. Otherwise
-/// return None.
+/// If `def_id` is an issue 33140 hack impl, returns its self type; otherwise, returns `None`.
 ///
-/// See ImplOverlapKind::Issue33140 for more details.
+/// See [`ImplOverlapKind::Issue33140`] for more details.
 fn issue33140_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                 def_id: DefId)
                                 -> Option<Ty<'tcx>>
diff --git a/src/librustc/ty/outlives.rs b/src/librustc/ty/outlives.rs
index ca2d5cd718c64..5b21ed5abd77b 100644
--- a/src/librustc/ty/outlives.rs
+++ b/src/librustc/ty/outlives.rs
@@ -3,7 +3,7 @@
 // RFC for reference.
 
 use smallvec::SmallVec;
-use ty::{self, Ty, TyCtxt, TypeFoldable};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
 
 #[derive(Debug)]
 pub enum Component<'tcx> {
diff --git a/src/librustc/ty/query/README.md b/src/librustc/ty/query/README.md
index 0fcaef5de54c2..4b5e08cecd99c 100644
--- a/src/librustc/ty/query/README.md
+++ b/src/librustc/ty/query/README.md
@@ -1,302 +1,3 @@
-# The Rust Compiler Query System
-
-The Compiler Query System is the key to our new demand-driven
-organization.  The idea is pretty simple. You have various queries
-that compute things about the input -- for example, there is a query
-called `type_of(def_id)` that, given the def-id of some item, will
-compute the type of that item and return it to you.
-
-Query execution is **memoized** -- so the first time you invoke a
-query, it will go do the computation, but the next time, the result is
-returned from a hashtable. Moreover, query execution fits nicely into
-**incremental computation**; the idea is roughly that, when you do a
-query, the result **may** be returned to you by loading stored data
-from disk (but that's a separate topic we won't discuss further here).
-
-The overall vision is that, eventually, the entire compiler
-control-flow will be query driven. There will effectively be one
-top-level query ("compile") that will run compilation on a crate; this
-will in turn demand information about that crate, starting from the
-*end*.  For example:
-
-- This "compile" query might demand to get a list of codegen-units
-  (i.e., modules that need to be compiled by LLVM).
-- But computing the list of codegen-units would invoke some subquery
-  that returns the list of all modules defined in the Rust source.
-- That query in turn would invoke something asking for the HIR.
-- This keeps going further and further back until we wind up doing the
-  actual parsing.
-
-However, that vision is not fully realized. Still, big chunks of the
-compiler (for example, generating MIR) work exactly like this.
-
-### Invoking queries
-
-To invoke a query is simple. The tcx ("type context") offers a method
-for each defined query. So, for example, to invoke the `type_of`
-query, you would just do this:
-
-```rust
-let ty = tcx.type_of(some_def_id);
-```
-
-### Cycles between queries
-
-Currently, cycles during query execution should always result in a
-compilation error. Typically, they arise because of illegal programs
-that contain cyclic references they shouldn't (though sometimes they
-arise because of compiler bugs, in which case we need to factor our
-queries in a more fine-grained fashion to avoid them).
-
-However, it is nonetheless often useful to *recover* from a cycle
-(after reporting an error, say) and try to soldier on, so as to give a
-better user experience. In order to recover from a cycle, you don't
-get to use the nice method-call-style syntax. Instead, you invoke
-using the `try_get` method, which looks roughly like this:
-
-```rust
-use ty::query::queries;
-...
-match queries::type_of::try_get(tcx, DUMMY_SP, self.did) {
-  Ok(result) => {
-    // no cycle occurred! You can use `result`
-  }
-  Err(err) => {
-    // A cycle occurred! The error value `err` is a `DiagnosticBuilder`,
-    // meaning essentially an "in-progress", not-yet-reported error message.
-    // See below for more details on what to do here.
-  }
-}
-```
-
-So, if you get back an `Err` from `try_get`, then a cycle *did* occur. This means that
-you must ensure that a compiler error message is reported. You can do that in two ways:
-
-The simplest is to invoke `err.emit()`. This will emit the cycle error to the user.
-
-However, often cycles happen because of an illegal program, and you
-know at that point that an error either already has been reported or
-will be reported due to this cycle by some other bit of code. In that
-case, you can invoke `err.cancel()` to not emit any error. It is
-traditional to then invoke:
-
-```
-tcx.sess.delay_span_bug(some_span, "some message")
-```
-
-`delay_span_bug()` is a helper that says: we expect a compilation
-error to have happened or to happen in the future; so, if compilation
-ultimately succeeds, make an ICE with the message `"some
-message"`. This is basically just a precaution in case you are wrong.
-
-### How the compiler executes a query
-
-So you may be wondering what happens when you invoke a query
-method. The answer is that, for each query, the compiler maintains a
-cache -- if your query has already been executed, then, the answer is
-simple: we clone the return value out of the cache and return it
-(therefore, you should try to ensure that the return types of queries
-are cheaply cloneable; insert a `Rc` if necessary).
-
-#### Providers
-
-If, however, the query is *not* in the cache, then the compiler will
-try to find a suitable **provider**. A provider is a function that has
-been defined and linked into the compiler somewhere that contains the
-code to compute the result of the query.
-
-**Providers are defined per-crate.** The compiler maintains,
-internally, a table of providers for every crate, at least
-conceptually. Right now, there are really two sets: the providers for
-queries about the **local crate** (that is, the one being compiled)
-and providers for queries about **external crates** (that is,
-dependencies of the local crate). Note that what determines the crate
-that a query is targeting is not the *kind* of query, but the *key*.
-For example, when you invoke `tcx.type_of(def_id)`, that could be a
-local query or an external query, depending on what crate the `def_id`
-is referring to (see the `self::keys::Key` trait for more information
-on how that works).
-
-Providers always have the same signature:
-
-```rust
-fn provider<'cx, 'tcx>(tcx: TyCtxt<'cx, 'tcx, 'tcx>,
-                       key: QUERY_KEY)
-                       -> QUERY_RESULT
-{
-    ...
-}
-```
-
-Providers take two arguments: the `tcx` and the query key. Note also
-that they take the *global* tcx (i.e., they use the `'tcx` lifetime
-twice), rather than taking a tcx with some active inference context.
-They return the result of the query.
-
-####  How providers are setup
-
-When the tcx is created, it is given the providers by its creator using
-the `Providers` struct. This struct is generate by the macros here, but it
-is basically a big list of function pointers:
-
-```rust
-struct Providers {
-    type_of: for<'cx, 'tcx> fn(TyCtxt<'cx, 'tcx, 'tcx>, DefId) -> Ty<'tcx>,
-    ...
-}
-```
-
-At present, we have one copy of the struct for local crates, and one
-for external crates, though the plan is that we may eventually have
-one per crate.
-
-These `Provider` structs are ultimately created and populated by
-`librustc_driver`, but it does this by distributing the work
-throughout the other `rustc_*` crates. This is done by invoking
-various `provide` functions. These functions tend to look something
-like this:
-
-```rust
-pub fn provide(providers: &mut Providers) {
-    *providers = Providers {
-        type_of,
-        ..*providers
-    };
-}
-```
-
-That is, they take an `&mut Providers` and mutate it in place. Usually
-we use the formulation above just because it looks nice, but you could
-as well do `providers.type_of = type_of`, which would be equivalent.
-(Here, `type_of` would be a top-level function, defined as we saw
-before.) So, if we want to add a provider for some other query,
-let's call it `fubar`, into the crate above, we might modify the `provide()`
-function like so:
-
-```rust
-pub fn provide(providers: &mut Providers) {
-    *providers = Providers {
-        type_of,
-        fubar,
-        ..*providers
-    };
-}
-
-fn fubar<'cx, 'tcx>(tcx: TyCtxt<'cx, 'tcx>, key: DefId) -> Fubar<'tcx> { .. }
-```
-
-NB. Most of the `rustc_*` crates only provide **local
-providers**. Almost all **extern providers** wind up going through the
-`rustc_metadata` crate, which loads the information from the crate
-metadata.  But in some cases there are crates that provide queries for
-*both* local and external crates, in which case they define both a
-`provide` and a `provide_extern` function that `rustc_driver` can
-invoke.
-
-### Adding a new kind of query
-
-So suppose you want to add a new kind of query, how do you do so?
-Well, defining a query takes place in two steps:
-
-1. first, you have to specify the query name and arguments; and then,
-2. you have to supply query providers where needed.
-
-To specify the query name and arguments, you simply add an entry
-to the big macro invocation in `mod.rs`. This will probably have changed
-by the time you read this README, but at present it looks something
-like:
-
-```
-define_queries! { <'tcx>
-    /// Records the type of every item.
-    [] fn type_of: TypeOfItem(DefId) -> Ty<'tcx>,
-
-    ...
-}
-```
-
-Each line of the macro defines one query. The name is broken up like this:
-
-```
-[] fn type_of: TypeOfItem(DefId) -> Ty<'tcx>,
-^^    ^^^^^^^  ^^^^^^^^^^ ^^^^^     ^^^^^^^^
-|     |        |          |         |
-|     |        |          |         result type of query
-|     |        |          query key type
-|     |        dep-node constructor
-|     name of query
-query flags
-```
-
-Let's go over them one by one:
-
-- **Query flags:** these are largely unused right now, but the intention
-  is that we'll be able to customize various aspects of how the query is
-  processed.
-- **Name of query:** the name of the query method
-  (`tcx.type_of(..)`). Also used as the name of a struct
-  (`ty::query::queries::type_of`) that will be generated to represent
-  this query.
-- **Dep-node constructor:** indicates the constructor function that
-  connects this query to incremental compilation. Typically, this is a
-  `DepNode` variant, which can be added by modifying the
-  `define_dep_nodes!` macro invocation in
-  `librustc/dep_graph/dep_node.rs`.
-  - However, sometimes we use a custom function, in which case the
-    name will be in snake case and the function will be defined at the
-    bottom of the file. This is typically used when the query key is
-    not a def-id, or just not the type that the dep-node expects.
-- **Query key type:** the type of the argument to this query.
-  This type must implement the `ty::query::keys::Key` trait, which
-  defines (for example) how to map it to a crate, and so forth.
-- **Result type of query:** the type produced by this query. This type
-  should (a) not use `RefCell` or other interior mutability and (b) be
-  cheaply cloneable. Interning or using `Rc` or `Arc` is recommended for
-  non-trivial data types.
-  - The one exception to those rules is the `ty::steal::Steal` type,
-    which is used to cheaply modify MIR in place. See the definition
-    of `Steal` for more details. New uses of `Steal` should **not** be
-    added without alerting `@rust-lang/compiler`.
-
-So, to add a query:
-
-- Add an entry to `define_queries!` using the format above.
-- Possibly add a corresponding entry to the dep-node macro.
-- Link the provider by modifying the appropriate `provide` method;
-  or add a new one if needed and ensure that `rustc_driver` is invoking it.
-
-#### Query structs and descriptions
-
-For each kind, the `define_queries` macro will generate a "query struct"
-named after the query. This struct is a kind of a place-holder
-describing the query. Each such struct implements the
-`self::config::QueryConfig` trait, which has associated types for the
-key/value of that particular query. Basically the code generated looks something
-like this:
-
-```rust
-// Dummy struct representing a particular kind of query:
-pub struct type_of<'tcx> { phantom: PhantomData<&'tcx ()> }
-
-impl<'tcx> QueryConfig for type_of<'tcx> {
-  type Key = DefId;
-  type Value = Ty<'tcx>;
-}
-```
-
-There is an additional trait that you may wish to implement called
-`self::config::QueryDescription`. This trait is used during cycle
-errors to give a "human readable" name for the query, so that we can
-summarize what was happening when the cycle occurred. Implementing
-this trait is optional if the query key is `DefId`, but if you *don't*
-implement it, you get a pretty generic error ("processing `foo`...").
-You can put new impls into the `config` module. They look something like this:
-
-```rust
-impl<'tcx> QueryDescription for queries::type_of<'tcx> {
-    fn describe(tcx: TyCtxt<'_, '_, '_>, key: DefId) -> String {
-        format!("computing the type of `{}`", tcx.item_path_str(key))
-    }
-}
-```
+For more information about how the query system works, see the [rustc guide].
 
+[rustc guide]: https://rust-lang.github.io/rustc-guide/query.html
diff --git a/src/librustc/ty/query/config.rs b/src/librustc/ty/query/config.rs
index ca5d1f6bd3203..1870812893c14 100644
--- a/src/librustc/ty/query/config.rs
+++ b/src/librustc/ty/query/config.rs
@@ -1,27 +1,28 @@
-use dep_graph::SerializedDepNodeIndex;
-use dep_graph::DepNode;
-use hir::def_id::{CrateNum, DefId, DefIndex};
-use mir::interpret::GlobalId;
-use traits;
-use traits::query::{
+use crate::dep_graph::SerializedDepNodeIndex;
+use crate::dep_graph::DepNode;
+use crate::hir::def_id::{CrateNum, DefId, DefIndex};
+use crate::mir::interpret::GlobalId;
+use crate::traits;
+use crate::traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
     CanonicalTypeOpAscribeUserTypeGoal, CanonicalTypeOpEqGoal, CanonicalTypeOpNormalizeGoal,
     CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpSubtypeGoal,
 };
-use ty::{self, ParamEnvAnd, Ty, TyCtxt};
-use ty::subst::Substs;
-use ty::query::queries;
-use ty::query::Query;
-use ty::query::QueryCache;
-use util::profiling::ProfileCategory;
+use crate::ty::{self, ParamEnvAnd, Ty, TyCtxt};
+use crate::ty::subst::Substs;
+use crate::ty::query::queries;
+use crate::ty::query::Query;
+use crate::ty::query::QueryCache;
+use crate::ty::query::plumbing::CycleError;
+use crate::util::profiling::ProfileCategory;
 
 use std::borrow::Cow;
 use std::hash::Hash;
 use std::fmt::Debug;
 use syntax_pos::symbol::InternedString;
 use rustc_data_structures::sync::Lock;
-use rustc_data_structures::stable_hasher::HashStable;
-use ich::StableHashingContext;
+use rustc_data_structures::fingerprint::Fingerprint;
+use crate::ich::StableHashingContext;
 
 // Query configuration and description traits.
 
@@ -30,7 +31,7 @@ pub trait QueryConfig<'tcx> {
     const CATEGORY: ProfileCategory;
 
     type Key: Eq + Hash + Clone + Debug;
-    type Value: Clone + for<'a> HashStable<StableHashingContext<'a>>;
+    type Value: Clone;
 }
 
 pub(super) trait QueryAccessors<'tcx>: QueryConfig<'tcx> {
@@ -44,14 +45,19 @@ pub(super) trait QueryAccessors<'tcx>: QueryConfig<'tcx> {
     // Don't use this method to compute query results, instead use the methods on TyCtxt
     fn compute(tcx: TyCtxt<'_, 'tcx, '_>, key: Self::Key) -> Self::Value;
 
-    fn handle_cycle_error(tcx: TyCtxt<'_, 'tcx, '_>) -> Self::Value;
+    fn hash_result(
+        hcx: &mut StableHashingContext<'_>,
+        result: &Self::Value
+    ) -> Option<Fingerprint>;
+
+    fn handle_cycle_error(tcx: TyCtxt<'_, 'tcx, '_>, error: CycleError<'tcx>) -> Self::Value;
 }
 
 pub(super) trait QueryDescription<'tcx>: QueryAccessors<'tcx> {
     fn describe(tcx: TyCtxt<'_, '_, '_>, key: Self::Key) -> Cow<'static, str>;
 
     #[inline]
-    fn cache_on_disk(_: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _: Self::Key) -> bool {
         false
     }
 
@@ -109,6 +115,42 @@ impl<'tcx> QueryDescription<'tcx> for queries::check_mod_item_types<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription<'tcx> for queries::check_mod_privacy<'tcx> {
+    fn describe(
+        tcx: TyCtxt<'_, '_, '_>,
+        key: DefId,
+    ) -> Cow<'static, str> {
+        format!("checking privacy in {}", key.describe_as_module(tcx)).into()
+    }
+}
+
+impl<'tcx> QueryDescription<'tcx> for queries::check_mod_intrinsics<'tcx> {
+    fn describe(
+        tcx: TyCtxt<'_, '_, '_>,
+        key: DefId,
+    ) -> Cow<'static, str> {
+        format!("checking intrinsics in {}", key.describe_as_module(tcx)).into()
+    }
+}
+
+impl<'tcx> QueryDescription<'tcx> for queries::check_mod_liveness<'tcx> {
+    fn describe(
+        tcx: TyCtxt<'_, '_, '_>,
+        key: DefId,
+    ) -> Cow<'static, str> {
+        format!("checking liveness of variables in {}", key.describe_as_module(tcx)).into()
+    }
+}
+
+impl<'tcx> QueryDescription<'tcx> for queries::check_mod_impl_wf<'tcx> {
+    fn describe(
+        tcx: TyCtxt<'_, '_, '_>,
+        key: DefId,
+    ) -> Cow<'static, str> {
+        format!("checking that impls are well-formed in {}", key.describe_as_module(tcx)).into()
+    }
+}
+
 impl<'tcx> QueryDescription<'tcx> for queries::collect_mod_item_types<'tcx> {
     fn describe(
         tcx: TyCtxt<'_, '_, '_>,
@@ -351,7 +393,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::const_eval<'tcx> {
     }
 
     #[inline]
-    fn cache_on_disk(_key: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _key: Self::Key) -> bool {
         true
     }
 
@@ -371,7 +413,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::const_eval_raw<'tcx> {
     }
 
     #[inline]
-    fn cache_on_disk(_key: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _key: Self::Key) -> bool {
         true
     }
 
@@ -395,7 +437,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::symbol_name<'tcx> {
     }
 
     #[inline]
-    fn cache_on_disk(_: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _: Self::Key) -> bool {
         true
     }
 
@@ -469,7 +511,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::const_is_rvalue_promotable_to_sta
     }
 
     #[inline]
-    fn cache_on_disk(_: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _: Self::Key) -> bool {
         true
     }
 
@@ -503,7 +545,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::codegen_fulfill_obligation<'tcx>
     }
 
     #[inline]
-    fn cache_on_disk(_: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, _: Self::Key) -> bool {
         true
     }
 
@@ -629,6 +671,12 @@ impl<'tcx> QueryDescription<'tcx> for queries::foreign_modules<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription<'tcx> for queries::entry_fn<'tcx> {
+    fn describe(_tcx: TyCtxt<'_, '_, '_>, _: CrateNum) -> Cow<'static, str> {
+        "looking up the entry function of a crate".into()
+    }
+}
+
 impl<'tcx> QueryDescription<'tcx> for queries::plugin_registrar_fn<'tcx> {
     fn describe(_tcx: TyCtxt<'_, '_, '_>, _: CrateNum) -> Cow<'static, str> {
         "looking up the plugin registrar for a crate".into()
@@ -835,7 +883,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::features_query<'tcx> {
 
 impl<'tcx> QueryDescription<'tcx> for queries::typeck_tables_of<'tcx> {
     #[inline]
-    fn cache_on_disk(def_id: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, def_id: Self::Key) -> bool {
         def_id.is_local()
     }
 
@@ -852,14 +900,14 @@ impl<'tcx> QueryDescription<'tcx> for queries::typeck_tables_of<'tcx> {
 
 impl<'tcx> QueryDescription<'tcx> for queries::optimized_mir<'tcx> {
     #[inline]
-    fn cache_on_disk(def_id: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, def_id: Self::Key) -> bool {
         def_id.is_local()
     }
 
     fn try_load_from_disk<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                               id: SerializedDepNodeIndex)
                               -> Option<Self::Value> {
-        let mir: Option<::mir::Mir<'tcx>> = tcx.queries.on_disk_cache
+        let mir: Option<crate::mir::Mir<'tcx>> = tcx.queries.on_disk_cache
                                                .try_load_query_result(tcx, id);
         mir.map(|x| tcx.alloc_mir(x))
     }
@@ -891,7 +939,7 @@ impl<'tcx> QueryDescription<'tcx> for queries::instance_def_size_estimate<'tcx>
 
 impl<'tcx> QueryDescription<'tcx> for queries::generics_of<'tcx> {
     #[inline]
-    fn cache_on_disk(def_id: Self::Key) -> bool {
+    fn cache_on_disk(_: TyCtxt<'_, 'tcx, 'tcx>, def_id: Self::Key) -> bool {
         def_id.is_local()
     }
 
@@ -934,11 +982,17 @@ impl<'tcx> QueryDescription<'tcx> for queries::dllimport_foreign_items<'tcx> {
     }
 }
 
+impl<'tcx> QueryDescription<'tcx> for queries::backend_optimization_level<'tcx> {
+    fn describe(_tcx: TyCtxt<'_, '_, '_>, _: CrateNum) -> Cow<'static, str> {
+        "optimization level used by backend".into()
+    }
+}
+
 macro_rules! impl_disk_cacheable_query(
-    ($query_name:ident, |$key:tt| $cond:expr) => {
+    ($query_name:ident, |$tcx:tt, $key:tt| $cond:expr) => {
         impl<'tcx> QueryDescription<'tcx> for queries::$query_name<'tcx> {
             #[inline]
-            fn cache_on_disk($key: Self::Key) -> bool {
+            fn cache_on_disk($tcx: TyCtxt<'_, 'tcx, 'tcx>, $key: Self::Key) -> bool {
                 $cond
             }
 
@@ -952,14 +1006,17 @@ macro_rules! impl_disk_cacheable_query(
     }
 );
 
-impl_disk_cacheable_query!(unsafety_check_result, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(borrowck, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(mir_borrowck, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(mir_const_qualif, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(check_match, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(def_symbol_name, |_| true);
-impl_disk_cacheable_query!(type_of, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(predicates_of, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(used_trait_imports, |def_id| def_id.is_local());
-impl_disk_cacheable_query!(codegen_fn_attrs, |_| true);
-impl_disk_cacheable_query!(specialization_graph_of, |_| true);
+impl_disk_cacheable_query!(mir_borrowck, |tcx, def_id| {
+    def_id.is_local() && tcx.is_closure(def_id)
+});
+
+impl_disk_cacheable_query!(unsafety_check_result, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(borrowck, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(mir_const_qualif, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(check_match, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(def_symbol_name, |_, _| true);
+impl_disk_cacheable_query!(type_of, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(predicates_of, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(used_trait_imports, |_, def_id| def_id.is_local());
+impl_disk_cacheable_query!(codegen_fn_attrs, |_, _| true);
+impl_disk_cacheable_query!(specialization_graph_of, |_, _| true);
diff --git a/src/librustc/ty/query/job.rs b/src/librustc/ty/query/job.rs
index d794429a8a706..22211468412c1 100644
--- a/src/librustc/ty/query/job.rs
+++ b/src/librustc/ty/query/job.rs
@@ -1,25 +1,27 @@
 #![allow(warnings)]
 
 use std::mem;
+use std::process;
+use std::{fmt, ptr};
+
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::{Lock, LockGuard, Lrc, Weak};
 use rustc_data_structures::OnDrop;
 use syntax_pos::Span;
-use ty::tls;
-use ty::query::Query;
-use ty::query::plumbing::CycleError;
-#[cfg(not(parallel_queries))]
-use ty::query::{
+
+use crate::ty::tls;
+use crate::ty::query::Query;
+use crate::ty::query::plumbing::CycleError;
+#[cfg(not(parallel_compiler))]
+use crate::ty::query::{
     plumbing::TryGetJob,
     config::QueryDescription,
 };
-use ty::context::TyCtxt;
-use std::process;
-use std::{fmt, ptr};
+use crate::ty::context::TyCtxt;
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 use {
-    rayon_core,
+    rustc_rayon_core as rayon_core,
     parking_lot::{Mutex, Condvar},
     std::sync::atomic::Ordering,
     std::thread,
@@ -29,71 +31,54 @@ use {
     rustc_data_structures::stable_hasher::{StableHasherResult, StableHasher, HashStable},
 };
 
-/// Indicates the state of a query for a given key in a query map
+/// Indicates the state of a query for a given key in a query map.
 pub(super) enum QueryResult<'tcx> {
-    /// An already executing query. The query job can be used to await for its completion
+    /// An already executing query. The query job can be used to await for its completion.
     Started(Lrc<QueryJob<'tcx>>),
 
-    /// The query panicked. Queries trying to wait on this will raise a fatal error / silently panic
+    /// The query panicked. Queries trying to wait on this will raise a fatal error or
+    /// silently panic.
     Poisoned,
 }
 
-/// A span and a query key
+/// Represents a span and a query key.
 #[derive(Clone, Debug)]
 pub struct QueryInfo<'tcx> {
-    /// The span for a reason this query was required
+    /// The span corresponding to the reason for which this query was required.
     pub span: Span,
     pub query: Query<'tcx>,
 }
 
-/// A object representing an active query job.
+/// Representss an object representing an active query job.
 pub struct QueryJob<'tcx> {
     pub info: QueryInfo<'tcx>,
 
     /// The parent query job which created this job and is implicitly waiting on it.
     pub parent: Option<Lrc<QueryJob<'tcx>>>,
 
-    /// The latch which is used to wait on this job
-    #[cfg(parallel_queries)]
+    /// The latch that is used to wait on this job.
+    #[cfg(parallel_compiler)]
     latch: QueryLatch<'tcx>,
 }
 
 impl<'tcx> QueryJob<'tcx> {
-    /// Creates a new query job
+    /// Creates a new query job.
     pub fn new(info: QueryInfo<'tcx>, parent: Option<Lrc<QueryJob<'tcx>>>) -> Self {
         QueryJob {
             info,
             parent,
-            #[cfg(parallel_queries)]
+            #[cfg(parallel_compiler)]
             latch: QueryLatch::new(),
         }
     }
 
     /// Awaits for the query job to complete.
-    ///
-    /// For single threaded rustc there's no concurrent jobs running, so if we are waiting for any
-    /// query that means that there is a query cycle, thus this always running a cycle error.
-    #[cfg(not(parallel_queries))]
-    #[inline(never)]
-    #[cold]
-    pub(super) fn cycle_error<'lcx, 'a, D: QueryDescription<'tcx>>(
-        &self,
-        tcx: TyCtxt<'_, 'tcx, 'lcx>,
-        span: Span,
-    ) -> TryGetJob<'a, 'tcx, D> {
-        TryGetJob::JobCompleted(Err(Box::new(self.find_cycle_in_stack(tcx, span))))
-    }
-
-    /// Awaits for the query job to complete.
-    ///
-    /// For single threaded rustc there's no concurrent jobs running, so if we are waiting for any
-    /// query that means that there is a query cycle, thus this always running a cycle error.
-    #[cfg(parallel_queries)]
-    pub(super) fn await<'lcx>(
+    #[cfg(parallel_compiler)]
+    pub(super) fn r#await<'lcx>(
         &self,
         tcx: TyCtxt<'_, 'tcx, 'lcx>,
         span: Span,
-    ) -> Result<(), Box<CycleError<'tcx>>> {
+    ) -> Result<(), CycleError<'tcx>> {
         tls::with_related_context(tcx, move |icx| {
             let mut waiter = Lrc::new(QueryWaiter {
                 query: icx.query.clone(),
@@ -101,20 +86,20 @@ impl<'tcx> QueryJob<'tcx> {
                 cycle: Lock::new(None),
                 condvar: Condvar::new(),
             });
-            self.latch.await(&waiter);
+            self.latch.r#await(&waiter);
             // FIXME: Get rid of this lock. We have ownership of the QueryWaiter
             // although another thread may still have a Lrc reference so we cannot
             // use Lrc::get_mut
             let mut cycle = waiter.cycle.lock();
             match cycle.take() {
                 None => Ok(()),
-                Some(cycle) => Err(Box::new(cycle))
+                Some(cycle) => Err(cycle)
             }
         })
     }
 
-    #[cfg(not(parallel_queries))]
-    fn find_cycle_in_stack<'lcx>(
+    #[cfg(not(parallel_compiler))]
+    pub(super) fn find_cycle_in_stack<'lcx>(
         &self,
         tcx: TyCtxt<'_, 'tcx, 'lcx>,
         span: Span,
@@ -152,7 +137,7 @@ impl<'tcx> QueryJob<'tcx> {
     /// This does nothing for single threaded rustc,
     /// as there are no concurrent jobs which could be waiting on us
     pub fn signal_complete(&self) {
-        #[cfg(parallel_queries)]
+        #[cfg(parallel_compiler)]
         self.latch.set();
     }
 
@@ -161,7 +146,7 @@ impl<'tcx> QueryJob<'tcx> {
     }
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 struct QueryWaiter<'tcx> {
     query: Option<Lrc<QueryJob<'tcx>>>,
     condvar: Condvar,
@@ -169,7 +154,7 @@ struct QueryWaiter<'tcx> {
     cycle: Lock<Option<CycleError<'tcx>>>,
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 impl<'tcx> QueryWaiter<'tcx> {
     fn notify(&self, registry: &rayon_core::Registry) {
         rayon_core::mark_unblocked(registry);
@@ -177,18 +162,18 @@ impl<'tcx> QueryWaiter<'tcx> {
     }
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 struct QueryLatchInfo<'tcx> {
     complete: bool,
     waiters: Vec<Lrc<QueryWaiter<'tcx>>>,
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 struct QueryLatch<'tcx> {
     info: Mutex<QueryLatchInfo<'tcx>>,
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 impl<'tcx> QueryLatch<'tcx> {
     fn new() -> Self {
         QueryLatch {
@@ -200,7 +185,7 @@ impl<'tcx> QueryLatch<'tcx> {
     }
 
     /// Awaits the caller on this latch by blocking the current thread.
-    fn await(&self, waiter: &Lrc<QueryWaiter<'tcx>>) {
+    fn r#await(&self, waiter: &Lrc<QueryWaiter<'tcx>>) {
         let mut info = self.info.lock();
         if !info.complete {
             // We push the waiter on to the `waiters` list. It can be accessed inside
@@ -228,7 +213,7 @@ impl<'tcx> QueryLatch<'tcx> {
         }
     }
 
-    /// Remove a single waiter from the list of waiters.
+    /// Removes a single waiter from the list of waiters.
     /// This is used to break query cycles.
     fn extract_waiter(
         &self,
@@ -242,7 +227,7 @@ impl<'tcx> QueryLatch<'tcx> {
 }
 
 /// A resumable waiter of a query. The usize is the index into waiters in the query's latch
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 type Waiter<'tcx> = (Lrc<QueryJob<'tcx>>, usize);
 
 /// Visits all the non-resumable and resumable waiters of a query.
@@ -254,7 +239,7 @@ type Waiter<'tcx> = (Lrc<QueryJob<'tcx>>, usize);
 /// For visits of resumable waiters it returns Some(Some(Waiter)) which has the
 /// required information to resume the waiter.
 /// If all `visit` calls returns None, this function also returns None.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn visit_waiters<'tcx, F>(query: Lrc<QueryJob<'tcx>>, mut visit: F) -> Option<Option<Waiter<'tcx>>>
 where
     F: FnMut(Span, Lrc<QueryJob<'tcx>>) -> Option<Option<Waiter<'tcx>>>
@@ -282,7 +267,7 @@ where
 /// `span` is the reason for the `query` to execute. This is initially DUMMY_SP.
 /// If a cycle is detected, this initial value is replaced with the span causing
 /// the cycle.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn cycle_check<'tcx>(query: Lrc<QueryJob<'tcx>>,
                      span: Span,
                      stack: &mut Vec<(Span, Lrc<QueryJob<'tcx>>)>,
@@ -321,7 +306,7 @@ fn cycle_check<'tcx>(query: Lrc<QueryJob<'tcx>>,
 /// Finds out if there's a path to the compiler root (aka. code which isn't in a query)
 /// from `query` without going through any of the queries in `visited`.
 /// This is achieved with a depth first search.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn connected_to_root<'tcx>(
     query: Lrc<QueryJob<'tcx>>,
     visited: &mut FxHashSet<*const QueryJob<'tcx>>
@@ -346,7 +331,7 @@ fn connected_to_root<'tcx>(
 }
 
 // Deterministically pick an query from a list
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn pick_query<'a, 'tcx, T, F: Fn(&T) -> (Span, Lrc<QueryJob<'tcx>>)>(
     tcx: TyCtxt<'_, 'tcx, '_>,
     queries: &'a [T],
@@ -372,7 +357,7 @@ fn pick_query<'a, 'tcx, T, F: Fn(&T) -> (Span, Lrc<QueryJob<'tcx>>)>(
 /// the function return true.
 /// If a cycle was not found, the starting query is removed from `jobs` and
 /// the function returns false.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn remove_cycle<'tcx>(
     jobs: &mut Vec<Lrc<QueryJob<'tcx>>>,
     wakelist: &mut Vec<Lrc<QueryWaiter<'tcx>>>,
@@ -475,7 +460,7 @@ fn remove_cycle<'tcx>(
 /// Creates a new thread and forwards information in thread locals to it.
 /// The new thread runs the deadlock handler.
 /// Must only be called when a deadlock is about to happen.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 pub unsafe fn handle_deadlock() {
     use syntax;
     use syntax_pos;
@@ -514,7 +499,7 @@ pub unsafe fn handle_deadlock() {
 /// uses a query latch and then resuming that waiter.
 /// There may be multiple cycles involved in a deadlock, so this searches
 /// all active queries for cycles before finally resuming all the waiters at once.
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 fn deadlock(tcx: TyCtxt<'_, '_, '_>, registry: &rayon_core::Registry) {
     let on_panic = OnDrop(|| {
         eprintln!("deadlock handler panicked, aborting process");
diff --git a/src/librustc/ty/query/keys.rs b/src/librustc/ty/query/keys.rs
index af6f5a00dee5c..f5eb7374cc19b 100644
--- a/src/librustc/ty/query/keys.rs
+++ b/src/librustc/ty/query/keys.rs
@@ -1,12 +1,12 @@
 //! Defines the set of legal keys that can be used in queries.
 
-use infer::canonical::Canonical;
-use hir::def_id::{CrateNum, DefId, LOCAL_CRATE, DefIndex};
-use traits;
-use ty::{self, Ty, TyCtxt};
-use ty::subst::Substs;
-use ty::fast_reject::SimplifiedType;
-use mir;
+use crate::infer::canonical::Canonical;
+use crate::hir::def_id::{CrateNum, DefId, LOCAL_CRATE, DefIndex};
+use crate::traits;
+use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::subst::Substs;
+use crate::ty::fast_reject::SimplifiedType;
+use crate::mir;
 
 use std::fmt::Debug;
 use std::hash::Hash;
diff --git a/src/librustc/ty/query/mod.rs b/src/librustc/ty/query/mod.rs
index 39d76ceed9507..740875109d029 100644
--- a/src/librustc/ty/query/mod.rs
+++ b/src/librustc/ty/query/mod.rs
@@ -1,54 +1,55 @@
-use dep_graph::{DepConstructor, DepNode};
-use errors::DiagnosticBuilder;
-use hir::def_id::{CrateNum, DefId, DefIndex};
-use hir::def::{Def, Export};
-use hir::{self, TraitCandidate, ItemLocalId, CodegenFnAttrs};
-use rustc_data_structures::svh::Svh;
-use infer::canonical::{self, Canonical};
-use lint;
-use middle::borrowck::BorrowCheckResult;
-use middle::cstore::{ExternCrate, LinkagePreference, NativeLibrary, ForeignModule};
-use middle::cstore::{NativeLibraryKind, DepKind, CrateSource};
-use middle::privacy::AccessLevels;
-use middle::reachable::ReachableSet;
-use middle::region;
-use middle::resolve_lifetime::{ResolveLifetimes, Region, ObjectLifetimeDefault};
-use middle::stability::{self, DeprecationEntry};
-use middle::lib_features::LibFeatures;
-use middle::lang_items::{LanguageItems, LangItem};
-use middle::exported_symbols::{SymbolExportLevel, ExportedSymbol};
-use mir::interpret::{ConstEvalRawResult, ConstEvalResult};
-use mir::mono::CodegenUnit;
-use mir;
-use mir::interpret::GlobalId;
-use session::{CompileResult, CrateDisambiguator};
-use session::config::OutputFilenames;
-use traits::{self, Vtable};
-use traits::query::{
+use crate::dep_graph::{self, DepConstructor, DepNode};
+use crate::hir::def_id::{CrateNum, DefId, DefIndex};
+use crate::hir::def::{Def, Export};
+use crate::hir::{self, TraitCandidate, ItemLocalId, CodegenFnAttrs};
+use crate::infer::canonical::{self, Canonical};
+use crate::lint;
+use crate::middle::borrowck::BorrowCheckResult;
+use crate::middle::cstore::{ExternCrate, LinkagePreference, NativeLibrary, ForeignModule};
+use crate::middle::cstore::{NativeLibraryKind, DepKind, CrateSource};
+use crate::middle::privacy::AccessLevels;
+use crate::middle::reachable::ReachableSet;
+use crate::middle::region;
+use crate::middle::resolve_lifetime::{ResolveLifetimes, Region, ObjectLifetimeDefault};
+use crate::middle::stability::{self, DeprecationEntry};
+use crate::middle::lib_features::LibFeatures;
+use crate::middle::lang_items::{LanguageItems, LangItem};
+use crate::middle::exported_symbols::{SymbolExportLevel, ExportedSymbol};
+use crate::mir::interpret::{ConstEvalRawResult, ConstEvalResult};
+use crate::mir::mono::CodegenUnit;
+use crate::mir;
+use crate::mir::interpret::GlobalId;
+use crate::session::{CompileResult, CrateDisambiguator};
+use crate::session::config::{EntryFnType, OutputFilenames, OptLevel};
+use crate::traits::{self, Vtable};
+use crate::traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal,
     CanonicalTyGoal, CanonicalTypeOpAscribeUserTypeGoal,
     CanonicalTypeOpEqGoal, CanonicalTypeOpSubtypeGoal, CanonicalTypeOpProvePredicateGoal,
     CanonicalTypeOpNormalizeGoal, NoSolution,
 };
-use traits::query::method_autoderef::MethodAutoderefStepsResult;
-use traits::query::dropck_outlives::{DtorckConstraint, DropckOutlivesResult};
-use traits::query::normalize::NormalizationResult;
-use traits::query::outlives_bounds::OutlivesBound;
-use traits::specialization_graph;
-use traits::Clauses;
-use ty::{self, CrateInherentImpls, ParamEnvAnd, Ty, TyCtxt};
-use ty::steal::Steal;
-use ty::subst::Substs;
-use util::nodemap::{DefIdSet, DefIdMap, ItemLocalSet};
-use util::common::{ErrorReported};
-use util::profiling::ProfileCategory::*;
-use session::Session;
+use crate::traits::query::method_autoderef::MethodAutoderefStepsResult;
+use crate::traits::query::dropck_outlives::{DtorckConstraint, DropckOutlivesResult};
+use crate::traits::query::normalize::NormalizationResult;
+use crate::traits::query::outlives_bounds::OutlivesBound;
+use crate::traits::specialization_graph;
+use crate::traits::Clauses;
+use crate::ty::{self, CrateInherentImpls, ParamEnvAnd, Ty, TyCtxt, AdtSizedConstraint};
+use crate::ty::steal::Steal;
+use crate::ty::subst::Substs;
+use crate::ty::util::NeedsDrop;
+use crate::util::nodemap::{DefIdSet, DefIdMap, ItemLocalSet};
+use crate::util::common::{ErrorReported};
+use crate::util::profiling::ProfileCategory::*;
+use crate::session::Session;
 
+use rustc_data_structures::svh::Svh;
 use rustc_data_structures::bit_set::BitSet;
 use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::stable_hasher::StableVec;
 use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_target::spec::PanicStrategy;
 
 use std::borrow::Cow;
@@ -69,7 +70,7 @@ pub use self::plumbing::{force_from_dep_node, CycleError};
 
 mod job;
 pub use self::job::{QueryJob, QueryInfo};
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 pub use self::job::handle_deadlock;
 
 mod keys;
@@ -101,12 +102,12 @@ define_queries! { <'tcx>
         /// Records the type of every item.
         [] fn type_of: TypeOfItem(DefId) -> Ty<'tcx>,
 
-        /// Maps from the def-id of an item (trait/struct/enum/fn) to its
+        /// Maps from the `DefId` of an item (trait/struct/enum/fn) to its
         /// associated generics.
         [] fn generics_of: GenericsOfItem(DefId) -> &'tcx ty::Generics,
 
-        /// Maps from the def-id of an item (trait/struct/enum/fn) to the
-        /// predicates (where clauses) that must be proven true in order
+        /// Maps from the `DefId` of an item (trait/struct/enum/fn) to the
+        /// predicates (where-clauses) that must be proven true in order
         /// to reference it. This is almost always the "predicates query"
         /// that you want.
         ///
@@ -122,8 +123,8 @@ define_queries! { <'tcx>
         /// user.)
         [] fn predicates_of: PredicatesOfItem(DefId) -> Lrc<ty::GenericPredicates<'tcx>>,
 
-        /// Maps from the def-id of an item (trait/struct/enum/fn) to the
-        /// predicates (where clauses) directly defined on it. This is
+        /// Maps from the `DefId` of an item (trait/struct/enum/fn) to the
+        /// predicates (where-clauses) directly defined on it. This is
         /// equal to the `explicit_predicates_of` predicates plus the
         /// `inferred_outlives_of` predicates.
         [] fn predicates_defined_on: PredicatesDefinedOnItem(DefId)
@@ -137,7 +138,7 @@ define_queries! { <'tcx>
         /// Foo<'a, T> { x: &'a T }`, this would return `T: 'a`).
         [] fn inferred_outlives_of: InferredOutlivesOf(DefId) -> Lrc<Vec<ty::Predicate<'tcx>>>,
 
-        /// Maps from the def-id of a trait to the list of
+        /// Maps from the `DefId` of a trait to the list of
         /// super-predicates. This is a subset of the full list of
         /// predicates. We store these in a separate map because we must
         /// evaluate them even during type conversion, often before the
@@ -153,7 +154,16 @@ define_queries! { <'tcx>
         [] fn trait_def: TraitDefOfItem(DefId) -> &'tcx ty::TraitDef,
         [] fn adt_def: AdtDefOfItem(DefId) -> &'tcx ty::AdtDef,
         [] fn adt_destructor: AdtDestructor(DefId) -> Option<ty::Destructor>,
-        [] fn adt_sized_constraint: SizedConstraint(DefId) -> &'tcx [Ty<'tcx>],
+
+        // The cycle error here should be reported as an error by `check_representable`.
+        // We consider the type as Sized in the meanwhile to avoid
+        // further errors (done in impl Value for AdtSizedConstraint).
+        // Use `cycle_delay_bug` to delay the cycle error here to be emitted later
+        // in case we accidentally otherwise don't emit an error.
+        [cycle_delay_bug] fn adt_sized_constraint: SizedConstraint(
+            DefId
+        ) -> AdtSizedConstraint<'tcx>,
+
         [] fn adt_dtorck_constraint: DtorckConstraint(
             DefId
         ) -> Result<DtorckConstraint<'tcx>, NoSolution>,
@@ -215,7 +225,7 @@ define_queries! { <'tcx>
     },
 
     Codegen {
-        /// Set of all the def-ids in this crate that have MIR associated with
+        /// Set of all the `DefId`s in this crate that have MIR associated with
         /// them. This includes all the body owners, but also things like struct
         /// constructors.
         [] fn mir_keys: mir_keys(CrateNum) -> Lrc<DefIdSet>,
@@ -225,17 +235,17 @@ define_queries! { <'tcx>
         /// the value isn't known except to the pass itself.
         [] fn mir_const_qualif: MirConstQualif(DefId) -> (u8, Lrc<BitSet<mir::Local>>),
 
-        /// Fetch the MIR for a given def-id right after it's built - this includes
+        /// Fetch the MIR for a given `DefId` right after it's built - this includes
         /// unreachable code.
         [] fn mir_built: MirBuilt(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
 
-        /// Fetch the MIR for a given def-id up till the point where it is
+        /// Fetch the MIR for a given `DefId` up till the point where it is
         /// ready for const evaluation.
         ///
         /// See the README for the `mir` module for details.
-        [] fn mir_const: MirConst(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
+        [no_hash] fn mir_const: MirConst(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
 
-        [] fn mir_validated: MirValidated(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
+        [no_hash] fn mir_validated: MirValidated(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
 
         /// MIR after our optimization passes have run. This is MIR that is ready
         /// for codegen. This is also the only query that can fetch non-local MIR, at present.
@@ -243,7 +253,7 @@ define_queries! { <'tcx>
     },
 
     TypeChecking {
-        /// The result of unsafety-checking this def-id.
+        /// The result of unsafety-checking this `DefId`.
         [] fn unsafety_check_result: UnsafetyCheckResult(DefId) -> mir::UnsafetyCheckResult,
 
         /// HACK: when evaluated, this reports a "unsafe derive on repr(packed)" error
@@ -264,6 +274,14 @@ define_queries! { <'tcx>
 
         [] fn check_mod_item_types: CheckModItemTypes(DefId) -> (),
 
+        [] fn check_mod_privacy: CheckModPrivacy(DefId) -> (),
+
+        [] fn check_mod_intrinsics: CheckModIntrinsics(DefId) -> (),
+
+        [] fn check_mod_liveness: CheckModLiveness(DefId) -> (),
+
+        [] fn check_mod_impl_wf: CheckModImplWf(DefId) -> (),
+
         [] fn collect_mod_item_types: CollectModItemTypes(DefId) -> (),
 
         /// Caches CoerceUnsized kinds for impls on custom types.
@@ -298,13 +316,13 @@ define_queries! { <'tcx>
     TypeChecking {
         /// Gets a complete map from all types to their inherent impls.
         /// Not meant to be used directly outside of coherence.
-        /// (Defined only for LOCAL_CRATE)
+        /// (Defined only for `LOCAL_CRATE`.)
         [] fn crate_inherent_impls: crate_inherent_impls_dep_node(CrateNum)
             -> Lrc<CrateInherentImpls>,
 
-        /// Checks all types in the krate for overlap in their inherent impls. Reports errors.
+        /// Checks all types in the crate for overlap in their inherent impls. Reports errors.
         /// Not meant to be used directly outside of coherence.
-        /// (Defined only for LOCAL_CRATE)
+        /// (Defined only for `LOCAL_CRATE`.)
         [] fn crate_inherent_impls_overlap_check: inherent_impls_overlap_check_dep_node(CrateNum)
             -> (),
     },
@@ -312,9 +330,9 @@ define_queries! { <'tcx>
     Other {
         /// Evaluate a constant without running sanity checks
         ///
-        /// DO NOT USE THIS outside const eval. Const eval uses this to break query cycles during
-        /// validation. Please add a comment to every use site explaining why using `const_eval`
-        /// isn't sufficient
+        /// **Do not use this** outside const eval. Const eval uses this to break query cycles
+        /// during validation. Please add a comment to every use site explaining why using
+        /// `const_eval` isn't sufficient
         [] fn const_eval_raw: const_eval_raw_dep_node(ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>)
             -> ConstEvalRawResult<'tcx>,
 
@@ -335,7 +353,7 @@ define_queries! { <'tcx>
     Other {
         [] fn reachable_set: reachability_dep_node(CrateNum) -> ReachableSet,
 
-        /// Per-body `region::ScopeTree`. The `DefId` should be the owner-def-id for the body;
+        /// Per-body `region::ScopeTree`. The `DefId` should be the owner `DefId` for the body;
         /// in the case of closures, this will be redirected to the enclosing function.
         [] fn region_scope_tree: RegionScopeTree(DefId) -> Lrc<region::ScopeTree>,
 
@@ -389,7 +407,7 @@ define_queries! { <'tcx>
             -> Lrc<specialization_graph::Graph>,
         [] fn is_object_safe: ObjectSafety(DefId) -> bool,
 
-        /// Get the ParameterEnvironment for a given item; this environment
+        /// Gets the ParameterEnvironment for a given item; this environment
         /// will be in "user-facing" mode, meaning that it is suitabe for
         /// type-checking etc, and it does not normalize specializable
         /// associated types. This is almost always what you want,
@@ -402,7 +420,16 @@ define_queries! { <'tcx>
         [] fn is_copy_raw: is_copy_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
         [] fn is_sized_raw: is_sized_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
         [] fn is_freeze_raw: is_freeze_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
-        [] fn needs_drop_raw: needs_drop_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
+
+        // The cycle error here should be reported as an error by `check_representable`.
+        // We consider the type as not needing drop in the meanwhile to avoid
+        // further errors (done in impl Value for NeedsDrop).
+        // Use `cycle_delay_bug` to delay the cycle error here to be emitted later
+        // in case we accidentally otherwise don't emit an error.
+        [cycle_delay_bug] fn needs_drop_raw: needs_drop_dep_node(
+            ty::ParamEnvAnd<'tcx, Ty<'tcx>>
+        ) -> NeedsDrop,
+
         [] fn layout_raw: layout_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>)
                                     -> Result<&'tcx ty::layout::LayoutDetails,
                                                 ty::layout::LayoutError<'tcx>>,
@@ -476,6 +503,9 @@ define_queries! { <'tcx>
 
         [] fn foreign_modules: ForeignModules(CrateNum) -> Lrc<Vec<ForeignModule>>,
 
+        /// Identifies the entry-point (e.g., the `main` function) for a given
+        /// crate, returning `None` if there is no entry point (such as for library crates).
+        [] fn entry_fn: EntryFn(CrateNum) -> Option<(DefId, EntryFnType)>,
         [] fn plugin_registrar_fn: PluginRegistrarFn(CrateNum) -> Option<DefId>,
         [] fn proc_macro_decls_static: ProcMacroDeclsStatic(CrateNum) -> Option<DefId>,
         [] fn crate_disambiguator: CrateDisambiguator(CrateNum) -> CrateDisambiguator,
@@ -541,6 +571,8 @@ define_queries! { <'tcx>
         [] fn maybe_unused_trait_import: MaybeUnusedTraitImport(DefId) -> bool,
         [] fn maybe_unused_extern_crates: maybe_unused_extern_crates_node(CrateNum)
             -> Lrc<Vec<(DefId, Span)>>,
+        [] fn names_imported_by_glob_use: NamesImportedByGlobUse(DefId)
+            -> Lrc<FxHashSet<ast::Name>>,
 
         [] fn stability_index: stability_index_node(CrateNum) -> Lrc<stability::Index<'tcx>>,
         [] fn all_crate_nums: all_crate_nums_node(CrateNum) -> Lrc<Vec<CrateNum>>,
@@ -562,6 +594,7 @@ define_queries! { <'tcx>
             -> (Arc<DefIdSet>, Arc<Vec<Arc<CodegenUnit<'tcx>>>>),
         [] fn is_codegened_item: IsCodegenedItem(DefId) -> bool,
         [] fn codegen_unit: CodegenUnit(InternedString) -> Arc<CodegenUnit<'tcx>>,
+        [] fn backend_optimization_level: BackendOptimizationLevel(CrateNum) -> OptLevel,
     },
 
     Other {
@@ -716,32 +749,6 @@ define_queries! { <'tcx>
     },
 }
 
-// `try_get_query` can't be public because it uses the private query
-// implementation traits, so we provide access to it selectively.
-impl<'a, 'tcx, 'lcx> TyCtxt<'a, 'tcx, 'lcx> {
-    pub fn try_adt_sized_constraint(
-        self,
-        span: Span,
-        key: DefId,
-    ) -> Result<&'tcx [Ty<'tcx>], Box<DiagnosticBuilder<'a>>> {
-        self.try_get_query::<queries::adt_sized_constraint<'_>>(span, key)
-    }
-    pub fn try_needs_drop_raw(
-        self,
-        span: Span,
-        key: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
-    ) -> Result<bool, Box<DiagnosticBuilder<'a>>> {
-        self.try_get_query::<queries::needs_drop_raw<'_>>(span, key)
-    }
-    pub fn try_optimized_mir(
-        self,
-        span: Span,
-        key: DefId,
-    ) -> Result<&'tcx mir::Mir<'tcx>, Box<DiagnosticBuilder<'a>>> {
-        self.try_get_query::<queries::optimized_mir<'_>>(span, key)
-    }
-}
-
 //////////////////////////////////////////////////////////////////////
 // These functions are little shims used to find the dep-node for a
 // given query when there is not a *direct* mapping:
diff --git a/src/librustc/ty/query/on_disk_cache.rs b/src/librustc/ty/query/on_disk_cache.rs
index a674e942b3893..c16f861dedb50 100644
--- a/src/librustc/ty/query/on_disk_cache.rs
+++ b/src/librustc/ty/query/on_disk_cache.rs
@@ -1,28 +1,29 @@
-use dep_graph::{DepNodeIndex, SerializedDepNodeIndex};
+use crate::dep_graph::{DepNodeIndex, SerializedDepNodeIndex};
+use crate::hir;
+use crate::hir::def_id::{CrateNum, DefIndex, DefId, LocalDefId, LOCAL_CRATE};
+use crate::hir::map::definitions::DefPathHash;
+use crate::ich::{CachingSourceMapView, Fingerprint};
+use crate::mir::{self, interpret};
+use crate::mir::interpret::{AllocDecodingSession, AllocDecodingState};
+use crate::rustc_serialize::{Decodable, Decoder, Encodable, Encoder, opaque,
+                      SpecializedDecoder, SpecializedEncoder,
+                      UseSpecializedDecodable, UseSpecializedEncodable};
+use crate::session::{CrateDisambiguator, Session};
+use crate::ty;
+use crate::ty::codec::{self as ty_codec, TyDecoder, TyEncoder};
+use crate::ty::context::TyCtxt;
+use crate::util::common::time;
+
 use errors::Diagnostic;
-use hir;
-use hir::def_id::{CrateNum, DefIndex, DefId, LocalDefId, LOCAL_CRATE};
-use hir::map::definitions::DefPathHash;
-use ich::{CachingSourceMapView, Fingerprint};
-use mir::{self, interpret};
-use mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_data_structures::sync::{Lrc, Lock, HashMapExt, Once};
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
-use rustc_serialize::{Decodable, Decoder, Encodable, Encoder, opaque,
-                      SpecializedDecoder, SpecializedEncoder,
-                      UseSpecializedDecodable, UseSpecializedEncodable};
-use session::{CrateDisambiguator, Session};
 use std::mem;
 use syntax::ast::NodeId;
 use syntax::source_map::{SourceMap, StableSourceFileId};
 use syntax_pos::{BytePos, Span, DUMMY_SP, SourceFile};
 use syntax_pos::hygiene::{Mark, SyntaxContext, ExpnInfo};
-use ty;
-use ty::codec::{self as ty_codec, TyDecoder, TyEncoder};
-use ty::context::TyCtxt;
-use util::common::time;
 
 const TAG_FILE_FOOTER: u128 = 0xC0FFEE_C0FFEE_C0FFEE_C0FFEE_C0FFEE;
 
@@ -103,7 +104,7 @@ impl AbsoluteBytePos {
 }
 
 impl<'sess> OnDiskCache<'sess> {
-    /// Create a new OnDiskCache instance from the serialized data in `data`.
+    /// Creates a new OnDiskCache instance from the serialized data in `data`.
     pub fn new(sess: &'sess Session, data: Vec<u8>, start_pos: usize) -> OnDiskCache<'sess> {
         debug_assert!(sess.opts.incremental.is_some());
 
@@ -202,7 +203,7 @@ impl<'sess> OnDiskCache<'sess> {
             let mut query_result_index = EncodedQueryResultIndex::new();
 
             time(tcx.sess, "encode query results", || {
-                use ty::query::queries::*;
+                use crate::ty::query::queries::*;
                 let enc = &mut encoder;
                 let qri = &mut query_result_index;
 
@@ -225,12 +226,12 @@ impl<'sess> OnDiskCache<'sess> {
                 encode_query_results::<specialization_graph_of<'_>, _>(tcx, enc, qri)?;
 
                 // const eval is special, it only encodes successfully evaluated constants
-                use ty::query::QueryAccessors;
+                use crate::ty::query::QueryAccessors;
                 let cache = const_eval::query_cache(tcx).borrow();
                 assert!(cache.active.is_empty());
                 for (key, entry) in cache.results.iter() {
-                    use ty::query::config::QueryDescription;
-                    if const_eval::cache_on_disk(key.clone()) {
+                    use crate::ty::query::config::QueryDescription;
+                    if const_eval::cache_on_disk(tcx, key.clone()) {
                         if let Ok(ref value) = entry.value {
                             let dep_node = SerializedDepNodeIndex::new(entry.index.index());
 
@@ -325,7 +326,7 @@ impl<'sess> OnDiskCache<'sess> {
         })
     }
 
-    /// Load a diagnostic emitted during the previous compilation session.
+    /// Loads a diagnostic emitted during the previous compilation session.
     pub fn load_diagnostics<'a, 'tcx>(&self,
                                       tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                       dep_node_index: SerializedDepNodeIndex)
@@ -339,7 +340,7 @@ impl<'sess> OnDiskCache<'sess> {
         diagnostics.unwrap_or_default()
     }
 
-    /// Store a diagnostic emitted during the current compilation session.
+    /// Stores a diagnostic emitted during the current compilation session.
     /// Anything stored like this will be available via `load_diagnostics` in
     /// the next compilation session.
     #[inline(never)]
@@ -353,7 +354,7 @@ impl<'sess> OnDiskCache<'sess> {
     }
 
     /// Returns the cached query result if there is something in the cache for
-    /// the given SerializedDepNodeIndex. Otherwise returns None.
+    /// the given `SerializedDepNodeIndex`; otherwise returns `None`.
     pub fn try_load_query_result<'tcx, T>(&self,
                                           tcx: TyCtxt<'_, 'tcx, 'tcx>,
                                           dep_node_index: SerializedDepNodeIndex)
@@ -366,7 +367,7 @@ impl<'sess> OnDiskCache<'sess> {
                           "query result")
     }
 
-    /// Store a diagnostic emitted during computation of an anonymous query.
+    /// Stores a diagnostic emitted during computation of an anonymous query.
     /// Since many anonymous queries can share the same `DepNode`, we aggregate
     /// them -- as opposed to regular queries where we assume that there is a
     /// 1:1 relationship between query-key and `DepNode`.
@@ -777,7 +778,7 @@ impl<'enc, 'a, 'tcx, E> CacheEncoder<'enc, 'a, 'tcx, E>
                                                  value: &V)
                                                  -> Result<(), E::Error>
     {
-        use ty::codec::TyEncoder;
+        use crate::ty::codec::TyEncoder;
         let start_pos = self.position();
 
         tag.encode(self)?;
@@ -1086,7 +1087,7 @@ fn encode_query_results<'enc, 'a, 'tcx, Q, E>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let map = Q::query_cache(tcx).borrow();
     assert!(map.active.is_empty());
     for (key, entry) in map.results.iter() {
-        if Q::cache_on_disk(key.clone()) {
+        if Q::cache_on_disk(tcx, key.clone()) {
             let dep_node = SerializedDepNodeIndex::new(entry.index.index());
 
             // Record position of the cache entry
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index 562cd75a75ff4..37cb6753ed5b2 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -1,24 +1,26 @@
-//! The implementation of the query system itself. Defines the macros
-//! that generate the actual methods on tcx which find and execute the
-//! provider, manage the caches, and so forth.
+//! The implementation of the query system itself. This defines the macros that
+//! generate the actual methods on tcx which find and execute the provider,
+//! manage the caches, and so forth.
+
+use crate::dep_graph::{DepNodeIndex, DepNode, DepKind, SerializedDepNodeIndex};
+use crate::ty::tls;
+use crate::ty::{TyCtxt};
+use crate::ty::query::Query;
+use crate::ty::query::config::{QueryConfig, QueryDescription};
+use crate::ty::query::job::{QueryJob, QueryResult, QueryInfo};
+use crate::ty::item_path;
+
+use crate::util::common::{profq_msg, ProfileQueriesMsg, QueryMsg};
 
-use dep_graph::{DepNodeIndex, DepNode, DepKind, DepNodeColor};
 use errors::DiagnosticBuilder;
 use errors::Level;
 use errors::Diagnostic;
 use errors::FatalError;
-use ty::tls;
-use ty::{TyCtxt};
-use ty::query::Query;
-use ty::query::config::{QueryConfig, QueryDescription};
-use ty::query::job::{QueryJob, QueryResult, QueryInfo};
-use ty::item_path;
-
-use util::common::{profq_msg, ProfileQueriesMsg, QueryMsg};
-
 use rustc_data_structures::fx::{FxHashMap};
 use rustc_data_structures::sync::{Lrc, Lock};
 use rustc_data_structures::thin_vec::ThinVec;
+#[cfg(not(parallel_compiler))]
+use rustc_data_structures::cold_path;
 use std::mem;
 use std::ptr;
 use std::collections::hash_map::Entry;
@@ -113,8 +115,8 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
             let mut lock = cache.borrow_mut();
             if let Some(value) = lock.results.get(key) {
                 profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
-                tcx.sess.profiler(|p| p.record_query_hit(Q::CATEGORY));
-                let result = Ok((value.value.clone(), value.index));
+                tcx.sess.profiler(|p| p.record_query_hit(Q::NAME, Q::CATEGORY));
+                let result = (value.value.clone(), value.index);
                 #[cfg(debug_assertions)]
                 {
                     lock.cache_hits += 1;
@@ -124,7 +126,15 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
             let job = match lock.active.entry((*key).clone()) {
                 Entry::Occupied(entry) => {
                     match *entry.get() {
-                        QueryResult::Started(ref job) => job.clone(),
+                        QueryResult::Started(ref job) => {
+                            //For parallel queries, we'll block and wait until the query running
+                            //in another thread has completed. Record how long we wait in the
+                            //self-profiler
+                            #[cfg(parallel_compiler)]
+                            tcx.sess.profiler(|p| p.query_blocked_start(Q::NAME, Q::CATEGORY));
+
+                            job.clone()
+                        },
                         QueryResult::Poisoned => FatalError.raise(),
                     }
                 }
@@ -152,16 +162,21 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
             mem::drop(lock);
 
             // If we are single-threaded we know that we have cycle error,
-            // so we just turn the errror
-            #[cfg(not(parallel_queries))]
-            return job.cycle_error(tcx, span);
+            // so we just return the error
+            #[cfg(not(parallel_compiler))]
+            return TryGetJob::Cycle(cold_path(|| {
+                Q::handle_cycle_error(tcx, job.find_cycle_in_stack(tcx, span))
+            }));
 
             // With parallel queries we might just have to wait on some other
             // thread
-            #[cfg(parallel_queries)]
+            #[cfg(parallel_compiler)]
             {
-                if let Err(cycle) = job.await(tcx, span) {
-                    return TryGetJob::JobCompleted(Err(cycle));
+                let result = job.r#await(tcx, span);
+                tcx.sess.profiler(|p| p.query_blocked_end(Q::NAME, Q::CATEGORY));
+
+                if let Err(cycle) = result {
+                    return TryGetJob::Cycle(Q::handle_cycle_error(tcx, cycle));
                 }
             }
         }
@@ -188,40 +203,6 @@ impl<'a, 'tcx, Q: QueryDescription<'tcx>> JobOwner<'a, 'tcx, Q> {
 
         job.signal_complete();
     }
-
-    /// Executes a job by changing the ImplicitCtxt to point to the
-    /// new query job while it executes. It returns the diagnostics
-    /// captured during execution and the actual result.
-    #[inline(always)]
-    pub(super) fn start<'lcx, F, R>(
-        &self,
-        tcx: TyCtxt<'_, 'tcx, 'lcx>,
-        diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
-        compute: F)
-    -> R
-    where
-        F: for<'b> FnOnce(TyCtxt<'b, 'tcx, 'lcx>) -> R
-    {
-        // The TyCtxt stored in TLS has the same global interner lifetime
-        // as `tcx`, so we use `with_related_context` to relate the 'gcx lifetimes
-        // when accessing the ImplicitCtxt
-        tls::with_related_context(tcx, move |current_icx| {
-            // Update the ImplicitCtxt to point to our new query job
-            let new_icx = tls::ImplicitCtxt {
-                tcx: tcx.global_tcx(),
-                query: Some(self.job.clone()),
-                diagnostics,
-                layout_depth: current_icx.layout_depth,
-                task_deps: current_icx.task_deps,
-            };
-
-            // Use the ImplicitCtxt while we execute the query
-            tls::enter_context(&new_icx, |_| {
-                compute(tcx)
-            })
-        })
-    }
-
 }
 
 #[inline(always)]
@@ -261,16 +242,52 @@ pub(super) enum TryGetJob<'a, 'tcx: 'a, D: QueryDescription<'tcx> + 'a> {
     /// The query was already completed.
     /// Returns the result of the query and its dep node index
     /// if it succeeded or a cycle error if it failed
-    JobCompleted(Result<(D::Value, DepNodeIndex), Box<CycleError<'tcx>>>),
+    JobCompleted((D::Value, DepNodeIndex)),
+
+    /// Trying to execute the query resulted in a cycle.
+    Cycle(D::Value),
 }
 
 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
+    /// Executes a job by changing the ImplicitCtxt to point to the
+    /// new query job while it executes. It returns the diagnostics
+    /// captured during execution and the actual result.
+    #[inline(always)]
+    pub(super) fn start_query<F, R>(
+        self,
+        job: Lrc<QueryJob<'gcx>>,
+        diagnostics: Option<&Lock<ThinVec<Diagnostic>>>,
+        compute: F)
+    -> R
+    where
+        F: for<'b, 'lcx> FnOnce(TyCtxt<'b, 'gcx, 'lcx>) -> R
+    {
+        // The TyCtxt stored in TLS has the same global interner lifetime
+        // as `self`, so we use `with_related_context` to relate the 'gcx lifetimes
+        // when accessing the ImplicitCtxt
+        tls::with_related_context(self, move |current_icx| {
+            // Update the ImplicitCtxt to point to our new query job
+            let new_icx = tls::ImplicitCtxt {
+                tcx: self.global_tcx(),
+                query: Some(job),
+                diagnostics,
+                layout_depth: current_icx.layout_depth,
+                task_deps: current_icx.task_deps,
+            };
+
+            // Use the ImplicitCtxt while we execute the query
+            tls::enter_context(&new_icx, |_| {
+                compute(self.global_tcx())
+            })
+        })
+    }
+
     #[inline(never)]
     #[cold]
     pub(super) fn report_cycle(
         self,
-        box CycleError { usage, cycle: stack }: Box<CycleError<'gcx>>
-    ) -> Box<DiagnosticBuilder<'a>>
+        CycleError { usage, cycle: stack }: CycleError<'gcx>
+    ) -> DiagnosticBuilder<'a>
     {
         assert!(!stack.is_empty());
 
@@ -304,7 +321,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                               &format!("cycle used when {}", query.describe(self)));
             }
 
-            return Box::new(err)
+            err
         })
     }
 
@@ -335,48 +352,13 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         eprintln!("end of query stack");
     }
 
-    /// Try to read a node index for the node dep_node.
-    /// A node will have an index, when it's already been marked green, or when we can mark it
-    /// green. This function will mark the current task as a reader of the specified node, when
-    /// a node index can be found for that node.
-    pub(super) fn try_mark_green_and_read(self, dep_node: &DepNode) -> Option<DepNodeIndex> {
-        match self.dep_graph.node_color(dep_node) {
-            Some(DepNodeColor::Green(dep_node_index)) => {
-                self.dep_graph.read_index(dep_node_index);
-                Some(dep_node_index)
-            }
-            Some(DepNodeColor::Red) => {
-                None
-            }
-            None => {
-                // try_mark_green (called below) will panic when full incremental
-                // compilation is disabled. If that's the case, we can't try to mark nodes
-                // as green anyway, so we can safely return None here.
-                if !self.dep_graph.is_fully_enabled() {
-                    return None;
-                }
-                match self.dep_graph.try_mark_green(self.global_tcx(), &dep_node) {
-                    Some(dep_node_index) => {
-                        debug_assert!(self.dep_graph.is_green(&dep_node));
-                        self.dep_graph.read_index(dep_node_index);
-                        Some(dep_node_index)
-                    }
-                    None => {
-                        None
-                    }
-                }
-            }
-        }
-    }
-
     #[inline(never)]
-    fn try_get_with<Q: QueryDescription<'gcx>>(
+    pub(super) fn get_query<Q: QueryDescription<'gcx>>(
         self,
         span: Span,
         key: Q::Key)
-    -> Result<Q::Value, Box<CycleError<'gcx>>>
-    {
-        debug!("ty::queries::{}::try_get_with(key={:?}, span={:?})",
+    -> Q::Value {
+        debug!("ty::query::get_query<{}>(key={:?}, span={:?})",
                Q::NAME,
                key,
                span);
@@ -390,36 +372,35 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         let job = match JobOwner::try_get(self, span, &key) {
             TryGetJob::NotYetStarted(job) => job,
-            TryGetJob::JobCompleted(result) => {
-                return result.map(|(v, index)| {
-                    self.dep_graph.read_index(index);
-                    v
-                })
+            TryGetJob::Cycle(result) => return result,
+            TryGetJob::JobCompleted((v, index)) => {
+                self.dep_graph.read_index(index);
+                return v
             }
         };
 
         // Fast path for when incr. comp. is off. `to_dep_node` is
         // expensive for some DepKinds.
         if !self.dep_graph.is_fully_enabled() {
-            let null_dep_node = DepNode::new_no_params(::dep_graph::DepKind::Null);
-            return Ok(self.force_query_with_job::<Q>(key, job, null_dep_node).0);
+            let null_dep_node = DepNode::new_no_params(crate::dep_graph::DepKind::Null);
+            return self.force_query_with_job::<Q>(key, job, null_dep_node).0;
         }
 
         let dep_node = Q::to_dep_node(self, &key);
 
         if dep_node.kind.is_anon() {
             profq_msg!(self, ProfileQueriesMsg::ProviderBegin);
-            self.sess.profiler(|p| p.start_activity(Q::CATEGORY));
+            self.sess.profiler(|p| p.start_query(Q::NAME, Q::CATEGORY));
 
             let ((result, dep_node_index), diagnostics) = with_diagnostics(|diagnostics| {
-                job.start(self, diagnostics, |tcx| {
+                self.start_query(job.job.clone(), diagnostics, |tcx| {
                     tcx.dep_graph.with_anon_task(dep_node.kind, || {
                         Q::compute(tcx.global_tcx(), key)
                     })
                 })
             });
 
-            self.sess.profiler(|p| p.end_activity(Q::CATEGORY));
+            self.sess.profiler(|p| p.end_query(Q::NAME, Q::CATEGORY));
             profq_msg!(self, ProfileQueriesMsg::ProviderEnd);
 
             self.dep_graph.read_index(dep_node_index);
@@ -431,29 +412,39 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
             job.complete(&result, dep_node_index);
 
-            return Ok(result);
+            return result;
         }
 
         if !dep_node.kind.is_input() {
-            if let Some(dep_node_index) = self.try_mark_green_and_read(&dep_node) {
-                return Ok(self.load_from_disk_and_cache_in_memory::<Q>(
-                    key,
-                    job,
-                    dep_node_index,
-                    &dep_node
-                ))
+            // The diagnostics for this query will be
+            // promoted to the current session during
+            // try_mark_green(), so we can ignore them here.
+            let loaded = self.start_query(job.job.clone(), None, |tcx| {
+                let marked = tcx.dep_graph.try_mark_green_and_read(tcx, &dep_node);
+                marked.map(|(prev_dep_node_index, dep_node_index)| {
+                    (tcx.load_from_disk_and_cache_in_memory::<Q>(
+                        key.clone(),
+                        prev_dep_node_index,
+                        dep_node_index,
+                        &dep_node
+                    ), dep_node_index)
+                })
+            });
+            if let Some((result, dep_node_index)) = loaded {
+                job.complete(&result, dep_node_index);
+                return result;
             }
         }
 
         let (result, dep_node_index) = self.force_query_with_job::<Q>(key, job, dep_node);
         self.dep_graph.read_index(dep_node_index);
-        Ok(result)
+        result
     }
 
     fn load_from_disk_and_cache_in_memory<Q: QueryDescription<'gcx>>(
         self,
         key: Q::Key,
-        job: JobOwner<'a, 'gcx, Q>,
+        prev_dep_node_index: SerializedDepNodeIndex,
         dep_node_index: DepNodeIndex,
         dep_node: &DepNode
     ) -> Q::Value
@@ -464,12 +455,11 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         debug_assert!(self.dep_graph.is_green(dep_node));
 
         // First we try to load the result from the on-disk cache
-        let result = if Q::cache_on_disk(key.clone()) &&
+        let result = if Q::cache_on_disk(self.global_tcx(), key.clone()) &&
                         self.sess.opts.debugging_opts.incremental_queries {
-            let prev_dep_node_index =
-                self.dep_graph.prev_dep_node_index_of(dep_node);
-            let result = Q::try_load_from_disk(self.global_tcx(),
-                                               prev_dep_node_index);
+            self.sess.profiler(|p| p.incremental_load_result_start(Q::NAME));
+            let result = Q::try_load_from_disk(self.global_tcx(), prev_dep_node_index);
+            self.sess.profiler(|p| p.incremental_load_result_end(Q::NAME));
 
             // We always expect to find a cached result for things that
             // can be forced from DepNode.
@@ -485,27 +475,22 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         let result = if let Some(result) = result {
             profq_msg!(self, ProfileQueriesMsg::CacheHit);
-            self.sess.profiler(|p| p.record_query_hit(Q::CATEGORY));
+            self.sess.profiler(|p| p.record_query_hit(Q::NAME, Q::CATEGORY));
 
             result
         } else {
             // We could not load a result from the on-disk cache, so
             // recompute.
 
-            self.sess.profiler(|p| p.start_activity(Q::CATEGORY));
+            self.sess.profiler(|p| p.start_query(Q::NAME, Q::CATEGORY));
 
-            // The diagnostics for this query have already been
-            // promoted to the current session during
-            // try_mark_green(), so we can ignore them here.
-            let result = job.start(self, None, |tcx| {
-                // The dep-graph for this computation is already in
-                // place
-                tcx.dep_graph.with_ignore(|| {
-                    Q::compute(tcx, key)
-                })
+            // The dep-graph for this computation is already in
+            // place
+            let result = self.dep_graph.with_ignore(|| {
+                Q::compute(self, key)
             });
 
-            self.sess.profiler(|p| p.end_activity(Q::CATEGORY));
+            self.sess.profiler(|p| p.end_query(Q::NAME, Q::CATEGORY));
             result
         };
 
@@ -519,8 +504,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             self.dep_graph.mark_loaded_from_cache(dep_node_index, true);
         }
 
-        job.complete(&result, dep_node_index);
-
         result
     }
 
@@ -532,8 +515,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         dep_node: &DepNode,
         dep_node_index: DepNodeIndex,
     ) {
-        use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
-        use ich::Fingerprint;
+        use crate::ich::Fingerprint;
 
         assert!(Some(self.dep_graph.fingerprint_of(dep_node_index)) ==
                 self.dep_graph.prev_fingerprint_of(dep_node),
@@ -542,11 +524,8 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
         debug!("BEGIN verify_ich({:?})", dep_node);
         let mut hcx = self.create_stable_hashing_context();
-        let mut hasher = StableHasher::new();
-
-        result.hash_stable(&mut hcx, &mut hasher);
 
-        let new_hash: Fingerprint = hasher.finish();
+        let new_hash = Q::hash_result(&mut hcx, result).unwrap_or(Fingerprint::ZERO);
         debug!("END verify_ich({:?})", dep_node);
 
         let old_hash = self.dep_graph.fingerprint_of(dep_node_index);
@@ -574,32 +553,34 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 key, dep_node);
 
         profq_msg!(self, ProfileQueriesMsg::ProviderBegin);
-        self.sess.profiler(|p| p.start_activity(Q::CATEGORY));
+        self.sess.profiler(|p| p.start_query(Q::NAME, Q::CATEGORY));
 
         let ((result, dep_node_index), diagnostics) = with_diagnostics(|diagnostics| {
-            job.start(self, diagnostics, |tcx| {
+            self.start_query(job.job.clone(), diagnostics, |tcx| {
                 if dep_node.kind.is_eval_always() {
                     tcx.dep_graph.with_eval_always_task(dep_node,
                                                         tcx,
                                                         key,
-                                                        Q::compute)
+                                                        Q::compute,
+                                                        Q::hash_result)
                 } else {
                     tcx.dep_graph.with_task(dep_node,
                                             tcx,
                                             key,
-                                            Q::compute)
+                                            Q::compute,
+                                            Q::hash_result)
                 }
             })
         });
 
-        self.sess.profiler(|p| p.end_activity(Q::CATEGORY));
+        self.sess.profiler(|p| p.end_query(Q::NAME, Q::CATEGORY));
         profq_msg!(self, ProfileQueriesMsg::ProviderEnd);
 
         if unlikely!(self.sess.opts.debugging_opts.query_dep_graph) {
             self.dep_graph.mark_loaded_from_cache(dep_node_index, false);
         }
 
-        if dep_node.kind != ::dep_graph::DepKind::Null {
+        if dep_node.kind != crate::dep_graph::DepKind::Null {
             if unlikely!(!diagnostics.is_empty()) {
                 self.queries.on_disk_cache
                     .store_diagnostics(dep_node_index, diagnostics);
@@ -624,7 +605,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // Ensuring an "input" or anonymous query makes no sense
         assert!(!dep_node.kind.is_anon());
         assert!(!dep_node.kind.is_input());
-        if self.try_mark_green_and_read(&dep_node).is_none() {
+        if self.dep_graph.try_mark_green_and_read(self, &dep_node).is_none() {
             // A None return from `try_mark_green_and_read` means that this is either
             // a new dep node or that the dep node has already been marked red.
             // Either way, we can't call `dep_graph.read()` as we don't have the
@@ -635,7 +616,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             let _ = self.get_query::<Q>(DUMMY_SP, key);
         } else {
             profq_msg!(self, ProfileQueriesMsg::CacheHit);
-            self.sess.profiler(|p| p.record_query_hit(Q::CATEGORY));
+            self.sess.profiler(|p| p.record_query_hit(Q::NAME, Q::CATEGORY));
         }
     }
 
@@ -655,63 +636,46 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         // Ensure that only one of them runs the query
         let job = match JobOwner::try_get(self, span, &key) {
             TryGetJob::NotYetStarted(job) => job,
-            TryGetJob::JobCompleted(result) => {
-                if let Err(e) = result {
-                    self.report_cycle(e).emit();
-                }
+            TryGetJob::Cycle(_) |
+            TryGetJob::JobCompleted(_) => {
                 return
             }
         };
         self.force_query_with_job::<Q>(key, job, dep_node);
     }
-
-    pub(super) fn try_get_query<Q: QueryDescription<'gcx>>(
-        self,
-        span: Span,
-        key: Q::Key,
-    ) -> Result<Q::Value, Box<DiagnosticBuilder<'a>>> {
-        match self.try_get_with::<Q>(span, key) {
-            Ok(e) => Ok(e),
-            Err(e) => Err(self.report_cycle(e)),
-        }
-    }
-
-    // FIXME: Try uninlining this
-    #[inline(always)]
-    pub(super) fn get_query<Q: QueryDescription<'gcx>>(
-        self,
-        span: Span,
-        key: Q::Key,
-    ) -> Q::Value {
-        self.try_get_with::<Q>(span, key).unwrap_or_else(|e| {
-            self.emit_error::<Q>(e)
-        })
-    }
-
-    #[inline(never)]
-    #[cold]
-    fn emit_error<Q: QueryDescription<'gcx>>(
-        self,
-        e: Box<CycleError<'gcx>>,
-    ) -> Q::Value {
-        self.report_cycle(e).emit();
-        Q::handle_cycle_error(self)
-    }
 }
 
 macro_rules! handle_cycle_error {
-    ([][$this: expr]) => {{
-        Value::from_cycle_error($this.global_tcx())
+    ([][$tcx: expr, $error:expr]) => {{
+        $tcx.report_cycle($error).emit();
+        Value::from_cycle_error($tcx.global_tcx())
+    }};
+    ([fatal_cycle$(, $modifiers:ident)*][$tcx:expr, $error:expr]) => {{
+        $tcx.report_cycle($error).emit();
+        $tcx.sess.abort_if_errors();
+        unreachable!()
     }};
-    ([fatal_cycle$(, $modifiers:ident)*][$this:expr]) => {{
-        $this.sess.abort_if_errors();
-        unreachable!();
+    ([cycle_delay_bug$(, $modifiers:ident)*][$tcx:expr, $error:expr]) => {{
+        $tcx.report_cycle($error).delay_as_bug();
+        Value::from_cycle_error($tcx.global_tcx())
     }};
     ([$other:ident$(, $modifiers:ident)*][$($args:tt)*]) => {
         handle_cycle_error!([$($modifiers),*][$($args)*])
     };
 }
 
+macro_rules! hash_result {
+    ([][$hcx:expr, $result:expr]) => {{
+        dep_graph::hash_result($hcx, &$result)
+    }};
+    ([no_hash$(, $modifiers:ident)*][$hcx:expr, $result:expr]) => {{
+        None
+    }};
+    ([$other:ident$(, $modifiers:ident)*][$($args:tt)*]) => {
+        hash_result!([$($modifiers),*][$($args)*])
+    };
+}
+
 macro_rules! define_queries {
     (<$tcx:tt> $($category:tt {
         $($(#[$attr:meta])* [$($modifiers:tt)*] fn $name:ident: $node:ident($K:ty) -> $V:ty,)*
@@ -728,16 +692,16 @@ macro_rules! define_queries_inner {
         [$($modifiers:tt)*] fn $name:ident: $node:ident($K:ty) -> $V:ty,)*) => {
 
         use std::mem;
-        #[cfg(parallel_queries)]
+        #[cfg(parallel_compiler)]
         use ty::query::job::QueryResult;
         use rustc_data_structures::sync::Lock;
-        use {
+        use crate::{
             rustc_data_structures::stable_hasher::HashStable,
             rustc_data_structures::stable_hasher::StableHasherResult,
             rustc_data_structures::stable_hasher::StableHasher,
             ich::StableHashingContext
         };
-        use util::profiling::ProfileCategory;
+        use crate::util::profiling::ProfileCategory;
 
         define_queries_struct! {
             tcx: $tcx,
@@ -762,6 +726,7 @@ macro_rules! define_queries_inner {
                 sess.profiler(|p| {
                     $(
                         p.record_computed_queries(
+                            <queries::$name<'_> as QueryConfig<'_>>::NAME,
                             <queries::$name<'_> as QueryConfig<'_>>::CATEGORY,
                             self.$name.lock().results.len()
                         );
@@ -769,7 +734,7 @@ macro_rules! define_queries_inner {
                 });
             }
 
-            #[cfg(parallel_queries)]
+            #[cfg(parallel_compiler)]
             pub fn collect_active_jobs(&self) -> Vec<Lrc<QueryJob<$tcx>>> {
                 let mut jobs = Vec::new();
 
@@ -980,7 +945,7 @@ macro_rules! define_queries_inner {
             #[allow(unused)]
             #[inline(always)]
             fn to_dep_node(tcx: TyCtxt<'_, $tcx, '_>, key: &Self::Key) -> DepNode {
-                use dep_graph::DepConstructor::*;
+                use crate::dep_graph::DepConstructor::*;
 
                 DepNode::new(tcx, $node(*key))
             }
@@ -999,24 +964,34 @@ macro_rules! define_queries_inner {
                 })
             }
 
-            fn handle_cycle_error(tcx: TyCtxt<'_, 'tcx, '_>) -> Self::Value {
-                handle_cycle_error!([$($modifiers)*][tcx])
+            fn hash_result(
+                _hcx: &mut StableHashingContext<'_>,
+                _result: &Self::Value
+            ) -> Option<Fingerprint> {
+                hash_result!([$($modifiers)*][_hcx, _result])
             }
-        }
 
-        impl<'a, $tcx, 'lcx> queries::$name<$tcx> {
-            /// Ensure that either this query has all green inputs or been executed.
-            /// Executing query::ensure(D) is considered a read of the dep-node D.
-            ///
-            /// This function is particularly useful when executing passes for their
-            /// side-effects -- e.g., in order to report errors for erroneous programs.
-            ///
-            /// Note: The optimization is only available during incr. comp.
-            pub fn ensure(tcx: TyCtxt<'a, $tcx, 'lcx>, key: $K) -> () {
-                tcx.ensure_query::<queries::$name<'_>>(key);
+            fn handle_cycle_error(
+                tcx: TyCtxt<'_, 'tcx, '_>,
+                error: CycleError<'tcx>
+            ) -> Self::Value {
+                handle_cycle_error!([$($modifiers)*][tcx, error])
             }
         })*
 
+        #[derive(Copy, Clone)]
+        pub struct TyCtxtEnsure<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
+            pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
+        }
+
+        impl<'a, $tcx, 'lcx> TyCtxtEnsure<'a, $tcx, 'lcx> {
+            $($(#[$attr])*
+            #[inline(always)]
+            pub fn $name(self, key: $K) {
+                self.tcx.ensure_query::<queries::$name<'_>>(key)
+            })*
+        }
+
         #[derive(Copy, Clone)]
         pub struct TyCtxtAt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
             pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
@@ -1032,7 +1007,16 @@ macro_rules! define_queries_inner {
         }
 
         impl<'a, $tcx, 'lcx> TyCtxt<'a, $tcx, 'lcx> {
-            /// Return a transparent wrapper for `TyCtxt` which uses
+            /// Returns a transparent wrapper for `TyCtxt`, which ensures queries
+            /// are executed instead of just returing their results.
+            #[inline(always)]
+            pub fn ensure(self) -> TyCtxtEnsure<'a, $tcx, 'lcx> {
+                TyCtxtEnsure {
+                    tcx: self,
+                }
+            }
+
+            /// Returns a transparent wrapper for `TyCtxt` which uses
             /// `span` as the location of queries performed through it.
             #[inline(always)]
             pub fn at(self, span: Span) -> TyCtxtAt<'a, $tcx, 'lcx> {
@@ -1073,7 +1057,7 @@ macro_rules! define_queries_struct {
     (tcx: $tcx:tt,
      input: ($(([$($modifiers:tt)*] [$($attr:tt)*] [$name:ident]))*)) => {
         pub struct Queries<$tcx> {
-            /// This provides access to the incr. comp. on-disk cache for query results.
+            /// This provides access to the incrimental comilation on-disk cache for query results.
             /// Do not access this directly. It is only meant to be used by
             /// `DepGraph::try_mark_green()` and the query infrastructure.
             pub(crate) on_disk_cache: OnDiskCache<'tcx>,
@@ -1129,29 +1113,29 @@ macro_rules! define_provider_struct {
 ///
 /// Now, if force_from_dep_node() would always fail, it would be pretty useless.
 /// Fortunately, we can use some contextual information that will allow us to
-/// reconstruct query-keys for certain kinds of DepNodes. In particular, we
-/// enforce by construction that the GUID/fingerprint of certain DepNodes is a
-/// valid DefPathHash. Since we also always build a huge table that maps every
-/// DefPathHash in the current codebase to the corresponding DefId, we have
+/// reconstruct query-keys for certain kinds of `DepNode`s. In particular, we
+/// enforce by construction that the GUID/fingerprint of certain `DepNode`s is a
+/// valid `DefPathHash`. Since we also always build a huge table that maps every
+/// `DefPathHash` in the current codebase to the corresponding `DefId`, we have
 /// everything we need to re-run the query.
 ///
 /// Take the `mir_validated` query as an example. Like many other queries, it
-/// just has a single parameter: the DefId of the item it will compute the
-/// validated MIR for. Now, when we call `force_from_dep_node()` on a dep-node
-/// with kind `MirValidated`, we know that the GUID/fingerprint of the dep-node
-/// is actually a DefPathHash, and can therefore just look up the corresponding
-/// DefId in `tcx.def_path_hash_to_def_id`.
+/// just has a single parameter: the `DefId` of the item it will compute the
+/// validated MIR for. Now, when we call `force_from_dep_node()` on a `DepNode`
+/// with kind `MirValidated`, we know that the GUID/fingerprint of the `DepNode`
+/// is actually a `DefPathHash`, and can therefore just look up the corresponding
+/// `DefId` in `tcx.def_path_hash_to_def_id`.
 ///
 /// When you implement a new query, it will likely have a corresponding new
-/// DepKind, and you'll have to support it here in `force_from_dep_node()`. As
-/// a rule of thumb, if your query takes a DefId or DefIndex as sole parameter,
+/// `DepKind`, and you'll have to support it here in `force_from_dep_node()`. As
+/// a rule of thumb, if your query takes a `DefId` or `DefIndex` as sole parameter,
 /// then `force_from_dep_node()` should not fail for it. Otherwise, you can just
 /// add it to the "We don't have enough information to reconstruct..." group in
 /// the match below.
 pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
                                            dep_node: &DepNode)
                                            -> bool {
-    use hir::def_id::LOCAL_CRATE;
+    use crate::hir::def_id::LOCAL_CRATE;
 
     // We must avoid ever having to call force_from_dep_node() for a
     // DepNode::CodegenUnit:
@@ -1191,7 +1175,7 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
     macro_rules! force {
         ($query:ident, $key:expr) => {
             {
-                tcx.force_query::<::ty::query::queries::$query<'_>>($key, DUMMY_SP, *dep_node);
+                tcx.force_query::<crate::ty::query::queries::$query<'_>>($key, DUMMY_SP, *dep_node);
             }
         }
     };
@@ -1281,6 +1265,10 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::CheckModLoops => { force!(check_mod_loops, def_id!()); }
         DepKind::CheckModUnstableApiUsage => { force!(check_mod_unstable_api_usage, def_id!()); }
         DepKind::CheckModItemTypes => { force!(check_mod_item_types, def_id!()); }
+        DepKind::CheckModPrivacy => { force!(check_mod_privacy, def_id!()); }
+        DepKind::CheckModIntrinsics => { force!(check_mod_intrinsics, def_id!()); }
+        DepKind::CheckModLiveness => { force!(check_mod_liveness, def_id!()); }
+        DepKind::CheckModImplWf => { force!(check_mod_impl_wf, def_id!()); }
         DepKind::CollectModItemTypes => { force!(collect_mod_item_types, def_id!()); }
         DepKind::Reachability => { force!(reachable_set, LOCAL_CRATE); }
         DepKind::MirKeys => { force!(mir_keys, LOCAL_CRATE); }
@@ -1362,6 +1350,7 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::CheckImplItemWellFormed => { force!(check_impl_item_well_formed, def_id!()); }
         DepKind::ReachableNonGenerics => { force!(reachable_non_generics, krate!()); }
         DepKind::NativeLibraries => { force!(native_libraries, krate!()); }
+        DepKind::EntryFn => { force!(entry_fn, krate!()); }
         DepKind::PluginRegistrarFn => { force!(plugin_registrar_fn, krate!()); }
         DepKind::ProcMacroDeclsStatic => { force!(proc_macro_decls_static, krate!()); }
         DepKind::CrateDisambiguator => { force!(crate_disambiguator, krate!()); }
@@ -1413,6 +1402,7 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::MaybeUnusedTraitImport => {
             force!(maybe_unused_trait_import, def_id!());
         }
+        DepKind::NamesImportedByGlobUse => { force!(names_imported_by_glob_use, def_id!()); }
         DepKind::MaybeUnusedExternCrates => { force!(maybe_unused_extern_crates, LOCAL_CRATE); }
         DepKind::StabilityIndex => { force!(stability_index, LOCAL_CRATE); }
         DepKind::AllTraits => { force!(all_traits, LOCAL_CRATE); }
@@ -1438,6 +1428,9 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::UpstreamMonomorphizationsFor => {
             force!(upstream_monomorphizations_for, def_id!());
         }
+        DepKind::BackendOptimizationLevel => {
+            force!(backend_optimization_level, krate!());
+        }
     }
 
     true
@@ -1452,13 +1445,13 @@ macro_rules! impl_load_from_cache {
             // Check whether the query invocation corresponding to the given
             // DepNode is eligible for on-disk-caching.
             pub fn cache_on_disk(&self, tcx: TyCtxt<'_, '_, '_>) -> bool {
-                use ty::query::queries;
-                use ty::query::QueryDescription;
+                use crate::ty::query::queries;
+                use crate::ty::query::QueryDescription;
 
                 match self.kind {
                     $(DepKind::$dep_kind => {
                         let def_id = self.extract_def_id(tcx).unwrap();
-                        queries::$query_name::cache_on_disk(def_id)
+                        queries::$query_name::cache_on_disk(tcx.global_tcx(), def_id)
                     })*
                     _ => false
                 }
diff --git a/src/librustc/ty/query/values.rs b/src/librustc/ty/query/values.rs
index 3f84f1bc78972..a4b8d365a12ef 100644
--- a/src/librustc/ty/query/values.rs
+++ b/src/librustc/ty/query/values.rs
@@ -1,4 +1,5 @@
-use ty::{self, Ty, TyCtxt};
+use crate::ty::{self, Ty, TyCtxt, AdtSizedConstraint};
+use crate::ty::util::NeedsDrop;
 
 use syntax::symbol::Symbol;
 
@@ -31,3 +32,14 @@ impl<'tcx> Value<'tcx> for ty::SymbolName {
     }
 }
 
+impl<'tcx> Value<'tcx> for NeedsDrop {
+    fn from_cycle_error(_: TyCtxt<'_, 'tcx, 'tcx>) -> Self {
+        NeedsDrop(false)
+    }
+}
+
+impl<'tcx> Value<'tcx> for AdtSizedConstraint<'tcx> {
+    fn from_cycle_error(tcx: TyCtxt<'_, 'tcx, 'tcx>) -> Self {
+        AdtSizedConstraint(tcx.intern_type_list(&[tcx.types.err]))
+    }
+}
diff --git a/src/librustc/ty/relate.rs b/src/librustc/ty/relate.rs
index a16d6fea74c0b..db248072d9b50 100644
--- a/src/librustc/ty/relate.rs
+++ b/src/librustc/ty/relate.rs
@@ -4,18 +4,18 @@
 //! types or regions but can be other things. Examples of type relations are
 //! subtyping, type equality, etc.
 
-use hir::def_id::DefId;
-use ty::subst::{Kind, UnpackedKind, Substs};
-use ty::{self, Ty, TyCtxt, TypeFoldable};
-use ty::error::{ExpectedFound, TypeError};
-use mir::interpret::GlobalId;
-use util::common::ErrorReported;
+use crate::hir::def_id::DefId;
+use crate::ty::subst::{Kind, UnpackedKind, Substs};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
+use crate::ty::error::{ExpectedFound, TypeError};
+use crate::mir::interpret::GlobalId;
+use crate::util::common::ErrorReported;
 use syntax_pos::DUMMY_SP;
 use std::rc::Rc;
 use std::iter;
 use rustc_target::spec::abi;
-use hir as ast;
-use traits;
+use crate::hir as ast;
+use crate::traits;
 
 pub type RelateResult<'tcx, T> = Result<T, TypeError<'tcx>>;
 
@@ -30,7 +30,7 @@ pub trait TypeRelation<'a, 'gcx: 'a+'tcx, 'tcx: 'a> : Sized {
     /// Returns a static string we can use for printouts.
     fn tag(&self) -> &'static str;
 
-    /// Returns true if the value `a` is the "expected" type in the
+    /// Returns `true` if the value `a` is the "expected" type in the
     /// relation. Just affects error messages.
     fn a_is_expected(&self) -> bool;
 
@@ -588,7 +588,7 @@ impl<'tcx> Relate<'tcx> for &'tcx ty::List<ty::ExistentialPredicate<'tcx>> {
 
         let tcx = relation.tcx();
         let v = a.iter().zip(b.iter()).map(|(ep_a, ep_b)| {
-            use ty::ExistentialPredicate::*;
+            use crate::ty::ExistentialPredicate::*;
             match (*ep_a, *ep_b) {
                 (Trait(ref a), Trait(ref b)) => Ok(Trait(relation.relate(a, b)?)),
                 (Projection(ref a), Projection(ref b)) => Ok(Projection(relation.relate(a, b)?)),
@@ -746,7 +746,7 @@ impl<'tcx> Relate<'tcx> for traits::WhereClause<'tcx> {
     ) -> RelateResult<'tcx, traits::WhereClause<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::WhereClause::*;
+        use crate::traits::WhereClause::*;
         match (a, b) {
             (Implemented(a_pred), Implemented(b_pred)) => {
                 Ok(Implemented(relation.relate(a_pred, b_pred)?))
@@ -783,7 +783,7 @@ impl<'tcx> Relate<'tcx> for traits::WellFormed<'tcx> {
     ) -> RelateResult<'tcx, traits::WellFormed<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::WellFormed::*;
+        use crate::traits::WellFormed::*;
         match (a, b) {
             (Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
             (Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
@@ -800,7 +800,7 @@ impl<'tcx> Relate<'tcx> for traits::FromEnv<'tcx> {
     ) -> RelateResult<'tcx, traits::FromEnv<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::FromEnv::*;
+        use crate::traits::FromEnv::*;
         match (a, b) {
             (Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
             (Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
@@ -817,7 +817,7 @@ impl<'tcx> Relate<'tcx> for traits::DomainGoal<'tcx> {
     ) -> RelateResult<'tcx, traits::DomainGoal<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::DomainGoal::*;
+        use crate::traits::DomainGoal::*;
         match (a, b) {
             (Holds(a_wc), Holds(b_wc)) => Ok(Holds(relation.relate(a_wc, b_wc)?)),
             (WellFormed(a_wf), WellFormed(b_wf)) => Ok(WellFormed(relation.relate(a_wf, b_wf)?)),
@@ -840,7 +840,7 @@ impl<'tcx> Relate<'tcx> for traits::Goal<'tcx> {
     ) -> RelateResult<'tcx, traits::Goal<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::GoalKind::*;
+        use crate::traits::GoalKind::*;
         match (a, b) {
             (Implies(a_clauses, a_goal), Implies(b_clauses, b_goal)) => {
                 let clauses = relation.relate(a_clauses, b_clauses)?;
@@ -904,7 +904,7 @@ impl<'tcx> Relate<'tcx> for traits::Clause<'tcx> {
     ) -> RelateResult<'tcx, traits::Clause<'tcx>>
         where R: TypeRelation<'a, 'gcx, 'tcx>, 'gcx: 'tcx, 'tcx: 'a
     {
-        use traits::Clause::*;
+        use crate::traits::Clause::*;
         match (a, b) {
             (Implies(a_clause), Implies(b_clause)) => {
                 let clause = relation.relate(a_clause, b_clause)?;
diff --git a/src/librustc/ty/steal.rs b/src/librustc/ty/steal.rs
index 336a4c3bf2279..a8f9301ba51c9 100644
--- a/src/librustc/ty/steal.rs
+++ b/src/librustc/ty/steal.rs
@@ -12,14 +12,14 @@ use rustc_data_structures::sync::{RwLock, ReadGuard, MappedReadGuard};
 /// Steal<Mir<'tcx>>` (to be very specific). Now we can read from this
 /// as much as we want (using `borrow()`), but you can also
 /// `steal()`. Once you steal, any further attempt to read will panic.
-/// Therefore we know that -- assuming no ICE -- nobody is observing
+/// Therefore, we know that -- assuming no ICE -- nobody is observing
 /// the fact that the MIR was updated.
 ///
 /// Obviously, whenever you have a query that yields a `Steal` value,
 /// you must treat it with caution, and make sure that you know that
 /// -- once the value is stolen -- it will never be read from again.
-///
-/// FIXME(#41710) -- what is the best way to model linear queries?
+//
+// FIXME(#41710): what is the best way to model linear queries?
 pub struct Steal<T> {
     value: RwLock<Option<T>>
 }
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index 258470bf6f860..f9173836cc627 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -3,13 +3,13 @@
 //! hand, though we've recently added some macros (e.g.,
 //! `BraceStructLiftImpl!`) to help with the tedium.
 
-use mir::ProjectionKind;
-use mir::interpret::ConstValue;
-use ty::{self, Lift, Ty, TyCtxt};
-use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
+use crate::mir::ProjectionKind;
+use crate::mir::interpret::ConstValue;
+use crate::ty::{self, Lift, Ty, TyCtxt};
+use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 use smallvec::SmallVec;
-use mir::interpret;
+use crate::mir::interpret;
 
 use std::rc::Rc;
 
@@ -23,35 +23,35 @@ CloneTypeFoldableAndLiftImpls! {
     (),
     bool,
     usize,
-    ::ty::layout::VariantIdx,
+    crate::ty::layout::VariantIdx,
     u64,
     String,
-    ::middle::region::Scope,
+    crate::middle::region::Scope,
     ::syntax::ast::FloatTy,
     ::syntax::ast::NodeId,
     ::syntax_pos::symbol::Symbol,
-    ::hir::def::Def,
-    ::hir::def_id::DefId,
-    ::hir::InlineAsm,
-    ::hir::MatchSource,
-    ::hir::Mutability,
-    ::hir::Unsafety,
+    crate::hir::def::Def,
+    crate::hir::def_id::DefId,
+    crate::hir::InlineAsm,
+    crate::hir::MatchSource,
+    crate::hir::Mutability,
+    crate::hir::Unsafety,
     ::rustc_target::spec::abi::Abi,
-    ::mir::Local,
-    ::mir::Promoted,
-    ::traits::Reveal,
-    ::ty::adjustment::AutoBorrowMutability,
-    ::ty::AdtKind,
+    crate::mir::Local,
+    crate::mir::Promoted,
+    crate::traits::Reveal,
+    crate::ty::adjustment::AutoBorrowMutability,
+    crate::ty::AdtKind,
     // Including `BoundRegion` is a *bit* dubious, but direct
     // references to bound region appear in `ty::Error`, and aren't
     // really meant to be folded. In general, we can only fold a fully
     // general `Region`.
-    ::ty::BoundRegion,
-    ::ty::ClosureKind,
-    ::ty::IntVarValue,
-    ::ty::ParamTy,
-    ::ty::UniverseIndex,
-    ::ty::Variance,
+    crate::ty::BoundRegion,
+    crate::ty::ClosureKind,
+    crate::ty::IntVarValue,
+    crate::ty::ParamTy,
+    crate::ty::UniverseIndex,
+    crate::ty::Variance,
     ::syntax_pos::Span,
 }
 
@@ -421,7 +421,7 @@ impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
 impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
     type Lifted = ty::error::TypeError<'tcx>;
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-        use ty::error::TypeError::*;
+        use crate::ty::error::TypeError::*;
 
         Some(match *self {
             Mismatch => Mismatch,
@@ -434,6 +434,12 @@ impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
             RegionsDoesNotOutlive(a, b) => {
                 return tcx.lift(&(a, b)).map(|(a, b)| RegionsDoesNotOutlive(a, b))
             }
+            RegionsInsufficientlyPolymorphic(a, b) => {
+                return tcx.lift(&b).map(|b| RegionsInsufficientlyPolymorphic(a, b))
+            }
+            RegionsOverlyPolymorphic(a, b) => {
+                return tcx.lift(&b).map(|b| RegionsOverlyPolymorphic(a, b))
+            }
             RegionsPlaceholderMismatch => RegionsPlaceholderMismatch,
             IntMismatch(x) => IntMismatch(x),
             FloatMismatch(x) => FloatMismatch(x),
@@ -498,7 +504,7 @@ impl<'a, 'tcx> Lift<'tcx> for ConstValue<'a> {
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
         match *self {
             ConstValue::Scalar(x) => Some(ConstValue::Scalar(x)),
-            ConstValue::ScalarPair(x, y) => Some(ConstValue::ScalarPair(x, y)),
+            ConstValue::Slice(x, y) => Some(ConstValue::Slice(x, y)),
             ConstValue::ByRef(x, alloc, z) => Some(ConstValue::ByRef(
                 x, alloc.lift_to_tcx(tcx)?, z,
             )),
@@ -651,7 +657,7 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<ProjectionKind<'tcx>> {
 
 impl<'tcx> TypeFoldable<'tcx> for ty::instance::Instance<'tcx> {
     fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
-        use ty::InstanceDef::*;
+        use crate::ty::InstanceDef::*;
         Self {
             substs: self.substs.fold_with(folder),
             def: match self.def {
@@ -682,7 +688,7 @@ impl<'tcx> TypeFoldable<'tcx> for ty::instance::Instance<'tcx> {
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        use ty::InstanceDef::*;
+        use crate::ty::InstanceDef::*;
         self.substs.visit_with(visitor) ||
         match self.def {
             Item(did) | VtableShim(did) | Intrinsic(did) | Virtual(did, _) => {
@@ -1021,6 +1027,8 @@ EnumTypeFoldableImpl! {
         (ty::error::TypeError::FixedArraySize)(x),
         (ty::error::TypeError::ArgCount),
         (ty::error::TypeError::RegionsDoesNotOutlive)(a, b),
+        (ty::error::TypeError::RegionsInsufficientlyPolymorphic)(a, b),
+        (ty::error::TypeError::RegionsOverlyPolymorphic)(a, b),
         (ty::error::TypeError::RegionsPlaceholderMismatch),
         (ty::error::TypeError::IntMismatch)(x),
         (ty::error::TypeError::FloatMismatch)(x),
@@ -1042,7 +1050,7 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::LazyConst<'tcx> {
                 ty::LazyConst::Unevaluated(*def_id, substs.fold_with(folder))
             }
         };
-        folder.tcx().intern_lazy_const(new)
+        folder.tcx().mk_lazy_const(new)
     }
 
     fn fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index b98369b62ea37..350bc45026322 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -1,17 +1,17 @@
 //! This module contains `TyKind` and its major components.
 
-use hir;
-use hir::def_id::DefId;
-use infer::canonical::Canonical;
-use mir::interpret::ConstValue;
-use middle::region;
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::infer::canonical::Canonical;
+use crate::mir::interpret::ConstValue;
+use crate::middle::region;
 use polonius_engine::Atom;
 use rustc_data_structures::indexed_vec::Idx;
-use ty::subst::{Substs, Subst, Kind, UnpackedKind};
-use ty::{self, AdtDef, TypeFlags, Ty, TyCtxt, TypeFoldable};
-use ty::{List, TyS, ParamEnvAnd, ParamEnv};
-use util::captures::Captures;
-use mir::interpret::{Scalar, Pointer};
+use crate::ty::subst::{Substs, Subst, Kind, UnpackedKind};
+use crate::ty::{self, AdtDef, TypeFlags, Ty, TyCtxt, TypeFoldable};
+use crate::ty::{List, TyS, ParamEnvAnd, ParamEnv};
+use crate::util::captures::Captures;
+use crate::mir::interpret::{Scalar, Pointer};
 
 use smallvec::SmallVec;
 use std::iter;
@@ -47,7 +47,7 @@ pub enum BoundRegion {
 
     /// Named region parameters for functions (a in &'a T)
     ///
-    /// The def-id is needed to distinguish free regions in
+    /// The `DefId` is needed to distinguish free regions in
     /// the event of shadowing.
     BrNamed(DefId, InternedString),
 
@@ -87,7 +87,7 @@ pub enum TyKind<'tcx> {
     Bool,
 
     /// The primitive character type; holds a Unicode scalar value
-    /// (a non-surrogate code point).  Written as `char`.
+    /// (a non-surrogate code point). Written as `char`.
     Char,
 
     /// A primitive signed integer type. For example, `i32`.
@@ -107,6 +107,7 @@ pub enum TyKind<'tcx> {
     /// definition and not a concrete use of it.
     Adt(&'tcx AdtDef, &'tcx Substs<'tcx>),
 
+    /// An unsized FFI type that is opaque to Rust. Written as `extern type T`.
     Foreign(DefId),
 
     /// The pointee of a string slice. Written as `str`.
@@ -115,7 +116,7 @@ pub enum TyKind<'tcx> {
     /// An array with the given length. Written as `[T; n]`.
     Array(Ty<'tcx>, &'tcx ty::LazyConst<'tcx>),
 
-    /// The pointee of an array slice.  Written as `[T]`.
+    /// The pointee of an array slice. Written as `[T]`.
     Slice(Ty<'tcx>),
 
     /// A raw pointer. Written as `*mut T` or `*const T`
@@ -137,7 +138,7 @@ pub enum TyKind<'tcx> {
     /// ```
     FnDef(DefId, &'tcx Substs<'tcx>),
 
-    /// A pointer to a function.  Written as `fn() -> i32`.
+    /// A pointer to a function. Written as `fn() -> i32`.
     ///
     /// For example the type of `bar` here:
     ///
@@ -165,10 +166,10 @@ pub enum TyKind<'tcx> {
     /// The never type `!`
     Never,
 
-    /// A tuple type.  For example, `(i32, bool)`.
+    /// A tuple type. For example, `(i32, bool)`.
     Tuple(&'tcx List<Ty<'tcx>>),
 
-    /// The projection of an associated type.  For example,
+    /// The projection of an associated type. For example,
     /// `<T as Trait<..>>::N`.
     Projection(ProjectionTy<'tcx>),
 
@@ -277,7 +278,7 @@ static_assert!(MEM_SIZE_OF_TY_KIND: ::std::mem::size_of::<TyKind<'_>>() == 24);
 ///
 /// All right, you say, but why include the type parameters from the
 /// original function then? The answer is that codegen may need them
-/// when monomorphizing, and they may not appear in the upvars.  A
+/// when monomorphizing, and they may not appear in the upvars. A
 /// closure could capture no variables but still make use of some
 /// in-scope type parameter with a bound (e.g., if our example above
 /// had an extra `U: Default`, and the closure called `U::default()`).
@@ -294,9 +295,9 @@ static_assert!(MEM_SIZE_OF_TY_KIND: ::std::mem::size_of::<TyKind<'_>>() == 24);
 /// ## Generators
 ///
 /// Perhaps surprisingly, `ClosureSubsts` are also used for
-/// generators.  In that case, what is written above is only half-true
+/// generators. In that case, what is written above is only half-true
 /// -- the set of type parameters is similar, but the role of CK and
-/// CS are different.  CK represents the "yield type" and CS
+/// CS are different. CK represents the "yield type" and CS
 /// represents the "return type" of the generator.
 ///
 /// It'd be nice to split this struct into ClosureSubsts and
@@ -441,17 +442,17 @@ impl<'tcx> GeneratorSubsts<'tcx> {
         self.split(def_id, tcx).return_ty
     }
 
-    /// Return the "generator signature", which consists of its yield
+    /// Returns the "generator signature", which consists of its yield
     /// and return types.
     ///
-    /// NB. Some bits of the code prefers to see this wrapped in a
+    /// N.B., some bits of the code prefers to see this wrapped in a
     /// binder, but it never contains bound regions. Probably this
     /// function should be removed.
     pub fn poly_sig(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> PolyGenSig<'tcx> {
         ty::Binder::dummy(self.sig(def_id, tcx))
     }
 
-    /// Return the "generator signature", which consists of its yield
+    /// Returns the "generator signature", which consists of its yield
     /// and return types.
     pub fn sig(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> GenSig<'tcx> {
         ty::GenSig {
@@ -519,11 +520,11 @@ impl<'tcx> UpvarSubsts<'tcx> {
 
 #[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub enum ExistentialPredicate<'tcx> {
-    /// e.g., Iterator
+    /// E.g., `Iterator`.
     Trait(ExistentialTraitRef<'tcx>),
-    /// e.g., Iterator::Item = T
+    /// E.g., `Iterator::Item = T`.
     Projection(ExistentialProjection<'tcx>),
-    /// e.g., Send
+    /// E.g., `Send`.
     AutoTrait(DefId),
 }
 
@@ -550,7 +551,7 @@ impl<'a, 'gcx, 'tcx> ExistentialPredicate<'tcx> {
 impl<'a, 'gcx, 'tcx> Binder<ExistentialPredicate<'tcx>> {
     pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, self_ty: Ty<'tcx>)
         -> ty::Predicate<'tcx> {
-        use ty::ToPredicate;
+        use crate::ty::ToPredicate;
         match *self.skip_binder() {
             ExistentialPredicate::Trait(tr) => Binder(tr).with_self_ty(tcx, self_ty).to_predicate(),
             ExistentialPredicate::Projection(p) =>
@@ -654,12 +655,12 @@ impl<'tcx> Binder<&'tcx List<ExistentialPredicate<'tcx>>> {
 }
 
 /// A complete reference to a trait. These take numerous guises in syntax,
-/// but perhaps the most recognizable form is in a where clause:
+/// but perhaps the most recognizable form is in a where-clause:
 ///
 ///     T: Foo<U>
 ///
-/// This would be represented by a trait-reference where the def-id is the
-/// def-id for the trait `Foo` and the substs define `T` as parameter 0,
+/// This would be represented by a trait-reference where the `DefId` is the
+/// `DefId` for the trait `Foo` and the substs define `T` as parameter 0,
 /// and `U` as parameter 1.
 ///
 /// Trait references also appear in object types like `Foo<U>`, but in
@@ -765,9 +766,9 @@ impl<'a, 'gcx, 'tcx> ExistentialTraitRef<'tcx> {
         }
     }
 
-    /// Object types don't have a self-type specified. Therefore, when
+    /// Object types don't have a self type specified. Therefore, when
     /// we convert the principal trait-ref into a normal trait-ref,
-    /// you must give *some* self-type. A common choice is `mk_err()`
+    /// you must give *some* self type. A common choice is `mk_err()`
     /// or some placeholder type.
     pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, self_ty: Ty<'tcx>)
         -> ty::TraitRef<'tcx>  {
@@ -788,9 +789,9 @@ impl<'tcx> PolyExistentialTraitRef<'tcx> {
         self.skip_binder().def_id
     }
 
-    /// Object types don't have a self-type specified. Therefore, when
+    /// Object types don't have a self type specified. Therefore, when
     /// we convert the principal trait-ref into a normal trait-ref,
-    /// you must give *some* self-type. A common choice is `mk_err()`
+    /// you must give *some* self type. A common choice is `mk_err()`
     /// or some placeholder type.
     pub fn with_self_ty(&self, tcx: TyCtxt<'_, '_, 'tcx>,
                         self_ty: Ty<'tcx>)
@@ -828,7 +829,7 @@ impl<T> Binder<T> {
 
     /// Skips the binder and returns the "bound" value. This is a
     /// risky thing to do because it's easy to get confused about
-    /// debruijn indices and the like. It is usually better to
+    /// De Bruijn indices and the like. It is usually better to
     /// discharge the binder using `no_bound_vars` or
     /// `replace_late_bound_regions` or something like
     /// that. `skip_binder` is only valid when you are either
@@ -839,7 +840,7 @@ impl<T> Binder<T> {
     ///
     /// Some examples where `skip_binder` is reasonable:
     ///
-    /// - extracting the def-id from a PolyTraitRef;
+    /// - extracting the `DefId` from a PolyTraitRef;
     /// - comparing the self type of a PolyTraitRef to see if it is equal to
     ///   a type parameter `X`, since the type `X` does not reference any regions
     pub fn skip_binder(&self) -> &T {
@@ -883,8 +884,8 @@ impl<T> Binder<T> {
     }
 
     /// Given two things that have the same binder level,
-    /// and an operation that wraps on their contents, execute the operation
-    /// and then wrap its result.
+    /// and an operation that wraps on their contents, executes the operation
+    /// and then wraps its result.
     ///
     /// `f` should consider bound regions at depth 1 to be free, and
     /// anything it produces with bound regions at depth 1 will be
@@ -895,7 +896,7 @@ impl<T> Binder<T> {
         Binder(f(self.0, u.0))
     }
 
-    /// Split the contents into two things that share the same binder
+    /// Splits the contents into two things that share the same binder
     /// level as the original, returning two distinct binders.
     ///
     /// `f` should consider bound regions at depth 1 to be free, and
@@ -1117,14 +1118,14 @@ pub type Region<'tcx> = &'tcx RegionKind;
 /// ## Bound Regions
 ///
 /// These are regions that are stored behind a binder and must be substituted
-/// with some concrete region before being used. There are 2 kind of
-/// bound regions: early-bound, which are bound in an item's Generics,
-/// and are substituted by a Substs,  and late-bound, which are part of
-/// higher-ranked types (e.g., `for<'a> fn(&'a ())`) and are substituted by
+/// with some concrete region before being used. There are two kind of
+/// bound regions: early-bound, which are bound in an item's `Generics`,
+/// and are substituted by a `Substs`, and late-bound, which are part of
+/// higher-ranked types (e.g., `for<'a> fn(&'a ())`), and are substituted by
 /// the likes of `liberate_late_bound_regions`. The distinction exists
 /// because higher-ranked lifetimes aren't supported in all places. See [1][2].
 ///
-/// Unlike Param-s, bound regions are not supposed to exist "in the wild"
+/// Unlike `Param`s, bound regions are not supposed to exist "in the wild"
 /// outside their binder, e.g., in types passed to type inference, and
 /// should first be substituted (by placeholder regions, free regions,
 /// or region variables).
@@ -1140,7 +1141,7 @@ pub type Region<'tcx> = &'tcx RegionKind;
 /// To do this, we replace the bound regions with placeholder markers,
 /// which don't satisfy any relation not explicitly provided.
 ///
-/// There are 2 kinds of placeholder regions in rustc: `ReFree` and
+/// There are two kinds of placeholder regions in rustc: `ReFree` and
 /// `RePlaceholder`. When checking an item's body, `ReFree` is supposed
 /// to be used. These also support explicit bounds: both the internally-stored
 /// *scope*, which the region is assumed to outlive, as well as other
@@ -1166,13 +1167,13 @@ pub type Region<'tcx> = &'tcx RegionKind;
 /// [rustc guide]: https://rust-lang.github.io/rustc-guide/traits/hrtb.html
 #[derive(Clone, PartialEq, Eq, Hash, Copy, RustcEncodable, RustcDecodable, PartialOrd, Ord)]
 pub enum RegionKind {
-    // Region bound in a type or fn declaration which will be
-    // substituted 'early' -- that is, at the same time when type
-    // parameters are substituted.
+    /// Region bound in a type or fn declaration which will be
+    /// substituted 'early' -- that is, at the same time when type
+    /// parameters are substituted.
     ReEarlyBound(EarlyBoundRegion),
 
-    // Region bound in a function scope, which will be substituted when the
-    // function is called.
+    /// Region bound in a function scope, which will be substituted when the
+    /// function is called.
     ReLateBound(DebruijnIndex, BoundRegion),
 
     /// When checking a function body, the types of all arguments and so forth
@@ -1188,7 +1189,7 @@ pub enum RegionKind {
     /// Static data that has an "infinite" lifetime. Top in the region lattice.
     ReStatic,
 
-    /// A region variable.  Should not exist after typeck.
+    /// A region variable. Should not exist after typeck.
     ReVar(RegionVid),
 
     /// A placeholder region - basically the higher-ranked version of ReFree.
@@ -1345,11 +1346,11 @@ impl<'a, 'tcx, 'gcx> PolyExistentialProjection<'tcx> {
 
 impl DebruijnIndex {
     /// Returns the resulting index when this value is moved into
-    /// `amount` number of new binders. So e.g., if you had
+    /// `amount` number of new binders. So, e.g., if you had
     ///
     ///    for<'a> fn(&'a x)
     ///
-    /// and you wanted to change to
+    /// and you wanted to change it to
     ///
     ///    for<'a> fn(for<'b> fn(&'a x))
     ///
@@ -1377,7 +1378,7 @@ impl DebruijnIndex {
         *self = self.shifted_out(amount);
     }
 
-    /// Adjusts any Debruijn Indices so as to make `to_binder` the
+    /// Adjusts any De Bruijn indices so as to make `to_binder` the
     /// innermost binder. That is, if we have something bound at `to_binder`,
     /// it will now be bound at INNERMOST. This is an appropriate thing to do
     /// when moving a region out from inside binders:
@@ -1387,12 +1388,12 @@ impl DebruijnIndex {
     /// // Binder:  D3           D2        D1            ^^
     /// ```
     ///
-    /// Here, the region `'a` would have the debruijn index D3,
+    /// Here, the region `'a` would have the De Bruijn index D3,
     /// because it is the bound 3 binders out. However, if we wanted
     /// to refer to that region `'a` in the second argument (the `_`),
     /// those two binders would not be in scope. In that case, we
     /// might invoke `shift_out_to_binder(D3)`. This would adjust the
-    /// debruijn index of `'a` to D1 (the innermost binder).
+    /// De Bruijn index of `'a` to D1 (the innermost binder).
     ///
     /// If we invoke `shift_out_to_binder` and the region is in fact
     /// bound by one of the binders we are shifting out of, that is an
@@ -1443,7 +1444,7 @@ impl RegionKind {
         }
     }
 
-    /// Adjusts any Debruijn Indices so as to make `to_binder` the
+    /// Adjusts any De Bruijn indices so as to make `to_binder` the
     /// innermost binder. That is, if we have something bound at `to_binder`,
     /// it will now be bound at INNERMOST. This is an appropriate thing to do
     /// when moving a region out from inside binders:
@@ -1453,12 +1454,12 @@ impl RegionKind {
     /// // Binder:  D3           D2        D1            ^^
     /// ```
     ///
-    /// Here, the region `'a` would have the debruijn index D3,
+    /// Here, the region `'a` would have the De Bruijn index D3,
     /// because it is the bound 3 binders out. However, if we wanted
     /// to refer to that region `'a` in the second argument (the `_`),
     /// those two binders would not be in scope. In that case, we
     /// might invoke `shift_out_to_binder(D3)`. This would adjust the
-    /// debruijn index of `'a` to D1 (the innermost binder).
+    /// De Bruijn index of `'a` to D1 (the innermost binder).
     ///
     /// If we invoke `shift_out_to_binder` and the region is in fact
     /// bound by one of the binders we are shifting out of, that is an
@@ -1527,7 +1528,7 @@ impl RegionKind {
         flags
     }
 
-    /// Given an early-bound or free region, returns the def-id where it was bound.
+    /// Given an early-bound or free region, returns the `DefId` where it was bound.
     /// For example, consider the regions in this snippet of code:
     ///
     /// ```
@@ -1542,10 +1543,10 @@ impl RegionKind {
     /// }
     /// ```
     ///
-    /// Here, `free_region_binding_scope('a)` would return the def-id
+    /// Here, `free_region_binding_scope('a)` would return the `DefId`
     /// of the impl, and for all the other highlighted regions, it
-    /// would return the def-id of the function. In other cases (not shown), this
-    /// function might return the def-id of a closure.
+    /// would return the `DefId` of the function. In other cases (not shown), this
+    /// function might return the `DefId` of a closure.
     pub fn free_region_binding_scope(&self, tcx: TyCtxt<'_, '_, '_>) -> DefId {
         match self {
             ty::ReEarlyBound(br) => {
@@ -1771,7 +1772,7 @@ impl<'a, 'gcx, 'tcx> TyS<'tcx> {
         }
     }
 
-    /// Returns true if this type is a floating point type and false otherwise.
+    /// Returns `true` if this type is a floating point type.
     pub fn is_floating_point(&self) -> bool {
         match self.sty {
             Float(_) |
@@ -2063,6 +2064,9 @@ pub enum LazyConst<'tcx> {
     Evaluated(Const<'tcx>),
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(LAZY_CONST_SIZE: ::std::mem::size_of::<LazyConst<'static>>() == 56);
+
 impl<'tcx> LazyConst<'tcx> {
     pub fn map_evaluated<R>(self, f: impl FnOnce(Const<'tcx>) -> Option<R>) -> Option<R> {
         match self {
@@ -2089,6 +2093,9 @@ pub struct Const<'tcx> {
     pub val: ConstValue<'tcx>,
 }
 
+#[cfg(target_arch = "x86_64")]
+static_assert!(CONST_SIZE: ::std::mem::size_of::<Const<'static>>() == 48);
+
 impl<'tcx> Const<'tcx> {
     #[inline]
     pub fn from_scalar(
diff --git a/src/librustc/ty/subst.rs b/src/librustc/ty/subst.rs
index 64e7af815b4bf..7559ea90b1782 100644
--- a/src/librustc/ty/subst.rs
+++ b/src/librustc/ty/subst.rs
@@ -1,9 +1,9 @@
 // Type substitutions.
 
-use hir::def_id::DefId;
-use infer::canonical::Canonical;
-use ty::{self, Lift, List, Ty, TyCtxt};
-use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
+use crate::hir::def_id::DefId;
+use crate::infer::canonical::Canonical;
+use crate::ty::{self, Lift, List, Ty, TyCtxt};
+use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 
 use serialize::{self, Encodable, Encoder, Decodable, Decoder};
 use syntax_pos::{Span, DUMMY_SP};
@@ -171,7 +171,7 @@ impl<'a, 'gcx, 'tcx> Substs<'tcx> {
     /// Creates a `Substs` that maps each generic parameter to a higher-ranked
     /// var bound at index `0`. For types, we use a `BoundVar` index equal to
     /// the type parameter index. For regions, we use the `BoundRegion::BrNamed`
-    /// variant (which has a def-id).
+    /// variant (which has a `DefId`).
     pub fn bound_vars_for_item(
         tcx: TyCtxt<'a, 'gcx, 'tcx>,
         def_id: DefId
@@ -492,7 +492,7 @@ impl<'a, 'gcx, 'tcx> SubstFolder<'a, 'gcx, 'tcx> {
         self.shift_vars_through_binders(ty)
     }
 
-    /// It is sometimes necessary to adjust the debruijn indices during substitution. This occurs
+    /// It is sometimes necessary to adjust the De Bruijn indices during substitution. This occurs
     /// when we are substituting a type with escaping bound vars into a context where we have
     /// passed through binders. That's quite a mouthful. Let's see an example:
     ///
@@ -511,9 +511,9 @@ impl<'a, 'gcx, 'tcx> SubstFolder<'a, 'gcx, 'tcx> {
     ///
     /// Here the `'a` lifetime is bound in the outer function, but appears as an argument of the
     /// inner one. Therefore, that appearance will have a DebruijnIndex of 2, because we must skip
-    /// over the inner binder (remember that we count Debruijn indices from 1). However, in the
+    /// over the inner binder (remember that we count De Bruijn indices from 1). However, in the
     /// definition of `MetaFunc`, the binder is not visible, so the type `&'a int` will have a
-    /// debruijn index of 1. It's only during the substitution that we can see we must increase the
+    /// De Bruijn index of 1. It's only during the substitution that we can see we must increase the
     /// depth by 1 to account for the binder that we passed through.
     ///
     /// As a second example, consider this twist:
@@ -532,7 +532,7 @@ impl<'a, 'gcx, 'tcx> SubstFolder<'a, 'gcx, 'tcx> {
     ///                      DebruijnIndex of 2
     ///
     /// As indicated in the diagram, here the same type `&'a int` is substituted once, but in the
-    /// first case we do not increase the Debruijn index and in the second case we do. The reason
+    /// first case we do not increase the De Bruijn index and in the second case we do. The reason
     /// is that only in the second case have we passed through a fn binder.
     fn shift_vars_through_binders(&self, ty: Ty<'tcx>) -> Ty<'tcx> {
         debug!("shift_vars(ty={:?}, binders_passed={:?}, has_escaping_bound_vars={:?})",
@@ -565,7 +565,7 @@ pub struct UserSubsts<'tcx> {
     /// The substitutions for the item as given by the user.
     pub substs: &'tcx Substs<'tcx>,
 
-    /// The self-type, in the case of a `<T>::Item` path (when applied
+    /// The self type, in the case of a `<T>::Item` path (when applied
     /// to an inherent impl). See `UserSelfTy` below.
     pub user_self_ty: Option<UserSelfTy<'tcx>>,
 }
@@ -585,8 +585,8 @@ BraceStructLiftImpl! {
     }
 }
 
-/// Specifies the user-given self-type. In the case of a path that
-/// refers to a member in an inherent impl, this self-type is
+/// Specifies the user-given self type. In the case of a path that
+/// refers to a member in an inherent impl, this self type is
 /// sometimes needed to constrain the type parameters on the impl. For
 /// example, in this code:
 ///
@@ -596,11 +596,11 @@ BraceStructLiftImpl! {
 /// ```
 ///
 /// when you then have a path like `<Foo<&'static u32>>::method`,
-/// this struct would carry the def-id of the impl along with the
-/// self-type `Foo<u32>`. Then we can instantiate the parameters of
+/// this struct would carry the `DefId` of the impl along with the
+/// self type `Foo<u32>`. Then we can instantiate the parameters of
 /// the impl (with the substs from `UserSubsts`) and apply those to
-/// the self-type, giving `Foo<?A>`. Finally, we unify that with
-/// the self-type here, which contains `?A` to be `&'static u32`
+/// the self type, giving `Foo<?A>`. Finally, we unify that with
+/// the self type here, which contains `?A` to be `&'static u32`
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub struct UserSelfTy<'tcx> {
     pub impl_def_id: DefId,
diff --git a/src/librustc/ty/trait_def.rs b/src/librustc/ty/trait_def.rs
index 37ec560d6c19f..9ce8bf2e60a31 100644
--- a/src/librustc/ty/trait_def.rs
+++ b/src/librustc/ty/trait_def.rs
@@ -1,11 +1,11 @@
-use hir;
-use hir::def_id::DefId;
-use hir::map::DefPathHash;
-use ich::{self, StableHashingContext};
-use traits::specialization_graph;
-use ty::fast_reject;
-use ty::fold::TypeFoldable;
-use ty::{Ty, TyCtxt};
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::hir::map::DefPathHash;
+use crate::ich::{self, StableHashingContext};
+use crate::traits::specialization_graph;
+use crate::ty::fast_reject;
+use crate::ty::fold::TypeFoldable;
+use crate::ty::{Ty, TyCtxt};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher,
@@ -39,7 +39,7 @@ pub struct TraitDef {
 #[derive(Default)]
 pub struct TraitImpls {
     blanket_impls: Vec<DefId>,
-    /// Impls indexed by their simplified self-type, for fast lookup.
+    /// Impls indexed by their simplified self type, for fast lookup.
     non_blanket_impls: FxHashMap<fast_reject::SimplifiedType, Vec<DefId>>,
 }
 
@@ -84,7 +84,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     /// Iterate over every impl that could possibly match the
-    /// self-type `self_ty`.
+    /// self type `self_ty`.
     pub fn for_each_relevant_impl<F: FnMut(DefId)>(self,
                                                    def_id: DefId,
                                                    self_ty: Ty<'tcx>,
@@ -134,7 +134,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Return a vector containing all impls
+    /// Returns a vector containing all impls
     pub fn all_impls(self, def_id: DefId) -> Vec<DefId> {
         let impls = self.trait_impls_of(def_id);
 
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index e989ef823e979..1ba7c3bba797c 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -1,18 +1,18 @@
-//! misc. type-system utilities too small to deserve their own file
-
-use hir::def::Def;
-use hir::def_id::DefId;
-use hir::map::DefPathData;
-use hir::{self, Node};
-use ich::NodeIdHashingMode;
-use traits::{self, ObligationCause};
-use ty::{self, Ty, TyCtxt, GenericParamDefKind, TypeFoldable};
-use ty::subst::{Subst, Substs, UnpackedKind};
-use ty::query::TyCtxtAt;
-use ty::TyKind::*;
-use ty::layout::{Integer, IntegerExt};
-use util::common::ErrorReported;
-use middle::lang_items;
+//! Miscellaneous type-system utilities that are too small to deserve their own modules.
+
+use crate::hir::def::Def;
+use crate::hir::def_id::DefId;
+use crate::hir::map::DefPathData;
+use crate::hir::{self, Node};
+use crate::ich::NodeIdHashingMode;
+use crate::traits::{self, ObligationCause};
+use crate::ty::{self, Ty, TyCtxt, GenericParamDefKind, TypeFoldable};
+use crate::ty::subst::{Subst, Substs, UnpackedKind};
+use crate::ty::query::TyCtxtAt;
+use crate::ty::TyKind::*;
+use crate::ty::layout::{Integer, IntegerExt};
+use crate::util::common::ErrorReported;
+use crate::middle::lang_items;
 
 use rustc_data_structures::stable_hasher::{StableHasher, HashStable};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
@@ -23,7 +23,7 @@ use syntax_pos::{Span, DUMMY_SP};
 
 #[derive(Copy, Clone, Debug)]
 pub struct Discr<'tcx> {
-    /// bit representation of the discriminant, so `-128i8` is `0xFF_u128`
+    /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`).
     pub val: u128,
     pub ty: Ty<'tcx>
 }
@@ -46,7 +46,7 @@ impl<'tcx> fmt::Display for Discr<'tcx> {
 }
 
 impl<'tcx> Discr<'tcx> {
-    /// Adds 1 to the value and wraps around if the maximum for the type is reached
+    /// Adds `1` to the value and wraps around if the maximum for the type is reached.
     pub fn wrap_incr<'a, 'gcx>(self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Self {
         self.checked_add(tcx, 1).0
     }
@@ -342,9 +342,9 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     ///
     /// Requires that trait definitions have been processed so that we can
     /// elaborate predicates and walk supertraits.
-    ///
-    /// FIXME callers may only have a &[Predicate], not a Vec, so that's
-    /// what this code should accept.
+    //
+    // FIXME: callers may only have a `&[Predicate]`, not a `Vec`, so that's
+    // what this code should accept.
     pub fn required_region_bounds(self,
                                   erased_self_ty: Ty<'tcx>,
                                   predicates: Vec<ty::Predicate<'tcx>>)
@@ -402,7 +402,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             return None;
         };
 
-        ty::query::queries::coherent_trait::ensure(self, drop_trait);
+        self.ensure().coherent_trait(drop_trait);
 
         let mut dtor_did = None;
         let ty = self.type_of(adt_did);
@@ -417,7 +417,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         Some(ty::Destructor { did: dtor_did? })
     }
 
-    /// Return the set of types that are required to be alive in
+    /// Returns the set of types that are required to be alive in
     /// order to run the destructor of `def` (see RFCs 769 and
     /// 1238).
     ///
@@ -507,17 +507,17 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         result
     }
 
-    /// True if `def_id` refers to a closure (e.g., `|x| x * 2`). Note
-    /// that closures have a def-id, but the closure *expression* also
+    /// Returns `true` if `def_id` refers to a closure (e.g., `|x| x * 2`). Note
+    /// that closures have a `DefId`, but the closure *expression* also
     /// has a `HirId` that is located within the context where the
     /// closure appears (and, sadly, a corresponding `NodeId`, since
     /// those are not yet phased out). The parent of the closure's
-    /// def-id will also be the context where it appears.
+    /// `DefId` will also be the context where it appears.
     pub fn is_closure(self, def_id: DefId) -> bool {
         self.def_key(def_id).disambiguated_data.data == DefPathData::ClosureExpr
     }
 
-    /// True if `def_id` refers to a trait (i.e., `trait Foo { ... }`).
+    /// Returns `true` if `def_id` refers to a trait (i.e., `trait Foo { ... }`).
     pub fn is_trait(self, def_id: DefId) -> bool {
         if let DefPathData::Trait(_) = self.def_key(def_id).disambiguated_data.data {
             true
@@ -526,17 +526,27 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// True if this def-id refers to the implicit constructor for
-    /// a tuple struct like `struct Foo(u32)`.
+    /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`),
+    /// and `false` otherwise.
+    pub fn is_trait_alias(self, def_id: DefId) -> bool {
+        if let DefPathData::TraitAlias(_) = self.def_key(def_id).disambiguated_data.data {
+            true
+        } else {
+            false
+        }
+    }
+
+    /// Returns `true` if this `DefId` refers to the implicit constructor for
+    /// a tuple struct like `struct Foo(u32)`, and `false` otherwise.
     pub fn is_struct_constructor(self, def_id: DefId) -> bool {
         self.def_key(def_id).disambiguated_data.data == DefPathData::StructCtor
     }
 
     /// Given the `DefId` of a fn or closure, returns the `DefId` of
     /// the innermost fn item that the closure is contained within.
-    /// This is a significant def-id because, when we do
+    /// This is a significant `DefId` because, when we do
     /// type-checking, we type-check this fn item and all of its
-    /// (transitive) closures together.  Therefore, when we fetch the
+    /// (transitive) closures together. Therefore, when we fetch the
     /// `typeck_tables_of` the closure, for example, we really wind up
     /// fetching the `typeck_tables_of` the enclosing fn item.
     pub fn closure_base_def_id(self, def_id: DefId) -> DefId {
@@ -549,10 +559,10 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         def_id
     }
 
-    /// Given the def-id and substs a closure, creates the type of
+    /// Given the `DefId` and substs a closure, creates the type of
     /// `self` argument that the closure expects. For example, for a
     /// `Fn` closure, this would return a reference type `&T` where
-    /// `T=closure_ty`.
+    /// `T = closure_ty`.
     ///
     /// Returns `None` if this closure's kind has not yet been inferred.
     /// This should only be possible during type checking.
@@ -576,7 +586,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         Some(ty::Binder::bind(env_ty))
     }
 
-    /// Given the def-id of some item that has no type parameters, make
+    /// Given the `DefId` of some item that has no type parameters, make
     /// a suitable "empty substs" for it.
     pub fn empty_substs_for_def_id(self, item_def_id: DefId) -> &'tcx Substs<'tcx> {
         Substs::for_item(self, item_def_id, |param, _| {
@@ -589,7 +599,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// Return whether the node pointed to by def_id is a static item, and its mutability
+    /// Returns `true` if the node pointed to by `def_id` is a static item, and its mutability.
     pub fn is_static(&self, def_id: DefId) -> Option<hir::Mutability> {
         if let Some(node) = self.hir().get_if_local(def_id) {
             match node {
@@ -721,7 +731,7 @@ impl<'a, 'tcx> ty::TyS<'tcx> {
 
     /// Checks whether values of this type `T` implement the `Freeze`
     /// trait -- frozen types are those that do not contain a
-    /// `UnsafeCell` anywhere.  This is a language concept used to
+    /// `UnsafeCell` anywhere. This is a language concept used to
     /// distinguish "true immutability", which is relevant to
     /// optimization as well as the rules around static values. Note
     /// that the `Freeze` trait is not exposed to end users and is
@@ -745,7 +755,7 @@ impl<'a, 'tcx> ty::TyS<'tcx> {
                       tcx: TyCtxt<'a, 'tcx, 'tcx>,
                       param_env: ty::ParamEnv<'tcx>)
                       -> bool {
-        tcx.needs_drop_raw(param_env.and(self))
+        tcx.needs_drop_raw(param_env.and(self)).0
     }
 
     pub fn same_type(a: Ty<'tcx>, b: Ty<'tcx>) -> bool {
@@ -982,29 +992,22 @@ fn is_freeze_raw<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         ))
 }
 
+#[derive(Clone)]
+pub struct NeedsDrop(pub bool);
+
 fn needs_drop_raw<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                             query: ty::ParamEnvAnd<'tcx, Ty<'tcx>>)
-                            -> bool
+                            -> NeedsDrop
 {
     let (param_env, ty) = query.into_parts();
 
     let needs_drop = |ty: Ty<'tcx>| -> bool {
-        tcx.try_needs_drop_raw(DUMMY_SP, param_env.and(ty)).unwrap_or_else(|mut bug| {
-            // Cycles should be reported as an error by `check_representable`.
-            //
-            // Consider the type as not needing drop in the meanwhile to
-            // avoid further errors.
-            //
-            // In case we forgot to emit a bug elsewhere, delay our
-            // diagnostic to get emitted as a compiler bug.
-            bug.delay_as_bug();
-            false
-        })
+        tcx.needs_drop_raw(param_env.and(ty)).0
     };
 
     assert!(!ty.needs_infer());
 
-    match ty.sty {
+    NeedsDrop(match ty.sty {
         // Fast-path for primitive types
         ty::Infer(ty::FreshIntTy(_)) | ty::Infer(ty::FreshFloatTy(_)) |
         ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Never |
@@ -1062,7 +1065,7 @@ fn needs_drop_raw<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             def.variants.iter().any(
                 |variant| variant.fields.iter().any(
                     |field| needs_drop(field.ty(tcx, substs)))),
-    }
+    })
 }
 
 pub enum ExplicitSelf<'tcx> {
diff --git a/src/librustc/ty/walk.rs b/src/librustc/ty/walk.rs
index 6887d092fcd62..126f5290af513 100644
--- a/src/librustc/ty/walk.rs
+++ b/src/librustc/ty/walk.rs
@@ -1,7 +1,7 @@
 //! An iterator over the type substructure.
 //! WARNING: this does not keep track of the region depth.
 
-use ty::{self, Ty};
+use crate::ty::{self, Ty};
 use smallvec::{self, SmallVec};
 
 // The TypeWalker's stack is hot enough that it's worth going to some effort to
diff --git a/src/librustc/ty/wf.rs b/src/librustc/ty/wf.rs
index ef68394029680..282bf1219fa5c 100644
--- a/src/librustc/ty/wf.rs
+++ b/src/librustc/ty/wf.rs
@@ -1,12 +1,12 @@
-use hir::def_id::DefId;
-use infer::InferCtxt;
-use ty::subst::Substs;
-use traits;
-use ty::{self, ToPredicate, Ty, TyCtxt, TypeFoldable};
+use crate::hir;
+use crate::hir::def_id::DefId;
+use crate::infer::InferCtxt;
+use crate::ty::subst::Substs;
+use crate::traits;
+use crate::ty::{self, ToPredicate, Ty, TyCtxt, TypeFoldable};
 use std::iter::once;
-use syntax::ast;
 use syntax_pos::Span;
-use middle::lang_items;
+use crate::middle::lang_items;
 
 /// Returns the set of obligations needed to make `ty` well-formed.
 /// If `ty` contains unresolved inference variables, this may include
@@ -16,7 +16,7 @@ use middle::lang_items;
 /// say "$0 is WF if $0 is WF".
 pub fn obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
                                    param_env: ty::ParamEnv<'tcx>,
-                                   body_id: ast::NodeId,
+                                   body_id: hir::HirId,
                                    ty: Ty<'tcx>,
                                    span: Span)
                                    -> Option<Vec<traits::PredicateObligation<'tcx>>>
@@ -42,7 +42,7 @@ pub fn obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
 /// if `Bar: Eq`.
 pub fn trait_obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
                                          param_env: ty::ParamEnv<'tcx>,
-                                         body_id: ast::NodeId,
+                                         body_id: hir::HirId,
                                          trait_ref: &ty::TraitRef<'tcx>,
                                          span: Span)
                                          -> Vec<traits::PredicateObligation<'tcx>>
@@ -54,7 +54,7 @@ pub fn trait_obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
 
 pub fn predicate_obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
                                              param_env: ty::ParamEnv<'tcx>,
-                                             body_id: ast::NodeId,
+                                             body_id: hir::HirId,
                                              predicate: &ty::Predicate<'tcx>,
                                              span: Span)
                                              -> Vec<traits::PredicateObligation<'tcx>>
@@ -103,7 +103,7 @@ pub fn predicate_obligations<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
 struct WfPredicates<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
     span: Span,
     out: Vec<traits::PredicateObligation<'tcx>>,
 }
@@ -227,7 +227,7 @@ impl<'a, 'gcx, 'tcx> WfPredicates<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Push new obligations into `out`. Returns true if it was able
+    /// Pushes new obligations into `out`. Returns `true` if it was able
     /// to generate all the predicates needed to validate that `ty0`
     /// is WF. Returns false if `ty0` is an unresolved type variable,
     /// in which case we are not able to simplify at all.
@@ -502,7 +502,7 @@ impl<'a, 'gcx, 'tcx> WfPredicates<'a, 'gcx, 'tcx> {
     }
 }
 
-/// Given an object type like `SomeTrait+Send`, computes the lifetime
+/// Given an object type like `SomeTrait + Send`, computes the lifetime
 /// bounds that must hold on the elided self type. These are derived
 /// from the declarations of `SomeTrait`, `Send`, and friends -- if
 /// they declare `trait SomeTrait : 'static`, for example, then
diff --git a/src/librustc/util/bug.rs b/src/librustc/util/bug.rs
index 7698f5ece98cc..02ddfab6d826e 100644
--- a/src/librustc/util/bug.rs
+++ b/src/librustc/util/bug.rs
@@ -1,6 +1,6 @@
 // These functions are used by macro expansion for bug! and span_bug!
 
-use ty::tls;
+use crate::ty::tls;
 use std::fmt;
 use syntax_pos::{Span, MultiSpan};
 
diff --git a/src/librustc/util/common.rs b/src/librustc/util/common.rs
index cc0ca165053d3..dd635e5c946f0 100644
--- a/src/librustc/util/common.rs
+++ b/src/librustc/util/common.rs
@@ -12,10 +12,10 @@ use std::time::{Duration, Instant};
 
 use std::sync::mpsc::{Sender};
 use syntax_pos::{SpanData};
-use ty::TyCtxt;
-use dep_graph::{DepNode};
+use crate::ty::TyCtxt;
+use crate::dep_graph::{DepNode};
 use lazy_static;
-use session::Session;
+use crate::session::Session;
 
 // The name of the associated type for `Fn` return types
 pub const FN_OUTPUT_NAME: &str = "Output";
@@ -63,11 +63,11 @@ pub fn install_panic_hook() {
 /// Parameters to the `Dump` variant of type `ProfileQueriesMsg`.
 #[derive(Clone,Debug)]
 pub struct ProfQDumpParams {
-    /// A base path for the files we will dump
+    /// A base path for the files we will dump.
     pub path:String,
-    /// To ensure that the compiler waits for us to finish our dumps
+    /// To ensure that the compiler waits for us to finish our dumps.
     pub ack:Sender<()>,
-    /// toggle dumping a log file with every `ProfileQueriesMsg`
+    /// Toggle dumping a log file with every `ProfileQueriesMsg`.
     pub dump_profq_msg_log:bool,
 }
 
@@ -131,7 +131,7 @@ pub fn time_depth() -> usize {
     TIME_DEPTH.with(|slot| slot.get())
 }
 
-/// Set the current depth of `time()` calls. The idea is to call
+/// Sets the current depth of `time()` calls. The idea is to call
 /// `set_time_depth()` with the result from `time_depth()` in the
 /// parent thread.
 pub fn set_time_depth(depth: usize) {
diff --git a/src/librustc/util/nodemap.rs b/src/librustc/util/nodemap.rs
index fe6ab075a1a8a..63c7b76d1b6a5 100644
--- a/src/librustc/util/nodemap.rs
+++ b/src/librustc/util/nodemap.rs
@@ -1,7 +1,7 @@
-//! An efficient hash map for node IDs
+//! An efficient hash map for `NodeId`s.
 
-use hir::def_id::DefId;
-use hir::{HirId, ItemLocalId};
+use crate::hir::def_id::DefId;
+use crate::hir::{HirId, ItemLocalId};
 use syntax::ast;
 
 pub use rustc_data_structures::fx::FxHashMap;
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index 04e571863d42f..768fd02e8238a 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -1,15 +1,15 @@
-use hir::def_id::DefId;
-use hir::map::definitions::DefPathData;
-use middle::region;
-use ty::subst::{self, Subst};
-use ty::{BrAnon, BrEnv, BrFresh, BrNamed};
-use ty::{Bool, Char, Adt};
-use ty::{Error, Str, Array, Slice, Float, FnDef, FnPtr};
-use ty::{Param, Bound, RawPtr, Ref, Never, Tuple};
-use ty::{Closure, Generator, GeneratorWitness, Foreign, Projection, Opaque};
-use ty::{Placeholder, UnnormalizedProjection, Dynamic, Int, Uint, Infer};
-use ty::{self, Ty, TyCtxt, TypeFoldable, GenericParamCount, GenericParamDefKind};
-use util::nodemap::FxHashSet;
+use crate::hir::def_id::DefId;
+use crate::hir::map::definitions::DefPathData;
+use crate::middle::region;
+use crate::ty::subst::{self, Subst};
+use crate::ty::{BrAnon, BrEnv, BrFresh, BrNamed};
+use crate::ty::{Bool, Char, Adt};
+use crate::ty::{Error, Str, Array, Slice, Float, FnDef, FnPtr};
+use crate::ty::{Param, Bound, RawPtr, Ref, Never, Tuple};
+use crate::ty::{Closure, Generator, GeneratorWitness, Foreign, Projection, Opaque};
+use crate::ty::{Placeholder, UnnormalizedProjection, Dynamic, Int, Uint, Infer};
+use crate::ty::{self, Ty, TyCtxt, TypeFoldable, GenericParamCount, GenericParamDefKind};
+use crate::util::nodemap::FxHashSet;
 
 use std::cell::Cell;
 use std::fmt;
@@ -18,23 +18,23 @@ use std::usize;
 use rustc_target::spec::abi::Abi;
 use syntax::ast::CRATE_NODE_ID;
 use syntax::symbol::{Symbol, InternedString};
-use hir;
+use crate::hir;
 
 /// The "region highlights" are used to control region printing during
 /// specific error messages. When a "region highlight" is enabled, it
 /// gives an alternate way to print specific regions. For now, we
-/// always print those regions using a number, so something like `'0`.
+/// always print those regions using a number, so something like "`'0`".
 ///
 /// Regions not selected by the region highlight mode are presently
 /// unaffected.
 #[derive(Copy, Clone, Default)]
 pub struct RegionHighlightMode {
-    /// If enabled, when we see the selected region, use `"'N"`
+    /// If enabled, when we see the selected region, use "`'N`"
     /// instead of the ordinary behavior.
     highlight_regions: [Option<(ty::RegionKind, usize)>; 3],
 
     /// If enabled, when printing a "free region" that originated from
-    /// the given `ty::BoundRegion`, print it as `'1`. Free regions that would ordinarily
+    /// the given `ty::BoundRegion`, print it as "`'1`". Free regions that would ordinarily
     /// have names print as normal.
     ///
     /// This is used when you have a signature like `fn foo(x: &u32,
@@ -51,12 +51,12 @@ thread_local! {
 }
 
 impl RegionHighlightMode {
-    /// Read and return current region highlight settings (accesses thread-local state).a
+    /// Reads and returns the current region highlight settings (accesses thread-local state).
     pub fn get() -> Self {
         REGION_HIGHLIGHT_MODE.with(|c| c.get())
     }
 
-    /// Internal helper to update current settings during the execution of `op`.
+    // Internal helper to update current settings during the execution of `op`.
     fn set<R>(
         old_mode: Self,
         new_mode: Self,
@@ -70,8 +70,8 @@ impl RegionHighlightMode {
         })
     }
 
-    /// If `region` and `number` are both `Some`, invoke
-    /// `highlighting_region`. Otherwise, just invoke `op` directly.
+    /// If `region` and `number` are both `Some`, invokes
+    /// `highlighting_region`; otherwise, just invokes `op` directly.
     pub fn maybe_highlighting_region<R>(
         region: Option<ty::Region<'_>>,
         number: Option<usize>,
@@ -86,8 +86,8 @@ impl RegionHighlightMode {
         op()
     }
 
-    /// During the execution of `op`, highlight the region inference
-    /// vairable `vid` as `'N`.  We can only highlight one region vid
+    /// During the execution of `op`, highlights the region inference
+    /// variable `vid` as `'N`. We can only highlight one region `vid`
     /// at a time.
     pub fn highlighting_region<R>(
         region: ty::Region<'_>,
@@ -109,7 +109,7 @@ impl RegionHighlightMode {
         Self::set(old_mode, new_mode, op)
     }
 
-    /// Convenience wrapper for `highlighting_region`
+    /// Convenience wrapper for `highlighting_region`.
     pub fn highlighting_region_vid<R>(
         vid: ty::RegionVid,
         number: usize,
@@ -118,7 +118,7 @@ impl RegionHighlightMode {
         Self::highlighting_region(&ty::ReVar(vid), number, op)
     }
 
-    /// Returns true if any placeholders are highlighted.
+    /// Returns `true` if any placeholders are highlighted, and `false` otherwise.
     fn any_region_vids_highlighted(&self) -> bool {
         Self::get()
             .highlight_regions
@@ -129,8 +129,7 @@ impl RegionHighlightMode {
             })
     }
 
-    /// Returns `Some(n)` with the number to use for the given region,
-    /// if any.
+    /// Returns `Some(n)` with the number to use for the given region, if any.
     fn region_highlighted(&self, region: ty::Region<'_>) -> Option<usize> {
         Self::get()
             .highlight_regions
@@ -143,7 +142,7 @@ impl RegionHighlightMode {
     }
 
     /// During the execution of `op`, highlight the given bound
-    /// region. We can only highlight one bound region at a time.  See
+    /// region. We can only highlight one bound region at a time. See
     /// the field `highlight_bound_region` for more detailed notes.
     pub fn highlighting_bound_region<R>(
         br: ty::BoundRegion,
@@ -162,7 +161,7 @@ impl RegionHighlightMode {
         )
     }
 
-    /// Returns true if any placeholders are highlighted.
+    /// Returns `true` if any placeholders are highlighted, and `false` otherwise.
     pub fn any_placeholders_highlighted(&self) -> bool {
         Self::get()
             .highlight_regions
@@ -173,7 +172,7 @@ impl RegionHighlightMode {
             })
     }
 
-    /// Returns `Some(N)` if the placeholder `p` is highlighted to print as `'N`.
+    /// Returns `Some(N)` if the placeholder `p` is highlighted to print as "`'N`".
     pub fn placeholder_highlight(&self, p: ty::PlaceholderRegion) -> Option<usize> {
         self.region_highlighted(&ty::RePlaceholder(p))
     }
@@ -409,6 +408,7 @@ impl PrintContext {
                     DefPathData::AssocTypeInImpl(_) |
                     DefPathData::AssocExistentialInImpl(_) |
                     DefPathData::Trait(_) |
+                    DefPathData::TraitAlias(_) |
                     DefPathData::Impl |
                     DefPathData::TypeNs(_) => {
                         break;
@@ -425,6 +425,7 @@ impl PrintContext {
                     DefPathData::ClosureExpr |
                     DefPathData::TypeParam(_) |
                     DefPathData::LifetimeParam(_) |
+                    DefPathData::ConstParam(_) |
                     DefPathData::Field(_) |
                     DefPathData::StructCtor |
                     DefPathData::AnonConst |
@@ -800,7 +801,7 @@ impl fmt::Debug for ty::UpvarId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "UpvarId({:?};`{}`;{:?})",
                self.var_path.hir_id,
-               ty::tls::with(|tcx| tcx.hir().name(tcx.hir().hir_to_node_id(self.var_path.hir_id))),
+               ty::tls::with(|tcx| tcx.hir().name_by_hir_id(self.var_path.hir_id)),
                self.closure_expr_id)
     }
 }
@@ -1429,6 +1430,15 @@ define_print! {
                         }
                     }
 
+                    if cx.is_verbose {
+                        write!(
+                            f,
+                            " closure_kind_ty={:?} closure_sig_ty={:?}",
+                            substs.closure_kind_ty(did, tcx),
+                            substs.closure_sig_ty(did, tcx),
+                        )?;
+                    }
+
                     write!(f, "]")
                 }),
                 Array(ty, sz) => {
diff --git a/src/librustc/util/profiling.rs b/src/librustc/util/profiling.rs
index d31a06d6cb82d..c90bd12a3100f 100644
--- a/src/librustc/util/profiling.rs
+++ b/src/librustc/util/profiling.rs
@@ -1,146 +1,168 @@
-use session::config::Options;
-
+use std::collections::{BTreeMap, HashMap};
 use std::fs;
-use std::io::{self, StderrLock, Write};
+use std::io::{self, Write};
+use std::thread::ThreadId;
 use std::time::Instant;
 
-macro_rules! define_categories {
-    ($($name:ident,)*) => {
-        #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-        pub enum ProfileCategory {
-            $($name),*
-        }
+use crate::session::config::{Options, OptLevel};
 
-        #[allow(nonstandard_style)]
-        struct Categories<T> {
-            $($name: T),*
-        }
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Ord, PartialOrd)]
+pub enum ProfileCategory {
+    Parsing,
+    Expansion,
+    TypeChecking,
+    BorrowChecking,
+    Codegen,
+    Linking,
+    Other,
+}
 
-        impl<T: Default> Categories<T> {
-            fn new() -> Categories<T> {
-                Categories {
-                    $($name: T::default()),*
-                }
-            }
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ProfilerEvent {
+    QueryStart { query_name: &'static str, category: ProfileCategory, time: Instant },
+    QueryEnd { query_name: &'static str, category: ProfileCategory, time: Instant },
+    GenericActivityStart { category: ProfileCategory, time: Instant },
+    GenericActivityEnd { category: ProfileCategory, time: Instant },
+    QueryCacheHit { query_name: &'static str, category: ProfileCategory },
+    QueryCount { query_name: &'static str, category: ProfileCategory, count: usize },
+    IncrementalLoadResultStart { query_name: &'static str, time: Instant },
+    IncrementalLoadResultEnd { query_name: &'static str, time: Instant },
+    QueryBlockedStart { query_name: &'static str, category: ProfileCategory, time: Instant },
+    QueryBlockedEnd { query_name: &'static str, category: ProfileCategory, time: Instant },
+}
+
+impl ProfilerEvent {
+    fn is_start_event(&self) -> bool {
+        use self::ProfilerEvent::*;
+
+        match self {
+            QueryStart { .. } |
+            GenericActivityStart { .. } |
+            IncrementalLoadResultStart { .. } |
+            QueryBlockedStart { .. } => true,
+
+            QueryEnd { .. } |
+            GenericActivityEnd { .. } |
+            QueryCacheHit { .. } |
+            QueryCount { .. } |
+            IncrementalLoadResultEnd { .. } |
+            QueryBlockedEnd { .. } => false,
         }
+    }
+}
 
-        impl<T> Categories<T> {
-            fn get(&self, category: ProfileCategory) -> &T {
-                match category {
-                    $(ProfileCategory::$name => &self.$name),*
-                }
-            }
+pub struct SelfProfiler {
+    events: HashMap<ThreadId, Vec<ProfilerEvent>>,
+}
 
-            fn set(&mut self, category: ProfileCategory, value: T) {
-                match category {
-                    $(ProfileCategory::$name => self.$name = value),*
-                }
-            }
+struct CategoryResultData {
+    query_times: BTreeMap<&'static str, u64>,
+    query_cache_stats: BTreeMap<&'static str, (u64, u64)>, //(hits, total)
+}
+
+impl CategoryResultData {
+    fn new() -> CategoryResultData {
+        CategoryResultData {
+            query_times: BTreeMap::new(),
+            query_cache_stats: BTreeMap::new(),
         }
+    }
 
-        struct CategoryData {
-            times: Categories<u64>,
-            query_counts: Categories<(u64, u64)>,
+    fn total_time(&self) -> u64 {
+        self.query_times.iter().map(|(_, time)| time).sum()
+    }
+
+    fn total_cache_data(&self) -> (u64, u64) {
+        let (mut hits, mut total) = (0, 0);
+
+        for (_, (h, t)) in &self.query_cache_stats {
+            hits += h;
+            total += t;
         }
 
-        impl CategoryData {
-            fn new() -> CategoryData {
-                CategoryData {
-                    times: Categories::new(),
-                    query_counts: Categories::new(),
-                }
-            }
+        (hits, total)
+    }
+}
 
-            fn print(&self, lock: &mut StderrLock<'_>) {
-                writeln!(lock, "| Phase            | Time (ms)      \
-                                | Time (%) | Queries        | Hits (%)")
-                    .unwrap();
-                writeln!(lock, "| ---------------- | -------------- \
-                                | -------- | -------------- | --------")
-                    .unwrap();
-
-                let total_time = ($(self.times.$name + )* 0) as f32;
-
-                $(
-                    let (hits, computed) = self.query_counts.$name;
-                    let total = hits + computed;
-                    let (hits, total) = if total > 0 {
-                        (format!("{:.2}",
-                        (((hits as f32) / (total as f32)) * 100.0)), total.to_string())
-                    } else {
-                        (String::new(), String::new())
-                    };
+impl Default for CategoryResultData {
+    fn default() -> CategoryResultData {
+        CategoryResultData::new()
+    }
+}
 
-                    writeln!(
-                        lock,
-                        "| {0: <16} | {1: <14} | {2: <8.2} | {3: <14} | {4: <8}",
-                        stringify!($name),
-                        self.times.$name / 1_000_000,
-                        ((self.times.$name as f32) / total_time) * 100.0,
-                        total,
-                        hits,
-                    ).unwrap();
-                )*
-            }
+struct CalculatedResults {
+    categories: BTreeMap<ProfileCategory, CategoryResultData>,
+    crate_name: Option<String>,
+    optimization_level: OptLevel,
+    incremental: bool,
+    verbose: bool,
+}
 
-            fn json(&self) -> String {
-                let mut json = String::from("[");
-
-                $(
-                    let (hits, computed) = self.query_counts.$name;
-                    let total = hits + computed;
-
-                    //normalize hits to 0%
-                    let hit_percent =
-                        if total > 0 {
-                            ((hits as f32) / (total as f32)) * 100.0
-                        } else {
-                            0.0
-                        };
-
-                    json.push_str(&format!(
-                        "{{ \"category\": \"{}\", \"time_ms\": {},\
-                            \"query_count\": {}, \"query_hits\": {} }},",
-                        stringify!($name),
-                        self.times.$name / 1_000_000,
-                        total,
-                        format!("{:.2}", hit_percent)
-                    ));
-                )*
+impl CalculatedResults {
+    fn new() -> CalculatedResults {
+        CalculatedResults {
+            categories: BTreeMap::new(),
+            crate_name: None,
+            optimization_level: OptLevel::No,
+            incremental: false,
+            verbose: false,
+        }
+    }
 
-                //remove the trailing ',' character
-                json.pop();
+    fn consolidate(mut cr1: CalculatedResults, cr2: CalculatedResults) -> CalculatedResults {
+        for (category, data) in cr2.categories {
+            let cr1_data = cr1.categories.entry(category).or_default();
 
-                json.push(']');
+            for (query, time) in data.query_times {
+                *cr1_data.query_times.entry(query).or_default() += time;
+            }
 
-                json
+            for (query, (hits, total)) in data.query_cache_stats {
+                let (h, t) = cr1_data.query_cache_stats.entry(query).or_insert((0, 0));
+                *h += hits;
+                *t += total;
             }
         }
+
+        cr1
+    }
+
+    fn total_time(&self) -> u64 {
+        self.categories.iter().map(|(_, data)| data.total_time()).sum()
+    }
+
+    fn with_options(mut self, opts: &Options) -> CalculatedResults {
+        self.crate_name = opts.crate_name.clone();
+        self.optimization_level = opts.optimize;
+        self.incremental = opts.incremental.is_some();
+        self.verbose = opts.debugging_opts.verbose;
+
+        self
     }
 }
 
-define_categories! {
-    Parsing,
-    Expansion,
-    TypeChecking,
-    BorrowChecking,
-    Codegen,
-    Linking,
-    Other,
+fn time_between_ns(start: Instant, end: Instant) -> u64 {
+    if start < end {
+        let time = end - start;
+        (time.as_secs() * 1_000_000_000) + (time.subsec_nanos() as u64)
+    } else {
+        debug!("time_between_ns: ignorning instance of end < start");
+        0
+    }
 }
 
-pub struct SelfProfiler {
-    timer_stack: Vec<ProfileCategory>,
-    data: CategoryData,
-    current_timer: Instant,
+fn calculate_percent(numerator: u64, denominator: u64) -> f32 {
+    if denominator > 0 {
+        ((numerator as f32) / (denominator as f32)) * 100.0
+    } else {
+        0.0
+    }
 }
 
 impl SelfProfiler {
     pub fn new() -> SelfProfiler {
         let mut profiler = SelfProfiler {
-            timer_stack: Vec::new(),
-            data: CategoryData::new(),
-            current_timer: Instant::now(),
+            events: HashMap::new(),
         };
 
         profiler.start_activity(ProfileCategory::Other);
@@ -148,104 +170,301 @@ impl SelfProfiler {
         profiler
     }
 
+    #[inline]
     pub fn start_activity(&mut self, category: ProfileCategory) {
-        match self.timer_stack.last().cloned() {
-            None => {
-                self.current_timer = Instant::now();
-            },
-            Some(current_category) if current_category == category => {
-                //since the current category is the same as the new activity's category,
-                //we don't need to do anything with the timer, we just need to push it on the stack
-            }
-            Some(current_category) => {
-                let elapsed = self.stop_timer();
+        self.record(ProfilerEvent::GenericActivityStart {
+            category,
+            time: Instant::now(),
+        })
+    }
 
-                //record the current category's time
-                let new_time = self.data.times.get(current_category) + elapsed;
-                self.data.times.set(current_category, new_time);
-            }
-        }
+    #[inline]
+    pub fn end_activity(&mut self, category: ProfileCategory) {
+        self.record(ProfilerEvent::GenericActivityEnd {
+            category,
+            time: Instant::now(),
+        })
+    }
 
-        //push the new category
-        self.timer_stack.push(category);
+    #[inline]
+    pub fn record_computed_queries(
+        &mut self,
+        query_name: &'static str,
+        category: ProfileCategory,
+        count: usize)
+        {
+        self.record(ProfilerEvent::QueryCount {
+            query_name,
+            category,
+            count,
+        })
     }
 
-    pub fn record_computed_queries(&mut self, category: ProfileCategory, count: usize) {
-        let (hits, computed) = *self.data.query_counts.get(category);
-        self.data.query_counts.set(category, (hits, computed + count as u64));
+    #[inline]
+    pub fn record_query_hit(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryCacheHit {
+            query_name,
+            category,
+        })
     }
 
-    pub fn record_query_hit(&mut self, category: ProfileCategory) {
-        let (hits, computed) = *self.data.query_counts.get(category);
-        self.data.query_counts.set(category, (hits + 1, computed));
+    #[inline]
+    pub fn start_query(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryStart {
+            query_name,
+            category,
+            time: Instant::now(),
+        });
     }
 
-    pub fn end_activity(&mut self, category: ProfileCategory) {
-        match self.timer_stack.pop() {
-            None => bug!("end_activity() was called but there was no running activity"),
-            Some(c) =>
-                assert!(
-                    c == category,
-                    "end_activity() was called but a different activity was running"),
+    #[inline]
+    pub fn end_query(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryEnd {
+            query_name,
+            category,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn incremental_load_result_start(&mut self, query_name: &'static str) {
+        self.record(ProfilerEvent::IncrementalLoadResultStart {
+            query_name,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn incremental_load_result_end(&mut self, query_name: &'static str) {
+        self.record(ProfilerEvent::IncrementalLoadResultEnd {
+            query_name,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn query_blocked_start(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryBlockedStart {
+            query_name,
+            category,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    pub fn query_blocked_end(&mut self, query_name: &'static str, category: ProfileCategory) {
+        self.record(ProfilerEvent::QueryBlockedEnd {
+            query_name,
+            category,
+            time: Instant::now(),
+        })
+    }
+
+    #[inline]
+    fn record(&mut self, event: ProfilerEvent) {
+        let thread_id = std::thread::current().id();
+        let events = self.events.entry(thread_id).or_default();
+
+        events.push(event);
+    }
+
+    fn calculate_thread_results(events: &Vec<ProfilerEvent>) -> CalculatedResults {
+        use self::ProfilerEvent::*;
+
+        assert!(
+            events.last().map(|e| !e.is_start_event()).unwrap_or(true),
+            "there was an event running when calculate_reslts() was called"
+        );
+
+        let mut results = CalculatedResults::new();
+
+        //(event, child time to subtract)
+        let mut query_stack = Vec::new();
+
+        for event in events {
+            match event {
+                QueryStart { .. } | GenericActivityStart { .. } => {
+                    query_stack.push((event, 0));
+                },
+                QueryEnd { query_name, category, time: end_time } => {
+                    let previous_query = query_stack.pop();
+                    if let Some((QueryStart {
+                                    query_name: p_query_name,
+                                    time: start_time,
+                                    category: _ }, child_time_to_subtract)) = previous_query {
+                        assert_eq!(
+                            p_query_name,
+                            query_name,
+                            "Saw a query end but the previous query wasn't the corresponding start"
+                        );
+
+                        let time_ns = time_between_ns(*start_time, *end_time);
+                        let self_time_ns = time_ns - child_time_to_subtract;
+                        let result_data = results.categories.entry(*category).or_default();
+
+                        *result_data.query_times.entry(query_name).or_default() += self_time_ns;
+
+                        if let Some((_, child_time_to_subtract)) = query_stack.last_mut() {
+                            *child_time_to_subtract += time_ns;
+                        }
+                    } else {
+                        bug!("Saw a query end but the previous event wasn't a query start");
+                    }
+                }
+                GenericActivityEnd { category, time: end_time } => {
+                    let previous_event = query_stack.pop();
+                    if let Some((GenericActivityStart {
+                                    category: previous_category,
+                                    time: start_time }, child_time_to_subtract)) = previous_event {
+                        assert_eq!(
+                            previous_category,
+                            category,
+                            "Saw an end but the previous event wasn't the corresponding start"
+                        );
+
+                        let time_ns = time_between_ns(*start_time, *end_time);
+                        let self_time_ns = time_ns - child_time_to_subtract;
+                        let result_data = results.categories.entry(*category).or_default();
+
+                        *result_data.query_times
+                            .entry("{time spent not running queries}")
+                            .or_default() += self_time_ns;
+
+                        if let Some((_, child_time_to_subtract)) = query_stack.last_mut() {
+                            *child_time_to_subtract += time_ns;
+                        }
+                    } else {
+                        bug!("Saw an activity end but the previous event wasn't an activity start");
+                    }
+                },
+                QueryCacheHit { category, query_name } => {
+                    let result_data = results.categories.entry(*category).or_default();
+
+                    let (hits, total) =
+                        result_data.query_cache_stats.entry(query_name).or_insert((0, 0));
+                    *hits += 1;
+                    *total += 1;
+                },
+                QueryCount { category, query_name, count } => {
+                    let result_data = results.categories.entry(*category).or_default();
+
+                    let (_, totals) =
+                        result_data.query_cache_stats.entry(query_name).or_insert((0, 0));
+                    *totals += *count as u64;
+                },
+                //we don't summarize incremental load result events in the simple output mode
+                IncrementalLoadResultStart { .. } | IncrementalLoadResultEnd { .. } => { },
+                //we don't summarize parallel query blocking in the simple output mode
+                QueryBlockedStart { .. } | QueryBlockedEnd { .. } => { },
+            }
         }
 
-        //check if the new running timer is in the same category as this one
-        //if it is, we don't need to do anything
-        if let Some(c) = self.timer_stack.last() {
-            if *c == category {
-                return;
+        //normalize the times to ms
+        for (_, data) in &mut results.categories {
+            for (_, time) in &mut data.query_times {
+                *time = *time / 1_000_000;
             }
         }
 
-        //the new timer is different than the previous,
-        //so record the elapsed time and start a new timer
-        let elapsed = self.stop_timer();
-        let new_time = self.data.times.get(category) + elapsed;
-        self.data.times.set(category, new_time);
+        results
     }
 
-    fn stop_timer(&mut self) -> u64 {
-        let elapsed = self.current_timer.elapsed();
-
-        self.current_timer = Instant::now();
-
-        (elapsed.as_secs() * 1_000_000_000) + (elapsed.subsec_nanos() as u64)
+    fn get_results(&self, opts: &Options) -> CalculatedResults {
+        self.events
+            .iter()
+            .map(|(_, r)| SelfProfiler::calculate_thread_results(r))
+            .fold(CalculatedResults::new(), CalculatedResults::consolidate)
+            .with_options(opts)
     }
 
     pub fn print_results(&mut self, opts: &Options) {
         self.end_activity(ProfileCategory::Other);
 
-        assert!(
-            self.timer_stack.is_empty(),
-            "there were timers running when print_results() was called");
+        let results = self.get_results(opts);
+
+        let total_time = results.total_time() as f32;
 
         let out = io::stderr();
         let mut lock = out.lock();
 
-        let crate_name =
-            opts.crate_name
-            .as_ref()
-            .map(|n| format!(" for {}", n))
-            .unwrap_or_default();
+        let crate_name = results.crate_name.map(|n| format!(" for {}", n)).unwrap_or_default();
 
         writeln!(lock, "Self profiling results{}:", crate_name).unwrap();
         writeln!(lock).unwrap();
 
-        self.data.print(&mut lock);
+        writeln!(lock, "| Phase                                     | Time (ms)      \
+                        | Time (%) | Queries        | Hits (%)")
+            .unwrap();
+        writeln!(lock, "| ----------------------------------------- | -------------- \
+                        | -------- | -------------- | --------")
+            .unwrap();
+
+        let mut categories: Vec<_> = results.categories.iter().collect();
+        categories.sort_by_cached_key(|(_, d)| d.total_time());
+
+        for (category, data) in categories.iter().rev() {
+            let (category_hits, category_total) = data.total_cache_data();
+            let category_hit_percent = calculate_percent(category_hits, category_total);
+
+            writeln!(
+                lock,
+                "| {0: <41} | {1: >14} | {2: >8.2} | {3: >14} | {4: >8}",
+                format!("{:?}", category),
+                data.total_time(),
+                ((data.total_time() as f32) / total_time) * 100.0,
+                category_total,
+                format!("{:.2}", category_hit_percent),
+            ).unwrap();
+
+            //in verbose mode, show individual query data
+            if results.verbose {
+                //don't show queries that took less than 1ms
+                let mut times: Vec<_> = data.query_times.iter().filter(|(_, t)| **t > 0).collect();
+                times.sort_by(|(_, time1), (_, time2)| time2.cmp(time1));
+
+                for (query, time) in times {
+                    let (hits, total) = data.query_cache_stats.get(query).unwrap_or(&(0, 0));
+                    let hit_percent = calculate_percent(*hits, *total);
+
+                    writeln!(
+                        lock,
+                        "| - {0: <39} | {1: >14} | {2: >8.2} | {3: >14} | {4: >8}",
+                        query,
+                        time,
+                        ((*time as f32) / total_time) * 100.0,
+                        total,
+                        format!("{:.2}", hit_percent),
+                    ).unwrap();
+                }
+            }
+        }
 
         writeln!(lock).unwrap();
         writeln!(lock, "Optimization level: {:?}", opts.optimize).unwrap();
-
-        let incremental = if opts.incremental.is_some() { "on" } else { "off" };
-        writeln!(lock, "Incremental: {}", incremental).unwrap();
+        writeln!(lock, "Incremental: {}", if results.incremental { "on" } else { "off" }).unwrap();
     }
 
     pub fn save_results(&self, opts: &Options) {
-        let category_data = self.data.json();
+        let results = self.get_results(opts);
+
         let compilation_options =
             format!("{{ \"optimization_level\": \"{:?}\", \"incremental\": {} }}",
-                    opts.optimize,
-                    if opts.incremental.is_some() { "true" } else { "false" });
+                    results.optimization_level,
+                    if results.incremental { "true" } else { "false" });
+
+        let mut category_data = String::new();
+
+        for (category, data) in &results.categories {
+            let (hits, total) = data.total_cache_data();
+            let hit_percent = calculate_percent(hits, total);
+
+            category_data.push_str(&format!("{{ \"category\": \"{:?}\", \"time_ms\": {}, \
+                                                \"query_count\": {}, \"query_hits\": {} }}",
+                                            category,
+                                            data.total_time(),
+                                            total,
+                                            format!("{:.2}", hit_percent)));
+        }
 
         let json = format!("{{ \"category_data\": {}, \"compilation_options\": {} }}",
                         category_data,
diff --git a/src/librustc_allocator/Cargo.toml b/src/librustc_allocator/Cargo.toml
index 03d33f413c807..cf6c598bfb17b 100644
--- a/src/librustc_allocator/Cargo.toml
+++ b/src/librustc_allocator/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_allocator"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 path = "lib.rs"
diff --git a/src/librustc_allocator/expand.rs b/src/librustc_allocator/expand.rs
index 73a35c7cdcd5f..758a0d63886b1 100644
--- a/src/librustc_allocator/expand.rs
+++ b/src/librustc_allocator/expand.rs
@@ -1,6 +1,6 @@
+use log::debug;
 use rustc::middle::allocator::AllocatorKind;
-use rustc_errors;
-use smallvec::SmallVec;
+use smallvec::{smallvec, SmallVec};
 use syntax::{
     ast::{
         self, Arg, Attribute, Crate, Expr, FnHeader, Generics, Ident, Item, ItemKind,
@@ -16,22 +16,22 @@ use syntax::{
         expand::ExpansionConfig,
         hygiene::{self, Mark, SyntaxContext},
     },
-    fold::{self, Folder},
+    mut_visit::{self, MutVisitor},
     parse::ParseSess,
     ptr::P,
     symbol::Symbol
 };
 use syntax_pos::Span;
 
-use {AllocatorMethod, AllocatorTy, ALLOCATOR_METHODS};
+use crate::{AllocatorMethod, AllocatorTy, ALLOCATOR_METHODS};
 
 pub fn modify(
     sess: &ParseSess,
     resolver: &mut dyn Resolver,
-    krate: Crate,
+    krate: &mut Crate,
     crate_name: String,
     handler: &rustc_errors::Handler,
-) -> ast::Crate {
+) {
     ExpandAllocatorDirectives {
         handler,
         sess,
@@ -39,7 +39,7 @@ pub fn modify(
         found: false,
         crate_name: Some(crate_name),
         in_submod: -1, // -1 to account for the "root" module
-    }.fold_crate(krate)
+    }.visit_crate(krate);
 }
 
 struct ExpandAllocatorDirectives<'a> {
@@ -54,14 +54,14 @@ struct ExpandAllocatorDirectives<'a> {
     in_submod: isize,
 }
 
-impl<'a> Folder for ExpandAllocatorDirectives<'a> {
-    fn fold_item(&mut self, item: P<Item>) -> SmallVec<[P<Item>; 1]> {
+impl MutVisitor for ExpandAllocatorDirectives<'_> {
+    fn flat_map_item(&mut self, item: P<Item>) -> SmallVec<[P<Item>; 1]> {
         debug!("in submodule {}", self.in_submod);
 
         let name = if attr::contains_name(&item.attrs, "global_allocator") {
             "global_allocator"
         } else {
-            return fold::noop_fold_item(item, self);
+            return mut_visit::noop_flat_map_item(item, self);
         };
         match item.node {
             ItemKind::Static(..) => {}
@@ -91,7 +91,9 @@ impl<'a> Folder for ExpandAllocatorDirectives<'a> {
             call_site: item.span, // use the call site of the static
             def_site: None,
             format: MacroAttribute(Symbol::intern(name)),
-            allow_internal_unstable: true,
+            allow_internal_unstable: Some(vec![
+                Symbol::intern("rustc_attrs"),
+            ].into()),
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: hygiene::default_edition(),
@@ -139,25 +141,24 @@ impl<'a> Folder for ExpandAllocatorDirectives<'a> {
         let name = f.kind.fn_name("allocator_abi");
         let allocator_abi = Ident::with_empty_ctxt(Symbol::gensym(&name));
         let module = f.cx.item_mod(span, span, allocator_abi, Vec::new(), items);
-        let module = f.cx.monotonic_expander().fold_item(module).pop().unwrap();
+        let module = f.cx.monotonic_expander().flat_map_item(module).pop().unwrap();
 
         // Return the item and new submodule
         smallvec![item, module]
     }
 
     // If we enter a submodule, take note.
-    fn fold_mod(&mut self, m: Mod) -> Mod {
+    fn visit_mod(&mut self, m: &mut Mod) {
         debug!("enter submodule");
         self.in_submod += 1;
-        let ret = fold::noop_fold_mod(m, self);
+        mut_visit::noop_visit_mod(m, self);
         self.in_submod -= 1;
         debug!("exit submodule");
-        ret
     }
 
-    // `fold_mac` is disabled by default. Enable it here.
-    fn fold_mac(&mut self, mac: Mac) -> Mac {
-        fold::noop_fold_mac(mac, self)
+    // `visit_mac` is disabled by default. Enable it here.
+    fn visit_mac(&mut self, mac: &mut Mac) {
+        mut_visit::noop_visit_mac(mac, self)
     }
 }
 
@@ -169,7 +170,7 @@ struct AllocFnFactory<'a> {
     cx: ExtCtxt<'a>,
 }
 
-impl<'a> AllocFnFactory<'a> {
+impl AllocFnFactory<'_> {
     fn allocator_fn(&self, method: &AllocatorMethod) -> P<Item> {
         let mut abi_args = Vec::new();
         let mut i = 0;
diff --git a/src/librustc_allocator/lib.rs b/src/librustc_allocator/lib.rs
index 41c0be615956e..9d6e728e13557 100644
--- a/src/librustc_allocator/lib.rs
+++ b/src/librustc_allocator/lib.rs
@@ -1,15 +1,7 @@
 #![feature(nll)]
 #![feature(rustc_private)]
 
-#[macro_use] extern crate log;
-extern crate rustc;
-extern crate rustc_data_structures;
-extern crate rustc_errors;
-extern crate rustc_target;
-extern crate syntax;
-extern crate syntax_pos;
-#[macro_use]
-extern crate smallvec;
+#![deny(rust_2018_idioms)]
 
 pub mod expand;
 
diff --git a/src/librustc_apfloat/Cargo.toml b/src/librustc_apfloat/Cargo.toml
index 248f2d71f41e5..c7496a9547ea6 100644
--- a/src/librustc_apfloat/Cargo.toml
+++ b/src/librustc_apfloat/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_apfloat"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_apfloat"
diff --git a/src/librustc_apfloat/ieee.rs b/src/librustc_apfloat/ieee.rs
index 7ad34bec899f4..9f68d770b9e87 100644
--- a/src/librustc_apfloat/ieee.rs
+++ b/src/librustc_apfloat/ieee.rs
@@ -1,5 +1,5 @@
-use {Category, ExpInt, IEK_INF, IEK_NAN, IEK_ZERO};
-use {Float, FloatConvert, ParseError, Round, Status, StatusAnd};
+use crate::{Category, ExpInt, IEK_INF, IEK_NAN, IEK_ZERO};
+use crate::{Float, FloatConvert, ParseError, Round, Status, StatusAnd};
 
 use smallvec::{SmallVec, smallvec};
 use std::cmp::{self, Ordering};
@@ -186,7 +186,7 @@ impl Semantics for X87DoubleExtendedS {
     ///  exponent = all 1's, integer bit 0, significand 0 ("pseudoinfinity")
     ///  exponent = all 1's, integer bit 0, significand nonzero ("pseudoNaN")
     ///  exponent = 0, integer bit 1 ("pseudodenormal")
-    ///  exponent!=0 nor all 1's, integer bit 0 ("unnormal")
+    ///  exponent != 0 nor all 1's, integer bit 0 ("unnormal")
     /// At the moment, the first two are treated as NaNs, the second two as Normal.
     fn from_bits(bits: u128) -> IeeeFloat<Self> {
         let sign = bits & (1 << (Self::BITS - 1));
@@ -325,7 +325,7 @@ impl<S> Neg for IeeeFloat<S> {
 /// 1.01E-2              4        2       0.0101
 /// 1.01E-2              4        1       1.01E-2
 impl<S: Semantics> fmt::Display for IeeeFloat<S> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let width = f.width().unwrap_or(3);
         let alternate = f.alternate();
 
@@ -614,7 +614,7 @@ impl<S: Semantics> fmt::Display for IeeeFloat<S> {
 }
 
 impl<S: Semantics> fmt::Debug for IeeeFloat<S> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}({:?} | {}{:?} * 2^{})",
                self, self.category,
                if self.sign { "-" } else { "+" },
@@ -1549,11 +1549,11 @@ impl<S: Semantics> IeeeFloat<S> {
         }
     }
 
-    /// Returns TRUE if, when truncating the current number, with BIT the
+    /// Returns `true` if, when truncating the current number, with `bit` the
     /// new LSB, with the given lost fraction and rounding mode, the result
     /// would need to be rounded away from zero (i.e., by increasing the
-    /// signficand). This routine must work for Category::Zero of both signs, and
-    /// Category::Normal numbers.
+    /// signficand). This routine must work for `Category::Zero` of both signs, and
+    /// `Category::Normal` numbers.
     fn round_away_from_zero(&self, round: Round, loss: Loss, bit: usize) -> bool {
         // NaNs and infinities should not have lost fractions.
         assert!(self.is_finite_non_zero() || self.is_zero());
@@ -2257,7 +2257,7 @@ impl Loss {
         more_significant
     }
 
-    /// Return the fraction lost were a bignum truncated losing the least
+    /// Returns the fraction lost were a bignum truncated losing the least
     /// significant `bits` bits.
     fn through_truncation(limbs: &[Limb], bits: usize) -> Loss {
         if bits == 0 {
@@ -2320,12 +2320,12 @@ mod sig {
         Ordering::Equal
     }
 
-    /// Extract the given bit.
+    /// Extracts the given bit.
     pub(super) fn get_bit(limbs: &[Limb], bit: usize) -> bool {
         limbs[bit / LIMB_BITS] & (1 << (bit % LIMB_BITS)) != 0
     }
 
-    /// Set the given bit.
+    /// Sets the given bit.
     pub(super) fn set_bit(limbs: &mut [Limb], bit: usize) {
         limbs[bit / LIMB_BITS] |= 1 << (bit % LIMB_BITS);
     }
@@ -2335,7 +2335,7 @@ mod sig {
         limbs[bit / LIMB_BITS] &= !(1 << (bit % LIMB_BITS));
     }
 
-    /// Shift `dst` left `bits` bits, subtract `bits` from its exponent.
+    /// Shifts `dst` left `bits` bits, subtract `bits` from its exponent.
     pub(super) fn shift_left(dst: &mut [Limb], exp: &mut ExpInt, bits: usize) {
         if bits > 0 {
             // Our exponent should not underflow.
@@ -2367,7 +2367,7 @@ mod sig {
         }
     }
 
-    /// Shift `dst` right `bits` bits noting lost fraction.
+    /// Shifts `dst` right `bits` bits noting lost fraction.
     pub(super) fn shift_right(dst: &mut [Limb], exp: &mut ExpInt, bits: usize) -> Loss {
         let loss = Loss::through_truncation(dst, bits);
 
@@ -2403,7 +2403,7 @@ mod sig {
         loss
     }
 
-    /// Copy the bit vector of width `src_bits` from `src`, starting at bit SRC_LSB,
+    /// Copies the bit vector of width `src_bits` from `src`, starting at bit SRC_LSB,
     /// to `dst`, such that the bit SRC_LSB becomes the least significant bit of `dst`.
     /// All high bits above `src_bits` in `dst` are zero-filled.
     pub(super) fn extract(dst: &mut [Limb], src: &[Limb], src_bits: usize, src_lsb: usize) {
diff --git a/src/librustc_apfloat/lib.rs b/src/librustc_apfloat/lib.rs
index 6d2c54ca9ffe9..46d046d7b41b4 100644
--- a/src/librustc_apfloat/lib.rs
+++ b/src/librustc_apfloat/lib.rs
@@ -30,10 +30,9 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![forbid(unsafe_code)]
+#![deny(rust_2018_idioms)]
 
 #![feature(nll)]
 #![feature(try_from)]
@@ -41,17 +40,13 @@
 #[allow(unused_extern_crates)]
 extern crate rustc_cratesio_shim;
 
-#[macro_use]
-extern crate bitflags;
-extern crate smallvec;
-
 use std::cmp::Ordering;
 use std::fmt;
 use std::ops::{Neg, Add, Sub, Mul, Div, Rem};
 use std::ops::{AddAssign, SubAssign, MulAssign, DivAssign, RemAssign};
 use std::str::FromStr;
 
-bitflags! {
+bitflags::bitflags! {
     /// IEEE-754R 7: Default exception handling.
     ///
     /// UNDERFLOW or OVERFLOW are always returned or-ed with INEXACT.
@@ -380,7 +375,7 @@ pub trait Float
     fn from_str_r(s: &str, round: Round) -> Result<StatusAnd<Self>, ParseError>;
     fn to_bits(self) -> u128;
 
-    /// Convert a floating point number to an integer according to the
+    /// Converts a floating point number to an integer according to the
     /// rounding mode. In case of an invalid operation exception,
     /// deterministic values are returned, namely zero for NaNs and the
     /// minimal or maximal value respectively for underflow or overflow.
@@ -393,7 +388,7 @@ pub trait Float
     ///
     /// The *is_exact output tells whether the result is exact, in the sense
     /// that converting it back to the original floating point type produces
-    /// the original value. This is almost equivalent to result==Status::OK,
+    /// the original value. This is almost equivalent to `result == Status::OK`,
     /// except for negative zeroes.
     fn to_i128_r(self, width: usize, round: Round, is_exact: &mut bool) -> StatusAnd<i128> {
         let status;
@@ -463,13 +458,13 @@ pub trait Float
         }
     }
 
-    /// IEEE-754R isSignMinus: Returns true if and only if the current value is
+    /// IEEE-754R isSignMinus: Returns whether the current value is
     /// negative.
     ///
     /// This applies to zeros and NaNs as well.
     fn is_negative(self) -> bool;
 
-    /// IEEE-754R isNormal: Returns true if and only if the current value is normal.
+    /// IEEE-754R isNormal: Returns whether the current value is normal.
     ///
     /// This implies that the current value of the float is not zero, subnormal,
     /// infinite, or NaN following the definition of normality from IEEE-754R.
@@ -477,7 +472,7 @@ pub trait Float
         !self.is_denormal() && self.is_finite_non_zero()
     }
 
-    /// Returns true if and only if the current value is zero, subnormal, or
+    /// Returns `true` if the current value is zero, subnormal, or
     /// normal.
     ///
     /// This means that the value is not infinite or NaN.
@@ -485,26 +480,26 @@ pub trait Float
         !self.is_nan() && !self.is_infinite()
     }
 
-    /// Returns true if and only if the float is plus or minus zero.
+    /// Returns `true` if the float is plus or minus zero.
     fn is_zero(self) -> bool {
         self.category() == Category::Zero
     }
 
-    /// IEEE-754R isSubnormal(): Returns true if and only if the float is a
+    /// IEEE-754R isSubnormal(): Returns whether the float is a
     /// denormal.
     fn is_denormal(self) -> bool;
 
-    /// IEEE-754R isInfinite(): Returns true if and only if the float is infinity.
+    /// IEEE-754R isInfinite(): Returns whether the float is infinity.
     fn is_infinite(self) -> bool {
         self.category() == Category::Infinity
     }
 
-    /// Returns true if and only if the float is a quiet or signaling NaN.
+    /// Returns `true` if the float is a quiet or signaling NaN.
     fn is_nan(self) -> bool {
         self.category() == Category::NaN
     }
 
-    /// Returns true if and only if the float is a signaling NaN.
+    /// Returns `true` if the float is a signaling NaN.
     fn is_signaling(self) -> bool;
 
     // Simple Queries
@@ -523,19 +518,19 @@ pub trait Float
         self.is_zero() && self.is_negative()
     }
 
-    /// Returns true if and only if the number has the smallest possible non-zero
+    /// Returns `true` if the number has the smallest possible non-zero
     /// magnitude in the current semantics.
     fn is_smallest(self) -> bool {
         Self::SMALLEST.copy_sign(self).bitwise_eq(self)
     }
 
-    /// Returns true if and only if the number has the largest possible finite
+    /// Returns `true` if the number has the largest possible finite
     /// magnitude in the current semantics.
     fn is_largest(self) -> bool {
         Self::largest().copy_sign(self).bitwise_eq(self)
     }
 
-    /// Returns true if and only if the number is an exact integer.
+    /// Returns `true` if the number is an exact integer.
     fn is_integer(self) -> bool {
         // This could be made more efficient; I'm going for obviously correct.
         if !self.is_finite() {
@@ -577,11 +572,11 @@ pub trait Float
 }
 
 pub trait FloatConvert<T: Float>: Float {
-    /// Convert a value of one floating point type to another.
+    /// Converts a value of one floating point type to another.
     /// The return value corresponds to the IEEE754 exceptions. *loses_info
     /// records whether the transformation lost information, i.e., whether
     /// converting the result back to the original type will produce the
-    /// original value (this is almost the same as return value==Status::OK,
+    /// original value (this is almost the same as return `value == Status::OK`,
     /// but there are edge cases where this is not so).
     fn convert_r(self, round: Round, loses_info: &mut bool) -> StatusAnd<T>;
     fn convert(self, loses_info: &mut bool) -> StatusAnd<T> {
diff --git a/src/librustc_apfloat/ppc.rs b/src/librustc_apfloat/ppc.rs
index 839e88cf34039..ddccfd6ca623b 100644
--- a/src/librustc_apfloat/ppc.rs
+++ b/src/librustc_apfloat/ppc.rs
@@ -1,5 +1,5 @@
-use {Category, ExpInt, Float, FloatConvert, Round, ParseError, Status, StatusAnd};
-use ieee;
+use crate::{Category, ExpInt, Float, FloatConvert, Round, ParseError, Status, StatusAnd};
+use crate::ieee;
 
 use std::cmp::Ordering;
 use std::fmt;
@@ -124,7 +124,7 @@ impl<F: Float> Neg for DoubleFloat<F> {
 }
 
 impl<F: FloatConvert<Fallback<F>>> fmt::Display for DoubleFloat<F> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&Fallback::from(*self), f)
     }
 }
diff --git a/src/librustc_apfloat/tests/ieee.rs b/src/librustc_apfloat/tests/ieee.rs
index 96249020c1a6f..108b2114439d4 100644
--- a/src/librustc_apfloat/tests/ieee.rs
+++ b/src/librustc_apfloat/tests/ieee.rs
@@ -1,9 +1,7 @@
-#[macro_use]
-extern crate rustc_apfloat;
-
 use rustc_apfloat::{Category, ExpInt, IEK_INF, IEK_NAN, IEK_ZERO};
 use rustc_apfloat::{Float, FloatConvert, ParseError, Round, Status};
 use rustc_apfloat::ieee::{Half, Single, Double, Quad, X87DoubleExtended};
+use rustc_apfloat::unpack;
 
 trait SingleExt {
     fn from_f32(input: f32) -> Self;
diff --git a/src/librustc_apfloat/tests/ppc.rs b/src/librustc_apfloat/tests/ppc.rs
index cfb453bd0617a..02cdeb90a12be 100644
--- a/src/librustc_apfloat/tests/ppc.rs
+++ b/src/librustc_apfloat/tests/ppc.rs
@@ -1,5 +1,3 @@
-extern crate rustc_apfloat;
-
 use rustc_apfloat::{Category, Float, Round};
 use rustc_apfloat::ppc::DoubleDouble;
 
diff --git a/src/librustc_asan/Cargo.toml b/src/librustc_asan/Cargo.toml
index 836caf22abfa5..7d9641c83ee7d 100644
--- a/src/librustc_asan/Cargo.toml
+++ b/src/librustc_asan/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 build = "build.rs"
 name = "rustc_asan"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_asan"
diff --git a/src/librustc_asan/build.rs b/src/librustc_asan/build.rs
index 2d921b666944b..a2b4b090efb4f 100644
--- a/src/librustc_asan/build.rs
+++ b/src/librustc_asan/build.rs
@@ -1,6 +1,3 @@
-extern crate build_helper;
-extern crate cmake;
-
 use std::env;
 use build_helper::sanitizer_lib_boilerplate;
 
@@ -8,6 +5,8 @@ use cmake::Config;
 
 fn main() {
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
+        build_helper::restore_library_path();
+
         let (native, target) = match sanitizer_lib_boilerplate("asan") {
             Ok(native) => native,
             _ => return,
diff --git a/src/librustc_asan/lib.rs b/src/librustc_asan/lib.rs
index d6c8e54c18db7..3bdb86d313dcb 100644
--- a/src/librustc_asan/lib.rs
+++ b/src/librustc_asan/lib.rs
@@ -6,3 +6,5 @@
 #![unstable(feature = "sanitizer_runtime_lib",
             reason = "internal implementation detail of sanitizers",
             issue = "0")]
+
+#![deny(rust_2018_idioms)]
diff --git a/src/librustc_borrowck/Cargo.toml b/src/librustc_borrowck/Cargo.toml
index 3368bbf3855a5..f293739dec727 100644
--- a/src/librustc_borrowck/Cargo.toml
+++ b/src/librustc_borrowck/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_borrowck"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_borrowck"
@@ -13,8 +14,10 @@ test = false
 log = "0.4"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-graphviz = { path = "../libgraphviz" }
+# for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
+# refers to the borrowck-specific graphviz adapter traits.
+dot = { path = "../libgraphviz", package = "graphviz" }
 rustc = { path = "../librustc" }
 rustc_mir = { path = "../librustc_mir" }
-rustc_errors = { path = "../librustc_errors" }
-rustc_data_structures = { path = "../librustc_data_structures" }
\ No newline at end of file
+errors = { path = "../librustc_errors", package = "rustc_errors" }
+rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/librustc_borrowck/borrowck/check_loans.rs b/src/librustc_borrowck/borrowck/check_loans.rs
index cafb29ed99a41..b528967dd65ff 100644
--- a/src/librustc_borrowck/borrowck/check_loans.rs
+++ b/src/librustc_borrowck/borrowck/check_loans.rs
@@ -7,10 +7,10 @@
 // 3. assignments do not affect things loaned out as immutable
 // 4. moves do not affect things loaned out in any way
 
-use self::UseError::*;
+use UseError::*;
 
-use borrowck::*;
-use borrowck::InteriorKind::{InteriorElement, InteriorField};
+use crate::borrowck::*;
+use crate::borrowck::InteriorKind::{InteriorElement, InteriorField};
 use rustc::middle::expr_use_visitor as euv;
 use rustc::middle::expr_use_visitor::MutateMode;
 use rustc::middle::mem_categorization as mc;
@@ -22,6 +22,7 @@ use syntax_pos::Span;
 use rustc::hir;
 use rustc::hir::Node;
 use rustc_mir::util::borrowck_errors::{BorrowckErrors, Origin};
+use log::debug;
 
 use std::rc::Rc;
 
@@ -101,7 +102,7 @@ impl<'a, 'tcx> euv::Delegate<'tcx> for CheckLoanCtxt<'a, 'tcx> {
 
     fn matched_pat(&mut self,
                    _matched_pat: &hir::Pat,
-                   _cmt: &mc::cmt_,
+                   _cmt: &mc::cmt_<'_>,
                    _mode: euv::MatchMode) { }
 
     fn consume_pat(&mut self,
@@ -238,7 +239,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
     {
         //! Iterates over each loan that has been issued
         //! on entrance to `node`, regardless of whether it is
-        //! actually *in scope* at that point.  Sometimes loans
+        //! actually *in scope* at that point. Sometimes loans
         //! are issued for future scopes and thus they may have been
         //! *issued* but not yet be in effect.
 
@@ -910,7 +911,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
     pub fn report_illegal_mutation(&self,
                                    span: Span,
                                    loan_path: &LoanPath<'tcx>,
-                                   loan: &Loan) {
+                                   loan: &Loan<'_>) {
         self.bccx.cannot_assign_to_borrowed(
             span, loan.span, &self.bccx.loan_path_to_string(loan_path), Origin::Ast)
             .emit();
diff --git a/src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs b/src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs
index 72437e270b092..6b050fd9ba230 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs
@@ -1,9 +1,9 @@
 //! Computes moves.
 
-use borrowck::*;
-use borrowck::gather_loans::move_error::MovePlace;
-use borrowck::gather_loans::move_error::{MoveError, MoveErrorCollector};
-use borrowck::move_data::*;
+use crate::borrowck::*;
+use crate::borrowck::gather_loans::move_error::MovePlace;
+use crate::borrowck::gather_loans::move_error::{MoveError, MoveErrorCollector};
+use crate::borrowck::move_data::*;
 use rustc::middle::expr_use_visitor as euv;
 use rustc::middle::mem_categorization as mc;
 use rustc::middle::mem_categorization::Categorization;
@@ -15,6 +15,7 @@ use syntax::ast;
 use syntax_pos::Span;
 use rustc::hir::*;
 use rustc::hir::Node;
+use log::debug;
 
 struct GatherMoveInfo<'c, 'tcx: 'c> {
     id: hir::ItemLocalId,
@@ -99,7 +100,7 @@ pub fn gather_move_from_pat<'a, 'c, 'tcx: 'c>(bccx: &BorrowckCtxt<'a, 'tcx>,
                                               cmt: &'c mc::cmt_<'tcx>) {
     let source = get_pattern_source(bccx.tcx,move_pat);
     let pat_span_path_opt = match move_pat.node {
-        PatKind::Binding(_, _, ident, _) => {
+        PatKind::Binding(_, _, _, ident, _) => {
             Some(MovePlace {
                      span: move_pat.span,
                      name: ident.name,
diff --git a/src/librustc_borrowck/borrowck/gather_loans/lifetime.rs b/src/librustc_borrowck/borrowck/gather_loans/lifetime.rs
index 8fc0a3d63384a..ae1d49afd4931 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/lifetime.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/lifetime.rs
@@ -1,7 +1,7 @@
 //! This module implements the check that the lifetime of a borrow
 //! does not exceed the lifetime of the value being borrowed.
 
-use borrowck::*;
+use crate::borrowck::*;
 use rustc::middle::expr_use_visitor as euv;
 use rustc::middle::mem_categorization as mc;
 use rustc::middle::mem_categorization::Categorization;
@@ -10,6 +10,7 @@ use rustc::ty;
 
 use syntax::ast;
 use syntax_pos::Span;
+use log::debug;
 
 type R = Result<(),()>;
 
@@ -52,7 +53,7 @@ struct GuaranteeLifetimeContext<'a, 'tcx: 'a> {
 impl<'a, 'tcx> GuaranteeLifetimeContext<'a, 'tcx> {
     fn check(&self, cmt: &mc::cmt_<'tcx>, discr_scope: Option<ast::NodeId>) -> R {
         //! Main routine. Walks down `cmt` until we find the
-        //! "guarantor".  Reports an error if `self.loan_region` is
+        //! "guarantor". Reports an error if `self.loan_region` is
         //! larger than scope of `cmt`.
         debug!("guarantee_lifetime.check(cmt={:?}, loan_region={:?})",
                cmt,
diff --git a/src/librustc_borrowck/borrowck/gather_loans/mod.rs b/src/librustc_borrowck/borrowck/gather_loans/mod.rs
index d681c771d2fa9..cf6053b71b6a8 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/mod.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/mod.rs
@@ -6,8 +6,8 @@
 // their associated scopes.  In phase two, checking loans, we will then make
 // sure that all of these loans are honored.
 
-use borrowck::*;
-use borrowck::move_data::MoveData;
+use crate::borrowck::*;
+use crate::borrowck::move_data::MoveData;
 use rustc::middle::expr_use_visitor as euv;
 use rustc::middle::mem_categorization as mc;
 use rustc::middle::mem_categorization::Categorization;
@@ -17,8 +17,9 @@ use rustc::ty::{self, TyCtxt};
 use syntax::ast;
 use syntax_pos::Span;
 use rustc::hir;
+use log::debug;
 
-use self::restrictions::RestrictionResult;
+use restrictions::RestrictionResult;
 
 mod lifetime;
 mod restrictions;
@@ -148,7 +149,7 @@ impl<'a, 'tcx> euv::Delegate<'tcx> for GatherLoanCtxt<'a, 'tcx> {
     fn decl_without_init(&mut self, id: ast::NodeId, _span: Span) {
         let ty = self.bccx
                      .tables
-                     .node_id_to_type(self.bccx.tcx.hir().node_to_hir_id(id));
+                     .node_type(self.bccx.tcx.hir().node_to_hir_id(id));
         gather_moves::gather_decl(self.bccx, &self.move_data, id, ty);
     }
 }
@@ -284,7 +285,7 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
     }
 
     /// Guarantees that `addr_of(cmt)` will be valid for the duration of `static_scope_r`, or
-    /// reports an error.  This may entail taking out loans, which will be added to the
+    /// reports an error. This may entail taking out loans, which will be added to the
     /// `req_loan_map`.
     fn guarantee_valid(&mut self,
                        borrow_id: hir::ItemLocalId,
@@ -427,7 +428,7 @@ impl<'a, 'tcx> GatherLoanCtxt<'a, 'tcx> {
         // }
     }
 
-    pub fn mark_loan_path_as_mutated(&self, loan_path: &LoanPath) {
+    pub fn mark_loan_path_as_mutated(&self, loan_path: &LoanPath<'_>) {
         //! For mutable loans of content whose mutability derives
         //! from a local variable, mark the mutability decl as necessary.
 
diff --git a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
index 588b2344a18e0..622dd8e891ac7 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
@@ -1,4 +1,4 @@
-use borrowck::BorrowckCtxt;
+use crate::borrowck::BorrowckCtxt;
 use rustc::middle::mem_categorization as mc;
 use rustc::middle::mem_categorization::Categorization;
 use rustc::middle::mem_categorization::NoteClosureEnv;
@@ -8,7 +8,8 @@ use rustc_mir::util::borrowck_errors::{BorrowckErrors, Origin};
 use syntax::ast;
 use syntax_pos;
 use errors::{DiagnosticBuilder, Applicability};
-use borrowck::gather_loans::gather_moves::PatternSource;
+use crate::borrowck::gather_loans::gather_moves::PatternSource;
+use log::debug;
 
 pub struct MoveErrorCollector<'tcx> {
     errors: Vec<MoveError<'tcx>>
@@ -70,7 +71,7 @@ fn report_move_errors<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>, errors: &[MoveErr
                 let initializer =
                     e.init.as_ref().expect("should have an initializer to get an error");
                 if let Ok(snippet) = bccx.tcx.sess.source_map().span_to_snippet(initializer.span) {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         initializer.span,
                         "consider using a reference instead",
                         format!("&{}", snippet),
@@ -167,10 +168,10 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &'a BorrowckCtxt<'a, 'tcx>,
     }
 }
 
-fn note_move_destination(mut err: DiagnosticBuilder,
+fn note_move_destination(mut err: DiagnosticBuilder<'_>,
                          move_to_span: syntax_pos::Span,
                          pat_name: ast::Name,
-                         is_first_note: bool) -> DiagnosticBuilder {
+                         is_first_note: bool) -> DiagnosticBuilder<'_> {
     if is_first_note {
         err.span_label(
             move_to_span,
diff --git a/src/librustc_borrowck/borrowck/gather_loans/restrictions.rs b/src/librustc_borrowck/borrowck/gather_loans/restrictions.rs
index a43a7f1e09ae1..9f4c05a6b255f 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/restrictions.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/restrictions.rs
@@ -1,13 +1,14 @@
 //! Computes the restrictions that result from a borrow.
 
-use borrowck::*;
+use crate::borrowck::*;
 use rustc::middle::expr_use_visitor as euv;
 use rustc::middle::mem_categorization as mc;
 use rustc::middle::mem_categorization::Categorization;
 use rustc::ty;
 use syntax_pos::Span;
+use log::debug;
 
-use borrowck::ToInteriorKind;
+use crate::borrowck::ToInteriorKind;
 
 use std::rc::Rc;
 
diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs
index 66303ab71b25f..307df16386639 100644
--- a/src/librustc_borrowck/borrowck/mod.rs
+++ b/src/librustc_borrowck/borrowck/mod.rs
@@ -2,13 +2,13 @@
 
 #![allow(non_camel_case_types)]
 
-pub use self::LoanPathKind::*;
-pub use self::LoanPathElem::*;
-pub use self::bckerr_code::*;
-pub use self::AliasableViolationKind::*;
-pub use self::MovedValueUseKind::*;
+pub use LoanPathKind::*;
+pub use LoanPathElem::*;
+pub use bckerr_code::*;
+pub use AliasableViolationKind::*;
+pub use MovedValueUseKind::*;
 
-use self::InteriorKind::*;
+use InteriorKind::*;
 
 use rustc::hir::HirId;
 use rustc::hir::Node;
@@ -37,11 +37,11 @@ use std::hash::{Hash, Hasher};
 use syntax::ast;
 use syntax_pos::{MultiSpan, Span};
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use log::debug;
 
 use rustc::hir;
-use rustc::hir::intravisit::{self, Visitor};
 
-use dataflow::{DataFlowContext, BitwiseOperator, DataFlowOperator, KillFrom};
+use crate::dataflow::{DataFlowContext, BitwiseOperator, DataFlowOperator, KillFrom};
 
 pub mod check_loans;
 
@@ -58,11 +58,11 @@ pub type LoanDataFlow<'a, 'tcx> = DataFlowContext<'a, 'tcx, LoanDataFlowOperator
 
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     tcx.par_body_owners(|body_owner_def_id| {
-        tcx.borrowck(body_owner_def_id);
+        tcx.ensure().borrowck(body_owner_def_id);
     });
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         borrowck,
         ..*providers
@@ -122,7 +122,7 @@ fn borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, owner_def_id: DefId)
     // Note that `mir_validated` is a "stealable" result; the
     // thief, `optimized_mir()`, forces borrowck, so we know that
     // is not yet stolen.
-    ty::query::queries::mir_validated::ensure(tcx, owner_def_id);
+    tcx.ensure().mir_validated(owner_def_id);
 
     // option dance because you can't capture an uninitialized variable
     // by mut-ref.
@@ -157,12 +157,6 @@ fn build_borrowck_dataflow_data<'a, 'c, 'tcx, F>(this: &mut BorrowckCtxt<'a, 'tc
     where F: FnOnce(&mut BorrowckCtxt<'a, 'tcx>) -> &'c cfg::CFG
 {
     // Check the body of fn items.
-    let tcx = this.tcx;
-    let id_range = {
-        let mut visitor = intravisit::IdRangeComputingVisitor::new(&tcx.hir());
-        visitor.visit_body(this.body);
-        visitor.result()
-    };
     let (all_loans, move_data) =
         gather_loans::gather_loans_in_fn(this, body_id);
 
@@ -184,7 +178,6 @@ fn build_borrowck_dataflow_data<'a, 'c, 'tcx, F>(this: &mut BorrowckCtxt<'a, 'tc
                              Some(this.body),
                              cfg,
                              LoanDataFlowOperator,
-                             id_range,
                              all_loans.len());
     for (loan_idx, loan) in all_loans.iter().enumerate() {
         loan_dfcx.add_gen(loan.gen_scope.item_local_id(), loan_idx);
@@ -198,7 +191,6 @@ fn build_borrowck_dataflow_data<'a, 'c, 'tcx, F>(this: &mut BorrowckCtxt<'a, 'tc
     let flowed_moves = move_data::FlowedMoveData::new(move_data,
                                                       this,
                                                       cfg,
-                                                      id_range,
                                                       this.body);
 
     Some(AnalysisData { all_loans,
@@ -304,11 +296,11 @@ pub struct Loan<'tcx> {
     /// gen_scope indicates where loan is introduced. Typically the
     /// loan is introduced at the point of the borrow, but in some
     /// cases, notably method arguments, the loan may be introduced
-    /// only later, once it comes into scope.  See also
+    /// only later, once it comes into scope. See also
     /// `GatherLoanCtxt::compute_gen_scope`.
     gen_scope: region::Scope,
 
-    /// kill_scope indicates when the loan goes out of scope.  This is
+    /// kill_scope indicates when the loan goes out of scope. This is
     /// either when the lifetime expires or when the local variable
     /// which roots the loan-path goes out of scope, whichever happens
     /// faster. See also `GatherLoanCtxt::compute_kill_scope`.
@@ -407,12 +399,12 @@ pub enum LoanPathElem<'tcx> {
 }
 
 fn closure_to_block(closure_id: LocalDefId,
-                    tcx: TyCtxt) -> ast::NodeId {
+                    tcx: TyCtxt<'_, '_, '_>) -> ast::NodeId {
     let closure_id = tcx.hir().local_def_id_to_node_id(closure_id);
     match tcx.hir().get(closure_id) {
         Node::Expr(expr) => match expr.node {
             hir::ExprKind::Closure(.., body_id, _, _) => {
-                body_id.node_id
+                tcx.hir().hir_to_node_id(body_id.hir_id)
             }
             _ => {
                 bug!("encountered non-closure id: {}", closure_id)
@@ -859,7 +851,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                                         }) = cmt.cat {
                                             db.note(fn_closure_msg);
                                         } else {
-                                            db.span_suggestion_with_applicability(
+                                            db.span_suggestion(
                                                 sp,
                                                 msg,
                                                 suggestion,
@@ -867,7 +859,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                                             );
                                         }
                                     } else {
-                                        db.span_suggestion_with_applicability(
+                                        db.span_suggestion(
                                             sp,
                                             msg,
                                             suggestion,
@@ -1223,8 +1215,8 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
     }
 
     fn note_immutability_blame(&self,
-                               db: &mut DiagnosticBuilder,
-                               blame: Option<ImmutabilityBlame>,
+                               db: &mut DiagnosticBuilder<'_>,
+                               blame: Option<ImmutabilityBlame<'_>>,
                                error_node_id: ast::NodeId) {
         match blame {
             None => {}
@@ -1238,7 +1230,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                         let let_span = self.tcx.hir().span(node_id);
                         let suggestion = suggest_ref_mut(self.tcx, let_span);
                         if let Some(replace_str) = suggestion {
-                            db.span_suggestion_with_applicability(
+                            db.span_suggestion(
                                 let_span,
                                 "use a mutable reference instead",
                                 replace_str,
@@ -1280,7 +1272,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
      // binding: either to make the binding mutable (if its type is
      // not a mutable reference) or to avoid borrowing altogether
     fn note_immutable_local(&self,
-                            db: &mut DiagnosticBuilder,
+                            db: &mut DiagnosticBuilder<'_>,
                             borrowed_node_id: ast::NodeId,
                             binding_node_id: ast::NodeId) {
         let let_span = self.tcx.hir().span(binding_node_id);
@@ -1300,7 +1292,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                 )) = ty.map(|t| &t.node)
                 {
                     let borrow_expr_id = self.tcx.hir().get_parent_node(borrowed_node_id);
-                    db.span_suggestion_with_applicability(
+                    db.span_suggestion(
                         self.tcx.hir().span(borrow_expr_id),
                         "consider removing the `&mut`, as it is an \
                         immutable binding to a mutable reference",
@@ -1308,7 +1300,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                         Applicability::MachineApplicable,
                     );
                 } else {
-                    db.span_suggestion_with_applicability(
+                    db.span_suggestion(
                         let_span,
                         "make this binding mutable",
                         format!("mut {}", snippet),
@@ -1335,7 +1327,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                                                   &cmt_path_or_string,
                                                   capture_span,
                                                   Origin::Ast)
-            .span_suggestion_with_applicability(
+            .span_suggestion(
                  err.span,
                  &format!("to force the closure to take ownership of {} \
                            (and any other referenced variables), \
@@ -1358,7 +1350,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         }
     }
 
-    fn note_and_explain_mutbl_error(&self, db: &mut DiagnosticBuilder, err: &BckError<'a, 'tcx>,
+    fn note_and_explain_mutbl_error(&self, db: &mut DiagnosticBuilder<'_>, err: &BckError<'a, 'tcx>,
                                     error_span: &Span) {
         match err.cmt.note {
             mc::NoteClosureEnv(upvar_id) | mc::NoteUpvarRef(upvar_id) => {
@@ -1496,7 +1488,7 @@ impl DataFlowOperator for LoanDataFlowOperator {
 }
 
 impl<'tcx> fmt::Debug for InteriorKind {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             InteriorField(mc::FieldIndex(_, info)) => write!(f, "{}", info),
             InteriorElement => write!(f, "[]"),
@@ -1505,7 +1497,7 @@ impl<'tcx> fmt::Debug for InteriorKind {
 }
 
 impl<'tcx> fmt::Debug for Loan<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "Loan_{}({:?}, {:?}, {:?}-{:?}, {:?})",
                self.index,
                self.loan_path,
@@ -1517,7 +1509,7 @@ impl<'tcx> fmt::Debug for Loan<'tcx> {
 }
 
 impl<'tcx> fmt::Debug for LoanPath<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.kind {
             LpVar(id) => {
                 write!(f, "$({})", ty::tls::with(|tcx| tcx.hir().node_to_string(id)))
@@ -1552,7 +1544,7 @@ impl<'tcx> fmt::Debug for LoanPath<'tcx> {
 }
 
 impl<'tcx> fmt::Display for LoanPath<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self.kind {
             LpVar(id) => {
                 write!(f, "$({})", ty::tls::with(|tcx| tcx.hir().node_to_user_string(id)))
diff --git a/src/librustc_borrowck/borrowck/move_data.rs b/src/librustc_borrowck/borrowck/move_data.rs
index c5bee87e90fe4..325d3559f0ab6 100644
--- a/src/librustc_borrowck/borrowck/move_data.rs
+++ b/src/librustc_borrowck/borrowck/move_data.rs
@@ -1,11 +1,11 @@
 //! Data structures used for tracking moves. Please see the extensive
 //! comments in the section "Moves and initialization" in `README.md`.
 
-pub use self::MoveKind::*;
+pub use MoveKind::*;
 
-use dataflow::{DataFlowContext, BitwiseOperator, DataFlowOperator, KillFrom};
+use crate::dataflow::{DataFlowContext, BitwiseOperator, DataFlowOperator, KillFrom};
 
-use borrowck::*;
+use crate::borrowck::*;
 use rustc::cfg;
 use rustc::ty::{self, TyCtxt};
 use rustc::util::nodemap::FxHashMap;
@@ -15,7 +15,7 @@ use std::rc::Rc;
 use std::usize;
 use syntax_pos::Span;
 use rustc::hir;
-use rustc::hir::intravisit::IdRange;
+use log::debug;
 
 #[derive(Default)]
 pub struct MoveData<'tcx> {
@@ -114,7 +114,7 @@ pub struct Move {
     /// Path being moved.
     pub path: MovePathIndex,
 
-    /// id of node that is doing the move.
+    /// ID of node that is doing the move.
     pub id: hir::ItemLocalId,
 
     /// Kind of move, for error messages.
@@ -129,7 +129,7 @@ pub struct Assignment {
     /// Path being assigned.
     pub path: MovePathIndex,
 
-    /// id where assignment occurs
+    /// ID where assignment occurs
     pub id: hir::ItemLocalId,
 
     /// span of node where assignment occurs
@@ -146,7 +146,7 @@ pub struct AssignDataFlowOperator;
 
 pub type AssignDataFlow<'a, 'tcx> = DataFlowContext<'a, 'tcx, AssignDataFlowOperator>;
 
-fn loan_path_is_precise(loan_path: &LoanPath) -> bool {
+fn loan_path_is_precise(loan_path: &LoanPath<'_>) -> bool {
     match loan_path.kind {
         LpVar(_) | LpUpvar(_) => {
             true
@@ -168,8 +168,8 @@ fn loan_path_is_precise(loan_path: &LoanPath) -> bool {
 }
 
 impl<'a, 'tcx> MoveData<'tcx> {
-    /// return true if there are no trackable assignments or moves
-    /// in this move data - that means that there is nothing that
+    /// Returns `true` if there are no trackable assignments or moves
+    /// in this move data -- that means that there is nothing that
     /// could cause a borrow error.
     pub fn is_empty(&self) -> bool {
         self.moves.borrow().is_empty() &&
@@ -429,8 +429,8 @@ impl<'a, 'tcx> MoveData<'tcx> {
     /// killed by scoping. See `README.md` for more details.
     fn add_gen_kills(&self,
                      bccx: &BorrowckCtxt<'a, 'tcx>,
-                     dfcx_moves: &mut MoveDataFlow,
-                     dfcx_assign: &mut AssignDataFlow) {
+                     dfcx_moves: &mut MoveDataFlow<'_, '_>,
+                     dfcx_assign: &mut AssignDataFlow<'_, '_>) {
         for (i, the_move) in self.moves.borrow().iter().enumerate() {
             dfcx_moves.add_gen(the_move.id, i);
         }
@@ -538,7 +538,7 @@ impl<'a, 'tcx> MoveData<'tcx> {
                   path: MovePathIndex,
                   kill_id: hir::ItemLocalId,
                   kill_kind: KillFrom,
-                  dfcx_moves: &mut MoveDataFlow) {
+                  dfcx_moves: &mut MoveDataFlow<'_, '_>) {
         // We can only perform kills for paths that refer to a unique location,
         // since otherwise we may kill a move from one location with an
         // assignment referring to another location.
@@ -559,7 +559,6 @@ impl<'a, 'tcx> FlowedMoveData<'a, 'tcx> {
     pub fn new(move_data: MoveData<'tcx>,
                bccx: &BorrowckCtxt<'a, 'tcx>,
                cfg: &cfg::CFG,
-               id_range: IdRange,
                body: &hir::Body)
                -> FlowedMoveData<'a, 'tcx> {
         let tcx = bccx.tcx;
@@ -570,7 +569,6 @@ impl<'a, 'tcx> FlowedMoveData<'a, 'tcx> {
                                  Some(body),
                                  cfg,
                                  MoveDataFlowOperator,
-                                 id_range,
                                  move_data.moves.borrow().len());
         let mut dfcx_assign =
             DataFlowContext::new(tcx,
@@ -578,7 +576,6 @@ impl<'a, 'tcx> FlowedMoveData<'a, 'tcx> {
                                  Some(body),
                                  cfg,
                                  AssignDataFlowOperator,
-                                 id_range,
                                  move_data.var_assignments.borrow().len());
 
         move_data.add_gen_kills(bccx,
diff --git a/src/librustc_borrowck/borrowck/unused.rs b/src/librustc_borrowck/borrowck/unused.rs
index 7340c7addb505..60a9c18e95ee9 100644
--- a/src/librustc_borrowck/borrowck/unused.rs
+++ b/src/librustc_borrowck/borrowck/unused.rs
@@ -7,7 +7,7 @@ use errors::Applicability;
 use std::slice;
 use syntax::ptr::P;
 
-use borrowck::BorrowckCtxt;
+use crate::borrowck::BorrowckCtxt;
 
 pub fn check<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>, body: &'tcx hir::Body) {
     let mut used_mut = bccx.used_mut_nodes.borrow().clone();
@@ -78,11 +78,12 @@ impl<'a, 'tcx> UnusedMutCx<'a, 'tcx> {
                                      hir_id,
                                      span,
                                      "variable does not need to be mutable")
-                .span_suggestion_short_with_applicability(
+                .span_suggestion_short(
                     mut_span,
                     "remove this `mut`",
                     String::new(),
-                    Applicability::MachineApplicable)
+                    Applicability::MachineApplicable,
+                )
                 .emit();
         }
     }
diff --git a/src/librustc_borrowck/dataflow.rs b/src/librustc_borrowck/dataflow.rs
index 56e25bd89c9ad..de2a3c4cb22a8 100644
--- a/src/librustc_borrowck/dataflow.rs
+++ b/src/librustc_borrowck/dataflow.rs
@@ -10,12 +10,13 @@ use std::io;
 use std::mem;
 use std::usize;
 use syntax::print::pprust::PrintState;
+use log::debug;
 
 use rustc_data_structures::graph::implementation::OUTGOING;
 
 use rustc::util::nodemap::FxHashMap;
 use rustc::hir;
-use rustc::hir::intravisit::{self, IdRange};
+use rustc::hir::intravisit;
 use rustc::hir::print as pprust;
 
 
@@ -80,7 +81,7 @@ pub trait DataFlowOperator : BitwiseOperator {
     fn initial_value(&self) -> bool;
 }
 
-struct PropagationContext<'a, 'b: 'a, 'tcx: 'b, O: 'a> {
+struct PropagationContext<'a, 'b: 'a, 'tcx: 'b, O> {
     dfcx: &'a mut DataFlowContext<'b, 'tcx, O>,
     changed: bool
 }
@@ -99,12 +100,12 @@ impl<'a, 'tcx, O:DataFlowOperator> DataFlowContext<'a, 'tcx, O> {
 }
 
 impl<'a, 'tcx, O:DataFlowOperator> pprust::PpAnn for DataFlowContext<'a, 'tcx, O> {
-    fn nested(&self, state: &mut pprust::State, nested: pprust::Nested) -> io::Result<()> {
+    fn nested(&self, state: &mut pprust::State<'_>, nested: pprust::Nested) -> io::Result<()> {
         pprust::PpAnn::nested(self.tcx.hir(), state, nested)
     }
     fn pre(&self,
-           ps: &mut pprust::State,
-           node: pprust::AnnNode) -> io::Result<()> {
+           ps: &mut pprust::State<'_>,
+           node: pprust::AnnNode<'_>) -> io::Result<()> {
         let id = match node {
             pprust::AnnNode::Name(_) => return Ok(()),
             pprust::AnnNode::Expr(expr) => expr.hir_id.local_id,
@@ -177,7 +178,7 @@ fn build_local_id_to_index(body: Option<&hir::Body>,
 
     return index;
 
-    /// Add mappings from the ast nodes for the formal bindings to
+    /// Adds mappings from the ast nodes for the formal bindings to
     /// the entry-node in the graph.
     fn add_entries_from_fn_body(index: &mut FxHashMap<hir::ItemLocalId, Vec<CFGIndex>>,
                                 body: &hir::Body,
@@ -230,16 +231,15 @@ impl<'a, 'tcx, O:DataFlowOperator> DataFlowContext<'a, 'tcx, O> {
                body: Option<&hir::Body>,
                cfg: &cfg::CFG,
                oper: O,
-               id_range: IdRange,
                bits_per_id: usize) -> DataFlowContext<'a, 'tcx, O> {
         let usize_bits = mem::size_of::<usize>() * 8;
         let words_per_id = (bits_per_id + usize_bits - 1) / usize_bits;
         let num_nodes = cfg.graph.all_nodes().len();
 
-        debug!("DataFlowContext::new(analysis_name: {}, id_range={:?}, \
+        debug!("DataFlowContext::new(analysis_name: {}, \
                                      bits_per_id={}, words_per_id={}) \
                                      num_nodes: {}",
-               analysis_name, id_range, bits_per_id, words_per_id,
+               analysis_name, bits_per_id, words_per_id,
                num_nodes);
 
         let entry = if oper.initial_value() { usize::MAX } else {0};
diff --git a/src/librustc_borrowck/graphviz.rs b/src/librustc_borrowck/graphviz.rs
index adad8c55f2159..77056d4d3eb15 100644
--- a/src/librustc_borrowck/graphviz.rs
+++ b/src/librustc_borrowck/graphviz.rs
@@ -2,16 +2,15 @@
 //! libgraphviz traits, specialized to attaching borrowck analysis
 //! data to rendered labels.
 
-pub use self::Variant::*;
+pub use Variant::*;
 
 pub use rustc::cfg::graphviz::{Node, Edge};
 use rustc::cfg::graphviz as cfg_dot;
 
-use borrowck;
-use borrowck::{BorrowckCtxt, LoanPath};
-use dot;
+use crate::borrowck::{self, BorrowckCtxt, LoanPath};
+use crate::dataflow::{DataFlowOperator, DataFlowContext, EntryOrExit};
+use log::debug;
 use rustc::cfg::CFGIndex;
-use dataflow::{DataFlowOperator, DataFlowContext, EntryOrExit};
 use std::rc::Rc;
 
 #[derive(Debug, Copy, Clone)]
@@ -53,7 +52,7 @@ impl<'a, 'tcx> DataflowLabeller<'a, 'tcx> {
         sets
     }
 
-    fn dataflow_for_variant(&self, e: EntryOrExit, n: &Node, v: Variant) -> String {
+    fn dataflow_for_variant(&self, e: EntryOrExit, n: &Node<'_>, v: Variant) -> String {
         let cfgidx = n.0;
         match v {
             Loans   => self.dataflow_loans_for(e, cfgidx),
@@ -89,7 +88,7 @@ impl<'a, 'tcx> DataflowLabeller<'a, 'tcx> {
         let dfcx = &self.analysis_data.loans;
         let loan_index_to_path = |loan_index| {
             let all_loans = &self.analysis_data.all_loans;
-            let l: &borrowck::Loan = &all_loans[loan_index];
+            let l: &borrowck::Loan<'_> = &all_loans[loan_index];
             l.loan_path()
         };
         self.build_set(e, cfgidx, dfcx, loan_index_to_path)
diff --git a/src/librustc_borrowck/lib.rs b/src/librustc_borrowck/lib.rs
index 14e0381dad1a4..cf4669db87e5e 100644
--- a/src/librustc_borrowck/lib.rs
+++ b/src/librustc_borrowck/lib.rs
@@ -1,26 +1,14 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![allow(non_camel_case_types)]
+#![deny(rust_2018_idioms)]
 
 #![feature(nll)]
-#![feature(quote)]
 
 #![recursion_limit="256"]
 
-#[macro_use] extern crate log;
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc_errors as errors;
-extern crate rustc_data_structures;
-
-// for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
-// refers to the borrowck-specific graphviz adapter traits.
-extern crate graphviz as dot;
 #[macro_use]
 extern crate rustc;
-extern crate rustc_mir;
 
 pub use borrowck::check_crate;
 pub use borrowck::build_borrowck_dataflow_data_for_fn;
diff --git a/src/librustc_codegen_llvm/Cargo.toml b/src/librustc_codegen_llvm/Cargo.toml
index b711502b14b7f..841cf98164eb4 100644
--- a/src/librustc_codegen_llvm/Cargo.toml
+++ b/src/librustc_codegen_llvm/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_codegen_llvm"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_codegen_llvm"
@@ -10,7 +11,7 @@ crate-type = ["dylib"]
 test = false
 
 [dependencies]
-cc = "1.0.1"
+cc = "1.0.1" # Used to locate MSVC
 num_cpus = "1.0"
 rustc-demangle = "0.1.4"
 rustc_llvm = { path = "../librustc_llvm" }
diff --git a/src/librustc_codegen_llvm/abi.rs b/src/librustc_codegen_llvm/abi.rs
index 258d839d32e82..992149f7a47b5 100644
--- a/src/librustc_codegen_llvm/abi.rs
+++ b/src/librustc_codegen_llvm/abi.rs
@@ -1,12 +1,12 @@
-use llvm::{self, AttributePlace};
+use crate::llvm::{self, AttributePlace};
+use crate::builder::Builder;
+use crate::context::CodegenCx;
+use crate::type_::Type;
+use crate::type_of::{LayoutLlvmExt, PointerKind};
+use crate::value::Value;
 use rustc_codegen_ssa::MemFlags;
-use builder::Builder;
-use context::CodegenCx;
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::mir::operand::OperandValue;
-use type_::Type;
-use type_of::{LayoutLlvmExt, PointerKind};
-use value::Value;
 use rustc_target::abi::call::ArgType;
 
 use rustc_codegen_ssa::traits::*;
@@ -174,13 +174,13 @@ pub trait ArgTypeExt<'ll, 'tcx> {
 }
 
 impl ArgTypeExt<'ll, 'tcx> for ArgType<'tcx, Ty<'tcx>> {
-    /// Get the LLVM type for a place of the original Rust type of
+    /// Gets the LLVM type for a place of the original Rust type of
     /// this argument/return, i.e., the result of `type_of::type_of`.
     fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
         self.layout.llvm_type(cx)
     }
 
-    /// Store a direct/indirect value described by this ArgType into a
+    /// Stores a direct/indirect value described by this ArgType into a
     /// place for the original Rust type of this argument/return.
     /// Can be used for both storing formal arguments into Rust variables
     /// or results of call/invoke instructions into their destinations.
diff --git a/src/librustc_codegen_llvm/allocator.rs b/src/librustc_codegen_llvm/allocator.rs
index 56bbaf55f75b4..7430cd3f70961 100644
--- a/src/librustc_codegen_llvm/allocator.rs
+++ b/src/librustc_codegen_llvm/allocator.rs
@@ -1,13 +1,13 @@
 use std::ffi::CString;
 
-use attributes;
+use crate::attributes;
 use libc::c_uint;
 use rustc::middle::allocator::AllocatorKind;
 use rustc::ty::TyCtxt;
 use rustc_allocator::{ALLOCATOR_METHODS, AllocatorTy};
 
-use ModuleLlvm;
-use llvm::{self, False, True};
+use crate::ModuleLlvm;
+use crate::llvm::{self, False, True};
 
 pub(crate) unsafe fn codegen(tcx: TyCtxt, mods: &ModuleLlvm, kind: AllocatorKind) {
     let llcx = &*mods.llcx;
diff --git a/src/librustc_codegen_llvm/asm.rs b/src/librustc_codegen_llvm/asm.rs
index 5c1a8b070c993..4427308f4155d 100644
--- a/src/librustc_codegen_llvm/asm.rs
+++ b/src/librustc_codegen_llvm/asm.rs
@@ -1,8 +1,8 @@
-use llvm;
-use context::CodegenCx;
-use type_of::LayoutLlvmExt;
-use builder::Builder;
-use value::Value;
+use crate::llvm;
+use crate::context::CodegenCx;
+use crate::type_of::LayoutLlvmExt;
+use crate::builder::Builder;
+use crate::value::Value;
 
 use rustc::hir;
 use rustc_codegen_ssa::traits::*;
diff --git a/src/librustc_codegen_llvm/attributes.rs b/src/librustc_codegen_llvm/attributes.rs
index 226b03c99c043..827ebff10f51c 100644
--- a/src/librustc_codegen_llvm/attributes.rs
+++ b/src/librustc_codegen_llvm/attributes.rs
@@ -5,7 +5,7 @@ use std::ffi::CString;
 use rustc::hir::{CodegenFnAttrFlags, CodegenFnAttrs};
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::session::Session;
-use rustc::session::config::Sanitizer;
+use rustc::session::config::{Sanitizer, OptLevel};
 use rustc::ty::{self, TyCtxt, PolyFnSig};
 use rustc::ty::layout::HasTyCtxt;
 use rustc::ty::query::Providers;
@@ -15,15 +15,15 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_target::spec::PanicStrategy;
 use rustc_codegen_ssa::traits::*;
 
-use abi::Abi;
-use attributes;
-use llvm::{self, Attribute};
-use llvm::AttributePlace::Function;
-use llvm_util;
-pub use syntax::attr::{self, InlineAttr};
+use crate::abi::Abi;
+use crate::attributes;
+use crate::llvm::{self, Attribute};
+use crate::llvm::AttributePlace::Function;
+use crate::llvm_util;
+pub use syntax::attr::{self, InlineAttr, OptimizeAttr};
 
-use context::CodegenCx;
-use value::Value;
+use crate::context::CodegenCx;
+use crate::value::Value;
 
 /// Mark LLVM function to use provided inline heuristic.
 #[inline]
@@ -57,13 +57,6 @@ fn unwind(val: &'ll Value, can_unwind: bool) {
     Attribute::NoUnwind.toggle_llfn(Function, val, !can_unwind);
 }
 
-/// Tell LLVM whether it should optimize function for size.
-#[inline]
-#[allow(dead_code)] // possibly useful function
-pub fn set_optimize_for_size(val: &'ll Value, optimize: bool) {
-    Attribute::OptimizeForSize.toggle_llfn(Function, val, optimize);
-}
-
 /// Tell LLVM if this function should be 'naked', i.e., skip the epilogue and prologue.
 #[inline]
 pub fn naked(val: &'ll Value, is_naked: bool) {
@@ -151,6 +144,28 @@ pub fn non_lazy_bind(sess: &Session, llfn: &'ll Value) {
     }
 }
 
+pub(crate) fn default_optimisation_attrs(sess: &Session, llfn: &'ll Value) {
+    match sess.opts.optimize {
+        OptLevel::Size => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        },
+        OptLevel::SizeMin => {
+            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        OptLevel::No => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        _ => {}
+    }
+}
+
+
 /// Composite function which sets LLVM attributes for function depending on its AST (`#[attribute]`)
 /// attributes.
 pub fn from_fn_attrs(
@@ -162,6 +177,22 @@ pub fn from_fn_attrs(
     let codegen_fn_attrs = id.map(|id| cx.tcx.codegen_fn_attrs(id))
         .unwrap_or_else(|| CodegenFnAttrs::new());
 
+    match codegen_fn_attrs.optimize {
+        OptimizeAttr::None => {
+            default_optimisation_attrs(cx.tcx.sess, llfn);
+        }
+        OptimizeAttr::Speed => {
+            llvm::Attribute::MinSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.unapply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+        OptimizeAttr::Size => {
+            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
+            llvm::Attribute::OptimizeNone.unapply_llfn(Function, llfn);
+        }
+    }
+
     inline(cx, llfn, codegen_fn_attrs.inline);
 
     // The `uwtable` attribute according to LLVM is:
diff --git a/src/librustc_codegen_llvm/back/archive.rs b/src/librustc_codegen_llvm/back/archive.rs
index 1cf150dad6025..1c090f1446965 100644
--- a/src/librustc_codegen_llvm/back/archive.rs
+++ b/src/librustc_codegen_llvm/back/archive.rs
@@ -7,12 +7,11 @@ use std::path::{Path, PathBuf};
 use std::ptr;
 use std::str;
 
-use back::bytecode::RLIB_BYTECODE_EXTENSION;
+use crate::back::bytecode::RLIB_BYTECODE_EXTENSION;
+use crate::llvm::archive_ro::{ArchiveRO, Child};
+use crate::llvm::{self, ArchiveKind};
+use crate::metadata::METADATA_FILENAME;
 use rustc_codegen_ssa::back::archive::find_library;
-use libc;
-use llvm::archive_ro::{ArchiveRO, Child};
-use llvm::{self, ArchiveKind};
-use metadata::METADATA_FILENAME;
 use rustc::session::Session;
 
 pub struct ArchiveConfig<'a> {
@@ -51,7 +50,7 @@ fn is_relevant_child(c: &Child) -> bool {
 }
 
 impl<'a> ArchiveBuilder<'a> {
-    /// Create a new static archive, ready for modifying the archive specified
+    /// Creates a new static archive, ready for modifying the archive specified
     /// by `config`.
     pub fn new(config: ArchiveConfig<'a>) -> ArchiveBuilder<'a> {
         ArchiveBuilder {
diff --git a/src/librustc_codegen_llvm/back/link.rs b/src/librustc_codegen_llvm/back/link.rs
index fc744201a332c..a3b34485715a7 100644
--- a/src/librustc_codegen_llvm/back/link.rs
+++ b/src/librustc_codegen_llvm/back/link.rs
@@ -1,13 +1,15 @@
-use back::wasm;
 use super::archive::{ArchiveBuilder, ArchiveConfig};
 use super::bytecode::RLIB_BYTECODE_EXTENSION;
+use super::rpath::RPathConfig;
+use super::rpath;
+use crate::back::wasm;
+use crate::metadata::METADATA_FILENAME;
+use crate::context::get_reloc_model;
+use crate::llvm;
 use rustc_codegen_ssa::back::linker::Linker;
 use rustc_codegen_ssa::back::link::{remove, ignored_for_lto, each_linked_rlib, linker_and_flavor,
     get_linker};
 use rustc_codegen_ssa::back::command::Command;
-use super::rpath::RPathConfig;
-use super::rpath;
-use metadata::METADATA_FILENAME;
 use rustc::session::config::{self, DebugInfo, OutputFilenames, OutputType, PrintRequest};
 use rustc::session::config::{RUST_CGU_EXT, Lto, Sanitizer};
 use rustc::session::filesearch;
@@ -22,8 +24,6 @@ use rustc::hir::def_id::CrateNum;
 use tempfile::{Builder as TempFileBuilder, TempDir};
 use rustc_target::spec::{PanicStrategy, RelroLevel, LinkerFlavor};
 use rustc_data_structures::fx::FxHashSet;
-use context::get_reloc_model;
-use llvm;
 
 use std::ascii;
 use std::char;
@@ -42,7 +42,7 @@ pub use rustc_codegen_utils::link::{find_crate_name, filename_for_input, default
                                     out_filename, check_file_is_writeable};
 
 
-/// Perform the linkage portion of the compilation phase. This will generate all
+/// Performs the linkage portion of the compilation phase. This will generate all
 /// of the requested outputs for this compilation session.
 pub(crate) fn link_binary(sess: &Session,
                           codegen_results: &CodegenResults,
@@ -523,7 +523,7 @@ fn link_natively(sess: &Session,
     }
 
     {
-        let target_cpu = ::llvm_util::target_cpu(sess);
+        let target_cpu = crate::llvm_util::target_cpu(sess);
         let mut linker = codegen_results.linker_info.to_linker(cmd, &sess, flavor, target_cpu);
         link_args(&mut *linker, flavor, sess, crate_type, tmpdir,
                   out_filename, codegen_results);
@@ -857,7 +857,7 @@ fn link_args(cmd: &mut dyn Linker,
              codegen_results: &CodegenResults) {
 
     // Linker plugins should be specified early in the list of arguments
-    cmd.cross_lang_lto();
+    cmd.linker_plugin_lto();
 
     // The default library location, we need this to find the runtime.
     // The location of crates will be determined as needed.
@@ -1491,7 +1491,7 @@ fn are_upstream_rust_objects_already_included(sess: &Session) -> bool {
         Lto::Thin => {
             // If we defer LTO to the linker, we haven't run LTO ourselves, so
             // any upstream object files have not been copied yet.
-            !sess.opts.debugging_opts.cross_lang_lto.enabled()
+            !sess.opts.cg.linker_plugin_lto.enabled()
         }
         Lto::No |
         Lto::ThinLocal => false,
diff --git a/src/librustc_codegen_llvm/back/lto.rs b/src/librustc_codegen_llvm/back/lto.rs
index 5d5f1ceceb88c..944569c8b744b 100644
--- a/src/librustc_codegen_llvm/back/lto.rs
+++ b/src/librustc_codegen_llvm/back/lto.rs
@@ -1,12 +1,15 @@
-use back::bytecode::{DecodedBytecode, RLIB_BYTECODE_EXTENSION};
+use crate::back::bytecode::{DecodedBytecode, RLIB_BYTECODE_EXTENSION};
+use crate::back::write::{self, DiagnosticHandlers, with_llvm_pmb, save_temp_bitcode,
+    to_llvm_opt_settings};
+use crate::llvm::archive_ro::ArchiveRO;
+use crate::llvm::{self, True, False};
+use crate::time_graph::Timeline;
+use crate::{ModuleLlvm, LlvmCodegenBackend};
 use rustc_codegen_ssa::back::symbol_export;
-use rustc_codegen_ssa::back::write::{ModuleConfig, CodegenContext, pre_lto_bitcode_filename};
+use rustc_codegen_ssa::back::write::{ModuleConfig, CodegenContext, FatLTOInput};
 use rustc_codegen_ssa::back::lto::{SerializedModule, LtoModuleCodegen, ThinShared, ThinModule};
 use rustc_codegen_ssa::traits::*;
-use back::write::{self, DiagnosticHandlers, with_llvm_pmb, save_temp_bitcode, get_llvm_opt_level};
 use errors::{FatalError, Handler};
-use llvm::archive_ro::ArchiveRO;
-use llvm::{self, True, False};
 use rustc::dep_graph::WorkProduct;
 use rustc::dep_graph::cgu_reuse_tracker::CguReuse;
 use rustc::hir::def_id::LOCAL_CRATE;
@@ -14,14 +17,9 @@ use rustc::middle::exported_symbols::SymbolExportLevel;
 use rustc::session::config::{self, Lto};
 use rustc::util::common::time_ext;
 use rustc_data_structures::fx::FxHashMap;
-use time_graph::Timeline;
-use {ModuleLlvm, LlvmCodegenBackend};
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 
-use libc;
-
 use std::ffi::{CStr, CString};
-use std::fs;
 use std::ptr;
 use std::slice;
 use std::sync::Arc;
@@ -133,7 +131,8 @@ fn prepare_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
 /// Performs fat LTO by merging all modules into a single one and returning it
 /// for further optimization.
 pub(crate) fn run_fat(cgcx: &CodegenContext<LlvmCodegenBackend>,
-                      modules: Vec<ModuleCodegen<ModuleLlvm>>,
+                      modules: Vec<FatLTOInput<LlvmCodegenBackend>>,
+                      cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
                       timeline: &mut Timeline)
     -> Result<LtoModuleCodegen<LlvmCodegenBackend>, FatalError>
 {
@@ -142,7 +141,15 @@ pub(crate) fn run_fat(cgcx: &CodegenContext<LlvmCodegenBackend>,
     let symbol_white_list = symbol_white_list.iter()
                                              .map(|c| c.as_ptr())
                                              .collect::<Vec<_>>();
-    fat_lto(cgcx, &diag_handler, modules, upstream_modules, &symbol_white_list, timeline)
+    fat_lto(
+        cgcx,
+        &diag_handler,
+        modules,
+        cached_modules,
+        upstream_modules,
+        &symbol_white_list,
+        timeline,
+    )
 }
 
 /// Performs thin LTO by performing necessary global analysis and returning two
@@ -159,7 +166,7 @@ pub(crate) fn run_thin(cgcx: &CodegenContext<LlvmCodegenBackend>,
     let symbol_white_list = symbol_white_list.iter()
                                              .map(|c| c.as_ptr())
                                              .collect::<Vec<_>>();
-    if cgcx.opts.debugging_opts.cross_lang_lto.enabled() {
+    if cgcx.opts.cg.linker_plugin_lto.enabled() {
         unreachable!("We should never reach this case if the LTO step \
                       is deferred to the linker");
     }
@@ -173,33 +180,17 @@ pub(crate) fn run_thin(cgcx: &CodegenContext<LlvmCodegenBackend>,
 }
 
 pub(crate) fn prepare_thin(
-    cgcx: &CodegenContext<LlvmCodegenBackend>,
     module: ModuleCodegen<ModuleLlvm>
 ) -> (String, ThinBuffer) {
     let name = module.name.clone();
     let buffer = ThinBuffer::new(module.module_llvm.llmod());
-
-    // We emit the module after having serialized it into a ThinBuffer
-    // because only then it will contain the ThinLTO module summary.
-    if let Some(ref incr_comp_session_dir) = cgcx.incr_comp_session_dir {
-        if cgcx.config(module.kind).emit_pre_thin_lto_bc {
-            let path = incr_comp_session_dir
-                .join(pre_lto_bitcode_filename(&name));
-
-            fs::write(&path, buffer.data()).unwrap_or_else(|e| {
-                panic!("Error writing pre-lto-bitcode file `{}`: {}",
-                       path.display(),
-                       e);
-            });
-        }
-    }
-
     (name, buffer)
 }
 
 fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
            diag_handler: &Handler,
-           mut modules: Vec<ModuleCodegen<ModuleLlvm>>,
+           mut modules: Vec<FatLTOInput<LlvmCodegenBackend>>,
+           cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
            mut serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
            symbol_white_list: &[*const libc::c_char],
            timeline: &mut Timeline)
@@ -216,8 +207,14 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
     // file copy operations in the backend work correctly. The only other kind
     // of module here should be an allocator one, and if your crate is smaller
     // than the allocator module then the size doesn't really matter anyway.
-    let (_, costliest_module) = modules.iter()
+    let costliest_module = modules.iter()
         .enumerate()
+        .filter_map(|(i, module)| {
+            match module {
+                FatLTOInput::InMemory(m) => Some((i, m)),
+                FatLTOInput::Serialized { .. } => None,
+            }
+        })
         .filter(|&(_, module)| module.kind == ModuleKind::Regular)
         .map(|(i, module)| {
             let cost = unsafe {
@@ -225,9 +222,38 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
             };
             (cost, i)
         })
-        .max()
-        .expect("must be codegen'ing at least one module");
-    let module = modules.remove(costliest_module);
+        .max();
+
+    // If we found a costliest module, we're good to go. Otherwise all our
+    // inputs were serialized which could happen in the case, for example, that
+    // all our inputs were incrementally reread from the cache and we're just
+    // re-executing the LTO passes. If that's the case deserialize the first
+    // module and create a linker with it.
+    let module: ModuleCodegen<ModuleLlvm> = match costliest_module {
+        Some((_cost, i)) => {
+            match modules.remove(i) {
+                FatLTOInput::InMemory(m) => m,
+                FatLTOInput::Serialized { .. } => unreachable!(),
+            }
+        }
+        None => {
+            let pos = modules.iter().position(|m| {
+                match m {
+                    FatLTOInput::InMemory(_) => false,
+                    FatLTOInput::Serialized { .. } => true,
+                }
+            }).expect("must have at least one serialized module");
+            let (name, buffer) = match modules.remove(pos) {
+                FatLTOInput::Serialized { name, buffer } => (name, buffer),
+                FatLTOInput::InMemory(_) => unreachable!(),
+            };
+            ModuleCodegen {
+                module_llvm: ModuleLlvm::parse(cgcx, &name, &buffer, diag_handler)?,
+                name,
+                kind: ModuleKind::Regular,
+            }
+        }
+    };
     let mut serialized_bitcode = Vec::new();
     {
         let (llcx, llmod) = {
@@ -247,10 +273,20 @@ fn fat_lto(cgcx: &CodegenContext<LlvmCodegenBackend>,
         // way we know of to do that is to serialize them to a string and them parse
         // them later. Not great but hey, that's why it's "fat" LTO, right?
         serialized_modules.extend(modules.into_iter().map(|module| {
-            let buffer = ModuleBuffer::new(module.module_llvm.llmod());
-            let llmod_id = CString::new(&module.name[..]).unwrap();
-
-            (SerializedModule::Local(buffer), llmod_id)
+            match module {
+                FatLTOInput::InMemory(module) => {
+                    let buffer = ModuleBuffer::new(module.module_llvm.llmod());
+                    let llmod_id = CString::new(&module.name[..]).unwrap();
+                    (SerializedModule::Local(buffer), llmod_id)
+                }
+                FatLTOInput::Serialized { name, buffer } => {
+                    let llmod_id = CString::new(name).unwrap();
+                    (SerializedModule::Local(buffer), llmod_id)
+                }
+            }
+        }));
+        serialized_modules.extend(cached_modules.into_iter().map(|(buffer, wp)| {
+            (buffer, CString::new(wp.cgu_name.clone()).unwrap())
         }));
 
         // For all serialized bitcode files we parse them and link them in as we did
@@ -532,7 +568,7 @@ pub(crate) fn run_pass_manager(cgcx: &CodegenContext<LlvmCodegenBackend>,
         // Note that in general this shouldn't matter too much as you typically
         // only turn on ThinLTO when you're compiling with optimizations
         // otherwise.
-        let opt_level = config.opt_level.map(get_llvm_opt_level)
+        let opt_level = config.opt_level.map(|x| to_llvm_opt_settings(x).0)
             .unwrap_or(llvm::CodeGenOptLevel::None);
         let opt_level = match opt_level {
             llvm::CodeGenOptLevel::None => llvm::CodeGenOptLevel::Less,
@@ -579,6 +615,16 @@ impl ModuleBuffer {
             llvm::LLVMRustModuleBufferCreate(m)
         })
     }
+
+    pub fn parse<'a>(
+        &self,
+        name: &str,
+        cx: &'a llvm::Context,
+        handler: &Handler,
+    ) -> Result<&'a llvm::Module, FatalError> {
+        let name = CString::new(name).unwrap();
+        parse_module(cx, &name, self.data(), handler)
+    }
 }
 
 impl ModuleBufferMethods for ModuleBuffer {
@@ -658,15 +704,12 @@ pub unsafe fn optimize_thin_module(
     // crates but for locally codegened modules we may be able to reuse
     // that LLVM Context and Module.
     let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
-    let llmod_raw = llvm::LLVMRustParseBitcodeForThinLTO(
+    let llmod_raw = parse_module(
         llcx,
-        thin_module.data().as_ptr(),
-        thin_module.data().len(),
-        thin_module.shared.module_names[thin_module.idx].as_ptr(),
-    ).ok_or_else(|| {
-        let msg = "failed to parse bitcode for thin LTO module";
-        write::llvm_err(&diag_handler, msg)
-    })? as *const _;
+        &thin_module.shared.module_names[thin_module.idx],
+        thin_module.data(),
+        &diag_handler,
+    )? as *const _;
     let module = ModuleCodegen {
         module_llvm: ModuleLlvm {
             llmod_raw,
@@ -791,7 +834,7 @@ impl ThinLTOImports {
         self.imports.get(llvm_module_name).map(|v| &v[..]).unwrap_or(&[])
     }
 
-    /// Load the ThinLTO import map from ThinLTOData.
+    /// Loads the ThinLTO import map from ThinLTOData.
     unsafe fn from_thin_lto_data(data: *const llvm::ThinLTOData) -> ThinLTOImports {
         unsafe extern "C" fn imported_module_callback(payload: *mut libc::c_void,
                                                       importing_module_name: *const libc::c_char,
@@ -823,3 +866,22 @@ fn module_name_to_str(c_str: &CStr) -> &str {
     c_str.to_str().unwrap_or_else(|e|
         bug!("Encountered non-utf8 LLVM module name `{}`: {}", c_str.to_string_lossy(), e))
 }
+
+fn parse_module<'a>(
+    cx: &'a llvm::Context,
+    name: &CStr,
+    data: &[u8],
+    diag_handler: &Handler,
+) -> Result<&'a llvm::Module, FatalError> {
+    unsafe {
+        llvm::LLVMRustParseBitcodeForLTO(
+            cx,
+            data.as_ptr(),
+            data.len(),
+            name.as_ptr(),
+        ).ok_or_else(|| {
+            let msg = "failed to parse bitcode for LTO module";
+            write::llvm_err(&diag_handler, msg)
+        })
+    }
+}
diff --git a/src/librustc_codegen_llvm/back/rpath.rs b/src/librustc_codegen_llvm/back/rpath.rs
index aeff23dec41bb..a5c828e089f39 100644
--- a/src/librustc_codegen_llvm/back/rpath.rs
+++ b/src/librustc_codegen_llvm/back/rpath.rs
@@ -101,9 +101,9 @@ fn get_rpath_relative_to_output(config: &mut RPathConfig, lib: &Path) -> String
 
     let cwd = env::current_dir().unwrap();
     let mut lib = fs::canonicalize(&cwd.join(lib)).unwrap_or_else(|_| cwd.join(lib));
-    lib.pop();
+    lib.pop(); // strip filename
     let mut output = cwd.join(&config.out_filename);
-    output.pop();
+    output.pop(); // strip filename
     let output = fs::canonicalize(&output).unwrap_or(output);
     let relative = path_relative_from(&lib, &output).unwrap_or_else(||
         panic!("couldn't create relative path from {:?} to {:?}", output, lib));
diff --git a/src/librustc_codegen_llvm/back/wasm.rs b/src/librustc_codegen_llvm/back/wasm.rs
index 3501123a37f51..b403660fa512d 100644
--- a/src/librustc_codegen_llvm/back/wasm.rs
+++ b/src/librustc_codegen_llvm/back/wasm.rs
@@ -112,7 +112,7 @@ pub fn rewrite_imports(path: &Path, import_map: &FxHashMap<String, String>) {
     }
 }
 
-/// Add or augment the existing `producers` section to encode information about
+/// Adds or augment the existing `producers` section to encode information about
 /// the Rust compiler used to produce the wasm file.
 pub fn add_producer_section(
     path: &Path,
diff --git a/src/librustc_codegen_llvm/back/write.rs b/src/librustc_codegen_llvm/back/write.rs
index c0a4f5aa44047..1b16080515235 100644
--- a/src/librustc_codegen_llvm/back/write.rs
+++ b/src/librustc_codegen_llvm/back/write.rs
@@ -1,26 +1,27 @@
-use attributes;
-use back::bytecode::{self, RLIB_BYTECODE_EXTENSION};
-use back::lto::ThinBuffer;
+use crate::attributes;
+use crate::back::bytecode::{self, RLIB_BYTECODE_EXTENSION};
+use crate::back::lto::ThinBuffer;
+use crate::base;
+use crate::consts;
+use crate::time_graph::Timeline;
+use crate::llvm::{self, DiagnosticInfo, PassManager, SMDiagnostic};
+use crate::llvm_util;
+use crate::ModuleLlvm;
+use crate::type_::Type;
+use crate::context::{is_pie_binary, get_reloc_model};
+use crate::common;
+use crate::LlvmCodegenBackend;
 use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, run_assembler};
 use rustc_codegen_ssa::traits::*;
-use base;
-use consts;
+use rustc::hir::def_id::LOCAL_CRATE;
 use rustc::session::config::{self, OutputType, Passes, Lto};
 use rustc::session::Session;
-use time_graph::Timeline;
-use llvm::{self, DiagnosticInfo, PassManager, SMDiagnostic};
-use llvm_util;
-use ModuleLlvm;
+use rustc::ty::TyCtxt;
 use rustc_codegen_ssa::{ModuleCodegen, CompiledModule};
 use rustc::util::common::time_ext;
 use rustc_fs_util::{path_to_c_string, link_or_copy};
 use rustc_data_structures::small_c_str::SmallCStr;
-use errors::{self, Handler, FatalError};
-use type_::Type;
-use context::{is_pie_binary, get_reloc_model};
-use common;
-use LlvmCodegenBackend;
-use rustc_demangle;
+use errors::{Handler, FatalError};
 
 use std::ffi::{CString, CStr};
 use std::fs;
@@ -81,42 +82,46 @@ pub fn write_output_file(
     }
 }
 
-pub(crate) fn get_llvm_opt_level(optimize: config::OptLevel) -> llvm::CodeGenOptLevel {
-    match optimize {
-      config::OptLevel::No => llvm::CodeGenOptLevel::None,
-      config::OptLevel::Less => llvm::CodeGenOptLevel::Less,
-      config::OptLevel::Default => llvm::CodeGenOptLevel::Default,
-      config::OptLevel::Aggressive => llvm::CodeGenOptLevel::Aggressive,
-      _ => llvm::CodeGenOptLevel::Default,
-    }
-}
-
-pub(crate) fn get_llvm_opt_size(optimize: config::OptLevel) -> llvm::CodeGenOptSize {
-    match optimize {
-      config::OptLevel::Size => llvm::CodeGenOptSizeDefault,
-      config::OptLevel::SizeMin => llvm::CodeGenOptSizeAggressive,
-      _ => llvm::CodeGenOptSizeNone,
-    }
+pub fn create_target_machine(
+    tcx: TyCtxt,
+    find_features: bool,
+) -> &'static mut llvm::TargetMachine {
+    target_machine_factory(tcx.sess, tcx.backend_optimization_level(LOCAL_CRATE), find_features)()
+        .unwrap_or_else(|err| llvm_err(tcx.sess.diagnostic(), &err).raise() )
 }
 
-pub fn create_target_machine(
+pub fn create_informational_target_machine(
     sess: &Session,
     find_features: bool,
 ) -> &'static mut llvm::TargetMachine {
-    target_machine_factory(sess, find_features)().unwrap_or_else(|err| {
+    target_machine_factory(sess, config::OptLevel::No, find_features)().unwrap_or_else(|err| {
         llvm_err(sess.diagnostic(), &err).raise()
     })
 }
 
+
+pub fn to_llvm_opt_settings(cfg: config::OptLevel) -> (llvm::CodeGenOptLevel, llvm::CodeGenOptSize)
+{
+    use self::config::OptLevel::*;
+    match cfg {
+        No => (llvm::CodeGenOptLevel::None, llvm::CodeGenOptSizeNone),
+        Less => (llvm::CodeGenOptLevel::Less, llvm::CodeGenOptSizeNone),
+        Default => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeNone),
+        Aggressive => (llvm::CodeGenOptLevel::Aggressive, llvm::CodeGenOptSizeNone),
+        Size => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeDefault),
+        SizeMin => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeAggressive),
+    }
+}
+
 // If find_features is true this won't access `sess.crate_types` by assuming
 // that `is_pie_binary` is false. When we discover LLVM target features
 // `sess.crate_types` is uninitialized so we cannot access it.
-pub fn target_machine_factory(sess: &Session, find_features: bool)
+pub fn target_machine_factory(sess: &Session, optlvl: config::OptLevel, find_features: bool)
     -> Arc<dyn Fn() -> Result<&'static mut llvm::TargetMachine, String> + Send + Sync>
 {
     let reloc_model = get_reloc_model(sess);
 
-    let opt_level = get_llvm_opt_level(sess.opts.optimize);
+    let (opt_level, _) = to_llvm_opt_settings(optlvl);
     let use_softfp = sess.opts.cg.soft_float;
 
     let ffunction_sections = sess.target.target.options.function_sections;
@@ -357,10 +362,10 @@ pub(crate) unsafe fn optimize(cgcx: &CodegenContext<LlvmCodegenBackend>,
             if !config.no_prepopulate_passes {
                 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
                 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
-                let opt_level = config.opt_level.map(get_llvm_opt_level)
+                let opt_level = config.opt_level.map(|x| to_llvm_opt_settings(x).0)
                     .unwrap_or(llvm::CodeGenOptLevel::None);
                 let prepare_for_thin_lto = cgcx.lto == Lto::Thin || cgcx.lto == Lto::ThinLocal ||
-                    (cgcx.lto != Lto::Fat && cgcx.opts.debugging_opts.cross_lang_lto.enabled());
+                    (cgcx.lto != Lto::Fat && cgcx.opts.cg.linker_plugin_lto.enabled());
                 with_llvm_pmb(llmod, &config, opt_level, prepare_for_thin_lto, &mut |b| {
                     llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(b, fpm);
                     llvm::LLVMPassManagerBuilderPopulateModulePassManager(b, mpm);
@@ -689,7 +694,8 @@ pub unsafe fn with_llvm_pmb(llmod: &llvm::Module,
     // reasonable defaults and prepare it to actually populate the pass
     // manager.
     let builder = llvm::LLVMPassManagerBuilderCreate();
-    let opt_size = config.opt_size.map(get_llvm_opt_size).unwrap_or(llvm::CodeGenOptSizeNone);
+    let opt_size = config.opt_size.map(|x| to_llvm_opt_settings(x).1)
+        .unwrap_or(llvm::CodeGenOptSizeNone);
     let inline_threshold = config.inline_threshold;
 
     let pgo_gen_path = config.pgo_gen.as_ref().map(|s| {
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 6a0d5fa1e1fd8..33531bb69485b 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -7,28 +7,29 @@
 //!
 //! Hopefully useful general knowledge about codegen:
 //!
-//!   * There's no way to find out the Ty type of a Value.  Doing so
-//!     would be "trying to get the eggs out of an omelette" (credit:
-//!     pcwalton).  You can, instead, find out its llvm::Type by calling val_ty,
-//!     but one llvm::Type corresponds to many `Ty`s; for instance, tup(int, int,
-//!     int) and rec(x=int, y=int, z=int) will have the same llvm::Type.
+//! * There's no way to find out the `Ty` type of a Value. Doing so
+//!   would be "trying to get the eggs out of an omelette" (credit:
+//!   pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`,
+//!   but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int,
+//!   int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`.
 
 use super::ModuleLlvm;
 use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
 use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
 use super::LlvmCodegenBackend;
 
-use llvm;
-use metadata;
+use crate::llvm;
+use crate::metadata;
+use crate::builder::Builder;
+use crate::common;
+use crate::context::CodegenCx;
+use crate::monomorphize::partitioning::CodegenUnitExt;
+use rustc::dep_graph;
 use rustc::mir::mono::{Linkage, Visibility, Stats};
 use rustc::middle::cstore::{EncodedMetadata};
 use rustc::ty::TyCtxt;
 use rustc::middle::exported_symbols;
 use rustc::session::config::{self, DebugInfo};
-use builder::Builder;
-use common;
-use context::CodegenCx;
-use monomorphize::partitioning::CodegenUnitExt;
 use rustc_codegen_ssa::mono_item::MonoItemExt;
 use rustc_data_structures::small_c_str::SmallCStr;
 
@@ -40,7 +41,7 @@ use std::time::Instant;
 use syntax_pos::symbol::InternedString;
 use rustc::hir::CodegenFnAttrs;
 
-use value::Value;
+use crate::value::Value;
 
 
 pub fn write_metadata<'a, 'gcx>(
@@ -136,7 +137,7 @@ pub fn iter_globals(llmod: &'ll llvm::Module) -> ValueIter<'ll> {
     }
 }
 
-pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
+pub fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                   cgu_name: InternedString)
                                   -> Stats {
     let start_time = Instant::now();
@@ -145,7 +146,8 @@ pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
     let ((stats, module), _) = tcx.dep_graph.with_task(dep_node,
                                                        tcx,
                                                        cgu_name,
-                                                       module_codegen);
+                                                       module_codegen,
+                                                       dep_graph::hash_result);
     let time_to_codegen = start_time.elapsed();
 
     // We assume that the cost to run LLVM on a CGU is proportional to
@@ -164,7 +166,7 @@ pub fn compile_codegen_unit<'ll, 'tcx>(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
         let backend = LlvmCodegenBackend(());
         let cgu = tcx.codegen_unit(cgu_name);
         // Instantiate monomorphizations without filling out definitions yet...
-        let llvm_module = backend.new_metadata(tcx.sess, &cgu_name.as_str());
+        let llvm_module = backend.new_metadata(tcx, &cgu_name.as_str());
         let stats = {
             let cx = CodegenCx::new(tcx, cgu, &llvm_module);
             let mono_items = cx.codegen_unit
diff --git a/src/librustc_codegen_llvm/builder.rs b/src/librustc_codegen_llvm/builder.rs
index b79d0da0bcd06..39c8f8a09400b 100644
--- a/src/librustc_codegen_llvm/builder.rs
+++ b/src/librustc_codegen_llvm/builder.rs
@@ -1,12 +1,12 @@
-use llvm::{AtomicRmwBinOp, AtomicOrdering, SynchronizationScope, AsmDialect};
-use llvm::{self, False, BasicBlock};
+use crate::llvm::{AtomicRmwBinOp, AtomicOrdering, SynchronizationScope, AsmDialect};
+use crate::llvm::{self, False, BasicBlock};
+use crate::common::Funclet;
+use crate::context::CodegenCx;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::value::Value;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind, RealPredicate};
-use rustc_codegen_ssa::{self, MemFlags};
-use common::Funclet;
-use context::CodegenCx;
-use type_::Type;
-use type_of::LayoutLlvmExt;
-use value::Value;
+use rustc_codegen_ssa::MemFlags;
 use libc::{c_uint, c_char};
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::ty::layout::{self, Align, Size, TyLayout};
@@ -14,7 +14,6 @@ use rustc::hir::def_id::DefId;
 use rustc::session::config;
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_codegen_ssa::traits::*;
-use syntax;
 use rustc_codegen_ssa::base::to_immediate;
 use rustc_codegen_ssa::mir::operand::{OperandValue, OperandRef};
 use rustc_codegen_ssa::mir::place::PlaceRef;
diff --git a/src/librustc_codegen_llvm/callee.rs b/src/librustc_codegen_llvm/callee.rs
index 0d9d6aa5aa20f..43a5767e5c68d 100644
--- a/src/librustc_codegen_llvm/callee.rs
+++ b/src/librustc_codegen_llvm/callee.rs
@@ -1,14 +1,14 @@
 //! Handles codegen of callees as well as other call-related
-//! things.  Callees are a superset of normal rust values and sometimes
-//! have different representations.  In particular, top-level fn items
+//! things. Callees are a superset of normal rust values and sometimes
+//! have different representations. In particular, top-level fn items
 //! and methods are represented as just a fn ptr and not a full
 //! closure.
 
-use attributes;
-use llvm;
-use monomorphize::Instance;
-use context::CodegenCx;
-use value::Value;
+use crate::attributes;
+use crate::llvm;
+use crate::monomorphize::Instance;
+use crate::context::CodegenCx;
+use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
 
 use rustc::ty::TypeFoldable;
diff --git a/src/librustc_codegen_llvm/common.rs b/src/librustc_codegen_llvm/common.rs
index 675d6ccb5041d..4bd036ea3b17a 100644
--- a/src/librustc_codegen_llvm/common.rs
+++ b/src/librustc_codegen_llvm/common.rs
@@ -2,17 +2,17 @@
 
 //! Code that is useful in various codegen modules.
 
-use llvm::{self, True, False, Bool, BasicBlock, OperandBundleDef};
-use abi;
-use consts;
-use type_::Type;
-use type_of::LayoutLlvmExt;
-use value::Value;
+use crate::llvm::{self, True, False, Bool, BasicBlock, OperandBundleDef};
+use crate::abi;
+use crate::consts;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
 
+use crate::consts::const_alloc_to_llvm;
 use rustc::ty::layout::{HasDataLayout, LayoutOf, self, TyLayout, Size};
 use rustc::mir::interpret::{Scalar, AllocKind, Allocation};
-use consts::const_alloc_to_llvm;
 use rustc_codegen_ssa::mir::place::PlaceRef;
 
 use libc::{c_uint, c_char};
@@ -20,7 +20,7 @@ use libc::{c_uint, c_char};
 use syntax::symbol::LocalInternedString;
 use syntax::ast::Mutability;
 
-pub use context::CodegenCx;
+pub use crate::context::CodegenCx;
 
 /*
 * A note on nomenclature of linking: "extern", "foreign", and "upcall".
diff --git a/src/librustc_codegen_llvm/consts.rs b/src/librustc_codegen_llvm/consts.rs
index b7a9382c338bd..6232d44df5e4e 100644
--- a/src/librustc_codegen_llvm/consts.rs
+++ b/src/librustc_codegen_llvm/consts.rs
@@ -1,20 +1,20 @@
+use crate::llvm::{self, SetUnnamedAddr, True};
+use crate::debuginfo;
+use crate::monomorphize::MonoItem;
+use crate::common::CodegenCx;
+use crate::monomorphize::Instance;
+use crate::base;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::value::Value;
 use libc::c_uint;
-use llvm::{self, SetUnnamedAddr, True};
 use rustc::hir::def_id::DefId;
 use rustc::mir::interpret::{ConstValue, Allocation, read_target_uint,
     Pointer, ErrorHandled, GlobalId};
 use rustc::hir::Node;
-use debuginfo;
-use monomorphize::MonoItem;
-use common::CodegenCx;
-use monomorphize::Instance;
 use syntax_pos::Span;
 use rustc_target::abi::HasDataLayout;
 use syntax_pos::symbol::LocalInternedString;
-use base;
-use type_::Type;
-use type_of::LayoutLlvmExt;
-use value::Value;
 use rustc::ty::{self, Ty};
 use rustc_codegen_ssa::traits::*;
 
@@ -275,12 +275,12 @@ impl CodegenCx<'ll, 'tcx> {
                 self.use_dll_storage_attrs && !self.tcx.is_foreign_item(def_id) &&
                 // ThinLTO can't handle this workaround in all cases, so we don't
                 // emit the attrs. Instead we make them unnecessary by disallowing
-                // dynamic linking when cross-language LTO is enabled.
-                !self.tcx.sess.opts.debugging_opts.cross_lang_lto.enabled();
+                // dynamic linking when linker plugin based LTO is enabled.
+                !self.tcx.sess.opts.cg.linker_plugin_lto.enabled();
 
             // If this assertion triggers, there's something wrong with commandline
             // argument validation.
-            debug_assert!(!(self.tcx.sess.opts.debugging_opts.cross_lang_lto.enabled() &&
+            debug_assert!(!(self.tcx.sess.opts.cg.linker_plugin_lto.enabled() &&
                             self.tcx.sess.target.target.options.is_like_msvc &&
                             self.tcx.sess.opts.cg.prefer_dynamic));
 
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 2b03e99161db8..d9c4d22b41100 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -1,14 +1,14 @@
-use attributes;
-use llvm;
+use crate::attributes;
+use crate::llvm;
+use crate::debuginfo;
+use crate::monomorphize::Instance;
+use crate::value::Value;
 use rustc::dep_graph::DepGraphSafe;
 use rustc::hir;
-use debuginfo;
-use monomorphize::Instance;
-use value::Value;
 
-use monomorphize::partitioning::CodegenUnit;
-use type_::Type;
-use type_of::PointeeInfo;
+use crate::monomorphize::partitioning::CodegenUnit;
+use crate::type_::Type;
+use crate::type_of::PointeeInfo;
 use rustc_codegen_ssa::traits::*;
 use libc::c_uint;
 
@@ -23,7 +23,7 @@ use rustc::util::nodemap::FxHashMap;
 use rustc_target::spec::{HasTargetSpec, Target};
 use rustc_codegen_ssa::callee::resolve_and_get_fn;
 use rustc_codegen_ssa::base::wants_msvc_seh;
-use callee::get_fn;
+use crate::callee::get_fn;
 
 use std::ffi::CStr;
 use std::cell::{Cell, RefCell};
@@ -31,7 +31,7 @@ use std::iter;
 use std::str;
 use std::sync::Arc;
 use syntax::symbol::LocalInternedString;
-use abi::Abi;
+use crate::abi::Abi;
 
 /// There is one `CodegenCx` per compilation unit. Each one has its own LLVM
 /// `llvm::Context` so that several compilation units may be optimized in parallel.
@@ -75,7 +75,7 @@ pub struct CodegenCx<'ll, 'tcx: 'll> {
     pub statics_to_rauw: RefCell<Vec<(&'ll Value, &'ll Value)>>,
 
     /// Statics that will be placed in the llvm.used variable
-    /// See http://llvm.org/docs/LangRef.html#the-llvm-used-global-variable for details
+    /// See <http://llvm.org/docs/LangRef.html#the-llvm-used-global-variable> for details
     pub used_statics: RefCell<Vec<&'ll Value>>,
 
     pub lltypes: RefCell<FxHashMap<(Ty<'tcx>, Option<VariantIdx>), &'ll Type>>,
@@ -103,7 +103,7 @@ pub fn get_reloc_model(sess: &Session) -> llvm::RelocMode {
         None => &sess.target.target.options.relocation_model[..],
     };
 
-    match ::back::write::RELOC_MODEL_ARGS.iter().find(
+    match crate::back::write::RELOC_MODEL_ARGS.iter().find(
         |&&arg| arg.0 == reloc_model_arg) {
         Some(x) => x.1,
         _ => {
@@ -121,7 +121,7 @@ fn get_tls_model(sess: &Session) -> llvm::ThreadLocalMode {
         None => &sess.target.target.options.tls_model[..],
     };
 
-    match ::back::write::TLS_MODEL_ARGS.iter().find(
+    match crate::back::write::TLS_MODEL_ARGS.iter().find(
         |&&arg| arg.0 == tls_model_arg) {
         Some(x) => x.1,
         _ => {
@@ -144,16 +144,17 @@ pub fn is_pie_binary(sess: &Session) -> bool {
 }
 
 pub unsafe fn create_module(
-    sess: &Session,
+    tcx: TyCtxt,
     llcx: &'ll llvm::Context,
     mod_name: &str,
 ) -> &'ll llvm::Module {
+    let sess = tcx.sess;
     let mod_name = SmallCStr::new(mod_name);
     let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
 
     // Ensure the data-layout values hardcoded remain the defaults.
     if sess.target.target.options.is_builtin {
-        let tm = ::back::write::create_target_machine(sess, false);
+        let tm = crate::back::write::create_target_machine(tcx, false);
         llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, tm);
         llvm::LLVMRustDisposeTargetMachine(tm);
 
@@ -211,7 +212,7 @@ pub unsafe fn create_module(
 impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
     crate fn new(tcx: TyCtxt<'ll, 'tcx, 'tcx>,
                  codegen_unit: Arc<CodegenUnit<'tcx>>,
-                 llvm_module: &'ll ::ModuleLlvm)
+                 llvm_module: &'ll crate::ModuleLlvm)
                  -> Self {
         // An interesting part of Windows which MSVC forces our hand on (and
         // apparently MinGW didn't) is the usage of `dllimport` and `dllexport`
@@ -376,7 +377,7 @@ impl MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     // Returns a Value of the "eh_unwind_resume" lang item if one is defined,
     // otherwise declares it as an external function.
     fn eh_unwind_resume(&self) -> &'ll Value {
-        use attributes;
+        use crate::attributes;
         let unwresume = &self.eh_unwind_resume;
         if let Some(llfn) = unwresume.get() {
             return llfn;
@@ -464,6 +465,20 @@ impl CodegenCx<'b, 'tcx> {
         self.declare_intrinsic(key).unwrap_or_else(|| bug!("unknown intrinsic '{}'", key))
     }
 
+    fn insert_intrinsic(
+        &self, name: &'static str, args: Option<&[&'b llvm::Type]>, ret: &'b llvm::Type
+    ) -> &'b llvm::Value {
+        let fn_ty = if let Some(args) = args {
+            self.type_func(args, ret)
+        } else {
+            self.type_variadic_func(&[], ret)
+        };
+        let f = self.declare_cfn(name, fn_ty);
+        llvm::SetUnnamedAddr(f, false);
+        self.intrinsics.borrow_mut().insert(name, f.clone());
+        f
+    }
+
     fn declare_intrinsic(
         &self,
         key: &str
@@ -471,26 +486,17 @@ impl CodegenCx<'b, 'tcx> {
         macro_rules! ifn {
             ($name:expr, fn() -> $ret:expr) => (
                 if key == $name {
-                    let f = self.declare_cfn($name, self.type_func(&[], $ret));
-                    llvm::SetUnnamedAddr(f, false);
-                    self.intrinsics.borrow_mut().insert($name, f.clone());
-                    return Some(f);
+                    return Some(self.insert_intrinsic($name, Some(&[]), $ret));
                 }
             );
             ($name:expr, fn(...) -> $ret:expr) => (
                 if key == $name {
-                    let f = self.declare_cfn($name, self.type_variadic_func(&[], $ret));
-                    llvm::SetUnnamedAddr(f, false);
-                    self.intrinsics.borrow_mut().insert($name, f.clone());
-                    return Some(f);
+                    return Some(self.insert_intrinsic($name, None, $ret));
                 }
             );
             ($name:expr, fn($($arg:expr),*) -> $ret:expr) => (
                 if key == $name {
-                    let f = self.declare_cfn($name, self.type_func(&[$($arg),*], $ret));
-                    llvm::SetUnnamedAddr(f, false);
-                    self.intrinsics.borrow_mut().insert($name, f.clone());
-                    return Some(f);
+                    return Some(self.insert_intrinsic($name, Some(&[$($arg),*]), $ret));
                 }
             );
         }
@@ -756,6 +762,30 @@ impl CodegenCx<'b, 'tcx> {
         ifn!("llvm.umul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
         ifn!("llvm.umul.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct!{t_i128, i1});
 
+        ifn!("llvm.sadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.sadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.sadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.sadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.sadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.uadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.uadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.uadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.uadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.uadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.ssub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.ssub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.ssub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.ssub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.ssub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+        ifn!("llvm.usub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+        ifn!("llvm.usub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+        ifn!("llvm.usub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+        ifn!("llvm.usub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+        ifn!("llvm.usub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
         ifn!("llvm.lifetime.start", fn(t_i64,i8p) -> void);
         ifn!("llvm.lifetime.end", fn(t_i64, i8p) -> void);
 
@@ -782,7 +812,7 @@ impl CodegenCx<'b, 'tcx> {
 }
 
 impl<'b, 'tcx> CodegenCx<'b, 'tcx> {
-    /// Generate a new symbol name with the given prefix. This symbol name must
+    /// Generates a new symbol name with the given prefix. This symbol name must
     /// only be used for definitions with `internal` or `private` linkage.
     pub fn generate_local_symbol_name(&self, prefix: &str) -> String {
         let idx = self.local_gen_sym_counter.get();
diff --git a/src/librustc_codegen_llvm/debuginfo/create_scope_map.rs b/src/librustc_codegen_llvm/debuginfo/create_scope_map.rs
index dbd821865f95f..3ba05bf1b5c91 100644
--- a/src/librustc_codegen_llvm/debuginfo/create_scope_map.rs
+++ b/src/librustc_codegen_llvm/debuginfo/create_scope_map.rs
@@ -2,9 +2,9 @@ use rustc_codegen_ssa::debuginfo::{FunctionDebugContext, FunctionDebugContextDat
 use super::metadata::file_metadata;
 use super::utils::{DIB, span_start};
 
-use llvm;
-use llvm::debuginfo::{DIScope, DISubprogram};
-use common::CodegenCx;
+use crate::llvm;
+use crate::llvm::debuginfo::{DIScope, DISubprogram};
+use crate::common::CodegenCx;
 use rustc::mir::{Mir, SourceScope};
 
 use libc::c_uint;
@@ -16,7 +16,7 @@ use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 
 use syntax_pos::BytePos;
 
-/// Produce DIScope DIEs for each MIR Scope which has variables defined in it.
+/// Produces DIScope DIEs for each MIR Scope which has variables defined in it.
 /// If debuginfo is disabled, the returned vector is empty.
 pub fn create_mir_scopes(
     cx: &CodegenCx<'ll, '_>,
diff --git a/src/librustc_codegen_llvm/debuginfo/doc.rs b/src/librustc_codegen_llvm/debuginfo/doc.rs
index a4acc58eca953..cf18b995b61da 100644
--- a/src/librustc_codegen_llvm/debuginfo/doc.rs
+++ b/src/librustc_codegen_llvm/debuginfo/doc.rs
@@ -160,7 +160,7 @@
 //!
 //! This algorithm also provides a stable ID for types that are defined in one
 //! crate but instantiated from metadata within another crate. We just have to
-//! take care to always map crate and node IDs back to the original crate
+//! take care to always map crate and `NodeId`s back to the original crate
 //! context.
 //!
 //! As a side-effect these unique type IDs also help to solve a problem arising
@@ -170,7 +170,7 @@
 //! with different concrete substitutions for `'a`, and thus there will be N
 //! `Ty` instances for the type `Struct<'a>` even though it is not generic
 //! otherwise. Unfortunately this means that we cannot use `ty::type_id()` as
-//! cheap identifier for type metadata---we have done this in the past, but it
+//! cheap identifier for type metadata -- we have done this in the past, but it
 //! led to unnecessary metadata duplication in the best case and LLVM
 //! assertions in the worst. However, the unique type ID as described above
 //! *can* be used as identifier. Since it is comparatively expensive to
diff --git a/src/librustc_codegen_llvm/debuginfo/gdb.rs b/src/librustc_codegen_llvm/debuginfo/gdb.rs
index c883d6030951d..2555c92fb7c32 100644
--- a/src/librustc_codegen_llvm/debuginfo/gdb.rs
+++ b/src/librustc_codegen_llvm/debuginfo/gdb.rs
@@ -1,11 +1,11 @@
 // .debug_gdb_scripts binary section.
 
-use llvm;
+use crate::llvm;
 
-use common::CodegenCx;
-use builder::Builder;
+use crate::common::CodegenCx;
+use crate::builder::Builder;
+use crate::value::Value;
 use rustc::session::config::DebugInfo;
-use value::Value;
 use rustc_codegen_ssa::traits::*;
 
 use syntax::attr;
diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 6deedd0b5ea33..da9ff54b0626c 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -7,15 +7,16 @@ use super::utils::{debug_context, DIB, span_start,
 use super::namespace::mangled_name_of_instance;
 use super::type_names::compute_debuginfo_type_name;
 use super::{CrateDebugContext};
+use crate::abi;
+use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
-use abi;
-use value::Value;
 
-use llvm;
-use llvm::debuginfo::{DIArray, DIType, DIFile, DIScope, DIDescriptor,
-                      DICompositeType, DILexicalBlock, DIFlags};
-use llvm_util;
+use crate::llvm;
+use crate::llvm::debuginfo::{DIArray, DIType, DIFile, DIScope, DIDescriptor,
+                      DICompositeType, DILexicalBlock, DIFlags, DebugEmissionKind};
+use crate::llvm_util;
 
+use crate::common::CodegenCx;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc::hir::CodegenFnAttrFlags;
 use rustc::hir::def::CtorKind;
@@ -23,7 +24,6 @@ use rustc::hir::def_id::{DefId, CrateNum, LOCAL_CRATE};
 use rustc::ich::NodeIdHashingMode;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc::ty::Instance;
-use common::CodegenCx;
 use rustc::ty::{self, AdtKind, ParamEnv, Ty, TyCtxt};
 use rustc::ty::layout::{self, Align, Integer, IntegerExt, LayoutOf,
                         PrimitiveExt, Size, TyLayout};
@@ -846,6 +846,7 @@ pub fn compile_unit_metadata(tcx: TyCtxt,
     let producer = CString::new(producer).unwrap();
     let flags = "\0";
     let split_name = "\0";
+    let kind = DebugEmissionKind::from_generic(tcx.sess.opts.debuginfo);
 
     unsafe {
         let file_metadata = llvm::LLVMRustDIBuilderCreateFile(
@@ -859,7 +860,8 @@ pub fn compile_unit_metadata(tcx: TyCtxt,
             tcx.sess.opts.optimize != config::OptLevel::No,
             flags.as_ptr() as *const _,
             0,
-            split_name.as_ptr() as *const _);
+            split_name.as_ptr() as *const _,
+            kind);
 
         if tcx.sess.opts.debugging_opts.profile {
             let cu_desc_metadata = llvm::LLVMRustMetadataAsValue(debug_context.llcontext,
@@ -1164,7 +1166,10 @@ fn use_enum_fallback(cx: &CodegenCx) -> bool {
     // On MSVC we have to use the fallback mode, because LLVM doesn't
     // lower variant parts to PDB.
     return cx.sess().target.target.options.is_like_msvc
-        || llvm_util::get_major_version() < 7;
+        // LLVM version 7 did not release with an important bug fix;
+        // but the required patch is in the LLVM 8.  Rust LLVM reports
+        // 8 as well.
+        || llvm_util::get_major_version() < 8;
 }
 
 // Describes the members of an enum value: An enum is described as a union of
diff --git a/src/librustc_codegen_llvm/debuginfo/mod.rs b/src/librustc_codegen_llvm/debuginfo/mod.rs
index 2eab626ae8e6e..664ca2533878d 100644
--- a/src/librustc_codegen_llvm/debuginfo/mod.rs
+++ b/src/librustc_codegen_llvm/debuginfo/mod.rs
@@ -10,24 +10,24 @@ use self::type_names::compute_debuginfo_type_name;
 use self::metadata::{type_metadata, file_metadata, TypeMap};
 use self::source_loc::InternalDebugLocation::{self, UnknownLocation};
 
-use llvm;
-use llvm::debuginfo::{DIFile, DIType, DIScope, DIBuilder, DISubprogram, DIArray, DIFlags,
-    DILexicalBlock};
+use crate::llvm;
+use crate::llvm::debuginfo::{DIFile, DIType, DIScope, DIBuilder, DISubprogram, DIArray, DIFlags,
+    DISPFlags, DILexicalBlock};
 use rustc::hir::CodegenFnAttrFlags;
-use rustc::hir::def_id::{DefId, CrateNum};
+use rustc::hir::def_id::{DefId, CrateNum, LOCAL_CRATE};
 use rustc::ty::subst::{Substs, UnpackedKind};
 
-use abi::Abi;
-use common::CodegenCx;
-use builder::Builder;
-use monomorphize::Instance;
+use crate::abi::Abi;
+use crate::common::CodegenCx;
+use crate::builder::Builder;
+use crate::monomorphize::Instance;
+use crate::value::Value;
 use rustc::ty::{self, ParamEnv, Ty, InstanceDef};
 use rustc::mir;
 use rustc::session::config::{self, DebugInfo};
 use rustc::util::nodemap::{DefIdMap, FxHashMap, FxHashSet};
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_data_structures::indexed_vec::IndexVec;
-use value::Value;
 use rustc_codegen_ssa::debuginfo::{FunctionDebugContext, MirDebugScope, VariableAccess,
     VariableKind, FunctionDebugContextData};
 
@@ -102,7 +102,7 @@ impl<'a, 'tcx> CrateDebugContext<'a, 'tcx> {
     }
 }
 
-/// Create any deferred debug metadata nodes
+/// Creates any deferred debug metadata nodes
 pub fn finalize(cx: &CodegenCx) {
     if cx.dbg_cx.is_none() {
         return;
@@ -283,16 +283,14 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         let linkage_name = mangled_name_of_instance(self, instance);
 
         let scope_line = span_start(self, span).line;
-        let is_local_to_unit = is_node_local_to_unit(self, def_id);
 
         let function_name = CString::new(name).unwrap();
         let linkage_name = SmallCStr::new(&linkage_name.as_str());
 
         let mut flags = DIFlags::FlagPrototyped;
 
-        let local_id = self.tcx().hir().as_local_node_id(def_id);
-        if let Some((id, _, _)) = *self.sess().entry_fn.borrow() {
-            if local_id == Some(id) {
+        if let Some((id, _)) = self.tcx.entry_fn(LOCAL_CRATE) {
+            if id == def_id {
                 flags |= DIFlags::FlagMainSubprogram;
             }
         }
@@ -301,6 +299,14 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             flags |= DIFlags::FlagNoReturn;
         }
 
+        let mut spflags = DISPFlags::SPFlagDefinition;
+        if is_node_local_to_unit(self, def_id) {
+            spflags |= DISPFlags::SPFlagLocalToUnit;
+        }
+        if self.sess().opts.optimize != config::OptLevel::No {
+            spflags |= DISPFlags::SPFlagOptimized;
+        }
+
         let fn_metadata = unsafe {
             llvm::LLVMRustDIBuilderCreateFunction(
                 DIB(self),
@@ -310,11 +316,9 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 file_metadata,
                 loc.line as c_uint,
                 function_type_metadata,
-                is_local_to_unit,
-                true,
                 scope_line as c_uint,
                 flags,
-                self.sess().opts.optimize != config::OptLevel::No,
+                spflags,
                 llfn,
                 template_parameters,
                 None)
diff --git a/src/librustc_codegen_llvm/debuginfo/namespace.rs b/src/librustc_codegen_llvm/debuginfo/namespace.rs
index 36188b8fc4797..f7c377adf3529 100644
--- a/src/librustc_codegen_llvm/debuginfo/namespace.rs
+++ b/src/librustc_codegen_llvm/debuginfo/namespace.rs
@@ -2,14 +2,14 @@
 
 use super::metadata::{unknown_file_metadata, UNKNOWN_LINE_NUMBER};
 use super::utils::{DIB, debug_context};
-use monomorphize::Instance;
+use crate::monomorphize::Instance;
 use rustc::ty;
 
-use llvm;
-use llvm::debuginfo::DIScope;
+use crate::llvm;
+use crate::llvm::debuginfo::DIScope;
+use crate::common::CodegenCx;
 use rustc::hir::def_id::DefId;
 use rustc::hir::map::DefPathData;
-use common::CodegenCx;
 
 use rustc_data_structures::small_c_str::SmallCStr;
 
diff --git a/src/librustc_codegen_llvm/debuginfo/source_loc.rs b/src/librustc_codegen_llvm/debuginfo/source_loc.rs
index ccf56c11e735d..f7620e11c233d 100644
--- a/src/librustc_codegen_llvm/debuginfo/source_loc.rs
+++ b/src/librustc_codegen_llvm/debuginfo/source_loc.rs
@@ -4,9 +4,9 @@ use super::utils::{debug_context, span_start};
 use super::metadata::UNKNOWN_COLUMN_NUMBER;
 use rustc_codegen_ssa::debuginfo::FunctionDebugContext;
 
-use llvm;
-use llvm::debuginfo::DIScope;
-use builder::Builder;
+use crate::llvm;
+use crate::llvm::debuginfo::DIScope;
+use crate::builder::Builder;
 use rustc_codegen_ssa::traits::*;
 
 use libc::c_uint;
diff --git a/src/librustc_codegen_llvm/debuginfo/type_names.rs b/src/librustc_codegen_llvm/debuginfo/type_names.rs
index 32432f7e4ec10..1697bb7b52dbd 100644
--- a/src/librustc_codegen_llvm/debuginfo/type_names.rs
+++ b/src/librustc_codegen_llvm/debuginfo/type_names.rs
@@ -1,6 +1,6 @@
 // Type Names for Debug Info.
 
-use common::CodegenCx;
+use crate::common::CodegenCx;
 use rustc::hir::def_id::DefId;
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, Ty};
@@ -125,7 +125,7 @@ pub fn push_debuginfo_type_name<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
             }
 
             let abi = sig.abi();
-            if abi != ::abi::Abi::Rust {
+            if abi != crate::abi::Abi::Rust {
                 output.push_str("extern \"");
                 output.push_str(abi.name());
                 output.push_str("\" ");
diff --git a/src/librustc_codegen_llvm/debuginfo/utils.rs b/src/librustc_codegen_llvm/debuginfo/utils.rs
index 8b85df79d0484..e1b299df6c312 100644
--- a/src/librustc_codegen_llvm/debuginfo/utils.rs
+++ b/src/librustc_codegen_llvm/debuginfo/utils.rs
@@ -6,12 +6,12 @@ use super::namespace::item_namespace;
 use rustc::hir::def_id::DefId;
 use rustc::ty::DefIdTree;
 
-use llvm;
-use llvm::debuginfo::{DIScope, DIBuilder, DIDescriptor, DIArray};
-use common::{CodegenCx};
+use crate::llvm;
+use crate::llvm::debuginfo::{DIScope, DIBuilder, DIDescriptor, DIArray};
+use crate::common::{CodegenCx};
 use rustc_codegen_ssa::traits::*;
 
-use syntax_pos::{self, Span};
+use syntax_pos::Span;
 
 pub fn is_node_local_to_unit(cx: &CodegenCx, def_id: DefId) -> bool
 {
@@ -36,7 +36,7 @@ pub fn create_DIArray(
     };
 }
 
-/// Return syntax_pos::Loc corresponding to the beginning of the span
+/// Returns syntax_pos::Loc corresponding to the beginning of the span
 pub fn span_start(cx: &CodegenCx, span: Span) -> syntax_pos::Loc {
     cx.sess().source_map().lookup_char_pos(span.lo())
 }
diff --git a/src/librustc_codegen_llvm/declare.rs b/src/librustc_codegen_llvm/declare.rs
index aa2a0016b3e7a..3febcb019ce29 100644
--- a/src/librustc_codegen_llvm/declare.rs
+++ b/src/librustc_codegen_llvm/declare.rs
@@ -11,18 +11,18 @@
 //! * Use define_* family of methods when you might be defining the Value.
 //! * When in doubt, define.
 
-use llvm;
-use llvm::AttributePlace::Function;
+use crate::llvm;
+use crate::llvm::AttributePlace::Function;
+use crate::abi::{FnType, FnTypeExt};
+use crate::attributes;
+use crate::context::CodegenCx;
+use crate::type_::Type;
+use crate::value::Value;
 use rustc::ty::{self, PolyFnSig};
 use rustc::ty::layout::LayoutOf;
 use rustc::session::config::Sanitizer;
 use rustc_data_structures::small_c_str::SmallCStr;
-use abi::{FnType, FnTypeExt};
-use attributes;
-use context::CodegenCx;
-use type_::Type;
 use rustc_codegen_ssa::traits::*;
-use value::Value;
 
 /// Declare a function.
 ///
@@ -65,19 +65,8 @@ fn declare_raw_fn(
         }
     }
 
-    match cx.tcx.sess.opts.cg.opt_level.as_ref().map(String::as_ref) {
-        Some("s") => {
-            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
-        },
-        Some("z") => {
-            llvm::Attribute::MinSize.apply_llfn(Function, llfn);
-            llvm::Attribute::OptimizeForSize.apply_llfn(Function, llfn);
-        },
-        _ => {},
-    }
-
+    attributes::default_optimisation_attrs(cx.tcx.sess, llfn);
     attributes::non_lazy_bind(cx.sess(), llfn);
-
     llfn
 }
 
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index eeb6a64164e9c..3785e19af970f 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -1,26 +1,26 @@
 #![allow(non_upper_case_globals)]
 
-use attributes;
-use llvm;
-use llvm_util;
-use abi::{Abi, FnType, LlvmType, PassMode};
+use crate::attributes;
+use crate::llvm;
+use crate::llvm_util;
+use crate::abi::{Abi, FnType, LlvmType, PassMode};
+use crate::context::CodegenCx;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::builder::Builder;
+use crate::value::Value;
+use crate::va_arg::emit_va_arg;
 use rustc_codegen_ssa::MemFlags;
 use rustc_codegen_ssa::mir::place::PlaceRef;
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::glue;
 use rustc_codegen_ssa::base::{to_immediate, wants_msvc_seh, compare_simd_types};
-use context::CodegenCx;
-use type_::Type;
-use type_of::LayoutLlvmExt;
 use rustc::ty::{self, Ty};
 use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, Primitive};
-use rustc_codegen_ssa::common::TypeKind;
+use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
 use rustc::hir;
 use syntax::ast::{self, FloatTy};
 use syntax::symbol::Symbol;
-use builder::Builder;
-use value::Value;
-use va_arg::emit_va_arg;
 
 use rustc_codegen_ssa::traits::*;
 
@@ -28,7 +28,7 @@ use rustc::session::Session;
 use syntax_pos::Span;
 
 use std::cmp::Ordering;
-use std::iter;
+use std::{iter, i128, u128};
 
 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
     let llvm_name = match name {
@@ -192,8 +192,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
             "size_of_val" => {
                 let tp_ty = substs.type_at(0);
                 if let OperandValue::Pair(_, meta) = args[0].val {
-                    let (llsize, _) =
-                        glue::size_and_align_of_dst(self, tp_ty, Some(meta));
+                    let (llsize, _) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
                     llsize
                 } else {
                     self.const_usize(self.size_of(tp_ty).bytes())
@@ -206,8 +205,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
             "min_align_of_val" => {
                 let tp_ty = substs.type_at(0);
                 if let OperandValue::Pair(_, meta) = args[0].val {
-                    let (_, llalign) =
-                        glue::size_and_align_of_dst(self, tp_ty, Some(meta));
+                    let (_, llalign) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
                     llalign
                 } else {
                     self.const_usize(self.align_of(tp_ty).bytes())
@@ -342,7 +340,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
             "bitreverse" | "add_with_overflow" | "sub_with_overflow" |
             "mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
             "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" | "exact_div" |
-            "rotate_left" | "rotate_right" => {
+            "rotate_left" | "rotate_right" | "saturating_add" | "saturating_sub" => {
                 let ty = arg_tys[0];
                 match int_type_width_signed(ty, self) {
                     Some((width, signed)) =>
@@ -468,6 +466,44 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
                                     self.or(shift1, shift2)
                                 }
                             },
+                            "saturating_add" | "saturating_sub" => {
+                                let is_add = name == "saturating_add";
+                                let lhs = args[0].immediate();
+                                let rhs = args[1].immediate();
+                                if llvm_util::get_major_version() >= 8 {
+                                    let llvm_name = &format!("llvm.{}{}.sat.i{}",
+                                                             if signed { 's' } else { 'u' },
+                                                             if is_add { "add" } else { "sub" },
+                                                             width);
+                                    let llfn = self.get_intrinsic(llvm_name);
+                                    self.call(llfn, &[lhs, rhs], None)
+                                } else {
+                                    let llvm_name = &format!("llvm.{}{}.with.overflow.i{}",
+                                                             if signed { 's' } else { 'u' },
+                                                             if is_add { "add" } else { "sub" },
+                                                             width);
+                                    let llfn = self.get_intrinsic(llvm_name);
+                                    let pair = self.call(llfn, &[lhs, rhs], None);
+                                    let val = self.extract_value(pair, 0);
+                                    let overflow = self.extract_value(pair, 1);
+                                    let llty = self.type_ix(width);
+
+                                    let limit = if signed {
+                                        let limit_lo = self.const_uint_big(
+                                            llty, (i128::MIN >> (128 - width)) as u128);
+                                        let limit_hi = self.const_uint_big(
+                                            llty, (i128::MAX >> (128 - width)) as u128);
+                                        let neg = self.icmp(
+                                            IntPredicate::IntSLT, val, self.const_uint(llty, 0));
+                                        self.select(neg, limit_hi, limit_lo)
+                                    } else if is_add {
+                                        self.const_uint_big(llty, u128::MAX >> (128 - width))
+                                    } else {
+                                        self.const_uint(llty, 0)
+                                    };
+                                    self.select(overflow, limit, val)
+                                }
+                            },
                             _ => bug!(),
                         },
                     None => {
@@ -1167,6 +1203,52 @@ fn generic_simd_intrinsic(
         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
     }
 
+    if name == "simd_bitmask" {
+        // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
+        // vector mask and returns an unsigned integer containing the most
+        // significant bit (MSB) of each lane.
+        use rustc_target::abi::HasDataLayout;
+
+        // If the vector has less than 8 lanes, an u8 is returned with zeroed
+        // trailing bits.
+        let expected_int_bits = in_len.max(8);
+        match ret_ty.sty {
+           ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => (),
+            _ => return_error!(
+                "bitmask `{}`, expected `u{}`",
+                ret_ty, expected_int_bits
+            ),
+        }
+
+        // Integer vector <i{in_bitwidth} x in_len>:
+        let (i_xn, in_elem_bitwidth) = match in_elem.sty {
+            ty::Int(i) => (
+                args[0].immediate(),
+                i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits() as _)
+            ),
+            ty::Uint(i) => (
+                args[0].immediate(),
+                i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits() as _)
+            ),
+            _ => return_error!(
+                "vector argument `{}`'s element type `{}`, expected integer element type",
+                in_ty, in_elem
+            ),
+        };
+
+        // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
+        let shift_indices = vec![
+            bx.cx.const_int(bx.type_ix(in_elem_bitwidth as _), (in_elem_bitwidth - 1) as _); in_len
+        ];
+        let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
+        // Truncate vector to an <i1 x N>
+        let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len as _));
+        // Bitcast <i1 x N> to iN:
+        let i_ = bx.bitcast(i1xn, bx.type_ix(in_len as _));
+        // Zero-extend iN to the bitmask type:
+        return Ok(bx.zext(i_, bx.type_ix(expected_int_bits as _)));
+    }
+
     fn simd_simple_float_intrinsic(
         name: &str,
         in_elem: &::rustc::ty::TyS,
diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index 272f34b0b3f16..9219f42d69235 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -4,9 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
@@ -17,14 +15,15 @@
 #![allow(unused_attributes)]
 #![feature(libc)]
 #![feature(nll)]
-#![feature(quote)]
 #![feature(range_contains)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(optin_builtin_traits)]
 #![feature(concat_idents)]
 #![feature(link_args)]
 #![feature(static_nobundle)]
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
+#![allow(elided_lifetimes_in_paths)]
 
 use back::write::create_target_machine;
 use syntax_pos::symbol::Symbol;
@@ -33,16 +32,11 @@ extern crate flate2;
 #[macro_use] extern crate bitflags;
 extern crate libc;
 #[macro_use] extern crate rustc;
-extern crate jobserver;
-extern crate num_cpus;
 extern crate rustc_mir;
 extern crate rustc_allocator;
-extern crate rustc_apfloat;
 extern crate rustc_target;
 #[macro_use] extern crate rustc_data_structures;
-extern crate rustc_demangle;
 extern crate rustc_incremental;
-extern crate rustc_llvm;
 extern crate rustc_codegen_utils;
 extern crate rustc_codegen_ssa;
 extern crate rustc_fs_util;
@@ -52,12 +46,10 @@ extern crate rustc_fs_util;
 extern crate syntax_pos;
 extern crate rustc_errors as errors;
 extern crate serialize;
-extern crate cc; // Used to locate MSVC
 extern crate tempfile;
-extern crate memmap;
 
 use rustc_codegen_ssa::traits::*;
-use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig};
+use rustc_codegen_ssa::back::write::{CodegenContext, ModuleConfig, FatLTOInput};
 use rustc_codegen_ssa::back::lto::{SerializedModule, LtoModuleCodegen, ThinModule};
 use rustc_codegen_ssa::CompiledModule;
 use errors::{FatalError, Handler};
@@ -73,7 +65,7 @@ use rustc::dep_graph::DepGraph;
 use rustc::middle::allocator::AllocatorKind;
 use rustc::middle::cstore::{EncodedMetadata, MetadataLoader};
 use rustc::session::{Session, CompileIncomplete};
-use rustc::session::config::{OutputFilenames, OutputType, PrintRequest};
+use rustc::session::config::{OutputFilenames, OutputType, PrintRequest, OptLevel};
 use rustc::ty::{self, TyCtxt};
 use rustc::util::time_graph;
 use rustc::util::profiling::ProfileCategory;
@@ -122,8 +114,8 @@ mod va_arg;
 pub struct LlvmCodegenBackend(());
 
 impl ExtraBackendMethods for LlvmCodegenBackend {
-    fn new_metadata(&self, sess: &Session, mod_name: &str) -> ModuleLlvm {
-        ModuleLlvm::new(sess, mod_name)
+    fn new_metadata(&self, tcx: TyCtxt, mod_name: &str) -> ModuleLlvm {
+        ModuleLlvm::new(tcx, mod_name)
     }
     fn write_metadata<'b, 'gcx>(
         &self,
@@ -145,10 +137,11 @@ impl ExtraBackendMethods for LlvmCodegenBackend {
     fn target_machine_factory(
         &self,
         sess: &Session,
+        optlvl: OptLevel,
         find_features: bool
     ) -> Arc<dyn Fn() ->
         Result<&'static mut llvm::TargetMachine, String> + Send + Sync> {
-        back::write::target_machine_factory(sess, find_features)
+        back::write::target_machine_factory(sess, optlvl, find_features)
     }
     fn target_cpu<'b>(&self, sess: &'b Session) -> &'b str {
         llvm_util::target_cpu(sess)
@@ -167,10 +160,11 @@ impl WriteBackendMethods for LlvmCodegenBackend {
     }
     fn run_fat_lto(
         cgcx: &CodegenContext<Self>,
-        modules: Vec<ModuleCodegen<Self::Module>>,
+        modules: Vec<FatLTOInput<Self>>,
+        cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
         timeline: &mut Timeline
     ) -> Result<LtoModuleCodegen<Self>, FatalError> {
-        back::lto::run_fat(cgcx, modules, timeline)
+        back::lto::run_fat(cgcx, modules, cached_modules, timeline)
     }
     fn run_thin_lto(
         cgcx: &CodegenContext<Self>,
@@ -206,10 +200,14 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         back::write::codegen(cgcx, diag_handler, module, config, timeline)
     }
     fn prepare_thin(
-        cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>
     ) -> (String, Self::ThinBuffer) {
-        back::lto::prepare_thin(cgcx, module)
+        back::lto::prepare_thin(module)
+    }
+    fn serialize_module(
+        module: ModuleCodegen<Self::Module>
+    ) -> (String, Self::ModuleBuffer) {
+        (module.name, back::lto::ModuleBuffer::new(module.module_llvm.llmod()))
     }
     fn run_lto_pass_manager(
         cgcx: &CodegenContext<Self>,
@@ -364,19 +362,44 @@ unsafe impl Send for ModuleLlvm { }
 unsafe impl Sync for ModuleLlvm { }
 
 impl ModuleLlvm {
-    fn new(sess: &Session, mod_name: &str) -> Self {
+    fn new(tcx: TyCtxt, mod_name: &str) -> Self {
         unsafe {
-            let llcx = llvm::LLVMRustContextCreate(sess.fewer_names());
-            let llmod_raw = context::create_module(sess, llcx, mod_name) as *const _;
+            let llcx = llvm::LLVMRustContextCreate(tcx.sess.fewer_names());
+            let llmod_raw = context::create_module(tcx, llcx, mod_name) as *const _;
 
             ModuleLlvm {
                 llmod_raw,
                 llcx,
-                tm: create_target_machine(sess, false),
+                tm: create_target_machine(tcx, false),
             }
         }
     }
 
+    fn parse(
+        cgcx: &CodegenContext<LlvmCodegenBackend>,
+        name: &str,
+        buffer: &back::lto::ModuleBuffer,
+        handler: &Handler,
+    ) -> Result<Self, FatalError> {
+        unsafe {
+            let llcx = llvm::LLVMRustContextCreate(cgcx.fewer_names);
+            let llmod_raw = buffer.parse(name, llcx, handler)?;
+            let tm = match (cgcx.tm_factory.0)() {
+                Ok(m) => m,
+                Err(e) => {
+                    handler.struct_err(&e).emit();
+                    return Err(FatalError)
+                }
+            };
+
+            Ok(ModuleLlvm {
+                llmod_raw,
+                llcx,
+                tm,
+            })
+        }
+    }
+
     fn llmod(&self) -> &llvm::Module {
         unsafe {
             &*self.llmod_raw
diff --git a/src/librustc_codegen_llvm/llvm/diagnostic.rs b/src/librustc_codegen_llvm/llvm/diagnostic.rs
index 0f5d28f9fec5e..a8d272f157ce3 100644
--- a/src/librustc_codegen_llvm/llvm/diagnostic.rs
+++ b/src/librustc_codegen_llvm/llvm/diagnostic.rs
@@ -4,7 +4,7 @@ pub use self::OptimizationDiagnosticKind::*;
 pub use self::Diagnostic::*;
 
 use libc::c_uint;
-use value::Value;
+use crate::value::Value;
 
 use super::{DiagnosticInfo, Twine};
 
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index 11e34f600c286..e761d2247a757 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -2,15 +2,13 @@ use super::debuginfo::{
     DIBuilder, DIDescriptor, DIFile, DILexicalBlock, DISubprogram, DIType,
     DIBasicType, DIDerivedType, DICompositeType, DIScope, DIVariable,
     DIGlobalVariableExpression, DIArray, DISubrange, DITemplateTypeParameter, DIEnumerator,
-    DINameSpace, DIFlags,
+    DINameSpace, DIFlags, DISPFlags, DebugEmissionKind,
 };
 
 use libc::{c_uint, c_int, size_t, c_char};
 use libc::{c_ulonglong, c_void};
 
 use std::marker::PhantomData;
-use syntax;
-use rustc_codegen_ssa;
 
 use super::RustString;
 
@@ -115,6 +113,7 @@ pub enum Attribute {
     SanitizeAddress = 21,
     SanitizeMemory  = 22,
     NonLazyBind     = 23,
+    OptimizeNone    = 24,
 }
 
 /// LLVMIntPredicate
@@ -591,6 +590,40 @@ pub mod debuginfo {
             const FlagMainSubprogram      = (1 << 21);
         }
     }
+
+    // These values **must** match with LLVMRustDISPFlags!!
+    bitflags! {
+        #[repr(C)]
+        #[derive(Default)]
+        pub struct DISPFlags: ::libc::uint32_t {
+            const SPFlagZero              = 0;
+            const SPFlagVirtual           = 1;
+            const SPFlagPureVirtual       = 2;
+            const SPFlagLocalToUnit       = (1 << 2);
+            const SPFlagDefinition        = (1 << 3);
+            const SPFlagOptimized         = (1 << 4);
+        }
+    }
+
+    /// LLVMRustDebugEmissionKind
+    #[derive(Copy, Clone)]
+    #[repr(C)]
+    pub enum DebugEmissionKind {
+        NoDebug,
+        FullDebug,
+        LineTablesOnly,
+    }
+
+    impl DebugEmissionKind {
+        pub fn from_generic(kind: rustc::session::config::DebugInfo) -> Self {
+            use rustc::session::config::DebugInfo;
+            match kind {
+                DebugInfo::None => DebugEmissionKind::NoDebug,
+                DebugInfo::Limited => DebugEmissionKind::LineTablesOnly,
+                DebugInfo::Full => DebugEmissionKind::FullDebug,
+            }
+        }
+    }
 }
 
 extern { pub type ModuleBuffer; }
@@ -1302,7 +1335,7 @@ extern "C" {
     pub fn LLVMGetSections(ObjFile: &'a ObjectFile) -> &'a mut SectionIterator<'a>;
     /// Destroys a section iterator.
     pub fn LLVMDisposeSectionIterator(SI: &'a mut SectionIterator<'a>);
-    /// Returns true if the section iterator is at the end of the section
+    /// Returns `true` if the section iterator is at the end of the section
     /// list:
     pub fn LLVMIsSectionIteratorAtEnd(ObjFile: &'a ObjectFile, SI: &SectionIterator<'a>) -> Bool;
     /// Moves the section iterator to point to the next section.
@@ -1367,7 +1400,8 @@ extern "C" {
                                               isOptimized: bool,
                                               Flags: *const c_char,
                                               RuntimeVer: c_uint,
-                                              SplitName: *const c_char)
+                                              SplitName: *const c_char,
+                                              kind: DebugEmissionKind)
                                               -> &'a DIDescriptor;
 
     pub fn LLVMRustDIBuilderCreateFile(Builder: &DIBuilder<'a>,
@@ -1387,11 +1421,9 @@ extern "C" {
                                            File: &'a DIFile,
                                            LineNo: c_uint,
                                            Ty: &'a DIType,
-                                           isLocalToUnit: bool,
-                                           isDefinition: bool,
                                            ScopeLine: c_uint,
                                            Flags: DIFlags,
-                                           isOptimized: bool,
+                                           SPFlags: DISPFlags,
                                            Fn: &'a Value,
                                            TParam: &'a DIArray,
                                            Decl: Option<&'a DIDescriptor>)
@@ -1529,7 +1561,7 @@ extern "C" {
                                                   AlignInBits: u32,
                                                   Elements: &'a DIArray,
                                                   ClassType: &'a DIType,
-                                                  IsFixed: bool)
+                                                  IsScoped: bool)
                                                   -> &'a DIType;
 
     pub fn LLVMRustDIBuilderCreateUnionType(Builder: &DIBuilder<'a>,
@@ -1770,7 +1802,7 @@ extern "C" {
         CallbackPayload: *mut c_void,
     );
     pub fn LLVMRustFreeThinLTOData(Data: &'static mut ThinLTOData);
-    pub fn LLVMRustParseBitcodeForThinLTO(
+    pub fn LLVMRustParseBitcodeForLTO(
         Context: &Context,
         Data: *const u8,
         len: usize,
diff --git a/src/librustc_codegen_llvm/llvm/mod.rs b/src/librustc_codegen_llvm/llvm/mod.rs
index 6a596d78da285..543cc912930fd 100644
--- a/src/librustc_codegen_llvm/llvm/mod.rs
+++ b/src/librustc_codegen_llvm/llvm/mod.rs
@@ -16,7 +16,7 @@ use std::string::FromUtf8Error;
 use std::slice;
 use std::ffi::CStr;
 use std::cell::RefCell;
-use libc::{self, c_uint, c_char, size_t};
+use libc::{c_uint, c_char, size_t};
 use rustc_data_structures::small_c_str::SmallCStr;
 
 pub mod archive_ro;
diff --git a/src/librustc_codegen_llvm/llvm_util.rs b/src/librustc_codegen_llvm/llvm_util.rs
index ad9ebbcde8ab9..5fea9c8747e0f 100644
--- a/src/librustc_codegen_llvm/llvm_util.rs
+++ b/src/librustc_codegen_llvm/llvm_util.rs
@@ -1,8 +1,9 @@
+use crate::back::write::create_informational_target_machine;
+use crate::llvm;
 use syntax_pos::symbol::Symbol;
-use back::write::create_target_machine;
-use llvm;
 use rustc::session::Session;
 use rustc::session::config::PrintRequest;
+use rustc_target::spec::MergeFunctions;
 use libc::c_int;
 use std::ffi::CString;
 use syntax::feature_gate::UnstableFeatures;
@@ -61,7 +62,14 @@ unsafe fn configure_llvm(sess: &Session) {
             add("-disable-preinline");
         }
         if llvm::LLVMRustIsRustLLVM() {
-            add("-mergefunc-use-aliases");
+            match sess.opts.debugging_opts.merge_functions
+                  .unwrap_or(sess.target.target.options.merge_functions) {
+                MergeFunctions::Disabled |
+                MergeFunctions::Trampolines => {}
+                MergeFunctions::Aliases => {
+                    add("-mergefunc-use-aliases");
+                }
+            }
         }
 
         // HACK(eddyb) LLVM inserts `llvm.assume` calls to preserve align attributes
@@ -92,9 +100,11 @@ const ARM_WHITELIST: &[(&str, Option<&str>)] = &[
     ("dsp", Some("arm_target_feature")),
     ("neon", Some("arm_target_feature")),
     ("v5te", Some("arm_target_feature")),
+    ("v6", Some("arm_target_feature")),
     ("v6k", Some("arm_target_feature")),
     ("v6t2", Some("arm_target_feature")),
     ("v7", Some("arm_target_feature")),
+    ("v8", Some("arm_target_feature")),
     ("vfp2", Some("arm_target_feature")),
     ("vfp3", Some("arm_target_feature")),
     ("vfp4", Some("arm_target_feature")),
@@ -139,6 +149,7 @@ const X86_WHITELIST: &[(&str, Option<&str>)] = &[
     ("fxsr", None),
     ("lzcnt", None),
     ("mmx", Some("mmx_target_feature")),
+    ("movbe", Some("movbe_target_feature")),
     ("pclmulqdq", None),
     ("popcnt", None),
     ("rdrand", None),
@@ -215,7 +226,7 @@ pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
 }
 
 pub fn target_features(sess: &Session) -> Vec<Symbol> {
-    let target_machine = create_target_machine(sess, true);
+    let target_machine = create_informational_target_machine(sess, true);
     target_feature_whitelist(sess)
         .iter()
         .filter_map(|&(feature, gate)| {
@@ -268,7 +279,7 @@ pub fn print_passes() {
 
 pub(crate) fn print(req: PrintRequest, sess: &Session) {
     require_inited();
-    let tm = create_target_machine(sess, true);
+    let tm = create_informational_target_machine(sess, true);
     unsafe {
         match req {
             PrintRequest::TargetCPUs => llvm::LLVMRustPrintTargetCPUs(tm),
diff --git a/src/librustc_codegen_llvm/metadata.rs b/src/librustc_codegen_llvm/metadata.rs
index 6e77768b558d4..a2df687d58f5a 100644
--- a/src/librustc_codegen_llvm/metadata.rs
+++ b/src/librustc_codegen_llvm/metadata.rs
@@ -1,8 +1,8 @@
+use crate::llvm;
+use crate::llvm::{False, ObjectFile, mk_section_iter};
+use crate::llvm::archive_ro::ArchiveRO;
 use rustc::middle::cstore::MetadataLoader;
 use rustc_target::spec::Target;
-use llvm;
-use llvm::{False, ObjectFile, mk_section_iter};
-use llvm::archive_ro::ArchiveRO;
 
 use rustc_data_structures::owning_ref::OwningRef;
 use std::path::Path;
diff --git a/src/librustc_codegen_llvm/mono_item.rs b/src/librustc_codegen_llvm/mono_item.rs
index 69fc8783dc8d2..4fe6a1f4f4b1c 100644
--- a/src/librustc_codegen_llvm/mono_item.rs
+++ b/src/librustc_codegen_llvm/mono_item.rs
@@ -1,9 +1,9 @@
-use attributes;
-use base;
-use context::CodegenCx;
-use llvm;
-use monomorphize::Instance;
-use type_of::LayoutLlvmExt;
+use crate::attributes;
+use crate::base;
+use crate::context::CodegenCx;
+use crate::llvm;
+use crate::monomorphize::Instance;
+use crate::type_of::LayoutLlvmExt;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::mir::mono::{Linkage, Visibility};
 use rustc::ty::TypeFoldable;
diff --git a/src/librustc_codegen_llvm/type_.rs b/src/librustc_codegen_llvm/type_.rs
index 958e00506d62a..ca61987e12f7a 100644
--- a/src/librustc_codegen_llvm/type_.rs
+++ b/src/librustc_codegen_llvm/type_.rs
@@ -1,22 +1,22 @@
 #![allow(non_upper_case_globals)]
 
-pub use llvm::Type;
+pub use crate::llvm::Type;
 
-use llvm;
-use llvm::{Bool, False, True};
-use context::CodegenCx;
+use crate::llvm;
+use crate::llvm::{Bool, False, True};
+use crate::context::CodegenCx;
+use crate::value::Value;
 use rustc_codegen_ssa::traits::*;
-use value::Value;
 
+use crate::common;
+use crate::type_of::LayoutLlvmExt;
+use crate::abi::{LlvmType, FnTypeExt};
 use rustc::util::nodemap::FxHashMap;
 use rustc::ty::Ty;
 use rustc::ty::layout::TyLayout;
 use rustc_target::abi::call::{CastTarget, FnType, Reg};
 use rustc_data_structures::small_c_str::SmallCStr;
-use common;
 use rustc_codegen_ssa::common::TypeKind;
-use type_of::LayoutLlvmExt;
-use abi::{LlvmType, FnTypeExt};
 
 use std::fmt;
 use std::cell::RefCell;
@@ -82,7 +82,6 @@ impl BaseTypeMethods<'tcx> for CodegenCx<'ll, 'tcx> {
 
     fn type_i16(&self) -> &'ll Type {
         unsafe {
-
             llvm::LLVMInt16TypeInContext(self.llcx)
         }
     }
diff --git a/src/librustc_codegen_llvm/type_of.rs b/src/librustc_codegen_llvm/type_of.rs
index 97128c2d2a2ce..fb5624d56078e 100644
--- a/src/librustc_codegen_llvm/type_of.rs
+++ b/src/librustc_codegen_llvm/type_of.rs
@@ -1,12 +1,12 @@
-use abi::{FnType, FnTypeExt};
-use common::*;
+use crate::abi::{FnType, FnTypeExt};
+use crate::common::*;
+use crate::type_::Type;
 use rustc::hir;
 use rustc::ty::{self, Ty, TypeFoldable};
 use rustc::ty::layout::{self, Align, LayoutOf, Size, TyLayout};
 use rustc_target::abi::FloatTy;
 use rustc_mir::monomorphize::item::DefPathBasedNames;
 use rustc_codegen_ssa::traits::*;
-use type_::Type;
 
 use std::fmt::Write;
 
@@ -55,7 +55,7 @@ fn uncached_llvm_type<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
         ty::Str => {
             let mut name = String::with_capacity(32);
             let printer = DefPathBasedNames::new(cx.tcx, true, true);
-            printer.push_type_name(layout.ty, &mut name);
+            printer.push_type_name(layout.ty, &mut name, false);
             if let (&ty::Adt(def, _), &layout::Variants::Single { index })
                  = (&layout.ty.sty, &layout.variants)
             {
@@ -226,7 +226,7 @@ impl<'tcx> LayoutLlvmExt<'tcx> for TyLayout<'tcx> {
         }
     }
 
-    /// Get the LLVM type corresponding to a Rust type, i.e., `rustc::ty::Ty`.
+    /// Gets the LLVM type corresponding to a Rust type, i.e., `rustc::ty::Ty`.
     /// The pointee type of the pointer in `PlaceRef` is always this type.
     /// For sized types, it is also the right LLVM type for an `alloca`
     /// containing a value of that type, and most immediates (except `bool`).
diff --git a/src/librustc_codegen_llvm/va_arg.rs b/src/librustc_codegen_llvm/va_arg.rs
index 9239f85a8f230..8719390b51aca 100644
--- a/src/librustc_codegen_llvm/va_arg.rs
+++ b/src/librustc_codegen_llvm/va_arg.rs
@@ -1,11 +1,11 @@
-use builder::Builder;
+use crate::builder::Builder;
+use crate::type_::Type;
+use crate::type_of::LayoutLlvmExt;
+use crate::value::Value;
 use rustc_codegen_ssa::mir::operand::OperandRef;
 use rustc_codegen_ssa::traits::{BaseTypeMethods, BuilderMethods, ConstMethods, DerivedTypeMethods};
 use rustc::ty::layout::{Align, HasDataLayout, HasTyCtxt, LayoutOf, Size};
 use rustc::ty::Ty;
-use type_::Type;
-use type_of::LayoutLlvmExt;
-use value::Value;
 
 #[allow(dead_code)]
 fn round_pointer_up_to_alignment(
diff --git a/src/librustc_codegen_llvm/value.rs b/src/librustc_codegen_llvm/value.rs
index 3ad1521be9393..68809284bb726 100644
--- a/src/librustc_codegen_llvm/value.rs
+++ b/src/librustc_codegen_llvm/value.rs
@@ -1,6 +1,6 @@
-pub use llvm::Value;
+pub use crate::llvm::Value;
 
-use llvm;
+use crate::llvm;
 
 use std::fmt;
 use std::hash::{Hash, Hasher};
diff --git a/src/librustc_codegen_ssa/Cargo.toml b/src/librustc_codegen_ssa/Cargo.toml
index 50994497c2843..0aba43580f1f6 100644
--- a/src/librustc_codegen_ssa/Cargo.toml
+++ b/src/librustc_codegen_ssa/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_codegen_ssa"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_codegen_ssa"
diff --git a/src/librustc_codegen_ssa/back/link.rs b/src/librustc_codegen_ssa/back/link.rs
index d03bb0a3d73a4..7f1aebace8fc6 100644
--- a/src/librustc_codegen_ssa/back/link.rs
+++ b/src/librustc_codegen_ssa/back/link.rs
@@ -9,7 +9,7 @@ use rustc_target::spec::LinkerFlavor;
 use rustc::hir::def_id::CrateNum;
 
 use super::command::Command;
-use CrateInfo;
+use crate::CrateInfo;
 
 use cc::windows_registry;
 use std::fs;
@@ -149,6 +149,7 @@ pub fn linker_and_flavor(sess: &Session) -> (PathBuf, LinkerFlavor) {
                 LinkerFlavor::Ld => "ld",
                 LinkerFlavor::Msvc => "link.exe",
                 LinkerFlavor::Lld(_) => "lld",
+                LinkerFlavor::PtxLinker => "rust-ptx-linker",
             }), flavor)),
             (Some(linker), None) => {
                 let stem = if linker.extension().and_then(|ext| ext.to_str()) == Some("exe") {
diff --git a/src/librustc_codegen_ssa/back/linker.rs b/src/librustc_codegen_ssa/back/linker.rs
index 06d4f940436da..356bb8d50ad0d 100644
--- a/src/librustc_codegen_ssa/back/linker.rs
+++ b/src/librustc_codegen_ssa/back/linker.rs
@@ -13,7 +13,7 @@ use rustc::hir::def_id::{LOCAL_CRATE, CrateNum};
 use rustc::middle::dependency_format::Linkage;
 use rustc::session::Session;
 use rustc::session::config::{self, CrateType, OptLevel, DebugInfo,
-                             CrossLangLto};
+                             LinkerPluginLto, Lto};
 use rustc::ty::TyCtxt;
 use rustc_target::spec::{LinkerFlavor, LldFlavor};
 use serialize::{json, Encoder};
@@ -83,11 +83,15 @@ impl LinkerInfo {
             LinkerFlavor::Lld(LldFlavor::Wasm) => {
                 Box::new(WasmLd::new(cmd, sess, self)) as Box<dyn Linker>
             }
+
+            LinkerFlavor::PtxLinker => {
+                Box::new(PtxLinker { cmd, sess }) as Box<dyn Linker>
+            }
         }
     }
 }
 
-/// Linker abstraction used by back::link to build up the command to invoke a
+/// Linker abstraction used by `back::link` to build up the command to invoke a
 /// linker.
 ///
 /// This trait is the total list of requirements needed by `back::link` and
@@ -123,7 +127,7 @@ pub trait Linker {
     fn subsystem(&mut self, subsystem: &str);
     fn group_start(&mut self);
     fn group_end(&mut self);
-    fn cross_lang_lto(&mut self);
+    fn linker_plugin_lto(&mut self);
     // Should have been finalize(self), but we don't support self-by-value on trait objects (yet?).
     fn finalize(&mut self) -> Command;
 }
@@ -141,7 +145,7 @@ pub struct GccLinker<'a> {
 impl<'a> GccLinker<'a> {
     /// Argument that must be passed *directly* to the linker
     ///
-    /// These arguments need to be prepended with '-Wl,' when a gcc-style linker is used
+    /// These arguments need to be prepended with `-Wl`, when a GCC-style linker is used.
     fn linker_arg<S>(&mut self, arg: S) -> &mut Self
         where S: AsRef<OsStr>
     {
@@ -179,7 +183,7 @@ impl<'a> GccLinker<'a> {
         }
     }
 
-    fn push_cross_lang_lto_args(&mut self, plugin_path: Option<&OsStr>) {
+    fn push_linker_plugin_lto_args(&mut self, plugin_path: Option<&OsStr>) {
         if let Some(plugin_path) = plugin_path {
             let mut arg = OsString::from("-plugin=");
             arg.push(plugin_path);
@@ -450,16 +454,16 @@ impl<'a> Linker for GccLinker<'a> {
         }
     }
 
-    fn cross_lang_lto(&mut self) {
-        match self.sess.opts.debugging_opts.cross_lang_lto {
-            CrossLangLto::Disabled => {
+    fn linker_plugin_lto(&mut self) {
+        match self.sess.opts.cg.linker_plugin_lto {
+            LinkerPluginLto::Disabled => {
                 // Nothing to do
             }
-            CrossLangLto::LinkerPluginAuto => {
-                self.push_cross_lang_lto_args(None);
+            LinkerPluginLto::LinkerPluginAuto => {
+                self.push_linker_plugin_lto_args(None);
             }
-            CrossLangLto::LinkerPlugin(ref path) => {
-                self.push_cross_lang_lto_args(Some(path.as_os_str()));
+            LinkerPluginLto::LinkerPlugin(ref path) => {
+                self.push_linker_plugin_lto_args(Some(path.as_os_str()));
             }
         }
     }
@@ -693,7 +697,7 @@ impl<'a> Linker for MsvcLinker<'a> {
     fn group_start(&mut self) {}
     fn group_end(&mut self) {}
 
-    fn cross_lang_lto(&mut self) {
+    fn linker_plugin_lto(&mut self) {
         // Do nothing
     }
 }
@@ -861,7 +865,7 @@ impl<'a> Linker for EmLinker<'a> {
     fn group_start(&mut self) {}
     fn group_end(&mut self) {}
 
-    fn cross_lang_lto(&mut self) {
+    fn linker_plugin_lto(&mut self) {
         // Do nothing
     }
 }
@@ -911,9 +915,6 @@ impl<'a> WasmLd<'a> {
         // For now we just never have an entry symbol
         cmd.arg("--no-entry");
 
-        // Make the default table accessible
-        cmd.arg("--export-table");
-
         // Rust code should never have warnings, and warnings are often
         // indicative of bugs, let's prevent them.
         cmd.arg("--fatal-warnings");
@@ -1046,7 +1047,7 @@ impl<'a> Linker for WasmLd<'a> {
     fn group_start(&mut self) {}
     fn group_end(&mut self) {}
 
-    fn cross_lang_lto(&mut self) {
+    fn linker_plugin_lto(&mut self) {
         // Do nothing for now
     }
 }
@@ -1083,3 +1084,129 @@ fn exported_symbols(tcx: TyCtxt, crate_type: CrateType) -> Vec<String> {
 
     symbols
 }
+
+/// Much simplified and explicit CLI for the NVPTX linker. The linker operates
+/// with bitcode and uses LLVM backend to generate a PTX assembly.
+pub struct PtxLinker<'a> {
+    cmd: Command,
+    sess: &'a Session,
+}
+
+impl<'a> Linker for PtxLinker<'a> {
+    fn link_rlib(&mut self, path: &Path) {
+        self.cmd.arg("--rlib").arg(path);
+    }
+
+    fn link_whole_rlib(&mut self, path: &Path) {
+        self.cmd.arg("--rlib").arg(path);
+    }
+
+    fn include_path(&mut self, path: &Path) {
+        self.cmd.arg("-L").arg(path);
+    }
+
+    fn debuginfo(&mut self) {
+        self.cmd.arg("--debug");
+    }
+
+    fn add_object(&mut self, path: &Path) {
+        self.cmd.arg("--bitcode").arg(path);
+    }
+
+    fn args(&mut self, args: &[String]) {
+        self.cmd.args(args);
+    }
+
+    fn optimize(&mut self) {
+        match self.sess.lto() {
+            Lto::Thin | Lto::Fat | Lto::ThinLocal => {
+                self.cmd.arg("-Olto");
+            },
+
+            Lto::No => { },
+        };
+    }
+
+    fn output_filename(&mut self, path: &Path) {
+        self.cmd.arg("-o").arg(path);
+    }
+
+    fn finalize(&mut self) -> Command {
+        // Provide the linker with fallback to internal `target-cpu`.
+        self.cmd.arg("--fallback-arch").arg(match self.sess.opts.cg.target_cpu {
+            Some(ref s) => s,
+            None => &self.sess.target.target.options.cpu
+        });
+
+        ::std::mem::replace(&mut self.cmd, Command::new(""))
+    }
+
+    fn link_dylib(&mut self, _lib: &str) {
+        panic!("external dylibs not supported")
+    }
+
+    fn link_rust_dylib(&mut self, _lib: &str, _path: &Path) {
+        panic!("external dylibs not supported")
+    }
+
+    fn link_staticlib(&mut self, _lib: &str) {
+        panic!("staticlibs not supported")
+    }
+
+    fn link_whole_staticlib(&mut self, _lib: &str, _search_path: &[PathBuf]) {
+        panic!("staticlibs not supported")
+    }
+
+    fn framework_path(&mut self, _path: &Path) {
+        panic!("frameworks not supported")
+    }
+
+    fn link_framework(&mut self, _framework: &str) {
+        panic!("frameworks not supported")
+    }
+
+    fn position_independent_executable(&mut self) {
+    }
+
+    fn full_relro(&mut self) {
+    }
+
+    fn partial_relro(&mut self) {
+    }
+
+    fn no_relro(&mut self) {
+    }
+
+    fn build_static_executable(&mut self) {
+    }
+
+    fn gc_sections(&mut self, _keep_metadata: bool) {
+    }
+
+    fn pgo_gen(&mut self) {
+    }
+
+    fn no_default_libraries(&mut self) {
+    }
+
+    fn build_dylib(&mut self, _out_filename: &Path) {
+    }
+
+    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType) {
+    }
+
+    fn subsystem(&mut self, _subsystem: &str) {
+    }
+
+    fn no_position_independent_executable(&mut self) {
+    }
+
+    fn group_start(&mut self) {
+    }
+
+    fn group_end(&mut self) {
+    }
+
+    fn linker_plugin_lto(&mut self) {
+    }
+}
diff --git a/src/librustc_codegen_ssa/back/lto.rs b/src/librustc_codegen_ssa/back/lto.rs
index f0fb115f91b94..7f0eba7b0850b 100644
--- a/src/librustc_codegen_ssa/back/lto.rs
+++ b/src/librustc_codegen_ssa/back/lto.rs
@@ -1,6 +1,6 @@
 use super::write::CodegenContext;
-use traits::*;
-use ModuleCodegen;
+use crate::traits::*;
+use crate::ModuleCodegen;
 
 use rustc::util::time_graph::Timeline;
 use rustc_errors::FatalError;
diff --git a/src/librustc_codegen_ssa/back/symbol_export.rs b/src/librustc_codegen_ssa/back/symbol_export.rs
index bf69089a254a4..c372892c521be 100644
--- a/src/librustc_codegen_ssa/back/symbol_export.rs
+++ b/src/librustc_codegen_ssa/back/symbol_export.rs
@@ -194,7 +194,7 @@ fn exported_symbols_provider_local<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                  })
                                  .collect();
 
-    if tcx.sess.entry_fn.borrow().is_some() {
+    if tcx.entry_fn(LOCAL_CRATE).is_some() {
         let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new("main"));
 
         symbols.push((exported_symbol, SymbolExportLevel::C));
diff --git a/src/librustc_codegen_ssa/back/write.rs b/src/librustc_codegen_ssa/back/write.rs
index fb3e7ea696363..20842553c2666 100644
--- a/src/librustc_codegen_ssa/back/write.rs
+++ b/src/librustc_codegen_ssa/back/write.rs
@@ -1,12 +1,12 @@
-use {ModuleCodegen, ModuleKind, CachedModuleCodegen, CompiledModule, CrateInfo, CodegenResults,
-    RLIB_BYTECODE_EXTENSION};
+use crate::{ModuleCodegen, ModuleKind, CachedModuleCodegen, CompiledModule, CrateInfo,
+    CodegenResults, RLIB_BYTECODE_EXTENSION};
 use super::linker::LinkerInfo;
 use super::lto::{self, SerializedModule};
 use super::link::{self, remove, get_linker};
 use super::command::Command;
 use super::symbol_export::ExportedSymbols;
 
-use memmap;
+use crate::traits::*;
 use rustc_incremental::{copy_cgu_workproducts_to_incr_comp_cache_dir,
                         in_incr_comp_dir, in_incr_comp_dir_sess};
 use rustc::dep_graph::{WorkProduct, WorkProductId, WorkProductFileKind};
@@ -16,7 +16,6 @@ use rustc::session::config::{self, OutputFilenames, OutputType, Passes, Sanitize
 use rustc::session::Session;
 use rustc::util::nodemap::FxHashMap;
 use rustc::util::time_graph::{self, TimeGraph, Timeline};
-use traits::*;
 use rustc::hir::def_id::{CrateNum, LOCAL_CRATE};
 use rustc::ty::TyCtxt;
 use rustc::util::common::{time_depth, set_time_depth, print_time_passes_entry};
@@ -24,6 +23,7 @@ use rustc_fs_util::link_or_copy;
 use rustc_data_structures::svh::Svh;
 use rustc_errors::{Handler, Level, DiagnosticBuilder, FatalError, DiagnosticId};
 use rustc_errors::emitter::{Emitter};
+use rustc_target::spec::MergeFunctions;
 use syntax::attr;
 use syntax::ext::hygiene::Mark;
 use syntax_pos::MultiSpan;
@@ -41,7 +41,7 @@ use std::sync::mpsc::{channel, Sender, Receiver};
 use std::time::Instant;
 use std::thread;
 
-const PRE_THIN_LTO_BC_EXT: &str = "pre-thin-lto.bc";
+const PRE_LTO_BC_EXT: &str = "pre-lto.bc";
 
 /// Module-specific configuration for `optimize_and_codegen`.
 pub struct ModuleConfig {
@@ -58,7 +58,7 @@ pub struct ModuleConfig {
     pub pgo_use: String,
 
     // Flags indicating which outputs to produce.
-    pub emit_pre_thin_lto_bc: bool,
+    pub emit_pre_lto_bc: bool,
     pub emit_no_opt_bc: bool,
     pub emit_bc: bool,
     pub emit_bc_compressed: bool,
@@ -96,7 +96,7 @@ impl ModuleConfig {
             pgo_use: String::new(),
 
             emit_no_opt_bc: false,
-            emit_pre_thin_lto_bc: false,
+            emit_pre_lto_bc: false,
             emit_bc: false,
             emit_bc_compressed: false,
             emit_lto_bc: false,
@@ -126,7 +126,7 @@ impl ModuleConfig {
         self.time_passes = sess.time_passes();
         self.inline_threshold = sess.opts.cg.inline_threshold;
         self.obj_is_bitcode = sess.target.target.options.obj_is_bitcode ||
-                              sess.opts.debugging_opts.cross_lang_lto.enabled();
+                              sess.opts.cg.linker_plugin_lto.enabled();
         let embed_bitcode = sess.target.target.options.embed_bitcode ||
                             sess.opts.debugging_opts.embed_bitcode;
         if embed_bitcode {
@@ -152,8 +152,24 @@ impl ModuleConfig {
                             sess.opts.optimize == config::OptLevel::Aggressive &&
                             !sess.target.target.options.is_like_emscripten;
 
-        self.merge_functions = sess.opts.optimize == config::OptLevel::Default ||
-                               sess.opts.optimize == config::OptLevel::Aggressive;
+        // Some targets (namely, NVPTX) interact badly with the MergeFunctions
+        // pass. This is because MergeFunctions can generate new function calls
+        // which may interfere with the target calling convention; e.g. for the
+        // NVPTX target, PTX kernels should not call other PTX kernels.
+        // MergeFunctions can also be configured to generate aliases instead,
+        // but aliases are not supported by some backends (again, NVPTX).
+        // Therefore, allow targets to opt out of the MergeFunctions pass,
+        // but otherwise keep the pass enabled (at O2 and O3) since it can be
+        // useful for reducing code size.
+        self.merge_functions = match sess.opts.debugging_opts.merge_functions
+                                     .unwrap_or(sess.target.target.options.merge_functions) {
+            MergeFunctions::Disabled => false,
+            MergeFunctions::Trampolines |
+            MergeFunctions::Aliases => {
+                sess.opts.optimize == config::OptLevel::Default ||
+                sess.opts.optimize == config::OptLevel::Aggressive
+            }
+        };
     }
 
     pub fn bitcode_needed(&self) -> bool {
@@ -242,7 +258,7 @@ impl<B: WriteBackendMethods> CodegenContext<B> {
 
 fn generate_lto_work<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
-    needs_fat_lto: Vec<ModuleCodegen<B::Module>>,
+    needs_fat_lto: Vec<FatLTOInput<B>>,
     needs_thin_lto: Vec<(String, B::ThinBuffer)>,
     import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>
 ) -> Vec<(WorkItem<B>, u64)> {
@@ -254,9 +270,13 @@ fn generate_lto_work<B: ExtraBackendMethods>(
 
     let (lto_modules, copy_jobs) = if !needs_fat_lto.is_empty() {
         assert!(needs_thin_lto.is_empty());
-        assert!(import_only_modules.is_empty());
-        let lto_module = B::run_fat_lto(cgcx, needs_fat_lto, &mut timeline)
-            .unwrap_or_else(|e| e.raise());
+        let lto_module = B::run_fat_lto(
+            cgcx,
+            needs_fat_lto,
+            import_only_modules,
+            &mut timeline,
+        )
+        .unwrap_or_else(|e| e.raise());
         (vec![lto_module], vec![])
     } else {
         assert!(needs_fat_lto.is_empty());
@@ -286,14 +306,14 @@ fn need_crate_bitcode_for_rlib(sess: &Session) -> bool {
     sess.opts.output_types.contains_key(&OutputType::Exe)
 }
 
-fn need_pre_thin_lto_bitcode_for_incr_comp(sess: &Session) -> bool {
+fn need_pre_lto_bitcode_for_incr_comp(sess: &Session) -> bool {
     if sess.opts.incremental.is_none() {
         return false
     }
 
     match sess.lto() {
-        Lto::Fat |
         Lto::No => false,
+        Lto::Fat |
         Lto::Thin |
         Lto::ThinLocal => true,
     }
@@ -359,7 +379,7 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
     // Save all versions of the bytecode if we're saving our temporaries.
     if sess.opts.cg.save_temps {
         modules_config.emit_no_opt_bc = true;
-        modules_config.emit_pre_thin_lto_bc = true;
+        modules_config.emit_pre_lto_bc = true;
         modules_config.emit_bc = true;
         modules_config.emit_lto_bc = true;
         metadata_config.emit_bc = true;
@@ -374,8 +394,8 @@ pub fn start_async_codegen<B: ExtraBackendMethods>(
         allocator_config.emit_bc_compressed = true;
     }
 
-    modules_config.emit_pre_thin_lto_bc =
-        need_pre_thin_lto_bitcode_for_incr_comp(sess);
+    modules_config.emit_pre_lto_bc =
+        need_pre_lto_bitcode_for_incr_comp(sess);
 
     modules_config.no_integrated_as = tcx.sess.opts.cg.no_integrated_as ||
         tcx.sess.target.target.options.no_integrated_as;
@@ -646,7 +666,7 @@ pub enum WorkItem<B: WriteBackendMethods> {
     /// Copy the post-LTO artifacts from the incremental cache to the output
     /// directory.
     CopyPostLtoArtifacts(CachedModuleCodegen),
-    /// Perform (Thin)LTO on the given module.
+    /// Performs (Thin)LTO on the given module.
     LTO(lto::LtoModuleCodegen<B>),
 }
 
@@ -670,10 +690,18 @@ impl<B: WriteBackendMethods> WorkItem<B> {
 
 enum WorkItemResult<B: WriteBackendMethods> {
     Compiled(CompiledModule),
-    NeedsFatLTO(ModuleCodegen<B::Module>),
+    NeedsFatLTO(FatLTOInput<B>),
     NeedsThinLTO(String, B::ThinBuffer),
 }
 
+pub enum FatLTOInput<B: WriteBackendMethods> {
+    Serialized {
+        name: String,
+        buffer: B::ModuleBuffer,
+    },
+    InMemory(ModuleCodegen<B::Module>),
+}
+
 fn execute_work_item<B: ExtraBackendMethods>(
     cgcx: &CodegenContext<B>,
     work_item: WorkItem<B>,
@@ -721,7 +749,7 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
     // If the linker does LTO, we don't have to do it. Note that we
     // keep doing full LTO, if it is requested, as not to break the
     // assumption that the output will be a single module.
-    let linker_does_lto = cgcx.opts.debugging_opts.cross_lang_lto.enabled();
+    let linker_does_lto = cgcx.opts.cg.linker_plugin_lto.enabled();
 
     // When we're automatically doing ThinLTO for multi-codegen-unit
     // builds we don't actually want to LTO the allocator modules if
@@ -755,6 +783,15 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
         }
     };
 
+    // If we're doing some form of incremental LTO then we need to be sure to
+    // save our module to disk first.
+    let bitcode = if cgcx.config(module.kind).emit_pre_lto_bc {
+        let filename = pre_lto_bitcode_filename(&module.name);
+        cgcx.incr_comp_session_dir.as_ref().map(|path| path.join(&filename))
+    } else {
+        None
+    };
+
     Ok(match lto_type {
         ComputedLtoType::No => {
             let module = unsafe {
@@ -763,10 +800,30 @@ fn execute_optimize_work_item<B: ExtraBackendMethods>(
             WorkItemResult::Compiled(module)
         }
         ComputedLtoType::Thin => {
-            let (name, thin_buffer) = B::prepare_thin(cgcx, module);
+            let (name, thin_buffer) = B::prepare_thin(module);
+            if let Some(path) = bitcode {
+                fs::write(&path, thin_buffer.data()).unwrap_or_else(|e| {
+                    panic!("Error writing pre-lto-bitcode file `{}`: {}",
+                           path.display(),
+                           e);
+                });
+            }
             WorkItemResult::NeedsThinLTO(name, thin_buffer)
         }
-        ComputedLtoType::Fat => WorkItemResult::NeedsFatLTO(module),
+        ComputedLtoType::Fat => {
+            match bitcode {
+                Some(path) => {
+                    let (name, buffer) = B::serialize_module(module);
+                    fs::write(&path, buffer.data()).unwrap_or_else(|e| {
+                        panic!("Error writing pre-lto-bitcode file `{}`: {}",
+                               path.display(),
+                               e);
+                    });
+                    WorkItemResult::NeedsFatLTO(FatLTOInput::Serialized { name, buffer })
+                }
+                None => WorkItemResult::NeedsFatLTO(FatLTOInput::InMemory(module)),
+            }
+        }
     })
 }
 
@@ -850,7 +907,7 @@ fn execute_lto_work_item<B: ExtraBackendMethods>(
 pub enum Message<B: WriteBackendMethods> {
     Token(io::Result<Acquired>),
     NeedsFatLTO {
-        result: ModuleCodegen<B::Module>,
+        result: FatLTOInput<B>,
         worker_id: usize,
     },
     NeedsThinLTO {
@@ -965,6 +1022,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         None
     };
 
+    let ol = tcx.backend_optimization_level(LOCAL_CRATE);
     let cgcx = CodegenContext::<B> {
         backend: backend.clone(),
         crate_types: sess.crate_types.borrow().clone(),
@@ -988,7 +1046,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         regular_module_config: modules_config,
         metadata_module_config: metadata_config,
         allocator_module_config: allocator_config,
-        tm_factory: TargetMachineFactory(backend.target_machine_factory(tcx.sess, false)),
+        tm_factory: TargetMachineFactory(backend.target_machine_factory(tcx.sess, ol, false)),
         total_cgus,
         msvc_imps_needed: msvc_imps_needed(tcx),
         target_pointer_width: tcx.sess.target.target.target_pointer_width.clone(),
@@ -1780,7 +1838,7 @@ impl<B: ExtraBackendMethods> OngoingCodegen<B> {
         drop(self.coordinator_send.send(Box::new(Message::CodegenComplete::<B>)));
     }
 
-    /// Consume this context indicating that codegen was entirely aborted, and
+    /// Consumes this context indicating that codegen was entirely aborted, and
     /// we need to exit as quickly as possible.
     ///
     /// This method blocks the current thread until all worker threads have
@@ -1860,13 +1918,13 @@ pub fn submit_pre_lto_module_to_llvm<B: ExtraBackendMethods>(
 }
 
 pub fn pre_lto_bitcode_filename(module_name: &str) -> String {
-    format!("{}.{}", module_name, PRE_THIN_LTO_BC_EXT)
+    format!("{}.{}", module_name, PRE_LTO_BC_EXT)
 }
 
 fn msvc_imps_needed(tcx: TyCtxt) -> bool {
     // This should never be true (because it's not supported). If it is true,
     // something is wrong with commandline arg validation.
-    assert!(!(tcx.sess.opts.debugging_opts.cross_lang_lto.enabled() &&
+    assert!(!(tcx.sess.opts.cg.linker_plugin_lto.enabled() &&
               tcx.sess.target.target.options.is_like_msvc &&
               tcx.sess.opts.cg.prefer_dynamic));
 
@@ -1874,6 +1932,6 @@ fn msvc_imps_needed(tcx: TyCtxt) -> bool {
         tcx.sess.crate_types.borrow().iter().any(|ct| *ct == config::CrateType::Rlib) &&
     // ThinLTO can't handle this workaround in all cases, so we don't
     // emit the `__imp_` symbols. Instead we make them unnecessary by disallowing
-    // dynamic linking when cross-language LTO is enabled.
-    !tcx.sess.opts.debugging_opts.cross_lang_lto.enabled()
+    // dynamic linking when linker plugin LTO is enabled.
+    !tcx.sess.opts.cg.linker_plugin_lto.enabled()
 }
diff --git a/src/librustc_codegen_ssa/base.rs b/src/librustc_codegen_ssa/base.rs
index b88ec075653ba..7aa75f139d2ae 100644
--- a/src/librustc_codegen_ssa/base.rs
+++ b/src/librustc_codegen_ssa/base.rs
@@ -7,13 +7,13 @@
 //!
 //! Hopefully useful general knowledge about codegen:
 //!
-//!   * There's no way to find out the Ty type of a Value.  Doing so
-//!     would be "trying to get the eggs out of an omelette" (credit:
-//!     pcwalton).  You can, instead, find out its llvm::Type by calling val_ty,
-//!     but one llvm::Type corresponds to many `Ty`s; for instance, tup(int, int,
-//!     int) and rec(x=int, y=int, z=int) will have the same llvm::Type.
+//! * There's no way to find out the `Ty` type of a Value. Doing so
+//!   would be "trying to get the eggs out of an omelette" (credit:
+//!   pcwalton). You can, instead, find out its `llvm::Type` by calling `val_ty`,
+//!   but one `llvm::Type` corresponds to many `Ty`s; for instance, `tup(int, int,
+//!   int)` and `rec(x=int, y=int, z=int)` will have the same `llvm::Type`.
 
-use {ModuleCodegen, ModuleKind, CachedModuleCodegen};
+use crate::{ModuleCodegen, ModuleKind, CachedModuleCodegen};
 
 use rustc::dep_graph::cgu_reuse_tracker::CguReuse;
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
@@ -28,26 +28,26 @@ use rustc::util::common::{time, print_time_passes_entry};
 use rustc::util::profiling::ProfileCategory;
 use rustc::session::config::{self, EntryFnType, Lto};
 use rustc::session::Session;
-use mir::place::PlaceRef;
-use back::write::{OngoingCodegen, start_async_codegen, submit_pre_lto_module_to_llvm,
-    submit_post_lto_module_to_llvm};
-use {MemFlags, CrateInfo};
-use callee;
 use rustc_mir::monomorphize::item::DefPathBasedNames;
-use common::{RealPredicate, TypeKind, IntPredicate};
-use meth;
-use mir;
 use rustc::util::time_graph;
 use rustc_mir::monomorphize::Instance;
 use rustc_mir::monomorphize::partitioning::{CodegenUnit, CodegenUnitExt};
-use mono_item::MonoItem;
 use rustc::util::nodemap::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
 use rustc_data_structures::sync::Lrc;
 use rustc_codegen_utils::{symbol_names_test, check_for_rustc_errors_attr};
 use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
+use crate::mir::place::PlaceRef;
+use crate::back::write::{OngoingCodegen, start_async_codegen, submit_pre_lto_module_to_llvm,
+    submit_post_lto_module_to_llvm};
+use crate::{MemFlags, CrateInfo};
+use crate::callee;
+use crate::common::{RealPredicate, TypeKind, IntPredicate};
+use crate::meth;
+use crate::mir;
+use crate::mono_item::MonoItem;
 
-use traits::*;
+use crate::traits::*;
 
 use std::any::Any;
 use std::cmp;
@@ -58,7 +58,7 @@ use syntax_pos::Span;
 use syntax::attr;
 use rustc::hir;
 
-use mir::operand::OperandValue;
+use crate::mir::operand::OperandValue;
 
 use std::marker::PhantomData;
 
@@ -156,7 +156,7 @@ pub fn compare_simd_types<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     bx.sext(cmp, ret_ty)
 }
 
-/// Retrieve the information we are losing (making dynamic) in an unsizing
+/// Retrieves the information we are losing (making dynamic) in an unsizing
 /// adjustment.
 ///
 /// The `old_info` argument is a bit funny. It is intended for use
@@ -347,7 +347,7 @@ fn cast_shift_rhs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     }
 }
 
-/// Returns whether this session's target will use SEH-based unwinding.
+/// Returns `true` if this session's target will use SEH-based unwinding.
 ///
 /// This is only true for MSVC targets, and even then the 64-bit MSVC target
 /// currently uses SEH-ish unwinding with DWARF info tables to the side (same as
@@ -436,15 +436,13 @@ pub fn codegen_instance<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     mir::codegen_mir::<Bx>(cx, lldecl, &mir, instance, sig);
 }
 
-/// Create the `main` function which will initialize the rust runtime and call
+/// Creates the `main` function which will initialize the rust runtime and call
 /// users main function.
 pub fn maybe_create_entry_wrapper<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     cx: &'a Bx::CodegenCx
 ) {
-    let (main_def_id, span) = match *cx.sess().entry_fn.borrow() {
-        Some((id, span, _)) => {
-            (cx.tcx().hir().local_def_id(id), span)
-        }
+    let (main_def_id, span) = match cx.tcx().entry_fn(LOCAL_CRATE) {
+        Some((def_id, _)) => { (def_id, cx.tcx().def_span(def_id)) },
         None => return,
     };
 
@@ -458,7 +456,7 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
 
     let main_llfn = cx.get_fn(instance);
 
-    let et = cx.sess().entry_fn.get().map(|e| e.2);
+    let et = cx.tcx().entry_fn(LOCAL_CRATE).map(|e| e.1);
     match et {
         Some(EntryFnType::Main) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, true),
         Some(EntryFnType::Start) => create_entry_fn::<Bx>(cx, span, main_llfn, main_def_id, false),
@@ -553,7 +551,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
                                                             &["crate"],
                                                             Some("metadata")).as_str()
                                                                              .to_string();
-    let metadata_llvm_module = backend.new_metadata(tcx.sess, &metadata_cgu_name);
+    let metadata_llvm_module = backend.new_metadata(tcx, &metadata_cgu_name);
     let metadata = time(tcx.sess, "write metadata", || {
         backend.write_metadata(tcx, &metadata_llvm_module)
     });
@@ -638,7 +636,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
                                                        &["crate"],
                                                        Some("allocator")).as_str()
                                                                          .to_string();
-        let modules = backend.new_metadata(tcx.sess, &llmod_id);
+        let modules = backend.new_metadata(tcx, &llmod_id);
         time(tcx.sess, "write allocator module", || {
             backend.codegen_allocator(tcx, &modules, kind)
         });
@@ -899,6 +897,39 @@ fn is_codegened_item(tcx: TyCtxt, id: DefId) -> bool {
 }
 
 pub fn provide_both(providers: &mut Providers) {
+    providers.backend_optimization_level = |tcx, cratenum| {
+        let for_speed = match tcx.sess.opts.optimize {
+            // If globally no optimisation is done, #[optimize] has no effect.
+            //
+            // This is done because if we ended up "upgrading" to `-O2` here, we’d populate the
+            // pass manager and it is likely that some module-wide passes (such as inliner or
+            // cross-function constant propagation) would ignore the `optnone` annotation we put
+            // on the functions, thus necessarily involving these functions into optimisations.
+            config::OptLevel::No => return config::OptLevel::No,
+            // If globally optimise-speed is already specified, just use that level.
+            config::OptLevel::Less => return config::OptLevel::Less,
+            config::OptLevel::Default => return config::OptLevel::Default,
+            config::OptLevel::Aggressive => return config::OptLevel::Aggressive,
+            // If globally optimize-for-size has been requested, use -O2 instead (if optimize(size)
+            // are present).
+            config::OptLevel::Size => config::OptLevel::Default,
+            config::OptLevel::SizeMin => config::OptLevel::Default,
+        };
+
+        let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
+        for id in &*defids {
+            let hir::CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
+            match optimize {
+                attr::OptimizeAttr::None => continue,
+                attr::OptimizeAttr::Size => continue,
+                attr::OptimizeAttr::Speed => {
+                    return for_speed;
+                }
+            }
+        }
+        return tcx.sess.opts.optimize;
+    };
+
     providers.dllimport_foreign_items = |tcx, krate| {
         let module_map = tcx.foreign_modules(krate);
         let module_map = module_map.iter()
diff --git a/src/librustc_codegen_ssa/callee.rs b/src/librustc_codegen_ssa/callee.rs
index aa13e525a73bf..3665d45d1e9c7 100644
--- a/src/librustc_codegen_ssa/callee.rs
+++ b/src/librustc_codegen_ssa/callee.rs
@@ -1,4 +1,4 @@
-use traits::*;
+use crate::traits::*;
 use rustc::ty;
 use rustc::ty::subst::Substs;
 use rustc::hir::def_id::DefId;
diff --git a/src/librustc_codegen_ssa/common.rs b/src/librustc_codegen_ssa/common.rs
index cfb5d24fc12ef..1b87f160cc35d 100644
--- a/src/librustc_codegen_ssa/common.rs
+++ b/src/librustc_codegen_ssa/common.rs
@@ -5,11 +5,11 @@ use syntax_pos::{DUMMY_SP, Span};
 
 use rustc::hir::def_id::DefId;
 use rustc::middle::lang_items::LangItem;
-use base;
-use traits::*;
+use crate::base;
+use crate::traits::*;
 
 use rustc::hir;
-use traits::BuilderMethods;
+use crate::traits::BuilderMethods;
 
 pub fn type_needs_drop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, ty: Ty<'tcx>) -> bool {
     ty.needs_drop(tcx, ty::ParamEnv::reveal_all())
@@ -123,7 +123,7 @@ pub enum TypeKind {
 mod temp_stable_hash_impls {
     use rustc_data_structures::stable_hasher::{StableHasherResult, StableHasher,
                                                HashStable};
-    use ModuleCodegen;
+    use crate::ModuleCodegen;
 
     impl<HCX, M> HashStable<HCX> for ModuleCodegen<M> {
         fn hash_stable<W: StableHasherResult>(&self,
diff --git a/src/librustc_codegen_ssa/glue.rs b/src/librustc_codegen_ssa/glue.rs
index ed63e1e62ee5f..e2b49de05bd11 100644
--- a/src/librustc_codegen_ssa/glue.rs
+++ b/src/librustc_codegen_ssa/glue.rs
@@ -2,12 +2,10 @@
 //
 // Code relating to drop glue.
 
-use std;
-
-use common::IntPredicate;
-use meth;
 use rustc::ty::{self, Ty};
-use traits::*;
+use crate::common::IntPredicate;
+use crate::meth;
+use crate::traits::*;
 
 pub fn size_and_align_of_dst<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     bx: &mut Bx,
diff --git a/src/librustc_codegen_ssa/lib.rs b/src/librustc_codegen_ssa/lib.rs
index d47bd23766f69..9e1744451465d 100644
--- a/src/librustc_codegen_ssa/lib.rs
+++ b/src/librustc_codegen_ssa/lib.rs
@@ -1,6 +1,4 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
@@ -8,11 +6,12 @@
 #![feature(libc)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(in_band_lifetimes)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(nll)]
 #![allow(unused_attributes)]
 #![allow(dead_code)]
-#![feature(quote)]
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
+#![allow(elided_lifetimes_in_paths)]
 
 #![recursion_limit="256"]
 
@@ -20,27 +19,9 @@
 //! The backend-agnostic functions of this crate use functions defined in various traits that
 //! have to be implemented by each backends.
 
-#[macro_use] extern crate bitflags;
 #[macro_use] extern crate log;
-extern crate rustc_apfloat;
-#[macro_use]  extern crate rustc;
-extern crate rustc_target;
-extern crate rustc_mir;
+#[macro_use] extern crate rustc;
 #[macro_use] extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc_incremental;
-extern crate rustc_codegen_utils;
-extern crate rustc_data_structures;
-extern crate rustc_allocator;
-extern crate rustc_fs_util;
-extern crate serialize;
-extern crate rustc_errors;
-extern crate rustc_demangle;
-extern crate cc;
-extern crate libc;
-extern crate jobserver;
-extern crate memmap;
-extern crate num_cpus;
 
 use std::path::PathBuf;
 use rustc::dep_graph::WorkProduct;
@@ -71,7 +52,7 @@ pub mod back;
 pub struct ModuleCodegen<M> {
     /// The name of the module. When the crate may be saved between
     /// compilations, incremental compilation requires that name be
-    /// unique amongst **all** crates.  Therefore, it should contain
+    /// unique amongst **all** crates. Therefore, it should contain
     /// something unique to this crate (e.g., a module path) as well
     /// as the crate name and disambiguator.
     /// We currently generate these names via CodegenUnit::build_cgu_name().
@@ -136,7 +117,7 @@ pub enum ModuleKind {
     Allocator,
 }
 
-bitflags! {
+bitflags::bitflags! {
     pub struct MemFlags: u8 {
         const VOLATILE = 1 << 0;
         const NONTEMPORAL = 1 << 1;
@@ -144,7 +125,7 @@ bitflags! {
     }
 }
 
-/// Misc info we load from metadata to persist beyond the tcx
+/// Misc info we load from metadata to persist beyond the tcx.
 pub struct CrateInfo {
     pub panic_runtime: Option<CrateNum>,
     pub compiler_builtins: Option<CrateNum>,
diff --git a/src/librustc_codegen_ssa/meth.rs b/src/librustc_codegen_ssa/meth.rs
index 98ad2616eeaae..49f3c87ee2d9d 100644
--- a/src/librustc_codegen_ssa/meth.rs
+++ b/src/librustc_codegen_ssa/meth.rs
@@ -1,8 +1,8 @@
 use rustc_target::abi::call::FnType;
-use callee;
 use rustc_mir::monomorphize;
 
-use traits::*;
+use crate::callee;
+use crate::traits::*;
 
 use rustc::ty::{self, Ty};
 
diff --git a/src/librustc_codegen_ssa/mir/analyze.rs b/src/librustc_codegen_ssa/mir/analyze.rs
index f3475d1c48968..9fe2e58bc203c 100644
--- a/src/librustc_codegen_ssa/mir/analyze.rs
+++ b/src/librustc_codegen_ssa/mir/analyze.rs
@@ -10,7 +10,7 @@ use rustc::mir::traversal;
 use rustc::ty;
 use rustc::ty::layout::{LayoutOf, HasTyCtxt};
 use super::FunctionCx;
-use traits::*;
+use crate::traits::*;
 
 pub fn non_ssa_locals<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     fx: &FunctionCx<'a, 'tcx, Bx>
diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index aa82c853257a3..caca1789fc98c 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -5,13 +5,13 @@ use rustc::mir;
 use rustc::mir::interpret::EvalErrorKind;
 use rustc_target::abi::call::{ArgType, FnType, PassMode};
 use rustc_target::spec::abi::Abi;
-use base;
-use MemFlags;
-use common::{self, IntPredicate};
-use meth;
 use rustc_mir::monomorphize;
+use crate::base;
+use crate::MemFlags;
+use crate::common::{self, IntPredicate};
+use crate::meth;
 
-use traits::*;
+use crate::traits::*;
 
 use syntax::symbol::Symbol;
 use syntax_pos::Pos;
@@ -884,7 +884,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
     }
 
-    /// Return the landingpad wrapper around the given basic block
+    /// Returns the landing-pad wrapper around the given basic block.
     ///
     /// No-op in MSVC SEH scheme.
     fn landing_pad_to(
diff --git a/src/librustc_codegen_ssa/mir/constant.rs b/src/librustc_codegen_ssa/mir/constant.rs
index e6d6ef1d7a38b..6bc69efa4a7d5 100644
--- a/src/librustc_codegen_ssa/mir/constant.rs
+++ b/src/librustc_codegen_ssa/mir/constant.rs
@@ -6,7 +6,7 @@ use rustc::mir::interpret::GlobalId;
 use rustc::ty::{self, Ty};
 use rustc::ty::layout;
 use syntax::source_map::Span;
-use traits::*;
+use crate::traits::*;
 
 use super::FunctionCx;
 
@@ -59,7 +59,6 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     let field = const_field(
                         bx.tcx(),
                         ty::ParamEnv::reveal_all(),
-                        self.instance,
                         None,
                         mir::Field::new(field as usize),
                         c,
diff --git a/src/librustc_codegen_ssa/mir/mod.rs b/src/librustc_codegen_ssa/mir/mod.rs
index 85a663dacdcc5..203d84bff5bb3 100644
--- a/src/librustc_codegen_ssa/mir/mod.rs
+++ b/src/librustc_codegen_ssa/mir/mod.rs
@@ -4,11 +4,11 @@ use rustc::ty::layout::{TyLayout, HasTyCtxt};
 use rustc::mir::{self, Mir};
 use rustc::ty::subst::Substs;
 use rustc::session::config::DebugInfo;
-use base;
-use debuginfo::{self, VariableAccess, VariableKind, FunctionDebugContext};
 use rustc_mir::monomorphize::Instance;
 use rustc_target::abi::call::{FnType, PassMode};
-use traits::*;
+use crate::base;
+use crate::debuginfo::{self, VariableAccess, VariableKind, FunctionDebugContext};
+use crate::traits::*;
 
 use syntax_pos::{DUMMY_SP, NO_EXPANSION, BytePos, Span};
 use syntax::symbol::keywords;
@@ -422,7 +422,7 @@ fn create_funclets<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
     }).unzip()
 }
 
-/// Produce, for each argument, a `Value` pointing at the
+/// Produces, for each argument, a `Value` pointing at the
 /// argument's value. As arguments are places, these are always
 /// indirect.
 fn arg_local_refs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
@@ -586,10 +586,17 @@ fn arg_local_refs<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
                 return;
             }
 
+            let pin_did = tcx.lang_items().pin_type();
             // Or is it the closure environment?
             let (closure_layout, env_ref) = match arg.layout.ty.sty {
                 ty::RawPtr(ty::TypeAndMut { ty, .. }) |
                 ty::Ref(_, ty, _)  => (bx.layout_of(ty), true),
+                ty::Adt(def, substs) if Some(def.did) == pin_did => {
+                    match substs.type_at(0).sty {
+                        ty::Ref(_, ty, _)  => (bx.layout_of(ty), true),
+                        _ => (arg.layout, false),
+                    }
+                }
                 _ => (arg.layout, false)
             };
 
diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs
index 2026e042ef0eb..2c6d968bb032a 100644
--- a/src/librustc_codegen_ssa/mir/operand.rs
+++ b/src/librustc_codegen_ssa/mir/operand.rs
@@ -3,11 +3,11 @@ use rustc::mir;
 use rustc::ty;
 use rustc::ty::layout::{self, Align, LayoutOf, TyLayout};
 
-use base;
-use MemFlags;
-use glue;
+use crate::base;
+use crate::MemFlags;
+use crate::glue;
 
-use traits::*;
+use crate::traits::*;
 
 use std::fmt;
 
@@ -88,9 +88,9 @@ impl<'a, 'tcx: 'a, V: CodegenObject> OperandRef<'tcx, V> {
                 );
                 OperandValue::Immediate(llval)
             },
-            ConstValue::ScalarPair(a, b) => {
-                let (a_scalar, b_scalar) = match layout.abi {
-                    layout::Abi::ScalarPair(ref a, ref b) => (a, b),
+            ConstValue::Slice(a, b) => {
+                let a_scalar = match layout.abi {
+                    layout::Abi::ScalarPair(ref a, _) => a,
                     _ => bug!("from_const: invalid ScalarPair layout: {:#?}", layout)
                 };
                 let a_llval = bx.cx().scalar_to_backend(
@@ -98,11 +98,7 @@ impl<'a, 'tcx: 'a, V: CodegenObject> OperandRef<'tcx, V> {
                     a_scalar,
                     bx.cx().scalar_pair_element_backend_type(layout, 0, true),
                 );
-                let b_llval = bx.cx().scalar_to_backend(
-                    b,
-                    b_scalar,
-                    bx.cx().scalar_pair_element_backend_type(layout, 1, true),
-                );
+                let b_llval = bx.cx().const_usize(b);
                 OperandValue::Pair(a_llval, b_llval)
             },
             ConstValue::ByRef(_, alloc, offset) => {
diff --git a/src/librustc_codegen_ssa/mir/place.rs b/src/librustc_codegen_ssa/mir/place.rs
index b10611e5ac797..9d6826d8756b7 100644
--- a/src/librustc_codegen_ssa/mir/place.rs
+++ b/src/librustc_codegen_ssa/mir/place.rs
@@ -2,27 +2,27 @@ use rustc::ty::{self, Ty};
 use rustc::ty::layout::{self, Align, TyLayout, LayoutOf, VariantIdx, HasTyCtxt};
 use rustc::mir;
 use rustc::mir::tcx::PlaceTy;
-use MemFlags;
-use common::IntPredicate;
-use glue;
+use crate::MemFlags;
+use crate::common::IntPredicate;
+use crate::glue;
 
-use traits::*;
+use crate::traits::*;
 
 use super::{FunctionCx, LocalRef};
 use super::operand::OperandValue;
 
 #[derive(Copy, Clone, Debug)]
 pub struct PlaceRef<'tcx, V> {
-    /// Pointer to the contents of the place
+    /// Pointer to the contents of the place.
     pub llval: V,
 
-    /// This place's extra data if it is unsized, or null
+    /// This place's extra data if it is unsized, or null.
     pub llextra: Option<V>,
 
-    /// Monomorphized type of this place, including variant information
+    /// Monomorphized type of this place, including variant information.
     pub layout: TyLayout<'tcx>,
 
-    /// What alignment we know for this place
+    /// What alignment we know for this place.
     pub align: Align,
 }
 
@@ -41,6 +41,21 @@ impl<'a, 'tcx: 'a, V: CodegenObject> PlaceRef<'tcx, V> {
         }
     }
 
+    fn new_thin_place<Bx: BuilderMethods<'a, 'tcx, Value = V>>(
+        bx: &mut Bx,
+        llval: V,
+        layout: TyLayout<'tcx>,
+        align: Align,
+    ) -> PlaceRef<'tcx, V> {
+        assert!(!bx.cx().type_has_metadata(layout.ty));
+        PlaceRef {
+            llval,
+            llextra: None,
+            layout,
+            align
+        }
+    }
+
     pub fn alloca<Bx: BuilderMethods<'a, 'tcx, Value = V>>(
         bx: &mut Bx,
         layout: TyLayout<'tcx>,
@@ -262,7 +277,7 @@ impl<'a, 'tcx: 'a, V: CodegenObject> PlaceRef<'tcx, V> {
         }
     }
 
-    /// Set the discriminant for a new value of the given case of the given
+    /// Sets the discriminant for a new value of the given case of the given
     /// representation.
     pub fn codegen_set_discr<Bx: BuilderMethods<'a, 'tcx, Value = V>>(
         &self,
@@ -421,8 +436,10 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 }
             }
             mir::Place::Static(box mir::Static { def_id, ty }) => {
+                // NB: The layout of a static may be unsized as is the case when working
+                // with a static that is an extern_type.
                 let layout = cx.layout_of(self.monomorphize(&ty));
-                PlaceRef::new_sized(bx.get_static(def_id), layout, layout.align.abi)
+                PlaceRef::new_thin_place(bx, bx.get_static(def_id), layout, layout.align.abi)
             },
             mir::Place::Projection(box mir::Projection {
                 ref base,
diff --git a/src/librustc_codegen_ssa/mir/rvalue.rs b/src/librustc_codegen_ssa/mir/rvalue.rs
index 9ca5414fa717e..25a7754d118d7 100644
--- a/src/librustc_codegen_ssa/mir/rvalue.rs
+++ b/src/librustc_codegen_ssa/mir/rvalue.rs
@@ -6,13 +6,13 @@ use rustc::middle::lang_items::ExchangeMallocFnLangItem;
 use rustc_apfloat::{ieee, Float, Status, Round};
 use std::{u128, i128};
 
-use base;
-use MemFlags;
-use callee;
-use common::{self, RealPredicate, IntPredicate};
+use crate::base;
+use crate::MemFlags;
+use crate::callee;
+use crate::common::{self, RealPredicate, IntPredicate};
 use rustc_mir::monomorphize;
 
-use traits::*;
+use crate::traits::*;
 
 use super::{FunctionCx, LocalRef};
 use super::operand::{OperandRef, OperandValue};
diff --git a/src/librustc_codegen_ssa/mir/statement.rs b/src/librustc_codegen_ssa/mir/statement.rs
index 9561a57d0a7de..a1bd919c43354 100644
--- a/src/librustc_codegen_ssa/mir/statement.rs
+++ b/src/librustc_codegen_ssa/mir/statement.rs
@@ -1,10 +1,10 @@
 use rustc::mir;
 
-use traits::BuilderMethods;
+use crate::traits::BuilderMethods;
 use super::FunctionCx;
 use super::LocalRef;
 use super::OperandValue;
-use traits::*;
+use crate::traits::*;
 
 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_statement(
diff --git a/src/librustc_codegen_ssa/mono_item.rs b/src/librustc_codegen_ssa/mono_item.rs
index 21e0044759a5a..bfb6a9153809a 100644
--- a/src/librustc_codegen_ssa/mono_item.rs
+++ b/src/librustc_codegen_ssa/mono_item.rs
@@ -1,10 +1,10 @@
-use base;
 use rustc::hir;
 use rustc::hir::def::Def;
 use rustc::mir::mono::{Linkage, Visibility};
 use rustc::ty::layout::HasTyCtxt;
 use std::fmt;
-use traits::*;
+use crate::base;
+use crate::traits::*;
 
 pub use rustc::mir::mono::MonoItem;
 
@@ -13,7 +13,7 @@ pub use rustc_mir::monomorphize::item::MonoItemExt as BaseMonoItemExt;
 pub trait MonoItemExt<'a, 'tcx: 'a>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
     fn define<Bx: BuilderMethods<'a, 'tcx>>(&self, cx: &'a Bx::CodegenCx) {
         debug!("BEGIN IMPLEMENTING '{} ({})' in cgu {}",
-               self.to_string(cx.tcx()),
+               self.to_string(cx.tcx(), true),
                self.to_raw_string(),
                cx.codegen_unit().name());
 
@@ -45,7 +45,7 @@ pub trait MonoItemExt<'a, 'tcx: 'a>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
         }
 
         debug!("END IMPLEMENTING '{} ({})' in cgu {}",
-               self.to_string(cx.tcx()),
+               self.to_string(cx.tcx(), true),
                self.to_raw_string(),
                cx.codegen_unit().name());
     }
@@ -57,7 +57,7 @@ pub trait MonoItemExt<'a, 'tcx: 'a>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
         visibility: Visibility
     ) {
         debug!("BEGIN PREDEFINING '{} ({})' in cgu {}",
-               self.to_string(cx.tcx()),
+               self.to_string(cx.tcx(), true),
                self.to_raw_string(),
                cx.codegen_unit().name());
 
@@ -76,7 +76,7 @@ pub trait MonoItemExt<'a, 'tcx: 'a>: fmt::Debug + BaseMonoItemExt<'a, 'tcx> {
         }
 
         debug!("END PREDEFINING '{} ({})' in cgu {}",
-               self.to_string(cx.tcx()),
+               self.to_string(cx.tcx(), true),
                self.to_raw_string(),
                cx.codegen_unit().name());
     }
diff --git a/src/librustc_codegen_ssa/traits/asm.rs b/src/librustc_codegen_ssa/traits/asm.rs
index 7fe16925a3f97..a95bf3af5bf27 100644
--- a/src/librustc_codegen_ssa/traits/asm.rs
+++ b/src/librustc_codegen_ssa/traits/asm.rs
@@ -1,5 +1,5 @@
 use super::BackendTypes;
-use mir::place::PlaceRef;
+use crate::mir::place::PlaceRef;
 use rustc::hir::{GlobalAsm, InlineAsm};
 
 pub trait AsmBuilderMethods<'tcx>: BackendTypes {
diff --git a/src/librustc_codegen_ssa/traits/backend.rs b/src/librustc_codegen_ssa/traits/backend.rs
index 8c026059dc490..73c7614d91393 100644
--- a/src/librustc_codegen_ssa/traits/backend.rs
+++ b/src/librustc_codegen_ssa/traits/backend.rs
@@ -6,7 +6,7 @@ use super::CodegenObject;
 use rustc::middle::allocator::AllocatorKind;
 use rustc::middle::cstore::EncodedMetadata;
 use rustc::mir::mono::Stats;
-use rustc::session::Session;
+use rustc::session::{Session, config};
 use rustc::ty::TyCtxt;
 use rustc_codegen_utils::codegen_backend::CodegenBackend;
 use std::sync::Arc;
@@ -32,7 +32,7 @@ impl<'tcx, T> Backend<'tcx> for T where
 }
 
 pub trait ExtraBackendMethods: CodegenBackend + WriteBackendMethods + Sized + Send {
-    fn new_metadata(&self, sess: &Session, mod_name: &str) -> Self::Module;
+    fn new_metadata(&self, sess: TyCtxt, mod_name: &str) -> Self::Module;
     fn write_metadata<'b, 'gcx>(
         &self,
         tcx: TyCtxt<'b, 'gcx, 'gcx>,
@@ -50,6 +50,7 @@ pub trait ExtraBackendMethods: CodegenBackend + WriteBackendMethods + Sized + Se
     fn target_machine_factory(
         &self,
         sess: &Session,
+        opt_level: config::OptLevel,
         find_features: bool,
     ) -> Arc<dyn Fn() -> Result<Self::TargetMachine, String> + Send + Sync>;
     fn target_cpu<'b>(&self, sess: &'b Session) -> &'b str;
diff --git a/src/librustc_codegen_ssa/traits/builder.rs b/src/librustc_codegen_ssa/traits/builder.rs
index bc66087d3ce70..bda0f3dc77966 100644
--- a/src/librustc_codegen_ssa/traits/builder.rs
+++ b/src/librustc_codegen_ssa/traits/builder.rs
@@ -4,13 +4,14 @@ use super::debuginfo::DebugInfoBuilderMethods;
 use super::intrinsic::IntrinsicCallMethods;
 use super::type_::ArgTypeMethods;
 use super::{HasCodegen, StaticBuilderMethods};
-use common::{AtomicOrdering, AtomicRmwBinOp, IntPredicate, RealPredicate, SynchronizationScope};
-use mir::operand::OperandRef;
-use mir::place::PlaceRef;
+use crate::common::{AtomicOrdering, AtomicRmwBinOp, IntPredicate, RealPredicate,
+    SynchronizationScope};
+use crate::mir::operand::OperandRef;
+use crate::mir::place::PlaceRef;
+use crate::MemFlags;
 use rustc::ty::Ty;
 use rustc::ty::layout::{Align, Size};
 use std::ffi::CStr;
-use MemFlags;
 
 use std::borrow::Cow;
 use std::ops::Range;
diff --git a/src/librustc_codegen_ssa/traits/consts.rs b/src/librustc_codegen_ssa/traits/consts.rs
index 482fb67e2b0c2..319f4b4e5e4b5 100644
--- a/src/librustc_codegen_ssa/traits/consts.rs
+++ b/src/librustc_codegen_ssa/traits/consts.rs
@@ -1,5 +1,5 @@
 use super::BackendTypes;
-use mir::place::PlaceRef;
+use crate::mir::place::PlaceRef;
 use rustc::mir::interpret::Allocation;
 use rustc::mir::interpret::Scalar;
 use rustc::ty::layout;
diff --git a/src/librustc_codegen_ssa/traits/debuginfo.rs b/src/librustc_codegen_ssa/traits/debuginfo.rs
index 4163faa591462..0e606e744c629 100644
--- a/src/librustc_codegen_ssa/traits/debuginfo.rs
+++ b/src/librustc_codegen_ssa/traits/debuginfo.rs
@@ -1,5 +1,5 @@
 use super::BackendTypes;
-use debuginfo::{FunctionDebugContext, MirDebugScope, VariableAccess, VariableKind};
+use crate::debuginfo::{FunctionDebugContext, MirDebugScope, VariableAccess, VariableKind};
 use rustc::hir::def_id::CrateNum;
 use rustc::mir;
 use rustc::ty::{self, Ty};
diff --git a/src/librustc_codegen_ssa/traits/declare.rs b/src/librustc_codegen_ssa/traits/declare.rs
index 3cd3c4e48b998..6a400a7d7a45d 100644
--- a/src/librustc_codegen_ssa/traits/declare.rs
+++ b/src/librustc_codegen_ssa/traits/declare.rs
@@ -29,7 +29,7 @@ pub trait DeclareMethods<'tcx>: BackendTypes {
     /// Declare a global with an intention to define it.
     ///
     /// Use this function when you intend to define a global. This function will
-    /// return None if the name already has a definition associated with it. In that
+    /// return `None` if the name already has a definition associated with it. In that
     /// case an error should be reported to the user, because it usually happens due
     /// to user’s fault (e.g., misuse of #[no_mangle] or #[export_name] attributes).
     fn define_global(&self, name: &str, ty: Self::Type) -> Option<Self::Value>;
@@ -53,10 +53,10 @@ pub trait DeclareMethods<'tcx>: BackendTypes {
     /// can happen with #[no_mangle] or #[export_name], for example.
     fn define_internal_fn(&self, name: &str, fn_sig: ty::PolyFnSig<'tcx>) -> Self::Value;
 
-    /// Get declared value by name.
+    /// Gets declared value by name.
     fn get_declared_value(&self, name: &str) -> Option<Self::Value>;
 
-    /// Get defined or externally defined (AvailableExternally linkage) value by
+    /// Gets defined or externally defined (AvailableExternally linkage) value by
     /// name.
     fn get_defined_value(&self, name: &str) -> Option<Self::Value>;
 }
diff --git a/src/librustc_codegen_ssa/traits/intrinsic.rs b/src/librustc_codegen_ssa/traits/intrinsic.rs
index a2d6b0550f8ca..3cd0c39d4139a 100644
--- a/src/librustc_codegen_ssa/traits/intrinsic.rs
+++ b/src/librustc_codegen_ssa/traits/intrinsic.rs
@@ -1,5 +1,5 @@
 use super::BackendTypes;
-use mir::operand::OperandRef;
+use crate::mir::operand::OperandRef;
 use rustc::ty::Ty;
 use rustc_target::abi::call::FnType;
 use syntax_pos::Span;
diff --git a/src/librustc_codegen_ssa/traits/type_.rs b/src/librustc_codegen_ssa/traits/type_.rs
index 2ec0c8e5a75cc..7c5e615f22452 100644
--- a/src/librustc_codegen_ssa/traits/type_.rs
+++ b/src/librustc_codegen_ssa/traits/type_.rs
@@ -1,8 +1,8 @@
 use super::misc::MiscMethods;
 use super::Backend;
 use super::HasCodegen;
-use common::{self, TypeKind};
-use mir::place::PlaceRef;
+use crate::common::{self, TypeKind};
+use crate::mir::place::PlaceRef;
 use rustc::ty::layout::{self, Align, Size, TyLayout};
 use rustc::ty::{self, Ty};
 use rustc::util::nodemap::FxHashMap;
@@ -39,13 +39,13 @@ pub trait BaseTypeMethods<'tcx>: Backend<'tcx> {
     fn type_ptr_to(&self, ty: Self::Type) -> Self::Type;
     fn element_type(&self, ty: Self::Type) -> Self::Type;
 
-    /// Return the number of elements in `self` if it is a LLVM vector type.
+    /// Returns the number of elements in `self` if it is a LLVM vector type.
     fn vector_length(&self, ty: Self::Type) -> usize;
 
     fn func_params_types(&self, ty: Self::Type) -> Vec<Self::Type>;
     fn float_width(&self, ty: Self::Type) -> usize;
 
-    /// Retrieve the bit width of the integer type `self`.
+    /// Retrieves the bit width of the integer type `self`.
     fn int_width(&self, ty: Self::Type) -> u64;
 
     fn val_ty(&self, v: Self::Value) -> Self::Type;
diff --git a/src/librustc_codegen_ssa/traits/write.rs b/src/librustc_codegen_ssa/traits/write.rs
index cea89a7f99b1b..d8fb7c608c8af 100644
--- a/src/librustc_codegen_ssa/traits/write.rs
+++ b/src/librustc_codegen_ssa/traits/write.rs
@@ -1,6 +1,6 @@
-use back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
-use back::write::{CodegenContext, ModuleConfig};
-use {CompiledModule, ModuleCodegen};
+use crate::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule};
+use crate::back::write::{CodegenContext, ModuleConfig, FatLTOInput};
+use crate::{CompiledModule, ModuleCodegen};
 
 use rustc::dep_graph::WorkProduct;
 use rustc::util::time_graph::Timeline;
@@ -18,7 +18,8 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
     /// for further optimization.
     fn run_fat_lto(
         cgcx: &CodegenContext<Self>,
-        modules: Vec<ModuleCodegen<Self::Module>>,
+        modules: Vec<FatLTOInput<Self>>,
+        cached_modules: Vec<(SerializedModule<Self::ModuleBuffer>, WorkProduct)>,
         timeline: &mut Timeline,
     ) -> Result<LtoModuleCodegen<Self>, FatalError>;
     /// Performs thin LTO by performing necessary global analysis and returning two
@@ -51,9 +52,11 @@ pub trait WriteBackendMethods: 'static + Sized + Clone {
         timeline: &mut Timeline,
     ) -> Result<CompiledModule, FatalError>;
     fn prepare_thin(
-        cgcx: &CodegenContext<Self>,
         module: ModuleCodegen<Self::Module>
     ) -> (String, Self::ThinBuffer);
+    fn serialize_module(
+        module: ModuleCodegen<Self::Module>
+    ) -> (String, Self::ModuleBuffer);
     fn run_lto_pass_manager(
         cgcx: &CodegenContext<Self>,
         llmod: &ModuleCodegen<Self::Module>,
diff --git a/src/librustc_codegen_utils/Cargo.toml b/src/librustc_codegen_utils/Cargo.toml
index 34a09f30b6411..5f241eb20fb55 100644
--- a/src/librustc_codegen_utils/Cargo.toml
+++ b/src/librustc_codegen_utils/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_codegen_utils"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_codegen_utils"
diff --git a/src/librustc_codegen_utils/codegen_backend.rs b/src/librustc_codegen_utils/codegen_backend.rs
index 8981c542961e2..28d7d18422841 100644
--- a/src/librustc_codegen_utils/codegen_backend.rs
+++ b/src/librustc_codegen_utils/codegen_backend.rs
@@ -4,9 +4,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![deny(warnings)]
 
 #![feature(box_syntax)]
@@ -31,7 +29,7 @@ use rustc::middle::cstore::EncodedMetadata;
 use rustc::middle::cstore::MetadataLoader;
 use rustc::dep_graph::DepGraph;
 use rustc_target::spec::Target;
-use link::out_filename;
+use crate::link::out_filename;
 
 pub use rustc_data_structures::sync::MetadataRef;
 
@@ -44,8 +42,8 @@ pub trait CodegenBackend {
     fn diagnostics(&self) -> &[(&'static str, &'static str)] { &[] }
 
     fn metadata_loader(&self) -> Box<dyn MetadataLoader + Sync>;
-    fn provide(&self, _providers: &mut Providers);
-    fn provide_extern(&self, _providers: &mut Providers);
+    fn provide(&self, _providers: &mut Providers<'_>);
+    fn provide_extern(&self, _providers: &mut Providers<'_>);
     fn codegen_crate<'a, 'tcx>(
         &self,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -111,8 +109,8 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
         box NoLlvmMetadataLoader
     }
 
-    fn provide(&self, providers: &mut Providers) {
-        ::symbol_names::provide(providers);
+    fn provide(&self, providers: &mut Providers<'_>) {
+        crate::symbol_names::provide(providers);
 
         providers.target_features_whitelist = |_tcx, _cnum| {
             Default::default() // Just a dummy
@@ -120,7 +118,7 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
         providers.is_reachable_non_generic = |_tcx, _defid| true;
         providers.exported_symbols = |_tcx, _crate| Arc::new(Vec::new());
     }
-    fn provide_extern(&self, providers: &mut Providers) {
+    fn provide_extern(&self, providers: &mut Providers<'_>) {
         providers.is_reachable_non_generic = |_tcx, _defid| true;
     }
 
@@ -131,12 +129,12 @@ impl CodegenBackend for MetadataOnlyCodegenBackend {
     ) -> Box<dyn Any> {
         use rustc_mir::monomorphize::item::MonoItem;
 
-        ::check_for_rustc_errors_attr(tcx);
-        ::symbol_names_test::report_symbol_names(tcx);
-        ::rustc_incremental::assert_dep_graph(tcx);
-        ::rustc_incremental::assert_module_sources::assert_module_sources(tcx);
+        crate::check_for_rustc_errors_attr(tcx);
+        crate::symbol_names_test::report_symbol_names(tcx);
+        rustc_incremental::assert_dep_graph(tcx);
+        rustc_incremental::assert_module_sources::assert_module_sources(tcx);
         // FIXME: Fix this
-        // ::rustc::middle::dependency_format::calculate(tcx);
+        // rustc::middle::dependency_format::calculate(tcx);
         let _ = tcx.link_args(LOCAL_CRATE);
         let _ = tcx.native_libraries(LOCAL_CRATE);
         let (_, cgus) = tcx.collect_and_partition_mono_items(LOCAL_CRATE);
diff --git a/src/librustc_codegen_utils/lib.rs b/src/librustc_codegen_utils/lib.rs
index b59bca0ae0edb..2b70141894be9 100644
--- a/src/librustc_codegen_utils/lib.rs
+++ b/src/librustc_codegen_utils/lib.rs
@@ -2,35 +2,26 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(custom_attribute)]
 #![feature(nll)]
 #![allow(unused_attributes)]
-#![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
+#![feature(in_band_lifetimes)]
 
 #![recursion_limit="256"]
 
-extern crate flate2;
-#[macro_use]
-extern crate log;
+#![deny(rust_2018_idioms)]
 
 #[macro_use]
 extern crate rustc;
-extern crate rustc_target;
-extern crate rustc_metadata;
-extern crate rustc_mir;
-extern crate rustc_incremental;
-extern crate syntax;
-extern crate syntax_pos;
 #[macro_use] extern crate rustc_data_structures;
 
 use rustc::ty::TyCtxt;
+use rustc::hir::def_id::LOCAL_CRATE;
 
 pub mod link;
 pub mod codegen_backend;
@@ -41,12 +32,10 @@ pub mod symbol_names_test;
 /// error in codegen. This is used to write compile-fail tests
 /// that actually test that compilation succeeds without
 /// reporting an error.
-pub fn check_for_rustc_errors_attr(tcx: TyCtxt) {
-    if let Some((id, span, _)) = *tcx.sess.entry_fn.borrow() {
-        let main_def_id = tcx.hir().local_def_id(id);
-
-        if tcx.has_attr(main_def_id, "rustc_error") {
-            tcx.sess.span_fatal(span, "compilation successful");
+pub fn check_for_rustc_errors_attr(tcx: TyCtxt<'_, '_, '_>) {
+    if let Some((def_id, _)) = tcx.entry_fn(LOCAL_CRATE) {
+        if tcx.has_attr(def_id, "rustc_error") {
+            tcx.sess.span_fatal(tcx.def_span(def_id), "compilation successful");
         }
     }
 }
diff --git a/src/librustc_codegen_utils/link.rs b/src/librustc_codegen_utils/link.rs
index 09e22bd2c91a9..f3a1b219f8a84 100644
--- a/src/librustc_codegen_utils/link.rs
+++ b/src/librustc_codegen_utils/link.rs
@@ -41,7 +41,7 @@ pub fn find_crate_name(sess: Option<&Session>,
                        attrs: &[ast::Attribute],
                        input: &Input) -> String {
     let validate = |s: String, span: Option<Span>| {
-        ::rustc_metadata::validate_crate_name(sess, &s, span);
+        rustc_metadata::validate_crate_name(sess, &s, span);
         s
     };
 
diff --git a/src/librustc_codegen_utils/symbol_names.rs b/src/librustc_codegen_utils/symbol_names.rs
index 9267f14f24234..8d105853d92f1 100644
--- a/src/librustc_codegen_utils/symbol_names.rs
+++ b/src/librustc_codegen_utils/symbol_names.rs
@@ -103,10 +103,12 @@ use rustc_mir::monomorphize::Instance;
 
 use syntax_pos::symbol::Symbol;
 
+use log::debug;
+
 use std::fmt::Write;
 use std::mem::discriminant;
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         def_symbol_name,
         symbol_name,
@@ -221,7 +223,7 @@ fn get_symbol_hash<'a, 'tcx>(
 }
 
 fn def_symbol_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> ty::SymbolName {
-    let mut buffer = SymbolPathBuffer::new();
+    let mut buffer = SymbolPathBuffer::new(tcx);
     item_path::with_forced_absolute_paths(|| {
         tcx.push_item_path(&mut buffer, def_id, false);
     });
@@ -317,7 +319,7 @@ fn compute_symbol_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, instance: Instance
 
     let hash = get_symbol_hash(tcx, def_id, instance, instance_ty, substs);
 
-    let mut buf = SymbolPathBuffer::from_interned(tcx.def_symbol_name(def_id));
+    let mut buf = SymbolPathBuffer::from_interned(tcx.def_symbol_name(def_id), tcx);
 
     if instance.is_vtable_shim() {
         buf.push("{{vtable-shim}}");
@@ -343,22 +345,25 @@ fn compute_symbol_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, instance: Instance
 struct SymbolPathBuffer {
     result: String,
     temp_buf: String,
+    strict_naming: bool,
 }
 
 impl SymbolPathBuffer {
-    fn new() -> Self {
+    fn new(tcx: TyCtxt<'_, '_, '_>) -> Self {
         let mut result = SymbolPathBuffer {
             result: String::with_capacity(64),
             temp_buf: String::with_capacity(16),
+            strict_naming: tcx.has_strict_asm_symbol_naming(),
         };
         result.result.push_str("_ZN"); // _Z == Begin name-sequence, N == nested
         result
     }
 
-    fn from_interned(symbol: ty::SymbolName) -> Self {
+    fn from_interned(symbol: ty::SymbolName, tcx: TyCtxt<'_, '_, '_>) -> Self {
         let mut result = SymbolPathBuffer {
             result: String::with_capacity(64),
             temp_buf: String::with_capacity(16),
+            strict_naming: tcx.has_strict_asm_symbol_naming(),
         };
         result.result.push_str(&symbol.as_str());
         result
@@ -375,68 +380,88 @@ impl SymbolPathBuffer {
         let _ = write!(self.result, "17h{:016x}E", hash);
         self.result
     }
-}
 
-impl ItemPathBuffer for SymbolPathBuffer {
-    fn root_mode(&self) -> &RootMode {
-        const ABSOLUTE: &RootMode = &RootMode::Absolute;
-        ABSOLUTE
-    }
-
-    fn push(&mut self, text: &str) {
+    // Name sanitation. LLVM will happily accept identifiers with weird names, but
+    // gas doesn't!
+    // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
+    // NVPTX assembly has more strict naming rules than gas, so additionally, dots
+    // are replaced with '$' there.
+    fn sanitize_and_append(&mut self, s: &str) {
         self.temp_buf.clear();
-        let need_underscore = sanitize(&mut self.temp_buf, text);
+
+        for c in s.chars() {
+            match c {
+                // Escape these with $ sequences
+                '@' => self.temp_buf.push_str("$SP$"),
+                '*' => self.temp_buf.push_str("$BP$"),
+                '&' => self.temp_buf.push_str("$RF$"),
+                '<' => self.temp_buf.push_str("$LT$"),
+                '>' => self.temp_buf.push_str("$GT$"),
+                '(' => self.temp_buf.push_str("$LP$"),
+                ')' => self.temp_buf.push_str("$RP$"),
+                ',' => self.temp_buf.push_str("$C$"),
+
+                '-' | ':' => if self.strict_naming {
+                    // NVPTX doesn't support these characters in symbol names.
+                    self.temp_buf.push('$')
+                }
+                else {
+                    // '.' doesn't occur in types and functions, so reuse it
+                    // for ':' and '-'
+                    self.temp_buf.push('.')
+                },
+
+                '.' => if self.strict_naming {
+                    self.temp_buf.push('$')
+                }
+                else {
+                    self.temp_buf.push('.')
+                },
+
+                // These are legal symbols
+                'a'..='z' | 'A'..='Z' | '0'..='9' | '_' | '$' => self.temp_buf.push(c),
+
+                _ => {
+                    self.temp_buf.push('$');
+                    for c in c.escape_unicode().skip(1) {
+                        match c {
+                            '{' => {}
+                            '}' => self.temp_buf.push('$'),
+                            c => self.temp_buf.push(c),
+                        }
+                    }
+                }
+            }
+        }
+
+        let need_underscore = {
+            // Underscore-qualify anything that didn't start as an ident.
+            !self.temp_buf.is_empty()
+                && self.temp_buf.as_bytes()[0] != '_' as u8
+                && !(self.temp_buf.as_bytes()[0] as char).is_xid_start()
+        };
+
         let _ = write!(
             self.result,
             "{}",
             self.temp_buf.len() + (need_underscore as usize)
         );
+
         if need_underscore {
             self.result.push('_');
         }
+
         self.result.push_str(&self.temp_buf);
     }
 }
 
-// Name sanitation. LLVM will happily accept identifiers with weird names, but
-// gas doesn't!
-// gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
-//
-// returns true if an underscore must be added at the start
-pub fn sanitize(result: &mut String, s: &str) -> bool {
-    for c in s.chars() {
-        match c {
-            // Escape these with $ sequences
-            '@' => result.push_str("$SP$"),
-            '*' => result.push_str("$BP$"),
-            '&' => result.push_str("$RF$"),
-            '<' => result.push_str("$LT$"),
-            '>' => result.push_str("$GT$"),
-            '(' => result.push_str("$LP$"),
-            ')' => result.push_str("$RP$"),
-            ',' => result.push_str("$C$"),
-
-            // '.' doesn't occur in types and functions, so reuse it
-            // for ':' and '-'
-            '-' | ':' => result.push('.'),
-
-            // These are legal symbols
-            'a'..='z' | 'A'..='Z' | '0'..='9' | '_' | '.' | '$' => result.push(c),
-
-            _ => {
-                result.push('$');
-                for c in c.escape_unicode().skip(1) {
-                    match c {
-                        '{' => {}
-                        '}' => result.push('$'),
-                        c => result.push(c),
-                    }
-                }
-            }
-        }
+impl ItemPathBuffer for SymbolPathBuffer {
+    fn root_mode(&self) -> &RootMode {
+        const ABSOLUTE: &RootMode = &RootMode::Absolute;
+        ABSOLUTE
     }
 
-    // Underscore-qualify anything that didn't start as an ident.
-    !result.is_empty() && result.as_bytes()[0] != '_' as u8
-        && !(result.as_bytes()[0] as char).is_xid_start()
+    fn push(&mut self, text: &str) {
+        self.sanitize_and_append(text);
+    }
 }
diff --git a/src/librustc_cratesio_shim/Cargo.toml b/src/librustc_cratesio_shim/Cargo.toml
index b8e494e4040ec..6bdfbe09354b4 100644
--- a/src/librustc_cratesio_shim/Cargo.toml
+++ b/src/librustc_cratesio_shim/Cargo.toml
@@ -15,6 +15,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_cratesio_shim"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 crate-type = ["dylib"]
diff --git a/src/librustc_cratesio_shim/src/lib.rs b/src/librustc_cratesio_shim/src/lib.rs
index 4024087f4d3ef..4c170f4f5f6f9 100644
--- a/src/librustc_cratesio_shim/src/lib.rs
+++ b/src/librustc_cratesio_shim/src/lib.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 // See Cargo.toml for a comment explaining this crate.
 #![allow(unused_extern_crates)]
 
diff --git a/src/librustc_data_structures/Cargo.toml b/src/librustc_data_structures/Cargo.toml
index 1754376a5d7f9..f781952d4172c 100644
--- a/src/librustc_data_structures/Cargo.toml
+++ b/src/librustc_data_structures/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_data_structures"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_data_structures"
@@ -16,8 +17,8 @@ serialize = { path = "../libserialize" }
 graphviz = { path = "../libgraphviz" }
 cfg-if = "0.1.2"
 stable_deref_trait = "1.0.0"
-rustc-rayon = "0.1.1"
-rustc-rayon-core = "0.1.1"
+rayon = { version = "0.1.1", package = "rustc-rayon" }
+rayon-core = { version = "0.1.1", package = "rustc-rayon-core" }
 rustc-hash = "1.0.1"
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
 
diff --git a/src/librustc_data_structures/base_n.rs b/src/librustc_data_structures/base_n.rs
index c9c1933f25b2b..f1bd3f03aef8d 100644
--- a/src/librustc_data_structures/base_n.rs
+++ b/src/librustc_data_structures/base_n.rs
@@ -1,4 +1,4 @@
-/// Convert unsigned integers into a string representation with some base.
+/// Converts unsigned integers into a string representation with some base.
 /// Bases up to and including 36 can be used for case-insensitive things.
 
 use std::str;
diff --git a/src/librustc_data_structures/bit_set.rs b/src/librustc_data_structures/bit_set.rs
index 8adfe3749af8e..ff7964646d608 100644
--- a/src/librustc_data_structures/bit_set.rs
+++ b/src/librustc_data_structures/bit_set.rs
@@ -1,4 +1,4 @@
-use indexed_vec::{Idx, IndexVec};
+use crate::indexed_vec::{Idx, IndexVec};
 use smallvec::SmallVec;
 use std::fmt;
 use std::iter;
@@ -27,7 +27,7 @@ pub struct BitSet<T: Idx> {
 }
 
 impl<T: Idx> BitSet<T> {
-    /// Create a new, empty bitset with a given `domain_size`.
+    /// Creates a new, empty bitset with a given `domain_size`.
     #[inline]
     pub fn new_empty(domain_size: usize) -> BitSet<T> {
         let num_words = num_words(domain_size);
@@ -38,7 +38,7 @@ impl<T: Idx> BitSet<T> {
         }
     }
 
-    /// Create a new, filled bitset with a given `domain_size`.
+    /// Creates a new, filled bitset with a given `domain_size`.
     #[inline]
     pub fn new_filled(domain_size: usize) -> BitSet<T> {
         let num_words = num_words(domain_size);
@@ -51,7 +51,7 @@ impl<T: Idx> BitSet<T> {
         result
     }
 
-    /// Get the domain size.
+    /// Gets the domain size.
     pub fn domain_size(&self) -> usize {
         self.domain_size
     }
@@ -85,7 +85,7 @@ impl<T: Idx> BitSet<T> {
         self.words.iter().map(|e| e.count_ones() as usize).sum()
     }
 
-    /// True if `self` contains `elem`.
+    /// Returns `true` if `self` contains `elem`.
     #[inline]
     pub fn contains(&self, elem: T) -> bool {
         assert!(elem.index() < self.domain_size);
@@ -106,7 +106,7 @@ impl<T: Idx> BitSet<T> {
         self.words.iter().all(|a| *a == 0)
     }
 
-    /// Insert `elem`. Returns true if the set has changed.
+    /// Insert `elem`. Returns whether the set has changed.
     #[inline]
     pub fn insert(&mut self, elem: T) -> bool {
         assert!(elem.index() < self.domain_size);
@@ -126,7 +126,7 @@ impl<T: Idx> BitSet<T> {
         self.clear_excess_bits();
     }
 
-    /// Returns true if the set has changed.
+    /// Returns `true` if the set has changed.
     #[inline]
     pub fn remove(&mut self, elem: T) -> bool {
         assert!(elem.index() < self.domain_size);
@@ -138,26 +138,26 @@ impl<T: Idx> BitSet<T> {
         new_word != word
     }
 
-    /// Set `self = self | other` and return true if `self` changed
+    /// Sets `self = self | other` and returns `true` if `self` changed
     /// (i.e., if new bits were added).
     pub fn union(&mut self, other: &impl UnionIntoBitSet<T>) -> bool {
         other.union_into(self)
     }
 
-    /// Set `self = self - other` and return true if `self` changed.
+    /// Sets `self = self - other` and returns `true` if `self` changed.
     /// (i.e., if any bits were removed).
     pub fn subtract(&mut self, other: &impl SubtractFromBitSet<T>) -> bool {
         other.subtract_from(self)
     }
 
-    /// Set `self = self & other` and return true if `self` changed.
+    /// Sets `self = self & other` and return `true` if `self` changed.
     /// (i.e., if any bits were removed).
     pub fn intersect(&mut self, other: &BitSet<T>) -> bool {
         assert_eq!(self.domain_size, other.domain_size);
         bitwise(&mut self.words, &other.words, |a, b| { a & b })
     }
 
-    /// Get a slice of the underlying words.
+    /// Gets a slice of the underlying words.
     pub fn words(&self) -> &[Word] {
         &self.words
     }
@@ -208,7 +208,7 @@ impl<T: Idx> SubtractFromBitSet<T> for BitSet<T> {
 }
 
 impl<T: Idx> fmt::Debug for BitSet<T> {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         w.debug_list()
          .entries(self.iter())
          .finish()
@@ -366,7 +366,7 @@ impl<T: Idx> SparseBitSet<T> {
         dense
     }
 
-    fn iter(&self) -> slice::Iter<T> {
+    fn iter(&self) -> slice::Iter<'_, T> {
         self.elems.iter()
     }
 }
@@ -536,7 +536,7 @@ impl<T: Idx> HybridBitSet<T> {
         }
     }
 
-    pub fn iter(&self) -> HybridIter<T> {
+    pub fn iter(&self) -> HybridIter<'_, T> {
         match self {
             HybridBitSet::Sparse(sparse) => HybridIter::Sparse(sparse.iter()),
             HybridBitSet::Dense(dense) => HybridIter::Dense(dense.iter()),
@@ -611,7 +611,7 @@ impl<T: Idx> GrowableBitSet<T> {
         GrowableBitSet { bit_set: BitSet::new_empty(bits) }
     }
 
-    /// Returns true if the set has changed.
+    /// Returns `true` if the set has changed.
     #[inline]
     pub fn insert(&mut self, elem: T) -> bool {
         self.ensure(elem.index() + 1);
@@ -645,7 +645,7 @@ pub struct BitMatrix<R: Idx, C: Idx> {
 }
 
 impl<R: Idx, C: Idx> BitMatrix<R, C> {
-    /// Create a new `rows x columns` matrix, initially empty.
+    /// Creates a new `rows x columns` matrix, initially empty.
     pub fn new(num_rows: usize, num_columns: usize) -> BitMatrix<R, C> {
         // For every element, we need one bit for every other
         // element. Round up to an even number of words.
@@ -668,7 +668,7 @@ impl<R: Idx, C: Idx> BitMatrix<R, C> {
     /// Sets the cell at `(row, column)` to true. Put another way, insert
     /// `column` to the bitset for `row`.
     ///
-    /// Returns true if this changed the matrix, and false otherwise.
+    /// Returns `true` if this changed the matrix.
     pub fn insert(&mut self, row: R, column: C) -> bool {
         assert!(row.index() < self.num_rows && column.index() < self.num_columns);
         let (start, _) = self.range(row);
@@ -691,7 +691,7 @@ impl<R: Idx, C: Idx> BitMatrix<R, C> {
         (self.words[start + word_index] & mask) != 0
     }
 
-    /// Returns those indices that are true in rows `a` and `b`.  This
+    /// Returns those indices that are true in rows `a` and `b`. This
     /// is an O(n) operation where `n` is the number of elements
     /// (somewhat independent from the actual size of the
     /// intersection, in particular).
@@ -715,8 +715,8 @@ impl<R: Idx, C: Idx> BitMatrix<R, C> {
         result
     }
 
-    /// Add the bits from row `read` to the bits from row `write`,
-    /// return true if anything changed.
+    /// Adds the bits from row `read` to the bits from row `write`, and
+    /// returns `true` if anything changed.
     ///
     /// This is used when computing transitive reachability because if
     /// you have an edge `write -> read`, because in that case
@@ -772,7 +772,7 @@ where
 }
 
 impl<R: Idx, C: Idx> SparseBitMatrix<R, C> {
-    /// Create a new empty sparse bit matrix with no rows or columns.
+    /// Creates a new empty sparse bit matrix with no rows or columns.
     pub fn new(num_columns: usize) -> Self {
         Self {
             num_columns,
@@ -793,7 +793,7 @@ impl<R: Idx, C: Idx> SparseBitMatrix<R, C> {
     /// Sets the cell at `(row, column)` to true. Put another way, insert
     /// `column` to the bitset for `row`.
     ///
-    /// Returns true if this changed the matrix, and false otherwise.
+    /// Returns `true` if this changed the matrix.
     pub fn insert(&mut self, row: R, column: C) -> bool {
         self.ensure_row(row).insert(column)
     }
@@ -806,8 +806,8 @@ impl<R: Idx, C: Idx> SparseBitMatrix<R, C> {
         self.row(row).map_or(false, |r| r.contains(column))
     }
 
-    /// Add the bits from row `read` to the bits from row `write`,
-    /// return true if anything changed.
+    /// Adds the bits from row `read` to the bits from row `write`, and
+    /// returns `true` if anything changed.
     ///
     /// This is used when computing transitive reachability because if
     /// you have an edge `write -> read`, because in that case
diff --git a/src/librustc_data_structures/fingerprint.rs b/src/librustc_data_structures/fingerprint.rs
index 2e596ca3e44f1..c4c0db5801209 100644
--- a/src/librustc_data_structures/fingerprint.rs
+++ b/src/librustc_data_structures/fingerprint.rs
@@ -1,5 +1,5 @@
+use crate::stable_hasher;
 use std::mem;
-use stable_hasher;
 use serialize;
 use serialize::opaque::{EncodeResult, Encoder, Decoder};
 
@@ -70,7 +70,7 @@ impl Fingerprint {
 }
 
 impl ::std::fmt::Display for Fingerprint {
-    fn fmt(&self, formatter: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, formatter: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         write!(formatter, "{:x}-{:x}", self.0, self.1)
     }
 }
diff --git a/src/librustc_data_structures/flock.rs b/src/librustc_data_structures/flock.rs
index 2dea249f1c07c..255c5fd7fe7ec 100644
--- a/src/librustc_data_structures/flock.rs
+++ b/src/librustc_data_structures/flock.rs
@@ -14,12 +14,9 @@ cfg_if! {
     if #[cfg(unix)] {
         use std::ffi::{CString, OsStr};
         use std::os::unix::prelude::*;
-        use libc;
 
         #[cfg(any(target_os = "linux", target_os = "android"))]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_type: libc::c_short,
@@ -35,8 +32,6 @@ cfg_if! {
 
         #[cfg(target_os = "freebsd")]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_start: libc::off_t,
@@ -53,8 +48,6 @@ cfg_if! {
                   target_os = "netbsd",
                   target_os = "openbsd"))]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_start: libc::off_t,
@@ -70,8 +63,6 @@ cfg_if! {
 
         #[cfg(target_os = "haiku")]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_type: libc::c_short,
@@ -87,8 +78,6 @@ cfg_if! {
 
         #[cfg(any(target_os = "macos", target_os = "ios"))]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_start: libc::off_t,
@@ -104,8 +93,6 @@ cfg_if! {
 
         #[cfg(target_os = "solaris")]
         mod os {
-            use libc;
-
             #[repr(C)]
             pub struct flock {
                 pub l_type: libc::c_short,
diff --git a/src/librustc_data_structures/graph/dominators/mod.rs b/src/librustc_data_structures/graph/dominators/mod.rs
index 536efffbb22f4..aaed41d9fa362 100644
--- a/src/librustc_data_structures/graph/dominators/mod.rs
+++ b/src/librustc_data_structures/graph/dominators/mod.rs
@@ -117,7 +117,7 @@ impl<Node: Idx> Dominators<Node> {
         self.immediate_dominators[node].unwrap()
     }
 
-    pub fn dominators(&self, node: Node) -> Iter<Node> {
+    pub fn dominators(&self, node: Node) -> Iter<'_, Node> {
         assert!(self.is_reachable(node), "node {:?} is not reachable", node);
         Iter {
             dominators: self,
@@ -136,7 +136,7 @@ impl<Node: Idx> Dominators<Node> {
     }
 }
 
-pub struct Iter<'dom, Node: Idx + 'dom> {
+pub struct Iter<'dom, Node: Idx> {
     dominators: &'dom Dominators<Node>,
     node: Option<Node>,
 }
@@ -171,7 +171,7 @@ impl<Node: Idx> DominatorTree<Node> {
 }
 
 impl<Node: Idx> fmt::Debug for DominatorTree<Node> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(
             &DominatorTreeNode {
                 tree: self,
@@ -188,7 +188,7 @@ struct DominatorTreeNode<'tree, Node: Idx> {
 }
 
 impl<'tree, Node: Idx> fmt::Debug for DominatorTreeNode<'tree, Node> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         let subtrees: Vec<_> = self.tree
             .children(self.node)
             .iter()
diff --git a/src/librustc_data_structures/graph/implementation/mod.rs b/src/librustc_data_structures/graph/implementation/mod.rs
index 0768873f83626..de4b1bcd0c2a1 100644
--- a/src/librustc_data_structures/graph/implementation/mod.rs
+++ b/src/librustc_data_structures/graph/implementation/mod.rs
@@ -14,16 +14,16 @@
 //! stored. The edges are stored in a central array, but they are also
 //! threaded onto two linked lists for each node, one for incoming edges
 //! and one for outgoing edges. Note that every edge is a member of some
-//! incoming list and some outgoing list.  Basically you can load the
+//! incoming list and some outgoing list. Basically you can load the
 //! first index of the linked list from the node data structures (the
 //! field `first_edge`) and then, for each edge, load the next index from
 //! the field `next_edge`). Each of those fields is an array that should
 //! be indexed by the direction (see the type `Direction`).
 
-use bit_set::BitSet;
+use crate::bit_set::BitSet;
+use crate::snapshot_vec::{SnapshotVec, SnapshotVecDelegate};
 use std::fmt::Debug;
 use std::usize;
-use snapshot_vec::{SnapshotVec, SnapshotVecDelegate};
 
 #[cfg(test)]
 mod tests;
@@ -79,7 +79,7 @@ pub const OUTGOING: Direction = Direction { repr: 0 };
 pub const INCOMING: Direction = Direction { repr: 1 };
 
 impl NodeIndex {
-    /// Returns unique id (unique with respect to the graph holding associated node).
+    /// Returns unique ID (unique with respect to the graph holding associated node).
     pub fn node_id(self) -> usize {
         self.0
     }
@@ -212,15 +212,19 @@ impl<N: Debug, E: Debug> Graph<N, E> {
             .all(|(edge_idx, edge)| f(edge_idx, edge))
     }
 
-    pub fn outgoing_edges(&self, source: NodeIndex) -> AdjacentEdges<N, E> {
+    pub fn outgoing_edges(&self, source: NodeIndex) -> AdjacentEdges<'_, N, E> {
         self.adjacent_edges(source, OUTGOING)
     }
 
-    pub fn incoming_edges(&self, source: NodeIndex) -> AdjacentEdges<N, E> {
+    pub fn incoming_edges(&self, source: NodeIndex) -> AdjacentEdges<'_, N, E> {
         self.adjacent_edges(source, INCOMING)
     }
 
-    pub fn adjacent_edges(&self, source: NodeIndex, direction: Direction) -> AdjacentEdges<N, E> {
+    pub fn adjacent_edges(
+        &self,
+        source: NodeIndex,
+        direction: Direction
+    ) -> AdjacentEdges<'_, N, E> {
         let first_edge = self.node(source).first_edge[direction.repr];
         AdjacentEdges {
             graph: self,
@@ -291,11 +295,7 @@ impl<N: Debug, E: Debug> Graph<N, E> {
 
 // # Iterators
 
-pub struct AdjacentEdges<'g, N, E>
-where
-    N: 'g,
-    E: 'g,
-{
+pub struct AdjacentEdges<'g, N, E> {
     graph: &'g Graph<N, E>,
     direction: Direction,
     next: EdgeIndex,
@@ -331,11 +331,7 @@ impl<'g, N: Debug, E: Debug> Iterator for AdjacentEdges<'g, N, E> {
     }
 }
 
-pub struct DepthFirstTraversal<'g, N, E>
-where
-    N: 'g,
-    E: 'g,
-{
+pub struct DepthFirstTraversal<'g, N, E> {
     graph: &'g Graph<N, E>,
     stack: Vec<NodeIndex>,
     visited: BitSet<usize>,
diff --git a/src/librustc_data_structures/graph/implementation/tests.rs b/src/librustc_data_structures/graph/implementation/tests.rs
index a7a2504239610..82c6da3f42711 100644
--- a/src/librustc_data_structures/graph/implementation/tests.rs
+++ b/src/librustc_data_structures/graph/implementation/tests.rs
@@ -1,4 +1,4 @@
-use graph::implementation::*;
+use crate::graph::implementation::*;
 use std::fmt::Debug;
 
 type TestGraph = Graph<&'static str, &'static str>;
diff --git a/src/librustc_data_structures/graph/scc/mod.rs b/src/librustc_data_structures/graph/scc/mod.rs
index baab377ef1276..24c5448639e7d 100644
--- a/src/librustc_data_structures/graph/scc/mod.rs
+++ b/src/librustc_data_structures/graph/scc/mod.rs
@@ -3,9 +3,9 @@
 //! node in the graph. This uses Tarjan's algorithm that completes in
 //! O(n) time.
 
-use fx::FxHashSet;
-use graph::{DirectedGraph, WithNumNodes, WithSuccessors};
-use indexed_vec::{Idx, IndexVec};
+use crate::fx::FxHashSet;
+use crate::graph::{DirectedGraph, WithNumNodes, WithSuccessors};
+use crate::indexed_vec::{Idx, IndexVec};
 use std::ops::Range;
 
 mod test;
@@ -93,7 +93,7 @@ impl<S: Idx> SccData<S> {
     }
 }
 
-struct SccsConstruction<'c, G: DirectedGraph + WithNumNodes + WithSuccessors + 'c, S: Idx> {
+struct SccsConstruction<'c, G: DirectedGraph + WithNumNodes + WithSuccessors, S: Idx> {
     graph: &'c G,
 
     /// The state of each node; used during walk to record the stack
@@ -200,7 +200,7 @@ where
         }
     }
 
-    /// Visit a node during the DFS. We first examine its current
+    /// Visits a node during the DFS. We first examine its current
     /// state -- if it is not yet visited (`NotVisited`), we can push
     /// it onto the stack and start walking its successors.
     ///
diff --git a/src/librustc_data_structures/graph/scc/test.rs b/src/librustc_data_structures/graph/scc/test.rs
index e23cb1348b015..da3a1ceefe94b 100644
--- a/src/librustc_data_structures/graph/scc/test.rs
+++ b/src/librustc_data_structures/graph/scc/test.rs
@@ -1,6 +1,6 @@
 #![cfg(test)]
 
-use graph::test::TestGraph;
+use crate::graph::test::TestGraph;
 use super::*;
 
 #[test]
diff --git a/src/librustc_data_structures/graph/test.rs b/src/librustc_data_structures/graph/test.rs
index 3d482e448bdb7..b390c41957294 100644
--- a/src/librustc_data_structures/graph/test.rs
+++ b/src/librustc_data_structures/graph/test.rs
@@ -1,4 +1,4 @@
-use fx::FxHashMap;
+use crate::fx::FxHashMap;
 use std::cmp::max;
 use std::slice;
 use std::iter;
diff --git a/src/librustc_data_structures/indexed_vec.rs b/src/librustc_data_structures/indexed_vec.rs
index 8d8fbe588a021..09aec50e4bb11 100644
--- a/src/librustc_data_structures/indexed_vec.rs
+++ b/src/librustc_data_structures/indexed_vec.rs
@@ -12,7 +12,7 @@ use rustc_serialize as serialize;
 
 /// Represents some newtyped `usize` wrapper.
 ///
-/// (purpose: avoid mixing indexes for different bitvector domains.)
+/// Purpose: avoid mixing indexes for different bitvector domains.
 pub trait Idx: Copy + 'static + Ord + Debug + Hash {
     fn new(idx: usize) -> Self;
 
@@ -144,19 +144,19 @@ macro_rules! newtype_index {
                 unsafe { $type { private: value } }
             }
 
-            /// Extract value of this index as an integer.
+            /// Extracts the value of this index as an integer.
             #[inline]
             $v fn index(self) -> usize {
                 self.as_usize()
             }
 
-            /// Extract value of this index as a usize.
+            /// Extracts the value of this index as a `u32`.
             #[inline]
             $v fn as_u32(self) -> u32 {
                 self.private
             }
 
-            /// Extract value of this index as a u32.
+            /// Extracts the value of this index as a `usize`.
             #[inline]
             $v fn as_usize(self) -> usize {
                 self.as_u32() as usize
@@ -257,7 +257,7 @@ macro_rules! newtype_index {
      @type         [$type:ident]
      @debug_format [$debug_format:tt]) => (
         impl ::std::fmt::Debug for $type {
-            fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+            fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                 write!(fmt, $debug_format, self.as_u32())
             }
         }
@@ -495,7 +495,7 @@ impl<I: Idx, T: serialize::Decodable> serialize::Decodable for IndexVec<I, T> {
 }
 
 impl<I: Idx, T: fmt::Debug> fmt::Debug for IndexVec<I, T> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&self.raw, fmt)
     }
 }
@@ -573,7 +573,7 @@ impl<I: Idx, T> IndexVec<I, T> {
     }
 
     #[inline]
-    pub fn iter(&self) -> slice::Iter<T> {
+    pub fn iter(&self) -> slice::Iter<'_, T> {
         self.raw.iter()
     }
 
@@ -589,7 +589,7 @@ impl<I: Idx, T> IndexVec<I, T> {
     }
 
     #[inline]
-    pub fn iter_mut(&mut self) -> slice::IterMut<T> {
+    pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
         self.raw.iter_mut()
     }
 
@@ -641,7 +641,7 @@ impl<I: Idx, T> IndexVec<I, T> {
         self.raw.get_mut(index.index())
     }
 
-    /// Return mutable references to two distinct elements, a and b. Panics if a == b.
+    /// Returns mutable references to two distinct elements, a and b. Panics if a == b.
     #[inline]
     pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
         let (ai, bi) = (a.index(), b.index());
diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index ec71f5158948c..2bfb1b24a81b9 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -6,9 +6,7 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://www.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(in_band_lifetimes)]
 #![feature(unboxed_closures)]
@@ -26,23 +24,16 @@
 #![cfg_attr(unix, feature(libc))]
 #![cfg_attr(test, feature(test))]
 
-extern crate core;
-extern crate ena;
+#![deny(rust_2018_idioms)]
+
 #[macro_use]
 extern crate log;
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
 #[cfg(unix)]
 extern crate libc;
-extern crate parking_lot;
 #[macro_use]
 extern crate cfg_if;
-extern crate stable_deref_trait;
-extern crate rustc_rayon as rayon;
-extern crate rustc_rayon_core as rayon_core;
-extern crate rustc_hash;
-extern crate serialize;
-extern crate graphviz;
-extern crate smallvec;
 
 // See librustc_cratesio_shim/Cargo.toml for a comment explaining this.
 #[allow(unused_extern_crates)]
@@ -50,6 +41,12 @@ extern crate rustc_cratesio_shim;
 
 pub use rustc_serialize::hex::ToHex;
 
+#[inline(never)]
+#[cold]
+pub fn cold_path<F: FnOnce() -> R, R>(f: F) -> R {
+      f()
+}
+
 #[macro_export]
 macro_rules! likely {
       ($e:expr) => {
diff --git a/src/librustc_data_structures/macros.rs b/src/librustc_data_structures/macros.rs
index a661f0c78ab5d..af1f2910461ec 100644
--- a/src/librustc_data_structures/macros.rs
+++ b/src/librustc_data_structures/macros.rs
@@ -1,7 +1,8 @@
 /// A simple static assertion macro. The first argument should be a unique
 /// ALL_CAPS identifier that describes the condition.
 #[macro_export]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(type_ascription))]
 macro_rules! static_assert {
     ($name:ident: $test:expr) => {
         // Use the bool to access an array such that if the bool is false, the access
diff --git a/src/librustc_data_structures/obligation_forest/README.md b/src/librustc_data_structures/obligation_forest/README.md
deleted file mode 100644
index 982a2bacce164..0000000000000
--- a/src/librustc_data_structures/obligation_forest/README.md
+++ /dev/null
@@ -1,81 +0,0 @@
-The `ObligationForest` is a utility data structure used in trait
-matching to track the set of outstanding obligations (those not yet
-resolved to success or error). It also tracks the "backtrace" of each
-pending obligation (why we are trying to figure this out in the first
-place).
-
-### External view
-
-`ObligationForest` supports two main public operations (there are a
-few others not discussed here):
-
-1. Add a new root obligations (`push_tree`).
-2. Process the pending obligations (`process_obligations`).
-
-When a new obligation `N` is added, it becomes the root of an
-obligation tree. This tree can also carry some per-tree state `T`,
-which is given at the same time. This tree is a singleton to start, so
-`N` is both the root and the only leaf. Each time the
-`process_obligations` method is called, it will invoke its callback
-with every pending obligation (so that will include `N`, the first
-time). The callback also receives a (mutable) reference to the
-per-tree state `T`. The callback should process the obligation `O`
-that it is given and return one of three results:
-
-- `Ok(None)` -> ambiguous result. Obligation was neither a success
-  nor a failure. It is assumed that further attempts to process the
-  obligation will yield the same result unless something in the
-  surrounding environment changes.
-- `Ok(Some(C))` - the obligation was *shallowly successful*. The
-  vector `C` is a list of subobligations. The meaning of this is that
-  `O` was successful on the assumption that all the obligations in `C`
-  are also successful. Therefore, `O` is only considered a "true"
-  success if `C` is empty. Otherwise, `O` is put into a suspended
-  state and the obligations in `C` become the new pending
-  obligations. They will be processed the next time you call
-  `process_obligations`.
-- `Err(E)` -> obligation failed with error `E`. We will collect this
-  error and return it from `process_obligations`, along with the
-  "backtrace" of obligations (that is, the list of obligations up to
-  and including the root of the failed obligation). No further
-  obligations from that same tree will be processed, since the tree is
-  now considered to be in error.
-
-When the call to `process_obligations` completes, you get back an `Outcome`,
-which includes three bits of information:
-
-- `completed`: a list of obligations where processing was fully
-  completed without error (meaning that all transitive subobligations
-  have also been completed). So, for example, if the callback from
-  `process_obligations` returns `Ok(Some(C))` for some obligation `O`,
-  then `O` will be considered completed right away if `C` is the
-  empty vector. Otherwise it will only be considered completed once
-  all the obligations in `C` have been found completed.
-- `errors`: a list of errors that occurred and associated backtraces
-  at the time of error, which can be used to give context to the user.
-- `stalled`: if true, then none of the existing obligations were
-  *shallowly successful* (that is, no callback returned `Ok(Some(_))`).
-  This implies that all obligations were either errors or returned an
-  ambiguous result, which means that any further calls to
-  `process_obligations` would simply yield back further ambiguous
-  results. This is used by the `FulfillmentContext` to decide when it
-  has reached a steady state.
-
-#### Snapshots
-
-The `ObligationForest` supports a limited form of snapshots; see
-`start_snapshot`; `commit_snapshot`; and `rollback_snapshot`. In
-particular, you can use a snapshot to roll back new root
-obligations. However, it is an error to attempt to
-`process_obligations` during a snapshot.
-
-### Implementation details
-
-For the most part, comments specific to the implementation are in the
-code.  This file only contains a very high-level overview. Basically,
-the forest is stored in a vector. Each element of the vector is a node
-in some tree. Each node in the vector has the index of an (optional)
-parent and (for convenience) its root (which may be itself). It also
-has a current state, described by `NodeState`. After each
-processing step, we compress the vector to remove completed and error
-nodes, which aren't needed anymore.
diff --git a/src/librustc_data_structures/obligation_forest/graphviz.rs b/src/librustc_data_structures/obligation_forest/graphviz.rs
index c2e3938b305d2..a0363e165e049 100644
--- a/src/librustc_data_structures/obligation_forest/graphviz.rs
+++ b/src/librustc_data_structures/obligation_forest/graphviz.rs
@@ -1,5 +1,5 @@
+use crate::obligation_forest::{ForestObligation, ObligationForest};
 use graphviz as dot;
-use obligation_forest::{ForestObligation, ObligationForest};
 use std::env::var_os;
 use std::fs::File;
 use std::path::Path;
@@ -7,8 +7,8 @@ use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering;
 
 impl<O: ForestObligation> ObligationForest<O> {
-    /// Create a graphviz representation of the obligation forest.  Given a directory this will
-    /// create files with name of the format `<counter>_<description>.gv`.  The counter is
+    /// Creates a graphviz representation of the obligation forest. Given a directory this will
+    /// create files with name of the format `<counter>_<description>.gv`. The counter is
     /// global and is maintained internally.
     ///
     /// Calling this will do nothing unless the environment variable
@@ -41,22 +41,22 @@ impl<'a, O: ForestObligation + 'a> dot::Labeller<'a> for &'a ObligationForest<O>
     type Node = usize;
     type Edge = (usize, usize);
 
-    fn graph_id(&self) -> dot::Id {
+    fn graph_id(&self) -> dot::Id<'_> {
         dot::Id::new("trait_obligation_forest").unwrap()
     }
 
-    fn node_id(&self, index: &Self::Node) -> dot::Id {
+    fn node_id(&self, index: &Self::Node) -> dot::Id<'_> {
         dot::Id::new(format!("obligation_{}", index)).unwrap()
     }
 
-    fn node_label(&self, index: &Self::Node) -> dot::LabelText {
+    fn node_label(&self, index: &Self::Node) -> dot::LabelText<'_> {
         let node = &self.nodes[*index];
         let label = format!("{:?} ({:?})", node.obligation.as_predicate(), node.state.get());
 
         dot::LabelText::LabelStr(label.into())
     }
 
-    fn edge_label(&self, (_index_source, _index_target): &Self::Edge) -> dot::LabelText {
+    fn edge_label(&self, (_index_source, _index_target): &Self::Edge) -> dot::LabelText<'_> {
         dot::LabelText::LabelStr("".into())
     }
 }
@@ -65,11 +65,11 @@ impl<'a, O: ForestObligation + 'a> dot::GraphWalk<'a> for &'a ObligationForest<O
     type Node = usize;
     type Edge = (usize, usize);
 
-    fn nodes(&self) -> dot::Nodes<Self::Node> {
+    fn nodes(&self) -> dot::Nodes<'_, Self::Node> {
         (0..self.nodes.len()).collect()
     }
 
-    fn edges(&self) -> dot::Edges<Self::Edge> {
+    fn edges(&self) -> dot::Edges<'_, Self::Edge> {
         (0..self.nodes.len())
             .flat_map(|i| {
                 let node = &self.nodes[i];
diff --git a/src/librustc_data_structures/obligation_forest/mod.rs b/src/librustc_data_structures/obligation_forest/mod.rs
index 59497f0df18e9..4490e5f86d2bd 100644
--- a/src/librustc_data_structures/obligation_forest/mod.rs
+++ b/src/librustc_data_structures/obligation_forest/mod.rs
@@ -1,11 +1,86 @@
 //! The `ObligationForest` is a utility data structure used in trait
-//! matching to track the set of outstanding obligations (those not
-//! yet resolved to success or error). It also tracks the "backtrace"
-//! of each pending obligation (why we are trying to figure this out
-//! in the first place). See README.md for a general overview of how
-//! to use this class.
-
-use fx::{FxHashMap, FxHashSet};
+//! matching to track the set of outstanding obligations (those not yet
+//! resolved to success or error). It also tracks the "backtrace" of each
+//! pending obligation (why we are trying to figure this out in the first
+//! place).
+//!
+//! ### External view
+//!
+//! `ObligationForest` supports two main public operations (there are a
+//! few others not discussed here):
+//!
+//! 1. Add a new root obligations (`push_tree`).
+//! 2. Process the pending obligations (`process_obligations`).
+//!
+//! When a new obligation `N` is added, it becomes the root of an
+//! obligation tree. This tree can also carry some per-tree state `T`,
+//! which is given at the same time. This tree is a singleton to start, so
+//! `N` is both the root and the only leaf. Each time the
+//! `process_obligations` method is called, it will invoke its callback
+//! with every pending obligation (so that will include `N`, the first
+//! time). The callback also receives a (mutable) reference to the
+//! per-tree state `T`. The callback should process the obligation `O`
+//! that it is given and return one of three results:
+//!
+//! - `Ok(None)` -> ambiguous result. Obligation was neither a success
+//!   nor a failure. It is assumed that further attempts to process the
+//!   obligation will yield the same result unless something in the
+//!   surrounding environment changes.
+//! - `Ok(Some(C))` - the obligation was *shallowly successful*. The
+//!   vector `C` is a list of subobligations. The meaning of this is that
+//!   `O` was successful on the assumption that all the obligations in `C`
+//!   are also successful. Therefore, `O` is only considered a "true"
+//!   success if `C` is empty. Otherwise, `O` is put into a suspended
+//!   state and the obligations in `C` become the new pending
+//!   obligations. They will be processed the next time you call
+//!   `process_obligations`.
+//! - `Err(E)` -> obligation failed with error `E`. We will collect this
+//!   error and return it from `process_obligations`, along with the
+//!   "backtrace" of obligations (that is, the list of obligations up to
+//!   and including the root of the failed obligation). No further
+//!   obligations from that same tree will be processed, since the tree is
+//!   now considered to be in error.
+//!
+//! When the call to `process_obligations` completes, you get back an `Outcome`,
+//! which includes three bits of information:
+//!
+//! - `completed`: a list of obligations where processing was fully
+//!   completed without error (meaning that all transitive subobligations
+//!   have also been completed). So, for example, if the callback from
+//!   `process_obligations` returns `Ok(Some(C))` for some obligation `O`,
+//!   then `O` will be considered completed right away if `C` is the
+//!   empty vector. Otherwise it will only be considered completed once
+//!   all the obligations in `C` have been found completed.
+//! - `errors`: a list of errors that occurred and associated backtraces
+//!   at the time of error, which can be used to give context to the user.
+//! - `stalled`: if true, then none of the existing obligations were
+//!   *shallowly successful* (that is, no callback returned `Ok(Some(_))`).
+//!   This implies that all obligations were either errors or returned an
+//!   ambiguous result, which means that any further calls to
+//!   `process_obligations` would simply yield back further ambiguous
+//!   results. This is used by the `FulfillmentContext` to decide when it
+//!   has reached a steady state.
+//!
+//! #### Snapshots
+//!
+//! The `ObligationForest` supports a limited form of snapshots; see
+//! `start_snapshot`, `commit_snapshot`, and `rollback_snapshot`. In
+//! particular, you can use a snapshot to roll back new root
+//! obligations. However, it is an error to attempt to
+//! `process_obligations` during a snapshot.
+//!
+//! ### Implementation details
+//!
+//! For the most part, comments specific to the implementation are in the
+//! code. This file only contains a very high-level overview. Basically,
+//! the forest is stored in a vector. Each element of the vector is a node
+//! in some tree. Each node in the vector has the index of an (optional)
+//! parent and (for convenience) its root (which may be itself). It also
+//! has a current state, described by `NodeState`. After each
+//! processing step, we compress the vector to remove completed and error
+//! nodes, which aren't needed anymore.
+
+use crate::fx::{FxHashMap, FxHashSet};
 
 use std::cell::Cell;
 use std::collections::hash_map::Entry;
@@ -88,7 +163,7 @@ pub struct ObligationForest<O: ForestObligation> {
 
     obligation_tree_id_generator: ObligationTreeIdGenerator,
 
-    /// Per tree error cache.  This is used to deduplicate errors,
+    /// Per tree error cache. This is used to deduplicate errors,
     /// which is necessary to avoid trait resolution overflow in
     /// some cases.
     ///
@@ -193,13 +268,13 @@ impl<O: ForestObligation> ObligationForest<O> {
         }
     }
 
-    /// Return the total number of nodes in the forest that have not
+    /// Returns the total number of nodes in the forest that have not
     /// yet been fully resolved.
     pub fn len(&self) -> usize {
         self.nodes.len()
     }
 
-    /// Registers an obligation
+    /// Registers an obligation.
     ///
     /// This CAN be done in a snapshot
     pub fn register_obligation(&mut self, obligation: O) {
@@ -266,7 +341,7 @@ impl<O: ForestObligation> ObligationForest<O> {
         }
     }
 
-    /// Convert all remaining obligations to the given error.
+    /// Converts all remaining obligations to the given error.
     ///
     /// This cannot be done during a snapshot.
     pub fn to_errors<E: Clone>(&mut self, error: E) -> Vec<Error<O, E>> {
@@ -305,10 +380,10 @@ impl<O: ForestObligation> ObligationForest<O> {
             .insert(node.obligation.as_predicate().clone());
     }
 
-    /// Perform a pass through the obligation list. This must
+    /// Performs a pass through the obligation list. This must
     /// be called in a loop until `outcome.stalled` is false.
     ///
-    /// This CANNOT be unrolled (presently, at least).
+    /// This _cannot_ be unrolled (presently, at least).
     pub fn process_obligations<P>(&mut self, processor: &mut P, do_completed: DoCompleted)
                                   -> Outcome<O, P::Error>
         where P: ObligationProcessor<Obligation=O>
@@ -386,7 +461,7 @@ impl<O: ForestObligation> ObligationForest<O> {
         }
     }
 
-    /// Mark all NodeState::Success nodes as NodeState::Done and
+    /// Mark all `NodeState::Success` nodes as `NodeState::Done` and
     /// report all cycles between them. This should be called
     /// after `mark_as_waiting` marks all nodes with pending
     /// subobligations as NodeState::Waiting.
@@ -491,7 +566,7 @@ impl<O: ForestObligation> ObligationForest<O> {
         }
     }
 
-    /// Marks all nodes that depend on a pending node as NodeState::Waiting.
+    /// Marks all nodes that depend on a pending node as `NodeState::Waiting`.
     fn mark_as_waiting(&self) {
         for node in &self.nodes {
             if node.state.get() == NodeState::Waiting {
@@ -658,7 +733,7 @@ impl<O> Node<O> {
 
 // I need a Clone closure
 #[derive(Clone)]
-struct GetObligation<'a, O: 'a>(&'a [Node<O>]);
+struct GetObligation<'a, O>(&'a [Node<O>]);
 
 impl<'a, 'b, O> FnOnce<(&'b usize,)> for GetObligation<'a, O> {
     type Output = &'a O;
diff --git a/src/librustc_data_structures/owning_ref/mod.rs b/src/librustc_data_structures/owning_ref/mod.rs
index 0b126e5c572ed..236559dcd7c10 100644
--- a/src/librustc_data_structures/owning_ref/mod.rs
+++ b/src/librustc_data_structures/owning_ref/mod.rs
@@ -286,7 +286,7 @@ impl<T> Erased for T {}
 pub unsafe trait IntoErased<'a> {
     /// Owner with the dereference type substituted to `Erased`.
     type Erased;
-    /// Perform the type erasure.
+    /// Performs the type erasure.
     fn into_erased(self) -> Self::Erased;
 }
 
@@ -296,7 +296,7 @@ pub unsafe trait IntoErased<'a> {
 pub unsafe trait IntoErasedSend<'a> {
     /// Owner with the dereference type substituted to `Erased + Send`.
     type Erased: Send;
-    /// Perform the type erasure.
+    /// Performs the type erasure.
     fn into_erased_send(self) -> Self::Erased;
 }
 
@@ -306,7 +306,7 @@ pub unsafe trait IntoErasedSend<'a> {
 pub unsafe trait IntoErasedSendSync<'a> {
     /// Owner with the dereference type substituted to `Erased + Send + Sync`.
     type Erased: Send + Sync;
-    /// Perform the type erasure.
+    /// Performs the type erasure.
     fn into_erased_send_sync(self) -> Self::Erased;
 }
 
@@ -844,7 +844,7 @@ pub trait ToHandleMut {
 impl<O, H> OwningHandle<O, H>
     where O: StableAddress, O::Target: ToHandle<Handle = H>, H: Deref,
 {
-    /// Create a new `OwningHandle` for a type that implements `ToHandle`. For types
+    /// Creates a new `OwningHandle` for a type that implements `ToHandle`. For types
     /// that don't implement `ToHandle`, callers may invoke `new_with_fn`, which accepts
     /// a callback to perform the conversion.
     pub fn new(o: O) -> Self {
@@ -855,7 +855,7 @@ impl<O, H> OwningHandle<O, H>
 impl<O, H> OwningHandle<O, H>
     where O: StableAddress, O::Target: ToHandleMut<HandleMut = H>, H: DerefMut,
 {
-    /// Create a new mutable `OwningHandle` for a type that implements `ToHandleMut`.
+    /// Creates a new mutable `OwningHandle` for a type that implements `ToHandleMut`.
     pub fn new_mut(o: O) -> Self {
         OwningHandle::new_with_fn(o, |x| unsafe { O::Target::to_handle_mut(x) })
     }
@@ -864,7 +864,7 @@ impl<O, H> OwningHandle<O, H>
 impl<O, H> OwningHandle<O, H>
     where O: StableAddress, H: Deref,
 {
-    /// Create a new OwningHandle. The provided callback will be invoked with
+    /// Creates a new OwningHandle. The provided callback will be invoked with
     /// a pointer to the object owned by `o`, and the returned value is stored
     /// as the object to which this `OwningHandle` will forward `Deref` and
     /// `DerefMut`.
@@ -882,7 +882,7 @@ impl<O, H> OwningHandle<O, H>
         }
     }
 
-    /// Create a new OwningHandle. The provided callback will be invoked with
+    /// Creates a new OwningHandle. The provided callback will be invoked with
     /// a pointer to the object owned by `o`, and the returned value is stored
     /// as the object to which this `OwningHandle` will forward `Deref` and
     /// `DerefMut`.
@@ -1002,7 +1002,7 @@ impl<O, T: ?Sized> Debug for OwningRef<O, T>
     where O: Debug,
           T: Debug,
 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f,
                "OwningRef {{ owner: {:?}, reference: {:?} }}",
                self.owner(),
@@ -1014,7 +1014,7 @@ impl<O, T: ?Sized> Debug for OwningRefMut<O, T>
     where O: Debug,
           T: Debug,
 {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f,
                "OwningRefMut {{ owner: {:?}, reference: {:?} }}",
                self.owner(),
@@ -1047,7 +1047,7 @@ unsafe impl<O, T: ?Sized> Sync for OwningRefMut<O, T>
     where O: Sync, for<'a> (&'a mut T): Sync {}
 
 impl Debug for dyn Erased {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "<Erased>",)
     }
 }
diff --git a/src/librustc_data_structures/ptr_key.rs b/src/librustc_data_structures/ptr_key.rs
index 322dcbe8f08fb..bf3ae2d7af58f 100644
--- a/src/librustc_data_structures/ptr_key.rs
+++ b/src/librustc_data_structures/ptr_key.rs
@@ -4,7 +4,7 @@ use std::ops::Deref;
 /// A wrapper around reference that compares and hashes like a pointer.
 /// Can be used as a key in sets/maps indexed by pointers to avoid `unsafe`.
 #[derive(Debug)]
-pub struct PtrKey<'a, T: 'a>(pub &'a T);
+pub struct PtrKey<'a, T>(pub &'a T);
 
 impl<'a, T> Clone for PtrKey<'a, T> {
     fn clone(&self) -> Self { *self }
diff --git a/src/librustc_data_structures/sip128.rs b/src/librustc_data_structures/sip128.rs
index 9ec9a39840032..06f157f972932 100644
--- a/src/librustc_data_structures/sip128.rs
+++ b/src/librustc_data_structures/sip128.rs
@@ -44,7 +44,7 @@ macro_rules! compress {
     });
 }
 
-/// Load an integer of the desired type from a byte stream, in LE order. Uses
+/// Loads an integer of the desired type from a byte stream, in LE order. Uses
 /// `copy_nonoverlapping` to let the compiler generate the most efficient way
 /// to load it from a possibly unaligned address.
 ///
@@ -61,7 +61,7 @@ macro_rules! load_int_le {
     });
 }
 
-/// Load an u64 using up to 7 bytes of a byte slice.
+/// Loads an u64 using up to 7 bytes of a byte slice.
 ///
 /// Unsafe because: unchecked indexing at start..start+len
 #[inline]
diff --git a/src/librustc_data_structures/snapshot_map/mod.rs b/src/librustc_data_structures/snapshot_map/mod.rs
index d408727aea504..91d6e29237002 100644
--- a/src/librustc_data_structures/snapshot_map/mod.rs
+++ b/src/librustc_data_structures/snapshot_map/mod.rs
@@ -1,4 +1,4 @@
-use fx::FxHashMap;
+use crate::fx::FxHashMap;
 use std::hash::Hash;
 use std::ops;
 use std::mem;
diff --git a/src/librustc_data_structures/sorted_map.rs b/src/librustc_data_structures/sorted_map.rs
index 64bbb8d7c08d1..1f674c1c664e4 100644
--- a/src/librustc_data_structures/sorted_map.rs
+++ b/src/librustc_data_structures/sorted_map.rs
@@ -111,7 +111,7 @@ impl<K: Ord, V> SortedMap<K, V> {
 
     /// Iterate over elements, sorted by key
     #[inline]
-    pub fn iter(&self) -> ::std::slice::Iter<(K, V)> {
+    pub fn iter(&self) -> ::std::slice::Iter<'_, (K, V)> {
         self.data.iter()
     }
 
diff --git a/src/librustc_data_structures/stable_hasher.rs b/src/librustc_data_structures/stable_hasher.rs
index 4583f12ec8cbc..19343a9250df3 100644
--- a/src/librustc_data_structures/stable_hasher.rs
+++ b/src/librustc_data_structures/stable_hasher.rs
@@ -1,7 +1,9 @@
 use std::hash::{Hash, Hasher, BuildHasher};
 use std::marker::PhantomData;
 use std::mem;
-use sip128::SipHasher128;
+use crate::sip128::SipHasher128;
+use crate::indexed_vec;
+use crate::bit_set;
 
 /// When hashing something that ends up affecting properties like symbol names,
 /// we want these symbol names to be calculated independently of other factors
@@ -17,7 +19,7 @@ pub struct StableHasher<W> {
 }
 
 impl<W: StableHasherResult> ::std::fmt::Debug for StableHasher<W> {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         write!(f, "{:?}", self.state)
     }
 }
@@ -433,7 +435,7 @@ impl<T, CTX> HashStable<CTX> for ::std::mem::Discriminant<T> {
     }
 }
 
-impl<I: ::indexed_vec::Idx, T, CTX> HashStable<CTX> for ::indexed_vec::IndexVec<I, T>
+impl<I: indexed_vec::Idx, T, CTX> HashStable<CTX> for indexed_vec::IndexVec<I, T>
     where T: HashStable<CTX>,
 {
     fn hash_stable<W: StableHasherResult>(&self,
@@ -447,7 +449,7 @@ impl<I: ::indexed_vec::Idx, T, CTX> HashStable<CTX> for ::indexed_vec::IndexVec<
 }
 
 
-impl<I: ::indexed_vec::Idx, CTX> HashStable<CTX> for ::bit_set::BitSet<I>
+impl<I: indexed_vec::Idx, CTX> HashStable<CTX> for bit_set::BitSet<I>
 {
     fn hash_stable<W: StableHasherResult>(&self,
                                           ctx: &mut CTX,
diff --git a/src/librustc_data_structures/svh.rs b/src/librustc_data_structures/svh.rs
index 749479534979c..df4f61768375e 100644
--- a/src/librustc_data_structures/svh.rs
+++ b/src/librustc_data_structures/svh.rs
@@ -9,7 +9,7 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 use serialize::{Encodable, Decodable, Encoder, Decoder};
 
-use stable_hasher;
+use crate::stable_hasher;
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct Svh {
@@ -17,7 +17,7 @@ pub struct Svh {
 }
 
 impl Svh {
-    /// Create a new `Svh` given the hash. If you actually want to
+    /// Creates a new `Svh` given the hash. If you actually want to
     /// compute the SVH from some HIR, you want the `calculate_svh`
     /// function found in `librustc_incremental`.
     pub fn new(hash: u64) -> Svh {
@@ -40,7 +40,7 @@ impl Hash for Svh {
 }
 
 impl fmt::Display for Svh {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.pad(&self.to_string())
     }
 }
diff --git a/src/librustc_data_structures/sync.rs b/src/librustc_data_structures/sync.rs
index f9f94f0be7b9a..ba1f6eb56fe88 100644
--- a/src/librustc_data_structures/sync.rs
+++ b/src/librustc_data_structures/sync.rs
@@ -1,27 +1,27 @@
-//! This module defines types which are thread safe if cfg!(parallel_queries) is true.
+//! This module defines types which are thread safe if cfg!(parallel_compiler) is true.
 //!
 //! `Lrc` is an alias of either Rc or Arc.
 //!
 //! `Lock` is a mutex.
-//! It internally uses `parking_lot::Mutex` if cfg!(parallel_queries) is true,
+//! It internally uses `parking_lot::Mutex` if cfg!(parallel_compiler) is true,
 //! `RefCell` otherwise.
 //!
 //! `RwLock` is a read-write lock.
-//! It internally uses `parking_lot::RwLock` if cfg!(parallel_queries) is true,
+//! It internally uses `parking_lot::RwLock` if cfg!(parallel_compiler) is true,
 //! `RefCell` otherwise.
 //!
-//! `MTLock` is a mutex which disappears if cfg!(parallel_queries) is false.
+//! `MTLock` is a mutex which disappears if cfg!(parallel_compiler) is false.
 //!
-//! `MTRef` is a immutable reference if cfg!(parallel_queries), and an mutable reference otherwise.
+//! `MTRef` is a immutable reference if cfg!(parallel_compiler), and an mutable reference otherwise.
 //!
 //! `rustc_erase_owner!` erases a OwningRef owner into Erased or Erased + Send + Sync
-//! depending on the value of cfg!(parallel_queries).
+//! depending on the value of cfg!(parallel_compiler).
 
 use std::collections::HashMap;
 use std::hash::{Hash, BuildHasher};
 use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
-use owning_ref::{Erased, OwningRef};
+use crate::owning_ref::{Erased, OwningRef};
 
 pub fn serial_join<A, B, RA, RB>(oper_a: A, oper_b: B) -> (RA, RB)
     where A: FnOnce() -> RA,
@@ -50,7 +50,7 @@ pub use std::sync::atomic::Ordering::SeqCst;
 pub use std::sync::atomic::Ordering;
 
 cfg_if! {
-    if #[cfg(not(parallel_queries))] {
+    if #[cfg(not(parallel_compiler))] {
         pub auto trait Send {}
         pub auto trait Sync {}
 
@@ -70,6 +70,7 @@ cfg_if! {
         pub struct Atomic<T: Copy>(Cell<T>);
 
         impl<T: Copy> Atomic<T> {
+            #[inline]
             pub fn new(v: T) -> Self {
                 Atomic(Cell::new(v))
             }
@@ -80,10 +81,12 @@ cfg_if! {
                 self.0.into_inner()
             }
 
+            #[inline]
             pub fn load(&self, _: Ordering) -> T {
                 self.0.get()
             }
 
+            #[inline]
             pub fn store(&self, val: T, _: Ordering) {
                 self.0.set(val)
             }
@@ -118,11 +121,19 @@ cfg_if! {
 
         pub type AtomicUsize = Atomic<usize>;
         pub type AtomicBool = Atomic<bool>;
+        pub type AtomicU32 = Atomic<u32>;
         pub type AtomicU64 = Atomic<u64>;
 
         pub use self::serial_join as join;
         pub use self::serial_scope as scope;
 
+        #[macro_export]
+        macro_rules! parallel {
+            ($($blocks:tt),*) => {
+                $($blocks)*;
+            }
+        }
+
         pub use std::iter::Iterator as ParallelIterator;
 
         pub fn par_iter<T: IntoIterator>(t: T) -> T::IntoIter {
@@ -223,7 +234,7 @@ cfg_if! {
         pub use parking_lot::MutexGuard as LockGuard;
         pub use parking_lot::MappedMutexGuard as MappedLockGuard;
 
-        pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU64};
+        pub use std::sync::atomic::{AtomicBool, AtomicUsize, AtomicU32, AtomicU64};
 
         pub use std::sync::Arc as Lrc;
         pub use std::sync::Weak as Weak;
@@ -250,12 +261,12 @@ cfg_if! {
             }
 
             #[inline(always)]
-            pub fn lock(&self) -> LockGuard<T> {
+            pub fn lock(&self) -> LockGuard<'_, T> {
                 self.0.lock()
             }
 
             #[inline(always)]
-            pub fn lock_mut(&self) -> LockGuard<T> {
+            pub fn lock_mut(&self) -> LockGuard<'_, T> {
                 self.lock()
             }
         }
@@ -267,6 +278,26 @@ cfg_if! {
         use std::thread;
         pub use rayon::{join, scope};
 
+        #[macro_export]
+        macro_rules! parallel {
+            (impl [$($c:tt,)*] [$block:tt $(, $rest:tt)*]) => {
+                parallel!(impl [$block, $($c,)*] [$($rest),*])
+            };
+            (impl [$($blocks:tt,)*] []) => {
+                ::rustc_data_structures::sync::scope(|s| {
+                    $(
+                        s.spawn(|_| $blocks);
+                    )*
+                })
+            };
+            ($($blocks:tt),*) => {
+                // Reverse the order of the blocks since Rayon executes them in reverse order
+                // when using a single thread. This ensures the execution order matches that
+                // of a single threaded rustc
+                parallel!(impl [] [$($blocks),*]);
+            };
+        }
+
         pub use rayon_core::WorkerLocal;
 
         pub use rayon::iter::ParallelIterator;
@@ -457,21 +488,21 @@ impl<T> Lock<T> {
         self.0.get_mut()
     }
 
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline(always)]
-    pub fn try_lock(&self) -> Option<LockGuard<T>> {
+    pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
         self.0.try_lock()
     }
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline(always)]
-    pub fn try_lock(&self) -> Option<LockGuard<T>> {
+    pub fn try_lock(&self) -> Option<LockGuard<'_, T>> {
         self.0.try_borrow_mut().ok()
     }
 
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline(always)]
-    pub fn lock(&self) -> LockGuard<T> {
+    pub fn lock(&self) -> LockGuard<'_, T> {
         if ERROR_CHECKING {
             self.0.try_lock().expect("lock was already held")
         } else {
@@ -479,9 +510,9 @@ impl<T> Lock<T> {
         }
     }
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline(always)]
-    pub fn lock(&self) -> LockGuard<T> {
+    pub fn lock(&self) -> LockGuard<'_, T> {
         self.0.borrow_mut()
     }
 
@@ -491,12 +522,12 @@ impl<T> Lock<T> {
     }
 
     #[inline(always)]
-    pub fn borrow(&self) -> LockGuard<T> {
+    pub fn borrow(&self) -> LockGuard<'_, T> {
         self.lock()
     }
 
     #[inline(always)]
-    pub fn borrow_mut(&self) -> LockGuard<T> {
+    pub fn borrow_mut(&self) -> LockGuard<'_, T> {
         self.lock()
     }
 }
@@ -535,15 +566,15 @@ impl<T> RwLock<T> {
         self.0.get_mut()
     }
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline(always)]
-    pub fn read(&self) -> ReadGuard<T> {
+    pub fn read(&self) -> ReadGuard<'_, T> {
         self.0.borrow()
     }
 
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline(always)]
-    pub fn read(&self) -> ReadGuard<T> {
+    pub fn read(&self) -> ReadGuard<'_, T> {
         if ERROR_CHECKING {
             self.0.try_read().expect("lock was already held")
         } else {
@@ -556,27 +587,27 @@ impl<T> RwLock<T> {
         f(&*self.read())
     }
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline(always)]
-    pub fn try_write(&self) -> Result<WriteGuard<T>, ()> {
+    pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
         self.0.try_borrow_mut().map_err(|_| ())
     }
 
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline(always)]
-    pub fn try_write(&self) -> Result<WriteGuard<T>, ()> {
+    pub fn try_write(&self) -> Result<WriteGuard<'_, T>, ()> {
         self.0.try_write().ok_or(())
     }
 
-    #[cfg(not(parallel_queries))]
+    #[cfg(not(parallel_compiler))]
     #[inline(always)]
-    pub fn write(&self) -> WriteGuard<T> {
+    pub fn write(&self) -> WriteGuard<'_, T> {
         self.0.borrow_mut()
     }
 
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     #[inline(always)]
-    pub fn write(&self) -> WriteGuard<T> {
+    pub fn write(&self) -> WriteGuard<'_, T> {
         if ERROR_CHECKING {
             self.0.try_write().expect("lock was already held")
         } else {
@@ -590,12 +621,12 @@ impl<T> RwLock<T> {
     }
 
     #[inline(always)]
-    pub fn borrow(&self) -> ReadGuard<T> {
+    pub fn borrow(&self) -> ReadGuard<'_, T> {
         self.read()
     }
 
     #[inline(always)]
-    pub fn borrow_mut(&self) -> WriteGuard<T> {
+    pub fn borrow_mut(&self) -> WriteGuard<'_, T> {
         self.write()
     }
 }
@@ -612,27 +643,27 @@ impl<T: Clone> Clone for RwLock<T> {
 /// It will panic if it is used on multiple threads.
 #[derive(Copy, Clone, Hash, Debug, Eq, PartialEq)]
 pub struct OneThread<T> {
-    #[cfg(parallel_queries)]
+    #[cfg(parallel_compiler)]
     thread: thread::ThreadId,
     inner: T,
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 unsafe impl<T> std::marker::Sync for OneThread<T> {}
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 unsafe impl<T> std::marker::Send for OneThread<T> {}
 
 impl<T> OneThread<T> {
     #[inline(always)]
     fn check(&self) {
-        #[cfg(parallel_queries)]
+        #[cfg(parallel_compiler)]
         assert_eq!(thread::current().id(), self.thread);
     }
 
     #[inline(always)]
     pub fn new(inner: T) -> Self {
         OneThread {
-            #[cfg(parallel_queries)]
+            #[cfg(parallel_compiler)]
             thread: thread::current().id(),
             inner,
         }
diff --git a/src/librustc_data_structures/thin_vec.rs b/src/librustc_data_structures/thin_vec.rs
index 359f9b7842da3..ed57c528f51e0 100644
--- a/src/librustc_data_structures/thin_vec.rs
+++ b/src/librustc_data_structures/thin_vec.rs
@@ -39,6 +39,15 @@ impl<T> ::std::ops::Deref for ThinVec<T> {
     }
 }
 
+impl<T> ::std::ops::DerefMut for ThinVec<T> {
+    fn deref_mut(&mut self) -> &mut [T] {
+        match *self {
+            ThinVec(None) => &mut [],
+            ThinVec(Some(ref mut vec)) => vec,
+        }
+    }
+}
+
 impl<T> Extend<T> for ThinVec<T> {
     fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
         match *self {
diff --git a/src/librustc_data_structures/tiny_list.rs b/src/librustc_data_structures/tiny_list.rs
index d660486d58446..3d74516d9c326 100644
--- a/src/librustc_data_structures/tiny_list.rs
+++ b/src/librustc_data_structures/tiny_list.rs
@@ -123,7 +123,7 @@ impl<T: PartialEq> Element<T> {
 mod test {
     use super::*;
     extern crate test;
-    use self::test::Bencher;
+    use test::Bencher;
 
     #[test]
     fn test_contains_and_insert() {
diff --git a/src/librustc_data_structures/transitive_relation.rs b/src/librustc_data_structures/transitive_relation.rs
index 9d675ed3096e0..0974607fabea8 100644
--- a/src/librustc_data_structures/transitive_relation.rs
+++ b/src/librustc_data_structures/transitive_relation.rs
@@ -1,8 +1,8 @@
-use bit_set::BitMatrix;
-use fx::FxHashMap;
-use sync::Lock;
+use crate::bit_set::BitMatrix;
+use crate::fx::FxHashMap;
+use crate::stable_hasher::{HashStable, StableHasher, StableHasherResult};
+use crate::sync::Lock;
 use rustc_serialize::{Encodable, Encoder, Decodable, Decoder};
-use stable_hasher::{HashStable, StableHasher, StableHasherResult};
 use std::fmt::Debug;
 use std::hash::Hash;
 use std::mem;
@@ -82,7 +82,7 @@ impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
     }
 
     /// Applies the (partial) function to each edge and returns a new
-    /// relation.  If `f` returns `None` for any end-point, returns
+    /// relation. If `f` returns `None` for any end-point, returns
     /// `None`.
     pub fn maybe_map<F, U>(&self, mut f: F) -> Option<TransitiveRelation<U>>
         where F: FnMut(&T) -> Option<U>,
@@ -111,7 +111,7 @@ impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
         }
     }
 
-    /// Check whether `a < target` (transitively)
+    /// Checks whether `a < target` (transitively)
     pub fn contains(&self, a: &T, b: &T) -> bool {
         match (self.index(a), self.index(b)) {
             (Some(a), Some(b)) => self.with_closure(|closure| closure.contains(a.0, b.0)),
@@ -122,7 +122,7 @@ impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
     /// Thinking of `x R y` as an edge `x -> y` in a graph, this
     /// returns all things reachable from `a`.
     ///
-    /// Really this probably ought to be `impl Iterator<Item=&T>`, but
+    /// Really this probably ought to be `impl Iterator<Item = &T>`, but
     /// I'm too lazy to make that work, and -- given the caching
     /// strategy -- it'd be a touch tricky anyhow.
     pub fn reachable_from(&self, a: &T) -> Vec<&T> {
@@ -152,20 +152,20 @@ impl<T: Clone + Debug + Eq + Hash> TransitiveRelation<T> {
     /// the query is `postdom_upper_bound(a, b)`:
     ///
     /// ```text
-    /// // returns Some(x), which is also LUB
+    /// // Returns Some(x), which is also LUB.
     /// a -> a1 -> x
     ///            ^
     ///            |
     /// b -> b1 ---+
     ///
-    /// // returns Some(x), which is not LUB (there is none)
-    /// // diagonal edges run left-to-right
+    /// // Returns `Some(x)`, which is not LUB (there is none)
+    /// // diagonal edges run left-to-right.
     /// a -> a1 -> x
     ///   \/       ^
     ///   /\       |
     /// b -> b1 ---+
     ///
-    /// // returns None
+    /// // Returns `None`.
     /// a -> a1
     /// b -> b1
     /// ```
diff --git a/src/librustc_data_structures/vec_linked_list.rs b/src/librustc_data_structures/vec_linked_list.rs
index 3b6984dd07599..c00c707a43542 100644
--- a/src/librustc_data_structures/vec_linked_list.rs
+++ b/src/librustc_data_structures/vec_linked_list.rs
@@ -1,4 +1,4 @@
-use indexed_vec::{Idx, IndexVec};
+use crate::indexed_vec::{Idx, IndexVec};
 
 pub fn iter<Ls>(
     first: Option<Ls::LinkIndex>,
diff --git a/src/librustc_data_structures/work_queue.rs b/src/librustc_data_structures/work_queue.rs
index 0a928de7961b5..193025aafad20 100644
--- a/src/librustc_data_structures/work_queue.rs
+++ b/src/librustc_data_structures/work_queue.rs
@@ -1,5 +1,5 @@
-use bit_set::BitSet;
-use indexed_vec::Idx;
+use crate::bit_set::BitSet;
+use crate::indexed_vec::Idx;
 use std::collections::VecDeque;
 
 /// A work queue is a handy data structure for tracking work left to
@@ -14,7 +14,7 @@ pub struct WorkQueue<T: Idx> {
 }
 
 impl<T: Idx> WorkQueue<T> {
-    /// Create a new work queue with all the elements from (0..len).
+    /// Creates a new work queue with all the elements from (0..len).
     #[inline]
     pub fn with_all(len: usize) -> Self {
         WorkQueue {
@@ -23,7 +23,7 @@ impl<T: Idx> WorkQueue<T> {
         }
     }
 
-    /// Create a new work queue that starts empty, where elements range from (0..len).
+    /// Creates a new work queue that starts empty, where elements range from (0..len).
     #[inline]
     pub fn with_none(len: usize) -> Self {
         WorkQueue {
@@ -54,7 +54,7 @@ impl<T: Idx> WorkQueue<T> {
         }
     }
 
-    /// True if nothing is enqueued.
+    /// Returns `true` if nothing is enqueued.
     #[inline]
     pub fn is_empty(&self) -> bool {
         self.deque.is_empty()
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index 1ecb8ef112c9e..b998b77a76b9c 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -22,7 +22,7 @@ use rustc_incremental;
 use rustc_metadata::creader::CrateLoader;
 use rustc_metadata::cstore::{self, CStore};
 use rustc_mir as mir;
-use rustc_passes::{self, ast_validation, hir_stats, loops, rvalue_promotion};
+use rustc_passes::{self, ast_validation, hir_stats, loops, rvalue_promotion, layout_test};
 use rustc_plugin as plugin;
 use rustc_plugin::registry::Registry;
 use rustc_privacy;
@@ -32,7 +32,7 @@ use rustc_typeck as typeck;
 use syntax::{self, ast, attr, diagnostics, visit};
 use syntax::early_buffered_lints::BufferedEarlyLint;
 use syntax::ext::base::ExtCtxt;
-use syntax::fold::Folder;
+use syntax::mut_visit::MutVisitor;
 use syntax::parse::{self, PResult};
 use syntax::util::node_count::NodeCounter;
 use syntax::util::lev_distance::find_best_match_for_name;
@@ -56,7 +56,7 @@ use proc_macro_decls;
 use profile;
 use super::Compilation;
 
-#[cfg(not(parallel_queries))]
+#[cfg(not(parallel_compiler))]
 pub fn spawn_thread_pool<F: FnOnce(config::Options) -> R + sync::Send, R: sync::Send>(
     opts: config::Options,
     f: F
@@ -66,7 +66,7 @@ pub fn spawn_thread_pool<F: FnOnce(config::Options) -> R + sync::Send, R: sync::
     })
 }
 
-#[cfg(parallel_queries)]
+#[cfg(parallel_compiler)]
 pub fn spawn_thread_pool<F: FnOnce(config::Options) -> R + sync::Send, R: sync::Send>(
     opts: config::Options,
     f: F
@@ -78,7 +78,7 @@ pub fn spawn_thread_pool<F: FnOnce(config::Options) -> R + sync::Send, R: sync::
     let gcx_ptr = &Lock::new(0);
 
     let config = ThreadPoolBuilder::new()
-        .num_threads(Session::query_threads_from_opts(&opts))
+        .num_threads(Session::threads_from_opts(&opts))
         .deadlock_handler(|| unsafe { ty::query::handle_deadlock() })
         .stack_size(::STACK_SIZE);
 
@@ -168,7 +168,6 @@ pub fn compile_input(
         let ExpansionResult {
             expanded_crate,
             defs,
-            analysis,
             resolutions,
             mut hir_forest,
         } = {
@@ -251,7 +250,6 @@ pub fn compile_input(
                     output,
                     &cstore,
                     &hir_map,
-                    &analysis,
                     &resolutions,
                     &expanded_crate,
                     &hir_map.krate(),
@@ -277,12 +275,11 @@ pub fn compile_input(
             sess,
             cstore,
             hir_map,
-            analysis,
             resolutions,
             &mut arenas,
             &crate_name,
             &outputs,
-            |tcx, analysis, rx, result| {
+            |tcx, rx, result| {
                 {
                     // Eventually, we will want to track plugins.
                     tcx.dep_graph.with_ignore(|| {
@@ -293,13 +290,17 @@ pub fn compile_input(
                             output,
                             opt_crate,
                             tcx.hir().krate(),
-                            &analysis,
                             tcx,
                             &crate_name,
                         );
                         (control.after_analysis.callback)(&mut state);
                     });
 
+                    // Plugins like clippy and rust-semverver stop the analysis early,
+                    // but want to still return an error if errors during the analysis
+                    // happened:
+                    tcx.sess.compile_status()?;
+
                     if control.after_analysis.stop == Compilation::Stop {
                         return result.and_then(|_| Err(CompileIncomplete::Stopped));
                     }
@@ -527,7 +528,6 @@ pub struct CompileState<'a, 'tcx: 'a> {
     pub hir_crate: Option<&'a hir::Crate>,
     pub hir_map: Option<&'a hir_map::Map<'tcx>>,
     pub resolutions: Option<&'a Resolutions>,
-    pub analysis: Option<&'a ty::CrateAnalysis>,
     pub tcx: Option<TyCtxt<'a, 'tcx, 'tcx>>,
 }
 
@@ -547,7 +547,6 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
             hir_crate: None,
             hir_map: None,
             resolutions: None,
-            analysis: None,
             tcx: None,
         }
     }
@@ -595,7 +594,6 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
         out_file: &'a Option<PathBuf>,
         cstore: &'tcx CStore,
         hir_map: &'a hir_map::Map<'tcx>,
-        analysis: &'a ty::CrateAnalysis,
         resolutions: &'a Resolutions,
         krate: &'a ast::Crate,
         hir_crate: &'a hir::Crate,
@@ -606,7 +604,6 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
             crate_name: Some(crate_name),
             cstore: Some(cstore),
             hir_map: Some(hir_map),
-            analysis: Some(analysis),
             resolutions: Some(resolutions),
             expanded_crate: Some(krate),
             hir_crate: Some(hir_crate),
@@ -623,12 +620,10 @@ impl<'a, 'tcx> CompileState<'a, 'tcx> {
         out_file: &'a Option<PathBuf>,
         krate: Option<&'a ast::Crate>,
         hir_crate: &'a hir::Crate,
-        analysis: &'a ty::CrateAnalysis,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
         crate_name: &'a str,
     ) -> Self {
         CompileState {
-            analysis: Some(analysis),
             tcx: Some(tcx),
             expanded_crate: krate,
             hir_crate: Some(hir_crate),
@@ -711,7 +706,6 @@ fn count_nodes(krate: &ast::Crate) -> usize {
 pub struct ExpansionResult {
     pub expanded_crate: ast::Crate,
     pub defs: hir_map::Definitions,
-    pub analysis: ty::CrateAnalysis,
     pub resolutions: Resolutions,
     pub hir_forest: hir_map::Forest,
 }
@@ -722,7 +716,7 @@ pub struct InnerExpansionResult<'a> {
     pub hir_forest: hir_map::Forest,
 }
 
-/// Run the "early phases" of the compiler: initial `cfg` processing,
+/// Runs the "early phases" of the compiler: initial `cfg` processing,
 /// loading compiler plugins (including those from `addl_plugins`),
 /// syntax expansion, secondary `cfg` expansion, synthesis of a test
 /// harness if one is to be provided, injection of a dependency on the
@@ -772,16 +766,13 @@ where
                 freevars: resolver.freevars,
                 export_map: resolver.export_map,
                 trait_map: resolver.trait_map,
+                glob_map: resolver.glob_map,
                 maybe_unused_trait_imports: resolver.maybe_unused_trait_imports,
                 maybe_unused_extern_crates: resolver.maybe_unused_extern_crates,
                 extern_prelude: resolver.extern_prelude.iter().map(|(ident, entry)| {
                     (ident.name, entry.introduced_by_item)
                 }).collect(),
             },
-
-            analysis: ty::CrateAnalysis {
-                glob_map: resolver.glob_map
-            },
         }),
         Err(x) => Err(x),
     }
@@ -898,7 +889,7 @@ where
     sess.track_errors(|| {
         let mut ls = sess.lint_store.borrow_mut();
         for pass in early_lint_passes {
-            ls.register_early_pass(Some(sess), true, pass);
+            ls.register_early_pass(Some(sess), true, false, pass);
         }
         for pass in late_lint_passes {
             ls.register_late_pass(Some(sess), true, pass);
@@ -919,7 +910,11 @@ where
     }
 
     time(sess, "pre ast expansion lint checks", || {
-        lint::check_ast_crate(sess, &krate, true)
+        lint::check_ast_crate(
+            sess,
+            &krate,
+            true,
+            rustc_lint::BuiltinCombinedPreExpansionLintPass::new());
     });
 
     let mut resolver = Resolver::new(
@@ -930,7 +925,7 @@ where
         crate_loader,
         &resolver_arenas,
     );
-    syntax_ext::register_builtins(&mut resolver, syntax_exts, sess.features_untracked().quote);
+    syntax_ext::register_builtins(&mut resolver, syntax_exts);
 
     // Expand all macros
     sess.profiler(|p| p.start_activity(ProfileCategory::Expansion));
@@ -1010,12 +1005,12 @@ where
     });
     sess.profiler(|p| p.end_activity(ProfileCategory::Expansion));
 
-    krate = time(sess, "maybe building test harness", || {
+    time(sess, "maybe building test harness", || {
         syntax::test::modify_for_testing(
             &sess.parse_sess,
             &mut resolver,
             sess.opts.test,
-            krate,
+            &mut krate,
             sess.diagnostic(),
             &sess.features_untracked(),
         )
@@ -1024,9 +1019,13 @@ where
     // If we're actually rustdoc then there's no need to actually compile
     // anything, so switch everything to just looping
     if sess.opts.actually_rustdoc {
-        krate = ReplaceBodyWithLoop::new(sess).fold_crate(krate);
+        ReplaceBodyWithLoop::new(sess).visit_crate(&mut krate);
     }
 
+    let (has_proc_macro_decls, has_global_allocator) = time(sess, "AST validation", || {
+        ast_validation::check_crate(sess, &krate)
+    });
+
     // If we're in rustdoc we're always compiling as an rlib, but that'll trip a
     // bunch of checks in the `modify` function below. For now just skip this
     // step entirely if we're rustdoc as it's not too useful anyway.
@@ -1041,6 +1040,7 @@ where
                 &mut resolver,
                 krate,
                 is_proc_macro_crate,
+                has_proc_macro_decls,
                 is_test_crate,
                 num_crate_types,
                 sess.diagnostic(),
@@ -1048,16 +1048,18 @@ where
         });
     }
 
-    // Expand global allocators, which are treated as an in-tree proc macro
-    krate = time(sess, "creating allocators", || {
-        allocator::expand::modify(
-            &sess.parse_sess,
-            &mut resolver,
-            krate,
-            crate_name.to_string(),
-            sess.diagnostic(),
-        )
-    });
+    if has_global_allocator {
+        // Expand global allocators, which are treated as an in-tree proc macro
+        time(sess, "creating allocators", || {
+            allocator::expand::modify(
+                &sess.parse_sess,
+                &mut resolver,
+                &mut krate,
+                crate_name.to_string(),
+                sess.diagnostic(),
+            )
+        });
+    }
 
     // Done with macro expansion!
 
@@ -1075,10 +1077,6 @@ where
         println!("{}", json::as_json(&krate));
     }
 
-    time(sess, "AST validation", || {
-        ast_validation::check_crate(sess, &krate)
-    });
-
     time(sess, "name resolution", || {
         resolver.resolve_crate(&krate);
     });
@@ -1131,7 +1129,7 @@ where
     });
 
     time(sess, "early lint checks", || {
-        lint::check_ast_crate(sess, &krate, false)
+        lint::check_ast_crate(sess, &krate, false, rustc_lint::BuiltinCombinedEarlyLintPass::new())
     });
 
     // Discard hygiene data, which isn't required after lowering to HIR.
@@ -1159,10 +1157,13 @@ pub fn default_provide(providers: &mut ty::query::Providers) {
     ty::provide(providers);
     traits::provide(providers);
     stability::provide(providers);
+    middle::intrinsicck::provide(providers);
+    middle::liveness::provide(providers);
     reachable::provide(providers);
     rustc_passes::provide(providers);
     rustc_traits::provide(providers);
     middle::region::provide(providers);
+    middle::entry::provide(providers);
     cstore::provide(providers);
     lint::provide(providers);
 }
@@ -1171,7 +1172,7 @@ pub fn default_provide_extern(providers: &mut ty::query::Providers) {
     cstore::provide_extern(providers);
 }
 
-/// Run the resolution, typechecking, region checking and other
+/// Runs the resolution, type-checking, region checking and other
 /// miscellaneous analysis passes on the crate. Return various
 /// structures carrying the results of the analysis.
 pub fn phase_3_run_analysis_passes<'tcx, F, R>(
@@ -1180,7 +1181,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(
     sess: &'tcx Session,
     cstore: &'tcx CStore,
     hir_map: hir_map::Map<'tcx>,
-    analysis: ty::CrateAnalysis,
     resolutions: Resolutions,
     arenas: &'tcx mut AllArenas<'tcx>,
     name: &str,
@@ -1190,7 +1190,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(
 where
     F: for<'a> FnOnce(
         TyCtxt<'a, 'tcx, 'tcx>,
-        ty::CrateAnalysis,
         mpsc::Receiver<Box<dyn Any + Send>>,
         CompileResult,
     ) -> R,
@@ -1199,10 +1198,6 @@ where
         rustc_incremental::load_query_result_cache(sess)
     });
 
-    time(sess, "looking for entry point", || {
-        middle::entry::find_entry_point(sess, &hir_map, name)
-    });
-
     let mut local_providers = ty::query::Providers::default();
     default_provide(&mut local_providers);
     codegen_backend.provide(&mut local_providers);
@@ -1232,54 +1227,64 @@ where
             // tcx available.
             time(sess, "dep graph tcx init", || rustc_incremental::dep_graph_tcx_init(tcx));
 
-            time(sess, "looking for plugin registrar", || {
-                plugin::build::find_plugin_registrar(tcx)
-            });
-
-            time(sess, "looking for derive registrar", || {
-                proc_macro_decls::find(tcx)
-            });
-
-            time(sess, "loop checking", || loops::check_crate(tcx));
+            parallel!({
+                time(sess, "looking for entry point", || {
+                    middle::entry::find_entry_point(tcx)
+                });
 
-            time(sess, "attribute checking", || {
-                hir::check_attr::check_crate(tcx)
-            });
+                time(sess, "looking for plugin registrar", || {
+                    plugin::build::find_plugin_registrar(tcx)
+                });
 
-            time(sess, "stability checking", || {
-                stability::check_unstable_api_usage(tcx)
+                time(sess, "looking for derive registrar", || {
+                    proc_macro_decls::find(tcx)
+                });
+            }, {
+                time(sess, "loop checking", || loops::check_crate(tcx));
+            }, {
+                time(sess, "attribute checking", || {
+                    hir::check_attr::check_crate(tcx)
+                });
+            }, {
+                time(sess, "stability checking", || {
+                    stability::check_unstable_api_usage(tcx)
+                });
             });
 
             // passes are timed inside typeck
             match typeck::check_crate(tcx) {
                 Ok(x) => x,
                 Err(x) => {
-                    f(tcx, analysis, rx, Err(x));
+                    f(tcx, rx, Err(x));
                     return Err(x);
                 }
             }
 
-            time(sess, "rvalue promotion", || {
-                rvalue_promotion::check_crate(tcx)
-            });
-
-            time(sess, "privacy checking", || {
-                rustc_privacy::check_crate(tcx)
-            });
-
-            time(sess, "intrinsic checking", || {
-                middle::intrinsicck::check_crate(tcx)
+            time(sess, "misc checking", || {
+                parallel!({
+                    time(sess, "rvalue promotion", || {
+                        rvalue_promotion::check_crate(tcx)
+                    });
+                }, {
+                    time(sess, "intrinsic checking", || {
+                        middle::intrinsicck::check_crate(tcx)
+                    });
+                }, {
+                    time(sess, "match checking", || mir::matchck_crate(tcx));
+                }, {
+                    // this must run before MIR dump, because
+                    // "not all control paths return a value" is reported here.
+                    //
+                    // maybe move the check to a MIR pass?
+                    time(sess, "liveness checking", || {
+                        middle::liveness::check_crate(tcx)
+                    });
+                });
             });
 
-            time(sess, "match checking", || mir::matchck_crate(tcx));
-
-            // this must run before MIR dump, because
-            // "not all control paths return a value" is reported here.
-            //
-            // maybe move the check to a MIR pass?
-            time(sess, "liveness checking", || {
-                middle::liveness::check_crate(tcx)
-            });
+            // Abort so we don't try to construct MIR with liveness errors.
+            // We also won't want to continue with errors from rvalue promotion
+            tcx.sess.abort_if_errors();
 
             time(sess, "borrow checking", || {
                 if tcx.use_ast_borrowck() {
@@ -1289,7 +1294,7 @@ where
 
             time(sess,
                  "MIR borrow checking",
-                 || tcx.par_body_owners(|def_id| { tcx.mir_borrowck(def_id); }));
+                 || tcx.par_body_owners(|def_id| { tcx.ensure().mir_borrowck(def_id); }));
 
             time(sess, "dumping chalk-like clauses", || {
                 rustc_traits::lowering::dump_program_clauses(tcx);
@@ -1300,30 +1305,41 @@ where
                     mir::transform::check_unsafety::check_unsafety(tcx, def_id)
                 }
             });
-            // Avoid overwhelming user with errors if type checking failed.
+
+            time(sess, "layout testing", || layout_test::test_layout(tcx));
+
+            // Avoid overwhelming user with errors if borrow checking failed.
             // I'm not sure how helpful this is, to be honest, but it avoids
             // a
             // lot of annoying errors in the compile-fail tests (basically,
             // lint warnings and so on -- kindck used to do this abort, but
             // kindck is gone now). -nmatsakis
             if sess.err_count() > 0 {
-                return Ok(f(tcx, analysis, rx, sess.compile_status()));
+                return Ok(f(tcx, rx, sess.compile_status()));
             }
 
-            time(sess, "death checking", || middle::dead::check_crate(tcx));
-
-            time(sess, "unused lib feature checking", || {
-                stability::check_unused_or_stable_features(tcx)
+            time(sess, "misc checking", || {
+                parallel!({
+                    time(sess, "privacy checking", || {
+                        rustc_privacy::check_crate(tcx)
+                    });
+                }, {
+                    time(sess, "death checking", || middle::dead::check_crate(tcx));
+                },  {
+                    time(sess, "unused lib feature checking", || {
+                        stability::check_unused_or_stable_features(tcx)
+                    });
+                }, {
+                    time(sess, "lint checking", || lint::check_crate(tcx));
+                });
             });
 
-            time(sess, "lint checking", || lint::check_crate(tcx));
-
-            return Ok(f(tcx, analysis, rx, tcx.sess.compile_status()));
+            return Ok(f(tcx, rx, tcx.sess.compile_status()));
         },
     )
 }
 
-/// Run the codegen backend, after which the AST and analysis can
+/// Runs the codegen backend, after which the AST and analysis can
 /// be discarded.
 pub fn phase_4_codegen<'a, 'tcx>(
     codegen_backend: &dyn CodegenBackend,
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 010ac28cdc944..e022d3a3818a5 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -4,16 +4,12 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_syntax)]
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]
-#![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(set_stdio)]
 #![feature(no_debug)]
 #![feature(integer_atomics)]
@@ -31,6 +27,7 @@ extern crate rustc;
 extern crate rustc_allocator;
 extern crate rustc_target;
 extern crate rustc_borrowck;
+#[macro_use]
 extern crate rustc_data_structures;
 extern crate rustc_errors as errors;
 extern crate rustc_passes;
@@ -92,7 +89,7 @@ use std::panic;
 use std::path::{PathBuf, Path};
 use std::process::{self, Command, Stdio};
 use std::str;
-use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Once, ONCE_INIT};
 use std::thread;
 
@@ -116,7 +113,7 @@ pub mod target_features {
     use rustc::session::Session;
     use rustc_codegen_utils::codegen_backend::CodegenBackend;
 
-    /// Add `target_feature = "..."` cfgs for a variety of platform
+    /// Adds `target_feature = "..."` cfgs for a variety of platform
     /// specific features (SSE, NEON etc.).
     ///
     /// This is performed by checking whether a whitelisted set of
@@ -255,7 +252,7 @@ fn get_codegen_sysroot(backend_name: &str) -> fn() -> Box<dyn CodegenBackend> {
     // general this assertion never trips due to the once guard in `get_codegen_backend`,
     // but there's a few manual calls to this function in this file we protect
     // against.
-    static LOADED: AtomicBool = ATOMIC_BOOL_INIT;
+    static LOADED: AtomicBool = AtomicBool::new(false);
     assert!(!LOADED.fetch_or(true, Ordering::SeqCst),
             "cannot load the default codegen backend twice");
 
@@ -840,7 +837,15 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
                 early_error(sopts.error_format, "no input filename given");
             }
             1 => panic!("make_input should have provided valid inputs"),
-            _ => early_error(sopts.error_format, "multiple input filenames provided"),
+            _ =>
+                early_error(
+                    sopts.error_format,
+                    &format!(
+                        "multiple input filenames provided (first two filenames are `{}` and `{}`)",
+                        matches.free[0],
+                        matches.free[1],
+                    ),
+                )
         }
     }
 
@@ -871,15 +876,14 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
                 control.after_hir_lowering.stop = Compilation::Stop;
 
                 control.after_parse.callback = box move |state| {
-                    state.krate = Some(pretty::fold_crate(state.session,
-                                                          state.krate.take().unwrap(),
-                                                          ppm));
+                    let mut krate = state.krate.take().unwrap();
+                    pretty::visit_crate(state.session, &mut krate, ppm);
+                    state.krate = Some(krate);
                 };
                 control.after_hir_lowering.callback = box move |state| {
                     pretty::print_after_hir_lowering(state.session,
                                                      state.cstore.unwrap(),
                                                      state.hir_map.unwrap(),
-                                                     state.analysis.unwrap(),
                                                      state.resolutions.unwrap(),
                                                      state.input,
                                                      &state.expanded_crate.take().unwrap(),
@@ -893,7 +897,8 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
                 control.after_parse.stop = Compilation::Stop;
 
                 control.after_parse.callback = box move |state| {
-                    let krate = pretty::fold_crate(state.session, state.krate.take().unwrap(), ppm);
+                    let mut krate = state.krate.take().unwrap();
+                    pretty::visit_crate(state.session, &mut krate, ppm);
                     pretty::print_after_parsing(state.session,
                                                 state.input,
                                                 &krate,
@@ -940,7 +945,6 @@ pub fn enable_save_analysis(control: &mut CompileController) {
         time(state.session, "save analysis", || {
             save::process_crate(state.tcx.unwrap(),
                                 state.expanded_crate.unwrap(),
-                                state.analysis.unwrap(),
                                 state.crate_name.unwrap(),
                                 state.input,
                                 None,
@@ -1319,7 +1323,7 @@ fn print_flag_list<T>(cmdline_opt: &str,
 
 /// Process command line options. Emits messages as appropriate. If compilation
 /// should continue, returns a getopts::Matches object parsed from args,
-/// otherwise returns None.
+/// otherwise returns `None`.
 ///
 /// The compiler's handling of options is a little complicated as it ties into
 /// our stability story, and it's even *more* complicated by historical
@@ -1483,7 +1487,7 @@ pub fn in_rustc_thread<F, R>(f: F) -> Result<R, Box<dyn Any + Send>>
     in_named_rustc_thread("rustc".to_string(), f)
 }
 
-/// Get a list of extra command-line flags provided by the user, as strings.
+/// Gets a list of extra command-line flags provided by the user, as strings.
 ///
 /// This function is used during ICEs to show more information useful for
 /// debugging, since some ICEs only happens with non-default compiler flags
@@ -1548,7 +1552,7 @@ impl Display for CompilationFailure {
     }
 }
 
-/// Run a procedure which will detect panics in the compiler and print nicer
+/// Runs a procedure which will detect panics in the compiler and print nicer
 /// error messages rather than just failing the test.
 ///
 /// The diagnostic emitter yielded to the procedure should be used for reporting
diff --git a/src/librustc_driver/pretty.rs b/src/librustc_driver/pretty.rs
index a9ec99358c1b2..4caf2ec676f07 100644
--- a/src/librustc_driver/pretty.rs
+++ b/src/librustc_driver/pretty.rs
@@ -16,7 +16,7 @@ use rustc_metadata::cstore::CStore;
 use rustc_mir::util::{write_mir_pretty, write_mir_graphviz};
 
 use syntax::ast::{self, BlockCheckMode};
-use syntax::fold::{self, Folder};
+use syntax::mut_visit::{*, MutVisitor, visit_clobber};
 use syntax::print::{pprust};
 use syntax::print::pprust::PrintState;
 use syntax::ptr::P;
@@ -28,6 +28,7 @@ use smallvec::SmallVec;
 use std::cell::Cell;
 use std::fs::File;
 use std::io::{self, Write};
+use std::ops::DerefMut;
 use std::option;
 use std::path::Path;
 use std::str::FromStr;
@@ -123,7 +124,8 @@ pub fn parse_pretty(sess: &Session,
                 sess.fatal(&format!("argument to `unpretty` must be one of `normal`, \
                                      `expanded`, `flowgraph[,unlabelled]=<nodeid>`, \
                                      `identified`, `expanded,identified`, `everybody_loops`, \
-                                     `hir`, `hir,identified`, `hir,typed`, or `mir`; got {}",
+                                     `hir`, `hir,identified`, `hir,typed`, `hir-tree`, \
+                                     `mir` or `mir-cfg`; got {}",
                                     name));
             } else {
                 sess.fatal(&format!("argument to `pretty` must be one of `normal`, `expanded`, \
@@ -190,7 +192,6 @@ impl PpSourceMode {
         sess: &'tcx Session,
         cstore: &'tcx CStore,
         hir_map: &hir_map::Map<'tcx>,
-        analysis: &ty::CrateAnalysis,
         resolutions: &Resolutions,
         output_filenames: &OutputFilenames,
         id: &str,
@@ -223,12 +224,11 @@ impl PpSourceMode {
                                                                  sess,
                                                                  cstore,
                                                                  hir_map.clone(),
-                                                                 analysis.clone(),
                                                                  resolutions.clone(),
                                                                  &mut arenas,
                                                                  id,
                                                                  output_filenames,
-                                                                 |tcx, _, _, _| {
+                                                                 |tcx, _, _| {
                     let empty_tables = ty::TypeckTables::empty(None);
                     let annotation = TypedAnnotation {
                         tcx,
@@ -704,42 +704,42 @@ impl<'a> ReplaceBodyWithLoop<'a> {
     }
 }
 
-impl<'a> fold::Folder for ReplaceBodyWithLoop<'a> {
-    fn fold_item_kind(&mut self, i: ast::ItemKind) -> ast::ItemKind {
+impl<'a> MutVisitor for ReplaceBodyWithLoop<'a> {
+    fn visit_item_kind(&mut self, i: &mut ast::ItemKind) {
         let is_const = match i {
             ast::ItemKind::Static(..) | ast::ItemKind::Const(..) => true,
             ast::ItemKind::Fn(ref decl, ref header, _, _) =>
                 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
             _ => false,
         };
-        self.run(is_const, |s| fold::noop_fold_item_kind(i, s))
+        self.run(is_const, |s| noop_visit_item_kind(i, s))
     }
 
-    fn fold_trait_item(&mut self, i: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
+    fn flat_map_trait_item(&mut self, i: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
         let is_const = match i.node {
             ast::TraitItemKind::Const(..) => true,
             ast::TraitItemKind::Method(ast::MethodSig { ref decl, ref header, .. }, _) =>
                 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
             _ => false,
         };
-        self.run(is_const, |s| fold::noop_fold_trait_item(i, s))
+        self.run(is_const, |s| noop_flat_map_trait_item(i, s))
     }
 
-    fn fold_impl_item(&mut self, i: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
+    fn flat_map_impl_item(&mut self, i: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
         let is_const = match i.node {
             ast::ImplItemKind::Const(..) => true,
             ast::ImplItemKind::Method(ast::MethodSig { ref decl, ref header, .. }, _) =>
                 header.constness.node == ast::Constness::Const || Self::should_ignore_fn(decl),
             _ => false,
         };
-        self.run(is_const, |s| fold::noop_fold_impl_item(i, s))
+        self.run(is_const, |s| noop_flat_map_impl_item(i, s))
     }
 
-    fn fold_anon_const(&mut self, c: ast::AnonConst) -> ast::AnonConst {
-        self.run(true, |s| fold::noop_fold_anon_const(c, s))
+    fn visit_anon_const(&mut self, c: &mut ast::AnonConst) {
+        self.run(true, |s| noop_visit_anon_const(c, s))
     }
 
-    fn fold_block(&mut self, b: P<ast::Block>) -> P<ast::Block> {
+    fn visit_block(&mut self, b: &mut P<ast::Block>) {
         fn stmt_to_block(rules: ast::BlockCheckMode,
                          s: Option<ast::Stmt>,
                          sess: &Session) -> ast::Block {
@@ -781,14 +781,14 @@ impl<'a> fold::Folder for ReplaceBodyWithLoop<'a> {
         };
 
         if self.within_static_or_const {
-            fold::noop_fold_block(b, self)
+            noop_visit_block(b, self)
         } else {
-            b.map(|b| {
+            visit_clobber(b.deref_mut(), |b| {
                 let mut stmts = vec![];
                 for s in b.stmts {
                     let old_blocks = self.nested_blocks.replace(vec![]);
 
-                    stmts.extend(self.fold_stmt(s).into_iter().filter(|s| s.is_item()));
+                    stmts.extend(self.flat_map_stmt(s).into_iter().filter(|s| s.is_item()));
 
                     // we put a Some in there earlier with that replace(), so this is valid
                     let new_blocks = self.nested_blocks.take().unwrap();
@@ -819,9 +819,9 @@ impl<'a> fold::Folder for ReplaceBodyWithLoop<'a> {
     }
 
     // in general the pretty printer processes unexpanded code, so
-    // we override the default `fold_mac` method which panics.
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
-        fold::noop_fold_mac(mac, self)
+    // we override the default `visit_mac` method which panics.
+    fn visit_mac(&mut self, mac: &mut ast::Mac) {
+        noop_visit_mac(mac, self)
     }
 }
 
@@ -890,12 +890,9 @@ fn print_flowgraph<'a, 'tcx, W: Write>(variants: Vec<borrowck_dot::Variant>,
     }
 }
 
-pub fn fold_crate(sess: &Session, krate: ast::Crate, ppm: PpMode) -> ast::Crate {
+pub fn visit_crate(sess: &Session, krate: &mut ast::Crate, ppm: PpMode) {
     if let PpmSource(PpmEveryBodyLoops) = ppm {
-        let mut fold = ReplaceBodyWithLoop::new(sess);
-        fold.fold_crate(krate)
-    } else {
-        krate
+        ReplaceBodyWithLoop::new(sess).visit_crate(krate);
     }
 }
 
@@ -959,7 +956,6 @@ pub fn print_after_parsing(sess: &Session,
 pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
                                                 cstore: &'tcx CStore,
                                                 hir_map: &hir_map::Map<'tcx>,
-                                                analysis: &ty::CrateAnalysis,
                                                 resolutions: &Resolutions,
                                                 input: &Input,
                                                 krate: &ast::Crate,
@@ -972,7 +968,6 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
         print_with_analysis(sess,
                             cstore,
                             hir_map,
-                            analysis,
                             resolutions,
                             crate_name,
                             output_filenames,
@@ -1010,7 +1005,6 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
                 s.call_with_pp_support_hir(sess,
                                            cstore,
                                            hir_map,
-                                           analysis,
                                            resolutions,
                                            output_filenames,
                                            crate_name,
@@ -1033,7 +1027,6 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
                 s.call_with_pp_support_hir(sess,
                                            cstore,
                                            hir_map,
-                                           analysis,
                                            resolutions,
                                            output_filenames,
                                            crate_name,
@@ -1048,7 +1041,6 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
                 s.call_with_pp_support_hir(sess,
                                            cstore,
                                            hir_map,
-                                           analysis,
                                            resolutions,
                                            output_filenames,
                                            crate_name,
@@ -1081,7 +1073,6 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
                 s.call_with_pp_support_hir(sess,
                                            cstore,
                                            hir_map,
-                                           analysis,
                                            resolutions,
                                            output_filenames,
                                            crate_name,
@@ -1103,13 +1094,12 @@ pub fn print_after_hir_lowering<'tcx, 'a: 'tcx>(sess: &'a Session,
 }
 
 // In an ideal world, this would be a public function called by the driver after
-// analsysis is performed. However, we want to call `phase_3_run_analysis_passes`
+// analysis is performed. However, we want to call `phase_3_run_analysis_passes`
 // with a different callback than the standard driver, so that isn't easy.
 // Instead, we call that function ourselves.
 fn print_with_analysis<'tcx, 'a: 'tcx>(sess: &'a Session,
                                        cstore: &'a CStore,
                                        hir_map: &hir_map::Map<'tcx>,
-                                       analysis: &ty::CrateAnalysis,
                                        resolutions: &Resolutions,
                                        crate_name: &str,
                                        output_filenames: &OutputFilenames,
@@ -1134,12 +1124,11 @@ fn print_with_analysis<'tcx, 'a: 'tcx>(sess: &'a Session,
                                                      sess,
                                                      cstore,
                                                      hir_map.clone(),
-                                                     analysis.clone(),
                                                      resolutions.clone(),
                                                      &mut arenas,
                                                      crate_name,
                                                      output_filenames,
-                                                     |tcx, _, _, _| {
+                                                     |tcx, _, _| {
         match ppm {
             PpmMir | PpmMirCFG => {
                 if let Some(nodeid) = nodeid {
diff --git a/src/librustc_driver/test.rs b/src/librustc_driver/test.rs
index afcf08632a4f0..2ec755bd62691 100644
--- a/src/librustc_driver/test.rs
+++ b/src/librustc_driver/test.rs
@@ -1,4 +1,4 @@
-//! # Standalone Tests for the Inference Module
+//! Standalone tests for the inference module.
 
 use driver;
 use errors;
@@ -508,8 +508,8 @@ fn subst_ty_renumber_bound() {
     })
 }
 
-/// Test substituting a bound region into a function, which introduces another level of binding.
-/// This requires adjusting the Debruijn index.
+/// Tests substituting a bound region into a function, which introduces another level of binding.
+/// This requires adjusting the De Bruijn index.
 #[test]
 fn subst_ty_renumber_some_bounds() {
     test_env(EMPTY_SOURCE_STR, errors(&[]), |env| {
@@ -544,7 +544,7 @@ fn subst_ty_renumber_some_bounds() {
     })
 }
 
-/// Test that we correctly compute whether a type has escaping regions or not.
+/// Tests that we correctly compute whether a type has escaping regions or not.
 #[test]
 fn escaping() {
     test_env(EMPTY_SOURCE_STR, errors(&[]), |mut env| {
@@ -571,7 +571,7 @@ fn escaping() {
     })
 }
 
-/// Test applying a substitution where the value being substituted for an early-bound region is a
+/// Tests applying a substitution where the value being substituted for an early-bound region is a
 /// late-bound region.
 #[test]
 fn subst_region_renumber_region() {
diff --git a/src/librustc_errors/Cargo.toml b/src/librustc_errors/Cargo.toml
index b24f8ddf4d9f7..02c011857bd2a 100644
--- a/src/librustc_errors/Cargo.toml
+++ b/src/librustc_errors/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_errors"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_errors"
diff --git a/src/librustc_errors/diagnostic.rs b/src/librustc_errors/diagnostic.rs
index 3fa391c84ab25..851b19e8177b5 100644
--- a/src/librustc_errors/diagnostic.rs
+++ b/src/librustc_errors/diagnostic.rs
@@ -1,11 +1,12 @@
-use CodeSuggestion;
-use SubstitutionPart;
-use Substitution;
-use Applicability;
-use Level;
+use crate::CodeSuggestion;
+use crate::SuggestionStyle;
+use crate::SubstitutionPart;
+use crate::Substitution;
+use crate::Applicability;
+use crate::Level;
+use crate::snippet::Style;
 use std::fmt;
 use syntax_pos::{MultiSpan, Span};
-use snippet::Style;
 
 #[must_use]
 #[derive(Clone, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
@@ -118,7 +119,7 @@ impl Diagnostic {
         self.level == Level::Cancelled
     }
 
-    /// Add a span/label to be included in the resulting snippet.
+    /// Adds a span/label to be included in the resulting snippet.
     /// This is pushed onto the `MultiSpan` that was created when the
     /// diagnostic was first built. If you don't call this function at
     /// all, and you just supplied a `Span` to create the diagnostic,
@@ -229,44 +230,72 @@ impl Diagnostic {
         self
     }
 
-    /// Prints out a message with a suggested edit of the code. If the suggestion is presented
-    /// inline it will only show the text message and not the text.
+    pub fn multipart_suggestion(
+        &mut self,
+        msg: &str,
+        suggestion: Vec<(Span, String)>,
+        applicability: Applicability,
+    ) -> &mut Self {
+        self.suggestions.push(CodeSuggestion {
+            substitutions: vec![Substitution {
+                parts: suggestion
+                    .into_iter()
+                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
+                    .collect(),
+            }],
+            msg: msg.to_owned(),
+            style: SuggestionStyle::ShowCode,
+            applicability,
+        });
+        self
+    }
+
+    /// Prints out a message with for a multipart suggestion without showing the suggested code.
     ///
-    /// See `CodeSuggestion` for more information.
-    #[deprecated(note = "Use `span_suggestion_short_with_applicability`")]
-    pub fn span_suggestion_short(&mut self, sp: Span, msg: &str, suggestion: String) -> &mut Self {
+    /// This is intended to be used for suggestions that are obvious in what the changes need to
+    /// be from the message, showing the span label inline would be visually unpleasant
+    /// (marginally overlapping spans or multiline spans) and showing the snippet window wouldn't
+    /// improve understandability.
+    pub fn tool_only_multipart_suggestion(
+        &mut self,
+        msg: &str,
+        suggestion: Vec<(Span, String)>,
+        applicability: Applicability,
+    ) -> &mut Self {
         self.suggestions.push(CodeSuggestion {
             substitutions: vec![Substitution {
-                parts: vec![SubstitutionPart {
-                    snippet: suggestion,
-                    span: sp,
-                }],
+                parts: suggestion
+                    .into_iter()
+                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
+                    .collect(),
             }],
             msg: msg.to_owned(),
-            show_code_when_inline: false,
-            applicability: Applicability::Unspecified,
+            style: SuggestionStyle::CompletelyHidden,
+            applicability,
         });
         self
     }
 
     /// Prints out a message with a suggested edit of the code.
     ///
-    /// In case of short messages and a simple suggestion,
-    /// rustc displays it as a label like
+    /// In case of short messages and a simple suggestion, rustc displays it as a label:
     ///
-    /// "try adding parentheses: `(tup.0).1`"
+    /// ```text
+    /// try adding parentheses: `(tup.0).1`
+    /// ```
     ///
     /// The message
     ///
     /// * should not end in any punctuation (a `:` is added automatically)
-    /// * should not be a question
-    /// * should not contain any parts like "the following", "as shown"
+    /// * should not be a question (avoid language like "did you mean")
+    /// * should not contain any phrases like "the following", "as shown", etc.
     /// * may look like "to do xyz, use" or "to do xyz, use abc"
-    /// * may contain a name of a function, variable or type, but not whole expressions
+    /// * may contain a name of a function, variable, or type, but not whole expressions
     ///
     /// See `CodeSuggestion` for more information.
-    #[deprecated(note = "Use `span_suggestion_with_applicability`")]
-    pub fn span_suggestion(&mut self, sp: Span, msg: &str, suggestion: String) -> &mut Self {
+    pub fn span_suggestion(&mut self, sp: Span, msg: &str,
+                                       suggestion: String,
+                                       applicability: Applicability) -> &mut Self {
         self.suggestions.push(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart {
@@ -275,67 +304,37 @@ impl Diagnostic {
                 }],
             }],
             msg: msg.to_owned(),
-            show_code_when_inline: true,
-            applicability: Applicability::Unspecified,
-        });
-        self
-    }
-
-    pub fn multipart_suggestion_with_applicability(
-        &mut self,
-        msg: &str,
-        suggestion: Vec<(Span, String)>,
-        applicability: Applicability,
-    ) -> &mut Self {
-        self.suggestions.push(CodeSuggestion {
-            substitutions: vec![Substitution {
-                parts: suggestion
-                    .into_iter()
-                    .map(|(span, snippet)| SubstitutionPart { snippet, span })
-                    .collect(),
-            }],
-            msg: msg.to_owned(),
-            show_code_when_inline: true,
+            style: SuggestionStyle::ShowCode,
             applicability,
         });
         self
     }
 
-    #[deprecated(note = "Use `multipart_suggestion_with_applicability`")]
-    pub fn multipart_suggestion(
-        &mut self,
-        msg: &str,
-        suggestion: Vec<(Span, String)>,
-    ) -> &mut Self {
-        self.multipart_suggestion_with_applicability(
-            msg,
-            suggestion,
-            Applicability::Unspecified,
-        )
-    }
-
     /// Prints out a message with multiple suggested edits of the code.
-    #[deprecated(note = "Use `span_suggestions_with_applicability`")]
-    pub fn span_suggestions(&mut self, sp: Span, msg: &str, suggestions: Vec<String>) -> &mut Self {
+    pub fn span_suggestions(&mut self, sp: Span, msg: &str,
+        suggestions: impl Iterator<Item = String>, applicability: Applicability) -> &mut Self
+    {
         self.suggestions.push(CodeSuggestion {
-            substitutions: suggestions.into_iter().map(|snippet| Substitution {
+            substitutions: suggestions.map(|snippet| Substitution {
                 parts: vec![SubstitutionPart {
                     snippet,
                     span: sp,
                 }],
             }).collect(),
             msg: msg.to_owned(),
-            show_code_when_inline: true,
-            applicability: Applicability::Unspecified,
+            style: SuggestionStyle::ShowCode,
+            applicability,
         });
         self
     }
 
-    /// This is a suggestion that may contain mistakes or fillers and should
-    /// be read and understood by a human.
-    pub fn span_suggestion_with_applicability(&mut self, sp: Span, msg: &str,
-                                       suggestion: String,
-                                       applicability: Applicability) -> &mut Self {
+    /// Prints out a message with a suggested edit of the code. If the suggestion is presented
+    /// inline, it will only show the message and not the suggestion.
+    ///
+    /// See `CodeSuggestion` for more information.
+    pub fn span_suggestion_short(
+        &mut self, sp: Span, msg: &str, suggestion: String, applicability: Applicability
+    ) -> &mut Self {
         self.suggestions.push(CodeSuggestion {
             substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart {
@@ -344,30 +343,40 @@ impl Diagnostic {
                 }],
             }],
             msg: msg.to_owned(),
-            show_code_when_inline: true,
+            style: SuggestionStyle::HideCodeInline,
             applicability,
         });
         self
     }
 
-    pub fn span_suggestions_with_applicability(&mut self, sp: Span, msg: &str,
-        suggestions: impl Iterator<Item = String>, applicability: Applicability) -> &mut Self
-    {
+    /// Prints out a message with for a suggestion without showing the suggested code.
+    ///
+    /// This is intended to be used for suggestions that are obvious in what the changes need to
+    /// be from the message, showing the span label inline would be visually unpleasant
+    /// (marginally overlapping spans or multiline spans) and showing the snippet window wouldn't
+    /// improve understandability.
+    pub fn span_suggestion_hidden(
+        &mut self, sp: Span, msg: &str, suggestion: String, applicability: Applicability
+    ) -> &mut Self {
         self.suggestions.push(CodeSuggestion {
-            substitutions: suggestions.map(|snippet| Substitution {
+            substitutions: vec![Substitution {
                 parts: vec![SubstitutionPart {
-                    snippet,
+                    snippet: suggestion,
                     span: sp,
                 }],
-            }).collect(),
+            }],
             msg: msg.to_owned(),
-            show_code_when_inline: true,
+            style: SuggestionStyle::HideCodeInline,
             applicability,
         });
         self
     }
 
-    pub fn span_suggestion_short_with_applicability(
+    /// Adds a suggestion to the json output, but otherwise remains silent/undisplayed in the cli.
+    ///
+    /// This is intended to be used for suggestions that are *very* obvious in what the changes
+    /// need to be from the message, but we still want other tools to be able to apply them.
+    pub fn tool_only_span_suggestion(
         &mut self, sp: Span, msg: &str, suggestion: String, applicability: Applicability
     ) -> &mut Self {
         self.suggestions.push(CodeSuggestion {
@@ -378,7 +387,7 @@ impl Diagnostic {
                 }],
             }],
             msg: msg.to_owned(),
-            show_code_when_inline: false,
+            style: SuggestionStyle::CompletelyHidden,
             applicability: applicability,
         });
         self
diff --git a/src/librustc_errors/diagnostic_builder.rs b/src/librustc_errors/diagnostic_builder.rs
index 7449b2b758302..8a30790174d45 100644
--- a/src/librustc_errors/diagnostic_builder.rs
+++ b/src/librustc_errors/diagnostic_builder.rs
@@ -1,14 +1,15 @@
-use Diagnostic;
-use DiagnosticId;
-use DiagnosticStyledString;
-use Applicability;
+use crate::Diagnostic;
+use crate::DiagnosticId;
+use crate::DiagnosticStyledString;
+use crate::Applicability;
 
-use Level;
-use Handler;
+use crate::Level;
+use crate::Handler;
 use std::fmt::{self, Debug};
 use std::ops::{Deref, DerefMut};
 use std::thread::panicking;
 use syntax_pos::{MultiSpan, Span};
+use log::debug;
 
 /// Used for emitting structured error messages and other diagnostic information.
 ///
@@ -25,7 +26,7 @@ pub struct DiagnosticBuilder<'a> {
 
 /// In general, the `DiagnosticBuilder` uses deref to allow access to
 /// the fields and methods of the embedded `diagnostic` in a
-/// transparent way.  *However,* many of the methods are intended to
+/// transparent way. *However,* many of the methods are intended to
 /// be used in a chained way, and hence ought to return `self`. In
 /// that case, we can't just naively forward to the method on the
 /// `diagnostic`, because the return type would be a `&Diagnostic`
@@ -33,18 +34,24 @@ pub struct DiagnosticBuilder<'a> {
 /// it easy to declare such methods on the builder.
 macro_rules! forward {
     // Forward pattern for &self -> &Self
-    (pub fn $n:ident(&self, $($name:ident: $ty:ty),* $(,)*) -> &Self) => {
+    (
+        $(#[$attrs:meta])*
+        pub fn $n:ident(&self, $($name:ident: $ty:ty),* $(,)*) -> &Self
+    ) => {
+        $(#[$attrs])*
         pub fn $n(&self, $($name: $ty),*) -> &Self {
-            #[allow(deprecated)]
             self.diagnostic.$n($($name),*);
             self
         }
     };
 
     // Forward pattern for &mut self -> &mut Self
-    (pub fn $n:ident(&mut self, $($name:ident: $ty:ty),* $(,)*) -> &mut Self) => {
+    (
+        $(#[$attrs:meta])*
+        pub fn $n:ident(&mut self, $($name:ident: $ty:ty),* $(,)*) -> &mut Self
+    ) => {
+        $(#[$attrs])*
         pub fn $n(&mut self, $($name: $ty),*) -> &mut Self {
-            #[allow(deprecated)]
             self.diagnostic.$n($($name),*);
             self
         }
@@ -52,12 +59,16 @@ macro_rules! forward {
 
     // Forward pattern for &mut self -> &mut Self, with S: Into<MultiSpan>
     // type parameter. No obvious way to make this more generic.
-    (pub fn $n:ident<S: Into<MultiSpan>>(
-                    &mut self,
-                    $($name:ident: $ty:ty),*
-                    $(,)*) -> &mut Self) => {
+    (
+        $(#[$attrs:meta])*
+        pub fn $n:ident<S: Into<MultiSpan>>(
+            &mut self,
+            $($name:ident: $ty:ty),*
+            $(,)*
+        ) -> &mut Self
+    ) => {
+        $(#[$attrs])*
         pub fn $n<S: Into<MultiSpan>>(&mut self, $($name: $ty),*) -> &mut Self {
-            #[allow(deprecated)]
             self.diagnostic.$n($($name),*);
             self
         }
@@ -101,8 +112,8 @@ impl<'a> DiagnosticBuilder<'a> {
         // implements `Drop`.
         let diagnostic;
         unsafe {
-            diagnostic = ::std::ptr::read(&self.diagnostic);
-            ::std::mem::forget(self);
+            diagnostic = std::ptr::read(&self.diagnostic);
+            std::mem::forget(self);
         };
         // Logging here is useful to help track down where in logs an error was
         // actually emitted.
@@ -139,7 +150,7 @@ impl<'a> DiagnosticBuilder<'a> {
         self.cancel();
     }
 
-    /// Add a span/label to be included in the resulting snippet.
+    /// Adds a span/label to be included in the resulting snippet.
     /// This is pushed onto the `MultiSpan` that was created when the
     /// diagnostic was first built. If you don't call this function at
     /// all, and you just supplied a `Span` to create the diagnostic,
@@ -177,44 +188,33 @@ impl<'a> DiagnosticBuilder<'a> {
                                                   msg: &str,
                                                   ) -> &mut Self);
 
-    #[deprecated(note = "Use `span_suggestion_short_with_applicability`")]
-    forward!(pub fn span_suggestion_short(
-                                      &mut self,
-                                      sp: Span,
-                                      msg: &str,
-                                      suggestion: String,
-                                      ) -> &mut Self);
+    pub fn multipart_suggestion(
+        &mut self,
+        msg: &str,
+        suggestion: Vec<(Span, String)>,
+        applicability: Applicability,
+    ) -> &mut Self {
+        if !self.allow_suggestions {
+            return self
+        }
+        self.diagnostic.multipart_suggestion(
+            msg,
+            suggestion,
+            applicability,
+        );
+        self
+    }
 
-    #[deprecated(note = "Use `multipart_suggestion_with_applicability`")]
-    forward!(pub fn multipart_suggestion(
+    pub fn tool_only_multipart_suggestion(
         &mut self,
         msg: &str,
         suggestion: Vec<(Span, String)>,
-    ) -> &mut Self);
-
-    #[deprecated(note = "Use `span_suggestion_with_applicability`")]
-    forward!(pub fn span_suggestion(&mut self,
-                                    sp: Span,
-                                    msg: &str,
-                                    suggestion: String,
-                                    ) -> &mut Self);
-
-    #[deprecated(note = "Use `span_suggestions_with_applicability`")]
-    forward!(pub fn span_suggestions(&mut self,
-                                     sp: Span,
-                                     msg: &str,
-                                     suggestions: Vec<String>,
-                                     ) -> &mut Self);
-
-    pub fn multipart_suggestion_with_applicability(&mut self,
-                                              msg: &str,
-                                              suggestion: Vec<(Span, String)>,
-                                              applicability: Applicability,
-                                              ) -> &mut Self {
+        applicability: Applicability,
+    ) -> &mut Self {
         if !self.allow_suggestions {
             return self
         }
-        self.diagnostic.multipart_suggestion_with_applicability(
+        self.diagnostic.tool_only_multipart_suggestion(
             msg,
             suggestion,
             applicability,
@@ -222,16 +222,18 @@ impl<'a> DiagnosticBuilder<'a> {
         self
     }
 
-    pub fn span_suggestion_with_applicability(&mut self,
-                                              sp: Span,
-                                              msg: &str,
-                                              suggestion: String,
-                                              applicability: Applicability)
-                                              -> &mut Self {
+
+    pub fn span_suggestion(
+        &mut self,
+        sp: Span,
+        msg: &str,
+        suggestion: String,
+        applicability: Applicability,
+    ) -> &mut Self {
         if !self.allow_suggestions {
             return self
         }
-        self.diagnostic.span_suggestion_with_applicability(
+        self.diagnostic.span_suggestion(
             sp,
             msg,
             suggestion,
@@ -240,16 +242,17 @@ impl<'a> DiagnosticBuilder<'a> {
         self
     }
 
-    pub fn span_suggestions_with_applicability(&mut self,
-                                               sp: Span,
-                                               msg: &str,
-                                               suggestions: impl Iterator<Item = String>,
-                                               applicability: Applicability)
-                                               -> &mut Self {
+    pub fn span_suggestions(
+        &mut self,
+        sp: Span,
+        msg: &str,
+        suggestions: impl Iterator<Item = String>,
+        applicability: Applicability,
+    ) -> &mut Self {
         if !self.allow_suggestions {
             return self
         }
-        self.diagnostic.span_suggestions_with_applicability(
+        self.diagnostic.span_suggestions(
             sp,
             msg,
             suggestions,
@@ -258,16 +261,17 @@ impl<'a> DiagnosticBuilder<'a> {
         self
     }
 
-    pub fn span_suggestion_short_with_applicability(&mut self,
-                                                    sp: Span,
-                                                    msg: &str,
-                                                    suggestion: String,
-                                                    applicability: Applicability)
-                                                    -> &mut Self {
+    pub fn span_suggestion_short(
+        &mut self,
+        sp: Span,
+        msg: &str,
+        suggestion: String,
+        applicability: Applicability,
+    ) -> &mut Self {
         if !self.allow_suggestions {
             return self
         }
-        self.diagnostic.span_suggestion_short_with_applicability(
+        self.diagnostic.span_suggestion_short(
             sp,
             msg,
             suggestion,
@@ -275,6 +279,45 @@ impl<'a> DiagnosticBuilder<'a> {
         );
         self
     }
+
+    pub fn span_suggestion_hidden(
+        &mut self,
+        sp: Span,
+        msg: &str,
+        suggestion: String,
+        applicability: Applicability,
+    ) -> &mut Self {
+        if !self.allow_suggestions {
+            return self
+        }
+        self.diagnostic.span_suggestion_hidden(
+            sp,
+            msg,
+            suggestion,
+            applicability,
+        );
+        self
+    }
+
+    pub fn tool_only_span_suggestion(
+        &mut self,
+        sp: Span,
+        msg: &str,
+        suggestion: String,
+        applicability: Applicability,
+    ) -> &mut Self {
+        if !self.allow_suggestions {
+            return self
+        }
+        self.diagnostic.tool_only_span_suggestion(
+            sp,
+            msg,
+            suggestion,
+            applicability,
+        );
+        self
+    }
+
     forward!(pub fn set_span<S: Into<MultiSpan>>(&mut self, sp: S) -> &mut Self);
     forward!(pub fn code(&mut self, s: DiagnosticId) -> &mut Self);
 
@@ -313,7 +356,7 @@ impl<'a> DiagnosticBuilder<'a> {
 }
 
 impl<'a> Debug for DiagnosticBuilder<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.diagnostic.fmt(f)
     }
 }
diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 0443b2228e5b4..e9f269b6e2410 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -1,37 +1,38 @@
-use self::Destination::*;
+use Destination::*;
 
 use syntax_pos::{SourceFile, Span, MultiSpan};
 
-use {Level, CodeSuggestion, DiagnosticBuilder, SubDiagnostic, SourceMapperDyn, DiagnosticId};
-use snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
-use styled_buffer::StyledBuffer;
+use crate::{
+    Level, CodeSuggestion, DiagnosticBuilder, SubDiagnostic,
+    SuggestionStyle, SourceMapperDyn, DiagnosticId,
+};
+use crate::snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
+use crate::styled_buffer::StyledBuffer;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
-use atty;
 use std::borrow::Cow;
 use std::io::prelude::*;
 use std::io;
 use std::cmp::{min, Reverse};
 use termcolor::{StandardStream, ColorChoice, ColorSpec, BufferWriter};
 use termcolor::{WriteColor, Color, Buffer};
-use unicode_width;
 
 const ANONYMIZED_LINE_NUM: &str = "LL";
 
 /// Emitter trait for emitting errors.
 pub trait Emitter {
     /// Emit a structured diagnostic.
-    fn emit(&mut self, db: &DiagnosticBuilder);
+    fn emit(&mut self, db: &DiagnosticBuilder<'_>);
 
-    /// Check if should show explanations about "rustc --explain"
+    /// Checks if should show explanations about "rustc --explain"
     fn should_show_explain(&self) -> bool {
         true
     }
 }
 
 impl Emitter for EmitterWriter {
-    fn emit(&mut self, db: &DiagnosticBuilder) {
+    fn emit(&mut self, db: &DiagnosticBuilder<'_>) {
         let mut primary_span = db.span.clone();
         let mut children = db.children.clone();
         let mut suggestions: &[_] = &[];
@@ -45,9 +46,14 @@ impl Emitter for EmitterWriter {
                // don't display long messages as labels
                sugg.msg.split_whitespace().count() < 10 &&
                // don't display multiline suggestions as labels
-               !sugg.substitutions[0].parts[0].snippet.contains('\n') {
+               !sugg.substitutions[0].parts[0].snippet.contains('\n') &&
+               // when this style is set we want the suggestion to be a message, not inline
+               sugg.style != SuggestionStyle::HideCodeAlways &&
+               // trivial suggestion for tooling's sake, never shown
+               sugg.style != SuggestionStyle::CompletelyHidden
+            {
                 let substitution = &sugg.substitutions[0].parts[0].snippet.trim();
-                let msg = if substitution.len() == 0 || !sugg.show_code_when_inline {
+                let msg = if substitution.len() == 0 || sugg.style.hide_inline() {
                     // This substitution is only removal or we explicitly don't want to show the
                     // code inline, don't show it
                     format!("help: {}", sugg.msg)
@@ -674,8 +680,8 @@ impl EmitterWriter {
         //   | |  something about `foo`
         //   | something about `fn foo()`
         annotations_position.sort_by(|a, b| {
-            // Decreasing order
-            a.1.len().cmp(&b.1.len()).reverse()
+            // Decreasing order. When `a` and `b` are the same length, prefer `Primary`.
+            (a.1.len(), !a.1.is_primary).cmp(&(b.1.len(), !b.1.is_primary)).reverse()
         });
 
         // Write the underlines.
@@ -870,7 +876,7 @@ impl EmitterWriter {
         }
     }
 
-    /// Add a left margin to every line but the first, given a padding length and the label being
+    /// Adds a left margin to every line but the first, given a padding length and the label being
     /// displayed, keeping the provided highlighting.
     fn msg_to_buffer(&self,
                      buffer: &mut StyledBuffer,
@@ -897,7 +903,7 @@ impl EmitterWriter {
         //    `max_line_num_len`
         let padding = " ".repeat(padding + label.len() + 5);
 
-        /// Return whether `style`, or the override if present and the style is `NoStyle`.
+        /// Returns `true` if `style`, or the override if present and the style is `NoStyle`.
         fn style_or_override(style: Style, override_style: Option<Style>) -> Style {
             if let Some(o) = override_style {
                 if style == Style::NoStyle {
@@ -944,14 +950,15 @@ impl EmitterWriter {
         }
     }
 
-    fn emit_message_default(&mut self,
-                            msp: &MultiSpan,
-                            msg: &[(String, Style)],
-                            code: &Option<DiagnosticId>,
-                            level: &Level,
-                            max_line_num_len: usize,
-                            is_secondary: bool)
-                            -> io::Result<()> {
+    fn emit_message_default(
+        &mut self,
+        msp: &MultiSpan,
+        msg: &[(String, Style)],
+        code: &Option<DiagnosticId>,
+        level: &Level,
+        max_line_num_len: usize,
+        is_secondary: bool,
+    ) -> io::Result<()> {
         let mut buffer = StyledBuffer::new();
         let header_style = if is_secondary {
             Style::HeaderMsg
@@ -959,7 +966,7 @@ impl EmitterWriter {
             Style::MainHeaderMsg
         };
 
-        if msp.primary_spans().is_empty() && msp.span_labels().is_empty() && is_secondary
+        if !msp.has_primary_spans() && !msp.has_span_labels() && is_secondary
            && !self.short_message {
             // This is a secondary message with no span info
             for _ in 0..max_line_num_len {
@@ -1186,11 +1193,12 @@ impl EmitterWriter {
 
     }
 
-    fn emit_suggestion_default(&mut self,
-                               suggestion: &CodeSuggestion,
-                               level: &Level,
-                               max_line_num_len: usize)
-                               -> io::Result<()> {
+    fn emit_suggestion_default(
+        &mut self,
+        suggestion: &CodeSuggestion,
+        level: &Level,
+        max_line_num_len: usize,
+    ) -> io::Result<()> {
         if let Some(ref sm) = self.sm {
             let mut buffer = StyledBuffer::new();
 
@@ -1200,11 +1208,13 @@ impl EmitterWriter {
                 buffer.append(0, &level_str, Style::Level(level.clone()));
                 buffer.append(0, ": ", Style::HeaderMsg);
             }
-            self.msg_to_buffer(&mut buffer,
-                               &[(suggestion.msg.to_owned(), Style::NoStyle)],
-                               max_line_num_len,
-                               "suggestion",
-                               Some(Style::HeaderMsg));
+            self.msg_to_buffer(
+                &mut buffer,
+                &[(suggestion.msg.to_owned(), Style::NoStyle)],
+                max_line_num_len,
+                "suggestion",
+                Some(Style::HeaderMsg),
+            );
 
             // Render the replacements for each suggestion
             let suggestions = suggestion.splice_lines(&**sm);
@@ -1342,22 +1352,42 @@ impl EmitterWriter {
                 if !self.short_message {
                     for child in children {
                         let span = child.render_span.as_ref().unwrap_or(&child.span);
-                        match self.emit_message_default(&span,
-                                                        &child.styled_message(),
-                                                        &None,
-                                                        &child.level,
-                                                        max_line_num_len,
-                                                        true) {
+                        match self.emit_message_default(
+                            &span,
+                            &child.styled_message(),
+                            &None,
+                            &child.level,
+                            max_line_num_len,
+                            true,
+                        ) {
                             Err(e) => panic!("failed to emit error: {}", e),
                             _ => ()
                         }
                     }
                     for sugg in suggestions {
-                        match self.emit_suggestion_default(sugg,
-                                                           &Level::Help,
-                                                           max_line_num_len) {
-                            Err(e) => panic!("failed to emit error: {}", e),
-                            _ => ()
+                        if sugg.style == SuggestionStyle::CompletelyHidden {
+                            // do not display this suggestion, it is meant only for tools
+                        } else if sugg.style == SuggestionStyle::HideCodeAlways {
+                            match self.emit_message_default(
+                                &MultiSpan::new(),
+                                &[(sugg.msg.to_owned(), Style::HeaderMsg)],
+                                &None,
+                                &Level::Help,
+                                max_line_num_len,
+                                true,
+                            ) {
+                                Err(e) => panic!("failed to emit error: {}", e),
+                                _ => ()
+                            }
+                        } else {
+                            match self.emit_suggestion_default(
+                                sugg,
+                                &Level::Help,
+                                max_line_num_len,
+                            ) {
+                                Err(e) => panic!("failed to emit error: {}", e),
+                                _ => ()
+                            }
                         }
                     }
                 }
@@ -1431,7 +1461,7 @@ fn emit_to_destination(rendered_buffer: &[Vec<StyledString>],
                        dst: &mut Destination,
                        short_message: bool)
                        -> io::Result<()> {
-    use lock;
+    use crate::lock;
 
     let mut dst = dst.writable();
 
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index a074441f8a179..87b4751526835 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -1,6 +1,4 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
@@ -8,21 +6,14 @@
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]
 #![feature(optin_builtin_traits)]
+#![deny(rust_2018_idioms)]
 
-extern crate atty;
-extern crate termcolor;
-#[cfg(unix)]
-extern crate libc;
-#[macro_use]
-extern crate log;
-extern crate rustc_data_structures;
-extern crate serialize as rustc_serialize;
-extern crate syntax_pos;
-extern crate unicode_width;
+#[allow(unused_extern_crates)]
+extern crate serialize as rustc_serialize; // used by deriving
 
 pub use emitter::ColorConfig;
 
-use self::Level::*;
+use Level::*;
 
 use emitter::{Emitter, EmitterWriter};
 
@@ -54,12 +45,51 @@ use syntax_pos::{BytePos,
                  Span,
                  NO_EXPANSION};
 
+/// Indicates the confidence in the correctness of a suggestion.
+///
+/// All suggestions are marked with an `Applicability`. Tools use the applicability of a suggestion
+/// to determine whether it should be automatically applied or if the user should be consulted
+/// before applying the suggestion.
 #[derive(Copy, Clone, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
 pub enum Applicability {
+    /// The suggestion is definitely what the user intended. This suggestion should be
+    /// automatically applied.
     MachineApplicable,
-    HasPlaceholders,
+
+    /// The suggestion may be what the user intended, but it is uncertain. The suggestion should
+    /// result in valid Rust code if it is applied.
     MaybeIncorrect,
-    Unspecified
+
+    /// The suggestion contains placeholders like `(...)` or `{ /* fields */ }`. The suggestion
+    /// cannot be applied automatically because it will not result in valid Rust code. The user
+    /// will need to fill in the placeholders.
+    HasPlaceholders,
+
+    /// The applicability of the suggestion is unknown.
+    Unspecified,
+}
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, RustcEncodable, RustcDecodable)]
+pub enum SuggestionStyle {
+    /// Hide the suggested code when displaying this suggestion inline.
+    HideCodeInline,
+    /// Always hide the suggested code but display the message.
+    HideCodeAlways,
+    /// Do not display this suggestion in the cli output, it is only meant for tools.
+    CompletelyHidden,
+    /// Always show the suggested code.
+    /// This will *not* show the code if the suggestion is inline *and* the suggested code is
+    /// empty.
+    ShowCode,
+}
+
+impl SuggestionStyle {
+    fn hide_inline(&self) -> bool {
+        match *self {
+            SuggestionStyle::ShowCode => false,
+            _ => true,
+        }
+    }
 }
 
 #[derive(Clone, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
@@ -87,7 +117,8 @@ pub struct CodeSuggestion {
     /// ```
     pub substitutions: Vec<Substitution>,
     pub msg: String,
-    pub show_code_when_inline: bool,
+    /// Visual representation of this suggestion.
+    pub style: SuggestionStyle,
     /// Whether or not the suggestion is approximate
     ///
     /// Sometimes we may show suggestions with placeholders,
@@ -128,17 +159,18 @@ impl CodeSuggestion {
         use syntax_pos::{CharPos, Loc, Pos};
 
         fn push_trailing(buf: &mut String,
-                         line_opt: Option<&Cow<str>>,
+                         line_opt: Option<&Cow<'_, str>>,
                          lo: &Loc,
                          hi_opt: Option<&Loc>) {
             let (lo, hi_opt) = (lo.col.to_usize(), hi_opt.map(|hi| hi.col.to_usize()));
             if let Some(line) = line_opt {
                 if let Some(lo) = line.char_indices().map(|(i, _)| i).nth(lo) {
                     let hi_opt = hi_opt.and_then(|hi| line.char_indices().map(|(i, _)| i).nth(hi));
-                    buf.push_str(match hi_opt {
-                        Some(hi) => &line[lo..hi],
-                        None => &line[lo..],
-                    });
+                    match hi_opt {
+                        Some(hi) if hi > lo => buf.push_str(&line[lo..hi]),
+                        Some(_) => (),
+                        None => buf.push_str(&line[lo..]),
+                    }
                 }
                 if let None = hi_opt {
                     buf.push('\n');
@@ -230,7 +262,7 @@ impl FatalError {
 }
 
 impl fmt::Display for FatalError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "parser fatal error")
     }
 }
@@ -247,7 +279,7 @@ impl error::Error for FatalError {
 pub struct ExplicitBug;
 
 impl fmt::Display for ExplicitBug {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "parser internal bug")
     }
 }
@@ -382,7 +414,7 @@ impl Handler {
 
     /// Resets the diagnostic error count as well as the cached emitted diagnostics.
     ///
-    /// NOTE: DO NOT call this function from rustc. It is only meant to be called from external
+    /// NOTE: *do not* call this function from rustc. It is only meant to be called from external
     /// tools that want to reuse a `Parser` cleaning the previously emitted diagnostics as well as
     /// the overall count of emitted error diagnostics.
     pub fn reset_err_count(&self) {
@@ -479,7 +511,7 @@ impl Handler {
         DiagnosticBuilder::new(self, Level::Fatal, msg)
     }
 
-    pub fn cancel(&self, err: &mut DiagnosticBuilder) {
+    pub fn cancel(&self, err: &mut DiagnosticBuilder<'_>) {
         err.cancel();
     }
 
@@ -681,12 +713,12 @@ impl Handler {
         self.taught_diagnostics.borrow_mut().insert(code.clone())
     }
 
-    pub fn force_print_db(&self, mut db: DiagnosticBuilder) {
+    pub fn force_print_db(&self, mut db: DiagnosticBuilder<'_>) {
         self.emitter.borrow_mut().emit(&db);
         db.cancel();
     }
 
-    fn emit_db(&self, db: &DiagnosticBuilder) {
+    fn emit_db(&self, db: &DiagnosticBuilder<'_>) {
         let diagnostic = &**db;
 
         TRACK_DIAGNOSTICS.with(|track_diagnostics| {
@@ -732,7 +764,7 @@ pub enum Level {
 }
 
 impl fmt::Display for Level {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.to_str().fmt(f)
     }
 }
diff --git a/src/librustc_errors/snippet.rs b/src/librustc_errors/snippet.rs
index da1da77f398a9..0c62ff0ff89b2 100644
--- a/src/librustc_errors/snippet.rs
+++ b/src/librustc_errors/snippet.rs
@@ -1,6 +1,6 @@
 // Code for annotating snippets.
 
-use Level;
+use crate::Level;
 
 #[derive(Clone, Debug, PartialOrd, Ord, PartialEq, Eq)]
 pub struct Line {
diff --git a/src/librustc_errors/styled_buffer.rs b/src/librustc_errors/styled_buffer.rs
index 880f09e75e32e..6e03618d2b0b5 100644
--- a/src/librustc_errors/styled_buffer.rs
+++ b/src/librustc_errors/styled_buffer.rs
@@ -1,6 +1,6 @@
 // Code for creating styled buffers
 
-use snippet::{Style, StyledString};
+use crate::snippet::{Style, StyledString};
 
 #[derive(Debug)]
 pub struct StyledBuffer {
diff --git a/src/librustc_fs_util/Cargo.toml b/src/librustc_fs_util/Cargo.toml
index e40b44204b349..47918643f31fe 100644
--- a/src/librustc_fs_util/Cargo.toml
+++ b/src/librustc_fs_util/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_fs_util"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_fs_util"
diff --git a/src/librustc_fs_util/lib.rs b/src/librustc_fs_util/lib.rs
index 74ff121f80385..ce63bcafd797c 100644
--- a/src/librustc_fs_util/lib.rs
+++ b/src/librustc_fs_util/lib.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 use std::path::{Path, PathBuf};
 use std::ffi::CString;
 use std::fs;
@@ -56,7 +58,7 @@ pub enum LinkOrCopy {
     Copy,
 }
 
-/// Copy `p` into `q`, preferring to use hard-linking if possible. If
+/// Copies `p` into `q`, preferring to use hard-linking if possible. If
 /// `q` already exists, it is removed first.
 /// The result indicates which of the two operations has been performed.
 pub fn link_or_copy<P: AsRef<Path>, Q: AsRef<Path>>(p: P, q: Q) -> io::Result<LinkOrCopy> {
diff --git a/src/librustc_incremental/Cargo.toml b/src/librustc_incremental/Cargo.toml
index b8519ee1ab1a5..10b448b7fec3f 100644
--- a/src/librustc_incremental/Cargo.toml
+++ b/src/librustc_incremental/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_incremental"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_incremental"
diff --git a/src/librustc_incremental/assert_dep_graph.rs b/src/librustc_incremental/assert_dep_graph.rs
index 57ab48493fa93..fe44e0cbe6143 100644
--- a/src/librustc_incremental/assert_dep_graph.rs
+++ b/src/librustc_incremental/assert_dep_graph.rs
@@ -12,7 +12,7 @@
 //! In this code, we report errors on each `rustc_if_this_changed`
 //! annotation. If a path exists in all cases, then we would report
 //! "all path(s) exist". Otherwise, we report: "no path to `foo`" for
-//! each case where no path exists.  `compile-fail` tests can then be
+//! each case where no path exists. `compile-fail` tests can then be
 //! used to check when paths exist or do not.
 //!
 //! The full form of the `rustc_if_this_changed` annotation is
@@ -217,7 +217,7 @@ fn check_paths<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
 }
 
-fn dump_graph(tcx: TyCtxt) {
+fn dump_graph(tcx: TyCtxt<'_, '_, '_>) {
     let path: String = env::var("RUST_DEP_GRAPH").unwrap_or_else(|_| "dep_graph".to_string());
     let query = tcx.dep_graph.query();
 
@@ -261,11 +261,11 @@ pub struct GraphvizDepGraph<'q>(FxHashSet<&'q DepNode>,
 impl<'a, 'tcx, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
     type Node = &'q DepNode;
     type Edge = (&'q DepNode, &'q DepNode);
-    fn nodes(&self) -> dot::Nodes<&'q DepNode> {
+    fn nodes(&self) -> dot::Nodes<'_, &'q DepNode> {
         let nodes: Vec<_> = self.0.iter().cloned().collect();
         nodes.into()
     }
-    fn edges(&self) -> dot::Edges<(&'q DepNode, &'q DepNode)> {
+    fn edges(&self) -> dot::Edges<'_, (&'q DepNode, &'q DepNode)> {
         self.1[..].into()
     }
     fn source(&self, edge: &(&'q DepNode, &'q DepNode)) -> &'q DepNode {
@@ -279,10 +279,10 @@ impl<'a, 'tcx, 'q> dot::GraphWalk<'a> for GraphvizDepGraph<'q> {
 impl<'a, 'tcx, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
     type Node = &'q DepNode;
     type Edge = (&'q DepNode, &'q DepNode);
-    fn graph_id(&self) -> dot::Id {
+    fn graph_id(&self) -> dot::Id<'_> {
         dot::Id::new("DependencyGraph").unwrap()
     }
-    fn node_id(&self, n: &&'q DepNode) -> dot::Id {
+    fn node_id(&self, n: &&'q DepNode) -> dot::Id<'_> {
         let s: String =
             format!("{:?}", n).chars()
                               .map(|c| if c == '_' || c.is_alphanumeric() { c } else { '_' })
@@ -290,7 +290,7 @@ impl<'a, 'tcx, 'q> dot::Labeller<'a> for GraphvizDepGraph<'q> {
         debug!("n={:?} s={:?}", n, s);
         dot::Id::new(s).unwrap()
     }
-    fn node_label(&self, n: &&'q DepNode) -> dot::LabelText {
+    fn node_label(&self, n: &&'q DepNode) -> dot::LabelText<'_> {
         dot::LabelText::label(format!("{:?}", n))
     }
 }
diff --git a/src/librustc_incremental/lib.rs b/src/librustc_incremental/lib.rs
index ae2e6e0b94cfc..346ddaa485804 100644
--- a/src/librustc_incremental/lib.rs
+++ b/src/librustc_incremental/lib.rs
@@ -1,24 +1,19 @@
 //! Support for serializing the dep-graph and reloading it.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(nll)]
 #![feature(specialization)]
 
 #![recursion_limit="256"]
 
-extern crate graphviz;
+#![deny(rust_2018_idioms)]
+
 #[macro_use] extern crate rustc;
-extern crate rustc_data_structures;
-extern crate serialize as rustc_serialize;
-extern crate rand;
-extern crate rustc_fs_util;
+#[allow(unused_extern_crates)]
+extern crate serialize as rustc_serialize; // used by deriving
 
 #[macro_use] extern crate log;
-extern crate syntax;
-extern crate syntax_pos;
 
 mod assert_dep_graph;
 pub mod assert_module_sources;
diff --git a/src/librustc_incremental/persist/dirty_clean.rs b/src/librustc_incremental/persist/dirty_clean.rs
index 3ff4d2ec38dff..c13a3533032a8 100644
--- a/src/librustc_incremental/persist/dirty_clean.rs
+++ b/src/librustc_incremental/persist/dirty_clean.rs
@@ -5,14 +5,13 @@
 //!
 //! - `#[rustc_clean(cfg="rev2", except="TypeckTables")]` if we are
 //!   in `#[cfg(rev2)]`, then the fingerprints associated with
-//!   `DepNode::TypeckTables(X)` must be DIFFERENT (`X` is the def-id of the
+//!   `DepNode::TypeckTables(X)` must be DIFFERENT (`X` is the `DefId` of the
 //!   current node).
 //! - `#[rustc_clean(cfg="rev2")]` same as above, except that the
 //!   fingerprints must be the SAME (along with all other fingerprints).
 //!
 //! Errors are reported if we are in the suitable configuration but
 //! the required condition is not met.
-//!
 
 use std::iter::FromIterator;
 use std::vec::Vec;
@@ -67,11 +66,11 @@ const BASE_IMPL: &[&str] = &[
     label_strs::ImplTraitRef,
 ];
 
-/// DepNodes for MirValidated/Optimized, which is relevant in "executable"
+/// DepNodes for MirBuilt/Optimized, which is relevant in "executable"
 /// code, i.e., functions+methods
 const BASE_MIR: &[&str] = &[
     label_strs::MirOptimized,
-    label_strs::MirValidated,
+    label_strs::MirBuilt,
 ];
 
 /// Struct, Enum and Union DepNodes
@@ -84,7 +83,7 @@ const BASE_STRUCT: &[&str] = &[
     label_strs::TypeOfItem,
 ];
 
-/// Trait Definition DepNodes
+/// Trait definition `DepNode`s.
 const BASE_TRAIT_DEF: &[&str] = &[
     label_strs::AssociatedItemDefIds,
     label_strs::GenericsOfItem,
@@ -95,7 +94,7 @@ const BASE_TRAIT_DEF: &[&str] = &[
     label_strs::TraitImpls,
 ];
 
-/// extra DepNodes for methods (+fn)
+/// Extra `DepNode`s for functions and methods.
 const EXTRA_ASSOCIATED: &[&str] = &[
     label_strs::AssociatedItems,
 ];
@@ -126,14 +125,14 @@ const LABELS_CONST_IN_TRAIT: &[&[&str]] = &[
     EXTRA_TRAIT,
 ];
 
-/// Function DepNode
+/// Function `DepNode`s.
 const LABELS_FN: &[&[&str]] = &[
     BASE_HIR,
     BASE_MIR,
     BASE_FN,
 ];
 
-/// Method DepNodes
+/// Method `DepNode`s.
 const LABELS_FN_IN_IMPL: &[&[&str]] = &[
     BASE_HIR,
     BASE_MIR,
@@ -141,7 +140,7 @@ const LABELS_FN_IN_IMPL: &[&[&str]] = &[
     EXTRA_ASSOCIATED,
 ];
 
-/// Trait-Method DepNodes
+/// Trait method `DepNode`s.
 const LABELS_FN_IN_TRAIT: &[&[&str]] = &[
     BASE_HIR,
     BASE_MIR,
@@ -150,24 +149,24 @@ const LABELS_FN_IN_TRAIT: &[&[&str]] = &[
     EXTRA_TRAIT,
 ];
 
-/// For generic cases like inline-assembly/mod/etc
+/// For generic cases like inline-assembly, modules, etc.
 const LABELS_HIR_ONLY: &[&[&str]] = &[
     BASE_HIR,
 ];
 
-/// Impl DepNodes
+/// Impl `DepNode`s.
 const LABELS_IMPL: &[&[&str]] = &[
     BASE_HIR,
     BASE_IMPL,
 ];
 
-/// Abstract Data Type (Struct, Enum, Unions) DepNodes
+/// Abstract data type (struct, enum, union) `DepNode`s.
 const LABELS_ADT: &[&[&str]] = &[
     BASE_HIR,
     BASE_STRUCT,
 ];
 
-/// Trait Definition DepNodes
+/// Trait definition `DepNode`s.
 #[allow(dead_code)]
 const LABELS_TRAIT: &[&[&str]] = &[
     BASE_HIR,
@@ -269,7 +268,7 @@ impl<'a, 'tcx> DirtyCleanVisitor<'a, 'tcx> {
         Some(assertion)
     }
 
-    /// Get the "auto" assertion on pre-validated attr, along with the `except` labels
+    /// Gets the "auto" assertion on pre-validated attr, along with the `except` labels.
     fn assertion_auto(&mut self, item_id: ast::NodeId, attr: &Attribute, is_clean: bool)
         -> Assertion
     {
@@ -538,7 +537,7 @@ impl<'a, 'tcx> ItemLikeVisitor<'tcx> for DirtyCleanVisitor<'a, 'tcx> {
 ///
 /// Also make sure that the `label` and `except` fields do not
 /// both exist.
-fn check_config(tcx: TyCtxt, attr: &Attribute) -> bool {
+fn check_config(tcx: TyCtxt<'_, '_, '_>, attr: &Attribute) -> bool {
     debug!("check_config(attr={:?})", attr);
     let config = &tcx.sess.parse_sess.config;
     debug!("check_config: config={:?}", config);
@@ -573,7 +572,7 @@ fn check_config(tcx: TyCtxt, attr: &Attribute) -> bool {
     }
 }
 
-fn expect_associated_value(tcx: TyCtxt, item: &NestedMetaItem) -> ast::Name {
+fn expect_associated_value(tcx: TyCtxt<'_, '_, '_>, item: &NestedMetaItem) -> ast::Name {
     if let Some(value) = item.value_str() {
         value
     } else {
diff --git a/src/librustc_incremental/persist/file_format.rs b/src/librustc_incremental/persist/file_format.rs
index 3b88a14f3a2b7..f363f718496fa 100644
--- a/src/librustc_incremental/persist/file_format.rs
+++ b/src/librustc_incremental/persist/file_format.rs
@@ -17,15 +17,15 @@ use std::env;
 use rustc::session::config::nightly_options;
 use rustc_serialize::opaque::Encoder;
 
-/// The first few bytes of files generated by incremental compilation
+/// The first few bytes of files generated by incremental compilation.
 const FILE_MAGIC: &[u8] = b"RSIC";
 
-/// Change this if the header format changes
+/// Change this if the header format changes.
 const HEADER_FORMAT_VERSION: u16 = 0;
 
 /// A version string that hopefully is always different for compiler versions
 /// with different encodings of incremental compilation artifacts. Contains
-/// the git commit hash.
+/// the Git commit hash.
 const RUSTC_VERSION: Option<&str> = option_env!("CFG_VERSION");
 
 pub fn write_file_header(stream: &mut Encoder) {
diff --git a/src/librustc_incremental/persist/fs.rs b/src/librustc_incremental/persist/fs.rs
index ff8b76829eb2e..7dcd5c94bf298 100644
--- a/src/librustc_incremental/persist/fs.rs
+++ b/src/librustc_incremental/persist/fs.rs
@@ -444,7 +444,7 @@ fn copy_files(sess: &Session,
     Ok(files_linked > 0 || files_copied == 0)
 }
 
-/// Generate unique directory path of the form:
+/// Generates unique directory path of the form:
 /// {crate_dir}/s-{timestamp}-{random-number}-working
 fn generate_session_dir_path(crate_dir: &Path) -> PathBuf {
     let timestamp = timestamp_to_string(SystemTime::now());
@@ -509,7 +509,7 @@ fn delete_session_dir_lock_file(sess: &Session,
     }
 }
 
-/// Find the most recent published session directory that is not in the
+/// Finds the most recent published session directory that is not in the
 /// ignore-list.
 fn find_source_directory(crate_dir: &Path,
                          source_directories_already_tried: &FxHashSet<PathBuf>)
diff --git a/src/librustc_incremental/persist/load.rs b/src/librustc_incremental/persist/load.rs
index f330de7191865..ecf8bc4a88084 100644
--- a/src/librustc_incremental/persist/load.rs
+++ b/src/librustc_incremental/persist/load.rs
@@ -9,7 +9,6 @@ use rustc::util::common::time_ext;
 use rustc_serialize::Decodable as RustcDecodable;
 use rustc_serialize::opaque::Decoder;
 use std::path::Path;
-use std;
 
 use super::data::*;
 use super::fs::*;
diff --git a/src/librustc_incremental/persist/mod.rs b/src/librustc_incremental/persist/mod.rs
index bd59f24d04e79..3aad4f5abb884 100644
--- a/src/librustc_incremental/persist/mod.rs
+++ b/src/librustc_incremental/persist/mod.rs
@@ -10,16 +10,16 @@ mod save;
 mod work_product;
 mod file_format;
 
-pub use self::fs::finalize_session_directory;
-pub use self::fs::garbage_collect_session_directories;
-pub use self::fs::in_incr_comp_dir;
-pub use self::fs::in_incr_comp_dir_sess;
-pub use self::fs::prepare_session_directory;
-pub use self::load::dep_graph_tcx_init;
-pub use self::load::load_dep_graph;
-pub use self::load::load_query_result_cache;
-pub use self::load::LoadResult;
-pub use self::save::save_dep_graph;
-pub use self::save::save_work_product_index;
-pub use self::work_product::copy_cgu_workproducts_to_incr_comp_cache_dir;
-pub use self::work_product::delete_workproduct_files;
+pub use fs::finalize_session_directory;
+pub use fs::garbage_collect_session_directories;
+pub use fs::in_incr_comp_dir;
+pub use fs::in_incr_comp_dir_sess;
+pub use fs::prepare_session_directory;
+pub use load::dep_graph_tcx_init;
+pub use load::load_dep_graph;
+pub use load::load_query_result_cache;
+pub use load::LoadResult;
+pub use save::save_dep_graph;
+pub use save::save_work_product_index;
+pub use work_product::copy_cgu_workproducts_to_incr_comp_cache_dir;
+pub use work_product::delete_workproduct_files;
diff --git a/src/librustc_incremental/persist/save.rs b/src/librustc_incremental/persist/save.rs
index 6a7553b388297..34fe2f1c25d04 100644
--- a/src/librustc_incremental/persist/save.rs
+++ b/src/librustc_incremental/persist/save.rs
@@ -129,7 +129,7 @@ fn save_in<F>(sess: &Session, path_buf: PathBuf, encode: F)
     }
 }
 
-fn encode_dep_graph(tcx: TyCtxt,
+fn encode_dep_graph(tcx: TyCtxt<'_, '_, '_>,
                     encoder: &mut Encoder) {
     // First encode the commandline arguments hash
     tcx.sess.opts.dep_tracking_hash().encode(encoder).unwrap();
@@ -234,7 +234,7 @@ fn encode_work_product_index(work_products: &FxHashMap<WorkProductId, WorkProduc
     serialized_products.encode(encoder).unwrap();
 }
 
-fn encode_query_cache(tcx: TyCtxt,
+fn encode_query_cache(tcx: TyCtxt<'_, '_, '_>,
                       encoder: &mut Encoder) {
     time(tcx.sess, "serialize query result cache", || {
         tcx.serialize_query_result_cache(encoder).unwrap();
diff --git a/src/librustc_incremental/persist/work_product.rs b/src/librustc_incremental/persist/work_product.rs
index 535f6930aa39a..3495b27c5ebca 100644
--- a/src/librustc_incremental/persist/work_product.rs
+++ b/src/librustc_incremental/persist/work_product.rs
@@ -1,6 +1,6 @@
 //! This module contains files for saving intermediate work-products.
 
-use persist::fs::*;
+use crate::persist::fs::*;
 use rustc::dep_graph::{WorkProduct, WorkProductId, WorkProductFileKind};
 use rustc::session::Session;
 use rustc_fs_util::link_or_copy;
diff --git a/src/librustc_lint/Cargo.toml b/src/librustc_lint/Cargo.toml
index 7fb7a06ea1ad5..fd2b635faefb4 100644
--- a/src/librustc_lint/Cargo.toml
+++ b/src/librustc_lint/Cargo.toml
@@ -2,12 +2,12 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_lint"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_lint"
 path = "lib.rs"
 crate-type = ["dylib"]
-test = false
 
 [dependencies]
 log = "0.4"
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index f895542e43ada..925cde5b5cc8b 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -13,14 +13,18 @@
 //! `LintPass` (also, note that such lints will need to be defined in
 //! `rustc::lint::builtin`, not here).
 //!
-//! If you define a new `LintPass`, you will also need to add it to the
-//! `add_builtin!` or `add_builtin_with_new!` invocation in `lib.rs`.
-//! Use the former for unit-like structs and the latter for structs with
-//! a `pub fn new()`.
+//! If you define a new `EarlyLintPass`, you will also need to add it to the
+//! `add_early_builtin!` or `add_early_builtin_with_new!` invocation in
+//! `lib.rs`. Use the former for unit-like structs and the latter for structs
+//! with a `pub fn new()`.
+//!
+//! If you define a new `LateLintPass`, you will also need to add it to the
+//! `late_lint_methods!` invocation in `lib.rs`.
 
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::ty::{self, Ty};
+use rustc::{lint, util};
 use hir::Node;
 use util::nodemap::NodeSet;
 use lint::{LateContext, LintContext, LintArray};
@@ -42,10 +46,13 @@ use syntax::symbol::keywords;
 use syntax::errors::{Applicability, DiagnosticBuilder};
 use syntax::print::pprust::expr_to_string;
 use syntax::visit::FnKind;
+use syntax::struct_span_err;
 
 use rustc::hir::{self, GenericParamKind, PatKind};
 
-use nonstandard_style::{MethodLateContext, method_context};
+use crate::nonstandard_style::{MethodLateContext, method_context};
+
+use log::debug;
 
 // hardwired lints from librustc
 pub use lint::builtin::*;
@@ -60,13 +67,17 @@ declare_lint! {
 pub struct WhileTrue;
 
 impl LintPass for WhileTrue {
+    fn name(&self) -> &'static str {
+        "WhileTrue"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(WHILE_TRUE)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for WhileTrue {
-    fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, e: &hir::Expr) {
         if let hir::ExprKind::While(ref cond, ..) = e.node {
             if let hir::ExprKind::Lit(ref lit) = cond.node {
                 if let ast::LitKind::Bool(true) = lit.node {
@@ -74,7 +85,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for WhileTrue {
                         let msg = "denote infinite loops with `loop { ... }`";
                         let condition_span = cx.tcx.sess.source_map().def_span(e.span);
                         let mut err = cx.struct_span_lint(WHILE_TRUE, condition_span, msg);
-                        err.span_suggestion_short_with_applicability(
+                        err.span_suggestion_short(
                             condition_span,
                             "use `loop`",
                             "loop".to_owned(),
@@ -98,7 +109,7 @@ declare_lint! {
 pub struct BoxPointers;
 
 impl BoxPointers {
-    fn check_heap_type<'a, 'tcx>(&self, cx: &LateContext, span: Span, ty: Ty) {
+    fn check_heap_type<'a, 'tcx>(&self, cx: &LateContext<'_, '_>, span: Span, ty: Ty<'_>) {
         for leaf_ty in ty.walk() {
             if leaf_ty.is_box() {
                 let m = format!("type uses owned (Box type) pointers: {}", ty);
@@ -109,13 +120,17 @@ impl BoxPointers {
 }
 
 impl LintPass for BoxPointers {
+    fn name(&self) -> &'static str {
+        "BoxPointers"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(BOX_POINTERS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxPointers {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         match it.node {
             hir::ItemKind::Fn(..) |
             hir::ItemKind::Ty(..) |
@@ -142,8 +157,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxPointers {
         }
     }
 
-    fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
-        let ty = cx.tables.node_id_to_type(e.hir_id);
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, e: &hir::Expr) {
+        let ty = cx.tables.node_type(e.hir_id);
         self.check_heap_type(cx, e.span, ty);
     }
 }
@@ -158,13 +173,17 @@ declare_lint! {
 pub struct NonShorthandFieldPatterns;
 
 impl LintPass for NonShorthandFieldPatterns {
+    fn name(&self) -> &'static str {
+        "NonShorthandFieldPatterns"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(NON_SHORTHAND_FIELD_PATTERNS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonShorthandFieldPatterns {
-    fn check_pat(&mut self, cx: &LateContext, pat: &hir::Pat) {
+    fn check_pat(&mut self, cx: &LateContext<'_, '_>, pat: &hir::Pat) {
         if let PatKind::Struct(ref qpath, ref field_pats, _) = pat.node {
             let variant = cx.tables.pat_ty(pat).ty_adt_def()
                                    .expect("struct pattern type is not an ADT")
@@ -179,7 +198,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonShorthandFieldPatterns {
                     // (Issue #49588)
                     continue;
                 }
-                if let PatKind::Binding(_, _, ident, None) = fieldpat.node.pat.node {
+                if let PatKind::Binding(_, _, _, ident, None) = fieldpat.node.pat.node {
                     if cx.tcx.find_field_index(ident, &variant) ==
                        Some(cx.tcx.field_index(fieldpat.node.id, cx.tables)) {
                         let mut err = cx.struct_span_lint(NON_SHORTHAND_FIELD_PATTERNS,
@@ -187,7 +206,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonShorthandFieldPatterns {
                                      &format!("the `{}:` in this pattern is redundant", ident));
                         let subspan = cx.tcx.sess.source_map().span_through_char(fieldpat.span,
                                                                                  ':');
-                        err.span_suggestion_short_with_applicability(
+                        err.span_suggestion_short(
                             subspan,
                             "remove this",
                             ident.to_string(),
@@ -211,13 +230,17 @@ declare_lint! {
 pub struct UnsafeCode;
 
 impl LintPass for UnsafeCode {
+    fn name(&self) -> &'static str {
+        "UnsafeCode"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNSAFE_CODE)
     }
 }
 
 impl UnsafeCode {
-    fn report_unsafe(&self, cx: &EarlyContext, span: Span, desc: &'static str) {
+    fn report_unsafe(&self, cx: &EarlyContext<'_>, span: Span, desc: &'static str) {
         // This comes from a macro that has #[allow_internal_unsafe].
         if span.allows_unsafe() {
             return;
@@ -228,7 +251,7 @@ impl UnsafeCode {
 }
 
 impl EarlyLintPass for UnsafeCode {
-    fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) {
+    fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
         if attr.check_name("allow_internal_unsafe") {
             self.report_unsafe(cx, attr.span, "`allow_internal_unsafe` allows defining \
                                                macros using unsafe without triggering \
@@ -236,7 +259,7 @@ impl EarlyLintPass for UnsafeCode {
         }
     }
 
-    fn check_expr(&mut self, cx: &EarlyContext, e: &ast::Expr) {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
         if let ast::ExprKind::Block(ref blk, _) = e.node {
             // Don't warn about generated blocks, that'll just pollute the output.
             if blk.rules == ast::BlockCheckMode::Unsafe(ast::UserProvided) {
@@ -245,7 +268,7 @@ impl EarlyLintPass for UnsafeCode {
         }
     }
 
-    fn check_item(&mut self, cx: &EarlyContext, it: &ast::Item) {
+    fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) {
         match it.node {
             ast::ItemKind::Trait(_, ast::Unsafety::Unsafe, ..) => {
                 self.report_unsafe(cx, it.span, "declaration of an `unsafe` trait")
@@ -260,8 +283,8 @@ impl EarlyLintPass for UnsafeCode {
     }
 
     fn check_fn(&mut self,
-                cx: &EarlyContext,
-                fk: FnKind,
+                cx: &EarlyContext<'_>,
+                fk: FnKind<'_>,
                 _: &ast::FnDecl,
                 span: Span,
                 _: ast::NodeId) {
@@ -280,7 +303,7 @@ impl EarlyLintPass for UnsafeCode {
         }
     }
 
-    fn check_trait_item(&mut self, cx: &EarlyContext, item: &ast::TraitItem) {
+    fn check_trait_item(&mut self, cx: &EarlyContext<'_>, item: &ast::TraitItem) {
         if let ast::TraitItemKind::Method(ref sig, None) = item.node {
             if sig.header.unsafety == ast::Unsafety::Unsafe {
                 self.report_unsafe(cx, item.span, "declaration of an `unsafe` method")
@@ -297,8 +320,7 @@ declare_lint! {
 }
 
 pub struct MissingDoc {
-    /// Stack of whether #[doc(hidden)] is set
-    /// at each level which has lint attributes.
+    /// Stack of whether `#[doc(hidden)]` is set at each level which has lint attributes.
     doc_hidden_stack: Vec<bool>,
 
     /// Private traits or trait items that leaked through. Don't check their methods.
@@ -338,7 +360,7 @@ impl MissingDoc {
     }
 
     fn check_missing_docs_attrs(&self,
-                                cx: &LateContext,
+                                cx: &LateContext<'_, '_>,
                                 id: Option<ast::NodeId>,
                                 attrs: &[ast::Attribute],
                                 sp: Span,
@@ -373,13 +395,17 @@ impl MissingDoc {
 }
 
 impl LintPass for MissingDoc {
+    fn name(&self) -> &'static str {
+        "MissingDoc"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(MISSING_DOCS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
-    fn enter_lint_attrs(&mut self, _: &LateContext, attrs: &[ast::Attribute]) {
+    fn enter_lint_attrs(&mut self, _: &LateContext<'_, '_>, attrs: &[ast::Attribute]) {
         let doc_hidden = self.doc_hidden() ||
                          attrs.iter().any(|attr| {
             attr.check_name("doc") &&
@@ -391,11 +417,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
         self.doc_hidden_stack.push(doc_hidden);
     }
 
-    fn exit_lint_attrs(&mut self, _: &LateContext, _attrs: &[ast::Attribute]) {
+    fn exit_lint_attrs(&mut self, _: &LateContext<'_, '_>, _attrs: &[ast::Attribute]) {
         self.doc_hidden_stack.pop().expect("empty doc_hidden_stack");
     }
 
-    fn check_crate(&mut self, cx: &LateContext, krate: &hir::Crate) {
+    fn check_crate(&mut self, cx: &LateContext<'_, '_>, krate: &hir::Crate) {
         self.check_missing_docs_attrs(cx, None, &krate.attrs, krate.span, "crate");
 
         for macro_def in &krate.exported_macros {
@@ -408,7 +434,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
         }
     }
 
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         let desc = match it.node {
             hir::ItemKind::Fn(..) => "a function",
             hir::ItemKind::Mod(..) => "a module",
@@ -453,7 +479,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
         self.check_missing_docs_attrs(cx, Some(it.id), &it.attrs, it.span, desc);
     }
 
-    fn check_trait_item(&mut self, cx: &LateContext, trait_item: &hir::TraitItem) {
+    fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, trait_item: &hir::TraitItem) {
         if self.private_traits.contains(&trait_item.id) {
             return;
         }
@@ -471,7 +497,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
                                       desc);
     }
 
-    fn check_impl_item(&mut self, cx: &LateContext, impl_item: &hir::ImplItem) {
+    fn check_impl_item(&mut self, cx: &LateContext<'_, '_>, impl_item: &hir::ImplItem) {
         // If the method is an impl for a trait, don't doc.
         if method_context(cx, impl_item.id) == MethodLateContext::TraitImpl {
             return;
@@ -490,7 +516,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
                                       desc);
     }
 
-    fn check_struct_field(&mut self, cx: &LateContext, sf: &hir::StructField) {
+    fn check_struct_field(&mut self, cx: &LateContext<'_, '_>, sf: &hir::StructField) {
         if !sf.is_positional() {
             self.check_missing_docs_attrs(cx,
                                           Some(sf.id),
@@ -500,7 +526,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc {
         }
     }
 
-    fn check_variant(&mut self, cx: &LateContext, v: &hir::Variant, _: &hir::Generics) {
+    fn check_variant(&mut self, cx: &LateContext<'_, '_>, v: &hir::Variant, _: &hir::Generics) {
         self.check_missing_docs_attrs(cx,
                                       Some(v.node.data.id()),
                                       &v.node.attrs,
@@ -519,13 +545,17 @@ declare_lint! {
 pub struct MissingCopyImplementations;
 
 impl LintPass for MissingCopyImplementations {
+    fn name(&self) -> &'static str {
+        "MissingCopyImplementations"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(MISSING_COPY_IMPLEMENTATIONS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingCopyImplementations {
-    fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) {
         if !cx.access_levels.is_reachable(item.id) {
             return;
         }
@@ -586,13 +616,17 @@ impl MissingDebugImplementations {
 }
 
 impl LintPass for MissingDebugImplementations {
+    fn name(&self) -> &'static str {
+        "MissingDebugImplementations"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(MISSING_DEBUG_IMPLEMENTATIONS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDebugImplementations {
-    fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) {
         if !cx.access_levels.is_reachable(item.id) {
             return;
         }
@@ -638,18 +672,22 @@ declare_lint! {
     "detects anonymous parameters"
 }
 
-/// Checks for use of anonymous parameters (RFC 1685)
-#[derive(Clone)]
+/// Checks for use of anonymous parameters (RFC 1685).
+#[derive(Copy, Clone)]
 pub struct AnonymousParameters;
 
 impl LintPass for AnonymousParameters {
+    fn name(&self) -> &'static str {
+        "AnonymousParameters"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(ANONYMOUS_PARAMETERS)
     }
 }
 
 impl EarlyLintPass for AnonymousParameters {
-    fn check_trait_item(&mut self, cx: &EarlyContext, it: &ast::TraitItem) {
+    fn check_trait_item(&mut self, cx: &EarlyContext<'_>, it: &ast::TraitItem) {
         match it.node {
             ast::TraitItemKind::Method(ref sig, _) => {
                 for arg in sig.decl.inputs.iter() {
@@ -672,7 +710,7 @@ impl EarlyLintPass for AnonymousParameters {
                                     arg.pat.span,
                                     "anonymous parameters are deprecated and will be \
                                      removed in the next edition."
-                                ).span_suggestion_with_applicability(
+                                ).span_suggestion(
                                     arg.pat.span,
                                     "Try naming the parameter or explicitly \
                                     ignoring it",
@@ -690,7 +728,7 @@ impl EarlyLintPass for AnonymousParameters {
     }
 }
 
-/// Checks for use of attributes which have been deprecated.
+/// Check for use of attributes which have been deprecated.
 #[derive(Clone)]
 pub struct DeprecatedAttr {
     // This is not free to compute, so we want to keep it around, rather than
@@ -707,13 +745,17 @@ impl DeprecatedAttr {
 }
 
 impl LintPass for DeprecatedAttr {
+    fn name(&self) -> &'static str {
+        "DeprecatedAttr"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!()
     }
 }
 
 impl EarlyLintPass for DeprecatedAttr {
-    fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) {
+    fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) {
         for &&(n, _, _, ref g) in &self.depr_attrs {
             if attr.name() == n {
                 if let &AttributeGate::Gated(Stability::Deprecated(link, suggestion),
@@ -723,7 +765,7 @@ impl EarlyLintPass for DeprecatedAttr {
                     let msg = format!("use of deprecated attribute `{}`: {}. See {}",
                                       name, reason, link);
                     let mut err = cx.struct_span_lint(DEPRECATED, attr.span, &msg);
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         attr.span,
                         suggestion.unwrap_or("remove this attribute"),
                         String::new(),
@@ -747,6 +789,10 @@ declare_lint! {
 pub struct UnusedDocComment;
 
 impl LintPass for UnusedDocComment {
+    fn name(&self) -> &'static str {
+        "UnusedDocComment"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array![UNUSED_DOC_COMMENTS]
     }
@@ -764,15 +810,15 @@ impl UnusedDocComment {
 }
 
 impl EarlyLintPass for UnusedDocComment {
-    fn check_local(&mut self, cx: &EarlyContext, decl: &ast::Local) {
+    fn check_local(&mut self, cx: &EarlyContext<'_>, decl: &ast::Local) {
         self.warn_if_doc(decl.attrs.iter(), cx);
     }
 
-    fn check_arm(&mut self, cx: &EarlyContext, arm: &ast::Arm) {
+    fn check_arm(&mut self, cx: &EarlyContext<'_>, arm: &ast::Arm) {
         self.warn_if_doc(arm.attrs.iter(), cx);
     }
 
-    fn check_expr(&mut self, cx: &EarlyContext, expr: &ast::Expr) {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
         self.warn_if_doc(expr.attrs.iter(), cx);
     }
 }
@@ -787,13 +833,17 @@ declare_lint! {
 pub struct PluginAsLibrary;
 
 impl LintPass for PluginAsLibrary {
+    fn name(&self) -> &'static str {
+        "PluginAsLibrary"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array![PLUGIN_AS_LIBRARY]
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for PluginAsLibrary {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         if cx.tcx.plugin_registrar_fn(LOCAL_CRATE).is_some() {
             // We're compiling a plugin; it's fine to link other plugins.
             return;
@@ -839,6 +889,10 @@ declare_lint! {
 pub struct InvalidNoMangleItems;
 
 impl LintPass for InvalidNoMangleItems {
+    fn name(&self) -> &'static str {
+        "InvalidNoMangleItems"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(NO_MANGLE_CONST_ITEMS,
                     NO_MANGLE_GENERIC_ITEMS)
@@ -846,19 +900,21 @@ impl LintPass for InvalidNoMangleItems {
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidNoMangleItems {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         match it.node {
             hir::ItemKind::Fn(.., ref generics, _) => {
                 if let Some(no_mangle_attr) = attr::find_by_name(&it.attrs, "no_mangle") {
                     for param in &generics.params {
                         match param.kind {
                             GenericParamKind::Lifetime { .. } => {}
-                            GenericParamKind::Type { .. } => {
-                                let mut err = cx.struct_span_lint(NO_MANGLE_GENERIC_ITEMS,
-                                                                  it.span,
-                                                                  "functions generic over \
-                                                                   types must be mangled");
-                                err.span_suggestion_short_with_applicability(
+                            GenericParamKind::Type { .. } |
+                            GenericParamKind::Const { .. } => {
+                                let mut err = cx.struct_span_lint(
+                                    NO_MANGLE_GENERIC_ITEMS,
+                                    it.span,
+                                    "functions generic over types or consts must be mangled",
+                                );
+                                err.span_suggestion_short(
                                     no_mangle_attr.span,
                                     "remove this attribute",
                                     String::new(),
@@ -886,7 +942,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidNoMangleItems {
                         .unwrap_or(0) as u32;
                     // `const` is 5 chars
                     let const_span = it.span.with_hi(BytePos(it.span.lo().0 + start + 5));
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         const_span,
                         "try a static value",
                         "pub static".to_owned(),
@@ -910,13 +966,17 @@ declare_lint! {
 }
 
 impl LintPass for MutableTransmutes {
+    fn name(&self) -> &'static str {
+        "MutableTransmutes"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(MUTABLE_TRANSMUTES)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes {
-    fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &hir::Expr) {
         use rustc_target::spec::abi::Abi::RustIntrinsic;
 
         let msg = "mutating transmuted &mut T from &T may cause undefined behavior, \
@@ -944,7 +1004,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes {
                 if !def_id_is_transmute(cx, did) {
                     return None;
                 }
-                let sig = cx.tables.node_id_to_type(expr.hir_id).fn_sig(cx.tcx);
+                let sig = cx.tables.node_type(expr.hir_id).fn_sig(cx.tcx);
                 let from = sig.inputs().skip_binder()[0];
                 let to = *sig.output().skip_binder();
                 return Some((&from.sty, &to.sty));
@@ -952,7 +1012,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes {
             None
         }
 
-        fn def_id_is_transmute(cx: &LateContext, def_id: DefId) -> bool {
+        fn def_id_is_transmute(cx: &LateContext<'_, '_>, def_id: DefId) -> bool {
             cx.tcx.fn_sig(def_id).abi() == RustIntrinsic &&
             cx.tcx.item_name(def_id) == "transmute"
         }
@@ -970,13 +1030,17 @@ declare_lint! {
 }
 
 impl LintPass for UnstableFeatures {
+    fn name(&self) -> &'static str {
+        "UnstableFeatures"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNSTABLE_FEATURES)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnstableFeatures {
-    fn check_attribute(&mut self, ctx: &LateContext, attr: &ast::Attribute) {
+    fn check_attribute(&mut self, ctx: &LateContext<'_, '_>, attr: &ast::Attribute) {
         if attr.check_name("feature") {
             if let Some(items) = attr.meta_item_list() {
                 for item in items {
@@ -997,13 +1061,17 @@ declare_lint! {
 }
 
 impl LintPass for UnionsWithDropFields {
+    fn name(&self) -> &'static str {
+        "UnionsWithDropFields"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNIONS_WITH_DROP_FIELDS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnionsWithDropFields {
-    fn check_item(&mut self, ctx: &LateContext, item: &hir::Item) {
+    fn check_item(&mut self, ctx: &LateContext<'_, '_>, item: &hir::Item) {
         if let hir::ItemKind::Union(ref vdata, _) = item.node {
             for field in vdata.fields() {
                 let field_ty = ctx.tcx.type_of(ctx.tcx.hir().local_def_id(field.id));
@@ -1019,7 +1087,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnionsWithDropFields {
     }
 }
 
-/// Lint for items marked `pub` that aren't reachable from other crates
+/// Lint for items marked `pub` that aren't reachable from other crates.
+#[derive(Copy, Clone)]
 pub struct UnreachablePub;
 
 declare_lint! {
@@ -1029,13 +1098,17 @@ declare_lint! {
 }
 
 impl LintPass for UnreachablePub {
+    fn name(&self) -> &'static str {
+        "UnreachablePub"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNREACHABLE_PUB)
     }
 }
 
 impl UnreachablePub {
-    fn perform_lint(&self, cx: &LateContext, what: &str, id: ast::NodeId,
+    fn perform_lint(&self, cx: &LateContext<'_, '_>, what: &str, id: ast::NodeId,
                     vis: &hir::Visibility, span: Span, exportable: bool) {
         let mut applicability = Applicability::MachineApplicable;
         match vis.node {
@@ -1052,10 +1125,12 @@ impl UnreachablePub {
                     "pub(crate)"
                 }.to_owned();
 
-                err.span_suggestion_with_applicability(vis.span,
-                                                       "consider restricting its visibility",
-                                                       replacement,
-                                                       applicability);
+                err.span_suggestion(
+                    vis.span,
+                    "consider restricting its visibility",
+                    replacement,
+                    applicability,
+                );
                 if exportable {
                     err.help("or consider exporting it for use by other crates");
                 }
@@ -1068,25 +1143,25 @@ impl UnreachablePub {
 
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnreachablePub {
-    fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) {
         self.perform_lint(cx, "item", item.id, &item.vis, item.span, true);
     }
 
-    fn check_foreign_item(&mut self, cx: &LateContext, foreign_item: &hir::ForeignItem) {
+    fn check_foreign_item(&mut self, cx: &LateContext<'_, '_>, foreign_item: &hir::ForeignItem) {
         self.perform_lint(cx, "item", foreign_item.id, &foreign_item.vis,
                           foreign_item.span, true);
     }
 
-    fn check_struct_field(&mut self, cx: &LateContext, field: &hir::StructField) {
+    fn check_struct_field(&mut self, cx: &LateContext<'_, '_>, field: &hir::StructField) {
         self.perform_lint(cx, "field", field.id, &field.vis, field.span, false);
     }
 
-    fn check_impl_item(&mut self, cx: &LateContext, impl_item: &hir::ImplItem) {
+    fn check_impl_item(&mut self, cx: &LateContext<'_, '_>, impl_item: &hir::ImplItem) {
         self.perform_lint(cx, "item", impl_item.id, &impl_item.vis, impl_item.span, false);
     }
 }
 
-/// Lint for trait and lifetime bounds in type aliases being mostly ignored:
+/// Lint for trait and lifetime bounds in type aliases being mostly ignored.
 /// They are relevant when using associated types, but otherwise neither checked
 /// at definition site nor enforced at use site.
 
@@ -1099,6 +1174,10 @@ declare_lint! {
 }
 
 impl LintPass for TypeAliasBounds {
+    fn name(&self) -> &'static str {
+        "TypeAliasBounds"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TYPE_ALIAS_BOUNDS)
     }
@@ -1123,7 +1202,7 @@ impl TypeAliasBounds {
         }
     }
 
-    fn suggest_changing_assoc_types(ty: &hir::Ty, err: &mut DiagnosticBuilder) {
+    fn suggest_changing_assoc_types(ty: &hir::Ty, err: &mut DiagnosticBuilder<'_>) {
         // Access to associates types should use `<T as Bound>::Assoc`, which does not need a
         // bound.  Let's see if this type does that.
 
@@ -1155,7 +1234,7 @@ impl TypeAliasBounds {
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds {
-    fn check_item(&mut self, cx: &LateContext, item: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) {
         let (ty, type_alias_generics) = match item.node {
             hir::ItemKind::Ty(ref ty, ref generics) => (&*ty, generics),
             _ => return,
@@ -1203,11 +1282,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds {
 pub struct UnusedBrokenConst;
 
 impl LintPass for UnusedBrokenConst {
+    fn name(&self) -> &'static str {
+        "UnusedBrokenConst"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!()
     }
 }
-fn check_const(cx: &LateContext, body_id: hir::BodyId) {
+fn check_const(cx: &LateContext<'_, '_>, body_id: hir::BodyId) {
     let def_id = cx.tcx.hir().body_owner_def_id(body_id);
     let is_static = cx.tcx.is_static(def_id).is_some();
     let param_env = if is_static {
@@ -1225,7 +1308,7 @@ fn check_const(cx: &LateContext, body_id: hir::BodyId) {
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedBrokenConst {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         match it.node {
             hir::ItemKind::Const(_, body_id) => {
                 check_const(cx, body_id);
@@ -1249,6 +1332,10 @@ declare_lint! {
 }
 
 impl LintPass for TrivialConstraints {
+    fn name(&self) -> &'static str {
+        "TrivialConstraints"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TRIVIAL_BOUNDS)
     }
@@ -1303,6 +1390,10 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TrivialConstraints {
 pub struct SoftLints;
 
 impl LintPass for SoftLints {
+    fn name(&self) -> &'static str {
+        "SoftLints"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(
             WHILE_TRUE,
@@ -1337,13 +1428,17 @@ declare_lint! {
 pub struct EllipsisInclusiveRangePatterns;
 
 impl LintPass for EllipsisInclusiveRangePatterns {
+    fn name(&self) -> &'static str {
+        "EllipsisInclusiveRangePatterns"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS)
     }
 }
 
 impl EarlyLintPass for EllipsisInclusiveRangePatterns {
-    fn check_pat(&mut self, cx: &EarlyContext, pat: &ast::Pat, visit_subpats: &mut bool) {
+    fn check_pat(&mut self, cx: &EarlyContext<'_>, pat: &ast::Pat, visit_subpats: &mut bool) {
         use self::ast::{PatKind, RangeEnd, RangeSyntax::DotDotDot};
 
         /// If `pat` is a `...` pattern, return the start and end of the range, as well as the span
@@ -1368,7 +1463,7 @@ impl EarlyLintPass for EllipsisInclusiveRangePatterns {
             if parenthesise {
                 *visit_subpats = false;
                 let mut err = cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, pat.span, msg);
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     pat.span,
                     suggestion,
                     format!("&({}..={})", expr_to_string(&start), expr_to_string(&end)),
@@ -1377,7 +1472,7 @@ impl EarlyLintPass for EllipsisInclusiveRangePatterns {
                 err.emit();
             } else {
                 let mut err = cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, join, msg);
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     join,
                     suggestion,
                     "..=".to_owned(),
@@ -1411,13 +1506,17 @@ impl UnnameableTestItems {
 }
 
 impl LintPass for UnnameableTestItems {
+    fn name(&self) -> &'static str {
+        "UnnameableTestItems"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNNAMEABLE_TEST_ITEMS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnnameableTestItems {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         if self.items_nameable {
             if let hir::ItemKind::Mod(..) = it.node {}
             else {
@@ -1436,7 +1535,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnnameableTestItems {
         }
     }
 
-    fn check_item_post(&mut self, _cx: &LateContext, it: &hir::Item) {
+    fn check_item_post(&mut self, _cx: &LateContext<'_, '_>, it: &hir::Item) {
         if !self.items_nameable && self.boundary == it.id {
             self.items_nameable = true;
         }
@@ -1449,18 +1548,22 @@ declare_lint! {
     "detects edition keywords being used as an identifier"
 }
 
-/// Checks for uses of edition keywords used as an identifier
-#[derive(Clone)]
+/// Check for uses of edition keywords used as an identifier.
+#[derive(Copy, Clone)]
 pub struct KeywordIdents;
 
 impl LintPass for KeywordIdents {
+    fn name(&self) -> &'static str {
+        "KeywordIdents"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(KEYWORD_IDENTS)
     }
 }
 
 impl KeywordIdents {
-    fn check_tokens(&mut self, cx: &EarlyContext, tokens: TokenStream) {
+    fn check_tokens(&mut self, cx: &EarlyContext<'_>, tokens: TokenStream) {
         for tt in tokens.into_trees() {
             match tt {
                 TokenTree::Token(span, tok) => match tok.ident() {
@@ -1474,7 +1577,7 @@ impl KeywordIdents {
                     _ => {},
                 }
                 TokenTree::Delimited(_, _, tts) => {
-                    self.check_tokens(cx, tts.stream())
+                    self.check_tokens(cx, tts)
                 },
             }
         }
@@ -1482,13 +1585,13 @@ impl KeywordIdents {
 }
 
 impl EarlyLintPass for KeywordIdents {
-    fn check_mac_def(&mut self, cx: &EarlyContext, mac_def: &ast::MacroDef, _id: ast::NodeId) {
+    fn check_mac_def(&mut self, cx: &EarlyContext<'_>, mac_def: &ast::MacroDef, _id: ast::NodeId) {
         self.check_tokens(cx, mac_def.stream());
     }
-    fn check_mac(&mut self, cx: &EarlyContext, mac: &ast::Mac) {
+    fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &ast::Mac) {
         self.check_tokens(cx, mac.node.tts.clone().into());
     }
-    fn check_ident(&mut self, cx: &EarlyContext, ident: ast::Ident) {
+    fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: ast::Ident) {
         let ident_str = &ident.as_str()[..];
         let cur_edition = cx.sess.edition();
         let is_raw_ident = |ident: ast::Ident| {
@@ -1521,7 +1624,7 @@ impl EarlyLintPass for KeywordIdents {
                         E0721,
                         "`await` is a keyword in the {} edition", cur_edition,
                     );
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         ident.span,
                         "you can use a raw identifier to stay compatible",
                         "r#await".to_string(),
@@ -1545,7 +1648,7 @@ impl EarlyLintPass for KeywordIdents {
                      ident.as_str(),
                      next_edition),
         );
-        lint.span_suggestion_with_applicability(
+        lint.span_suggestion(
             ident.span,
             "you can use a raw identifier to stay compatible",
             format!("r#{}", ident.as_str()),
@@ -1559,6 +1662,10 @@ impl EarlyLintPass for KeywordIdents {
 pub struct ExplicitOutlivesRequirements;
 
 impl LintPass for ExplicitOutlivesRequirements {
+    fn name(&self) -> &'static str {
+        "ExplicitOutlivesRequirements"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array![EXPLICIT_OUTLIVES_REQUIREMENTS]
     }
@@ -1567,7 +1674,7 @@ impl LintPass for ExplicitOutlivesRequirements {
 impl ExplicitOutlivesRequirements {
     fn collect_outlives_bound_spans(
         &self,
-        cx: &LateContext,
+        cx: &LateContext<'_, '_>,
         item_def_id: DefId,
         param_name: &str,
         bounds: &hir::GenericBounds,
@@ -1686,14 +1793,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ExplicitOutlivesRequirements {
 
             for param in &generics.params {
                 let param_name = match param.kind {
-                    hir::GenericParamKind::Lifetime { .. } => { continue; },
+                    hir::GenericParamKind::Lifetime { .. } => continue,
                     hir::GenericParamKind::Type { .. } => {
                         match param.name {
-                            hir::ParamName::Fresh(_) => { continue; },
-                            hir::ParamName::Error => { continue; },
-                            hir::ParamName::Plain(name) => name.to_string()
+                            hir::ParamName::Fresh(_) => continue,
+                            hir::ParamName::Error => continue,
+                            hir::ParamName::Plain(name) => name.to_string(),
                         }
                     }
+                    hir::GenericParamKind::Const { .. } => continue,
                 };
                 let bound_spans = self.collect_outlives_bound_spans(
                     cx, def_id, &param_name, &param.bounds, infer_static
@@ -1769,7 +1877,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ExplicitOutlivesRequirements {
                     lint_spans.clone(),
                     "outlives requirements can be inferred"
                 );
-                err.multipart_suggestion_with_applicability(
+                err.multipart_suggestion(
                     if bound_count == 1 {
                         "remove this bound"
                     } else {
diff --git a/src/librustc_lint/diagnostics.rs b/src/librustc_lint/diagnostics.rs
index 9a608e4fef08b..3165673111cca 100644
--- a/src/librustc_lint/diagnostics.rs
+++ b/src/librustc_lint/diagnostics.rs
@@ -1,3 +1,5 @@
+use syntax::{register_diagnostic, register_diagnostics};
+
 register_diagnostics! {
     E0721, // `await` keyword
 }
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index 2d764d11c66aa..5c243e1389073 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -9,28 +9,20 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![cfg_attr(test, feature(test))]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(nll)]
-#![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 
 #![recursion_limit="256"]
 
-#[macro_use]
-extern crate syntax;
+#![deny(rust_2018_idioms)]
+
 #[macro_use]
 extern crate rustc;
-#[macro_use]
-extern crate log;
-extern crate rustc_target;
-extern crate syntax_pos;
-extern crate rustc_data_structures;
 
 mod diagnostics;
 mod nonstandard_style;
@@ -39,7 +31,7 @@ mod types;
 mod unused;
 
 use rustc::lint;
-use rustc::lint::{LateContext, LateLintPass, LintPass, LintArray};
+use rustc::lint::{EarlyContext, LateContext, LateLintPass, EarlyLintPass, LintPass, LintArray};
 use rustc::lint::builtin::{
     BARE_TRAIT_OBJECTS,
     ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
@@ -52,7 +44,6 @@ use rustc::lint::builtin::{
     parser::ILL_FORMED_ATTRIBUTE_INPUT,
 };
 use rustc::session;
-use rustc::util;
 use rustc::hir;
 
 use syntax::ast;
@@ -71,57 +62,68 @@ use unused::*;
 /// Useful for other parts of the compiler.
 pub use builtin::SoftLints;
 
+macro_rules! pre_expansion_lint_passes {
+    ($macro:path, $args:tt) => (
+        $macro!($args, [
+            KeywordIdents: KeywordIdents,
+        ]);
+    )
+}
+
+macro_rules! early_lint_passes {
+    ($macro:path, $args:tt) => (
+        $macro!($args, [
+            UnusedParens: UnusedParens,
+            UnusedImportBraces: UnusedImportBraces,
+            UnsafeCode: UnsafeCode,
+            AnonymousParameters: AnonymousParameters,
+            UnusedDocComment: UnusedDocComment,
+            EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns,
+            NonCamelCaseTypes: NonCamelCaseTypes,
+            DeprecatedAttr: DeprecatedAttr::new(),
+        ]);
+    )
+}
+
+macro_rules! declare_combined_early_pass {
+    ([$name:ident], $passes:tt) => (
+        early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
+    )
+}
+
+pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
+early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
+
 /// Tell the `LintStore` about all the built-in lints (the ones
 /// defined in this crate and the ones defined in
 /// `rustc::lint::builtin`).
 pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
-    macro_rules! add_early_builtin {
-        ($sess:ident, $($name:ident),*,) => (
-            {$(
-                store.register_early_pass($sess, false, box $name);
-            )*}
-        )
-    }
-
-    macro_rules! add_pre_expansion_builtin {
-        ($sess:ident, $($name:ident),*,) => (
-            {$(
-                store.register_pre_expansion_pass($sess, box $name);
-            )*}
-        )
-    }
-
-    macro_rules! add_early_builtin_with_new {
-        ($sess:ident, $($name:ident),*,) => (
-            {$(
-                store.register_early_pass($sess, false, box $name::new());
-            )*}
-        )
-    }
-
     macro_rules! add_lint_group {
         ($sess:ident, $name:expr, $($lint:ident),*) => (
             store.register_group($sess, false, $name, None, vec![$(LintId::of($lint)),*]);
         )
     }
 
-    add_pre_expansion_builtin!(sess,
-        KeywordIdents,
-    );
-
-    add_early_builtin!(sess,
-                       UnusedParens,
-                       UnusedImportBraces,
-                       UnsafeCode,
-                       AnonymousParameters,
-                       UnusedDocComment,
-                       EllipsisInclusiveRangePatterns,
-                       NonCamelCaseTypes,
-                       );
+    macro_rules! register_passes {
+        ([$method:ident], [$($passes:ident: $constructor:expr,)*]) => (
+            $(
+                store.$method(sess, false, false, box $constructor);
+            )*
+        )
+    }
 
-    add_early_builtin_with_new!(sess,
-                                DeprecatedAttr,
-                                );
+    if sess.map(|sess| sess.opts.debugging_opts.no_interleave_lints).unwrap_or(false) {
+        pre_expansion_lint_passes!(register_passes, [register_pre_expansion_pass]);
+        early_lint_passes!(register_passes, [register_early_pass]);
+    } else {
+        store.register_pre_expansion_pass(
+            sess,
+            false,
+            true,
+            box BuiltinCombinedPreExpansionLintPass::new()
+        );
+        store.register_early_pass(sess, false, true, box BuiltinCombinedEarlyLintPass::new());
+    }
 
     late_lint_methods!(declare_combined_late_lint_pass, [BuiltinCombinedLateLintPass, [
         HardwiredLints: HardwiredLints,
@@ -341,6 +343,16 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             reference: "issue #57571 <https://github.com/rust-lang/rust/issues/57571>",
             edition: None,
         },
+        FutureIncompatibleInfo {
+            id: LintId::of(AMBIGUOUS_ASSOCIATED_ITEMS),
+            reference: "issue #57644 <https://github.com/rust-lang/rust/issues/57644>",
+            edition: None,
+        },
+        FutureIncompatibleInfo {
+            id: LintId::of(DUPLICATE_MATCHER_BINDING_NAME),
+            reference: "issue #57593 <https://github.com/rust-lang/rust/issues/57593>",
+            edition: None,
+        },
         ]);
 
     // Register renamed and removed lints.
diff --git a/src/librustc_lint/nonstandard_style.rs b/src/librustc_lint/nonstandard_style.rs
index a4a3fa552e988..7c66289703ac8 100644
--- a/src/librustc_lint/nonstandard_style.rs
+++ b/src/librustc_lint/nonstandard_style.rs
@@ -1,6 +1,7 @@
 use rustc::hir::{self, GenericParamKind, PatKind};
 use rustc::hir::def::Def;
 use rustc::hir::intravisit::FnKind;
+use rustc::lint;
 use rustc::ty;
 use rustc_target::spec::abi::Abi;
 use lint::{EarlyContext, LateContext, LintContext, LintArray};
@@ -17,7 +18,7 @@ pub enum MethodLateContext {
     PlainImpl,
 }
 
-pub fn method_context(cx: &LateContext, id: ast::NodeId) -> MethodLateContext {
+pub fn method_context(cx: &LateContext<'_, '_>, id: ast::NodeId) -> MethodLateContext {
     let def_id = cx.tcx.hir().local_def_id(id);
     let item = cx.tcx.associated_item(def_id);
     match item.container {
@@ -37,66 +38,87 @@ declare_lint! {
     "types, variants, traits and type parameters should have camel case names"
 }
 
-#[derive(Copy, Clone)]
-pub struct NonCamelCaseTypes;
+fn char_has_case(c: char) -> bool {
+    c.is_lowercase() || c.is_uppercase()
+}
 
-impl NonCamelCaseTypes {
-    fn check_case(&self, cx: &EarlyContext, sort: &str, ident: &Ident) {
-        fn char_has_case(c: char) -> bool {
-            c.is_lowercase() || c.is_uppercase()
-        }
+fn is_camel_case(name: &str) -> bool {
+    let name = name.trim_matches('_');
+    if name.is_empty() {
+        return true;
+    }
 
-        fn is_camel_case(name: &str) -> bool {
-            let name = name.trim_matches('_');
-            if name.is_empty() {
-                return true;
+    // start with a non-lowercase letter rather than non-uppercase
+    // ones (some scripts don't have a concept of upper/lowercase)
+    !name.chars().next().unwrap().is_lowercase()
+        && !name.contains("__")
+        && !name.chars().collect::<Vec<_>>().windows(2).any(|pair| {
+            // contains a capitalisable character followed by, or preceded by, an underscore
+            char_has_case(pair[0]) && pair[1] == '_' || char_has_case(pair[1]) && pair[0] == '_'
+        })
+}
+
+fn to_camel_case(s: &str) -> String {
+    s.trim_matches('_')
+        .split('_')
+        .filter(|component| !component.is_empty())
+        .map(|component| {
+            let mut camel_cased_component = String::new();
+
+            let mut new_word = true;
+            let mut prev_is_lower_case = true;
+
+            for c in component.chars() {
+                // Preserve the case if an uppercase letter follows a lowercase letter, so that
+                // `camelCase` is converted to `CamelCase`.
+                if prev_is_lower_case && c.is_uppercase() {
+                    new_word = true;
+                }
+
+                if new_word {
+                    camel_cased_component.push_str(&c.to_uppercase().to_string());
+                } else {
+                    camel_cased_component.push_str(&c.to_lowercase().to_string());
+                }
+
+                prev_is_lower_case = c.is_lowercase();
+                new_word = false;
             }
 
-            // start with a non-lowercase letter rather than non-uppercase
-            // ones (some scripts don't have a concept of upper/lowercase)
-            !name.is_empty() && !name.chars().next().unwrap().is_lowercase() &&
-                !name.contains("__") && !name.chars().collect::<Vec<_>>().windows(2).any(|pair| {
-                    // contains a capitalisable character followed by, or preceded by, an underscore
-                    char_has_case(pair[0]) && pair[1] == '_' ||
-                    char_has_case(pair[1]) && pair[0] == '_'
-                })
-        }
+            camel_cased_component
+        })
+        .fold(
+            (String::new(), None),
+            |(acc, prev): (String, Option<String>), next| {
+                // separate two components with an underscore if their boundary cannot
+                // be distinguished using a uppercase/lowercase case distinction
+                let join = if let Some(prev) = prev {
+                    let l = prev.chars().last().unwrap();
+                    let f = next.chars().next().unwrap();
+                    !char_has_case(l) && !char_has_case(f)
+                } else {
+                    false
+                };
+                (acc + if join { "_" } else { "" } + &next, Some(next))
+            },
+        )
+        .0
+}
 
-        fn to_camel_case(s: &str) -> String {
-            s.trim_matches('_')
-                .split('_')
-                .map(|word| {
-                    word.chars().enumerate().map(|(i, c)| if i == 0 {
-                        c.to_uppercase().collect::<String>()
-                    } else {
-                        c.to_lowercase().collect()
-                    })
-                    .collect::<String>()
-                })
-                .filter(|x| !x.is_empty())
-                .fold((String::new(), None), |(acc, prev): (String, Option<String>), next| {
-                    // separate two components with an underscore if their boundary cannot
-                    // be distinguished using a uppercase/lowercase case distinction
-                    let join = if let Some(prev) = prev {
-                                    let l = prev.chars().last().unwrap();
-                                    let f = next.chars().next().unwrap();
-                                    !char_has_case(l) && !char_has_case(f)
-                                } else { false };
-                    (acc + if join { "_" } else { "" } + &next, Some(next))
-                }).0
-        }
+#[derive(Copy, Clone)]
+pub struct NonCamelCaseTypes;
 
+impl NonCamelCaseTypes {
+    fn check_case(&self, cx: &EarlyContext<'_>, sort: &str, ident: &Ident) {
         let name = &ident.name.as_str();
 
         if !is_camel_case(name) {
-            let c = to_camel_case(name);
-
-            let msg = format!("{} `{}` should have a camel case name", sort, name);
+            let msg = format!("{} `{}` should have an upper camel case name", sort, name);
             cx.struct_span_lint(NON_CAMEL_CASE_TYPES, ident.span, &msg)
-                .span_suggestion_with_applicability(
+                .span_suggestion(
                     ident.span,
-                    "convert the identifier to camel case",
-                    c,
+                    "convert the identifier to upper camel case",
+                    to_camel_case(name),
                     Applicability::MaybeIncorrect,
                 )
                 .emit();
@@ -105,20 +127,20 @@ impl NonCamelCaseTypes {
 }
 
 impl LintPass for NonCamelCaseTypes {
+    fn name(&self) -> &'static str {
+        "NonCamelCaseTypes"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(NON_CAMEL_CASE_TYPES)
     }
 }
 
 impl EarlyLintPass for NonCamelCaseTypes {
-    fn check_item(&mut self, cx: &EarlyContext, it: &ast::Item) {
+    fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) {
         let has_repr_c = it.attrs
             .iter()
-            .any(|attr| {
-                attr::find_repr_attrs(&cx.sess.parse_sess, attr)
-                    .iter()
-                    .any(|r| r == &attr::ReprC)
-            });
+            .any(|attr| attr::find_repr_attrs(&cx.sess.parse_sess, attr).contains(&attr::ReprC));
 
         if has_repr_c {
             return;
@@ -134,11 +156,11 @@ impl EarlyLintPass for NonCamelCaseTypes {
         }
     }
 
-    fn check_variant(&mut self, cx: &EarlyContext, v: &ast::Variant, _: &ast::Generics) {
+    fn check_variant(&mut self, cx: &EarlyContext<'_>, v: &ast::Variant, _: &ast::Generics) {
         self.check_case(cx, "variant", &v.node.ident);
     }
 
-    fn check_generic_param(&mut self, cx: &EarlyContext, param: &ast::GenericParam) {
+    fn check_generic_param(&mut self, cx: &EarlyContext<'_>, param: &ast::GenericParam) {
         if let ast::GenericParamKind::Type { .. } = param.kind {
             self.check_case(cx, "type parameter", &param.ident);
         }
@@ -186,7 +208,7 @@ impl NonSnakeCase {
     }
 
     /// Checks if a given identifier is snake case, and reports a diagnostic if not.
-    fn check_snake_case(&self, cx: &LateContext, sort: &str, ident: &Ident) {
+    fn check_snake_case(&self, cx: &LateContext<'_, '_>, sort: &str, ident: &Ident) {
         fn is_snake_case(ident: &str) -> bool {
             if ident.is_empty() {
                 return true;
@@ -219,7 +241,7 @@ impl NonSnakeCase {
             // We have a valid span in almost all cases, but we don't have one when linting a crate
             // name provided via the command line.
             if !ident.span.is_dummy() {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     ident.span,
                     "convert the identifier to snake case",
                     sc,
@@ -235,13 +257,17 @@ impl NonSnakeCase {
 }
 
 impl LintPass for NonSnakeCase {
+    fn name(&self) -> &'static str {
+        "NonSnakeCase"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(NON_SNAKE_CASE)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
-    fn check_crate(&mut self, cx: &LateContext, cr: &hir::Crate) {
+    fn check_crate(&mut self, cx: &LateContext<'_, '_>, cr: &hir::Crate) {
         let crate_ident = if let Some(name) = &cx.tcx.sess.opts.crate_name {
             Some(Ident::from_str(name))
         } else {
@@ -278,7 +304,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
         }
     }
 
-    fn check_generic_param(&mut self, cx: &LateContext, param: &hir::GenericParam) {
+    fn check_generic_param(&mut self, cx: &LateContext<'_, '_>, param: &hir::GenericParam) {
         if let GenericParamKind::Lifetime { .. } = param.kind {
             self.check_snake_case(cx, "lifetime", &param.name.ident());
         }
@@ -286,8 +312,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
 
     fn check_fn(
         &mut self,
-        cx: &LateContext,
-        fk: FnKind,
+        cx: &LateContext<'_, '_>,
+        fk: FnKind<'_>,
         _: &hir::FnDecl,
         _: &hir::Body,
         _: Span,
@@ -316,13 +342,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
         }
     }
 
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         if let hir::ItemKind::Mod(_) = it.node {
             self.check_snake_case(cx, "module", &it.ident);
         }
     }
 
-    fn check_trait_item(&mut self, cx: &LateContext, item: &hir::TraitItem) {
+    fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::TraitItem) {
         if let hir::TraitItemKind::Method(_, hir::TraitMethod::Required(pnames)) = &item.node {
             self.check_snake_case(cx, "trait method", &item.ident);
             for param_name in pnames {
@@ -331,15 +357,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonSnakeCase {
         }
     }
 
-    fn check_pat(&mut self, cx: &LateContext, p: &hir::Pat) {
-        if let &PatKind::Binding(_, _, ident, _) = &p.node {
+    fn check_pat(&mut self, cx: &LateContext<'_, '_>, p: &hir::Pat) {
+        if let &PatKind::Binding(_, _, _, ident, _) = &p.node {
             self.check_snake_case(cx, "variable", &ident);
         }
     }
 
     fn check_struct_def(
         &mut self,
-        cx: &LateContext,
+        cx: &LateContext<'_, '_>,
         s: &hir::VariantData,
         _: ast::Name,
         _: &hir::Generics,
@@ -361,7 +387,7 @@ declare_lint! {
 pub struct NonUpperCaseGlobals;
 
 impl NonUpperCaseGlobals {
-    fn check_upper_case(cx: &LateContext, sort: &str, ident: &Ident) {
+    fn check_upper_case(cx: &LateContext<'_, '_>, sort: &str, ident: &Ident) {
         let name = &ident.name.as_str();
 
         if name.chars().any(|c| c.is_lowercase()) {
@@ -369,7 +395,7 @@ impl NonUpperCaseGlobals {
 
             let msg = format!("{} `{}` should have an upper case name", sort, name);
             cx.struct_span_lint(NON_UPPER_CASE_GLOBALS, ident.span, &msg)
-                .span_suggestion_with_applicability(
+                .span_suggestion(
                     ident.span,
                     "convert the identifier to upper case",
                     uc,
@@ -381,13 +407,17 @@ impl NonUpperCaseGlobals {
 }
 
 impl LintPass for NonUpperCaseGlobals {
+    fn name(&self) -> &'static str {
+        "NonUpperCaseGlobals"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(NON_UPPER_CASE_GLOBALS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonUpperCaseGlobals {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         match it.node {
             hir::ItemKind::Static(..) if !attr::contains_name(&it.attrs, "no_mangle") => {
                 NonUpperCaseGlobals::check_upper_case(cx, "static variable", &it.ident);
@@ -399,19 +429,19 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonUpperCaseGlobals {
         }
     }
 
-    fn check_trait_item(&mut self, cx: &LateContext, ti: &hir::TraitItem) {
+    fn check_trait_item(&mut self, cx: &LateContext<'_, '_>, ti: &hir::TraitItem) {
         if let hir::TraitItemKind::Const(..) = ti.node {
             NonUpperCaseGlobals::check_upper_case(cx, "associated constant", &ti.ident);
         }
     }
 
-    fn check_impl_item(&mut self, cx: &LateContext, ii: &hir::ImplItem) {
+    fn check_impl_item(&mut self, cx: &LateContext<'_, '_>, ii: &hir::ImplItem) {
         if let hir::ImplItemKind::Const(..) = ii.node {
             NonUpperCaseGlobals::check_upper_case(cx, "associated constant", &ii.ident);
         }
     }
 
-    fn check_pat(&mut self, cx: &LateContext, p: &hir::Pat) {
+    fn check_pat(&mut self, cx: &LateContext<'_, '_>, p: &hir::Pat) {
         // Lint for constants that look like binding identifiers (#7526)
         if let PatKind::Path(hir::QPath::Resolved(None, ref path)) = p.node {
             if let Def::Const(..) = path.def {
@@ -425,4 +455,39 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonUpperCaseGlobals {
             }
         }
     }
+
+    fn check_generic_param(&mut self, cx: &LateContext<'_, '_>, param: &hir::GenericParam) {
+        if let GenericParamKind::Const { .. } = param.kind {
+            NonUpperCaseGlobals::check_upper_case(
+                cx,
+                "const parameter",
+                &param.name.ident(),
+            );
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{is_camel_case, to_camel_case};
+
+    #[test]
+    fn camel_case() {
+        assert!(!is_camel_case("userData"));
+        assert_eq!(to_camel_case("userData"), "UserData");
+
+        assert!(is_camel_case("X86_64"));
+
+        assert!(!is_camel_case("X86__64"));
+        assert_eq!(to_camel_case("X86__64"), "X86_64");
+
+        assert!(!is_camel_case("Abc_123"));
+        assert_eq!(to_camel_case("Abc_123"), "Abc123");
+
+        assert!(!is_camel_case("A1_b2_c3"));
+        assert_eq!(to_camel_case("A1_b2_c3"), "A1B2C3");
+
+        assert!(!is_camel_case("ONE_TWO_THREE"));
+        assert_eq!(to_camel_case("ONE_TWO_THREE"), "OneTwoThree");
+    }
 }
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 642681a73a8a0..34f8fc40597f1 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -4,6 +4,7 @@ use rustc::hir::Node;
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, AdtKind, ParamEnv, Ty, TyCtxt};
 use rustc::ty::layout::{self, IntegerExt, LayoutOf, VariantIdx};
+use rustc::{lint, util};
 use rustc_data_structures::indexed_vec::Idx;
 use util::nodemap::FxHashSet;
 use lint::{LateContext, LintContext, LintArray};
@@ -21,6 +22,10 @@ use syntax::source_map;
 
 use rustc::hir;
 
+use rustc::mir::interpret::{sign_extend, truncate};
+
+use log::debug;
+
 declare_lint! {
     UNUSED_COMPARISONS,
     Warn,
@@ -53,6 +58,10 @@ impl TypeLimits {
 }
 
 impl LintPass for TypeLimits {
+    fn name(&self) -> &'static str {
+        "TypeLimits"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_COMPARISONS,
                     OVERFLOWING_LITERALS)
@@ -76,7 +85,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
                 }
             }
             hir::ExprKind::Lit(ref lit) => {
-                match cx.tables.node_id_to_type(e.hir_id).sty {
+                match cx.tables.node_type(e.hir_id).sty {
                     ty::Int(t) => {
                         match lit.node {
                             ast::LitKind::Int(v, ast::LitIntType::Signed(_)) |
@@ -137,7 +146,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
                                                              OVERFLOWING_LITERALS,
                                                              parent_expr.span,
                                                              "only u8 can be cast into char");
-                                        err.span_suggestion_with_applicability(
+                                        err.span_suggestion(
                                             parent_expr.span,
                                             &"use a char literal instead",
                                             format!("'\\u{{{:X}}}'", lit_val),
@@ -235,7 +244,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
             }
         }
 
-        fn check_limits(cx: &LateContext,
+        fn check_limits(cx: &LateContext<'_, '_>,
                         binop: hir::BinOp,
                         l: &hir::Expr,
                         r: &hir::Expr)
@@ -248,7 +257,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
             // Normalize the binop so that the literal is always on the RHS in
             // the comparison
             let norm_binop = if swap { rev_binop(binop) } else { binop };
-            match cx.tables.node_id_to_type(expr.hir_id).sty {
+            match cx.tables.node_type(expr.hir_id).sty {
                 ty::Int(int_ty) => {
                     let (min, max) = int_ty_range(int_ty);
                     let lit_val: i128 = match lit.node {
@@ -292,7 +301,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
             }
         }
 
-        fn get_bin_hex_repr(cx: &LateContext, lit: &ast::Lit) -> Option<String> {
+        fn get_bin_hex_repr(cx: &LateContext<'_, '_>, lit: &ast::Lit) -> Option<String> {
             let src = cx.sess().source_map().span_to_snippet(lit.span).ok()?;
             let firstch = src.chars().next()?;
 
@@ -314,7 +323,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
         //
         // No suggestion for: `isize`, `usize`.
         fn get_type_suggestion<'a>(
-            t: &ty::TyKind,
+            t: &ty::TyKind<'_>,
             val: u128,
             negative: bool,
         ) -> Option<String> {
@@ -358,9 +367,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
         }
 
         fn report_bin_hex_error(
-            cx: &LateContext,
+            cx: &LateContext<'_, '_>,
             expr: &hir::Expr,
-            ty: ty::TyKind,
+            ty: ty::TyKind<'_>,
             repr_str: String,
             val: u128,
             negative: bool,
@@ -368,14 +377,14 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
             let (t, actually) = match ty {
                 ty::Int(t) => {
                     let ity = attr::IntType::SignedInt(t);
-                    let bits = layout::Integer::from_attr(&cx.tcx, ity).size().bits();
-                    let actually = (val << (128 - bits)) as i128 >> (128 - bits);
+                    let size = layout::Integer::from_attr(&cx.tcx, ity).size();
+                    let actually = sign_extend(val, size) as i128;
                     (format!("{:?}", t), actually.to_string())
                 }
                 ty::Uint(t) => {
                     let ity = attr::IntType::UnsignedInt(t);
-                    let bits = layout::Integer::from_attr(&cx.tcx, ity).size().bits();
-                    let actually = (val << (128 - bits)) >> (128 - bits);
+                    let size = layout::Integer::from_attr(&cx.tcx, ity).size();
+                    let actually = truncate(val, size);
                     (format!("{:?}", t), actually.to_string())
                 }
                 _ => bug!(),
@@ -391,11 +400,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeLimits {
                 repr_str, val, t, actually, t
             ));
             if let Some(sugg_ty) =
-                get_type_suggestion(&cx.tables.node_id_to_type(expr.hir_id).sty, val, negative)
+                get_type_suggestion(&cx.tables.node_type(expr.hir_id).sty, val, negative)
             {
                 if let Some(pos) = repr_str.chars().position(|c| c == 'i' || c == 'u') {
                     let (sans_suffix, _) = repr_str.split_at(pos);
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         expr.span,
                         &format!("consider using `{}` instead", sugg_ty),
                         format!("{}{}", sans_suffix, sugg_ty),
@@ -470,12 +479,12 @@ fn is_repr_nullable_ptr<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 }
 
 impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
-    /// Check if the given type is "ffi-safe" (has a stable, well-defined
+    /// Checks if the given type is "ffi-safe" (has a stable, well-defined
     /// representation which can be exported to C code).
     fn check_type_for_ffi(&self,
                           cache: &mut FxHashSet<Ty<'tcx>>,
                           ty: Ty<'tcx>) -> FfiResult<'tcx> {
-        use self::FfiResult::*;
+        use FfiResult::*;
 
         let cx = self.cx.tcx;
 
@@ -783,13 +792,17 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
 pub struct ImproperCTypes;
 
 impl LintPass for ImproperCTypes {
+    fn name(&self) -> &'static str {
+        "ImproperCTypes"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(IMPROPER_CTYPES)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
-    fn check_foreign_item(&mut self, cx: &LateContext, it: &hir::ForeignItem) {
+    fn check_foreign_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::ForeignItem) {
         let mut vis = ImproperCTypesVisitor { cx };
         let abi = cx.tcx.hir().get_foreign_abi(it.id);
         if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
@@ -809,13 +822,17 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
 pub struct VariantSizeDifferences;
 
 impl LintPass for VariantSizeDifferences {
+    fn name(&self) -> &'static str {
+        "VariantSizeDifferences"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(VARIANT_SIZE_DIFFERENCES)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for VariantSizeDifferences {
-    fn check_item(&mut self, cx: &LateContext, it: &hir::Item) {
+    fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) {
         if let hir::ItemKind::Enum(ref enum_definition, _) = it.node {
             let item_def_id = cx.tcx.hir().local_def_id(it.id);
             let t = cx.tcx.type_of(item_def_id);
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index bc29020e79f2a..407e684293515 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -1,5 +1,6 @@
 use rustc::hir::def::Def;
 use rustc::hir::def_id::DefId;
+use rustc::lint;
 use rustc::ty;
 use rustc::ty::adjustment;
 use lint::{LateContext, EarlyContext, LintContext, LintArray};
@@ -16,6 +17,8 @@ use syntax_pos::Span;
 
 use rustc::hir;
 
+use log::debug;
+
 declare_lint! {
     pub UNUSED_MUST_USE,
     Warn,
@@ -33,15 +36,19 @@ declare_lint! {
 pub struct UnusedResults;
 
 impl LintPass for UnusedResults {
+    fn name(&self) -> &'static str {
+        "UnusedResults"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_MUST_USE, UNUSED_RESULTS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
-    fn check_stmt(&mut self, cx: &LateContext, s: &hir::Stmt) {
+    fn check_stmt(&mut self, cx: &LateContext<'_, '_>, s: &hir::Stmt) {
         let expr = match s.node {
-            hir::StmtKind::Semi(ref expr, _) => &**expr,
+            hir::StmtKind::Semi(ref expr) => &**expr,
             _ => return,
         };
 
@@ -164,7 +171,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
         }
 
         fn check_must_use(
-            cx: &LateContext,
+            cx: &LateContext<'_, '_>,
             def_id: DefId,
             sp: Span,
             descr_pre_path: &str,
@@ -198,14 +205,18 @@ declare_lint! {
 pub struct PathStatements;
 
 impl LintPass for PathStatements {
+    fn name(&self) -> &'static str {
+        "PathStatements"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(PATH_STATEMENTS)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for PathStatements {
-    fn check_stmt(&mut self, cx: &LateContext, s: &hir::Stmt) {
-        if let hir::StmtKind::Semi(ref expr, _) = s.node {
+    fn check_stmt(&mut self, cx: &LateContext<'_, '_>, s: &hir::Stmt) {
+        if let hir::StmtKind::Semi(ref expr) = s.node {
             if let hir::ExprKind::Path(_) = expr.node {
                 cx.span_lint(PATH_STATEMENTS, s.span, "path statement with no effect");
             }
@@ -223,13 +234,17 @@ declare_lint! {
 pub struct UnusedAttributes;
 
 impl LintPass for UnusedAttributes {
+    fn name(&self) -> &'static str {
+        "UnusedAttributes"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_ATTRIBUTES)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAttributes {
-    fn check_attribute(&mut self, cx: &LateContext, attr: &ast::Attribute) {
+    fn check_attribute(&mut self, cx: &LateContext<'_, '_>, attr: &ast::Attribute) {
         debug!("checking attribute: {:?}", attr);
         // Note that check_name() marks the attribute as used if it matches.
         for &(name, ty, ..) in BUILTIN_ATTRIBUTES {
@@ -291,7 +306,7 @@ pub struct UnusedParens;
 
 impl UnusedParens {
     fn check_unused_parens_expr(&self,
-                                cx: &EarlyContext,
+                                cx: &EarlyContext<'_>,
                                 value: &ast::Expr,
                                 msg: &str,
                                 followed_by_block: bool) {
@@ -313,7 +328,7 @@ impl UnusedParens {
     }
 
     fn check_unused_parens_pat(&self,
-                                cx: &EarlyContext,
+                                cx: &EarlyContext<'_>,
                                 value: &ast::Pat,
                                 msg: &str) {
         if let ast::PatKind::Paren(_) = value.node {
@@ -327,7 +342,7 @@ impl UnusedParens {
         }
     }
 
-    fn remove_outer_parens(cx: &EarlyContext, span: Span, pattern: &str, msg: &str) {
+    fn remove_outer_parens(cx: &EarlyContext<'_>, span: Span, pattern: &str, msg: &str) {
         let span_msg = format!("unnecessary parentheses around {}", msg);
         let mut err = cx.struct_span_lint(UNUSED_PARENS, span, &span_msg);
         let mut ate_left_paren = false;
@@ -354,24 +369,28 @@ impl UnusedParens {
                     _ => false,
                 }
             }).to_owned();
-        err.span_suggestion_short_with_applicability(
-                span,
-                "remove these parentheses",
-                parens_removed,
-                Applicability::MachineApplicable
-            );
+        err.span_suggestion_short(
+            span,
+            "remove these parentheses",
+            parens_removed,
+            Applicability::MachineApplicable,
+        );
         err.emit();
     }
 }
 
 impl LintPass for UnusedParens {
+    fn name(&self) -> &'static str {
+        "UnusedParens"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_PARENS)
     }
 }
 
 impl EarlyLintPass for UnusedParens {
-    fn check_expr(&mut self, cx: &EarlyContext, e: &ast::Expr) {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
         use syntax::ast::ExprKind::*;
         let (value, msg, followed_by_block) = match e.node {
             If(ref cond, ..) => (cond, "`if` condition", true),
@@ -413,7 +432,7 @@ impl EarlyLintPass for UnusedParens {
         self.check_unused_parens_expr(cx, &value, msg, followed_by_block);
     }
 
-    fn check_pat(&mut self, cx: &EarlyContext, p: &ast::Pat, _: &mut bool) {
+    fn check_pat(&mut self, cx: &EarlyContext<'_>, p: &ast::Pat, _: &mut bool) {
         use ast::PatKind::{Paren, Range};
         // The lint visitor will visit each subpattern of `p`. We do not want to lint any range
         // pattern no matter where it occurs in the pattern. For something like `&(a..=b)`, there
@@ -427,7 +446,7 @@ impl EarlyLintPass for UnusedParens {
         }
     }
 
-    fn check_stmt(&mut self, cx: &EarlyContext, s: &ast::Stmt) {
+    fn check_stmt(&mut self, cx: &EarlyContext<'_>, s: &ast::Stmt) {
         if let ast::StmtKind::Local(ref local) = s.node {
             if let Some(ref value) = local.init {
                 self.check_unused_parens_expr(cx, &value, "assigned value", false);
@@ -446,7 +465,7 @@ declare_lint! {
 pub struct UnusedImportBraces;
 
 impl UnusedImportBraces {
-    fn check_use_tree(&self, cx: &EarlyContext, use_tree: &ast::UseTree, item: &ast::Item) {
+    fn check_use_tree(&self, cx: &EarlyContext<'_>, use_tree: &ast::UseTree, item: &ast::Item) {
         if let ast::UseTreeKind::Nested(ref items) = use_tree.kind {
             // Recursively check nested UseTrees
             for &(ref tree, _) in items {
@@ -483,13 +502,17 @@ impl UnusedImportBraces {
 }
 
 impl LintPass for UnusedImportBraces {
+    fn name(&self) -> &'static str {
+        "UnusedImportBraces"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_IMPORT_BRACES)
     }
 }
 
 impl EarlyLintPass for UnusedImportBraces {
-    fn check_item(&mut self, cx: &EarlyContext, item: &ast::Item) {
+    fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
         if let ast::ItemKind::Use(ref use_tree) = item.node {
             self.check_use_tree(cx, use_tree, item);
         }
@@ -506,13 +529,17 @@ declare_lint! {
 pub struct UnusedAllocation;
 
 impl LintPass for UnusedAllocation {
+    fn name(&self) -> &'static str {
+        "UnusedAllocation"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(UNUSED_ALLOCATION)
     }
 }
 
 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedAllocation {
-    fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) {
+    fn check_expr(&mut self, cx: &LateContext<'_, '_>, e: &hir::Expr) {
         match e.node {
             hir::ExprKind::Box(_) => {}
             _ => return,
diff --git a/src/librustc_llvm/Cargo.toml b/src/librustc_llvm/Cargo.toml
index 013badb71cc5a..0fe327d5deeeb 100644
--- a/src/librustc_llvm/Cargo.toml
+++ b/src/librustc_llvm/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 name = "rustc_llvm"
 version = "0.0.0"
 build = "build.rs"
+edition = "2018"
 
 [lib]
 name = "rustc_llvm"
diff --git a/src/librustc_llvm/build.rs b/src/librustc_llvm/build.rs
index d4a3ae273fcd4..7fa83dd977950 100644
--- a/src/librustc_llvm/build.rs
+++ b/src/librustc_llvm/build.rs
@@ -1,6 +1,3 @@
-extern crate cc;
-extern crate build_helper;
-
 use std::process::Command;
 use std::env;
 use std::path::{PathBuf, Path};
@@ -24,6 +21,8 @@ fn main() {
         return;
     }
 
+    build_helper::restore_library_path();
+
     let target = env::var("TARGET").expect("TARGET was not set");
     let llvm_config = env::var_os("LLVM_CONFIG")
         .map(PathBuf::from)
@@ -243,6 +242,8 @@ fn main() {
         "c++"
     } else if target.contains("freebsd") {
         "c++"
+    } else if target.contains("darwin") {
+        "c++"
     } else if target.contains("netbsd") && llvm_static_stdcpp.is_some() {
         // NetBSD uses a separate library when relocation is required
         "stdc++_pic"
diff --git a/src/librustc_llvm/lib.rs b/src/librustc_llvm/lib.rs
index ca66540fa25f7..292ce8b0a01b0 100644
--- a/src/librustc_llvm/lib.rs
+++ b/src/librustc_llvm/lib.rs
@@ -1,9 +1,8 @@
+#![deny(rust_2018_idioms)]
 #![feature(nll)]
 #![feature(static_nobundle)]
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 // See librustc_cratesio_shim/Cargo.toml for a comment explaining this.
 #[allow(unused_extern_crates)]
diff --git a/src/librustc_lsan/Cargo.toml b/src/librustc_lsan/Cargo.toml
index a8e11df7670cf..9ad53ee6d0958 100644
--- a/src/librustc_lsan/Cargo.toml
+++ b/src/librustc_lsan/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 build = "build.rs"
 name = "rustc_lsan"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_lsan"
diff --git a/src/librustc_lsan/build.rs b/src/librustc_lsan/build.rs
index 470f2bb3e5c85..b8c7b7c2d5537 100644
--- a/src/librustc_lsan/build.rs
+++ b/src/librustc_lsan/build.rs
@@ -1,6 +1,3 @@
-extern crate build_helper;
-extern crate cmake;
-
 use std::env;
 use build_helper::sanitizer_lib_boilerplate;
 
@@ -8,6 +5,8 @@ use cmake::Config;
 
 fn main() {
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
+        build_helper::restore_library_path();
+
         let (native, target) = match sanitizer_lib_boilerplate("lsan") {
             Ok(native) => native,
             _ => return,
diff --git a/src/librustc_lsan/lib.rs b/src/librustc_lsan/lib.rs
index d6c8e54c18db7..3bdb86d313dcb 100644
--- a/src/librustc_lsan/lib.rs
+++ b/src/librustc_lsan/lib.rs
@@ -6,3 +6,5 @@
 #![unstable(feature = "sanitizer_runtime_lib",
             reason = "internal implementation detail of sanitizers",
             issue = "0")]
+
+#![deny(rust_2018_idioms)]
diff --git a/src/librustc_metadata/Cargo.toml b/src/librustc_metadata/Cargo.toml
index 337c87c24ba2b..e234f4f880703 100644
--- a/src/librustc_metadata/Cargo.toml
+++ b/src/librustc_metadata/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_metadata"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_metadata"
@@ -14,7 +15,7 @@ log = "0.4"
 memmap = "0.6"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_target = { path = "../librustc_target" }
 serialize = { path = "../libserialize" }
 stable_deref_trait = "1.0.0"
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index e9785e7c88d0d..6f2718381c2ec 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -1,9 +1,9 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
-use cstore::{self, CStore, CrateSource, MetadataBlob};
-use locator::{self, CratePaths};
-use decoder::proc_macro_def_path_table;
-use schema::CrateRoot;
+use crate::cstore::{self, CStore, CrateSource, MetadataBlob};
+use crate::locator::{self, CratePaths};
+use crate::decoder::proc_macro_def_path_table;
+use crate::schema::CrateRoot;
 use rustc_data_structures::sync::{Lrc, RwLock, Lock};
 
 use rustc::hir::def_id::CrateNum;
@@ -29,8 +29,9 @@ use syntax::attr;
 use syntax::ext::base::SyntaxExtension;
 use syntax::symbol::Symbol;
 use syntax::visit;
+use syntax::{span_err, span_fatal};
 use syntax_pos::{Span, DUMMY_SP};
-use log;
+use log::{debug, info, log_enabled};
 
 pub struct Library {
     pub dylib: Option<(PathBuf, PathKind)>,
@@ -342,7 +343,7 @@ impl<'a> CrateLoader<'a> {
         }
     }
 
-    fn load(&mut self, locate_ctxt: &mut locator::Context) -> Option<LoadResult> {
+    fn load(&mut self, locate_ctxt: &mut locator::Context<'_>) -> Option<LoadResult> {
         let library = locate_ctxt.maybe_load_library_crate()?;
 
         // In the case that we're loading a crate, but not matching
@@ -427,7 +428,7 @@ impl<'a> CrateLoader<'a> {
         // The map from crate numbers in the crate we're resolving to local crate numbers.
         // We map 0 and all other holes in the map to our parent crate. The "additional"
         // self-dependencies should be harmless.
-        ::std::iter::once(krate).chain(crate_root.crate_deps
+        std::iter::once(krate).chain(crate_root.crate_deps
                                                  .decode(metadata)
                                                  .map(|dep| {
             info!("resolving dep crate {} hash: `{}` extra filename: `{}`", dep.name, dep.hash,
@@ -512,7 +513,7 @@ impl<'a> CrateLoader<'a> {
         }
     }
 
-    /// Load custom derive macros.
+    /// Loads custom derive macros.
     ///
     /// Note that this is intentionally similar to how we load plugins today,
     /// but also intentionally separate. Plugins are likely always going to be
@@ -522,7 +523,7 @@ impl<'a> CrateLoader<'a> {
     fn load_derive_macros(&mut self, root: &CrateRoot, dylib: Option<PathBuf>, span: Span)
                           -> Vec<(ast::Name, Lrc<SyntaxExtension>)> {
         use std::{env, mem};
-        use dynamic_lib::DynamicLibrary;
+        use crate::dynamic_lib::DynamicLibrary;
         use proc_macro::bridge::client::ProcMacro;
         use syntax_ext::deriving::custom::ProcMacroDerive;
         use syntax_ext::proc_macro_impl::{AttrProcMacro, BangProcMacro};
@@ -569,7 +570,7 @@ impl<'a> CrateLoader<'a> {
                 ProcMacro::Bang { name, client } => {
                     (name, SyntaxExtension::ProcMacro {
                         expander: Box::new(BangProcMacro { client }),
-                        allow_internal_unstable: false,
+                        allow_internal_unstable: None,
                         edition: root.edition,
                     })
                 }
@@ -996,7 +997,7 @@ impl<'a> CrateLoader<'a> {
                        item.ident, orig_name);
                 let orig_name = match orig_name {
                     Some(orig_name) => {
-                        ::validate_crate_name(Some(self.sess), &orig_name.as_str(),
+                        crate::validate_crate_name(Some(self.sess), &orig_name.as_str(),
                                             Some(item.span));
                         orig_name
                     }
diff --git a/src/librustc_metadata/cstore.rs b/src/librustc_metadata/cstore.rs
index 543fb5d5df5be..d646879b4d45d 100644
--- a/src/librustc_metadata/cstore.rs
+++ b/src/librustc_metadata/cstore.rs
@@ -1,7 +1,7 @@
 // The crate store - a central repo for information collected about external
 // crates and libraries
 
-use schema;
+use crate::schema;
 use rustc::hir::def_id::{CrateNum, DefIndex};
 use rustc::hir::map::definitions::DefPathTable;
 use rustc::middle::cstore::{DepKind, ExternCrate, MetadataLoader};
@@ -19,7 +19,7 @@ pub use rustc::middle::cstore::{NativeLibrary, NativeLibraryKind, LinkagePrefere
 pub use rustc::middle::cstore::NativeLibraryKind::*;
 pub use rustc::middle::cstore::{CrateSource, LibSource, ForeignModule};
 
-pub use cstore_impl::{provide, provide_extern};
+pub use crate::cstore_impl::{provide, provide_extern};
 
 // A map from external crate numbers (as decoded from some crate file) to
 // local crate numbers (as generated during this session). Each external
@@ -46,7 +46,7 @@ pub struct CrateMetadata {
     /// Original name of the crate.
     pub name: Symbol,
 
-    /// Name of the crate as imported.  I.e., if imported with
+    /// Name of the crate as imported. I.e., if imported with
     /// `extern crate foo as bar;` this will be `bar`.
     pub imported_name: Symbol,
 
@@ -66,9 +66,9 @@ pub struct CrateMetadata {
 
     pub root: schema::CrateRoot,
 
-    /// For each public item in this crate, we encode a key.  When the
+    /// For each public item in this crate, we encode a key. When the
     /// crate is loaded, we read all the keys and put them in this
-    /// hashmap, which gives the reverse mapping.  This allows us to
+    /// hashmap, which gives the reverse mapping. This allows us to
     /// quickly retrace a `DefPath`, which is needed for incremental
     /// compilation support.
     pub def_path_table: Lrc<DefPathTable>,
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index e61229db86ddb..f49b88f14e60e 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -1,9 +1,9 @@
-use cstore::{self, LoadedMacro};
-use encoder;
-use link_args;
-use native_libs;
-use foreign_modules;
-use schema;
+use crate::cstore::{self, LoadedMacro};
+use crate::encoder;
+use crate::link_args;
+use crate::native_libs;
+use crate::foreign_modules;
+use crate::schema;
 
 use rustc::ty::query::QueryConfig;
 use rustc::middle::cstore::{CrateStore, DepKind,
@@ -29,6 +29,7 @@ use syntax::attr;
 use syntax::source_map;
 use syntax::edition::Edition;
 use syntax::parse::source_file_to_stream;
+use syntax::parse::parser::emit_unclosed_delims;
 use syntax::symbol::Symbol;
 use syntax_pos::{Span, NO_EXPANSION, FileName};
 use rustc_data_structures::bit_set::BitSet;
@@ -51,7 +52,7 @@ macro_rules! provide {
                     index: CRATE_DEF_INDEX
                 });
                 let dep_node = def_path_hash
-                    .to_dep_node(::rustc::dep_graph::DepKind::CrateMetadata);
+                    .to_dep_node(rustc::dep_graph::DepKind::CrateMetadata);
                 // The DepNodeIndex of the DepNode::CrateMetadata should be
                 // cached somewhere, so that we can use read_index().
                 $tcx.dep_graph.read(dep_node);
@@ -421,10 +422,12 @@ impl cstore::CStore {
             use syntax::ext::base::SyntaxExtension;
             use syntax_ext::proc_macro_impl::BangProcMacro;
 
-            let client = ::proc_macro::bridge::client::Client::expand1(::proc_macro::quote);
+            let client = proc_macro::bridge::client::Client::expand1(proc_macro::quote);
             let ext = SyntaxExtension::ProcMacro {
                 expander: Box::new(BangProcMacro { client }),
-                allow_internal_unstable: true,
+                allow_internal_unstable: Some(vec![
+                    Symbol::intern("proc_macro_def_site"),
+                ].into()),
                 edition: data.root.edition,
             };
             return LoadedMacro::ProcMacro(Lrc::new(ext));
@@ -436,7 +439,8 @@ impl cstore::CStore {
 
         let source_file = sess.parse_sess.source_map().new_source_file(source_name, def.body);
         let local_span = Span::new(source_file.start_pos, source_file.end_pos, NO_EXPANSION);
-        let body = source_file_to_stream(&sess.parse_sess, source_file, None);
+        let (body, errors) = source_file_to_stream(&sess.parse_sess, source_file, None);
+        emit_unclosed_delims(&errors, &sess.diagnostic());
 
         // Mark the attrs as used
         let attrs = data.get_item_attrs(id.index, sess);
diff --git a/src/librustc_metadata/decoder.rs b/src/librustc_metadata/decoder.rs
index dc8db5be5820a..1c4e3bc6a50e7 100644
--- a/src/librustc_metadata/decoder.rs
+++ b/src/librustc_metadata/decoder.rs
@@ -1,7 +1,7 @@
 // Decoding metadata from a single crate's metadata
 
-use cstore::{self, CrateMetadata, MetadataBlob, NativeLibrary, ForeignModule};
-use schema::*;
+use crate::cstore::{self, CrateMetadata, MetadataBlob, NativeLibrary, ForeignModule};
+use crate::schema::*;
 
 use rustc_data_structures::sync::{Lrc, ReadGuard};
 use rustc::hir::map::{DefKey, DefPath, DefPathData, DefPathHash, Definitions};
@@ -34,6 +34,7 @@ use syntax::symbol::InternedString;
 use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::hygiene::Mark;
 use syntax_pos::{self, Span, BytePos, Pos, DUMMY_SP, NO_EXPANSION};
+use log::debug;
 
 pub struct DecodeContext<'a, 'tcx: 'a> {
     opaque: opaque::Decoder<'a>,
@@ -418,6 +419,7 @@ impl<'tcx> EntryKind<'tcx> {
             EntryKind::Mod(_) => Def::Mod(did),
             EntryKind::Variant(_) => Def::Variant(did),
             EntryKind::Trait(_) => Def::Trait(did),
+            EntryKind::TraitAlias(_) => Def::TraitAlias(did),
             EntryKind::Enum(..) => Def::Enum(did),
             EntryKind::MacroDef(_) => Def::Macro(did, MacroKind::Bang),
             EntryKind::ForeignType => Def::ForeignTy(did),
@@ -432,7 +434,7 @@ impl<'tcx> EntryKind<'tcx> {
     }
 }
 
-/// Create the "fake" DefPathTable for a given proc macro crate.
+/// Creates the "fake" DefPathTable for a given proc macro crate.
 ///
 /// The DefPathTable is as follows:
 ///
@@ -520,22 +522,31 @@ impl<'a, 'tcx> CrateMetadata {
     }
 
     pub fn get_trait_def(&self, item_id: DefIndex, sess: &Session) -> ty::TraitDef {
-        let data = match self.entry(item_id).kind {
-            EntryKind::Trait(data) => data.decode((self, sess)),
-            _ => bug!(),
-        };
-
-        ty::TraitDef::new(self.local_def_id(item_id),
-                          data.unsafety,
-                          data.paren_sugar,
-                          data.has_auto_impl,
-                          data.is_marker,
-                          self.def_path_table.def_path_hash(item_id))
+        match self.entry(item_id).kind {
+            EntryKind::Trait(data) => {
+                let data = data.decode((self, sess));
+                ty::TraitDef::new(self.local_def_id(item_id),
+                                  data.unsafety,
+                                  data.paren_sugar,
+                                  data.has_auto_impl,
+                                  data.is_marker,
+                                  self.def_path_table.def_path_hash(item_id))
+            },
+            EntryKind::TraitAlias(_) => {
+                ty::TraitDef::new(self.local_def_id(item_id),
+                                  hir::Unsafety::Normal,
+                                  false,
+                                  false,
+                                  false,
+                                  self.def_path_table.def_path_hash(item_id))
+            },
+            _ => bug!("def-index does not refer to trait or trait alias"),
+        }
     }
 
     fn get_variant(&self,
                    tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                   item: &Entry,
+                   item: &Entry<'_>,
                    index: DefIndex,
                    adt_kind: ty::AdtKind)
                    -> ty::VariantDef
@@ -615,10 +626,13 @@ impl<'a, 'tcx> CrateMetadata {
                                 item_id: DefIndex,
                                 tcx: TyCtxt<'a, 'tcx, 'tcx>)
                                 -> ty::GenericPredicates<'tcx> {
-        match self.entry(item_id).kind {
-            EntryKind::Trait(data) => data.decode(self).super_predicates.decode((self, tcx)),
-            _ => bug!(),
-        }
+        let super_predicates = match self.entry(item_id).kind {
+            EntryKind::Trait(data) => data.decode(self).super_predicates,
+            EntryKind::TraitAlias(data) => data.decode(self).super_predicates,
+            _ => bug!("def-index does not refer to trait or trait alias"),
+        };
+
+        super_predicates.decode((self, tcx))
     }
 
     pub fn get_generics(&self,
@@ -880,6 +894,9 @@ impl<'a, 'tcx> CrateMetadata {
             EntryKind::AssociatedType(container) => {
                 (ty::AssociatedKind::Type, container, false)
             }
+            EntryKind::AssociatedExistential(container) => {
+                (ty::AssociatedKind::Existential, container, false)
+            }
             _ => bug!("cannot get associated-item of `{:?}`", def_key)
         };
 
@@ -1014,7 +1031,8 @@ impl<'a, 'tcx> CrateMetadata {
         }
         def_key.parent.and_then(|parent_index| {
             match self.entry(parent_index).kind {
-                EntryKind::Trait(_) => Some(self.local_def_id(parent_index)),
+                EntryKind::Trait(_) |
+                EntryKind::TraitAlias(_) => Some(self.local_def_id(parent_index)),
                 _ => None,
             }
         })
diff --git a/src/librustc_metadata/diagnostics.rs b/src/librustc_metadata/diagnostics.rs
index 1b1852434740c..9ac582ebc42da 100644
--- a/src/librustc_metadata/diagnostics.rs
+++ b/src/librustc_metadata/diagnostics.rs
@@ -1,5 +1,7 @@
 #![allow(non_snake_case)]
 
+use syntax::{register_diagnostic, register_diagnostics, register_long_diagnostics};
+
 register_long_diagnostics! {
 E0454: r##"
 A link name was given with an empty name. Erroneous code example:
@@ -35,7 +37,7 @@ extern {}
 ```
 
 See more:
-https://doc.rust-lang.org/book/first-edition/conditional-compilation.html
+https://doc.rust-lang.org/reference/attributes.html#conditional-compilation
 "##,
 
 E0458: r##"
diff --git a/src/librustc_metadata/dynamic_lib.rs b/src/librustc_metadata/dynamic_lib.rs
index 7d1c3c09d33e9..9dd160c24c373 100644
--- a/src/librustc_metadata/dynamic_lib.rs
+++ b/src/librustc_metadata/dynamic_lib.rs
@@ -32,7 +32,7 @@ impl DynamicLibrary {
         }
     }
 
-    /// Load a dynamic library into the global namespace (RTLD_GLOBAL on Unix)
+    /// Loads a dynamic library into the global namespace (RTLD_GLOBAL on Unix)
     /// and do it now (don't use RTLD_LAZY on Unix).
     pub fn open_global_now(filename: &Path) -> Result<DynamicLibrary, String> {
         let maybe_library = dl::open_global_now(filename.as_os_str());
@@ -76,7 +76,6 @@ impl DynamicLibrary {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use libc;
     use std::mem;
 
     #[test]
@@ -127,7 +126,6 @@ mod tests {
 
 #[cfg(unix)]
 mod dl {
-    use libc;
     use std::ffi::{CStr, OsStr, CString};
     use std::os::unix::prelude::*;
     use std::ptr;
diff --git a/src/librustc_metadata/encoder.rs b/src/librustc_metadata/encoder.rs
index 2de1637fb0d9d..776adc077fc08 100644
--- a/src/librustc_metadata/encoder.rs
+++ b/src/librustc_metadata/encoder.rs
@@ -1,7 +1,7 @@
-use index::Index;
-use index_builder::{FromId, IndexBuilder, Untracked};
-use isolated_encoder::IsolatedEncoder;
-use schema::*;
+use crate::index::Index;
+use crate::index_builder::{FromId, IndexBuilder, Untracked};
+use crate::isolated_encoder::IsolatedEncoder;
+use crate::schema::*;
 
 use rustc::middle::cstore::{LinkagePreference, NativeLibrary,
                             EncodedMetadata, ForeignModule};
@@ -34,6 +34,7 @@ use syntax::attr;
 use syntax::source_map::Spanned;
 use syntax::symbol::keywords;
 use syntax_pos::{self, hygiene, FileName, SourceFile, Span};
+use log::{debug, trace};
 
 use rustc::hir::{self, PatKind};
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
@@ -673,7 +674,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
         let def_id = field.did;
         debug!("IsolatedEncoder::encode_field({:?})", def_id);
 
-        let variant_id = tcx.hir().as_local_node_id(variant.did).unwrap();
+        let variant_id = tcx.hir().as_local_hir_id(variant.did).unwrap();
         let variant_data = tcx.hir().expect_variant_data(variant_id);
 
         Entry {
@@ -977,7 +978,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
             let body = self.tcx.hir().body(body_id);
             self.lazy_seq(body.arguments.iter().map(|arg| {
                 match arg.pat.node {
-                    PatKind::Binding(_, _, ident, _) => ident.name,
+                    PatKind::Binding(_, _, _, ident, _) => ident.name,
                     _ => keywords::Invalid.name(),
                 }
             }))
@@ -1128,8 +1129,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
 
                 EntryKind::Impl(self.lazy(&data))
             }
-            hir::ItemKind::Trait(..) |
-            hir::ItemKind::TraitAlias(..) => {
+            hir::ItemKind::Trait(..) => {
                 let trait_def = tcx.trait_def(def_id);
                 let data = TraitData {
                     unsafety: trait_def.unsafety,
@@ -1141,6 +1141,13 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
 
                 EntryKind::Trait(self.lazy(&data))
             }
+            hir::ItemKind::TraitAlias(..) => {
+                let data = TraitAliasData {
+                    super_predicates: self.lazy(&tcx.super_predicates_of(def_id)),
+                };
+
+                EntryKind::TraitAlias(self.lazy(&data))
+            }
             hir::ItemKind::ExternCrate(_) |
             hir::ItemKind::Use(..) => bug!("cannot encode info for item {:?}", item),
         };
@@ -1214,6 +1221,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                 hir::ItemKind::Impl(..) |
                 hir::ItemKind::Existential(..) |
                 hir::ItemKind::Trait(..) => Some(self.encode_generics(def_id)),
+                hir::ItemKind::TraitAlias(..) => Some(self.encode_generics(def_id)),
                 _ => None,
             },
             predicates: match item.node {
@@ -1226,7 +1234,8 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
                 hir::ItemKind::Union(..) |
                 hir::ItemKind::Impl(..) |
                 hir::ItemKind::Existential(..) |
-                hir::ItemKind::Trait(..) => Some(self.encode_predicates(def_id)),
+                hir::ItemKind::Trait(..) |
+                hir::ItemKind::TraitAlias(..) => Some(self.encode_predicates(def_id)),
                 _ => None,
             },
 
@@ -1236,7 +1245,8 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
             // hack. (No reason not to expand it in the future if
             // necessary.)
             predicates_defined_on: match item.node {
-                hir::ItemKind::Trait(..) => Some(self.encode_predicates_defined_on(def_id)),
+                hir::ItemKind::Trait(..) |
+                hir::ItemKind::TraitAlias(..) => Some(self.encode_predicates_defined_on(def_id)),
                 _ => None, // not *wrong* for other kinds of items, but not needed
             },
 
@@ -1321,6 +1331,29 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
         }
     }
 
+    fn encode_info_for_const_param(&mut self, def_id: DefId) -> Entry<'tcx> {
+        debug!("IsolatedEncoder::encode_info_for_const_param({:?})", def_id);
+        let tcx = self.tcx;
+        Entry {
+            kind: EntryKind::Type,
+            visibility: self.lazy(&ty::Visibility::Public),
+            span: self.lazy(&tcx.def_span(def_id)),
+            attributes: LazySeq::empty(),
+            children: LazySeq::empty(),
+            stability: None,
+            deprecation: None,
+
+            ty: Some(self.encode_item_type(def_id)),
+            inherent_impls: LazySeq::empty(),
+            variances: LazySeq::empty(),
+            generics: None,
+            predicates: None,
+            predicates_defined_on: None,
+
+            mir: None,
+        }
+    }
+
     fn encode_info_for_closure(&mut self, def_id: DefId) -> Entry<'tcx> {
         debug!("IsolatedEncoder::encode_info_for_closure({:?})", def_id);
         let tcx = self.tcx;
@@ -1328,7 +1361,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
         let tables = self.tcx.typeck_tables_of(def_id);
         let node_id = self.tcx.hir().as_local_node_id(def_id).unwrap();
         let hir_id = self.tcx.hir().node_to_hir_id(node_id);
-        let kind = match tables.node_id_to_type(hir_id).sty {
+        let kind = match tables.node_type(hir_id).sty {
             ty::Generator(def_id, ..) => {
                 let layout = self.tcx.generator_layout(def_id);
                 let data = GeneratorData {
@@ -1512,7 +1545,7 @@ impl<'a, 'b: 'a, 'tcx: 'b> IsolatedEncoder<'a, 'b, 'tcx> {
     // symbol associated with them (they weren't translated) or if they're an FFI
     // definition (as that's not defined in this crate).
     fn encode_exported_symbols(&mut self,
-                               exported_symbols: &[(ExportedSymbol, SymbolExportLevel)])
+                               exported_symbols: &[(ExportedSymbol<'_>, SymbolExportLevel)])
                                -> EncodedExportedSymbols {
         // The metadata symbol name is special. It should not show up in
         // downstream crates.
@@ -1674,6 +1707,11 @@ impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
                     let encode_info = IsolatedEncoder::encode_info_for_ty_param;
                     self.record(def_id, encode_info, (def_id, has_default));
                 }
+                hir::GenericParamKind::Const { .. } => {
+                    let def_id = self.tcx.hir().local_def_id(param.id);
+                    let encode_info = IsolatedEncoder::encode_info_for_const_param;
+                    self.record(def_id, encode_info, def_id);
+                }
             }
         }
     }
diff --git a/src/librustc_metadata/index.rs b/src/librustc_metadata/index.rs
index ccf398241b191..18f30383090cd 100644
--- a/src/librustc_metadata/index.rs
+++ b/src/librustc_metadata/index.rs
@@ -1,9 +1,10 @@
-use schema::*;
+use crate::schema::*;
 
 use rustc::hir::def_id::{DefId, DefIndex, DefIndexAddressSpace};
 use rustc_serialize::opaque::Encoder;
 use std::slice;
 use std::u32;
+use log::debug;
 
 /// While we are generating the metadata, we also track the position
 /// of each DefIndex. It is not required that all definitions appear
@@ -24,12 +25,12 @@ impl Index {
         }
     }
 
-    pub fn record(&mut self, def_id: DefId, entry: Lazy<Entry>) {
+    pub fn record(&mut self, def_id: DefId, entry: Lazy<Entry<'_>>) {
         assert!(def_id.is_local());
         self.record_index(def_id.index, entry);
     }
 
-    pub fn record_index(&mut self, item: DefIndex, entry: Lazy<Entry>) {
+    pub fn record_index(&mut self, item: DefIndex, entry: Lazy<Entry<'_>>) {
         assert!(entry.position < (u32::MAX as usize));
         let position = entry.position as u32;
         let space_index = item.address_space().index();
diff --git a/src/librustc_metadata/index_builder.rs b/src/librustc_metadata/index_builder.rs
index 3608b12aea934..9aff1133ea920 100644
--- a/src/librustc_metadata/index_builder.rs
+++ b/src/librustc_metadata/index_builder.rs
@@ -3,7 +3,7 @@
 //!
 //! ```
 //! <common::data> // big list of item-like things...
-//!    <common::data_item> // ...for most def-ids, there is an entry.
+//!    <common::data_item> // ...for most `DefId`s, there is an entry.
 //!    </common::data_item>
 //! </common::data>
 //! ```
@@ -45,10 +45,10 @@
 //! give a callback fn, rather than taking a closure: it allows us to
 //! easily control precisely what data is given to that fn.
 
-use encoder::EncodeContext;
-use index::Index;
-use schema::*;
-use isolated_encoder::IsolatedEncoder;
+use crate::encoder::EncodeContext;
+use crate::index::Index;
+use crate::schema::*;
+use crate::isolated_encoder::IsolatedEncoder;
 
 use rustc::hir;
 use rustc::hir::def_id::DefId;
@@ -85,7 +85,7 @@ impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
         }
     }
 
-    /// Emit the data for a def-id to the metadata. The function to
+    /// Emit the data for a `DefId` to the metadata. The function to
     /// emit the data is `op`, and it will be given `data` as
     /// arguments. This `record` function will call `op` to generate
     /// the `Entry` (which may point to other encoded information)
@@ -129,25 +129,25 @@ impl<'a, 'b, 'tcx> IndexBuilder<'a, 'b, 'tcx> {
 }
 
 /// Trait used for data that can be passed from outside a dep-graph
-/// task.  The data must either be of some safe type, such as a
+/// task. The data must either be of some safe type, such as a
 /// `DefId` index, or implement the `read` method so that it can add
 /// a read of whatever dep-graph nodes are appropriate.
 pub trait DepGraphRead {
-    fn read(&self, tcx: TyCtxt);
+    fn read(&self, tcx: TyCtxt<'_, '_, '_>);
 }
 
 impl DepGraphRead for DefId {
-    fn read(&self, _tcx: TyCtxt) {}
+    fn read(&self, _tcx: TyCtxt<'_, '_, '_>) {}
 }
 
 impl DepGraphRead for ast::NodeId {
-    fn read(&self, _tcx: TyCtxt) {}
+    fn read(&self, _tcx: TyCtxt<'_, '_, '_>) {}
 }
 
 impl<T> DepGraphRead for Option<T>
     where T: DepGraphRead
 {
-    fn read(&self, tcx: TyCtxt) {
+    fn read(&self, tcx: TyCtxt<'_, '_, '_>) {
         match *self {
             Some(ref v) => v.read(tcx),
             None => (),
@@ -158,7 +158,7 @@ impl<T> DepGraphRead for Option<T>
 impl<T> DepGraphRead for [T]
     where T: DepGraphRead
 {
-    fn read(&self, tcx: TyCtxt) {
+    fn read(&self, tcx: TyCtxt<'_, '_, '_>) {
         for i in self {
             i.read(tcx);
         }
@@ -171,7 +171,7 @@ macro_rules! read_tuple {
             where $($name: DepGraphRead),*
         {
             #[allow(non_snake_case)]
-            fn read(&self, tcx: TyCtxt) {
+            fn read(&self, tcx: TyCtxt<'_, '_, '_>) {
                 let &($(ref $name),*) = self;
                 $($name.read(tcx);)*
             }
@@ -184,7 +184,7 @@ read_tuple!(A, B, C);
 macro_rules! read_hir {
     ($t:ty) => {
         impl<'tcx> DepGraphRead for &'tcx $t {
-            fn read(&self, tcx: TyCtxt) {
+            fn read(&self, tcx: TyCtxt<'_, '_, '_>) {
                 tcx.hir().read(self.id);
             }
         }
@@ -208,17 +208,17 @@ read_hir!(hir::MacroDef);
 pub struct Untracked<T>(pub T);
 
 impl<T> DepGraphRead for Untracked<T> {
-    fn read(&self, _tcx: TyCtxt) {}
+    fn read(&self, _tcx: TyCtxt<'_, '_, '_>) {}
 }
 
 /// Newtype that can be used to package up misc data extracted from a
-/// HIR node that doesn't carry its own id. This will allow an
+/// HIR node that doesn't carry its own ID. This will allow an
 /// arbitrary `T` to be passed in, but register a read on the given
-/// node-id.
+/// `NodeId`.
 pub struct FromId<T>(pub ast::NodeId, pub T);
 
 impl<T> DepGraphRead for FromId<T> {
-    fn read(&self, tcx: TyCtxt) {
+    fn read(&self, tcx: TyCtxt<'_, '_, '_>) {
         tcx.hir().read(self.0);
     }
 }
diff --git a/src/librustc_metadata/isolated_encoder.rs b/src/librustc_metadata/isolated_encoder.rs
index c09d35d150a12..e879a73e650bb 100644
--- a/src/librustc_metadata/isolated_encoder.rs
+++ b/src/librustc_metadata/isolated_encoder.rs
@@ -1,5 +1,5 @@
-use encoder::EncodeContext;
-use schema::{Lazy, LazySeq};
+use crate::encoder::EncodeContext;
+use crate::schema::{Lazy, LazySeq};
 use rustc::ty::TyCtxt;
 use rustc_serialize::Encodable;
 
diff --git a/src/librustc_metadata/lib.rs b/src/librustc_metadata/lib.rs
index d38562c93f804..b4f68399d9feb 100644
--- a/src/librustc_metadata/lib.rs
+++ b/src/librustc_metadata/lib.rs
@@ -1,38 +1,26 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_patterns)]
 #![feature(libc)]
 #![feature(nll)]
 #![feature(proc_macro_internals)]
 #![feature(proc_macro_quote)]
-#![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(crate_visibility_modifier)]
 #![feature(specialization)]
 #![feature(rustc_private)]
 
 #![recursion_limit="256"]
 
+#![deny(rust_2018_idioms)]
+
 extern crate libc;
-#[macro_use]
-extern crate log;
-extern crate memmap;
-extern crate stable_deref_trait;
-#[macro_use]
-extern crate syntax;
-extern crate syntax_pos;
-extern crate flate2;
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
-extern crate rustc_errors as errors;
-extern crate syntax_ext;
 extern crate proc_macro;
 
 #[macro_use]
 extern crate rustc;
-extern crate rustc_target;
 #[macro_use]
 extern crate rustc_data_structures;
 
diff --git a/src/librustc_metadata/locator.rs b/src/librustc_metadata/locator.rs
index 6b49d6b9e52cb..6a1aada5ac706 100644
--- a/src/librustc_metadata/locator.rs
+++ b/src/librustc_metadata/locator.rs
@@ -27,7 +27,7 @@
 //!
 //! The reason for this is that any of B's types could be composed of C's types,
 //! any function in B could return a type from C, etc. To be able to guarantee
-//! that we can always typecheck/translate any function, we have to have
+//! that we can always type-check/translate any function, we have to have
 //! complete knowledge of the whole ecosystem, not just our immediate
 //! dependencies.
 //!
@@ -212,9 +212,9 @@
 //! no means all of the necessary details. Take a look at the rest of
 //! metadata::locator or metadata::creader for all the juicy details!
 
-use cstore::{MetadataRef, MetadataBlob};
-use creader::Library;
-use schema::{METADATA_HEADER, rustc_version};
+use crate::cstore::{MetadataRef, MetadataBlob};
+use crate::creader::Library;
+use crate::schema::{METADATA_HEADER, rustc_version};
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::svh::Svh;
@@ -226,6 +226,7 @@ use rustc::util::nodemap::FxHashMap;
 
 use errors::DiagnosticBuilder;
 use syntax::symbol::Symbol;
+use syntax::struct_span_err;
 use syntax_pos::Span;
 use rustc_target::spec::{Target, TargetTriple};
 
@@ -241,6 +242,8 @@ use flate2::read::DeflateDecoder;
 
 use rustc_data_structures::owning_ref::OwningRef;
 
+use log::{debug, info, warn};
+
 pub struct CrateMismatch {
     path: PathBuf,
     got: String,
@@ -283,7 +286,7 @@ enum CrateFlavor {
 }
 
 impl fmt::Display for CrateFlavor {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(match *self {
             CrateFlavor::Rlib => "rlib",
             CrateFlavor::Rmeta => "rmeta",
@@ -600,7 +603,7 @@ impl<'a> Context<'a> {
             }
         }
 
-        let mut err: Option<DiagnosticBuilder> = None;
+        let mut err: Option<DiagnosticBuilder<'_>> = None;
         for (lib, kind) in m {
             info!("{} reading metadata from: {}", flavor, lib.display());
             let (hash, metadata) =
@@ -915,7 +918,7 @@ fn get_metadata_section_imp(target: &Target,
     }
 }
 
-// A diagnostic function for dumping crate metadata to an output stream
+/// A diagnostic function for dumping crate metadata to an output stream.
 pub fn list_file_metadata(target: &Target,
                           path: &Path,
                           loader: &dyn MetadataLoader,
diff --git a/src/librustc_metadata/native_libs.rs b/src/librustc_metadata/native_libs.rs
index d35d64957b7b4..118fb203c69a1 100644
--- a/src/librustc_metadata/native_libs.rs
+++ b/src/librustc_metadata/native_libs.rs
@@ -9,6 +9,7 @@ use syntax::attr;
 use syntax::source_map::Span;
 use syntax::feature_gate::{self, GateIssue};
 use syntax::symbol::Symbol;
+use syntax::{span_err, struct_span_err};
 
 pub fn collect<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Vec<NativeLibrary> {
     let mut collector = Collector {
@@ -163,7 +164,7 @@ impl<'a, 'tcx> Collector<'a, 'tcx> {
            !self.tcx.features().static_nobundle {
             feature_gate::emit_feature_err(&self.tcx.sess.parse_sess,
                                            "static_nobundle",
-                                           span.unwrap(),
+                                           span.unwrap_or_else(|| syntax_pos::DUMMY_SP),
                                            GateIssue::Language,
                                            "kind=\"static-nobundle\" is feature gated");
         }
diff --git a/src/librustc_metadata/schema.rs b/src/librustc_metadata/schema.rs
index 25f499bc31984..af79ea37dff55 100644
--- a/src/librustc_metadata/schema.rs
+++ b/src/librustc_metadata/schema.rs
@@ -1,4 +1,4 @@
-use index;
+use crate::index;
 
 use rustc::hir;
 use rustc::hir::def::{self, CtorKind};
@@ -316,6 +316,7 @@ pub enum EntryKind<'tcx> {
     AssociatedType(AssociatedContainer),
     AssociatedExistential(AssociatedContainer),
     AssociatedConst(AssociatedContainer, ConstQualif, Lazy<RenderedConst>),
+    TraitAlias(Lazy<TraitAliasData<'tcx>>),
 }
 
 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for EntryKind<'gcx> {
@@ -370,6 +371,9 @@ impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for EntryKind<'gcx> {
             EntryKind::Trait(ref trait_data) => {
                 trait_data.hash_stable(hcx, hasher);
             }
+            EntryKind::TraitAlias(ref trait_alias_data) => {
+                trait_alias_data.hash_stable(hcx, hasher);
+            }
             EntryKind::Impl(ref impl_data) => {
                 impl_data.hash_stable(hcx, hasher);
             }
@@ -474,6 +478,15 @@ impl_stable_hash_for!(struct TraitData<'tcx> {
     super_predicates
 });
 
+#[derive(RustcEncodable, RustcDecodable)]
+pub struct TraitAliasData<'tcx> {
+    pub super_predicates: Lazy<ty::GenericPredicates<'tcx>>,
+}
+
+impl_stable_hash_for!(struct TraitAliasData<'tcx> {
+    super_predicates
+});
+
 #[derive(RustcEncodable, RustcDecodable)]
 pub struct ImplData<'tcx> {
     pub polarity: hir::ImplPolarity,
@@ -505,7 +518,7 @@ pub enum AssociatedContainer {
     ImplFinal,
 }
 
-impl_stable_hash_for!(enum ::schema::AssociatedContainer {
+impl_stable_hash_for!(enum crate::schema::AssociatedContainer {
     TraitRequired,
     TraitWithDefault,
     ImplDefault,
diff --git a/src/librustc_mir/Cargo.toml b/src/librustc_mir/Cargo.toml
index f0234c48c3eca..c32bafa99205f 100644
--- a/src/librustc_mir/Cargo.toml
+++ b/src/librustc_mir/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_mir"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_mir"
@@ -10,9 +11,8 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
-bitflags = "1.0"
 either = "1.5.0"
-graphviz = { path = "../libgraphviz" }
+dot = { path = "../libgraphviz", package = "graphviz" }
 log = "0.4"
 log_settings = "0.1.1"
 polonius-engine = "0.6.2"
diff --git a/src/librustc_mir/borrow_check/borrow_set.rs b/src/librustc_mir/borrow_check/borrow_set.rs
index ecbc6118bc37c..53e4ffc8bd6e7 100644
--- a/src/librustc_mir/borrow_check/borrow_set.rs
+++ b/src/librustc_mir/borrow_check/borrow_set.rs
@@ -1,7 +1,7 @@
-use borrow_check::place_ext::PlaceExt;
-use borrow_check::nll::ToRegionVid;
-use dataflow::indexes::BorrowIndex;
-use dataflow::move_paths::MoveData;
+use crate::borrow_check::place_ext::PlaceExt;
+use crate::borrow_check::nll::ToRegionVid;
+use crate::dataflow::indexes::BorrowIndex;
+use crate::dataflow::move_paths::MoveData;
 use rustc::mir::traversal;
 use rustc::mir::visit::{
     PlaceContext, Visitor, NonUseContext, MutatingUseContext, NonMutatingUseContext
@@ -26,12 +26,12 @@ crate struct BorrowSet<'tcx> {
     crate location_map: FxHashMap<Location, BorrowIndex>,
 
     /// Locations which activate borrows.
-    /// NOTE: A given location may activate more than one borrow in the future
+    /// NOTE: a given location may activate more than one borrow in the future
     /// when more general two-phase borrow support is introduced, but for now we
-    /// only need to store one borrow index
+    /// only need to store one borrow index.
     crate activation_map: FxHashMap<Location, Vec<BorrowIndex>>,
 
-    /// Map from local to all the borrows on that local
+    /// Map from local to all the borrows on that local.
     crate local_map: FxHashMap<mir::Local, FxHashSet<BorrowIndex>>,
 
     crate locals_state_at_exit: LocalsStateAtExit,
@@ -45,8 +45,8 @@ impl<'tcx> Index<BorrowIndex> for BorrowSet<'tcx> {
     }
 }
 
-/// Location where a two phase borrow is activated, if a borrow
-/// is in fact a two phase borrow.
+/// Location where a two-phase borrow is activated, if a borrow
+/// is in fact a two-phase borrow.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 crate enum TwoPhaseActivation {
     NotTwoPhase,
@@ -72,7 +72,7 @@ crate struct BorrowData<'tcx> {
 }
 
 impl<'tcx> fmt::Display for BorrowData<'tcx> {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         let kind = match self.kind {
             mir::BorrowKind::Shared => "",
             mir::BorrowKind::Shallow => "shallow ",
@@ -311,7 +311,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'tcx> for GatherBorrows<'a, 'gcx, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> GatherBorrows<'a, 'gcx, 'tcx> {
-    /// Returns true if the borrow represented by `kind` is
+    /// Returns `true` if the borrow represented by `kind` is
     /// allowed to be split into separate Reservation and
     /// Activation phases.
     fn allow_two_phase_borrow(&self, kind: mir::BorrowKind) -> bool {
diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
index 233db12b03001..4d65862375a96 100644
--- a/src/librustc_mir/borrow_check/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -1,7 +1,7 @@
-use borrow_check::nll::explain_borrow::BorrowExplanation;
-use borrow_check::nll::region_infer::{RegionName, RegionNameSource};
-use borrow_check::prefixes::IsPrefixOf;
-use borrow_check::WriteKind;
+use crate::borrow_check::nll::explain_borrow::BorrowExplanation;
+use crate::borrow_check::nll::region_infer::{RegionName, RegionNameSource};
+use crate::borrow_check::prefixes::IsPrefixOf;
+use crate::borrow_check::WriteKind;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
 use rustc::middle::region::ScopeTree;
@@ -22,10 +22,10 @@ use syntax_pos::Span;
 use super::borrow_set::BorrowData;
 use super::{Context, MirBorrowckCtxt};
 use super::{InitializationRequiringAction, PrefixSet};
-use dataflow::drop_flag_effects;
-use dataflow::move_paths::indexes::MoveOutIndex;
-use dataflow::move_paths::MovePathIndex;
-use util::borrowck_errors::{BorrowckErrors, Origin};
+use crate::dataflow::drop_flag_effects;
+use crate::dataflow::move_paths::indexes::MoveOutIndex;
+use crate::dataflow::move_paths::MovePathIndex;
+use crate::util::borrowck_errors::{BorrowckErrors, Origin};
 
 #[derive(Debug)]
 struct MoveSite {
@@ -33,7 +33,7 @@ struct MoveSite {
     /// then tell us where the move occurred.
     moi: MoveOutIndex,
 
-    /// True if we traversed a back edge while walking from the point
+    /// `true` if we traversed a back edge while walking from the point
     /// of error to the move site.
     traversed_back_edge: bool
 }
@@ -198,19 +198,38 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 let place = &self.move_data.move_paths[mpi].place;
 
                 let ty = place.ty(self.mir, self.infcx.tcx).to_ty(self.infcx.tcx);
-                let note_msg = match self.describe_place_with_options(
-                    place,
-                    IncludingDowncast(true),
-                ) {
-                    Some(name) => format!("`{}`", name),
+                let opt_name = self.describe_place_with_options(place, IncludingDowncast(true));
+                let note_msg = match opt_name {
+                    Some(ref name) => format!("`{}`", name),
                     None => "value".to_owned(),
                 };
-
-                err.note(&format!(
-                    "move occurs because {} has type `{}`, \
-                     which does not implement the `Copy` trait",
-                    note_msg, ty
-                ));
+                if let ty::TyKind::Param(param_ty) = ty.sty {
+                    let tcx = self.infcx.tcx;
+                    let generics = tcx.generics_of(self.mir_def_id);
+                    let def_id = generics.type_param(&param_ty, tcx).def_id;
+                    if let Some(sp) = tcx.hir().span_if_local(def_id) {
+                        err.span_label(
+                            sp,
+                            "consider adding a `Copy` constraint to this type argument",
+                        );
+                    }
+                }
+                if let Place::Local(local) = place {
+                    let decl = &self.mir.local_decls[*local];
+                    err.span_label(
+                        decl.source_info.span,
+                        format!(
+                            "move occurs because {} has type `{}`, \
+                                which does not implement the `Copy` trait",
+                            note_msg, ty,
+                    ));
+                } else {
+                    err.note(&format!(
+                        "move occurs because {} has type `{}`, \
+                         which does not implement the `Copy` trait",
+                        note_msg, ty
+                    ));
+                }
             }
 
             if let Some((_, mut old_err)) = self.move_error_reported
@@ -814,13 +833,13 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 format!("`{}` would have to be valid for `{}`...", name, region_name),
             );
 
-            if let Some(fn_node_id) = self.infcx.tcx.hir().as_local_node_id(self.mir_def_id) {
+            if let Some(fn_hir_id) = self.infcx.tcx.hir().as_local_hir_id(self.mir_def_id) {
                 err.span_label(
                     drop_span,
                     format!(
                         "...but `{}` will be dropped here, when the function `{}` returns",
                         name,
-                        self.infcx.tcx.hir().name(fn_node_id),
+                        self.infcx.tcx.hir().name_by_hir_id(fn_hir_id),
                     ),
                 );
 
@@ -1120,7 +1139,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             Err(_) => "move |<args>| <body>".to_string()
         };
 
-        err.span_suggestion_with_applicability(
+        err.span_suggestion(
             args_span,
             &format!("to force the closure to take ownership of {} (and any \
                       other referenced variables), use the `move` keyword",
@@ -1159,7 +1178,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         let escapes_from = if tcx.is_closure(self.mir_def_id) {
             let tables = tcx.typeck_tables_of(self.mir_def_id);
             let mir_hir_id = tcx.hir().def_index_to_hir_id(self.mir_def_id.index);
-            match tables.node_id_to_type(mir_hir_id).sty {
+            match tables.node_type(mir_hir_id).sty {
                 ty::Closure(..) => "closure",
                 ty::Generator(..) => "generator",
                 _ => bug!("Closure body doesn't have a closure or generator type"),
@@ -1409,7 +1428,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         if let Some(decl) = local_decl {
             if let Some(name) = decl.name {
                 if decl.can_be_made_mutable() {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         decl.source_info.span,
                         "make this binding mutable",
                         format!("mut {}", name),
@@ -1707,7 +1726,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     }
 
     /// End-user visible description of the `field`nth field of `base`
-    fn describe_field(&self, base: &Place, field: Field) -> String {
+    fn describe_field(&self, base: &Place<'_>, field: Field) -> String {
         match *base {
             Place::Local(local) => {
                 let local = &self.mir.local_decls[local];
@@ -1732,7 +1751,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     }
 
     /// End-user visible description of the `field_index`nth field of `ty`
-    fn describe_field_from_ty(&self, ty: &ty::Ty, field: Field) -> String {
+    fn describe_field_from_ty(&self, ty: &ty::Ty<'_>, field: Field) -> String {
         if ty.is_box() {
             // If the type is a box, the field is described from the boxed type
             self.describe_field_from_ty(&ty.boxed_ty(), field)
@@ -1774,7 +1793,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         }
     }
 
-    /// Check if a place is a thread-local static.
+    /// Checks if a place is a thread-local static.
     pub fn is_place_thread_local(&self, place: &Place<'tcx>) -> bool {
         if let Place::Static(statik) = place {
             let attrs = self.infcx.tcx.get_attrs(statik.def_id);
@@ -1841,7 +1860,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     fn annotate_argument_and_return_for_borrow(
         &self,
         borrow: &BorrowData<'tcx>,
-    ) -> Option<AnnotatedBorrowFnSignature> {
+    ) -> Option<AnnotatedBorrowFnSignature<'_>> {
         // Define a fallback for when we can't match a closure.
         let fallback = || {
             let is_closure = self.infcx.tcx.is_closure(self.mir_def_id);
@@ -2062,7 +2081,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         &self,
         did: DefId,
         sig: ty::PolyFnSig<'tcx>,
-    ) -> Option<AnnotatedBorrowFnSignature> {
+    ) -> Option<AnnotatedBorrowFnSignature<'_>> {
         debug!("annotate_fn_sig: did={:?} sig={:?}", did, sig);
         let is_closure = self.infcx.tcx.is_closure(did);
         let fn_node_id = self.infcx.tcx.hir().as_local_node_id(did)?;
@@ -2295,7 +2314,7 @@ impl<'tcx> AnnotatedBorrowFnSignature<'tcx> {
         }
     }
 
-    /// Return the name of the provided `Ty` (that must be a reference)'s region with a
+    /// Returns the name of the provided `Ty` (that must be a reference)'s region with a
     /// synthesized lifetime name where required.
     fn get_region_name_for_ty(&self, ty: ty::Ty<'tcx>, counter: usize) -> String {
         match ty.sty {
@@ -2349,20 +2368,28 @@ impl UseSpans {
     }
 
     // Add a span label to the arguments of the closure, if it exists.
-    pub(super) fn args_span_label(self, err: &mut DiagnosticBuilder, message: impl Into<String>) {
+    pub(super) fn args_span_label(
+        self,
+        err: &mut DiagnosticBuilder<'_>,
+        message: impl Into<String>,
+    ) {
         if let UseSpans::ClosureUse { args_span, .. } = self {
             err.span_label(args_span, message);
         }
     }
 
     // Add a span label to the use of the captured variable, if it exists.
-    pub(super) fn var_span_label(self, err: &mut DiagnosticBuilder, message: impl Into<String>) {
+    pub(super) fn var_span_label(
+        self,
+        err: &mut DiagnosticBuilder<'_>,
+        message: impl Into<String>,
+    ) {
         if let UseSpans::ClosureUse { var_span, .. } = self {
             err.span_label(var_span, message);
         }
     }
 
-    /// Return `false` if this place is not used in a closure.
+    /// Returns `false` if this place is not used in a closure.
     fn for_closure(&self) -> bool {
         match *self {
             UseSpans::ClosureUse { is_generator, .. } => !is_generator,
@@ -2370,7 +2397,7 @@ impl UseSpans {
         }
     }
 
-    /// Return `false` if this place is not used in a generator.
+    /// Returns `false` if this place is not used in a generator.
     fn for_generator(&self) -> bool {
         match *self {
             UseSpans::ClosureUse { is_generator, .. } => is_generator,
@@ -2544,7 +2571,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
 
     /// Helper to retrieve span(s) of given borrow from the current MIR
     /// representation
-    pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData) -> UseSpans {
+    pub(super) fn retrieve_borrow_spans(&self, borrow: &BorrowData<'_>) -> UseSpans {
         let span = self.mir.source_info(borrow.reserve_location).span;
         self.borrow_spans(span, borrow.reserve_location)
     }
diff --git a/src/librustc_mir/borrow_check/flows.rs b/src/librustc_mir/borrow_check/flows.rs
index 4eeb19c4e7a67..8de39f0efc1a5 100644
--- a/src/librustc_mir/borrow_check/flows.rs
+++ b/src/librustc_mir/borrow_check/flows.rs
@@ -7,16 +7,16 @@ use rustc::mir::{BasicBlock, Location};
 use rustc::ty::RegionVid;
 use rustc_data_structures::bit_set::BitIter;
 
-use borrow_check::location::LocationIndex;
+use crate::borrow_check::location::LocationIndex;
 
 use polonius_engine::Output;
 
-use dataflow::move_paths::indexes::BorrowIndex;
-use dataflow::move_paths::HasMoveData;
-use dataflow::Borrows;
-use dataflow::EverInitializedPlaces;
-use dataflow::{FlowAtLocation, FlowsAtLocation};
-use dataflow::MaybeUninitializedPlaces;
+use crate::dataflow::move_paths::indexes::BorrowIndex;
+use crate::dataflow::move_paths::HasMoveData;
+use crate::dataflow::Borrows;
+use crate::dataflow::EverInitializedPlaces;
+use crate::dataflow::{FlowAtLocation, FlowsAtLocation};
+use crate::dataflow::MaybeUninitializedPlaces;
 use either::Either;
 use std::fmt;
 use std::rc::Rc;
@@ -57,7 +57,7 @@ impl<'b, 'gcx, 'tcx> Flows<'b, 'gcx, 'tcx> {
         }
     }
 
-    crate fn with_outgoing_borrows(&self, op: impl FnOnce(BitIter<BorrowIndex>)) {
+    crate fn with_outgoing_borrows(&self, op: impl FnOnce(BitIter<'_, BorrowIndex>)) {
         self.borrows.with_iter_outgoing(op)
     }
 }
@@ -93,7 +93,7 @@ impl<'b, 'gcx, 'tcx> FlowsAtLocation for Flows<'b, 'gcx, 'tcx> {
 }
 
 impl<'b, 'gcx, 'tcx> fmt::Display for Flows<'b, 'gcx, 'tcx> {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut s = String::new();
 
         s.push_str("borrows in effect: [");
diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 45632245b61de..f7d079c5494ef 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -1,6 +1,6 @@
 //! This query borrow-checks the MIR to (further) ensure it is not broken.
 
-use borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::nll::region_infer::RegionInferenceContext;
 use rustc::hir;
 use rustc::hir::Node;
 use rustc::hir::def_id::DefId;
@@ -25,16 +25,16 @@ use std::collections::BTreeMap;
 
 use syntax_pos::Span;
 
-use dataflow::indexes::{BorrowIndex, InitIndex, MoveOutIndex, MovePathIndex};
-use dataflow::move_paths::{HasMoveData, LookupResult, MoveData, MoveError};
-use dataflow::Borrows;
-use dataflow::DataflowResultsConsumer;
-use dataflow::FlowAtLocation;
-use dataflow::MoveDataParamEnv;
-use dataflow::{do_dataflow, DebugFormatted};
-use dataflow::EverInitializedPlaces;
-use dataflow::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
-use util::borrowck_errors::{BorrowckErrors, Origin};
+use crate::dataflow::indexes::{BorrowIndex, InitIndex, MoveOutIndex, MovePathIndex};
+use crate::dataflow::move_paths::{HasMoveData, LookupResult, MoveData, MoveError};
+use crate::dataflow::Borrows;
+use crate::dataflow::DataflowResultsConsumer;
+use crate::dataflow::FlowAtLocation;
+use crate::dataflow::MoveDataParamEnv;
+use crate::dataflow::{do_dataflow, DebugFormatted};
+use crate::dataflow::EverInitializedPlaces;
+use crate::dataflow::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
+use crate::util::borrowck_errors::{BorrowckErrors, Origin};
 
 use self::borrow_set::{BorrowData, BorrowSet};
 use self::flows::Flows;
@@ -59,7 +59,7 @@ mod used_muts;
 
 pub(crate) mod nll;
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         mir_borrowck,
         ..*providers
@@ -108,7 +108,7 @@ fn mir_borrowck<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> BorrowC
     }
 
     let opt_closure_req = tcx.infer_ctxt().enter(|infcx| {
-        let input_mir: &Mir = &input_mir.borrow();
+        let input_mir: &Mir<'_> = &input_mir.borrow();
         do_mir_borrowck(&infcx, input_mir, def_id)
     });
     debug!("mir_borrowck done");
@@ -163,10 +163,7 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
         |bd, i| DebugFormatted::new(&bd.move_data().move_paths[i]),
     ));
 
-    let locals_are_invalidated_at_exit = match tcx.hir().body_owner_kind(id) {
-            hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => false,
-            hir::BodyOwnerKind::Fn => true,
-    };
+    let locals_are_invalidated_at_exit = tcx.hir().body_owner_kind(id).is_fn_or_closure();
     let borrow_set = Rc::new(BorrowSet::build(
             tcx, mir, locals_are_invalidated_at_exit, &mdpe.move_data));
 
@@ -310,7 +307,7 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
                 span,
                 "variable does not need to be mutable",
             )
-            .span_suggestion_short_with_applicability(
+            .span_suggestion_short(
                 mut_span,
                 "remove this `mut`",
                 String::new(),
@@ -423,11 +420,11 @@ pub struct MirBorrowckCtxt<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
     access_place_error_reported: FxHashSet<(Place<'tcx>, Span)>,
     /// This field keeps track of when borrow conflict errors are reported
     /// for reservations, so that we don't report seemingly duplicate
-    /// errors for corresponding activations
-    ///
-    /// FIXME: Ideally this would be a set of BorrowIndex, not Places,
-    /// but it is currently inconvenient to track down the BorrowIndex
-    /// at the time we detect and report a reservation error.
+    /// errors for corresponding activations.
+    //
+    // FIXME: ideally this would be a set of `BorrowIndex`, not `Place`s,
+    // but it is currently inconvenient to track down the `BorrowIndex`
+    // at the time we detect and report a reservation error.
     reservation_error_reported: FxHashSet<Place<'tcx>>,
     /// This field keeps track of move errors that are to be reported for given move indicies.
     ///
@@ -455,7 +452,7 @@ pub struct MirBorrowckCtxt<'cx, 'gcx: 'tcx, 'tcx: 'cx> {
     /// If the function we're checking is a closure, then we'll need to report back the list of
     /// mutable upvars that have been used. This field keeps track of them.
     used_mut_upvars: SmallVec<[Field; 8]>,
-    /// Non-lexical region inference context, if NLL is enabled.  This
+    /// Non-lexical region inference context, if NLL is enabled. This
     /// contains the results from region inference and lets us e.g.
     /// find out which CFG points are contained in each borrow region.
     nonlexical_regioncx: Rc<RegionInferenceContext<'tcx>>,
@@ -838,12 +835,12 @@ enum WriteKind {
 
 /// When checking permissions for a place access, this flag is used to indicate that an immutable
 /// local place can be mutated.
-///
-/// FIXME: @nikomatsakis suggested that this flag could be removed with the following modifications:
-/// - Merge `check_access_permissions()` and `check_if_reassignment_to_immutable_state()`
-/// - Split `is_mutable()` into `is_assignable()` (can be directly assigned) and
-///   `is_declared_mutable()`
-/// - Take flow state into consideration in `is_assignable()` for local variables
+//
+// FIXME: @nikomatsakis suggested that this flag could be removed with the following modifications:
+// - Merge `check_access_permissions()` and `check_if_reassignment_to_immutable_state()`.
+// - Split `is_mutable()` into `is_assignable()` (can be directly assigned) and
+//   `is_declared_mutable()`.
+// - Take flow state into consideration in `is_assignable()` for local variables.
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 enum LocalMutationIsAllowed {
     Yes,
@@ -898,7 +895,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     /// place is initialized and (b) it is not borrowed in some way that would prevent this
     /// access.
     ///
-    /// Returns true if an error is reported, false otherwise.
+    /// Returns `true` if an error is reported.
     fn access_place(
         &mut self,
         context: Context,
@@ -1788,9 +1785,9 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         }
     }
 
-    /// Check the permissions for the given place and read or write kind
+    /// Checks the permissions for the given place and read or write kind
     ///
-    /// Returns true if an error is reported, false otherwise.
+    /// Returns `true` if an error is reported.
     fn check_access_permissions(
         &mut self,
         (place, span): (&Place<'tcx>, Span),
diff --git a/src/librustc_mir/borrow_check/move_errors.rs b/src/librustc_mir/borrow_check/move_errors.rs
index 3c62614ce4766..2a5433d431786 100644
--- a/src/librustc_mir/borrow_check/move_errors.rs
+++ b/src/librustc_mir/borrow_check/move_errors.rs
@@ -6,13 +6,13 @@ use rustc::ty;
 use rustc_errors::{DiagnosticBuilder,Applicability};
 use syntax_pos::Span;
 
-use borrow_check::MirBorrowckCtxt;
-use borrow_check::prefixes::PrefixSet;
-use dataflow::move_paths::{
+use crate::borrow_check::MirBorrowckCtxt;
+use crate::borrow_check::prefixes::PrefixSet;
+use crate::dataflow::move_paths::{
     IllegalMoveOrigin, IllegalMoveOriginKind, InitLocation,
     LookupResult, MoveError, MovePathIndex,
 };
-use util::borrowck_errors::{BorrowckErrors, Origin};
+use crate::util::borrowck_errors::{BorrowckErrors, Origin};
 
 // Often when desugaring a pattern match we may have many individual moves in
 // MIR that are all part of one operation from the user's point-of-view. For
@@ -63,7 +63,7 @@ enum BorrowedContentSource {
 }
 
 impl Display for BorrowedContentSource {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             BorrowedContentSource::Arc => write!(f, "an `Arc`"),
             BorrowedContentSource::Rc => write!(f, "an `Rc`"),
@@ -240,7 +240,7 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
 
     fn report(&mut self, error: GroupedMoveError<'tcx>) {
         let (mut err, err_span) = {
-            let (span, original_path, kind): (Span, &Place<'tcx>, &IllegalMoveOriginKind) =
+            let (span, original_path, kind): (Span, &Place<'tcx>, &IllegalMoveOriginKind<'_>) =
                 match error {
                     GroupedMoveError::MovesFromPlace {
                         span,
@@ -308,9 +308,8 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                                         let upvar_decl = &self.mir.upvar_decls[field.index()];
                                         let upvar_hir_id =
                                             upvar_decl.var_hir_id.assert_crate_local();
-                                        let upvar_node_id =
-                                            self.infcx.tcx.hir().hir_to_node_id(upvar_hir_id);
-                                        let upvar_span = self.infcx.tcx.hir().span(upvar_node_id);
+                                        let upvar_span = self.infcx.tcx.hir().span_by_hir_id(
+                                            upvar_hir_id);
                                         diag.span_label(upvar_span, "captured outer variable");
                                         break;
                                     }
@@ -368,14 +367,14 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                     // expressions `a[b]`, which roughly desugar to
                     // `*Index::index(&a, b)` or
                     // `*IndexMut::index_mut(&mut a, b)`.
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "consider removing the `*`",
                         snippet[1..].to_owned(),
                         Applicability::Unspecified,
                     );
                 } else {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "consider borrowing here",
                         format!("&{}", snippet),
@@ -439,7 +438,7 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
         suggestions.sort_unstable_by_key(|&(span, _, _)| span);
         suggestions.dedup_by_key(|&mut (span, _, _)| span);
         for (span, to_remove, suggestion) in suggestions {
-            err.span_suggestion_with_applicability(
+            err.span_suggestion(
                 span,
                 &format!("consider removing the `{}`", to_remove),
                 suggestion,
diff --git a/src/librustc_mir/borrow_check/mutability_errors.rs b/src/librustc_mir/borrow_check/mutability_errors.rs
index 63bf6faed40d4..008c081aeb601 100644
--- a/src/librustc_mir/borrow_check/mutability_errors.rs
+++ b/src/librustc_mir/borrow_check/mutability_errors.rs
@@ -8,11 +8,11 @@ use rustc_data_structures::indexed_vec::Idx;
 use syntax_pos::Span;
 use syntax_pos::symbol::keywords;
 
-use dataflow::move_paths::InitLocation;
-use borrow_check::MirBorrowckCtxt;
-use util::borrowck_errors::{BorrowckErrors, Origin};
-use util::collect_writes::FindAssignments;
-use util::suggest_ref_mut;
+use crate::dataflow::move_paths::InitLocation;
+use crate::borrow_check::MirBorrowckCtxt;
+use crate::util::borrowck_errors::{BorrowckErrors, Origin};
+use crate::util::collect_writes::FindAssignments;
+use crate::util::suggest_ref_mut;
 use rustc_errors::Applicability;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -231,7 +231,7 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                     base.ty(self.mir, self.infcx.tcx).to_ty(self.infcx.tcx),
                     field,
                 ) {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "consider changing this to be mutable",
                         message,
@@ -285,7 +285,7 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                 assert_eq!(local_decl.mutability, Mutability::Not);
 
                 err.span_label(span, format!("cannot {ACT}", ACT = act));
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     local_decl.source_info.span,
                     "consider changing this to be mutable",
                     format!("mut {}", local_decl.name.unwrap()),
@@ -312,11 +312,12 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                     if let hir::PatKind::Binding(
                         hir::BindingAnnotation::Unannotated,
                         _,
+                        _,
                         upvar_ident,
                         _,
                     ) = pat.node
                     {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             upvar_ident.span,
                             "consider changing this to be mutable",
                             format!("mut {}", upvar_ident.name),
@@ -410,7 +411,7 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
                 };
 
                 if let Some((err_help_span, suggested_code)) = suggestion {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         err_help_span,
                         &format!("consider changing this to be a mutable {}", pointer_desc),
                         suggested_code,
@@ -610,11 +611,11 @@ fn suggest_ampmut<'cx, 'gcx, 'tcx>(
      })
 }
 
-fn is_closure_or_generator(ty: ty::Ty) -> bool {
+fn is_closure_or_generator(ty: ty::Ty<'_>) -> bool {
     ty.is_closure() || ty.is_generator()
 }
 
-/// Add a suggestion to a struct definition given a field access to a local.
+/// Adds a suggestion to a struct definition given a field access to a local.
 /// This function expects the local to be a reference to a struct in order to produce a suggestion.
 ///
 /// ```text
diff --git a/src/librustc_mir/borrow_check/nll/constraint_generation.rs b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
index e1c2b611d0117..c02c2b4934cf4 100644
--- a/src/librustc_mir/borrow_check/nll/constraint_generation.rs
+++ b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
@@ -1,13 +1,13 @@
-use borrow_check::borrow_set::BorrowSet;
-use borrow_check::location::LocationTable;
-use borrow_check::nll::ToRegionVid;
-use borrow_check::nll::facts::AllFacts;
-use borrow_check::nll::region_infer::values::LivenessValues;
+use crate::borrow_check::borrow_set::BorrowSet;
+use crate::borrow_check::location::LocationTable;
+use crate::borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::facts::AllFacts;
+use crate::borrow_check::nll::region_infer::values::LivenessValues;
 use rustc::infer::InferCtxt;
 use rustc::mir::visit::TyContext;
 use rustc::mir::visit::Visitor;
 use rustc::mir::{BasicBlock, BasicBlockData, Location, Mir, Place, Rvalue};
-use rustc::mir::{Statement, Terminator};
+use rustc::mir::{SourceInfo, Statement, Terminator};
 use rustc::mir::UserTypeProjection;
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::subst::Substs;
@@ -66,11 +66,12 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
     /// call. Make them live at the location where they appear.
     fn visit_ty(&mut self, ty: &ty::Ty<'tcx>, ty_context: TyContext) {
         match ty_context {
-            TyContext::ReturnTy(source_info)
-            | TyContext::YieldTy(source_info)
-            | TyContext::LocalDecl { source_info, .. } => {
+            TyContext::ReturnTy(SourceInfo { span, .. })
+            | TyContext::YieldTy(SourceInfo { span, .. })
+            | TyContext::UserTy(span)
+            | TyContext::LocalDecl { source_info: SourceInfo { span, .. }, .. } => {
                 span_bug!(
-                    source_info.span,
+                    span,
                     "should not be visiting outside of the CFG: {:?}",
                     ty_context
                 );
diff --git a/src/librustc_mir/borrow_check/nll/constraints/graph.rs b/src/librustc_mir/borrow_check/nll/constraints/graph.rs
index fe9ccb489e425..c4b2a5daef89a 100644
--- a/src/librustc_mir/borrow_check/nll/constraints/graph.rs
+++ b/src/librustc_mir/borrow_check/nll/constraints/graph.rs
@@ -1,6 +1,6 @@
-use borrow_check::nll::type_check::Locations;
-use borrow_check::nll::constraints::ConstraintIndex;
-use borrow_check::nll::constraints::{ConstraintSet, OutlivesConstraint};
+use crate::borrow_check::nll::type_check::Locations;
+use crate::borrow_check::nll::constraints::ConstraintIndex;
+use crate::borrow_check::nll::constraints::{ConstraintSet, OutlivesConstraint};
 use rustc::mir::ConstraintCategory;
 use rustc::ty::RegionVid;
 use rustc_data_structures::graph;
@@ -71,7 +71,7 @@ impl ConstraintGraphDirecton for Reverse {
 }
 
 impl<D: ConstraintGraphDirecton> ConstraintGraph<D> {
-    /// Create a "dependency graph" where each region constraint `R1:
+    /// Creates a "dependency graph" where each region constraint `R1:
     /// R2` is treated as an edge `R1 -> R2`. We use this graph to
     /// construct SCCs for region inference but also for error
     /// reporting.
@@ -186,7 +186,7 @@ crate struct RegionGraph<'s, D: ConstraintGraphDirecton> {
 }
 
 impl<'s, D: ConstraintGraphDirecton> RegionGraph<'s, D> {
-    /// Create a "dependency graph" where each region constraint `R1:
+    /// Creates a "dependency graph" where each region constraint `R1:
     /// R2` is treated as an edge `R1 -> R2`. We use this graph to
     /// construct SCCs for region inference but also for error
     /// reporting.
diff --git a/src/librustc_mir/borrow_check/nll/constraints/mod.rs b/src/librustc_mir/borrow_check/nll/constraints/mod.rs
index 146bd65dd1143..b1091eb5ac81f 100644
--- a/src/librustc_mir/borrow_check/nll/constraints/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/constraints/mod.rs
@@ -2,7 +2,7 @@ use rustc::mir::ConstraintCategory;
 use rustc::ty::RegionVid;
 use rustc_data_structures::graph::scc::Sccs;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
-use borrow_check::nll::type_check::Locations;
+use crate::borrow_check::nll::type_check::Locations;
 
 use std::fmt;
 use std::ops::Deref;
@@ -31,7 +31,7 @@ impl ConstraintSet {
     /// easy to find the constraints affecting a particular region.
     ///
     /// N.B., this graph contains a "frozen" view of the current
-    /// constraints.  any new constraints added to the `ConstraintSet`
+    /// constraints. Any new constraints added to the `ConstraintSet`
     /// after the graph is built will not be present in the graph.
     crate fn graph(&self, num_region_vars: usize) -> graph::NormalConstraintGraph {
         graph::ConstraintGraph::new(graph::Normal, self, num_region_vars)
@@ -43,7 +43,7 @@ impl ConstraintSet {
         graph::ConstraintGraph::new(graph::Reverse, self, num_region_vars)
     }
 
-    /// Compute cycles (SCCs) in the graph of regions. In particular,
+    /// Computes cycles (SCCs) in the graph of regions. In particular,
     /// find all regions R1, R2 such that R1: R2 and R2: R1 and group
     /// them into an SCC, and find the relationships between SCCs.
     crate fn compute_sccs(
@@ -84,7 +84,7 @@ pub struct OutlivesConstraint {
 }
 
 impl fmt::Debug for OutlivesConstraint {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             formatter,
             "({:?}: {:?}) due to {:?}",
diff --git a/src/librustc_mir/borrow_check/nll/explain_borrow/find_use.rs b/src/librustc_mir/borrow_check/nll/explain_borrow/find_use.rs
index 53035dae4f35c..7d6385752c348 100644
--- a/src/librustc_mir/borrow_check/nll/explain_borrow/find_use.rs
+++ b/src/librustc_mir/borrow_check/nll/explain_borrow/find_use.rs
@@ -1,13 +1,13 @@
 use std::collections::VecDeque;
 use std::rc::Rc;
 
-use borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
-use borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::region_infer::{Cause, RegionInferenceContext};
+use crate::borrow_check::nll::ToRegionVid;
+use crate::util::liveness::{self, DefUse};
 use rustc::mir::visit::{MirVisitable, PlaceContext, Visitor};
 use rustc::mir::{Local, Location, Mir};
 use rustc::ty::{RegionVid, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
-use util::liveness::{self, DefUse};
 
 crate fn find<'tcx>(
     mir: &Mir<'tcx>,
@@ -65,10 +65,7 @@ impl<'cx, 'gcx, 'tcx> UseFinder<'cx, 'gcx, 'tcx> {
 
                 None => {
                     if p.statement_index < block_data.statements.len() {
-                        queue.push_back(Location {
-                            statement_index: p.statement_index + 1,
-                            ..p
-                        });
+                        queue.push_back(p.successor_within_block());
                     } else {
                         queue.extend(
                             block_data
diff --git a/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs b/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
index 968c0f53a4852..8ea249959dd2c 100644
--- a/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/explain_borrow/mod.rs
@@ -1,20 +1,22 @@
-use borrow_check::borrow_set::BorrowData;
-use borrow_check::error_reporting::UseSpans;
-use borrow_check::nll::ConstraintDescription;
-use borrow_check::nll::region_infer::{Cause, RegionName};
-use borrow_check::{Context, MirBorrowckCtxt, WriteKind};
-use rustc::ty::{self, TyCtxt};
+use std::collections::VecDeque;
+
+use crate::borrow_check::borrow_set::BorrowData;
+use crate::borrow_check::error_reporting::UseSpans;
+use crate::borrow_check::nll::region_infer::{Cause, RegionName};
+use crate::borrow_check::nll::ConstraintDescription;
+use crate::borrow_check::{Context, MirBorrowckCtxt, WriteKind};
 use rustc::mir::{
-    CastKind, ConstraintCategory, FakeReadCause, Local, Location, Mir, Operand,
-    Place, Projection, ProjectionElem, Rvalue, Statement, StatementKind,
-    TerminatorKind
+    CastKind, ConstraintCategory, FakeReadCause, Local, Location, Mir, Operand, Place, Projection,
+    ProjectionElem, Rvalue, Statement, StatementKind, TerminatorKind,
 };
+use rustc::ty::{self, TyCtxt};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::DiagnosticBuilder;
 use syntax_pos::Span;
 
 mod find_use;
 
-pub(in borrow_check) enum BorrowExplanation {
+pub(in crate::borrow_check) enum BorrowExplanation {
     UsedLater(LaterUseKind, Span),
     UsedLaterInLoop(LaterUseKind, Span),
     UsedLaterWhenDropped {
@@ -33,7 +35,7 @@ pub(in borrow_check) enum BorrowExplanation {
 }
 
 #[derive(Clone, Copy)]
-pub(in borrow_check) enum LaterUseKind {
+pub(in crate::borrow_check) enum LaterUseKind {
     TraitCapture,
     ClosureCapture,
     Call,
@@ -42,13 +44,13 @@ pub(in borrow_check) enum LaterUseKind {
 }
 
 impl BorrowExplanation {
-    pub(in borrow_check) fn is_explained(&self) -> bool {
+    pub(in crate::borrow_check) fn is_explained(&self) -> bool {
         match self {
             BorrowExplanation::Unexplained => false,
             _ => true,
         }
     }
-    pub(in borrow_check) fn add_explanation_to_diagnostic<'cx, 'gcx, 'tcx>(
+    pub(in crate::borrow_check) fn add_explanation_to_diagnostic<'cx, 'gcx, 'tcx>(
         &self,
         tcx: TyCtxt<'cx, 'gcx, 'tcx>,
         mir: &Mir<'tcx>,
@@ -60,50 +62,58 @@ impl BorrowExplanation {
                 let message = match later_use_kind {
                     LaterUseKind::TraitCapture => "borrow later captured here by trait object",
                     LaterUseKind::ClosureCapture => "borrow later captured here by closure",
-                    LaterUseKind::Call =>  "borrow later used by call",
+                    LaterUseKind::Call => "borrow later used by call",
                     LaterUseKind::FakeLetRead => "borrow later stored here",
                     LaterUseKind::Other => "borrow later used here",
                 };
                 err.span_label(var_or_use_span, format!("{}{}", borrow_desc, message));
-            },
+            }
             BorrowExplanation::UsedLaterInLoop(later_use_kind, var_or_use_span) => {
                 let message = match later_use_kind {
-                    LaterUseKind::TraitCapture =>
-                        "borrow captured here by trait object, in later iteration of loop",
-                    LaterUseKind::ClosureCapture =>
-                        "borrow captured here by closure, in later iteration of loop",
-                    LaterUseKind::Call =>  "borrow used by call, in later iteration of loop",
+                    LaterUseKind::TraitCapture => {
+                        "borrow captured here by trait object, in later iteration of loop"
+                    }
+                    LaterUseKind::ClosureCapture => {
+                        "borrow captured here by closure, in later iteration of loop"
+                    }
+                    LaterUseKind::Call => "borrow used by call, in later iteration of loop",
                     LaterUseKind::FakeLetRead => "borrow later stored here",
                     LaterUseKind::Other => "borrow used here, in later iteration of loop",
                 };
                 err.span_label(var_or_use_span, format!("{}{}", borrow_desc, message));
-            },
-            BorrowExplanation::UsedLaterWhenDropped { drop_loc, dropped_local,
-                                                      should_note_order } =>
-            {
+            }
+            BorrowExplanation::UsedLaterWhenDropped {
+                drop_loc,
+                dropped_local,
+                should_note_order,
+            } => {
                 let local_decl = &mir.local_decls[dropped_local];
                 let (dtor_desc, type_desc) = match local_decl.ty.sty {
                     // If type is an ADT that implements Drop, then
                     // simplify output by reporting just the ADT name.
-                    ty::Adt(adt, _substs) if adt.has_dtor(tcx) && !adt.is_box() =>
-                        ("`Drop` code", format!("type `{}`", tcx.item_path_str(adt.did))),
+                    ty::Adt(adt, _substs) if adt.has_dtor(tcx) && !adt.is_box() => (
+                        "`Drop` code",
+                        format!("type `{}`", tcx.item_path_str(adt.did)),
+                    ),
 
                     // Otherwise, just report the whole type (and use
                     // the intentionally fuzzy phrase "destructor")
-                    ty::Closure(..) =>
-                        ("destructor", "closure".to_owned()),
-                    ty::Generator(..) =>
-                        ("destructor", "generator".to_owned()),
+                    ty::Closure(..) => ("destructor", "closure".to_owned()),
+                    ty::Generator(..) => ("destructor", "generator".to_owned()),
 
                     _ => ("destructor", format!("type `{}`", local_decl.ty)),
                 };
 
                 match local_decl.name {
                     Some(local_name) => {
-                        let message =
-                            format!("{B}borrow might be used here, when `{LOC}` is dropped \
-                                     and runs the {DTOR} for {TYPE}",
-                                    B=borrow_desc, LOC=local_name, TYPE=type_desc, DTOR=dtor_desc);
+                        let message = format!(
+                            "{B}borrow might be used here, when `{LOC}` is dropped \
+                             and runs the {DTOR} for {TYPE}",
+                            B = borrow_desc,
+                            LOC = local_name,
+                            TYPE = type_desc,
+                            DTOR = dtor_desc
+                        );
                         err.span_label(mir.source_info(drop_loc).span, message);
 
                         if should_note_order {
@@ -114,15 +124,22 @@ impl BorrowExplanation {
                         }
                     }
                     None => {
-                        err.span_label(local_decl.source_info.span,
-                                       format!("a temporary with access to the {B}borrow \
-                                                is created here ...",
-                                               B=borrow_desc));
-                        let message =
-                            format!("... and the {B}borrow might be used here, \
-                                     when that temporary is dropped \
-                                     and runs the {DTOR} for {TYPE}",
-                                    B=borrow_desc, TYPE=type_desc, DTOR=dtor_desc);
+                        err.span_label(
+                            local_decl.source_info.span,
+                            format!(
+                                "a temporary with access to the {B}borrow \
+                                 is created here ...",
+                                B = borrow_desc
+                            ),
+                        );
+                        let message = format!(
+                            "... and the {B}borrow might be used here, \
+                             when that temporary is dropped \
+                             and runs the {DTOR} for {TYPE}",
+                            B = borrow_desc,
+                            TYPE = type_desc,
+                            DTOR = dtor_desc
+                        );
                         err.span_label(mir.source_info(drop_loc).span, message);
 
                         if let Some(info) = &local_decl.is_block_tail {
@@ -146,7 +163,7 @@ impl BorrowExplanation {
                         }
                     }
                 }
-            },
+            }
             BorrowExplanation::MustBeValidFor {
                 category,
                 span,
@@ -157,18 +174,28 @@ impl BorrowExplanation {
                 region_name.highlight_region_name(err);
 
                 if let Some(desc) = opt_place_desc {
-                    err.span_label(span, format!(
-                        "{}requires that `{}` is borrowed for `{}`",
-                        category.description(), desc, region_name,
-                    ));
+                    err.span_label(
+                        span,
+                        format!(
+                            "{}requires that `{}` is borrowed for `{}`",
+                            category.description(),
+                            desc,
+                            region_name,
+                        ),
+                    );
                 } else {
-                    err.span_label(span, format!(
-                        "{}requires that {}borrow lasts for `{}`",
-                        category.description(), borrow_desc, region_name,
-                    ));
+                    err.span_label(
+                        span,
+                        format!(
+                            "{}requires that {}borrow lasts for `{}`",
+                            category.description(),
+                            borrow_desc,
+                            region_name,
+                        ),
+                    );
                 };
-            },
-            _ => {},
+            }
+            _ => {}
         }
     }
 }
@@ -187,7 +214,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     ///   - second half is the place being accessed
     ///
     /// [d]: https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points
-    pub(in borrow_check) fn explain_why_borrow_contains_point(
+    pub(in crate::borrow_check) fn explain_why_borrow_contains_point(
         &self,
         context: Context,
         borrow: &BorrowData<'tcx>,
@@ -214,13 +241,15 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
             region_sub
         );
 
-         match find_use::find(mir, regioncx, tcx, region_sub, context.loc) {
+        match find_use::find(mir, regioncx, tcx, region_sub, context.loc) {
             Some(Cause::LiveVar(local, location)) => {
                 let span = mir.source_info(location).span;
-                let spans = self.move_spans(&Place::Local(local), location)
+                let spans = self
+                    .move_spans(&Place::Local(local), location)
                     .or_else(|| self.borrow_spans(span, location));
 
-                if self.is_borrow_location_in_loop(context.loc) {
+                let borrow_location = context.loc;
+                if self.is_use_in_later_iteration_of_loop(borrow_location, location) {
                     let later_use = self.later_use_kind(borrow, spans, location);
                     BorrowExplanation::UsedLaterInLoop(later_use.0, later_use.1)
                 } else {
@@ -232,155 +261,223 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 }
             }
 
-             Some(Cause::DropVar(local, location)) => {
-                 let mut should_note_order = false;
-                 if mir.local_decls[local].name.is_some() {
-                     if let Some((WriteKind::StorageDeadOrDrop, place)) = kind_place {
-                         if let Place::Local(borrowed_local) = place {
-                             let dropped_local_scope = mir.local_decls[local].visibility_scope;
-                             let borrowed_local_scope =
-                                 mir.local_decls[*borrowed_local].visibility_scope;
-
-                             if mir.is_sub_scope(borrowed_local_scope, dropped_local_scope)
-                                 && local != *borrowed_local
-                             {
-                                 should_note_order = true;
-                             }
-                         }
-                     }
-                 }
-
-                 BorrowExplanation::UsedLaterWhenDropped {
-                     drop_loc: location,
-                     dropped_local: local,
-                     should_note_order,
-                 }
+            Some(Cause::DropVar(local, location)) => {
+                let mut should_note_order = false;
+                if mir.local_decls[local].name.is_some() {
+                    if let Some((WriteKind::StorageDeadOrDrop, place)) = kind_place {
+                        if let Place::Local(borrowed_local) = place {
+                            let dropped_local_scope = mir.local_decls[local].visibility_scope;
+                            let borrowed_local_scope =
+                                mir.local_decls[*borrowed_local].visibility_scope;
+
+                            if mir.is_sub_scope(borrowed_local_scope, dropped_local_scope)
+                                && local != *borrowed_local
+                            {
+                                should_note_order = true;
+                            }
+                        }
+                    }
+                }
+
+                BorrowExplanation::UsedLaterWhenDropped {
+                    drop_loc: location,
+                    dropped_local: local,
+                    should_note_order,
+                }
             }
 
-            None => if let Some(region) = regioncx.to_error_region_vid(borrow_region_vid) {
-                let (category, from_closure, span, region_name) = self
-                    .nonlexical_regioncx
-                    .free_region_constraint_info(
-                        self.mir,
-                        self.mir_def_id,
-                        self.infcx,
-                        borrow_region_vid,
-                        region,
-                    );
-                if let Some(region_name) = region_name {
-                    let opt_place_desc = self.describe_place(&borrow.borrowed_place);
-                    BorrowExplanation::MustBeValidFor {
-                        category,
-                        from_closure,
-                        span,
-                        region_name,
-                        opt_place_desc,
+            None => {
+                if let Some(region) = regioncx.to_error_region_vid(borrow_region_vid) {
+                    let (category, from_closure, span, region_name) =
+                        self.nonlexical_regioncx.free_region_constraint_info(
+                            self.mir,
+                            self.mir_def_id,
+                            self.infcx,
+                            borrow_region_vid,
+                            region,
+                        );
+                    if let Some(region_name) = region_name {
+                        let opt_place_desc = self.describe_place(&borrow.borrowed_place);
+                        BorrowExplanation::MustBeValidFor {
+                            category,
+                            from_closure,
+                            span,
+                            region_name,
+                            opt_place_desc,
+                        }
+                    } else {
+                        BorrowExplanation::Unexplained
                     }
                 } else {
                     BorrowExplanation::Unexplained
                 }
-            } else {
-                BorrowExplanation::Unexplained
             }
         }
     }
 
-    /// Check if a borrow location is within a loop.
-    fn is_borrow_location_in_loop(
+    /// true if `borrow_location` can reach `use_location` by going through a loop and
+    /// `use_location` is also inside of that loop
+    fn is_use_in_later_iteration_of_loop(
         &self,
         borrow_location: Location,
+        use_location: Location,
     ) -> bool {
-        let mut visited_locations = Vec::new();
-        let mut pending_locations = vec![ borrow_location ];
-        debug!("is_in_loop: borrow_location={:?}", borrow_location);
-
-        while let Some(location) = pending_locations.pop() {
-            debug!("is_in_loop: location={:?} pending_locations={:?} visited_locations={:?}",
-                   location, pending_locations, visited_locations);
-            if location == borrow_location && visited_locations.contains(&borrow_location) {
-                // We've managed to return to where we started (and this isn't the start of the
-                // search).
-                debug!("is_in_loop: found!");
-                return true;
-            }
+        let back_edge = self.reach_through_backedge(borrow_location, use_location);
+        back_edge.map_or(false, |back_edge| {
+            self.can_reach_head_of_loop(use_location, back_edge)
+        })
+    }
 
-            // Skip locations we've been.
-            if visited_locations.contains(&location) { continue; }
+    /// Returns the outmost back edge if `from` location can reach `to` location passing through
+    /// that back edge
+    fn reach_through_backedge(&self, from: Location, to: Location) -> Option<Location> {
+        let mut visited_locations = FxHashSet::default();
+        let mut pending_locations = VecDeque::new();
+        visited_locations.insert(from);
+        pending_locations.push_back(from);
+        debug!("reach_through_backedge: from={:?} to={:?}", from, to,);
+
+        let mut outmost_back_edge = None;
+        while let Some(location) = pending_locations.pop_front() {
+            debug!(
+                "reach_through_backedge: location={:?} outmost_back_edge={:?}
+                   pending_locations={:?} visited_locations={:?}",
+                location, outmost_back_edge, pending_locations, visited_locations
+            );
+
+            if location == to && outmost_back_edge.is_some() {
+                // We've managed to reach the use location
+                debug!("reach_through_backedge: found!");
+                return outmost_back_edge;
+            }
 
             let block = &self.mir.basic_blocks()[location.block];
-            if location.statement_index ==  block.statements.len() {
-                // Add start location of the next blocks to pending locations.
-                match block.terminator().kind {
-                    TerminatorKind::Goto { target } => {
-                        pending_locations.push(target.start_location());
-                    },
-                    TerminatorKind::SwitchInt { ref targets, .. } => {
-                        pending_locations.extend(
-                            targets.into_iter().map(|target| target.start_location()));
-                    },
-                    TerminatorKind::Drop { target, unwind, .. } |
-                    TerminatorKind::DropAndReplace { target, unwind, .. } |
-                    TerminatorKind::Assert { target, cleanup: unwind, .. } |
-                    TerminatorKind::Yield { resume: target, drop: unwind, .. } |
-                    TerminatorKind::FalseUnwind { real_target: target, unwind, .. } => {
-                        pending_locations.push(target.start_location());
-                        if let Some(unwind) = unwind {
-                            pending_locations.push(unwind.start_location());
-                        }
-                    },
-                    TerminatorKind::Call { ref destination, cleanup, .. } => {
-                        if let Some((_, destination)) = destination {
-                            pending_locations.push(destination.start_location());
-                        }
-                        if let Some(cleanup) = cleanup {
-                            pending_locations.push(cleanup.start_location());
-                        }
-                    },
-                    TerminatorKind::FalseEdges { real_target, ref imaginary_targets, .. } => {
-                        pending_locations.push(real_target.start_location());
-                        pending_locations.extend(
-                            imaginary_targets.into_iter().map(|target| target.start_location()));
-                    },
-                    _ => {},
+
+            if location.statement_index < block.statements.len() {
+                let successor = location.successor_within_block();
+                if visited_locations.insert(successor) {
+                    pending_locations.push_back(successor);
                 }
             } else {
-                // Add the next statement to pending locations.
-                pending_locations.push(location.successor_within_block());
+                pending_locations.extend(
+                    block
+                        .terminator()
+                        .successors()
+                        .map(|bb| Location {
+                            statement_index: 0,
+                            block: *bb,
+                        })
+                        .filter(|s| visited_locations.insert(*s))
+                        .map(|s| {
+                            if self.is_back_edge(location, s) {
+                                match outmost_back_edge {
+                                    None => {
+                                        outmost_back_edge = Some(location);
+                                    }
+
+                                    Some(back_edge)
+                                        if location.dominates(back_edge, &self.dominators) =>
+                                    {
+                                        outmost_back_edge = Some(location);
+                                    }
+
+                                    Some(_) => {}
+                                }
+                            }
+
+                            s
+                        }),
+                );
             }
+        }
+
+        None
+    }
+
+    /// true if `from` location can reach `loop_head` location and `loop_head` dominates all the
+    /// intermediate nodes
+    fn can_reach_head_of_loop(&self, from: Location, loop_head: Location) -> bool {
+        self.find_loop_head_dfs(from, loop_head, &mut FxHashSet::default())
+    }
+
+    fn find_loop_head_dfs(
+        &self,
+        from: Location,
+        loop_head: Location,
+        visited_locations: &mut FxHashSet<Location>,
+    ) -> bool {
+        visited_locations.insert(from);
+
+        if from == loop_head {
+            return true;
+        }
+
+        if loop_head.dominates(from, &self.dominators) {
+            let block = &self.mir.basic_blocks()[from.block];
+
+            if from.statement_index < block.statements.len() {
+                let successor = from.successor_within_block();
+
+                if !visited_locations.contains(&successor)
+                    && self.find_loop_head_dfs(successor, loop_head, visited_locations)
+                {
+                    return true;
+                }
+            } else {
+                for bb in block.terminator().successors() {
+                    let successor = Location {
+                        statement_index: 0,
+                        block: *bb,
+                    };
 
-            // Keep track of where we have visited.
-            visited_locations.push(location);
+                    if !visited_locations.contains(&successor)
+                        && self.find_loop_head_dfs(successor, loop_head, visited_locations)
+                    {
+                        return true;
+                    }
+                }
+            }
         }
 
         false
     }
 
+    /// True if an edge `source -> target` is a backedge -- in other words, if the target
+    /// dominates the source.
+    fn is_back_edge(&self, source: Location, target: Location) -> bool {
+        target.dominates(source, &self.mir.dominators())
+    }
+
     /// Determine how the borrow was later used.
     fn later_use_kind(
         &self,
         borrow: &BorrowData<'tcx>,
         use_spans: UseSpans,
-        location: Location
+        location: Location,
     ) -> (LaterUseKind, Span) {
         match use_spans {
             UseSpans::ClosureUse { var_span, .. } => {
                 // Used in a closure.
                 (LaterUseKind::ClosureCapture, var_span)
-            },
+            }
             UseSpans::OtherUse(span) => {
                 let block = &self.mir.basic_blocks()[location.block];
 
                 let kind = if let Some(&Statement {
                     kind: StatementKind::FakeRead(FakeReadCause::ForLet, _),
                     ..
-                }) = block.statements.get(location.statement_index) {
+                }) = block.statements.get(location.statement_index)
+                {
                     LaterUseKind::FakeLetRead
                 } else if self.was_captured_by_trait_object(borrow) {
                     LaterUseKind::TraitCapture
                 } else if location.statement_index == block.statements.len() {
                     if let TerminatorKind::Call {
-                        ref func, from_hir_call: true, ..
-                    } = block.terminator().kind {
+                        ref func,
+                        from_hir_call: true,
+                        ..
+                    } = block.terminator().kind
+                    {
                         // Just point to the function, to reduce the chance of overlapping spans.
                         let function_span = match func {
                             Operand::Constant(c) => c.span,
@@ -391,7 +488,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                                 } else {
                                     span
                                 }
-                            },
+                            }
                             _ => span,
                         };
                         return (LaterUseKind::Call, function_span);
@@ -407,7 +504,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         }
     }
 
-    /// Check if a borrowed value was captured by a trait object. We do this by
+    /// Checks if a borrowed value was captured by a trait object. We do this by
     /// looking forward in the MIR from the reserve location and checking if we see
     /// a unsized cast to a trait object on our data.
     fn was_captured_by_trait_object(&self, borrow: &BorrowData<'tcx>) -> bool {
@@ -415,7 +512,10 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         let location = borrow.reserve_location;
         let block = &self.mir[location.block];
         let stmt = block.statements.get(location.statement_index);
-        debug!("was_captured_by_trait_object: location={:?} stmt={:?}", location, stmt);
+        debug!(
+            "was_captured_by_trait_object: location={:?} stmt={:?}",
+            location, stmt
+        );
 
         // We make a `queue` vector that has the locations we want to visit. As of writing, this
         // will only ever have one item at any given time, but by using a vector, we can pop from
@@ -424,13 +524,17 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
         let mut target = if let Some(&Statement {
             kind: StatementKind::Assign(Place::Local(local), _),
             ..
-        }) = stmt {
+        }) = stmt
+        {
             local
         } else {
             return false;
         };
 
-        debug!("was_captured_by_trait: target={:?} queue={:?}", target, queue);
+        debug!(
+            "was_captured_by_trait: target={:?} queue={:?}",
+            target, queue
+        );
         while let Some(current_location) = queue.pop() {
             debug!("was_captured_by_trait: target={:?}", target);
             let block = &self.mir[current_location.block];
@@ -441,55 +545,55 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 debug!("was_captured_by_trait_object: stmt={:?}", stmt);
 
                 // The only kind of statement that we care about is assignments...
-                if let StatementKind::Assign(
-                    place,
-                    box rvalue,
-                ) = &stmt.kind {
+                if let StatementKind::Assign(place, box rvalue) = &stmt.kind {
                     let into = match place {
                         Place::Local(into) => into,
                         Place::Projection(box Projection {
                             base: Place::Local(into),
                             elem: ProjectionElem::Deref,
                         }) => into,
-                        _ =>  {
+                        _ => {
                             // Continue at the next location.
                             queue.push(current_location.successor_within_block());
                             continue;
-                        },
+                        }
                     };
 
                     match rvalue {
                         // If we see a use, we should check whether it is our data, and if so
                         // update the place that we're looking for to that new place.
                         Rvalue::Use(operand) => match operand {
-                            Operand::Copy(Place::Local(from)) |
-                            Operand::Move(Place::Local(from)) if *from == target => {
+                            Operand::Copy(Place::Local(from))
+                            | Operand::Move(Place::Local(from))
+                                if *from == target =>
+                            {
                                 target = *into;
-                            },
-                            _ => {},
+                            }
+                            _ => {}
                         },
                         // If we see a unsized cast, then if it is our data we should check
                         // whether it is being cast to a trait object.
                         Rvalue::Cast(CastKind::Unsize, operand, ty) => match operand {
-                            Operand::Copy(Place::Local(from)) |
-                            Operand::Move(Place::Local(from)) if *from == target => {
+                            Operand::Copy(Place::Local(from))
+                            | Operand::Move(Place::Local(from))
+                                if *from == target =>
+                            {
                                 debug!("was_captured_by_trait_object: ty={:?}", ty);
                                 // Check the type for a trait object.
                                 return match ty.sty {
                                     // `&dyn Trait`
                                     ty::TyKind::Ref(_, ty, _) if ty.is_trait() => true,
                                     // `Box<dyn Trait>`
-                                    _ if ty.is_box() && ty.boxed_ty().is_trait() =>
-                                        true,
+                                    _ if ty.is_box() && ty.boxed_ty().is_trait() => true,
                                     // `dyn Trait`
                                     _ if ty.is_trait() => true,
                                     // Anything else.
                                     _ => false,
                                 };
-                            },
+                            }
                             _ => return false,
                         },
-                        _ => {},
+                        _ => {}
                     }
                 }
 
@@ -504,7 +608,8 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                     destination: Some((Place::Local(dest), block)),
                     args,
                     ..
-                } = &terminator.kind {
+                } = &terminator.kind
+                {
                     debug!(
                         "was_captured_by_trait_object: target={:?} dest={:?} args={:?}",
                         target, dest, args
diff --git a/src/librustc_mir/borrow_check/nll/facts.rs b/src/librustc_mir/borrow_check/nll/facts.rs
index bc33a1c9c65aa..9714398d9d63a 100644
--- a/src/librustc_mir/borrow_check/nll/facts.rs
+++ b/src/librustc_mir/borrow_check/nll/facts.rs
@@ -1,5 +1,5 @@
-use borrow_check::location::{LocationIndex, LocationTable};
-use dataflow::indexes::BorrowIndex;
+use crate::borrow_check::location::{LocationIndex, LocationTable};
+use crate::dataflow::indexes::BorrowIndex;
 use polonius_engine::AllFacts as PoloniusAllFacts;
 use polonius_engine::Atom;
 use rustc::ty::{RegionVid, TyCtxt};
@@ -13,7 +13,7 @@ use std::path::Path;
 crate type AllFacts = PoloniusAllFacts<RegionVid, BorrowIndex, LocationIndex>;
 
 crate trait AllFactsExt {
-    /// Returns true if there is a need to gather `AllFacts` given the
+    /// Returns `true` if there is a need to gather `AllFacts` given the
     /// current `-Z` flags.
     fn enabled(tcx: TyCtxt<'_, '_, '_>) -> bool;
 
diff --git a/src/librustc_mir/borrow_check/nll/invalidation.rs b/src/librustc_mir/borrow_check/nll/invalidation.rs
index 112b39952559b..3255899c86cb3 100644
--- a/src/librustc_mir/borrow_check/nll/invalidation.rs
+++ b/src/librustc_mir/borrow_check/nll/invalidation.rs
@@ -1,15 +1,15 @@
-use borrow_check::borrow_set::BorrowSet;
-use borrow_check::location::LocationTable;
-use borrow_check::{JustWrite, WriteAndRead};
-use borrow_check::{AccessDepth, Deep, Shallow};
-use borrow_check::{ReadOrWrite, Activation, Read, Reservation, Write};
-use borrow_check::{Context, ContextKind};
-use borrow_check::{LocalMutationIsAllowed, MutateMode};
-use borrow_check::ArtificialField;
-use borrow_check::{ReadKind, WriteKind};
-use borrow_check::nll::facts::AllFacts;
-use borrow_check::path_utils::*;
-use dataflow::move_paths::indexes::BorrowIndex;
+use crate::borrow_check::borrow_set::BorrowSet;
+use crate::borrow_check::location::LocationTable;
+use crate::borrow_check::{JustWrite, WriteAndRead};
+use crate::borrow_check::{AccessDepth, Deep, Shallow};
+use crate::borrow_check::{ReadOrWrite, Activation, Read, Reservation, Write};
+use crate::borrow_check::{Context, ContextKind};
+use crate::borrow_check::{LocalMutationIsAllowed, MutateMode};
+use crate::borrow_check::ArtificialField;
+use crate::borrow_check::{ReadKind, WriteKind};
+use crate::borrow_check::nll::facts::AllFacts;
+use crate::borrow_check::path_utils::*;
+use crate::dataflow::move_paths::indexes::BorrowIndex;
 use rustc::ty::TyCtxt;
 use rustc::mir::visit::Visitor;
 use rustc::mir::{BasicBlock, Location, Mir, Place, Rvalue};
@@ -53,8 +53,8 @@ struct InvalidationGenerator<'cx, 'tcx: 'cx, 'gcx: 'tcx> {
     borrow_set: &'cx BorrowSet<'tcx>,
 }
 
-/// Visits the whole MIR and generates invalidates() facts
-/// Most of the code implementing this was stolen from borrow_check/mod.rs
+/// Visits the whole MIR and generates `invalidates()` facts.
+/// Most of the code implementing this was stolen from `borrow_check/mod.rs`.
 impl<'cx, 'tcx, 'gcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx, 'gcx> {
     fn visit_statement(
         &mut self,
@@ -272,7 +272,7 @@ impl<'cx, 'tcx, 'gcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx, 'gcx> {
 }
 
 impl<'cg, 'cx, 'tcx, 'gcx> InvalidationGenerator<'cx, 'tcx, 'gcx> {
-    /// Simulates mutation of a place
+    /// Simulates mutation of a place.
     fn mutate_place(
         &mut self,
         context: Context,
@@ -288,7 +288,7 @@ impl<'cg, 'cx, 'tcx, 'gcx> InvalidationGenerator<'cx, 'tcx, 'gcx> {
         );
     }
 
-    /// Simulates consumption of an operand
+    /// Simulates consumption of an operand.
     fn consume_operand(
         &mut self,
         context: Context,
@@ -384,7 +384,7 @@ impl<'cg, 'cx, 'tcx, 'gcx> InvalidationGenerator<'cx, 'tcx, 'gcx> {
         }
     }
 
-    /// Simulates an access to a place
+    /// Simulates an access to a place.
     fn access_place(
         &mut self,
         context: Context,
@@ -472,7 +472,7 @@ impl<'cg, 'cx, 'tcx, 'gcx> InvalidationGenerator<'cx, 'tcx, 'gcx> {
     }
 
 
-    /// Generate a new invalidates(L, B) fact
+    /// Generates a new `invalidates(L, B)` fact.
     fn generate_invalidates(&mut self, b: BorrowIndex, l: Location) {
         let lidx = self.location_table.start_index(l);
         self.all_facts.invalidates.push((lidx, b));
diff --git a/src/librustc_mir/borrow_check/nll/mod.rs b/src/librustc_mir/borrow_check/nll/mod.rs
index a092c3b8ecde2..84fdbb9423e0a 100644
--- a/src/librustc_mir/borrow_check/nll/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/mod.rs
@@ -1,13 +1,14 @@
-use borrow_check::borrow_set::BorrowSet;
-use borrow_check::location::{LocationIndex, LocationTable};
-use borrow_check::nll::facts::AllFactsExt;
-use borrow_check::nll::type_check::{MirTypeckResults, MirTypeckRegionConstraints};
-use borrow_check::nll::type_check::liveness::liveness_map::NllLivenessMap;
-use borrow_check::nll::region_infer::values::RegionValueElements;
-use dataflow::indexes::BorrowIndex;
-use dataflow::move_paths::MoveData;
-use dataflow::FlowAtLocation;
-use dataflow::MaybeInitializedPlaces;
+use crate::borrow_check::borrow_set::BorrowSet;
+use crate::borrow_check::location::{LocationIndex, LocationTable};
+use crate::borrow_check::nll::facts::AllFactsExt;
+use crate::borrow_check::nll::type_check::{MirTypeckResults, MirTypeckRegionConstraints};
+use crate::borrow_check::nll::type_check::liveness::liveness_map::NllLivenessMap;
+use crate::borrow_check::nll::region_infer::values::RegionValueElements;
+use crate::dataflow::indexes::BorrowIndex;
+use crate::dataflow::move_paths::MoveData;
+use crate::dataflow::FlowAtLocation;
+use crate::dataflow::MaybeInitializedPlaces;
+use crate::transform::MirSource;
 use rustc::hir::def_id::DefId;
 use rustc::infer::InferCtxt;
 use rustc::mir::{ClosureOutlivesSubject, ClosureRegionRequirements, Mir};
@@ -19,12 +20,11 @@ use std::io;
 use std::path::PathBuf;
 use std::rc::Rc;
 use std::str::FromStr;
-use transform::MirSource;
 
 use self::mir_util::PassWhere;
 use polonius_engine::{Algorithm, Output};
-use util as mir_util;
-use util::pretty;
+use crate::util as mir_util;
+use crate::util::pretty;
 
 mod constraint_generation;
 pub mod explain_borrow;
@@ -45,7 +45,7 @@ use self::universal_regions::UniversalRegions;
 /// scraping out the set of universal regions (e.g., region parameters)
 /// declared on the function. That set will need to be given to
 /// `compute_regions`.
-pub(in borrow_check) fn replace_regions_in_mir<'cx, 'gcx, 'tcx>(
+pub(in crate::borrow_check) fn replace_regions_in_mir<'cx, 'gcx, 'tcx>(
     infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
     def_id: DefId,
     param_env: ty::ParamEnv<'tcx>,
@@ -68,7 +68,7 @@ pub(in borrow_check) fn replace_regions_in_mir<'cx, 'gcx, 'tcx>(
 /// Computes the (non-lexical) regions from the input MIR.
 ///
 /// This may result in errors being reported.
-pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
+pub(in crate::borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
     infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
     def_id: DefId,
     universal_regions: UniversalRegions<'tcx>,
@@ -209,10 +209,10 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
 
 fn dump_mir_results<'a, 'gcx, 'tcx>(
     infcx: &InferCtxt<'a, 'gcx, 'tcx>,
-    source: MirSource,
+    source: MirSource<'tcx>,
     mir: &Mir<'tcx>,
-    regioncx: &RegionInferenceContext,
-    closure_region_requirements: &Option<ClosureRegionRequirements>,
+    regioncx: &RegionInferenceContext<'_>,
+    closure_region_requirements: &Option<ClosureRegionRequirements<'_>>,
 ) {
     if !mir_util::dump_enabled(infcx.tcx, "nll", source) {
         return;
@@ -254,14 +254,14 @@ fn dump_mir_results<'a, 'gcx, 'tcx>(
     );
 
     // Also dump the inference graph constraints as a graphviz file.
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file =
             pretty::create_dump_file(infcx.tcx, "regioncx.all.dot", None, "nll", &0, source)?;
         regioncx.dump_graphviz_raw_constraints(&mut file)?;
     };
 
     // Also dump the inference graph constraints as a graphviz file.
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file =
             pretty::create_dump_file(infcx.tcx, "regioncx.scc.dot", None, "nll", &0, source)?;
         regioncx.dump_graphviz_scc_constraints(&mut file)?;
@@ -273,7 +273,7 @@ fn dump_annotation<'a, 'gcx, 'tcx>(
     mir: &Mir<'tcx>,
     mir_def_id: DefId,
     regioncx: &RegionInferenceContext<'tcx>,
-    closure_region_requirements: &Option<ClosureRegionRequirements>,
+    closure_region_requirements: &Option<ClosureRegionRequirements<'_>>,
     errors_buffer: &mut Vec<Diagnostic>,
 ) {
     let tcx = infcx.tcx;
@@ -322,7 +322,7 @@ fn dump_annotation<'a, 'gcx, 'tcx>(
 }
 
 fn for_each_region_constraint(
-    closure_region_requirements: &ClosureRegionRequirements,
+    closure_region_requirements: &ClosureRegionRequirements<'_>,
     with_msg: &mut dyn FnMut(&str) -> io::Result<()>,
 ) -> io::Result<()> {
     for req in &closure_region_requirements.outlives_requirements {
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs b/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
index df6d187e442e9..419ee73b28ad3 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/dump_mir.rs
@@ -57,7 +57,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// Debugging aid: Invokes the `with_msg` callback repeatedly with
-    /// our internal region constraints.  These are dumped into the
+    /// our internal region constraints. These are dumped into the
     /// -Zdump-mir file so that we can figure out why the region
     /// inference resulted in the values that it did when debugging.
     fn for_each_constraint(
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
index 77c8a896b04ed..081c458bfc17a 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs
@@ -1,8 +1,9 @@
-use borrow_check::nll::constraints::OutlivesConstraint;
-use borrow_check::nll::region_infer::RegionInferenceContext;
-use borrow_check::nll::type_check::Locations;
-use borrow_check::nll::universal_regions::DefiningTy;
-use borrow_check::nll::ConstraintDescription;
+use crate::borrow_check::nll::constraints::OutlivesConstraint;
+use crate::borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::nll::type_check::Locations;
+use crate::borrow_check::nll::universal_regions::DefiningTy;
+use crate::borrow_check::nll::ConstraintDescription;
+use crate::util::borrowck_errors::{BorrowckErrors, Origin};
 use rustc::hir::def_id::DefId;
 use rustc::infer::error_reporting::nice_region_error::NiceRegionError;
 use rustc::infer::InferCtxt;
@@ -15,7 +16,6 @@ use std::collections::VecDeque;
 use syntax::errors::Applicability;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
-use util::borrowck_errors::{BorrowckErrors, Origin};
 
 mod region_name;
 mod var_name;
@@ -205,7 +205,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             for constraint in self.constraint_graph
                 .outgoing_edges(r, &self.constraints, fr_static)
             {
-                assert_eq!(constraint.sup, r);
+                debug_assert_eq!(constraint.sup, r);
                 let sub_region = constraint.sub;
                 if let Trace::NotVisited = context[sub_region] {
                     context[sub_region] = Trace::FromOutlivesConstraint(constraint);
@@ -243,8 +243,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // Check if we can use one of the "nice region errors".
         if let (Some(f), Some(o)) = (self.to_error_region(fr), self.to_error_region(outlived_fr)) {
             let tables = infcx.tcx.typeck_tables_of(mir_def_id);
-            let nice = NiceRegionError::new_from_span(infcx.tcx, span, o, f, Some(tables));
-            if let Some(_error_reported) = nice.try_report_from_nll() {
+            let nice = NiceRegionError::new_from_span(infcx, span, o, f, Some(tables));
+            if let Some(diag) = nice.try_report_from_nll() {
+                diag.buffer(errors_buffer);
                 return;
             }
         }
@@ -505,7 +506,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ) {
         let mut diag = infcx.tcx.sess.struct_span_err(
             span,
-            "unsatisfied lifetime constraints", // FIXME
+            "lifetime may not live long enough"
         );
 
         let counter = &mut 1;
@@ -626,7 +627,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                             "'_".to_string()
                         };
 
-                        diag.span_suggestion_with_applicability(
+                        diag.span_suggestion(
                             span,
                             &format!(
                                 "to allow this impl Trait to capture borrowed data with lifetime \
@@ -738,8 +739,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     }
 
     /// If `r2` represents a placeholder region, then this returns
-    /// true if `r1` cannot name that placeholder in its
-    /// value. Otherwise, returns false.
+    /// `true` if `r1` cannot name that placeholder in its
+    /// value; otherwise, returns `false`.
     fn cannot_name_placeholder(&self, r1: RegionVid, r2: RegionVid) -> bool {
         debug!("cannot_name_value_of(r1={:?}, r2={:?})", r1, r2);
 
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
index bff8015511242..089640ab7024b 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
@@ -1,7 +1,7 @@
 use std::fmt::{self, Display};
-use borrow_check::nll::region_infer::RegionInferenceContext;
-use borrow_check::nll::universal_regions::DefiningTy;
-use borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::nll::universal_regions::DefiningTy;
+use crate::borrow_check::nll::ToRegionVid;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
 use rustc::infer::InferCtxt;
@@ -10,7 +10,7 @@ use rustc::ty::subst::{Substs, UnpackedKind};
 use rustc::ty::{self, RegionKind, RegionVid, Ty, TyCtxt};
 use rustc::util::ppaux::RegionHighlightMode;
 use rustc_errors::DiagnosticBuilder;
-use syntax::ast::{Name, DUMMY_NODE_ID};
+use syntax::ast::Name;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
 use syntax_pos::symbol::InternedString;
@@ -109,7 +109,7 @@ impl RegionName {
 }
 
 impl Display for RegionName {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.name)
     }
 }
@@ -173,7 +173,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         value
     }
 
-    /// Check for the case where `fr` maps to something that the
+    /// Checks for the case where `fr` maps to something that the
     /// *user* has a name for. In that case, we'll be able to map
     /// `fr` to a `Region<'tcx>`, and that region will be one of
     /// named variants.
@@ -272,7 +272,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         }
     }
 
-    /// Get a span of a named region to provide context for error messages that
+    /// Gets a span of a named region to provide context for error messages that
     /// mention that span, for example:
     ///
     /// ```
@@ -293,9 +293,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         name: &InternedString,
     ) -> Span {
         let scope = error_region.free_region_binding_scope(tcx);
-        let node = tcx.hir().as_local_node_id(scope).unwrap_or(DUMMY_NODE_ID);
+        let node = tcx.hir().as_local_hir_id(scope).unwrap_or(hir::DUMMY_HIR_ID);
 
-        let span = tcx.sess.source_map().def_span(tcx.hir().span(node));
+        let span = tcx.sess.source_map().def_span(tcx.hir().span_by_hir_id(node));
         if let Some(param) = tcx.hir()
             .get_generics(scope)
             .and_then(|generics| generics.get_named(name))
@@ -306,7 +306,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         }
     }
 
-    /// Find an argument that contains `fr` and label it with a fully
+    /// Finds an argument that contains `fr` and label it with a fully
     /// elaborated type, returning something like `'1`. Result looks
     /// like:
     ///
@@ -428,7 +428,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// to. For example, we might produce an annotation like this:
     ///
     /// ```
-    ///  | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
+    ///  | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item = &T>> {
     ///  |                - let's call the lifetime of this reference `'1`
     /// ```
     ///
@@ -437,7 +437,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// `argument_hir_ty`, a `hir::Ty` (the syntax of the type
     /// annotation). We are descending through the types stepwise,
     /// looking in to find the region `needle_fr` in the internal
-    /// type.  Once we find that, we can use the span of the `hir::Ty`
+    /// type. Once we find that, we can use the span of the `hir::Ty`
     /// to add the highlight.
     ///
     /// This is a somewhat imperfect process, so long the way we also
@@ -621,7 +621,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         None
     }
 
-    /// Find a closure upvar that contains `fr` and label it with a
+    /// Finds a closure upvar that contains `fr` and label it with a
     /// fully elaborated type, returning something like `'1`. Result
     /// looks like:
     ///
@@ -647,7 +647,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         })
     }
 
-    /// Check for arguments appearing in the (closure) return type. It
+    /// Checks for arguments appearing in the (closure) return type. It
     /// must be a closure since, in a free fn, such an argument would
     /// have to either also appear in an argument (if using elision)
     /// or be early bound (named, not in argument).
@@ -681,10 +681,13 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
         let (return_span, mir_description) = match tcx.hir().get(mir_node_id) {
             hir::Node::Expr(hir::Expr {
-                node: hir::ExprKind::Closure(_, _, _, span, gen_move),
+                node: hir::ExprKind::Closure(_, return_ty, _, span, gen_move),
                 ..
             }) => (
-                tcx.sess.source_map().end_point(*span),
+                match return_ty.output {
+                    hir::FunctionRetTy::DefaultReturn(_) => tcx.sess.source_map().end_point(*span),
+                    hir::FunctionRetTy::Return(_) => return_ty.output.span(),
+                },
                 if gen_move.is_some() {
                     " of generator"
                 } else {
@@ -711,7 +714,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         })
     }
 
-    /// Create a synthetic region named `'1`, incrementing the
+    /// Creates a synthetic region named `'1`, incrementing the
     /// counter.
     fn synthesize_region_name(&self, counter: &mut usize) -> InternedString {
         let c = *counter;
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/var_name.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/var_name.rs
index c2f2e99c0a55b..f6bbaf2db0383 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/var_name.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/var_name.rs
@@ -1,5 +1,5 @@
-use borrow_check::nll::region_infer::RegionInferenceContext;
-use borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::nll::ToRegionVid;
 use rustc::mir::{Local, Mir};
 use rustc::ty::{RegionVid, TyCtxt};
 use rustc_data_structures::indexed_vec::Idx;
@@ -71,11 +71,10 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         upvar_index: usize,
     ) -> (Symbol, Span) {
         let upvar_hir_id = mir.upvar_decls[upvar_index].var_hir_id.assert_crate_local();
-        let upvar_node_id = tcx.hir().hir_to_node_id(upvar_hir_id);
-        debug!("get_upvar_name_and_span_for_region: upvar_node_id={:?}", upvar_node_id);
+        debug!("get_upvar_name_and_span_for_region: upvar_hir_id={:?}", upvar_hir_id);
 
-        let upvar_name = tcx.hir().name(upvar_node_id);
-        let upvar_span = tcx.hir().span(upvar_node_id);
+        let upvar_name = tcx.hir().name_by_hir_id(upvar_hir_id);
+        let upvar_span = tcx.hir().span_by_hir_id(upvar_hir_id);
         debug!("get_upvar_name_and_span_for_region: upvar_name={:?} upvar_span={:?}",
                upvar_name, upvar_span);
 
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs b/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
index 2da158be432be..cffc66ac7ddfd 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/graphviz.rs
@@ -3,8 +3,7 @@
 //! data to rendered labels.
 
 use super::*;
-use borrow_check::nll::constraints::OutlivesConstraint;
-use dot;
+use crate::borrow_check::nll::constraints::OutlivesConstraint;
 use std::borrow::Cow;
 use std::io::{self, Write};
 
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
index fee5dc8646587..cbeb5dc206ee6 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs
@@ -1,9 +1,11 @@
 use super::universal_regions::UniversalRegions;
-use borrow_check::nll::constraints::graph::NormalConstraintGraph;
-use borrow_check::nll::constraints::{ConstraintSccIndex, ConstraintSet, OutlivesConstraint};
-use borrow_check::nll::region_infer::values::{PlaceholderIndices, RegionElement, ToElementIndex};
-use borrow_check::nll::type_check::free_region_relations::UniversalRegionRelations;
-use borrow_check::nll::type_check::Locations;
+use crate::borrow_check::nll::constraints::graph::NormalConstraintGraph;
+use crate::borrow_check::nll::constraints::{ConstraintSccIndex, ConstraintSet, OutlivesConstraint};
+use crate::borrow_check::nll::region_infer::values::{
+    PlaceholderIndices, RegionElement, ToElementIndex
+};
+use crate::borrow_check::nll::type_check::free_region_relations::UniversalRegionRelations;
+use crate::borrow_check::nll::type_check::Locations;
 use rustc::hir::def_id::DefId;
 use rustc::infer::canonical::QueryRegionConstraint;
 use rustc::infer::region_constraints::{GenericKind, VarInfos, VerifyBound};
@@ -13,7 +15,7 @@ use rustc::mir::{
     ConstraintCategory, Local, Location, Mir,
 };
 use rustc::ty::{self, RegionVid, Ty, TyCtxt, TypeFoldable};
-use rustc::util::common;
+use rustc::util::common::{self, ErrorReported};
 use rustc_data_structures::bit_set::BitSet;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::graph::scc::Sccs;
@@ -33,7 +35,7 @@ use self::values::{LivenessValues, RegionValueElements, RegionValues};
 use super::ToRegionVid;
 
 pub struct RegionInferenceContext<'tcx> {
-    /// Contains the definition for every region variable.  Region
+    /// Contains the definition for every region variable. Region
     /// variables are identified by their index (`RegionVid`). The
     /// definition contains information about where the region came
     /// from as well as its final inferred value.
@@ -122,7 +124,7 @@ pub(crate) enum Cause {
 }
 
 /// A "type test" corresponds to an outlives constraint between a type
-/// and a lifetime, like `T: 'x` or `<T as Foo>::Bar: 'x`.  They are
+/// and a lifetime, like `T: 'x` or `<T as Foo>::Bar: 'x`. They are
 /// translated from the `Verify` region constraints in the ordinary
 /// inference context.
 ///
@@ -135,10 +137,10 @@ pub(crate) enum Cause {
 ///
 /// In some cases, however, there are outlives relationships that are
 /// not converted into a region constraint, but rather into one of
-/// these "type tests".  The distinction is that a type test does not
+/// these "type tests". The distinction is that a type test does not
 /// influence the inference result, but instead just examines the
 /// values that we ultimately inferred for each region variable and
-/// checks that they meet certain extra criteria.  If not, an error
+/// checks that they meet certain extra criteria. If not, an error
 /// can be issued.
 ///
 /// One reason for this is that these type tests typically boil down
@@ -284,7 +286,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// Initializes the region variables for each universally
     /// quantified region (lifetime parameter). The first N variables
     /// always correspond to the regions appearing in the function
-    /// signature (both named and anonymous) and where clauses. This
+    /// signature (both named and anonymous) and where-clauses. This
     /// function iterates over those regions and initializes them with
     /// minimum values.
     ///
@@ -366,12 +368,12 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.universal_regions.to_region_vid(r)
     }
 
-    /// Add annotations for `#[rustc_regions]`; see `UniversalRegions::annotate`.
+    /// Adds annotations for `#[rustc_regions]`; see `UniversalRegions::annotate`.
     crate fn annotate(&self, tcx: TyCtxt<'_, '_, 'tcx>, err: &mut DiagnosticBuilder<'_>) {
         self.universal_regions.annotate(tcx, err)
     }
 
-    /// Returns true if the region `r` contains the point `p`.
+    /// Returns `true` if the region `r` contains the point `p`.
     ///
     /// Panics if called before `solve()` executes,
     crate fn region_contains(&self, r: impl ToRegionVid, p: impl ToElementIndex) -> bool {
@@ -391,7 +393,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.scc_universes[scc]
     }
 
-    /// Perform region inference and report errors if we see any
+    /// Performs region inference and report errors if we see any
     /// unsatisfiable constraints. If this is a closure, returns the
     /// region requirements to propagate to our creator, if any.
     pub(super) fn solve<'gcx>(
@@ -531,7 +533,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         );
     }
 
-    /// True if all the elements in the value of `scc_b` are nameable
+    /// Returns `true` if all the elements in the value of `scc_b` are nameable
     /// in `scc_a`. Used during constraint propagation, and only once
     /// the value of `scc_b` has been computed.
     fn universe_compatible(&self, scc_b: ConstraintSccIndex, scc_a: ConstraintSccIndex) -> bool {
@@ -761,20 +763,26 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
             debug!("try_promote_type_test: ur={:?}", ur);
 
-            let non_local_ub = self.universal_region_relations.non_local_upper_bound(ur);
+            let non_local_ub = self.universal_region_relations.non_local_upper_bounds(&ur);
             debug!("try_promote_type_test: non_local_ub={:?}", non_local_ub);
 
-            assert!(self.universal_regions.is_universal_region(non_local_ub));
-            assert!(!self.universal_regions.is_local_free_region(non_local_ub));
-
-            let requirement = ClosureOutlivesRequirement {
-                subject,
-                outlived_free_region: non_local_ub,
-                blame_span: locations.span(mir),
-                category: ConstraintCategory::Boring,
-            };
-            debug!("try_promote_type_test: pushing {:#?}", requirement);
-            propagated_outlives_requirements.push(requirement);
+            // This is slightly too conservative. To show T: '1, given `'2: '1`
+            // and `'3: '1` we only need to prove that T: '2 *or* T: '3, but to
+            // avoid potential non-determinism we approximate this by requiring
+            // T: '1 and T: '2.
+            for &upper_bound in non_local_ub {
+                debug_assert!(self.universal_regions.is_universal_region(upper_bound));
+                debug_assert!(!self.universal_regions.is_local_free_region(upper_bound));
+
+                let requirement = ClosureOutlivesRequirement {
+                    subject,
+                    outlived_free_region: upper_bound,
+                    blame_span: locations.span(mir),
+                    category: ConstraintCategory::Boring,
+                };
+                debug!("try_promote_type_test: pushing {:#?}", requirement);
+                propagated_outlives_requirements.push(requirement);
+            }
         }
         true
     }
@@ -926,8 +934,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         lub
     }
 
-    /// Test if `test` is true when applied to `lower_bound` at
-    /// `point`, and returns true or false.
+    /// Tests if `test` is true when applied to `lower_bound` at
+    /// `point`.
     fn eval_verify_bound(
         &self,
         tcx: TyCtxt<'_, '_, 'tcx>,
@@ -988,7 +996,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// different results. (For example, there might be two regions
     /// with the same value that are not in the same SCC).
     ///
-    /// NB. This is not an ideal approach and I would like to revisit
+    /// N.B., this is not an ideal approach and I would like to revisit
     /// it. However, it works pretty well in practice. In particular,
     /// this is needed to deal with projection outlives bounds like
     ///
@@ -996,7 +1004,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     ///
     /// In particular, this routine winds up being important when
     /// there are bounds like `where <T as Foo<'a>>::Item: 'b` in the
-    /// environment.  In this case, if we can show that `'0 == 'a`,
+    /// environment. In this case, if we can show that `'0 == 'a`,
     /// and that `'b: '1`, then we know that the clause is
     /// satisfied. In such cases, particularly due to limitations of
     /// the trait solver =), we usually wind up with a where-clause like
@@ -1075,7 +1083,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// Once regions have been propagated, this method is used to see
     /// whether any of the constraints were too strong. In particular,
     /// we want to check for a case where a universally quantified
-    /// region exceeded its bounds.  Consider:
+    /// region exceeded its bounds. Consider:
     ///
     ///     fn foo<'a, 'b>(x: &'a u32) -> &'b u32 { x }
     ///
@@ -1124,7 +1132,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         }
     }
 
-    /// Check the final value for the free region `fr` to see if it
+    /// Checks the final value for the free region `fr` to see if it
     /// grew too large. In particular, examine what `end(X)` points
     /// wound up in `fr`'s final value; for each `end(X)` where `X !=
     /// fr`, we want to check that `fr: X`. If not, that's either an
@@ -1155,63 +1163,109 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 .is_none()
         );
 
+        // Only check all of the relations for the main representative of each
+        // SCC, otherwise just check that we outlive said representative. This
+        // reduces the number of redundant relations propagated out of
+        // closures.
+        // Note that the representative will be a universal region if there is
+        // one in this SCC, so we will always check the representative here.
+        let representative = self.scc_representatives[longer_fr_scc];
+        if representative != longer_fr {
+            self.check_universal_region_relation(
+                longer_fr,
+                representative,
+                infcx,
+                mir,
+                mir_def_id,
+                propagated_outlives_requirements,
+                errors_buffer,
+            );
+            return;
+        }
+
         // Find every region `o` such that `fr: o`
         // (because `fr` includes `end(o)`).
         for shorter_fr in self.scc_values.universal_regions_outlived_by(longer_fr_scc) {
-            // If it is known that `fr: o`, carry on.
-            if self.universal_region_relations
-                .outlives(longer_fr, shorter_fr)
-            {
-                continue;
+            if let Some(ErrorReported) = self.check_universal_region_relation(
+                longer_fr,
+                shorter_fr,
+                infcx,
+                mir,
+                mir_def_id,
+                propagated_outlives_requirements,
+                errors_buffer,
+            ) {
+                // continuing to iterate just reports more errors than necessary
+                return;
             }
+        }
+    }
 
-            debug!(
-                "check_universal_region: fr={:?} does not outlive shorter_fr={:?}",
-                longer_fr, shorter_fr,
-            );
+    fn check_universal_region_relation(
+        &self,
+        longer_fr: RegionVid,
+        shorter_fr: RegionVid,
+        infcx: &InferCtxt<'_, 'gcx, 'tcx>,
+        mir: &Mir<'tcx>,
+        mir_def_id: DefId,
+        propagated_outlives_requirements: &mut Option<&mut Vec<ClosureOutlivesRequirement<'gcx>>>,
+        errors_buffer: &mut Vec<Diagnostic>,
+    ) -> Option<ErrorReported> {
+        // If it is known that `fr: o`, carry on.
+        if self.universal_region_relations
+            .outlives(longer_fr, shorter_fr)
+        {
+            return None;
+        }
 
-            let blame_span_category = self.find_outlives_blame_span(mir, longer_fr, shorter_fr);
-
-            if let Some(propagated_outlives_requirements) = propagated_outlives_requirements {
-                // Shrink `fr` until we find a non-local region (if we do).
-                // We'll call that `fr-` -- it's ever so slightly smaller than `fr`.
-                if let Some(fr_minus) = self.universal_region_relations
-                    .non_local_lower_bound(longer_fr)
-                {
-                    debug!("check_universal_region: fr_minus={:?}", fr_minus);
-
-                    // Grow `shorter_fr` until we find a non-local
-                    // region. (We always will.)  We'll call that
-                    // `shorter_fr+` -- it's ever so slightly larger than
-                    // `fr`.
-                    let shorter_fr_plus = self.universal_region_relations
-                        .non_local_upper_bound(shorter_fr);
-                    debug!(
-                        "check_universal_region: shorter_fr_plus={:?}",
-                        shorter_fr_plus
-                    );
+        debug!(
+            "check_universal_region_relation: fr={:?} does not outlive shorter_fr={:?}",
+            longer_fr, shorter_fr,
+        );
 
+        if let Some(propagated_outlives_requirements) = propagated_outlives_requirements {
+            // Shrink `longer_fr` until we find a non-local region (if we do).
+            // We'll call it `fr-` -- it's ever so slightly smaller than
+            // `longer_fr`.
+
+            if let Some(fr_minus) = self
+                .universal_region_relations
+                .non_local_lower_bound(longer_fr)
+            {
+                debug!("check_universal_region: fr_minus={:?}", fr_minus);
+
+                let blame_span_category = self.find_outlives_blame_span(mir, longer_fr, shorter_fr);
+
+                // Grow `shorter_fr` until we find some non-local regions. (We
+                // always will.)  We'll call them `shorter_fr+` -- they're ever
+                // so slightly larger than `shorter_fr`.
+                let shorter_fr_plus = self.universal_region_relations
+                    .non_local_upper_bounds(&shorter_fr);
+                debug!(
+                    "check_universal_region: shorter_fr_plus={:?}",
+                    shorter_fr_plus
+                );
+                for &&fr in &shorter_fr_plus {
                     // Push the constraint `fr-: shorter_fr+`
                     propagated_outlives_requirements.push(ClosureOutlivesRequirement {
                         subject: ClosureOutlivesSubject::Region(fr_minus),
-                        outlived_free_region: shorter_fr_plus,
+                        outlived_free_region: fr,
                         blame_span: blame_span_category.1,
                         category: blame_span_category.0,
                     });
-                    continue;
                 }
+                return None;
             }
-
-            // If we are not in a context where we can propagate
-            // errors, or we could not shrink `fr` to something
-            // smaller, then just report an error.
-            //
-            // Note: in this case, we use the unapproximated regions
-            // to report the error. This gives better error messages
-            // in some cases.
-            self.report_error(mir, infcx, mir_def_id, longer_fr, shorter_fr, errors_buffer);
-            return; // continuing to iterate just reports more errors than necessary
         }
+
+        // If we are not in a context where we can't propagate errors, or we
+        // could not shrink `fr` to something smaller, then just report an
+        // error.
+        //
+        // Note: in this case, we use the unapproximated regions to report the
+        // error. This gives better error messages in some cases.
+        self.report_error(mir, infcx, mir_def_id, longer_fr, shorter_fr, errors_buffer);
+        Some(ErrorReported)
     }
 
     fn check_bound_universal_region<'gcx>(
diff --git a/src/librustc_mir/borrow_check/nll/region_infer/values.rs b/src/librustc_mir/borrow_check/nll/region_infer/values.rs
index 88e8310db6893..ef27fdbde387f 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/values.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/values.rs
@@ -166,7 +166,7 @@ impl<N: Idx> LivenessValues<N> {
         self.points.rows()
     }
 
-    /// Adds the given element to the value for the given region. Returns true if
+    /// Adds the given element to the value for the given region. Returns whether
     /// the element is newly added (i.e., was not already present).
     crate fn add_element(&mut self, row: N, location: Location) -> bool {
         debug!("LivenessValues::add(r={:?}, location={:?})", row, location);
@@ -175,7 +175,7 @@ impl<N: Idx> LivenessValues<N> {
     }
 
     /// Adds all the elements in the given bit array into the given
-    /// region. Returns true if any of them are newly added.
+    /// region. Returns whether any of them are newly added.
     crate fn add_elements(&mut self, row: N, locations: &HybridBitSet<PointIndex>) -> bool {
         debug!(
             "LivenessValues::add_elements(row={:?}, locations={:?})",
@@ -189,7 +189,7 @@ impl<N: Idx> LivenessValues<N> {
         self.points.insert_all_into_row(row);
     }
 
-    /// True if the region `r` contains the given element.
+    /// Returns `true` if the region `r` contains the given element.
     crate fn contains(&self, row: N, location: Location) -> bool {
         let index = self.elements.point_from_location(location);
         self.points.contains(row, index)
@@ -291,7 +291,7 @@ impl<N: Idx> RegionValues<N> {
         }
     }
 
-    /// Adds the given element to the value for the given region. Returns true if
+    /// Adds the given element to the value for the given region. Returns whether
     /// the element is newly added (i.e., was not already present).
     crate fn add_element(&mut self, r: N, elem: impl ToElementIndex) -> bool {
         debug!("add(r={:?}, elem={:?})", r, elem);
@@ -303,7 +303,7 @@ impl<N: Idx> RegionValues<N> {
         self.points.insert_all_into_row(r);
     }
 
-    /// Add all elements in `r_from` to `r_to` (because e.g., `r_to:
+    /// Adds all elements in `r_from` to `r_to` (because e.g., `r_to:
     /// r_from`).
     crate fn add_region(&mut self, r_to: N, r_from: N) -> bool {
         self.points.union_rows(r_from, r_to)
@@ -311,7 +311,7 @@ impl<N: Idx> RegionValues<N> {
             | self.placeholders.union_rows(r_from, r_to)
     }
 
-    /// True if the region `r` contains the given element.
+    /// Returns `true` if the region `r` contains the given element.
     crate fn contains(&self, r: N, elem: impl ToElementIndex) -> bool {
         elem.contained_in_row(self, r)
     }
@@ -325,7 +325,7 @@ impl<N: Idx> RegionValues<N> {
         }
     }
 
-    /// True if `sup_region` contains all the CFG points that
+    /// Returns `true` if `sup_region` contains all the CFG points that
     /// `sub_region` contains. Ignores universal regions.
     crate fn contains_points(&self, sup_region: N, sub_region: N) -> bool {
         if let Some(sub_row) = self.points.row(sub_region) {
diff --git a/src/librustc_mir/borrow_check/nll/renumber.rs b/src/librustc_mir/borrow_check/nll/renumber.rs
index 5c24da7621b2d..e6a974fd8cc94 100644
--- a/src/librustc_mir/borrow_check/nll/renumber.rs
+++ b/src/librustc_mir/borrow_check/nll/renumber.rs
@@ -1,9 +1,5 @@
-use rustc::infer::canonical::Canonical;
 use rustc::ty::subst::Substs;
-use rustc::ty::{
-    self, ClosureSubsts, GeneratorSubsts, Ty, TypeFoldable, UserTypeAnnotation,
-    UserTypeAnnotationIndex,
-};
+use rustc::ty::{self, ClosureSubsts, GeneratorSubsts, Ty, TypeFoldable};
 use rustc::mir::{Location, Mir};
 use rustc::mir::visit::{MutVisitor, TyContext};
 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
@@ -59,18 +55,6 @@ impl<'a, 'gcx, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'gcx, 'tcx> {
         debug!("visit_ty: ty={:?}", ty);
     }
 
-    fn visit_user_type_annotation(
-        &mut self,
-        _index: UserTypeAnnotationIndex,
-        _ty: &mut Canonical<'tcx, UserTypeAnnotation<'tcx>>,
-    ) {
-        // User type annotations represent the types that the user
-        // wrote in the progarm. We don't want to erase the regions
-        // from these types: rather, we want to add them as
-        // constraints at type-check time.
-        debug!("visit_user_type_annotation: skipping renumber");
-    }
-
     fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, location: Location) {
         debug!("visit_substs(substs={:?}, location={:?})", substs, location);
 
diff --git a/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs b/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs
index b7555e57a62bb..1a72205ad7ae1 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/constraint_conversion.rs
@@ -1,8 +1,8 @@
-use borrow_check::nll::constraints::OutlivesConstraint;
-use borrow_check::nll::region_infer::TypeTest;
-use borrow_check::nll::type_check::{Locations, MirTypeckRegionConstraints};
-use borrow_check::nll::universal_regions::UniversalRegions;
-use borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::constraints::OutlivesConstraint;
+use crate::borrow_check::nll::region_infer::TypeTest;
+use crate::borrow_check::nll::type_check::{Locations, MirTypeckRegionConstraints};
+use crate::borrow_check::nll::universal_regions::UniversalRegions;
+use crate::borrow_check::nll::ToRegionVid;
 use rustc::infer::canonical::QueryRegionConstraint;
 use rustc::infer::outlives::env::RegionBoundPairs;
 use rustc::infer::outlives::obligations::{TypeOutlives, TypeOutlivesDelegate};
diff --git a/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs b/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
index b19dc9091cb86..3b663ef6dad61 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/free_region_relations.rs
@@ -1,7 +1,7 @@
-use borrow_check::nll::type_check::constraint_conversion;
-use borrow_check::nll::type_check::{Locations, MirTypeckRegionConstraints};
-use borrow_check::nll::universal_regions::UniversalRegions;
-use borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::type_check::constraint_conversion;
+use crate::borrow_check::nll::type_check::{Locations, MirTypeckRegionConstraints};
+use crate::borrow_check::nll::universal_regions::UniversalRegions;
+use crate::borrow_check::nll::ToRegionVid;
 use rustc::infer::canonical::QueryRegionConstraint;
 use rustc::infer::outlives::free_region_map::FreeRegionRelations;
 use rustc::infer::region_constraints::GenericKind;
@@ -19,7 +19,7 @@ crate struct UniversalRegionRelations<'tcx> {
     universal_regions: Rc<UniversalRegions<'tcx>>,
 
     /// Stores the outlives relations that are known to hold from the
-    /// implied bounds, in-scope where clauses, and that sort of
+    /// implied bounds, in-scope where-clauses, and that sort of
     /// thing.
     outlives: TransitiveRelation<RegionVid>,
 
@@ -35,7 +35,7 @@ crate struct UniversalRegionRelations<'tcx> {
 /// added via implicit bounds.
 ///
 /// Each region here is guaranteed to be a key in the `indices`
-/// map.  We use the "original" regions (i.e., the keys from the
+/// map. We use the "original" regions (i.e., the keys from the
 /// map, and not the values) because the code in
 /// `process_registered_region_obligations` has some special-cased
 /// logic expecting to see (e.g.) `ReStatic`, and if we supplied
@@ -44,7 +44,7 @@ type RegionBoundPairs<'tcx> = Vec<(ty::Region<'tcx>, GenericKind<'tcx>)>;
 
 /// As part of computing the free region relations, we also have to
 /// normalize the input-output types, which we then need later. So we
-/// return those.  This vector consists of first the input types and
+/// return those. This vector consists of first the input types and
 /// then the output type as the last element.
 type NormalizedInputsAndOutput<'tcx> = Vec<Ty<'tcx>>;
 
@@ -105,44 +105,89 @@ impl UniversalRegionRelations<'tcx> {
 
     /// Finds an "upper bound" for `fr` that is not local. In other
     /// words, returns the smallest (*) known region `fr1` that (a)
-    /// outlives `fr` and (b) is not local. This cannot fail, because
-    /// we will always find `'static` at worst.
+    /// outlives `fr` and (b) is not local.
     ///
-    /// (*) If there are multiple competing choices, we pick the "postdominating"
-    /// one. See `TransitiveRelation::postdom_upper_bound` for details.
-    crate fn non_local_upper_bound(&self, fr: RegionVid) -> RegionVid {
+    /// (*) If there are multiple competing choices, we return all of them.
+    crate fn non_local_upper_bounds(&'a self, fr: &'a RegionVid) -> Vec<&'a RegionVid> {
         debug!("non_local_upper_bound(fr={:?})", fr);
-        self.non_local_bound(&self.inverse_outlives, fr)
+        let res = self.non_local_bounds(&self.inverse_outlives, fr);
+        assert!(!res.is_empty(), "can't find an upper bound!?");
+        res
+    }
+
+    /// Returns the "postdominating" bound of the set of
+    /// `non_local_upper_bounds` for the given region.
+    crate fn non_local_upper_bound(&self, fr: RegionVid) -> RegionVid {
+        let upper_bounds = self.non_local_upper_bounds(&fr);
+
+        // In case we find more than one, reduce to one for
+        // convenience.  This is to prevent us from generating more
+        // complex constraints, but it will cause spurious errors.
+        let post_dom = self
+            .inverse_outlives
+            .mutual_immediate_postdominator(upper_bounds);
+
+        debug!("non_local_bound: post_dom={:?}", post_dom);
+
+        post_dom
+            .and_then(|&post_dom| {
+                // If the mutual immediate postdom is not local, then
+                // there is no non-local result we can return.
+                if !self.universal_regions.is_local_free_region(post_dom) {
+                    Some(post_dom)
+                } else {
+                    None
+                }
+            })
             .unwrap_or(self.universal_regions.fr_static)
     }
 
+
     /// Finds a "lower bound" for `fr` that is not local. In other
     /// words, returns the largest (*) known region `fr1` that (a) is
-    /// outlived by `fr` and (b) is not local. This cannot fail,
-    /// because we will always find `'static` at worst.
+    /// outlived by `fr` and (b) is not local.
     ///
     /// (*) If there are multiple competing choices, we pick the "postdominating"
     /// one. See `TransitiveRelation::postdom_upper_bound` for details.
     crate fn non_local_lower_bound(&self, fr: RegionVid) -> Option<RegionVid> {
         debug!("non_local_lower_bound(fr={:?})", fr);
-        self.non_local_bound(&self.outlives, fr)
+        let lower_bounds = self.non_local_bounds(&self.outlives, &fr);
+
+        // In case we find more than one, reduce to one for
+        // convenience.  This is to prevent us from generating more
+        // complex constraints, but it will cause spurious errors.
+        let post_dom = self
+            .outlives
+            .mutual_immediate_postdominator(lower_bounds);
+
+        debug!("non_local_bound: post_dom={:?}", post_dom);
+
+        post_dom
+            .and_then(|&post_dom| {
+                // If the mutual immediate postdom is not local, then
+                // there is no non-local result we can return.
+                if !self.universal_regions.is_local_free_region(post_dom) {
+                    Some(post_dom)
+                } else {
+                    None
+                }
+            })
     }
 
-    /// Helper for `non_local_upper_bound` and
-    /// `non_local_lower_bound`.  Repeatedly invokes `postdom_parent`
-    /// until we find something that is not local. Returns None if we
-    /// never do so.
-    fn non_local_bound(
+    /// Helper for `non_local_upper_bounds` and `non_local_lower_bounds`.
+    /// Repeatedly invokes `postdom_parent` until we find something that is not
+    /// local. Returns `None` if we never do so.
+    fn non_local_bounds<'a>(
         &self,
-        relation: &TransitiveRelation<RegionVid>,
-        fr0: RegionVid,
-    ) -> Option<RegionVid> {
+        relation: &'a TransitiveRelation<RegionVid>,
+        fr0: &'a RegionVid,
+    ) -> Vec<&'a RegionVid> {
         // This method assumes that `fr0` is one of the universally
         // quantified region variables.
-        assert!(self.universal_regions.is_universal_region(fr0));
+        assert!(self.universal_regions.is_universal_region(*fr0));
 
         let mut external_parents = vec![];
-        let mut queue = vec![&fr0];
+        let mut queue = vec![fr0];
 
         // Keep expanding `fr` into its parents until we reach
         // non-local regions.
@@ -157,27 +202,10 @@ impl UniversalRegionRelations<'tcx> {
 
         debug!("non_local_bound: external_parents={:?}", external_parents);
 
-        // In case we find more than one, reduce to one for
-        // convenience.  This is to prevent us from generating more
-        // complex constraints, but it will cause spurious errors.
-        let post_dom = relation
-            .mutual_immediate_postdominator(external_parents)
-            .cloned();
-
-        debug!("non_local_bound: post_dom={:?}", post_dom);
-
-        post_dom.and_then(|post_dom| {
-            // If the mutual immediate postdom is not local, then
-            // there is no non-local result we can return.
-            if !self.universal_regions.is_local_free_region(post_dom) {
-                Some(post_dom)
-            } else {
-                None
-            }
-        })
+        external_parents
     }
 
-    /// True if fr1 is known to outlive fr2.
+    /// Returns `true` if fr1 is known to outlive fr2.
     ///
     /// This will only ever be true for universally quantified regions.
     crate fn outlives(&self, fr1: RegionVid, fr2: RegionVid) -> bool {
diff --git a/src/librustc_mir/borrow_check/nll/type_check/input_output.rs b/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
index ef0f7e1b217a9..50828c294fa1b 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
@@ -7,7 +7,7 @@
 //! `RETURN_PLACE` the MIR arguments) are always fully normalized (and
 //! contain revealed `impl Trait` values).
 
-use borrow_check::nll::universal_regions::UniversalRegions;
+use crate::borrow_check::nll::universal_regions::UniversalRegions;
 use rustc::infer::LateBoundRegionConversionTime;
 use rustc::mir::*;
 use rustc::ty::Ty;
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/liveness_map.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/liveness_map.rs
index dda74e6a6a688..b9f9d83161b79 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/liveness_map.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/liveness_map.rs
@@ -6,13 +6,13 @@
 //! liveness code so that it only operates over variables with regions in their
 //! types, instead of all variables.
 
-use borrow_check::nll::ToRegionVid;
-use borrow_check::nll::facts::{AllFacts, AllFactsExt};
+use crate::borrow_check::nll::ToRegionVid;
+use crate::borrow_check::nll::facts::{AllFacts, AllFactsExt};
+use crate::util::liveness::LiveVariableMap;
 use rustc::mir::{Local, Mir};
 use rustc::ty::{RegionVid, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
-use util::liveness::LiveVariableMap;
 
 /// Map between Local and LiveVar indices: the purpose of this
 /// map is to define the subset of local variables for which we need
@@ -79,7 +79,7 @@ impl NllLivenessMap {
         }
     }
 
-    /// True if there are no local variables that need liveness computation.
+    /// Returns `true` if there are no local variables that need liveness computation.
     crate fn is_empty(&self) -> bool {
         self.to_local.is_empty()
     }
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs
index 3f13cc8b64778..e9765d2798cd7 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/local_use_map.rs
@@ -1,10 +1,10 @@
-use borrow_check::nll::region_infer::values::{PointIndex, RegionValueElements};
-use borrow_check::nll::type_check::liveness::liveness_map::{LiveVar, NllLivenessMap};
+use crate::borrow_check::nll::region_infer::values::{PointIndex, RegionValueElements};
+use crate::borrow_check::nll::type_check::liveness::liveness_map::{LiveVar, NllLivenessMap};
+use crate::util::liveness::{categorize, DefUse, LiveVariableMap};
 use rustc::mir::visit::{PlaceContext, Visitor};
 use rustc::mir::{Local, Location, Mir};
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 use rustc_data_structures::vec_linked_list as vll;
-use util::liveness::{categorize, DefUse, LiveVariableMap};
 
 /// A map that cross references each local with the locations where it
 /// is defined (assigned), used, or dropped. Used during liveness
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
index 633695a9b9ce5..28a8cad8ca200 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/mod.rs
@@ -1,11 +1,11 @@
-use borrow_check::location::LocationTable;
-use borrow_check::nll::region_infer::values::RegionValueElements;
-use borrow_check::nll::constraints::ConstraintSet;
-use borrow_check::nll::NllLivenessMap;
-use borrow_check::nll::universal_regions::UniversalRegions;
-use dataflow::move_paths::MoveData;
-use dataflow::MaybeInitializedPlaces;
-use dataflow::FlowAtLocation;
+use crate::borrow_check::location::LocationTable;
+use crate::borrow_check::nll::region_infer::values::RegionValueElements;
+use crate::borrow_check::nll::constraints::ConstraintSet;
+use crate::borrow_check::nll::NllLivenessMap;
+use crate::borrow_check::nll::universal_regions::UniversalRegions;
+use crate::dataflow::move_paths::MoveData;
+use crate::dataflow::MaybeInitializedPlaces;
+use crate::dataflow::FlowAtLocation;
 use rustc::mir::Mir;
 use rustc::ty::RegionVid;
 use rustc_data_structures::fx::FxHashSet;
@@ -23,7 +23,7 @@ mod trace;
 /// that indicate which types must be live at which point in the CFG.
 /// This vector is consumed by `constraint_generation`.
 ///
-/// NB. This computation requires normalization; therefore, it must be
+/// N.B., this computation requires normalization; therefore, it must be
 /// performed before
 pub(super) fn generate<'gcx, 'tcx>(
     typeck: &mut TypeChecker<'_, 'gcx, 'tcx>,
@@ -46,7 +46,7 @@ pub(super) fn generate<'gcx, 'tcx>(
     trace::trace(typeck, mir, elements, flow_inits, move_data, &liveness_map, location_table);
 }
 
-/// Compute all regions that are (currently) known to outlive free
+/// Computes all regions that are (currently) known to outlive free
 /// regions. For these regions, we do not need to compute
 /// liveness, since the outlives constraints will ensure that they
 /// are live over the whole fn body anyhow.
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
index 77e8dd9d130e3..4a0b4b7c205c6 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness/trace.rs
@@ -1,12 +1,13 @@
-use borrow_check::location::LocationTable;
-use borrow_check::nll::region_infer::values::{self, PointIndex, RegionValueElements};
-use borrow_check::nll::type_check::liveness::liveness_map::{LiveVar, NllLivenessMap};
-use borrow_check::nll::type_check::liveness::local_use_map::LocalUseMap;
-use borrow_check::nll::type_check::NormalizeLocation;
-use borrow_check::nll::type_check::TypeChecker;
-use dataflow::move_paths::indexes::MovePathIndex;
-use dataflow::move_paths::MoveData;
-use dataflow::{FlowAtLocation, FlowsAtLocation, MaybeInitializedPlaces};
+use crate::borrow_check::location::LocationTable;
+use crate::borrow_check::nll::region_infer::values::{self, PointIndex, RegionValueElements};
+use crate::borrow_check::nll::type_check::liveness::liveness_map::{LiveVar, NllLivenessMap};
+use crate::borrow_check::nll::type_check::liveness::local_use_map::LocalUseMap;
+use crate::borrow_check::nll::type_check::NormalizeLocation;
+use crate::borrow_check::nll::type_check::TypeChecker;
+use crate::dataflow::move_paths::indexes::MovePathIndex;
+use crate::dataflow::move_paths::MoveData;
+use crate::dataflow::{FlowAtLocation, FlowsAtLocation, MaybeInitializedPlaces};
+use crate::util::liveness::LiveVariableMap;
 use rustc::infer::canonical::QueryRegionConstraint;
 use rustc::mir::{BasicBlock, ConstraintCategory, Local, Location, Mir};
 use rustc::traits::query::dropck_outlives::DropckOutlivesResult;
@@ -16,7 +17,6 @@ use rustc::ty::{Ty, TypeFoldable};
 use rustc_data_structures::bit_set::HybridBitSet;
 use rustc_data_structures::fx::FxHashMap;
 use std::rc::Rc;
-use util::liveness::LiveVariableMap;
 
 /// This is the heart of the liveness computation. For each variable X
 /// that requires a liveness computation, it walks over all the uses
@@ -192,7 +192,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'gcx, 'tcx> {
         }
     }
 
-    /// Compute all points where local is "use live" -- meaning its
+    /// Computes all points where local is "use live" -- meaning its
     /// current value may be used later (except by a drop). This is
     /// done by walking backwards from each use of `live_local` until we
     /// find a `def` of local.
@@ -215,7 +215,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'gcx, 'tcx> {
         }
     }
 
-    /// Compute all points where local is "drop live" -- meaning its
+    /// Computes all points where local is "drop live" -- meaning its
     /// current value may be dropped later (but not used). This is
     /// done by iterating over the drops of `local` where `local` (or
     /// some subpart of `local`) is initialized. For each such drop,
@@ -407,7 +407,7 @@ impl LivenessResults<'me, 'typeck, 'flow, 'gcx, 'tcx> {
 }
 
 impl LivenessContext<'_, '_, '_, '_, 'tcx> {
-    /// True if the local variable (or some part of it) is initialized in
+    /// Returns `true` if the local variable (or some part of it) is initialized in
     /// the terminator of `block`. We need to check this to determine if a
     /// DROP of some local variable will have an effect -- note that
     /// drops, as they may unwind, are always terminators.
@@ -429,7 +429,7 @@ impl LivenessContext<'_, '_, '_, '_, 'tcx> {
         self.flow_inits.has_any_child_of(mpi).is_some()
     }
 
-    /// True if the path `mpi` (or some part of it) is initialized at
+    /// Returns `true` if the path `mpi` (or some part of it) is initialized at
     /// the exit of `block`.
     ///
     /// **Warning:** Does not account for the result of `Call`
@@ -439,7 +439,7 @@ impl LivenessContext<'_, '_, '_, '_, 'tcx> {
         self.flow_inits.has_any_child_of(mpi).is_some()
     }
 
-    /// Store the result that all regions in `value` are live for the
+    /// Stores the result that all regions in `value` are live for the
     /// points `live_at`.
     fn add_use_live_facts_for(
         &mut self,
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index 180aa1907e8d1..49f90eb90aaf0 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -2,24 +2,25 @@
 
 #![allow(unreachable_code)]
 
-use borrow_check::borrow_set::BorrowSet;
-use borrow_check::location::LocationTable;
-use borrow_check::nll::constraints::{ConstraintSet, OutlivesConstraint};
-use borrow_check::nll::facts::AllFacts;
-use borrow_check::nll::region_infer::values::LivenessValues;
-use borrow_check::nll::region_infer::values::PlaceholderIndex;
-use borrow_check::nll::region_infer::values::PlaceholderIndices;
-use borrow_check::nll::region_infer::values::RegionValueElements;
-use borrow_check::nll::region_infer::{ClosureRegionRequirementsExt, TypeTest};
-use borrow_check::nll::renumber;
-use borrow_check::nll::type_check::free_region_relations::{
+use crate::borrow_check::borrow_set::BorrowSet;
+use crate::borrow_check::location::LocationTable;
+use crate::borrow_check::nll::constraints::{ConstraintSet, OutlivesConstraint};
+use crate::borrow_check::nll::facts::AllFacts;
+use crate::borrow_check::nll::region_infer::values::LivenessValues;
+use crate::borrow_check::nll::region_infer::values::PlaceholderIndex;
+use crate::borrow_check::nll::region_infer::values::PlaceholderIndices;
+use crate::borrow_check::nll::region_infer::values::RegionValueElements;
+use crate::borrow_check::nll::region_infer::{ClosureRegionRequirementsExt, TypeTest};
+use crate::borrow_check::nll::renumber;
+use crate::borrow_check::nll::type_check::free_region_relations::{
     CreateResult, UniversalRegionRelations,
 };
-use borrow_check::nll::universal_regions::{DefiningTy, UniversalRegions};
-use borrow_check::nll::ToRegionVid;
-use dataflow::move_paths::MoveData;
-use dataflow::FlowAtLocation;
-use dataflow::MaybeInitializedPlaces;
+use crate::borrow_check::nll::universal_regions::{DefiningTy, UniversalRegions};
+use crate::borrow_check::nll::ToRegionVid;
+use crate::dataflow::move_paths::MoveData;
+use crate::dataflow::FlowAtLocation;
+use crate::dataflow::MaybeInitializedPlaces;
+use crate::transform::{MirPass, MirSource};
 use either::Either;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
@@ -35,10 +36,10 @@ use rustc::traits::query::type_op::custom::CustomTypeOp;
 use rustc::traits::query::{Fallible, NoSolution};
 use rustc::traits::{ObligationCause, PredicateObligations};
 use rustc::ty::fold::TypeFoldable;
-use rustc::ty::subst::{Subst, Substs, UnpackedKind};
+use rustc::ty::subst::{Subst, Substs, UnpackedKind, UserSubsts};
 use rustc::ty::{
-    self, RegionVid, ToPolyTraitRef, Ty, TyCtxt, TyKind, UserTypeAnnotation,
-    UserTypeAnnotationIndex,
+    self, RegionVid, ToPolyTraitRef, Ty, TyCtxt, TyKind, UserType,
+    CanonicalUserTypeAnnotation, UserTypeAnnotationIndex,
 };
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
@@ -46,7 +47,6 @@ use rustc::ty::layout::VariantIdx;
 use std::rc::Rc;
 use std::{fmt, iter};
 use syntax_pos::{Span, DUMMY_SP};
-use transform::{MirPass, MirSource};
 
 macro_rules! span_mirbug {
     ($context:expr, $elem:expr, $($message:tt)*) => ({
@@ -210,7 +210,7 @@ fn type_check_internal<'a, 'gcx, 'tcx, R>(
     extra(&mut checker)
 }
 
-fn translate_outlives_facts(cx: &mut BorrowCheckContext) {
+fn translate_outlives_facts(cx: &mut BorrowCheckContext<'_, '_>) {
     if let Some(facts) = cx.all_facts {
         let location_table = cx.location_table;
         facts
@@ -235,7 +235,7 @@ fn translate_outlives_facts(cx: &mut BorrowCheckContext) {
     }
 }
 
-fn mirbug(tcx: TyCtxt, span: Span, msg: &str) {
+fn mirbug(tcx: TyCtxt<'_, '_, '_>, span: Span, msg: &str) {
     // We sometimes see MIR failures (notably predicate failures) due to
     // the fact that we check rvalue sized predicates here. So use `delay_span_bug`
     // to avoid reporting bugs in those cases.
@@ -266,7 +266,7 @@ impl<'a, 'b, 'gcx, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'gcx, 'tcx> {
         }
     }
 
-    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
+    fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext<'_>, location: Location) {
         self.sanitize_place(place, location, context);
     }
 
@@ -283,7 +283,7 @@ impl<'a, 'b, 'gcx, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'gcx, 'tcx> {
                 location.to_locations(),
                 ConstraintCategory::Boring,
             ) {
-                let annotation = self.cx.instantiated_type_annotations[&annotation_index];
+                let annotation = &self.mir.user_type_annotations[annotation_index];
                 span_mirbug!(
                     self,
                     constant,
@@ -293,6 +293,39 @@ impl<'a, 'b, 'gcx, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'gcx, 'tcx> {
                     terr,
                 );
             }
+        } else {
+            match *constant.literal {
+                ty::LazyConst::Unevaluated(def_id, substs) => {
+                    if let Err(terr) = self.cx.fully_perform_op(
+                        location.to_locations(),
+                        ConstraintCategory::Boring,
+                        self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
+                            constant.ty, def_id, UserSubsts { substs, user_self_ty: None },
+                        )),
+                    ) {
+                        span_mirbug!(
+                            self,
+                            constant,
+                            "bad constant type {:?} ({:?})",
+                            constant,
+                            terr
+                        );
+                    }
+                }
+                ty::LazyConst::Evaluated(lit) => {
+                    if let ty::FnDef(def_id, substs) = lit.ty.sty {
+                        let tcx = self.tcx();
+
+                        let instantiated_predicates = tcx
+                            .predicates_of(def_id)
+                            .instantiate(tcx, substs);
+                        self.cx.normalize_and_prove_instantiated_predicates(
+                            instantiated_predicates,
+                            location.to_locations(),
+                        );
+                    }
+                }
+            }
         }
     }
 
@@ -374,8 +407,9 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
         }
     }
 
-    /// Checks that the constant's `ty` field matches up with what
-    /// would be expected from its literal.
+    /// Checks that the constant's `ty` field matches up with what would be
+    /// expected from its literal. Unevaluated constants and well-formed
+    /// constraints are checked by `visit_constant`.
     fn sanitize_constant(&mut self, constant: &Constant<'tcx>, location: Location) {
         debug!(
             "sanitize_constant(constant={:?}, location={:?})",
@@ -387,35 +421,6 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
             ty::LazyConst::Unevaluated(..) => return,
         };
 
-        // FIXME(#46702) -- We need some way to get the predicates
-        // associated with the "pre-evaluated" form of the
-        // constant. For example, consider that the constant
-        // may have associated constant projections (`<Foo as
-        // Trait<'a, 'b>>::SOME_CONST`) that impose
-        // constraints on `'a` and `'b`. These constraints
-        // would be lost if we just look at the normalized
-        // value.
-        if let ty::FnDef(def_id, substs) = literal.ty.sty {
-            let tcx = self.tcx();
-            let type_checker = &mut self.cx;
-
-            // FIXME -- For now, use the substitutions from
-            // `value.ty` rather than `value.val`. The
-            // renumberer will rewrite them to independent
-            // sets of regions; in principle, we ought to
-            // derive the type of the `value.val` from "first
-            // principles" and equate with value.ty, but as we
-            // are transitioning to the miri-based system, we
-            // don't have a handy function for that, so for
-            // now we just ignore `value.val` regions.
-
-            let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
-            type_checker.normalize_and_prove_instantiated_predicates(
-                instantiated_predicates,
-                location.to_locations(),
-            );
-        }
-
         debug!("sanitize_constant: expected_ty={:?}", literal.ty);
 
         if let Err(terr) = self.cx.eq_types(
@@ -442,7 +447,7 @@ impl<'a, 'b, 'gcx, 'tcx> TypeVerifier<'a, 'b, 'gcx, 'tcx> {
         &mut self,
         place: &Place<'tcx>,
         location: Location,
-        context: PlaceContext,
+        context: PlaceContext<'_>,
     ) -> PlaceTy<'tcx> {
         debug!("sanitize_place: {:?}", place);
         let place_ty = match *place {
@@ -740,15 +745,6 @@ struct TypeChecker<'a, 'gcx: 'tcx, 'tcx: 'a> {
     reported_errors: FxHashSet<(Ty<'tcx>, Span)>,
     borrowck_context: Option<&'a mut BorrowCheckContext<'a, 'tcx>>,
     universal_region_relations: Option<&'a UniversalRegionRelations<'tcx>>,
-    /// For each user-type annotation (identified by a UserTypeAnnotationIndex), we create
-    /// an "instantiated" version at the beginning of type check, which replaces each
-    /// canonical variable with a fresh inference variable. These instantiated versions are
-    /// stored either in this field or in user_substs, depending on the kind of user-type
-    /// annotation. They are then referenced by the code which has the job of enforcing these
-    /// annotations. Part of the reason for this setup is that it allows us to enforce basic
-    /// WF criteria on the types even if the code that referenced them is dead
-    /// code (see #54943).
-    instantiated_type_annotations: FxHashMap<UserTypeAnnotationIndex, UserTypeAnnotation<'tcx>>,
 }
 
 struct BorrowCheckContext<'a, 'tcx: 'a> {
@@ -843,7 +839,7 @@ pub enum Locations {
     /// older NLL analysis, we required this only at the entry point
     /// to the function. By the nature of the constraints, this wound
     /// up propagating to all points reachable from start (because
-    /// `'1` -- as a universal region -- is live everywhere).  In the
+    /// `'1` -- as a universal region -- is live everywhere). In the
     /// newer analysis, though, this doesn't work: `_0` is considered
     /// dead at the start (it has no usable value) and hence this type
     /// equality is basically a no-op. Then, later on, when we do `_0
@@ -905,36 +901,69 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             borrowck_context,
             reported_errors: Default::default(),
             universal_region_relations,
-            instantiated_type_annotations: Default::default(),
         };
-        checker.instantiate_user_type_annotations();
+        checker.check_user_type_annotations();
         checker
     }
 
-    /// Instantiate canonical types from user type annotations in the `Mir` into the
-    /// `TypeChecker`. Used when relating user type annotations and when checking if
-    /// annotations are well-formed.
-    fn instantiate_user_type_annotations(&mut self) {
+    /// Equate the inferred type and the annotated type for user type annotations
+    fn check_user_type_annotations(&mut self) {
         debug!(
-            "instantiate_user_type_annotations: user_type_annotations={:?}",
+            "check_user_type_annotations: user_type_annotations={:?}",
              self.mir.user_type_annotations
         );
-        for annotation_index in self.mir.user_type_annotations.indices() {
-            let (span, canonical_annotation) = &self.mir.user_type_annotations[annotation_index];
-            let (mut annotation, _) = self.infcx.instantiate_canonical_with_fresh_inference_vars(
-                *span, &canonical_annotation
+        for user_annotation in &self.mir.user_type_annotations {
+            let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
+            let (annotation, _) = self.infcx.instantiate_canonical_with_fresh_inference_vars(
+                span, user_ty
             );
             match annotation {
-                UserTypeAnnotation::Ty(ref mut ty) =>
-                    *ty = self.normalize(ty, Locations::All(*span)),
-                _ => {},
+                UserType::Ty(mut ty) => {
+                    ty = self.normalize(ty, Locations::All(span));
+
+                    if let Err(terr) = self.eq_types(
+                        ty,
+                        inferred_ty,
+                        Locations::All(span),
+                        ConstraintCategory::BoringNoLocation,
+                    ) {
+                        span_mirbug!(
+                            self,
+                            user_annotation,
+                            "bad user type ({:?} = {:?}): {:?}",
+                            ty,
+                            inferred_ty,
+                            terr
+                        );
+                    }
+
+                    self.prove_predicate(
+                        ty::Predicate::WellFormed(inferred_ty),
+                        Locations::All(span),
+                        ConstraintCategory::TypeAnnotation,
+                    );
+                },
+                UserType::TypeOf(def_id, user_substs) => {
+                    if let Err(terr) = self.fully_perform_op(
+                        Locations::All(span),
+                        ConstraintCategory::BoringNoLocation,
+                        self.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
+                            inferred_ty, def_id, user_substs,
+                        )),
+                    ) {
+                        span_mirbug!(
+                            self,
+                            user_annotation,
+                            "bad user type AscribeUserType({:?}, {:?} {:?}): {:?}",
+                            inferred_ty,
+                            def_id,
+                            user_substs,
+                            terr
+                        );
+                    }
+                },
             }
-            self.instantiated_type_annotations.insert(annotation_index, annotation);
         }
-        debug!(
-            "instantiate_user_type_annotations: instantiated_type_annotations={:?}",
-            self.instantiated_type_annotations,
-        );
     }
 
     /// Given some operation `op` that manipulates types, proves
@@ -1066,58 +1095,23 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             a, v, user_ty, locations,
         );
 
-        let type_annotation = self.instantiated_type_annotations[&user_ty.base];
-        match type_annotation {
-            UserTypeAnnotation::Ty(ty) => {
-                // The `TypeRelating` code assumes that "unresolved inference
-                // variables" appear in the "a" side, so flip `Contravariant`
-                // ambient variance to get the right relationship.
-                let v1 = ty::Contravariant.xform(v);
-                let tcx = self.infcx.tcx;
+        let annotated_type = self.mir.user_type_annotations[user_ty.base].inferred_ty;
+        let mut curr_projected_ty = PlaceTy::from_ty(annotated_type);
 
-                // We need to follow any provided projetions into the type.
-                //
-                // if we hit a ty var as we descend, then just skip the
-                // attempt to relate the mir local with any type.
-                #[derive(Debug)] struct HitTyVar;
-                let mut curr_projected_ty: Result<PlaceTy, HitTyVar>;
-
-                curr_projected_ty = Ok(PlaceTy::from_ty(ty));
-                for proj in &user_ty.projs {
-                    let projected_ty = if let Ok(projected_ty) = curr_projected_ty {
-                        projected_ty
-                    } else {
-                        break;
-                    };
-                    curr_projected_ty = projected_ty.projection_ty_core(
-                        tcx, proj, |this, field, &()| {
-                            if this.to_ty(tcx).is_ty_var() {
-                                Err(HitTyVar)
-                            } else {
-                                let ty = this.field_ty(tcx, field);
-                                Ok(self.normalize(ty, locations))
-                            }
-                        });
-                }
-                debug!("user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
-                       user_ty.base, ty, user_ty.projs, curr_projected_ty);
+        let tcx = self.infcx.tcx;
 
-                if let Ok(projected_ty) = curr_projected_ty {
-                    let ty = projected_ty.to_ty(tcx);
-                    self.relate_types(ty, v1, a, locations, category)?;
-                }
-            }
-            UserTypeAnnotation::TypeOf(def_id, user_substs) => {
-                let projs = self.infcx.tcx.intern_projs(&user_ty.projs);
-                self.fully_perform_op(
-                    locations,
-                    category,
-                    self.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
-                        a, v, def_id, user_substs, projs,
-                    )),
-                )?;
-            }
+        for proj in &user_ty.projs {
+            let projected_ty = curr_projected_ty.projection_ty_core(tcx, proj, |this, field, &()| {
+                let ty = this.field_ty(tcx, field);
+                self.normalize(ty, locations)
+            });
+            curr_projected_ty = projected_ty;
         }
+        debug!("user_ty base: {:?} freshened: {:?} projs: {:?} yields: {:?}",
+                user_ty.base, annotated_type, user_ty.projs, curr_projected_ty);
+
+        let ty = curr_projected_ty.to_ty(tcx);
+        self.relate_types(a, v, ty, locations, category)?;
 
         Ok(())
     }
@@ -1286,7 +1280,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                         location.to_locations(),
                         ConstraintCategory::Boring,
                     ) {
-                        let annotation = self.instantiated_type_annotations[&annotation_index];
+                        let annotation = &mir.user_type_annotations[annotation_index];
                         span_mirbug!(
                             self,
                             stmt,
@@ -1345,7 +1339,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                     Locations::All(stmt.source_info.span),
                     ConstraintCategory::TypeAnnotation,
                 ) {
-                    let annotation = self.instantiated_type_annotations[&projection.base];
+                    let annotation = &mir.user_type_annotations[projection.base];
                     span_mirbug!(
                         self,
                         stmt,
@@ -2085,7 +2079,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Add the constraints that arise from a borrow expression `&'a P` at the location `L`.
+    /// Adds the constraints that arise from a borrow expression `&'a P` at the location `L`.
     ///
     /// # Parameters
     ///
@@ -2433,8 +2427,13 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
 pub struct TypeckMir;
 
 impl MirPass for TypeckMir {
-    fn run_pass<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, src: MirSource, mir: &mut Mir<'tcx>) {
-        let def_id = src.def_id;
+    fn run_pass<'a, 'tcx>(
+        &self,
+        tcx: TyCtxt<'a, 'tcx, 'tcx>,
+        src: MirSource<'tcx>,
+        mir: &mut Mir<'tcx>,
+    ) {
+        let def_id = src.def_id();
         debug!("run_pass: {:?}", def_id);
 
         // When NLL is enabled, the borrow checker runs the typeck
diff --git a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
index 74ad7d988cc1a..28835b959d76f 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
@@ -1,5 +1,5 @@
-use borrow_check::nll::constraints::OutlivesConstraint;
-use borrow_check::nll::type_check::{BorrowCheckContext, Locations};
+use crate::borrow_check::nll::constraints::OutlivesConstraint;
+use crate::borrow_check::nll::type_check::{BorrowCheckContext, Locations};
 use rustc::infer::nll_relate::{TypeRelating, TypeRelatingDelegate, NormalizationStrategy};
 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
 use rustc::mir::ConstraintCategory;
@@ -14,7 +14,7 @@ use rustc::ty::{self, Ty};
 /// - "Invariant" `a == b`
 /// - "Contravariant" `a :> b`
 ///
-/// NB. The type `a` is permitted to have unresolved inference
+/// N.B., the type `a` is permitted to have unresolved inference
 /// variables, but not the type `b`.
 pub(super) fn relate_types<'tcx>(
     infcx: &InferCtxt<'_, '_, 'tcx>,
diff --git a/src/librustc_mir/borrow_check/nll/universal_regions.rs b/src/librustc_mir/borrow_check/nll/universal_regions.rs
index c63d45ce1d272..a5bf158257700 100644
--- a/src/librustc_mir/borrow_check/nll/universal_regions.rs
+++ b/src/librustc_mir/borrow_check/nll/universal_regions.rs
@@ -35,15 +35,15 @@ pub struct UniversalRegions<'tcx> {
     pub fr_static: RegionVid,
 
     /// A special region vid created to represent the current MIR fn
-    /// body.  It will outlive the entire CFG but it will not outlive
+    /// body. It will outlive the entire CFG but it will not outlive
     /// any other universal regions.
     pub fr_fn_body: RegionVid,
 
     /// We create region variables such that they are ordered by their
     /// `RegionClassification`. The first block are globals, then
-    /// externals, then locals. So things from:
-    /// - `FIRST_GLOBAL_INDEX..first_extern_index` are global;
-    /// - `first_extern_index..first_local_index` are external; and
+    /// externals, then locals. So, things from:
+    /// - `FIRST_GLOBAL_INDEX..first_extern_index` are global,
+    /// - `first_extern_index..first_local_index` are external,
     /// - `first_local_index..num_universals` are local.
     first_extern_index: usize,
 
@@ -54,21 +54,21 @@ pub struct UniversalRegions<'tcx> {
     num_universals: usize,
 
     /// The "defining" type for this function, with all universal
-    /// regions instantiated.  For a closure or generator, this is the
+    /// regions instantiated. For a closure or generator, this is the
     /// closure type, but for a top-level function it's the `FnDef`.
     pub defining_ty: DefiningTy<'tcx>,
 
     /// The return type of this function, with all regions replaced by
     /// their universal `RegionVid` equivalents.
     ///
-    /// NB. Associated types in this type have not been normalized,
+    /// N.B., associated types in this type have not been normalized,
     /// as the name suggests. =)
     pub unnormalized_output_ty: Ty<'tcx>,
 
     /// The fully liberated input types of this function, with all
     /// regions replaced by their universal `RegionVid` equivalents.
     ///
-    /// NB. Associated types in these types have not been normalized,
+    /// N.B., associated types in these types have not been normalized,
     /// as the name suggests. =)
     pub unnormalized_input_tys: &'tcx [Ty<'tcx>],
 
@@ -92,7 +92,7 @@ pub enum DefiningTy<'tcx> {
     /// `ClosureSubsts::generator_return_ty`.
     Generator(DefId, ty::GeneratorSubsts<'tcx>, hir::GeneratorMovability),
 
-    /// The MIR is a fn item with the given def-id and substs. The signature
+    /// The MIR is a fn item with the given `DefId` and substs. The signature
     /// of the function can be bound then with the `fn_sig` query.
     FnDef(DefId, &'tcx Substs<'tcx>),
 
@@ -174,13 +174,13 @@ pub enum RegionClassification {
 
     /// A **local** lifetime is one about which we know the full set
     /// of relevant constraints (that is, relationships to other named
-    /// regions).  For a closure, this includes any region bound in
-    /// the closure's signature.  For a fn item, this includes all
+    /// regions). For a closure, this includes any region bound in
+    /// the closure's signature. For a fn item, this includes all
     /// regions other than global ones.
     ///
     /// Continuing with the example from `External`, if we were
     /// analyzing the closure, then `'x` would be local (and `'a` and
-    /// `'b` are external).  If we are analyzing the function item
+    /// `'b` are external). If we are analyzing the function item
     /// `foo`, then `'a` and `'b` are local (and `'x` is not in
     /// scope).
     Local,
@@ -245,7 +245,7 @@ impl<'tcx> UniversalRegions<'tcx> {
         region_mapping
     }
 
-    /// True if `r` is a member of this set of universal regions.
+    /// Returns `true` if `r` is a member of this set of universal regions.
     pub fn is_universal_region(&self, r: RegionVid) -> bool {
         (FIRST_GLOBAL_INDEX..self.num_universals).contains(&r.index())
     }
@@ -271,7 +271,7 @@ impl<'tcx> UniversalRegions<'tcx> {
         (FIRST_GLOBAL_INDEX..self.num_universals).map(RegionVid::new)
     }
 
-    /// True if `r` is classified as an local region.
+    /// Returns `true` if `r` is classified as an local region.
     pub fn is_local_free_region(&self, r: RegionVid) -> bool {
         self.region_classification(r) == Some(RegionClassification::Local)
     }
@@ -290,7 +290,7 @@ impl<'tcx> UniversalRegions<'tcx> {
         self.first_local_index
     }
 
-    /// Get an iterator over all the early-bound regions that have names.
+    /// Gets an iterator over all the early-bound regions that have names.
     pub fn named_universal_regions<'s>(
         &'s self,
     ) -> impl Iterator<Item = (ty::Region<'tcx>, ty::RegionVid)> + 's {
@@ -476,12 +476,13 @@ impl<'cx, 'gcx, 'tcx> UniversalRegionsBuilder<'cx, 'gcx, 'tcx> {
         let closure_base_def_id = tcx.closure_base_def_id(self.mir_def_id);
 
         match tcx.hir().body_owner_kind(self.mir_node_id) {
+            BodyOwnerKind::Closure |
             BodyOwnerKind::Fn => {
                 let defining_ty = if self.mir_def_id == closure_base_def_id {
                     tcx.type_of(closure_base_def_id)
                 } else {
                     let tables = tcx.typeck_tables_of(self.mir_def_id);
-                    tables.node_id_to_type(self.mir_hir_id)
+                    tables.node_type(self.mir_hir_id)
                 };
 
                 debug!("defining_ty (pre-replacement): {:?}", defining_ty);
@@ -691,7 +692,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'cx, 'gcx, 'tcx> {
     /// indices vector. Typically, we identify late-bound regions as we process the inputs and
     /// outputs of the closure/function. However, sometimes there are late-bound regions which do
     /// not appear in the fn parameters but which are nonetheless in scope. The simplest case of
-    /// this are unused functions, like fn foo<'a>() { } (see eg., #51351). Despite not being used,
+    /// this are unused functions, like fn foo<'a>() { } (see e.g., #51351). Despite not being used,
     /// users can still reference these regions (e.g., let x: &'a u32 = &22;), so we need to create
     /// entries for them and store them in the indices map. This code iterates over the complete
     /// set of late-bound regions and checks for any that we have not yet seen, adding them to the
@@ -745,7 +746,7 @@ impl<'tcx> UniversalRegionIndices<'tcx> {
         }
     }
 
-    /// Replace all free regions in `value` with region vids, as
+    /// Replaces all free regions in `value` with region vids, as
     /// returned by `to_region_vid`.
     pub fn fold_to_region_vids<T>(&self, tcx: TyCtxt<'_, '_, 'tcx>, value: &T) -> T
     where
@@ -770,9 +771,8 @@ fn for_each_late_bound_region_defined_on<'tcx>(
                 owner: fn_def_id.index,
                 local_id: *late_bound,
             };
-            let region_node_id = tcx.hir().hir_to_node_id(hir_id);
-            let name = tcx.hir().name(region_node_id).as_interned_str();
-            let region_def_id = tcx.hir().local_def_id(region_node_id);
+            let name = tcx.hir().name_by_hir_id(hir_id).as_interned_str();
+            let region_def_id = tcx.hir().local_def_id_from_hir_id(hir_id);
             let liberated_region = tcx.mk_region(ty::ReFree(ty::FreeRegion {
                 scope: fn_def_id,
                 bound_region: ty::BoundRegion::BrNamed(region_def_id, name),
diff --git a/src/librustc_mir/borrow_check/path_utils.rs b/src/librustc_mir/borrow_check/path_utils.rs
index 6875aced8d231..9073ae6bed5b2 100644
--- a/src/librustc_mir/borrow_check/path_utils.rs
+++ b/src/librustc_mir/borrow_check/path_utils.rs
@@ -1,14 +1,14 @@
-use borrow_check::borrow_set::{BorrowSet, BorrowData, TwoPhaseActivation};
-use borrow_check::places_conflict;
-use borrow_check::Context;
-use borrow_check::AccessDepth;
-use dataflow::indexes::BorrowIndex;
+use crate::borrow_check::borrow_set::{BorrowSet, BorrowData, TwoPhaseActivation};
+use crate::borrow_check::places_conflict;
+use crate::borrow_check::Context;
+use crate::borrow_check::AccessDepth;
+use crate::dataflow::indexes::BorrowIndex;
 use rustc::mir::{BasicBlock, Location, Mir, Place};
 use rustc::mir::{ProjectionElem, BorrowKind};
 use rustc::ty::TyCtxt;
 use rustc_data_structures::graph::dominators::Dominators;
 
-/// Returns true if the borrow represented by `kind` is
+/// Returns `true` if the borrow represented by `kind` is
 /// allowed to be split into separate Reservation and
 /// Activation phases.
 pub(super) fn allow_two_phase_borrow<'a, 'tcx, 'gcx: 'tcx>(
diff --git a/src/librustc_mir/borrow_check/place_ext.rs b/src/librustc_mir/borrow_check/place_ext.rs
index 4d0b25b1024a3..d6d2861b557ab 100644
--- a/src/librustc_mir/borrow_check/place_ext.rs
+++ b/src/librustc_mir/borrow_check/place_ext.rs
@@ -2,11 +2,11 @@ use rustc::hir;
 use rustc::mir::ProjectionElem;
 use rustc::mir::{Local, Mir, Place, Mutability};
 use rustc::ty::{self, TyCtxt};
-use borrow_check::borrow_set::LocalsStateAtExit;
+use crate::borrow_check::borrow_set::LocalsStateAtExit;
 
 /// Extension methods for the `Place` type.
 crate trait PlaceExt<'tcx> {
-    /// Returns true if we can safely ignore borrows of this place.
+    /// Returns `true` if we can safely ignore borrows of this place.
     /// This is true whenever there is no action that the user can do
     /// to the place `self` that would invalidate the borrow. This is true
     /// for borrows of raw pointer dereferents as well as shared references.
diff --git a/src/librustc_mir/borrow_check/places_conflict.rs b/src/librustc_mir/borrow_check/places_conflict.rs
index ac7182abb36da..b5175cf41dd5c 100644
--- a/src/librustc_mir/borrow_check/places_conflict.rs
+++ b/src/librustc_mir/borrow_check/places_conflict.rs
@@ -1,6 +1,6 @@
-use borrow_check::ArtificialField;
-use borrow_check::Overlap;
-use borrow_check::{Deep, Shallow, AccessDepth};
+use crate::borrow_check::ArtificialField;
+use crate::borrow_check::Overlap;
+use crate::borrow_check::{Deep, Shallow, AccessDepth};
 use rustc::hir;
 use rustc::mir::{BorrowKind, Mir, Place};
 use rustc::mir::{Projection, ProjectionElem};
@@ -275,10 +275,10 @@ fn place_components_conflict<'gcx, 'tcx>(
 
 /// A linked list of places running up the stack; begins with the
 /// innermost place and extends to projections (e.g., `a.b` would have
-/// the place `a` with a "next" pointer to `a.b`).  Created by
+/// the place `a` with a "next" pointer to `a.b`). Created by
 /// `unroll_place`.
 ///
-/// N.B., this particular impl strategy is not the most obvious.  It was
+/// N.B., this particular impl strategy is not the most obvious. It was
 /// chosen because it makes a measurable difference to NLL
 /// performance, as this code (`borrow_conflicts_with_place`) is somewhat hot.
 struct PlaceComponents<'p, 'tcx: 'p> {
diff --git a/src/librustc_mir/borrow_check/used_muts.rs b/src/librustc_mir/borrow_check/used_muts.rs
index 0ff7ff4de10de..8c7359bdee768 100644
--- a/src/librustc_mir/borrow_check/used_muts.rs
+++ b/src/librustc_mir/borrow_check/used_muts.rs
@@ -3,7 +3,7 @@ use rustc::mir::{BasicBlock, Local, Location, Place, Statement, StatementKind, T
 
 use rustc_data_structures::fx::FxHashSet;
 
-use borrow_check::MirBorrowckCtxt;
+use crate::borrow_check::MirBorrowckCtxt;
 
 impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
     /// Walks the MIR adding to the set of `used_mut` locals that will be ignored for the purposes
diff --git a/src/librustc_mir/build/block.rs b/src/librustc_mir/build/block.rs
index f3d89a7a02515..7d93e131a6ca9 100644
--- a/src/librustc_mir/build/block.rs
+++ b/src/librustc_mir/build/block.rs
@@ -1,7 +1,7 @@
-use build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use build::ForGuard::OutsideGuard;
-use build::matches::ArmHasGuard;
-use hair::*;
+use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
+use crate::build::ForGuard::OutsideGuard;
+use crate::build::matches::ArmHasGuard;
+use crate::hair::*;
 use rustc::mir::*;
 use rustc::hir;
 use syntax_pos::Span;
diff --git a/src/librustc_mir/build/cfg.rs b/src/librustc_mir/build/cfg.rs
index a9e468db1d1b7..778d1e71cedfc 100644
--- a/src/librustc_mir/build/cfg.rs
+++ b/src/librustc_mir/build/cfg.rs
@@ -1,6 +1,6 @@
 //! Routines for manipulating the control-flow graph.
 
-use build::CFG;
+use crate::build::CFG;
 use rustc::mir::*;
 
 impl<'tcx> CFG<'tcx> {
diff --git a/src/librustc_mir/build/expr/as_constant.rs b/src/librustc_mir/build/expr/as_constant.rs
index a431bfc61b37a..614668170d5be 100644
--- a/src/librustc_mir/build/expr/as_constant.rs
+++ b/src/librustc_mir/build/expr/as_constant.rs
@@ -1,8 +1,9 @@
 //! See docs in build/expr/mod.rs
 
-use build::Builder;
-use hair::*;
+use crate::build::Builder;
+use crate::hair::*;
 use rustc::mir::*;
+use rustc::ty::CanonicalUserTypeAnnotation;
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     /// Compile `expr`, yielding a compile-time constant. Assumes that
@@ -30,8 +31,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 value,
             } => this.as_constant(value),
             ExprKind::Literal { literal, user_ty } => {
-                let user_ty = user_ty.map(|ty| {
-                    this.canonical_user_type_annotations.push((span, ty))
+                let user_ty = user_ty.map(|user_ty| {
+                    this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
+                        span,
+                        user_ty,
+                        inferred_ty: ty,
+                    })
                 });
                 Constant {
                     span,
diff --git a/src/librustc_mir/build/expr/as_operand.rs b/src/librustc_mir/build/expr/as_operand.rs
index 1f653575a7fbf..38fae8539c8d7 100644
--- a/src/librustc_mir/build/expr/as_operand.rs
+++ b/src/librustc_mir/build/expr/as_operand.rs
@@ -1,8 +1,8 @@
 //! See docs in build/expr/mod.rs
 
-use build::expr::category::Category;
-use build::{BlockAnd, BlockAndExtension, Builder};
-use hair::*;
+use crate::build::expr::category::Category;
+use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::hair::*;
 use rustc::middle::region;
 use rustc::mir::*;
 
diff --git a/src/librustc_mir/build/expr/as_place.rs b/src/librustc_mir/build/expr/as_place.rs
index 3ed00d5797907..ed444191226a1 100644
--- a/src/librustc_mir/build/expr/as_place.rs
+++ b/src/librustc_mir/build/expr/as_place.rs
@@ -1,12 +1,12 @@
 //! See docs in build/expr/mod.rs
 
-use build::expr::category::Category;
-use build::ForGuard::{OutsideGuard, RefWithinGuard};
-use build::{BlockAnd, BlockAndExtension, Builder};
-use hair::*;
+use crate::build::expr::category::Category;
+use crate::build::ForGuard::{OutsideGuard, RefWithinGuard};
+use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::hair::*;
 use rustc::mir::interpret::EvalErrorKind::BoundsCheck;
 use rustc::mir::*;
-use rustc::ty::Variance;
+use rustc::ty::{CanonicalUserTypeAnnotation, Variance};
 
 use rustc_data_structures::indexed_vec::Idx;
 
@@ -134,7 +134,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 let place = unpack!(block = this.as_place(block, source));
                 if let Some(user_ty) = user_ty {
                     let annotation_index = this.canonical_user_type_annotations.push(
-                        (source_info.span, user_ty)
+                        CanonicalUserTypeAnnotation {
+                            span: source_info.span,
+                            user_ty,
+                            inferred_ty: expr.ty,
+                        }
                     );
                     this.cfg.push(
                         block,
@@ -157,7 +161,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 );
                 if let Some(user_ty) = user_ty {
                     let annotation_index = this.canonical_user_type_annotations.push(
-                        (source_info.span, user_ty)
+                        CanonicalUserTypeAnnotation {
+                            span: source_info.span,
+                            user_ty,
+                            inferred_ty: expr.ty,
+                        }
                     );
                     this.cfg.push(
                         block,
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index e0fc90931696e..88dbd93939e54 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -3,13 +3,13 @@
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
 
-use build::expr::category::{Category, RvalueFunc};
-use build::{BlockAnd, BlockAndExtension, Builder};
-use hair::*;
+use crate::build::expr::category::{Category, RvalueFunc};
+use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::hair::*;
 use rustc::middle::region;
 use rustc::mir::interpret::EvalErrorKind;
 use rustc::mir::*;
-use rustc::ty::{self, Ty, UpvarSubsts};
+use rustc::ty::{self, CanonicalUserTypeAnnotation, Ty, UpvarSubsts};
 use syntax_pos::Span;
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
@@ -268,7 +268,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                             span: expr_span,
                             ty: this.hir.tcx().types.u32,
                             user_ty: None,
-                            literal: this.hir.tcx().intern_lazy_const(ty::LazyConst::Evaluated(
+                            literal: this.hir.tcx().mk_lazy_const(ty::LazyConst::Evaluated(
                                 ty::Const::from_bits(
                                     this.hir.tcx(),
                                     0,
@@ -331,8 +331,13 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                         .collect()
                 };
 
+                let inferred_ty = expr.ty;
                 let user_ty = user_ty.map(|ty| {
-                    this.canonical_user_type_annotations.push((expr_span, ty))
+                    this.canonical_user_type_annotations.push(CanonicalUserTypeAnnotation {
+                        span: source_info.span,
+                        user_ty: ty,
+                        inferred_ty,
+                    })
                 });
                 let adt = box AggregateKind::Adt(
                     adt_def,
diff --git a/src/librustc_mir/build/expr/as_temp.rs b/src/librustc_mir/build/expr/as_temp.rs
index df271ff6e4016..efa1a4895e0c0 100644
--- a/src/librustc_mir/build/expr/as_temp.rs
+++ b/src/librustc_mir/build/expr/as_temp.rs
@@ -1,7 +1,7 @@
 //! See docs in build/expr/mod.rs
 
-use build::{BlockAnd, BlockAndExtension, Builder};
-use hair::*;
+use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::hair::*;
 use rustc::middle::region;
 use rustc::mir::*;
 
diff --git a/src/librustc_mir/build/expr/category.rs b/src/librustc_mir/build/expr/category.rs
index 53f84a495696c..ca7d435e62229 100644
--- a/src/librustc_mir/build/expr/category.rs
+++ b/src/librustc_mir/build/expr/category.rs
@@ -1,4 +1,4 @@
-use hair::*;
+use crate::hair::*;
 
 #[derive(Debug, PartialEq)]
 pub enum Category {
diff --git a/src/librustc_mir/build/expr/into.rs b/src/librustc_mir/build/expr/into.rs
index 2ffff68137dd2..05231bc7b3f16 100644
--- a/src/librustc_mir/build/expr/into.rs
+++ b/src/librustc_mir/build/expr/into.rs
@@ -1,8 +1,8 @@
 //! See docs in build/expr/mod.rs
 
-use build::expr::category::{Category, RvalueFunc};
-use build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use hair::*;
+use crate::build::expr::category::{Category, RvalueFunc};
+use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
+use crate::hair::*;
 use rustc::mir::*;
 use rustc::ty;
 
diff --git a/src/librustc_mir/build/expr/stmt.rs b/src/librustc_mir/build/expr/stmt.rs
index 1cbc60586c356..aadc2368f5aec 100644
--- a/src/librustc_mir/build/expr/stmt.rs
+++ b/src/librustc_mir/build/expr/stmt.rs
@@ -1,6 +1,6 @@
-use build::scope::BreakableScope;
-use build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
-use hair::*;
+use crate::build::scope::BreakableScope;
+use crate::build::{BlockAnd, BlockAndExtension, BlockFrame, Builder};
+use crate::hair::*;
 use rustc::mir::*;
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
diff --git a/src/librustc_mir/build/into.rs b/src/librustc_mir/build/into.rs
index 1b29126082067..67b6540febea8 100644
--- a/src/librustc_mir/build/into.rs
+++ b/src/librustc_mir/build/into.rs
@@ -4,11 +4,11 @@
 //! wrapped up as expressions (e.g., blocks). To make this ergonomic, we use this
 //! latter `EvalInto` trait.
 
-use build::{BlockAnd, Builder};
-use hair::*;
+use crate::build::{BlockAnd, Builder};
+use crate::hair::*;
 use rustc::mir::*;
 
-pub(in build) trait EvalInto<'tcx> {
+pub(in crate::build) trait EvalInto<'tcx> {
     fn eval_into<'a, 'gcx>(self,
                            builder: &mut Builder<'a, 'gcx, 'tcx>,
                            destination: &Place<'tcx>,
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index d52ce9a67d29a..96d2c90345933 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -3,13 +3,13 @@
 //! includes the high-level algorithm, the submodules contain the
 //! details.
 
-use build::scope::{CachedBlock, DropKind};
-use build::ForGuard::{self, OutsideGuard, RefWithinGuard, ValWithinGuard};
-use build::{BlockAnd, BlockAndExtension, Builder};
-use build::{GuardFrame, GuardFrameLocal, LocalsForNode};
-use hair::*;
+use crate::build::scope::{CachedBlock, DropKind};
+use crate::build::ForGuard::{self, OutsideGuard, RefWithinGuard, ValWithinGuard};
+use crate::build::{BlockAnd, BlockAndExtension, Builder};
+use crate::build::{GuardFrame, GuardFrameLocal, LocalsForNode};
+use crate::hair::{self, *};
 use rustc::mir::*;
-use rustc::ty::{self, Ty};
+use rustc::ty::{self, CanonicalUserTypeAnnotation, Ty};
 use rustc::ty::layout::VariantIdx;
 use rustc_data_structures::bit_set::BitSet;
 use rustc_data_structures::fx::FxHashMap;
@@ -283,9 +283,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     },
                     ..
                 },
-                user_ty: pat_ascription_ty,
-                variance: _,
-                user_ty_span,
+                ascription: hair::pattern::Ascription {
+                    user_ty: pat_ascription_ty,
+                    variance: _,
+                    user_ty_span,
+                },
             } => {
                 let place =
                     self.storage_live_binding(block, var, irrefutable_pat.span, OutsideGuard);
@@ -303,7 +305,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
                 let ty_source_info = self.source_info(user_ty_span);
                 let user_ty = box pat_ascription_ty.user_ty(
-                    &mut self.canonical_user_type_annotations, ty_source_info.span
+                    &mut self.canonical_user_type_annotations,
+                    place.ty(&self.local_decls, self.hir.tcx()).to_ty(self.hir.tcx()),
+                    ty_source_info.span,
                 );
                 self.cfg.push(
                     block,
@@ -334,6 +338,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 self.schedule_drop_for_binding(var, irrefutable_pat.span, OutsideGuard);
                 block.unit()
             }
+
             _ => {
                 let place = unpack!(block = self.as_place(block, initializer));
                 self.place_into_pattern(block, irrefutable_pat, &place, true)
@@ -530,6 +535,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     self.visit_bindings(subpattern, pattern_user_ty, f);
                 }
             }
+
             PatternKind::Array {
                 ref prefix,
                 ref slice,
@@ -552,15 +558,20 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     self.visit_bindings(subpattern, pattern_user_ty.clone().index(), f);
                 }
             }
+
             PatternKind::Constant { .. } | PatternKind::Range { .. } | PatternKind::Wild => {}
+
             PatternKind::Deref { ref subpattern } => {
                 self.visit_bindings(subpattern, pattern_user_ty.deref(), f);
             }
+
             PatternKind::AscribeUserType {
                 ref subpattern,
-                ref user_ty,
-                user_ty_span,
-                variance: _,
+                ascription: hair::pattern::Ascription {
+                    ref user_ty,
+                    user_ty_span,
+                    variance: _,
+                },
             } => {
                 // This corresponds to something like
                 //
@@ -570,10 +581,14 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 //
                 // Note that the variance doesn't apply here, as we are tracking the effect
                 // of `user_ty` on any bindings contained with subpattern.
-                let annotation = (user_ty_span, user_ty.base);
+                let annotation = CanonicalUserTypeAnnotation {
+                    span: user_ty_span,
+                    user_ty: user_ty.user_ty,
+                    inferred_ty: subpattern.ty,
+                };
                 let projection = UserTypeProjection {
                     base: self.canonical_user_type_annotations.push(annotation),
-                    projs: user_ty.projs.clone(),
+                    projs: Vec::new(),
                 };
                 let subpattern_user_ty = pattern_user_ty.push_projection(&projection, user_ty_span);
                 self.visit_bindings(subpattern, subpattern_user_ty, f)
@@ -721,7 +736,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     ///
     /// The return value is a list of "otherwise" blocks. These are
     /// points in execution where we found that *NONE* of the
-    /// candidates apply.  In principle, this means that the input
+    /// candidates apply. In principle, this means that the input
     /// list was not exhaustive, though at present we sometimes are
     /// not smart enough to recognize all exhaustive inputs.
     ///
@@ -868,7 +883,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// This is the most subtle part of the matching algorithm.  At
+    /// This is the most subtle part of the matching algorithm. At
     /// this point, the input candidates have been fully simplified,
     /// and so we know that all remaining match-pairs require some
     /// sort of test. To decide what test to do, we take the highest
@@ -888,10 +903,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     /// 4. etc.
     ///
     /// Once we know what sort of test we are going to perform, this
-    /// test may also help us with other candidates. So we walk over
+    /// Tests may also help us with other candidates. So we walk over
     /// the candidates (from high to low priority) and check. This
     /// gives us, for each outcome of the test, a transformed list of
-    /// candidates.  For example, if we are testing the current
+    /// candidates. For example, if we are testing the current
     /// variant of `x.0`, and we have a candidate `{x.0 @ Some(v), x.1
     /// @ 22}`, then we would have a resulting candidate of `{(x.0 as
     /// Some).0 @ v, x.1 @ 22}`. Note that the first match-pair is now
@@ -1087,7 +1102,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     /// for the case where the guard fails.
     ///
     /// Note: we check earlier that if there is a guard, there cannot
-    /// be move bindings.  This isn't really important for the
+    /// be move bindings. This isn't really important for the
     /// self-consistency of this fn, but the reason for it should be
     /// clear: after we've done the assignments, if there were move
     /// bindings, further tests would be a use-after-move (which would
@@ -1337,7 +1352,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             );
 
             let user_ty = box ascription.user_ty.clone().user_ty(
-                &mut self.canonical_user_type_annotations, source_info.span
+                &mut self.canonical_user_type_annotations,
+                ascription.source.ty(&self.local_decls, self.hir.tcx()).to_ty(self.hir.tcx()),
+                source_info.span
             );
             self.cfg.push(
                 block,
diff --git a/src/librustc_mir/build/matches/simplify.rs b/src/librustc_mir/build/matches/simplify.rs
index 22bc3506803f2..01f8cbfbe8e2b 100644
--- a/src/librustc_mir/build/matches/simplify.rs
+++ b/src/librustc_mir/build/matches/simplify.rs
@@ -12,9 +12,9 @@
 //! sort of test: for example, testing which variant an enum is, or
 //! testing a value against a constant.
 
-use build::Builder;
-use build::matches::{Ascription, Binding, MatchPair, Candidate};
-use hair::*;
+use crate::build::Builder;
+use crate::build::matches::{Ascription, Binding, MatchPair, Candidate};
+use crate::hair::{self, *};
 use rustc::ty;
 use rustc::ty::layout::{Integer, IntegerExt, Size};
 use syntax::attr::{SignedInt, UnsignedInt};
@@ -45,10 +45,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Tries to simplify `match_pair`, returning true if
+    /// Tries to simplify `match_pair`, returning `Ok(())` if
     /// successful. If successful, new match pairs and bindings will
     /// have been pushed into the candidate. If no simplification is
-    /// possible, Err is returned and no changes are made to
+    /// possible, `Err` is returned and no changes are made to
     /// candidate.
     fn simplify_match_pair<'pat>(&mut self,
                                  match_pair: MatchPair<'pat, 'tcx>,
@@ -58,9 +58,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         match *match_pair.pattern.kind {
             PatternKind::AscribeUserType {
                 ref subpattern,
-                variance,
-                ref user_ty,
-                user_ty_span
+                ascription: hair::pattern::Ascription {
+                    variance,
+                    ref user_ty,
+                    user_ty_span,
+                },
             } => {
                 // Apply the type ascription to the value at `match_pair.place`, which is the
                 // value being matched, taking the variance field into account.
@@ -106,27 +108,34 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             }
 
             PatternKind::Range(PatternRange { lo, hi, ty, end }) => {
-                let range = match ty.sty {
+                let (range, bias) = match ty.sty {
                     ty::Char => {
-                        Some(('\u{0000}' as u128, '\u{10FFFF}' as u128, Size::from_bits(32)))
+                        (Some(('\u{0000}' as u128, '\u{10FFFF}' as u128, Size::from_bits(32))), 0)
                     }
                     ty::Int(ity) => {
                         // FIXME(49937): refactor these bit manipulations into interpret.
                         let size = Integer::from_attr(&tcx, SignedInt(ity)).size();
-                        let min = 1u128 << (size.bits() - 1);
-                        let max = (1u128 << (size.bits() - 1)) - 1;
-                        Some((min, max, size))
+                        let max = !0u128 >> (128 - size.bits());
+                        let bias = 1u128 << (size.bits() - 1);
+                        (Some((0, max, size)), bias)
                     }
                     ty::Uint(uty) => {
                         // FIXME(49937): refactor these bit manipulations into interpret.
                         let size = Integer::from_attr(&tcx, UnsignedInt(uty)).size();
                         let max = !0u128 >> (128 - size.bits());
-                        Some((0, max, size))
+                        (Some((0, max, size)), 0)
                     }
-                    _ => None,
+                    _ => (None, 0),
                 };
                 if let Some((min, max, sz)) = range {
                     if let (Some(lo), Some(hi)) = (lo.val.try_to_bits(sz), hi.val.try_to_bits(sz)) {
+                        // We want to compare ranges numerically, but the order of the bitwise
+                        // representation of signed integers does not match their numeric order.
+                        // Thus, to correct the ordering, we need to shift the range of signed
+                        // integers to correct the comparison. This is achieved by XORing with a
+                        // bias (see pattern/_match.rs for another pertinent example of this
+                        // pattern).
+                        let (lo, hi) = (lo ^ bias, hi ^ bias);
                         if lo <= min && (hi > max || hi == max && end == RangeEnd::Included) {
                             // Irrefutable pattern match.
                             return Ok(());
@@ -165,7 +174,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 } else {
                     Err(match_pair)
                 }
-            },
+            }
 
             PatternKind::Array { ref prefix, ref slice, ref suffix } => {
                 self.prefix_slice_suffix(&mut candidate.match_pairs,
diff --git a/src/librustc_mir/build/matches/test.rs b/src/librustc_mir/build/matches/test.rs
index 696c173b048ad..a41d3895d6d3c 100644
--- a/src/librustc_mir/build/matches/test.rs
+++ b/src/librustc_mir/build/matches/test.rs
@@ -5,10 +5,10 @@
 // identify what tests are needed, perform the tests, and then filter
 // the candidates based on the result.
 
-use build::Builder;
-use build::matches::{Candidate, MatchPair, Test, TestKind};
-use hair::*;
-use hair::pattern::compare_const_vals;
+use crate::build::Builder;
+use crate::build::matches::{Candidate, MatchPair, Test, TestKind};
+use crate::hair::*;
+use crate::hair::pattern::compare_const_vals;
 use rustc_data_structures::bit_set::BitSet;
 use rustc_data_structures::fx::FxHashMap;
 use rustc::ty::{self, Ty};
@@ -35,10 +35,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 }
             }
 
-            PatternKind::Constant { .. }
-            if is_switch_ty(match_pair.pattern.ty) => {
-                // for integers, we use a SwitchInt match, which allows
-                // us to handle more cases
+            PatternKind::Constant { .. } if is_switch_ty(match_pair.pattern.ty) => {
+                // For integers, we use a `SwitchInt` match, which allows
+                // us to handle more cases.
                 Test {
                     span: match_pair.pattern.span,
                     kind: TestKind::SwitchInt {
@@ -253,12 +252,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             TestKind::Eq { value, mut ty } => {
                 let val = Operand::Copy(place.clone());
                 let mut expect = self.literal_operand(test.span, ty, value);
-                // Use PartialEq::eq instead of BinOp::Eq
+                // Use `PartialEq::eq` instead of `BinOp::Eq`
                 // (the binop can only handle primitives)
                 let fail = self.cfg.start_new_block();
                 if !ty.is_scalar() {
-                    // If we're using b"..." as a pattern, we need to insert an
-                    // unsizing coercion, as the byte string has the type &[u8; N].
+                    // If we're using `b"..."` as a pattern, we need to insert an
+                    // unsizing coercion, as the byte string has the type `&[u8; N]`.
                     //
                     // We want to do this even when the scrutinee is a reference to an
                     // array, so we can call `<[u8]>::eq` rather than having to find an
@@ -302,7 +301,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     }
                     let eq_def_id = self.hir.tcx().lang_items().eq_trait().unwrap();
                     let (mty, method) = self.hir.trait_method(eq_def_id, "eq", ty, &[ty.into()]);
-                    let method = self.hir.tcx().intern_lazy_const(ty::LazyConst::Evaluated(method));
+                    let method = self.hir.tcx().mk_lazy_const(ty::LazyConst::Evaluated(method));
 
                     let re_erased = self.hir.tcx().types.re_erased;
                     // take the argument by reference
@@ -443,7 +442,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
     /// appropriate.
     ///
     /// So, for example, if this candidate is `x @ Some(P0)` and the
-    /// test is a variant test, then we would add `(x as Option).0 @
+    /// Tests is a variant test, then we would add `(x as Option).0 @
     /// P0` to the `resulting_candidates` entry corresponding to the
     /// variant `Some`.
     ///
@@ -503,6 +502,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 resulting_candidates[variant_index.as_usize()].push(new_candidate);
                 true
             }
+
             (&TestKind::Switch { .. }, _) => false,
 
             // If we are performing a switch over integers, then this informs integer
@@ -539,7 +539,6 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
             (&TestKind::SwitchInt { .. }, _) => false,
 
-
             (&TestKind::Len { len: test_len, op: BinOp::Eq },
              &PatternKind::Slice { ref prefix, ref slice, ref suffix }) => {
                 let pat_len = (prefix.len() + suffix.len()) as u64;
diff --git a/src/librustc_mir/build/matches/util.rs b/src/librustc_mir/build/matches/util.rs
index b5a1a388e9cbc..b583b184a4103 100644
--- a/src/librustc_mir/build/matches/util.rs
+++ b/src/librustc_mir/build/matches/util.rs
@@ -1,6 +1,6 @@
-use build::Builder;
-use build::matches::MatchPair;
-use hair::*;
+use crate::build::Builder;
+use crate::build::matches::MatchPair;
+use crate::hair::*;
 use rustc::mir::*;
 use std::u32;
 use std::convert::TryInto;
@@ -13,7 +13,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         subpatterns.iter()
                    .map(|fieldpat| {
                        let place = place.clone().field(fieldpat.field,
-                                                         fieldpat.pattern.ty);
+                                                       fieldpat.pattern.ty);
                        MatchPair::new(place, &fieldpat.pattern)
                    })
                    .collect()
diff --git a/src/librustc_mir/build/misc.rs b/src/librustc_mir/build/misc.rs
index c849c02242840..900f7f1744a13 100644
--- a/src/librustc_mir/build/misc.rs
+++ b/src/librustc_mir/build/misc.rs
@@ -1,7 +1,7 @@
 //! Miscellaneous builder routines that are not specific to building any particular
 //! kind of thing.
 
-use build::Builder;
+use crate::build::Builder;
 
 use rustc::ty::{self, Ty};
 
@@ -9,7 +9,7 @@ use rustc::mir::*;
 use syntax_pos::{Span, DUMMY_SP};
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
-    /// Add a new temporary value of type `ty` storing the result of
+    /// Adds a new temporary value of type `ty` storing the result of
     /// evaluating `expr`.
     ///
     /// N.B., **No cleanup is scheduled for this temporary.** You should
@@ -33,7 +33,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             span,
             ty,
             user_ty: None,
-            literal: self.hir.tcx().intern_lazy_const(ty::LazyConst::Evaluated(literal)),
+            literal: self.hir.tcx().mk_lazy_const(ty::LazyConst::Evaluated(literal)),
         };
         Operand::Constant(constant)
     }
diff --git a/src/librustc_mir/build/mod.rs b/src/librustc_mir/build/mod.rs
index 2bf2824d835cc..64ab491cbd5b0 100644
--- a/src/librustc_mir/build/mod.rs
+++ b/src/librustc_mir/build/mod.rs
@@ -1,7 +1,10 @@
-use build;
-use build::scope::{CachedBlock, DropKind};
-use hair::cx::Cx;
-use hair::{LintLevel, BindingMode, PatternKind};
+use crate::build;
+use crate::build::scope::{CachedBlock, DropKind};
+use crate::hair::cx::Cx;
+use crate::hair::{LintLevel, BindingMode, PatternKind};
+use crate::shim;
+use crate::transform::MirSource;
+use crate::util as mir_util;
 use rustc::hir;
 use rustc::hir::Node;
 use rustc::hir::def_id::DefId;
@@ -13,7 +16,6 @@ use rustc::ty::subst::Substs;
 use rustc::util::nodemap::NodeMap;
 use rustc_target::spec::PanicStrategy;
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
-use shim;
 use std::mem;
 use std::u32;
 use rustc_target::spec::abi::Abi;
@@ -21,12 +23,10 @@ use syntax::ast;
 use syntax::attr::{self, UnwindAttr};
 use syntax::symbol::keywords;
 use syntax_pos::Span;
-use transform::MirSource;
-use util as mir_util;
 
 use super::lints;
 
-/// Construct the MIR for a given def-id.
+/// Construct the MIR for a given `DefId`.
 pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'tcx> {
     let id = tcx.hir().as_local_node_id(def_id).unwrap();
 
@@ -64,8 +64,8 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
         ) => {
             (*body_id, ty.span)
         }
-        Node::AnonConst(hir::AnonConst { body, id, .. }) => {
-            (*body, tcx.hir().span(*id))
+        Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
+            (*body, tcx.hir().span_by_hir_id(*hir_id))
         }
 
         _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def_id),
@@ -75,7 +75,7 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
         let cx = Cx::new(&infcx, id);
         let mut mir = if cx.tables().tainted_by_errors {
             build::construct_error(cx, body_id)
-        } else if let hir::BodyOwnerKind::Fn = cx.body_owner_kind {
+        } else if cx.body_owner_kind.is_fn_or_closure() {
             // fetch the fully liberated fn signature (that is, all bound
             // types/lifetimes replaced)
             let fn_hir_id = tcx.hir().node_to_hir_id(id);
@@ -92,7 +92,7 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
                     Some(ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None))
                 }
                 ty::Generator(..) => {
-                    let gen_ty = tcx.body_tables(body_id).node_id_to_type(fn_hir_id);
+                    let gen_ty = tcx.body_tables(body_id).node_type(fn_hir_id);
                     Some(ArgInfo(gen_ty, None, None, None))
                 }
                 _ => None,
@@ -114,7 +114,7 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
                         let self_arg;
                         if let Some(ref fn_decl) = tcx.hir().fn_decl(owner_id) {
                             let ty_hir_id = fn_decl.inputs[index].hir_id;
-                            let ty_span = tcx.hir().span(tcx.hir().hir_to_node_id(ty_hir_id));
+                            let ty_span = tcx.hir().span_by_hir_id(ty_hir_id);
                             opt_ty_info = Some(ty_span);
                             self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
                                 match fn_decl.implicit_self {
@@ -161,7 +161,7 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
         };
         globalizer.visit_mir(&mut mir);
         let mir = unsafe {
-            mem::transmute::<Mir, Mir<'tcx>>(mir)
+            mem::transmute::<Mir<'_>, Mir<'tcx>>(mir)
         };
 
         mir_util::dump_mir(tcx, None, "mir_map", &0,
@@ -173,9 +173,9 @@ pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'t
     })
 }
 
-/// A pass to lift all the types and substitutions in a Mir
+/// A pass to lift all the types and substitutions in a MIR
 /// to the global tcx. Sadly, we don't have a "folder" that
-/// can change 'tcx so we have to transmute afterwards.
+/// can change `'tcx` so we have to transmute afterwards.
 struct GlobalizeMir<'a, 'gcx: 'a> {
     tcx: TyCtxt<'a, 'gcx, 'gcx>,
     span: Span
@@ -229,7 +229,7 @@ fn create_constructor_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                      -> Mir<'tcx>
 {
     let span = tcx.hir().span(ctor_id);
-    if let hir::VariantData::Tuple(ref fields, ctor_id) = *v {
+    if let hir::VariantData::Tuple(ref fields, ctor_id, _) = *v {
         tcx.infer_ctxt().enter(|infcx| {
             let mut mir = shim::build_adt_ctor(&infcx, ctor_id, fields, span);
 
@@ -241,7 +241,7 @@ fn create_constructor_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             };
             globalizer.visit_mir(&mut mir);
             let mir = unsafe {
-                mem::transmute::<Mir, Mir<'tcx>>(mir)
+                mem::transmute::<Mir<'_>, Mir<'tcx>>(mir)
             };
 
             mir_util::dump_mir(tcx, None, "mir_map", &0,
@@ -263,7 +263,7 @@ fn liberated_closure_env_ty<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                             body_id: hir::BodyId)
                                             -> Ty<'tcx> {
     let closure_expr_hir_id = tcx.hir().node_to_hir_id(closure_expr_id);
-    let closure_ty = tcx.body_tables(body_id).node_id_to_type(closure_expr_hir_id);
+    let closure_ty = tcx.body_tables(body_id).node_type(closure_expr_hir_id);
 
     let (closure_def_id, closure_substs) = match closure_ty.sty {
         ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
@@ -335,47 +335,47 @@ struct Builder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     fn_span: Span,
     arg_count: usize,
 
-    /// the current set of scopes, updated as we traverse;
-    /// see the `scope` module for more details
+    /// The current set of scopes, updated as we traverse;
+    /// see the `scope` module for more details.
     scopes: Vec<scope::Scope<'tcx>>,
 
-    /// the block-context: each time we build the code within an hair::Block,
+    /// The block-context: each time we build the code within an hair::Block,
     /// we push a frame here tracking whether we are building a statement or
     /// if we are pushing the tail expression of the block. This is used to
     /// embed information in generated temps about whether they were created
     /// for a block tail expression or not.
     ///
     /// It would be great if we could fold this into `self.scopes`
-    /// somehow; but right now I think that is very tightly tied to
+    /// somehow, but right now I think that is very tightly tied to
     /// the code generation in ways that we cannot (or should not)
     /// start just throwing new entries onto that vector in order to
     /// distinguish the context of EXPR1 from the context of EXPR2 in
-    /// `{ STMTS; EXPR1 } + EXPR2`
+    /// `{ STMTS; EXPR1 } + EXPR2`.
     block_context: BlockContext,
 
     /// The current unsafe block in scope, even if it is hidden by
-    /// a PushUnsafeBlock
+    /// a `PushUnsafeBlock`.
     unpushed_unsafe: Safety,
 
-    /// The number of `push_unsafe_block` levels in scope
+    /// The number of `push_unsafe_block` levels in scope.
     push_unsafe_count: usize,
 
-    /// the current set of breakables; see the `scope` module for more
-    /// details
+    /// The current set of breakables; see the `scope` module for more
+    /// details.
     breakable_scopes: Vec<scope::BreakableScope<'tcx>>,
 
-    /// the vector of all scopes that we have created thus far;
-    /// we track this for debuginfo later
+    /// The vector of all scopes that we have created thus far;
+    /// we track this for debuginfo later.
     source_scopes: IndexVec<SourceScope, SourceScopeData>,
     source_scope_local_data: IndexVec<SourceScope, SourceScopeLocalData>,
     source_scope: SourceScope,
 
-    /// the guard-context: each time we build the guard expression for
+    /// The guard-context: each time we build the guard expression for
     /// a match arm, we push onto this stack, and then pop when we
     /// finish building it.
     guard_context: Vec<GuardFrame>,
 
-    /// Maps node ids of variable bindings to the `Local`s created for them.
+    /// Maps `NodeId`s of variable bindings to the `Local`s created for them.
     /// (A match binding can have two locals; the 2nd is for the arm's guard.)
     var_indices: NodeMap<LocalsForNode>,
     local_decls: IndexVec<Local, LocalDecl<'tcx>>,
@@ -383,12 +383,12 @@ struct Builder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     upvar_decls: Vec<UpvarDecl>,
     unit_temp: Option<Place<'tcx>>,
 
-    /// cached block with the RESUME terminator; this is created
+    /// Cached block with the `RESUME` terminator; this is created
     /// when first set of cleanups are built.
     cached_resume_block: Option<BasicBlock>,
-    /// cached block with the RETURN terminator
+    /// Cached block with the `RETURN` terminator.
     cached_return_block: Option<BasicBlock>,
-    /// cached block with the UNREACHABLE terminator
+    /// Cached block with the `UNREACHABLE` terminator.
     cached_unreachable_block: Option<BasicBlock>,
 }
 
@@ -407,7 +407,7 @@ impl BlockContext {
     fn push(&mut self, bf: BlockFrame) { self.0.push(bf); }
     fn pop(&mut self) -> Option<BlockFrame> { self.0.pop() }
 
-    /// Traverses the frames on the BlockContext, searching for either
+    /// Traverses the frames on the `BlockContext`, searching for either
     /// the first block-tail expression frame with no intervening
     /// statement frame.
     ///
@@ -453,13 +453,13 @@ impl BlockContext {
 
 #[derive(Debug)]
 enum LocalsForNode {
-    /// In the usual case, a node-id for an identifier maps to at most
-    /// one Local declaration.
+    /// In the usual case, a `NodeId` for an identifier maps to at most
+    /// one `Local` declaration.
     One(Local),
 
     /// The exceptional case is identifiers in a match arm's pattern
     /// that are referenced in a guard of that match arm. For these,
-    /// we can have `2+k` Locals, where `k` is the number of candidate
+    /// we can have `2 + k` Locals, where `k` is the number of candidate
     /// patterns (separated by `|`) in the arm.
     ///
     /// * `for_arm_body` is the Local used in the arm body (which is
@@ -505,11 +505,11 @@ struct GuardFrame {
     ///      P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
     /// }
     ///
-    /// here, when building for FIXME
+    /// here, when building for FIXME.
     locals: Vec<GuardFrameLocal>,
 }
 
-/// ForGuard indicates whether we are talking about:
+/// `ForGuard` indicates whether we are talking about:
 ///   1. the temp for a local binding used solely within guard expressions,
 ///   2. the temp that holds reference to (1.), which is actually what the
 ///      guard expressions see, or
@@ -671,7 +671,7 @@ fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>,
                 mutability: Mutability::Not,
             };
             if let Some(Node::Binding(pat)) = tcx_hir.find(var_node_id) {
-                if let hir::PatKind::Binding(_, _, ident, _) = pat.node {
+                if let hir::PatKind::Binding(_, _, _, ident, _) = pat.node {
                     decl.debug_name = ident.name;
                     if let Some(&bm) = hir.tables.pat_binding_modes().get(pat.hir_id) {
                         if bm == ty::BindByValue(hir::MutMutable) {
@@ -877,8 +877,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             let mut name = None;
             if let Some(pat) = pattern {
                 match pat.node {
-                    hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ident, _)
-                    | hir::PatKind::Binding(hir::BindingAnnotation::Mutable, _, ident, _) => {
+                    hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, _, ident, _)
+                    | hir::PatKind::Binding(hir::BindingAnnotation::Mutable, _, _, ident, _) => {
                         name = Some(ident.name);
                     }
                     _ => (),
diff --git a/src/librustc_mir/build/scope.rs b/src/librustc_mir/build/scope.rs
index b44c2cc9c166a..3392495f7a11b 100644
--- a/src/librustc_mir/build/scope.rs
+++ b/src/librustc_mir/build/scope.rs
@@ -77,8 +77,8 @@ should go to.
 
 */
 
-use build::{BlockAnd, BlockAndExtension, Builder, CFG};
-use hair::LintLevel;
+use crate::build::{BlockAnd, BlockAndExtension, Builder, CFG};
+use crate::hair::LintLevel;
 use rustc::middle::region;
 use rustc::ty::Ty;
 use rustc::hir;
@@ -210,7 +210,7 @@ impl DropKind {
 }
 
 impl<'tcx> Scope<'tcx> {
-    /// Invalidate all the cached blocks in the scope.
+    /// Invalidates all the cached blocks in the scope.
     ///
     /// Should always be run for all inner scopes when a drop is pushed into some scope enclosing a
     /// larger extent of code.
@@ -390,7 +390,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
 
 
     /// Branch out of `block` to `target`, exiting all scopes up to
-    /// and including `region_scope`.  This will insert whatever drops are
+    /// and including `region_scope`. This will insert whatever drops are
     /// needed. See module comment for details.
     pub fn exit_scope(&mut self,
                       span: Span,
@@ -613,6 +613,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             hir::BodyOwnerKind::Static(_) =>
                 // No need to free storage in this context.
                 None,
+            hir::BodyOwnerKind::Closure |
             hir::BodyOwnerKind::Fn =>
                 Some(self.topmost_scope()),
         }
@@ -845,7 +846,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
         next_target.unit()
     }
 
-    /// Create an Assert terminator and return the success block.
+    /// Creates an Assert terminator and return the success block.
     /// If the boolean condition operand is not the expected value,
     /// a runtime panic will be caused with the given message.
     pub fn assert(&mut self, block: BasicBlock,
diff --git a/src/librustc_mir/const_eval.rs b/src/librustc_mir/const_eval.rs
index f5f4048167938..7be7f4b439289 100644
--- a/src/librustc_mir/const_eval.rs
+++ b/src/librustc_mir/const_eval.rs
@@ -10,11 +10,10 @@ use rustc::hir::{self, def_id::DefId};
 use rustc::hir::def::Def;
 use rustc::mir::interpret::{ConstEvalErr, ErrorHandled};
 use rustc::mir;
-use rustc::ty::{self, TyCtxt, Instance, query::TyCtxtAt};
-use rustc::ty::layout::{self, LayoutOf, TyLayout, VariantIdx};
+use rustc::ty::{self, TyCtxt, query::TyCtxtAt};
+use rustc::ty::layout::{self, LayoutOf, VariantIdx};
 use rustc::ty::subst::Subst;
 use rustc::traits::Reveal;
-use rustc_data_structures::indexed_vec::IndexVec;
 use rustc_data_structures::fx::FxHashMap;
 use rustc::util::common::ErrorReported;
 
@@ -22,7 +21,8 @@ use syntax::ast::Mutability;
 use syntax::source_map::{Span, DUMMY_SP};
 
 use crate::interpret::{self,
-    PlaceTy, MPlaceTy, MemPlace, OpTy, Operand, Immediate, Scalar, RawConst, ConstValue, Pointer,
+    PlaceTy, MPlaceTy, MemPlace, OpTy, ImmTy, Operand, Immediate, Scalar, Pointer,
+    RawConst, ConstValue,
     EvalResult, EvalError, EvalErrorKind, GlobalId, EvalContext, StackPopCleanup,
     Allocation, AllocId, MemoryKind,
     snapshot, RefTracking,
@@ -35,71 +35,20 @@ const STEPS_UNTIL_DETECTOR_ENABLED: isize = 1_000_000;
 /// Should be a power of two for performance reasons.
 const DETECTOR_SNAPSHOT_PERIOD: isize = 256;
 
-/// Warning: do not use this function if you expect to start interpreting the given `Mir`.
-/// The `EvalContext` is only meant to be used to query values from constants and statics.
-///
-/// This function is used during const propagation. We cannot use `mk_eval_cx`, because copy
-/// propagation happens *during* the computation of the MIR of the current function. So if we
-/// tried to call the `optimized_mir` query, we'd get a cycle error because we are (transitively)
-/// inside the `optimized_mir` query of the `Instance` given.
-///
-/// Since we are looking at the MIR of the function in an abstract manner, we don't have a
-/// `ParamEnv` available to us. This function creates a `ParamEnv` for the given instance.
-pub fn mk_borrowck_eval_cx<'a, 'mir, 'tcx>(
-    tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    instance: Instance<'tcx>,
-    mir: &'mir mir::Mir<'tcx>,
-    span: Span,
-) -> EvalResult<'tcx, CompileTimeEvalContext<'a, 'mir, 'tcx>> {
-    debug!("mk_borrowck_eval_cx: {:?}", instance);
-    let param_env = tcx.param_env(instance.def_id());
-    mk_eval_cx_inner(tcx, instance, mir, span, param_env)
-}
-
-/// This is just a helper function to reduce code duplication between `mk_borrowck_eval_cx` and
-/// `mk_eval_cx`. Do not call this function directly.
-fn mk_eval_cx_inner<'a, 'mir, 'tcx>(
-    tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    instance: Instance<'tcx>,
-    mir: &'mir mir::Mir<'tcx>,
-    span: Span,
-    param_env: ty::ParamEnv<'tcx>,
-) -> EvalResult<'tcx, CompileTimeEvalContext<'a, 'mir, 'tcx>> {
-    let mut ecx = EvalContext::new(tcx.at(span), param_env, CompileTimeInterpreter::new());
-    // Insert a stack frame so any queries have the correct substs.
-    // We also avoid all the extra work performed by push_stack_frame,
-    // like initializing local variables
-    ecx.stack.push(interpret::Frame {
-        block: mir::START_BLOCK,
-        locals: IndexVec::new(),
-        instance,
-        span,
-        mir,
-        return_place: None,
-        return_to_block: StackPopCleanup::Goto(None), // never pop
-        stmt: 0,
-        extra: (),
-    });
-    Ok(ecx)
-}
-
-/// Warning: do not use this function if you expect to start interpreting the given `Mir`.
 /// The `EvalContext` is only meant to be used to do field and index projections into constants for
 /// `simd_shuffle` and const patterns in match arms.
 ///
 /// The function containing the `match` that is currently being analyzed may have generic bounds
-/// that inform us about the generic bounds of the constant. E.g. using an associated constant
+/// that inform us about the generic bounds of the constant. E.g., using an associated constant
 /// of a function's generic parameter will require knowledge about the bounds on the generic
 /// parameter. These bounds are passed to `mk_eval_cx` via the `ParamEnv` argument.
-fn mk_eval_cx<'a, 'tcx>(
+pub(crate) fn mk_eval_cx<'a, 'mir, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    instance: Instance<'tcx>,
+    span: Span,
     param_env: ty::ParamEnv<'tcx>,
-) -> EvalResult<'tcx, CompileTimeEvalContext<'a, 'tcx, 'tcx>> {
-    debug!("mk_eval_cx: {:?}, {:?}", instance, param_env);
-    let span = tcx.def_span(instance.def_id());
-    let mir = tcx.optimized_mir(instance.def.def_id());
-    mk_eval_cx_inner(tcx, instance, mir, span, param_env)
+) -> CompileTimeEvalContext<'a, 'mir, 'tcx> {
+    debug!("mk_eval_cx: {:?}", param_env);
+    EvalContext::new(tcx.at(span), param_env, CompileTimeInterpreter::new())
 }
 
 pub(crate) fn eval_promoted<'a, 'mir, 'tcx>(
@@ -108,7 +57,8 @@ pub(crate) fn eval_promoted<'a, 'mir, 'tcx>(
     mir: &'mir mir::Mir<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
 ) -> EvalResult<'tcx, MPlaceTy<'tcx>> {
-    let mut ecx = mk_borrowck_eval_cx(tcx, cid.instance, mir, DUMMY_SP).unwrap();
+    let span = tcx.def_span(cid.instance.def_id());
+    let mut ecx = mk_eval_cx(tcx, span, param_env);
     eval_body_using_ecx(&mut ecx, cid, Some(mir), param_env)
 }
 
@@ -118,20 +68,17 @@ pub fn op_to_const<'tcx>(
     op: OpTy<'tcx>,
     may_normalize: bool,
 ) -> EvalResult<'tcx, ty::Const<'tcx>> {
-    // We do not normalize just any data.  Only scalar layout and fat pointers.
+    // We do not normalize just any data.  Only scalar layout and slices.
     let normalize = may_normalize
         && match op.layout.abi {
             layout::Abi::Scalar(..) => true,
-            layout::Abi::ScalarPair(..) => {
-                // Must be a fat pointer
-                op.layout.ty.builtin_deref(true).is_some()
-            },
+            layout::Abi::ScalarPair(..) => op.layout.ty.is_slice(),
             _ => false,
         };
     let normalized_op = if normalize {
         ecx.try_read_immediate(op)?
     } else {
-        match op.op {
+        match *op {
             Operand::Indirect(mplace) => Err(mplace),
             Operand::Immediate(val) => Ok(val)
         }
@@ -154,20 +101,11 @@ pub fn op_to_const<'tcx>(
         Ok(Immediate::Scalar(x)) =>
             ConstValue::Scalar(x.not_undef()?),
         Ok(Immediate::ScalarPair(a, b)) =>
-            ConstValue::ScalarPair(a.not_undef()?, b.not_undef()?),
+            ConstValue::Slice(a.not_undef()?, b.to_usize(ecx)?),
     };
     Ok(ty::Const { val, ty: op.layout.ty })
 }
 
-pub fn lazy_const_to_op<'tcx>(
-    ecx: &CompileTimeEvalContext<'_, '_, 'tcx>,
-    cnst: ty::LazyConst<'tcx>,
-    ty: ty::Ty<'tcx>,
-) -> EvalResult<'tcx, OpTy<'tcx>> {
-    let op = ecx.const_value_to_op(cnst)?;
-    Ok(OpTy { op, layout: ecx.layout_of(ty)? })
-}
-
 fn eval_body_and_ecx<'a, 'mir, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     cid: GlobalId<'tcx>,
@@ -244,7 +182,7 @@ enum ConstEvalError {
 }
 
 impl fmt::Display for ConstEvalError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use self::ConstEvalError::*;
         match *self {
             NeedsRfc(ref msg) => {
@@ -391,19 +329,22 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
         ret: Option<mir::BasicBlock>,
     ) -> EvalResult<'tcx, Option<&'mir mir::Mir<'tcx>>> {
         debug!("eval_fn_call: {:?}", instance);
-        // Execution might have wandered off into other crates, so we cannot to a stability-
-        // sensitive check here.  But we can at least rule out functions that are not const
-        // at all.
-        if !ecx.tcx.is_const_fn_raw(instance.def_id()) {
-            // Some functions we support even if they are non-const -- but avoid testing
-            // that for const fn!  We certainly do *not* want to actually call the fn
-            // though, so be sure we return here.
-            return if ecx.hook_fn(instance, args, dest)? {
-                ecx.goto_block(ret)?; // fully evaluated and done
-                Ok(None)
-            } else {
-                err!(MachineError(format!("calling non-const function `{}`", instance)))
-            };
+        // Only check non-glue functions
+        if let ty::InstanceDef::Item(def_id) = instance.def {
+            // Execution might have wandered off into other crates, so we cannot to a stability-
+            // sensitive check here.  But we can at least rule out functions that are not const
+            // at all.
+            if !ecx.tcx.is_const_fn_raw(def_id) {
+                // Some functions we support even if they are non-const -- but avoid testing
+                // that for const fn!  We certainly do *not* want to actually call the fn
+                // though, so be sure we return here.
+                return if ecx.hook_fn(instance, args, dest)? {
+                    ecx.goto_block(ret)?; // fully evaluated and done
+                    Ok(None)
+                } else {
+                    err!(MachineError(format!("calling non-const function `{}`", instance)))
+                };
+            }
         }
         // This is a const fn. Call it.
         Ok(Some(match ecx.load_mir(instance.def) {
@@ -439,10 +380,8 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
     fn ptr_op(
         _ecx: &EvalContext<'a, 'mir, 'tcx, Self>,
         _bin_op: mir::BinOp,
-        _left: Scalar,
-        _left_layout: TyLayout<'tcx>,
-        _right: Scalar,
-        _right_layout: TyLayout<'tcx>,
+        _left: ImmTy<'tcx>,
+        _right: ImmTy<'tcx>,
     ) -> EvalResult<'tcx, (Scalar, bool)> {
         Err(
             ConstEvalError::NeedsRfc("pointer arithmetic or comparison".to_string()).into(),
@@ -515,7 +454,7 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
         Ok(())
     }
 
-    /// Called immediately before a stack frame gets popped
+    /// Called immediately before a stack frame gets popped.
     #[inline(always)]
     fn stack_pop(
         _ecx: &mut EvalContext<'a, 'mir, 'tcx, Self>,
@@ -525,20 +464,19 @@ impl<'a, 'mir, 'tcx> interpret::Machine<'a, 'mir, 'tcx>
     }
 }
 
-/// Project to a field of a (variant of a) const
+/// Projects to a field of a (variant of a) const.
 pub fn const_field<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    instance: ty::Instance<'tcx>,
     variant: Option<VariantIdx>,
     field: mir::Field,
     value: ty::Const<'tcx>,
 ) -> ::rustc::mir::interpret::ConstEvalResult<'tcx> {
-    trace!("const_field: {:?}, {:?}, {:?}", instance, field, value);
-    let ecx = mk_eval_cx(tcx, instance, param_env).unwrap();
+    trace!("const_field: {:?}, {:?}", field, value);
+    let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env);
     let result = (|| {
         // get the operand again
-        let op = lazy_const_to_op(&ecx, ty::LazyConst::Evaluated(value), value.ty)?;
+        let op = ecx.lazy_const_to_op(ty::LazyConst::Evaluated(value), value.ty)?;
         // downcast
         let down = match variant {
             None => op,
@@ -560,12 +498,11 @@ pub fn const_field<'a, 'tcx>(
 pub fn const_variant_index<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    instance: ty::Instance<'tcx>,
     val: ty::Const<'tcx>,
 ) -> EvalResult<'tcx, VariantIdx> {
-    trace!("const_variant_index: {:?}, {:?}", instance, val);
-    let ecx = mk_eval_cx(tcx, instance, param_env).unwrap();
-    let op = lazy_const_to_op(&ecx, ty::LazyConst::Evaluated(val), val.ty)?;
+    trace!("const_variant_index: {:?}", val);
+    let ecx = mk_eval_cx(tcx, DUMMY_SP, param_env);
+    let op = ecx.lazy_const_to_op(ty::LazyConst::Evaluated(val), val.ty)?;
     Ok(ecx.read_discriminant(op)?.1)
 }
 
@@ -584,7 +521,7 @@ fn validate_and_turn_into_const<'a, 'tcx>(
     key: ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>,
 ) -> ::rustc::mir::interpret::ConstEvalResult<'tcx> {
     let cid = key.value;
-    let ecx = mk_eval_cx(tcx, cid.instance, key.param_env).unwrap();
+    let ecx = mk_eval_cx(tcx, tcx.def_span(key.value.instance.def_id()), key.param_env);
     let val = (|| {
         let op = ecx.raw_const_to_mplace(constant)?.into();
         // FIXME: Once the visitor infrastructure landed, change validation to
@@ -595,10 +532,10 @@ fn validate_and_turn_into_const<'a, 'tcx>(
                 op,
                 path,
                 Some(&mut ref_tracking),
-                /* const_mode */ true,
+                true, // const mode
             )?;
         }
-        // Now that we validated, turn this into a proper constant
+        // Now that we validated, turn this into a proper constant.
         let def_id = cid.instance.def.def_id();
         let normalize = tcx.is_static(def_id).is_none() && cid.promoted.is_none();
         op_to_const(&ecx, op, normalize)
diff --git a/src/librustc_mir/dataflow/at_location.rs b/src/librustc_mir/dataflow/at_location.rs
index 375bc4fead443..d43fa4257e06c 100644
--- a/src/librustc_mir/dataflow/at_location.rs
+++ b/src/librustc_mir/dataflow/at_location.rs
@@ -4,8 +4,8 @@
 use rustc::mir::{BasicBlock, Location};
 use rustc_data_structures::bit_set::{BitIter, BitSet, HybridBitSet};
 
-use dataflow::{BitDenotation, BlockSets, DataflowResults};
-use dataflow::move_paths::{HasMoveData, MovePathIndex};
+use crate::dataflow::{BitDenotation, BlockSets, DataflowResults};
+use crate::dataflow::move_paths::{HasMoveData, MovePathIndex};
 
 use std::iter;
 
@@ -26,14 +26,14 @@ pub trait FlowsAtLocation {
     /// effects don't apply to the unwind edge).
     fn reset_to_exit_of(&mut self, bb: BasicBlock);
 
-    /// Build gen + kill sets for statement at `loc`.
+    /// Builds gen and kill sets for statement at `loc`.
     ///
     /// Note that invoking this method alone does not change the
     /// `curr_state` -- you must invoke `apply_local_effect`
     /// afterwards.
     fn reconstruct_statement_effect(&mut self, loc: Location);
 
-    /// Build gen + kill sets for terminator for `loc`.
+    /// Builds gen and kill sets for terminator for `loc`.
     ///
     /// Note that invoking this method alone does not change the
     /// `curr_state` -- you must invoke `apply_local_effect`
@@ -115,7 +115,7 @@ where
     }
 
     /// Returns an iterator over the elements present in the current state.
-    pub fn iter_incoming(&self) -> iter::Peekable<BitIter<BD::Idx>> {
+    pub fn iter_incoming(&self) -> iter::Peekable<BitIter<'_, BD::Idx>> {
         self.curr_state.iter().peekable()
     }
 
@@ -124,7 +124,7 @@ where
     /// Invokes `f` with an iterator over the resulting state.
     pub fn with_iter_outgoing<F>(&self, f: F)
     where
-        F: FnOnce(BitIter<BD::Idx>),
+        F: FnOnce(BitIter<'_, BD::Idx>),
     {
         let mut curr_state = self.curr_state.clone();
         curr_state.union(&self.stmt_gen);
diff --git a/src/librustc_mir/dataflow/drop_flag_effects.rs b/src/librustc_mir/dataflow/drop_flag_effects.rs
index 22fb7a3bc470e..151a004dce942 100644
--- a/src/librustc_mir/dataflow/drop_flag_effects.rs
+++ b/src/librustc_mir/dataflow/drop_flag_effects.rs
@@ -1,6 +1,6 @@
 use rustc::mir::{self, Mir, Location};
 use rustc::ty::{self, TyCtxt};
-use util::elaborate_drops::DropFlagState;
+use crate::util::elaborate_drops::DropFlagState;
 
 use super::{MoveDataParamEnv};
 use super::indexes::MovePathIndex;
@@ -44,8 +44,8 @@ pub fn move_path_children_matching<'tcx, F>(move_data: &MoveData<'tcx>,
 /// In both cases, the contents can only be accessed if and only if
 /// their parents are initialized. This implies for example that there
 /// is no need to maintain separate drop flags to track such state.
-///
-/// FIXME: we have to do something for moving slice patterns.
+//
+// FIXME: we have to do something for moving slice patterns.
 fn place_contents_drop_state_cannot_differ<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                                             mir: &Mir<'tcx>,
                                                             place: &mir::Place<'tcx>) -> bool {
diff --git a/src/librustc_mir/dataflow/graphviz.rs b/src/librustc_mir/dataflow/graphviz.rs
index 34752baa020e2..c7f6983be6192 100644
--- a/src/librustc_mir/dataflow/graphviz.rs
+++ b/src/librustc_mir/dataflow/graphviz.rs
@@ -3,8 +3,6 @@
 use syntax::ast::NodeId;
 use rustc::mir::{BasicBlock, Mir};
 
-use dot;
-
 use std::fs;
 use std::io;
 use std::marker::PhantomData;
@@ -59,7 +57,7 @@ pub type Node = BasicBlock;
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub struct Edge { source: BasicBlock, index: usize }
 
-fn outgoing(mir: &Mir, bb: BasicBlock) -> Vec<Edge> {
+fn outgoing(mir: &Mir<'_>, bb: BasicBlock) -> Vec<Edge> {
     (0..mir[bb].terminator().successors().count())
         .map(|index| Edge { source: bb, index: index}).collect()
 }
@@ -70,18 +68,18 @@ impl<'a, 'tcx, MWF, P> dot::Labeller<'a> for Graph<'a, 'tcx, MWF, P>
 {
     type Node = Node;
     type Edge = Edge;
-    fn graph_id(&self) -> dot::Id {
+    fn graph_id(&self) -> dot::Id<'_> {
         dot::Id::new(format!("graph_for_node_{}",
                              self.mbcx.node_id()))
             .unwrap()
     }
 
-    fn node_id(&self, n: &Node) -> dot::Id {
+    fn node_id(&self, n: &Node) -> dot::Id<'_> {
         dot::Id::new(format!("bb_{}", n.index()))
             .unwrap()
     }
 
-    fn node_label(&self, n: &Node) -> dot::LabelText {
+    fn node_label(&self, n: &Node) -> dot::LabelText<'_> {
         // Node label is something like this:
         // +---------+----------------------------------+------------------+------------------+
         // | ENTRY   | MIR                              | GEN              | KILL             |
@@ -105,7 +103,7 @@ impl<'a, 'tcx, MWF, P> dot::Labeller<'a> for Graph<'a, 'tcx, MWF, P>
     }
 
 
-    fn node_shape(&self, _n: &Node) -> Option<dot::LabelText> {
+    fn node_shape(&self, _n: &Node) -> Option<dot::LabelText<'_>> {
         Some(dot::LabelText::label("none"))
     }
 
@@ -125,7 +123,7 @@ where MWF: MirWithFlowState<'tcx>,
                                          n: &Node,
                                          w: &mut W,
                                          block: BasicBlock,
-                                         mir: &Mir) -> io::Result<()> {
+                                         mir: &Mir<'_>) -> io::Result<()> {
         // Header rows
         const HDRS: [&str; 4] = ["ENTRY", "MIR", "BLOCK GENS", "BLOCK KILLS"];
         const HDR_FMT: &str = "bgcolor=\"grey\"";
@@ -145,12 +143,12 @@ where MWF: MirWithFlowState<'tcx>,
         Ok(())
     }
 
-    /// Build the verbose row: full MIR data, and detailed gen/kill/entry sets
+    /// Builds the verbose row: full MIR data, and detailed gen/kill/entry sets.
     fn node_label_verbose_row<W: io::Write>(&self,
                                             n: &Node,
                                             w: &mut W,
                                             block: BasicBlock,
-                                            mir: &Mir)
+                                            mir: &Mir<'_>)
                                             -> io::Result<()> {
         let i = n.index();
 
@@ -195,12 +193,12 @@ where MWF: MirWithFlowState<'tcx>,
         Ok(())
     }
 
-    /// Build the summary row: terminator, gen/kill/entry bit sets
+    /// Builds the summary row: terminator, gen/kill/entry bit sets.
     fn node_label_final_row<W: io::Write>(&self,
                                           n: &Node,
                                           w: &mut W,
                                           block: BasicBlock,
-                                          mir: &Mir)
+                                          mir: &Mir<'_>)
                                           -> io::Result<()> {
         let i = n.index();
 
@@ -241,7 +239,7 @@ impl<'a, 'tcx, MWF, P> dot::GraphWalk<'a> for Graph<'a, 'tcx, MWF, P>
 {
     type Node = Node;
     type Edge = Edge;
-    fn nodes(&self) -> dot::Nodes<Node> {
+    fn nodes(&self) -> dot::Nodes<'_, Node> {
         self.mbcx.mir()
             .basic_blocks()
             .indices()
@@ -249,7 +247,7 @@ impl<'a, 'tcx, MWF, P> dot::GraphWalk<'a> for Graph<'a, 'tcx, MWF, P>
             .into()
     }
 
-    fn edges(&self) -> dot::Edges<Edge> {
+    fn edges(&self) -> dot::Edges<'_, Edge> {
         let mir = self.mbcx.mir();
 
         mir.basic_blocks()
diff --git a/src/librustc_mir/dataflow/impls/borrowed_locals.rs b/src/librustc_mir/dataflow/impls/borrowed_locals.rs
index 9d03e35a35069..51d628ce6c5c2 100644
--- a/src/librustc_mir/dataflow/impls/borrowed_locals.rs
+++ b/src/librustc_mir/dataflow/impls/borrowed_locals.rs
@@ -2,7 +2,7 @@ pub use super::*;
 
 use rustc::mir::*;
 use rustc::mir::visit::Visitor;
-use dataflow::BitDenotation;
+use crate::dataflow::BitDenotation;
 
 /// This calculates if any part of a MIR local could have previously been borrowed.
 /// This means that once a local has been borrowed, its bit will be set
@@ -38,7 +38,7 @@ impl<'a, 'tcx> BitDenotation<'tcx> for HaveBeenBorrowedLocals<'a, 'tcx> {
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<Local>,
+                        sets: &mut BlockSets<'_, Local>,
                         loc: Location) {
         let stmt = &self.mir[loc.block].statements[loc.statement_index];
 
@@ -54,7 +54,7 @@ impl<'a, 'tcx> BitDenotation<'tcx> for HaveBeenBorrowedLocals<'a, 'tcx> {
     }
 
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<Local>,
+                         sets: &mut BlockSets<'_, Local>,
                          loc: Location) {
         BorrowedLocalsVisitor {
             sets,
diff --git a/src/librustc_mir/dataflow/impls/borrows.rs b/src/librustc_mir/dataflow/impls/borrows.rs
index 0ceff4aa04898..beb0b3187082b 100644
--- a/src/librustc_mir/dataflow/impls/borrows.rs
+++ b/src/librustc_mir/dataflow/impls/borrows.rs
@@ -1,5 +1,5 @@
-use borrow_check::borrow_set::{BorrowSet, BorrowData};
-use borrow_check::place_ext::PlaceExt;
+use crate::borrow_check::borrow_set::{BorrowSet, BorrowData};
+use crate::borrow_check::place_ext::PlaceExt;
 
 use rustc::mir::{self, Location, Place, Mir};
 use rustc::ty::TyCtxt;
@@ -9,11 +9,11 @@ use rustc_data_structures::bit_set::{BitSet, BitSetOperator};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
 
-use dataflow::{BitDenotation, BlockSets, InitialFlow};
-pub use dataflow::indexes::BorrowIndex;
-use borrow_check::nll::region_infer::RegionInferenceContext;
-use borrow_check::nll::ToRegionVid;
-use borrow_check::places_conflict;
+use crate::dataflow::{BitDenotation, BlockSets, InitialFlow};
+pub use crate::dataflow::indexes::BorrowIndex;
+use crate::borrow_check::nll::region_infer::RegionInferenceContext;
+use crate::borrow_check::nll::ToRegionVid;
+use crate::borrow_check::places_conflict;
 
 use std::rc::Rc;
 
@@ -163,7 +163,7 @@ impl<'a, 'gcx, 'tcx> Borrows<'a, 'gcx, 'tcx> {
     /// Add all borrows to the kill set, if those borrows are out of scope at `location`.
     /// That means they went out of a nonlexical scope
     fn kill_loans_out_of_scope_at_location(&self,
-                                           sets: &mut BlockSets<BorrowIndex>,
+                                           sets: &mut BlockSets<'_, BorrowIndex>,
                                            location: Location) {
         // NOTE: The state associated with a given `location`
         // reflects the dataflow on entry to the statement.
@@ -184,7 +184,7 @@ impl<'a, 'gcx, 'tcx> Borrows<'a, 'gcx, 'tcx> {
     /// Kill any borrows that conflict with `place`.
     fn kill_borrows_on_place(
         &self,
-        sets: &mut BlockSets<BorrowIndex>,
+        sets: &mut BlockSets<'_, BorrowIndex>,
         place: &Place<'tcx>
     ) {
         debug!("kill_borrows_on_place: place={:?}", place);
@@ -215,8 +215,8 @@ impl<'a, 'gcx, 'tcx> Borrows<'a, 'gcx, 'tcx> {
             if places_conflict::places_conflict(
                 self.tcx,
                 self.mir,
-                place,
                 &borrow_data.borrowed_place,
+                place,
                 places_conflict::PlaceConflictBias::NoOverlap,
             ) {
                 debug!(
@@ -243,13 +243,13 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for Borrows<'a, 'gcx, 'tcx> {
     }
 
     fn before_statement_effect(&self,
-                               sets: &mut BlockSets<BorrowIndex>,
+                               sets: &mut BlockSets<'_, BorrowIndex>,
                                location: Location) {
         debug!("Borrows::before_statement_effect sets: {:?} location: {:?}", sets, location);
         self.kill_loans_out_of_scope_at_location(sets, location);
     }
 
-    fn statement_effect(&self, sets: &mut BlockSets<BorrowIndex>, location: Location) {
+    fn statement_effect(&self, sets: &mut BlockSets<'_, BorrowIndex>, location: Location) {
         debug!("Borrows::statement_effect: sets={:?} location={:?}", sets, location);
 
         let block = &self.mir.basic_blocks().get(location.block).unwrap_or_else(|| {
@@ -307,13 +307,13 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for Borrows<'a, 'gcx, 'tcx> {
     }
 
     fn before_terminator_effect(&self,
-                                sets: &mut BlockSets<BorrowIndex>,
+                                sets: &mut BlockSets<'_, BorrowIndex>,
                                 location: Location) {
         debug!("Borrows::before_terminator_effect sets: {:?} location: {:?}", sets, location);
         self.kill_loans_out_of_scope_at_location(sets, location);
     }
 
-    fn terminator_effect(&self, _: &mut BlockSets<BorrowIndex>, _: Location) {}
+    fn terminator_effect(&self, _: &mut BlockSets<'_, BorrowIndex>, _: Location) {}
 
     fn propagate_call_return(
         &self,
diff --git a/src/librustc_mir/dataflow/impls/mod.rs b/src/librustc_mir/dataflow/impls/mod.rs
index 1ccda3a12e433..cc92ebfab89b7 100644
--- a/src/librustc_mir/dataflow/impls/mod.rs
+++ b/src/librustc_mir/dataflow/impls/mod.rs
@@ -9,7 +9,7 @@ use rustc_data_structures::indexed_vec::Idx;
 
 use super::MoveDataParamEnv;
 
-use util::elaborate_drops::DropFlagState;
+use crate::util::elaborate_drops::DropFlagState;
 
 use super::move_paths::{HasMoveData, MoveData, MovePathIndex, InitIndex};
 use super::move_paths::{LookupResult, InitKind};
@@ -143,13 +143,6 @@ impl<'a, 'gcx, 'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'a, 'gcx, 't
 /// initialized upon reaching a particular point in the control flow
 /// for a function.
 ///
-/// FIXME: Note that once flow-analysis is complete, this should be
-/// the set-complement of MaybeUninitializedPlaces; thus we can get rid
-/// of one or the other of these two. I'm inclined to get rid of
-/// MaybeUninitializedPlaces, simply because the sets will tend to be
-/// smaller in this analysis and thus easier for humans to process
-/// when debugging.
-///
 /// For example, in code like the following, we have corresponding
 /// dataflow information shown in the right-hand comments.
 ///
@@ -251,7 +244,7 @@ impl<'a, 'gcx, 'tcx> HasMoveData<'tcx> for EverInitializedPlaces<'a, 'gcx, 'tcx>
 
 
 impl<'a, 'gcx, 'tcx> MaybeInitializedPlaces<'a, 'gcx, 'tcx> {
-    fn update_bits(sets: &mut BlockSets<MovePathIndex>, path: MovePathIndex,
+    fn update_bits(sets: &mut BlockSets<'_, MovePathIndex>, path: MovePathIndex,
                    state: DropFlagState)
     {
         match state {
@@ -262,7 +255,7 @@ impl<'a, 'gcx, 'tcx> MaybeInitializedPlaces<'a, 'gcx, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> MaybeUninitializedPlaces<'a, 'gcx, 'tcx> {
-    fn update_bits(sets: &mut BlockSets<MovePathIndex>, path: MovePathIndex,
+    fn update_bits(sets: &mut BlockSets<'_, MovePathIndex>, path: MovePathIndex,
                    state: DropFlagState)
     {
         match state {
@@ -273,7 +266,7 @@ impl<'a, 'gcx, 'tcx> MaybeUninitializedPlaces<'a, 'gcx, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> DefinitelyInitializedPlaces<'a, 'gcx, 'tcx> {
-    fn update_bits(sets: &mut BlockSets<MovePathIndex>, path: MovePathIndex,
+    fn update_bits(sets: &mut BlockSets<'_, MovePathIndex>, path: MovePathIndex,
                    state: DropFlagState)
     {
         match state {
@@ -300,7 +293,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for MaybeInitializedPlaces<'a, 'gcx, 't
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<MovePathIndex>,
+                        sets: &mut BlockSets<'_, MovePathIndex>,
                         location: Location)
     {
         drop_flag_effects_for_location(
@@ -311,7 +304,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for MaybeInitializedPlaces<'a, 'gcx, 't
     }
 
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<MovePathIndex>,
+                         sets: &mut BlockSets<'_, MovePathIndex>,
                          location: Location)
     {
         drop_flag_effects_for_location(
@@ -358,7 +351,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for MaybeUninitializedPlaces<'a, 'gcx,
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<MovePathIndex>,
+                        sets: &mut BlockSets<'_, MovePathIndex>,
                         location: Location)
     {
         drop_flag_effects_for_location(
@@ -369,7 +362,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for MaybeUninitializedPlaces<'a, 'gcx,
     }
 
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<MovePathIndex>,
+                         sets: &mut BlockSets<'_, MovePathIndex>,
                          location: Location)
     {
         drop_flag_effects_for_location(
@@ -414,7 +407,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for DefinitelyInitializedPlaces<'a, 'gc
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<MovePathIndex>,
+                        sets: &mut BlockSets<'_, MovePathIndex>,
                         location: Location)
     {
         drop_flag_effects_for_location(
@@ -425,7 +418,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for DefinitelyInitializedPlaces<'a, 'gc
     }
 
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<MovePathIndex>,
+                         sets: &mut BlockSets<'_, MovePathIndex>,
                          location: Location)
     {
         drop_flag_effects_for_location(
@@ -464,7 +457,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for EverInitializedPlaces<'a, 'gcx, 'tc
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<InitIndex>,
+                        sets: &mut BlockSets<'_, InitIndex>,
                         location: Location) {
         let (_, mir, move_data) = (self.tcx, self.mir, self.move_data());
         let stmt = &mir[location.block].statements[location.statement_index];
@@ -511,7 +504,7 @@ impl<'a, 'gcx, 'tcx> BitDenotation<'tcx> for EverInitializedPlaces<'a, 'gcx, 'tc
     }
 
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<InitIndex>,
+                         sets: &mut BlockSets<'_, InitIndex>,
                          location: Location)
     {
         let (mir, move_data) = (self.mir, self.move_data());
diff --git a/src/librustc_mir/dataflow/impls/storage_liveness.rs b/src/librustc_mir/dataflow/impls/storage_liveness.rs
index 9c17076e6fde0..6b8eb6f17f6c1 100644
--- a/src/librustc_mir/dataflow/impls/storage_liveness.rs
+++ b/src/librustc_mir/dataflow/impls/storage_liveness.rs
@@ -1,7 +1,7 @@
 pub use super::*;
 
 use rustc::mir::*;
-use dataflow::BitDenotation;
+use crate::dataflow::BitDenotation;
 
 #[derive(Copy, Clone)]
 pub struct MaybeStorageLive<'a, 'tcx: 'a> {
@@ -31,7 +31,7 @@ impl<'a, 'tcx> BitDenotation<'tcx> for MaybeStorageLive<'a, 'tcx> {
     }
 
     fn statement_effect(&self,
-                        sets: &mut BlockSets<Local>,
+                        sets: &mut BlockSets<'_, Local>,
                         loc: Location) {
         let stmt = &self.mir[loc.block].statements[loc.statement_index];
 
@@ -43,7 +43,7 @@ impl<'a, 'tcx> BitDenotation<'tcx> for MaybeStorageLive<'a, 'tcx> {
     }
 
     fn terminator_effect(&self,
-                         _sets: &mut BlockSets<Local>,
+                         _sets: &mut BlockSets<'_, Local>,
                          _loc: Location) {
         // Terminators have no effect
     }
diff --git a/src/librustc_mir/dataflow/mod.rs b/src/librustc_mir/dataflow/mod.rs
index f09db970b7353..c24a776605cb8 100644
--- a/src/librustc_mir/dataflow/mod.rs
+++ b/src/librustc_mir/dataflow/mod.rs
@@ -58,7 +58,7 @@ impl DebugFormatted {
 }
 
 impl fmt::Debug for DebugFormatted {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(w, "{}", self.0)
     }
 }
@@ -525,7 +525,7 @@ impl<'a, E:Idx> BlockSets<'a, E> {
 
 impl<E:Idx> AllSets<E> {
     pub fn bits_per_block(&self) -> usize { self.bits_per_block }
-    pub fn for_block(&mut self, block_idx: usize) -> BlockSets<E> {
+    pub fn for_block(&mut self, block_idx: usize) -> BlockSets<'_, E> {
         BlockSets {
             on_entry: &mut self.on_entry_sets[block_idx],
             gen_set: &mut self.gen_sets[block_idx],
@@ -574,21 +574,21 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// the block's start, not necessarily the state immediately prior
     /// to the statement/terminator under analysis.
     ///
-    /// In either case, the passed reference is mutable; but this is a
+    /// In either case, the passed reference is mutable, but this is a
     /// wart from using the `BlockSets` type in the API; the intention
     /// is that the `statement_effect` and `terminator_effect` methods
     /// mutate only the gen/kill sets.
-    ///
-    /// FIXME: We should consider enforcing the intention described in
-    /// the previous paragraph by passing the three sets in separate
-    /// parameters to encode their distinct mutabilities.
+    //
+    // FIXME: we should consider enforcing the intention described in
+    // the previous paragraph by passing the three sets in separate
+    // parameters to encode their distinct mutabilities.
     fn accumulates_intrablock_state() -> bool { false }
 
     /// A name describing the dataflow analysis that this
-    /// BitDenotation is supporting.  The name should be something
-    /// suitable for plugging in as part of a filename e.g., avoid
+    /// `BitDenotation` is supporting. The name should be something
+    /// suitable for plugging in as part of a filename (i.e., avoid
     /// space-characters or other things that tend to look bad on a
-    /// file system, like slashes or periods. It is also better for
+    /// file system, like slashes or periods). It is also better for
     /// the name to be reasonably short, again because it will be
     /// plugged into a filename.
     fn name() -> &'static str;
@@ -616,7 +616,7 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// applied, in that order, before moving for the next
     /// statement.
     fn before_statement_effect(&self,
-                               _sets: &mut BlockSets<Self::Idx>,
+                               _sets: &mut BlockSets<'_, Self::Idx>,
                                _location: Location) {}
 
     /// Mutates the block-sets (the flow sets for the given
@@ -630,7 +630,7 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// `bb_data` is the sequence of statements identified by `bb` in
     /// the MIR.
     fn statement_effect(&self,
-                        sets: &mut BlockSets<Self::Idx>,
+                        sets: &mut BlockSets<'_, Self::Idx>,
                         location: Location);
 
     /// Similar to `terminator_effect`, except it applies
@@ -645,7 +645,7 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// applied, in that order, before moving for the next
     /// terminator.
     fn before_terminator_effect(&self,
-                                _sets: &mut BlockSets<Self::Idx>,
+                                _sets: &mut BlockSets<'_, Self::Idx>,
                                 _location: Location) {}
 
     /// Mutates the block-sets (the flow sets for the given
@@ -659,7 +659,7 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// The effects applied here cannot depend on which branch the
     /// terminator took.
     fn terminator_effect(&self,
-                         sets: &mut BlockSets<Self::Idx>,
+                         sets: &mut BlockSets<'_, Self::Idx>,
                          location: Location);
 
     /// Mutates the block-sets according to the (flow-dependent)
@@ -676,11 +676,11 @@ pub trait BitDenotation<'tcx>: BitSetOperator {
     /// flow-dependent, the current MIR cannot encode them via just
     /// GEN and KILL sets attached to the block, and so instead we add
     /// this extra machinery to represent the flow-dependent effect.
-    ///
-    /// FIXME: Right now this is a bit of a wart in the API. It might
-    /// be better to represent this as an additional gen- and
-    /// kill-sets associated with each edge coming out of the basic
-    /// block.
+    //
+    // FIXME: right now this is a bit of a wart in the API. It might
+    // be better to represent this as an additional gen- and
+    // kill-sets associated with each edge coming out of the basic
+    // block.
     fn propagate_call_return(
         &self,
         in_out: &mut BitSet<Self::Idx>,
diff --git a/src/librustc_mir/dataflow/move_paths/abs_domain.rs b/src/librustc_mir/dataflow/move_paths/abs_domain.rs
index ff594fd3bed8c..6dcc0325ec1ac 100644
--- a/src/librustc_mir/dataflow/move_paths/abs_domain.rs
+++ b/src/librustc_mir/dataflow/move_paths/abs_domain.rs
@@ -1,12 +1,12 @@
 //! The move-analysis portion of borrowck needs to work in an abstract
-//! domain of lifted Places.  Most of the Place variants fall into a
+//! domain of lifted `Place`s. Most of the `Place` variants fall into a
 //! one-to-one mapping between the concrete and abstract (e.g., a
-//! field-deref on a local-variable, `x.field`, has the same meaning
-//! in both domains). Indexed-Projections are the exception: `a[x]`
+//! field-deref on a local variable, `x.field`, has the same meaning
+//! in both domains). Indexed projections are the exception: `a[x]`
 //! needs to be treated as mapping to the same move path as `a[y]` as
-//! well as `a[13]`, et cetera.
+//! well as `a[13]`, etc.
 //!
-//! (In theory the analysis could be extended to work with sets of
+//! (In theory, the analysis could be extended to work with sets of
 //! paths, so that `a[0]` and `a[13]` could be kept distinct, while
 //! `a[x]` would still overlap them both. But that is not this
 //! representation does today.)
diff --git a/src/librustc_mir/dataflow/move_paths/mod.rs b/src/librustc_mir/dataflow/move_paths/mod.rs
index d77216220ac2b..efd979a7da4fb 100644
--- a/src/librustc_mir/dataflow/move_paths/mod.rs
+++ b/src/librustc_mir/dataflow/move_paths/mod.rs
@@ -37,7 +37,7 @@ pub(crate) mod indexes {
             }
 
             impl fmt::Debug for $Index {
-                fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+                fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
                     write!(fmt, "{}{}", $debug_name, self.index())
                 }
             }
@@ -62,7 +62,7 @@ pub use self::indexes::MoveOutIndex;
 pub use self::indexes::InitIndex;
 
 impl MoveOutIndex {
-    pub fn move_path_index(&self, move_data: &MoveData) -> MovePathIndex {
+    pub fn move_path_index(&self, move_data: &MoveData<'_>) -> MovePathIndex {
         move_data.moves[*self].path
     }
 }
@@ -88,7 +88,10 @@ pub struct MovePath<'tcx> {
 }
 
 impl<'tcx> MovePath<'tcx> {
-    pub fn parents(&self, move_paths: &IndexVec<MovePathIndex, MovePath>) -> Vec<MovePathIndex> {
+    pub fn parents(
+        &self,
+        move_paths: &IndexVec<MovePathIndex, MovePath<'_>>,
+    ) -> Vec<MovePathIndex> {
         let mut parents = Vec::new();
 
         let mut curr_parent = self.parent;
@@ -102,7 +105,7 @@ impl<'tcx> MovePath<'tcx> {
 }
 
 impl<'tcx> fmt::Debug for MovePath<'tcx> {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(w, "MovePath {{")?;
         if let Some(parent) = self.parent {
             write!(w, " parent: {:?},", parent)?;
@@ -118,7 +121,7 @@ impl<'tcx> fmt::Debug for MovePath<'tcx> {
 }
 
 impl<'tcx> fmt::Display for MovePath<'tcx> {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(w, "{:?}", self.place)
     }
 }
@@ -166,7 +169,7 @@ impl<T> IndexMut<Location> for LocationMap<T> {
 }
 
 impl<T> LocationMap<T> where T: Default + Clone {
-    fn new(mir: &Mir) -> Self {
+    fn new(mir: &Mir<'_>) -> Self {
         LocationMap {
             map: mir.basic_blocks().iter().map(|block| {
                 vec![T::default(); block.statements.len()+1]
@@ -190,7 +193,7 @@ pub struct MoveOut {
 }
 
 impl fmt::Debug for MoveOut {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(fmt, "{:?}@{:?}", self.path, self.source)
     }
 }
@@ -227,7 +230,7 @@ pub enum InitKind {
 }
 
 impl fmt::Debug for Init {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(fmt, "{:?}@{:?} ({:?})", self.path, self.location, self.kind)
     }
 }
diff --git a/src/librustc_mir/diagnostics.rs b/src/librustc_mir/diagnostics.rs
index ea9e19c75c215..f369324157a9e 100644
--- a/src/librustc_mir/diagnostics.rs
+++ b/src/librustc_mir/diagnostics.rs
@@ -690,7 +690,7 @@ fn main() {
 }
 ```
 
-See also https://doc.rust-lang.org/book/first-edition/unsafe.html
+See also https://doc.rust-lang.org/book/ch19-01-unsafe-rust.html
 "##,
 
 E0373: r##"
@@ -873,7 +873,7 @@ that at most one writer or multiple readers can access the data at any one time.
 If you wish to learn more about ownership in Rust, start with the chapter in the
 Book:
 
-https://doc.rust-lang.org/book/first-edition/ownership.html
+https://doc.rust-lang.org/book/ch04-00-understanding-ownership.html
 "##,
 
 E0383: r##"
@@ -1127,9 +1127,9 @@ A borrow of a constant containing interior mutability was attempted. Erroneous
 code example:
 
 ```compile_fail,E0492
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
+use std::sync::atomic::AtomicUsize;
 
-const A: AtomicUsize = ATOMIC_USIZE_INIT;
+const A: AtomicUsize = AtomicUsize::new(0);
 static B: &'static AtomicUsize = &A;
 // error: cannot borrow a constant which may contain interior mutability,
 //        create a static instead
@@ -1145,9 +1145,9 @@ explicitly a single memory location, which can be mutated at will.
 So, in order to solve this error, either use statics which are `Sync`:
 
 ```
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
+use std::sync::atomic::AtomicUsize;
 
-static A: AtomicUsize = ATOMIC_USIZE_INIT;
+static A: AtomicUsize = AtomicUsize::new(0);
 static B: &'static AtomicUsize = &A; // ok!
 ```
 
@@ -1207,7 +1207,7 @@ let mut a = &mut i;
 
 Please note that in rust, you can either have many immutable references, or one
 mutable reference. Take a look at
-https://doc.rust-lang.org/stable/book/references-and-borrowing.html for more
+https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html for more
 information. Example:
 
 
@@ -1374,7 +1374,7 @@ fn foo(a: &mut i32) {
 ```
 
 For more information on the rust ownership system, take a look at
-https://doc.rust-lang.org/stable/book/references-and-borrowing.html.
+https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html.
 "##,
 
 E0503: r##"
@@ -1430,7 +1430,7 @@ fn main() {
 ```
 
 You can find more information about borrowing in the rust-book:
-http://doc.rust-lang.org/stable/book/references-and-borrowing.html
+http://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html
 "##,
 
 E0504: r##"
@@ -1545,20 +1545,22 @@ Erroneous code example:
 ```compile_fail,E0505
 struct Value {}
 
+fn borrow(val: &Value) {}
+
 fn eat(val: Value) {}
 
 fn main() {
     let x = Value{};
-    {
-        let _ref_to_val: &Value = &x;
-        eat(x);
-    }
+    let _ref_to_val: &Value = &x;
+    eat(x);
+    borrow(_ref_to_val);
 }
 ```
 
-Here, the function `eat` takes the ownership of `x`. However,
-`x` cannot be moved because it was borrowed to `_ref_to_val`.
-To fix that you can do few different things:
+Here, the function `eat` takes ownership of `x`. However,
+`x` cannot be moved because the borrow to `_ref_to_val`
+needs to last till the function `borrow`.
+To fix that you can do a few different things:
 
 * Try to avoid moving the variable.
 * Release borrow before move.
@@ -1569,14 +1571,15 @@ Examples:
 ```
 struct Value {}
 
+fn borrow(val: &Value) {}
+
 fn eat(val: &Value) {}
 
 fn main() {
     let x = Value{};
-    {
-        let _ref_to_val: &Value = &x;
-        eat(&x); // pass by reference, if it's possible
-    }
+    let _ref_to_val: &Value = &x;
+    eat(&x); // pass by reference, if it's possible
+    borrow(_ref_to_val);
 }
 ```
 
@@ -1585,12 +1588,15 @@ Or:
 ```
 struct Value {}
 
+fn borrow(val: &Value) {}
+
 fn eat(val: Value) {}
 
 fn main() {
     let x = Value{};
     {
         let _ref_to_val: &Value = &x;
+        borrow(_ref_to_val);
     }
     eat(x); // release borrow and then move it.
 }
@@ -1602,19 +1608,20 @@ Or:
 #[derive(Clone, Copy)] // implement Copy trait
 struct Value {}
 
+fn borrow(val: &Value) {}
+
 fn eat(val: Value) {}
 
 fn main() {
     let x = Value{};
-    {
-        let _ref_to_val: &Value = &x;
-        eat(x); // it will be copied here.
-    }
+    let _ref_to_val: &Value = &x;
+    eat(x); // it will be copied here.
+    borrow(_ref_to_val);
 }
 ```
 
 You can find more information about borrowing in the rust-book:
-http://doc.rust-lang.org/stable/book/references-and-borrowing.html
+http://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html
 "##,
 
 E0506: r##"
@@ -1825,7 +1832,7 @@ mem::replace(&mut borrowed.knight, TheDarkKnight).nothing_is_true(); // ok!
 ```
 
 You can find more information about borrowing in the rust-book:
-http://doc.rust-lang.org/book/first-edition/references-and-borrowing.html
+http://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html
 "##,
 
 E0508: r##"
@@ -2119,14 +2126,15 @@ This error occurs because a borrow in a generator persists across a
 yield point.
 
 ```compile_fail,E0626
-# #![feature(generators, generator_trait)]
+# #![feature(generators, generator_trait, pin)]
 # use std::ops::Generator;
+# use std::pin::Pin;
 let mut b = || {
     let a = &String::new(); // <-- This borrow...
     yield (); // ...is still in scope here, when the yield occurs.
     println!("{}", a);
 };
-unsafe { b.resume() };
+Pin::new(&mut b).resume();
 ```
 
 At present, it is not permitted to have a yield that occurs while a
@@ -2137,14 +2145,15 @@ resolve the previous example by removing the borrow and just storing
 the integer by value:
 
 ```
-# #![feature(generators, generator_trait)]
+# #![feature(generators, generator_trait, pin)]
 # use std::ops::Generator;
+# use std::pin::Pin;
 let mut b = || {
     let a = 3;
     yield ();
     println!("{}", a);
 };
-unsafe { b.resume() };
+Pin::new(&mut b).resume();
 ```
 
 This is a very simple case, of course. In more complex cases, we may
@@ -2154,37 +2163,40 @@ in those cases, something like the `Rc` or `Arc` types may be useful.
 This error also frequently arises with iteration:
 
 ```compile_fail,E0626
-# #![feature(generators, generator_trait)]
+# #![feature(generators, generator_trait, pin)]
 # use std::ops::Generator;
+# use std::pin::Pin;
 let mut b = || {
   let v = vec![1,2,3];
   for &x in &v { // <-- borrow of `v` is still in scope...
     yield x; // ...when this yield occurs.
   }
 };
-unsafe { b.resume() };
+Pin::new(&mut b).resume();
 ```
 
 Such cases can sometimes be resolved by iterating "by value" (or using
 `into_iter()`) to avoid borrowing:
 
 ```
-# #![feature(generators, generator_trait)]
+# #![feature(generators, generator_trait, pin)]
 # use std::ops::Generator;
+# use std::pin::Pin;
 let mut b = || {
   let v = vec![1,2,3];
   for x in v { // <-- Take ownership of the values instead!
     yield x; // <-- Now yield is OK.
   }
 };
-unsafe { b.resume() };
+Pin::new(&mut b).resume();
 ```
 
 If taking ownership is not an option, using indices can work too:
 
 ```
-# #![feature(generators, generator_trait)]
+# #![feature(generators, generator_trait, pin)]
 # use std::ops::Generator;
+# use std::pin::Pin;
 let mut b = || {
   let v = vec![1,2,3];
   let len = v.len(); // (*)
@@ -2193,7 +2205,7 @@ let mut b = || {
     yield x; // <-- Now yield is OK.
   }
 };
-unsafe { b.resume() };
+Pin::new(&mut b).resume();
 
 // (*) -- Unfortunately, these temporaries are currently required.
 // See <https://github.com/rust-lang/rust/issues/43122>.
@@ -2365,6 +2377,37 @@ let value = (&foo(), &foo());
 ```
 "##,
 
+E0723: r##"
+An feature unstable in `const` contexts was used.
+
+Erroneous code example:
+
+```compile_fail,E0723
+trait T {}
+
+impl T for () {}
+
+const fn foo() -> impl T { // error: `impl Trait` in const fn is unstable
+    ()
+}
+```
+
+To enable this feature on a nightly version of rustc, add the `const_fn`
+feature flag:
+
+```
+#![feature(const_fn)]
+
+trait T {}
+
+impl T for () {}
+
+const fn foo() -> impl T {
+    ()
+}
+```
+"##,
+
 }
 
 register_diagnostics! {
diff --git a/src/librustc_mir/hair/constant.rs b/src/librustc_mir/hair/constant.rs
index 37d741d2606d5..21c471d49ee66 100644
--- a/src/librustc_mir/hair/constant.rs
+++ b/src/librustc_mir/hair/constant.rs
@@ -35,7 +35,15 @@ crate fn lit_to_const<'a, 'gcx, 'tcx>(
         LitKind::Str(ref s, _) => {
             let s = s.as_str();
             let id = tcx.allocate_bytes(s.as_bytes());
-            ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64, &tcx)
+            ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64)
+        },
+        LitKind::Err(ref s) => {
+            let s = s.as_str();
+            let id = tcx.allocate_bytes(s.as_bytes());
+            return Ok(ty::Const {
+                val: ConstValue::new_slice(Scalar::Ptr(id.into()), s.len() as u64),
+                ty: tcx.types.err,
+            });
         },
         LitKind::ByteStr(ref data) => {
             let id = tcx.allocate_bytes(data);
diff --git a/src/librustc_mir/hair/cx/block.rs b/src/librustc_mir/hair/cx/block.rs
index ea8b2826732b4..4a64ddb73fc2e 100644
--- a/src/librustc_mir/hair/cx/block.rs
+++ b/src/librustc_mir/hair/cx/block.rs
@@ -1,6 +1,6 @@
-use hair::*;
-use hair::cx::Cx;
-use hair::cx::to_ref::ToRef;
+use crate::hair::{self, *};
+use crate::hair::cx::Cx;
+use crate::hair::cx::to_ref::ToRef;
 use rustc::middle::region;
 use rustc::hir;
 use rustc::ty;
@@ -46,12 +46,12 @@ fn mirror_stmts<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                                 -> Vec<StmtRef<'tcx>> {
     let mut result = vec![];
     for (index, stmt) in stmts.iter().enumerate() {
-        let hir_id = cx.tcx.hir().node_to_hir_id(stmt.node.id());
+        let hir_id = stmt.hir_id;
         let opt_dxn_ext = cx.region_scope_tree.opt_destruction_scope(hir_id.local_id);
-        let stmt_span = StatementSpan(cx.tcx.hir().span(stmt.node.id()));
+        let stmt_span = StatementSpan(cx.tcx.hir().span_by_hir_id(hir_id));
         match stmt.node {
-            hir::StmtKind::Expr(ref expr, _) |
-            hir::StmtKind::Semi(ref expr, _) => {
+            hir::StmtKind::Expr(ref expr) |
+            hir::StmtKind::Semi(ref expr) => {
                 result.push(StmtRef::Mirror(Box::new(Stmt {
                     kind: StmtKind::Expr {
                         scope: region::Scope {
@@ -64,52 +64,50 @@ fn mirror_stmts<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                     span: stmt_span,
                 })))
             }
-            hir::StmtKind::Decl(ref decl, _) => {
-                match decl.node {
-                    hir::DeclKind::Item(..) => {
-                        // ignore for purposes of the MIR
-                    }
-                    hir::DeclKind::Local(ref local) => {
-                        let remainder_scope = region::Scope {
-                            id: block_id,
-                            data: region::ScopeData::Remainder(
-                                region::FirstStatementIndex::new(index)),
-                        };
-
-                        let mut pattern = cx.pattern_from_hir(&local.pat);
+            hir::StmtKind::Item(..) => {
+                // ignore for purposes of the MIR
+            }
+            hir::StmtKind::Local(ref local) => {
+                let remainder_scope = region::Scope {
+                    id: block_id,
+                    data: region::ScopeData::Remainder(
+                        region::FirstStatementIndex::new(index)),
+                };
 
-                        if let Some(ty) = &local.ty {
-                            if let Some(&user_ty) = cx.tables.user_provided_types().get(ty.hir_id) {
-                                debug!("mirror_stmts: user_ty={:?}", user_ty);
-                                pattern = Pattern {
-                                    ty: pattern.ty,
-                                    span: pattern.span,
-                                    kind: Box::new(PatternKind::AscribeUserType {
-                                        user_ty: PatternTypeProjection::from_user_type(user_ty),
-                                        user_ty_span: ty.span,
-                                        subpattern: pattern,
-                                        variance: ty::Variance::Covariant,
-                                    })
-                                };
-                            }
-                        }
+                let mut pattern = cx.pattern_from_hir(&local.pat);
 
-                        result.push(StmtRef::Mirror(Box::new(Stmt {
-                            kind: StmtKind::Let {
-                                remainder_scope: remainder_scope,
-                                init_scope: region::Scope {
-                                    id: hir_id.local_id,
-                                    data: region::ScopeData::Node
+                if let Some(ty) = &local.ty {
+                    if let Some(&user_ty) = cx.tables.user_provided_types().get(ty.hir_id) {
+                        debug!("mirror_stmts: user_ty={:?}", user_ty);
+                        pattern = Pattern {
+                            ty: pattern.ty,
+                            span: pattern.span,
+                            kind: Box::new(PatternKind::AscribeUserType {
+                                ascription: hair::pattern::Ascription {
+                                    user_ty: PatternTypeProjection::from_user_type(user_ty),
+                                    user_ty_span: ty.span,
+                                    variance: ty::Variance::Covariant,
                                 },
-                                pattern,
-                                initializer: local.init.to_ref(),
-                                lint_level: cx.lint_level_of(local.id),
-                            },
-                            opt_destruction_scope: opt_dxn_ext,
-                            span: stmt_span,
-                        })));
+                                subpattern: pattern,
+                            })
+                        };
                     }
                 }
+
+                result.push(StmtRef::Mirror(Box::new(Stmt {
+                    kind: StmtKind::Let {
+                        remainder_scope: remainder_scope,
+                        init_scope: region::Scope {
+                            id: hir_id.local_id,
+                            data: region::ScopeData::Node
+                        },
+                        pattern,
+                        initializer: local.init.to_ref(),
+                        lint_level: cx.lint_level_of(local.id),
+                    },
+                    opt_destruction_scope: opt_dxn_ext,
+                    span: stmt_span,
+                })));
             }
         }
     }
@@ -119,7 +117,7 @@ fn mirror_stmts<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
 pub fn to_expr_ref<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                                    block: &'tcx hir::Block)
                                    -> ExprRef<'tcx> {
-    let block_ty = cx.tables().node_id_to_type(block.hir_id);
+    let block_ty = cx.tables().node_type(block.hir_id);
     let temp_lifetime = cx.region_scope_tree.temporary_scope(block.hir_id.local_id);
     let expr = Expr {
         ty: block_ty,
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index eb536fbcf69bb..10d04a80d7341 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -1,9 +1,9 @@
-use hair::*;
+use crate::hair::*;
+use crate::hair::cx::Cx;
+use crate::hair::cx::block;
+use crate::hair::cx::to_ref::ToRef;
+use crate::hair::util::UserAnnotatedTyHelpers;
 use rustc_data_structures::indexed_vec::Idx;
-use hair::cx::Cx;
-use hair::cx::block;
-use hair::cx::to_ref::ToRef;
-use hair::util::UserAnnotatedTyHelpers;
 use rustc::hir::def::{Def, CtorKind};
 use rustc::mir::interpret::{GlobalId, ErrorHandled};
 use rustc::ty::{self, AdtKind, Ty};
@@ -278,7 +278,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                     let user_ty = user_provided_types.get(fun.hir_id)
                         .map(|u_ty| *u_ty)
                         .map(|mut u_ty| {
-                            if let UserTypeAnnotation::TypeOf(ref mut did, _) = &mut u_ty.value {
+                            if let UserType::TypeOf(ref mut did, _) = &mut u_ty.value {
                                 *did = adt_def.did;
                             }
                             u_ty
@@ -304,7 +304,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                     }
                 } else {
                     ExprKind::Call {
-                        ty: cx.tables().node_id_to_type(fun.hir_id),
+                        ty: cx.tables().node_type(fun.hir_id),
                         fun: fun.to_ref(),
                         args: args.to_ref(),
                         from_hir_call: true,
@@ -342,7 +342,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
         }
 
         hir::ExprKind::Lit(ref lit) => ExprKind::Literal {
-            literal: cx.tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: cx.tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                 cx.const_eval_literal(&lit.node, expr_ty, lit.span, false)
             )),
             user_ty: None,
@@ -442,7 +442,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             } else {
                 if let hir::ExprKind::Lit(ref lit) = arg.node {
                     ExprKind::Literal {
-                        literal: cx.tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+                        literal: cx.tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                             cx.const_eval_literal(&lit.node, expr_ty, lit.span, true)
                         )),
                         user_ty: None,
@@ -677,7 +677,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                     let def = cx.tables().qpath_def(qpath, source.hir_id);
                     cx
                         .tables()
-                        .node_id_to_type(source.hir_id)
+                        .node_type(source.hir_id)
                         .ty_adt_def()
                         .and_then(|adt_def| {
                         match def {
@@ -702,7 +702,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                         ty: var_ty,
                         span: expr.span,
                         kind: ExprKind::Literal {
-                            literal: cx.tcx.intern_lazy_const(literal),
+                            literal: cx.tcx.mk_lazy_const(literal),
                             user_ty: None
                         },
                     }.to_ref();
@@ -797,7 +797,7 @@ fn user_substs_applied_to_def(
     cx: &mut Cx<'a, 'gcx, 'tcx>,
     hir_id: hir::HirId,
     def: &Def,
-) -> Option<ty::CanonicalUserTypeAnnotation<'tcx>> {
+) -> Option<ty::CanonicalUserType<'tcx>> {
     debug!("user_substs_applied_to_def: def={:?}", def);
     let user_provided_type = match def {
         // A reference to something callable -- e.g., a fn, method, or
@@ -856,7 +856,7 @@ fn method_callee<'a, 'gcx, 'tcx>(
         ty,
         span,
         kind: ExprKind::Literal {
-            literal: cx.tcx().intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: cx.tcx().mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::zero_sized(ty)
             )),
             user_ty,
@@ -918,8 +918,8 @@ fn convert_path_expr<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             let user_ty = user_substs_applied_to_def(cx, expr.hir_id, &def);
             debug!("convert_path_expr: user_ty={:?}", user_ty);
             ExprKind::Literal {
-                literal: cx.tcx.intern_lazy_const(ty::LazyConst::Evaluated(ty::Const::zero_sized(
-                    cx.tables().node_id_to_type(expr.hir_id),
+                literal: cx.tcx.mk_lazy_const(ty::LazyConst::Evaluated(ty::Const::zero_sized(
+                    cx.tables().node_type(expr.hir_id),
                 ))),
                 user_ty,
             }
@@ -930,7 +930,7 @@ fn convert_path_expr<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             let user_ty = user_substs_applied_to_def(cx, expr.hir_id, &def);
             debug!("convert_path_expr: (const) user_ty={:?}", user_ty);
             ExprKind::Literal {
-                literal: cx.tcx.intern_lazy_const(ty::LazyConst::Unevaluated(def_id, substs)),
+                literal: cx.tcx.mk_lazy_const(ty::LazyConst::Unevaluated(def_id, substs)),
                 user_ty,
             }
         },
@@ -940,7 +940,7 @@ fn convert_path_expr<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
             let user_provided_types = cx.tables.user_provided_types();
             let user_provided_type = user_provided_types.get(expr.hir_id).map(|u_ty| *u_ty);
             debug!("convert_path_expr: user_provided_type={:?}", user_provided_type);
-            match cx.tables().node_id_to_type(expr.hir_id).sty {
+            match cx.tables().node_type(expr.hir_id).sty {
                 // A unit struct/variant which is used as a value.
                 // We return a completely different ExprKind here to account for this special case.
                 ty::Adt(adt_def, substs) => {
@@ -980,11 +980,11 @@ fn convert_var<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
                    index,
                    closure_expr_id);
             let var_hir_id = cx.tcx.hir().node_to_hir_id(var_id);
-            let var_ty = cx.tables().node_id_to_type(var_hir_id);
+            let var_ty = cx.tables().node_type(var_hir_id);
 
             // FIXME free regions in closures are not right
             let closure_ty = cx.tables()
-                               .node_id_to_type(cx.tcx.hir().node_to_hir_id(closure_expr_id));
+                               .node_type(cx.tcx.hir().node_to_hir_id(closure_expr_id));
 
             // FIXME we're just hard-coding the idea that the
             // signature will be &self or &mut self and hence will
@@ -1188,7 +1188,7 @@ fn capture_freevar<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
     };
     let upvar_capture = cx.tables().upvar_capture(upvar_id);
     let temp_lifetime = cx.region_scope_tree.temporary_scope(closure_expr.hir_id.local_id);
-    let var_ty = cx.tables().node_id_to_type(var_hir_id);
+    let var_ty = cx.tables().node_type(var_hir_id);
     let captured_var = Expr {
         temp_lifetime,
         ty: var_ty,
diff --git a/src/librustc_mir/hair/cx/mod.rs b/src/librustc_mir/hair/cx/mod.rs
index 6113d88e09591..cd937d702fd77 100644
--- a/src/librustc_mir/hair/cx/mod.rs
+++ b/src/librustc_mir/hair/cx/mod.rs
@@ -1,11 +1,9 @@
-//! This module contains the code to convert from the wacky tcx data
-//! structures into the hair. The `builder` is generally ignorant of
-//! the tcx etc, and instead goes through the `Cx` for most of its
-//! work.
-//!
+//! This module contains the fcuntaiontliy to convert from the wacky tcx data
+//! structures into the HAIR. The `builder` is generally ignorant of the tcx,
+//! etc., and instead goes through the `Cx` for most of its work.
 
-use hair::*;
-use hair::util::UserAnnotatedTyHelpers;
+use crate::hair::*;
+use crate::hair::util::UserAnnotatedTyHelpers;
 
 use rustc_data_structures::indexed_vec::Idx;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
@@ -21,7 +19,7 @@ use syntax::attr;
 use syntax::symbol::Symbol;
 use rustc::hir;
 use rustc_data_structures::sync::Lrc;
-use hair::constant::{lit_to_const, LitToConstError};
+use crate::hair::constant::{lit_to_const, LitToConstError};
 
 #[derive(Clone)]
 pub struct Cx<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
@@ -44,10 +42,10 @@ pub struct Cx<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     /// What kind of body is being compiled.
     pub body_owner_kind: hir::BodyOwnerKind,
 
-    /// True if this constant/function needs overflow checks.
+    /// Whether this constant/function needs overflow checks.
     check_overflow: bool,
 
-    /// See field with the same name on `Mir`
+    /// See field with the same name on `Mir`.
     control_flow_destroyed: Vec<(Span, String)>,
 }
 
@@ -61,6 +59,7 @@ impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
         let constness = match body_owner_kind {
             hir::BodyOwnerKind::Const |
             hir::BodyOwnerKind::Static(_) => hir::Constness::Const,
+            hir::BodyOwnerKind::Closure |
             hir::BodyOwnerKind::Fn => hir::Constness::NotConst,
         };
 
@@ -99,7 +98,7 @@ impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
-    /// Normalizes `ast` into the appropriate `mirror` type.
+    /// Normalizes `ast` into the appropriate "mirror" type.
     pub fn mirror<M: Mirror<'tcx>>(&mut self, ast: M) -> M::Output {
         ast.make_mirror(self)
     }
@@ -109,7 +108,7 @@ impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
     }
 
     pub fn usize_literal(&mut self, value: u64) -> &'tcx ty::LazyConst<'tcx> {
-        self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_usize(self.tcx, value)))
+        self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_usize(self.tcx, value)))
     }
 
     pub fn bool_ty(&mut self) -> Ty<'tcx> {
@@ -121,11 +120,11 @@ impl<'a, 'gcx, 'tcx> Cx<'a, 'gcx, 'tcx> {
     }
 
     pub fn true_literal(&mut self) -> &'tcx ty::LazyConst<'tcx> {
-        self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bool(self.tcx, true)))
+        self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bool(self.tcx, true)))
     }
 
     pub fn false_literal(&mut self) -> &'tcx ty::LazyConst<'tcx> {
-        self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bool(self.tcx, false)))
+        self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bool(self.tcx, false)))
     }
 
     pub fn const_eval_literal(
@@ -238,7 +237,7 @@ impl UserAnnotatedTyHelpers<'gcx, 'tcx> for Cx<'_, 'gcx, 'tcx> {
     }
 }
 
-fn lint_level_for_hir_id(tcx: TyCtxt, mut id: ast::NodeId) -> ast::NodeId {
+fn lint_level_for_hir_id(tcx: TyCtxt<'_, '_, '_>, mut id: ast::NodeId) -> ast::NodeId {
     // Right now we insert a `with_ignore` node in the dep graph here to
     // ignore the fact that `lint_levels` below depends on the entire crate.
     // For now this'll prevent false positives of recompiling too much when
diff --git a/src/librustc_mir/hair/cx/to_ref.rs b/src/librustc_mir/hair/cx/to_ref.rs
index 1b87e4450c56e..a462c61c2acba 100644
--- a/src/librustc_mir/hair/cx/to_ref.rs
+++ b/src/librustc_mir/hair/cx/to_ref.rs
@@ -1,4 +1,4 @@
-use hair::*;
+use crate::hair::*;
 
 use rustc::hir;
 use syntax::ptr::P;
diff --git a/src/librustc_mir/hair/mod.rs b/src/librustc_mir/hair/mod.rs
index e902423cd30fc..e615b009cf370 100644
--- a/src/librustc_mir/hair/mod.rs
+++ b/src/librustc_mir/hair/mod.rs
@@ -9,7 +9,7 @@ use rustc::hir::def_id::DefId;
 use rustc::infer::canonical::Canonical;
 use rustc::middle::region;
 use rustc::ty::subst::Substs;
-use rustc::ty::{AdtDef, UpvarSubsts, Ty, Const, LazyConst, UserTypeAnnotation};
+use rustc::ty::{AdtDef, UpvarSubsts, Ty, Const, LazyConst, UserType};
 use rustc::ty::layout::VariantIdx;
 use rustc::hir;
 use syntax::ast;
@@ -265,7 +265,7 @@ pub enum ExprKind<'tcx> {
 
         /// Optional user-given substs: for something like `let x =
         /// Bar::<T> { ... }`.
-        user_ty: Option<Canonical<'tcx, UserTypeAnnotation<'tcx>>>,
+        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
 
         fields: Vec<FieldExprRef<'tcx>>,
         base: Option<FruInfo<'tcx>>
@@ -273,12 +273,12 @@ pub enum ExprKind<'tcx> {
     PlaceTypeAscription {
         source: ExprRef<'tcx>,
         /// Type that the user gave to this expression
-        user_ty: Option<Canonical<'tcx, UserTypeAnnotation<'tcx>>>,
+        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
     },
     ValueTypeAscription {
         source: ExprRef<'tcx>,
         /// Type that the user gave to this expression
-        user_ty: Option<Canonical<'tcx, UserTypeAnnotation<'tcx>>>,
+        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
     },
     Closure {
         closure_id: DefId,
@@ -288,7 +288,7 @@ pub enum ExprKind<'tcx> {
     },
     Literal {
         literal: &'tcx LazyConst<'tcx>,
-        user_ty: Option<Canonical<'tcx, UserTypeAnnotation<'tcx>>>,
+        user_ty: Option<Canonical<'tcx, UserType<'tcx>>>,
     },
     InlineAsm {
         asm: &'tcx hir::InlineAsm,
@@ -358,7 +358,7 @@ impl<'tcx> ExprRef<'tcx> {
 /// Mirroring is gradual: when you mirror an outer expression like `e1
 /// + e2`, the references to the inner expressions `e1` and `e2` are
 /// `ExprRef<'tcx>` instances, and they may or may not be eagerly
-/// mirrored.  This allows a single AST node from the compiler to
+/// mirrored. This allows a single AST node from the compiler to
 /// expand into one or more Hair nodes, which lets the Hair nodes be
 /// simpler.
 pub trait Mirror<'tcx> {
diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs
index 188a112044298..6910fb7e988bb 100644
--- a/src/librustc_mir/hair/pattern/_match.rs
+++ b/src/librustc_mir/hair/pattern/_match.rs
@@ -6,8 +6,8 @@
 ///
 /// The algorithm implemented here is a modified version of the one described in:
 /// http://moscova.inria.fr/~maranget/papers/warn/index.html
-/// However, to save future implementors from reading the original paper, I'm going
-/// to summarise the algorithm here to hopefully save time and be a little clearer
+/// However, to save future implementors from reading the original paper, we
+/// summarise the algorithm here to hopefully save time and be a little clearer
 /// (without being so rigorous).
 ///
 /// The core of the algorithm revolves about a "usefulness" check. In particular, we
@@ -221,13 +221,16 @@ impl<'a, 'tcx> LiteralExpander<'a, 'tcx> {
             // unsize array to slice if pattern is array but match value or other patterns are slice
             (ConstValue::Scalar(Scalar::Ptr(p)), ty::Array(t, n), ty::Slice(u)) => {
                 assert_eq!(t, u);
-                ConstValue::ScalarPair(
+                ConstValue::Slice(
                     Scalar::Ptr(p),
-                    n.map_evaluated(|val| val.val.try_to_scalar()).unwrap(),
+                    n.map_evaluated(|val| val.val.try_to_scalar())
+                        .unwrap()
+                        .to_usize(&self.tcx)
+                        .unwrap(),
                 )
             },
             // fat pointers stay the same
-            (ConstValue::ScalarPair(..), _, _) => val,
+            (ConstValue::Slice(..), _, _) => val,
             // FIXME(oli-obk): this is reachable for `const FOO: &&&u32 = &&&42;` being used
             _ => bug!("cannot deref {:#?}, {} -> {}", val, crty, rty),
         }
@@ -304,7 +307,7 @@ impl<'p, 'tcx> Matrix<'p, 'tcx> {
 /// + _     + [_, _, ..tail] +
 /// ++++++++++++++++++++++++++
 impl<'p, 'tcx> fmt::Debug for Matrix<'p, 'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "\n")?;
 
         let &Matrix(ref m) = self;
@@ -348,7 +351,7 @@ pub struct MatchCheckCtxt<'a, 'tcx: 'a> {
     /// The module in which the match occurs. This is necessary for
     /// checking inhabited-ness of types because whether a type is (visibly)
     /// inhabited can depend on whether it was defined in the current module or
-    /// not. eg. `struct Foo { _private: ! }` cannot be seen to be empty
+    /// not. E.g., `struct Foo { _private: ! }` cannot be seen to be empty
     /// outside it's module and should not be matchable with an empty match
     /// statement.
     pub module: DefId,
@@ -427,13 +430,24 @@ pub enum Constructor<'tcx> {
 }
 
 impl<'tcx> Constructor<'tcx> {
-    fn variant_index_for_adt(&self, adt: &'tcx ty::AdtDef) -> VariantIdx {
+    fn variant_index_for_adt<'a>(
+        &self,
+        cx: &MatchCheckCtxt<'a, 'tcx>,
+        adt: &'tcx ty::AdtDef,
+    ) -> VariantIdx {
         match self {
             &Variant(vid) => adt.variant_index_with_id(vid),
             &Single => {
                 assert!(!adt.is_enum());
                 VariantIdx::new(0)
             }
+            &ConstantValue(c) => {
+                crate::const_eval::const_variant_index(
+                    cx.tcx,
+                    cx.param_env,
+                    c,
+                ).unwrap()
+            },
             _ => bug!("bad constructor {:?} for adt {:?}", self, adt)
         }
     }
@@ -567,7 +581,7 @@ impl<'tcx> Witness<'tcx> {
                             PatternKind::Variant {
                                 adt_def: adt,
                                 substs,
-                                variant_index: ctor.variant_index_for_adt(adt),
+                                variant_index: ctor.variant_index_for_adt(cx, adt),
                                 subpatterns: pats
                             }
                         } else {
@@ -620,8 +634,8 @@ impl<'tcx> Witness<'tcx> {
 /// but is instead bounded by the maximum fixed length of slice patterns in
 /// the column of patterns being analyzed.
 ///
-/// We make sure to omit constructors that are statically impossible. eg for
-/// Option<!> we do not include Some(_) in the returned list of constructors.
+/// We make sure to omit constructors that are statically impossible. E.g., for
+/// `Option<!>`, we do not include `Some(_)` in the returned list of constructors.
 fn all_constructors<'a, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
                                   pcx: PatternContext<'tcx>)
                                   -> Vec<Constructor<'tcx>>
@@ -777,9 +791,9 @@ fn max_slice_length<'p, 'a: 'p, 'tcx: 'a, I>(
                         max_fixed_len,
                         n.unwrap_usize(cx.tcx),
                     ),
-                    (ConstValue::ScalarPair(_, n), ty::Slice(_)) => max_fixed_len = cmp::max(
+                    (ConstValue::Slice(_, n), ty::Slice(_)) => max_fixed_len = cmp::max(
                         max_fixed_len,
-                        n.to_usize(&cx.tcx).unwrap(),
+                        n,
                     ),
                     _ => {},
                 }
@@ -857,18 +871,24 @@ impl<'tcx> IntRange<'tcx> {
     }
 
     fn from_pat(tcx: TyCtxt<'_, 'tcx, 'tcx>,
-                pat: &Pattern<'tcx>)
+                mut pat: &Pattern<'tcx>)
                 -> Option<IntRange<'tcx>> {
-        Self::from_ctor(tcx, &match pat.kind {
-            box PatternKind::Constant { value } => ConstantValue(value),
-            box PatternKind::Range(PatternRange { lo, hi, ty, end }) => ConstantRange(
-                lo.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
-                hi.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
-                ty,
-                end,
-            ),
-            _ => return None,
-        })
+        let range = loop {
+            match pat.kind {
+                box PatternKind::Constant { value } => break ConstantValue(value),
+                box PatternKind::Range(PatternRange { lo, hi, ty, end }) => break ConstantRange(
+                    lo.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
+                    hi.to_bits(tcx, ty::ParamEnv::empty().and(ty)).unwrap(),
+                    ty,
+                    end,
+                ),
+                box PatternKind::AscribeUserType { ref subpattern, .. } => {
+                    pat = subpattern;
+                },
+                _ => return None,
+            }
+        };
+        Self::from_ctor(tcx, &range)
     }
 
     // The return value of `signed_bias` should be XORed with an endpoint to encode/decode it.
@@ -882,7 +902,7 @@ impl<'tcx> IntRange<'tcx> {
         }
     }
 
-    /// Convert a `RangeInclusive` to a `ConstantValue` or inclusive `ConstantRange`.
+    /// Converts a `RangeInclusive` to a `ConstantValue` or inclusive `ConstantRange`.
     fn range_to_ctor(
         tcx: TyCtxt<'_, 'tcx, 'tcx>,
         ty: Ty<'tcx>,
@@ -898,7 +918,7 @@ impl<'tcx> IntRange<'tcx> {
         }
     }
 
-    /// Return a collection of ranges that spans the values covered by `ranges`, subtracted
+    /// Returns a collection of ranges that spans the values covered by `ranges`, subtracted
     /// by the values covered by `self`: i.e., `ranges \ self` (in set notation).
     fn subtract_from(self,
                      tcx: TyCtxt<'_, 'tcx, 'tcx>,
@@ -1019,13 +1039,13 @@ fn compute_missing_ctors<'a, 'tcx: 'a>(
     }
 }
 
-/// Algorithm from http://moscova.inria.fr/~maranget/papers/warn/index.html
+/// Algorithm from http://moscova.inria.fr/~maranget/papers/warn/index.html.
 /// The algorithm from the paper has been modified to correctly handle empty
 /// types. The changes are:
 ///   (0) We don't exit early if the pattern matrix has zero rows. We just
 ///       continue to recurse over columns.
 ///   (1) all_constructors will only return constructors that are statically
-///       possible. eg. it will only return Ok for Result<T, !>
+///       possible. E.g., it will only return `Ok` for `Result<T, !>`.
 ///
 /// This finds whether a (row) vector `v` of patterns is 'useful' in relation
 /// to a set of such vectors `m` - this is defined as there being a set of
@@ -1033,8 +1053,8 @@ fn compute_missing_ctors<'a, 'tcx: 'a>(
 ///
 /// All the patterns at each column of the `matrix ++ v` matrix must
 /// have the same type, except that wildcard (PatternKind::Wild) patterns
-/// with type TyErr are also allowed, even if the "type of the column"
-/// is not TyErr. That is used to represent private fields, as using their
+/// with type `TyErr` are also allowed, even if the "type of the column"
+/// is not `TyErr`. That is used to represent private fields, as using their
 /// real type would assert that they are inhabited.
 ///
 /// This is used both for reachability checking (if a pattern isn't useful in
@@ -1101,7 +1121,7 @@ pub fn is_useful<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
     } else {
         debug!("is_useful - expanding wildcard");
 
-        let used_ctors: Vec<Constructor> = rows.iter().flat_map(|row| {
+        let used_ctors: Vec<Constructor<'_>> = rows.iter().flat_map(|row| {
             pat_constructors(cx, row[0], pcx).unwrap_or(vec![])
         }).collect();
         debug!("used_ctors = {:#?}", used_ctors);
@@ -1285,10 +1305,10 @@ fn is_useful_specialized<'p, 'a: 'p, 'tcx: 'a>(
 /// Slice patterns, however, can match slices of different lengths. For instance,
 /// `[a, b, ..tail]` can match a slice of length 2, 3, 4 and so on.
 ///
-/// Returns None in case of a catch-all, which can't be specialized.
+/// Returns `None` in case of a catch-all, which can't be specialized.
 fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt<'_, 'tcx>,
                           pat: &Pattern<'tcx>,
-                          pcx: PatternContext)
+                          pcx: PatternContext<'_>)
                           -> Option<Vec<Constructor<'tcx>>>
 {
     match *pat.kind {
@@ -1327,9 +1347,9 @@ fn pat_constructors<'tcx>(cx: &mut MatchCheckCtxt<'_, 'tcx>,
 /// This computes the arity of a constructor. The arity of a constructor
 /// is how many subpattern patterns of that constructor should be expanded to.
 ///
-/// For instance, a tuple pattern (_, 42, Some([])) has the arity of 3.
+/// For instance, a tuple pattern `(_, 42, Some([]))` has the arity of 3.
 /// A struct pattern's arity is the number of fields it contains, etc.
-fn constructor_arity(_cx: &MatchCheckCtxt, ctor: &Constructor, ty: Ty) -> u64 {
+fn constructor_arity(cx: &MatchCheckCtxt<'a, 'tcx>, ctor: &Constructor<'tcx>, ty: Ty<'tcx>) -> u64 {
     debug!("constructor_arity({:#?}, {:?})", ctor, ty);
     match ty.sty {
         ty::Tuple(ref fs) => fs.len() as u64,
@@ -1337,10 +1357,10 @@ fn constructor_arity(_cx: &MatchCheckCtxt, ctor: &Constructor, ty: Ty) -> u64 {
             Slice(length) => length,
             ConstantValue(_) => 0,
             _ => bug!("bad slice pattern {:?} {:?}", ctor, ty)
-        },
+        }
         ty::Ref(..) => 1,
         ty::Adt(adt, _) => {
-            adt.variants[ctor.variant_index_for_adt(adt)].fields.len() as u64
+            adt.variants[ctor.variant_index_for_adt(cx, adt)].fields.len() as u64
         }
         _ => 0
     }
@@ -1351,7 +1371,7 @@ fn constructor_arity(_cx: &MatchCheckCtxt, ctor: &Constructor, ty: Ty) -> u64 {
 ///
 /// For instance, a tuple pattern (43u32, 'a') has sub pattern types [u32, char].
 fn constructor_sub_pattern_tys<'a, 'tcx: 'a>(cx: &MatchCheckCtxt<'a, 'tcx>,
-                                             ctor: &Constructor,
+                                             ctor: &Constructor<'tcx>,
                                              ty: Ty<'tcx>) -> Vec<Ty<'tcx>>
 {
     debug!("constructor_sub_pattern_tys({:#?}, {:?})", ctor, ty);
@@ -1361,14 +1381,14 @@ fn constructor_sub_pattern_tys<'a, 'tcx: 'a>(cx: &MatchCheckCtxt<'a, 'tcx>,
             Slice(length) => (0..length).map(|_| ty).collect(),
             ConstantValue(_) => vec![],
             _ => bug!("bad slice pattern {:?} {:?}", ctor, ty)
-        },
+        }
         ty::Ref(_, rty, _) => vec![rty],
         ty::Adt(adt, substs) => {
             if adt.is_box() {
                 // Use T as the sub pattern type of Box<T>.
                 vec![substs.type_at(0)]
             } else {
-                adt.variants[ctor.variant_index_for_adt(adt)].fields.iter().map(|field| {
+                adt.variants[ctor.variant_index_for_adt(cx, adt)].fields.iter().map(|field| {
                     let is_visible = adt.is_enum()
                         || field.vis.is_accessible_from(cx.module, cx.tcx);
                     if is_visible {
@@ -1421,7 +1441,7 @@ fn slice_pat_covered_by_const<'tcx>(
             alloc.get_bytes(&tcx, ptr, Size::from_bytes(n)).unwrap()
         },
         // a slice fat pointer to a zero length slice
-        (ConstValue::ScalarPair(Scalar::Bits { .. }, n), ty::Slice(t)) => {
+        (ConstValue::Slice(Scalar::Bits { .. }, 0), ty::Slice(t)) => {
             if *t != tcx.types.u8 {
                 // FIXME(oli-obk): can't mix const patterns with slice patterns and get
                 // any sort of exhaustiveness/unreachable check yet
@@ -1429,11 +1449,10 @@ fn slice_pat_covered_by_const<'tcx>(
                 // are definitely unreachable.
                 return Ok(false);
             }
-            assert_eq!(n.to_usize(&tcx).unwrap(), 0);
             &[]
         },
         //
-        (ConstValue::ScalarPair(Scalar::Ptr(ptr), n), ty::Slice(t)) => {
+        (ConstValue::Slice(Scalar::Ptr(ptr), n), ty::Slice(t)) => {
             if *t != tcx.types.u8 {
                 // FIXME(oli-obk): can't mix const patterns with slice patterns and get
                 // any sort of exhaustiveness/unreachable check yet
@@ -1441,7 +1460,6 @@ fn slice_pat_covered_by_const<'tcx>(
                 // are definitely unreachable.
                 return Ok(false);
             }
-            let n = n.to_usize(&tcx).unwrap();
             tcx.alloc_map
                 .lock()
                 .unwrap_memory(ptr.alloc_id)
@@ -1602,7 +1620,7 @@ fn split_grouped_constructors<'p, 'a: 'p, 'tcx: 'a>(
     split_ctors
 }
 
-/// Check whether there exists any shared value in either `ctor` or `pat` by intersecting them.
+/// Checks whether there exists any shared value in either `ctor` or `pat` by intersecting them.
 fn constructor_intersects_pattern<'p, 'a: 'p, 'tcx: 'a>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     ctor: &Constructor<'tcx>,
@@ -1773,12 +1791,12 @@ fn specialize<'p, 'a: 'p, 'tcx: 'a>(
                         },
                         ty::TyKind::Slice(t) => {
                             match value.val {
-                                ConstValue::ScalarPair(ptr, n) => (
+                                ConstValue::Slice(ptr, n) => (
                                     ptr.to_ptr().ok().map(|ptr| (
                                         ptr,
                                         cx.tcx.alloc_map.lock().unwrap_memory(ptr.alloc_id),
                                     )),
-                                    n.to_bits(cx.tcx.data_layout.pointer_size).unwrap() as u64,
+                                    n,
                                     t,
                                 ),
                                 _ => span_bug!(
diff --git a/src/librustc_mir/hair/pattern/check_match.rs b/src/librustc_mir/hair/pattern/check_match.rs
index 10213beba2a6d..7c44d1bf2c936 100644
--- a/src/librustc_mir/hair/pattern/check_match.rs
+++ b/src/librustc_mir/hair/pattern/check_match.rs
@@ -28,22 +28,10 @@ use syntax::ast;
 use syntax::ptr::P;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
 
-struct OuterVisitor<'a, 'tcx: 'a> { tcx: TyCtxt<'a, 'tcx, 'tcx> }
-
-impl<'a, 'tcx> Visitor<'tcx> for OuterVisitor<'a, 'tcx> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
-        NestedVisitorMap::OnlyBodies(&self.tcx.hir())
-    }
-
-    fn visit_body(&mut self, body: &'tcx hir::Body) {
-        intravisit::walk_body(self, body);
-        let def_id = self.tcx.hir().body_owner_def_id(body.id());
-        let _ = self.tcx.check_match(def_id);
-    }
-}
-
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
-    tcx.hir().krate().visit_all_item_likes(&mut OuterVisitor { tcx }.as_deep_visitor());
+    for def_id in tcx.body_owners() {
+        tcx.ensure().check_match(def_id);
+    }
     tcx.sess.abort_if_errors();
 }
 
@@ -214,7 +202,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
 
             // Then, if the match has no arms, check whether the scrutinee
             // is uninhabited.
-            let pat_ty = self.tables.node_id_to_type(scrut.hir_id);
+            let pat_ty = self.tables.node_type(scrut.hir_id);
             let module = self.tcx.hir().get_module_parent(scrut.id);
             if inlined_arms.is_empty() {
                 let scrutinee_is_uninhabited = if self.tcx.features().exhaustive_patterns {
@@ -241,13 +229,13 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
                 return;
             }
 
-            let matrix: Matrix = inlined_arms
+            let matrix: Matrix<'_, '_> = inlined_arms
                 .iter()
                 .filter(|&&(_, guard)| guard.is_none())
                 .flat_map(|arm| &arm.0)
                 .map(|pat| smallvec![pat.0])
                 .collect();
-            let scrut_ty = self.tables.node_id_to_type(scrut.hir_id);
+            let scrut_ty = self.tables.node_type(scrut.hir_id);
             check_exhaustive(cx, scrut_ty, scrut.span, &matrix);
         })
     }
@@ -260,7 +248,7 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
                                                 self.tables);
             let pattern = patcx.lower_pattern(pat);
             let pattern_ty = pattern.ty;
-            let pats: Matrix = vec![smallvec![
+            let pats: Matrix<'_, '_> = vec![smallvec![
                 expand_pattern(cx, pattern)
             ]].into_iter().collect();
 
@@ -295,9 +283,9 @@ impl<'a, 'tcx> MatchVisitor<'a, 'tcx> {
     }
 }
 
-fn check_for_bindings_named_same_as_variants(cx: &MatchVisitor, pat: &Pat) {
+fn check_for_bindings_named_same_as_variants(cx: &MatchVisitor<'_, '_>, pat: &Pat) {
     pat.walk(|p| {
-        if let PatKind::Binding(_, _, ident, None) = p.node {
+        if let PatKind::Binding(_, _, _, ident, None) = p.node {
             if let Some(&bm) = cx.tables.pat_binding_modes().get(p.hir_id) {
                 if bm != ty::BindByValue(hir::MutImmutable) {
                     // Nothing to check.
@@ -313,7 +301,7 @@ fn check_for_bindings_named_same_as_variants(cx: &MatchVisitor, pat: &Pat) {
                             "pattern binding `{}` is named the same as one \
                             of the variants of the type `{}`",
                             ident, ty_path);
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             p.span,
                             "to match on the variant, qualify the path",
                             format!("{}::{}", ty_path, ident),
@@ -387,7 +375,7 @@ fn check_arms<'a, 'tcx>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
                                 },
                                 _ => bug!(),
                             }
-                        },
+                        }
 
                         hir::MatchSource::ForLoopDesugar |
                         hir::MatchSource::Normal => {
@@ -403,7 +391,7 @@ fn check_arms<'a, 'tcx>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
                                 err.span_label(catchall, "matches any value");
                             }
                             err.emit();
-                        },
+                        }
 
                         // Unreachable patterns in try expressions occur when one of the arms
                         // are an uninhabited type. Which is OK.
@@ -448,7 +436,7 @@ fn check_exhaustive<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
                     let (tail, head) = witnesses.split_last().unwrap();
                     let head: Vec<_> = head.iter().map(|w| w.to_string()).collect();
                     format!("`{}` and `{}`", head.join("`, `"), tail)
-                },
+                }
                 _ => {
                     let (head, tail) = witnesses.split_at(LIMIT);
                     let head: Vec<_> = head.iter().map(|w| w.to_string()).collect();
@@ -458,7 +446,7 @@ fn check_exhaustive<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
 
             let label_text = match witnesses.len() {
                 1 => format!("pattern {} not covered", joined_patterns),
-                _ => format!("patterns {} not covered", joined_patterns)
+                _ => format!("patterns {} not covered", joined_patterns),
             };
             create_e0004(cx.tcx.sess, sp,
                             format!("non-exhaustive patterns: {} not covered",
@@ -468,13 +456,13 @@ fn check_exhaustive<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
         }
         NotUseful => {
             // This is good, wildcard pattern isn't reachable
-        },
+        }
         _ => bug!()
     }
 }
 
 // Legality of move bindings checking
-fn check_legality_of_move_bindings(cx: &MatchVisitor,
+fn check_legality_of_move_bindings(cx: &MatchVisitor<'_, '_>,
                                    has_guard: bool,
                                    pats: &[P<Pat>]) {
     let mut by_ref_span = None;
@@ -515,11 +503,11 @@ fn check_legality_of_move_bindings(cx: &MatchVisitor,
 
     for pat in pats {
         pat.walk(|p| {
-            if let PatKind::Binding(_, _, _, ref sub) = p.node {
+            if let PatKind::Binding(_, _, _, _, ref sub) = p.node {
                 if let Some(&bm) = cx.tables.pat_binding_modes().get(p.hir_id) {
                     match bm {
                         ty::BindByValue(..) => {
-                            let pat_ty = cx.tables.node_id_to_type(p.hir_id);
+                            let pat_ty = cx.tables.node_type(p.hir_id);
                             if !pat_ty.is_copy_modulo_regions(cx.tcx, cx.param_env, pat.span) {
                                 check_move(p, sub.as_ref().map(|p| &**p), span_vec);
                             }
@@ -549,11 +537,10 @@ fn check_legality_of_move_bindings(cx: &MatchVisitor,
     }
 }
 
-/// Ensures that a pattern guard doesn't borrow by mutable reference or
-/// assign.
-///
-/// FIXME: this should be done by borrowck.
-fn check_for_mutation_in_guard(cx: &MatchVisitor, guard: &hir::Guard) {
+/// Ensures that a pattern guard doesn't borrow by mutable reference or assign.
+//
+// FIXME: this should be done by borrowck.
+fn check_for_mutation_in_guard(cx: &MatchVisitor<'_, '_>, guard: &hir::Guard) {
     let mut checker = MutationChecker {
         cx,
     };
@@ -573,13 +560,13 @@ struct MutationChecker<'a, 'tcx: 'a> {
 }
 
 impl<'a, 'tcx> Delegate<'tcx> for MutationChecker<'a, 'tcx> {
-    fn matched_pat(&mut self, _: &Pat, _: &cmt_, _: euv::MatchMode) {}
-    fn consume(&mut self, _: ast::NodeId, _: Span, _: &cmt_, _: ConsumeMode) {}
-    fn consume_pat(&mut self, _: &Pat, _: &cmt_, _: ConsumeMode) {}
+    fn matched_pat(&mut self, _: &Pat, _: &cmt_<'_>, _: euv::MatchMode) {}
+    fn consume(&mut self, _: ast::NodeId, _: Span, _: &cmt_<'_>, _: ConsumeMode) {}
+    fn consume_pat(&mut self, _: &Pat, _: &cmt_<'_>, _: ConsumeMode) {}
     fn borrow(&mut self,
               _: ast::NodeId,
               span: Span,
-              _: &cmt_,
+              _: &cmt_<'_>,
               _: ty::Region<'tcx>,
               kind:ty:: BorrowKind,
               _: LoanCause) {
@@ -600,7 +587,7 @@ impl<'a, 'tcx> Delegate<'tcx> for MutationChecker<'a, 'tcx> {
         }
     }
     fn decl_without_init(&mut self, _: ast::NodeId, _: Span) {}
-    fn mutate(&mut self, _: ast::NodeId, span: Span, _: &cmt_, mode: MutateMode) {
+    fn mutate(&mut self, _: ast::NodeId, span: Span, _: &cmt_<'_>, mode: MutateMode) {
         match mode {
             MutateMode::JustWrite | MutateMode::WriteAndRead => {
                 struct_span_err!(self.cx.tcx.sess, span, E0302, "cannot assign in a pattern guard")
@@ -615,7 +602,7 @@ impl<'a, 'tcx> Delegate<'tcx> for MutationChecker<'a, 'tcx> {
 /// Forbids bindings in `@` patterns. This is necessary for memory safety,
 /// because of the way rvalues are handled in the borrow check. (See issue
 /// #14587.)
-fn check_legality_of_bindings_in_at_patterns(cx: &MatchVisitor, pat: &Pat) {
+fn check_legality_of_bindings_in_at_patterns(cx: &MatchVisitor<'_, '_>, pat: &Pat) {
     AtBindingPatternVisitor { cx: cx, bindings_allowed: true }.visit_pat(pat);
 }
 
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index 8991a90737c7e..4d571f4f78296 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -1,4 +1,4 @@
-//! Code to validate patterns/matches
+//! Validation of patterns/matches.
 
 mod _match;
 mod check_match;
@@ -6,16 +6,16 @@ mod check_match;
 pub use self::check_match::check_crate;
 pub(crate) use self::check_match::check_match;
 
-use const_eval::{const_field, const_variant_index};
+use crate::const_eval::{const_field, const_variant_index};
 
-use hair::util::UserAnnotatedTyHelpers;
-use hair::constant::*;
+use crate::hair::util::UserAnnotatedTyHelpers;
+use crate::hair::constant::*;
 
 use rustc::mir::{fmt_const_val, Field, BorrowKind, Mutability};
-use rustc::mir::{ProjectionElem, UserTypeProjection};
+use rustc::mir::{UserTypeProjection};
 use rustc::mir::interpret::{Scalar, GlobalId, ConstValue, sign_extend};
-use rustc::ty::{self, Region, TyCtxt, AdtDef, Ty, Lift};
-use rustc::ty::{CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, UserTypeAnnotation};
+use rustc::ty::{self, Region, TyCtxt, AdtDef, Ty, Lift, UserType};
+use rustc::ty::{CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations};
 use rustc::ty::subst::{Substs, Kind};
 use rustc::ty::layout::VariantIdx;
 use rustc::hir::{self, PatKind, RangeEnd};
@@ -58,62 +58,70 @@ pub struct Pattern<'tcx> {
 }
 
 
-#[derive(Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct PatternTypeProjection<'tcx> {
-    pub base: CanonicalUserTypeAnnotation<'tcx>,
-    pub projs: Vec<ProjectionElem<'tcx, (), ()>>,
+    pub user_ty: CanonicalUserType<'tcx>,
 }
 
 impl<'tcx> PatternTypeProjection<'tcx> {
-    pub(crate) fn from_user_type(user_annotation: CanonicalUserTypeAnnotation<'tcx>) -> Self {
+    pub(crate) fn from_user_type(user_annotation: CanonicalUserType<'tcx>) -> Self {
         Self {
-            base: user_annotation,
-            projs: Vec::new(),
+            user_ty: user_annotation,
         }
     }
 
     pub(crate) fn user_ty(
         self,
         annotations: &mut CanonicalUserTypeAnnotations<'tcx>,
+        inferred_ty: Ty<'tcx>,
         span: Span,
     ) -> UserTypeProjection<'tcx> {
         UserTypeProjection {
-            base: annotations.push((span, self.base)),
-            projs: self.projs
+            base: annotations.push(CanonicalUserTypeAnnotation {
+                span,
+                user_ty: self.user_ty,
+                inferred_ty,
+            }),
+            projs: Vec::new(),
         }
     }
 }
 
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct Ascription<'tcx> {
+    pub user_ty: PatternTypeProjection<'tcx>,
+    /// Variance to use when relating the type `user_ty` to the **type of the value being
+    /// matched**. Typically, this is `Variance::Covariant`, since the value being matched must
+    /// have a type that is some subtype of the ascribed type.
+    ///
+    /// Note that this variance does not apply for any bindings within subpatterns. The type
+    /// assigned to those bindings must be exactly equal to the `user_ty` given here.
+    ///
+    /// The only place where this field is not `Covariant` is when matching constants, where
+    /// we currently use `Contravariant` -- this is because the constant type just needs to
+    /// be "comparable" to the type of the input value. So, for example:
+    ///
+    /// ```text
+    /// match x { "foo" => .. }
+    /// ```
+    ///
+    /// requires that `&'static str <: T_x`, where `T_x` is the type of `x`. Really, we should
+    /// probably be checking for a `PartialEq` impl instead, but this preserves the behavior
+    /// of the old type-check for now. See #57280 for details.
+    pub variance: ty::Variance,
+    pub user_ty_span: Span,
+}
+
 #[derive(Clone, Debug)]
 pub enum PatternKind<'tcx> {
     Wild,
 
     AscribeUserType {
-        user_ty: PatternTypeProjection<'tcx>,
+        ascription: Ascription<'tcx>,
         subpattern: Pattern<'tcx>,
-        /// Variance to use when relating the type `user_ty` to the **type of the value being
-        /// matched**. Typically, this is `Variance::Covariant`, since the value being matched must
-        /// have a type that is some subtype of the ascribed type.
-        ///
-        /// Note that this variance does not apply for any bindings within subpatterns. The type
-        /// assigned to those bindings must be exactly equal to the `user_ty` given here.
-        ///
-        /// The only place where this field is not `Covariant` is when matching constants, where
-        /// we currently use `Contravariant` -- this is because the constant type just needs to
-        /// be "comparable" to the type of the input value. So, for example:
-        ///
-        /// ```text
-        /// match x { "foo" => .. }
-        /// ```
-        ///
-        /// requires that `&'static str <: T_x`, where `T_x` is the type of `x`. Really, we should
-        /// probably be checking for a `PartialEq` impl instead, but this preserves the behavior
-        /// of the old type-check for now. See #57280 for details.
-        variance: ty::Variance,
-        user_ty_span: Span,
     },
 
-    /// x, ref x, x @ P, etc
+    /// `x`, `ref x`, `x @ P`, etc.
     Binding {
         mutability: Mutability,
         name: ast::Name,
@@ -123,7 +131,8 @@ pub enum PatternKind<'tcx> {
         subpattern: Option<Pattern<'tcx>>,
     },
 
-    /// Foo(...) or Foo{...} or Foo, where `Foo` is a variant name from an adt with >1 variants
+    /// `Foo(...)` or `Foo{...}` or `Foo`, where `Foo` is a variant name from an ADT with
+    /// multiple variants.
     Variant {
         adt_def: &'tcx AdtDef,
         substs: &'tcx Substs<'tcx>,
@@ -131,12 +140,13 @@ pub enum PatternKind<'tcx> {
         subpatterns: Vec<FieldPattern<'tcx>>,
     },
 
-    /// (...), Foo(...), Foo{...}, or Foo, where `Foo` is a variant name from an adt with 1 variant
+    /// `(...)`, `Foo(...)`, `Foo{...}`, or `Foo`, where `Foo` is a variant name from an ADT with
+    /// a single variant.
     Leaf {
         subpatterns: Vec<FieldPattern<'tcx>>,
     },
 
-    /// box P, &P, &mut P, etc
+    /// `box P`, `&P`, `&mut P`, etc.
     Deref {
         subpattern: Pattern<'tcx>,
     },
@@ -147,7 +157,7 @@ pub enum PatternKind<'tcx> {
 
     Range(PatternRange<'tcx>),
 
-    /// matches against a slice, checking the length and extracting elements.
+    /// Matches against a slice, checking the length and extracting elements.
     /// irrefutable when there is a slice pattern and both `prefix` and `suffix` are empty.
     /// e.g., `&[ref xs..]`.
     Slice {
@@ -156,7 +166,7 @@ pub enum PatternKind<'tcx> {
         suffix: Vec<Pattern<'tcx>>,
     },
 
-    /// fixed match against an array, irrefutable
+    /// Fixed match against an array; irrefutable.
     Array {
         prefix: Vec<Pattern<'tcx>>,
         slice: Option<Pattern<'tcx>>,
@@ -164,7 +174,7 @@ pub enum PatternKind<'tcx> {
     },
 }
 
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub struct PatternRange<'tcx> {
     pub lo: ty::Const<'tcx>,
     pub hi: ty::Const<'tcx>,
@@ -173,7 +183,7 @@ pub struct PatternRange<'tcx> {
 }
 
 impl<'tcx> fmt::Display for Pattern<'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self.kind {
             PatternKind::Wild => write!(f, "_"),
             PatternKind::AscribeUserType { ref subpattern, .. } =>
@@ -391,8 +401,21 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
             )
     }
 
+    fn lower_range_expr(
+        &mut self,
+        expr: &'tcx hir::Expr,
+    ) -> (PatternKind<'tcx>, Option<Ascription<'tcx>>) {
+        match self.lower_lit(expr) {
+            PatternKind::AscribeUserType {
+                ascription: lo_ascription,
+                subpattern: Pattern { kind: box kind, .. },
+            } => (kind, Some(lo_ascription)),
+            kind => (kind, None),
+        }
+    }
+
     fn lower_pattern_unadjusted(&mut self, pat: &'tcx hir::Pat) -> Pattern<'tcx> {
-        let mut ty = self.tables.node_id_to_type(pat.hir_id);
+        let mut ty = self.tables.node_type(pat.hir_id);
 
         let kind = match pat.node {
             PatKind::Wild => PatternKind::Wild,
@@ -400,9 +423,11 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
             PatKind::Lit(ref value) => self.lower_lit(value),
 
             PatKind::Range(ref lo_expr, ref hi_expr, end) => {
-                match (self.lower_lit(lo_expr), self.lower_lit(hi_expr)) {
-                    (PatternKind::Constant { value: lo },
-                     PatternKind::Constant { value: hi }) => {
+                let (lo, lo_ascription) = self.lower_range_expr(lo_expr);
+                let (hi, hi_ascription) = self.lower_range_expr(hi_expr);
+
+                let mut kind = match (lo, hi) {
+                    (PatternKind::Constant { value: lo }, PatternKind::Constant { value: hi }) => {
                         use std::cmp::Ordering;
                         let cmp = compare_const_vals(
                             self.tcx,
@@ -450,9 +475,33 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                                 PatternKind::Wild
                             }
                         }
+                    },
+                    ref pats => {
+                        self.tcx.sess.delay_span_bug(
+                            pat.span,
+                            &format!(
+                                "found bad range pattern `{:?}` outside of error recovery",
+                                pats,
+                            ),
+                        );
+
+                        PatternKind::Wild
+                    },
+                };
+
+                // If we are handling a range with associated constants (e.g.
+                // `Foo::<'a>::A..=Foo::B`), we need to put the ascriptions for the associated
+                // constants somewhere. Have them on the range pattern.
+                for ascription in &[lo_ascription, hi_ascription] {
+                    if let Some(ascription) = ascription {
+                        kind = PatternKind::AscribeUserType {
+                            ascription: *ascription,
+                            subpattern: Pattern { span: pat.span, ty, kind: Box::new(kind), },
+                        };
                     }
-                    _ => PatternKind::Wild
                 }
+
+                kind
             }
 
             PatKind::Path(ref qpath) => {
@@ -510,8 +559,8 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                 }
             }
 
-            PatKind::Binding(_, id, ident, ref sub) => {
-                let var_ty = self.tables.node_id_to_type(pat.hir_id);
+            PatKind::Binding(_, id, _, ident, ref sub) => {
+                let var_ty = self.tables.node_type(pat.hir_id);
                 if let ty::Error = var_ty.sty {
                     // Avoid ICE
                     return Pattern { span: pat.span, ty, kind: Box::new(PatternKind::Wild) };
@@ -728,9 +777,11 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                     ty,
                     kind: Box::new(kind),
                 },
-                user_ty: PatternTypeProjection::from_user_type(user_ty),
-                user_ty_span: span,
-                variance: ty::Variance::Covariant,
+                ascription: Ascription {
+                    user_ty: PatternTypeProjection::from_user_type(user_ty),
+                    user_ty_span: span,
+                    variance: ty::Variance::Covariant,
+                },
             };
         }
 
@@ -739,13 +790,13 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
 
     /// Takes a HIR Path. If the path is a constant, evaluates it and feeds
     /// it to `const_to_pat`. Any other path (like enum variants without fields)
-    /// is converted to the corresponding pattern via `lower_variant_or_leaf`
+    /// is converted to the corresponding pattern via `lower_variant_or_leaf`.
     fn lower_path(&mut self,
                   qpath: &hir::QPath,
                   id: hir::HirId,
                   span: Span)
                   -> Pattern<'tcx> {
-        let ty = self.tables.node_id_to_type(id);
+        let ty = self.tables.node_type(id);
         let def = self.tables.qpath_def(qpath, id);
         let is_associated_const = match def {
             Def::AssociatedConst(_) => true,
@@ -780,11 +831,13 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                                         kind: Box::new(
                                             PatternKind::AscribeUserType {
                                                 subpattern: pattern,
-                                                /// Note that use `Contravariant` here. See the
-                                                /// `variance` field documentation for details.
-                                                variance: ty::Variance::Contravariant,
-                                                user_ty,
-                                                user_ty_span: span,
+                                                ascription: Ascription {
+                                                    /// Note that use `Contravariant` here. See the
+                                                    /// `variance` field documentation for details.
+                                                    variance: ty::Variance::Contravariant,
+                                                    user_ty,
+                                                    user_ty_span: span,
+                                                },
                                             }
                                         ),
                                         ty: value.ty,
@@ -823,8 +876,8 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
     }
 
     /// Converts literals, paths and negation of literals to patterns.
-    /// The special case for negation exists to allow things like -128i8
-    /// which would overflow if we tried to evaluate 128i8 and then negate
+    /// The special case for negation exists to allow things like `-128_i8`
+    /// which would overflow if we tried to evaluate `128_i8` and then negate
     /// afterwards.
     fn lower_lit(&mut self, expr: &'tcx hir::Expr) -> PatternKind<'tcx> {
         match expr.node {
@@ -873,7 +926,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
 
     /// Converts an evaluated constant to a pattern (if possible).
     /// This means aggregate values (like structs and enums) are converted
-    /// to a pattern that matches the value (as if you'd compare via eq).
+    /// to a pattern that matches the value (as if you'd compared via equality).
     fn const_to_pat(
         &self,
         instance: ty::Instance<'tcx>,
@@ -885,7 +938,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
         let adt_subpattern = |i, variant_opt| {
             let field = Field::new(i);
             let val = const_field(
-                self.tcx, self.param_env, instance,
+                self.tcx, self.param_env,
                 variant_opt, field, cv,
             ).expect("field access failed");
             self.const_to_pat(instance, val, id, span)
@@ -912,7 +965,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                 PatternKind::Constant {
                     value: cv,
                 }
-            },
+            }
             ty::Adt(adt_def, _) if adt_def.is_union() => {
                 // Matching on union fields is unsafe, we can't hide it in constants
                 self.tcx.sess.span_err(span, "cannot use unions in constant patterns");
@@ -925,10 +978,10 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                                     self.tcx.item_path_str(adt_def.did));
                 self.tcx.sess.span_err(span, &msg);
                 PatternKind::Wild
-            },
+            }
             ty::Adt(adt_def, substs) if adt_def.is_enum() => {
                 let variant_index = const_variant_index(
-                    self.tcx, self.param_env, instance, cv
+                    self.tcx, self.param_env, cv
                 ).expect("const_variant_index failed");
                 let subpatterns = adt_subpatterns(
                     adt_def.variants[variant_index].fields.len(),
@@ -940,7 +993,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                     variant_index,
                     subpatterns,
                 }
-            },
+            }
             ty::Adt(adt_def, _) => {
                 let struct_var = adt_def.non_enum_variant();
                 PatternKind::Leaf {
@@ -965,7 +1018,7 @@ impl<'a, 'tcx> PatternContext<'a, 'tcx> {
                 PatternKind::Constant {
                     value: cv,
                 }
-            },
+            }
         };
 
         Pattern {
@@ -1040,7 +1093,7 @@ macro_rules! CloneImpls {
 CloneImpls!{ <'tcx>
     Span, Field, Mutability, ast::Name, ast::NodeId, usize, ty::Const<'tcx>,
     Region<'tcx>, Ty<'tcx>, BindingMode, &'tcx AdtDef,
-    &'tcx Substs<'tcx>, &'tcx Kind<'tcx>, UserTypeAnnotation<'tcx>,
+    &'tcx Substs<'tcx>, &'tcx Kind<'tcx>, UserType<'tcx>,
     UserTypeProjection<'tcx>, PatternTypeProjection<'tcx>
 }
 
@@ -1077,14 +1130,18 @@ impl<'tcx> PatternFoldable<'tcx> for PatternKind<'tcx> {
             PatternKind::Wild => PatternKind::Wild,
             PatternKind::AscribeUserType {
                 ref subpattern,
-                variance,
-                ref user_ty,
-                user_ty_span,
+                ascription: Ascription {
+                    variance,
+                    ref user_ty,
+                    user_ty_span,
+                },
             } => PatternKind::AscribeUserType {
                 subpattern: subpattern.fold_with(folder),
-                user_ty: user_ty.fold_with(folder),
-                variance,
-                user_ty_span,
+                ascription: Ascription {
+                    user_ty: user_ty.fold_with(folder),
+                    variance,
+                    user_ty_span,
+                },
             },
             PatternKind::Binding {
                 mutability,
@@ -1195,19 +1252,19 @@ pub fn compare_const_vals<'a, 'gcx, 'tcx>(
                 let l = ::rustc_apfloat::ieee::Single::from_bits(a);
                 let r = ::rustc_apfloat::ieee::Single::from_bits(b);
                 l.partial_cmp(&r)
-            },
+            }
             ty::Float(ast::FloatTy::F64) => {
                 let l = ::rustc_apfloat::ieee::Double::from_bits(a);
                 let r = ::rustc_apfloat::ieee::Double::from_bits(b);
                 l.partial_cmp(&r)
-            },
+            }
             ty::Int(_) => {
                 let layout = tcx.layout_of(ty).ok()?;
                 assert!(layout.abi.is_signed());
                 let a = sign_extend(a, layout.size);
                 let b = sign_extend(b, layout.size);
                 Some((a as i128).cmp(&(b as i128)))
-            },
+            }
             _ => Some(a.cmp(&b)),
         }
     }
@@ -1215,25 +1272,21 @@ pub fn compare_const_vals<'a, 'gcx, 'tcx>(
     if let ty::Str = ty.value.sty {
         match (a.val, b.val) {
             (
-                ConstValue::ScalarPair(
+                ConstValue::Slice(
                     Scalar::Ptr(ptr_a),
                     len_a,
                 ),
-                ConstValue::ScalarPair(
+                ConstValue::Slice(
                     Scalar::Ptr(ptr_b),
                     len_b,
                 ),
             ) if ptr_a.offset.bytes() == 0 && ptr_b.offset.bytes() == 0 => {
-                if let Ok(len_a) = len_a.to_bits(tcx.data_layout.pointer_size) {
-                    if let Ok(len_b) = len_b.to_bits(tcx.data_layout.pointer_size) {
-                        if len_a == len_b {
-                            let map = tcx.alloc_map.lock();
-                            let alloc_a = map.unwrap_memory(ptr_a.alloc_id);
-                            let alloc_b = map.unwrap_memory(ptr_b.alloc_id);
-                            if alloc_a.bytes.len() as u128 == len_a {
-                                return from_bool(alloc_a == alloc_b);
-                            }
-                        }
+                if len_a == len_b {
+                    let map = tcx.alloc_map.lock();
+                    let alloc_a = map.unwrap_memory(ptr_a.alloc_id);
+                    let alloc_b = map.unwrap_memory(ptr_b.alloc_id);
+                    if alloc_a.bytes.len() as u64 == len_a {
+                        return from_bool(alloc_a == alloc_b);
                     }
                 }
             }
diff --git a/src/librustc_mir/hair/util.rs b/src/librustc_mir/hair/util.rs
index f0f8263b64de5..4618cd42686fa 100644
--- a/src/librustc_mir/hair/util.rs
+++ b/src/librustc_mir/hair/util.rs
@@ -1,5 +1,5 @@
 use rustc::hir;
-use rustc::ty::{self, CanonicalUserTypeAnnotation, TyCtxt, UserTypeAnnotation};
+use rustc::ty::{self, CanonicalUserType, TyCtxt, UserType};
 
 crate trait UserAnnotatedTyHelpers<'gcx: 'tcx, 'tcx> {
     fn tcx(&self) -> TyCtxt<'_, 'gcx, 'tcx>;
@@ -12,13 +12,13 @@ crate trait UserAnnotatedTyHelpers<'gcx: 'tcx, 'tcx> {
     fn user_substs_applied_to_ty_of_hir_id(
         &self,
         hir_id: hir::HirId,
-    ) -> Option<CanonicalUserTypeAnnotation<'tcx>> {
+    ) -> Option<CanonicalUserType<'tcx>> {
         let user_provided_types = self.tables().user_provided_types();
         let mut user_ty = *user_provided_types.get(hir_id)?;
         debug!("user_subts_applied_to_ty_of_hir_id: user_ty={:?}", user_ty);
-        match &self.tables().node_id_to_type(hir_id).sty {
+        match &self.tables().node_type(hir_id).sty {
             ty::Adt(adt_def, ..) => {
-                if let UserTypeAnnotation::TypeOf(ref mut did, _) = &mut user_ty.value {
+                if let UserType::TypeOf(ref mut did, _) = &mut user_ty.value {
                     *did = adt_def.did;
                 }
                 Some(user_ty)
diff --git a/src/librustc_mir/interpret/cast.rs b/src/librustc_mir/interpret/cast.rs
index 190a381cf52a5..ce62d79e585a8 100644
--- a/src/librustc_mir/interpret/cast.rs
+++ b/src/librustc_mir/interpret/cast.rs
@@ -9,7 +9,7 @@ use rustc::mir::interpret::{
 use rustc::mir::CastKind;
 use rustc_apfloat::Float;
 
-use super::{EvalContext, Machine, PlaceTy, OpTy, Immediate};
+use super::{EvalContext, Machine, PlaceTy, OpTy, ImmTy, Immediate};
 
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
     fn type_is_fat_ptr(&self, ty: Ty<'tcx>) -> bool {
@@ -109,11 +109,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                 // The src operand does not matter, just its type
                 match src.layout.ty.sty {
                     ty::Closure(def_id, substs) => {
-                        let substs = self.tcx.subst_and_normalize_erasing_regions(
-                            self.substs(),
-                            ty::ParamEnv::reveal_all(),
-                            &substs,
-                        );
+                        let substs = self.subst_and_normalize_erasing_regions(substs)?;
                         let instance = ty::Instance::resolve_closure(
                             *self.tcx,
                             def_id,
@@ -376,7 +372,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                             assert_eq!(src.layout.fields.offset(i).bytes(), 0);
                             assert_eq!(src_field_layout.size, src.layout.size);
                             // just sawp out the layout
-                            OpTy { op: src.op, layout: src_field_layout }
+                            OpTy::from(ImmTy { imm: src.to_immediate(), layout: src_field_layout })
                         }
                     };
                     if src_field.layout.ty == dst_field.layout.ty {
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 19362b6cfdb1c..0c1b5d65b8b68 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::fmt::Write;
 use std::mem;
 
@@ -54,7 +55,7 @@ pub struct Frame<'mir, 'tcx: 'mir, Tag=(), Extra=()> {
     /// The MIR for the function called on this frame.
     pub mir: &'mir mir::Mir<'tcx>,
 
-    /// The def_id and substs of the current function
+    /// The def_id and substs of the current function.
     pub instance: ty::Instance<'tcx>,
 
     /// The span of the call site.
@@ -63,7 +64,7 @@ pub struct Frame<'mir, 'tcx: 'mir, Tag=(), Extra=()> {
     ////////////////////////////////////////////////////////////////////////////////
     // Return place and locals
     ////////////////////////////////////////////////////////////////////////////////
-    /// Work to perform when returning from this function
+    /// Work to perform when returning from this function.
     pub return_to_block: StackPopCleanup,
 
     /// The location where the result of the current stack frame should be written to,
@@ -75,7 +76,7 @@ pub struct Frame<'mir, 'tcx: 'mir, Tag=(), Extra=()> {
     /// The locals are stored as `Option<Value>`s.
     /// `None` represents a local that is currently dead, while a live local
     /// can either directly contain `Scalar` or refer to some part of an `Allocation`.
-    pub locals: IndexVec<mir::Local, LocalValue<Tag>>,
+    pub locals: IndexVec<mir::Local, LocalState<'tcx, Tag>>,
 
     ////////////////////////////////////////////////////////////////////////////////
     // Current position within the function
@@ -87,7 +88,7 @@ pub struct Frame<'mir, 'tcx: 'mir, Tag=(), Extra=()> {
     /// The index of the currently evaluated statement.
     pub stmt: usize,
 
-    /// Extra data for the machine
+    /// Extra data for the machine.
     pub extra: Extra,
 }
 
@@ -98,13 +99,21 @@ pub enum StackPopCleanup {
     /// we can validate it at that layout.
     Goto(Option<mir::BasicBlock>),
     /// Just do nohing: Used by Main and for the box_alloc hook in miri.
-    /// `cleanup` says whether locals are deallocated.  Static computation
+    /// `cleanup` says whether locals are deallocated. Static computation
     /// wants them leaked to intern what they need (and just throw away
     /// the entire `ecx` when it is done).
     None { cleanup: bool },
 }
 
-// State of a local variable
+/// State of a local variable including a memoized layout
+#[derive(Clone, PartialEq, Eq)]
+pub struct LocalState<'tcx, Tag=(), Id=AllocId> {
+    pub state: LocalValue<Tag, Id>,
+    /// Don't modify if `Some`, this is only used to prevent computing the layout twice
+    pub layout: Cell<Option<TyLayout<'tcx>>>,
+}
+
+/// State of a local variable
 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
 pub enum LocalValue<Tag=(), Id=AllocId> {
     Dead,
@@ -115,16 +124,16 @@ pub enum LocalValue<Tag=(), Id=AllocId> {
     Live(Operand<Tag, Id>),
 }
 
-impl<'tcx, Tag> LocalValue<Tag> {
+impl<'tcx, Tag> LocalState<'tcx, Tag> {
     pub fn access(&self) -> EvalResult<'tcx, &Operand<Tag>> {
-        match self {
+        match self.state {
             LocalValue::Dead => err!(DeadLocal),
             LocalValue::Live(ref val) => Ok(val),
         }
     }
 
     pub fn access_mut(&mut self) -> EvalResult<'tcx, &mut Operand<Tag>> {
-        match self {
+        match self.state {
             LocalValue::Dead => err!(DeadLocal),
             LocalValue::Live(ref mut val) => Ok(val),
         }
@@ -214,11 +223,21 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         self.frame().mir
     }
 
-    pub fn substs(&self) -> &'tcx Substs<'tcx> {
-        if let Some(frame) = self.stack.last() {
-            frame.instance.substs
-        } else {
-            Substs::empty()
+    pub(super) fn subst_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
+        &self,
+        substs: T,
+    ) -> EvalResult<'tcx, T> {
+        match self.stack.last() {
+            Some(frame) => Ok(self.tcx.subst_and_normalize_erasing_regions(
+                frame.instance.substs,
+                self.param_env,
+                &substs,
+            )),
+            None => if substs.needs_subst() {
+                err!(TooGeneric).into()
+            } else {
+                Ok(substs)
+            },
         }
     }
 
@@ -228,13 +247,9 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         substs: &'tcx Substs<'tcx>
     ) -> EvalResult<'tcx, ty::Instance<'tcx>> {
         trace!("resolve: {:?}, {:#?}", def_id, substs);
-        trace!("substs: {:#?}", self.substs());
         trace!("param_env: {:#?}", self.param_env);
-        let substs = self.tcx.subst_and_normalize_erasing_regions(
-            self.substs(),
-            self.param_env,
-            &substs,
-        );
+        let substs = self.subst_and_normalize_erasing_regions(substs)?;
+        trace!("substs: {:#?}", substs);
         ty::Instance::resolve(
             *self.tcx,
             self.param_env,
@@ -265,16 +280,30 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         }
         trace!("load mir {:?}", instance);
         match instance {
-            ty::InstanceDef::Item(def_id) => {
-                self.tcx.maybe_optimized_mir(def_id).ok_or_else(||
-                    EvalErrorKind::NoMirFor(self.tcx.item_path_str(def_id)).into()
-                )
-            }
+            ty::InstanceDef::Item(def_id) => if self.tcx.is_mir_available(did) {
+                Ok(self.tcx.optimized_mir(did))
+            } else {
+                err!(NoMirFor(self.tcx.item_path_str(def_id)))
+            },
             _ => Ok(self.tcx.instance_mir(instance)),
         }
     }
 
-    pub fn monomorphize<T: TypeFoldable<'tcx> + Subst<'tcx>>(
+    pub(super) fn monomorphize<T: TypeFoldable<'tcx> + Subst<'tcx>>(
+        &self,
+        t: T,
+    ) -> EvalResult<'tcx, T> {
+        match self.stack.last() {
+            Some(frame) => Ok(self.monomorphize_with_substs(t, frame.instance.substs)),
+            None => if t.needs_subst() {
+                err!(TooGeneric).into()
+            } else {
+                Ok(t)
+            },
+        }
+    }
+
+    fn monomorphize_with_substs<T: TypeFoldable<'tcx> + Subst<'tcx>>(
         &self,
         t: T,
         substs: &'tcx Substs<'tcx>
@@ -288,11 +317,21 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
     pub fn layout_of_local(
         &self,
         frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
-        local: mir::Local
+        local: mir::Local,
+        layout: Option<TyLayout<'tcx>>,
     ) -> EvalResult<'tcx, TyLayout<'tcx>> {
-        let local_ty = frame.mir.local_decls[local].ty;
-        let local_ty = self.monomorphize(local_ty, frame.instance.substs);
-        self.layout_of(local_ty)
+        match frame.locals[local].layout.get() {
+            None => {
+                let layout = crate::interpret::operand::from_known_layout(layout, || {
+                    let local_ty = frame.mir.local_decls[local].ty;
+                    let local_ty = self.monomorphize_with_substs(local_ty, frame.instance.substs);
+                    self.layout_of(local_ty)
+                })?;
+                frame.locals[local].layout.set(Some(layout));
+                Ok(layout)
+            }
+            Some(layout) => Ok(layout),
+        }
     }
 
     pub fn str_to_immediate(&mut self, s: &str) -> EvalResult<'tcx, Immediate<M::PointerTag>> {
@@ -300,7 +339,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         Ok(Immediate::new_slice(Scalar::Ptr(ptr), s.len() as u64, self))
     }
 
-    /// Return the actual dynamic size and alignment of the place at the given type.
+    /// Returns the actual dynamic size and alignment of the place at the given type.
     /// Only the "meta" (metadata) part of the place matters.
     /// This can fail to provide an answer for extern types.
     pub(super) fn size_and_align_of(
@@ -437,12 +476,16 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
             // We put some marker immediate into the locals that we later want to initialize.
             // This can be anything except for LocalValue::Dead -- because *that* is the
             // value we use for things that we know are initially dead.
-            let dummy =
-                LocalValue::Live(Operand::Immediate(Immediate::Scalar(ScalarMaybeUndef::Undef)));
+            let dummy = LocalState {
+                state: LocalValue::Live(Operand::Immediate(Immediate::Scalar(
+                    ScalarMaybeUndef::Undef,
+                ))),
+                layout: Cell::new(None),
+            };
             let mut locals = IndexVec::from_elem(dummy, &mir.local_decls);
             // Return place is handled specially by the `eval_place` functions, and the
             // entry in `locals` should never be used. Make it dead, to be sure.
-            locals[mir::RETURN_PLACE] = LocalValue::Dead;
+            locals[mir::RETURN_PLACE].state = LocalValue::Dead;
             // Now mark those locals as dead that we do not want to initialize
             match self.tcx.describe_def(instance.def_id()) {
                 // statics and constants don't have `Storage*` statements, no need to look for them
@@ -455,7 +498,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
                             match stmt.kind {
                                 StorageLive(local) |
                                 StorageDead(local) => {
-                                    locals[local] = LocalValue::Dead;
+                                    locals[local].state = LocalValue::Dead;
                                 }
                                 _ => {}
                             }
@@ -464,12 +507,14 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
                 },
             }
             // Finally, properly initialize all those that still have the dummy value
-            for (local, decl) in locals.iter_mut().zip(mir.local_decls.iter()) {
-                match *local {
+            for (idx, local) in locals.iter_enumerated_mut() {
+                match local.state {
                     LocalValue::Live(_) => {
-                        // This needs to be peoperly initialized.
-                        let layout = self.layout_of(self.monomorphize(decl.ty, instance.substs))?;
-                        *local = LocalValue::Live(self.uninit_operand(layout)?);
+                        // This needs to be properly initialized.
+                        let ty = self.monomorphize(mir.local_decls[idx].ty)?;
+                        let layout = self.layout_of(ty)?;
+                        local.state = LocalValue::Live(self.uninit_operand(layout)?);
+                        local.layout = Cell::new(Some(layout));
                     }
                     LocalValue::Dead => {
                         // Nothing to do
@@ -514,7 +559,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         }
         // Deallocate all locals that are backed by an allocation.
         for local in frame.locals {
-            self.deallocate_local(local)?;
+            self.deallocate_local(local.state)?;
         }
         // Validate the return value. Do this after deallocating so that we catch dangling
         // references.
@@ -562,10 +607,10 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
         trace!("{:?} is now live", local);
 
-        let layout = self.layout_of_local(self.frame(), local)?;
+        let layout = self.layout_of_local(self.frame(), local, None)?;
         let init = LocalValue::Live(self.uninit_operand(layout)?);
         // StorageLive *always* kills the value that's currently stored
-        Ok(mem::replace(&mut self.frame_mut().locals[local], init))
+        Ok(mem::replace(&mut self.frame_mut().locals[local].state, init))
     }
 
     /// Returns the old value of the local.
@@ -574,7 +619,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tc
         assert!(local != mir::RETURN_PLACE, "Cannot make return place dead");
         trace!("{:?} is now dead", local);
 
-        mem::replace(&mut self.frame_mut().locals[local], LocalValue::Dead)
+        mem::replace(&mut self.frame_mut().locals[local].state, LocalValue::Dead)
     }
 
     pub(super) fn deallocate_local(
diff --git a/src/librustc_mir/interpret/intrinsics.rs b/src/librustc_mir/interpret/intrinsics.rs
index d8778dfeef7a1..e002c3fd511d6 100644
--- a/src/librustc_mir/interpret/intrinsics.rs
+++ b/src/librustc_mir/interpret/intrinsics.rs
@@ -1,10 +1,10 @@
 //! Intrinsics and other functions that the miri engine executes without
-//! looking at their MIR.  Intrinsics/functions supported here are shared by CTFE
+//! looking at their MIR. Intrinsics/functions supported here are shared by CTFE
 //! and miri.
 
 use syntax::symbol::Symbol;
 use rustc::ty;
-use rustc::ty::layout::{LayoutOf, Primitive};
+use rustc::ty::layout::{LayoutOf, Primitive, Size};
 use rustc::mir::BinOp;
 use rustc::mir::interpret::{
     EvalResult, EvalErrorKind, Scalar,
@@ -37,7 +37,7 @@ fn numeric_intrinsic<'tcx, Tag>(
 }
 
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
-    /// Returns whether emulation happened.
+    /// Returns `true` if emulation happened.
     pub fn emulate_intrinsic(
         &mut self,
         instance: ty::Instance<'tcx>,
@@ -122,6 +122,49 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     self.binop_with_overflow(bin_op, lhs, rhs, dest)?;
                 }
             }
+            "saturating_add" | "saturating_sub" => {
+                let l = self.read_immediate(args[0])?;
+                let r = self.read_immediate(args[1])?;
+                let is_add = intrinsic_name == "saturating_add";
+                let (val, overflowed) = self.binary_op(if is_add {
+                    BinOp::Add
+                } else {
+                    BinOp::Sub
+                }, l, r)?;
+                let val = if overflowed {
+                    let num_bits = l.layout.size.bits();
+                    if l.layout.abi.is_signed() {
+                        // For signed ints the saturated value depends on the sign of the first
+                        // term since the sign of the second term can be inferred from this and
+                        // the fact that the operation has overflowed (if either is 0 no
+                        // overflow can occur)
+                        let first_term: u128 = l.to_scalar()?.to_bits(l.layout.size)?;
+                        let first_term_positive = first_term & (1 << (num_bits-1)) == 0;
+                        if first_term_positive {
+                            // Negative overflow not possible since the positive first term
+                            // can only increase an (in range) negative term for addition
+                            // or corresponding negated positive term for subtraction
+                            Scalar::from_uint((1u128 << (num_bits - 1)) - 1,  // max positive
+                                Size::from_bits(num_bits))
+                        } else {
+                            // Positive overflow not possible for similar reason
+                            // max negative
+                            Scalar::from_uint(1u128 << (num_bits - 1), Size::from_bits(num_bits))
+                        }
+                    } else {  // unsigned
+                        if is_add {
+                            // max unsigned
+                            Scalar::from_uint(u128::max_value() >> (128 - num_bits),
+                                Size::from_bits(num_bits))
+                        } else {  // underflow to 0
+                            Scalar::from_uint(0u128, Size::from_bits(num_bits))
+                        }
+                    }
+                } else {
+                    val
+                };
+                self.write_scalar(val, dest)?;
+            }
             "unchecked_shl" | "unchecked_shr" => {
                 let l = self.read_immediate(args[0])?;
                 let r = self.read_immediate(args[1])?;
@@ -130,7 +173,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     "unchecked_shr" => BinOp::Shr,
                     _ => bug!("Already checked for int ops")
                 };
-                let (val, overflowed) = self.binary_op_imm(bin_op, l, r)?;
+                let (val, overflowed) = self.binary_op(bin_op, l, r)?;
                 if overflowed {
                     let layout = self.layout_of(substs.type_at(0))?;
                     let r_val =  r.to_scalar()?.to_bits(layout.size)?;
@@ -169,7 +212,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     }
 
     /// "Intercept" a function call because we have something special to do for it.
-    /// Returns whether an intercept happened.
+    /// Returns `true` if an intercept happened.
     pub fn hook_fn(
         &mut self,
         instance: ty::Instance<'tcx>,
diff --git a/src/librustc_mir/interpret/machine.rs b/src/librustc_mir/interpret/machine.rs
index 26d526a6f5ff8..7fb4c47d92acb 100644
--- a/src/librustc_mir/interpret/machine.rs
+++ b/src/librustc_mir/interpret/machine.rs
@@ -7,11 +7,11 @@ use std::hash::Hash;
 
 use rustc::hir::{self, def_id::DefId};
 use rustc::mir;
-use rustc::ty::{self, layout::TyLayout, query::TyCtxtAt};
+use rustc::ty::{self, query::TyCtxtAt};
 
 use super::{
     Allocation, AllocId, EvalResult, Scalar, AllocationExtra,
-    EvalContext, PlaceTy, MPlaceTy, OpTy, Pointer, MemoryKind,
+    EvalContext, PlaceTy, MPlaceTy, OpTy, ImmTy, Pointer, MemoryKind,
 };
 
 /// Whether this kind of memory is allowed to leak
@@ -21,23 +21,23 @@ pub trait MayLeak: Copy {
 
 /// The functionality needed by memory to manage its allocations
 pub trait AllocMap<K: Hash + Eq, V> {
-    /// Test if the map contains the given key.
+    /// Tests if the map contains the given key.
     /// Deliberately takes `&mut` because that is sufficient, and some implementations
     /// can be more efficient then (using `RefCell::get_mut`).
     fn contains_key<Q: ?Sized + Hash + Eq>(&mut self, k: &Q) -> bool
         where K: Borrow<Q>;
 
-    /// Insert new entry into the map.
+    /// Inserts a new entry into the map.
     fn insert(&mut self, k: K, v: V) -> Option<V>;
 
-    /// Remove entry from the map.
+    /// Removes an entry from the map.
     fn remove<Q: ?Sized + Hash + Eq>(&mut self, k: &Q) -> Option<V>
         where K: Borrow<Q>;
 
-    /// Return data based the keys and values in the map.
+    /// Returns data based the keys and values in the map.
     fn filter_map_collect<T>(&self, f: impl FnMut(&K, &V) -> Option<T>) -> Vec<T>;
 
-    /// Return a reference to entry `k`.  If no such entry exists, call
+    /// Returns a reference to entry `k`. If no such entry exists, call
     /// `vacant` and either forward its error, or add its result to the map
     /// and return a reference to *that*.
     fn get_or<E>(
@@ -46,7 +46,7 @@ pub trait AllocMap<K: Hash + Eq, V> {
         vacant: impl FnOnce() -> Result<V, E>
     ) -> Result<&V, E>;
 
-    /// Return a mutable reference to entry `k`.  If no such entry exists, call
+    /// Returns a mutable reference to entry `k`. If no such entry exists, call
     /// `vacant` and either forward its error, or add its result to the map
     /// and return a reference to *that*.
     fn get_mut_or<E>(
@@ -62,7 +62,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     /// Additional memory kinds a machine wishes to distinguish from the builtin ones
     type MemoryKinds: ::std::fmt::Debug + MayLeak + Eq + 'static;
 
-    /// Tag tracked alongside every pointer.  This is used to implement "Stacked Borrows"
+    /// Tag tracked alongside every pointer. This is used to implement "Stacked Borrows"
     /// <https://www.ralfj.de/blog/2018/08/07/stacked-borrows.html>.
     /// The `default()` is used for pointers to consts, statics, vtables and functions.
     type PointerTag: ::std::fmt::Debug + Default + Copy + Eq + Hash + 'static;
@@ -70,7 +70,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     /// Extra data stored in every call frame.
     type FrameExtra;
 
-    /// Extra data stored in memory.  A reference to this is available when `AllocExtra`
+    /// Extra data stored in memory. A reference to this is available when `AllocExtra`
     /// gets initialized, so you can e.g., have an `Rc` here if there is global state you
     /// need access to in the `AllocExtra` hooks.
     type MemoryExtra: Default;
@@ -105,7 +105,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     ///
     /// Returns either the mir to use for the call, or `None` if execution should
     /// just proceed (which usually means this hook did all the work that the
-    /// called function should usually have done).  In the latter case, it is
+    /// called function should usually have done). In the latter case, it is
     /// this hook's responsibility to call `goto_block(ret)` to advance the instruction pointer!
     /// (This is to support functions like `__rust_maybe_catch_panic` that neither find a MIR
     /// nor just jump to `ret`, but instead push their own stack frame.)
@@ -158,10 +158,8 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     fn ptr_op(
         ecx: &EvalContext<'a, 'mir, 'tcx, Self>,
         bin_op: mir::BinOp,
-        left: Scalar<Self::PointerTag>,
-        left_layout: TyLayout<'tcx>,
-        right: Scalar<Self::PointerTag>,
-        right_layout: TyLayout<'tcx>,
+        left: ImmTy<'tcx, Self::PointerTag>,
+        right: ImmTy<'tcx, Self::PointerTag>,
     ) -> EvalResult<'tcx, (Scalar<Self::PointerTag>, bool)>;
 
     /// Heap allocations via the `box` keyword.
@@ -170,7 +168,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
         dest: PlaceTy<'tcx, Self::PointerTag>,
     ) -> EvalResult<'tcx>;
 
-    /// Add the tag for a newly allocated pointer.
+    /// Adds the tag for a newly allocated pointer.
     fn tag_new_allocation(
         ecx: &mut EvalContext<'a, 'mir, 'tcx, Self>,
         ptr: Pointer,
@@ -178,7 +176,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
     ) -> Pointer<Self::PointerTag>;
 
     /// Executed when evaluating the `*` operator: Following a reference.
-    /// This has the chance to adjust the tag.  It should not change anything else!
+    /// This has the chance to adjust the tag. It should not change anything else!
     /// `mutability` can be `None` in case a raw ptr is being dereferenced.
     #[inline]
     fn tag_dereference(
@@ -189,7 +187,7 @@ pub trait Machine<'a, 'mir, 'tcx>: Sized {
         Ok(place.ptr)
     }
 
-    /// Execute a retagging operation
+    /// Executes a retagging operation
     #[inline]
     fn retag(
         _ecx: &mut EvalContext<'a, 'mir, 'tcx, Self>,
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 3832d7e8d6245..88b936afaa4c1 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -3,7 +3,7 @@
 //! Generally, we use `Pointer` to denote memory addresses. However, some operations
 //! have a "size"-like parameter, and they take `Scalar` for the address because
 //! if the size is 0, then the pointer can also be a (properly aligned, non-NULL)
-//! integer.  It is crucial that these operations call `check_align` *before*
+//! integer. It is crucial that these operations call `check_align` *before*
 //! short-circuiting the empty case!
 
 use std::collections::VecDeque;
@@ -47,10 +47,10 @@ impl<T: MayLeak> MayLeak for MemoryKind<T> {
 // `Memory` has to depend on the `Machine` because some of its operations
 // (e.g., `get`) call a `Machine` hook.
 pub struct Memory<'a, 'mir, 'tcx: 'a + 'mir, M: Machine<'a, 'mir, 'tcx>> {
-    /// Allocations local to this instance of the miri engine.  The kind
+    /// Allocations local to this instance of the miri engine. The kind
     /// helps ensure that the same mechanism is used for allocation and
-    /// deallocation.  When an allocation is not found here, it is a
-    /// static and looked up in the `tcx` for read access.  Some machines may
+    /// deallocation. When an allocation is not found here, it is a
+    /// static and looked up in the `tcx` for read access. Some machines may
     /// have to mutate this map even on a read-only access to a static (because
     /// they do pointer provenance tracking and the allocations in `tcx` have
     /// the wrong type), so we let the machine override this type.
@@ -240,7 +240,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
         Ok(())
     }
 
-    /// Check that the pointer is aligned AND non-NULL. This supports ZSTs in two ways:
+    /// Checks that the pointer is aligned AND non-NULL. This supports ZSTs in two ways:
     /// You can pass a scalar, and a `Pointer` does not have to actually still be allocated.
     pub fn check_align(
         &self,
@@ -284,7 +284,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
         }
     }
 
-    /// Check if the pointer is "in-bounds". Notice that a pointer pointing at the end
+    /// Checks if the pointer is "in-bounds". Notice that a pointer pointing at the end
     /// of an allocation (i.e., at the first *inaccessible* location) *is* considered
     /// in-bounds!  This follows C's/LLVM's rules.
     /// If you want to check bounds before doing a memory access, better first obtain
@@ -659,7 +659,7 @@ where
     }
 }
 
-/// Reading and writing
+/// Reading and writing.
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
     pub fn copy(
         &mut self,
diff --git a/src/librustc_mir/interpret/mod.rs b/src/librustc_mir/interpret/mod.rs
index e3ab90a602040..d2ab3fcb7a30a 100644
--- a/src/librustc_mir/interpret/mod.rs
+++ b/src/librustc_mir/interpret/mod.rs
@@ -18,7 +18,7 @@ mod visitor;
 pub use rustc::mir::interpret::*; // have all the `interpret` symbols in one place: here
 
 pub use self::eval_context::{
-    EvalContext, Frame, StackPopCleanup, LocalValue,
+    EvalContext, Frame, StackPopCleanup, LocalState, LocalValue,
 };
 
 pub use self::place::{Place, PlaceTy, MemPlace, MPlaceTy};
diff --git a/src/librustc_mir/interpret/operand.rs b/src/librustc_mir/interpret/operand.rs
index 04e0955ad6172..c6902ddb3c6a6 100644
--- a/src/librustc_mir/interpret/operand.rs
+++ b/src/librustc_mir/interpret/operand.rs
@@ -10,8 +10,12 @@ use rustc::mir::interpret::{
     GlobalId, AllocId, InboundsCheck,
     ConstValue, Pointer, Scalar,
     EvalResult, EvalErrorKind,
+    sign_extend, truncate,
+};
+use super::{
+    EvalContext, Machine, AllocMap, Allocation, AllocationExtra,
+    MemPlace, MPlaceTy, PlaceTy, Place, MemoryKind,
 };
-use super::{EvalContext, Machine, MemPlace, MPlaceTy, MemoryKind};
 pub use rustc::mir::interpret::ScalarMaybeUndef;
 
 /// A `Value` represents a single immediate self-contained Rust value.
@@ -41,6 +45,11 @@ impl Immediate {
 }
 
 impl<'tcx, Tag> Immediate<Tag> {
+    #[inline]
+    pub fn from_scalar(val: Scalar<Tag>) -> Self {
+        Immediate::Scalar(ScalarMaybeUndef::Scalar(val))
+    }
+
     #[inline]
     pub fn erase_tag(self) -> Immediate
     {
@@ -87,7 +96,7 @@ impl<'tcx, Tag> Immediate<Tag> {
         }
     }
 
-    /// Convert the immediate into a pointer (or a pointer-sized integer).
+    /// Converts the immediate into a pointer (or a pointer-sized integer).
     /// Throws away the second half of a ScalarPair!
     #[inline]
     pub fn to_scalar_ptr(self) -> EvalResult<'tcx, Scalar<Tag>> {
@@ -97,7 +106,7 @@ impl<'tcx, Tag> Immediate<Tag> {
         }
     }
 
-    /// Convert the value into its metadata.
+    /// Converts the value into its metadata.
     /// Throws away the first half of a ScalarPair!
     #[inline]
     pub fn to_meta(self) -> EvalResult<'tcx, Option<Scalar<Tag>>> {
@@ -112,7 +121,7 @@ impl<'tcx, Tag> Immediate<Tag> {
 // as input for binary and cast operations.
 #[derive(Copy, Clone, Debug)]
 pub struct ImmTy<'tcx, Tag=()> {
-    immediate: Immediate<Tag>,
+    pub imm: Immediate<Tag>,
     pub layout: TyLayout<'tcx>,
 }
 
@@ -120,12 +129,12 @@ impl<'tcx, Tag> ::std::ops::Deref for ImmTy<'tcx, Tag> {
     type Target = Immediate<Tag>;
     #[inline(always)]
     fn deref(&self) -> &Immediate<Tag> {
-        &self.immediate
+        &self.imm
     }
 }
 
 /// An `Operand` is the result of computing a `mir::Operand`. It can be immediate,
-/// or still in memory.  The latter is an optimization, to delay reading that chunk of
+/// or still in memory. The latter is an optimization, to delay reading that chunk of
 /// memory and to avoid having to store arbitrary-sized data here.
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub enum Operand<Tag=(), Id=AllocId> {
@@ -180,7 +189,7 @@ impl<Tag> Operand<Tag> {
 
 #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
 pub struct OpTy<'tcx, Tag=()> {
-    crate op: Operand<Tag>, // ideally we'd make this private, but const_prop needs this
+    op: Operand<Tag>,
     pub layout: TyLayout<'tcx>,
 }
 
@@ -206,12 +215,25 @@ impl<'tcx, Tag> From<ImmTy<'tcx, Tag>> for OpTy<'tcx, Tag> {
     #[inline(always)]
     fn from(val: ImmTy<'tcx, Tag>) -> Self {
         OpTy {
-            op: Operand::Immediate(val.immediate),
+            op: Operand::Immediate(val.imm),
             layout: val.layout
         }
     }
 }
 
+impl<'tcx, Tag: Copy> ImmTy<'tcx, Tag>
+{
+    #[inline]
+    pub fn from_scalar(val: Scalar<Tag>, layout: TyLayout<'tcx>) -> Self {
+        ImmTy { imm: Immediate::from_scalar(val), layout }
+    }
+
+    #[inline]
+    pub fn to_bits(self) -> EvalResult<'tcx, u128> {
+        self.to_scalar()?.to_bits(self.layout.size)
+    }
+}
+
 impl<'tcx, Tag> OpTy<'tcx, Tag>
 {
     #[inline]
@@ -227,7 +249,7 @@ impl<'tcx, Tag> OpTy<'tcx, Tag>
 // Use the existing layout if given (but sanity check in debug mode),
 // or compute the layout.
 #[inline(always)]
-fn from_known_layout<'tcx>(
+pub(super) fn from_known_layout<'tcx>(
     layout: Option<TyLayout<'tcx>>,
     compute: impl FnOnce() -> EvalResult<'tcx, TyLayout<'tcx>>
 ) -> EvalResult<'tcx, TyLayout<'tcx>> {
@@ -247,7 +269,7 @@ fn from_known_layout<'tcx>(
 
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
     /// Try reading an immediate in memory; this is interesting particularly for ScalarPair.
-    /// Return None if the layout does not permit loading this as a value.
+    /// Returns `None` if the layout does not permit loading this as a value.
     pub(super) fn try_read_immediate_from_mplace(
         &self,
         mplace: MPlaceTy<'tcx, M::PointerTag>,
@@ -324,8 +346,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         &self,
         op: OpTy<'tcx, M::PointerTag>
     ) -> EvalResult<'tcx, ImmTy<'tcx, M::PointerTag>> {
-        if let Ok(immediate) = self.try_read_immediate(op)? {
-            Ok(ImmTy { immediate, layout: op.layout })
+        if let Ok(imm) = self.try_read_immediate(op)? {
+            Ok(ImmTy { imm, layout: op.layout })
         } else {
             bug!("primitive read failed for type: {:?}", op.layout.ty);
         }
@@ -457,8 +479,6 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     }
 
     /// This is used by [priroda](https://github.com/oli-obk/priroda) to get an OpTy from a local
-    ///
-    /// When you know the layout of the local in advance, you can pass it as last argument
     pub fn access_local(
         &self,
         frame: &super::Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
@@ -467,14 +487,28 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>> {
         assert_ne!(local, mir::RETURN_PLACE);
         let op = *frame.locals[local].access()?;
-        let layout = from_known_layout(layout,
-                    || self.layout_of_local(frame, local))?;
+        let layout = self.layout_of_local(frame, local, layout)?;
         Ok(OpTy { op, layout })
     }
 
+    /// Every place can be read from, so we can turm them into an operand
+    #[inline(always)]
+    pub fn place_to_op(
+        &self,
+        place: PlaceTy<'tcx, M::PointerTag>
+    ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>> {
+        let op = match *place {
+            Place::Ptr(mplace) => {
+                Operand::Indirect(mplace)
+            }
+            Place::Local { frame, local } =>
+                *self.stack[frame].locals[local].access()?
+        };
+        Ok(OpTy { op, layout: place.layout })
+    }
+
     // Evaluate a place with the goal of reading from it.  This lets us sometimes
-    // avoid allocations.  If you already know the layout, you can pass it in
-    // to avoid looking it up again.
+    // avoid allocations.
     fn eval_place_to_op(
         &self,
         mir_place: &mir::Place<'tcx>,
@@ -514,7 +548,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
 
             Constant(ref constant) => {
                 let layout = from_known_layout(layout, || {
-                    let ty = self.monomorphize(mir_op.ty(self.mir(), *self.tcx), self.substs());
+                    let ty = self.monomorphize(mir_op.ty(self.mir(), *self.tcx))?;
                     self.layout_of(ty)
                 })?;
                 let op = self.const_value_to_op(*constant.literal)?;
@@ -535,10 +569,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             .collect()
     }
 
-    // Used when miri runs into a constant, and by CTFE.
-    // FIXME: CTFE should use allocations, then we can make this private (embed it into
-    // `eval_operand`, ideally).
-    pub(crate) fn const_value_to_op(
+    // Used when Miri runs into a constant, and (indirectly through lazy_const_to_op) by CTFE.
+    fn const_value_to_op(
         &self,
         val: ty::LazyConst<'tcx>,
     ) -> EvalResult<'tcx, Operand<M::PointerTag>> {
@@ -561,10 +593,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     MemPlace::from_ptr(Pointer::new(id, offset), alloc.align)
                 ).with_default_tag())
             },
-            ConstValue::ScalarPair(a, b) =>
+            ConstValue::Slice(a, b) =>
                 Ok(Operand::Immediate(Immediate::ScalarPair(
                     a.into(),
-                    b.into(),
+                    Scalar::from_uint(b, self.tcx.data_layout.pointer_size).into(),
                 )).with_default_tag()),
             ConstValue::Scalar(x) =>
                 Ok(Operand::Immediate(Immediate::Scalar(x.into())).with_default_tag()),
@@ -602,20 +634,17 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     Err(_) => return err!(InvalidDiscriminant(raw_discr.erase_tag())),
                 };
                 let real_discr = if discr_val.layout.ty.is_signed() {
-                    let i = bits_discr as i128;
                     // going from layout tag type to typeck discriminant type
                     // requires first sign extending with the layout discriminant
-                    let shift = 128 - discr_val.layout.size.bits();
-                    let sexted = (i << shift) >> shift;
+                    let sexted = sign_extend(bits_discr, discr_val.layout.size) as i128;
                     // and then zeroing with the typeck discriminant type
                     let discr_ty = rval.layout.ty
                         .ty_adt_def().expect("tagged layout corresponds to adt")
                         .repr
                         .discr_type();
-                    let discr_ty = layout::Integer::from_attr(self, discr_ty);
-                    let shift = 128 - discr_ty.size().bits();
+                    let size = layout::Integer::from_attr(self, discr_ty).size();
                     let truncatee = sexted as u128;
-                    (truncatee << shift) >> shift
+                    truncate(truncatee, size)
                 } else {
                     bits_discr
                 };
@@ -670,3 +699,21 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     }
 
 }
+
+impl<'a, 'mir, 'tcx, M> EvalContext<'a, 'mir, 'tcx, M>
+where
+    M: Machine<'a, 'mir, 'tcx, PointerTag=()>,
+    // FIXME: Working around https://github.com/rust-lang/rust/issues/24159
+    M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation<(), M::AllocExtra>)>,
+    M::AllocExtra: AllocationExtra<(), M::MemoryExtra>,
+{
+    // FIXME: CTFE should use allocations, then we can remove this.
+    pub(crate) fn lazy_const_to_op(
+        &self,
+        cnst: ty::LazyConst<'tcx>,
+        ty: ty::Ty<'tcx>,
+    ) -> EvalResult<'tcx, OpTy<'tcx>> {
+        let op = self.const_value_to_op(cnst)?;
+        Ok(OpTy { op, layout: self.layout_of(ty)? })
+    }
+}
diff --git a/src/librustc_mir/interpret/operator.rs b/src/librustc_mir/interpret/operator.rs
index 5e3335f4c7219..b3b9c742d6c28 100644
--- a/src/librustc_mir/interpret/operator.rs
+++ b/src/librustc_mir/interpret/operator.rs
@@ -18,7 +18,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         right: ImmTy<'tcx, M::PointerTag>,
         dest: PlaceTy<'tcx, M::PointerTag>,
     ) -> EvalResult<'tcx> {
-        let (val, overflowed) = self.binary_op_imm(op, left, right)?;
+        let (val, overflowed) = self.binary_op(op, left, right)?;
         let val = Immediate::ScalarPair(val.into(), Scalar::from_bool(overflowed).into());
         self.write_immediate(val, dest)
     }
@@ -32,7 +32,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         right: ImmTy<'tcx, M::PointerTag>,
         dest: PlaceTy<'tcx, M::PointerTag>,
     ) -> EvalResult<'tcx> {
-        let (val, _overflowed) = self.binary_op_imm(op, left, right)?;
+        let (val, _overflowed) = self.binary_op(op, left, right)?;
         self.write_scalar(val, dest)
     }
 }
@@ -272,69 +272,55 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         Ok((val, false))
     }
 
-    /// Convenience wrapper that's useful when keeping the layout together with the
-    /// immediate value.
+    /// Returns the result of the specified operation and whether it overflowed.
     #[inline]
-    pub fn binary_op_imm(
+    pub fn binary_op(
         &self,
         bin_op: mir::BinOp,
         left: ImmTy<'tcx, M::PointerTag>,
         right: ImmTy<'tcx, M::PointerTag>,
-    ) -> EvalResult<'tcx, (Scalar<M::PointerTag>, bool)> {
-        self.binary_op(
-            bin_op,
-            left.to_scalar()?, left.layout,
-            right.to_scalar()?, right.layout,
-        )
-    }
-
-    /// Returns the result of the specified operation and whether it overflowed.
-    pub fn binary_op(
-        &self,
-        bin_op: mir::BinOp,
-        left: Scalar<M::PointerTag>,
-        left_layout: TyLayout<'tcx>,
-        right: Scalar<M::PointerTag>,
-        right_layout: TyLayout<'tcx>,
     ) -> EvalResult<'tcx, (Scalar<M::PointerTag>, bool)> {
         trace!("Running binary op {:?}: {:?} ({:?}), {:?} ({:?})",
-            bin_op, left, left_layout.ty, right, right_layout.ty);
+            bin_op, *left, left.layout.ty, *right, right.layout.ty);
 
-        match left_layout.ty.sty {
+        match left.layout.ty.sty {
             ty::Char => {
-                assert_eq!(left_layout.ty, right_layout.ty);
-                let left = left.to_char()?;
-                let right = right.to_char()?;
+                assert_eq!(left.layout.ty, right.layout.ty);
+                let left = left.to_scalar()?.to_char()?;
+                let right = right.to_scalar()?.to_char()?;
                 self.binary_char_op(bin_op, left, right)
             }
             ty::Bool => {
-                assert_eq!(left_layout.ty, right_layout.ty);
-                let left = left.to_bool()?;
-                let right = right.to_bool()?;
+                assert_eq!(left.layout.ty, right.layout.ty);
+                let left = left.to_scalar()?.to_bool()?;
+                let right = right.to_scalar()?.to_bool()?;
                 self.binary_bool_op(bin_op, left, right)
             }
             ty::Float(fty) => {
-                assert_eq!(left_layout.ty, right_layout.ty);
-                let left = left.to_bits(left_layout.size)?;
-                let right = right.to_bits(right_layout.size)?;
+                assert_eq!(left.layout.ty, right.layout.ty);
+                let left = left.to_bits()?;
+                let right = right.to_bits()?;
                 self.binary_float_op(bin_op, fty, left, right)
             }
             _ => {
                 // Must be integer(-like) types.  Don't forget about == on fn pointers.
-                assert!(left_layout.ty.is_integral() || left_layout.ty.is_unsafe_ptr() ||
-                    left_layout.ty.is_fn());
-                assert!(right_layout.ty.is_integral() || right_layout.ty.is_unsafe_ptr() ||
-                    right_layout.ty.is_fn());
+                assert!(left.layout.ty.is_integral() || left.layout.ty.is_unsafe_ptr() ||
+                    left.layout.ty.is_fn());
+                assert!(right.layout.ty.is_integral() || right.layout.ty.is_unsafe_ptr() ||
+                    right.layout.ty.is_fn());
 
                 // Handle operations that support pointer values
-                if left.is_ptr() || right.is_ptr() || bin_op == mir::BinOp::Offset {
-                    return M::ptr_op(self, bin_op, left, left_layout, right, right_layout);
+                if left.to_scalar_ptr()?.is_ptr() ||
+                    right.to_scalar_ptr()?.is_ptr() ||
+                    bin_op == mir::BinOp::Offset
+                {
+                    return M::ptr_op(self, bin_op, left, right);
                 }
 
                 // Everything else only works with "proper" bits
-                let left = left.to_bits(left_layout.size).expect("we checked is_ptr");
-                let right = right.to_bits(right_layout.size).expect("we checked is_ptr");
-                self.binary_int_op(bin_op, left, left_layout, right, right_layout)
+                let l = left.to_bits().expect("we checked is_ptr");
+                let r = right.to_bits().expect("we checked is_ptr");
+                self.binary_int_op(bin_op, l, left.layout, r, right.layout)
             }
         }
     }
@@ -342,13 +328,14 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
     pub fn unary_op(
         &self,
         un_op: mir::UnOp,
-        val: Scalar<M::PointerTag>,
-        layout: TyLayout<'tcx>,
+        val: ImmTy<'tcx, M::PointerTag>,
     ) -> EvalResult<'tcx, Scalar<M::PointerTag>> {
         use rustc::mir::UnOp::*;
         use rustc_apfloat::ieee::{Single, Double};
         use rustc_apfloat::Float;
 
+        let layout = val.layout;
+        let val = val.to_scalar()?;
         trace!("Running unary op {:?}: {:?} ({:?})", un_op, val, layout.ty.sty);
 
         match layout.ty.sty {
diff --git a/src/librustc_mir/interpret/place.rs b/src/librustc_mir/interpret/place.rs
index 962e0b7a74201..ec701a939f225 100644
--- a/src/librustc_mir/interpret/place.rs
+++ b/src/librustc_mir/interpret/place.rs
@@ -9,6 +9,7 @@ use rustc::hir;
 use rustc::mir;
 use rustc::ty::{self, Ty};
 use rustc::ty::layout::{self, Size, Align, LayoutOf, TyLayout, HasDataLayout, VariantIdx};
+use rustc::ty::TypeFoldable;
 
 use super::{
     GlobalId, AllocId, Allocation, Scalar, EvalResult, Pointer, PointerArithmetic,
@@ -23,7 +24,7 @@ pub struct MemPlace<Tag=(), Id=AllocId> {
     /// However, it may never be undef.
     pub ptr: Scalar<Tag, Id>,
     pub align: Align,
-    /// Metadata for unsized places.  Interpretation is up to the type.
+    /// Metadata for unsized places. Interpretation is up to the type.
     /// Must not be present for sized types, but can be missing for unsized types
     /// (e.g., `extern type`).
     pub meta: Option<Scalar<Tag, Id>>,
@@ -243,10 +244,10 @@ impl<'tcx, Tag> MPlaceTy<'tcx, Tag> {
     }
 }
 
-impl<'tcx, Tag: ::std::fmt::Debug> OpTy<'tcx, Tag> {
+impl<'tcx, Tag: ::std::fmt::Debug + Copy> OpTy<'tcx, Tag> {
     #[inline(always)]
     pub fn try_as_mplace(self) -> Result<MPlaceTy<'tcx, Tag>, Immediate<Tag>> {
-        match self.op {
+        match *self {
             Operand::Indirect(mplace) => Ok(MPlaceTy { mplace, layout: self.layout }),
             Operand::Immediate(imm) => Err(imm),
         }
@@ -325,6 +326,10 @@ where
 
         let mplace = MemPlace {
             ptr: val.to_scalar_ptr()?,
+            // We could use the run-time alignment here. For now, we do not, because
+            // the point of tracking the alignment here is to make sure that the *static*
+            // alignment information emitted with the loads is correct. The run-time
+            // alignment can only be more restrictive.
             align: layout.align.abi,
             meta: val.to_meta()?,
         };
@@ -384,9 +389,11 @@ where
         // above). In that case, all fields are equal.
         let field_layout = base.layout.field(self, usize::try_from(field).unwrap_or(0))?;
 
-        // Offset may need adjustment for unsized fields
+        // Offset may need adjustment for unsized fields.
         let (meta, offset) = if field_layout.is_unsized() {
-            // re-use parent metadata to determine dynamic field layout
+            // Re-use parent metadata to determine dynamic field layout.
+            // With custom DSTS, this *will* execute user-defined code, but the same
+            // happens at run-time so that's okay.
             let align = match self.size_and_align_of(base.meta, field_layout)? {
                 Some((_, align)) => align,
                 None if offset == Size::ZERO =>
@@ -486,9 +493,9 @@ where
             Deref => self.deref_operand(base.into())?,
 
             Index(local) => {
-                let n = *self.frame().locals[local].access()?;
-                let n_layout = self.layout_of(self.tcx.types.usize)?;
-                let n = self.read_scalar(OpTy { op: n, layout: n_layout })?;
+                let layout = self.layout_of(self.tcx.types.usize)?;
+                let n = self.access_local(self.frame(), local, Some(layout))?;
+                let n = self.read_scalar(n)?;
                 let n = n.to_bits(self.tcx.data_layout.pointer_size)?;
                 self.mplace_field(base, u64::try_from(n).unwrap())?
             }
@@ -515,7 +522,7 @@ where
         })
     }
 
-    /// Get the place of a field inside the place, and also the field's type.
+    /// Gets the place of a field inside the place, and also the field's type.
     /// Just a convenience function, but used quite a bit.
     /// This is the only projection that might have a side-effect: We cannot project
     /// into the field of a local `ScalarPair`, we have to first allocate it.
@@ -546,7 +553,7 @@ where
         })
     }
 
-    /// Project into a place
+    /// Projects into a place.
     pub fn place_projection(
         &mut self,
         base: PlaceTy<'tcx, M::PointerTag>,
@@ -566,7 +573,7 @@ where
         })
     }
 
-    /// Evaluate statics and promoteds to an `MPlace`.  Used to share some code between
+    /// Evaluate statics and promoteds to an `MPlace`. Used to share some code between
     /// `eval_place` and `eval_place_to_op`.
     pub(super) fn eval_place_to_mplace(
         &self,
@@ -583,8 +590,8 @@ where
             }
 
             Static(ref static_) => {
-                let ty = self.monomorphize(static_.ty, self.substs());
-                let layout = self.layout_of(ty)?;
+                assert!(!static_.ty.needs_subst());
+                let layout = self.layout_of(static_.ty)?;
                 let instance = ty::Instance::mono(*self.tcx, static_.def_id);
                 let cid = GlobalId {
                     instance,
@@ -609,7 +616,7 @@ where
         })
     }
 
-    /// Compute a place.  You should only use this if you intend to write into this
+    /// Computes a place. You should only use this if you intend to write into this
     /// place; for reading, a more efficient alternative is `eval_place_for_read`.
     pub fn eval_place(
         &mut self,
@@ -623,7 +630,7 @@ where
                     // their layout on return.
                     PlaceTy {
                         place: *return_place,
-                        layout: self.layout_of_local(self.frame(), mir::RETURN_PLACE)?,
+                        layout: self.layout_of(self.monomorphize(self.frame().mir.return_ty())?)?,
                     },
                 None => return err!(InvalidNullPointerUsage),
             },
@@ -632,7 +639,7 @@ where
                     frame: self.cur_frame(),
                     local,
                 },
-                layout: self.layout_of_local(self.frame(), local)?,
+                layout: self.layout_of_local(self.frame(), local, None)?,
             },
 
             Projection(ref proj) => {
@@ -784,7 +791,7 @@ where
         }
     }
 
-    /// Copy the data from an operand to a place.  This does not support transmuting!
+    /// Copies the data from an operand to a place. This does not support transmuting!
     /// Use `copy_op_transmute` if the layouts could disagree.
     #[inline(always)]
     pub fn copy_op(
@@ -802,7 +809,7 @@ where
         Ok(())
     }
 
-    /// Copy the data from an operand to a place.  This does not support transmuting!
+    /// Copies the data from an operand to a place. This does not support transmuting!
     /// Use `copy_op_transmute` if the layouts could disagree.
     /// Also, if you use this you are responsible for validating that things git copied at the
     /// right type.
@@ -822,6 +829,8 @@ where
         let src = match self.try_read_immediate(src)? {
             Ok(src_val) => {
                 // Yay, we got a value that we can write directly.
+                // FIXME: Add a check to make sure that if `src` is indirect,
+                // it does not overlap with `dest`.
                 return self.write_immediate_no_validate(src_val, dest);
             }
             Err(mplace) => mplace,
@@ -835,13 +844,14 @@ where
         self.memory.copy(
             src_ptr, src_align,
             dest_ptr, dest_align,
-            dest.layout.size, false
+            dest.layout.size,
+            /*nonoverlapping*/ true,
         )?;
 
         Ok(())
     }
 
-    /// Copy the data from an operand to a place.  The layouts may disagree, but they must
+    /// Copies the data from an operand to a place. The layouts may disagree, but they must
     /// have the same size.
     pub fn copy_op_transmute(
         &mut self,
@@ -880,7 +890,7 @@ where
         Ok(())
     }
 
-    /// Make sure that a place is in memory, and return where it is.
+    /// Ensures that a place is in memory, and returns where it is.
     /// If the place currently refers to a local that doesn't yet have a matching allocation,
     /// create such an allocation.
     /// This is essentially `force_to_memplace`.
@@ -900,7 +910,7 @@ where
                         // We need the layout of the local.  We can NOT use the layout we got,
                         // that might e.g., be an inner field of a struct with `Scalar` layout,
                         // that has different alignment than the outer field.
-                        let local_layout = self.layout_of_local(&self.stack[frame], local)?;
+                        let local_layout = self.layout_of_local(&self.stack[frame], local, None)?;
                         let ptr = self.allocate(local_layout, MemoryKind::Stack);
                         // We don't have to validate as we can assume the local
                         // was already valid for its type.
@@ -987,22 +997,6 @@ where
         Ok(())
     }
 
-    /// Every place can be read from, so we can turm them into an operand
-    #[inline(always)]
-    pub fn place_to_op(
-        &self,
-        place: PlaceTy<'tcx, M::PointerTag>
-    ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>> {
-        let op = match place.place {
-            Place::Ptr(mplace) => {
-                Operand::Indirect(mplace)
-            }
-            Place::Local { frame, local } =>
-                *self.stack[frame].locals[local].access()?
-        };
-        Ok(OpTy { op, layout: place.layout })
-    }
-
     pub fn raw_const_to_mplace(
         &self,
         raw: RawConst<'tcx>,
diff --git a/src/librustc_mir/interpret/snapshot.rs b/src/librustc_mir/interpret/snapshot.rs
index f9ce7b4319fac..0168e1301fa7a 100644
--- a/src/librustc_mir/interpret/snapshot.rs
+++ b/src/librustc_mir/interpret/snapshot.rs
@@ -23,9 +23,9 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use syntax::ast::Mutability;
 use syntax::source_map::Span;
 
-use super::eval_context::{LocalValue, StackPopCleanup};
-use super::{Frame, Memory, Operand, MemPlace, Place, Immediate, ScalarMaybeUndef};
-use const_eval::CompileTimeInterpreter;
+use super::eval_context::{LocalState, StackPopCleanup};
+use super::{Frame, Memory, Operand, MemPlace, Place, Immediate, ScalarMaybeUndef, LocalValue};
+use crate::const_eval::CompileTimeInterpreter;
 
 #[derive(Default)]
 pub(crate) struct InfiniteLoopDetector<'a, 'mir, 'tcx: 'a + 'mir> {
@@ -101,9 +101,8 @@ macro_rules! __impl_snapshot_field {
 // This assumes the type has two type parameters, first for the tag (set to `()`),
 // then for the id
 macro_rules! impl_snapshot_for {
-    // FIXME(mark-i-m): Some of these should be `?` rather than `*`.
     (enum $enum_name:ident {
-        $( $variant:ident $( ( $($field:ident $(-> $delegate:expr)*),* ) )* ),* $(,)*
+        $( $variant:ident $( ( $($field:ident $(-> $delegate:expr)?),* ) )? ),* $(,)?
     }) => {
 
         impl<'a, Ctx> self::Snapshot<'a, Ctx> for $enum_name
@@ -115,18 +114,17 @@ macro_rules! impl_snapshot_for {
             fn snapshot(&self, __ctx: &'a Ctx) -> Self::Item {
                 match *self {
                     $(
-                        $enum_name::$variant $( ( $(ref $field),* ) )* =>
+                        $enum_name::$variant $( ( $(ref $field),* ) )? =>
                             $enum_name::$variant $(
-                                ( $( __impl_snapshot_field!($field, __ctx $(, $delegate)*) ),* ),
-                            )*
+                                ( $( __impl_snapshot_field!($field, __ctx $(, $delegate)?) ),* ),
+                            )?
                     )*
                 }
             }
         }
     };
 
-    // FIXME(mark-i-m): same here.
-    (struct $struct_name:ident { $($field:ident $(-> $delegate:expr)*),*  $(,)* }) => {
+    (struct $struct_name:ident { $($field:ident $(-> $delegate:expr)?),*  $(,)? }) => {
         impl<'a, Ctx> self::Snapshot<'a, Ctx> for $struct_name
             where Ctx: self::SnapshotContext<'a>,
         {
@@ -139,7 +137,7 @@ macro_rules! impl_snapshot_for {
                 } = *self;
 
                 $struct_name {
-                    $( $field: __impl_snapshot_field!($field, __ctx $(, $delegate)*) ),*
+                    $( $field: __impl_snapshot_field!($field, __ctx $(, $delegate)?) ),*
                 }
             }
         }
@@ -200,7 +198,7 @@ impl_snapshot_for!(enum ScalarMaybeUndef {
     Undef,
 });
 
-impl_stable_hash_for!(struct ::interpret::MemPlace {
+impl_stable_hash_for!(struct crate::interpret::MemPlace {
     ptr,
     align,
     meta,
@@ -211,7 +209,7 @@ impl_snapshot_for!(struct MemPlace {
     align -> *align, // just copy alignment verbatim
 });
 
-impl_stable_hash_for!(enum ::interpret::Place {
+impl_stable_hash_for!(enum crate::interpret::Place {
     Ptr(mem_place),
     Local { frame, local },
 });
@@ -232,7 +230,7 @@ impl<'a, Ctx> Snapshot<'a, Ctx> for Place
     }
 }
 
-impl_stable_hash_for!(enum ::interpret::Immediate {
+impl_stable_hash_for!(enum crate::interpret::Immediate {
     Scalar(x),
     ScalarPair(x, y),
 });
@@ -241,7 +239,7 @@ impl_snapshot_for!(enum Immediate {
     ScalarPair(s, t),
 });
 
-impl_stable_hash_for!(enum ::interpret::Operand {
+impl_stable_hash_for!(enum crate::interpret::Operand {
     Immediate(x),
     Indirect(x),
 });
@@ -250,7 +248,7 @@ impl_snapshot_for!(enum Operand {
     Indirect(m),
 });
 
-impl_stable_hash_for!(enum ::interpret::LocalValue {
+impl_stable_hash_for!(enum crate::interpret::LocalValue {
     Dead,
     Live(x),
 });
@@ -298,7 +296,7 @@ impl<'a, Ctx> Snapshot<'a, Ctx> for &'a Allocation
     }
 }
 
-impl_stable_hash_for!(enum ::interpret::eval_context::StackPopCleanup {
+impl_stable_hash_for!(enum crate::interpret::eval_context::StackPopCleanup {
     Goto(block),
     None { cleanup },
 });
@@ -314,7 +312,7 @@ struct FrameSnapshot<'a, 'tcx: 'a> {
     stmt: usize,
 }
 
-impl_stable_hash_for!(impl<'tcx, 'mir: 'tcx> for struct Frame<'mir, 'tcx> {
+impl_stable_hash_for!(impl<'mir, 'tcx: 'mir> for struct Frame<'mir, 'tcx> {
     mir,
     instance,
     span,
@@ -356,6 +354,22 @@ impl<'a, 'mir, 'tcx, Ctx> Snapshot<'a, Ctx> for &'a Frame<'mir, 'tcx>
     }
 }
 
+impl<'a, 'tcx, Ctx> Snapshot<'a, Ctx> for &'a LocalState<'tcx>
+    where Ctx: SnapshotContext<'a>,
+{
+    type Item = LocalValue<(), AllocIdSnapshot<'a>>;
+
+    fn snapshot(&self, ctx: &'a Ctx) -> Self::Item {
+        let LocalState { state, layout: _ } = self;
+        state.snapshot(ctx)
+    }
+}
+
+impl_stable_hash_for!(struct LocalState<'tcx> {
+    state,
+    layout -> _,
+});
+
 impl<'a, 'b, 'mir, 'tcx: 'a+'mir> SnapshotContext<'b>
     for Memory<'a, 'mir, 'tcx, CompileTimeInterpreter<'a, 'mir, 'tcx>>
 {
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index 2de8b3c1afdf3..97ef2b5fa3485 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -41,7 +41,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         Ok(())
     }
 
-    /// Returns true as long as there are more things to do.
+    /// Returns `true` as long as there are more things to do.
     ///
     /// This is used by [priroda](https://github.com/oli-obk/priroda)
     pub fn step(&mut self) -> EvalResult<'tcx, bool> {
@@ -176,7 +176,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             UnaryOp(un_op, ref operand) => {
                 // The operand always has the same type as the result.
                 let val = self.read_immediate(self.eval_operand(operand, Some(dest.layout))?)?;
-                let val = self.unary_op(un_op, val.to_scalar()?, dest.layout)?;
+                let val = self.unary_op(un_op, val)?;
                 self.write_scalar(val, dest)?;
             }
 
@@ -248,7 +248,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             }
 
             NullaryOp(mir::NullOp::SizeOf, ty) => {
-                let ty = self.monomorphize(ty, self.substs());
+                let ty = self.monomorphize(ty)?;
                 let layout = self.layout_of(ty)?;
                 assert!(!layout.is_unsized(),
                         "SizeOf nullary MIR operator called for unsized type");
@@ -260,7 +260,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             }
 
             Cast(kind, ref operand, cast_ty) => {
-                debug_assert_eq!(self.monomorphize(cast_ty, self.substs()), dest.layout.ty);
+                debug_assert_eq!(self.monomorphize(cast_ty)?, dest.layout.ty);
                 let src = self.eval_operand(operand, None)?;
                 self.cast(src, kind, dest)?;
             }
diff --git a/src/librustc_mir/interpret/terminator.rs b/src/librustc_mir/interpret/terminator.rs
index 951e9fabe5932..c2ee3f5715bd3 100644
--- a/src/librustc_mir/interpret/terminator.rs
+++ b/src/librustc_mir/interpret/terminator.rs
@@ -7,7 +7,7 @@ use rustc_target::spec::abi::Abi;
 
 use rustc::mir::interpret::{EvalResult, PointerArithmetic, EvalErrorKind, Scalar};
 use super::{
-    EvalContext, Machine, Immediate, OpTy, PlaceTy, MPlaceTy, Operand, StackPopCleanup
+    EvalContext, Machine, Immediate, OpTy, ImmTy, PlaceTy, MPlaceTy, StackPopCleanup
 };
 
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
@@ -51,8 +51,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     // Compare using binary_op, to also support pointer values
                     let const_int = Scalar::from_uint(const_int, discr.layout.size);
                     let (res, _) = self.binary_op(mir::BinOp::Eq,
-                        discr.to_scalar()?, discr.layout,
-                        const_int, discr.layout,
+                        discr,
+                        ImmTy::from_scalar(const_int, discr.layout),
                     )?;
                     if res.to_bool()? {
                         target_block = targets[index];
@@ -112,7 +112,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                 let ty = place.layout.ty;
                 trace!("TerminatorKind::drop: {:?}, type {}", location, ty);
 
-                let instance = ::monomorphize::resolve_drop_in_place(*self.tcx, ty);
+                let instance = crate::monomorphize::resolve_drop_in_place(*self.tcx, ty);
                 self.drop_in_place(
                     place,
                     instance,
@@ -309,7 +309,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                         mir.spread_arg,
                         mir.args_iter()
                             .map(|local|
-                                (local, self.layout_of_local(self.frame(), local).unwrap().ty)
+                                (local, self.layout_of_local(self.frame(), local, None).unwrap().ty)
                             )
                             .collect::<Vec<_>>()
                     );
@@ -326,7 +326,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                     // last incoming argument.  These two iterators do not have the same type,
                     // so to keep the code paths uniform we accept an allocation
                     // (for RustCall ABI only).
-                    let caller_args : Cow<[OpTy<'tcx, M::PointerTag>]> =
+                    let caller_args : Cow<'_, [OpTy<'tcx, M::PointerTag>]> =
                         if caller_abi == Abi::RustCall && !args.is_empty() {
                             // Untuple
                             let (&untuple_arg, args) = args.split_last().unwrap();
@@ -335,7 +335,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                                 .chain((0..untuple_arg.layout.fields.count()).into_iter()
                                     .map(|i| self.operand_field(untuple_arg, i as u64))
                                 )
-                                .collect::<EvalResult<Vec<OpTy<'tcx, M::PointerTag>>>>()?)
+                                .collect::<EvalResult<'_, Vec<OpTy<'tcx, M::PointerTag>>>>()?)
                         } else {
                             // Plain arg passing
                             Cow::from(args)
@@ -383,7 +383,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                         }
                     } else {
                         let callee_layout =
-                            self.layout_of_local(self.frame(), mir::RETURN_PLACE)?;
+                            self.layout_of_local(self.frame(), mir::RETURN_PLACE, None)?;
                         if !callee_layout.abi.is_uninhabited() {
                             return err!(FunctionRetMismatch(
                                 self.tcx.types.never, callee_layout.ty
@@ -418,8 +418,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
                 let mut args = args.to_vec();
                 let pointee = args[0].layout.ty.builtin_deref(true).unwrap().ty;
                 let fake_fat_ptr_ty = self.tcx.mk_mut_ptr(pointee);
-                args[0].layout = self.layout_of(fake_fat_ptr_ty)?.field(self, 0)?;
-                args[0].op = Operand::Immediate(Immediate::Scalar(ptr.ptr.into())); // strip vtable
+                args[0] = OpTy::from(ImmTy { // strip vtable
+                    layout: self.layout_of(fake_fat_ptr_ty)?.field(self, 0)?,
+                    imm: Immediate::Scalar(ptr.ptr.into())
+                });
                 trace!("Patched self operand to {:#?}", args[0]);
                 // recurse with concrete function
                 self.eval_fn_call(instance, span, caller_abi, &args, dest, ret)
@@ -448,8 +450,8 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             _ => (instance, place),
         };
 
-        let arg = OpTy {
-            op: Operand::Immediate(place.to_ref()),
+        let arg = ImmTy {
+            imm: place.to_ref(),
             layout: self.layout_of(self.tcx.mk_mut_ptr(place.layout.ty))?,
         };
 
@@ -460,7 +462,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
             instance,
             span,
             Abi::Rust,
-            &[arg],
+            &[arg.into()],
             Some(dest.into()),
             Some(target),
         )
diff --git a/src/librustc_mir/interpret/traits.rs b/src/librustc_mir/interpret/traits.rs
index 642bbc114f562..1b0a9b17d3686 100644
--- a/src/librustc_mir/interpret/traits.rs
+++ b/src/librustc_mir/interpret/traits.rs
@@ -22,6 +22,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         let (ty, poly_trait_ref) = self.tcx.erase_regions(&(ty, poly_trait_ref));
 
         if let Some(&vtable) = self.vtables.get(&(ty, poly_trait_ref)) {
+            // This means we guarantee that there are no duplicate vtables, we will
+            // always use the same vtable for the same (Type, Trait) combination.
+            // That's not what happens in rustc, but emulating per-crate deduplication
+            // does not sound like it actually makes anything any better.
             return Ok(Pointer::from(vtable).with_default_tag());
         }
 
@@ -52,7 +56,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         ).with_default_tag();
         let tcx = &*self.tcx;
 
-        let drop = ::monomorphize::resolve_drop_in_place(*tcx, ty);
+        let drop = crate::monomorphize::resolve_drop_in_place(*tcx, ty);
         let drop = self.memory.create_fn_alloc(drop).with_default_tag();
         // no need to do any alignment checks on the memory accesses below, because we know the
         // allocation is correctly aligned as we created it above. Also we're only offsetting by
@@ -87,7 +91,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
         Ok(vtable)
     }
 
-    /// Return the drop fn instance as well as the actual dynamic type
+    /// Returns the drop fn instance as well as the actual dynamic type
     pub fn read_drop_type_from_vtable(
         &self,
         vtable: Pointer<M::PointerTag>,
diff --git a/src/librustc_mir/interpret/validity.rs b/src/librustc_mir/interpret/validity.rs
index a5fb44587400a..8b97d9ded7449 100644
--- a/src/librustc_mir/interpret/validity.rs
+++ b/src/librustc_mir/interpret/validity.rs
@@ -449,8 +449,13 @@ impl<'rt, 'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>>
         }
         // At least one value is excluded. Get the bits.
         let value = try_validation!(value.not_undef(),
-            value, self.path,
-            format!("something in the range {:?}", layout.valid_range));
+            value,
+            self.path,
+            format!(
+                "something {}",
+                wrapping_range_format(&layout.valid_range, max_hi),
+            )
+        );
         let bits = match value {
             Scalar::Ptr(ptr) => {
                 if lo == 1 && hi == max_hi {
@@ -582,7 +587,7 @@ impl<'rt, 'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>>
 }
 
 impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
-    /// This function checks the data at `op`.  `op` is assumed to cover valid memory if it
+    /// This function checks the data at `op`. `op` is assumed to cover valid memory if it
     /// is an indirect operand.
     /// It will error if the bits at the destination do not match the ones described by the layout.
     ///
diff --git a/src/librustc_mir/interpret/visitor.rs b/src/librustc_mir/interpret/visitor.rs
index 4773f5627d716..e2abf2ffc849c 100644
--- a/src/librustc_mir/interpret/visitor.rs
+++ b/src/librustc_mir/interpret/visitor.rs
@@ -16,26 +16,26 @@ use super::{
 // that's just more convenient to work with (avoids repeating all the `Machine` bounds).
 pub trait Value<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>>: Copy
 {
-    /// Get this value's layout.
+    /// Gets this value's layout.
     fn layout(&self) -> TyLayout<'tcx>;
 
-    /// Make this into an `OpTy`.
+    /// Makes this into an `OpTy`.
     fn to_op(
         self,
         ecx: &EvalContext<'a, 'mir, 'tcx, M>,
     ) -> EvalResult<'tcx, OpTy<'tcx, M::PointerTag>>;
 
-    /// Create this from an `MPlaceTy`.
-    fn from_mem_place(MPlaceTy<'tcx, M::PointerTag>) -> Self;
+    /// Creates this from an `MPlaceTy`.
+    fn from_mem_place(mplace: MPlaceTy<'tcx, M::PointerTag>) -> Self;
 
-    /// Project to the given enum variant.
+    /// Projects to the given enum variant.
     fn project_downcast(
         self,
         ecx: &EvalContext<'a, 'mir, 'tcx, M>,
         variant: VariantIdx,
     ) -> EvalResult<'tcx, Self>;
 
-    /// Project to the n-th field.
+    /// Projects to the n-th field.
     fn project_field(
         self,
         ecx: &EvalContext<'a, 'mir, 'tcx, M>,
@@ -125,29 +125,29 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Value<'a, 'mir, 'tcx, M>
 }
 
 macro_rules! make_value_visitor {
-    ($visitor_trait_name:ident, $($mutability:ident)*) => {
+    ($visitor_trait_name:ident, $($mutability:ident)?) => {
         // How to traverse a value and what to do when we are at the leaves.
         pub trait $visitor_trait_name<'a, 'mir, 'tcx: 'mir+'a, M: Machine<'a, 'mir, 'tcx>>: Sized {
             type V: Value<'a, 'mir, 'tcx, M>;
 
             /// The visitor must have an `EvalContext` in it.
-            fn ecx(&$($mutability)* self)
-                -> &$($mutability)* EvalContext<'a, 'mir, 'tcx, M>;
+            fn ecx(&$($mutability)? self)
+                -> &$($mutability)? EvalContext<'a, 'mir, 'tcx, M>;
 
             // Recursive actions, ready to be overloaded.
-            /// Visit the given value, dispatching as appropriate to more specialized visitors.
+            /// Visits the given value, dispatching as appropriate to more specialized visitors.
             #[inline(always)]
             fn visit_value(&mut self, v: Self::V) -> EvalResult<'tcx>
             {
                 self.walk_value(v)
             }
-            /// Visit the given value as a union.  No automatic recursion can happen here.
+            /// Visits the given value as a union. No automatic recursion can happen here.
             #[inline(always)]
             fn visit_union(&mut self, _v: Self::V) -> EvalResult<'tcx>
             {
                 Ok(())
             }
-            /// Visit this vale as an aggregate, you are even getting an iterator yielding
+            /// Visits this vale as an aggregate, you are even getting an iterator yielding
             /// all the fields (still in an `EvalResult`, you have to do error handling yourself).
             /// Recurses into the fields.
             #[inline(always)]
@@ -173,7 +173,7 @@ macro_rules! make_value_visitor {
                 self.visit_value(new_val)
             }
 
-            /// Called for recursing into the field of a generator.  These are not known to be
+            /// Called for recursing into the field of a generator. These are not known to be
             /// initialized, so we treat them like unions.
             #[inline(always)]
             fn visit_generator_field(
@@ -215,8 +215,8 @@ macro_rules! make_value_visitor {
             fn visit_scalar(&mut self, _v: Self::V, _layout: &layout::Scalar) -> EvalResult<'tcx>
             { Ok(()) }
 
-            /// Called whenever we reach a value of primitive type.  There can be no recursion
-            /// below such a value.  This is the leaf function.
+            /// Called whenever we reach a value of primitive type. There can be no recursion
+            /// below such a value. This is the leaf function.
             /// We do *not* provide an `ImmTy` here because some implementations might want
             /// to write to the place this primitive lives in.
             #[inline(always)]
diff --git a/src/librustc_mir/lib.rs b/src/librustc_mir/lib.rs
index 9395da60b3886..e0fee10cd008c 100644
--- a/src/librustc_mir/lib.rs
+++ b/src/librustc_mir/lib.rs
@@ -7,7 +7,6 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 #![feature(nll)]
 #![feature(in_band_lifetimes)]
 #![feature(slice_patterns)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(crate_visibility_modifier)]
@@ -24,43 +23,23 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 #![feature(unicode_internals)]
 #![feature(step_trait)]
 #![feature(slice_concat_ext)]
-#![cfg_attr(stage0, feature(if_while_or_patterns))]
 #![feature(try_from)]
 #![feature(reverse_bits)]
-#![cfg_attr(stage0, feature(underscore_imports))]
+#![feature(try_blocks)]
 
 #![recursion_limit="256"]
 
-extern crate arena;
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
 
-#[macro_use]
-extern crate bitflags;
 #[macro_use] extern crate log;
-extern crate either;
-extern crate graphviz as dot;
-extern crate polonius_engine;
 #[macro_use]
 extern crate rustc;
 #[macro_use] extern crate rustc_data_structures;
-extern crate serialize as rustc_serialize;
-extern crate rustc_errors;
+#[allow(unused_extern_crates)]
+extern crate serialize as rustc_serialize; // used by deriving
 #[macro_use]
 extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc_target;
-extern crate log_settings;
-extern crate rustc_apfloat;
-extern crate byteorder;
-extern crate core;
-extern crate smallvec;
-
-// Once we can use edition 2018 in the compiler,
-// replace this with real try blocks.
-macro_rules! try_block {
-    ($($inside:tt)*) => (
-        (||{ ::std::ops::Try::from_ok({ $($inside)* }) })()
-    )
-}
 
 mod diagnostics;
 
@@ -79,7 +58,7 @@ pub mod const_eval;
 pub use hair::pattern::check_crate as matchck_crate;
 use rustc::ty::query::Providers;
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     borrow_check::provide(providers);
     shim::provide(providers);
     transform::provide(providers);
diff --git a/src/librustc_mir/lints.rs b/src/librustc_mir/lints.rs
index 8ded31d89daea..6b6e8fcdc82cf 100644
--- a/src/librustc_mir/lints.rs
+++ b/src/librustc_mir/lints.rs
@@ -18,7 +18,7 @@ pub fn check(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 }
 
 fn check_fn_for_unconditional_recursion(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                                        fn_kind: FnKind,
+                                        fn_kind: FnKind<'_>,
                                         mir: &Mir<'tcx>,
                                         def_id: DefId) {
     if let FnKind::Closure(_) = fn_kind {
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index a6a8fe5ade56c..e68702bfe3ae0 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -177,23 +177,23 @@
 use rustc::hir::{self, CodegenFnAttrFlags};
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 
-use rustc::hir::def_id::DefId;
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::mir::interpret::{AllocId, ConstValue};
 use rustc::middle::lang_items::{ExchangeMallocFnLangItem, StartFnLangItem};
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, TypeFoldable, Ty, TyCtxt, GenericParamDefKind};
 use rustc::ty::adjustment::CustomCoerceUnsized;
-use rustc::session::config;
+use rustc::session::config::EntryFnType;
 use rustc::mir::{self, Location, Promoted};
 use rustc::mir::visit::Visitor as MirVisitor;
 use rustc::mir::mono::MonoItem;
 use rustc::mir::interpret::{Scalar, GlobalId, AllocKind, ErrorHandled};
 
-use monomorphize::{self, Instance};
+use crate::monomorphize::{self, Instance};
 use rustc::util::nodemap::{FxHashSet, FxHashMap, DefIdMap};
 use rustc::util::common::time;
 
-use monomorphize::item::{MonoItemExt, DefPathBasedNames, InstantiationMode};
+use crate::monomorphize::item::{MonoItemExt, DefPathBasedNames, InstantiationMode};
 
 use rustc_data_structures::bit_set::GrowableBitSet;
 use rustc_data_structures::sync::{MTRef, MTLock, ParallelIterator, par_iter};
@@ -321,9 +321,7 @@ fn collect_roots<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let mut roots = Vec::new();
 
     {
-        let entry_fn = tcx.sess.entry_fn.borrow().map(|(node_id, _, _)| {
-            tcx.hir().local_def_id(node_id)
-        });
+        let entry_fn = tcx.entry_fn(LOCAL_CRATE);
 
         debug!("collect_roots: entry_fn = {:?}", entry_fn);
 
@@ -357,7 +355,7 @@ fn collect_items_rec<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         // We've been here already, no need to search again.
         return;
     }
-    debug!("BEGIN collect_items_rec({})", starting_point.to_string(tcx));
+    debug!("BEGIN collect_items_rec({})", starting_point.to_string(tcx, true));
 
     let mut neighbors = Vec::new();
     let recursion_depth_reset;
@@ -411,7 +409,7 @@ fn collect_items_rec<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         recursion_depths.insert(def_id, depth);
     }
 
-    debug!("END collect_items_rec({})", starting_point.to_string(tcx));
+    debug!("END collect_items_rec({})", starting_point.to_string(tcx, true));
 }
 
 fn record_accesses<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -452,8 +450,8 @@ fn check_recursion_limit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     if recursion_depth > *tcx.sess.recursion_limit.get() {
         let error = format!("reached the recursion limit while instantiating `{}`",
                             instance);
-        if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
-            tcx.sess.span_fatal(tcx.hir().span(node_id), &error);
+        if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
+            tcx.sess.span_fatal(tcx.hir().span_by_hir_id(hir_id), &error);
         } else {
             tcx.sess.fatal(&error);
         }
@@ -484,8 +482,8 @@ fn check_type_length_limit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         let instance_name = instance.to_string();
         let msg = format!("reached the type-length limit while instantiating `{:.64}...`",
                           instance_name);
-        let mut diag = if let Some(node_id) = tcx.hir().as_local_node_id(instance.def_id()) {
-            tcx.sess.struct_span_fatal(tcx.hir().span(node_id), &msg)
+        let mut diag = if let Some(hir_id) = tcx.hir().as_local_hir_id(instance.def_id()) {
+            tcx.sess.struct_span_fatal(tcx.hir().span_by_hir_id(hir_id), &msg)
         } else {
             tcx.sess.struct_fatal(&msg)
         };
@@ -924,7 +922,7 @@ struct RootCollector<'b, 'a: 'b, 'tcx: 'a + 'b> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     mode: MonoItemCollectionMode,
     output: &'b mut Vec<MonoItem<'tcx>>,
-    entry_fn: Option<DefId>,
+    entry_fn: Option<(DefId, EntryFnType)>,
 }
 
 impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
@@ -1023,7 +1021,7 @@ impl<'b, 'a, 'v> RootCollector<'b, 'a, 'v> {
                 true
             }
             MonoItemCollectionMode::Lazy => {
-                self.entry_fn == Some(def_id) ||
+                self.entry_fn.map(|(id, _)| id) == Some(def_id) ||
                 self.tcx.is_reachable_non_generic(def_id) ||
                 self.tcx.codegen_fn_attrs(def_id).flags.contains(
                     CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
@@ -1048,14 +1046,9 @@ impl<'b, 'a, 'v> RootCollector<'b, 'a, 'v> {
     /// the return type of `main`. This is not needed when
     /// the user writes their own `start` manually.
     fn push_extra_entry_roots(&mut self) {
-        if self.tcx.sess.entry_fn.get().map(|e| e.2) != Some(config::EntryFnType::Main) {
-            return
-        }
-
-        let main_def_id = if let Some(def_id) = self.entry_fn {
-            def_id
-        } else {
-            return
+        let main_def_id = match self.entry_fn {
+            Some((def_id, EntryFnType::Main)) => def_id,
+            _ => return,
         };
 
         let start_def_id = match self.tcx.lang_items().require(StartFnLangItem) {
@@ -1097,7 +1090,10 @@ fn create_mono_items_for_default_impls<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             for param in &generics.params {
                 match param.kind {
                     hir::GenericParamKind::Lifetime { .. } => {}
-                    hir::GenericParamKind::Type { .. } => return,
+                    hir::GenericParamKind::Type { .. } |
+                    hir::GenericParamKind::Const { .. } => {
+                        return
+                    }
                 }
             }
 
@@ -1261,12 +1257,7 @@ fn collect_const<'a, 'tcx>(
     debug!("visiting const {:?}", constant);
 
     match constant.val {
-        ConstValue::ScalarPair(Scalar::Ptr(a), Scalar::Ptr(b)) => {
-            collect_miri(tcx, a.alloc_id, output);
-            collect_miri(tcx, b.alloc_id, output);
-        }
-        ConstValue::ScalarPair(_, Scalar::Ptr(ptr)) |
-        ConstValue::ScalarPair(Scalar::Ptr(ptr), _) |
+        ConstValue::Slice(Scalar::Ptr(ptr), _) |
         ConstValue::Scalar(Scalar::Ptr(ptr)) =>
             collect_miri(tcx, ptr.alloc_id, output),
         ConstValue::ByRef(_id, alloc, _offset) => {
diff --git a/src/librustc_mir/monomorphize/item.rs b/src/librustc_mir/monomorphize/item.rs
index 7014f539d5754..6e639c3a1179a 100644
--- a/src/librustc_mir/monomorphize/item.rs
+++ b/src/librustc_mir/monomorphize/item.rs
@@ -1,6 +1,6 @@
-use monomorphize::Instance;
+use crate::monomorphize::Instance;
 use rustc::hir;
-use rustc::hir::def_id::DefId;
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::session::config::OptLevel;
 use rustc::ty::{self, Ty, TyCtxt, ClosureSubsts, GeneratorSubsts};
 use rustc::ty::subst::Substs;
@@ -75,8 +75,7 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
 
         match *self.as_mono_item() {
             MonoItem::Fn(ref instance) => {
-                let entry_def_id =
-                    tcx.sess.entry_fn.borrow().map(|(id, _, _)| tcx.hir().local_def_id(id));
+                let entry_def_id = tcx.entry_fn(LOCAL_CRATE).map(|(id, _)| id);
                 // If this function isn't inlined or otherwise has explicit
                 // linkage, then we'll be creating a globally shared version.
                 if self.explicit_linkage(tcx).is_some() ||
@@ -123,7 +122,7 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
         codegen_fn_attrs.linkage
     }
 
-    /// Returns whether this instance is instantiable - whether it has no unsatisfied
+    /// Returns `true` if this instance is instantiable - whether it has no unsatisfied
     /// predicates.
     ///
     /// In order to codegen an item, all of its predicates must hold, because
@@ -160,14 +159,14 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
         tcx.substitute_normalize_and_test_predicates((def_id, &substs))
     }
 
-    fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
+    fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>, debug: bool) -> String {
         return match *self.as_mono_item() {
             MonoItem::Fn(instance) => {
-                to_string_internal(tcx, "fn ", instance)
+                to_string_internal(tcx, "fn ", instance, debug)
             },
             MonoItem::Static(def_id) => {
                 let instance = Instance::new(def_id, tcx.intern_substs(&[]));
-                to_string_internal(tcx, "static ", instance)
+                to_string_internal(tcx, "static ", instance, debug)
             },
             MonoItem::GlobalAsm(..) => {
                 "global_asm".to_string()
@@ -176,12 +175,13 @@ pub trait MonoItemExt<'a, 'tcx>: fmt::Debug {
 
         fn to_string_internal<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                         prefix: &str,
-                                        instance: Instance<'tcx>)
+                                        instance: Instance<'tcx>,
+                                        debug: bool)
                                         -> String {
             let mut result = String::with_capacity(32);
             result.push_str(prefix);
             let printer = DefPathBasedNames::new(tcx, false, false);
-            printer.push_instance_as_string(instance, &mut result);
+            printer.push_instance_as_string(instance, &mut result, debug);
             result
         }
     }
@@ -239,7 +239,13 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
         }
     }
 
-    pub fn push_type_name(&self, t: Ty<'tcx>, output: &mut String) {
+    // Pushes the type name of the specified type to the provided string.
+    // If 'debug' is true, printing normally unprintable types is allowed
+    // (e.g. ty::GeneratorWitness). This parameter should only be set when
+    // this method is being used for logging purposes (e.g. with debug! or info!)
+    // When being used for codegen purposes, 'debug' should be set to 'false'
+    // in order to catch unexpected types that should never end up in a type name
+    pub fn push_type_name(&self, t: Ty<'tcx>, output: &mut String, debug: bool) {
         match t.sty {
             ty::Bool              => output.push_str("bool"),
             ty::Char              => output.push_str("char"),
@@ -261,12 +267,12 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
             ty::Float(ast::FloatTy::F64) => output.push_str("f64"),
             ty::Adt(adt_def, substs) => {
                 self.push_def_path(adt_def.did, output);
-                self.push_type_params(substs, iter::empty(), output);
+                self.push_type_params(substs, iter::empty(), output, debug);
             },
             ty::Tuple(component_types) => {
                 output.push('(');
                 for &component_type in component_types {
-                    self.push_type_name(component_type, output);
+                    self.push_type_name(component_type, output, debug);
                     output.push_str(", ");
                 }
                 if !component_types.is_empty() {
@@ -282,7 +288,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                     hir::MutMutable => output.push_str("mut "),
                 }
 
-                self.push_type_name(inner_type, output);
+                self.push_type_name(inner_type, output, debug);
             },
             ty::Ref(_, inner_type, mutbl) => {
                 output.push('&');
@@ -290,17 +296,17 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                     output.push_str("mut ");
                 }
 
-                self.push_type_name(inner_type, output);
+                self.push_type_name(inner_type, output, debug);
             },
             ty::Array(inner_type, len) => {
                 output.push('[');
-                self.push_type_name(inner_type, output);
+                self.push_type_name(inner_type, output, debug);
                 write!(output, "; {}", len.unwrap_usize(self.tcx)).unwrap();
                 output.push(']');
             },
             ty::Slice(inner_type) => {
                 output.push('[');
-                self.push_type_name(inner_type, output);
+                self.push_type_name(inner_type, output, debug);
                 output.push(']');
             },
             ty::Dynamic(ref trait_data, ..) => {
@@ -310,6 +316,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                         principal.skip_binder().substs,
                         trait_data.projection_bounds(),
                         output,
+                        debug
                     );
                 } else {
                     output.push_str("dyn '_");
@@ -339,7 +346,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
 
                 if !sig.inputs().is_empty() {
                     for &parameter_type in sig.inputs() {
-                        self.push_type_name(parameter_type, output);
+                        self.push_type_name(parameter_type, output, debug);
                         output.push_str(", ");
                     }
                     output.pop();
@@ -358,7 +365,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
 
                 if !sig.output().is_unit() {
                     output.push_str(" -> ");
-                    self.push_type_name(sig.output(), output);
+                    self.push_type_name(sig.output(), output, debug);
                 }
             },
             ty::Generator(def_id, GeneratorSubsts { ref substs }, _) |
@@ -366,7 +373,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
                 self.push_def_path(def_id, output);
                 let generics = self.tcx.generics_of(self.tcx.closure_base_def_id(def_id));
                 let substs = substs.truncate_to(self.tcx, generics);
-                self.push_type_params(substs, iter::empty(), output);
+                self.push_type_params(substs, iter::empty(), output, debug);
             }
             ty::Error |
             ty::Bound(..) |
@@ -377,8 +384,12 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
             ty::Param(_) |
             ty::GeneratorWitness(_) |
             ty::Opaque(..) => {
-                bug!("DefPathBasedNames: Trying to create type name for \
+                if debug {
+                    output.push_str(&format!("`{:?}`", t));
+                } else {
+                    bug!("DefPathBasedNames: Trying to create type name for \
                                          unexpected type: {:?}", t);
+                }
             }
         }
     }
@@ -413,7 +424,8 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
     fn push_type_params<I>(&self,
                             substs: &Substs<'tcx>,
                             projections: I,
-                            output: &mut String)
+                            output: &mut String,
+                            debug: bool)
         where I: Iterator<Item=ty::PolyExistentialProjection<'tcx>>
     {
         let mut projections = projections.peekable();
@@ -424,7 +436,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
         output.push('<');
 
         for type_parameter in substs.types() {
-            self.push_type_name(type_parameter, output);
+            self.push_type_name(type_parameter, output, debug);
             output.push_str(", ");
         }
 
@@ -433,7 +445,7 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
             let name = &self.tcx.associated_item(projection.item_def_id).ident.as_str();
             output.push_str(name);
             output.push_str("=");
-            self.push_type_name(projection.ty, output);
+            self.push_type_name(projection.ty, output, debug);
             output.push_str(", ");
         }
 
@@ -445,8 +457,9 @@ impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
 
     pub fn push_instance_as_string(&self,
                                    instance: Instance<'tcx>,
-                                   output: &mut String) {
+                                   output: &mut String,
+                                   debug: bool) {
         self.push_def_path(instance.def_id(), output);
-        self.push_type_params(instance.substs, iter::empty(), output);
+        self.push_type_params(instance.substs, iter::empty(), output, debug);
     }
 }
diff --git a/src/librustc_mir/monomorphize/partitioning.rs b/src/librustc_mir/monomorphize/partitioning.rs
index c3613fbf04c1b..f342017603ed6 100644
--- a/src/librustc_mir/monomorphize/partitioning.rs
+++ b/src/librustc_mir/monomorphize/partitioning.rs
@@ -111,14 +111,14 @@ use rustc::util::common::time;
 use rustc::util::nodemap::{DefIdSet, FxHashMap, FxHashSet};
 use rustc::mir::mono::MonoItem;
 
-use monomorphize::collector::InliningMap;
-use monomorphize::collector::{self, MonoItemCollectionMode};
-use monomorphize::item::{MonoItemExt, InstantiationMode};
+use crate::monomorphize::collector::InliningMap;
+use crate::monomorphize::collector::{self, MonoItemCollectionMode};
+use crate::monomorphize::item::{MonoItemExt, InstantiationMode};
 
 pub use rustc::mir::mono::CodegenUnit;
 
 pub enum PartitioningStrategy {
-    /// Generate one codegen unit per source-level module.
+    /// Generates one codegen unit per source-level module.
     PerModule,
 
     /// Partition the whole crate into a fixed number of codegen units.
@@ -146,7 +146,7 @@ pub trait CodegenUnitExt<'tcx> {
         WorkProductId::from_cgu_name(&self.name().as_str())
     }
 
-    fn work_product(&self, tcx: TyCtxt) -> WorkProduct {
+    fn work_product(&self, tcx: TyCtxt<'_, '_, '_>) -> WorkProduct {
         let work_product_id = self.work_product_id();
         tcx.dep_graph
            .previous_work_product(&work_product_id)
@@ -213,7 +213,7 @@ impl<'tcx> CodegenUnitExt<'tcx> for CodegenUnit<'tcx> {
 }
 
 // Anything we can't find a proper codegen unit for goes into this.
-fn fallback_cgu_name(name_builder: &mut CodegenUnitNameBuilder) -> InternedString {
+fn fallback_cgu_name(name_builder: &mut CodegenUnitNameBuilder<'_, '_, '_>) -> InternedString {
     name_builder.build_cgu_name(LOCAL_CRATE, &["fallback"], Some("cgu"))
 }
 
@@ -536,7 +536,7 @@ fn mono_item_visibility(
     }
 }
 
-fn default_visibility(tcx: TyCtxt, id: DefId, is_generic: bool) -> Visibility {
+fn default_visibility(tcx: TyCtxt<'_, '_, '_>, id: DefId, is_generic: bool) -> Visibility {
     if !tcx.sess.target.target.options.default_hidden_visibility {
         return Visibility::Default
     }
@@ -795,8 +795,8 @@ fn characteristic_def_id_of_mono_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
 type CguNameCache = FxHashMap<(DefId, bool), InternedString>;
 
-fn compute_codegen_unit_name(tcx: TyCtxt,
-                             name_builder: &mut CodegenUnitNameBuilder,
+fn compute_codegen_unit_name(tcx: TyCtxt<'_, '_, '_>,
+                             name_builder: &mut CodegenUnitNameBuilder<'_, '_, '_>,
                              def_id: DefId,
                              volatile: bool,
                              cache: &mut CguNameCache)
@@ -855,7 +855,7 @@ fn compute_codegen_unit_name(tcx: TyCtxt,
     }).clone()
 }
 
-fn numbered_codegen_unit_name(name_builder: &mut CodegenUnitNameBuilder,
+fn numbered_codegen_unit_name(name_builder: &mut CodegenUnitNameBuilder<'_, '_, '_>,
                               index: usize)
                               -> InternedString {
     name_builder.build_cgu_name_no_mangle(LOCAL_CRATE, &["cgu"], Some(index))
@@ -879,7 +879,7 @@ fn debug_dump<'a, 'b, 'tcx, I>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                                    .unwrap_or("<no hash>");
 
                 debug!(" - {} [{:?}] [{}]",
-                       mono_item.to_string(tcx),
+                       mono_item.to_string(tcx, true),
                        linkage,
                        symbol_hash);
             }
@@ -929,7 +929,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
 
     tcx.sess.abort_if_errors();
 
-    ::monomorphize::assert_symbols_are_distinct(tcx, items.iter());
+    crate::monomorphize::assert_symbols_are_distinct(tcx, items.iter());
 
     let strategy = if tcx.sess.opts.incremental.is_some() {
         PartitioningStrategy::PerModule
@@ -971,7 +971,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
         let mut item_keys: Vec<_> = items
             .iter()
             .map(|i| {
-                let mut output = i.to_string(tcx);
+                let mut output = i.to_string(tcx, false);
                 output.push_str(" @@");
                 let mut empty = Vec::new();
                 let cgus = item_to_cgus.get_mut(i).unwrap_or(&mut empty);
@@ -1013,7 +1013,7 @@ fn collect_and_partition_mono_items<'a, 'tcx>(
     (Arc::new(mono_items), Arc::new(codegen_units))
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     providers.collect_and_partition_mono_items =
         collect_and_partition_mono_items;
 
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index 751815eab287b..d4145b8e47ea2 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -16,12 +16,14 @@ use syntax_pos::Span;
 use std::fmt;
 use std::iter;
 
-use transform::{add_moves_for_packed_drops, add_call_guards};
-use transform::{remove_noop_landing_pads, no_landing_pads, simplify};
-use util::elaborate_drops::{self, DropElaborator, DropStyle, DropFlagMode};
-use util::patch::MirPatch;
-
-pub fn provide(providers: &mut Providers) {
+use crate::transform::{
+    add_moves_for_packed_drops, add_call_guards,
+    remove_noop_landing_pads, no_landing_pads, simplify, run_passes
+};
+use crate::util::elaborate_drops::{self, DropElaborator, DropStyle, DropFlagMode};
+use crate::util::patch::MirPatch;
+
+pub fn provide(providers: &mut Providers<'_>) {
     providers.mir_shims = make_shim;
 }
 
@@ -113,12 +115,15 @@ fn make_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         }
     };
     debug!("make_shim({:?}) = untransformed {:?}", instance, result);
-    add_moves_for_packed_drops::add_moves_for_packed_drops(
-        tcx, &mut result, instance.def_id());
-    no_landing_pads::no_landing_pads(tcx, &mut result);
-    remove_noop_landing_pads::remove_noop_landing_pads(tcx, &mut result);
-    simplify::simplify_cfg(&mut result);
-    add_call_guards::CriticalCallEdges.add_call_guards(&mut result);
+
+    run_passes(tcx, &mut result, instance, MirPhase::Const, &[
+        &add_moves_for_packed_drops::AddMovesForPackedDrops,
+        &no_landing_pads::NoLandingPads,
+        &remove_noop_landing_pads::RemoveNoopLandingPads,
+        &simplify::SimplifyCfg::new("make_shim"),
+        &add_call_guards::CriticalCallEdges,
+    ]);
+
     debug!("make_shim({:?}) = {:?}", instance, result);
 
     tcx.alloc_mir(result)
@@ -138,7 +143,7 @@ enum CallKind {
     Direct(DefId),
 }
 
-fn temp_decl(mutability: Mutability, ty: Ty, span: Span) -> LocalDecl {
+fn temp_decl(mutability: Mutability, ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
     let source_info = SourceInfo { scope: OUTERMOST_SOURCE_SCOPE, span };
     LocalDecl {
         mutability,
@@ -259,7 +264,7 @@ pub struct DropShimElaborator<'a, 'tcx: 'a> {
 }
 
 impl<'a, 'tcx> fmt::Debug for DropShimElaborator<'a, 'tcx> {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
         Ok(())
     }
 }
@@ -301,7 +306,7 @@ impl<'a, 'tcx> DropElaborator<'a, 'tcx> for DropShimElaborator<'a, 'tcx> {
     }
 }
 
-/// Build a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
+/// Builds a `Clone::clone` shim for `self_ty`. Here, `def_id` is `Clone::clone`.
 fn build_clone_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                               def_id: DefId,
                               self_ty: Ty<'tcx>)
@@ -459,7 +464,7 @@ impl<'a, 'tcx> CloneShimBuilder<'a, 'tcx> {
             span: self.span,
             ty: func_ty,
             user_ty: None,
-            literal: tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::zero_sized(func_ty),
             )),
         });
@@ -521,7 +526,7 @@ impl<'a, 'tcx> CloneShimBuilder<'a, 'tcx> {
             span: self.span,
             ty: self.tcx.types.usize,
             user_ty: None,
-            literal: self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::from_usize(self.tcx, value),
             )),
         }
@@ -686,7 +691,7 @@ impl<'a, 'tcx> CloneShimBuilder<'a, 'tcx> {
     }
 }
 
-/// Build a "call" shim for `def_id`. The shim calls the
+/// Builds a "call" shim for `def_id`. The shim calls the
 /// function specified by `call_kind`, first adjusting its first
 /// argument according to `rcvr_adjustment`.
 ///
@@ -759,7 +764,7 @@ fn build_call_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 span,
                 ty,
                 user_ty: None,
-                literal: tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+                literal: tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                     ty::Const::zero_sized(ty)
                 )),
              }),
diff --git a/src/librustc_mir/transform/add_call_guards.rs b/src/librustc_mir/transform/add_call_guards.rs
index 3ea1c8e82ff2b..88042d64e96b7 100644
--- a/src/librustc_mir/transform/add_call_guards.rs
+++ b/src/librustc_mir/transform/add_call_guards.rs
@@ -1,7 +1,7 @@
 use rustc::ty::TyCtxt;
 use rustc::mir::*;
 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 #[derive(PartialEq)]
 pub enum AddCallGuards {
@@ -33,14 +33,14 @@ pub use self::AddCallGuards::*;
 impl MirPass for AddCallGuards {
     fn run_pass<'a, 'tcx>(&self,
                           _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         self.add_call_guards(mir);
     }
 }
 
 impl AddCallGuards {
-    pub fn add_call_guards(&self, mir: &mut Mir) {
+    pub fn add_call_guards(&self, mir: &mut Mir<'_>) {
         let pred_count: IndexVec<_, _> =
             mir.predecessors().iter().map(|ps| ps.len()).collect();
 
diff --git a/src/librustc_mir/transform/add_moves_for_packed_drops.rs b/src/librustc_mir/transform/add_moves_for_packed_drops.rs
index 8ec6902cf15fd..4d4c89b8b6a40 100644
--- a/src/librustc_mir/transform/add_moves_for_packed_drops.rs
+++ b/src/librustc_mir/transform/add_moves_for_packed_drops.rs
@@ -2,9 +2,9 @@ use rustc::hir::def_id::DefId;
 use rustc::mir::*;
 use rustc::ty::TyCtxt;
 
-use transform::{MirPass, MirSource};
-use util::patch::MirPatch;
-use util;
+use crate::transform::{MirPass, MirSource};
+use crate::util::patch::MirPatch;
+use crate::util;
 
 // This pass moves values being dropped that are within a packed
 // struct to a separate local before dropping them, to ensure that
@@ -42,11 +42,11 @@ pub struct AddMovesForPackedDrops;
 impl MirPass for AddMovesForPackedDrops {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          src: MirSource,
+                          src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>)
     {
         debug!("add_moves_for_packed_drops({:?} @ {:?})", src, mir.span);
-        add_moves_for_packed_drops(tcx, mir, src.def_id);
+        add_moves_for_packed_drops(tcx, mir, src.def_id());
     }
 }
 
diff --git a/src/librustc_mir/transform/add_retag.rs b/src/librustc_mir/transform/add_retag.rs
index 3d5897bca9f52..e66c11aa36e0e 100644
--- a/src/librustc_mir/transform/add_retag.rs
+++ b/src/librustc_mir/transform/add_retag.rs
@@ -6,7 +6,7 @@
 
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::mir::*;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct AddRetag;
 
@@ -77,7 +77,7 @@ fn may_have_reference<'a, 'gcx, 'tcx>(ty: Ty<'tcx>, tcx: TyCtxt<'a, 'gcx, 'tcx>)
 impl MirPass for AddRetag {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>)
     {
         if !tcx.sess.opts.debugging_opts.mir_emit_retag {
diff --git a/src/librustc_mir/transform/check_unsafety.rs b/src/librustc_mir/transform/check_unsafety.rs
index eb151b56bed65..66529e579835d 100644
--- a/src/librustc_mir/transform/check_unsafety.rs
+++ b/src/librustc_mir/transform/check_unsafety.rs
@@ -4,6 +4,7 @@ use rustc_data_structures::sync::Lrc;
 
 use rustc::ty::query::Providers;
 use rustc::ty::{self, TyCtxt};
+use rustc::ty::cast::CastTy;
 use rustc::hir;
 use rustc::hir::Node;
 use rustc::hir::def_id::DefId;
@@ -16,31 +17,38 @@ use syntax::symbol::Symbol;
 
 use std::ops::Bound;
 
-use util;
+use crate::util;
 
 pub struct UnsafetyChecker<'a, 'tcx: 'a> {
     mir: &'a Mir<'tcx>,
+    const_context: bool,
     min_const_fn: bool,
     source_scope_local_data: &'a IndexVec<SourceScope, SourceScopeLocalData>,
     violations: Vec<UnsafetyViolation>,
     source_info: SourceInfo,
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     param_env: ty::ParamEnv<'tcx>,
-    /// mark an `unsafe` block as used, so we don't lint it
+    /// Mark an `unsafe` block as used, so we don't lint it.
     used_unsafe: FxHashSet<ast::NodeId>,
     inherited_blocks: Vec<(ast::NodeId, bool)>,
 }
 
 impl<'a, 'gcx, 'tcx> UnsafetyChecker<'a, 'tcx> {
     fn new(
+        const_context: bool,
         min_const_fn: bool,
         mir: &'a Mir<'tcx>,
         source_scope_local_data: &'a IndexVec<SourceScope, SourceScopeLocalData>,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> Self {
+        // sanity check
+        if min_const_fn {
+            assert!(const_context);
+        }
         Self {
             mir,
+            const_context,
             min_const_fn,
             source_scope_local_data,
             violations: vec![],
@@ -124,29 +132,70 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
                     rvalue: &Rvalue<'tcx>,
                     location: Location)
     {
-        if let &Rvalue::Aggregate(box ref aggregate, _) = rvalue {
-            match aggregate {
-                &AggregateKind::Array(..) |
-                &AggregateKind::Tuple => {}
-                &AggregateKind::Adt(ref def, ..) => {
-                    match self.tcx.layout_scalar_valid_range(def.did) {
-                        (Bound::Unbounded, Bound::Unbounded) => {},
-                        _ => self.require_unsafe(
-                            "initializing type with `rustc_layout_scalar_valid_range` attr",
-                            "initializing a layout restricted type's field with a value outside \
-                            the valid range is undefined behavior",
-                            UnsafetyViolationKind::GeneralAndConstFn,
-                        ),
+        match rvalue {
+            Rvalue::Aggregate(box ref aggregate, _) => {
+                match aggregate {
+                    &AggregateKind::Array(..) |
+                    &AggregateKind::Tuple => {}
+                    &AggregateKind::Adt(ref def, ..) => {
+                        match self.tcx.layout_scalar_valid_range(def.did) {
+                            (Bound::Unbounded, Bound::Unbounded) => {},
+                            _ => self.require_unsafe(
+                                "initializing type with `rustc_layout_scalar_valid_range` attr",
+                                "initializing a layout restricted type's field with a value \
+                                outside the valid range is undefined behavior",
+                                UnsafetyViolationKind::GeneralAndConstFn,
+                            ),
+                        }
+                    }
+                    &AggregateKind::Closure(def_id, _) |
+                    &AggregateKind::Generator(def_id, _, _) => {
+                        let UnsafetyCheckResult {
+                            violations, unsafe_blocks
+                        } = self.tcx.unsafety_check_result(def_id);
+                        self.register_violations(&violations, &unsafe_blocks);
                     }
                 }
-                &AggregateKind::Closure(def_id, _) |
-                &AggregateKind::Generator(def_id, _, _) => {
-                    let UnsafetyCheckResult {
-                        violations, unsafe_blocks
-                    } = self.tcx.unsafety_check_result(def_id);
-                    self.register_violations(&violations, &unsafe_blocks);
+            },
+            // casting pointers to ints is unsafe in const fn because the const evaluator cannot
+            // possibly know what the result of various operations like `address / 2` would be
+            // pointers during const evaluation have no integral address, only an abstract one
+            Rvalue::Cast(CastKind::Misc, ref operand, cast_ty)
+            if self.const_context && self.tcx.features().const_raw_ptr_to_usize_cast => {
+                let operand_ty = operand.ty(self.mir, self.tcx);
+                let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast");
+                let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
+                match (cast_in, cast_out) {
+                    (CastTy::Ptr(_), CastTy::Int(_)) |
+                    (CastTy::FnPtr, CastTy::Int(_)) => {
+                        self.register_violations(&[UnsafetyViolation {
+                            source_info: self.source_info,
+                            description: Symbol::intern("cast of pointer to int").as_interned_str(),
+                            details: Symbol::intern("casting pointers to integers in constants")
+                                     .as_interned_str(),
+                            kind: UnsafetyViolationKind::General,
+                        }], &[]);
+                    },
+                    _ => {},
                 }
             }
+            // raw pointer and fn pointer operations are unsafe as it is not clear whether one
+            // pointer would be "less" or "equal" to another, because we cannot know where llvm
+            // or the linker will place various statics in memory. Without this information the
+            // result of a comparison of addresses would differ between runtime and compile-time.
+            Rvalue::BinaryOp(_, ref lhs, _)
+            if self.const_context && self.tcx.features().const_compare_raw_pointers => {
+                if let ty::RawPtr(_) | ty::FnPtr(..) = lhs.ty(self.mir, self.tcx).sty {
+                    self.register_violations(&[UnsafetyViolation {
+                        source_info: self.source_info,
+                        description: Symbol::intern("pointer operation").as_interned_str(),
+                        details: Symbol::intern("operations on pointers in constants")
+                                 .as_interned_str(),
+                        kind: UnsafetyViolationKind::General,
+                    }], &[]);
+                }
+            }
+            _ => {},
         }
         self.super_rvalue(rvalue, location);
     }
@@ -409,7 +458,7 @@ impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> {
     }
 }
 
-pub(crate) fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         unsafety_check_result,
         unsafe_derive_on_repr_packed,
@@ -484,8 +533,16 @@ fn unsafety_check_result<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
     };
 
     let param_env = tcx.param_env(def_id);
+
+    let id = tcx.hir().as_local_node_id(def_id).unwrap();
+    let (const_context, min_const_fn) = match tcx.hir().body_owner_kind(id) {
+        hir::BodyOwnerKind::Closure => (false, false),
+        hir::BodyOwnerKind::Fn => (tcx.is_const_fn(def_id), tcx.is_min_const_fn(def_id)),
+        hir::BodyOwnerKind::Const |
+        hir::BodyOwnerKind::Static(_) => (true, false),
+    };
     let mut checker = UnsafetyChecker::new(
-        tcx.is_min_const_fn(def_id),
+        const_context, min_const_fn,
         mir, source_scope_local_data, tcx, param_env);
     checker.visit_mir(mir);
 
@@ -517,8 +574,8 @@ fn unsafe_derive_on_repr_packed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: D
                   &message);
 }
 
-/// Return the NodeId for an enclosing scope that is also `unsafe`
-fn is_enclosed(tcx: TyCtxt,
+/// Returns the `NodeId` for an enclosing scope that is also `unsafe`.
+fn is_enclosed(tcx: TyCtxt<'_, '_, '_>,
                used_unsafe: &FxHashSet<ast::NodeId>,
                id: ast::NodeId) -> Option<(String, ast::NodeId)> {
     let parent_id = tcx.hir().get_parent_node(id);
@@ -541,7 +598,9 @@ fn is_enclosed(tcx: TyCtxt,
     }
 }
 
-fn report_unused_unsafe(tcx: TyCtxt, used_unsafe: &FxHashSet<ast::NodeId>, id: ast::NodeId) {
+fn report_unused_unsafe(tcx: TyCtxt<'_, '_, '_>,
+                        used_unsafe: &FxHashSet<ast::NodeId>,
+                        id: ast::NodeId) {
     let span = tcx.sess.source_map().def_span(tcx.hir().span(id));
     let msg = "unnecessary `unsafe` block";
     let mut db = tcx.struct_span_lint_node(UNUSED_UNSAFE, id, span, msg);
diff --git a/src/librustc_mir/transform/cleanup_post_borrowck.rs b/src/librustc_mir/transform/cleanup_post_borrowck.rs
index e6df6b7fd2724..890d2c56f42b2 100644
--- a/src/librustc_mir/transform/cleanup_post_borrowck.rs
+++ b/src/librustc_mir/transform/cleanup_post_borrowck.rs
@@ -26,7 +26,7 @@ use rustc::mir::{BasicBlock, FakeReadCause, Local, Location, Mir, Place};
 use rustc::mir::{Statement, StatementKind};
 use rustc::mir::visit::MutVisitor;
 use rustc::ty::TyCtxt;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct CleanAscribeUserType;
 
@@ -35,7 +35,7 @@ pub struct DeleteAscribeUserType;
 impl MirPass for CleanAscribeUserType {
     fn run_pass<'a, 'tcx>(&self,
                           _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _source: MirSource,
+                          _source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let mut delete = DeleteAscribeUserType;
         delete.visit_mir(mir);
@@ -69,7 +69,7 @@ pub struct DeleteFakeBorrows {
 impl MirPass for CleanFakeReadsAndBorrows {
     fn run_pass<'a, 'tcx>(&self,
                           _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _source: MirSource,
+                          _source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let mut delete_reads = DeleteAndRecordFakeReads::default();
         delete_reads.visit_mir(mir);
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 03d6d3868c9f0..7da00c4ea0c36 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -18,19 +18,18 @@ use rustc::ty::layout::{
     HasTyCtxt, TargetDataLayout, HasDataLayout,
 };
 
-use interpret::{self, EvalContext, ScalarMaybeUndef, Immediate, OpTy, MemoryKind};
-use const_eval::{
-    CompileTimeInterpreter, error_to_const_error, eval_promoted, mk_borrowck_eval_cx,
-    lazy_const_to_op,
+use crate::interpret::{EvalContext, ScalarMaybeUndef, Immediate, OpTy, ImmTy, MemoryKind};
+use crate::const_eval::{
+    CompileTimeInterpreter, error_to_const_error, eval_promoted, mk_eval_cx,
 };
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct ConstProp;
 
 impl MirPass for ConstProp {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          source: MirSource,
+                          source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         // will be evaluated by miri and produce its errors there
         if source.promoted.is_some() {
@@ -38,11 +37,11 @@ impl MirPass for ConstProp {
         }
 
         use rustc::hir::map::blocks::FnLikeNode;
-        let node_id = tcx.hir().as_local_node_id(source.def_id)
+        let node_id = tcx.hir().as_local_node_id(source.def_id())
                              .expect("Non-local call to local provider is_const_fn");
 
         let is_fn_like = FnLikeNode::from_node(tcx.hir().get(node_id)).is_some();
-        let is_assoc_const = match tcx.describe_def(source.def_id) {
+        let is_assoc_const = match tcx.describe_def(source.def_id()) {
             Some(Def::AssociatedConst(_)) => true,
             _ => false,
         };
@@ -50,11 +49,11 @@ impl MirPass for ConstProp {
         // Only run const prop on functions, methods, closures and associated constants
         if !is_fn_like && !is_assoc_const  {
             // skip anon_const/statics/consts because they'll be evaluated by miri anyway
-            trace!("ConstProp skipped for {:?}", source.def_id);
+            trace!("ConstProp skipped for {:?}", source.def_id());
             return
         }
 
-        trace!("ConstProp starting for {:?}", source.def_id);
+        trace!("ConstProp starting for {:?}", source.def_id());
 
         // FIXME(oli-obk, eddyb) Optimize locals (or even local paths) to hold
         // constants, instead of just checking for const-folding succeeding.
@@ -63,7 +62,7 @@ impl MirPass for ConstProp {
         let mut optimization_finder = ConstPropagator::new(mir, tcx, source);
         optimization_finder.visit_mir(mir);
 
-        trace!("ConstProp done for {:?}", source.def_id);
+        trace!("ConstProp done for {:?}", source.def_id());
     }
 }
 
@@ -74,7 +73,7 @@ struct ConstPropagator<'a, 'mir, 'tcx:'a+'mir> {
     ecx: EvalContext<'a, 'mir, 'tcx, CompileTimeInterpreter<'a, 'mir, 'tcx>>,
     mir: &'mir Mir<'tcx>,
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    source: MirSource,
+    source: MirSource<'tcx>,
     places: IndexVec<Local, Option<Const<'tcx>>>,
     can_const_prop: IndexVec<Local, bool>,
     param_env: ParamEnv<'tcx>,
@@ -107,12 +106,10 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
     fn new(
         mir: &'mir Mir<'tcx>,
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
-        source: MirSource,
+        source: MirSource<'tcx>,
     ) -> ConstPropagator<'a, 'mir, 'tcx> {
-        let param_env = tcx.param_env(source.def_id);
-        let substs = Substs::identity_for_item(tcx, source.def_id);
-        let instance = Instance::new(source.def_id, substs);
-        let ecx = mk_borrowck_eval_cx(tcx, instance, mir, DUMMY_SP).unwrap();
+        let param_env = tcx.param_env(source.def_id());
+        let ecx = mk_eval_cx(tcx, tcx.def_span(source.def_id()), param_env);
         ConstPropagator {
             ecx,
             mir,
@@ -256,7 +253,7 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
         source_info: SourceInfo,
     ) -> Option<Const<'tcx>> {
         self.ecx.tcx.span = source_info.span;
-        match lazy_const_to_op(&self.ecx, *c.literal, c.ty) {
+        match self.ecx.lazy_const_to_op(*c.literal, c.ty) {
             Ok(op) => {
                 Some((op, c.span))
             },
@@ -286,13 +283,13 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                 _ => None,
             },
             Place::Promoted(ref promoted) => {
-                let generics = self.tcx.generics_of(self.source.def_id);
+                let generics = self.tcx.generics_of(self.source.def_id());
                 if generics.requires_monomorphization(self.tcx) {
                     // FIXME: can't handle code with generics
                     return None;
                 }
-                let substs = Substs::identity_for_item(self.tcx, self.source.def_id);
-                let instance = Instance::new(self.source.def_id, substs);
+                let substs = Substs::identity_for_item(self.tcx, self.source.def_id());
+                let instance = Instance::new(self.source.def_id(), substs);
                 let cid = GlobalId {
                     instance,
                     promoted: Some(promoted.0),
@@ -347,23 +344,23 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
             Rvalue::Len(_) => None,
             Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
                 type_size_of(self.tcx, self.param_env, ty).and_then(|n| Some((
-                    OpTy {
-                        op: interpret::Operand::Immediate(Immediate::Scalar(
+                    ImmTy {
+                        imm: Immediate::Scalar(
                             Scalar::Bits {
                                 bits: n as u128,
                                 size: self.tcx.data_layout.pointer_size.bytes() as u8,
                             }.into()
-                        )),
+                        ),
                         layout: self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
-                    },
+                    }.into(),
                     span,
                 )))
             }
             Rvalue::UnaryOp(op, ref arg) => {
-                let def_id = if self.tcx.is_closure(self.source.def_id) {
-                    self.tcx.closure_base_def_id(self.source.def_id)
+                let def_id = if self.tcx.is_closure(self.source.def_id()) {
+                    self.tcx.closure_base_def_id(self.source.def_id())
                 } else {
-                    self.source.def_id
+                    self.source.def_id()
                 };
                 let generics = self.tcx.generics_of(def_id);
                 if generics.requires_monomorphization(self.tcx) {
@@ -373,13 +370,12 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
 
                 let (arg, _) = self.eval_operand(arg, source_info)?;
                 let val = self.use_ecx(source_info, |this| {
-                    let prim = this.ecx.read_scalar(arg)?.not_undef()?;
+                    let prim = this.ecx.read_immediate(arg)?;
                     match op {
                         UnOp::Neg => {
                             // Need to do overflow check here: For actual CTFE, MIR
                             // generation emits code that does this before calling the op.
-                            let size = arg.layout.size;
-                            if prim.to_bits(size)? == (1 << (size.bits() - 1)) {
+                            if prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) {
                                 return err!(OverflowNeg);
                             }
                         }
@@ -388,22 +384,22 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                         }
                     }
                     // Now run the actual operation.
-                    this.ecx.unary_op(op, prim, arg.layout)
+                    this.ecx.unary_op(op, prim)
                 })?;
-                let res = OpTy {
-                    op: interpret::Operand::Immediate(Immediate::Scalar(val.into())),
+                let res = ImmTy {
+                    imm: Immediate::Scalar(val.into()),
                     layout: place_layout,
                 };
-                Some((res, span))
+                Some((res.into(), span))
             }
             Rvalue::CheckedBinaryOp(op, ref left, ref right) |
             Rvalue::BinaryOp(op, ref left, ref right) => {
                 trace!("rvalue binop {:?} for {:?} and {:?}", op, left, right);
                 let right = self.eval_operand(right, source_info)?;
-                let def_id = if self.tcx.is_closure(self.source.def_id) {
-                    self.tcx.closure_base_def_id(self.source.def_id)
+                let def_id = if self.tcx.is_closure(self.source.def_id()) {
+                    self.tcx.closure_base_def_id(self.source.def_id())
                 } else {
-                    self.source.def_id
+                    self.source.def_id()
                 };
                 let generics = self.tcx.generics_of(def_id);
                 if generics.requires_monomorphization(self.tcx) {
@@ -449,7 +445,7 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                 })?;
                 trace!("const evaluating {:?} for {:?} and {:?}", op, left, right);
                 let (val, overflow) = self.use_ecx(source_info, |this| {
-                    this.ecx.binary_op_imm(op, l, r)
+                    this.ecx.binary_op(op, l, r)
                 })?;
                 let val = if let Rvalue::CheckedBinaryOp(..) = *rvalue {
                     Immediate::ScalarPair(
@@ -464,11 +460,11 @@ impl<'a, 'mir, 'tcx> ConstPropagator<'a, 'mir, 'tcx> {
                     }
                     Immediate::Scalar(val.into())
                 };
-                let res = OpTy {
-                    op: interpret::Operand::Immediate(val),
+                let res = ImmTy {
+                    imm: val,
                     layout: place_layout,
                 };
-                Some((res, span))
+                Some((res.into(), span))
             },
         }
     }
@@ -488,7 +484,7 @@ struct CanConstProp {
 
 impl CanConstProp {
     /// returns true if `local` can be propagated
-    fn check(mir: &Mir) -> IndexVec<Local, bool> {
+    fn check(mir: &Mir<'_>) -> IndexVec<Local, bool> {
         let mut cpv = CanConstProp {
             can_const_prop: IndexVec::from_elem(true, &mir.local_decls),
             found_assignment: IndexVec::from_elem(false, &mir.local_decls),
@@ -610,7 +606,7 @@ impl<'b, 'a, 'tcx> Visitor<'tcx> for ConstPropagator<'b, 'a, 'tcx> {
                     let node_id = self
                         .tcx
                         .hir()
-                        .as_local_node_id(self.source.def_id)
+                        .as_local_node_id(self.source.def_id())
                         .expect("some part of a failing const eval must be local");
                     use rustc::mir::interpret::EvalErrorKind::*;
                     let msg = match msg {
diff --git a/src/librustc_mir/transform/copy_prop.rs b/src/librustc_mir/transform/copy_prop.rs
index 55e14077c3ed0..7d907ca3a215e 100644
--- a/src/librustc_mir/transform/copy_prop.rs
+++ b/src/librustc_mir/transform/copy_prop.rs
@@ -22,15 +22,15 @@
 use rustc::mir::{Constant, Local, LocalKind, Location, Place, Mir, Operand, Rvalue, StatementKind};
 use rustc::mir::visit::MutVisitor;
 use rustc::ty::TyCtxt;
-use transform::{MirPass, MirSource};
-use util::def_use::DefUseAnalysis;
+use crate::transform::{MirPass, MirSource};
+use crate::util::def_use::DefUseAnalysis;
 
 pub struct CopyPropagation;
 
 impl MirPass for CopyPropagation {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _source: MirSource,
+                          _source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         // We only run when the MIR optimization level is > 1.
         // This avoids a slow pass, and messing up debug info.
@@ -173,7 +173,7 @@ enum Action<'tcx> {
 }
 
 impl<'tcx> Action<'tcx> {
-    fn local_copy(mir: &Mir<'tcx>, def_use_analysis: &DefUseAnalysis, src_place: &Place<'tcx>)
+    fn local_copy(mir: &Mir<'tcx>, def_use_analysis: &DefUseAnalysis<'_>, src_place: &Place<'tcx>)
                   -> Option<Action<'tcx>> {
         // The source must be a local.
         let src_local = if let Place::Local(local) = *src_place {
diff --git a/src/librustc_mir/transform/deaggregator.rs b/src/librustc_mir/transform/deaggregator.rs
index a2fe9def8eeba..9061dfff76fe8 100644
--- a/src/librustc_mir/transform/deaggregator.rs
+++ b/src/librustc_mir/transform/deaggregator.rs
@@ -1,14 +1,14 @@
 use rustc::ty::TyCtxt;
 use rustc::mir::*;
 use rustc_data_structures::indexed_vec::Idx;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct Deaggregator;
 
 impl MirPass for Deaggregator {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _source: MirSource,
+                          _source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let (basic_blocks, local_decls) = mir.basic_blocks_and_local_decls_mut();
         let local_decls = &*local_decls;
diff --git a/src/librustc_mir/transform/dump_mir.rs b/src/librustc_mir/transform/dump_mir.rs
index 8fabb2d11fc46..81e48fe2dbe3b 100644
--- a/src/librustc_mir/transform/dump_mir.rs
+++ b/src/librustc_mir/transform/dump_mir.rs
@@ -8,8 +8,8 @@ use std::io;
 use rustc::mir::Mir;
 use rustc::session::config::{OutputFilenames, OutputType};
 use rustc::ty::TyCtxt;
-use transform::{MirPass, MirSource};
-use util as mir_util;
+use crate::transform::{MirPass, MirSource};
+use crate::util as mir_util;
 
 pub struct Marker(pub &'static str);
 
@@ -20,7 +20,7 @@ impl MirPass for Marker {
 
     fn run_pass<'a, 'tcx>(&self,
                           _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _source: MirSource,
+                          _source: MirSource<'tcx>,
                           _mir: &mut Mir<'tcx>)
     {
     }
@@ -31,7 +31,7 @@ pub struct Disambiguator {
 }
 
 impl fmt::Display for Disambiguator {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         let title = if self.is_after { "after" } else { "before" };
         write!(formatter, "{}", title)
     }
@@ -41,7 +41,7 @@ impl fmt::Display for Disambiguator {
 pub fn on_mir_pass<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                              pass_num: &dyn fmt::Display,
                              pass_name: &str,
-                             source: MirSource,
+                             source: MirSource<'tcx>,
                              mir: &Mir<'tcx>,
                              is_after: bool) {
     if mir_util::dump_enabled(tcx, pass_name, source) {
diff --git a/src/librustc_mir/transform/elaborate_drops.rs b/src/librustc_mir/transform/elaborate_drops.rs
index 06e16de8b43bc..0f8db5f7334bd 100644
--- a/src/librustc_mir/transform/elaborate_drops.rs
+++ b/src/librustc_mir/transform/elaborate_drops.rs
@@ -1,10 +1,14 @@
-use dataflow::move_paths::{HasMoveData, MoveData, MovePathIndex, LookupResult};
-use dataflow::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
-use dataflow::{DataflowResults};
-use dataflow::{on_all_children_bits, on_all_drop_children_bits};
-use dataflow::{drop_flag_effects_for_location, on_lookup_result_bits};
-use dataflow::MoveDataParamEnv;
-use dataflow::{self, do_dataflow, DebugFormatted};
+use crate::dataflow::move_paths::{HasMoveData, MoveData, MovePathIndex, LookupResult};
+use crate::dataflow::{MaybeInitializedPlaces, MaybeUninitializedPlaces};
+use crate::dataflow::{DataflowResults};
+use crate::dataflow::{on_all_children_bits, on_all_drop_children_bits};
+use crate::dataflow::{drop_flag_effects_for_location, on_lookup_result_bits};
+use crate::dataflow::MoveDataParamEnv;
+use crate::dataflow::{self, do_dataflow, DebugFormatted};
+use crate::transform::{MirPass, MirSource};
+use crate::util::patch::MirPatch;
+use crate::util::elaborate_drops::{DropFlagState, Unwind, elaborate_drop};
+use crate::util::elaborate_drops::{DropElaborator, DropStyle, DropFlagMode};
 use rustc::ty::{self, TyCtxt};
 use rustc::ty::layout::VariantIdx;
 use rustc::mir::*;
@@ -13,23 +17,19 @@ use rustc_data_structures::bit_set::BitSet;
 use std::fmt;
 use syntax::ast;
 use syntax_pos::Span;
-use transform::{MirPass, MirSource};
-use util::patch::MirPatch;
-use util::elaborate_drops::{DropFlagState, Unwind, elaborate_drop};
-use util::elaborate_drops::{DropElaborator, DropStyle, DropFlagMode};
 
 pub struct ElaborateDrops;
 
 impl MirPass for ElaborateDrops {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          src: MirSource,
+                          src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>)
     {
         debug!("elaborate_drops({:?} @ {:?})", src, mir.span);
 
-        let id = tcx.hir().as_local_node_id(src.def_id).unwrap();
-        let param_env = tcx.param_env(src.def_id).with_reveal_all();
+        let id = tcx.hir().as_local_node_id(src.def_id()).unwrap();
+        let param_env = tcx.param_env(src.def_id()).with_reveal_all();
         let move_data = match MoveData::gather_moves(mir, tcx) {
             Ok(move_data) => move_data,
             Err((move_data, _move_errors)) => {
@@ -74,7 +74,7 @@ impl MirPass for ElaborateDrops {
     }
 }
 
-/// Return the set of basic blocks whose unwind edges are known
+/// Returns the set of basic blocks whose unwind edges are known
 /// to not be reachable, because they are `drop` terminators
 /// that can't drop anything.
 fn find_dead_unwinds<'a, 'tcx>(
@@ -174,7 +174,7 @@ struct Elaborator<'a, 'b: 'a, 'tcx: 'b> {
 }
 
 impl<'a, 'b, 'tcx> fmt::Debug for Elaborator<'a, 'b, 'tcx> {
-    fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Ok(())
     }
 }
@@ -533,7 +533,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> {
             span,
             ty: self.tcx.types.bool,
             user_ty: None,
-            literal: self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::from_bool(self.tcx, val),
             )),
         })))
diff --git a/src/librustc_mir/transform/erase_regions.rs b/src/librustc_mir/transform/erase_regions.rs
index b464b7d65e466..84f209f8776d9 100644
--- a/src/librustc_mir/transform/erase_regions.rs
+++ b/src/librustc_mir/transform/erase_regions.rs
@@ -1,14 +1,14 @@
 //! This pass erases all early-bound regions from the types occurring in the MIR.
 //! We want to do this once just before codegen, so codegen does not have to take
 //! care erasing regions all over the place.
-//! NOTE:  We do NOT erase regions of statements that are relevant for
-//! "types-as-contracts"-validation, namely, AcquireValid, ReleaseValid
+//! N.B., we do _not_ erase regions of statements that are relevant for
+//! "types-as-contracts"-validation, namely, `AcquireValid` and `ReleaseValid`.
 
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::mir::*;
 use rustc::mir::visit::{MutVisitor, TyContext};
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 struct EraseRegionsVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -53,7 +53,7 @@ pub struct EraseRegions;
 impl MirPass for EraseRegions {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _: MirSource,
+                          _: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         EraseRegionsVisitor::new(tcx).visit_mir(mir);
     }
diff --git a/src/librustc_mir/transform/generator.rs b/src/librustc_mir/transform/generator.rs
index ec0c118634d0f..0866b87cf17e6 100644
--- a/src/librustc_mir/transform/generator.rs
+++ b/src/librustc_mir/transform/generator.rs
@@ -56,19 +56,19 @@ use rustc::mir::visit::{PlaceContext, Visitor, MutVisitor};
 use rustc::ty::{self, TyCtxt, AdtDef, Ty};
 use rustc::ty::layout::VariantIdx;
 use rustc::ty::subst::Substs;
-use util::dump_mir;
-use util::liveness::{self, IdentityMap};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
 use rustc_data_structures::bit_set::BitSet;
 use std::borrow::Cow;
 use std::iter::once;
 use std::mem;
-use transform::{MirPass, MirSource};
-use transform::simplify;
-use transform::no_landing_pads::no_landing_pads;
-use dataflow::{do_dataflow, DebugFormatted, state_for_location};
-use dataflow::{MaybeStorageLive, HaveBeenBorrowedLocals};
+use crate::transform::{MirPass, MirSource};
+use crate::transform::simplify;
+use crate::transform::no_landing_pads::no_landing_pads;
+use crate::dataflow::{do_dataflow, DebugFormatted, state_for_location};
+use crate::dataflow::{MaybeStorageLive, HaveBeenBorrowedLocals};
+use crate::util::dump_mir;
+use crate::util::liveness::{self, IdentityMap};
 
 pub struct StateTransform;
 
@@ -113,6 +113,33 @@ impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor {
     }
 }
 
+struct PinArgVisitor<'tcx> {
+    ref_gen_ty: Ty<'tcx>,
+}
+
+impl<'tcx> MutVisitor<'tcx> for PinArgVisitor<'tcx> {
+    fn visit_local(&mut self,
+                   local: &mut Local,
+                   _: PlaceContext<'tcx>,
+                   _: Location) {
+        assert_ne!(*local, self_arg());
+    }
+
+    fn visit_place(&mut self,
+                    place: &mut Place<'tcx>,
+                    context: PlaceContext<'tcx>,
+                    location: Location) {
+        if *place == Place::Local(self_arg()) {
+            *place = Place::Projection(Box::new(Projection {
+                base: place.clone(),
+                elem: ProjectionElem::Field(Field::new(0), self.ref_gen_ty),
+            }));
+        } else {
+            self.super_place(place, context, location);
+        }
+    }
+}
+
 fn self_arg() -> Local {
     Local::new(1)
 }
@@ -171,7 +198,7 @@ impl<'a, 'tcx> TransformVisitor<'a, 'tcx> {
             span: source_info.span,
             ty: self.tcx.types.u32,
             user_ty: None,
-            literal: self.tcx.intern_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bits(
+            literal: self.tcx.mk_lazy_const(ty::LazyConst::Evaluated(ty::Const::from_bits(
                 self.tcx,
                 state_disc.into(),
                 ty::ParamEnv::empty().and(self.tcx.types.u32)
@@ -286,6 +313,23 @@ fn make_generator_state_argument_indirect<'a, 'tcx>(
     DerefArgVisitor.visit_mir(mir);
 }
 
+fn make_generator_state_argument_pinned<'a, 'tcx>(
+                tcx: TyCtxt<'a, 'tcx, 'tcx>,
+                mir: &mut Mir<'tcx>) {
+    let ref_gen_ty = mir.local_decls.raw[1].ty;
+
+    let pin_did = tcx.lang_items().pin_type().unwrap();
+    let pin_adt_ref = tcx.adt_def(pin_did);
+    let substs = tcx.intern_substs(&[ref_gen_ty.into()]);
+    let pin_ref_gen_ty = tcx.mk_adt(pin_adt_ref, substs);
+
+    // Replace the by ref generator argument
+    mir.local_decls.raw[1].ty = pin_ref_gen_ty;
+
+    // Add the Pin field access to accesses of the generator state
+    PinArgVisitor { ref_gen_ty }.visit_mir(mir);
+}
+
 fn replace_result_variable<'tcx>(
     ret_ty: Ty<'tcx>,
     mir: &mut Mir<'tcx>,
@@ -332,14 +376,14 @@ impl<'tcx> Visitor<'tcx> for StorageIgnored {
 fn locals_live_across_suspend_points(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     mir: &Mir<'tcx>,
-    source: MirSource,
+    source: MirSource<'tcx>,
     movable: bool,
 ) -> (
     liveness::LiveVarSet<Local>,
     FxHashMap<BasicBlock, liveness::LiveVarSet<Local>>,
 ) {
     let dead_unwinds = BitSet::new_empty(mir.basic_blocks().len());
-    let node_id = tcx.hir().as_local_node_id(source.def_id).unwrap();
+    let node_id = tcx.hir().as_local_node_id(source.def_id()).unwrap();
 
     // Calculate when MIR locals have live storage. This gives us an upper bound of their
     // lifetimes.
@@ -440,7 +484,7 @@ fn locals_live_across_suspend_points(
 }
 
 fn compute_layout<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                            source: MirSource,
+                            source: MirSource<'tcx>,
                             upvars: Vec<Ty<'tcx>>,
                             interior: Ty<'tcx>,
                             movable: bool,
@@ -537,9 +581,9 @@ fn insert_switch<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 fn elaborate_generator_drops<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                        def_id: DefId,
                                        mir: &mut Mir<'tcx>) {
-    use util::elaborate_drops::{elaborate_drop, Unwind};
-    use util::patch::MirPatch;
-    use shim::DropShimElaborator;
+    use crate::util::elaborate_drops::{elaborate_drop, Unwind};
+    use crate::util::patch::MirPatch;
+    use crate::shim::DropShimElaborator;
 
     // Note that `elaborate_drops` only drops the upvars of a generator, and
     // this is ok because `open_drop` can only be reached within that own
@@ -591,7 +635,7 @@ fn create_generator_drop_shim<'a, 'tcx>(
                 tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 transform: &TransformVisitor<'a, 'tcx>,
                 def_id: DefId,
-                source: MirSource,
+                source: MirSource<'tcx>,
                 gen_ty: Ty<'tcx>,
                 mir: &Mir<'tcx>,
                 drop_clean: BasicBlock) -> Mir<'tcx> {
@@ -687,7 +731,7 @@ fn insert_panic_block<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             span: mir.span,
             ty: tcx.types.bool,
             user_ty: None,
-            literal: tcx.intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: tcx.mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::from_bool(tcx, false),
             )),
         }),
@@ -714,7 +758,7 @@ fn create_generator_resume_function<'a, 'tcx>(
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
         transform: TransformVisitor<'a, 'tcx>,
         def_id: DefId,
-        source: MirSource,
+        source: MirSource<'tcx>,
         mir: &mut Mir<'tcx>) {
     // Poison the generator when it unwinds
     for block in mir.basic_blocks_mut() {
@@ -741,6 +785,7 @@ fn create_generator_resume_function<'a, 'tcx>(
     insert_switch(tcx, mir, cases, &transform, TerminatorKind::Unreachable);
 
     make_generator_state_argument_indirect(tcx, def_id, mir);
+    make_generator_state_argument_pinned(tcx, mir);
 
     no_landing_pads(tcx, mir);
 
@@ -824,7 +869,7 @@ fn create_cases<'a, 'tcx, F>(mir: &mut Mir<'tcx>,
 impl MirPass for StateTransform {
     fn run_pass<'a, 'tcx>(&self,
                     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                    source: MirSource,
+                    source: MirSource<'tcx>,
                     mir: &mut Mir<'tcx>) {
         let yield_ty = if let Some(yield_ty) = mir.yield_ty {
             yield_ty
@@ -835,7 +880,7 @@ impl MirPass for StateTransform {
 
         assert!(mir.generator_drop.is_none());
 
-        let def_id = source.def_id;
+        let def_id = source.def_id();
 
         // The first argument is the generator type passed by value
         let gen_ty = mir.local_decls.raw[1].ty;
diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs
index 8b970c1408e37..07ebbf6d0ebe3 100644
--- a/src/librustc_mir/transform/inline.rs
+++ b/src/librustc_mir/transform/inline.rs
@@ -1,6 +1,5 @@
 //! Inlining pass for MIR functions
 
-use rustc::hir;
 use rustc::hir::CodegenFnAttrFlags;
 use rustc::hir::def_id::DefId;
 
@@ -14,10 +13,10 @@ use rustc::ty::subst::{Subst,Substs};
 
 use std::collections::VecDeque;
 use std::iter;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 use super::simplify::{remove_dead_blocks, CfgSimplifier};
 
-use syntax::{attr};
+use syntax::attr;
 use rustc_target::spec::abi::Abi;
 
 const DEFAULT_THRESHOLD: usize = 50;
@@ -41,7 +40,7 @@ struct CallSite<'tcx> {
 impl MirPass for Inline {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          source: MirSource,
+                          source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         if tcx.sess.opts.debugging_opts.mir_opt_level >= 2 {
             Inliner { tcx, source }.run_pass(mir);
@@ -51,7 +50,7 @@ impl MirPass for Inline {
 
 struct Inliner<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    source: MirSource,
+    source: MirSource<'tcx>,
 }
 
 impl<'a, 'tcx> Inliner<'a, 'tcx> {
@@ -70,19 +69,16 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
 
         let mut callsites = VecDeque::new();
 
-        let param_env = self.tcx.param_env(self.source.def_id);
+        let param_env = self.tcx.param_env(self.source.def_id());
 
         // Only do inlining into fn bodies.
-        let id = self.tcx.hir().as_local_node_id(self.source.def_id).unwrap();
-        let body_owner_kind = self.tcx.hir().body_owner_kind(id);
-
-        if let (hir::BodyOwnerKind::Fn, None) = (body_owner_kind, self.source.promoted) {
-
+        let id = self.tcx.hir().as_local_node_id(self.source.def_id()).unwrap();
+        if self.tcx.hir().body_owner_kind(id).is_fn_or_closure() && self.source.promoted.is_none() {
             for (bb, bb_data) in caller_mir.basic_blocks().iter_enumerated() {
                 if let Some(callsite) = self.get_valid_function_call(bb,
-                                                                     bb_data,
-                                                                     caller_mir,
-                                                                     param_env) {
+                                                                    bb_data,
+                                                                    caller_mir,
+                                                                    param_env) {
                     callsites.push_back(callsite);
                 }
             }
@@ -102,22 +98,34 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                     continue;
                 }
 
-                let callee_mir = match self.tcx.try_optimized_mir(callsite.location.span,
-                                                                  callsite.callee) {
-                    Ok(callee_mir) if self.consider_optimizing(callsite, callee_mir) => {
-                        self.tcx.subst_and_normalize_erasing_regions(
-                            &callsite.substs,
-                            param_env,
-                            callee_mir,
-                        )
+                let self_node_id = self.tcx.hir().as_local_node_id(self.source.def_id()).unwrap();
+                let callee_node_id = self.tcx.hir().as_local_node_id(callsite.callee);
+
+                let callee_mir = if let Some(callee_node_id) = callee_node_id {
+                    // Avoid a cycle here by only using `optimized_mir` only if we have
+                    // a lower node id than the callee. This ensures that the callee will
+                    // not inline us. This trick only works without incremental compilation.
+                    // So don't do it if that is enabled.
+                    if !self.tcx.dep_graph.is_fully_enabled()
+                        && self_node_id.as_u32() < callee_node_id.as_u32() {
+                        self.tcx.optimized_mir(callsite.callee)
+                    } else {
+                        continue;
                     }
-                    Ok(_) => continue,
+                } else {
+                    // This cannot result in a cycle since the callee MIR is from another crate
+                    // and is already optimized.
+                    self.tcx.optimized_mir(callsite.callee)
+                };
 
-                    Err(mut bug) => {
-                        // FIXME(#43542) shouldn't have to cancel an error
-                        bug.cancel();
-                        continue
-                    }
+                let callee_mir = if self.consider_optimizing(callsite, callee_mir) {
+                    self.tcx.subst_and_normalize_erasing_regions(
+                        &callsite.substs,
+                        param_env,
+                        callee_mir,
+                    )
+                } else {
+                    continue;
                 };
 
                 let start = caller_mir.basic_blocks().len();
@@ -278,7 +286,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
 
         // FIXME: Give a bonus to functions with only a single caller
 
-        let param_env = tcx.param_env(self.source.def_id);
+        let param_env = tcx.param_env(self.source.def_id());
 
         let mut first_block = true;
         let mut cost = 0;
@@ -430,7 +438,7 @@ impl<'a, 'tcx> Inliner<'a, 'tcx> {
                 // Place could result in two different locations if `f`
                 // writes to `i`. To prevent this we need to create a temporary
                 // borrow of the place and pass the destination as `*temp` instead.
-                fn dest_needs_borrow(place: &Place) -> bool {
+                fn dest_needs_borrow(place: &Place<'_>) -> bool {
                     match *place {
                         Place::Projection(ref p) => {
                             match p.elem {
diff --git a/src/librustc_mir/transform/instcombine.rs b/src/librustc_mir/transform/instcombine.rs
index 2b5e761d1d055..290915763e275 100644
--- a/src/librustc_mir/transform/instcombine.rs
+++ b/src/librustc_mir/transform/instcombine.rs
@@ -6,14 +6,14 @@ use rustc::ty::{TyCtxt, TyKind};
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
 use rustc_data_structures::indexed_vec::Idx;
 use std::mem;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct InstCombine;
 
 impl MirPass for InstCombine {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _: MirSource,
+                          _: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         // We only run when optimizing MIR (at any level).
         if tcx.sess.opts.debugging_opts.mir_opt_level == 0 {
diff --git a/src/librustc_mir/transform/lower_128bit.rs b/src/librustc_mir/transform/lower_128bit.rs
index d14e0f078e6c6..3d1f55e530e62 100644
--- a/src/librustc_mir/transform/lower_128bit.rs
+++ b/src/librustc_mir/transform/lower_128bit.rs
@@ -5,15 +5,14 @@ use rustc::middle::lang_items::LangItem;
 use rustc::mir::*;
 use rustc::ty::{List, Ty, TyCtxt, TyKind};
 use rustc_data_structures::indexed_vec::{Idx};
-use transform::{MirPass, MirSource};
-use syntax;
+use crate::transform::{MirPass, MirSource};
 
 pub struct Lower128Bit;
 
 impl MirPass for Lower128Bit {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let debugging_override = tcx.sess.opts.debugging_opts.lower_128bit_ops;
         let target_default = tcx.sess.host.options.i128_lowering;
@@ -182,7 +181,7 @@ impl RhsKind {
     }
 }
 
-fn sign_of_128bit(ty: Ty) -> Option<bool> {
+fn sign_of_128bit(ty: Ty<'_>) -> Option<bool> {
     match ty.sty {
         TyKind::Int(syntax::ast::IntTy::I128) => Some(true),
         TyKind::Uint(syntax::ast::UintTy::U128) => Some(false),
diff --git a/src/librustc_mir/transform/mod.rs b/src/librustc_mir/transform/mod.rs
index 5a80a5fdab501..28b9e082851c0 100644
--- a/src/librustc_mir/transform/mod.rs
+++ b/src/librustc_mir/transform/mod.rs
@@ -1,8 +1,8 @@
-use borrow_check::nll::type_check;
-use build;
+use crate::borrow_check::nll::type_check;
+use crate::build;
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc::mir::{Mir, MirPhase, Promoted};
-use rustc::ty::TyCtxt;
+use rustc::ty::{TyCtxt, InstanceDef};
 use rustc::ty::query::Providers;
 use rustc::ty::steal::Steal;
 use rustc::hir;
@@ -38,7 +38,7 @@ pub mod inline;
 pub mod lower_128bit;
 pub mod uniform_array_move_out;
 
-pub(crate) fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers<'_>) {
     self::qualify_consts::provide(providers);
     self::check_unsafety::provide(providers);
     *providers = Providers {
@@ -56,7 +56,7 @@ fn is_mir_available<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> boo
     tcx.mir_keys(def_id.krate).contains(&def_id)
 }
 
-/// Finds the full set of def-ids within the current crate that have
+/// Finds the full set of `DefId`s within the current crate that have
 /// MIR associated with them.
 fn mir_keys<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, krate: CrateNum)
                       -> Lrc<DefIdSet> {
@@ -80,7 +80,7 @@ fn mir_keys<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, krate: CrateNum)
                               _: &'tcx hir::Generics,
                               _: ast::NodeId,
                               _: Span) {
-            if let hir::VariantData::Tuple(_, node_id) = *v {
+            if let hir::VariantData::Tuple(_, node_id, _) = *v {
                 self.set.insert(self.tcx.hir().local_def_id(node_id));
             }
             intravisit::walk_struct_def(self, v)
@@ -104,20 +104,25 @@ fn mir_built<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Stea
 
 /// Where a specific Mir comes from.
 #[derive(Debug, Copy, Clone)]
-pub struct MirSource {
-    pub def_id: DefId,
+pub struct MirSource<'tcx> {
+    pub instance: InstanceDef<'tcx>,
 
     /// If `Some`, this is a promoted rvalue within the parent function.
     pub promoted: Option<Promoted>,
 }
 
-impl MirSource {
+impl<'tcx> MirSource<'tcx> {
     pub fn item(def_id: DefId) -> Self {
         MirSource {
-            def_id,
+            instance: InstanceDef::Item(def_id),
             promoted: None
         }
     }
+
+    #[inline]
+    pub fn def_id(&self) -> DefId {
+        self.instance.def_id()
+    }
 }
 
 /// Generates a default name for the pass based on the name of the
@@ -141,14 +146,14 @@ pub trait MirPass {
 
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          source: MirSource,
+                          source: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>);
 }
 
 pub fn run_passes(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     mir: &mut Mir<'tcx>,
-    def_id: DefId,
+    instance: InstanceDef<'tcx>,
     mir_phase: MirPhase,
     passes: &[&dyn MirPass],
 ) {
@@ -160,7 +165,7 @@ pub fn run_passes(
         }
 
         let source = MirSource {
-            def_id,
+            instance,
             promoted,
         };
         let mut index = 0;
@@ -198,7 +203,7 @@ fn mir_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Stea
     let _ = tcx.unsafety_check_result(def_id);
 
     let mut mir = tcx.mir_built(def_id).steal();
-    run_passes(tcx, &mut mir, def_id, MirPhase::Const, &[
+    run_passes(tcx, &mut mir, InstanceDef::Item(def_id), MirPhase::Const, &[
         // What we need to do constant evaluation.
         &simplify::SimplifyCfg::new("initial"),
         &type_check::TypeckMir,
@@ -217,7 +222,7 @@ fn mir_validated<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx
     }
 
     let mut mir = tcx.mir_const(def_id).steal();
-    run_passes(tcx, &mut mir, def_id, MirPhase::Validated, &[
+    run_passes(tcx, &mut mir, InstanceDef::Item(def_id), MirPhase::Validated, &[
         // What we need to run borrowck etc.
         &qualify_consts::QualifyAndPromoteConstants,
         &simplify::SimplifyCfg::new("qualify-consts"),
@@ -228,14 +233,14 @@ fn mir_validated<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx
 fn optimized_mir<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx Mir<'tcx> {
     // (Mir-)Borrowck uses `mir_validated`, so we have to force it to
     // execute before we can steal.
-    let _ = tcx.mir_borrowck(def_id);
+    tcx.ensure().mir_borrowck(def_id);
 
     if tcx.use_ast_borrowck() {
-        let _ = tcx.borrowck(def_id);
+        tcx.ensure().borrowck(def_id);
     }
 
     let mut mir = tcx.mir_validated(def_id).steal();
-    run_passes(tcx, &mut mir, def_id, MirPhase::Optimized, &[
+    run_passes(tcx, &mut mir, InstanceDef::Item(def_id), MirPhase::Optimized, &[
         // Remove all things not needed by analysis
         &no_landing_pads::NoLandingPads,
         &simplify_branches::SimplifyBranches::new("initial"),
diff --git a/src/librustc_mir/transform/no_landing_pads.rs b/src/librustc_mir/transform/no_landing_pads.rs
index 2d13b066270a2..089d9b9b54454 100644
--- a/src/librustc_mir/transform/no_landing_pads.rs
+++ b/src/librustc_mir/transform/no_landing_pads.rs
@@ -4,14 +4,14 @@
 use rustc::ty::TyCtxt;
 use rustc::mir::*;
 use rustc::mir::visit::MutVisitor;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct NoLandingPads;
 
 impl MirPass for NoLandingPads {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _: MirSource,
+                          _: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         no_landing_pads(tcx, mir)
     }
diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index 1602fc35a2c95..a6726718e2d23 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -130,7 +130,8 @@ impl<'tcx> Visitor<'tcx> for TempCollector<'tcx> {
     }
 }
 
-pub fn collect_temps(mir: &Mir, rpo: &mut ReversePostorder) -> IndexVec<Local, TempState> {
+pub fn collect_temps(mir: &Mir<'_>,
+                     rpo: &mut ReversePostorder<'_, '_>) -> IndexVec<Local, TempState> {
     let mut collector = TempCollector {
         temps: IndexVec::from_elem(TempState::Undefined, &mir.local_decls),
         span: mir.span,
@@ -181,7 +182,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
         });
     }
 
-    /// Copy the initialization of this temp to the
+    /// Copies the initialization of this temp to the
     /// promoted MIR, recursing through temps.
     fn promote_temp(&mut self, temp: Local) -> Local {
         let old_keep_original = self.keep_original;
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 78cf7153500c9..285c674643f2e 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -21,58 +21,16 @@ use rustc::mir::visit::{PlaceContext, Visitor, MutatingUseContext, NonMutatingUs
 use rustc::middle::lang_items;
 use rustc::session::config::nightly_options;
 use syntax::ast::LitKind;
-use syntax::feature_gate::{UnstableFeatures, emit_feature_err, GateIssue};
+use syntax::feature_gate::{emit_feature_err, GateIssue};
 use syntax_pos::{Span, DUMMY_SP};
 
 use std::fmt;
+use std::ops::{Deref, Index, IndexMut};
 use std::usize;
 
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 use super::promote_consts::{self, Candidate, TempState};
 
-bitflags! {
-    // Borrows of temporaries can be promoted only if
-    // they have none of these qualifications, with
-    // the exception of `STATIC_REF` (in statics only).
-    struct Qualif: u8 {
-        // Constant containing interior mutability (UnsafeCell).
-        const MUTABLE_INTERIOR  = 1 << 0;
-
-        // Constant containing an ADT that implements Drop.
-        const NEEDS_DROP        = 1 << 1;
-
-        // Function argument.
-        const FN_ARGUMENT       = 1 << 2;
-
-        // Not constant at all - non-`const fn` calls, asm!,
-        // pointer comparisons, ptr-to-int casts, etc.
-        const NOT_CONST         = 1 << 3;
-
-        // Refers to temporaries which cannot be promoted as
-        // promote_consts decided they weren't simple enough.
-        const NOT_PROMOTABLE    = 1 << 4;
-
-        // Const items can only have MUTABLE_INTERIOR
-        // and NOT_PROMOTABLE without producing an error.
-        const CONST_ERROR       = !Qualif::MUTABLE_INTERIOR.bits &
-                                  !Qualif::NOT_PROMOTABLE.bits;
-    }
-}
-
-impl<'a, 'tcx> Qualif {
-    /// Remove flags which are impossible for the given type.
-    fn restrict(&mut self, ty: Ty<'tcx>,
-                tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                param_env: ty::ParamEnv<'tcx>) {
-        if ty.is_freeze(tcx, param_env, DUMMY_SP) {
-            *self = *self - Qualif::MUTABLE_INTERIOR;
-        }
-        if !ty.needs_drop(tcx, param_env) {
-            *self = *self - Qualif::NEEDS_DROP;
-        }
-    }
-}
-
 /// What kind of item we are in.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 enum Mode {
@@ -84,7 +42,7 @@ enum Mode {
 }
 
 impl fmt::Display for Mode {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Mode::Const => write!(f, "constant"),
             Mode::Static | Mode::StaticMut => write!(f, "static"),
@@ -94,26 +52,559 @@ impl fmt::Display for Mode {
     }
 }
 
-struct Qualifier<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
+const QUALIF_COUNT: usize = 4;
+
+// FIXME(eddyb) once we can use const generics, replace this array with
+// something like `IndexVec` but for fixed-size arrays (`IndexArray`?).
+#[derive(Copy, Clone, Default)]
+struct PerQualif<T>([T; QUALIF_COUNT]);
+
+impl<T: Clone> PerQualif<T> {
+    fn new(x: T) -> Self {
+        PerQualif([x.clone(), x.clone(), x.clone(), x])
+    }
+}
+
+impl<T> PerQualif<T> {
+    fn as_mut(&mut self) -> PerQualif<&mut T> {
+        let [x0, x1, x2, x3] = &mut self.0;
+        PerQualif([x0, x1, x2, x3])
+    }
+
+    fn zip<U>(self, other: PerQualif<U>) -> PerQualif<(T, U)> {
+        let [x0, x1, x2, x3] = self.0;
+        let [y0, y1, y2, y3] = other.0;
+        PerQualif([(x0, y0), (x1, y1), (x2, y2), (x3, y3)])
+    }
+}
+
+impl PerQualif<bool> {
+    fn encode_to_bits(self) -> u8 {
+        self.0.iter().enumerate().fold(0, |bits, (i, &qualif)| {
+            bits | ((qualif as u8) << i)
+        })
+    }
+
+    fn decode_from_bits(bits: u8) -> Self {
+        let mut qualifs = Self::default();
+        for (i, qualif) in qualifs.0.iter_mut().enumerate() {
+            *qualif = (bits & (1 << i)) != 0;
+        }
+        qualifs
+    }
+}
+
+impl<Q: Qualif, T> Index<Q> for PerQualif<T> {
+    type Output = T;
+
+    fn index(&self, _: Q) -> &T {
+        &self.0[Q::IDX]
+    }
+}
+
+impl<Q: Qualif, T> IndexMut<Q> for PerQualif<T> {
+    fn index_mut(&mut self, _: Q) -> &mut T {
+        &mut self.0[Q::IDX]
+    }
+}
+
+struct ConstCx<'a, 'tcx> {
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
     mode: Mode,
+    mir: &'a Mir<'tcx>,
+
+    per_local: PerQualif<BitSet<Local>>,
+}
+
+impl<'a, 'tcx> ConstCx<'a, 'tcx> {
+    fn is_const_panic_fn(&self, def_id: DefId) -> bool {
+        Some(def_id) == self.tcx.lang_items().panic_fn() ||
+        Some(def_id) == self.tcx.lang_items().begin_panic_fn()
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+enum ValueSource<'a, 'tcx> {
+    Rvalue(&'a Rvalue<'tcx>),
+    Call {
+        callee: &'a Operand<'tcx>,
+        args: &'a [Operand<'tcx>],
+        return_ty: Ty<'tcx>,
+    },
+}
+
+trait Qualif {
+    const IDX: usize;
+
+    /// Return the qualification that is (conservatively) correct for any value
+    /// of the type, or `None` if the qualification is not value/type-based.
+    fn in_any_value_of_ty(_cx: &ConstCx<'_, 'tcx>, _ty: Ty<'tcx>) -> Option<bool> {
+        None
+    }
+
+    /// Return a mask for the qualification, given a type. This is `false` iff
+    /// no value of that type can have the qualification.
+    fn mask_for_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> bool {
+        Self::in_any_value_of_ty(cx, ty).unwrap_or(true)
+    }
+
+    fn in_local(cx: &ConstCx<'_, '_>, local: Local) -> bool {
+        cx.per_local.0[Self::IDX].contains(local)
+    }
+
+    fn in_static(_cx: &ConstCx<'_, 'tcx>, _static: &Static<'tcx>) -> bool {
+        // FIXME(eddyb) should we do anything here for value properties?
+        false
+    }
+
+    fn in_projection_structurally(
+        cx: &ConstCx<'_, 'tcx>,
+        proj: &PlaceProjection<'tcx>,
+    ) -> bool {
+        let base_qualif = Self::in_place(cx, &proj.base);
+        let qualif = base_qualif && Self::mask_for_ty(
+            cx,
+            proj.base.ty(cx.mir, cx.tcx)
+                .projection_ty(cx.tcx, &proj.elem)
+                .to_ty(cx.tcx),
+        );
+        match proj.elem {
+            ProjectionElem::Deref |
+            ProjectionElem::Subslice { .. } |
+            ProjectionElem::Field(..) |
+            ProjectionElem::ConstantIndex { .. } |
+            ProjectionElem::Downcast(..) => qualif,
+
+            ProjectionElem::Index(local) => qualif || Self::in_local(cx, local),
+        }
+    }
+
+    fn in_projection(cx: &ConstCx<'_, 'tcx>, proj: &PlaceProjection<'tcx>) -> bool {
+        Self::in_projection_structurally(cx, proj)
+    }
+
+    fn in_place(cx: &ConstCx<'_, 'tcx>, place: &Place<'tcx>) -> bool {
+        match *place {
+            Place::Local(local) => Self::in_local(cx, local),
+            Place::Promoted(_) => bug!("qualifying already promoted MIR"),
+            Place::Static(ref static_) => Self::in_static(cx, static_),
+            Place::Projection(ref proj) => Self::in_projection(cx, proj),
+        }
+    }
+
+    fn in_operand(cx: &ConstCx<'_, 'tcx>, operand: &Operand<'tcx>) -> bool {
+        match *operand {
+            Operand::Copy(ref place) |
+            Operand::Move(ref place) => Self::in_place(cx, place),
+
+            Operand::Constant(ref constant) => {
+                if let ty::LazyConst::Unevaluated(def_id, _) = constant.literal {
+                    // Don't peek inside trait associated constants.
+                    if cx.tcx.trait_of_item(*def_id).is_some() {
+                        Self::in_any_value_of_ty(cx, constant.ty).unwrap_or(false)
+                    } else {
+                        let (bits, _) = cx.tcx.at(constant.span).mir_const_qualif(*def_id);
+
+                        let qualif = PerQualif::decode_from_bits(bits).0[Self::IDX];
+
+                        // Just in case the type is more specific than
+                        // the definition, e.g., impl associated const
+                        // with type parameters, take it into account.
+                        qualif && Self::mask_for_ty(cx, constant.ty)
+                    }
+                } else {
+                    false
+                }
+            }
+        }
+    }
+
+    fn in_rvalue_structurally(cx: &ConstCx<'_, 'tcx>, rvalue: &Rvalue<'tcx>) -> bool {
+        match *rvalue {
+            Rvalue::NullaryOp(..) => false,
+
+            Rvalue::Discriminant(ref place) |
+            Rvalue::Len(ref place) => Self::in_place(cx, place),
+
+            Rvalue::Use(ref operand) |
+            Rvalue::Repeat(ref operand, _) |
+            Rvalue::UnaryOp(_, ref operand) |
+            Rvalue::Cast(_, ref operand, _) => Self::in_operand(cx, operand),
+
+            Rvalue::BinaryOp(_, ref lhs, ref rhs) |
+            Rvalue::CheckedBinaryOp(_, ref lhs, ref rhs) => {
+                Self::in_operand(cx, lhs) || Self::in_operand(cx, rhs)
+            }
+
+            Rvalue::Ref(_, _, ref place) => {
+                // Special-case reborrows to be more like a copy of the reference.
+                if let Place::Projection(ref proj) = *place {
+                    if let ProjectionElem::Deref = proj.elem {
+                        let base_ty = proj.base.ty(cx.mir, cx.tcx).to_ty(cx.tcx);
+                        if let ty::Ref(..) = base_ty.sty {
+                            return Self::in_place(cx, &proj.base);
+                        }
+                    }
+                }
+
+                Self::in_place(cx, place)
+            }
+
+            Rvalue::Aggregate(_, ref operands) => {
+                operands.iter().any(|o| Self::in_operand(cx, o))
+            }
+        }
+    }
+
+    fn in_rvalue(cx: &ConstCx<'_, 'tcx>, rvalue: &Rvalue<'tcx>) -> bool {
+        Self::in_rvalue_structurally(cx, rvalue)
+    }
+
+    fn in_call(
+        cx: &ConstCx<'_, 'tcx>,
+        _callee: &Operand<'tcx>,
+        _args: &[Operand<'tcx>],
+        return_ty: Ty<'tcx>,
+    ) -> bool {
+        // Be conservative about the returned value of a const fn.
+        Self::in_any_value_of_ty(cx, return_ty).unwrap_or(false)
+    }
+
+    fn in_value(cx: &ConstCx<'_, 'tcx>, source: ValueSource<'_, 'tcx>) -> bool {
+        match source {
+            ValueSource::Rvalue(rvalue) => Self::in_rvalue(cx, rvalue),
+            ValueSource::Call { callee, args, return_ty } => {
+                Self::in_call(cx, callee, args, return_ty)
+            }
+        }
+    }
+}
+
+// Constant containing interior mutability (UnsafeCell).
+struct HasMutInterior;
+
+impl Qualif for HasMutInterior {
+    const IDX: usize = 0;
+
+    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> Option<bool> {
+        Some(!ty.is_freeze(cx.tcx, cx.param_env, DUMMY_SP))
+    }
+
+    fn in_rvalue(cx: &ConstCx<'_, 'tcx>, rvalue: &Rvalue<'tcx>) -> bool {
+        match *rvalue {
+            // Returning `true` for `Rvalue::Ref` indicates the borrow isn't
+            // allowed in constants (and the `Checker` will error), and/or it
+            // won't be promoted, due to `&mut ...` or interior mutability.
+            Rvalue::Ref(_, kind, ref place) => {
+                let ty = place.ty(cx.mir, cx.tcx).to_ty(cx.tcx);
+
+                if let BorrowKind::Mut { .. } = kind {
+                    // In theory, any zero-sized value could be borrowed
+                    // mutably without consequences. However, only &mut []
+                    // is allowed right now, and only in functions.
+                    if cx.mode == Mode::StaticMut {
+                        // Inside a `static mut`, &mut [...] is also allowed.
+                        match ty.sty {
+                            ty::Array(..) | ty::Slice(_) => {}
+                            _ => return true,
+                        }
+                    } else if let ty::Array(_, len) = ty.sty {
+                        // FIXME(eddyb) the `cx.mode == Mode::Fn` condition
+                        // seems unnecessary, given that this is merely a ZST.
+                        if !(len.unwrap_usize(cx.tcx) == 0 && cx.mode == Mode::Fn) {
+                            return true;
+                        }
+                    } else {
+                        return true;
+                    }
+                }
+            }
+
+            Rvalue::Aggregate(ref kind, _) => {
+                if let AggregateKind::Adt(def, ..) = **kind {
+                    if Some(def.did) == cx.tcx.lang_items().unsafe_cell_type() {
+                        let ty = rvalue.ty(cx.mir, cx.tcx);
+                        assert_eq!(Self::in_any_value_of_ty(cx, ty), Some(true));
+                        return true;
+                    }
+                }
+            }
+
+            _ => {}
+        }
+
+        Self::in_rvalue_structurally(cx, rvalue)
+    }
+}
+
+// Constant containing an ADT that implements Drop.
+struct NeedsDrop;
+
+impl Qualif for NeedsDrop {
+    const IDX: usize = 1;
+
+    fn in_any_value_of_ty(cx: &ConstCx<'_, 'tcx>, ty: Ty<'tcx>) -> Option<bool> {
+        Some(ty.needs_drop(cx.tcx, cx.param_env))
+    }
+
+    fn in_rvalue(cx: &ConstCx<'_, 'tcx>, rvalue: &Rvalue<'tcx>) -> bool {
+        if let Rvalue::Aggregate(ref kind, _) = *rvalue {
+            if let AggregateKind::Adt(def, ..) = **kind {
+                if def.has_dtor(cx.tcx) {
+                    return true;
+                }
+            }
+        }
+
+        Self::in_rvalue_structurally(cx, rvalue)
+    }
+}
+
+// Not constant at all - non-`const fn` calls, asm!,
+// pointer comparisons, ptr-to-int casts, etc.
+struct IsNotConst;
+
+impl Qualif for IsNotConst {
+    const IDX: usize = 2;
+
+    fn in_static(cx: &ConstCx<'_, 'tcx>, static_: &Static<'tcx>) -> bool {
+        // Only allow statics (not consts) to refer to other statics.
+        let allowed = cx.mode == Mode::Static || cx.mode == Mode::StaticMut;
+
+        !allowed ||
+            cx.tcx.get_attrs(static_.def_id).iter().any(|attr| attr.check_name("thread_local"))
+    }
+
+    fn in_projection(cx: &ConstCx<'_, 'tcx>, proj: &PlaceProjection<'tcx>) -> bool {
+        match proj.elem {
+            ProjectionElem::Deref |
+            ProjectionElem::Downcast(..) => return true,
+
+            ProjectionElem::ConstantIndex {..} |
+            ProjectionElem::Subslice {..} |
+            ProjectionElem::Index(_) => {}
+
+            ProjectionElem::Field(..) => {
+                if cx.mode == Mode::Fn {
+                    let base_ty = proj.base.ty(cx.mir, cx.tcx).to_ty(cx.tcx);
+                    if let Some(def) = base_ty.ty_adt_def() {
+                        if def.is_union() {
+                            return true;
+                        }
+                    }
+                }
+            }
+        }
+
+        Self::in_projection_structurally(cx, proj)
+    }
+
+    fn in_rvalue(cx: &ConstCx<'_, 'tcx>, rvalue: &Rvalue<'tcx>) -> bool {
+        match *rvalue {
+            Rvalue::Cast(CastKind::Misc, ref operand, cast_ty) if cx.mode == Mode::Fn => {
+                let operand_ty = operand.ty(cx.mir, cx.tcx);
+                let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast");
+                let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
+                match (cast_in, cast_out) {
+                    (CastTy::Ptr(_), CastTy::Int(_)) |
+                    (CastTy::FnPtr, CastTy::Int(_)) => {
+                        // in normal functions, mark such casts as not promotable
+                        return true;
+                    }
+                    _ => {}
+                }
+            }
+
+            Rvalue::BinaryOp(op, ref lhs, _) if cx.mode == Mode::Fn => {
+                if let ty::RawPtr(_) | ty::FnPtr(..) = lhs.ty(cx.mir, cx.tcx).sty {
+                    assert!(op == BinOp::Eq || op == BinOp::Ne ||
+                            op == BinOp::Le || op == BinOp::Lt ||
+                            op == BinOp::Ge || op == BinOp::Gt ||
+                            op == BinOp::Offset);
+
+                    // raw pointer operations are not allowed inside promoteds
+                    return true;
+                }
+            }
+
+            Rvalue::NullaryOp(NullOp::Box, _) => return true,
+
+            _ => {}
+        }
+
+        Self::in_rvalue_structurally(cx, rvalue)
+    }
+
+    fn in_call(
+        cx: &ConstCx<'_, 'tcx>,
+        callee: &Operand<'tcx>,
+        args: &[Operand<'tcx>],
+        _return_ty: Ty<'tcx>,
+    ) -> bool {
+        let fn_ty = callee.ty(cx.mir, cx.tcx);
+        match fn_ty.sty {
+            ty::FnDef(def_id, _) => {
+                match cx.tcx.fn_sig(def_id).abi() {
+                    Abi::RustIntrinsic |
+                    Abi::PlatformIntrinsic => {
+                        assert!(!cx.tcx.is_const_fn(def_id));
+                        match &cx.tcx.item_name(def_id).as_str()[..] {
+                            | "size_of"
+                            | "min_align_of"
+                            | "needs_drop"
+                            | "type_id"
+                            | "bswap"
+                            | "bitreverse"
+                            | "ctpop"
+                            | "cttz"
+                            | "cttz_nonzero"
+                            | "ctlz"
+                            | "ctlz_nonzero"
+                            | "overflowing_add"
+                            | "overflowing_sub"
+                            | "overflowing_mul"
+                            | "unchecked_shl"
+                            | "unchecked_shr"
+                            | "rotate_left"
+                            | "rotate_right"
+                            | "add_with_overflow"
+                            | "sub_with_overflow"
+                            | "mul_with_overflow"
+                            | "saturating_add"
+                            | "saturating_sub"
+                            | "transmute"
+                            => return true,
+
+                            _ => {}
+                        }
+                    }
+                    _ => {
+                        let is_const_fn =
+                            cx.tcx.is_const_fn(def_id) ||
+                            cx.tcx.is_unstable_const_fn(def_id).is_some() ||
+                            cx.is_const_panic_fn(def_id);
+                        if !is_const_fn {
+                            return true;
+                        }
+                    }
+                }
+            }
+            _ => return true,
+        }
+
+        Self::in_operand(cx, callee) || args.iter().any(|arg| Self::in_operand(cx, arg))
+    }
+}
+
+// Refers to temporaries which cannot be promoted as
+// promote_consts decided they weren't simple enough.
+struct IsNotPromotable;
+
+impl Qualif for IsNotPromotable {
+    const IDX: usize = 3;
+
+    fn in_call(
+        cx: &ConstCx<'_, 'tcx>,
+        callee: &Operand<'tcx>,
+        _args: &[Operand<'tcx>],
+        _return_ty: Ty<'tcx>,
+    ) -> bool {
+        if cx.mode == Mode::Fn {
+            if let ty::FnDef(def_id, _) = callee.ty(cx.mir, cx.tcx).sty {
+                // Never promote runtime `const fn` calls of
+                // functions without `#[rustc_promotable]`.
+                if !cx.tcx.is_promotable_const_fn(def_id) {
+                    return true;
+                }
+            }
+        }
+
+        // FIXME(eddyb) do we need "not promotable" in anything
+        // other than `Mode::Fn` by any chance?
+
+        false
+    }
+}
+
+// Ensure the `IDX` values are sequential (`0..QUALIF_COUNT`).
+macro_rules! static_assert_seq_qualifs {
+    ($i:expr => $first:ident $(, $rest:ident)*) => {
+        static_assert!(SEQ_QUALIFS: {
+            static_assert_seq_qualifs!($i + 1 => $($rest),*);
+
+            $first::IDX == $i
+        });
+    };
+    ($i:expr =>) => {
+        static_assert!(SEQ_QUALIFS: QUALIF_COUNT == $i);
+    };
+}
+static_assert_seq_qualifs!(0 => HasMutInterior, NeedsDrop, IsNotConst, IsNotPromotable);
+
+impl ConstCx<'_, 'tcx> {
+    fn qualifs_in_any_value_of_ty(&self, ty: Ty<'tcx>) -> PerQualif<bool> {
+        let mut qualifs = PerQualif::default();
+        qualifs[HasMutInterior] = HasMutInterior::in_any_value_of_ty(self, ty).unwrap_or(false);
+        qualifs[NeedsDrop] = NeedsDrop::in_any_value_of_ty(self, ty).unwrap_or(false);
+        qualifs[IsNotConst] = IsNotConst::in_any_value_of_ty(self, ty).unwrap_or(false);
+        qualifs[IsNotPromotable] = IsNotPromotable::in_any_value_of_ty(self, ty).unwrap_or(false);
+        qualifs
+    }
+
+    fn qualifs_in_local(&self, local: Local) -> PerQualif<bool> {
+        let mut qualifs = PerQualif::default();
+        qualifs[HasMutInterior] = HasMutInterior::in_local(self, local);
+        qualifs[NeedsDrop] = NeedsDrop::in_local(self, local);
+        qualifs[IsNotConst] = IsNotConst::in_local(self, local);
+        qualifs[IsNotPromotable] = IsNotPromotable::in_local(self, local);
+        qualifs
+    }
+
+    fn qualifs_in_value(&self, source: ValueSource<'_, 'tcx>) -> PerQualif<bool> {
+        let mut qualifs = PerQualif::default();
+        qualifs[HasMutInterior] = HasMutInterior::in_value(self, source);
+        qualifs[NeedsDrop] = NeedsDrop::in_value(self, source);
+        qualifs[IsNotConst] = IsNotConst::in_value(self, source);
+        qualifs[IsNotPromotable] = IsNotPromotable::in_value(self, source);
+        qualifs
+    }
+}
+
+struct Checker<'a, 'tcx> {
+    cx: ConstCx<'a, 'tcx>,
+
     span: Span,
     def_id: DefId,
-    mir: &'a Mir<'tcx>,
     rpo: ReversePostorder<'a, 'tcx>,
-    tcx: TyCtxt<'a, 'gcx, 'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
-    local_qualif: IndexVec<Local, Option<Qualif>>,
-    qualif: Qualif,
+
     temp_promotion_state: IndexVec<Local, TempState>,
-    promotion_candidates: Vec<Candidate>
+    promotion_candidates: Vec<Candidate>,
+}
+
+macro_rules! unleash_miri {
+    ($this:expr) => {{
+        if $this.tcx.sess.opts.debugging_opts.unleash_the_miri_inside_of_you {
+            $this.tcx.sess.span_warn($this.span, "skipping const checks");
+            return;
+        }
+    }}
 }
 
-impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
+impl Deref for Checker<'a, 'tcx> {
+    type Target = ConstCx<'a, 'tcx>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.cx
+    }
+}
+
+impl<'a, 'tcx> Checker<'a, 'tcx> {
     fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>,
            def_id: DefId,
            mir: &'a Mir<'tcx>,
            mode: Mode)
-           -> Qualifier<'a, 'tcx, 'tcx> {
+           -> Self {
         assert!(def_id.is_local());
         let mut rpo = traversal::reverse_postorder(mir);
         let temps = promote_consts::collect_temps(mir, &mut rpo);
@@ -121,23 +612,43 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
 
         let param_env = tcx.param_env(def_id);
 
-        let mut local_qualif = IndexVec::from_elem(None, &mir.local_decls);
-        for arg in mir.args_iter() {
-            let mut qualif = Qualif::NEEDS_DROP;
-            qualif.restrict(mir.local_decls[arg].ty, tcx, param_env);
-            local_qualif[arg] = Some(qualif);
+        let mut cx = ConstCx {
+            tcx,
+            param_env,
+            mode,
+            mir,
+            per_local: PerQualif::new(BitSet::new_empty(mir.local_decls.len())),
+        };
+
+        for (local, decl) in mir.local_decls.iter_enumerated() {
+            match mir.local_kind(local) {
+                LocalKind::Arg => {
+                    let qualifs = cx.qualifs_in_any_value_of_ty(decl.ty);
+                    for (per_local, qualif) in &mut cx.per_local.as_mut().zip(qualifs).0 {
+                        if *qualif {
+                            per_local.insert(local);
+                        }
+                    }
+                    cx.per_local[IsNotPromotable].insert(local);
+                }
+
+                LocalKind::Var if mode == Mode::Fn => {
+                    cx.per_local[IsNotConst].insert(local);
+                }
+
+                LocalKind::Temp if !temps[local].is_promotable() => {
+                    cx.per_local[IsNotPromotable].insert(local);
+                }
+
+                _ => {}
+            }
         }
 
-        Qualifier {
-            mode,
+        Checker {
+            cx,
             span: mir.span,
             def_id,
-            mir,
             rpo,
-            tcx,
-            param_env,
-            local_qualif,
-            qualif: Qualif::empty(),
             temp_promotion_state: temps,
             promotion_candidates: vec![]
         }
@@ -147,7 +658,7 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
     // categories, but enabling full miri would make that
     // slightly pointless (even with feature-gating).
     fn not_const(&mut self) {
-        self.add(Qualif::NOT_CONST);
+        unleash_miri!(self);
         if self.mode != Mode::Fn {
             let mut err = struct_span_err!(
                 self.tcx.sess,
@@ -166,49 +677,77 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
         }
     }
 
-    /// Add the given qualification to self.qualif.
-    fn add(&mut self, qualif: Qualif) {
-        self.qualif = self.qualif | qualif;
-    }
+    /// Assigns an rvalue/call qualification to the given destination.
+    fn assign(&mut self, dest: &Place<'tcx>, source: ValueSource<'_, 'tcx>, location: Location) {
+        trace!("assign: {:?} <- {:?}", dest, source);
 
-    /// Add the given type's qualification to self.qualif.
-    fn add_type(&mut self, ty: Ty<'tcx>) {
-        self.add(Qualif::MUTABLE_INTERIOR | Qualif::NEEDS_DROP);
-        self.qualif.restrict(ty, self.tcx, self.param_env);
-    }
+        let mut qualifs = self.qualifs_in_value(source);
 
-    /// Within the provided closure, self.qualif will start
-    /// out empty, and its value after the closure returns will
-    /// be combined with the value before the call to nest.
-    fn nest<F: FnOnce(&mut Self)>(&mut self, f: F) {
-        let original = self.qualif;
-        self.qualif = Qualif::empty();
-        f(self);
-        self.add(original);
-    }
+        if let ValueSource::Rvalue(&Rvalue::Ref(_, kind, ref place)) = source {
+            // Getting `true` from `HasMutInterior::in_rvalue` means
+            // the borrowed place is disallowed from being borrowed,
+            // due to either a mutable borrow (with some exceptions),
+            // or an shared borrow of a value with interior mutability.
+            // Then `HasMutInterior` is replaced with `IsNotConst`,
+            // to avoid duplicate errors (e.g. from reborrowing).
+            if qualifs[HasMutInterior] {
+                qualifs[HasMutInterior] = false;
+                qualifs[IsNotConst] = true;
 
-    /// Assign the current qualification to the given destination.
-    fn assign(&mut self, dest: &Place<'tcx>, location: Location) {
-        trace!("assign: {:?}", dest);
-        let qualif = self.qualif;
-        let span = self.span;
-        let store = |slot: &mut Option<Qualif>| {
-            if slot.is_some() {
-                span_bug!(span, "multiple assignments to {:?}", dest);
-            }
-            *slot = Some(qualif);
-        };
-
-        // Only handle promotable temps in non-const functions.
-        if self.mode == Mode::Fn {
-            if let Place::Local(index) = *dest {
-                if self.mir.local_kind(index) == LocalKind::Temp
-                && self.temp_promotion_state[index].is_promotable() {
-                    debug!("store to promotable temp {:?} ({:?})", index, qualif);
-                    store(&mut self.local_qualif[index]);
+                if self.mode != Mode::Fn {
+                    if let BorrowKind::Mut { .. } = kind {
+                        let mut err = struct_span_err!(self.tcx.sess,  self.span, E0017,
+                                                       "references in {}s may only refer \
+                                                        to immutable values", self.mode);
+                        err.span_label(self.span, format!("{}s require immutable values",
+                                                            self.mode));
+                        if self.tcx.sess.teach(&err.get_code().unwrap()) {
+                            err.note("References in statics and constants may only refer to \
+                                      immutable values.\n\n\
+                                      Statics are shared everywhere, and if they refer to \
+                                      mutable data one might violate memory safety since \
+                                      holding multiple mutable references to shared data is \
+                                      not allowed.\n\n\
+                                      If you really want global mutable state, try using \
+                                      static mut or a global UnsafeCell.");
+                        }
+                        err.emit();
+                    } else {
+                        span_err!(self.tcx.sess, self.span, E0492,
+                                  "cannot borrow a constant which may contain \
+                                   interior mutability, create a static instead");
+                    }
+                }
+            } else {
+                // We might have a candidate for promotion.
+                let candidate = Candidate::Ref(location);
+                // We can only promote interior borrows of promotable temps.
+                let mut place = place;
+                while let Place::Projection(ref proj) = *place {
+                    if proj.elem == ProjectionElem::Deref {
+                        break;
+                    }
+                    place = &proj.base;
+                }
+                debug!("qualify_consts: promotion candidate: place={:?}", place);
+                if let Place::Local(local) = *place {
+                    if self.mir.local_kind(local) == LocalKind::Temp {
+                        debug!("qualify_consts: promotion candidate: local={:?}", local);
+                        // The borrowed place doesn't have `HasMutInterior`
+                        // (from `in_rvalue`), so we can safely ignore
+                        // `HasMutInterior` from the local's qualifications.
+                        // This allows borrowing fields which don't have
+                        // `HasMutInterior`, from a type that does, e.g.:
+                        // `let _: &'static _ = &(Cell::new(1), 2).1;`
+                        let mut local_qualifs = self.qualifs_in_local(local);
+                        local_qualifs[HasMutInterior] = false;
+                        if !local_qualifs.0.iter().any(|&qualif| qualif) {
+                            debug!("qualify_consts: promotion candidate: {:?}", candidate);
+                            self.promotion_candidates.push(candidate);
+                        }
+                    }
                 }
             }
-            return;
         }
 
         let mut dest = dest;
@@ -242,21 +781,44 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
                 }
             }
         };
-        debug!("store to var {:?}", index);
-        match &mut self.local_qualif[index] {
-            // this is overly restrictive, because even full assignments do not clear the qualif
-            // While we could special case full assignments, this would be inconsistent with
-            // aggregates where we overwrite all fields via assignments, which would not get
-            // that feature.
-            Some(ref mut qualif) => *qualif = *qualif | self.qualif,
-            // insert new qualification
-            qualif @ None => *qualif = Some(self.qualif),
+
+        let kind = self.mir.local_kind(index);
+        debug!("store to {:?} {:?}", kind, index);
+
+        // Only handle promotable temps in non-const functions.
+        if self.mode == Mode::Fn {
+            if kind != LocalKind::Temp ||
+               !self.temp_promotion_state[index].is_promotable() {
+                return;
+            }
+        }
+
+        // this is overly restrictive, because even full assignments do not clear the qualif
+        // While we could special case full assignments, this would be inconsistent with
+        // aggregates where we overwrite all fields via assignments, which would not get
+        // that feature.
+        for (per_local, qualif) in &mut self.cx.per_local.as_mut().zip(qualifs).0 {
+            if *qualif {
+                per_local.insert(index);
+            }
+        }
+
+        // Ensure the `IsNotPromotable` qualification is preserved.
+        // NOTE(eddyb) this is actually unnecessary right now, as
+        // we never replace the local's qualif, but we might in
+        // the future, and so it serves to catch changes that unset
+        // important bits (in which case, asserting `contains` could
+        // be replaced with calling `insert` to re-set the bit).
+        if kind == LocalKind::Temp {
+            if !self.temp_promotion_state[index].is_promotable() {
+                assert!(self.cx.per_local[IsNotPromotable].contains(index));
+            }
         }
     }
 
-    /// Qualify a whole const, static initializer or const fn.
-    fn qualify_const(&mut self) -> (Qualif, Lrc<BitSet<Local>>) {
-        debug!("qualifying {} {:?}", self.mode, self.def_id);
+    /// Check a whole const, static initializer or const fn.
+    fn check_const(&mut self) -> (u8, Lrc<BitSet<Local>>) {
+        debug!("const-checking {} {:?}", self.mode, self.def_id);
 
         let mir = self.mir;
 
@@ -307,16 +869,6 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
             }
         }
 
-        self.qualif = self.local_qualif[RETURN_PLACE].unwrap_or(Qualif::NOT_CONST);
-
-        // Account for errors in consts by using the
-        // conservative type qualification instead.
-        if self.qualif.intersects(Qualif::CONST_ERROR) {
-            self.qualif = Qualif::empty();
-            let return_ty = mir.return_ty();
-            self.add_type(return_ty);
-        }
-
 
         // Collect all the temps we need to promote.
         let mut promoted_temps = BitSet::new_empty(self.temp_promotion_state.len());
@@ -336,61 +888,35 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> {
             }
         }
 
-        (self.qualif, Lrc::new(promoted_temps))
-    }
-
-    fn is_const_panic_fn(&self, def_id: DefId) -> bool {
-        Some(def_id) == self.tcx.lang_items().panic_fn() ||
-        Some(def_id) == self.tcx.lang_items().begin_panic_fn()
-    }
-}
-
-/// Accumulates an Rvalue or Call's effects in self.qualif.
-/// For functions (constant or not), it also records
-/// candidates for promotion in promotion_candidates.
-impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
-    fn visit_local(&mut self,
-                   &local: &Local,
-                   _: PlaceContext<'tcx>,
-                   _: Location) {
-        debug!("visit_local: local={:?}", local);
-        let kind = self.mir.local_kind(local);
-        match kind {
-            LocalKind::ReturnPointer => {
-                self.not_const();
-            }
-            LocalKind::Var if self.mode == Mode::Fn => {
-                self.add(Qualif::NOT_CONST);
-            }
-            LocalKind::Var |
-            LocalKind::Arg |
-            LocalKind::Temp => {
-                if let LocalKind::Arg = kind {
-                    self.add(Qualif::FN_ARGUMENT);
-                }
+        let promoted_temps = Lrc::new(promoted_temps);
 
-                if !self.temp_promotion_state[local].is_promotable() {
-                    debug!("visit_local: (not promotable) local={:?}", local);
-                    self.add(Qualif::NOT_PROMOTABLE);
-                }
+        let mut qualifs = self.qualifs_in_local(RETURN_PLACE);
 
-                if let Some(qualif) = self.local_qualif[local] {
-                    self.add(qualif);
-                } else {
-                    self.not_const();
-                }
-            }
+        // Account for errors in consts by using the
+        // conservative type qualification instead.
+        if qualifs[IsNotConst] {
+            qualifs = self.qualifs_in_any_value_of_ty(mir.return_ty());
         }
+
+        (qualifs.encode_to_bits(), promoted_temps)
     }
+}
 
+/// Checks MIR for const-correctness, using `ConstCx`
+/// for value qualifications, and accumulates writes of
+/// rvalue/call results to locals, in `local_qualif`.
+/// For functions (constant or not), it also records
+/// candidates for promotion in `promotion_candidates`.
+impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
     fn visit_place(&mut self,
                     place: &Place<'tcx>,
                     context: PlaceContext<'tcx>,
                     location: Location) {
         debug!("visit_place: place={:?} context={:?} location={:?}", place, context, location);
+        self.super_place(place, context, location);
         match *place {
-            Place::Local(ref local) => self.visit_local(local, context, location),
-            Place::Promoted(_) => bug!("promoting already promoted MIR"),
+            Place::Local(_) |
+            Place::Promoted(_) => {}
             Place::Static(ref global) => {
                 if self.tcx
                        .get_attrs(global.def_id)
@@ -401,7 +927,6 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                                   "thread-local statics cannot be \
                                    accessed at compile-time");
                     }
-                    self.add(Qualif::NOT_CONST);
                     return;
                 }
 
@@ -419,7 +944,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     }
                     return;
                 }
-                self.add(Qualif::NOT_CONST);
+                unleash_miri!(self);
 
                 if self.mode != Mode::Fn {
                     let mut err = struct_span_err!(self.tcx.sess, self.span, E0013,
@@ -438,73 +963,64 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                 }
             }
             Place::Projection(ref proj) => {
-                self.nest(|this| {
-                    this.super_place(place, context, location);
-                    match proj.elem {
-                        ProjectionElem::Deref => {
-                            if context.is_mutating_use() {
-                                // `not_const` errors out in const contexts
-                                this.not_const()
-                            } else {
-                                // just make sure this doesn't get promoted
-                                this.add(Qualif::NOT_CONST);
-                            }
-                            let base_ty = proj.base.ty(this.mir, this.tcx).to_ty(this.tcx);
-                            match this.mode {
-                                Mode::Fn => {},
-                                _ => {
-                                    if let ty::RawPtr(_) = base_ty.sty {
-                                        if !this.tcx.features().const_raw_ptr_deref {
-                                            emit_feature_err(
-                                                &this.tcx.sess.parse_sess, "const_raw_ptr_deref",
-                                                this.span, GateIssue::Language,
-                                                &format!(
-                                                    "dereferencing raw pointers in {}s is unstable",
-                                                    this.mode,
-                                                ),
-                                            );
-                                        }
+                match proj.elem {
+                    ProjectionElem::Deref => {
+                        if context.is_mutating_use() {
+                            // `not_const` errors out in const contexts
+                            self.not_const()
+                        }
+                        let base_ty = proj.base.ty(self.mir, self.tcx).to_ty(self.tcx);
+                        match self.mode {
+                            Mode::Fn => {},
+                            _ => {
+                                if let ty::RawPtr(_) = base_ty.sty {
+                                    if !self.tcx.features().const_raw_ptr_deref {
+                                        emit_feature_err(
+                                            &self.tcx.sess.parse_sess, "const_raw_ptr_deref",
+                                            self.span, GateIssue::Language,
+                                            &format!(
+                                                "dereferencing raw pointers in {}s is unstable",
+                                                self.mode,
+                                            ),
+                                        );
                                     }
                                 }
                             }
                         }
+                    }
 
-                        ProjectionElem::ConstantIndex {..} |
-                        ProjectionElem::Subslice {..} |
-                        ProjectionElem::Field(..) |
-                        ProjectionElem::Index(_) => {
-                            let base_ty = proj.base.ty(this.mir, this.tcx).to_ty(this.tcx);
-                            if let Some(def) = base_ty.ty_adt_def() {
-                                if def.is_union() {
-                                    match this.mode {
-                                        Mode::Fn => this.not_const(),
-                                        Mode::ConstFn => {
-                                            if !this.tcx.features().const_fn_union {
-                                                emit_feature_err(
-                                                    &this.tcx.sess.parse_sess, "const_fn_union",
-                                                    this.span, GateIssue::Language,
-                                                    "unions in const fn are unstable",
-                                                );
-                                            }
-                                        },
-
-                                        | Mode::Static
-                                        | Mode::StaticMut
-                                        | Mode::Const
-                                        => {},
-                                    }
+                    ProjectionElem::ConstantIndex {..} |
+                    ProjectionElem::Subslice {..} |
+                    ProjectionElem::Field(..) |
+                    ProjectionElem::Index(_) => {
+                        let base_ty = proj.base.ty(self.mir, self.tcx).to_ty(self.tcx);
+                        if let Some(def) = base_ty.ty_adt_def() {
+                            if def.is_union() {
+                                match self.mode {
+                                    Mode::ConstFn => {
+                                        if !self.tcx.features().const_fn_union {
+                                            emit_feature_err(
+                                                &self.tcx.sess.parse_sess, "const_fn_union",
+                                                self.span, GateIssue::Language,
+                                                "unions in const fn are unstable",
+                                            );
+                                        }
+                                    },
+
+                                    | Mode::Fn
+                                    | Mode::Static
+                                    | Mode::StaticMut
+                                    | Mode::Const
+                                    => {},
                                 }
                             }
-
-                            let ty = place.ty(this.mir, this.tcx).to_ty(this.tcx);
-                            this.qualif.restrict(ty, this.tcx, this.param_env);
                         }
+                    }
 
-                        ProjectionElem::Downcast(..) => {
-                            this.not_const()
-                        }
+                    ProjectionElem::Downcast(..) => {
+                        self.not_const()
                     }
-                });
+                }
             }
         }
     }
@@ -514,40 +1030,23 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
         self.super_operand(operand, location);
 
         match *operand {
-            Operand::Copy(_) |
-            Operand::Move(_) => {
+            Operand::Move(ref place) => {
                 // Mark the consumed locals to indicate later drops are noops.
-                if let Operand::Move(Place::Local(local)) = *operand {
-                    self.local_qualif[local] = self.local_qualif[local].map(|q|
-                        q - Qualif::NEEDS_DROP
-                    );
-                }
-            }
-            Operand::Constant(ref constant) => {
-                if let ty::LazyConst::Unevaluated(def_id, _) = constant.literal {
-                    // Don't peek inside trait associated constants.
-                    if self.tcx.trait_of_item(*def_id).is_some() {
-                        self.add_type(constant.ty);
-                    } else {
-                        let (bits, _) = self.tcx.at(constant.span).mir_const_qualif(*def_id);
-
-                        let qualif = Qualif::from_bits(bits).expect("invalid mir_const_qualif");
-                        self.add(qualif);
-
-                        // Just in case the type is more specific than
-                        // the definition, e.g., impl associated const
-                        // with type parameters, take it into account.
-                        self.qualif.restrict(constant.ty, self.tcx, self.param_env);
-                    }
+                if let Place::Local(local) = *place {
+                    self.cx.per_local[NeedsDrop].remove(local);
                 }
             }
+            Operand::Copy(_) |
+            Operand::Constant(_) => {}
         }
     }
 
     fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
         debug!("visit_rvalue: rvalue={:?} location={:?}", rvalue, location);
-        // Recurse through operands and places.
+
+        // Check nested operands and places.
         if let Rvalue::Ref(region, kind, ref place) = *rvalue {
+            // Special-case reborrows.
             let mut is_reborrow = false;
             if let Place::Projection(ref proj) = *place {
                 if let ProjectionElem::Deref = proj.elem {
@@ -560,14 +1059,18 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
 
             if is_reborrow {
                 let ctx = match kind {
-                    BorrowKind::Shared =>
-                        PlaceContext::NonMutatingUse(NonMutatingUseContext::SharedBorrow(region)),
-                    BorrowKind::Shallow =>
-                        PlaceContext::NonMutatingUse(NonMutatingUseContext::ShallowBorrow(region)),
-                    BorrowKind::Unique =>
-                        PlaceContext::NonMutatingUse(NonMutatingUseContext::UniqueBorrow(region)),
-                    BorrowKind::Mut { .. } =>
-                        PlaceContext::MutatingUse(MutatingUseContext::Borrow(region)),
+                    BorrowKind::Shared => PlaceContext::NonMutatingUse(
+                        NonMutatingUseContext::SharedBorrow(region),
+                    ),
+                    BorrowKind::Shallow => PlaceContext::NonMutatingUse(
+                        NonMutatingUseContext::ShallowBorrow(region),
+                    ),
+                    BorrowKind::Unique => PlaceContext::NonMutatingUse(
+                        NonMutatingUseContext::UniqueBorrow(region),
+                    ),
+                    BorrowKind::Mut { .. } => PlaceContext::MutatingUse(
+                        MutatingUseContext::Borrow(region),
+                    ),
                 };
                 self.super_place(place, ctx, location);
             } else {
@@ -589,109 +1092,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
             Rvalue::Cast(CastKind::ClosureFnPointer, ..) |
             Rvalue::Cast(CastKind::Unsize, ..) |
             Rvalue::Discriminant(..) |
-            Rvalue::Len(_) => {}
-
-            Rvalue::Ref(_, kind, ref place) => {
-                let ty = place.ty(self.mir, self.tcx).to_ty(self.tcx);
-
-                // Default to forbidding the borrow and/or its promotion,
-                // due to the potential for direct or interior mutability,
-                // and only proceed by setting `forbidden_mut` to `false`.
-                let mut forbidden_mut = true;
-
-                if let BorrowKind::Mut { .. } = kind {
-                    // In theory, any zero-sized value could be borrowed
-                    // mutably without consequences. However, only &mut []
-                    // is allowed right now, and only in functions.
-                    if self.mode == Mode::StaticMut {
-                        // Inside a `static mut`, &mut [...] is also allowed.
-                        match ty.sty {
-                            ty::Array(..) | ty::Slice(_) => forbidden_mut = false,
-                            _ => {}
-                        }
-                    } else if let ty::Array(_, len) = ty.sty {
-                        // FIXME(eddyb) the `self.mode == Mode::Fn` condition
-                        // seems unnecessary, given that this is merely a ZST.
-                        if len.unwrap_usize(self.tcx) == 0 && self.mode == Mode::Fn {
-                            forbidden_mut = false;
-                        }
-                    }
-
-                    if forbidden_mut {
-                        self.add(Qualif::NOT_CONST);
-                        if self.mode != Mode::Fn {
-                            let mut err = struct_span_err!(self.tcx.sess,  self.span, E0017,
-                                                           "references in {}s may only refer \
-                                                            to immutable values", self.mode);
-                            err.span_label(self.span, format!("{}s require immutable values",
-                                                                self.mode));
-                            if self.tcx.sess.teach(&err.get_code().unwrap()) {
-                                err.note("References in statics and constants may only refer to \
-                                          immutable values.\n\n\
-                                          Statics are shared everywhere, and if they refer to \
-                                          mutable data one might violate memory safety since \
-                                          holding multiple mutable references to shared data is \
-                                          not allowed.\n\n\
-                                          If you really want global mutable state, try using \
-                                          static mut or a global UnsafeCell.");
-                            }
-                            err.emit();
-                        }
-                    }
-                } else {
-                    // Constants cannot be borrowed if they contain interior mutability as
-                    // it means that our "silent insertion of statics" could change
-                    // initializer values (very bad).
-                    if self.qualif.contains(Qualif::MUTABLE_INTERIOR) {
-                        // A reference of a MUTABLE_INTERIOR place is instead
-                        // NOT_CONST (see `if forbidden_mut` below), to avoid
-                        // duplicate errors (from reborrowing, for example).
-                        self.qualif = self.qualif - Qualif::MUTABLE_INTERIOR;
-                        if self.mode != Mode::Fn {
-                            span_err!(self.tcx.sess, self.span, E0492,
-                                      "cannot borrow a constant which may contain \
-                                       interior mutability, create a static instead");
-                        }
-                    } else {
-                        // We allow immutable borrows of frozen data.
-                        forbidden_mut = false;
-                    }
-                }
-
-                debug!("visit_rvalue: forbidden_mut={:?}", forbidden_mut);
-                if forbidden_mut {
-                    self.add(Qualif::NOT_CONST);
-                } else {
-                    // We might have a candidate for promotion.
-                    let candidate = Candidate::Ref(location);
-                    // We can only promote interior borrows of promotable temps.
-                    let mut place = place;
-                    while let Place::Projection(ref proj) = *place {
-                        if proj.elem == ProjectionElem::Deref {
-                            break;
-                        }
-                        place = &proj.base;
-                    }
-                    debug!("visit_rvalue: place={:?}", place);
-                    if let Place::Local(local) = *place {
-                        if self.mir.local_kind(local) == LocalKind::Temp {
-                            debug!("visit_rvalue: local={:?}", local);
-                            if let Some(qualif) = self.local_qualif[local] {
-                                // `forbidden_mut` is false, so we can safely ignore
-                                // `MUTABLE_INTERIOR` from the local's qualifications.
-                                // This allows borrowing fields which don't have
-                                // `MUTABLE_INTERIOR`, from a type that does, e.g.:
-                                // `let _: &'static _ = &(Cell::new(1), 2).1;`
-                                debug!("visit_rvalue: qualif={:?}", qualif);
-                                if (qualif - Qualif::MUTABLE_INTERIOR).is_empty() {
-                                    debug!("visit_rvalue: candidate={:?}", candidate);
-                                    self.promotion_candidates.push(candidate);
-                                }
-                            }
-                        }
-                    }
-                }
-            }
+            Rvalue::Len(_) |
+            Rvalue::Ref(..) |
+            Rvalue::Aggregate(..) => {}
 
             Rvalue::Cast(CastKind::Misc, ref operand, cast_ty) => {
                 let operand_ty = operand.ty(self.mir, self.tcx);
@@ -699,11 +1102,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                 let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
                 match (cast_in, cast_out) {
                     (CastTy::Ptr(_), CastTy::Int(_)) |
-                    (CastTy::FnPtr, CastTy::Int(_)) => {
-                        if let Mode::Fn = self.mode {
-                            // in normal functions, mark such casts as not promotable
-                            self.add(Qualif::NOT_CONST);
-                        } else if !self.tcx.features().const_raw_ptr_to_usize_cast {
+                    (CastTy::FnPtr, CastTy::Int(_)) if self.mode != Mode::Fn => {
+                        unleash_miri!(self);
+                        if !self.tcx.features().const_raw_ptr_to_usize_cast {
                             // in const fn and constants require the feature gate
                             // FIXME: make it unsafe inside const fn and constants
                             emit_feature_err(
@@ -727,10 +1128,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                             op == BinOp::Ge || op == BinOp::Gt ||
                             op == BinOp::Offset);
 
-                    if let Mode::Fn = self.mode {
-                        // raw pointer operations are not allowed inside promoteds
-                        self.add(Qualif::NOT_CONST);
-                    } else if !self.tcx.features().const_compare_raw_pointers {
+                    unleash_miri!(self);
+                    if self.mode != Mode::Fn && !self.tcx.features().const_compare_raw_pointers {
                         // require the feature gate inside constants and const fn
                         // FIXME: make it unsafe to use these operations
                         emit_feature_err(
@@ -745,7 +1144,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
             }
 
             Rvalue::NullaryOp(NullOp::Box, _) => {
-                self.add(Qualif::NOT_CONST);
+                unleash_miri!(self);
                 if self.mode != Mode::Fn {
                     let mut err = struct_span_err!(self.tcx.sess, self.span, E0010,
                                                    "allocations are not allowed in {}s", self.mode);
@@ -761,20 +1160,6 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     err.emit();
                 }
             }
-
-            Rvalue::Aggregate(ref kind, _) => {
-                if let AggregateKind::Adt(def, ..) = **kind {
-                    if def.has_dtor(self.tcx) {
-                        self.add(Qualif::NEEDS_DROP);
-                    }
-
-                    if Some(def.did) == self.tcx.lang_items().unsafe_cell_type() {
-                        let ty = rvalue.ty(self.mir, self.tcx);
-                        self.add_type(ty);
-                        assert!(self.qualif.contains(Qualif::MUTABLE_INTERIOR));
-                    }
-                }
-            }
         }
     }
 
@@ -784,13 +1169,17 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                              location: Location) {
         debug!("visit_terminator_kind: bb={:?} kind={:?} location={:?}", bb, kind, location);
         if let TerminatorKind::Call { ref func, ref args, ref destination, .. } = *kind {
-            self.visit_operand(func, location);
+            if let Some((ref dest, _)) = *destination {
+                self.assign(dest, ValueSource::Call {
+                    callee: func,
+                    args,
+                    return_ty: dest.ty(self.mir, self.tcx).to_ty(self.tcx),
+                }, location);
+            }
 
             let fn_ty = func.ty(self.mir, self.tcx);
             let mut callee_def_id = None;
             let mut is_shuffle = false;
-            let mut is_const_fn = false;
-            let mut is_promotable_const_fn = false;
             match fn_ty.sty {
                 ty::FnDef(def_id, _) => {
                     callee_def_id = Some(def_id);
@@ -799,36 +1188,11 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                         Abi::PlatformIntrinsic => {
                             assert!(!self.tcx.is_const_fn(def_id));
                             match &self.tcx.item_name(def_id).as_str()[..] {
-                                | "size_of"
-                                | "min_align_of"
-                                | "needs_drop"
-                                | "type_id"
-                                | "bswap"
-                                | "bitreverse"
-                                | "ctpop"
-                                | "cttz"
-                                | "cttz_nonzero"
-                                | "ctlz"
-                                | "ctlz_nonzero"
-                                | "overflowing_add"
-                                | "overflowing_sub"
-                                | "overflowing_mul"
-                                | "unchecked_shl"
-                                | "unchecked_shr"
-                                | "rotate_left"
-                                | "rotate_right"
-                                | "add_with_overflow"
-                                | "sub_with_overflow"
-                                | "mul_with_overflow"
-                                // no need to check feature gates, intrinsics are only callable
-                                // from the libstd or with forever unstable feature gates
-                                => is_const_fn = true,
                                 // special intrinsic that can be called diretly without an intrinsic
                                 // feature gate needs a language feature gate
                                 "transmute" => {
                                     // never promote transmute calls
                                     if self.mode != Mode::Fn {
-                                        is_const_fn = true;
                                         // const eval transmute calls only with the feature gate
                                         if !self.tcx.features().const_transmute {
                                             emit_feature_err(
@@ -844,33 +1208,30 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                                     is_shuffle = true;
                                 }
 
+                                // no need to check feature gates, intrinsics are only callable
+                                // from the libstd or with forever unstable feature gates
                                 _ => {}
                             }
                         }
                         _ => {
-                            // In normal functions we only care about promotion.
-                            if self.mode == Mode::Fn {
-                                // Never promote const fn calls of
-                                // functions without `#[rustc_promotable]`.
-                                if self.tcx.is_promotable_const_fn(def_id) {
-                                    is_const_fn = true;
-                                    is_promotable_const_fn = true;
-                                } else if self.tcx.is_const_fn(def_id) {
-                                    is_const_fn = true;
-                                }
-                            } else {
-                                // stable const fns or unstable const fns with their feature gate
-                                // active
-                                if self.tcx.is_const_fn(def_id) {
-                                    is_const_fn = true;
+                            // In normal functions no calls are feature-gated.
+                            if self.mode != Mode::Fn {
+                                let unleash_miri = self
+                                    .tcx
+                                    .sess
+                                    .opts
+                                    .debugging_opts
+                                    .unleash_the_miri_inside_of_you;
+                                if self.tcx.is_const_fn(def_id) || unleash_miri {
+                                    // stable const fns or unstable const fns
+                                    // with their feature gate active
+                                    // FIXME(eddyb) move stability checks from `is_const_fn` here.
                                 } else if self.is_const_panic_fn(def_id) {
                                     // Check the const_panic feature gate.
                                     // FIXME: cannot allow this inside `allow_internal_unstable`
                                     // because that would make `panic!` insta stable in constants,
                                     // since the macro is marked with the attribute.
-                                    if self.tcx.features().const_panic {
-                                        is_const_fn = true;
-                                    } else {
+                                    if !self.tcx.features().const_panic {
                                         // Don't allow panics in constants without the feature gate.
                                         emit_feature_err(
                                             &self.tcx.sess.parse_sess,
@@ -885,10 +1246,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                                     // Check `#[unstable]` const fns or `#[rustc_const_unstable]`
                                     // functions without the feature gate active in this crate in
                                     // order to report a better error message than the one below.
-                                    if self.span.allows_unstable() {
-                                        // `allow_internal_unstable` can make such calls stable.
-                                        is_const_fn = true;
-                                    } else {
+                                    if !self.span.allows_unstable(&feature.as_str()) {
                                         let mut err = self.tcx.sess.struct_span_err(self.span,
                                             &format!("`{}` is not yet stable as a const fn",
                                                     self.tcx.item_path_str(def_id)));
@@ -901,38 +1259,20 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                                         err.emit();
                                     }
                                 } else {
-                                    // FIXME(#57563): remove this check when const fn stabilizes.
-                                    let (msg, note) = if let UnstableFeatures::Disallow =
-                                            self.tcx.sess.opts.unstable_features {
-                                        (format!("calls in {}s are limited to \
-                                                tuple structs and tuple variants",
-                                                self.mode),
-                                        Some("a limited form of compile-time function \
-                                            evaluation is available on a nightly \
-                                            compiler via `const fn`"))
-                                    } else {
-                                        (format!("calls in {}s are limited \
-                                                to constant functions, \
-                                                tuple structs and tuple variants",
-                                                self.mode),
-                                        None)
-                                    };
                                     let mut err = struct_span_err!(
                                         self.tcx.sess,
                                         self.span,
                                         E0015,
-                                        "{}",
-                                        msg,
+                                        "calls in {}s are limited to constant functions, \
+                                         tuple structs and tuple variants",
+                                        self.mode,
                                     );
-                                    if let Some(note) = note {
-                                        err.span_note(self.span, note);
-                                    }
                                     err.emit();
                                 }
                             }
                         }
                     }
-                },
+                }
                 ty::FnPtr(_) => {
                     if self.mode != Mode::Fn {
                         let mut err = self.tcx.sess.struct_span_err(
@@ -940,42 +1280,22 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                             &format!("function pointers are not allowed in const fn"));
                         err.emit();
                     }
-                },
+                }
                 _ => {
                     self.not_const();
-                    return
                 }
             }
 
-
-            let constant_arguments = callee_def_id.and_then(|id| {
-                args_required_const(self.tcx, id)
-            });
-            for (i, arg) in args.iter().enumerate() {
-                self.nest(|this| {
-                    this.visit_operand(arg, location);
-                    if this.mode != Mode::Fn {
-                        return
-                    }
-                    let candidate = Candidate::Argument { bb, index: i };
-                    if is_shuffle && i == 2 {
-                        if this.qualif.is_empty() {
-                            debug!("visit_terminator_kind: candidate={:?}", candidate);
-                            this.promotion_candidates.push(candidate);
-                        } else {
-                            span_err!(this.tcx.sess, this.span, E0526,
-                                      "shuffle indices are not constant");
-                        }
-                        return
+            if self.mode == Mode::Fn {
+                let constant_args = callee_def_id.and_then(|id| {
+                    args_required_const(self.tcx, id)
+                }).unwrap_or_default();
+                for (i, arg) in args.iter().enumerate() {
+                    if !(is_shuffle && i == 2 || constant_args.contains(&i)) {
+                        continue;
                     }
 
-                    let constant_arguments = match constant_arguments.as_ref() {
-                        Some(s) => s,
-                        None => return,
-                    };
-                    if !constant_arguments.contains(&i) {
-                        return
-                    }
+                    let candidate = Candidate::Argument { bb, index: i };
                     // Since the argument is required to be constant,
                     // we care about constness, not promotability.
                     // If we checked for promotability, we'd miss out on
@@ -986,54 +1306,37 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     // which happens even without the user requesting it.
                     // We can error out with a hard error if the argument is not
                     // constant here.
-                    if (this.qualif - Qualif::NOT_PROMOTABLE).is_empty() {
+                    if !IsNotConst::in_operand(self, arg) {
                         debug!("visit_terminator_kind: candidate={:?}", candidate);
-                        this.promotion_candidates.push(candidate);
+                        self.promotion_candidates.push(candidate);
                     } else {
-                        this.tcx.sess.span_err(this.span,
-                            &format!("argument {} is required to be a constant",
-                                     i + 1));
+                        if is_shuffle {
+                            span_err!(self.tcx.sess, self.span, E0526,
+                                      "shuffle indices are not constant");
+                        } else {
+                            self.tcx.sess.span_err(self.span,
+                                &format!("argument {} is required to be a constant",
+                                         i + 1));
+                        }
                     }
-                });
-            }
-
-            // non-const fn calls
-            if !is_const_fn {
-                self.qualif = Qualif::NOT_CONST;
-                if self.mode != Mode::Fn {
-                    self.tcx.sess.delay_span_bug(
-                        self.span,
-                        "should have reported an error about non-const fn calls in constants",
-                    )
                 }
             }
 
-            if let Some((ref dest, _)) = *destination {
-                // Avoid propagating irrelevant callee/argument qualifications.
-                if self.qualif.intersects(Qualif::CONST_ERROR) {
-                    self.qualif = Qualif::NOT_CONST;
-                } else {
-                    // Be conservative about the returned value of a const fn.
-                    let tcx = self.tcx;
-                    let ty = dest.ty(self.mir, tcx).to_ty(tcx);
-                    if is_const_fn && !is_promotable_const_fn && self.mode == Mode::Fn {
-                        self.qualif = Qualif::NOT_PROMOTABLE;
-                    } else {
-                        self.qualif = Qualif::empty();
-                    }
-                    self.add_type(ty);
-                }
-                self.assign(dest, location);
+            // Check callee and argument operands.
+            self.visit_operand(func, location);
+            for arg in args {
+                self.visit_operand(arg, location);
             }
         } else if let TerminatorKind::Drop { location: ref place, .. } = *kind {
             self.super_terminator_kind(bb, kind, location);
 
             // Deny *any* live drops anywhere other than functions.
             if self.mode != Mode::Fn {
+                unleash_miri!(self);
                 // HACK(eddyb): emulate a bit of dataflow analysis,
                 // conservatively, that drop elaboration will do.
                 let needs_drop = if let Place::Local(local) = *place {
-                    if self.local_qualif[local].map_or(true, |q| q.contains(Qualif::NEEDS_DROP)) {
+                    if NeedsDrop::in_local(self, local) {
                         Some(self.mir.local_decls[local].source_info.span)
                     } else {
                         None
@@ -1066,9 +1369,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     rvalue: &Rvalue<'tcx>,
                     location: Location) {
         debug!("visit_assign: dest={:?} rvalue={:?} location={:?}", dest, rvalue, location);
-        self.visit_rvalue(rvalue, location);
+        self.assign(dest, ValueSource::Rvalue(rvalue), location);
 
-        self.assign(dest, location);
+        self.visit_rvalue(rvalue, location);
     }
 
     fn visit_source_info(&mut self, source_info: &SourceInfo) {
@@ -1078,22 +1381,20 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
 
     fn visit_statement(&mut self, bb: BasicBlock, statement: &Statement<'tcx>, location: Location) {
         debug!("visit_statement: bb={:?} statement={:?} location={:?}", bb, statement, location);
-        self.nest(|this| {
-            this.visit_source_info(&statement.source_info);
-            match statement.kind {
-                StatementKind::Assign(ref place, ref rvalue) => {
-                    this.visit_assign(bb, place, rvalue, location);
-                }
-                StatementKind::FakeRead(..) |
-                StatementKind::SetDiscriminant { .. } |
-                StatementKind::StorageLive(_) |
-                StatementKind::StorageDead(_) |
-                StatementKind::InlineAsm {..} |
-                StatementKind::Retag { .. } |
-                StatementKind::AscribeUserType(..) |
-                StatementKind::Nop => {}
+        match statement.kind {
+            StatementKind::Assign(..) => {
+                self.super_statement(bb, statement, location);
             }
-        });
+            // FIXME(eddyb) should these really do nothing?
+            StatementKind::FakeRead(..) |
+            StatementKind::SetDiscriminant { .. } |
+            StatementKind::StorageLive(_) |
+            StatementKind::StorageDead(_) |
+            StatementKind::InlineAsm {..} |
+            StatementKind::Retag { .. } |
+            StatementKind::AscribeUserType(..) |
+            StatementKind::Nop => {}
+        }
     }
 
     fn visit_terminator(&mut self,
@@ -1101,11 +1402,11 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                         terminator: &Terminator<'tcx>,
                         location: Location) {
         debug!("visit_terminator: bb={:?} terminator={:?} location={:?}", bb, terminator, location);
-        self.nest(|this| this.super_terminator(bb, terminator, location));
+        self.super_terminator(bb, terminator, location);
     }
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         mir_const_qualif,
         ..*providers
@@ -1123,12 +1424,10 @@ fn mir_const_qualif<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
     if mir.return_ty().references_error() {
         tcx.sess.delay_span_bug(mir.span, "mir_const_qualif: Mir had errors");
-        return (Qualif::NOT_CONST.bits(), Lrc::new(BitSet::new_empty(0)));
+        return (1 << IsNotConst::IDX, Lrc::new(BitSet::new_empty(0)));
     }
 
-    let mut qualifier = Qualifier::new(tcx, def_id, mir, Mode::Const);
-    let (qualif, promoted_temps) = qualifier.qualify_const();
-    (qualif.bits(), promoted_temps)
+    Checker::new(tcx, def_id, mir, Mode::Const).check_const()
 }
 
 pub struct QualifyAndPromoteConstants;
@@ -1136,7 +1435,7 @@ pub struct QualifyAndPromoteConstants;
 impl MirPass for QualifyAndPromoteConstants {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          src: MirSource,
+                          src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         // There's not really any point in promoting errorful MIR.
         if mir.return_ty().references_error() {
@@ -1148,10 +1447,11 @@ impl MirPass for QualifyAndPromoteConstants {
             return;
         }
 
-        let def_id = src.def_id;
-        let id = tcx.hir().as_local_node_id(def_id).unwrap();
+        let def_id = src.def_id();
+        let id = tcx.hir().as_local_hir_id(def_id).unwrap();
         let mut const_promoted_temps = None;
-        let mode = match tcx.hir().body_owner_kind(id) {
+        let mode = match tcx.hir().body_owner_kind_by_hir_id(id) {
+            hir::BodyOwnerKind::Closure => Mode::Fn,
             hir::BodyOwnerKind::Fn => {
                 if tcx.is_const_fn(def_id) {
                     Mode::ConstFn
@@ -1169,32 +1469,44 @@ impl MirPass for QualifyAndPromoteConstants {
 
         debug!("run_pass: mode={:?}", mode);
         if mode == Mode::Fn || mode == Mode::ConstFn {
-            // This is ugly because Qualifier holds onto mir,
+            // This is ugly because Checker holds onto mir,
             // which can't be mutated until its scope ends.
             let (temps, candidates) = {
-                let mut qualifier = Qualifier::new(tcx, def_id, mir, mode);
+                let mut checker = Checker::new(tcx, def_id, mir, mode);
                 if mode == Mode::ConstFn {
-                    if tcx.is_min_const_fn(def_id) {
+                    if tcx.sess.opts.debugging_opts.unleash_the_miri_inside_of_you {
+                        checker.check_const();
+                    } else if tcx.is_min_const_fn(def_id) {
                         // enforce `min_const_fn` for stable const fns
                         use super::qualify_min_const_fn::is_min_const_fn;
                         if let Err((span, err)) = is_min_const_fn(tcx, def_id, mir) {
-                            tcx.sess.span_err(span, &err);
+                            let mut diag = struct_span_err!(
+                                tcx.sess,
+                                span,
+                                E0723,
+                                "{} (see issue #57563)",
+                                err,
+                            );
+                            diag.help(
+                                "add #![feature(const_fn)] to the crate attributes to enable",
+                            );
+                            diag.emit();
                         } else {
                             // this should not produce any errors, but better safe than sorry
                             // FIXME(#53819)
-                            qualifier.qualify_const();
+                            checker.check_const();
                         }
                     } else {
                         // Enforce a constant-like CFG for `const fn`.
-                        qualifier.qualify_const();
+                        checker.check_const();
                     }
                 } else {
-                    while let Some((bb, data)) = qualifier.rpo.next() {
-                        qualifier.visit_basic_block_data(bb, data);
+                    while let Some((bb, data)) = checker.rpo.next() {
+                        checker.visit_basic_block_data(bb, data);
                     }
                 }
 
-                (qualifier.temp_promotion_state, qualifier.promotion_candidates)
+                (checker.temp_promotion_state, checker.promotion_candidates)
             };
 
             // Do the actual promotion, now that we know what's viable.
@@ -1235,7 +1547,7 @@ impl MirPass for QualifyAndPromoteConstants {
                 // Already computed by `mir_const_qualif`.
                 const_promoted_temps.unwrap()
             } else {
-                Qualifier::new(tcx, def_id, mir, mode).qualify_const().1
+                Checker::new(tcx, def_id, mir, mode).check_const().1
             };
 
             // In `const` and `static` everything without `StorageDead`
@@ -1291,7 +1603,7 @@ impl MirPass for QualifyAndPromoteConstants {
     }
 }
 
-fn args_required_const(tcx: TyCtxt, def_id: DefId) -> Option<FxHashSet<usize>> {
+fn args_required_const(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Option<FxHashSet<usize>> {
     let attrs = tcx.get_attrs(def_id);
     let attr = attrs.iter().find(|a| a.check_name("rustc_args_required_const"))?;
     let mut ret = FxHashSet::default();
diff --git a/src/librustc_mir/transform/qualify_min_const_fn.rs b/src/librustc_mir/transform/qualify_min_const_fn.rs
index 059b88a4d702a..34f850fc4aad2 100644
--- a/src/librustc_mir/transform/qualify_min_const_fn.rs
+++ b/src/librustc_mir/transform/qualify_min_const_fn.rs
@@ -21,6 +21,7 @@ pub fn is_min_const_fn(
                 | Predicate::RegionOutlives(_)
                 | Predicate::TypeOutlives(_)
                 | Predicate::WellFormed(_)
+                | Predicate::Projection(_)
                 | Predicate::ConstEvaluatable(..) => continue,
                 | Predicate::ObjectSafe(_) => {
                     bug!("object safe predicate on function: {:#?}", predicate)
@@ -29,13 +30,6 @@ pub fn is_min_const_fn(
                     bug!("closure kind predicate on function: {:#?}", predicate)
                 }
                 Predicate::Subtype(_) => bug!("subtype predicate on function: {:#?}", predicate),
-                Predicate::Projection(_) => {
-                    let span = tcx.def_span(current);
-                    // we'll hit a `Predicate::Trait` later which will report an error
-                    tcx.sess
-                        .delay_span_bug(span, "projection without trait bound");
-                    continue;
-                }
                 Predicate::Trait(pred) => {
                     if Some(pred.def_id()) == tcx.lang_items().sized_trait() {
                         continue;
@@ -364,7 +358,7 @@ fn check_terminator(
     }
 }
 
-/// Returns true if the `def_id` refers to an intrisic which we've whitelisted
+/// Returns `true` if the `def_id` refers to an intrisic which we've whitelisted
 /// for being called from stable `const fn`s (`min_const_fn`).
 ///
 /// Adding more intrinsics requires sign-off from @rust-lang/lang.
@@ -380,6 +374,8 @@ fn is_intrinsic_whitelisted(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> bool
         | "overflowing_add" // ~> .wrapping_add
         | "overflowing_sub" // ~> .wrapping_sub
         | "overflowing_mul" // ~> .wrapping_mul
+        | "saturating_add" // ~> .saturating_add
+        | "saturating_sub" // ~> .saturating_sub
         | "unchecked_shl" // ~> .wrapping_shl
         | "unchecked_shr" // ~> .wrapping_shr
         | "rotate_left" // ~> .rotate_left
diff --git a/src/librustc_mir/transform/remove_noop_landing_pads.rs b/src/librustc_mir/transform/remove_noop_landing_pads.rs
index c8ef2decf2606..0ad33bff9d6ca 100644
--- a/src/librustc_mir/transform/remove_noop_landing_pads.rs
+++ b/src/librustc_mir/transform/remove_noop_landing_pads.rs
@@ -1,10 +1,10 @@
 use rustc::ty::TyCtxt;
 use rustc::mir::*;
 use rustc_data_structures::bit_set::BitSet;
-use transform::{MirPass, MirSource};
-use util::patch::MirPatch;
+use crate::transform::{MirPass, MirSource};
+use crate::util::patch::MirPatch;
 
-/// A pass that removes no-op landing pads and replaces jumps to them with
+/// A pass that removes noop landing pads and replaces jumps to them with
 /// `None`. This is important because otherwise LLVM generates terrible
 /// code for these.
 pub struct RemoveNoopLandingPads;
@@ -24,7 +24,7 @@ pub fn remove_noop_landing_pads<'a, 'tcx>(
 impl MirPass for RemoveNoopLandingPads {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         remove_noop_landing_pads(tcx, mir);
     }
@@ -34,7 +34,7 @@ impl RemoveNoopLandingPads {
     fn is_nop_landing_pad(
         &self,
         bb: BasicBlock,
-        mir: &Mir,
+        mir: &Mir<'_>,
         nop_landing_pads: &BitSet<BasicBlock>,
     ) -> bool {
         for stmt in &mir[bb].statements {
@@ -86,7 +86,7 @@ impl RemoveNoopLandingPads {
         }
     }
 
-    fn remove_nop_landing_pads(&self, mir: &mut Mir) {
+    fn remove_nop_landing_pads(&self, mir: &mut Mir<'_>) {
         // make sure there's a single resume block
         let resume_block = {
             let patch = MirPatch::new(mir);
diff --git a/src/librustc_mir/transform/rustc_peek.rs b/src/librustc_mir/transform/rustc_peek.rs
index 36a6279e50320..40e02e712c156 100644
--- a/src/librustc_mir/transform/rustc_peek.rs
+++ b/src/librustc_mir/transform/rustc_peek.rs
@@ -5,25 +5,27 @@ use syntax_pos::Span;
 use rustc::ty::{self, TyCtxt};
 use rustc::mir::{self, Mir, Location};
 use rustc_data_structures::bit_set::BitSet;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
-use dataflow::{do_dataflow, DebugFormatted};
-use dataflow::MoveDataParamEnv;
-use dataflow::BitDenotation;
-use dataflow::DataflowResults;
-use dataflow::{DefinitelyInitializedPlaces, MaybeInitializedPlaces, MaybeUninitializedPlaces};
-use dataflow::move_paths::{MovePathIndex, LookupResult};
-use dataflow::move_paths::{HasMoveData, MoveData};
-use dataflow;
+use crate::dataflow::{do_dataflow, DebugFormatted};
+use crate::dataflow::MoveDataParamEnv;
+use crate::dataflow::BitDenotation;
+use crate::dataflow::DataflowResults;
+use crate::dataflow::{
+    DefinitelyInitializedPlaces, MaybeInitializedPlaces, MaybeUninitializedPlaces
+};
+use crate::dataflow::move_paths::{MovePathIndex, LookupResult};
+use crate::dataflow::move_paths::{HasMoveData, MoveData};
+use crate::dataflow;
 
-use dataflow::has_rustc_mir_with;
+use crate::dataflow::has_rustc_mir_with;
 
 pub struct SanityCheck;
 
 impl MirPass for SanityCheck {
     fn run_pass<'a, 'tcx>(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          src: MirSource, mir: &mut Mir<'tcx>) {
-        let def_id = src.def_id;
+                          src: MirSource<'tcx>, mir: &mut Mir<'tcx>) {
+        let def_id = src.def_id();
         let id = tcx.hir().as_local_node_id(def_id).unwrap();
         if !tcx.has_attr(def_id, "rustc_mir") {
             debug!("skipping rustc_peek::SanityCheck on {}", tcx.item_path_str(def_id));
diff --git a/src/librustc_mir/transform/simplify.rs b/src/librustc_mir/transform/simplify.rs
index ed2da98dd5311..14e7895af0419 100644
--- a/src/librustc_mir/transform/simplify.rs
+++ b/src/librustc_mir/transform/simplify.rs
@@ -34,7 +34,7 @@ use rustc::mir::*;
 use rustc::mir::visit::{MutVisitor, Visitor, PlaceContext};
 use rustc::session::config::DebugInfo;
 use std::borrow::Cow;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 pub struct SimplifyCfg { label: String }
 
@@ -44,7 +44,7 @@ impl SimplifyCfg {
     }
 }
 
-pub fn simplify_cfg(mir: &mut Mir) {
+pub fn simplify_cfg(mir: &mut Mir<'_>) {
     CfgSimplifier::new(mir).simplify();
     remove_dead_blocks(mir);
 
@@ -59,7 +59,7 @@ impl MirPass for SimplifyCfg {
 
     fn run_pass<'a, 'tcx>(&self,
                           _tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         debug!("SimplifyCfg({:?}) - simplifying {:?}", self.label, mir);
         simplify_cfg(mir);
@@ -263,7 +263,7 @@ impl<'a, 'tcx: 'a> CfgSimplifier<'a, 'tcx> {
     }
 }
 
-pub fn remove_dead_blocks(mir: &mut Mir) {
+pub fn remove_dead_blocks(mir: &mut Mir<'_>) {
     let mut seen = BitSet::new_empty(mir.basic_blocks().len());
     for (bb, _) in traversal::preorder(mir) {
         seen.insert(bb.index());
@@ -298,7 +298,7 @@ pub struct SimplifyLocals;
 impl MirPass for SimplifyLocals {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _: MirSource,
+                          _: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let mut marker = DeclMarker { locals: BitSet::new_empty(mir.local_decls.len()) };
         marker.visit_mir(mir);
diff --git a/src/librustc_mir/transform/simplify_branches.rs b/src/librustc_mir/transform/simplify_branches.rs
index abaea70946383..3c4d1227a691c 100644
--- a/src/librustc_mir/transform/simplify_branches.rs
+++ b/src/librustc_mir/transform/simplify_branches.rs
@@ -2,7 +2,7 @@
 
 use rustc::ty::{TyCtxt, ParamEnv};
 use rustc::mir::*;
-use transform::{MirPass, MirSource};
+use crate::transform::{MirPass, MirSource};
 
 use std::borrow::Cow;
 
@@ -21,7 +21,7 @@ impl MirPass for SimplifyBranches {
 
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         for block in mir.basic_blocks_mut() {
             let terminator = block.terminator_mut();
diff --git a/src/librustc_mir/transform/uniform_array_move_out.rs b/src/librustc_mir/transform/uniform_array_move_out.rs
index 5ab9669baaca0..fd8d68a482262 100644
--- a/src/librustc_mir/transform/uniform_array_move_out.rs
+++ b/src/librustc_mir/transform/uniform_array_move_out.rs
@@ -30,16 +30,16 @@ use rustc::ty;
 use rustc::ty::TyCtxt;
 use rustc::mir::*;
 use rustc::mir::visit::{Visitor, PlaceContext, NonUseContext};
-use transform::{MirPass, MirSource};
-use util::patch::MirPatch;
 use rustc_data_structures::indexed_vec::{IndexVec};
+use crate::transform::{MirPass, MirSource};
+use crate::util::patch::MirPatch;
 
 pub struct UniformArrayMoveOut;
 
 impl MirPass for UniformArrayMoveOut {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let mut patch = MirPatch::new(mir);
         {
@@ -161,7 +161,7 @@ pub struct RestoreSubsliceArrayMoveOut;
 impl MirPass for RestoreSubsliceArrayMoveOut {
     fn run_pass<'a, 'tcx>(&self,
                           tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                          _src: MirSource,
+                          _src: MirSource<'tcx>,
                           mir: &mut Mir<'tcx>) {
         let mut patch = MirPatch::new(mir);
         {
diff --git a/src/librustc_mir/util/alignment.rs b/src/librustc_mir/util/alignment.rs
index 659b5beb30588..7be34d001df07 100644
--- a/src/librustc_mir/util/alignment.rs
+++ b/src/librustc_mir/util/alignment.rs
@@ -1,7 +1,7 @@
 use rustc::ty::{self, TyCtxt};
 use rustc::mir::*;
 
-/// Return `true` if this place is allowed to be less aligned
+/// Returns `true` if this place is allowed to be less aligned
 /// than its containing struct (because it is within a packed
 /// struct).
 pub fn is_disaligned<'a, 'tcx, L>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
diff --git a/src/librustc_mir/util/borrowck_errors.rs b/src/librustc_mir/util/borrowck_errors.rs
index 7ad73aaa3f9a9..fd694ddbbd19f 100644
--- a/src/librustc_mir/util/borrowck_errors.rs
+++ b/src/librustc_mir/util/borrowck_errors.rs
@@ -12,7 +12,7 @@ pub enum Origin {
 }
 
 impl fmt::Display for Origin {
-    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, w: &mut fmt::Formatter<'_>) -> fmt::Result {
         // If the user passed `-Z borrowck=compare`, then include
         // origin info as part of the error report,
         // otherwise
@@ -437,7 +437,7 @@ pub trait BorrowckErrors<'cx>: Sized + Copy {
     fn cannot_move_out_of_interior_noncopy(
         self,
         move_from_span: Span,
-        ty: ty::Ty,
+        ty: ty::Ty<'_>,
         is_index: Option<bool>,
         o: Origin,
     ) -> DiagnosticBuilder<'cx> {
@@ -464,7 +464,7 @@ pub trait BorrowckErrors<'cx>: Sized + Copy {
     fn cannot_move_out_of_interior_of_drop(
         self,
         move_from_span: Span,
-        container_ty: ty::Ty,
+        container_ty: ty::Ty<'_>,
         o: Origin,
     ) -> DiagnosticBuilder<'cx> {
         let mut err = struct_span_err!(
diff --git a/src/librustc_mir/util/def_use.rs b/src/librustc_mir/util/def_use.rs
index 057a7c8be88c9..2e41c6e493bc3 100644
--- a/src/librustc_mir/util/def_use.rs
+++ b/src/librustc_mir/util/def_use.rs
@@ -61,7 +61,7 @@ impl<'tcx> DefUseAnalysis<'tcx> {
         }
     }
 
-    /// FIXME(pcwalton): This should update the def-use chains.
+    // FIXME(pcwalton): this should update the def-use chains.
     pub fn replace_all_defs_and_uses_with(&self,
                                           local: Local,
                                           mir: &mut Mir<'tcx>,
@@ -107,7 +107,7 @@ impl<'tcx> Info<'tcx> {
 
     pub fn defs_not_including_drop(
         &self,
-    ) -> iter::Filter<slice::Iter<Use<'tcx>>, fn(&&Use<'tcx>) -> bool> {
+    ) -> iter::Filter<slice::Iter<'_, Use<'tcx>>, fn(&&Use<'tcx>) -> bool> {
         self.defs_and_uses.iter().filter(|place_use| {
             place_use.context.is_mutating_use() && !place_use.context.is_drop()
         })
diff --git a/src/librustc_mir/util/elaborate_drops.rs b/src/librustc_mir/util/elaborate_drops.rs
index 8b55a4424ae29..e86ece138301f 100644
--- a/src/librustc_mir/util/elaborate_drops.rs
+++ b/src/librustc_mir/util/elaborate_drops.rs
@@ -8,7 +8,7 @@ use rustc::ty::layout::VariantIdx;
 use rustc::ty::subst::Substs;
 use rustc::ty::util::IntTypeExt;
 use rustc_data_structures::indexed_vec::Idx;
-use util::patch::MirPatch;
+use crate::util::patch::MirPatch;
 
 use std::u32;
 
@@ -144,9 +144,9 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
     /// joined together under the `rest` subpath. They are all controlled
     /// by the primary drop flag, but only the last rest-field dropped
     /// should clear it (and it must also not clear anything else).
-    ///
-    /// FIXME: I think we should just control the flags externally
-    /// and then we do not need this machinery.
+    //
+    // FIXME: I think we should just control the flags externally,
+    // and then we do not need this machinery.
     pub fn elaborate_drop<'a>(&mut self, bb: BasicBlock) {
         debug!("elaborate_drop({:?})", self);
         let style = self.elaborator.drop_style(self.path, DropFlagMode::Deep);
@@ -183,7 +183,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
         }
     }
 
-    /// Return the place and move path for each field of `variant`,
+    /// Returns the place and move path for each field of `variant`,
     /// (the move path is `None` if the field is a rest field).
     fn move_paths_for_fields(&self,
                              base_place: &Place<'tcx>,
@@ -234,7 +234,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
         }
     }
 
-    /// Create one-half of the drop ladder for a list of fields, and return
+    /// Creates one-half of the drop ladder for a list of fields, and return
     /// the list of steps in it in reverse order, with the first step
     /// dropping 0 fields and so on.
     ///
@@ -268,7 +268,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
         )
     }
 
-    /// Create a full drop ladder, consisting of 2 connected half-drop-ladders
+    /// Creates a full drop ladder, consisting of 2 connected half-drop-ladders
     ///
     /// For example, with 3 fields, the drop ladder is
     ///
@@ -818,7 +818,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
         }
     }
 
-    /// Return a basic block that drop a place using the context
+    /// Returns a basic block that drop a place using the context
     /// and path in `c`. If `mode` is something, also clear `c`
     /// according to it.
     ///
@@ -963,7 +963,7 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
             span: self.source_info.span,
             ty: self.tcx().types.usize,
             user_ty: None,
-            literal: self.tcx().intern_lazy_const(ty::LazyConst::Evaluated(
+            literal: self.tcx().mk_lazy_const(ty::LazyConst::Evaluated(
                 ty::Const::from_usize(self.tcx(), val.into())
             )),
         })
diff --git a/src/librustc_mir/util/graphviz.rs b/src/librustc_mir/util/graphviz.rs
index b68898f713021..e93b96c12161c 100644
--- a/src/librustc_mir/util/graphviz.rs
+++ b/src/librustc_mir/util/graphviz.rs
@@ -1,4 +1,3 @@
-use dot;
 use rustc::hir::def_id::DefId;
 use rustc::mir::*;
 use rustc::ty::TyCtxt;
@@ -24,7 +23,7 @@ pub fn write_mir_graphviz<'tcx, W>(tcx: TyCtxt<'_, '_, 'tcx>,
 /// Write a graphviz DOT graph of the MIR.
 pub fn write_mir_fn_graphviz<'tcx, W>(tcx: TyCtxt<'_, '_, 'tcx>,
                                       def_id: DefId,
-                                      mir: &Mir,
+                                      mir: &Mir<'_>,
                                       w: &mut W) -> io::Result<()>
     where W: Write
 {
@@ -58,7 +57,7 @@ pub fn write_mir_fn_graphviz<'tcx, W>(tcx: TyCtxt<'_, '_, 'tcx>,
 /// `init` and `fini` are callbacks for emitting additional rows of
 /// data (using HTML enclosed with `<tr>` in the emitted text).
 pub fn write_node_label<W: Write, INIT, FINI>(block: BasicBlock,
-                                              mir: &Mir,
+                                              mir: &Mir<'_>,
                                               w: &mut W,
                                               num_cols: u32,
                                               init: INIT,
@@ -100,7 +99,7 @@ pub fn write_node_label<W: Write, INIT, FINI>(block: BasicBlock,
 }
 
 /// Write a graphviz DOT node for the given basic block.
-fn write_node<W: Write>(block: BasicBlock, mir: &Mir, w: &mut W) -> io::Result<()> {
+fn write_node<W: Write>(block: BasicBlock, mir: &Mir<'_>, w: &mut W) -> io::Result<()> {
     // Start a new node with the label to follow, in one of DOT's pseudo-HTML tables.
     write!(w, r#"    {} [shape="none", label=<"#, node(block))?;
     write_node_label(block, mir, w, 1, |_| Ok(()), |_| Ok(()))?;
@@ -109,7 +108,7 @@ fn write_node<W: Write>(block: BasicBlock, mir: &Mir, w: &mut W) -> io::Result<(
 }
 
 /// Write graphviz DOT edges with labels between the given basic block and all of its successors.
-fn write_edges<W: Write>(source: BasicBlock, mir: &Mir, w: &mut W) -> io::Result<()> {
+fn write_edges<W: Write>(source: BasicBlock, mir: &Mir<'_>, w: &mut W) -> io::Result<()> {
     let terminator = mir[source].terminator();
     let labels = terminator.kind.fmt_successor_labels();
 
@@ -125,7 +124,7 @@ fn write_edges<W: Write>(source: BasicBlock, mir: &Mir, w: &mut W) -> io::Result
 /// all the variables and temporaries.
 fn write_graph_label<'a, 'gcx, 'tcx, W: Write>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
                                                def_id: DefId,
-                                               mir: &Mir,
+                                               mir: &Mir<'_>,
                                                w: &mut W)
                                                -> io::Result<()> {
     write!(w, "    label=<fn {}(", dot::escape_html(&tcx.item_path_str(def_id)))?;
diff --git a/src/librustc_mir/util/liveness.rs b/src/librustc_mir/util/liveness.rs
index b68c6f8748fbe..dcbd9aa9af225 100644
--- a/src/librustc_mir/util/liveness.rs
+++ b/src/librustc_mir/util/liveness.rs
@@ -1,21 +1,22 @@
-//! Liveness analysis which computes liveness of MIR local variables at the boundary of basic blocks
+//! Liveness analysis which computes liveness of MIR local variables at the boundary of basic
+//! blocks.
 //!
 //! This analysis considers references as being used only at the point of the
 //! borrow. This means that this does not track uses because of references that
 //! already exist:
 //!
-//! ```Rust
-//!     fn foo() {
-//!         x = 0;
-//!         // `x` is live here
-//!         GLOBAL = &x: *const u32;
-//!         // but not here, even while it can be accessed through `GLOBAL`.
-//!         foo();
-//!         x = 1;
-//!         // `x` is live again here, because it is assigned to `OTHER_GLOBAL`
-//!         OTHER_GLOBAL = &x: *const u32;
-//!         // ...
-//!     }
+//! ```rust
+//! fn foo() {
+//!     x = 0;
+//!     // `x` is live here ...
+//!     GLOBAL = &x: *const u32;
+//!     // ... but not here, even while it can be accessed through `GLOBAL`.
+//!     foo();
+//!     x = 1;
+//!     // `x` is live again here, because it is assigned to `OTHER_GLOBAL`.
+//!     OTHER_GLOBAL = &x: *const u32;
+//!     // ...
+//! }
 //! ```
 //!
 //! This means that users of this analysis still have to check whether
@@ -35,8 +36,8 @@ use rustc_data_structures::work_queue::WorkQueue;
 use std::fs;
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
-use transform::MirSource;
-use util::pretty::{dump_enabled, write_basic_block, write_mir_intro};
+use crate::transform::MirSource;
+use crate::util::pretty::{dump_enabled, write_basic_block, write_mir_intro};
 
 pub type LiveVarSet<V> = BitSet<V>;
 
@@ -91,7 +92,7 @@ impl<'a, 'tcx> LiveVariableMap for IdentityMap<'a, 'tcx> {
     }
 }
 
-/// Compute which local variables are live within the given function
+/// Computes which local variables are live within the given function
 /// `mir`. The liveness mode `mode` determines what sorts of uses are
 /// considered to make a variable live (e.g., do drops count?).
 pub fn liveness_of_locals<'tcx, V: Idx>(
@@ -307,7 +308,7 @@ fn block<'tcx, V: Idx>(
 pub fn dump_mir<'a, 'tcx, V: Idx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     pass_name: &str,
-    source: MirSource,
+    source: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     map: &impl LiveVariableMap<LiveVar = V>,
     result: &LivenessResult<V>,
@@ -317,7 +318,7 @@ pub fn dump_mir<'a, 'tcx, V: Idx>(
     }
     let node_path = item_path::with_forced_impl_filename_line(|| {
         // see notes on #41697 below
-        tcx.item_path_str(source.def_id)
+        tcx.item_path_str(source.def_id())
     });
     dump_matched_mir_node(tcx, pass_name, &node_path, source, mir, map, result);
 }
@@ -326,14 +327,14 @@ fn dump_matched_mir_node<'a, 'tcx, V: Idx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     pass_name: &str,
     node_path: &str,
-    source: MirSource,
+    source: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     map: &dyn LiveVariableMap<LiveVar = V>,
     result: &LivenessResult<V>,
 ) {
     let mut file_path = PathBuf::new();
     file_path.push(Path::new(&tcx.sess.opts.debugging_opts.dump_mir_dir));
-    let item_id = tcx.hir().as_local_node_id(source.def_id).unwrap();
+    let item_id = tcx.hir().as_local_node_id(source.def_id()).unwrap();
     let file_name = format!("rustc.node{}{}-liveness.mir", item_id, pass_name);
     file_path.push(&file_name);
     let _ = fs::File::create(&file_path).and_then(|mut file| {
@@ -348,7 +349,7 @@ fn dump_matched_mir_node<'a, 'tcx, V: Idx>(
 
 pub fn write_mir_fn<'a, 'tcx, V: Idx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
-    src: MirSource,
+    src: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     map: &dyn LiveVariableMap<LiveVar = V>,
     w: &mut dyn Write,
diff --git a/src/librustc_mir/util/patch.rs b/src/librustc_mir/util/patch.rs
index 5a1f94677a1d4..366cd71f6d4e9 100644
--- a/src/librustc_mir/util/patch.rs
+++ b/src/librustc_mir/util/patch.rs
@@ -170,14 +170,14 @@ impl<'tcx> MirPatch<'tcx> {
         }
     }
 
-    pub fn source_info_for_index(data: &BasicBlockData, loc: Location) -> SourceInfo {
+    pub fn source_info_for_index(data: &BasicBlockData<'_>, loc: Location) -> SourceInfo {
         match data.statements.get(loc.statement_index) {
             Some(stmt) => stmt.source_info,
             None => data.terminator().source_info
         }
     }
 
-    pub fn source_info_for_location(&self, mir: &Mir, loc: Location) -> SourceInfo {
+    pub fn source_info_for_location(&self, mir: &Mir<'_>, loc: Location) -> SourceInfo {
         let data = match loc.block.index().checked_sub(mir.basic_blocks().len()) {
             Some(new) => &self.new_blocks[new],
             None => &mir[loc.block]
diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
index fca208b340d2a..8177de50776d6 100644
--- a/src/librustc_mir/util/pretty.rs
+++ b/src/librustc_mir/util/pretty.rs
@@ -1,4 +1,3 @@
-use rustc::hir;
 use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::mir::*;
 use rustc::mir::visit::Visitor;
@@ -12,7 +11,7 @@ use std::fs;
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
 use super::graphviz::write_mir_fn_graphviz;
-use transform::MirSource;
+use crate::transform::MirSource;
 
 const INDENT: &str = "    ";
 /// Alignment for lining up comments following MIR statements
@@ -69,7 +68,7 @@ pub fn dump_mir<'a, 'gcx, 'tcx, F>(
     pass_num: Option<&dyn Display>,
     pass_name: &str,
     disambiguator: &dyn Display,
-    source: MirSource,
+    source: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     extra_data: F,
 ) where
@@ -81,7 +80,7 @@ pub fn dump_mir<'a, 'gcx, 'tcx, F>(
 
     let node_path = item_path::with_forced_impl_filename_line(|| {
         // see notes on #41697 below
-        tcx.item_path_str(source.def_id)
+        tcx.item_path_str(source.def_id())
     });
     dump_matched_mir_node(
         tcx,
@@ -98,7 +97,7 @@ pub fn dump_mir<'a, 'gcx, 'tcx, F>(
 pub fn dump_enabled<'a, 'gcx, 'tcx>(
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
     pass_name: &str,
-    source: MirSource,
+    source: MirSource<'tcx>,
 ) -> bool {
     let filters = match tcx.sess.opts.debugging_opts.dump_mir {
         None => return false,
@@ -106,7 +105,7 @@ pub fn dump_enabled<'a, 'gcx, 'tcx>(
     };
     let node_path = item_path::with_forced_impl_filename_line(|| {
         // see notes on #41697 below
-        tcx.item_path_str(source.def_id)
+        tcx.item_path_str(source.def_id())
     });
     filters.split('|').any(|or_filter| {
         or_filter.split('&').all(|and_filter| {
@@ -125,13 +124,13 @@ fn dump_matched_mir_node<'a, 'gcx, 'tcx, F>(
     pass_name: &str,
     node_path: &str,
     disambiguator: &dyn Display,
-    source: MirSource,
+    source: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     mut extra_data: F,
 ) where
     F: FnMut(PassWhere, &mut dyn Write) -> io::Result<()>,
 {
-    let _: io::Result<()> = try_block! {
+    let _: io::Result<()> = try {
         let mut file = create_dump_file(tcx, "mir", pass_num, pass_name, disambiguator, source)?;
         writeln!(file, "// MIR for `{}`", node_path)?;
         writeln!(file, "// source = {:?}", source)?;
@@ -148,10 +147,10 @@ fn dump_matched_mir_node<'a, 'gcx, 'tcx, F>(
     };
 
     if tcx.sess.opts.debugging_opts.dump_mir_graphviz {
-        let _: io::Result<()> = try_block! {
+        let _: io::Result<()> = try {
             let mut file =
                 create_dump_file(tcx, "dot", pass_num, pass_name, disambiguator, source)?;
-            write_mir_fn_graphviz(tcx, source.def_id, mir, &mut file)?;
+            write_mir_fn_graphviz(tcx, source.def_id(), mir, &mut file)?;
         };
     }
 }
@@ -165,7 +164,7 @@ fn dump_path(
     pass_num: Option<&dyn Display>,
     pass_name: &str,
     disambiguator: &dyn Display,
-    source: MirSource,
+    source: MirSource<'tcx>,
 ) -> PathBuf {
     let promotion_id = match source.promoted {
         Some(id) => format!("-{:?}", id),
@@ -184,13 +183,32 @@ fn dump_path(
     let mut file_path = PathBuf::new();
     file_path.push(Path::new(&tcx.sess.opts.debugging_opts.dump_mir_dir));
 
-    let item_name = tcx.hir()
-        .def_path(source.def_id)
+    let item_name = tcx
+        .def_path(source.def_id())
         .to_filename_friendly_no_crate();
+    // All drop shims have the same DefId, so we have to add the type
+    // to get unique file names.
+    let shim_disambiguator = match source.instance {
+        ty::InstanceDef::DropGlue(_, Some(ty)) => {
+            // Unfortunately, pretty-printed typed are not very filename-friendly.
+            // We dome some filtering.
+            let mut s = ".".to_owned();
+            s.extend(ty.to_string()
+                .chars()
+                .filter_map(|c| match c {
+                    ' ' => None,
+                    ':' | '<' | '>' => Some('_'),
+                    c => Some(c)
+                }));
+            s
+        }
+        _ => String::new(),
+    };
 
     let file_name = format!(
-        "rustc.{}{}{}.{}.{}.{}",
+        "rustc.{}{}{}{}.{}.{}.{}",
         item_name,
+        shim_disambiguator,
         promotion_id,
         pass_num,
         pass_name,
@@ -213,7 +231,7 @@ pub(crate) fn create_dump_file(
     pass_num: Option<&dyn Display>,
     pass_name: &str,
     disambiguator: &dyn Display,
-    source: MirSource,
+    source: MirSource<'tcx>,
 ) -> io::Result<fs::File> {
     let file_path = dump_path(tcx, extension, pass_num, pass_name, disambiguator, source);
     if let Some(parent) = file_path.parent() {
@@ -253,7 +271,7 @@ pub fn write_mir_pretty<'a, 'gcx, 'tcx>(
         for (i, mir) in mir.promoted.iter_enumerated() {
             writeln!(w, "")?;
             let src = MirSource {
-                def_id,
+                instance: ty::InstanceDef::Item(def_id),
                 promoted: Some(i),
             };
             write_mir_fn(tcx, src, mir, &mut |_, _| Ok(()), w)?;
@@ -264,7 +282,7 @@ pub fn write_mir_pretty<'a, 'gcx, 'tcx>(
 
 pub fn write_mir_fn<'a, 'gcx, 'tcx, F>(
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
-    src: MirSource,
+    src: MirSource<'tcx>,
     mir: &Mir<'tcx>,
     extra_data: &mut F,
     w: &mut dyn Write,
@@ -446,7 +464,7 @@ impl<'cx, 'gcx, 'tcx> Visitor<'tcx> for ExtraComments<'cx, 'gcx, 'tcx> {
     }
 }
 
-fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
+fn comment(tcx: TyCtxt<'_, '_, '_>, SourceInfo { span, scope }: SourceInfo) -> String {
     format!(
         "scope {} at {}",
         scope.index(),
@@ -458,8 +476,8 @@ fn comment(tcx: TyCtxt, SourceInfo { span, scope }: SourceInfo) -> String {
 ///
 /// Returns the total number of variables printed.
 fn write_scope_tree(
-    tcx: TyCtxt,
-    mir: &Mir,
+    tcx: TyCtxt<'_, '_, '_>,
+    mir: &Mir<'_>,
     scope_tree: &FxHashMap<SourceScope, Vec<SourceScope>>,
     w: &mut dyn Write,
     parent: SourceScope,
@@ -528,8 +546,8 @@ fn write_scope_tree(
 /// local variables (both user-defined bindings and compiler temporaries).
 pub fn write_mir_intro<'a, 'gcx, 'tcx>(
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
-    src: MirSource,
-    mir: &Mir,
+    src: MirSource<'tcx>,
+    mir: &Mir<'_>,
     w: &mut dyn Write,
 ) -> io::Result<()> {
     write_mir_sig(tcx, src, mir, w)?;
@@ -568,40 +586,52 @@ pub fn write_mir_intro<'a, 'gcx, 'tcx>(
     Ok(())
 }
 
-fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut dyn Write) -> io::Result<()> {
-    let id = tcx.hir().as_local_node_id(src.def_id).unwrap();
-    let body_owner_kind = tcx.hir().body_owner_kind(id);
-    match (body_owner_kind, src.promoted) {
-        (_, Some(i)) => write!(w, "{:?} in", i)?,
-        (hir::BodyOwnerKind::Fn, _) => write!(w, "fn")?,
-        (hir::BodyOwnerKind::Const, _) => write!(w, "const")?,
-        (hir::BodyOwnerKind::Static(hir::MutImmutable), _) => write!(w, "static")?,
-        (hir::BodyOwnerKind::Static(hir::MutMutable), _) => write!(w, "static mut")?,
+fn write_mir_sig(
+    tcx: TyCtxt<'_, '_, '_>,
+    src: MirSource<'tcx>,
+    mir: &Mir<'_>,
+    w: &mut dyn Write,
+) -> io::Result<()> {
+    use rustc::hir::def::Def;
+
+    trace!("write_mir_sig: {:?}", src.instance);
+    let descr = tcx.describe_def(src.def_id());
+    let is_function = match descr {
+        Some(Def::Fn(_)) | Some(Def::Method(_)) | Some(Def::StructCtor(..)) => true,
+        _ => tcx.is_closure(src.def_id()),
+    };
+    match (descr, src.promoted) {
+        (_, Some(i)) => write!(w, "{:?} in ", i)?,
+        (Some(Def::StructCtor(..)), _) => write!(w, "struct ")?,
+        (Some(Def::Const(_)), _)
+        | (Some(Def::AssociatedConst(_)), _) => write!(w, "const ")?,
+        (Some(Def::Static(_, /*is_mutbl*/false)), _) => write!(w, "static ")?,
+        (Some(Def::Static(_, /*is_mutbl*/true)), _) => write!(w, "static mut ")?,
+        (_, _) if is_function => write!(w, "fn ")?,
+        (None, _) => {}, // things like anon const, not an item
+        _ => bug!("Unexpected def description {:?}", descr),
     }
 
     item_path::with_forced_impl_filename_line(|| {
         // see notes on #41697 elsewhere
-        write!(w, " {}", tcx.item_path_str(src.def_id))
+        write!(w, "{}", tcx.item_path_str(src.def_id()))
     })?;
 
-    match (body_owner_kind, src.promoted) {
-        (hir::BodyOwnerKind::Fn, None) => {
-            write!(w, "(")?;
+    if src.promoted.is_none() && is_function {
+        write!(w, "(")?;
 
-            // fn argument types.
-            for (i, arg) in mir.args_iter().enumerate() {
-                if i != 0 {
-                    write!(w, ", ")?;
-                }
-                write!(w, "{:?}: {}", Place::Local(arg), mir.local_decls[arg].ty)?;
+        // fn argument types.
+        for (i, arg) in mir.args_iter().enumerate() {
+            if i != 0 {
+                write!(w, ", ")?;
             }
-
-            write!(w, ") -> {}", mir.return_ty())?;
-        }
-        (hir::BodyOwnerKind::Const, _) | (hir::BodyOwnerKind::Static(_), _) | (_, Some(_)) => {
-            assert_eq!(mir.arg_count, 0);
-            write!(w, ": {} =", mir.return_ty())?;
+            write!(w, "{:?}: {}", Place::Local(arg), mir.local_decls[arg].ty)?;
         }
+
+        write!(w, ") -> {}", mir.return_ty())?;
+    } else {
+        assert_eq!(mir.arg_count, 0);
+        write!(w, ": {} =", mir.return_ty())?;
     }
 
     if let Some(yield_ty) = mir.yield_ty {
@@ -609,10 +639,13 @@ fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut dyn Write) -> i
         writeln!(w, "yields {}", yield_ty)?;
     }
 
+    write!(w, " ")?;
+    // Next thing that gets printed is the opening {
+
     Ok(())
 }
 
-fn write_temp_decls(mir: &Mir, w: &mut dyn Write) -> io::Result<()> {
+fn write_temp_decls(mir: &Mir<'_>, w: &mut dyn Write) -> io::Result<()> {
     // Compiler-introduced temporary types.
     for temp in mir.temps_iter() {
         writeln!(
@@ -628,12 +661,12 @@ fn write_temp_decls(mir: &Mir, w: &mut dyn Write) -> io::Result<()> {
     Ok(())
 }
 
-fn write_user_type_annotations(mir: &Mir, w: &mut dyn Write) -> io::Result<()> {
+fn write_user_type_annotations(mir: &Mir<'_>, w: &mut dyn Write) -> io::Result<()> {
     if !mir.user_type_annotations.is_empty() {
         writeln!(w, "| User Type Annotations")?;
     }
-    for (index, (span, annotation)) in mir.user_type_annotations.iter_enumerated() {
-        writeln!(w, "| {:?}: {:?} at {:?}", index.index(), annotation, span)?;
+    for (index, annotation) in mir.user_type_annotations.iter_enumerated() {
+        writeln!(w, "| {:?}: {:?} at {:?}", index.index(), annotation.user_ty, annotation.span)?;
     }
     if !mir.user_type_annotations.is_empty() {
         writeln!(w, "|")?;
@@ -641,7 +674,7 @@ fn write_user_type_annotations(mir: &Mir, w: &mut dyn Write) -> io::Result<()> {
     Ok(())
 }
 
-pub fn dump_mir_def_ids(tcx: TyCtxt, single: Option<DefId>) -> Vec<DefId> {
+pub fn dump_mir_def_ids(tcx: TyCtxt<'_, '_, '_>, single: Option<DefId>) -> Vec<DefId> {
     if let Some(i) = single {
         vec![i]
     } else {
diff --git a/src/librustc_msan/Cargo.toml b/src/librustc_msan/Cargo.toml
index 78c39d03e45a9..7d88aa59b3adb 100644
--- a/src/librustc_msan/Cargo.toml
+++ b/src/librustc_msan/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 build = "build.rs"
 name = "rustc_msan"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_msan"
diff --git a/src/librustc_msan/build.rs b/src/librustc_msan/build.rs
index e1140278f2b4e..1c66b0a9cd3cf 100644
--- a/src/librustc_msan/build.rs
+++ b/src/librustc_msan/build.rs
@@ -1,6 +1,3 @@
-extern crate build_helper;
-extern crate cmake;
-
 use std::env;
 use build_helper::sanitizer_lib_boilerplate;
 
@@ -8,6 +5,8 @@ use cmake::Config;
 
 fn main() {
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
+        build_helper::restore_library_path();
+
         let (native, target) = match sanitizer_lib_boilerplate("msan") {
             Ok(native) => native,
             _ => return,
diff --git a/src/librustc_msan/lib.rs b/src/librustc_msan/lib.rs
index d6c8e54c18db7..3bdb86d313dcb 100644
--- a/src/librustc_msan/lib.rs
+++ b/src/librustc_msan/lib.rs
@@ -6,3 +6,5 @@
 #![unstable(feature = "sanitizer_runtime_lib",
             reason = "internal implementation detail of sanitizers",
             issue = "0")]
+
+#![deny(rust_2018_idioms)]
diff --git a/src/librustc_passes/Cargo.toml b/src/librustc_passes/Cargo.toml
index 2babb93eedbcf..00bdcdc0cc021 100644
--- a/src/librustc_passes/Cargo.toml
+++ b/src/librustc_passes/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_passes"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_passes"
@@ -14,5 +15,6 @@ rustc = { path = "../librustc" }
 rustc_mir = { path = "../librustc_mir"}
 rustc_data_structures = { path = "../librustc_data_structures" }
 syntax = { path = "../libsyntax" }
+syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
diff --git a/src/librustc_passes/ast_validation.rs b/src/librustc_passes/ast_validation.rs
index 3d0e46d998622..606ae27412832 100644
--- a/src/librustc_passes/ast_validation.rs
+++ b/src/librustc_passes/ast_validation.rs
@@ -6,23 +6,94 @@
 // This pass is supposed to perform only simple checks not requiring name resolution
 // or type checking or some other kind of complex analysis.
 
+use std::mem;
+use syntax::print::pprust;
 use rustc::lint;
 use rustc::session::Session;
+use rustc_data_structures::fx::FxHashMap;
 use syntax::ast::*;
 use syntax::attr;
 use syntax::source_map::Spanned;
 use syntax::symbol::keywords;
 use syntax::ptr::P;
 use syntax::visit::{self, Visitor};
+use syntax::{span_err, struct_span_err, walk_list};
+use syntax_ext::proc_macro_decls::is_proc_macro_attr;
 use syntax_pos::Span;
-use errors;
 use errors::Applicability;
+use log::debug;
 
 struct AstValidator<'a> {
     session: &'a Session,
+    has_proc_macro_decls: bool,
+    has_global_allocator: bool,
+
+    // Used to ban nested `impl Trait`, e.g., `impl Into<impl Debug>`.
+    // Nested `impl Trait` _is_ allowed in associated type position,
+    // e.g `impl Iterator<Item=impl Debug>`
+    outer_impl_trait: Option<Span>,
+
+    // Used to ban `impl Trait` in path projections like `<impl Iterator>::Item`
+    // or `Foo::Bar<impl Trait>`
+    is_impl_trait_banned: bool,
 }
 
 impl<'a> AstValidator<'a> {
+    fn with_banned_impl_trait(&mut self, f: impl FnOnce(&mut Self)) {
+        let old = mem::replace(&mut self.is_impl_trait_banned, true);
+        f(self);
+        self.is_impl_trait_banned = old;
+    }
+
+    fn with_impl_trait(&mut self, outer_impl_trait: Option<Span>, f: impl FnOnce(&mut Self)) {
+        let old = mem::replace(&mut self.outer_impl_trait, outer_impl_trait);
+        f(self);
+        self.outer_impl_trait = old;
+    }
+
+    // Mirrors visit::walk_ty, but tracks relevant state
+    fn walk_ty(&mut self, t: &'a Ty) {
+        match t.node {
+            TyKind::ImplTrait(..) => {
+                self.with_impl_trait(Some(t.span), |this| visit::walk_ty(this, t))
+            }
+            TyKind::Path(ref qself, ref path) => {
+                // We allow these:
+                //  - `Option<impl Trait>`
+                //  - `option::Option<impl Trait>`
+                //  - `option::Option<T>::Foo<impl Trait>
+                //
+                // But not these:
+                //  - `<impl Trait>::Foo`
+                //  - `option::Option<impl Trait>::Foo`.
+                //
+                // To implement this, we disallow `impl Trait` from `qself`
+                // (for cases like `<impl Trait>::Foo>`)
+                // but we allow `impl Trait` in `GenericArgs`
+                // iff there are no more PathSegments.
+                if let Some(ref qself) = *qself {
+                    // `impl Trait` in `qself` is always illegal
+                    self.with_banned_impl_trait(|this| this.visit_ty(&qself.ty));
+                }
+
+                // Note that there should be a call to visit_path here,
+                // so if any logic is added to process `Path`s a call to it should be
+                // added both in visit_path and here. This code mirrors visit::walk_path.
+                for (i, segment) in path.segments.iter().enumerate() {
+                    // Allow `impl Trait` iff we're on the final path segment
+                    if i == path.segments.len() - 1 {
+                        self.visit_path_segment(path.span, segment);
+                    } else {
+                        self.with_banned_impl_trait(|this| {
+                            this.visit_path_segment(path.span, segment)
+                        });
+                    }
+                }
+            }
+            _ => visit::walk_ty(self, t),
+        }
+    }
+
     fn err_handler(&self) -> &errors::Handler {
         &self.session.diagnostic()
     }
@@ -110,21 +181,21 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    /// matches '-' lit | lit (cf. parser::Parser::parse_literal_maybe_minus),
-    /// or path for ranges.
-    ///
-    /// FIXME: do we want to allow expr -> pattern conversion to create path expressions?
-    /// That means making this work:
-    ///
-    /// ```rust,ignore (FIXME)
-    ///     struct S;
-    ///     macro_rules! m {
-    ///         ($a:expr) => {
-    ///             let $a = S;
-    ///         }
-    ///     }
-    ///     m!(S);
-    /// ```
+    /// Matches `'-' lit | lit (cf. parser::Parser::parse_literal_maybe_minus)`,
+    /// or paths for ranges.
+    //
+    // FIXME: do we want to allow `expr -> pattern` conversion to create path expressions?
+    // That means making this work:
+    //
+    // ```rust,ignore (FIXME)
+    // struct S;
+    // macro_rules! m {
+    //     ($a:expr) => {
+    //         let $a = S;
+    //     }
+    // }
+    // m!(S);
+    // ```
     fn check_expr_within_pat(&self, expr: &Expr, allow_paths: bool) {
         match expr.node {
             ExprKind::Lit(..) => {}
@@ -172,7 +243,7 @@ impl<'a> AstValidator<'a> {
             );
 
             if let Ok(snippet) = self.session.source_map().span_to_snippet(span) {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     span, "consider adding parentheses", format!("({})", snippet),
                     Applicability::MachineApplicable,
                 );
@@ -203,7 +274,74 @@ impl<'a> AstValidator<'a> {
             _ => None,
         }
     }
+}
 
+enum GenericPosition {
+    Param,
+    Arg,
+}
+
+fn validate_generics_order<'a>(
+    handler: &errors::Handler,
+    generics: impl Iterator<Item = (ParamKindOrd, Span, Option<String>)>,
+    pos: GenericPosition,
+    span: Span,
+) {
+    let mut max_param: Option<ParamKindOrd> = None;
+    let mut out_of_order = FxHashMap::default();
+    let mut param_idents = vec![];
+
+    for (kind, span, ident) in generics {
+        if let Some(ident) = ident {
+            param_idents.push((kind, param_idents.len(), ident));
+        }
+        let max_param = &mut max_param;
+        match max_param {
+            Some(max_param) if *max_param > kind => {
+                let entry = out_of_order.entry(kind).or_insert((*max_param, vec![]));
+                entry.1.push(span);
+            }
+            Some(_) | None => *max_param = Some(kind),
+        };
+    }
+
+    let mut ordered_params = "<".to_string();
+    if !out_of_order.is_empty() {
+        param_idents.sort_by_key(|&(po, i, _)| (po, i));
+        let mut first = true;
+        for (_, _, ident) in param_idents {
+            if !first {
+                ordered_params += ", ";
+            }
+            ordered_params += &ident;
+            first = false;
+        }
+    }
+    ordered_params += ">";
+
+    let pos_str = match pos {
+        GenericPosition::Param => "parameter",
+        GenericPosition::Arg => "argument",
+    };
+
+    for (param_ord, (max_param, spans)) in out_of_order {
+        let mut err = handler.struct_span_err(spans,
+            &format!(
+                "{} {pos}s must be declared prior to {} {pos}s",
+                param_ord,
+                max_param,
+                pos = pos_str,
+            ));
+        if let GenericPosition::Param = pos {
+            err.span_suggestion(
+                span,
+                &format!("reorder the {}s: lifetimes, then types, then consts", pos_str),
+                ordered_params.clone(),
+                Applicability::MachineApplicable,
+            );
+        }
+        err.emit();
+    }
 }
 
 impl<'a> Visitor<'a> for AstValidator<'a> {
@@ -225,7 +363,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 );
                 match val.node {
                     ExprKind::Lit(ref v) if v.node.is_numeric() => {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             place.span.between(val.span),
                             "if you meant to write a comparison against a negative value, add a \
                              space in between `<` and `-`",
@@ -267,6 +405,19 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 self.no_questions_in_bounds(bounds, "trait object types", false);
             }
             TyKind::ImplTrait(_, ref bounds) => {
+                if self.is_impl_trait_banned {
+                    struct_span_err!(self.session, ty.span, E0667,
+                        "`impl Trait` is not allowed in path parameters").emit();
+                }
+
+                if let Some(outer_impl_trait) = self.outer_impl_trait {
+                    struct_span_err!(self.session, ty.span, E0666,
+                                    "nested `impl Trait` is not allowed")
+                        .span_label(outer_impl_trait, "outer `impl Trait`")
+                        .span_label(ty.span, "nested `impl Trait` here")
+                        .emit();
+
+                }
                 if !bounds.iter()
                           .any(|b| if let GenericBound::Trait(..) = *b { true } else { false }) {
                     self.err_handler().span_err(ty.span, "at least one trait must be specified");
@@ -275,7 +426,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             _ => {}
         }
 
-        visit::walk_ty(self, ty)
+        self.walk_ty(ty)
     }
 
     fn visit_label(&mut self, label: &'a Label) {
@@ -289,6 +440,14 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     }
 
     fn visit_item(&mut self, item: &'a Item) {
+        if item.attrs.iter().any(|attr| is_proc_macro_attr(attr)  ) {
+            self.has_proc_macro_decls = true;
+        }
+
+        if attr::contains_name(&item.attrs, "global_allocator") {
+            self.has_global_allocator = true;
+        }
+
         match item.node {
             ItemKind::Impl(unsafety, polarity, _, _, Some(..), ref ty, ref impl_items) => {
                 self.invalid_visibility(&item.vis, None);
@@ -323,6 +482,26 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         .note("only trait implementations may be annotated with default").emit();
                 }
             }
+            ItemKind::Fn(_, header, ref generics, _) => {
+                // We currently do not permit const generics in `const fn`, as
+                // this is tantamount to allowing compile-time dependent typing.
+                if header.constness.node == Constness::Const {
+                    // Look for const generics and error if we find any.
+                    for param in &generics.params {
+                        match param.kind {
+                            GenericParamKind::Const { .. } => {
+                                self.err_handler()
+                                    .struct_span_err(
+                                        item.span,
+                                        "const parameters are not permitted in `const fn`",
+                                    )
+                                    .emit();
+                            }
+                            _ => {}
+                        }
+                    }
+                }
+            }
             ItemKind::ForeignMod(..) => {
                 self.invalid_visibility(
                     &item.vis,
@@ -414,28 +593,62 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         visit::walk_foreign_item(self, fi)
     }
 
+    // Mirrors visit::walk_generic_args, but tracks relevant state
+    fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
+        match *generic_args {
+            GenericArgs::AngleBracketed(ref data) => {
+                walk_list!(self, visit_generic_arg, &data.args);
+                validate_generics_order(self.err_handler(), data.args.iter().map(|arg| {
+                    (match arg {
+                        GenericArg::Lifetime(..) => ParamKindOrd::Lifetime,
+                        GenericArg::Type(..) => ParamKindOrd::Type,
+                        GenericArg::Const(..) => ParamKindOrd::Const,
+                    }, arg.span(), None)
+                }), GenericPosition::Arg, generic_args.span());
+                // Type bindings such as `Item=impl Debug` in `Iterator<Item=Debug>`
+                // are allowed to contain nested `impl Trait`.
+                self.with_impl_trait(None, |this| {
+                    walk_list!(this, visit_assoc_type_binding, &data.bindings);
+                });
+            }
+            GenericArgs::Parenthesized(ref data) => {
+                walk_list!(self, visit_ty, &data.inputs);
+                if let Some(ref type_) = data.output {
+                    // `-> Foo` syntax is essentially an associated type binding,
+                    // so it is also allowed to contain nested `impl Trait`.
+                    self.with_impl_trait(None, |this| this.visit_ty(type_));
+                }
+            }
+        }
+    }
+
     fn visit_generics(&mut self, generics: &'a Generics) {
-        let mut seen_non_lifetime_param = false;
-        let mut seen_default = None;
+        let mut prev_ty_default = None;
         for param in &generics.params {
-            match (&param.kind, seen_non_lifetime_param) {
-                (GenericParamKind::Lifetime { .. }, true) => {
+            if let GenericParamKind::Type { ref default, .. } = param.kind {
+                if default.is_some() {
+                    prev_ty_default = Some(param.ident.span);
+                } else if let Some(span) = prev_ty_default {
                     self.err_handler()
-                        .span_err(param.ident.span, "lifetime parameters must be leading");
-                },
-                (GenericParamKind::Lifetime { .. }, false) => {}
-                (GenericParamKind::Type { ref default, .. }, _) => {
-                    seen_non_lifetime_param = true;
-                    if default.is_some() {
-                        seen_default = Some(param.ident.span);
-                    } else if let Some(span) = seen_default {
-                        self.err_handler()
-                            .span_err(span, "type parameters with a default must be trailing");
-                        break;
-                    }
+                        .span_err(span, "type parameters with a default must be trailing");
+                    break;
                 }
             }
         }
+
+        validate_generics_order(self.err_handler(), generics.params.iter().map(|param| {
+            let span = param.ident.span;
+            let ident = Some(param.ident.to_string());
+            match &param.kind {
+                GenericParamKind::Lifetime { .. } => (ParamKindOrd::Lifetime, span, ident),
+                GenericParamKind::Type { .. } => (ParamKindOrd::Type, span, ident),
+                GenericParamKind::Const { ref ty } => {
+                    let ty = pprust::ty_to_string(ty);
+                    (ParamKindOrd::Const, span, Some(format!("const {}: {}", param.ident, ty)))
+                }
+            }
+        }), GenericPosition::Param, generics.span);
+
         for predicate in &generics.where_clause.predicates {
             if let WherePredicate::EqPredicate(ref predicate) = *predicate {
                 self.err_handler()
@@ -443,6 +656,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                                                supported in where clauses (see #20041)");
             }
         }
+
         visit::walk_generics(self, generics)
     }
 
@@ -490,148 +704,15 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     }
 }
 
-// Bans nested `impl Trait`, e.g., `impl Into<impl Debug>`.
-// Nested `impl Trait` _is_ allowed in associated type position,
-// e.g `impl Iterator<Item=impl Debug>`
-struct NestedImplTraitVisitor<'a> {
-    session: &'a Session,
-    outer_impl_trait: Option<Span>,
-}
-
-impl<'a> NestedImplTraitVisitor<'a> {
-    fn with_impl_trait<F>(&mut self, outer_impl_trait: Option<Span>, f: F)
-        where F: FnOnce(&mut NestedImplTraitVisitor<'a>)
-    {
-        let old_outer_impl_trait = self.outer_impl_trait;
-        self.outer_impl_trait = outer_impl_trait;
-        f(self);
-        self.outer_impl_trait = old_outer_impl_trait;
-    }
-}
-
-
-impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
-    fn visit_ty(&mut self, t: &'a Ty) {
-        if let TyKind::ImplTrait(..) = t.node {
-            if let Some(outer_impl_trait) = self.outer_impl_trait {
-                struct_span_err!(self.session, t.span, E0666,
-                                 "nested `impl Trait` is not allowed")
-                    .span_label(outer_impl_trait, "outer `impl Trait`")
-                    .span_label(t.span, "nested `impl Trait` here")
-                    .emit();
-
-            }
-            self.with_impl_trait(Some(t.span), |this| visit::walk_ty(this, t));
-        } else {
-            visit::walk_ty(self, t);
-        }
-    }
-    fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
-        match *generic_args {
-            GenericArgs::AngleBracketed(ref data) => {
-                for arg in &data.args {
-                    self.visit_generic_arg(arg)
-                }
-                for type_binding in &data.bindings {
-                    // Type bindings such as `Item=impl Debug` in `Iterator<Item=Debug>`
-                    // are allowed to contain nested `impl Trait`.
-                    self.with_impl_trait(None, |this| visit::walk_ty(this, &type_binding.ty));
-                }
-            }
-            GenericArgs::Parenthesized(ref data) => {
-                for type_ in &data.inputs {
-                    self.visit_ty(type_);
-                }
-                if let Some(ref type_) = data.output {
-                    // `-> Foo` syntax is essentially an associated type binding,
-                    // so it is also allowed to contain nested `impl Trait`.
-                    self.with_impl_trait(None, |this| visit::walk_ty(this, type_));
-                }
-            }
-        }
-    }
-
-    fn visit_mac(&mut self, _mac: &Spanned<Mac_>) {
-        // covered in AstValidator
-    }
-}
-
-// Bans `impl Trait` in path projections like `<impl Iterator>::Item` or `Foo::Bar<impl Trait>`.
-struct ImplTraitProjectionVisitor<'a> {
-    session: &'a Session,
-    is_banned: bool,
-}
-
-impl<'a> ImplTraitProjectionVisitor<'a> {
-    fn with_ban<F>(&mut self, f: F)
-        where F: FnOnce(&mut ImplTraitProjectionVisitor<'a>)
-    {
-        let old_is_banned = self.is_banned;
-        self.is_banned = true;
-        f(self);
-        self.is_banned = old_is_banned;
-    }
-}
-
-impl<'a> Visitor<'a> for ImplTraitProjectionVisitor<'a> {
-    fn visit_ty(&mut self, t: &'a Ty) {
-        match t.node {
-            TyKind::ImplTrait(..) => {
-                if self.is_banned {
-                    struct_span_err!(self.session, t.span, E0667,
-                        "`impl Trait` is not allowed in path parameters").emit();
-                }
-            }
-            TyKind::Path(ref qself, ref path) => {
-                // We allow these:
-                //  - `Option<impl Trait>`
-                //  - `option::Option<impl Trait>`
-                //  - `option::Option<T>::Foo<impl Trait>
-                //
-                // But not these:
-                //  - `<impl Trait>::Foo`
-                //  - `option::Option<impl Trait>::Foo`.
-                //
-                // To implement this, we disallow `impl Trait` from `qself`
-                // (for cases like `<impl Trait>::Foo>`)
-                // but we allow `impl Trait` in `GenericArgs`
-                // iff there are no more PathSegments.
-                if let Some(ref qself) = *qself {
-                    // `impl Trait` in `qself` is always illegal
-                    self.with_ban(|this| this.visit_ty(&qself.ty));
-                }
-
-                for (i, segment) in path.segments.iter().enumerate() {
-                    // Allow `impl Trait` iff we're on the final path segment
-                    if i == path.segments.len() - 1 {
-                        visit::walk_path_segment(self, path.span, segment);
-                    } else {
-                        self.with_ban(|this|
-                            visit::walk_path_segment(this, path.span, segment));
-                    }
-                }
-            }
-            _ => visit::walk_ty(self, t),
-        }
-    }
-
-    fn visit_mac(&mut self, _mac: &Spanned<Mac_>) {
-        // covered in AstValidator
-    }
-}
-
-pub fn check_crate(session: &Session, krate: &Crate) {
-    visit::walk_crate(
-        &mut NestedImplTraitVisitor {
-            session,
-            outer_impl_trait: None,
-        }, krate);
-
-    visit::walk_crate(
-        &mut ImplTraitProjectionVisitor {
-            session,
-            is_banned: false,
-        }, krate);
-
-    visit::walk_crate(&mut AstValidator { session }, krate)
+pub fn check_crate(session: &Session, krate: &Crate) -> (bool, bool) {
+    let mut validator = AstValidator {
+        session,
+        has_proc_macro_decls: false,
+        has_global_allocator: false,
+        outer_impl_trait: None,
+        is_impl_trait_banned: false,
+    };
+    visit::walk_crate(&mut validator, krate);
+
+    (validator.has_proc_macro_decls, validator.has_global_allocator)
 }
diff --git a/src/librustc_passes/diagnostics.rs b/src/librustc_passes/diagnostics.rs
index 037227aeb715d..19d4d3aeb0f65 100644
--- a/src/librustc_passes/diagnostics.rs
+++ b/src/librustc_passes/diagnostics.rs
@@ -1,5 +1,7 @@
 #![allow(non_snake_case)]
 
+use syntax::{register_diagnostic, register_diagnostics, register_long_diagnostics};
+
 register_long_diagnostics! {
 /*
 E0014: r##"
diff --git a/src/librustc_passes/hir_stats.rs b/src/librustc_passes/hir_stats.rs
index 604b31e7167a9..2427abad07c95 100644
--- a/src/librustc_passes/hir_stats.rs
+++ b/src/librustc_passes/hir_stats.rs
@@ -61,7 +61,7 @@ impl<'k> StatCollector<'k> {
         });
 
         entry.count += 1;
-        entry.size = ::std::mem::size_of_val(node);
+        entry.size = std::mem::size_of_val(node);
     }
 
     fn print(&self, title: &str) {
@@ -144,7 +144,7 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
     }
 
     fn visit_stmt(&mut self, s: &'v hir::Stmt) {
-        self.record("Stmt", Id::Node(s.node.id()), s);
+        self.record("Stmt", Id::Node(s.id), s);
         hir_visit::walk_stmt(self, s)
     }
 
@@ -158,11 +158,6 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
         hir_visit::walk_pat(self, p)
     }
 
-    fn visit_decl(&mut self, d: &'v hir::Decl) {
-        self.record("Decl", Id::None, d);
-        hir_visit::walk_decl(self, d)
-    }
-
     fn visit_expr(&mut self, ex: &'v hir::Expr) {
         self.record("Expr", Id::Node(ex.id), ex);
         hir_visit::walk_expr(self, ex)
diff --git a/src/librustc_passes/layout_test.rs b/src/librustc_passes/layout_test.rs
new file mode 100644
index 0000000000000..d21707c578b2a
--- /dev/null
+++ b/src/librustc_passes/layout_test.rs
@@ -0,0 +1,132 @@
+use rustc::hir;
+use rustc::hir::def_id::DefId;
+use rustc::hir::itemlikevisit::ItemLikeVisitor;
+use rustc::hir::ItemKind;
+use rustc::ty::layout::HasDataLayout;
+use rustc::ty::layout::HasTyCtxt;
+use rustc::ty::layout::LayoutOf;
+use rustc::ty::layout::TargetDataLayout;
+use rustc::ty::layout::TyLayout;
+use rustc::ty::ParamEnv;
+use rustc::ty::Ty;
+use rustc::ty::TyCtxt;
+use syntax::ast::Attribute;
+
+pub fn test_layout<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
+    if tcx.features().rustc_attrs {
+        // if the `rustc_attrs` feature is not enabled, don't bother testing layout
+        tcx.hir()
+            .krate()
+            .visit_all_item_likes(&mut VarianceTest { tcx });
+    }
+}
+
+struct VarianceTest<'a, 'tcx: 'a> {
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
+}
+
+impl<'a, 'tcx> ItemLikeVisitor<'tcx> for VarianceTest<'a, 'tcx> {
+    fn visit_item(&mut self, item: &'tcx hir::Item) {
+        let item_def_id = self.tcx.hir().local_def_id(item.id);
+
+        if let ItemKind::Ty(..) = item.node {
+            for attr in self.tcx.get_attrs(item_def_id).iter() {
+                if attr.check_name("rustc_layout") {
+                    self.dump_layout_of(item_def_id, item, attr);
+                }
+            }
+        }
+    }
+
+    fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem) {}
+    fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem) {}
+}
+
+impl<'a, 'tcx> VarianceTest<'a, 'tcx> {
+    fn dump_layout_of(&self, item_def_id: DefId, item: &hir::Item, attr: &Attribute) {
+        let tcx = self.tcx;
+        let param_env = self.tcx.param_env(item_def_id);
+        let ty = self.tcx.type_of(item_def_id);
+        match self.tcx.layout_of(param_env.and(ty)) {
+            Ok(ty_layout) => {
+                // Check out the `#[rustc_layout(..)]` attribute to tell what to dump.
+                // The `..` are the names of fields to dump.
+                let meta_items = attr.meta_item_list().unwrap_or_default();
+                for meta_item in meta_items {
+                    let name = meta_item.word().map(|mi| mi.name().as_str());
+                    let name = name.as_ref().map(|s| &s[..]).unwrap_or("");
+
+                    match name {
+                        "abi" => {
+                            self.tcx
+                                .sess
+                                .span_err(item.span, &format!("abi: {:?}", ty_layout.abi));
+                        }
+
+                        "align" => {
+                            self.tcx
+                                .sess
+                                .span_err(item.span, &format!("align: {:?}", ty_layout.align));
+                        }
+
+                        "size" => {
+                            self.tcx
+                                .sess
+                                .span_err(item.span, &format!("size: {:?}", ty_layout.size));
+                        }
+
+                        "homogeneous_aggregate" => {
+                            self.tcx.sess.span_err(
+                                item.span,
+                                &format!(
+                                    "homogeneous_aggregate: {:?}",
+                                    ty_layout
+                                        .homogeneous_aggregate(&UnwrapLayoutCx { tcx, param_env }),
+                                ),
+                            );
+                        }
+
+                        _ => {
+                            self.tcx.sess.span_err(
+                                meta_item.span,
+                                &format!("unrecognized field name `{}`", name),
+                            );
+                        }
+                    }
+                }
+            }
+
+            Err(layout_error) => {
+                self.tcx
+                    .sess
+                    .span_err(item.span, &format!("layout error: {:?}", layout_error));
+            }
+        }
+    }
+}
+
+struct UnwrapLayoutCx<'me, 'tcx> {
+    tcx: TyCtxt<'me, 'tcx, 'tcx>,
+    param_env: ParamEnv<'tcx>,
+}
+
+impl<'me, 'tcx> LayoutOf for UnwrapLayoutCx<'me, 'tcx> {
+    type Ty = Ty<'tcx>;
+    type TyLayout = TyLayout<'tcx>;
+
+    fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
+        self.tcx.layout_of(self.param_env.and(ty)).unwrap()
+    }
+}
+
+impl<'me, 'tcx> HasTyCtxt<'tcx> for UnwrapLayoutCx<'me, 'tcx> {
+    fn tcx<'a>(&'a self) -> TyCtxt<'a, 'tcx, 'tcx> {
+        self.tcx
+    }
+}
+
+impl<'me, 'tcx> HasDataLayout for UnwrapLayoutCx<'me, 'tcx> {
+    fn data_layout(&self) -> &TargetDataLayout {
+        self.tcx.data_layout()
+    }
+}
diff --git a/src/librustc_passes/lib.rs b/src/librustc_passes/lib.rs
index 829d4b34cf779..ff2e345d08401 100644
--- a/src/librustc_passes/lib.rs
+++ b/src/librustc_passes/lib.rs
@@ -4,26 +4,17 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(nll)]
 #![feature(rustc_diagnostic_macros)]
 
 #![recursion_limit="256"]
 
-#[macro_use]
-extern crate rustc;
-extern crate rustc_mir;
-extern crate rustc_data_structures;
+#![deny(rust_2018_idioms)]
 
 #[macro_use]
-extern crate log;
-#[macro_use]
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc_errors as errors;
+extern crate rustc;
 
 use rustc::ty::query::Providers;
 
@@ -32,11 +23,12 @@ mod diagnostics;
 pub mod ast_validation;
 pub mod rvalue_promotion;
 pub mod hir_stats;
+pub mod layout_test;
 pub mod loops;
 
 __build_diagnostic_array! { librustc_passes, DIAGNOSTICS }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     rvalue_promotion::provide(providers);
     loops::provide(providers);
 }
diff --git a/src/librustc_passes/loops.rs b/src/librustc_passes/loops.rs
index 7d9165a82bc8f..533e043efa9d2 100644
--- a/src/librustc_passes/loops.rs
+++ b/src/librustc_passes/loops.rs
@@ -1,15 +1,15 @@
-use self::Context::*;
+use Context::*;
 
 use rustc::session::Session;
 
 use rustc::ty::query::Providers;
-use rustc::ty::query::queries;
 use rustc::ty::TyCtxt;
 use rustc::hir::def_id::DefId;
 use rustc::hir::map::Map;
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use rustc::hir::{self, Node, Destination};
 use syntax::ast;
+use syntax::struct_span_err;
 use syntax_pos::Span;
 use errors::Applicability;
 
@@ -48,7 +48,7 @@ struct CheckLoopVisitor<'a, 'hir: 'a> {
 
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &module in tcx.hir().krate().modules.keys() {
-        queries::check_mod_loops::ensure(tcx, tcx.hir().local_def_id(module));
+        tcx.ensure().check_mod_loops(tcx.hir().local_def_id(module));
     }
 }
 
@@ -60,7 +60,7 @@ fn check_mod_loops<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
     }.as_deep_visitor());
 }
 
-pub(crate) fn provide(providers: &mut Providers) {
+pub(crate) fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         check_mod_loops,
         ..*providers
@@ -140,7 +140,7 @@ impl<'a, 'hir> Visitor<'hir> for CheckLoopVisitor<'a, 'hir> {
                                 .span_label(e.span,
                                             "can only break with a value inside \
                                             `loop` or breakable block")
-                                .span_suggestion_with_applicability(
+                                .span_suggestion(
                                     e.span,
                                     &format!(
                                         "instead, use `break` on its own \
diff --git a/src/librustc_passes/rvalue_promotion.rs b/src/librustc_passes/rvalue_promotion.rs
index f0b559f80a28c..20f31b3ebc173 100644
--- a/src/librustc_passes/rvalue_promotion.rs
+++ b/src/librustc_passes/rvalue_promotion.rs
@@ -28,10 +28,11 @@ use rustc::hir;
 use rustc_data_structures::sync::Lrc;
 use syntax::ast;
 use syntax_pos::{Span, DUMMY_SP};
-use self::Promotability::*;
+use log::debug;
+use Promotability::*;
 use std::ops::{BitAnd, BitAndAssign, BitOr};
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         rvalue_promotable_map,
         const_is_rvalue_promotable_to_static,
@@ -44,7 +45,6 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
         let def_id = tcx.hir().body_owner_def_id(body_id);
         tcx.const_is_rvalue_promotable_to_static(def_id);
     }
-    tcx.sess.abort_if_errors();
 }
 
 fn const_is_rvalue_promotable_to_static<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -56,8 +56,7 @@ fn const_is_rvalue_promotable_to_static<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let node_id = tcx.hir().as_local_node_id(def_id)
         .expect("rvalue_promotable_map invoked with non-local def-id");
     let body_id = tcx.hir().body_owned_by(node_id);
-    let body_hir_id = tcx.hir().node_to_hir_id(body_id.node_id);
-    tcx.rvalue_promotable_map(def_id).contains(&body_hir_id.local_id)
+    tcx.rvalue_promotable_map(def_id).contains(&body_id.hir_id.local_id)
 }
 
 fn rvalue_promotable_map<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -160,11 +159,11 @@ impl<'a, 'gcx> CheckCrateVisitor<'a, 'gcx> {
     }
 
     /// While the `ExprUseVisitor` walks, we will identify which
-    /// expressions are borrowed, and insert their ids into this
+    /// expressions are borrowed, and insert their IDs into this
     /// table. Actually, we insert the "borrow-id", which is normally
-    /// the id of the expression being borrowed: but in the case of
+    /// the ID of the expression being borrowed: but in the case of
     /// `ref mut` borrows, the `id` of the pattern is
-    /// inserted. Therefore later we remove that entry from the table
+    /// inserted. Therefore, later we remove that entry from the table
     /// and transfer it over to the value being matched. This will
     /// then prevent said value from being promoted.
     fn remove_mut_rvalue_borrow(&mut self, pat: &hir::Pat) -> bool {
@@ -191,6 +190,7 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
         self.in_static = false;
 
         match self.tcx.hir().body_owner_kind(item_id) {
+            hir::BodyOwnerKind::Closure |
             hir::BodyOwnerKind::Fn => self.in_fn = true,
             hir::BodyOwnerKind::Static(_) => self.in_static = true,
             _ => {}
@@ -220,26 +220,22 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
 
     fn check_stmt(&mut self, stmt: &'tcx hir::Stmt) -> Promotability {
         match stmt.node {
-            hir::StmtKind::Decl(ref decl, _node_id) => {
-                match &decl.node {
-                    hir::DeclKind::Local(local) => {
-                        if self.remove_mut_rvalue_borrow(&local.pat) {
-                            if let Some(init) = &local.init {
-                                self.mut_rvalue_borrows.insert(init.id);
-                            }
-                        }
-
-                        if let Some(ref expr) = local.init {
-                            let _ = self.check_expr(&expr);
-                        }
-                        NotPromotable
+            hir::StmtKind::Local(ref local) => {
+                if self.remove_mut_rvalue_borrow(&local.pat) {
+                    if let Some(init) = &local.init {
+                        self.mut_rvalue_borrows.insert(init.id);
                     }
-                    // Item statements are allowed
-                    hir::DeclKind::Item(_) => Promotable
                 }
+
+                if let Some(ref expr) = local.init {
+                    let _ = self.check_expr(&expr);
+                }
+                NotPromotable
             }
-            hir::StmtKind::Expr(ref box_expr, _node_id) |
-            hir::StmtKind::Semi(ref box_expr, _node_id) => {
+            // Item statements are allowed
+            hir::StmtKind::Item(..) => Promotable,
+            hir::StmtKind::Expr(ref box_expr) |
+            hir::StmtKind::Semi(ref box_expr) => {
                 let _ = self.check_expr(box_expr);
                 NotPromotable
             }
@@ -247,7 +243,7 @@ impl<'a, 'tcx> CheckCrateVisitor<'a, 'tcx> {
     }
 
     fn check_expr(&mut self, ex: &'tcx hir::Expr) -> Promotability {
-        let node_ty = self.tables.node_id_to_type(ex.hir_id);
+        let node_ty = self.tables.node_type(ex.hir_id);
         let mut outer = check_expr_kind(self, ex, node_ty);
         outer &= check_adjustments(self, ex);
 
@@ -309,7 +305,7 @@ fn check_expr_kind<'a, 'tcx>(
             if v.tables.is_method_call(e) {
                 return NotPromotable;
             }
-            match v.tables.node_id_to_type(lhs.hir_id).sty {
+            match v.tables.node_type(lhs.hir_id).sty {
                 ty::RawPtr(_) | ty::FnPtr(..) => {
                     assert!(op.node == hir::BinOpKind::Eq || op.node == hir::BinOpKind::Ne ||
                             op.node == hir::BinOpKind::Le || op.node == hir::BinOpKind::Lt ||
@@ -591,7 +587,7 @@ fn check_expr_kind<'a, 'tcx>(
     ty_result & node_result
 }
 
-/// Check the adjustments of an expression
+/// Checks the adjustments of an expression.
 fn check_adjustments<'a, 'tcx>(
     v: &mut CheckCrateVisitor<'a, 'tcx>,
     e: &hir::Expr) -> Promotability {
@@ -625,7 +621,7 @@ impl<'a, 'gcx, 'tcx> euv::Delegate<'tcx> for CheckCrateVisitor<'a, 'gcx> {
     fn consume(&mut self,
                _consume_id: ast::NodeId,
                _consume_span: Span,
-               _cmt: &mc::cmt_,
+               _cmt: &mc::cmt_<'_>,
                _mode: euv::ConsumeMode) {}
 
     fn borrow(&mut self,
@@ -684,11 +680,14 @@ impl<'a, 'gcx, 'tcx> euv::Delegate<'tcx> for CheckCrateVisitor<'a, 'gcx> {
     fn mutate(&mut self,
               _assignment_id: ast::NodeId,
               _assignment_span: Span,
-              _assignee_cmt: &mc::cmt_,
+              _assignee_cmt: &mc::cmt_<'_>,
               _mode: euv::MutateMode) {
     }
 
-    fn matched_pat(&mut self, _: &hir::Pat, _: &mc::cmt_, _: euv::MatchMode) {}
+    fn matched_pat(&mut self, _: &hir::Pat, _: &mc::cmt_<'_>, _: euv::MatchMode) {}
 
-    fn consume_pat(&mut self, _consume_pat: &hir::Pat, _cmt: &mc::cmt_, _mode: euv::ConsumeMode) {}
+    fn consume_pat(&mut self,
+                   _consume_pat: &hir::Pat,
+                   _cmt: &mc::cmt_<'_>,
+                   _mode: euv::ConsumeMode) {}
 }
diff --git a/src/librustc_plugin/Cargo.toml b/src/librustc_plugin/Cargo.toml
index d8fa1da1ce219..5e23aa0d7f74e 100644
--- a/src/librustc_plugin/Cargo.toml
+++ b/src/librustc_plugin/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 name = "rustc_plugin"
 version = "0.0.0"
 build = false
+edition = "2018"
 
 [lib]
 name = "rustc_plugin"
diff --git a/src/librustc_plugin/build.rs b/src/librustc_plugin/build.rs
index 46c452668c3c8..c1ba4d7b3d867 100644
--- a/src/librustc_plugin/build.rs
+++ b/src/librustc_plugin/build.rs
@@ -30,7 +30,7 @@ impl<'v> ItemLikeVisitor<'v> for RegistrarFinder {
     }
 }
 
-/// Find the function marked with `#[plugin_registrar]`, if any.
+/// Finds the function marked with `#[plugin_registrar]`, if any.
 pub fn find_plugin_registrar<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) -> Option<DefId> {
     tcx.plugin_registrar_fn(LOCAL_CRATE)
 }
diff --git a/src/librustc_plugin/diagnostics.rs b/src/librustc_plugin/diagnostics.rs
index 382a1edb43c4a..68462bd83ef60 100644
--- a/src/librustc_plugin/diagnostics.rs
+++ b/src/librustc_plugin/diagnostics.rs
@@ -1,5 +1,7 @@
 #![allow(non_snake_case)]
 
+use syntax::{register_diagnostic, register_diagnostics, register_long_diagnostics};
+
 register_long_diagnostics! {
 
 }
diff --git a/src/librustc_plugin/lib.rs b/src/librustc_plugin/lib.rs
index 7bdeae3e97854..351ba7f04d3b1 100644
--- a/src/librustc_plugin/lib.rs
+++ b/src/librustc_plugin/lib.rs
@@ -4,7 +4,7 @@
 //! in various ways.
 //!
 //! Plugin authors will use the `Registry` type re-exported by
-//! this module, along with its methods.  The rest of the module
+//! this module, along with its methods. The rest of the module
 //! is for use by `rustc` itself.
 //!
 //! To define a plugin, build a dylib crate with a
@@ -50,23 +50,16 @@
 //! See the [`plugin` feature](../unstable-book/language-features/plugin.html) of
 //! the Unstable Book for more examples.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(nll)]
 #![feature(rustc_diagnostic_macros)]
 
 #![recursion_limit="256"]
 
-#[macro_use] extern crate syntax;
+#![deny(rust_2018_idioms)]
 
-extern crate rustc;
-extern crate rustc_metadata;
-extern crate syntax_pos;
-extern crate rustc_errors as errors;
-
-pub use self::registry::Registry;
+pub use registry::Registry;
 
 mod diagnostics;
 pub mod registry;
diff --git a/src/librustc_plugin/load.rs b/src/librustc_plugin/load.rs
index 39f580420cf03..1b88cf05f40d5 100644
--- a/src/librustc_plugin/load.rs
+++ b/src/librustc_plugin/load.rs
@@ -3,18 +3,19 @@
 use rustc::session::Session;
 use rustc_metadata::creader::CrateLoader;
 use rustc_metadata::cstore::CStore;
-use registry::Registry;
+use crate::registry::Registry;
 
 use std::borrow::ToOwned;
 use std::env;
 use std::mem;
 use std::path::PathBuf;
 use syntax::ast;
+use syntax::span_err;
 use syntax_pos::{Span, DUMMY_SP};
 
 /// Pointer to a registrar function.
 pub type PluginRegistrarFun =
-    fn(&mut Registry);
+    fn(&mut Registry<'_>);
 
 pub struct PluginRegistrar {
     pub fun: PluginRegistrarFun,
diff --git a/src/librustc_plugin/registry.rs b/src/librustc_plugin/registry.rs
index b53d956a9c032..5c5b6f232b271 100644
--- a/src/librustc_plugin/registry.rs
+++ b/src/librustc_plugin/registry.rs
@@ -68,7 +68,7 @@ impl<'a> Registry<'a> {
         }
     }
 
-    /// Get the plugin's arguments, if any.
+    /// Gets the plugin's arguments, if any.
     ///
     /// These are specified inside the `plugin` crate attribute as
     ///
@@ -110,8 +110,8 @@ impl<'a> Registry<'a> {
                     edition,
                 }
             }
-            IdentTT(ext, _, allow_internal_unstable) => {
-                IdentTT(ext, Some(self.krate_span), allow_internal_unstable)
+            IdentTT { expander, span: _, allow_internal_unstable } => {
+                IdentTT { expander, span: Some(self.krate_span), allow_internal_unstable }
             }
             _ => extension,
         }));
@@ -126,7 +126,7 @@ impl<'a> Registry<'a> {
         self.register_syntax_extension(Symbol::intern(name), NormalTT {
             expander: Box::new(expander),
             def_info: None,
-            allow_internal_unstable: false,
+            allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
             unstable_feature: None,
diff --git a/src/librustc_privacy/Cargo.toml b/src/librustc_privacy/Cargo.toml
index 62eab40f3ec9a..5bf8024c56911 100644
--- a/src/librustc_privacy/Cargo.toml
+++ b/src/librustc_privacy/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_privacy"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_privacy"
@@ -13,4 +14,5 @@ rustc = { path = "../librustc" }
 rustc_typeck = { path = "../librustc_typeck" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_data_structures = { path = "../librustc_data_structures" }
\ No newline at end of file
+rustc_data_structures = { path = "../librustc_data_structures" }
+log = "0.4"
diff --git a/src/librustc_privacy/lib.rs b/src/librustc_privacy/lib.rs
index 4890369e13f20..91651ad29dfa4 100644
--- a/src/librustc_privacy/lib.rs
+++ b/src/librustc_privacy/lib.rs
@@ -1,19 +1,16 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+
+#![deny(rust_2018_idioms)]
 
 #![feature(nll)]
 #![feature(rustc_diagnostic_macros)]
 
 #![recursion_limit="256"]
 
-#[macro_use] extern crate rustc;
 #[macro_use] extern crate syntax;
-extern crate rustc_typeck;
-extern crate syntax_pos;
-extern crate rustc_data_structures;
 
-use rustc::hir::{self, Node, PatKind};
+use rustc::bug;
+use rustc::hir::{self, Node, PatKind, AssociatedItemKind};
 use rustc::hir::def::Def;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, CrateNum, DefId};
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
@@ -27,7 +24,7 @@ use rustc::ty::subst::Substs;
 use rustc::util::nodemap::NodeSet;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
-use syntax::ast::{self, CRATE_NODE_ID, Ident};
+use syntax::ast::{self, DUMMY_NODE_ID, Ident};
 use syntax::attr;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
@@ -44,9 +41,9 @@ mod diagnostics;
 /// Implemented to visit all `DefId`s in a type.
 /// Visiting `DefId`s is useful because visibilities and reachabilities are attached to them.
 /// The idea is to visit "all components of a type", as documented in
-/// https://github.com/rust-lang/rfcs/blob/master/text/2145-type-privacy.md#how-to-determine-visibility-of-a-type
-/// Default type visitor (`TypeVisitor`) does most of the job, but it has some shortcomings.
-/// First, it doesn't have overridable `fn visit_trait_ref`, so we have to catch trait def-ids
+/// https://github.com/rust-lang/rfcs/blob/master/text/2145-type-privacy.md#how-to-determine-visibility-of-a-type.
+/// The default type visitor (`TypeVisitor`) does most of the job, but it has some shortcomings.
+/// First, it doesn't have overridable `fn visit_trait_ref`, so we have to catch trait `DefId`s
 /// manually. Second, it doesn't visit some type components like signatures of fn types, or traits
 /// in `impl Trait`, see individual comments in `DefIdVisitorSkeleton::visit_ty`.
 trait DefIdVisitor<'a, 'tcx: 'a> {
@@ -390,7 +387,7 @@ impl VisibilityLike for Option<AccessLevel> {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-/// The embargo visitor, used to determine the exports of the ast
+/// The embargo visitor, used to determine the exports of the AST.
 ////////////////////////////////////////////////////////////////////////////////
 
 struct EmbargoVisitor<'a, 'tcx: 'a> {
@@ -436,6 +433,43 @@ impl<'a, 'tcx> EmbargoVisitor<'a, 'tcx> {
             ev: self,
         }
     }
+
+
+    /// Given the path segments of a `ItemKind::Use`, then we need
+    /// to update the visibility of the intermediate use so that it isn't linted
+    /// by `unreachable_pub`.
+    ///
+    /// This isn't trivial as `path.def` has the `DefId` of the eventual target
+    /// of the use statement not of the next intermediate use statement.
+    ///
+    /// To do this, consider the last two segments of the path to our intermediate
+    /// use statement. We expect the penultimate segment to be a module and the
+    /// last segment to be the name of the item we are exporting. We can then
+    /// look at the items contained in the module for the use statement with that
+    /// name and update that item's visibility.
+    ///
+    /// FIXME: This solution won't work with glob imports and doesn't respect
+    /// namespaces. See <https://github.com/rust-lang/rust/pull/57922#discussion_r251234202>.
+    fn update_visibility_of_intermediate_use_statements(&mut self, segments: &[hir::PathSegment]) {
+        if let Some([module, segment]) = segments.rchunks_exact(2).next() {
+            if let Some(item) = module.def
+                .and_then(|def| def.mod_def_id())
+                .and_then(|def_id| self.tcx.hir().as_local_node_id(def_id))
+                .map(|module_node_id| self.tcx.hir().expect_item(module_node_id))
+             {
+                if let hir::ItemKind::Mod(m) = &item.node {
+                    for item_id in m.item_ids.as_ref() {
+                        let item = self.tcx.hir().expect_item(item_id.id);
+                        let def_id = self.tcx.hir().local_def_id(item_id.id);
+                        if !self.tcx.hygienic_eq(segment.ident, item.ident, def_id) { continue; }
+                        if let hir::ItemKind::Use(..) = item.node {
+                            self.update(item.id, Some(AccessLevel::Exported));
+                        }
+                    }
+                }
+            }
+        }
+    }
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for EmbargoVisitor<'a, 'tcx> {
@@ -522,8 +556,14 @@ impl<'a, 'tcx> Visitor<'tcx> for EmbargoVisitor<'a, 'tcx> {
             hir::ItemKind::ExternCrate(..) => {}
             // All nested items are checked by `visit_item`.
             hir::ItemKind::Mod(..) => {}
-            // Re-exports are handled in `visit_mod`.
-            hir::ItemKind::Use(..) => {}
+            // Re-exports are handled in `visit_mod`. However, in order to avoid looping over
+            // all of the items of a mod in `visit_mod` looking for use statements, we handle
+            // making sure that intermediate use statements have their visibilities updated here.
+            hir::ItemKind::Use(ref path, _) => {
+                if item_level.is_some() {
+                    self.update_visibility_of_intermediate_use_statements(path.segments.as_ref());
+                }
+            }
             // The interface is empty.
             hir::ItemKind::GlobalAsm(..) => {}
             hir::ItemKind::Existential(..) => {
@@ -548,7 +588,7 @@ impl<'a, 'tcx> Visitor<'tcx> for EmbargoVisitor<'a, 'tcx> {
                         let mut reach = self.reach(trait_item_ref.id.node_id, item_level);
                         reach.generics().predicates();
 
-                        if trait_item_ref.kind == hir::AssociatedItemKind::Type &&
+                        if trait_item_ref.kind == AssociatedItemKind::Type &&
                            !trait_item_ref.defaultness.has_value() {
                             // No type to visit.
                         } else {
@@ -765,7 +805,8 @@ impl<'a, 'tcx> NamePrivacyVisitor<'a, 'tcx> {
                    def: &'tcx ty::AdtDef, // definition of the struct or enum
                    field: &'tcx ty::FieldDef) { // definition of the field
         let ident = Ident::new(keywords::Invalid.name(), use_ctxt);
-        let def_id = self.tcx.adjust_ident(ident, def.did, self.current_item).1;
+        let current_hir = self.tcx.hir().node_to_hir_id(self.current_item);
+        let def_id = self.tcx.adjust_ident(ident, def.did, current_hir).1;
         if !def.is_enum() && !field.vis.is_accessible_from(def_id, self.tcx) {
             struct_span_err!(self.tcx.sess, span, E0451, "field `{}` of {} `{}` is private",
                              field.ident, def.variant_descr(), self.tcx.item_path_str(def.did))
@@ -782,6 +823,11 @@ impl<'a, 'tcx> Visitor<'tcx> for NamePrivacyVisitor<'a, 'tcx> {
         NestedVisitorMap::All(&self.tcx.hir())
     }
 
+    fn visit_mod(&mut self, _m: &'tcx hir::Mod, _s: Span, _n: ast::NodeId) {
+        // Don't visit nested modules, since we run a separate visitor walk
+        // for each module in `privacy_access_levels`
+    }
+
     fn visit_nested_body(&mut self, body: hir::BodyId) {
         let orig_tables = mem::replace(&mut self.tables, self.tcx.body_tables(body));
         let body = self.tcx.hir().body(body);
@@ -888,7 +934,7 @@ impl<'a, 'tcx> TypePrivacyVisitor<'a, 'tcx> {
     // Take node-id of an expression or pattern and check its type for privacy.
     fn check_expr_pat_type(&mut self, id: hir::HirId, span: Span) -> bool {
         self.span = span;
-        if self.visit(self.tables.node_id_to_type(id)) || self.visit(self.tables.node_substs(id)) {
+        if self.visit(self.tables.node_type(id)) || self.visit(self.tables.node_substs(id)) {
             return true;
         }
         if let Some(adjustments) = self.tables.adjustments().get(id) {
@@ -917,6 +963,11 @@ impl<'a, 'tcx> Visitor<'tcx> for TypePrivacyVisitor<'a, 'tcx> {
         NestedVisitorMap::All(&self.tcx.hir())
     }
 
+    fn visit_mod(&mut self, _m: &'tcx hir::Mod, _s: Span, _n: ast::NodeId) {
+        // Don't visit nested modules, since we run a separate visitor walk
+        // for each module in `privacy_access_levels`
+    }
+
     fn visit_nested_body(&mut self, body: hir::BodyId) {
         let orig_tables = mem::replace(&mut self.tables, self.tcx.body_tables(body));
         let orig_in_body = mem::replace(&mut self.in_body, true);
@@ -930,7 +981,7 @@ impl<'a, 'tcx> Visitor<'tcx> for TypePrivacyVisitor<'a, 'tcx> {
         self.span = hir_ty.span;
         if self.in_body {
             // Types in bodies.
-            if self.visit(self.tables.node_id_to_type(hir_ty.hir_id)) {
+            if self.visit(self.tables.node_type(hir_ty.hir_id)) {
                 return;
             }
         } else {
@@ -1333,11 +1384,11 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
                         if self.item_is_public(&impl_item_ref.id.node_id, &impl_item_ref.vis) {
                             let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
                             match impl_item_ref.kind {
-                                hir::AssociatedItemKind::Const => {
+                                AssociatedItemKind::Const => {
                                     found_pub_static = true;
                                     intravisit::walk_impl_item(self, impl_item);
                                 }
-                                hir::AssociatedItemKind::Method { has_self: false } => {
+                                AssociatedItemKind::Method { has_self: false } => {
                                     found_pub_static = true;
                                     intravisit::walk_impl_item(self, impl_item);
                                 }
@@ -1441,6 +1492,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ObsoleteVisiblePrivateTypesVisitor<'a, 'tcx> {
 
 struct SearchInterfaceForPrivateItemsVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
+    item_id: ast::NodeId,
     item_def_id: DefId,
     span: Span,
     /// The visitor checks that each component type is at least this visible.
@@ -1448,6 +1500,7 @@ struct SearchInterfaceForPrivateItemsVisitor<'a, 'tcx: 'a> {
     has_pub_restricted: bool,
     has_old_errors: bool,
     in_assoc_ty: bool,
+    private_crates: FxHashSet<CrateNum>
 }
 
 impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
@@ -1482,6 +1535,16 @@ impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
     }
 
     fn check_def_id(&mut self, def_id: DefId, kind: &str, descr: &dyn fmt::Display) -> bool {
+        if self.leaks_private_dep(def_id) {
+            self.tcx.lint_node(lint::builtin::EXPORTED_PRIVATE_DEPENDENCIES,
+                               self.item_id,
+                               self.span,
+                               &format!("{} `{}` from private dependency '{}' in public \
+                                         interface", kind, descr,
+                                         self.tcx.crate_name(def_id.krate)));
+
+        }
+
         let node_id = match self.tcx.hir().as_local_node_id(def_id) {
             Some(node_id) => node_id,
             None => return false,
@@ -1504,9 +1567,23 @@ impl<'a, 'tcx: 'a> SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
                 self.tcx.lint_node(lint::builtin::PRIVATE_IN_PUBLIC, node_id, self.span,
                                    &format!("{} (error {})", msg, err_code));
             }
+
         }
+
         false
     }
+
+    /// An item is 'leaked' from a private dependency if all
+    /// of the following are true:
+    /// 1. It's contained within a public type
+    /// 2. It comes from a private crate
+    fn leaks_private_dep(&self, item_id: DefId) -> bool {
+        let ret = self.required_visibility == ty::Visibility::Public &&
+            self.private_crates.contains(&item_id.krate);
+
+        log::debug!("leaks_private_dep(item_id={:?})={}", item_id, ret);
+        return ret;
+    }
 }
 
 impl<'a, 'tcx> DefIdVisitor<'a, 'tcx> for SearchInterfaceForPrivateItemsVisitor<'a, 'tcx> {
@@ -1520,6 +1597,7 @@ struct PrivateItemsInPublicInterfacesVisitor<'a, 'tcx: 'a> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     has_pub_restricted: bool,
     old_error_set: &'a NodeSet,
+    private_crates: FxHashSet<CrateNum>
 }
 
 impl<'a, 'tcx> PrivateItemsInPublicInterfacesVisitor<'a, 'tcx> {
@@ -1550,12 +1628,32 @@ impl<'a, 'tcx> PrivateItemsInPublicInterfacesVisitor<'a, 'tcx> {
 
         SearchInterfaceForPrivateItemsVisitor {
             tcx: self.tcx,
+            item_id,
             item_def_id: self.tcx.hir().local_def_id(item_id),
             span: self.tcx.hir().span(item_id),
             required_visibility,
             has_pub_restricted: self.has_pub_restricted,
             has_old_errors,
             in_assoc_ty: false,
+            private_crates: self.private_crates.clone()
+        }
+    }
+
+    fn check_trait_or_impl_item(&self, node_id: ast::NodeId, assoc_item_kind: AssociatedItemKind,
+                                defaultness: hir::Defaultness, vis: ty::Visibility) {
+        let mut check = self.check(node_id, vis);
+
+        let (check_ty, is_assoc_ty) = match assoc_item_kind {
+            AssociatedItemKind::Const | AssociatedItemKind::Method { .. } => (true, false),
+            AssociatedItemKind::Type => (defaultness.has_value(), true),
+            // `ty()` for existential types is the underlying type,
+            // it's not a part of interface, so we skip it.
+            AssociatedItemKind::Existential => (false, true),
+        };
+        check.in_assoc_ty = is_assoc_ty;
+        check.generics().predicates();
+        if check_ty {
+            check.ty();
         }
     }
 }
@@ -1592,16 +1690,8 @@ impl<'a, 'tcx> Visitor<'tcx> for PrivateItemsInPublicInterfacesVisitor<'a, 'tcx>
                 self.check(item.id, item_visibility).generics().predicates();
 
                 for trait_item_ref in trait_item_refs {
-                    let mut check = self.check(trait_item_ref.id.node_id, item_visibility);
-                    check.in_assoc_ty = trait_item_ref.kind == hir::AssociatedItemKind::Type;
-                    check.generics().predicates();
-
-                    if trait_item_ref.kind == hir::AssociatedItemKind::Type &&
-                       !trait_item_ref.defaultness.has_value() {
-                        // No type to visit.
-                    } else {
-                        check.ty();
-                    }
+                    self.check_trait_or_impl_item(trait_item_ref.id.node_id, trait_item_ref.kind,
+                                                  trait_item_ref.defaultness, item_visibility);
                 }
             }
             hir::ItemKind::TraitAlias(..) => {
@@ -1647,18 +1737,18 @@ impl<'a, 'tcx> Visitor<'tcx> for PrivateItemsInPublicInterfacesVisitor<'a, 'tcx>
                     } else {
                         impl_vis
                     };
-                    let mut check = self.check(impl_item.id, impl_item_vis);
-                    check.in_assoc_ty = impl_item_ref.kind == hir::AssociatedItemKind::Type;
-                    check.generics().predicates().ty();
+                    self.check_trait_or_impl_item(impl_item_ref.id.node_id, impl_item_ref.kind,
+                                                  impl_item_ref.defaultness, impl_item_vis);
                 }
             }
         }
     }
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         privacy_access_levels,
+        check_mod_privacy,
         ..*providers
     };
 }
@@ -1667,34 +1757,50 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Lrc<AccessLevels> {
     tcx.privacy_access_levels(LOCAL_CRATE)
 }
 
-fn privacy_access_levels<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                                   krate: CrateNum)
-                                   -> Lrc<AccessLevels> {
-    assert_eq!(krate, LOCAL_CRATE);
-
-    let krate = tcx.hir().krate();
+fn check_mod_privacy<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
     let empty_tables = ty::TypeckTables::empty(None);
 
+
     // Check privacy of names not checked in previous compilation stages.
     let mut visitor = NamePrivacyVisitor {
         tcx,
         tables: &empty_tables,
-        current_item: CRATE_NODE_ID,
+        current_item: DUMMY_NODE_ID,
         empty_tables: &empty_tables,
     };
-    intravisit::walk_crate(&mut visitor, krate);
+    let (module, span, node_id) = tcx.hir().get_module(module_def_id);
+    intravisit::walk_mod(&mut visitor, module, node_id);
 
     // Check privacy of explicitly written types and traits as well as
     // inferred types of expressions and patterns.
     let mut visitor = TypePrivacyVisitor {
         tcx,
         tables: &empty_tables,
-        current_item: DefId::local(CRATE_DEF_INDEX),
+        current_item: module_def_id,
         in_body: false,
-        span: krate.span,
+        span,
         empty_tables: &empty_tables,
     };
-    intravisit::walk_crate(&mut visitor, krate);
+    intravisit::walk_mod(&mut visitor, module, node_id);
+}
+
+fn privacy_access_levels<'tcx>(
+    tcx: TyCtxt<'_, 'tcx, 'tcx>,
+    krate: CrateNum,
+) -> Lrc<AccessLevels> {
+    assert_eq!(krate, LOCAL_CRATE);
+
+    let krate = tcx.hir().krate();
+
+    for &module in krate.modules.keys() {
+        tcx.ensure().check_mod_privacy(tcx.hir().local_def_id(module));
+    }
+
+    let private_crates: FxHashSet<CrateNum> = tcx.sess.opts.extern_private.iter()
+        .flat_map(|c| {
+            tcx.crates().iter().find(|&&krate| &tcx.crate_name(krate) == c).cloned()
+        }).collect();
+
 
     // Build up a set of all exported items in the AST. This is a set of all
     // items which are reachable from external crates based on visibility.
@@ -1738,6 +1844,7 @@ fn privacy_access_levels<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             tcx,
             has_pub_restricted,
             old_error_set: &visitor.old_error_set,
+            private_crates
         };
         krate.visit_all_item_likes(&mut DeepVisitor::new(&mut visitor));
     }
diff --git a/src/librustc_resolve/Cargo.toml b/src/librustc_resolve/Cargo.toml
index 3a8e84a3280c6..836b4ad38ca88 100644
--- a/src/librustc_resolve/Cargo.toml
+++ b/src/librustc_resolve/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_resolve"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_resolve"
@@ -15,7 +16,7 @@ log = "0.4"
 syntax = { path = "../libsyntax" }
 rustc = { path = "../librustc" }
 arena = { path = "../libarena" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 syntax_pos = { path = "../libsyntax_pos" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_metadata = { path = "../librustc_metadata" }
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index a452bbf0c9d54..a82f8df154725 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -1,16 +1,17 @@
-//! Reduced graph building
+//! Reduced graph building.
 //!
 //! Here we build the "reduced graph": the graph of the module tree without
 //! any imports resolved.
 
-use macros::{InvocationData, ParentScope, LegacyScope};
-use resolve_imports::ImportDirective;
-use resolve_imports::ImportDirectiveSubclass::{self, GlobImport, SingleImport};
-use {Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
-use {ModuleOrUniformRoot, PerNS, Resolver, ResolverArenas, ExternPreludeEntry};
-use Namespace::{self, TypeNS, ValueNS, MacroNS};
-use {resolve_error, resolve_struct_error, ResolutionError};
+use crate::macros::{InvocationData, ParentScope, LegacyScope};
+use crate::resolve_imports::ImportDirective;
+use crate::resolve_imports::ImportDirectiveSubclass::{self, GlobImport, SingleImport};
+use crate::{Module, ModuleData, ModuleKind, NameBinding, NameBindingKind, Segment, ToNameBinding};
+use crate::{ModuleOrUniformRoot, PerNS, Resolver, ResolverArenas, ExternPreludeEntry};
+use crate::Namespace::{self, TypeNS, ValueNS, MacroNS};
+use crate::{resolve_error, resolve_struct_error, ResolutionError};
 
+use rustc::bug;
 use rustc::hir::def::*;
 use rustc::hir::def_id::{CrateNum, CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
 use rustc::ty;
@@ -21,6 +22,8 @@ use std::cell::Cell;
 use std::ptr;
 use rustc_data_structures::sync::Lrc;
 
+use errors::Applicability;
+
 use syntax::ast::{Name, Ident};
 use syntax::attr;
 
@@ -30,14 +33,17 @@ use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::base::Determinacy::Undetermined;
 use syntax::ext::hygiene::Mark;
 use syntax::ext::tt::macro_rules;
-use syntax::feature_gate::{is_builtin_attr, emit_feature_err, GateIssue};
+use syntax::feature_gate::is_builtin_attr;
 use syntax::parse::token::{self, Token};
+use syntax::span_err;
 use syntax::std_inject::injected_crate_name;
 use syntax::symbol::keywords;
 use syntax::visit::{self, Visitor};
 
 use syntax_pos::{Span, DUMMY_SP};
 
+use log::debug;
+
 impl<'a> ToNameBinding<'a> for (Module<'a>, ty::Visibility, Span, Mark) {
     fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
         arenas.alloc_name_binding(NameBinding {
@@ -236,12 +242,14 @@ impl<'a> Resolver<'a> {
                         macro_ns: Cell::new(None),
                     },
                     type_ns_only,
+                    nested,
                 };
                 self.add_import_directive(
                     module_path,
                     subclass,
                     use_tree.span,
                     id,
+                    item,
                     root_span,
                     item.id,
                     vis,
@@ -258,6 +266,7 @@ impl<'a> Resolver<'a> {
                     subclass,
                     use_tree.span,
                     id,
+                    item,
                     root_span,
                     item.id,
                     vis,
@@ -345,14 +354,15 @@ impl<'a> Resolver<'a> {
                 let module = if orig_name.is_none() && ident.name == keywords::SelfLower.name() {
                     self.session
                         .struct_span_err(item.span, "`extern crate self;` requires renaming")
-                        .span_suggestion(item.span, "try", "extern crate self as name;".into())
+                        .span_suggestion(
+                            item.span,
+                            "try",
+                            "extern crate self as name;".into(),
+                            Applicability::HasPlaceholders,
+                        )
                         .emit();
                     return;
                 } else if orig_name == Some(keywords::SelfLower.name()) {
-                    if !self.session.features_untracked().extern_crate_self {
-                        emit_feature_err(&self.session.parse_sess, "extern_crate_self", item.span,
-                                         GateIssue::Language, "`extern crate self` is unstable");
-                    }
                     self.graph_root
                 } else {
                     let crate_id = self.crate_loader.process_extern_crate(item, &self.definitions);
@@ -376,6 +386,9 @@ impl<'a> Resolver<'a> {
                         source: orig_name,
                         target: ident,
                     },
+                    has_attributes: !item.attrs.is_empty(),
+                    use_span_with_attributes: item.span_with_attributes(),
+                    use_span: item.span,
                     root_span: item.span,
                     span: item.span,
                     module_path: Vec::new(),
@@ -673,6 +686,10 @@ impl<'a> Resolver<'a> {
                 }
                 module.populated.set(true);
             }
+            Def::Existential(..) |
+            Def::TraitAlias(..) => {
+                self.define(parent, ident, TypeNS, (def, vis, DUMMY_SP, expansion));
+            }
             Def::Struct(..) | Def::Union(..) => {
                 self.define(parent, ident, TypeNS, (def, vis, DUMMY_SP, expansion));
 
@@ -773,7 +790,7 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    // This returns true if we should consider the underlying `extern crate` to be used.
+    /// Returns `true` if we should consider the underlying `extern crate` to be used.
     fn process_legacy_macro_imports(&mut self, item: &Item, module: Module<'a>,
                                     parent_scope: &ParentScope<'a>) -> bool {
         let mut import_all = None;
@@ -817,6 +834,9 @@ impl<'a> Resolver<'a> {
             parent_scope: parent_scope.clone(),
             imported_module: Cell::new(Some(ModuleOrUniformRoot::Module(module))),
             subclass: ImportDirectiveSubclass::MacroUse,
+            use_span_with_attributes: item.span_with_attributes(),
+            has_attributes: !item.attrs.is_empty(),
+            use_span: item.span,
             root_span: span,
             span,
             module_path: Vec::new(),
@@ -856,7 +876,7 @@ impl<'a> Resolver<'a> {
         import_all.is_some() || !single_imports.is_empty()
     }
 
-    // does this attribute list contain "macro_use"?
+    /// Returns `true` if this attribute list contains `macro_use`.
     fn contains_macro_use(&mut self, attrs: &[ast::Attribute]) -> bool {
         for attr in attrs {
             if attr.check_name("macro_escape") {
diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs
index 16d8a95c003f7..3b6179f78558b 100644
--- a/src/librustc_resolve/check_unused.rs
+++ b/src/librustc_resolve/check_unused.rs
@@ -7,23 +7,52 @@
 //
 // Unused trait imports can't be checked until the method resolution. We save
 // candidates here, and do the actual check in librustc_typeck/check_unused.rs.
+//
+// Checking for unused imports is split into three steps:
+//
+//  - `UnusedImportCheckVisitor` walks the AST to find all the unused imports
+//    inside of `UseTree`s, recording their `NodeId`s and grouping them by
+//    the parent `use` item
+//
+//  - `calc_unused_spans` then walks over all the `use` items marked in the
+//    previous step to collect the spans associated with the `NodeId`s and to
+//    calculate the spans that can be removed by rustfix; This is done in a
+//    separate step to be able to collapse the adjacent spans that rustfix
+//    will remove
+//
+//  - `check_crate` finally emits the diagnostics based on the data generated
+//    in the last step
 
 use std::ops::{Deref, DerefMut};
 
-use Resolver;
-use resolve_imports::ImportDirectiveSubclass;
+use crate::Resolver;
+use crate::resolve_imports::ImportDirectiveSubclass;
 
-use rustc::{lint, ty};
 use rustc::util::nodemap::NodeMap;
+use rustc::{lint, ty};
+use rustc_data_structures::fx::FxHashSet;
 use syntax::ast;
 use syntax::visit::{self, Visitor};
 use syntax_pos::{Span, MultiSpan, DUMMY_SP};
 
+struct UnusedImport<'a> {
+    use_tree: &'a ast::UseTree,
+    use_tree_id: ast::NodeId,
+    item_span: Span,
+    unused: FxHashSet<ast::NodeId>,
+}
+
+impl<'a> UnusedImport<'a> {
+    fn add(&mut self, id: ast::NodeId) {
+        self.unused.insert(id);
+    }
+}
 
 struct UnusedImportCheckVisitor<'a, 'b: 'a> {
     resolver: &'a mut Resolver<'b>,
     /// All the (so far) unused imports, grouped path list
-    unused_imports: NodeMap<NodeMap<Span>>,
+    unused_imports: NodeMap<UnusedImport<'a>>,
+    base_use_tree: Option<&'a ast::UseTree>,
     base_id: ast::NodeId,
     item_span: Span,
 }
@@ -46,7 +75,7 @@ impl<'a, 'b> DerefMut for UnusedImportCheckVisitor<'a, 'b> {
 impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
     // We have information about whether `use` (import) directives are actually
     // used now. If an import is not used at all, we signal a lint error.
-    fn check_import(&mut self, item_id: ast::NodeId, id: ast::NodeId, span: Span) {
+    fn check_import(&mut self, id: ast::NodeId) {
         let mut used = false;
         self.per_ns(|this, ns| used |= this.used_imports.contains(&(id, ns)));
         if !used {
@@ -54,16 +83,31 @@ impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
                 // Check later.
                 return;
             }
-            self.unused_imports.entry(item_id).or_default().insert(id, span);
+            self.unused_import(self.base_id).add(id);
         } else {
             // This trait import is definitely used, in a way other than
             // method resolution.
             self.maybe_unused_trait_imports.remove(&id);
-            if let Some(i) = self.unused_imports.get_mut(&item_id) {
-                i.remove(&id);
+            if let Some(i) = self.unused_imports.get_mut(&self.base_id) {
+                i.unused.remove(&id);
             }
         }
     }
+
+    fn unused_import(&mut self, id: ast::NodeId) -> &mut UnusedImport<'a> {
+        let use_tree_id = self.base_id;
+        let use_tree = self.base_use_tree.unwrap();
+        let item_span = self.item_span;
+
+        self.unused_imports
+            .entry(id)
+            .or_insert_with(|| UnusedImport {
+                use_tree,
+                use_tree_id,
+                item_span,
+                unused: FxHashSet::default(),
+            })
+    }
 }
 
 impl<'a, 'b> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b> {
@@ -88,32 +132,113 @@ impl<'a, 'b> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b> {
         // This allows the grouping of all the lints in the same item
         if !nested {
             self.base_id = id;
+            self.base_use_tree = Some(use_tree);
         }
 
         if let ast::UseTreeKind::Nested(ref items) = use_tree.kind {
-            // If it's the parent group, cover the entire use item
-            let span = if nested {
-                use_tree.span
-            } else {
-                self.item_span
-            };
-
             if items.is_empty() {
-                self.unused_imports
-                    .entry(self.base_id)
-                    .or_default()
-                    .insert(id, span);
+                self.unused_import(self.base_id).add(id);
             }
         } else {
-            let base_id = self.base_id;
-            self.check_import(base_id, id, use_tree.span);
+            self.check_import(id);
         }
 
         visit::walk_use_tree(self, use_tree, id);
     }
 }
 
-pub fn check_crate(resolver: &mut Resolver, krate: &ast::Crate) {
+enum UnusedSpanResult {
+    Used,
+    FlatUnused(Span, Span),
+    NestedFullUnused(Vec<Span>, Span),
+    NestedPartialUnused(Vec<Span>, Vec<Span>),
+}
+
+fn calc_unused_spans(
+    unused_import: &UnusedImport<'_>,
+    use_tree: &ast::UseTree,
+    use_tree_id: ast::NodeId,
+) -> UnusedSpanResult {
+    // The full span is the whole item's span if this current tree is not nested inside another
+    // This tells rustfix to remove the whole item if all the imports are unused
+    let full_span = if unused_import.use_tree.span == use_tree.span {
+        unused_import.item_span
+    } else {
+        use_tree.span
+    };
+    match use_tree.kind {
+        ast::UseTreeKind::Simple(..) | ast::UseTreeKind::Glob => {
+            if unused_import.unused.contains(&use_tree_id) {
+                UnusedSpanResult::FlatUnused(use_tree.span, full_span)
+            } else {
+                UnusedSpanResult::Used
+            }
+        }
+        ast::UseTreeKind::Nested(ref nested) => {
+            if nested.len() == 0 {
+                return UnusedSpanResult::FlatUnused(use_tree.span, full_span);
+            }
+
+            let mut unused_spans = Vec::new();
+            let mut to_remove = Vec::new();
+            let mut all_nested_unused = true;
+            let mut previous_unused = false;
+            for (pos, (use_tree, use_tree_id)) in nested.iter().enumerate() {
+                let remove = match calc_unused_spans(unused_import, use_tree, *use_tree_id) {
+                    UnusedSpanResult::Used => {
+                        all_nested_unused = false;
+                        None
+                    }
+                    UnusedSpanResult::FlatUnused(span, remove) => {
+                        unused_spans.push(span);
+                        Some(remove)
+                    }
+                    UnusedSpanResult::NestedFullUnused(mut spans, remove) => {
+                        unused_spans.append(&mut spans);
+                        Some(remove)
+                    }
+                    UnusedSpanResult::NestedPartialUnused(mut spans, mut to_remove_extra) => {
+                        all_nested_unused = false;
+                        unused_spans.append(&mut spans);
+                        to_remove.append(&mut to_remove_extra);
+                        None
+                    }
+                };
+                if let Some(remove) = remove {
+                    let remove_span = if nested.len() == 1 {
+                        remove
+                    } else if pos == nested.len() - 1 || !all_nested_unused {
+                        // Delete everything from the end of the last import, to delete the
+                        // previous comma
+                        nested[pos - 1].0.span.shrink_to_hi().to(use_tree.span)
+                    } else {
+                        // Delete everything until the next import, to delete the trailing commas
+                        use_tree.span.to(nested[pos + 1].0.span.shrink_to_lo())
+                    };
+
+                    // Try to collapse adjacent spans into a single one. This prevents all cases of
+                    // overlapping removals, which are not supported by rustfix
+                    if previous_unused && !to_remove.is_empty() {
+                        let previous = to_remove.pop().unwrap();
+                        to_remove.push(previous.to(remove_span));
+                    } else {
+                        to_remove.push(remove_span);
+                    }
+                }
+                previous_unused = remove.is_some();
+            }
+            if unused_spans.is_empty() {
+                UnusedSpanResult::Used
+            } else if all_nested_unused {
+                UnusedSpanResult::NestedFullUnused(unused_spans, full_span)
+            } else {
+                UnusedSpanResult::NestedPartialUnused(unused_spans, to_remove)
+            }
+        }
+    }
+}
+
+pub fn check_crate(resolver: &mut Resolver<'_>, krate: &ast::Crate) {
     for directive in resolver.potentially_unused_imports.iter() {
         match directive.subclass {
             _ if directive.used.get() ||
@@ -152,14 +277,33 @@ pub fn check_crate(resolver: &mut Resolver, krate: &ast::Crate) {
     let mut visitor = UnusedImportCheckVisitor {
         resolver,
         unused_imports: Default::default(),
+        base_use_tree: None,
         base_id: ast::DUMMY_NODE_ID,
         item_span: DUMMY_SP,
     };
     visit::walk_crate(&mut visitor, krate);
 
-    for (id, spans) in &visitor.unused_imports {
+    for unused in visitor.unused_imports.values() {
+        let mut fixes = Vec::new();
+        let mut spans = match calc_unused_spans(unused, unused.use_tree, unused.use_tree_id) {
+            UnusedSpanResult::Used => continue,
+            UnusedSpanResult::FlatUnused(span, remove) => {
+                fixes.push((remove, String::new()));
+                vec![span]
+            }
+            UnusedSpanResult::NestedFullUnused(spans, remove) => {
+                fixes.push((remove, String::new()));
+                spans
+            }
+            UnusedSpanResult::NestedPartialUnused(spans, remove) => {
+                for fix in &remove {
+                    fixes.push((*fix, String::new()));
+                }
+                spans
+            }
+        };
+
         let len = spans.len();
-        let mut spans = spans.values().cloned().collect::<Vec<Span>>();
         spans.sort();
         let ms = MultiSpan::from_spans(spans.clone());
         let mut span_snippets = spans.iter()
@@ -177,6 +321,21 @@ pub fn check_crate(resolver: &mut Resolver, krate: &ast::Crate) {
                           } else {
                               String::new()
                           });
-        visitor.session.buffer_lint(lint::builtin::UNUSED_IMPORTS, *id, ms, &msg);
+
+        let fix_msg = if fixes.len() == 1 && fixes[0].0 == unused.item_span {
+            "remove the whole `use` item"
+        } else if spans.len() > 1 {
+            "remove the unused imports"
+        } else {
+            "remove the unused import"
+        };
+
+        visitor.session.buffer_lint_with_diagnostic(
+            lint::builtin::UNUSED_IMPORTS,
+            unused.use_tree_id,
+            ms,
+            &msg,
+            lint::builtin::BuiltinLintDiagnostics::UnusedImports(fix_msg.into(), fixes),
+        );
     }
 }
diff --git a/src/librustc_resolve/diagnostics.rs b/src/librustc_resolve/diagnostics.rs
index 3f9c5f4fd273c..5c095994a1bbd 100644
--- a/src/librustc_resolve/diagnostics.rs
+++ b/src/librustc_resolve/diagnostics.rs
@@ -1,5 +1,7 @@
 #![allow(non_snake_case)]
 
+use syntax::{register_diagnostic, register_diagnostics, register_long_diagnostics};
+
 // Error messages for EXXXX errors.  Each message should start and end with a
 // new line, and be wrapped to 80 characters.  In vim you can `:set tw=80` and
 // use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
@@ -412,8 +414,8 @@ https://doc.rust-lang.org/reference.html#use-declarations
 "##,
 
 E0401: r##"
-Inner items do not inherit type parameters from the functions they are embedded
-in.
+Inner items do not inherit type or const parameters from the functions
+they are embedded in.
 
 Erroneous code example:
 
diff --git a/src/librustc_resolve/error_reporting.rs b/src/librustc_resolve/error_reporting.rs
index 2a8e95536b8c7..cd771d93e00f6 100644
--- a/src/librustc_resolve/error_reporting.rs
+++ b/src/librustc_resolve/error_reporting.rs
@@ -1,14 +1,435 @@
-use {CrateLint, PathResult, Segment};
-use macros::ParentScope;
+use std::cmp::Reverse;
 
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use log::debug;
+use rustc::hir::def::*;
+use rustc::hir::def::Namespace::*;
+use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
+use rustc::session::config::nightly_options;
+use syntax::ast::{ExprKind};
 use syntax::symbol::keywords;
 use syntax_pos::Span;
 
-use resolve_imports::ImportResolver;
-use std::cmp::Reverse;
+use crate::macros::ParentScope;
+use crate::resolve_imports::ImportResolver;
+use crate::{import_candidate_to_enum_paths, is_self_type, is_self_value, path_names_to_string};
+use crate::{AssocSuggestion, CrateLint, ImportSuggestion, ModuleOrUniformRoot, PathResult,
+            PathSource, Resolver, Segment};
+
+impl<'a> Resolver<'a> {
+    /// Handles error reporting for `smart_resolve_path_fragment` function.
+    /// Creates base error and amends it with one short label and possibly some longer helps/notes.
+    pub(crate) fn smart_resolve_report_errors(
+        &mut self,
+        path: &[Segment],
+        span: Span,
+        source: PathSource<'_>,
+        def: Option<Def>,
+    ) -> (DiagnosticBuilder<'a>, Vec<ImportSuggestion>) {
+        let ident_span = path.last().map_or(span, |ident| ident.ident.span);
+        let ns = source.namespace();
+        let is_expected = &|def| source.is_expected(def);
+        let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
+
+        // Make the base error.
+        let expected = source.descr_expected();
+        let path_str = Segment::names_to_string(path);
+        let item_str = path.last().unwrap().ident;
+        let code = source.error_code(def.is_some());
+        let (base_msg, fallback_label, base_span) = if let Some(def) = def {
+            (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
+                format!("not a {}", expected),
+                span)
+        } else {
+            let item_span = path.last().unwrap().ident.span;
+            let (mod_prefix, mod_str) = if path.len() == 1 {
+                (String::new(), "this scope".to_string())
+            } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
+                (String::new(), "the crate root".to_string())
+            } else {
+                let mod_path = &path[..path.len() - 1];
+                let mod_prefix = match self.resolve_path_without_parent_scope(
+                    mod_path, Some(TypeNS), false, span, CrateLint::No
+                ) {
+                    PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
+                        module.def(),
+                    _ => None,
+                }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
+                (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
+            };
+            (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
+                format!("not found in {}", mod_str),
+                item_span)
+        };
+
+        let code = DiagnosticId::Error(code.into());
+        let mut err = self.session.struct_span_err_with_code(base_span, &base_msg, code);
+
+        // Emit help message for fake-self from other languages (e.g., `this` in Javascript).
+        if ["this", "my"].contains(&&*item_str.as_str())
+            && self.self_value_is_available(path[0].ident.span, span) {
+            err.span_suggestion(
+                span,
+                "did you mean",
+                "self".to_string(),
+                Applicability::MaybeIncorrect,
+            );
+        }
+
+        // Emit special messages for unresolved `Self` and `self`.
+        if is_self_type(path, ns) {
+            __diagnostic_used!(E0411);
+            err.code(DiagnosticId::Error("E0411".into()));
+            err.span_label(span, format!("`Self` is only available in impls, traits, \
+                                          and type definitions"));
+            return (err, Vec::new());
+        }
+        if is_self_value(path, ns) {
+            debug!("smart_resolve_path_fragment: E0424, source={:?}", source);
+
+            __diagnostic_used!(E0424);
+            err.code(DiagnosticId::Error("E0424".into()));
+            err.span_label(span, match source {
+                PathSource::Pat => {
+                    format!("`self` value is a keyword \
+                             and may not be bound to \
+                             variables or shadowed")
+                }
+                _ => {
+                    format!("`self` value is a keyword \
+                             only available in methods \
+                             with `self` parameter")
+                }
+            });
+            return (err, Vec::new());
+        }
+
+        // Try to lookup name in more relaxed fashion for better error reporting.
+        let ident = path.last().unwrap().ident;
+        let candidates = self.lookup_import_candidates(ident, ns, is_expected)
+            .drain(..)
+            .filter(|ImportSuggestion { did, .. }| {
+                match (did, def.and_then(|def| def.opt_def_id())) {
+                    (Some(suggestion_did), Some(actual_did)) => *suggestion_did != actual_did,
+                    _ => true,
+                }
+            })
+            .collect::<Vec<_>>();
+        if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
+            let enum_candidates =
+                self.lookup_import_candidates(ident, ns, is_enum_variant);
+            let mut enum_candidates = enum_candidates.iter()
+                .map(|suggestion| {
+                    import_candidate_to_enum_paths(&suggestion)
+                }).collect::<Vec<_>>();
+            enum_candidates.sort();
+
+            if !enum_candidates.is_empty() {
+                // Contextualize for E0412 "cannot find type", but don't belabor the point
+                // (that it's a variant) for E0573 "expected type, found variant".
+                let preamble = if def.is_none() {
+                    let others = match enum_candidates.len() {
+                        1 => String::new(),
+                        2 => " and 1 other".to_owned(),
+                        n => format!(" and {} others", n)
+                    };
+                    format!("there is an enum variant `{}`{}; ",
+                            enum_candidates[0].0, others)
+                } else {
+                    String::new()
+                };
+                let msg = format!("{}try using the variant's enum", preamble);
+
+                err.span_suggestions(
+                    span,
+                    &msg,
+                    enum_candidates.into_iter()
+                        .map(|(_variant_path, enum_ty_path)| enum_ty_path)
+                        // Variants re-exported in prelude doesn't mean `prelude::v1` is the
+                        // type name!
+                        // FIXME: is there a more principled way to do this that
+                        // would work for other re-exports?
+                        .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
+                        // Also write `Option` rather than `std::prelude::v1::Option`.
+                        .map(|enum_ty_path| {
+                            // FIXME #56861: DRY-er prelude filtering.
+                            enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
+                        }),
+                    Applicability::MachineApplicable,
+                );
+            }
+        }
+        if path.len() == 1 && self.self_type_is_available(span) {
+            if let Some(candidate) = self.lookup_assoc_candidate(ident, ns, is_expected) {
+                let self_is_available = self.self_value_is_available(path[0].ident.span, span);
+                match candidate {
+                    AssocSuggestion::Field => {
+                        err.span_suggestion(
+                            span,
+                            "try",
+                            format!("self.{}", path_str),
+                            Applicability::MachineApplicable,
+                        );
+                        if !self_is_available {
+                            err.span_label(span, format!("`self` value is a keyword \
+                                                         only available in \
+                                                         methods with `self` parameter"));
+                        }
+                    }
+                    AssocSuggestion::MethodWithSelf if self_is_available => {
+                        err.span_suggestion(
+                            span,
+                            "try",
+                            format!("self.{}", path_str),
+                            Applicability::MachineApplicable,
+                        );
+                    }
+                    AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
+                        err.span_suggestion(
+                            span,
+                            "try",
+                            format!("Self::{}", path_str),
+                            Applicability::MachineApplicable,
+                        );
+                    }
+                }
+                return (err, candidates);
+            }
+        }
+
+        let mut levenshtein_worked = false;
+
+        // Try Levenshtein algorithm.
+        let suggestion = self.lookup_typo_candidate(path, ns, is_expected, span);
+        if let Some(suggestion) = suggestion {
+            let msg = format!(
+                "{} {} with a similar name exists",
+                suggestion.article, suggestion.kind
+            );
+            err.span_suggestion(
+                ident_span,
+                &msg,
+                suggestion.candidate.to_string(),
+                Applicability::MaybeIncorrect,
+            );
+
+            levenshtein_worked = true;
+        }
+
+        // Try context-dependent help if relaxed lookup didn't work.
+        if let Some(def) = def {
+            if self.smart_resolve_context_dependent_help(&mut err,
+                                                         span,
+                                                         source,
+                                                         def,
+                                                         &path_str,
+                                                         &fallback_label) {
+                return (err, candidates);
+            }
+        }
+
+        // Fallback label.
+        if !levenshtein_worked {
+            err.span_label(base_span, fallback_label);
+            self.type_ascription_suggestion(&mut err, base_span);
+        }
+        (err, candidates)
+    }
+
+    /// Provides context-dependent help for errors reported by the `smart_resolve_path_fragment`
+    /// function.
+    /// Returns `true` if able to provide context-dependent help.
+    fn smart_resolve_context_dependent_help(
+        &mut self,
+        err: &mut DiagnosticBuilder<'a>,
+        span: Span,
+        source: PathSource<'_>,
+        def: Def,
+        path_str: &str,
+        fallback_label: &str,
+    ) -> bool {
+        let ns = source.namespace();
+        let is_expected = &|def| source.is_expected(def);
+
+        match (def, source) {
+            (Def::Macro(..), _) => {
+                err.span_suggestion(
+                    span,
+                    "use `!` to invoke the macro",
+                    format!("{}!", path_str),
+                    Applicability::MaybeIncorrect,
+                );
+                if path_str == "try" && span.rust_2015() {
+                    err.note("if you want the `try` keyword, \
+                        you need to be in the 2018 edition");
+                }
+            }
+            (Def::TyAlias(..), PathSource::Trait(_)) => {
+                err.span_label(span, "type aliases cannot be used as traits");
+                if nightly_options::is_nightly_build() {
+                    err.note("did you mean to use a trait alias?");
+                }
+            }
+            (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
+                ExprKind::Field(_, ident) => {
+                    err.span_suggestion(
+                        parent.span,
+                        "use the path separator to refer to an item",
+                        format!("{}::{}", path_str, ident),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
+                ExprKind::MethodCall(ref segment, ..) => {
+                    let span = parent.span.with_hi(segment.ident.span.hi());
+                    err.span_suggestion(
+                        span,
+                        "use the path separator to refer to an item",
+                        format!("{}::{}", path_str, segment.ident),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
+                _ => return false,
+            },
+            (Def::Enum(..), PathSource::TupleStruct)
+                | (Def::Enum(..), PathSource::Expr(..))  => {
+                if let Some(variants) = self.collect_enum_variants(def) {
+                    err.note(&format!("did you mean to use one \
+                                       of the following variants?\n{}",
+                        variants.iter()
+                            .map(|suggestion| path_names_to_string(suggestion))
+                            .map(|suggestion| format!("- `{}`", suggestion))
+                            .collect::<Vec<_>>()
+                            .join("\n")));
+                } else {
+                    err.note("did you mean to use one of the enum's variants?");
+                }
+            },
+            (Def::Struct(def_id), _) if ns == ValueNS => {
+                if let Some((ctor_def, ctor_vis))
+                        = self.struct_constructors.get(&def_id).cloned() {
+                    let accessible_ctor = self.is_accessible(ctor_vis);
+                    if is_expected(ctor_def) && !accessible_ctor {
+                        err.span_label(span, format!("constructor is not visible \
+                                                      here due to private fields"));
+                    }
+                } else {
+                    // HACK(estebank): find a better way to figure out that this was a
+                    // parser issue where a struct literal is being used on an expression
+                    // where a brace being opened means a block is being started. Look
+                    // ahead for the next text to see if `span` is followed by a `{`.
+                    let sm = self.session.source_map();
+                    let mut sp = span;
+                    loop {
+                        sp = sm.next_point(sp);
+                        match sm.span_to_snippet(sp) {
+                            Ok(ref snippet) => {
+                                if snippet.chars().any(|c| { !c.is_whitespace() }) {
+                                    break;
+                                }
+                            }
+                            _ => break,
+                        }
+                    }
+                    let followed_by_brace = match sm.span_to_snippet(sp) {
+                        Ok(ref snippet) if snippet == "{" => true,
+                        _ => false,
+                    };
+                    // In case this could be a struct literal that needs to be surrounded
+                    // by parenthesis, find the appropriate span.
+                    let mut i = 0;
+                    let mut closing_brace = None;
+                    loop {
+                        sp = sm.next_point(sp);
+                        match sm.span_to_snippet(sp) {
+                            Ok(ref snippet) => {
+                                if snippet == "}" {
+                                    let sp = span.to(sp);
+                                    if let Ok(snippet) = sm.span_to_snippet(sp) {
+                                        closing_brace = Some((sp, snippet));
+                                    }
+                                    break;
+                                }
+                            }
+                            _ => break,
+                        }
+                        i += 1;
+                        // The bigger the span, the more likely we're incorrect --
+                        // bound it to 100 chars long.
+                        if i > 100 {
+                            break;
+                        }
+                    }
+                    match source {
+                        PathSource::Expr(Some(parent)) => {
+                            match parent.node {
+                                ExprKind::MethodCall(ref path_assignment, _)  => {
+                                    err.span_suggestion(
+                                        sm.start_point(parent.span)
+                                            .to(path_assignment.ident.span),
+                                        "use `::` to access an associated function",
+                                        format!("{}::{}",
+                                                path_str,
+                                                path_assignment.ident),
+                                        Applicability::MaybeIncorrect
+                                    );
+                                },
+                                _ => {
+                                    err.span_label(
+                                        span,
+                                        format!("did you mean `{} {{ /* fields */ }}`?",
+                                                path_str),
+                                    );
+                                },
+                            }
+                        },
+                        PathSource::Expr(None) if followed_by_brace == true => {
+                            if let Some((sp, snippet)) = closing_brace {
+                                err.span_suggestion(
+                                    sp,
+                                    "surround the struct literal with parenthesis",
+                                    format!("({})", snippet),
+                                    Applicability::MaybeIncorrect,
+                                );
+                            } else {
+                                err.span_label(
+                                    span,
+                                    format!("did you mean `({} {{ /* fields */ }})`?",
+                                            path_str),
+                                );
+                            }
+                        },
+                        _ => {
+                            err.span_label(
+                                span,
+                                format!("did you mean `{} {{ /* fields */ }}`?",
+                                        path_str),
+                            );
+                        },
+                    }
+                }
+            }
+            (Def::Union(..), _) |
+            (Def::Variant(..), _) |
+            (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
+                err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
+                                             path_str));
+            }
+            (Def::SelfTy(..), _) if ns == ValueNS => {
+                err.span_label(span, fallback_label);
+                err.note("can't use `Self` as a constructor, you must use the \
+                          implemented struct");
+            }
+            (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
+                err.note("can't use a type alias as a constructor");
+            }
+            _ => return false,
+        }
+        true
+    }
+}
 
 impl<'a, 'b:'a> ImportResolver<'a, 'b> {
-    /// Add suggestions for a path that cannot be resolved.
+    /// Adds suggestions for a path that cannot be resolved.
     pub(crate) fn make_path_suggestion(
         &mut self,
         span: Span,
@@ -22,7 +443,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
             // On 2015 `{{root}}` is usually added implicitly.
             (Some(fst), Some(snd)) if fst.ident.name == keywords::PathRoot.name() &&
                                       !snd.ident.is_path_segment_keyword() => {}
-            // `ident::...` on 2018
+            // `ident::...` on 2018.
             (Some(fst), _) if fst.ident.span.rust_2018() &&
                               !fst.ident.is_path_segment_keyword() => {
                 // Insert a placeholder that's later replaced by `self`/`super`/etc.
@@ -61,7 +482,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         }
     }
 
-    /// Suggest a missing `crate::` if that resolves to an correct module.
+    /// Suggests a missing `crate::` if that resolves to an correct module.
     ///
     /// ```
     ///    |
@@ -92,7 +513,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         }
     }
 
-    /// Suggest a missing `super::` if that resolves to an correct module.
+    /// Suggests a missing `super::` if that resolves to an correct module.
     ///
     /// ```
     ///    |
@@ -116,7 +537,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         }
     }
 
-    /// Suggest a missing external crate name if that resolves to an correct module.
+    /// Suggests a missing external crate name if that resolves to an correct module.
     ///
     /// ```
     ///    |
@@ -137,7 +558,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         }
 
         // Sort extern crate names in reverse order to get
-        // 1) some consistent ordering for emitted dignostics and
+        // 1) some consistent ordering for emitted dignostics, and
         // 2) `std` suggestions before `core` suggestions.
         let mut extern_crate_names =
             self.resolver.extern_prelude.iter().map(|(ident, _)| ident.name).collect::<Vec<_>>();
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index b41193723069c..1a7744786d80e 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -1,33 +1,18 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(crate_visibility_modifier)]
 #![feature(label_break_value)]
 #![feature(nll)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(slice_sort_by_cached_key)]
 
 #![recursion_limit="256"]
 
-#[macro_use]
-extern crate bitflags;
-#[macro_use]
-extern crate log;
-#[macro_use]
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc_errors as errors;
-extern crate arena;
-#[macro_use]
-extern crate rustc;
-extern crate rustc_data_structures;
-extern crate rustc_metadata;
+#![deny(rust_2018_idioms)]
 
 pub use rustc::hir::def::{Namespace, PerNS};
 
-use self::TypeParameters::*;
-use self::RibKind::*;
+use GenericParameters::*;
+use RibKind::*;
 
 use rustc::hir::map::{Definitions, DefCollector};
 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
@@ -38,9 +23,9 @@ use rustc::hir::def::*;
 use rustc::hir::def::Namespace::*;
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
-use rustc::session::config::nightly_options;
-use rustc::ty;
+use rustc::ty::{self, DefIdTree};
 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
+use rustc::{bug, span_bug};
 
 use rustc_metadata::creader::CrateLoader;
 use rustc_metadata::cstore::CStore;
@@ -62,10 +47,13 @@ use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
 use syntax::ptr::P;
+use syntax::{span_err, struct_span_err, unwrap_or, walk_list};
 
-use syntax_pos::{Span, DUMMY_SP, MultiSpan};
+use syntax_pos::{BytePos, Span, DUMMY_SP, MultiSpan};
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
 
+use log::debug;
+
 use std::cell::{Cell, RefCell};
 use std::{cmp, fmt, iter, mem, ptr};
 use std::collections::BTreeSet;
@@ -103,6 +91,7 @@ enum ScopeSet {
 
 /// A free importable items suggested in case of resolution failure.
 struct ImportSuggestion {
+    did: Option<DefId>,
     path: Path,
 }
 
@@ -149,65 +138,67 @@ impl Ord for BindingError {
 }
 
 enum ResolutionError<'a> {
-    /// error E0401: can't use type parameters from outer function
-    TypeParametersFromOuterFunction(Def),
-    /// error E0403: the name is already used for a type parameter in this type parameter list
-    NameAlreadyUsedInTypeParameterList(Name, &'a Span),
-    /// error E0407: method is not a member of trait
+    /// Error E0401: can't use type or const parameters from outer function.
+    GenericParamsFromOuterFunction(Def),
+    /// Error E0403: the name is already used for a type or const parameter in this generic
+    /// parameter list.
+    NameAlreadyUsedInParameterList(Name, &'a Span),
+    /// Error E0407: method is not a member of trait.
     MethodNotMemberOfTrait(Name, &'a str),
-    /// error E0437: type is not a member of trait
+    /// Error E0437: type is not a member of trait.
     TypeNotMemberOfTrait(Name, &'a str),
-    /// error E0438: const is not a member of trait
+    /// Error E0438: const is not a member of trait.
     ConstNotMemberOfTrait(Name, &'a str),
-    /// error E0408: variable `{}` is not bound in all patterns
+    /// Error E0408: variable `{}` is not bound in all patterns.
     VariableNotBoundInPattern(&'a BindingError),
-    /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
+    /// Error E0409: variable `{}` is bound in inconsistent ways within the same match arm.
     VariableBoundWithDifferentMode(Name, Span),
-    /// error E0415: identifier is bound more than once in this parameter list
+    /// Error E0415: identifier is bound more than once in this parameter list.
     IdentifierBoundMoreThanOnceInParameterList(&'a str),
-    /// error E0416: identifier is bound more than once in the same pattern
+    /// Error E0416: identifier is bound more than once in the same pattern.
     IdentifierBoundMoreThanOnceInSamePattern(&'a str),
-    /// error E0426: use of undeclared label
+    /// Error E0426: use of undeclared label.
     UndeclaredLabel(&'a str, Option<Name>),
-    /// error E0429: `self` imports are only allowed within a { } list
+    /// Error E0429: `self` imports are only allowed within a `{ }` list.
     SelfImportsOnlyAllowedWithin,
-    /// error E0430: `self` import can only appear once in the list
+    /// Error E0430: `self` import can only appear once in the list.
     SelfImportCanOnlyAppearOnceInTheList,
-    /// error E0431: `self` import can only appear in an import list with a non-empty prefix
+    /// Error E0431: `self` import can only appear in an import list with a non-empty prefix.
     SelfImportOnlyInImportListWithNonEmptyPrefix,
-    /// error E0433: failed to resolve
+    /// Error E0433: failed to resolve.
     FailedToResolve(&'a str),
-    /// error E0434: can't capture dynamic environment in a fn item
+    /// Error E0434: can't capture dynamic environment in a fn item.
     CannotCaptureDynamicEnvironmentInFnItem,
-    /// error E0435: attempt to use a non-constant value in a constant
+    /// Error E0435: attempt to use a non-constant value in a constant.
     AttemptToUseNonConstantValueInConstant,
-    /// error E0530: X bindings cannot shadow Ys
+    /// Error E0530: `X` bindings cannot shadow `Y`s.
     BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
-    /// error E0128: type parameters with a default cannot use forward declared identifiers
-    ForwardDeclaredTyParam,
+    /// Error E0128: type parameters with a default cannot use forward-declared identifiers.
+    ForwardDeclaredTyParam, // FIXME(const_generics:defaults)
 }
 
-/// Combines an error with provided span and emits it
+/// Combines an error with provided span and emits it.
 ///
 /// This takes the error provided, combines it with the span and any additional spans inside the
 /// error and emits it.
-fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
+fn resolve_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
                             span: Span,
                             resolution_error: ResolutionError<'a>) {
     resolve_struct_error(resolver, span, resolution_error).emit();
 }
 
-fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
+fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver<'_>,
                                    span: Span,
                                    resolution_error: ResolutionError<'a>)
                                    -> DiagnosticBuilder<'sess> {
     match resolution_error {
-        ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
+        ResolutionError::GenericParamsFromOuterFunction(outer_def) => {
             let mut err = struct_span_err!(resolver.session,
-                                           span,
-                                           E0401,
-                                           "can't use type parameters from outer function");
-            err.span_label(span, "use of type variable from outer function");
+                span,
+                E0401,
+                "can't use generic parameters from outer function",
+            );
+            err.span_label(span, format!("use of generic parameter from outer function"));
 
             let cm = resolver.session.source_map();
             match outer_def {
@@ -231,42 +222,48 @@ fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
                     }
                     return err;
                 },
-                Def::TyParam(typaram_defid) => {
-                    if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
-                        err.span_label(typaram_span, "type variable from outer function");
+                Def::TyParam(def_id) => {
+                    if let Some(span) = resolver.definitions.opt_span(def_id) {
+                        err.span_label(span, "type variable from outer function");
                     }
-                },
+                }
+                Def::ConstParam(def_id) => {
+                    if let Some(span) = resolver.definitions.opt_span(def_id) {
+                        err.span_label(span, "const variable from outer function");
+                    }
+                }
                 _ => {
-                    bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
-                         Def::TyParam")
+                    bug!("GenericParamsFromOuterFunction should only be used with Def::SelfTy, \
+                         Def::TyParam");
                 }
             }
 
             // Try to retrieve the span of the function signature and generate a new message with
-            // a local type parameter
-            let sugg_msg = "try using a local type parameter instead";
+            // a local type or const parameter.
+            let sugg_msg = &format!("try using a local generic parameter instead");
             if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
                 // Suggest the modification to the user
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     sugg_span,
                     sugg_msg,
                     new_snippet,
                     Applicability::MachineApplicable,
                 );
             } else if let Some(sp) = cm.generate_fn_name_span(span) {
-                err.span_label(sp, "try adding a local type parameter in this method instead");
+                err.span_label(sp,
+                    format!("try adding a local generic parameter in this method instead"));
             } else {
-                err.help("try using a local type parameter instead");
+                err.help(&format!("try using a local generic parameter instead"));
             }
 
             err
         }
-        ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
+        ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => {
              let mut err = struct_span_err!(resolver.session,
                                             span,
                                             E0403,
-                                            "the name `{}` is already used for a type parameter \
-                                            in this type parameter list",
+                                            "the name `{}` is already used for a generic \
+                                            parameter in this list of generic parameters",
                                             name);
              err.span_label(span, "already used");
              err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
@@ -428,11 +425,11 @@ fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
 
 /// Adjust the impl span so that just the `impl` keyword is taken by removing
 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
-/// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
+/// everything after the first whitespace (`"impl Iterator for A" -> "impl"`).
 ///
-/// Attention: The method used is very fragile since it essentially duplicates the work of the
+/// *Attention*: the method used is very fragile since it essentially duplicates the work of the
 /// parser. If you need to use this function or something similar, please consider updating the
-/// source_map functions and this function to something more robust.
+/// `source_map` functions and this function to something more robust.
 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
     let impl_span = cm.span_until_char(impl_span, '<');
     let impl_span = cm.span_until_whitespace(impl_span);
@@ -553,8 +550,7 @@ impl<'a> PathSource<'a> {
                 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
                 Def::Trait(..) | Def::TraitAlias(..) | Def::TyAlias(..) |
                 Def::AssociatedTy(..) | Def::PrimTy(..) | Def::TyParam(..) |
-                Def::SelfTy(..) | Def::Existential(..) |
-                Def::ForeignTy(..) => true,
+                Def::SelfTy(..) | Def::Existential(..) | Def::ForeignTy(..) => true,
                 _ => false,
             },
             PathSource::Trait(AliasPossibility::No) => match def {
@@ -571,7 +567,7 @@ impl<'a> PathSource<'a> {
                 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
                 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
                 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
-                Def::SelfCtor(..) => true,
+                Def::SelfCtor(..) | Def::ConstParam(..) => true,
                 _ => false,
             },
             PathSource::Pat => match def {
@@ -743,7 +739,7 @@ impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
     }
 }
 
-/// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
+/// Walks the whole crate in DFS order, visiting each item, resolving names as it goes.
 impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
     fn visit_item(&mut self, item: &'tcx Item) {
         self.resolve_item(item);
@@ -755,6 +751,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
         self.resolve_block(block);
     }
     fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
+        debug!("visit_anon_const {:?}", constant);
         self.with_constant_rib(|this| {
             visit::walk_anon_const(this, constant);
         });
@@ -788,15 +785,15 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
         visit::walk_poly_trait_ref(self, tref, m);
     }
     fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
-        let type_parameters = match foreign_item.node {
+        let generic_params = match foreign_item.node {
             ForeignItemKind::Fn(_, ref generics) => {
-                HasTypeParameters(generics, ItemRibKind)
+                HasGenericParams(generics, ItemRibKind)
             }
-            ForeignItemKind::Static(..) => NoTypeParameters,
-            ForeignItemKind::Ty => NoTypeParameters,
-            ForeignItemKind::Macro(..) => NoTypeParameters,
+            ForeignItemKind::Static(..) => NoGenericParams,
+            ForeignItemKind::Ty => NoGenericParams,
+            ForeignItemKind::Macro(..) => NoGenericParams,
         };
-        self.with_type_parameter_rib(type_parameters, |this| {
+        self.with_generic_param_rib(generic_params, |this| {
             visit::walk_foreign_item(this, foreign_item);
         });
     }
@@ -806,6 +803,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
                 _: Span,
                 node_id: NodeId)
     {
+        debug!("(resolving function) entering function");
         let (rib_kind, asyncness) = match function_kind {
             FnKind::ItemFn(_, ref header, ..) =>
                 (ItemRibKind, header.asyncness),
@@ -862,6 +860,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
         self.label_ribs.pop();
         self.ribs[ValueNS].pop();
     }
+
     fn visit_generics(&mut self, generics: &'tcx Generics) {
         // For type parameter defaults, we have to ban access
         // to following type parameters, as the Substs can only
@@ -872,6 +871,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
         let mut found_default = false;
         default_ban_rib.bindings.extend(generics.params.iter()
             .filter_map(|param| match param.kind {
+                GenericParamKind::Const { .. } |
                 GenericParamKind::Lifetime { .. } => None,
                 GenericParamKind::Type { ref default, .. } => {
                     found_default |= default.is_some();
@@ -900,6 +900,13 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
                     // Allow all following defaults to refer to this type parameter.
                     default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
                 }
+                GenericParamKind::Const { ref ty } => {
+                    for bound in &param.bounds {
+                        self.visit_param_bound(bound);
+                    }
+
+                    self.visit_ty(ty);
+                }
             }
         }
         for p in &generics.where_clause.predicates {
@@ -909,9 +916,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Resolver<'a> {
 }
 
 #[derive(Copy, Clone)]
-enum TypeParameters<'a, 'b> {
-    NoTypeParameters,
-    HasTypeParameters(// Type parameters.
+enum GenericParameters<'a, 'b> {
+    NoGenericParams,
+    HasGenericParams(// Type parameters.
                       &'b Generics,
 
                       // The kind of the rib used for type parameters.
@@ -925,7 +932,7 @@ enum RibKind<'a> {
     /// No translation needs to be applied.
     NormalRibKind,
 
-    /// We passed through a closure scope at the given node ID.
+    /// We passed through a closure scope at the given `NodeId`.
     /// Translate upvars as appropriate.
     ClosureRibKind(NodeId /* func id */),
 
@@ -953,7 +960,7 @@ enum RibKind<'a> {
     ForwardTyParamBanRibKind,
 }
 
-/// One local scope.
+/// A single local scope.
 ///
 /// A rib represents a scope names can live in. Note that these appear in many places, not just
 /// around braces. At any place where the list of accessible names (of the given namespace)
@@ -1047,7 +1054,7 @@ enum PathResult<'a> {
 }
 
 enum ModuleKind {
-    /// An anonymous module, eg. just a block.
+    /// An anonymous module; e.g., just a block.
     ///
     /// ```
     /// fn main() {
@@ -1192,7 +1199,7 @@ impl<'a> ModuleData<'a> {
 }
 
 impl<'a> fmt::Debug for ModuleData<'a> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{:?}", self.def())
     }
 }
@@ -1228,15 +1235,25 @@ enum NameBindingKind<'a> {
     },
 }
 
+impl<'a> NameBindingKind<'a> {
+    /// Is this a name binding of a import?
+    fn is_import(&self) -> bool {
+        match *self {
+            NameBindingKind::Import { .. } => true,
+            _ => false,
+        }
+    }
+}
+
 struct PrivacyError<'a>(Span, Ident, &'a NameBinding<'a>);
 
 struct UseError<'a> {
     err: DiagnosticBuilder<'a>,
-    /// Attach `use` statements for these candidates
+    /// Attach `use` statements for these candidates.
     candidates: Vec<ImportSuggestion>,
-    /// The node id of the module to place the use statements in
+    /// The `NodeId` of the module to place the use-statements in.
     node_id: NodeId,
-    /// Whether the diagnostic should state that it's "better"
+    /// Whether the diagnostic should state that it's "better".
     better: bool,
 }
 
@@ -1406,7 +1423,7 @@ impl<'a> NameBinding<'a> {
     // in some later round and screw up our previously found resolution.
     // See more detailed explanation in
     // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
-    fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
+    fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding<'_>) -> bool {
         // self > max(invoc, binding) => !(self <= invoc || self <= binding)
         // Expansions are partially ordered, so "may appear after" is an inversion of
         // "certainly appears before or simultaneously" and includes unordered cases.
@@ -1478,7 +1495,7 @@ pub struct Resolver<'a> {
     prelude: Option<Module<'a>>,
     pub extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'a>>,
 
-    /// n.b. This is used only for better diagnostics, not name resolution itself.
+    /// N.B., this is used only for better diagnostics, not name resolution itself.
     has_self: FxHashSet<DefId>,
 
     /// Names of fields of an item `DefId` accessible with dot syntax.
@@ -1557,13 +1574,13 @@ pub struct Resolver<'a> {
     /// they are used (in a `break` or `continue` statement)
     pub unused_labels: FxHashMap<NodeId, Span>,
 
-    /// privacy errors are delayed until the end in order to deduplicate them
+    /// Privacy errors are delayed until the end in order to deduplicate them.
     privacy_errors: Vec<PrivacyError<'a>>,
-    /// ambiguity errors are delayed for deduplication
+    /// Ambiguity errors are delayed for deduplication.
     ambiguity_errors: Vec<AmbiguityError<'a>>,
-    /// `use` injections are delayed for better placement and deduplication
+    /// `use` injections are delayed for better placement and deduplication.
     use_injections: Vec<UseError<'a>>,
-    /// crate-local macro expanded `macro_export` referred to by a module-relative path
+    /// Crate-local macro expanded `macro_export` referred to by a module-relative path.
     macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
 
     arenas: &'a ResolverArenas<'a>,
@@ -1590,17 +1607,17 @@ pub struct Resolver<'a> {
 
     potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
 
-    /// This table maps struct IDs into struct constructor IDs,
+    /// Table for mapping struct IDs into struct constructor IDs,
     /// it's not used during normal resolution, only for better error reporting.
     struct_constructors: DefIdMap<(Def, ty::Visibility)>,
 
-    /// Only used for better errors on `fn(): fn()`
+    /// Only used for better errors on `fn(): fn()`.
     current_type_ascription: Vec<Span>,
 
     injected_crate: Option<Module<'a>>,
 }
 
-/// Nothing really interesting here, it just provides memory for the rest of the crate.
+/// Nothing really interesting here; it just provides memory for the rest of the crate.
 #[derive(Default)]
 pub struct ResolverArenas<'a> {
     modules: arena::TypedArena<ModuleData<'a>>,
@@ -1620,14 +1637,14 @@ impl<'a> ResolverArenas<'a> {
         }
         module
     }
-    fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
+    fn local_modules(&'a self) -> std::cell::Ref<'a, Vec<Module<'a>>> {
         self.local_modules.borrow()
     }
     fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
         self.name_bindings.alloc(name_binding)
     }
     fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
-                              -> &'a ImportDirective {
+                              -> &'a ImportDirective<'_> {
         self.import_directives.alloc(import_directive)
     }
     fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
@@ -1700,7 +1717,7 @@ impl<'a> hir::lowering::Resolver for Resolver<'a> {
 }
 
 impl<'a> Resolver<'a> {
-    /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
+    /// Rustdoc uses this to resolve things in a recoverable way. `ResolutionError<'a>`
     /// isn't something that can be returned because it can't be made to live that long,
     /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
     /// just that an error occurred.
@@ -1737,20 +1754,20 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    /// resolve_hir_path, but takes a callback in case there was an error
+    /// Like `resolve_hir_path`, but takes a callback in case there was an error.
     fn resolve_hir_path_cb<F>(
         &mut self,
         path: &ast::Path,
         is_value: bool,
         error_callback: F,
     ) -> hir::Path
-        where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
+        where F: for<'c, 'b> FnOnce(&'c mut Resolver<'_>, Span, ResolutionError<'b>)
     {
         let namespace = if is_value { ValueNS } else { TypeNS };
         let span = path.span;
         let segments = &path.segments;
         let path = Segment::from_path(&path);
-        // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
+        // FIXME(Manishearth): intra-doc links won't get warned of epoch changes.
         let def = match self.resolve_path_without_parent_scope(&path, Some(namespace), true,
                                                                span, CrateLint::No) {
             PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
@@ -1809,7 +1826,7 @@ impl<'a> Resolver<'a> {
         DefCollector::new(&mut definitions, Mark::root())
             .collect_root(crate_name, session.local_crate_disambiguator());
 
-        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry> =
+        let mut extern_prelude: FxHashMap<Ident, ExternPreludeEntry<'_>> =
             session.opts.externs.iter().map(|kv| (Ident::from_str(kv.0), Default::default()))
                                        .collect();
 
@@ -2037,6 +2054,7 @@ impl<'a> Resolver<'a> {
         let record_used = record_used_id.is_some();
         let mut module = self.graph_root;
         for i in (0 .. self.ribs[ns].len()).rev() {
+            debug!("walk rib\n{:?}", self.ribs[ns][i].bindings);
             if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
                 // The ident resolves to a type parameter or local variable.
                 return Some(LexicalScopeBinding::Def(
@@ -2305,7 +2323,7 @@ impl<'a> Resolver<'a> {
     // implementations thus found, for compatibility with old resolve pass.
 
     pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
-        where F: FnOnce(&mut Resolver) -> T
+        where F: FnOnce(&mut Resolver<'_>) -> T
     {
         let id = self.definitions.local_def_id(id);
         let module = self.module_map.get(&id).cloned(); // clones a reference
@@ -2327,12 +2345,12 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    /// Searches the current set of local scopes for labels. Returns the first non-None label that
+    /// Searches the current set of local scopes for labels. Returns the first non-`None` label that
     /// is returned by the given predicate function
     ///
     /// Stops after meeting a closure.
     fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
-        where P: Fn(&Rib, Ident) -> Option<R>
+        where P: Fn(&Rib<'_>, Ident) -> Option<R>
     {
         for rib in self.label_ribs.iter().rev() {
             match rib.kind {
@@ -2358,8 +2376,9 @@ impl<'a> Resolver<'a> {
     }
 
     fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
+        debug!("resolve_adt");
         self.with_current_self_item(item, |this| {
-            this.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
+            this.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
                 let item_def_id = this.definitions.local_def_id(item.id);
                 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
                     visit::walk_item(this, item);
@@ -2412,13 +2431,13 @@ impl<'a> Resolver<'a> {
 
     fn resolve_item(&mut self, item: &Item) {
         let name = item.ident.name;
-        debug!("(resolving item) resolving {}", name);
+        debug!("(resolving item) resolving {} ({:?})", name, item.node);
 
         match item.node {
             ItemKind::Ty(_, ref generics) |
             ItemKind::Fn(_, _, ref generics, _) |
             ItemKind::Existential(_, ref generics) => {
-                self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
+                self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind),
                                              |this| visit::walk_item(this, item));
             }
 
@@ -2437,16 +2456,16 @@ impl<'a> Resolver<'a> {
 
             ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
                 // Create a new rib for the trait-wide type parameters.
-                self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
+                self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
                     let local_def_id = this.definitions.local_def_id(item.id);
                     this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
                         this.visit_generics(generics);
                         walk_list!(this, visit_param_bound, bounds);
 
                         for trait_item in trait_items {
-                            let type_parameters = HasTypeParameters(&trait_item.generics,
+                            let generic_params = HasGenericParams(&trait_item.generics,
                                                                     TraitOrImplItemRibKind);
-                            this.with_type_parameter_rib(type_parameters, |this| {
+                            this.with_generic_param_rib(generic_params, |this| {
                                 match trait_item.node {
                                     TraitItemKind::Const(ref ty, ref default) => {
                                         this.visit_ty(ty);
@@ -2478,7 +2497,7 @@ impl<'a> Resolver<'a> {
 
             ItemKind::TraitAlias(ref generics, ref bounds) => {
                 // Create a new rib for the trait-wide type parameters.
-                self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
+                self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
                     let local_def_id = this.definitions.local_def_id(item.id);
                     this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
                         this.visit_generics(generics);
@@ -2495,6 +2514,7 @@ impl<'a> Resolver<'a> {
 
             ItemKind::Static(ref ty, _, ref expr) |
             ItemKind::Const(ref ty, ref expr) => {
+                debug!("resolve_item ItemKind::Const");
                 self.with_item_rib(|this| {
                     this.visit_ty(ty);
                     this.with_constant_rib(|this| {
@@ -2516,23 +2536,25 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
-        where F: FnOnce(&mut Resolver)
+    fn with_generic_param_rib<'b, F>(&'b mut self, generic_params: GenericParameters<'a, 'b>, f: F)
+        where F: FnOnce(&mut Resolver<'_>)
     {
-        match type_parameters {
-            HasTypeParameters(generics, rib_kind) => {
+        debug!("with_generic_param_rib");
+        match generic_params {
+            HasGenericParams(generics, rib_kind) => {
                 let mut function_type_rib = Rib::new(rib_kind);
+                let mut function_value_rib = Rib::new(rib_kind);
                 let mut seen_bindings = FxHashMap::default();
                 for param in &generics.params {
                     match param.kind {
                         GenericParamKind::Lifetime { .. } => {}
                         GenericParamKind::Type { .. } => {
                             let ident = param.ident.modern();
-                            debug!("with_type_parameter_rib: {}", param.id);
+                            debug!("with_generic_param_rib: {}", param.id);
 
                             if seen_bindings.contains_key(&ident) {
                                 let span = seen_bindings.get(&ident).unwrap();
-                                let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
+                                let err = ResolutionError::NameAlreadyUsedInParameterList(
                                     ident.name,
                                     span,
                                 );
@@ -2545,25 +2567,45 @@ impl<'a> Resolver<'a> {
                             function_type_rib.bindings.insert(ident, def);
                             self.record_def(param.id, PathResolution::new(def));
                         }
+                        GenericParamKind::Const { .. } => {
+                            let ident = param.ident.modern();
+                            debug!("with_generic_param_rib: {}", param.id);
+
+                            if seen_bindings.contains_key(&ident) {
+                                let span = seen_bindings.get(&ident).unwrap();
+                                let err = ResolutionError::NameAlreadyUsedInParameterList(
+                                    ident.name,
+                                    span,
+                                );
+                                resolve_error(self, param.ident.span, err);
+                            }
+                            seen_bindings.entry(ident).or_insert(param.ident.span);
+
+                            let def = Def::ConstParam(self.definitions.local_def_id(param.id));
+                            function_value_rib.bindings.insert(ident, def);
+                            self.record_def(param.id, PathResolution::new(def));
+                        }
                     }
                 }
+                self.ribs[ValueNS].push(function_value_rib);
                 self.ribs[TypeNS].push(function_type_rib);
             }
 
-            NoTypeParameters => {
+            NoGenericParams => {
                 // Nothing to do.
             }
         }
 
         f(self);
 
-        if let HasTypeParameters(..) = type_parameters {
+        if let HasGenericParams(..) = generic_params {
             self.ribs[TypeNS].pop();
+            self.ribs[ValueNS].pop();
         }
     }
 
     fn with_label_rib<F>(&mut self, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
         self.label_ribs.push(Rib::new(NormalRibKind));
         f(self);
@@ -2571,7 +2613,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_item_rib<F>(&mut self, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
         self.ribs[ValueNS].push(Rib::new(ItemRibKind));
         self.ribs[TypeNS].push(Rib::new(ItemRibKind));
@@ -2581,8 +2623,9 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_constant_rib<F>(&mut self, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
+        debug!("with_constant_rib");
         self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
         self.label_ribs.push(Rib::new(ConstantItemRibKind));
         f(self);
@@ -2591,7 +2634,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
-        where F: FnOnce(&mut Resolver) -> T
+        where F: FnOnce(&mut Resolver<'_>) -> T
     {
         // Handle nested impls (inside fn bodies)
         let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
@@ -2601,7 +2644,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_current_self_item<T, F>(&mut self, self_item: &Item, f: F) -> T
-        where F: FnOnce(&mut Resolver) -> T
+        where F: FnOnce(&mut Resolver<'_>) -> T
     {
         let previous_value = replace(&mut self.current_self_item, Some(self_item.id));
         let result = f(self);
@@ -2609,9 +2652,9 @@ impl<'a> Resolver<'a> {
         result
     }
 
-    /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`)
+    /// This is called to resolve a trait reference from an `impl` (i.e., `impl Trait for Foo`).
     fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
-        where F: FnOnce(&mut Resolver, Option<DefId>) -> T
+        where F: FnOnce(&mut Resolver<'_>, Option<DefId>) -> T
     {
         let mut new_val = None;
         let mut new_id = None;
@@ -2648,7 +2691,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_self_rib<F>(&mut self, self_def: Def, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
         let mut self_type_rib = Rib::new(NormalRibKind);
 
@@ -2660,7 +2703,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
         let self_def = Def::SelfCtor(impl_id);
         let mut self_type_rib = Rib::new(NormalRibKind);
@@ -2676,8 +2719,9 @@ impl<'a> Resolver<'a> {
                               self_type: &Ty,
                               item_id: NodeId,
                               impl_items: &[ImplItem]) {
+        debug!("resolve_implementation");
         // If applicable, create a rib for the type parameters.
-        self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
+        self.with_generic_param_rib(HasGenericParams(generics, ItemRibKind), |this| {
             // Dummy self type for better errors if `Self` is used in the trait path.
             this.with_self_rib(Def::SelfTy(None, None), |this| {
                 // Resolve the trait reference, if necessary.
@@ -2690,30 +2734,37 @@ impl<'a> Resolver<'a> {
                         }
                         // Resolve the self type.
                         this.visit_ty(self_type);
-                        // Resolve the type parameters.
+                        // Resolve the generic parameters.
                         this.visit_generics(generics);
                         // Resolve the items within the impl.
                         this.with_current_self_type(self_type, |this| {
                             this.with_self_struct_ctor_rib(item_def_id, |this| {
+                                debug!("resolve_implementation with_self_struct_ctor_rib");
                                 for impl_item in impl_items {
                                     this.resolve_visibility(&impl_item.vis);
 
                                     // We also need a new scope for the impl item type parameters.
-                                    let type_parameters = HasTypeParameters(&impl_item.generics,
-                                                                            TraitOrImplItemRibKind);
-                                    this.with_type_parameter_rib(type_parameters, |this| {
+                                    let generic_params = HasGenericParams(&impl_item.generics,
+                                                                          TraitOrImplItemRibKind);
+                                    this.with_generic_param_rib(generic_params, |this| {
                                         use self::ResolutionError::*;
                                         match impl_item.node {
                                             ImplItemKind::Const(..) => {
+                                                debug!(
+                                                    "resolve_implementation ImplItemKind::Const",
+                                                );
                                                 // If this is a trait impl, ensure the const
                                                 // exists in trait
-                                                this.check_trait_item(impl_item.ident,
-                                                                      ValueNS,
-                                                                      impl_item.span,
-                                                    |n, s| ConstNotMemberOfTrait(n, s));
-                                                this.with_constant_rib(|this|
-                                                    visit::walk_impl_item(this, impl_item)
+                                                this.check_trait_item(
+                                                    impl_item.ident,
+                                                    ValueNS,
+                                                    impl_item.span,
+                                                    |n, s| ConstNotMemberOfTrait(n, s),
                                                 );
+
+                                                this.with_constant_rib(|this| {
+                                                    visit::walk_impl_item(this, impl_item)
+                                                });
                                             }
                                             ImplItemKind::Method(..) => {
                                                 // If this is a trait impl, ensure the method
@@ -2761,7 +2812,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
-        where F: FnOnce(Name, &str) -> ResolutionError
+        where F: FnOnce(Name, &str) -> ResolutionError<'_>
     {
         // If there is a TraitRef in scope for an impl, then the method must be in the
         // trait.
@@ -3092,7 +3143,7 @@ impl<'a> Resolver<'a> {
                           id: NodeId,
                           qself: Option<&QSelf>,
                           path: &Path,
-                          source: PathSource)
+                          source: PathSource<'_>)
                           -> PathResolution {
         self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
     }
@@ -3102,7 +3153,7 @@ impl<'a> Resolver<'a> {
     /// sometimes needed for the lint that recommends rewriting
     /// absolute paths to `crate`, so that it knows how to frame the
     /// suggestion. If you are just resolving a path like `foo::bar`
-    /// that appears...somewhere, though, then you just want
+    /// that appears in an arbitrary location, then you just want
     /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
     /// already provides.
     fn smart_resolve_path_with_crate_lint(
@@ -3110,7 +3161,7 @@ impl<'a> Resolver<'a> {
         id: NodeId,
         qself: Option<&QSelf>,
         path: &Path,
-        source: PathSource,
+        source: PathSource<'_>,
         crate_lint: CrateLint
     ) -> PathResolution {
         self.smart_resolve_path_fragment(
@@ -3128,340 +3179,14 @@ impl<'a> Resolver<'a> {
                                    qself: Option<&QSelf>,
                                    path: &[Segment],
                                    span: Span,
-                                   source: PathSource,
+                                   source: PathSource<'_>,
                                    crate_lint: CrateLint)
                                    -> PathResolution {
-        let ident_span = path.last().map_or(span, |ident| ident.ident.span);
         let ns = source.namespace();
         let is_expected = &|def| source.is_expected(def);
-        let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
 
-        // Base error is amended with one short label and possibly some longer helps/notes.
         let report_errors = |this: &mut Self, def: Option<Def>| {
-            // Make the base error.
-            let expected = source.descr_expected();
-            let path_str = Segment::names_to_string(path);
-            let item_str = path.last().unwrap().ident;
-            let code = source.error_code(def.is_some());
-            let (base_msg, fallback_label, base_span) = if let Some(def) = def {
-                (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
-                 format!("not a {}", expected),
-                 span)
-            } else {
-                let item_span = path.last().unwrap().ident.span;
-                let (mod_prefix, mod_str) = if path.len() == 1 {
-                    (String::new(), "this scope".to_string())
-                } else if path.len() == 2 && path[0].ident.name == keywords::PathRoot.name() {
-                    (String::new(), "the crate root".to_string())
-                } else {
-                    let mod_path = &path[..path.len() - 1];
-                    let mod_prefix = match this.resolve_path_without_parent_scope(
-                        mod_path, Some(TypeNS), false, span, CrateLint::No
-                    ) {
-                        PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
-                            module.def(),
-                        _ => None,
-                    }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
-                    (mod_prefix, format!("`{}`", Segment::names_to_string(mod_path)))
-                };
-                (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
-                 format!("not found in {}", mod_str),
-                 item_span)
-            };
-
-            let code = DiagnosticId::Error(code.into());
-            let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
-
-            // Emit help message for fake-self from other languages like `this`(javascript)
-            if ["this", "my"].contains(&&*item_str.as_str())
-                && this.self_value_is_available(path[0].ident.span, span) {
-                err.span_suggestion_with_applicability(
-                    span,
-                    "did you mean",
-                    "self".to_string(),
-                    Applicability::MaybeIncorrect,
-                );
-            }
-
-            // Emit special messages for unresolved `Self` and `self`.
-            if is_self_type(path, ns) {
-                __diagnostic_used!(E0411);
-                err.code(DiagnosticId::Error("E0411".into()));
-                err.span_label(span, format!("`Self` is only available in impls, traits, \
-                                              and type definitions"));
-                return (err, Vec::new());
-            }
-            if is_self_value(path, ns) {
-                debug!("smart_resolve_path_fragment E0424 source:{:?}", source);
-
-                __diagnostic_used!(E0424);
-                err.code(DiagnosticId::Error("E0424".into()));
-                err.span_label(span, match source {
-                    PathSource::Pat => {
-                        format!("`self` value is a keyword \
-                                and may not be bound to \
-                                variables or shadowed")
-                    }
-                    _ => {
-                        format!("`self` value is a keyword \
-                                only available in methods \
-                                with `self` parameter")
-                    }
-                });
-                return (err, Vec::new());
-            }
-
-            // Try to lookup the name in more relaxed fashion for better error reporting.
-            let ident = path.last().unwrap().ident;
-            let candidates = this.lookup_import_candidates(ident, ns, is_expected);
-            if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
-                let enum_candidates =
-                    this.lookup_import_candidates(ident, ns, is_enum_variant);
-                let mut enum_candidates = enum_candidates.iter()
-                    .map(|suggestion| {
-                        import_candidate_to_enum_paths(&suggestion)
-                    }).collect::<Vec<_>>();
-                enum_candidates.sort();
-
-                if !enum_candidates.is_empty() {
-                    // contextualize for E0412 "cannot find type", but don't belabor the point
-                    // (that it's a variant) for E0573 "expected type, found variant"
-                    let preamble = if def.is_none() {
-                        let others = match enum_candidates.len() {
-                            1 => String::new(),
-                            2 => " and 1 other".to_owned(),
-                            n => format!(" and {} others", n)
-                        };
-                        format!("there is an enum variant `{}`{}; ",
-                                enum_candidates[0].0, others)
-                    } else {
-                        String::new()
-                    };
-                    let msg = format!("{}try using the variant's enum", preamble);
-
-                    err.span_suggestions_with_applicability(
-                        span,
-                        &msg,
-                        enum_candidates.into_iter()
-                            .map(|(_variant_path, enum_ty_path)| enum_ty_path)
-                            // variants reëxported in prelude doesn't mean `prelude::v1` is the
-                            // type name! FIXME: is there a more principled way to do this that
-                            // would work for other reëxports?
-                            .filter(|enum_ty_path| enum_ty_path != "std::prelude::v1")
-                            // also say `Option` rather than `std::prelude::v1::Option`
-                            .map(|enum_ty_path| {
-                                // FIXME #56861: DRYer prelude filtering
-                                enum_ty_path.trim_start_matches("std::prelude::v1::").to_owned()
-                            }),
-                        Applicability::MachineApplicable,
-                    );
-                }
-            }
-            if path.len() == 1 && this.self_type_is_available(span) {
-                if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
-                    let self_is_available = this.self_value_is_available(path[0].ident.span, span);
-                    match candidate {
-                        AssocSuggestion::Field => {
-                            err.span_suggestion_with_applicability(
-                                span,
-                                "try",
-                                format!("self.{}", path_str),
-                                Applicability::MachineApplicable,
-                            );
-                            if !self_is_available {
-                                err.span_label(span, format!("`self` value is a keyword \
-                                                               only available in \
-                                                               methods with `self` parameter"));
-                            }
-                        }
-                        AssocSuggestion::MethodWithSelf if self_is_available => {
-                            err.span_suggestion_with_applicability(
-                                span,
-                                "try",
-                                format!("self.{}", path_str),
-                                Applicability::MachineApplicable,
-                            );
-                        }
-                        AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
-                            err.span_suggestion_with_applicability(
-                                span,
-                                "try",
-                                format!("Self::{}", path_str),
-                                Applicability::MachineApplicable,
-                            );
-                        }
-                    }
-                    return (err, candidates);
-                }
-            }
-
-            let mut levenshtein_worked = false;
-
-            // Try Levenshtein algorithm.
-            let suggestion = this.lookup_typo_candidate(path, ns, is_expected, span);
-            if let Some(suggestion) = suggestion {
-                let msg = format!(
-                    "{} {} with a similar name exists",
-                    suggestion.article, suggestion.kind
-                );
-                err.span_suggestion_with_applicability(
-                    ident_span,
-                    &msg,
-                    suggestion.candidate.to_string(),
-                    Applicability::MaybeIncorrect,
-                );
-
-                levenshtein_worked = true;
-            }
-
-            // Try context dependent help if relaxed lookup didn't work.
-            if let Some(def) = def {
-                match (def, source) {
-                    (Def::Macro(..), _) => {
-                        err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
-                        return (err, candidates);
-                    }
-                    (Def::TyAlias(..), PathSource::Trait(_)) => {
-                        err.span_label(span, "type aliases cannot be used as traits");
-                        if nightly_options::is_nightly_build() {
-                            err.note("did you mean to use a trait alias?");
-                        }
-                        return (err, candidates);
-                    }
-                    (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
-                        ExprKind::Field(_, ident) => {
-                            err.span_label(parent.span, format!("did you mean `{}::{}`?",
-                                                                 path_str, ident));
-                            return (err, candidates);
-                        }
-                        ExprKind::MethodCall(ref segment, ..) => {
-                            err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
-                                                                 path_str, segment.ident));
-                            return (err, candidates);
-                        }
-                        _ => {}
-                    },
-                    (Def::Enum(..), PathSource::TupleStruct)
-                        | (Def::Enum(..), PathSource::Expr(..))  => {
-                        if let Some(variants) = this.collect_enum_variants(def) {
-                            err.note(&format!("did you mean to use one \
-                                               of the following variants?\n{}",
-                                variants.iter()
-                                    .map(|suggestion| path_names_to_string(suggestion))
-                                    .map(|suggestion| format!("- `{}`", suggestion))
-                                    .collect::<Vec<_>>()
-                                    .join("\n")));
-
-                        } else {
-                            err.note("did you mean to use one of the enum's variants?");
-                        }
-                        return (err, candidates);
-                    },
-                    (Def::Struct(def_id), _) if ns == ValueNS => {
-                        if let Some((ctor_def, ctor_vis))
-                                = this.struct_constructors.get(&def_id).cloned() {
-                            let accessible_ctor = this.is_accessible(ctor_vis);
-                            if is_expected(ctor_def) && !accessible_ctor {
-                                err.span_label(span, format!("constructor is not visible \
-                                                              here due to private fields"));
-                            }
-                        } else {
-                            // HACK(estebank): find a better way to figure out that this was a
-                            // parser issue where a struct literal is being used on an expression
-                            // where a brace being opened means a block is being started. Look
-                            // ahead for the next text to see if `span` is followed by a `{`.
-                            let sm = this.session.source_map();
-                            let mut sp = span;
-                            loop {
-                                sp = sm.next_point(sp);
-                                match sm.span_to_snippet(sp) {
-                                    Ok(ref snippet) => {
-                                        if snippet.chars().any(|c| { !c.is_whitespace() }) {
-                                            break;
-                                        }
-                                    }
-                                    _ => break,
-                                }
-                            }
-                            let followed_by_brace = match sm.span_to_snippet(sp) {
-                                Ok(ref snippet) if snippet == "{" => true,
-                                _ => false,
-                            };
-                            match source {
-                                PathSource::Expr(Some(parent)) => {
-                                    match parent.node {
-                                        ExprKind::MethodCall(ref path_assignment, _)  => {
-                                            err.span_suggestion_with_applicability(
-                                                sm.start_point(parent.span)
-                                                  .to(path_assignment.ident.span),
-                                                "use `::` to access an associated function",
-                                                format!("{}::{}",
-                                                        path_str,
-                                                        path_assignment.ident),
-                                                Applicability::MaybeIncorrect
-                                            );
-                                            return (err, candidates);
-                                        },
-                                        _ => {
-                                            err.span_label(
-                                                span,
-                                                format!("did you mean `{} {{ /* fields */ }}`?",
-                                                        path_str),
-                                            );
-                                            return (err, candidates);
-                                        },
-                                    }
-                                },
-                                PathSource::Expr(None) if followed_by_brace == true => {
-                                    err.span_label(
-                                        span,
-                                        format!("did you mean `({} {{ /* fields */ }})`?",
-                                                path_str),
-                                    );
-                                    return (err, candidates);
-                                },
-                                _ => {
-                                    err.span_label(
-                                        span,
-                                        format!("did you mean `{} {{ /* fields */ }}`?",
-                                                path_str),
-                                    );
-                                    return (err, candidates);
-                                },
-                            }
-                        }
-                        return (err, candidates);
-                    }
-                    (Def::Union(..), _) |
-                    (Def::Variant(..), _) |
-                    (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
-                        err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
-                                                     path_str));
-                        return (err, candidates);
-                    }
-                    (Def::SelfTy(..), _) if ns == ValueNS => {
-                        err.span_label(span, fallback_label);
-                        err.note("can't use `Self` as a constructor, you must use the \
-                                  implemented struct");
-                        return (err, candidates);
-                    }
-                    (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
-                        err.note("can't use a type alias as a constructor");
-                        return (err, candidates);
-                    }
-                    _ => {}
-                }
-            }
-
-            // Fallback label.
-            if !levenshtein_worked {
-                err.span_label(base_span, fallback_label);
-                this.type_ascription_suggestion(&mut err, base_span);
-            }
-            (err, candidates)
-        };
-        let report_errors = |this: &mut Self, def: Option<Def>| {
-            let (err, candidates) = report_errors(this, def);
+            let (err, candidates) = this.smart_resolve_report_errors(path, span, source, def);
             let def_id = this.current_module.normal_ancestor_id;
             let node_id = this.definitions.as_local_node_id(def_id).unwrap();
             let better = def.is_some();
@@ -3525,14 +3250,15 @@ impl<'a> Resolver<'a> {
     }
 
     fn type_ascription_suggestion(&self,
-                                  err: &mut DiagnosticBuilder,
+                                  err: &mut DiagnosticBuilder<'_>,
                                   base_span: Span) {
         debug!("type_ascription_suggetion {:?}", base_span);
         let cm = self.session.source_map();
         debug!("self.current_type_ascription {:?}", self.current_type_ascription);
         if let Some(sp) = self.current_type_ascription.last() {
             let mut sp = *sp;
-            loop {  // try to find the `:`, bail on first non-':'/non-whitespace
+            loop {
+                // Try to find the `:`; bail on first non-':' / non-whitespace.
                 sp = cm.next_point(sp);
                 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
                     debug!("snippet {:?}", snippet);
@@ -3543,7 +3269,7 @@ impl<'a> Resolver<'a> {
                         err.span_label(base_span,
                                        "expecting a type here because of type ascription");
                         if line_sp != line_base_sp {
-                            err.span_suggestion_short_with_applicability(
+                            err.span_suggestion_short(
                                 sp,
                                 "did you mean to use `;` here instead?",
                                 ";".to_string(),
@@ -3984,7 +3710,7 @@ impl<'a> Resolver<'a> {
         crate_lint: CrateLint,
         path: &[Segment],
         path_span: Span,
-        second_binding: Option<&NameBinding>,
+        second_binding: Option<&NameBinding<'_>>,
     ) {
         let (diag_id, diag_span) = match crate_lint {
             CrateLint::No => return,
@@ -4046,6 +3772,7 @@ impl<'a> Resolver<'a> {
                         mut def: Def,
                         record_used: bool,
                         span: Span) -> Def {
+        debug!("adjust_local_def");
         let ribs = &self.ribs[ns][rib_index + 1..];
 
         // An invalid forward use of a type parameter from a previous default.
@@ -4062,6 +3789,9 @@ impl<'a> Resolver<'a> {
                 span_bug!(span, "unexpected {:?} in bindings", def)
             }
             Def::Local(node_id) => {
+                use ResolutionError::*;
+                let mut res_err = None;
+
                 for rib in ribs {
                     match rib.kind {
                         NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
@@ -4097,21 +3827,26 @@ impl<'a> Resolver<'a> {
                             // named function item. This is not allowed, so we
                             // report an error.
                             if record_used {
-                                resolve_error(self, span,
-                                    ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
+                                // We don't immediately trigger a resolve error, because
+                                // we want certain other resolution errors (namely those
+                                // emitted for `ConstantItemRibKind` below) to take
+                                // precedence.
+                                res_err = Some(CannotCaptureDynamicEnvironmentInFnItem);
                             }
-                            return Def::Err;
                         }
                         ConstantItemRibKind => {
                             // Still doesn't deal with upvars
                             if record_used {
-                                resolve_error(self, span,
-                                    ResolutionError::AttemptToUseNonConstantValueInConstant);
+                                resolve_error(self, span, AttemptToUseNonConstantValueInConstant);
                             }
                             return Def::Err;
                         }
                     }
                 }
+                if let Some(res_err) = res_err {
+                     resolve_error(self, span, res_err);
+                     return Def::Err;
+                }
             }
             Def::TyParam(..) | Def::SelfTy(..) => {
                 for rib in ribs {
@@ -4122,17 +3857,38 @@ impl<'a> Resolver<'a> {
                             // Nothing to do. Continue.
                         }
                         ItemRibKind => {
-                            // This was an attempt to use a type parameter outside
-                            // its scope.
+                            // This was an attempt to use a type parameter outside its scope.
                             if record_used {
-                                resolve_error(self, span,
-                                    ResolutionError::TypeParametersFromOuterFunction(def));
+                                resolve_error(
+                                    self,
+                                    span,
+                                    ResolutionError::GenericParamsFromOuterFunction(def),
+                                );
                             }
                             return Def::Err;
                         }
                     }
                 }
             }
+            Def::ConstParam(..) => {
+                // A const param is always declared in a signature, which is always followed by
+                // some kind of function rib kind (specifically, ItemRibKind in the case of a
+                // normal function), so we can skip the first rib as it will be guaranteed to
+                // (spuriously) conflict with the const param.
+                for rib in &ribs[1..] {
+                    if let ItemRibKind = rib.kind {
+                        // This was an attempt to use a const parameter outside its scope.
+                        if record_used {
+                            resolve_error(
+                                self,
+                                span,
+                                ResolutionError::GenericParamsFromOuterFunction(def),
+                            );
+                        }
+                        return Def::Err;
+                    }
+                }
+            }
             _ => {}
         }
         def
@@ -4210,7 +3966,7 @@ impl<'a> Resolver<'a> {
     where
         FilterFn: Fn(Def) -> bool,
     {
-        let add_module_candidates = |module: Module, names: &mut Vec<TypoSuggestion>| {
+        let add_module_candidates = |module: Module<'_>, names: &mut Vec<TypoSuggestion>| {
             for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
                 if let Some(binding) = resolution.borrow().binding {
                     if filter_fn(binding.def()) {
@@ -4305,7 +4061,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
-        where F: FnOnce(&mut Resolver)
+        where F: FnOnce(&mut Resolver<'_>)
     {
         if let Some(label) = label {
             self.unused_labels.insert(id, label.ident.span);
@@ -4635,7 +4391,8 @@ impl<'a> Resolver<'a> {
 
                 // collect results based on the filter function
                 if ident.name == lookup_ident.name && ns == namespace {
-                    if filter_fn(name_binding.def()) {
+                    let def = name_binding.def();
+                    if filter_fn(def) {
                         // create the path
                         let mut segms = path_segments.clone();
                         if lookup_ident.span.rust_2018() {
@@ -4659,7 +4416,12 @@ impl<'a> Resolver<'a> {
                         // declared as public (due to pruning, we don't explore
                         // outside crate private modules => no need to check this)
                         if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
-                            candidates.push(ImportSuggestion { path });
+                            let did = match def {
+                                Def::StructCtor(did, _) | Def::VariantCtor(did, _) =>
+                                    self.parent(did),
+                                _ => def.opt_def_id(),
+                            };
+                            candidates.push(ImportSuggestion { did, path });
                         }
                     }
                 }
@@ -4694,9 +4456,9 @@ impl<'a> Resolver<'a> {
     /// When name resolution fails, this method can be used to look up candidate
     /// entities with the expected name. It allows filtering them using the
     /// supplied predicate (which should be used to only accept the types of
-    /// definitions expected e.g., traits). The lookup spans across all crates.
+    /// definitions expected, e.g., traits). The lookup spans across all crates.
     ///
-    /// NOTE: The method does not look into imports, but this is not a problem,
+    /// N.B., the method does not look into imports, but this is not a problem,
     /// since we report the definitions (thus, the de-aliased imports).
     fn lookup_import_candidates<FilterFn>(&mut self,
                                           lookup_ident: Ident,
@@ -4756,7 +4518,8 @@ impl<'a> Resolver<'a> {
                             span: name_binding.span,
                             segments: path_segments,
                         };
-                        result = Some((module, ImportSuggestion { path }));
+                        let did = module.def().and_then(|def| def.opt_def_id());
+                        result = Some((module, ImportSuggestion { did, path }));
                     } else {
                         // add the module to the lookup
                         if seen_modules.insert(module.def_id().unwrap()) {
@@ -4820,8 +4583,13 @@ impl<'a> Resolver<'a> {
                 } else if ident.span.rust_2018() {
                     let msg = "relative paths are not supported in visibilities on 2018 edition";
                     self.session.struct_span_err(ident.span, msg)
-                                .span_suggestion(path.span, "try", format!("crate::{}", path))
-                                .emit();
+                        .span_suggestion(
+                            path.span,
+                            "try",
+                            format!("crate::{}", path),
+                            Applicability::MaybeIncorrect,
+                        )
+                        .emit();
                     return ty::Visibility::Public;
                 } else {
                     let ctxt = ident.span.ctxt();
@@ -4889,7 +4657,7 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    fn binding_description(&self, b: &NameBinding, ident: Ident, from_prelude: bool) -> String {
+    fn binding_description(&self, b: &NameBinding<'_>, ident: Ident, from_prelude: bool) -> String {
         if b.span.is_dummy() {
             let add_built_in = match b.def() {
                 // These already contain the "built-in" prefix or look bad with it.
@@ -4917,7 +4685,7 @@ impl<'a> Resolver<'a> {
         }
     }
 
-    fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError) {
+    fn report_ambiguity_error(&self, ambiguity_error: &AmbiguityError<'_>) {
         let AmbiguityError { kind, ident, b1, b2, misc1, misc2 } = *ambiguity_error;
         let (b1, b2, misc1, misc2, swapped) = if b2.span.is_dummy() && !b1.span.is_dummy() {
             // We have to print the span-less alternative first, otherwise formatting looks bad.
@@ -4931,7 +4699,7 @@ impl<'a> Resolver<'a> {
                                        ident = ident, why = kind.descr());
         err.span_label(ident.span, "ambiguous name");
 
-        let mut could_refer_to = |b: &NameBinding, misc: AmbiguityErrorMisc, also: &str| {
+        let mut could_refer_to = |b: &NameBinding<'_>, misc: AmbiguityErrorMisc, also: &str| {
             let what = self.binding_description(b, ident, misc == AmbiguityErrorMisc::FromPrelude);
             let note_msg = format!("`{ident}` could{also} refer to {what}",
                                    ident = ident, also = also, what = what);
@@ -4962,11 +4730,7 @@ impl<'a> Resolver<'a> {
                 ))
             }
 
-            if b.span.is_dummy() {
-                err.note(&note_msg);
-            } else {
-                err.span_note(b.span, &note_msg);
-            }
+            err.span_note(b.span, &note_msg);
             for (i, help_msg) in help_msgs.iter().enumerate() {
                 let or = if i == 0 { "" } else { "or " };
                 err.help(&format!("{}{}", or, help_msg));
@@ -5016,7 +4780,7 @@ impl<'a> Resolver<'a> {
     }
 
     fn report_conflict<'b>(&mut self,
-                       parent: Module,
+                       parent: Module<'_>,
                        ident: Ident,
                        ns: Namespace,
                        new_binding: &NameBinding<'b>,
@@ -5081,73 +4845,243 @@ impl<'a> Resolver<'a> {
                           container));
 
         err.span_label(span, format!("`{}` re{} here", name, new_participle));
-        if !old_binding.span.is_dummy() {
-            err.span_label(self.session.source_map().def_span(old_binding.span),
-                           format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
-        }
+        err.span_label(
+            self.session.source_map().def_span(old_binding.span),
+            format!("previous {} of the {} `{}` here", old_noun, old_kind, name),
+        );
 
         // See https://github.com/rust-lang/rust/issues/32354
-        if old_binding.is_import() || new_binding.is_import() {
-            let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
-                new_binding
-            } else {
-                old_binding
-            };
-
-            let cm = self.session.source_map();
-            let rename_msg = "you can use `as` to change the binding name of the import";
-
-            if let (
-                Ok(snippet),
-                NameBindingKind::Import { directive, ..},
-                _dummy @ false,
-            ) = (
-                cm.span_to_snippet(binding.span),
-                binding.kind.clone(),
-                binding.span.is_dummy(),
-            ) {
-                let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
-                    format!("Other{}", name)
+        use NameBindingKind::Import;
+        let directive = match (&new_binding.kind, &old_binding.kind) {
+            // If there are two imports where one or both have attributes then prefer removing the
+            // import without attributes.
+            (Import { directive: new, .. }, Import { directive: old, .. }) if {
+                !new_binding.span.is_dummy() && !old_binding.span.is_dummy() &&
+                    (new.has_attributes || old.has_attributes)
+            } => {
+                if old.has_attributes {
+                    Some((new, new_binding.span, true))
                 } else {
-                    format!("other_{}", name)
-                };
+                    Some((old, old_binding.span, true))
+                }
+            },
+            // Otherwise prioritize the new binding.
+            (Import { directive, .. }, other) if !new_binding.span.is_dummy() =>
+                Some((directive, new_binding.span, other.is_import())),
+            (other, Import { directive, .. }) if !old_binding.span.is_dummy() =>
+                Some((directive, old_binding.span, other.is_import())),
+            _ => None,
+        };
 
-                err.span_suggestion_with_applicability(
-                    binding.span,
-                    &rename_msg,
-                    match directive.subclass {
-                        ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
-                            format!("self as {}", suggested_name),
-                        ImportDirectiveSubclass::SingleImport { source, .. } =>
-                            format!(
-                                "{} as {}{}",
-                                &snippet[..((source.span.hi().0 - binding.span.lo().0) as usize)],
-                                suggested_name,
-                                if snippet.ends_with(";") {
-                                    ";"
-                                } else {
-                                    ""
-                                }
-                            ),
-                        ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
-                            format!(
-                                "extern crate {} as {};",
-                                source.unwrap_or(target.name),
-                                suggested_name,
-                            ),
-                        _ => unreachable!(),
-                    },
+        // Check if the target of the use for both bindings is the same.
+        let duplicate = new_binding.def().opt_def_id() == old_binding.def().opt_def_id();
+        let has_dummy_span = new_binding.span.is_dummy() || old_binding.span.is_dummy();
+        let from_item = self.extern_prelude.get(&ident)
+            .map(|entry| entry.introduced_by_item)
+            .unwrap_or(true);
+        // Only suggest removing an import if both bindings are to the same def, if both spans
+        // aren't dummy spans. Further, if both bindings are imports, then the ident must have
+        // been introduced by a item.
+        let should_remove_import = duplicate && !has_dummy_span &&
+            ((new_binding.is_extern_crate() || old_binding.is_extern_crate()) || from_item);
+
+        match directive {
+            Some((directive, span, true)) if should_remove_import && directive.is_nested() =>
+                self.add_suggestion_for_duplicate_nested_use(&mut err, directive, span),
+            Some((directive, _, true)) if should_remove_import && !directive.is_glob() => {
+                // Simple case - remove the entire import. Due to the above match arm, this can
+                // only be a single use so just remove it entirely.
+                err.span_suggestion(
+                    directive.use_span_with_attributes,
+                    "remove unnecessary import",
+                    String::new(),
                     Applicability::MaybeIncorrect,
                 );
-            } else {
-                err.span_label(binding.span, rename_msg);
-            }
+            },
+            Some((directive, span, _)) =>
+                self.add_suggestion_for_rename_of_use(&mut err, name, directive, span),
+            _ => {},
         }
 
         err.emit();
         self.name_already_seen.insert(name, span);
     }
 
+    /// This function adds a suggestion to change the binding name of a new import that conflicts
+    /// with an existing import.
+    ///
+    /// ```ignore (diagnostic)
+    /// help: you can use `as` to change the binding name of the import
+    ///    |
+    /// LL | use foo::bar as other_bar;
+    ///    |     ^^^^^^^^^^^^^^^^^^^^^
+    /// ```
+    fn add_suggestion_for_rename_of_use(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        name: Symbol,
+        directive: &ImportDirective<'_>,
+        binding_span: Span,
+    ) {
+        let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
+            format!("Other{}", name)
+        } else {
+            format!("other_{}", name)
+        };
+
+        let mut suggestion = None;
+        match directive.subclass {
+            ImportDirectiveSubclass::SingleImport { type_ns_only: true, .. } =>
+                suggestion = Some(format!("self as {}", suggested_name)),
+            ImportDirectiveSubclass::SingleImport { source, .. } => {
+                if let Some(pos) = source.span.hi().0.checked_sub(binding_span.lo().0)
+                                                     .map(|pos| pos as usize) {
+                    if let Ok(snippet) = self.session.source_map()
+                                                     .span_to_snippet(binding_span) {
+                        if pos <= snippet.len() {
+                            suggestion = Some(format!(
+                                "{} as {}{}",
+                                &snippet[..pos],
+                                suggested_name,
+                                if snippet.ends_with(";") { ";" } else { "" }
+                            ))
+                        }
+                    }
+                }
+            }
+            ImportDirectiveSubclass::ExternCrate { source, target, .. } =>
+                suggestion = Some(format!(
+                    "extern crate {} as {};",
+                    source.unwrap_or(target.name),
+                    suggested_name,
+                )),
+            _ => unreachable!(),
+        }
+
+        let rename_msg = "you can use `as` to change the binding name of the import";
+        if let Some(suggestion) = suggestion {
+            err.span_suggestion(
+                binding_span,
+                rename_msg,
+                suggestion,
+                Applicability::MaybeIncorrect,
+            );
+        } else {
+            err.span_label(binding_span, rename_msg);
+        }
+    }
+
+    /// This function adds a suggestion to remove a unnecessary binding from an import that is
+    /// nested. In the following example, this function will be invoked to remove the `a` binding
+    /// in the second use statement:
+    ///
+    /// ```ignore (diagnostic)
+    /// use issue_52891::a;
+    /// use issue_52891::{d, a, e};
+    /// ```
+    ///
+    /// The following suggestion will be added:
+    ///
+    /// ```ignore (diagnostic)
+    /// use issue_52891::{d, a, e};
+    ///                      ^-- help: remove unnecessary import
+    /// ```
+    ///
+    /// If the nested use contains only one import then the suggestion will remove the entire
+    /// line.
+    ///
+    /// It is expected that the directive provided is a nested import - this isn't checked by the
+    /// function. If this invariant is not upheld, this function's behaviour will be unexpected
+    /// as characters expected by span manipulations won't be present.
+    fn add_suggestion_for_duplicate_nested_use(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        directive: &ImportDirective<'_>,
+        binding_span: Span,
+    ) {
+        assert!(directive.is_nested());
+        let message = "remove unnecessary import";
+        let source_map = self.session.source_map();
+
+        // Two examples will be used to illustrate the span manipulations we're doing:
+        //
+        // - Given `use issue_52891::{d, a, e};` where `a` is a duplicate then `binding_span` is
+        //   `a` and `directive.use_span` is `issue_52891::{d, a, e};`.
+        // - Given `use issue_52891::{d, e, a};` where `a` is a duplicate then `binding_span` is
+        //   `a` and `directive.use_span` is `issue_52891::{d, e, a};`.
+
+        // Find the span of everything after the binding.
+        //   ie. `a, e};` or `a};`
+        let binding_until_end = binding_span.with_hi(directive.use_span.hi());
+
+        // Find everything after the binding but not including the binding.
+        //   ie. `, e};` or `};`
+        let after_binding_until_end = binding_until_end.with_lo(binding_span.hi());
+
+        // Keep characters in the span until we encounter something that isn't a comma or
+        // whitespace.
+        //   ie. `, ` or ``.
+        //
+        // Also note whether a closing brace character was encountered. If there
+        // was, then later go backwards to remove any trailing commas that are left.
+        let mut found_closing_brace = false;
+        let after_binding_until_next_binding = source_map.span_take_while(
+            after_binding_until_end,
+            |&ch| {
+                if ch == '}' { found_closing_brace = true; }
+                ch == ' ' || ch == ','
+            }
+        );
+
+        // Combine the two spans.
+        //   ie. `a, ` or `a`.
+        //
+        // Removing these would leave `issue_52891::{d, e};` or `issue_52891::{d, e, };`
+        let span = binding_span.with_hi(after_binding_until_next_binding.hi());
+
+        // If there was a closing brace then identify the span to remove any trailing commas from
+        // previous imports.
+        if found_closing_brace {
+            if let Ok(prev_source) = source_map.span_to_prev_source(span) {
+                // `prev_source` will contain all of the source that came before the span.
+                // Then split based on a command and take the first (ie. closest to our span)
+                // snippet. In the example, this is a space.
+                let prev_comma = prev_source.rsplit(',').collect::<Vec<_>>();
+                let prev_starting_brace = prev_source.rsplit('{').collect::<Vec<_>>();
+                if prev_comma.len() > 1 && prev_starting_brace.len() > 1 {
+                    let prev_comma = prev_comma.first().unwrap();
+                    let prev_starting_brace = prev_starting_brace.first().unwrap();
+
+                    // If the amount of source code before the comma is greater than
+                    // the amount of source code before the starting brace then we've only
+                    // got one item in the nested item (eg. `issue_52891::{self}`).
+                    if prev_comma.len() > prev_starting_brace.len() {
+                        // So just remove the entire line...
+                        err.span_suggestion(
+                            directive.use_span_with_attributes,
+                            message,
+                            String::new(),
+                            Applicability::MaybeIncorrect,
+                        );
+                        return;
+                    }
+
+                    let span = span.with_lo(BytePos(
+                        // Take away the number of bytes for the characters we've found and an
+                        // extra for the comma.
+                        span.lo().0 - (prev_comma.as_bytes().len() as u32) - 1
+                    ));
+                    err.span_suggestion(
+                        span, message, String::new(), Applicability::MaybeIncorrect,
+                    );
+                    return;
+                }
+            }
+        }
+
+        err.span_suggestion(span, message, String::new(), Applicability::MachineApplicable);
+    }
+
     fn extern_prelude_get(&mut self, ident: Ident, speculative: bool)
                           -> Option<&'a NameBinding<'a>> {
         if ident.is_path_segment_keyword() {
@@ -5205,7 +5139,7 @@ fn path_names_to_string(path: &Path) -> String {
                         .collect::<Vec<_>>())
 }
 
-/// Get the stringified path for an enum from an `ImportSuggestion` for an enum variant.
+/// Gets the stringified path for an enum from an `ImportSuggestion` for an enum variant.
 fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, String) {
     let variant_path = &suggestion.path;
     let variant_path_string = path_names_to_string(variant_path);
@@ -5220,11 +5154,10 @@ fn import_candidate_to_enum_paths(suggestion: &ImportSuggestion) -> (String, Str
     (variant_path_string, enum_path_string)
 }
 
-
 /// When an entity with a given name is not available in scope, we search for
 /// entities with that name in all crates. This method allows outputting the
 /// results of this search in a programmer-friendly way
-fn show_candidates(err: &mut DiagnosticBuilder,
+fn show_candidates(err: &mut DiagnosticBuilder<'_>,
                    // This is `None` if all placement locations are inside expansions
                    span: Option<Span>,
                    candidates: &[ImportSuggestion],
@@ -5256,7 +5189,7 @@ fn show_candidates(err: &mut DiagnosticBuilder,
             *candidate = format!("use {};\n{}", candidate, additional_newline);
         }
 
-        err.span_suggestions_with_applicability(
+        err.span_suggestions(
             span,
             &msg,
             path_strings.into_iter(),
@@ -5273,10 +5206,10 @@ fn show_candidates(err: &mut DiagnosticBuilder,
 }
 
 /// A somewhat inefficient routine to obtain the name of a module.
-fn module_to_string(module: Module) -> Option<String> {
+fn module_to_string(module: Module<'_>) -> Option<String> {
     let mut names = Vec::new();
 
-    fn collect_mod(names: &mut Vec<Ident>, module: Module) {
+    fn collect_mod(names: &mut Vec<Ident>, module: Module<'_>) {
         if let ModuleKind::Def(_, name) = module.kind {
             if let Some(parent) = module.parent {
                 names.push(Ident::with_empty_ctxt(name));
@@ -5304,11 +5237,11 @@ fn err_path_resolution() -> PathResolution {
 
 #[derive(Copy, Clone, Debug)]
 enum CrateLint {
-    /// Do not issue the lint
+    /// Do not issue the lint.
     No,
 
-    /// This lint applies to some random path like `impl ::foo::Bar`
-    /// or whatever. In this case, we can take the span of that path.
+    /// This lint applies to some arbitrary path; e.g., `impl ::foo::Bar`.
+    /// In this case, we can take the span of that path.
     SimplePath(NodeId),
 
     /// This lint comes from a `use` statement. In this case, what we
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 286f9a758830b..63f752ac9c942 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -1,25 +1,28 @@
-use {AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
-use {CrateLint, Resolver, ResolutionError, ScopeSet, Weak};
-use {Module, ModuleKind, NameBinding, NameBindingKind, PathResult, Segment, ToNameBinding};
-use {is_known_tool, resolve_error};
-use ModuleOrUniformRoot;
-use Namespace::*;
-use build_reduced_graph::{BuildReducedGraphVisitor, IsMacroExport};
-use resolve_imports::ImportResolver;
+use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
+use crate::{CrateLint, Resolver, ResolutionError, ScopeSet, Weak};
+use crate::{Module, ModuleKind, NameBinding, NameBindingKind, PathResult, Segment, ToNameBinding};
+use crate::{is_known_tool, resolve_error};
+use crate::ModuleOrUniformRoot;
+use crate::Namespace::*;
+use crate::build_reduced_graph::{BuildReducedGraphVisitor, IsMacroExport};
+use crate::resolve_imports::ImportResolver;
 use rustc::hir::def_id::{DefId, CRATE_DEF_INDEX, DefIndex,
                          CrateNum, DefIndexAddressSpace};
 use rustc::hir::def::{Def, NonMacroAttrKind};
 use rustc::hir::map::{self, DefCollector};
 use rustc::{ty, lint};
+use rustc::{bug, span_bug};
 use syntax::ast::{self, Ident};
 use syntax::attr;
 use syntax::errors::DiagnosticBuilder;
 use syntax::ext::base::{self, Determinacy};
-use syntax::ext::base::{Annotatable, MacroKind, SyntaxExtension};
+use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::expand::{AstFragment, Invocation, InvocationKind};
 use syntax::ext::hygiene::{self, Mark};
 use syntax::ext::tt::macro_rules;
-use syntax::feature_gate::{feature_err, is_builtin_attr_name, GateIssue};
+use syntax::feature_gate::{
+    feature_err, is_builtin_attr_name, AttributeGate, GateIssue, Stability, BUILTIN_ATTRIBUTES,
+};
 use syntax::symbol::{Symbol, keywords};
 use syntax::visit::Visitor;
 use syntax::util::lev_distance::find_best_match_for_name;
@@ -33,12 +36,12 @@ use rustc_data_structures::sync::Lrc;
 #[derive(Clone, Debug)]
 pub struct InvocationData<'a> {
     def_index: DefIndex,
-    /// Module in which the macro was invoked.
+    /// The module in which the macro was invoked.
     crate module: Cell<Module<'a>>,
-    /// Legacy scope in which the macro was invoked.
+    /// The legacy scope in which the macro was invoked.
     /// The invocation path is resolved in this scope.
     crate parent_legacy_scope: Cell<LegacyScope<'a>>,
-    /// Legacy scope *produced* by expanding this macro invocation,
+    /// The legacy scope *produced* by expanding this macro invocation,
     /// includes all the macro_rules items, other invocations, etc generated by it.
     /// `None` if the macro is not expanded yet.
     crate output_legacy_scope: Cell<Option<LegacyScope<'a>>>,
@@ -65,21 +68,21 @@ pub struct LegacyBinding<'a> {
     ident: Ident,
 }
 
-/// Scope introduced by a `macro_rules!` macro.
-/// Starts at the macro's definition and ends at the end of the macro's parent module
-/// (named or unnamed), or even further if it escapes with `#[macro_use]`.
+/// The scope introduced by a `macro_rules!` macro.
+/// This starts at the macro's definition and ends at the end of the macro's parent
+/// module (named or unnamed), or even further if it escapes with `#[macro_use]`.
 /// Some macro invocations need to introduce legacy scopes too because they
-/// potentially can expand into macro definitions.
+/// can potentially expand into macro definitions.
 #[derive(Copy, Clone, Debug)]
 pub enum LegacyScope<'a> {
-    /// Created when invocation data is allocated in the arena,
+    /// Created when invocation data is allocated in the arena;
     /// must be replaced with a proper scope later.
     Uninitialized,
     /// Empty "root" scope at the crate start containing no names.
     Empty,
-    /// Scope introduced by a `macro_rules!` macro definition.
+    /// The scope introduced by a `macro_rules!` macro definition.
     Binding(&'a LegacyBinding<'a>),
-    /// Scope introduced by a macro invocation that can potentially
+    /// The scope introduced by a macro invocation that can potentially
     /// create a `macro_rules!` macro definition.
     Invocation(&'a InvocationData<'a>),
 }
@@ -127,9 +130,9 @@ impl<'a> base::Resolver for Resolver<'a> {
         mark
     }
 
-    fn resolve_dollar_crates(&mut self, annotatable: &Annotatable) {
-        pub struct ResolveDollarCrates<'a, 'b: 'a> {
-            pub resolver: &'a mut Resolver<'b>,
+    fn resolve_dollar_crates(&mut self, fragment: &AstFragment) {
+        struct ResolveDollarCrates<'a, 'b: 'a> {
+            resolver: &'a mut Resolver<'b>
         }
         impl<'a> Visitor<'a> for ResolveDollarCrates<'a, '_> {
             fn visit_ident(&mut self, ident: Ident) {
@@ -144,7 +147,7 @@ impl<'a> base::Resolver for Resolver<'a> {
             fn visit_mac(&mut self, _: &ast::Mac) {}
         }
 
-        annotatable.visit_with(&mut ResolveDollarCrates { resolver: self });
+        fragment.visit_with(&mut ResolveDollarCrates { resolver: self });
     }
 
     fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
@@ -310,15 +313,18 @@ impl<'a> Resolver<'a> {
                             if !features.rustc_attrs {
                                 let msg = "unless otherwise specified, attributes with the prefix \
                                            `rustc_` are reserved for internal compiler diagnostics";
-                                feature_err(&self.session.parse_sess, "rustc_attrs", path.span,
-                                            GateIssue::Language, &msg).emit();
+                                self.report_unknown_attribute(path.span, &name, msg, "rustc_attrs");
                             }
                         } else if !features.custom_attribute {
                             let msg = format!("The attribute `{}` is currently unknown to the \
                                                compiler and may have meaning added to it in the \
                                                future", path);
-                            feature_err(&self.session.parse_sess, "custom_attribute", path.span,
-                                        GateIssue::Language, &msg).emit();
+                            self.report_unknown_attribute(
+                                path.span,
+                                &name,
+                                &msg,
+                                "custom_attribute",
+                            );
                         }
                     }
                 } else {
@@ -339,6 +345,61 @@ impl<'a> Resolver<'a> {
         Ok((def, self.get_macro(def)))
     }
 
+    fn report_unknown_attribute(&self, span: Span, name: &str, msg: &str, feature: &str) {
+        let mut err = feature_err(
+            &self.session.parse_sess,
+            feature,
+            span,
+            GateIssue::Language,
+            &msg,
+        );
+
+        let features = self.session.features_untracked();
+
+        let attr_candidates = BUILTIN_ATTRIBUTES
+            .iter()
+            .filter_map(|(name, _, _, gate)| {
+                if name.starts_with("rustc_") && !features.rustc_attrs {
+                    return None;
+                }
+
+                match gate {
+                    AttributeGate::Gated(Stability::Unstable, ..)
+                        if self.session.opts.unstable_features.is_nightly_build() =>
+                    {
+                        Some(name)
+                    }
+                    AttributeGate::Gated(Stability::Deprecated(..), ..) => Some(name),
+                    AttributeGate::Ungated => Some(name),
+                    _ => None,
+                }
+            })
+            .map(|name| Symbol::intern(name))
+            .chain(
+                // Add built-in macro attributes as well.
+                self.builtin_macros.iter().filter_map(|(name, binding)| {
+                    match binding.macro_kind() {
+                        Some(MacroKind::Attr) => Some(*name),
+                        _ => None,
+                    }
+                }),
+            )
+            .collect::<Vec<_>>();
+
+        let lev_suggestion = find_best_match_for_name(attr_candidates.iter(), &name, None);
+
+        if let Some(suggestion) = lev_suggestion {
+            err.span_suggestion(
+                span,
+                "a built-in attribute with a similar name exists",
+                suggestion.to_string(),
+                Applicability::MaybeIncorrect,
+            );
+        }
+
+        err.emit();
+    }
+
     pub fn resolve_macro_to_def_inner(
         &mut self,
         path: &ast::Path,
@@ -470,7 +531,7 @@ impl<'a> Resolver<'a> {
             BuiltinTypes,
         }
 
-        bitflags! {
+        bitflags::bitflags! {
             struct Flags: u8 {
                 const MACRO_RULES        = 1 << 0;
                 const MODULE             = 1 << 1;
@@ -500,7 +561,7 @@ impl<'a> Resolver<'a> {
         // }
         // So we have to save the innermost solution and continue searching in outer scopes
         // to detect potential ambiguities.
-        let mut innermost_result: Option<(&NameBinding, Flags)> = None;
+        let mut innermost_result: Option<(&NameBinding<'_>, Flags)> = None;
 
         // Go through all the scopes and try to resolve the name.
         let rust_2015 = orig_ident.span.rust_2015();
@@ -1021,14 +1082,14 @@ impl<'a> Resolver<'a> {
         if let Some(suggestion) = suggestion {
             if suggestion != name {
                 if let MacroKind::Bang = kind {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "you could try the macro",
                         suggestion.to_string(),
                         Applicability::MaybeIncorrect
                     );
                 } else {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "try",
                         suggestion.to_string(),
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index fd55897522bf7..b930c30c51192 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -1,13 +1,13 @@
-use self::ImportDirectiveSubclass::*;
+use ImportDirectiveSubclass::*;
 
-use {AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
-use {CrateLint, Module, ModuleOrUniformRoot, PerNS, ScopeSet, Weak};
-use Namespace::{self, TypeNS, MacroNS};
-use {NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError};
-use {Resolver, Segment};
-use {names_to_string, module_to_string};
-use {resolve_error, ResolutionError};
-use macros::ParentScope;
+use crate::{AmbiguityError, AmbiguityKind, AmbiguityErrorMisc};
+use crate::{CrateLint, Module, ModuleOrUniformRoot, PerNS, ScopeSet, Weak};
+use crate::Namespace::{self, TypeNS, MacroNS};
+use crate::{NameBinding, NameBindingKind, ToNameBinding, PathResult, PrivacyError};
+use crate::{Resolver, Segment};
+use crate::{names_to_string, module_to_string};
+use crate::{resolve_error, ResolutionError};
+use crate::macros::ParentScope;
 
 use rustc_data_structures::ptr_key::PtrKey;
 use rustc::ty;
@@ -17,14 +17,18 @@ use rustc::hir::def_id::{CrateNum, DefId};
 use rustc::hir::def::*;
 use rustc::session::DiagnosticMessageId;
 use rustc::util::nodemap::FxHashSet;
+use rustc::{bug, span_bug};
 
-use syntax::ast::{Ident, Name, NodeId, CRATE_NODE_ID};
+use syntax::ast::{self, Ident, Name, NodeId, CRATE_NODE_ID};
 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
 use syntax::ext::hygiene::Mark;
 use syntax::symbol::keywords;
 use syntax::util::lev_distance::find_best_match_for_name;
+use syntax::{struct_span_err, unwrap_or};
 use syntax_pos::{MultiSpan, Span};
 
+use log::debug;
+
 use std::cell::{Cell, RefCell};
 use std::{mem, ptr};
 
@@ -42,6 +46,8 @@ pub enum ImportDirectiveSubclass<'a> {
         target_bindings: PerNS<Cell<Option<&'a NameBinding<'a>>>>,
         /// `true` for `...::{self [as target]}` imports, `false` otherwise.
         type_ns_only: bool,
+        /// Did this import result from a nested import? ie. `use foo::{bar, baz};`
+        nested: bool,
     },
     GlobImport {
         is_prelude: bool,
@@ -58,26 +64,35 @@ pub enum ImportDirectiveSubclass<'a> {
 /// One import directive.
 #[derive(Debug,Clone)]
 crate struct ImportDirective<'a> {
-    /// The id of the `extern crate`, `UseTree` etc that imported this `ImportDirective`.
+    /// The ID of the `extern crate`, `UseTree` etc that imported this `ImportDirective`.
     ///
     /// In the case where the `ImportDirective` was expanded from a "nested" use tree,
-    /// this id is the id of the leaf tree. For example:
+    /// this id is the ID of the leaf tree. For example:
     ///
     /// ```ignore (pacify the mercilous tidy)
     /// use foo::bar::{a, b}
     /// ```
     ///
-    /// If this is the import directive for `foo::bar::a`, we would have the id of the `UseTree`
+    /// If this is the import directive for `foo::bar::a`, we would have the ID of the `UseTree`
     /// for `a` in this field.
     pub id: NodeId,
 
     /// The `id` of the "root" use-kind -- this is always the same as
     /// `id` except in the case of "nested" use trees, in which case
     /// it will be the `id` of the root use tree. e.g., in the example
-    /// from `id`, this would be the id of the `use foo::bar`
+    /// from `id`, this would be the ID of the `use foo::bar`
     /// `UseTree` node.
     pub root_id: NodeId,
 
+    /// Span of the entire use statement.
+    pub use_span: Span,
+
+    /// Span of the entire use statement with attributes.
+    pub use_span_with_attributes: Span,
+
+    /// Did the use statement have any attributes?
+    pub has_attributes: bool,
+
     /// Span of this use tree.
     pub span: Span,
 
@@ -98,6 +113,13 @@ impl<'a> ImportDirective<'a> {
         match self.subclass { ImportDirectiveSubclass::GlobImport { .. } => true, _ => false }
     }
 
+    pub fn is_nested(&self) -> bool {
+        match self.subclass {
+            ImportDirectiveSubclass::SingleImport { nested, .. } => nested,
+            _ => false
+        }
+    }
+
     crate fn crate_lint(&self) -> CrateLint {
         CrateLint::UsePath { root_id: self.root_id, root_span: self.root_span }
     }
@@ -390,6 +412,7 @@ impl<'a> Resolver<'a> {
                                 subclass: ImportDirectiveSubclass<'a>,
                                 span: Span,
                                 id: NodeId,
+                                item: &ast::Item,
                                 root_span: Span,
                                 root_id: NodeId,
                                 vis: ty::Visibility,
@@ -402,6 +425,9 @@ impl<'a> Resolver<'a> {
             subclass,
             span,
             id,
+            use_span: item.span,
+            use_span_with_attributes: item.span_with_attributes(),
+            has_attributes: !item.attrs.is_empty(),
             root_span,
             root_id,
             vis: Cell::new(vis),
@@ -537,11 +563,8 @@ impl<'a> Resolver<'a> {
                  primary_binding: &'a NameBinding<'a>, secondary_binding: &'a NameBinding<'a>)
                  -> &'a NameBinding<'a> {
         self.arenas.alloc_name_binding(NameBinding {
-            kind: primary_binding.kind.clone(),
             ambiguity: Some((secondary_binding, kind)),
-            vis: primary_binding.vis,
-            span: primary_binding.span,
-            expansion: primary_binding.expansion,
+            ..primary_binding.clone()
         })
     }
 
@@ -604,14 +627,14 @@ pub struct ImportResolver<'a, 'b: 'a> {
     pub resolver: &'a mut Resolver<'b>,
 }
 
-impl<'a, 'b: 'a> ::std::ops::Deref for ImportResolver<'a, 'b> {
+impl<'a, 'b: 'a> std::ops::Deref for ImportResolver<'a, 'b> {
     type Target = Resolver<'b>;
     fn deref(&self) -> &Resolver<'b> {
         self.resolver
     }
 }
 
-impl<'a, 'b: 'a> ::std::ops::DerefMut for ImportResolver<'a, 'b> {
+impl<'a, 'b: 'a> std::ops::DerefMut for ImportResolver<'a, 'b> {
     fn deref_mut(&mut self) -> &mut Resolver<'b> {
         self.resolver
     }
@@ -787,7 +810,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         let (source, target, source_bindings, target_bindings, type_ns_only) =
                 match directive.subclass {
             SingleImport { source, target, ref source_bindings,
-                           ref target_bindings, type_ns_only } =>
+                           ref target_bindings, type_ns_only, .. } =>
                 (source, target, source_bindings, target_bindings, type_ns_only),
             GlobImport { .. } => {
                 self.resolve_glob_import(directive);
@@ -908,7 +931,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
         let (ident, target, source_bindings, target_bindings, type_ns_only) =
                 match directive.subclass {
             SingleImport { source, target, ref source_bindings,
-                           ref target_bindings, type_ns_only } =>
+                           ref target_bindings, type_ns_only, .. } =>
                 (source, target, source_bindings, target_bindings, type_ns_only),
             GlobImport { is_prelude, ref max_vis } => {
                 if directive.module_path.len() <= 1 {
@@ -1297,7 +1320,7 @@ impl<'a, 'b:'a> ImportResolver<'a, 'b> {
 }
 
 fn import_path_to_string(names: &[Ident],
-                         subclass: &ImportDirectiveSubclass,
+                         subclass: &ImportDirectiveSubclass<'_>,
                          span: Span) -> String {
     let pos = names.iter()
         .position(|p| span == p.span && p.name != keywords::PathRoot.name());
@@ -1317,7 +1340,7 @@ fn import_path_to_string(names: &[Ident],
     }
 }
 
-fn import_directive_subclass_to_string(subclass: &ImportDirectiveSubclass) -> String {
+fn import_directive_subclass_to_string(subclass: &ImportDirectiveSubclass<'_>) -> String {
     match *subclass {
         SingleImport { source, .. } => source.to_string(),
         GlobImport { .. } => "*".to_string(),
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index e47f89c64ff07..8bb2e722b5794 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_save_analysis"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_save_analysis"
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index 05156fb51f9da..187ebf0bc4304 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -1,9 +1,9 @@
 //! Write the output of rustc's analysis to an implementor of Dump.
 //!
 //! Dumping the analysis is implemented by walking the AST and getting a bunch of
-//! info out from all over the place. We use Def IDs to identify objects. The
+//! info out from all over the place. We use `DefId`s to identify objects. The
 //! tricky part is getting syntactic (span, source text) and semantic (reference
-//! Def IDs) information for parts of expressions which the compiler has discarded.
+//! `DefId`s) information for parts of expressions which the compiler has discarded.
 //! E.g., in a path `foo::bar::baz`, the compiler only keeps a span for the whole
 //! path and a reference to `baz`, but we want spans and references for all three
 //! idents.
@@ -16,6 +16,7 @@
 use rustc::hir::def::Def as HirDef;
 use rustc::hir::def_id::DefId;
 use rustc::session::config::Input;
+use rustc::span_bug;
 use rustc::ty::{self, TyCtxt};
 use rustc_data_structures::fx::FxHashSet;
 
@@ -32,16 +33,20 @@ use syntax::print::pprust::{
 };
 use syntax::ptr::P;
 use syntax::source_map::{Spanned, DUMMY_SP, respan};
+use syntax::walk_list;
 use syntax_pos::*;
 
-use {escape, generated_code, lower_attributes, PathCollector, SaveContext};
-use json_dumper::{Access, DumpOutput, JsonDumper};
-use span_utils::SpanUtils;
-use sig;
+use crate::{escape, generated_code, id_from_def_id, id_from_node_id, lower_attributes,
+            PathCollector, SaveContext};
+use crate::json_dumper::{Access, DumpOutput, JsonDumper};
+use crate::span_utils::SpanUtils;
+use crate::sig;
 
 use rls_data::{CompilationOptions, CratePreludeData, Def, DefKind, GlobalCrateId, Import,
                ImportKind, Ref, RefKind, Relation, RelationKind, SpanData};
 
+use log::{debug, error};
+
 macro_rules! down_cast_data {
     ($id:ident, $kind:ident, $sp:expr) => {
         let $id = if let super::Data::$kind(data) = $id {
@@ -68,7 +73,7 @@ macro_rules! access_from {
     };
 }
 
-pub struct DumpVisitor<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> {
+pub struct DumpVisitor<'l, 'tcx: 'l, 'll, O: DumpOutput> {
     save_ctxt: SaveContext<'l, 'tcx>,
     tcx: TyCtxt<'l, 'tcx, 'tcx>,
     dumper: &'ll mut JsonDumper<O>,
@@ -240,12 +245,12 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
 
             for (id, ident, ..) in collector.collected_idents {
                 let hir_id = self.tcx.hir().node_to_hir_id(id);
-                let typ = match self.save_ctxt.tables.node_id_to_type_opt(hir_id) {
+                let typ = match self.save_ctxt.tables.node_type_opt(hir_id) {
                     Some(s) => s.to_string(),
                     None => continue,
                 };
                 if !self.span.filter_generated(ident.span) {
-                    let id = ::id_from_node_id(id, &self.save_ctxt);
+                    let id = id_from_node_id(id, &self.save_ctxt);
                     let span = self.span_from_span(ident.span);
 
                     self.dumper.dump_def(
@@ -286,7 +291,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         debug!("process_method: {}:{}", id, ident);
 
         if let Some(mut method_data) = self.save_ctxt.get_method_data(id, ident, span) {
-            let sig_str = ::make_signature(&sig.decl, &generics);
+            let sig_str = crate::make_signature(&sig.decl, &generics);
             if body.is_some() {
                 self.nest_tables(
                     id,
@@ -339,7 +344,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     // Append $id to name to make sure each one is unique.
                     let qualname = format!("{}::{}${}", prefix, name, id);
                     if !self.span.filter_generated(param_ss) {
-                        let id = ::id_from_node_id(param.id, &self.save_ctxt);
+                        let id = id_from_node_id(param.id, &self.save_ctxt);
                         let span = self.span_from_span(param_ss);
 
                         self.dumper.dump_def(
@@ -364,6 +369,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                         );
                     }
                 }
+                ast::GenericParamKind::Const { .. } => {}
             }
         }
         self.visit_generics(generics);
@@ -433,12 +439,12 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                 &access_from!(self.save_ctxt, vis, id),
                 Def {
                     kind: DefKind::Const,
-                    id: ::id_from_node_id(id, &self.save_ctxt),
+                    id: id_from_node_id(id, &self.save_ctxt),
                     span,
                     name: ident.name.to_string(),
                     qualname,
                     value: ty_to_string(&typ),
-                    parent: Some(::id_from_def_id(parent_id)),
+                    parent: Some(id_from_def_id(parent_id)),
                     children: vec![],
                     decl_id: None,
                     docs: self.save_ctxt.docs_for_attrs(attrs),
@@ -495,7 +501,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     value,
                     fields
                         .iter()
-                        .map(|f| ::id_from_node_id(f.id, &self.save_ctxt))
+                        .map(|f| id_from_node_id(f.id, &self.save_ctxt))
                         .collect(),
                 )
             }
@@ -508,7 +514,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                 &access_from!(self.save_ctxt, item),
                 Def {
                     kind,
-                    id: ::id_from_node_id(item.id, &self.save_ctxt),
+                    id: id_from_node_id(item.id, &self.save_ctxt),
                     span,
                     name,
                     qualname: qualname.clone(),
@@ -564,8 +570,8 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     let value = format!("{}::{} {{ {} }}", enum_data.name, name, fields_str);
                     if !self.span.filter_generated(name_span) {
                         let span = self.span_from_span(name_span);
-                        let id = ::id_from_node_id(variant.node.data.id(), &self.save_ctxt);
-                        let parent = Some(::id_from_node_id(item.id, &self.save_ctxt));
+                        let id = id_from_node_id(variant.node.data.id(), &self.save_ctxt);
+                        let parent = Some(id_from_node_id(item.id, &self.save_ctxt));
 
                         self.dumper.dump_def(
                             &access,
@@ -602,8 +608,8 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     }
                     if !self.span.filter_generated(name_span) {
                         let span = self.span_from_span(name_span);
-                        let id = ::id_from_node_id(variant.node.data.id(), &self.save_ctxt);
-                        let parent = Some(::id_from_node_id(item.id, &self.save_ctxt));
+                        let id = id_from_node_id(variant.node.data.id(), &self.save_ctxt);
+                        let parent = Some(id_from_node_id(item.id, &self.save_ctxt));
 
                         self.dumper.dump_def(
                             &access,
@@ -686,11 +692,11 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
             val.push_str(&bounds_to_string(trait_refs));
         }
         if !self.span.filter_generated(item.ident.span) {
-            let id = ::id_from_node_id(item.id, &self.save_ctxt);
+            let id = id_from_node_id(item.id, &self.save_ctxt);
             let span = self.span_from_span(item.ident.span);
             let children = methods
                 .iter()
-                .map(|i| ::id_from_node_id(i.id, &self.save_ctxt))
+                .map(|i| id_from_node_id(i.id, &self.save_ctxt))
                 .collect();
             self.dumper.dump_def(
                 &access_from!(self.save_ctxt, item),
@@ -726,14 +732,14 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     self.dumper.dump_ref(Ref {
                         kind: RefKind::Type,
                         span: span.clone(),
-                        ref_id: ::id_from_def_id(id),
+                        ref_id: id_from_def_id(id),
                     });
 
                     self.dumper.dump_relation(Relation {
                         kind: RelationKind::SuperTrait,
                         span,
-                        from: ::id_from_def_id(id),
-                        to: ::id_from_node_id(item.id, &self.save_ctxt),
+                        from: id_from_def_id(id),
+                        to: id_from_node_id(item.id, &self.save_ctxt),
                     });
                 }
             }
@@ -857,7 +863,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
             PatKind::Struct(ref _path, ref fields, _) => {
                 // FIXME do something with _path?
                 let hir_id = self.tcx.hir().node_to_hir_id(p.id);
-                let adt = match self.save_ctxt.tables.node_id_to_type_opt(hir_id) {
+                let adt = match self.save_ctxt.tables.node_type_opt(hir_id) {
                     Some(ty) => ty.ty_adt_def().unwrap(),
                     None => {
                         visit::walk_pat(self, p);
@@ -873,7 +879,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                             self.dumper.dump_ref(Ref {
                                 kind: RefKind::Variable,
                                 span,
-                                ref_id: ::id_from_def_id(variant.fields[index].did),
+                                ref_id: id_from_def_id(variant.fields[index].did),
                             });
                         }
                     }
@@ -904,7 +910,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                     let hir_id = self.tcx.hir().node_to_hir_id(id);
                     let typ = self.save_ctxt
                         .tables
-                        .node_id_to_type_opt(hir_id)
+                        .node_type_opt(hir_id)
                         .map(|t| t.to_string())
                         .unwrap_or_default();
                     value.push_str(": ");
@@ -912,7 +918,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
 
                     if !self.span.filter_generated(ident.span) {
                         let qualname = format!("{}${}", ident.to_string(), id);
-                        let id = ::id_from_node_id(id, &self.save_ctxt);
+                        let id = id_from_node_id(id, &self.save_ctxt);
                         let span = self.span_from_span(ident.span);
 
                         self.dumper.dump_def(
@@ -973,7 +979,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                 _ => String::new(),
             };
             let hir_id = self.tcx.hir().node_to_hir_id(id);
-            let typ = match self.save_ctxt.tables.node_id_to_type_opt(hir_id) {
+            let typ = match self.save_ctxt.tables.node_type_opt(hir_id) {
                 Some(typ) => {
                     let typ = typ.to_string();
                     if !value.is_empty() {
@@ -988,7 +994,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
             // Rust uses the id of the pattern for var lookups, so we'll use it too.
             if !self.span.filter_generated(ident.span) {
                 let qualname = format!("{}${}", ident.to_string(), id);
-                let id = ::id_from_node_id(id, &self.save_ctxt);
+                let id = id_from_node_id(id, &self.save_ctxt);
                 let span = self.span_from_span(ident.span);
 
                 self.dumper.dump_def(
@@ -1015,7 +1021,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         }
     }
 
-    /// Extract macro use and definition information from the AST node defined
+    /// Extracts macro use and definition information from the AST node defined
     /// by the given NodeId, using the expansion information from the node's
     /// span.
     ///
@@ -1091,7 +1097,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
 
                 if !self.span.filter_generated(trait_item.ident.span) {
                     let span = self.span_from_span(trait_item.ident.span);
-                    let id = ::id_from_node_id(trait_item.id, &self.save_ctxt);
+                    let id = id_from_node_id(trait_item.id, &self.save_ctxt);
 
                     self.dumper.dump_def(
                         &Access {
@@ -1105,7 +1111,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                             name,
                             qualname,
                             value: self.span.snippet(trait_item.span),
-                            parent: Some(::id_from_def_id(trait_id)),
+                            parent: Some(id_from_def_id(trait_id)),
                             children: vec![],
                             decl_id: None,
                             docs: self.save_ctxt.docs_for_attrs(&trait_item.attrs),
@@ -1178,7 +1184,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
     ///
     /// A use tree is an import that may contain nested braces (RFC 2128). The `use_tree` parameter
     /// is the current use tree under scrutiny, while `id` and `prefix` are its corresponding node
-    /// id and path. `root_item` is the topmost use tree in the hierarchy.
+    /// ID and path. `root_item` is the topmost use tree in the hierarchy.
     ///
     /// If `use_tree` is a simple or glob import, it is dumped into the analysis data. Otherwise,
     /// each child use tree is dumped recursively.
@@ -1196,7 +1202,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
         // The parent def id of a given use tree is always the enclosing item.
         let parent = self.save_ctxt.tcx.hir().opt_local_def_id(id)
             .and_then(|id| self.save_ctxt.tcx.parent_def_id(id))
-            .map(::id_from_def_id);
+            .map(id_from_def_id);
 
         match use_tree.kind {
             ast::UseTreeKind::Simple(alias, ..) => {
@@ -1212,7 +1218,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
 
                 let sub_span = path.segments.last().unwrap().ident.span;
                 if !self.span.filter_generated(sub_span) {
-                    let ref_id = self.lookup_def_id(id).map(|id| ::id_from_def_id(id));
+                    let ref_id = self.lookup_def_id(id).map(|id| id_from_def_id(id));
                     let alias_span = alias.map(|i| self.span_from_span(i.span));
                     let span = self.span_from_span(sub_span);
                     self.dumper.import(&access, Import {
@@ -1238,12 +1244,9 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
                 };
 
                 // Make a comma-separated list of names of imported modules.
-                let glob_map = &self.save_ctxt.analysis.glob_map;
-                let names = if glob_map.contains_key(&id) {
-                    glob_map.get(&id).unwrap().iter().map(|n| n.to_string()).collect()
-                } else {
-                    Vec::new()
-                };
+                let def_id = self.tcx.hir().local_def_id(id);
+                let names = self.tcx.names_imported_by_glob_use(def_id);
+                let names: Vec<_> = names.iter().map(|n| n.to_string()).collect();
 
                 // Otherwise it's a span with wrong macro expansion info, which
                 // we don't want to track anyway, since it's probably macro-internal `use`
@@ -1301,10 +1304,10 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
 
         let cm = self.tcx.sess.source_map();
         let filename = cm.span_to_filename(span);
-        let data_id = ::id_from_node_id(id, &self.save_ctxt);
+        let data_id = id_from_node_id(id, &self.save_ctxt);
         let children = m.items
             .iter()
-            .map(|i| ::id_from_node_id(i.id, &self.save_ctxt))
+            .map(|i| id_from_node_id(i.id, &self.save_ctxt))
             .collect();
         let span = self.span_from_span(span);
 
@@ -1348,7 +1351,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
                     let span = self.span_from_span(name_span);
                     let parent = self.save_ctxt.tcx.hir().opt_local_def_id(item.id)
                         .and_then(|id| self.save_ctxt.tcx.parent_def_id(id))
-                        .map(::id_from_def_id);
+                        .map(id_from_def_id);
                     self.dumper.import(
                         &Access {
                             public: false,
@@ -1390,7 +1393,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
                 let value = ty_to_string(&ty);
                 if !self.span.filter_generated(item.ident.span) {
                     let span = self.span_from_span(item.ident.span);
-                    let id = ::id_from_node_id(item.id, &self.save_ctxt);
+                    let id = id_from_node_id(item.id, &self.save_ctxt);
 
                     self.dumper.dump_def(
                         &access_from!(self.save_ctxt, item),
@@ -1420,7 +1423,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
                 let value = String::new();
                 if !self.span.filter_generated(item.ident.span) {
                     let span = self.span_from_span(item.ident.span);
-                    let id = ::id_from_node_id(item.id, &self.save_ctxt);
+                    let id = id_from_node_id(item.id, &self.save_ctxt);
 
                     self.dumper.dump_def(
                         &access_from!(self.save_ctxt, item),
@@ -1450,9 +1453,16 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
 
     fn visit_generics(&mut self, generics: &'l ast::Generics) {
         for param in &generics.params {
-            if let ast::GenericParamKind::Type { ref default, .. } = param.kind {
-                self.process_bounds(&param.bounds);
-                if let Some(ref ty) = default {
+            match param.kind {
+                ast::GenericParamKind::Lifetime { .. } => {}
+                ast::GenericParamKind::Type { ref default, .. } => {
+                    self.process_bounds(&param.bounds);
+                    if let Some(ref ty) = default {
+                        self.visit_ty(&ty);
+                    }
+                }
+                ast::GenericParamKind::Const { ref ty } => {
+                    self.process_bounds(&param.bounds);
                     self.visit_ty(&ty);
                 }
             }
@@ -1479,7 +1489,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> Visitor<'l> for DumpVisitor<'l, 'tc
                     self.dumper.dump_ref(Ref {
                         kind: RefKind::Type,
                         span,
-                        ref_id: ::id_from_def_id(id),
+                        ref_id: id_from_def_id(id),
                     });
                 }
 
diff --git a/src/librustc_save_analysis/json_dumper.rs b/src/librustc_save_analysis/json_dumper.rs
index 3627c5577a626..1840cf652e1d5 100644
--- a/src/librustc_save_analysis/json_dumper.rs
+++ b/src/librustc_save_analysis/json_dumper.rs
@@ -7,6 +7,8 @@ use rls_data::{self, Analysis, CompilationOptions, CratePreludeData, Def, DefKin
                MacroRef, Ref, RefKind, Relation};
 use rls_span::{Column, Row};
 
+use log::error;
+
 #[derive(Debug)]
 pub struct Access {
     pub reachable: bool,
@@ -23,7 +25,7 @@ pub trait DumpOutput {
     fn dump(&mut self, result: &Analysis);
 }
 
-pub struct WriteOutput<'b, W: Write + 'b> {
+pub struct WriteOutput<'b, W: Write> {
     output: &'b mut W,
 }
 
diff --git a/src/librustc_save_analysis/lib.rs b/src/librustc_save_analysis/lib.rs
index 4d55004a055f0..8ab9a8e8dda86 100644
--- a/src/librustc_save_analysis/lib.rs
+++ b/src/librustc_save_analysis/lib.rs
@@ -1,29 +1,11 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(custom_attribute)]
 #![feature(nll)]
+#![deny(rust_2018_idioms)]
 #![allow(unused_attributes)]
 
 #![recursion_limit="256"]
 
-#[macro_use]
-extern crate rustc;
-
-#[macro_use]
-extern crate log;
-extern crate rustc_data_structures;
-extern crate rustc_codegen_utils;
-extern crate rustc_serialize;
-extern crate rustc_target;
-extern crate rustc_typeck;
-#[macro_use]
-extern crate syntax;
-extern crate syntax_pos;
-
-extern crate rls_data;
-extern crate rls_span;
-
 
 mod json_dumper;
 mod dump_visitor;
@@ -39,6 +21,7 @@ use rustc::middle::privacy::AccessLevels;
 use rustc::middle::cstore::ExternCrate;
 use rustc::session::config::{CrateType, Input, OutputType};
 use rustc::ty::{self, TyCtxt};
+use rustc::{bug, span_bug};
 use rustc_typeck::hir_ty_to_ty;
 use rustc_codegen_utils::link::{filename_for_metadata, out_filename};
 use rustc_data_structures::sync::Lrc;
@@ -66,12 +49,13 @@ use rls_data::{Def, DefKind, ExternalCrateData, GlobalCrateId, MacroRef, Ref, Re
                RelationKind, SpanData, Impl, ImplKind};
 use rls_data::config::Config;
 
+use log::{debug, error, info};
+
 
 pub struct SaveContext<'l, 'tcx: 'l> {
     tcx: TyCtxt<'l, 'tcx, 'tcx>,
     tables: &'l ty::TypeckTables<'tcx>,
     access_levels: &'l AccessLevels,
-    analysis: &'l ty::CrateAnalysis,
     span_utils: SpanUtils<'tcx>,
     config: Config,
     impl_counter: Cell<u32>,
@@ -173,7 +157,7 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
             ast::ForeignItemKind::Static(ref ty, _) => {
                 filter!(self.span_utils, item.ident.span);
 
-                let id = ::id_from_node_id(item.id, self);
+                let id = id_from_node_id(item.id, self);
                 let span = self.span_from_span(item.ident.span);
 
                 Some(Data::DefData(Def {
@@ -630,11 +614,16 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
                     Some(def) if def != HirDef::Err => def,
                     _ => self.get_path_def(self.tcx.hir().get_parent_node(id)),
                 }
-            },
+            }
+
             Node::Expr(&hir::Expr {
                 node: hir::ExprKind::Struct(ref qpath, ..),
                 ..
-            }) |
+            }) => {
+                let hir_id = self.tcx.hir().node_to_hir_id(id);
+                self.tables.qpath_def(qpath, hir_id)
+            }
+
             Node::Expr(&hir::Expr {
                 node: hir::ExprKind::Path(ref qpath),
                 ..
@@ -763,6 +752,13 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
                     ref_id: id_from_def_id(def_id),
                 })
             }
+            HirDef::ConstParam(def_id) => {
+                Some(Ref {
+                    kind: RefKind::Variable,
+                    span,
+                    ref_id: id_from_def_id(def_id),
+                })
+            }
             HirDef::StructCtor(def_id, _) => {
                 // This is a reference to a tuple struct where the def_id points
                 // to an invisible constructor function. That is not a very useful
@@ -835,7 +831,7 @@ impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
     /// Attempt to return MacroRef for any AST node.
     ///
     /// For a given piece of AST defined by the supplied Span and NodeId,
-    /// returns None if the node is not macro-generated or the span is malformed,
+    /// returns `None` if the node is not macro-generated or the span is malformed,
     /// else uses the expansion callsite and callee to return some MacroRef.
     pub fn get_macro_use_data(&self, span: Span) -> Option<MacroRef> {
         if !generated_code(span) {
@@ -1030,7 +1026,7 @@ impl<'a> DumpHandler<'a> {
         }
     }
 
-    fn output_file(&self, ctx: &SaveContext) -> File {
+    fn output_file(&self, ctx: &SaveContext<'_, '_>) -> File {
         let sess = &ctx.tcx.sess;
         let file_name = match ctx.config.output_file {
             Some(ref s) => PathBuf::from(s),
@@ -1120,7 +1116,6 @@ impl<'b> SaveHandler for CallbackHandler<'b> {
 pub fn process_crate<'l, 'tcx, H: SaveHandler>(
     tcx: TyCtxt<'l, 'tcx, 'tcx>,
     krate: &ast::Crate,
-    analysis: &'l ty::CrateAnalysis,
     cratename: &str,
     input: &'l Input,
     config: Option<Config>,
@@ -1139,7 +1134,6 @@ pub fn process_crate<'l, 'tcx, H: SaveHandler>(
         let save_ctxt = SaveContext {
             tcx,
             tables: &ty::TypeckTables::empty(None),
-            analysis,
             access_levels: &access_levels,
             span_utils: SpanUtils::new(&tcx.sess),
             config: find_config(config),
@@ -1183,7 +1177,7 @@ fn id_from_def_id(id: DefId) -> rls_data::Id {
     }
 }
 
-fn id_from_node_id(id: NodeId, scx: &SaveContext) -> rls_data::Id {
+fn id_from_node_id(id: NodeId, scx: &SaveContext<'_, '_>) -> rls_data::Id {
     let def_id = scx.tcx.hir().opt_local_def_id(id);
     def_id.map(|id| id_from_def_id(id)).unwrap_or_else(|| {
         // Create a *fake* `DefId` out of a `NodeId` by subtracting the `NodeId`
@@ -1203,7 +1197,7 @@ fn null_id() -> rls_data::Id {
     }
 }
 
-fn lower_attributes(attrs: Vec<Attribute>, scx: &SaveContext) -> Vec<rls_data::Attribute> {
+fn lower_attributes(attrs: Vec<Attribute>, scx: &SaveContext<'_, '_>) -> Vec<rls_data::Attribute> {
     attrs.into_iter()
     // Only retain real attributes. Doc comments are lowered separately.
     .filter(|attr| attr.path != "doc")
diff --git a/src/librustc_save_analysis/sig.rs b/src/librustc_save_analysis/sig.rs
index 7d4c0d0f9f56f..50a335bf90877 100644
--- a/src/librustc_save_analysis/sig.rs
+++ b/src/librustc_save_analysis/sig.rs
@@ -25,7 +25,7 @@
 //
 // FIXME where clauses need implementing, defs/refs in generics are mostly missing.
 
-use {id_from_def_id, id_from_node_id, SaveContext};
+use crate::{id_from_def_id, id_from_node_id, SaveContext};
 
 use rls_data::{SigElement, Signature};
 
@@ -34,14 +34,17 @@ use syntax::ast::{self, NodeId};
 use syntax::print::pprust;
 
 
-pub fn item_signature(item: &ast::Item, scx: &SaveContext) -> Option<Signature> {
+pub fn item_signature(item: &ast::Item, scx: &SaveContext<'_, '_>) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
     }
     item.make(0, None, scx).ok()
 }
 
-pub fn foreign_item_signature(item: &ast::ForeignItem, scx: &SaveContext) -> Option<Signature> {
+pub fn foreign_item_signature(
+    item: &ast::ForeignItem,
+    scx: &SaveContext<'_, '_>
+) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
     }
@@ -50,7 +53,7 @@ pub fn foreign_item_signature(item: &ast::ForeignItem, scx: &SaveContext) -> Opt
 
 /// Signature for a struct or tuple field declaration.
 /// Does not include a trailing comma.
-pub fn field_signature(field: &ast::StructField, scx: &SaveContext) -> Option<Signature> {
+pub fn field_signature(field: &ast::StructField, scx: &SaveContext<'_, '_>) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
     }
@@ -58,7 +61,7 @@ pub fn field_signature(field: &ast::StructField, scx: &SaveContext) -> Option<Si
 }
 
 /// Does not include a trailing comma.
-pub fn variant_signature(variant: &ast::Variant, scx: &SaveContext) -> Option<Signature> {
+pub fn variant_signature(variant: &ast::Variant, scx: &SaveContext<'_, '_>) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
     }
@@ -70,7 +73,7 @@ pub fn method_signature(
     ident: ast::Ident,
     generics: &ast::Generics,
     m: &ast::MethodSig,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
@@ -83,7 +86,7 @@ pub fn assoc_const_signature(
     ident: ast::Name,
     ty: &ast::Ty,
     default: Option<&ast::Expr>,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
@@ -96,7 +99,7 @@ pub fn assoc_type_signature(
     ident: ast::Ident,
     bounds: Option<&ast::GenericBounds>,
     default: Option<&ast::Ty>,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Option<Signature> {
     if !scx.config.signatures {
         return None;
@@ -104,10 +107,10 @@ pub fn assoc_type_signature(
     make_assoc_type_signature(id, ident, bounds, default, scx).ok()
 }
 
-type Result = ::std::result::Result<Signature, &'static str>;
+type Result = std::result::Result<Signature, &'static str>;
 
 trait Sig {
-    fn make(&self, offset: usize, id: Option<NodeId>, scx: &SaveContext) -> Result;
+    fn make(&self, offset: usize, id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result;
 }
 
 fn extend_sig(
@@ -155,7 +158,7 @@ fn text_sig(text: String) -> Signature {
 }
 
 impl Sig for ast::Ty {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let id = Some(self.id);
         match self.node {
             ast::TyKind::Slice(ref ty) => {
@@ -227,7 +230,7 @@ impl Sig for ast::Ty {
                 if f.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if f.abi != ::rustc_target::spec::abi::Abi::Rust {
+                if f.abi != rustc_target::spec::abi::Abi::Rust {
                     text.push_str("extern");
                     text.push_str(&f.abi.to_string());
                     text.push(' ');
@@ -317,7 +320,7 @@ impl Sig for ast::Ty {
 }
 
 impl Sig for ast::Item {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let id = Some(self.id);
 
         match self.node {
@@ -381,7 +384,7 @@ impl Sig for ast::Item {
                 if header.unsafety == ast::Unsafety::Unsafe {
                     text.push_str("unsafe ");
                 }
-                if header.abi != ::rustc_target::spec::abi::Abi::Rust {
+                if header.abi != rustc_target::spec::abi::Abi::Rust {
                     text.push_str("extern");
                     text.push_str(&header.abi.to_string());
                     text.push(' ');
@@ -571,7 +574,7 @@ impl Sig for ast::Item {
 }
 
 impl Sig for ast::Path {
-    fn make(&self, offset: usize, id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let def = scx.get_path_def(id.ok_or("Missing id for Path")?);
 
         let (name, start, end) = match def {
@@ -613,7 +616,7 @@ impl Sig for ast::Path {
 
 // This does not cover the where clause, which must be processed separately.
 impl Sig for ast::Generics {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         if self.params.is_empty() {
             return Ok(text_sig(String::new()));
         }
@@ -622,12 +625,20 @@ impl Sig for ast::Generics {
 
         let mut defs = Vec::with_capacity(self.params.len());
         for param in &self.params {
-            let mut param_text = param.ident.to_string();
+            let mut param_text = String::new();
+            if let ast::GenericParamKind::Const { .. } = param.kind {
+                param_text.push_str("const ");
+            }
+            param_text.push_str(&param.ident.as_str());
             defs.push(SigElement {
                 id: id_from_node_id(param.id, scx),
                 start: offset + text.len(),
-                end: offset + text.len() + param_text.len(),
+                end: offset + text.len() + param_text.as_str().len(),
             });
+            if let ast::GenericParamKind::Const { ref ty } = param.kind {
+                param_text.push_str(": ");
+                param_text.push_str(&pprust::ty_to_string(&ty));
+            }
             if !param.bounds.is_empty() {
                 param_text.push_str(": ");
                 match param.kind {
@@ -646,6 +657,9 @@ impl Sig for ast::Generics {
                         param_text.push_str(&pprust::bounds_to_string(&param.bounds));
                         // FIXME descend properly into bounds.
                     }
+                    ast::GenericParamKind::Const { .. } => {
+                        // Const generics cannot contain bounds.
+                    }
                 }
             }
             text.push_str(&param_text);
@@ -662,7 +676,7 @@ impl Sig for ast::Generics {
 }
 
 impl Sig for ast::StructField {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let mut text = String::new();
         let mut defs = None;
         if let Some(ident) = self.ident {
@@ -685,7 +699,7 @@ impl Sig for ast::StructField {
 
 
 impl Sig for ast::Variant_ {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let mut text = self.ident.to_string();
         match self.data {
             ast::VariantData::Struct(ref fields, id) => {
@@ -743,7 +757,7 @@ impl Sig for ast::Variant_ {
 }
 
 impl Sig for ast::ForeignItem {
-    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext) -> Result {
+    fn make(&self, offset: usize, _parent_id: Option<NodeId>, scx: &SaveContext<'_, '_>) -> Result {
         let id = Some(self.id);
         match self.node {
             ast::ForeignItemKind::Fn(ref decl, ref generics) => {
@@ -827,7 +841,7 @@ fn name_and_generics(
     generics: &ast::Generics,
     id: NodeId,
     name: ast::Ident,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Result {
     let name = name.to_string();
     let def = SigElement {
@@ -848,7 +862,7 @@ fn make_assoc_type_signature(
     ident: ast::Ident,
     bounds: Option<&ast::GenericBounds>,
     default: Option<&ast::Ty>,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Result {
     let mut text = "type ".to_owned();
     let name = ident.to_string();
@@ -882,7 +896,7 @@ fn make_assoc_const_signature(
     ident: ast::Name,
     ty: &ast::Ty,
     default: Option<&ast::Expr>,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Result {
     let mut text = "const ".to_owned();
     let name = ident.to_string();
@@ -915,7 +929,7 @@ fn make_method_signature(
     ident: ast::Ident,
     generics: &ast::Generics,
     m: &ast::MethodSig,
-    scx: &SaveContext,
+    scx: &SaveContext<'_, '_>,
 ) -> Result {
     // FIXME code dup with function signature
     let mut text = String::new();
@@ -928,7 +942,7 @@ fn make_method_signature(
     if m.header.unsafety == ast::Unsafety::Unsafe {
         text.push_str("unsafe ");
     }
-    if m.header.abi != ::rustc_target::spec::abi::Abi::Rust {
+    if m.header.abi != rustc_target::spec::abi::Abi::Rust {
         text.push_str("extern");
         text.push_str(&m.header.abi.to_string());
         text.push(' ');
diff --git a/src/librustc_save_analysis/span_utils.rs b/src/librustc_save_analysis/span_utils.rs
index 88c6012f71f69..e2c93b6d33158 100644
--- a/src/librustc_save_analysis/span_utils.rs
+++ b/src/librustc_save_analysis/span_utils.rs
@@ -1,6 +1,6 @@
 use rustc::session::Session;
 
-use generated_code;
+use crate::generated_code;
 
 use std::cell::Cell;
 
diff --git a/src/librustc_target/Cargo.toml b/src/librustc_target/Cargo.toml
index dfdd7f0ae58e5..ecea15a992250 100644
--- a/src/librustc_target/Cargo.toml
+++ b/src/librustc_target/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_target"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_target"
diff --git a/src/librustc_target/abi/call/aarch64.rs b/src/librustc_target/abi/call/aarch64.rs
index 121f80c75b9ac..f50ec6c2e7e3a 100644
--- a/src/librustc_target/abi/call/aarch64.rs
+++ b/src/librustc_target/abi/call/aarch64.rs
@@ -1,12 +1,12 @@
-use abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
 
 fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgType<'a, Ty>)
                                      -> Option<Uniform>
     where Ty: TyLayoutMethods<'a, C> + Copy,
           C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout
 {
-    arg.layout.homogeneous_aggregate(cx).and_then(|unit| {
+    arg.layout.homogeneous_aggregate(cx).unit().and_then(|unit| {
         let size = arg.layout.size;
 
         // Ensure we have at most four uniquely addressable members.
diff --git a/src/librustc_target/abi/call/amdgpu.rs b/src/librustc_target/abi/call/amdgpu.rs
index ea9d4172cbc23..6bfd1f4387385 100644
--- a/src/librustc_target/abi/call/amdgpu.rs
+++ b/src/librustc_target/abi/call/amdgpu.rs
@@ -1,5 +1,5 @@
-use abi::call::{ArgType, FnType, };
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::abi::call::{ArgType, FnType, };
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
 
 fn classify_ret_ty<'a, Ty, C>(_cx: &C, ret: &mut ArgType<'a, Ty>)
   where Ty: TyLayoutMethods<'a, C> + Copy,
diff --git a/src/librustc_target/abi/call/arm.rs b/src/librustc_target/abi/call/arm.rs
index 2b3588d31bf1f..52d7f3ac3dcbf 100644
--- a/src/librustc_target/abi/call/arm.rs
+++ b/src/librustc_target/abi/call/arm.rs
@@ -1,13 +1,13 @@
-use abi::call::{Conv, FnType, ArgType, Reg, RegKind, Uniform};
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
-use spec::HasTargetSpec;
+use crate::abi::call::{Conv, FnType, ArgType, Reg, RegKind, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::spec::HasTargetSpec;
 
 fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgType<'a, Ty>)
                                      -> Option<Uniform>
     where Ty: TyLayoutMethods<'a, C> + Copy,
           C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout
 {
-    arg.layout.homogeneous_aggregate(cx).and_then(|unit| {
+    arg.layout.homogeneous_aggregate(cx).unit().and_then(|unit| {
         let size = arg.layout.size;
 
         // Ensure we have at most four uniquely addressable members.
diff --git a/src/librustc_target/abi/call/asmjs.rs b/src/librustc_target/abi/call/asmjs.rs
index 32c6634b3d250..92c86372a86f3 100644
--- a/src/librustc_target/abi/call/asmjs.rs
+++ b/src/librustc_target/abi/call/asmjs.rs
@@ -1,5 +1,5 @@
-use abi::call::{FnType, ArgType, Uniform};
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::abi::call::{FnType, ArgType, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
 
 // Data layout: e-p:32:32-i64:64-v128:32:128-n32-S128
 
@@ -11,7 +11,7 @@ fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<'a, Ty>)
           C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout
 {
     if ret.layout.is_aggregate() {
-        if let Some(unit) = ret.layout.homogeneous_aggregate(cx) {
+        if let Some(unit) = ret.layout.homogeneous_aggregate(cx).unit() {
             let size = ret.layout.size;
             if unit.size == size {
                 ret.cast_to(Uniform {
@@ -26,7 +26,7 @@ fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<'a, Ty>)
     }
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     if arg.layout.is_aggregate() {
         arg.make_indirect_byval();
     }
diff --git a/src/librustc_target/abi/call/hexagon.rs b/src/librustc_target/abi/call/hexagon.rs
index d538a8068ac4a..db8c915cdb4bd 100644
--- a/src/librustc_target/abi/call/hexagon.rs
+++ b/src/librustc_target/abi/call/hexagon.rs
@@ -1,8 +1,8 @@
 #![allow(non_upper_case_globals)]
 
-use abi::call::{FnType, ArgType};
+use crate::abi::call::{FnType, ArgType};
 
-fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
+fn classify_ret_ty<Ty>(ret: &mut ArgType<'_, Ty>) {
     if ret.layout.is_aggregate() && ret.layout.size.bits() > 64 {
         ret.make_indirect();
     } else {
@@ -10,7 +10,7 @@ fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
     }
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     if arg.layout.is_aggregate() && arg.layout.size.bits() > 64 {
         arg.make_indirect();
     } else {
@@ -18,7 +18,7 @@ fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
     }
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_,Ty>) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret);
     }
diff --git a/src/librustc_target/abi/call/mips.rs b/src/librustc_target/abi/call/mips.rs
index 2335bfbb5b87b..d496abf8e8b28 100644
--- a/src/librustc_target/abi/call/mips.rs
+++ b/src/librustc_target/abi/call/mips.rs
@@ -1,7 +1,7 @@
-use abi::call::{ArgType, FnType, Reg, Uniform};
-use abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
+use crate::abi::call::{ArgType, FnType, Reg, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
 
-fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     if !ret.layout.is_aggregate() {
@@ -12,7 +12,7 @@ fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
     }
 }
 
-fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let dl = cx.data_layout();
@@ -34,7 +34,7 @@ fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
     *offset = offset.align_to(align) + size.align_to(align);
 }
 
-pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<Ty>)
+pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<'_, Ty>)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let mut offset = Size::ZERO;
diff --git a/src/librustc_target/abi/call/mips64.rs b/src/librustc_target/abi/call/mips64.rs
index 6f3e6494a4ae8..5ba05c6bcde37 100644
--- a/src/librustc_target/abi/call/mips64.rs
+++ b/src/librustc_target/abi/call/mips64.rs
@@ -1,7 +1,7 @@
-use abi::call::{ArgAttribute, ArgType, CastTarget, FnType, PassMode, Reg, RegKind, Uniform};
-use abi::{self, HasDataLayout, LayoutOf, Size, TyLayout, TyLayoutMethods};
+use crate::abi::call::{ArgAttribute, ArgType, CastTarget, FnType, PassMode, Reg, RegKind, Uniform};
+use crate::abi::{self, HasDataLayout, LayoutOf, Size, TyLayout, TyLayoutMethods};
 
-fn extend_integer_width_mips<Ty>(arg: &mut ArgType<Ty>, bits: u64) {
+fn extend_integer_width_mips<Ty>(arg: &mut ArgType<'_, Ty>, bits: u64) {
     // Always sign extend u32 values on 64-bit mips
     if let abi::Abi::Scalar(ref scalar) = arg.layout.abi {
         if let abi::Int(i, signed) = scalar.value {
diff --git a/src/librustc_target/abi/call/mod.rs b/src/librustc_target/abi/call/mod.rs
index 37bf6e68247d2..411eb192d902b 100644
--- a/src/librustc_target/abi/call/mod.rs
+++ b/src/librustc_target/abi/call/mod.rs
@@ -1,6 +1,6 @@
-use abi::{self, Abi, Align, FieldPlacement, Size};
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
-use spec::HasTargetSpec;
+use crate::abi::{self, Abi, Align, FieldPlacement, Size};
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::spec::{self, HasTargetSpec};
 
 mod aarch64;
 mod amdgpu;
@@ -42,13 +42,13 @@ pub enum PassMode {
 
 // Hack to disable non_upper_case_globals only for the bitflags! and not for the rest
 // of this module
-pub use self::attr_impl::ArgAttribute;
+pub use attr_impl::ArgAttribute;
 
 #[allow(non_upper_case_globals)]
 #[allow(unused)]
 mod attr_impl {
     // The subset of llvm::Attribute needed for arguments, packed into a bitfield.
-    bitflags! {
+    bitflags::bitflags! {
         #[derive(Default)]
         pub struct ArgAttribute: u16 {
             const ByVal     = 1 << 0;
@@ -160,11 +160,11 @@ pub struct Uniform {
     pub unit: Reg,
 
     /// The total size of the argument, which can be:
-    /// * equal to `unit.size` (one scalar/vector)
-    /// * a multiple of `unit.size` (an array of scalar/vectors)
+    /// * equal to `unit.size` (one scalar/vector),
+    /// * a multiple of `unit.size` (an array of scalar/vectors),
     /// * if `unit.kind` is `Integer`, the last element
     ///   can be shorter, i.e., `{ i64, i64, i32 }` for
-    ///   64-bit integers with a total size of 20 bytes
+    ///   64-bit integers with a total size of 20 bytes.
     pub total: Size,
 }
 
@@ -228,6 +228,33 @@ impl CastTarget {
     }
 }
 
+/// Returns value from the `homogeneous_aggregate` test function.
+#[derive(Copy, Clone, Debug)]
+pub enum HomogeneousAggregate {
+    /// Yes, all the "leaf fields" of this struct are passed in the
+    /// same way (specified in the `Reg` value).
+    Homogeneous(Reg),
+
+    /// There are distinct leaf fields passed in different ways,
+    /// or this is uninhabited.
+    Heterogeneous,
+
+    /// There are no leaf fields at all.
+    NoData,
+}
+
+impl HomogeneousAggregate {
+    /// If this is a homogeneous aggregate, returns the homogeneous
+    /// unit, else `None`.
+    pub fn unit(self) -> Option<Reg> {
+        if let HomogeneousAggregate::Homogeneous(r) = self {
+            Some(r)
+        } else {
+            None
+        }
+    }
+}
+
 impl<'a, Ty> TyLayout<'a, Ty> {
     fn is_aggregate(&self) -> bool {
         match self.abi {
@@ -239,11 +266,21 @@ impl<'a, Ty> TyLayout<'a, Ty> {
         }
     }
 
-    fn homogeneous_aggregate<C>(&self, cx: &C) -> Option<Reg>
+    /// Returns `true` if this layout is an aggregate containing fields of only
+    /// a single type (e.g., `(u32, u32)`). Such aggregates are often
+    /// special-cased in ABIs.
+    ///
+    /// Note: We generally ignore fields of zero-sized type when computing
+    /// this value (see #56877).
+    ///
+    /// This is public so that it can be used in unit tests, but
+    /// should generally only be relevant to the ABI details of
+    /// specific targets.
+    pub fn homogeneous_aggregate<C>(&self, cx: &C) -> HomogeneousAggregate
         where Ty: TyLayoutMethods<'a, C> + Copy, C: LayoutOf<Ty = Ty, TyLayout = Self>
     {
         match self.abi {
-            Abi::Uninhabited => None,
+            Abi::Uninhabited => HomogeneousAggregate::Heterogeneous,
 
             // The primitive for this algorithm.
             Abi::Scalar(ref scalar) => {
@@ -252,14 +289,15 @@ impl<'a, Ty> TyLayout<'a, Ty> {
                     abi::Pointer => RegKind::Integer,
                     abi::Float(_) => RegKind::Float,
                 };
-                Some(Reg {
+                HomogeneousAggregate::Homogeneous(Reg {
                     kind,
                     size: self.size
                 })
             }
 
             Abi::Vector { .. } => {
-                Some(Reg {
+                assert!(!self.is_zst());
+                HomogeneousAggregate::Homogeneous(Reg {
                     kind: RegKind::Vector,
                     size: self.size
                 })
@@ -275,7 +313,7 @@ impl<'a, Ty> TyLayout<'a, Ty> {
                         if count > 0 {
                             return self.field(cx, 0).homogeneous_aggregate(cx);
                         } else {
-                            return None;
+                            return HomogeneousAggregate::NoData;
                         }
                     }
                     FieldPlacement::Union(_) => true,
@@ -284,21 +322,27 @@ impl<'a, Ty> TyLayout<'a, Ty> {
 
                 for i in 0..self.fields.count() {
                     if !is_union && total != self.fields.offset(i) {
-                        return None;
+                        return HomogeneousAggregate::Heterogeneous;
                     }
 
                     let field = self.field(cx, i);
+
                     match (result, field.homogeneous_aggregate(cx)) {
-                        // The field itself must be a homogeneous aggregate.
-                        (_, None) => return None,
+                        (_, HomogeneousAggregate::NoData) => {
+                            // Ignore fields that have no data
+                        }
+                        (_, HomogeneousAggregate::Heterogeneous) => {
+                            // The field itself must be a homogeneous aggregate.
+                            return HomogeneousAggregate::Heterogeneous;
+                        }
                         // If this is the first field, record the unit.
-                        (None, Some(unit)) => {
+                        (None, HomogeneousAggregate::Homogeneous(unit)) => {
                             result = Some(unit);
                         }
                         // For all following fields, the unit must be the same.
-                        (Some(prev_unit), Some(unit)) => {
+                        (Some(prev_unit), HomogeneousAggregate::Homogeneous(unit)) => {
                             if prev_unit != unit {
-                                return None;
+                                return HomogeneousAggregate::Heterogeneous;
                             }
                         }
                     }
@@ -314,9 +358,18 @@ impl<'a, Ty> TyLayout<'a, Ty> {
 
                 // There needs to be no padding.
                 if total != self.size {
-                    None
+                    HomogeneousAggregate::Heterogeneous
                 } else {
-                    result
+                    match result {
+                        Some(reg) => {
+                            assert_ne!(total, Size::ZERO);
+                            HomogeneousAggregate::Homogeneous(reg)
+                        }
+                        None => {
+                            assert_eq!(total, Size::ZERO);
+                            HomogeneousAggregate::NoData
+                        }
+                    }
                 }
             }
         }
@@ -473,22 +526,22 @@ pub struct FnType<'a, Ty> {
 }
 
 impl<'a, Ty> FnType<'a, Ty> {
-    pub fn adjust_for_cabi<C>(&mut self, cx: &C, abi: ::spec::abi::Abi) -> Result<(), String>
+    pub fn adjust_for_cabi<C>(&mut self, cx: &C, abi: spec::abi::Abi) -> Result<(), String>
         where Ty: TyLayoutMethods<'a, C> + Copy,
               C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout + HasTargetSpec
     {
         match &cx.target_spec().arch[..] {
             "x86" => {
-                let flavor = if abi == ::spec::abi::Abi::Fastcall {
+                let flavor = if abi == spec::abi::Abi::Fastcall {
                     x86::Flavor::Fastcall
                 } else {
                     x86::Flavor::General
                 };
                 x86::compute_abi_info(cx, self, flavor);
             },
-            "x86_64" => if abi == ::spec::abi::Abi::SysV64 {
+            "x86_64" => if abi == spec::abi::Abi::SysV64 {
                 x86_64::compute_abi_info(cx, self);
-            } else if abi == ::spec::abi::Abi::Win64 || cx.target_spec().options.is_like_windows {
+            } else if abi == spec::abi::Abi::Win64 || cx.target_spec().options.is_like_windows {
                 x86_win64::compute_abi_info(self);
             } else {
                 x86_64::compute_abi_info(cx, self);
diff --git a/src/librustc_target/abi/call/msp430.rs b/src/librustc_target/abi/call/msp430.rs
index d8ba37db53d4d..7ae1116cba847 100644
--- a/src/librustc_target/abi/call/msp430.rs
+++ b/src/librustc_target/abi/call/msp430.rs
@@ -1,7 +1,7 @@
 // Reference: MSP430 Embedded Application Binary Interface
 // http://www.ti.com/lit/an/slaa534/slaa534.pdf
 
-use abi::call::{ArgType, FnType};
+use crate::abi::call::{ArgType, FnType};
 
 // 3.5 Structures or Unions Passed and Returned by Reference
 //
@@ -9,7 +9,7 @@ use abi::call::{ArgType, FnType};
 // returned by reference. To pass a structure or union by reference, the caller
 // places its address in the appropriate location: either in a register or on
 // the stack, according to its position in the argument list. (..)"
-fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
+fn classify_ret_ty<Ty>(ret: &mut ArgType<'_, Ty>) {
     if ret.layout.is_aggregate() && ret.layout.size.bits() > 32 {
         ret.make_indirect();
     } else {
@@ -17,7 +17,7 @@ fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
     }
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     if arg.layout.is_aggregate() && arg.layout.size.bits() > 32 {
         arg.make_indirect();
     } else {
@@ -25,7 +25,7 @@ fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
     }
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret);
     }
diff --git a/src/librustc_target/abi/call/nvptx.rs b/src/librustc_target/abi/call/nvptx.rs
index 4cf0f11eb1e4a..4722249f73007 100644
--- a/src/librustc_target/abi/call/nvptx.rs
+++ b/src/librustc_target/abi/call/nvptx.rs
@@ -1,9 +1,9 @@
 // Reference: PTX Writer's Guide to Interoperability
 // http://docs.nvidia.com/cuda/ptx-writers-guide-to-interoperability
 
-use abi::call::{ArgType, FnType};
+use crate::abi::call::{ArgType, FnType};
 
-fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
+fn classify_ret_ty<Ty>(ret: &mut ArgType<'_, Ty>) {
     if ret.layout.is_aggregate() && ret.layout.size.bits() > 32 {
         ret.make_indirect();
     } else {
@@ -11,7 +11,7 @@ fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
     }
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     if arg.layout.is_aggregate() && arg.layout.size.bits() > 32 {
         arg.make_indirect();
     } else {
@@ -19,7 +19,7 @@ fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
     }
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret);
     }
diff --git a/src/librustc_target/abi/call/nvptx64.rs b/src/librustc_target/abi/call/nvptx64.rs
index 8ccc77598c90a..51c00ae007c3c 100644
--- a/src/librustc_target/abi/call/nvptx64.rs
+++ b/src/librustc_target/abi/call/nvptx64.rs
@@ -1,9 +1,9 @@
 // Reference: PTX Writer's Guide to Interoperability
 // http://docs.nvidia.com/cuda/ptx-writers-guide-to-interoperability
 
-use abi::call::{ArgType, FnType};
+use crate::abi::call::{ArgType, FnType};
 
-fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
+fn classify_ret_ty<Ty>(ret: &mut ArgType<'_, Ty>) {
     if ret.layout.is_aggregate() && ret.layout.size.bits() > 64 {
         ret.make_indirect();
     } else {
@@ -11,7 +11,7 @@ fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
     }
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     if arg.layout.is_aggregate() && arg.layout.size.bits() > 64 {
         arg.make_indirect();
     } else {
@@ -19,7 +19,7 @@ fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
     }
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret);
     }
diff --git a/src/librustc_target/abi/call/powerpc.rs b/src/librustc_target/abi/call/powerpc.rs
index 2335bfbb5b87b..d496abf8e8b28 100644
--- a/src/librustc_target/abi/call/powerpc.rs
+++ b/src/librustc_target/abi/call/powerpc.rs
@@ -1,7 +1,7 @@
-use abi::call::{ArgType, FnType, Reg, Uniform};
-use abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
+use crate::abi::call::{ArgType, FnType, Reg, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
 
-fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     if !ret.layout.is_aggregate() {
@@ -12,7 +12,7 @@ fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
     }
 }
 
-fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let dl = cx.data_layout();
@@ -34,7 +34,7 @@ fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
     *offset = offset.align_to(align) + size.align_to(align);
 }
 
-pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<Ty>)
+pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<'_, Ty>)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let mut offset = Size::ZERO;
diff --git a/src/librustc_target/abi/call/powerpc64.rs b/src/librustc_target/abi/call/powerpc64.rs
index 3ae9ab9ac5ec9..a9683104d164e 100644
--- a/src/librustc_target/abi/call/powerpc64.rs
+++ b/src/librustc_target/abi/call/powerpc64.rs
@@ -2,23 +2,23 @@
 // Alignment of 128 bit types is not currently handled, this will
 // need to be fixed when PowerPC vector support is added.
 
-use abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
-use abi::{Endian, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
-use spec::HasTargetSpec;
+use crate::abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
+use crate::abi::{Endian, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::spec::HasTargetSpec;
 
 #[derive(Debug, Clone, Copy, PartialEq)]
 enum ABI {
     ELFv1, // original ABI used for powerpc64 (big-endian)
     ELFv2, // newer ABI used for powerpc64le and musl (both endians)
 }
-use self::ABI::*;
+use ABI::*;
 
 fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgType<'a, Ty>, abi: ABI)
                                        -> Option<Uniform>
     where Ty: TyLayoutMethods<'a, C> + Copy,
           C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout
 {
-    arg.layout.homogeneous_aggregate(cx).and_then(|unit| {
+    arg.layout.homogeneous_aggregate(cx).unit().and_then(|unit| {
         // ELFv1 only passes one-member aggregates transparently.
         // ELFv2 passes up to eight uniquely addressable members.
         if (abi == ELFv1 && arg.layout.size > unit.size)
diff --git a/src/librustc_target/abi/call/riscv.rs b/src/librustc_target/abi/call/riscv.rs
index 4950bcd3330aa..ba82e49ddb03e 100644
--- a/src/librustc_target/abi/call/riscv.rs
+++ b/src/librustc_target/abi/call/riscv.rs
@@ -1,9 +1,9 @@
 // Reference: RISC-V ELF psABI specification
 // https://github.com/riscv/riscv-elf-psabi-doc
 
-use abi::call::{ArgType, FnType};
+use crate::abi::call::{ArgType, FnType};
 
-fn classify_ret_ty<Ty>(arg: &mut ArgType<Ty>, xlen: u64) {
+fn classify_ret_ty<Ty>(arg: &mut ArgType<'_, Ty>, xlen: u64) {
     // "Scalars wider than 2✕XLEN are passed by reference and are replaced in
     // the argument list with the address."
     // "Aggregates larger than 2✕XLEN bits are passed by reference and are
@@ -19,7 +19,7 @@ fn classify_ret_ty<Ty>(arg: &mut ArgType<Ty>, xlen: u64) {
     arg.extend_integer_width_to(xlen); // this method only affects integer scalars
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>, xlen: u64) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>, xlen: u64) {
     // "Scalars wider than 2✕XLEN are passed by reference and are replaced in
     // the argument list with the address."
     // "Aggregates larger than 2✕XLEN bits are passed by reference and are
@@ -35,7 +35,7 @@ fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>, xlen: u64) {
     arg.extend_integer_width_to(xlen); // this method only affects integer scalars
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>, xlen: u64) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>, xlen: u64) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret, xlen);
     }
diff --git a/src/librustc_target/abi/call/s390x.rs b/src/librustc_target/abi/call/s390x.rs
index 954c37fee42dd..c2717b1bcb815 100644
--- a/src/librustc_target/abi/call/s390x.rs
+++ b/src/librustc_target/abi/call/s390x.rs
@@ -1,10 +1,10 @@
 // FIXME: The assumes we're using the non-vector ABI, i.e., compiling
 // for a pre-z13 machine or using -mno-vx.
 
-use abi::call::{FnType, ArgType, Reg};
-use abi::{self, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::abi::call::{FnType, ArgType, Reg};
+use crate::abi::{self, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
 
-fn classify_ret_ty<'a, Ty, C>(ret: &mut ArgType<Ty>)
+fn classify_ret_ty<'a, Ty, C>(ret: &mut ArgType<'_, Ty>)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     if !ret.layout.is_aggregate() && ret.layout.size.bits() <= 64 {
diff --git a/src/librustc_target/abi/call/sparc.rs b/src/librustc_target/abi/call/sparc.rs
index 2335bfbb5b87b..d496abf8e8b28 100644
--- a/src/librustc_target/abi/call/sparc.rs
+++ b/src/librustc_target/abi/call/sparc.rs
@@ -1,7 +1,7 @@
-use abi::call::{ArgType, FnType, Reg, Uniform};
-use abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
+use crate::abi::call::{ArgType, FnType, Reg, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, Size, TyLayoutMethods};
 
-fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     if !ret.layout.is_aggregate() {
@@ -12,7 +12,7 @@ fn classify_ret_ty<'a, Ty, C>(cx: &C, ret: &mut ArgType<Ty>, offset: &mut Size)
     }
 }
 
-fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
+fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<'_, Ty>, offset: &mut Size)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let dl = cx.data_layout();
@@ -34,7 +34,7 @@ fn classify_arg_ty<'a, Ty, C>(cx: &C, arg: &mut ArgType<Ty>, offset: &mut Size)
     *offset = offset.align_to(align) + size.align_to(align);
 }
 
-pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<Ty>)
+pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<'_, Ty>)
     where Ty: TyLayoutMethods<'a, C>, C: LayoutOf<Ty = Ty> + HasDataLayout
 {
     let mut offset = Size::ZERO;
diff --git a/src/librustc_target/abi/call/sparc64.rs b/src/librustc_target/abi/call/sparc64.rs
index bb0c9b7967afc..d8930a875efbc 100644
--- a/src/librustc_target/abi/call/sparc64.rs
+++ b/src/librustc_target/abi/call/sparc64.rs
@@ -1,14 +1,14 @@
 // FIXME: This needs an audit for correctness and completeness.
 
-use abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
-use abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::abi::call::{FnType, ArgType, Reg, RegKind, Uniform};
+use crate::abi::{HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
 
 fn is_homogeneous_aggregate<'a, Ty, C>(cx: &C, arg: &mut ArgType<'a, Ty>)
                                      -> Option<Uniform>
     where Ty: TyLayoutMethods<'a, C> + Copy,
           C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout
 {
-    arg.layout.homogeneous_aggregate(cx).and_then(|unit| {
+    arg.layout.homogeneous_aggregate(cx).unit().and_then(|unit| {
         // Ensure we have at most eight uniquely addressable members.
         if arg.layout.size > unit.size.checked_mul(8, cx).unwrap() {
             return None;
diff --git a/src/librustc_target/abi/call/wasm32.rs b/src/librustc_target/abi/call/wasm32.rs
index 78f43f8b508b3..1fdcbb8e39bdf 100644
--- a/src/librustc_target/abi/call/wasm32.rs
+++ b/src/librustc_target/abi/call/wasm32.rs
@@ -1,14 +1,14 @@
-use abi::call::{FnType, ArgType};
+use crate::abi::call::{FnType, ArgType};
 
-fn classify_ret_ty<Ty>(ret: &mut ArgType<Ty>) {
+fn classify_ret_ty<Ty>(ret: &mut ArgType<'_, Ty>) {
     ret.extend_integer_width_to(32);
 }
 
-fn classify_arg_ty<Ty>(arg: &mut ArgType<Ty>) {
+fn classify_arg_ty<Ty>(arg: &mut ArgType<'_, Ty>) {
     arg.extend_integer_width_to(32);
 }
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>) {
     if !fty.ret.is_ignore() {
         classify_ret_ty(&mut fty.ret);
     }
diff --git a/src/librustc_target/abi/call/x86.rs b/src/librustc_target/abi/call/x86.rs
index 748bef4de66b3..2e809571ab18b 100644
--- a/src/librustc_target/abi/call/x86.rs
+++ b/src/librustc_target/abi/call/x86.rs
@@ -1,6 +1,6 @@
-use abi::call::{ArgAttribute, FnType, PassMode, Reg, RegKind};
-use abi::{self, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
-use spec::HasTargetSpec;
+use crate::abi::call::{ArgAttribute, FnType, PassMode, Reg, RegKind};
+use crate::abi::{self, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods};
+use crate::spec::HasTargetSpec;
 
 #[derive(PartialEq)]
 pub enum Flavor {
@@ -99,7 +99,7 @@ pub fn compute_abi_info<'a, Ty, C>(cx: &C, fty: &mut FnType<'a, Ty>, flavor: Fla
             };
 
             // At this point we know this must be a primitive of sorts.
-            let unit = arg.layout.homogeneous_aggregate(cx).unwrap();
+            let unit = arg.layout.homogeneous_aggregate(cx).unit().unwrap();
             assert_eq!(unit.size, arg.layout.size);
             if unit.kind == RegKind::Float {
                 continue;
diff --git a/src/librustc_target/abi/call/x86_64.rs b/src/librustc_target/abi/call/x86_64.rs
index 9d8cc19aac524..680e529b108e0 100644
--- a/src/librustc_target/abi/call/x86_64.rs
+++ b/src/librustc_target/abi/call/x86_64.rs
@@ -1,8 +1,8 @@
 // The classification code for the x86_64 ABI is taken from the clay language
 // https://github.com/jckarter/clay/blob/master/compiler/src/externals.cpp
 
-use abi::call::{ArgType, CastTarget, FnType, Reg, RegKind};
-use abi::{self, Abi, HasDataLayout, LayoutOf, Size, TyLayout, TyLayoutMethods};
+use crate::abi::call::{ArgType, CastTarget, FnType, Reg, RegKind};
+use crate::abi::{self, Abi, HasDataLayout, LayoutOf, Size, TyLayout, TyLayoutMethods};
 
 /// Classification of "eightbyte" components.
 // N.B., the order of the variants is from general to specific,
diff --git a/src/librustc_target/abi/call/x86_win64.rs b/src/librustc_target/abi/call/x86_win64.rs
index c583f7a0a2a24..ebdeb63150a46 100644
--- a/src/librustc_target/abi/call/x86_win64.rs
+++ b/src/librustc_target/abi/call/x86_win64.rs
@@ -1,10 +1,10 @@
-use abi::call::{ArgType, FnType, Reg};
-use abi::Abi;
+use crate::abi::call::{ArgType, FnType, Reg};
+use crate::abi::Abi;
 
 // Win64 ABI: http://msdn.microsoft.com/en-us/library/zthk2dkh.aspx
 
-pub fn compute_abi_info<Ty>(fty: &mut FnType<Ty>) {
-    let fixup = |a: &mut ArgType<Ty>| {
+pub fn compute_abi_info<Ty>(fty: &mut FnType<'_, Ty>) {
+    let fixup = |a: &mut ArgType<'_, Ty>| {
         match a.layout.abi {
             Abi::Uninhabited => {}
             Abi::ScalarPair(..) |
diff --git a/src/librustc_target/abi/mod.rs b/src/librustc_target/abi/mod.rs
index 3f95e666535be..8b96a8c1658b2 100644
--- a/src/librustc_target/abi/mod.rs
+++ b/src/librustc_target/abi/mod.rs
@@ -1,7 +1,7 @@
-pub use self::Integer::*;
-pub use self::Primitive::*;
+pub use Integer::*;
+pub use Primitive::*;
 
-use spec::Target;
+use crate::spec::Target;
 
 use std::fmt;
 use std::ops::{Add, Deref, Sub, Mul, AddAssign, Range, RangeInclusive};
@@ -174,7 +174,7 @@ impl TargetDataLayout {
         Ok(dl)
     }
 
-    /// Return exclusive upper bound on object size.
+    /// Returns exclusive upper bound on object size.
     ///
     /// The theoretical maximum object size is defined as the maximum positive `isize` value.
     /// This ensures that the `offset` semantics remain well-defined by allowing it to correctly
@@ -396,7 +396,7 @@ impl Align {
         self.bytes() * 8
     }
 
-    /// Compute the best alignment possible for the given offset
+    /// Computes the best alignment possible for the given offset
     /// (the largest power of two that the offset is a multiple of).
     ///
     /// N.B., for an offset of `0`, this happens to return `2^64`.
@@ -476,7 +476,7 @@ impl Integer {
         }
     }
 
-    /// Find the smallest Integer type which can represent the signed value.
+    /// Finds the smallest Integer type which can represent the signed value.
     pub fn fit_signed(x: i128) -> Integer {
         match x {
             -0x0000_0000_0000_0080..=0x0000_0000_0000_007f => I8,
@@ -487,7 +487,7 @@ impl Integer {
         }
     }
 
-    /// Find the smallest Integer type which can represent the unsigned value.
+    /// Finds the smallest Integer type which can represent the unsigned value.
     pub fn fit_unsigned(x: u128) -> Integer {
         match x {
             0..=0x0000_0000_0000_00ff => I8,
@@ -498,7 +498,7 @@ impl Integer {
         }
     }
 
-    /// Find the smallest integer with the given alignment.
+    /// Finds the smallest integer with the given alignment.
     pub fn for_align<C: HasDataLayout>(cx: &C, wanted: Align) -> Option<Integer> {
         let dl = cx.data_layout();
 
@@ -533,13 +533,13 @@ pub enum FloatTy {
 }
 
 impl fmt::Debug for FloatTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self, f)
     }
 }
 
 impl fmt::Display for FloatTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.ty_to_string())
     }
 }
@@ -734,7 +734,7 @@ impl FieldPlacement {
         }
     }
 
-    /// Get source indices of the fields by increasing offsets.
+    /// Gets source indices of the fields by increasing offsets.
     #[inline]
     pub fn index_by_increasing_offset<'a>(&'a self) -> impl Iterator<Item=usize>+'a {
         let mut inverse_small = [0u8; 64];
@@ -786,7 +786,7 @@ pub enum Abi {
 }
 
 impl Abi {
-    /// Returns true if the layout corresponds to an unsized type.
+    /// Returns `true` if the layout corresponds to an unsized type.
     pub fn is_unsized(&self) -> bool {
         match *self {
             Abi::Uninhabited |
@@ -797,7 +797,7 @@ impl Abi {
         }
     }
 
-    /// Returns true if this is a single signed integer scalar
+    /// Returns `true` if this is a single signed integer scalar
     pub fn is_signed(&self) -> bool {
         match *self {
             Abi::Scalar(ref scal) => match scal.value {
@@ -808,7 +808,7 @@ impl Abi {
         }
     }
 
-    /// Returns true if this is an uninhabited type
+    /// Returns `true` if this is an uninhabited type
     pub fn is_uninhabited(&self) -> bool {
         match *self {
             Abi::Uninhabited => true,
@@ -924,12 +924,12 @@ impl<'a, Ty> TyLayout<'a, Ty> {
 }
 
 impl<'a, Ty> TyLayout<'a, Ty> {
-    /// Returns true if the layout corresponds to an unsized type.
+    /// Returns `true` if the layout corresponds to an unsized type.
     pub fn is_unsized(&self) -> bool {
         self.abi.is_unsized()
     }
 
-    /// Returns true if the type is a ZST and not unsized.
+    /// Returns `true` if the type is a ZST and not unsized.
     pub fn is_zst(&self) -> bool {
         match self.abi {
             Abi::Scalar(_) |
diff --git a/src/librustc_target/lib.rs b/src/librustc_target/lib.rs
index 0df0027c171aa..efffb1985728d 100644
--- a/src/librustc_target/lib.rs
+++ b/src/librustc_target/lib.rs
@@ -4,12 +4,10 @@
 //! compiler 'backend', though LLVM is rustc's backend, so rustc_target
 //! is really just odds-and-ends relating to code gen and linking.
 //! This crate mostly exists to make rustc smaller, so we might put
-//! more 'stuff' here in the future.  It does not have a dependency on
+//! more 'stuff' here in the future. It does not have a dependency on
 //! LLVM.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![feature(box_syntax)]
 #![feature(nll)]
@@ -17,11 +15,11 @@
 #![feature(slice_patterns)]
 #![feature(step_trait)]
 
-#[macro_use]
-extern crate bitflags;
-extern crate serialize;
+#![deny(rust_2018_idioms)]
+
 #[macro_use] extern crate log;
 
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
 
 // See librustc_cratesio_shim/Cargo.toml for a comment explaining this.
diff --git a/src/librustc_target/spec/aarch64_apple_ios.rs b/src/librustc_target/spec/aarch64_apple_ios.rs
index 2210fd1e9e7c9..8bdc08c788d01 100644
--- a/src/librustc_target/spec/aarch64_apple_ios.rs
+++ b/src/librustc_target/spec/aarch64_apple_ios.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/aarch64_fuchsia.rs b/src/librustc_target/spec/aarch64_fuchsia.rs
index e39a1c2e1068c..308954d56f8bf 100644
--- a/src/librustc_target/spec/aarch64_fuchsia.rs
+++ b/src/librustc_target/spec/aarch64_fuchsia.rs
@@ -1,4 +1,4 @@
-use spec::{LldFlavor, LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LldFlavor, LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::fuchsia_base::opts();
diff --git a/src/librustc_target/spec/aarch64_linux_android.rs b/src/librustc_target/spec/aarch64_linux_android.rs
index c05964295d37a..65160f6231e8c 100644
--- a/src/librustc_target/spec/aarch64_linux_android.rs
+++ b/src/librustc_target/spec/aarch64_linux_android.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // See https://developer.android.com/ndk/guides/abis.html#arm64-v8a
 // for target ABI requirements.
diff --git a/src/librustc_target/spec/aarch64_pc_windows_msvc.rs b/src/librustc_target/spec/aarch64_pc_windows_msvc.rs
index b33430b59e8f9..1aee381d604c3 100644
--- a/src/librustc_target/spec/aarch64_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/aarch64_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult, PanicStrategy};
+use crate::spec::{LinkerFlavor, Target, TargetResult, PanicStrategy};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_cloudabi.rs b/src/librustc_target/spec/aarch64_unknown_cloudabi.rs
index ac3345ce3f214..7141954306769 100644
--- a/src/librustc_target/spec/aarch64_unknown_cloudabi.rs
+++ b/src/librustc_target/spec/aarch64_unknown_cloudabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::cloudabi_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_freebsd.rs b/src/librustc_target/spec/aarch64_unknown_freebsd.rs
index 1fb0a2bcf7c22..36860649c53ad 100644
--- a/src/librustc_target/spec/aarch64_unknown_freebsd.rs
+++ b/src/librustc_target/spec/aarch64_unknown_freebsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::freebsd_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_hermit.rs b/src/librustc_target/spec/aarch64_unknown_hermit.rs
index 26006d0060d49..7b020605102b1 100644
--- a/src/librustc_target/spec/aarch64_unknown_hermit.rs
+++ b/src/librustc_target/spec/aarch64_unknown_hermit.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::hermit_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_linux_gnu.rs b/src/librustc_target/spec/aarch64_unknown_linux_gnu.rs
index d30d927b6dd3d..e772d8b532cb0 100644
--- a/src/librustc_target/spec/aarch64_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/aarch64_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_linux_musl.rs b/src/librustc_target/spec/aarch64_unknown_linux_musl.rs
index 258725fed15be..8123ee82ed524 100644
--- a/src/librustc_target/spec/aarch64_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/aarch64_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_netbsd.rs b/src/librustc_target/spec/aarch64_unknown_netbsd.rs
index 10aef8f923d4c..47ae08ade9a6b 100644
--- a/src/librustc_target/spec/aarch64_unknown_netbsd.rs
+++ b/src/librustc_target/spec/aarch64_unknown_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/aarch64_unknown_none.rs b/src/librustc_target/spec/aarch64_unknown_none.rs
index 3440a4f8752db..8c02bc61088b4 100644
--- a/src/librustc_target/spec/aarch64_unknown_none.rs
+++ b/src/librustc_target/spec/aarch64_unknown_none.rs
@@ -11,6 +11,7 @@ use super::{LldFlavor, LinkerFlavor, Target, TargetOptions, PanicStrategy};
 pub fn target() -> Result<Target, String> {
     let opts = TargetOptions {
         linker: Some("rust-lld".to_owned()),
+        features: "+strict-align".to_string(),
         executables: true,
         relocation_model: "static".to_string(),
         disable_redzone: true,
diff --git a/src/librustc_target/spec/aarch64_unknown_openbsd.rs b/src/librustc_target/spec/aarch64_unknown_openbsd.rs
index 815e11a919c0f..c9cd64c3a84af 100644
--- a/src/librustc_target/spec/aarch64_unknown_openbsd.rs
+++ b/src/librustc_target/spec/aarch64_unknown_openbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::openbsd_base::opts();
diff --git a/src/librustc_target/spec/abi.rs b/src/librustc_target/spec/abi.rs
index 46606e707d757..c9c41f1092240 100644
--- a/src/librustc_target/spec/abi.rs
+++ b/src/librustc_target/spec/abi.rs
@@ -96,7 +96,7 @@ impl Abi {
 }
 
 impl fmt::Display for Abi {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "\"{}\"", self.name())
     }
 }
diff --git a/src/librustc_target/spec/android_base.rs b/src/librustc_target/spec/android_base.rs
index a8f8ad3185f0d..684c059b41482 100644
--- a/src/librustc_target/spec/android_base.rs
+++ b/src/librustc_target/spec/android_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, TargetOptions};
+use crate::spec::{LinkerFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/apple_base.rs b/src/librustc_target/spec/apple_base.rs
index a80d1904a7471..c21f7f38ca5a3 100644
--- a/src/librustc_target/spec/apple_base.rs
+++ b/src/librustc_target/spec/apple_base.rs
@@ -1,6 +1,6 @@
 use std::env;
 
-use spec::{LinkArgs, TargetOptions};
+use crate::spec::{LinkArgs, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     // ELF TLS is only available in macOS 10.7+. If you try to compile for 10.6
diff --git a/src/librustc_target/spec/apple_ios_base.rs b/src/librustc_target/spec/apple_ios_base.rs
index 72346ab1f34b6..3068ed8d206cd 100644
--- a/src/librustc_target/spec/apple_ios_base.rs
+++ b/src/librustc_target/spec/apple_ios_base.rs
@@ -1,8 +1,8 @@
 use std::io;
 use std::process::Command;
-use spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 
-use self::Arch::*;
+use Arch::*;
 
 #[allow(non_camel_case_types)]
 #[derive(Copy, Clone)]
diff --git a/src/librustc_target/spec/arm_base.rs b/src/librustc_target/spec/arm_base.rs
index 1d51d60c8f258..77e7bfac62d58 100644
--- a/src/librustc_target/spec/arm_base.rs
+++ b/src/librustc_target/spec/arm_base.rs
@@ -1,4 +1,4 @@
-use spec::abi::Abi;
+use crate::spec::abi::Abi;
 
 // All the calling conventions trigger an assertion(Unsupported calling convention) in llvm on arm
 pub fn abi_blacklist() -> Vec<Abi> {
diff --git a/src/librustc_target/spec/arm_linux_androideabi.rs b/src/librustc_target/spec/arm_linux_androideabi.rs
index 5e4bebfa1c1a4..bb066dc9ad833 100644
--- a/src/librustc_target/spec/arm_linux_androideabi.rs
+++ b/src/librustc_target/spec/arm_linux_androideabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::android_base::opts();
diff --git a/src/librustc_target/spec/arm_unknown_linux_gnueabi.rs b/src/librustc_target/spec/arm_unknown_linux_gnueabi.rs
index 0f891dacc6dbf..f291818ba80f5 100644
--- a/src/librustc_target/spec/arm_unknown_linux_gnueabi.rs
+++ b/src/librustc_target/spec/arm_unknown_linux_gnueabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/arm_unknown_linux_gnueabihf.rs b/src/librustc_target/spec/arm_unknown_linux_gnueabihf.rs
index 5503bf326cd7b..32b509d9721ef 100644
--- a/src/librustc_target/spec/arm_unknown_linux_gnueabihf.rs
+++ b/src/librustc_target/spec/arm_unknown_linux_gnueabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/arm_unknown_linux_musleabi.rs b/src/librustc_target/spec/arm_unknown_linux_musleabi.rs
index c2162beba26e8..7637577e7e848 100644
--- a/src/librustc_target/spec/arm_unknown_linux_musleabi.rs
+++ b/src/librustc_target/spec/arm_unknown_linux_musleabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/arm_unknown_linux_musleabihf.rs b/src/librustc_target/spec/arm_unknown_linux_musleabihf.rs
index b3f00331b3c9e..9def151b3ef29 100644
--- a/src/librustc_target/spec/arm_unknown_linux_musleabihf.rs
+++ b/src/librustc_target/spec/arm_unknown_linux_musleabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/armebv7r_none_eabi.rs b/src/librustc_target/spec/armebv7r_none_eabi.rs
index cd41ffbab4d9c..86c62daa6180a 100644
--- a/src/librustc_target/spec/armebv7r_none_eabi.rs
+++ b/src/librustc_target/spec/armebv7r_none_eabi.rs
@@ -1,7 +1,7 @@
 // Targets the Big endian Cortex-R4/R5 processor (ARMv7-R)
 
 use std::default::Default;
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armebv7r_none_eabihf.rs b/src/librustc_target/spec/armebv7r_none_eabihf.rs
index 05b12dd28bacd..50ee76414ef9a 100644
--- a/src/librustc_target/spec/armebv7r_none_eabihf.rs
+++ b/src/librustc_target/spec/armebv7r_none_eabihf.rs
@@ -1,7 +1,7 @@
 // Targets the Cortex-R4F/R5F processor (ARMv7-R)
 
 use std::default::Default;
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armv4t_unknown_linux_gnueabi.rs b/src/librustc_target/spec/armv4t_unknown_linux_gnueabi.rs
index 7fe021e5327b9..7cd4b14cdebc8 100644
--- a/src/librustc_target/spec/armv4t_unknown_linux_gnueabi.rs
+++ b/src/librustc_target/spec/armv4t_unknown_linux_gnueabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/armv5te_unknown_linux_gnueabi.rs b/src/librustc_target/spec/armv5te_unknown_linux_gnueabi.rs
index c85a80f6e8a4c..15f614827718b 100644
--- a/src/librustc_target/spec/armv5te_unknown_linux_gnueabi.rs
+++ b/src/librustc_target/spec/armv5te_unknown_linux_gnueabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/armv5te_unknown_linux_musleabi.rs b/src/librustc_target/spec/armv5te_unknown_linux_musleabi.rs
index dce767898c06b..74915b942ea4f 100644
--- a/src/librustc_target/spec/armv5te_unknown_linux_musleabi.rs
+++ b/src/librustc_target/spec/armv5te_unknown_linux_musleabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/armv6_unknown_netbsd_eabihf.rs b/src/librustc_target/spec/armv6_unknown_netbsd_eabihf.rs
index 95cc41e6c98fb..e460b6c574a26 100644
--- a/src/librustc_target/spec/armv6_unknown_netbsd_eabihf.rs
+++ b/src/librustc_target/spec/armv6_unknown_netbsd_eabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/armv7_apple_ios.rs b/src/librustc_target/spec/armv7_apple_ios.rs
index 98018215c805a..2052d17403dfd 100644
--- a/src/librustc_target/spec/armv7_apple_ios.rs
+++ b/src/librustc_target/spec/armv7_apple_ios.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/armv7_linux_androideabi.rs b/src/librustc_target/spec/armv7_linux_androideabi.rs
index 65c3c7f7057ab..92f1a55e024d7 100644
--- a/src/librustc_target/spec/armv7_linux_androideabi.rs
+++ b/src/librustc_target/spec/armv7_linux_androideabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // This target if is for the baseline of the Android v7a ABI
 // in thumb mode. It's named armv7-* instead of thumbv7-*
diff --git a/src/librustc_target/spec/armv7_unknown_cloudabi_eabihf.rs b/src/librustc_target/spec/armv7_unknown_cloudabi_eabihf.rs
index fa43879dccab8..a6c7fb537c785 100644
--- a/src/librustc_target/spec/armv7_unknown_cloudabi_eabihf.rs
+++ b/src/librustc_target/spec/armv7_unknown_cloudabi_eabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::cloudabi_base::opts();
diff --git a/src/librustc_target/spec/armv7_unknown_linux_gnueabihf.rs b/src/librustc_target/spec/armv7_unknown_linux_gnueabihf.rs
index 864c59b81844e..f16215433c766 100644
--- a/src/librustc_target/spec/armv7_unknown_linux_gnueabihf.rs
+++ b/src/librustc_target/spec/armv7_unknown_linux_gnueabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // This target is for glibc Linux on ARMv7 without NEON or
 // thumb-mode. See the thumbv7neon variant for enabling both.
diff --git a/src/librustc_target/spec/armv7_unknown_linux_musleabihf.rs b/src/librustc_target/spec/armv7_unknown_linux_musleabihf.rs
index ae0cb2c08b430..45a26966b716b 100644
--- a/src/librustc_target/spec/armv7_unknown_linux_musleabihf.rs
+++ b/src/librustc_target/spec/armv7_unknown_linux_musleabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // This target is for musl Linux on ARMv7 without thumb-mode or NEON.
 
diff --git a/src/librustc_target/spec/armv7_unknown_netbsd_eabihf.rs b/src/librustc_target/spec/armv7_unknown_netbsd_eabihf.rs
index f9e416fd06e92..44e2636e9188e 100644
--- a/src/librustc_target/spec/armv7_unknown_netbsd_eabihf.rs
+++ b/src/librustc_target/spec/armv7_unknown_netbsd_eabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     let base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/armv7r_none_eabi.rs b/src/librustc_target/spec/armv7r_none_eabi.rs
index 38d115bc85e7f..19d332467dec5 100644
--- a/src/librustc_target/spec/armv7r_none_eabi.rs
+++ b/src/librustc_target/spec/armv7r_none_eabi.rs
@@ -1,7 +1,7 @@
 // Targets the Little-endian Cortex-R4/R5 processor (ARMv7-R)
 
 use std::default::Default;
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armv7r_none_eabihf.rs b/src/librustc_target/spec/armv7r_none_eabihf.rs
index cb707f7183a49..06ef9f3ec4e37 100644
--- a/src/librustc_target/spec/armv7r_none_eabihf.rs
+++ b/src/librustc_target/spec/armv7r_none_eabihf.rs
@@ -1,7 +1,7 @@
 // Targets the Little-endian Cortex-R4F/R5F processor (ARMv7-R)
 
 use std::default::Default;
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/armv7s_apple_ios.rs b/src/librustc_target/spec/armv7s_apple_ios.rs
index 6d9635b308e90..29e290285e4a9 100644
--- a/src/librustc_target/spec/armv7s_apple_ios.rs
+++ b/src/librustc_target/spec/armv7s_apple_ios.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/bitrig_base.rs b/src/librustc_target/spec/bitrig_base.rs
index 3b6985fa4c826..9b34119fc00c9 100644
--- a/src/librustc_target/spec/bitrig_base.rs
+++ b/src/librustc_target/spec/bitrig_base.rs
@@ -1,4 +1,4 @@
-use spec::{TargetOptions, RelroLevel};
+use crate::spec::{TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/cloudabi_base.rs b/src/librustc_target/spec/cloudabi_base.rs
index 145de0ebe6995..a34122d3e0fe2 100644
--- a/src/librustc_target/spec/cloudabi_base.rs
+++ b/src/librustc_target/spec/cloudabi_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 
 pub fn opts() -> TargetOptions {
     let mut args = LinkArgs::new();
diff --git a/src/librustc_target/spec/dragonfly_base.rs b/src/librustc_target/spec/dragonfly_base.rs
index 6ce2912da75cf..766030e8015d0 100644
--- a/src/librustc_target/spec/dragonfly_base.rs
+++ b/src/librustc_target/spec/dragonfly_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/freebsd_base.rs b/src/librustc_target/spec/freebsd_base.rs
index 47316f77e634e..51f030f59084d 100644
--- a/src/librustc_target/spec/freebsd_base.rs
+++ b/src/librustc_target/spec/freebsd_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/fuchsia_base.rs b/src/librustc_target/spec/fuchsia_base.rs
index 5d94f308410a6..4e4f2fa0cf34c 100644
--- a/src/librustc_target/spec/fuchsia_base.rs
+++ b/src/librustc_target/spec/fuchsia_base.rs
@@ -1,4 +1,4 @@
-use spec::{LldFlavor, LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LldFlavor, LinkArgs, LinkerFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/haiku_base.rs b/src/librustc_target/spec/haiku_base.rs
index 00c6bd40dc584..d071062705306 100644
--- a/src/librustc_target/spec/haiku_base.rs
+++ b/src/librustc_target/spec/haiku_base.rs
@@ -1,4 +1,4 @@
-use spec::{TargetOptions, RelroLevel};
+use crate::spec::{TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/hermit_base.rs b/src/librustc_target/spec/hermit_base.rs
index d7d8562e055d8..ee753393ddb3d 100644
--- a/src/librustc_target/spec/hermit_base.rs
+++ b/src/librustc_target/spec/hermit_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, PanicStrategy, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, PanicStrategy, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/i386_apple_ios.rs b/src/librustc_target/spec/i386_apple_ios.rs
index d0e317630013b..78e9cbb61ef58 100644
--- a/src/librustc_target/spec/i386_apple_ios.rs
+++ b/src/librustc_target/spec/i386_apple_ios.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/i586_pc_windows_msvc.rs b/src/librustc_target/spec/i586_pc_windows_msvc.rs
index 12a7f98beff95..ba712aced8474 100644
--- a/src/librustc_target/spec/i586_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/i586_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use spec::TargetResult;
+use crate::spec::TargetResult;
 
 pub fn target() -> TargetResult {
     let mut base = super::i686_pc_windows_msvc::target()?;
diff --git a/src/librustc_target/spec/i586_unknown_linux_gnu.rs b/src/librustc_target/spec/i586_unknown_linux_gnu.rs
index 76f6a4eba389f..49f4f2cb6b999 100644
--- a/src/librustc_target/spec/i586_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/i586_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::TargetResult;
+use crate::spec::TargetResult;
 
 pub fn target() -> TargetResult {
     let mut base = super::i686_unknown_linux_gnu::target()?;
diff --git a/src/librustc_target/spec/i586_unknown_linux_musl.rs b/src/librustc_target/spec/i586_unknown_linux_musl.rs
index 2b56fd7a7e370..0f2ccebd6dace 100644
--- a/src/librustc_target/spec/i586_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/i586_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::TargetResult;
+use crate::spec::TargetResult;
 
 pub fn target() -> TargetResult {
     let mut base = super::i686_unknown_linux_musl::target()?;
diff --git a/src/librustc_target/spec/i686_apple_darwin.rs b/src/librustc_target/spec/i686_apple_darwin.rs
index 40d9588e463a6..c8a61296d33d2 100644
--- a/src/librustc_target/spec/i686_apple_darwin.rs
+++ b/src/librustc_target/spec/i686_apple_darwin.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::apple_base::opts();
diff --git a/src/librustc_target/spec/i686_linux_android.rs b/src/librustc_target/spec/i686_linux_android.rs
index 5b8cb7ac55d58..3f73d24ee848b 100644
--- a/src/librustc_target/spec/i686_linux_android.rs
+++ b/src/librustc_target/spec/i686_linux_android.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 // See https://developer.android.com/ndk/guides/abis.html#x86
 // for target ABI requirements.
diff --git a/src/librustc_target/spec/i686_pc_windows_gnu.rs b/src/librustc_target/spec/i686_pc_windows_gnu.rs
index d7bc38ca172d5..12214a7d53119 100644
--- a/src/librustc_target/spec/i686_pc_windows_gnu.rs
+++ b/src/librustc_target/spec/i686_pc_windows_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_base::opts();
diff --git a/src/librustc_target/spec/i686_pc_windows_msvc.rs b/src/librustc_target/spec/i686_pc_windows_msvc.rs
index f0d75ae4e9bdd..1967834819ab2 100644
--- a/src/librustc_target/spec/i686_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/i686_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_cloudabi.rs b/src/librustc_target/spec/i686_unknown_cloudabi.rs
index 3a9e424698127..f3b40633b4007 100644
--- a/src/librustc_target/spec/i686_unknown_cloudabi.rs
+++ b/src/librustc_target/spec/i686_unknown_cloudabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::cloudabi_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_dragonfly.rs b/src/librustc_target/spec/i686_unknown_dragonfly.rs
index 9d71c5a823361..20315e7145c73 100644
--- a/src/librustc_target/spec/i686_unknown_dragonfly.rs
+++ b/src/librustc_target/spec/i686_unknown_dragonfly.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::dragonfly_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_freebsd.rs b/src/librustc_target/spec/i686_unknown_freebsd.rs
index 627dffa89d247..71f05a140f3df 100644
--- a/src/librustc_target/spec/i686_unknown_freebsd.rs
+++ b/src/librustc_target/spec/i686_unknown_freebsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::freebsd_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_haiku.rs b/src/librustc_target/spec/i686_unknown_haiku.rs
index 86c64ce684bb8..b807e4eee39a5 100644
--- a/src/librustc_target/spec/i686_unknown_haiku.rs
+++ b/src/librustc_target/spec/i686_unknown_haiku.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::haiku_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_linux_gnu.rs b/src/librustc_target/spec/i686_unknown_linux_gnu.rs
index ab38832831157..5875cbf78bfe6 100644
--- a/src/librustc_target/spec/i686_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/i686_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_linux_musl.rs b/src/librustc_target/spec/i686_unknown_linux_musl.rs
index 81cbf57e577a6..732949034e824 100644
--- a/src/librustc_target/spec/i686_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/i686_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_netbsd.rs b/src/librustc_target/spec/i686_unknown_netbsd.rs
index 1027e240224c9..e8a9f29ea5f4c 100644
--- a/src/librustc_target/spec/i686_unknown_netbsd.rs
+++ b/src/librustc_target/spec/i686_unknown_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/i686_unknown_openbsd.rs b/src/librustc_target/spec/i686_unknown_openbsd.rs
index d2bbc6bb2dbaf..d7c323e0d8a8a 100644
--- a/src/librustc_target/spec/i686_unknown_openbsd.rs
+++ b/src/librustc_target/spec/i686_unknown_openbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::openbsd_base::opts();
diff --git a/src/librustc_target/spec/l4re_base.rs b/src/librustc_target/spec/l4re_base.rs
index 951005998be07..9317f053efe70 100644
--- a/src/librustc_target/spec/l4re_base.rs
+++ b/src/librustc_target/spec/l4re_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, PanicStrategy, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, PanicStrategy, TargetOptions};
 use std::default::Default;
 //use std::process::Command;
 
diff --git a/src/librustc_target/spec/linux_base.rs b/src/librustc_target/spec/linux_base.rs
index b036bf81a7542..195fba3915f94 100644
--- a/src/librustc_target/spec/linux_base.rs
+++ b/src/librustc_target/spec/linux_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/linux_musl_base.rs b/src/librustc_target/spec/linux_musl_base.rs
index 1bc90d1a73287..e294e63982de4 100644
--- a/src/librustc_target/spec/linux_musl_base.rs
+++ b/src/librustc_target/spec/linux_musl_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, TargetOptions};
+use crate::spec::{LinkerFlavor, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/mips64_unknown_linux_gnuabi64.rs b/src/librustc_target/spec/mips64_unknown_linux_gnuabi64.rs
index 650f38702b67b..3b38e64050f3b 100644
--- a/src/librustc_target/spec/mips64_unknown_linux_gnuabi64.rs
+++ b/src/librustc_target/spec/mips64_unknown_linux_gnuabi64.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mips64el_unknown_linux_gnuabi64.rs b/src/librustc_target/spec/mips64el_unknown_linux_gnuabi64.rs
index cb348d49479b9..0f6cd86d616d8 100644
--- a/src/librustc_target/spec/mips64el_unknown_linux_gnuabi64.rs
+++ b/src/librustc_target/spec/mips64el_unknown_linux_gnuabi64.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mips_unknown_linux_gnu.rs b/src/librustc_target/spec/mips_unknown_linux_gnu.rs
index 6cc3d30be1fb0..b4d29c5fbeaf4 100644
--- a/src/librustc_target/spec/mips_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/mips_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mips_unknown_linux_musl.rs b/src/librustc_target/spec/mips_unknown_linux_musl.rs
index 152b11b4aeeb5..c56c6e3822959 100644
--- a/src/librustc_target/spec/mips_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/mips_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/mips_unknown_linux_uclibc.rs b/src/librustc_target/spec/mips_unknown_linux_uclibc.rs
index 99cd20e9a52e8..cb02769c7dfe4 100644
--- a/src/librustc_target/spec/mips_unknown_linux_uclibc.rs
+++ b/src/librustc_target/spec/mips_unknown_linux_uclibc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mipsel_unknown_linux_gnu.rs b/src/librustc_target/spec/mipsel_unknown_linux_gnu.rs
index 476cf15270649..ed49ddd49937f 100644
--- a/src/librustc_target/spec/mipsel_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/mipsel_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mipsel_unknown_linux_musl.rs b/src/librustc_target/spec/mipsel_unknown_linux_musl.rs
index 9df131dbe2510..bcc49cf5ffe4f 100644
--- a/src/librustc_target/spec/mipsel_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/mipsel_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/mipsel_unknown_linux_uclibc.rs b/src/librustc_target/spec/mipsel_unknown_linux_uclibc.rs
index 37c55d11f25c9..205f328a24cec 100644
--- a/src/librustc_target/spec/mipsel_unknown_linux_uclibc.rs
+++ b/src/librustc_target/spec/mipsel_unknown_linux_uclibc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index f42b0a1c3c958..bef2afc7b6292 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -40,7 +40,7 @@ use std::default::Default;
 use std::{fmt, io};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
-use spec::abi::{Abi, lookup as lookup_abi};
+use crate::spec::abi::{Abi, lookup as lookup_abi};
 
 pub mod abi;
 mod android_base;
@@ -75,6 +75,7 @@ pub enum LinkerFlavor {
     Ld,
     Msvc,
     Lld(LldFlavor),
+    PtxLinker,
 }
 
 #[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, Hash,
@@ -143,6 +144,7 @@ flavor_mappings! {
     ((LinkerFlavor::Gcc), "gcc"),
     ((LinkerFlavor::Ld), "ld"),
     ((LinkerFlavor::Msvc), "msvc"),
+    ((LinkerFlavor::PtxLinker), "ptx-linker"),
     ((LinkerFlavor::Lld(LldFlavor::Wasm)), "wasm-ld"),
     ((LinkerFlavor::Lld(LldFlavor::Ld64)), "ld64.lld"),
     ((LinkerFlavor::Lld(LldFlavor::Ld)), "ld.lld"),
@@ -217,6 +219,51 @@ impl ToJson for RelroLevel {
     }
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Hash, RustcEncodable, RustcDecodable)]
+pub enum MergeFunctions {
+    Disabled,
+    Trampolines,
+    Aliases
+}
+
+impl MergeFunctions {
+    pub fn desc(&self) -> &str {
+        match *self {
+            MergeFunctions::Disabled => "disabled",
+            MergeFunctions::Trampolines => "trampolines",
+            MergeFunctions::Aliases => "aliases",
+        }
+    }
+}
+
+impl FromStr for MergeFunctions {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<MergeFunctions, ()> {
+        match s {
+            "disabled" => Ok(MergeFunctions::Disabled),
+            "trampolines" => Ok(MergeFunctions::Trampolines),
+            "aliases" => Ok(MergeFunctions::Aliases),
+            _ => Err(()),
+        }
+    }
+}
+
+impl ToJson for MergeFunctions {
+    fn to_json(&self) -> Json {
+        match *self {
+            MergeFunctions::Disabled => "disabled".to_json(),
+            MergeFunctions::Trampolines => "trampolines".to_json(),
+            MergeFunctions::Aliases => "aliases".to_json(),
+        }
+    }
+}
+
+pub enum LoadTargetError {
+    BuiltinTargetNotFound(String),
+    Other(String),
+}
+
 pub type LinkArgs = BTreeMap<LinkerFlavor, Vec<String>>;
 pub type TargetResult = Result<Target, String>;
 
@@ -227,21 +274,24 @@ macro_rules! supported_targets {
         /// List of supported targets
         const TARGETS: &[&str] = &[$($triple),*];
 
-        fn load_specific(target: &str) -> TargetResult {
+        fn load_specific(target: &str) -> Result<Target, LoadTargetError> {
             match target {
                 $(
                     $triple => {
-                        let mut t = $module::target()?;
+                        let mut t = $module::target()
+                            .map_err(LoadTargetError::Other)?;
                         t.options.is_builtin = true;
 
                         // round-trip through the JSON parser to ensure at
                         // run-time that the parser works correctly
-                        t = Target::from_json(t.to_json())?;
+                        t = Target::from_json(t.to_json())
+                            .map_err(LoadTargetError::Other)?;
                         debug!("Got builtin target: {:?}", t);
                         Ok(t)
                     },
                 )+
-                _ => Err(format!("Unable to find target: {}", target))
+                    _ => Err(LoadTargetError::BuiltinTargetNotFound(
+                        format!("Unable to find target: {}", target)))
             }
         }
 
@@ -327,6 +377,7 @@ supported_targets! {
 
     ("aarch64-unknown-freebsd", aarch64_unknown_freebsd),
     ("i686-unknown-freebsd", i686_unknown_freebsd),
+    ("powerpc64-unknown-freebsd", powerpc64_unknown_freebsd),
     ("x86_64-unknown-freebsd", x86_64_unknown_freebsd),
 
     ("i686-unknown-dragonfly", i686_unknown_dragonfly),
@@ -408,12 +459,16 @@ supported_targets! {
 
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
     ("riscv32imac-unknown-none-elf", riscv32imac_unknown_none_elf),
+    ("riscv64imac-unknown-none-elf", riscv64imac_unknown_none_elf),
+    ("riscv64gc-unknown-none-elf", riscv64gc_unknown_none_elf),
 
     ("aarch64-unknown-none", aarch64_unknown_none),
 
     ("x86_64-fortanix-unknown-sgx", x86_64_fortanix_unknown_sgx),
 
     ("x86_64-unknown-uefi", x86_64_unknown_uefi),
+
+    ("nvptx64-nvidia-cuda", nvptx64_nvidia_cuda),
 }
 
 /// Everything `rustc` knows about how to compile for a specific target.
@@ -480,7 +535,7 @@ pub struct TargetOptions {
     pub pre_link_objects_exe_crt: Vec<String>, // ... when linking an executable with a bundled crt
     pub pre_link_objects_dll: Vec<String>, // ... when linking a dylib
     /// Linker arguments that are unconditionally passed after any
-    /// user-defined but before post_link_objects.  Standard platform
+    /// user-defined but before post_link_objects. Standard platform
     /// libraries that should be always be linked to, usually go here.
     pub late_link_args: LinkArgs,
     /// Objects to link after all others, always found within the
@@ -596,7 +651,7 @@ pub struct TargetOptions {
     pub allow_asm: bool,
     /// Whether the target uses a custom unwind resumption routine.
     /// By default LLVM lowers `resume` instructions into calls to `_Unwind_Resume`
-    /// defined in libgcc.  If this option is enabled, the target must provide
+    /// defined in libgcc. If this option is enabled, the target must provide
     /// `eh_unwind_resume` lang item.
     pub custom_unwind_resume: bool,
 
@@ -660,7 +715,7 @@ pub struct TargetOptions {
     /// for this target unconditionally.
     pub no_builtins: bool,
 
-    /// Whether to lower 128-bit operations to compiler_builtins calls.  Use if
+    /// Whether to lower 128-bit operations to compiler_builtins calls. Use if
     /// your backend only supports 64-bit and smaller math.
     pub i128_lowering: bool,
 
@@ -690,11 +745,19 @@ pub struct TargetOptions {
 
     /// If set, have the linker export exactly these symbols, instead of using
     /// the usual logic to figure this out from the crate itself.
-    pub override_export_symbols: Option<Vec<String>>
+    pub override_export_symbols: Option<Vec<String>>,
+
+    /// Determines how or whether the MergeFunctions LLVM pass should run for
+    /// this target. Either "disabled", "trampolines", or "aliases".
+    /// The MergeFunctions pass is generally useful, but some targets may need
+    /// to opt out. The default is "aliases".
+    ///
+    /// Workaround for: https://github.com/rust-lang/rust/issues/57356
+    pub merge_functions: MergeFunctions
 }
 
 impl Default for TargetOptions {
-    /// Create a set of "sane defaults" for any target. This is still
+    /// Creates a set of "sane defaults" for any target. This is still
     /// incomplete, and if used for compilation, will certainly not work.
     fn default() -> TargetOptions {
         TargetOptions {
@@ -773,6 +836,7 @@ impl Default for TargetOptions {
             requires_uwtable: false,
             simd_types_indirect: true,
             override_export_symbols: None,
+            merge_functions: MergeFunctions::Aliases,
         }
     }
 }
@@ -818,7 +882,7 @@ impl Target {
         abi.generic() || !self.options.abi_blacklist.contains(&abi)
     }
 
-    /// Load a target descriptor from a JSON object.
+    /// Loads a target descriptor from a JSON object.
     pub fn from_json(obj: Json) -> TargetResult {
         // While ugly, this code must remain this way to retain
         // compatibility with existing JSON fields and the internal
@@ -875,6 +939,19 @@ impl Target {
                     .map(|o| o.as_u64()
                          .map(|s| base.options.$key_name = Some(s)));
             } );
+            ($key_name:ident, MergeFunctions) => ( {
+                let name = (stringify!($key_name)).replace("_", "-");
+                obj.find(&name[..]).and_then(|o| o.as_string().and_then(|s| {
+                    match s.parse::<MergeFunctions>() {
+                        Ok(mergefunc) => base.options.$key_name = mergefunc,
+                        _ => return Some(Err(format!("'{}' is not a valid value for \
+                                                      merge-functions. Use 'disabled', \
+                                                      'trampolines', or 'aliases'.",
+                                                      s))),
+                    }
+                    Some(Ok(()))
+                })).unwrap_or(Ok(()))
+            } );
             ($key_name:ident, PanicStrategy) => ( {
                 let name = (stringify!($key_name)).replace("_", "-");
                 obj.find(&name[..]).and_then(|o| o.as_string().and_then(|s| {
@@ -1064,6 +1141,7 @@ impl Target {
         key!(requires_uwtable, bool);
         key!(simd_types_indirect, bool);
         key!(override_export_symbols, opt_list);
+        key!(merge_functions, MergeFunctions)?;
 
         if let Some(array) = obj.find("abi-blacklist").and_then(Json::as_array) {
             for name in array.iter().filter_map(|abi| abi.as_string()) {
@@ -1106,8 +1184,10 @@ impl Target {
         match *target_triple {
             TargetTriple::TargetTriple(ref target_triple) => {
                 // check if triple is in list of supported targets
-                if let Ok(t) = load_specific(target_triple) {
-                    return Ok(t)
+                match load_specific(target_triple) {
+                    Ok(t) => return Ok(t),
+                    Err(LoadTargetError::BuiltinTargetNotFound(_)) => (),
+                    Err(LoadTargetError::Other(e)) => return Err(e),
                 }
 
                 // search for a file named `target_triple`.json in RUST_TARGET_PATH
@@ -1275,6 +1355,7 @@ impl ToJson for Target {
         target_option_val!(requires_uwtable);
         target_option_val!(simd_types_indirect);
         target_option_val!(override_export_symbols);
+        target_option_val!(merge_functions);
 
         if default.abi_blacklist != self.options.abi_blacklist {
             d.insert("abi-blacklist".to_string(), self.options.abi_blacklist.iter()
@@ -1339,7 +1420,7 @@ impl TargetTriple {
 }
 
 impl fmt::Display for TargetTriple {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.debug_triple())
     }
 }
diff --git a/src/librustc_target/spec/msp430_none_elf.rs b/src/librustc_target/spec/msp430_none_elf.rs
index df564bc924baf..90af5898089b8 100644
--- a/src/librustc_target/spec/msp430_none_elf.rs
+++ b/src/librustc_target/spec/msp430_none_elf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, PanicStrategy, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/netbsd_base.rs b/src/librustc_target/spec/netbsd_base.rs
index b88d360dd3785..e9cd98c0e7151 100644
--- a/src/librustc_target/spec/netbsd_base.rs
+++ b/src/librustc_target/spec/netbsd_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/nvptx64_nvidia_cuda.rs b/src/librustc_target/spec/nvptx64_nvidia_cuda.rs
new file mode 100644
index 0000000000000..db9d6a7409ee5
--- /dev/null
+++ b/src/librustc_target/spec/nvptx64_nvidia_cuda.rs
@@ -0,0 +1,73 @@
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult, PanicStrategy, MergeFunctions};
+use crate::spec::abi::Abi;
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        arch: "nvptx64".to_string(),
+        data_layout: "e-i64:64-i128:128-v16:16-v32:32-n16:32:64".to_string(),
+        llvm_target: "nvptx64-nvidia-cuda".to_string(),
+
+        target_os: "cuda".to_string(),
+        target_vendor: "nvidia".to_string(),
+        target_env: String::new(),
+
+        linker_flavor: LinkerFlavor::PtxLinker,
+
+        target_endian: "little".to_string(),
+        target_pointer_width: "64".to_string(),
+        target_c_int_width: "32".to_string(),
+
+        options: TargetOptions {
+            // The linker can be installed from `crates.io`.
+            linker: Some("rust-ptx-linker".to_string()),
+
+            // With `ptx-linker` approach, it can be later overriden via link flags.
+            cpu: "sm_30".to_string(),
+
+            // FIXME: create tests for the atomics.
+            max_atomic_width: Some(64),
+
+            // Unwinding on CUDA is neither feasible nor useful.
+            panic_strategy: PanicStrategy::Abort,
+
+            // Needed to use `dylib` and `bin` crate types and the linker.
+            dynamic_linking: true,
+            executables: true,
+
+            // Avoid using dylib because it contain metadata not supported
+            // by LLVM NVPTX backend.
+            only_cdylib: true,
+
+            // Let the `ptx-linker` to handle LLVM lowering into MC / assembly.
+            obj_is_bitcode: true,
+
+            // Convinient and predicable naming scheme.
+            dll_prefix: "".to_string(),
+            dll_suffix: ".ptx".to_string(),
+            exe_suffix: ".ptx".to_string(),
+
+            // Disable MergeFunctions LLVM optimisation pass because it can
+            // produce kernel functions that call other kernel functions.
+            // This behavior is not supported by PTX ISA.
+            merge_functions: MergeFunctions::Disabled,
+
+            // FIXME: enable compilation tests for the target and
+            // create the tests for this.
+            abi_blacklist: vec![
+                Abi::Cdecl,
+                Abi::Stdcall,
+                Abi::Fastcall,
+                Abi::Vectorcall,
+                Abi::Thiscall,
+                Abi::Aapcs,
+                Abi::Win64,
+                Abi::SysV64,
+                Abi::Msp430Interrupt,
+                Abi::X86Interrupt,
+                Abi::AmdGpuKernel,
+            ],
+
+            .. Default::default()
+        },
+    })
+}
diff --git a/src/librustc_target/spec/openbsd_base.rs b/src/librustc_target/spec/openbsd_base.rs
index 4bdf73fc92213..5bcfd62d75bd4 100644
--- a/src/librustc_target/spec/openbsd_base.rs
+++ b/src/librustc_target/spec/openbsd_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions, RelroLevel};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/powerpc64_unknown_freebsd.rs b/src/librustc_target/spec/powerpc64_unknown_freebsd.rs
new file mode 100644
index 0000000000000..360876b9ff557
--- /dev/null
+++ b/src/librustc_target/spec/powerpc64_unknown_freebsd.rs
@@ -0,0 +1,22 @@
+use crate::spec::{LinkerFlavor, Target, TargetResult};
+
+pub fn target() -> TargetResult {
+    let mut base = super::freebsd_base::opts();
+    base.cpu = "ppc64".to_string();
+    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.max_atomic_width = Some(64);
+
+    Ok(Target {
+        llvm_target: "powerpc64-unknown-freebsd".to_string(),
+        target_endian: "big".to_string(),
+        target_pointer_width: "64".to_string(),
+        target_c_int_width: "32".to_string(),
+        data_layout: "E-m:e-i64:64-n32:64".to_string(),
+        arch: "powerpc64".to_string(),
+        target_os: "freebsd".to_string(),
+        target_env: String::new(),
+        target_vendor: "unknown".to_string(),
+        linker_flavor: LinkerFlavor::Gcc,
+        options: base,
+    })
+}
diff --git a/src/librustc_target/spec/powerpc64_unknown_linux_gnu.rs b/src/librustc_target/spec/powerpc64_unknown_linux_gnu.rs
index 1f7ae933cedd1..c16db7583f32b 100644
--- a/src/librustc_target/spec/powerpc64_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/powerpc64_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult, RelroLevel};
+use crate::spec::{LinkerFlavor, Target, TargetResult, RelroLevel};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/powerpc64_unknown_linux_musl.rs b/src/librustc_target/spec/powerpc64_unknown_linux_musl.rs
index 6fc8be8a5c4d8..ac0b7431f91a4 100644
--- a/src/librustc_target/spec/powerpc64_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/powerpc64_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/powerpc64le_unknown_linux_gnu.rs b/src/librustc_target/spec/powerpc64le_unknown_linux_gnu.rs
index 21791a75d2a29..038b925a28692 100644
--- a/src/librustc_target/spec/powerpc64le_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/powerpc64le_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/powerpc64le_unknown_linux_musl.rs b/src/librustc_target/spec/powerpc64le_unknown_linux_musl.rs
index 38f7fe887f5a9..57103345f0a0c 100644
--- a/src/librustc_target/spec/powerpc64le_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/powerpc64le_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/powerpc_unknown_linux_gnu.rs b/src/librustc_target/spec/powerpc_unknown_linux_gnu.rs
index 286d177c864e4..38a801d5ab507 100644
--- a/src/librustc_target/spec/powerpc_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/powerpc_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/powerpc_unknown_linux_gnuspe.rs b/src/librustc_target/spec/powerpc_unknown_linux_gnuspe.rs
index ae144af047232..675b2c749d648 100644
--- a/src/librustc_target/spec/powerpc_unknown_linux_gnuspe.rs
+++ b/src/librustc_target/spec/powerpc_unknown_linux_gnuspe.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/powerpc_unknown_linux_musl.rs b/src/librustc_target/spec/powerpc_unknown_linux_musl.rs
index 3b61889163b4c..240443aa98db4 100644
--- a/src/librustc_target/spec/powerpc_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/powerpc_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/powerpc_unknown_netbsd.rs b/src/librustc_target/spec/powerpc_unknown_netbsd.rs
index e8662a7851907..10e7089cf1c4c 100644
--- a/src/librustc_target/spec/powerpc_unknown_netbsd.rs
+++ b/src/librustc_target/spec/powerpc_unknown_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/redox_base.rs b/src/librustc_target/spec/redox_base.rs
index dd32f02e34049..dc51aeb58391f 100644
--- a/src/librustc_target/spec/redox_base.rs
+++ b/src/librustc_target/spec/redox_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/riscv32imac_unknown_none_elf.rs b/src/librustc_target/spec/riscv32imac_unknown_none_elf.rs
index 5e24f1f1aa2be..5064393d31135 100644
--- a/src/librustc_target/spec/riscv32imac_unknown_none_elf.rs
+++ b/src/librustc_target/spec/riscv32imac_unknown_none_elf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy,
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy,
            Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
@@ -18,7 +18,7 @@ pub fn target() -> TargetResult {
             linker: Some("rust-lld".to_string()),
             cpu: "generic-rv32".to_string(),
             max_atomic_width: Some(32),
-            atomic_cas: false, // incomplete +a extension
+            atomic_cas: true,
             features: "+m,+a,+c".to_string(),
             executables: true,
             panic_strategy: PanicStrategy::Abort,
diff --git a/src/librustc_target/spec/riscv32imc_unknown_none_elf.rs b/src/librustc_target/spec/riscv32imc_unknown_none_elf.rs
index 5d8157ee59a0a..31e74c5920cf9 100644
--- a/src/librustc_target/spec/riscv32imc_unknown_none_elf.rs
+++ b/src/librustc_target/spec/riscv32imc_unknown_none_elf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, LldFlavor, PanicStrategy,
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy,
            Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/riscv64gc_unknown_none_elf.rs b/src/librustc_target/spec/riscv64gc_unknown_none_elf.rs
new file mode 100644
index 0000000000000..2d4070c786fed
--- /dev/null
+++ b/src/librustc_target/spec/riscv64gc_unknown_none_elf.rs
@@ -0,0 +1,31 @@
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy,
+           Target, TargetOptions, TargetResult};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".to_string(),
+        llvm_target: "riscv64".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "64".to_string(),
+        target_c_int_width: "32".to_string(),
+        target_os: "none".to_string(),
+        target_env: String::new(),
+        target_vendor: "unknown".to_string(),
+        arch: "riscv64".to_string(),
+        linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
+
+        options: TargetOptions {
+            linker: Some("rust-lld".to_string()),
+            cpu: "generic-rv64".to_string(),
+            max_atomic_width: Some(64),
+            atomic_cas: true,
+            features: "+m,+a,+f,+d,+c".to_string(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: "static".to_string(),
+            emit_debug_gdb_scripts: false,
+            abi_blacklist: super::riscv_base::abi_blacklist(),
+            .. Default::default()
+        },
+    })
+}
diff --git a/src/librustc_target/spec/riscv64imac_unknown_none_elf.rs b/src/librustc_target/spec/riscv64imac_unknown_none_elf.rs
new file mode 100644
index 0000000000000..f2e152c741e02
--- /dev/null
+++ b/src/librustc_target/spec/riscv64imac_unknown_none_elf.rs
@@ -0,0 +1,31 @@
+use crate::spec::{LinkerFlavor, LldFlavor, PanicStrategy,
+           Target, TargetOptions, TargetResult};
+
+pub fn target() -> TargetResult {
+    Ok(Target {
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".to_string(),
+        llvm_target: "riscv64".to_string(),
+        target_endian: "little".to_string(),
+        target_pointer_width: "64".to_string(),
+        target_c_int_width: "32".to_string(),
+        target_os: "none".to_string(),
+        target_env: String::new(),
+        target_vendor: "unknown".to_string(),
+        arch: "riscv64".to_string(),
+        linker_flavor: LinkerFlavor::Lld(LldFlavor::Ld),
+
+        options: TargetOptions {
+            linker: Some("rust-lld".to_string()),
+            cpu: "generic-rv64".to_string(),
+            max_atomic_width: Some(64),
+            atomic_cas: true,
+            features: "+m,+a,+c".to_string(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: "static".to_string(),
+            emit_debug_gdb_scripts: false,
+            abi_blacklist: super::riscv_base::abi_blacklist(),
+            .. Default::default()
+        },
+    })
+}
diff --git a/src/librustc_target/spec/riscv_base.rs b/src/librustc_target/spec/riscv_base.rs
index ea7fdc39a9a96..ec1dc9b4918bd 100644
--- a/src/librustc_target/spec/riscv_base.rs
+++ b/src/librustc_target/spec/riscv_base.rs
@@ -1,4 +1,4 @@
-use spec::abi::Abi;
+use crate::spec::abi::Abi;
 
 // All the calling conventions trigger an assertion(Unsupported calling
 // convention) in llvm on RISCV
diff --git a/src/librustc_target/spec/s390x_unknown_linux_gnu.rs b/src/librustc_target/spec/s390x_unknown_linux_gnu.rs
index c18c94511f8d7..f259787e1d54d 100644
--- a/src/librustc_target/spec/s390x_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/s390x_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/solaris_base.rs b/src/librustc_target/spec/solaris_base.rs
index f5f8509210570..0dfbb13b77317 100644
--- a/src/librustc_target/spec/solaris_base.rs
+++ b/src/librustc_target/spec/solaris_base.rs
@@ -1,4 +1,4 @@
-use spec::TargetOptions;
+use crate::spec::TargetOptions;
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/sparc64_unknown_linux_gnu.rs b/src/librustc_target/spec/sparc64_unknown_linux_gnu.rs
index e5e3752be7f82..c842b22d4e16e 100644
--- a/src/librustc_target/spec/sparc64_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/sparc64_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/sparc64_unknown_netbsd.rs b/src/librustc_target/spec/sparc64_unknown_netbsd.rs
index 62efd41dbb8ee..78d53e69e8b52 100644
--- a/src/librustc_target/spec/sparc64_unknown_netbsd.rs
+++ b/src/librustc_target/spec/sparc64_unknown_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/sparc_unknown_linux_gnu.rs b/src/librustc_target/spec/sparc_unknown_linux_gnu.rs
index b6468993790d8..162cd311a3826 100644
--- a/src/librustc_target/spec/sparc_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/sparc_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/sparcv9_sun_solaris.rs b/src/librustc_target/spec/sparcv9_sun_solaris.rs
index f1c5c5ac44f1a..acc03fd0d79ee 100644
--- a/src/librustc_target/spec/sparcv9_sun_solaris.rs
+++ b/src/librustc_target/spec/sparcv9_sun_solaris.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::solaris_base::opts();
diff --git a/src/librustc_target/spec/thumb_base.rs b/src/librustc_target/spec/thumb_base.rs
index 06cb6a8d823ef..ed0dbb766a835 100644
--- a/src/librustc_target/spec/thumb_base.rs
+++ b/src/librustc_target/spec/thumb_base.rs
@@ -28,7 +28,7 @@
 // build scripts / gcc flags.
 
 use std::default::Default;
-use spec::{PanicStrategy, TargetOptions};
+use crate::spec::{PanicStrategy, TargetOptions};
 
 pub fn opts() -> TargetOptions {
     // See rust-lang/rfcs#1645 for a discussion about these defaults
diff --git a/src/librustc_target/spec/thumbv6m_none_eabi.rs b/src/librustc_target/spec/thumbv6m_none_eabi.rs
index 98c46e9c600a3..2ab61b57f6bb6 100644
--- a/src/librustc_target/spec/thumbv6m_none_eabi.rs
+++ b/src/librustc_target/spec/thumbv6m_none_eabi.rs
@@ -1,6 +1,6 @@
 // Targets the Cortex-M0, Cortex-M0+ and Cortex-M1 processors (ARMv6-M architecture)
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs b/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
index eaa08fadbc0f3..310fac31c0c5b 100644
--- a/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/thumbv7a_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult, PanicStrategy};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult, PanicStrategy};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
diff --git a/src/librustc_target/spec/thumbv7em_none_eabi.rs b/src/librustc_target/spec/thumbv7em_none_eabi.rs
index 8a1fe09cdb07a..97114c342cdc7 100644
--- a/src/librustc_target/spec/thumbv7em_none_eabi.rs
+++ b/src/librustc_target/spec/thumbv7em_none_eabi.rs
@@ -9,7 +9,7 @@
 // To opt-in to hardware accelerated floating point operations, you can use, for example,
 // `-C target-feature=+vfp4` or `-C target-cpu=cortex-m4`.
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv7em_none_eabihf.rs b/src/librustc_target/spec/thumbv7em_none_eabihf.rs
index 0c9aa1c5149ff..e4358bdd7991e 100644
--- a/src/librustc_target/spec/thumbv7em_none_eabihf.rs
+++ b/src/librustc_target/spec/thumbv7em_none_eabihf.rs
@@ -8,7 +8,7 @@
 //
 // To opt into double precision hardware support, use the `-C target-feature=-fp-only-sp` flag.
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv7m_none_eabi.rs b/src/librustc_target/spec/thumbv7m_none_eabi.rs
index 9bff3473c58af..daf25b16d58d6 100644
--- a/src/librustc_target/spec/thumbv7m_none_eabi.rs
+++ b/src/librustc_target/spec/thumbv7m_none_eabi.rs
@@ -1,6 +1,6 @@
 // Targets the Cortex-M3 processor (ARMv7-M)
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv7neon_linux_androideabi.rs b/src/librustc_target/spec/thumbv7neon_linux_androideabi.rs
index 2d92e29c09d96..e248b930e6e4c 100644
--- a/src/librustc_target/spec/thumbv7neon_linux_androideabi.rs
+++ b/src/librustc_target/spec/thumbv7neon_linux_androideabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // This target if is for the Android v7a ABI in thumb mode with
 // NEON unconditionally enabled and, therefore, with 32 FPU registers
diff --git a/src/librustc_target/spec/thumbv7neon_unknown_linux_gnueabihf.rs b/src/librustc_target/spec/thumbv7neon_unknown_linux_gnueabihf.rs
index bdf57969154c0..bef62b0a2ebe6 100644
--- a/src/librustc_target/spec/thumbv7neon_unknown_linux_gnueabihf.rs
+++ b/src/librustc_target/spec/thumbv7neon_unknown_linux_gnueabihf.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 
 // This target is for glibc Linux on ARMv7 with thumb mode enabled
 // (for consistency with Android and Debian-based distributions)
diff --git a/src/librustc_target/spec/thumbv8m_base_none_eabi.rs b/src/librustc_target/spec/thumbv8m_base_none_eabi.rs
index 0e0e73efd45cc..be8a476db4dbc 100644
--- a/src/librustc_target/spec/thumbv8m_base_none_eabi.rs
+++ b/src/librustc_target/spec/thumbv8m_base_none_eabi.rs
@@ -1,6 +1,6 @@
 // Targets the Cortex-M23 processor (Baseline ARMv8-M)
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv8m_main_none_eabi.rs b/src/librustc_target/spec/thumbv8m_main_none_eabi.rs
index dc2454d749780..49ab643d484bc 100644
--- a/src/librustc_target/spec/thumbv8m_main_none_eabi.rs
+++ b/src/librustc_target/spec/thumbv8m_main_none_eabi.rs
@@ -1,7 +1,7 @@
 // Targets the Cortex-M33 processor (Armv8-M Mainline architecture profile),
 // without the Floating Point extension.
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/thumbv8m_main_none_eabihf.rs b/src/librustc_target/spec/thumbv8m_main_none_eabihf.rs
index 5fa1f42288d1a..6a3d8e61d7fe8 100644
--- a/src/librustc_target/spec/thumbv8m_main_none_eabihf.rs
+++ b/src/librustc_target/spec/thumbv8m_main_none_eabihf.rs
@@ -1,7 +1,7 @@
 // Targets the Cortex-M33 processor (Armv8-M Mainline architecture profile),
 // with the Floating Point extension.
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetOptions, TargetResult};
 
 pub fn target() -> TargetResult {
     Ok(Target {
diff --git a/src/librustc_target/spec/uefi_base.rs b/src/librustc_target/spec/uefi_base.rs
index 4628089ffe1f4..631966c09a498 100644
--- a/src/librustc_target/spec/uefi_base.rs
+++ b/src/librustc_target/spec/uefi_base.rs
@@ -5,11 +5,11 @@
 // UEFI uses COFF/PE32+ format for binaries. All binaries must be statically linked. No dynamic
 // linker is supported. As native to COFF, binaries are position-dependent, but will be relocated
 // by the loader if the pre-chosen memory location is already in use.
-// UEFI forbids running code on anything but the boot-CPU. Not interrupts are allowed other than
+// UEFI forbids running code on anything but the boot-CPU. No interrupts are allowed other than
 // the timer-interrupt. Device-drivers are required to use polling-based models. Furthermore, all
 // code runs in the same environment, no process separation is supported.
 
-use spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, LldFlavor, PanicStrategy, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
@@ -21,7 +21,10 @@ pub fn opts() -> TargetOptions {
             "/NOLOGO".to_string(),
 
             // UEFI is fully compatible to non-executable data pages. Tell the compiler that
-            // non-code sections can be marked as non-executable, including stack pages.
+            // non-code sections can be marked as non-executable, including stack pages. In fact,
+            // firmware might enforce this, so we better let the linker know about this, so it
+            // will fail if the compiler ever tries placing code on the stack (e.g., trampoline
+            // constructs and alike).
             "/NXCOMPAT".to_string(),
 
             // There is no runtime for UEFI targets, prevent them from being linked. UEFI targets
diff --git a/src/librustc_target/spec/windows_base.rs b/src/librustc_target/spec/windows_base.rs
index 65d618232a249..38db9cd356cd8 100644
--- a/src/librustc_target/spec/windows_base.rs
+++ b/src/librustc_target/spec/windows_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/windows_msvc_base.rs b/src/librustc_target/spec/windows_msvc_base.rs
index 89f6b1bcc71c5..fdd747cdb865a 100644
--- a/src/librustc_target/spec/windows_msvc_base.rs
+++ b/src/librustc_target/spec/windows_msvc_base.rs
@@ -1,4 +1,4 @@
-use spec::{LinkArgs, LinkerFlavor, TargetOptions};
+use crate::spec::{LinkArgs, LinkerFlavor, TargetOptions};
 use std::default::Default;
 
 pub fn opts() -> TargetOptions {
diff --git a/src/librustc_target/spec/x86_64_apple_darwin.rs b/src/librustc_target/spec/x86_64_apple_darwin.rs
index 7de33fe8ac52a..0911ce06c13d7 100644
--- a/src/librustc_target/spec/x86_64_apple_darwin.rs
+++ b/src/librustc_target/spec/x86_64_apple_darwin.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::apple_base::opts();
diff --git a/src/librustc_target/spec/x86_64_apple_ios.rs b/src/librustc_target/spec/x86_64_apple_ios.rs
index 286a73d48048c..1f9594b906282 100644
--- a/src/librustc_target/spec/x86_64_apple_ios.rs
+++ b/src/librustc_target/spec/x86_64_apple_ios.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetOptions, TargetResult};
 use super::apple_ios_base::{opts, Arch};
 
 pub fn target() -> TargetResult {
diff --git a/src/librustc_target/spec/x86_64_fuchsia.rs b/src/librustc_target/spec/x86_64_fuchsia.rs
index 00fb7066ca28f..a24d432c591d2 100644
--- a/src/librustc_target/spec/x86_64_fuchsia.rs
+++ b/src/librustc_target/spec/x86_64_fuchsia.rs
@@ -1,4 +1,4 @@
-use spec::{LldFlavor, LinkerFlavor, Target, TargetResult};
+use crate::spec::{LldFlavor, LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::fuchsia_base::opts();
diff --git a/src/librustc_target/spec/x86_64_linux_android.rs b/src/librustc_target/spec/x86_64_linux_android.rs
index 29d5dfa5790a1..c3c6c7bf56fef 100644
--- a/src/librustc_target/spec/x86_64_linux_android.rs
+++ b/src/librustc_target/spec/x86_64_linux_android.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::android_base::opts();
diff --git a/src/librustc_target/spec/x86_64_pc_windows_gnu.rs b/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
index c3c36d22cef5e..35e0d55cd045e 100644
--- a/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
+++ b/src/librustc_target/spec/x86_64_pc_windows_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_base::opts();
diff --git a/src/librustc_target/spec/x86_64_pc_windows_msvc.rs b/src/librustc_target/spec/x86_64_pc_windows_msvc.rs
index 178d67784e653..073d49be5a9ab 100644
--- a/src/librustc_target/spec/x86_64_pc_windows_msvc.rs
+++ b/src/librustc_target/spec/x86_64_pc_windows_msvc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::windows_msvc_base::opts();
diff --git a/src/librustc_target/spec/x86_64_rumprun_netbsd.rs b/src/librustc_target/spec/x86_64_rumprun_netbsd.rs
index 37c7925c6985e..a2c706c4c7232 100644
--- a/src/librustc_target/spec/x86_64_rumprun_netbsd.rs
+++ b/src/librustc_target/spec/x86_64_rumprun_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/x86_64_sun_solaris.rs b/src/librustc_target/spec/x86_64_sun_solaris.rs
index 3534f9e6436b4..3bf3f51ae2512 100644
--- a/src/librustc_target/spec/x86_64_sun_solaris.rs
+++ b/src/librustc_target/spec/x86_64_sun_solaris.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::solaris_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_bitrig.rs b/src/librustc_target/spec/x86_64_unknown_bitrig.rs
index fa5392175606a..999d93a7e6090 100644
--- a/src/librustc_target/spec/x86_64_unknown_bitrig.rs
+++ b/src/librustc_target/spec/x86_64_unknown_bitrig.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::bitrig_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_cloudabi.rs b/src/librustc_target/spec/x86_64_unknown_cloudabi.rs
index c1253a3b2727b..d48120c5401c2 100644
--- a/src/librustc_target/spec/x86_64_unknown_cloudabi.rs
+++ b/src/librustc_target/spec/x86_64_unknown_cloudabi.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::cloudabi_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_dragonfly.rs b/src/librustc_target/spec/x86_64_unknown_dragonfly.rs
index 815aa57252561..f55ee6969092b 100644
--- a/src/librustc_target/spec/x86_64_unknown_dragonfly.rs
+++ b/src/librustc_target/spec/x86_64_unknown_dragonfly.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::dragonfly_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_freebsd.rs b/src/librustc_target/spec/x86_64_unknown_freebsd.rs
index 8d43883f33bf3..1d9c5cce3f729 100644
--- a/src/librustc_target/spec/x86_64_unknown_freebsd.rs
+++ b/src/librustc_target/spec/x86_64_unknown_freebsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::freebsd_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_haiku.rs b/src/librustc_target/spec/x86_64_unknown_haiku.rs
index 608354732d9d1..4ab15fa4e90f5 100644
--- a/src/librustc_target/spec/x86_64_unknown_haiku.rs
+++ b/src/librustc_target/spec/x86_64_unknown_haiku.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::haiku_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_hermit.rs b/src/librustc_target/spec/x86_64_unknown_hermit.rs
index de5992cbf5ef2..a696ee16d7c9e 100644
--- a/src/librustc_target/spec/x86_64_unknown_hermit.rs
+++ b/src/librustc_target/spec/x86_64_unknown_hermit.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::hermit_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_l4re_uclibc.rs b/src/librustc_target/spec/x86_64_unknown_l4re_uclibc.rs
index cf04cc1bdc2f5..e5fdb386ef301 100644
--- a/src/librustc_target/spec/x86_64_unknown_l4re_uclibc.rs
+++ b/src/librustc_target/spec/x86_64_unknown_l4re_uclibc.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::l4re_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_linux_gnu.rs b/src/librustc_target/spec/x86_64_unknown_linux_gnu.rs
index c6ec8de5b7312..cb279e86f1498 100644
--- a/src/librustc_target/spec/x86_64_unknown_linux_gnu.rs
+++ b/src/librustc_target/spec/x86_64_unknown_linux_gnu.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs b/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs
index e4dfb8d05cdfa..0b2d7aacc4ddf 100644
--- a/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs
+++ b/src/librustc_target/spec/x86_64_unknown_linux_gnux32.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_linux_musl.rs b/src/librustc_target/spec/x86_64_unknown_linux_musl.rs
index 95321fe2f783e..2e1bc839873c7 100644
--- a/src/librustc_target/spec/x86_64_unknown_linux_musl.rs
+++ b/src/librustc_target/spec/x86_64_unknown_linux_musl.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::linux_musl_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_netbsd.rs b/src/librustc_target/spec/x86_64_unknown_netbsd.rs
index fbd07ecce1afb..ffc4f1d5c49b7 100644
--- a/src/librustc_target/spec/x86_64_unknown_netbsd.rs
+++ b/src/librustc_target/spec/x86_64_unknown_netbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::netbsd_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_openbsd.rs b/src/librustc_target/spec/x86_64_unknown_openbsd.rs
index 68496247b1596..f2abd1071227e 100644
--- a/src/librustc_target/spec/x86_64_unknown_openbsd.rs
+++ b/src/librustc_target/spec/x86_64_unknown_openbsd.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::openbsd_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_redox.rs b/src/librustc_target/spec/x86_64_unknown_redox.rs
index d04bc5cc6ec21..f0a4519f59548 100644
--- a/src/librustc_target/spec/x86_64_unknown_redox.rs
+++ b/src/librustc_target/spec/x86_64_unknown_redox.rs
@@ -1,4 +1,4 @@
-use spec::{LinkerFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::redox_base::opts();
diff --git a/src/librustc_target/spec/x86_64_unknown_uefi.rs b/src/librustc_target/spec/x86_64_unknown_uefi.rs
index 0d7b4fc060bd9..443479f55f04a 100644
--- a/src/librustc_target/spec/x86_64_unknown_uefi.rs
+++ b/src/librustc_target/spec/x86_64_unknown_uefi.rs
@@ -5,20 +5,22 @@
 // The win64 ABI is used. It differs from the sysv64 ABI, so we must use a windows target with
 // LLVM. "x86_64-unknown-windows" is used to get the minimal subset of windows-specific features.
 
-use spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
+use crate::spec::{LinkerFlavor, LldFlavor, Target, TargetResult};
 
 pub fn target() -> TargetResult {
     let mut base = super::uefi_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
 
-    // We disable MMX and SSE for now. UEFI does not prevent these from being used, but there have
-    // been reports to GRUB that some firmware does not initialize the FP exception handlers
-    // properly. Therefore, using FP coprocessors will end you up at random memory locations when
-    // you throw FP exceptions.
-    // To be safe, we disable them for now and force soft-float. This can be revisited when we
-    // have more test coverage. Disabling FP served GRUB well so far, so it should be good for us
-    // as well.
+    // We disable MMX and SSE for now, even though UEFI allows using them. Problem is, you have to
+    // enable these CPU features explicitly before their first use, otherwise their instructions
+    // will trigger an exception. Rust does not inject any code that enables AVX/MMX/SSE
+    // instruction sets, so this must be done by the firmware. However, existing firmware is known
+    // to leave these uninitialized, thus triggering exceptions if we make use of them. Which is
+    // why we avoid them and instead use soft-floats. This is also what GRUB and friends did so
+    // far.
+    // If you initialize FP units yourself, you can override these flags with custom linker
+    // arguments, thus giving you access to full MMX/SSE acceleration.
     base.features = "-mmx,-sse,+soft-float".to_string();
 
     // UEFI systems run without a host OS, hence we cannot assume any code locality. We must tell
@@ -26,9 +28,9 @@ pub fn target() -> TargetResult {
     // places no locality-restrictions, so it fits well here.
     base.code_model = Some("large".to_string());
 
-    // UEFI mostly mirrors the calling-conventions used on windows. In case of x86-64 this means
-    // small structs will be returned as int. This shouldn't matter much, since the restrictions
-    // placed by the UEFI specifications forbid any ABI to return structures.
+    // UEFI mirrors the calling-conventions used on windows. In case of x86-64 this means small
+    // structs will be returned as int. This shouldn't matter much, since the restrictions placed
+    // by the UEFI specifications forbid any ABI to return structures.
     base.abi_return_struct_as_int = true;
 
     Ok(Target {
diff --git a/src/librustc_traits/Cargo.toml b/src/librustc_traits/Cargo.toml
index bf946d39806ec..da19cc95eb95a 100644
--- a/src/librustc_traits/Cargo.toml
+++ b/src/librustc_traits/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_traits"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_traits"
diff --git a/src/librustc_traits/chalk_context/mod.rs b/src/librustc_traits/chalk_context/mod.rs
index 303920b5842c9..a326d84725ab4 100644
--- a/src/librustc_traits/chalk_context/mod.rs
+++ b/src/librustc_traits/chalk_context/mod.rs
@@ -177,7 +177,7 @@ impl context::AggregateOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
 }
 
 impl context::ContextOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
-    /// True if this is a coinductive goal: basically proving that an auto trait
+    /// Returns `true` if this is a coinductive goal: basically proving that an auto trait
     /// is implemented or proving that a trait reference is well-formed.
     fn is_coinductive(
         &self,
@@ -202,7 +202,7 @@ impl context::ContextOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
         }
     }
 
-    /// Create an inference table for processing a new goal and instantiate that goal
+    /// Creates an inference table for processing a new goal and instantiate that goal
     /// in that context, returning "all the pieces".
     ///
     /// More specifically: given a u-canonical goal `arg`, creates a
@@ -211,9 +211,9 @@ impl context::ContextOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
     /// each bound variable in `arg` to a fresh inference variable
     /// from T. Returns:
     ///
-    /// - the table `T`
-    /// - the substitution `S`
-    /// - the environment and goal found by substitution `S` into `arg`
+    /// - the table `T`,
+    /// - the substitution `S`,
+    /// - the environment and goal found by substitution `S` into `arg`.
     fn instantiate_ucanonical_goal<R>(
         &self,
         arg: &Canonical<'gcx, InEnvironment<'gcx, Goal<'gcx>>>,
@@ -241,7 +241,7 @@ impl context::ContextOps<ChalkArenas<'gcx>> for ChalkContext<'cx, 'gcx> {
         })
     }
 
-    /// True if this solution has no region constraints.
+    /// Returns `true` if this solution has no region constraints.
     fn empty_constraints(ccs: &Canonical<'gcx, ConstrainedSubst<'gcx>>) -> bool {
         ccs.value.constraints.is_empty()
     }
@@ -502,13 +502,13 @@ type ChalkHhGoal<'tcx> = HhGoal<ChalkArenas<'tcx>>;
 type ChalkExClause<'tcx> = ExClause<ChalkArenas<'tcx>>;
 
 impl Debug for ChalkContext<'cx, 'gcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "ChalkContext")
     }
 }
 
 impl Debug for ChalkInferenceContext<'cx, 'gcx, 'tcx> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "ChalkInferenceContext")
     }
 }
@@ -658,7 +658,7 @@ impl<'tcx, 'gcx: 'tcx, T> Upcast<'tcx, 'gcx> for Canonical<'gcx, T>
     }
 }
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         evaluate_goal,
         ..*p
diff --git a/src/librustc_traits/chalk_context/program_clauses.rs b/src/librustc_traits/chalk_context/program_clauses.rs
index 71f4945fd648d..adfd26814db1e 100644
--- a/src/librustc_traits/chalk_context/program_clauses.rs
+++ b/src/librustc_traits/chalk_context/program_clauses.rs
@@ -220,7 +220,7 @@ fn wf_clause_for_slice<'tcx>(tcx: ty::TyCtxt<'_, '_, 'tcx>) -> Clauses<'tcx> {
         def_id: sized_trait,
         substs: tcx.mk_substs_trait(ty, ty::List::empty()),
     };
-    let sized_implemented: DomainGoal = ty::TraitPredicate {
+    let sized_implemented: DomainGoal<'_> = ty::TraitPredicate {
         trait_ref: sized_implemented
     }.lower();
 
@@ -252,7 +252,7 @@ fn wf_clause_for_array<'tcx>(
         def_id: sized_trait,
         substs: tcx.mk_substs_trait(ty, ty::List::empty()),
     };
-    let sized_implemented: DomainGoal = ty::TraitPredicate {
+    let sized_implemented: DomainGoal<'_> = ty::TraitPredicate {
         trait_ref: sized_implemented
     }.lower();
 
@@ -326,7 +326,7 @@ fn wf_clause_for_ref<'tcx>(
         mutbl,
     });
 
-    let _outlives: DomainGoal = ty::OutlivesPredicate(ty, region).lower();
+    let _outlives: DomainGoal<'_> = ty::OutlivesPredicate(ty, region).lower();
     let wf_clause = ProgramClause {
         goal: DomainGoal::WellFormed(WellFormed::Ty(ref_ty)),
         hypotheses: ty::List::empty(),
diff --git a/src/librustc_traits/dropck_outlives.rs b/src/librustc_traits/dropck_outlives.rs
index 7979fe4a75073..7185c4ce44640 100644
--- a/src/librustc_traits/dropck_outlives.rs
+++ b/src/librustc_traits/dropck_outlives.rs
@@ -10,7 +10,7 @@ use rustc::util::nodemap::FxHashSet;
 use rustc_data_structures::sync::Lrc;
 use syntax::source_map::{Span, DUMMY_SP};
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         dropck_outlives,
         adt_dtorck_constraint,
@@ -145,7 +145,7 @@ fn dropck_outlives<'tcx>(
     )
 }
 
-/// Return a set of constraints that needs to be satisfied in
+/// Returns a set of constraints that needs to be satisfied in
 /// order for `ty` to be valid for destruction.
 fn dtorck_constraint_for_ty<'a, 'gcx, 'tcx>(
     tcx: TyCtxt<'a, 'gcx, 'tcx>,
@@ -305,7 +305,7 @@ crate fn adt_dtorck_constraint<'a, 'tcx>(
     let mut result = def.all_fields()
         .map(|field| tcx.type_of(field.did))
         .map(|fty| dtorck_constraint_for_ty(tcx, span, fty, 0, fty))
-        .collect::<Result<DtorckConstraint, NoSolution>>()?;
+        .collect::<Result<DtorckConstraint<'_>, NoSolution>>()?;
     result.outlives.extend(tcx.destructor_constraints(def));
     dedup_dtorck_constraint(&mut result);
 
diff --git a/src/librustc_traits/evaluate_obligation.rs b/src/librustc_traits/evaluate_obligation.rs
index c5b6de2793552..83aebd16e2400 100644
--- a/src/librustc_traits/evaluate_obligation.rs
+++ b/src/librustc_traits/evaluate_obligation.rs
@@ -6,7 +6,7 @@ use rustc::ty::query::Providers;
 use rustc::ty::{ParamEnvAnd, TyCtxt};
 use syntax::source_map::DUMMY_SP;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         evaluate_obligation,
         ..*p
diff --git a/src/librustc_traits/implied_outlives_bounds.rs b/src/librustc_traits/implied_outlives_bounds.rs
index a3fb96990545e..dad45130062a4 100644
--- a/src/librustc_traits/implied_outlives_bounds.rs
+++ b/src/librustc_traits/implied_outlives_bounds.rs
@@ -1,6 +1,7 @@
 //! Provider for the `implied_outlives_bounds` query.
 //! Do not call this query directory. See [`rustc::traits::query::implied_outlives_bounds`].
 
+use rustc::hir;
 use rustc::infer::InferCtxt;
 use rustc::infer::canonical::{self, Canonical};
 use rustc::traits::{TraitEngine, TraitEngineExt};
@@ -11,13 +12,12 @@ use rustc::ty::outlives::Component;
 use rustc::ty::query::Providers;
 use rustc::ty::wf;
 use smallvec::{SmallVec, smallvec};
-use syntax::ast::DUMMY_NODE_ID;
 use syntax::source_map::DUMMY_SP;
 use rustc::traits::FulfillmentContext;
 
 use rustc_data_structures::sync::Lrc;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         implied_outlives_bounds,
         ..*p
@@ -65,7 +65,7 @@ fn compute_implied_outlives_bounds<'tcx>(
         // unresolved inference variables here anyway, but there might be
         // during typeck under some circumstances.)
         let obligations =
-            wf::obligations(infcx, param_env, DUMMY_NODE_ID, ty, DUMMY_SP).unwrap_or(vec![]);
+            wf::obligations(infcx, param_env, hir::DUMMY_HIR_ID, ty, DUMMY_SP).unwrap_or(vec![]);
 
         // N.B., all of these predicates *ought* to be easily proven
         // true. In fact, their correctness is (mostly) implied by
diff --git a/src/librustc_traits/lib.rs b/src/librustc_traits/lib.rs
index a220b92191369..d52a976981db0 100644
--- a/src/librustc_traits/lib.rs
+++ b/src/librustc_traits/lib.rs
@@ -1,22 +1,18 @@
 //! New recursive solver modeled on Chalk's recursive solver. Most of
 //! the guts are broken up into modules; see the comments in those modules.
 
+#![deny(rust_2018_idioms)]
+
 #![feature(crate_visibility_modifier)]
 #![feature(in_band_lifetimes)]
 #![feature(nll)]
 
 #![recursion_limit="256"]
 
-extern crate chalk_engine;
 #[macro_use]
 extern crate log;
 #[macro_use]
 extern crate rustc;
-extern crate rustc_data_structures;
-extern crate rustc_target;
-extern crate syntax;
-extern crate syntax_pos;
-extern crate smallvec;
 
 mod chalk_context;
 mod dropck_outlives;
@@ -30,7 +26,7 @@ mod type_op;
 
 use rustc::ty::query::Providers;
 
-pub fn provide(p: &mut Providers) {
+pub fn provide(p: &mut Providers<'_>) {
     dropck_outlives::provide(p);
     evaluate_obligation::provide(p);
     implied_outlives_bounds::provide(p);
diff --git a/src/librustc_traits/lowering/mod.rs b/src/librustc_traits/lowering/mod.rs
index 5502a1d186eee..908fdcfe7430f 100644
--- a/src/librustc_traits/lowering/mod.rs
+++ b/src/librustc_traits/lowering/mod.rs
@@ -23,7 +23,7 @@ use syntax::ast;
 
 use std::iter;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         program_clauses_for,
         program_clauses_for_env: environment::program_clauses_for_env,
@@ -158,7 +158,8 @@ crate fn program_clauses_for<'a, 'tcx>(
     def_id: DefId,
 ) -> Clauses<'tcx> {
     match tcx.def_key(def_id).disambiguated_data.data {
-        DefPathData::Trait(_) => program_clauses_for_trait(tcx, def_id),
+        DefPathData::Trait(_) |
+        DefPathData::TraitAlias(_) => program_clauses_for_trait(tcx, def_id),
         DefPathData::Impl => program_clauses_for_impl(tcx, def_id),
         DefPathData::AssocTypeInImpl(..) => program_clauses_for_associated_type_value(tcx, def_id),
         DefPathData::AssocTypeInTrait(..) => program_clauses_for_associated_type_def(tcx, def_id),
@@ -192,7 +193,7 @@ fn program_clauses_for_trait<'a, 'tcx>(
     };
 
     // `Implemented(Self: Trait<P1..Pn>)`
-    let impl_trait: DomainGoal = trait_pred.lower();
+    let impl_trait: DomainGoal<'_> = trait_pred.lower();
 
     // `FromEnv(Self: Trait<P1..Pn>)`
     let from_env_goal = tcx.mk_goal(impl_trait.into_from_env_goal().into_goal());
@@ -574,7 +575,7 @@ pub fn program_clauses_for_associated_type_value<'a, 'tcx>(
     let ty = tcx.type_of(item_id);
 
     // `Implemented(A0: Trait<A1..An>)`
-    let trait_implemented: DomainGoal = ty::TraitPredicate { trait_ref }.lower();
+    let trait_implemented: DomainGoal<'_> = ty::TraitPredicate { trait_ref }.lower();
 
     // `<A0 as Trait<A1..An>>::AssocType<Pn+1..Pm>`
     let projection_ty = ty::ProjectionTy::from_ref_and_name(tcx, trait_ref, item.ident);
diff --git a/src/librustc_traits/normalize_erasing_regions.rs b/src/librustc_traits/normalize_erasing_regions.rs
index c06cdbd0928da..412d2ca6dfcff 100644
--- a/src/librustc_traits/normalize_erasing_regions.rs
+++ b/src/librustc_traits/normalize_erasing_regions.rs
@@ -4,7 +4,7 @@ use rustc::ty::query::Providers;
 use rustc::ty::{self, ParamEnvAnd, Ty, TyCtxt};
 use std::sync::atomic::Ordering;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         normalize_ty_after_erasing_regions,
         ..*p
diff --git a/src/librustc_traits/normalize_projection_ty.rs b/src/librustc_traits/normalize_projection_ty.rs
index b31e9c15d0367..38f7a21e66c55 100644
--- a/src/librustc_traits/normalize_projection_ty.rs
+++ b/src/librustc_traits/normalize_projection_ty.rs
@@ -1,3 +1,4 @@
+use rustc::hir;
 use rustc::infer::canonical::{Canonical, QueryResponse};
 use rustc::traits::query::{normalize::NormalizationResult, CanonicalProjectionGoal, NoSolution};
 use rustc::traits::{self, ObligationCause, SelectionContext, TraitEngineExt};
@@ -5,10 +6,9 @@ use rustc::ty::query::Providers;
 use rustc::ty::{ParamEnvAnd, TyCtxt};
 use rustc_data_structures::sync::Lrc;
 use std::sync::atomic::Ordering;
-use syntax::ast::DUMMY_NODE_ID;
 use syntax_pos::DUMMY_SP;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         normalize_projection_ty,
         ..*p
@@ -34,7 +34,7 @@ fn normalize_projection_ty<'tcx>(
              value: goal,
          }| {
             let selcx = &mut SelectionContext::new(infcx);
-            let cause = ObligationCause::misc(DUMMY_SP, DUMMY_NODE_ID);
+            let cause = ObligationCause::misc(DUMMY_SP, hir::DUMMY_HIR_ID);
             let mut obligations = vec![];
             let answer = traits::normalize_projection_type(
                 selcx,
diff --git a/src/librustc_traits/type_op.rs b/src/librustc_traits/type_op.rs
index 52fcb5b80f4ae..30fbdbdeb4433 100644
--- a/src/librustc_traits/type_op.rs
+++ b/src/librustc_traits/type_op.rs
@@ -1,9 +1,8 @@
 use rustc::infer::at::ToTrace;
 use rustc::infer::canonical::{Canonical, QueryResponse};
 use rustc::infer::InferCtxt;
+use rustc::hir;
 use rustc::hir::def_id::DefId;
-use rustc::mir::ProjectionKind;
-use rustc::mir::tcx::PlaceTy;
 use rustc::traits::query::type_op::ascribe_user_type::AscribeUserType;
 use rustc::traits::query::type_op::eq::Eq;
 use rustc::traits::query::type_op::normalize::Normalize;
@@ -20,10 +19,9 @@ use rustc::ty::{
 };
 use rustc_data_structures::sync::Lrc;
 use std::fmt;
-use syntax::ast;
 use syntax_pos::DUMMY_SP;
 
-crate fn provide(p: &mut Providers) {
+crate fn provide(p: &mut Providers<'_>) {
     *p = Providers {
         type_op_ascribe_user_type,
         type_op_eq,
@@ -44,17 +42,16 @@ fn type_op_ascribe_user_type<'tcx>(
     tcx.infer_ctxt()
         .enter_canonical_trait_query(&canonicalized, |infcx, fulfill_cx, key| {
             let (
-                param_env, AscribeUserType { mir_ty, variance, def_id, user_substs, projs }
+                param_env, AscribeUserType { mir_ty, def_id, user_substs }
             ) = key.into_parts();
 
             debug!(
-                "type_op_ascribe_user_type: mir_ty={:?} variance={:?} def_id={:?} \
-                 user_substs={:?} projs={:?}",
-                mir_ty, variance, def_id, user_substs, projs
+                "type_op_ascribe_user_type: mir_ty={:?} def_id={:?} user_substs={:?}",
+                mir_ty, def_id, user_substs
             );
 
             let mut cx = AscribeUserTypeCx { infcx, param_env, fulfill_cx };
-            cx.relate_mir_and_user_ty(mir_ty, variance, def_id, user_substs, projs)?;
+            cx.relate_mir_and_user_ty(mir_ty, def_id, user_substs)?;
 
             Ok(())
         })
@@ -74,7 +71,7 @@ impl AscribeUserTypeCx<'me, 'gcx, 'tcx> {
         self.infcx
             .partially_normalize_associated_types_in(
                 DUMMY_SP,
-                ast::CRATE_NODE_ID,
+                hir::CRATE_HIR_ID,
                 self.param_env,
                 &value,
             )
@@ -112,10 +109,8 @@ impl AscribeUserTypeCx<'me, 'gcx, 'tcx> {
     fn relate_mir_and_user_ty(
         &mut self,
         mir_ty: Ty<'tcx>,
-        variance: Variance,
         def_id: DefId,
         user_substs: UserSubsts<'tcx>,
-        projs: &[ProjectionKind<'tcx>],
     ) -> Result<(), NoSolution> {
         let UserSubsts {
             user_self_ty,
@@ -128,35 +123,7 @@ impl AscribeUserTypeCx<'me, 'gcx, 'tcx> {
         debug!("relate_type_and_user_type: ty of def-id is {:?}", ty);
         let ty = self.normalize(ty);
 
-        // We need to follow any provided projetions into the type.
-        //
-        // if we hit a ty var as we descend, then just skip the
-        // attempt to relate the mir local with any type.
-
-        struct HitTyVar;
-        let mut curr_projected_ty: Result<PlaceTy, HitTyVar>;
-        curr_projected_ty = Ok(PlaceTy::from_ty(ty));
-        for proj in projs {
-            let projected_ty = if let Ok(projected_ty) = curr_projected_ty {
-                projected_ty
-            } else {
-                break;
-            };
-            curr_projected_ty = projected_ty.projection_ty_core(
-                tcx, proj, |this, field, &()| {
-                    if this.to_ty(tcx).is_ty_var() {
-                        Err(HitTyVar)
-                    } else {
-                        let ty = this.field_ty(tcx, field);
-                        Ok(self.normalize(ty))
-                    }
-                });
-        }
-
-        if let Ok(projected_ty) = curr_projected_ty {
-            let ty = projected_ty.to_ty(tcx);
-            self.relate(mir_ty, variance, ty)?;
-        }
+        self.relate(mir_ty, Variance::Invariant, ty)?;
 
         // Prove the predicates coming along with `def_id`.
         //
diff --git a/src/librustc_tsan/Cargo.toml b/src/librustc_tsan/Cargo.toml
index f0618275f2f6a..d805833a7efc1 100644
--- a/src/librustc_tsan/Cargo.toml
+++ b/src/librustc_tsan/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 build = "build.rs"
 name = "rustc_tsan"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_tsan"
diff --git a/src/librustc_tsan/build.rs b/src/librustc_tsan/build.rs
index f63bb46b87468..ed9c37087c7e5 100644
--- a/src/librustc_tsan/build.rs
+++ b/src/librustc_tsan/build.rs
@@ -1,6 +1,3 @@
-extern crate build_helper;
-extern crate cmake;
-
 use std::env;
 use build_helper::sanitizer_lib_boilerplate;
 
@@ -8,6 +5,8 @@ use cmake::Config;
 
 fn main() {
     if let Some(llvm_config) = env::var_os("LLVM_CONFIG") {
+        build_helper::restore_library_path();
+
         let (native, target) = match sanitizer_lib_boilerplate("tsan") {
             Ok(native) => native,
             _ => return,
diff --git a/src/librustc_tsan/lib.rs b/src/librustc_tsan/lib.rs
index d6c8e54c18db7..3bdb86d313dcb 100644
--- a/src/librustc_tsan/lib.rs
+++ b/src/librustc_tsan/lib.rs
@@ -6,3 +6,5 @@
 #![unstable(feature = "sanitizer_runtime_lib",
             reason = "internal implementation detail of sanitizers",
             issue = "0")]
+
+#![deny(rust_2018_idioms)]
diff --git a/src/librustc_typeck/Cargo.toml b/src/librustc_typeck/Cargo.toml
index 68b28a60fdff7..dcfcd74257e6f 100644
--- a/src/librustc_typeck/Cargo.toml
+++ b/src/librustc_typeck/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_typeck"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "rustc_typeck"
@@ -14,7 +15,7 @@ arena = { path = "../libarena" }
 log = "0.4"
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 8e5eaa18b9de0..cde6eb22bb8ae 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -2,14 +2,15 @@
 //! The main routine here is `ast_ty_to_ty()`; each use is parameterized by an
 //! instance of `AstConv`.
 
-use errors::{Applicability, FatalError, DiagnosticId};
-use hir::{self, GenericArg, GenericArgs};
-use hir::def::Def;
-use hir::def_id::DefId;
-use hir::HirVec;
-use lint;
-use middle::resolve_lifetime as rl;
-use namespace::Namespace;
+use errors::{Applicability, DiagnosticId};
+use crate::hir::{self, GenericArg, GenericArgs};
+use crate::hir::def::Def;
+use crate::hir::def_id::DefId;
+use crate::hir::HirVec;
+use crate::lint;
+use crate::middle::resolve_lifetime as rl;
+use crate::namespace::Namespace;
+use rustc::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
 use rustc::traits;
 use rustc::ty::{self, Ty, TyCtxt, ToPredicate, TypeFoldable};
 use rustc::ty::{GenericParamDef, GenericParamDefKind};
@@ -17,15 +18,15 @@ use rustc::ty::subst::{Kind, Subst, Substs};
 use rustc::ty::wf::object_region_bounds;
 use rustc_data_structures::sync::Lrc;
 use rustc_target::spec::abi;
-use require_c_abi_if_variadic;
+use crate::require_c_abi_if_variadic;
 use smallvec::SmallVec;
 use syntax::ast;
 use syntax::feature_gate::{GateIssue, emit_feature_err};
 use syntax::ptr::P;
 use syntax::util::lev_distance::find_best_match_for_name;
 use syntax_pos::{DUMMY_SP, Span, MultiSpan};
-use util::common::ErrorReported;
-use util::nodemap::FxHashMap;
+use crate::util::common::ErrorReported;
+use crate::util::nodemap::FxHashMap;
 
 use std::collections::BTreeSet;
 use std::iter;
@@ -110,11 +111,10 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
     {
         let tcx = self.tcx();
         let lifetime_name = |def_id| {
-            tcx.hir().name(tcx.hir().as_local_node_id(def_id).unwrap()).as_interned_str()
+            tcx.hir().name_by_hir_id(tcx.hir().as_local_hir_id(def_id).unwrap()).as_interned_str()
         };
 
-        let hir_id = tcx.hir().node_to_hir_id(lifetime.id);
-        let r = match tcx.named_region(hir_id) {
+        let r = match tcx.named_region(lifetime.hir_id) {
             Some(rl::Region::Static) => {
                 tcx.types.re_static
             }
@@ -224,7 +224,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
         impl_trait
     }
 
-    /// Check that the correct number of generic arguments have been provided.
+    /// Checks that the correct number of generic arguments have been provided.
     /// Used specifically for function calls.
     pub fn check_generic_arg_count_for_call(
         tcx: TyCtxt,
@@ -256,7 +256,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
         ).0
     }
 
-    /// Check that the correct number of generic arguments have been provided.
+    /// Checks that the correct number of generic arguments have been provided.
     /// This is used both for datatypes and function calls.
     fn check_generic_arg_count(
         tcx: TyCtxt,
@@ -400,8 +400,8 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
 
     /// Creates the relevant generic argument substitutions
     /// corresponding to a set of generic parameters. This is a
-    /// rather complex little function. Let me try to explain the
-    /// role of each of its parameters:
+    /// rather complex function. Let us try to explain the role
+    /// of each of its parameters:
     ///
     /// To start, we are given the `def_id` of the thing we are
     /// creating the substitutions for, and a partial set of
@@ -417,9 +417,9 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
     /// we can append those and move on. Otherwise, it invokes the
     /// three callback functions:
     ///
-    /// - `args_for_def_id`: given the def-id `P`, supplies back the
+    /// - `args_for_def_id`: given the `DefId` `P`, supplies back the
     ///   generic arguments that were given to that parent from within
-    ///   the path; so e.g., if you have `<T as Foo>::Bar`, the def-id
+    ///   the path; so e.g., if you have `<T as Foo>::Bar`, the `DefId`
     ///   might refer to the trait `Foo`, and the arguments might be
     ///   `[T]`. The boolean value indicates whether to infer values
     ///   for arguments whose values were not explicitly provided.
@@ -500,19 +500,20 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                                 args.next();
                                 params.next();
                             }
-                            (GenericArg::Lifetime(_), GenericParamDefKind::Type { .. }) => {
-                                // We expected a type argument, but got a lifetime
-                                // argument. This is an error, but we need to handle it
-                                // gracefully so we can report sensible errors. In this
-                                // case, we're simply going to infer this argument.
-                                args.next();
-                            }
-                            (GenericArg::Type(_), GenericParamDefKind::Lifetime) => {
-                                // We expected a lifetime argument, but got a type
+                            (GenericArg::Type(_), GenericParamDefKind::Lifetime)
+                            | (GenericArg::Const(_), GenericParamDefKind::Lifetime) => {
+                                // We expected a lifetime argument, but got a type or const
                                 // argument. That means we're inferring the lifetimes.
                                 substs.push(inferred_kind(None, param, infer_types));
                                 params.next();
                             }
+                            (_, _) => {
+                                // We expected one kind of parameter, but the user provided
+                                // another. This is an error, but we need to handle it
+                                // gracefully so we can report sensible errors.
+                                // In this case, we're simply going to infer this argument.
+                                args.next();
+                            }
                         }
                     }
                     (Some(_), None) => {
@@ -524,12 +525,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                     (None, Some(&param)) => {
                         // If there are fewer arguments than parameters, it means
                         // we're inferring the remaining arguments.
-                        match param.kind {
-                            GenericParamDefKind::Lifetime | GenericParamDefKind::Type { .. } => {
-                                let kind = inferred_kind(Some(&substs), param, infer_types);
-                                substs.push(kind);
-                            }
-                        }
+                        substs.push(inferred_kind(Some(&substs), param, infer_types));
                         args.next();
                         params.next();
                     }
@@ -680,7 +676,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
     /// bound to a valid trait type. Returns the def_id for the defining trait.
     /// The type _cannot_ be a type other than a trait type.
     ///
-    /// If the `projections` argument is `None`, then assoc type bindings like `Foo<T=X>`
+    /// If the `projections` argument is `None`, then assoc type bindings like `Foo<T = X>`
     /// are disallowed. Otherwise, they are pushed onto the vector given.
     pub fn instantiate_mono_trait_ref(&self,
         trait_ref: &hir::TraitRef,
@@ -689,27 +685,13 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
     {
         self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1);
 
-        let trait_def_id = self.trait_def_id(trait_ref);
         self.ast_path_to_mono_trait_ref(trait_ref.path.span,
-                                        trait_def_id,
+                                        trait_ref.trait_def_id(),
                                         self_ty,
                                         trait_ref.path.segments.last().unwrap())
     }
 
-    /// Get the `DefId` of the given trait ref. It _must_ actually be a trait.
-    fn trait_def_id(&self, trait_ref: &hir::TraitRef) -> DefId {
-        let path = &trait_ref.path;
-        match path.def {
-            Def::Trait(trait_def_id) => trait_def_id,
-            Def::TraitAlias(alias_def_id) => alias_def_id,
-            Def::Err => {
-                FatalError.raise();
-            }
-            _ => unreachable!(),
-        }
-    }
-
-    /// The given trait ref must actually be a trait.
+    /// The given trait-ref must actually be a trait.
     pub(super) fn instantiate_poly_trait_ref_inner(&self,
         trait_ref: &hir::TraitRef,
         self_ty: Ty<'tcx>,
@@ -717,7 +699,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
         speculative: bool)
         -> (ty::PolyTraitRef<'tcx>, Option<Vec<Span>>)
     {
-        let trait_def_id = self.trait_def_id(trait_ref);
+        let trait_def_id = trait_ref.trait_def_id();
 
         debug!("instantiate_poly_trait_ref({:?}, def_id={:?})", trait_ref, trait_def_id);
 
@@ -892,8 +874,9 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                                           binding.item_name, binding.span)
         }?;
 
+        let hir_ref_id = self.tcx().hir().node_to_hir_id(ref_id);
         let (assoc_ident, def_scope) =
-            tcx.adjust_ident(binding.item_name, candidate.def_id(), ref_id);
+            tcx.adjust_ident(binding.item_name, candidate.def_id(), hir_ref_id);
         let assoc_ty = tcx.associated_items(candidate.def_id()).find(|i| {
             i.kind == ty::AssociatedKind::Type && i.ident.modern() == assoc_ident
         }).expect("missing associated type");
@@ -1109,7 +1092,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
             if !suggestions.is_empty() {
                 let msg = format!("if you meant to specify the associated {}, write",
                     if suggestions.len() == 1 { "type" } else { "types" });
-                err.multipart_suggestion_with_applicability(
+                err.multipart_suggestion(
                     &msg,
                     suggestions,
                     Applicability::MaybeIncorrect,
@@ -1158,8 +1141,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
             self.ast_region_to_region(lifetime, None)
         } else {
             self.compute_object_lifetime_bound(span, existential_predicates).unwrap_or_else(|| {
-                let hir_id = tcx.hir().node_to_hir_id(lifetime.id);
-                if tcx.named_region(hir_id).is_some() {
+                if tcx.named_region(lifetime.hir_id).is_some() {
                     self.ast_region_to_region(lifetime, None)
                 } else {
                     self.re_infer(span, None).unwrap_or_else(|| {
@@ -1185,7 +1167,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                                         trait_str: &str,
                                         name: &str) {
         struct_span_err!(self.tcx().sess, span, E0223, "ambiguous associated type")
-            .span_suggestion_with_applicability(
+            .span_suggestion(
                 span,
                 "use fully-qualified syntax",
                 format!("<{} as {}>::{}", type_str, trait_str, name),
@@ -1278,29 +1260,50 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
     }
 
     // Create a type from a path to an associated type.
-    // For a path `A::B::C::D`, `ty` and `ty_path_def` are the type and def for `A::B::C`
+    // For a path `A::B::C::D`, `qself_ty` and `qself_def` are the type and def for `A::B::C`
     // and item_segment is the path segment for `D`. We return a type and a def for
     // the whole path.
-    // Will fail except for `T::A` and `Self::A`; i.e., if `ty`/`ty_path_def` are not a type
+    // Will fail except for `T::A` and `Self::A`; i.e., if `qself_ty`/`qself_def` are not a type
     // parameter or `Self`.
-    pub fn associated_path_def_to_ty(&self,
-                                     ref_id: ast::NodeId,
-                                     span: Span,
-                                     ty: Ty<'tcx>,
-                                     ty_path_def: Def,
-                                     item_segment: &hir::PathSegment)
-                                     -> (Ty<'tcx>, Def)
-    {
+    pub fn associated_path_to_ty(
+        &self,
+        ref_id: ast::NodeId,
+        span: Span,
+        qself_ty: Ty<'tcx>,
+        qself_def: Def,
+        assoc_segment: &hir::PathSegment,
+        permit_variants: bool,
+    ) -> (Ty<'tcx>, Def) {
         let tcx = self.tcx();
-        let assoc_name = item_segment.ident;
+        let assoc_ident = assoc_segment.ident;
 
-        debug!("associated_path_def_to_ty: {:?}::{}", ty, assoc_name);
+        debug!("associated_path_to_ty: {:?}::{}", qself_ty, assoc_ident);
 
-        self.prohibit_generics(slice::from_ref(item_segment));
+        self.prohibit_generics(slice::from_ref(assoc_segment));
+
+        // Check if we have an enum variant.
+        let mut variant_resolution = None;
+        if let ty::Adt(adt_def, _) = qself_ty.sty {
+            if adt_def.is_enum() {
+                let variant_def = adt_def.variants.iter().find(|vd| {
+                    tcx.hygienic_eq(assoc_ident, vd.ident, adt_def.did)
+                });
+                if let Some(variant_def) = variant_def {
+                    let def = Def::Variant(variant_def.did);
+                    if permit_variants {
+                        check_type_alias_enum_variants_enabled(tcx, span);
+                        tcx.check_stability(variant_def.did, Some(ref_id), span);
+                        return (qself_ty, def);
+                    } else {
+                        variant_resolution = Some(def);
+                    }
+                }
+            }
+        }
 
         // Find the type of the associated item, and the trait where the associated
         // item is declared.
-        let bound = match (&ty.sty, ty_path_def) {
+        let bound = match (&qself_ty.sty, qself_def) {
             (_, Def::SelfTy(Some(_), Some(impl_def_id))) => {
                 // `Self` in an impl of a trait -- we have a concrete self type and a
                 // trait reference.
@@ -1313,77 +1316,62 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                 };
 
                 let candidates = traits::supertraits(tcx, ty::Binder::bind(trait_ref))
-                    .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_name));
+                    .filter(|r| self.trait_defines_associated_type_named(r.def_id(), assoc_ident));
 
-                match self.one_bound_for_assoc_type(candidates, "Self", assoc_name, span) {
+                match self.one_bound_for_assoc_type(candidates, "Self", assoc_ident, span) {
                     Ok(bound) => bound,
                     Err(ErrorReported) => return (tcx.types.err, Def::Err),
                 }
             }
             (&ty::Param(_), Def::SelfTy(Some(param_did), None)) |
             (&ty::Param(_), Def::TyParam(param_did)) => {
-                match self.find_bound_for_assoc_item(param_did, assoc_name, span) {
+                match self.find_bound_for_assoc_item(param_did, assoc_ident, span) {
                     Ok(bound) => bound,
                     Err(ErrorReported) => return (tcx.types.err, Def::Err),
                 }
             }
-            (&ty::Adt(adt_def, _substs), Def::Enum(_did)) => {
-                let ty_str = ty.to_string();
-                // Incorrect enum variant.
-                let mut err = tcx.sess.struct_span_err(
-                    span,
-                    &format!("no variant `{}` on enum `{}`", &assoc_name.as_str(), ty_str),
-                );
-                // Check if it was a typo.
-                let input = adt_def.variants.iter().map(|variant| &variant.ident.name);
-                if let Some(suggested_name) = find_best_match_for_name(
-                    input,
-                    &assoc_name.as_str(),
-                    None,
-                ) {
-                    err.span_suggestion_with_applicability(
+            _ => {
+                if variant_resolution.is_some() {
+                    // Variant in type position
+                    let msg = format!("expected type, found variant `{}`", assoc_ident);
+                    tcx.sess.span_err(span, &msg);
+                } else if qself_ty.is_enum() {
+                    // Report as incorrect enum variant rather than ambiguous type.
+                    let mut err = tcx.sess.struct_span_err(
                         span,
-                        "did you mean",
-                        format!("{}::{}", ty_str, suggested_name.to_string()),
-                        Applicability::MaybeIncorrect,
+                        &format!("no variant `{}` on enum `{}`", &assoc_ident.as_str(), qself_ty),
                     );
-                } else {
-                    err.span_label(span, "unknown variant");
-                }
-                err.emit();
-                return (tcx.types.err, Def::Err);
-            }
-            _ => {
-                // Check if we have an enum variant.
-                match ty.sty {
-                    ty::Adt(adt_def, _) if adt_def.is_enum() => {
-                        let variant_def = adt_def.variants.iter().find(|vd| {
-                            tcx.hygienic_eq(assoc_name, vd.ident, adt_def.did)
-                        });
-                        if let Some(variant_def) = variant_def {
-                            check_type_alias_enum_variants_enabled(tcx, span);
-
-                            let def = Def::Variant(variant_def.did);
-                            tcx.check_stability(def.def_id(), Some(ref_id), span);
-                            return (ty, def);
-                        }
-                    },
-                    _ => (),
-                }
-
-                // Don't print `TyErr` to the user.
-                if !ty.references_error() {
+                    // Check if it was a typo.
+                    let adt_def = qself_ty.ty_adt_def().expect("enum is not an ADT");
+                    if let Some(suggested_name) = find_best_match_for_name(
+                        adt_def.variants.iter().map(|variant| &variant.ident.name),
+                        &assoc_ident.as_str(),
+                        None,
+                    ) {
+                        err.span_suggestion(
+                            span,
+                            "did you mean",
+                            format!("{}::{}", qself_ty, suggested_name),
+                            Applicability::MaybeIncorrect,
+                        );
+                    } else {
+                        err.span_label(span, "unknown variant");
+                    }
+                    err.emit();
+                } else if !qself_ty.references_error() {
+                    // Don't print `TyErr` to the user.
                     self.report_ambiguous_associated_type(span,
-                                                          &ty.to_string(),
+                                                          &qself_ty.to_string(),
                                                           "Trait",
-                                                          &assoc_name.as_str());
+                                                          &assoc_ident.as_str());
                 }
                 return (tcx.types.err, Def::Err);
             }
         };
 
         let trait_did = bound.def_id();
-        let (assoc_ident, def_scope) = tcx.adjust_ident(assoc_name, trait_did, ref_id);
+        let hir_ref_id = self.tcx().hir().node_to_hir_id(ref_id);
+        let (assoc_ident, def_scope) = tcx.adjust_ident(assoc_ident, trait_did, hir_ref_id);
         let item = tcx.associated_items(trait_did).find(|i| {
             Namespace::from(i.kind) == Namespace::Type &&
                 i.ident.modern() == assoc_ident
@@ -1394,11 +1382,35 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
 
         let def = Def::AssociatedTy(item.def_id);
         if !item.vis.is_accessible_from(def_scope, tcx) {
-            let msg = format!("{} `{}` is private", def.kind_name(), assoc_name);
+            let msg = format!("{} `{}` is private", def.kind_name(), assoc_ident);
             tcx.sess.span_err(span, &msg);
         }
         tcx.check_stability(item.def_id, Some(ref_id), span);
 
+        if let Some(variant_def) = variant_resolution {
+            let mut err = tcx.struct_span_lint_node(
+                AMBIGUOUS_ASSOCIATED_ITEMS,
+                ref_id,
+                span,
+                "ambiguous associated item",
+            );
+
+            let mut could_refer_to = |def: Def, also| {
+                let note_msg = format!("`{}` could{} refer to {} defined here",
+                                       assoc_ident, also, def.kind_name());
+                err.span_note(tcx.def_span(def.def_id()), &note_msg);
+            };
+            could_refer_to(variant_def, "");
+            could_refer_to(def, " also");
+
+            err.span_suggestion(
+                span,
+                "use fully-qualified syntax",
+                format!("<{} as {}>::{}", qself_ty, "Trait", assoc_ident),
+                Applicability::HasPlaceholders,
+            ).emit();
+        }
+
         (ty, def)
     }
 
@@ -1443,9 +1455,10 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
         let mut has_err = false;
         for segment in segments {
             segment.with_generic_args(|generic_args| {
-                let (mut err_for_lt, mut err_for_ty) = (false, false);
+                let (mut err_for_lt, mut err_for_ty, mut err_for_ct) = (false, false, false);
                 for arg in &generic_args.args {
                     let (mut span_err, span, kind) = match arg {
+                        // FIXME(varkor): unify E0109, E0110 and E0111.
                         hir::GenericArg::Lifetime(lt) => {
                             if err_for_lt { continue }
                             err_for_lt = true;
@@ -1464,10 +1477,18 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                              ty.span,
                              "type")
                         }
+                        hir::GenericArg::Const(ct) => {
+                            if err_for_ct { continue }
+                            err_for_ct = true;
+                            (struct_span_err!(self.tcx().sess, ct.span, E0111,
+                                              "const parameters are not allowed on this type"),
+                             ct.span,
+                             "const")
+                        }
                     };
                     span_err.span_label(span, format!("{} argument not allowed", kind))
                             .emit();
-                    if err_for_lt && err_for_ty {
+                    if err_for_lt && err_for_ty && err_for_ct {
                         break;
                     }
                 }
@@ -1668,12 +1689,13 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                 assert_eq!(opt_self_ty, None);
                 self.prohibit_generics(&path.segments);
 
-                let node_id = tcx.hir().as_local_node_id(did).unwrap();
-                let item_id = tcx.hir().get_parent_node(node_id);
-                let item_def_id = tcx.hir().local_def_id(item_id);
+                let hir_id = tcx.hir().as_local_hir_id(did).unwrap();
+                let item_id = tcx.hir().get_parent_node_by_hir_id(hir_id);
+                let item_def_id = tcx.hir().local_def_id_from_hir_id(item_id);
                 let generics = tcx.generics_of(item_def_id);
-                let index = generics.param_def_id_to_index[&tcx.hir().local_def_id(node_id)];
-                tcx.mk_ty_param(index, tcx.hir().name(node_id).as_interned_str())
+                let index = generics.param_def_id_to_index[
+                    &tcx.hir().local_def_id_from_hir_id(hir_id)];
+                tcx.mk_ty_param(index, tcx.hir().name_by_hir_id(hir_id).as_interned_str())
             }
             Def::SelfTy(_, Some(def_id)) => {
                 // `Self` in impl (we know the concrete type).
@@ -1773,13 +1795,13 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
                 } else {
                     Def::Err
                 };
-                self.associated_path_def_to_ty(ast_ty.id, ast_ty.span, ty, def, segment).0
+                self.associated_path_to_ty(ast_ty.id, ast_ty.span, ty, def, segment, false).0
             }
             hir::TyKind::Array(ref ty, ref length) => {
                 let length_def_id = tcx.hir().local_def_id(length.id);
                 let substs = Substs::identity_for_item(tcx, length_def_id);
                 let length = ty::LazyConst::Unevaluated(length_def_id, substs);
-                let length = tcx.intern_lazy_const(length);
+                let length = tcx.mk_lazy_const(length);
                 let array_ty = tcx.mk_ty(ty::Array(self.ast_ty_to_ty(&ty), length));
                 self.normalize_ty(ast_ty.span, array_ty)
             }
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index 1767af4870d3b..0e6ab5b1eb3b2 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -1,5 +1,7 @@
-use check::{FnCtxt, Expectation, Diverges, Needs};
-use check::coercion::CoerceMany;
+use crate::check::{FnCtxt, Expectation, Diverges, Needs};
+use crate::check::coercion::CoerceMany;
+use crate::util::nodemap::FxHashMap;
+use errors::Applicability;
 use rustc::hir::{self, PatKind};
 use rustc::hir::def::{Def, CtorKind};
 use rustc::hir::pat_util::EnumerateAndAdjustIterator;
@@ -12,7 +14,6 @@ use syntax::source_map::Spanned;
 use syntax::ptr::P;
 use syntax::util::lev_distance::find_best_match_for_name;
 use syntax_pos::Span;
-use util::nodemap::FxHashMap;
 
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::cmp;
@@ -226,7 +227,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 self.demand_eqtype_pat(pat.span, expected, rhs_ty, match_discrim_span);
                 common_type
             }
-            PatKind::Binding(ba, var_id, _, ref sub) => {
+            PatKind::Binding(ba, var_id, _, _, ref sub) => {
                 let bm = if ba == hir::BindingAnnotation::Unannotated {
                     def_bm
                 } else {
@@ -688,6 +689,8 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
             CoerceMany::with_coercion_sites(coerce_first, arms)
         };
 
+        let mut other_arms = vec![];  // used only for diagnostics
+        let mut prior_arm_ty = None;
         for (i, (arm, pats_diverge)) in arms.iter().zip(all_arm_pats_diverge).enumerate() {
             if let Some(ref g) = arm.guard {
                 self.diverges.set(pats_diverge);
@@ -708,17 +711,36 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                 _ => false
             };
 
+            let arm_span = if let hir::ExprKind::Block(ref blk, _) = arm.body.node {
+                // Point at the block expr instead of the entire block
+                blk.expr.as_ref().map(|e| e.span).unwrap_or(arm.body.span)
+            } else {
+                arm.body.span
+            };
             if is_if_let_fallback {
                 let cause = self.cause(expr.span, ObligationCauseCode::IfExpressionWithNoElse);
                 assert!(arm_ty.is_unit());
                 coercion.coerce_forced_unit(self, &cause, &mut |_| (), true);
             } else {
-                let cause = self.cause(expr.span, ObligationCauseCode::MatchExpressionArm {
-                    arm_span: arm.body.span,
-                    source: match_src
-                });
+                let cause = if i == 0 {
+                    // The reason for the first arm to fail is not that the match arms diverge,
+                    // but rather that there's a prior obligation that doesn't hold.
+                    self.cause(arm_span, ObligationCauseCode::BlockTailExpression(arm.body.id))
+                } else {
+                    self.cause(expr.span, ObligationCauseCode::MatchExpressionArm {
+                        arm_span,
+                        source: match_src,
+                        prior_arms: other_arms.clone(),
+                        last_ty: prior_arm_ty.unwrap(),
+                    })
+                };
                 coercion.coerce(self, &cause, &arm.body, arm_ty);
             }
+            other_arms.push(arm_span);
+            if other_arms.len() > 5 {
+                other_arms.remove(0);
+            }
+            prior_arm_ty = Some(arm_ty);
         }
 
         // We won't diverge unless the discriminant or all arms diverge.
@@ -783,7 +805,8 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                 report_unexpected_variant_def(tcx, &def, pat.span, qpath);
                 return tcx.types.err;
             }
-            Def::VariantCtor(_, CtorKind::Fictive) => {
+            Def::VariantCtor(_, CtorKind::Fictive) |
+            Def::VariantCtor(_, CtorKind::Fn) => {
                 report_unexpected_variant_def(tcx, &def, pat.span, qpath);
                 return tcx.types.err;
             }
@@ -989,7 +1012,13 @@ https://doc.rust-lang.org/reference/types.html#trait-objects");
                     let suggested_name =
                         find_best_match_for_name(input, &ident.as_str(), None);
                     if let Some(suggested_name) = suggested_name {
-                        err.span_suggestion(*span, "did you mean", suggested_name.to_string());
+                        err.span_suggestion(
+                            *span,
+                            "did you mean",
+                            suggested_name.to_string(),
+                            Applicability::MaybeIncorrect,
+                        );
+
                         // we don't want to throw `E0027` in case we have thrown `E0026` for them
                         unmentioned_fields.retain(|&x| x.as_str() != suggested_name.as_str());
                     }
diff --git a/src/librustc_typeck/check/autoderef.rs b/src/librustc_typeck/check/autoderef.rs
index 35ac4f3957eb4..f863cfe1887db 100644
--- a/src/librustc_typeck/check/autoderef.rs
+++ b/src/librustc_typeck/check/autoderef.rs
@@ -1,6 +1,7 @@
 use super::{FnCtxt, PlaceOp, Needs};
 use super::method::MethodCallee;
 
+use rustc::hir;
 use rustc::infer::{InferCtxt, InferOk};
 use rustc::session::DiagnosticMessageId;
 use rustc::traits::{self, TraitEngine};
@@ -9,7 +10,7 @@ use rustc::ty::{ToPredicate, TypeFoldable};
 use rustc::ty::adjustment::{Adjustment, Adjust, OverloadedDeref};
 
 use syntax_pos::Span;
-use syntax::ast::{self, Ident};
+use syntax::ast::Ident;
 
 use std::iter;
 
@@ -21,7 +22,7 @@ enum AutoderefKind {
 
 pub struct Autoderef<'a, 'gcx: 'tcx, 'tcx: 'a> {
     infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
     param_env: ty::ParamEnv<'tcx>,
     steps: Vec<(Ty<'tcx>, AutoderefKind)>,
     cur_ty: Ty<'tcx>,
@@ -87,7 +88,7 @@ impl<'a, 'gcx, 'tcx> Iterator for Autoderef<'a, 'gcx, 'tcx> {
 impl<'a, 'gcx, 'tcx> Autoderef<'a, 'gcx, 'tcx> {
     pub fn new(infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
                param_env: ty::ParamEnv<'tcx>,
-               body_id: ast::NodeId,
+               body_id: hir::HirId,
                span: Span,
                base_ty: Ty<'tcx>)
                -> Autoderef<'a, 'gcx, 'tcx>
diff --git a/src/librustc_typeck/check/callee.rs b/src/librustc_typeck/check/callee.rs
index c59c143f74b62..1bbb93b4e461d 100644
--- a/src/librustc_typeck/check/callee.rs
+++ b/src/librustc_typeck/check/callee.rs
@@ -15,9 +15,9 @@ use syntax_pos::Span;
 
 use rustc::hir;
 
-/// Check that it is legal to call methods of the trait corresponding
+/// Checks that it is legal to call methods of the trait corresponding
 /// to `trait_id` (this only cares about the trait, not the specific
-/// method that is called)
+/// method that is called).
 pub fn check_legal_trait_for_method_call(tcx: TyCtxt, span: Span, trait_id: DefId) {
     if tcx.lang_items().drop_trait() == Some(trait_id) {
         struct_span_err!(tcx.sess, span, E0040, "explicit use of destructor method")
@@ -29,7 +29,7 @@ pub fn check_legal_trait_for_method_call(tcx: TyCtxt, span: Span, trait_id: DefI
 enum CallStep<'tcx> {
     Builtin(Ty<'tcx>),
     DeferredClosure(ty::FnSig<'tcx>),
-    /// e.g., enum variant constructors
+    /// E.g., enum variant constructors.
     Overloaded(MethodCallee<'tcx>),
 }
 
@@ -269,7 +269,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     );
 
                     if let Some(ref path) = unit_variant {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             call_expr.span,
                             &format!(
                                 "`{}` is a unit variant, you need to write it \
@@ -294,7 +294,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 self.tcx.sess.source_map().is_multiline(call_expr.span);
                             if call_is_multiline {
                                 let span = self.tcx.sess.source_map().next_point(callee.span);
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     span,
                                     "try adding a semicolon",
                                     ";".to_owned(),
diff --git a/src/librustc_typeck/check/cast.rs b/src/librustc_typeck/check/cast.rs
index 3f185ba194903..317d6bbd78592 100644
--- a/src/librustc_typeck/check/cast.rs
+++ b/src/librustc_typeck/check/cast.rs
@@ -31,8 +31,8 @@
 use super::FnCtxt;
 
 use errors::{DiagnosticBuilder,Applicability};
-use hir::def_id::DefId;
-use lint;
+use crate::hir::def_id::DefId;
+use crate::lint;
 use rustc::hir;
 use rustc::session::Session;
 use rustc::traits;
@@ -43,7 +43,7 @@ use rustc::ty::subst::Substs;
 use rustc::middle::lang_items;
 use syntax::ast;
 use syntax_pos::Span;
-use util::common::ErrorReported;
+use crate::util::common::ErrorReported;
 
 /// Reifies a cast check to be checked once we have full type information for
 /// a function context.
@@ -140,7 +140,7 @@ enum CastError {
     CastToBool,
     CastToChar,
     DifferingKinds,
-    /// Cast of thin to fat raw ptr (eg. `*const () as *const [u8]`)
+    /// Cast of thin to fat raw ptr (e.g., `*const () as *const [u8]`).
     SizedUnsizedCast,
     IllegalCast,
     NeedDeref,
@@ -213,7 +213,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
                                        fcx.ty_to_string(self.expr_ty),
                                        cast_ty));
                 if let Ok(snippet) = fcx.sess().source_map().span_to_snippet(self.expr.span) {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         self.expr.span,
                         "dereference the expression",
                         format!("*{}", snippet),
@@ -263,7 +263,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
                 if self.expr_ty.is_numeric() {
                     match fcx.tcx.sess.source_map().span_to_snippet(self.expr.span) {
                         Ok(snippet) => {
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 self.span,
                                 "compare with zero instead",
                                 format!("{} != 0", snippet),
@@ -294,7 +294,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
                                   .emit();
             }
             CastError::SizedUnsizedCast => {
-                use structured_errors::{SizedUnsizedCastError, StructuredDiagnostic};
+                use crate::structured_errors::{SizedUnsizedCastError, StructuredDiagnostic};
                 SizedUnsizedCastError::new(&fcx.tcx.sess,
                                            self.span,
                                            self.expr_ty,
@@ -314,7 +314,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
                 err.note("The type information given here is insufficient to check whether \
                           the pointer cast is valid");
                 if unknown_cast_to {
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         self.cast_span,
                         "consider giving more type information",
                         String::new(),
@@ -345,7 +345,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
                 if self.cast_ty.is_trait() {
                     match fcx.tcx.sess.source_map().span_to_snippet(self.cast_span) {
                         Ok(s) => {
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 self.cast_span,
                                 "try casting to a reference instead",
                                 format!("&{}{}", mtstr, s),
@@ -367,7 +367,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
             ty::Adt(def, ..) if def.is_box() => {
                 match fcx.tcx.sess.source_map().span_to_snippet(self.cast_span) {
                     Ok(s) => {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             self.cast_span,
                             "try casting to a `Box` instead",
                             format!("Box<{}>", s),
@@ -441,7 +441,7 @@ impl<'a, 'gcx, 'tcx> CastCheck<'tcx> {
         }
     }
 
-    /// Check a cast, and report an error if one exists. In some cases, this
+    /// Checks a cast, and report an error if one exists. In some cases, this
     /// can return Ok and create type errors in the fcx rather than returning
     /// directly. coercion-cast is handled in check instead of here.
     fn do_check(&self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Result<CastKind, CastError> {
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index df83c92fde5b4..722af8f0e778d 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -2,8 +2,8 @@
 
 use super::{check_fn, Expectation, FnCtxt, GeneratorTypes};
 
-use astconv::AstConv;
-use middle::region;
+use crate::astconv::AstConv;
+use crate::middle::region;
 use rustc::hir::def_id::DefId;
 use rustc::infer::{InferOk, InferResult};
 use rustc::infer::LateBoundRegionConversionTime;
@@ -365,7 +365,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     ///
     /// # Arguments
     ///
-    /// - `expr_def_id`: the def-id of the closure expression
+    /// - `expr_def_id`: the `DefId` of the closure expression
     /// - `decl`: the HIR declaration of the closure
     /// - `body`: the body of the closure
     /// - `expected_sig`: the expected signature (if any). Note that
@@ -458,7 +458,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         self.closure_sigs(expr_def_id, body, error_sig)
     }
 
-    /// Enforce the user's types against the expectation.  See
+    /// Enforce the user's types against the expectation. See
     /// `sig_of_closure_with_expectation` for details on the overall
     /// strategy.
     fn check_supplied_sig_against_expectation(
@@ -641,7 +641,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             .liberate_late_bound_regions(expr_def_id, &bound_sig);
         let liberated_sig = self.inh.normalize_associated_types_in(
             body.value.span,
-            body.value.id,
+            body.value.hir_id,
             self.param_env,
             &liberated_sig,
         );
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index a82a0d3ce5232..90071e3f3634a 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -1,7 +1,7 @@
 //! # Type Coercion
 //!
 //! Under certain circumstances we will coerce from one type to another,
-//! for example by auto-borrowing.  This occurs in situations where the
+//! for example by auto-borrowing. This occurs in situations where the
 //! compiler has a firm 'expected type' that was supplied from the user,
 //! and where the actual type is similar to that expected type in purpose
 //! but not in representation (so actual subtyping is inappropriate).
@@ -9,24 +9,24 @@
 //! ## Reborrowing
 //!
 //! Note that if we are expecting a reference, we will *reborrow*
-//! even if the argument provided was already a reference.  This is
+//! even if the argument provided was already a reference. This is
 //! useful for freezing mut/const things (that is, when the expected is &T
 //! but you have &const T or &mut T) and also for avoiding the linearity
-//! of mut things (when the expected is &mut T and you have &mut T).  See
+//! of mut things (when the expected is &mut T and you have &mut T). See
 //! the various `src/test/run-pass/coerce-reborrow-*.rs` tests for
 //! examples of where this is useful.
 //!
 //! ## Subtle note
 //!
 //! When deciding what type coercions to consider, we do not attempt to
-//! resolve any type variables we may encounter.  This is because `b`
+//! resolve any type variables we may encounter. This is because `b`
 //! represents the expected type "as the user wrote it", meaning that if
 //! the user defined a generic function like
 //!
 //!    fn foo<A>(a: A, b: A) { ... }
 //!
 //! and then we wrote `foo(&1, @2)`, we will not auto-borrow
-//! either argument.  In older code we went to some lengths to
+//! either argument. In older code we went to some lengths to
 //! resolve the `b` variable, which could mean that we'd
 //! auto-borrow later arguments but not earlier ones, which
 //! seems very confusing.
@@ -39,18 +39,18 @@
 //!    foo::<&int>(@1, @2)
 //!
 //! then we *will* auto-borrow, because we can't distinguish this from a
-//! function that declared `&int`.  This is inconsistent but it's easiest
+//! function that declared `&int`. This is inconsistent but it's easiest
 //! at the moment. The right thing to do, I think, is to consider the
 //! *unsubstituted* type when deciding whether to auto-borrow, but the
 //! *substituted* type when considering the bounds and so forth. But most
 //! of our methods don't give access to the unsubstituted type, and
-//! rightly so because they'd be error-prone.  So maybe the thing to do is
+//! rightly so because they'd be error-prone. So maybe the thing to do is
 //! to actually determine the kind of coercions that should occur
-//! separately and pass them in.  Or maybe it's ok as is.  Anyway, it's
-//! sort of a minor point so I've opted to leave it for later---after all
+//! separately and pass them in. Or maybe it's ok as is. Anyway, it's
+//! sort of a minor point so I've opted to leave it for later -- after all,
 //! we may want to adjust precisely when coercions occur.
 
-use check::{FnCtxt, Needs};
+use crate::check::{FnCtxt, Needs};
 use errors::DiagnosticBuilder;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
@@ -1031,8 +1031,8 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
         }
     }
 
-    /// Return the "expected type" with which this coercion was
-    /// constructed.  This represents the "downward propagated" type
+    /// Returns the "expected type" with which this coercion was
+    /// constructed. This represents the "downward propagated" type
     /// that was given to us at the start of typing whatever construct
     /// we are typing (e.g., the match expression).
     ///
@@ -1199,7 +1199,6 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
                     (self.final_ty.unwrap_or(self.expected_ty), expression_ty)
                 };
 
-                let reason_label = "expected because of this statement";
                 let mut db;
                 match cause.code {
                     ObligationCauseCode::ReturnNoExpression => {
@@ -1209,34 +1208,23 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
                         db.span_label(cause.span, "return type is not `()`");
                     }
                     ObligationCauseCode::BlockTailExpression(blk_id) => {
-                        db = fcx.report_mismatched_types(cause, expected, found, err);
-
-                        let expr = expression.unwrap_or_else(|| {
-                            span_bug!(cause.span,
-                                      "supposed to be part of a block tail expression, but the \
-                                       expression is empty");
-                        });
-                        fcx.suggest_mismatched_types_on_tail(
-                            &mut db,
-                            expr,
+                        let parent_id = fcx.tcx.hir().get_parent_node(blk_id);
+                        db = self.report_return_mismatched_types(
+                            cause,
                             expected,
                             found,
-                            cause.span,
-                            blk_id,
+                            err,
+                            fcx,
+                            parent_id,
+                            expression.map(|expr| (expr, blk_id)),
                         );
-                        if let Some(sp) = fcx.ret_coercion_span.borrow().as_ref() {
-                            if !sp.overlaps(cause.span) {
-                                db.span_label(*sp, reason_label);
-                            }
-                        }
+                    }
+                    ObligationCauseCode::ReturnType(id) => {
+                        db = self.report_return_mismatched_types(
+                            cause, expected, found, err, fcx, id, None);
                     }
                     _ => {
                         db = fcx.report_mismatched_types(cause, expected, found, err);
-                        if let Some(sp) = fcx.ret_coercion_span.borrow().as_ref() {
-                            if !sp.overlaps(cause.span) {
-                                db.span_label(*sp, reason_label);
-                            }
-                        }
                     }
                 }
 
@@ -1251,6 +1239,59 @@ impl<'gcx, 'tcx, 'exprs, E> CoerceMany<'gcx, 'tcx, 'exprs, E>
         }
     }
 
+    fn report_return_mismatched_types<'a>(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        expected: Ty<'tcx>,
+        found: Ty<'tcx>,
+        err: TypeError<'tcx>,
+        fcx: &FnCtxt<'a, 'gcx, 'tcx>,
+        id: syntax::ast::NodeId,
+        expression: Option<(&'gcx hir::Expr, syntax::ast::NodeId)>,
+    ) -> DiagnosticBuilder<'a> {
+        let mut db = fcx.report_mismatched_types(cause, expected, found, err);
+
+        let mut pointing_at_return_type = false;
+        let mut return_sp = None;
+
+        // Verify that this is a tail expression of a function, otherwise the
+        // label pointing out the cause for the type coercion will be wrong
+        // as prior return coercions would not be relevant (#57664).
+        let parent_id = fcx.tcx.hir().get_parent_node(id);
+        let fn_decl = if let Some((expr, blk_id)) = expression {
+            pointing_at_return_type = fcx.suggest_mismatched_types_on_tail(
+                &mut db,
+                expr,
+                expected,
+                found,
+                cause.span,
+                blk_id,
+            );
+            let parent = fcx.tcx.hir().get(parent_id);
+            fcx.get_node_fn_decl(parent).map(|(fn_decl, _, is_main)| (fn_decl, is_main))
+        } else {
+            fcx.get_fn_decl(parent_id)
+        };
+
+        if let (Some((fn_decl, can_suggest)), _) = (fn_decl, pointing_at_return_type) {
+            if expression.is_none() {
+                pointing_at_return_type |= fcx.suggest_missing_return_type(
+                    &mut db, &fn_decl, expected, found, can_suggest);
+            }
+            if !pointing_at_return_type {
+                return_sp = Some(fn_decl.output.span()); // `impl Trait` return type
+            }
+        }
+        if let (Some(sp), Some(return_sp)) = (fcx.ret_coercion_span.borrow().as_ref(), return_sp) {
+            db.span_label(return_sp, "expected because this return type...");
+            db.span_label( *sp, format!(
+                "...is found to be `{}` here",
+                fcx.resolve_type_vars_with_obligations(expected),
+            ));
+        }
+        db
+    }
+
     pub fn complete<'a>(self, fcx: &FnCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
         if let Some(final_ty) = self.final_ty {
             final_ty
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 8c193cc8ff1a3..5f1c2efb6a457 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -17,10 +17,10 @@ use super::{Inherited, FnCtxt, potentially_plural_count};
 ///
 /// # Parameters
 ///
-/// - impl_m: type of the method we are checking
-/// - impl_m_span: span to use for reporting errors
-/// - trait_m: the method in the trait
-/// - impl_trait_ref: the TraitRef corresponding to the trait implementation
+/// - `impl_m`: type of the method we are checking
+/// - `impl_m_span`: span to use for reporting errors
+/// - `trait_m`: the method in the trait
+/// - `impl_trait_ref`: the TraitRef corresponding to the trait implementation
 
 pub fn compare_impl_method<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                      impl_m: &ty::AssociatedItem,
@@ -84,10 +84,11 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     // `ObligationCause` (and the `FnCtxt`). This is what
     // `regionck_item` expects.
     let impl_m_node_id = tcx.hir().as_local_node_id(impl_m.def_id).unwrap();
+    let impl_m_hir_id = tcx.hir().node_to_hir_id(impl_m_node_id);
 
     let cause = ObligationCause {
         span: impl_m_span,
-        body_id: impl_m_node_id,
+        body_id: impl_m_hir_id,
         code: ObligationCauseCode::CompareImplMethodObligation {
             item_name: impl_m.ident.name,
             impl_item_def_id: impl_m.def_id,
@@ -205,7 +206,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     // Construct trait parameter environment and then shift it into the placeholder viewpoint.
     // The key step here is to update the caller_bounds's predicates to be
     // the new hybrid bounds we computed.
-    let normalize_cause = traits::ObligationCause::misc(impl_m_span, impl_m_node_id);
+    let normalize_cause = traits::ObligationCause::misc(impl_m_span, impl_m_hir_id);
     let param_env = ty::ParamEnv::new(
         tcx.intern_predicates(&hybrid_preds.predicates),
         Reveal::UserFacing,
@@ -262,7 +263,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         );
         let impl_sig =
             inh.normalize_associated_types_in(impl_m_span,
-                                              impl_m_node_id,
+                                              impl_m_hir_id,
                                               param_env,
                                               &impl_sig);
         let impl_fty = tcx.mk_fn_ptr(ty::Binder::bind(impl_sig));
@@ -275,7 +276,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             trait_sig.subst(tcx, trait_to_skol_substs);
         let trait_sig =
             inh.normalize_associated_types_in(impl_m_span,
-                                              impl_m_node_id,
+                                              impl_m_hir_id,
                                               param_env,
                                               &trait_sig);
         let trait_fty = tcx.mk_fn_ptr(ty::Binder::bind(trait_sig));
@@ -316,7 +317,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 if let Some(trait_err_span) = trait_err_span {
                     if let Ok(trait_err_str) = tcx.sess.source_map()
                                                        .span_to_snippet(trait_err_span) {
-                        diag.span_suggestion_with_applicability(
+                        diag.span_suggestion(
                             impl_err_span,
                             "consider change the type to match the mutability in trait",
                             trait_err_str,
@@ -347,8 +348,8 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
         // Finally, resolve all regions. This catches wily misuses of
         // lifetime parameters.
-        let fcx = FnCtxt::new(&inh, param_env, impl_m_node_id);
-        fcx.regionck_item(impl_m_node_id, impl_m_span, &[]);
+        let fcx = FnCtxt::new(&inh, param_env, impl_m_hir_id);
+        fcx.regionck_item(impl_m_hir_id, impl_m_span, &[]);
 
         Ok(())
     })
@@ -736,8 +737,8 @@ fn compare_synthetic_generics<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         in impl_m_type_params.zip(trait_m_type_params)
     {
         if impl_synthetic != trait_synthetic {
-            let impl_node_id = tcx.hir().as_local_node_id(impl_def_id).unwrap();
-            let impl_span = tcx.hir().span(impl_node_id);
+            let impl_hir_id = tcx.hir().as_local_hir_id(impl_def_id).unwrap();
+            let impl_span = tcx.hir().span_by_hir_id(impl_hir_id);
             let trait_span = tcx.def_span(trait_def_id);
             let mut err = struct_span_err!(tcx.sess,
                                            impl_span,
@@ -784,7 +785,7 @@ fn compare_synthetic_generics<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                             .span_to_snippet(trait_m.generics.span)
                             .ok()?;
 
-                        err.multipart_suggestion_with_applicability(
+                        err.multipart_suggestion(
                             "try changing the `impl Trait` argument to a generic parameter",
                             vec![
                                 // replace `impl Trait` with `T`
@@ -839,8 +840,9 @@ fn compare_synthetic_generics<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                         let bounds = impl_m.generics.params.iter().find_map(|param| {
                             match param.kind {
                                 GenericParamKind::Lifetime { .. } => None,
-                                GenericParamKind::Type { .. } => {
-                                    if param.id == impl_node_id {
+                                GenericParamKind::Type { .. } |
+                                GenericParamKind::Const { .. } => {
+                                    if param.hir_id == impl_hir_id {
                                         Some(&param.bounds)
                                     } else {
                                         None
@@ -855,7 +857,7 @@ fn compare_synthetic_generics<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                             .span_to_snippet(bounds)
                             .ok()?;
 
-                        err.multipart_suggestion_with_applicability(
+                        err.multipart_suggestion(
                             "try removing the generic parameter and using `impl Trait` instead",
                             vec![
                                 // delete generic parameters
@@ -903,22 +905,23 @@ pub fn compare_const_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         // Create a parameter environment that represents the implementation's
         // method.
         let impl_c_node_id = tcx.hir().as_local_node_id(impl_c.def_id).unwrap();
+        let impl_c_hir_id = tcx.hir().node_to_hir_id(impl_c_node_id);
 
         // Compute placeholder form of impl and trait const tys.
         let impl_ty = tcx.type_of(impl_c.def_id);
         let trait_ty = tcx.type_of(trait_c.def_id).subst(tcx, trait_to_impl_substs);
-        let mut cause = ObligationCause::misc(impl_c_span, impl_c_node_id);
+        let mut cause = ObligationCause::misc(impl_c_span, impl_c_hir_id);
 
         // There is no "body" here, so just pass dummy id.
         let impl_ty = inh.normalize_associated_types_in(impl_c_span,
-                                                        impl_c_node_id,
+                                                        impl_c_hir_id,
                                                         param_env,
                                                         &impl_ty);
 
         debug!("compare_const_impl: impl_ty={:?}", impl_ty);
 
         let trait_ty = inh.normalize_associated_types_in(impl_c_span,
-                                                         impl_c_node_id,
+                                                         impl_c_hir_id,
                                                          param_env,
                                                          &trait_ty);
 
@@ -973,7 +976,7 @@ pub fn compare_const_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
             return;
         }
 
-        let fcx = FnCtxt::new(&inh, param_env, impl_c_node_id);
-        fcx.regionck_item(impl_c_node_id, impl_c_span, &[]);
+        let fcx = FnCtxt::new(&inh, param_env, impl_c_hir_id);
+        fcx.regionck_item(impl_c_hir_id, impl_c_span, &[]);
     });
 }
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index c0cedd77440d9..8b80fba4d19d0 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -1,4 +1,4 @@
-use check::FnCtxt;
+use crate::check::FnCtxt;
 use rustc::infer::InferOk;
 use rustc::traits::{ObligationCause, ObligationCauseCode};
 
@@ -143,7 +143,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     let expr_text = print::to_string(print::NO_ANN, |s| s.print_expr(expr));
                     let suggestions = compatible_variants
                         .map(|v| format!("{}({})", v, expr_text));
-                    err.span_suggestions_with_applicability(
+                    err.span_suggestions(
                         expr.span,
                         "try using a variant of the expected type",
                         suggestions,
@@ -210,7 +210,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     /// ```
     /// opt.map(|arg| { takes_ref(arg) });
     /// ```
-    fn can_use_as_ref(&self, expr: &hir::Expr) -> Option<(Span, &'static str, String)> {
+    fn can_use_as_ref(
+        &self,
+        expr: &hir::Expr,
+    ) -> Option<(Span, &'static str, String)> {
         if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = expr.node {
             if let hir::def::Def::Local(id) = path.def {
                 let parent = self.tcx.hir().get_parent_node(id);
@@ -224,7 +227,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         node: hir::ExprKind::MethodCall(path, span, expr),
                         ..
                     })), 1) = (self.tcx.hir().find(parent), decl.inputs.len()) {
-                        let self_ty = self.tables.borrow().node_id_to_type(expr[0].hir_id);
+                        let self_ty = self.tables.borrow().node_type(expr[0].hir_id);
                         let self_ty = format!("{:?}", self_ty);
                         let name = path.ident.as_str();
                         let is_as_ref_able = (
@@ -233,10 +236,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             self_ty.starts_with("std::option::Option") ||
                             self_ty.starts_with("std::result::Result")
                         ) && (name == "map" || name == "and_then");
-                        if is_as_ref_able {
-                            return Some((span.shrink_to_lo(),
-                                         "consider using `as_ref` instead",
-                                         "as_ref().".into()));
+                        match (is_as_ref_able, self.sess().source_map().span_to_snippet(*span)) {
+                            (true, Ok(src)) => {
+                                return Some((*span, "consider using `as_ref` instead",
+                                             format!("as_ref().{}", src)));
+                            },
+                            _ => ()
                         }
                     }
                 }
@@ -430,7 +435,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         match expr.node {
             // All built-in range literals but `..=` and `..` desugar to Structs
-            ExprKind::Struct(QPath::Resolved(None, ref path), _, _) |
+            ExprKind::Struct(ref qpath, _, _) => {
+                if let QPath::Resolved(None, ref path) = **qpath {
+                    return is_range_path(&path) && span_is_range_literal(&expr.span);
+                }
+            }
             // `..` desugars to its struct path
             ExprKind::Path(QPath::Resolved(None, ref path)) => {
                 return is_range_path(&path) && span_is_range_literal(&expr.span);
@@ -454,12 +463,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         false
     }
 
-    pub fn check_for_cast(&self,
-                      err: &mut DiagnosticBuilder<'tcx>,
-                      expr: &hir::Expr,
-                      checked_ty: Ty<'tcx>,
-                      expected_ty: Ty<'tcx>)
-                      -> bool {
+    pub fn check_for_cast(
+        &self,
+        err: &mut DiagnosticBuilder<'tcx>,
+        expr: &hir::Expr,
+        checked_ty: Ty<'tcx>,
+        expected_ty: Ty<'tcx>,
+    ) -> bool {
         let parent_id = self.tcx.hir().get_parent_node(expr.id);
         if let Some(parent) = self.tcx.hir().find(parent_id) {
             // Shouldn't suggest `.into()` on `const`s.
@@ -487,17 +497,40 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // For now, don't suggest casting with `as`.
         let can_cast = false;
 
+        let mut prefix = String::new();
+        if let Some(hir::Node::Expr(hir::Expr {
+            node: hir::ExprKind::Struct(_, fields, _),
+            ..
+        })) = self.tcx.hir().find(self.tcx.hir().get_parent_node(expr.id)) {
+            // `expr` is a literal field for a struct, only suggest if appropriate
+            for field in fields {
+                if field.expr.id == expr.id && field.is_shorthand {
+                    // This is a field literal
+                    prefix = format!("{}: ", field.ident);
+                    break;
+                }
+            }
+            if &prefix == "" {
+                // Likely a field was meant, but this field wasn't found. Do not suggest anything.
+                return false;
+            }
+        }
+
         let needs_paren = expr.precedence().order() < (PREC_POSTFIX as i8);
 
         if let Ok(src) = self.tcx.sess.source_map().span_to_snippet(expr.span) {
             let msg = format!("you can cast an `{}` to `{}`", checked_ty, expected_ty);
-            let cast_suggestion = format!("{}{}{} as {}",
-                                          if needs_paren { "(" } else { "" },
-                                          src,
-                                          if needs_paren { ")" } else { "" },
-                                          expected_ty);
+            let cast_suggestion = format!(
+                "{}{}{}{} as {}",
+                prefix,
+                if needs_paren { "(" } else { "" },
+                src,
+                if needs_paren { ")" } else { "" },
+                expected_ty,
+            );
             let into_suggestion = format!(
-                "{}{}{}.into()",
+                "{}{}{}{}.into()",
+                prefix,
                 if needs_paren { "(" } else { "" },
                 src,
                 if needs_paren { ")" } else { "" },
@@ -534,7 +567,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     if needs_paren { ")" } else { "" },
                 );
 
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     expr.span,
                     &suggest_msg,
                     if literal_is_ty_suffixed(expr) {
@@ -551,7 +584,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     match (found.bit_width(), exp.bit_width()) {
                         (Some(found), Some(exp)) if found > exp => {
                             if can_cast {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_truncate),
                                     cast_suggestion,
@@ -561,7 +594,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         }
                         (None, _) | (_, None) => {
                             if can_cast {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_isize),
                                     cast_suggestion,
@@ -582,7 +615,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     match (found.bit_width(), exp.bit_width()) {
                         (Some(found), Some(exp)) if found > exp => {
                             if can_cast {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_truncate),
                                     cast_suggestion,
@@ -592,7 +625,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         }
                         (None, _) | (_, None) => {
                             if can_cast {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_usize),
                                     cast_suggestion,
@@ -613,7 +646,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     if can_cast {
                         match (found.bit_width(), exp.bit_width()) {
                             (Some(found), Some(exp)) if found > exp - 1 => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_truncate),
                                     cast_suggestion,
@@ -621,7 +654,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (None, None) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_truncate),
                                     cast_suggestion,
@@ -629,7 +662,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (None, _) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_isize),
                                     cast_suggestion,
@@ -637,7 +670,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (_, None) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_usize),
                                     cast_suggestion,
@@ -645,7 +678,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             _ => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_zero_extend),
                                     cast_suggestion,
@@ -660,7 +693,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     if can_cast {
                         match (found.bit_width(), exp.bit_width()) {
                             (Some(found), Some(exp)) if found - 1 > exp => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_truncate),
                                     cast_suggestion,
@@ -668,7 +701,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (None, None) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_sign_extend),
                                     cast_suggestion,
@@ -676,7 +709,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (None, _) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_usize),
                                     cast_suggestion,
@@ -684,7 +717,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             (_, None) => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, depending_on_isize),
                                     cast_suggestion,
@@ -692,7 +725,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 );
                             }
                             _ => {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     expr.span,
                                     &format!("{}, which {}", msg, will_sign_extend),
                                     cast_suggestion,
@@ -710,7 +743,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                            None,
                        );
                     } else if can_cast {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("{}, producing the closest possible value", msg),
                             cast_suggestion,
@@ -721,7 +754,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
                 (&ty::Uint(_), &ty::Float(_)) | (&ty::Int(_), &ty::Float(_)) => {
                     if can_cast {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("{}, rounding the float towards zero", msg),
                             cast_suggestion,
@@ -736,7 +769,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 (&ty::Float(ref exp), &ty::Uint(ref found)) => {
                     // if `found` is `None` (meaning found is `usize`), don't suggest `.into()`
                     if exp.bit_width() > found.bit_width().unwrap_or(256) {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("{}, producing the floating point representation of the \
                                       integer",
@@ -745,7 +778,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             Applicability::MachineApplicable
                         );
                     } else if can_cast {
-                        err.span_suggestion_with_applicability(expr.span,
+                        err.span_suggestion(
+                            expr.span,
                             &format!("{}, producing the floating point representation of the \
                                       integer, rounded if necessary",
                                      msg),
@@ -758,7 +792,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 (&ty::Float(ref exp), &ty::Int(ref found)) => {
                     // if `found` is `None` (meaning found is `isize`), don't suggest `.into()`
                     if exp.bit_width() > found.bit_width().unwrap_or(256) {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("{}, producing the floating point representation of the \
                                       integer",
@@ -767,7 +801,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             Applicability::MachineApplicable
                         );
                     } else if can_cast {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("{}, producing the floating point representation of the \
                                       integer, rounded if necessary",
diff --git a/src/librustc_typeck/check/dropck.rs b/src/librustc_typeck/check/dropck.rs
index 60b5db0d12cc4..ad74e78fecdcd 100644
--- a/src/librustc_typeck/check/dropck.rs
+++ b/src/librustc_typeck/check/dropck.rs
@@ -1,18 +1,18 @@
-use check::regionck::RegionCtxt;
+use crate::check::regionck::RegionCtxt;
 
-use hir::def_id::DefId;
+use crate::hir;
+use crate::hir::def_id::DefId;
 use rustc::infer::outlives::env::OutlivesEnvironment;
 use rustc::infer::{self, InferOk, SuppressRegionErrors};
 use rustc::middle::region;
 use rustc::traits::{ObligationCause, TraitEngine, TraitEngineExt};
 use rustc::ty::subst::{Subst, Substs, UnpackedKind};
 use rustc::ty::{self, Ty, TyCtxt};
-use util::common::ErrorReported;
+use crate::util::common::ErrorReported;
 
-use syntax::ast;
 use syntax_pos::Span;
 
-/// check_drop_impl confirms that the Drop implementation identified by
+/// This function confirms that the `Drop` implementation identified by
 /// `drop_impl_did` is not any more specialized than the type it is
 /// attached to (Issue #8142).
 ///
@@ -21,7 +21,7 @@ use syntax_pos::Span;
 /// 1. The self type must be nominal (this is already checked during
 ///    coherence),
 ///
-/// 2. The generic region/type parameters of the impl's self-type must
+/// 2. The generic region/type parameters of the impl's self type must
 ///    all be parameters of the Drop impl itself (i.e., no
 ///    specialization like `impl Drop for Foo<i32>`), and,
 ///
@@ -70,7 +70,7 @@ fn ensure_drop_params_and_item_params_correspond<'a, 'tcx>(
     drop_impl_ty: Ty<'tcx>,
     self_type_did: DefId,
 ) -> Result<(), ErrorReported> {
-    let drop_impl_node_id = tcx.hir().as_local_node_id(drop_impl_did).unwrap();
+    let drop_impl_hir_id = tcx.hir().as_local_hir_id(drop_impl_did).unwrap();
 
     // check that the impl type can be made to match the trait type.
 
@@ -85,7 +85,7 @@ fn ensure_drop_params_and_item_params_correspond<'a, 'tcx>(
         let fresh_impl_substs = infcx.fresh_substs_for_item(drop_impl_span, drop_impl_did);
         let fresh_impl_self_ty = drop_impl_ty.subst(tcx, fresh_impl_substs);
 
-        let cause = &ObligationCause::misc(drop_impl_span, drop_impl_node_id);
+        let cause = &ObligationCause::misc(drop_impl_span, drop_impl_hir_id);
         match infcx
             .at(cause, impl_param_env)
             .eq(named_type, fresh_impl_self_ty)
@@ -184,7 +184,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'a, 'tcx>(
     // absent. So we report an error that the Drop impl injected a
     // predicate that is not present on the struct definition.
 
-    let self_type_node_id = tcx.hir().as_local_node_id(self_type_did).unwrap();
+    let self_type_hir_id = tcx.hir().as_local_hir_id(self_type_did).unwrap();
 
     let drop_impl_span = tcx.def_span(drop_impl_did);
 
@@ -216,7 +216,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'a, 'tcx>(
         // repeated `contains` calls.
 
         if !assumptions_in_impl_context.contains(&predicate) {
-            let item_span = tcx.hir().span(self_type_node_id);
+            let item_span = tcx.hir().span_by_hir_id(self_type_hir_id);
             struct_span_err!(
                 tcx.sess,
                 drop_impl_span,
@@ -236,9 +236,9 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'a, 'tcx>(
     result
 }
 
-/// check_safety_of_destructor_if_necessary confirms that the type
+/// This function confirms that the type
 /// expression `typ` conforms to the "Drop Check Rule" from the Sound
-/// Generic Drop (RFC 769).
+/// Generic Drop RFC (#769).
 ///
 /// ----
 ///
@@ -276,7 +276,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'a, 'tcx>(
 /// expected to break the needed parametricity property beyond
 /// repair.)
 ///
-/// Therefore we have scaled back Drop-Check to a more conservative
+/// Therefore, we have scaled back Drop-Check to a more conservative
 /// rule that does not attempt to deduce whether a `Drop`
 /// implementation could not possible access data of a given lifetime;
 /// instead Drop-Check now simply assumes that if a destructor has
@@ -287,12 +287,11 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'a, 'tcx>(
 /// this conservative assumption (and thus assume the obligation of
 /// ensuring that they do not access data nor invoke methods of
 /// values that have been previously dropped).
-///
 pub fn check_safety_of_destructor_if_necessary<'a, 'gcx, 'tcx>(
     rcx: &mut RegionCtxt<'a, 'gcx, 'tcx>,
     ty: Ty<'tcx>,
     span: Span,
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
     scope: region::Scope,
 ) -> Result<(), ErrorReported> {
     debug!("check_safety_of_destructor_if_necessary typ: {:?} scope: {:?}",
diff --git a/src/librustc_typeck/check/generator_interior.rs b/src/librustc_typeck/check/generator_interior.rs
index 225fa1dc4f45c..7f4b0a96a15ab 100644
--- a/src/librustc_typeck/check/generator_interior.rs
+++ b/src/librustc_typeck/check/generator_interior.rs
@@ -11,7 +11,7 @@ use rustc::ty::{self, Ty};
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::Span;
 use super::FnCtxt;
-use util::nodemap::FxHashMap;
+use crate::util::nodemap::FxHashMap;
 
 struct InteriorVisitor<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 143715dff813b..fca9fa0829f72 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -4,7 +4,7 @@
 use rustc::traits::{ObligationCause, ObligationCauseCode};
 use rustc::ty::{self, TyCtxt, Ty};
 use rustc::ty::subst::Subst;
-use require_same_types;
+use crate::require_same_types;
 
 use rustc_target::spec::abi::Abi;
 use syntax::symbol::Symbol;
@@ -58,16 +58,17 @@ fn equate_intrinsic_type<'a, 'tcx>(
         safety,
         abi
     )));
-    let cause = ObligationCause::new(it.span, it.id, ObligationCauseCode::IntrinsicType);
+    let cause = ObligationCause::new(it.span, it.hir_id, ObligationCauseCode::IntrinsicType);
     require_same_types(tcx, &cause, tcx.mk_fn_ptr(tcx.fn_sig(def_id)), fty);
 }
 
-/// Returns whether the given intrinsic is unsafe to call or not.
+/// Returns `true` if the given intrinsic is unsafe to call or not.
 pub fn intrisic_operation_unsafety(intrinsic: &str) -> hir::Unsafety {
     match intrinsic {
         "size_of" | "min_align_of" | "needs_drop" |
         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" |
         "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
+        "saturating_add" | "saturating_sub" |
         "rotate_left" | "rotate_right" |
         "ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse"
         => hir::Unsafety::Normal,
@@ -307,6 +308,8 @@ pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 
             "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
                 (1, vec![param(0), param(0)], param(0)),
+            "saturating_add" | "saturating_sub" =>
+                (1, vec![param(0), param(0)], param(0)),
             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
                 (1, vec![param(0), param(0)], param(0)),
 
@@ -430,6 +433,7 @@ pub fn check_platform_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         "simd_insert" => (2, vec![param(0), tcx.types.u32, param(1)], param(0)),
         "simd_extract" => (2, vec![param(0), tcx.types.u32], param(1)),
         "simd_cast" => (2, vec![param(0)], param(1)),
+        "simd_bitmask" => (2, vec![param(0)], param(1)),
         "simd_select" |
         "simd_select_bitmask" => (2, vec![param(0), param(1), param(1)], param(1)),
         "simd_reduce_all" | "simd_reduce_any" => (1, vec![param(0)], tcx.types.bool),
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index 2cf2974a45a1c..34b248a106cb0 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -1,9 +1,9 @@
 use super::{probe, MethodCallee};
 
-use astconv::AstConv;
-use check::{FnCtxt, PlaceOp, callee, Needs};
-use hir::GenericArg;
-use hir::def_id::DefId;
+use crate::astconv::AstConv;
+use crate::check::{FnCtxt, PlaceOp, callee, Needs};
+use crate::hir::GenericArg;
+use crate::hir::def_id::DefId;
 use rustc::ty::subst::Substs;
 use rustc::traits;
 use rustc::ty::{self, Ty, GenericParamDefKind};
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 02687df6a94fc..259a28645815f 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -10,9 +10,9 @@ pub use self::MethodError::*;
 pub use self::CandidateSource::*;
 pub use self::suggest::{SelfSource, TraitInfo};
 
-use check::FnCtxt;
+use crate::check::FnCtxt;
+use crate::namespace::Namespace;
 use errors::{Applicability, DiagnosticBuilder};
-use namespace::Namespace;
 use rustc_data_structures::sync::Lrc;
 use rustc::hir;
 use rustc::hir::def::Def;
@@ -29,7 +29,7 @@ use syntax_pos::Span;
 use crate::{check_type_alias_enum_variants_enabled};
 use self::probe::{IsSuggestion, ProbeScope};
 
-pub fn provide(providers: &mut ty::query::Providers) {
+pub fn provide(providers: &mut ty::query::Providers<'_>) {
     suggest::provide(providers);
     probe::provide(providers);
 }
@@ -124,7 +124,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Add a suggestion to call the given method to the provided diagnostic.
+    /// Adds a suggestion to call the given method to the provided diagnostic.
     crate fn suggest_method_call(
         &self,
         err: &mut DiagnosticBuilder<'a>,
@@ -157,7 +157,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             (format!("{}()", method_name), Applicability::MaybeIncorrect)
         };
 
-        err.span_suggestion_with_applicability(method_name.span, msg, suggestion, applicability);
+        err.span_suggestion(method_name.span, msg, suggestion, applicability);
     }
 
     /// Performs method lookup. If lookup is successful, it will return the callee
@@ -261,12 +261,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     /// `lookup_method_in_trait` is used for overloaded operators.
     /// It does a very narrow slice of what the normal probe/confirm path does.
     /// In particular, it doesn't really do any probing: it simply constructs
-    /// an obligation for a particular trait with the given self-type and checks
+    /// an obligation for a particular trait with the given self type and checks
     /// whether that trait is implemented.
-    ///
-    /// FIXME(#18741): it seems likely that we can consolidate some of this
-    /// code with the other method-lookup code. In particular, the second half
-    /// of this method is basically the same as confirmation.
+    //
+    // FIXME(#18741): it seems likely that we can consolidate some of this
+    // code with the other method-lookup code. In particular, the second half
+    // of this method is basically the same as confirmation.
     pub fn lookup_method_in_trait(&self,
                                   span: Span,
                                   m_name: ast::Ident,
@@ -408,48 +408,39 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         let tcx = self.tcx;
 
-        let mode = probe::Mode::Path;
-        match self.probe_for_name(span, mode, method_name, IsSuggestion(false),
-                                  self_ty, expr_id, ProbeScope::TraitsInScope) {
-            Ok(pick) => {
-                debug!("resolve_ufcs: pick={:?}", pick);
-                if let Some(import_id) = pick.import_id {
-                    let import_def_id = tcx.hir().local_def_id(import_id);
-                    debug!("resolve_ufcs: used_trait_import: {:?}", import_def_id);
-                    Lrc::get_mut(&mut self.tables.borrow_mut().used_trait_imports)
-                                                .unwrap().insert(import_def_id);
+        // Check if we have an enum variant.
+        if let ty::Adt(adt_def, _) = self_ty.sty {
+            if adt_def.is_enum() {
+                let variant_def = adt_def.variants.iter().find(|vd| {
+                    tcx.hygienic_eq(method_name, vd.ident, adt_def.did)
+                });
+                if let Some(variant_def) = variant_def {
+                    check_type_alias_enum_variants_enabled(tcx, span);
+
+                    let def = Def::VariantCtor(variant_def.did, variant_def.ctor_kind);
+                    tcx.check_stability(def.def_id(), Some(expr_id), span);
+                    return Ok(def);
                 }
-
-                let def = pick.item.def();
-                debug!("resolve_ufcs: def={:?}", def);
-                tcx.check_stability(def.def_id(), Some(expr_id), span);
-
-                Ok(def)
             }
-            Err(err) => {
-                // Check if we have an enum variant.
-                match self_ty.sty {
-                    ty::Adt(adt_def, _) if adt_def.is_enum() => {
-                        let variant_def = adt_def.variants.iter().find(|vd| {
-                            tcx.hygienic_eq(method_name, vd.ident, adt_def.did)
-                        });
-                        if let Some(variant_def) = variant_def {
-                            check_type_alias_enum_variants_enabled(tcx, span);
-
-                            let def = Def::VariantCtor(variant_def.did, variant_def.ctor_kind);
-                            tcx.check_stability(def.def_id(), Some(expr_id), span);
-                            return Ok(def);
-                        }
-                    },
-                    _ => (),
-                }
+        }
 
-                Err(err)
-            }
+        let pick = self.probe_for_name(span, probe::Mode::Path, method_name, IsSuggestion(false),
+                                       self_ty, expr_id, ProbeScope::TraitsInScope)?;
+        debug!("resolve_ufcs: pick={:?}", pick);
+        if let Some(import_id) = pick.import_id {
+            let import_def_id = tcx.hir().local_def_id(import_id);
+            debug!("resolve_ufcs: used_trait_import: {:?}", import_def_id);
+            Lrc::get_mut(&mut self.tables.borrow_mut().used_trait_imports)
+                .unwrap().insert(import_def_id);
         }
+
+        let def = pick.item.def();
+        debug!("resolve_ufcs: def={:?}", def);
+        tcx.check_stability(def.def_id(), Some(expr_id), span);
+        Ok(def)
     }
 
-    /// Find item with name `item_name` defined in impl/trait `def_id`
+    /// Finds item with name `item_name` defined in impl/trait `def_id`
     /// and return it, or `None`, if no such item was defined there.
     pub fn associated_item(&self, def_id: DefId, item_name: ast::Ident, ns: Namespace)
                            -> Option<ty::AssociatedItem> {
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 9a828ce01775c..709177212ada7 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -3,11 +3,11 @@ use super::NoMatchData;
 use super::{CandidateSource, ImplSource, TraitSource};
 use super::suggest;
 
-use check::autoderef::{self, Autoderef};
-use check::FnCtxt;
-use hir::def_id::DefId;
-use hir::def::Def;
-use namespace::Namespace;
+use crate::check::autoderef::{self, Autoderef};
+use crate::check::FnCtxt;
+use crate::hir::def_id::DefId;
+use crate::hir::def::Def;
+use crate::namespace::Namespace;
 
 use rustc_data_structures::sync::Lrc;
 use rustc::hir;
@@ -85,6 +85,37 @@ impl<'a, 'gcx, 'tcx> Deref for ProbeContext<'a, 'gcx, 'tcx> {
 
 #[derive(Debug)]
 struct Candidate<'tcx> {
+    // Candidates are (I'm not quite sure, but they are mostly) basically
+    // some metadata on top of a `ty::AssociatedItem` (without substs).
+    //
+    // However, method probing wants to be able to evaluate the predicates
+    // for a function with the substs applied - for example, if a function
+    // has `where Self: Sized`, we don't want to consider it unless `Self`
+    // is actually `Sized`, and similarly, return-type suggestions want
+    // to consider the "actual" return type.
+    //
+    // The way this is handled is through `xform_self_ty`. It contains
+    // the receiver type of this candidate, but `xform_self_ty`,
+    // `xform_ret_ty` and `kind` (which contains the predicates) have the
+    // generic parameters of this candidate substituted with the *same set*
+    // of inference variables, which acts as some weird sort of "query".
+    //
+    // When we check out a candidate, we require `xform_self_ty` to be
+    // a subtype of the passed-in self-type, and this equates the type
+    // variables in the rest of the fields.
+    //
+    // For example, if we have this candidate:
+    // ```
+    //    trait Foo {
+    //        fn foo(&self) where Self: Sized;
+    //    }
+    // ```
+    //
+    // Then `xform_self_ty` will be `&'erased ?X` and `kind` will contain
+    // the predicate `?X: Sized`, so if we are evaluating `Foo` for a
+    // the receiver `&T`, we'll do the subtyping which will make `?X`
+    // get the right value, then when we evaluate the predicate we'll check
+    // if `T: Sized`.
     xform_self_ty: Ty<'tcx>,
     xform_ret_ty: Option<Ty<'tcx>>,
     item: ty::AssociatedItem,
@@ -370,7 +401,7 @@ fn method_autoderef_steps<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
     tcx.infer_ctxt().enter_with_canonical(DUMMY_SP, &goal, |ref infcx, goal, inference_vars| {
         let ParamEnvAnd { param_env, value: self_ty } = goal;
 
-        let mut autoderef = Autoderef::new(infcx, param_env, ast::DUMMY_NODE_ID, DUMMY_SP, self_ty)
+        let mut autoderef = Autoderef::new(infcx, param_env, hir::DUMMY_HIR_ID, DUMMY_SP, self_ty)
             .include_raw_pointers()
             .silence_errors();
         let mut reached_raw_pointer = false;
@@ -506,15 +537,28 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         match self_ty.value.value.sty {
             ty::Dynamic(ref data, ..) => {
                 if let Some(p) = data.principal() {
-                    self.fcx.probe(|_| {
-                        let InferOk { value: self_ty, obligations: _ } =
-                            self.fcx.probe_instantiate_query_response(
-                                self.span, &self.orig_steps_var_values, self_ty)
-                            .unwrap_or_else(|_| {
-                                span_bug!(self.span, "{:?} was applicable but now isn't?", self_ty)
-                            });
-                        self.assemble_inherent_candidates_from_object(self_ty);
-                    });
+                    // Subtle: we can't use `instantiate_query_response` here: using it will
+                    // commit to all of the type equalities assumed by inference going through
+                    // autoderef (see the `method-probe-no-guessing` test).
+                    //
+                    // However, in this code, it is OK if we end up with an object type that is
+                    // "more general" than the object type that we are evaluating. For *every*
+                    // object type `MY_OBJECT`, a function call that goes through a trait-ref
+                    // of the form `<MY_OBJECT as SuperTraitOf(MY_OBJECT)>::func` is a valid
+                    // `ObjectCandidate`, and it should be discoverable "exactly" through one
+                    // of the iterations in the autoderef loop, so there is no problem with it
+                    // being discoverable in another one of these iterations.
+                    //
+                    // Using `instantiate_canonical_with_fresh_inference_vars` on our
+                    // `Canonical<QueryResponse<Ty<'tcx>>>` and then *throwing away* the
+                    // `CanonicalVarValues` will exactly give us such a generalization - it
+                    // will still match the original object type, but it won't pollute our
+                    // type variables in any form, so just do that!
+                    let (QueryResponse { value: generalized_self_ty, .. }, _ignored_var_values) =
+                        self.fcx.instantiate_canonical_with_fresh_inference_vars(
+                            self.span, &self_ty);
+
+                    self.assemble_inherent_candidates_from_object(generalized_self_ty);
                     self.assemble_inherent_impl_candidates_for_type(p.def_id());
                 }
             }
@@ -1139,14 +1183,14 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         stable_pick: &Pick,
         unstable_candidates: &[(&Candidate<'tcx>, Symbol)],
     ) {
-        let mut diag = self.tcx.struct_span_lint_node(
+        let mut diag = self.tcx.struct_span_lint_hir(
             lint::builtin::UNSTABLE_NAME_COLLISIONS,
             self.fcx.body_id,
             self.span,
             "a method with this name may be added to the standard library in the future",
         );
 
-        // FIXME: This should be a `span_suggestion_with_applicability` instead of `help`
+        // FIXME: This should be a `span_suggestion` instead of `help`
         // However `self.span` only
         // highlights the method name, so we can't use it. Also consider reusing the code from
         // `report_method_error()`.
@@ -1493,7 +1537,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Get the type of an impl and generate substitutions with placeholders.
+    /// Gets the type of an impl and generate substitutions with placeholders.
     fn impl_ty_and_substs(&self, impl_def_id: DefId) -> (Ty<'tcx>, &'tcx Substs<'tcx>) {
         (self.tcx.type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
     }
@@ -1510,7 +1554,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// Replace late-bound-regions bound by `value` with `'static` using
+    /// Replaces late-bound-regions bound by `value` with `'static` using
     /// `ty::erase_late_bound_regions`.
     ///
     /// This is only a reasonable thing to do during the *probe* phase, not the *confirm* phase, of
@@ -1534,7 +1578,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
         self.tcx.erase_late_bound_regions(value)
     }
 
-    /// Find the method with the appropriate name (or return type, as the case may be). If
+    /// Finds the method with the appropriate name (or return type, as the case may be). If
     /// `allow_similar_names` is set, find methods with close-matching names.
     fn impl_or_trait_item(&self, def_id: DefId) -> Vec<ty::AssociatedItem> {
         if let Some(name) = self.method_name {
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 23bcd88d6afb5..768842ef39214 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -1,10 +1,11 @@
 //! Give useful errors and suggestions to users when an item can't be
 //! found or is otherwise invalid.
 
-use check::FnCtxt;
+use crate::check::FnCtxt;
+use crate::middle::lang_items::FnOnceTraitLangItem;
+use crate::namespace::Namespace;
+use crate::util::nodemap::FxHashSet;
 use errors::{Applicability, DiagnosticBuilder};
-use middle::lang_items::FnOnceTraitLangItem;
-use namespace::Namespace;
 use rustc_data_structures::sync::Lrc;
 use rustc::hir::{self, ExprKind, Node, QPath};
 use rustc::hir::def::Def;
@@ -15,7 +16,6 @@ use rustc::infer::type_variable::TypeVariableOrigin;
 use rustc::traits::Obligation;
 use rustc::ty::{self, Adt, Ty, TyCtxt, ToPolyTraitRef, ToPredicate, TypeFoldable};
 use rustc::ty::item_path::with_crate_prefix;
-use util::nodemap::FxHashSet;
 use syntax_pos::{Span, FileName};
 use syntax::ast;
 use syntax::util::lev_distance::find_best_match_for_name;
@@ -237,15 +237,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 let snippet = tcx.sess.source_map().span_to_snippet(lit.span)
                                     .unwrap_or_else(|_| "<numeric literal>".to_owned());
 
-                                err.span_suggestion_with_applicability(
-                                                    lit.span,
-                                                    &format!("you must specify a concrete type for \
-                                                              this numeric value, like `{}`",
-                                                             concrete_type),
-                                                    format!("{}_{}",
-                                                            snippet,
-                                                            concrete_type),
-                                                    Applicability::MaybeIncorrect,
+                                err.span_suggestion(
+                                    lit.span,
+                                    &format!("you must specify a concrete type for \
+                                              this numeric value, like `{}`", concrete_type),
+                                    format!("{}_{}", snippet, concrete_type),
+                                    Applicability::MaybeIncorrect,
                                 );
                             }
                             ExprKind::Path(ref qpath) => {
@@ -271,7 +268,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                                 ty,
                                                 ..
                                             })) => {
-                                                err.span_suggestion_with_applicability(
+                                                err.span_suggestion(
                                                     // account for `let x: _ = 42;`
                                                     //                  ^^^^
                                                     span.to(ty.as_ref().map(|ty| ty.span)
@@ -304,7 +301,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         );
                         if let Some(suggestion) = suggestion {
                             // enum variant
-                            err.help(&format!("did you mean `{}`?", suggestion));
+                            err.span_suggestion(
+                                item_name.span,
+                                "did you mean",
+                                suggestion.to_string(),
+                                Applicability::MaybeIncorrect,
+                            );
                         }
                         err
                     }
@@ -344,7 +346,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                     };
 
                                     let field_ty = field.ty(tcx, substs);
-                                    let scope = self.tcx.hir().get_module_parent(self.body_id);
+                                    let scope = self.tcx.hir().get_module_parent_by_hir_id(
+                                        self.body_id);
                                     if field.vis.is_accessible_from(scope, self.tcx) {
                                         if self.is_fn_ty(&field_ty, span) {
                                             err.help(&format!("use `({0}.{1})(...)` if you \
@@ -399,7 +402,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
                 if static_sources.len() == 1 {
                     if let SelfSource::MethodCall(expr) = source {
-                        err.span_suggestion_with_applicability(expr.span.to(span),
+                        err.span_suggestion(expr.span.to(span),
                                             "use associated function syntax instead",
                                             format!("{}::{}",
                                                     self.ty_to_string(actual),
@@ -440,7 +443,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 }
 
                 if let Some(lev_candidate) = lev_candidate {
-                    err.help(&format!("did you mean `{}`?", lev_candidate.ident));
+                    err.span_suggestion(
+                        span,
+                        "did you mean",
+                        lev_candidate.ident.to_string(),
+                        Applicability::MaybeIncorrect,
+                    );
                 }
                 err.emit();
             }
@@ -492,7 +500,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                               err: &mut DiagnosticBuilder,
                               mut msg: String,
                               candidates: Vec<DefId>) {
-        let module_did = self.tcx.hir().get_module_parent(self.body_id);
+        let module_did = self.tcx.hir().get_module_parent_by_hir_id(self.body_id);
         let module_id = self.tcx.hir().as_local_node_id(module_did).unwrap();
         let krate = self.tcx.hir().krate();
         let (span, found_use) = UsePlacementFinder::check(self.tcx, krate, module_id);
@@ -512,12 +520,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 )
             });
 
-            err.span_suggestions_with_applicability(
-                                                    span,
-                                                    &msg,
-                                                    path_strings,
-                                                    Applicability::MaybeIncorrect,
-            );
+            err.span_suggestions(span, &msg, path_strings, Applicability::MaybeIncorrect);
         } else {
             let limit = if candidates.len() == 5 { 5 } else { 4 };
             for (i, trait_did) in candidates.iter().take(limit).enumerate() {
@@ -707,12 +710,12 @@ impl Ord for TraitInfo {
     }
 }
 
-/// Retrieve all traits in this crate and any dependent crates.
+/// Retrieves all traits in this crate and any dependent crates.
 pub fn all_traits<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Vec<TraitInfo> {
     tcx.all_traits(LOCAL_CRATE).iter().map(|&def_id| TraitInfo { def_id }).collect()
 }
 
-/// Compute all traits in this crate and any dependent crates.
+/// Computes all traits in this crate and any dependent crates.
 fn compute_all_traits<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Vec<DefId> {
     use hir::itemlikevisit;
 
@@ -750,12 +753,11 @@ fn compute_all_traits<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Vec<DefId>
                            traits: &mut Vec<DefId>,
                            external_mods: &mut FxHashSet<DefId>,
                            def: Def) {
-        let def_id = def.def_id();
         match def {
-            Def::Trait(..) => {
+            Def::Trait(def_id) => {
                 traits.push(def_id);
             }
-            Def::Mod(..) => {
+            Def::Mod(def_id) => {
                 if !external_mods.insert(def_id) {
                     return;
                 }
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 1b07385d4d1f4..10f234fd3ca6a 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1,6 +1,6 @@
 /*!
 
-# check.rs
+# typeck: check phase
 
 Within the check phase of type check, we check each item one at a time
 (bodies of function expressions are checked as part of the containing
@@ -83,15 +83,15 @@ mod generator_interior;
 pub mod intrinsic;
 mod op;
 
-use astconv::{AstConv, PathSeg};
+use crate::astconv::{AstConv, PathSeg};
 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
 use rustc::hir::{self, ExprKind, GenericArg, ItemKind, Node, PatKind, QPath};
 use rustc::hir::def::{CtorKind, Def};
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
-use middle::lang_items;
-use namespace::Namespace;
+use crate::middle::lang_items;
+use crate::namespace::Namespace;
 use rustc::infer::{self, InferCtxt, InferOk, InferResult, RegionVariableOrigin};
 use rustc::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
 use rustc_data_structures::indexed_vec::Idx;
@@ -103,13 +103,12 @@ use rustc::middle::region;
 use rustc::mir::interpret::{ConstValue, GlobalId};
 use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
 use rustc::ty::{
-    self, AdtKind, CanonicalUserTypeAnnotation, Ty, TyCtxt, GenericParamDefKind, Visibility,
-    ToPolyTraitRef, ToPredicate, RegionKind, UserTypeAnnotation
+    self, AdtKind, CanonicalUserType, Ty, TyCtxt, GenericParamDefKind, Visibility,
+    ToPolyTraitRef, ToPredicate, RegionKind, UserType
 };
 use rustc::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
 use rustc::ty::fold::TypeFoldable;
 use rustc::ty::query::Providers;
-use rustc::ty::query::queries;
 use rustc::ty::subst::{UnpackedKind, Subst, Substs, UserSelfTy, UserSubsts};
 use rustc::ty::util::{Representability, IntTypeExt, Discr};
 use rustc::ty::layout::VariantIdx;
@@ -131,13 +130,14 @@ use std::mem::replace;
 use std::ops::{self, Deref};
 use std::slice;
 
-use require_c_abi_if_variadic;
-use session::{CompileIncomplete, config, Session};
-use TypeAndSubsts;
-use lint;
-use util::captures::Captures;
-use util::common::{ErrorReported, indenter};
-use util::nodemap::{DefIdMap, DefIdSet, FxHashMap, FxHashSet, NodeMap};
+use crate::require_c_abi_if_variadic;
+use crate::session::{CompileIncomplete, Session};
+use crate::session::config::EntryFnType;
+use crate::TypeAndSubsts;
+use crate::lint;
+use crate::util::captures::Captures;
+use crate::util::common::{ErrorReported, indenter};
+use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashMap, FxHashSet, NodeMap};
 
 pub use self::Expectation::*;
 use self::autoderef::Autoderef;
@@ -154,7 +154,7 @@ pub struct LocalTy<'tcx> {
     revealed_ty: Ty<'tcx>
 }
 
-/// A wrapper for InferCtxt's `in_progress_tables` field.
+/// A wrapper for `InferCtxt`'s `in_progress_tables` field.
 #[derive(Copy, Clone)]
 struct MaybeInProgressTables<'a, 'tcx: 'a> {
     maybe_tables: Option<&'a RefCell<ty::TypeckTables<'tcx>>>,
@@ -180,7 +180,7 @@ impl<'a, 'tcx> MaybeInProgressTables<'a, 'tcx> {
     }
 }
 
-/// closures defined within the function.  For example:
+/// Closures defined within the function. For example:
 ///
 ///     fn foo() {
 ///         bar(move|| { ... })
@@ -249,10 +249,10 @@ pub enum Expectation<'tcx> {
     /// This expression is an `if` condition, it must resolve to `bool`.
     ExpectIfCondition,
 
-    /// This expression should have the type given (or some subtype)
+    /// This expression should have the type given (or some subtype).
     ExpectHasType(Ty<'tcx>),
 
-    /// This expression will be cast to the `Ty`
+    /// This expression will be cast to the `Ty`.
     ExpectCastableToType(Ty<'tcx>),
 
     /// This rvalue expression will be wrapped in `&` or `Box` and coerced
@@ -294,7 +294,7 @@ impl<'a, 'gcx, 'tcx> Expectation<'tcx> {
         }
     }
 
-    /// Provide an expectation for an rvalue expression given an *optional*
+    /// Provides an expectation for an rvalue expression given an *optional*
     /// hint, which is not required for type safety (the resulting type might
     /// be checked higher up, as is the case with `&expr` and `box expr`), but
     /// is useful in determining the concrete type.
@@ -449,7 +449,7 @@ pub enum Diverges {
     Always,
 
     /// Same as `Always` but with a reachability
-    /// warning already emitted
+    /// warning already emitted.
     WarnedAlways
 }
 
@@ -510,7 +510,7 @@ impl<'gcx, 'tcx> EnclosingBreakables<'gcx, 'tcx> {
 }
 
 pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
 
     /// The parameter environment used for proving trait obligations
     /// in this function. This can change when we descend into
@@ -534,16 +534,16 @@ pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     ps: RefCell<UnsafetyState>,
 
     /// Whether the last checked node generates a divergence (e.g.,
-    /// `return` will set this to Always). In general, when entering
+    /// `return` will set this to `Always`). In general, when entering
     /// an expression or other node in the tree, the initial value
     /// indicates whether prior parts of the containing expression may
     /// have diverged. It is then typically set to `Maybe` (and the
     /// old value remembered) for processing the subparts of the
     /// current expression. As each subpart is processed, they may set
-    /// the flag to `Always` etc.  Finally, at the end, we take the
+    /// the flag to `Always`, etc. Finally, at the end, we take the
     /// result and "union" it with the original value, so that when we
     /// return the flag indicates if any subpart of the parent
-    /// expression (up to and including this part) has diverged.  So,
+    /// expression (up to and including this part) has diverged. So,
     /// if you read it after evaluating a subexpression `X`, the value
     /// you get indicates whether any subexpression that was
     /// evaluating up to and including `X` diverged.
@@ -562,7 +562,7 @@ pub struct FnCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     ///   foo();}` or `{return; 22}`, where we would warn on the
     ///   `foo()` or `22`.
     ///
-    /// An expression represents dead-code if, after checking it,
+    /// An expression represents dead code if, after checking it,
     /// the diverges flag is set to something other than `Maybe`.
     diverges: Cell<Diverges>,
 
@@ -581,9 +581,9 @@ impl<'a, 'gcx, 'tcx> Deref for FnCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-/// Helper type of a temporary returned by Inherited::build(...).
+/// Helper type of a temporary returned by `Inherited::build(...)`.
 /// Necessary because we can't write the following bound:
-/// F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(Inherited<'b, 'gcx, 'tcx>).
+/// `F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(Inherited<'b, 'gcx, 'tcx>)`.
 pub struct InheritedBuilder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     infcx: infer::InferCtxtBuilder<'a, 'gcx, 'tcx>,
     def_id: DefId,
@@ -672,7 +672,7 @@ impl<'a, 'gcx, 'tcx> Inherited<'a, 'gcx, 'tcx> {
 
     fn normalize_associated_types_in<T>(&self,
                                         span: Span,
-                                        body_id: ast::NodeId,
+                                        body_id: hir::HirId,
                                         param_env: ty::ParamEnv<'tcx>,
                                         value: &T) -> T
         where T : TypeFoldable<'tcx>
@@ -695,14 +695,14 @@ impl<'a, 'tcx> ItemLikeVisitor<'tcx> for CheckItemTypesVisitor<'a, 'tcx> {
 pub fn check_wf_new<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Result<(), ErrorReported> {
     tcx.sess.track_errors(|| {
         let mut visit = wfcheck::CheckTypeWellFormedVisitor::new(tcx);
-        tcx.hir().krate().visit_all_item_likes(&mut visit.as_deep_visitor());
+        tcx.hir().krate().visit_all_item_likes(&mut visit);
     })
 }
 
 pub fn check_item_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Result<(), ErrorReported> {
     tcx.sess.track_errors(|| {
         for &module in tcx.hir().krate().modules.keys() {
-            queries::check_mod_item_types::ensure(tcx, tcx.hir().local_def_id(module));
+            tcx.ensure().check_mod_item_types(tcx.hir().local_def_id(module));
         }
     })
 }
@@ -721,7 +721,7 @@ fn typeck_item_bodies<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateNum
     debug_assert!(crate_num == LOCAL_CRATE);
     Ok(tcx.sess.track_errors(|| {
         tcx.par_body_owners(|body_owner_def_id| {
-            ty::query::queries::typeck_tables_of::ensure(tcx, body_owner_def_id);
+            tcx.ensure().typeck_tables_of(body_owner_def_id);
         });
     })?)
 }
@@ -760,13 +760,13 @@ fn adt_destructor<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     tcx.calculate_dtor(def_id, &mut dropck::check_drop_impl)
 }
 
-/// If this def-id is a "primary tables entry", returns `Some((body_id, decl))`
+/// If this `DefId` is a "primary tables entry", returns `Some((body_id, decl))`
 /// with information about it's body-id and fn-decl (if any). Otherwise,
 /// returns `None`.
 ///
 /// If this function returns "some", then `typeck_tables(def_id)` will
 /// succeed; if it returns `None`, then `typeck_tables(def_id)` may or
-/// may not succeed.  In some cases where this function returns `None`
+/// may not succeed. In some cases where this function returns `None`
 /// (notably closures), `typeck_tables(def_id)` would wind up
 /// redirecting to the owning function.
 fn primary_body_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -861,14 +861,14 @@ fn typeck_tables_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                 tcx.liberate_late_bound_regions(def_id, &fn_sig);
             let fn_sig =
                 inh.normalize_associated_types_in(body.value.span,
-                                                  body_id.node_id,
+                                                  body_id.hir_id,
                                                   param_env,
                                                   &fn_sig);
 
             let fcx = check_fn(&inh, param_env, fn_sig, decl, id, body, None).0;
             fcx
         } else {
-            let fcx = FnCtxt::new(&inh, param_env, body.value.id);
+            let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
             let expected_type = tcx.type_of(def_id);
             let expected_type = fcx.normalize_associated_types_in(body.value.span, &expected_type);
             fcx.require_type_is_sized(expected_type, body.value.span, traits::ConstSized);
@@ -984,7 +984,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for GatherLocalsVisitor<'a, 'gcx, 'tcx> {
                 };
 
                 let c_ty = self.fcx.inh.infcx.canonicalize_user_type_annotation(
-                    &UserTypeAnnotation::Ty(revealed_ty)
+                    &UserType::Ty(revealed_ty)
                 );
                 debug!("visit_local: ty.hir_id={:?} o_ty={:?} revealed_ty={:?} c_ty={:?}",
                        ty.hir_id, o_ty, revealed_ty, c_ty);
@@ -1005,7 +1005,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for GatherLocalsVisitor<'a, 'gcx, 'tcx> {
 
     // Add pattern bindings.
     fn visit_pat(&mut self, p: &'gcx hir::Pat) {
-        if let PatKind::Binding(_, _, ident, _) = p.node {
+        if let PatKind::Binding(_, _, _, ident, _) = p.node {
             let var_ty = self.assign(p.span, p.id, None);
 
             if !self.fcx.tcx.features().unsized_locals {
@@ -1037,7 +1037,7 @@ struct GeneratorTypes<'tcx> {
     /// Types that are captured (see `GeneratorInterior` for more).
     interior: ty::Ty<'tcx>,
 
-    /// Indicates if the generator is movable or static (immovable)
+    /// Indicates if the generator is movable or static (immovable).
     movability: hir::GeneratorMovability,
 }
 
@@ -1062,7 +1062,7 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
 
     // Create the function context.  This is either derived from scratch or,
     // in the case of closures, based on the outer context.
-    let mut fcx = FnCtxt::new(inherited, param_env, body.value.id);
+    let mut fcx = FnCtxt::new(inherited, param_env, body.value.hir_id);
     *fcx.ps.borrow_mut() = UnsafetyState::function(fn_sig.unsafety, fn_id);
 
     let declared_ret_ty = fn_sig.output();
@@ -1163,19 +1163,19 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
 
     // Check that the main return type implements the termination trait.
     if let Some(term_id) = fcx.tcx.lang_items().termination() {
-        if let Some((id, _, entry_type)) = *fcx.tcx.sess.entry_fn.borrow() {
-            if id == fn_id {
-                if let config::EntryFnType::Main = entry_type {
-                    let substs = fcx.tcx.mk_substs_trait(declared_ret_ty, &[]);
-                    let trait_ref = ty::TraitRef::new(term_id, substs);
-                    let return_ty_span = decl.output.span();
-                    let cause = traits::ObligationCause::new(
-                        return_ty_span, fn_id, ObligationCauseCode::MainFunctionType);
-
-                    inherited.register_predicate(
-                        traits::Obligation::new(
-                            cause, param_env, trait_ref.to_predicate()));
-                }
+        if let Some((def_id, EntryFnType::Main)) = fcx.tcx.entry_fn(LOCAL_CRATE) {
+            let main_id = fcx.tcx.hir().as_local_node_id(def_id).unwrap();
+            if main_id == fn_id {
+                let substs = fcx.tcx.mk_substs_trait(declared_ret_ty, &[]);
+                let trait_ref = ty::TraitRef::new(term_id, substs);
+                let return_ty_span = decl.output.span();
+                let fn_hir_id = fcx.tcx.hir().node_to_hir_id(fn_id);
+                let cause = traits::ObligationCause::new(
+                    return_ty_span, fn_hir_id, ObligationCauseCode::MainFunctionType);
+
+                inherited.register_predicate(
+                    traits::Obligation::new(
+                        cause, param_env, trait_ref.to_predicate()));
             }
         }
     }
@@ -1386,10 +1386,7 @@ pub fn check_item_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, it: &'tcx hir::Ite
         }
         hir::ItemKind::Existential(..) => {
             let def_id = tcx.hir().local_def_id(it.id);
-            let pty_ty = tcx.type_of(def_id);
-            let generics = tcx.generics_of(def_id);
 
-            check_bounds_are_used(tcx, &generics, pty_ty);
             let substs = Substs::identity_for_item(tcx, def_id);
             check_opaque(tcx, def_id, substs, it.span);
         }
@@ -1884,14 +1881,14 @@ pub fn check_enum<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         // Check for duplicate discriminant values
         if let Some(i) = disr_vals.iter().position(|&x| x.val == discr.val) {
             let variant_did = def.variants[VariantIdx::new(i)].did;
-            let variant_i_node_id = tcx.hir().as_local_node_id(variant_did).unwrap();
-            let variant_i = tcx.hir().expect_variant(variant_i_node_id);
+            let variant_i_hir_id = tcx.hir().as_local_hir_id(variant_did).unwrap();
+            let variant_i = tcx.hir().expect_variant(variant_i_hir_id);
             let i_span = match variant_i.node.disr_expr {
-                Some(ref expr) => tcx.hir().span(expr.id),
-                None => tcx.hir().span(variant_i_node_id)
+                Some(ref expr) => tcx.hir().span_by_hir_id(expr.hir_id),
+                None => tcx.hir().span_by_hir_id(variant_i_hir_id)
             };
             let span = match v.node.disr_expr {
-                Some(ref expr) => tcx.hir().span(expr.id),
+                Some(ref expr) => tcx.hir().span_by_hir_id(expr.hir_id),
                 None => v.span
             };
             struct_span_err!(tcx.sess, span, E0081,
@@ -2023,7 +2020,7 @@ enum TupleArgumentsFlag {
 impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn new(inh: &'a Inherited<'a, 'gcx, 'tcx>,
                param_env: ty::ParamEnv<'tcx>,
-               body_id: ast::NodeId)
+               body_id: hir::HirId)
                -> FnCtxt<'a, 'gcx, 'tcx> {
         FnCtxt {
             body_id,
@@ -2052,7 +2049,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         self.tcx.sess.err_count() - self.err_count_on_creation
     }
 
-    /// Produce warning on the given node, if the current point in the
+    /// Produces warning on the given node, if the current point in the
     /// function is unreachable, and there hasn't been another warning.
     fn warn_if_unreachable(&self, id: ast::NodeId, span: Span, kind: &str) {
         if self.diverges.get() == Diverges::Always {
@@ -2194,7 +2191,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         user_self_ty: None, // not relevant here
                     };
 
-                    self.infcx.canonicalize_user_type_annotation(&UserTypeAnnotation::TypeOf(
+                    self.infcx.canonicalize_user_type_annotation(&UserType::TypeOf(
                         method.def_id,
                         user_substs,
                     ))
@@ -2239,7 +2236,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
         if !substs.is_noop() {
             let canonicalized = self.infcx.canonicalize_user_type_annotation(
-                &UserTypeAnnotation::TypeOf(def_id, UserSubsts {
+                &UserType::TypeOf(def_id, UserSubsts {
                     substs,
                     user_self_ty,
                 })
@@ -2252,7 +2249,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn write_user_type_annotation(
         &self,
         hir_id: hir::HirId,
-        canonical_user_type_annotation: CanonicalUserTypeAnnotation<'tcx>,
+        canonical_user_type_annotation: CanonicalUserType<'tcx>,
     ) {
         debug!(
             "write_user_type_annotation: hir_id={:?} canonical_user_type_annotation={:?} tag={}",
@@ -2337,7 +2334,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         result
     }
 
-    /// Replace the opaque types from the given value with type variables,
+    /// Replaces the opaque types from the given value with type variables,
     /// and records the `OpaqueTypeMap` for later use during writeback. See
     /// `InferCtxt::instantiate_opaque_types` for more details.
     fn instantiate_opaque_types_from_value<T: TypeFoldable<'tcx>>(
@@ -2437,10 +2434,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // types that involve projections, since those can resolve to
         // `'static` bounds (modulo #54940, which hopefully will be
         // fixed by the time you see this comment, dear reader,
-        // although I have my doubts). Other sorts of things are
-        // already sufficiently enforced with erased regions. =)
-        if ty.has_free_regions() || ty.has_projections() {
-            let c_ty = self.infcx.canonicalize_response(&UserTypeAnnotation::Ty(ty));
+        // although I have my doubts). Also pass in types with inference
+        // types, because they may be repeated. Other sorts of things
+        // are already sufficiently enforced with erased regions. =)
+        if ty.has_free_regions() || ty.has_projections() || ty.has_infer_types() {
+            let c_ty = self.infcx.canonicalize_response(&UserType::Ty(ty));
             debug!("to_ty_saving_user_provided_ty: c_ty={:?}", c_ty);
             self.tables.borrow_mut().user_provided_types_mut().insert(ast_ty.hir_id, c_ty);
         }
@@ -2902,7 +2900,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 let sugg_span = tcx.sess.source_map().end_point(expr_sp);
                 // remove closing `)` from the span
                 let sugg_span = sugg_span.shrink_to_lo();
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     sugg_span,
                     "expected the unit value `()`; create it with empty parentheses",
                     String::from("()"),
@@ -3044,7 +3042,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         // arguments which we skipped above.
         if variadic {
             fn variadic_error<'tcx>(s: &Session, span: Span, t: Ty<'tcx>, cast_ty: &str) {
-                use structured_errors::{VariadicError, StructuredDiagnostic};
+                use crate::structured_errors::{VariadicError, StructuredDiagnostic};
                 VariadicError::new(s, span, t, cast_ty).diagnostic().emit();
             }
 
@@ -3121,7 +3119,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 opt_ty.unwrap_or_else(
                     || tcx.mk_float_var(self.next_float_var_id()))
             }
-            ast::LitKind::Bool(_) => tcx.types.bool
+            ast::LitKind::Bool(_) => tcx.types.bool,
+            ast::LitKind::Err(_) => tcx.types.err,
         }
     }
 
@@ -3168,7 +3167,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     self.tcx.sess.source_map().span_to_snippet(lhs.span),
                     self.tcx.sess.source_map().span_to_snippet(rhs.span))
                 {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         expr.span,
                         msg,
                         format!("{} == {}", left, right),
@@ -3585,7 +3584,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         if let Some(suggested_field_name) =
                             Self::suggest_field_name(def.non_enum_variant(),
                                                      &field.as_str(), vec![]) {
-                                err.span_suggestion_with_applicability(
+                                err.span_suggestion(
                                     field.span,
                                     "a field with a similar name exists",
                                     suggested_field_name.to_string(),
@@ -3616,7 +3615,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             } else {
                                 Applicability::MaybeIncorrect
                             };
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 expr.span, help, suggestion, applicability
                             );
                         }
@@ -3627,7 +3626,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                             .unwrap_or_else(|_| self.tcx.hir().node_to_pretty_string(base.id));
                         let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
                         let suggestion = format!("(*{}).{}", base, field);
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &msg,
                             suggestion,
@@ -3684,8 +3683,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         display
     }
 
-    fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS)
-        -> DiagnosticBuilder {
+    fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
+        -> DiagnosticBuilder<'_> {
         type_error_struct!(self.tcx().sess, span, expr_t, E0609,
                            "no field `{}` on type `{}`",
                            field, expr_t)
@@ -3717,12 +3716,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         if let Some(field_name) = Self::suggest_field_name(variant,
                                                            &field.ident.as_str(),
                                                            skip_fields.collect()) {
-            err.span_suggestion_with_applicability(
-                    field.ident.span,
-                    "a field with a similar name exists",
-                    field_name.to_string(),
-                    Applicability::MaybeIncorrect,
-                );
+            err.span_suggestion(
+                field.ident.span,
+                "a field with a similar name exists",
+                field_name.to_string(),
+                Applicability::MaybeIncorrect,
+            );
         } else {
             match ty.sty {
                 ty::Adt(adt, ..) => {
@@ -4347,11 +4346,15 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     struct_span_err!(self.tcx.sess, expr.span, E0572,
                                      "return statement outside of function body").emit();
                 } else if let Some(ref e) = *expr_opt {
-                    *self.ret_coercion_span.borrow_mut() = Some(e.span);
+                    if self.ret_coercion_span.borrow().is_none() {
+                        *self.ret_coercion_span.borrow_mut() = Some(e.span);
+                    }
                     self.check_return_expr(e);
                 } else {
                     let mut coercion = self.ret_coercion.as_ref().unwrap().borrow_mut();
-                    *self.ret_coercion_span.borrow_mut() = Some(expr.span);
+                    if self.ret_coercion_span.borrow().is_none() {
+                        *self.ret_coercion_span.borrow_mut() = Some(expr.span);
+                    }
                     let cause = self.cause(expr.span, ObligationCauseCode::ReturnNoExpression);
                     if let Some((fn_decl, _)) = self.get_fn_decl(expr.id) {
                         coercion.coerce_forced_unit(
@@ -4592,7 +4595,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 if element_ty.references_error() {
                     tcx.types.err
                 } else if let Ok(count) = count {
-                    tcx.mk_ty(ty::Array(t, tcx.intern_lazy_const(ty::LazyConst::Evaluated(count))))
+                    tcx.mk_ty(ty::Array(t, tcx.mk_lazy_const(ty::LazyConst::Evaluated(count))))
                 } else {
                     tcx.types.err
                 }
@@ -4664,11 +4667,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                             ast::LitIntType::Unsuffixed) = lit.node {
                                         let snip = tcx.sess.source_map().span_to_snippet(base.span);
                                         if let Ok(snip) = snip {
-                                            err.span_suggestion_with_applicability(
+                                            err.span_suggestion(
                                                 expr.span,
                                                 "to access tuple elements, use",
                                                 format!("{}.{}", snip, i),
-                                                Applicability::MachineApplicable);
+                                                Applicability::MachineApplicable,
+                                            );
                                             needs_note = false;
                                         }
                                     }
@@ -4724,8 +4728,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 } else {
                     Def::Err
                 };
-                let (ty, def) = AstConv::associated_path_def_to_ty(self, node_id, path_span,
-                                                                   ty, def, segment);
+                let (ty, def) = AstConv::associated_path_to_ty(self, node_id, path_span,
+                                                               ty, def, segment, true);
 
                 // Write back the new resolution.
                 let hir_id = self.tcx.hir().node_to_hir_id(node_id);
@@ -4736,8 +4740,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    // Resolve associated value path into a base type and associated constant or method definition.
-    // The newly resolved definition is written into `type_dependent_defs`.
+    /// Resolves associated value path into a base type and associated constant or method
+    /// definition. The newly resolved definition is written into `type_dependent_defs`.
     pub fn resolve_ty_and_def_ufcs<'b>(&self,
                                        qpath: &'b QPath,
                                        node_id: ast::NodeId,
@@ -4840,15 +4844,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn check_stmt(&self, stmt: &'gcx hir::Stmt) {
         // Don't do all the complex logic below for `DeclItem`.
         match stmt.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                if let hir::DeclKind::Item(_) = decl.node {
-                    return
-                }
-            }
-            hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => {}
+            hir::StmtKind::Item(..) => return,
+            hir::StmtKind::Local(..) | hir::StmtKind::Expr(..) | hir::StmtKind::Semi(..) => {}
         }
 
-        self.warn_if_unreachable(stmt.node.id(), stmt.span, "statement");
+        self.warn_if_unreachable(stmt.id, stmt.span, "statement");
 
         // Hide the outer diverging and `has_errors` flags.
         let old_diverges = self.diverges.get();
@@ -4857,20 +4857,16 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         self.has_errors.set(false);
 
         match stmt.node {
-            hir::StmtKind::Decl(ref decl, _) => {
-                match decl.node {
-                    hir::DeclKind::Local(ref l) => {
-                        self.check_decl_local(&l);
-                    }
-                    // Ignore for now.
-                    hir::DeclKind::Item(_) => ()
-                }
+            hir::StmtKind::Local(ref l) => {
+                self.check_decl_local(&l);
             }
-            hir::StmtKind::Expr(ref expr, _) => {
+            // Ignore for now.
+            hir::StmtKind::Item(_) => {}
+            hir::StmtKind::Expr(ref expr) => {
                 // Check with expected type of `()`.
                 self.check_expr_has_type_or_error(&expr, self.tcx.mk_unit());
             }
-            hir::StmtKind::Semi(ref expr, _) => {
+            hir::StmtKind::Semi(ref expr) => {
                 self.check_expr(&expr);
             }
         }
@@ -5034,7 +5030,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         None
     }
 
-    /// Given a function block's `NodeId`, return its `FnDecl` if it exists, or `None` otherwise.
+    /// Given a function block's `NodeId`, returns its `FnDecl` if it exists, or `None` otherwise.
     fn get_parent_fn_decl(&self, blk_id: ast::NodeId) -> Option<(hir::FnDecl, ast::Ident)> {
         let parent = self.tcx.hir().get(self.tcx.hir().get_parent(blk_id));
         self.get_node_fn_decl(parent).map(|(fn_decl, ident, _)| (fn_decl, ident))
@@ -5076,11 +5072,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         })
     }
 
-    /// On implicit return expressions with mismatched types, provide the following suggestions:
+    /// On implicit return expressions with mismatched types, provides the following suggestions:
     ///
-    ///  - Point out the method's return type as the reason for the expected type
-    ///  - Possible missing semicolon
-    ///  - Possible missing return type if the return type is the default, and not `fn main()`
+    /// - Points out the method's return type as the reason for the expected type.
+    /// - Possible missing semicolon.
+    /// - Possible missing return type if the return type is the default, and not `fn main()`.
     pub fn suggest_mismatched_types_on_tail(
         &self,
         err: &mut DiagnosticBuilder<'tcx>,
@@ -5089,12 +5085,15 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         found: Ty<'tcx>,
         cause_span: Span,
         blk_id: ast::NodeId,
-    ) {
+    ) -> bool {
         self.suggest_missing_semicolon(err, expression, expected, cause_span);
+        let mut pointing_at_return_type = false;
         if let Some((fn_decl, can_suggest)) = self.get_fn_decl(blk_id) {
-            self.suggest_missing_return_type(err, &fn_decl, expected, found, can_suggest);
+            pointing_at_return_type = self.suggest_missing_return_type(
+                err, &fn_decl, expected, found, can_suggest);
         }
         self.suggest_ref_or_into(err, expression, expected, found);
+        pointing_at_return_type
     }
 
     pub fn suggest_ref_or_into(
@@ -5105,7 +5104,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         found: Ty<'tcx>,
     ) {
         if let Some((sp, msg, suggestion)) = self.check_ref(expr, found, expected) {
-            err.span_suggestion_with_applicability(
+            err.span_suggestion(
                 sp,
                 msg,
                 suggestion,
@@ -5132,7 +5131,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                         }
                     }).peekable();
                 if suggestions.peek().is_some() {
-                    err.span_suggestions_with_applicability(
+                    err.span_suggestions(
                         expr.span,
                         "try using a conversion method",
                         suggestions,
@@ -5143,7 +5142,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// A common error is to forget to add a semicolon at the end of a block:
+    /// A common error is to forget to add a semicolon at the end of a block, e.g.,
     ///
     /// ```
     /// fn foo() {
@@ -5171,7 +5170,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 ExprKind::Match(..) |
                 ExprKind::Block(..) => {
                     let sp = self.tcx.sess.source_map().next_point(cause_span);
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         sp,
                         "try adding a semicolon",
                         ";".to_string(),
@@ -5193,31 +5192,36 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     /// This routine checks if the return type is left as default, the method is not part of an
     /// `impl` block and that it isn't the `main` method. If so, it suggests setting the return
     /// type.
-    fn suggest_missing_return_type(&self,
-                                   err: &mut DiagnosticBuilder<'tcx>,
-                                   fn_decl: &hir::FnDecl,
-                                   expected: Ty<'tcx>,
-                                   found: Ty<'tcx>,
-                                   can_suggest: bool) {
+    fn suggest_missing_return_type(
+        &self,
+        err: &mut DiagnosticBuilder<'tcx>,
+        fn_decl: &hir::FnDecl,
+        expected: Ty<'tcx>,
+        found: Ty<'tcx>,
+        can_suggest: bool,
+    ) -> bool {
         // Only suggest changing the return type for methods that
         // haven't set a return type at all (and aren't `fn main()` or an impl).
         match (&fn_decl.output, found.is_suggestable(), can_suggest, expected.is_unit()) {
             (&hir::FunctionRetTy::DefaultReturn(span), true, true, true) => {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     span,
                     "try adding a return type",
                     format!("-> {} ", self.resolve_type_vars_with_obligations(found)),
                     Applicability::MachineApplicable);
+                true
             }
             (&hir::FunctionRetTy::DefaultReturn(span), false, true, true) => {
                 err.span_label(span, "possibly return type missing here?");
+                true
             }
             (&hir::FunctionRetTy::DefaultReturn(span), _, false, true) => {
                 // `fn main()` must return `()`, do not suggest changing return type
                 err.span_label(span, "expected `()` because of default return type");
+                true
             }
             // expectation was caused by something else, not the default return
-            (&hir::FunctionRetTy::DefaultReturn(_), _, _, false) => {}
+            (&hir::FunctionRetTy::DefaultReturn(_), _, _, false) => false,
             (&hir::FunctionRetTy::Return(ref ty), _, _, _) => {
                 // Only point to return type if the expected type is the return type, as if they
                 // are not, the expectation must have been caused by something else.
@@ -5229,7 +5233,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                 if ty.sty == expected.sty {
                     err.span_label(sp, format!("expected `{}` because of return type",
                                                expected));
+                    return true;
                 }
+                false
             }
         }
     }
@@ -5249,10 +5255,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         &self,
         blk: &'gcx hir::Block,
         expected_ty: Ty<'tcx>,
-        err: &mut DiagnosticBuilder,
+        err: &mut DiagnosticBuilder<'_>,
     ) {
         if let Some(span_semi) = self.could_remove_semicolon(blk, expected_ty) {
-            err.span_suggestion_with_applicability(
+            err.span_suggestion(
                 span_semi,
                 "consider removing this semicolon",
                 String::new(),
@@ -5273,7 +5279,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             None => return None,
         };
         let last_expr = match last_stmt.node {
-            hir::StmtKind::Semi(ref e, _) => e,
+            hir::StmtKind::Semi(ref e) => e,
             _ => return None,
         };
         let last_expr_ty = self.node_ty(last_expr.hir_id);
@@ -5428,7 +5434,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                 },
                                 AdtKind::Struct |
                                 AdtKind::Union => {
-                                    err.span_suggestion_with_applicability(
+                                    err.span_suggestion(
                                         span,
                                         "use curly brackets",
                                         String::from("Self { /* fields */ }"),
@@ -5642,7 +5648,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             query_result)
     }
 
-    /// Returns whether an expression is contained inside the LHS of an assignment expression.
+    /// Returns `true` if an expression is contained inside the LHS of an assignment expression.
     fn expr_in_place(&self, mut expr_id: ast::NodeId) -> bool {
         let mut contained_in_place = false;
 
@@ -5695,8 +5701,8 @@ pub fn check_bounds_are_used<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     });
     for (&used, param) in types_used.iter().zip(types) {
         if !used {
-            let id = tcx.hir().as_local_node_id(param.def_id).unwrap();
-            let span = tcx.hir().span(id);
+            let id = tcx.hir().as_local_hir_id(param.def_id).unwrap();
+            let span = tcx.hir().span_by_hir_id(id);
             struct_span_err!(tcx.sess, span, E0091, "type parameter `{}` is unused", param.name)
                 .span_label(span, "unused type parameter")
                 .emit();
@@ -5717,7 +5723,7 @@ fn fatally_break_rust(sess: &Session) {
     );
     handler.note_without_error(&format!("rustc {} running on {}",
         option_env!("CFG_VERSION").unwrap_or("unknown_version"),
-        ::session::config::host_triple(),
+        crate::session::config::host_triple(),
     ));
 }
 
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index 7c871601af308..9b1a656b1bc98 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -12,7 +12,7 @@ use syntax::ast::Ident;
 use rustc::hir;
 
 impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
-    /// Check a `a <op>= b`
+    /// Checks a `a <op>= b`
     pub fn check_binop_assign(&self,
                               expr: &'gcx hir::Expr,
                               op: hir::BinOp,
@@ -42,7 +42,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         ty
     }
 
-    /// Check a potentially overloaded binary operator.
+    /// Checks a potentially overloaded binary operator.
     pub fn check_binop(&self,
                        expr: &'gcx hir::Expr,
                        op: hir::BinOp,
@@ -280,7 +280,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                                             rty,
                                             lstring,
                                         );
-                                        err.span_suggestion_with_applicability(
+                                        err.span_suggestion(
                                             lhs_expr.span,
                                             msg,
                                             format!("*{}", lstring),
@@ -434,7 +434,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     err.span_label(expr.span,
                                    "`+` can't be used to concatenate two `&str` strings");
                     match source_map.span_to_snippet(lhs_expr.span) {
-                        Ok(lstring) => err.span_suggestion_with_applicability(
+                        Ok(lstring) => err.span_suggestion(
                             lhs_expr.span,
                             msg,
                             format!("{}.to_owned()", lstring),
@@ -455,7 +455,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
                     is_assign,
                 ) {
                     (Ok(l), Ok(r), false) => {
-                        err.multipart_suggestion_with_applicability(
+                        err.multipart_suggestion(
                             msg,
                             vec![
                                 (lhs_expr.span, format!("{}.to_owned()", l)),
@@ -672,7 +672,7 @@ enum Op {
     Unary(hir::UnOp, Span),
 }
 
-/// Returns true if this is a built-in arithmetic operation (e.g., u32
+/// Returns `true` if this is a built-in arithmetic operation (e.g., u32
 /// + u32, i16x4 == i16x4) and false if these types would have to be
 /// overloaded to be legal. There are two reasons that we distinguish
 /// builtin operations from overloaded ones (vs trying to drive
@@ -681,7 +681,7 @@ enum Op {
 ///
 /// 1. Builtin operations can trivially be evaluated in constants.
 /// 2. For comparison operators applied to SIMD types the result is
-///    not of type `bool`. For example, `i16x4==i16x4` yields a
+///    not of type `bool`. For example, `i16x4 == i16x4` yields a
 ///    type like `i16x4`. This means that the overloaded trait
 ///    `PartialEq` is not applicable.
 ///
diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs
index b90c18eb41cb5..792f8eaacd290 100644
--- a/src/librustc_typeck/check/regionck.rs
+++ b/src/librustc_typeck/check/regionck.rs
@@ -1,6 +1,6 @@
 //! The region check is a final pass that runs over the AST after we have
 //! inferred the type constraints but before we have actually finalized
-//! the types.  Its purpose is to embed a variety of region constraints.
+//! the types. Its purpose is to embed a variety of region constraints.
 //! Inserting these constraints as a separate pass is good because (1) it
 //! localizes the code that has to do with region inference and (2) often
 //! we cannot know what constraints are needed until the basic types have
@@ -34,17 +34,17 @@
 //! #### Reborrows
 //!
 //! Generally speaking, `regionck` does NOT try to ensure that the data
-//! `data` will outlive the pointer `x`. That is the job of borrowck.  The
+//! `data` will outlive the pointer `x`. That is the job of borrowck. The
 //! one exception is when "re-borrowing" the contents of another borrowed
 //! pointer. For example, imagine you have a borrowed pointer `b` with
-//! lifetime L1 and you have an expression `&*b`. The result of this
-//! expression will be another borrowed pointer with lifetime L2 (which is
+//! lifetime `L1` and you have an expression `&*b`. The result of this
+//! expression will be another borrowed pointer with lifetime `L2` (which is
 //! an inference variable). The borrow checker is going to enforce the
-//! constraint that L2 < L1, because otherwise you are re-borrowing data
-//! for a lifetime larger than the original loan.  However, without the
+//! constraint that `L2 < L1`, because otherwise you are re-borrowing data
+//! for a lifetime larger than the original loan. However, without the
 //! routines in this module, the region inferencer would not know of this
-//! dependency and thus it might infer the lifetime of L2 to be greater
-//! than L1 (issue #3148).
+//! dependency and thus it might infer the lifetime of `L2` to be greater
+//! than `L1` (issue #3148).
 //!
 //! There are a number of troublesome scenarios in the tests
 //! `region-dependent-*.rs`, but here is one example:
@@ -62,21 +62,21 @@
 //!
 //! The key point here is that when you are borrowing a value that
 //! is "guaranteed" by a borrowed pointer, you must link the
-//! lifetime of that borrowed pointer (L1, here) to the lifetime of
-//! the borrow itself (L2).  What do I mean by "guaranteed" by a
+//! lifetime of that borrowed pointer (`L1`, here) to the lifetime of
+//! the borrow itself (`L2`). What do I mean by "guaranteed" by a
 //! borrowed pointer? I mean any data that is reached by first
 //! dereferencing a borrowed pointer and then either traversing
-//! interior offsets or boxes.  We say that the guarantor
+//! interior offsets or boxes. We say that the guarantor
 //! of such data is the region of the borrowed pointer that was
-//! traversed.  This is essentially the same as the ownership
+//! traversed. This is essentially the same as the ownership
 //! relation, except that a borrowed pointer never owns its
 //! contents.
 
-use check::dropck;
-use check::FnCtxt;
-use middle::mem_categorization as mc;
-use middle::mem_categorization::Categorization;
-use middle::region;
+use crate::check::dropck;
+use crate::check::FnCtxt;
+use crate::middle::mem_categorization as mc;
+use crate::middle::mem_categorization::Categorization;
+use crate::middle::region;
 use rustc::hir::def_id::DefId;
 use rustc::infer::outlives::env::OutlivesEnvironment;
 use rustc::infer::{self, RegionObligation, SuppressRegionErrors};
@@ -112,7 +112,7 @@ macro_rules! ignore_err {
 impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn regionck_expr(&self, body: &'gcx hir::Body) {
         let subject = self.tcx.hir().body_owner_def_id(body.id());
-        let id = body.value.id;
+        let id = body.value.hir_id;
         let mut rcx = RegionCtxt::new(
             self,
             RepeatingScope(id),
@@ -138,9 +138,9 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
 
     /// Region checking during the WF phase for items. `wf_tys` are the
     /// types from which we should derive implied bounds, if any.
-    pub fn regionck_item(&self, item_id: ast::NodeId, span: Span, wf_tys: &[Ty<'tcx>]) {
+    pub fn regionck_item(&self, item_id: hir::HirId, span: Span, wf_tys: &[Ty<'tcx>]) {
         debug!("regionck_item(item.id={:?}, wf_tys={:?})", item_id, wf_tys);
-        let subject = self.tcx.hir().local_def_id(item_id);
+        let subject = self.tcx.hir().local_def_id_from_hir_id(item_id);
         let mut rcx = RegionCtxt::new(
             self,
             RepeatingScope(item_id),
@@ -166,18 +166,19 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
     pub fn regionck_fn(&self, fn_id: ast::NodeId, body: &'gcx hir::Body) {
         debug!("regionck_fn(id={})", fn_id);
         let subject = self.tcx.hir().body_owner_def_id(body.id());
-        let node_id = body.value.id;
+        let hir_id = body.value.hir_id;
         let mut rcx = RegionCtxt::new(
             self,
-            RepeatingScope(node_id),
-            node_id,
+            RepeatingScope(hir_id),
+            hir_id,
             Subject(subject),
             self.param_env,
         );
 
         if self.err_count_since_creation() == 0 {
+            let fn_hir_id = self.tcx.hir().node_to_hir_id(fn_id);
             // regionck assumes typeck succeeded
-            rcx.visit_fn_body(fn_id, body, self.tcx.hir().span(fn_id));
+            rcx.visit_fn_body(fn_hir_id, body, self.tcx.hir().span_by_hir_id(fn_hir_id));
         }
 
         rcx.resolve_regions_and_report_errors(SuppressRegionErrors::when_nll_is_enabled(self.tcx));
@@ -201,13 +202,13 @@ pub struct RegionCtxt<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     outlives_environment: OutlivesEnvironment<'tcx>,
 
     // id of innermost fn body id
-    body_id: ast::NodeId,
+    body_id: hir::HirId,
 
     // call_site scope of innermost fn
     call_site_scope: Option<region::Scope>,
 
     // id of innermost fn or loop
-    repeating_scope: ast::NodeId,
+    repeating_scope: hir::HirId,
 
     // id of AST node being analyzed (the subject of the analysis).
     subject_def_id: DefId,
@@ -220,14 +221,14 @@ impl<'a, 'gcx, 'tcx> Deref for RegionCtxt<'a, 'gcx, 'tcx> {
     }
 }
 
-pub struct RepeatingScope(ast::NodeId);
+pub struct RepeatingScope(hir::HirId);
 pub struct Subject(DefId);
 
 impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
     pub fn new(
         fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
         RepeatingScope(initial_repeating_scope): RepeatingScope,
-        initial_body_id: ast::NodeId,
+        initial_body_id: hir::HirId,
         Subject(subject): Subject,
         param_env: ty::ParamEnv<'tcx>,
     ) -> RegionCtxt<'a, 'gcx, 'tcx> {
@@ -244,15 +245,15 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    fn set_repeating_scope(&mut self, scope: ast::NodeId) -> ast::NodeId {
+    fn set_repeating_scope(&mut self, scope: hir::HirId) -> hir::HirId {
         mem::replace(&mut self.repeating_scope, scope)
     }
 
-    /// Try to resolve the type for the given node, returning t_err if an error results.  Note that
+    /// Try to resolve the type for the given node, returning `t_err` if an error results. Note that
     /// we never care about the details of the error, the same error will be detected and reported
     /// in the writeback phase.
     ///
-    /// Note one important point: we do not attempt to resolve *region variables* here.  This is
+    /// Note one important point: we do not attempt to resolve *region variables* here. This is
     /// because regionck is essentially adding constraints to those region variables and so may yet
     /// influence how they are resolved.
     ///
@@ -266,9 +267,9 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
     /// }
     /// ```
     ///
-    /// Here, the region of `b` will be `<R0>`.  `<R0>` is constrained to be some subregion of the
-    /// block B and some superregion of the call.  If we forced it now, we'd choose the smaller
-    /// region (the call).  But that would make the *b illegal.  Since we don't resolve, the type
+    /// Here, the region of `b` will be `<R0>`. `<R0>` is constrained to be some subregion of the
+    /// block B and some superregion of the call. If we forced it now, we'd choose the smaller
+    /// region (the call). But that would make the *b illegal. Since we don't resolve, the type
     /// of b will be `&<R0>.i32` and then `*b` will require that `<R0>` be bigger than the let and
     /// the `*b` expression, so we will effectively resolve `<R0>` to be the block B.
     pub fn resolve_type(&self, unresolved_ty: Ty<'tcx>) -> Ty<'tcx> {
@@ -301,15 +302,15 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
     /// `intravisit::Visitor` impl below.)
     fn visit_fn_body(
         &mut self,
-        id: ast::NodeId, // the id of the fn itself
+        id: hir::HirId, // the id of the fn itself
         body: &'gcx hir::Body,
         span: Span,
     ) {
         // When we enter a function, we can derive
-        debug!("visit_fn_body(id={})", id);
+        debug!("visit_fn_body(id={:?})", id);
 
         let body_id = body.id();
-        self.body_id = body_id.node_id;
+        self.body_id = body_id.hir_id;
 
         let call_site = region::Scope {
             id: body.value.hir_id.local_id,
@@ -318,11 +319,10 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         self.call_site_scope = Some(call_site);
 
         let fn_sig = {
-            let fn_hir_id = self.tcx.hir().node_to_hir_id(id);
-            match self.tables.borrow().liberated_fn_sigs().get(fn_hir_id) {
+            match self.tables.borrow().liberated_fn_sigs().get(id) {
                 Some(f) => f.clone(),
                 None => {
-                    bug!("No fn-sig entry for id={}", id);
+                    bug!("No fn-sig entry for id={:?}", id);
                 }
             }
         };
@@ -342,11 +342,11 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         self.outlives_environment.add_implied_bounds(
             self.fcx,
             &fn_sig_tys[..],
-            body_id.node_id,
+            body_id.hir_id,
             span,
         );
         self.outlives_environment
-            .save_implied_bounds(body_id.node_id);
+            .save_implied_bounds(body_id.hir_id);
         self.link_fn_args(
             region::Scope {
                 id: body.value.hir_id.local_id,
@@ -355,7 +355,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
             &body.arguments,
         );
         self.visit_body(body);
-        self.visit_region_obligations(body_id.node_id);
+        self.visit_region_obligations(body_id.hir_id);
 
         let call_site_scope = self.call_site_scope.unwrap();
         debug!(
@@ -365,8 +365,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         );
         let call_site_region = self.tcx.mk_region(ty::ReScope(call_site_scope));
 
-        let body_hir_id = self.tcx.hir().node_to_hir_id(body_id.node_id);
-        self.type_of_node_must_outlive(infer::CallReturn(span), body_hir_id, call_site_region);
+        self.type_of_node_must_outlive(infer::CallReturn(span), body_id.hir_id, call_site_region);
 
         self.constrain_opaque_types(
             &self.fcx.opaque_types.borrow(),
@@ -374,8 +373,8 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         );
     }
 
-    fn visit_region_obligations(&mut self, node_id: ast::NodeId) {
-        debug!("visit_region_obligations: node_id={}", node_id);
+    fn visit_region_obligations(&mut self, hir_id: hir::HirId) {
+        debug!("visit_region_obligations: hir_id={:?}", hir_id);
 
         // region checking can introduce new pending obligations
         // which, when processed, might generate new region
@@ -474,7 +473,8 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
         let env_snapshot = self.outlives_environment.push_snapshot_pre_closure();
 
         let body = self.tcx.hir().body(body_id);
-        self.visit_fn_body(id, body, span);
+        let hir_id = self.tcx.hir().node_to_hir_id(id);
+        self.visit_fn_body(hir_id, body, span);
 
         // Restore state from previous function.
         self.outlives_environment
@@ -502,7 +502,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
 
     fn visit_expr(&mut self, expr: &'gcx hir::Expr) {
         debug!(
-            "regionck::visit_expr(e={:?}, repeating_scope={})",
+            "regionck::visit_expr(e={:?}, repeating_scope={:?})",
             expr, self.repeating_scope
         );
 
@@ -555,7 +555,7 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
         }
 
         debug!(
-            "regionck::visit_expr(e={:?}, repeating_scope={}) - visiting subexprs",
+            "regionck::visit_expr(e={:?}, repeating_scope={:?}) - visiting subexprs",
             expr, self.repeating_scope
         );
         match expr.node {
@@ -679,16 +679,16 @@ impl<'a, 'gcx, 'tcx> Visitor<'gcx> for RegionCtxt<'a, 'gcx, 'tcx> {
             }
 
             hir::ExprKind::Loop(ref body, _, _) => {
-                let repeating_scope = self.set_repeating_scope(body.id);
+                let repeating_scope = self.set_repeating_scope(body.hir_id);
                 intravisit::walk_expr(self, expr);
                 self.set_repeating_scope(repeating_scope);
             }
 
             hir::ExprKind::While(ref cond, ref body, _) => {
-                let repeating_scope = self.set_repeating_scope(cond.id);
+                let repeating_scope = self.set_repeating_scope(cond.hir_id);
                 self.visit_expr(&cond);
 
-                self.set_repeating_scope(body.id);
+                self.set_repeating_scope(body.hir_id);
                 self.visit_block(&body);
 
                 self.set_repeating_scope(repeating_scope);
@@ -758,7 +758,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
     }
 
     fn check_expr_fn_block(&mut self, expr: &'gcx hir::Expr, body_id: hir::BodyId) {
-        let repeating_scope = self.set_repeating_scope(body_id.node_id);
+        let repeating_scope = self.set_repeating_scope(body_id.hir_id);
         intravisit::walk_expr(self, expr);
         self.set_repeating_scope(repeating_scope);
     }
@@ -826,7 +826,7 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
         }
     }
 
-    /// Create a temporary `MemCategorizationContext` and pass it to the closure.
+    /// Creates a temporary `MemCategorizationContext` and pass it to the closure.
     fn with_mc<F, R>(&self, f: F) -> R
     where
         F: for<'b> FnOnce(mc::MemCategorizationContext<'b, 'gcx, 'tcx>) -> R,
diff --git a/src/librustc_typeck/check/upvar.rs b/src/librustc_typeck/check/upvar.rs
index ffd7c2114e5ab..1816b7454dd2d 100644
--- a/src/librustc_typeck/check/upvar.rs
+++ b/src/librustc_typeck/check/upvar.rs
@@ -32,9 +32,9 @@
 
 use super::FnCtxt;
 
-use middle::expr_use_visitor as euv;
-use middle::mem_categorization as mc;
-use middle::mem_categorization::Categorization;
+use crate::middle::expr_use_visitor as euv;
+use crate::middle::mem_categorization as mc;
+use crate::middle::mem_categorization::Categorization;
 use rustc::hir;
 use rustc::hir::def_id::DefId;
 use rustc::hir::def_id::LocalDefId;
@@ -650,6 +650,5 @@ impl<'a, 'gcx, 'tcx> euv::Delegate<'tcx> for InferBorrowKind<'a, 'gcx, 'tcx> {
 }
 
 fn var_name(tcx: TyCtxt, var_hir_id: hir::HirId) -> ast::Name {
-    let var_node_id = tcx.hir().hir_to_node_id(var_hir_id);
-    tcx.hir().name(var_node_id)
+    tcx.hir().name_by_hir_id(var_hir_id)
 }
diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 53e44d53e6a9b..86b2e0bfe8aef 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -1,7 +1,7 @@
-use check::{Inherited, FnCtxt};
-use constrained_type_params::{identify_constrained_type_params, Parameter};
+use crate::check::{Inherited, FnCtxt};
+use crate::constrained_type_params::{identify_constrained_type_params, Parameter};
 
-use hir::def_id::DefId;
+use crate::hir::def_id::DefId;
 use rustc::traits::{self, ObligationCauseCode};
 use rustc::ty::{self, Lift, Ty, TyCtxt, TyKind, GenericParamDefKind, TypeFoldable, ToPredicate};
 use rustc::ty::subst::{Subst, Substs};
@@ -14,7 +14,7 @@ use syntax::feature_gate::{self, GateIssue};
 use syntax_pos::Span;
 use errors::{DiagnosticBuilder, DiagnosticId};
 
-use rustc::hir::intravisit::{self, Visitor, NestedVisitorMap};
+use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::hir;
 
 /// Helper type of a temporary returned by `.for_item(...)`.
@@ -22,7 +22,7 @@ use rustc::hir;
 /// `F: for<'b, 'tcx> where 'gcx: 'tcx FnOnce(FnCtxt<'b, 'gcx, 'tcx>)`.
 struct CheckWfFcxBuilder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     inherited: super::InheritedBuilder<'a, 'gcx, 'tcx>,
-    id: ast::NodeId,
+    id: hir::HirId,
     span: Span,
     param_env: ty::ParamEnv<'tcx>,
 }
@@ -62,11 +62,11 @@ impl<'a, 'gcx, 'tcx> CheckWfFcxBuilder<'a, 'gcx, 'tcx> {
 /// not included it frequently leads to confusing errors in fn bodies. So it's better to check
 /// the types first.
 pub fn check_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) {
-    let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
-    let item = tcx.hir().expect_item(node_id);
+    let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
+    let item = tcx.hir().expect_item_by_hir_id(hir_id);
 
-    debug!("check_item_well_formed(it.id={}, it.name={})",
-           item.id,
+    debug!("check_item_well_formed(it.hir_id={:?}, it.name={})",
+           item.hir_id,
            tcx.item_path_str(def_id));
 
     match item.node {
@@ -88,7 +88,7 @@ pub fn check_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: Def
         // won't be allowed unless there's an *explicit* implementation of `Send`
         // for `T`
         hir::ItemKind::Impl(_, polarity, defaultness, _, ref trait_ref, ref self_ty, _) => {
-            let is_auto = tcx.impl_trait_ref(tcx.hir().local_def_id(item.id))
+            let is_auto = tcx.impl_trait_ref(tcx.hir().local_def_id_from_hir_id(item.hir_id))
                                 .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.def_id));
             if let (hir::Defaultness::Default { .. }, true) = (defaultness, is_auto) {
                 tcx.sess.span_err(item.span, "impls of auto traits cannot be default");
@@ -226,9 +226,10 @@ fn for_item<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, item: &hir::Item)
 fn for_id<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>, id: ast::NodeId, span: Span)
                           -> CheckWfFcxBuilder<'a, 'gcx, 'tcx> {
     let def_id = tcx.hir().local_def_id(id);
+    let hir_id = tcx.hir().node_to_hir_id(id);
     CheckWfFcxBuilder {
         inherited: Inherited::build(tcx, def_id),
-        id,
+        id: hir_id,
         span,
         param_env: tcx.param_env(def_id),
     }
@@ -408,7 +409,7 @@ fn check_impl<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     });
 }
 
-/// Checks where clauses and inline bounds that are declared on def_id.
+/// Checks where-clauses and inline bounds that are declared on `def_id`.
 fn check_where_clauses<'a, 'gcx, 'fcx, 'tcx>(
     tcx: TyCtxt<'a, 'gcx, 'gcx>,
     fcx: &FnCtxt<'fcx, 'gcx, 'tcx>,
@@ -608,8 +609,8 @@ fn check_existential_types<'a, 'fcx, 'gcx, 'tcx>(
             if let ty::Opaque(def_id, substs) = ty.sty {
                 trace!("check_existential_types: opaque_ty, {:?}, {:?}", def_id, substs);
                 let generics = tcx.generics_of(def_id);
-                // only check named existential types
-                if generics.parent.is_none() {
+                // only check named existential types defined in this crate
+                if generics.parent.is_none() && def_id.is_local() {
                     let opaque_node_id = tcx.hir().as_local_node_id(def_id).unwrap();
                     if may_define_existential_type(tcx, fn_def_id, opaque_node_id) {
                         trace!("check_existential_types may define. Generics: {:#?}", generics);
@@ -790,7 +791,7 @@ fn check_method_receiver<'fcx, 'gcx, 'tcx>(fcx: &FnCtxt<'fcx, 'gcx, 'tcx>,
 /// through a `*const/mut T` raw pointer. If the feature is not enabled, the requirements are more
 /// strict: `receiver_ty` must implement `Receiver` and directly implement `Deref<Target=self_ty>`.
 ///
-/// NB: there are cases this function returns `true` but causes an error to be emitted,
+/// N.B., there are cases this function returns `true` but causes an error to be emitted,
 /// particularly when `receiver_ty` derefs to a type that is the same as `self_ty` but has the
 /// wrong lifetime. Be careful of this if you are calling this function speculatively.
 fn receiver_is_valid<'fcx, 'tcx, 'gcx>(
@@ -963,18 +964,18 @@ fn reject_shadowing_parameters(tcx: TyCtxt, def_id: DefId) {
     }
 }
 
-/// Feature gates RFC 2056 - trivial bounds, checking for global bounds that
+/// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that
 /// aren't true.
 fn check_false_global_bounds<'a, 'gcx, 'tcx>(
     fcx: &FnCtxt<'a, 'gcx, 'tcx>,
     span: Span,
-    id: ast::NodeId)
+    id: hir::HirId)
 {
     use rustc::ty::TypeFoldable;
 
     let empty_env = ty::ParamEnv::empty();
 
-    let def_id = fcx.tcx.hir().local_def_id(id);
+    let def_id = fcx.tcx.hir().local_def_id_from_hir_id(id);
     let predicates = fcx.tcx.predicates_of(def_id).predicates
         .iter()
         .map(|(p, _)| *p)
@@ -1015,30 +1016,23 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
     }
 }
 
-impl<'a, 'tcx, 'v> Visitor<'v> for CheckTypeWellFormedVisitor<'a, 'tcx> {
-    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'v> {
-        NestedVisitorMap::None
-    }
-
-    fn visit_item(&mut self, i: &hir::Item) {
+impl<'a, 'tcx> ItemLikeVisitor<'tcx> for CheckTypeWellFormedVisitor<'a, 'tcx> {
+    fn visit_item(&mut self, i: &'tcx hir::Item) {
         debug!("visit_item: {:?}", i);
         let def_id = self.tcx.hir().local_def_id(i.id);
-        ty::query::queries::check_item_well_formed::ensure(self.tcx, def_id);
-        intravisit::walk_item(self, i);
+        self.tcx.ensure().check_item_well_formed(def_id);
     }
 
-    fn visit_trait_item(&mut self, trait_item: &'v hir::TraitItem) {
+    fn visit_trait_item(&mut self, trait_item: &'tcx hir::TraitItem) {
         debug!("visit_trait_item: {:?}", trait_item);
         let def_id = self.tcx.hir().local_def_id(trait_item.id);
-        ty::query::queries::check_trait_item_well_formed::ensure(self.tcx, def_id);
-        intravisit::walk_trait_item(self, trait_item)
+        self.tcx.ensure().check_trait_item_well_formed(def_id);
     }
 
-    fn visit_impl_item(&mut self, impl_item: &'v hir::ImplItem) {
+    fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
         debug!("visit_impl_item: {:?}", impl_item);
         let def_id = self.tcx.hir().local_def_id(impl_item.id);
-        ty::query::queries::check_impl_item_well_formed::ensure(self.tcx, def_id);
-        intravisit::walk_impl_item(self, impl_item)
+        self.tcx.ensure().check_impl_item_well_formed(def_id);
     }
 }
 
diff --git a/src/librustc_typeck/check/writeback.rs b/src/librustc_typeck/check/writeback.rs
index c61159eb49481..e4c0e3bd54d5d 100644
--- a/src/librustc_typeck/check/writeback.rs
+++ b/src/librustc_typeck/check/writeback.rs
@@ -2,7 +2,7 @@
 // unresolved type variables and replaces "ty_var" types with their
 // substitutions.
 
-use check::FnCtxt;
+use crate::check::FnCtxt;
 use errors::DiagnosticBuilder;
 use rustc::hir;
 use rustc::hir::def_id::{DefId, DefIndex};
@@ -100,7 +100,7 @@ impl<'cx, 'gcx, 'tcx> WritebackCx<'cx, 'gcx, 'tcx> {
         body: &'gcx hir::Body,
         rustc_dump_user_substs: bool,
     ) -> WritebackCx<'cx, 'gcx, 'tcx> {
-        let owner = fcx.tcx.hir().definitions().node_to_hir_id(body.id().node_id);
+        let owner = body.id().hir_id;
 
         WritebackCx {
             fcx,
@@ -404,11 +404,10 @@ impl<'cx, 'gcx, 'tcx> WritebackCx<'cx, 'gcx, 'tcx> {
                 .user_provided_types_mut()
                 .insert(hir_id, c_ty.clone());
 
-            if let ty::UserTypeAnnotation::TypeOf(_, user_substs) = c_ty.value {
+            if let ty::UserType::TypeOf(_, user_substs) = c_ty.value {
                 if self.rustc_dump_user_substs {
                     // This is a unit-testing mechanism.
-                    let node_id = self.tcx().hir().hir_to_node_id(hir_id);
-                    let span = self.tcx().hir().span(node_id);
+                    let span = self.tcx().hir().span_by_hir_id(hir_id);
                     // We need to buffer the errors in order to guarantee a consistent
                     // order when emitting them.
                     let err = self.tcx().sess.struct_span_err(
@@ -561,21 +560,29 @@ impl<'cx, 'gcx, 'tcx> WritebackCx<'cx, 'gcx, 'tcx> {
                 if def_id == defin_ty_def_id {
                     // Concrete type resolved to the existential type itself
                     // Force a cycle error
+                    // FIXME(oli-obk): we could just not insert it into `concrete_existential_types`
+                    // which simply would make this use not a defining use.
                     self.tcx().at(span).type_of(defin_ty_def_id);
                 }
             }
 
+            let new = ty::ResolvedOpaqueTy {
+                concrete_type: definition_ty,
+                substs: self.tcx().lift_to_global(&opaque_defn.substs).unwrap(),
+            };
+
             let old = self.tables
                 .concrete_existential_types
-                .insert(def_id, definition_ty);
+                .insert(def_id, new);
             if let Some(old) = old {
-                if old != definition_ty {
+                if old.concrete_type != definition_ty || old.substs != opaque_defn.substs {
                     span_bug!(
                         span,
                         "visit_opaque_types tried to write \
-                        different types for the same existential type: {:?}, {:?}, {:?}",
+                        different types for the same existential type: {:?}, {:?}, {:?}, {:?}",
                         def_id,
                         definition_ty,
+                        opaque_defn,
                         old,
                     );
                 }
@@ -739,15 +746,14 @@ impl Locatable for ast::NodeId {
 
 impl Locatable for DefIndex {
     fn to_span(&self, tcx: &TyCtxt) -> Span {
-        let node_id = tcx.hir().def_index_to_node_id(*self);
-        tcx.hir().span(node_id)
+        let hir_id = tcx.hir().def_index_to_hir_id(*self);
+        tcx.hir().span_by_hir_id(hir_id)
     }
 }
 
 impl Locatable for hir::HirId {
     fn to_span(&self, tcx: &TyCtxt) -> Span {
-        let node_id = tcx.hir().hir_to_node_id(*self);
-        tcx.hir().span(node_id)
+        tcx.hir().span_by_hir_id(*self)
     }
 }
 
diff --git a/src/librustc_typeck/check_unused.rs b/src/librustc_typeck/check_unused.rs
index bf767726ef715..70f7c30f7ecb6 100644
--- a/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@ -1,4 +1,4 @@
-use lint;
+use crate::lint;
 use rustc::ty::TyCtxt;
 
 use errors::Applicability;
@@ -136,7 +136,7 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
                     .fold(span, |acc, attr_span| acc.to(attr_span));
 
                 tcx.struct_span_lint_node(lint, id, span, msg)
-                    .span_suggestion_short_with_applicability(
+                    .span_suggestion_short(
                         span_with_attrs,
                         "remove it",
                         String::new(),
@@ -178,7 +178,7 @@ fn unused_crates_lint<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>) {
         };
         let replacement = visibility_qualified(&item.vis, base_replacement);
         tcx.struct_span_lint_node(lint, id, extern_crate.span, msg)
-            .span_suggestion_short_with_applicability(
+            .span_suggestion_short(
                 extern_crate.span,
                 &help,
                 replacement,
@@ -194,7 +194,7 @@ struct CollectExternCrateVisitor<'a, 'tcx: 'a> {
 }
 
 struct ExternCrateToLint {
-    /// def-id of the extern crate
+    /// `DefId` of the extern crate
     def_id: DefId,
 
     /// span from the item
diff --git a/src/librustc_typeck/coherence/builtin.rs b/src/librustc_typeck/coherence/builtin.rs
index bd2373d1659c9..0996d1ff3b998 100644
--- a/src/librustc_typeck/coherence/builtin.rs
+++ b/src/librustc_typeck/coherence/builtin.rs
@@ -76,7 +76,7 @@ fn visit_implementation_of_drop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_did:
 fn visit_implementation_of_copy<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_did: DefId) {
     debug!("visit_implementation_of_copy: impl_did={:?}", impl_did);
 
-    let impl_node_id = if let Some(n) = tcx.hir().as_local_node_id(impl_did) {
+    let impl_hir_id = if let Some(n) = tcx.hir().as_local_hir_id(impl_did) {
         n
     } else {
         debug!("visit_implementation_of_copy(): impl not in this crate");
@@ -87,7 +87,7 @@ fn visit_implementation_of_copy<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_did:
     debug!("visit_implementation_of_copy: self_type={:?} (bound)",
            self_type);
 
-    let span = tcx.hir().span(impl_node_id);
+    let span = tcx.hir().span_by_hir_id(impl_hir_id);
     let param_env = tcx.param_env(impl_did);
     assert!(!self_type.has_escaping_bound_vars());
 
@@ -97,7 +97,7 @@ fn visit_implementation_of_copy<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_did:
     match param_env.can_type_implement_copy(tcx, self_type) {
         Ok(()) => {}
         Err(CopyImplementationError::InfrigingFields(fields)) => {
-            let item = tcx.hir().expect_item(impl_node_id);
+            let item = tcx.hir().expect_item_by_hir_id(impl_hir_id);
             let span = if let ItemKind::Impl(.., Some(ref tr), _, _) = item.node {
                 tr.path.span
             } else {
@@ -114,7 +114,7 @@ fn visit_implementation_of_copy<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, impl_did:
             err.emit()
         }
         Err(CopyImplementationError::NotAnAdt) => {
-            let item = tcx.hir().expect_item(impl_node_id);
+            let item = tcx.hir().expect_item_by_hir_id(impl_hir_id);
             let span = if let ItemKind::Impl(.., ref ty, _) = item.node {
                 ty.span
             } else {
@@ -162,8 +162,8 @@ fn visit_implementation_of_dispatch_from_dyn<'a, 'tcx>(
     if impl_did.is_local() {
         let dispatch_from_dyn_trait = tcx.lang_items().dispatch_from_dyn_trait().unwrap();
 
-        let impl_node_id = tcx.hir().as_local_node_id(impl_did).unwrap();
-        let span = tcx.hir().span(impl_node_id);
+        let impl_hir_id = tcx.hir().as_local_hir_id(impl_did).unwrap();
+        let span = tcx.hir().span_by_hir_id(impl_hir_id);
 
         let source = tcx.type_of(impl_did);
         assert!(!source.has_escaping_bound_vars());
@@ -185,7 +185,7 @@ fn visit_implementation_of_dispatch_from_dyn<'a, 'tcx>(
         };
 
         tcx.infer_ctxt().enter(|infcx| {
-            let cause = ObligationCause::misc(span, impl_node_id);
+            let cause = ObligationCause::misc(span, impl_hir_id);
 
             use ty::TyKind::*;
             match (&source.sty, &target.sty) {
@@ -332,7 +332,7 @@ pub fn coerce_unsized_info<'a, 'gcx>(gcx: TyCtxt<'a, 'gcx, 'gcx>,
     });
 
     // this provider should only get invoked for local def-ids
-    let impl_node_id = gcx.hir().as_local_node_id(impl_did).unwrap_or_else(|| {
+    let impl_hir_id = gcx.hir().as_local_hir_id(impl_did).unwrap_or_else(|| {
         bug!("coerce_unsized_info: invoked for non-local def-id {:?}", impl_did)
     });
 
@@ -344,7 +344,7 @@ pub fn coerce_unsized_info<'a, 'gcx>(gcx: TyCtxt<'a, 'gcx, 'gcx>,
            source,
            target);
 
-    let span = gcx.hir().span(impl_node_id);
+    let span = gcx.hir().span_by_hir_id(impl_hir_id);
     let param_env = gcx.param_env(impl_did);
     assert!(!source.has_escaping_bound_vars());
 
@@ -355,7 +355,7 @@ pub fn coerce_unsized_info<'a, 'gcx>(gcx: TyCtxt<'a, 'gcx, 'gcx>,
            target);
 
     gcx.infer_ctxt().enter(|infcx| {
-        let cause = ObligationCause::misc(span, impl_node_id);
+        let cause = ObligationCause::misc(span, impl_hir_id);
         let check_mutbl = |mt_a: ty::TypeAndMut<'gcx>,
                            mt_b: ty::TypeAndMut<'gcx>,
                            mk_ptr: &dyn Fn(Ty<'gcx>) -> Ty<'gcx>| {
@@ -481,11 +481,11 @@ pub fn coerce_unsized_info<'a, 'gcx>(gcx: TyCtxt<'a, 'gcx, 'gcx>,
                                being coerced, none found");
                     return err_info;
                 } else if diff_fields.len() > 1 {
-                    let item = gcx.hir().expect_item(impl_node_id);
+                    let item = gcx.hir().expect_item_by_hir_id(impl_hir_id);
                     let span = if let ItemKind::Impl(.., Some(ref t), _, _) = item.node {
                         t.path.span
                     } else {
-                        gcx.hir().span(impl_node_id)
+                        gcx.hir().span_by_hir_id(impl_hir_id)
                     };
 
                     let mut err = struct_span_err!(gcx.sess,
@@ -527,7 +527,7 @@ pub fn coerce_unsized_info<'a, 'gcx>(gcx: TyCtxt<'a, 'gcx, 'gcx>,
         let mut fulfill_cx = TraitEngine::new(infcx.tcx);
 
         // Register an obligation for `A: Trait<B>`.
-        let cause = traits::ObligationCause::misc(span, impl_node_id);
+        let cause = traits::ObligationCause::misc(span, impl_hir_id);
         let predicate = gcx.predicate_for_trait_def(param_env,
                                                     cause,
                                                     trait_def_id,
diff --git a/src/librustc_typeck/coherence/inherent_impls_overlap.rs b/src/librustc_typeck/coherence/inherent_impls_overlap.rs
index 52dee29294cb7..138c598a7bbf0 100644
--- a/src/librustc_typeck/coherence/inherent_impls_overlap.rs
+++ b/src/librustc_typeck/coherence/inherent_impls_overlap.rs
@@ -1,11 +1,11 @@
-use namespace::Namespace;
+use crate::namespace::Namespace;
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
 use rustc::hir;
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::traits::{self, IntercrateMode};
 use rustc::ty::TyCtxt;
 
-use lint;
+use crate::lint;
 
 pub fn crate_inherent_impls_overlap_check<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                                                     crate_num: CrateNum) {
diff --git a/src/librustc_typeck/coherence/mod.rs b/src/librustc_typeck/coherence/mod.rs
index 8053ed130e91b..24e5ca989c4b2 100644
--- a/src/librustc_typeck/coherence/mod.rs
+++ b/src/librustc_typeck/coherence/mod.rs
@@ -5,10 +5,11 @@
 // done by the orphan and overlap modules. Then we build up various
 // mappings. That mapping code resides here.
 
-use hir::def_id::{DefId, LOCAL_CRATE};
+use crate::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::traits;
 use rustc::ty::{self, TyCtxt, TypeFoldable};
 use rustc::ty::query::Providers;
+use rustc::util::common::time;
 
 use syntax::ast;
 
@@ -132,23 +133,25 @@ fn coherent_trait<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) {
     for &impl_id in impls {
         check_impl_overlap(tcx, impl_id);
     }
-    builtin::check_trait(tcx, def_id);
+    use rustc::util::common::time;
+    time(tcx.sess, "builtin::check_trait checking", ||
+          builtin::check_trait(tcx, def_id));
 }
 
 pub fn check_coherence<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &trait_def_id in tcx.hir().krate().trait_impls.keys() {
-        ty::query::queries::coherent_trait::ensure(tcx, trait_def_id);
+        tcx.ensure().coherent_trait(trait_def_id);
     }
 
-    unsafety::check(tcx);
-    orphan::check(tcx);
+    time(tcx.sess, "unsafety checking", || unsafety::check(tcx));
+    time(tcx.sess, "orphan checking", || orphan::check(tcx));
 
     // these queries are executed for side-effects (error reporting):
-    ty::query::queries::crate_inherent_impls::ensure(tcx, LOCAL_CRATE);
-    ty::query::queries::crate_inherent_impls_overlap_check::ensure(tcx, LOCAL_CRATE);
+    tcx.ensure().crate_inherent_impls(LOCAL_CRATE);
+    tcx.ensure().crate_inherent_impls_overlap_check(LOCAL_CRATE);
 }
 
-/// Overlap: No two impls for the same trait are implemented for the
+/// Overlap: no two impls for the same trait are implemented for the
 /// same type. Likewise, no two inherent impls for a given type
 /// constructor provide a method with the same name.
 fn check_impl_overlap<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, node_id: ast::NodeId) {
diff --git a/src/librustc_typeck/coherence/orphan.rs b/src/librustc_typeck/coherence/orphan.rs
index 2df137c3f5094..b776a980b7c97 100644
--- a/src/librustc_typeck/coherence/orphan.rs
+++ b/src/librustc_typeck/coherence/orphan.rs
@@ -17,7 +17,7 @@ struct OrphanChecker<'cx, 'tcx: 'cx> {
 
 impl<'cx, 'tcx, 'v> ItemLikeVisitor<'v> for OrphanChecker<'cx, 'tcx> {
     /// Checks exactly one impl for orphan rules and other such
-    /// restrictions.  In this fn, it can happen that multiple errors
+    /// restrictions. In this fn, it can happen that multiple errors
     /// apply to a specific impl, so just return after reporting one
     /// to prevent inundating the user with a bunch of similar error
     /// reports.
diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index 3a546f84469e6..ec1d9d24730ed 100644
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -14,19 +14,19 @@
 //! At present, however, we do run collection across all items in the
 //! crate as a kind of pass. This should eventually be factored away.
 
-use astconv::{AstConv, Bounds};
-use constrained_type_params as ctp;
-use check::intrinsic::intrisic_operation_unsafety;
-use lint;
-use middle::lang_items::SizedTraitLangItem;
-use middle::resolve_lifetime as rl;
-use middle::weak_lang_items;
+use crate::astconv::{AstConv, Bounds};
+use crate::constrained_type_params as ctp;
+use crate::check::intrinsic::intrisic_operation_unsafety;
+use crate::lint;
+use crate::middle::lang_items::SizedTraitLangItem;
+use crate::middle::resolve_lifetime as rl;
+use crate::middle::weak_lang_items;
 use rustc::mir::mono::Linkage;
 use rustc::ty::query::Providers;
-use rustc::ty::query::queries;
-use rustc::ty::subst::Substs;
+use rustc::ty::subst::{Subst, Substs};
 use rustc::ty::util::Discr;
 use rustc::ty::util::IntTypeExt;
+use rustc::ty::subst::UnpackedKind;
 use rustc::ty::{self, AdtKind, ToPolyTraitRef, Ty, TyCtxt};
 use rustc::ty::{ReprOptions, ToPredicate};
 use rustc::util::captures::Captures;
@@ -36,7 +36,7 @@ use rustc_target::spec::abi;
 
 use syntax::ast;
 use syntax::ast::{Ident, MetaItemKind};
-use syntax::attr::{InlineAttr, list_contains_name, mark_used};
+use syntax::attr::{InlineAttr, OptimizeAttr, list_contains_name, mark_used};
 use syntax::source_map::Spanned;
 use syntax::feature_gate;
 use syntax::symbol::{keywords, Symbol};
@@ -58,7 +58,7 @@ struct OnlySelfBounds(bool);
 
 pub fn collect_item_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     for &module in tcx.hir().krate().modules.keys() {
-        queries::collect_mod_item_types::ensure(tcx, tcx.hir().local_def_id(module));
+        tcx.ensure().collect_mod_item_types(tcx.hir().local_def_id(module));
     }
 }
 
@@ -69,7 +69,7 @@ fn collect_mod_item_types<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefI
     );
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         type_of,
         generics_of,
@@ -93,7 +93,7 @@ pub fn provide(providers: &mut Providers) {
 ///////////////////////////////////////////////////////////////////////////
 
 /// Context specific to some particular item. This is what implements
-/// AstConv. It has information about the predicates that are defined
+/// `AstConv`. It has information about the predicates that are defined
 /// on the trait. Unfortunately, this predicate information is
 /// available in various different forms at various points in the
 /// process. So we can't just store a pointer to e.g., the AST or the
@@ -133,6 +133,10 @@ impl<'a, 'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'a, 'tcx> {
                     self.tcx.type_of(def_id);
                 }
                 hir::GenericParamKind::Type { .. } => {}
+                hir::GenericParamKind::Const { .. } => {
+                    let def_id = self.tcx.hir().local_def_id(param.id);
+                    self.tcx.type_of(def_id);
+                }
             }
         }
         intravisit::walk_generics(self, generics);
@@ -326,7 +330,7 @@ fn type_param_predicates<'a, 'tcx>(
 }
 
 impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
-    /// Find bounds from `hir::Generics`. This requires scanning through the
+    /// Finds bounds from `hir::Generics`. This requires scanning through the
     /// AST. We do this to avoid having to convert *all* the bounds, which
     /// would create artificial cycles. Instead we can only convert the
     /// bounds for a type parameter `X` if `X::Foo` is used.
@@ -372,7 +376,7 @@ impl<'a, 'tcx> ItemCtxt<'a, 'tcx> {
 }
 
 /// Tests whether this is the AST for a reference to the type
-/// parameter with id `param_id`. We use this so as to avoid running
+/// parameter with ID `param_id`. We use this so as to avoid running
 /// `ast_ty_to_ty`, because we want to avoid triggering an all-out
 /// conversion of the type to avoid inducing unnecessary cycles.
 fn is_param<'a, 'tcx>(
@@ -681,7 +685,7 @@ fn adt_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty::Ad
     tcx.alloc_adt_def(def_id, kind, variants, repr)
 }
 
-/// Ensures that the super-predicates of the trait with def-id
+/// Ensures that the super-predicates of the trait with `DefId`
 /// trait_def_id are converted and stored. This also ensures that
 /// the transitive super-predicates are converted;
 fn super_predicates_of<'a, 'tcx>(
@@ -715,7 +719,7 @@ fn super_predicates_of<'a, 'tcx>(
     // In the case of trait aliases, however, we include all bounds in the where clause,
     // so e.g., `trait Foo = where u32: PartialEq<Self>` would include `u32: PartialEq<Self>`
     // as one of its "superpredicates".
-    let is_trait_alias = ty::is_trait_alias(tcx, trait_def_id);
+    let is_trait_alias = tcx.is_trait_alias(trait_def_id);
     let superbounds2 = icx.type_parameter_bounds_in_generics(
         generics, item.id, self_param_ty, OnlySelfBounds(!is_trait_alias));
 
@@ -738,8 +742,8 @@ fn super_predicates_of<'a, 'tcx>(
 }
 
 fn trait_def<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty::TraitDef {
-    let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
-    let item = tcx.hir().expect_item(node_id);
+    let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
+    let item = tcx.hir().expect_item_by_hir_id(hir_id);
 
     let (is_auto, unsafety) = match item.node {
         hir::ItemKind::Trait(is_auto, unsafety, ..) => (is_auto == hir::IsAuto::Yes, unsafety),
@@ -815,8 +819,7 @@ fn has_late_bound_regions<'a, 'tcx>(
                 return;
             }
 
-            let hir_id = self.tcx.hir().node_to_hir_id(lt.id);
-            match self.tcx.named_region(hir_id) {
+            match self.tcx.named_region(lt.hir_id) {
                 Some(rl::Region::Static) | Some(rl::Region::EarlyBound(..)) => {}
                 Some(rl::Region::LateBound(debruijn, _, _))
                 | Some(rl::Region::LateBoundAnon(debruijn, _)) if debruijn < self.outer_index => {}
@@ -842,8 +845,7 @@ fn has_late_bound_regions<'a, 'tcx>(
         };
         for param in &generics.params {
             if let GenericParamKind::Lifetime { .. } = param.kind {
-                let hir_id = tcx.hir().node_to_hir_id(param.id);
-                if tcx.is_late_bound(hir_id) {
+                if tcx.is_late_bound(param.hir_id) {
                     return Some(param.span);
                 }
             }
@@ -1044,6 +1046,22 @@ fn generics_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> &'tcx ty
                     i += 1;
                     Some(ty_param)
                 }
+                GenericParamKind::Const { .. } => {
+                    if param.name.ident().name == keywords::SelfUpper.name() {
+                        span_bug!(
+                            param.span,
+                            "`Self` should not be the name of a regular parameter",
+                        );
+                    }
+
+                    // Emit an error, but skip the parameter rather than aborting to
+                    // continue to get other errors.
+                    tcx.sess.struct_span_err(
+                        param.span,
+                        "const generics in any position are currently unsupported",
+                    ).emit();
+                    None
+                }
                 _ => None,
             }),
     );
@@ -1194,7 +1212,7 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Ty<'tcx> {
                     tcx.typeck_tables_of(owner)
                         .concrete_existential_types
                         .get(&def_id)
-                        .cloned()
+                        .map(|opaque| opaque.concrete_type)
                         .unwrap_or_else(|| {
                             // This can occur if some error in the
                             // owner fn prevented us from populating
@@ -1256,7 +1274,7 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Ty<'tcx> {
         }) => {
             if gen.is_some() {
                 let hir_id = tcx.hir().node_to_hir_id(node_id);
-                return tcx.typeck_tables_of(def_id).node_id_to_type(hir_id);
+                return tcx.typeck_tables_of(def_id).node_type(hir_id);
             }
 
             let substs = ty::ClosureSubsts {
@@ -1303,12 +1321,12 @@ fn type_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Ty<'tcx> {
             }
         },
 
-        Node::GenericParam(param) => match param.kind {
-            hir::GenericParamKind::Type {
-                default: Some(ref ty),
-                ..
-            } => icx.to_ty(ty),
-            _ => bug!("unexpected non-type NodeGenericParam"),
+        Node::GenericParam(param) => match &param.kind {
+            hir::GenericParamKind::Type { default: Some(ref ty), .. } |
+            hir::GenericParamKind::Const { ref ty, .. } => {
+                icx.to_ty(ty)
+            }
+            x => bug!("unexpected non-type Node::GenericParam: {:?}", x),
         },
 
         x => {
@@ -1326,7 +1344,13 @@ fn find_existential_constraints<'a, 'tcx>(
     struct ConstraintLocator<'a, 'tcx: 'a> {
         tcx: TyCtxt<'a, 'tcx, 'tcx>,
         def_id: DefId,
-        found: Option<(Span, ty::Ty<'tcx>)>,
+        // First found type span, actual type, mapping from the existential type's generic
+        // parameters to the concrete type's generic parameters
+        //
+        // The mapping is an index for each use site of a generic parameter in the concrete type
+        //
+        // The indices index into the generic parameters on the existential type.
+        found: Option<(Span, ty::Ty<'tcx>, Vec<usize>)>,
     }
 
     impl<'a, 'tcx> ConstraintLocator<'a, 'tcx> {
@@ -1341,23 +1365,106 @@ fn find_existential_constraints<'a, 'tcx>(
                 .tcx
                 .typeck_tables_of(def_id)
                 .concrete_existential_types
-                .get(&self.def_id)
-                .cloned();
-            if let Some(ty) = ty {
+                .get(&self.def_id);
+            if let Some(ty::ResolvedOpaqueTy { concrete_type, substs }) = ty {
                 // FIXME(oli-obk): trace the actual span from inference to improve errors
                 let span = self.tcx.def_span(def_id);
-                if let Some((prev_span, prev_ty)) = self.found {
-                    if ty != prev_ty {
+                // used to quickly look up the position of a generic parameter
+                let mut index_map: FxHashMap<ty::ParamTy, usize> = FxHashMap::default();
+                // skip binder is ok, since we only use this to find generic parameters and their
+                // positions.
+                for (idx, subst) in substs.iter().enumerate() {
+                    if let UnpackedKind::Type(ty) = subst.unpack() {
+                        if let ty::Param(p) = ty.sty {
+                            if index_map.insert(p, idx).is_some() {
+                                // there was already an entry for `p`, meaning a generic parameter
+                                // was used twice
+                                self.tcx.sess.span_err(
+                                    span,
+                                    &format!("defining existential type use restricts existential \
+                                    type by using the generic parameter `{}` twice", p.name),
+                                );
+                                return;
+                            }
+                        } else {
+                            self.tcx.sess.delay_span_bug(
+                                span,
+                                &format!(
+                                    "non-defining exist ty use in defining scope: {:?}, {:?}",
+                                    concrete_type, substs,
+                                ),
+                            );
+                        }
+                    }
+                }
+                // compute the index within the existential type for each generic parameter used in
+                // the concrete type
+                let indices = concrete_type
+                    .subst(self.tcx, substs)
+                    .walk()
+                    .filter_map(|t| match &t.sty {
+                        ty::Param(p) => Some(*index_map.get(p).unwrap()),
+                        _ => None,
+                    }).collect();
+                let is_param = |ty: ty::Ty| match ty.sty {
+                    ty::Param(_) => true,
+                    _ => false,
+                };
+                if !substs.types().all(is_param) {
+                    self.tcx.sess.span_err(
+                        span,
+                        "defining existential type use does not fully define existential type",
+                    );
+                } else if let Some((prev_span, prev_ty, ref prev_indices)) = self.found {
+                    let mut ty = concrete_type.walk().fuse();
+                    let mut p_ty = prev_ty.walk().fuse();
+                    let iter_eq = (&mut ty).zip(&mut p_ty).all(|(t, p)| match (&t.sty, &p.sty) {
+                        // type parameters are equal to any other type parameter for the purpose of
+                        // concrete type equality, as it is possible to obtain the same type just
+                        // by passing matching parameters to a function.
+                        (ty::Param(_), ty::Param(_)) => true,
+                        _ => t == p,
+                    });
+                    if !iter_eq || ty.next().is_some() || p_ty.next().is_some() {
                         // found different concrete types for the existential type
                         let mut err = self.tcx.sess.struct_span_err(
                             span,
-                            "defining existential type use differs from previous",
+                            "concrete type differs from previous defining existential type use",
+                        );
+                        err.span_label(
+                            span,
+                            format!("expected `{}`, got `{}`", prev_ty, concrete_type),
+                        );
+                        err.span_note(prev_span, "previous use here");
+                        err.emit();
+                    } else if indices != *prev_indices {
+                        // found "same" concrete types, but the generic parameter order differs
+                        let mut err = self.tcx.sess.struct_span_err(
+                            span,
+                            "concrete type's generic parameters differ from previous defining use",
                         );
+                        use std::fmt::Write;
+                        let mut s = String::new();
+                        write!(s, "expected [").unwrap();
+                        let list = |s: &mut String, indices: &Vec<usize>| {
+                            let mut indices = indices.iter().cloned();
+                            if let Some(first) = indices.next() {
+                                write!(s, "`{}`", substs[first]).unwrap();
+                                for i in indices {
+                                    write!(s, ", `{}`", substs[i]).unwrap();
+                                }
+                            }
+                        };
+                        list(&mut s, prev_indices);
+                        write!(s, "], got [").unwrap();
+                        list(&mut s, &indices);
+                        write!(s, "]").unwrap();
+                        err.span_label(span, s);
                         err.span_note(prev_span, "previous use here");
                         err.emit();
                     }
                 } else {
-                    self.found = Some((span, ty));
+                    self.found = Some((span, concrete_type, indices));
                 }
             }
         }
@@ -1416,7 +1523,7 @@ fn find_existential_constraints<'a, 'tcx>(
     }
 
     match locator.found {
-        Some((_, ty)) => ty,
+        Some((_, ty, _)) => ty,
         None => {
             let span = tcx.def_span(def_id);
             tcx.sess.span_err(span, "could not find defining uses");
@@ -1456,11 +1563,11 @@ fn fn_sig<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> ty::PolyFnSig
             compute_sig_of_foreign_fn_decl(tcx, def_id, fn_decl, abi)
         }
 
-        StructCtor(&VariantData::Tuple(ref fields, _))
+        StructCtor(&VariantData::Tuple(ref fields, ..))
         | Variant(&Spanned {
             node:
                 hir::VariantKind {
-                    data: VariantData::Tuple(ref fields, _),
+                    data: VariantData::Tuple(ref fields, ..),
                     ..
                 },
             ..
@@ -1512,8 +1619,8 @@ fn impl_trait_ref<'a, 'tcx>(
 ) -> Option<ty::TraitRef<'tcx>> {
     let icx = ItemCtxt::new(tcx, def_id);
 
-    let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
-    match tcx.hir().expect_item(node_id).node {
+    let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
+    match tcx.hir().expect_item_by_hir_id(hir_id).node {
         hir::ItemKind::Impl(.., ref opt_trait_ref, _, _) => {
             opt_trait_ref.as_ref().map(|ast_trait_ref| {
                 let selfty = tcx.type_of(def_id);
@@ -1525,8 +1632,8 @@ fn impl_trait_ref<'a, 'tcx>(
 }
 
 fn impl_polarity<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> hir::ImplPolarity {
-    let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
-    match tcx.hir().expect_item(node_id).node {
+    let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
+    match tcx.hir().expect_item_by_hir_id(hir_id).node {
         hir::ItemKind::Impl(_, polarity, ..) => polarity,
         ref item => bug!("impl_polarity: {:?} not an impl", item),
     }
@@ -1584,7 +1691,7 @@ fn is_unsized<'gcx: 'tcx, 'tcx>(
 }
 
 /// Returns the early-bound lifetimes declared in this generics
-/// listing.  For anything other than fns/methods, this is just all
+/// listing. For anything other than fns/methods, this is just all
 /// the lifetimes that are declared. For fns or methods, we have to
 /// screen out those that do not appear in any where-clauses etc using
 /// `resolve_lifetime::early_bound_lifetimes`.
@@ -1604,6 +1711,9 @@ fn early_bound_lifetimes_from_generics<'a, 'tcx>(
         })
 }
 
+/// Returns a list of type predicates for the definition with ID `def_id`, including inferred
+/// lifetime constraints. This includes all predicates returned by `explicit_predicates_of`, plus
+/// inferred constraints concerning which regions outlive other regions.
 fn predicates_defined_on<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     def_id: DefId,
@@ -1631,6 +1741,9 @@ fn predicates_defined_on<'a, 'tcx>(
     result
 }
 
+/// Returns a list of all type predicates (explicit and implicit) for the definition with
+/// ID `def_id`. This includes all predicates returned by `predicates_defined_on`, plus
+/// `Self: Trait` predicates for traits.
 fn predicates_of<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     def_id: DefId,
@@ -1659,6 +1772,8 @@ fn predicates_of<'a, 'tcx>(
     result
 }
 
+/// Returns a list of user-specified type predicates for the definition with ID `def_id`.
+/// N.B., this does not include any implied/inferred constraints.
 fn explicit_predicates_of<'a, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     def_id: DefId,
@@ -2054,9 +2169,9 @@ pub fn compute_bounds<'gcx: 'tcx, 'tcx>(
 }
 
 /// Converts a specific `GenericBound` from the AST into a set of
-/// predicates that apply to the self-type. A vector is returned
-/// because this can be anywhere from zero predicates (`T : ?Sized` adds no
-/// predicates) to one (`T : Foo`) to many (`T : Bar<X=i32>` adds `T : Bar`
+/// predicates that apply to the self type. A vector is returned
+/// because this can be anywhere from zero predicates (`T: ?Sized` adds no
+/// predicates) to one (`T: Foo`) to many (`T: Bar<X=i32>` adds `T: Bar`
 /// and `<T as Bar>::X == i32`).
 fn predicates_from_bound<'tcx>(
     astconv: &dyn AstConv<'tcx, 'tcx>,
@@ -2205,6 +2320,7 @@ fn from_target_feature(
                 Some("wasm_target_feature") => rust_features.wasm_target_feature,
                 Some("cmpxchg16b_target_feature") => rust_features.cmpxchg16b_target_feature,
                 Some("adx_target_feature") => rust_features.adx_target_feature,
+                Some("movbe_target_feature") => rust_features.movbe_target_feature,
                 Some(name) => bug!("unknown target feature gate {}", name),
                 None => true,
             };
@@ -2286,49 +2402,6 @@ fn codegen_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> Codegen
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::USED;
         } else if attr.check_name("thread_local") {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
-        } else if attr.check_name("inline") {
-            codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
-                if attr.path != "inline" {
-                    return ia;
-                }
-                let meta = match attr.meta() {
-                    Some(meta) => meta.node,
-                    None => return ia,
-                };
-                match meta {
-                    MetaItemKind::Word => {
-                        mark_used(attr);
-                        InlineAttr::Hint
-                    }
-                    MetaItemKind::List(ref items) => {
-                        mark_used(attr);
-                        inline_span = Some(attr.span);
-                        if items.len() != 1 {
-                            span_err!(
-                                tcx.sess.diagnostic(),
-                                attr.span,
-                                E0534,
-                                "expected one argument"
-                            );
-                            InlineAttr::None
-                        } else if list_contains_name(&items[..], "always") {
-                            InlineAttr::Always
-                        } else if list_contains_name(&items[..], "never") {
-                            InlineAttr::Never
-                        } else {
-                            span_err!(
-                                tcx.sess.diagnostic(),
-                                items[0].span,
-                                E0535,
-                                "invalid argument"
-                            );
-
-                            InlineAttr::None
-                        }
-                    }
-                    _ => ia,
-                }
-            });
         } else if attr.check_name("export_name") {
             if let Some(s) = attr.value_str() {
                 if s.as_str().contains("\0") {
@@ -2378,6 +2451,76 @@ fn codegen_fn_attrs<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, id: DefId) -> Codegen
         }
     }
 
+    codegen_fn_attrs.inline = attrs.iter().fold(InlineAttr::None, |ia, attr| {
+        if attr.path != "inline" {
+            return ia;
+        }
+        match attr.meta().map(|i| i.node) {
+            Some(MetaItemKind::Word) => {
+                mark_used(attr);
+                InlineAttr::Hint
+            }
+            Some(MetaItemKind::List(ref items)) => {
+                mark_used(attr);
+                inline_span = Some(attr.span);
+                if items.len() != 1 {
+                    span_err!(
+                        tcx.sess.diagnostic(),
+                        attr.span,
+                        E0534,
+                        "expected one argument"
+                    );
+                    InlineAttr::None
+                } else if list_contains_name(&items[..], "always") {
+                    InlineAttr::Always
+                } else if list_contains_name(&items[..], "never") {
+                    InlineAttr::Never
+                } else {
+                    span_err!(
+                        tcx.sess.diagnostic(),
+                        items[0].span,
+                        E0535,
+                        "invalid argument"
+                    );
+
+                    InlineAttr::None
+                }
+            }
+            Some(MetaItemKind::NameValue(_)) => ia,
+            None => ia,
+        }
+    });
+
+    codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
+        if attr.path != "optimize" {
+            return ia;
+        }
+        let err = |sp, s| span_err!(tcx.sess.diagnostic(), sp, E0722, "{}", s);
+        match attr.meta().map(|i| i.node) {
+            Some(MetaItemKind::Word) => {
+                err(attr.span, "expected one argument");
+                ia
+            }
+            Some(MetaItemKind::List(ref items)) => {
+                mark_used(attr);
+                inline_span = Some(attr.span);
+                if items.len() != 1 {
+                    err(attr.span, "expected one argument");
+                    OptimizeAttr::None
+                } else if list_contains_name(&items[..], "size") {
+                    OptimizeAttr::Size
+                } else if list_contains_name(&items[..], "speed") {
+                    OptimizeAttr::Speed
+                } else {
+                    err(items[0].span, "invalid argument");
+                    OptimizeAttr::None
+                }
+            }
+            Some(MetaItemKind::NameValue(_)) => ia,
+            None => ia,
+        }
+    });
+
     // If a function uses #[target_feature] it can't be inlined into general
     // purpose functions as they wouldn't have the right target features
     // enabled. For that reason we also forbid #[inline(always)] as it can't be
diff --git a/src/librustc_typeck/constrained_type_params.rs b/src/librustc_typeck/constrained_type_params.rs
index 199ea315896df..6a530f454d2b3 100644
--- a/src/librustc_typeck/constrained_type_params.rs
+++ b/src/librustc_typeck/constrained_type_params.rs
@@ -14,7 +14,7 @@ impl From<ty::EarlyBoundRegion> for Parameter {
     fn from(param: ty::EarlyBoundRegion) -> Self { Parameter(param.index) }
 }
 
-/// Return the set of parameters constrained by the impl header.
+/// Returns the set of parameters constrained by the impl header.
 pub fn parameters_for_impl<'tcx>(impl_self_ty: Ty<'tcx>,
                                  impl_trait_ref: Option<ty::TraitRef<'tcx>>)
                                  -> FxHashSet<Parameter>
@@ -89,7 +89,7 @@ pub fn identify_constrained_type_params<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>,
 /// parameters so constrained to `input_parameters`. For example,
 /// imagine the following impl:
 ///
-///     impl<T: Debug, U: Iterator<Item=T>> Trait for U
+///     impl<T: Debug, U: Iterator<Item = T>> Trait for U
 ///
 /// The impl's predicates are collected from left to right. Ignoring
 /// the implicit `Sized` bounds, these are
@@ -112,10 +112,10 @@ pub fn identify_constrained_type_params<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>,
 /// We *do* have to be somewhat careful when projection targets contain
 /// projections themselves, for example in
 ///     impl<S,U,V,W> Trait for U where
-/// /* 0 */   S: Iterator<Item=U>,
+/// /* 0 */   S: Iterator<Item = U>,
 /// /* - */   U: Iterator,
 /// /* 1 */   <U as Iterator>::Item: ToOwned<Owned=(W,<V as Iterator>::Item)>
-/// /* 2 */   W: Iterator<Item=V>
+/// /* 2 */   W: Iterator<Item = V>
 /// /* 3 */   V: Debug
 /// we have to evaluate the projections in the order I wrote them:
 /// `V: Debug` requires `V` to be evaluated. The only projection that
@@ -124,7 +124,7 @@ pub fn identify_constrained_type_params<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>,
 /// which is determined by 1, which requires `U`, that is determined
 /// by 0. I should probably pick a less tangled example, but I can't
 /// think of any.
-pub fn setup_constraining_predicates<'tcx>(tcx: TyCtxt,
+pub fn setup_constraining_predicates<'tcx>(tcx: TyCtxt<'_, '_, '_>,
                                            predicates: &mut [(ty::Predicate<'tcx>, Span)],
                                            impl_trait_ref: Option<ty::TraitRef<'tcx>>,
                                            input_parameters: &mut FxHashSet<Parameter>)
diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 4e3ea5ca9cf54..3c4a0760f3ee2 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -1,3 +1,4 @@
+// ignore-tidy-linelength
 #![allow(non_snake_case)]
 
 register_long_diagnostics! {
@@ -348,13 +349,14 @@ fn main() {
 "##,
 
 E0044: r##"
-You can't use type parameters on foreign items. Example of erroneous code:
+You can't use type or const parameters on foreign items.
+Example of erroneous code:
 
 ```compile_fail,E0044
 extern { fn some_func<T>(x: T); }
 ```
 
-To fix this, replace the type parameter with the specializations that you
+To fix this, replace the generic parameter with the specializations that you
 need:
 
 ```
@@ -516,7 +518,7 @@ recursion limit (which can be set via the `recursion_limit` attribute).
 For a somewhat artificial example:
 
 ```compile_fail,E0055
-#![recursion_limit="2"]
+#![recursion_limit="5"]
 
 struct Foo;
 
@@ -526,9 +528,9 @@ impl Foo {
 
 fn main() {
     let foo = Foo;
-    let ref_foo = &&Foo;
+    let ref_foo = &&&&&Foo;
 
-    // error, reached the recursion limit while auto-dereferencing `&&Foo`
+    // error, reached the recursion limit while auto-dereferencing `&&&&&Foo`
     ref_foo.foo();
 }
 ```
@@ -763,7 +765,7 @@ function's return type and the value being returned.
 "##,
 
 E0070: r##"
-The left-hand side of an assignment operator must be a place expression. An
+The left-hand side of an assignment operator must be a place expression. A
 place expression represents a memory location and can be a variable (with
 optional namespacing), a dereference, an indexing expression or a field
 reference.
@@ -1324,6 +1326,10 @@ type X = u32; // ok!
 ```
 "##,
 
+E0111: r##"
+You tried to give a const parameter to a type which doesn't need it.
+"##,
+
 E0116: r##"
 You can only define an inherent implementation for a type in the same crate
 where the type was defined. For example, an `impl` block as below is not allowed
@@ -1543,7 +1549,9 @@ fn f<T>() {}
 
 It is not possible to declare type parameters on a function that has the `start`
 attribute. Such a function must have the following type signature (for more
-information: http://doc.rust-lang.org/stable/book/first-edition/no-stdlib.html):
+information, view [the unstable book][1]):
+
+[1]: https://doc.rust-lang.org/unstable-book/language-features/lang-items.html#writing-an-executable-without-stdlib
 
 ```
 # let _:
@@ -2917,10 +2925,11 @@ impl Baz for Bar { } // Note: This is OK
 
 E0374: r##"
 A struct without a field containing an unsized type cannot implement
-`CoerceUnsized`. An
-[unsized type](https://doc.rust-lang.org/book/first-edition/unsized-types.html)
-is any type that the compiler doesn't know the length or alignment of at
-compile time. Any struct containing an unsized type is also unsized.
+`CoerceUnsized`. An [unsized type][1] is any type that the compiler
+doesn't know the length or alignment of at compile time. Any struct
+containing an unsized type is also unsized.
+
+[1]: https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait
 
 Example of erroneous code:
 
@@ -2977,9 +2986,9 @@ A struct with more than one field containing an unsized type cannot implement
 `CoerceUnsized`. This only occurs when you are trying to coerce one of the
 types in your struct to another type in the struct. In this case we try to
 impl `CoerceUnsized` from `T` to `U` which are both types that the struct
-takes. An [unsized type] is any type that the compiler doesn't know the length
-or alignment of at compile time. Any struct containing an unsized type is also
-unsized.
+takes. An [unsized type][1] is any type that the compiler doesn't know the
+length or alignment of at compile time. Any struct containing an unsized type
+is also unsized.
 
 Example of erroneous code:
 
@@ -3024,7 +3033,7 @@ fn coerce_foo<T: CoerceUnsized<U>, U>(t: T) -> Foo<U> {
 }
 ```
 
-[unsized type]: https://doc.rust-lang.org/book/first-edition/unsized-types.html
+[1]: https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait
 "##,
 
 E0376: r##"
@@ -3032,11 +3041,12 @@ The type you are trying to impl `CoerceUnsized` for is not a struct.
 `CoerceUnsized` can only be implemented for a struct. Unsized types are
 already able to be coerced without an implementation of `CoerceUnsized`
 whereas a struct containing an unsized type needs to know the unsized type
-field it's containing is able to be coerced. An
-[unsized type](https://doc.rust-lang.org/book/first-edition/unsized-types.html)
+field it's containing is able to be coerced. An [unsized type][1]
 is any type that the compiler doesn't know the length or alignment of at
 compile time. Any struct containing an unsized type is also unsized.
 
+[1]: https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait
+
 Example of erroneous code:
 
 ```compile_fail,E0376
@@ -3882,8 +3892,10 @@ let c = 86u8 as char; // ok!
 assert_eq!(c, 'V');
 ```
 
-For more information about casts, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/casting-between-types.html
+For more information about casts, take a look at the Type cast section in
+[The Reference Book][1].
+
+[1]: https://doc.rust-lang.org/reference/expressions/operator-expr.html#type-cast-expressions
 "##,
 
 E0605: r##"
@@ -3911,8 +3923,10 @@ let v = 0 as *const u8;
 v as *const i8; // ok!
 ```
 
-For more information about casts, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/casting-between-types.html
+For more information about casts, take a look at the Type cast section in
+[The Reference Book][1].
+
+[1]: https://doc.rust-lang.org/reference/expressions/operator-expr.html#type-cast-expressions
 "##,
 
 E0606: r##"
@@ -3933,8 +3947,10 @@ let x = &0u8;
 let y: u32 = *x as u32; // We dereference it first and then cast it.
 ```
 
-For more information about casts, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/casting-between-types.html
+For more information about casts, take a look at the Type cast section in
+[The Reference Book][1].
+
+[1]: https://doc.rust-lang.org/reference/expressions/operator-expr.html#type-cast-expressions
 "##,
 
 E0607: r##"
@@ -3960,8 +3976,10 @@ pointer holds is their size.
 
 To fix this error, don't try to cast directly between thin and fat pointers.
 
-For more information about casts, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/casting-between-types.html
+For more information about casts, take a look at the Type cast section in
+[The Reference Book][1].
+
+[1]: https://doc.rust-lang.org/reference/expressions/operator-expr.html#type-cast-expressions
 "##,
 
 E0609: r##"
@@ -4019,8 +4037,8 @@ println!("x: {}, y: {}", variable.x, variable.y);
 ```
 
 For more information about primitives and structs, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/primitive-types.html
-https://doc.rust-lang.org/book/first-edition/structs.html
+https://doc.rust-lang.org/book/ch03-02-data-types.html
+https://doc.rust-lang.org/book/ch05-00-structs.html
 "##,
 
 E0614: r##"
@@ -4719,4 +4737,5 @@ register_diagnostics! {
     E0645, // trait aliases not finished
     E0698, // type inside generator must be known in this context
     E0719, // duplicate values for associated type binding
+    E0722, // Malformed #[optimize] attribute
 }
diff --git a/src/librustc_typeck/impl_wf_check.rs b/src/librustc_typeck/impl_wf_check.rs
index d5e15b28fb04b..ed39874eeaada 100644
--- a/src/librustc_typeck/impl_wf_check.rs
+++ b/src/librustc_typeck/impl_wf_check.rs
@@ -8,25 +8,26 @@
 //! specialization errors. These things can (and probably should) be
 //! fixed, but for the moment it's easier to do these checks early.
 
-use constrained_type_params as ctp;
+use crate::constrained_type_params as ctp;
 use rustc::hir;
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::hir::def_id::DefId;
 use rustc::ty::{self, TyCtxt};
+use rustc::ty::query::Providers;
 use rustc::util::nodemap::{FxHashMap, FxHashSet};
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 
 use syntax_pos::Span;
 
 /// Checks that all the type/lifetime parameters on an impl also
-/// appear in the trait ref or self-type (or are constrained by a
+/// appear in the trait ref or self type (or are constrained by a
 /// where-clause). These rules are needed to ensure that, given a
 /// trait ref like `<T as Trait<U>>`, we can derive the values of all
 /// parameters on the impl (which is needed to make specialization
 /// possible).
 ///
 /// However, in the case of lifetimes, we only enforce these rules if
-/// the lifetime parameter is used in an associated type.  This is a
+/// the lifetime parameter is used in an associated type. This is a
 /// concession to backwards compatibility; see comment at the end of
 /// the fn for details.
 ///
@@ -39,7 +40,7 @@ use syntax_pos::Span;
 /// impl<T> Trait<Foo<T>> for Bar { ... }
 /// //   ^ T appears in `Foo<T>`, ok.
 ///
-/// impl<T> Trait<Foo> for Bar where Bar: Iterator<Item=T> { ... }
+/// impl<T> Trait<Foo> for Bar where Bar: Iterator<Item = T> { ... }
 /// //   ^ T is bound to `<Bar as Iterator>::Item`, ok.
 ///
 /// impl<'a> Trait<Foo> for Bar { }
@@ -52,7 +53,23 @@ pub fn impl_wf_check<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
     // We will tag this as part of the WF check -- logically, it is,
     // but it's one that we must perform earlier than the rest of
     // WfCheck.
-    tcx.hir().krate().visit_all_item_likes(&mut ImplWfCheck { tcx });
+    for &module in tcx.hir().krate().modules.keys() {
+        tcx.ensure().check_mod_impl_wf(tcx.hir().local_def_id(module));
+    }
+}
+
+fn check_mod_impl_wf<'tcx>(tcx: TyCtxt<'_, 'tcx, 'tcx>, module_def_id: DefId) {
+    tcx.hir().visit_item_likes_in_module(
+        module_def_id,
+        &mut ImplWfCheck { tcx }
+    );
+}
+
+pub fn provide(providers: &mut Providers<'_>) {
+    *providers = Providers {
+        check_mod_impl_wf,
+        ..*providers
+    };
 }
 
 struct ImplWfCheck<'a, 'tcx: 'a> {
@@ -145,7 +162,7 @@ fn enforce_impl_params_are_constrained<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     // used elsewhere are not projected back out.
 }
 
-fn report_unused_parameter(tcx: TyCtxt,
+fn report_unused_parameter(tcx: TyCtxt<'_, '_, '_>,
                            span: Span,
                            kind: &str,
                            name: &str)
diff --git a/src/librustc_typeck/lib.rs b/src/librustc_typeck/lib.rs
index 8bd484aa0d352..2dcb48692f6bd 100644
--- a/src/librustc_typeck/lib.rs
+++ b/src/librustc_typeck/lib.rs
@@ -1,6 +1,6 @@
 /*!
 
-# typeck.rs
+# typeck
 
 The type checker is responsible for:
 
@@ -55,9 +55,7 @@ This API is completely unstable and subject to change.
 
 */
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
 #![allow(non_camel_case_types)]
 
@@ -66,26 +64,22 @@ This API is completely unstable and subject to change.
 #![feature(crate_visibility_modifier)]
 #![feature(exhaustive_patterns)]
 #![feature(nll)]
-#![feature(quote)]
 #![feature(refcell_replace_swap)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(slice_patterns)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(never_type)]
 
 #![recursion_limit="256"]
 
+#![deny(rust_2018_idioms)]
+#![allow(explicit_outlives_requirements)]
+
+#![allow(elided_lifetimes_in_paths)] // WIP
+
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
-extern crate syntax_pos;
-
-extern crate arena;
 
 #[macro_use] extern crate rustc;
-extern crate rustc_data_structures;
-extern crate rustc_errors as errors;
-extern crate rustc_target;
-extern crate smallvec;
 
 // N.B., this module needs to be declared first so diagnostics are
 // registered before they are used.
@@ -103,23 +97,22 @@ mod namespace;
 mod outlives;
 mod variance;
 
-use hir::Node;
 use rustc_target::spec::abi::Abi;
-use rustc::hir;
+use rustc::hir::{self, Node};
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::infer::InferOk;
 use rustc::lint;
 use rustc::middle;
 use rustc::session;
-use rustc::session::config::nightly_options;
+use rustc::session::CompileIncomplete;
+use rustc::session::config::{EntryFnType, nightly_options};
 use rustc::traits::{ObligationCause, ObligationCauseCode, TraitEngine, TraitEngineExt};
 use rustc::ty::subst::Substs;
 use rustc::ty::{self, Ty, TyCtxt};
 use rustc::ty::query::Providers;
 use rustc::util;
 use rustc::util::profiling::ProfileCategory;
-use session::{CompileIncomplete, config};
 use syntax_pos::Span;
-use syntax::ast;
 use util::common::time;
 
 use std::iter;
@@ -145,7 +138,7 @@ fn check_type_alias_enum_variants_enabled<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx,
     }
 }
 
-fn require_c_abi_if_variadic(tcx: TyCtxt,
+fn require_c_abi_if_variadic(tcx: TyCtxt<'_, '_, '_>,
                              decl: &hir::FnDecl,
                              abi: Abi,
                              span: Span) {
@@ -184,14 +177,13 @@ fn require_same_types<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     })
 }
 
-fn check_main_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                              main_id: ast::NodeId,
-                              main_span: Span) {
-    let main_def_id = tcx.hir().local_def_id(main_id);
+fn check_main_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, main_def_id: DefId) {
+    let main_id = tcx.hir().as_local_hir_id(main_def_id).unwrap();
+    let main_span = tcx.def_span(main_def_id);
     let main_t = tcx.type_of(main_def_id);
     match main_t.sty {
         ty::FnDef(..) => {
-            if let Some(Node::Item(it)) = tcx.hir().find(main_id) {
+            if let Some(Node::Item(it)) = tcx.hir().find_by_hir_id(main_id) {
                 if let hir::ItemKind::Fn(.., ref generics, _) = it.node {
                     let mut error = false;
                     if !generics.params.is_empty() {
@@ -250,14 +242,13 @@ fn check_main_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     }
 }
 
-fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
-                               start_id: ast::NodeId,
-                               start_span: Span) {
-    let start_def_id = tcx.hir().local_def_id(start_id);
+fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, start_def_id: DefId) {
+    let start_id = tcx.hir().as_local_hir_id(start_def_id).unwrap();
+    let start_span = tcx.def_span(start_def_id);
     let start_t = tcx.type_of(start_def_id);
     match start_t.sty {
         ty::FnDef(..) => {
-            if let Some(Node::Item(it)) = tcx.hir().find(start_id) {
+            if let Some(Node::Item(it)) = tcx.hir().find_by_hir_id(start_id) {
                 if let hir::ItemKind::Fn(.., ref generics, _) = it.node {
                     let mut error = false;
                     if !generics.params.is_empty() {
@@ -309,20 +300,20 @@ fn check_start_fn_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 }
 
 fn check_for_entry_fn<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
-    if let Some((id, sp, entry_type)) = *tcx.sess.entry_fn.borrow() {
-        match entry_type {
-            config::EntryFnType::Main => check_main_fn_ty(tcx, id, sp),
-            config::EntryFnType::Start => check_start_fn_ty(tcx, id, sp),
-        }
+    match tcx.entry_fn(LOCAL_CRATE) {
+        Some((def_id, EntryFnType::Main)) => check_main_fn_ty(tcx, def_id),
+        Some((def_id, EntryFnType::Start)) => check_start_fn_ty(tcx, def_id),
+        _ => {}
     }
 }
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     collect::provide(providers);
     coherence::provide(providers);
     check::provide(providers);
     variance::provide(providers);
     outlives::provide(providers);
+    impl_wf_check::provide(providers);
 }
 
 pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>)
@@ -338,10 +329,12 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>)
 
     })?;
 
-    tcx.sess.track_errors(|| {
-        time(tcx.sess, "outlives testing", ||
-            outlives::test::test_inferred_outlives(tcx));
-    })?;
+    if tcx.features().rustc_attrs {
+        tcx.sess.track_errors(|| {
+            time(tcx.sess, "outlives testing", ||
+                outlives::test::test_inferred_outlives(tcx));
+        })?;
+    }
 
     tcx.sess.track_errors(|| {
         time(tcx.sess, "impl wf inference", ||
@@ -353,10 +346,12 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>)
           coherence::check_coherence(tcx));
     })?;
 
-    tcx.sess.track_errors(|| {
-        time(tcx.sess, "variance testing", ||
-             variance::test::test_variance(tcx));
-    })?;
+    if tcx.features().rustc_attrs {
+        tcx.sess.track_errors(|| {
+            time(tcx.sess, "variance testing", ||
+                variance::test::test_variance(tcx));
+        })?;
+    }
 
     time(tcx.sess, "wf checking", || check::check_wf_new(tcx))?;
 
diff --git a/src/librustc_typeck/outlives/explicit.rs b/src/librustc_typeck/outlives/explicit.rs
index 38f4b37b29289..574086f780a9d 100644
--- a/src/librustc_typeck/outlives/explicit.rs
+++ b/src/librustc_typeck/outlives/explicit.rs
@@ -1,6 +1,6 @@
 use rustc::hir::def_id::DefId;
 use rustc::ty::{self, OutlivesPredicate, TyCtxt};
-use util::nodemap::FxHashMap;
+use crate::util::nodemap::FxHashMap;
 
 use super::utils::*;
 
diff --git a/src/librustc_typeck/outlives/implicit_infer.rs b/src/librustc_typeck/outlives/implicit_infer.rs
index e388a3e0d0c2f..6c56e9991c8a8 100644
--- a/src/librustc_typeck/outlives/implicit_infer.rs
+++ b/src/librustc_typeck/outlives/implicit_infer.rs
@@ -1,5 +1,4 @@
-use rustc::hir;
-use hir::Node;
+use rustc::hir::{self, Node};
 use rustc::hir::def_id::DefId;
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
 use rustc::ty::subst::{Kind, Subst, UnpackedKind};
@@ -12,7 +11,7 @@ use super::utils::*;
 
 /// Infer predicates for the items in the crate.
 ///
-/// global_inferred_outlives: this is initially the empty map that
+/// `global_inferred_outlives`: this is initially the empty map that
 ///     was generated by walking the items in the crate. This will
 ///     now be filled with inferred predicates.
 pub fn infer_predicates<'tcx>(
diff --git a/src/librustc_typeck/outlives/mod.rs b/src/librustc_typeck/outlives/mod.rs
index f0310f250a9bd..b3634d37cc2b8 100644
--- a/src/librustc_typeck/outlives/mod.rs
+++ b/src/librustc_typeck/outlives/mod.rs
@@ -12,7 +12,7 @@ mod implicit_infer;
 pub mod test;
 mod utils;
 
-pub fn provide(providers: &mut Providers) {
+pub fn provide(providers: &mut Providers<'_>) {
     *providers = Providers {
         inferred_outlives_of,
         inferred_outlives_crate,
diff --git a/src/librustc_typeck/structured_errors.rs b/src/librustc_typeck/structured_errors.rs
index 7e1ef8e021350..3e3eab8cf4cfb 100644
--- a/src/librustc_typeck/structured_errors.rs
+++ b/src/librustc_typeck/structured_errors.rs
@@ -63,7 +63,7 @@ impl<'tcx> StructuredDiagnostic<'tcx> for VariadicError<'tcx> {
             )
         };
         if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.span) {
-            err.span_suggestion_with_applicability(
+            err.span_suggestion(
                 self.span,
                 &format!("cast the value to `{}`", self.cast_ty),
                 format!("{} as {}", snippet, self.cast_ty),
@@ -137,7 +137,7 @@ To fix this error, don't try to cast directly between thin and fat
 pointers.
 
 For more information about casts, take a look at The Book:
-https://doc.rust-lang.org/book/first-edition/casting-between-types.html");
+https://doc.rust-lang.org/reference/expressions/operator-expr.html#type-cast-expressions");
         err
     }
 }
diff --git a/src/librustc_typeck/variance/constraints.rs b/src/librustc_typeck/variance/constraints.rs
index 868c1132e44c5..1d407870ee73a 100644
--- a/src/librustc_typeck/variance/constraints.rs
+++ b/src/librustc_typeck/variance/constraints.rs
@@ -41,7 +41,7 @@ pub struct Constraint<'a> {
 ///     }
 ///
 /// then while we are visiting `Bar<T>`, the `CurrentItem` would have
-/// the def-id and the start of `Foo`'s inferreds.
+/// the `DefId` and the start of `Foo`'s inferreds.
 pub struct CurrentItem {
     inferred_start: InferredIndex,
 }
diff --git a/src/librustc_typeck/variance/mod.rs b/src/librustc_typeck/variance/mod.rs
index afb6a68482013..347422780d516 100644
--- a/src/librustc_typeck/variance/mod.rs
+++ b/src/librustc_typeck/variance/mod.rs
@@ -46,12 +46,12 @@ fn crate_variances<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, crate_num: CrateNum)
 
 fn variances_of<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, item_def_id: DefId)
                           -> Lrc<Vec<ty::Variance>> {
-    let id = tcx.hir().as_local_node_id(item_def_id).expect("expected local def-id");
+    let id = tcx.hir().as_local_hir_id(item_def_id).expect("expected local def-id");
     let unsupported = || {
         // Variance not relevant.
-        span_bug!(tcx.hir().span(id), "asked to compute variance for wrong kind of item")
+        span_bug!(tcx.hir().span_by_hir_id(id), "asked to compute variance for wrong kind of item")
     };
-    match tcx.hir().get(id) {
+    match tcx.hir().get_by_hir_id(id) {
         Node::Item(item) => match item.node {
             hir::ItemKind::Enum(..) |
             hir::ItemKind::Struct(..) |
diff --git a/src/librustc_typeck/variance/terms.rs b/src/librustc_typeck/variance/terms.rs
index d53e2d2ad7883..ec0acfb63a89a 100644
--- a/src/librustc_typeck/variance/terms.rs
+++ b/src/librustc_typeck/variance/terms.rs
@@ -15,7 +15,7 @@ use std::fmt;
 use syntax::ast;
 use rustc::hir;
 use rustc::hir::itemlikevisit::ItemLikeVisitor;
-use util::nodemap::NodeMap;
+use crate::util::nodemap::NodeMap;
 
 use self::VarianceTerm::*;
 
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
index 4b421881db48d..20d5e672a8368 100644
--- a/src/librustdoc/Cargo.toml
+++ b/src/librustdoc/Cargo.toml
@@ -9,6 +9,6 @@ path = "lib.rs"
 
 [dependencies]
 pulldown-cmark = { version = "0.1.2", default-features = false }
-minifier = "0.0.26"
+minifier = "0.0.28"
 tempfile = "3"
 parking_lot = "0.6.4"
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 27ca205720d6a..8796cfa01e0ea 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -574,6 +574,10 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
         let mut ty_to_fn: FxHashMap<Type, (Option<PolyTrait>, Option<Type>)> = Default::default();
 
         for (orig_p, p) in clean_where_predicates {
+            if p.is_none() {
+                continue;
+            }
+            let p = p.unwrap();
             match p {
                 WherePredicate::BoundPredicate { ty, mut bounds } => {
                     // Writing a projection trait bound of the form
@@ -769,6 +773,7 @@ impl<'a, 'tcx, 'rcx> AutoTraitFinder<'a, 'tcx, 'rcx> {
                     }
                 }
                 GenericParamDefKind::Lifetime => {}
+                GenericParamDefKind::Const { .. } => {}
             }
         }
 
diff --git a/src/librustdoc/clean/cfg.rs b/src/librustdoc/clean/cfg.rs
index c74a561e5a0d5..adfac98df868b 100644
--- a/src/librustdoc/clean/cfg.rs
+++ b/src/librustdoc/clean/cfg.rs
@@ -1,4 +1,4 @@
-//! Representation of a `#[doc(cfg(...))]` attribute.
+//! The representation of a `#[doc(cfg(...))]` attribute.
 
 // FIXME: Once the portability lint RFC is implemented (see tracking issue #41619),
 // switch to use those structures instead.
@@ -24,7 +24,7 @@ pub enum Cfg {
     False,
     /// A generic configuration option, e.g., `test` or `target_os = "linux"`.
     Cfg(Symbol, Option<Symbol>),
-    /// Negate a configuration requirement, i.e., `not(x)`.
+    /// Negates a configuration requirement, i.e., `not(x)`.
     Not(Box<Cfg>),
     /// Union of a list of configuration requirements, i.e., `any(...)`.
     Any(Vec<Cfg>),
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 9cb21df713e5b..8c8151e1e9509 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -37,8 +37,11 @@ use super::Clean;
 /// and `Some` of a vector of items if it was successfully expanded.
 pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name, visited: &mut FxHashSet<DefId>)
                   -> Option<Vec<clean::Item>> {
-    if def == Def::Err { return None }
-    let did = def.def_id();
+    let did = if let Some(did) = def.opt_def_id() {
+        did
+    } else {
+        return None;
+    };
     if did.is_local() { return None }
     let mut ret = Vec::new();
     let inner = match def {
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 6eea95b61c990..ea9034ae3a1e0 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -165,7 +165,12 @@ impl<'a, 'tcx, 'rcx> Clean<Crate> for visit_ast::RustdocVisitor<'a, 'tcx, 'rcx>
         match module.inner {
             ModuleItem(ref module) => {
                 for it in &module.items {
-                    if it.is_extern_crate() && it.attrs.has_doc_flag("masked") {
+                    // `compiler_builtins` should be masked too, but we can't apply
+                    // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
+                    if it.is_extern_crate()
+                        && (it.attrs.has_doc_flag("masked")
+                            || self.cx.tcx.is_compiler_builtins(it.def_id.krate))
+                    {
                         masked_crates.insert(it.def_id.krate);
                     }
                 }
@@ -517,6 +522,7 @@ pub enum ItemEnum {
     StaticItem(Static),
     ConstantItem(Constant),
     TraitItem(Trait),
+    TraitAliasItem(TraitAlias),
     ImplItem(Impl),
     /// A method signature only. Used for required methods in traits (ie,
     /// non-default-methods).
@@ -554,6 +560,7 @@ impl ItemEnum {
             ItemEnum::TyMethodItem(ref i) => &i.generics,
             ItemEnum::MethodItem(ref i) => &i.generics,
             ItemEnum::ForeignFunctionItem(ref f) => &f.generics,
+            ItemEnum::TraitAliasItem(ref ta) => &ta.generics,
             _ => return None,
         })
     }
@@ -603,6 +610,7 @@ impl Clean<Item> for doctree::Module {
         items.extend(self.impls.iter().flat_map(|x| x.clean(cx)));
         items.extend(self.macros.iter().map(|x| x.clean(cx)));
         items.extend(self.proc_macros.iter().map(|x| x.clean(cx)));
+        items.extend(self.trait_aliases.iter().map(|x| x.clean(cx)));
 
         // determine if we should display the inner contents or
         // the outer `mod` item for the source code.
@@ -685,7 +693,7 @@ impl AttributesExt for [ast::Attribute] {
 }
 
 pub trait NestedAttributesExt {
-    /// Returns whether the attribute list contains a specific `Word`
+    /// Returns `true` if the attribute list contains a specific `Word`
     fn has_word(self, word: &str) -> bool;
 }
 
@@ -937,7 +945,7 @@ impl Attributes {
         }
     }
 
-    /// Get links as a vector
+    /// Gets links as a vector
     ///
     /// Cache must be populated before call
     pub fn links(&self, krate: &CrateNum) -> Vec<(String, String)> {
@@ -1210,8 +1218,7 @@ impl Lifetime {
 impl Clean<Lifetime> for hir::Lifetime {
     fn clean(&self, cx: &DocContext) -> Lifetime {
         if self.id != ast::DUMMY_NODE_ID {
-            let hir_id = cx.tcx.hir().node_to_hir_id(self.id);
-            let def = cx.tcx.named_region(hir_id);
+            let def = cx.tcx.named_region(self.hir_id);
             match def {
                 Some(rl::Region::EarlyBound(_, node_id, _)) |
                 Some(rl::Region::LateBound(_, node_id, _)) |
@@ -1251,6 +1258,15 @@ impl Clean<Lifetime> for hir::GenericParam {
     }
 }
 
+impl Clean<Constant> for hir::ConstArg {
+    fn clean(&self, cx: &DocContext) -> Constant {
+        Constant {
+            type_: cx.tcx.type_of(cx.tcx.hir().body_owner_def_id(self.value.body)).clean(cx),
+            expr: print_const_expr(cx, self.value.body),
+        }
+    }
+}
+
 impl<'tcx> Clean<Lifetime> for ty::GenericParamDef {
     fn clean(&self, _cx: &DocContext) -> Lifetime {
         Lifetime(self.name.to_string())
@@ -1271,7 +1287,10 @@ impl Clean<Option<Lifetime>> for ty::RegionKind {
             ty::RePlaceholder(..) |
             ty::ReEmpty |
             ty::ReClosureBound(_) |
-            ty::ReErased => None
+            ty::ReErased => {
+                debug!("Cannot clean region {:?}", self);
+                None
+            }
         }
     }
 }
@@ -1310,16 +1329,16 @@ impl Clean<WherePredicate> for hir::WherePredicate {
     }
 }
 
-impl<'a> Clean<WherePredicate> for ty::Predicate<'a> {
-    fn clean(&self, cx: &DocContext) -> WherePredicate {
+impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
+    fn clean(&self, cx: &DocContext) -> Option<WherePredicate> {
         use rustc::ty::Predicate;
 
         match *self {
-            Predicate::Trait(ref pred) => pred.clean(cx),
-            Predicate::Subtype(ref pred) => pred.clean(cx),
+            Predicate::Trait(ref pred) => Some(pred.clean(cx)),
+            Predicate::Subtype(ref pred) => Some(pred.clean(cx)),
             Predicate::RegionOutlives(ref pred) => pred.clean(cx),
             Predicate::TypeOutlives(ref pred) => pred.clean(cx),
-            Predicate::Projection(ref pred) => pred.clean(cx),
+            Predicate::Projection(ref pred) => Some(pred.clean(cx)),
 
             Predicate::WellFormed(..) |
             Predicate::ObjectSafe(..) |
@@ -1345,24 +1364,39 @@ impl<'tcx> Clean<WherePredicate> for ty::SubtypePredicate<'tcx> {
     }
 }
 
-impl<'tcx> Clean<WherePredicate> for ty::OutlivesPredicate<ty::Region<'tcx>, ty::Region<'tcx>> {
-    fn clean(&self, cx: &DocContext) -> WherePredicate {
+impl<'tcx> Clean<Option<WherePredicate>> for
+    ty::OutlivesPredicate<ty::Region<'tcx>,ty::Region<'tcx>> {
+
+    fn clean(&self, cx: &DocContext) -> Option<WherePredicate> {
         let ty::OutlivesPredicate(ref a, ref b) = *self;
-        WherePredicate::RegionPredicate {
+
+        match (a, b) {
+            (ty::ReEmpty, ty::ReEmpty) => {
+                return None;
+            },
+            _ => {}
+        }
+
+        Some(WherePredicate::RegionPredicate {
             lifetime: a.clean(cx).expect("failed to clean lifetime"),
             bounds: vec![GenericBound::Outlives(b.clean(cx).expect("failed to clean bounds"))]
-        }
+        })
     }
 }
 
-impl<'tcx> Clean<WherePredicate> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
-    fn clean(&self, cx: &DocContext) -> WherePredicate {
+impl<'tcx> Clean<Option<WherePredicate>> for ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>> {
+    fn clean(&self, cx: &DocContext) -> Option<WherePredicate> {
         let ty::OutlivesPredicate(ref ty, ref lt) = *self;
 
-        WherePredicate::BoundPredicate {
+        match lt {
+            ty::ReEmpty => return None,
+            _ => {}
+        }
+
+        Some(WherePredicate::BoundPredicate {
             ty: ty.clean(cx),
             bounds: vec![GenericBound::Outlives(lt.clean(cx).expect("failed to clean lifetimes"))]
-        }
+        })
     }
 }
 
@@ -1398,6 +1432,10 @@ pub enum GenericParamDefKind {
         default: Option<Type>,
         synthetic: Option<hir::SyntheticTyParamKind>,
     },
+    Const {
+        did: DefId,
+        ty: Type,
+    },
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
@@ -1410,7 +1448,10 @@ pub struct GenericParamDef {
 impl GenericParamDef {
     pub fn is_synthetic_type_param(&self) -> bool {
         match self.kind {
-            GenericParamDefKind::Lifetime => false,
+            GenericParamDefKind::Lifetime |
+            GenericParamDefKind::Const { .. } => {
+                false
+            }
             GenericParamDefKind::Type { ref synthetic, .. } => synthetic.is_some(),
         }
     }
@@ -1466,7 +1507,7 @@ impl Clean<GenericParamDef> for hir::GenericParam {
                 };
                 (name, GenericParamDefKind::Lifetime)
             }
-            hir::GenericParamKind::Type { ref default, synthetic, .. } => {
+            hir::GenericParamKind::Type { ref default, synthetic } => {
                 (self.name.ident().name.clean(cx), GenericParamDefKind::Type {
                     did: cx.tcx.hir().local_def_id(self.id),
                     bounds: self.bounds.clean(cx),
@@ -1474,6 +1515,12 @@ impl Clean<GenericParamDef> for hir::GenericParam {
                     synthetic: synthetic,
                 })
             }
+            hir::GenericParamKind::Const { ref ty } => {
+                (self.name.ident().name.clean(cx), GenericParamDefKind::Const {
+                    did: cx.tcx.hir().local_def_id(self.id),
+                    ty: ty.clean(cx),
+                })
+            }
         };
 
         GenericParamDef {
@@ -1513,6 +1560,7 @@ impl Clean<Generics> for hir::Generics {
                     GenericParamDefKind::Type { did, ref bounds, .. } => {
                         cx.impl_trait_bounds.borrow_mut().insert(did, bounds.clone());
                     }
+                    GenericParamDefKind::Const { .. } => unreachable!(),
                 }
                 param
             })
@@ -1546,6 +1594,7 @@ impl Clean<Generics> for hir::Generics {
                                         break
                                     }
                                 }
+                                GenericParamDefKind::Const { .. } => {}
                             }
                         }
                     }
@@ -1579,7 +1628,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics,
         }).collect::<Vec<GenericParamDef>>();
 
         let mut where_predicates = preds.predicates.iter()
-            .map(|(p, _)| p.clean(cx))
+            .flat_map(|(p, _)| p.clean(cx))
             .collect::<Vec<_>>();
 
         // Type parameters and have a Sized bound by default unless removed with
@@ -1707,6 +1756,30 @@ impl FnDecl {
     pub fn self_type(&self) -> Option<SelfTy> {
         self.inputs.values.get(0).and_then(|v| v.to_self())
     }
+
+    /// Returns the sugared return type for an async function.
+    ///
+    /// For example, if the return type is `impl std::future::Future<Output = i32>`, this function
+    /// will return `i32`.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the return type does not match the expected sugaring for async
+    /// functions.
+    pub fn sugared_async_return_type(&self) -> FunctionRetTy {
+        match &self.output {
+            FunctionRetTy::Return(Type::ImplTrait(bounds)) => {
+                match &bounds[0] {
+                    GenericBound::TraitBound(PolyTrait { trait_, .. }, ..) => {
+                        let bindings = trait_.bindings().unwrap();
+                        FunctionRetTy::Return(bindings[0].ty.clone())
+                    }
+                    _ => panic!("unexpected desugaring of async function"),
+                }
+            }
+            _ => panic!("unexpected desugaring of async function"),
+        }
+    }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
@@ -1868,13 +1941,38 @@ impl Clean<Item> for doctree::Trait {
                 items: self.items.clean(cx),
                 generics: self.generics.clean(cx),
                 bounds: self.bounds.clean(cx),
-                is_spotlight: is_spotlight,
+                is_spotlight,
                 is_auto: self.is_auto.clean(cx),
             }),
         }
     }
 }
 
+#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
+pub struct TraitAlias {
+    pub generics: Generics,
+    pub bounds: Vec<GenericBound>,
+}
+
+impl Clean<Item> for doctree::TraitAlias {
+    fn clean(&self, cx: &DocContext) -> Item {
+        let attrs = self.attrs.clean(cx);
+        Item {
+            name: Some(self.name.clean(cx)),
+            attrs,
+            source: self.whence.clean(cx),
+            def_id: cx.tcx.hir().local_def_id(self.id),
+            visibility: self.vis.clean(cx),
+            stability: self.stab.clean(cx),
+            deprecation: self.depr.clean(cx),
+            inner: TraitAliasItem(TraitAlias {
+                generics: self.generics.clean(cx),
+                bounds: self.bounds.clean(cx),
+            }),
+        }
+    }
+}
+
 impl Clean<bool> for hir::IsAuto {
     fn clean(&self, _: &DocContext) -> bool {
         match *self {
@@ -2130,12 +2228,12 @@ pub struct PolyTrait {
 /// it does not preserve mutability or boxes.
 #[derive(Clone, RustcEncodable, RustcDecodable, PartialEq, Eq, Debug, Hash)]
 pub enum Type {
-    /// structs/enums/traits (most that'd be an hir::TyKind::Path)
+    /// Structs/enums/traits (most that'd be an `hir::TyKind::Path`).
     ResolvedPath {
         path: Path,
         typarams: Option<Vec<GenericBound>>,
         did: DefId,
-        /// true if is a `T::Name` path for associated types
+        /// `true` if is a `T::Name` path for associated types.
         is_generic: bool,
     },
     /// For parameterized types, so the consumer of the JSON don't go
@@ -2206,6 +2304,7 @@ pub enum TypeKind {
     Macro,
     Attr,
     Derive,
+    TraitAlias,
 }
 
 pub trait GetDefId {
@@ -2265,6 +2364,21 @@ impl Type {
             _ => None,
         }
     }
+
+    pub fn bindings(&self) -> Option<&[TypeBinding]> {
+        match *self {
+            ResolvedPath { ref path, .. } => {
+                path.segments.last().and_then(|seg| {
+                    if let GenericArgs::AngleBracketed { ref bindings, .. } = seg.args {
+                        Some(&**bindings)
+                    } else {
+                        None
+                    }
+                })
+            }
+            _ => None
+        }
+    }
 }
 
 impl GetDefId for Type {
@@ -2459,6 +2573,7 @@ impl Clean<Type> for hir::Ty {
                     let provided_params = &path.segments.last().expect("segments were empty");
                     let mut ty_substs = FxHashMap::default();
                     let mut lt_substs = FxHashMap::default();
+                    let mut const_substs = FxHashMap::default();
                     provided_params.with_generic_args(|generic_args| {
                         let mut indices: GenericParamCount = Default::default();
                         for param in generics.params.iter() {
@@ -2467,7 +2582,7 @@ impl Clean<Type> for hir::Ty {
                                     let mut j = 0;
                                     let lifetime = generic_args.args.iter().find_map(|arg| {
                                         match arg {
-                                            GenericArg::Lifetime(lt) => {
+                                            hir::GenericArg::Lifetime(lt) => {
                                                 if indices.lifetimes == j {
                                                     return Some(lt);
                                                 }
@@ -2492,7 +2607,7 @@ impl Clean<Type> for hir::Ty {
                                     let mut j = 0;
                                     let type_ = generic_args.args.iter().find_map(|arg| {
                                         match arg {
-                                            GenericArg::Type(ty) => {
+                                            hir::GenericArg::Type(ty) => {
                                                 if indices.types == j {
                                                     return Some(ty);
                                                 }
@@ -2510,10 +2625,32 @@ impl Clean<Type> for hir::Ty {
                                     }
                                     indices.types += 1;
                                 }
+                                hir::GenericParamKind::Const { .. } => {
+                                    let const_param_def =
+                                        Def::ConstParam(cx.tcx.hir().local_def_id(param.id));
+                                    let mut j = 0;
+                                    let const_ = generic_args.args.iter().find_map(|arg| {
+                                        match arg {
+                                            hir::GenericArg::Const(ct) => {
+                                                if indices.consts == j {
+                                                    return Some(ct);
+                                                }
+                                                j += 1;
+                                                None
+                                            }
+                                            _ => None,
+                                        }
+                                    });
+                                    if let Some(ct) = const_.cloned() {
+                                        const_substs.insert(const_param_def, ct.clean(cx));
+                                    }
+                                    // FIXME(const_generics:defaults)
+                                    indices.consts += 1;
+                                }
                             }
                         }
                     });
-                    return cx.enter_alias(ty_substs, lt_substs, || ty.clean(cx));
+                    return cx.enter_alias(ty_substs, lt_substs, const_substs, || ty.clean(cx));
                 }
                 resolve_type(cx, path.clean(cx), self.id)
             }
@@ -3105,6 +3242,9 @@ impl Clean<GenericArgs> for hir::GenericArgs {
                     GenericArg::Type(ty) => {
                         types.push(ty.clean(cx));
                     }
+                    GenericArg::Const(..) => {
+                        unimplemented!() // FIXME(const_generics)
+                    }
                 }
             }
             GenericArgs::AngleBracketed {
@@ -3692,7 +3832,7 @@ fn name_from_pat(p: &hir::Pat) -> String {
 
     match p.node {
         PatKind::Wild => "_".to_string(),
-        PatKind::Binding(_, _, ident, _) => ident.to_string(),
+        PatKind::Binding(_, _, _, ident, _) => ident.to_string(),
         PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
         PatKind::Struct(ref name, ref fields, etc) => {
             format!("{} {{ {}{} }}", qpath_to_string(name),
@@ -3745,7 +3885,7 @@ fn print_const(cx: &DocContext, n: ty::LazyConst) -> String {
 }
 
 fn print_const_expr(cx: &DocContext, body: hir::BodyId) -> String {
-    cx.tcx.hir().node_to_pretty_string(body.node_id)
+    cx.tcx.hir().hir_to_pretty_string(body.hir_id)
 }
 
 /// Given a type Path, resolve it to a Type using the TyCtxt
@@ -3802,10 +3942,9 @@ pub fn register_def(cx: &DocContext, def: Def) -> DefId {
             MacroKind::Derive => (i, TypeKind::Derive),
             MacroKind::ProcMacroStub => unreachable!(),
         },
+        Def::TraitAlias(i) => (i, TypeKind::TraitAlias),
         Def::SelfTy(Some(def_id), _) => (def_id, TypeKind::Trait),
-        Def::SelfTy(_, Some(impl_def_id)) => {
-            return impl_def_id
-        }
+        Def::SelfTy(_, Some(impl_def_id)) => return impl_def_id,
         _ => return def.def_id()
     };
     if did.is_local() { return did }
@@ -3818,7 +3957,7 @@ pub fn register_def(cx: &DocContext, def: Def) -> DefId {
 
 fn resolve_use_source(cx: &DocContext, path: Path) -> ImportSource {
     ImportSource {
-        did: if path.def == Def::Err {
+        did: if path.def.opt_def_id().is_none() {
             None
         } else {
             Some(register_def(cx, path.def))
@@ -3938,7 +4077,7 @@ impl Clean<Deprecation> for attr::Deprecation {
     }
 }
 
-/// An equality constraint on an associated type, e.g., `A=Bar` in `Foo<A=Bar>`
+/// An equality constraint on an associated type, e.g., `A = Bar` in `Foo<A = Bar>`
 #[derive(Clone, PartialEq, Eq, RustcDecodable, RustcEncodable, Debug, Hash)]
 pub struct TypeBinding {
     pub name: String,
@@ -4071,6 +4210,7 @@ where F: Fn(DefId) -> Def {
         segments: hir::HirVec::from_vec(apb.names.iter().map(|s| hir::PathSegment {
             ident: ast::Ident::from_str(&s),
             id: None,
+            hir_id: None,
             def: None,
             args: None,
             infer_types: false,
diff --git a/src/librustdoc/clean/simplify.rs b/src/librustdoc/clean/simplify.rs
index 31e842b338962..376cf3a2deebe 100644
--- a/src/librustdoc/clean/simplify.rs
+++ b/src/librustdoc/clean/simplify.rs
@@ -1,11 +1,11 @@
-//! Simplification of where clauses and parameter bounds into a prettier and
+//! Simplification of where-clauses and parameter bounds into a prettier and
 //! more canonical form.
 //!
 //! Currently all cross-crate-inlined function use `rustc::ty` to reconstruct
 //! the AST (e.g., see all of `clean::inline`), but this is not always a
-//! non-lossy transformation. The current format of storage for where clauses
+//! non-lossy transformation. The current format of storage for where-clauses
 //! for functions and such is simply a list of predicates. One example of this
-//! is that the AST predicate of: `where T: Trait<Foo=Bar>` is encoded as:
+//! is that the AST predicate of: `where T: Trait<Foo = Bar>` is encoded as:
 //! `where T: Trait, <T as Trait>::Foo = Bar`.
 //!
 //! This module attempts to reconstruct the original where and/or parameter
diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index d99136802514d..91fbe877cb7d9 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -68,6 +68,9 @@ pub struct Options {
     pub should_test: bool,
     /// List of arguments to pass to the test harness, if running tests.
     pub test_args: Vec<String>,
+    /// Optional path to persist the doctest executables to, defaults to a
+    /// temporary directory if not set.
+    pub persist_doctests: Option<PathBuf>,
 
     // Options that affect the documentation process
 
@@ -121,6 +124,7 @@ impl fmt::Debug for Options {
             .field("lint_cap", &self.lint_cap)
             .field("should_test", &self.should_test)
             .field("test_args", &self.test_args)
+            .field("persist_doctests", &self.persist_doctests)
             .field("default_passes", &self.default_passes)
             .field("manual_passes", &self.manual_passes)
             .field("display_warnings", &self.display_warnings)
@@ -146,9 +150,9 @@ pub struct RenderOptions {
     pub playground_url: Option<String>,
     /// Whether to sort modules alphabetically on a module page instead of using declaration order.
     /// `true` by default.
-    ///
-    /// FIXME(misdreavus): the flag name is `--sort-modules-by-appearance` but the meaning is
-    /// inverted once read
+    //
+    // FIXME(misdreavus): the flag name is `--sort-modules-by-appearance` but the meaning is
+    // inverted once read.
     pub sort_modules_alphabetically: bool,
     /// List of themes to extend the docs with. Original argument name is included to assist in
     /// displaying errors if it fails a theme check.
@@ -161,9 +165,9 @@ pub struct RenderOptions {
     pub resource_suffix: String,
     /// Whether to run the static CSS/JavaScript through a minifier when outputting them. `true` by
     /// default.
-    ///
-    /// FIXME(misdreavus): the flag name is `--disable-minification` but the meaning is inverted
-    /// once read
+    //
+    // FIXME(misdreavus): the flag name is `--disable-minification` but the meaning is inverted
+    // once read.
     pub enable_minification: bool,
     /// Whether to create an index page in the root of the output directory. If this is true but
     /// `enable_index_page` is None, generate a static listing of crates instead.
@@ -188,6 +192,8 @@ pub struct RenderOptions {
     /// If false, the `select` element to have search filtering by crates on rendered docs
     /// won't be generated.
     pub generate_search_filter: bool,
+    /// Option (disabled by default) to generate files used by RLS and some other tools.
+    pub generate_redirect_pages: bool,
 }
 
 impl Options {
@@ -431,6 +437,8 @@ impl Options {
         let enable_index_page = matches.opt_present("enable-index-page") || index_page.is_some();
         let static_root_path = matches.opt_str("static-root-path");
         let generate_search_filter = !matches.opt_present("disable-per-crate-search");
+        let persist_doctests = matches.opt_str("persist-doctests").map(PathBuf::from);
+        let generate_redirect_pages = matches.opt_present("generate-redirect-pages");
 
         let (lint_opts, describe_lints, lint_cap) = get_cmd_lint_options(matches, error_format);
 
@@ -456,6 +464,7 @@ impl Options {
             manual_passes,
             display_warnings,
             crate_version,
+            persist_doctests,
             render_options: RenderOptions {
                 output,
                 external_html,
@@ -474,11 +483,12 @@ impl Options {
                 markdown_css,
                 markdown_playground_url,
                 generate_search_filter,
+                generate_redirect_pages,
             }
         })
     }
 
-    /// Returns whether the file given as `self.input` is a Markdown file.
+    /// Returns `true` if the file given as `self.input` is a Markdown file.
     pub fn markdown_input(&self) -> bool {
         self.input.extension()
             .map_or(false, |e| e == "md" || e == "markdown")
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index 78dbf41bf21fd..59820e4e5d1ae 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -51,9 +51,6 @@ pub struct DocContext<'a, 'tcx: 'a, 'rcx: 'a> {
     /// The stack of module NodeIds up till this point
     pub crate_name: Option<String>,
     pub cstore: Rc<CStore>,
-    // Note that external items for which `doc(hidden)` applies to are shown as
-    // non-reachable while local items aren't. This is because we're reusing
-    // the access levels from crateanalysis.
     /// Later on moved into `html::render::CACHE_KEY`
     pub renderinfo: RefCell<RenderInfo>,
     /// Later on moved through `clean::Crate` into `html::render::CACHE_KEY`
@@ -66,8 +63,10 @@ pub struct DocContext<'a, 'tcx: 'a, 'rcx: 'a> {
 
     /// Table type parameter definition -> substituted type
     pub ty_substs: RefCell<FxHashMap<Def, clean::Type>>,
-    /// Table node id of lifetime parameter definition -> substituted lifetime
+    /// Table `NodeId` of lifetime parameter definition -> substituted lifetime
     pub lt_substs: RefCell<FxHashMap<DefId, clean::Lifetime>>,
+    /// Table node id of const parameter definition -> substituted const
+    pub ct_substs: RefCell<FxHashMap<Def, clean::Constant>>,
     /// Table DefId of `impl Trait` in argument position -> bounds
     pub impl_trait_bounds: RefCell<FxHashMap<DefId, Vec<clean::GenericBound>>>,
     pub send_trait: Option<DefId>,
@@ -88,14 +87,18 @@ impl<'a, 'tcx, 'rcx> DocContext<'a, 'tcx, 'rcx> {
     pub fn enter_alias<F, R>(&self,
                              ty_substs: FxHashMap<Def, clean::Type>,
                              lt_substs: FxHashMap<DefId, clean::Lifetime>,
+                             ct_substs: FxHashMap<Def, clean::Constant>,
                              f: F) -> R
     where F: FnOnce() -> R {
-        let (old_tys, old_lts) =
-            (mem::replace(&mut *self.ty_substs.borrow_mut(), ty_substs),
-             mem::replace(&mut *self.lt_substs.borrow_mut(), lt_substs));
+        let (old_tys, old_lts, old_cts) = (
+            mem::replace(&mut *self.ty_substs.borrow_mut(), ty_substs),
+            mem::replace(&mut *self.lt_substs.borrow_mut(), lt_substs),
+            mem::replace(&mut *self.ct_substs.borrow_mut(), ct_substs),
+        );
         let r = f();
         *self.ty_substs.borrow_mut() = old_tys;
         *self.lt_substs.borrow_mut() = old_lts;
+        *self.ct_substs.borrow_mut() = old_cts;
         r
     }
 
@@ -177,6 +180,7 @@ impl<'a, 'tcx, 'rcx> DocContext<'a, 'tcx, 'rcx> {
             real_name.unwrap_or(last.ident),
             None,
             None,
+            None,
             self.generics_to_path_params(generics.clone()),
             false,
         ));
@@ -209,11 +213,12 @@ impl<'a, 'tcx, 'rcx> DocContext<'a, 'tcx, 'rcx> {
 
                     args.push(hir::GenericArg::Lifetime(hir::Lifetime {
                         id: ast::DUMMY_NODE_ID,
+                        hir_id: hir::DUMMY_HIR_ID,
                         span: DUMMY_SP,
                         name: hir::LifetimeName::Param(name),
                     }));
                 }
-                ty::GenericParamDefKind::Type {..} => {
+                ty::GenericParamDefKind::Type { .. } => {
                     args.push(hir::GenericArg::Type(self.ty_param_to_ty(param.clone())));
                 }
             }
@@ -468,15 +473,13 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
             freevars: resolver.freevars.clone(),
             export_map: resolver.export_map.clone(),
             trait_map: resolver.trait_map.clone(),
+            glob_map: resolver.glob_map.clone(),
             maybe_unused_trait_imports: resolver.maybe_unused_trait_imports.clone(),
             maybe_unused_extern_crates: resolver.maybe_unused_extern_crates.clone(),
             extern_prelude: resolver.extern_prelude.iter().map(|(ident, entry)| {
                 (ident.name, entry.introduced_by_item)
             }).collect(),
         };
-        let analysis = ty::CrateAnalysis {
-            glob_map: resolver.glob_map.clone(),
-        };
 
         let mut arenas = AllArenas::new();
         let hir_map = hir_map::map_crate(&sess, &*cstore, &mut hir_forest, &defs);
@@ -492,12 +495,11 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
                                                         &sess,
                                                         &*cstore,
                                                         hir_map,
-                                                        analysis,
                                                         resolutions,
                                                         &mut arenas,
                                                         &name,
                                                         &output_filenames,
-                                                        |tcx, _, _, result| {
+                                                        |tcx, _, result| {
             if result.is_err() {
                 sess.fatal("Compilation failed, aborting rustdoc");
             }
@@ -531,6 +533,7 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
                 renderinfo: RefCell::new(renderinfo),
                 ty_substs: Default::default(),
                 lt_substs: Default::default(),
+                ct_substs: Default::default(),
                 impl_trait_bounds: Default::default(),
                 send_trait: send_trait,
                 fake_def_ids: Default::default(),
diff --git a/src/librustdoc/doctree.rs b/src/librustdoc/doctree.rs
index cc27da70b16d7..e8458385739df 100644
--- a/src/librustdoc/doctree.rs
+++ b/src/librustdoc/doctree.rs
@@ -38,6 +38,7 @@ pub struct Module {
     pub foreigns: Vec<hir::ForeignMod>,
     pub macros: Vec<Macro>,
     pub proc_macros: Vec<ProcMacro>,
+    pub trait_aliases: Vec<TraitAlias>,
     pub is_crate: bool,
 }
 
@@ -53,21 +54,22 @@ impl Module {
             where_inner: syntax_pos::DUMMY_SP,
             attrs      : hir::HirVec::new(),
             extern_crates: Vec::new(),
-            imports    : Vec::new(),
-            structs    : Vec::new(),
-            unions     : Vec::new(),
-            enums      : Vec::new(),
-            fns        : Vec::new(),
-            mods       : Vec::new(),
-            typedefs   : Vec::new(),
-            existentials: Vec::new(),
-            statics    : Vec::new(),
-            constants  : Vec::new(),
-            traits     : Vec::new(),
-            impls      : Vec::new(),
-            foreigns   : Vec::new(),
-            macros     : Vec::new(),
-            proc_macros: Vec::new(),
+            imports    :   Vec::new(),
+            structs    :   Vec::new(),
+            unions     :   Vec::new(),
+            enums      :   Vec::new(),
+            fns        :   Vec::new(),
+            mods       :   Vec::new(),
+            typedefs   :   Vec::new(),
+            existentials:  Vec::new(),
+            statics    :   Vec::new(),
+            constants  :   Vec::new(),
+            traits     :   Vec::new(),
+            impls      :   Vec::new(),
+            foreigns   :   Vec::new(),
+            macros     :   Vec::new(),
+            proc_macros:   Vec::new(),
+            trait_aliases: Vec::new(),
             is_crate   : false,
         }
     }
@@ -208,6 +210,18 @@ pub struct Trait {
     pub depr: Option<attr::Deprecation>,
 }
 
+pub struct TraitAlias {
+    pub name: Name,
+    pub generics: hir::Generics,
+    pub bounds: hir::HirVec<hir::GenericBound>,
+    pub attrs: hir::HirVec<ast::Attribute>,
+    pub id: ast::NodeId,
+    pub whence: Span,
+    pub vis: hir::Visibility,
+    pub stab: Option<attr::Stability>,
+    pub depr: Option<attr::Deprecation>,
+}
+
 #[derive(Debug)]
 pub struct Impl {
     pub unsafety: hir::Unsafety,
diff --git a/src/librustdoc/html/escape.rs b/src/librustdoc/html/escape.rs
index 690bcd8c070cf..35858d8415075 100644
--- a/src/librustdoc/html/escape.rs
+++ b/src/librustdoc/html/escape.rs
@@ -1,6 +1,6 @@
-//! HTML Escaping
+//! HTML escaping.
 //!
-//! This module contains one unit-struct which can be used to HTML-escape a
+//! This module contains one unit struct, which can be used to HTML-escape a
 //! string of text (for use in a format string).
 
 use std::fmt;
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 5a3e6984859a2..df7835214ebb6 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -5,6 +5,7 @@
 //! assume that HTML output is desired, although it may be possible to redesign
 //! them in the future to instead emit any format desired.
 
+use std::borrow::Cow;
 use std::fmt;
 
 use rustc::hir::def_id::DefId;
@@ -44,23 +45,28 @@ pub struct GenericBounds<'a>(pub &'a [clean::GenericBound]);
 pub struct CommaSep<'a, T: 'a>(pub &'a [T]);
 pub struct AbiSpace(pub Abi);
 
-/// Wrapper struct for properly emitting a method declaration.
-pub struct Method<'a> {
+/// Wrapper struct for properly emitting a function or method declaration.
+pub struct Function<'a> {
     /// The declaration to emit.
     pub decl: &'a clean::FnDecl,
-    /// The length of the function's "name", used to determine line-wrapping.
-    pub name_len: usize,
+    /// The length of the function header and name. In other words, the number of characters in the
+    /// function declaration up to but not including the parentheses.
+    ///
+    /// Used to determine line-wrapping.
+    pub header_len: usize,
     /// The number of spaces to indent each successive line with, if line-wrapping is necessary.
     pub indent: usize,
+    /// Whether the function is async or not.
+    pub asyncness: hir::IsAsync,
 }
 
-/// Wrapper struct for emitting a where clause from Generics.
+/// Wrapper struct for emitting a where-clause from Generics.
 pub struct WhereClause<'a>{
-    /// The Generics from which to emit a where clause.
+    /// The Generics from which to emit a where-clause.
     pub gens: &'a clean::Generics,
     /// The number of spaces to indent each line with.
     pub indent: usize,
-    /// Whether the where clause needs to add a comma and newline after the last bound.
+    /// Whether the where-clause needs to add a comma and newline after the last bound.
     pub end_newline: bool,
 }
 
@@ -135,6 +141,16 @@ impl fmt::Display for clean::GenericParamDef {
 
                 Ok(())
             }
+            clean::GenericParamDefKind::Const { ref ty, .. } => {
+                f.write_str("const ")?;
+                f.write_str(&self.name)?;
+
+                if f.alternate() {
+                    write!(f, ": {:#}", ty)
+                } else {
+                    write!(f, ":&nbsp;{}", ty)
+                }
+            }
         }
     }
 }
@@ -662,7 +678,11 @@ fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt:
             }
         }
         clean::ImplTrait(ref bounds) => {
-            write!(f, "impl {}", GenericBounds(bounds))
+            if f.alternate() {
+                write!(f, "impl {:#}", GenericBounds(bounds))
+            } else {
+                write!(f, "impl {}", GenericBounds(bounds))
+            }
         }
         clean::QPath { ref name, ref self_type, ref trait_ } => {
             let should_show_cast = match *trait_ {
@@ -829,9 +849,9 @@ impl fmt::Display for clean::FnDecl {
     }
 }
 
-impl<'a> fmt::Display for Method<'a> {
+impl<'a> fmt::Display for Function<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let &Method { decl, name_len, indent } = self;
+        let &Function { decl, header_len, indent, asyncness } = self;
         let amp = if f.alternate() { "&" } else { "&amp;" };
         let mut args = String::new();
         let mut args_plain = String::new();
@@ -886,25 +906,28 @@ impl<'a> fmt::Display for Method<'a> {
             }
         }
 
+        let mut args_plain = format!("({})", args_plain);
+
         if decl.variadic {
             args.push_str(",<br> ...");
             args_plain.push_str(", ...");
         }
 
-        let arrow_plain = format!("{:#}", decl.output);
-        let arrow = if f.alternate() {
-            format!("{:#}", decl.output)
+        let output = if let hir::IsAsync::Async = asyncness {
+            Cow::Owned(decl.sugared_async_return_type())
         } else {
-            decl.output.to_string()
+            Cow::Borrowed(&decl.output)
         };
 
-        let pad = " ".repeat(name_len);
-        let plain = format!("{pad}({args}){arrow}",
-                        pad = pad,
-                        args = args_plain,
-                        arrow = arrow_plain);
+        let arrow_plain = format!("{:#}", &output);
+        let arrow = if f.alternate() {
+            format!("{:#}", &output)
+        } else {
+            output.to_string()
+        };
 
-        let output = if plain.len() > 80 {
+        let declaration_len = header_len + args_plain.len() + arrow_plain.len();
+        let output = if declaration_len > 80 {
             let full_pad = format!("<br>{}", "&nbsp;".repeat(indent + 4));
             let close_pad = format!("<br>{}", "&nbsp;".repeat(indent));
             format!("({args}{close}){arrow}",
diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
index 87e979b93e9ef..66b1b5b4d7547 100644
--- a/src/librustdoc/html/highlight.rs
+++ b/src/librustdoc/html/highlight.rs
@@ -25,40 +25,51 @@ pub fn render_with_highlighting(
     tooltip: Option<(&str, &str)>,
 ) -> String {
     debug!("highlighting: ================\n{}\n==============", src);
-    let sess = parse::ParseSess::new(FilePathMapping::empty());
-    let fm = sess.source_map().new_source_file(FileName::Custom("stdin".to_string()),
-                                               src.to_string());
-
     let mut out = Vec::new();
     if let Some((tooltip, class)) = tooltip {
         write!(out, "<div class='information'><div class='tooltip {}'>ⓘ<span \
                      class='tooltiptext'>{}</span></div></div>",
                class, tooltip).unwrap();
     }
-    write_header(class, &mut out).unwrap();
-
-    let lexer = match lexer::StringReader::new_without_err(&sess, fm, None, "Output from rustc:") {
-        Ok(l) => l,
-        Err(_) => {
-            let first_line = src.lines().next().unwrap_or_else(|| "");
-            let mut err = sess.span_diagnostic
-                              .struct_warn(&format!("Invalid doc comment starting with: `{}`\n\
-                                                     (Ignoring this codeblock)",
-                                                    first_line));
-            err.emit();
-            return String::new();
+
+    let sess = parse::ParseSess::new(FilePathMapping::empty());
+    let fm = sess.source_map().new_source_file(
+        FileName::Custom(String::from("rustdoc-highlighting")),
+        src.to_owned(),
+    );
+    let highlight_result =
+        lexer::StringReader::new_or_buffered_errs(&sess, fm, None).and_then(|lexer| {
+            let mut classifier = Classifier::new(lexer, sess.source_map());
+
+            let mut highlighted_source = vec![];
+            if classifier.write_source(&mut highlighted_source).is_err() {
+                Err(classifier.lexer.buffer_fatal_errors())
+            } else {
+                Ok(String::from_utf8_lossy(&highlighted_source).into_owned())
+            }
+        });
+
+    match highlight_result {
+        Ok(highlighted_source) => {
+            write_header(class, &mut out).unwrap();
+            write!(out, "{}", highlighted_source).unwrap();
+            if let Some(extension) = extension {
+                write!(out, "{}", extension).unwrap();
+            }
+            write_footer(&mut out).unwrap();
         }
-    };
-    let mut classifier = Classifier::new(lexer, sess.source_map());
-    if classifier.write_source(&mut out).is_err() {
-        classifier.lexer.emit_fatal_errors();
-        return format!("<pre>{}</pre>", src);
-    }
+        Err(errors) => {
+            // If errors are encountered while trying to highlight, cancel the errors and just emit
+            // the unhighlighted source. The errors will have already been reported in the
+            // `check-code-block-syntax` pass.
+            for mut error in errors {
+                error.cancel();
+            }
 
-    if let Some(extension) = extension {
-        write!(out, "{}", extension).unwrap();
+            write!(out, "<pre><code>{}</code></pre>", src).unwrap();
+        }
     }
-    write_footer(&mut out).unwrap();
+
     String::from_utf8_lossy(&out[..]).into_owned()
 }
 
@@ -113,7 +124,7 @@ trait Writer {
     /// Called at the end of a span of highlighted text.
     fn exit_span(&mut self) -> io::Result<()>;
 
-    /// Called for a span of text.  If the text should be highlighted differently from the
+    /// Called for a span of text. If the text should be highlighted differently from the
     /// surrounding text, then the `Class` argument will be a value other than `None`.
     ///
     /// The following sequences of callbacks are equivalent:
@@ -151,6 +162,17 @@ impl<U: Write> Writer for U {
     }
 }
 
+enum HighlightError {
+    LexError,
+    IoError(io::Error),
+}
+
+impl From<io::Error> for HighlightError {
+    fn from(err: io::Error) -> Self {
+        HighlightError::IoError(err)
+    }
+}
+
 impl<'a> Classifier<'a> {
     fn new(lexer: lexer::StringReader<'a>, source_map: &'a SourceMap) -> Classifier<'a> {
         Classifier {
@@ -162,17 +184,11 @@ impl<'a> Classifier<'a> {
         }
     }
 
-    /// Gets the next token out of the lexer, emitting fatal errors if lexing fails.
-    fn try_next_token(&mut self) -> io::Result<TokenAndSpan> {
+    /// Gets the next token out of the lexer.
+    fn try_next_token(&mut self) -> Result<TokenAndSpan, HighlightError> {
         match self.lexer.try_next_token() {
             Ok(tas) => Ok(tas),
-            Err(_) => {
-                let mut err = self.lexer.sess.span_diagnostic
-                                  .struct_warn("Backing out of syntax highlighting");
-                err.note("You probably did not intend to render this as a rust code-block");
-                err.emit();
-                Err(io::Error::new(io::ErrorKind::Other, ""))
-            }
+            Err(_) => Err(HighlightError::LexError),
         }
     }
 
@@ -185,7 +201,7 @@ impl<'a> Classifier<'a> {
     /// source.
     fn write_source<W: Writer>(&mut self,
                                    out: &mut W)
-                                   -> io::Result<()> {
+                                   -> Result<(), HighlightError> {
         loop {
             let next = self.try_next_token()?;
             if next.tok == token::Eof {
@@ -202,7 +218,7 @@ impl<'a> Classifier<'a> {
     fn write_token<W: Writer>(&mut self,
                               out: &mut W,
                               tas: TokenAndSpan)
-                              -> io::Result<()> {
+                              -> Result<(), HighlightError> {
         let klass = match tas.tok {
             token::Shebang(s) => {
                 out.string(Escape(&s.as_str()), Class::None)?;
@@ -296,7 +312,7 @@ impl<'a> Classifier<'a> {
             token::Literal(lit, _suf) => {
                 match lit {
                     // Text literals.
-                    token::Byte(..) | token::Char(..) |
+                    token::Byte(..) | token::Char(..) | token::Err(..) |
                         token::ByteStr(..) | token::ByteStrRaw(..) |
                         token::Str_(..) | token::StrRaw(..) => Class::String,
 
@@ -341,7 +357,9 @@ impl<'a> Classifier<'a> {
 
         // Anything that didn't return above is the simple case where we the
         // class just spans a single token, so we can use the `string` method.
-        out.string(Escape(&self.snip(tas.sp)), klass)
+        out.string(Escape(&self.snip(tas.sp)), klass)?;
+
+        Ok(())
     }
 
     // Helper function to get a snippet from the source_map.
diff --git a/src/librustdoc/html/item_type.rs b/src/librustdoc/html/item_type.rs
index e20d385c487b3..8a3b5484f395d 100644
--- a/src/librustdoc/html/item_type.rs
+++ b/src/librustdoc/html/item_type.rs
@@ -42,6 +42,7 @@ pub enum ItemType {
     Existential     = 22,
     ProcAttribute   = 23,
     ProcDerive      = 24,
+    TraitAlias      = 25,
 }
 
 
@@ -86,6 +87,7 @@ impl<'a> From<&'a clean::Item> for ItemType {
             clean::AssociatedTypeItem(..)  => ItemType::AssociatedType,
             clean::ForeignTypeItem         => ItemType::ForeignType,
             clean::KeywordItem(..)         => ItemType::Keyword,
+            clean::TraitAliasItem(..)      => ItemType::TraitAlias,
             clean::ProcMacroItem(ref mac)  => match mac.kind {
                 MacroKind::Bang            => ItemType::Macro,
                 MacroKind::Attr            => ItemType::ProcAttribute,
@@ -100,20 +102,21 @@ impl<'a> From<&'a clean::Item> for ItemType {
 impl From<clean::TypeKind> for ItemType {
     fn from(kind: clean::TypeKind) -> ItemType {
         match kind {
-            clean::TypeKind::Struct   => ItemType::Struct,
-            clean::TypeKind::Union    => ItemType::Union,
-            clean::TypeKind::Enum     => ItemType::Enum,
-            clean::TypeKind::Function => ItemType::Function,
-            clean::TypeKind::Trait    => ItemType::Trait,
-            clean::TypeKind::Module   => ItemType::Module,
-            clean::TypeKind::Static   => ItemType::Static,
-            clean::TypeKind::Const    => ItemType::Constant,
-            clean::TypeKind::Variant  => ItemType::Variant,
-            clean::TypeKind::Typedef  => ItemType::Typedef,
-            clean::TypeKind::Foreign  => ItemType::ForeignType,
-            clean::TypeKind::Macro    => ItemType::Macro,
-            clean::TypeKind::Attr     => ItemType::ProcAttribute,
-            clean::TypeKind::Derive   => ItemType::ProcDerive,
+            clean::TypeKind::Struct     => ItemType::Struct,
+            clean::TypeKind::Union      => ItemType::Union,
+            clean::TypeKind::Enum       => ItemType::Enum,
+            clean::TypeKind::Function   => ItemType::Function,
+            clean::TypeKind::Trait      => ItemType::Trait,
+            clean::TypeKind::Module     => ItemType::Module,
+            clean::TypeKind::Static     => ItemType::Static,
+            clean::TypeKind::Const      => ItemType::Constant,
+            clean::TypeKind::Variant    => ItemType::Variant,
+            clean::TypeKind::Typedef    => ItemType::Typedef,
+            clean::TypeKind::Foreign    => ItemType::ForeignType,
+            clean::TypeKind::Macro      => ItemType::Macro,
+            clean::TypeKind::Attr       => ItemType::ProcAttribute,
+            clean::TypeKind::Derive     => ItemType::ProcDerive,
+            clean::TypeKind::TraitAlias => ItemType::TraitAlias,
         }
     }
 }
@@ -146,6 +149,7 @@ impl ItemType {
             ItemType::Existential     => "existential",
             ItemType::ProcAttribute   => "attr",
             ItemType::ProcDerive      => "derive",
+            ItemType::TraitAlias      => "traitalias",
         }
     }
 
@@ -160,6 +164,7 @@ impl ItemType {
             ItemType::Primitive |
             ItemType::AssociatedType |
             ItemType::Existential |
+            ItemType::TraitAlias |
             ItemType::ForeignType => NameSpace::Type,
 
             ItemType::ExternCrate |
diff --git a/src/librustdoc/html/layout.rs b/src/librustdoc/html/layout.rs
index 987cec6fbfa96..b444993c1b5ec 100644
--- a/src/librustdoc/html/layout.rs
+++ b/src/librustdoc/html/layout.rs
@@ -4,6 +4,8 @@ use std::path::PathBuf;
 
 use externalfiles::ExternalHtml;
 
+use html::render::SlashChecker;
+
 #[derive(Clone)]
 pub struct Layout {
     pub logo: String,
@@ -176,19 +178,30 @@ pub fn render<T: fmt::Display, S: fmt::Display>(
     static_root_path = static_root_path,
     root_path = page.root_path,
     css_class = page.css_class,
-    logo      = if layout.logo.is_empty() {
-        String::new()
-    } else {
-        format!("<a href='{}{}/index.html'>\
-                 <img src='{}' alt='logo' width='100'></a>",
-                page.root_path, layout.krate,
-                layout.logo)
+    logo      = {
+        let p = format!("{}{}", page.root_path, layout.krate);
+        let p = SlashChecker(&p);
+        if layout.logo.is_empty() {
+            format!("<a href='{path}index.html'>\
+                     <img src='{static_root_path}rust-logo{suffix}.png' \
+                          alt='logo' width='100'></a>",
+                    path=p,
+                    static_root_path=static_root_path,
+                    suffix=page.resource_suffix)
+        } else {
+            format!("<a href='{}index.html'>\
+                     <img src='{}' alt='logo' width='100'></a>",
+                    p,
+                    layout.logo)
+        }
     },
     title     = page.title,
     description = page.description,
     keywords = page.keywords,
     favicon   = if layout.favicon.is_empty() {
-        String::new()
+        format!(r#"<link rel="shortcut icon" href="{static_root_path}favicon{suffix}.ico">"#,
+                static_root_path=static_root_path,
+                suffix=page.resource_suffix)
     } else {
         format!(r#"<link rel="shortcut icon" href="{}">"#, layout.favicon)
     },
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index 05a9a2d1312ae..386480313dc4c 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -1,8 +1,8 @@
-//! Markdown formatting for rustdoc
+//! Markdown formatting for rustdoc.
 //!
 //! This module implements markdown formatting through the pulldown-cmark
 //! rust-library. This module exposes all of the
-//! functionality through a unit-struct, `Markdown`, which has an implementation
+//! functionality through a unit struct, `Markdown`, which has an implementation
 //! of `fmt::Display`. Example usage:
 //!
 //! ```
@@ -139,7 +139,7 @@ thread_local!(pub static PLAYGROUND: RefCell<Option<(Option<String>, String)>> =
     RefCell::new(None)
 });
 
-/// Adds syntax highlighting and playground Run buttons to rust code blocks.
+/// Adds syntax highlighting and playground Run buttons to Rust code blocks.
 struct CodeBlocks<'a, I: Iterator<Item = Event<'a>>> {
     inner: I,
     check_error_codes: ErrorCodes,
@@ -277,7 +277,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'a, I> {
     }
 }
 
-/// Make headings links with anchor ids and build up TOC.
+/// Make headings links with anchor IDs and build up TOC.
 struct LinkReplacer<'a, 'b, I: Iterator<Item = Event<'a>>> {
     inner: I,
     links: &'b [(String, String)],
@@ -310,7 +310,7 @@ impl<'a, 'b, I: Iterator<Item = Event<'a>>> Iterator for LinkReplacer<'a, 'b, I>
     }
 }
 
-/// Make headings links with anchor ids and build up TOC.
+/// Make headings links with anchor IDs and build up TOC.
 struct HeadingLinks<'a, 'b, 'ids, I: Iterator<Item = Event<'a>>> {
     inner: I,
     toc: Option<&'b mut TocBuilder>,
@@ -919,6 +919,115 @@ pub fn markdown_links(md: &str) -> Vec<(String, Option<Range<usize>>)> {
     links
 }
 
+#[derive(Debug)]
+crate struct RustCodeBlock {
+    /// The range in the markdown that the code block occupies. Note that this includes the fences
+    /// for fenced code blocks.
+    pub range: Range<usize>,
+    /// The range in the markdown that the code within the code block occupies.
+    pub code: Range<usize>,
+    pub is_fenced: bool,
+    pub syntax: Option<String>,
+}
+
+/// Returns a range of bytes for each code block in the markdown that is tagged as `rust` or
+/// untagged (and assumed to be rust).
+crate fn rust_code_blocks(md: &str) -> Vec<RustCodeBlock> {
+    let mut code_blocks = vec![];
+
+    if md.is_empty() {
+        return code_blocks;
+    }
+
+    let mut opts = Options::empty();
+    opts.insert(OPTION_ENABLE_TABLES);
+    opts.insert(OPTION_ENABLE_FOOTNOTES);
+    let mut p = Parser::new_ext(md, opts);
+
+    let mut code_block_start = 0;
+    let mut code_start = 0;
+    let mut is_fenced = false;
+    let mut previous_offset = 0;
+    let mut in_rust_code_block = false;
+    while let Some(event) = p.next() {
+        let offset = p.get_offset();
+
+        match event {
+            Event::Start(Tag::CodeBlock(syntax)) => {
+                let lang_string = if syntax.is_empty() {
+                    LangString::all_false()
+                } else {
+                    LangString::parse(&*syntax, ErrorCodes::Yes)
+                };
+
+                if lang_string.rust {
+                    in_rust_code_block = true;
+
+                    code_start = offset;
+                    code_block_start = match md[previous_offset..offset].find("```") {
+                        Some(fence_idx) => {
+                            is_fenced = true;
+                            previous_offset + fence_idx
+                        }
+                        None => offset,
+                    };
+                }
+            }
+            Event::End(Tag::CodeBlock(syntax)) if in_rust_code_block => {
+                in_rust_code_block = false;
+
+                let code_block_end = if is_fenced {
+                    let fence_str = &md[previous_offset..offset]
+                        .chars()
+                        .rev()
+                        .collect::<String>();
+                    fence_str
+                        .find("```")
+                        .map(|fence_idx| offset - fence_idx)
+                        .unwrap_or_else(|| offset)
+                } else if md
+                    .as_bytes()
+                    .get(offset)
+                    .map(|b| *b == b'\n')
+                    .unwrap_or_default()
+                {
+                    offset - 1
+                } else {
+                    offset
+                };
+
+                let code_end = if is_fenced {
+                    previous_offset
+                } else {
+                    code_block_end
+                };
+
+                code_blocks.push(RustCodeBlock {
+                    is_fenced,
+                    range: Range {
+                        start: code_block_start,
+                        end: code_block_end,
+                    },
+                    code: Range {
+                        start: code_start,
+                        end: code_end,
+                    },
+                    syntax: if !syntax.is_empty() {
+                        Some(syntax.into_owned())
+                    } else {
+                        None
+                    },
+                });
+            }
+            _ => (),
+        }
+
+        previous_offset = offset;
+    }
+
+    code_blocks
+}
+
 #[derive(Clone, Default, Debug)]
 pub struct IdMap {
     map: FxHashMap<String, usize>,
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 3a64c56fc8eeb..d037154272db6 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -1,4 +1,4 @@
-//! Rustdoc's HTML Rendering module
+//! Rustdoc's HTML rendering module.
 //!
 //! This modules contains the bulk of the logic necessary for rendering a
 //! rustdoc `clean::Crate` instance to a set of static HTML pages. This
@@ -62,7 +62,7 @@ use fold::DocFolder;
 use html::escape::Escape;
 use html::format::{AsyncSpace, ConstnessSpace};
 use html::format::{GenericBounds, WhereClause, href, AbiSpace};
-use html::format::{VisSpace, Method, UnsafetySpace, MutableSpace};
+use html::format::{VisSpace, Function, UnsafetySpace, MutableSpace};
 use html::format::fmt_impl_for_trait_page;
 use html::item_type::ItemType;
 use html::markdown::{self, Markdown, MarkdownHtml, MarkdownSummaryLine, ErrorCodes, IdMap};
@@ -73,6 +73,18 @@ use minifier;
 /// A pair of name and its optional document.
 pub type NameDoc = (String, Option<String>);
 
+pub struct SlashChecker<'a>(pub &'a str);
+
+impl<'a> Display for SlashChecker<'a> {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        if !self.0.ends_with("/") && !self.0.is_empty() {
+            write!(f, "{}/", self.0)
+        } else {
+            write!(f, "{}", self.0)
+        }
+    }
+}
+
 /// Major driving force in all rustdoc rendering. This contains information
 /// about where in the tree-like hierarchy rendering is occurring and controls
 /// how the current page is being rendered.
@@ -136,6 +148,8 @@ struct SharedContext {
     /// If false, the `select` element to have search filtering by crates on rendered docs
     /// won't be generated.
     pub generate_search_filter: bool,
+    /// Option disabled by default to generate files used by RLS and some other tools.
+    pub generate_redirect_pages: bool,
 }
 
 impl SharedContext {
@@ -151,7 +165,7 @@ impl SharedContext {
 }
 
 impl SharedContext {
-    /// Returns whether the `collapse-docs` pass was run on this crate.
+    /// Returns `true` if the `collapse-docs` pass was run on this crate.
     pub fn was_collapsed(&self) -> bool {
         self.passes.contains("collapse-docs")
     }
@@ -255,11 +269,11 @@ macro_rules! try_err {
 #[derive(Default)]
 pub struct Cache {
     /// Mapping of typaram ids to the name of the type parameter. This is used
-    /// when pretty-printing a type (so pretty printing doesn't have to
+    /// when pretty-printing a type (so pretty-printing doesn't have to
     /// painfully maintain a context like this)
     pub typarams: FxHashMap<DefId, String>,
 
-    /// Maps a type id to all known implementations for that type. This is only
+    /// Maps a type ID to all known implementations for that type. This is only
     /// recognized for intra-crate `ResolvedPath` types, and is used to print
     /// out extra documentation on the page of an enum/struct.
     ///
@@ -267,7 +281,7 @@ pub struct Cache {
     /// found on that implementation.
     pub impls: FxHashMap<DefId, Vec<Impl>>,
 
-    /// Maintains a mapping of local crate node ids to the fully qualified name
+    /// Maintains a mapping of local crate `NodeId`s to the fully qualified name
     /// and "short type description" of that node. This is used when generating
     /// URLs when a type is being linked to. External paths are not located in
     /// this map because the `External` type itself has all the information
@@ -278,7 +292,7 @@ pub struct Cache {
     /// generating explicit hyperlinks to other crates.
     pub external_paths: FxHashMap<DefId, (Vec<String>, ItemType)>,
 
-    /// Maps local def ids of exported types to fully qualified paths.
+    /// Maps local `DefId`s of exported types to fully qualified paths.
     /// Unlike 'paths', this mapping ignores any renames that occur
     /// due to 'use' statements.
     ///
@@ -309,7 +323,7 @@ pub struct Cache {
 
     // Note that external items for which `doc(hidden)` applies to are shown as
     // non-reachable while local items aren't. This is because we're reusing
-    // the access levels from crateanalysis.
+    // the access levels from the privacy check pass.
     pub access_levels: AccessLevels<DefId>,
 
     /// The version of the crate being documented, if given from the `--crate-version` flag.
@@ -504,6 +518,7 @@ pub fn run(mut krate: clean::Crate,
         resource_suffix,
         static_root_path,
         generate_search_filter,
+        generate_redirect_pages,
         ..
     } = options;
 
@@ -533,6 +548,7 @@ pub fn run(mut krate: clean::Crate,
         resource_suffix,
         static_root_path,
         generate_search_filter,
+        generate_redirect_pages,
     };
 
     // If user passed in `--playground-url` arg, we fill in crate name here
@@ -680,7 +696,7 @@ pub fn run(mut krate: clean::Crate,
     cx.krate(krate)
 }
 
-/// Build the search index from the collected metadata
+/// Builds the search index from the collected metadata
 fn build_index(krate: &clean::Crate, cache: &mut Cache) -> String {
     let mut nodeid_to_pathid = FxHashMap::default();
     let mut crate_items = Vec::with_capacity(cache.search_index.len());
@@ -789,6 +805,14 @@ fn write_shared(
         themes.insert(theme.to_owned());
     }
 
+    if (*cx.shared).layout.logo.is_empty() {
+        write(cx.dst.join(&format!("rust-logo{}.png", cx.shared.resource_suffix)),
+              static_files::RUST_LOGO)?;
+    }
+    if (*cx.shared).layout.favicon.is_empty() {
+        write(cx.dst.join(&format!("favicon{}.ico", cx.shared.resource_suffix)),
+              static_files::RUST_FAVICON)?;
+    }
     write(cx.dst.join(&format!("brush{}.svg", cx.shared.resource_suffix)),
           static_files::BRUSH_SVG)?;
     write(cx.dst.join(&format!("wheel{}.svg", cx.shared.resource_suffix)),
@@ -931,7 +955,7 @@ themePicker.onblur = handleThemeButtonsBlur;
         if path.exists() {
             for line in BufReader::new(File::open(path)?).lines() {
                 let line = line?;
-                if for_search_index && line.starts_with("var r_") {
+                if for_search_index && line.starts_with("var R") {
                     variables.push(line.clone());
                     // We need to check if the crate name has been put into a variable as well.
                     let tokens = js::simple_minify(&line).apply(js::clean_tokens);
@@ -1076,7 +1100,7 @@ themePicker.onblur = handleThemeButtonsBlur;
         all_sources.sort();
         let mut w = try_err!(File::create(&dst), &dst);
         try_err!(writeln!(&mut w,
-                          "var N = null;var sourcesIndex = {{}};\n{}",
+                          "var N = null;var sourcesIndex = {{}};\n{}\ncreateSourceSidebar();",
                           all_sources.join("\n")),
                  &dst);
     }
@@ -1132,7 +1156,8 @@ themePicker.onblur = handleThemeButtonsBlur;
                                   krates
                                     .iter()
                                     .map(|s| {
-                                        format!("<li><a href=\"{}/index.html\">{}</li>", s, s)
+                                        format!("<li><a href=\"{}index.html\">{}</li>",
+                                                SlashChecker(s), s)
                                     })
                                     .collect::<String>());
             try_err!(layout::render(&mut w, &cx.shared.layout,
@@ -1291,8 +1316,9 @@ fn write_minify_replacer<W: Write>(
                               })
                               .apply(|f| {
                                   // We add a backline after the newly created variables.
-                                  minifier::js::aggregate_strings_with_separation(
+                                  minifier::js::aggregate_strings_into_array_with_separation(
                                       f,
+                                      "R",
                                       Token::Char(ReservedChar::Backline),
                                   )
                               })
@@ -1724,7 +1750,8 @@ impl<'a> Cache {
         for param in &generics.params {
             match param.kind {
                 clean::GenericParamDefKind::Lifetime => {}
-                clean::GenericParamDefKind::Type { did, .. } => {
+                clean::GenericParamDefKind::Type { did, .. } |
+                clean::GenericParamDefKind::Const { did, .. } => {
                     self.typarams.insert(did, param.name.clone());
                 }
             }
@@ -1814,6 +1841,7 @@ struct AllTypes {
     keywords: FxHashSet<ItemEntry>,
     attributes: FxHashSet<ItemEntry>,
     derives: FxHashSet<ItemEntry>,
+    trait_aliases: FxHashSet<ItemEntry>,
 }
 
 impl AllTypes {
@@ -1834,6 +1862,7 @@ impl AllTypes {
             keywords: new_set(100),
             attributes: new_set(100),
             derives: new_set(100),
+            trait_aliases: new_set(100),
         }
     }
 
@@ -1857,6 +1886,7 @@ impl AllTypes {
                 ItemType::Constant => self.constants.insert(ItemEntry::new(new_url, name)),
                 ItemType::ProcAttribute => self.attributes.insert(ItemEntry::new(new_url, name)),
                 ItemType::ProcDerive => self.derives.insert(ItemEntry::new(new_url, name)),
+                ItemType::TraitAlias => self.trait_aliases.insert(ItemEntry::new(new_url, name)),
                 _ => true,
             };
         }
@@ -1900,6 +1930,7 @@ impl fmt::Display for AllTypes {
         print_entries(f, &self.derives, "Derive Macros", "derives")?;
         print_entries(f, &self.functions, "Functions", "functions")?;
         print_entries(f, &self.typedefs, "Typedefs", "typedefs")?;
+        print_entries(f, &self.trait_aliases, "Trait Aliases", "trait-aliases")?;
         print_entries(f, &self.existentials, "Existentials", "existentials")?;
         print_entries(f, &self.statics, "Statics", "statics")?;
         print_entries(f, &self.constants, "Constants", "constants")
@@ -2066,10 +2097,7 @@ impl Context {
         let mut themes = self.shared.themes.clone();
         let sidebar = "<p class='location'>Settings</p><div class='sidebar-elems'></div>";
         themes.push(PathBuf::from("settings.css"));
-        let mut layout = self.shared.layout.clone();
-        layout.krate = String::new();
-        layout.logo = String::new();
-        layout.favicon = String::new();
+        let layout = self.shared.layout.clone();
         try_err!(layout::render(&mut w, &layout,
                                 &page, &sidebar, &settings,
                                 self.shared.css_file_extension.is_some(),
@@ -2223,17 +2251,18 @@ impl Context {
                 if !self.render_redirect_pages {
                     all.append(full_path(self, &item), &item_type);
                 }
-                // Redirect from a sane URL using the namespace to Rustdoc's
-                // URL for the page.
-                let redir_name = format!("{}.{}.html", name, item_type.name_space());
-                let redir_dst = self.dst.join(redir_name);
-                if let Ok(redirect_out) = OpenOptions::new().create_new(true)
-                                                            .write(true)
-                                                            .open(&redir_dst) {
-                    let mut redirect_out = BufWriter::new(redirect_out);
-                    try_err!(layout::redirect(&mut redirect_out, file_name), &redir_dst);
+                if self.shared.generate_redirect_pages {
+                    // Redirect from a sane URL using the namespace to Rustdoc's
+                    // URL for the page.
+                    let redir_name = format!("{}.{}.html", name, item_type.name_space());
+                    let redir_dst = self.dst.join(redir_name);
+                    if let Ok(redirect_out) = OpenOptions::new().create_new(true)
+                                                                .write(true)
+                                                                .open(&redir_dst) {
+                        let mut redirect_out = BufWriter::new(redirect_out);
+                        try_err!(layout::redirect(&mut redirect_out, file_name), &redir_dst);
+                    }
                 }
-
                 // If the item is a macro, redirect from the old macro URL (with !)
                 // to the new one (without).
                 if item_type == ItemType::Macro {
@@ -2274,7 +2303,7 @@ impl Context {
 }
 
 impl<'a> Item<'a> {
-    /// Generate a url appropriate for an `href` attribute back to the source of
+    /// Generates a url appropriate for an `href` attribute back to the source of
     /// this item.
     ///
     /// The url generated, when clicked, will redirect the browser back to the
@@ -2400,6 +2429,7 @@ impl<'a> fmt::Display for Item<'a> {
             clean::ForeignTypeItem => write!(fmt, "Foreign Type ")?,
             clean::KeywordItem(..) => write!(fmt, "Keyword ")?,
             clean::ExistentialItem(..) => write!(fmt, "Existential Type ")?,
+            clean::TraitAliasItem(..) => write!(fmt, "Trait Alias ")?,
             _ => {
                 // We don't generate pages for any other type.
                 unreachable!();
@@ -2438,6 +2468,7 @@ impl<'a> fmt::Display for Item<'a> {
             clean::ForeignTypeItem => item_foreign_type(fmt, self.cx, self.item),
             clean::KeywordItem(ref k) => item_keyword(fmt, self.cx, self.item, k),
             clean::ExistentialItem(ref e, _) => item_existential(fmt, self.cx, self.item, e),
+            clean::TraitAliasItem(ref ta) => item_trait_alias(fmt, self.cx, self.item, ta),
             _ => {
                 // We don't generate pages for any other type.
                 unreachable!();
@@ -2448,7 +2479,7 @@ impl<'a> fmt::Display for Item<'a> {
 
 fn item_path(ty: ItemType, name: &str) -> String {
     match ty {
-        ItemType::Module => format!("{}/index.html", name),
+        ItemType::Module => format!("{}index.html", SlashChecker(name)),
         _ => format!("{}.{}.html", ty.css_class(), name),
     }
 }
@@ -2756,8 +2787,7 @@ fn item_module(w: &mut fmt::Formatter, cx: &Context,
                        <tr class='{stab}{add}module-item'>\
                            <td><a class=\"{class}\" href=\"{href}\" \
                                   title='{title}'>{name}</a>{unsafety_flag}</td>\
-                           <td class='docblock-short'>{stab_tags}{docs}\
-                           </td>\
+                           <td class='docblock-short'>{stab_tags}{docs}</td>\
                        </tr>",
                        name = *myitem.name.as_ref().unwrap(),
                        stab_tags = stability_tags(myitem),
@@ -2792,9 +2822,23 @@ fn item_module(w: &mut fmt::Formatter, cx: &Context,
 fn stability_tags(item: &clean::Item) -> String {
     let mut tags = String::new();
 
+    fn tag_html(class: &str, contents: &str) -> String {
+        format!(r#"<span class="stab {}">{}</span>"#, class, contents)
+    }
+
     // The trailing space after each tag is to space it properly against the rest of the docs.
     if item.deprecation().is_some() {
-        tags.push_str("[<div class='stab deprecated'>Deprecated</div>] ");
+        let mut message = "Deprecated";
+        if let Some(ref stab) = item.stability {
+            if let Some(ref depr) = stab.deprecation {
+                if let Some(ref since) = depr.since {
+                    if !stability::deprecation_in_effect(&since) {
+                        message = "Deprecation planned";
+                    }
+                }
+            }
+        }
+        tags += &tag_html("deprecated", message);
     }
 
     if let Some(stab) = item
@@ -2803,17 +2847,14 @@ fn stability_tags(item: &clean::Item) -> String {
         .filter(|s| s.level == stability::Unstable)
     {
         if stab.feature.as_ref().map(|s| &**s) == Some("rustc_private") {
-            tags.push_str("[<div class='stab internal'>Internal</div>] ");
+            tags += &tag_html("internal", "Internal");
         } else {
-            tags.push_str("[<div class='stab unstable'>Experimental</div>] ");
+            tags += &tag_html("unstable", "Experimental");
         }
     }
 
     if let Some(ref cfg) = item.attrs.cfg {
-        tags.push_str(&format!(
-            "[<div class='stab portability'>{}</div>] ",
-            cfg.render_short_html()
-        ));
+        tags += &tag_html("portability", &cfg.render_short_html());
     }
 
     tags
@@ -2825,16 +2866,23 @@ fn short_stability(item: &clean::Item, cx: &Context) -> Vec<String> {
     let mut stability = vec![];
     let error_codes = ErrorCodes::from(UnstableFeatures::from_environment().is_nightly_build());
 
-    if let Some(Deprecation { since, note }) = &item.deprecation() {
+    if let Some(Deprecation { note, since }) = &item.deprecation() {
+        // We display deprecation messages for #[deprecated] and #[rustc_deprecated]
+        // but only display the future-deprecation messages for #[rustc_deprecated].
         let mut message = if let Some(since) = since {
-            if stability::deprecation_in_effect(since) {
-                format!("Deprecated since {}", Escape(since))
-            } else {
-                format!("Deprecating in {}", Escape(since))
-            }
+            format!("Deprecated since {}", Escape(since))
         } else {
             String::from("Deprecated")
         };
+        if let Some(ref stab) = item.stability {
+            if let Some(ref depr) = stab.deprecation {
+                if let Some(ref since) = depr.since {
+                    if !stability::deprecation_in_effect(&since) {
+                        message = format!("Deprecating in {}", Escape(&since));
+                    }
+                }
+            }
+        }
 
         if let Some(note) = note {
             let mut ids = cx.id_map.borrow_mut();
@@ -2936,14 +2984,16 @@ fn item_static(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
 
 fn item_function(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
                  f: &clean::Function) -> fmt::Result {
-    let name_len = format!("{}{}{}{}{:#}fn {}{:#}",
-                           VisSpace(&it.visibility),
-                           ConstnessSpace(f.header.constness),
-                           UnsafetySpace(f.header.unsafety),
-                           AsyncSpace(f.header.asyncness),
-                           AbiSpace(f.header.abi),
-                           it.name.as_ref().unwrap(),
-                           f.generics).len();
+    let header_len = format!(
+        "{}{}{}{}{:#}fn {}{:#}",
+        VisSpace(&it.visibility),
+        ConstnessSpace(f.header.constness),
+        UnsafetySpace(f.header.unsafety),
+        AsyncSpace(f.header.asyncness),
+        AbiSpace(f.header.abi),
+        it.name.as_ref().unwrap(),
+        f.generics
+    ).len();
     write!(w, "{}<pre class='rust fn'>", render_spotlight_traits(it)?)?;
     render_attributes(w, it)?;
     write!(w,
@@ -2957,10 +3007,11 @@ fn item_function(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
            name = it.name.as_ref().unwrap(),
            generics = f.generics,
            where_clause = WhereClause { gens: &f.generics, indent: 0, end_newline: true },
-           decl = Method {
+           decl = Function {
               decl: &f.decl,
-              name_len,
+              header_len,
               indent: 0,
+              asyncness: f.header.asyncness,
            })?;
     document(w, cx, it)
 }
@@ -2994,23 +3045,17 @@ fn render_impls(cx: &Context, w: &mut fmt::Formatter,
     Ok(())
 }
 
-fn bounds(t_bounds: &[clean::GenericBound]) -> String {
+fn bounds(t_bounds: &[clean::GenericBound], trait_alias: bool) -> String {
     let mut bounds = String::new();
-    let mut bounds_plain = String::new();
     if !t_bounds.is_empty() {
-        if !bounds.is_empty() {
-            bounds.push(' ');
-            bounds_plain.push(' ');
+        if !trait_alias {
+            bounds.push_str(": ");
         }
-        bounds.push_str(": ");
-        bounds_plain.push_str(": ");
         for (i, p) in t_bounds.iter().enumerate() {
             if i > 0 {
                 bounds.push_str(" + ");
-                bounds_plain.push_str(" + ");
             }
             bounds.push_str(&(*p).to_string());
-            bounds_plain.push_str(&format!("{:#}", *p));
         }
     }
     bounds
@@ -3030,7 +3075,7 @@ fn item_trait(
     it: &clean::Item,
     t: &clean::Trait,
 ) -> fmt::Result {
-    let bounds = bounds(&t.bounds);
+    let bounds = bounds(&t.bounds, false);
     let types = t.items.iter().filter(|m| m.is_associated_type()).collect::<Vec<_>>();
     let consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
     let required = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
@@ -3379,16 +3424,18 @@ fn render_assoc_item(w: &mut fmt::Formatter,
                 href(did).map(|p| format!("{}#{}.{}", p.0, ty, name)).unwrap_or(anchor)
             }
         };
-        let mut head_len = format!("{}{}{}{}{:#}fn {}{:#}",
-                                   VisSpace(&meth.visibility),
-                                   ConstnessSpace(header.constness),
-                                   UnsafetySpace(header.unsafety),
-                                   AsyncSpace(header.asyncness),
-                                   AbiSpace(header.abi),
-                                   name,
-                                   *g).len();
+        let mut header_len = format!(
+            "{}{}{}{}{:#}fn {}{:#}",
+            VisSpace(&meth.visibility),
+            ConstnessSpace(header.constness),
+            UnsafetySpace(header.unsafety),
+            AsyncSpace(header.asyncness),
+            AbiSpace(header.abi),
+            name,
+            *g
+        ).len();
         let (indent, end_newline) = if parent == ItemType::Trait {
-            head_len += 4;
+            header_len += 4;
             (4, false)
         } else {
             (0, true)
@@ -3404,10 +3451,11 @@ fn render_assoc_item(w: &mut fmt::Formatter,
                href = href,
                name = name,
                generics = *g,
-               decl = Method {
+               decl = Function {
                    decl: d,
-                   name_len: head_len,
+                   header_len,
                    indent,
+                   asyncness: header.asyncness,
                },
                where_clause = WhereClause {
                    gens: g,
@@ -3477,10 +3525,6 @@ fn item_struct(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
                        ns_id = ns_id,
                        name = field.name.as_ref().unwrap(),
                        ty = ty)?;
-                if let Some(stability_class) = field.stability_class() {
-                    write!(w, "<span class='stab {stab}'></span>",
-                        stab = stability_class)?;
-                }
                 document(w, cx, field)?;
             }
         }
@@ -4264,7 +4308,26 @@ fn item_existential(
            it.name.as_ref().unwrap(),
            t.generics,
            where_clause = WhereClause { gens: &t.generics, indent: 0, end_newline: true },
-           bounds = bounds(&t.bounds))?;
+           bounds = bounds(&t.bounds, false))?;
+
+    document(w, cx, it)?;
+
+    // Render any items associated directly to this alias, as otherwise they
+    // won't be visible anywhere in the docs. It would be nice to also show
+    // associated items from the aliased type (see discussion in #32077), but
+    // we need #14072 to make sense of the generics.
+    render_assoc_items(w, cx, it, it.def_id, AssocItemRender::All)
+}
+
+fn item_trait_alias(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
+                    t: &clean::TraitAlias) -> fmt::Result {
+    write!(w, "<pre class='rust trait-alias'>")?;
+    render_attributes(w, it)?;
+    write!(w, "trait {}{}{} = {};</pre>",
+           it.name.as_ref().unwrap(),
+           t.generics,
+           WhereClause { gens: &t.generics, indent: 0, end_newline: true },
+           bounds(&t.bounds, true))?;
 
     document(w, cx, it)?;
 
@@ -4464,15 +4527,17 @@ fn sidebar_assoc_items(it: &clean::Item) -> String {
 
         {
             let used_links_bor = Rc::new(RefCell::new(&mut used_links));
-            let ret = v.iter()
-                       .filter(|i| i.inner_impl().trait_.is_none())
-                       .flat_map(move |i| get_methods(i.inner_impl(),
-                                                      false,
-                                                      &mut used_links_bor.borrow_mut()))
-                       .collect::<String>();
+            let mut ret = v.iter()
+                           .filter(|i| i.inner_impl().trait_.is_none())
+                           .flat_map(move |i| get_methods(i.inner_impl(),
+                                                          false,
+                                                          &mut used_links_bor.borrow_mut()))
+                           .collect::<Vec<_>>();
+            // We want links' order to be reproducible so we don't use unstable sort.
+            ret.sort();
             if !ret.is_empty() {
                 out.push_str(&format!("<a class=\"sidebar-title\" href=\"#methods\">Methods\
-                                       </a><div class=\"sidebar-links\">{}</div>", ret));
+                                       </a><div class=\"sidebar-links\">{}</div>", ret.join("")));
             }
         }
 
@@ -4496,40 +4561,47 @@ fn sidebar_assoc_items(it: &clean::Item) -> String {
                                                      impl_.inner_impl().trait_.as_ref().unwrap())),
                                               Escape(&format!("{:#}", target))));
                         out.push_str("</a>");
-                        let ret = impls.iter()
-                                       .filter(|i| i.inner_impl().trait_.is_none())
-                                       .flat_map(|i| get_methods(i.inner_impl(),
-                                                                 true,
-                                                                 &mut used_links))
-                                       .collect::<String>();
-                        out.push_str(&format!("<div class=\"sidebar-links\">{}</div>", ret));
+                        let mut ret = impls.iter()
+                                           .filter(|i| i.inner_impl().trait_.is_none())
+                                           .flat_map(|i| get_methods(i.inner_impl(),
+                                                                     true,
+                                                                     &mut used_links))
+                                           .collect::<Vec<_>>();
+                        // We want links' order to be reproducible so we don't use unstable sort.
+                        ret.sort();
+                        if !ret.is_empty() {
+                            out.push_str(&format!("<div class=\"sidebar-links\">{}</div>",
+                                                  ret.join("")));
+                        }
                     }
                 }
             }
             let format_impls = |impls: Vec<&Impl>| {
                 let mut links = FxHashSet::default();
 
-                impls.iter()
-                     .filter_map(|i| {
-                         let is_negative_impl = is_negative_impl(i.inner_impl());
-                         if let Some(ref i) = i.inner_impl().trait_ {
-                             let i_display = format!("{:#}", i);
-                             let out = Escape(&i_display);
-                             let encoded = small_url_encode(&format!("{:#}", i));
-                             let generated = format!("<a href=\"#impl-{}\">{}{}</a>",
-                                                     encoded,
-                                                     if is_negative_impl { "!" } else { "" },
-                                                     out);
-                             if links.insert(generated.clone()) {
-                                 Some(generated)
-                             } else {
-                                 None
-                             }
-                         } else {
-                             None
-                         }
-                     })
-                     .collect::<String>()
+                let mut ret = impls.iter()
+                    .filter_map(|i| {
+                        let is_negative_impl = is_negative_impl(i.inner_impl());
+                        if let Some(ref i) = i.inner_impl().trait_ {
+                            let i_display = format!("{:#}", i);
+                            let out = Escape(&i_display);
+                            let encoded = small_url_encode(&format!("{:#}", i));
+                            let generated = format!("<a href=\"#impl-{}\">{}{}</a>",
+                                                    encoded,
+                                                    if is_negative_impl { "!" } else { "" },
+                                                    out);
+                            if links.insert(generated.clone()) {
+                                Some(generated)
+                            } else {
+                                None
+                            }
+                        } else {
+                            None
+                        }
+                    })
+                    .collect::<Vec<String>>();
+                ret.sort();
+                ret.join("")
             };
 
             let (synthetic, concrete): (Vec<&Impl>, Vec<&Impl>) = v
@@ -4631,29 +4703,29 @@ fn sidebar_trait(fmt: &mut fmt::Formatter, it: &clean::Item,
                       }
                   })
                   .collect::<String>();
-    let required = t.items
-                    .iter()
-                    .filter_map(|m| {
-                        match m.name {
-                            Some(ref name) if m.is_ty_method() => {
-                                Some(format!("<a href=\"#tymethod.{name}\">{name}</a>",
-                                             name=name))
+    let mut required = t.items
+                        .iter()
+                        .filter_map(|m| {
+                            match m.name {
+                                Some(ref name) if m.is_ty_method() => {
+                                    Some(format!("<a href=\"#tymethod.{name}\">{name}</a>",
+                                                 name=name))
+                                }
+                                _ => None,
                             }
-                            _ => None,
-                        }
-                    })
-                    .collect::<String>();
-    let provided = t.items
-                    .iter()
-                    .filter_map(|m| {
-                        match m.name {
-                            Some(ref name) if m.is_method() => {
-                                Some(format!("<a href=\"#method.{name}\">{name}</a>", name=name))
+                        })
+                        .collect::<Vec<String>>();
+    let mut provided = t.items
+                        .iter()
+                        .filter_map(|m| {
+                            match m.name {
+                                Some(ref name) if m.is_method() => {
+                                    Some(format!("<a href=\"#method.{0}\">{0}</a>", name))
+                                }
+                                _ => None,
                             }
-                            _ => None,
-                        }
-                    })
-                    .collect::<String>();
+                        })
+                        .collect::<Vec<String>>();
 
     if !types.is_empty() {
         sidebar.push_str(&format!("<a class=\"sidebar-title\" href=\"#associated-types\">\
@@ -4666,38 +4738,41 @@ fn sidebar_trait(fmt: &mut fmt::Formatter, it: &clean::Item,
                                   consts));
     }
     if !required.is_empty() {
+        required.sort();
         sidebar.push_str(&format!("<a class=\"sidebar-title\" href=\"#required-methods\">\
                                    Required Methods</a><div class=\"sidebar-links\">{}</div>",
-                                  required));
+                                  required.join("")));
     }
     if !provided.is_empty() {
+        provided.sort();
         sidebar.push_str(&format!("<a class=\"sidebar-title\" href=\"#provided-methods\">\
                                    Provided Methods</a><div class=\"sidebar-links\">{}</div>",
-                                  provided));
+                                  provided.join("")));
     }
 
     let c = cache();
 
     if let Some(implementors) = c.implementors.get(&it.def_id) {
-        let res = implementors.iter()
-                              .filter(|i| i.inner_impl().for_.def_id()
-                              .map_or(false, |d| !c.paths.contains_key(&d)))
-                              .filter_map(|i| {
-                                  match extract_for_impl_name(&i.impl_item) {
-                                      Some((ref name, ref url)) => {
-                                          Some(format!("<a href=\"#impl-{}\">{}</a>",
-                                                      small_url_encode(url),
-                                                      Escape(name)))
+        let mut res = implementors.iter()
+                                  .filter(|i| i.inner_impl().for_.def_id()
+                                  .map_or(false, |d| !c.paths.contains_key(&d)))
+                                  .filter_map(|i| {
+                                      match extract_for_impl_name(&i.impl_item) {
+                                          Some((ref name, ref url)) => {
+                                              Some(format!("<a href=\"#impl-{}\">{}</a>",
+                                                          small_url_encode(url),
+                                                          Escape(name)))
+                                          }
+                                          _ => None,
                                       }
-                                      _ => None,
-                                  }
-                              })
-                              .collect::<String>();
+                                  })
+                                  .collect::<Vec<String>>();
         if !res.is_empty() {
+            res.sort();
             sidebar.push_str(&format!("<a class=\"sidebar-title\" href=\"#foreign-impls\">\
                                        Implementations on Foreign Types</a><div \
                                        class=\"sidebar-links\">{}</div>",
-                                      res));
+                                      res.join("")));
         }
     }
 
@@ -4816,6 +4891,7 @@ fn item_ty_to_strs(ty: &ItemType) -> (&'static str, &'static str) {
         ItemType::Existential     => ("existentials", "Existentials"),
         ItemType::ProcAttribute   => ("attributes", "Attribute Macros"),
         ItemType::ProcDerive      => ("derives", "Derive Macros"),
+        ItemType::TraitAlias      => ("trait-aliases", "Trait aliases"),
     }
 }
 
diff --git a/src/librustdoc/html/static/favicon.ico b/src/librustdoc/html/static/favicon.ico
new file mode 100644
index 0000000000000..b8ad23769ac8d
Binary files /dev/null and b/src/librustdoc/html/static/favicon.ico differ
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 82604cc7ad8bb..1849e53d937ad 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -68,7 +68,8 @@ if (!DOMTokenList.prototype.remove) {
                      "keyword",
                      "existential",
                      "attr",
-                     "derive"];
+                     "derive",
+                     "traitalias"];
 
     var search_input = document.getElementsByClassName("search-input")[0];
 
@@ -79,8 +80,6 @@ if (!DOMTokenList.prototype.remove) {
     // 2 for "In Return Types"
     var currentTab = 0;
 
-    var themesWidth = null;
-
     var titleBeforeSearch = document.title;
 
     function getPageId() {
@@ -150,8 +149,7 @@ if (!DOMTokenList.prototype.remove) {
     }
 
     function browserSupportsHistoryApi() {
-        return document.location.protocol != "file:" &&
-          window.history && typeof window.history.pushState === "function";
+        return window.history && typeof window.history.pushState === "function";
     }
 
     var main = document.getElementById("main");
@@ -241,7 +239,7 @@ if (!DOMTokenList.prototype.remove) {
         return String.fromCharCode(c);
     }
 
-    function displayHelp(display, ev) {
+    function displayHelp(display, ev, help) {
         if (display === true) {
             if (hasClass(help, "hidden")) {
                 ev.preventDefault();
@@ -259,7 +257,7 @@ if (!DOMTokenList.prototype.remove) {
         hideModal();
         var search = document.getElementById("search");
         if (hasClass(help, "hidden") === false) {
-            displayHelp(false, ev);
+            displayHelp(false, ev, help);
         } else if (hasClass(search, "hidden") === false) {
             ev.preventDefault();
             addClass(search, "hidden");
@@ -290,7 +288,7 @@ if (!DOMTokenList.prototype.remove) {
 
             case "s":
             case "S":
-                displayHelp(false, ev);
+                displayHelp(false, ev, help);
                 hideModal();
                 ev.preventDefault();
                 focusSearchBar();
@@ -305,7 +303,7 @@ if (!DOMTokenList.prototype.remove) {
             case "?":
                 if (ev.shiftKey) {
                     hideModal();
-                    displayHelp(true, ev);
+                    displayHelp(true, ev, help);
                 }
                 break;
             }
@@ -655,7 +653,7 @@ if (!DOMTokenList.prototype.remove) {
                                 return MAX_LEV_DISTANCE + 1;
                             }
                         }
-                        return lev_distance;//Math.ceil(total / done);
+                        return Math.ceil(total / done);
                     }
                 }
                 return MAX_LEV_DISTANCE + 1;
@@ -1198,7 +1196,7 @@ if (!DOMTokenList.prototype.remove) {
                 var actives = [[], [], []];
                 // "current" is used to know which tab we're looking into.
                 var current = 0;
-                onEachLazy(document.getElementsByClassName("search-results"), function(e) {
+                onEachLazy(document.getElementById("results").childNodes, function(e) {
                     onEachLazy(e.getElementsByClassName("highlighted"), function(e) {
                         actives[current].push(e);
                     });
@@ -1215,7 +1213,7 @@ if (!DOMTokenList.prototype.remove) {
                     removeClass(actives[currentTab][0], "highlighted");
                 } else if (e.which === 40) { // down
                     if (!actives[currentTab].length) {
-                        var results = document.getElementsByClassName("search-results");
+                        var results = document.getElementById("results").childNodes;
                         if (results.length > 0) {
                             var res = results[currentTab].getElementsByClassName("result");
                             if (res.length > 0) {
@@ -1599,7 +1597,7 @@ if (!DOMTokenList.prototype.remove) {
                 clearTimeout(searchTimeout);
                 if (search_input.value.length === 0) {
                     if (browserSupportsHistoryApi()) {
-                        history.replaceState("", "std - Rust", "?search=");
+                        history.replaceState("", window.currentCrate + " - Rust", "?search=");
                     }
                     if (hasClass(main, "content")) {
                         removeClass(main, "hidden");
@@ -1787,6 +1785,7 @@ if (!DOMTokenList.prototype.remove) {
         block("type", "Type Definitions");
         block("foreigntype", "Foreign Types");
         block("keyword", "Keywords");
+        block("traitalias", "Trait Aliases");
     }
 
     window.initSidebarItems = initSidebarItems;
@@ -1887,12 +1886,30 @@ if (!DOMTokenList.prototype.remove) {
             updateLocalStorage("rustdoc-collapse", "true");
             addClass(innerToggle, "will-expand");
             onEveryMatchingChild(innerToggle, "inner", function(e) {
-                e.innerHTML = labelForToggleButton(true);
+                var parent = e.parentNode;
+                var superParent = null;
+
+                if (parent) {
+                    superParent = parent.parentNode;
+                }
+                if (!parent || !superParent || superParent.id !== "main" ||
+                    hasClass(parent, "impl") === false) {
+                    e.innerHTML = labelForToggleButton(true);
+                }
             });
             innerToggle.title = "expand all docs";
             if (fromAutoCollapse !== true) {
                 onEachLazy(document.getElementsByClassName("collapse-toggle"), function(e) {
-                    collapseDocs(e, "hide", pageId);
+                    var parent = e.parentNode;
+                    var superParent = null;
+
+                    if (parent) {
+                        superParent = parent.parentNode;
+                    }
+                    if (!parent || !superParent || superParent.id !== "main" ||
+                        hasClass(parent, "impl") === false) {
+                        collapseDocs(e, "hide", pageId);
+                    }
                 });
             }
         }
@@ -1918,9 +1935,9 @@ if (!DOMTokenList.prototype.remove) {
             };
         }
 
-        function implHider(addOrRemove) {
+        function implHider(addOrRemove, fullHide) {
             return function(n) {
-                var is_method = hasClass(n, "method");
+                var is_method = hasClass(n, "method") || fullHide;
                 if (is_method || hasClass(n, "type")) {
                     if (is_method === true) {
                         if (addOrRemove) {
@@ -1974,7 +1991,7 @@ if (!DOMTokenList.prototype.remove) {
                 }
             }
         } else {
-            // we are collapsing the impl block
+            // we are collapsing the impl block(s).
 
             var parentElem = toggle.parentNode;
             relatedDoc = parentElem;
@@ -1989,7 +2006,7 @@ if (!DOMTokenList.prototype.remove) {
                 return;
             }
 
-            // Hide all functions, but not associated types/consts
+            // Hide all functions, but not associated types/consts.
 
             if (mode === "toggle") {
                 if (hasClass(relatedDoc, "fns-now-collapsed") ||
@@ -2000,16 +2017,17 @@ if (!DOMTokenList.prototype.remove) {
                 }
             }
 
+            var dontApplyBlockRule = toggle.parentNode.parentNode.id !== "main";
             if (action === "show") {
                 removeClass(relatedDoc, "fns-now-collapsed");
                 removeClass(docblock, "hidden-by-usual-hider");
-                onEachLazy(toggle.childNodes, adjustToggle(false));
-                onEachLazy(relatedDoc.childNodes, implHider(false));
+                onEachLazy(toggle.childNodes, adjustToggle(false, dontApplyBlockRule));
+                onEachLazy(relatedDoc.childNodes, implHider(false, dontApplyBlockRule));
             } else if (action === "hide") {
                 addClass(relatedDoc, "fns-now-collapsed");
                 addClass(docblock, "hidden-by-usual-hider");
-                onEachLazy(toggle.childNodes, adjustToggle(true));
-                onEachLazy(relatedDoc.childNodes, implHider(true));
+                onEachLazy(toggle.childNodes, adjustToggle(true, dontApplyBlockRule));
+                onEachLazy(relatedDoc.childNodes, implHider(true, dontApplyBlockRule));
             }
         }
     }
@@ -2414,7 +2432,7 @@ if (!DOMTokenList.prototype.remove) {
             // for vertical layout (column-oriented flex layout for divs caused
             // errors in mobile browsers).
             if (e.tagName === "H2" || e.tagName === "H3") {
-                let nextTagName = e.nextElementSibling.tagName;
+                var nextTagName = e.nextElementSibling.tagName;
                 if (nextTagName == "H2" || nextTagName == "H3") {
                     e.nextElementSibling.style.display = "flex";
                 } else {
diff --git a/src/librustdoc/html/static/rust-logo.png b/src/librustdoc/html/static/rust-logo.png
new file mode 100644
index 0000000000000..74b4bd695045e
Binary files /dev/null and b/src/librustdoc/html/static/rust-logo.png differ
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 8a8b7adcf7d4a..787f3c7f48004 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -391,10 +391,6 @@ h4 > code, h3 > code, .invisible > code {
 	display: block;
 }
 
-.in-band, code {
-	z-index: -5;
-}
-
 .invisible {
 	width: 100%;
 	display: inline-block;
@@ -428,7 +424,8 @@ h4 > code, h3 > code, .invisible > code {
 
 .docblock table {
 	margin: .5em 0;
-	width: 100%;
+	width: calc(100% - 2px);
+	border: 1px dashed;
 }
 
 .docblock table td {
@@ -661,7 +658,7 @@ a {
 	transition: border-color 300ms ease;
 	transition: border-radius 300ms ease-in-out;
 	transition: box-shadow 300ms ease-in-out;
-	width: 100%;
+	width: calc(100% - 32px);
 }
 
 #crate-search + .search-input {
@@ -771,11 +768,14 @@ body.blur > :not(#help) {
 }
 
 .module-item .stab {
-	display: inline;
-	border-width: 0;
-	padding: 0;
-	margin: 0;
-	background: inherit !important;
+	border-radius: 3px;
+	display: inline-block;
+	font-size: 80%;
+	line-height: 1.2;
+	margin-bottom: 0;
+	margin-right: .3em;
+	padding: 2px;
+	vertical-align: text-bottom;
 }
 
 .module-item.unstable {
@@ -1574,5 +1574,6 @@ div.name::before {
 }
 div.name.expand::before {
 	transform: rotate(90deg);
-	left: -14px;
+	left: -15px;
+	top: 2px;
 }
diff --git a/src/librustdoc/html/static/source-script.js b/src/librustdoc/html/static/source-script.js
index 0affe1c6812f5..509c628ce5a46 100644
--- a/src/librustdoc/html/static/source-script.js
+++ b/src/librustdoc/html/static/source-script.js
@@ -94,7 +94,7 @@ function createSidebarToggle() {
     inner1.style.position = "relative";
 
     var inner2 = document.createElement("div");
-    inner2.style.marginTop = "-2px";
+    inner2.style.paddingTop = "3px";
     if (getCurrentValue("rustdoc-source-sidebar-show") === "true") {
         inner2.innerText = "<";
     } else {
@@ -137,5 +137,3 @@ function createSourceSidebar() {
 
     main.insertBefore(sidebar, main.firstChild);
 }
-
-createSourceSidebar();
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index 1390be700634d..e756ab60ccc6d 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -68,26 +68,10 @@ pre {
 	border-bottom-color: #DDD;
 }
 
-.docblock table {
+.docblock table, .docblock table td, .docblock table th {
 	border-color: #ddd;
 }
 
-.docblock table td {
-	border-top-color: #ddd;
-	border-bottom-color: #ddd;
-}
-
-.docblock table th {
-	border-top-color: #ddd;
-	border-bottom-color: #ddd;
-}
-
-:target { background: #494a3d; }
-
-:target > .in-band {
-	background: #494a3d;
-}
-
 .content .method .where,
 .content .fn .where,
 .content .where.fmt-newline {
@@ -100,6 +84,7 @@ pre {
 }
 .content .highlighted a, .content .highlighted span { color: #eee !important; }
 .content .highlighted.trait { background-color: #013191; }
+.content .highlighted.traitalias { background-color: #013191; }
 .content .highlighted.mod,
 .content .highlighted.externcrate { background-color: #afc6e4; }
 .content .highlighted.mod { background-color: #803a1b; }
@@ -134,6 +119,7 @@ pre {
 .content span.externcrate,
 .content span.mod, .content a.mod, .block a.current.mod { color: #bda000; }
 .content span.trait, .content a.trait, .block a.current.trait { color: #b78cf2; }
+.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #b397da; }
 .content span.fn, .content a.fn, .block a.current.fn,
 .content span.method, .content a.method, .block a.current.method,
 .content span.tymethod, .content a.tymethod, .block a.current.tymethod,
@@ -194,15 +180,15 @@ a.test-arrow {
 	box-shadow: 1px 0 0 1px #000, 0 0 0 2px transparent;
 }
 
-.stab.unstable { background: #FFF5D6; border-color: #FFC600; color: #404040; }
-.stab.internal { background: #FFB9B3; border-color: #B71C1C; color: #404040; }
-.stab.deprecated { background: #F3DFFF; border-color: #7F0087;  color: #404040; }
-.stab.portability { background: #C4ECFF; border-color: #7BA5DB;  color: #404040; }
-
 .module-item .stab {
 	color: #ddd;
 }
 
+.stab.unstable {background: #FFF5D6; border-color: #FFC600; color: #2f2f2f; }
+.stab.internal { background: #FFB9B3; border-color: #B71C1C; color: #2f2f2f; }
+.stab.deprecated { background: #F3DFFF; border-color: #7F0087; color: #2f2f2f; }
+.stab.portability { background: #C4ECFF; border-color: #7BA5DB; color: #2f2f2f; }
+
 #help > div {
 	background: #4d4d4d;
 	border-color: #bfbfbf;
@@ -252,7 +238,7 @@ a.test-arrow:hover{
 	color: #999;
 }
 
-:target > code {
+:target > code, :target > .in-band {
 	background-color: #494a3d;
 }
 
@@ -416,10 +402,6 @@ kbd {
 	color: #ccc;
 }
 
-.impl-items code {
-	background-color: rgba(0, 0, 0, 0);
-}
-
 #sidebar-toggle {
 	background-color: #565656;
 }
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index 2b04dd2388d45..a294f6f2ff123 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -67,27 +67,11 @@ pre {
 }
 
 .docblock h1, .docblock h2, .docblock h3, .docblock h4, .docblock h5 {
-	border-bottom-color: #DDD;
-}
-
-.docblock table {
-	border-color: #ddd;
-}
-
-.docblock table td {
-	border-top-color: #ddd;
 	border-bottom-color: #ddd;
 }
 
-.docblock table th {
-	border-top-color: #ddd;
-	border-bottom-color: #ddd;
-}
-
-:target { background: #FDFFD3; }
-
-:target > .in-band {
-	background: #FDFFD3;
+.docblock table, .docblock table td, .docblock table th {
+	border-color: #ddd;
 }
 
 .content .method .where,
@@ -102,6 +86,7 @@ pre {
 }
 .content .highlighted a, .content .highlighted span { color: #000 !important; }
 .content .highlighted.trait { background-color: #c7b6ff; }
+.content .highlighted.traitalias { background-color: #c7b6ff; }
 .content .highlighted.mod,
 .content .highlighted.externcrate { background-color: #afc6e4; }
 .content .highlighted.enum { background-color: #b4d1b9; }
@@ -134,6 +119,7 @@ pre {
 .content span.externcrate,
 .content span.mod, .content a.mod, .block a.current.mod { color: #4d76ae; }
 .content span.trait, .content a.trait, .block a.current.trait { color: #7c5af3; }
+.content span.traitalias, .content a.traitalias, .block a.current.traitalias { color: #6841f1; }
 .content span.fn, .content a.fn, .block a.current.fn,
 .content span.method, .content a.method, .block a.current.method,
 .content span.tymethod, .content a.tymethod, .block a.current.tymethod,
@@ -195,15 +181,15 @@ a.test-arrow {
 	box-shadow: 1px 0 0 1px #e0e0e0, 0 0 0 2px transparent;
 }
 
+.module-item .stab {
+	color: #000;
+}
+
 .stab.unstable { background: #FFF5D6; border-color: #FFC600; }
 .stab.internal { background: #FFB9B3; border-color: #B71C1C; }
 .stab.deprecated { background: #F3DFFF; border-color: #7F0087; }
 .stab.portability { background: #C4ECFF; border-color: #7BA5DB; }
 
-.module-item .stab {
-	color: #000;
-}
-
 #help > div {
 	background: #e9e9e9;
 	border-color: #bfbfbf;
@@ -247,7 +233,7 @@ a.test-arrow:hover{
 	color: #999;
 }
 
-:target > code {
+:target > code, :target > .in-band {
 	background: #FDFFD3;
 }
 
@@ -411,10 +397,6 @@ kbd {
 	color: #999;
 }
 
-.impl-items code {
-	background-color: rgba(0, 0, 0, 0);
-}
-
 #sidebar-toggle {
 	background-color: #F1F1F1;
 }
diff --git a/src/librustdoc/html/static_files.rs b/src/librustdoc/html/static_files.rs
index f340590e5fe33..a1d8cfacc54ad 100644
--- a/src/librustdoc/html/static_files.rs
+++ b/src/librustdoc/html/static_files.rs
@@ -51,6 +51,11 @@ pub static LICENSE_APACHE: &'static [u8] = include_bytes!("static/LICENSE-APACHE
 /// The contents of `LICENSE-MIT.txt`, the text of the MIT License.
 pub static LICENSE_MIT: &'static [u8] = include_bytes!("static/LICENSE-MIT.txt");
 
+/// The contents of `rust-logo.png`, the default icon of the documentation.
+pub static RUST_LOGO: &'static [u8] = include_bytes!("static/rust-logo.png");
+/// The contents of `favicon.ico`, the default favicon of the documentation.
+pub static RUST_FAVICON: &'static [u8] = include_bytes!("static/favicon.ico");
+
 /// The built-in themes given to every documentation site.
 pub mod themes {
     /// The "light" theme, selected by default when no setting is available. Used as the basis for
diff --git a/src/librustdoc/html/toc.rs b/src/librustdoc/html/toc.rs
index a1a11bc81283d..b3da23060dcfe 100644
--- a/src/librustdoc/html/toc.rs
+++ b/src/librustdoc/html/toc.rs
@@ -58,7 +58,7 @@ impl TocBuilder {
     }
 
 
-    /// Convert into a true `Toc` struct.
+    /// Converts into a true `Toc` struct.
     pub fn into_toc(mut self) -> Toc {
         // we know all levels are >= 1.
         self.fold_until(0);
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 1b6d7e87192d6..43b366535159c 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -1,14 +1,12 @@
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/")]
 
+#![feature(bind_by_move_pattern_guards)]
 #![feature(rustc_private)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(nll)]
 #![feature(set_stdio)]
-#![feature(slice_sort_by_cached_key)]
 #![feature(test)]
 #![feature(vec_remove_item)]
 #![feature(ptr_offset_from)]
@@ -341,6 +339,17 @@ fn opts() -> Vec<RustcOptGroup> {
                       "disable-per-crate-search",
                       "disables generating the crate selector on the search box")
         }),
+        unstable("persist-doctests", |o| {
+             o.optopt("",
+                       "persist-doctests",
+                       "Directory to persist doctest executables into",
+                       "PATH")
+        }),
+        unstable("generate-redirect-pages", |o| {
+            o.optflag("",
+                      "generate-redirect-pages",
+                      "Generate extra pages to support legacy URLs and tool links")
+        }),
     ]
 }
 
diff --git a/src/librustdoc/markdown.rs b/src/librustdoc/markdown.rs
index da56194c27c2c..18729146749d8 100644
--- a/src/librustdoc/markdown.rs
+++ b/src/librustdoc/markdown.rs
@@ -127,7 +127,7 @@ pub fn render(input: PathBuf, options: RenderOptions, diag: &errors::Handler) ->
     }
 }
 
-/// Run any tests/code examples in the markdown file `input`.
+/// Runs any tests/code examples in the markdown file `input`.
 pub fn test(mut options: Options, diag: &errors::Handler) -> isize {
     let input_str = match load_string(&options.input, diag) {
         Ok(s) => s,
@@ -142,7 +142,7 @@ pub fn test(mut options: Options, diag: &errors::Handler) -> isize {
                                        options.libs, options.codegen_options, options.externs,
                                        true, opts, options.maybe_sysroot, None,
                                        Some(options.input),
-                                       options.linker, options.edition);
+                                       options.linker, options.edition, options.persist_doctests);
     collector.set_position(DUMMY_SP);
     let codes = ErrorCodes::from(UnstableFeatures::from_environment().is_nightly_build());
     let res = find_testable_code(&input_str, &mut collector, codes);
diff --git a/src/librustdoc/passes/check_code_block_syntax.rs b/src/librustdoc/passes/check_code_block_syntax.rs
new file mode 100644
index 0000000000000..8ccd55c17d060
--- /dev/null
+++ b/src/librustdoc/passes/check_code_block_syntax.rs
@@ -0,0 +1,109 @@
+use errors::Applicability;
+use syntax::parse::lexer::{TokenAndSpan, StringReader as Lexer};
+use syntax::parse::{ParseSess, token};
+use syntax::source_map::FilePathMapping;
+use syntax_pos::FileName;
+
+use clean;
+use core::DocContext;
+use fold::DocFolder;
+use html::markdown::{self, RustCodeBlock};
+use passes::Pass;
+
+pub const CHECK_CODE_BLOCK_SYNTAX: Pass =
+    Pass::early("check-code-block-syntax", check_code_block_syntax,
+                "validates syntax inside Rust code blocks");
+
+pub fn check_code_block_syntax(krate: clean::Crate, cx: &DocContext) -> clean::Crate {
+    SyntaxChecker { cx }.fold_crate(krate)
+}
+
+struct SyntaxChecker<'a, 'tcx: 'a, 'rcx: 'a> {
+    cx: &'a DocContext<'a, 'tcx, 'rcx>,
+}
+
+impl<'a, 'tcx, 'rcx> SyntaxChecker<'a, 'tcx, 'rcx> {
+    fn check_rust_syntax(&self, item: &clean::Item, dox: &str, code_block: RustCodeBlock) {
+        let sess = ParseSess::new(FilePathMapping::empty());
+        let source_file = sess.source_map().new_source_file(
+            FileName::Custom(String::from("doctest")),
+            dox[code_block.code].to_owned(),
+        );
+
+        let errors = Lexer::new_or_buffered_errs(&sess, source_file, None).and_then(|mut lexer| {
+            while let Ok(TokenAndSpan { tok, .. }) = lexer.try_next_token() {
+                if tok == token::Eof {
+                    break;
+                }
+            }
+
+            let errors = lexer.buffer_fatal_errors();
+
+            if !errors.is_empty() {
+                Err(errors)
+            } else {
+                Ok(())
+            }
+        });
+
+        if let Err(errors) = errors {
+            let mut diag = if let Some(sp) =
+                super::source_span_for_markdown_range(self.cx, &dox, &code_block.range, &item.attrs)
+            {
+                let mut diag = self
+                    .cx
+                    .sess()
+                    .struct_span_warn(sp, "could not parse code block as Rust code");
+
+                for mut err in errors {
+                    diag.note(&format!("error from rustc: {}", err.message()));
+                    err.cancel();
+                }
+
+                if code_block.syntax.is_none() && code_block.is_fenced {
+                    let sp = sp.from_inner_byte_pos(0, 3);
+                    diag.span_suggestion(
+                        sp,
+                        "mark blocks that do not contain Rust code as text",
+                        String::from("```text"),
+                        Applicability::MachineApplicable,
+                    );
+                }
+
+                diag
+            } else {
+                // We couldn't calculate the span of the markdown block that had the error, so our
+                // diagnostics are going to be a bit lacking.
+                let mut diag = self.cx.sess().struct_span_warn(
+                    super::span_of_attrs(&item.attrs),
+                    "doc comment contains an invalid Rust code block",
+                );
+
+                for mut err in errors {
+                    // Don't bother reporting the error, because we can't show where it happened.
+                    err.cancel();
+                }
+
+                if code_block.syntax.is_none() && code_block.is_fenced {
+                    diag.help("mark blocks that do not contain Rust code as text: ```text");
+                }
+
+                diag
+            };
+
+            diag.emit();
+        }
+    }
+}
+
+impl<'a, 'tcx, 'rcx> DocFolder for SyntaxChecker<'a, 'tcx, 'rcx> {
+    fn fold_item(&mut self, item: clean::Item) -> Option<clean::Item> {
+        if let Some(dox) = &item.attrs.collapsed_doc_value() {
+            for code_block in markdown::rust_code_blocks(&dox) {
+                self.check_rust_syntax(&item, &dox, code_block);
+            }
+        }
+
+        self.fold_item_recur(item)
+    }
+}
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index fdc1c0616187a..7f7fffbba100e 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -6,7 +6,7 @@ use syntax;
 use syntax::ast::{self, Ident, NodeId};
 use syntax::feature_gate::UnstableFeatures;
 use syntax::symbol::Symbol;
-use syntax_pos::{self, DUMMY_SP};
+use syntax_pos::DUMMY_SP;
 
 use std::ops::Range;
 
@@ -16,6 +16,7 @@ use html::markdown::markdown_links;
 
 use clean::*;
 use passes::{look_for_tests, Pass};
+use super::span_of_attrs;
 
 pub const COLLECT_INTRA_DOC_LINKS: Pass =
     Pass::early("collect-intra-doc-links", collect_intra_doc_links,
@@ -58,7 +59,7 @@ impl<'a, 'tcx, 'rcx> LinkCollector<'a, 'tcx, 'rcx> {
         }
     }
 
-    /// Resolve a given string as a path, along with whether or not it is
+    /// Resolves a given string as a path, along with whether or not it is
     /// in the value namespace. Also returns an optional URL fragment in the case
     /// of variants and methods.
     fn resolve(&self,
@@ -421,7 +422,7 @@ impl<'a, 'tcx, 'rcx> DocFolder for LinkCollector<'a, 'tcx, 'rcx> {
     }
 }
 
-/// Resolve a string as a macro.
+/// Resolves a string as a macro.
 fn macro_resolve(cx: &DocContext, path_str: &str) -> Option<Def> {
     use syntax::ext::base::{MacroKind, SyntaxExtension};
     let segment = ast::PathSegment::from_ident(Ident::from_str(path_str));
@@ -430,8 +431,12 @@ fn macro_resolve(cx: &DocContext, path_str: &str) -> Option<Def> {
     let parent_scope = resolver.dummy_parent_scope();
     if let Ok(def) = resolver.resolve_macro_to_def_inner(&path, MacroKind::Bang,
                                                          &parent_scope, false, false) {
-        if let SyntaxExtension::DeclMacro { .. } = *resolver.get_macro(def) {
-            return Some(def);
+        if let Def::Macro(_, MacroKind::ProcMacroStub) = def {
+            // skip proc-macro stubs, they'll cause `get_macro` to crash
+        } else {
+            if let SyntaxExtension::DeclMacro { .. } = *resolver.get_macro(def) {
+                return Some(def);
+            }
         }
     }
     if let Some(def) = resolver.all_macros.get(&Symbol::intern(path_str)) {
@@ -440,28 +445,11 @@ fn macro_resolve(cx: &DocContext, path_str: &str) -> Option<Def> {
     None
 }
 
-pub fn span_of_attrs(attrs: &Attributes) -> syntax_pos::Span {
-    if attrs.doc_strings.is_empty() {
-        return DUMMY_SP;
-    }
-    let start = attrs.doc_strings[0].span();
-    let end = attrs.doc_strings.last().expect("No doc strings provided").span();
-    start.to(end)
-}
-
 /// Reports a resolution failure diagnostic.
 ///
-/// Ideally we can report the diagnostic with the actual span in the source where the link failure
-/// occurred. However, there's a mismatch between the span in the source code and the span in the
-/// markdown, so we have to do a bit of work to figure out the correspondence.
-///
-/// It's not too hard to find the span for sugared doc comments (`///` and `/**`), because the
-/// source will match the markdown exactly, excluding the comment markers. However, it's much more
-/// difficult to calculate the spans for unsugared docs, because we have to deal with escaping and
-/// other source features. So, we attempt to find the exact source span of the resolution failure
-/// in sugared docs, but use the span of the documentation attributes themselves for unsugared
-/// docs. Because this span might be overly large, we display the markdown line containing the
-/// failure as a note.
+/// If we cannot find the exact source span of the resolution failure, we use the span of the
+/// documentation attributes themselves. This is a little heavy-handed, so we display the markdown
+/// line containing the failure as a note as well.
 fn resolution_failure(
     cx: &DocContext,
     attrs: &Attributes,
@@ -470,73 +458,18 @@ fn resolution_failure(
     link_range: Option<Range<usize>>,
 ) {
     let sp = span_of_attrs(attrs);
-    let msg = format!("`[{}]` cannot be resolved, ignoring it...", path_str);
-
-    let mut diag = if let Some(link_range) = link_range {
-        let src = cx.sess().source_map().span_to_snippet(sp);
-        let is_all_sugared_doc = attrs.doc_strings.iter().all(|frag| match frag {
-            DocFragment::SugaredDoc(..) => true,
-            _ => false,
-        });
 
-        if let (Ok(src), true) = (src, is_all_sugared_doc) {
-            // The number of markdown lines up to and including the resolution failure.
-            let num_lines = dox[..link_range.start].lines().count();
-
-            // We use `split_terminator('\n')` instead of `lines()` when counting bytes to ensure
-            // that DOS-style line endings do not cause the spans to be calculated incorrectly.
-            let mut src_lines = src.split_terminator('\n');
-            let mut md_lines = dox.split_terminator('\n').take(num_lines).peekable();
-
-            // The number of bytes from the start of the source span to the resolution failure that
-            // are *not* part of the markdown, like comment markers.
-            let mut extra_src_bytes = 0;
-
-            while let Some(md_line) = md_lines.next() {
-                loop {
-                    let source_line = src_lines
-                        .next()
-                        .expect("could not find markdown line in source");
-
-                    match source_line.find(md_line) {
-                        Some(offset) => {
-                            extra_src_bytes += if md_lines.peek().is_some() {
-                                source_line.len() - md_line.len()
-                            } else {
-                                offset
-                            };
-                            break;
-                        }
-                        None => {
-                            // Since this is a source line that doesn't include a markdown line,
-                            // we have to count the newline that we split from earlier.
-                            extra_src_bytes += source_line.len() + 1;
-                        }
-                    }
-                }
-            }
-
-            let sp = sp.from_inner_byte_pos(
-                link_range.start + extra_src_bytes,
-                link_range.end + extra_src_bytes,
-            );
-
-            let mut diag = cx.tcx.struct_span_lint_node(
-                lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
-                NodeId::from_u32(0),
-                sp,
-                &msg,
-            );
+    let mut diag = cx.tcx.struct_span_lint_node(
+        lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
+        NodeId::from_u32(0),
+        sp,
+        &format!("`[{}]` cannot be resolved, ignoring it...", path_str),
+    );
+    if let Some(link_range) = link_range {
+        if let Some(sp) = super::source_span_for_markdown_range(cx, dox, &link_range, attrs) {
+            diag.set_span(sp);
             diag.span_label(sp, "cannot be resolved, ignoring");
-            diag
         } else {
-            let mut diag = cx.tcx.struct_span_lint_node(
-                lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
-                NodeId::from_u32(0),
-                sp,
-                &msg,
-            );
-
             // blah blah blah\nblah\nblah [blah] blah blah\nblah blah
             //                       ^     ~~~~
             //                       |     link_range
@@ -553,13 +486,7 @@ fn resolution_failure(
                 before=link_range.start - last_new_line_offset,
                 found=link_range.len(),
             ));
-            diag
         }
-    } else {
-        cx.tcx.struct_span_lint_node(lint::builtin::INTRA_DOC_LINK_RESOLUTION_FAILURE,
-                                     NodeId::from_u32(0),
-                                     sp,
-                                     &msg)
     };
     diag.help("to escape `[` and `]` characters, just add '\\' before them like \
                `\\[` or `\\]`");
diff --git a/src/librustdoc/passes/mod.rs b/src/librustdoc/passes/mod.rs
index e897b9a7de58e..00622770adafc 100644
--- a/src/librustdoc/passes/mod.rs
+++ b/src/librustdoc/passes/mod.rs
@@ -8,6 +8,8 @@ use rustc::util::nodemap::DefIdSet;
 use std::mem;
 use std::fmt;
 use syntax::ast::NodeId;
+use syntax_pos::{DUMMY_SP, Span};
+use std::ops::Range;
 
 use clean::{self, GetDefId, Item};
 use core::{DocContext, DocAccessLevels};
@@ -16,8 +18,6 @@ use fold::StripItem;
 
 use html::markdown::{find_testable_code, ErrorCodes, LangString};
 
-use self::collect_intra_doc_links::span_of_attrs;
-
 mod collapse_docs;
 pub use self::collapse_docs::COLLAPSE_DOCS;
 
@@ -45,6 +45,9 @@ pub use self::private_items_doc_tests::CHECK_PRIVATE_ITEMS_DOC_TESTS;
 mod collect_trait_impls;
 pub use self::collect_trait_impls::COLLECT_TRAIT_IMPLS;
 
+mod check_code_block_syntax;
+pub use self::check_code_block_syntax::CHECK_CODE_BLOCK_SYNTAX;
+
 /// Represents a single pass.
 #[derive(Copy, Clone)]
 pub enum Pass {
@@ -135,6 +138,7 @@ pub const PASSES: &'static [Pass] = &[
     STRIP_PRIV_IMPORTS,
     PROPAGATE_DOC_CFG,
     COLLECT_INTRA_DOC_LINKS,
+    CHECK_CODE_BLOCK_SYNTAX,
     COLLECT_TRAIT_IMPLS,
 ];
 
@@ -145,6 +149,7 @@ pub const DEFAULT_PASSES: &'static [&'static str] = &[
     "strip-hidden",
     "strip-private",
     "collect-intra-doc-links",
+    "check-code-block-syntax",
     "collapse-docs",
     "unindent-comments",
     "propagate-doc-cfg",
@@ -156,6 +161,7 @@ pub const DEFAULT_PRIVATE_PASSES: &'static [&'static str] = &[
     "check-private-items-doc-tests",
     "strip-priv-imports",
     "collect-intra-doc-links",
+    "check-code-block-syntax",
     "collapse-docs",
     "unindent-comments",
     "propagate-doc-cfg",
@@ -218,6 +224,7 @@ impl<'a> fold::DocFolder for Stripper<'a> {
             | clean::ConstantItem(..)
             | clean::UnionItem(..)
             | clean::AssociatedConstItem(..)
+            | clean::TraitAliasItem(..)
             | clean::ForeignTypeItem => {
                 if i.def_id.is_local() {
                     if !self.access_levels.is_exported(i.def_id) {
@@ -396,3 +403,94 @@ pub fn look_for_tests<'a, 'tcx: 'a, 'rcx: 'a>(
         }
     }
 }
+
+/// Returns a span encompassing all the given attributes.
+crate fn span_of_attrs(attrs: &clean::Attributes) -> Span {
+    if attrs.doc_strings.is_empty() {
+        return DUMMY_SP;
+    }
+    let start = attrs.doc_strings[0].span();
+    let end = attrs.doc_strings.last().expect("No doc strings provided").span();
+    start.to(end)
+}
+
+/// Attempts to match a range of bytes from parsed markdown to a `Span` in the source code.
+///
+/// This method will return `None` if we cannot construct a span from the source map or if the
+/// attributes are not all sugared doc comments. It's difficult to calculate the correct span in
+/// that case due to escaping and other source features.
+crate fn source_span_for_markdown_range(
+    cx: &DocContext,
+    markdown: &str,
+    md_range: &Range<usize>,
+    attrs: &clean::Attributes,
+) -> Option<Span> {
+    let is_all_sugared_doc = attrs.doc_strings.iter().all(|frag| match frag {
+        clean::DocFragment::SugaredDoc(..) => true,
+        _ => false,
+    });
+
+    if !is_all_sugared_doc {
+        return None;
+    }
+
+    let snippet = cx
+        .sess()
+        .source_map()
+        .span_to_snippet(span_of_attrs(attrs))
+        .ok()?;
+
+    let starting_line = markdown[..md_range.start].lines().count() - 1;
+    let ending_line = markdown[..md_range.end].lines().count() - 1;
+
+    // We use `split_terminator('\n')` instead of `lines()` when counting bytes so that we only
+    // we can treat CRLF and LF line endings the same way.
+    let mut src_lines = snippet.split_terminator('\n');
+    let md_lines = markdown.split_terminator('\n');
+
+    // The number of bytes from the source span to the markdown span that are not part
+    // of the markdown, like comment markers.
+    let mut start_bytes = 0;
+    let mut end_bytes = 0;
+
+    'outer: for (line_no, md_line) in md_lines.enumerate() {
+        loop {
+            let source_line = src_lines.next().expect("could not find markdown in source");
+            match source_line.find(md_line) {
+                Some(offset) => {
+                    if line_no == starting_line {
+                        start_bytes += offset;
+
+                        if starting_line == ending_line {
+                            break 'outer;
+                        }
+                    } else if line_no == ending_line {
+                        end_bytes += offset;
+                        break 'outer;
+                    } else if line_no < starting_line {
+                        start_bytes += source_line.len() - md_line.len();
+                    } else {
+                        end_bytes += source_line.len() - md_line.len();
+                    }
+                    break;
+                }
+                None => {
+                    // Since this is a source line that doesn't include a markdown line,
+                    // we have to count the newline that we split from earlier.
+                    if line_no <= starting_line {
+                        start_bytes += source_line.len() + 1;
+                    } else {
+                        end_bytes += source_line.len() + 1;
+                    }
+                }
+            }
+        }
+    }
+
+    let sp = span_of_attrs(attrs).from_inner_byte_pos(
+        md_range.start + start_bytes,
+        md_range.end + start_bytes + end_bytes,
+    );
+
+    Some(sp)
+}
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index af47c7d5e8bfa..2195b90e1dc16 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -5,12 +5,11 @@ use rustc_lint;
 use rustc_driver::{self, driver, target_features, Compilation};
 use rustc_driver::driver::phase_2_configure_and_expand;
 use rustc_metadata::cstore::CStore;
-use rustc_metadata::dynamic_lib::DynamicLibrary;
 use rustc::hir;
 use rustc::hir::intravisit;
 use rustc::session::{self, CompileIncomplete, config};
 use rustc::session::config::{OutputType, OutputTypes, Externs, CodegenOptions};
-use rustc::session::search_paths::{SearchPath, PathKind};
+use rustc::session::search_paths::SearchPath;
 use syntax::ast;
 use syntax::source_map::SourceMap;
 use syntax::edition::Edition;
@@ -21,7 +20,6 @@ use tempfile::Builder as TempFileBuilder;
 use testing;
 
 use std::env;
-use std::ffi::OsString;
 use std::io::prelude::*;
 use std::io;
 use std::path::PathBuf;
@@ -120,7 +118,8 @@ pub fn run(mut options: Options) -> isize {
             Some(source_map),
             None,
             options.linker,
-            options.edition
+            options.edition,
+            options.persist_doctests,
         );
 
         {
@@ -184,7 +183,8 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
             cg: CodegenOptions, externs: Externs,
             should_panic: bool, no_run: bool, as_test_harness: bool,
             compile_fail: bool, mut error_codes: Vec<String>, opts: &TestOptions,
-            maybe_sysroot: Option<PathBuf>, linker: Option<PathBuf>, edition: Edition) {
+            maybe_sysroot: Option<PathBuf>, linker: Option<PathBuf>, edition: Edition,
+            persist_doctests: Option<PathBuf>) {
     // The test harness wants its own `main` and top-level functions, so
     // never wrap the test in `fn main() { ... }`.
     let (test, line_offset) = make_test(test, Some(cratename), as_test_harness, opts);
@@ -249,7 +249,21 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
     let old = io::set_panic(Some(box Sink(data.clone())));
     let _bomb = Bomb(data.clone(), old.unwrap_or(box io::stdout()));
 
-    let (libdir, outdir, compile_result) = driver::spawn_thread_pool(sessopts, |sessopts| {
+    enum DirState {
+        Temp(tempfile::TempDir),
+        Perm(PathBuf),
+    }
+
+    impl DirState {
+        fn path(&self) -> &std::path::Path {
+            match self {
+                DirState::Temp(t) => t.path(),
+                DirState::Perm(p) => p.as_path(),
+            }
+        }
+    }
+
+    let (outdir, compile_result) = driver::spawn_thread_pool(sessopts, |sessopts| {
         let source_map = Lrc::new(SourceMap::new(sessopts.file_path_mapping()));
         let emitter = errors::emitter::EmitterWriter::new(box Sink(data.clone()),
                                                         Some(source_map.clone()),
@@ -267,9 +281,27 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
         rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
 
         let outdir = Mutex::new(
-            TempFileBuilder::new().prefix("rustdoctest").tempdir().expect("rustdoc needs a tempdir")
+            if let Some(mut path) = persist_doctests {
+                path.push(format!("{}_{}",
+                    filename
+                        .to_string()
+                        .rsplit('/')
+                        .next()
+                        .unwrap()
+                        .replace(".", "_"),
+                        line)
+                );
+                std::fs::create_dir_all(&path)
+                    .expect("Couldn't create directory for doctest executables");
+
+                DirState::Perm(path)
+            } else {
+                DirState::Temp(TempFileBuilder::new()
+                                .prefix("rustdoctest")
+                                .tempdir()
+                                .expect("rustdoc needs a tempdir"))
+            }
         );
-        let libdir = sess.target_filesearch(PathKind::All).get_lib_path();
         let mut control = driver::CompileController::basic();
 
         let mut cfg = config::build_configuration(&sess, config::parse_cfgspecs(cfgs.clone()));
@@ -301,7 +333,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
             Err(_) | Ok(Err(CompileIncomplete::Errored(_))) => Err(())
         };
 
-        (libdir, outdir, compile_result)
+        (outdir, compile_result)
     });
 
     match (compile_result, compile_fail) {
@@ -327,21 +359,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
     if no_run { return }
 
     // Run the code!
-    //
-    // We're careful to prepend the *target* dylib search path to the child's
-    // environment to ensure that the target loads the right libraries at
-    // runtime. It would be a sad day if the *host* libraries were loaded as a
-    // mistake.
     let mut cmd = Command::new(&outdir.lock().unwrap().path().join("rust_out"));
-    let var = DynamicLibrary::envvar();
-    let newpath = {
-        let path = env::var_os(var).unwrap_or(OsString::new());
-        let mut path = env::split_paths(&path).collect::<Vec<_>>();
-        path.insert(0, libdir);
-        env::join_paths(path).unwrap()
-    };
-    cmd.env(var, &newpath);
-
     match cmd.output() {
         Err(e) => panic!("couldn't run the test: {}{}", e,
                         if e.kind() == io::ErrorKind::PermissionDenied {
@@ -499,13 +517,19 @@ pub fn make_test(s: &str,
         }
     }
 
-    if dont_insert_main || already_has_main {
+    // FIXME: This code cannot yet handle no_std test cases yet
+    if dont_insert_main || already_has_main || prog.contains("![no_std]") {
         prog.push_str(everything_else);
     } else {
-        prog.push_str("fn main() {\n");
+        let returns_result = everything_else.trim_end().ends_with("(())");
+        let (main_pre, main_post) = if returns_result {
+            ("fn main() { fn _inner() -> Result<(), impl core::fmt::Debug> {",
+             "}\n_inner().unwrap() }")
+        } else {
+            ("fn main() {\n", "\n}")
+        };
+        prog.extend([main_pre, everything_else, main_post].iter().cloned());
         line_offset += 1;
-        prog.push_str(everything_else);
-        prog.push_str("\n}");
     }
 
     debug!("final doctest:\n{}", prog);
@@ -629,13 +653,15 @@ pub struct Collector {
     filename: Option<PathBuf>,
     linker: Option<PathBuf>,
     edition: Edition,
+    persist_doctests: Option<PathBuf>,
 }
 
 impl Collector {
     pub fn new(cratename: String, cfgs: Vec<String>, libs: Vec<SearchPath>, cg: CodegenOptions,
                externs: Externs, use_headers: bool, opts: TestOptions,
                maybe_sysroot: Option<PathBuf>, source_map: Option<Lrc<SourceMap>>,
-               filename: Option<PathBuf>, linker: Option<PathBuf>, edition: Edition) -> Collector {
+               filename: Option<PathBuf>, linker: Option<PathBuf>, edition: Edition,
+               persist_doctests: Option<PathBuf>) -> Collector {
         Collector {
             tests: Vec::new(),
             names: Vec::new(),
@@ -652,6 +678,7 @@ impl Collector {
             filename,
             linker,
             edition,
+            persist_doctests,
         }
     }
 
@@ -695,6 +722,8 @@ impl Tester for Collector {
         let maybe_sysroot = self.maybe_sysroot.clone();
         let linker = self.linker.clone();
         let edition = config.edition.unwrap_or(self.edition);
+        let persist_doctests = self.persist_doctests.clone();
+
         debug!("Creating test {}: {}", name, test);
         self.tests.push(testing::TestDescAndFn {
             desc: testing::TestDesc {
@@ -727,7 +756,8 @@ impl Tester for Collector {
                                  &opts,
                                  maybe_sysroot,
                                  linker,
-                                 edition)
+                                 edition,
+                                 persist_doctests)
                     }))
                 } {
                     Ok(()) => (),
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index 953ab7c2565bf..c8a982702af51 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -259,7 +259,7 @@ impl<'a, 'tcx, 'rcx> RustdocVisitor<'a, 'tcx, 'rcx> {
     /// Cross-crate inlining occurs later on during crate cleaning
     /// and follows different rules.
     ///
-    /// Returns true if the target has been inlined.
+    /// Returns `true` if the target has been inlined.
     fn maybe_inline_local(&mut self,
                           id: ast::NodeId,
                           def: Def,
@@ -284,10 +284,11 @@ impl<'a, 'tcx, 'rcx> RustdocVisitor<'a, 'tcx, 'rcx> {
         debug!("maybe_inline_local def: {:?}", def);
 
         let tcx = self.cx.tcx;
-        if def == Def::Err {
+        let def_did = if let Some(did) = def.opt_def_id() {
+            did
+        } else {
             return false;
-        }
-        let def_did = def.def_id();
+        };
 
         let use_attrs = tcx.hir().attrs(id);
         // Don't inline `doc(hidden)` imports so they can be stripped at a later stage.
@@ -546,8 +547,19 @@ impl<'a, 'tcx, 'rcx> RustdocVisitor<'a, 'tcx, 'rcx> {
                 };
                 om.traits.push(t);
             },
-            hir::ItemKind::TraitAlias(..) => {
-                unimplemented!("trait objects are not yet implemented")
+            hir::ItemKind::TraitAlias(ref gen, ref b) => {
+                let t = TraitAlias {
+                    name: ident.name,
+                    generics: gen.clone(),
+                    bounds: b.iter().cloned().collect(),
+                    id: item.id,
+                    attrs: item.attrs.clone(),
+                    whence: item.span,
+                    vis: item.vis.clone(),
+                    stab: self.stability(item.id),
+                    depr: self.deprecation(item.id),
+                };
+                om.trait_aliases.push(t);
             },
 
             hir::ItemKind::Impl(unsafety,
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
index 7413a917f0563..bd5cae861e93b 100644
--- a/src/librustdoc/visit_lib.rs
+++ b/src/librustdoc/visit_lib.rs
@@ -60,9 +60,11 @@ impl<'a, 'tcx, 'rcx> LibEmbargoVisitor<'a, 'tcx, 'rcx> {
         }
 
         for item in self.cx.tcx.item_children(def_id).iter() {
-            if self.cx.tcx.def_key(item.def.def_id()).parent.map_or(false, |d| d == def_id.index) ||
-                item.vis == Visibility::Public {
-                self.visit_item(item.def);
+            if let Some(def_id) = item.def.opt_def_id() {
+                if self.cx.tcx.def_key(def_id).parent.map_or(false, |d| d == def_id.index) ||
+                    item.vis == Visibility::Public {
+                    self.visit_item(item.def);
+                }
             }
         }
     }
diff --git a/src/libserialize/Cargo.toml b/src/libserialize/Cargo.toml
index 3e040818d3777..949af0e2b9746 100644
--- a/src/libserialize/Cargo.toml
+++ b/src/libserialize/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "serialize"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "serialize"
diff --git a/src/libserialize/collection_impls.rs b/src/libserialize/collection_impls.rs
index f3afc3b53417c..c0a8fa9d0016d 100644
--- a/src/libserialize/collection_impls.rs
+++ b/src/libserialize/collection_impls.rs
@@ -2,7 +2,7 @@
 
 use std::hash::{Hash, BuildHasher};
 
-use {Decodable, Encodable, Decoder, Encoder};
+use crate::{Decodable, Encodable, Decoder, Encoder};
 use std::collections::{LinkedList, VecDeque, BTreeMap, BTreeSet, HashMap, HashSet};
 use std::rc::Rc;
 use std::sync::Arc;
diff --git a/src/libserialize/hex.rs b/src/libserialize/hex.rs
index 6127440a6d7d0..8a7927e42c9c3 100644
--- a/src/libserialize/hex.rs
+++ b/src/libserialize/hex.rs
@@ -60,7 +60,7 @@ pub enum FromHexError {
 }
 
 impl fmt::Display for FromHexError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             InvalidHexCharacter(ch, idx) =>
                 write!(f, "Invalid character '{}' at position {}", ch, idx),
@@ -80,7 +80,7 @@ impl error::Error for FromHexError {
 
 
 impl FromHex for str {
-    /// Convert any hexadecimal encoded string (literal, `@`, `&`, or `~`)
+    /// Converts any hexadecimal encoded string (literal, `@`, `&`, or `~`)
     /// to the byte values it encodes.
     ///
     /// You can use the `String::from_utf8` function to turn a
@@ -145,8 +145,8 @@ impl FromHex for str {
 #[cfg(test)]
 mod tests {
     extern crate test;
-    use self::test::Bencher;
-    use hex::{FromHex, ToHex};
+    use test::Bencher;
+    use crate::hex::{FromHex, ToHex};
 
     #[test]
     pub fn test_to_hex() {
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 362b4574ee24e..a4fd288451205 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -199,9 +199,8 @@ use std::ops::Index;
 use std::str::FromStr;
 use std::string;
 use std::{char, f64, fmt, str};
-use std;
 
-use Encodable;
+use crate::Encodable;
 
 /// Represents a json value
 #[derive(Clone, PartialEq, PartialOrd, Debug)]
@@ -221,8 +220,8 @@ pub type Object = BTreeMap<string::String, Json>;
 
 pub struct PrettyJson<'a> { inner: &'a Json }
 
-pub struct AsJson<'a, T: 'a> { inner: &'a T }
-pub struct AsPrettyJson<'a, T: 'a> { inner: &'a T, indent: Option<usize> }
+pub struct AsJson<'a, T> { inner: &'a T }
+pub struct AsPrettyJson<'a, T> { inner: &'a T, indent: Option<usize> }
 
 /// The errors that can arise while parsing a JSON stream.
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -295,18 +294,18 @@ pub fn error_str(error: ErrorCode) -> &'static str {
 }
 
 /// Shortcut function to decode a JSON `&str` into an object
-pub fn decode<T: ::Decodable>(s: &str) -> DecodeResult<T> {
+pub fn decode<T: crate::Decodable>(s: &str) -> DecodeResult<T> {
     let json = match from_str(s) {
         Ok(x) => x,
         Err(e) => return Err(ParseError(e))
     };
 
     let mut decoder = Decoder::new(json);
-    ::Decodable::decode(&mut decoder)
+    crate::Decodable::decode(&mut decoder)
 }
 
 /// Shortcut function to encode a `T` into a JSON `String`
-pub fn encode<T: ::Encodable>(object: &T) -> Result<string::String, EncoderError> {
+pub fn encode<T: crate::Encodable>(object: &T) -> Result<string::String, EncoderError> {
     let mut s = String::new();
     {
         let mut encoder = Encoder::new(&mut s);
@@ -316,7 +315,7 @@ pub fn encode<T: ::Encodable>(object: &T) -> Result<string::String, EncoderError
 }
 
 impl fmt::Display for ErrorCode {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         error_str(*self).fmt(f)
     }
 }
@@ -326,14 +325,14 @@ fn io_error_to_error(io: io::Error) -> ParserError {
 }
 
 impl fmt::Display for ParserError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // FIXME this should be a nicer error
         fmt::Debug::fmt(self, f)
     }
 }
 
 impl fmt::Display for DecoderError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // FIXME this should be a nicer error
         fmt::Debug::fmt(self, f)
     }
@@ -344,7 +343,7 @@ impl std::error::Error for DecoderError {
 }
 
 impl fmt::Display for EncoderError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         // FIXME this should be a nicer error
         fmt::Debug::fmt(self, f)
     }
@@ -477,7 +476,7 @@ macro_rules! emit_enquoted_if_mapkey {
     })
 }
 
-impl<'a> ::Encoder for Encoder<'a> {
+impl<'a> crate::Encoder for Encoder<'a> {
     type Error = EncoderError;
 
     fn emit_unit(&mut self) -> EncodeResult {
@@ -717,7 +716,7 @@ impl<'a> PrettyEncoder<'a> {
         }
     }
 
-    /// Set the number of spaces to indent for each level.
+    /// Sets the number of spaces to indent for each level.
     /// This is safe to set during encoding.
     pub fn set_indent(&mut self, indent: usize) {
         // self.indent very well could be 0 so we need to use checked division.
@@ -727,7 +726,7 @@ impl<'a> PrettyEncoder<'a> {
     }
 }
 
-impl<'a> ::Encoder for PrettyEncoder<'a> {
+impl<'a> crate::Encoder for PrettyEncoder<'a> {
     type Error = EncoderError;
 
     fn emit_unit(&mut self) -> EncodeResult {
@@ -997,7 +996,7 @@ impl<'a> ::Encoder for PrettyEncoder<'a> {
 }
 
 impl Encodable for Json {
-    fn encode<E: ::Encoder>(&self, e: &mut E) -> Result<(), E::Error> {
+    fn encode<E: crate::Encoder>(&self, e: &mut E) -> Result<(), E::Error> {
         match *self {
             Json::I64(v) => v.encode(e),
             Json::U64(v) => v.encode(e),
@@ -1011,22 +1010,22 @@ impl Encodable for Json {
     }
 }
 
-/// Create an `AsJson` wrapper which can be used to print a value as JSON
+/// Creates an `AsJson` wrapper which can be used to print a value as JSON
 /// on-the-fly via `write!`
-pub fn as_json<T>(t: &T) -> AsJson<T> {
+pub fn as_json<T>(t: &T) -> AsJson<'_, T> {
     AsJson { inner: t }
 }
 
-/// Create an `AsPrettyJson` wrapper which can be used to print a value as JSON
+/// Creates an `AsPrettyJson` wrapper which can be used to print a value as JSON
 /// on-the-fly via `write!`
-pub fn as_pretty_json<T>(t: &T) -> AsPrettyJson<T> {
+pub fn as_pretty_json<T>(t: &T) -> AsPrettyJson<'_, T> {
     AsPrettyJson { inner: t, indent: None }
 }
 
 impl Json {
     /// Borrow this json object as a pretty object to generate a pretty
     /// representation for it via `Display`.
-    pub fn pretty(&self) -> PrettyJson {
+    pub fn pretty(&self) -> PrettyJson<'_> {
         PrettyJson { inner: self }
     }
 
@@ -1040,7 +1039,7 @@ impl Json {
     }
 
     /// Attempts to get a nested Json Object for each key in `keys`.
-    /// If any key is found not to exist, find_path will return None.
+    /// If any key is found not to exist, `find_path` will return `None`.
     /// Otherwise, it will return the Json value associated with the final key.
     pub fn find_path<'a>(&'a self, keys: &[&str]) -> Option<&'a Json>{
         let mut target = self;
@@ -1052,7 +1051,7 @@ impl Json {
 
     /// If the Json value is an Object, performs a depth-first search until
     /// a value associated with the provided key is found. If no value is found
-    /// or the Json value is not an Object, returns None.
+    /// or the Json value is not an Object, returns `None`.
     pub fn search<'a>(&'a self, key: &str) -> Option<&'a Json> {
         match self {
             &Json::Object(ref map) => {
@@ -1073,13 +1072,13 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is an Object. Returns false otherwise.
+    /// Returns `true` if the Json value is an `Object`.
     pub fn is_object(&self) -> bool {
         self.as_object().is_some()
     }
 
-    /// If the Json value is an Object, returns the associated BTreeMap.
-    /// Returns None otherwise.
+    /// If the Json value is an `Object`, returns the associated `BTreeMap`;
+    /// returns `None` otherwise.
     pub fn as_object(&self) -> Option<&Object> {
         match *self {
             Json::Object(ref map) => Some(map),
@@ -1087,13 +1086,13 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is an Array. Returns false otherwise.
+    /// Returns `true` if the Json value is an `Array`.
     pub fn is_array(&self) -> bool {
         self.as_array().is_some()
     }
 
-    /// If the Json value is an Array, returns the associated vector.
-    /// Returns None otherwise.
+    /// If the Json value is an `Array`, returns the associated vector;
+    /// returns `None` otherwise.
     pub fn as_array(&self) -> Option<&Array> {
         match *self {
             Json::Array(ref array) => Some(&*array),
@@ -1101,13 +1100,13 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a String. Returns false otherwise.
+    /// Returns `true` if the Json value is a `String`.
     pub fn is_string(&self) -> bool {
         self.as_string().is_some()
     }
 
-    /// If the Json value is a String, returns the associated str.
-    /// Returns None otherwise.
+    /// If the Json value is a `String`, returns the associated `str`;
+    /// returns `None` otherwise.
     pub fn as_string(&self) -> Option<&str> {
         match *self {
             Json::String(ref s) => Some(&s[..]),
@@ -1115,7 +1114,7 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a Number. Returns false otherwise.
+    /// Returns `true` if the Json value is a `Number`.
     pub fn is_number(&self) -> bool {
         match *self {
             Json::I64(_) | Json::U64(_) | Json::F64(_) => true,
@@ -1123,7 +1122,7 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a i64. Returns false otherwise.
+    /// Returns `true` if the Json value is a `i64`.
     pub fn is_i64(&self) -> bool {
         match *self {
             Json::I64(_) => true,
@@ -1131,7 +1130,7 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a u64. Returns false otherwise.
+    /// Returns `true` if the Json value is a `u64`.
     pub fn is_u64(&self) -> bool {
         match *self {
             Json::U64(_) => true,
@@ -1139,7 +1138,7 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a f64. Returns false otherwise.
+    /// Returns `true` if the Json value is a `f64`.
     pub fn is_f64(&self) -> bool {
         match *self {
             Json::F64(_) => true,
@@ -1147,8 +1146,8 @@ impl Json {
         }
     }
 
-    /// If the Json value is a number, return or cast it to a i64.
-    /// Returns None otherwise.
+    /// If the Json value is a number, returns or cast it to a `i64`;
+    /// returns `None` otherwise.
     pub fn as_i64(&self) -> Option<i64> {
         match *self {
             Json::I64(n) => Some(n),
@@ -1157,8 +1156,8 @@ impl Json {
         }
     }
 
-    /// If the Json value is a number, return or cast it to a u64.
-    /// Returns None otherwise.
+    /// If the Json value is a number, returns or cast it to a `u64`;
+    /// returns `None` otherwise.
     pub fn as_u64(&self) -> Option<u64> {
         match *self {
             Json::I64(n) => Some(n as u64),
@@ -1167,8 +1166,8 @@ impl Json {
         }
     }
 
-    /// If the Json value is a number, return or cast it to a f64.
-    /// Returns None otherwise.
+    /// If the Json value is a number, returns or cast it to a `f64`;
+    /// returns `None` otherwise.
     pub fn as_f64(&self) -> Option<f64> {
         match *self {
             Json::I64(n) => Some(n as f64),
@@ -1178,13 +1177,13 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a Boolean. Returns false otherwise.
+    /// Returns `true` if the Json value is a `Boolean`.
     pub fn is_boolean(&self) -> bool {
         self.as_boolean().is_some()
     }
 
-    /// If the Json value is a Boolean, returns the associated bool.
-    /// Returns None otherwise.
+    /// If the Json value is a `Boolean`, returns the associated `bool`;
+    /// returns `None` otherwise.
     pub fn as_boolean(&self) -> Option<bool> {
         match *self {
             Json::Boolean(b) => Some(b),
@@ -1192,13 +1191,13 @@ impl Json {
         }
     }
 
-    /// Returns true if the Json value is a Null. Returns false otherwise.
+    /// Returns `true` if the Json value is a `Null`.
     pub fn is_null(&self) -> bool {
         self.as_null().is_some()
     }
 
-    /// If the Json value is a Null, returns ().
-    /// Returns None otherwise.
+    /// If the Json value is a `Null`, returns `()`;
+    /// returns `None` otherwise.
     pub fn as_null(&self) -> Option<()> {
         match *self {
             Json::Null => Some(()),
@@ -1294,13 +1293,13 @@ impl Stack {
     /// Returns The number of elements in the Stack.
     pub fn len(&self) -> usize { self.stack.len() }
 
-    /// Returns true if the stack is empty.
+    /// Returns `true` if the stack is empty.
     pub fn is_empty(&self) -> bool { self.stack.is_empty() }
 
     /// Provides access to the StackElement at a given index.
     /// lower indices are at the bottom of the stack while higher indices are
     /// at the top.
-    pub fn get(&self, idx: usize) -> StackElement {
+    pub fn get(&self, idx: usize) -> StackElement<'_> {
         match self.stack[idx] {
             InternalIndex(i) => StackElement::Index(i),
             InternalKey(start, size) => {
@@ -1311,8 +1310,8 @@ impl Stack {
         }
     }
 
-    /// Compares this stack with an array of StackElements.
-    pub fn is_equal_to(&self, rhs: &[StackElement]) -> bool {
+    /// Compares this stack with an array of StackElement<'_>s.
+    pub fn is_equal_to(&self, rhs: &[StackElement<'_>]) -> bool {
         if self.stack.len() != rhs.len() { return false; }
         for (i, r) in rhs.iter().enumerate() {
             if self.get(i) != *r { return false; }
@@ -1320,9 +1319,9 @@ impl Stack {
         true
     }
 
-    /// Returns true if the bottom-most elements of this stack are the same as
+    /// Returns `true` if the bottom-most elements of this stack are the same as
     /// the ones passed as parameter.
-    pub fn starts_with(&self, rhs: &[StackElement]) -> bool {
+    pub fn starts_with(&self, rhs: &[StackElement<'_>]) -> bool {
         if self.stack.len() < rhs.len() { return false; }
         for (i, r) in rhs.iter().enumerate() {
             if self.get(i) != *r { return false; }
@@ -1330,9 +1329,9 @@ impl Stack {
         true
     }
 
-    /// Returns true if the top-most elements of this stack are the same as
+    /// Returns `true` if the top-most elements of this stack are the same as
     /// the ones passed as parameter.
-    pub fn ends_with(&self, rhs: &[StackElement]) -> bool {
+    pub fn ends_with(&self, rhs: &[StackElement<'_>]) -> bool {
         if self.stack.len() < rhs.len() { return false; }
         let offset = self.stack.len() - rhs.len();
         for (i, r) in rhs.iter().enumerate() {
@@ -1342,7 +1341,7 @@ impl Stack {
     }
 
     /// Returns the top-most element (if any).
-    pub fn top(&self) -> Option<StackElement> {
+    pub fn top(&self) -> Option<StackElement<'_>> {
         match self.stack.last() {
             None => None,
             Some(&InternalIndex(i)) => Some(StackElement::Index(i)),
@@ -1955,7 +1954,7 @@ pub struct Builder<T> {
 }
 
 impl<T: Iterator<Item=char>> Builder<T> {
-    /// Create a JSON Builder.
+    /// Creates a JSON Builder.
     pub fn new(src: T) -> Builder<T> {
         Builder { parser: Parser::new(src), token: None, }
     }
@@ -2115,7 +2114,7 @@ macro_rules! read_primitive {
     }
 }
 
-impl ::Decoder for Decoder {
+impl crate::Decoder for Decoder {
     type Error = DecoderError;
 
     fn read_nil(&mut self) -> DecodeResult<()> {
@@ -2172,7 +2171,7 @@ impl ::Decoder for Decoder {
         Err(ExpectedError("single character string".to_owned(), s.to_string()))
     }
 
-    fn read_str(&mut self) -> DecodeResult<Cow<str>> {
+    fn read_str(&mut self) -> DecodeResult<Cow<'_, str>> {
         expect!(self.pop(), String).map(Cow::Owned)
     }
 
@@ -2518,7 +2517,7 @@ impl<'a, 'b> fmt::Write for FormatShim<'a, 'b> {
 
 impl fmt::Display for Json {
     /// Encodes a json value into a string
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut shim = FormatShim { inner: f };
         let mut encoder = Encoder::new(&mut shim);
         match self.encode(&mut encoder) {
@@ -2530,7 +2529,7 @@ impl fmt::Display for Json {
 
 impl<'a> fmt::Display for PrettyJson<'a> {
     /// Encodes a json value into a string
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut shim = FormatShim { inner: f };
         let mut encoder = PrettyEncoder::new(&mut shim);
         match self.inner.encode(&mut encoder) {
@@ -2542,7 +2541,7 @@ impl<'a> fmt::Display for PrettyJson<'a> {
 
 impl<'a, T: Encodable> fmt::Display for AsJson<'a, T> {
     /// Encodes a json value into a string
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut shim = FormatShim { inner: f };
         let mut encoder = Encoder::new(&mut shim);
         match self.inner.encode(&mut encoder) {
@@ -2553,7 +2552,7 @@ impl<'a, T: Encodable> fmt::Display for AsJson<'a, T> {
 }
 
 impl<'a, T> AsPrettyJson<'a, T> {
-    /// Set the indentation level for the emitted JSON
+    /// Sets the indentation level for the emitted JSON
     pub fn indent(mut self, indent: usize) -> AsPrettyJson<'a, T> {
         self.indent = Some(indent);
         self
@@ -2562,7 +2561,7 @@ impl<'a, T> AsPrettyJson<'a, T> {
 
 impl<'a, T: Encodable> fmt::Display for AsPrettyJson<'a, T> {
     /// Encodes a json value into a string
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let mut shim = FormatShim { inner: f };
         let mut encoder = PrettyEncoder::new(&mut shim);
         if let Some(n) = self.indent {
@@ -2584,1220 +2583,13 @@ impl FromStr for Json {
 
 #[cfg(test)]
 mod tests {
+    // Benchmarks and tests that require private items
+
     extern crate test;
-    use self::Animal::*;
-    use self::test::Bencher;
-    use {Encodable, Decodable};
-    use super::Json::*;
-    use super::ErrorCode::*;
-    use super::ParserError::*;
-    use super::DecoderError::*;
-    use super::JsonEvent::*;
-    use super::{Json, from_str, DecodeResult, DecoderError, JsonEvent, Parser,
-                StackElement, Stack, Decoder, Encoder, EncoderError};
-    use std::{i64, u64, f32, f64};
-    use std::io::prelude::*;
-    use std::collections::BTreeMap;
+    use test::Bencher;
+    use super::{from_str, Parser, StackElement, Stack};
     use std::string;
 
-    #[derive(RustcDecodable, Eq, PartialEq, Debug)]
-    struct OptionData {
-        opt: Option<usize>,
-    }
-
-    #[test]
-    fn test_decode_option_none() {
-        let s ="{}";
-        let obj: OptionData = super::decode(s).unwrap();
-        assert_eq!(obj, OptionData { opt: None });
-    }
-
-    #[test]
-    fn test_decode_option_some() {
-        let s = "{ \"opt\": 10 }";
-        let obj: OptionData = super::decode(s).unwrap();
-        assert_eq!(obj, OptionData { opt: Some(10) });
-    }
-
-    #[test]
-    fn test_decode_option_malformed() {
-        check_err::<OptionData>("{ \"opt\": [] }",
-                                ExpectedError("Number".to_string(), "[]".to_string()));
-        check_err::<OptionData>("{ \"opt\": false }",
-                                ExpectedError("Number".to_string(), "false".to_string()));
-    }
-
-    #[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
-    enum Animal {
-        Dog,
-        Frog(string::String, isize)
-    }
-
-    #[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
-    struct Inner {
-        a: (),
-        b: usize,
-        c: Vec<string::String>,
-    }
-
-    #[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
-    struct Outer {
-        inner: Vec<Inner>,
-    }
-
-    fn mk_object(items: &[(string::String, Json)]) -> Json {
-        let mut d = BTreeMap::new();
-
-        for item in items {
-            match *item {
-                (ref key, ref value) => { d.insert((*key).clone(), (*value).clone()); },
-            }
-        };
-
-        Object(d)
-    }
-
-    #[test]
-    fn test_from_str_trait() {
-        let s = "null";
-        assert!(s.parse::<Json>().unwrap() == s.parse().unwrap());
-    }
-
-    #[test]
-    fn test_write_null() {
-        assert_eq!(Null.to_string(), "null");
-        assert_eq!(Null.pretty().to_string(), "null");
-    }
-
-    #[test]
-    fn test_write_i64() {
-        assert_eq!(U64(0).to_string(), "0");
-        assert_eq!(U64(0).pretty().to_string(), "0");
-
-        assert_eq!(U64(1234).to_string(), "1234");
-        assert_eq!(U64(1234).pretty().to_string(), "1234");
-
-        assert_eq!(I64(-5678).to_string(), "-5678");
-        assert_eq!(I64(-5678).pretty().to_string(), "-5678");
-
-        assert_eq!(U64(7650007200025252000).to_string(), "7650007200025252000");
-        assert_eq!(U64(7650007200025252000).pretty().to_string(), "7650007200025252000");
-    }
-
-    #[test]
-    fn test_write_f64() {
-        assert_eq!(F64(3.0).to_string(), "3.0");
-        assert_eq!(F64(3.0).pretty().to_string(), "3.0");
-
-        assert_eq!(F64(3.1).to_string(), "3.1");
-        assert_eq!(F64(3.1).pretty().to_string(), "3.1");
-
-        assert_eq!(F64(-1.5).to_string(), "-1.5");
-        assert_eq!(F64(-1.5).pretty().to_string(), "-1.5");
-
-        assert_eq!(F64(0.5).to_string(), "0.5");
-        assert_eq!(F64(0.5).pretty().to_string(), "0.5");
-
-        assert_eq!(F64(f64::NAN).to_string(), "null");
-        assert_eq!(F64(f64::NAN).pretty().to_string(), "null");
-
-        assert_eq!(F64(f64::INFINITY).to_string(), "null");
-        assert_eq!(F64(f64::INFINITY).pretty().to_string(), "null");
-
-        assert_eq!(F64(f64::NEG_INFINITY).to_string(), "null");
-        assert_eq!(F64(f64::NEG_INFINITY).pretty().to_string(), "null");
-    }
-
-    #[test]
-    fn test_write_str() {
-        assert_eq!(String("".to_string()).to_string(), "\"\"");
-        assert_eq!(String("".to_string()).pretty().to_string(), "\"\"");
-
-        assert_eq!(String("homura".to_string()).to_string(), "\"homura\"");
-        assert_eq!(String("madoka".to_string()).pretty().to_string(), "\"madoka\"");
-    }
-
-    #[test]
-    fn test_write_bool() {
-        assert_eq!(Boolean(true).to_string(), "true");
-        assert_eq!(Boolean(true).pretty().to_string(), "true");
-
-        assert_eq!(Boolean(false).to_string(), "false");
-        assert_eq!(Boolean(false).pretty().to_string(), "false");
-    }
-
-    #[test]
-    fn test_write_array() {
-        assert_eq!(Array(vec![]).to_string(), "[]");
-        assert_eq!(Array(vec![]).pretty().to_string(), "[]");
-
-        assert_eq!(Array(vec![Boolean(true)]).to_string(), "[true]");
-        assert_eq!(
-            Array(vec![Boolean(true)]).pretty().to_string(),
-            "\
-            [\n  \
-                true\n\
-            ]"
-        );
-
-        let long_test_array = Array(vec![
-            Boolean(false),
-            Null,
-            Array(vec![String("foo\nbar".to_string()), F64(3.5)])]);
-
-        assert_eq!(long_test_array.to_string(),
-            "[false,null,[\"foo\\nbar\",3.5]]");
-        assert_eq!(
-            long_test_array.pretty().to_string(),
-            "\
-            [\n  \
-                false,\n  \
-                null,\n  \
-                [\n    \
-                    \"foo\\nbar\",\n    \
-                    3.5\n  \
-                ]\n\
-            ]"
-        );
-    }
-
-    #[test]
-    fn test_write_object() {
-        assert_eq!(mk_object(&[]).to_string(), "{}");
-        assert_eq!(mk_object(&[]).pretty().to_string(), "{}");
-
-        assert_eq!(
-            mk_object(&[
-                ("a".to_string(), Boolean(true))
-            ]).to_string(),
-            "{\"a\":true}"
-        );
-        assert_eq!(
-            mk_object(&[("a".to_string(), Boolean(true))]).pretty().to_string(),
-            "\
-            {\n  \
-                \"a\": true\n\
-            }"
-        );
-
-        let complex_obj = mk_object(&[
-                ("b".to_string(), Array(vec![
-                    mk_object(&[("c".to_string(), String("\x0c\r".to_string()))]),
-                    mk_object(&[("d".to_string(), String("".to_string()))])
-                ]))
-            ]);
-
-        assert_eq!(
-            complex_obj.to_string(),
-            "{\
-                \"b\":[\
-                    {\"c\":\"\\f\\r\"},\
-                    {\"d\":\"\"}\
-                ]\
-            }"
-        );
-        assert_eq!(
-            complex_obj.pretty().to_string(),
-            "\
-            {\n  \
-                \"b\": [\n    \
-                    {\n      \
-                        \"c\": \"\\f\\r\"\n    \
-                    },\n    \
-                    {\n      \
-                        \"d\": \"\"\n    \
-                    }\n  \
-                ]\n\
-            }"
-        );
-
-        let a = mk_object(&[
-            ("a".to_string(), Boolean(true)),
-            ("b".to_string(), Array(vec![
-                mk_object(&[("c".to_string(), String("\x0c\r".to_string()))]),
-                mk_object(&[("d".to_string(), String("".to_string()))])
-            ]))
-        ]);
-
-        // We can't compare the strings directly because the object fields be
-        // printed in a different order.
-        assert_eq!(a.clone(), a.to_string().parse().unwrap());
-        assert_eq!(a.clone(), a.pretty().to_string().parse().unwrap());
-    }
-
-    #[test]
-    fn test_write_enum() {
-        let animal = Dog;
-        assert_eq!(
-            super::as_json(&animal).to_string(),
-            "\"Dog\""
-        );
-        assert_eq!(
-            super::as_pretty_json(&animal).to_string(),
-            "\"Dog\""
-        );
-
-        let animal = Frog("Henry".to_string(), 349);
-        assert_eq!(
-            super::as_json(&animal).to_string(),
-            "{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}"
-        );
-        assert_eq!(
-            super::as_pretty_json(&animal).to_string(),
-            "{\n  \
-               \"variant\": \"Frog\",\n  \
-               \"fields\": [\n    \
-                 \"Henry\",\n    \
-                 349\n  \
-               ]\n\
-             }"
-        );
-    }
-
-    macro_rules! check_encoder_for_simple {
-        ($value:expr, $expected:expr) => ({
-            let s = super::as_json(&$value).to_string();
-            assert_eq!(s, $expected);
-
-            let s = super::as_pretty_json(&$value).to_string();
-            assert_eq!(s, $expected);
-        })
-    }
-
-    #[test]
-    fn test_write_some() {
-        check_encoder_for_simple!(Some("jodhpurs".to_string()), "\"jodhpurs\"");
-    }
-
-    #[test]
-    fn test_write_none() {
-        check_encoder_for_simple!(None::<string::String>, "null");
-    }
-
-    #[test]
-    fn test_write_char() {
-        check_encoder_for_simple!('a', "\"a\"");
-        check_encoder_for_simple!('\t', "\"\\t\"");
-        check_encoder_for_simple!('\u{0000}', "\"\\u0000\"");
-        check_encoder_for_simple!('\u{001b}', "\"\\u001b\"");
-        check_encoder_for_simple!('\u{007f}', "\"\\u007f\"");
-        check_encoder_for_simple!('\u{00a0}', "\"\u{00a0}\"");
-        check_encoder_for_simple!('\u{abcd}', "\"\u{abcd}\"");
-        check_encoder_for_simple!('\u{10ffff}', "\"\u{10ffff}\"");
-    }
-
-    #[test]
-    fn test_trailing_characters() {
-        assert_eq!(from_str("nulla"),  Err(SyntaxError(TrailingCharacters, 1, 5)));
-        assert_eq!(from_str("truea"),  Err(SyntaxError(TrailingCharacters, 1, 5)));
-        assert_eq!(from_str("falsea"), Err(SyntaxError(TrailingCharacters, 1, 6)));
-        assert_eq!(from_str("1a"),     Err(SyntaxError(TrailingCharacters, 1, 2)));
-        assert_eq!(from_str("[]a"),    Err(SyntaxError(TrailingCharacters, 1, 3)));
-        assert_eq!(from_str("{}a"),    Err(SyntaxError(TrailingCharacters, 1, 3)));
-    }
-
-    #[test]
-    fn test_read_identifiers() {
-        assert_eq!(from_str("n"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(from_str("nul"),  Err(SyntaxError(InvalidSyntax, 1, 4)));
-        assert_eq!(from_str("t"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(from_str("truz"), Err(SyntaxError(InvalidSyntax, 1, 4)));
-        assert_eq!(from_str("f"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(from_str("faz"),  Err(SyntaxError(InvalidSyntax, 1, 3)));
-
-        assert_eq!(from_str("null"), Ok(Null));
-        assert_eq!(from_str("true"), Ok(Boolean(true)));
-        assert_eq!(from_str("false"), Ok(Boolean(false)));
-        assert_eq!(from_str(" null "), Ok(Null));
-        assert_eq!(from_str(" true "), Ok(Boolean(true)));
-        assert_eq!(from_str(" false "), Ok(Boolean(false)));
-    }
-
-    #[test]
-    fn test_decode_identifiers() {
-        let v: () = super::decode("null").unwrap();
-        assert_eq!(v, ());
-
-        let v: bool = super::decode("true").unwrap();
-        assert_eq!(v, true);
-
-        let v: bool = super::decode("false").unwrap();
-        assert_eq!(v, false);
-    }
-
-    #[test]
-    fn test_read_number() {
-        assert_eq!(from_str("+"),   Err(SyntaxError(InvalidSyntax, 1, 1)));
-        assert_eq!(from_str("."),   Err(SyntaxError(InvalidSyntax, 1, 1)));
-        assert_eq!(from_str("NaN"), Err(SyntaxError(InvalidSyntax, 1, 1)));
-        assert_eq!(from_str("-"),   Err(SyntaxError(InvalidNumber, 1, 2)));
-        assert_eq!(from_str("00"),  Err(SyntaxError(InvalidNumber, 1, 2)));
-        assert_eq!(from_str("1."),  Err(SyntaxError(InvalidNumber, 1, 3)));
-        assert_eq!(from_str("1e"),  Err(SyntaxError(InvalidNumber, 1, 3)));
-        assert_eq!(from_str("1e+"), Err(SyntaxError(InvalidNumber, 1, 4)));
-
-        assert_eq!(from_str("18446744073709551616"), Err(SyntaxError(InvalidNumber, 1, 20)));
-        assert_eq!(from_str("-9223372036854775809"), Err(SyntaxError(InvalidNumber, 1, 21)));
-
-        assert_eq!(from_str("3"), Ok(U64(3)));
-        assert_eq!(from_str("3.1"), Ok(F64(3.1)));
-        assert_eq!(from_str("-1.2"), Ok(F64(-1.2)));
-        assert_eq!(from_str("0.4"), Ok(F64(0.4)));
-        assert_eq!(from_str("0.4e5"), Ok(F64(0.4e5)));
-        assert_eq!(from_str("0.4e+15"), Ok(F64(0.4e15)));
-        assert_eq!(from_str("0.4e-01"), Ok(F64(0.4e-01)));
-        assert_eq!(from_str(" 3 "), Ok(U64(3)));
-
-        assert_eq!(from_str("-9223372036854775808"), Ok(I64(i64::MIN)));
-        assert_eq!(from_str("9223372036854775807"), Ok(U64(i64::MAX as u64)));
-        assert_eq!(from_str("18446744073709551615"), Ok(U64(u64::MAX)));
-    }
-
-    #[test]
-    fn test_decode_numbers() {
-        let v: f64 = super::decode("3").unwrap();
-        assert_eq!(v, 3.0);
-
-        let v: f64 = super::decode("3.1").unwrap();
-        assert_eq!(v, 3.1);
-
-        let v: f64 = super::decode("-1.2").unwrap();
-        assert_eq!(v, -1.2);
-
-        let v: f64 = super::decode("0.4").unwrap();
-        assert_eq!(v, 0.4);
-
-        let v: f64 = super::decode("0.4e5").unwrap();
-        assert_eq!(v, 0.4e5);
-
-        let v: f64 = super::decode("0.4e15").unwrap();
-        assert_eq!(v, 0.4e15);
-
-        let v: f64 = super::decode("0.4e-01").unwrap();
-        assert_eq!(v, 0.4e-01);
-
-        let v: u64 = super::decode("0").unwrap();
-        assert_eq!(v, 0);
-
-        let v: u64 = super::decode("18446744073709551615").unwrap();
-        assert_eq!(v, u64::MAX);
-
-        let v: i64 = super::decode("-9223372036854775808").unwrap();
-        assert_eq!(v, i64::MIN);
-
-        let v: i64 = super::decode("9223372036854775807").unwrap();
-        assert_eq!(v, i64::MAX);
-
-        let res: DecodeResult<i64> = super::decode("765.25");
-        assert_eq!(res, Err(ExpectedError("Integer".to_string(),
-                                          "765.25".to_string())));
-    }
-
-    #[test]
-    fn test_read_str() {
-        assert_eq!(from_str("\""),    Err(SyntaxError(EOFWhileParsingString, 1, 2)));
-        assert_eq!(from_str("\"lol"), Err(SyntaxError(EOFWhileParsingString, 1, 5)));
-
-        assert_eq!(from_str("\"\""), Ok(String("".to_string())));
-        assert_eq!(from_str("\"foo\""), Ok(String("foo".to_string())));
-        assert_eq!(from_str("\"\\\"\""), Ok(String("\"".to_string())));
-        assert_eq!(from_str("\"\\b\""), Ok(String("\x08".to_string())));
-        assert_eq!(from_str("\"\\n\""), Ok(String("\n".to_string())));
-        assert_eq!(from_str("\"\\r\""), Ok(String("\r".to_string())));
-        assert_eq!(from_str("\"\\t\""), Ok(String("\t".to_string())));
-        assert_eq!(from_str(" \"foo\" "), Ok(String("foo".to_string())));
-        assert_eq!(from_str("\"\\u12ab\""), Ok(String("\u{12ab}".to_string())));
-        assert_eq!(from_str("\"\\uAB12\""), Ok(String("\u{AB12}".to_string())));
-    }
-
-    #[test]
-    fn test_decode_str() {
-        let s = [("\"\"", ""),
-                 ("\"foo\"", "foo"),
-                 ("\"\\\"\"", "\""),
-                 ("\"\\b\"", "\x08"),
-                 ("\"\\n\"", "\n"),
-                 ("\"\\r\"", "\r"),
-                 ("\"\\t\"", "\t"),
-                 ("\"\\u12ab\"", "\u{12ab}"),
-                 ("\"\\uAB12\"", "\u{AB12}")];
-
-        for &(i, o) in &s {
-            let v: string::String = super::decode(i).unwrap();
-            assert_eq!(v, o);
-        }
-    }
-
-    #[test]
-    fn test_read_array() {
-        assert_eq!(from_str("["),     Err(SyntaxError(EOFWhileParsingValue, 1, 2)));
-        assert_eq!(from_str("[1"),    Err(SyntaxError(EOFWhileParsingArray, 1, 3)));
-        assert_eq!(from_str("[1,"),   Err(SyntaxError(EOFWhileParsingValue, 1, 4)));
-        assert_eq!(from_str("[1,]"),  Err(SyntaxError(InvalidSyntax,        1, 4)));
-        assert_eq!(from_str("[6 7]"), Err(SyntaxError(InvalidSyntax,        1, 4)));
-
-        assert_eq!(from_str("[]"), Ok(Array(vec![])));
-        assert_eq!(from_str("[ ]"), Ok(Array(vec![])));
-        assert_eq!(from_str("[true]"), Ok(Array(vec![Boolean(true)])));
-        assert_eq!(from_str("[ false ]"), Ok(Array(vec![Boolean(false)])));
-        assert_eq!(from_str("[null]"), Ok(Array(vec![Null])));
-        assert_eq!(from_str("[3, 1]"),
-                     Ok(Array(vec![U64(3), U64(1)])));
-        assert_eq!(from_str("\n[3, 2]\n"),
-                     Ok(Array(vec![U64(3), U64(2)])));
-        assert_eq!(from_str("[2, [4, 1]]"),
-               Ok(Array(vec![U64(2), Array(vec![U64(4), U64(1)])])));
-    }
-
-    #[test]
-    fn test_decode_array() {
-        let v: Vec<()> = super::decode("[]").unwrap();
-        assert_eq!(v, []);
-
-        let v: Vec<()> = super::decode("[null]").unwrap();
-        assert_eq!(v, [()]);
-
-        let v: Vec<bool> = super::decode("[true]").unwrap();
-        assert_eq!(v, [true]);
-
-        let v: Vec<isize> = super::decode("[3, 1]").unwrap();
-        assert_eq!(v, [3, 1]);
-
-        let v: Vec<Vec<usize>> = super::decode("[[3], [1, 2]]").unwrap();
-        assert_eq!(v, [vec![3], vec![1, 2]]);
-    }
-
-    #[test]
-    fn test_decode_tuple() {
-        let t: (usize, usize, usize) = super::decode("[1, 2, 3]").unwrap();
-        assert_eq!(t, (1, 2, 3));
-
-        let t: (usize, string::String) = super::decode("[1, \"two\"]").unwrap();
-        assert_eq!(t, (1, "two".to_string()));
-    }
-
-    #[test]
-    fn test_decode_tuple_malformed_types() {
-        assert!(super::decode::<(usize, string::String)>("[1, 2]").is_err());
-    }
-
-    #[test]
-    fn test_decode_tuple_malformed_length() {
-        assert!(super::decode::<(usize, usize)>("[1, 2, 3]").is_err());
-    }
-
-    #[test]
-    fn test_read_object() {
-        assert_eq!(from_str("{"),       Err(SyntaxError(EOFWhileParsingObject, 1, 2)));
-        assert_eq!(from_str("{ "),      Err(SyntaxError(EOFWhileParsingObject, 1, 3)));
-        assert_eq!(from_str("{1"),      Err(SyntaxError(KeyMustBeAString,      1, 2)));
-        assert_eq!(from_str("{ \"a\""), Err(SyntaxError(EOFWhileParsingObject, 1, 6)));
-        assert_eq!(from_str("{\"a\""),  Err(SyntaxError(EOFWhileParsingObject, 1, 5)));
-        assert_eq!(from_str("{\"a\" "), Err(SyntaxError(EOFWhileParsingObject, 1, 6)));
-
-        assert_eq!(from_str("{\"a\" 1"),   Err(SyntaxError(ExpectedColon,         1, 6)));
-        assert_eq!(from_str("{\"a\":"),    Err(SyntaxError(EOFWhileParsingValue,  1, 6)));
-        assert_eq!(from_str("{\"a\":1"),   Err(SyntaxError(EOFWhileParsingObject, 1, 7)));
-        assert_eq!(from_str("{\"a\":1 1"), Err(SyntaxError(InvalidSyntax,         1, 8)));
-        assert_eq!(from_str("{\"a\":1,"),  Err(SyntaxError(EOFWhileParsingObject, 1, 8)));
-
-        assert_eq!(from_str("{}").unwrap(), mk_object(&[]));
-        assert_eq!(from_str("{\"a\": 3}").unwrap(),
-                  mk_object(&[("a".to_string(), U64(3))]));
-
-        assert_eq!(from_str(
-                      "{ \"a\": null, \"b\" : true }").unwrap(),
-                  mk_object(&[
-                      ("a".to_string(), Null),
-                      ("b".to_string(), Boolean(true))]));
-        assert_eq!(from_str("\n{ \"a\": null, \"b\" : true }\n").unwrap(),
-                  mk_object(&[
-                      ("a".to_string(), Null),
-                      ("b".to_string(), Boolean(true))]));
-        assert_eq!(from_str(
-                      "{\"a\" : 1.0 ,\"b\": [ true ]}").unwrap(),
-                  mk_object(&[
-                      ("a".to_string(), F64(1.0)),
-                      ("b".to_string(), Array(vec![Boolean(true)]))
-                  ]));
-        assert_eq!(from_str(
-                      "{\
-                          \"a\": 1.0, \
-                          \"b\": [\
-                              true,\
-                              \"foo\\nbar\", \
-                              { \"c\": {\"d\": null} } \
-                          ]\
-                      }").unwrap(),
-                  mk_object(&[
-                      ("a".to_string(), F64(1.0)),
-                      ("b".to_string(), Array(vec![
-                          Boolean(true),
-                          String("foo\nbar".to_string()),
-                          mk_object(&[
-                              ("c".to_string(), mk_object(&[("d".to_string(), Null)]))
-                          ])
-                      ]))
-                  ]));
-    }
-
-    #[test]
-    fn test_decode_struct() {
-        let s = "{
-            \"inner\": [
-                { \"a\": null, \"b\": 2, \"c\": [\"abc\", \"xyz\"] }
-            ]
-        }";
-
-        let v: Outer = super::decode(s).unwrap();
-        assert_eq!(
-            v,
-            Outer {
-                inner: vec![
-                    Inner { a: (), b: 2, c: vec!["abc".to_string(), "xyz".to_string()] }
-                ]
-            }
-        );
-    }
-
-    #[derive(RustcDecodable)]
-    struct FloatStruct {
-        f: f64,
-        a: Vec<f64>
-    }
-    #[test]
-    fn test_decode_struct_with_nan() {
-        let s = "{\"f\":null,\"a\":[null,123]}";
-        let obj: FloatStruct = super::decode(s).unwrap();
-        assert!(obj.f.is_nan());
-        assert!(obj.a[0].is_nan());
-        assert_eq!(obj.a[1], 123f64);
-    }
-
-    #[test]
-    fn test_decode_option() {
-        let value: Option<string::String> = super::decode("null").unwrap();
-        assert_eq!(value, None);
-
-        let value: Option<string::String> = super::decode("\"jodhpurs\"").unwrap();
-        assert_eq!(value, Some("jodhpurs".to_string()));
-    }
-
-    #[test]
-    fn test_decode_enum() {
-        let value: Animal = super::decode("\"Dog\"").unwrap();
-        assert_eq!(value, Dog);
-
-        let s = "{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}";
-        let value: Animal = super::decode(s).unwrap();
-        assert_eq!(value, Frog("Henry".to_string(), 349));
-    }
-
-    #[test]
-    fn test_decode_map() {
-        let s = "{\"a\": \"Dog\", \"b\": {\"variant\":\"Frog\",\
-                  \"fields\":[\"Henry\", 349]}}";
-        let mut map: BTreeMap<string::String, Animal> = super::decode(s).unwrap();
-
-        assert_eq!(map.remove(&"a".to_string()), Some(Dog));
-        assert_eq!(map.remove(&"b".to_string()), Some(Frog("Henry".to_string(), 349)));
-    }
-
-    #[test]
-    fn test_multiline_errors() {
-        assert_eq!(from_str("{\n  \"foo\":\n \"bar\""),
-            Err(SyntaxError(EOFWhileParsingObject, 3, 8)));
-    }
-
-    #[derive(RustcDecodable)]
-    #[allow(dead_code)]
-    struct DecodeStruct {
-        x: f64,
-        y: bool,
-        z: string::String,
-        w: Vec<DecodeStruct>
-    }
-    #[derive(RustcDecodable)]
-    enum DecodeEnum {
-        A(f64),
-        B(string::String)
-    }
-    fn check_err<T: Decodable>(to_parse: &'static str, expected: DecoderError) {
-        let res: DecodeResult<T> = match from_str(to_parse) {
-            Err(e) => Err(ParseError(e)),
-            Ok(json) => Decodable::decode(&mut Decoder::new(json))
-        };
-        match res {
-            Ok(_) => panic!("`{:?}` parsed & decoded ok, expecting error `{:?}`",
-                              to_parse, expected),
-            Err(ParseError(e)) => panic!("`{:?}` is not valid json: {:?}",
-                                           to_parse, e),
-            Err(e) => {
-                assert_eq!(e, expected);
-            }
-        }
-    }
-    #[test]
-    fn test_decode_errors_struct() {
-        check_err::<DecodeStruct>("[]", ExpectedError("Object".to_string(), "[]".to_string()));
-        check_err::<DecodeStruct>("{\"x\": true, \"y\": true, \"z\": \"\", \"w\": []}",
-                                  ExpectedError("Number".to_string(), "true".to_string()));
-        check_err::<DecodeStruct>("{\"x\": 1, \"y\": [], \"z\": \"\", \"w\": []}",
-                                  ExpectedError("Boolean".to_string(), "[]".to_string()));
-        check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": {}, \"w\": []}",
-                                  ExpectedError("String".to_string(), "{}".to_string()));
-        check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": \"\", \"w\": null}",
-                                  ExpectedError("Array".to_string(), "null".to_string()));
-        check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": \"\"}",
-                                  MissingFieldError("w".to_string()));
-    }
-    #[test]
-    fn test_decode_errors_enum() {
-        check_err::<DecodeEnum>("{}",
-                                MissingFieldError("variant".to_string()));
-        check_err::<DecodeEnum>("{\"variant\": 1}",
-                                ExpectedError("String".to_string(), "1".to_string()));
-        check_err::<DecodeEnum>("{\"variant\": \"A\"}",
-                                MissingFieldError("fields".to_string()));
-        check_err::<DecodeEnum>("{\"variant\": \"A\", \"fields\": null}",
-                                ExpectedError("Array".to_string(), "null".to_string()));
-        check_err::<DecodeEnum>("{\"variant\": \"C\", \"fields\": []}",
-                                UnknownVariantError("C".to_string()));
-    }
-
-    #[test]
-    fn test_find(){
-        let json_value = from_str("{\"dog\" : \"cat\"}").unwrap();
-        let found_str = json_value.find("dog");
-        assert!(found_str.unwrap().as_string().unwrap() == "cat");
-    }
-
-    #[test]
-    fn test_find_path(){
-        let json_value = from_str("{\"dog\":{\"cat\": {\"mouse\" : \"cheese\"}}}").unwrap();
-        let found_str = json_value.find_path(&["dog", "cat", "mouse"]);
-        assert!(found_str.unwrap().as_string().unwrap() == "cheese");
-    }
-
-    #[test]
-    fn test_search(){
-        let json_value = from_str("{\"dog\":{\"cat\": {\"mouse\" : \"cheese\"}}}").unwrap();
-        let found_str = json_value.search("mouse").and_then(|j| j.as_string());
-        assert!(found_str.unwrap() == "cheese");
-    }
-
-    #[test]
-    fn test_index(){
-        let json_value = from_str("{\"animals\":[\"dog\",\"cat\",\"mouse\"]}").unwrap();
-        let ref array = json_value["animals"];
-        assert_eq!(array[0].as_string().unwrap(), "dog");
-        assert_eq!(array[1].as_string().unwrap(), "cat");
-        assert_eq!(array[2].as_string().unwrap(), "mouse");
-    }
-
-    #[test]
-    fn test_is_object(){
-        let json_value = from_str("{}").unwrap();
-        assert!(json_value.is_object());
-    }
-
-    #[test]
-    fn test_as_object(){
-        let json_value = from_str("{}").unwrap();
-        let json_object = json_value.as_object();
-        assert!(json_object.is_some());
-    }
-
-    #[test]
-    fn test_is_array(){
-        let json_value = from_str("[1, 2, 3]").unwrap();
-        assert!(json_value.is_array());
-    }
-
-    #[test]
-    fn test_as_array(){
-        let json_value = from_str("[1, 2, 3]").unwrap();
-        let json_array = json_value.as_array();
-        let expected_length = 3;
-        assert!(json_array.is_some() && json_array.unwrap().len() == expected_length);
-    }
-
-    #[test]
-    fn test_is_string(){
-        let json_value = from_str("\"dog\"").unwrap();
-        assert!(json_value.is_string());
-    }
-
-    #[test]
-    fn test_as_string(){
-        let json_value = from_str("\"dog\"").unwrap();
-        let json_str = json_value.as_string();
-        let expected_str = "dog";
-        assert_eq!(json_str, Some(expected_str));
-    }
-
-    #[test]
-    fn test_is_number(){
-        let json_value = from_str("12").unwrap();
-        assert!(json_value.is_number());
-    }
-
-    #[test]
-    fn test_is_i64(){
-        let json_value = from_str("-12").unwrap();
-        assert!(json_value.is_i64());
-
-        let json_value = from_str("12").unwrap();
-        assert!(!json_value.is_i64());
-
-        let json_value = from_str("12.0").unwrap();
-        assert!(!json_value.is_i64());
-    }
-
-    #[test]
-    fn test_is_u64(){
-        let json_value = from_str("12").unwrap();
-        assert!(json_value.is_u64());
-
-        let json_value = from_str("-12").unwrap();
-        assert!(!json_value.is_u64());
-
-        let json_value = from_str("12.0").unwrap();
-        assert!(!json_value.is_u64());
-    }
-
-    #[test]
-    fn test_is_f64(){
-        let json_value = from_str("12").unwrap();
-        assert!(!json_value.is_f64());
-
-        let json_value = from_str("-12").unwrap();
-        assert!(!json_value.is_f64());
-
-        let json_value = from_str("12.0").unwrap();
-        assert!(json_value.is_f64());
-
-        let json_value = from_str("-12.0").unwrap();
-        assert!(json_value.is_f64());
-    }
-
-    #[test]
-    fn test_as_i64(){
-        let json_value = from_str("-12").unwrap();
-        let json_num = json_value.as_i64();
-        assert_eq!(json_num, Some(-12));
-    }
-
-    #[test]
-    fn test_as_u64(){
-        let json_value = from_str("12").unwrap();
-        let json_num = json_value.as_u64();
-        assert_eq!(json_num, Some(12));
-    }
-
-    #[test]
-    fn test_as_f64(){
-        let json_value = from_str("12.0").unwrap();
-        let json_num = json_value.as_f64();
-        assert_eq!(json_num, Some(12f64));
-    }
-
-    #[test]
-    fn test_is_boolean(){
-        let json_value = from_str("false").unwrap();
-        assert!(json_value.is_boolean());
-    }
-
-    #[test]
-    fn test_as_boolean(){
-        let json_value = from_str("false").unwrap();
-        let json_bool = json_value.as_boolean();
-        let expected_bool = false;
-        assert!(json_bool.is_some() && json_bool.unwrap() == expected_bool);
-    }
-
-    #[test]
-    fn test_is_null(){
-        let json_value = from_str("null").unwrap();
-        assert!(json_value.is_null());
-    }
-
-    #[test]
-    fn test_as_null(){
-        let json_value = from_str("null").unwrap();
-        let json_null = json_value.as_null();
-        let expected_null = ();
-        assert!(json_null.is_some() && json_null.unwrap() == expected_null);
-    }
-
-    #[test]
-    fn test_encode_hashmap_with_numeric_key() {
-        use std::str::from_utf8;
-        use std::collections::HashMap;
-        let mut hm: HashMap<usize, bool> = HashMap::new();
-        hm.insert(1, true);
-        let mut mem_buf = Vec::new();
-        write!(&mut mem_buf, "{}", super::as_pretty_json(&hm)).unwrap();
-        let json_str = from_utf8(&mem_buf[..]).unwrap();
-        match from_str(json_str) {
-            Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
-            _ => {} // it parsed and we are good to go
-        }
-    }
-
-    #[test]
-    fn test_prettyencode_hashmap_with_numeric_key() {
-        use std::str::from_utf8;
-        use std::collections::HashMap;
-        let mut hm: HashMap<usize, bool> = HashMap::new();
-        hm.insert(1, true);
-        let mut mem_buf = Vec::new();
-        write!(&mut mem_buf, "{}", super::as_pretty_json(&hm)).unwrap();
-        let json_str = from_utf8(&mem_buf[..]).unwrap();
-        match from_str(json_str) {
-            Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
-            _ => {} // it parsed and we are good to go
-        }
-    }
-
-    #[test]
-    fn test_prettyencoder_indent_level_param() {
-        use std::str::from_utf8;
-        use std::collections::BTreeMap;
-
-        let mut tree = BTreeMap::new();
-
-        tree.insert("hello".to_string(), String("guten tag".to_string()));
-        tree.insert("goodbye".to_string(), String("sayonara".to_string()));
-
-        let json = Array(
-            // The following layout below should look a lot like
-            // the pretty-printed JSON (indent * x)
-            vec!
-            ( // 0x
-                String("greetings".to_string()), // 1x
-                Object(tree), // 1x + 2x + 2x + 1x
-            ) // 0x
-            // End JSON array (7 lines)
-        );
-
-        // Helper function for counting indents
-        fn indents(source: &str) -> usize {
-            let trimmed = source.trim_start_matches(' ');
-            source.len() - trimmed.len()
-        }
-
-        // Test up to 4 spaces of indents (more?)
-        for i in 0..4 {
-            let mut writer = Vec::new();
-            write!(&mut writer, "{}",
-                   super::as_pretty_json(&json).indent(i)).unwrap();
-
-            let printed = from_utf8(&writer[..]).unwrap();
-
-            // Check for indents at each line
-            let lines: Vec<&str> = printed.lines().collect();
-            assert_eq!(lines.len(), 7); // JSON should be 7 lines
-
-            assert_eq!(indents(lines[0]), 0 * i); // [
-            assert_eq!(indents(lines[1]), 1 * i); //   "greetings",
-            assert_eq!(indents(lines[2]), 1 * i); //   {
-            assert_eq!(indents(lines[3]), 2 * i); //     "hello": "guten tag",
-            assert_eq!(indents(lines[4]), 2 * i); //     "goodbye": "sayonara"
-            assert_eq!(indents(lines[5]), 1 * i); //   },
-            assert_eq!(indents(lines[6]), 0 * i); // ]
-
-            // Finally, test that the pretty-printed JSON is valid
-            from_str(printed).ok().expect("Pretty-printed JSON is invalid!");
-        }
-    }
-
-    #[test]
-    fn test_hashmap_with_enum_key() {
-        use std::collections::HashMap;
-        use json;
-        #[derive(RustcEncodable, Eq, Hash, PartialEq, RustcDecodable, Debug)]
-        enum Enum {
-            Foo,
-            #[allow(dead_code)]
-            Bar,
-        }
-        let mut map = HashMap::new();
-        map.insert(Enum::Foo, 0);
-        let result = json::encode(&map).unwrap();
-        assert_eq!(&result[..], r#"{"Foo":0}"#);
-        let decoded: HashMap<Enum, _> = json::decode(&result).unwrap();
-        assert_eq!(map, decoded);
-    }
-
-    #[test]
-    fn test_hashmap_with_numeric_key_can_handle_double_quote_delimited_key() {
-        use std::collections::HashMap;
-        use Decodable;
-        let json_str = "{\"1\":true}";
-        let json_obj = match from_str(json_str) {
-            Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
-            Ok(o) => o
-        };
-        let mut decoder = Decoder::new(json_obj);
-        let _hm: HashMap<usize, bool> = Decodable::decode(&mut decoder).unwrap();
-    }
-
-    #[test]
-    fn test_hashmap_with_numeric_key_will_error_with_string_keys() {
-        use std::collections::HashMap;
-        use Decodable;
-        let json_str = "{\"a\":true}";
-        let json_obj = match from_str(json_str) {
-            Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
-            Ok(o) => o
-        };
-        let mut decoder = Decoder::new(json_obj);
-        let result: Result<HashMap<usize, bool>, DecoderError> = Decodable::decode(&mut decoder);
-        assert_eq!(result, Err(ExpectedError("Number".to_string(), "a".to_string())));
-    }
-
-    fn assert_stream_equal(src: &str,
-                           expected: Vec<(JsonEvent, Vec<StackElement>)>) {
-        let mut parser = Parser::new(src.chars());
-        let mut i = 0;
-        loop {
-            let evt = match parser.next() {
-                Some(e) => e,
-                None => { break; }
-            };
-            let (ref expected_evt, ref expected_stack) = expected[i];
-            if !parser.stack().is_equal_to(expected_stack) {
-                panic!("Parser stack is not equal to {:?}", expected_stack);
-            }
-            assert_eq!(&evt, expected_evt);
-            i+=1;
-        }
-    }
-    #[test]
-    fn test_streaming_parser() {
-        assert_stream_equal(
-            r#"{ "foo":"bar", "array" : [0, 1, 2, 3, 4, 5], "idents":[null,true,false]}"#,
-            vec![
-                (ObjectStart,             vec![]),
-                  (StringValue("bar".to_string()),   vec![StackElement::Key("foo")]),
-                  (ArrayStart,            vec![StackElement::Key("array")]),
-                    (U64Value(0),         vec![StackElement::Key("array"), StackElement::Index(0)]),
-                    (U64Value(1),         vec![StackElement::Key("array"), StackElement::Index(1)]),
-                    (U64Value(2),         vec![StackElement::Key("array"), StackElement::Index(2)]),
-                    (U64Value(3),         vec![StackElement::Key("array"), StackElement::Index(3)]),
-                    (U64Value(4),         vec![StackElement::Key("array"), StackElement::Index(4)]),
-                    (U64Value(5),         vec![StackElement::Key("array"), StackElement::Index(5)]),
-                  (ArrayEnd,              vec![StackElement::Key("array")]),
-                  (ArrayStart,            vec![StackElement::Key("idents")]),
-                    (NullValue,           vec![StackElement::Key("idents"),
-                                               StackElement::Index(0)]),
-                    (BooleanValue(true),  vec![StackElement::Key("idents"),
-                                               StackElement::Index(1)]),
-                    (BooleanValue(false), vec![StackElement::Key("idents"),
-                                               StackElement::Index(2)]),
-                  (ArrayEnd,              vec![StackElement::Key("idents")]),
-                (ObjectEnd,               vec![]),
-            ]
-        );
-    }
-    fn last_event(src: &str) -> JsonEvent {
-        let mut parser = Parser::new(src.chars());
-        let mut evt = NullValue;
-        loop {
-            evt = match parser.next() {
-                Some(e) => e,
-                None => return evt,
-            }
-        }
-    }
-
-    #[test]
-    fn test_read_object_streaming() {
-        assert_eq!(last_event("{ "),      Error(SyntaxError(EOFWhileParsingObject, 1, 3)));
-        assert_eq!(last_event("{1"),      Error(SyntaxError(KeyMustBeAString,      1, 2)));
-        assert_eq!(last_event("{ \"a\""), Error(SyntaxError(EOFWhileParsingObject, 1, 6)));
-        assert_eq!(last_event("{\"a\""),  Error(SyntaxError(EOFWhileParsingObject, 1, 5)));
-        assert_eq!(last_event("{\"a\" "), Error(SyntaxError(EOFWhileParsingObject, 1, 6)));
-
-        assert_eq!(last_event("{\"a\" 1"),   Error(SyntaxError(ExpectedColon,         1, 6)));
-        assert_eq!(last_event("{\"a\":"),    Error(SyntaxError(EOFWhileParsingValue,  1, 6)));
-        assert_eq!(last_event("{\"a\":1"),   Error(SyntaxError(EOFWhileParsingObject, 1, 7)));
-        assert_eq!(last_event("{\"a\":1 1"), Error(SyntaxError(InvalidSyntax,         1, 8)));
-        assert_eq!(last_event("{\"a\":1,"),  Error(SyntaxError(EOFWhileParsingObject, 1, 8)));
-        assert_eq!(last_event("{\"a\":1,}"), Error(SyntaxError(TrailingComma, 1, 8)));
-
-        assert_stream_equal(
-            "{}",
-            vec![(ObjectStart, vec![]), (ObjectEnd, vec![])]
-        );
-        assert_stream_equal(
-            "{\"a\": 3}",
-            vec![
-                (ObjectStart,        vec![]),
-                  (U64Value(3),      vec![StackElement::Key("a")]),
-                (ObjectEnd,          vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "{ \"a\": null, \"b\" : true }",
-            vec![
-                (ObjectStart,           vec![]),
-                  (NullValue,           vec![StackElement::Key("a")]),
-                  (BooleanValue(true),  vec![StackElement::Key("b")]),
-                (ObjectEnd,             vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "{\"a\" : 1.0 ,\"b\": [ true ]}",
-            vec![
-                (ObjectStart,           vec![]),
-                  (F64Value(1.0),       vec![StackElement::Key("a")]),
-                  (ArrayStart,          vec![StackElement::Key("b")]),
-                    (BooleanValue(true),vec![StackElement::Key("b"), StackElement::Index(0)]),
-                  (ArrayEnd,            vec![StackElement::Key("b")]),
-                (ObjectEnd,             vec![]),
-            ]
-        );
-        assert_stream_equal(
-            r#"{
-                "a": 1.0,
-                "b": [
-                    true,
-                    "foo\nbar",
-                    { "c": {"d": null} }
-                ]
-            }"#,
-            vec![
-                (ObjectStart,                   vec![]),
-                  (F64Value(1.0),               vec![StackElement::Key("a")]),
-                  (ArrayStart,                  vec![StackElement::Key("b")]),
-                    (BooleanValue(true),        vec![StackElement::Key("b"),
-                                                     StackElement::Index(0)]),
-                    (StringValue("foo\nbar".to_string()),  vec![StackElement::Key("b"),
-                                                                StackElement::Index(1)]),
-                    (ObjectStart,               vec![StackElement::Key("b"),
-                                                     StackElement::Index(2)]),
-                      (ObjectStart,             vec![StackElement::Key("b"),
-                                                     StackElement::Index(2),
-                                                     StackElement::Key("c")]),
-                        (NullValue,             vec![StackElement::Key("b"),
-                                                     StackElement::Index(2),
-                                                     StackElement::Key("c"),
-                                                     StackElement::Key("d")]),
-                      (ObjectEnd,               vec![StackElement::Key("b"),
-                                                     StackElement::Index(2),
-                                                     StackElement::Key("c")]),
-                    (ObjectEnd,                 vec![StackElement::Key("b"),
-                                                     StackElement::Index(2)]),
-                  (ArrayEnd,                    vec![StackElement::Key("b")]),
-                (ObjectEnd,                     vec![]),
-            ]
-        );
-    }
-    #[test]
-    fn test_read_array_streaming() {
-        assert_stream_equal(
-            "[]",
-            vec![
-                (ArrayStart, vec![]),
-                (ArrayEnd,   vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[ ]",
-            vec![
-                (ArrayStart, vec![]),
-                (ArrayEnd,   vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[true]",
-            vec![
-                (ArrayStart,             vec![]),
-                    (BooleanValue(true), vec![StackElement::Index(0)]),
-                (ArrayEnd,               vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[ false ]",
-            vec![
-                (ArrayStart,              vec![]),
-                    (BooleanValue(false), vec![StackElement::Index(0)]),
-                (ArrayEnd,                vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[null]",
-            vec![
-                (ArrayStart,    vec![]),
-                    (NullValue, vec![StackElement::Index(0)]),
-                (ArrayEnd,      vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[3, 1]",
-            vec![
-                (ArrayStart,      vec![]),
-                    (U64Value(3), vec![StackElement::Index(0)]),
-                    (U64Value(1), vec![StackElement::Index(1)]),
-                (ArrayEnd,        vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "\n[3, 2]\n",
-            vec![
-                (ArrayStart,      vec![]),
-                    (U64Value(3), vec![StackElement::Index(0)]),
-                    (U64Value(2), vec![StackElement::Index(1)]),
-                (ArrayEnd,        vec![]),
-            ]
-        );
-        assert_stream_equal(
-            "[2, [4, 1]]",
-            vec![
-                (ArrayStart,           vec![]),
-                    (U64Value(2),      vec![StackElement::Index(0)]),
-                    (ArrayStart,       vec![StackElement::Index(1)]),
-                        (U64Value(4),  vec![StackElement::Index(1), StackElement::Index(0)]),
-                        (U64Value(1),  vec![StackElement::Index(1), StackElement::Index(1)]),
-                    (ArrayEnd,         vec![StackElement::Index(1)]),
-                (ArrayEnd,             vec![]),
-            ]
-        );
-
-        assert_eq!(last_event("["), Error(SyntaxError(EOFWhileParsingValue, 1,  2)));
-
-        assert_eq!(from_str("["),     Err(SyntaxError(EOFWhileParsingValue, 1, 2)));
-        assert_eq!(from_str("[1"),    Err(SyntaxError(EOFWhileParsingArray, 1, 3)));
-        assert_eq!(from_str("[1,"),   Err(SyntaxError(EOFWhileParsingValue, 1, 4)));
-        assert_eq!(from_str("[1,]"),  Err(SyntaxError(InvalidSyntax,        1, 4)));
-        assert_eq!(from_str("[6 7]"), Err(SyntaxError(InvalidSyntax,        1, 4)));
-
-    }
-    #[test]
-    fn test_trailing_characters_streaming() {
-        assert_eq!(last_event("nulla"),  Error(SyntaxError(TrailingCharacters, 1, 5)));
-        assert_eq!(last_event("truea"),  Error(SyntaxError(TrailingCharacters, 1, 5)));
-        assert_eq!(last_event("falsea"), Error(SyntaxError(TrailingCharacters, 1, 6)));
-        assert_eq!(last_event("1a"),     Error(SyntaxError(TrailingCharacters, 1, 2)));
-        assert_eq!(last_event("[]a"),    Error(SyntaxError(TrailingCharacters, 1, 3)));
-        assert_eq!(last_event("{}a"),    Error(SyntaxError(TrailingCharacters, 1, 3)));
-    }
-    #[test]
-    fn test_read_identifiers_streaming() {
-        assert_eq!(Parser::new("null".chars()).next(), Some(NullValue));
-        assert_eq!(Parser::new("true".chars()).next(), Some(BooleanValue(true)));
-        assert_eq!(Parser::new("false".chars()).next(), Some(BooleanValue(false)));
-
-        assert_eq!(last_event("n"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(last_event("nul"),  Error(SyntaxError(InvalidSyntax, 1, 4)));
-        assert_eq!(last_event("t"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(last_event("truz"), Error(SyntaxError(InvalidSyntax, 1, 4)));
-        assert_eq!(last_event("f"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
-        assert_eq!(last_event("faz"),  Error(SyntaxError(InvalidSyntax, 1, 3)));
-    }
-
     #[test]
     fn test_stack() {
         let mut stack = Stack::new();
@@ -3862,76 +2654,6 @@ mod tests {
         assert!(stack.get(1) == StackElement::Key("foo"));
     }
 
-    #[test]
-    fn test_to_json() {
-        use std::collections::{HashMap,BTreeMap};
-        use super::ToJson;
-
-        let array2 = Array(vec![U64(1), U64(2)]);
-        let array3 = Array(vec![U64(1), U64(2), U64(3)]);
-        let object = {
-            let mut tree_map = BTreeMap::new();
-            tree_map.insert("a".to_string(), U64(1));
-            tree_map.insert("b".to_string(), U64(2));
-            Object(tree_map)
-        };
-
-        assert_eq!(array2.to_json(), array2);
-        assert_eq!(object.to_json(), object);
-        assert_eq!(3_isize.to_json(), I64(3));
-        assert_eq!(4_i8.to_json(), I64(4));
-        assert_eq!(5_i16.to_json(), I64(5));
-        assert_eq!(6_i32.to_json(), I64(6));
-        assert_eq!(7_i64.to_json(), I64(7));
-        assert_eq!(8_usize.to_json(), U64(8));
-        assert_eq!(9_u8.to_json(), U64(9));
-        assert_eq!(10_u16.to_json(), U64(10));
-        assert_eq!(11_u32.to_json(), U64(11));
-        assert_eq!(12_u64.to_json(), U64(12));
-        assert_eq!(13.0_f32.to_json(), F64(13.0_f64));
-        assert_eq!(14.0_f64.to_json(), F64(14.0_f64));
-        assert_eq!(().to_json(), Null);
-        assert_eq!(f32::INFINITY.to_json(), Null);
-        assert_eq!(f64::NAN.to_json(), Null);
-        assert_eq!(true.to_json(), Boolean(true));
-        assert_eq!(false.to_json(), Boolean(false));
-        assert_eq!("abc".to_json(), String("abc".to_string()));
-        assert_eq!("abc".to_string().to_json(), String("abc".to_string()));
-        assert_eq!((1_usize, 2_usize).to_json(), array2);
-        assert_eq!((1_usize, 2_usize, 3_usize).to_json(), array3);
-        assert_eq!([1_usize, 2_usize].to_json(), array2);
-        assert_eq!((&[1_usize, 2_usize, 3_usize]).to_json(), array3);
-        assert_eq!((vec![1_usize, 2_usize]).to_json(), array2);
-        assert_eq!(vec![1_usize, 2_usize, 3_usize].to_json(), array3);
-        let mut tree_map = BTreeMap::new();
-        tree_map.insert("a".to_string(), 1 as usize);
-        tree_map.insert("b".to_string(), 2);
-        assert_eq!(tree_map.to_json(), object);
-        let mut hash_map = HashMap::new();
-        hash_map.insert("a".to_string(), 1 as usize);
-        hash_map.insert("b".to_string(), 2);
-        assert_eq!(hash_map.to_json(), object);
-        assert_eq!(Some(15).to_json(), I64(15));
-        assert_eq!(Some(15 as usize).to_json(), U64(15));
-        assert_eq!(None::<isize>.to_json(), Null);
-    }
-
-    #[test]
-    fn test_encode_hashmap_with_arbitrary_key() {
-        use std::collections::HashMap;
-        #[derive(PartialEq, Eq, Hash, RustcEncodable)]
-        struct ArbitraryType(usize);
-        let mut hm: HashMap<ArbitraryType, bool> = HashMap::new();
-        hm.insert(ArbitraryType(1), true);
-        let mut mem_buf = string::String::new();
-        let mut encoder = Encoder::new(&mut mem_buf);
-        let result = hm.encode(&mut encoder);
-        match result.unwrap_err() {
-            EncoderError::BadHashmapKey => (),
-            _ => panic!("expected bad hash map key")
-        }
-    }
-
     #[bench]
     fn bench_streaming_small(b: &mut Bencher) {
         b.iter( || {
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index e8d185a9cc026..b8eeb4d2b34af 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -4,12 +4,12 @@
 Core encoding and decoding interfaces.
 */
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        test(attr(allow(unused_variables), deny(warnings))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(box_syntax)]
 #![feature(core_intrinsics)]
 #![feature(specialization)]
@@ -22,8 +22,6 @@ pub use self::serialize::{Decoder, Encoder, Decodable, Encodable};
 pub use self::serialize::{SpecializationError, SpecializedEncoder, SpecializedDecoder};
 pub use self::serialize::{UseSpecializedEncodable, UseSpecializedDecodable};
 
-extern crate smallvec;
-
 mod serialize;
 mod collection_impls;
 
@@ -32,7 +30,3 @@ pub mod json;
 
 pub mod opaque;
 pub mod leb128;
-
-mod rustc_serialize {
-    pub use serialize::*;
-}
diff --git a/src/libserialize/opaque.rs b/src/libserialize/opaque.rs
index b8d4f8a79f34b..a6a5c318079f1 100644
--- a/src/libserialize/opaque.rs
+++ b/src/libserialize/opaque.rs
@@ -1,6 +1,6 @@
-use leb128::{self, read_signed_leb128, write_signed_leb128};
+use crate::leb128::{self, read_signed_leb128, write_signed_leb128};
+use crate::serialize;
 use std::borrow::Cow;
-use serialize;
 
 // -----------------------------------------------------------------------------
 // Encoder
@@ -312,7 +312,7 @@ impl<'a> serialize::Decoder for Decoder<'a> {
     }
 
     #[inline]
-    fn read_str(&mut self) -> Result<Cow<str>, Self::Error> {
+    fn read_str(&mut self) -> Result<Cow<'_, str>, Self::Error> {
         let len = self.read_usize()?;
         let s = ::std::str::from_utf8(&self.data[self.position..self.position + len]).unwrap();
         self.position += len;
@@ -324,288 +324,3 @@ impl<'a> serialize::Decoder for Decoder<'a> {
         err.to_string()
     }
 }
-
-
-#[cfg(test)]
-mod tests {
-    use serialize::{Encodable, Decodable};
-    use std::fmt::Debug;
-    use super::{Encoder, Decoder};
-
-    #[derive(PartialEq, Clone, Debug, RustcEncodable, RustcDecodable)]
-    struct Struct {
-        a: (),
-        b: u8,
-        c: u16,
-        d: u32,
-        e: u64,
-        f: usize,
-
-        g: i8,
-        h: i16,
-        i: i32,
-        j: i64,
-        k: isize,
-
-        l: char,
-        m: String,
-        n: f32,
-        o: f64,
-        p: bool,
-        q: Option<u32>,
-    }
-
-
-    fn check_round_trip<T: Encodable + Decodable + PartialEq + Debug>(values: Vec<T>) {
-        let mut encoder = Encoder::new(Vec::new());
-
-        for value in &values {
-            Encodable::encode(&value, &mut encoder).unwrap();
-        }
-
-        let data = encoder.into_inner();
-        let mut decoder = Decoder::new(&data[..], 0);
-
-        for value in values {
-            let decoded = Decodable::decode(&mut decoder).unwrap();
-            assert_eq!(value, decoded);
-        }
-    }
-
-    #[test]
-    fn test_unit() {
-        check_round_trip(vec![(), (), (), ()]);
-    }
-
-    #[test]
-    fn test_u8() {
-        let mut vec = vec![];
-        for i in ::std::u8::MIN..::std::u8::MAX {
-            vec.push(i);
-        }
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_u16() {
-        for i in ::std::u16::MIN..::std::u16::MAX {
-            check_round_trip(vec![1, 2, 3, i, i, i]);
-        }
-    }
-
-    #[test]
-    fn test_u32() {
-        check_round_trip(vec![1, 2, 3, ::std::u32::MIN, 0, 1, ::std::u32::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_u64() {
-        check_round_trip(vec![1, 2, 3, ::std::u64::MIN, 0, 1, ::std::u64::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_usize() {
-        check_round_trip(vec![1, 2, 3, ::std::usize::MIN, 0, 1, ::std::usize::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_i8() {
-        let mut vec = vec![];
-        for i in ::std::i8::MIN..::std::i8::MAX {
-            vec.push(i);
-        }
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_i16() {
-        for i in ::std::i16::MIN..::std::i16::MAX {
-            check_round_trip(vec![-1, 2, -3, i, i, i, 2]);
-        }
-    }
-
-    #[test]
-    fn test_i32() {
-        check_round_trip(vec![-1, 2, -3, ::std::i32::MIN, 0, 1, ::std::i32::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_i64() {
-        check_round_trip(vec![-1, 2, -3, ::std::i64::MIN, 0, 1, ::std::i64::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_isize() {
-        check_round_trip(vec![-1, 2, -3, ::std::isize::MIN, 0, 1, ::std::isize::MAX, 2, 1]);
-    }
-
-    #[test]
-    fn test_bool() {
-        check_round_trip(vec![false, true, true, false, false]);
-    }
-
-    #[test]
-    fn test_f32() {
-        let mut vec = vec![];
-        for i in -100..100 {
-            vec.push((i as f32) / 3.0);
-        }
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_f64() {
-        let mut vec = vec![];
-        for i in -100..100 {
-            vec.push((i as f64) / 3.0);
-        }
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_char() {
-        let vec = vec!['a', 'b', 'c', 'd', 'A', 'X', ' ', '#', 'Ö', 'Ä', 'µ', '€'];
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_string() {
-        let vec = vec!["abcbuÖeiovÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
-                       "abcbuÖganeiovÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
-                       "abcbuÖganeiovÄnameÜavmpßvmea€µsbpapmaebn".to_string(),
-                       "abcbuÖganeiovÄnameÜavmpßvmeabpnvapeapmaebn".to_string(),
-                       "abcbuÖganeiÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
-                       "abcbuÖganeiovÄnameÜavmpßvmea€µsbpmaebn".to_string(),
-                       "abcbuÖganeiovÄnameÜavmpßvmea€µnvapeapmaebn".to_string()];
-
-        check_round_trip(vec);
-    }
-
-    #[test]
-    fn test_option() {
-        check_round_trip(vec![Some(-1i8)]);
-        check_round_trip(vec![Some(-2i16)]);
-        check_round_trip(vec![Some(-3i32)]);
-        check_round_trip(vec![Some(-4i64)]);
-        check_round_trip(vec![Some(-5isize)]);
-
-        let none_i8: Option<i8> = None;
-        check_round_trip(vec![none_i8]);
-
-        let none_i16: Option<i16> = None;
-        check_round_trip(vec![none_i16]);
-
-        let none_i32: Option<i32> = None;
-        check_round_trip(vec![none_i32]);
-
-        let none_i64: Option<i64> = None;
-        check_round_trip(vec![none_i64]);
-
-        let none_isize: Option<isize> = None;
-        check_round_trip(vec![none_isize]);
-    }
-
-    #[test]
-    fn test_struct() {
-        check_round_trip(vec![Struct {
-                                  a: (),
-                                  b: 10,
-                                  c: 11,
-                                  d: 12,
-                                  e: 13,
-                                  f: 14,
-
-                                  g: 15,
-                                  h: 16,
-                                  i: 17,
-                                  j: 18,
-                                  k: 19,
-
-                                  l: 'x',
-                                  m: "abc".to_string(),
-                                  n: 20.5,
-                                  o: 21.5,
-                                  p: false,
-                                  q: None,
-                              }]);
-
-        check_round_trip(vec![Struct {
-                                  a: (),
-                                  b: 101,
-                                  c: 111,
-                                  d: 121,
-                                  e: 131,
-                                  f: 141,
-
-                                  g: -15,
-                                  h: -16,
-                                  i: -17,
-                                  j: -18,
-                                  k: -19,
-
-                                  l: 'y',
-                                  m: "def".to_string(),
-                                  n: -20.5,
-                                  o: -21.5,
-                                  p: true,
-                                  q: Some(1234567),
-                              }]);
-    }
-
-    #[derive(PartialEq, Clone, Debug, RustcEncodable, RustcDecodable)]
-    enum Enum {
-        Variant1,
-        Variant2(usize, f32),
-        Variant3 {
-            a: i32,
-            b: char,
-            c: bool,
-        },
-    }
-
-    #[test]
-    fn test_enum() {
-        check_round_trip(vec![Enum::Variant1,
-                              Enum::Variant2(1, 2.5),
-                              Enum::Variant3 {
-                                  a: 3,
-                                  b: 'b',
-                                  c: false,
-                              },
-                              Enum::Variant3 {
-                                  a: -4,
-                                  b: 'f',
-                                  c: true,
-                              }]);
-    }
-
-    #[test]
-    fn test_sequence() {
-        let mut vec = vec![];
-        for i in -100i64..100i64 {
-            vec.push(i * 100000);
-        }
-
-        check_round_trip(vec![vec]);
-    }
-
-    #[test]
-    fn test_hash_map() {
-        use std::collections::HashMap;
-        let mut map = HashMap::new();
-        for i in -100i64..100i64 {
-            map.insert(i * 100000, i * 10000);
-        }
-
-        check_round_trip(vec![map]);
-    }
-
-    #[test]
-    fn test_tuples() {
-        check_round_trip(vec![('x', (), false, 0.5f32)]);
-        check_round_trip(vec![(9i8, 10u16, 1.5f64)]);
-        check_round_trip(vec![(-12i16, 11u8, 12usize)]);
-        check_round_trip(vec![(1234567isize, 100000000000000u64, 99999999999999i64)]);
-        check_round_trip(vec![(String::new(), "some string".to_string())]);
-    }
-}
diff --git a/src/libserialize/serialize.rs b/src/libserialize/serialize.rs
index 03844b387ac81..cf948078b08c5 100644
--- a/src/libserialize/serialize.rs
+++ b/src/libserialize/serialize.rs
@@ -175,7 +175,7 @@ pub trait Decoder {
     fn read_f64(&mut self) -> Result<f64, Self::Error>;
     fn read_f32(&mut self) -> Result<f32, Self::Error>;
     fn read_char(&mut self) -> Result<char, Self::Error>;
-    fn read_str(&mut self) -> Result<Cow<str>, Self::Error>;
+    fn read_str(&mut self) -> Result<Cow<'_, str>, Self::Error>;
 
     // Compound types:
     fn read_enum<T, F>(&mut self, _name: &str, f: F) -> Result<T, Self::Error>
@@ -824,7 +824,7 @@ impl<T:Decodable> Decodable for Arc<T> {
 /// Implement this trait on your `{Encodable,Decodable}::Error` types
 /// to override the default panic behavior for missing specializations.
 pub trait SpecializationError {
-    /// Create an error for a missing method specialization.
+    /// Creates an error for a missing method specialization.
     /// Defaults to panicking with type, trait & method names.
     /// `S` is the encoder/decoder state type,
     /// `T` is the type being encoded/decoded, and
diff --git a/src/libserialize/tests/json.rs b/src/libserialize/tests/json.rs
new file mode 100644
index 0000000000000..3fb6bda679bc1
--- /dev/null
+++ b/src/libserialize/tests/json.rs
@@ -0,0 +1,1282 @@
+extern crate serialize as rustc_serialize;
+
+use rustc_serialize::{Encodable, Decodable};
+use rustc_serialize::json;
+use json::Json::*;
+use json::ErrorCode::*;
+use json::ParserError::*;
+use json::DecoderError::*;
+use json::JsonEvent::*;
+use json::{Json, from_str, DecodeResult, DecoderError, JsonEvent, Parser, StackElement,
+           Decoder, Encoder, EncoderError};
+
+use Animal::*;
+use std::{i64, u64, f32, f64};
+use std::io::prelude::*;
+use std::collections::BTreeMap;
+use std::string;
+
+#[derive(RustcDecodable, Eq, PartialEq, Debug)]
+struct OptionData {
+    opt: Option<usize>,
+}
+
+#[test]
+fn test_decode_option_none() {
+    let s ="{}";
+    let obj: OptionData = json::decode(s).unwrap();
+    assert_eq!(obj, OptionData { opt: None });
+}
+
+#[test]
+fn test_decode_option_some() {
+    let s = "{ \"opt\": 10 }";
+    let obj: OptionData = json::decode(s).unwrap();
+    assert_eq!(obj, OptionData { opt: Some(10) });
+}
+
+#[test]
+fn test_decode_option_malformed() {
+    check_err::<OptionData>("{ \"opt\": [] }",
+                            ExpectedError("Number".to_string(), "[]".to_string()));
+    check_err::<OptionData>("{ \"opt\": false }",
+                            ExpectedError("Number".to_string(), "false".to_string()));
+}
+
+#[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
+enum Animal {
+    Dog,
+    Frog(string::String, isize)
+}
+
+#[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
+struct Inner {
+    a: (),
+    b: usize,
+    c: Vec<string::String>,
+}
+
+#[derive(PartialEq, RustcEncodable, RustcDecodable, Debug)]
+struct Outer {
+    inner: Vec<Inner>,
+}
+
+fn mk_object(items: &[(string::String, Json)]) -> Json {
+    let mut d = BTreeMap::new();
+
+    for item in items {
+        match *item {
+            (ref key, ref value) => { d.insert((*key).clone(), (*value).clone()); },
+        }
+    };
+
+    Object(d)
+}
+
+#[test]
+fn test_from_str_trait() {
+    let s = "null";
+    assert!(s.parse::<Json>().unwrap() == s.parse().unwrap());
+}
+
+#[test]
+fn test_write_null() {
+    assert_eq!(Null.to_string(), "null");
+    assert_eq!(Null.pretty().to_string(), "null");
+}
+
+#[test]
+fn test_write_i64() {
+    assert_eq!(U64(0).to_string(), "0");
+    assert_eq!(U64(0).pretty().to_string(), "0");
+
+    assert_eq!(U64(1234).to_string(), "1234");
+    assert_eq!(U64(1234).pretty().to_string(), "1234");
+
+    assert_eq!(I64(-5678).to_string(), "-5678");
+    assert_eq!(I64(-5678).pretty().to_string(), "-5678");
+
+    assert_eq!(U64(7650007200025252000).to_string(), "7650007200025252000");
+    assert_eq!(U64(7650007200025252000).pretty().to_string(), "7650007200025252000");
+}
+
+#[test]
+fn test_write_f64() {
+    assert_eq!(F64(3.0).to_string(), "3.0");
+    assert_eq!(F64(3.0).pretty().to_string(), "3.0");
+
+    assert_eq!(F64(3.1).to_string(), "3.1");
+    assert_eq!(F64(3.1).pretty().to_string(), "3.1");
+
+    assert_eq!(F64(-1.5).to_string(), "-1.5");
+    assert_eq!(F64(-1.5).pretty().to_string(), "-1.5");
+
+    assert_eq!(F64(0.5).to_string(), "0.5");
+    assert_eq!(F64(0.5).pretty().to_string(), "0.5");
+
+    assert_eq!(F64(f64::NAN).to_string(), "null");
+    assert_eq!(F64(f64::NAN).pretty().to_string(), "null");
+
+    assert_eq!(F64(f64::INFINITY).to_string(), "null");
+    assert_eq!(F64(f64::INFINITY).pretty().to_string(), "null");
+
+    assert_eq!(F64(f64::NEG_INFINITY).to_string(), "null");
+    assert_eq!(F64(f64::NEG_INFINITY).pretty().to_string(), "null");
+}
+
+#[test]
+fn test_write_str() {
+    assert_eq!(String("".to_string()).to_string(), "\"\"");
+    assert_eq!(String("".to_string()).pretty().to_string(), "\"\"");
+
+    assert_eq!(String("homura".to_string()).to_string(), "\"homura\"");
+    assert_eq!(String("madoka".to_string()).pretty().to_string(), "\"madoka\"");
+}
+
+#[test]
+fn test_write_bool() {
+    assert_eq!(Boolean(true).to_string(), "true");
+    assert_eq!(Boolean(true).pretty().to_string(), "true");
+
+    assert_eq!(Boolean(false).to_string(), "false");
+    assert_eq!(Boolean(false).pretty().to_string(), "false");
+}
+
+#[test]
+fn test_write_array() {
+    assert_eq!(Array(vec![]).to_string(), "[]");
+    assert_eq!(Array(vec![]).pretty().to_string(), "[]");
+
+    assert_eq!(Array(vec![Boolean(true)]).to_string(), "[true]");
+    assert_eq!(
+        Array(vec![Boolean(true)]).pretty().to_string(),
+        "\
+        [\n  \
+            true\n\
+        ]"
+    );
+
+    let long_test_array = Array(vec![
+        Boolean(false),
+        Null,
+        Array(vec![String("foo\nbar".to_string()), F64(3.5)])]);
+
+    assert_eq!(long_test_array.to_string(),
+        "[false,null,[\"foo\\nbar\",3.5]]");
+    assert_eq!(
+        long_test_array.pretty().to_string(),
+        "\
+        [\n  \
+            false,\n  \
+            null,\n  \
+            [\n    \
+                \"foo\\nbar\",\n    \
+                3.5\n  \
+            ]\n\
+        ]"
+    );
+}
+
+#[test]
+fn test_write_object() {
+    assert_eq!(mk_object(&[]).to_string(), "{}");
+    assert_eq!(mk_object(&[]).pretty().to_string(), "{}");
+
+    assert_eq!(
+        mk_object(&[
+            ("a".to_string(), Boolean(true))
+        ]).to_string(),
+        "{\"a\":true}"
+    );
+    assert_eq!(
+        mk_object(&[("a".to_string(), Boolean(true))]).pretty().to_string(),
+        "\
+        {\n  \
+            \"a\": true\n\
+        }"
+    );
+
+    let complex_obj = mk_object(&[
+            ("b".to_string(), Array(vec![
+                mk_object(&[("c".to_string(), String("\x0c\r".to_string()))]),
+                mk_object(&[("d".to_string(), String("".to_string()))])
+            ]))
+        ]);
+
+    assert_eq!(
+        complex_obj.to_string(),
+        "{\
+            \"b\":[\
+                {\"c\":\"\\f\\r\"},\
+                {\"d\":\"\"}\
+            ]\
+        }"
+    );
+    assert_eq!(
+        complex_obj.pretty().to_string(),
+        "\
+        {\n  \
+            \"b\": [\n    \
+                {\n      \
+                    \"c\": \"\\f\\r\"\n    \
+                },\n    \
+                {\n      \
+                    \"d\": \"\"\n    \
+                }\n  \
+            ]\n\
+        }"
+    );
+
+    let a = mk_object(&[
+        ("a".to_string(), Boolean(true)),
+        ("b".to_string(), Array(vec![
+            mk_object(&[("c".to_string(), String("\x0c\r".to_string()))]),
+            mk_object(&[("d".to_string(), String("".to_string()))])
+        ]))
+    ]);
+
+    // We can't compare the strings directly because the object fields be
+    // printed in a different order.
+    assert_eq!(a.clone(), a.to_string().parse().unwrap());
+    assert_eq!(a.clone(), a.pretty().to_string().parse().unwrap());
+}
+
+#[test]
+fn test_write_enum() {
+    let animal = Dog;
+    assert_eq!(
+        json::as_json(&animal).to_string(),
+        "\"Dog\""
+    );
+    assert_eq!(
+        json::as_pretty_json(&animal).to_string(),
+        "\"Dog\""
+    );
+
+    let animal = Frog("Henry".to_string(), 349);
+    assert_eq!(
+        json::as_json(&animal).to_string(),
+        "{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}"
+    );
+    assert_eq!(
+        json::as_pretty_json(&animal).to_string(),
+        "{\n  \
+           \"variant\": \"Frog\",\n  \
+           \"fields\": [\n    \
+             \"Henry\",\n    \
+             349\n  \
+           ]\n\
+         }"
+    );
+}
+
+macro_rules! check_encoder_for_simple {
+    ($value:expr, $expected:expr) => ({
+        let s = json::as_json(&$value).to_string();
+        assert_eq!(s, $expected);
+
+        let s = json::as_pretty_json(&$value).to_string();
+        assert_eq!(s, $expected);
+    })
+}
+
+#[test]
+fn test_write_some() {
+    check_encoder_for_simple!(Some("jodhpurs".to_string()), "\"jodhpurs\"");
+}
+
+#[test]
+fn test_write_none() {
+    check_encoder_for_simple!(None::<string::String>, "null");
+}
+
+#[test]
+fn test_write_char() {
+    check_encoder_for_simple!('a', "\"a\"");
+    check_encoder_for_simple!('\t', "\"\\t\"");
+    check_encoder_for_simple!('\u{0000}', "\"\\u0000\"");
+    check_encoder_for_simple!('\u{001b}', "\"\\u001b\"");
+    check_encoder_for_simple!('\u{007f}', "\"\\u007f\"");
+    check_encoder_for_simple!('\u{00a0}', "\"\u{00a0}\"");
+    check_encoder_for_simple!('\u{abcd}', "\"\u{abcd}\"");
+    check_encoder_for_simple!('\u{10ffff}', "\"\u{10ffff}\"");
+}
+
+#[test]
+fn test_trailing_characters() {
+    assert_eq!(from_str("nulla"),  Err(SyntaxError(TrailingCharacters, 1, 5)));
+    assert_eq!(from_str("truea"),  Err(SyntaxError(TrailingCharacters, 1, 5)));
+    assert_eq!(from_str("falsea"), Err(SyntaxError(TrailingCharacters, 1, 6)));
+    assert_eq!(from_str("1a"),     Err(SyntaxError(TrailingCharacters, 1, 2)));
+    assert_eq!(from_str("[]a"),    Err(SyntaxError(TrailingCharacters, 1, 3)));
+    assert_eq!(from_str("{}a"),    Err(SyntaxError(TrailingCharacters, 1, 3)));
+}
+
+#[test]
+fn test_read_identifiers() {
+    assert_eq!(from_str("n"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(from_str("nul"),  Err(SyntaxError(InvalidSyntax, 1, 4)));
+    assert_eq!(from_str("t"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(from_str("truz"), Err(SyntaxError(InvalidSyntax, 1, 4)));
+    assert_eq!(from_str("f"),    Err(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(from_str("faz"),  Err(SyntaxError(InvalidSyntax, 1, 3)));
+
+    assert_eq!(from_str("null"), Ok(Null));
+    assert_eq!(from_str("true"), Ok(Boolean(true)));
+    assert_eq!(from_str("false"), Ok(Boolean(false)));
+    assert_eq!(from_str(" null "), Ok(Null));
+    assert_eq!(from_str(" true "), Ok(Boolean(true)));
+    assert_eq!(from_str(" false "), Ok(Boolean(false)));
+}
+
+#[test]
+fn test_decode_identifiers() {
+    let v: () = json::decode("null").unwrap();
+    assert_eq!(v, ());
+
+    let v: bool = json::decode("true").unwrap();
+    assert_eq!(v, true);
+
+    let v: bool = json::decode("false").unwrap();
+    assert_eq!(v, false);
+}
+
+#[test]
+fn test_read_number() {
+    assert_eq!(from_str("+"),   Err(SyntaxError(InvalidSyntax, 1, 1)));
+    assert_eq!(from_str("."),   Err(SyntaxError(InvalidSyntax, 1, 1)));
+    assert_eq!(from_str("NaN"), Err(SyntaxError(InvalidSyntax, 1, 1)));
+    assert_eq!(from_str("-"),   Err(SyntaxError(InvalidNumber, 1, 2)));
+    assert_eq!(from_str("00"),  Err(SyntaxError(InvalidNumber, 1, 2)));
+    assert_eq!(from_str("1."),  Err(SyntaxError(InvalidNumber, 1, 3)));
+    assert_eq!(from_str("1e"),  Err(SyntaxError(InvalidNumber, 1, 3)));
+    assert_eq!(from_str("1e+"), Err(SyntaxError(InvalidNumber, 1, 4)));
+
+    assert_eq!(from_str("18446744073709551616"), Err(SyntaxError(InvalidNumber, 1, 20)));
+    assert_eq!(from_str("-9223372036854775809"), Err(SyntaxError(InvalidNumber, 1, 21)));
+
+    assert_eq!(from_str("3"), Ok(U64(3)));
+    assert_eq!(from_str("3.1"), Ok(F64(3.1)));
+    assert_eq!(from_str("-1.2"), Ok(F64(-1.2)));
+    assert_eq!(from_str("0.4"), Ok(F64(0.4)));
+    assert_eq!(from_str("0.4e5"), Ok(F64(0.4e5)));
+    assert_eq!(from_str("0.4e+15"), Ok(F64(0.4e15)));
+    assert_eq!(from_str("0.4e-01"), Ok(F64(0.4e-01)));
+    assert_eq!(from_str(" 3 "), Ok(U64(3)));
+
+    assert_eq!(from_str("-9223372036854775808"), Ok(I64(i64::MIN)));
+    assert_eq!(from_str("9223372036854775807"), Ok(U64(i64::MAX as u64)));
+    assert_eq!(from_str("18446744073709551615"), Ok(U64(u64::MAX)));
+}
+
+#[test]
+fn test_decode_numbers() {
+    let v: f64 = json::decode("3").unwrap();
+    assert_eq!(v, 3.0);
+
+    let v: f64 = json::decode("3.1").unwrap();
+    assert_eq!(v, 3.1);
+
+    let v: f64 = json::decode("-1.2").unwrap();
+    assert_eq!(v, -1.2);
+
+    let v: f64 = json::decode("0.4").unwrap();
+    assert_eq!(v, 0.4);
+
+    let v: f64 = json::decode("0.4e5").unwrap();
+    assert_eq!(v, 0.4e5);
+
+    let v: f64 = json::decode("0.4e15").unwrap();
+    assert_eq!(v, 0.4e15);
+
+    let v: f64 = json::decode("0.4e-01").unwrap();
+    assert_eq!(v, 0.4e-01);
+
+    let v: u64 = json::decode("0").unwrap();
+    assert_eq!(v, 0);
+
+    let v: u64 = json::decode("18446744073709551615").unwrap();
+    assert_eq!(v, u64::MAX);
+
+    let v: i64 = json::decode("-9223372036854775808").unwrap();
+    assert_eq!(v, i64::MIN);
+
+    let v: i64 = json::decode("9223372036854775807").unwrap();
+    assert_eq!(v, i64::MAX);
+
+    let res: DecodeResult<i64> = json::decode("765.25");
+    assert_eq!(res, Err(ExpectedError("Integer".to_string(),
+                                      "765.25".to_string())));
+}
+
+#[test]
+fn test_read_str() {
+    assert_eq!(from_str("\""),    Err(SyntaxError(EOFWhileParsingString, 1, 2)));
+    assert_eq!(from_str("\"lol"), Err(SyntaxError(EOFWhileParsingString, 1, 5)));
+
+    assert_eq!(from_str("\"\""), Ok(String("".to_string())));
+    assert_eq!(from_str("\"foo\""), Ok(String("foo".to_string())));
+    assert_eq!(from_str("\"\\\"\""), Ok(String("\"".to_string())));
+    assert_eq!(from_str("\"\\b\""), Ok(String("\x08".to_string())));
+    assert_eq!(from_str("\"\\n\""), Ok(String("\n".to_string())));
+    assert_eq!(from_str("\"\\r\""), Ok(String("\r".to_string())));
+    assert_eq!(from_str("\"\\t\""), Ok(String("\t".to_string())));
+    assert_eq!(from_str(" \"foo\" "), Ok(String("foo".to_string())));
+    assert_eq!(from_str("\"\\u12ab\""), Ok(String("\u{12ab}".to_string())));
+    assert_eq!(from_str("\"\\uAB12\""), Ok(String("\u{AB12}".to_string())));
+}
+
+#[test]
+fn test_decode_str() {
+    let s = [("\"\"", ""),
+             ("\"foo\"", "foo"),
+             ("\"\\\"\"", "\""),
+             ("\"\\b\"", "\x08"),
+             ("\"\\n\"", "\n"),
+             ("\"\\r\"", "\r"),
+             ("\"\\t\"", "\t"),
+             ("\"\\u12ab\"", "\u{12ab}"),
+             ("\"\\uAB12\"", "\u{AB12}")];
+
+    for &(i, o) in &s {
+        let v: string::String = json::decode(i).unwrap();
+        assert_eq!(v, o);
+    }
+}
+
+#[test]
+fn test_read_array() {
+    assert_eq!(from_str("["),     Err(SyntaxError(EOFWhileParsingValue, 1, 2)));
+    assert_eq!(from_str("[1"),    Err(SyntaxError(EOFWhileParsingArray, 1, 3)));
+    assert_eq!(from_str("[1,"),   Err(SyntaxError(EOFWhileParsingValue, 1, 4)));
+    assert_eq!(from_str("[1,]"),  Err(SyntaxError(InvalidSyntax,        1, 4)));
+    assert_eq!(from_str("[6 7]"), Err(SyntaxError(InvalidSyntax,        1, 4)));
+
+    assert_eq!(from_str("[]"), Ok(Array(vec![])));
+    assert_eq!(from_str("[ ]"), Ok(Array(vec![])));
+    assert_eq!(from_str("[true]"), Ok(Array(vec![Boolean(true)])));
+    assert_eq!(from_str("[ false ]"), Ok(Array(vec![Boolean(false)])));
+    assert_eq!(from_str("[null]"), Ok(Array(vec![Null])));
+    assert_eq!(from_str("[3, 1]"),
+                 Ok(Array(vec![U64(3), U64(1)])));
+    assert_eq!(from_str("\n[3, 2]\n"),
+                 Ok(Array(vec![U64(3), U64(2)])));
+    assert_eq!(from_str("[2, [4, 1]]"),
+           Ok(Array(vec![U64(2), Array(vec![U64(4), U64(1)])])));
+}
+
+#[test]
+fn test_decode_array() {
+    let v: Vec<()> = json::decode("[]").unwrap();
+    assert_eq!(v, []);
+
+    let v: Vec<()> = json::decode("[null]").unwrap();
+    assert_eq!(v, [()]);
+
+    let v: Vec<bool> = json::decode("[true]").unwrap();
+    assert_eq!(v, [true]);
+
+    let v: Vec<isize> = json::decode("[3, 1]").unwrap();
+    assert_eq!(v, [3, 1]);
+
+    let v: Vec<Vec<usize>> = json::decode("[[3], [1, 2]]").unwrap();
+    assert_eq!(v, [vec![3], vec![1, 2]]);
+}
+
+#[test]
+fn test_decode_tuple() {
+    let t: (usize, usize, usize) = json::decode("[1, 2, 3]").unwrap();
+    assert_eq!(t, (1, 2, 3));
+
+    let t: (usize, string::String) = json::decode("[1, \"two\"]").unwrap();
+    assert_eq!(t, (1, "two".to_string()));
+}
+
+#[test]
+fn test_decode_tuple_malformed_types() {
+    assert!(json::decode::<(usize, string::String)>("[1, 2]").is_err());
+}
+
+#[test]
+fn test_decode_tuple_malformed_length() {
+    assert!(json::decode::<(usize, usize)>("[1, 2, 3]").is_err());
+}
+
+#[test]
+fn test_read_object() {
+    assert_eq!(from_str("{"),       Err(SyntaxError(EOFWhileParsingObject, 1, 2)));
+    assert_eq!(from_str("{ "),      Err(SyntaxError(EOFWhileParsingObject, 1, 3)));
+    assert_eq!(from_str("{1"),      Err(SyntaxError(KeyMustBeAString,      1, 2)));
+    assert_eq!(from_str("{ \"a\""), Err(SyntaxError(EOFWhileParsingObject, 1, 6)));
+    assert_eq!(from_str("{\"a\""),  Err(SyntaxError(EOFWhileParsingObject, 1, 5)));
+    assert_eq!(from_str("{\"a\" "), Err(SyntaxError(EOFWhileParsingObject, 1, 6)));
+
+    assert_eq!(from_str("{\"a\" 1"),   Err(SyntaxError(ExpectedColon,         1, 6)));
+    assert_eq!(from_str("{\"a\":"),    Err(SyntaxError(EOFWhileParsingValue,  1, 6)));
+    assert_eq!(from_str("{\"a\":1"),   Err(SyntaxError(EOFWhileParsingObject, 1, 7)));
+    assert_eq!(from_str("{\"a\":1 1"), Err(SyntaxError(InvalidSyntax,         1, 8)));
+    assert_eq!(from_str("{\"a\":1,"),  Err(SyntaxError(EOFWhileParsingObject, 1, 8)));
+
+    assert_eq!(from_str("{}").unwrap(), mk_object(&[]));
+    assert_eq!(from_str("{\"a\": 3}").unwrap(),
+                mk_object(&[("a".to_string(), U64(3))]));
+
+    assert_eq!(from_str(
+                    "{ \"a\": null, \"b\" : true }").unwrap(),
+                mk_object(&[
+                    ("a".to_string(), Null),
+                    ("b".to_string(), Boolean(true))]));
+    assert_eq!(from_str("\n{ \"a\": null, \"b\" : true }\n").unwrap(),
+                mk_object(&[
+                    ("a".to_string(), Null),
+                    ("b".to_string(), Boolean(true))]));
+    assert_eq!(from_str(
+                    "{\"a\" : 1.0 ,\"b\": [ true ]}").unwrap(),
+                mk_object(&[
+                    ("a".to_string(), F64(1.0)),
+                    ("b".to_string(), Array(vec![Boolean(true)]))
+                ]));
+    assert_eq!(from_str(
+                    "{\
+                        \"a\": 1.0, \
+                        \"b\": [\
+                            true,\
+                            \"foo\\nbar\", \
+                            { \"c\": {\"d\": null} } \
+                        ]\
+                    }").unwrap(),
+                mk_object(&[
+                    ("a".to_string(), F64(1.0)),
+                    ("b".to_string(), Array(vec![
+                        Boolean(true),
+                        String("foo\nbar".to_string()),
+                        mk_object(&[
+                            ("c".to_string(), mk_object(&[("d".to_string(), Null)]))
+                        ])
+                    ]))
+                ]));
+}
+
+#[test]
+fn test_decode_struct() {
+    let s = "{
+        \"inner\": [
+            { \"a\": null, \"b\": 2, \"c\": [\"abc\", \"xyz\"] }
+        ]
+    }";
+
+    let v: Outer = json::decode(s).unwrap();
+    assert_eq!(
+        v,
+        Outer {
+            inner: vec![
+                Inner { a: (), b: 2, c: vec!["abc".to_string(), "xyz".to_string()] }
+            ]
+        }
+    );
+}
+
+#[derive(RustcDecodable)]
+struct FloatStruct {
+    f: f64,
+    a: Vec<f64>
+}
+#[test]
+fn test_decode_struct_with_nan() {
+    let s = "{\"f\":null,\"a\":[null,123]}";
+    let obj: FloatStruct = json::decode(s).unwrap();
+    assert!(obj.f.is_nan());
+    assert!(obj.a[0].is_nan());
+    assert_eq!(obj.a[1], 123f64);
+}
+
+#[test]
+fn test_decode_option() {
+    let value: Option<string::String> = json::decode("null").unwrap();
+    assert_eq!(value, None);
+
+    let value: Option<string::String> = json::decode("\"jodhpurs\"").unwrap();
+    assert_eq!(value, Some("jodhpurs".to_string()));
+}
+
+#[test]
+fn test_decode_enum() {
+    let value: Animal = json::decode("\"Dog\"").unwrap();
+    assert_eq!(value, Dog);
+
+    let s = "{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}";
+    let value: Animal = json::decode(s).unwrap();
+    assert_eq!(value, Frog("Henry".to_string(), 349));
+}
+
+#[test]
+fn test_decode_map() {
+    let s = "{\"a\": \"Dog\", \"b\": {\"variant\":\"Frog\",\
+              \"fields\":[\"Henry\", 349]}}";
+    let mut map: BTreeMap<string::String, Animal> = json::decode(s).unwrap();
+
+    assert_eq!(map.remove(&"a".to_string()), Some(Dog));
+    assert_eq!(map.remove(&"b".to_string()), Some(Frog("Henry".to_string(), 349)));
+}
+
+#[test]
+fn test_multiline_errors() {
+    assert_eq!(from_str("{\n  \"foo\":\n \"bar\""),
+        Err(SyntaxError(EOFWhileParsingObject, 3, 8)));
+}
+
+#[derive(RustcDecodable)]
+#[allow(dead_code)]
+struct DecodeStruct {
+    x: f64,
+    y: bool,
+    z: string::String,
+    w: Vec<DecodeStruct>
+}
+#[derive(RustcDecodable)]
+enum DecodeEnum {
+    A(f64),
+    B(string::String)
+}
+fn check_err<T: Decodable>(to_parse: &'static str, expected: DecoderError) {
+    let res: DecodeResult<T> = match from_str(to_parse) {
+        Err(e) => Err(ParseError(e)),
+        Ok(json) => Decodable::decode(&mut Decoder::new(json))
+    };
+    match res {
+        Ok(_) => panic!("`{:?}` parsed & decoded ok, expecting error `{:?}`",
+                           to_parse, expected),
+        Err(ParseError(e)) => panic!("`{:?}` is not valid json: {:?}",
+                                        to_parse, e),
+        Err(e) => {
+            assert_eq!(e, expected);
+        }
+    }
+}
+#[test]
+fn test_decode_errors_struct() {
+    check_err::<DecodeStruct>("[]", ExpectedError("Object".to_string(), "[]".to_string()));
+    check_err::<DecodeStruct>("{\"x\": true, \"y\": true, \"z\": \"\", \"w\": []}",
+                              ExpectedError("Number".to_string(), "true".to_string()));
+    check_err::<DecodeStruct>("{\"x\": 1, \"y\": [], \"z\": \"\", \"w\": []}",
+                              ExpectedError("Boolean".to_string(), "[]".to_string()));
+    check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": {}, \"w\": []}",
+                              ExpectedError("String".to_string(), "{}".to_string()));
+    check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": \"\", \"w\": null}",
+                              ExpectedError("Array".to_string(), "null".to_string()));
+    check_err::<DecodeStruct>("{\"x\": 1, \"y\": true, \"z\": \"\"}",
+                              MissingFieldError("w".to_string()));
+}
+#[test]
+fn test_decode_errors_enum() {
+    check_err::<DecodeEnum>("{}",
+                            MissingFieldError("variant".to_string()));
+    check_err::<DecodeEnum>("{\"variant\": 1}",
+                            ExpectedError("String".to_string(), "1".to_string()));
+    check_err::<DecodeEnum>("{\"variant\": \"A\"}",
+                            MissingFieldError("fields".to_string()));
+    check_err::<DecodeEnum>("{\"variant\": \"A\", \"fields\": null}",
+                            ExpectedError("Array".to_string(), "null".to_string()));
+    check_err::<DecodeEnum>("{\"variant\": \"C\", \"fields\": []}",
+                            UnknownVariantError("C".to_string()));
+}
+
+#[test]
+fn test_find(){
+    let json_value = from_str("{\"dog\" : \"cat\"}").unwrap();
+    let found_str = json_value.find("dog");
+    assert!(found_str.unwrap().as_string().unwrap() == "cat");
+}
+
+#[test]
+fn test_find_path(){
+    let json_value = from_str("{\"dog\":{\"cat\": {\"mouse\" : \"cheese\"}}}").unwrap();
+    let found_str = json_value.find_path(&["dog", "cat", "mouse"]);
+    assert!(found_str.unwrap().as_string().unwrap() == "cheese");
+}
+
+#[test]
+fn test_search(){
+    let json_value = from_str("{\"dog\":{\"cat\": {\"mouse\" : \"cheese\"}}}").unwrap();
+    let found_str = json_value.search("mouse").and_then(|j| j.as_string());
+    assert!(found_str.unwrap() == "cheese");
+}
+
+#[test]
+fn test_index(){
+    let json_value = from_str("{\"animals\":[\"dog\",\"cat\",\"mouse\"]}").unwrap();
+    let ref array = json_value["animals"];
+    assert_eq!(array[0].as_string().unwrap(), "dog");
+    assert_eq!(array[1].as_string().unwrap(), "cat");
+    assert_eq!(array[2].as_string().unwrap(), "mouse");
+}
+
+#[test]
+fn test_is_object(){
+    let json_value = from_str("{}").unwrap();
+    assert!(json_value.is_object());
+}
+
+#[test]
+fn test_as_object(){
+    let json_value = from_str("{}").unwrap();
+    let json_object = json_value.as_object();
+    assert!(json_object.is_some());
+}
+
+#[test]
+fn test_is_array(){
+    let json_value = from_str("[1, 2, 3]").unwrap();
+    assert!(json_value.is_array());
+}
+
+#[test]
+fn test_as_array(){
+    let json_value = from_str("[1, 2, 3]").unwrap();
+    let json_array = json_value.as_array();
+    let expected_length = 3;
+    assert!(json_array.is_some() && json_array.unwrap().len() == expected_length);
+}
+
+#[test]
+fn test_is_string(){
+    let json_value = from_str("\"dog\"").unwrap();
+    assert!(json_value.is_string());
+}
+
+#[test]
+fn test_as_string(){
+    let json_value = from_str("\"dog\"").unwrap();
+    let json_str = json_value.as_string();
+    let expected_str = "dog";
+    assert_eq!(json_str, Some(expected_str));
+}
+
+#[test]
+fn test_is_number(){
+    let json_value = from_str("12").unwrap();
+    assert!(json_value.is_number());
+}
+
+#[test]
+fn test_is_i64(){
+    let json_value = from_str("-12").unwrap();
+    assert!(json_value.is_i64());
+
+    let json_value = from_str("12").unwrap();
+    assert!(!json_value.is_i64());
+
+    let json_value = from_str("12.0").unwrap();
+    assert!(!json_value.is_i64());
+}
+
+#[test]
+fn test_is_u64(){
+    let json_value = from_str("12").unwrap();
+    assert!(json_value.is_u64());
+
+    let json_value = from_str("-12").unwrap();
+    assert!(!json_value.is_u64());
+
+    let json_value = from_str("12.0").unwrap();
+    assert!(!json_value.is_u64());
+}
+
+#[test]
+fn test_is_f64(){
+    let json_value = from_str("12").unwrap();
+    assert!(!json_value.is_f64());
+
+    let json_value = from_str("-12").unwrap();
+    assert!(!json_value.is_f64());
+
+    let json_value = from_str("12.0").unwrap();
+    assert!(json_value.is_f64());
+
+    let json_value = from_str("-12.0").unwrap();
+    assert!(json_value.is_f64());
+}
+
+#[test]
+fn test_as_i64(){
+    let json_value = from_str("-12").unwrap();
+    let json_num = json_value.as_i64();
+    assert_eq!(json_num, Some(-12));
+}
+
+#[test]
+fn test_as_u64(){
+    let json_value = from_str("12").unwrap();
+    let json_num = json_value.as_u64();
+    assert_eq!(json_num, Some(12));
+}
+
+#[test]
+fn test_as_f64(){
+    let json_value = from_str("12.0").unwrap();
+    let json_num = json_value.as_f64();
+    assert_eq!(json_num, Some(12f64));
+}
+
+#[test]
+fn test_is_boolean(){
+    let json_value = from_str("false").unwrap();
+    assert!(json_value.is_boolean());
+}
+
+#[test]
+fn test_as_boolean(){
+    let json_value = from_str("false").unwrap();
+    let json_bool = json_value.as_boolean();
+    let expected_bool = false;
+    assert!(json_bool.is_some() && json_bool.unwrap() == expected_bool);
+}
+
+#[test]
+fn test_is_null(){
+    let json_value = from_str("null").unwrap();
+    assert!(json_value.is_null());
+}
+
+#[test]
+fn test_as_null(){
+    let json_value = from_str("null").unwrap();
+    let json_null = json_value.as_null();
+    let expected_null = ();
+    assert!(json_null.is_some() && json_null.unwrap() == expected_null);
+}
+
+#[test]
+fn test_encode_hashmap_with_numeric_key() {
+    use std::str::from_utf8;
+    use std::collections::HashMap;
+    let mut hm: HashMap<usize, bool> = HashMap::new();
+    hm.insert(1, true);
+    let mut mem_buf = Vec::new();
+    write!(&mut mem_buf, "{}", json::as_pretty_json(&hm)).unwrap();
+    let json_str = from_utf8(&mem_buf[..]).unwrap();
+    match from_str(json_str) {
+        Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
+        _ => {} // it parsed and we are good to go
+    }
+}
+
+#[test]
+fn test_prettyencode_hashmap_with_numeric_key() {
+    use std::str::from_utf8;
+    use std::collections::HashMap;
+    let mut hm: HashMap<usize, bool> = HashMap::new();
+    hm.insert(1, true);
+    let mut mem_buf = Vec::new();
+    write!(&mut mem_buf, "{}", json::as_pretty_json(&hm)).unwrap();
+    let json_str = from_utf8(&mem_buf[..]).unwrap();
+    match from_str(json_str) {
+        Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
+        _ => {} // it parsed and we are good to go
+    }
+}
+
+#[test]
+fn test_prettyencoder_indent_level_param() {
+    use std::str::from_utf8;
+    use std::collections::BTreeMap;
+
+    let mut tree = BTreeMap::new();
+
+    tree.insert("hello".to_string(), String("guten tag".to_string()));
+    tree.insert("goodbye".to_string(), String("sayonara".to_string()));
+
+    let json = Array(
+        // The following layout below should look a lot like
+        // the pretty-printed JSON (indent * x)
+        vec!
+        ( // 0x
+            String("greetings".to_string()), // 1x
+            Object(tree), // 1x + 2x + 2x + 1x
+        ) // 0x
+        // End JSON array (7 lines)
+    );
+
+    // Helper function for counting indents
+    fn indents(source: &str) -> usize {
+        let trimmed = source.trim_start_matches(' ');
+        source.len() - trimmed.len()
+    }
+
+    // Test up to 4 spaces of indents (more?)
+    for i in 0..4 {
+        let mut writer = Vec::new();
+        write!(&mut writer, "{}",
+                json::as_pretty_json(&json).indent(i)).unwrap();
+
+        let printed = from_utf8(&writer[..]).unwrap();
+
+        // Check for indents at each line
+        let lines: Vec<&str> = printed.lines().collect();
+        assert_eq!(lines.len(), 7); // JSON should be 7 lines
+
+        assert_eq!(indents(lines[0]), 0 * i); // [
+        assert_eq!(indents(lines[1]), 1 * i); //   "greetings",
+        assert_eq!(indents(lines[2]), 1 * i); //   {
+        assert_eq!(indents(lines[3]), 2 * i); //     "hello": "guten tag",
+        assert_eq!(indents(lines[4]), 2 * i); //     "goodbye": "sayonara"
+        assert_eq!(indents(lines[5]), 1 * i); //   },
+        assert_eq!(indents(lines[6]), 0 * i); // ]
+
+        // Finally, test that the pretty-printed JSON is valid
+        from_str(printed).ok().expect("Pretty-printed JSON is invalid!");
+    }
+}
+
+#[test]
+fn test_hashmap_with_enum_key() {
+    use std::collections::HashMap;
+    #[derive(RustcEncodable, Eq, Hash, PartialEq, RustcDecodable, Debug)]
+    enum Enum {
+        Foo,
+        #[allow(dead_code)]
+        Bar,
+    }
+    let mut map = HashMap::new();
+    map.insert(Enum::Foo, 0);
+    let result = json::encode(&map).unwrap();
+    assert_eq!(&result[..], r#"{"Foo":0}"#);
+    let decoded: HashMap<Enum, _> = json::decode(&result).unwrap();
+    assert_eq!(map, decoded);
+}
+
+#[test]
+fn test_hashmap_with_numeric_key_can_handle_double_quote_delimited_key() {
+    use std::collections::HashMap;
+    let json_str = "{\"1\":true}";
+    let json_obj = match from_str(json_str) {
+        Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
+        Ok(o) => o
+    };
+    let mut decoder = Decoder::new(json_obj);
+    let _hm: HashMap<usize, bool> = Decodable::decode(&mut decoder).unwrap();
+}
+
+#[test]
+fn test_hashmap_with_numeric_key_will_error_with_string_keys() {
+    use std::collections::HashMap;
+    let json_str = "{\"a\":true}";
+    let json_obj = match from_str(json_str) {
+        Err(_) => panic!("Unable to parse json_str: {:?}", json_str),
+        Ok(o) => o
+    };
+    let mut decoder = Decoder::new(json_obj);
+    let result: Result<HashMap<usize, bool>, DecoderError> = Decodable::decode(&mut decoder);
+    assert_eq!(result, Err(ExpectedError("Number".to_string(), "a".to_string())));
+}
+
+fn assert_stream_equal(src: &str,
+                        expected: Vec<(JsonEvent, Vec<StackElement<'_>>)>) {
+    let mut parser = Parser::new(src.chars());
+    let mut i = 0;
+    loop {
+        let evt = match parser.next() {
+            Some(e) => e,
+            None => { break; }
+        };
+        let (ref expected_evt, ref expected_stack) = expected[i];
+        if !parser.stack().is_equal_to(expected_stack) {
+            panic!("Parser stack is not equal to {:?}", expected_stack);
+        }
+        assert_eq!(&evt, expected_evt);
+        i+=1;
+    }
+}
+#[test]
+fn test_streaming_parser() {
+    assert_stream_equal(
+        r#"{ "foo":"bar", "array" : [0, 1, 2, 3, 4, 5], "idents":[null,true,false]}"#,
+        vec![
+            (ObjectStart,             vec![]),
+              (StringValue("bar".to_string()),   vec![StackElement::Key("foo")]),
+              (ArrayStart,            vec![StackElement::Key("array")]),
+                (U64Value(0),         vec![StackElement::Key("array"), StackElement::Index(0)]),
+                (U64Value(1),         vec![StackElement::Key("array"), StackElement::Index(1)]),
+                (U64Value(2),         vec![StackElement::Key("array"), StackElement::Index(2)]),
+                (U64Value(3),         vec![StackElement::Key("array"), StackElement::Index(3)]),
+                (U64Value(4),         vec![StackElement::Key("array"), StackElement::Index(4)]),
+                (U64Value(5),         vec![StackElement::Key("array"), StackElement::Index(5)]),
+              (ArrayEnd,              vec![StackElement::Key("array")]),
+              (ArrayStart,            vec![StackElement::Key("idents")]),
+                (NullValue,           vec![StackElement::Key("idents"),
+                                           StackElement::Index(0)]),
+                (BooleanValue(true),  vec![StackElement::Key("idents"),
+                                           StackElement::Index(1)]),
+                (BooleanValue(false), vec![StackElement::Key("idents"),
+                                           StackElement::Index(2)]),
+              (ArrayEnd,              vec![StackElement::Key("idents")]),
+            (ObjectEnd,               vec![]),
+        ]
+    );
+}
+fn last_event(src: &str) -> JsonEvent {
+    let mut parser = Parser::new(src.chars());
+    let mut evt = NullValue;
+    loop {
+        evt = match parser.next() {
+            Some(e) => e,
+            None => return evt,
+        }
+    }
+}
+
+#[test]
+fn test_read_object_streaming() {
+    assert_eq!(last_event("{ "),      Error(SyntaxError(EOFWhileParsingObject, 1, 3)));
+    assert_eq!(last_event("{1"),      Error(SyntaxError(KeyMustBeAString,      1, 2)));
+    assert_eq!(last_event("{ \"a\""), Error(SyntaxError(EOFWhileParsingObject, 1, 6)));
+    assert_eq!(last_event("{\"a\""),  Error(SyntaxError(EOFWhileParsingObject, 1, 5)));
+    assert_eq!(last_event("{\"a\" "), Error(SyntaxError(EOFWhileParsingObject, 1, 6)));
+
+    assert_eq!(last_event("{\"a\" 1"),   Error(SyntaxError(ExpectedColon,         1, 6)));
+    assert_eq!(last_event("{\"a\":"),    Error(SyntaxError(EOFWhileParsingValue,  1, 6)));
+    assert_eq!(last_event("{\"a\":1"),   Error(SyntaxError(EOFWhileParsingObject, 1, 7)));
+    assert_eq!(last_event("{\"a\":1 1"), Error(SyntaxError(InvalidSyntax,         1, 8)));
+    assert_eq!(last_event("{\"a\":1,"),  Error(SyntaxError(EOFWhileParsingObject, 1, 8)));
+    assert_eq!(last_event("{\"a\":1,}"), Error(SyntaxError(TrailingComma, 1, 8)));
+
+    assert_stream_equal(
+        "{}",
+        vec![(ObjectStart, vec![]), (ObjectEnd, vec![])]
+    );
+    assert_stream_equal(
+        "{\"a\": 3}",
+        vec![
+            (ObjectStart,        vec![]),
+              (U64Value(3),      vec![StackElement::Key("a")]),
+            (ObjectEnd,          vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "{ \"a\": null, \"b\" : true }",
+        vec![
+            (ObjectStart,           vec![]),
+              (NullValue,           vec![StackElement::Key("a")]),
+              (BooleanValue(true),  vec![StackElement::Key("b")]),
+            (ObjectEnd,             vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "{\"a\" : 1.0 ,\"b\": [ true ]}",
+        vec![
+            (ObjectStart,           vec![]),
+              (F64Value(1.0),       vec![StackElement::Key("a")]),
+              (ArrayStart,          vec![StackElement::Key("b")]),
+                (BooleanValue(true),vec![StackElement::Key("b"), StackElement::Index(0)]),
+              (ArrayEnd,            vec![StackElement::Key("b")]),
+            (ObjectEnd,             vec![]),
+        ]
+    );
+    assert_stream_equal(
+        r#"{
+            "a": 1.0,
+            "b": [
+                true,
+                "foo\nbar",
+                { "c": {"d": null} }
+            ]
+        }"#,
+        vec![
+            (ObjectStart,                   vec![]),
+              (F64Value(1.0),               vec![StackElement::Key("a")]),
+              (ArrayStart,                  vec![StackElement::Key("b")]),
+                (BooleanValue(true),        vec![StackElement::Key("b"),
+                                                StackElement::Index(0)]),
+                (StringValue("foo\nbar".to_string()),  vec![StackElement::Key("b"),
+                                                            StackElement::Index(1)]),
+                (ObjectStart,               vec![StackElement::Key("b"),
+                                                 StackElement::Index(2)]),
+                  (ObjectStart,             vec![StackElement::Key("b"),
+                                                 StackElement::Index(2),
+                                                 StackElement::Key("c")]),
+                    (NullValue,             vec![StackElement::Key("b"),
+                                                 StackElement::Index(2),
+                                                 StackElement::Key("c"),
+                                                 StackElement::Key("d")]),
+                  (ObjectEnd,               vec![StackElement::Key("b"),
+                                                 StackElement::Index(2),
+                                                 StackElement::Key("c")]),
+                (ObjectEnd,                 vec![StackElement::Key("b"),
+                                                 StackElement::Index(2)]),
+              (ArrayEnd,                    vec![StackElement::Key("b")]),
+            (ObjectEnd,                     vec![]),
+        ]
+    );
+}
+#[test]
+fn test_read_array_streaming() {
+    assert_stream_equal(
+        "[]",
+        vec![
+            (ArrayStart, vec![]),
+            (ArrayEnd,   vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[ ]",
+        vec![
+            (ArrayStart, vec![]),
+            (ArrayEnd,   vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[true]",
+        vec![
+            (ArrayStart,             vec![]),
+                (BooleanValue(true), vec![StackElement::Index(0)]),
+            (ArrayEnd,               vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[ false ]",
+        vec![
+            (ArrayStart,              vec![]),
+                (BooleanValue(false), vec![StackElement::Index(0)]),
+            (ArrayEnd,                vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[null]",
+        vec![
+            (ArrayStart,    vec![]),
+                (NullValue, vec![StackElement::Index(0)]),
+            (ArrayEnd,      vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[3, 1]",
+        vec![
+            (ArrayStart,      vec![]),
+                (U64Value(3), vec![StackElement::Index(0)]),
+                (U64Value(1), vec![StackElement::Index(1)]),
+            (ArrayEnd,        vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "\n[3, 2]\n",
+        vec![
+            (ArrayStart,      vec![]),
+                (U64Value(3), vec![StackElement::Index(0)]),
+                (U64Value(2), vec![StackElement::Index(1)]),
+            (ArrayEnd,        vec![]),
+        ]
+    );
+    assert_stream_equal(
+        "[2, [4, 1]]",
+        vec![
+            (ArrayStart,           vec![]),
+                (U64Value(2),      vec![StackElement::Index(0)]),
+                (ArrayStart,       vec![StackElement::Index(1)]),
+                    (U64Value(4),  vec![StackElement::Index(1), StackElement::Index(0)]),
+                    (U64Value(1),  vec![StackElement::Index(1), StackElement::Index(1)]),
+                (ArrayEnd,         vec![StackElement::Index(1)]),
+            (ArrayEnd,             vec![]),
+        ]
+    );
+
+    assert_eq!(last_event("["), Error(SyntaxError(EOFWhileParsingValue, 1,  2)));
+
+    assert_eq!(from_str("["),     Err(SyntaxError(EOFWhileParsingValue, 1, 2)));
+    assert_eq!(from_str("[1"),    Err(SyntaxError(EOFWhileParsingArray, 1, 3)));
+    assert_eq!(from_str("[1,"),   Err(SyntaxError(EOFWhileParsingValue, 1, 4)));
+    assert_eq!(from_str("[1,]"),  Err(SyntaxError(InvalidSyntax,        1, 4)));
+    assert_eq!(from_str("[6 7]"), Err(SyntaxError(InvalidSyntax,        1, 4)));
+
+}
+#[test]
+fn test_trailing_characters_streaming() {
+    assert_eq!(last_event("nulla"),  Error(SyntaxError(TrailingCharacters, 1, 5)));
+    assert_eq!(last_event("truea"),  Error(SyntaxError(TrailingCharacters, 1, 5)));
+    assert_eq!(last_event("falsea"), Error(SyntaxError(TrailingCharacters, 1, 6)));
+    assert_eq!(last_event("1a"),     Error(SyntaxError(TrailingCharacters, 1, 2)));
+    assert_eq!(last_event("[]a"),    Error(SyntaxError(TrailingCharacters, 1, 3)));
+    assert_eq!(last_event("{}a"),    Error(SyntaxError(TrailingCharacters, 1, 3)));
+}
+#[test]
+fn test_read_identifiers_streaming() {
+    assert_eq!(Parser::new("null".chars()).next(), Some(NullValue));
+    assert_eq!(Parser::new("true".chars()).next(), Some(BooleanValue(true)));
+    assert_eq!(Parser::new("false".chars()).next(), Some(BooleanValue(false)));
+
+    assert_eq!(last_event("n"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(last_event("nul"),  Error(SyntaxError(InvalidSyntax, 1, 4)));
+    assert_eq!(last_event("t"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(last_event("truz"), Error(SyntaxError(InvalidSyntax, 1, 4)));
+    assert_eq!(last_event("f"),    Error(SyntaxError(InvalidSyntax, 1, 2)));
+    assert_eq!(last_event("faz"),  Error(SyntaxError(InvalidSyntax, 1, 3)));
+}
+
+#[test]
+fn test_to_json() {
+    use std::collections::{HashMap,BTreeMap};
+    use json::ToJson;
+
+    let array2 = Array(vec![U64(1), U64(2)]);
+    let array3 = Array(vec![U64(1), U64(2), U64(3)]);
+    let object = {
+        let mut tree_map = BTreeMap::new();
+        tree_map.insert("a".to_string(), U64(1));
+        tree_map.insert("b".to_string(), U64(2));
+        Object(tree_map)
+    };
+
+    assert_eq!(array2.to_json(), array2);
+    assert_eq!(object.to_json(), object);
+    assert_eq!(3_isize.to_json(), I64(3));
+    assert_eq!(4_i8.to_json(), I64(4));
+    assert_eq!(5_i16.to_json(), I64(5));
+    assert_eq!(6_i32.to_json(), I64(6));
+    assert_eq!(7_i64.to_json(), I64(7));
+    assert_eq!(8_usize.to_json(), U64(8));
+    assert_eq!(9_u8.to_json(), U64(9));
+    assert_eq!(10_u16.to_json(), U64(10));
+    assert_eq!(11_u32.to_json(), U64(11));
+    assert_eq!(12_u64.to_json(), U64(12));
+    assert_eq!(13.0_f32.to_json(), F64(13.0_f64));
+    assert_eq!(14.0_f64.to_json(), F64(14.0_f64));
+    assert_eq!(().to_json(), Null);
+    assert_eq!(f32::INFINITY.to_json(), Null);
+    assert_eq!(f64::NAN.to_json(), Null);
+    assert_eq!(true.to_json(), Boolean(true));
+    assert_eq!(false.to_json(), Boolean(false));
+    assert_eq!("abc".to_json(), String("abc".to_string()));
+    assert_eq!("abc".to_string().to_json(), String("abc".to_string()));
+    assert_eq!((1_usize, 2_usize).to_json(), array2);
+    assert_eq!((1_usize, 2_usize, 3_usize).to_json(), array3);
+    assert_eq!([1_usize, 2_usize].to_json(), array2);
+    assert_eq!((&[1_usize, 2_usize, 3_usize]).to_json(), array3);
+    assert_eq!((vec![1_usize, 2_usize]).to_json(), array2);
+    assert_eq!(vec![1_usize, 2_usize, 3_usize].to_json(), array3);
+    let mut tree_map = BTreeMap::new();
+    tree_map.insert("a".to_string(), 1 as usize);
+    tree_map.insert("b".to_string(), 2);
+    assert_eq!(tree_map.to_json(), object);
+    let mut hash_map = HashMap::new();
+    hash_map.insert("a".to_string(), 1 as usize);
+    hash_map.insert("b".to_string(), 2);
+    assert_eq!(hash_map.to_json(), object);
+    assert_eq!(Some(15).to_json(), I64(15));
+    assert_eq!(Some(15 as usize).to_json(), U64(15));
+    assert_eq!(None::<isize>.to_json(), Null);
+}
+
+#[test]
+fn test_encode_hashmap_with_arbitrary_key() {
+    use std::collections::HashMap;
+    #[derive(PartialEq, Eq, Hash, RustcEncodable)]
+    struct ArbitraryType(usize);
+    let mut hm: HashMap<ArbitraryType, bool> = HashMap::new();
+    hm.insert(ArbitraryType(1), true);
+    let mut mem_buf = string::String::new();
+    let mut encoder = Encoder::new(&mut mem_buf);
+    let result = hm.encode(&mut encoder);
+    match result.unwrap_err() {
+        EncoderError::BadHashmapKey => (),
+        _ => panic!("expected bad hash map key")
+    }
+}
diff --git a/src/libserialize/tests/opaque.rs b/src/libserialize/tests/opaque.rs
new file mode 100644
index 0000000000000..fff6fc69e7842
--- /dev/null
+++ b/src/libserialize/tests/opaque.rs
@@ -0,0 +1,282 @@
+extern crate serialize as rustc_serialize;
+
+use rustc_serialize::{Encodable, Decodable};
+use rustc_serialize::opaque::{Encoder, Decoder};
+use std::fmt::Debug;
+
+#[derive(PartialEq, Clone, Debug, RustcEncodable, RustcDecodable)]
+struct Struct {
+    a: (),
+    b: u8,
+    c: u16,
+    d: u32,
+    e: u64,
+    f: usize,
+
+    g: i8,
+    h: i16,
+    i: i32,
+    j: i64,
+    k: isize,
+
+    l: char,
+    m: String,
+    n: f32,
+    o: f64,
+    p: bool,
+    q: Option<u32>,
+}
+
+
+fn check_round_trip<T: Encodable + Decodable + PartialEq + Debug>(values: Vec<T>) {
+    let mut encoder = Encoder::new(Vec::new());
+
+    for value in &values {
+        Encodable::encode(&value, &mut encoder).unwrap();
+    }
+
+    let data = encoder.into_inner();
+    let mut decoder = Decoder::new(&data[..], 0);
+
+    for value in values {
+        let decoded = Decodable::decode(&mut decoder).unwrap();
+        assert_eq!(value, decoded);
+    }
+}
+
+#[test]
+fn test_unit() {
+    check_round_trip(vec![(), (), (), ()]);
+}
+
+#[test]
+fn test_u8() {
+    let mut vec = vec![];
+    for i in ::std::u8::MIN..::std::u8::MAX {
+        vec.push(i);
+    }
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_u16() {
+    for i in ::std::u16::MIN..::std::u16::MAX {
+        check_round_trip(vec![1, 2, 3, i, i, i]);
+    }
+}
+
+#[test]
+fn test_u32() {
+    check_round_trip(vec![1, 2, 3, ::std::u32::MIN, 0, 1, ::std::u32::MAX, 2, 1]);
+}
+
+#[test]
+fn test_u64() {
+    check_round_trip(vec![1, 2, 3, ::std::u64::MIN, 0, 1, ::std::u64::MAX, 2, 1]);
+}
+
+#[test]
+fn test_usize() {
+    check_round_trip(vec![1, 2, 3, ::std::usize::MIN, 0, 1, ::std::usize::MAX, 2, 1]);
+}
+
+#[test]
+fn test_i8() {
+    let mut vec = vec![];
+    for i in ::std::i8::MIN..::std::i8::MAX {
+        vec.push(i);
+    }
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_i16() {
+    for i in ::std::i16::MIN..::std::i16::MAX {
+        check_round_trip(vec![-1, 2, -3, i, i, i, 2]);
+    }
+}
+
+#[test]
+fn test_i32() {
+    check_round_trip(vec![-1, 2, -3, ::std::i32::MIN, 0, 1, ::std::i32::MAX, 2, 1]);
+}
+
+#[test]
+fn test_i64() {
+    check_round_trip(vec![-1, 2, -3, ::std::i64::MIN, 0, 1, ::std::i64::MAX, 2, 1]);
+}
+
+#[test]
+fn test_isize() {
+    check_round_trip(vec![-1, 2, -3, ::std::isize::MIN, 0, 1, ::std::isize::MAX, 2, 1]);
+}
+
+#[test]
+fn test_bool() {
+    check_round_trip(vec![false, true, true, false, false]);
+}
+
+#[test]
+fn test_f32() {
+    let mut vec = vec![];
+    for i in -100..100 {
+        vec.push((i as f32) / 3.0);
+    }
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_f64() {
+    let mut vec = vec![];
+    for i in -100..100 {
+        vec.push((i as f64) / 3.0);
+    }
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_char() {
+    let vec = vec!['a', 'b', 'c', 'd', 'A', 'X', ' ', '#', 'Ö', 'Ä', 'µ', '€'];
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_string() {
+    let vec = vec!["abcbuÖeiovÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
+                   "abcbuÖganeiovÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
+                   "abcbuÖganeiovÄnameÜavmpßvmea€µsbpapmaebn".to_string(),
+                   "abcbuÖganeiovÄnameÜavmpßvmeabpnvapeapmaebn".to_string(),
+                   "abcbuÖganeiÄnameÜavmpßvmea€µsbpnvapeapmaebn".to_string(),
+                   "abcbuÖganeiovÄnameÜavmpßvmea€µsbpmaebn".to_string(),
+                   "abcbuÖganeiovÄnameÜavmpßvmea€µnvapeapmaebn".to_string()];
+
+    check_round_trip(vec);
+}
+
+#[test]
+fn test_option() {
+    check_round_trip(vec![Some(-1i8)]);
+    check_round_trip(vec![Some(-2i16)]);
+    check_round_trip(vec![Some(-3i32)]);
+    check_round_trip(vec![Some(-4i64)]);
+    check_round_trip(vec![Some(-5isize)]);
+
+    let none_i8: Option<i8> = None;
+    check_round_trip(vec![none_i8]);
+
+    let none_i16: Option<i16> = None;
+    check_round_trip(vec![none_i16]);
+
+    let none_i32: Option<i32> = None;
+    check_round_trip(vec![none_i32]);
+
+    let none_i64: Option<i64> = None;
+    check_round_trip(vec![none_i64]);
+
+    let none_isize: Option<isize> = None;
+    check_round_trip(vec![none_isize]);
+}
+
+#[test]
+fn test_struct() {
+    check_round_trip(vec![Struct {
+                              a: (),
+                              b: 10,
+                              c: 11,
+                              d: 12,
+                              e: 13,
+                              f: 14,
+
+                              g: 15,
+                              h: 16,
+                              i: 17,
+                              j: 18,
+                              k: 19,
+
+                              l: 'x',
+                              m: "abc".to_string(),
+                              n: 20.5,
+                              o: 21.5,
+                              p: false,
+                              q: None,
+                          }]);
+
+    check_round_trip(vec![Struct {
+                              a: (),
+                              b: 101,
+                              c: 111,
+                              d: 121,
+                              e: 131,
+                              f: 141,
+
+                              g: -15,
+                              h: -16,
+                              i: -17,
+                              j: -18,
+                              k: -19,
+
+                              l: 'y',
+                              m: "def".to_string(),
+                              n: -20.5,
+                              o: -21.5,
+                              p: true,
+                              q: Some(1234567),
+                          }]);
+}
+
+#[derive(PartialEq, Clone, Debug, RustcEncodable, RustcDecodable)]
+enum Enum {
+    Variant1,
+    Variant2(usize, f32),
+    Variant3 {
+        a: i32,
+        b: char,
+        c: bool,
+    },
+}
+
+#[test]
+fn test_enum() {
+    check_round_trip(vec![Enum::Variant1,
+                          Enum::Variant2(1, 2.5),
+                          Enum::Variant3 {
+                              a: 3,
+                              b: 'b',
+                              c: false,
+                          },
+                          Enum::Variant3 {
+                              a: -4,
+                              b: 'f',
+                              c: true,
+                          }]);
+}
+
+#[test]
+fn test_sequence() {
+    let mut vec = vec![];
+    for i in -100i64..100i64 {
+        vec.push(i * 100000);
+    }
+
+    check_round_trip(vec![vec]);
+}
+
+#[test]
+fn test_hash_map() {
+    use std::collections::HashMap;
+    let mut map = HashMap::new();
+    for i in -100i64..100i64 {
+        map.insert(i * 100000, i * 10000);
+    }
+
+    check_round_trip(vec![map]);
+}
+
+#[test]
+fn test_tuples() {
+    check_round_trip(vec![('x', (), false, 0.5f32)]);
+    check_round_trip(vec![(9i8, 10u16, 1.5f64)]);
+    check_round_trip(vec![(-12i16, 11u8, 12usize)]);
+    check_round_trip(vec![(1234567isize, 100000000000000u64, 99999999999999i64)]);
+    check_round_trip(vec![(String::new(), "some string".to_string())]);
+}
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 92876f7f2d804..7d60a170422b3 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -47,7 +47,7 @@ fortanix-sgx-abi = { version = "0.3.2", features = ['rustc-dep-of-std'] }
 cc = "1.0"
 
 [features]
-default = ["compiler_builtins_c"]
+default = ["compiler_builtins_c", "std_detect_file_io", "std_detect_dlsym_getauxval"]
 
 backtrace = ["backtrace-sys"]
 panic-unwind = ["panic_unwind"]
@@ -66,3 +66,8 @@ wasm_syscall = []
 # the environment for hooking up some thread-related information like the
 # current thread id and accessing/getting the current thread's TCB
 wasm-bindgen-threads = []
+
+# Enable std_detect default features for stdsimd:
+# https://github.com/rust-lang-nursery/stdsimd/blob/master/crates/std_detect/Cargo.toml
+std_detect_file_io = []
+std_detect_dlsym_getauxval = []
diff --git a/src/libstd/alloc.rs b/src/libstd/alloc.rs
index 537f56a8da71d..8b6e5680c2d6c 100644
--- a/src/libstd/alloc.rs
+++ b/src/libstd/alloc.rs
@@ -95,11 +95,11 @@ pub use alloc_crate::alloc::*;
 ///
 /// ```rust
 /// use std::alloc::{System, GlobalAlloc, Layout};
-/// use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering::SeqCst};
+/// use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
 ///
 /// struct Counter;
 ///
-/// static ALLOCATED: AtomicUsize = ATOMIC_USIZE_INIT;
+/// static ALLOCATED: AtomicUsize = AtomicUsize::new(0);
 ///
 /// unsafe impl GlobalAlloc for Counter {
 ///     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 91c4e990e007d..a82b9498074c2 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -370,7 +370,7 @@ const DISPLACEMENT_THRESHOLD: usize = 128;
 /// }
 ///
 /// impl Viking {
-///     /// Create a new Viking.
+///     /// Creates a new Viking.
 ///     fn new(name: &str, country: &str) -> Viking {
 ///         Viking { name: name.to_string(), country: country.to_string() }
 ///     }
@@ -556,7 +556,7 @@ fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>)
     (retkey, retval, gap.into_table())
 }
 
-/// Perform robin hood bucket stealing at the given `bucket`. You must
+/// Performs robin hood bucket stealing at the given `bucket`. You must
 /// also pass that bucket's displacement so we don't have to recalculate it.
 ///
 /// `hash`, `key`, and `val` are the elements to "robin hood" into the hashtable.
@@ -1214,7 +1214,7 @@ impl<K, V, S> HashMap<K, V, S>
         self.table.size()
     }
 
-    /// Returns true if the map contains no elements.
+    /// Returns `true` if the map contains no elements.
     ///
     /// # Examples
     ///
@@ -1332,7 +1332,7 @@ impl<K, V, S> HashMap<K, V, S>
         self.search(k).map(|bucket| bucket.into_refs())
     }
 
-    /// Returns true if the map contains a value for the specified key.
+    /// Returns `true` if the map contains a value for the specified key.
     ///
     /// The key may be any borrowed form of the map's key type, but
     /// [`Hash`] and [`Eq`] on the borrowed form *must* match those for
@@ -1641,7 +1641,7 @@ impl<K, V, S> Default for HashMap<K, V, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, Q: ?Sized, V, S> Index<&'a Q> for HashMap<K, V, S>
+impl<K, Q: ?Sized, V, S> Index<&Q> for HashMap<K, V, S>
     where K: Eq + Hash + Borrow<Q>,
           Q: Eq + Hash,
           S: BuildHasher
@@ -1673,14 +1673,14 @@ pub struct Iter<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: Debug, V: Debug> fmt::Debug for Iter<'a, K, V> {
+impl<K: Debug, V: Debug> fmt::Debug for Iter<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -1726,14 +1726,14 @@ pub struct Keys<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Keys<'a, K, V> {
-    fn clone(&self) -> Keys<'a, K, V> {
+impl<K, V> Clone for Keys<'_, K, V> {
+    fn clone(&self) -> Self {
         Keys { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: Debug, V> fmt::Debug for Keys<'a, K, V> {
+impl<K: Debug, V> fmt::Debug for Keys<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -1755,14 +1755,14 @@ pub struct Values<'a, K: 'a, V: 'a> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Values<'a, K, V> {
-    fn clone(&self) -> Values<'a, K, V> {
+impl<K, V> Clone for Values<'_, K, V> {
+    fn clone(&self) -> Self {
         Values { inner: self.inner.clone() }
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V: Debug> fmt::Debug for Values<'a, K, V> {
+impl<K, V: Debug> fmt::Debug for Values<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list()
             .entries(self.clone())
@@ -1896,7 +1896,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
     where S: BuildHasher,
           K: Eq + Hash,
 {
-    /// Create a `RawEntryMut` from the given key.
+    /// Creates a `RawEntryMut` from the given key.
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn from_key<Q: ?Sized>(self, k: &Q) -> RawEntryMut<'a, K, V, S>
         where K: Borrow<Q>,
@@ -1907,7 +1907,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
         self.from_key_hashed_nocheck(hasher.finish(), k)
     }
 
-    /// Create a `RawEntryMut` from the given key and its hash.
+    /// Creates a `RawEntryMut` from the given key and its hash.
     #[inline]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> RawEntryMut<'a, K, V, S>
@@ -1939,7 +1939,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
             }
         }
     }
-    /// Create a `RawEntryMut` from the given hash.
+    /// Creates a `RawEntryMut` from the given hash.
     #[inline]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn from_hash<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
@@ -2241,7 +2241,7 @@ impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawEntryBuilderMut<'a, K, V, S> {
+impl<K, V, S> Debug for RawEntryBuilderMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawEntryBuilder")
          .finish()
@@ -2249,7 +2249,7 @@ impl<'a, K, V, S> Debug for RawEntryBuilderMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K: Debug, V: Debug, S> Debug for RawEntryMut<'a, K, V, S> {
+impl<K: Debug, V: Debug, S> Debug for RawEntryMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             RawEntryMut::Vacant(ref v) => {
@@ -2267,7 +2267,7 @@ impl<'a, K: Debug, V: Debug, S> Debug for RawEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawOccupiedEntryMut")
          .field("key", self.key())
@@ -2277,7 +2277,7 @@ impl<'a, K: Debug, V: Debug> Debug for RawOccupiedEntryMut<'a, K, V> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawVacantEntryMut<'a, K, V, S> {
+impl<K, V, S> Debug for RawVacantEntryMut<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawVacantEntryMut")
          .finish()
@@ -2285,7 +2285,7 @@ impl<'a, K, V, S> Debug for RawVacantEntryMut<'a, K, V, S> {
 }
 
 #[unstable(feature = "hash_raw_entry", issue = "56167")]
-impl<'a, K, V, S> Debug for RawEntryBuilder<'a, K, V, S> {
+impl<K, V, S> Debug for RawEntryBuilder<'_, K, V, S> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RawEntryBuilder")
          .finish()
@@ -2312,7 +2312,7 @@ pub enum Entry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for Entry<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for Entry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             Vacant(ref v) => {
@@ -2340,7 +2340,7 @@ pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a + Debug> Debug for OccupiedEntry<'a, K, V> {
+impl<K: Debug, V: Debug> Debug for OccupiedEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("OccupiedEntry")
             .field("key", self.key())
@@ -2361,7 +2361,7 @@ pub struct VacantEntry<'a, K: 'a, V: 'a> {
 }
 
 #[stable(feature= "debug_hash_map", since = "1.12.0")]
-impl<'a, K: 'a + Debug, V: 'a> Debug for VacantEntry<'a, K, V> {
+impl<K: Debug, V> Debug for VacantEntry<'_, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_tuple("VacantEntry")
             .field(self.key())
@@ -2448,7 +2448,7 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
@@ -2456,7 +2456,7 @@ impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Iter<'a, K, V> {}
+impl<K, V> FusedIterator for Iter<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K, V> Iterator for IterMut<'a, K, V> {
@@ -2472,17 +2472,17 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for IterMut<'a, K, V> {}
+impl<K, V> FusedIterator for IterMut<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for IterMut<'a, K, V>
+impl<K, V> fmt::Debug for IterMut<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
@@ -2539,14 +2539,14 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
+impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Keys<'a, K, V> {}
+impl<K, V> FusedIterator for Keys<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, K, V> Iterator for Values<'a, K, V> {
@@ -2562,14 +2562,14 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
+impl<K, V> ExactSizeIterator for Values<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Values<'a, K, V> {}
+impl<K, V> FusedIterator for Values<'_, K, V> {}
 
 #[stable(feature = "map_values_mut", since = "1.10.0")]
 impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
@@ -2585,17 +2585,17 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     }
 }
 #[stable(feature = "map_values_mut", since = "1.10.0")]
-impl<'a, K, V> ExactSizeIterator for ValuesMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for ValuesMut<'a, K, V> {}
+impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for ValuesMut<'a, K, V>
+impl<K, V> fmt::Debug for ValuesMut<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
@@ -2620,17 +2620,17 @@ impl<'a, K, V> Iterator for Drain<'a, K, V> {
     }
 }
 #[stable(feature = "drain", since = "1.6.0")]
-impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
     #[inline]
     fn len(&self) -> usize {
         self.inner.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K, V> FusedIterator for Drain<'a, K, V> {}
+impl<K, V> FusedIterator for Drain<'_, K, V> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K, V> fmt::Debug for Drain<'a, K, V>
+impl<K, V> fmt::Debug for Drain<'_, K, V>
     where K: fmt::Debug,
           V: fmt::Debug,
 {
diff --git a/src/libstd/collections/hash/set.rs b/src/libstd/collections/hash/set.rs
index c55dd049ec60f..bfd36a8456363 100644
--- a/src/libstd/collections/hash/set.rs
+++ b/src/libstd/collections/hash/set.rs
@@ -471,7 +471,7 @@ impl<T, S> HashSet<T, S>
         self.map.len()
     }
 
-    /// Returns true if the set contains no elements.
+    /// Returns `true` if the set contains no elements.
     ///
     /// # Examples
     ///
@@ -696,7 +696,7 @@ impl<T, S> HashSet<T, S>
         Recover::replace(&mut self.map, value)
     }
 
-    /// Removes a value from the set. Returns `true` if the value was
+    /// Removes a value from the set. Returns whether the value was
     /// present in the set.
     ///
     /// The value may be any borrowed form of the set's value type, but
@@ -1112,8 +1112,8 @@ impl<T, S> IntoIterator for HashSet<T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> Clone for Iter<'a, K> {
-    fn clone(&self) -> Iter<'a, K> {
+impl<K> Clone for Iter<'_, K> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }
@@ -1129,16 +1129,16 @@ impl<'a, K> Iterator for Iter<'a, K> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Iter<'a, K> {
+impl<K> ExactSizeIterator for Iter<'_, K> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K> FusedIterator for Iter<'a, K> {}
+impl<K> FusedIterator for Iter<'_, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: fmt::Debug> fmt::Debug for Iter<'a, K> {
+impl<K: fmt::Debug> fmt::Debug for Iter<'_, K> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_list().entries(self.clone()).finish()
     }
@@ -1187,16 +1187,16 @@ impl<'a, K> Iterator for Drain<'a, K> {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Drain<'a, K> {
+impl<K> ExactSizeIterator for Drain<'_, K> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, K> FusedIterator for Drain<'a, K> {}
+impl<K> FusedIterator for Drain<'_, K> {}
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, K: fmt::Debug> fmt::Debug for Drain<'a, K> {
+impl<K: fmt::Debug> fmt::Debug for Drain<'_, K> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let entries_iter = self.iter
             .inner
@@ -1207,8 +1207,8 @@ impl<'a, K: fmt::Debug> fmt::Debug for Drain<'a, K> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Intersection<'a, T, S> {
-    fn clone(&self) -> Intersection<'a, T, S> {
+impl<T, S> Clone for Intersection<'_, T, S> {
+    fn clone(&self) -> Self {
         Intersection { iter: self.iter.clone(), ..*self }
     }
 }
@@ -1236,7 +1236,7 @@ impl<'a, T, S> Iterator for Intersection<'a, T, S>
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Intersection<'a, T, S>
+impl<T, S> fmt::Debug for Intersection<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1246,15 +1246,15 @@ impl<'a, T, S> fmt::Debug for Intersection<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Intersection<'a, T, S>
+impl<T, S> FusedIterator for Intersection<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Difference<'a, T, S> {
-    fn clone(&self) -> Difference<'a, T, S> {
+impl<T, S> Clone for Difference<'_, T, S> {
+    fn clone(&self) -> Self {
         Difference { iter: self.iter.clone(), ..*self }
     }
 }
@@ -1282,14 +1282,14 @@ impl<'a, T, S> Iterator for Difference<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Difference<'a, T, S>
+impl<T, S> FusedIterator for Difference<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Difference<'a, T, S>
+impl<T, S> fmt::Debug for Difference<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1299,8 +1299,8 @@ impl<'a, T, S> fmt::Debug for Difference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for SymmetricDifference<'a, T, S> {
-    fn clone(&self) -> SymmetricDifference<'a, T, S> {
+impl<T, S> Clone for SymmetricDifference<'_, T, S> {
+    fn clone(&self) -> Self {
         SymmetricDifference { iter: self.iter.clone() }
     }
 }
@@ -1321,14 +1321,14 @@ impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S>
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for SymmetricDifference<'a, T, S>
+impl<T, S> FusedIterator for SymmetricDifference<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for SymmetricDifference<'a, T, S>
+impl<T, S> fmt::Debug for SymmetricDifference<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
@@ -1338,21 +1338,21 @@ impl<'a, T, S> fmt::Debug for SymmetricDifference<'a, T, S>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S> Clone for Union<'a, T, S> {
-    fn clone(&self) -> Union<'a, T, S> {
+impl<T, S> Clone for Union<'_, T, S> {
+    fn clone(&self) -> Self {
         Union { iter: self.iter.clone() }
     }
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a, T, S> FusedIterator for Union<'a, T, S>
+impl<T, S> FusedIterator for Union<'_, T, S>
     where T: Eq + Hash,
           S: BuildHasher
 {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T, S> fmt::Debug for Union<'a, T, S>
+impl<T, S> fmt::Debug for Union<'_, T, S>
     where T: fmt::Debug + Eq + Hash,
           S: BuildHasher
 {
diff --git a/src/libstd/collections/hash/table.rs b/src/libstd/collections/hash/table.rs
index 28beb80612ceb..865431252acf6 100644
--- a/src/libstd/collections/hash/table.rs
+++ b/src/libstd/collections/hash/table.rs
@@ -248,11 +248,11 @@ impl<K, V, M> FullBucket<K, V, M> {
     pub fn into_table(self) -> M {
         self.table
     }
-    /// Get the raw index.
+    /// Gets the raw index.
     pub fn index(&self) -> usize {
         self.raw.idx
     }
-    /// Get the raw bucket.
+    /// Gets the raw bucket.
     pub fn raw(&self) -> RawBucket<K, V> {
         self.raw
     }
@@ -270,7 +270,7 @@ impl<K, V, M> EmptyBucket<K, V, M> {
 }
 
 impl<K, V, M> Bucket<K, V, M> {
-    /// Get the raw index.
+    /// Gets the raw index.
     pub fn index(&self) -> usize {
         self.raw.idx
     }
@@ -296,7 +296,7 @@ pub trait Put<K, V> {
 }
 
 
-impl<'t, K, V> Put<K, V> for &'t mut RawTable<K, V> {
+impl<K, V> Put<K, V> for &mut RawTable<K, V> {
     unsafe fn borrow_table_mut(&mut self) -> &mut RawTable<K, V> {
         *self
     }
@@ -503,7 +503,7 @@ impl<K, V, M: Deref<Target = RawTable<K, V>>> FullBucket<K, V, M> {
         }
     }
 
-    /// Get the distance between this bucket and the 'ideal' location
+    /// Gets the distance between this bucket and the 'ideal' location
     /// as determined by the key's hash stored in it.
     ///
     /// In the cited blog posts above, this is called the "distance to
@@ -839,12 +839,12 @@ impl<K, V> RawTable<K, V> {
         }
     }
 
-    /// Set the table tag
+    /// Sets the table tag.
     pub fn set_tag(&mut self, value: bool) {
         self.hashes.set_tag(value)
     }
 
-    /// Get the table tag
+    /// Gets the table tag.
     pub fn tag(&self) -> bool {
         self.hashes.tag()
     }
@@ -865,8 +865,8 @@ struct RawBuckets<'a, K, V> {
 }
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for RawBuckets<'a, K, V> {
-    fn clone(&self) -> RawBuckets<'a, K, V> {
+impl<K, V> Clone for RawBuckets<'_, K, V> {
+    fn clone(&self) -> Self {
         RawBuckets {
             raw: self.raw,
             elems_left: self.elems_left,
@@ -901,7 +901,7 @@ impl<'a, K, V> Iterator for RawBuckets<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for RawBuckets<'a, K, V> {
+impl<K, V> ExactSizeIterator for RawBuckets<'_, K, V> {
     fn len(&self) -> usize {
         self.elems_left
     }
@@ -912,12 +912,12 @@ pub struct Iter<'a, K: 'a, V: 'a> {
     iter: RawBuckets<'a, K, V>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for Iter<'a, K, V> {}
-unsafe impl<'a, K: Sync, V: Sync> Send for Iter<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for Iter<'_, K, V> {}
+unsafe impl<K: Sync, V: Sync> Send for Iter<'_, K, V> {}
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter {
             iter: self.iter.clone(),
         }
@@ -931,10 +931,10 @@ pub struct IterMut<'a, K: 'a, V: 'a> {
     _marker: marker::PhantomData<&'a mut V>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for IterMut<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for IterMut<'_, K, V> {}
 // Both K: Sync and K: Send are correct for IterMut's Send impl,
 // but Send is the more useful bound
-unsafe impl<'a, K: Send, V: Send> Send for IterMut<'a, K, V> {}
+unsafe impl<K: Send, V: Send> Send for IterMut<'_, K, V> {}
 
 impl<'a, K: 'a, V: 'a> IterMut<'a, K, V> {
     pub fn iter(&self) -> Iter<K, V> {
@@ -968,8 +968,8 @@ pub struct Drain<'a, K: 'a, V: 'a> {
     marker: marker::PhantomData<&'a RawTable<K, V>>,
 }
 
-unsafe impl<'a, K: Sync, V: Sync> Sync for Drain<'a, K, V> {}
-unsafe impl<'a, K: Send, V: Send> Send for Drain<'a, K, V> {}
+unsafe impl<K: Sync, V: Sync> Sync for Drain<'_, K, V> {}
+unsafe impl<K: Send, V: Send> Send for Drain<'_, K, V> {}
 
 impl<'a, K, V> Drain<'a, K, V> {
     pub fn iter(&self) -> Iter<K, V> {
@@ -994,7 +994,7 @@ impl<'a, K, V> Iterator for Iter<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
+impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
@@ -1015,7 +1015,7 @@ impl<'a, K, V> Iterator for IterMut<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
+impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
@@ -1064,13 +1064,13 @@ impl<'a, K, V> Iterator for Drain<'a, K, V> {
     }
 }
 
-impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
+impl<K, V> ExactSizeIterator for Drain<'_, K, V> {
     fn len(&self) -> usize {
         self.iter.len()
     }
 }
 
-impl<'a, K: 'a, V: 'a> Drop for Drain<'a, K, V> {
+impl<K, V> Drop for Drain<'_, K, V> {
     fn drop(&mut self) {
         self.for_each(drop);
     }
diff --git a/src/libstd/collections/mod.rs b/src/libstd/collections/mod.rs
index ef397283ca4fb..9ebeff48426f5 100644
--- a/src/libstd/collections/mod.rs
+++ b/src/libstd/collections/mod.rs
@@ -323,8 +323,8 @@
 //! // A client of the bar. They have a blood alcohol level.
 //! struct Person { blood_alcohol: f32 }
 //!
-//! // All the orders made to the bar, by client id.
-//! let orders = vec![1,2,1,2,3,4,1,2,2,3,4,1,1,1];
+//! // All the orders made to the bar, by client ID.
+//! let orders = vec![1, 2, 1, 2, 3, 4, 1, 2, 2, 3, 4, 1, 1, 1];
 //!
 //! // Our clients.
 //! let mut blood_alcohol = BTreeMap::new();
diff --git a/src/libstd/env.rs b/src/libstd/env.rs
index 1f3b264c414a2..543973ab991df 100644
--- a/src/libstd/env.rs
+++ b/src/libstd/env.rs
@@ -399,7 +399,7 @@ impl<'a> Iterator for SplitPaths<'a> {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a> fmt::Debug for SplitPaths<'a> {
+impl fmt::Debug for SplitPaths<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.pad("SplitPaths { .. }")
     }
diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index 2f9efb3f0fb57..ef8c97bebdffd 100644
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -195,11 +195,9 @@ pub trait Error: Debug + Display {
     #[stable(feature = "error_source", since = "1.30.0")]
     fn source(&self) -> Option<&(dyn Error + 'static)> { None }
 
-    /// Get the `TypeId` of `self`
+    /// Gets the `TypeId` of `self`
     #[doc(hidden)]
-    #[unstable(feature = "error_type_id",
-               reason = "unclear whether to commit to this public implementation detail",
-               issue = "27745")]
+    #[stable(feature = "error_type_id", since = "1.34.0")]
     fn type_id(&self) -> TypeId where Self: 'static {
         TypeId::of::<Self>()
     }
@@ -566,7 +564,7 @@ impl Error for char::ParseCharError {
 
 // copied from any.rs
 impl dyn Error + 'static {
-    /// Returns true if the boxed type is the same as `T`
+    /// Returns `true` if the boxed type is the same as `T`
     #[stable(feature = "error_downcast", since = "1.3.0")]
     #[inline]
     pub fn is<T: Error + 'static>(&self) -> bool {
@@ -669,6 +667,158 @@ impl dyn Error {
             Err(self)
         }
     }
+
+    /// Returns an iterator starting with the current error and continuing with
+    /// recursively calling [`source`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(error_iter)]
+    /// use std::error::Error;
+    /// use std::fmt;
+    ///
+    /// #[derive(Debug)]
+    /// struct A;
+    ///
+    /// #[derive(Debug)]
+    /// struct B(Option<Box<dyn Error + 'static>>);
+    ///
+    /// impl fmt::Display for A {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "A")
+    ///     }
+    /// }
+    ///
+    /// impl fmt::Display for B {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "B")
+    ///     }
+    /// }
+    ///
+    /// impl Error for A {}
+    ///
+    /// impl Error for B {
+    ///     fn source(&self) -> Option<&(dyn Error + 'static)> {
+    ///         self.0.as_ref().map(|e| e.as_ref())
+    ///     }
+    /// }
+    ///
+    /// let b = B(Some(Box::new(A)));
+    ///
+    /// // let err : Box<Error> = b.into(); // or
+    /// let err = &b as &(dyn Error);
+    ///
+    /// let mut iter = err.iter_chain();
+    ///
+    /// assert_eq!("B".to_string(), iter.next().unwrap().to_string());
+    /// assert_eq!("A".to_string(), iter.next().unwrap().to_string());
+    /// assert!(iter.next().is_none());
+    /// assert!(iter.next().is_none());
+    /// ```
+    ///
+    /// [`source`]: trait.Error.html#method.source
+    #[unstable(feature = "error_iter", issue = "58520")]
+    #[inline]
+    pub fn iter_chain(&self) -> ErrorIter {
+        ErrorIter {
+            current: Some(self),
+        }
+    }
+
+    /// Returns an iterator starting with the [`source`] of this error
+    /// and continuing with recursively calling [`source`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(error_iter)]
+    /// use std::error::Error;
+    /// use std::fmt;
+    ///
+    /// #[derive(Debug)]
+    /// struct A;
+    ///
+    /// #[derive(Debug)]
+    /// struct B(Option<Box<dyn Error + 'static>>);
+    ///
+    /// #[derive(Debug)]
+    /// struct C(Option<Box<dyn Error + 'static>>);
+    ///
+    /// impl fmt::Display for A {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "A")
+    ///     }
+    /// }
+    ///
+    /// impl fmt::Display for B {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "B")
+    ///     }
+    /// }
+    ///
+    /// impl fmt::Display for C {
+    ///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    ///         write!(f, "C")
+    ///     }
+    /// }
+    ///
+    /// impl Error for A {}
+    ///
+    /// impl Error for B {
+    ///     fn source(&self) -> Option<&(dyn Error + 'static)> {
+    ///         self.0.as_ref().map(|e| e.as_ref())
+    ///     }
+    /// }
+    ///
+    /// impl Error for C {
+    ///     fn source(&self) -> Option<&(dyn Error + 'static)> {
+    ///         self.0.as_ref().map(|e| e.as_ref())
+    ///     }
+    /// }
+    ///
+    /// let b = B(Some(Box::new(A)));
+    /// let c = C(Some(Box::new(b)));
+    ///
+    /// // let err : Box<Error> = c.into(); // or
+    /// let err = &c as &(dyn Error);
+    ///
+    /// let mut iter = err.iter_sources();
+    ///
+    /// assert_eq!("B".to_string(), iter.next().unwrap().to_string());
+    /// assert_eq!("A".to_string(), iter.next().unwrap().to_string());
+    /// assert!(iter.next().is_none());
+    /// assert!(iter.next().is_none());
+    /// ```
+    ///
+    /// [`source`]: trait.Error.html#method.source
+    #[inline]
+    #[unstable(feature = "error_iter", issue = "58520")]
+    pub fn iter_sources(&self) -> ErrorIter {
+        ErrorIter {
+            current: self.source(),
+        }
+    }
+}
+
+/// An iterator over [`Error`]
+///
+/// [`Error`]: trait.Error.html
+#[unstable(feature = "error_iter", issue = "58520")]
+#[derive(Copy, Clone, Debug)]
+pub struct ErrorIter<'a> {
+    current: Option<&'a (dyn Error + 'static)>,
+}
+
+#[unstable(feature = "error_iter", issue = "58520")]
+impl<'a> Iterator for ErrorIter<'a> {
+    type Item = &'a (dyn Error + 'static);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let current = self.current;
+        self.current = self.current.and_then(Error::source);
+        current
+    }
 }
 
 impl dyn Error + Send {
diff --git a/src/libstd/f64.rs b/src/libstd/f64.rs
index 2e0383ccef58e..7fa7b80751938 100644
--- a/src/libstd/f64.rs
+++ b/src/libstd/f64.rs
@@ -250,7 +250,7 @@ impl f64 {
     /// Calculates the least nonnegative remainder of `self (mod rhs)`.
     ///
     /// In particular, the return value `r` satisfies `0.0 <= r < rhs.abs()` in
-    /// most cases.  However, due to a floating point round-off error it can
+    /// most cases. However, due to a floating point round-off error it can
     /// result in `r == rhs.abs()`, violating the mathematical definition, if
     /// `self` is much smaller than `rhs.abs()` in magnitude and `self < 0.0`.
     /// This result is not an element of the function's codomain, but it is the
diff --git a/src/libstd/ffi/c_str.rs b/src/libstd/ffi/c_str.rs
index 765452e0288ba..0ef7224282782 100644
--- a/src/libstd/ffi/c_str.rs
+++ b/src/libstd/ffi/c_str.rs
@@ -377,7 +377,7 @@ impl CString {
     ///
     /// # Examples
     ///
-    /// Create a `CString`, pass ownership to an `extern` function (via raw pointer), then retake
+    /// Creates a `CString`, pass ownership to an `extern` function (via raw pointer), then retake
     /// ownership with `from_raw`:
     ///
     /// ```ignore (extern-declaration)
@@ -659,8 +659,8 @@ impl fmt::Debug for CStr {
 }
 
 #[stable(feature = "cstr_default", since = "1.10.0")]
-impl<'a> Default for &'a CStr {
-    fn default() -> &'a CStr {
+impl Default for &CStr {
+    fn default() -> Self {
         const SLICE: &[c_char] = &[0];
         unsafe { CStr::from_ptr(SLICE.as_ptr()) }
     }
diff --git a/src/libstd/ffi/mod.rs b/src/libstd/ffi/mod.rs
index 62081e713f139..7a38f0ebd5a57 100644
--- a/src/libstd/ffi/mod.rs
+++ b/src/libstd/ffi/mod.rs
@@ -169,7 +169,7 @@ pub use core::ffi::c_void;
 #[unstable(feature = "c_variadic",
            reason = "the `c_variadic` feature has not been properly tested on \
                      all supported platforms",
-           issue = "27745")]
+           issue = "44930")]
 pub use core::ffi::VaList;
 
 mod c_str;
diff --git a/src/libstd/ffi/os_str.rs b/src/libstd/ffi/os_str.rs
index f817689251324..81433832ffc7e 100644
--- a/src/libstd/ffi/os_str.rs
+++ b/src/libstd/ffi/os_str.rs
@@ -24,7 +24,7 @@ use sys_common::{AsInner, IntoInner, FromInner};
 ///
 /// `OsString` and [`OsStr`] bridge this gap by simultaneously representing Rust
 /// and platform-native string values, and in particular allowing a Rust string
-/// to be converted into an "OS" string with no cost if possible.  A consequence
+/// to be converted into an "OS" string with no cost if possible. A consequence
 /// of this is that `OsString` instances are *not* `NUL` terminated; in order
 /// to pass to e.g., Unix system call, you should create a [`CStr`].
 ///
@@ -259,7 +259,7 @@ impl OsString {
     /// already sufficient.
     ///
     /// Note that the allocator may give the collection more space than it
-    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// requests. Therefore, capacity can not be relied upon to be precisely
     /// minimal. Prefer reserve if future insertions are expected.
     ///
     /// # Examples
@@ -778,10 +778,10 @@ impl Default for Box<OsStr> {
 }
 
 #[stable(feature = "osstring_default", since = "1.9.0")]
-impl<'a> Default for &'a OsStr {
+impl Default for &OsStr {
     /// Creates an empty `OsStr`.
     #[inline]
-    fn default() -> &'a OsStr {
+    fn default() -> Self {
         OsStr::new("")
     }
 }
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index 119b3f7f9f296..79b5686faac60 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -25,7 +25,7 @@ use time::SystemTime;
 ///
 /// # Examples
 ///
-/// Create a new file and write bytes to it:
+/// Creates a new file and write bytes to it:
 ///
 /// ```no_run
 /// use std::fs::File;
@@ -222,7 +222,7 @@ fn initial_buffer_size(file: &File) -> usize {
 /// Read the entire contents of a file into a bytes vector.
 ///
 /// This is a convenience function for using [`File::open`] and [`read_to_end`]
-/// with fewer imports and without an intermediate variable.  It pre-allocates a
+/// with fewer imports and without an intermediate variable. It pre-allocates a
 /// buffer based on the file size when available, so it is generally faster than
 /// reading into a vector created with `Vec::new()`.
 ///
@@ -254,16 +254,19 @@ fn initial_buffer_size(file: &File) -> usize {
 /// ```
 #[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
 pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
-    let mut file = File::open(path)?;
-    let mut bytes = Vec::with_capacity(initial_buffer_size(&file));
-    file.read_to_end(&mut bytes)?;
-    Ok(bytes)
+    fn inner(path: &Path) -> io::Result<Vec<u8>> {
+        let mut file = File::open(path)?;
+        let mut bytes = Vec::with_capacity(initial_buffer_size(&file));
+        file.read_to_end(&mut bytes)?;
+        Ok(bytes)
+    }
+    inner(path.as_ref())
 }
 
 /// Read the entire contents of a file into a string.
 ///
 /// This is a convenience function for using [`File::open`] and [`read_to_string`]
-/// with fewer imports and without an intermediate variable.  It pre-allocates a
+/// with fewer imports and without an intermediate variable. It pre-allocates a
 /// buffer based on the file size when available, so it is generally faster than
 /// reading into a string created with `String::new()`.
 ///
@@ -296,10 +299,13 @@ pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
 /// ```
 #[stable(feature = "fs_read_write", since = "1.26.0")]
 pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
-    let mut file = File::open(path)?;
-    let mut string = String::with_capacity(initial_buffer_size(&file));
-    file.read_to_string(&mut string)?;
-    Ok(string)
+    fn inner(path: &Path) -> io::Result<String> {
+        let mut file = File::open(path)?;
+        let mut string = String::with_capacity(initial_buffer_size(&file));
+        file.read_to_string(&mut string)?;
+        Ok(string)
+    }
+    inner(path.as_ref())
 }
 
 /// Write a slice as the entire contents of a file.
@@ -326,7 +332,10 @@ pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
 /// ```
 #[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
 pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> io::Result<()> {
-    File::create(path)?.write_all(contents.as_ref())
+    fn inner(path: &Path, contents: &[u8]) -> io::Result<()> {
+        File::create(path)?.write_all(contents)
+    }
+    inner(path.as_ref(), contents.as_ref())
 }
 
 impl File {
@@ -488,13 +497,13 @@ impl File {
         self.inner.file_attr().map(Metadata)
     }
 
-    /// Create a new `File` instance that shares the same underlying file handle
+    /// Creates a new `File` instance that shares the same underlying file handle
     /// as the existing `File` instance. Reads, writes, and seeks will affect
     /// both `File` instances simultaneously.
     ///
     /// # Examples
     ///
-    /// Create two handles for a file named `foo.txt`:
+    /// Creates two handles for a file named `foo.txt`:
     ///
     /// ```no_run
     /// use std::fs::File;
@@ -618,7 +627,7 @@ impl Seek for File {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Read for &'a File {
+impl Read for &File {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
@@ -629,14 +638,14 @@ impl<'a> Read for &'a File {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for &'a File {
+impl Write for &File {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.write(buf)
     }
     fn flush(&mut self) -> io::Result<()> { self.inner.flush() }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Seek for &'a File {
+impl Seek for &File {
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
         self.inner.seek(pos)
     }
@@ -896,7 +905,7 @@ impl Metadata {
         FileType(self.0.file_type())
     }
 
-    /// Returns whether this metadata is for a directory. The
+    /// Returns `true` if this metadata is for a directory. The
     /// result is mutually exclusive to the result of
     /// [`is_file`], and will be false for symlink metadata
     /// obtained from [`symlink_metadata`].
@@ -919,7 +928,7 @@ impl Metadata {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn is_dir(&self) -> bool { self.file_type().is_dir() }
 
-    /// Returns whether this metadata is for a regular file. The
+    /// Returns `true` if this metadata is for a regular file. The
     /// result is mutually exclusive to the result of
     /// [`is_dir`], and will be false for symlink metadata
     /// obtained from [`symlink_metadata`].
@@ -1096,7 +1105,7 @@ impl AsInner<fs_imp::FileAttr> for Metadata {
 }
 
 impl Permissions {
-    /// Returns whether these permissions describe a readonly (unwritable) file.
+    /// Returns `true` if these permissions describe a readonly (unwritable) file.
     ///
     /// # Examples
     ///
@@ -1121,7 +1130,9 @@ impl Permissions {
     /// writing.
     ///
     /// This operation does **not** modify the filesystem. To modify the
-    /// filesystem use the `fs::set_permissions` function.
+    /// filesystem use the [`fs::set_permissions`] function.
+    ///
+    /// [`fs::set_permissions`]: fn.set_permissions.html
     ///
     /// # Examples
     ///
@@ -1150,7 +1161,7 @@ impl Permissions {
 }
 
 impl FileType {
-    /// Test whether this file type represents a directory. The
+    /// Tests whether this file type represents a directory. The
     /// result is mutually exclusive to the results of
     /// [`is_file`] and [`is_symlink`]; only zero or one of these
     /// tests may pass.
@@ -1174,7 +1185,7 @@ impl FileType {
     #[stable(feature = "file_type", since = "1.1.0")]
     pub fn is_dir(&self) -> bool { self.0.is_dir() }
 
-    /// Test whether this file type represents a regular file.
+    /// Tests whether this file type represents a regular file.
     /// The result is  mutually exclusive to the results of
     /// [`is_dir`] and [`is_symlink`]; only zero or one of these
     /// tests may pass.
@@ -1198,7 +1209,7 @@ impl FileType {
     #[stable(feature = "file_type", since = "1.1.0")]
     pub fn is_file(&self) -> bool { self.0.is_file() }
 
-    /// Test whether this file type represents a symbolic link.
+    /// Tests whether this file type represents a symbolic link.
     /// The result is mutually exclusive to the results of
     /// [`is_dir`] and [`is_file`]; only zero or one of these
     /// tests may pass.
@@ -1207,7 +1218,7 @@ impl FileType {
     /// with the [`fs::symlink_metadata`] function and not the
     /// [`fs::metadata`] function. The [`fs::metadata`] function
     /// follows symbolic links, so [`is_symlink`] would always
-    /// return false for the target file.
+    /// return `false` for the target file.
     ///
     /// [`Metadata`]: struct.Metadata.html
     /// [`fs::metadata`]: fn.metadata.html
@@ -1288,7 +1299,7 @@ impl DirEntry {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn path(&self) -> PathBuf { self.0.path() }
 
-    /// Return the metadata for the file that this entry points at.
+    /// Returns the metadata for the file that this entry points at.
     ///
     /// This function will not traverse symlinks if this entry points at a
     /// symlink.
@@ -1323,7 +1334,7 @@ impl DirEntry {
         self.0.metadata().map(Metadata)
     }
 
-    /// Return the file type for the file that this entry points at.
+    /// Returns the file type for the file that this entry points at.
     ///
     /// This function will not traverse symlinks if this entry points at a
     /// symlink.
@@ -1639,10 +1650,15 @@ pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> io::Result<(
 ///
 /// The `dst` path will be a symbolic link pointing to the `src` path.
 /// On Windows, this will be a file symlink, not a directory symlink;
-/// for this reason, the platform-specific `std::os::unix::fs::symlink`
-/// and `std::os::windows::fs::{symlink_file, symlink_dir}` should be
+/// for this reason, the platform-specific [`std::os::unix::fs::symlink`]
+/// and [`std::os::windows::fs::symlink_file`] or [`symlink_dir`] should be
 /// used instead to make the intent explicit.
 ///
+/// [`std::os::unix::fs::symlink`]: ../os/unix/fs/fn.symlink.html
+/// [`std::os::windows::fs::symlink_file`]: ../os/windows/fs/fn.symlink_file.html
+/// [`symlink_dir`]: ../os/windows/fs/fn.symlink_dir.html
+///
+///
 /// # Examples
 ///
 /// ```no_run
@@ -1795,7 +1811,7 @@ pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 /// * If any directory in the path specified by `path`
 /// does not already exist and it could not be created otherwise. The specific
 /// error conditions for when a directory is being created (after it is
-/// determined to not exist) are outlined by `fs::create_dir`.
+/// determined to not exist) are outlined by [`fs::create_dir`].
 ///
 /// Notable exception is made for situations where any of the directories
 /// specified in the `path` could not be created as it was being created concurrently.
@@ -1803,6 +1819,8 @@ pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 /// concurrently from multiple threads or processes is guaranteed not to fail
 /// due to a race condition with itself.
 ///
+/// [`fs::create_dir`]: fn.create_dir.html
+///
 /// # Examples
 ///
 /// ```no_run
@@ -1868,7 +1886,10 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///
 /// # Errors
 ///
-/// See `file::remove_file` and `fs::remove_dir`.
+/// See [`fs::remove_file`] and [`fs::remove_dir`].
+///
+/// [`fs::remove_file`]:  fn.remove_file.html
+/// [`fs::remove_dir`]: fn.remove_dir.html
 ///
 /// # Examples
 ///
@@ -2013,7 +2034,7 @@ impl DirBuilder {
         self
     }
 
-    /// Create the specified directory with the options configured in this
+    /// Creates the specified directory with the options configured in this
     /// builder.
     ///
     /// It is considered an error if the directory already exists unless
diff --git a/src/libstd/future.rs b/src/libstd/future.rs
index a7b9895177fe5..aa784746122db 100644
--- a/src/libstd/future.rs
+++ b/src/libstd/future.rs
@@ -5,13 +5,13 @@ use core::marker::Unpin;
 use core::pin::Pin;
 use core::option::Option;
 use core::ptr::NonNull;
-use core::task::{LocalWaker, Poll};
+use core::task::{Waker, Poll};
 use core::ops::{Drop, Generator, GeneratorState};
 
 #[doc(inline)]
 pub use core::future::*;
 
-/// Wrap a future in a generator.
+/// Wrap a generator in a future.
 ///
 /// This function returns a `GenFuture` underneath, but hides it in `impl Trait` to give
 /// better error messages (`impl Future` rather than `GenFuture<[closure.....]>`).
@@ -32,8 +32,10 @@ impl<T: Generator<Yield = ()>> !Unpin for GenFuture<T> {}
 #[unstable(feature = "gen_future", issue = "50547")]
 impl<T: Generator<Yield = ()>> Future for GenFuture<T> {
     type Output = T::Return;
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        set_task_waker(lw, || match unsafe { Pin::get_unchecked_mut(self).0.resume() } {
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        // Safe because we're !Unpin + !Drop mapping to a ?Unpin value
+        let gen = unsafe { Pin::map_unchecked_mut(self, |s| &mut s.0) };
+        set_task_waker(waker, || match gen.resume() {
             GeneratorState::Yielded(()) => Poll::Pending,
             GeneratorState::Complete(x) => Poll::Ready(x),
         })
@@ -41,10 +43,10 @@ impl<T: Generator<Yield = ()>> Future for GenFuture<T> {
 }
 
 thread_local! {
-    static TLS_WAKER: Cell<Option<NonNull<LocalWaker>>> = Cell::new(None);
+    static TLS_WAKER: Cell<Option<NonNull<Waker>>> = Cell::new(None);
 }
 
-struct SetOnDrop(Option<NonNull<LocalWaker>>);
+struct SetOnDrop(Option<NonNull<Waker>>);
 
 impl Drop for SetOnDrop {
     fn drop(&mut self) {
@@ -56,12 +58,12 @@ impl Drop for SetOnDrop {
 
 #[unstable(feature = "gen_future", issue = "50547")]
 /// Sets the thread-local task context used by async/await futures.
-pub fn set_task_waker<F, R>(lw: &LocalWaker, f: F) -> R
+pub fn set_task_waker<F, R>(waker: &Waker, f: F) -> R
 where
     F: FnOnce() -> R
 {
     let old_waker = TLS_WAKER.with(|tls_waker| {
-        tls_waker.replace(Some(NonNull::from(lw)))
+        tls_waker.replace(Some(NonNull::from(waker)))
     });
     let _reset_waker = SetOnDrop(old_waker);
     f()
@@ -76,7 +78,7 @@ where
 /// retrieved by a surrounding call to get_task_waker.
 pub fn get_task_waker<F, R>(f: F) -> R
 where
-    F: FnOnce(&LocalWaker) -> R
+    F: FnOnce(&Waker) -> R
 {
     let waker_ptr = TLS_WAKER.with(|tls_waker| {
         // Clear the entry so that nested `get_task_waker` calls
@@ -86,7 +88,7 @@ where
     let _reset_waker = SetOnDrop(waker_ptr);
 
     let waker_ptr = waker_ptr.expect(
-        "TLS LocalWaker not set. This is a rustc bug. \
+        "TLS Waker not set. This is a rustc bug. \
         Please file an issue on https://github.com/rust-lang/rust.");
     unsafe { f(waker_ptr.as_ref()) }
 }
@@ -97,5 +99,5 @@ pub fn poll_with_tls_waker<F>(f: Pin<&mut F>) -> Poll<F::Output>
 where
     F: Future
 {
-    get_task_waker(|lw| F::poll(f, lw))
+    get_task_waker(|waker| F::poll(f, waker))
 }
diff --git a/src/libstd/io/buffered.rs b/src/libstd/io/buffered.rs
index 056aa7c0c4263..0c1d155a91688 100644
--- a/src/libstd/io/buffered.rs
+++ b/src/libstd/io/buffered.rs
@@ -16,9 +16,9 @@ use memchr;
 /// the underlying [`Read`] and maintains an in-memory buffer of the results.
 ///
 /// `BufReader` can improve the speed of programs that make *small* and
-/// *repeated* read calls to the same file or network socket.  It does not
+/// *repeated* read calls to the same file or network socket. It does not
 /// help when reading very large amounts at once, or reading just one or a few
-/// times.  It also provides no advantage when reading from a source that is
+/// times. It also provides no advantage when reading from a source that is
 /// already in memory, like a `Vec<u8>`.
 ///
 /// [`Read`]: ../../std/io/trait.Read.html
@@ -331,9 +331,9 @@ impl<R: Seek> Seek for BufReader<R> {
 /// writer in large, infrequent batches.
 ///
 /// `BufWriter` can improve the speed of programs that make *small* and
-/// *repeated* write calls to the same file or network socket.  It does not
+/// *repeated* write calls to the same file or network socket. It does not
 /// help when writing very large amounts at once, or writing just one or a few
-/// times.  It also provides no advantage when writing to a destination that is
+/// times. It also provides no advantage when writing to a destination that is
 /// in memory, like a `Vec<u8>`.
 ///
 /// When the `BufWriter` is dropped, the contents of its buffer will be written
@@ -1174,7 +1174,7 @@ mod tests {
         // Issue #32085
         struct FailFlushWriter<'a>(&'a mut Vec<u8>);
 
-        impl<'a> Write for FailFlushWriter<'a> {
+        impl Write for FailFlushWriter<'_> {
             fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
                 self.0.extend_from_slice(buf);
                 Ok(buf.len())
diff --git a/src/libstd/io/cursor.rs b/src/libstd/io/cursor.rs
index b205f7888389f..758d856867291 100644
--- a/src/libstd/io/cursor.rs
+++ b/src/libstd/io/cursor.rs
@@ -279,7 +279,7 @@ fn vec_write(pos_mut: &mut u64, vec: &mut Vec<u8>, buf: &[u8]) -> io::Result<usi
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for Cursor<&'a mut [u8]> {
+impl Write for Cursor<&mut [u8]> {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         slice_write(&mut self.pos, self.inner, buf)
@@ -288,7 +288,7 @@ impl<'a> Write for Cursor<&'a mut [u8]> {
 }
 
 #[stable(feature = "cursor_mut_vec", since = "1.25.0")]
-impl<'a> Write for Cursor<&'a mut Vec<u8>> {
+impl Write for Cursor<&mut Vec<u8>> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         vec_write(&mut self.pos, self.inner, buf)
     }
diff --git a/src/libstd/io/impls.rs b/src/libstd/io/impls.rs
index ec75a87aec34f..2577b284714ab 100644
--- a/src/libstd/io/impls.rs
+++ b/src/libstd/io/impls.rs
@@ -7,7 +7,7 @@ use mem;
 // Forwarding implementations
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, R: Read + ?Sized> Read for &'a mut R {
+impl<R: Read + ?Sized> Read for &mut R {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         (**self).read(buf)
@@ -34,7 +34,7 @@ impl<'a, R: Read + ?Sized> Read for &'a mut R {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, W: Write + ?Sized> Write for &'a mut W {
+impl<W: Write + ?Sized> Write for &mut W {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> { (**self).write(buf) }
 
@@ -52,12 +52,12 @@ impl<'a, W: Write + ?Sized> Write for &'a mut W {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, S: Seek + ?Sized> Seek for &'a mut S {
+impl<S: Seek + ?Sized> Seek for &mut S {
     #[inline]
     fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> { (**self).seek(pos) }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: BufRead + ?Sized> BufRead for &'a mut B {
+impl<B: BufRead + ?Sized> BufRead for &mut B {
     #[inline]
     fn fill_buf(&mut self) -> io::Result<&[u8]> { (**self).fill_buf() }
 
@@ -152,7 +152,7 @@ impl<B: BufRead + ?Sized> BufRead for Box<B> {
 /// Note that reading updates the slice to point to the yet unread part.
 /// The slice will be empty when EOF is reached.
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Read for &'a [u8] {
+impl Read for &[u8] {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         let amt = cmp::min(buf.len(), self.len());
@@ -207,7 +207,7 @@ impl<'a> Read for &'a [u8] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> BufRead for &'a [u8] {
+impl BufRead for &[u8] {
     #[inline]
     fn fill_buf(&mut self) -> io::Result<&[u8]> { Ok(*self) }
 
@@ -221,7 +221,7 @@ impl<'a> BufRead for &'a [u8] {
 /// Note that writing updates the slice to point to the yet unwritten part.
 /// The slice will be empty when it has been completely overwritten.
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for &'a mut [u8] {
+impl Write for &mut [u8] {
     #[inline]
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
         let amt = cmp::min(data.len(), self.len());
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 28a6fbd48cf09..b634ea43e34e5 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -299,7 +299,7 @@ const DEFAULT_BUF_SIZE: usize = ::sys_common::io::DEFAULT_BUF_SIZE;
 
 struct Guard<'a> { buf: &'a mut Vec<u8>, len: usize }
 
-impl<'a> Drop for Guard<'a> {
+impl Drop for Guard<'_> {
     fn drop(&mut self) {
         unsafe { self.buf.set_len(self.len); }
     }
@@ -1114,7 +1114,7 @@ pub trait Write {
             error: Result<()>,
         }
 
-        impl<'a, T: Write + ?Sized> fmt::Write for Adaptor<'a, T> {
+        impl<T: Write + ?Sized> fmt::Write for Adaptor<'_, T> {
             fn write_str(&mut self, s: &str) -> fmt::Result {
                 match self.inner.write_all(s.as_bytes()) {
                     Ok(()) => Ok(()),
@@ -1219,11 +1219,11 @@ pub trait Seek {
 #[derive(Copy, PartialEq, Eq, Clone, Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub enum SeekFrom {
-    /// Set the offset to the provided number of bytes.
+    /// Sets the offset to the provided number of bytes.
     #[stable(feature = "rust1", since = "1.0.0")]
     Start(#[stable(feature = "rust1", since = "1.0.0")] u64),
 
-    /// Set the offset to the size of this object plus the specified number of
+    /// Sets the offset to the size of this object plus the specified number of
     /// bytes.
     ///
     /// It is possible to seek beyond the end of an object, but it's an error to
@@ -1231,7 +1231,7 @@ pub enum SeekFrom {
     #[stable(feature = "rust1", since = "1.0.0")]
     End(#[stable(feature = "rust1", since = "1.0.0")] i64),
 
-    /// Set the offset to the current position plus the specified number of
+    /// Sets the offset to the current position plus the specified number of
     /// bytes.
     ///
     /// It is possible to seek beyond the end of an object, but it's an error to
diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index d249469323063..0324568e6fb52 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -131,6 +131,11 @@ fn handle_ebadf<T>(r: io::Result<T>, default: T) -> io::Result<T> {
 ///
 /// [`io::stdin`]: fn.stdin.html
 /// [`BufRead`]: trait.BufRead.html
+///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return
+/// an error.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Stdin {
     inner: Arc<Mutex<BufReader<Maybe<StdinRaw>>>>,
@@ -144,6 +149,11 @@ pub struct Stdin {
 /// [`Read`]: trait.Read.html
 /// [`BufRead`]: trait.BufRead.html
 /// [`Stdin::lock`]: struct.Stdin.html#method.lock
+///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return
+/// an error.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct StdinLock<'a> {
     inner: MutexGuard<'a, BufReader<Maybe<StdinRaw>>>,
@@ -157,6 +167,11 @@ pub struct StdinLock<'a> {
 ///
 /// [lock]: struct.Stdin.html#method.lock
 ///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to read bytes that are not valid UTF-8 will return
+/// an error.
+///
 /// # Examples
 ///
 /// Using implicit synchronization:
@@ -297,7 +312,7 @@ impl Read for Stdin {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Read for StdinLock<'a> {
+impl Read for StdinLock<'_> {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
@@ -308,13 +323,13 @@ impl<'a> Read for StdinLock<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> BufRead for StdinLock<'a> {
+impl BufRead for StdinLock<'_> {
     fn fill_buf(&mut self) -> io::Result<&[u8]> { self.inner.fill_buf() }
     fn consume(&mut self, n: usize) { self.inner.consume(n) }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a> fmt::Debug for StdinLock<'a> {
+impl fmt::Debug for StdinLock<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.pad("StdinLock { .. }")
     }
@@ -328,6 +343,11 @@ impl<'a> fmt::Debug for StdinLock<'a> {
 ///
 /// Created by the [`io::stdout`] method.
 ///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
+///
 /// [`lock`]: #method.lock
 /// [`io::stdout`]: fn.stdout.html
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -343,6 +363,11 @@ pub struct Stdout {
 /// This handle implements the [`Write`] trait, and is constructed via
 /// the [`Stdout::lock`] method.
 ///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
+///
 /// [`Write`]: trait.Write.html
 /// [`Stdout::lock`]: struct.Stdout.html#method.lock
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -358,6 +383,11 @@ pub struct StdoutLock<'a> {
 ///
 /// [Stdout::lock]: struct.Stdout.html#method.lock
 ///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
+///
 /// # Examples
 ///
 /// Using implicit synchronization:
@@ -455,7 +485,7 @@ impl Write for Stdout {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for StdoutLock<'a> {
+impl Write for StdoutLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.borrow_mut().write(buf)
     }
@@ -465,7 +495,7 @@ impl<'a> Write for StdoutLock<'a> {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a> fmt::Debug for StdoutLock<'a> {
+impl fmt::Debug for StdoutLock<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.pad("StdoutLock { .. }")
     }
@@ -476,6 +506,11 @@ impl<'a> fmt::Debug for StdoutLock<'a> {
 /// For more information, see the [`io::stderr`] method.
 ///
 /// [`io::stderr`]: fn.stderr.html
+///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Stderr {
     inner: Arc<ReentrantMutex<RefCell<Maybe<StderrRaw>>>>,
@@ -487,6 +522,11 @@ pub struct Stderr {
 /// the [`Stderr::lock`] method.
 ///
 /// [`Stderr::lock`]: struct.Stderr.html#method.lock
+///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct StderrLock<'a> {
     inner: ReentrantMutexGuard<'a, RefCell<Maybe<StderrRaw>>>,
@@ -496,6 +536,11 @@ pub struct StderrLock<'a> {
 ///
 /// This handle is not buffered.
 ///
+/// ### Note: Windows Portability Consideration
+/// When operating in a console, the Windows implementation of this stream does not support
+/// non-UTF-8 byte sequences. Attempting to write bytes that are not valid UTF-8 will return
+/// an error.
+///
 /// # Examples
 ///
 /// Using implicit synchronization:
@@ -593,7 +638,7 @@ impl Write for Stderr {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for StderrLock<'a> {
+impl Write for StderrLock<'_> {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         self.inner.borrow_mut().write(buf)
     }
@@ -603,7 +648,7 @@ impl<'a> Write for StderrLock<'a> {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a> fmt::Debug for StderrLock<'a> {
+impl fmt::Debug for StderrLock<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.pad("StderrLock { .. }")
     }
diff --git a/src/libstd/keyword_docs.rs b/src/libstd/keyword_docs.rs
index a7ecee2d82203..bef6bc9266197 100644
--- a/src/libstd/keyword_docs.rs
+++ b/src/libstd/keyword_docs.rs
@@ -260,7 +260,7 @@ mod extern_keyword { }
 /// }
 ///
 /// fn generic_where<T>(x: T) -> T
-///     where T: std::ops::Add<Output=T> + Copy
+///     where T: std::ops::Add<Output = T> + Copy
 /// {
 ///     x + x + x
 /// }
@@ -289,7 +289,7 @@ mod fn_keyword { }
 /// `for` is primarily used in for-in-loops, but it has a few other pieces of syntactic uses such as
 /// `impl Trait for Type` (see [`impl`] for more info on that). for-in-loops, or to be more
 /// precise, iterator loops, are a simple syntactic sugar over an exceedingly common practice
-/// within Rust, which is to loop over an iterator until that iterator returns None (or `break`
+/// within Rust, which is to loop over an iterator until that iterator returns `None` (or `break`
 /// is called).
 ///
 /// ```rust
@@ -627,7 +627,7 @@ mod loop_keyword { }
 /// directly accessed and modified.
 ///
 /// Tuple structs are similar to regular structs, but its fields have no names. They are used like
-/// tuples, with deconstruction possible via `let TupleStruct(x, y) = foo;` syntax.  For accessing
+/// tuples, with deconstruction possible via `let TupleStruct(x, y) = foo;` syntax. For accessing
 /// individual variables, the same syntax is used as with regular tuples, namely `foo.0`, `foo.1`,
 /// etc, starting at zero.
 ///
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 41f1ac867ed15..6dd3a6cc0fdbd 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -7,11 +7,9 @@
 //! primitives](#primitives), [standard macros](#macros), [I/O] and
 //! [multithreading], among [many other things][other].
 //!
-//! `std` is available to all Rust crates by default, just as if each one
-//! contained an `extern crate std;` import at the [crate root]. Therefore the
+//! `std` is available to all Rust crates by default. Therefore, the
 //! standard library can be accessed in [`use`] statements through the path
-//! `std`, as in [`use std::env`], or in expressions through the absolute path
-//! `::std`, as in [`::std::env::args`].
+//! `std`, as in [`use std::env`].
 //!
 //! # How to read this documentation
 //!
@@ -157,7 +155,6 @@
 //! [TCP]: net/struct.TcpStream.html
 //! [The Rust Prelude]: prelude/index.html
 //! [UDP]: net/struct.UdpSocket.html
-//! [`::std::env::args`]: env/fn.args.html
 //! [`Arc`]: sync/struct.Arc.html
 //! [owned slice]: boxed/index.html
 //! [`Cell`]: cell/struct.Cell.html
@@ -191,7 +188,6 @@
 //! [`thread`]: thread/index.html
 //! [`use std::env`]: env/index.html
 //! [`use`]: ../book/ch07-02-modules-and-use-to-control-scope-and-privacy.html#the-use-keyword-to-bring-paths-into-a-scope
-//! [crate root]: ../book/ch07-01-packages-and-crates-for-making-libraries-and-executables.html
 //! [crates.io]: https://crates.io
 //! [deref-coercions]: ../book/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods
 //! [files]: fs/struct.File.html
@@ -200,9 +196,7 @@
 //! [primitive types]: ../book/ch03-02-data-types.html
 
 #![stable(feature = "rust1", since = "1.0.0")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
        test(no_crate_inject, attr(deny(warnings))),
@@ -221,16 +215,22 @@
 // std may use features in a platform-specific way
 #![allow(unused_features)]
 
+#![cfg_attr(test, feature(test, update_panic_count))]
+#![cfg_attr(all(target_vendor = "fortanix", target_env = "sgx"),
+            feature(global_asm, range_contains, slice_index_methods,
+                    decl_macro, coerce_unsized, sgx_platform, ptr_wrapping_offset_from))]
+
 // std is implemented with unstable features, many of which are internal
 // compiler details that will never be stable
-#![cfg_attr(test, feature(test, update_panic_count))]
-#![feature(alloc)]
+// NB: the following list is sorted to minimize merge conflicts.
+#![feature(align_offset)]
 #![feature(alloc_error_handler)]
+#![feature(alloc_layout_extra)]
+#![feature(alloc)]
 #![feature(allocator_api)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
 #![feature(allow_internal_unstable)]
-#![feature(align_offset)]
 #![feature(arbitrary_self_types)]
 #![feature(array_error_internals)]
 #![feature(asm)]
@@ -238,24 +238,29 @@
 #![feature(c_variadic)]
 #![feature(cfg_target_has_atomic)]
 #![feature(cfg_target_thread_local)]
-#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(char_error_internals)]
+#![feature(checked_duration_since)]
 #![feature(compiler_builtins_lib)]
 #![feature(concat_idents)]
-#![cfg_attr(stage0, feature(const_int_ops))]
-#![cfg_attr(stage0, feature(const_ip))]
-#![feature(const_raw_ptr_deref)]
 #![feature(const_cstr_unchecked)]
+#![feature(const_raw_ptr_deref)]
 #![feature(core_intrinsics)]
+#![feature(doc_alias)]
+#![feature(doc_cfg)]
+#![feature(doc_keyword)]
+#![feature(doc_masked)]
+#![feature(doc_spotlight)]
 #![feature(dropck_eyepatch)]
 #![feature(duration_constants)]
 #![feature(exact_size_is_empty)]
+#![feature(exhaustive_patterns)]
 #![feature(external_doc)]
 #![feature(fixed_size_array)]
 #![feature(fn_traits)]
 #![feature(fnbox)]
 #![feature(futures_api)]
 #![feature(generator_trait)]
+#![feature(hash_raw_entry)]
 #![feature(hashmap_internals)]
 #![feature(int_error_internals)]
 #![feature(integer_atomics)]
@@ -263,30 +268,32 @@
 #![feature(libc)]
 #![feature(link_args)]
 #![feature(linkage)]
+#![feature(maybe_uninit)]
 #![feature(needs_panic_runtime)]
 #![feature(never_type)]
 #![feature(nll)]
-#![feature(exhaustive_patterns)]
+#![feature(non_exhaustive)]
 #![feature(on_unimplemented)]
 #![feature(optin_builtin_traits)]
+#![feature(panic_info_message)]
 #![feature(panic_internals)]
 #![feature(panic_unwind)]
 #![feature(prelude_import)]
 #![feature(ptr_internals)]
 #![feature(raw)]
-#![feature(hash_raw_entry)]
+#![feature(renamed_spin_loop)]
 #![feature(rustc_attrs)]
 #![feature(rustc_const_unstable)]
-#![feature(std_internals)]
-#![feature(stdsimd)]
+#![feature(rustc_private)]
 #![feature(shrink_to)]
 #![feature(slice_concat_ext)]
 #![feature(slice_internals)]
 #![feature(slice_patterns)]
 #![feature(staged_api)]
+#![feature(std_internals)]
+#![feature(stdsimd)]
 #![feature(stmt_expr_attributes)]
 #![feature(str_internals)]
-#![feature(rustc_private)]
 #![feature(thread_local)]
 #![feature(toowned_clone_into)]
 #![feature(try_from)]
@@ -294,18 +301,7 @@
 #![feature(unboxed_closures)]
 #![feature(untagged_unions)]
 #![feature(unwind_attributes)]
-#![feature(doc_cfg)]
-#![feature(doc_masked)]
-#![feature(doc_spotlight)]
-#![feature(doc_alias)]
-#![feature(doc_keyword)]
-#![feature(panic_info_message)]
-#![feature(non_exhaustive)]
-#![feature(alloc_layout_extra)]
-#![feature(maybe_uninit)]
-#![cfg_attr(all(target_vendor = "fortanix", target_env = "sgx"),
-            feature(global_asm, range_contains, slice_index_methods,
-                    decl_macro, coerce_unsized, sgx_platform, ptr_wrapping_offset_from))]
+// NB: the above list is sorted to minimize merge conflicts.
 
 #![default_lib_allocator]
 
@@ -349,9 +345,6 @@ extern crate backtrace_sys;
 #[cfg(test)] extern crate std as realstd;
 
 #[cfg(all(target_vendor = "fortanix", target_env = "sgx"))]
-#[macro_use]
-#[allow(unused_imports)] // FIXME: without `#[macro_use]`, get error: “cannot
-                         // determine resolution for the macro `usercalls_asm`”
 extern crate fortanix_sgx_abi;
 
 // The standard macros that are not built-in to the compiler.
@@ -364,6 +357,9 @@ pub mod prelude;
 // Public module declarations and re-exports
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::any;
+#[stable(feature = "simd_arch", since = "1.27.0")]
+#[doc(no_inline)]
+pub use core::arch;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use core::cell;
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -471,8 +467,6 @@ pub mod task {
     //! Types and Traits for working with asynchronous tasks.
     #[doc(inline)]
     pub use core::task::*;
-    #[doc(inline)]
-    pub use alloc_crate::task::*;
 }
 
 #[unstable(feature = "futures_api",
@@ -495,29 +489,22 @@ mod memchr;
 // compiler
 pub mod rt;
 
-// Pull in the `stdsimd` crate directly into libstd. This is the same as
-// libcore's arch/simd modules where the source of truth here is in a different
-// repository, but we pull things in here manually to get it into libstd.
+// Pull in the `std_detect` crate directly into libstd. The contents of
+// `std_detect` are in a different repository: rust-lang-nursery/stdsimd.
 //
-// Note that the #[cfg] here is intended to do two things. First it allows us to
-// change the rustc implementation of intrinsics in stage0 by not compiling simd
-// intrinsics in stage0. Next it doesn't compile anything in test mode as
-// stdsimd has tons of its own tests which we don't want to run.
-#[path = "../stdsimd/stdsimd/mod.rs"]
+// `std_detect` depends on libstd, but the contents of this module are
+// set up in such a way that directly pulling it here works such that the
+// crate uses the this crate as its libstd.
+#[path = "../stdsimd/crates/std_detect/src/mod.rs"]
 #[allow(missing_debug_implementations, missing_docs, dead_code)]
 #[unstable(feature = "stdsimd", issue = "48556")]
 #[cfg(not(test))]
-mod stdsimd;
-
-// A "fake" module needed by the `stdsimd` module to compile, not actually
-// exported though.
-mod coresimd {
-    pub use core::arch;
-}
+mod std_detect;
 
-#[stable(feature = "simd_arch", since = "1.27.0")]
+#[doc(hidden)]
+#[unstable(feature = "stdsimd", issue = "48556")]
 #[cfg(not(test))]
-pub use stdsimd::arch;
+pub use std_detect::detect;
 
 // Include a number of private modules that exist solely to provide
 // the rustdoc documentation for primitive types. Using `include!`
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index b87257188df10..b9204d27f5392 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -8,11 +8,11 @@
 ///
 /// This allows a program to terminate immediately and provide feedback
 /// to the caller of the program. `panic!` should be used when a program reaches
-/// an unrecoverable problem.
+/// an unrecoverable state.
 ///
 /// This macro is the perfect way to assert conditions in example code and in
-/// tests.  `panic!` is closely tied with the `unwrap` method of both [`Option`]
-/// and [`Result`][runwrap] enums.  Both implementations call `panic!` when they are set
+/// tests. `panic!` is closely tied with the `unwrap` method of both [`Option`]
+/// and [`Result`][runwrap] enums. Both implementations call `panic!` when they are set
 /// to None or Err variants.
 ///
 /// This macro is used to inject panic into a Rust thread, causing the thread to
@@ -21,7 +21,7 @@
 /// is transmitted.
 ///
 /// [`Result`] enum is often a better solution for recovering from errors than
-/// using the `panic!` macro.  This macro should be used to avoid proceeding using
+/// using the `panic!` macro. This macro should be used to avoid proceeding using
 /// incorrect values, such as from external sources. Detailed information about
 /// error handling is found in the [book].
 ///
@@ -53,7 +53,8 @@
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(__rust_unstable_column, libstd_sys_internals))]
 macro_rules! panic {
     () => ({
         panic!("explicit panic")
@@ -79,7 +80,7 @@ macro_rules! panic {
 /// necessary to use [`io::stdout().flush()`][flush] to ensure the output is emitted
 /// immediately.
 ///
-/// Use `print!` only for the primary output of your program.  Use
+/// Use `print!` only for the primary output of your program. Use
 /// [`eprint!`] instead to print error and progress messages.
 ///
 /// [`println!`]: ../std/macro.println.html
@@ -111,7 +112,8 @@ macro_rules! panic {
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(print_internals))]
 macro_rules! print {
     ($($arg:tt)*) => ($crate::io::_print(format_args!($($arg)*)));
 }
@@ -124,7 +126,7 @@ macro_rules! print {
 /// Use the [`format!`] syntax to write data to the standard output.
 /// See [`std::fmt`] for more information.
 ///
-/// Use `println!` only for the primary output of your program.  Use
+/// Use `println!` only for the primary output of your program. Use
 /// [`eprintln!`] instead to print error and progress messages.
 ///
 /// [`format!`]: ../std/macro.format.html
@@ -143,7 +145,8 @@ macro_rules! print {
 /// ```
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(print_internals, format_args_nl))]
 macro_rules! println {
     () => (print!("\n"));
     ($($arg:tt)*) => ({
@@ -154,10 +157,10 @@ macro_rules! println {
 /// Macro for printing to the standard error.
 ///
 /// Equivalent to the [`print!`] macro, except that output goes to
-/// [`io::stderr`] instead of `io::stdout`.  See [`print!`] for
+/// [`io::stderr`] instead of `io::stdout`. See [`print!`] for
 /// example usage.
 ///
-/// Use `eprint!` only for error and progress messages.  Use `print!`
+/// Use `eprint!` only for error and progress messages. Use `print!`
 /// instead for the primary output of your program.
 ///
 /// [`io::stderr`]: ../std/io/struct.Stderr.html
@@ -174,7 +177,8 @@ macro_rules! println {
 /// ```
 #[macro_export]
 #[stable(feature = "eprint", since = "1.19.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(print_internals))]
 macro_rules! eprint {
     ($($arg:tt)*) => ($crate::io::_eprint(format_args!($($arg)*)));
 }
@@ -182,10 +186,10 @@ macro_rules! eprint {
 /// Macro for printing to the standard error, with a newline.
 ///
 /// Equivalent to the [`println!`] macro, except that output goes to
-/// [`io::stderr`] instead of `io::stdout`.  See [`println!`] for
+/// [`io::stderr`] instead of `io::stdout`. See [`println!`] for
 /// example usage.
 ///
-/// Use `eprintln!` only for error and progress messages.  Use `println!`
+/// Use `eprintln!` only for error and progress messages. Use `println!`
 /// instead for the primary output of your program.
 ///
 /// [`io::stderr`]: ../std/io/struct.Stderr.html
@@ -202,7 +206,8 @@ macro_rules! eprint {
 /// ```
 #[macro_export]
 #[stable(feature = "eprint", since = "1.19.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(print_internals, format_args_nl))]
 macro_rules! eprintln {
     () => (eprint!("\n"));
     ($($arg:tt)*) => ({
@@ -325,7 +330,8 @@ macro_rules! dbg {
 /// A macro to await on an async call.
 #[macro_export]
 #[unstable(feature = "await_macro", issue = "50547")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(gen_future, generators))]
 #[allow_internal_unsafe]
 macro_rules! await {
     ($e:expr) => { {
@@ -462,16 +468,16 @@ mod builtin {
     /// The core macro for formatted string creation & output.
     ///
     /// This macro functions by taking a formatting string literal containing
-    /// `{}` for each additional argument passed.  `format_args!` prepares the
+    /// `{}` for each additional argument passed. `format_args!` prepares the
     /// additional parameters to ensure the output can be interpreted as a string
-    /// and canonicalizes the arguments into a single type.  Any value that implements
+    /// and canonicalizes the arguments into a single type. Any value that implements
     /// the [`Display`] trait can be passed to `format_args!`, as can any
     /// [`Debug`] implementation be passed to a `{:?}` within the formatting string.
     ///
     /// This macro produces a value of type [`fmt::Arguments`]. This value can be
     /// passed to the macros within [`std::fmt`] for performing useful redirection.
     /// All other formatting macros ([`format!`], [`write!`], [`println!`], etc) are
-    /// proxied through this one.  `format_args!`, unlike its derived macros, avoids
+    /// proxied through this one. `format_args!`, unlike its derived macros, avoids
     /// heap allocations.
     ///
     /// You can use the [`fmt::Arguments`] value that `format_args!` returns
@@ -554,7 +560,7 @@ mod builtin {
     /// If the named environment variable is present at compile time, this will
     /// expand into an expression of type `Option<&'static str>` whose value is
     /// `Some` of the value of the environment variable. If the environment
-    /// variable is not present, then this will expand to `None`.  See
+    /// variable is not present, then this will expand to `None`. See
     /// [`Option<T>`][option] for more information on this type.
     ///
     /// A compile time error is never emitted when using this macro regardless
@@ -904,7 +910,7 @@ mod builtin {
     /// # Custom Messages
     ///
     /// This macro has a second form, where a custom panic message can
-    /// be provided with or without arguments for formatting.  See [`std::fmt`]
+    /// be provided with or without arguments for formatting. See [`std::fmt`]
     /// for syntax for this form.
     ///
     /// [`panic!`]: macro.panic.html
diff --git a/src/libstd/net/addr.rs b/src/libstd/net/addr.rs
index 8ace11276586f..4b60ee8e6dadd 100644
--- a/src/libstd/net/addr.rs
+++ b/src/libstd/net/addr.rs
@@ -510,7 +510,7 @@ impl SocketAddrV6 {
         self.inner.sin6_scope_id
     }
 
-    /// Change the scope ID associated with this socket address.
+    /// Changes the scope ID associated with this socket address.
     ///
     /// See the [`scope_id`] method's documentation for more details.
     ///
@@ -671,7 +671,7 @@ impl hash::Hash for SocketAddrV6 {
 /// [`SocketAddr`] values.
 ///
 /// This trait is used for generic address resolution when constructing network
-/// objects.  By default it is implemented for the following types:
+/// objects. By default it is implemented for the following types:
 ///
 ///  * [`SocketAddr`]: [`to_socket_addrs`] is the identity function.
 ///
@@ -861,7 +861,7 @@ fn resolve_socket_addr(lh: LookupHost) -> io::Result<vec::IntoIter<SocketAddr>>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> ToSocketAddrs for (&'a str, u16) {
+impl ToSocketAddrs for (&str, u16) {
     type Iter = vec::IntoIter<SocketAddr>;
     fn to_socket_addrs(&self) -> io::Result<vec::IntoIter<SocketAddr>> {
         let (host, port) = *self;
@@ -904,7 +904,7 @@ impl<'a> ToSocketAddrs for &'a [SocketAddr] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ToSocketAddrs + ?Sized> ToSocketAddrs for &'a T {
+impl<T: ToSocketAddrs + ?Sized> ToSocketAddrs for &T {
     type Iter = T::Iter;
     fn to_socket_addrs(&self) -> io::Result<T::Iter> {
         (**self).to_socket_addrs()
diff --git a/src/libstd/net/ip.rs b/src/libstd/net/ip.rs
index f98113e0896f7..c856129016814 100644
--- a/src/libstd/net/ip.rs
+++ b/src/libstd/net/ip.rs
@@ -328,8 +328,9 @@ impl Ipv4Addr {
     /// let addr = Ipv4Addr::new(127, 0, 0, 1);
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[cfg_attr(stage0, rustc_const_unstable(feature = "const_ip"))]
     pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Ipv4Addr {
+        // FIXME: should just be u32::from_be_bytes([a, b, c, d]),
+        // once that method is no longer rustc_const_unstable
         Ipv4Addr {
             inner: c::in_addr {
                 s_addr: u32::to_be(
@@ -393,8 +394,8 @@ impl Ipv4Addr {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn octets(&self) -> [u8; 4] {
-        let bits = u32::from_be(self.inner.s_addr);
-        [(bits >> 24) as u8, (bits >> 16) as u8, (bits >> 8) as u8, bits as u8]
+        // This returns the order we want because s_addr is stored in big-endian.
+        self.inner.s_addr.to_ne_bytes()
     }
 
     /// Returns [`true`] for the special 'unspecified' address (0.0.0.0).
@@ -620,9 +621,13 @@ impl Ipv4Addr {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn to_ipv6_compatible(&self) -> Ipv6Addr {
-        Ipv6Addr::new(0, 0, 0, 0, 0, 0,
-                      ((self.octets()[0] as u16) << 8) | self.octets()[1] as u16,
-                      ((self.octets()[2] as u16) << 8) | self.octets()[3] as u16)
+        let octets = self.octets();
+        Ipv6Addr::from([
+            0, 0, 0, 0,
+            0, 0, 0, 0,
+            0, 0, 0, 0,
+            octets[0], octets[1], octets[2], octets[3],
+        ])
     }
 
     /// Converts this address to an IPv4-mapped [IPv6 address].
@@ -641,9 +646,13 @@ impl Ipv4Addr {
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn to_ipv6_mapped(&self) -> Ipv6Addr {
-        Ipv6Addr::new(0, 0, 0, 0, 0, 0xffff,
-                      ((self.octets()[0] as u16) << 8) | self.octets()[1] as u16,
-                      ((self.octets()[2] as u16) << 8) | self.octets()[3] as u16)
+        let octets = self.octets();
+        Ipv6Addr::from([
+            0, 0, 0, 0,
+            0, 0, 0, 0,
+            0, 0, 0xFF, 0xFF,
+            octets[0], octets[1], octets[2], octets[3],
+        ])
     }
 }
 
@@ -774,7 +783,7 @@ impl FromInner<c::in_addr> for Ipv4Addr {
 
 #[stable(feature = "ip_u32", since = "1.1.0")]
 impl From<Ipv4Addr> for u32 {
-    /// Convert an `Ipv4Addr` into a host byte order `u32`.
+    /// Converts an `Ipv4Addr` into a host byte order `u32`.
     ///
     /// # Examples
     ///
@@ -786,13 +795,13 @@ impl From<Ipv4Addr> for u32 {
     /// ```
     fn from(ip: Ipv4Addr) -> u32 {
         let ip = ip.octets();
-        ((ip[0] as u32) << 24) + ((ip[1] as u32) << 16) + ((ip[2] as u32) << 8) + (ip[3] as u32)
+        u32::from_be_bytes(ip)
     }
 }
 
 #[stable(feature = "ip_u32", since = "1.1.0")]
 impl From<u32> for Ipv4Addr {
-    /// Convert a host byte order `u32` into an `Ipv4Addr`.
+    /// Converts a host byte order `u32` into an `Ipv4Addr`.
     ///
     /// # Examples
     ///
@@ -803,7 +812,7 @@ impl From<u32> for Ipv4Addr {
     /// assert_eq!(Ipv4Addr::new(13, 12, 11, 10), addr);
     /// ```
     fn from(ip: u32) -> Ipv4Addr {
-        Ipv4Addr::new((ip >> 24) as u8, (ip >> 16) as u8, (ip >> 8) as u8, ip as u8)
+        Ipv4Addr::from(ip.to_be_bytes())
     }
 }
 
@@ -824,7 +833,7 @@ impl From<[u8; 4]> for Ipv4Addr {
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
 impl From<[u8; 4]> for IpAddr {
-    /// Create an `IpAddr::V4` from a four element byte array.
+    /// Creates an `IpAddr::V4` from a four element byte array.
     ///
     /// # Examples
     ///
@@ -911,14 +920,14 @@ impl Ipv6Addr {
     pub fn segments(&self) -> [u16; 8] {
         let arr = &self.inner.s6_addr;
         [
-            (arr[0] as u16) << 8 | (arr[1] as u16),
-            (arr[2] as u16) << 8 | (arr[3] as u16),
-            (arr[4] as u16) << 8 | (arr[5] as u16),
-            (arr[6] as u16) << 8 | (arr[7] as u16),
-            (arr[8] as u16) << 8 | (arr[9] as u16),
-            (arr[10] as u16) << 8 | (arr[11] as u16),
-            (arr[12] as u16) << 8 | (arr[13] as u16),
-            (arr[14] as u16) << 8 | (arr[15] as u16),
+            u16::from_be_bytes([arr[0], arr[1]]),
+            u16::from_be_bytes([arr[2], arr[3]]),
+            u16::from_be_bytes([arr[4], arr[5]]),
+            u16::from_be_bytes([arr[6], arr[7]]),
+            u16::from_be_bytes([arr[8], arr[9]]),
+            u16::from_be_bytes([arr[10], arr[11]]),
+            u16::from_be_bytes([arr[12], arr[13]]),
+            u16::from_be_bytes([arr[14], arr[15]]),
         ]
     }
 
@@ -1384,21 +1393,43 @@ impl FromInner<c::in6_addr> for Ipv6Addr {
 
 #[stable(feature = "i128", since = "1.26.0")]
 impl From<Ipv6Addr> for u128 {
+    /// Convert an `Ipv6Addr` into a host byte order `u128`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::Ipv6Addr;
+    ///
+    /// let addr = Ipv6Addr::new(
+    ///     0x1020, 0x3040, 0x5060, 0x7080,
+    ///     0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
+    /// );
+    /// assert_eq!(0x102030405060708090A0B0C0D0E0F00D_u128, u128::from(addr));
+    /// ```
     fn from(ip: Ipv6Addr) -> u128 {
-        let ip = ip.segments();
-        ((ip[0] as u128) << 112) + ((ip[1] as u128) << 96) + ((ip[2] as u128) << 80) +
-            ((ip[3] as u128) << 64) + ((ip[4] as u128) << 48) + ((ip[5] as u128) << 32) +
-            ((ip[6] as u128) << 16) + (ip[7] as u128)
+        let ip = ip.octets();
+        u128::from_be_bytes(ip)
     }
 }
 #[stable(feature = "i128", since = "1.26.0")]
 impl From<u128> for Ipv6Addr {
+    /// Convert a host byte order `u128` into an `Ipv6Addr`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::net::Ipv6Addr;
+    ///
+    /// let addr = Ipv6Addr::from(0x102030405060708090A0B0C0D0E0F00D_u128);
+    /// assert_eq!(
+    ///     Ipv6Addr::new(
+    ///         0x1020, 0x3040, 0x5060, 0x7080,
+    ///         0x90A0, 0xB0C0, 0xD0E0, 0xF00D,
+    ///     ),
+    ///     addr);
+    /// ```
     fn from(ip: u128) -> Ipv6Addr {
-        Ipv6Addr::new(
-            (ip >> 112) as u16, (ip >> 96) as u16, (ip >> 80) as u16,
-            (ip >> 64) as u16, (ip >> 48) as u16, (ip >> 32) as u16,
-            (ip >> 16) as u16, ip as u16,
-        )
+        Ipv6Addr::from(ip.to_be_bytes())
     }
 }
 
@@ -1421,7 +1452,7 @@ impl From<[u16; 8]> for Ipv6Addr {
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
 impl From<[u8; 16]> for IpAddr {
-    /// Create an `IpAddr::V6` from a sixteen element byte array.
+    /// Creates an `IpAddr::V6` from a sixteen element byte array.
     ///
     /// # Examples
     ///
@@ -1449,7 +1480,7 @@ impl From<[u8; 16]> for IpAddr {
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
 impl From<[u16; 8]> for IpAddr {
-    /// Create an `IpAddr::V6` from an eight element 16-bit array.
+    /// Creates an `IpAddr::V6` from an eight element 16-bit array.
     ///
     /// # Examples
     ///
diff --git a/src/libstd/net/tcp.rs b/src/libstd/net/tcp.rs
index 86ecb10edf2f9..51bd76ae4363e 100644
--- a/src/libstd/net/tcp.rs
+++ b/src/libstd/net/tcp.rs
@@ -497,7 +497,7 @@ impl TcpStream {
         self.0.ttl()
     }
 
-    /// Get the value of the `SO_ERROR` option on this socket.
+    /// Gets the value of the `SO_ERROR` option on this socket.
     ///
     /// This will retrieve the stored error in the underlying socket, clearing
     /// the field in the process. This can be useful for checking errors between
@@ -580,7 +580,7 @@ impl Write for TcpStream {
     fn flush(&mut self) -> io::Result<()> { Ok(()) }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Read for &'a TcpStream {
+impl Read for &TcpStream {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { self.0.read(buf) }
 
     #[inline]
@@ -589,7 +589,7 @@ impl<'a> Read for &'a TcpStream {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Write for &'a TcpStream {
+impl Write for &TcpStream {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.write(buf) }
     fn flush(&mut self) -> io::Result<()> { Ok(()) }
 }
@@ -636,7 +636,7 @@ impl TcpListener {
     ///
     /// # Examples
     ///
-    /// Create a TCP listener bound to `127.0.0.1:80`:
+    /// Creates a TCP listener bound to `127.0.0.1:80`:
     ///
     /// ```no_run
     /// use std::net::TcpListener;
@@ -644,7 +644,7 @@ impl TcpListener {
     /// let listener = TcpListener::bind("127.0.0.1:80").unwrap();
     /// ```
     ///
-    /// Create a TCP listener bound to `127.0.0.1:80`. If that fails, create a
+    /// Creates a TCP listener bound to `127.0.0.1:80`. If that fails, create a
     /// TCP listener bound to `127.0.0.1:443`:
     ///
     /// ```no_run
@@ -811,7 +811,7 @@ impl TcpListener {
         self.0.only_v6()
     }
 
-    /// Get the value of the `SO_ERROR` option on this socket.
+    /// Gets the value of the `SO_ERROR` option on this socket.
     ///
     /// This will retrieve the stored error in the underlying socket, clearing
     /// the field in the process. This can be useful for checking errors between
@@ -1187,9 +1187,13 @@ mod tests {
     #[test]
     fn double_bind() {
         each_ip(&mut |addr| {
-            let _listener = t!(TcpListener::bind(&addr));
+            let listener1 = t!(TcpListener::bind(&addr));
             match TcpListener::bind(&addr) {
-                Ok(..) => panic!(),
+                Ok(listener2) => panic!(
+                    "This system (perhaps due to options set by TcpListener::bind) \
+                     permits double binding: {:?} and {:?}",
+                    listener1, listener2
+                ),
                 Err(e) => {
                     assert!(e.kind() == ErrorKind::ConnectionRefused ||
                             e.kind() == ErrorKind::Other ||
diff --git a/src/libstd/net/udp.rs b/src/libstd/net/udp.rs
index 83459946ba6de..d49871ce7bd86 100644
--- a/src/libstd/net/udp.rs
+++ b/src/libstd/net/udp.rs
@@ -69,7 +69,7 @@ impl UdpSocket {
     ///
     /// # Examples
     ///
-    /// Create a UDP socket bound to `127.0.0.1:3400`:
+    /// Creates a UDP socket bound to `127.0.0.1:3400`:
     ///
     /// ```no_run
     /// use std::net::UdpSocket;
@@ -77,7 +77,7 @@ impl UdpSocket {
     /// let socket = UdpSocket::bind("127.0.0.1:3400").expect("couldn't bind to address");
     /// ```
     ///
-    /// Create a UDP socket bound to `127.0.0.1:3400`. If the socket cannot be
+    /// Creates a UDP socket bound to `127.0.0.1:3400`. If the socket cannot be
     /// bound to that address, create a UDP socket bound to `127.0.0.1:3401`:
     ///
     /// ```no_run
@@ -158,7 +158,7 @@ impl UdpSocket {
     /// This will return an error when the IP version of the local socket
     /// does not match that returned from [`ToSocketAddrs`].
     ///
-    /// See <https://github.com/rust-lang/rust/issues/34202> for more details.
+    /// See issue #34202 for more details.
     ///
     /// [`ToSocketAddrs`]: ../../std/net/trait.ToSocketAddrs.html
     ///
@@ -590,7 +590,7 @@ impl UdpSocket {
         self.0.leave_multicast_v6(multiaddr, interface)
     }
 
-    /// Get the value of the `SO_ERROR` option on this socket.
+    /// Gets the value of the `SO_ERROR` option on this socket.
     ///
     /// This will retrieve the stored error in the underlying socket, clearing
     /// the field in the process. This can be useful for checking errors between
@@ -627,7 +627,7 @@ impl UdpSocket {
     ///
     /// # Examples
     ///
-    /// Create a UDP socket bound to `127.0.0.1:3400` and connect the socket to
+    /// Creates a UDP socket bound to `127.0.0.1:3400` and connect the socket to
     /// `127.0.0.1:8080`:
     ///
     /// ```no_run
@@ -756,7 +756,7 @@ impl UdpSocket {
     ///
     /// # Examples
     ///
-    /// Create a UDP socket bound to `127.0.0.1:7878` and read bytes in
+    /// Creates a UDP socket bound to `127.0.0.1:7878` and read bytes in
     /// nonblocking mode:
     ///
     /// ```no_run
diff --git a/src/libstd/os/fortanix_sgx/mod.rs b/src/libstd/os/fortanix_sgx/mod.rs
index 47c7b5dcbe64a..bd6f4b4465b24 100644
--- a/src/libstd/os/fortanix_sgx/mod.rs
+++ b/src/libstd/os/fortanix_sgx/mod.rs
@@ -16,31 +16,16 @@ pub mod usercalls {
     /// Primitives for allocating memory in userspace as well as copying data
     /// to and from user memory.
     pub mod alloc {
-        pub use sys::abi::usercalls::alloc;
+        pub use sys::abi::usercalls::alloc::*;
     }
 
     /// Lowest-level interfaces to usercalls and usercall ABI type definitions.
     pub mod raw {
-        use sys::abi::usercalls::raw::invoke_with_usercalls;
-        pub use sys::abi::usercalls::raw::do_usercall;
+        pub use sys::abi::usercalls::raw::{do_usercall, Usercalls as UsercallNrs};
         pub use sys::abi::usercalls::raw::{accept_stream, alloc, async_queues, bind_stream, close,
                                            connect_stream, exit, flush, free, insecure_time,
                                            launch_thread, read, read_alloc, send, wait, write};
 
-        macro_rules! define_usercallnrs {
-            ($(fn $f:ident($($n:ident: $t:ty),*) $(-> $r:ty)*; )*) => {
-                /// Usercall numbers as per the ABI.
-                #[repr(C)]
-                #[unstable(feature = "sgx_platform", issue = "56975")]
-                #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
-                #[allow(missing_docs)]
-                pub enum UsercallNrs {
-                    $($f,)*
-                }
-            };
-        }
-        invoke_with_usercalls!(define_usercallnrs);
-
         // fortanix-sgx-abi re-exports
         pub use sys::abi::usercalls::raw::{ByteBuffer, FifoDescriptor, Return, Usercall};
         pub use sys::abi::usercalls::raw::Error;
@@ -56,4 +41,4 @@ pub mod mem {
     pub use sys::abi::mem::*;
 }
 
-pub use sys::ext::{io, arch};
+pub use sys::ext::{io, arch, ffi};
diff --git a/src/libstd/panic.rs b/src/libstd/panic.rs
index d27f6ca88c2e9..daeac7107a56c 100644
--- a/src/libstd/panic.rs
+++ b/src/libstd/panic.rs
@@ -12,7 +12,7 @@ use panicking;
 use ptr::{Unique, NonNull};
 use rc::Rc;
 use sync::{Arc, Mutex, RwLock, atomic};
-use task::{LocalWaker, Poll};
+use task::{Waker, Poll};
 use thread::Result;
 
 #[stable(feature = "panic_hooks", since = "1.10.0")]
@@ -199,9 +199,9 @@ pub struct AssertUnwindSafe<T>(
 // * Our custom AssertUnwindSafe wrapper is indeed unwind safe
 
 #[stable(feature = "catch_unwind", since = "1.9.0")]
-impl<'a, T: ?Sized> !UnwindSafe for &'a mut T {}
+impl<T: ?Sized> !UnwindSafe for &mut T {}
 #[stable(feature = "catch_unwind", since = "1.9.0")]
-impl<'a, T: RefUnwindSafe + ?Sized> UnwindSafe for &'a T {}
+impl<T: RefUnwindSafe + ?Sized> UnwindSafe for &T {}
 #[stable(feature = "catch_unwind", since = "1.9.0")]
 impl<T: RefUnwindSafe + ?Sized> UnwindSafe for *const T {}
 #[stable(feature = "catch_unwind", since = "1.9.0")]
@@ -320,12 +320,12 @@ impl<T: fmt::Debug> fmt::Debug for AssertUnwindSafe<T> {
 }
 
 #[unstable(feature = "futures_api", issue = "50547")]
-impl<'a, F: Future> Future for AssertUnwindSafe<F> {
+impl<F: Future> Future for AssertUnwindSafe<F> {
     type Output = F::Output;
 
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
         let pinned_field = unsafe { Pin::map_unchecked_mut(self, |x| &mut x.0) };
-        F::poll(pinned_field, lw)
+        F::poll(pinned_field, waker)
     }
 }
 
diff --git a/src/libstd/path.rs b/src/libstd/path.rs
index 5c7bff70a0dcd..240b92a17db4c 100644
--- a/src/libstd/path.rs
+++ b/src/libstd/path.rs
@@ -457,14 +457,14 @@ impl<'a> cmp::PartialOrd for PrefixComponent<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> cmp::Ord for PrefixComponent<'a> {
-    fn cmp(&self, other: &PrefixComponent<'a>) -> cmp::Ordering {
+impl cmp::Ord for PrefixComponent<'_> {
+    fn cmp(&self, other: &Self) -> cmp::Ordering {
         cmp::Ord::cmp(&self.parsed, &other.parsed)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> Hash for PrefixComponent<'a> {
+impl Hash for PrefixComponent<'_> {
     fn hash<H: Hasher>(&self, h: &mut H) {
         self.parsed.hash(h);
     }
@@ -561,14 +561,14 @@ impl<'a> Component<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> AsRef<OsStr> for Component<'a> {
+impl AsRef<OsStr> for Component<'_> {
     fn as_ref(&self) -> &OsStr {
         self.as_os_str()
     }
 }
 
 #[stable(feature = "path_component_asref", since = "1.25.0")]
-impl<'a> AsRef<Path> for Component<'a> {
+impl AsRef<Path> for Component<'_> {
     fn as_ref(&self) -> &Path {
         self.as_os_str().as_ref()
     }
@@ -630,11 +630,11 @@ pub struct Iter<'a> {
 }
 
 #[stable(feature = "path_components_debug", since = "1.13.0")]
-impl<'a> fmt::Debug for Components<'a> {
+impl fmt::Debug for Components<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         struct DebugHelper<'a>(&'a Path);
 
-        impl<'a> fmt::Debug for DebugHelper<'a> {
+        impl fmt::Debug for DebugHelper<'_> {
             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 f.debug_list()
                     .entries(self.0.components())
@@ -814,25 +814,25 @@ impl<'a> Components<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> AsRef<Path> for Components<'a> {
+impl AsRef<Path> for Components<'_> {
     fn as_ref(&self) -> &Path {
         self.as_path()
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> AsRef<OsStr> for Components<'a> {
+impl AsRef<OsStr> for Components<'_> {
     fn as_ref(&self) -> &OsStr {
         self.as_path().as_os_str()
     }
 }
 
 #[stable(feature = "path_iter_debug", since = "1.13.0")]
-impl<'a> fmt::Debug for Iter<'a> {
+impl fmt::Debug for Iter<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         struct DebugHelper<'a>(&'a Path);
 
-        impl<'a> fmt::Debug for DebugHelper<'a> {
+        impl fmt::Debug for DebugHelper<'_> {
             fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                 f.debug_list()
                     .entries(self.0.iter())
@@ -867,14 +867,14 @@ impl<'a> Iter<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> AsRef<Path> for Iter<'a> {
+impl AsRef<Path> for Iter<'_> {
     fn as_ref(&self) -> &Path {
         self.as_path()
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> AsRef<OsStr> for Iter<'a> {
+impl AsRef<OsStr> for Iter<'_> {
     fn as_ref(&self) -> &OsStr {
         self.as_path().as_os_str()
     }
@@ -897,7 +897,7 @@ impl<'a> DoubleEndedIterator for Iter<'a> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a> FusedIterator for Iter<'a> {}
+impl FusedIterator for Iter<'_> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> Iterator for Components<'a> {
@@ -1000,7 +1000,7 @@ impl<'a> DoubleEndedIterator for Components<'a> {
 }
 
 #[stable(feature = "fused", since = "1.26.0")]
-impl<'a> FusedIterator for Components<'a> {}
+impl FusedIterator for Components<'_> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> cmp::PartialEq for Components<'a> {
@@ -1010,7 +1010,7 @@ impl<'a> cmp::PartialEq for Components<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> cmp::Eq for Components<'a> {}
+impl cmp::Eq for Components<'_> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<'a> cmp::PartialOrd for Components<'a> {
@@ -1020,8 +1020,8 @@ impl<'a> cmp::PartialOrd for Components<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> cmp::Ord for Components<'a> {
-    fn cmp(&self, other: &Components<'a>) -> cmp::Ordering {
+impl cmp::Ord for Components<'_> {
+    fn cmp(&self, other: &Self) -> cmp::Ordering {
         Iterator::cmp(self.clone(), other.clone())
     }
 }
@@ -1063,7 +1063,7 @@ impl<'a> Iterator for Ancestors<'a> {
 }
 
 #[stable(feature = "path_ancestors", since = "1.28.0")]
-impl<'a> FusedIterator for Ancestors<'a> {}
+impl FusedIterator for Ancestors<'_> {}
 
 ////////////////////////////////////////////////////////////////////////////////
 // Basic types and traits
@@ -1145,6 +1145,33 @@ impl PathBuf {
         PathBuf { inner: OsString::new() }
     }
 
+    /// Creates a new `PathBuf` with a given capacity used to create the
+    /// internal [`OsString`]. See [`with_capacity`] defined on [`OsString`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(path_buf_capacity)]
+    /// use std::path::PathBuf;
+    ///
+    /// let mut path = PathBuf::with_capacity(10);
+    /// let capacity = path.capacity();
+    ///
+    /// // This push is done without reallocating
+    /// path.push(r"C:\");
+    ///
+    /// assert_eq!(capacity, path.capacity());
+    /// ```
+    ///
+    /// [`with_capacity`]: ../ffi/struct.OsString.html#method.with_capacity
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn with_capacity(capacity: usize) -> PathBuf {
+        PathBuf {
+            inner: OsString::with_capacity(capacity)
+        }
+    }
+
     /// Coerces to a [`Path`] slice.
     ///
     /// [`Path`]: struct.Path.html
@@ -1230,12 +1257,11 @@ impl PathBuf {
 
     /// Truncates `self` to [`self.parent`].
     ///
-    /// Returns `false` and does nothing if [`self.file_name`] is [`None`].
+    /// Returns `false` and does nothing if [`self.parent`] is [`None`].
     /// Otherwise, returns `true`.
     ///
     /// [`None`]: ../../std/option/enum.Option.html#variant.None
     /// [`self.parent`]: struct.PathBuf.html#method.parent
-    /// [`self.file_name`]: struct.PathBuf.html#method.file_name
     ///
     /// # Examples
     ///
@@ -1374,6 +1400,60 @@ impl PathBuf {
         let rw = Box::into_raw(self.inner.into_boxed_os_str()) as *mut Path;
         unsafe { Box::from_raw(rw) }
     }
+
+    /// Invokes [`capacity`] on the underlying instance of [`OsString`].
+    ///
+    /// [`capacity`]: ../ffi/struct.OsString.html#method.capacity
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn capacity(&self) -> usize {
+        self.inner.capacity()
+    }
+
+    /// Invokes [`clear`] on the underlying instance of [`OsString`].
+    ///
+    /// [`clear`]: ../ffi/struct.OsString.html#method.clear
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn clear(&mut self) {
+        self.inner.clear()
+    }
+
+    /// Invokes [`reserve`] on the underlying instance of [`OsString`].
+    ///
+    /// [`reserve`]: ../ffi/struct.OsString.html#method.reserve
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn reserve(&mut self, additional: usize) {
+        self.inner.reserve(additional)
+    }
+
+    /// Invokes [`reserve_exact`] on the underlying instance of [`OsString`].
+    ///
+    /// [`reserve_exact`]: ../ffi/struct.OsString.html#method.reserve_exact
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn reserve_exact(&mut self, additional: usize) {
+        self.inner.reserve_exact(additional)
+    }
+
+    /// Invokes [`shrink_to_fit`] on the underlying instance of [`OsString`].
+    ///
+    /// [`shrink_to_fit`]: ../ffi/struct.OsString.html#method.shrink_to_fit
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn shrink_to_fit(&mut self) {
+        self.inner.shrink_to_fit()
+    }
+
+    /// Invokes [`shrink_to`] on the underlying instance of [`OsString`].
+    ///
+    /// [`shrink_to`]: ../ffi/struct.OsString.html#method.shrink_to
+    /// [`OsString`]: ../ffi/struct.OsString.html
+    #[unstable(feature = "path_buf_capacity", issue = "58234")]
+    pub fn shrink_to(&mut self, min_capacity: usize) {
+        self.inner.shrink_to(min_capacity)
+    }
 }
 
 #[stable(feature = "box_from_path", since = "1.17.0")]
@@ -2393,7 +2473,7 @@ impl Path {
         fs::read_dir(self)
     }
 
-    /// Returns whether the path points at an existing entity.
+    /// Returns `true` if the path points at an existing entity.
     ///
     /// This function will traverse symbolic links to query information about the
     /// destination file. In case of broken symbolic links this will return `false`.
@@ -2419,7 +2499,7 @@ impl Path {
         fs::metadata(self).is_ok()
     }
 
-    /// Returns whether the path exists on disk and is pointing at a regular file.
+    /// Returns `true` if the path exists on disk and is pointing at a regular file.
     ///
     /// This function will traverse symbolic links to query information about the
     /// destination file. In case of broken symbolic links this will return `false`.
@@ -2448,7 +2528,7 @@ impl Path {
         fs::metadata(self).map(|m| m.is_file()).unwrap_or(false)
     }
 
-    /// Returns whether the path exists on disk and is pointing at a directory.
+    /// Returns `true` if the path exists on disk and is pointing at a directory.
     ///
     /// This function will traverse symbolic links to query information about the
     /// destination file. In case of broken symbolic links this will return `false`.
@@ -2530,14 +2610,14 @@ pub struct Display<'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> fmt::Debug for Display<'a> {
+impl fmt::Debug for Display<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         fmt::Debug::fmt(&self.path, f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a> fmt::Display for Display<'a> {
+impl fmt::Display for Display<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.path.inner.display(f)
     }
@@ -2591,7 +2671,7 @@ impl AsRef<Path> for OsStr {
 }
 
 #[stable(feature = "cow_os_str_as_ref_path", since = "1.8.0")]
-impl<'a> AsRef<Path> for Cow<'a, OsStr> {
+impl AsRef<Path> for Cow<'_, OsStr> {
     fn as_ref(&self) -> &Path {
         Path::new(self)
     }
diff --git a/src/libstd/prelude/mod.rs b/src/libstd/prelude/mod.rs
index ec8318f3728eb..551e982a3c685 100644
--- a/src/libstd/prelude/mod.rs
+++ b/src/libstd/prelude/mod.rs
@@ -44,8 +44,8 @@
 //! The current version of the prelude (version 1) lives in
 //! [`std::prelude::v1`], and re-exports the following.
 //!
-//! * [`std::marker`]::{[`Copy`], [`Send`], [`Sized`], [`Sync`]}. The marker
-//!   traits indicate fundamental properties of types.
+//! * [`std::marker`]::{[`Copy`], [`Send`], [`Sized`], [`Sync`], [`Unpin`]}. The
+//!   marker traits indicate fundamental properties of types.
 //! * [`std::ops`]::{[`Drop`], [`Fn`], [`FnMut`], [`FnOnce`]}. Various
 //!   operations for both destructors and overloading `()`.
 //! * [`std::mem`]::[`drop`][`mem::drop`], a convenience function for explicitly
@@ -108,6 +108,7 @@
 //! [`Sync`]: ../marker/trait.Sync.html
 //! [`ToOwned`]: ../borrow/trait.ToOwned.html
 //! [`ToString`]: ../string/trait.ToString.html
+//! [`Unpin`]: ../marker/trait.Unpin.html
 //! [`Vec`]: ../vec/struct.Vec.html
 //! [`Clone::clone`]: ../clone/trait.Clone.html#tymethod.clone
 //! [`mem::drop`]: ../mem/fn.drop.html
@@ -128,10 +129,10 @@
 //! [`std::string`]: ../string/index.html
 //! [`std::vec`]: ../vec/index.html
 //! [`to_owned`]: ../borrow/trait.ToOwned.html#tymethod.to_owned
-//! [book-closures]: ../../book/first-edition/closures.html
-//! [book-dtor]: ../../book/first-edition/drop.html
-//! [book-enums]: ../../book/first-edition/enums.html
-//! [book-iter]: ../../book/first-edition/iterators.html
+//! [book-closures]: ../../book/ch13-01-closures.html
+//! [book-dtor]: ../../book/ch15-03-drop.html
+//! [book-enums]: ../../book/ch06-01-defining-an-enum.html
+//! [book-iter]: ../../book/ch13-02-iterators.html
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
diff --git a/src/libstd/primitive_docs.rs b/src/libstd/primitive_docs.rs
index c2751508ce094..6bb7f28efebcf 100644
--- a/src/libstd/primitive_docs.rs
+++ b/src/libstd/primitive_docs.rs
@@ -126,7 +126,7 @@ mod prim_bool { }
 ///
 /// ```ignore (string-from-str-error-type-is-not-never-yet)
 /// #[feature(exhaustive_patterns)]
-/// // NOTE: This does not work today!
+/// // NOTE: this does not work today!
 /// let Ok(s) = String::from_str("hello");
 /// ```
 ///
@@ -1062,7 +1062,7 @@ mod prim_ref { }
 /// On top of that, function pointers can vary based on what ABI they use. This is achieved by
 /// adding the `extern` keyword to the type name, followed by the ABI in question. For example,
 /// `fn()` is different from `extern "C" fn()`, which itself is different from `extern "stdcall"
-/// fn()`, and so on for the various ABIs that Rust supports.  Non-`extern` functions have an ABI
+/// fn()`, and so on for the various ABIs that Rust supports. Non-`extern` functions have an ABI
 /// of `"Rust"`, and `extern` functions without an explicit ABI have an ABI of `"C"`. For more
 /// information, see [the nomicon's section on foreign calling conventions][nomicon-abi].
 ///
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index 1263ef82e4872..a2ef85016d8a2 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -427,7 +427,7 @@ impl Command {
     /// The search path to be used may be controlled by setting the
     /// `PATH` environment variable on the Command,
     /// but this has some implementation limitations on Windows
-    /// (see <https://github.com/rust-lang/rust/issues/37519>).
+    /// (see issue #37519).
     ///
     /// # Examples
     ///
@@ -445,7 +445,7 @@ impl Command {
         Command { inner: imp::Command::new(program.as_ref()) }
     }
 
-    /// Add an argument to pass to the program.
+    /// Adds an argument to pass to the program.
     ///
     /// Only one argument can be passed per use. So instead of:
     ///
@@ -487,7 +487,7 @@ impl Command {
         self
     }
 
-    /// Add multiple arguments to pass to the program.
+    /// Adds multiple arguments to pass to the program.
     ///
     /// To pass a single argument see [`arg`].
     ///
@@ -540,7 +540,7 @@ impl Command {
         self
     }
 
-    /// Add or update multiple environment variable mappings.
+    /// Adds or updates multiple environment variable mappings.
     ///
     /// # Examples
     ///
@@ -1287,7 +1287,7 @@ impl Child {
     ///
     /// let mut command = Command::new("ls");
     /// if let Ok(child) = command.spawn() {
-    ///     println!("Child's id is {}", child.id());
+    ///     println!("Child's ID is {}", child.id());
     /// } else {
     ///     println!("ls command didn't start");
     /// }
@@ -1332,7 +1332,7 @@ impl Child {
     ///
     /// This function will not block the calling thread and will only
     /// check to see if the child process has exited or not. If the child has
-    /// exited then on Unix the process id is reaped. This function is
+    /// exited then on Unix the process ID is reaped. This function is
     /// guaranteed to repeatedly return a successful exit status so long as the
     /// child has already exited.
     ///
@@ -1979,7 +1979,7 @@ mod tests {
         }
     }
 
-    /// Test that process creation flags work by debugging a process.
+    /// Tests that process creation flags work by debugging a process.
     /// Other creation flags make it hard or impossible to detect
     /// behavioral changes in the process.
     #[test]
diff --git a/src/libstd/sync/barrier.rs b/src/libstd/sync/barrier.rs
index f248c721e9ad2..bc2e14d436a99 100644
--- a/src/libstd/sync/barrier.rs
+++ b/src/libstd/sync/barrier.rs
@@ -159,7 +159,7 @@ impl fmt::Debug for BarrierWaitResult {
 }
 
 impl BarrierWaitResult {
-    /// Returns whether this thread from [`wait`] is the "leader thread".
+    /// Returns `true` if this thread from [`wait`] is the "leader thread".
     ///
     /// Only one thread will have `true` returned from their result, all other
     /// threads will have `false` returned.
diff --git a/src/libstd/sync/condvar.rs b/src/libstd/sync/condvar.rs
index 7688737910676..036aff090ead9 100644
--- a/src/libstd/sync/condvar.rs
+++ b/src/libstd/sync/condvar.rs
@@ -17,7 +17,7 @@ use time::{Duration, Instant};
 pub struct WaitTimeoutResult(bool);
 
 impl WaitTimeoutResult {
-    /// Returns whether the wait was known to have timed out.
+    /// Returns `true` if the wait was known to have timed out.
     ///
     /// # Examples
     ///
@@ -343,13 +343,13 @@ impl Condvar {
     ///
     /// Note that the best effort is made to ensure that the time waited is
     /// measured with a monotonic clock, and not affected by the changes made to
-    /// the system time.  This function is susceptible to spurious wakeups.
+    /// the system time. This function is susceptible to spurious wakeups.
     /// Condition variables normally have a boolean predicate associated with
     /// them, and the predicate must always be checked each time this function
-    /// returns to protect against spurious wakeups.  Additionally, it is
+    /// returns to protect against spurious wakeups. Additionally, it is
     /// typically desirable for the time-out to not exceed some duration in
     /// spite of spurious wakes, thus the sleep-duration is decremented by the
-    /// amount slept.  Alternatively, use the `wait_timeout_until` method
+    /// amount slept. Alternatively, use the `wait_timeout_until` method
     /// to wait until a condition is met with a total time-out regardless
     /// of spurious wakes.
     ///
@@ -413,7 +413,7 @@ impl Condvar {
     }
 
     /// Waits on this condition variable for a notification, timing out after a
-    /// specified duration.  Spurious wakes will not cause this function to
+    /// specified duration. Spurious wakes will not cause this function to
     /// return.
     ///
     /// The semantics of this function are equivalent to [`wait_until`] except
diff --git a/src/libstd/sync/mpsc/blocking.rs b/src/libstd/sync/mpsc/blocking.rs
index ae5a18adbb3c0..eaf09a16756b2 100644
--- a/src/libstd/sync/mpsc/blocking.rs
+++ b/src/libstd/sync/mpsc/blocking.rs
@@ -50,14 +50,14 @@ impl SignalToken {
         wake
     }
 
-    /// Convert to an unsafe usize value. Useful for storing in a pipe's state
+    /// Converts to an unsafe usize value. Useful for storing in a pipe's state
     /// flag.
     #[inline]
     pub unsafe fn cast_to_usize(self) -> usize {
         mem::transmute(self.inner)
     }
 
-    /// Convert from an unsafe usize value. Useful for retrieving a pipe's state
+    /// Converts from an unsafe usize value. Useful for retrieving a pipe's state
     /// flag.
     #[inline]
     pub unsafe fn cast_from_usize(signal_ptr: usize) -> SignalToken {
@@ -72,7 +72,7 @@ impl WaitToken {
         }
     }
 
-    /// Returns true if we wake up normally, false otherwise.
+    /// Returns `true` if we wake up normally.
     pub fn wait_max_until(self, end: Instant) -> bool {
         while !self.inner.woken.load(Ordering::SeqCst) {
             let now = Instant::now();
diff --git a/src/libstd/sync/mpsc/mod.rs b/src/libstd/sync/mpsc/mod.rs
index 446c164965d6f..5273345c6b4fd 100644
--- a/src/libstd/sync/mpsc/mod.rs
+++ b/src/libstd/sync/mpsc/mod.rs
@@ -279,6 +279,9 @@ use self::select::StartResult;
 use self::select::StartResult::*;
 use self::blocking::SignalToken;
 
+#[cfg(all(test, not(target_os = "emscripten")))]
+mod select_tests;
+
 mod blocking;
 mod oneshot;
 mod select;
@@ -789,7 +792,7 @@ impl<T> Sender<T> {
     /// where the corresponding receiver has already been deallocated. Note
     /// that a return value of [`Err`] means that the data will never be
     /// received, but a return value of [`Ok`] does *not* mean that the data
-    /// will be received.  It is possible for the corresponding receiver to
+    /// will be received. It is possible for the corresponding receiver to
     /// hang up immediately after this function returns [`Ok`].
     ///
     /// [`Err`]: ../../../std/result/enum.Result.html#variant.Err
diff --git a/src/libstd/sync/mpsc/select.rs b/src/libstd/sync/mpsc/select.rs
index 8f41680a818b9..8591b55dc58ee 100644
--- a/src/libstd/sync/mpsc/select.rs
+++ b/src/libstd/sync/mpsc/select.rs
@@ -72,11 +72,11 @@ struct SelectInner {
 impl !marker::Send for Select {}
 
 /// A handle to a receiver which is currently a member of a `Select` set of
-/// receivers.  This handle is used to keep the receiver in the set as well as
+/// receivers. This handle is used to keep the receiver in the set as well as
 /// interact with the underlying receiver.
 pub struct Handle<'rx, T:Send+'rx> {
     /// The ID of this handle, used to compare against the return value of
-    /// `Select::wait()`
+    /// `Select::wait()`.
     id: usize,
     selector: *mut SelectInner,
     next: *mut Handle<'static, ()>,
@@ -148,7 +148,7 @@ impl Select {
     }
 
     /// Waits for an event on this receiver set. The returned value is *not* an
-    /// index, but rather an id. This id can be queried against any active
+    /// index, but rather an ID. This ID can be queried against any active
     /// `Handle` structures (each one has an `id` method). The handle with
     /// the matching `id` will have some sort of event available on it. The
     /// event could either be that data is available or the corresponding
@@ -158,7 +158,7 @@ impl Select {
     }
 
     /// Helper method for skipping the preflight checks during testing
-    fn wait2(&self, do_preflight_checks: bool) -> usize {
+    pub(super) fn wait2(&self, do_preflight_checks: bool) -> usize {
         // Note that this is currently an inefficient implementation. We in
         // theory have knowledge about all receivers in the set ahead of time,
         // so this method shouldn't really have to iterate over all of them yet
@@ -251,7 +251,7 @@ impl Select {
 }
 
 impl<'rx, T: Send> Handle<'rx, T> {
-    /// Retrieves the id of this handle.
+    /// Retrieves the ID of this handle.
     #[inline]
     pub fn id(&self) -> usize { self.id }
 
@@ -321,7 +321,7 @@ impl Drop for Select {
     }
 }
 
-impl<'rx, T: Send> Drop for Handle<'rx, T> {
+impl<T: Send> Drop for Handle<'_, T> {
     fn drop(&mut self) {
         unsafe { self.remove() }
     }
@@ -347,422 +347,8 @@ impl fmt::Debug for Select {
     }
 }
 
-impl<'rx, T:Send+'rx> fmt::Debug for Handle<'rx, T> {
+impl<T: Send> fmt::Debug for Handle<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("Handle").finish()
     }
 }
-
-#[allow(unused_imports)]
-#[cfg(all(test, not(target_os = "emscripten")))]
-mod tests {
-    use thread;
-    use sync::mpsc::*;
-
-    // Don't use the libstd version so we can pull in the right Select structure
-    // (std::comm points at the wrong one)
-    macro_rules! select {
-        (
-            $($name:pat = $rx:ident.$meth:ident() => $code:expr),+
-        ) => ({
-            let sel = Select::new();
-            $( let mut $rx = sel.handle(&$rx); )+
-            unsafe {
-                $( $rx.add(); )+
-            }
-            let ret = sel.wait();
-            $( if ret == $rx.id() { let $name = $rx.$meth(); $code } else )+
-            { unreachable!() }
-        })
-    }
-
-    #[test]
-    fn smoke() {
-        let (tx1, rx1) = channel::<i32>();
-        let (tx2, rx2) = channel::<i32>();
-        tx1.send(1).unwrap();
-        select! {
-            foo = rx1.recv() => { assert_eq!(foo.unwrap(), 1); },
-            _bar = rx2.recv() => { panic!() }
-        }
-        tx2.send(2).unwrap();
-        select! {
-            _foo = rx1.recv() => { panic!() },
-            bar = rx2.recv() => { assert_eq!(bar.unwrap(), 2) }
-        }
-        drop(tx1);
-        select! {
-            foo = rx1.recv() => { assert!(foo.is_err()); },
-            _bar = rx2.recv() => { panic!() }
-        }
-        drop(tx2);
-        select! {
-            bar = rx2.recv() => { assert!(bar.is_err()); }
-        }
-    }
-
-    #[test]
-    fn smoke2() {
-        let (_tx1, rx1) = channel::<i32>();
-        let (_tx2, rx2) = channel::<i32>();
-        let (_tx3, rx3) = channel::<i32>();
-        let (_tx4, rx4) = channel::<i32>();
-        let (tx5, rx5) = channel::<i32>();
-        tx5.send(4).unwrap();
-        select! {
-            _foo = rx1.recv() => { panic!("1") },
-            _foo = rx2.recv() => { panic!("2") },
-            _foo = rx3.recv() => { panic!("3") },
-            _foo = rx4.recv() => { panic!("4") },
-            foo = rx5.recv() => { assert_eq!(foo.unwrap(), 4); }
-        }
-    }
-
-    #[test]
-    fn closed() {
-        let (_tx1, rx1) = channel::<i32>();
-        let (tx2, rx2) = channel::<i32>();
-        drop(tx2);
-
-        select! {
-            _a1 = rx1.recv() => { panic!() },
-            a2 = rx2.recv() => { assert!(a2.is_err()); }
-        }
-    }
-
-    #[test]
-    fn unblocks() {
-        let (tx1, rx1) = channel::<i32>();
-        let (_tx2, rx2) = channel::<i32>();
-        let (tx3, rx3) = channel::<i32>();
-
-        let _t = thread::spawn(move|| {
-            for _ in 0..20 { thread::yield_now(); }
-            tx1.send(1).unwrap();
-            rx3.recv().unwrap();
-            for _ in 0..20 { thread::yield_now(); }
-        });
-
-        select! {
-            a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
-            _b = rx2.recv() => { panic!() }
-        }
-        tx3.send(1).unwrap();
-        select! {
-            a = rx1.recv() => { assert!(a.is_err()) },
-            _b = rx2.recv() => { panic!() }
-        }
-    }
-
-    #[test]
-    fn both_ready() {
-        let (tx1, rx1) = channel::<i32>();
-        let (tx2, rx2) = channel::<i32>();
-        let (tx3, rx3) = channel::<()>();
-
-        let _t = thread::spawn(move|| {
-            for _ in 0..20 { thread::yield_now(); }
-            tx1.send(1).unwrap();
-            tx2.send(2).unwrap();
-            rx3.recv().unwrap();
-        });
-
-        select! {
-            a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
-            a = rx2.recv() => { assert_eq!(a.unwrap(), 2); }
-        }
-        select! {
-            a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
-            a = rx2.recv() => { assert_eq!(a.unwrap(), 2); }
-        }
-        assert_eq!(rx1.try_recv(), Err(TryRecvError::Empty));
-        assert_eq!(rx2.try_recv(), Err(TryRecvError::Empty));
-        tx3.send(()).unwrap();
-    }
-
-    #[test]
-    fn stress() {
-        const AMT: i32 = 10000;
-        let (tx1, rx1) = channel::<i32>();
-        let (tx2, rx2) = channel::<i32>();
-        let (tx3, rx3) = channel::<()>();
-
-        let _t = thread::spawn(move|| {
-            for i in 0..AMT {
-                if i % 2 == 0 {
-                    tx1.send(i).unwrap();
-                } else {
-                    tx2.send(i).unwrap();
-                }
-                rx3.recv().unwrap();
-            }
-        });
-
-        for i in 0..AMT {
-            select! {
-                i1 = rx1.recv() => { assert!(i % 2 == 0 && i == i1.unwrap()); },
-                i2 = rx2.recv() => { assert!(i % 2 == 1 && i == i2.unwrap()); }
-            }
-            tx3.send(()).unwrap();
-        }
-    }
-
-    #[allow(unused_must_use)]
-    #[test]
-    fn cloning() {
-        let (tx1, rx1) = channel::<i32>();
-        let (_tx2, rx2) = channel::<i32>();
-        let (tx3, rx3) = channel::<()>();
-
-        let _t = thread::spawn(move|| {
-            rx3.recv().unwrap();
-            tx1.clone();
-            assert_eq!(rx3.try_recv(), Err(TryRecvError::Empty));
-            tx1.send(2).unwrap();
-            rx3.recv().unwrap();
-        });
-
-        tx3.send(()).unwrap();
-        select! {
-            _i1 = rx1.recv() => {},
-            _i2 = rx2.recv() => panic!()
-        }
-        tx3.send(()).unwrap();
-    }
-
-    #[allow(unused_must_use)]
-    #[test]
-    fn cloning2() {
-        let (tx1, rx1) = channel::<i32>();
-        let (_tx2, rx2) = channel::<i32>();
-        let (tx3, rx3) = channel::<()>();
-
-        let _t = thread::spawn(move|| {
-            rx3.recv().unwrap();
-            tx1.clone();
-            assert_eq!(rx3.try_recv(), Err(TryRecvError::Empty));
-            tx1.send(2).unwrap();
-            rx3.recv().unwrap();
-        });
-
-        tx3.send(()).unwrap();
-        select! {
-            _i1 = rx1.recv() => {},
-            _i2 = rx2.recv() => panic!()
-        }
-        tx3.send(()).unwrap();
-    }
-
-    #[test]
-    fn cloning3() {
-        let (tx1, rx1) = channel::<()>();
-        let (tx2, rx2) = channel::<()>();
-        let (tx3, rx3) = channel::<()>();
-        let _t = thread::spawn(move|| {
-            let s = Select::new();
-            let mut h1 = s.handle(&rx1);
-            let mut h2 = s.handle(&rx2);
-            unsafe { h2.add(); }
-            unsafe { h1.add(); }
-            assert_eq!(s.wait(), h2.id);
-            tx3.send(()).unwrap();
-        });
-
-        for _ in 0..1000 { thread::yield_now(); }
-        drop(tx1.clone());
-        tx2.send(()).unwrap();
-        rx3.recv().unwrap();
-    }
-
-    #[test]
-    fn preflight1() {
-        let (tx, rx) = channel();
-        tx.send(()).unwrap();
-        select! {
-            _n = rx.recv() => {}
-        }
-    }
-
-    #[test]
-    fn preflight2() {
-        let (tx, rx) = channel();
-        tx.send(()).unwrap();
-        tx.send(()).unwrap();
-        select! {
-            _n = rx.recv() => {}
-        }
-    }
-
-    #[test]
-    fn preflight3() {
-        let (tx, rx) = channel();
-        drop(tx.clone());
-        tx.send(()).unwrap();
-        select! {
-            _n = rx.recv() => {}
-        }
-    }
-
-    #[test]
-    fn preflight4() {
-        let (tx, rx) = channel();
-        tx.send(()).unwrap();
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn preflight5() {
-        let (tx, rx) = channel();
-        tx.send(()).unwrap();
-        tx.send(()).unwrap();
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn preflight6() {
-        let (tx, rx) = channel();
-        drop(tx.clone());
-        tx.send(()).unwrap();
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn preflight7() {
-        let (tx, rx) = channel::<()>();
-        drop(tx);
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn preflight8() {
-        let (tx, rx) = channel();
-        tx.send(()).unwrap();
-        drop(tx);
-        rx.recv().unwrap();
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn preflight9() {
-        let (tx, rx) = channel();
-        drop(tx.clone());
-        tx.send(()).unwrap();
-        drop(tx);
-        rx.recv().unwrap();
-        let s = Select::new();
-        let mut h = s.handle(&rx);
-        unsafe { h.add(); }
-        assert_eq!(s.wait2(false), h.id);
-    }
-
-    #[test]
-    fn oneshot_data_waiting() {
-        let (tx1, rx1) = channel();
-        let (tx2, rx2) = channel();
-        let _t = thread::spawn(move|| {
-            select! {
-                _n = rx1.recv() => {}
-            }
-            tx2.send(()).unwrap();
-        });
-
-        for _ in 0..100 { thread::yield_now() }
-        tx1.send(()).unwrap();
-        rx2.recv().unwrap();
-    }
-
-    #[test]
-    fn stream_data_waiting() {
-        let (tx1, rx1) = channel();
-        let (tx2, rx2) = channel();
-        tx1.send(()).unwrap();
-        tx1.send(()).unwrap();
-        rx1.recv().unwrap();
-        rx1.recv().unwrap();
-        let _t = thread::spawn(move|| {
-            select! {
-                _n = rx1.recv() => {}
-            }
-            tx2.send(()).unwrap();
-        });
-
-        for _ in 0..100 { thread::yield_now() }
-        tx1.send(()).unwrap();
-        rx2.recv().unwrap();
-    }
-
-    #[test]
-    fn shared_data_waiting() {
-        let (tx1, rx1) = channel();
-        let (tx2, rx2) = channel();
-        drop(tx1.clone());
-        tx1.send(()).unwrap();
-        rx1.recv().unwrap();
-        let _t = thread::spawn(move|| {
-            select! {
-                _n = rx1.recv() => {}
-            }
-            tx2.send(()).unwrap();
-        });
-
-        for _ in 0..100 { thread::yield_now() }
-        tx1.send(()).unwrap();
-        rx2.recv().unwrap();
-    }
-
-    #[test]
-    fn sync1() {
-        let (tx, rx) = sync_channel::<i32>(1);
-        tx.send(1).unwrap();
-        select! {
-            n = rx.recv() => { assert_eq!(n.unwrap(), 1); }
-        }
-    }
-
-    #[test]
-    fn sync2() {
-        let (tx, rx) = sync_channel::<i32>(0);
-        let _t = thread::spawn(move|| {
-            for _ in 0..100 { thread::yield_now() }
-            tx.send(1).unwrap();
-        });
-        select! {
-            n = rx.recv() => { assert_eq!(n.unwrap(), 1); }
-        }
-    }
-
-    #[test]
-    fn sync3() {
-        let (tx1, rx1) = sync_channel::<i32>(0);
-        let (tx2, rx2): (Sender<i32>, Receiver<i32>) = channel();
-        let _t = thread::spawn(move|| { tx1.send(1).unwrap(); });
-        let _t = thread::spawn(move|| { tx2.send(2).unwrap(); });
-        select! {
-            n = rx1.recv() => {
-                let n = n.unwrap();
-                assert_eq!(n, 1);
-                assert_eq!(rx2.recv().unwrap(), 2);
-            },
-            n = rx2.recv() => {
-                let n = n.unwrap();
-                assert_eq!(n, 2);
-                assert_eq!(rx1.recv().unwrap(), 1);
-            }
-        }
-    }
-}
diff --git a/src/libstd/sync/mpsc/select_tests.rs b/src/libstd/sync/mpsc/select_tests.rs
new file mode 100644
index 0000000000000..be048511caaec
--- /dev/null
+++ b/src/libstd/sync/mpsc/select_tests.rs
@@ -0,0 +1,413 @@
+#![allow(unused_imports)]
+
+/// This file exists to hack around https://github.com/rust-lang/rust/issues/47238
+
+use thread;
+use sync::mpsc::*;
+
+// Don't use the libstd version so we can pull in the right Select structure
+// (std::comm points at the wrong one)
+macro_rules! select {
+    (
+        $($name:pat = $rx:ident.$meth:ident() => $code:expr),+
+    ) => ({
+        let sel = Select::new();
+        $( let mut $rx = sel.handle(&$rx); )+
+        unsafe {
+            $( $rx.add(); )+
+        }
+        let ret = sel.wait();
+        $( if ret == $rx.id() { let $name = $rx.$meth(); $code } else )+
+        { unreachable!() }
+    })
+}
+
+#[test]
+fn smoke() {
+    let (tx1, rx1) = channel::<i32>();
+    let (tx2, rx2) = channel::<i32>();
+    tx1.send(1).unwrap();
+    select! {
+        foo = rx1.recv() => { assert_eq!(foo.unwrap(), 1); },
+        _bar = rx2.recv() => { panic!() }
+    }
+    tx2.send(2).unwrap();
+    select! {
+        _foo = rx1.recv() => { panic!() },
+        bar = rx2.recv() => { assert_eq!(bar.unwrap(), 2) }
+    }
+    drop(tx1);
+    select! {
+        foo = rx1.recv() => { assert!(foo.is_err()); },
+        _bar = rx2.recv() => { panic!() }
+    }
+    drop(tx2);
+    select! {
+        bar = rx2.recv() => { assert!(bar.is_err()); }
+    }
+}
+
+#[test]
+fn smoke2() {
+    let (_tx1, rx1) = channel::<i32>();
+    let (_tx2, rx2) = channel::<i32>();
+    let (_tx3, rx3) = channel::<i32>();
+    let (_tx4, rx4) = channel::<i32>();
+    let (tx5, rx5) = channel::<i32>();
+    tx5.send(4).unwrap();
+    select! {
+        _foo = rx1.recv() => { panic!("1") },
+        _foo = rx2.recv() => { panic!("2") },
+        _foo = rx3.recv() => { panic!("3") },
+        _foo = rx4.recv() => { panic!("4") },
+        foo = rx5.recv() => { assert_eq!(foo.unwrap(), 4); }
+    }
+}
+
+#[test]
+fn closed() {
+    let (_tx1, rx1) = channel::<i32>();
+    let (tx2, rx2) = channel::<i32>();
+    drop(tx2);
+
+    select! {
+        _a1 = rx1.recv() => { panic!() },
+        a2 = rx2.recv() => { assert!(a2.is_err()); }
+    }
+}
+
+#[test]
+fn unblocks() {
+    let (tx1, rx1) = channel::<i32>();
+    let (_tx2, rx2) = channel::<i32>();
+    let (tx3, rx3) = channel::<i32>();
+
+    let _t = thread::spawn(move|| {
+        for _ in 0..20 { thread::yield_now(); }
+        tx1.send(1).unwrap();
+        rx3.recv().unwrap();
+        for _ in 0..20 { thread::yield_now(); }
+    });
+
+    select! {
+        a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
+        _b = rx2.recv() => { panic!() }
+    }
+    tx3.send(1).unwrap();
+    select! {
+        a = rx1.recv() => { assert!(a.is_err()) },
+        _b = rx2.recv() => { panic!() }
+    }
+}
+
+#[test]
+fn both_ready() {
+    let (tx1, rx1) = channel::<i32>();
+    let (tx2, rx2) = channel::<i32>();
+    let (tx3, rx3) = channel::<()>();
+
+    let _t = thread::spawn(move|| {
+        for _ in 0..20 { thread::yield_now(); }
+        tx1.send(1).unwrap();
+        tx2.send(2).unwrap();
+        rx3.recv().unwrap();
+    });
+
+    select! {
+        a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
+        a = rx2.recv() => { assert_eq!(a.unwrap(), 2); }
+    }
+    select! {
+        a = rx1.recv() => { assert_eq!(a.unwrap(), 1); },
+        a = rx2.recv() => { assert_eq!(a.unwrap(), 2); }
+    }
+    assert_eq!(rx1.try_recv(), Err(TryRecvError::Empty));
+    assert_eq!(rx2.try_recv(), Err(TryRecvError::Empty));
+    tx3.send(()).unwrap();
+}
+
+#[test]
+fn stress() {
+    const AMT: i32 = 10000;
+    let (tx1, rx1) = channel::<i32>();
+    let (tx2, rx2) = channel::<i32>();
+    let (tx3, rx3) = channel::<()>();
+
+    let _t = thread::spawn(move|| {
+        for i in 0..AMT {
+            if i % 2 == 0 {
+                tx1.send(i).unwrap();
+            } else {
+                tx2.send(i).unwrap();
+            }
+            rx3.recv().unwrap();
+        }
+    });
+
+    for i in 0..AMT {
+        select! {
+            i1 = rx1.recv() => { assert!(i % 2 == 0 && i == i1.unwrap()); },
+            i2 = rx2.recv() => { assert!(i % 2 == 1 && i == i2.unwrap()); }
+        }
+        tx3.send(()).unwrap();
+    }
+}
+
+#[allow(unused_must_use)]
+#[test]
+fn cloning() {
+    let (tx1, rx1) = channel::<i32>();
+    let (_tx2, rx2) = channel::<i32>();
+    let (tx3, rx3) = channel::<()>();
+
+    let _t = thread::spawn(move|| {
+        rx3.recv().unwrap();
+        tx1.clone();
+        assert_eq!(rx3.try_recv(), Err(TryRecvError::Empty));
+        tx1.send(2).unwrap();
+        rx3.recv().unwrap();
+    });
+
+    tx3.send(()).unwrap();
+    select! {
+        _i1 = rx1.recv() => {},
+        _i2 = rx2.recv() => panic!()
+    }
+    tx3.send(()).unwrap();
+}
+
+#[allow(unused_must_use)]
+#[test]
+fn cloning2() {
+    let (tx1, rx1) = channel::<i32>();
+    let (_tx2, rx2) = channel::<i32>();
+    let (tx3, rx3) = channel::<()>();
+
+    let _t = thread::spawn(move|| {
+        rx3.recv().unwrap();
+        tx1.clone();
+        assert_eq!(rx3.try_recv(), Err(TryRecvError::Empty));
+        tx1.send(2).unwrap();
+        rx3.recv().unwrap();
+    });
+
+    tx3.send(()).unwrap();
+    select! {
+        _i1 = rx1.recv() => {},
+        _i2 = rx2.recv() => panic!()
+    }
+    tx3.send(()).unwrap();
+}
+
+#[test]
+fn cloning3() {
+    let (tx1, rx1) = channel::<()>();
+    let (tx2, rx2) = channel::<()>();
+    let (tx3, rx3) = channel::<()>();
+    let _t = thread::spawn(move|| {
+        let s = Select::new();
+        let mut h1 = s.handle(&rx1);
+        let mut h2 = s.handle(&rx2);
+        unsafe { h2.add(); }
+        unsafe { h1.add(); }
+        assert_eq!(s.wait(), h2.id());
+        tx3.send(()).unwrap();
+    });
+
+    for _ in 0..1000 { thread::yield_now(); }
+    drop(tx1.clone());
+    tx2.send(()).unwrap();
+    rx3.recv().unwrap();
+}
+
+#[test]
+fn preflight1() {
+    let (tx, rx) = channel();
+    tx.send(()).unwrap();
+    select! {
+        _n = rx.recv() => {}
+    }
+}
+
+#[test]
+fn preflight2() {
+    let (tx, rx) = channel();
+    tx.send(()).unwrap();
+    tx.send(()).unwrap();
+    select! {
+        _n = rx.recv() => {}
+    }
+}
+
+#[test]
+fn preflight3() {
+    let (tx, rx) = channel();
+    drop(tx.clone());
+    tx.send(()).unwrap();
+    select! {
+        _n = rx.recv() => {}
+    }
+}
+
+#[test]
+fn preflight4() {
+    let (tx, rx) = channel();
+    tx.send(()).unwrap();
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn preflight5() {
+    let (tx, rx) = channel();
+    tx.send(()).unwrap();
+    tx.send(()).unwrap();
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn preflight6() {
+    let (tx, rx) = channel();
+    drop(tx.clone());
+    tx.send(()).unwrap();
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn preflight7() {
+    let (tx, rx) = channel::<()>();
+    drop(tx);
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn preflight8() {
+    let (tx, rx) = channel();
+    tx.send(()).unwrap();
+    drop(tx);
+    rx.recv().unwrap();
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn preflight9() {
+    let (tx, rx) = channel();
+    drop(tx.clone());
+    tx.send(()).unwrap();
+    drop(tx);
+    rx.recv().unwrap();
+    let s = Select::new();
+    let mut h = s.handle(&rx);
+    unsafe { h.add(); }
+    assert_eq!(s.wait2(false), h.id());
+}
+
+#[test]
+fn oneshot_data_waiting() {
+    let (tx1, rx1) = channel();
+    let (tx2, rx2) = channel();
+    let _t = thread::spawn(move|| {
+        select! {
+            _n = rx1.recv() => {}
+        }
+        tx2.send(()).unwrap();
+    });
+
+    for _ in 0..100 { thread::yield_now() }
+    tx1.send(()).unwrap();
+    rx2.recv().unwrap();
+}
+
+#[test]
+fn stream_data_waiting() {
+    let (tx1, rx1) = channel();
+    let (tx2, rx2) = channel();
+    tx1.send(()).unwrap();
+    tx1.send(()).unwrap();
+    rx1.recv().unwrap();
+    rx1.recv().unwrap();
+    let _t = thread::spawn(move|| {
+        select! {
+            _n = rx1.recv() => {}
+        }
+        tx2.send(()).unwrap();
+    });
+
+    for _ in 0..100 { thread::yield_now() }
+    tx1.send(()).unwrap();
+    rx2.recv().unwrap();
+}
+
+#[test]
+fn shared_data_waiting() {
+    let (tx1, rx1) = channel();
+    let (tx2, rx2) = channel();
+    drop(tx1.clone());
+    tx1.send(()).unwrap();
+    rx1.recv().unwrap();
+    let _t = thread::spawn(move|| {
+        select! {
+            _n = rx1.recv() => {}
+        }
+        tx2.send(()).unwrap();
+    });
+
+    for _ in 0..100 { thread::yield_now() }
+    tx1.send(()).unwrap();
+    rx2.recv().unwrap();
+}
+
+#[test]
+fn sync1() {
+    let (tx, rx) = sync_channel::<i32>(1);
+    tx.send(1).unwrap();
+    select! {
+        n = rx.recv() => { assert_eq!(n.unwrap(), 1); }
+    }
+}
+
+#[test]
+fn sync2() {
+    let (tx, rx) = sync_channel::<i32>(0);
+    let _t = thread::spawn(move|| {
+        for _ in 0..100 { thread::yield_now() }
+        tx.send(1).unwrap();
+    });
+    select! {
+        n = rx.recv() => { assert_eq!(n.unwrap(), 1); }
+    }
+}
+
+#[test]
+fn sync3() {
+    let (tx1, rx1) = sync_channel::<i32>(0);
+    let (tx2, rx2): (Sender<i32>, Receiver<i32>) = channel();
+    let _t = thread::spawn(move|| { tx1.send(1).unwrap(); });
+    let _t = thread::spawn(move|| { tx2.send(2).unwrap(); });
+    select! {
+        n = rx1.recv() => {
+            let n = n.unwrap();
+            assert_eq!(n, 1);
+            assert_eq!(rx2.recv().unwrap(), 2);
+        },
+        n = rx2.recv() => {
+            let n = n.unwrap();
+            assert_eq!(n, 2);
+            assert_eq!(rx1.recv().unwrap(), 1);
+        }
+    }
+}
diff --git a/src/libstd/sync/mpsc/shared.rs b/src/libstd/sync/mpsc/shared.rs
index af538b75b701d..3da73ac0b822e 100644
--- a/src/libstd/sync/mpsc/shared.rs
+++ b/src/libstd/sync/mpsc/shared.rs
@@ -1,4 +1,4 @@
-/// Shared channels
+/// Shared channels.
 ///
 /// This is the flavor of channels which are not necessarily optimized for any
 /// particular use case, but are the most general in how they are used. Shared
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
index 856bb26042490..954867911a031 100644
--- a/src/libstd/sync/mutex.rs
+++ b/src/libstd/sync/mutex.rs
@@ -150,9 +150,9 @@ pub struct MutexGuard<'a, T: ?Sized + 'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> !Send for MutexGuard<'a, T> { }
+impl<T: ?Sized> !Send for MutexGuard<'_, T> { }
 #[stable(feature = "mutexguard", since = "1.19.0")]
-unsafe impl<'a, T: ?Sized + Sync> Sync for MutexGuard<'a, T> { }
+unsafe impl<T: ?Sized + Sync> Sync for MutexGuard<'_, T> { }
 
 impl<T> Mutex<T> {
     /// Creates a new mutex in an unlocked state ready for use.
@@ -335,7 +335,7 @@ impl<T: ?Sized> Mutex<T> {
     /// Returns a mutable reference to the underlying data.
     ///
     /// Since this call borrows the `Mutex` mutably, no actual locking needs to
-    /// take place---the mutable borrow statically guarantees no locks exist.
+    /// take place -- the mutable borrow statically guarantees no locks exist.
     ///
     /// # Errors
     ///
@@ -421,7 +421,7 @@ impl<'mutex, T: ?Sized> MutexGuard<'mutex, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'mutex, T: ?Sized> Deref for MutexGuard<'mutex, T> {
+impl<T: ?Sized> Deref for MutexGuard<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -430,14 +430,14 @@ impl<'mutex, T: ?Sized> Deref for MutexGuard<'mutex, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'mutex, T: ?Sized> DerefMut for MutexGuard<'mutex, T> {
+impl<T: ?Sized> DerefMut for MutexGuard<'_, T> {
     fn deref_mut(&mut self) -> &mut T {
         unsafe { &mut *self.__lock.data.get() }
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {
+impl<T: ?Sized> Drop for MutexGuard<'_, T> {
     #[inline]
     fn drop(&mut self) {
         unsafe {
@@ -448,16 +448,14 @@ impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'a, T> {
+impl<T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("MutexGuard")
-            .field("lock", &self.__lock)
-            .finish()
+        fmt::Debug::fmt(&**self, f)
     }
 }
 
 #[stable(feature = "std_guard_impls", since = "1.20.0")]
-impl<'a, T: ?Sized + fmt::Display> fmt::Display for MutexGuard<'a, T> {
+impl<T: ?Sized + fmt::Display> fmt::Display for MutexGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         (**self).fmt(f)
     }
diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index fcab2ffe1444c..e207d0170d7b8 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -228,7 +228,7 @@ impl Once {
     /// result in an immediate panic. If `f` panics, the `Once` will remain
     /// in a poison state. If `f` does _not_ panic, the `Once` will no
     /// longer be in a poison state and all future calls to `call_once` or
-    /// `call_one_force` will no-op.
+    /// `call_one_force` will be no-ops.
     ///
     /// The closure `f` is yielded a [`OnceState`] structure which can be used
     /// to query the poison status of the `Once`.
@@ -279,7 +279,7 @@ impl Once {
         });
     }
 
-    /// Returns true if some `call_once` call has completed
+    /// Returns `true` if some `call_once` call has completed
     /// successfully. Specifically, `is_completed` will return false in
     /// the following situations:
     ///   * `call_once` was not called at all,
@@ -436,7 +436,7 @@ impl fmt::Debug for Once {
     }
 }
 
-impl<'a> Drop for Finish<'a> {
+impl Drop for Finish<'_> {
     fn drop(&mut self) {
         // Swap out our state with however we finished. We should only ever see
         // an old state which was RUNNING.
@@ -465,7 +465,7 @@ impl<'a> Drop for Finish<'a> {
 }
 
 impl OnceState {
-    /// Returns whether the associated [`Once`] was poisoned prior to the
+    /// Returns `true` if the associated [`Once`] was poisoned prior to the
     /// invocation of the closure passed to [`call_once_force`].
     ///
     /// [`call_once_force`]: struct.Once.html#method.call_once_force
diff --git a/src/libstd/sync/rwlock.rs b/src/libstd/sync/rwlock.rs
index 7fbe0b8c19900..7f3cb4f72c7b5 100644
--- a/src/libstd/sync/rwlock.rs
+++ b/src/libstd/sync/rwlock.rs
@@ -91,10 +91,10 @@ pub struct RwLockReadGuard<'a, T: ?Sized + 'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> !Send for RwLockReadGuard<'a, T> {}
+impl<T: ?Sized> !Send for RwLockReadGuard<'_, T> {}
 
 #[stable(feature = "rwlock_guard_sync", since = "1.23.0")]
-unsafe impl<'a, T: ?Sized + Sync> Sync for RwLockReadGuard<'a, T> {}
+unsafe impl<T: ?Sized + Sync> Sync for RwLockReadGuard<'_, T> {}
 
 /// RAII structure used to release the exclusive write access of a lock when
 /// dropped.
@@ -113,10 +113,10 @@ pub struct RwLockWriteGuard<'a, T: ?Sized + 'a> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> !Send for RwLockWriteGuard<'a, T> {}
+impl<T: ?Sized> !Send for RwLockWriteGuard<'_, T> {}
 
 #[stable(feature = "rwlock_guard_sync", since = "1.23.0")]
-unsafe impl<'a, T: ?Sized + Sync> Sync for RwLockWriteGuard<'a, T> {}
+unsafe impl<T: ?Sized + Sync> Sync for RwLockWriteGuard<'_, T> {}
 
 impl<T> RwLock<T> {
     /// Creates a new instance of an `RwLock<T>` which is unlocked.
@@ -314,7 +314,7 @@ impl<T: ?Sized> RwLock<T> {
     /// Determines whether the lock is poisoned.
     ///
     /// If another thread is active, the lock can still become poisoned at any
-    /// time.  You should not trust a `false` value for program correctness
+    /// time. You should not trust a `false` value for program correctness
     /// without additional synchronization.
     ///
     /// # Examples
@@ -384,7 +384,7 @@ impl<T: ?Sized> RwLock<T> {
     /// Returns a mutable reference to the underlying data.
     ///
     /// Since this call borrows the `RwLock` mutably, no actual locking needs to
-    /// take place---the mutable borrow statically guarantees no locks exist.
+    /// take place -- the mutable borrow statically guarantees no locks exist.
     ///
     /// # Errors
     ///
@@ -480,7 +480,7 @@ impl<'rwlock, T: ?Sized> RwLockWriteGuard<'rwlock, T> {
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T: fmt::Debug> fmt::Debug for RwLockReadGuard<'a, T> {
+impl<T: fmt::Debug> fmt::Debug for RwLockReadGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RwLockReadGuard")
             .field("lock", &self.__lock)
@@ -489,14 +489,14 @@ impl<'a, T: fmt::Debug> fmt::Debug for RwLockReadGuard<'a, T> {
 }
 
 #[stable(feature = "std_guard_impls", since = "1.20.0")]
-impl<'a, T: ?Sized + fmt::Display> fmt::Display for RwLockReadGuard<'a, T> {
+impl<T: ?Sized + fmt::Display> fmt::Display for RwLockReadGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         (**self).fmt(f)
     }
 }
 
 #[stable(feature = "std_debug", since = "1.16.0")]
-impl<'a, T: fmt::Debug> fmt::Debug for RwLockWriteGuard<'a, T> {
+impl<T: fmt::Debug> fmt::Debug for RwLockWriteGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("RwLockWriteGuard")
             .field("lock", &self.__lock)
@@ -505,14 +505,14 @@ impl<'a, T: fmt::Debug> fmt::Debug for RwLockWriteGuard<'a, T> {
 }
 
 #[stable(feature = "std_guard_impls", since = "1.20.0")]
-impl<'a, T: ?Sized + fmt::Display> fmt::Display for RwLockWriteGuard<'a, T> {
+impl<T: ?Sized + fmt::Display> fmt::Display for RwLockWriteGuard<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         (**self).fmt(f)
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'rwlock, T: ?Sized> Deref for RwLockReadGuard<'rwlock, T> {
+impl<T: ?Sized> Deref for RwLockReadGuard<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -521,7 +521,7 @@ impl<'rwlock, T: ?Sized> Deref for RwLockReadGuard<'rwlock, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'rwlock, T: ?Sized> Deref for RwLockWriteGuard<'rwlock, T> {
+impl<T: ?Sized> Deref for RwLockWriteGuard<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -530,21 +530,21 @@ impl<'rwlock, T: ?Sized> Deref for RwLockWriteGuard<'rwlock, T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'rwlock, T: ?Sized> DerefMut for RwLockWriteGuard<'rwlock, T> {
+impl<T: ?Sized> DerefMut for RwLockWriteGuard<'_, T> {
     fn deref_mut(&mut self) -> &mut T {
         unsafe { &mut *self.__lock.data.get() }
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> Drop for RwLockReadGuard<'a, T> {
+impl<T: ?Sized> Drop for RwLockReadGuard<'_, T> {
     fn drop(&mut self) {
         unsafe { self.__lock.inner.read_unlock(); }
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T: ?Sized> Drop for RwLockWriteGuard<'a, T> {
+impl<T: ?Sized> Drop for RwLockWriteGuard<'_, T> {
     fn drop(&mut self) {
         self.__lock.poison.done(&self.__poison);
         unsafe { self.__lock.inner.write_unlock(); }
diff --git a/src/libstd/sys/cloudabi/abi/cloudabi.rs b/src/libstd/sys/cloudabi/abi/cloudabi.rs
index 0bf8c2d599813..83d45b3547bc2 100644
--- a/src/libstd/sys/cloudabi/abi/cloudabi.rs
+++ b/src/libstd/sys/cloudabi/abi/cloudabi.rs
@@ -673,11 +673,11 @@ bitflags! {
   /// Methods of synchronizing memory with physical storage.
   #[repr(C)]
   pub struct msflags: u8 {
-    /// Perform asynchronous writes.
+    /// Performs asynchronous writes.
     const ASYNC      = 0x01;
-    /// Invalidate cached data.
+    /// Invalidates cached data.
     const INVALIDATE = 0x02;
-    /// Perform synchronous writes.
+    /// Performs synchronous writes.
     const SYNC       = 0x04;
   }
 }
@@ -1750,11 +1750,9 @@ fn tcb_layout_test_64() {
 
 /// Entry point for additionally created threads.
 ///
-/// **tid**:
-/// Thread ID of the current thread.
+/// `tid`: thread ID of the current thread.
 ///
-/// **aux**:
-/// Copy of the value stored in
+/// `aux`: copy of the value stored in
 /// [`threadattr.argument`](struct.threadattr.html#structfield.argument).
 pub type threadentry = unsafe extern "C" fn(
   tid: tid,
@@ -2590,7 +2588,7 @@ pub unsafe fn mem_map(addr_: *mut (), len_: usize, prot_: mprot, flags_: mflags,
   cloudabi_sys_mem_map(addr_, len_, prot_, flags_, fd_, off_, mem_)
 }
 
-/// Change the protection of a memory mapping.
+/// Changes the protection of a memory mapping.
 ///
 /// ## Parameters
 ///
@@ -2604,7 +2602,7 @@ pub unsafe fn mem_protect(mapping_: &mut [u8], prot_: mprot) -> errno {
   cloudabi_sys_mem_protect(mapping_.as_mut_ptr() as *mut (), mapping_.len(), prot_)
 }
 
-/// Synchronize a region of memory with its physical storage.
+/// Synchronizes a region of memory with its physical storage.
 ///
 /// ## Parameters
 ///
diff --git a/src/libstd/sys/mod.rs b/src/libstd/sys/mod.rs
index f398a2a6225ce..0a56f4fad6d15 100644
--- a/src/libstd/sys/mod.rs
+++ b/src/libstd/sys/mod.rs
@@ -1,4 +1,4 @@
-//! Platform-dependent platform abstraction
+//! Platform-dependent platform abstraction.
 //!
 //! The `std::sys` module is the abstracted interface through which
 //! `std` talks to the underlying operating system. It has different
@@ -54,6 +54,7 @@ cfg_if! {
 cfg_if! {
     if #[cfg(any(unix, target_os = "redox"))] {
         // On unix we'll document what's already available
+        #[stable(feature = "rust1", since = "1.0.0")]
         pub use self::ext as unix_ext;
     } else if #[cfg(any(target_os = "cloudabi",
                         target_arch = "wasm32",
@@ -77,6 +78,7 @@ cfg_if! {
     if #[cfg(windows)] {
         // On windows we'll just be documenting what's already available
         #[allow(missing_docs)]
+        #[stable(feature = "rust1", since = "1.0.0")]
         pub use self::ext as windows_ext;
     } else if #[cfg(any(target_os = "cloudabi",
                         target_arch = "wasm32",
diff --git a/src/libstd/sys/redox/ext/fs.rs b/src/libstd/sys/redox/ext/fs.rs
index 04edfd6851dde..8b81273f201cf 100644
--- a/src/libstd/sys/redox/ext/fs.rs
+++ b/src/libstd/sys/redox/ext/fs.rs
@@ -117,7 +117,7 @@ pub trait OpenOptionsExt {
     #[stable(feature = "fs_ext", since = "1.1.0")]
     fn mode(&mut self, mode: u32) -> &mut Self;
 
-    /// Pass custom flags to the `flags` argument of `open`.
+    /// Passes custom flags to the `flags` argument of `open`.
     ///
     /// The bits that define the access mode are masked out with `O_ACCMODE`, to
     /// ensure they do not interfere with the access mode set by Rusts options.
@@ -287,9 +287,9 @@ impl FileTypeExt for fs::FileType {
 /// # Note
 ///
 /// On Windows, you must specify whether a symbolic link points to a file
-/// or directory.  Use `os::windows::fs::symlink_file` to create a
+/// or directory. Use `os::windows::fs::symlink_file` to create a
 /// symbolic link to a file, or `os::windows::fs::symlink_dir` to create a
-/// symbolic link to a directory.  Additionally, the process must have
+/// symbolic link to a directory. Additionally, the process must have
 /// `SeCreateSymbolicLinkPrivilege` in order to be able to create a
 /// symbolic link.
 ///
diff --git a/src/libstd/sys/redox/ext/net.rs b/src/libstd/sys/redox/ext/net.rs
index 76c68829b7f1b..7411b8e068f64 100644
--- a/src/libstd/sys/redox/ext/net.rs
+++ b/src/libstd/sys/redox/ext/net.rs
@@ -60,7 +60,7 @@ impl SocketAddr {
         None
     }
 
-    /// Returns true if and only if the address is unnamed.
+    /// Returns `true` if the address is unnamed.
     ///
     /// # Examples
     ///
@@ -374,7 +374,7 @@ impl UnixStream {
     /// ```
     ///
     /// # Platform specific
-    /// On Redox this always returns None.
+    /// On Redox this always returns `None`.
     #[stable(feature = "unix_socket_redox", since = "1.29")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         Ok(None)
@@ -635,7 +635,7 @@ impl UnixListener {
     /// ```
     ///
     /// # Platform specific
-    /// On Redox this always returns None.
+    /// On Redox this always returns `None`.
     #[stable(feature = "unix_socket_redox", since = "1.29")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         Ok(None)
diff --git a/src/libstd/sys/redox/ext/process.rs b/src/libstd/sys/redox/ext/process.rs
index 941fba8755b4a..020075531dd0e 100644
--- a/src/libstd/sys/redox/ext/process.rs
+++ b/src/libstd/sys/redox/ext/process.rs
@@ -13,13 +13,13 @@ use sys_common::{AsInnerMut, AsInner, FromInner, IntoInner};
 /// [`process::Command`]: ../../../../std/process/struct.Command.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait CommandExt {
-    /// Sets the child process's user id. This translates to a
+    /// Sets the child process's user ID. This translates to a
     /// `setuid` call in the child process. Failure in the `setuid`
     /// call will cause the spawn to fail.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn uid(&mut self, id: u32) -> &mut process::Command;
 
-    /// Similar to `uid`, but sets the group id of the child process. This has
+    /// Similar to `uid`, but sets the group ID of the child process. This has
     /// the same semantics as the `uid` field.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn gid(&mut self, id: u32) -> &mut process::Command;
@@ -36,7 +36,7 @@ pub trait CommandExt {
     /// will be called and the spawn operation will immediately return with a
     /// failure.
     ///
-    /// # Notes
+    /// # Notes and Safety
     ///
     /// This closure will be run in the context of the child process after a
     /// `fork`. This primarily means that any modifications made to memory on
@@ -45,12 +45,32 @@ pub trait CommandExt {
     /// like `malloc` or acquiring a mutex are not guaranteed to work (due to
     /// other threads perhaps still running when the `fork` was run).
     ///
+    /// This also means that all resources such as file descriptors and
+    /// memory-mapped regions got duplicated. It is your responsibility to make
+    /// sure that the closure does not violate library invariants by making
+    /// invalid use of these duplicates.
+    ///
     /// When this closure is run, aspects such as the stdio file descriptors and
     /// working directory have successfully been changed, so output to these
     /// locations may not appear where intended.
+    #[stable(feature = "process_pre_exec", since = "1.34.0")]
+    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
+        where F: FnMut() -> io::Result<()> + Send + Sync + 'static;
+
+    /// Schedules a closure to be run just before the `exec` function is
+    /// invoked.
+    ///
+    /// This method is stable and usable, but it should be unsafe. To fix
+    /// that, it got deprecated in favor of the unsafe [`pre_exec`].
+    ///
+    /// [`pre_exec`]: #tymethod.pre_exec
     #[stable(feature = "process_exec", since = "1.15.0")]
+    #[rustc_deprecated(since = "1.37.0", reason = "should be unsafe, use `pre_exec` instead")]
     fn before_exec<F>(&mut self, f: F) -> &mut process::Command
-        where F: FnMut() -> io::Result<()> + Send + Sync + 'static;
+        where F: FnMut() -> io::Result<()> + Send + Sync + 'static
+    {
+        unsafe { self.pre_exec(f) }
+    }
 
     /// Performs all the required setup by this `Command`, followed by calling
     /// the `execvp` syscall.
@@ -87,10 +107,10 @@ impl CommandExt for process::Command {
         self
     }
 
-    fn before_exec<F>(&mut self, f: F) -> &mut process::Command
+    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
         where F: FnMut() -> io::Result<()> + Send + Sync + 'static
     {
-        self.as_inner_mut().before_exec(Box::new(f));
+        self.as_inner_mut().pre_exec(Box::new(f));
         self
     }
 
diff --git a/src/libstd/sys/redox/mutex.rs b/src/libstd/sys/redox/mutex.rs
index 42424da858fbc..bf39cc485911b 100644
--- a/src/libstd/sys/redox/mutex.rs
+++ b/src/libstd/sys/redox/mutex.rs
@@ -50,7 +50,7 @@ pub struct Mutex {
 }
 
 impl Mutex {
-    /// Create a new mutex.
+    /// Creates a new mutex.
     pub const fn new() -> Self {
         Mutex {
             lock: UnsafeCell::new(0),
diff --git a/src/libstd/sys/redox/process.rs b/src/libstd/sys/redox/process.rs
index 4199ab98cf17e..81af8eb553d00 100644
--- a/src/libstd/sys/redox/process.rs
+++ b/src/libstd/sys/redox/process.rs
@@ -116,8 +116,10 @@ impl Command {
         self.gid = Some(id);
     }
 
-    pub fn before_exec(&mut self,
-                       f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>) {
+    pub unsafe fn pre_exec(
+        &mut self,
+        f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>,
+    ) {
         self.closures.push(f);
     }
 
@@ -561,7 +563,7 @@ impl ExitCode {
     }
 }
 
-/// The unique id of the process (this should never be negative).
+/// The unique ID of the process (this should never be negative).
 pub struct Process {
     pid: usize,
     status: Option<ExitStatus>,
diff --git a/src/libstd/sys/redox/syscall/call.rs b/src/libstd/sys/redox/syscall/call.rs
index b9e2b476cecc0..b9abb48a8d368 100644
--- a/src/libstd/sys/redox/syscall/call.rs
+++ b/src/libstd/sys/redox/syscall/call.rs
@@ -25,7 +25,7 @@ pub unsafe fn brk(addr: usize) -> Result<usize> {
     syscall1(SYS_BRK, addr)
 }
 
-/// Change the process's working directory
+/// Changes the process's working directory.
 ///
 /// This function will attempt to set the process's working directory to `path`, which can be
 /// either a relative, scheme relative, or absolute path.
@@ -47,90 +47,90 @@ pub fn chmod<T: AsRef<[u8]>>(path: T, mode: usize) -> Result<usize> {
     unsafe { syscall3(SYS_CHMOD, path.as_ref().as_ptr() as usize, path.as_ref().len(), mode) }
 }
 
-/// Produce a fork of the current process, or a new process thread
+/// Produces a fork of the current process, or a new process thread.
 pub unsafe fn clone(flags: usize) -> Result<usize> {
     syscall1_clobber(SYS_CLONE, flags)
 }
 
-/// Close a file
+/// Closes a file.
 pub fn close(fd: usize) -> Result<usize> {
     unsafe { syscall1(SYS_CLOSE, fd) }
 }
 
-/// Get the current system time
+/// Gets the current system time.
 pub fn clock_gettime(clock: usize, tp: &mut TimeSpec) -> Result<usize> {
     unsafe { syscall2(SYS_CLOCK_GETTIME, clock, tp as *mut TimeSpec as usize) }
 }
 
-/// Copy and transform a file descriptor
+/// Copies and transforms a file descriptor.
 pub fn dup(fd: usize, buf: &[u8]) -> Result<usize> {
     unsafe { syscall3(SYS_DUP, fd, buf.as_ptr() as usize, buf.len()) }
 }
 
-/// Copy and transform a file descriptor
+/// Copies and transforms a file descriptor.
 pub fn dup2(fd: usize, newfd: usize, buf: &[u8]) -> Result<usize> {
     unsafe { syscall4(SYS_DUP2, fd, newfd, buf.as_ptr() as usize, buf.len()) }
 }
 
-/// Exit the current process
+/// Exits the current process.
 pub fn exit(status: usize) -> Result<usize> {
     unsafe { syscall1(SYS_EXIT, status) }
 }
 
-/// Change file permissions
+/// Changes file permissions.
 pub fn fchmod(fd: usize, mode: u16) -> Result<usize> {
     unsafe { syscall2(SYS_FCHMOD, fd, mode as usize) }
 
 }
 
-/// Change file ownership
+/// Changes file ownership.
 pub fn fchown(fd: usize, uid: u32, gid: u32) -> Result<usize> {
     unsafe { syscall3(SYS_FCHOWN, fd, uid as usize, gid as usize) }
 
 }
 
-/// Change file descriptor flags
+/// Changes file descriptor flags.
 pub fn fcntl(fd: usize, cmd: usize, arg: usize) -> Result<usize> {
     unsafe { syscall3(SYS_FCNTL, fd, cmd, arg) }
 }
 
-/// Replace the current process with a new executable
+/// Replaces the current process with a new executable.
 pub fn fexec(fd: usize, args: &[[usize; 2]], vars: &[[usize; 2]]) -> Result<usize> {
     unsafe { syscall5(SYS_FEXEC, fd, args.as_ptr() as usize, args.len(),
                       vars.as_ptr() as usize, vars.len()) }
 }
 
-/// Map a file into memory
+/// Maps a file into memory.
 pub unsafe fn fmap(fd: usize, offset: usize, size: usize) -> Result<usize> {
     syscall3(SYS_FMAP, fd, offset, size)
 }
 
-/// Unmap a memory-mapped file
+/// Unmaps a memory-mapped file.
 pub unsafe fn funmap(addr: usize) -> Result<usize> {
     syscall1(SYS_FUNMAP, addr)
 }
 
-/// Retrieve the canonical path of a file
+/// Retrieves the canonical path of a file.
 pub fn fpath(fd: usize, buf: &mut [u8]) -> Result<usize> {
     unsafe { syscall3(SYS_FPATH, fd, buf.as_mut_ptr() as usize, buf.len()) }
 }
 
-/// Rename a file
+/// Renames a file.
 pub fn frename<T: AsRef<[u8]>>(fd: usize, path: T) -> Result<usize> {
     unsafe { syscall3(SYS_FRENAME, fd, path.as_ref().as_ptr() as usize, path.as_ref().len()) }
 }
 
-/// Get metadata about a file
+/// Gets metadata about a file.
 pub fn fstat(fd: usize, stat: &mut Stat) -> Result<usize> {
     unsafe { syscall3(SYS_FSTAT, fd, stat as *mut Stat as usize, mem::size_of::<Stat>()) }
 }
 
-/// Get metadata about a filesystem
+/// Gets metadata about a filesystem.
 pub fn fstatvfs(fd: usize, stat: &mut StatVfs) -> Result<usize> {
     unsafe { syscall3(SYS_FSTATVFS, fd, stat as *mut StatVfs as usize, mem::size_of::<StatVfs>()) }
 }
 
-/// Sync a file descriptor to its underlying medium
+/// Syncs a file descriptor to its underlying medium.
 pub fn fsync(fd: usize) -> Result<usize> {
     unsafe { syscall1(SYS_FSYNC, fd) }
 }
@@ -152,113 +152,113 @@ pub unsafe fn futex(addr: *mut i32, op: usize, val: i32, val2: usize, addr2: *mu
     syscall5(SYS_FUTEX, addr as usize, op, (val as isize) as usize, val2, addr2 as usize)
 }
 
-/// Get the current working directory
+/// Gets the current working directory.
 pub fn getcwd(buf: &mut [u8]) -> Result<usize> {
     unsafe { syscall2(SYS_GETCWD, buf.as_mut_ptr() as usize, buf.len()) }
 }
 
-/// Get the effective group ID
+/// Gets the effective group ID.
 pub fn getegid() -> Result<usize> {
     unsafe { syscall0(SYS_GETEGID) }
 }
 
-/// Get the effective namespace
+/// Gets the effective namespace.
 pub fn getens() -> Result<usize> {
     unsafe { syscall0(SYS_GETENS) }
 }
 
-/// Get the effective user ID
+/// Gets the effective user ID.
 pub fn geteuid() -> Result<usize> {
     unsafe { syscall0(SYS_GETEUID) }
 }
 
-/// Get the current group ID
+/// Gets the current group ID.
 pub fn getgid() -> Result<usize> {
     unsafe { syscall0(SYS_GETGID) }
 }
 
-/// Get the current namespace
+/// Gets the current namespace.
 pub fn getns() -> Result<usize> {
     unsafe { syscall0(SYS_GETNS) }
 }
 
-/// Get the current process ID
+/// Gets the current process ID.
 pub fn getpid() -> Result<usize> {
     unsafe { syscall0(SYS_GETPID) }
 }
 
-/// Get the process group ID
+/// Gets the process group ID.
 pub fn getpgid(pid: usize) -> Result<usize> {
     unsafe { syscall1(SYS_GETPGID, pid) }
 }
 
-/// Get the parent process ID
+/// Gets the parent process ID.
 pub fn getppid() -> Result<usize> {
     unsafe { syscall0(SYS_GETPPID) }
 }
 
-/// Get the current user ID
+/// Gets the current user ID.
 pub fn getuid() -> Result<usize> {
     unsafe { syscall0(SYS_GETUID) }
 }
 
-/// Set the I/O privilege level
+/// Sets the I/O privilege level
 pub unsafe fn iopl(level: usize) -> Result<usize> {
     syscall1(SYS_IOPL, level)
 }
 
-/// Send a signal `sig` to the process identified by `pid`
+/// Sends a signal `sig` to the process identified by `pid`.
 pub fn kill(pid: usize, sig: usize) -> Result<usize> {
     unsafe { syscall2(SYS_KILL, pid, sig) }
 }
 
-/// Create a link to a file
+/// Creates a link to a file.
 pub unsafe fn link(old: *const u8, new: *const u8) -> Result<usize> {
     syscall2(SYS_LINK, old as usize, new as usize)
 }
 
-/// Seek to `offset` bytes in a file descriptor
+/// Seeks to `offset` bytes in a file descriptor.
 pub fn lseek(fd: usize, offset: isize, whence: usize) -> Result<usize> {
     unsafe { syscall3(SYS_LSEEK, fd, offset as usize, whence) }
 }
 
-/// Make a new scheme namespace
+/// Makes a new scheme namespace.
 pub fn mkns(schemes: &[[usize; 2]]) -> Result<usize> {
     unsafe { syscall2(SYS_MKNS, schemes.as_ptr() as usize, schemes.len()) }
 }
 
-/// Sleep for the time specified in `req`
+/// Sleeps for the time specified in `req`.
 pub fn nanosleep(req: &TimeSpec, rem: &mut TimeSpec) -> Result<usize> {
     unsafe { syscall2(SYS_NANOSLEEP, req as *const TimeSpec as usize,
                                      rem as *mut TimeSpec as usize) }
 }
 
-/// Open a file
+/// Opens a file.
 pub fn open<T: AsRef<[u8]>>(path: T, flags: usize) -> Result<usize> {
     unsafe { syscall3(SYS_OPEN, path.as_ref().as_ptr() as usize, path.as_ref().len(), flags) }
 }
 
-/// Allocate pages, linearly in physical memory
+/// Allocates pages, linearly in physical memory.
 pub unsafe fn physalloc(size: usize) -> Result<usize> {
     syscall1(SYS_PHYSALLOC, size)
 }
 
-/// Free physically allocated pages
+/// Frees physically allocated pages.
 pub unsafe fn physfree(physical_address: usize, size: usize) -> Result<usize> {
     syscall2(SYS_PHYSFREE, physical_address, size)
 }
 
-/// Map physical memory to virtual memory
+/// Maps physical memory to virtual memory.
 pub unsafe fn physmap(physical_address: usize, size: usize, flags: usize) -> Result<usize> {
     syscall3(SYS_PHYSMAP, physical_address, size, flags)
 }
 
-/// Unmap previously mapped physical memory
+/// Unmaps previously mapped physical memory.
 pub unsafe fn physunmap(virtual_address: usize) -> Result<usize> {
     syscall1(SYS_PHYSUNMAP, virtual_address)
 }
 
-/// Create a pair of file descriptors referencing the read and write ends of a pipe
+/// Creates a pair of file descriptors referencing the read and write ends of a pipe.
 pub fn pipe2(fds: &mut [usize; 2], flags: usize) -> Result<usize> {
     unsafe { syscall2(SYS_PIPE2, fds.as_ptr() as usize, flags) }
 }
@@ -268,32 +268,32 @@ pub fn read(fd: usize, buf: &mut [u8]) -> Result<usize> {
     unsafe { syscall3(SYS_READ, fd, buf.as_mut_ptr() as usize, buf.len()) }
 }
 
-/// Remove a directory
+/// Removes a directory.
 pub fn rmdir<T: AsRef<[u8]>>(path: T) -> Result<usize> {
     unsafe { syscall2(SYS_RMDIR, path.as_ref().as_ptr() as usize, path.as_ref().len()) }
 }
 
-/// Set the process group ID
+/// Sets the process group ID.
 pub fn setpgid(pid: usize, pgid: usize) -> Result<usize> {
     unsafe { syscall2(SYS_SETPGID, pid, pgid) }
 }
 
-/// Set the current process group IDs
+/// Sets the current process group IDs.
 pub fn setregid(rgid: usize, egid: usize) -> Result<usize> {
     unsafe { syscall2(SYS_SETREGID, rgid, egid) }
 }
 
-/// Make a new scheme namespace
+/// Makes a new scheme namespace.
 pub fn setrens(rns: usize, ens: usize) -> Result<usize> {
     unsafe { syscall2(SYS_SETRENS, rns, ens) }
 }
 
-/// Set the current process user IDs
+/// Sets the current process user IDs.
 pub fn setreuid(ruid: usize, euid: usize) -> Result<usize> {
     unsafe { syscall2(SYS_SETREUID, ruid, euid) }
 }
 
-/// Set up a signal handler
+/// Sets up a signal handler.
 pub fn sigaction(sig: usize, act: Option<&SigAction>, oldact: Option<&mut SigAction>)
 -> Result<usize> {
     unsafe { syscall4(SYS_SIGACTION, sig,
@@ -302,27 +302,27 @@ pub fn sigaction(sig: usize, act: Option<&SigAction>, oldact: Option<&mut SigAct
                       restorer as usize) }
 }
 
-// Return from signal handler
+/// Returns from signal handler.
 pub fn sigreturn() -> Result<usize> {
     unsafe { syscall0(SYS_SIGRETURN) }
 }
 
-/// Remove a file
+/// Removes a file.
 pub fn unlink<T: AsRef<[u8]>>(path: T) -> Result<usize> {
     unsafe { syscall2(SYS_UNLINK, path.as_ref().as_ptr() as usize, path.as_ref().len()) }
 }
 
-/// Convert a virtual address to a physical one
+/// Converts a virtual address to a physical one.
 pub unsafe fn virttophys(virtual_address: usize) -> Result<usize> {
     syscall1(SYS_VIRTTOPHYS, virtual_address)
 }
 
-/// Check if a child process has exited or received a signal
+/// Checks if a child process has exited or received a signal.
 pub fn waitpid(pid: usize, status: &mut usize, options: usize) -> Result<usize> {
     unsafe { syscall3(SYS_WAITPID, pid, status as *mut usize as usize, options) }
 }
 
-/// Write a buffer to a file descriptor
+/// Writes a buffer to a file descriptor.
 ///
 /// The kernel will attempt to write the bytes in `buf` to the file descriptor `fd`, returning
 /// either an `Err`, explained below, or `Ok(count)` where `count` is the number of bytes which
@@ -340,7 +340,7 @@ pub fn write(fd: usize, buf: &[u8]) -> Result<usize> {
     unsafe { syscall3(SYS_WRITE, fd, buf.as_ptr() as usize, buf.len()) }
 }
 
-/// Yield the process's time slice to the kernel
+/// Yields the process's time slice to the kernel.
 ///
 /// This function will return Ok(0) on success
 pub fn sched_yield() -> Result<usize> {
diff --git a/src/libstd/sys/redox/syscall/flag.rs b/src/libstd/sys/redox/syscall/flag.rs
index a41bc6d4a8b54..5820f1ad03a31 100644
--- a/src/libstd/sys/redox/syscall/flag.rs
+++ b/src/libstd/sys/redox/syscall/flag.rs
@@ -107,42 +107,42 @@ pub const WNOHANG: usize =    0x01;
 pub const WUNTRACED: usize =  0x02;
 pub const WCONTINUED: usize = 0x08;
 
-/// True if status indicates the child is stopped.
+/// Returns `true` if status indicates the child is stopped.
 pub fn wifstopped(status: usize) -> bool {
     (status & 0xff) == 0x7f
 }
 
-/// If wifstopped(status), the signal that stopped the child.
+/// If wifstopped(status), returns the signal that stopped the child.
 pub fn wstopsig(status: usize) -> usize {
     (status >> 8) & 0xff
 }
 
-/// True if status indicates the child continued after a stop.
+/// Returns `true` if status indicates the child continued after a stop.
 pub fn wifcontinued(status: usize) -> bool {
     status == 0xffff
 }
 
-/// True if STATUS indicates termination by a signal.
+/// Returns `true` if status indicates termination by a signal.
 pub fn wifsignaled(status: usize) -> bool {
     ((status & 0x7f) + 1) as i8 >= 2
 }
 
-/// If wifsignaled(status), the terminating signal.
+/// If wifsignaled(status), returns the terminating signal.
 pub fn wtermsig(status: usize) -> usize {
     status & 0x7f
 }
 
-/// True if status indicates normal termination.
+/// Returns `true` if status indicates normal termination.
 pub fn wifexited(status: usize) -> bool {
     wtermsig(status) == 0
 }
 
-/// If wifexited(status), the exit status.
+/// If wifexited(status), returns the exit status.
 pub fn wexitstatus(status: usize) -> usize {
     (status >> 8) & 0xff
 }
 
-/// True if status indicates a core dump was created.
+/// Returns `true` if status indicates a core dump was created.
 pub fn wcoredump(status: usize) -> bool {
     (status & 0x80) != 0
 }
diff --git a/src/libstd/sys/redox/thread_local.rs b/src/libstd/sys/redox/thread_local.rs
index a1c4b10e45063..a1929b941659d 100644
--- a/src/libstd/sys/redox/thread_local.rs
+++ b/src/libstd/sys/redox/thread_local.rs
@@ -2,13 +2,13 @@
 
 use collections::BTreeMap;
 use ptr;
-use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use sync::atomic::{AtomicUsize, Ordering};
 
 pub type Key = usize;
 
 type Dtor = unsafe extern fn(*mut u8);
 
-static NEXT_KEY: AtomicUsize = ATOMIC_USIZE_INIT;
+static NEXT_KEY: AtomicUsize = AtomicUsize::new(0);
 
 static mut KEYS: *mut BTreeMap<Key, Option<Dtor>> = ptr::null_mut();
 
diff --git a/src/libstd/sys/sgx/abi/entry.S b/src/libstd/sys/sgx/abi/entry.S
index ac7f95d4eae80..c03e3869aa3c8 100644
--- a/src/libstd/sys/sgx/abi/entry.S
+++ b/src/libstd/sys/sgx/abi/entry.S
@@ -66,13 +66,9 @@ IMAGE_BASE:
     globvar EH_FRM_HDR_SIZE 8
 
 .Lreentry_panic_msg:
-    .asciz "Re-entered panicked enclave!"
+    .asciz "Re-entered aborted enclave!"
 .Lreentry_panic_msg_end:
 
-.Lusercall_panic_msg:
-    .asciz "Invalid usercall#!"
-.Lusercall_panic_msg_end:
-
 .org .Lxsave_clear+512
 .Lxsave_header:
     .int 0, 0 /*  XSTATE_BV */
@@ -80,7 +76,7 @@ IMAGE_BASE:
     .org .+48 /*  reserved bits */
 
 .data
-.Lpanicked:
+.Laborted:
     .byte 0
 
 /*  TCS local storage section */
@@ -134,6 +130,9 @@ sgx_entry:
     jz .Lskip_debug_init
     mov %r10,%gs:tcsls_debug_panic_buf_ptr
 .Lskip_debug_init:
+/*  check for abort */
+    bt $0,.Laborted(%rip)
+    jc .Lreentry_panic
 /*  check if returning from usercall */
     mov %gs:tcsls_last_rsp,%r11
     test %r11,%r11
@@ -164,9 +163,6 @@ sgx_entry:
     mov %r14,%r8
     mov %r15,%r9
 .Lskip_init:
-/*  check for panic */
-    bt $0,.Lpanicked(%rip)
-    jc .Lreentry_panic
 /*  call into main entry point */
     load_tcsls_flag_secondary_bool cx /* RCX = entry() argument: secondary: bool */
     call entry /* RDI, RSI, RDX, R8, R9 passed in from userspace */
@@ -219,13 +215,21 @@ sgx_entry:
     orq $8,%rsp
     jmp panic_msg
 
-.Lusercall_panic:
-    lea .Lusercall_panic_msg(%rip),%rdi
-    mov $.Lusercall_panic_msg_end-.Lusercall_panic_msg,%esi
-    orq $8,%rsp
-    jmp panic_msg
-
-.macro push_callee_saved_registers
+/*  This *MUST* be called with 6 parameters, otherwise register information */
+/*  might leak! */
+.global usercall
+usercall:
+    test %rcx,%rcx            /* check `abort` function argument */
+    jnz .Lusercall_abort      /* abort is set, jump to abort code (unlikely forward conditional) */
+    jmp .Lusercall_save_state /* non-aborting usercall */
+.Lusercall_abort:
+/* set aborted bit */
+    movb $1,.Laborted(%rip)
+/* save registers in DEBUG mode, so that debugger can reconstruct the stack */
+    testb $0xff,DEBUG(%rip)
+    jz .Lusercall_noreturn
+.Lusercall_save_state:
+/*  save callee-saved state */
     push %r15
     push %r14
     push %r13
@@ -235,33 +239,8 @@ sgx_entry:
     sub $8, %rsp
     fstcw 4(%rsp)
     stmxcsr (%rsp)
-.endm
-
-.global panic_exit
-panic_exit:
-/* save registers in DEBUG mode, so that debugger can reconstruct the stack */
-    testb $0xff,DEBUG(%rip)
-    jz .Lskip_save_registers
-    push_callee_saved_registers
-    movq %rsp,%gs:tcsls_panic_last_rsp
-.Lskip_save_registers:
-/* set panicked bit */
-    movb $1,.Lpanicked(%rip)
-/* call usercall exit(true) */
-    mov $1,%esi   /*  RSI = usercall() argument: panic = true */
-    xor %rdx,%rdx /*  RDX cleared */
-    movq $usercall_nr_exit,%rdi /*  RDI = usercall exit */
-    jmp .Lexit
-
-/*  This *MUST* be called with 6 parameters, otherwise register information */
-/*  might leak! */
-.global usercall
-usercall:
-    test %rdi,%rdi
-    jle .Lusercall_panic
-/*  save callee-saved state */
-    push_callee_saved_registers
     movq %rsp,%gs:tcsls_last_rsp
+.Lusercall_noreturn:
 /*  clear general purpose register state */
     /*  RAX overwritten by ENCLU */
     /*  RBX set by sgx_exit */
@@ -281,7 +260,7 @@ usercall:
     jmp .Lsgx_exit
 .Lusercall_ret:
     movq $0,%gs:tcsls_last_rsp
-/*  restore callee-saved state, cf. push_callee_saved_registers */
+/*  restore callee-saved state, cf. "save" above */
     mov %r11,%rsp
     ldmxcsr (%rsp)
     fldcw 4(%rsp)
diff --git a/src/libstd/sys/sgx/abi/mod.rs b/src/libstd/sys/sgx/abi/mod.rs
index 5ef069aa81c66..509a1990d978b 100644
--- a/src/libstd/sys/sgx/abi/mod.rs
+++ b/src/libstd/sys/sgx/abi/mod.rs
@@ -12,7 +12,7 @@ pub mod tls;
 #[macro_use]
 pub mod usercalls;
 
-global_asm!(concat!(usercalls_asm!(), include_str!("entry.S")));
+global_asm!(include_str!("entry.S"));
 
 #[no_mangle]
 unsafe extern "C" fn tcs_init(secondary: bool) {
diff --git a/src/libstd/sys/sgx/abi/panic.rs b/src/libstd/sys/sgx/abi/panic.rs
index 5ace7fb3368b6..b2afacc70b82e 100644
--- a/src/libstd/sys/sgx/abi/panic.rs
+++ b/src/libstd/sys/sgx/abi/panic.rs
@@ -1,12 +1,18 @@
+use super::usercalls::{alloc::UserRef, self};
+use cmp;
 use io::{self, Write};
-use slice::from_raw_parts_mut;
+use mem;
 
 extern "C" {
     fn take_debug_panic_buf_ptr() -> *mut u8;
     static DEBUG: u8;
 }
 
-pub(crate) struct SgxPanicOutput(Option<&'static mut [u8]>);
+pub(crate) struct SgxPanicOutput(Option<&'static mut UserRef<[u8]>>);
+
+fn empty_user_slice() -> &'static mut UserRef<[u8]> {
+    unsafe { UserRef::from_raw_parts_mut(1 as *mut u8, 0) }
+}
 
 impl SgxPanicOutput {
     pub(crate) fn new() -> Option<Self> {
@@ -17,32 +23,34 @@ impl SgxPanicOutput {
         }
     }
 
-    fn init(&mut self) -> &mut &'static mut [u8] {
+    fn init(&mut self) -> &mut &'static mut UserRef<[u8]> {
         self.0.get_or_insert_with(|| unsafe {
             let ptr = take_debug_panic_buf_ptr();
             if ptr.is_null() {
-                &mut []
+                empty_user_slice()
             } else {
-                from_raw_parts_mut(ptr, 1024)
+                UserRef::from_raw_parts_mut(ptr, 1024)
             }
         })
     }
 }
 
 impl Write for SgxPanicOutput {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        self.init().write(buf)
+    fn write(&mut self, src: &[u8]) -> io::Result<usize> {
+        let dst = mem::replace(self.init(), empty_user_slice());
+        let written = cmp::min(src.len(), dst.len());
+        dst[..written].copy_from_enclave(&src[..written]);
+        self.0 = Some(&mut dst[written..]);
+        Ok(written)
     }
 
     fn flush(&mut self) -> io::Result<()> {
-        self.init().flush()
+        Ok(())
     }
 }
 
 #[no_mangle]
 pub extern "C" fn panic_msg(msg: &str) -> ! {
     let _ = SgxPanicOutput::new().map(|mut out| out.write(msg.as_bytes()));
-    unsafe { panic_exit(); }
+    usercalls::exit(true)
 }
-
-extern "C" { pub fn panic_exit() -> !; }
diff --git a/src/libstd/sys/sgx/abi/thread.rs b/src/libstd/sys/sgx/abi/thread.rs
index 588fbcd9d4304..86fe09d003520 100644
--- a/src/libstd/sys/sgx/abi/thread.rs
+++ b/src/libstd/sys/sgx/abi/thread.rs
@@ -1,6 +1,6 @@
 use fortanix_sgx_abi::Tcs;
 
-/// Get the ID for the current thread. The ID is guaranteed to be unique among
+/// Gets the ID for the current thread. The ID is guaranteed to be unique among
 /// all currently running threads in the enclave, and it is guaranteed to be
 /// constant for the lifetime of the thread. More specifically for SGX, there
 /// is a one-to-one correspondence of the ID to the address of the TCS.
diff --git a/src/libstd/sys/sgx/abi/tls.rs b/src/libstd/sys/sgx/abi/tls.rs
index aba93db915fe8..e1fc369684527 100644
--- a/src/libstd/sys/sgx/abi/tls.rs
+++ b/src/libstd/sys/sgx/abi/tls.rs
@@ -1,4 +1,4 @@
-use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use sync::atomic::{AtomicUsize, Ordering};
 use ptr;
 use mem;
 use cell::Cell;
@@ -15,7 +15,40 @@ macro_rules! dup {
     ((* $($exp:tt)*) $($val:tt)*) => (dup!( ($($exp)*) $($val)* $($val)* ));
     (() $($val:tt)*) => ([$($val),*])
 }
-static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = dup!((* * * * * * *) ATOMIC_USIZE_INIT);
+static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = [
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+    AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0), AtomicUsize::new(0),
+];
 
 extern "C" {
     fn get_tls_ptr() -> *const u8;
@@ -119,7 +152,7 @@ impl Tls {
 }
 
 mod sync_bitset {
-    use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+    use sync::atomic::{AtomicUsize, Ordering};
     use iter::{Enumerate, Peekable};
     use slice::Iter;
     use super::{TLS_KEYS_BITSET_SIZE, USIZE_BITS};
@@ -128,7 +161,7 @@ mod sync_bitset {
     pub(super) struct SyncBitset([AtomicUsize; TLS_KEYS_BITSET_SIZE]);
 
     pub(super) const SYNC_BITSET_INIT: SyncBitset =
-        SyncBitset([ATOMIC_USIZE_INIT, ATOMIC_USIZE_INIT]);
+        SyncBitset([AtomicUsize::new(0), AtomicUsize::new(0)]);
 
     impl SyncBitset {
         pub fn get(&self, index: usize) -> bool {
@@ -149,7 +182,7 @@ mod sync_bitset {
             self.0[hi].fetch_and(!lo, Ordering::Relaxed);
         }
 
-        /// Set any unset bit. Not atomic. Returns `None` if all bits were
+        /// Sets any unset bit. Not atomic. Returns `None` if all bits were
         /// observed to be set.
         pub fn set(&self) -> Option<usize> {
             'elems: for (idx, elem) in self.0.iter().enumerate() {
diff --git a/src/libstd/sys/sgx/abi/usercalls/alloc.rs b/src/libstd/sys/sgx/abi/usercalls/alloc.rs
index 8d0013a235ac7..0ccbbbc65015d 100644
--- a/src/libstd/sys/sgx/abi/usercalls/alloc.rs
+++ b/src/libstd/sys/sgx/abi/usercalls/alloc.rs
@@ -63,44 +63,49 @@ pub unsafe trait UserSafe {
 
     /// Construct a pointer to `Self` given a memory range in user space.
     ///
-    /// NB. This takes a size, not a length!
+    /// N.B., this takes a size, not a length!
     ///
     /// # Safety
+    ///
     /// The caller must ensure the memory range is in user memory, is the
     /// correct size and is correctly aligned and points to the right type.
     unsafe fn from_raw_sized_unchecked(ptr: *mut u8, size: usize) -> *mut Self;
 
     /// Construct a pointer to `Self` given a memory range.
     ///
-    /// NB. This takes a size, not a length!
+    /// N.B., this takes a size, not a length!
     ///
     /// # Safety
+    ///
     /// The caller must ensure the memory range points to the correct type.
     ///
     /// # Panics
+    ///
     /// This function panics if:
     ///
-    /// * The pointer is not aligned
-    /// * The pointer is null
-    /// * The pointed-to range is not in user memory
+    /// * the pointer is not aligned.
+    /// * the pointer is null.
+    /// * the pointed-to range is not in user memory.
     unsafe fn from_raw_sized(ptr: *mut u8, size: usize) -> NonNull<Self> {
         let ret = Self::from_raw_sized_unchecked(ptr, size);
         Self::check_ptr(ret);
         NonNull::new_unchecked(ret as _)
     }
 
-    /// Check if a pointer may point to Self in user memory.
+    /// Checks if a pointer may point to `Self` in user memory.
     ///
     /// # Safety
+    ///
     /// The caller must ensure the memory range points to the correct type and
     /// length (if this is a slice).
     ///
     /// # Panics
+    ///
     /// This function panics if:
     ///
-    /// * The pointer is not aligned
-    /// * The pointer is null
-    /// * The pointed-to range is not in user memory
+    /// * the pointer is not aligned.
+    /// * the pointer is null.
+    /// * the pointed-to range is not in user memory.
     unsafe fn check_ptr(ptr: *const Self) {
         let is_aligned = |p| -> bool {
             0 == (p as usize) & (Self::align_of() - 1)
@@ -188,7 +193,7 @@ impl<T: ?Sized> User<T> where T: UserSafe {
         }
     }
 
-    /// Copy `val` into freshly allocated space in user memory.
+    /// Copies `val` into freshly allocated space in user memory.
     pub fn new_from_enclave(val: &T) -> Self {
         unsafe {
             let ret = Self::new_uninit_bytes(mem::size_of_val(val));
@@ -201,7 +206,7 @@ impl<T: ?Sized> User<T> where T: UserSafe {
         }
     }
 
-    /// Create an owned `User<T>` from a raw pointer.
+    /// Creates an owned `User<T>` from a raw pointer.
     ///
     /// # Safety
     /// The caller must ensure `ptr` points to `T`, is freeable with the `free`
@@ -218,7 +223,7 @@ impl<T: ?Sized> User<T> where T: UserSafe {
         User(NonNull::new_userref(ptr))
     }
 
-    /// Convert this value into a raw pointer. The value will no longer be
+    /// Converts this value into a raw pointer. The value will no longer be
     /// automatically freed.
     pub fn into_raw(self) -> *mut T {
         let ret = self.0;
@@ -242,7 +247,7 @@ impl<T> User<[T]> where [T]: UserSafe {
         Self::new_uninit_bytes(n * mem::size_of::<T>())
     }
 
-    /// Create an owned `User<[T]>` from a raw thin pointer and a slice length.
+    /// Creates an owned `User<[T]>` from a raw thin pointer and a slice length.
     ///
     /// # Safety
     /// The caller must ensure `ptr` points to `len` elements of `T`, is
@@ -262,7 +267,7 @@ impl<T> User<[T]> where [T]: UserSafe {
 
 #[unstable(feature = "sgx_platform", issue = "56975")]
 impl<T: ?Sized> UserRef<T> where T: UserSafe {
-    /// Create a `&UserRef<[T]>` from a raw pointer.
+    /// Creates a `&UserRef<[T]>` from a raw pointer.
     ///
     /// # Safety
     /// The caller must ensure `ptr` points to `T`.
@@ -278,7 +283,7 @@ impl<T: ?Sized> UserRef<T> where T: UserSafe {
         &*(ptr as *const Self)
     }
 
-    /// Create a `&mut UserRef<[T]>` from a raw pointer. See the struct
+    /// Creates a `&mut UserRef<[T]>` from a raw pointer. See the struct
     /// documentation for the nuances regarding a `&mut UserRef<T>`.
     ///
     /// # Safety
@@ -295,7 +300,7 @@ impl<T: ?Sized> UserRef<T> where T: UserSafe {
         &mut*(ptr as *mut Self)
     }
 
-    /// Copy `val` into user memory.
+    /// Copies `val` into user memory.
     ///
     /// # Panics
     /// This function panics if the destination doesn't have the same size as
@@ -311,7 +316,7 @@ impl<T: ?Sized> UserRef<T> where T: UserSafe {
         }
     }
 
-    /// Copy the value from user memory and place it into `dest`.
+    /// Copies the value from user memory and place it into `dest`.
     ///
     /// # Panics
     /// This function panics if the destination doesn't have the same size as
@@ -340,7 +345,7 @@ impl<T: ?Sized> UserRef<T> where T: UserSafe {
 
 #[unstable(feature = "sgx_platform", issue = "56975")]
 impl<T> UserRef<T> where T: UserSafe {
-    /// Copy the value from user memory into enclave memory.
+    /// Copies the value from user memory into enclave memory.
     pub fn to_enclave(&self) -> T {
         unsafe { ptr::read(self.0.get()) }
     }
@@ -348,7 +353,7 @@ impl<T> UserRef<T> where T: UserSafe {
 
 #[unstable(feature = "sgx_platform", issue = "56975")]
 impl<T> UserRef<[T]> where [T]: UserSafe {
-    /// Create a `&UserRef<[T]>` from a raw thin pointer and a slice length.
+    /// Creates a `&UserRef<[T]>` from a raw thin pointer and a slice length.
     ///
     /// # Safety
     /// The caller must ensure `ptr` points to `n` elements of `T`.
@@ -363,7 +368,7 @@ impl<T> UserRef<[T]> where [T]: UserSafe {
         &*(<[T]>::from_raw_sized(ptr as _, len * mem::size_of::<T>()).as_ptr() as *const Self)
     }
 
-    /// Create a `&mut UserRef<[T]>` from a raw thin pointer and a slice length.
+    /// Creates a `&mut UserRef<[T]>` from a raw thin pointer and a slice length.
     /// See the struct documentation for the nuances regarding a
     /// `&mut UserRef<T>`.
     ///
@@ -395,7 +400,7 @@ impl<T> UserRef<[T]> where [T]: UserSafe {
         unsafe { (*self.0.get()).len() }
     }
 
-    /// Copy the value from user memory and place it into `dest`. Afterwards,
+    /// Copies the value from user memory and place it into `dest`. Afterwards,
     /// `dest` will contain exactly `self.len()` elements.
     ///
     /// # Panics
@@ -411,7 +416,7 @@ impl<T> UserRef<[T]> where [T]: UserSafe {
         }
     }
 
-    /// Copy the value from user memory into a vector in enclave memory.
+    /// Copies the value from user memory into a vector in enclave memory.
     pub fn to_enclave(&self) -> Vec<T> {
         let mut ret = Vec::with_capacity(self.len());
         self.copy_to_enclave_vec(&mut ret);
@@ -526,7 +531,7 @@ impl<T, I: SliceIndex<[T]>> IndexMut<I> for UserRef<[T]> where [T]: UserSafe, I:
 
 #[unstable(feature = "sgx_platform", issue = "56975")]
 impl UserRef<super::raw::ByteBuffer> {
-    /// Copy the user memory range pointed to by the user `ByteBuffer` to
+    /// Copies the user memory range pointed to by the user `ByteBuffer` to
     /// enclave memory.
     ///
     /// # Panics
@@ -537,7 +542,12 @@ impl UserRef<super::raw::ByteBuffer> {
     pub fn copy_user_buffer(&self) -> Vec<u8> {
         unsafe {
             let buf = self.to_enclave();
-            User::from_raw_parts(buf.data as _, buf.len).to_enclave()
+            if buf.len > 0 {
+                User::from_raw_parts(buf.data as _, buf.len).to_enclave()
+            } else {
+                // Mustn't look at `data` or call `free` if `len` is `0`.
+                Vec::with_capacity(0)
+            }
         }
     }
 }
diff --git a/src/libstd/sys/sgx/abi/usercalls/mod.rs b/src/libstd/sys/sgx/abi/usercalls/mod.rs
index 58903761ebe40..511d6e9e9273a 100644
--- a/src/libstd/sys/sgx/abi/usercalls/mod.rs
+++ b/src/libstd/sys/sgx/abi/usercalls/mod.rs
@@ -22,7 +22,8 @@ pub fn read(fd: Fd, buf: &mut [u8]) -> IoResult<usize> {
 #[unstable(feature = "sgx_platform", issue = "56975")]
 pub fn read_alloc(fd: Fd) -> IoResult<Vec<u8>> {
     unsafe {
-        let mut userbuf = alloc::User::<ByteBuffer>::uninitialized();
+        let userbuf = ByteBuffer { data: ::ptr::null_mut(), len: 0 };
+        let mut userbuf = alloc::User::new_from_enclave(&userbuf);
         raw::read_alloc(fd, userbuf.as_raw_mut_ptr()).from_sgx_result()?;
         Ok(userbuf.copy_user_buffer())
     }
diff --git a/src/libstd/sys/sgx/abi/usercalls/raw.rs b/src/libstd/sys/sgx/abi/usercalls/raw.rs
index 27aca7c0903de..447f20584f859 100644
--- a/src/libstd/sys/sgx/abi/usercalls/raw.rs
+++ b/src/libstd/sys/sgx/abi/usercalls/raw.rs
@@ -4,26 +4,31 @@
 pub use fortanix_sgx_abi::*;
 
 use ptr::NonNull;
+use num::NonZeroU64;
 
 #[repr(C)]
 struct UsercallReturn(u64, u64);
 
 extern "C" {
-    fn usercall(nr: u64, p1: u64, p2: u64, _ignore: u64, p3: u64, p4: u64) -> UsercallReturn;
+    fn usercall(nr: NonZeroU64, p1: u64, p2: u64, abort: u64, p3: u64, p4: u64) -> UsercallReturn;
 }
 
-/// Perform the raw usercall operation as defined in the ABI calling convention.
+/// Performs the raw usercall operation as defined in the ABI calling convention.
 ///
 /// # Safety
+///
 /// The caller must ensure to pass parameters appropriate for the usercall `nr`
 /// and to observe all requirements specified in the ABI.
 ///
 /// # Panics
-/// Panics if `nr` is 0.
+///
+/// Panics if `nr` is `0`.
 #[unstable(feature = "sgx_platform", issue = "56975")]
-pub unsafe fn do_usercall(nr: u64, p1: u64, p2: u64, p3: u64, p4: u64) -> (u64, u64) {
-    if nr==0 { panic!("Invalid usercall number {}",nr) }
-    let UsercallReturn(a, b) = usercall(nr,p1,p2,0,p3,p4);
+#[inline]
+pub unsafe fn do_usercall(nr: NonZeroU64, p1: u64, p2: u64, p3: u64, p4: u64, abort: bool)
+    -> (u64, u64)
+{
+    let UsercallReturn(a, b) = usercall(nr, p1, p2, abort as _, p3, p4);
     (a, b)
 }
 
@@ -39,12 +44,16 @@ trait ReturnValue {
 }
 
 macro_rules! define_usercalls {
-    // Using `$r:tt` because `$r:ty` doesn't match ! in `clobber_diverging`
     ($(fn $f:ident($($n:ident: $t:ty),*) $(-> $r:tt)*; )*) => {
-        #[repr(C)]
-        #[allow(non_camel_case_types)]
-        enum Usercalls {
-            __enclave_usercalls_invalid,
+        /// Usercall numbers as per the ABI.
+        #[repr(u64)]
+        #[unstable(feature = "sgx_platform", issue = "56975")]
+        #[derive(Copy, Clone, Hash, PartialEq, Eq, Debug)]
+        #[allow(missing_docs, non_camel_case_types)]
+        #[non_exhaustive]
+        pub enum Usercalls {
+            #[doc(hidden)]
+            __enclave_usercalls_invalid = 0,
             $($f,)*
         }
 
@@ -52,22 +61,6 @@ macro_rules! define_usercalls {
     };
 }
 
-macro_rules! define_usercalls_asm {
-    ($(fn $f:ident($($n:ident: $t:ty),*) $(-> $r:ty)*; )*) => {
-        macro_rules! usercalls_asm {
-            () => {
-                concat!(
-                    ".equ usercall_nr_LAST, 0\n",
-                    $(
-                    ".equ usercall_nr_", stringify!($f), ", usercall_nr_LAST+1\n",
-                    ".equ usercall_nr_LAST, usercall_nr_", stringify!($f), "\n"
-                    ),*
-                )
-            }
-        }
-    };
-}
-
 macro_rules! define_ra {
     (< $i:ident > $t:ty) => {
         impl<$i> RegisterArgument for $t {
@@ -166,74 +159,90 @@ impl<T: RegisterArgument, U: RegisterArgument> ReturnValue for (T, U) {
     }
 }
 
+macro_rules! return_type_is_abort {
+    (!) => { true };
+    ($r:ty) => { false };
+}
+
+// In this macro: using `$r:tt` because `$r:ty` doesn't match ! in `return_type_is_abort`
 macro_rules! enclave_usercalls_internal_define_usercalls {
     (def fn $f:ident($n1:ident: $t1:ty, $n2:ident: $t2:ty,
-                     $n3:ident: $t3:ty, $n4:ident: $t4:ty) -> $r:ty) => (
+                     $n3:ident: $t3:ty, $n4:ident: $t4:ty) -> $r:tt) => (
         /// This is the raw function definition, see the ABI documentation for
         /// more information.
         #[unstable(feature = "sgx_platform", issue = "56975")]
         #[inline(always)]
         pub unsafe fn $f($n1: $t1, $n2: $t2, $n3: $t3, $n4: $t4) -> $r {
             ReturnValue::from_registers(stringify!($f), do_usercall(
-                Usercalls::$f as Register,
+                NonZeroU64::new(Usercalls::$f as Register)
+                    .expect("Usercall number must be non-zero"),
                 RegisterArgument::into_register($n1),
                 RegisterArgument::into_register($n2),
                 RegisterArgument::into_register($n3),
                 RegisterArgument::into_register($n4),
+                return_type_is_abort!($r)
             ))
         }
     );
-    (def fn $f:ident($n1:ident: $t1:ty, $n2:ident: $t2:ty, $n3:ident: $t3:ty) -> $r:ty) => (
+    (def fn $f:ident($n1:ident: $t1:ty, $n2:ident: $t2:ty, $n3:ident: $t3:ty) -> $r:tt) => (
         /// This is the raw function definition, see the ABI documentation for
         /// more information.
         #[unstable(feature = "sgx_platform", issue = "56975")]
         #[inline(always)]
         pub unsafe fn $f($n1: $t1, $n2: $t2, $n3: $t3) -> $r {
             ReturnValue::from_registers(stringify!($f), do_usercall(
-                Usercalls::$f as Register,
+                NonZeroU64::new(Usercalls::$f as Register)
+                    .expect("Usercall number must be non-zero"),
                 RegisterArgument::into_register($n1),
                 RegisterArgument::into_register($n2),
                 RegisterArgument::into_register($n3),
-                0
+                0,
+                return_type_is_abort!($r)
             ))
         }
     );
-    (def fn $f:ident($n1:ident: $t1:ty, $n2:ident: $t2:ty) -> $r:ty) => (
+    (def fn $f:ident($n1:ident: $t1:ty, $n2:ident: $t2:ty) -> $r:tt) => (
         /// This is the raw function definition, see the ABI documentation for
         /// more information.
         #[unstable(feature = "sgx_platform", issue = "56975")]
         #[inline(always)]
         pub unsafe fn $f($n1: $t1, $n2: $t2) -> $r {
             ReturnValue::from_registers(stringify!($f), do_usercall(
-                Usercalls::$f as Register,
+                NonZeroU64::new(Usercalls::$f as Register)
+                    .expect("Usercall number must be non-zero"),
                 RegisterArgument::into_register($n1),
                 RegisterArgument::into_register($n2),
-                0,0
+                0,0,
+                return_type_is_abort!($r)
             ))
         }
     );
-    (def fn $f:ident($n1:ident: $t1:ty) -> $r:ty) => (
+    (def fn $f:ident($n1:ident: $t1:ty) -> $r:tt) => (
         /// This is the raw function definition, see the ABI documentation for
         /// more information.
         #[unstable(feature = "sgx_platform", issue = "56975")]
         #[inline(always)]
         pub unsafe fn $f($n1: $t1) -> $r {
             ReturnValue::from_registers(stringify!($f), do_usercall(
-                Usercalls::$f as Register,
+                NonZeroU64::new(Usercalls::$f as Register)
+                    .expect("Usercall number must be non-zero"),
                 RegisterArgument::into_register($n1),
-                0,0,0
+                0,0,0,
+                return_type_is_abort!($r)
             ))
         }
     );
-    (def fn $f:ident() -> $r:ty) => (
+    (def fn $f:ident() -> $r:tt) => (
         /// This is the raw function definition, see the ABI documentation for
         /// more information.
         #[unstable(feature = "sgx_platform", issue = "56975")]
         #[inline(always)]
         pub unsafe fn $f() -> $r {
             ReturnValue::from_registers(stringify!($f), do_usercall(
-                Usercalls::$f as Register,
-                0,0,0,0
+                NonZeroU64::new(Usercalls::$f as Register)
+                    .expect("Usercall number must be non-zero"),
+                0,0,0,0,
+                return_type_is_abort!($r)
             ))
         }
     );
@@ -243,4 +252,3 @@ macro_rules! enclave_usercalls_internal_define_usercalls {
 }
 
 invoke_with_usercalls!(define_usercalls);
-invoke_with_usercalls!(define_usercalls_asm);
diff --git a/src/libstd/sys/sgx/ext/arch.rs b/src/libstd/sys/sgx/ext/arch.rs
index 3bd87b5d26574..97f7d9181a539 100644
--- a/src/libstd/sys/sgx/ext/arch.rs
+++ b/src/libstd/sys/sgx/ext/arch.rs
@@ -41,7 +41,7 @@ pub fn egetkey(request: &Align512<[u8; 512]>) -> Result<Align16<[u8; 16]>, u32>
         );
 
         match error {
-            0 => Ok(out.into_inner()),
+            0 => Ok(out.into_initialized()),
             err => Err(err),
         }
     }
@@ -69,6 +69,6 @@ pub fn ereport(
               "{rdx}"(report.as_mut_ptr())
         );
 
-        report.into_inner()
+        report.into_initialized()
     }
 }
diff --git a/src/libstd/sys/sgx/ext/ffi.rs b/src/libstd/sys/sgx/ext/ffi.rs
new file mode 100644
index 0000000000000..7b0ffea49ae7c
--- /dev/null
+++ b/src/libstd/sys/sgx/ext/ffi.rs
@@ -0,0 +1,109 @@
+//! SGX-specific extension to the primitives in the `std::ffi` module
+
+#![unstable(feature = "sgx_platform", issue = "56975")]
+
+use ffi::{OsStr, OsString};
+use mem;
+use sys::os_str::Buf;
+use sys_common::{FromInner, IntoInner, AsInner};
+
+/// SGX-specific extensions to [`OsString`].
+///
+/// [`OsString`]: ../../../../std/ffi/struct.OsString.html
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub trait OsStringExt {
+    /// Creates an [`OsString`] from a byte vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::OsString;
+    /// use std::os::unix::ffi::OsStringExt;
+    ///
+    /// let bytes = b"foo".to_vec();
+    /// let os_string = OsString::from_vec(bytes);
+    /// assert_eq!(os_string.to_str(), Some("foo"));
+    /// ```
+    ///
+    /// [`OsString`]: ../../../ffi/struct.OsString.html
+    #[unstable(feature = "sgx_platform", issue = "56975")]
+    fn from_vec(vec: Vec<u8>) -> Self;
+
+    /// Yields the underlying byte vector of this [`OsString`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::OsString;
+    /// use std::os::unix::ffi::OsStringExt;
+    ///
+    /// let mut os_string = OsString::new();
+    /// os_string.push("foo");
+    /// let bytes = os_string.into_vec();
+    /// assert_eq!(bytes, b"foo");
+    /// ```
+    ///
+    /// [`OsString`]: ../../../ffi/struct.OsString.html
+    #[unstable(feature = "sgx_platform", issue = "56975")]
+    fn into_vec(self) -> Vec<u8>;
+}
+
+#[unstable(feature = "sgx_platform", issue = "56975")]
+impl OsStringExt for OsString {
+    fn from_vec(vec: Vec<u8>) -> OsString {
+        FromInner::from_inner(Buf { inner: vec })
+    }
+    fn into_vec(self) -> Vec<u8> {
+        self.into_inner().inner
+    }
+}
+
+/// SGX-specific extensions to [`OsStr`].
+///
+/// [`OsStr`]: ../../../../std/ffi/struct.OsStr.html
+#[unstable(feature = "sgx_platform", issue = "56975")]
+pub trait OsStrExt {
+    #[unstable(feature = "sgx_platform", issue = "56975")]
+    /// Creates an [`OsStr`] from a byte slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::OsStr;
+    /// use std::os::unix::ffi::OsStrExt;
+    ///
+    /// let bytes = b"foo";
+    /// let os_str = OsStr::from_bytes(bytes);
+    /// assert_eq!(os_str.to_str(), Some("foo"));
+    /// ```
+    ///
+    /// [`OsStr`]: ../../../ffi/struct.OsStr.html
+    fn from_bytes(slice: &[u8]) -> &Self;
+
+    /// Gets the underlying byte view of the [`OsStr`] slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::OsStr;
+    /// use std::os::unix::ffi::OsStrExt;
+    ///
+    /// let mut os_str = OsStr::new("foo");
+    /// let bytes = os_str.as_bytes();
+    /// assert_eq!(bytes, b"foo");
+    /// ```
+    ///
+    /// [`OsStr`]: ../../../ffi/struct.OsStr.html
+    #[unstable(feature = "sgx_platform", issue = "56975")]
+    fn as_bytes(&self) -> &[u8];
+}
+
+#[unstable(feature = "sgx_platform", issue = "56975")]
+impl OsStrExt for OsStr {
+    fn from_bytes(slice: &[u8]) -> &OsStr {
+        unsafe { mem::transmute(slice) }
+    }
+    fn as_bytes(&self) -> &[u8] {
+        &self.as_inner().inner
+    }
+}
diff --git a/src/libstd/sys/sgx/ext/mod.rs b/src/libstd/sys/sgx/ext/mod.rs
index 5489f6f56946e..51b2659da83e3 100644
--- a/src/libstd/sys/sgx/ext/mod.rs
+++ b/src/libstd/sys/sgx/ext/mod.rs
@@ -2,3 +2,4 @@
 
 pub mod arch;
 pub mod io;
+pub mod ffi;
diff --git a/src/libstd/sys/sgx/mod.rs b/src/libstd/sys/sgx/mod.rs
index 7f8550490a199..4225ecbb20651 100644
--- a/src/libstd/sys/sgx/mod.rs
+++ b/src/libstd/sys/sgx/mod.rs
@@ -125,7 +125,7 @@ pub unsafe fn strlen(mut s: *const c_char) -> usize {
 }
 
 pub unsafe fn abort_internal() -> ! {
-    abi::panic::panic_exit()
+    abi::usercalls::exit(true)
 }
 
 pub fn hashmap_random_keys() -> (u64, u64) {
diff --git a/src/libstd/sys/sgx/rwlock.rs b/src/libstd/sys/sgx/rwlock.rs
index 47874158ed9df..33163a556c16d 100644
--- a/src/libstd/sys/sgx/rwlock.rs
+++ b/src/libstd/sys/sgx/rwlock.rs
@@ -1,3 +1,4 @@
+use alloc::{self, Layout};
 use num::NonZeroUsize;
 use slice;
 use str;
@@ -18,9 +19,6 @@ unsafe fn rw_lock_size_assert(r: RWLock) {
     mem::transmute::<RWLock, [u8; 128]>(r);
 }
 
-//unsafe impl Send for RWLock {}
-//unsafe impl Sync for RWLock {} // FIXME
-
 impl RWLock {
     pub const fn new() -> RWLock {
         RWLock {
@@ -147,6 +145,7 @@ impl RWLock {
         self.__write_unlock(rguard, wguard);
     }
 
+    // only used by __rust_rwlock_unlock below
     #[inline]
     unsafe fn unlock(&self) {
         let rguard = self.readers.lock();
@@ -164,6 +163,7 @@ impl RWLock {
 
 const EINVAL: i32 = 22;
 
+// used by libunwind port
 #[no_mangle]
 pub unsafe extern "C" fn __rust_rwlock_rdlock(p: *mut RWLock) -> i32 {
     if p.is_null() {
@@ -190,6 +190,8 @@ pub unsafe extern "C" fn __rust_rwlock_unlock(p: *mut RWLock) -> i32 {
     return 0;
 }
 
+// the following functions are also used by the libunwind port. They're
+// included here to make sure parallel codegen and LTO don't mess things up.
 #[no_mangle]
 pub unsafe extern "C" fn __rust_print_err(m: *mut u8, s: i32) {
     if s < 0 {
@@ -206,6 +208,16 @@ pub unsafe extern "C" fn __rust_abort() {
     ::sys::abort_internal();
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn __rust_c_alloc(size: usize, align: usize) -> *mut u8 {
+    alloc::alloc(Layout::from_size_align_unchecked(size, align))
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn __rust_c_dealloc(ptr: *mut u8, size: usize, align: usize) {
+    alloc::dealloc(ptr, Layout::from_size_align_unchecked(size, align))
+}
+
 #[cfg(test)]
 mod tests {
 
diff --git a/src/libstd/sys/sgx/waitqueue.rs b/src/libstd/sys/sgx/waitqueue.rs
index 51c00a1433e76..aec643b3175b4 100644
--- a/src/libstd/sys/sgx/waitqueue.rs
+++ b/src/libstd/sys/sgx/waitqueue.rs
@@ -3,7 +3,7 @@
 /// This queue is used to implement condition variable and mutexes.
 ///
 /// Users of this API are expected to use the `WaitVariable<T>` type. Since
-/// that type is not `Sync`, it needs to be protected by e.g. a `SpinMutex` to
+/// that type is not `Sync`, it needs to be protected by e.g., a `SpinMutex` to
 /// allow shared access.
 ///
 /// Since userspace may send spurious wake-ups, the wakeup event state is
@@ -136,7 +136,7 @@ impl WaitQueue {
         self.inner.is_empty()
     }
 
-    /// Add the calling thread to the WaitVariable's wait queue, then wait
+    /// Adds the calling thread to the `WaitVariable`'s wait queue, then wait
     /// until a wakeup event.
     ///
     /// This function does not return until this thread has been awoken.
diff --git a/src/libstd/sys/unix/ext/fs.rs b/src/libstd/sys/unix/ext/fs.rs
index e962d09e274e1..abcce3ab82962 100644
--- a/src/libstd/sys/unix/ext/fs.rs
+++ b/src/libstd/sys/unix/ext/fs.rs
@@ -684,7 +684,7 @@ impl MetadataExt for fs::Metadata {
 /// [`FileType`]: ../../../../std/fs/struct.FileType.html
 #[stable(feature = "file_type_ext", since = "1.5.0")]
 pub trait FileTypeExt {
-    /// Returns whether this file type is a block device.
+    /// Returns `true` if this file type is a block device.
     ///
     /// # Examples
     ///
@@ -702,7 +702,7 @@ pub trait FileTypeExt {
     /// ```
     #[stable(feature = "file_type_ext", since = "1.5.0")]
     fn is_block_device(&self) -> bool;
-    /// Returns whether this file type is a char device.
+    /// Returns `true` if this file type is a char device.
     ///
     /// # Examples
     ///
@@ -720,7 +720,7 @@ pub trait FileTypeExt {
     /// ```
     #[stable(feature = "file_type_ext", since = "1.5.0")]
     fn is_char_device(&self) -> bool;
-    /// Returns whether this file type is a fifo.
+    /// Returns `true` if this file type is a fifo.
     ///
     /// # Examples
     ///
@@ -738,7 +738,7 @@ pub trait FileTypeExt {
     /// ```
     #[stable(feature = "file_type_ext", since = "1.5.0")]
     fn is_fifo(&self) -> bool;
-    /// Returns whether this file type is a socket.
+    /// Returns `true` if this file type is a socket.
     ///
     /// # Examples
     ///
@@ -805,9 +805,9 @@ impl DirEntryExt for fs::DirEntry {
 /// # Note
 ///
 /// On Windows, you must specify whether a symbolic link points to a file
-/// or directory.  Use `os::windows::fs::symlink_file` to create a
+/// or directory. Use `os::windows::fs::symlink_file` to create a
 /// symbolic link to a file, or `os::windows::fs::symlink_dir` to create a
-/// symbolic link to a directory.  Additionally, the process must have
+/// symbolic link to a directory. Additionally, the process must have
 /// `SeCreateSymbolicLinkPrivilege` in order to be able to create a
 /// symbolic link.
 ///
diff --git a/src/libstd/sys/unix/ext/mod.rs b/src/libstd/sys/unix/ext/mod.rs
index 36e9370b71318..ccbac1a3e4b59 100644
--- a/src/libstd/sys/unix/ext/mod.rs
+++ b/src/libstd/sys/unix/ext/mod.rs
@@ -1,4 +1,4 @@
-//! Experimental extensions to `std` for Unix platforms.
+//! Platform-specific extensions to `std` for Unix platforms.
 //!
 //! Provides access to platform-level information on Unix platforms, and
 //! exposes Unix-specific functions that would otherwise be inappropriate as
diff --git a/src/libstd/sys/unix/ext/net.rs b/src/libstd/sys/unix/ext/net.rs
index a3ae5943f6038..acc064acfcd29 100644
--- a/src/libstd/sys/unix/ext/net.rs
+++ b/src/libstd/sys/unix/ext/net.rs
@@ -134,7 +134,7 @@ impl SocketAddr {
         })
     }
 
-    /// Returns true if and only if the address is unnamed.
+    /// Returns `true` if the address is unnamed.
     ///
     /// # Examples
     ///
@@ -516,7 +516,7 @@ impl UnixStream {
     /// ```
     ///
     /// # Platform specific
-    /// On Redox this always returns None.
+    /// On Redox this always returns `None`.
     #[stable(feature = "unix_socket", since = "1.10.0")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.0.take_error()
@@ -841,7 +841,7 @@ impl UnixListener {
     /// ```
     ///
     /// # Platform specific
-    /// On Redox this always returns None.
+    /// On Redox this always returns `None`.
     #[stable(feature = "unix_socket", since = "1.10.0")]
     pub fn take_error(&self) -> io::Result<Option<io::Error>> {
         self.0.take_error()
@@ -1047,7 +1047,7 @@ impl UnixDatagram {
         Ok(UnixDatagram(inner))
     }
 
-    /// Create an unnamed pair of connected sockets.
+    /// Creates an unnamed pair of connected sockets.
     ///
     /// Returns two `UnixDatagrams`s which are connected to each other.
     ///
diff --git a/src/libstd/sys/unix/ext/process.rs b/src/libstd/sys/unix/ext/process.rs
index 0282aaae90923..b487bb889bafa 100644
--- a/src/libstd/sys/unix/ext/process.rs
+++ b/src/libstd/sys/unix/ext/process.rs
@@ -13,13 +13,13 @@ use sys_common::{AsInnerMut, AsInner, FromInner, IntoInner};
 /// [`process::Command`]: ../../../../std/process/struct.Command.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait CommandExt {
-    /// Sets the child process's user id. This translates to a
+    /// Sets the child process's user ID. This translates to a
     /// `setuid` call in the child process. Failure in the `setuid`
     /// call will cause the spawn to fail.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn uid(&mut self, id: u32) -> &mut process::Command;
 
-    /// Similar to `uid`, but sets the group id of the child process. This has
+    /// Similar to `uid`, but sets the group ID of the child process. This has
     /// the same semantics as the `uid` field.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn gid(&mut self, id: u32) -> &mut process::Command;
@@ -36,7 +36,7 @@ pub trait CommandExt {
     /// will be called and the spawn operation will immediately return with a
     /// failure.
     ///
-    /// # Notes
+    /// # Notes and Safety
     ///
     /// This closure will be run in the context of the child process after a
     /// `fork`. This primarily means that any modifications made to memory on
@@ -45,12 +45,32 @@ pub trait CommandExt {
     /// like `malloc` or acquiring a mutex are not guaranteed to work (due to
     /// other threads perhaps still running when the `fork` was run).
     ///
+    /// This also means that all resources such as file descriptors and
+    /// memory-mapped regions got duplicated. It is your responsibility to make
+    /// sure that the closure does not violate library invariants by making
+    /// invalid use of these duplicates.
+    ///
     /// When this closure is run, aspects such as the stdio file descriptors and
     /// working directory have successfully been changed, so output to these
     /// locations may not appear where intended.
+    #[stable(feature = "process_pre_exec", since = "1.34.0")]
+    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
+        where F: FnMut() -> io::Result<()> + Send + Sync + 'static;
+
+    /// Schedules a closure to be run just before the `exec` function is
+    /// invoked.
+    ///
+    /// This method is stable and usable, but it should be unsafe. To fix
+    /// that, it got deprecated in favor of the unsafe [`pre_exec`].
+    ///
+    /// [`pre_exec`]: #tymethod.pre_exec
     #[stable(feature = "process_exec", since = "1.15.0")]
+    #[rustc_deprecated(since = "1.37.0", reason = "should be unsafe, use `pre_exec` instead")]
     fn before_exec<F>(&mut self, f: F) -> &mut process::Command
-        where F: FnMut() -> io::Result<()> + Send + Sync + 'static;
+        where F: FnMut() -> io::Result<()> + Send + Sync + 'static
+    {
+        unsafe { self.pre_exec(f) }
+    }
 
     /// Performs all the required setup by this `Command`, followed by calling
     /// the `execvp` syscall.
@@ -97,10 +117,10 @@ impl CommandExt for process::Command {
         self
     }
 
-    fn before_exec<F>(&mut self, f: F) -> &mut process::Command
+    unsafe fn pre_exec<F>(&mut self, f: F) -> &mut process::Command
         where F: FnMut() -> io::Result<()> + Send + Sync + 'static
     {
-        self.as_inner_mut().before_exec(Box::new(f));
+        self.as_inner_mut().pre_exec(Box::new(f));
         self
     }
 
diff --git a/src/libstd/sys/unix/fast_thread_local.rs b/src/libstd/sys/unix/fast_thread_local.rs
index d48d701dd50ea..742ffd12b883d 100644
--- a/src/libstd/sys/unix/fast_thread_local.rs
+++ b/src/libstd/sys/unix/fast_thread_local.rs
@@ -33,30 +33,57 @@ pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
     register_dtor_fallback(t, dtor);
 }
 
-// macOS's analog of the above linux function is this _tlv_atexit function.
-// The disassembly of thread_local globals in C++ (at least produced by
-// clang) will have this show up in the output.
+// This implementation is very similar to register_dtor_fallback in
+// sys_common/thread_local.rs. The main difference is that we want to hook into
+// macOS's analog of the above linux function, _tlv_atexit. OSX will run the
+// registered dtors before any TLS slots get freed, and when the main thread
+// exits.
+//
+// Unfortunately, calling _tlv_atexit while tls dtors are running is UB. The
+// workaround below is to register, via _tlv_atexit, a custom DTOR list once per
+// thread. thread_local dtors are pushed to the DTOR list without calling
+// _tlv_atexit.
 #[cfg(target_os = "macos")]
 pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
+    use cell::Cell;
+    use ptr;
+
+    #[thread_local]
+    static REGISTERED: Cell<bool> = Cell::new(false);
+    if !REGISTERED.get() {
+        _tlv_atexit(run_dtors, ptr::null_mut());
+        REGISTERED.set(true);
+    }
+
+    type List = Vec<(*mut u8, unsafe extern fn(*mut u8))>;
+
+    #[thread_local]
+    static DTORS: Cell<*mut List> = Cell::new(ptr::null_mut());
+    if DTORS.get().is_null() {
+        let v: Box<List> = box Vec::new();
+        DTORS.set(Box::into_raw(v));
+    }
+
     extern {
         fn _tlv_atexit(dtor: unsafe extern fn(*mut u8),
                        arg: *mut u8);
     }
-    _tlv_atexit(dtor, t);
+
+    let list: &mut List = &mut *DTORS.get();
+    list.push((t, dtor));
+
+    unsafe extern fn run_dtors(_: *mut u8) {
+        let mut ptr = DTORS.replace(ptr::null_mut());
+        while !ptr.is_null() {
+            let list = Box::from_raw(ptr);
+            for (ptr, dtor) in list.into_iter() {
+                dtor(ptr);
+            }
+            ptr = DTORS.replace(ptr::null_mut());
+        }
+    }
 }
 
 pub fn requires_move_before_drop() -> bool {
-    // The macOS implementation of TLS apparently had an odd aspect to it
-    // where the pointer we have may be overwritten while this destructor
-    // is running. Specifically if a TLS destructor re-accesses TLS it may
-    // trigger a re-initialization of all TLS variables, paving over at
-    // least some destroyed ones with initial values.
-    //
-    // This means that if we drop a TLS value in place on macOS that we could
-    // revert the value to its original state halfway through the
-    // destructor, which would be bad!
-    //
-    // Hence, we use `ptr::read` on macOS (to move to a "safe" location)
-    // instead of drop_in_place.
-    cfg!(target_os = "macos")
+    false
 }
diff --git a/src/libstd/sys/unix/pipe.rs b/src/libstd/sys/unix/pipe.rs
index 91793a0d5ec3f..a746d982c6ca9 100644
--- a/src/libstd/sys/unix/pipe.rs
+++ b/src/libstd/sys/unix/pipe.rs
@@ -1,7 +1,7 @@
 use io;
 use libc::{self, c_int};
 use mem;
-use sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
+use sync::atomic::{AtomicBool, Ordering};
 use sys::fd::FileDesc;
 use sys::{cvt, cvt_r};
 
@@ -13,7 +13,7 @@ pub struct AnonPipe(FileDesc);
 
 pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
     syscall! { fn pipe2(fds: *mut c_int, flags: c_int) -> c_int }
-    static INVALID: AtomicBool = ATOMIC_BOOL_INIT;
+    static INVALID: AtomicBool = AtomicBool::new(false);
 
     let mut fds = [0; 2];
 
diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
index 2c55813c5cd39..7fa256e59b2db 100644
--- a/src/libstd/sys/unix/process/process_common.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -149,8 +149,10 @@ impl Command {
         &mut self.closures
     }
 
-    pub fn before_exec(&mut self,
-                       f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>) {
+    pub unsafe fn pre_exec(
+        &mut self,
+        f: Box<dyn FnMut() -> io::Result<()> + Send + Sync>,
+    ) {
         self.closures.push(f);
     }
 
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
index f0f8032b4b5c7..6fbbbb349b171 100644
--- a/src/libstd/sys/unix/process/process_unix.rs
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -281,8 +281,7 @@ impl Command {
         use mem;
         use sys;
 
-        if self.get_cwd().is_some() ||
-            self.get_gid().is_some() ||
+        if self.get_gid().is_some() ||
             self.get_uid().is_some() ||
             self.env_saw_path() ||
             self.get_closures().len() != 0 {
@@ -301,6 +300,24 @@ impl Command {
             }
         }
 
+        // Solaris and glibc 2.29+ can set a new working directory, and maybe
+        // others will gain this non-POSIX function too. We'll check for this
+        // weak symbol as soon as it's needed, so we can return early otherwise
+        // to do a manual chdir before exec.
+        weak! {
+            fn posix_spawn_file_actions_addchdir_np(
+                *mut libc::posix_spawn_file_actions_t,
+                *const libc::c_char
+            ) -> libc::c_int
+        }
+        let addchdir = match self.get_cwd() {
+            Some(cwd) => match posix_spawn_file_actions_addchdir_np.get() {
+                Some(f) => Some((f, cwd)),
+                None => return Ok(None),
+            },
+            None => None,
+        };
+
         let mut p = Process { pid: 0, status: None };
 
         struct PosixSpawnFileActions(libc::posix_spawn_file_actions_t);
@@ -345,6 +362,9 @@ impl Command {
                                                            fd,
                                                            libc::STDERR_FILENO))?;
             }
+            if let Some((f, cwd)) = addchdir {
+                cvt(f(&mut file_actions.0, cwd.as_ptr()))?;
+            }
 
             let mut set: libc::sigset_t = mem::uninitialized();
             cvt(libc::sigemptyset(&mut set))?;
@@ -383,7 +403,7 @@ impl Command {
 // Processes
 ////////////////////////////////////////////////////////////////////////////////
 
-/// The unique id of the process (this should never be negative).
+/// The unique ID of the process (this should never be negative).
 pub struct Process {
     pid: pid_t,
     status: Option<ExitStatus>,
diff --git a/src/libstd/sys/unix/stdio.rs b/src/libstd/sys/unix/stdio.rs
index 8a6b7b5f876ff..715f2eafb2d9b 100644
--- a/src/libstd/sys/unix/stdio.rs
+++ b/src/libstd/sys/unix/stdio.rs
@@ -12,7 +12,7 @@ impl Stdin {
     pub fn read(&self, data: &mut [u8]) -> io::Result<usize> {
         let fd = FileDesc::new(libc::STDIN_FILENO);
         let ret = fd.read(data);
-        fd.into_raw();
+        fd.into_raw(); // do not close this FD
         ret
     }
 }
@@ -23,7 +23,7 @@ impl Stdout {
     pub fn write(&self, data: &[u8]) -> io::Result<usize> {
         let fd = FileDesc::new(libc::STDOUT_FILENO);
         let ret = fd.write(data);
-        fd.into_raw();
+        fd.into_raw(); // do not close this FD
         ret
     }
 
@@ -38,7 +38,7 @@ impl Stderr {
     pub fn write(&self, data: &[u8]) -> io::Result<usize> {
         let fd = FileDesc::new(libc::STDERR_FILENO);
         let ret = fd.write(data);
-        fd.into_raw();
+        fd.into_raw(); // do not close this FD
         ret
     }
 
diff --git a/src/libstd/sys/windows/ext/ffi.rs b/src/libstd/sys/windows/ext/ffi.rs
index eb27891930749..6508c0cf447d1 100644
--- a/src/libstd/sys/windows/ext/ffi.rs
+++ b/src/libstd/sys/windows/ext/ffi.rs
@@ -3,19 +3,19 @@
 //! # Overview
 //!
 //! For historical reasons, the Windows API uses a form of potentially
-//! ill-formed UTF-16 encoding for strings.  Specifically, the 16-bit
+//! ill-formed UTF-16 encoding for strings. Specifically, the 16-bit
 //! code units in Windows strings may contain [isolated surrogate code
-//! points which are not paired together][ill-formed-utf-16].  The
+//! points which are not paired together][ill-formed-utf-16]. The
 //! Unicode standard requires that surrogate code points (those in the
 //! range U+D800 to U+DFFF) always be *paired*, because in the UTF-16
 //! encoding a *surrogate code unit pair* is used to encode a single
-//! character.  For compatibility with code that does not enforce
+//! character. For compatibility with code that does not enforce
 //! these pairings, Windows does not enforce them, either.
 //!
 //! While it is not always possible to convert such a string losslessly into
 //! a valid UTF-16 string (or even UTF-8), it is often desirable to be
 //! able to round-trip such a string from and to Windows APIs
-//! losslessly.  For example, some Rust code may be "bridging" some
+//! losslessly. For example, some Rust code may be "bridging" some
 //! Windows APIs together, just passing `WCHAR` strings among those
 //! APIs without ever really looking into the strings.
 //!
@@ -28,16 +28,16 @@
 //! # `OsStringExt` and `OsStrExt`
 //!
 //! [`OsString`] is the Rust wrapper for owned strings in the
-//! preferred representation of the operating system.  On Windows,
+//! preferred representation of the operating system. On Windows,
 //! this struct gets augmented with an implementation of the
-//! [`OsStringExt`] trait, which has a [`from_wide`] method.  This
+//! [`OsStringExt`] trait, which has a [`from_wide`] method. This
 //! lets you create an [`OsString`] from a `&[u16]` slice; presumably
 //! you get such a slice out of a `WCHAR` Windows API.
 //!
 //! Similarly, [`OsStr`] is the Rust wrapper for borrowed strings from
-//! preferred representation of the operating system.  On Windows, the
+//! preferred representation of the operating system. On Windows, the
 //! [`OsStrExt`] trait provides the [`encode_wide`] method, which
-//! outputs an [`EncodeWide`] iterator.  You can [`collect`] this
+//! outputs an [`EncodeWide`] iterator. You can [`collect`] this
 //! iterator, for example, to obtain a `Vec<u16>`; you can later get a
 //! pointer to this vector's contents and feed it to Windows APIs.
 //!
diff --git a/src/libstd/sys/windows/ext/fs.rs b/src/libstd/sys/windows/ext/fs.rs
index 6342af46daf0a..89038da6295f2 100644
--- a/src/libstd/sys/windows/ext/fs.rs
+++ b/src/libstd/sys/windows/ext/fs.rs
@@ -441,10 +441,10 @@ impl MetadataExt for Metadata {
 /// [`FileType`]: ../../../../std/fs/struct.FileType.html
 #[unstable(feature = "windows_file_type_ext", issue = "0")]
 pub trait FileTypeExt {
-    /// Returns whether this file type is a symbolic link that is also a directory.
+    /// Returns `true` if this file type is a symbolic link that is also a directory.
     #[unstable(feature = "windows_file_type_ext", issue = "0")]
     fn is_symlink_dir(&self) -> bool;
-    /// Returns whether this file type is a symbolic link that is also a file.
+    /// Returns `true` if this file type is a symbolic link that is also a file.
     #[unstable(feature = "windows_file_type_ext", issue = "0")]
     fn is_symlink_file(&self) -> bool;
 }
diff --git a/src/libstd/sys/windows/ext/io.rs b/src/libstd/sys/windows/ext/io.rs
index 76143dee46463..fbe0426ce5a8c 100644
--- a/src/libstd/sys/windows/ext/io.rs
+++ b/src/libstd/sys/windows/ext/io.rs
@@ -16,7 +16,7 @@ pub type RawHandle = raw::HANDLE;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub type RawSocket = raw::SOCKET;
 
-/// Extract raw handles.
+/// Extracts raw handles.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRawHandle {
     /// Extracts the raw handle, without taking any ownership.
@@ -98,7 +98,7 @@ impl IntoRawHandle for fs::File {
     }
 }
 
-/// Extract raw sockets.
+/// Extracts raw sockets.
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRawSocket {
     /// Extracts the underlying raw socket from this object.
@@ -106,7 +106,7 @@ pub trait AsRawSocket {
     fn as_raw_socket(&self) -> RawSocket;
 }
 
-/// Create I/O objects from raw sockets.
+/// Creates I/O objects from raw sockets.
 #[stable(feature = "from_raw_os", since = "1.1.0")]
 pub trait FromRawSocket {
     /// Creates a new I/O object from the given raw socket.
diff --git a/src/libstd/sys/windows/os.rs b/src/libstd/sys/windows/os.rs
index 5f478827b43b1..7399dd41a41cf 100644
--- a/src/libstd/sys/windows/os.rs
+++ b/src/libstd/sys/windows/os.rs
@@ -1,4 +1,4 @@
-//! Implementation of `std::os` functionality for Windows
+//! Implementation of `std::os` functionality for Windows.
 
 #![allow(nonstandard_style)]
 
diff --git a/src/libstd/sys/windows/pipe.rs b/src/libstd/sys/windows/pipe.rs
index 2b1dbe310eea4..d3b102268f632 100644
--- a/src/libstd/sys/windows/pipe.rs
+++ b/src/libstd/sys/windows/pipe.rs
@@ -7,7 +7,7 @@ use path::Path;
 use ptr;
 use slice;
 use sync::atomic::Ordering::SeqCst;
-use sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
+use sync::atomic::AtomicUsize;
 use sys::c;
 use sys::fs::{File, OpenOptions};
 use sys::handle::Handle;
@@ -148,7 +148,7 @@ pub fn anon_pipe(ours_readable: bool) -> io::Result<Pipes> {
 }
 
 fn random_number() -> usize {
-    static N: AtomicUsize = ATOMIC_USIZE_INIT;
+    static N: AtomicUsize = AtomicUsize::new(0);
     loop {
         if N.load(SeqCst) != 0 {
             return N.fetch_add(1, SeqCst)
@@ -282,7 +282,7 @@ impl<'a> AsyncPipe<'a> {
     /// Takes a parameter `wait` which indicates if this pipe is currently being
     /// read whether the function should block waiting for the read to complete.
     ///
-    /// Return values:
+    /// Returns values:
     ///
     /// * `true` - finished any pending read and the pipe is not at EOF (keep
     ///            going)
diff --git a/src/libstd/sys/windows/stdio.rs b/src/libstd/sys/windows/stdio.rs
index a4f4bd22cd921..0ea19a855257b 100644
--- a/src/libstd/sys/windows/stdio.rs
+++ b/src/libstd/sys/windows/stdio.rs
@@ -188,7 +188,9 @@ impl Output {
 }
 
 fn invalid_encoding() -> io::Error {
-    io::Error::new(io::ErrorKind::InvalidData, "text was not valid unicode")
+    io::Error::new(io::ErrorKind::InvalidData,
+                   "Windows stdio in console mode does not support non-UTF-8 byte sequences; \
+                    see https://github.com/rust-lang/rust/issues/23344")
 }
 
 fn readconsole_input_control(wakeup_mask: c::ULONG) -> c::CONSOLE_READCONSOLE_CONTROL {
diff --git a/src/libstd/sys/windows/time.rs b/src/libstd/sys/windows/time.rs
index 8e8e9195cf471..8a8159af2f1a6 100644
--- a/src/libstd/sys/windows/time.rs
+++ b/src/libstd/sys/windows/time.rs
@@ -1,10 +1,7 @@
 use cmp::Ordering;
 use fmt;
 use mem;
-use sync::Once;
 use sys::c;
-use sys::cvt;
-use sys_common::mul_div_u64;
 use time::Duration;
 use convert::TryInto;
 use core::hash::{Hash, Hasher};
@@ -14,7 +11,9 @@ const INTERVALS_PER_SEC: u64 = NANOS_PER_SEC / 100;
 
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug, Hash)]
 pub struct Instant {
-    t: c::LARGE_INTEGER,
+    // This duration is relative to an arbitrary microsecond epoch
+    // from the winapi QueryPerformanceCounter function.
+    t: Duration,
 }
 
 #[derive(Copy, Clone)]
@@ -33,11 +32,12 @@ pub const UNIX_EPOCH: SystemTime = SystemTime {
 
 impl Instant {
     pub fn now() -> Instant {
-        let mut t = Instant { t: 0 };
-        cvt(unsafe {
-            c::QueryPerformanceCounter(&mut t.t)
-        }).unwrap();
-        t
+        // High precision timing on windows operates in "Performance Counter"
+        // units, as returned by the WINAPI QueryPerformanceCounter function.
+        // These relate to seconds by a factor of QueryPerformanceFrequency.
+        // In order to keep unit conversions out of normal interval math, we
+        // measure in QPC units and immediately convert to nanoseconds.
+        perf_counter::PerformanceCounterInstant::now().into()
     }
 
     pub fn actually_monotonic() -> bool {
@@ -45,47 +45,31 @@ impl Instant {
     }
 
     pub const fn zero() -> Instant {
-        Instant { t: 0 }
+        Instant { t: Duration::from_secs(0) }
     }
 
     pub fn sub_instant(&self, other: &Instant) -> Duration {
-        // Values which are +- 1 need to be considered as basically the same
-        // units in time due to various measurement oddities, according to
-        // Windows [1]
-        //
-        // [1]:
-        // https://msdn.microsoft.com/en-us/library/windows/desktop
-        //                           /dn553408%28v=vs.85%29.aspx#guidance
-        if other.t > self.t && other.t - self.t == 1 {
+        // On windows there's a threshold below which we consider two timestamps
+        // equivalent due to measurement error. For more details + doc link,
+        // check the docs on epsilon.
+        let epsilon =
+            perf_counter::PerformanceCounterInstant::epsilon();
+        if other.t > self.t && other.t - self.t <= epsilon {
             return Duration::new(0, 0)
         }
-        let diff = (self.t as u64).checked_sub(other.t as u64)
-                                  .expect("specified instant was later than \
-                                           self");
-        let nanos = mul_div_u64(diff, NANOS_PER_SEC, frequency() as u64);
-        Duration::new(nanos / NANOS_PER_SEC, (nanos % NANOS_PER_SEC) as u32)
+        self.t.checked_sub(other.t)
+              .expect("specified instant was later than self")
     }
 
     pub fn checked_add_duration(&self, other: &Duration) -> Option<Instant> {
-        let freq = frequency() as u64;
-        let t = other.as_secs()
-            .checked_mul(freq)?
-            .checked_add(mul_div_u64(other.subsec_nanos() as u64, freq, NANOS_PER_SEC))?
-            .checked_add(self.t as u64)?;
         Some(Instant {
-            t: t as c::LARGE_INTEGER,
+            t: self.t.checked_add(*other)?
         })
     }
 
     pub fn checked_sub_duration(&self, other: &Duration) -> Option<Instant> {
-        let freq = frequency() as u64;
-        let t = other.as_secs().checked_mul(freq).and_then(|i| {
-            (self.t as u64).checked_sub(i)
-        }).and_then(|i| {
-            i.checked_sub(mul_div_u64(other.subsec_nanos() as u64, freq, NANOS_PER_SEC))
-        })?;
         Some(Instant {
-            t: t as c::LARGE_INTEGER,
+            t: self.t.checked_sub(*other)?
         })
     }
 }
@@ -186,14 +170,60 @@ fn intervals2dur(intervals: u64) -> Duration {
                   ((intervals % INTERVALS_PER_SEC) * 100) as u32)
 }
 
-fn frequency() -> c::LARGE_INTEGER {
-    static mut FREQUENCY: c::LARGE_INTEGER = 0;
-    static ONCE: Once = Once::new();
+mod perf_counter {
+    use super::{NANOS_PER_SEC};
+    use sync::Once;
+    use sys_common::mul_div_u64;
+    use sys::c;
+    use sys::cvt;
+    use time::Duration;
+
+    pub struct PerformanceCounterInstant {
+        ts: c::LARGE_INTEGER
+    }
+    impl PerformanceCounterInstant {
+        pub fn now() -> Self {
+            Self {
+                ts: query()
+            }
+        }
 
-    unsafe {
-        ONCE.call_once(|| {
-            cvt(c::QueryPerformanceFrequency(&mut FREQUENCY)).unwrap();
-        });
-        FREQUENCY
+        // Per microsoft docs, the margin of error for cross-thread time comparisons
+        // using QueryPerformanceCounter is 1 "tick" -- defined as 1/frequency().
+        // Reference: https://docs.microsoft.com/en-us/windows/desktop/SysInfo
+        //                   /acquiring-high-resolution-time-stamps
+        pub fn epsilon() -> Duration {
+            let epsilon = NANOS_PER_SEC / (frequency() as u64);
+            Duration::from_nanos(epsilon)
+        }
+    }
+    impl From<PerformanceCounterInstant> for super::Instant {
+        fn from(other: PerformanceCounterInstant) -> Self {
+            let freq = frequency() as u64;
+            let instant_nsec = mul_div_u64(other.ts as u64, NANOS_PER_SEC, freq);
+            Self {
+                t: Duration::from_nanos(instant_nsec)
+            }
+        }
+    }
+
+    fn frequency() -> c::LARGE_INTEGER {
+        static mut FREQUENCY: c::LARGE_INTEGER = 0;
+        static ONCE: Once = Once::new();
+
+        unsafe {
+            ONCE.call_once(|| {
+                cvt(c::QueryPerformanceFrequency(&mut FREQUENCY)).unwrap();
+            });
+            FREQUENCY
+        }
+    }
+
+    fn query() -> c::LARGE_INTEGER {
+        let mut qpc_value: c::LARGE_INTEGER = 0;
+        cvt(unsafe {
+            c::QueryPerformanceCounter(&mut qpc_value)
+        }).unwrap();
+        qpc_value
     }
 }
diff --git a/src/libstd/sys_common/backtrace.rs b/src/libstd/sys_common/backtrace.rs
index 57f31cb726c3c..347244b0e0d44 100644
--- a/src/libstd/sys_common/backtrace.rs
+++ b/src/libstd/sys_common/backtrace.rs
@@ -171,7 +171,7 @@ pub fn log_enabled() -> Option<PrintFormat> {
     val
 }
 
-/// Print the symbol of the backtrace frame.
+/// Prints the symbol of the backtrace frame.
 ///
 /// These output functions should now be used everywhere to ensure consistency.
 /// You may want to also use `output_fileline`.
@@ -203,7 +203,7 @@ fn output(w: &mut dyn Write, idx: usize, frame: Frame,
     w.write_all(b"\n")
 }
 
-/// Print the filename and line number of the backtrace frame.
+/// Prints the filename and line number of the backtrace frame.
 ///
 /// See also `output`.
 #[allow(dead_code)]
diff --git a/src/libstd/sys_common/bytestring.rs b/src/libstd/sys_common/bytestring.rs
index df57fae428167..915c17374ca02 100644
--- a/src/libstd/sys_common/bytestring.rs
+++ b/src/libstd/sys_common/bytestring.rs
@@ -31,7 +31,7 @@ mod tests {
     fn smoke() {
         struct Helper<'a>(&'a [u8]);
 
-        impl<'a> Debug for Helper<'a> {
+        impl Debug for Helper<'_> {
             fn fmt(&self, f: &mut Formatter) -> Result {
                 debug_fmt_bytestring(self.0, f)
             }
diff --git a/src/libstd/sys_common/mutex.rs b/src/libstd/sys_common/mutex.rs
index 536f1c70db23a..b47d8698c605b 100644
--- a/src/libstd/sys_common/mutex.rs
+++ b/src/libstd/sys_common/mutex.rs
@@ -76,7 +76,7 @@ pub fn raw(mutex: &Mutex) -> &imp::Mutex { &mutex.0 }
 /// A simple RAII utility for the above Mutex without the poisoning semantics.
 pub struct MutexGuard<'a>(&'a imp::Mutex);
 
-impl<'a> Drop for MutexGuard<'a> {
+impl Drop for MutexGuard<'_> {
     #[inline]
     fn drop(&mut self) {
         unsafe { self.0.unlock(); }
diff --git a/src/libstd/sys_common/remutex.rs b/src/libstd/sys_common/remutex.rs
index 9ef24433f1360..596e5d534c293 100644
--- a/src/libstd/sys_common/remutex.rs
+++ b/src/libstd/sys_common/remutex.rs
@@ -43,7 +43,7 @@ pub struct ReentrantMutexGuard<'a, T: 'a> {
     __poison: poison::Guard,
 }
 
-impl<'a, T> !marker::Send for ReentrantMutexGuard<'a, T> {}
+impl<T> !marker::Send for ReentrantMutexGuard<'_, T> {}
 
 
 impl<T> ReentrantMutex<T> {
@@ -138,7 +138,7 @@ impl<'mutex, T> ReentrantMutexGuard<'mutex, T> {
     }
 }
 
-impl<'mutex, T> Deref for ReentrantMutexGuard<'mutex, T> {
+impl<T> Deref for ReentrantMutexGuard<'_, T> {
     type Target = T;
 
     fn deref(&self) -> &T {
@@ -146,7 +146,7 @@ impl<'mutex, T> Deref for ReentrantMutexGuard<'mutex, T> {
     }
 }
 
-impl<'a, T> Drop for ReentrantMutexGuard<'a, T> {
+impl<T> Drop for ReentrantMutexGuard<'_, T> {
     #[inline]
     fn drop(&mut self) {
         unsafe {
@@ -212,7 +212,7 @@ mod tests {
     }
 
     pub struct Answer<'a>(pub ReentrantMutexGuard<'a, RefCell<u32>>);
-    impl<'a> Drop for Answer<'a> {
+    impl Drop for Answer<'_> {
         fn drop(&mut self) {
             *self.0.borrow_mut() = 42;
         }
diff --git a/src/libstd/sys_common/wtf8.rs b/src/libstd/sys_common/wtf8.rs
index 7f355fa7ec23b..6d4594fe295ca 100644
--- a/src/libstd/sys_common/wtf8.rs
+++ b/src/libstd/sys_common/wtf8.rs
@@ -34,7 +34,7 @@ const UTF8_REPLACEMENT_CHARACTER: &str = "\u{FFFD}";
 
 /// A Unicode code point: from U+0000 to U+10FFFF.
 ///
-/// Compare with the `char` type,
+/// Compares with the `char` type,
 /// which represents a Unicode scalar value:
 /// a code point that is not a surrogate (U+D800 to U+DFFF).
 #[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy)]
@@ -366,7 +366,7 @@ impl Wtf8Buf {
     }
 }
 
-/// Create a new WTF-8 string from an iterator of code points.
+/// Creates a new WTF-8 string from an iterator of code points.
 ///
 /// This replaces surrogate code point pairs with supplementary code points,
 /// like concatenating ill-formed UTF-16 strings effectively would.
@@ -664,7 +664,7 @@ impl Wtf8 {
 }
 
 
-/// Return a slice of the given string for the byte range [`begin`..`end`).
+/// Returns a slice of the given string for the byte range [`begin`..`end`).
 ///
 /// # Panics
 ///
@@ -686,7 +686,7 @@ impl ops::Index<ops::Range<usize>> for Wtf8 {
     }
 }
 
-/// Return a slice of the given string from byte `begin` to its end.
+/// Returns a slice of the given string from byte `begin` to its end.
 ///
 /// # Panics
 ///
@@ -706,7 +706,7 @@ impl ops::Index<ops::RangeFrom<usize>> for Wtf8 {
     }
 }
 
-/// Return a slice of the given string from its beginning to byte `end`.
+/// Returns a slice of the given string from its beginning to byte `end`.
 ///
 /// # Panics
 ///
diff --git a/src/libstd/tests/run-time-detect.rs b/src/libstd/tests/run-time-detect.rs
new file mode 100644
index 0000000000000..eacce1e568211
--- /dev/null
+++ b/src/libstd/tests/run-time-detect.rs
@@ -0,0 +1,100 @@
+//! These tests just check that the macros are available in libstd.
+
+#![cfg_attr(
+    any(
+        all(target_arch = "arm", any(target_os = "linux", target_os = "android")),
+        all(target_arch = "aarch64", any(target_os = "linux", target_os = "android")),
+        all(target_arch = "powerpc", target_os = "linux"),
+        all(target_arch = "powerpc64", target_os = "linux"),
+    ),
+    feature(stdsimd)
+)]
+
+#[test]
+#[cfg(all(target_arch = "arm",
+          any(target_os = "linux", target_os = "android")))]
+fn arm_linux() {
+    println!("neon: {}", is_arm_feature_detected!("neon"));
+    println!("pmull: {}", is_arm_feature_detected!("pmull"));
+}
+
+#[test]
+#[cfg(all(
+    target_arch = "aarch64",
+    any(target_os = "linux", target_os = "android")
+))]
+fn aarch64_linux() {
+    println!("fp: {}", is_aarch64_feature_detected!("fp"));
+    println!("fp16: {}", is_aarch64_feature_detected!("fp16"));
+    println!("neon: {}", is_aarch64_feature_detected!("neon"));
+    println!("asimd: {}", is_aarch64_feature_detected!("asimd"));
+    println!("sve: {}", is_aarch64_feature_detected!("sve"));
+    println!("crc: {}", is_aarch64_feature_detected!("crc"));
+    println!("crypto: {}", is_aarch64_feature_detected!("crypto"));
+    println!("lse: {}", is_aarch64_feature_detected!("lse"));
+    println!("rdm: {}", is_aarch64_feature_detected!("rdm"));
+    println!("rcpc: {}", is_aarch64_feature_detected!("rcpc"));
+    println!("dotprod: {}", is_aarch64_feature_detected!("dotprod"));
+}
+
+#[test]
+#[cfg(all(target_arch = "powerpc", target_os = "linux"))]
+fn powerpc_linux() {
+    println!("altivec: {}", is_powerpc_feature_detected!("altivec"));
+    println!("vsx: {}", is_powerpc_feature_detected!("vsx"));
+    println!("power8: {}", is_powerpc_feature_detected!("power8"));
+}
+
+#[test]
+#[cfg(all(target_arch = "powerpc64", target_os = "linux"))]
+fn powerpc64_linux() {
+    println!("altivec: {}", is_powerpc64_feature_detected!("altivec"));
+    println!("vsx: {}", is_powerpc64_feature_detected!("vsx"));
+    println!("power8: {}", is_powerpc64_feature_detected!("power8"));
+}
+
+#[test]
+#[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
+fn x86_all() {
+    println!("aes: {:?}", is_x86_feature_detected!("aes"));
+    println!("pcmulqdq: {:?}", is_x86_feature_detected!("pclmulqdq"));
+    println!("rdrand: {:?}", is_x86_feature_detected!("rdrand"));
+    println!("rdseed: {:?}", is_x86_feature_detected!("rdseed"));
+    println!("tsc: {:?}", is_x86_feature_detected!("tsc"));
+    println!("mmx: {:?}", is_x86_feature_detected!("mmx"));
+    println!("sse: {:?}", is_x86_feature_detected!("sse"));
+    println!("sse2: {:?}", is_x86_feature_detected!("sse2"));
+    println!("sse3: {:?}", is_x86_feature_detected!("sse3"));
+    println!("ssse3: {:?}", is_x86_feature_detected!("ssse3"));
+    println!("sse4.1: {:?}", is_x86_feature_detected!("sse4.1"));
+    println!("sse4.2: {:?}", is_x86_feature_detected!("sse4.2"));
+    println!("sse4a: {:?}", is_x86_feature_detected!("sse4a"));
+    println!("sha: {:?}", is_x86_feature_detected!("sha"));
+    println!("avx: {:?}", is_x86_feature_detected!("avx"));
+    println!("avx2: {:?}", is_x86_feature_detected!("avx2"));
+    println!("avx512f {:?}", is_x86_feature_detected!("avx512f"));
+    println!("avx512cd {:?}", is_x86_feature_detected!("avx512cd"));
+    println!("avx512er {:?}", is_x86_feature_detected!("avx512er"));
+    println!("avx512pf {:?}", is_x86_feature_detected!("avx512pf"));
+    println!("avx512bw {:?}", is_x86_feature_detected!("avx512bw"));
+    println!("avx512dq {:?}", is_x86_feature_detected!("avx512dq"));
+    println!("avx512vl {:?}", is_x86_feature_detected!("avx512vl"));
+    println!("avx512_ifma {:?}", is_x86_feature_detected!("avx512ifma"));
+    println!("avx512_vbmi {:?}", is_x86_feature_detected!("avx512vbmi"));
+    println!(
+        "avx512_vpopcntdq {:?}",
+        is_x86_feature_detected!("avx512vpopcntdq")
+    );
+    println!("fma: {:?}", is_x86_feature_detected!("fma"));
+    println!("bmi1: {:?}", is_x86_feature_detected!("bmi1"));
+    println!("bmi2: {:?}", is_x86_feature_detected!("bmi2"));
+    println!("abm: {:?}", is_x86_feature_detected!("abm"));
+    println!("lzcnt: {:?}", is_x86_feature_detected!("lzcnt"));
+    println!("tbm: {:?}", is_x86_feature_detected!("tbm"));
+    println!("popcnt: {:?}", is_x86_feature_detected!("popcnt"));
+    println!("fxsr: {:?}", is_x86_feature_detected!("fxsr"));
+    println!("xsave: {:?}", is_x86_feature_detected!("xsave"));
+    println!("xsaveopt: {:?}", is_x86_feature_detected!("xsaveopt"));
+    println!("xsaves: {:?}", is_x86_feature_detected!("xsaves"));
+    println!("xsavec: {:?}", is_x86_feature_detected!("xsavec"));
+}
diff --git a/src/libstd/thread/local.rs b/src/libstd/thread/local.rs
index efd231e017679..8207709e1f9f0 100644
--- a/src/libstd/thread/local.rs
+++ b/src/libstd/thread/local.rs
@@ -69,9 +69,6 @@ use mem;
 ///    destroyed, but not all platforms have this guard. Those platforms that do
 ///    not guard typically have a synthetic limit after which point no more
 ///    destructors are run.
-/// 3. On macOS, initializing TLS during destruction of other TLS slots can
-///    sometimes cancel *all* destructors for the current thread, whether or not
-///    the slots have already had their destructors run or not.
 ///
 /// [`with`]: ../../std/thread/struct.LocalKey.html#method.with
 /// [`thread_local!`]: ../../std/macro.thread_local.html
@@ -129,7 +126,8 @@ impl<T: 'static> fmt::Debug for LocalKey<T> {
 /// [`std::thread::LocalKey`]: ../std/thread/struct.LocalKey.html
 #[macro_export]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(thread_local_internals))]
 macro_rules! thread_local {
     // empty (base case for the recursion)
     () => {};
@@ -151,7 +149,10 @@ macro_rules! thread_local {
            reason = "should not be necessary",
            issue = "0")]
 #[macro_export]
-#[allow_internal_unstable]
+#[cfg_attr(stage0, allow_internal_unstable)]
+#[cfg_attr(not(stage0), allow_internal_unstable(
+    thread_local_internals, cfg_target_thread_local, thread_local,
+))]
 #[allow_internal_unsafe]
 macro_rules! __thread_local_inner {
     (@key $(#[$attr:meta])* $vis:vis $name:ident, $t:ty, $init:expr) => {
@@ -604,11 +605,8 @@ mod tests {
     }
 
     // Note that this test will deadlock if TLS destructors aren't run (this
-    // requires the destructor to be run to pass the test). macOS has a known bug
-    // where dtors-in-dtors may cancel other destructors, so we just ignore this
-    // test on macOS.
+    // requires the destructor to be run to pass the test).
     #[test]
-    #[cfg_attr(target_os = "macos", ignore)]
     fn dtors_in_dtors_in_dtors() {
         struct S1(Sender<()>);
         thread_local!(static K1: UnsafeCell<Option<S1>> = UnsafeCell::new(None));
diff --git a/src/libstd/thread/mod.rs b/src/libstd/thread/mod.rs
index a55b32c08a303..438ea3aa3f6a3 100644
--- a/src/libstd/thread/mod.rs
+++ b/src/libstd/thread/mod.rs
@@ -607,7 +607,7 @@ impl Builder {
 pub fn spawn<F, T>(f: F) -> JoinHandle<T> where
     F: FnOnce() -> T, F: Send + 'static, T: Send + 'static
 {
-    Builder::new().spawn(f).unwrap()
+    Builder::new().spawn(f).expect("failed to spawn thread")
 }
 
 /// Gets a handle to the thread that invokes it.
@@ -841,7 +841,7 @@ const NOTIFIED: usize = 2;
 /// let flag2 = Arc::clone(&flag);
 ///
 /// let parked_thread = thread::spawn(move || {
-///     // We want to wait until the flag is set.  We *could* just spin, but using
+///     // We want to wait until the flag is set. We *could* just spin, but using
 ///     // park/unpark is more efficient.
 ///     while !flag2.load(Ordering::Acquire) {
 ///         println!("Parking thread");
diff --git a/src/libstd/time.rs b/src/libstd/time.rs
index 507ea395c6c6c..e1c2b2b1d4f30 100644
--- a/src/libstd/time.rs
+++ b/src/libstd/time.rs
@@ -33,7 +33,7 @@ pub use core::time::{SECOND, MILLISECOND, MICROSECOND, NANOSECOND};
 /// instant when created, and are often useful for tasks such as measuring
 /// benchmarks or timing how long an operation takes.
 ///
-/// Note, however, that instants are not guaranteed to be **steady**.  In other
+/// Note, however, that instants are not guaranteed to be **steady**. In other
 /// words, each tick of the underlying clock may not be the same length (e.g.
 /// some seconds may be longer than others). An instant may jump forwards or
 /// experience time dilation (slow down or speed up), but it will never go
@@ -218,6 +218,52 @@ impl Instant {
         self.0.sub_instant(&earlier.0)
     }
 
+    /// Returns the amount of time elapsed from another instant to this one,
+    /// or None if that instant is earlier than this one.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(checked_duration_since)]
+    /// use std::time::{Duration, Instant};
+    /// use std::thread::sleep;
+    ///
+    /// let now = Instant::now();
+    /// sleep(Duration::new(1, 0));
+    /// let new_now = Instant::now();
+    /// println!("{:?}", new_now.checked_duration_since(now));
+    /// println!("{:?}", now.checked_duration_since(new_now)); // None
+    /// ```
+    #[unstable(feature = "checked_duration_since", issue = "58402")]
+    pub fn checked_duration_since(&self, earlier: Instant) -> Option<Duration> {
+        if self >= &earlier {
+            Some(self.0.sub_instant(&earlier.0))
+        } else {
+            None
+        }
+    }
+
+    /// Returns the amount of time elapsed from another instant to this one,
+    /// or zero duration if that instant is earlier than this one.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// #![feature(checked_duration_since)]
+    /// use std::time::{Duration, Instant};
+    /// use std::thread::sleep;
+    ///
+    /// let now = Instant::now();
+    /// sleep(Duration::new(1, 0));
+    /// let new_now = Instant::now();
+    /// println!("{:?}", new_now.saturating_duration_since(now));
+    /// println!("{:?}", now.saturating_duration_since(new_now)); // 0ns
+    /// ```
+    #[unstable(feature = "checked_duration_since", issue = "58402")]
+    pub fn saturating_duration_since(&self, earlier: Instant) -> Duration {
+        self.checked_duration_since(earlier).unwrap_or(Duration::new(0, 0))
+    }
+
     /// Returns the amount of time elapsed since this instant was created.
     ///
     /// # Panics
@@ -245,17 +291,17 @@ impl Instant {
     /// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
     /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
     /// otherwise.
-    #[unstable(feature = "time_checked_add", issue = "55940")]
+    #[stable(feature = "time_checked_add", since = "1.34.0")]
     pub fn checked_add(&self, duration: Duration) -> Option<Instant> {
-        self.0.checked_add_duration(&duration).map(|t| Instant(t))
+        self.0.checked_add_duration(&duration).map(Instant)
     }
 
     /// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
     /// `Instant` (which means it's inside the bounds of the underlying data structure), `None`
     /// otherwise.
-    #[unstable(feature = "time_checked_add", issue = "55940")]
+    #[stable(feature = "time_checked_add", since = "1.34.0")]
     pub fn checked_sub(&self, duration: Duration) -> Option<Instant> {
-        self.0.checked_sub_duration(&duration).map(|t| Instant(t))
+        self.0.checked_sub_duration(&duration).map(Instant)
     }
 }
 
@@ -418,17 +464,17 @@ impl SystemTime {
     /// Returns `Some(t)` where `t` is the time `self + duration` if `t` can be represented as
     /// `SystemTime` (which means it's inside the bounds of the underlying data structure), `None`
     /// otherwise.
-    #[unstable(feature = "time_checked_add", issue = "55940")]
+    #[stable(feature = "time_checked_add", since = "1.34.0")]
     pub fn checked_add(&self, duration: Duration) -> Option<SystemTime> {
-        self.0.checked_add_duration(&duration).map(|t| SystemTime(t))
+        self.0.checked_add_duration(&duration).map(SystemTime)
     }
 
     /// Returns `Some(t)` where `t` is the time `self - duration` if `t` can be represented as
     /// `SystemTime` (which means it's inside the bounds of the underlying data structure), `None`
     /// otherwise.
-    #[unstable(feature = "time_checked_add", issue = "55940")]
+    #[stable(feature = "time_checked_add", since = "1.34.0")]
     pub fn checked_sub(&self, duration: Duration) -> Option<SystemTime> {
-        self.0.checked_sub_duration(&duration).map(|t| SystemTime(t))
+        self.0.checked_sub_duration(&duration).map(SystemTime)
     }
 }
 
@@ -610,6 +656,15 @@ mod tests {
         assert_eq!(a + year, a.checked_add(year).unwrap());
     }
 
+    #[test]
+    fn instant_math_is_associative() {
+        let now = Instant::now();
+        let offset = Duration::from_millis(5);
+        // Changing the order of instant math shouldn't change the results,
+        // especially when the expression reduces to X + identity.
+        assert_eq!((now + offset) - now, (now - now) + offset);
+    }
+
     #[test]
     #[should_panic]
     fn instant_duration_panic() {
@@ -617,6 +672,20 @@ mod tests {
         (a - Duration::new(1, 0)).duration_since(a);
     }
 
+    #[test]
+    fn checked_instant_duration_nopanic() {
+        let a = Instant::now();
+        let ret = (a - Duration::new(1, 0)).checked_duration_since(a);
+        assert_eq!(ret, None);
+    }
+
+    #[test]
+    fn saturating_instant_duration_nopanic() {
+        let a = Instant::now();
+        let ret = (a - Duration::new(1, 0)).saturating_duration_since(a);
+        assert_eq!(ret, Duration::new(0,0));
+    }
+
     #[test]
     fn system_time_math() {
         let a = SystemTime::now();
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index fba2623e005d0..4a0bb0302ffbc 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "syntax"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "syntax"
@@ -14,7 +15,7 @@ serialize = { path = "../libserialize" }
 log = "0.4"
 scoped-tls = "0.1"
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 99ab9fbcf5fa0..9c4945d74dbfe 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -1,22 +1,23 @@
 // The Rust abstract syntax tree.
 
-pub use self::GenericArgs::*;
-pub use self::UnsafeSource::*;
-pub use symbol::{Ident, Symbol as Name};
-pub use util::parser::ExprPrecedence;
-
-use ext::hygiene::{Mark, SyntaxContext};
-use print::pprust;
-use ptr::P;
+pub use GenericArgs::*;
+pub use UnsafeSource::*;
+pub use crate::symbol::{Ident, Symbol as Name};
+pub use crate::util::parser::ExprPrecedence;
+
+use crate::ext::hygiene::{Mark, SyntaxContext};
+use crate::print::pprust;
+use crate::ptr::P;
+use crate::source_map::{dummy_spanned, respan, Spanned};
+use crate::symbol::{keywords, Symbol};
+use crate::tokenstream::TokenStream;
+use crate::ThinVec;
+
 use rustc_data_structures::indexed_vec::Idx;
 #[cfg(target_arch = "x86_64")]
 use rustc_data_structures::static_assert;
 use rustc_target::spec::abi::Abi;
-use source_map::{dummy_spanned, respan, Spanned};
-use symbol::{keywords, Symbol};
 use syntax_pos::{Span, DUMMY_SP};
-use tokenstream::{ThinTokenStream, TokenStream};
-use ThinVec;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::Lrc;
@@ -31,7 +32,7 @@ pub struct Label {
 }
 
 impl fmt::Debug for Label {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "label({:?})", self.ident)
     }
 }
@@ -43,7 +44,7 @@ pub struct Lifetime {
 }
 
 impl fmt::Debug for Lifetime {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
             "lifetime({}: {})",
@@ -74,13 +75,13 @@ impl<'a> PartialEq<&'a str> for Path {
 }
 
 impl fmt::Debug for Path {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "path({})", pprust::path_to_string(self))
     }
 }
 
 impl fmt::Display for Path {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", pprust::path_to_string(self))
     }
 }
@@ -128,18 +129,32 @@ impl PathSegment {
     }
 }
 
-/// Arguments of a path segment.
+/// The arguments of a path segment.
 ///
 /// E.g., `<A, B>` as in `Foo<A, B>` or `(A, B)` as in `Foo(A, B)`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericArgs {
-    /// The `<'a, A,B,C>` in `foo::bar::baz::<'a, A,B,C>`
+    /// The `<'a, A, B, C>` in `foo::bar::baz::<'a, A, B, C>`.
     AngleBracketed(AngleBracketedArgs),
-    /// The `(A,B)` and `C` in `Foo(A,B) -> C`
-    Parenthesized(ParenthesisedArgs),
+    /// The `(A, B)` and `C` in `Foo(A, B) -> C`.
+    Parenthesized(ParenthesizedArgs),
 }
 
 impl GenericArgs {
+    pub fn is_parenthesized(&self) -> bool {
+        match *self {
+            Parenthesized(..) => true,
+            _ => false,
+        }
+    }
+
+    pub fn is_angle_bracketed(&self) -> bool {
+        match *self {
+            AngleBracketed(..) => true,
+            _ => false,
+        }
+    }
+
     pub fn span(&self) -> Span {
         match *self {
             AngleBracketed(ref data) => data.span,
@@ -152,18 +167,28 @@ impl GenericArgs {
 pub enum GenericArg {
     Lifetime(Lifetime),
     Type(P<Ty>),
+    Const(AnonConst),
 }
 
-/// A path like `Foo<'a, T>`
+impl GenericArg {
+    pub fn span(&self) -> Span {
+        match self {
+            GenericArg::Lifetime(lt) => lt.ident.span,
+            GenericArg::Type(ty) => ty.span,
+            GenericArg::Const(ct) => ct.value.span,
+        }
+    }
+}
+
+/// A path like `Foo<'a, T>`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, Default)]
 pub struct AngleBracketedArgs {
-    /// Overall span
+    /// The overall span.
     pub span: Span,
     /// The arguments for this path segment.
     pub args: Vec<GenericArg>,
     /// Bindings (equality constraints) on associated types, if present.
-    ///
-    /// E.g., `Foo<A=Bar>`.
+    /// E.g., `Foo<A = Bar>`.
     pub bindings: Vec<TypeBinding>,
 }
 
@@ -173,15 +198,15 @@ impl Into<Option<P<GenericArgs>>> for AngleBracketedArgs {
     }
 }
 
-impl Into<Option<P<GenericArgs>>> for ParenthesisedArgs {
+impl Into<Option<P<GenericArgs>>> for ParenthesizedArgs {
     fn into(self) -> Option<P<GenericArgs>> {
         Some(P(GenericArgs::Parenthesized(self)))
     }
 }
 
-/// A path like `Foo(A,B) -> C`
+/// A path like `Foo(A, B) -> C`.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
-pub struct ParenthesisedArgs {
+pub struct ParenthesizedArgs {
     /// Overall span
     pub span: Span,
 
@@ -192,9 +217,20 @@ pub struct ParenthesisedArgs {
     pub output: Option<P<Ty>>,
 }
 
+impl ParenthesizedArgs {
+    pub fn as_angle_bracketed_args(&self) -> AngleBracketedArgs {
+        AngleBracketedArgs {
+            span: self.span,
+            args: self.inputs.iter().cloned().map(|input| GenericArg::Type(input)).collect(),
+            bindings: vec![],
+        }
+    }
+}
+
 // hack to ensure that we don't try to access the private parts of `NodeId` in this module
 mod node_id_inner {
     use rustc_data_structures::indexed_vec::Idx;
+    use rustc_data_structures::newtype_index;
     newtype_index! {
         pub struct NodeId {
             ENCODABLE = custom
@@ -203,7 +239,7 @@ mod node_id_inner {
     }
 }
 
-pub use self::node_id_inner::NodeId;
+pub use node_id_inner::NodeId;
 
 impl NodeId {
     pub fn placeholder_from_mark(mark: Mark) -> Self {
@@ -216,7 +252,7 @@ impl NodeId {
 }
 
 impl fmt::Display for NodeId {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&self.as_u32(), f)
     }
 }
@@ -233,7 +269,7 @@ impl serialize::UseSpecializedDecodable for NodeId {
     }
 }
 
-/// Node id used to represent the root of the crate.
+/// `NodeId` used to represent the root of the crate.
 pub const CRATE_NODE_ID: NodeId = NodeId::from_u32_const(0);
 
 /// When parsing and doing expansions, we initially give all AST nodes this AST
@@ -270,13 +306,32 @@ impl GenericBound {
 
 pub type GenericBounds = Vec<GenericBound>;
 
+/// Specifies the enforced ordering for generic parameters. In the future,
+/// if we wanted to relax this order, we could override `PartialEq` and
+/// `PartialOrd`, to allow the kinds to be unordered.
+#[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy)]
+pub enum ParamKindOrd {
+    Lifetime,
+    Type,
+    Const,
+}
+
+impl fmt::Display for ParamKindOrd {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ParamKindOrd::Lifetime => "lifetime".fmt(f),
+            ParamKindOrd::Type => "type".fmt(f),
+            ParamKindOrd::Const => "const".fmt(f),
+        }
+    }
+}
+
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum GenericParamKind {
     /// A lifetime definition (e.g., `'a: 'b + 'c + 'd`).
     Lifetime,
-    Type {
-        default: Option<P<Ty>>,
-    },
+    Type { default: Option<P<Ty>> },
+    Const { ty: P<Ty> },
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
@@ -313,7 +368,7 @@ impl Default for Generics {
     }
 }
 
-/// A `where` clause in a definition
+/// A where-clause in a definition.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct WhereClause {
     pub id: NodeId,
@@ -321,7 +376,7 @@ pub struct WhereClause {
     pub span: Span,
 }
 
-/// A single predicate in a `where` clause
+/// A single predicate in a where-clause.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum WherePredicate {
     /// A type binding (e.g., `for<'c> Foo: Send + Clone + 'c`).
@@ -454,7 +509,7 @@ pub struct Pat {
 }
 
 impl fmt::Debug for Pat {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "pat({}: {})", self.id, pprust::pat_to_string(self))
     }
 }
@@ -585,19 +640,26 @@ pub enum PatKind {
     /// If the `..` pattern fragment is present, then `Option<usize>` denotes its position.
     /// `0 <= position <= subpats.len()`.
     Tuple(Vec<P<Pat>>, Option<usize>),
+
     /// A `box` pattern.
     Box(P<Pat>),
+
     /// A reference pattern (e.g., `&mut (a, b)`).
     Ref(P<Pat>, Mutability),
+
     /// A literal.
     Lit(P<Expr>),
+
     /// A range pattern (e.g., `1...2`, `1..=2` or `1..2`).
     Range(P<Expr>, P<Expr>, Spanned<RangeEnd>),
+
     /// `[a, b, ..i, y, z]` is represented as:
     ///     `PatKind::Slice(box [a, b], Some(i), box [y, z])`
     Slice(Vec<P<Pat>>, Option<P<Pat>>, Vec<P<Pat>>),
+
     /// Parentheses in patterns used for grouping (i.e., `(PAT)`).
     Paren(P<Pat>),
+
     /// A macro pattern; pre-expansion.
     Mac(Mac),
 }
@@ -652,7 +714,7 @@ pub enum BinOpKind {
 
 impl BinOpKind {
     pub fn to_string(&self) -> &'static str {
-        use self::BinOpKind::*;
+        use BinOpKind::*;
         match *self {
             Add => "+",
             Sub => "-",
@@ -689,7 +751,7 @@ impl BinOpKind {
     }
 
     pub fn is_comparison(&self) -> bool {
-        use self::BinOpKind::*;
+        use BinOpKind::*;
         match *self {
             Eq | Lt | Le | Ne | Gt | Ge => true,
             And | Or | Add | Sub | Mul | Div | Rem | BitXor | BitAnd | BitOr | Shl | Shr => false,
@@ -768,7 +830,7 @@ impl Stmt {
 }
 
 impl fmt::Debug for Stmt {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             f,
             "stmt({}: {})",
@@ -1006,7 +1068,7 @@ impl Expr {
 }
 
 impl fmt::Debug for Expr {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "expr({}: {})", self.id, pprust::expr_to_string(self))
     }
 }
@@ -1216,7 +1278,7 @@ pub type Mac = Spanned<Mac_>;
 pub struct Mac_ {
     pub path: Path,
     pub delim: MacDelimiter,
-    pub tts: ThinTokenStream,
+    pub tts: TokenStream,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Debug)]
@@ -1228,13 +1290,13 @@ pub enum MacDelimiter {
 
 impl Mac_ {
     pub fn stream(&self) -> TokenStream {
-        self.tts.stream()
+        self.tts.clone()
     }
 }
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct MacroDef {
-    pub tokens: ThinTokenStream,
+    pub tokens: TokenStream,
     pub legacy: bool,
 }
 
@@ -1285,6 +1347,8 @@ pub enum LitKind {
     FloatUnsuffixed(Symbol),
     /// A boolean literal.
     Bool(bool),
+    /// A recovered character literal that contains mutliple `char`s, most likely a typo.
+    Err(Symbol),
 }
 
 impl LitKind {
@@ -1321,6 +1385,7 @@ impl LitKind {
             | LitKind::ByteStr(..)
             | LitKind::Byte(..)
             | LitKind::Char(..)
+            | LitKind::Err(..)
             | LitKind::Int(_, LitIntType::Unsuffixed)
             | LitKind::FloatUnsuffixed(..)
             | LitKind::Bool(..) => true,
@@ -1411,13 +1476,13 @@ pub enum IntTy {
 }
 
 impl fmt::Debug for IntTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self, f)
     }
 }
 
 impl fmt::Display for IntTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.ty_to_string())
     }
 }
@@ -1492,13 +1557,13 @@ impl UintTy {
 }
 
 impl fmt::Debug for UintTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self, f)
     }
 }
 
 impl fmt::Display for UintTy {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", self.ty_to_string())
     }
 }
@@ -1520,7 +1585,7 @@ pub struct Ty {
 }
 
 impl fmt::Debug for Ty {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "type({})", pprust::ty_to_string(self))
     }
 }
@@ -1533,7 +1598,7 @@ pub struct BareFnTy {
     pub decl: P<FnDecl>,
 }
 
-/// The different kinds of types recognized by the compiler.
+/// The various kinds of type recognized by the compiler.
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum TyKind {
     /// A variable-length slice (`[T]`).
@@ -1805,7 +1870,7 @@ pub enum Defaultness {
 }
 
 impl fmt::Display for Unsafety {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(
             match *self {
                 Unsafety::Normal => "normal",
@@ -1825,7 +1890,7 @@ pub enum ImplPolarity {
 }
 
 impl fmt::Debug for ImplPolarity {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             ImplPolarity::Positive => "positive".fmt(f),
             ImplPolarity::Negative => "negative".fmt(f),
@@ -1835,7 +1900,7 @@ impl fmt::Debug for ImplPolarity {
 
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub enum FunctionRetTy {
-    /// Return type is not specified.
+    /// Returns type is not specified.
     ///
     /// Functions default to `()` and closures default to inference.
     /// Span points to where return type would be inserted.
@@ -1977,10 +2042,10 @@ pub struct Attribute {
 
 /// `TraitRef`s appear in impls.
 ///
-/// Resolve maps each `TraitRef`'s `ref_id` to its defining trait; that's all
+/// Resolution maps each `TraitRef`'s `ref_id` to its defining trait; that's all
 /// that the `ref_id` is for. The `impl_id` maps to the "self type" of this impl.
 /// If this impl is an `ItemKind::Impl`, the `impl_id` is redundant (it could be the
-/// same as the impl's node-id).
+/// same as the impl's `NodeId`).
 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
 pub struct TraitRef {
     pub path: Path,
@@ -2137,6 +2202,13 @@ pub struct Item {
     pub tokens: Option<TokenStream>,
 }
 
+impl Item {
+    /// Return the span that encompasses the attributes.
+    pub fn span_with_attributes(&self) -> Span {
+        self.attrs.iter().fold(self.span, |acc, attr| acc.to(attr.span()))
+    }
+}
+
 /// A function header.
 ///
 /// All the information between the visibility and the name of the function is
diff --git a/src/libsyntax/attr/builtin.rs b/src/libsyntax/attr/builtin.rs
index 15e480496f7a8..e84adc01cf04a 100644
--- a/src/libsyntax/attr/builtin.rs
+++ b/src/libsyntax/attr/builtin.rs
@@ -1,9 +1,10 @@
 //! Parsing and validation of builtin attributes
 
-use ast::{self, Attribute, MetaItem, Name, NestedMetaItemKind};
+use crate::ast::{self, Attribute, MetaItem, Name, NestedMetaItemKind};
+use crate::feature_gate::{Features, GatedCfg};
+use crate::parse::ParseSess;
+
 use errors::{Applicability, Handler};
-use feature_gate::{Features, GatedCfg};
-use parse::ParseSess;
 use syntax_pos::{symbol::Symbol, Span};
 
 use super::{list_contains_name, mark_used, MetaItemKind};
@@ -42,7 +43,7 @@ fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
             let mut err = struct_span_err!(diag, span, E0565, "{}", msg);
             if is_bytestr {
                 if let Ok(lint_str) = sess.source_map().span_to_snippet(span) {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "consider removing the prefix",
                         format!("{}", &lint_str[1..]),
@@ -63,6 +64,13 @@ pub enum InlineAttr {
     Never,
 }
 
+#[derive(Copy, Clone, Hash, PartialEq, RustcEncodable, RustcDecodable)]
+pub enum OptimizeAttr {
+    None,
+    Speed,
+    Size,
+}
+
 #[derive(Copy, Clone, PartialEq)]
 pub enum UnwindAttr {
     Allowed,
@@ -151,9 +159,11 @@ impl StabilityLevel {
 pub struct RustcDeprecation {
     pub since: Symbol,
     pub reason: Symbol,
+    /// A text snippet used to completely replace any use of the deprecated item in an expression.
+    pub suggestion: Option<Symbol>,
 }
 
-/// Check if `attrs` contains an attribute like `#![feature(feature_name)]`.
+/// Checks if `attrs` contains an attribute like `#![feature(feature_name)]`.
 /// This will not perform any "sanity checks" on the form of the attributes.
 pub fn contains_feature_attr(attrs: &[Attribute], feature_name: &str) -> bool {
     attrs.iter().any(|item| {
@@ -167,7 +177,7 @@ pub fn contains_feature_attr(attrs: &[Attribute], feature_name: &str) -> bool {
     })
 }
 
-/// Find the first stability attribute. `None` if none exists.
+/// Finds the first stability attribute. `None` if none exists.
 pub fn find_stability(sess: &ParseSess, attrs: &[Attribute],
                       item_sp: Span) -> Option<Stability> {
     find_stability_generic(sess, attrs.iter(), item_sp)
@@ -179,7 +189,7 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                                  -> Option<Stability>
     where I: Iterator<Item = &'a Attribute>
 {
-    use self::StabilityLevel::*;
+    use StabilityLevel::*;
 
     let mut stab: Option<Stability> = None;
     let mut rustc_depr: Option<RustcDeprecation> = None;
@@ -267,13 +277,14 @@ fn find_stability_generic<'a, I>(sess: &ParseSess,
                         continue 'outer
                     }
 
-                    get_meta!(since, reason);
+                    get_meta!(since, reason, suggestion);
 
                     match (since, reason) {
                         (Some(since), Some(reason)) => {
                             rustc_depr = Some(RustcDeprecation {
                                 since,
                                 reason,
+                                suggestion,
                             })
                         }
                         (None, _) => {
@@ -569,7 +580,7 @@ pub struct Deprecation {
     pub note: Option<Symbol>,
 }
 
-/// Find the deprecation attribute. `None` if none exists.
+/// Finds the deprecation attribute. `None` if none exists.
 pub fn find_deprecation(sess: &ParseSess, attrs: &[Attribute],
                         item_sp: Span) -> Option<Deprecation> {
     find_deprecation_generic(sess, attrs.iter(), item_sp)
@@ -585,81 +596,86 @@ fn find_deprecation_generic<'a, I>(sess: &ParseSess,
     let diagnostic = &sess.span_diagnostic;
 
     'outer: for attr in attrs_iter {
-        if attr.path != "deprecated" {
-            continue
+        if !attr.check_name("deprecated") {
+            continue;
         }
 
-        mark_used(attr);
-
         if depr.is_some() {
             span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes");
             break
         }
 
-        depr = if let Some(metas) = attr.meta_item_list() {
-            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
-                if item.is_some() {
-                    handle_errors(sess, meta.span, AttrError::MultipleItem(meta.name()));
-                    return false
-                }
-                if let Some(v) = meta.value_str() {
-                    *item = Some(v);
-                    true
-                } else {
-                    if let Some(lit) = meta.name_value_literal() {
-                        handle_errors(
-                            sess,
-                            lit.span,
-                            AttrError::UnsupportedLiteral(
-                                "literal in `deprecated` \
-                                value must be a string",
-                                lit.node.is_bytestr()
-                            ),
-                        );
-                    } else {
-                        span_err!(diagnostic, meta.span, E0551, "incorrect meta item");
+        let meta = attr.meta().unwrap();
+        depr = match &meta.node {
+            MetaItemKind::Word => Some(Deprecation { since: None, note: None }),
+            MetaItemKind::NameValue(..) => {
+                meta.value_str().map(|note| {
+                    Deprecation { since: None, note: Some(note) }
+                })
+            }
+            MetaItemKind::List(list) => {
+                let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
+                    if item.is_some() {
+                        handle_errors(sess, meta.span, AttrError::MultipleItem(meta.name()));
+                        return false
                     }
+                    if let Some(v) = meta.value_str() {
+                        *item = Some(v);
+                        true
+                    } else {
+                        if let Some(lit) = meta.name_value_literal() {
+                            handle_errors(
+                                sess,
+                                lit.span,
+                                AttrError::UnsupportedLiteral(
+                                    "literal in `deprecated` \
+                                    value must be a string",
+                                    lit.node.is_bytestr()
+                                ),
+                            );
+                        } else {
+                            span_err!(diagnostic, meta.span, E0551, "incorrect meta item");
+                        }
 
-                    false
-                }
-            };
+                        false
+                    }
+                };
 
-            let mut since = None;
-            let mut note = None;
-            for meta in metas {
-                match &meta.node {
-                    NestedMetaItemKind::MetaItem(mi) => {
-                        match &*mi.name().as_str() {
-                            "since" => if !get(mi, &mut since) { continue 'outer },
-                            "note" => if !get(mi, &mut note) { continue 'outer },
-                            _ => {
-                                handle_errors(
-                                    sess,
-                                    meta.span,
-                                    AttrError::UnknownMetaItem(mi.name(), &["since", "note"]),
-                                );
-                                continue 'outer
+                let mut since = None;
+                let mut note = None;
+                for meta in list {
+                    match &meta.node {
+                        NestedMetaItemKind::MetaItem(mi) => {
+                            match &*mi.name().as_str() {
+                                "since" => if !get(mi, &mut since) { continue 'outer },
+                                "note" => if !get(mi, &mut note) { continue 'outer },
+                                _ => {
+                                    handle_errors(
+                                        sess,
+                                        meta.span,
+                                        AttrError::UnknownMetaItem(mi.name(), &["since", "note"]),
+                                    );
+                                    continue 'outer
+                                }
                             }
                         }
-                    }
-                    NestedMetaItemKind::Literal(lit) => {
-                        handle_errors(
-                            sess,
-                            lit.span,
-                            AttrError::UnsupportedLiteral(
-                                "item in `deprecated` must be a key/value pair",
-                                false,
-                            ),
-                        );
-                        continue 'outer
+                        NestedMetaItemKind::Literal(lit) => {
+                            handle_errors(
+                                sess,
+                                lit.span,
+                                AttrError::UnsupportedLiteral(
+                                    "item in `deprecated` must be a key/value pair",
+                                    false,
+                                ),
+                            );
+                            continue 'outer
+                        }
                     }
                 }
-            }
 
-            Some(Deprecation {since: since, note: note})
-        } else {
-            Some(Deprecation{since: None, note: None})
-        }
+                Some(Deprecation { since, note })
+            }
+        };
     }
 
     depr
@@ -684,7 +700,7 @@ pub enum IntType {
 impl IntType {
     #[inline]
     pub fn is_signed(self) -> bool {
-        use self::IntType::*;
+        use IntType::*;
 
         match self {
             SignedInt(..) => true,
@@ -701,7 +717,7 @@ impl IntType {
 /// structure layout, `packed` to remove padding, and `transparent` to elegate representation
 /// concerns to the only non-ZST field.
 pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
-    use self::ReprAttr::*;
+    use ReprAttr::*;
 
     let mut acc = Vec::new();
     let diagnostic = &sess.span_diagnostic;
@@ -787,7 +803,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                                     "incorrect `repr(align)` attribute format");
                                 match value.node {
                                     ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => {
-                                        err.span_suggestion_with_applicability(
+                                        err.span_suggestion(
                                             item.span,
                                             "use parentheses instead",
                                             format!("align({})", int),
@@ -795,7 +811,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
                                         );
                                     }
                                     ast::LitKind::Str(s, _) => {
-                                        err.span_suggestion_with_applicability(
+                                        err.span_suggestion(
                                             item.span,
                                             "use parentheses instead",
                                             format!("align({})", s),
@@ -821,7 +837,7 @@ pub fn find_repr_attrs(sess: &ParseSess, attr: &Attribute) -> Vec<ReprAttr> {
 }
 
 fn int_type_of_word(s: &str) -> Option<IntType> {
-    use self::IntType::*;
+    use IntType::*;
 
     match s {
         "i8" => Some(SignedInt(ast::IntTy::I8)),
diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index f83c1ec145523..420f7426ad786 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -2,32 +2,36 @@
 
 mod builtin;
 
-pub use self::builtin::{
+pub use builtin::{
     cfg_matches, contains_feature_attr, eval_condition, find_crate_name, find_deprecation,
-    find_repr_attrs, find_stability, find_unwind_attr, Deprecation, InlineAttr, IntType, ReprAttr,
-    RustcDeprecation, Stability, StabilityLevel, UnwindAttr,
+    find_repr_attrs, find_stability, find_unwind_attr, Deprecation, InlineAttr, OptimizeAttr,
+    IntType, ReprAttr, RustcDeprecation, Stability, StabilityLevel, UnwindAttr,
 };
-pub use self::IntType::*;
-pub use self::ReprAttr::*;
-pub use self::StabilityLevel::*;
-
-use ast;
-use ast::{AttrId, Attribute, AttrStyle, Name, Ident, Path, PathSegment};
-use ast::{MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
-use ast::{Lit, LitKind, Expr, ExprKind, Item, Local, Stmt, StmtKind, GenericParam};
-use source_map::{BytePos, Spanned, respan, dummy_spanned};
+pub use IntType::*;
+pub use ReprAttr::*;
+pub use StabilityLevel::*;
+
+use crate::ast;
+use crate::ast::{AttrId, Attribute, AttrStyle, Name, Ident, Path, PathSegment};
+use crate::ast::{MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind};
+use crate::ast::{Lit, LitKind, Expr, ExprKind, Item, Local, Stmt, StmtKind, GenericParam};
+use crate::mut_visit::visit_clobber;
+use crate::source_map::{BytePos, Spanned, respan, dummy_spanned};
+use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
+use crate::parse::parser::Parser;
+use crate::parse::{self, ParseSess, PResult};
+use crate::parse::token::{self, Token};
+use crate::ptr::P;
+use crate::symbol::Symbol;
+use crate::ThinVec;
+use crate::tokenstream::{TokenStream, TokenTree, DelimSpan};
+use crate::GLOBALS;
+
+use log::debug;
 use syntax_pos::{FileName, Span};
-use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
-use parse::parser::Parser;
-use parse::{self, ParseSess, PResult};
-use parse::token::{self, Token};
-use ptr::P;
-use symbol::Symbol;
-use ThinVec;
-use tokenstream::{TokenStream, TokenTree, DelimSpan};
-use GLOBALS;
 
 use std::iter;
+use std::ops::DerefMut;
 
 pub fn mark_used(attr: &Attribute) {
     debug!("Marking {:?} as used.", attr);
@@ -81,7 +85,7 @@ impl NestedMetaItem {
         self.span
     }
 
-    /// Returns true if this list item is a MetaItem with a name of `name`.
+    /// Returns `true` if this list item is a MetaItem with a name of `name`.
     pub fn check_name(&self, name: &str) -> bool {
         self.meta_item().map_or(false, |meta_item| meta_item.check_name(name))
     }
@@ -161,6 +165,10 @@ fn name_from_path(path: &Path) -> Name {
 }
 
 impl Attribute {
+    /// Returns `true` if the attribute's path matches the argument. If it matches, then the
+    /// attribute is marked as used.
+    ///
+    /// To check the attribute name without marking it used, use the `path` field directly.
     pub fn check_name(&self, name: &str) -> bool {
         let matches = self.path == name;
         if matches {
@@ -268,7 +276,7 @@ impl MetaItem {
 }
 
 impl Attribute {
-    /// Extract the MetaItem from inside this Attribute.
+    /// Extracts the MetaItem from inside this Attribute.
     pub fn meta(&self) -> Option<MetaItem> {
         let mut tokens = self.tokens.trees().peekable();
         Some(MetaItem {
@@ -324,7 +332,7 @@ impl Attribute {
         })
     }
 
-    /// Convert self to a normal #[doc="foo"] comment, if it is a
+    /// Converts self to a normal #[doc="foo"] comment, if it is a
     /// comment like `///` or `/** */`. (Returns self unchanged for
     /// non-sugared doc attributes.)
     pub fn with_desugared_doc<T, F>(&self, f: F) -> T where
@@ -570,7 +578,7 @@ impl MetaItemKind {
             }
             Some(TokenTree::Delimited(_, delim, ref tts)) if delim == token::Paren => {
                 tokens.next();
-                tts.stream()
+                tts.clone()
             }
             _ => return Some(MetaItemKind::Word),
         };
@@ -630,7 +638,7 @@ impl LitKind {
 
         match *self {
             LitKind::Str(string, ast::StrStyle::Cooked) => {
-                let escaped = string.as_str().escape_default();
+                let escaped = string.as_str().escape_default().to_string();
                 Token::Literal(token::Lit::Str_(Symbol::intern(&escaped)), None)
             }
             LitKind::Str(string, ast::StrStyle::Raw(n)) => {
@@ -666,6 +674,7 @@ impl LitKind {
             } else {
                 "false"
             })), false),
+            LitKind::Err(val) => Token::Literal(token::Lit::Err(val), None),
         }
     }
 
@@ -694,13 +703,13 @@ impl LitKind {
 
 pub trait HasAttrs: Sized {
     fn attrs(&self) -> &[ast::Attribute];
-    fn map_attrs<F: FnOnce(Vec<ast::Attribute>) -> Vec<ast::Attribute>>(self, f: F) -> Self;
+    fn visit_attrs<F: FnOnce(&mut Vec<ast::Attribute>)>(&mut self, f: F);
 }
 
 impl<T: HasAttrs> HasAttrs for Spanned<T> {
     fn attrs(&self) -> &[ast::Attribute] { self.node.attrs() }
-    fn map_attrs<F: FnOnce(Vec<ast::Attribute>) -> Vec<ast::Attribute>>(self, f: F) -> Self {
-        respan(self.span, self.node.map_attrs(f))
+    fn visit_attrs<F: FnOnce(&mut Vec<ast::Attribute>)>(&mut self, f: F) {
+        self.node.visit_attrs(f);
     }
 }
 
@@ -708,7 +717,7 @@ impl HasAttrs for Vec<Attribute> {
     fn attrs(&self) -> &[Attribute] {
         self
     }
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
         f(self)
     }
 }
@@ -717,8 +726,12 @@ impl HasAttrs for ThinVec<Attribute> {
     fn attrs(&self) -> &[Attribute] {
         self
     }
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
-        f(self.into()).into()
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
+        visit_clobber(self, |this| {
+            let mut vec = this.into();
+            f(&mut vec);
+            vec.into()
+        });
     }
 }
 
@@ -726,8 +739,8 @@ impl<T: HasAttrs + 'static> HasAttrs for P<T> {
     fn attrs(&self) -> &[Attribute] {
         (**self).attrs()
     }
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
-        self.map(|t| t.map_attrs(f))
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
+        (**self).visit_attrs(f);
     }
 }
 
@@ -744,23 +757,27 @@ impl HasAttrs for StmtKind {
         }
     }
 
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
         match self {
-            StmtKind::Local(local) => StmtKind::Local(local.map_attrs(f)),
-            StmtKind::Item(..) => self,
-            StmtKind::Expr(expr) => StmtKind::Expr(expr.map_attrs(f)),
-            StmtKind::Semi(expr) => StmtKind::Semi(expr.map_attrs(f)),
-            StmtKind::Mac(mac) => StmtKind::Mac(mac.map(|(mac, style, attrs)| {
-                (mac, style, attrs.map_attrs(f))
-            })),
+            StmtKind::Local(local) => local.visit_attrs(f),
+            StmtKind::Item(..) => {}
+            StmtKind::Expr(expr) => expr.visit_attrs(f),
+            StmtKind::Semi(expr) => expr.visit_attrs(f),
+            StmtKind::Mac(mac) => {
+                let (_mac, _style, attrs) = mac.deref_mut();
+                attrs.visit_attrs(f);
+            }
         }
     }
 }
 
 impl HasAttrs for Stmt {
-    fn attrs(&self) -> &[ast::Attribute] { self.node.attrs() }
-    fn map_attrs<F: FnOnce(Vec<ast::Attribute>) -> Vec<ast::Attribute>>(self, f: F) -> Self {
-        Stmt { id: self.id, node: self.node.map_attrs(f), span: self.span }
+    fn attrs(&self) -> &[ast::Attribute] {
+        self.node.attrs()
+    }
+
+    fn visit_attrs<F: FnOnce(&mut Vec<ast::Attribute>)>(&mut self, f: F) {
+        self.node.visit_attrs(f);
     }
 }
 
@@ -769,9 +786,8 @@ impl HasAttrs for GenericParam {
         &self.attrs
     }
 
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(mut self, f: F) -> Self {
-        self.attrs = self.attrs.map_attrs(f);
-        self
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
+        self.attrs.visit_attrs(f);
     }
 }
 
@@ -782,11 +798,8 @@ macro_rules! derive_has_attrs {
                 &self.attrs
             }
 
-            fn map_attrs<F>(mut self, f: F) -> Self
-                where F: FnOnce(Vec<Attribute>) -> Vec<Attribute>,
-            {
-                self.attrs = self.attrs.map_attrs(f);
-                self
+            fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
+                self.attrs.visit_attrs(f);
             }
         }
     )* }
diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs
index 50e0056f3b9f1..4e4432a3f334d 100644
--- a/src/libsyntax/config.rs
+++ b/src/libsyntax/config.rs
@@ -1,20 +1,21 @@
-use attr::HasAttrs;
-use feature_gate::{
+use crate::attr::HasAttrs;
+use crate::feature_gate::{
     feature_err,
     EXPLAIN_STMT_ATTR_SYNTAX,
     Features,
     get_features,
     GateIssue,
 };
-use {fold, attr};
-use ast;
-use source_map::Spanned;
-use edition::Edition;
-use parse::{token, ParseSess};
-use smallvec::SmallVec;
-use errors::Applicability;
+use crate::attr;
+use crate::ast;
+use crate::edition::Edition;
+use crate::mut_visit::*;
+use crate::parse::{token, ParseSess};
+use crate::ptr::P;
+use crate::util::map_in_place::MapInPlace;
 
-use ptr::P;
+use errors::Applicability;
+use smallvec::SmallVec;
 
 /// A folder that strips out items that do not belong in the current configuration.
 pub struct StripUnconfigured<'a> {
@@ -64,8 +65,8 @@ macro_rules! configure {
 }
 
 impl<'a> StripUnconfigured<'a> {
-    pub fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
-        let node = self.process_cfg_attrs(node);
+    pub fn configure<T: HasAttrs>(&mut self, mut node: T) -> Option<T> {
+        self.process_cfg_attrs(&mut node);
         if self.in_cfg(node.attrs()) { Some(node) } else { None }
     }
 
@@ -75,10 +76,10 @@ impl<'a> StripUnconfigured<'a> {
     /// Gives compiler warnigns if any `cfg_attr` does not contain any
     /// attributes and is in the original source code. Gives compiler errors if
     /// the syntax of any `cfg_attr` is incorrect.
-    pub fn process_cfg_attrs<T: HasAttrs>(&mut self, node: T) -> T {
-        node.map_attrs(|attrs| {
-            attrs.into_iter().flat_map(|attr| self.process_cfg_attr(attr)).collect()
-        })
+    pub fn process_cfg_attrs<T: HasAttrs>(&mut self, node: &mut T) {
+        node.visit_attrs(|attrs| {
+            attrs.flat_map_in_place(|attr| self.process_cfg_attr(attr));
+        });
     }
 
     /// Parse and expand a single `cfg_attr` attribute into a list of attributes
@@ -87,7 +88,7 @@ impl<'a> StripUnconfigured<'a> {
     ///
     /// Gives a compiler warning when the `cfg_attr` contains no attributes and
     /// is in the original source file. Gives a compiler error if the syntax of
-    /// the attribute is incorrect
+    /// the attribute is incorrect.
     fn process_cfg_attr(&mut self, attr: ast::Attribute) -> Vec<ast::Attribute> {
         if !attr.check_name("cfg_attr") {
             return vec![attr];
@@ -145,7 +146,7 @@ impl<'a> StripUnconfigured<'a> {
         }
     }
 
-    /// Determine if a node with the given attributes should be included in this configuration.
+    /// Determines if a node with the given attributes should be included in this configuration.
     pub fn in_cfg(&mut self, attrs: &[ast::Attribute]) -> bool {
         attrs.iter().all(|attr| {
             if !is_cfg(attr) {
@@ -155,7 +156,7 @@ impl<'a> StripUnconfigured<'a> {
             let error = |span, msg, suggestion: &str| {
                 let mut err = self.sess.span_diagnostic.struct_span_err(span, msg);
                 if !suggestion.is_empty() {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "expected syntax is",
                         suggestion.into(),
@@ -217,76 +218,47 @@ impl<'a> StripUnconfigured<'a> {
         }
     }
 
-    pub fn configure_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
-        ast::ForeignMod {
-            abi: foreign_mod.abi,
-            items: foreign_mod.items.into_iter().filter_map(|item| self.configure(item)).collect(),
-        }
+    pub fn configure_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
+        let ast::ForeignMod { abi: _, items } = foreign_mod;
+        items.flat_map_in_place(|item| self.configure(item));
     }
 
-    fn configure_variant_data(&mut self, vdata: ast::VariantData) -> ast::VariantData {
+    fn configure_variant_data(&mut self, vdata: &mut ast::VariantData) {
         match vdata {
-            ast::VariantData::Struct(fields, id) => {
-                let fields = fields.into_iter().filter_map(|field| self.configure(field));
-                ast::VariantData::Struct(fields.collect(), id)
-            }
-            ast::VariantData::Tuple(fields, id) => {
-                let fields = fields.into_iter().filter_map(|field| self.configure(field));
-                ast::VariantData::Tuple(fields.collect(), id)
-            }
-            ast::VariantData::Unit(id) => ast::VariantData::Unit(id)
+            ast::VariantData::Struct(fields, _id) |
+            ast::VariantData::Tuple(fields, _id) =>
+                fields.flat_map_in_place(|field| self.configure(field)),
+            ast::VariantData::Unit(_id) => {}
         }
     }
 
-    pub fn configure_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
+    pub fn configure_item_kind(&mut self, item: &mut ast::ItemKind) {
         match item {
-            ast::ItemKind::Struct(def, generics) => {
-                ast::ItemKind::Struct(self.configure_variant_data(def), generics)
-            }
-            ast::ItemKind::Union(def, generics) => {
-                ast::ItemKind::Union(self.configure_variant_data(def), generics)
-            }
-            ast::ItemKind::Enum(def, generics) => {
-                let variants = def.variants.into_iter().filter_map(|v| {
-                    self.configure(v).map(|v| {
-                        Spanned {
-                            node: ast::Variant_ {
-                                ident: v.node.ident,
-                                attrs: v.node.attrs,
-                                data: self.configure_variant_data(v.node.data),
-                                disr_expr: v.node.disr_expr,
-                            },
-                            span: v.span
-                        }
-                    })
-                });
-                ast::ItemKind::Enum(ast::EnumDef {
-                    variants: variants.collect(),
-                }, generics)
+            ast::ItemKind::Struct(def, _generics) |
+            ast::ItemKind::Union(def, _generics) => self.configure_variant_data(def),
+            ast::ItemKind::Enum(ast::EnumDef { variants }, _generics) => {
+                variants.flat_map_in_place(|variant| self.configure(variant));
+                for variant in variants {
+                    self.configure_variant_data(&mut variant.node.data);
+                }
             }
-            item => item,
+            _ => {}
         }
     }
 
-    pub fn configure_expr_kind(&mut self, expr_kind: ast::ExprKind) -> ast::ExprKind {
+    pub fn configure_expr_kind(&mut self, expr_kind: &mut ast::ExprKind) {
         match expr_kind {
-            ast::ExprKind::Match(m, arms) => {
-                let arms = arms.into_iter().filter_map(|a| self.configure(a)).collect();
-                ast::ExprKind::Match(m, arms)
+            ast::ExprKind::Match(_m, arms) => {
+                arms.flat_map_in_place(|arm| self.configure(arm));
             }
-            ast::ExprKind::Struct(path, fields, base) => {
-                let fields = fields.into_iter()
-                    .filter_map(|field| {
-                        self.configure(field)
-                    })
-                    .collect();
-                ast::ExprKind::Struct(path, fields, base)
+            ast::ExprKind::Struct(_path, fields, _base) => {
+                fields.flat_map_in_place(|field| self.configure(field));
             }
-            _ => expr_kind,
+            _ => {}
         }
     }
 
-    pub fn configure_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
+    pub fn configure_expr(&mut self, expr: &mut P<ast::Expr>) {
         self.visit_expr_attrs(expr.attrs());
 
         // If an expr is valid to cfg away it will have been removed by the
@@ -294,8 +266,8 @@ impl<'a> StripUnconfigured<'a> {
         // Anything else is always required, and thus has to error out
         // in case of a cfg attr.
         //
-        // N.B., this is intentionally not part of the fold_expr() function
-        //     in order for fold_opt_expr() to be able to avoid this check
+        // N.B., this is intentionally not part of the visit_expr() function
+        //     in order for filter_map_expr() to be able to avoid this check
         if let Some(attr) = expr.attrs().iter().find(|a| is_cfg(a)) {
             let msg = "removing an expression is not supported in this position";
             self.sess.span_diagnostic.span_err(attr.span, msg);
@@ -304,30 +276,14 @@ impl<'a> StripUnconfigured<'a> {
         self.process_cfg_attrs(expr)
     }
 
-    pub fn configure_stmt(&mut self, stmt: ast::Stmt) -> Option<ast::Stmt> {
-        self.configure(stmt)
-    }
-
-    pub fn configure_struct_expr_field(&mut self, field: ast::Field) -> Option<ast::Field> {
-        self.configure(field)
-    }
-
-    pub fn configure_pat(&mut self, pattern: P<ast::Pat>) -> P<ast::Pat> {
-        pattern.map(|mut pattern| {
-            if let ast::PatKind::Struct(path, fields, etc) = pattern.node {
-                let fields = fields.into_iter()
-                    .filter_map(|field| {
-                        self.configure(field)
-                    })
-                    .collect();
-                pattern.node = ast::PatKind::Struct(path, fields, etc);
-            }
-            pattern
-        })
+    pub fn configure_pat(&mut self, pat: &mut P<ast::Pat>) {
+        if let ast::PatKind::Struct(_path, fields, _etc) = &mut pat.node {
+            fields.flat_map_in_place(|field| self.configure(field));
+        }
     }
 
-    // deny #[cfg] on generic parameters until we decide what to do with it.
-    // see issue #51279.
+    /// Denies `#[cfg]` on generic parameters until we decide what to do with it.
+    /// See issue #51279.
     pub fn disallow_cfg_on_generic_param(&mut self, param: &ast::GenericParam) {
         for attr in param.attrs() {
             let offending_attr = if attr.check_name("cfg") {
@@ -343,57 +299,54 @@ impl<'a> StripUnconfigured<'a> {
     }
 }
 
-impl<'a> fold::Folder for StripUnconfigured<'a> {
-    fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
-        let foreign_mod = self.configure_foreign_mod(foreign_mod);
-        fold::noop_fold_foreign_mod(foreign_mod, self)
+impl<'a> MutVisitor for StripUnconfigured<'a> {
+    fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
+        self.configure_foreign_mod(foreign_mod);
+        noop_visit_foreign_mod(foreign_mod, self);
     }
 
-    fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
-        let item = self.configure_item_kind(item);
-        fold::noop_fold_item_kind(item, self)
+    fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
+        self.configure_item_kind(item);
+        noop_visit_item_kind(item, self);
     }
 
-    fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
-        let mut expr = self.configure_expr(expr).into_inner();
-        expr.node = self.configure_expr_kind(expr.node);
-        P(fold::noop_fold_expr(expr, self))
+    fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
+        self.configure_expr(expr);
+        self.configure_expr_kind(&mut expr.node);
+        noop_visit_expr(expr, self);
     }
 
-    fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
-        let mut expr = configure!(self, expr).into_inner();
-        expr.node = self.configure_expr_kind(expr.node);
-        Some(P(fold::noop_fold_expr(expr, self)))
+    fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
+        let mut expr = configure!(self, expr);
+        self.configure_expr_kind(&mut expr.node);
+        noop_visit_expr(&mut expr, self);
+        Some(expr)
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
-        match self.configure_stmt(stmt) {
-            Some(stmt) => fold::noop_fold_stmt(stmt, self),
-            None => return SmallVec::new(),
-        }
+    fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
+        noop_flat_map_stmt(configure!(self, stmt), self)
     }
 
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
-        fold::noop_fold_item(configure!(self, item), self)
+    fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
+        noop_flat_map_item(configure!(self, item), self)
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]>
-    {
-        fold::noop_fold_impl_item(configure!(self, item), self)
+    fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
+        noop_flat_map_impl_item(configure!(self, item), self)
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
-        fold::noop_fold_trait_item(configure!(self, item), self)
+    fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
+        noop_flat_map_trait_item(configure!(self, item), self)
     }
 
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
+    fn visit_mac(&mut self, _mac: &mut ast::Mac) {
         // Don't configure interpolated AST (cf. issue #34171).
         // Interpolated AST will get configured once the surrounding tokens are parsed.
-        mac
     }
 
-    fn fold_pat(&mut self, pattern: P<ast::Pat>) -> P<ast::Pat> {
-        fold::noop_fold_pat(self.configure_pat(pattern), self)
+    fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
+        self.configure_pat(pat);
+        noop_visit_pat(pat, self)
     }
 }
 
diff --git a/src/libsyntax/diagnostics/metadata.rs b/src/libsyntax/diagnostics/metadata.rs
index abde3dca0f6b0..704135fe1d589 100644
--- a/src/libsyntax/diagnostics/metadata.rs
+++ b/src/libsyntax/diagnostics/metadata.rs
@@ -12,8 +12,9 @@ use std::error::Error;
 use rustc_serialize::json::as_json;
 
 use syntax_pos::{Span, FileName};
-use ext::base::ExtCtxt;
-use diagnostics::plugin::{ErrorMap, ErrorInfo};
+
+use crate::ext::base::ExtCtxt;
+use crate::diagnostics::plugin::{ErrorMap, ErrorInfo};
 
 /// JSON encodable/decodable version of `ErrorInfo`.
 #[derive(PartialEq, RustcDecodable, RustcEncodable)]
@@ -33,8 +34,8 @@ pub struct ErrorLocation {
 }
 
 impl ErrorLocation {
-    /// Create an error location from a span.
-    pub fn from_span(ecx: &ExtCtxt, sp: Span) -> ErrorLocation {
+    /// Creates an error location from a span.
+    pub fn from_span(ecx: &ExtCtxt<'_>, sp: Span) -> ErrorLocation {
         let loc = ecx.source_map().lookup_char_pos_adj(sp.lo());
         ErrorLocation {
             filename: loc.filename,
@@ -43,7 +44,7 @@ impl ErrorLocation {
     }
 }
 
-/// Get the directory where metadata for a given `prefix` should be stored.
+/// Gets the directory where metadata for a given `prefix` should be stored.
 ///
 /// See `output_metadata`.
 pub fn get_metadata_dir(prefix: &str) -> PathBuf {
@@ -62,7 +63,7 @@ fn get_metadata_path(directory: PathBuf, name: &str) -> PathBuf {
 ///
 /// For our current purposes the prefix is the target architecture and the name is a crate name.
 /// If an error occurs steps will be taken to ensure that no file is created.
-pub fn output_metadata(ecx: &ExtCtxt, prefix: &str, name: &str, err_map: &ErrorMap)
+pub fn output_metadata(ecx: &ExtCtxt<'_>, prefix: &str, name: &str, err_map: &ErrorMap)
     -> Result<(), Box<dyn Error>>
 {
     // Create the directory to place the file in.
diff --git a/src/libsyntax/diagnostics/plugin.rs b/src/libsyntax/diagnostics/plugin.rs
index fa6b825f2a2c2..21024eb41ef50 100644
--- a/src/libsyntax/diagnostics/plugin.rs
+++ b/src/libsyntax/diagnostics/plugin.rs
@@ -1,18 +1,19 @@
 use std::collections::BTreeMap;
 use std::env;
 
-use ast;
-use ast::{Ident, Name};
-use source_map;
+use crate::ast::{self, Ident, Name};
+use crate::source_map;
+use crate::ext::base::{ExtCtxt, MacEager, MacResult};
+use crate::ext::build::AstBuilder;
+use crate::parse::token;
+use crate::ptr::P;
+use crate::symbol::{keywords, Symbol};
+use crate::tokenstream::{TokenTree};
+
+use smallvec::smallvec;
 use syntax_pos::Span;
-use ext::base::{ExtCtxt, MacEager, MacResult};
-use ext::build::AstBuilder;
-use parse::token;
-use ptr::P;
-use symbol::{keywords, Symbol};
-use tokenstream::{TokenTree};
 
-use diagnostics::metadata::output_metadata;
+use crate::diagnostics::metadata::output_metadata;
 
 pub use errors::*;
 
@@ -28,7 +29,7 @@ pub struct ErrorInfo {
 /// Mapping from error codes to metadata.
 pub type ErrorMap = BTreeMap<Name, ErrorInfo>;
 
-pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
+pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt<'_>,
                                    span: Span,
                                    token_tree: &[TokenTree])
                                    -> Box<dyn MacResult+'cx> {
@@ -61,7 +62,7 @@ pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
     MacEager::expr(ecx.expr_tuple(span, Vec::new()))
 }
 
-pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
+pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt<'_>,
                                        span: Span,
                                        token_tree: &[TokenTree])
                                        -> Box<dyn MacResult+'cx> {
@@ -134,7 +135,7 @@ pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
 }
 
 #[allow(deprecated)]
-pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
+pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt<'_>,
                                           span: Span,
                                           token_tree: &[TokenTree])
                                           -> Box<dyn MacResult+'cx> {
diff --git a/src/libsyntax/early_buffered_lints.rs b/src/libsyntax/early_buffered_lints.rs
index cf9671a14b38d..29cb9cd7f30b5 100644
--- a/src/libsyntax/early_buffered_lints.rs
+++ b/src/libsyntax/early_buffered_lints.rs
@@ -3,7 +3,7 @@
 //! Since we cannot have a dependency on `librustc`, we implement some types here that are somewhat
 //! redundant. Later, these types can be converted to types for use by the rest of the compiler.
 
-use syntax::ast::NodeId;
+use crate::syntax::ast::NodeId;
 use syntax_pos::MultiSpan;
 
 /// Since we cannot import `LintId`s from `rustc::lint`, we define some Ids here which can later be
@@ -12,6 +12,8 @@ pub enum BufferedEarlyLintId {
     /// Usage of `?` as a macro separator is deprecated.
     QuestionMarkMacroSep,
     IllFormedAttributeInput,
+    /// Usage of a duplicate macro matcher binding name.
+    DuplicateMacroMatcherBindingName,
 }
 
 /// Stores buffered lint info which can later be passed to `librustc`.
diff --git a/src/libsyntax/entry.rs b/src/libsyntax/entry.rs
index 72a550a05d5da..09e26e29d86a8 100644
--- a/src/libsyntax/entry.rs
+++ b/src/libsyntax/entry.rs
@@ -1,5 +1,5 @@
-use attr;
-use ast::{Item, ItemKind};
+use crate::attr;
+use crate::ast::{Item, ItemKind};
 
 pub enum EntryPointType {
     None,
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 2793754e1033a..5980261593dbf 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -1,29 +1,29 @@
-pub use self::SyntaxExtension::*;
+pub use SyntaxExtension::*;
+
+use crate::ast::{self, Attribute, Name, PatKind, MetaItem};
+use crate::attr::HasAttrs;
+use crate::source_map::{SourceMap, Spanned, respan};
+use crate::edition::Edition;
+use crate::ext::expand::{self, AstFragment, Invocation};
+use crate::ext::hygiene::{self, Mark, SyntaxContext, Transparency};
+use crate::mut_visit::{self, MutVisitor};
+use crate::parse::{self, parser, DirectoryOwnership};
+use crate::parse::token;
+use crate::ptr::P;
+use crate::symbol::{keywords, Ident, Symbol};
+use crate::ThinVec;
+use crate::tokenstream::{self, TokenStream};
 
-use ast::{self, Attribute, Name, PatKind, MetaItem};
-use attr::HasAttrs;
-use source_map::{SourceMap, Spanned, respan};
-use syntax_pos::{Span, MultiSpan, DUMMY_SP};
-use edition::Edition;
 use errors::{DiagnosticBuilder, DiagnosticId};
-use ext::expand::{self, AstFragment, Invocation};
-use ext::hygiene::{self, Mark, SyntaxContext, Transparency};
-use fold::{self, Folder};
-use parse::{self, parser, DirectoryOwnership};
-use parse::token;
-use ptr::P;
-use smallvec::SmallVec;
-use symbol::{keywords, Ident, Symbol};
-use visit::Visitor;
-use ThinVec;
+use smallvec::{smallvec, SmallVec};
+use syntax_pos::{Span, MultiSpan, DUMMY_SP};
 
 use rustc_data_structures::fx::FxHashMap;
+use rustc_data_structures::sync::{self, Lrc};
 use std::iter;
 use std::path::PathBuf;
 use std::rc::Rc;
-use rustc_data_structures::sync::{self, Lrc};
 use std::default::Default;
-use tokenstream::{self, TokenStream};
 
 
 #[derive(Debug,Clone)]
@@ -48,15 +48,14 @@ impl HasAttrs for Annotatable {
         }
     }
 
-    fn map_attrs<F: FnOnce(Vec<Attribute>) -> Vec<Attribute>>(self, f: F) -> Self {
+    fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) {
         match self {
-            Annotatable::Item(item) => Annotatable::Item(item.map_attrs(f)),
-            Annotatable::TraitItem(trait_item) => Annotatable::TraitItem(trait_item.map_attrs(f)),
-            Annotatable::ImplItem(impl_item) => Annotatable::ImplItem(impl_item.map_attrs(f)),
-            Annotatable::ForeignItem(foreign_item) =>
-                Annotatable::ForeignItem(foreign_item.map_attrs(f)),
-            Annotatable::Stmt(stmt) => Annotatable::Stmt(stmt.map_attrs(f)),
-            Annotatable::Expr(expr) => Annotatable::Expr(expr.map_attrs(f)),
+            Annotatable::Item(item) => item.visit_attrs(f),
+            Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
+            Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
+            Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
+            Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
+            Annotatable::Expr(expr) => expr.visit_attrs(f),
         }
     }
 }
@@ -136,23 +135,12 @@ impl Annotatable {
             _ => false,
         }
     }
-
-    pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
-        match self {
-            Annotatable::Item(item) => visitor.visit_item(item),
-            Annotatable::TraitItem(trait_item) => visitor.visit_trait_item(trait_item),
-            Annotatable::ImplItem(impl_item) => visitor.visit_impl_item(impl_item),
-            Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
-            Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
-            Annotatable::Expr(expr) => visitor.visit_expr(expr),
-        }
-    }
 }
 
 // A more flexible ItemDecorator.
 pub trait MultiItemDecorator {
     fn expand(&self,
-              ecx: &mut ExtCtxt,
+              ecx: &mut ExtCtxt<'_>,
               sp: Span,
               meta_item: &ast::MetaItem,
               item: &Annotatable,
@@ -160,10 +148,10 @@ pub trait MultiItemDecorator {
 }
 
 impl<F> MultiItemDecorator for F
-    where F : Fn(&mut ExtCtxt, Span, &ast::MetaItem, &Annotatable, &mut dyn FnMut(Annotatable))
+    where F : Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, &Annotatable, &mut dyn FnMut(Annotatable))
 {
     fn expand(&self,
-              ecx: &mut ExtCtxt,
+              ecx: &mut ExtCtxt<'_>,
               sp: Span,
               meta_item: &ast::MetaItem,
               item: &Annotatable,
@@ -176,7 +164,7 @@ impl<F> MultiItemDecorator for F
 // FIXME Decorators should follow the same pattern too.
 pub trait MultiItemModifier {
     fn expand(&self,
-              ecx: &mut ExtCtxt,
+              ecx: &mut ExtCtxt<'_>,
               span: Span,
               meta_item: &ast::MetaItem,
               item: Annotatable)
@@ -184,11 +172,11 @@ pub trait MultiItemModifier {
 }
 
 impl<F, T> MultiItemModifier for F
-    where F: Fn(&mut ExtCtxt, Span, &ast::MetaItem, Annotatable) -> T,
+    where F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T,
           T: Into<Vec<Annotatable>>,
 {
     fn expand(&self,
-              ecx: &mut ExtCtxt,
+              ecx: &mut ExtCtxt<'_>,
               span: Span,
               meta_item: &ast::MetaItem,
               item: Annotatable)
@@ -205,7 +193,7 @@ impl Into<Vec<Annotatable>> for Annotatable {
 
 pub trait ProcMacro {
     fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt,
+                   ecx: &'cx mut ExtCtxt<'_>,
                    span: Span,
                    ts: TokenStream)
                    -> TokenStream;
@@ -215,7 +203,7 @@ impl<F> ProcMacro for F
     where F: Fn(TokenStream) -> TokenStream
 {
     fn expand<'cx>(&self,
-                   _ecx: &'cx mut ExtCtxt,
+                   _ecx: &'cx mut ExtCtxt<'_>,
                    _span: Span,
                    ts: TokenStream)
                    -> TokenStream {
@@ -226,7 +214,7 @@ impl<F> ProcMacro for F
 
 pub trait AttrProcMacro {
     fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt,
+                   ecx: &'cx mut ExtCtxt<'_>,
                    span: Span,
                    annotation: TokenStream,
                    annotated: TokenStream)
@@ -237,7 +225,7 @@ impl<F> AttrProcMacro for F
     where F: Fn(TokenStream, TokenStream) -> TokenStream
 {
     fn expand<'cx>(&self,
-                   _ecx: &'cx mut ExtCtxt,
+                   _ecx: &'cx mut ExtCtxt<'_>,
                    _span: Span,
                    annotation: TokenStream,
                    annotated: TokenStream)
@@ -251,7 +239,7 @@ impl<F> AttrProcMacro for F
 pub trait TTMacroExpander {
     fn expand<'cx>(
         &self,
-        ecx: &'cx mut ExtCtxt,
+        ecx: &'cx mut ExtCtxt<'_>,
         span: Span,
         input: TokenStream,
         def_span: Option<Span>,
@@ -259,47 +247,47 @@ pub trait TTMacroExpander {
 }
 
 pub type MacroExpanderFn =
-    for<'cx> fn(&'cx mut ExtCtxt, Span, &[tokenstream::TokenTree])
+    for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &[tokenstream::TokenTree])
                 -> Box<dyn MacResult+'cx>;
 
 impl<F> TTMacroExpander for F
-    where F: for<'cx> Fn(&'cx mut ExtCtxt, Span, &[tokenstream::TokenTree])
+    where F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, &[tokenstream::TokenTree])
     -> Box<dyn MacResult+'cx>
 {
     fn expand<'cx>(
         &self,
-        ecx: &'cx mut ExtCtxt,
+        ecx: &'cx mut ExtCtxt<'_>,
         span: Span,
         input: TokenStream,
         _def_span: Option<Span>,
     ) -> Box<dyn MacResult+'cx> {
         struct AvoidInterpolatedIdents;
 
-        impl Folder for AvoidInterpolatedIdents {
-            fn fold_tt(&mut self, tt: tokenstream::TokenTree) -> tokenstream::TokenTree {
-                if let tokenstream::TokenTree::Token(_, token::Interpolated(ref nt)) = tt {
+        impl MutVisitor for AvoidInterpolatedIdents {
+            fn visit_tt(&mut self, tt: &mut tokenstream::TokenTree) {
+                if let tokenstream::TokenTree::Token(_, token::Interpolated(nt)) = tt {
                     if let token::NtIdent(ident, is_raw) = nt.0 {
-                        return tokenstream::TokenTree::Token(ident.span,
-                                                             token::Ident(ident, is_raw));
+                        *tt = tokenstream::TokenTree::Token(ident.span,
+                                                            token::Ident(ident, is_raw));
                     }
                 }
-                fold::noop_fold_tt(tt, self)
+                mut_visit::noop_visit_tt(tt, self)
             }
 
-            fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
-                fold::noop_fold_mac(mac, self)
+            fn visit_mac(&mut self, mac: &mut ast::Mac) {
+                mut_visit::noop_visit_mac(mac, self)
             }
         }
 
         let input: Vec<_> =
-            input.trees().map(|tt| AvoidInterpolatedIdents.fold_tt(tt)).collect();
+            input.trees().map(|mut tt| { AvoidInterpolatedIdents.visit_tt(&mut tt); tt }).collect();
         (*self)(ecx, span, &input)
     }
 }
 
 pub trait IdentMacroExpander {
     fn expand<'cx>(&self,
-                   cx: &'cx mut ExtCtxt,
+                   cx: &'cx mut ExtCtxt<'_>,
                    sp: Span,
                    ident: ast::Ident,
                    token_tree: Vec<tokenstream::TokenTree>)
@@ -307,15 +295,15 @@ pub trait IdentMacroExpander {
 }
 
 pub type IdentMacroExpanderFn =
-    for<'cx> fn(&'cx mut ExtCtxt, Span, ast::Ident, Vec<tokenstream::TokenTree>)
+    for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident, Vec<tokenstream::TokenTree>)
                 -> Box<dyn MacResult+'cx>;
 
 impl<F> IdentMacroExpander for F
-    where F : for<'cx> Fn(&'cx mut ExtCtxt, Span, ast::Ident,
+    where F : for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident,
                           Vec<tokenstream::TokenTree>) -> Box<dyn MacResult+'cx>
 {
     fn expand<'cx>(&self,
-                   cx: &'cx mut ExtCtxt,
+                   cx: &'cx mut ExtCtxt<'_>,
                    sp: Span,
                    ident: ast::Ident,
                    token_tree: Vec<tokenstream::TokenTree>)
@@ -339,34 +327,34 @@ macro_rules! make_stmts_default {
 /// The result of a macro expansion. The return values of the various
 /// methods are spliced into the AST at the callsite of the macro.
 pub trait MacResult {
-    /// Create an expression.
+    /// Creates an expression.
     fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
         None
     }
-    /// Create zero or more items.
+    /// Creates zero or more items.
     fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
         None
     }
 
-    /// Create zero or more impl items.
+    /// Creates zero or more impl items.
     fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> {
         None
     }
 
-    /// Create zero or more trait items.
+    /// Creates zero or more trait items.
     fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> {
         None
     }
 
-    /// Create zero or more items in an `extern {}` block
+    /// Creates zero or more items in an `extern {}` block
     fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { None }
 
-    /// Create a pattern.
+    /// Creates a pattern.
     fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
         None
     }
 
-    /// Create zero or more statements.
+    /// Creates zero or more statements.
     ///
     /// By default this attempts to create an expression statement,
     /// returning None if that fails.
@@ -473,7 +461,7 @@ pub struct DummyResult {
 }
 
 impl DummyResult {
-    /// Create a default MacResult that can be anything.
+    /// Creates a default MacResult that can be anything.
     ///
     /// Use this as a return value after hitting any errors and
     /// calling `span_err`.
@@ -486,7 +474,7 @@ impl DummyResult {
         Box::new(DummyResult { expr_only: false, is_error: false, span })
     }
 
-    /// Create a default MacResult that can only be an expression.
+    /// Creates a default MacResult that can only be an expression.
     ///
     /// Use this for macros that must expand to an expression, so even
     /// if an error is encountered internally, the user will receive
@@ -580,7 +568,7 @@ impl MacResult for DummyResult {
 }
 
 pub type BuiltinDeriveFn =
-    for<'cx> fn(&'cx mut ExtCtxt, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
+    for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
 
 /// Represents different kinds of macro invocations that can be resolved.
 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
@@ -633,7 +621,8 @@ pub enum SyntaxExtension {
     /// A function-like procedural macro. TokenStream -> TokenStream.
     ProcMacro {
         expander: Box<dyn ProcMacro + sync::Sync + sync::Send>,
-        allow_internal_unstable: bool,
+        /// Whitelist of unstable features that are treated as stable inside this macro
+        allow_internal_unstable: Option<Lrc<[Symbol]>>,
         edition: Edition,
     },
 
@@ -650,8 +639,10 @@ pub enum SyntaxExtension {
         expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
         def_info: Option<(ast::NodeId, Span)>,
         /// Whether the contents of the macro can
-        /// directly use `#[unstable]` things (true == yes).
-        allow_internal_unstable: bool,
+        /// directly use `#[unstable]` things.
+        ///
+        /// Only allows things that require a feature gate in the given whitelist
+        allow_internal_unstable: Option<Lrc<[Symbol]>>,
         /// Whether the contents of the macro can use `unsafe`
         /// without triggering the `unsafe_code` lint.
         allow_internal_unsafe: bool,
@@ -666,8 +657,11 @@ pub enum SyntaxExtension {
 
     /// A function-like syntax extension that has an extra ident before
     /// the block.
-    ///
-    IdentTT(Box<dyn IdentMacroExpander + sync::Sync + sync::Send>, Option<Span>, bool),
+    IdentTT {
+        expander: Box<dyn IdentMacroExpander + sync::Sync + sync::Send>,
+        span: Option<Span>,
+        allow_internal_unstable: Option<Lrc<[Symbol]>>,
+    },
 
     /// An attribute-like procedural macro. TokenStream -> TokenStream.
     /// The input is the annotated item.
@@ -689,12 +683,12 @@ pub enum SyntaxExtension {
 }
 
 impl SyntaxExtension {
-    /// Return which kind of macro calls this syntax extension.
+    /// Returns which kind of macro calls this syntax extension.
     pub fn kind(&self) -> MacroKind {
         match *self {
             SyntaxExtension::DeclMacro { .. } |
             SyntaxExtension::NormalTT { .. } |
-            SyntaxExtension::IdentTT(..) |
+            SyntaxExtension::IdentTT { .. } |
             SyntaxExtension::ProcMacro { .. } =>
                 MacroKind::Bang,
             SyntaxExtension::NonMacroAttr { .. } |
@@ -728,7 +722,7 @@ impl SyntaxExtension {
             SyntaxExtension::ProcMacroDerive(.., edition) => edition,
             // Unstable legacy stuff
             SyntaxExtension::NonMacroAttr { .. } |
-            SyntaxExtension::IdentTT(..) |
+            SyntaxExtension::IdentTT { .. } |
             SyntaxExtension::MultiDecorator(..) |
             SyntaxExtension::MultiModifier(..) |
             SyntaxExtension::BuiltinDerive(..) => hygiene::default_edition(),
@@ -742,7 +736,7 @@ pub trait Resolver {
     fn next_node_id(&mut self) -> ast::NodeId;
     fn get_module_scope(&mut self, id: ast::NodeId) -> Mark;
 
-    fn resolve_dollar_crates(&mut self, annotatable: &Annotatable);
+    fn resolve_dollar_crates(&mut self, fragment: &AstFragment);
     fn visit_ast_fragment_with_placeholders(&mut self, mark: Mark, fragment: &AstFragment,
                                             derives: &[Mark]);
     fn add_builtin(&mut self, ident: ast::Ident, ext: Lrc<SyntaxExtension>);
@@ -776,7 +770,7 @@ impl Resolver for DummyResolver {
     fn next_node_id(&mut self) -> ast::NodeId { ast::DUMMY_NODE_ID }
     fn get_module_scope(&mut self, _id: ast::NodeId) -> Mark { Mark::root() }
 
-    fn resolve_dollar_crates(&mut self, _annotatable: &Annotatable) {}
+    fn resolve_dollar_crates(&mut self, _fragment: &AstFragment) {}
     fn visit_ast_fragment_with_placeholders(&mut self, _invoc: Mark, _fragment: &AstFragment,
                                             _derives: &[Mark]) {}
     fn add_builtin(&mut self, _ident: ast::Ident, _ext: Lrc<SyntaxExtension>) {}
@@ -847,8 +841,8 @@ impl<'a> ExtCtxt<'a> {
         expand::MacroExpander::new(self, false)
     }
 
-    /// Returns a `Folder` that deeply expands all macros and assigns all node ids in an AST node.
-    /// Once node ids are assigned, the node may not be expanded, removed, or otherwise modified.
+    /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
+    /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
     pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
         expand::MacroExpander::new(self, true)
     }
@@ -988,22 +982,19 @@ impl<'a> ExtCtxt<'a> {
     }
 }
 
-/// Extract a string literal from the macro expanded version of `expr`,
+/// Extracts a string literal from the macro expanded version of `expr`,
 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
-/// compilation on error, merely emits a non-fatal error and returns None.
+/// compilation on error, merely emits a non-fatal error and returns `None`.
 pub fn expr_to_spanned_string<'a>(
-    cx: &'a mut ExtCtxt,
-    expr: P<ast::Expr>,
+    cx: &'a mut ExtCtxt<'_>,
+    mut expr: P<ast::Expr>,
     err_msg: &str,
 ) -> Result<Spanned<(Symbol, ast::StrStyle)>, Option<DiagnosticBuilder<'a>>> {
     // Update `expr.span`'s ctxt now in case expr is an `include!` macro invocation.
-    let expr = expr.map(|mut expr| {
-        expr.span = expr.span.apply_mark(cx.current_expansion.mark);
-        expr
-    });
+    expr.span = expr.span.apply_mark(cx.current_expansion.mark);
 
     // we want to be able to handle e.g., `concat!("foo", "bar")`
-    let expr = cx.expander().fold_expr(expr);
+    cx.expander().visit_expr(&mut expr);
     Err(match expr.node {
         ast::ExprKind::Lit(ref l) => match l.node {
             ast::LitKind::Str(s, style) => return Ok(respan(expr.span, (s, style))),
@@ -1014,7 +1005,7 @@ pub fn expr_to_spanned_string<'a>(
     })
 }
 
-pub fn expr_to_string(cx: &mut ExtCtxt, expr: P<ast::Expr>, err_msg: &str)
+pub fn expr_to_string(cx: &mut ExtCtxt<'_>, expr: P<ast::Expr>, err_msg: &str)
                       -> Option<(Symbol, ast::StrStyle)> {
     expr_to_spanned_string(cx, expr, err_msg)
         .map_err(|err| err.map(|mut err| err.emit()))
@@ -1027,7 +1018,7 @@ pub fn expr_to_string(cx: &mut ExtCtxt, expr: P<ast::Expr>, err_msg: &str)
 /// compilation should call
 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
 /// done as rarely as possible).
-pub fn check_zero_tts(cx: &ExtCtxt,
+pub fn check_zero_tts(cx: &ExtCtxt<'_>,
                       sp: Span,
                       tts: &[tokenstream::TokenTree],
                       name: &str) {
@@ -1037,8 +1028,8 @@ pub fn check_zero_tts(cx: &ExtCtxt,
 }
 
 /// Interpreting `tts` as a comma-separated sequence of expressions,
-/// expect exactly one string literal, or emit an error and return None.
-pub fn get_single_str_from_tts(cx: &mut ExtCtxt,
+/// expect exactly one string literal, or emit an error and return `None`.
+pub fn get_single_str_from_tts(cx: &mut ExtCtxt<'_>,
                                sp: Span,
                                tts: &[tokenstream::TokenTree],
                                name: &str)
@@ -1059,15 +1050,17 @@ pub fn get_single_str_from_tts(cx: &mut ExtCtxt,
     })
 }
 
-/// Extract comma-separated expressions from `tts`. If there is a
-/// parsing error, emit a non-fatal error and return None.
-pub fn get_exprs_from_tts(cx: &mut ExtCtxt,
+/// Extracts comma-separated expressions from `tts`. If there is a
+/// parsing error, emit a non-fatal error and return `None`.
+pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>,
                           sp: Span,
                           tts: &[tokenstream::TokenTree]) -> Option<Vec<P<ast::Expr>>> {
     let mut p = cx.new_parser_from_tts(tts);
     let mut es = Vec::new();
     while p.token != token::Eof {
-        es.push(cx.expander().fold_expr(panictry!(p.parse_expr())));
+        let mut expr = panictry!(p.parse_expr());
+        cx.expander().visit_expr(&mut expr);
+        es.push(expr);
         if p.eat(&token::Comma) {
             continue;
         }
diff --git a/src/libsyntax/ext/build.rs b/src/libsyntax/ext/build.rs
index a8eec1a74dd2b..27b0cfb163077 100644
--- a/src/libsyntax/ext/build.rs
+++ b/src/libsyntax/ext/build.rs
@@ -1,18 +1,13 @@
+use crate::ast::{self, Ident, Generics, Expr, BlockCheckMode, UnOp, PatKind};
+use crate::attr;
+use crate::source_map::{dummy_spanned, respan, Spanned};
+use crate::ext::base::ExtCtxt;
+use crate::ptr::P;
+use crate::symbol::{Symbol, keywords};
+use crate::ThinVec;
+
 use rustc_target::spec::abi::Abi;
-use ast::{self, Ident, Generics, Expr, BlockCheckMode, UnOp, PatKind};
-use attr;
 use syntax_pos::{Pos, Span, DUMMY_SP};
-use source_map::{dummy_spanned, respan, Spanned};
-use ext::base::ExtCtxt;
-use ptr::P;
-use symbol::{Symbol, keywords};
-use ThinVec;
-
-// Transitional re-exports so qquote can find the paths it is looking for
-mod syntax {
-    pub use ext;
-    pub use parse;
-}
 
 pub trait AstBuilder {
     // paths
@@ -37,12 +32,14 @@ pub trait AstBuilder {
                 bindings: Vec<ast::TypeBinding>)
                 -> (ast::QSelf, ast::Path);
 
-    // types
+    // types and consts
     fn ty_mt(&self, ty: P<ast::Ty>, mutbl: ast::Mutability) -> ast::MutTy;
 
     fn ty(&self, span: Span, ty: ast::TyKind) -> P<ast::Ty>;
     fn ty_path(&self, path: ast::Path) -> P<ast::Ty>;
     fn ty_ident(&self, span: Span, idents: ast::Ident) -> P<ast::Ty>;
+    fn anon_const(&self, span: Span, expr: ast::ExprKind) -> ast::AnonConst;
+    fn const_ident(&self, span: Span, idents: ast::Ident) -> ast::AnonConst;
 
     fn ty_rptr(&self, span: Span,
                ty: P<ast::Ty>,
@@ -344,7 +341,7 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
 
     /// Constructs a qualified path.
     ///
-    /// Constructs a path like `<self_type as trait_path>::ident<'a, T, A=Bar>`.
+    /// Constructs a path like `<self_type as trait_path>::ident<'a, T, A = Bar>`.
     fn qpath_all(&self,
                  self_type: P<ast::Ty>,
                  trait_path: ast::Path,
@@ -393,6 +390,22 @@ impl<'a> AstBuilder for ExtCtxt<'a> {
         self.ty_path(self.path_ident(span, ident))
     }
 
+    fn anon_const(&self, span: Span, expr: ast::ExprKind) -> ast::AnonConst {
+        ast::AnonConst {
+            id: ast::DUMMY_NODE_ID,
+            value: P(ast::Expr {
+                id: ast::DUMMY_NODE_ID,
+                node: expr,
+                span,
+                attrs: ThinVec::new(),
+            })
+        }
+    }
+
+    fn const_ident(&self, span: Span, ident: ast::Ident) -> ast::AnonConst {
+        self.anon_const(span, ast::ExprKind::Path(None, self.path_ident(span, ident)))
+    }
+
     fn ty_rptr(&self,
                span: Span,
                ty: P<ast::Ty>,
diff --git a/src/libsyntax/ext/derive.rs b/src/libsyntax/ext/derive.rs
index 7ef09ce5fbd40..6df369133d01d 100644
--- a/src/libsyntax/ext/derive.rs
+++ b/src/libsyntax/ext/derive.rs
@@ -1,15 +1,16 @@
-use attr::HasAttrs;
-use ast;
-use source_map::{hygiene, ExpnInfo, ExpnFormat};
-use ext::base::ExtCtxt;
-use ext::build::AstBuilder;
-use parse::parser::PathStyle;
-use symbol::Symbol;
+use crate::attr::HasAttrs;
+use crate::ast;
+use crate::source_map::{hygiene, ExpnInfo, ExpnFormat};
+use crate::ext::base::ExtCtxt;
+use crate::ext::build::AstBuilder;
+use crate::parse::parser::PathStyle;
+use crate::symbol::Symbol;
+
 use syntax_pos::Span;
 
 use rustc_data_structures::fx::FxHashSet;
 
-pub fn collect_derives(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>) -> Vec<ast::Path> {
+pub fn collect_derives(cx: &mut ExtCtxt<'_>, attrs: &mut Vec<ast::Attribute>) -> Vec<ast::Path> {
     let mut result = Vec::new();
     attrs.retain(|attr| {
         if attr.path != "derive" {
@@ -40,7 +41,7 @@ pub fn collect_derives(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>) -> Vec
     result
 }
 
-pub fn add_derived_markers<T>(cx: &mut ExtCtxt, span: Span, traits: &[ast::Path], item: T) -> T
+pub fn add_derived_markers<T>(cx: &mut ExtCtxt<'_>, span: Span, traits: &[ast::Path], item: &mut T)
     where T: HasAttrs,
 {
     let (mut names, mut pretty_name) = (FxHashSet::default(), "derive(".to_owned());
@@ -57,14 +58,17 @@ pub fn add_derived_markers<T>(cx: &mut ExtCtxt, span: Span, traits: &[ast::Path]
         call_site: span,
         def_site: None,
         format: ExpnFormat::MacroAttribute(Symbol::intern(&pretty_name)),
-        allow_internal_unstable: true,
+        allow_internal_unstable: Some(vec![
+            Symbol::intern("rustc_attrs"),
+            Symbol::intern("structural_match"),
+        ].into()),
         allow_internal_unsafe: false,
         local_inner_macros: false,
         edition: hygiene::default_edition(),
     });
 
     let span = span.with_ctxt(cx.backtrace());
-    item.map_attrs(|mut attrs| {
+    item.visit_attrs(|attrs| {
         if names.contains(&Symbol::intern("Eq")) && names.contains(&Symbol::intern("PartialEq")) {
             let meta = cx.meta_word(span, Symbol::intern("structural_match"));
             attrs.push(cx.attribute(span, meta));
@@ -73,6 +77,5 @@ pub fn add_derived_markers<T>(cx: &mut ExtCtxt, span: Span, traits: &[ast::Path]
             let meta = cx.meta_word(span, Symbol::intern("rustc_copy_clone_marker"));
             attrs.push(cx.attribute(span, meta));
         }
-        attrs
-    })
+    });
 }
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9369e66cf83da..f50663f97853f 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1,32 +1,34 @@
-use ast::{self, Block, Ident, LitKind, NodeId, PatKind, Path};
-use ast::{MacStmtStyle, StmtKind, ItemKind};
-use attr::{self, HasAttrs};
-use source_map::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
-use config::StripUnconfigured;
+use crate::ast::{self, Block, Ident, LitKind, NodeId, PatKind, Path};
+use crate::ast::{MacStmtStyle, StmtKind, ItemKind};
+use crate::attr::{self, HasAttrs};
+use crate::source_map::{ExpnInfo, MacroBang, MacroAttribute, dummy_spanned, respan};
+use crate::config::StripUnconfigured;
+use crate::ext::base::*;
+use crate::ext::derive::{add_derived_markers, collect_derives};
+use crate::ext::hygiene::{self, Mark, SyntaxContext};
+use crate::ext::placeholders::{placeholder, PlaceholderExpander};
+use crate::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
+use crate::mut_visit::*;
+use crate::parse::{DirectoryOwnership, PResult, ParseSess};
+use crate::parse::token::{self, Token};
+use crate::parse::parser::Parser;
+use crate::ptr::P;
+use crate::symbol::Symbol;
+use crate::symbol::keywords;
+use crate::tokenstream::{TokenStream, TokenTree};
+use crate::visit::{self, Visitor};
+use crate::util::map_in_place::MapInPlace;
+
 use errors::{Applicability, FatalError};
-use ext::base::*;
-use ext::derive::{add_derived_markers, collect_derives};
-use ext::hygiene::{self, Mark, SyntaxContext};
-use ext::placeholders::{placeholder, PlaceholderExpander};
-use feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
-use fold;
-use fold::*;
-use parse::{DirectoryOwnership, PResult, ParseSess};
-use parse::token::{self, Token};
-use parse::parser::Parser;
-use ptr::P;
-use smallvec::SmallVec;
-use symbol::Symbol;
-use symbol::keywords;
+use smallvec::{smallvec, SmallVec};
 use syntax_pos::{Span, DUMMY_SP, FileName};
 use syntax_pos::hygiene::ExpnFormat;
-use tokenstream::{TokenStream, TokenTree};
-use visit::{self, Visitor};
 
 use rustc_data_structures::fx::FxHashMap;
 use std::fs;
 use std::io::ErrorKind;
 use std::{iter, mem};
+use std::ops::DerefMut;
 use std::rc::Rc;
 use std::path::PathBuf;
 
@@ -34,10 +36,8 @@ macro_rules! ast_fragments {
     (
         $($Kind:ident($AstTy:ty) {
             $kind_name:expr;
-            // FIXME: HACK: this should be `$(one ...)?` and `$(many ...)?` but `?` macro
-            // repetition was removed from 2015 edition in #51587 because of ambiguities.
-            $(one fn $fold_ast:ident; fn $visit_ast:ident;)*
-            $(many fn $fold_ast_elt:ident; fn $visit_ast_elt:ident;)*
+            $(one fn $mut_visit_ast:ident; fn $visit_ast:ident;)?
+            $(many fn $flat_map_ast_elt:ident; fn $visit_ast_elt:ident;)?
             fn $make_ast:ident;
         })*
     ) => {
@@ -87,16 +87,20 @@ macro_rules! ast_fragments {
                 }
             })*
 
-            pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
+            pub fn mut_visit_with<F: MutVisitor>(&mut self, vis: &mut F) {
                 match self {
-                    AstFragment::OptExpr(expr) =>
-                        AstFragment::OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
-                    $($(AstFragment::$Kind(ast) =>
-                        AstFragment::$Kind(folder.$fold_ast(ast)),)*)*
+                    AstFragment::OptExpr(opt_expr) => {
+                        visit_clobber(opt_expr, |opt_expr| {
+                            if let Some(expr) = opt_expr {
+                                vis.filter_map_expr(expr)
+                            } else {
+                                None
+                            }
+                        });
+                    }
+                    $($(AstFragment::$Kind(ast) => vis.$mut_visit_ast(ast),)*)*
                     $($(AstFragment::$Kind(ast) =>
-                        AstFragment::$Kind(ast.into_iter()
-                                              .flat_map(|ast| folder.$fold_ast_elt(ast))
-                                              .collect()),)*)*
+                        ast.flat_map_in_place(|ast| vis.$flat_map_ast_elt(ast)),)*)*
                 }
             }
 
@@ -112,20 +116,20 @@ macro_rules! ast_fragments {
             }
         }
 
-        impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
-            fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
+        impl<'a, 'b> MutVisitor for MacroExpander<'a, 'b> {
+            fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
                 self.expand_fragment(AstFragment::OptExpr(Some(expr))).make_opt_expr()
             }
-            $($(fn $fold_ast(&mut self, ast: $AstTy) -> $AstTy {
-                self.expand_fragment(AstFragment::$Kind(ast)).$make_ast()
+            $($(fn $mut_visit_ast(&mut self, ast: &mut $AstTy) {
+                visit_clobber(ast, |ast| self.expand_fragment(AstFragment::$Kind(ast)).$make_ast());
             })*)*
-            $($(fn $fold_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
+            $($(fn $flat_map_ast_elt(&mut self, ast_elt: <$AstTy as IntoIterator>::Item) -> $AstTy {
                 self.expand_fragment(AstFragment::$Kind(smallvec![ast_elt])).$make_ast()
             })*)*
         }
 
-        impl<'a> MacResult for ::ext::tt::macro_rules::ParserAnyMacro<'a> {
-            $(fn $make_ast(self: Box<::ext::tt::macro_rules::ParserAnyMacro<'a>>)
+        impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
+            $(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
                            -> Option<$AstTy> {
                 Some(self.make(AstFragmentKind::$Kind).$make_ast())
             })*
@@ -134,23 +138,23 @@ macro_rules! ast_fragments {
 }
 
 ast_fragments! {
-    Expr(P<ast::Expr>) { "expression"; one fn fold_expr; fn visit_expr; fn make_expr; }
-    Pat(P<ast::Pat>) { "pattern"; one fn fold_pat; fn visit_pat; fn make_pat; }
-    Ty(P<ast::Ty>) { "type"; one fn fold_ty; fn visit_ty; fn make_ty; }
+    Expr(P<ast::Expr>) { "expression"; one fn visit_expr; fn visit_expr; fn make_expr; }
+    Pat(P<ast::Pat>) { "pattern"; one fn visit_pat; fn visit_pat; fn make_pat; }
+    Ty(P<ast::Ty>) { "type"; one fn visit_ty; fn visit_ty; fn make_ty; }
     Stmts(SmallVec<[ast::Stmt; 1]>) {
-        "statement"; many fn fold_stmt; fn visit_stmt; fn make_stmts;
+        "statement"; many fn flat_map_stmt; fn visit_stmt; fn make_stmts;
     }
     Items(SmallVec<[P<ast::Item>; 1]>) {
-        "item"; many fn fold_item; fn visit_item; fn make_items;
+        "item"; many fn flat_map_item; fn visit_item; fn make_items;
     }
     TraitItems(SmallVec<[ast::TraitItem; 1]>) {
-        "trait item"; many fn fold_trait_item; fn visit_trait_item; fn make_trait_items;
+        "trait item"; many fn flat_map_trait_item; fn visit_trait_item; fn make_trait_items;
     }
     ImplItems(SmallVec<[ast::ImplItem; 1]>) {
-        "impl item"; many fn fold_impl_item; fn visit_impl_item; fn make_impl_items;
+        "impl item"; many fn flat_map_impl_item; fn visit_impl_item; fn make_impl_items;
     }
     ForeignItems(SmallVec<[ast::ForeignItem; 1]>) {
-        "foreign item"; many fn fold_foreign_item; fn visit_foreign_item; fn make_foreign_items;
+        "foreign item"; many fn flat_map_foreign_item; fn visit_foreign_item; fn make_foreign_items;
     }
 }
 
@@ -298,7 +302,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         self.cx.current_expansion.depth = 0;
 
         // Collect all macro invocations and replace them with placeholders.
-        let (fragment_with_placeholders, mut invocations)
+        let (mut fragment_with_placeholders, mut invocations)
             = self.collect_invocations(input_fragment, &[]);
 
         // Optimization: if we resolve all imports now,
@@ -361,7 +365,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                             let trait_list = traits.iter()
                                 .map(|t| t.to_string()).collect::<Vec<_>>();
                             let suggestion = format!("#[derive({})]", trait_list.join(", "));
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 span, "try an outer attribute", suggestion,
                                 // We don't 𝑘𝑛𝑜𝑤 that the following item is an ADT
                                 Applicability::MaybeIncorrect
@@ -370,10 +374,10 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         err.emit();
                     }
 
-                    let item = self.fully_configure(item)
-                        .map_attrs(|mut attrs| { attrs.retain(|a| a.path != "derive"); attrs });
-                    let item_with_markers =
-                        add_derived_markers(&mut self.cx, item.span(), &traits, item.clone());
+                    let mut item = self.fully_configure(item);
+                    item.visit_attrs(|attrs| attrs.retain(|a| a.path != "derive"));
+                    let mut item_with_markers = item.clone();
+                    add_derived_markers(&mut self.cx, item.span(), &traits, &mut item_with_markers);
                     let derives = derives.entry(invoc.expansion_data.mark).or_default();
 
                     derives.reserve(traits.len());
@@ -428,7 +432,8 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                          expanded_fragment, derives);
             }
         }
-        fragment_with_placeholders.fold_with(&mut placeholder_expander)
+        fragment_with_placeholders.mut_visit_with(&mut placeholder_expander);
+        fragment_with_placeholders
     }
 
     fn resolve_imports(&mut self) {
@@ -437,13 +442,16 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         }
     }
 
-    /// Collect all macro invocations reachable at this time in this AST fragment, and replace
+    /// Collects all macro invocations reachable at this time in this AST fragment, and replace
     /// them with "placeholders" - dummy macro invocations with specially crafted `NodeId`s.
     /// Then call into resolver that builds a skeleton ("reduced graph") of the fragment and
     /// prepares data for resolving paths of macro invocations.
-    fn collect_invocations(&mut self, fragment: AstFragment, derives: &[Mark])
+    fn collect_invocations(&mut self, mut fragment: AstFragment, derives: &[Mark])
                            -> (AstFragment, Vec<Invocation>) {
-        let (fragment_with_placeholders, invocations) = {
+        // Resolve `$crate`s in the fragment for pretty-printing.
+        self.cx.resolver.resolve_dollar_crates(&fragment);
+
+        let invocations = {
             let mut collector = InvocationCollector {
                 cfg: StripUnconfigured {
                     sess: self.cx.parse_sess,
@@ -453,16 +461,16 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 invocations: Vec::new(),
                 monotonic: self.monotonic,
             };
-            (fragment.fold_with(&mut collector), collector.invocations)
+            fragment.mut_visit_with(&mut collector);
+            collector.invocations
         };
 
         if self.monotonic {
             self.cx.resolver.visit_ast_fragment_with_placeholders(
-                self.cx.current_expansion.mark, &fragment_with_placeholders, derives
-            );
+                self.cx.current_expansion.mark, &fragment, derives);
         }
 
-        (fragment_with_placeholders, invocations)
+        (fragment, invocations)
     }
 
     fn fully_configure(&mut self, item: Annotatable) -> Annotatable {
@@ -474,24 +482,25 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         // we know that fold result vector will contain exactly one element
         match item {
             Annotatable::Item(item) => {
-                Annotatable::Item(cfg.fold_item(item).pop().unwrap())
+                Annotatable::Item(cfg.flat_map_item(item).pop().unwrap())
             }
             Annotatable::TraitItem(item) => {
-                Annotatable::TraitItem(item.map(|item| cfg.fold_trait_item(item).pop().unwrap()))
+                Annotatable::TraitItem(
+                    item.map(|item| cfg.flat_map_trait_item(item).pop().unwrap()))
             }
             Annotatable::ImplItem(item) => {
-                Annotatable::ImplItem(item.map(|item| cfg.fold_impl_item(item).pop().unwrap()))
+                Annotatable::ImplItem(item.map(|item| cfg.flat_map_impl_item(item).pop().unwrap()))
             }
             Annotatable::ForeignItem(item) => {
                 Annotatable::ForeignItem(
-                    item.map(|item| cfg.fold_foreign_item(item).pop().unwrap())
+                    item.map(|item| cfg.flat_map_foreign_item(item).pop().unwrap())
                 )
             }
             Annotatable::Stmt(stmt) => {
-                Annotatable::Stmt(stmt.map(|stmt| cfg.fold_stmt(stmt).pop().unwrap()))
+                Annotatable::Stmt(stmt.map(|stmt| cfg.flat_map_stmt(stmt).pop().unwrap()))
             }
-            Annotatable::Expr(expr) => {
-                Annotatable::Expr(cfg.fold_expr(expr))
+            Annotatable::Expr(mut expr) => {
+                Annotatable::Expr({ cfg.visit_expr(&mut expr); expr })
             }
         }
     }
@@ -533,7 +542,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                          invoc: Invocation,
                          ext: &SyntaxExtension)
                          -> Option<AstFragment> {
-        let (attr, item) = match invoc.kind {
+        let (attr, mut item) = match invoc.kind {
             InvocationKind::Attr { attr, item, .. } => (attr?, item),
             _ => unreachable!(),
         };
@@ -547,7 +556,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             call_site: attr.span,
             def_site: None,
             format: MacroAttribute(Symbol::intern(&attr.path.to_string())),
-            allow_internal_unstable: false,
+            allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: ext.edition(),
@@ -556,7 +565,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         match *ext {
             NonMacroAttr { .. } => {
                 attr::mark_known(&attr);
-                let item = item.map_attrs(|mut attrs| { attrs.push(attr); attrs });
+                item.visit_attrs(|attrs| attrs.push(attr));
                 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
             }
             MultiModifier(ref mac) => {
@@ -574,8 +583,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 Some(invoc.fragment_kind.expect_from_annotatables(items))
             }
             AttrProcMacro(ref mac, ..) => {
-                // Resolve `$crate`s in case we have to go though stringification.
-                self.cx.resolver.resolve_dollar_crates(&item);
                 self.gate_proc_macro_attr_item(attr.span, &item);
                 let item_tok = TokenTree::Token(DUMMY_SP, Token::interpolated(match item {
                     Annotatable::Item(item) => token::NtItem(item),
@@ -716,7 +723,8 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 // don't stability-check macros in the same crate
                 // (the only time this is null is for syntax extensions registered as macros)
                 if def_site_span.map_or(false, |def_span| !crate_span.contains(def_span))
-                    && !span.allows_unstable() && this.cx.ecfg.features.map_or(true, |feats| {
+                    && !span.allows_unstable(&feature.as_str())
+                    && this.cx.ecfg.features.map_or(true, |feats| {
                     // macro features will count as lib features
                     !feats.declared_lib_features.iter().any(|&(feat, _)| feat == feature)
                 }) {
@@ -748,7 +756,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         let opt_expanded = match *ext {
             DeclMacro { ref expander, def_info, edition, .. } => {
                 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
-                                                                    false, false, false, None,
+                                                                    None, false, false, None,
                                                                     edition) {
                     dummy_span
                 } else {
@@ -759,14 +767,14 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             NormalTT {
                 ref expander,
                 def_info,
-                allow_internal_unstable,
+                ref allow_internal_unstable,
                 allow_internal_unsafe,
                 local_inner_macros,
                 unstable_feature,
                 edition,
             } => {
                 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
-                                                                    allow_internal_unstable,
+                                                                    allow_internal_unstable.clone(),
                                                                     allow_internal_unsafe,
                                                                     local_inner_macros,
                                                                     unstable_feature,
@@ -782,7 +790,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 }
             }
 
-            IdentTT(ref expander, tt_span, allow_internal_unstable) => {
+            IdentTT { ref expander, span: tt_span, ref allow_internal_unstable } => {
                 if ident.name == keywords::Invalid.name() {
                     self.cx.span_err(path.span,
                                     &format!("macro {}! expects an ident argument", path));
@@ -793,7 +801,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         call_site: span,
                         def_site: tt_span,
                         format: macro_bang_format(path),
-                        allow_internal_unstable,
+                        allow_internal_unstable: allow_internal_unstable.clone(),
                         allow_internal_unsafe: false,
                         local_inner_macros: false,
                         edition: hygiene::default_edition(),
@@ -818,7 +826,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 kind.dummy(span)
             }
 
-            SyntaxExtension::ProcMacro { ref expander, allow_internal_unstable, edition } => {
+            SyntaxExtension::ProcMacro { ref expander, ref allow_internal_unstable, edition } => {
                 if ident.name != keywords::Invalid.name() {
                     let msg =
                         format!("macro {}! expects no ident argument, given '{}'", path, ident);
@@ -834,7 +842,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         def_site: None,
                         format: macro_bang_format(path),
                         // FIXME probably want to follow macro_rules macros here.
-                        allow_internal_unstable,
+                        allow_internal_unstable: allow_internal_unstable.clone(),
                         allow_internal_unsafe: false,
                         local_inner_macros: false,
                         edition,
@@ -909,7 +917,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             call_site: span,
             def_site: None,
             format: MacroAttribute(pretty_name),
-            allow_internal_unstable: false,
+            allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: ext.edition(),
@@ -917,8 +925,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
         match *ext {
             ProcMacroDerive(ref ext, ..) => {
-                // Resolve `$crate`s in case we have to go though stringification.
-                self.cx.resolver.resolve_dollar_crates(&item);
                 invoc.expansion_data.mark.set_expn_info(expn_info);
                 let span = span.with_ctxt(self.cx.backtrace());
                 let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
@@ -930,7 +936,12 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 Some(invoc.fragment_kind.expect_from_annotatables(items))
             }
             BuiltinDerive(func) => {
-                expn_info.allow_internal_unstable = true;
+                expn_info.allow_internal_unstable = Some(vec![
+                    Symbol::intern("rustc_attrs"),
+                    Symbol::intern("derive_clone_copy"),
+                    Symbol::intern("derive_eq"),
+                    Symbol::intern("libstd_sys_internals"), // RustcDeserialize and RustcSerialize
+                ].into());
                 invoc.expansion_data.mark.set_expn_info(expn_info);
                 let span = span.with_ctxt(self.cx.backtrace());
                 let mut items = Vec::new();
@@ -1043,7 +1054,7 @@ impl<'a> Parser<'a> {
             let semi_full_span = semi_span.to(self.sess.source_map().next_point(semi_span));
             match self.sess.source_map().span_to_snippet(semi_full_span) {
                 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         semi_span,
                         "you might be missing a semicolon here",
                         ";".to_owned(),
@@ -1115,34 +1126,32 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     }
 
     /// If `item` is an attr invocation, remove and return the macro attribute and derive traits.
-    fn classify_item<T>(&mut self, mut item: T)
-                        -> (Option<ast::Attribute>, Vec<Path>, T, /* after_derive */ bool)
+    fn classify_item<T>(&mut self, item: &mut T)
+                        -> (Option<ast::Attribute>, Vec<Path>, /* after_derive */ bool)
         where T: HasAttrs,
     {
         let (mut attr, mut traits, mut after_derive) = (None, Vec::new(), false);
 
-        item = item.map_attrs(|mut attrs| {
+        item.visit_attrs(|mut attrs| {
             attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
             traits = collect_derives(&mut self.cx, &mut attrs);
-            attrs
         });
 
-        (attr, traits, item, after_derive)
+        (attr, traits, after_derive)
     }
 
-    /// Alternative of `classify_item()` that ignores `#[derive]` so invocations fallthrough
+    /// Alternative to `classify_item()` that ignores `#[derive]` so invocations fallthrough
     /// to the unused-attributes lint (making it an error on statements and expressions
     /// is a breaking change)
-    fn classify_nonitem<T: HasAttrs>(&mut self, mut item: T)
-                                     -> (Option<ast::Attribute>, T, /* after_derive */ bool) {
+    fn classify_nonitem<T: HasAttrs>(&mut self, nonitem: &mut T)
+                                     -> (Option<ast::Attribute>, /* after_derive */ bool) {
         let (mut attr, mut after_derive) = (None, false);
 
-        item = item.map_attrs(|mut attrs| {
+        nonitem.visit_attrs(|mut attrs| {
             attr = self.find_attr_invoc(&mut attrs, &mut after_derive);
-            attrs
         });
 
-        (attr, item, after_derive)
+        (attr, after_derive)
     }
 
     fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
@@ -1175,14 +1184,14 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
     }
 }
 
-impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
-    fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
-        let expr = self.cfg.configure_expr(expr);
-        expr.map(|mut expr| {
-            expr.node = self.cfg.configure_expr_kind(expr.node);
+impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
+    fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
+        self.cfg.configure_expr(expr);
+        visit_clobber(expr.deref_mut(), |mut expr| {
+            self.cfg.configure_expr_kind(&mut expr.node);
 
             // ignore derives so they remain unused
-            let (attr, expr, after_derive) = self.classify_nonitem(expr);
+            let (attr, after_derive) = self.classify_nonitem(&mut expr);
 
             if attr.is_some() {
                 // Collect the invoc regardless of whether or not attributes are permitted here
@@ -1191,7 +1200,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
 
                 // AstFragmentKind::Expr requires the macro to emit an expression.
                 return self.collect_attr(attr, vec![], Annotatable::Expr(P(expr)),
-                                         AstFragmentKind::Expr, after_derive)
+                                          AstFragmentKind::Expr, after_derive)
                     .make_expr()
                     .into_inner()
             }
@@ -1202,18 +1211,19 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                     .make_expr()
                     .into_inner()
             } else {
-                noop_fold_expr(expr, self)
+                noop_visit_expr(&mut expr, self);
+                expr
             }
-        })
+        });
     }
 
-    fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
+    fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
         let expr = configure!(self, expr);
         expr.filter_map(|mut expr| {
-            expr.node = self.cfg.configure_expr_kind(expr.node);
+            self.cfg.configure_expr_kind(&mut expr.node);
 
             // Ignore derives so they remain unused.
-            let (attr, expr, after_derive) = self.classify_nonitem(expr);
+            let (attr, after_derive) = self.classify_nonitem(&mut expr);
 
             if attr.is_some() {
                 attr.as_ref().map(|a| self.cfg.maybe_emit_expr_attr_err(a));
@@ -1230,47 +1240,45 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                     .make_opt_expr()
                     .map(|expr| expr.into_inner())
             } else {
-                Some(noop_fold_expr(expr, self))
+                Some({ noop_visit_expr(&mut expr, self); expr })
             }
         })
     }
 
-    fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
-        let pat = self.cfg.configure_pat(pat);
+    fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
+        self.cfg.configure_pat(pat);
         match pat.node {
             PatKind::Mac(_) => {}
-            _ => return noop_fold_pat(pat, self),
+            _ => return noop_visit_pat(pat, self),
         }
 
-        pat.and_then(|pat| match pat.node {
-            PatKind::Mac(mac) => self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
-            _ => unreachable!(),
-        })
+        visit_clobber(pat, |mut pat| {
+            match mem::replace(&mut pat.node, PatKind::Wild) {
+                PatKind::Mac(mac) =>
+                    self.collect_bang(mac, pat.span, AstFragmentKind::Pat).make_pat(),
+                _ => unreachable!(),
+            }
+        });
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
-        let mut stmt = match self.cfg.configure_stmt(stmt) {
-            Some(stmt) => stmt,
-            None => return SmallVec::new(),
-        };
+    fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
+        let mut stmt = configure!(self, stmt);
 
         // we'll expand attributes on expressions separately
         if !stmt.is_expr() {
-            let (attr, derives, stmt_, after_derive) = if stmt.is_item() {
-                self.classify_item(stmt)
+            let (attr, derives, after_derive) = if stmt.is_item() {
+                self.classify_item(&mut stmt)
             } else {
                 // ignore derives on non-item statements so it falls through
                 // to the unused-attributes lint
-                let (attr, stmt, after_derive) = self.classify_nonitem(stmt);
-                (attr, vec![], stmt, after_derive)
+                let (attr, after_derive) = self.classify_nonitem(&mut stmt);
+                (attr, vec![], after_derive)
             };
 
             if attr.is_some() || !derives.is_empty() {
-                return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt_)),
+                return self.collect_attr(attr, derives, Annotatable::Stmt(P(stmt)),
                                          AstFragmentKind::Stmts, after_derive).make_stmts();
             }
-
-            stmt = stmt_;
         }
 
         if let StmtKind::Mac(mac) = stmt.node {
@@ -1292,24 +1300,23 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
 
         // The placeholder expander gives ids to statements, so we avoid folding the id here.
         let ast::Stmt { id, node, span } = stmt;
-        noop_fold_stmt_kind(node, self).into_iter().map(|node| {
+        noop_flat_map_stmt_kind(node, self).into_iter().map(|node| {
             ast::Stmt { id, node, span }
         }).collect()
 
     }
 
-    fn fold_block(&mut self, block: P<Block>) -> P<Block> {
+    fn visit_block(&mut self, block: &mut P<Block>) {
         let old_directory_ownership = self.cx.current_expansion.directory_ownership;
         self.cx.current_expansion.directory_ownership = DirectoryOwnership::UnownedViaBlock;
-        let result = noop_fold_block(block, self);
+        noop_visit_block(block, self);
         self.cx.current_expansion.directory_ownership = old_directory_ownership;
-        result
     }
 
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
-        let item = configure!(self, item);
+    fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
+        let mut item = configure!(self, item);
 
-        let (attr, traits, item, after_derive) = self.classify_item(item);
+        let (attr, traits, after_derive) = self.classify_item(&mut item);
         if attr.is_some() || !traits.is_empty() {
             return self.collect_attr(attr, traits, Annotatable::Item(item),
                                      AstFragmentKind::Items, after_derive).make_items();
@@ -1331,7 +1338,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
             }
             ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
                 if item.ident == keywords::Invalid.ident() {
-                    return noop_fold_item(item, self);
+                    return noop_flat_map_item(item, self);
                 }
 
                 let orig_directory_ownership = self.cx.current_expansion.directory_ownership;
@@ -1371,20 +1378,20 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
 
                 let orig_module =
                     mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
-                let result = noop_fold_item(item, self);
+                let result = noop_flat_map_item(item, self);
                 self.cx.current_expansion.module = orig_module;
                 self.cx.current_expansion.directory_ownership = orig_directory_ownership;
                 result
             }
 
-            _ => noop_fold_item(item, self),
+            _ => noop_flat_map_item(item, self),
         }
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
-        let item = configure!(self, item);
+    fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
+        let mut item = configure!(self, item);
 
-        let (attr, traits, item, after_derive) = self.classify_item(item);
+        let (attr, traits, after_derive) = self.classify_item(&mut item);
         if attr.is_some() || !traits.is_empty() {
             return self.collect_attr(attr, traits, Annotatable::TraitItem(P(item)),
                                      AstFragmentKind::TraitItems, after_derive).make_trait_items()
@@ -1396,14 +1403,14 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                 self.check_attributes(&attrs);
                 self.collect_bang(mac, span, AstFragmentKind::TraitItems).make_trait_items()
             }
-            _ => fold::noop_fold_trait_item(item, self),
+            _ => noop_flat_map_trait_item(item, self),
         }
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
-        let item = configure!(self, item);
+    fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
+        let mut item = configure!(self, item);
 
-        let (attr, traits, item, after_derive) = self.classify_item(item);
+        let (attr, traits, after_derive) = self.classify_item(&mut item);
         if attr.is_some() || !traits.is_empty() {
             return self.collect_attr(attr, traits, Annotatable::ImplItem(P(item)),
                                      AstFragmentKind::ImplItems, after_derive).make_impl_items();
@@ -1415,30 +1422,34 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                 self.check_attributes(&attrs);
                 self.collect_bang(mac, span, AstFragmentKind::ImplItems).make_impl_items()
             }
-            _ => fold::noop_fold_impl_item(item, self),
+            _ => noop_flat_map_impl_item(item, self),
         }
     }
 
-    fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
-        let ty = match ty.node {
-            ast::TyKind::Mac(_) => ty.into_inner(),
-            _ => return fold::noop_fold_ty(ty, self),
+    fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
+        match ty.node {
+            ast::TyKind::Mac(_) => {}
+            _ => return noop_visit_ty(ty, self),
         };
 
-        match ty.node {
-            ast::TyKind::Mac(mac) => self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
-            _ => unreachable!(),
-        }
+        visit_clobber(ty, |mut ty| {
+            match mem::replace(&mut ty.node, ast::TyKind::Err) {
+                ast::TyKind::Mac(mac) =>
+                    self.collect_bang(mac, ty.span, AstFragmentKind::Ty).make_ty(),
+                _ => unreachable!(),
+            }
+        });
     }
 
-    fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
-        noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
+    fn visit_foreign_mod(&mut self, foreign_mod: &mut ast::ForeignMod) {
+        self.cfg.configure_foreign_mod(foreign_mod);
+        noop_visit_foreign_mod(foreign_mod, self);
     }
 
-    fn fold_foreign_item(&mut self, foreign_item: ast::ForeignItem)
+    fn flat_map_foreign_item(&mut self, mut foreign_item: ast::ForeignItem)
         -> SmallVec<[ast::ForeignItem; 1]>
     {
-        let (attr, traits, foreign_item, after_derive) = self.classify_item(foreign_item);
+        let (attr, traits, after_derive) = self.classify_item(&mut foreign_item);
 
         if attr.is_some() || !traits.is_empty() {
             return self.collect_attr(attr, traits, Annotatable::ForeignItem(P(foreign_item)),
@@ -1452,38 +1463,41 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                 .make_foreign_items();
         }
 
-        noop_fold_foreign_item(foreign_item, self)
+        noop_flat_map_foreign_item(foreign_item, self)
     }
 
-    fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
+    fn visit_item_kind(&mut self, item: &mut ast::ItemKind) {
         match item {
-            ast::ItemKind::MacroDef(..) => item,
-            _ => noop_fold_item_kind(self.cfg.configure_item_kind(item), self),
+            ast::ItemKind::MacroDef(..) => {}
+            _ => {
+                self.cfg.configure_item_kind(item);
+                noop_visit_item_kind(item, self);
+            }
         }
     }
 
-    fn fold_generic_param(&mut self, param: ast::GenericParam) -> ast::GenericParam {
+    fn visit_generic_param(&mut self, param: &mut ast::GenericParam) {
         self.cfg.disallow_cfg_on_generic_param(&param);
-        noop_fold_generic_param(param, self)
+        noop_visit_generic_param(param, self)
     }
 
-    fn fold_attribute(&mut self, at: ast::Attribute) -> Option<ast::Attribute> {
+    fn visit_attribute(&mut self, at: &mut ast::Attribute) {
         // turn `#[doc(include="filename")]` attributes into `#[doc(include(file="filename",
         // contents="file contents")]` attributes
         if !at.check_name("doc") {
-            return noop_fold_attribute(at, self);
+            return noop_visit_attribute(at, self);
         }
 
         if let Some(list) = at.meta_item_list() {
             if !list.iter().any(|it| it.check_name("include")) {
-                return noop_fold_attribute(at, self);
+                return noop_visit_attribute(at, self);
             }
 
             let mut items = vec![];
 
-            for it in list {
+            for mut it in list {
                 if !it.check_name("include") {
-                    items.push(noop_fold_meta_list_item(it, self));
+                    items.push({ noop_visit_meta_list_item(&mut it, self); it });
                     continue;
                 }
 
@@ -1492,7 +1506,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                     self.check_attribute(&at);
                     if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
                         // avoid loading the file if they haven't enabled the feature
-                        return noop_fold_attribute(at, self);
+                        return noop_visit_attribute(at, self);
                     }
 
                     let filename = self.cx.root_path.join(file.to_string());
@@ -1574,7 +1588,7 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
                         _ => (String::from("<path>"), Applicability::HasPlaceholders),
                     };
 
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         it.span,
                         "provide a file path with `=`",
                         format!("include = \"{}\"", path),
@@ -1587,22 +1601,18 @@ impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
 
             let meta = attr::mk_list_item(DUMMY_SP, Ident::from_str("doc"), items);
             match at.style {
-                ast::AttrStyle::Inner =>
-                    Some(attr::mk_spanned_attr_inner(at.span, at.id, meta)),
-                ast::AttrStyle::Outer =>
-                    Some(attr::mk_spanned_attr_outer(at.span, at.id, meta)),
+                ast::AttrStyle::Inner => *at = attr::mk_spanned_attr_inner(at.span, at.id, meta),
+                ast::AttrStyle::Outer => *at = attr::mk_spanned_attr_outer(at.span, at.id, meta),
             }
         } else {
-            noop_fold_attribute(at, self)
+            noop_visit_attribute(at, self)
         }
     }
 
-    fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
+    fn visit_id(&mut self, id: &mut ast::NodeId) {
         if self.monotonic {
-            assert_eq!(id, ast::DUMMY_NODE_ID);
-            self.cx.resolver.next_node_id()
-        } else {
-            id
+            debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
+            *id = self.cx.resolver.next_node_id()
         }
     }
 }
@@ -1667,12 +1677,12 @@ impl<'feat> ExpansionConfig<'feat> {
 #[derive(Debug)]
 pub struct Marker(pub Mark);
 
-impl Folder for Marker {
-    fn new_span(&mut self, span: Span) -> Span {
-        span.apply_mark(self.0)
+impl MutVisitor for Marker {
+    fn visit_span(&mut self, span: &mut Span) {
+        *span = span.apply_mark(self.0)
     }
 
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
-        noop_fold_mac(mac, self)
+    fn visit_mac(&mut self, mac: &mut ast::Mac) {
+        noop_visit_mac(mac, self)
     }
 }
diff --git a/src/libsyntax/ext/placeholders.rs b/src/libsyntax/ext/placeholders.rs
index 3b0402d910a85..3e60dd81a3bc8 100644
--- a/src/libsyntax/ext/placeholders.rs
+++ b/src/libsyntax/ext/placeholders.rs
@@ -1,15 +1,15 @@
-use ast::{self, NodeId};
-use source_map::{DUMMY_SP, dummy_spanned};
-use ext::base::ExtCtxt;
-use ext::expand::{AstFragment, AstFragmentKind};
-use ext::hygiene::Mark;
-use tokenstream::TokenStream;
-use fold::*;
-use ptr::P;
-use smallvec::SmallVec;
-use symbol::keywords;
-use ThinVec;
-use util::move_map::MoveMap;
+use crate::ast::{self, NodeId};
+use crate::source_map::{DUMMY_SP, dummy_spanned};
+use crate::ext::base::ExtCtxt;
+use crate::ext::expand::{AstFragment, AstFragmentKind};
+use crate::ext::hygiene::Mark;
+use crate::tokenstream::TokenStream;
+use crate::mut_visit::*;
+use crate::ptr::P;
+use crate::symbol::keywords;
+use crate::ThinVec;
+
+use smallvec::{smallvec, SmallVec};
 
 use rustc_data_structures::fx::FxHashMap;
 
@@ -85,8 +85,8 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
         }
     }
 
-    pub fn add(&mut self, id: ast::NodeId, fragment: AstFragment, derives: Vec<Mark>) {
-        let mut fragment = fragment.fold_with(self);
+    pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment, derives: Vec<Mark>) {
+        fragment.mut_visit_with(self);
         if let AstFragment::Items(mut items) = fragment {
             for derive in derives {
                 match self.remove(NodeId::placeholder_from_mark(derive)) {
@@ -104,56 +104,56 @@ impl<'a, 'b> PlaceholderExpander<'a, 'b> {
     }
 }
 
-impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
-    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
+impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
+    fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
         match item.node {
             ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
             ast::ItemKind::MacroDef(_) => return smallvec![item],
             _ => {}
         }
 
-        noop_fold_item(item, self)
+        noop_flat_map_item(item, self)
     }
 
-    fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
+    fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
         match item.node {
             ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
-            _ => noop_fold_trait_item(item, self),
+            _ => noop_flat_map_trait_item(item, self),
         }
     }
 
-    fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
+    fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
         match item.node {
             ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
-            _ => noop_fold_impl_item(item, self),
+            _ => noop_flat_map_impl_item(item, self),
         }
     }
 
-    fn fold_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
+    fn flat_map_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
         match item.node {
             ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
-            _ => noop_fold_foreign_item(item, self),
+            _ => noop_flat_map_foreign_item(item, self),
         }
     }
 
-    fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
+    fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
         match expr.node {
-            ast::ExprKind::Mac(_) => self.remove(expr.id).make_expr(),
-            _ => expr.map(|expr| noop_fold_expr(expr, self)),
+            ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
+            _ => noop_visit_expr(expr, self),
         }
     }
 
-    fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
+    fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
         match expr.node {
             ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
-            _ => noop_fold_opt_expr(expr, self),
+            _ => noop_filter_map_expr(expr, self),
         }
     }
 
-    fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
+    fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
         let (style, mut stmts) = match stmt.node {
             ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
-            _ => return noop_fold_stmt(stmt, self),
+            _ => return noop_flat_map_stmt(stmt, self),
         };
 
         if style == ast::MacStmtStyle::Semicolon {
@@ -165,49 +165,40 @@ impl<'a, 'b> Folder for PlaceholderExpander<'a, 'b> {
         stmts
     }
 
-    fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
+    fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
         match pat.node {
-            ast::PatKind::Mac(_) => self.remove(pat.id).make_pat(),
-            _ => noop_fold_pat(pat, self),
+            ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
+            _ => noop_visit_pat(pat, self),
         }
     }
 
-    fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
+    fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
         match ty.node {
-            ast::TyKind::Mac(_) => self.remove(ty.id).make_ty(),
-            _ => noop_fold_ty(ty, self),
+            ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
+            _ => noop_visit_ty(ty, self),
         }
     }
 
-    fn fold_block(&mut self, block: P<ast::Block>) -> P<ast::Block> {
-        noop_fold_block(block, self).map(|mut block| {
-            let mut remaining_stmts = block.stmts.len();
+    fn visit_block(&mut self, block: &mut P<ast::Block>) {
+        noop_visit_block(block, self);
 
-            block.stmts = block.stmts.move_flat_map(|mut stmt| {
-                remaining_stmts -= 1;
-
-                if self.monotonic {
-                    assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
-                    stmt.id = self.cx.resolver.next_node_id();
-                }
-
-                Some(stmt)
-            });
-
-            block
-        })
+        for stmt in block.stmts.iter_mut() {
+            if self.monotonic {
+                assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
+                stmt.id = self.cx.resolver.next_node_id();
+            }
+        }
     }
 
-    fn fold_mod(&mut self, module: ast::Mod) -> ast::Mod {
-        let mut module = noop_fold_mod(module, self);
-        module.items = module.items.move_flat_map(|item| match item.node {
-            ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => None, // remove macro definitions
-            _ => Some(item),
+    fn visit_mod(&mut self, module: &mut ast::Mod) {
+        noop_visit_mod(module, self);
+        module.items.retain(|item| match item.node {
+            ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
+            _ => true,
         });
-        module
     }
 
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
-        mac
+    fn visit_mac(&mut self, _mac: &mut ast::Mac) {
+        // Do nothing.
     }
 }
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
deleted file mode 100644
index c3124144009ab..0000000000000
--- a/src/libsyntax/ext/quote.rs
+++ /dev/null
@@ -1,892 +0,0 @@
-use ast::{self, Arg, Arm, Block, Expr, Item, Pat, Stmt, Ty};
-use source_map::respan;
-use syntax_pos::{Span, DUMMY_SP};
-use ext::base::ExtCtxt;
-use ext::base;
-use ext::build::AstBuilder;
-use parse::parser::{Parser, PathStyle};
-use parse::token;
-use ptr::P;
-use tokenstream::{DelimSpan, TokenStream, TokenTree};
-
-/// Quasiquoting works via token trees.
-///
-/// This is registered as a set of expression syntax extension called quote!
-/// that lifts its argument token-tree to an AST representing the
-/// construction of the same token tree, with `token::SubstNt` interpreted
-/// as antiquotes (splices).
-
-pub mod rt {
-    use ast;
-    use source_map::Spanned;
-    use ext::base::ExtCtxt;
-    use parse::{self, classify};
-    use parse::token::{self, Token};
-    use ptr::P;
-    use symbol::Symbol;
-    use ThinVec;
-
-    use tokenstream::{DelimSpan, TokenTree, TokenStream};
-
-    pub use parse::new_parser_from_tts;
-    pub use syntax_pos::{BytePos, Span, DUMMY_SP, FileName};
-    pub use source_map::{dummy_spanned};
-
-    pub trait ToTokens {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree>;
-    }
-
-    impl ToTokens for TokenTree {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            vec![self.clone()]
-        }
-    }
-
-    impl<T: ToTokens> ToTokens for Vec<T> {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            self.iter().flat_map(|t| t.to_tokens(cx)).collect()
-        }
-    }
-
-    impl<T: ToTokens> ToTokens for Spanned<T> {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            // FIXME: use the span?
-            self.node.to_tokens(cx)
-        }
-    }
-
-    impl<T: ToTokens> ToTokens for Option<T> {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            match *self {
-                Some(ref t) => t.to_tokens(cx),
-                None => Vec::new(),
-            }
-        }
-    }
-
-    impl ToTokens for ast::Ident {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            vec![TokenTree::Token(self.span, Token::from_ast_ident(*self))]
-        }
-    }
-
-    impl ToTokens for ast::Path {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtPath(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Ty {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtTy(P(self.clone()));
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Block {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtBlock(P(self.clone()));
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Generics {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtGenerics(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::WhereClause {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtWhereClause(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for P<ast::Item> {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtItem(self.clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::ImplItem {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtImplItem(self.clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for P<ast::ImplItem> {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtImplItem((**self).clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::TraitItem {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtTraitItem(self.clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Stmt {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtStmt(self.clone());
-            let mut tts = vec![TokenTree::Token(self.span, Token::interpolated(nt))];
-
-            // Some statements require a trailing semicolon.
-            if classify::stmt_ends_with_semi(&self.node) {
-                tts.push(TokenTree::Token(self.span, token::Semi));
-            }
-
-            tts
-        }
-    }
-
-    impl ToTokens for P<ast::Expr> {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtExpr(self.clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for P<ast::Pat> {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtPat(self.clone());
-            vec![TokenTree::Token(self.span, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Arm {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtArm(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Arg {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtArg(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for P<ast::Block> {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtBlock(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Lifetime {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            vec![TokenTree::Token(self.ident.span, token::Lifetime(self.ident))]
-        }
-    }
-
-    macro_rules! impl_to_tokens_slice {
-        ($t: ty, $sep: expr) => {
-            impl ToTokens for [$t] {
-                fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-                    let mut v = vec![];
-                    for (i, x) in self.iter().enumerate() {
-                        if i > 0 {
-                            v.extend_from_slice(&$sep);
-                        }
-                        v.extend(x.to_tokens(cx));
-                    }
-                    v
-                }
-            }
-        };
-    }
-
-    impl_to_tokens_slice! { ast::Ty, [TokenTree::Token(DUMMY_SP, token::Comma)] }
-    impl_to_tokens_slice! { P<ast::Item>, [] }
-    impl_to_tokens_slice! { ast::Arg, [TokenTree::Token(DUMMY_SP, token::Comma)] }
-
-    impl ToTokens for ast::MetaItem {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let nt = token::NtMeta(self.clone());
-            vec![TokenTree::Token(DUMMY_SP, Token::interpolated(nt))]
-        }
-    }
-
-    impl ToTokens for ast::Attribute {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            let mut r = vec![];
-            // FIXME: The spans could be better
-            r.push(TokenTree::Token(self.span, token::Pound));
-            if self.style == ast::AttrStyle::Inner {
-                r.push(TokenTree::Token(self.span, token::Not));
-            }
-            let mut inner = Vec::new();
-            for (i, segment) in self.path.segments.iter().enumerate() {
-                if i > 0 {
-                    inner.push(TokenTree::Token(self.span, token::Colon).into());
-                }
-                inner.push(TokenTree::Token(
-                    self.span, token::Token::from_ast_ident(segment.ident)
-                ).into());
-            }
-            self.tokens.clone().append_to_tree_and_joint_vec(&mut inner);
-
-            let delim_span = DelimSpan::from_single(self.span);
-            r.push(TokenTree::Delimited(
-                delim_span, token::Bracket, TokenStream::new(inner).into()
-            ));
-            r
-        }
-    }
-
-    impl ToTokens for str {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            let lit = ast::LitKind::Str(Symbol::intern(self), ast::StrStyle::Cooked);
-            dummy_spanned(lit).to_tokens(cx)
-        }
-    }
-
-    impl ToTokens for () {
-        fn to_tokens(&self, _cx: &ExtCtxt) -> Vec<TokenTree> {
-            vec![
-                TokenTree::Delimited(DelimSpan::dummy(), token::Paren, TokenStream::empty().into())
-            ]
-        }
-    }
-
-    impl ToTokens for ast::Lit {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            // FIXME: This is wrong
-            P(ast::Expr {
-                id: ast::DUMMY_NODE_ID,
-                node: ast::ExprKind::Lit(self.clone()),
-                span: DUMMY_SP,
-                attrs: ThinVec::new(),
-            }).to_tokens(cx)
-        }
-    }
-
-    impl ToTokens for bool {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            dummy_spanned(ast::LitKind::Bool(*self)).to_tokens(cx)
-        }
-    }
-
-    impl ToTokens for char {
-        fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-            dummy_spanned(ast::LitKind::Char(*self)).to_tokens(cx)
-        }
-    }
-
-    macro_rules! impl_to_tokens_int {
-        (signed, $t:ty, $tag:expr) => (
-            impl ToTokens for $t {
-                fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-                    let val = if *self < 0 {
-                        -self
-                    } else {
-                        *self
-                    };
-                    let lit = ast::LitKind::Int(val as u128, ast::LitIntType::Signed($tag));
-                    let lit = P(ast::Expr {
-                        id: ast::DUMMY_NODE_ID,
-                        node: ast::ExprKind::Lit(dummy_spanned(lit)),
-                        span: DUMMY_SP,
-                        attrs: ThinVec::new(),
-                    });
-                    if *self >= 0 {
-                        return lit.to_tokens(cx);
-                    }
-                    P(ast::Expr {
-                        id: ast::DUMMY_NODE_ID,
-                        node: ast::ExprKind::Unary(ast::UnOp::Neg, lit),
-                        span: DUMMY_SP,
-                        attrs: ThinVec::new(),
-                    }).to_tokens(cx)
-                }
-            }
-        );
-        (unsigned, $t:ty, $tag:expr) => (
-            impl ToTokens for $t {
-                fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-                    let lit = ast::LitKind::Int(*self as u128, ast::LitIntType::Unsigned($tag));
-                    dummy_spanned(lit).to_tokens(cx)
-                }
-            }
-        );
-    }
-
-    impl_to_tokens_int! { signed, isize, ast::IntTy::Isize }
-    impl_to_tokens_int! { signed, i8,  ast::IntTy::I8 }
-    impl_to_tokens_int! { signed, i16, ast::IntTy::I16 }
-    impl_to_tokens_int! { signed, i32, ast::IntTy::I32 }
-    impl_to_tokens_int! { signed, i64, ast::IntTy::I64 }
-
-    impl_to_tokens_int! { unsigned, usize, ast::UintTy::Usize }
-    impl_to_tokens_int! { unsigned, u8,   ast::UintTy::U8 }
-    impl_to_tokens_int! { unsigned, u16,  ast::UintTy::U16 }
-    impl_to_tokens_int! { unsigned, u32,  ast::UintTy::U32 }
-    impl_to_tokens_int! { unsigned, u64,  ast::UintTy::U64 }
-
-    pub trait ExtParseUtils {
-        fn parse_item(&self, s: String) -> P<ast::Item>;
-        fn parse_expr(&self, s: String) -> P<ast::Expr>;
-        fn parse_stmt(&self, s: String) -> ast::Stmt;
-        fn parse_tts(&self, s: String) -> Vec<TokenTree>;
-    }
-
-    impl<'a> ExtParseUtils for ExtCtxt<'a> {
-        fn parse_item(&self, s: String) -> P<ast::Item> {
-            panictry!(parse::parse_item_from_source_str(
-                FileName::quote_expansion_source_code(&s),
-                s,
-                self.parse_sess())).expect("parse error")
-        }
-
-        fn parse_stmt(&self, s: String) -> ast::Stmt {
-            panictry!(parse::parse_stmt_from_source_str(
-                FileName::quote_expansion_source_code(&s),
-                s,
-                self.parse_sess())).expect("parse error")
-        }
-
-        fn parse_expr(&self, s: String) -> P<ast::Expr> {
-            panictry!(parse::parse_expr_from_source_str(
-                FileName::quote_expansion_source_code(&s),
-                s,
-                self.parse_sess()))
-        }
-
-        fn parse_tts(&self, s: String) -> Vec<TokenTree> {
-            let source_name = FileName::quote_expansion_source_code(&s);
-            parse::parse_stream_from_source_str(source_name, s, self.parse_sess(), None)
-                .into_trees().collect()
-        }
-    }
-}
-
-// Replaces `Token::OpenDelim .. Token::CloseDelim` with `TokenTree::Delimited(..)`.
-pub fn unflatten(tts: Vec<TokenTree>) -> Vec<TokenTree> {
-    let mut results = Vec::new();
-    let mut result = Vec::new();
-    let mut open_span = DUMMY_SP;
-    for tree in tts {
-        match tree {
-            TokenTree::Token(span, token::OpenDelim(..)) => {
-                open_span = span;
-                results.push(::std::mem::replace(&mut result, Vec::new()));
-            }
-            TokenTree::Token(span, token::CloseDelim(delim)) => {
-                let delim_span = DelimSpan::from_pair(open_span, span);
-                let tree = TokenTree::Delimited(
-                    delim_span,
-                    delim,
-                    result.into_iter().map(TokenStream::from).collect::<TokenStream>().into(),
-                );
-                result = results.pop().unwrap();
-                result.push(tree);
-            }
-            tree => result.push(tree),
-        }
-    }
-    result
-}
-
-// These panicking parsing functions are used by the quote_*!() syntax extensions,
-// but shouldn't be used otherwise.
-pub fn parse_expr_panic(parser: &mut Parser) -> P<Expr> {
-    panictry!(parser.parse_expr())
-}
-
-pub fn parse_item_panic(parser: &mut Parser) -> Option<P<Item>> {
-    panictry!(parser.parse_item())
-}
-
-pub fn parse_pat_panic(parser: &mut Parser) -> P<Pat> {
-    panictry!(parser.parse_pat(None))
-}
-
-pub fn parse_arm_panic(parser: &mut Parser) -> Arm {
-    panictry!(parser.parse_arm())
-}
-
-pub fn parse_ty_panic(parser: &mut Parser) -> P<Ty> {
-    panictry!(parser.parse_ty())
-}
-
-pub fn parse_stmt_panic(parser: &mut Parser) -> Option<Stmt> {
-    panictry!(parser.parse_stmt())
-}
-
-pub fn parse_attribute_panic(parser: &mut Parser, permit_inner: bool) -> ast::Attribute {
-    panictry!(parser.parse_attribute(permit_inner))
-}
-
-pub fn parse_arg_panic(parser: &mut Parser) -> Arg {
-    panictry!(parser.parse_arg())
-}
-
-pub fn parse_block_panic(parser: &mut Parser) -> P<Block> {
-    panictry!(parser.parse_block())
-}
-
-pub fn parse_meta_item_panic(parser: &mut Parser) -> ast::MetaItem {
-    panictry!(parser.parse_meta_item())
-}
-
-pub fn parse_path_panic(parser: &mut Parser, mode: PathStyle) -> ast::Path {
-    panictry!(parser.parse_path(mode))
-}
-
-pub fn expand_quote_tokens<'cx>(cx: &'cx mut ExtCtxt,
-                                sp: Span,
-                                tts: &[TokenTree])
-                                -> Box<dyn base::MacResult+'cx> {
-    let (cx_expr, expr) = expand_tts(cx, sp, tts);
-    let expanded = expand_wrapper(cx, sp, cx_expr, expr, &[&["syntax", "ext", "quote", "rt"]]);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_expr<'cx>(cx: &'cx mut ExtCtxt,
-                              sp: Span,
-                              tts: &[TokenTree])
-                              -> Box<dyn base::MacResult+'cx> {
-    let expanded = expand_parse_call(cx, sp, "parse_expr_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_item<'cx>(cx: &'cx mut ExtCtxt,
-                              sp: Span,
-                              tts: &[TokenTree])
-                              -> Box<dyn base::MacResult+'cx> {
-    let expanded = expand_parse_call(cx, sp, "parse_item_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_pat<'cx>(cx: &'cx mut ExtCtxt,
-                             sp: Span,
-                             tts: &[TokenTree])
-                             -> Box<dyn base::MacResult+'cx> {
-    let expanded = expand_parse_call(cx, sp, "parse_pat_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_arm(cx: &mut ExtCtxt,
-                        sp: Span,
-                        tts: &[TokenTree])
-                        -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_arm_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_ty(cx: &mut ExtCtxt,
-                       sp: Span,
-                       tts: &[TokenTree])
-                       -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_ty_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_stmt(cx: &mut ExtCtxt,
-                         sp: Span,
-                         tts: &[TokenTree])
-                         -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_stmt_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_attr(cx: &mut ExtCtxt,
-                         sp: Span,
-                         tts: &[TokenTree])
-                         -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_attribute_panic",
-                                    vec![cx.expr_bool(sp, true)], tts);
-
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_arg(cx: &mut ExtCtxt,
-                        sp: Span,
-                        tts: &[TokenTree])
-                        -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_arg_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_block(cx: &mut ExtCtxt,
-                        sp: Span,
-                        tts: &[TokenTree])
-                        -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_block_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_meta_item(cx: &mut ExtCtxt,
-                        sp: Span,
-                        tts: &[TokenTree])
-                        -> Box<dyn base::MacResult+'static> {
-    let expanded = expand_parse_call(cx, sp, "parse_meta_item_panic", vec![], tts);
-    base::MacEager::expr(expanded)
-}
-
-pub fn expand_quote_path(cx: &mut ExtCtxt,
-                        sp: Span,
-                        tts: &[TokenTree])
-                        -> Box<dyn base::MacResult+'static> {
-    let mode = mk_parser_path(cx, sp, &["PathStyle", "Type"]);
-    let expanded = expand_parse_call(cx, sp, "parse_path_panic", vec![mode], tts);
-    base::MacEager::expr(expanded)
-}
-
-fn ids_ext(strs: Vec<String>) -> Vec<ast::Ident> {
-    strs.iter().map(|s| ast::Ident::from_str(s)).collect()
-}
-
-fn id_ext(s: &str) -> ast::Ident {
-    ast::Ident::from_str(s)
-}
-
-// Lift an ident to the expr that evaluates to that ident.
-fn mk_ident(cx: &ExtCtxt, sp: Span, ident: ast::Ident) -> P<ast::Expr> {
-    let e_str = cx.expr_str(sp, ident.name);
-    cx.expr_method_call(sp,
-                        cx.expr_ident(sp, id_ext("ext_cx")),
-                        id_ext("ident_of"),
-                        vec![e_str])
-}
-
-// Lift a name to the expr that evaluates to that name
-fn mk_name(cx: &ExtCtxt, sp: Span, ident: ast::Ident) -> P<ast::Expr> {
-    let e_str = cx.expr_str(sp, ident.name);
-    cx.expr_method_call(sp,
-                        cx.expr_ident(sp, id_ext("ext_cx")),
-                        id_ext("name_of"),
-                        vec![e_str])
-}
-
-fn mk_tt_path(cx: &ExtCtxt, sp: Span, name: &str) -> P<ast::Expr> {
-    let idents = vec![id_ext("syntax"), id_ext("tokenstream"), id_ext("TokenTree"), id_ext(name)];
-    cx.expr_path(cx.path_global(sp, idents))
-}
-
-fn mk_token_path(cx: &ExtCtxt, sp: Span, name: &str) -> P<ast::Expr> {
-    let idents = vec![id_ext("syntax"), id_ext("parse"), id_ext("token"), id_ext(name)];
-    cx.expr_path(cx.path_global(sp, idents))
-}
-
-fn mk_parser_path(cx: &ExtCtxt, sp: Span, names: &[&str]) -> P<ast::Expr> {
-    let mut idents = vec![id_ext("syntax"), id_ext("parse"), id_ext("parser")];
-    idents.extend(names.iter().cloned().map(id_ext));
-    cx.expr_path(cx.path_global(sp, idents))
-}
-
-fn mk_binop(cx: &ExtCtxt, sp: Span, bop: token::BinOpToken) -> P<ast::Expr> {
-    let name = match bop {
-        token::Plus     => "Plus",
-        token::Minus    => "Minus",
-        token::Star     => "Star",
-        token::Slash    => "Slash",
-        token::Percent  => "Percent",
-        token::Caret    => "Caret",
-        token::And      => "And",
-        token::Or       => "Or",
-        token::Shl      => "Shl",
-        token::Shr      => "Shr"
-    };
-    mk_token_path(cx, sp, name)
-}
-
-fn mk_delim(cx: &ExtCtxt, sp: Span, delim: token::DelimToken) -> P<ast::Expr> {
-    let name = match delim {
-        token::Paren   => "Paren",
-        token::Bracket => "Bracket",
-        token::Brace   => "Brace",
-        token::NoDelim => "NoDelim",
-    };
-    mk_token_path(cx, sp, name)
-}
-
-#[allow(non_upper_case_globals)]
-fn expr_mk_token(cx: &ExtCtxt, sp: Span, tok: &token::Token) -> P<ast::Expr> {
-    macro_rules! mk_lit {
-        ($name: expr, $suffix: expr, $content: expr $(, $count: expr)*) => {{
-            let name = mk_name(cx, sp, ast::Ident::with_empty_ctxt($content));
-            let inner = cx.expr_call(sp, mk_token_path(cx, sp, $name), vec![
-                name $(, cx.expr_u16(sp, $count))*
-            ]);
-            let suffix = match $suffix {
-                Some(name) => cx.expr_some(sp, mk_name(cx, sp, ast::Ident::with_empty_ctxt(name))),
-                None => cx.expr_none(sp)
-            };
-            cx.expr_call(sp, mk_token_path(cx, sp, "Literal"), vec![inner, suffix])
-        }}
-    }
-
-    let name = match *tok {
-        token::BinOp(binop) => {
-            return cx.expr_call(sp, mk_token_path(cx, sp, "BinOp"), vec![mk_binop(cx, sp, binop)]);
-        }
-        token::BinOpEq(binop) => {
-            return cx.expr_call(sp, mk_token_path(cx, sp, "BinOpEq"),
-                                vec![mk_binop(cx, sp, binop)]);
-        }
-
-        token::OpenDelim(delim) => {
-            return cx.expr_call(sp, mk_token_path(cx, sp, "OpenDelim"),
-                                vec![mk_delim(cx, sp, delim)]);
-        }
-        token::CloseDelim(delim) => {
-            return cx.expr_call(sp, mk_token_path(cx, sp, "CloseDelim"),
-                                vec![mk_delim(cx, sp, delim)]);
-        }
-
-        token::Literal(token::Byte(i), suf) => return mk_lit!("Byte", suf, i),
-        token::Literal(token::Char(i), suf) => return mk_lit!("Char", suf, i),
-        token::Literal(token::Integer(i), suf) => return mk_lit!("Integer", suf, i),
-        token::Literal(token::Float(i), suf) => return mk_lit!("Float", suf, i),
-        token::Literal(token::Str_(i), suf) => return mk_lit!("Str_", suf, i),
-        token::Literal(token::StrRaw(i, n), suf) => return mk_lit!("StrRaw", suf, i, n),
-        token::Literal(token::ByteStr(i), suf) => return mk_lit!("ByteStr", suf, i),
-        token::Literal(token::ByteStrRaw(i, n), suf) => return mk_lit!("ByteStrRaw", suf, i, n),
-
-        token::Ident(ident, is_raw) => {
-            return cx.expr_call(sp,
-                                mk_token_path(cx, sp, "Ident"),
-                                vec![mk_ident(cx, sp, ident), cx.expr_bool(sp, is_raw)]);
-        }
-
-        token::Lifetime(ident) => {
-            return cx.expr_call(sp,
-                                mk_token_path(cx, sp, "Lifetime"),
-                                vec![mk_ident(cx, sp, ident)]);
-        }
-
-        token::DocComment(ident) => {
-            return cx.expr_call(sp,
-                                mk_token_path(cx, sp, "DocComment"),
-                                vec![mk_name(cx, sp, ast::Ident::with_empty_ctxt(ident))]);
-        }
-
-        token::Interpolated(_) => {
-            cx.span_err(sp, "quote! with interpolated token");
-            // Use dummy name.
-            "Interpolated"
-        }
-
-        token::Eq           => "Eq",
-        token::Lt           => "Lt",
-        token::Le           => "Le",
-        token::EqEq         => "EqEq",
-        token::Ne           => "Ne",
-        token::Ge           => "Ge",
-        token::Gt           => "Gt",
-        token::AndAnd       => "AndAnd",
-        token::OrOr         => "OrOr",
-        token::Not          => "Not",
-        token::Tilde        => "Tilde",
-        token::At           => "At",
-        token::Dot          => "Dot",
-        token::DotDot       => "DotDot",
-        token::DotDotDot    => "DotDotDot",
-        token::DotDotEq     => "DotDotEq",
-        token::Comma        => "Comma",
-        token::Semi         => "Semi",
-        token::Colon        => "Colon",
-        token::ModSep       => "ModSep",
-        token::RArrow       => "RArrow",
-        token::LArrow       => "LArrow",
-        token::FatArrow     => "FatArrow",
-        token::Pound        => "Pound",
-        token::Dollar       => "Dollar",
-        token::Question     => "Question",
-        token::SingleQuote  => "SingleQuote",
-        token::Eof          => "Eof",
-
-        token::Whitespace | token::Comment | token::Shebang(_) => {
-            panic!("unhandled token in quote!");
-        }
-    };
-    mk_token_path(cx, sp, name)
-}
-
-fn statements_mk_tt(cx: &ExtCtxt, tt: &TokenTree, quoted: bool) -> Vec<ast::Stmt> {
-    match *tt {
-        TokenTree::Token(sp, token::Ident(ident, _)) if quoted => {
-            // tt.extend($ident.to_tokens(ext_cx))
-
-            let e_to_toks =
-                cx.expr_method_call(sp,
-                                    cx.expr_ident(sp, ident),
-                                    id_ext("to_tokens"),
-                                    vec![cx.expr_ident(sp, id_ext("ext_cx"))]);
-            let e_to_toks =
-                cx.expr_method_call(sp, e_to_toks, id_ext("into_iter"), vec![]);
-
-            let e_push =
-                cx.expr_method_call(sp,
-                                    cx.expr_ident(sp, id_ext("tt")),
-                                    id_ext("extend"),
-                                    vec![e_to_toks]);
-
-            vec![cx.stmt_expr(e_push)]
-        }
-        TokenTree::Token(sp, ref tok) => {
-            let e_sp = cx.expr_ident(sp, id_ext("_sp"));
-            let e_tok = cx.expr_call(sp,
-                                     mk_tt_path(cx, sp, "Token"),
-                                     vec![e_sp, expr_mk_token(cx, sp, tok)]);
-            let e_push =
-                cx.expr_method_call(sp,
-                                    cx.expr_ident(sp, id_ext("tt")),
-                                    id_ext("push"),
-                                    vec![e_tok]);
-            vec![cx.stmt_expr(e_push)]
-        },
-        TokenTree::Delimited(span, delim, ref tts) => {
-            let mut stmts = statements_mk_tt(cx, &TokenTree::open_tt(span.open, delim), false);
-            stmts.extend(statements_mk_tts(cx, tts.stream()));
-            stmts.extend(statements_mk_tt(cx, &TokenTree::close_tt(span.close, delim), false));
-            stmts
-        }
-    }
-}
-
-fn parse_arguments_to_quote(cx: &ExtCtxt, tts: &[TokenTree])
-                            -> (P<ast::Expr>, Vec<TokenTree>) {
-    let mut p = cx.new_parser_from_tts(tts);
-
-    let cx_expr = panictry!(p.parse_expr());
-    if !p.eat(&token::Comma) {
-        let _ = p.diagnostic().fatal("expected token `,`");
-    }
-
-    let tts = panictry!(p.parse_all_token_trees());
-    p.abort_if_errors();
-
-    (cx_expr, tts)
-}
-
-fn mk_stmts_let(cx: &ExtCtxt, sp: Span) -> Vec<ast::Stmt> {
-    // We also bind a single value, sp, to ext_cx.call_site()
-    //
-    // This causes every span in a token-tree quote to be attributed to the
-    // call site of the extension using the quote. We can't really do much
-    // better since the source of the quote may well be in a library that
-    // was not even parsed by this compilation run, that the user has no
-    // source code for (eg. in libsyntax, which they're just _using_).
-    //
-    // The old quasiquoter had an elaborate mechanism for denoting input
-    // file locations from which quotes originated; unfortunately this
-    // relied on feeding the source string of the quote back into the
-    // compiler (which we don't really want to do) and, in any case, only
-    // pushed the problem a very small step further back: an error
-    // resulting from a parse of the resulting quote is still attributed to
-    // the site the string literal occurred, which was in a source file
-    // _other_ than the one the user has control over. For example, an
-    // error in a quote from the protocol compiler, invoked in user code
-    // using macro_rules! for example, will be attributed to the macro_rules.rs
-    // file in libsyntax, which the user might not even have source to (unless
-    // they happen to have a compiler on hand). Over all, the phase distinction
-    // just makes quotes "hard to attribute". Possibly this could be fixed
-    // by recreating some of the original qq machinery in the tt regime
-    // (pushing fake SourceFiles onto the parser to account for original sites
-    // of quotes, for example) but at this point it seems not likely to be
-    // worth the hassle.
-
-    let e_sp = cx.expr_method_call(sp,
-                                   cx.expr_ident(sp, id_ext("ext_cx")),
-                                   id_ext("call_site"),
-                                   Vec::new());
-
-    let stmt_let_sp = cx.stmt_let(sp, false,
-                                  id_ext("_sp"),
-                                  e_sp);
-
-    let stmt_let_tt = cx.stmt_let(sp, true, id_ext("tt"), cx.expr_vec_ng(sp));
-
-    vec![stmt_let_sp, stmt_let_tt]
-}
-
-fn statements_mk_tts(cx: &ExtCtxt, tts: TokenStream) -> Vec<ast::Stmt> {
-    let mut ss = Vec::new();
-    let mut quoted = false;
-    for tt in tts.into_trees() {
-        quoted = match tt {
-            TokenTree::Token(_, token::Dollar) if !quoted => true,
-            _ => {
-                ss.extend(statements_mk_tt(cx, &tt, quoted));
-                false
-            }
-        }
-    }
-    ss
-}
-
-fn expand_tts(cx: &ExtCtxt, sp: Span, tts: &[TokenTree]) -> (P<ast::Expr>, P<ast::Expr>) {
-    let (cx_expr, tts) = parse_arguments_to_quote(cx, tts);
-
-    let mut vector = mk_stmts_let(cx, sp);
-    vector.extend(statements_mk_tts(cx, tts.iter().cloned().collect()));
-    vector.push(cx.stmt_expr(cx.expr_ident(sp, id_ext("tt"))));
-    let block = cx.expr_block(cx.block(sp, vector));
-    let unflatten = vec![id_ext("syntax"), id_ext("ext"), id_ext("quote"), id_ext("unflatten")];
-
-    (cx_expr, cx.expr_call_global(sp, unflatten, vec![block]))
-}
-
-fn expand_wrapper(cx: &ExtCtxt,
-                  sp: Span,
-                  cx_expr: P<ast::Expr>,
-                  expr: P<ast::Expr>,
-                  imports: &[&[&str]]) -> P<ast::Expr> {
-    // Explicitly borrow to avoid moving from the invoker (#16992)
-    let cx_expr_borrow = cx.expr_addr_of(sp, cx.expr_deref(sp, cx_expr));
-    let stmt_let_ext_cx = cx.stmt_let(sp, false, id_ext("ext_cx"), cx_expr_borrow);
-
-    let mut stmts = imports.iter().map(|path| {
-        // make item: `use ...;`
-        let path = path.iter().map(|s| s.to_string()).collect();
-        let use_item = cx.item_use_glob(
-            sp,
-            respan(sp.shrink_to_lo(), ast::VisibilityKind::Inherited),
-            ids_ext(path),
-        );
-        cx.stmt_item(sp, use_item)
-    }).chain(Some(stmt_let_ext_cx)).collect::<Vec<_>>();
-    stmts.push(cx.stmt_expr(expr));
-
-    cx.expr_block(cx.block(sp, stmts))
-}
-
-fn expand_parse_call(cx: &ExtCtxt,
-                     sp: Span,
-                     parse_method: &str,
-                     arg_exprs: Vec<P<ast::Expr>> ,
-                     tts: &[TokenTree]) -> P<ast::Expr> {
-    let (cx_expr, tts_expr) = expand_tts(cx, sp, tts);
-
-    let parse_sess_call = || cx.expr_method_call(
-        sp, cx.expr_ident(sp, id_ext("ext_cx")),
-        id_ext("parse_sess"), Vec::new());
-
-    let new_parser_call =
-        cx.expr_call(sp,
-                     cx.expr_ident(sp, id_ext("new_parser_from_tts")),
-                     vec![parse_sess_call(), tts_expr]);
-
-    let path = vec![id_ext("syntax"), id_ext("ext"), id_ext("quote"), id_ext(parse_method)];
-    let mut args = vec![cx.expr_mut_addr_of(sp, new_parser_call)];
-    args.extend(arg_exprs);
-    let expr = cx.expr_call_global(sp, path, args);
-
-    if parse_method == "parse_attribute" {
-        expand_wrapper(cx, sp, cx_expr, expr, &[&["syntax", "ext", "quote", "rt"],
-                                                &["syntax", "parse", "attr"]])
-    } else {
-        expand_wrapper(cx, sp, cx_expr, expr, &[&["syntax", "ext", "quote", "rt"]])
-    }
-}
diff --git a/src/libsyntax/ext/source_util.rs b/src/libsyntax/ext/source_util.rs
index e63042a420824..549de1628eb55 100644
--- a/src/libsyntax/ext/source_util.rs
+++ b/src/libsyntax/ext/source_util.rs
@@ -1,15 +1,14 @@
-use ast;
-use syntax_pos::{self, Pos, Span, FileName};
-use ext::base::*;
-use ext::base;
-use ext::build::AstBuilder;
-use parse::{token, DirectoryOwnership};
-use parse;
-use print::pprust;
-use ptr::P;
+use crate::ast;
+use crate::ext::base::{self, *};
+use crate::ext::build::AstBuilder;
+use crate::parse::{self, token, DirectoryOwnership};
+use crate::print::pprust;
+use crate::ptr::P;
+use crate::symbol::Symbol;
+use crate::tokenstream;
+
 use smallvec::SmallVec;
-use symbol::Symbol;
-use tokenstream;
+use syntax_pos::{self, Pos, Span, FileName};
 
 use std::fs;
 use std::io::ErrorKind;
@@ -21,7 +20,7 @@ use rustc_data_structures::sync::Lrc;
 // a given file into the current one.
 
 /// line!(): expands to the current line number
-pub fn expand_line(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_line(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                    -> Box<dyn base::MacResult+'static> {
     base::check_zero_tts(cx, sp, tts, "line!");
 
@@ -32,7 +31,7 @@ pub fn expand_line(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
 }
 
 /* column!(): expands to the current column number */
-pub fn expand_column(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_column(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                   -> Box<dyn base::MacResult+'static> {
     base::check_zero_tts(cx, sp, tts, "column!");
 
@@ -43,9 +42,9 @@ pub fn expand_column(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
 }
 
 /* __rust_unstable_column!(): expands to the current column number */
-pub fn expand_column_gated(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_column_gated(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                   -> Box<dyn base::MacResult+'static> {
-    if sp.allows_unstable() {
+    if sp.allows_unstable("__rust_unstable_column") {
         expand_column(cx, sp, tts)
     } else {
         cx.span_fatal(sp, "the __rust_unstable_column macro is unstable");
@@ -55,7 +54,7 @@ pub fn expand_column_gated(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::Token
 /// file!(): expands to the current filename */
 /// The source_file (`loc.file`) contains a bunch more information we could spit
 /// out if we wanted.
-pub fn expand_file(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_file(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                    -> Box<dyn base::MacResult+'static> {
     base::check_zero_tts(cx, sp, tts, "file!");
 
@@ -64,13 +63,13 @@ pub fn expand_file(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
     base::MacEager::expr(cx.expr_str(topmost, Symbol::intern(&loc.file.name.to_string())))
 }
 
-pub fn expand_stringify(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_stringify(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                         -> Box<dyn base::MacResult+'static> {
     let s = pprust::tts_to_string(tts);
     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&s)))
 }
 
-pub fn expand_mod(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_mod(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                   -> Box<dyn base::MacResult+'static> {
     base::check_zero_tts(cx, sp, tts, "module_path!");
     let mod_path = &cx.current_expansion.module.mod_path;
@@ -82,7 +81,7 @@ pub fn expand_mod(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
 /// include! : parse the given file as an expr
 /// This is generally a bad idea because it's going to behave
 /// unhygienically.
-pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                            -> Box<dyn base::MacResult+'cx> {
     let file = match get_single_str_from_tts(cx, sp, tts, "include!") {
         Some(f) => f,
@@ -120,7 +119,7 @@ pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[tokenstream::T
 }
 
 // include_str! : read the given file, insert it as a literal string expr
-pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_include_str(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                           -> Box<dyn base::MacResult+'static> {
     let file = match get_single_str_from_tts(cx, sp, tts, "include_str!") {
         Some(f) => f,
@@ -148,7 +147,7 @@ pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenT
     }
 }
 
-pub fn expand_include_bytes(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::TokenTree])
+pub fn expand_include_bytes(cx: &mut ExtCtxt<'_>, sp: Span, tts: &[tokenstream::TokenTree])
                             -> Box<dyn base::MacResult+'static> {
     let file = match get_single_str_from_tts(cx, sp, tts, "include_bytes!") {
         Some(f) => f,
@@ -178,7 +177,7 @@ pub fn expand_include_bytes(cx: &mut ExtCtxt, sp: Span, tts: &[tokenstream::Toke
 
 // resolve a file-system path to an absolute file-system path (if it
 // isn't already)
-fn res_rel_file(cx: &mut ExtCtxt, sp: syntax_pos::Span, arg: String) -> PathBuf {
+fn res_rel_file(cx: &mut ExtCtxt<'_>, sp: syntax_pos::Span, arg: String) -> PathBuf {
     let arg = PathBuf::from(arg);
     // Relative paths are resolved relative to the file in which they are found
     // after macro expansion (that is, they are unhygienic).
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/tt/macro_parser.rs
index b4003ac729add..5de1ccec8609e 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/tt/macro_parser.rs
@@ -1,4 +1,4 @@
-//! This is an NFA-based parser, which calls out to the main rust parser for named nonterminals
+//! This is an NFA-based parser, which calls out to the main rust parser for named non-terminals
 //! (which it commits to fully when it hits one in a grammar). There's a set of current NFA threads
 //! and a set of next ones. Instead of NTs, we have a special case for Kleene star. The big-O, in
 //! pathological cases, is worse than traditional use of NFA or Earley parsing, but it's an easier
@@ -22,7 +22,7 @@
 //!
 //! As it processes them, it fills up `eof_items` with threads that would be valid if
 //! the macro invocation is now over, `bb_items` with threads that are waiting on
-//! a Rust nonterminal like `$e:expr`, and `next_items` with threads that are waiting
+//! a Rust non-terminal like `$e:expr`, and `next_items` with threads that are waiting
 //! on a particular token. Most of the logic concerns moving the · through the
 //! repetitions indicated by Kleene stars. The rules for moving the · without
 //! consuming any input are called epsilon transitions. It only advances or calls
@@ -70,21 +70,22 @@
 //! eof: [a $( a )* a b ·]
 //! ```
 
-pub use self::NamedMatch::*;
-pub use self::ParseResult::*;
-use self::TokenTreeOrTokenTreeSlice::*;
+pub use NamedMatch::*;
+pub use ParseResult::*;
+use TokenTreeOrTokenTreeSlice::*;
+
+use crate::ast::Ident;
+use crate::ext::tt::quoted::{self, TokenTree};
+use crate::parse::{Directory, ParseSess};
+use crate::parse::parser::{Parser, PathStyle};
+use crate::parse::token::{self, DocComment, Nonterminal, Token};
+use crate::print::pprust;
+use crate::symbol::keywords;
+use crate::tokenstream::{DelimSpan, TokenStream};
 
-use ast::Ident;
-use syntax_pos::{self, Span};
 use errors::FatalError;
-use ext::tt::quoted::{self, TokenTree};
-use parse::{Directory, ParseSess};
-use parse::parser::{Parser, PathStyle};
-use parse::token::{self, DocComment, Nonterminal, Token};
-use print::pprust;
-use smallvec::SmallVec;
-use symbol::keywords;
-use tokenstream::{DelimSpan, TokenStream};
+use smallvec::{smallvec, SmallVec};
+use syntax_pos::Span;
 
 use rustc_data_structures::fx::FxHashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
@@ -215,7 +216,7 @@ struct MatcherPos<'root, 'tt: 'root> {
 }
 
 impl<'root, 'tt> MatcherPos<'root, 'tt> {
-    /// Add `m` as a named match for the `idx`-th metavar.
+    /// Adds `m` as a named match for the `idx`-th metavar.
     fn push_match(&mut self, idx: usize, m: NamedMatch) {
         let matches = Rc::make_mut(&mut self.matches[idx]);
         matches.push(m);
@@ -303,7 +304,7 @@ fn create_matches(len: usize) -> Box<[Rc<NamedMatchVec>]> {
     }.into_boxed_slice()
 }
 
-/// Generate the top-level matcher position in which the "dot" is before the first token of the
+/// Generates the top-level matcher position in which the "dot" is before the first token of the
 /// matcher `ms` and we are going to start matching at the span `open` in the source.
 fn initial_matcher_pos<'root, 'tt>(ms: &'tt [TokenTree], open: Span) -> MatcherPos<'root, 'tt> {
     let match_idx_hi = count_names(ms);
@@ -336,7 +337,7 @@ fn initial_matcher_pos<'root, 'tt>(ms: &'tt [TokenTree], open: Span) -> MatcherP
 
 /// `NamedMatch` is a pattern-match result for a single `token::MATCH_NONTERMINAL`:
 /// so it is associated with a single ident in a parse, and all
-/// `MatchedNonterminal`s in the `NamedMatch` have the same nonterminal type
+/// `MatchedNonterminal`s in the `NamedMatch` have the same non-terminal type
 /// (expr, item, etc). Each leaf in a single `NamedMatch` corresponds to a
 /// single `token::MATCH_NONTERMINAL` in the `TokenTree` that produced it.
 ///
@@ -413,7 +414,7 @@ fn nameize<I: Iterator<Item = NamedMatch>>(
     Success(ret_val)
 }
 
-/// Generate an appropriate parsing failure message. For EOF, this is "unexpected end...". For
+/// Generates an appropriate parsing failure message. For EOF, this is "unexpected end...". For
 /// other tokens, this is "unexpected token...".
 pub fn parse_failure_msg(tok: Token) -> String {
     match tok {
@@ -425,7 +426,7 @@ pub fn parse_failure_msg(tok: Token) -> String {
     }
 }
 
-/// Perform a token equality check, ignoring syntax context (that is, an unhygienic comparison)
+/// Performs a token equality check, ignoring syntax context (that is, an unhygienic comparison)
 fn token_name_eq(t1: &Token, t2: &Token) -> bool {
     if let (Some((id1, is_raw1)), Some((id2, is_raw2))) = (t1.ident(), t2.ident()) {
         id1.name == id2.name && is_raw1 == is_raw2
@@ -649,7 +650,7 @@ pub fn parse(
     sess: &ParseSess,
     tts: TokenStream,
     ms: &[TokenTree],
-    directory: Option<Directory>,
+    directory: Option<Directory<'_>>,
     recurse_into_modules: bool,
 ) -> NamedParseResult {
     // Create a parser that can be used for the "black box" parts.
@@ -879,7 +880,7 @@ fn may_begin_with(name: &str, token: &Token) -> bool {
     }
 }
 
-/// A call to the "black-box" parser to parse some rust nonterminal.
+/// A call to the "black-box" parser to parse some Rust non-terminal.
 ///
 /// # Parameters
 ///
@@ -890,7 +891,7 @@ fn may_begin_with(name: &str, token: &Token) -> bool {
 ///
 /// # Returns
 ///
-/// The parsed nonterminal.
+/// The parsed non-terminal.
 fn parse_nt<'a>(p: &mut Parser<'a>, sp: Span, name: &str) -> Nonterminal {
     if name == "tt" {
         return token::NtTT(p.parse_token_tree());
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 24202ca8fbdc0..bd64bb010219b 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -1,24 +1,26 @@
-use {ast, attr};
-use syntax_pos::{Span, DUMMY_SP};
-use edition::Edition;
+use crate::{ast, attr};
+use crate::edition::Edition;
+use crate::ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
+use crate::ext::base::{NormalTT, TTMacroExpander};
+use crate::ext::expand::{AstFragment, AstFragmentKind};
+use crate::ext::tt::macro_parser::{Success, Error, Failure};
+use crate::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
+use crate::ext::tt::macro_parser::{parse, parse_failure_msg};
+use crate::ext::tt::quoted;
+use crate::ext::tt::transcribe::transcribe;
+use crate::feature_gate::Features;
+use crate::parse::{Directory, ParseSess};
+use crate::parse::parser::Parser;
+use crate::parse::token::{self, NtTT};
+use crate::parse::token::Token::*;
+use crate::symbol::Symbol;
+use crate::tokenstream::{DelimSpan, TokenStream, TokenTree};
+
 use errors::FatalError;
-use ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
-use ext::base::{NormalTT, TTMacroExpander};
-use ext::expand::{AstFragment, AstFragmentKind};
-use ext::tt::macro_parser::{Success, Error, Failure};
-use ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
-use ext::tt::macro_parser::{parse, parse_failure_msg};
-use ext::tt::quoted;
-use ext::tt::transcribe::transcribe;
-use feature_gate::Features;
-use parse::{Directory, ParseSess};
-use parse::parser::Parser;
-use parse::token::{self, NtTT};
-use parse::token::Token::*;
-use symbol::Symbol;
-use tokenstream::{DelimSpan, TokenStream, TokenTree};
-
-use rustc_data_structures::fx::FxHashMap;
+use syntax_pos::{Span, DUMMY_SP, symbol::Ident};
+use log::debug;
+
+use rustc_data_structures::fx::{FxHashMap};
 use std::borrow::Cow;
 use std::collections::hash_map::Entry;
 
@@ -91,7 +93,7 @@ struct MacroRulesMacroExpander {
 impl TTMacroExpander for MacroRulesMacroExpander {
     fn expand<'cx>(
         &self,
-        cx: &'cx mut ExtCtxt,
+        cx: &'cx mut ExtCtxt<'_>,
         sp: Span,
         input: TokenStream,
         def_span: Option<Span>,
@@ -109,13 +111,13 @@ impl TTMacroExpander for MacroRulesMacroExpander {
     }
 }
 
-fn trace_macros_note(cx: &mut ExtCtxt, sp: Span, message: String) {
+fn trace_macros_note(cx: &mut ExtCtxt<'_>, sp: Span, message: String) {
     let sp = sp.macro_backtrace().last().map(|trace| trace.call_site).unwrap_or(sp);
     cx.expansions.entry(sp).or_default().push(message);
 }
 
 /// Given `lhses` and `rhses`, this is the new macro we create
-fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
+fn generic_extension<'cx>(cx: &'cx mut ExtCtxt<'_>,
                           sp: Span,
                           def_span: Option<Span>,
                           name: ast::Ident,
@@ -221,7 +223,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
                     if comma_span.is_dummy() {
                         err.note("you might be missing a comma");
                     } else {
-                        err.span_suggestion_short_with_applicability(
+                        err.span_suggestion_short(
                             comma_span,
                             "missing comma here",
                             ", ".to_string(),
@@ -244,8 +246,12 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
 // Holy self-referential!
 
 /// Converts a `macro_rules!` invocation into a syntax extension.
-pub fn compile(sess: &ParseSess, features: &Features, def: &ast::Item, edition: Edition)
-               -> SyntaxExtension {
+pub fn compile(
+    sess: &ParseSess,
+    features: &Features,
+    def: &ast::Item,
+    edition: Edition
+) -> SyntaxExtension {
     let lhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("lhs"));
     let rhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("rhs"));
 
@@ -353,7 +359,13 @@ pub fn compile(sess: &ParseSess, features: &Features, def: &ast::Item, edition:
 
     // don't abort iteration early, so that errors for multiple lhses can be reported
     for lhs in &lhses {
-        valid &= check_lhs_no_empty_seq(sess, &[lhs.clone()])
+        valid &= check_lhs_no_empty_seq(sess, &[lhs.clone()]);
+        valid &= check_lhs_duplicate_matcher_bindings(
+            sess,
+            &[lhs.clone()],
+            &mut FxHashMap::default(),
+            def.id
+        );
     }
 
     let expander: Box<_> = Box::new(MacroRulesMacroExpander {
@@ -364,7 +376,24 @@ pub fn compile(sess: &ParseSess, features: &Features, def: &ast::Item, edition:
     });
 
     if body.legacy {
-        let allow_internal_unstable = attr::contains_name(&def.attrs, "allow_internal_unstable");
+        let allow_internal_unstable = attr::find_by_name(&def.attrs, "allow_internal_unstable")
+            .map(|attr| attr
+                .meta_item_list()
+                .map(|list| list.iter()
+                    .map(|it| it.name().unwrap_or_else(|| sess.span_diagnostic.span_bug(
+                        it.span, "allow internal unstable expects feature names",
+                    )))
+                    .collect::<Vec<Symbol>>().into()
+                )
+                .unwrap_or_else(|| {
+                    sess.span_diagnostic.span_warn(
+                        attr.span, "allow_internal_unstable expects list of feature names. In the \
+                        future this will become a hard error. Please use `allow_internal_unstable(\
+                        foo, bar)` to only allow the `foo` and `bar` features",
+                    );
+                    vec![Symbol::intern("allow_internal_unstable_backcompat_hack")].into()
+                })
+            );
         let allow_internal_unsafe = attr::contains_name(&def.attrs, "allow_internal_unsafe");
         let mut local_inner_macros = false;
         if let Some(macro_export) = attr::find_by_name(&def.attrs, "macro_export") {
@@ -420,10 +449,10 @@ fn check_lhs_nt_follows(sess: &ParseSess,
     // after parsing/expansion. we can report every error in every macro this way.
 }
 
-/// Check that the lhs contains no repetition which could match an empty token
+/// Checks that the lhs contains no repetition which could match an empty token
 /// tree, because then the matcher would hang indefinitely.
 fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
-    use self::quoted::TokenTree;
+    use quoted::TokenTree;
     for tt in tts {
         match *tt {
             TokenTree::Token(..) | TokenTree::MetaVar(..) | TokenTree::MetaVarDecl(..) => (),
@@ -435,7 +464,8 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
                     match *seq_tt {
                         TokenTree::MetaVarDecl(_, _, id) => id.name == "vis",
                         TokenTree::Sequence(_, ref sub_seq) =>
-                            sub_seq.op == quoted::KleeneOp::ZeroOrMore,
+                            sub_seq.op == quoted::KleeneOp::ZeroOrMore
+                            || sub_seq.op == quoted::KleeneOp::ZeroOrOne,
                         _ => false,
                     }
                 }) {
@@ -453,6 +483,53 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
     true
 }
 
+/// Check that the LHS contains no duplicate matcher bindings. e.g. `$a:expr, $a:expr` would be
+/// illegal, since it would be ambiguous which `$a` to use if we ever needed to.
+fn check_lhs_duplicate_matcher_bindings(
+    sess: &ParseSess,
+    tts: &[quoted::TokenTree],
+    metavar_names: &mut FxHashMap<Ident, Span>,
+    node_id: ast::NodeId,
+) -> bool {
+    use self::quoted::TokenTree;
+    use crate::early_buffered_lints::BufferedEarlyLintId;
+    for tt in tts {
+        match *tt {
+            TokenTree::MetaVarDecl(span, name, _kind) => {
+                if let Some(&prev_span) = metavar_names.get(&name) {
+                    // FIXME(mark-i-m): in a few cycles, make this a hard error.
+                    // sess.span_diagnostic
+                    //     .struct_span_err(span, "duplicate matcher binding")
+                    //     .span_note(prev_span, "previous declaration was here")
+                    //     .emit();
+                    sess.buffer_lint(
+                        BufferedEarlyLintId::DuplicateMacroMatcherBindingName,
+                        crate::source_map::MultiSpan::from(vec![prev_span, span]),
+                        node_id,
+                        "duplicate matcher binding"
+                    );
+                    return false;
+                } else {
+                    metavar_names.insert(name, span);
+                }
+            }
+            TokenTree::Delimited(_, ref del) => {
+                if !check_lhs_duplicate_matcher_bindings(sess, &del.tts, metavar_names, node_id) {
+                    return false;
+                }
+            },
+            TokenTree::Sequence(_, ref seq) => {
+                if !check_lhs_duplicate_matcher_bindings(sess, &seq.tts, metavar_names, node_id) {
+                    return false;
+                }
+            }
+            _ => {}
+        }
+    }
+
+    true
+}
+
 fn check_rhs(sess: &ParseSess, rhs: &quoted::TokenTree) -> bool {
     match *rhs {
         quoted::TokenTree::Delimited(..) => return true,
@@ -496,7 +573,7 @@ struct FirstSets {
 
 impl FirstSets {
     fn new(tts: &[quoted::TokenTree]) -> FirstSets {
-        use self::quoted::TokenTree;
+        use quoted::TokenTree;
 
         let mut sets = FirstSets { first: FxHashMap::default() };
         build_recur(&mut sets, tts);
@@ -543,7 +620,10 @@ impl FirstSets {
                         }
 
                         // Reverse scan: Sequence comes before `first`.
-                        if subfirst.maybe_empty || seq_rep.op == quoted::KleeneOp::ZeroOrMore {
+                        if subfirst.maybe_empty
+                           || seq_rep.op == quoted::KleeneOp::ZeroOrMore
+                           || seq_rep.op == quoted::KleeneOp::ZeroOrOne
+                        {
                             // If sequence is potentially empty, then
                             // union them (preserving first emptiness).
                             first.add_all(&TokenSet { maybe_empty: true, ..subfirst });
@@ -563,7 +643,7 @@ impl FirstSets {
     // walks forward over `tts` until all potential FIRST tokens are
     // identified.
     fn first(&self, tts: &[quoted::TokenTree]) -> TokenSet {
-        use self::quoted::TokenTree;
+        use quoted::TokenTree;
 
         let mut first = TokenSet::empty();
         for tt in tts.iter() {
@@ -591,8 +671,10 @@ impl FirstSets {
 
                             assert!(first.maybe_empty);
                             first.add_all(subfirst);
-                            if subfirst.maybe_empty ||
-                               seq_rep.op == quoted::KleeneOp::ZeroOrMore {
+                            if subfirst.maybe_empty
+                               || seq_rep.op == quoted::KleeneOp::ZeroOrMore
+                               || seq_rep.op == quoted::KleeneOp::ZeroOrOne
+                            {
                                 // continue scanning for more first
                                 // tokens, but also make sure we
                                 // restore empty-tracking state
@@ -715,7 +797,7 @@ fn check_matcher_core(sess: &ParseSess,
                       first_sets: &FirstSets,
                       matcher: &[quoted::TokenTree],
                       follow: &TokenSet) -> TokenSet {
-    use self::quoted::TokenTree;
+    use quoted::TokenTree;
 
     let mut last = TokenSet::empty();
 
@@ -895,8 +977,8 @@ fn token_can_be_followed_by_any(tok: &quoted::TokenTree) -> bool {
     }
 }
 
-/// True if a fragment of type `frag` can be followed by any sort of
-/// token.  We use this (among other things) as a useful approximation
+/// Returns `true` if a fragment of type `frag` can be followed by any sort of
+/// token. We use this (among other things) as a useful approximation
 /// for when `frag` can be followed by a repetition like `$(...)*` or
 /// `$(...)+`. In general, these can be a bit tricky to reason about,
 /// so we adopt a conservative position that says that any fragment
@@ -925,7 +1007,7 @@ enum IsInFollow {
     Invalid(String, &'static str),
 }
 
-/// True if `frag` can legally be followed by the token `tok`. For
+/// Returns `true` if `frag` can legally be followed by the token `tok`. For
 /// fragments that can consume an unbounded number of tokens, `tok`
 /// must be within a well-defined follow set. This is intended to
 /// guarantee future compatibility: for example, without this rule, if
@@ -934,7 +1016,7 @@ enum IsInFollow {
 /// separator.
 // when changing this do not forget to update doc/book/macros.md!
 fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
-    use self::quoted::TokenTree;
+    use quoted::TokenTree;
 
     if let TokenTree::Token(_, token::CloseDelim(_)) = *tok {
         // closing a token tree can never be matched by any fragment;
@@ -1066,7 +1148,7 @@ fn is_legal_fragment_specifier(_sess: &ParseSess,
 
 fn quoted_tt_to_string(tt: &quoted::TokenTree) -> String {
     match *tt {
-        quoted::TokenTree::Token(_, ref tok) => ::print::pprust::token_to_string(tok),
+        quoted::TokenTree::Token(_, ref tok) => crate::print::pprust::token_to_string(tok),
         quoted::TokenTree::MetaVar(_, name) => format!("${}", name),
         quoted::TokenTree::MetaVarDecl(_, name, kind) => format!("${}:{}", name, kind),
         _ => panic!("unexpected quoted::TokenTree::{{Sequence or Delimited}} \
diff --git a/src/libsyntax/ext/tt/quoted.rs b/src/libsyntax/ext/tt/quoted.rs
index b56871a18857f..255795f28c7a3 100644
--- a/src/libsyntax/ext/tt/quoted.rs
+++ b/src/libsyntax/ext/tt/quoted.rs
@@ -1,13 +1,14 @@
-use ast::NodeId;
-use early_buffered_lints::BufferedEarlyLintId;
-use ext::tt::macro_parser;
-use feature_gate::Features;
-use parse::{token, ParseSess};
-use print::pprust;
-use symbol::keywords;
+use crate::ast::NodeId;
+use crate::early_buffered_lints::BufferedEarlyLintId;
+use crate::ext::tt::macro_parser;
+use crate::feature_gate::Features;
+use crate::parse::{token, ParseSess};
+use crate::print::pprust;
+use crate::tokenstream::{self, DelimSpan};
+use crate::ast;
+use crate::symbol::keywords;
+
 use syntax_pos::{edition::Edition, BytePos, Span};
-use tokenstream::{self, DelimSpan};
-use ast;
 
 use rustc_data_structures::sync::Lrc;
 use std::iter::Peekable;
@@ -21,17 +22,17 @@ pub struct Delimited {
 }
 
 impl Delimited {
-    /// Return the opening delimiter (possibly `NoDelim`).
+    /// Returns the opening delimiter (possibly `NoDelim`).
     pub fn open_token(&self) -> token::Token {
         token::OpenDelim(self.delim)
     }
 
-    /// Return the closing delimiter (possibly `NoDelim`).
+    /// Returns the closing delimiter (possibly `NoDelim`).
     pub fn close_token(&self) -> token::Token {
         token::CloseDelim(self.delim)
     }
 
-    /// Return a `self::TokenTree` with a `Span` corresponding to the opening delimiter.
+    /// Returns a `self::TokenTree` with a `Span` corresponding to the opening delimiter.
     pub fn open_tt(&self, span: Span) -> TokenTree {
         let open_span = if span.is_dummy() {
             span
@@ -41,7 +42,7 @@ impl Delimited {
         TokenTree::Token(open_span, self.open_token())
     }
 
-    /// Return a `self::TokenTree` with a `Span` corresponding to the closing delimiter.
+    /// Returns a `self::TokenTree` with a `Span` corresponding to the closing delimiter.
     pub fn close_tt(&self, span: Span) -> TokenTree {
         let close_span = if span.is_dummy() {
             span
@@ -106,7 +107,7 @@ impl TokenTree {
         }
     }
 
-    /// Returns true if the given token tree contains no other tokens. This is vacuously true for
+    /// Returns `true` if the given token tree contains no other tokens. This is vacuously true for
     /// single tokens or metavar/decls, but may be false for delimited trees or sequences.
     pub fn is_empty(&self) -> bool {
         match *self {
@@ -119,7 +120,7 @@ impl TokenTree {
         }
     }
 
-    /// Get the `index`-th sub-token-tree. This only makes sense for delimited trees and sequences.
+    /// Gets the `index`-th sub-token-tree. This only makes sense for delimited trees and sequences.
     pub fn get_tt(&self, index: usize) -> TokenTree {
         match (self, index) {
             (&TokenTree::Delimited(_, ref delimed), _) if delimed.delim == token::NoDelim => {
@@ -139,7 +140,7 @@ impl TokenTree {
         }
     }
 
-    /// Retrieve the `TokenTree`'s span.
+    /// Retrieves the `TokenTree`'s span.
     pub fn span(&self) -> Span {
         match *self {
             TokenTree::Token(sp, _)
@@ -410,8 +411,8 @@ where
 /// operator and separator, then a tuple with `(separator, KleeneOp)` is returned. Otherwise, an
 /// error with the appropriate span is emitted to `sess` and a dummy value is returned.
 ///
-/// NOTE: In 2015 edition, * and + are the only Kleene operators and `?` is a separator. In 2018,
-/// `?` is a Kleene op and not a separator.
+/// N.B., in the 2015 edition, `*` and `+` are the only Kleene operators, and `?` is a separator.
+/// In the 2018 edition however, `?` is a Kleene operator, and not a separator.
 fn parse_sep_and_kleene_op<I>(
     input: &mut Peekable<I>,
     span: Span,
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index 0ef2d3b749d81..b9a50cc6488dd 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -1,13 +1,14 @@
-use ast::Ident;
-use ext::base::ExtCtxt;
-use ext::expand::Marker;
-use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
-use ext::tt::quoted;
-use fold::noop_fold_tt;
-use parse::token::{self, Token, NtTT};
-use smallvec::SmallVec;
+use crate::ast::Ident;
+use crate::ext::base::ExtCtxt;
+use crate::ext::expand::Marker;
+use crate::ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
+use crate::ext::tt::quoted;
+use crate::mut_visit::noop_visit_tt;
+use crate::parse::token::{self, Token, NtTT};
+use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
+
+use smallvec::{smallvec, SmallVec};
 use syntax_pos::DUMMY_SP;
-use tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
@@ -56,7 +57,7 @@ impl Iterator for Frame {
 /// This can do Macro-By-Example transcription. On the other hand, if
 /// `src` contains no `TokenTree::{Sequence, MetaVar, MetaVarDecl}`s, `interp` can
 /// (and should) be None.
-pub fn transcribe(cx: &ExtCtxt,
+pub fn transcribe(cx: &ExtCtxt<'_>,
                   interp: Option<FxHashMap<Ident, Rc<NamedMatch>>>,
                   src: Vec<quoted::TokenTree>)
                   -> TokenStream {
@@ -170,7 +171,9 @@ pub fn transcribe(cx: &ExtCtxt,
             }
             quoted::TokenTree::Token(sp, tok) => {
                 let mut marker = Marker(cx.current_expansion.mark);
-                result.push(noop_fold_tt(TokenTree::Token(sp, tok), &mut marker).into())
+                let mut tt = TokenTree::Token(sp, tok);
+                noop_visit_tt(&mut tt, &mut marker);
+                result.push(tt.into());
             }
             quoted::TokenTree::MetaVarDecl(..) => panic!("unexpected `TokenTree::MetaVarDecl"),
         }
@@ -228,7 +231,7 @@ fn lockstep_iter_size(tree: &quoted::TokenTree,
                       interpolations: &FxHashMap<Ident, Rc<NamedMatch>>,
                       repeats: &[(usize, usize)])
                       -> LockstepIterSize {
-    use self::quoted::TokenTree;
+    use quoted::TokenTree;
     match *tree {
         TokenTree::Delimited(_, ref delimed) => {
             delimed.tts.iter().fold(LockstepIterSize::Unconstrained, |size, tt| {
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 9b54e8f9c1f2c..d574b410ccc06 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -12,21 +12,23 @@
 //! gate usage is added, *do not remove it again* even once the feature
 //! becomes stable.
 
-use self::AttributeType::*;
-use self::AttributeGate::*;
+use AttributeType::*;
+use AttributeGate::*;
+
+use crate::ast::{self, NodeId, GenericParam, GenericParamKind, PatKind, RangeEnd};
+use crate::attr;
+use crate::early_buffered_lints::BufferedEarlyLintId;
+use crate::source_map::Spanned;
+use crate::edition::{ALL_EDITIONS, Edition};
+use crate::visit::{self, FnKind, Visitor};
+use crate::parse::ParseSess;
+use crate::symbol::Symbol;
 
+use errors::{DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_target::spec::abi::Abi;
-use ast::{self, NodeId, PatKind, RangeEnd};
-use attr;
-use early_buffered_lints::BufferedEarlyLintId;
-use source_map::Spanned;
-use edition::{ALL_EDITIONS, Edition};
 use syntax_pos::{Span, DUMMY_SP};
-use errors::{DiagnosticBuilder, Handler};
-use visit::{self, FnKind, Visitor};
-use parse::ParseSess;
-use symbol::Symbol;
+use log::debug;
 
 use std::env;
 
@@ -124,7 +126,6 @@ declare_features! (
 
     (active, link_llvm_intrinsics, "1.0.0", Some(29602), None),
     (active, linkage, "1.0.0", Some(29603), None),
-    (active, quote, "1.0.0", Some(29601), None),
 
     // rustc internal
     (active, rustc_diagnostic_macros, "1.0.0", None, None),
@@ -395,6 +396,7 @@ declare_features! (
     (active, wasm_target_feature, "1.30.0", Some(44839), None),
     (active, adx_target_feature, "1.32.0", Some(44839), None),
     (active, cmpxchg16b_target_feature, "1.32.0", Some(44839), None),
+    (active, movbe_target_feature, "1.34.0", Some(44839), None),
 
     // Allows macro invocations on modules expressions and statements and
     // procedural macros to expand to non-items.
@@ -454,14 +456,20 @@ declare_features! (
     // Adds `reason` and `expect` lint attributes.
     (active, lint_reasons, "1.31.0", Some(54503), None),
 
-    // `extern crate self as foo;` puts local crate root into extern prelude under name `foo`.
-    (active, extern_crate_self, "1.31.0", Some(56409), None),
-
     // Allows paths to enum variants on type aliases.
     (active, type_alias_enum_variants, "1.31.0", Some(49683), None),
 
     // Re-Rebalance coherence
     (active, re_rebalance_coherence, "1.32.0", Some(55437), None),
+
+    // Const generic types.
+    (active, const_generics, "1.34.0", Some(44580), None),
+
+    // #[optimize(X)]
+    (active, optimize_attribute, "1.34.0", Some(54882), None),
+
+    // #[repr(align(X))] on enums
+    (active, repr_align_enum, "1.34.0", Some(57996), None),
 );
 
 declare_features! (
@@ -504,6 +512,7 @@ declare_features! (
     // Paths of the form: `extern::foo::bar`
     (removed, extern_in_paths, "1.33.0", Some(55600), None,
      Some("subsumed by `::foo::bar` paths")),
+    (removed, quote, "1.0.0", Some(29601), None, None),
 );
 
 declare_features! (
@@ -664,6 +673,8 @@ declare_features! (
     (accepted, self_struct_ctor, "1.32.0", Some(51994), None),
     // `Self` in type definitions (RFC 2300)
     (accepted, self_in_typedefs, "1.32.0", Some(49303), None),
+    // Allows `use x::y;` to search `x` in the current scope.
+    (accepted, uniform_paths, "1.32.0", Some(53130), None),
     // Integer match exhaustiveness checking (RFC 2591)
     (accepted, exhaustive_integer_patterns, "1.33.0", Some(50907), None),
     // `use path as _;` and `extern crate c as _;`
@@ -682,10 +693,10 @@ declare_features! (
     (accepted, cfg_attr_multi, "1.33.0", Some(54881), None),
     // Top level or-patterns (`p | q`) in `if let` and `while let`.
     (accepted, if_while_or_patterns, "1.33.0", Some(48215), None),
-    // Allows `use x::y;` to search `x` in the current scope.
-    (accepted, uniform_paths, "1.32.0", Some(53130), None),
     // Allows `cfg(target_vendor = "...")`.
     (accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
+    // `extern crate self as foo;` puts local crate root into extern prelude under name `foo`.
+    (accepted, extern_crate_self, "1.34.0", Some(56409), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must
@@ -726,7 +737,7 @@ pub struct AttributeTemplate {
 }
 
 impl AttributeTemplate {
-    /// Check that the given meta-item is compatible with this template.
+    /// Checks that the given meta-item is compatible with this template.
     fn compatible(&self, meta_item_kind: &ast::MetaItemKind) -> bool {
         match meta_item_kind {
             ast::MetaItemKind::Word => self.word,
@@ -738,7 +749,7 @@ impl AttributeTemplate {
 }
 
 /// A convenience macro for constructing attribute templates.
-/// E.g. `template!(Word, List: "description")` means that the attribute
+/// E.g., `template!(Word, List: "description")` means that the attribute
 /// supports forms `#[attr]` and `#[attr(description)]`.
 macro_rules! template {
     (Word) => { template!(@ true, None, None) };
@@ -775,8 +786,8 @@ pub enum Stability {
 }
 
 // fn() is not Debug
-impl ::std::fmt::Debug for AttributeGate {
-    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+impl std::fmt::Debug for AttributeGate {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match *self {
             Gated(ref stab, name, expl, _) =>
                 write!(fmt, "Gated({:?}, {}, {})", stab, name, expl),
@@ -938,6 +949,13 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
                                       is just used for rustc unit tests \
                                       and will never be stable",
                                      cfg_fn!(rustc_attrs))),
+    ("rustc_layout", Normal, template!(List: "field1, field2, ..."),
+     Gated(Stability::Unstable,
+           "rustc_attrs",
+           "the `#[rustc_layout]` attribute \
+            is just used for rustc unit tests \
+            and will never be stable",
+           cfg_fn!(rustc_attrs))),
     ("rustc_regions", Normal, template!(Word), Gated(Stability::Unstable,
                                     "rustc_attrs",
                                     "the `#[rustc_regions]` attribute \
@@ -1073,7 +1091,8 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
                                               stable",
                                              cfg_fn!(profiler_runtime))),
 
-    ("allow_internal_unstable", Normal, template!(Word), Gated(Stability::Unstable,
+    ("allow_internal_unstable", Normal, template!(Word, List: "feat1, feat2, ..."),
+                                              Gated(Stability::Unstable,
                                               "allow_internal_unstable",
                                               EXPLAIN_ALLOW_INTERNAL_UNSTABLE,
                                               cfg_fn!(allow_internal_unstable))),
@@ -1166,9 +1185,15 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
     ("stable", Whitelisted, template!(List: r#"feature = "name", since = "version""#), Ungated),
     ("unstable", Whitelisted, template!(List: r#"feature = "name", reason = "...", issue = "N""#),
                                         Ungated),
-    ("deprecated", Normal, template!(Word, List: r#"/*opt*/ since = "version",
-                                                    /*opt*/ note = "reason"#,
-                                                    NameValueStr: "reason"), Ungated),
+    ("deprecated",
+        Normal,
+        template!(
+            Word,
+            List: r#"/*opt*/ since = "version", /*opt*/ note = "reason"#,
+            NameValueStr: "reason"
+        ),
+        Ungated
+    ),
 
     ("rustc_paren_sugar", Normal, template!(Word), Gated(Stability::Unstable,
                                         "unboxed_closures",
@@ -1181,7 +1206,7 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
     ("proc_macro", Normal, template!(Word), Ungated),
 
     ("rustc_proc_macro_decls", Normal, template!(Word), Gated(Stability::Unstable,
-                                             "rustc_proc_macro_decls",
+                                             "rustc_attrs",
                                              "used internally by rustc",
                                              cfg_fn!(rustc_attrs))),
 
@@ -1215,6 +1240,12 @@ pub const BUILTIN_ATTRIBUTES: &[(&str, AttributeType, AttributeTemplate, Attribu
                            "#[alloc_error_handler] is an unstable feature",
                            cfg_fn!(alloc_error_handler))),
 
+    // RFC 2412
+    ("optimize", Whitelisted, template!(List: "size|speed"), Gated(Stability::Unstable,
+                               "optimize_attribute",
+                               "#[optimize] attribute is an unstable feature",
+                               cfg_fn!(optimize_attribute))),
+
     // Crate level attributes
     ("crate_name", CrateLevel, template!(NameValueStr: "name"), Ungated),
     ("crate_type", CrateLevel, template!(NameValueStr: "bin|lib|..."), Ungated),
@@ -1260,7 +1291,7 @@ impl GatedCfg {
 
     pub fn check_and_emit(&self, sess: &ParseSess, features: &Features) {
         let (cfg, feature, has_feature) = GATED_CFGS[self.index];
-        if !has_feature(features) && !self.span.allows_unstable() {
+        if !has_feature(features) && !self.span.allows_unstable(feature) {
             let explain = format!("`cfg({})` is experimental and subject to change", cfg);
             emit_feature_err(sess, feature, self.span, GateIssue::Language, &explain);
         }
@@ -1279,7 +1310,7 @@ macro_rules! gate_feature_fn {
              name, explain, level) = ($cx, $has_feature, $span, $name, $explain, $level);
         let has_feature: bool = has_feature(&$cx.features);
         debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature);
-        if !has_feature && !span.allows_unstable() {
+        if !has_feature && !span.allows_unstable($name) {
             leveled_feature_err(cx.parse_sess, name, span, GateIssue::Language, explain, level)
                 .emit();
         }
@@ -1304,7 +1335,11 @@ impl<'a> Context<'a> {
         for &(n, ty, _template, ref gateage) in BUILTIN_ATTRIBUTES {
             if name == n {
                 if let Gated(_, name, desc, ref has_feature) = *gateage {
-                    gate_feature_fn!(self, has_feature, attr.span, name, desc, GateStrength::Hard);
+                    if !attr.span.allows_unstable(name) {
+                        gate_feature_fn!(
+                            self, has_feature, attr.span, name, desc, GateStrength::Hard
+                        );
+                    }
                 } else if name == "doc" {
                     if let Some(content) = attr.meta_item_list() {
                         if content.iter().any(|c| c.check_name("include")) {
@@ -1469,13 +1504,13 @@ struct PostExpansionVisitor<'a> {
 macro_rules! gate_feature_post {
     ($cx: expr, $feature: ident, $span: expr, $explain: expr) => {{
         let (cx, span) = ($cx, $span);
-        if !span.allows_unstable() {
+        if !span.allows_unstable(stringify!($feature)) {
             gate_feature!(cx.context, $feature, span, $explain)
         }
     }};
     ($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {{
         let (cx, span) = ($cx, $span);
-        if !span.allows_unstable() {
+        if !span.allows_unstable(stringify!($feature)) {
             gate_feature!(cx.context, $feature, span, $explain, $level)
         }
     }}
@@ -1586,10 +1621,8 @@ impl<'a> PostExpansionVisitor<'a> {
 
 impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
     fn visit_attribute(&mut self, attr: &ast::Attribute) {
-        if !attr.span.allows_unstable() {
-            // check for gated attributes
-            self.context.check_attribute(attr, false);
-        }
+        // check for gated attributes
+        self.context.check_attribute(attr, false);
 
         if attr.check_name("doc") {
             if let Some(content) = attr.meta_item_list() {
@@ -1682,6 +1715,17 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 }
             }
 
+            ast::ItemKind::Enum(..) => {
+                for attr in attr::filter_by_name(&i.attrs[..], "repr") {
+                    for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
+                        if item.check_name("align") {
+                            gate_feature_post!(&self, repr_align_enum, attr.span,
+                                               "`#[repr(align(x))]` on enums is experimental");
+                        }
+                    }
+                }
+            }
+
             ast::ItemKind::Impl(_, polarity, defaultness, _, _, _, _) => {
                 if polarity == ast::ImplPolarity::Negative {
                     gate_feature_post!(&self, optin_builtin_traits,
@@ -1867,6 +1911,14 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         visit::walk_fn(self, fn_kind, fn_decl, span);
     }
 
+    fn visit_generic_param(&mut self, param: &'a GenericParam) {
+        if let GenericParamKind::Const { .. } = param.kind {
+            gate_feature_post!(&self, const_generics, param.ident.span,
+                "const generics are unstable");
+        }
+        visit::walk_generic_param(self, param);
+    }
+
     fn visit_trait_item(&mut self, ti: &'a ast::TraitItem) {
         match ti.node {
             ast::TraitItemKind::Method(ref sig, ref block) => {
@@ -1952,7 +2004,7 @@ pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute],
     // Some features are known to be incomplete and using them is likely to have
     // unanticipated results, such as compiler crashes. We warn the user about these
     // to alert them.
-    let incomplete_features = ["generic_associated_types"];
+    let incomplete_features = ["generic_associated_types", "const_generics"];
 
     let mut features = Features::new();
     let mut edition_enabled_features = FxHashMap::default();
@@ -2102,8 +2154,7 @@ pub fn check_crate(krate: &ast::Crate,
 
 #[derive(Clone, Copy, Hash)]
 pub enum UnstableFeatures {
-    /// Hard errors for unstable features are active, as on
-    /// beta/stable channels.
+    /// Hard errors for unstable features are active, as on beta/stable channels.
     Disallow,
     /// Allow features to be activated, as on nightly.
     Allow,
diff --git a/src/libsyntax/fold.rs b/src/libsyntax/fold.rs
deleted file mode 100644
index 8ac103856dcd1..0000000000000
--- a/src/libsyntax/fold.rs
+++ /dev/null
@@ -1,1495 +0,0 @@
-//! A Folder represents an AST->AST fold; it accepts an AST piece,
-//! and returns a piece of the same type. So, for instance, macro
-//! expansion is a Folder that walks over an AST and produces another
-//! AST.
-//!
-//! Note: using a Folder (other than the MacroExpander Folder) on
-//! an AST before macro expansion is probably a bad idea. For instance,
-//! a folder renaming item names in a module will miss all of those
-//! that are created by the expansion of a macro.
-
-use ast::*;
-use ast;
-use syntax_pos::Span;
-use source_map::{Spanned, respan};
-use parse::token::{self, Token};
-use ptr::P;
-use smallvec::{Array, SmallVec};
-use symbol::keywords;
-use ThinVec;
-use tokenstream::*;
-use util::move_map::MoveMap;
-
-use rustc_data_structures::sync::Lrc;
-
-pub trait ExpectOne<A: Array> {
-    fn expect_one(self, err: &'static str) -> A::Item;
-}
-
-impl<A: Array> ExpectOne<A> for SmallVec<A> {
-    fn expect_one(self, err: &'static str) -> A::Item {
-        assert!(self.len() == 1, err);
-        self.into_iter().next().unwrap()
-    }
-}
-
-pub trait Folder : Sized {
-    // Any additions to this trait should happen in form
-    // of a call to a public `noop_*` function that only calls
-    // out to the folder again, not other `noop_*` functions.
-    //
-    // This is a necessary API workaround to the problem of not
-    // being able to call out to the super default method
-    // in an overridden default method.
-
-    fn fold_crate(&mut self, c: Crate) -> Crate {
-        noop_fold_crate(c, self)
-    }
-
-    fn fold_meta_items(&mut self, meta_items: Vec<MetaItem>) -> Vec<MetaItem> {
-        noop_fold_meta_items(meta_items, self)
-    }
-
-    fn fold_meta_list_item(&mut self, list_item: NestedMetaItem) -> NestedMetaItem {
-        noop_fold_meta_list_item(list_item, self)
-    }
-
-    fn fold_meta_item(&mut self, meta_item: MetaItem) -> MetaItem {
-        noop_fold_meta_item(meta_item, self)
-    }
-
-    fn fold_use_tree(&mut self, use_tree: UseTree) -> UseTree {
-        noop_fold_use_tree(use_tree, self)
-    }
-
-    fn fold_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
-        noop_fold_foreign_item(ni, self)
-    }
-
-    fn fold_foreign_item_simple(&mut self, ni: ForeignItem) -> ForeignItem {
-        noop_fold_foreign_item_simple(ni, self)
-    }
-
-    fn fold_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
-        noop_fold_item(i, self)
-    }
-
-    fn fold_item_simple(&mut self, i: Item) -> Item {
-        noop_fold_item_simple(i, self)
-    }
-
-    fn fold_fn_header(&mut self, header: FnHeader) -> FnHeader {
-        noop_fold_fn_header(header, self)
-    }
-
-    fn fold_struct_field(&mut self, sf: StructField) -> StructField {
-        noop_fold_struct_field(sf, self)
-    }
-
-    fn fold_item_kind(&mut self, i: ItemKind) -> ItemKind {
-        noop_fold_item_kind(i, self)
-    }
-
-    fn fold_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
-        noop_fold_trait_item(i, self)
-    }
-
-    fn fold_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
-        noop_fold_impl_item(i, self)
-    }
-
-    fn fold_fn_decl(&mut self, d: P<FnDecl>) -> P<FnDecl> {
-        noop_fold_fn_decl(d, self)
-    }
-
-    fn fold_asyncness(&mut self, a: IsAsync) -> IsAsync {
-        noop_fold_asyncness(a, self)
-    }
-
-    fn fold_block(&mut self, b: P<Block>) -> P<Block> {
-        noop_fold_block(b, self)
-    }
-
-    fn fold_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
-        noop_fold_stmt(s, self)
-    }
-
-    fn fold_arm(&mut self, a: Arm) -> Arm {
-        noop_fold_arm(a, self)
-    }
-
-    fn fold_guard(&mut self, g: Guard) -> Guard {
-        noop_fold_guard(g, self)
-    }
-
-    fn fold_pat(&mut self, p: P<Pat>) -> P<Pat> {
-        noop_fold_pat(p, self)
-    }
-
-    fn fold_anon_const(&mut self, c: AnonConst) -> AnonConst {
-        noop_fold_anon_const(c, self)
-    }
-
-    fn fold_expr(&mut self, e: P<Expr>) -> P<Expr> {
-        e.map(|e| noop_fold_expr(e, self))
-    }
-
-    fn fold_range_end(&mut self, re: RangeEnd) -> RangeEnd {
-        noop_fold_range_end(re, self)
-    }
-
-    fn fold_opt_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
-        noop_fold_opt_expr(e, self)
-    }
-
-    fn fold_exprs(&mut self, es: Vec<P<Expr>>) -> Vec<P<Expr>> {
-        noop_fold_exprs(es, self)
-    }
-
-    fn fold_generic_arg(&mut self, arg: GenericArg) -> GenericArg {
-        match arg {
-            GenericArg::Lifetime(lt) => GenericArg::Lifetime(self.fold_lifetime(lt)),
-            GenericArg::Type(ty) => GenericArg::Type(self.fold_ty(ty)),
-        }
-    }
-
-    fn fold_ty(&mut self, t: P<Ty>) -> P<Ty> {
-        noop_fold_ty(t, self)
-    }
-
-    fn fold_lifetime(&mut self, l: Lifetime) -> Lifetime {
-        noop_fold_lifetime(l, self)
-    }
-
-    fn fold_ty_binding(&mut self, t: TypeBinding) -> TypeBinding {
-        noop_fold_ty_binding(t, self)
-    }
-
-    fn fold_mod(&mut self, m: Mod) -> Mod {
-        noop_fold_mod(m, self)
-    }
-
-    fn fold_foreign_mod(&mut self, nm: ForeignMod) -> ForeignMod {
-        noop_fold_foreign_mod(nm, self)
-    }
-
-    fn fold_global_asm(&mut self, ga: P<GlobalAsm>) -> P<GlobalAsm> {
-        noop_fold_global_asm(ga, self)
-    }
-
-    fn fold_variant(&mut self, v: Variant) -> Variant {
-        noop_fold_variant(v, self)
-    }
-
-    fn fold_ident(&mut self, i: Ident) -> Ident {
-        noop_fold_ident(i, self)
-    }
-
-    fn fold_usize(&mut self, i: usize) -> usize {
-        noop_fold_usize(i, self)
-    }
-
-    fn fold_path(&mut self, p: Path) -> Path {
-        noop_fold_path(p, self)
-    }
-
-    fn fold_qpath(&mut self, qs: Option<QSelf>, p: Path) -> (Option<QSelf>, Path) {
-        noop_fold_qpath(qs, p, self)
-    }
-
-    fn fold_generic_args(&mut self, p: GenericArgs) -> GenericArgs {
-        noop_fold_generic_args(p, self)
-    }
-
-    fn fold_angle_bracketed_parameter_data(&mut self, p: AngleBracketedArgs)
-                                           -> AngleBracketedArgs
-    {
-        noop_fold_angle_bracketed_parameter_data(p, self)
-    }
-
-    fn fold_parenthesized_parameter_data(&mut self, p: ParenthesisedArgs)
-                                         -> ParenthesisedArgs
-    {
-        noop_fold_parenthesized_parameter_data(p, self)
-    }
-
-    fn fold_local(&mut self, l: P<Local>) -> P<Local> {
-        noop_fold_local(l, self)
-    }
-
-    fn fold_mac(&mut self, _mac: Mac) -> Mac {
-        panic!("fold_mac disabled by default");
-        // N.B., see note about macros above.
-        // if you really want a folder that
-        // works on macros, use this
-        // definition in your trait impl:
-        // fold::noop_fold_mac(_mac, self)
-    }
-
-    fn fold_macro_def(&mut self, def: MacroDef) -> MacroDef {
-        noop_fold_macro_def(def, self)
-    }
-
-    fn fold_label(&mut self, label: Label) -> Label {
-        noop_fold_label(label, self)
-    }
-
-    fn fold_attribute(&mut self, at: Attribute) -> Option<Attribute> {
-        noop_fold_attribute(at, self)
-    }
-
-    fn fold_arg(&mut self, a: Arg) -> Arg {
-        noop_fold_arg(a, self)
-    }
-
-    fn fold_generics(&mut self, generics: Generics) -> Generics {
-        noop_fold_generics(generics, self)
-    }
-
-    fn fold_trait_ref(&mut self, p: TraitRef) -> TraitRef {
-        noop_fold_trait_ref(p, self)
-    }
-
-    fn fold_poly_trait_ref(&mut self, p: PolyTraitRef) -> PolyTraitRef {
-        noop_fold_poly_trait_ref(p, self)
-    }
-
-    fn fold_variant_data(&mut self, vdata: VariantData) -> VariantData {
-        noop_fold_variant_data(vdata, self)
-    }
-
-    fn fold_generic_param(&mut self, param: GenericParam) -> GenericParam {
-        noop_fold_generic_param(param, self)
-    }
-
-    fn fold_generic_params(&mut self, params: Vec<GenericParam>) -> Vec<GenericParam> {
-        noop_fold_generic_params(params, self)
-    }
-
-    fn fold_tt(&mut self, tt: TokenTree) -> TokenTree {
-        noop_fold_tt(tt, self)
-    }
-
-    fn fold_tts(&mut self, tts: TokenStream) -> TokenStream {
-        noop_fold_tts(tts, self)
-    }
-
-    fn fold_token(&mut self, t: token::Token) -> token::Token {
-        noop_fold_token(t, self)
-    }
-
-    fn fold_interpolated(&mut self, nt: token::Nonterminal) -> token::Nonterminal {
-        noop_fold_interpolated(nt, self)
-    }
-
-    fn fold_opt_bounds(&mut self, b: Option<GenericBounds>) -> Option<GenericBounds> {
-        noop_fold_opt_bounds(b, self)
-    }
-
-    fn fold_bounds(&mut self, b: GenericBounds) -> GenericBounds {
-        noop_fold_bounds(b, self)
-    }
-
-    fn fold_param_bound(&mut self, tpb: GenericBound) -> GenericBound {
-        noop_fold_param_bound(tpb, self)
-    }
-
-    fn fold_mt(&mut self, mt: MutTy) -> MutTy {
-        noop_fold_mt(mt, self)
-    }
-
-    fn fold_field(&mut self, field: Field) -> Field {
-        noop_fold_field(field, self)
-    }
-
-    fn fold_where_clause(&mut self, where_clause: WhereClause)
-                         -> WhereClause {
-        noop_fold_where_clause(where_clause, self)
-    }
-
-    fn fold_where_predicate(&mut self, where_predicate: WherePredicate)
-                            -> WherePredicate {
-        noop_fold_where_predicate(where_predicate, self)
-    }
-
-    fn fold_vis(&mut self, vis: Visibility) -> Visibility {
-        noop_fold_vis(vis, self)
-    }
-
-    fn new_id(&mut self, i: NodeId) -> NodeId {
-        i
-    }
-
-    fn new_span(&mut self, sp: Span) -> Span {
-        sp
-    }
-}
-
-pub fn noop_fold_meta_items<T: Folder>(meta_items: Vec<MetaItem>, fld: &mut T) -> Vec<MetaItem> {
-    meta_items.move_map(|x| fld.fold_meta_item(x))
-}
-
-pub fn noop_fold_use_tree<T: Folder>(use_tree: UseTree, fld: &mut T) -> UseTree {
-    UseTree {
-        span: fld.new_span(use_tree.span),
-        prefix: fld.fold_path(use_tree.prefix),
-        kind: match use_tree.kind {
-            UseTreeKind::Simple(rename, id1, id2) =>
-                UseTreeKind::Simple(rename.map(|ident| fld.fold_ident(ident)),
-                                    fld.new_id(id1), fld.new_id(id2)),
-            UseTreeKind::Glob => UseTreeKind::Glob,
-            UseTreeKind::Nested(items) => UseTreeKind::Nested(items.move_map(|(tree, id)| {
-                (fld.fold_use_tree(tree), fld.new_id(id))
-            })),
-        },
-    }
-}
-
-pub fn fold_attrs<T: Folder>(attrs: Vec<Attribute>, fld: &mut T) -> Vec<Attribute> {
-    attrs.move_flat_map(|x| fld.fold_attribute(x))
-}
-
-pub fn fold_thin_attrs<T: Folder>(attrs: ThinVec<Attribute>, fld: &mut T) -> ThinVec<Attribute> {
-    fold_attrs(attrs.into(), fld).into()
-}
-
-pub fn noop_fold_arm<T: Folder>(Arm {attrs, pats, guard, body}: Arm,
-    fld: &mut T) -> Arm {
-    Arm {
-        attrs: fold_attrs(attrs, fld),
-        pats: pats.move_map(|x| fld.fold_pat(x)),
-        guard: guard.map(|x| fld.fold_guard(x)),
-        body: fld.fold_expr(body),
-    }
-}
-
-pub fn noop_fold_guard<T: Folder>(g: Guard, fld: &mut T) -> Guard {
-    match g {
-        Guard::If(e) => Guard::If(fld.fold_expr(e)),
-    }
-}
-
-pub fn noop_fold_ty_binding<T: Folder>(b: TypeBinding, fld: &mut T) -> TypeBinding {
-    TypeBinding {
-        id: fld.new_id(b.id),
-        ident: fld.fold_ident(b.ident),
-        ty: fld.fold_ty(b.ty),
-        span: fld.new_span(b.span),
-    }
-}
-
-pub fn noop_fold_ty<T: Folder>(t: P<Ty>, fld: &mut T) -> P<Ty> {
-    t.map(|Ty {id, node, span}| Ty {
-        id: fld.new_id(id),
-        node: match node {
-            TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => node,
-            TyKind::Slice(ty) => TyKind::Slice(fld.fold_ty(ty)),
-            TyKind::Ptr(mt) => TyKind::Ptr(fld.fold_mt(mt)),
-            TyKind::Rptr(region, mt) => {
-                TyKind::Rptr(region.map(|lt| noop_fold_lifetime(lt, fld)), fld.fold_mt(mt))
-            }
-            TyKind::BareFn(f) => {
-                TyKind::BareFn(f.map(|BareFnTy {generic_params, unsafety, abi, decl}| BareFnTy {
-                    generic_params: fld.fold_generic_params(generic_params),
-                    unsafety,
-                    abi,
-                    decl: fld.fold_fn_decl(decl)
-                }))
-            }
-            TyKind::Never => node,
-            TyKind::Tup(tys) => TyKind::Tup(tys.move_map(|ty| fld.fold_ty(ty))),
-            TyKind::Paren(ty) => TyKind::Paren(fld.fold_ty(ty)),
-            TyKind::Path(qself, path) => {
-                let (qself, path) = fld.fold_qpath(qself, path);
-                TyKind::Path(qself, path)
-            }
-            TyKind::Array(ty, length) => {
-                TyKind::Array(fld.fold_ty(ty), fld.fold_anon_const(length))
-            }
-            TyKind::Typeof(expr) => {
-                TyKind::Typeof(fld.fold_anon_const(expr))
-            }
-            TyKind::TraitObject(bounds, syntax) => {
-                TyKind::TraitObject(bounds.move_map(|b| fld.fold_param_bound(b)), syntax)
-            }
-            TyKind::ImplTrait(id, bounds) => {
-                TyKind::ImplTrait(fld.new_id(id), bounds.move_map(|b| fld.fold_param_bound(b)))
-            }
-            TyKind::Mac(mac) => {
-                TyKind::Mac(fld.fold_mac(mac))
-            }
-        },
-        span: fld.new_span(span)
-    })
-}
-
-pub fn noop_fold_foreign_mod<T: Folder>(ForeignMod {abi, items}: ForeignMod,
-                                        fld: &mut T) -> ForeignMod {
-    ForeignMod {
-        abi,
-        items: items.move_flat_map(|x| fld.fold_foreign_item(x)),
-    }
-}
-
-pub fn noop_fold_global_asm<T: Folder>(ga: P<GlobalAsm>,
-                                       _: &mut T) -> P<GlobalAsm> {
-    ga
-}
-
-pub fn noop_fold_variant<T: Folder>(v: Variant, fld: &mut T) -> Variant {
-    Spanned {
-        node: Variant_ {
-            ident: fld.fold_ident(v.node.ident),
-            attrs: fold_attrs(v.node.attrs, fld),
-            data: fld.fold_variant_data(v.node.data),
-            disr_expr: v.node.disr_expr.map(|e| fld.fold_anon_const(e)),
-        },
-        span: fld.new_span(v.span),
-    }
-}
-
-pub fn noop_fold_ident<T: Folder>(ident: Ident, fld: &mut T) -> Ident {
-    Ident::new(ident.name, fld.new_span(ident.span))
-}
-
-pub fn noop_fold_usize<T: Folder>(i: usize, _: &mut T) -> usize {
-    i
-}
-
-pub fn noop_fold_path<T: Folder>(Path { segments, span }: Path, fld: &mut T) -> Path {
-    Path {
-        segments: segments.move_map(|PathSegment { ident, id, args }| PathSegment {
-            ident: fld.fold_ident(ident),
-            id: fld.new_id(id),
-            args: args.map(|args| args.map(|args| fld.fold_generic_args(args))),
-        }),
-        span: fld.new_span(span)
-    }
-}
-
-pub fn noop_fold_qpath<T: Folder>(qself: Option<QSelf>,
-                                  path: Path,
-                                  fld: &mut T) -> (Option<QSelf>, Path) {
-    let qself = qself.map(|QSelf { ty, path_span, position }| {
-        QSelf {
-            ty: fld.fold_ty(ty),
-            path_span: fld.new_span(path_span),
-            position,
-        }
-    });
-    (qself, fld.fold_path(path))
-}
-
-pub fn noop_fold_generic_args<T: Folder>(generic_args: GenericArgs, fld: &mut T) -> GenericArgs
-{
-    match generic_args {
-        GenericArgs::AngleBracketed(data) => {
-            GenericArgs::AngleBracketed(fld.fold_angle_bracketed_parameter_data(data))
-        }
-        GenericArgs::Parenthesized(data) => {
-            GenericArgs::Parenthesized(fld.fold_parenthesized_parameter_data(data))
-        }
-    }
-}
-
-pub fn noop_fold_angle_bracketed_parameter_data<T: Folder>(data: AngleBracketedArgs,
-                                                           fld: &mut T)
-                                                           -> AngleBracketedArgs
-{
-    let AngleBracketedArgs { args, bindings, span } = data;
-    AngleBracketedArgs {
-        args: args.move_map(|arg| fld.fold_generic_arg(arg)),
-        bindings: bindings.move_map(|b| fld.fold_ty_binding(b)),
-        span: fld.new_span(span)
-    }
-}
-
-pub fn noop_fold_parenthesized_parameter_data<T: Folder>(data: ParenthesisedArgs,
-                                                         fld: &mut T)
-                                                         -> ParenthesisedArgs
-{
-    let ParenthesisedArgs { inputs, output, span } = data;
-    ParenthesisedArgs {
-        inputs: inputs.move_map(|ty| fld.fold_ty(ty)),
-        output: output.map(|ty| fld.fold_ty(ty)),
-        span: fld.new_span(span)
-    }
-}
-
-pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
-    l.map(|Local {id, pat, ty, init, span, attrs}| Local {
-        id: fld.new_id(id),
-        pat: fld.fold_pat(pat),
-        ty: ty.map(|t| fld.fold_ty(t)),
-        init: init.map(|e| fld.fold_expr(e)),
-        span: fld.new_span(span),
-        attrs: fold_attrs(attrs.into(), fld).into(),
-    })
-}
-
-pub fn noop_fold_attribute<T: Folder>(attr: Attribute, fld: &mut T) -> Option<Attribute> {
-    Some(Attribute {
-        id: attr.id,
-        style: attr.style,
-        path: fld.fold_path(attr.path),
-        tokens: fld.fold_tts(attr.tokens),
-        is_sugared_doc: attr.is_sugared_doc,
-        span: fld.new_span(attr.span),
-    })
-}
-
-pub fn noop_fold_mac<T: Folder>(Spanned {node, span}: Mac, fld: &mut T) -> Mac {
-    Spanned {
-        node: Mac_ {
-            tts: fld.fold_tts(node.stream()).into(),
-            path: fld.fold_path(node.path),
-            delim: node.delim,
-        },
-        span: fld.new_span(span)
-    }
-}
-
-pub fn noop_fold_macro_def<T: Folder>(def: MacroDef, fld: &mut T) -> MacroDef {
-    MacroDef {
-        tokens: fld.fold_tts(def.tokens.into()).into(),
-        legacy: def.legacy,
-    }
-}
-
-pub fn noop_fold_meta_list_item<T: Folder>(li: NestedMetaItem, fld: &mut T)
-    -> NestedMetaItem {
-    Spanned {
-        node: match li.node {
-            NestedMetaItemKind::MetaItem(mi) =>  {
-                NestedMetaItemKind::MetaItem(fld.fold_meta_item(mi))
-            },
-            NestedMetaItemKind::Literal(lit) => NestedMetaItemKind::Literal(lit)
-        },
-        span: fld.new_span(li.span)
-    }
-}
-
-pub fn noop_fold_meta_item<T: Folder>(mi: MetaItem, fld: &mut T) -> MetaItem {
-    MetaItem {
-        ident: mi.ident,
-        node: match mi.node {
-            MetaItemKind::Word => MetaItemKind::Word,
-            MetaItemKind::List(mis) => {
-                MetaItemKind::List(mis.move_map(|e| fld.fold_meta_list_item(e)))
-            },
-            MetaItemKind::NameValue(s) => MetaItemKind::NameValue(s),
-        },
-        span: fld.new_span(mi.span)
-    }
-}
-
-pub fn noop_fold_arg<T: Folder>(Arg {id, pat, ty}: Arg, fld: &mut T) -> Arg {
-    Arg {
-        id: fld.new_id(id),
-        pat: fld.fold_pat(pat),
-        ty: fld.fold_ty(ty)
-    }
-}
-
-pub fn noop_fold_tt<T: Folder>(tt: TokenTree, fld: &mut T) -> TokenTree {
-    match tt {
-        TokenTree::Token(span, tok) =>
-            TokenTree::Token(fld.new_span(span), fld.fold_token(tok)),
-        TokenTree::Delimited(span, delim, tts) => TokenTree::Delimited(
-            DelimSpan::from_pair(fld.new_span(span.open), fld.new_span(span.close)),
-            delim,
-            fld.fold_tts(tts.stream()).into(),
-        ),
-    }
-}
-
-pub fn noop_fold_tts<T: Folder>(tts: TokenStream, fld: &mut T) -> TokenStream {
-    tts.map(|tt| fld.fold_tt(tt))
-}
-
-// apply ident folder if it's an ident, apply other folds to interpolated nodes
-pub fn noop_fold_token<T: Folder>(t: token::Token, fld: &mut T) -> token::Token {
-    match t {
-        token::Ident(id, is_raw) => token::Ident(fld.fold_ident(id), is_raw),
-        token::Lifetime(id) => token::Lifetime(fld.fold_ident(id)),
-        token::Interpolated(nt) => {
-            let nt = match Lrc::try_unwrap(nt) {
-                Ok(nt) => nt,
-                Err(nt) => (*nt).clone(),
-            };
-            Token::interpolated(fld.fold_interpolated(nt.0))
-        }
-        _ => t
-    }
-}
-
-/// apply folder to elements of interpolated nodes
-//
-// N.B., this can occur only when applying a fold to partially expanded code, where
-// parsed pieces have gotten implanted ito *other* macro invocations. This is relevant
-// for macro hygiene, but possibly not elsewhere.
-//
-// One problem here occurs because the types for fold_item, fold_stmt, etc. allow the
-// folder to return *multiple* items; this is a problem for the nodes here, because
-// they insist on having exactly one piece. One solution would be to mangle the fold
-// trait to include one-to-many and one-to-one versions of these entry points, but that
-// would probably confuse a lot of people and help very few. Instead, I'm just going
-// to put in dynamic checks. I think the performance impact of this will be pretty much
-// nonexistent. The danger is that someone will apply a fold to a partially expanded
-// node, and will be confused by the fact that their "fold_item" or "fold_stmt" isn't
-// getting called on NtItem or NtStmt nodes. Hopefully they'll wind up reading this
-// comment, and doing something appropriate.
-//
-// BTW, design choice: I considered just changing the type of, e.g., NtItem to contain
-// multiple items, but decided against it when I looked at parse_item_or_view_item and
-// tried to figure out what I would do with multiple items there....
-pub fn noop_fold_interpolated<T: Folder>(nt: token::Nonterminal, fld: &mut T)
-                                         -> token::Nonterminal {
-    match nt {
-        token::NtItem(item) =>
-            token::NtItem(fld.fold_item(item)
-                          // this is probably okay, because the only folds likely
-                          // to peek inside interpolated nodes will be renamings/markings,
-                          // which map single items to single items
-                          .expect_one("expected fold to produce exactly one item")),
-        token::NtBlock(block) => token::NtBlock(fld.fold_block(block)),
-        token::NtStmt(stmt) =>
-            token::NtStmt(fld.fold_stmt(stmt)
-                          // this is probably okay, because the only folds likely
-                          // to peek inside interpolated nodes will be renamings/markings,
-                          // which map single items to single items
-                          .expect_one("expected fold to produce exactly one statement")),
-        token::NtPat(pat) => token::NtPat(fld.fold_pat(pat)),
-        token::NtExpr(expr) => token::NtExpr(fld.fold_expr(expr)),
-        token::NtTy(ty) => token::NtTy(fld.fold_ty(ty)),
-        token::NtIdent(ident, is_raw) => token::NtIdent(fld.fold_ident(ident), is_raw),
-        token::NtLifetime(ident) => token::NtLifetime(fld.fold_ident(ident)),
-        token::NtLiteral(expr) => token::NtLiteral(fld.fold_expr(expr)),
-        token::NtMeta(meta) => token::NtMeta(fld.fold_meta_item(meta)),
-        token::NtPath(path) => token::NtPath(fld.fold_path(path)),
-        token::NtTT(tt) => token::NtTT(fld.fold_tt(tt)),
-        token::NtArm(arm) => token::NtArm(fld.fold_arm(arm)),
-        token::NtImplItem(item) =>
-            token::NtImplItem(fld.fold_impl_item(item)
-                              .expect_one("expected fold to produce exactly one item")),
-        token::NtTraitItem(item) =>
-            token::NtTraitItem(fld.fold_trait_item(item)
-                               .expect_one("expected fold to produce exactly one item")),
-        token::NtGenerics(generics) => token::NtGenerics(fld.fold_generics(generics)),
-        token::NtWhereClause(where_clause) =>
-            token::NtWhereClause(fld.fold_where_clause(where_clause)),
-        token::NtArg(arg) => token::NtArg(fld.fold_arg(arg)),
-        token::NtVis(vis) => token::NtVis(fld.fold_vis(vis)),
-        token::NtForeignItem(ni) =>
-            token::NtForeignItem(fld.fold_foreign_item(ni)
-                                 // see reasoning above
-                                 .expect_one("expected fold to produce exactly one item")),
-    }
-}
-
-pub fn noop_fold_asyncness<T: Folder>(asyncness: IsAsync, fld: &mut T) -> IsAsync {
-    match asyncness {
-        IsAsync::Async { closure_id, return_impl_trait_id } => IsAsync::Async {
-            closure_id: fld.new_id(closure_id),
-            return_impl_trait_id: fld.new_id(return_impl_trait_id),
-        },
-        IsAsync::NotAsync => IsAsync::NotAsync,
-    }
-}
-
-pub fn noop_fold_fn_decl<T: Folder>(decl: P<FnDecl>, fld: &mut T) -> P<FnDecl> {
-    decl.map(|FnDecl {inputs, output, variadic}| FnDecl {
-        inputs: inputs.move_map(|x| fld.fold_arg(x)),
-        output: match output {
-            FunctionRetTy::Ty(ty) => FunctionRetTy::Ty(fld.fold_ty(ty)),
-            FunctionRetTy::Default(span) => FunctionRetTy::Default(fld.new_span(span)),
-        },
-        variadic,
-    })
-}
-
-pub fn noop_fold_param_bound<T>(pb: GenericBound, fld: &mut T) -> GenericBound where T: Folder {
-    match pb {
-        GenericBound::Trait(ty, modifier) => {
-            GenericBound::Trait(fld.fold_poly_trait_ref(ty), modifier)
-        }
-        GenericBound::Outlives(lifetime) => {
-            GenericBound::Outlives(noop_fold_lifetime(lifetime, fld))
-        }
-    }
-}
-
-pub fn noop_fold_generic_param<T: Folder>(param: GenericParam, fld: &mut T) -> GenericParam {
-    let attrs: Vec<_> = param.attrs.into();
-    GenericParam {
-        ident: fld.fold_ident(param.ident),
-        id: fld.new_id(param.id),
-        attrs: attrs.into_iter()
-                    .flat_map(|x| fld.fold_attribute(x).into_iter())
-                    .collect::<Vec<_>>()
-                    .into(),
-        bounds: param.bounds.move_map(|l| noop_fold_param_bound(l, fld)),
-        kind: match param.kind {
-            GenericParamKind::Lifetime => GenericParamKind::Lifetime,
-            GenericParamKind::Type { default } => GenericParamKind::Type {
-                default: default.map(|ty| fld.fold_ty(ty))
-            }
-        }
-    }
-}
-
-pub fn noop_fold_generic_params<T: Folder>(
-    params: Vec<GenericParam>,
-    fld: &mut T
-) -> Vec<GenericParam> {
-    params.move_map(|p| fld.fold_generic_param(p))
-}
-
-pub fn noop_fold_label<T: Folder>(label: Label, fld: &mut T) -> Label {
-    Label {
-        ident: fld.fold_ident(label.ident),
-    }
-}
-
-fn noop_fold_lifetime<T: Folder>(l: Lifetime, fld: &mut T) -> Lifetime {
-    Lifetime {
-        id: fld.new_id(l.id),
-        ident: fld.fold_ident(l.ident),
-    }
-}
-
-pub fn noop_fold_generics<T: Folder>(Generics { params, where_clause, span }: Generics,
-                                     fld: &mut T) -> Generics {
-    Generics {
-        params: fld.fold_generic_params(params),
-        where_clause: fld.fold_where_clause(where_clause),
-        span: fld.new_span(span),
-    }
-}
-
-pub fn noop_fold_where_clause<T: Folder>(
-                              WhereClause {id, predicates, span}: WhereClause,
-                              fld: &mut T)
-                              -> WhereClause {
-    WhereClause {
-        id: fld.new_id(id),
-        predicates: predicates.move_map(|predicate| {
-            fld.fold_where_predicate(predicate)
-        }),
-        span,
-    }
-}
-
-pub fn noop_fold_where_predicate<T: Folder>(
-                                 pred: WherePredicate,
-                                 fld: &mut T)
-                                 -> WherePredicate {
-    match pred {
-        ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate{bound_generic_params,
-                                                                     bounded_ty,
-                                                                     bounds,
-                                                                     span}) => {
-            ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
-                bound_generic_params: fld.fold_generic_params(bound_generic_params),
-                bounded_ty: fld.fold_ty(bounded_ty),
-                bounds: bounds.move_map(|x| fld.fold_param_bound(x)),
-                span: fld.new_span(span)
-            })
-        }
-        ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate{lifetime,
-                                                                       bounds,
-                                                                       span}) => {
-            ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
-                span: fld.new_span(span),
-                lifetime: noop_fold_lifetime(lifetime, fld),
-                bounds: bounds.move_map(|bound| noop_fold_param_bound(bound, fld))
-            })
-        }
-        ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{id,
-                                                               lhs_ty,
-                                                               rhs_ty,
-                                                               span}) => {
-            ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{
-                id: fld.new_id(id),
-                lhs_ty: fld.fold_ty(lhs_ty),
-                rhs_ty: fld.fold_ty(rhs_ty),
-                span: fld.new_span(span)
-            })
-        }
-    }
-}
-
-pub fn noop_fold_variant_data<T: Folder>(vdata: VariantData, fld: &mut T) -> VariantData {
-    match vdata {
-        ast::VariantData::Struct(fields, id) => {
-            ast::VariantData::Struct(fields.move_map(|f| fld.fold_struct_field(f)),
-                                     fld.new_id(id))
-        }
-        ast::VariantData::Tuple(fields, id) => {
-            ast::VariantData::Tuple(fields.move_map(|f| fld.fold_struct_field(f)),
-                                    fld.new_id(id))
-        }
-        ast::VariantData::Unit(id) => ast::VariantData::Unit(fld.new_id(id))
-    }
-}
-
-pub fn noop_fold_trait_ref<T: Folder>(p: TraitRef, fld: &mut T) -> TraitRef {
-    let id = fld.new_id(p.ref_id);
-    let TraitRef {
-        path,
-        ref_id: _,
-    } = p;
-    ast::TraitRef {
-        path: fld.fold_path(path),
-        ref_id: id,
-    }
-}
-
-pub fn noop_fold_poly_trait_ref<T: Folder>(p: PolyTraitRef, fld: &mut T) -> PolyTraitRef {
-    ast::PolyTraitRef {
-        bound_generic_params: fld.fold_generic_params(p.bound_generic_params),
-        trait_ref: fld.fold_trait_ref(p.trait_ref),
-        span: fld.new_span(p.span),
-    }
-}
-
-pub fn noop_fold_struct_field<T: Folder>(f: StructField, fld: &mut T) -> StructField {
-    StructField {
-        span: fld.new_span(f.span),
-        id: fld.new_id(f.id),
-        ident: f.ident.map(|ident| fld.fold_ident(ident)),
-        vis: fld.fold_vis(f.vis),
-        ty: fld.fold_ty(f.ty),
-        attrs: fold_attrs(f.attrs, fld),
-    }
-}
-
-pub fn noop_fold_field<T: Folder>(f: Field, folder: &mut T) -> Field {
-    Field {
-        ident: folder.fold_ident(f.ident),
-        expr: folder.fold_expr(f.expr),
-        span: folder.new_span(f.span),
-        is_shorthand: f.is_shorthand,
-        attrs: fold_thin_attrs(f.attrs, folder),
-    }
-}
-
-pub fn noop_fold_mt<T: Folder>(MutTy {ty, mutbl}: MutTy, folder: &mut T) -> MutTy {
-    MutTy {
-        ty: folder.fold_ty(ty),
-        mutbl,
-    }
-}
-
-pub fn noop_fold_opt_bounds<T: Folder>(b: Option<GenericBounds>, folder: &mut T)
-                                       -> Option<GenericBounds> {
-    b.map(|bounds| folder.fold_bounds(bounds))
-}
-
-fn noop_fold_bounds<T: Folder>(bounds: GenericBounds, folder: &mut T)
-                          -> GenericBounds {
-    bounds.move_map(|bound| folder.fold_param_bound(bound))
-}
-
-pub fn noop_fold_block<T: Folder>(b: P<Block>, folder: &mut T) -> P<Block> {
-    b.map(|Block {id, stmts, rules, span}| Block {
-        id: folder.new_id(id),
-        stmts: stmts.move_flat_map(|s| folder.fold_stmt(s).into_iter()),
-        rules,
-        span: folder.new_span(span),
-    })
-}
-
-pub fn noop_fold_item_kind<T: Folder>(i: ItemKind, folder: &mut T) -> ItemKind {
-    match i {
-        ItemKind::ExternCrate(orig_name) => ItemKind::ExternCrate(orig_name),
-        ItemKind::Use(use_tree) => {
-            ItemKind::Use(use_tree.map(|tree| folder.fold_use_tree(tree)))
-        }
-        ItemKind::Static(t, m, e) => {
-            ItemKind::Static(folder.fold_ty(t), m, folder.fold_expr(e))
-        }
-        ItemKind::Const(t, e) => {
-            ItemKind::Const(folder.fold_ty(t), folder.fold_expr(e))
-        }
-        ItemKind::Fn(decl, header, generics, body) => {
-            let generics = folder.fold_generics(generics);
-            let header = folder.fold_fn_header(header);
-            let decl = folder.fold_fn_decl(decl);
-            let body = folder.fold_block(body);
-            ItemKind::Fn(decl, header, generics, body)
-        }
-        ItemKind::Mod(m) => ItemKind::Mod(folder.fold_mod(m)),
-        ItemKind::ForeignMod(nm) => ItemKind::ForeignMod(folder.fold_foreign_mod(nm)),
-        ItemKind::GlobalAsm(ga) => ItemKind::GlobalAsm(folder.fold_global_asm(ga)),
-        ItemKind::Ty(t, generics) => {
-            ItemKind::Ty(folder.fold_ty(t), folder.fold_generics(generics))
-        }
-        ItemKind::Existential(bounds, generics) => ItemKind::Existential(
-            folder.fold_bounds(bounds),
-            folder.fold_generics(generics),
-        ),
-        ItemKind::Enum(enum_definition, generics) => {
-            let generics = folder.fold_generics(generics);
-            let variants = enum_definition.variants.move_map(|x| folder.fold_variant(x));
-            ItemKind::Enum(ast::EnumDef { variants }, generics)
-        }
-        ItemKind::Struct(struct_def, generics) => {
-            let generics = folder.fold_generics(generics);
-            ItemKind::Struct(folder.fold_variant_data(struct_def), generics)
-        }
-        ItemKind::Union(struct_def, generics) => {
-            let generics = folder.fold_generics(generics);
-            ItemKind::Union(folder.fold_variant_data(struct_def), generics)
-        }
-        ItemKind::Impl(unsafety,
-                       polarity,
-                       defaultness,
-                       generics,
-                       ifce,
-                       ty,
-                       impl_items) => ItemKind::Impl(
-            unsafety,
-            polarity,
-            defaultness,
-            folder.fold_generics(generics),
-            ifce.map(|trait_ref| folder.fold_trait_ref(trait_ref)),
-            folder.fold_ty(ty),
-            impl_items.move_flat_map(|item| folder.fold_impl_item(item)),
-        ),
-        ItemKind::Trait(is_auto, unsafety, generics, bounds, items) => ItemKind::Trait(
-            is_auto,
-            unsafety,
-            folder.fold_generics(generics),
-            folder.fold_bounds(bounds),
-            items.move_flat_map(|item| folder.fold_trait_item(item)),
-        ),
-        ItemKind::TraitAlias(generics, bounds) => ItemKind::TraitAlias(
-            folder.fold_generics(generics),
-            folder.fold_bounds(bounds)),
-        ItemKind::Mac(m) => ItemKind::Mac(folder.fold_mac(m)),
-        ItemKind::MacroDef(def) => ItemKind::MacroDef(folder.fold_macro_def(def)),
-    }
-}
-
-pub fn noop_fold_trait_item<T: Folder>(i: TraitItem, folder: &mut T) -> SmallVec<[TraitItem; 1]> {
-    smallvec![TraitItem {
-        id: folder.new_id(i.id),
-        ident: folder.fold_ident(i.ident),
-        attrs: fold_attrs(i.attrs, folder),
-        generics: folder.fold_generics(i.generics),
-        node: match i.node {
-            TraitItemKind::Const(ty, default) => {
-                TraitItemKind::Const(folder.fold_ty(ty),
-                               default.map(|x| folder.fold_expr(x)))
-            }
-            TraitItemKind::Method(sig, body) => {
-                TraitItemKind::Method(noop_fold_method_sig(sig, folder),
-                                body.map(|x| folder.fold_block(x)))
-            }
-            TraitItemKind::Type(bounds, default) => {
-                TraitItemKind::Type(folder.fold_bounds(bounds),
-                              default.map(|x| folder.fold_ty(x)))
-            }
-            ast::TraitItemKind::Macro(mac) => {
-                TraitItemKind::Macro(folder.fold_mac(mac))
-            }
-        },
-        span: folder.new_span(i.span),
-        tokens: i.tokens,
-    }]
-}
-
-pub fn noop_fold_impl_item<T: Folder>(i: ImplItem, folder: &mut T)-> SmallVec<[ImplItem; 1]> {
-    smallvec![ImplItem {
-        id: folder.new_id(i.id),
-        vis: folder.fold_vis(i.vis),
-        ident: folder.fold_ident(i.ident),
-        attrs: fold_attrs(i.attrs, folder),
-        generics: folder.fold_generics(i.generics),
-        defaultness: i.defaultness,
-        node: match i.node  {
-            ast::ImplItemKind::Const(ty, expr) => {
-                ast::ImplItemKind::Const(folder.fold_ty(ty), folder.fold_expr(expr))
-            }
-            ast::ImplItemKind::Method(sig, body) => {
-                ast::ImplItemKind::Method(noop_fold_method_sig(sig, folder),
-                               folder.fold_block(body))
-            }
-            ast::ImplItemKind::Type(ty) => ast::ImplItemKind::Type(folder.fold_ty(ty)),
-            ast::ImplItemKind::Existential(bounds) => {
-                ast::ImplItemKind::Existential(folder.fold_bounds(bounds))
-            },
-            ast::ImplItemKind::Macro(mac) => ast::ImplItemKind::Macro(folder.fold_mac(mac))
-        },
-        span: folder.new_span(i.span),
-        tokens: i.tokens,
-    }]
-}
-
-pub fn noop_fold_fn_header<T: Folder>(mut header: FnHeader, folder: &mut T) -> FnHeader {
-    header.asyncness = folder.fold_asyncness(header.asyncness);
-    header
-}
-
-pub fn noop_fold_mod<T: Folder>(Mod {inner, items, inline}: Mod, folder: &mut T) -> Mod {
-    Mod {
-        inner: folder.new_span(inner),
-        items: items.move_flat_map(|x| folder.fold_item(x)),
-        inline: inline,
-    }
-}
-
-pub fn noop_fold_crate<T: Folder>(Crate {module, attrs, span}: Crate,
-                                  folder: &mut T) -> Crate {
-    let mut items = folder.fold_item(P(ast::Item {
-        ident: keywords::Invalid.ident(),
-        attrs,
-        id: ast::DUMMY_NODE_ID,
-        vis: respan(span.shrink_to_lo(), ast::VisibilityKind::Public),
-        span,
-        node: ast::ItemKind::Mod(module),
-        tokens: None,
-    })).into_iter();
-
-    let (module, attrs, span) = match items.next() {
-        Some(item) => {
-            assert!(items.next().is_none(),
-                    "a crate cannot expand to more than one item");
-            item.and_then(|ast::Item { attrs, span, node, .. }| {
-                match node {
-                    ast::ItemKind::Mod(m) => (m, attrs, span),
-                    _ => panic!("fold converted a module to not a module"),
-                }
-            })
-        }
-        None => (ast::Mod {
-            inner: span,
-            items: vec![],
-            inline: true,
-        }, vec![], span)
-    };
-
-    Crate {
-        module,
-        attrs,
-        span,
-    }
-}
-
-// fold one item into possibly many items
-pub fn noop_fold_item<T: Folder>(i: P<Item>, folder: &mut T) -> SmallVec<[P<Item>; 1]> {
-    smallvec![i.map(|i| folder.fold_item_simple(i))]
-}
-
-// fold one item into exactly one item
-pub fn noop_fold_item_simple<T: Folder>(Item {id, ident, attrs, node, vis, span, tokens}: Item,
-                                        folder: &mut T) -> Item {
-    Item {
-        id: folder.new_id(id),
-        vis: folder.fold_vis(vis),
-        ident: folder.fold_ident(ident),
-        attrs: fold_attrs(attrs, folder),
-        node: folder.fold_item_kind(node),
-        span: folder.new_span(span),
-
-        // FIXME: if this is replaced with a call to `folder.fold_tts` it causes
-        //        an ICE during resolve... odd!
-        tokens,
-    }
-}
-
-pub fn noop_fold_foreign_item<T: Folder>(ni: ForeignItem, folder: &mut T)
-    -> SmallVec<[ForeignItem; 1]>
-{
-    smallvec![folder.fold_foreign_item_simple(ni)]
-}
-
-pub fn noop_fold_foreign_item_simple<T: Folder>(ni: ForeignItem, folder: &mut T) -> ForeignItem {
-    ForeignItem {
-        id: folder.new_id(ni.id),
-        vis: folder.fold_vis(ni.vis),
-        ident: folder.fold_ident(ni.ident),
-        attrs: fold_attrs(ni.attrs, folder),
-        node: match ni.node {
-            ForeignItemKind::Fn(fdec, generics) => {
-                ForeignItemKind::Fn(folder.fold_fn_decl(fdec), folder.fold_generics(generics))
-            }
-            ForeignItemKind::Static(t, m) => {
-                ForeignItemKind::Static(folder.fold_ty(t), m)
-            }
-            ForeignItemKind::Ty => ForeignItemKind::Ty,
-            ForeignItemKind::Macro(mac) => ForeignItemKind::Macro(folder.fold_mac(mac)),
-        },
-        span: folder.new_span(ni.span)
-    }
-}
-
-pub fn noop_fold_method_sig<T: Folder>(sig: MethodSig, folder: &mut T) -> MethodSig {
-    MethodSig {
-        header: folder.fold_fn_header(sig.header),
-        decl: folder.fold_fn_decl(sig.decl)
-    }
-}
-
-pub fn noop_fold_pat<T: Folder>(p: P<Pat>, folder: &mut T) -> P<Pat> {
-    p.map(|Pat {id, node, span}| Pat {
-        id: folder.new_id(id),
-        node: match node {
-            PatKind::Wild => PatKind::Wild,
-            PatKind::Ident(binding_mode, ident, sub) => {
-                PatKind::Ident(binding_mode,
-                               folder.fold_ident(ident),
-                               sub.map(|x| folder.fold_pat(x)))
-            }
-            PatKind::Lit(e) => PatKind::Lit(folder.fold_expr(e)),
-            PatKind::TupleStruct(pth, pats, ddpos) => {
-                PatKind::TupleStruct(folder.fold_path(pth),
-                        pats.move_map(|x| folder.fold_pat(x)), ddpos)
-            }
-            PatKind::Path(qself, pth) => {
-                let (qself, pth) = folder.fold_qpath(qself, pth);
-                PatKind::Path(qself, pth)
-            }
-            PatKind::Struct(pth, fields, etc) => {
-                let pth = folder.fold_path(pth);
-                let fs = fields.move_map(|f| {
-                    Spanned { span: folder.new_span(f.span),
-                              node: ast::FieldPat {
-                                  ident: folder.fold_ident(f.node.ident),
-                                  pat: folder.fold_pat(f.node.pat),
-                                  is_shorthand: f.node.is_shorthand,
-                                  attrs: fold_attrs(f.node.attrs.into(), folder).into()
-                              }}
-                });
-                PatKind::Struct(pth, fs, etc)
-            }
-            PatKind::Tuple(elts, ddpos) => {
-                PatKind::Tuple(elts.move_map(|x| folder.fold_pat(x)), ddpos)
-            }
-            PatKind::Box(inner) => PatKind::Box(folder.fold_pat(inner)),
-            PatKind::Ref(inner, mutbl) => PatKind::Ref(folder.fold_pat(inner), mutbl),
-            PatKind::Range(e1, e2, Spanned { span, node: end }) => {
-                PatKind::Range(folder.fold_expr(e1),
-                               folder.fold_expr(e2),
-                               Spanned { span, node: folder.fold_range_end(end) })
-            },
-            PatKind::Slice(before, slice, after) => {
-                PatKind::Slice(before.move_map(|x| folder.fold_pat(x)),
-                       slice.map(|x| folder.fold_pat(x)),
-                       after.move_map(|x| folder.fold_pat(x)))
-            }
-            PatKind::Paren(inner) => PatKind::Paren(folder.fold_pat(inner)),
-            PatKind::Mac(mac) => PatKind::Mac(folder.fold_mac(mac))
-        },
-        span: folder.new_span(span)
-    })
-}
-
-pub fn noop_fold_range_end<T: Folder>(end: RangeEnd, _folder: &mut T) -> RangeEnd {
-    end
-}
-
-pub fn noop_fold_anon_const<T: Folder>(constant: AnonConst, folder: &mut T) -> AnonConst {
-    let AnonConst {id, value} = constant;
-    AnonConst {
-        id: folder.new_id(id),
-        value: folder.fold_expr(value),
-    }
-}
-
-pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mut T) -> Expr {
-    Expr {
-        node: match node {
-            ExprKind::Box(e) => {
-                ExprKind::Box(folder.fold_expr(e))
-            }
-            ExprKind::ObsoleteInPlace(a, b) => {
-                ExprKind::ObsoleteInPlace(folder.fold_expr(a), folder.fold_expr(b))
-            }
-            ExprKind::Array(exprs) => {
-                ExprKind::Array(folder.fold_exprs(exprs))
-            }
-            ExprKind::Repeat(expr, count) => {
-                ExprKind::Repeat(folder.fold_expr(expr), folder.fold_anon_const(count))
-            }
-            ExprKind::Tup(exprs) => ExprKind::Tup(folder.fold_exprs(exprs)),
-            ExprKind::Call(f, args) => {
-                ExprKind::Call(folder.fold_expr(f),
-                         folder.fold_exprs(args))
-            }
-            ExprKind::MethodCall(seg, args) => {
-                ExprKind::MethodCall(
-                    PathSegment {
-                        ident: folder.fold_ident(seg.ident),
-                        id: folder.new_id(seg.id),
-                        args: seg.args.map(|args| {
-                            args.map(|args| folder.fold_generic_args(args))
-                        }),
-                    },
-                    folder.fold_exprs(args))
-            }
-            ExprKind::Binary(binop, lhs, rhs) => {
-                ExprKind::Binary(binop,
-                        folder.fold_expr(lhs),
-                        folder.fold_expr(rhs))
-            }
-            ExprKind::Unary(binop, ohs) => {
-                ExprKind::Unary(binop, folder.fold_expr(ohs))
-            }
-            ExprKind::Lit(l) => ExprKind::Lit(l),
-            ExprKind::Cast(expr, ty) => {
-                ExprKind::Cast(folder.fold_expr(expr), folder.fold_ty(ty))
-            }
-            ExprKind::Type(expr, ty) => {
-                ExprKind::Type(folder.fold_expr(expr), folder.fold_ty(ty))
-            }
-            ExprKind::AddrOf(m, ohs) => ExprKind::AddrOf(m, folder.fold_expr(ohs)),
-            ExprKind::If(cond, tr, fl) => {
-                ExprKind::If(folder.fold_expr(cond),
-                       folder.fold_block(tr),
-                       fl.map(|x| folder.fold_expr(x)))
-            }
-            ExprKind::IfLet(pats, expr, tr, fl) => {
-                ExprKind::IfLet(pats.move_map(|pat| folder.fold_pat(pat)),
-                          folder.fold_expr(expr),
-                          folder.fold_block(tr),
-                          fl.map(|x| folder.fold_expr(x)))
-            }
-            ExprKind::While(cond, body, opt_label) => {
-                ExprKind::While(folder.fold_expr(cond),
-                          folder.fold_block(body),
-                          opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::WhileLet(pats, expr, body, opt_label) => {
-                ExprKind::WhileLet(pats.move_map(|pat| folder.fold_pat(pat)),
-                             folder.fold_expr(expr),
-                             folder.fold_block(body),
-                             opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::ForLoop(pat, iter, body, opt_label) => {
-                ExprKind::ForLoop(folder.fold_pat(pat),
-                            folder.fold_expr(iter),
-                            folder.fold_block(body),
-                            opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::Loop(body, opt_label) => {
-                ExprKind::Loop(folder.fold_block(body),
-                               opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::Match(expr, arms) => {
-                ExprKind::Match(folder.fold_expr(expr),
-                          arms.move_map(|x| folder.fold_arm(x)))
-            }
-            ExprKind::Closure(capture_clause, asyncness, movability, decl, body, span) => {
-                ExprKind::Closure(capture_clause,
-                                  folder.fold_asyncness(asyncness),
-                                  movability,
-                                  folder.fold_fn_decl(decl),
-                                  folder.fold_expr(body),
-                                  folder.new_span(span))
-            }
-            ExprKind::Block(blk, opt_label) => {
-                ExprKind::Block(folder.fold_block(blk),
-                                opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::Async(capture_clause, node_id, body) => {
-                ExprKind::Async(
-                    capture_clause,
-                    folder.new_id(node_id),
-                    folder.fold_block(body),
-                )
-            }
-            ExprKind::Assign(el, er) => {
-                ExprKind::Assign(folder.fold_expr(el), folder.fold_expr(er))
-            }
-            ExprKind::AssignOp(op, el, er) => {
-                ExprKind::AssignOp(op,
-                            folder.fold_expr(el),
-                            folder.fold_expr(er))
-            }
-            ExprKind::Field(el, ident) => {
-                ExprKind::Field(folder.fold_expr(el), folder.fold_ident(ident))
-            }
-            ExprKind::Index(el, er) => {
-                ExprKind::Index(folder.fold_expr(el), folder.fold_expr(er))
-            }
-            ExprKind::Range(e1, e2, lim) => {
-                ExprKind::Range(e1.map(|x| folder.fold_expr(x)),
-                                e2.map(|x| folder.fold_expr(x)),
-                                lim)
-            }
-            ExprKind::Path(qself, path) => {
-                let (qself, path) = folder.fold_qpath(qself, path);
-                ExprKind::Path(qself, path)
-            }
-            ExprKind::Break(opt_label, opt_expr) => {
-                ExprKind::Break(opt_label.map(|label| folder.fold_label(label)),
-                                opt_expr.map(|e| folder.fold_expr(e)))
-            }
-            ExprKind::Continue(opt_label) => {
-                ExprKind::Continue(opt_label.map(|label| folder.fold_label(label)))
-            }
-            ExprKind::Ret(e) => ExprKind::Ret(e.map(|x| folder.fold_expr(x))),
-            ExprKind::InlineAsm(asm) => ExprKind::InlineAsm(asm.map(|asm| {
-                InlineAsm {
-                    inputs: asm.inputs.move_map(|(c, input)| {
-                        (c, folder.fold_expr(input))
-                    }),
-                    outputs: asm.outputs.move_map(|out| {
-                        InlineAsmOutput {
-                            constraint: out.constraint,
-                            expr: folder.fold_expr(out.expr),
-                            is_rw: out.is_rw,
-                            is_indirect: out.is_indirect,
-                        }
-                    }),
-                    ..asm
-                }
-            })),
-            ExprKind::Mac(mac) => ExprKind::Mac(folder.fold_mac(mac)),
-            ExprKind::Struct(path, fields, maybe_expr) => {
-                ExprKind::Struct(folder.fold_path(path),
-                        fields.move_map(|x| folder.fold_field(x)),
-                        maybe_expr.map(|x| folder.fold_expr(x)))
-            },
-            ExprKind::Paren(ex) => {
-                let sub_expr = folder.fold_expr(ex);
-                return Expr {
-                    // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
-                    id: sub_expr.id,
-                    node: ExprKind::Paren(sub_expr),
-                    span: folder.new_span(span),
-                    attrs: fold_attrs(attrs.into(), folder).into(),
-                };
-            }
-            ExprKind::Yield(ex) => ExprKind::Yield(ex.map(|x| folder.fold_expr(x))),
-            ExprKind::Try(ex) => ExprKind::Try(folder.fold_expr(ex)),
-            ExprKind::TryBlock(body) => ExprKind::TryBlock(folder.fold_block(body)),
-            ExprKind::Err => ExprKind::Err,
-        },
-        id: folder.new_id(id),
-        span: folder.new_span(span),
-        attrs: fold_attrs(attrs.into(), folder).into(),
-    }
-}
-
-pub fn noop_fold_opt_expr<T: Folder>(e: P<Expr>, folder: &mut T) -> Option<P<Expr>> {
-    Some(folder.fold_expr(e))
-}
-
-pub fn noop_fold_exprs<T: Folder>(es: Vec<P<Expr>>, folder: &mut T) -> Vec<P<Expr>> {
-    es.move_flat_map(|e| folder.fold_opt_expr(e))
-}
-
-pub fn noop_fold_stmt<T: Folder>(Stmt {node, span, id}: Stmt, folder: &mut T) -> SmallVec<[Stmt; 1]>
-{
-    let id = folder.new_id(id);
-    let span = folder.new_span(span);
-    noop_fold_stmt_kind(node, folder).into_iter().map(|node| {
-        Stmt { id: id, node: node, span: span }
-    }).collect()
-}
-
-pub fn noop_fold_stmt_kind<T: Folder>(node: StmtKind, folder: &mut T) -> SmallVec<[StmtKind; 1]> {
-    match node {
-        StmtKind::Local(local) => smallvec![StmtKind::Local(folder.fold_local(local))],
-        StmtKind::Item(item) => folder.fold_item(item).into_iter().map(StmtKind::Item).collect(),
-        StmtKind::Expr(expr) => {
-            folder.fold_opt_expr(expr).into_iter().map(StmtKind::Expr).collect()
-        }
-        StmtKind::Semi(expr) => {
-            folder.fold_opt_expr(expr).into_iter().map(StmtKind::Semi).collect()
-        }
-        StmtKind::Mac(mac) => smallvec![StmtKind::Mac(mac.map(|(mac, semi, attrs)| {
-            (folder.fold_mac(mac), semi, fold_attrs(attrs.into(), folder).into())
-        }))],
-    }
-}
-
-pub fn noop_fold_vis<T: Folder>(vis: Visibility, folder: &mut T) -> Visibility {
-    match vis.node {
-        VisibilityKind::Restricted { path, id } => {
-            respan(vis.span, VisibilityKind::Restricted {
-                path: path.map(|path| folder.fold_path(path)),
-                id: folder.new_id(id),
-            })
-        }
-        _ => vis,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use std::io;
-    use ast::{self, Ident};
-    use util::parser_testing::{string_to_crate, matches_codepattern};
-    use print::pprust;
-    use fold;
-    use with_globals;
-    use super::*;
-
-    // this version doesn't care about getting comments or docstrings in.
-    fn fake_print_crate(s: &mut pprust::State,
-                        krate: &ast::Crate) -> io::Result<()> {
-        s.print_mod(&krate.module, &krate.attrs)
-    }
-
-    // change every identifier to "zz"
-    struct ToZzIdentFolder;
-
-    impl Folder for ToZzIdentFolder {
-        fn fold_ident(&mut self, _: ast::Ident) -> ast::Ident {
-            Ident::from_str("zz")
-        }
-        fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
-            fold::noop_fold_mac(mac, self)
-        }
-    }
-
-    // maybe add to expand.rs...
-    macro_rules! assert_pred {
-        ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
-            {
-                let pred_val = $pred;
-                let a_val = $a;
-                let b_val = $b;
-                if !(pred_val(&a_val, &b_val)) {
-                    panic!("expected args satisfying {}, got {} and {}",
-                          $predname, a_val, b_val);
-                }
-            }
-        )
-    }
-
-    // make sure idents get transformed everywhere
-    #[test] fn ident_transformation () {
-        with_globals(|| {
-            let mut zz_fold = ToZzIdentFolder;
-            let ast = string_to_crate(
-                "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
-            let folded_crate = zz_fold.fold_crate(ast);
-            assert_pred!(
-                matches_codepattern,
-                "matches_codepattern",
-                pprust::to_string(|s| fake_print_crate(s, &folded_crate)),
-                "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
-        })
-    }
-
-    // even inside macro defs....
-    #[test] fn ident_transformation_in_defs () {
-        with_globals(|| {
-            let mut zz_fold = ToZzIdentFolder;
-            let ast = string_to_crate(
-                "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
-                (g $(d $d $e)+))} ".to_string());
-            let folded_crate = zz_fold.fold_crate(ast);
-            assert_pred!(
-                matches_codepattern,
-                "matches_codepattern",
-                pprust::to_string(|s| fake_print_crate(s, &folded_crate)),
-                "macro_rules! zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());
-        })
-    }
-}
diff --git a/src/libsyntax/json.rs b/src/libsyntax/json.rs
index cf11ac550b763..9acd0d099a0e1 100644
--- a/src/libsyntax/json.rs
+++ b/src/libsyntax/json.rs
@@ -9,13 +9,14 @@
 
 // FIXME: spec the JSON output properly.
 
-use source_map::{SourceMap, FilePathMapping};
-use syntax_pos::{self, MacroBacktrace, Span, SpanLabel, MultiSpan};
+use crate::source_map::{SourceMap, FilePathMapping};
+
 use errors::registry::Registry;
 use errors::{DiagnosticBuilder, SubDiagnostic, CodeSuggestion, SourceMapper};
 use errors::{DiagnosticId, Applicability};
 use errors::emitter::{Emitter, EmitterWriter};
 
+use syntax_pos::{MacroBacktrace, Span, SpanLabel, MultiSpan};
 use rustc_data_structures::sync::{self, Lrc};
 use std::io::{self, Write};
 use std::vec;
@@ -69,7 +70,7 @@ impl JsonEmitter {
 }
 
 impl Emitter for JsonEmitter {
-    fn emit(&mut self, db: &DiagnosticBuilder) {
+    fn emit(&mut self, db: &DiagnosticBuilder<'_>) {
         let data = Diagnostic::from_diagnostic_builder(db, self);
         let result = if self.pretty {
             writeln!(&mut self.dst, "{}", as_pretty_json(&data))
@@ -159,7 +160,7 @@ struct DiagnosticCode {
 }
 
 impl Diagnostic {
-    fn from_diagnostic_builder(db: &DiagnosticBuilder,
+    fn from_diagnostic_builder(db: &DiagnosticBuilder<'_>,
                                je: &JsonEmitter)
                                -> Diagnostic {
         let sugg = db.suggestions.iter().map(|sugg| {
@@ -342,7 +343,7 @@ impl DiagnosticSpanLine {
         }
     }
 
-    /// Create a list of DiagnosticSpanLines from span - each line with any part
+    /// Creates a list of DiagnosticSpanLines from span - each line with any part
     /// of `span` gets a DiagnosticSpanLine, with the highlight indicating the
     /// `span` within the line.
     fn from_span(span: Span, je: &JsonEmitter) -> Vec<DiagnosticSpanLine> {
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index df22dacce1a75..a6145d5dcb38c 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -4,38 +4,26 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        test(attr(deny(warnings))))]
 
+#![deny(rust_2018_idioms)]
+
 #![feature(crate_visibility_modifier)]
 #![feature(label_break_value)]
 #![feature(nll)]
 #![feature(rustc_attrs)]
 #![feature(rustc_diagnostic_macros)]
-#![feature(slice_sort_by_cached_key)]
-#![feature(str_escape)]
 #![feature(step_trait)]
 #![feature(try_trait)]
 #![feature(unicode_internals)]
 
 #![recursion_limit="256"]
 
-#[macro_use] extern crate bitflags;
-extern crate core;
-extern crate serialize;
-#[macro_use] extern crate log;
-pub extern crate rustc_errors as errors;
-extern crate syntax_pos;
-#[macro_use] extern crate rustc_data_structures;
-extern crate rustc_target;
-#[macro_use] extern crate scoped_tls;
-#[macro_use]
-extern crate smallvec;
-
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
 
+pub use errors;
 use rustc_data_structures::sync::Lock;
 use rustc_data_structures::bit_set::GrowableBitSet;
 pub use rustc_data_structures::thin_vec::ThinVec;
@@ -113,7 +101,7 @@ pub fn with_globals<F, R>(f: F) -> R
     })
 }
 
-scoped_thread_local!(pub static GLOBALS: Globals);
+scoped_tls::scoped_thread_local!(pub static GLOBALS: Globals);
 
 #[macro_use]
 pub mod diagnostics {
@@ -133,15 +121,15 @@ pub mod util {
     pub mod parser;
     #[cfg(test)]
     pub mod parser_testing;
-    pub mod move_map;
+    pub mod map_in_place;
 }
 
 pub mod json;
 
 pub mod syntax {
-    pub use ext;
-    pub use parse;
-    pub use ast;
+    pub use crate::ext;
+    pub use crate::parse;
+    pub use crate::ast;
 }
 
 pub mod ast;
@@ -151,7 +139,7 @@ pub mod source_map;
 pub mod config;
 pub mod entry;
 pub mod feature_gate;
-pub mod fold;
+pub mod mut_visit;
 pub mod parse;
 pub mod ptr;
 pub mod show_span;
@@ -174,7 +162,6 @@ pub mod ext {
     pub mod derive;
     pub mod expand;
     pub mod placeholders;
-    pub mod quote;
     pub mod source_util;
 
     pub mod tt {
diff --git a/src/libsyntax/mut_visit.rs b/src/libsyntax/mut_visit.rs
new file mode 100644
index 0000000000000..fd7003d30a1dc
--- /dev/null
+++ b/src/libsyntax/mut_visit.rs
@@ -0,0 +1,1335 @@
+//! A MutVisitor represents an AST modification; it accepts an AST piece and
+//! and mutates it in place. So, for instance, macro expansion is a MutVisitor
+//! that walks over an AST and modifies it.
+//!
+//! Note: using a MutVisitor (other than the MacroExpander MutVisitor) on
+//! an AST before macro expansion is probably a bad idea. For instance,
+//! a MutVisitor renaming item names in a module will miss all of those
+//! that are created by the expansion of a macro.
+
+use crate::ast::*;
+use crate::source_map::{Spanned, respan};
+use crate::parse::token::{self, Token};
+use crate::ptr::P;
+use crate::symbol::keywords;
+use crate::ThinVec;
+use crate::tokenstream::*;
+use crate::util::map_in_place::MapInPlace;
+
+use smallvec::{smallvec, Array, SmallVec};
+use syntax_pos::Span;
+
+use rustc_data_structures::sync::Lrc;
+use std::ops::DerefMut;
+
+pub trait ExpectOne<A: Array> {
+    fn expect_one(self, err: &'static str) -> A::Item;
+}
+
+impl<A: Array> ExpectOne<A> for SmallVec<A> {
+    fn expect_one(self, err: &'static str) -> A::Item {
+        assert!(self.len() == 1, err);
+        self.into_iter().next().unwrap()
+    }
+}
+
+pub trait MutVisitor: Sized {
+    // Methods in this trait have one of three forms:
+    //
+    //   fn visit_t(&mut self, t: &mut T);                      // common
+    //   fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>;    // rare
+    //   fn filter_map_t(&mut self, t: T) -> Option<T>;         // rarest
+    //
+    // Any additions to this trait should happen in form of a call to a public
+    // `noop_*` function that only calls out to the visitor again, not other
+    // `noop_*` functions. This is a necessary API workaround to the problem of
+    // not being able to call out to the super default method in an overridden
+    // default method.
+    //
+    // When writing these methods, it is better to use destructuring like this:
+    //
+    //   fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
+    //       visit_a(a);
+    //       visit_b(b);
+    //   }
+    //
+    // than to use field access like this:
+    //
+    //   fn visit_abc(&mut self, abc: &mut ABC) {
+    //       visit_a(&mut abc.a);
+    //       visit_b(&mut abc.b);
+    //       // ignore abc.c
+    //   }
+    //
+    // As well as being more concise, the former is explicit about which fields
+    // are skipped. Furthermore, if a new field is added, the destructuring
+    // version will cause a compile error, which is good. In comparison, the
+    // field access version will continue working and it would be easy to
+    // forget to add handling for it.
+
+    fn visit_crate(&mut self, c: &mut Crate) {
+        noop_visit_crate(c, self)
+    }
+
+    fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
+        noop_visit_meta_list_item(list_item, self);
+    }
+
+    fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
+        noop_visit_meta_item(meta_item, self);
+    }
+
+    fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
+        noop_visit_use_tree(use_tree, self);
+    }
+
+    fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
+        noop_flat_map_foreign_item(ni, self)
+    }
+
+    fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
+        noop_flat_map_item(i, self)
+    }
+
+    fn visit_fn_header(&mut self, header: &mut FnHeader) {
+        noop_visit_fn_header(header, self);
+    }
+
+    fn visit_struct_field(&mut self, sf: &mut StructField) {
+        noop_visit_struct_field(sf, self);
+    }
+
+    fn visit_item_kind(&mut self, i: &mut ItemKind) {
+        noop_visit_item_kind(i, self);
+    }
+
+    fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
+        noop_flat_map_trait_item(i, self)
+    }
+
+    fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
+        noop_flat_map_impl_item(i, self)
+    }
+
+    fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
+        noop_visit_fn_decl(d, self);
+    }
+
+    fn visit_asyncness(&mut self, a: &mut IsAsync) {
+        noop_visit_asyncness(a, self);
+    }
+
+    fn visit_block(&mut self, b: &mut P<Block>) {
+        noop_visit_block(b, self);
+    }
+
+    fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
+        noop_flat_map_stmt(s, self)
+    }
+
+    fn visit_arm(&mut self, a: &mut Arm) {
+        noop_visit_arm(a, self);
+    }
+
+    fn visit_guard(&mut self, g: &mut Guard) {
+        noop_visit_guard(g, self);
+    }
+
+    fn visit_pat(&mut self, p: &mut P<Pat>) {
+        noop_visit_pat(p, self);
+    }
+
+    fn visit_anon_const(&mut self, c: &mut AnonConst) {
+        noop_visit_anon_const(c, self);
+    }
+
+    fn visit_expr(&mut self, e: &mut P<Expr>) {
+        noop_visit_expr(e, self);
+    }
+
+    fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
+        noop_filter_map_expr(e, self)
+    }
+
+    fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
+        noop_visit_generic_arg(arg, self);
+    }
+
+    fn visit_ty(&mut self, t: &mut P<Ty>) {
+        noop_visit_ty(t, self);
+    }
+
+    fn visit_lifetime(&mut self, l: &mut Lifetime) {
+        noop_visit_lifetime(l, self);
+    }
+
+    fn visit_ty_binding(&mut self, t: &mut TypeBinding) {
+        noop_visit_ty_binding(t, self);
+    }
+
+    fn visit_mod(&mut self, m: &mut Mod) {
+        noop_visit_mod(m, self);
+    }
+
+    fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
+        noop_visit_foreign_mod(nm, self);
+    }
+
+    fn visit_variant(&mut self, v: &mut Variant) {
+        noop_visit_variant(v, self);
+    }
+
+    fn visit_ident(&mut self, i: &mut Ident) {
+        noop_visit_ident(i, self);
+    }
+
+    fn visit_path(&mut self, p: &mut Path) {
+        noop_visit_path(p, self);
+    }
+
+    fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
+        noop_visit_qself(qs, self);
+    }
+
+    fn visit_generic_args(&mut self, p: &mut GenericArgs) {
+        noop_visit_generic_args(p, self);
+    }
+
+    fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
+        noop_visit_angle_bracketed_parameter_data(p, self);
+    }
+
+    fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
+        noop_visit_parenthesized_parameter_data(p, self);
+    }
+
+    fn visit_local(&mut self, l: &mut P<Local>) {
+        noop_visit_local(l, self);
+    }
+
+    fn visit_mac(&mut self, _mac: &mut Mac) {
+        panic!("visit_mac disabled by default");
+        // N.B., see note about macros above. If you really want a visitor that
+        // works on macros, use this definition in your trait impl:
+        //   mut_visit::noop_visit_mac(_mac, self);
+    }
+
+    fn visit_macro_def(&mut self, def: &mut MacroDef) {
+        noop_visit_macro_def(def, self);
+    }
+
+    fn visit_label(&mut self, label: &mut Label) {
+        noop_visit_label(label, self);
+    }
+
+    fn visit_attribute(&mut self, at: &mut Attribute) {
+        noop_visit_attribute(at, self);
+    }
+
+    fn visit_arg(&mut self, a: &mut Arg) {
+        noop_visit_arg(a, self);
+    }
+
+    fn visit_generics(&mut self, generics: &mut Generics) {
+        noop_visit_generics(generics, self);
+    }
+
+    fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
+        noop_visit_trait_ref(tr, self);
+    }
+
+    fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
+        noop_visit_poly_trait_ref(p, self);
+    }
+
+    fn visit_variant_data(&mut self, vdata: &mut VariantData) {
+        noop_visit_variant_data(vdata, self);
+    }
+
+    fn visit_generic_param(&mut self, param: &mut GenericParam) {
+        noop_visit_generic_param(param, self);
+    }
+
+    fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
+        noop_visit_generic_params(params, self);
+    }
+
+    fn visit_tt(&mut self, tt: &mut TokenTree) {
+        noop_visit_tt(tt, self);
+    }
+
+    fn visit_tts(&mut self, tts: &mut TokenStream) {
+        noop_visit_tts(tts, self);
+    }
+
+    fn visit_token(&mut self, t: &mut Token) {
+        noop_visit_token(t, self);
+    }
+
+    fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
+        noop_visit_interpolated(nt, self);
+    }
+
+    fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
+        noop_visit_param_bound(tpb, self);
+    }
+
+    fn visit_mt(&mut self, mt: &mut MutTy) {
+        noop_visit_mt(mt, self);
+    }
+
+    fn visit_field(&mut self, field: &mut Field) {
+        noop_visit_field(field, self);
+    }
+
+    fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
+        noop_visit_where_clause(where_clause, self);
+    }
+
+    fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
+        noop_visit_where_predicate(where_predicate, self);
+    }
+
+    fn visit_vis(&mut self, vis: &mut Visibility) {
+        noop_visit_vis(vis, self);
+    }
+
+    fn visit_id(&mut self, _id: &mut NodeId) {
+        // Do nothing.
+    }
+
+    fn visit_span(&mut self, _sp: &mut Span) {
+        // Do nothing.
+    }
+}
+
+/// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
+/// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
+/// method.
+//
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
+    unsafe { std::ptr::write(t, f(std::ptr::read(t))); }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+#[inline]
+pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
+    for elem in elems {
+        visit_elem(elem);
+    }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+#[inline]
+pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
+    if let Some(elem) = opt {
+        visit_elem(elem);
+    }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
+    visit_vec(attrs, |attr| vis.visit_attribute(attr));
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
+    for attr in attrs.iter_mut() {
+        vis.visit_attribute(attr);
+    }
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
+    exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
+    visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+}
+
+// No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
+pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
+    vis.visit_fn_header(header);
+    vis.visit_fn_decl(decl);
+}
+
+pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
+    let UseTree { prefix, kind, span } = use_tree;
+    vis.visit_path(prefix);
+    match kind {
+        UseTreeKind::Simple(rename, id1, id2) => {
+            visit_opt(rename, |rename| vis.visit_ident(rename));
+            vis.visit_id(id1);
+            vis.visit_id(id2);
+        }
+        UseTreeKind::Nested(items) => {
+            for (tree, id) in items {
+                vis.visit_use_tree(tree);
+                vis.visit_id(id);
+            }
+        }
+        UseTreeKind::Glob => {}
+    }
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_arm<T: MutVisitor>(Arm { attrs, pats, guard, body }: &mut Arm, vis: &mut T) {
+    visit_attrs(attrs, vis);
+    visit_vec(pats, |pat| vis.visit_pat(pat));
+    visit_opt(guard, |guard| vis.visit_guard(guard));
+    vis.visit_expr(body);
+}
+
+pub fn noop_visit_guard<T: MutVisitor>(g: &mut Guard, vis: &mut T) {
+    match g {
+        Guard::If(e) => vis.visit_expr(e),
+    }
+}
+
+pub fn noop_visit_ty_binding<T: MutVisitor>(TypeBinding { id, ident, ty, span }: &mut TypeBinding,
+                                            vis: &mut T) {
+    vis.visit_id(id);
+    vis.visit_ident(ident);
+    vis.visit_ty(ty);
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
+    let Ty { id, node, span } = ty.deref_mut();
+    vis.visit_id(id);
+    match node {
+        TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err | TyKind::Never => {}
+        TyKind::Slice(ty) => vis.visit_ty(ty),
+        TyKind::Ptr(mt) => vis.visit_mt(mt),
+        TyKind::Rptr(lt, mt) => {
+            visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
+            vis.visit_mt(mt);
+        }
+        TyKind::BareFn(bft) => {
+            let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
+            vis.visit_generic_params(generic_params);
+            vis.visit_fn_decl(decl);
+        }
+        TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
+        TyKind::Paren(ty) => vis.visit_ty(ty),
+        TyKind::Path(qself, path) => {
+            vis.visit_qself(qself);
+            vis.visit_path(path);
+        }
+        TyKind::Array(ty, length) => {
+            vis.visit_ty(ty);
+            vis.visit_anon_const(length);
+        }
+        TyKind::Typeof(expr) => vis.visit_anon_const(expr),
+        TyKind::TraitObject(bounds, _syntax) =>
+            visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
+        TyKind::ImplTrait(id, bounds) => {
+            vis.visit_id(id);
+            visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+        }
+        TyKind::Mac(mac) => vis.visit_mac(mac),
+    }
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
+    let ForeignMod { abi: _, items} = foreign_mod;
+    items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
+}
+
+pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
+    let Spanned { node: Variant_ { ident, attrs, data, disr_expr }, span } = variant;
+    vis.visit_ident(ident);
+    visit_attrs(attrs, vis);
+    vis.visit_variant_data(data);
+    visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
+    vis.visit_span(span);
+    for PathSegment { ident, id, args } in segments {
+        vis.visit_ident(ident);
+        vis.visit_id(id);
+        visit_opt(args, |args| vis.visit_generic_args(args));
+    }
+}
+
+pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
+    visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
+        vis.visit_ty(ty);
+        vis.visit_span(path_span);
+    })
+}
+
+pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
+    match generic_args {
+        GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
+        GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
+    }
+}
+
+pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
+    match arg {
+        GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
+        GenericArg::Type(ty) => vis.visit_ty(ty),
+        GenericArg::Const(ct) => vis.visit_anon_const(ct),
+    }
+}
+
+pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
+                                                                vis: &mut T) {
+    let AngleBracketedArgs { args, bindings, span } = data;
+    visit_vec(args, |arg| vis.visit_generic_arg(arg));
+    visit_vec(bindings, |binding| vis.visit_ty_binding(binding));
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
+                                                              vis: &mut T) {
+    let ParenthesizedArgs { inputs, output, span } = args;
+    visit_vec(inputs, |input| vis.visit_ty(input));
+    visit_opt(output, |output| vis.visit_ty(output));
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
+    let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
+    vis.visit_id(id);
+    vis.visit_pat(pat);
+    visit_opt(ty, |ty| vis.visit_ty(ty));
+    visit_opt(init, |init| vis.visit_expr(init));
+    vis.visit_span(span);
+    visit_thin_attrs(attrs, vis);
+}
+
+pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
+    let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
+    vis.visit_path(path);
+    vis.visit_tts(tokens);
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
+    let Mac_ { path, delim: _, tts } = node;
+    vis.visit_path(path);
+    vis.visit_tts(tts);
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
+    let MacroDef { tokens, legacy: _ } = macro_def;
+    vis.visit_tts(tokens);
+}
+
+pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
+    let Spanned { node, span } = li;
+    match node {
+        NestedMetaItemKind::MetaItem(mi) => vis.visit_meta_item(mi),
+        NestedMetaItemKind::Literal(_lit) => {}
+    }
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
+    let MetaItem { ident: _, node, span } = mi;
+    match node {
+        MetaItemKind::Word => {}
+        MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
+        MetaItemKind::NameValue(_s) => {}
+    }
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_arg<T: MutVisitor>(Arg { id, pat, ty }: &mut Arg, vis: &mut T) {
+    vis.visit_id(id);
+    vis.visit_pat(pat);
+    vis.visit_ty(ty);
+}
+
+pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
+    match tt {
+        TokenTree::Token(span, tok) => {
+            vis.visit_span(span);
+            vis.visit_token(tok);
+        }
+        TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
+            vis.visit_span(open);
+            vis.visit_span(close);
+            vis.visit_tts(tts);
+        }
+    }
+}
+
+pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
+    visit_opt(tts, |tts| {
+        let tts = Lrc::make_mut(tts);
+        visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
+    })
+}
+
+// apply ident visitor if it's an ident, apply other visits to interpolated nodes
+pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
+    match t {
+        token::Ident(id, _is_raw) => vis.visit_ident(id),
+        token::Lifetime(id) => vis.visit_ident(id),
+        token::Interpolated(nt) => {
+            let nt = Lrc::make_mut(nt);
+            vis.visit_interpolated(&mut nt.0);
+            nt.1 = token::LazyTokenStream::new();
+        }
+        _ => {}
+    }
+}
+
+/// Apply visitor to elements of interpolated nodes.
+//
+// N.B., this can occur only when applying a visitor to partially expanded
+// code, where parsed pieces have gotten implanted ito *other* macro
+// invocations. This is relevant for macro hygiene, but possibly not elsewhere.
+//
+// One problem here occurs because the types for flat_map_item, flat_map_stmt,
+// etc. allow the visitor to return *multiple* items; this is a problem for the
+// nodes here, because they insist on having exactly one piece. One solution
+// would be to mangle the MutVisitor trait to include one-to-many and
+// one-to-one versions of these entry points, but that would probably confuse a
+// lot of people and help very few. Instead, I'm just going to put in dynamic
+// checks. I think the performance impact of this will be pretty much
+// nonexistent. The danger is that someone will apply a MutVisitor to a
+// partially expanded node, and will be confused by the fact that their
+// "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
+// nodes. Hopefully they'll wind up reading this comment, and doing something
+// appropriate.
+//
+// BTW, design choice: I considered just changing the type of, e.g., NtItem to
+// contain multiple items, but decided against it when I looked at
+// parse_item_or_view_item and tried to figure out what I would do with
+// multiple items there....
+pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
+    match nt {
+        token::NtItem(item) =>
+            visit_clobber(item, |item| {
+                // This is probably okay, because the only visitors likely to
+                // peek inside interpolated nodes will be renamings/markings,
+                // which map single items to single items.
+                vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
+            }),
+        token::NtBlock(block) => vis.visit_block(block),
+        token::NtStmt(stmt) =>
+            visit_clobber(stmt, |stmt| {
+                // See reasoning above.
+                vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
+            }),
+        token::NtPat(pat) => vis.visit_pat(pat),
+        token::NtExpr(expr) => vis.visit_expr(expr),
+        token::NtTy(ty) => vis.visit_ty(ty),
+        token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
+        token::NtLifetime(ident) => vis.visit_ident(ident),
+        token::NtLiteral(expr) => vis.visit_expr(expr),
+        token::NtMeta(meta) => vis.visit_meta_item(meta),
+        token::NtPath(path) => vis.visit_path(path),
+        token::NtTT(tt) => vis.visit_tt(tt),
+        token::NtArm(arm) => vis.visit_arm(arm),
+        token::NtImplItem(item) =>
+            visit_clobber(item, |item| {
+                // See reasoning above.
+                vis.flat_map_impl_item(item)
+                    .expect_one("expected visitor to produce exactly one item")
+            }),
+        token::NtTraitItem(item) =>
+            visit_clobber(item, |item| {
+                // See reasoning above.
+                vis.flat_map_trait_item(item)
+                    .expect_one("expected visitor to produce exactly one item")
+            }),
+        token::NtGenerics(generics) => vis.visit_generics(generics),
+        token::NtWhereClause(where_clause) => vis.visit_where_clause(where_clause),
+        token::NtArg(arg) => vis.visit_arg(arg),
+        token::NtVis(visib) => vis.visit_vis(visib),
+        token::NtForeignItem(item) =>
+            visit_clobber(item, |item| {
+                // See reasoning above.
+                vis.flat_map_foreign_item(item)
+                    .expect_one("expected visitor to produce exactly one item")
+            }),
+    }
+}
+
+pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
+    match asyncness {
+        IsAsync::Async { closure_id, return_impl_trait_id } => {
+            vis.visit_id(closure_id);
+            vis.visit_id(return_impl_trait_id);
+        }
+        IsAsync::NotAsync => {}
+    }
+}
+
+pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
+    let FnDecl { inputs, output, variadic: _ } = decl.deref_mut();
+    visit_vec(inputs, |input| vis.visit_arg(input));
+    match output {
+        FunctionRetTy::Default(span) => vis.visit_span(span),
+        FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
+    }
+}
+
+pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
+    match pb {
+        GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
+        GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
+    }
+}
+
+pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
+    let GenericParam { id, ident, attrs, bounds, kind } = param;
+    vis.visit_id(id);
+    vis.visit_ident(ident);
+    visit_thin_attrs(attrs, vis);
+    visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
+    match kind {
+        GenericParamKind::Lifetime => {}
+        GenericParamKind::Type { default } => {
+            visit_opt(default, |default| vis.visit_ty(default));
+        }
+        GenericParamKind::Const { ty } => {
+            vis.visit_ty(ty);
+        }
+    }
+}
+
+pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
+    visit_vec(params, |param| vis.visit_generic_param(param));
+}
+
+pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
+    vis.visit_ident(ident);
+}
+
+fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
+    vis.visit_id(id);
+    vis.visit_ident(ident);
+}
+
+pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
+    let Generics { params, where_clause, span } = generics;
+    vis.visit_generic_params(params);
+    vis.visit_where_clause(where_clause);
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
+    let WhereClause { id, predicates, span } = wc;
+    vis.visit_id(id);
+    visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
+    match pred {
+        WherePredicate::BoundPredicate(bp) => {
+            let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
+            vis.visit_span(span);
+            vis.visit_generic_params(bound_generic_params);
+            vis.visit_ty(bounded_ty);
+            visit_vec(bounds, |bound| vis.visit_param_bound(bound));
+        }
+        WherePredicate::RegionPredicate(rp) => {
+            let WhereRegionPredicate { span, lifetime, bounds } = rp;
+            vis.visit_span(span);
+            noop_visit_lifetime(lifetime, vis);
+            visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
+        }
+        WherePredicate::EqPredicate(ep) => {
+            let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
+            vis.visit_id(id);
+            vis.visit_span(span);
+            vis.visit_ty(lhs_ty);
+            vis.visit_ty(rhs_ty);
+        }
+    }
+}
+
+pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
+    match vdata {
+        VariantData::Struct(fields, id) |
+        VariantData::Tuple(fields, id) => {
+            visit_vec(fields, |field| vis.visit_struct_field(field));
+            vis.visit_id(id);
+        }
+        VariantData::Unit(id) => vis.visit_id(id),
+    }
+}
+
+pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
+    vis.visit_path(path);
+    vis.visit_id(ref_id);
+}
+
+pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
+    let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
+    vis.visit_generic_params(bound_generic_params);
+    vis.visit_trait_ref(trait_ref);
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
+    let StructField { span, ident, vis, id, ty, attrs } = f;
+    visitor.visit_span(span);
+    visit_opt(ident, |ident| visitor.visit_ident(ident));
+    visitor.visit_vis(vis);
+    visitor.visit_id(id);
+    visitor.visit_ty(ty);
+    visit_attrs(attrs, visitor);
+}
+
+pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
+    let Field { ident, expr, span, is_shorthand: _, attrs } = f;
+    vis.visit_ident(ident);
+    vis.visit_expr(expr);
+    vis.visit_span(span);
+    visit_thin_attrs(attrs, vis);
+}
+
+pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
+    vis.visit_ty(ty);
+}
+
+pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
+    let Block { id, stmts, rules: _, span } = block.deref_mut();
+    vis.visit_id(id);
+    stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
+    match kind {
+        ItemKind::ExternCrate(_orig_name) => {}
+        ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
+        ItemKind::Static(ty, _mut, expr) => {
+            vis.visit_ty(ty);
+            vis.visit_expr(expr);
+        }
+        ItemKind::Const(ty, expr) => {
+            vis.visit_ty(ty);
+            vis.visit_expr(expr);
+        }
+        ItemKind::Fn(decl, header, generics, body) => {
+            vis.visit_fn_decl(decl);
+            vis.visit_fn_header(header);
+            vis.visit_generics(generics);
+            vis.visit_block(body);
+        }
+        ItemKind::Mod(m) => vis.visit_mod(m),
+        ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
+        ItemKind::GlobalAsm(_ga) => {}
+        ItemKind::Ty(ty, generics) => {
+            vis.visit_ty(ty);
+            vis.visit_generics(generics);
+        }
+        ItemKind::Existential(bounds, generics) => {
+            visit_bounds(bounds, vis);
+            vis.visit_generics(generics);
+        }
+        ItemKind::Enum(EnumDef { variants }, generics) => {
+            visit_vec(variants, |variant| vis.visit_variant(variant));
+            vis.visit_generics(generics);
+        }
+        ItemKind::Struct(variant_data, generics) |
+        ItemKind::Union(variant_data, generics) => {
+            vis.visit_variant_data(variant_data);
+            vis.visit_generics(generics);
+        }
+        ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
+            vis.visit_generics(generics);
+            visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
+            vis.visit_ty(ty);
+            items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
+        }
+        ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
+            vis.visit_generics(generics);
+            visit_bounds(bounds, vis);
+            items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
+        }
+        ItemKind::TraitAlias(generics, bounds) => {
+            vis.visit_generics(generics);
+            visit_bounds(bounds, vis);
+        }
+        ItemKind::Mac(m) => vis.visit_mac(m),
+        ItemKind::MacroDef(def) => vis.visit_macro_def(def),
+    }
+}
+
+pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
+    -> SmallVec<[TraitItem; 1]>
+{
+    let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
+    vis.visit_id(id);
+    vis.visit_ident(ident);
+    visit_attrs(attrs, vis);
+    vis.visit_generics(generics);
+    match node {
+        TraitItemKind::Const(ty, default) => {
+            vis.visit_ty(ty);
+            visit_opt(default, |default| vis.visit_expr(default));
+        }
+        TraitItemKind::Method(sig, body) => {
+            visit_method_sig(sig, vis);
+            visit_opt(body, |body| vis.visit_block(body));
+        }
+        TraitItemKind::Type(bounds, default) => {
+            visit_bounds(bounds, vis);
+            visit_opt(default, |default| vis.visit_ty(default));
+        }
+        TraitItemKind::Macro(mac) => {
+            vis.visit_mac(mac);
+        }
+    }
+    vis.visit_span(span);
+
+    smallvec![item]
+}
+
+pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
+                                              -> SmallVec<[ImplItem; 1]>
+{
+    let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
+        &mut item;
+    visitor.visit_id(id);
+    visitor.visit_ident(ident);
+    visitor.visit_vis(vis);
+    visit_attrs(attrs, visitor);
+    visitor.visit_generics(generics);
+    match node  {
+        ImplItemKind::Const(ty, expr) => {
+            visitor.visit_ty(ty);
+            visitor.visit_expr(expr);
+        }
+        ImplItemKind::Method(sig, body) => {
+            visit_method_sig(sig, visitor);
+            visitor.visit_block(body);
+        }
+        ImplItemKind::Type(ty) => visitor.visit_ty(ty),
+        ImplItemKind::Existential(bounds) => visit_bounds(bounds, visitor),
+        ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
+    }
+    visitor.visit_span(span);
+
+    smallvec![item]
+}
+
+pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
+    let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
+    vis.visit_asyncness(asyncness);
+}
+
+pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
+    vis.visit_span(inner);
+    items.flat_map_in_place(|item| vis.flat_map_item(item));
+}
+
+pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
+    visit_clobber(krate, |Crate { module, attrs, span }| {
+        let item = P(Item {
+            ident: keywords::Invalid.ident(),
+            attrs,
+            id: DUMMY_NODE_ID,
+            vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
+            span,
+            node: ItemKind::Mod(module),
+            tokens: None,
+        });
+        let items = vis.flat_map_item(item);
+
+        let len = items.len();
+        if len == 0 {
+            let module = Mod { inner: span, items: vec![], inline: true };
+            Crate { module, attrs: vec![], span }
+        } else if len == 1 {
+            let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
+            match node {
+                ItemKind::Mod(module) => Crate { module, attrs, span },
+                _ => panic!("visitor converted a module to not a module"),
+            }
+        } else {
+            panic!("a crate cannot expand to more than one item");
+        }
+    });
+}
+
+// Mutate one item into possibly many items.
+pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
+                                         -> SmallVec<[P<Item>; 1]> {
+    let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
+    visitor.visit_ident(ident);
+    visit_attrs(attrs, visitor);
+    visitor.visit_id(id);
+    visitor.visit_item_kind(node);
+    visitor.visit_vis(vis);
+    visitor.visit_span(span);
+
+    // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
+    //        an ICE during resolve... odd!
+
+    smallvec![item]
+}
+
+pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
+    -> SmallVec<[ForeignItem; 1]>
+{
+    let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
+    visitor.visit_ident(ident);
+    visit_attrs(attrs, visitor);
+    match node {
+        ForeignItemKind::Fn(fdec, generics) => {
+            visitor.visit_fn_decl(fdec);
+            visitor.visit_generics(generics);
+        }
+        ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
+        ForeignItemKind::Ty => {}
+        ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
+    }
+    visitor.visit_id(id);
+    visitor.visit_span(span);
+    visitor.visit_vis(vis);
+
+    smallvec![item]
+}
+
+pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
+    let Pat { id, node, span } = pat.deref_mut();
+    vis.visit_id(id);
+    match node {
+        PatKind::Wild => {}
+        PatKind::Ident(_binding_mode, ident, sub) => {
+            vis.visit_ident(ident);
+            visit_opt(sub, |sub| vis.visit_pat(sub));
+        }
+        PatKind::Lit(e) => vis.visit_expr(e),
+        PatKind::TupleStruct(path, pats, _ddpos) => {
+            vis.visit_path(path);
+            visit_vec(pats, |pat| vis.visit_pat(pat));
+        }
+        PatKind::Path(qself, path) => {
+            vis.visit_qself(qself);
+            vis.visit_path(path);
+        }
+        PatKind::Struct(path, fields, _etc) => {
+            vis.visit_path(path);
+            for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
+                vis.visit_ident(ident);
+                vis.visit_pat(pat);
+                visit_thin_attrs(attrs, vis);
+                vis.visit_span(span);
+            };
+        }
+        PatKind::Tuple(elts, _ddpos) => visit_vec(elts, |elt| vis.visit_pat(elt)),
+        PatKind::Box(inner) => vis.visit_pat(inner),
+        PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
+        PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
+            vis.visit_expr(e1);
+            vis.visit_expr(e2);
+            vis.visit_span(span);
+        }
+        PatKind::Slice(before, slice, after) => {
+            visit_vec(before, |pat| vis.visit_pat(pat));
+            visit_opt(slice, |slice| vis.visit_pat(slice));
+            visit_vec(after, |pat| vis.visit_pat(pat));
+        }
+        PatKind::Paren(inner) => vis.visit_pat(inner),
+        PatKind::Mac(mac) => vis.visit_mac(mac),
+    }
+    vis.visit_span(span);
+}
+
+pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
+    vis.visit_id(id);
+    vis.visit_expr(value);
+}
+
+pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
+    match node {
+        ExprKind::Box(expr) => vis.visit_expr(expr),
+        ExprKind::ObsoleteInPlace(a, b) => {
+            vis.visit_expr(a);
+            vis.visit_expr(b);
+        }
+        ExprKind::Array(exprs) => visit_exprs(exprs, vis),
+        ExprKind::Repeat(expr, count) => {
+            vis.visit_expr(expr);
+            vis.visit_anon_const(count);
+        }
+        ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
+        ExprKind::Call(f, args) => {
+            vis.visit_expr(f);
+            visit_exprs(args, vis);
+        }
+        ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
+            vis.visit_ident(ident);
+            vis.visit_id(id);
+            visit_opt(args, |args| vis.visit_generic_args(args));
+            visit_exprs(exprs, vis);
+        }
+        ExprKind::Binary(_binop, lhs, rhs) => {
+            vis.visit_expr(lhs);
+            vis.visit_expr(rhs);
+        }
+        ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
+        ExprKind::Lit(_lit) => {}
+        ExprKind::Cast(expr, ty) => {
+            vis.visit_expr(expr);
+            vis.visit_ty(ty);
+        }
+        ExprKind::Type(expr, ty) => {
+            vis.visit_expr(expr);
+            vis.visit_ty(ty);
+        }
+        ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
+        ExprKind::If(cond, tr, fl) => {
+            vis.visit_expr(cond);
+            vis.visit_block(tr);
+            visit_opt(fl, |fl| vis.visit_expr(fl));
+        }
+        ExprKind::IfLet(pats, expr, tr, fl) => {
+            visit_vec(pats, |pat| vis.visit_pat(pat));
+            vis.visit_expr(expr);
+            vis.visit_block(tr);
+            visit_opt(fl, |fl| vis.visit_expr(fl));
+        }
+        ExprKind::While(cond, body, label) => {
+            vis.visit_expr(cond);
+            vis.visit_block(body);
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::WhileLet(pats, expr, body, label) => {
+            visit_vec(pats, |pat| vis.visit_pat(pat));
+            vis.visit_expr(expr);
+            vis.visit_block(body);
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::ForLoop(pat, iter, body, label) => {
+            vis.visit_pat(pat);
+            vis.visit_expr(iter);
+            vis.visit_block(body);
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::Loop(body, label) => {
+            vis.visit_block(body);
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::Match(expr, arms) => {
+            vis.visit_expr(expr);
+            visit_vec(arms, |arm| vis.visit_arm(arm));
+        }
+        ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
+            vis.visit_asyncness(asyncness);
+            vis.visit_fn_decl(decl);
+            vis.visit_expr(body);
+            vis.visit_span(span);
+        }
+        ExprKind::Block(blk, label) => {
+            vis.visit_block(blk);
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::Async(_capture_by, node_id, body) => {
+            vis.visit_id(node_id);
+            vis.visit_block(body);
+        }
+        ExprKind::Assign(el, er) => {
+            vis.visit_expr(el);
+            vis.visit_expr(er);
+        }
+        ExprKind::AssignOp(_op, el, er) => {
+            vis.visit_expr(el);
+            vis.visit_expr(er);
+        }
+        ExprKind::Field(el, ident) => {
+            vis.visit_expr(el);
+            vis.visit_ident(ident);
+        }
+        ExprKind::Index(el, er) => {
+            vis.visit_expr(el);
+            vis.visit_expr(er);
+        }
+        ExprKind::Range(e1, e2, _lim) => {
+            visit_opt(e1, |e1| vis.visit_expr(e1));
+            visit_opt(e2, |e2| vis.visit_expr(e2));
+        }
+        ExprKind::Path(qself, path) => {
+            vis.visit_qself(qself);
+            vis.visit_path(path);
+        }
+        ExprKind::Break(label, expr) => {
+            visit_opt(label, |label| vis.visit_label(label));
+            visit_opt(expr, |expr| vis.visit_expr(expr));
+        }
+        ExprKind::Continue(label) => {
+            visit_opt(label, |label| vis.visit_label(label));
+        }
+        ExprKind::Ret(expr) => {
+            visit_opt(expr, |expr| vis.visit_expr(expr));
+        }
+        ExprKind::InlineAsm(asm) => {
+            let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
+                            alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
+            for out in outputs {
+                let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
+                vis.visit_expr(expr);
+            }
+            visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
+        }
+        ExprKind::Mac(mac) => vis.visit_mac(mac),
+        ExprKind::Struct(path, fields, expr) => {
+            vis.visit_path(path);
+            visit_vec(fields, |field| vis.visit_field(field));
+            visit_opt(expr, |expr| vis.visit_expr(expr));
+        },
+        ExprKind::Paren(expr) => {
+            vis.visit_expr(expr);
+
+            // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
+            *id = expr.id;
+            vis.visit_span(span);
+            visit_thin_attrs(attrs, vis);
+            return;
+        }
+        ExprKind::Yield(expr) => {
+            visit_opt(expr, |expr| vis.visit_expr(expr));
+        }
+        ExprKind::Try(expr) => vis.visit_expr(expr),
+        ExprKind::TryBlock(body) => vis.visit_block(body),
+        ExprKind::Err => {}
+    }
+    vis.visit_id(id);
+    vis.visit_span(span);
+    visit_thin_attrs(attrs, vis);
+}
+
+pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
+    Some({ vis.visit_expr(&mut e); e })
+}
+
+pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
+    -> SmallVec<[Stmt; 1]>
+{
+    vis.visit_id(&mut id);
+    vis.visit_span(&mut span);
+    noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
+        Stmt { id, node, span }
+    }).collect()
+}
+
+pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
+                                              -> SmallVec<[StmtKind; 1]> {
+    match node {
+        StmtKind::Local(mut local) =>
+            smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
+        StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
+        StmtKind::Expr(expr) => {
+            vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
+        }
+        StmtKind::Semi(expr) => {
+            vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
+        }
+        StmtKind::Mac(mut mac) => {
+            let (mac_, _semi, attrs) = mac.deref_mut();
+            vis.visit_mac(mac_);
+            visit_thin_attrs(attrs, vis);
+            smallvec![StmtKind::Mac(mac)]
+        }
+    }
+}
+
+pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
+    match node {
+        VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
+        VisibilityKind::Restricted { path, id } => {
+            vis.visit_path(path);
+            vis.visit_id(id);
+        }
+    }
+    vis.visit_span(span);
+}
+
+#[cfg(test)]
+mod tests {
+    use std::io;
+    use crate::ast::{self, Ident};
+    use crate::util::parser_testing::{string_to_crate, matches_codepattern};
+    use crate::print::pprust;
+    use crate::mut_visit;
+    use crate::with_globals;
+    use super::*;
+
+    // this version doesn't care about getting comments or docstrings in.
+    fn fake_print_crate(s: &mut pprust::State<'_>,
+                        krate: &ast::Crate) -> io::Result<()> {
+        s.print_mod(&krate.module, &krate.attrs)
+    }
+
+    // change every identifier to "zz"
+    struct ToZzIdentMutVisitor;
+
+    impl MutVisitor for ToZzIdentMutVisitor {
+        fn visit_ident(&mut self, ident: &mut ast::Ident) {
+            *ident = Ident::from_str("zz");
+        }
+        fn visit_mac(&mut self, mac: &mut ast::Mac) {
+            mut_visit::noop_visit_mac(mac, self)
+        }
+    }
+
+    // maybe add to expand.rs...
+    macro_rules! assert_pred {
+        ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
+            {
+                let pred_val = $pred;
+                let a_val = $a;
+                let b_val = $b;
+                if !(pred_val(&a_val, &b_val)) {
+                    panic!("expected args satisfying {}, got {} and {}",
+                          $predname, a_val, b_val);
+                }
+            }
+        )
+    }
+
+    // make sure idents get transformed everywhere
+    #[test] fn ident_transformation () {
+        with_globals(|| {
+            let mut zz_visitor = ToZzIdentMutVisitor;
+            let mut krate = string_to_crate(
+                "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
+            zz_visitor.visit_crate(&mut krate);
+            assert_pred!(
+                matches_codepattern,
+                "matches_codepattern",
+                pprust::to_string(|s| fake_print_crate(s, &krate)),
+                "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
+        })
+    }
+
+    // even inside macro defs....
+    #[test] fn ident_transformation_in_defs () {
+        with_globals(|| {
+            let mut zz_visitor = ToZzIdentMutVisitor;
+            let mut krate = string_to_crate(
+                "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
+                (g $(d $d $e)+))} ".to_string());
+            zz_visitor.visit_crate(&mut krate);
+            assert_pred!(
+                matches_codepattern,
+                "matches_codepattern",
+                pprust::to_string(|s| fake_print_crate(s, &krate)),
+                "macro_rules! zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());
+        })
+    }
+}
+
diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index 914a0667ebf0c..b36ca0574cb8d 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -1,10 +1,12 @@
-use attr;
-use ast;
-use source_map::respan;
-use parse::{SeqSep, PResult};
-use parse::token::{self, Nonterminal, DelimToken};
-use parse::parser::{Parser, TokenType, PathStyle};
-use tokenstream::{TokenStream, TokenTree};
+use crate::attr;
+use crate::ast;
+use crate::source_map::respan;
+use crate::parse::{SeqSep, PResult};
+use crate::parse::token::{self, Nonterminal, DelimToken};
+use crate::parse::parser::{Parser, TokenType, PathStyle};
+use crate::tokenstream::{TokenStream, TokenTree};
+
+use log::debug;
 
 #[derive(Debug)]
 enum InnerAttributeParsePolicy<'a> {
@@ -74,7 +76,7 @@ impl<'a> Parser<'a> {
     /// The same as `parse_attribute`, except it takes in an `InnerAttributeParsePolicy`
     /// that prescribes how to handle inner attributes.
     fn parse_attribute_with_inner_parse_policy(&mut self,
-                                               inner_parse_policy: InnerAttributeParsePolicy)
+                                               inner_parse_policy: InnerAttributeParsePolicy<'_>)
                                                -> PResult<'a, ast::Attribute> {
         debug!("parse_attribute_with_inner_parse_policy: inner_parse_policy={:?} self.token={:?}",
                inner_parse_policy,
diff --git a/src/libsyntax/parse/classify.rs b/src/libsyntax/parse/classify.rs
index a1cdfd9146a1e..b4103440e3577 100644
--- a/src/libsyntax/parse/classify.rs
+++ b/src/libsyntax/parse/classify.rs
@@ -2,7 +2,7 @@
 
 // Predicates on exprs and stmts that the pretty-printer and parser use
 
-use ast;
+use crate::ast;
 
 /// Does this expression require a semicolon to be treated
 /// as a statement? The negation of this: 'can this expression
diff --git a/src/libsyntax/parse/lexer/comments.rs b/src/libsyntax/parse/lexer/comments.rs
index ffc480d829d89..74fff3324eacf 100644
--- a/src/libsyntax/parse/lexer/comments.rs
+++ b/src/libsyntax/parse/lexer/comments.rs
@@ -1,11 +1,13 @@
-pub use self::CommentStyle::*;
+pub use CommentStyle::*;
+
+use crate::ast;
+use crate::source_map::SourceMap;
+use crate::parse::lexer::{is_block_doc_comment, is_pattern_whitespace};
+use crate::parse::lexer::{self, ParseSess, StringReader, TokenAndSpan};
+use crate::print::pprust;
 
-use ast;
-use source_map::SourceMap;
 use syntax_pos::{BytePos, CharPos, Pos, FileName};
-use parse::lexer::{is_block_doc_comment, is_pattern_whitespace};
-use parse::lexer::{self, ParseSess, StringReader, TokenAndSpan};
-use print::pprust;
+use log::debug;
 
 use std::io::Read;
 use std::usize;
@@ -135,7 +137,7 @@ pub fn strip_doc_comment_decoration(comment: &str) -> String {
     panic!("not a doc-comment: {}", comment);
 }
 
-fn push_blank_line_comment(rdr: &StringReader, comments: &mut Vec<Comment>) {
+fn push_blank_line_comment(rdr: &StringReader<'_>, comments: &mut Vec<Comment>) {
     debug!(">>> blank-line comment");
     comments.push(Comment {
         style: BlankLine,
@@ -144,7 +146,10 @@ fn push_blank_line_comment(rdr: &StringReader, comments: &mut Vec<Comment>) {
     });
 }
 
-fn consume_whitespace_counting_blank_lines(rdr: &mut StringReader, comments: &mut Vec<Comment>) {
+fn consume_whitespace_counting_blank_lines(
+    rdr: &mut StringReader<'_>,
+    comments: &mut Vec<Comment>
+) {
     while is_pattern_whitespace(rdr.ch) && !rdr.is_eof() {
         if rdr.ch_is('\n') {
             push_blank_line_comment(rdr, &mut *comments);
@@ -153,7 +158,7 @@ fn consume_whitespace_counting_blank_lines(rdr: &mut StringReader, comments: &mu
     }
 }
 
-fn read_shebang_comment(rdr: &mut StringReader,
+fn read_shebang_comment(rdr: &mut StringReader<'_>,
                         code_to_the_left: bool,
                         comments: &mut Vec<Comment>) {
     debug!(">>> shebang comment");
@@ -166,7 +171,7 @@ fn read_shebang_comment(rdr: &mut StringReader,
     });
 }
 
-fn read_line_comments(rdr: &mut StringReader,
+fn read_line_comments(rdr: &mut StringReader<'_>,
                       code_to_the_left: bool,
                       comments: &mut Vec<Comment>) {
     debug!(">>> line comments");
@@ -192,9 +197,9 @@ fn read_line_comments(rdr: &mut StringReader,
     }
 }
 
-/// Returns None if the first col chars of s contain a non-whitespace char.
-/// Otherwise returns Some(k) where k is first char offset after that leading
-/// whitespace.  Note k may be outside bounds of s.
+/// Returns `None` if the first `col` chars of `s` contain a non-whitespace char.
+/// Otherwise returns `Some(k)` where `k` is first char offset after that leading
+/// whitespace. Note that `k` may be outside bounds of `s`.
 fn all_whitespace(s: &str, col: CharPos) -> Option<usize> {
     let mut idx = 0;
     for (i, ch) in s.char_indices().take(col.to_usize()) {
@@ -222,7 +227,7 @@ fn trim_whitespace_prefix_and_push_line(lines: &mut Vec<String>, s: String, col:
     lines.push(s1);
 }
 
-fn read_block_comment(rdr: &mut StringReader,
+fn read_block_comment(rdr: &mut StringReader<'_>,
                       code_to_the_left: bool,
                       comments: &mut Vec<Comment>) {
     debug!(">>> block comment");
@@ -312,7 +317,7 @@ fn read_block_comment(rdr: &mut StringReader,
 }
 
 
-fn consume_comment(rdr: &mut StringReader,
+fn consume_comment(rdr: &mut StringReader<'_>,
                    comments: &mut Vec<Comment>,
                    code_to_the_left: &mut bool,
                    anything_to_the_left: &mut bool) {
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index 0e1c3b4b61f3a..babe0eef20f8c 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -1,9 +1,10 @@
-use ast::{self, Ident};
-use syntax_pos::{self, BytePos, CharPos, Pos, Span, NO_EXPANSION};
-use source_map::{SourceMap, FilePathMapping};
+use crate::ast::{self, Ident};
+use crate::source_map::{SourceMap, FilePathMapping};
+use crate::parse::{token, ParseSess};
+use crate::symbol::{Symbol, keywords};
+
 use errors::{Applicability, FatalError, Diagnostic, DiagnosticBuilder};
-use parse::{token, ParseSess};
-use symbol::{Symbol, keywords};
+use syntax_pos::{BytePos, CharPos, Pos, Span, NO_EXPANSION};
 use core::unicode::property::Pattern_White_Space;
 
 use std::borrow::Cow;
@@ -11,6 +12,7 @@ use std::char;
 use std::iter;
 use std::mem::replace;
 use rustc_data_structures::sync::Lrc;
+use log::debug;
 
 pub mod comments;
 mod tokentrees;
@@ -31,6 +33,15 @@ impl Default for TokenAndSpan {
     }
 }
 
+#[derive(Clone, Debug)]
+pub struct UnmatchedBrace {
+    pub expected_delim: token::DelimToken,
+    pub found_delim: token::DelimToken,
+    pub found_span: Span,
+    pub unclosed_span: Option<Span>,
+    pub candidate_span: Option<Span>,
+}
+
 pub struct StringReader<'a> {
     pub sess: &'a ParseSess,
     /// The absolute offset within the source_map of the next character to read
@@ -56,6 +67,7 @@ pub struct StringReader<'a> {
     span_src_raw: Span,
     /// Stack of open delimiters and their spans. Used for error message.
     open_braces: Vec<(token::DelimToken, Span)>,
+    crate unmatched_braces: Vec<UnmatchedBrace>,
     /// The type and spans for all braces
     ///
     /// Used only for error recovery when arriving to EOF with mismatched braces.
@@ -100,7 +112,7 @@ impl<'a> StringReader<'a> {
         self.unwrap_or_abort(res)
     }
 
-    /// Return the next token. EFFECT: advances the string_reader.
+    /// Returns the next token. EFFECT: advances the string_reader.
     pub fn try_next_token(&mut self) -> Result<TokenAndSpan, ()> {
         assert!(self.fatal_errs.is_empty());
         let ret_val = TokenAndSpan {
@@ -220,6 +232,7 @@ impl<'a> StringReader<'a> {
             span: syntax_pos::DUMMY_SP,
             span_src_raw: syntax_pos::DUMMY_SP,
             open_braces: Vec::new(),
+            unmatched_braces: Vec::new(),
             matching_delim_spans: Vec::new(),
             override_span,
             last_unclosed_found_span: None,
@@ -238,19 +251,6 @@ impl<'a> StringReader<'a> {
         sr
     }
 
-    pub fn new_without_err(sess: &'a ParseSess,
-                           source_file: Lrc<syntax_pos::SourceFile>,
-                           override_span: Option<Span>,
-                           prepend_error_text: &str) -> Result<Self, ()> {
-        let mut sr = StringReader::new_raw(sess, source_file, override_span);
-        if sr.advance_token().is_err() {
-            eprintln!("{}", prepend_error_text);
-            sr.emit_fatal_errors();
-            return Err(());
-        }
-        Ok(sr)
-    }
-
     pub fn new_or_buffered_errs(sess: &'a ParseSess,
                                 source_file: Lrc<syntax_pos::SourceFile>,
                                 override_span: Option<Span>) -> Result<Self, Vec<Diagnostic>> {
@@ -425,7 +425,7 @@ impl<'a> StringReader<'a> {
         self.with_str_from_to(start, self.pos, f)
     }
 
-    /// Create a Name from a given offset to the current offset, each
+    /// Creates a Name from a given offset to the current offset, each
     /// adjusted 1 towards each other (assumes that on either side there is a
     /// single-byte delimiter).
     fn name_from(&self, start: BytePos) -> ast::Name {
@@ -462,7 +462,7 @@ impl<'a> StringReader<'a> {
         }
         return s.into();
 
-        fn translate_crlf_(rdr: &StringReader,
+        fn translate_crlf_(rdr: &StringReader<'_>,
                            start: BytePos,
                            s: &str,
                            mut j: usize,
@@ -670,7 +670,7 @@ impl<'a> StringReader<'a> {
     }
 
     /// If there is whitespace, shebang, or a comment, scan it. Otherwise,
-    /// return None.
+    /// return `None`.
     fn scan_whitespace_or_comment(&mut self) -> Option<TokenAndSpan> {
         match self.ch.unwrap_or('\0') {
             // # to handle shebang at start of file -- this is the entry point
@@ -920,7 +920,7 @@ impl<'a> StringReader<'a> {
     /// in a byte, (non-raw) byte string, char, or (non-raw) string literal.
     /// `start` is the position of `first_source_char`, which is already consumed.
     ///
-    /// Returns true if there was a valid char/byte, false otherwise.
+    /// Returns `true` if there was a valid char/byte.
     fn scan_char_or_byte(&mut self,
                          start: BytePos,
                          first_source_char: char,
@@ -962,7 +962,7 @@ impl<'a> StringReader<'a> {
                                     }
                                     if i != 0 {
                                         suggestion.push('}');
-                                        err.span_suggestion_with_applicability(
+                                        err.span_suggestion(
                                             self.mk_sp(start, self.pos),
                                             "format of unicode escape sequences uses braces",
                                             suggestion,
@@ -1152,7 +1152,7 @@ impl<'a> StringReader<'a> {
         }
     }
 
-    /// Check that a base is valid for a floating literal, emitting a nice
+    /// Checks that a base is valid for a floating literal, emitting a nice
     /// error if it isn't.
     fn check_float_base(&mut self, start_bpos: BytePos, last_bpos: BytePos, base: usize) {
         match base {
@@ -1185,7 +1185,7 @@ impl<'a> StringReader<'a> {
         }
     }
 
-    /// Return the next token from the string, advances the input past that
+    /// Returns the next token from the string, advances the input past that
     /// token, and updates the interner
     fn next_token_inner(&mut self) -> Result<token::Token, ()> {
         let c = self.ch;
@@ -1408,9 +1408,10 @@ impl<'a> StringReader<'a> {
                     // lifetimes shouldn't end with a single quote
                     // if we find one, then this is an invalid character literal
                     if self.ch_is('\'') {
-                        self.fatal_span_verbose(start_with_quote, self.next_pos,
-                                String::from("character literal may only contain one codepoint"))
-                            .raise();
+                        self.err_span_(start_with_quote, self.next_pos,
+                                "character literal may only contain one codepoint");
+                        self.bump();
+                        return Ok(token::Literal(token::Err(Symbol::intern("??")), None))
 
                     }
 
@@ -1439,13 +1440,13 @@ impl<'a> StringReader<'a> {
                             self.sess.span_diagnostic
                                 .struct_span_err(span,
                                                  "character literal may only contain one codepoint")
-                                .span_suggestion_with_applicability(
+                                .span_suggestion(
                                     span,
                                     "if you meant to write a `str` literal, use double quotes",
                                     format!("\"{}\"", &self.src[start..end]),
                                     Applicability::MachineApplicable
                                 ).emit();
-                            return Ok(token::Literal(token::Str_(Symbol::intern("??")), None))
+                            return Ok(token::Literal(token::Err(Symbol::intern("??")), None))
                         }
                         if self.ch_is('\n') || self.is_eof() || self.ch_is('/') {
                             // Only attempt to infer single line string literals. If we encounter
@@ -1878,19 +1879,19 @@ fn char_at(s: &str, byte: usize) -> char {
 mod tests {
     use super::*;
 
-    use ast::{Ident, CrateConfig};
-    use symbol::Symbol;
-    use syntax_pos::{BytePos, Span, NO_EXPANSION};
-    use source_map::SourceMap;
-    use errors;
-    use feature_gate::UnstableFeatures;
-    use parse::token;
+    use crate::ast::{Ident, CrateConfig};
+    use crate::symbol::Symbol;
+    use crate::source_map::SourceMap;
+    use crate::feature_gate::UnstableFeatures;
+    use crate::parse::token;
+    use crate::diagnostics::plugin::ErrorMap;
+    use crate::with_globals;
     use std::io;
     use std::path::PathBuf;
-    use diagnostics::plugin::ErrorMap;
+    use syntax_pos::{BytePos, Span, NO_EXPANSION};
     use rustc_data_structures::fx::FxHashSet;
     use rustc_data_structures::sync::Lock;
-    use with_globals;
+
     fn mk_sess(sm: Lrc<SourceMap>) -> ParseSess {
         let emitter = errors::emitter::EmitterWriter::new(Box::new(io::sink()),
                                                           Some(sm.clone()),
@@ -1955,7 +1956,7 @@ mod tests {
 
     // check that the given reader produces the desired stream
     // of tokens (stop checking after exhausting the expected vec)
-    fn check_tokenization(mut string_reader: StringReader, expected: Vec<token::Token>) {
+    fn check_tokenization(mut string_reader: StringReader<'_>, expected: Vec<token::Token>) {
         for expected_tok in &expected {
             assert_eq!(&string_reader.next_token().tok, expected_tok);
         }
diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs
index d219f29f06c20..0db36c84cdfeb 100644
--- a/src/libsyntax/parse/lexer/tokentrees.rs
+++ b/src/libsyntax/parse/lexer/tokentrees.rs
@@ -1,7 +1,7 @@
-use print::pprust::token_to_string;
-use parse::lexer::StringReader;
-use parse::{token, PResult};
-use tokenstream::{DelimSpan, IsJoint::*, TokenStream, TokenTree, TreeAndJoint};
+use crate::print::pprust::token_to_string;
+use crate::parse::lexer::{StringReader, UnmatchedBrace};
+use crate::parse::{token, PResult};
+use crate::tokenstream::{DelimSpan, IsJoint::*, TokenStream, TokenTree, TreeAndJoint};
 
 impl<'a> StringReader<'a> {
     // Parse a stream of tokens into a list of `TokenTree`s, up to an `Eof`.
@@ -101,38 +101,38 @@ impl<'a> StringReader<'a> {
                     }
                     // Incorrect delimiter.
                     token::CloseDelim(other) => {
-                        let token_str = token_to_string(&self.token);
+                        let mut unclosed_delimiter = None;
+                        let mut candidate = None;
                         if self.last_unclosed_found_span != Some(self.span) {
                             // do not complain about the same unclosed delimiter multiple times
                             self.last_unclosed_found_span = Some(self.span);
-                            let msg = format!("incorrect close delimiter: `{}`", token_str);
-                            let mut err = self.sess.span_diagnostic.struct_span_err(
-                                self.span,
-                                &msg,
-                            );
-                            err.span_label(self.span, "incorrect close delimiter");
                             // This is a conservative error: only report the last unclosed
                             // delimiter. The previous unclosed delimiters could actually be
                             // closed! The parser just hasn't gotten to them yet.
                             if let Some(&(_, sp)) = self.open_braces.last() {
-                                err.span_label(sp, "un-closed delimiter");
+                                unclosed_delimiter = Some(sp);
                             };
                             if let Some(current_padding) = sm.span_to_margin(self.span) {
                                 for (brace, brace_span) in &self.open_braces {
                                     if let Some(padding) = sm.span_to_margin(*brace_span) {
                                         // high likelihood of these two corresponding
                                         if current_padding == padding && brace == &other {
-                                            err.span_label(
-                                                *brace_span,
-                                                "close delimiter possibly meant for this",
-                                            );
+                                            candidate = Some(*brace_span);
                                         }
                                     }
                                 }
                             }
-                            err.emit();
+                            let (tok, _) = self.open_braces.pop().unwrap();
+                            self.unmatched_braces.push(UnmatchedBrace {
+                                expected_delim: tok,
+                                found_delim: other,
+                                found_span: self.span,
+                                unclosed_span: unclosed_delimiter,
+                                candidate_span: candidate,
+                            });
+                        } else {
+                            self.open_braces.pop();
                         }
-                        self.open_braces.pop().unwrap();
 
                         // If the incorrect delimiter matches an earlier opening
                         // delimiter, then don't consume it (it can be used to
diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/libsyntax/parse/lexer/unicode_chars.rs
index c31756714a6c3..7da4284c0e4aa 100644
--- a/src/libsyntax/parse/lexer/unicode_chars.rs
+++ b/src/libsyntax/parse/lexer/unicode_chars.rs
@@ -336,7 +336,7 @@ crate fn check_for_substitution<'a>(reader: &StringReader<'a>,
                 let msg =
                     format!("Unicode character '{}' ({}) looks like '{}' ({}), but it is not",
                             ch, u_name, ascii_char, ascii_name);
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     span,
                     &msg,
                     ascii_char.to_string(),
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index ea205530ca5cc..b2d4d97d57d89 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -1,17 +1,19 @@
-//! The main parser interface
+//! The main parser interface.
+
+use crate::ast::{self, CrateConfig, NodeId};
+use crate::early_buffered_lints::{BufferedEarlyLint, BufferedEarlyLintId};
+use crate::source_map::{SourceMap, FilePathMapping};
+use crate::feature_gate::UnstableFeatures;
+use crate::parse::parser::Parser;
+use crate::symbol::Symbol;
+use crate::tokenstream::{TokenStream, TokenTree};
+use crate::diagnostics::plugin::ErrorMap;
+use crate::print::pprust::token_to_string;
 
+use errors::{FatalError, Level, Handler, ColorConfig, Diagnostic, DiagnosticBuilder};
 use rustc_data_structures::sync::{Lrc, Lock};
-use ast::{self, CrateConfig, NodeId};
-use early_buffered_lints::{BufferedEarlyLint, BufferedEarlyLintId};
-use source_map::{SourceMap, FilePathMapping};
 use syntax_pos::{Span, SourceFile, FileName, MultiSpan};
-use errors::{FatalError, Level, Handler, ColorConfig, Diagnostic, DiagnosticBuilder};
-use feature_gate::UnstableFeatures;
-use parse::parser::Parser;
-use ptr::P;
-use symbol::Symbol;
-use tokenstream::{TokenStream, TokenTree};
-use diagnostics::plugin::ErrorMap;
+use log::debug;
 
 use rustc_data_structures::fx::FxHashSet;
 use std::borrow::Cow;
@@ -36,12 +38,11 @@ pub struct ParseSess {
     pub unstable_features: UnstableFeatures,
     pub config: CrateConfig,
     pub missing_fragment_specifiers: Lock<FxHashSet<Span>>,
-    /// Places where raw identifiers were used. This is used for feature gating
-    /// raw identifiers
+    /// Places where raw identifiers were used. This is used for feature-gating raw identifiers.
     pub raw_identifier_spans: Lock<Vec<Span>>,
-    /// The registered diagnostics codes
+    /// The registered diagnostics codes.
     crate registered_diagnostics: Lock<ErrorMap>,
-    /// Used to determine and report recursive mod inclusions
+    /// Used to determine and report recursive module inclusions.
     included_mod_stack: Lock<Vec<PathBuf>>,
     source_map: Lrc<SourceMap>,
     pub buffered_lints: Lock<Vec<BufferedEarlyLint>>,
@@ -126,50 +127,33 @@ pub fn parse_crate_attrs_from_file<'a>(input: &Path, sess: &'a ParseSess)
 }
 
 pub fn parse_crate_from_source_str(name: FileName, source: String, sess: &ParseSess)
-                                       -> PResult<ast::Crate> {
+                                       -> PResult<'_, ast::Crate> {
     new_parser_from_source_str(sess, name, source).parse_crate_mod()
 }
 
 pub fn parse_crate_attrs_from_source_str(name: FileName, source: String, sess: &ParseSess)
-                                             -> PResult<Vec<ast::Attribute>> {
+                                             -> PResult<'_, Vec<ast::Attribute>> {
     new_parser_from_source_str(sess, name, source).parse_inner_attributes()
 }
 
-crate fn parse_expr_from_source_str(name: FileName, source: String, sess: &ParseSess)
-                                      -> PResult<P<ast::Expr>> {
-    new_parser_from_source_str(sess, name, source).parse_expr()
-}
-
-/// Parses an item.
-///
-/// Returns `Ok(Some(item))` when successful, `Ok(None)` when no item was found, and `Err`
-/// when a syntax error occurred.
-crate fn parse_item_from_source_str(name: FileName, source: String, sess: &ParseSess)
-                                      -> PResult<Option<P<ast::Item>>> {
-    new_parser_from_source_str(sess, name, source).parse_item()
-}
-
-crate fn parse_stmt_from_source_str(name: FileName, source: String, sess: &ParseSess)
-                                      -> PResult<Option<ast::Stmt>> {
-    new_parser_from_source_str(sess, name, source).parse_stmt()
-}
-
-pub fn parse_stream_from_source_str(name: FileName, source: String, sess: &ParseSess,
-                                    override_span: Option<Span>)
-                                    -> TokenStream {
+pub fn parse_stream_from_source_str(
+    name: FileName,
+    source: String,
+    sess: &ParseSess,
+    override_span: Option<Span>,
+) -> (TokenStream, Vec<lexer::UnmatchedBrace>) {
     source_file_to_stream(sess, sess.source_map().new_source_file(name, source), override_span)
 }
 
-/// Create a new parser from a source string
-pub fn new_parser_from_source_str(sess: &ParseSess, name: FileName, source: String)
-                                      -> Parser {
+/// Creates a new parser from a source string.
+pub fn new_parser_from_source_str(sess: &ParseSess, name: FileName, source: String) -> Parser<'_> {
     panictry_buffer!(&sess.span_diagnostic, maybe_new_parser_from_source_str(sess, name, source))
 }
 
-/// Create a new parser from a source string. Returns any buffered errors from lexing the initial
+/// Creates a new parser from a source string. Returns any buffered errors from lexing the initial
 /// token stream.
 pub fn maybe_new_parser_from_source_str(sess: &ParseSess, name: FileName, source: String)
-    -> Result<Parser, Vec<Diagnostic>>
+    -> Result<Parser<'_>, Vec<Diagnostic>>
 {
     let mut parser = maybe_source_file_to_parser(sess,
                                                  sess.source_map().new_source_file(name, source))?;
@@ -177,13 +161,13 @@ pub fn maybe_new_parser_from_source_str(sess: &ParseSess, name: FileName, source
     Ok(parser)
 }
 
-/// Create a new parser, handling errors as appropriate
+/// Creates a new parser, handling errors as appropriate
 /// if the file doesn't exist
 pub fn new_parser_from_file<'a>(sess: &'a ParseSess, path: &Path) -> Parser<'a> {
     source_file_to_parser(sess, file_to_source_file(sess, path, None))
 }
 
-/// Create a new parser, returning buffered diagnostics if the file doesn't
+/// Creates a new parser, returning buffered diagnostics if the file doesn't
 /// exist or from lexing the initial token stream.
 pub fn maybe_new_parser_from_file<'a>(sess: &'a ParseSess, path: &Path)
     -> Result<Parser<'a>, Vec<Diagnostic>> {
@@ -206,19 +190,21 @@ crate fn new_sub_parser_from_file<'a>(sess: &'a ParseSess,
 }
 
 /// Given a source_file and config, return a parser
-fn source_file_to_parser(sess: & ParseSess, source_file: Lrc<SourceFile>) -> Parser {
+fn source_file_to_parser(sess: &ParseSess, source_file: Lrc<SourceFile>) -> Parser<'_> {
     panictry_buffer!(&sess.span_diagnostic,
                      maybe_source_file_to_parser(sess, source_file))
 }
 
 /// Given a source_file and config, return a parser. Returns any buffered errors from lexing the
 /// initial token stream.
-fn maybe_source_file_to_parser(sess: &ParseSess, source_file: Lrc<SourceFile>)
-    -> Result<Parser, Vec<Diagnostic>>
-{
+fn maybe_source_file_to_parser(
+    sess: &ParseSess,
+    source_file: Lrc<SourceFile>,
+) -> Result<Parser<'_>, Vec<Diagnostic>> {
     let end_pos = source_file.end_pos;
-    let mut parser = stream_to_parser(sess, maybe_file_to_stream(sess, source_file, None)?);
-
+    let (stream, unclosed_delims) = maybe_file_to_stream(sess, source_file, None)?;
+    let mut parser = stream_to_parser(sess, stream);
+    parser.unclosed_delims = unclosed_delims;
     if parser.token == token::Eof && parser.span.is_dummy() {
         parser.span = Span::new(end_pos, end_pos, parser.span.ctxt());
     }
@@ -228,7 +214,7 @@ fn maybe_source_file_to_parser(sess: &ParseSess, source_file: Lrc<SourceFile>)
 
 // must preserve old name for now, because quote! from the *existing*
 // compiler expands into it
-pub fn new_parser_from_tts(sess: &ParseSess, tts: Vec<TokenTree>) -> Parser {
+pub fn new_parser_from_tts(sess: &ParseSess, tts: Vec<TokenTree>) -> Parser<'_> {
     stream_to_parser(sess, tts.into_iter().collect())
 }
 
@@ -252,7 +238,7 @@ fn try_file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
 }
 
 /// Given a session and a path and an optional span (for error reporting),
-/// add the path to the session's source_map and return the new source_file.
+/// add the path to the session's `source_map` and return the new `source_file`.
 fn file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
                    -> Lrc<SourceFile> {
     match try_file_to_source_file(sess, path, spanopt) {
@@ -264,37 +250,56 @@ fn file_to_source_file(sess: &ParseSess, path: &Path, spanopt: Option<Span>)
     }
 }
 
-/// Given a source_file, produce a sequence of token-trees
-pub fn source_file_to_stream(sess: &ParseSess,
-                             source_file: Lrc<SourceFile>,
-                             override_span: Option<Span>) -> TokenStream {
+/// Given a source_file, produces a sequence of token trees.
+pub fn source_file_to_stream(
+    sess: &ParseSess,
+    source_file: Lrc<SourceFile>,
+    override_span: Option<Span>,
+) -> (TokenStream, Vec<lexer::UnmatchedBrace>) {
     panictry_buffer!(&sess.span_diagnostic, maybe_file_to_stream(sess, source_file, override_span))
 }
 
-/// Given a source file, produce a sequence of token-trees. Returns any buffered errors from
+/// Given a source file, produces a sequence of token trees. Returns any buffered errors from
 /// parsing the token tream.
-pub fn maybe_file_to_stream(sess: &ParseSess,
-                            source_file: Lrc<SourceFile>,
-                            override_span: Option<Span>) -> Result<TokenStream, Vec<Diagnostic>> {
+pub fn maybe_file_to_stream(
+    sess: &ParseSess,
+    source_file: Lrc<SourceFile>,
+    override_span: Option<Span>,
+) -> Result<(TokenStream, Vec<lexer::UnmatchedBrace>), Vec<Diagnostic>> {
     let mut srdr = lexer::StringReader::new_or_buffered_errs(sess, source_file, override_span)?;
     srdr.real_token();
 
     match srdr.parse_all_token_trees() {
-        Ok(stream) => Ok(stream),
+        Ok(stream) => Ok((stream, srdr.unmatched_braces)),
         Err(err) => {
             let mut buffer = Vec::with_capacity(1);
             err.buffer(&mut buffer);
+            // Not using `emit_unclosed_delims` to use `db.buffer`
+            for unmatched in srdr.unmatched_braces {
+                let mut db = sess.span_diagnostic.struct_span_err(unmatched.found_span, &format!(
+                    "incorrect close delimiter: `{}`",
+                    token_to_string(&token::Token::CloseDelim(unmatched.found_delim)),
+                ));
+                db.span_label(unmatched.found_span, "incorrect close delimiter");
+                if let Some(sp) = unmatched.candidate_span {
+                    db.span_label(sp, "close delimiter possibly meant for this");
+                }
+                if let Some(sp) = unmatched.unclosed_span {
+                    db.span_label(sp, "un-closed delimiter");
+                }
+                db.buffer(&mut buffer);
+            }
             Err(buffer)
         }
     }
 }
 
-/// Given stream and the `ParseSess`, produce a parser
-pub fn stream_to_parser(sess: &ParseSess, stream: TokenStream) -> Parser {
+/// Given stream and the `ParseSess`, produces a parser.
+pub fn stream_to_parser(sess: &ParseSess, stream: TokenStream) -> Parser<'_> {
     Parser::new(sess, stream, None, true, false)
 }
 
-/// Parse a string representing a character literal into its final form.
+/// Parses a string representing a character literal into its final form.
 /// Rather than just accepting/rejecting a given literal, unescapes it as
 /// well. Can take any slice prefixed by a character escape. Returns the
 /// character and the number of characters consumed.
@@ -353,15 +358,14 @@ fn char_lit(lit: &str, diag: Option<(Span, &Handler)>) -> (char, isize) {
     }
 }
 
-/// Parse a string representing a string literal into its final form. Does
-/// unescaping.
+/// Parses a string representing a string literal into its final form. Does unescaping.
 pub fn str_lit(lit: &str, diag: Option<(Span, &Handler)>) -> String {
     debug!("str_lit: given {}", lit.escape_default());
     let mut res = String::with_capacity(lit.len());
 
     let error = |i| format!("lexer should have rejected {} at {}", lit, i);
 
-    /// Eat everything up to a non-whitespace
+    /// Eat everything up to a non-whitespace.
     fn eat<'a>(it: &mut iter::Peekable<str::CharIndices<'a>>) {
         loop {
             match it.peek().map(|x| x.1) {
@@ -422,7 +426,7 @@ pub fn str_lit(lit: &str, diag: Option<(Span, &Handler)>) -> String {
     res
 }
 
-/// Parse a string representing a raw string literal into its final form. The
+/// Parses a string representing a raw string literal into its final form. The
 /// only operation this does is convert embedded CRLF into a single LF.
 fn raw_str_lit(lit: &str) -> String {
     debug!("raw_str_lit: given {}", lit.escape_default());
@@ -466,6 +470,7 @@ crate fn lit_token(lit: token::Lit, suf: Option<Symbol>, diag: Option<(Span, &Ha
     match lit {
        token::Byte(i) => (true, Some(LitKind::Byte(byte_lit(&i.as_str()).0))),
        token::Char(i) => (true, Some(LitKind::Char(char_lit(&i.as_str(), diag).0))),
+       token::Err(i) => (true, Some(LitKind::Err(i))),
 
         // There are some valid suffixes for integer and float literals,
         // so all the handling is done internally.
@@ -547,7 +552,7 @@ fn float_lit(s: &str, suffix: Option<Symbol>, diag: Option<(Span, &Handler)>)
     filtered_float_lit(Symbol::intern(s), suffix, diag)
 }
 
-/// Parse a string representing a byte literal into its final form. Similar to `char_lit`
+/// Parses a string representing a byte literal into its final form. Similar to `char_lit`.
 fn byte_lit(lit: &str) -> (u8, usize) {
     let err = |i| format!("lexer accepted invalid byte literal {} step {}", lit, i);
 
@@ -584,7 +589,7 @@ fn byte_str_lit(lit: &str) -> Lrc<Vec<u8>> {
 
     let error = |i| panic!("lexer should have rejected {} at {}", lit, i);
 
-    /// Eat everything up to a non-whitespace
+    /// Eat everything up to a non-whitespace.
     fn eat<I: Iterator<Item=(usize, u8)>>(it: &mut iter::Peekable<I>) {
         loop {
             match it.peek().map(|x| x.1) {
@@ -751,10 +756,11 @@ fn integer_lit(s: &str, suffix: Option<Symbol>, diag: Option<(Span, &Handler)>)
     })
 }
 
-/// `SeqSep` : a sequence separator (token)
-/// and whether a trailing separator is allowed.
+/// A sequence separator.
 pub struct SeqSep {
+    /// The seperator token.
     pub sep: Option<token::Token>,
+    /// `true` if a trailing separator is allowed.
     pub trailing_sep_allowed: bool,
 }
 
@@ -777,15 +783,24 @@ impl SeqSep {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::ast::{self, Ident, PatKind};
+    use crate::attr::first_attr_value_str_by_name;
+    use crate::ptr::P;
+    use crate::print::pprust::item_to_string;
+    use crate::tokenstream::{DelimSpan, TokenTree};
+    use crate::util::parser_testing::string_to_stream;
+    use crate::util::parser_testing::{string_to_expr, string_to_item};
+    use crate::with_globals;
     use syntax_pos::{Span, BytePos, Pos, NO_EXPANSION};
-    use ast::{self, Ident, PatKind};
-    use attr::first_attr_value_str_by_name;
-    use parse;
-    use print::pprust::item_to_string;
-    use tokenstream::{DelimSpan, TokenTree};
-    use util::parser_testing::string_to_stream;
-    use util::parser_testing::{string_to_expr, string_to_item};
-    use with_globals;
+
+    /// Parses an item.
+    ///
+    /// Returns `Ok(Some(item))` when successful, `Ok(None)` when no item was found, and `Err`
+    /// when a syntax error occurred.
+    fn parse_item_from_source_str(name: FileName, source: String, sess: &ParseSess)
+                                        -> PResult<'_, Option<P<ast::Item>>> {
+        new_parser_from_source_str(sess, name, source).parse_item()
+    }
 
     // produce a syntax_pos::span
     fn sp(a: u32, b: u32) -> Span {
@@ -817,7 +832,7 @@ mod tests {
                 )
                 if name_macro_rules.name == "macro_rules"
                 && name_zip.name == "zip" => {
-                    let tts = &macro_tts.stream().trees().collect::<Vec<_>>();
+                    let tts = &macro_tts.trees().collect::<Vec<_>>();
                     match (tts.len(), tts.get(0), tts.get(1), tts.get(2)) {
                         (
                             3,
@@ -826,7 +841,7 @@ mod tests {
                             Some(&TokenTree::Delimited(_, second_delim, ref second_tts)),
                         )
                         if macro_delim == token::Paren => {
-                            let tts = &first_tts.stream().trees().collect::<Vec<_>>();
+                            let tts = &first_tts.trees().collect::<Vec<_>>();
                             match (tts.len(), tts.get(0), tts.get(1)) {
                                 (
                                     2,
@@ -836,7 +851,7 @@ mod tests {
                                 if first_delim == token::Paren && ident.name == "a" => {},
                                 _ => panic!("value 3: {:?} {:?}", first_delim, first_tts),
                             }
-                            let tts = &second_tts.stream().trees().collect::<Vec<_>>();
+                            let tts = &second_tts.trees().collect::<Vec<_>>();
                             match (tts.len(), tts.get(0), tts.get(1)) {
                                 (
                                     2,
@@ -923,20 +938,20 @@ mod tests {
         struct PatIdentVisitor {
             spans: Vec<Span>
         }
-        impl<'a> ::visit::Visitor<'a> for PatIdentVisitor {
+        impl<'a> crate::visit::Visitor<'a> for PatIdentVisitor {
             fn visit_pat(&mut self, p: &'a ast::Pat) {
                 match p.node {
                     PatKind::Ident(_ , ref spannedident, _) => {
                         self.spans.push(spannedident.span.clone());
                     }
                     _ => {
-                        ::visit::walk_pat(self, p);
+                        crate::visit::walk_pat(self, p);
                     }
                 }
             }
         }
         let mut v = PatIdentVisitor { spans: Vec::new() };
-        ::visit::walk_item(&mut v, &item);
+        crate::visit::walk_item(&mut v, &item);
         return v.spans;
     }
 
@@ -1015,9 +1030,15 @@ mod tests {
 
     #[test]
     fn ttdelim_span() {
+        fn parse_expr_from_source_str(
+            name: FileName, source: String, sess: &ParseSess
+        ) -> PResult<'_, P<ast::Expr>> {
+            new_parser_from_source_str(sess, name, source).parse_expr()
+        }
+
         with_globals(|| {
             let sess = ParseSess::new(FilePathMapping::empty());
-            let expr = parse::parse_expr_from_source_str(PathBuf::from("foo").into(),
+            let expr = parse_expr_from_source_str(PathBuf::from("foo").into(),
                 "foo!( fn main() { body } )".to_string(), &sess).unwrap();
 
             let tts: Vec<_> = match expr.node {
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 823c786bded26..e6a48912c48b4 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1,53 +1,55 @@
+use crate::ast::{AngleBracketedArgs, ParenthesizedArgs, AttrStyle, BareFnTy};
+use crate::ast::{GenericBound, TraitBoundModifier};
+use crate::ast::Unsafety;
+use crate::ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind};
+use crate::ast::Block;
+use crate::ast::{BlockCheckMode, CaptureBy, Movability};
+use crate::ast::{Constness, Crate};
+use crate::ast::Defaultness;
+use crate::ast::EnumDef;
+use crate::ast::{Expr, ExprKind, RangeLimits};
+use crate::ast::{Field, FnDecl, FnHeader};
+use crate::ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
+use crate::ast::{GenericParam, GenericParamKind};
+use crate::ast::GenericArg;
+use crate::ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind};
+use crate::ast::{Label, Lifetime, Lit, LitKind};
+use crate::ast::Local;
+use crate::ast::MacStmtStyle;
+use crate::ast::{Mac, Mac_, MacDelimiter};
+use crate::ast::{MutTy, Mutability};
+use crate::ast::{Pat, PatKind, PathSegment};
+use crate::ast::{PolyTraitRef, QSelf};
+use crate::ast::{Stmt, StmtKind};
+use crate::ast::{VariantData, StructField};
+use crate::ast::StrStyle;
+use crate::ast::SelfKind;
+use crate::ast::{TraitItem, TraitRef, TraitObjectSyntax};
+use crate::ast::{Ty, TyKind, TypeBinding, GenericBounds};
+use crate::ast::{Visibility, VisibilityKind, WhereClause, CrateSugar};
+use crate::ast::{UseTree, UseTreeKind};
+use crate::ast::{BinOpKind, UnOp};
+use crate::ast::{RangeEnd, RangeSyntax};
+use crate::{ast, attr};
+use crate::ext::base::DummyResult;
+use crate::source_map::{self, SourceMap, Spanned, respan};
+use crate::parse::{self, SeqSep, classify, token};
+use crate::parse::lexer::{TokenAndSpan, UnmatchedBrace};
+use crate::parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
+use crate::parse::token::DelimToken;
+use crate::parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership};
+use crate::util::parser::{AssocOp, Fixity};
+use crate::print::pprust;
+use crate::ptr::P;
+use crate::parse::PResult;
+use crate::ThinVec;
+use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
+use crate::symbol::{Symbol, keywords};
+
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
 use rustc_target::spec::abi::{self, Abi};
-use ast::{AngleBracketedArgs, ParenthesisedArgs, AttrStyle, BareFnTy};
-use ast::{GenericBound, TraitBoundModifier};
-use ast::Unsafety;
-use ast::{Mod, AnonConst, Arg, Arm, Guard, Attribute, BindingMode, TraitItemKind};
-use ast::Block;
-use ast::{BlockCheckMode, CaptureBy, Movability};
-use ast::{Constness, Crate};
-use ast::Defaultness;
-use ast::EnumDef;
-use ast::{Expr, ExprKind, RangeLimits};
-use ast::{Field, FnDecl, FnHeader};
-use ast::{ForeignItem, ForeignItemKind, FunctionRetTy};
-use ast::{GenericParam, GenericParamKind};
-use ast::GenericArg;
-use ast::{Ident, ImplItem, IsAsync, IsAuto, Item, ItemKind};
-use ast::{Label, Lifetime, Lit, LitKind};
-use ast::Local;
-use ast::MacStmtStyle;
-use ast::{Mac, Mac_, MacDelimiter};
-use ast::{MutTy, Mutability};
-use ast::{Pat, PatKind, PathSegment};
-use ast::{PolyTraitRef, QSelf};
-use ast::{Stmt, StmtKind};
-use ast::{VariantData, StructField};
-use ast::StrStyle;
-use ast::SelfKind;
-use ast::{TraitItem, TraitRef, TraitObjectSyntax};
-use ast::{Ty, TyKind, TypeBinding, GenericBounds};
-use ast::{Visibility, VisibilityKind, WhereClause, CrateSugar};
-use ast::{UseTree, UseTreeKind};
-use ast::{BinOpKind, UnOp};
-use ast::{RangeEnd, RangeSyntax};
-use {ast, attr};
-use ext::base::DummyResult;
-use source_map::{self, SourceMap, Spanned, respan};
-use syntax_pos::{self, Span, MultiSpan, BytePos, FileName};
-use errors::{self, Applicability, DiagnosticBuilder, DiagnosticId};
-use parse::{self, SeqSep, classify, token};
-use parse::lexer::TokenAndSpan;
-use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
-use parse::token::DelimToken;
-use parse::{new_sub_parser_from_file, ParseSess, Directory, DirectoryOwnership};
-use util::parser::{AssocOp, Fixity};
-use print::pprust;
-use ptr::P;
-use parse::PResult;
-use ThinVec;
-use tokenstream::{self, DelimSpan, ThinTokenStream, TokenTree, TokenStream};
-use symbol::{Symbol, keywords};
+use syntax_pos::{Span, MultiSpan, BytePos, FileName};
+use log::{debug, trace};
 
 use std::borrow::Cow;
 use std::cmp;
@@ -64,7 +66,7 @@ pub enum AliasKind {
     Existential(GenericBounds),
 }
 
-bitflags! {
+bitflags::bitflags! {
     struct Restrictions: u8 {
         const STMT_EXPR         = 1 << 0;
         const NO_STRUCT_LITERAL = 1 << 1;
@@ -73,7 +75,7 @@ bitflags! {
 
 type ItemInfo = (Ident, ItemKind, Option<Vec<Attribute>>);
 
-/// How to parse a path.
+/// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
 pub enum PathStyle {
     /// In some contexts, notably in expressions, paths with generic arguments are ambiguous
@@ -100,6 +102,7 @@ pub enum PathStyle {
 enum SemiColonMode {
     Break,
     Ignore,
+    Comma,
 }
 
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -108,7 +111,7 @@ enum BlockMode {
     Ignore,
 }
 
-/// Possibly accept an `token::Interpolated` expression (a pre-parsed expression
+/// Possibly accepts an `token::Interpolated` expression (a pre-parsed expression
 /// dropped into the token stream, which happens while parsing the result of
 /// macro expansion). Placement of these is not as complex as I feared it would
 /// be. The important thing is to make sure that lookahead doesn't balk at
@@ -242,6 +245,17 @@ pub struct Parser<'a> {
     desugar_doc_comments: bool,
     /// Whether we should configure out of line modules as we parse.
     pub cfg_mods: bool,
+    /// This field is used to keep track of how many left angle brackets we have seen. This is
+    /// required in order to detect extra leading left angle brackets (`<` characters) and error
+    /// appropriately.
+    ///
+    /// See the comments in the `parse_path_segment` function for more details.
+    crate unmatched_angle_bracket_count: u32,
+    crate max_angle_bracket_count: u32,
+    /// List of all unclosed delimiters found by the lexer. If an entry is used for error recovery
+    /// it gets removed from here. Every entry left at the end gets emitted as an independent
+    /// error.
+    crate unclosed_delims: Vec<UnmatchedBrace>,
 }
 
 
@@ -280,17 +294,17 @@ struct TokenCursorFrame {
 /// on the parser.
 #[derive(Clone)]
 enum LastToken {
-    Collecting(Vec<TokenStream>),
-    Was(Option<TokenStream>),
+    Collecting(Vec<TreeAndJoint>),
+    Was(Option<TreeAndJoint>),
 }
 
 impl TokenCursorFrame {
-    fn new(sp: DelimSpan, delim: DelimToken, tts: &ThinTokenStream) -> Self {
+    fn new(sp: DelimSpan, delim: DelimToken, tts: &TokenStream) -> Self {
         TokenCursorFrame {
             delim: delim,
             span: sp,
             open_delim: delim == token::NoDelim,
-            tree_cursor: tts.stream().into_trees(),
+            tree_cursor: tts.clone().into_trees(),
             close_delim: delim == token::NoDelim,
             last_token: LastToken::Was(None),
         }
@@ -388,6 +402,7 @@ crate enum TokenType {
     Ident,
     Path,
     Type,
+    Const,
 }
 
 impl TokenType {
@@ -400,15 +415,16 @@ impl TokenType {
             TokenType::Ident => "identifier".to_string(),
             TokenType::Path => "path".to_string(),
             TokenType::Type => "type".to_string(),
+            TokenType::Const => "const".to_string(),
         }
     }
 }
 
-/// Returns true if `IDENT t` can start a type - `IDENT::a::b`, `IDENT<u8, u8>`,
+/// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
 /// `IDENT<<u8 as Trait>::AssocTy>`.
 ///
 /// Types can also be of the form `IDENT(u8, u8) -> u8`, however this assumes
-/// that IDENT is not the ident of a fn trait
+/// that `IDENT` is not the ident of a fn trait.
 fn can_continue_type_after_non_fn_ident(t: &token::Token) -> bool {
     t == &token::ModSep || t == &token::Lt ||
     t == &token::BinOp(token::Shl)
@@ -446,7 +462,7 @@ pub enum Error {
 impl Error {
     fn span_err<S: Into<MultiSpan>>(self,
                                         sp: S,
-                                        handler: &errors::Handler) -> DiagnosticBuilder {
+                                        handler: &errors::Handler) -> DiagnosticBuilder<'_> {
         match self {
             Error::FileNotFoundForModule { ref mod_name,
                                            ref default_path,
@@ -509,7 +525,7 @@ impl From<P<Expr>> for LhsExpr {
     }
 }
 
-/// Create a placeholder argument.
+/// Creates a placeholder argument.
 fn dummy_arg(span: Span) -> Arg {
     let ident = Ident::new(keywords::Invalid.name(), span);
     let pat = P(Pat {
@@ -563,6 +579,9 @@ impl<'a> Parser<'a> {
             },
             desugar_doc_comments,
             cfg_mods: true,
+            unmatched_angle_bracket_count: 0,
+            max_angle_bracket_count: 0,
+            unclosed_delims: Vec::new(),
         };
 
         let tok = parser.next_tok();
@@ -595,7 +614,7 @@ impl<'a> Parser<'a> {
         next
     }
 
-    /// Convert the current token to a string using self's reader
+    /// Converts the current token to a string using `self`'s reader.
     pub fn this_token_to_string(&self) -> String {
         pprust::token_to_string(&self.token)
     }
@@ -630,13 +649,12 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Expect and consume the token t. Signal an error if
-    /// the next token is not t.
-    pub fn expect(&mut self, t: &token::Token) -> PResult<'a,  ()> {
+    /// Expects and consumes the token `t`. Signals an error if the next token is not `t`.
+    pub fn expect(&mut self, t: &token::Token) -> PResult<'a,  bool /* recovered */> {
         if self.expected_tokens.is_empty() {
             if self.token == *t {
                 self.bump();
-                Ok(())
+                Ok(false)
             } else {
                 let token_str = pprust::token_to_string(t);
                 let this_token_str = self.this_token_descr();
@@ -651,6 +669,12 @@ impl<'a> Parser<'a> {
                     self.sess.source_map().next_point(self.prev_span)
                 };
                 let label_exp = format!("expected `{}`", token_str);
+                match self.recover_closing_delimiter(&[t.clone()], err) {
+                    Err(e) => err = e,
+                    Ok(recovered) => {
+                        return Ok(recovered);
+                    }
+                }
                 let cm = self.sess.source_map();
                 match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) {
                     (Ok(ref a), Ok(ref b)) if a.line == b.line => {
@@ -670,12 +694,64 @@ impl<'a> Parser<'a> {
         }
     }
 
+    fn recover_closing_delimiter(
+        &mut self,
+        tokens: &[token::Token],
+        mut err: DiagnosticBuilder<'a>,
+    ) -> PResult<'a, bool> {
+        let mut pos = None;
+        // we want to use the last closing delim that would apply
+        for (i, unmatched) in self.unclosed_delims.iter().enumerate().rev() {
+            if tokens.contains(&token::CloseDelim(unmatched.expected_delim))
+                && Some(self.span) > unmatched.unclosed_span
+            {
+                pos = Some(i);
+            }
+        }
+        match pos {
+            Some(pos) => {
+                // Recover and assume that the detected unclosed delimiter was meant for
+                // this location. Emit the diagnostic and act as if the delimiter was
+                // present for the parser's sake.
+
+                 // Don't attempt to recover from this unclosed delimiter more than once.
+                let unmatched = self.unclosed_delims.remove(pos);
+                let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim));
+
+                 // We want to suggest the inclusion of the closing delimiter where it makes
+                // the most sense, which is immediately after the last token:
+                //
+                //  {foo(bar {}}
+                //      -      ^
+                //      |      |
+                //      |      help: `)` may belong here (FIXME: #58270)
+                //      |
+                //      unclosed delimiter
+                if let Some(sp) = unmatched.unclosed_span {
+                    err.span_label(sp, "unclosed delimiter");
+                }
+                err.span_suggestion_short(
+                    self.sess.source_map().next_point(self.prev_span),
+                    &format!("{} may belong here", delim.to_string()),
+                    delim.to_string(),
+                    Applicability::MaybeIncorrect,
+                );
+                err.emit();
+                self.expected_tokens.clear();  // reduce errors
+                Ok(true)
+            }
+            _ => Err(err),
+        }
+    }
+
     /// Expect next token to be edible or inedible token.  If edible,
     /// then consume it; if inedible, then return without consuming
     /// anything.  Signal a fatal error if next token is unexpected.
-    pub fn expect_one_of(&mut self,
-                         edible: &[token::Token],
-                         inedible: &[token::Token]) -> PResult<'a,  ()>{
+    pub fn expect_one_of(
+        &mut self,
+        edible: &[token::Token],
+        inedible: &[token::Token],
+    ) -> PResult<'a, bool /* recovered */> {
         fn tokens_to_string(tokens: &[TokenType]) -> String {
             let mut i = tokens.iter();
             // This might be a sign we need a connect method on Iterator.
@@ -695,10 +771,10 @@ impl<'a> Parser<'a> {
         }
         if edible.contains(&self.token) {
             self.bump();
-            Ok(())
+            Ok(false)
         } else if inedible.contains(&self.token) {
             // leave it in the input
-            Ok(())
+            Ok(false)
         } else {
             let mut expected = edible.iter()
                 .map(|x| TokenType::Token(x.clone()))
@@ -728,7 +804,7 @@ impl<'a> Parser<'a> {
             };
             let mut err = self.fatal(&msg_exp);
             if self.token.is_ident_named("and") {
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     self.span,
                     "use `&&` instead of `and` for the boolean operator",
                     "&&".to_string(),
@@ -736,7 +812,7 @@ impl<'a> Parser<'a> {
                 );
             }
             if self.token.is_ident_named("or") {
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     self.span,
                     "use `||` instead of `or` for the boolean operator",
                     "||".to_string(),
@@ -749,6 +825,15 @@ impl<'a> Parser<'a> {
             } else {
                 label_sp
             };
+            match self.recover_closing_delimiter(&expected.iter().filter_map(|tt| match tt {
+                TokenType::Token(t) => Some(t.clone()),
+                _ => None,
+            }).collect::<Vec<_>>(), err) {
+                Err(e) => err = e,
+                Ok(recovered) => {
+                    return Ok(recovered);
+                }
+            }
 
             let cm = self.sess.source_map();
             match (cm.lookup_line(self.span.lo()), cm.lookup_line(sp.lo())) {
@@ -781,7 +866,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// returns the span of expr, if it was not interpolated or the span of the interpolated token
+    /// Returns the span of expr, if it was not interpolated or the span of the interpolated token.
     fn interpolated_or_expr_span(&self,
                                  expr: PResult<'a, P<Expr>>)
                                  -> PResult<'a, (Span, P<Expr>)> {
@@ -802,7 +887,7 @@ impl<'a> Parser<'a> {
             if ident.is_reserved() && !ident.is_path_segment_keyword() &&
                 ident.name != keywords::Underscore.name()
             {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     self.span,
                     "you can escape reserved keywords to use them as identifiers",
                     format!("r#{}", ident),
@@ -815,7 +900,7 @@ impl<'a> Parser<'a> {
         } else {
             err.span_label(self.span, "expected identifier");
             if self.token == token::Comma && self.look_ahead(1, |t| t.is_ident()) {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     self.span,
                     "remove this comma",
                     String::new(),
@@ -855,7 +940,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Check if the next token is `tok`, and return `true` if so.
+    /// Checks if the next token is `tok`, and returns `true` if so.
     ///
     /// This method will automatically add `tok` to `expected_tokens` if `tok` is not
     /// encountered.
@@ -865,8 +950,7 @@ impl<'a> Parser<'a> {
         is_present
     }
 
-    /// Consume token 'tok' if it exists. Returns true if the given
-    /// token was present, false otherwise.
+    /// Consumes a token 'tok' if it exists. Returns whether the given token was present.
     pub fn eat(&mut self, tok: &token::Token) -> bool {
         let is_present = self.check(tok);
         if is_present { self.bump() }
@@ -878,8 +962,8 @@ impl<'a> Parser<'a> {
         self.token.is_keyword(kw)
     }
 
-    /// If the next token is the given keyword, eat it and return
-    /// true. Otherwise, return false.
+    /// If the next token is the given keyword, eats it and returns
+    /// `true`. Otherwise, returns `false`.
     pub fn eat_keyword(&mut self, kw: keywords::Keyword) -> bool {
         if self.check_keyword(kw) {
             self.bump();
@@ -898,9 +982,9 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// If the given word is not a keyword, signal an error.
-    /// If the next token is not the given word, signal an error.
-    /// Otherwise, eat it.
+    /// If the given word is not a keyword, signals an error.
+    /// If the next token is not the given word, signals an error.
+    /// Otherwise, eats it.
     fn expect_keyword(&mut self, kw: keywords::Keyword) -> PResult<'a, ()> {
         if !self.eat_keyword(kw) {
             self.unexpected()
@@ -936,11 +1020,20 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Expect and consume a `+`. if `+=` is seen, replace it with a `=`
-    /// and continue. If a `+` is not seen, return false.
+    fn check_const_arg(&mut self) -> bool {
+        if self.token.can_begin_const_arg() {
+            true
+        } else {
+            self.expected_tokens.push(TokenType::Const);
+            false
+        }
+    }
+
+    /// Expects and consumes a `+`. if `+=` is seen, replaces it with a `=`
+    /// and continues. If a `+` is not seen, returns `false`.
     ///
-    /// This is using when token splitting += into +.
-    /// See issue 47856 for an example of when this may occur.
+    /// This is used when token-splitting `+=` into `+`.
+    /// See issue #47856 for an example of when this may occur.
     fn eat_plus(&mut self) -> bool {
         self.expected_tokens.push(TokenType::Token(token::BinOp(token::Plus)));
         match self.token {
@@ -959,7 +1052,7 @@ impl<'a> Parser<'a> {
 
 
     /// Checks to see if the next token is either `+` or `+=`.
-    /// Otherwise returns false.
+    /// Otherwise returns `false`.
     fn check_plus(&mut self) -> bool {
         if self.token.is_like_plus() {
             true
@@ -970,8 +1063,8 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Expect and consume an `&`. If `&&` is seen, replace it with a single
-    /// `&` and continue. If an `&` is not seen, signal an error.
+    /// Expects and consumes an `&`. If `&&` is seen, replaces it with a single
+    /// `&` and continues. If an `&` is not seen, signals an error.
     fn expect_and(&mut self) -> PResult<'a, ()> {
         self.expected_tokens.push(TokenType::Token(token::BinOp(token::And)));
         match self.token {
@@ -987,8 +1080,8 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Expect and consume an `|`. If `||` is seen, replace it with a single
-    /// `|` and continue. If an `|` is not seen, signal an error.
+    /// Expects and consumes an `|`. If `||` is seen, replaces it with a single
+    /// `|` and continues. If an `|` is not seen, signals an error.
     fn expect_or(&mut self) -> PResult<'a, ()> {
         self.expected_tokens.push(TokenType::Token(token::BinOp(token::Or)));
         match self.token {
@@ -1020,14 +1113,15 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
-    /// `<` and continue. If a `<` is not seen, return false.
+    /// Attempts to consume a `<`. If `<<` is seen, replaces it with a single
+    /// `<` and continue. If `<-` is seen, replaces it with a single `<`
+    /// and continue. If a `<` is not seen, returns false.
     ///
     /// This is meant to be used when parsing generics on a path to get the
     /// starting token.
     fn eat_lt(&mut self) -> bool {
         self.expected_tokens.push(TokenType::Token(token::Lt));
-        match self.token {
+        let ate = match self.token {
             token::Lt => {
                 self.bump();
                 true
@@ -1037,8 +1131,22 @@ impl<'a> Parser<'a> {
                 self.bump_with(token::Lt, span);
                 true
             }
+            token::LArrow => {
+                let span = self.span.with_lo(self.span.lo() + BytePos(1));
+                self.bump_with(token::BinOp(token::Minus), span);
+                true
+            }
             _ => false,
+        };
+
+        if ate {
+            // See doc comment for `unmatched_angle_bracket_count`.
+            self.unmatched_angle_bracket_count += 1;
+            self.max_angle_bracket_count += 1;
+            debug!("eat_lt: (increment) count={:?}", self.unmatched_angle_bracket_count);
         }
+
+        ate
     }
 
     fn expect_lt(&mut self) -> PResult<'a, ()> {
@@ -1049,33 +1157,43 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Expect and consume a GT. if a >> is seen, replace it
-    /// with a single > and continue. If a GT is not seen,
-    /// signal an error.
+    /// Expects and consumes a single `>` token. if a `>>` is seen, replaces it
+    /// with a single `>` and continues. If a `>` is not seen, signals an error.
     fn expect_gt(&mut self) -> PResult<'a, ()> {
         self.expected_tokens.push(TokenType::Token(token::Gt));
-        match self.token {
+        let ate = match self.token {
             token::Gt => {
                 self.bump();
-                Ok(())
+                Some(())
             }
             token::BinOp(token::Shr) => {
                 let span = self.span.with_lo(self.span.lo() + BytePos(1));
-                Ok(self.bump_with(token::Gt, span))
+                Some(self.bump_with(token::Gt, span))
             }
             token::BinOpEq(token::Shr) => {
                 let span = self.span.with_lo(self.span.lo() + BytePos(1));
-                Ok(self.bump_with(token::Ge, span))
+                Some(self.bump_with(token::Ge, span))
             }
             token::Ge => {
                 let span = self.span.with_lo(self.span.lo() + BytePos(1));
-                Ok(self.bump_with(token::Eq, span))
+                Some(self.bump_with(token::Eq, span))
             }
-            _ => self.unexpected()
+            _ => None,
+        };
+
+        match ate {
+            Some(_) => {
+                // See doc comment for `unmatched_angle_bracket_count`.
+                self.unmatched_angle_bracket_count -= 1;
+                debug!("expect_gt: (decrement) count={:?}", self.unmatched_angle_bracket_count);
+
+                Ok(())
+            },
+            None => self.unexpected(),
         }
     }
 
-    /// Eat and discard tokens until one of `kets` is encountered. Respects token trees,
+    /// Eats and discards tokens until one of `kets` is encountered. Respects token trees,
     /// passes through any errors encountered. Used for error recovery.
     fn eat_to_tokens(&mut self, kets: &[&token::Token]) {
         let handler = self.diagnostic();
@@ -1088,8 +1206,8 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse a sequence, including the closing delimiter. The function
-    /// f must consume tokens until reaching the next separator or
+    /// Parses a sequence, including the closing delimiter. The function
+    /// `f` must consume tokens until reaching the next separator or
     /// closing bracket.
     pub fn parse_seq_to_end<T, F>(&mut self,
                                   ket: &token::Token,
@@ -1098,19 +1216,22 @@ impl<'a> Parser<'a> {
                                   -> PResult<'a, Vec<T>> where
         F: FnMut(&mut Parser<'a>) -> PResult<'a,  T>,
     {
-        let val = self.parse_seq_to_before_end(ket, sep, f)?;
-        self.bump();
+        let (val, recovered) = self.parse_seq_to_before_end(ket, sep, f)?;
+        if !recovered {
+            self.bump();
+        }
         Ok(val)
     }
 
-    /// Parse a sequence, not including the closing delimiter. The function
-    /// f must consume tokens until reaching the next separator or
+    /// Parses a sequence, not including the closing delimiter. The function
+    /// `f` must consume tokens until reaching the next separator or
     /// closing bracket.
-    pub fn parse_seq_to_before_end<T, F>(&mut self,
-                                         ket: &token::Token,
-                                         sep: SeqSep,
-                                         f: F)
-                                         -> PResult<'a, Vec<T>>
+    pub fn parse_seq_to_before_end<T, F>(
+        &mut self,
+        ket: &token::Token,
+        sep: SeqSep,
+        f: F,
+    ) -> PResult<'a, (Vec<T>, bool)>
         where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>
     {
         self.parse_seq_to_before_tokens(&[ket], sep, TokenExpectType::Expect, f)
@@ -1122,10 +1243,11 @@ impl<'a> Parser<'a> {
         sep: SeqSep,
         expect: TokenExpectType,
         mut f: F,
-    ) -> PResult<'a, Vec<T>>
+    ) -> PResult<'a, (Vec<T>, bool /* recovered */)>
         where F: FnMut(&mut Parser<'a>) -> PResult<'a, T>
     {
-        let mut first: bool = true;
+        let mut first = true;
+        let mut recovered = false;
         let mut v = vec![];
         while !kets.iter().any(|k| {
                 match expect {
@@ -1141,23 +1263,30 @@ impl<'a> Parser<'a> {
                 if first {
                     first = false;
                 } else {
-                    if let Err(mut e) = self.expect(t) {
-                        // Attempt to keep parsing if it was a similar separator
-                        if let Some(ref tokens) = t.similar_tokens() {
-                            if tokens.contains(&self.token) {
-                                self.bump();
-                            }
+                    match self.expect(t) {
+                        Ok(false) => {}
+                        Ok(true) => {
+                            recovered = true;
+                            break;
                         }
-                        e.emit();
-                        // Attempt to keep parsing if it was an omitted separator
-                        match f(self) {
-                            Ok(t) => {
-                                v.push(t);
-                                continue;
-                            },
-                            Err(mut e) => {
-                                e.cancel();
-                                break;
+                        Err(mut e) => {
+                            // Attempt to keep parsing if it was a similar separator
+                            if let Some(ref tokens) = t.similar_tokens() {
+                                if tokens.contains(&self.token) {
+                                    self.bump();
+                                }
+                            }
+                            e.emit();
+                            // Attempt to keep parsing if it was an omitted separator
+                            match f(self) {
+                                Ok(t) => {
+                                    v.push(t);
+                                    continue;
+                                },
+                                Err(mut e) => {
+                                    e.cancel();
+                                    break;
+                                }
                             }
                         }
                     }
@@ -1176,23 +1305,26 @@ impl<'a> Parser<'a> {
             v.push(t);
         }
 
-        Ok(v)
+        Ok((v, recovered))
     }
 
-    /// Parse a sequence, including the closing delimiter. The function
-    /// f must consume tokens until reaching the next separator or
+    /// Parses a sequence, including the closing delimiter. The function
+    /// `f` must consume tokens until reaching the next separator or
     /// closing bracket.
-    fn parse_unspanned_seq<T, F>(&mut self,
-                                     bra: &token::Token,
-                                     ket: &token::Token,
-                                     sep: SeqSep,
-                                     f: F)
-                                     -> PResult<'a, Vec<T>> where
+    fn parse_unspanned_seq<T, F>(
+        &mut self,
+        bra: &token::Token,
+        ket: &token::Token,
+        sep: SeqSep,
+        f: F,
+    ) -> PResult<'a, Vec<T>> where
         F: FnMut(&mut Parser<'a>) -> PResult<'a, T>,
     {
         self.expect(bra)?;
-        let result = self.parse_seq_to_before_end(ket, sep, f)?;
-        self.eat(ket);
+        let (result, recovered) = self.parse_seq_to_before_end(ket, sep, f)?;
+        if !recovered {
+            self.eat(ket);
+        }
         Ok(result)
     }
 
@@ -1285,11 +1417,8 @@ impl<'a> Parser<'a> {
     crate fn span_bug<S: Into<MultiSpan>>(&self, sp: S, m: &str) -> ! {
         self.sess.span_diagnostic.span_bug(sp, m)
     }
-    crate fn abort_if_errors(&self) {
-        self.sess.span_diagnostic.abort_if_errors();
-    }
 
-    fn cancel(&self, err: &mut DiagnosticBuilder) {
+    fn cancel(&self, err: &mut DiagnosticBuilder<'_>) {
         self.sess.span_diagnostic.cancel(err)
     }
 
@@ -1297,15 +1426,14 @@ impl<'a> Parser<'a> {
         &self.sess.span_diagnostic
     }
 
-    /// Is the current token one of the keywords that signals a bare function
-    /// type?
+    /// Is the current token one of the keywords that signals a bare function type?
     fn token_is_bare_fn_keyword(&mut self) -> bool {
         self.check_keyword(keywords::Fn) ||
             self.check_keyword(keywords::Unsafe) ||
             self.check_keyword(keywords::Extern)
     }
 
-    /// parse a `TyKind::BareFn` type:
+    /// Parses a `TyKind::BareFn` type.
     fn parse_ty_bare_fn(&mut self, generic_params: Vec<GenericParam>) -> PResult<'a, TyKind> {
         /*
 
@@ -1342,7 +1470,7 @@ impl<'a> Parser<'a> {
         })))
     }
 
-    /// Parse asyncness: `async` or nothing
+    /// Parses asyncness: `async` or nothing.
     fn parse_asyncness(&mut self) -> IsAsync {
         if self.eat_keyword(keywords::Async) {
             IsAsync::Async {
@@ -1354,7 +1482,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse unsafety: `unsafe` or nothing.
+    /// Parses unsafety: `unsafe` or nothing.
     fn parse_unsafety(&mut self) -> Unsafety {
         if self.eat_keyword(keywords::Unsafe) {
             Unsafety::Unsafe
@@ -1363,7 +1491,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse the items in a trait declaration
+    /// Parses the items in a trait declaration.
     pub fn parse_trait_item(&mut self, at_end: &mut bool) -> PResult<'a, TraitItem> {
         maybe_whole!(self, NtTraitItem, |x| x);
         let attrs = self.parse_outer_attributes()?;
@@ -1480,7 +1608,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse optional return type [ -> TY ] in function decl
+    /// Parses an optional return type `[ -> TY ]` in a function declaration.
     fn parse_ret_ty(&mut self, allow_plus: bool) -> PResult<'a, FunctionRetTy> {
         if self.eat(&token::RArrow) {
             Ok(FunctionRetTy::Ty(self.parse_ty_common(allow_plus, true)?))
@@ -1489,12 +1617,13 @@ impl<'a> Parser<'a> {
         }
     }
 
-    // Parse a type
+    /// Parses a type.
     pub fn parse_ty(&mut self) -> PResult<'a, P<Ty>> {
         self.parse_ty_common(true, true)
     }
 
-    /// Parse a type in restricted contexts where `+` is not permitted.
+    /// Parses a type in restricted contexts where `+` is not permitted.
+    ///
     /// Example 1: `&'a TYPE`
     ///     `+` is prohibited to maintain operator priority (P(+) < P(&)).
     /// Example 2: `value1 as TYPE + value2`
@@ -1672,7 +1801,7 @@ impl<'a> Parser<'a> {
         if !allow_plus && impl_dyn_multi {
             let sum_with_parens = format!("({})", pprust::ty_to_string(&ty));
             self.struct_span_err(ty.span, "ambiguous `+` in a type")
-                .span_suggestion_with_applicability(
+                .span_suggestion(
                     ty.span,
                     "use parentheses to disambiguate",
                     sum_with_parens,
@@ -1697,7 +1826,7 @@ impl<'a> Parser<'a> {
         match ty.node {
             TyKind::Rptr(ref lifetime, ref mut_ty) => {
                 let sum_with_parens = pprust::to_string(|s| {
-                    use print::pprust::PrintState;
+                    use crate::print::pprust::PrintState;
 
                     s.s.word("&")?;
                     s.print_opt_lifetime(lifetime)?;
@@ -1707,7 +1836,7 @@ impl<'a> Parser<'a> {
                     s.print_type_bounds(" +", &bounds)?;
                     s.pclose()
                 });
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     sum_span,
                     "try adding parentheses",
                     sum_with_parens,
@@ -1750,7 +1879,7 @@ impl<'a> Parser<'a> {
 
         self.diagnostic()
             .struct_span_err(span, "missing angle brackets in associated item path")
-            .span_suggestion_with_applicability( // this is a best-effort recovery
+            .span_suggestion( // this is a best-effort recovery
                 span, "try", recovered.to_string(), Applicability::MaybeIncorrect
             ).emit();
 
@@ -1797,7 +1926,8 @@ impl<'a> Parser<'a> {
         self.look_ahead(offset + 1, |t| t == &token::Colon)
     }
 
-    /// Skip unexpected attributes and doc comments in this position and emit an appropriate error.
+    /// Skips unexpected attributes and doc comments in this position and emits an appropriate
+    /// error.
     fn eat_incorrect_doc_comment(&mut self, applied_to: &str) {
         if let token::DocComment(_) = self.token {
             let mut err = self.diagnostic().struct_span_err(
@@ -1826,8 +1956,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// This version of parse arg doesn't necessarily require
-    /// identifier names.
+    /// This version of parse arg doesn't necessarily require identifier names.
     fn parse_arg_general(&mut self, require_name: bool, is_trait_item: bool) -> PResult<'a, Arg> {
         maybe_whole!(self, NtArg, |x| x);
 
@@ -1854,7 +1983,7 @@ impl<'a> Parser<'a> {
                     let ident = self.parse_ident().unwrap();
                     let span = pat.span.with_hi(ident.span.hi());
 
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         span,
                         "declare the type after the parameter binding",
                         String::from("<identifier>: <type>"),
@@ -1862,7 +1991,7 @@ impl<'a> Parser<'a> {
                     );
                 } else if require_name && is_trait_item {
                     if let PatKind::Ident(_, ident, _) = pat.node {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             pat.span,
                             "explicitly ignore parameter",
                             format!("_: {}", ident),
@@ -1913,7 +2042,7 @@ impl<'a> Parser<'a> {
                         "patterns aren't allowed in methods without bodies",
                         DiagnosticId::Error("E0642".into()),
                     );
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         pat.span,
                         "give this argument a name or use an underscore to ignore it",
                         "_".to_owned(),
@@ -1935,12 +2064,12 @@ impl<'a> Parser<'a> {
         Ok(Arg { ty, pat, id: ast::DUMMY_NODE_ID })
     }
 
-    /// Parse a single function argument
+    /// Parses a single function argument.
     crate fn parse_arg(&mut self) -> PResult<'a, Arg> {
         self.parse_arg_general(true, false)
     }
 
-    /// Parse an argument in a lambda header e.g., |arg, arg|
+    /// Parses an argument in a lambda header (e.g., `|arg, arg|`).
     fn parse_fn_block_arg(&mut self) -> PResult<'a, Arg> {
         let pat = self.parse_pat(Some("argument name"))?;
         let t = if self.eat(&token::Colon) {
@@ -1967,7 +2096,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Matches token_lit = LIT_INTEGER | ...
+    /// Matches `token_lit = LIT_INTEGER | ...`.
     fn parse_lit_token(&mut self) -> PResult<'a, LitKind> {
         let out = match self.token {
             token::Interpolated(ref nt) => match nt.0 {
@@ -1988,6 +2117,44 @@ impl<'a> Parser<'a> {
 
                 result.unwrap()
             }
+            token::Dot if self.look_ahead(1, |t| match t {
+                token::Literal(parse::token::Lit::Integer(_) , _) => true,
+                _ => false,
+            }) => { // recover from `let x = .4;`
+                let lo = self.span;
+                self.bump();
+                if let token::Literal(
+                    parse::token::Lit::Integer(val),
+                    suffix,
+                ) = self.token {
+                    let suffix = suffix.and_then(|s| {
+                        let s = s.as_str().get();
+                        if ["f32", "f64"].contains(&s) {
+                            Some(s)
+                        } else {
+                            None
+                        }
+                    }).unwrap_or("");
+                    self.bump();
+                    let sp = lo.to(self.prev_span);
+                    let mut err = self.diagnostic()
+                        .struct_span_err(sp, "float literals must have an integer part");
+                    err.span_suggestion(
+                        sp,
+                        "must have an integer part",
+                        format!("0.{}{}", val, suffix),
+                        Applicability::MachineApplicable,
+                    );
+                    err.emit();
+                    return Ok(match suffix {
+                        "f32" => ast::LitKind::Float(val, ast::FloatTy::F32),
+                        "f64" => ast::LitKind::Float(val, ast::FloatTy::F64),
+                        _ => ast::LitKind::FloatUnsuffixed(val),
+                    });
+                } else {
+                    unreachable!();
+                };
+            }
             _ => { return self.unexpected_last(&self.token); }
         };
 
@@ -1995,7 +2162,7 @@ impl<'a> Parser<'a> {
         Ok(out)
     }
 
-    /// Matches lit = true | false | token_lit
+    /// Matches `lit = true | false | token_lit`.
     crate fn parse_lit(&mut self) -> PResult<'a, Lit> {
         let lo = self.span;
         let lit = if self.eat_keyword(keywords::True) {
@@ -2009,7 +2176,7 @@ impl<'a> Parser<'a> {
         Ok(source_map::Spanned { node: lit, span: lo.to(self.prev_span) })
     }
 
-    /// matches '-' lit | lit (cf. ast_validation::AstValidator::check_expr_within_pat)
+    /// Matches `'-' lit | lit` (cf. `ast_validation::AstValidator::check_expr_within_pat`).
     crate fn parse_literal_maybe_minus(&mut self) -> PResult<'a, P<Expr>> {
         maybe_whole_expr!(self);
 
@@ -2051,7 +2218,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parses qualified path.
+    /// Parses a qualified path.
     /// Assumes that the leading `<` has been parsed already.
     ///
     /// `qualified_path = <type [as trait_ref]>::path`
@@ -2079,7 +2246,11 @@ impl<'a> Parser<'a> {
             path_span = self.span.to(self.span);
         }
 
+        // See doc comment for `unmatched_angle_bracket_count`.
         self.expect(&token::Gt)?;
+        self.unmatched_angle_bracket_count -= 1;
+        debug!("parse_qpath: (decrement) count={:?}", self.unmatched_angle_bracket_count);
+
         self.expect(&token::ModSep)?;
 
         let qself = QSelf { ty, path_span, position: path.segments.len() };
@@ -2123,8 +2294,9 @@ impl<'a> Parser<'a> {
         Ok(ast::Path { segments, span: lo.to(self.prev_span) })
     }
 
-    /// Like `parse_path`, but also supports parsing `Word` meta items into paths for back-compat.
-    /// This is used when parsing derive macro paths in `#[derive]` attributes.
+    /// Like `parse_path`, but also supports parsing `Word` meta items into paths for
+    /// backwards-compatibility. This is used when parsing derive macro paths in `#[derive]`
+    /// attributes.
     pub fn parse_path_allowing_meta(&mut self, style: PathStyle) -> PResult<'a, ast::Path> {
         let meta_ident = match self.token {
             token::Interpolated(ref nt) => match nt.0 {
@@ -2149,7 +2321,27 @@ impl<'a> Parser<'a> {
                            enable_warning: bool)
                            -> PResult<'a, ()> {
         loop {
-            segments.push(self.parse_path_segment(style, enable_warning)?);
+            let segment = self.parse_path_segment(style, enable_warning)?;
+            if style == PathStyle::Expr {
+                // In order to check for trailing angle brackets, we must have finished
+                // recursing (`parse_path_segment` can indirectly call this function),
+                // that is, the next token must be the highlighted part of the below example:
+                //
+                // `Foo::<Bar as Baz<T>>::Qux`
+                //                      ^ here
+                //
+                // As opposed to the below highlight (if we had only finished the first
+                // recursion):
+                //
+                // `Foo::<Bar as Baz<T>>::Qux`
+                //                     ^ here
+                //
+                // `PathStyle::Expr` is only provided at the root invocation and never in
+                // `parse_path_segment` to recurse and therefore can be checked to maintain
+                // this invariant.
+                self.check_trailing_angle_brackets(&segment, token::ModSep);
+            }
+            segments.push(segment);
 
             if self.is_import_coupler() || !self.eat(&token::ModSep) {
                 return Ok(());
@@ -2176,34 +2368,45 @@ impl<'a> Parser<'a> {
               style != PathStyle::Mod && self.check(&token::ModSep)
                                       && self.look_ahead(1, |t| is_args_start(t)) {
             // Generic arguments are found - `<`, `(`, `::<` or `::(`.
-            let lo = self.span;
             if self.eat(&token::ModSep) && style == PathStyle::Type && enable_warning {
                 self.diagnostic().struct_span_warn(self.prev_span, "unnecessary path disambiguator")
                                  .span_label(self.prev_span, "try removing `::`").emit();
             }
+            let lo = self.span;
+
+            // We use `style == PathStyle::Expr` to check if this is in a recursion or not. If
+            // it isn't, then we reset the unmatched angle bracket count as we're about to start
+            // parsing a new path.
+            if style == PathStyle::Expr {
+                self.unmatched_angle_bracket_count = 0;
+                self.max_angle_bracket_count = 0;
+            }
 
             let args = if self.eat_lt() {
                 // `<'a, T, A = U>`
-                let (args, bindings) = self.parse_generic_args()?;
+                let (args, bindings) =
+                    self.parse_generic_args_with_leaning_angle_bracket_recovery(style, lo)?;
                 self.expect_gt()?;
                 let span = lo.to(self.prev_span);
                 AngleBracketedArgs { args, bindings, span }.into()
             } else {
                 // `(T, U) -> R`
                 self.bump(); // `(`
-                let inputs = self.parse_seq_to_before_tokens(
+                let (inputs, recovered) = self.parse_seq_to_before_tokens(
                     &[&token::CloseDelim(token::Paren)],
                     SeqSep::trailing_allowed(token::Comma),
                     TokenExpectType::Expect,
                     |p| p.parse_ty())?;
-                self.bump(); // `)`
+                if !recovered {
+                    self.bump(); // `)`
+                }
                 let span = lo.to(self.prev_span);
                 let output = if self.eat(&token::RArrow) {
                     Some(self.parse_ty_common(false, false)?)
                 } else {
                     None
                 };
-                ParenthesisedArgs { inputs, output, span }.into()
+                ParenthesizedArgs { inputs, output, span }.into()
             };
 
             PathSegment { ident, args, id: ast::DUMMY_NODE_ID }
@@ -2218,7 +2421,7 @@ impl<'a> Parser<'a> {
         self.token.is_lifetime()
     }
 
-    /// Parse single lifetime 'a or panic.
+    /// Parses a single lifetime `'a` or panics.
     crate fn expect_lifetime(&mut self) -> Lifetime {
         if let Some(ident) = self.token.lifetime() {
             let span = self.span;
@@ -2239,7 +2442,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse mutability (`mut` or nothing).
+    /// Parses mutability (`mut` or nothing).
     fn parse_mutability(&mut self) -> Mutability {
         if self.eat_keyword(keywords::Mut) {
             Mutability::Mutable
@@ -2263,8 +2466,24 @@ impl<'a> Parser<'a> {
         let lo = self.span;
 
         // Check if a colon exists one ahead. This means we're parsing a fieldname.
-        let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| t == &token::Colon) {
+        let (fieldname, expr, is_shorthand) = if self.look_ahead(1, |t| {
+            t == &token::Colon || t == &token::Eq
+        }) {
             let fieldname = self.parse_field_name()?;
+
+            // Check for an equals token. This means the source incorrectly attempts to
+            // initialize a field with an eq rather than a colon.
+            if self.token == token::Eq {
+                self.diagnostic()
+                    .struct_span_err(self.span, "expected `:`, found `=`")
+                    .span_suggestion(
+                        fieldname.span.shrink_to_hi().to(self.span),
+                        "replace equals symbol with a colon",
+                        ":".to_string(),
+                        Applicability::MachineApplicable,
+                    )
+                    .emit();
+            }
             self.bump(); // `:`
             (fieldname, self.parse_expr()?, false)
         } else {
@@ -2330,7 +2549,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, ThinTokenStream)> {
+    fn expect_delimited_token_tree(&mut self) -> PResult<'a, (MacDelimiter, TokenStream)> {
         let delim = match self.token {
             token::OpenDelim(delim) => delim,
             _ => {
@@ -2350,16 +2569,14 @@ impl<'a> Parser<'a> {
             token::Brace => MacDelimiter::Brace,
             token::NoDelim => self.bug("unexpected no delimiter"),
         };
-        Ok((delim, tts.stream().into()))
+        Ok((delim, tts.into()))
     }
 
     /// At the bottom (top?) of the precedence hierarchy,
-    /// parse things like parenthesized exprs,
-    /// macros, return, etc.
+    /// Parses things like parenthesized exprs, macros, `return`, etc.
     ///
-    /// N.B., this does not parse outer attributes,
-    ///     and is private because it only works
-    ///     correctly if called from parse_dot_or_call_expr().
+    /// N.B., this does not parse outer attributes, and is private because it only works
+    /// correctly if called from `parse_dot_or_call_expr()`.
     fn parse_bottom_expr(&mut self) -> PResult<'a, P<Expr>> {
         maybe_whole_expr!(self);
 
@@ -2386,9 +2603,13 @@ impl<'a> Parser<'a> {
                 // (e,) is a tuple with only one field, e
                 let mut es = vec![];
                 let mut trailing_comma = false;
+                let mut recovered = false;
                 while self.token != token::CloseDelim(token::Paren) {
                     es.push(self.parse_expr()?);
-                    self.expect_one_of(&[], &[token::Comma, token::CloseDelim(token::Paren)])?;
+                    recovered = self.expect_one_of(
+                        &[],
+                        &[token::Comma, token::CloseDelim(token::Paren)],
+                    )?;
                     if self.eat(&token::Comma) {
                         trailing_comma = true;
                     } else {
@@ -2396,7 +2617,9 @@ impl<'a> Parser<'a> {
                         break;
                     }
                 }
-                self.bump();
+                if !recovered {
+                    self.bump();
+                }
 
                 hi = self.prev_span;
                 ex = if es.len() == 1 && !trailing_comma {
@@ -2593,6 +2816,21 @@ impl<'a> Parser<'a> {
                     hi = pth.span;
                     ex = ExprKind::Path(None, pth);
                 } else {
+                    if !self.unclosed_delims.is_empty() && self.check(&token::Semi) {
+                        // Don't complain about bare semicolons after unclosed braces
+                        // recovery in order to keep the error count down. Fixing the
+                        // delimiters will possibly also fix the bare semicolon found in
+                        // expression context. For example, silence the following error:
+                        // ```
+                        // error: expected expression, found `;`
+                        //  --> file.rs:2:13
+                        //   |
+                        // 2 |     foo(bar(;
+                        //   |             ^ expected expression
+                        // ```
+                        self.bump();
+                        return Ok(self.mk_expr(self.span, ExprKind::Err, ThinVec::new()));
+                    }
                     match self.parse_literal_maybe_minus() {
                         Ok(expr) => {
                             hi = expr.span;
@@ -2643,7 +2881,7 @@ impl<'a> Parser<'a> {
                         exp_span.to(self.prev_span),
                         "cannot use a comma after the base struct",
                     );
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         self.span,
                         "remove this comma",
                         String::new(),
@@ -2656,8 +2894,24 @@ impl<'a> Parser<'a> {
                 break;
             }
 
+            let mut recovery_field = None;
+            if let token::Ident(ident, _) = self.token {
+                if !self.token.is_reserved_ident() && self.look_ahead(1, |t| *t == token::Colon) {
+                    // Use in case of error after field-looking code: `S { foo: () with a }`
+                    let mut ident = ident.clone();
+                    ident.span = self.span;
+                    recovery_field = Some(ast::Field {
+                        ident,
+                        span: self.span,
+                        expr: self.mk_expr(self.span, ExprKind::Err, ThinVec::new()),
+                        is_shorthand: false,
+                        attrs: ThinVec::new(),
+                    });
+                }
+            }
+            let mut parsed_field = None;
             match self.parse_field() {
-                Ok(f) => fields.push(f),
+                Ok(f) => parsed_field = Some(f),
                 Err(mut e) => {
                     e.span_label(struct_sp, "while parsing this struct");
                     e.emit();
@@ -2666,19 +2920,28 @@ impl<'a> Parser<'a> {
                     // what comes next as additional fields, rather than
                     // bailing out until next `}`.
                     if self.token != token::Comma {
-                        self.recover_stmt();
-                        break;
+                        self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
+                        if self.token != token::Comma {
+                            break;
+                        }
                     }
                 }
             }
 
             match self.expect_one_of(&[token::Comma],
                                      &[token::CloseDelim(token::Brace)]) {
-                Ok(()) => {}
+                Ok(_) => if let Some(f) = parsed_field.or(recovery_field) {
+                    // only include the field if there's no parse error for the field name
+                    fields.push(f);
+                }
                 Err(mut e) => {
+                    if let Some(f) = recovery_field {
+                        fields.push(f);
+                    }
+                    e.span_label(struct_sp, "while parsing this struct");
                     e.emit();
-                    self.recover_stmt();
-                    break;
+                    self.recover_stmt_(SemiColonMode::Comma, BlockMode::Ignore);
+                    self.eat(&token::Comma);
                 }
             }
         }
@@ -2698,7 +2961,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse a block or unsafe block
+    /// Parses a block or unsafe block.
     fn parse_block_expr(&mut self, opt_label: Option<Label>,
                             lo: Span, blk_mode: BlockCheckMode,
                             outer_attrs: ThinVec<Attribute>)
@@ -2712,7 +2975,7 @@ impl<'a> Parser<'a> {
         return Ok(self.mk_expr(blk.span, ExprKind::Block(blk, opt_label), attrs));
     }
 
-    /// parse a.b or a(13) or a[4] or just a
+    /// Parses `a.b` or `a(13)` or `a[4]` or just `a`.
     fn parse_dot_or_call_expr(&mut self,
                                   already_parsed_attrs: Option<ThinVec<Attribute>>)
                                   -> PResult<'a, P<Expr>> {
@@ -2757,6 +3020,8 @@ impl<'a> Parser<'a> {
     // Assuming we have just parsed `.`, continue parsing into an expression.
     fn parse_dot_suffix(&mut self, self_arg: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
         let segment = self.parse_path_segment(PathStyle::Expr, true)?;
+        self.check_trailing_angle_brackets(&segment, token::OpenDelim(token::Paren));
+
         Ok(match self.token {
             token::OpenDelim(token::Paren) => {
                 // Method call `expr.f()`
@@ -2784,6 +3049,116 @@ impl<'a> Parser<'a> {
         })
     }
 
+    /// This function checks if there are trailing angle brackets and produces
+    /// a diagnostic to suggest removing them.
+    ///
+    /// ```ignore (diagnostic)
+    /// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+    ///                                                        ^^ help: remove extra angle brackets
+    /// ```
+    fn check_trailing_angle_brackets(&mut self, segment: &PathSegment, end: token::Token) {
+        // This function is intended to be invoked after parsing a path segment where there are two
+        // cases:
+        //
+        // 1. A specific token is expected after the path segment.
+        //    eg. `x.foo(`, `x.foo::<u32>(` (parenthesis - method call),
+        //        `Foo::`, or `Foo::<Bar>::` (mod sep - continued path).
+        // 2. No specific token is expected after the path segment.
+        //    eg. `x.foo` (field access)
+        //
+        // This function is called after parsing `.foo` and before parsing the token `end` (if
+        // present). This includes any angle bracket arguments, such as `.foo::<u32>` or
+        // `Foo::<Bar>`.
+
+        // We only care about trailing angle brackets if we previously parsed angle bracket
+        // arguments. This helps stop us incorrectly suggesting that extra angle brackets be
+        // removed in this case:
+        //
+        // `x.foo >> (3)` (where `x.foo` is a `u32` for example)
+        //
+        // This case is particularly tricky as we won't notice it just looking at the tokens -
+        // it will appear the same (in terms of upcoming tokens) as below (since the `::<u32>` will
+        // have already been parsed):
+        //
+        // `x.foo::<u32>>>(3)`
+        let parsed_angle_bracket_args = segment.args
+            .as_ref()
+            .map(|args| args.is_angle_bracketed())
+            .unwrap_or(false);
+
+        debug!(
+            "check_trailing_angle_brackets: parsed_angle_bracket_args={:?}",
+            parsed_angle_bracket_args,
+        );
+        if !parsed_angle_bracket_args {
+            return;
+        }
+
+        // Keep the span at the start so we can highlight the sequence of `>` characters to be
+        // removed.
+        let lo = self.span;
+
+        // We need to look-ahead to see if we have `>` characters without moving the cursor forward
+        // (since we might have the field access case and the characters we're eating are
+        // actual operators and not trailing characters - ie `x.foo >> 3`).
+        let mut position = 0;
+
+        // We can encounter `>` or `>>` tokens in any order, so we need to keep track of how
+        // many of each (so we can correctly pluralize our error messages) and continue to
+        // advance.
+        let mut number_of_shr = 0;
+        let mut number_of_gt = 0;
+        while self.look_ahead(position, |t| {
+            trace!("check_trailing_angle_brackets: t={:?}", t);
+            if *t == token::BinOp(token::BinOpToken::Shr) {
+                number_of_shr += 1;
+                true
+            } else if *t == token::Gt {
+                number_of_gt += 1;
+                true
+            } else {
+                false
+            }
+        }) {
+            position += 1;
+        }
+
+        // If we didn't find any trailing `>` characters, then we have nothing to error about.
+        debug!(
+            "check_trailing_angle_brackets: number_of_gt={:?} number_of_shr={:?}",
+            number_of_gt, number_of_shr,
+        );
+        if number_of_gt < 1 && number_of_shr < 1 {
+            return;
+        }
+
+        // Finally, double check that we have our end token as otherwise this is the
+        // second case.
+        if self.look_ahead(position, |t| {
+            trace!("check_trailing_angle_brackets: t={:?}", t);
+            *t == end
+        }) {
+            // Eat from where we started until the end token so that parsing can continue
+            // as if we didn't have those extra angle brackets.
+            self.eat_to_tokens(&[&end]);
+            let span = lo.until(self.span);
+
+            let plural = number_of_gt > 1 || number_of_shr >= 1;
+            self.diagnostic()
+                .struct_span_err(
+                    span,
+                    &format!("unmatched angle bracket{}", if plural { "s" } else { "" }),
+                )
+                .span_suggestion(
+                    span,
+                    &format!("remove extra angle bracket{}", if plural { "s" } else { "" }),
+                    String::new(),
+                    Applicability::MachineApplicable,
+                )
+                .emit();
+        }
+    }
+
     fn parse_dot_or_call_expr_with_(&mut self, e0: P<Expr>, lo: Span) -> PResult<'a, P<Expr>> {
         let mut e = e0;
         let mut hi;
@@ -2818,7 +3193,7 @@ impl<'a> Parser<'a> {
                             None => continue,
                         };
                         let sugg = pprust::to_string(|s| {
-                            use print::pprust::PrintState;
+                            use crate::print::pprust::PrintState;
                             s.popen()?;
                             s.print_expr(&e)?;
                             s.s.word( ".")?;
@@ -2827,7 +3202,7 @@ impl<'a> Parser<'a> {
                             s.s.word(".")?;
                             s.s.word(fstr.splitn(2, ".").last().unwrap().to_string())
                         });
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             lo.to(self.prev_span),
                             "try parenthesizing the first index",
                             sugg,
@@ -2908,7 +3283,7 @@ impl<'a> Parser<'a> {
         self.span = span;
     }
 
-    /// parse a single token tree from the input.
+    /// Parses a single token tree from the input.
     crate fn parse_token_tree(&mut self) -> TokenTree {
         match self.token {
             token::OpenDelim(..) => {
@@ -2974,7 +3349,7 @@ impl<'a> Parser<'a> {
                 let span_of_tilde = lo;
                 let mut err = self.diagnostic()
                     .struct_span_err(span_of_tilde, "`~` cannot be used as a unary operator");
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     span_of_tilde,
                     "use `!` to perform bitwise negation",
                     "!".to_owned(),
@@ -3047,7 +3422,7 @@ impl<'a> Parser<'a> {
                     // trailing whitespace after the `!` in our suggestion
                     let to_replace = self.sess.source_map()
                         .span_until_non_whitespace(lo.to(self.span));
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         to_replace,
                         "use `!` to perform logical negation",
                         "!".to_owned(),
@@ -3068,7 +3443,7 @@ impl<'a> Parser<'a> {
         return Ok(self.mk_expr(lo.to(hi), ex, attrs));
     }
 
-    /// Parse an associative expression
+    /// Parses an associative expression.
     ///
     /// This parses an expression accounting for associativity and precedence of the operators in
     /// the expression.
@@ -3079,7 +3454,7 @@ impl<'a> Parser<'a> {
         self.parse_assoc_expr_with(0, already_parsed_attrs.into())
     }
 
-    /// Parse an associative expression with operators of at least `min_prec` precedence
+    /// Parses an associative expression with operators of at least `min_prec` precedence.
     fn parse_assoc_expr_with(&mut self,
                                  min_prec: usize,
                                  lhs: LhsExpr)
@@ -3148,7 +3523,7 @@ impl<'a> Parser<'a> {
                         let cur_pos = cm.lookup_char_pos(self.span.lo());
                         let op_pos = cm.lookup_char_pos(cur_op_span.hi());
                         if cur_pos.line != op_pos.line {
-                            err.span_suggestion_with_applicability(
+                            err.span_suggestion(
                                 cur_op_span,
                                 "try using a semicolon",
                                 ";".to_string(),
@@ -3210,6 +3585,14 @@ impl<'a> Parser<'a> {
                 }),
             }?;
 
+            // Make sure that the span of the parent node is larger than the span of lhs and rhs,
+            // including the attributes.
+            let lhs_span = lhs
+                .attrs
+                .iter()
+                .filter(|a| a.style == AttrStyle::Outer)
+                .next()
+                .map_or(lhs_span, |a| a.span);
             let span = lhs_span.to(rhs.span);
             lhs = match op {
                 AssocOp::Add | AssocOp::Subtract | AssocOp::Multiply | AssocOp::Divide |
@@ -3307,7 +3690,7 @@ impl<'a> Parser<'a> {
 
                         let expr_str = self.sess.source_map().span_to_snippet(expr.span)
                                                 .unwrap_or_else(|_| pprust::expr_to_string(&expr));
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             expr.span,
                             &format!("try {} the cast value", op_verb),
                             format!("({})", expr_str),
@@ -3406,7 +3789,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse an 'if' or 'if let' expression ('if' token already eaten)
+    /// Parses an `if` or `if let` expression (`if` token already eaten).
     fn parse_if_expr(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
         if self.check_keyword(keywords::Let) {
             return self.parse_if_let_expr(attrs);
@@ -3442,7 +3825,7 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(lo.to(hi), ExprKind::If(cond, thn, els), attrs))
     }
 
-    /// Parse an 'if let' expression ('if' token already eaten)
+    /// Parses an `if let` expression (`if` token already eaten).
     fn parse_if_let_expr(&mut self, attrs: ThinVec<Attribute>)
                              -> PResult<'a, P<Expr>> {
         let lo = self.prev_span;
@@ -3460,7 +3843,7 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(lo.to(hi), ExprKind::IfLet(pats, expr, thn, els), attrs))
     }
 
-    // `move |args| expr`
+    /// Parses `move |args| expr`.
     fn parse_lambda_expr(&mut self,
                              attrs: ThinVec<Attribute>)
                              -> PResult<'a, P<Expr>>
@@ -3523,7 +3906,7 @@ impl<'a> Parser<'a> {
             let in_span = self.prev_span.between(self.span);
             let mut err = self.sess.span_diagnostic
                 .struct_span_err(in_span, "missing `in` in `for` loop");
-            err.span_suggestion_short_with_applicability(
+            err.span_suggestion_short(
                 in_span, "try adding `in` here", " in ".into(),
                 // has been misleading, at least in the past (closed Issue #48492)
                 Applicability::MaybeIncorrect
@@ -3537,7 +3920,7 @@ impl<'a> Parser<'a> {
                 self.prev_span,
                 "expected iterable, found keyword `in`",
             );
-            err.span_suggestion_short_with_applicability(
+            err.span_suggestion_short(
                 in_span.until(self.prev_span),
                 "remove the duplicated `in`",
                 String::new(),
@@ -3556,7 +3939,7 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(span_lo.to(hi), ExprKind::ForLoop(pat, expr, loop_block, opt_label), attrs))
     }
 
-    /// Parse a 'while' or 'while let' expression ('while' token already eaten)
+    /// Parses a `while` or `while let` expression (`while` token already eaten).
     fn parse_while_expr(&mut self, opt_label: Option<Label>,
                             span_lo: Span,
                             mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
@@ -3570,7 +3953,7 @@ impl<'a> Parser<'a> {
         return Ok(self.mk_expr(span, ExprKind::While(cond, body, opt_label), attrs));
     }
 
-    /// Parse a 'while let' expression ('while' token already eaten)
+    /// Parses a `while let` expression (`while` token already eaten).
     fn parse_while_let_expr(&mut self, opt_label: Option<Label>,
                                 span_lo: Span,
                                 mut attrs: ThinVec<Attribute>) -> PResult<'a, P<Expr>> {
@@ -3594,7 +3977,7 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(span, ExprKind::Loop(body, opt_label), attrs))
     }
 
-    /// Parse an `async move {...}` expression
+    /// Parses an `async move {...}` expression.
     pub fn parse_async_block(&mut self, mut attrs: ThinVec<Attribute>)
         -> PResult<'a, P<Expr>>
     {
@@ -3612,7 +3995,7 @@ impl<'a> Parser<'a> {
             ExprKind::Async(capture_clause, ast::DUMMY_NODE_ID, body), attrs))
     }
 
-    /// Parse a `try {...}` expression (`try` token already eaten)
+    /// Parses a `try {...}` expression (`try` token already eaten).
     fn parse_try_block(&mut self, span_lo: Span, mut attrs: ThinVec<Attribute>)
         -> PResult<'a, P<Expr>>
     {
@@ -3629,7 +4012,7 @@ impl<'a> Parser<'a> {
                                                None)?;
         if let Err(mut e) = self.expect(&token::OpenDelim(token::Brace)) {
             if self.token == token::Token::Semi {
-                e.span_suggestion_short_with_applicability(
+                e.span_suggestion_short(
                     match_span,
                     "try removing this `match`",
                     String::new(),
@@ -3704,7 +4087,7 @@ impl<'a> Parser<'a> {
                             //   |      - ^^ self.span
                             //   |      |
                             //   |      parsed until here as `"y" & X`
-                            err.span_suggestion_short_with_applicability(
+                            err.span_suggestion_short(
                                 cm.next_point(arm_start_span),
                                 "missing a comma here to end this `match` arm",
                                 ",".to_owned(),
@@ -3730,15 +4113,15 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse an expression
+    /// Parses an expression.
     #[inline]
     pub fn parse_expr(&mut self) -> PResult<'a, P<Expr>> {
         self.parse_expr_res(Restrictions::empty(), None)
     }
 
-    /// Evaluate the closure with restrictions in place.
+    /// Evaluates the closure with restrictions in place.
     ///
-    /// After the closure is evaluated, restrictions are reset.
+    /// Afters the closure is evaluated, restrictions are reset.
     fn with_res<F, T>(&mut self, r: Restrictions, f: F) -> T
         where F: FnOnce(&mut Self) -> T
     {
@@ -3750,7 +4133,7 @@ impl<'a> Parser<'a> {
 
     }
 
-    /// Parse an expression, subject to the given restrictions
+    /// Parses an expression, subject to the given restrictions.
     #[inline]
     fn parse_expr_res(&mut self, r: Restrictions,
                           already_parsed_attrs: Option<ThinVec<Attribute>>)
@@ -3758,7 +4141,7 @@ impl<'a> Parser<'a> {
         self.with_res(r, |this| this.parse_assoc_expr(already_parsed_attrs))
     }
 
-    /// Parse the RHS of a local variable declaration (e.g., '= 14;')
+    /// Parses the RHS of a local variable declaration (e.g., '= 14;').
     fn parse_initializer(&mut self, skip_eq: bool) -> PResult<'a, Option<P<Expr>>> {
         if self.eat(&token::Eq) {
             Ok(Some(self.parse_expr()?))
@@ -3769,7 +4152,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse patterns, separated by '|' s
+    /// Parses patterns, separated by '|' s.
     fn parse_pats(&mut self) -> PResult<'a, Vec<P<Pat>>> {
         // Allow a '|' before the pats (RFC 1925 + RFC 2530)
         self.eat(&token::BinOp(token::Or));
@@ -3781,7 +4164,7 @@ impl<'a> Parser<'a> {
             if self.token == token::OrOr {
                 let mut err = self.struct_span_err(self.span,
                                                    "unexpected token `||` after pattern");
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     self.span,
                     "use a single `|` to specify multiple patterns",
                     "|".to_owned(),
@@ -3790,7 +4173,8 @@ impl<'a> Parser<'a> {
                 err.emit();
                 self.bump();
             } else if self.eat(&token::BinOp(token::Or)) {
-                // No op.
+                // This is a No-op. Continue the loop to parse the next
+                // pattern.
             } else {
                 return Ok(pats);
             }
@@ -3959,7 +4343,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse the fields of a struct-like pattern
+    /// Parses the fields of a struct-like pattern.
     fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<source_map::Spanned<ast::FieldPat>>, bool)> {
         let mut fields = Vec::new();
         let mut etc = false;
@@ -3989,7 +4373,7 @@ impl<'a> Parser<'a> {
                     // Accept `...` as if it were `..` to avoid further errors
                     let mut err = self.struct_span_err(self.span,
                                                        "expected field pattern, found `...`");
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         self.span,
                         "to omit remaining fields, use one fewer `.`",
                         "..".to_owned(),
@@ -4021,7 +4405,7 @@ impl<'a> Parser<'a> {
                 if self.token == token::CloseDelim(token::Brace) {
                     // If the struct looks otherwise well formed, recover and continue.
                     if let Some(sp) = comma_sp {
-                        err.span_suggestion_short_with_applicability(
+                        err.span_suggestion_short(
                             sp,
                             "remove this comma",
                             String::new(),
@@ -4069,6 +4453,7 @@ impl<'a> Parser<'a> {
                         (etc_span, String::new()),
                         (self.span, format!("{}.. }}", if ate_comma { "" } else { ", " })),
                     ],
+                    Applicability::MachineApplicable,
                 );
             }
             err.emit();
@@ -4133,11 +4518,16 @@ impl<'a> Parser<'a> {
             let mut err = self.struct_span_err(comma_span,
                                                "unexpected `,` in pattern");
             if let Ok(seq_snippet) = self.sess.source_map().span_to_snippet(seq_span) {
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     seq_span,
-                    "try adding parentheses",
+                    "try adding parentheses to match on a tuple..",
                     format!("({})", seq_snippet),
                     Applicability::MachineApplicable
+                ).span_suggestion(
+                    seq_span,
+                    "..or a vertical bar to match on multiple alternatives",
+                    format!("{}", seq_snippet.replace(",", " |")),
+                    Applicability::MachineApplicable
                 );
             }
             return Err(err);
@@ -4145,13 +4535,13 @@ impl<'a> Parser<'a> {
         Ok(pat)
     }
 
-    /// Parse a pattern.
+    /// Parses a pattern.
     pub fn parse_pat(&mut self, expected: Option<&'static str>) -> PResult<'a, P<Pat>> {
         self.parse_pat_with_range_pat(true, expected)
     }
 
-    /// Parse a pattern, with a setting whether modern range patterns e.g., `a..=b`, `a..b` are
-    /// allowed.
+    /// Parses a pattern, with a setting whether modern range patterns (e.g., `a..=b`, `a..b` are
+    /// allowed).
     fn parse_pat_with_range_pat(
         &mut self,
         allow_range_pat: bool,
@@ -4201,7 +4591,7 @@ impl<'a> Parser<'a> {
                 let binding_mode = if self.eat_keyword(keywords::Ref) {
                     self.diagnostic()
                         .struct_span_err(mutref_span, "the order of `mut` and `ref` is incorrect")
-                        .span_suggestion_with_applicability(
+                        .span_suggestion(
                             mutref_span,
                             "try switching the order",
                             "ref mut".into(),
@@ -4345,7 +4735,7 @@ impl<'a> Parser<'a> {
                         pat.span,
                         "the range pattern here has ambiguous interpretation",
                     );
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         pat.span,
                         "add parentheses to clarify the precedence",
                         format!("({})", pprust::pat_to_string(&pat)),
@@ -4361,9 +4751,9 @@ impl<'a> Parser<'a> {
         Ok(P(pat))
     }
 
-    /// Parse ident or ident @ pat
+    /// Parses `ident` or `ident @ pat`.
     /// used by the copy foo and ref foo patterns to give a good
-    /// error message when parsing mistakes like ref foo(a,b)
+    /// error message when parsing mistakes like `ref foo(a, b)`.
     fn parse_pat_ident(&mut self,
                        binding_mode: ast::BindingMode)
                        -> PResult<'a, PatKind> {
@@ -4389,7 +4779,7 @@ impl<'a> Parser<'a> {
         Ok(PatKind::Ident(binding_mode, ident, sub))
     }
 
-    /// Parse a local variable declaration
+    /// Parses a local variable declaration.
     fn parse_local(&mut self, attrs: ThinVec<Attribute>) -> PResult<'a, P<Local>> {
         let lo = self.prev_span;
         let pat = self.parse_top_level_pat()?;
@@ -4421,7 +4811,7 @@ impl<'a> Parser<'a> {
             (Ok(init), Some((_, colon_sp, mut err))) => {  // init parsed, ty error
                 // Could parse the type as if it were the initializer, it is likely there was a
                 // typo in the code: `:` instead of `=`. Add suggestion and emit the error.
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     colon_sp,
                     "use `=` if you meant to assign",
                     "=".to_string(),
@@ -4462,7 +4852,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Parse a structure field
+    /// Parses a structure field.
     fn parse_name_and_ty(&mut self,
                          lo: Span,
                          vis: Visibility,
@@ -4481,14 +4871,18 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Emit an expected item after attributes error.
-    fn expected_item_err(&self, attrs: &[Attribute]) {
+    /// Emits an expected-item-after-attributes error.
+    fn expected_item_err(&mut self, attrs: &[Attribute]) -> PResult<'a,  ()> {
         let message = match attrs.last() {
             Some(&Attribute { is_sugared_doc: true, .. }) => "expected item after doc comment",
             _ => "expected item after attributes",
         };
 
-        self.span_err(self.prev_span, message);
+        let mut err = self.diagnostic().struct_span_err(self.prev_span, message);
+        if attrs.last().unwrap().is_sugared_doc {
+            err.span_label(self.prev_span, "this doc comment doesn't document anything");
+        }
+        Err(err)
     }
 
     /// Parse a statement. This stops just before trailing semicolons on everything but items.
@@ -4537,13 +4931,13 @@ impl<'a> Parser<'a> {
                 token::CloseDelim(token::DelimToken::Brace) => {
                     if brace_depth == 0 {
                         debug!("recover_stmt_ return - close delim {:?}", self.token);
-                        return;
+                        break;
                     }
                     brace_depth -= 1;
                     self.bump();
                     if in_block && bracket_depth == 0 && brace_depth == 0 {
                         debug!("recover_stmt_ return - block end {:?}", self.token);
-                        return;
+                        break;
                     }
                 }
                 token::CloseDelim(token::DelimToken::Bracket) => {
@@ -4555,7 +4949,7 @@ impl<'a> Parser<'a> {
                 }
                 token::Eof => {
                     debug!("recover_stmt_ return - Eof");
-                    return;
+                    break;
                 }
                 token::Semi => {
                     self.bump();
@@ -4563,7 +4957,17 @@ impl<'a> Parser<'a> {
                        brace_depth == 0 &&
                        bracket_depth == 0 {
                         debug!("recover_stmt_ return - Semi");
-                        return;
+                        break;
+                    }
+                }
+                token::Comma => {
+                    if break_on_semi == SemiColonMode::Comma &&
+                       brace_depth == 0 &&
+                       bracket_depth == 0 {
+                        debug!("recover_stmt_ return - Semi");
+                        break;
+                    } else {
+                        self.bump();
                     }
                 }
                 _ => {
@@ -4641,7 +5045,7 @@ impl<'a> Parser<'a> {
                 let ident = self.parse_ident()?;
                 let tokens = if self.check(&token::OpenDelim(token::Brace)) {
                     match self.parse_token_tree() {
-                        TokenTree::Delimited(_, _, tts) => tts.stream(),
+                        TokenTree::Delimited(_, _, tts) => tts,
                         _ => unreachable!(),
                     }
                 } else if self.check(&token::OpenDelim(token::Paren)) {
@@ -4890,13 +5294,13 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Is this expression a successfully-parsed statement?
+    /// Checks if this expression is a successfully parsed statement.
     fn expr_is_complete(&mut self, e: &Expr) -> bool {
         self.restrictions.contains(Restrictions::STMT_EXPR) &&
             !classify::expr_requires_semi_to_be_stmt(e)
     }
 
-    /// Parse a block. No inner attrs are allowed.
+    /// Parses a block. No inner attributes are allowed.
     pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
         maybe_whole!(self, NtBlock, |x| x);
 
@@ -4910,7 +5314,7 @@ impl<'a> Parser<'a> {
                 self.token.is_keyword(keywords::In) || self.token == token::Colon;
 
             if self.token.is_ident_named("and") {
-                e.span_suggestion_short_with_applicability(
+                e.span_suggestion_short(
                     self.span,
                     "use `&&` instead of `and` for the boolean operator",
                     "&&".to_string(),
@@ -4918,7 +5322,7 @@ impl<'a> Parser<'a> {
                 );
             }
             if self.token.is_ident_named("or") {
-                e.span_suggestion_short_with_applicability(
+                e.span_suggestion_short(
                     self.span,
                     "use `||` instead of `or` for the boolean operator",
                     "||".to_string(),
@@ -4947,13 +5351,13 @@ impl<'a> Parser<'a> {
                         stmt_span = stmt_span.with_hi(self.prev_span.hi());
                     }
                     let sugg = pprust::to_string(|s| {
-                        use print::pprust::{PrintState, INDENT_UNIT};
+                        use crate::print::pprust::{PrintState, INDENT_UNIT};
                         s.ibox(INDENT_UNIT)?;
                         s.bopen()?;
                         s.print_stmt(&stmt)?;
                         s.bclose_maybe_open(stmt.span, INDENT_UNIT, false)
                     });
-                    e.span_suggestion_with_applicability(
+                    e.span_suggestion(
                         stmt_span,
                         "try placing this code inside a block",
                         sugg,
@@ -4974,7 +5378,7 @@ impl<'a> Parser<'a> {
         self.parse_block_tail(lo, BlockCheckMode::Default)
     }
 
-    /// Parse a block. Inner attrs are allowed.
+    /// Parses a block. Inner attributes are allowed.
     fn parse_inner_attrs_and_block(&mut self) -> PResult<'a, (Vec<Attribute>, P<Block>)> {
         maybe_whole!(self, NtBlock, |x| (Vec::new(), x));
 
@@ -4984,7 +5388,7 @@ impl<'a> Parser<'a> {
             self.parse_block_tail(lo, BlockCheckMode::Default)?))
     }
 
-    /// Parse the rest of a block expression or function body
+    /// Parses the rest of a block expression or function body.
     /// Precondition: already parsed the '{'.
     fn parse_block_tail(&mut self, lo: Span, s: BlockCheckMode) -> PResult<'a, P<Block>> {
         let mut stmts = vec![];
@@ -5018,7 +5422,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Parse a statement, including the trailing semicolon.
+    /// Parses a statement, including the trailing semicolon.
     crate fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
         // skip looking for a trailing semicolon when we have an interpolated statement
         maybe_whole!(self, NtStmt, |x| Some(x));
@@ -5071,20 +5475,23 @@ impl<'a> Parser<'a> {
     fn err_dotdotdot_syntax(&self, span: Span) {
         self.diagnostic().struct_span_err(span, {
             "unexpected token: `...`"
-        }).span_suggestion_with_applicability(
+        }).span_suggestion(
             span, "use `..` for an exclusive range", "..".to_owned(),
             Applicability::MaybeIncorrect
-        ).span_suggestion_with_applicability(
+        ).span_suggestion(
             span, "or `..=` for an inclusive range", "..=".to_owned(),
             Applicability::MaybeIncorrect
         ).emit();
     }
 
-    // Parse bounds of a type parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
-    // BOUND = TY_BOUND | LT_BOUND
-    // LT_BOUND = LIFETIME (e.g., `'a`)
-    // TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
-    // TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g., `?for<'a: 'b> m::Trait<'a>`)
+    /// Parses bounds of a type parameter `BOUND + BOUND + ...`, possibly with trailing `+`.
+    ///
+    /// ```
+    /// BOUND = TY_BOUND | LT_BOUND
+    /// LT_BOUND = LIFETIME (e.g., `'a`)
+    /// TY_BOUND = TY_BOUND_NOPAREN | (TY_BOUND_NOPAREN)
+    /// TY_BOUND_NOPAREN = [?] [for<LT_PARAM_DEFS>] SIMPLE_PATH (e.g., `?for<'a: 'b> m::Trait<'a>`)
+    /// ```
     fn parse_generic_bounds_common(&mut self, allow_plus: bool) -> PResult<'a, GenericBounds> {
         let mut bounds = Vec::new();
         loop {
@@ -5096,6 +5503,7 @@ impl<'a> Parser<'a> {
             if is_bound_start {
                 let lo = self.span;
                 let has_parens = self.eat(&token::OpenDelim(token::Paren));
+                let inner_lo = self.span;
                 let question = if self.eat(&token::Question) { Some(self.prev_span) } else { None };
                 if self.token.is_lifetime() {
                     if let Some(question_span) = question {
@@ -5104,9 +5512,21 @@ impl<'a> Parser<'a> {
                     }
                     bounds.push(GenericBound::Outlives(self.expect_lifetime()));
                     if has_parens {
+                        let inner_span = inner_lo.to(self.prev_span);
                         self.expect(&token::CloseDelim(token::Paren))?;
-                        self.span_err(self.prev_span,
-                                      "parenthesized lifetime bounds are not supported");
+                        let mut err = self.struct_span_err(
+                            lo.to(self.prev_span),
+                            "parenthesized lifetime bounds are not supported"
+                        );
+                        if let Ok(snippet) = self.sess.source_map().span_to_snippet(inner_span) {
+                            err.span_suggestion_short(
+                                lo.to(self.prev_span),
+                                "remove the parentheses",
+                                snippet.to_owned(),
+                                Applicability::MachineApplicable
+                            );
+                        }
+                        err.emit();
                     }
                 } else {
                     let lifetime_defs = self.parse_late_bound_lifetime_defs()?;
@@ -5138,8 +5558,11 @@ impl<'a> Parser<'a> {
         self.parse_generic_bounds_common(true)
     }
 
-    // Parse bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
-    // BOUND = LT_BOUND (e.g., `'a`)
+    /// Parses bounds of a lifetime parameter `BOUND + BOUND + BOUND`, possibly with trailing `+`.
+    ///
+    /// ```
+    /// BOUND = LT_BOUND (e.g., `'a`)
+    /// ```
     fn parse_lt_param_bounds(&mut self) -> GenericBounds {
         let mut lifetimes = Vec::new();
         while self.check_lifetime() {
@@ -5152,7 +5575,7 @@ impl<'a> Parser<'a> {
         lifetimes
     }
 
-    /// Matches typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?
+    /// Matches `typaram = IDENT (`?` unbound)? optbounds ( EQ ty )?`.
     fn parse_ty_param(&mut self,
                       preceding_attrs: Vec<Attribute>)
                       -> PResult<'a, GenericParam> {
@@ -5183,6 +5606,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses the following grammar:
+    ///
     ///     TraitItemAssocTy = Ident ["<"...">"] [":" [GenericBounds]] ["where" ...] ["=" Ty]
     fn parse_trait_item_assoc_ty(&mut self)
         -> PResult<'a, (Ident, TraitItemKind, ast::Generics)> {
@@ -5207,15 +5631,27 @@ impl<'a> Parser<'a> {
         Ok((ident, TraitItemKind::Type(bounds, default), generics))
     }
 
-    /// Parses (possibly empty) list of lifetime and type parameters, possibly including
-    /// trailing comma and erroneous trailing attributes.
+    fn parse_const_param(&mut self, preceding_attrs: Vec<Attribute>) -> PResult<'a, GenericParam> {
+        self.expect_keyword(keywords::Const)?;
+        let ident = self.parse_ident()?;
+        self.expect(&token::Colon)?;
+        let ty = self.parse_ty()?;
+
+        Ok(GenericParam {
+            ident,
+            id: ast::DUMMY_NODE_ID,
+            attrs: preceding_attrs.into(),
+            bounds: Vec::new(),
+            kind: GenericParamKind::Const {
+                ty,
+            }
+        })
+    }
+
+    /// Parses a (possibly empty) list of lifetime and type parameters, possibly including
+    /// a trailing comma and erroneous trailing attributes.
     crate fn parse_generic_params(&mut self) -> PResult<'a, Vec<ast::GenericParam>> {
-        let mut lifetimes = Vec::new();
         let mut params = Vec::new();
-        let mut seen_ty_param: Option<Span> = None;
-        let mut last_comma_span = None;
-        let mut bad_lifetime_pos = vec![];
-        let mut suggestions = vec![];
         loop {
             let attrs = self.parse_outer_attributes()?;
             if self.check_lifetime() {
@@ -5226,48 +5662,40 @@ impl<'a> Parser<'a> {
                 } else {
                     Vec::new()
                 };
-                lifetimes.push(ast::GenericParam {
+                params.push(ast::GenericParam {
                     ident: lifetime.ident,
                     id: lifetime.id,
                     attrs: attrs.into(),
                     bounds,
                     kind: ast::GenericParamKind::Lifetime,
                 });
-                if let Some(sp) = seen_ty_param {
-                    let param_span = self.prev_span;
-                    let ate_comma = self.eat(&token::Comma);
-                    let remove_sp = if ate_comma {
-                        param_span.until(self.span)
-                    } else {
-                        last_comma_span.unwrap_or(param_span).to(param_span)
-                    };
-                    bad_lifetime_pos.push(param_span);
-
-                    if let Ok(snippet) = self.sess.source_map().span_to_snippet(param_span) {
-                        suggestions.push((remove_sp, String::new()));
-                        suggestions.push((sp.shrink_to_lo(), format!("{}, ", snippet)));
-                    }
-                    if ate_comma {
-                        last_comma_span = Some(self.prev_span);
-                        continue
-                    }
-                }
+            } else if self.check_keyword(keywords::Const) {
+                // Parse const parameter.
+                params.push(self.parse_const_param(attrs)?);
             } else if self.check_ident() {
                 // Parse type parameter.
                 params.push(self.parse_ty_param(attrs)?);
-                if seen_ty_param.is_none() {
-                    seen_ty_param = Some(self.prev_span);
-                }
             } else {
                 // Check for trailing attributes and stop parsing.
                 if !attrs.is_empty() {
-                    let param_kind = if seen_ty_param.is_some() { "type" } else { "lifetime" };
-                    self.struct_span_err(
-                        attrs[0].span,
-                        &format!("trailing attribute after {} parameters", param_kind),
-                    )
-                    .span_label(attrs[0].span, "attributes must go before parameters")
-                    .emit();
+                    if !params.is_empty() {
+                        self.struct_span_err(
+                            attrs[0].span,
+                            &format!("trailing attribute after generic parameter"),
+                        )
+                        .span_label(attrs[0].span, "attributes must go before parameters")
+                        .emit();
+                    } else {
+                        self.struct_span_err(
+                            attrs[0].span,
+                            &format!("attribute without generic parameters"),
+                        )
+                        .span_label(
+                            attrs[0].span,
+                            "attributes are only permitted when preceding parameters",
+                        )
+                        .emit();
+                    }
                 }
                 break
             }
@@ -5275,27 +5703,11 @@ impl<'a> Parser<'a> {
             if !self.eat(&token::Comma) {
                 break
             }
-            last_comma_span = Some(self.prev_span);
-        }
-        if !bad_lifetime_pos.is_empty() {
-            let mut err = self.struct_span_err(
-                bad_lifetime_pos,
-                "lifetime parameters must be declared prior to type parameters",
-            );
-            if !suggestions.is_empty() {
-                err.multipart_suggestion_with_applicability(
-                    "move the lifetime parameter prior to the first type parameter",
-                    suggestions,
-                    Applicability::MachineApplicable,
-                );
-            }
-            err.emit();
         }
-        lifetimes.extend(params);  // ensure the correct order of lifetimes and type params
-        Ok(lifetimes)
+        Ok(params)
     }
 
-    /// Parse a set of optional generic type parameter declarations. Where
+    /// Parses a set of optional generic type parameter declarations. Where
     /// clauses are not parsed here, and must be added later via
     /// `parse_where_clause()`.
     ///
@@ -5323,31 +5735,167 @@ impl<'a> Parser<'a> {
         }
     }
 
+    /// Parses generic args (within a path segment) with recovery for extra leading angle brackets.
+    /// For the purposes of understanding the parsing logic of generic arguments, this function
+    /// can be thought of being the same as just calling `self.parse_generic_args()` if the source
+    /// had the correct amount of leading angle brackets.
+    ///
+    /// ```ignore (diagnostics)
+    /// bar::<<<<T as Foo>::Output>();
+    ///      ^^ help: remove extra angle brackets
+    /// ```
+    fn parse_generic_args_with_leaning_angle_bracket_recovery(
+        &mut self,
+        style: PathStyle,
+        lo: Span,
+    ) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
+        // We need to detect whether there are extra leading left angle brackets and produce an
+        // appropriate error and suggestion. This cannot be implemented by looking ahead at
+        // upcoming tokens for a matching `>` character - if there are unmatched `<` tokens
+        // then there won't be matching `>` tokens to find.
+        //
+        // To explain how this detection works, consider the following example:
+        //
+        // ```ignore (diagnostics)
+        // bar::<<<<T as Foo>::Output>();
+        //      ^^ help: remove extra angle brackets
+        // ```
+        //
+        // Parsing of the left angle brackets starts in this function. We start by parsing the
+        // `<` token (incrementing the counter of unmatched angle brackets on `Parser` via
+        // `eat_lt`):
+        //
+        // *Upcoming tokens:* `<<<<T as Foo>::Output>;`
+        // *Unmatched count:* 1
+        // *`parse_path_segment` calls deep:* 0
+        //
+        // This has the effect of recursing as this function is called if a `<` character
+        // is found within the expected generic arguments:
+        //
+        // *Upcoming tokens:* `<<<T as Foo>::Output>;`
+        // *Unmatched count:* 2
+        // *`parse_path_segment` calls deep:* 1
+        //
+        // Eventually we will have recursed until having consumed all of the `<` tokens and
+        // this will be reflected in the count:
+        //
+        // *Upcoming tokens:* `T as Foo>::Output>;`
+        // *Unmatched count:* 4
+        // `parse_path_segment` calls deep:* 3
+        //
+        // The parser will continue until reaching the first `>` - this will decrement the
+        // unmatched angle bracket count and return to the parent invocation of this function
+        // having succeeded in parsing:
+        //
+        // *Upcoming tokens:* `::Output>;`
+        // *Unmatched count:* 3
+        // *`parse_path_segment` calls deep:* 2
+        //
+        // This will continue until the next `>` character which will also return successfully
+        // to the parent invocation of this function and decrement the count:
+        //
+        // *Upcoming tokens:* `;`
+        // *Unmatched count:* 2
+        // *`parse_path_segment` calls deep:* 1
+        //
+        // At this point, this function will expect to find another matching `>` character but
+        // won't be able to and will return an error. This will continue all the way up the
+        // call stack until the first invocation:
+        //
+        // *Upcoming tokens:* `;`
+        // *Unmatched count:* 2
+        // *`parse_path_segment` calls deep:* 0
+        //
+        // In doing this, we have managed to work out how many unmatched leading left angle
+        // brackets there are, but we cannot recover as the unmatched angle brackets have
+        // already been consumed. To remedy this, we keep a snapshot of the parser state
+        // before we do the above. We can then inspect whether we ended up with a parsing error
+        // and unmatched left angle brackets and if so, restore the parser state before we
+        // consumed any `<` characters to emit an error and consume the erroneous tokens to
+        // recover by attempting to parse again.
+        //
+        // In practice, the recursion of this function is indirect and there will be other
+        // locations that consume some `<` characters - as long as we update the count when
+        // this happens, it isn't an issue.
+
+        let is_first_invocation = style == PathStyle::Expr;
+        // Take a snapshot before attempting to parse - we can restore this later.
+        let snapshot = if is_first_invocation {
+            Some(self.clone())
+        } else {
+            None
+        };
+
+        debug!("parse_generic_args_with_leading_angle_bracket_recovery: (snapshotting)");
+        match self.parse_generic_args() {
+            Ok(value) => Ok(value),
+            Err(ref mut e) if is_first_invocation && self.unmatched_angle_bracket_count > 0 => {
+                // Cancel error from being unable to find `>`. We know the error
+                // must have been this due to a non-zero unmatched angle bracket
+                // count.
+                e.cancel();
+
+                // Swap `self` with our backup of the parser state before attempting to parse
+                // generic arguments.
+                let snapshot = mem::replace(self, snapshot.unwrap());
+
+                debug!(
+                    "parse_generic_args_with_leading_angle_bracket_recovery: (snapshot failure) \
+                     snapshot.count={:?}",
+                    snapshot.unmatched_angle_bracket_count,
+                );
+
+                // Eat the unmatched angle brackets.
+                for _ in 0..snapshot.unmatched_angle_bracket_count {
+                    self.eat_lt();
+                }
+
+                // Make a span over ${unmatched angle bracket count} characters.
+                let span = lo.with_hi(
+                    lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
+                );
+                let plural = snapshot.unmatched_angle_bracket_count > 1;
+                self.diagnostic()
+                    .struct_span_err(
+                        span,
+                        &format!(
+                            "unmatched angle bracket{}",
+                            if plural { "s" } else { "" }
+                        ),
+                    )
+                    .span_suggestion(
+                        span,
+                        &format!(
+                            "remove extra angle bracket{}",
+                            if plural { "s" } else { "" }
+                        ),
+                        String::new(),
+                        Applicability::MachineApplicable,
+                    )
+                    .emit();
+
+                // Try again without unmatched angle bracket characters.
+                self.parse_generic_args()
+            },
+            Err(e) => Err(e),
+        }
+    }
+
     /// Parses (possibly empty) list of lifetime and type arguments and associated type bindings,
     /// possibly including trailing comma.
     fn parse_generic_args(&mut self) -> PResult<'a, (Vec<GenericArg>, Vec<TypeBinding>)> {
         let mut args = Vec::new();
         let mut bindings = Vec::new();
-        let mut seen_type = false;
-        let mut seen_binding = false;
-        let mut first_type_or_binding_span: Option<Span> = None;
-        let mut bad_lifetime_pos = vec![];
-        let mut last_comma_span = None;
-        let mut suggestions = vec![];
+        let mut misplaced_assoc_ty_bindings: Vec<Span> = Vec::new();
+        let mut assoc_ty_bindings: Vec<Span> = Vec::new();
+
+        let args_lo = self.span;
+
         loop {
             if self.check_lifetime() && self.look_ahead(1, |t| !t.is_like_plus()) {
                 // Parse lifetime argument.
                 args.push(GenericArg::Lifetime(self.expect_lifetime()));
-                if seen_type || seen_binding {
-                    let remove_sp = last_comma_span.unwrap_or(self.prev_span).to(self.prev_span);
-                    bad_lifetime_pos.push(self.prev_span);
-                    if let Ok(snippet) = self.sess.source_map().span_to_snippet(self.prev_span) {
-                        suggestions.push((remove_sp, String::new()));
-                        suggestions.push((
-                            first_type_or_binding_span.unwrap().shrink_to_lo(),
-                            format!("{}, ", snippet)));
-                    }
-                }
+                misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
             } else if self.check_ident() && self.look_ahead(1, |t| t == &token::Eq) {
                 // Parse associated type binding.
                 let lo = self.span;
@@ -5361,63 +5909,67 @@ impl<'a> Parser<'a> {
                     ty,
                     span,
                 });
-                seen_binding = true;
-                if first_type_or_binding_span.is_none() {
-                    first_type_or_binding_span = Some(span);
-                }
+                assoc_ty_bindings.push(span);
+            } else if self.check_const_arg() {
+                // FIXME(const_generics): to distinguish between idents for types and consts,
+                // we should introduce a GenericArg::Ident in the AST and distinguish when
+                // lowering to the HIR. For now, idents for const args are not permitted.
+
+                // Parse const argument.
+                let expr = if let token::OpenDelim(token::Brace) = self.token {
+                    self.parse_block_expr(None, self.span, BlockCheckMode::Default, ThinVec::new())?
+                } else if self.token.is_ident() {
+                    // FIXME(const_generics): to distinguish between idents for types and consts,
+                    // we should introduce a GenericArg::Ident in the AST and distinguish when
+                    // lowering to the HIR. For now, idents for const args are not permitted.
+                    return Err(
+                        self.fatal("identifiers may currently not be used for const generics")
+                    );
+                } else {
+                    // FIXME(const_generics): this currently conflicts with emplacement syntax
+                    // with negative integer literals.
+                    self.parse_literal_maybe_minus()?
+                };
+                let value = AnonConst {
+                    id: ast::DUMMY_NODE_ID,
+                    value: expr,
+                };
+                args.push(GenericArg::Const(value));
+                misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
             } else if self.check_type() {
                 // Parse type argument.
-                let ty_param = self.parse_ty()?;
-                if seen_binding {
-                    self.struct_span_err(
-                        ty_param.span,
-                        "type parameters must be declared prior to associated type bindings"
-                    )
-                        .span_label(
-                            ty_param.span,
-                            "must be declared prior to associated type bindings",
-                        )
-                        .emit();
-                }
-                if first_type_or_binding_span.is_none() {
-                    first_type_or_binding_span = Some(ty_param.span);
-                }
-                args.push(GenericArg::Type(ty_param));
-                seen_type = true;
+                args.push(GenericArg::Type(self.parse_ty()?));
+                misplaced_assoc_ty_bindings.append(&mut assoc_ty_bindings);
             } else {
                 break
             }
 
             if !self.eat(&token::Comma) {
                 break
-            } else {
-                last_comma_span = Some(self.prev_span);
             }
         }
-        if !bad_lifetime_pos.is_empty() {
+
+        // FIXME: we would like to report this in ast_validation instead, but we currently do not
+        // preserve ordering of generic parameters with respect to associated type binding, so we
+        // lose that information after parsing.
+        if misplaced_assoc_ty_bindings.len() > 0 {
             let mut err = self.struct_span_err(
-                bad_lifetime_pos.clone(),
-                "lifetime parameters must be declared prior to type parameters"
+                args_lo.to(self.prev_span),
+                "associated type bindings must be declared after generic parameters",
             );
-            for sp in &bad_lifetime_pos {
-                err.span_label(*sp, "must be declared prior to type parameters");
-            }
-            if !suggestions.is_empty() {
-                err.multipart_suggestion_with_applicability(
-                    &format!(
-                        "move the lifetime parameter{} prior to the first type parameter",
-                        if bad_lifetime_pos.len() > 1 { "s" } else { "" },
-                    ),
-                    suggestions,
-                    Applicability::MachineApplicable,
+            for span in misplaced_assoc_ty_bindings {
+                err.span_label(
+                    span,
+                    "this associated type binding should be moved after the generic parameters",
                 );
             }
             err.emit();
         }
+
         Ok((args, bindings))
     }
 
-    /// Parses an optional `where` clause and places it in `generics`.
+    /// Parses an optional where-clause and places it in `generics`.
     ///
     /// ```ignore (only-for-syntax-highlight)
     /// where T : Trait<U, V> + 'b, 'a : 'b
@@ -5519,7 +6071,7 @@ impl<'a> Parser<'a> {
 
         let sp = self.span;
         let mut variadic = false;
-        let args: Vec<Option<Arg>> =
+        let (args, recovered): (Vec<Option<Arg>>, bool) =
             self.parse_seq_to_before_end(
                 &token::CloseDelim(token::Paren),
                 SeqSep::trailing_allowed(token::Comma),
@@ -5567,7 +6119,9 @@ impl<'a> Parser<'a> {
                 }
             )?;
 
-        self.eat(&token::CloseDelim(token::Paren));
+        if !recovered {
+            self.eat(&token::CloseDelim(token::Paren));
+        }
 
         let args: Vec<_> = args.into_iter().filter_map(|x| x).collect();
 
@@ -5579,7 +6133,7 @@ impl<'a> Parser<'a> {
         Ok((args, variadic))
     }
 
-    /// Parse the argument list and result type of a function declaration
+    /// Parses the argument list and result type of a function declaration.
     fn parse_fn_decl(&mut self, allow_variadic: bool) -> PResult<'a, P<FnDecl>> {
 
         let (args, variadic) = self.parse_fn_args(true, allow_variadic)?;
@@ -5701,7 +6255,7 @@ impl<'a> Parser<'a> {
         Ok(Some(Arg::from_self(eself, eself_ident)))
     }
 
-    /// Parse the parameter list and result type of a function that may have a `self` parameter.
+    /// Parses the parameter list and result type of a function that may have a `self` parameter.
     fn parse_fn_decl_with_self<F>(&mut self, parse_arg_fn: F) -> PResult<'a, P<FnDecl>>
         where F: FnMut(&mut Parser<'a>) -> PResult<'a,  Arg>,
     {
@@ -5712,15 +6266,15 @@ impl<'a> Parser<'a> {
 
         // Parse the rest of the function parameter list.
         let sep = SeqSep::trailing_allowed(token::Comma);
-        let fn_inputs = if let Some(self_arg) = self_arg {
+        let (fn_inputs, recovered) = if let Some(self_arg) = self_arg {
             if self.check(&token::CloseDelim(token::Paren)) {
-                vec![self_arg]
+                (vec![self_arg], false)
             } else if self.eat(&token::Comma) {
                 let mut fn_inputs = vec![self_arg];
-                fn_inputs.append(&mut self.parse_seq_to_before_end(
-                    &token::CloseDelim(token::Paren), sep, parse_arg_fn)?
-                );
-                fn_inputs
+                let (mut input, recovered) = self.parse_seq_to_before_end(
+                    &token::CloseDelim(token::Paren), sep, parse_arg_fn)?;
+                fn_inputs.append(&mut input);
+                (fn_inputs, recovered)
             } else {
                 return self.unexpected();
             }
@@ -5728,8 +6282,10 @@ impl<'a> Parser<'a> {
             self.parse_seq_to_before_end(&token::CloseDelim(token::Paren), sep, parse_arg_fn)?
         };
 
-        // Parse closing paren and return type.
-        self.expect(&token::CloseDelim(token::Paren))?;
+        if !recovered {
+            // Parse closing paren and return type.
+            self.expect(&token::CloseDelim(token::Paren))?;
+        }
         Ok(P(FnDecl {
             inputs: fn_inputs,
             output: self.parse_ret_ty(true)?,
@@ -5737,7 +6293,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    // parse the |arg, arg| header on a lambda
+    /// Parses the `|arg, arg|` header of a closure.
     fn parse_fn_block_decl(&mut self) -> PResult<'a, P<FnDecl>> {
         let inputs_captures = {
             if self.eat(&token::OrOr) {
@@ -5749,7 +6305,7 @@ impl<'a> Parser<'a> {
                     SeqSep::trailing_allowed(token::Comma),
                     TokenExpectType::NoExpect,
                     |p| p.parse_fn_block_arg()
-                )?;
+                )?.0;
                 self.expect_or()?;
                 args
             }
@@ -5763,7 +6319,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Parse the name and optional generic types of a function header.
+    /// Parses the name and optional generic types of a function header.
     fn parse_fn_header(&mut self) -> PResult<'a, (Ident, ast::Generics)> {
         let id = self.parse_ident()?;
         let generics = self.parse_generics()?;
@@ -5783,7 +6339,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse an item-position function declaration.
+    /// Parses an item-position function declaration.
     fn parse_item_fn(&mut self,
                      unsafety: Unsafety,
                      asyncness: IsAsync,
@@ -5798,21 +6354,22 @@ impl<'a> Parser<'a> {
         Ok((ident, ItemKind::Fn(decl, header, generics, body), Some(inner_attrs)))
     }
 
-    /// true if we are looking at `const ID`, false for things like `const fn` etc
+    /// Returns `true` if we are looking at `const ID`
+    /// (returns `false` for things like `const fn`, etc.).
     fn is_const_item(&mut self) -> bool {
         self.token.is_keyword(keywords::Const) &&
             !self.look_ahead(1, |t| t.is_keyword(keywords::Fn)) &&
             !self.look_ahead(1, |t| t.is_keyword(keywords::Unsafe))
     }
 
-    /// parses all the "front matter" for a `fn` declaration, up to
+    /// Parses all the "front matter" for a `fn` declaration, up to
     /// and including the `fn` keyword:
     ///
     /// - `const fn`
     /// - `unsafe fn`
     /// - `const unsafe fn`
     /// - `extern fn`
-    /// - etc
+    /// - etc.
     fn parse_fn_front_matter(&mut self)
         -> PResult<'a, (
             Spanned<Constness>,
@@ -5839,7 +6396,7 @@ impl<'a> Parser<'a> {
         Ok((constness, unsafety, asyncness, abi))
     }
 
-    /// Parse an impl item.
+    /// Parses an impl item.
     pub fn parse_impl_item(&mut self, at_end: &mut bool) -> PResult<'a, ImplItem> {
         maybe_whole!(self, NtImplItem, |x| x);
         let attrs = self.parse_outer_attributes()?;
@@ -5908,7 +6465,7 @@ impl<'a> Parser<'a> {
                 let mut err = if is_macro_rules {
                     let mut err = self.diagnostic()
                         .struct_span_err(sp, "can't qualify macro_rules invocation with `pub`");
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         sp,
                         "try exporting the macro",
                         "#[macro_export]".to_owned(),
@@ -5978,7 +6535,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse `trait Foo { ... }` or `trait Foo = Bar;`
+    /// Parses `trait Foo { ... }` or `trait Foo = Bar;`.
     fn parse_item_trait(&mut self, is_auto: IsAuto, unsafety: Unsafety) -> PResult<'a, ItemInfo> {
         let ident = self.parse_ident()?;
         let mut tps = self.parse_generics()?;
@@ -5995,8 +6552,14 @@ impl<'a> Parser<'a> {
             let bounds = self.parse_generic_bounds()?;
             tps.where_clause = self.parse_where_clause()?;
             self.expect(&token::Semi)?;
+            if is_auto == IsAuto::Yes {
+                let msg = "trait aliases cannot be `auto`";
+                self.struct_span_err(self.prev_span, msg)
+                    .span_label(self.prev_span, msg)
+                    .emit();
+            }
             if unsafety != Unsafety::Normal {
-                let msg = "trait aliases cannot be unsafe";
+                let msg = "trait aliases cannot be `unsafe`";
                 self.struct_span_err(self.prev_span, msg)
                     .span_label(self.prev_span, msg)
                     .emit();
@@ -6034,6 +6597,7 @@ impl<'a> Parser<'a> {
         //     `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
         //     `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
         //     `<` (LIFETIME|IDENT) `=` - generic parameter with a default
+        //     `<` const                - generic const parameter
         // The only truly ambiguous case is
         //     `<` IDENT `>` `::` IDENT ...
         // we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
@@ -6043,7 +6607,8 @@ impl<'a> Parser<'a> {
             (self.look_ahead(1, |t| t == &token::Pound || t == &token::Gt) ||
              self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) &&
                 self.look_ahead(2, |t| t == &token::Gt || t == &token::Comma ||
-                                       t == &token::Colon || t == &token::Eq))
+                                       t == &token::Colon || t == &token::Eq) ||
+             self.look_ahead(1, |t| t.is_keyword(keywords::Const)))
     }
 
     fn parse_impl_body(&mut self) -> PResult<'a, (Vec<ImplItem>, Vec<Attribute>)> {
@@ -6067,9 +6632,11 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses an implementation item, `impl` keyword is already parsed.
+    ///
     ///    impl<'a, T> TYPE { /* impl items */ }
     ///    impl<'a, T> TRAIT for TYPE { /* impl items */ }
     ///    impl<'a, T> !TRAIT for TYPE { /* impl items */ }
+    ///
     /// We actually parse slightly more relaxed grammar for better error reporting and recovery.
     ///     `impl` GENERICS `!`? TYPE `for`? (TYPE | `..`) (`where` PREDICATES)? `{` BODY `}`
     ///     `impl` GENERICS `!`? TYPE (`where` PREDICATES)? `{` BODY `}`
@@ -6116,7 +6683,7 @@ impl<'a> Parser<'a> {
                 // impl Trait for Type
                 if !has_for {
                     self.struct_span_err(missing_for_span, "missing `for` in a trait impl")
-                        .span_suggestion_short_with_applicability(
+                        .span_suggestion_short(
                             missing_for_span,
                             "add `for` here",
                             " for ".to_string(),
@@ -6161,7 +6728,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse struct Foo { ... }
+    /// Parses `struct Foo { ... }`.
     fn parse_item_struct(&mut self) -> PResult<'a, ItemInfo> {
         let class_name = self.parse_ident()?;
 
@@ -6215,7 +6782,7 @@ impl<'a> Parser<'a> {
         Ok((class_name, ItemKind::Struct(vdata, generics), None))
     }
 
-    /// Parse union Foo { ... }
+    /// Parses `union Foo { ... }`.
     fn parse_item_union(&mut self) -> PResult<'a, ItemInfo> {
         let class_name = self.parse_ident()?;
 
@@ -6309,7 +6876,7 @@ impl<'a> Parser<'a> {
         Ok(fields)
     }
 
-    /// Parse a structure field declaration
+    /// Parses a structure field declaration.
     fn parse_single_struct_field(&mut self,
                                      lo: Span,
                                      vis: Visibility,
@@ -6340,7 +6907,7 @@ impl<'a> Parser<'a> {
                 } else {
                     if seen_comma == false {
                         let sp = self.sess.source_map().next_point(previous_span);
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             sp,
                             "missing comma here",
                             ",".into(),
@@ -6356,7 +6923,7 @@ impl<'a> Parser<'a> {
                                                                 self.this_token_descr()));
                 if self.token.is_ident() {
                     // This is likely another field; emit the diagnostic and keep going
-                    err.span_suggestion_with_applicability(
+                    err.span_suggestion(
                         sp,
                         "try adding a comma",
                         ",".into(),
@@ -6371,7 +6938,7 @@ impl<'a> Parser<'a> {
         Ok(a_var)
     }
 
-    /// Parse an element of a struct definition
+    /// Parses an element of a struct declaration.
     fn parse_struct_decl_field(&mut self) -> PResult<'a, StructField> {
         let attrs = self.parse_outer_attributes()?;
         let lo = self.span;
@@ -6379,11 +6946,11 @@ impl<'a> Parser<'a> {
         self.parse_single_struct_field(lo, vis, attrs)
     }
 
-    /// Parse `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
+    /// Parses `pub`, `pub(crate)` and `pub(in path)` plus shortcuts `crate` for `pub(crate)`,
     /// `pub(self)` for `pub(in self)` and `pub(super)` for `pub(in super)`.
-    /// If the following element can't be a tuple (i.e., it's a function definition,
-    /// it's not a tuple struct field) and the contents within the parens
-    /// isn't valid, emit a proper diagnostic.
+    /// If the following element can't be a tuple (i.e., it's a function definition), then
+    /// it's not a tuple struct field), and the contents within the parentheses isn't valid,
+    /// so emit a proper diagnostic.
     pub fn parse_visibility(&mut self, can_take_tuple: bool) -> PResult<'a, Visibility> {
         maybe_whole!(self, NtVis, |x| x);
 
@@ -6454,7 +7021,7 @@ impl<'a> Parser<'a> {
                 self.expect(&token::CloseDelim(token::Paren))?;  // `)`
                 let mut err = struct_span_err!(self.sess.span_diagnostic, sp, E0704, "{}", msg);
                 err.help(suggestion);
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     sp, &help_msg, format!("in {}", path), Applicability::MachineApplicable
                 );
                 err.emit();  // emit diagnostic, but continue with public visibility
@@ -6464,7 +7031,7 @@ impl<'a> Parser<'a> {
         Ok(respan(lo, VisibilityKind::Public))
     }
 
-    /// Parse defaultness: `default` or nothing.
+    /// Parses defaultness (i.e., `default` or nothing).
     fn parse_defaultness(&mut self) -> Defaultness {
         // `pub` is included for better error messages
         if self.check_keyword(keywords::Default) &&
@@ -6485,7 +7052,7 @@ impl<'a> Parser<'a> {
     fn maybe_consume_incorrect_semicolon(&mut self, items: &[P<Item>]) -> bool {
         if self.eat(&token::Semi) {
             let mut err = self.struct_span_err(self.prev_span, "expected item, found `;`");
-            err.span_suggestion_short_with_applicability(
+            err.span_suggestion_short(
                 self.prev_span,
                 "remove this semicolon",
                 String::new(),
@@ -6513,7 +7080,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Given a termination token, parse all of the items in a module
+    /// Given a termination token, parses all of the items in a module.
     fn parse_mod_items(&mut self, term: &token::Token, inner_lo: Span) -> PResult<'a, Mod> {
         let mut items = vec![];
         while let Some(item) = self.parse_item()? {
@@ -6560,11 +7127,12 @@ impl<'a> Parser<'a> {
     /// Parse a `mod <foo> { ... }` or `mod <foo>;` item
     fn parse_item_mod(&mut self, outer_attrs: &[Attribute]) -> PResult<'a, ItemInfo> {
         let (in_cfg, outer_attrs) = {
-            let mut strip_unconfigured = ::config::StripUnconfigured {
+            let mut strip_unconfigured = crate::config::StripUnconfigured {
                 sess: self.sess,
                 features: None, // don't perform gated feature checking
             };
-            let outer_attrs = strip_unconfigured.process_cfg_attrs(outer_attrs.to_owned());
+            let mut outer_attrs = outer_attrs.to_owned();
+            strip_unconfigured.process_cfg_attrs(&mut outer_attrs);
             (!self.cfg_mods || strip_unconfigured.in_cfg(&outer_attrs), outer_attrs)
         };
 
@@ -6649,7 +7217,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Returns either a path to a module, or .
+    /// Returns a path to a module.
     pub fn default_submod_path(
         id: ast::Ident,
         relative: Option<ast::Ident>,
@@ -6792,7 +7360,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Read a module from a source file.
+    /// Reads a module from a source file.
     fn eval_src_mod(&mut self,
                     path: PathBuf,
                     directory_ownership: DirectoryOwnership,
@@ -6824,7 +7392,7 @@ impl<'a> Parser<'a> {
         Ok((m0, mod_attrs))
     }
 
-    /// Parse a function declaration from a foreign module
+    /// Parses a function declaration from a foreign module.
     fn parse_item_foreign_fn(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
                              -> PResult<'a, ForeignItem> {
         self.expect_keyword(keywords::Fn)?;
@@ -6844,7 +7412,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse a static item from a foreign module.
+    /// Parses a static item from a foreign module.
     /// Assumes that the `static` keyword is already parsed.
     fn parse_item_foreign_static(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
                                  -> PResult<'a, ForeignItem> {
@@ -6864,7 +7432,7 @@ impl<'a> Parser<'a> {
         })
     }
 
-    /// Parse a type from a foreign module
+    /// Parses a type from a foreign module.
     fn parse_item_foreign_type(&mut self, vis: ast::Visibility, lo: Span, attrs: Vec<Attribute>)
                              -> PResult<'a, ForeignItem> {
         self.expect_keyword(keywords::Type)?;
@@ -6913,18 +7481,24 @@ impl<'a> Parser<'a> {
 
             let mut err = self.struct_span_err(fixed_name_sp, error_msg);
             err.span_label(fixed_name_sp, "dash-separated idents are not valid");
-            err.multipart_suggestion(suggestion_msg, replacement);
+            err.multipart_suggestion(
+                suggestion_msg,
+                replacement,
+                Applicability::MachineApplicable,
+            );
             err.emit();
         }
         Ok(ident)
     }
 
-    /// Parse extern crate links
+    /// Parses `extern crate` links.
     ///
     /// # Examples
     ///
+    /// ```
     /// extern crate foo;
     /// extern crate bar as foo;
+    /// ```
     fn parse_item_extern_crate(&mut self,
                                lo: Span,
                                visibility: Visibility,
@@ -6943,16 +7517,17 @@ impl<'a> Parser<'a> {
         Ok(self.mk_item(span, item_name, ItemKind::ExternCrate(orig_name), visibility, attrs))
     }
 
-    /// Parse `extern` for foreign ABIs
-    /// modules.
+    /// Parses `extern` for foreign ABIs modules.
     ///
     /// `extern` is expected to have been
-    /// consumed before calling this method
+    /// consumed before calling this method.
     ///
-    /// # Examples:
+    /// # Examples
     ///
+    /// ```ignore (only-for-syntax-highlight)
     /// extern "C" {}
     /// extern {}
+    /// ```
     fn parse_item_foreign_mod(&mut self,
                               lo: Span,
                               opt_abi: Option<Abi>,
@@ -6979,11 +7554,12 @@ impl<'a> Parser<'a> {
         Ok(self.mk_item(lo.to(prev_span), invalid, ItemKind::ForeignMod(m), visibility, attrs))
     }
 
-    /// Parse `type Foo = Bar;`
+    /// Parses `type Foo = Bar;`
     /// or
     /// `existential type Foo: Bar;`
     /// or
-    /// `return None` without modifying the parser state
+    /// `return `None``
+    /// without modifying the parser state.
     fn eat_type(&mut self) -> Option<PResult<'a, (Ident, AliasKind, ast::Generics)>> {
         // This parses the grammar:
         //     Ident ["<"...">"] ["where" ...] ("=" | ":") Ty ";"
@@ -6998,7 +7574,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parse type alias or existential type
+    /// Parses a type alias or existential type.
     fn parse_existential_or_alias(
         &mut self,
         existential: bool,
@@ -7019,7 +7595,7 @@ impl<'a> Parser<'a> {
         Ok((ident, alias, tps))
     }
 
-    /// Parse the part of an "enum" decl following the '{'
+    /// Parses the part of an enum declaration following the `{`.
     fn parse_enum_def(&mut self, _generics: &ast::Generics) -> PResult<'a, EnumDef> {
         let mut variants = Vec::new();
         let mut all_nullary = true;
@@ -7078,7 +7654,7 @@ impl<'a> Parser<'a> {
         Ok(ast::EnumDef { variants })
     }
 
-    /// Parse an "enum" declaration
+    /// Parses an enum declaration.
     fn parse_item_enum(&mut self) -> PResult<'a, ItemInfo> {
         let id = self.parse_ident()?;
         let mut generics = self.parse_generics()?;
@@ -7174,7 +7750,7 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// Parse one of the items allowed by the flags.
+    /// Parses one of the items allowed by the flags.
     fn parse_item_implementation(
         &mut self,
         attrs: Vec<Attribute>,
@@ -7275,9 +7851,16 @@ impl<'a> Parser<'a> {
             // CONST ITEM
             if self.eat_keyword(keywords::Mut) {
                 let prev_span = self.prev_span;
-                self.diagnostic().struct_span_err(prev_span, "const globals cannot be mutable")
-                                 .help("did you mean to declare a static?")
-                                 .emit();
+                let mut err = self.diagnostic()
+                    .struct_span_err(prev_span, "const globals cannot be mutable");
+                err.span_label(prev_span, "cannot be mutable");
+                err.span_suggestion(
+                    const_span,
+                    "you might want to declare a static instead",
+                    "static".to_owned(),
+                    Applicability::MaybeIncorrect,
+                );
+                err.emit();
             }
             let (ident, item_, extra_attrs) = self.parse_item_const(None)?;
             let prev_span = self.prev_span;
@@ -7508,7 +8091,7 @@ impl<'a> Parser<'a> {
                                   ident);
                 let mut err = self.diagnostic()
                     .struct_span_err(sp, "missing `struct` for struct definition");
-                err.span_suggestion_short_with_applicability(
+                err.span_suggestion_short(
                     sp, &msg, " struct ".into(), Applicability::MaybeIncorrect // speculative
                 );
                 return Err(err);
@@ -7543,12 +8126,12 @@ impl<'a> Parser<'a> {
                                              kw,
                                              ident,
                                              kw_name);
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         sp, &suggestion, format!(" {} ", kw), Applicability::MachineApplicable
                     );
                 } else {
                     if let Ok(snippet) = self.sess.source_map().span_to_snippet(ident_sp) {
-                        err.span_suggestion_with_applicability(
+                        err.span_suggestion(
                             full_sp,
                             "if you meant to call a macro, try",
                             format!("{}!", snippet),
@@ -7579,7 +8162,7 @@ impl<'a> Parser<'a> {
                 let msg = format!("missing `{}` for {} definition", kw, kw_name);
                 let mut err = self.diagnostic().struct_span_err(sp, &msg);
                 if !ambiguous {
-                    err.span_suggestion_short_with_applicability(
+                    err.span_suggestion_short(
                         sp,
                         &format!("add `{}` here to parse `{}` as a public {}", kw, ident, kw_name),
                         format!(" {} ", kw),
@@ -7592,7 +8175,7 @@ impl<'a> Parser<'a> {
         self.parse_macro_use_or_failure(attrs, macros_allowed, attributes_allowed, lo, visibility)
     }
 
-    /// Parse a foreign item.
+    /// Parses a foreign item.
     crate fn parse_foreign_item(&mut self) -> PResult<'a, ForeignItem> {
         maybe_whole!(self, NtForeignItem, |ni| ni);
 
@@ -7606,7 +8189,7 @@ impl<'a> Parser<'a> {
             if self.token.is_keyword(keywords::Const) {
                 self.diagnostic()
                     .struct_span_err(self.span, "extern items cannot be `const`")
-                    .span_suggestion_with_applicability(
+                    .span_suggestion(
                         self.span,
                         "try using a static value",
                         "static".to_owned(),
@@ -7640,7 +8223,7 @@ impl<'a> Parser<'a> {
             }
             None => {
                 if !attrs.is_empty()  {
-                    self.expected_item_err(&attrs);
+                    self.expected_item_err(&attrs)?;
                 }
 
                 self.unexpected()
@@ -7703,12 +8286,12 @@ impl<'a> Parser<'a> {
         }
 
         if !attributes_allowed && !attrs.is_empty() {
-            self.expected_item_err(&attrs);
+            self.expected_item_err(&attrs)?;
         }
         Ok(None)
     }
 
-    /// Parse a macro invocation inside a `trait`, `impl` or `extern` block
+    /// Parses a macro invocation inside a `trait`, `impl` or `extern` block.
     fn parse_assoc_macro_invoc(&mut self, item_kind: &str, vis: Option<&Visibility>,
                                at_end: &mut bool) -> PResult<'a, Option<Mac>>
     {
@@ -7734,7 +8317,7 @@ impl<'a> Parser<'a> {
             // eat a matched-delimiter token tree:
             let (delim, tts) = self.expect_delimited_token_tree()?;
             if delim != MacDelimiter::Brace {
-                self.expect(&token::Semi)?
+                self.expect(&token::Semi)?;
             }
 
             Ok(Some(respan(lo.to(self.prev_span), Mac_ { path: pth, tts, delim })))
@@ -7766,7 +8349,7 @@ impl<'a> Parser<'a> {
             &mut self.token_cursor.stack[prev].last_token
         };
 
-        // Pull our the toekns that we've collected from the call to `f` above
+        // Pull out the tokens that we've collected from the call to `f` above.
         let mut collected_tokens = match *last_token {
             LastToken::Collecting(ref mut v) => mem::replace(v, Vec::new()),
             LastToken::Was(_) => panic!("our vector went away?"),
@@ -7785,10 +8368,9 @@ impl<'a> Parser<'a> {
         // call. In that case we need to record all the tokens we collected in
         // our parent list as well. To do that we push a clone of our stream
         // onto the previous list.
-        let stream = collected_tokens.into_iter().collect::<TokenStream>();
         match prev_collecting {
             Some(mut list) => {
-                list.push(stream.clone());
+                list.extend(collected_tokens.iter().cloned());
                 list.extend(extra_token);
                 *last_token = LastToken::Collecting(list);
             }
@@ -7797,7 +8379,7 @@ impl<'a> Parser<'a> {
             }
         }
 
-        Ok((ret?, stream))
+        Ok((ret?, TokenStream::new(collected_tokens)))
     }
 
     pub fn parse_item(&mut self) -> PResult<'a, Option<P<Item>>> {
@@ -7812,13 +8394,15 @@ impl<'a> Parser<'a> {
                                    *t == token::BinOp(token::Star))
     }
 
-    /// Parse UseTree
+    /// Parses a `UseTree`.
     ///
+    /// ```
     /// USE_TREE = [`::`] `*` |
     ///            [`::`] `{` USE_TREE_LIST `}` |
     ///            PATH `::` `*` |
     ///            PATH `::` `{` USE_TREE_LIST `}` |
     ///            PATH [`as` IDENT]
+    /// ```
     fn parse_use_tree(&mut self) -> PResult<'a, UseTree> {
         let lo = self.span;
 
@@ -7857,9 +8441,11 @@ impl<'a> Parser<'a> {
         Ok(UseTree { prefix, kind, span: lo.to(self.prev_span) })
     }
 
-    /// Parse UseTreeKind::Nested(list)
+    /// Parses a `UseTreeKind::Nested(list)`.
     ///
+    /// ```
     /// USE_TREE_LIST = Ø | (USE_TREE `,`)* USE_TREE [`,`]
+    /// ```
     fn parse_use_tree_list(&mut self) -> PResult<'a, Vec<(UseTree, ast::NodeId)>> {
         self.parse_unspanned_seq(&token::OpenDelim(token::Brace),
                                  &token::CloseDelim(token::Brace),
@@ -7876,15 +8462,17 @@ impl<'a> Parser<'a> {
         }
     }
 
-    /// Parses a source module as a crate. This is the main
-    /// entry point for the parser.
+    /// Parses a source module as a crate. This is the main entry point for the parser.
     pub fn parse_crate_mod(&mut self) -> PResult<'a, Crate> {
         let lo = self.span;
-        Ok(ast::Crate {
+        let krate = Ok(ast::Crate {
             attrs: self.parse_inner_attributes()?,
             module: self.parse_mod_items(&token::Eof, lo)?,
             span: lo.to(self.span),
-        })
+        });
+        emit_unclosed_delims(&self.unclosed_delims, self.diagnostic());
+        self.unclosed_delims.clear();
+        krate
     }
 
     pub fn parse_optional_str(&mut self) -> Option<(Symbol, ast::StrStyle, Option<ast::Name>)> {
@@ -7913,3 +8501,20 @@ impl<'a> Parser<'a> {
         }
     }
 }
+
+pub fn emit_unclosed_delims(unclosed_delims: &[UnmatchedBrace], handler: &errors::Handler) {
+    for unmatched in unclosed_delims {
+        let mut err = handler.struct_span_err(unmatched.found_span, &format!(
+            "incorrect close delimiter: `{}`",
+            pprust::token_to_string(&token::Token::CloseDelim(unmatched.found_delim)),
+        ));
+        err.span_label(unmatched.found_span, "incorrect close delimiter");
+        if let Some(sp) = unmatched.candidate_span {
+            err.span_label(sp, "close delimiter possibly meant for this");
+        }
+        if let Some(sp) = unmatched.unclosed_span {
+            err.span_label(sp, "un-closed delimiter");
+        }
+        err.emit();
+    }
+}
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 25a4da38c8c51..ff7f3e0bfaef3 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -1,22 +1,27 @@
-pub use self::BinOpToken::*;
-pub use self::Nonterminal::*;
-pub use self::DelimToken::*;
-pub use self::Lit::*;
-pub use self::Token::*;
-
-use ast::{self};
-use parse::ParseSess;
-use print::pprust;
-use ptr::P;
+pub use BinOpToken::*;
+pub use Nonterminal::*;
+pub use DelimToken::*;
+pub use Lit::*;
+pub use Token::*;
+
+use crate::ast::{self};
+use crate::parse::ParseSess;
+use crate::print::pprust;
+use crate::ptr::P;
+use crate::symbol::keywords;
+use crate::syntax::parse::parse_stream_from_source_str;
+use crate::syntax::parse::parser::emit_unclosed_delims;
+use crate::tokenstream::{self, DelimSpan, TokenStream, TokenTree};
+
 use serialize::{Decodable, Decoder, Encodable, Encoder};
-use symbol::keywords;
-use syntax::parse::parse_stream_from_source_str;
-use syntax_pos::{self, Span, FileName};
 use syntax_pos::symbol::{self, Symbol};
-use tokenstream::{self, DelimSpan, TokenStream, TokenTree};
+use syntax_pos::{self, Span, FileName};
+use log::info;
 
 use std::{cmp, fmt};
 use std::mem;
+#[cfg(target_arch = "x86_64")]
+use rustc_data_structures::static_assert;
 use rustc_data_structures::sync::{Lrc, Lock};
 
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
@@ -33,16 +38,16 @@ pub enum BinOpToken {
     Shr,
 }
 
-/// A delimiter token
+/// A delimiter token.
 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
 pub enum DelimToken {
-    /// A round parenthesis: `(` or `)`
+    /// A round parenthesis (i.e., `(` or `)`).
     Paren,
-    /// A square bracket: `[` or `]`
+    /// A square bracket (i.e., `[` or `]`).
     Bracket,
-    /// A curly brace: `{` or `}`
+    /// A curly brace (i.e., `{` or `}`).
     Brace,
-    /// An empty delimiter
+    /// An empty delimiter.
     NoDelim,
 }
 
@@ -60,6 +65,7 @@ impl DelimToken {
 pub enum Lit {
     Byte(ast::Name),
     Char(ast::Name),
+    Err(ast::Name),
     Integer(ast::Name),
     Float(ast::Name),
     Str_(ast::Name),
@@ -73,6 +79,7 @@ impl Lit {
         match *self {
             Byte(_) => "byte literal",
             Char(_) => "char literal",
+            Err(_) => "invalid literal",
             Integer(_) => "integer literal",
             Float(_) => "float literal",
             Str_(_) | StrRaw(..) => "string literal",
@@ -165,9 +172,9 @@ pub enum Token {
     Question,
     /// Used by proc macros for representing lifetimes, not generated by lexer right now.
     SingleQuote,
-    /// An opening delimiter, eg. `{`
+    /// An opening delimiter (e.g., `{`).
     OpenDelim(DelimToken),
-    /// A closing delimiter, eg. `}`
+    /// A closing delimiter (e.g., `}`).
     CloseDelim(DelimToken),
 
     /* Literals */
@@ -181,16 +188,16 @@ pub enum Token {
     // and so the `LazyTokenStream` can be ignored by Eq, Hash, etc.
     Interpolated(Lrc<(Nonterminal, LazyTokenStream)>),
     // Can be expanded into several tokens.
-    /// Doc comment
+    /// A doc comment.
     DocComment(ast::Name),
 
     // Junk. These carry no data because we don't really care about the data
     // they *would* carry, and don't really want to allocate a new ident for
     // them. Instead, users could extract that from the associated span.
 
-    /// Whitespace
+    /// Whitespace.
     Whitespace,
-    /// Comment
+    /// A comment.
     Comment,
     Shebang(ast::Name),
 
@@ -273,6 +280,20 @@ impl Token {
         }
     }
 
+    /// Returns `true` if the token can appear at the start of a const param.
+    pub fn can_begin_const_arg(&self) -> bool {
+        match self {
+            OpenDelim(Brace) => true,
+            Interpolated(ref nt) => match nt.0 {
+                NtExpr(..) => true,
+                NtBlock(..) => true,
+                NtLiteral(..) => true,
+                _ => false,
+            }
+            _ => self.can_begin_literal_or_bool(),
+        }
+    }
+
     /// Returns `true` if the token can appear at the start of a generic bound.
     crate fn can_begin_bound(&self) -> bool {
         self.is_path_start() || self.is_lifetime() || self.is_keyword(keywords::For) ||
@@ -287,7 +308,7 @@ impl Token {
         }
     }
 
-    /// Returns `true` if the token is any literal, a minus (which can follow a literal,
+    /// Returns `true` if the token is any literal, a minus (which can prefix a literal,
     /// for example a '-42', or one of the boolean idents).
     crate fn can_begin_literal_or_bool(&self) -> bool {
         match *self {
@@ -471,8 +492,7 @@ impl Token {
 
             Le | EqEq | Ne | Ge | AndAnd | OrOr | Tilde | BinOpEq(..) | At | DotDotDot |
             DotDotEq | Comma | Semi | ModSep | RArrow | LArrow | FatArrow | Pound | Dollar |
-            Question | OpenDelim(..) | CloseDelim(..) => return None,
-
+            Question | OpenDelim(..) | CloseDelim(..) |
             Literal(..) | Ident(..) | Lifetime(..) | Interpolated(..) | DocComment(..) |
             Whitespace | Comment | Shebang(..) | Eof => return None,
         })
@@ -482,8 +502,8 @@ impl Token {
     /// Enables better error recovery when the wrong token is found.
     crate fn similar_tokens(&self) -> Option<Vec<Token>> {
         match *self {
-            Comma => Some(vec![Dot, Lt]),
-            Semi => Some(vec![Colon]),
+            Comma => Some(vec![Dot, Lt, Semi]),
+            Semi => Some(vec![Colon, Comma]),
             _ => None
         }
     }
@@ -540,7 +560,10 @@ impl Token {
             // FIXME(#43081): Avoid this pretty-print + reparse hack
             let source = pprust::token_to_string(self);
             let filename = FileName::macro_expansion_source_code(&source);
-            parse_stream_from_source_str(filename, source, sess, Some(span))
+            let (tokens, errors) = parse_stream_from_source_str(
+                filename, source, sess, Some(span));
+            emit_unclosed_delims(&errors, &sess.span_diagnostic);
+            tokens
         });
 
         // During early phases of the compiler the AST could get modified
@@ -682,7 +705,7 @@ impl PartialEq for Nonterminal {
 }
 
 impl fmt::Debug for Nonterminal {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             NtItem(..) => f.pad("NtItem(..)"),
             NtBlock(..) => f.pad("NtBlock(..)"),
@@ -728,13 +751,13 @@ impl PartialEq for LazyTokenStream {
 }
 
 impl fmt::Debug for LazyTokenStream {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(&self.clone().0.into_inner(), f)
     }
 }
 
 impl LazyTokenStream {
-    fn new() -> Self {
+    pub fn new() -> Self {
         LazyTokenStream(Lock::new(None))
     }
 
@@ -781,12 +804,13 @@ fn prepend_attrs(sess: &ParseSess,
         let source = pprust::attr_to_string(attr);
         let macro_filename = FileName::macro_expansion_source_code(&source);
         if attr.is_sugared_doc {
-            let stream = parse_stream_from_source_str(
+            let (stream, errors) = parse_stream_from_source_str(
                 macro_filename,
                 source,
                 sess,
                 Some(span),
             );
+            emit_unclosed_delims(&errors, &sess.span_diagnostic);
             builder.push(stream);
             continue
         }
@@ -803,12 +827,13 @@ fn prepend_attrs(sess: &ParseSess,
         // ... and for more complicated paths, fall back to a reparse hack that
         // should eventually be removed.
         } else {
-            let stream = parse_stream_from_source_str(
+            let (stream, errors) = parse_stream_from_source_str(
                 macro_filename,
                 source,
                 sess,
                 Some(span),
             );
+            emit_unclosed_delims(&errors, &sess.span_diagnostic);
             brackets.push(stream);
         }
 
diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index 5232b8333e6ae..d8a8cbb655b4b 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -1,10 +1,10 @@
 //! This pretty-printer is a direct reimplementation of Philip Karlton's
 //! Mesa pretty-printer, as described in appendix A of
 //!
-//! ````text
+//! ```text
 //! STAN-CS-79-770: "Pretty Printing", by Derek C. Oppen.
 //! Stanford Department of Computer Science, 1979.
-//! ````
+//! ```
 //!
 //! The algorithm's aim is to break a stream into as few lines as possible
 //! while respecting the indentation-consistency requirements of the enclosing
@@ -138,6 +138,7 @@ use std::collections::VecDeque;
 use std::fmt;
 use std::io;
 use std::borrow::Cow;
+use log::debug;
 
 /// How to break. Described in more detail in the module docs.
 #[derive(Clone, Copy, PartialEq)]
@@ -192,7 +193,7 @@ impl Token {
 }
 
 impl fmt::Display for Token {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             Token::String(ref s, len) => write!(f, "STR({},{})", s, len),
             Token::Break(_) => f.write_str("BREAK"),
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index 2ad3d3a6d6487..cdf805176a293 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -1,21 +1,22 @@
+use crate::ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
+use crate::ast::{SelfKind, GenericBound, TraitBoundModifier};
+use crate::ast::{Attribute, MacDelimiter, GenericArg};
+use crate::util::parser::{self, AssocOp, Fixity};
+use crate::attr;
+use crate::source_map::{self, SourceMap, Spanned};
+use crate::parse::token::{self, BinOpToken, Token};
+use crate::parse::lexer::comments;
+use crate::parse::{self, ParseSess};
+use crate::print::pp::{self, Breaks};
+use crate::print::pp::Breaks::{Consistent, Inconsistent};
+use crate::ptr::P;
+use crate::std_inject;
+use crate::symbol::keywords;
+use crate::tokenstream::{self, TokenStream, TokenTree};
+
 use rustc_target::spec::abi::{self, Abi};
-use ast::{self, BlockCheckMode, PatKind, RangeEnd, RangeSyntax};
-use ast::{SelfKind, GenericBound, TraitBoundModifier};
-use ast::{Attribute, MacDelimiter, GenericArg};
-use util::parser::{self, AssocOp, Fixity};
-use attr;
-use source_map::{self, SourceMap, Spanned};
 use syntax_pos::{self, BytePos};
-use parse::token::{self, BinOpToken, Token};
-use parse::lexer::comments;
-use parse::{self, ParseSess};
-use print::pp::{self, Breaks};
-use print::pp::Breaks::{Consistent, Inconsistent};
-use ptr::P;
-use std_inject;
-use symbol::keywords;
 use syntax_pos::{DUMMY_SP, FileName};
-use tokenstream::{self, TokenStream, TokenTree};
 
 use std::ascii;
 use std::borrow::Cow;
@@ -34,8 +35,8 @@ pub enum AnnNode<'a> {
 }
 
 pub trait PpAnn {
-    fn pre(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
-    fn post(&self, _state: &mut State, _node: AnnNode) -> io::Result<()> { Ok(()) }
+    fn pre(&self, _state: &mut State<'_>, _node: AnnNode<'_>) -> io::Result<()> { Ok(()) }
+    fn post(&self, _state: &mut State<'_>, _node: AnnNode<'_>) -> io::Result<()> { Ok(()) }
 }
 
 #[derive(Copy, Clone)]
@@ -150,7 +151,7 @@ impl<'a> State<'a> {
 }
 
 pub fn to_string<F>(f: F) -> String where
-    F: FnOnce(&mut State) -> io::Result<()>,
+    F: FnOnce(&mut State<'_>) -> io::Result<()>,
 {
     let mut wr = Vec::new();
     {
@@ -224,6 +225,7 @@ pub fn token_to_string(tok: &Token) -> String {
             let mut out = match lit {
                 token::Byte(b)           => format!("b'{}'", b),
                 token::Char(c)           => format!("'{}'", c),
+                token::Err(c)            => format!("'{}'", c),
                 token::Float(c)          |
                 token::Integer(c)        => c.to_string(),
                 token::Str_(s)           => format!("\"{}\"", s),
@@ -603,6 +605,14 @@ pub trait PrintState<'a> {
         }
         match lit.node {
             ast::LitKind::Str(st, style) => self.print_string(&st.as_str(), style),
+            ast::LitKind::Err(st) => {
+                let st = st.as_str().escape_debug().to_string();
+                let mut res = String::with_capacity(st.len() + 2);
+                res.push('\'');
+                res.push_str(&st);
+                res.push('\'');
+                self.writer().word(res)
+            }
             ast::LitKind::Byte(byte) => {
                 let mut res = String::from("b'");
                 res.extend(ascii::escape_default(byte).map(|c| c as char));
@@ -807,7 +817,7 @@ pub trait PrintState<'a> {
             TokenTree::Delimited(_, delim, tts) => {
                 self.writer().word(token_to_string(&token::OpenDelim(delim)))?;
                 self.writer().space()?;
-                self.print_tts(tts.stream())?;
+                self.print_tts(tts)?;
                 self.writer().space()?;
                 self.writer().word(token_to_string(&token::CloseDelim(delim)))
             },
@@ -960,7 +970,7 @@ impl<'a> State<'a> {
                                   elts: &[T],
                                   mut op: F,
                                   mut get_span: G) -> io::Result<()> where
-        F: FnMut(&mut State, &T) -> io::Result<()>,
+        F: FnMut(&mut State<'_>, &T) -> io::Result<()>,
         G: FnMut(&T) -> syntax_pos::Span,
     {
         self.rbox(0, b)?;
@@ -1015,6 +1025,7 @@ impl<'a> State<'a> {
         match generic_arg {
             GenericArg::Lifetime(lt) => self.print_lifetime(*lt),
             GenericArg::Type(ty) => self.print_type(ty),
+            GenericArg::Const(ct) => self.print_expr(&ct.value),
         }
     }
 
@@ -2919,7 +2930,7 @@ impl<'a> State<'a> {
                     s.print_outer_attributes_inline(&param.attrs)?;
                     let lt = ast::Lifetime { id: param.id, ident: param.ident };
                     s.print_lifetime_bounds(lt, &param.bounds)
-                },
+                }
                 ast::GenericParamKind::Type { ref default } => {
                     s.print_outer_attributes_inline(&param.attrs)?;
                     s.print_ident(param.ident)?;
@@ -2933,6 +2944,15 @@ impl<'a> State<'a> {
                         _ => Ok(())
                     }
                 }
+                ast::GenericParamKind::Const { ref ty } => {
+                    s.print_outer_attributes_inline(&param.attrs)?;
+                    s.word_space("const")?;
+                    s.print_ident(param.ident)?;
+                    s.s.space()?;
+                    s.word_space(":")?;
+                    s.print_type(ty)?;
+                    s.print_type_bounds(":", &param.bounds)
+                }
             }
         })?;
 
@@ -3201,10 +3221,10 @@ impl<'a> State<'a> {
 mod tests {
     use super::*;
 
-    use ast;
-    use source_map;
+    use crate::ast;
+    use crate::source_map;
+    use crate::with_globals;
     use syntax_pos;
-    use with_globals;
 
     #[test]
     fn test_fun_to_string() {
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index bb1744e2df169..bc43630ae59b3 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -1,4 +1,4 @@
-//! The AST pointer
+//! The AST pointer.
 //!
 //! Provides `P<T>`, a frozen owned smart pointer, as a replacement for `@T` in
 //! the AST.
@@ -101,6 +101,7 @@ impl<T: 'static> P<T> {
                 // Recreate self from the raw pointer.
                 Some(P { ptr: Box::from_raw(p) })
             } else {
+                drop(Box::from_raw(p));
                 None
             }
         }
@@ -128,19 +129,19 @@ impl<T: 'static + Clone> Clone for P<T> {
 }
 
 impl<T: ?Sized + Debug> Debug for P<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Debug::fmt(&self.ptr, f)
     }
 }
 
 impl<T: Display> Display for P<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         Display::fmt(&**self, f)
     }
 }
 
 impl<T> fmt::Pointer for P<T> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Pointer::fmt(&self.ptr, f)
     }
 }
diff --git a/src/libsyntax/show_span.rs b/src/libsyntax/show_span.rs
index 4228e0c87ce33..5e0cf9eea78b8 100644
--- a/src/libsyntax/show_span.rs
+++ b/src/libsyntax/show_span.rs
@@ -5,10 +5,9 @@
 
 use std::str::FromStr;
 
-use ast;
-use errors;
-use visit;
-use visit::Visitor;
+use crate::ast;
+use crate::visit;
+use crate::visit::Visitor;
 
 enum Mode {
     Expression,
diff --git a/src/libsyntax/source_map.rs b/src/libsyntax/source_map.rs
index 0a46d03455819..62a6972122abd 100644
--- a/src/libsyntax/source_map.rs
+++ b/src/libsyntax/source_map.rs
@@ -10,7 +10,7 @@
 
 pub use syntax_pos::*;
 pub use syntax_pos::hygiene::{ExpnFormat, ExpnInfo};
-pub use self::ExpnFormat::*;
+pub use ExpnFormat::*;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::stable_hasher::StableHasher;
@@ -22,9 +22,11 @@ use std::path::{Path, PathBuf};
 use std::env;
 use std::fs;
 use std::io;
+use log::debug;
+
 use errors::SourceMapper;
 
-/// Return the span itself if it doesn't come from a macro expansion,
+/// Returns the span itself if it doesn't come from a macro expansion,
 /// otherwise return the call site span up to the `enclosing_sp` by
 /// following the `expn_info` chain.
 pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span {
@@ -60,7 +62,7 @@ pub trait FileLoader {
     /// Query the existence of a file.
     fn file_exists(&self, path: &Path) -> bool;
 
-    /// Return an absolute path to a file, if possible.
+    /// Returns an absolute path to a file, if possible.
     fn abs_path(&self, path: &Path) -> Option<PathBuf>;
 
     /// Read the contents of an UTF-8 file into memory.
@@ -167,7 +169,7 @@ impl SourceMap {
         Ok(self.new_source_file(filename, src))
     }
 
-    pub fn files(&self) -> MappedLockGuard<Vec<Lrc<SourceFile>>> {
+    pub fn files(&self) -> MappedLockGuard<'_, Vec<Lrc<SourceFile>>> {
         LockGuard::map(self.files.borrow(), |files| &mut files.source_files)
     }
 
@@ -396,7 +398,7 @@ impl SourceMap {
         }
     }
 
-    /// Returns `Some(span)`, a union of the lhs and rhs span.  The lhs must precede the rhs. If
+    /// Returns `Some(span)`, a union of the lhs and rhs span. The lhs must precede the rhs. If
     /// there are gaps between lhs and rhs, the resulting union will cross these gaps.
     /// For this to work, the spans have to be:
     ///
@@ -509,7 +511,7 @@ impl SourceMap {
         Ok(FileLines {file: lo.file, lines: lines})
     }
 
-    /// Extract the source surrounding the given `Span` using the `extract_source` function. The
+    /// Extracts the source surrounding the given `Span` using the `extract_source` function. The
     /// extract function takes three arguments: a string slice containing the source, an index in
     /// the slice for the beginning of the span and an index in the slice for the end of the span.
     fn span_to_source<F>(&self, sp: Span, extract_source: F) -> Result<String, SpanSnippetError>
@@ -559,7 +561,7 @@ impl SourceMap {
         }
     }
 
-    /// Return the source snippet as `String` corresponding to the given `Span`
+    /// Returns the source snippet as `String` corresponding to the given `Span`
     pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> {
         self.span_to_source(sp, |src, start_index, end_index| src[start_index..end_index]
                                                                 .to_string())
@@ -574,7 +576,7 @@ impl SourceMap {
         }
     }
 
-    /// Return the source snippet as `String` before the given `Span`
+    /// Returns the source snippet as `String` before the given `Span`
     pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError> {
         self.span_to_source(sp, |src, start_index, _| src[..start_index].to_string())
     }
@@ -1121,7 +1123,7 @@ mod tests {
 
     /// Given a string like " ~~~~~~~~~~~~ ", produces a span
     /// converting that range. The idea is that the string has the same
-    /// length as the input, and we uncover the byte positions.  Note
+    /// length as the input, and we uncover the byte positions. Note
     /// that this can span lines and so on.
     fn span_from_selection(input: &str, selection: &str) -> Span {
         assert_eq!(input.len(), selection.len());
@@ -1130,7 +1132,7 @@ mod tests {
         Span::new(BytePos(left_index), BytePos(right_index + 1), NO_EXPANSION)
     }
 
-    /// Test span_to_snippet and span_to_lines for a span converting 3
+    /// Tests span_to_snippet and span_to_lines for a span converting 3
     /// lines in the middle of a file.
     #[test]
     fn span_to_snippet_and_lines_spanning_multiple_lines() {
@@ -1173,7 +1175,7 @@ mod tests {
         assert_eq!(sstr, "blork.rs:2:1: 2:12");
     }
 
-    /// Test failing to merge two spans on different lines
+    /// Tests failing to merge two spans on different lines
     #[test]
     fn span_merging_fail() {
         let sm = SourceMap::new(FilePathMapping::empty());
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
index e0770834421b8..b9758bd655c15 100644
--- a/src/libsyntax/std_inject.rs
+++ b/src/libsyntax/std_inject.rs
@@ -1,14 +1,15 @@
-use ast;
-use attr;
+use crate::ast;
+use crate::attr;
+use crate::edition::Edition;
+use crate::ext::hygiene::{Mark, SyntaxContext};
+use crate::symbol::{Symbol, keywords};
+use crate::source_map::{ExpnInfo, MacroAttribute, dummy_spanned, hygiene, respan};
+use crate::ptr::P;
+use crate::tokenstream::TokenStream;
+
 use std::cell::Cell;
 use std::iter;
-use edition::Edition;
-use ext::hygiene::{Mark, SyntaxContext};
-use symbol::{Symbol, keywords};
 use syntax_pos::{DUMMY_SP, Span};
-use source_map::{ExpnInfo, MacroAttribute, dummy_spanned, hygiene, respan};
-use ptr::P;
-use tokenstream::TokenStream;
 
 /// Craft a span that will be ignored by the stability lint's
 /// call to source_map's `is_internal` check.
@@ -19,7 +20,9 @@ fn ignored_span(sp: Span) -> Span {
         call_site: DUMMY_SP,
         def_site: None,
         format: MacroAttribute(Symbol::intern("std_inject")),
-        allow_internal_unstable: true,
+        allow_internal_unstable: Some(vec![
+            Symbol::intern("prelude_import"),
+        ].into()),
         allow_internal_unsafe: false,
         local_inner_macros: false,
         edition: hygiene::default_edition(),
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index b352486e39a64..56290fa771ba9 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -3,34 +3,34 @@
 #![allow(dead_code)]
 #![allow(unused_imports)]
 
-use self::HasTestSignature::*;
+use HasTestSignature::*;
 
 use std::iter;
 use std::slice;
 use std::mem;
 use std::vec;
-use attr::{self, HasAttrs};
-use syntax_pos::{self, DUMMY_SP, NO_EXPANSION, Span, SourceFile, BytePos};
-
-use source_map::{self, SourceMap, ExpnInfo, MacroAttribute, dummy_spanned, respan};
-use errors;
-use config;
-use entry::{self, EntryPointType};
-use ext::base::{ExtCtxt, Resolver};
-use ext::build::AstBuilder;
-use ext::expand::ExpansionConfig;
-use ext::hygiene::{self, Mark, SyntaxContext};
-use fold::Folder;
-use feature_gate::Features;
-use util::move_map::MoveMap;
-use fold::{self, ExpectOne};
-use parse::{token, ParseSess};
-use print::pprust;
-use ast::{self, Ident};
-use ptr::P;
-use smallvec::SmallVec;
-use symbol::{self, Symbol, keywords};
-use ThinVec;
+
+use log::debug;
+use smallvec::{smallvec, SmallVec};
+use syntax_pos::{DUMMY_SP, NO_EXPANSION, Span, SourceFile, BytePos};
+
+use crate::attr::{self, HasAttrs};
+use crate::source_map::{self, SourceMap, ExpnInfo, MacroAttribute, dummy_spanned, respan};
+use crate::config;
+use crate::entry::{self, EntryPointType};
+use crate::ext::base::{ExtCtxt, Resolver};
+use crate::ext::build::AstBuilder;
+use crate::ext::expand::ExpansionConfig;
+use crate::ext::hygiene::{self, Mark, SyntaxContext};
+use crate::mut_visit::{*, ExpectOne};
+use crate::feature_gate::Features;
+use crate::util::map_in_place::MapInPlace;
+use crate::parse::{token, ParseSess};
+use crate::print::pprust;
+use crate::ast::{self, Ident};
+use crate::ptr::P;
+use crate::symbol::{self, Symbol, keywords};
+use crate::ThinVec;
 
 struct Test {
     span: Span,
@@ -57,9 +57,9 @@ struct TestCtxt<'a> {
 pub fn modify_for_testing(sess: &ParseSess,
                           resolver: &mut dyn Resolver,
                           should_test: bool,
-                          krate: ast::Crate,
+                          krate: &mut ast::Crate,
                           span_diagnostic: &errors::Handler,
-                          features: &Features) -> ast::Crate {
+                          features: &Features) {
     // Check for #[reexport_test_harness_main = "some_name"] which
     // creates a `use __test::main as some_name;`. This needs to be
     // unconditional, so that the attribute is still marked as used in
@@ -75,8 +75,6 @@ pub fn modify_for_testing(sess: &ParseSess,
     if should_test {
         generate_test_harness(sess, resolver, reexport_test_harness_main,
                               krate, span_diagnostic, features, test_runner)
-    } else {
-        krate
     }
 }
 
@@ -88,21 +86,20 @@ struct TestHarnessGenerator<'a> {
     tested_submods: Vec<(Ident, Ident)>,
 }
 
-impl<'a> fold::Folder for TestHarnessGenerator<'a> {
-    fn fold_crate(&mut self, c: ast::Crate) -> ast::Crate {
-        let mut folded = fold::noop_fold_crate(c, self);
+impl<'a> MutVisitor for TestHarnessGenerator<'a> {
+    fn visit_crate(&mut self, c: &mut ast::Crate) {
+        noop_visit_crate(c, self);
 
         // Create a main function to run our tests
         let test_main = {
             let unresolved = mk_main(&mut self.cx);
-            self.cx.ext_cx.monotonic_expander().fold_item(unresolved).pop().unwrap()
+            self.cx.ext_cx.monotonic_expander().flat_map_item(unresolved).pop().unwrap()
         };
 
-        folded.module.items.push(test_main);
-        folded
+        c.module.items.push(test_main);
     }
 
-    fn fold_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
+    fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
         let ident = i.ident;
         if ident.name != keywords::Invalid.name() {
             self.cx.path.push(ident);
@@ -123,16 +120,16 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
 
         // We don't want to recurse into anything other than mods, since
         // mods or tests inside of functions will break things
-        if let ast::ItemKind::Mod(module) = item.node {
+        if let ast::ItemKind::Mod(mut module) = item.node {
             let tests = mem::replace(&mut self.tests, Vec::new());
             let tested_submods = mem::replace(&mut self.tested_submods, Vec::new());
-            let mut mod_folded = fold::noop_fold_mod(module, self);
+            noop_visit_mod(&mut module, self);
             let tests = mem::replace(&mut self.tests, tests);
             let tested_submods = mem::replace(&mut self.tested_submods, tested_submods);
 
             if !tests.is_empty() || !tested_submods.is_empty() {
                 let (it, sym) = mk_reexport_mod(&mut self.cx, item.id, tests, tested_submods);
-                mod_folded.items.push(it);
+                module.items.push(it);
 
                 if !self.cx.path.is_empty() {
                     self.tested_submods.push((self.cx.path[self.cx.path.len()-1], sym));
@@ -141,7 +138,7 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
                     self.cx.toplevel_reexport = Some(sym);
                 }
             }
-            item.node = ast::ItemKind::Mod(mod_folded);
+            item.node = ast::ItemKind::Mod(module);
         }
         if ident.name != keywords::Invalid.name() {
             self.cx.path.pop();
@@ -149,7 +146,9 @@ impl<'a> fold::Folder for TestHarnessGenerator<'a> {
         smallvec![P(item)]
     }
 
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { mac }
+    fn visit_mac(&mut self, _mac: &mut ast::Mac) {
+        // Do nothing.
+    }
 }
 
 /// A folder used to remove any entry points (like fn main) because the harness
@@ -159,20 +158,20 @@ struct EntryPointCleaner {
     depth: usize,
 }
 
-impl fold::Folder for EntryPointCleaner {
-    fn fold_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
+impl MutVisitor for EntryPointCleaner {
+    fn flat_map_item(&mut self, i: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
         self.depth += 1;
-        let folded = fold::noop_fold_item(i, self).expect_one("noop did something");
+        let item = noop_flat_map_item(i, self).expect_one("noop did something");
         self.depth -= 1;
 
         // Remove any #[main] or #[start] from the AST so it doesn't
         // clash with the one we're going to add, but mark it as
         // #[allow(dead_code)] to avoid printing warnings.
-        let folded = match entry::entry_point_type(&folded, self.depth) {
+        let item = match entry::entry_point_type(&item, self.depth) {
             EntryPointType::MainNamed |
             EntryPointType::MainAttr |
             EntryPointType::Start =>
-                folded.map(|ast::Item {id, ident, attrs, node, vis, span, tokens}| {
+                item.map(|ast::Item {id, ident, attrs, node, vis, span, tokens}| {
                     let allow_ident = Ident::from_str("allow");
                     let dc_nested = attr::mk_nested_word_item(Ident::from_str("dead_code"));
                     let allow_dead_code_item = attr::mk_list_item(DUMMY_SP, allow_ident,
@@ -197,20 +196,22 @@ impl fold::Folder for EntryPointCleaner {
                     }
                 }),
             EntryPointType::None |
-            EntryPointType::OtherMain => folded,
+            EntryPointType::OtherMain => item,
         };
 
-        smallvec![folded]
+        smallvec![item]
     }
 
-    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { mac }
+    fn visit_mac(&mut self, _mac: &mut ast::Mac) {
+        // Do nothing.
+    }
 }
 
 /// Creates an item (specifically a module) that "pub use"s the tests passed in.
 /// Each tested submodule will contain a similar reexport module that we will export
 /// under the name of the original module. That is, `submod::__test_reexports` is
 /// reexported like so `pub use submod::__test_reexports as submod`.
-fn mk_reexport_mod(cx: &mut TestCtxt,
+fn mk_reexport_mod(cx: &mut TestCtxt<'_>,
                    parent: ast::NodeId,
                    tests: Vec<Ident>,
                    tested_submods: Vec<(Ident, Ident)>)
@@ -235,7 +236,7 @@ fn mk_reexport_mod(cx: &mut TestCtxt,
     let sym = Ident::with_empty_ctxt(Symbol::gensym("__test_reexports"));
     let parent = if parent == ast::DUMMY_NODE_ID { ast::CRATE_NODE_ID } else { parent };
     cx.ext_cx.current_expansion.mark = cx.ext_cx.resolver.get_module_scope(parent);
-    let it = cx.ext_cx.monotonic_expander().fold_item(P(ast::Item {
+    let it = cx.ext_cx.monotonic_expander().flat_map_item(P(ast::Item {
         ident: sym,
         attrs: Vec::new(),
         id: ast::DUMMY_NODE_ID,
@@ -252,13 +253,13 @@ fn mk_reexport_mod(cx: &mut TestCtxt,
 fn generate_test_harness(sess: &ParseSess,
                          resolver: &mut dyn Resolver,
                          reexport_test_harness_main: Option<Symbol>,
-                         krate: ast::Crate,
+                         krate: &mut ast::Crate,
                          sd: &errors::Handler,
                          features: &Features,
-                         test_runner: Option<ast::Path>) -> ast::Crate {
+                         test_runner: Option<ast::Path>) {
     // Remove the entry points
     let mut cleaner = EntryPointCleaner { depth: 0 };
-    let krate = cleaner.fold_crate(krate);
+    cleaner.visit_crate(krate);
 
     let mark = Mark::fresh(Mark::root());
 
@@ -283,7 +284,11 @@ fn generate_test_harness(sess: &ParseSess,
         call_site: DUMMY_SP,
         def_site: None,
         format: MacroAttribute(Symbol::intern("test_case")),
-        allow_internal_unstable: true,
+        allow_internal_unstable: Some(vec![
+            Symbol::intern("main"),
+            Symbol::intern("test"),
+            Symbol::intern("rustc_attrs"),
+        ].into()),
         allow_internal_unsafe: false,
         local_inner_macros: false,
         edition: hygiene::default_edition(),
@@ -293,13 +298,13 @@ fn generate_test_harness(sess: &ParseSess,
         cx,
         tests: Vec::new(),
         tested_submods: Vec::new(),
-    }.fold_crate(krate)
+    }.visit_crate(krate);
 }
 
 /// Craft a span that will be ignored by the stability lint's
 /// call to source_map's `is_internal` check.
 /// The expanded code calls some unstable functions in the test crate.
-fn ignored_span(cx: &TestCtxt, sp: Span) -> Span {
+fn ignored_span(cx: &TestCtxt<'_>, sp: Span) -> Span {
     sp.with_ctxt(cx.ctxt)
 }
 
@@ -318,7 +323,7 @@ enum BadTestSignature {
 
 /// Creates a function item for use as the main function of a test build.
 /// This function will call the `test_runner` as specified by the crate attribute
-fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
+fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
     // Writing this out by hand with 'ignored_span':
     //        pub fn main() {
     //            #![main]
@@ -398,7 +403,7 @@ fn path_name_i(idents: &[Ident]) -> String {
 
 /// Creates a slice containing every test like so:
 /// &[path::to::test1, path::to::test2]
-fn mk_tests_slice(cx: &TestCtxt) -> P<ast::Expr> {
+fn mk_tests_slice(cx: &TestCtxt<'_>) -> P<ast::Expr> {
     debug!("building test vector from {} tests", cx.test_cases.len());
     let ref ecx = cx.ext_cx;
 
@@ -410,7 +415,7 @@ fn mk_tests_slice(cx: &TestCtxt) -> P<ast::Expr> {
 }
 
 /// Creates a path from the top-level __test module to the test via __test_reexports
-fn visible_path(cx: &TestCtxt, path: &[Ident]) -> Vec<Ident>{
+fn visible_path(cx: &TestCtxt<'_>, path: &[Ident]) -> Vec<Ident>{
     let mut visible_path = vec![];
     match cx.toplevel_reexport {
         Some(id) => visible_path.push(id),
diff --git a/src/libsyntax/test_snippet.rs b/src/libsyntax/test_snippet.rs
index 26b4762aaf37e..cf39090e1888b 100644
--- a/src/libsyntax/test_snippet.rs
+++ b/src/libsyntax/test_snippet.rs
@@ -1,6 +1,9 @@
-use source_map::{SourceMap, FilePathMapping};
+use crate::source_map::{SourceMap, FilePathMapping};
+use crate::with_globals;
+
 use errors::Handler;
 use errors::emitter::EmitterWriter;
+
 use std::io;
 use std::io::prelude::*;
 use rustc_data_structures::sync::Lrc;
@@ -8,7 +11,6 @@ use std::str;
 use std::sync::{Arc, Mutex};
 use std::path::Path;
 use syntax_pos::{BytePos, NO_EXPANSION, Span, MultiSpan};
-use with_globals;
 
 /// Identify a position in the text by the Nth occurrence of a string.
 struct Position {
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index fb72ef9c956ce..c4f2cffb09708 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -5,6 +5,7 @@
 //! which are themselves a single `Token` or a `Delimited` subsequence of tokens.
 //!
 //! ## Ownership
+//!
 //! `TokenStreams` are persistent data structures constructed as ropes with reference
 //! counted-children. In general, this means that calling an operation on a `TokenStream`
 //! (such as `slice`) produces an entirely new `TokenStream` from the borrowed reference to
@@ -12,12 +13,15 @@
 //! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
 //! ownership of the original.
 
+use crate::ext::base;
+use crate::ext::tt::{macro_parser, quoted};
+use crate::parse::Directory;
+use crate::parse::token::{self, DelimToken, Token};
+use crate::print::pprust;
+
 use syntax_pos::{BytePos, Mark, Span, DUMMY_SP};
-use ext::base;
-use ext::tt::{macro_parser, quoted};
-use parse::Directory;
-use parse::token::{self, DelimToken, Token};
-use print::pprust;
+#[cfg(target_arch = "x86_64")]
+use rustc_data_structures::static_assert;
 use rustc_data_structures::sync::Lrc;
 use serialize::{Decoder, Decodable, Encoder, Encodable};
 
@@ -41,12 +45,12 @@ pub enum TokenTree {
     /// A single token
     Token(Span, token::Token),
     /// A delimited sequence of token trees
-    Delimited(DelimSpan, DelimToken, ThinTokenStream),
+    Delimited(DelimSpan, DelimToken, TokenStream),
 }
 
 impl TokenTree {
     /// Use this token tree as a matcher to parse given tts.
-    pub fn parse(cx: &base::ExtCtxt, mtch: &[quoted::TokenTree], tts: TokenStream)
+    pub fn parse(cx: &base::ExtCtxt<'_>, mtch: &[quoted::TokenTree], tts: TokenStream)
                  -> macro_parser::NamedParseResult {
         // `None` is because we're not interpolating
         let directory = Directory {
@@ -56,14 +60,13 @@ impl TokenTree {
         macro_parser::parse(cx.parse_sess(), tts, mtch, Some(directory), true)
     }
 
-    /// Check if this TokenTree is equal to the other, regardless of span information.
+    /// Checks if this TokenTree is equal to the other, regardless of span information.
     pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
         match (self, other) {
             (&TokenTree::Token(_, ref tk), &TokenTree::Token(_, ref tk2)) => tk == tk2,
             (&TokenTree::Delimited(_, delim, ref tts),
              &TokenTree::Delimited(_, delim2, ref tts2)) => {
-                delim == delim2 &&
-                tts.stream().eq_unspanned(&tts2.stream())
+                delim == delim2 && tts.eq_unspanned(&tts2)
             }
             (_, _) => false,
         }
@@ -81,14 +84,13 @@ impl TokenTree {
             }
             (&TokenTree::Delimited(_, delim, ref tts),
              &TokenTree::Delimited(_, delim2, ref tts2)) => {
-                delim == delim2 &&
-                tts.stream().probably_equal_for_proc_macro(&tts2.stream())
+                delim == delim2 && tts.probably_equal_for_proc_macro(&tts2)
             }
             (_, _) => false,
         }
     }
 
-    /// Retrieve the TokenTree's span.
+    /// Retrieves the TokenTree's span.
     pub fn span(&self) -> Span {
         match *self {
             TokenTree::Token(sp, _) => sp,
@@ -113,7 +115,7 @@ impl TokenTree {
     }
 
     pub fn joint(self) -> TokenStream {
-        TokenStream::Tree(self, Joint)
+        TokenStream::new(vec![(self, Joint)])
     }
 
     /// Returns the opening delimiter as a token tree.
@@ -143,18 +145,19 @@ impl TokenTree {
 /// The goal is for procedural macros to work with `TokenStream`s and `TokenTree`s
 /// instead of a representation of the abstract syntax tree.
 /// Today's `TokenTree`s can still contain AST via `Token::Interpolated` for back-compat.
+///
+/// The use of `Option` is an optimization that avoids the need for an
+/// allocation when the stream is empty. However, it is not guaranteed that an
+/// empty stream is represented with `None`; it may be represented as a `Some`
+/// around an empty `Vec`.
 #[derive(Clone, Debug)]
-pub enum TokenStream {
-    Empty,
-    Tree(TokenTree, IsJoint),
-    Stream(Lrc<Vec<TreeAndJoint>>),
-}
+pub struct TokenStream(pub Option<Lrc<Vec<TreeAndJoint>>>);
 
 pub type TreeAndJoint = (TokenTree, IsJoint);
 
 // `TokenStream` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(target_arch = "x86_64")]
-static_assert!(MEM_SIZE_OF_TOKEN_STREAM: mem::size_of::<TokenStream>() == 32);
+static_assert!(MEM_SIZE_OF_TOKEN_STREAM: mem::size_of::<TokenStream>() == 8);
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum IsJoint {
@@ -162,14 +165,14 @@ pub enum IsJoint {
     NonJoint
 }
 
-use self::IsJoint::*;
+use IsJoint::*;
 
 impl TokenStream {
     /// Given a `TokenStream` with a `Stream` of only two arguments, return a new `TokenStream`
     /// separating the two arguments with a comma for diagnostic suggestions.
     pub(crate) fn add_comma(&self) -> Option<(TokenStream, Span)> {
         // Used to suggest if a user writes `foo!(a b);`
-        if let TokenStream::Stream(ref stream) = self {
+        if let Some(ref stream) = self.0 {
             let mut suggestion = None;
             let mut iter = stream.iter().enumerate().peekable();
             while let Some((pos, ts)) = iter.next() {
@@ -201,7 +204,7 @@ impl TokenStream {
 
 impl From<TokenTree> for TokenStream {
     fn from(tree: TokenTree) -> TokenStream {
-        TokenStream::Tree(tree, NonJoint)
+        TokenStream::new(vec![(tree, NonJoint)])
     }
 }
 
@@ -233,7 +236,7 @@ impl PartialEq<TokenStream> for TokenStream {
 
 impl TokenStream {
     pub fn len(&self) -> usize {
-        if let TokenStream::Stream(ref slice) = self {
+        if let Some(ref slice) = self.0 {
             slice.len()
         } else {
             0
@@ -241,13 +244,13 @@ impl TokenStream {
     }
 
     pub fn empty() -> TokenStream {
-        TokenStream::Empty
+        TokenStream(None)
     }
 
     pub fn is_empty(&self) -> bool {
-        match self {
-            TokenStream::Empty => true,
-            _ => false,
+        match self.0 {
+            None => true,
+            Some(ref stream) => stream.is_empty(),
         }
     }
 
@@ -256,12 +259,17 @@ impl TokenStream {
             0 => TokenStream::empty(),
             1 => streams.pop().unwrap(),
             _ => {
-                let mut vec = vec![];
+                // rust-lang/rust#57735: pre-allocate vector to avoid
+                // quadratic blow-up due to on-the-fly reallocations.
+                let tree_count = streams.iter()
+                    .map(|ts| match &ts.0 { None => 0, Some(s) => s.len() })
+                    .sum();
+                let mut vec = Vec::with_capacity(tree_count);
+
                 for stream in streams {
-                    match stream {
-                        TokenStream::Empty => {},
-                        TokenStream::Tree(tree, is_joint) => vec.push((tree, is_joint)),
-                        TokenStream::Stream(stream2) => vec.extend(stream2.iter().cloned()),
+                    match stream.0 {
+                        None => {},
+                        Some(stream2) => vec.extend(stream2.iter().cloned()),
                     }
                 }
                 TokenStream::new(vec)
@@ -269,22 +277,16 @@ impl TokenStream {
         }
     }
 
-    pub fn new(mut streams: Vec<TreeAndJoint>) -> TokenStream {
+    pub fn new(streams: Vec<TreeAndJoint>) -> TokenStream {
         match streams.len() {
-            0 => TokenStream::empty(),
-            1 => {
-                let (tree, is_joint) = streams.pop().unwrap();
-                TokenStream::Tree(tree, is_joint)
-            }
-            _ => TokenStream::Stream(Lrc::new(streams)),
+            0 => TokenStream(None),
+            _ => TokenStream(Some(Lrc::new(streams))),
         }
     }
 
     pub fn append_to_tree_and_joint_vec(self, vec: &mut Vec<TreeAndJoint>) {
-        match self {
-            TokenStream::Empty => {}
-            TokenStream::Tree(tree, is_joint) => vec.push((tree, is_joint)),
-            TokenStream::Stream(stream) => vec.extend(stream.iter().cloned()),
+        if let Some(stream) = self.0 {
+            vec.extend(stream.iter().cloned());
         }
     }
 
@@ -349,51 +351,36 @@ impl TokenStream {
     }
 
     pub fn map_enumerated<F: FnMut(usize, TokenTree) -> TokenTree>(self, mut f: F) -> TokenStream {
-        match self {
-            TokenStream::Empty => TokenStream::Empty,
-            TokenStream::Tree(tree, is_joint) => TokenStream::Tree(f(0, tree), is_joint),
-            TokenStream::Stream(stream) => TokenStream::Stream(Lrc::new(
+        TokenStream(self.0.map(|stream| {
+            Lrc::new(
                 stream
                     .iter()
                     .enumerate()
                     .map(|(i, (tree, is_joint))| (f(i, tree.clone()), *is_joint))
-                    .collect()
-            )),
-        }
+                    .collect())
+        }))
     }
 
     pub fn map<F: FnMut(TokenTree) -> TokenTree>(self, mut f: F) -> TokenStream {
-        match self {
-            TokenStream::Empty => TokenStream::Empty,
-            TokenStream::Tree(tree, is_joint) => TokenStream::Tree(f(tree), is_joint),
-            TokenStream::Stream(stream) => TokenStream::Stream(Lrc::new(
+        TokenStream(self.0.map(|stream| {
+            Lrc::new(
                 stream
                     .iter()
                     .map(|(tree, is_joint)| (f(tree.clone()), *is_joint))
-                    .collect()
-            )),
-        }
+                    .collect())
+        }))
     }
 
-    fn first_tree_and_joint(&self) -> Option<(TokenTree, IsJoint)> {
-        match self {
-            TokenStream::Empty => None,
-            TokenStream::Tree(ref tree, is_joint) => Some((tree.clone(), *is_joint)),
-            TokenStream::Stream(ref stream) => Some(stream.first().unwrap().clone())
-        }
+    fn first_tree_and_joint(&self) -> Option<TreeAndJoint> {
+        self.0.as_ref().map(|stream| {
+            stream.first().unwrap().clone()
+        })
     }
 
     fn last_tree_if_joint(&self) -> Option<TokenTree> {
-        match self {
-            TokenStream::Empty => None,
-            TokenStream::Tree(ref tree, is_joint) => {
-                if *is_joint == Joint {
-                    Some(tree.clone())
-                } else {
-                    None
-                }
-            }
-            TokenStream::Stream(ref stream) => {
+        match self.0 {
+            None => None,
+            Some(ref stream) => {
                 if let (tree, Joint) = stream.last().unwrap() {
                     Some(tree.clone())
                 } else {
@@ -422,7 +409,7 @@ impl TokenStreamBuilder {
                     self.push_all_but_last_tree(&last_stream);
                     let glued_span = last_span.to(span);
                     let glued_tt = TokenTree::Token(glued_span, glued_tok);
-                    let glued_tokenstream = TokenStream::Tree(glued_tt, is_joint);
+                    let glued_tokenstream = TokenStream::new(vec![(glued_tt, is_joint)]);
                     self.0.push(glued_tokenstream);
                     self.push_all_but_first_tree(&stream);
                     return
@@ -437,23 +424,21 @@ impl TokenStreamBuilder {
     }
 
     fn push_all_but_last_tree(&mut self, stream: &TokenStream) {
-        if let TokenStream::Stream(ref streams) = stream {
+        if let Some(ref streams) = stream.0 {
             let len = streams.len();
             match len {
                 1 => {}
-                2 => self.0.push(TokenStream::Tree(streams[0].0.clone(), streams[0].1)),
-                _ => self.0.push(TokenStream::Stream(Lrc::new(streams[0 .. len - 1].to_vec()))),
+                _ => self.0.push(TokenStream(Some(Lrc::new(streams[0 .. len - 1].to_vec())))),
             }
         }
     }
 
     fn push_all_but_first_tree(&mut self, stream: &TokenStream) {
-        if let TokenStream::Stream(ref streams) = stream {
+        if let Some(ref streams) = stream.0 {
             let len = streams.len();
             match len {
                 1 => {}
-                2 => self.0.push(TokenStream::Tree(streams[1].0.clone(), streams[1].1)),
-                _ => self.0.push(TokenStream::Stream(Lrc::new(streams[1 .. len].to_vec()))),
+                _ => self.0.push(TokenStream(Some(Lrc::new(streams[1 .. len].to_vec())))),
             }
         }
     }
@@ -479,17 +464,9 @@ impl Cursor {
     }
 
     pub fn next_with_joint(&mut self) -> Option<TreeAndJoint> {
-        match self.stream {
-            TokenStream::Empty => None,
-            TokenStream::Tree(ref tree, ref is_joint) => {
-                if self.index == 0 {
-                    self.index = 1;
-                    Some((tree.clone(), *is_joint))
-                } else {
-                    None
-                }
-            }
-            TokenStream::Stream(ref stream) => {
+        match self.stream.0 {
+            None => None,
+            Some(ref stream) => {
                 if self.index < stream.len() {
                     self.index += 1;
                     Some(stream[self.index - 1].clone())
@@ -505,65 +482,21 @@ impl Cursor {
             return;
         }
         let index = self.index;
-        let stream = mem::replace(&mut self.stream, TokenStream::Empty);
+        let stream = mem::replace(&mut self.stream, TokenStream(None));
         *self = TokenStream::from_streams(vec![stream, new_stream]).into_trees();
         self.index = index;
     }
 
     pub fn look_ahead(&self, n: usize) -> Option<TokenTree> {
-        match self.stream {
-            TokenStream::Empty => None,
-            TokenStream::Tree(ref tree, _) => {
-                if n == 0 && self.index == 0 {
-                    Some(tree.clone())
-                } else {
-                    None
-                }
-            }
-            TokenStream::Stream(ref stream) =>
-                stream[self.index ..].get(n).map(|(tree, _)| tree.clone()),
+        match self.stream.0 {
+            None => None,
+            Some(ref stream) => stream[self.index ..].get(n).map(|(tree, _)| tree.clone()),
         }
     }
 }
 
-/// The `TokenStream` type is large enough to represent a single `TokenTree` without allocation.
-/// `ThinTokenStream` is smaller, but needs to allocate to represent a single `TokenTree`.
-/// We must use `ThinTokenStream` in `TokenTree::Delimited` to avoid infinite size due to recursion.
-#[derive(Debug, Clone)]
-pub struct ThinTokenStream(Option<Lrc<Vec<TreeAndJoint>>>);
-
-impl ThinTokenStream {
-    pub fn stream(&self) -> TokenStream {
-        self.clone().into()
-    }
-}
-
-impl From<TokenStream> for ThinTokenStream {
-    fn from(stream: TokenStream) -> ThinTokenStream {
-        ThinTokenStream(match stream {
-            TokenStream::Empty => None,
-            TokenStream::Tree(tree, is_joint) => Some(Lrc::new(vec![(tree, is_joint)])),
-            TokenStream::Stream(stream) => Some(stream),
-        })
-    }
-}
-
-impl From<ThinTokenStream> for TokenStream {
-    fn from(stream: ThinTokenStream) -> TokenStream {
-        stream.0.map(TokenStream::Stream).unwrap_or_else(TokenStream::empty)
-    }
-}
-
-impl Eq for ThinTokenStream {}
-
-impl PartialEq<ThinTokenStream> for ThinTokenStream {
-    fn eq(&self, other: &ThinTokenStream) -> bool {
-        TokenStream::from(self.clone()) == TokenStream::from(other.clone())
-    }
-}
-
 impl fmt::Display for TokenStream {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(&pprust::tokens_to_string(self.clone()))
     }
 }
@@ -580,18 +513,6 @@ impl Decodable for TokenStream {
     }
 }
 
-impl Encodable for ThinTokenStream {
-    fn encode<E: Encoder>(&self, encoder: &mut E) -> Result<(), E::Error> {
-        TokenStream::from(self.clone()).encode(encoder)
-    }
-}
-
-impl Decodable for ThinTokenStream {
-    fn decode<D: Decoder>(decoder: &mut D) -> Result<ThinTokenStream, D::Error> {
-        TokenStream::decode(decoder).map(Into::into)
-    }
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, RustcEncodable, RustcDecodable)]
 pub struct DelimSpan {
     pub open: Span,
@@ -629,11 +550,11 @@ impl DelimSpan {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use syntax::ast::Ident;
-    use with_globals;
+    use crate::syntax::ast::Ident;
+    use crate::with_globals;
+    use crate::parse::token::Token;
+    use crate::util::parser_testing::string_to_stream;
     use syntax_pos::{Span, BytePos, NO_EXPANSION};
-    use parse::token::Token;
-    use util::parser_testing::string_to_stream;
 
     fn string_to_ts(string: &str) -> TokenStream {
         string_to_stream(string.to_owned())
diff --git a/src/libsyntax/util/lev_distance.rs b/src/libsyntax/util/lev_distance.rs
index d6d2251b5bc86..2f150d22159fa 100644
--- a/src/libsyntax/util/lev_distance.rs
+++ b/src/libsyntax/util/lev_distance.rs
@@ -1,7 +1,7 @@
 use std::cmp;
-use symbol::Symbol;
+use crate::symbol::Symbol;
 
-/// Find the Levenshtein distance between two strings
+/// Finds the Levenshtein distance between two strings
 pub fn lev_distance(a: &str, b: &str) -> usize {
     // cases which don't require further computation
     if a.is_empty() {
@@ -32,7 +32,7 @@ pub fn lev_distance(a: &str, b: &str) -> usize {
     dcol[t_last + 1]
 }
 
-/// Find the best match for a given word in the given iterator
+/// Finds the best match for a given word in the given iterator
 ///
 /// As a loose rule to avoid the obviously incorrect suggestions, it takes
 /// an optional limit for the maximum allowable edit distance, which defaults
@@ -101,7 +101,7 @@ fn test_lev_distance() {
 
 #[test]
 fn test_find_best_match_for_name() {
-    use with_globals;
+    use crate::with_globals;
     with_globals(|| {
         let input = vec![Symbol::intern("aaab"), Symbol::intern("aaabc")];
         assert_eq!(
diff --git a/src/libsyntax/util/move_map.rs b/src/libsyntax/util/map_in_place.rs
similarity index 82%
rename from src/libsyntax/util/move_map.rs
rename to src/libsyntax/util/map_in_place.rs
index a0f9d39ce89b3..5724b540a0dcf 100644
--- a/src/libsyntax/util/move_map.rs
+++ b/src/libsyntax/util/map_in_place.rs
@@ -1,18 +1,18 @@
 use std::ptr;
 use smallvec::{Array, SmallVec};
 
-pub trait MoveMap<T>: Sized {
-    fn move_map<F>(self, mut f: F) -> Self where F: FnMut(T) -> T {
-        self.move_flat_map(|e| Some(f(e)))
+pub trait MapInPlace<T>: Sized {
+    fn map_in_place<F>(&mut self, mut f: F) where F: FnMut(T) -> T {
+        self.flat_map_in_place(|e| Some(f(e)))
     }
 
-    fn move_flat_map<F, I>(self, f: F) -> Self
+    fn flat_map_in_place<F, I>(&mut self, f: F)
         where F: FnMut(T) -> I,
               I: IntoIterator<Item=T>;
 }
 
-impl<T> MoveMap<T> for Vec<T> {
-    fn move_flat_map<F, I>(mut self, mut f: F) -> Self
+impl<T> MapInPlace<T> for Vec<T> {
+    fn flat_map_in_place<F, I>(&mut self, mut f: F)
         where F: FnMut(T) -> I,
               I: IntoIterator<Item=T>
     {
@@ -53,22 +53,11 @@ impl<T> MoveMap<T> for Vec<T> {
             // write_i tracks the number of actually written new items.
             self.set_len(write_i);
         }
-
-        self
-    }
-}
-
-impl<T> MoveMap<T> for ::ptr::P<[T]> {
-    fn move_flat_map<F, I>(self, f: F) -> Self
-        where F: FnMut(T) -> I,
-              I: IntoIterator<Item=T>
-    {
-        ::ptr::P::from_vec(self.into_vec().move_flat_map(f))
     }
 }
 
-impl<T, A: Array<Item = T>> MoveMap<T> for SmallVec<A> {
-    fn move_flat_map<F, I>(mut self, mut f: F) -> Self
+impl<T, A: Array<Item = T>> MapInPlace<T> for SmallVec<A> {
+    fn flat_map_in_place<F, I>(&mut self, mut f: F)
         where F: FnMut(T) -> I,
               I: IntoIterator<Item=T>
     {
@@ -109,7 +98,5 @@ impl<T, A: Array<Item = T>> MoveMap<T> for SmallVec<A> {
             // write_i tracks the number of actually written new items.
             self.set_len(write_i);
         }
-
-        self
     }
 }
diff --git a/src/libsyntax/util/node_count.rs b/src/libsyntax/util/node_count.rs
index 7dd213ae38b9e..521edac8f5fc3 100644
--- a/src/libsyntax/util/node_count.rs
+++ b/src/libsyntax/util/node_count.rs
@@ -1,7 +1,7 @@
 // Simply gives a rought count of the number of nodes in an AST.
 
-use visit::*;
-use ast::*;
+use crate::visit::*;
+use crate::ast::*;
 use syntax_pos::Span;
 
 pub struct NodeCounter {
@@ -69,7 +69,7 @@ impl<'ast> Visitor<'ast> for NodeCounter {
         self.count += 1;
         walk_generics(self, g)
     }
-    fn visit_fn(&mut self, fk: FnKind, fd: &FnDecl, s: Span, _: NodeId) {
+    fn visit_fn(&mut self, fk: FnKind<'_>, fd: &FnDecl, s: Span, _: NodeId) {
         self.count += 1;
         walk_fn(self, fk, fd, s)
     }
diff --git a/src/libsyntax/util/parser.rs b/src/libsyntax/util/parser.rs
index 89d4e53b8d140..5f15ede7b0b6a 100644
--- a/src/libsyntax/util/parser.rs
+++ b/src/libsyntax/util/parser.rs
@@ -1,6 +1,6 @@
-use parse::token::{Token, BinOpToken};
-use symbol::keywords;
-use ast::{self, BinOpKind};
+use crate::parse::token::{Token, BinOpToken};
+use crate::symbol::keywords;
+use crate::ast::{self, BinOpKind};
 
 /// Associative operator with precedence.
 ///
@@ -70,9 +70,9 @@ pub enum Fixity {
 }
 
 impl AssocOp {
-    /// Create a new AssocOP from a token
+    /// Creates a new AssocOP from a token
     pub fn from_token(t: &Token) -> Option<AssocOp> {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match *t {
             Token::BinOpEq(k) => Some(AssignOp(k)),
             Token::LArrow => Some(ObsoleteInPlace),
@@ -105,9 +105,9 @@ impl AssocOp {
         }
     }
 
-    /// Create a new AssocOp from ast::BinOpKind.
+    /// Creates a new AssocOp from ast::BinOpKind.
     pub fn from_ast_binop(op: BinOpKind) -> Self {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match op {
             BinOpKind::Lt => Less,
             BinOpKind::Gt => Greater,
@@ -132,7 +132,7 @@ impl AssocOp {
 
     /// Gets the precedence of this operator
     pub fn precedence(&self) -> usize {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match *self {
             As | Colon => 14,
             Multiply | Divide | Modulus => 13,
@@ -152,7 +152,7 @@ impl AssocOp {
 
     /// Gets the fixity of this operator
     pub fn fixity(&self) -> Fixity {
-        use self::AssocOp::*;
+        use AssocOp::*;
         // NOTE: it is a bug to have an operators that has same precedence but different fixities!
         match *self {
             ObsoleteInPlace | Assign | AssignOp(_) => Fixity::Right,
@@ -164,7 +164,7 @@ impl AssocOp {
     }
 
     pub fn is_comparison(&self) -> bool {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match *self {
             Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual => true,
             ObsoleteInPlace | Assign | AssignOp(_) | As | Multiply | Divide | Modulus | Add |
@@ -174,7 +174,7 @@ impl AssocOp {
     }
 
     pub fn is_assign_like(&self) -> bool {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match *self {
             Assign | AssignOp(_) | ObsoleteInPlace => true,
             Less | Greater | LessEqual | GreaterEqual | Equal | NotEqual | As | Multiply | Divide |
@@ -184,7 +184,7 @@ impl AssocOp {
     }
 
     pub fn to_ast_binop(&self) -> Option<BinOpKind> {
-        use self::AssocOp::*;
+        use AssocOp::*;
         match *self {
             Less => Some(BinOpKind::Lt),
             Greater => Some(BinOpKind::Gt),
diff --git a/src/libsyntax/util/parser_testing.rs b/src/libsyntax/util/parser_testing.rs
index e407be6c1fe80..733c4f83e37d4 100644
--- a/src/libsyntax/util/parser_testing.rs
+++ b/src/libsyntax/util/parser_testing.rs
@@ -1,18 +1,22 @@
-use ast::{self, Ident};
-use source_map::FilePathMapping;
-use parse::{ParseSess, PResult, source_file_to_stream};
-use parse::{lexer, new_parser_from_source_str};
-use parse::parser::Parser;
-use ptr::P;
-use tokenstream::TokenStream;
+use crate::ast::{self, Ident};
+use crate::source_map::FilePathMapping;
+use crate::parse::{ParseSess, PResult, source_file_to_stream};
+use crate::parse::{lexer, new_parser_from_source_str};
+use crate::parse::parser::Parser;
+use crate::ptr::P;
+use crate::tokenstream::TokenStream;
+
 use std::iter::Peekable;
 use std::path::PathBuf;
 
 /// Map a string to tts, using a made-up filename:
 pub fn string_to_stream(source_str: String) -> TokenStream {
     let ps = ParseSess::new(FilePathMapping::empty());
-    source_file_to_stream(&ps, ps.source_map()
-                             .new_source_file(PathBuf::from("bogofile").into(), source_str), None)
+    source_file_to_stream(
+        &ps,
+        ps.source_map().new_source_file(PathBuf::from("bogofile").into(),
+        source_str,
+    ), None).0
 }
 
 /// Map string to parser (via tts)
@@ -25,7 +29,7 @@ fn with_error_checking_parse<'a, T, F>(s: String, ps: &'a ParseSess, f: F) -> T
 {
     let mut p = string_to_parser(&ps, s);
     let x = panictry!(f(&mut p));
-    p.abort_if_errors();
+    p.sess.span_diagnostic.abort_if_errors();
     x
 }
 
@@ -62,7 +66,7 @@ pub fn string_to_pat(source_str: String) -> P<ast::Pat> {
     })
 }
 
-/// Convert a vector of strings to a vector of Ident's
+/// Converts a vector of strings to a vector of Ident's
 pub fn strs_to_idents(ids: Vec<&str> ) -> Vec<Ident> {
     ids.iter().map(|u| Ident::from_str(*u)).collect()
 }
diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 156546bbba94a..a002394c710fe 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -6,17 +6,18 @@
 //! Note: it is an important invariant that the default visitor walks the body
 //! of a function in "execution order" (more concretely, reverse post-order
 //! with respect to the CFG implied by the AST), meaning that if AST node A may
-//! execute before AST node B, then A is visited first.  The borrow checker in
+//! execute before AST node B, then A is visited first. The borrow checker in
 //! particular relies on this property.
 //!
 //! Note: walking an AST before macro expansion is probably a bad idea. For
 //! instance, a walker looking for item names in a module will miss all of
 //! those that are created by the expansion of a macro.
 
-use ast::*;
+use crate::ast::*;
+use crate::parse::token::Token;
+use crate::tokenstream::{TokenTree, TokenStream};
+
 use syntax_pos::Span;
-use parse::token::Token;
-use tokenstream::{TokenTree, TokenStream};
 
 #[derive(Copy, Clone)]
 pub enum FnKind<'a> {
@@ -31,12 +32,12 @@ pub enum FnKind<'a> {
 }
 
 /// Each method of the Visitor trait is a hook to be potentially
-/// overridden.  Each method's default implementation recursively visits
+/// overridden. Each method's default implementation recursively visits
 /// the substructure of the input via the corresponding `walk` method;
 /// e.g., the `visit_mod` method by default calls `visit::walk_mod`.
 ///
 /// If you want to ensure that your code handles every variant
-/// explicitly, you need to override each method.  (And you also need
+/// explicitly, you need to override each method. (And you also need
 /// to monitor future changes to `Visitor` in case a new method with a
 /// new default implementation gets introduced.)
 pub trait Visitor<'ast>: Sized {
@@ -125,6 +126,7 @@ pub trait Visitor<'ast>: Sized {
         match generic_arg {
             GenericArg::Lifetime(lt) => self.visit_lifetime(lt),
             GenericArg::Type(ty) => self.visit_ty(ty),
+            GenericArg::Const(ct) => self.visit_anon_const(ct),
         }
     }
     fn visit_assoc_type_binding(&mut self, type_binding: &'ast TypeBinding) {
@@ -485,6 +487,7 @@ pub fn walk_generic_param<'a, V: Visitor<'a>>(visitor: &mut V, param: &'a Generi
     match param.kind {
         GenericParamKind::Lifetime => {}
         GenericParamKind::Type { ref default } => walk_list!(visitor, visit_ty, default),
+        GenericParamKind::Const { ref ty, .. } => visitor.visit_ty(ty),
     }
 }
 
@@ -832,7 +835,7 @@ pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute)
 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
     match tt {
         TokenTree::Token(_, tok) => visitor.visit_token(tok),
-        TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts.stream()),
+        TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
     }
 }
 
diff --git a/src/libsyntax_ext/Cargo.toml b/src/libsyntax_ext/Cargo.toml
index 7ad08f75e8bdd..773f0948a8a10 100644
--- a/src/libsyntax_ext/Cargo.toml
+++ b/src/libsyntax_ext/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "syntax_ext"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "syntax_ext"
@@ -10,7 +11,7 @@ crate-type = ["dylib"]
 
 [dependencies]
 fmt_macros = { path = "../libfmt_macros" }
-rustc_errors = { path = "../librustc_errors" }
+errors = { path = "../librustc_errors", package = "rustc_errors" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/libsyntax_ext/asm.rs b/src/libsyntax_ext/asm.rs
index 41ee6e91b3dc9..8edd0e1ae3884 100644
--- a/src/libsyntax_ext/asm.rs
+++ b/src/libsyntax_ext/asm.rs
@@ -1,13 +1,13 @@
 // Inline assembly support.
 //
-use self::State::*;
+use State::*;
 
 use rustc_data_structures::thin_vec::ThinVec;
 
 use errors::DiagnosticBuilder;
+
 use syntax::ast;
-use syntax::ext::base;
-use syntax::ext::base::*;
+use syntax::ext::base::{self, *};
 use syntax::feature_gate;
 use syntax::parse::{self, token};
 use syntax::ptr::P;
@@ -15,6 +15,7 @@ use syntax::symbol::Symbol;
 use syntax::ast::AsmDialect;
 use syntax_pos::Span;
 use syntax::tokenstream;
+use syntax::{span_err, struct_span_err};
 
 enum State {
     Asm,
@@ -40,7 +41,7 @@ impl State {
 
 const OPTIONS: &[&str] = &["volatile", "alignstack", "intel"];
 
-pub fn expand_asm<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_asm<'cx>(cx: &'cx mut ExtCtxt<'_>,
                        sp: Span,
                        tts: &[tokenstream::TokenTree])
                        -> Box<dyn base::MacResult + 'cx> {
diff --git a/src/libsyntax_ext/assert.rs b/src/libsyntax_ext/assert.rs
index b27f495322a42..d2c397e0eccb5 100644
--- a/src/libsyntax_ext/assert.rs
+++ b/src/libsyntax_ext/assert.rs
@@ -1,4 +1,5 @@
 use errors::DiagnosticBuilder;
+
 use syntax::ast::{self, *};
 use syntax::source_map::Spanned;
 use syntax::ext::base::*;
@@ -11,7 +12,7 @@ use syntax::tokenstream::{TokenStream, TokenTree};
 use syntax_pos::{Span, DUMMY_SP};
 
 pub fn expand_assert<'cx>(
-    cx: &'cx mut ExtCtxt,
+    cx: &'cx mut ExtCtxt<'_>,
     sp: Span,
     tts: &[TokenTree],
 ) -> Box<dyn MacResult + 'cx> {
diff --git a/src/libsyntax_ext/cfg.rs b/src/libsyntax_ext/cfg.rs
index 3b47b03cbe8dc..090d730289d26 100644
--- a/src/libsyntax_ext/cfg.rs
+++ b/src/libsyntax_ext/cfg.rs
@@ -3,16 +3,16 @@
 /// current compilation environment.
 
 use errors::DiagnosticBuilder;
+
 use syntax::ast;
-use syntax::ext::base::*;
-use syntax::ext::base;
+use syntax::ext::base::{self, *};
 use syntax::ext::build::AstBuilder;
 use syntax::attr;
 use syntax::tokenstream;
 use syntax::parse::token;
 use syntax_pos::Span;
 
-pub fn expand_cfg<'cx>(cx: &mut ExtCtxt,
+pub fn expand_cfg<'cx>(cx: &mut ExtCtxt<'_>,
                        sp: Span,
                        tts: &[tokenstream::TokenTree])
                        -> Box<dyn base::MacResult + 'static> {
diff --git a/src/libsyntax_ext/compile_error.rs b/src/libsyntax_ext/compile_error.rs
index 8f7f5deb091ac..59d3f2c9c7813 100644
--- a/src/libsyntax_ext/compile_error.rs
+++ b/src/libsyntax_ext/compile_error.rs
@@ -1,11 +1,10 @@
 // The compiler code necessary to support the compile_error! extension.
 
-use syntax::ext::base::*;
-use syntax::ext::base;
+use syntax::ext::base::{self, *};
 use syntax_pos::Span;
 use syntax::tokenstream;
 
-pub fn expand_compile_error<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_compile_error<'cx>(cx: &'cx mut ExtCtxt<'_>,
                               sp: Span,
                               tts: &[tokenstream::TokenTree])
                               -> Box<dyn base::MacResult + 'cx> {
diff --git a/src/libsyntax_ext/concat.rs b/src/libsyntax_ext/concat.rs
index 807f190cb6a1a..230b00c0f8f55 100644
--- a/src/libsyntax_ext/concat.rs
+++ b/src/libsyntax_ext/concat.rs
@@ -3,12 +3,11 @@ use syntax::ext::base;
 use syntax::ext::build::AstBuilder;
 use syntax::symbol::Symbol;
 use syntax::tokenstream;
-use syntax_pos;
 
 use std::string::String;
 
 pub fn expand_syntax_ext(
-    cx: &mut base::ExtCtxt,
+    cx: &mut base::ExtCtxt<'_>,
     sp: syntax_pos::Span,
     tts: &[tokenstream::TokenTree],
 ) -> Box<dyn base::MacResult + 'static> {
@@ -23,6 +22,7 @@ pub fn expand_syntax_ext(
         match e.node {
             ast::ExprKind::Lit(ref lit) => match lit.node {
                 ast::LitKind::Str(ref s, _)
+                | ast::LitKind::Err(ref s)
                 | ast::LitKind::Float(ref s, _)
                 | ast::LitKind::FloatUnsuffixed(ref s) => {
                     accumulator.push_str(&s.as_str());
diff --git a/src/libsyntax_ext/concat_idents.rs b/src/libsyntax_ext/concat_idents.rs
index de96de4bdc2bc..8c9eb4bf2d8ff 100644
--- a/src/libsyntax_ext/concat_idents.rs
+++ b/src/libsyntax_ext/concat_idents.rs
@@ -1,8 +1,7 @@
 use rustc_data_structures::thin_vec::ThinVec;
 
 use syntax::ast;
-use syntax::ext::base::*;
-use syntax::ext::base;
+use syntax::ext::base::{self, *};
 use syntax::feature_gate;
 use syntax::parse::token;
 use syntax::ptr::P;
@@ -10,7 +9,7 @@ use syntax_pos::Span;
 use syntax_pos::symbol::Symbol;
 use syntax::tokenstream::TokenTree;
 
-pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt<'_>,
                               sp: Span,
                               tts: &[TokenTree])
                               -> Box<dyn base::MacResult + 'cx> {
diff --git a/src/libsyntax_ext/deriving/bounds.rs b/src/libsyntax_ext/deriving/bounds.rs
index dcfc6ab0391b8..c7b805e0bdca6 100644
--- a/src/libsyntax_ext/deriving/bounds.rs
+++ b/src/libsyntax_ext/deriving/bounds.rs
@@ -1,11 +1,12 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
+
 use syntax::ast::MetaItem;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax_pos::Span;
 
-pub fn expand_deriving_unsafe_bound(cx: &mut ExtCtxt,
+pub fn expand_deriving_unsafe_bound(cx: &mut ExtCtxt<'_>,
                                     span: Span,
                                     _: &MetaItem,
                                     _: &Annotatable,
@@ -13,7 +14,7 @@ pub fn expand_deriving_unsafe_bound(cx: &mut ExtCtxt,
     cx.span_err(span, "this unsafe trait should be implemented explicitly");
 }
 
-pub fn expand_deriving_copy(cx: &mut ExtCtxt,
+pub fn expand_deriving_copy(cx: &mut ExtCtxt<'_>,
                             span: Span,
                             mitem: &MetaItem,
                             item: &Annotatable,
diff --git a/src/libsyntax_ext/deriving/clone.rs b/src/libsyntax_ext/deriving/clone.rs
index 38d433e842cd7..b347092e1bc4c 100644
--- a/src/libsyntax_ext/deriving/clone.rs
+++ b/src/libsyntax_ext/deriving/clone.rs
@@ -1,9 +1,8 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
-use syntax::ast::{self, Expr, Generics, ItemKind, MetaItem, VariantData};
-use syntax::ast::GenericArg;
+use syntax::ast::{self, Expr, GenericArg, Generics, ItemKind, MetaItem, VariantData};
 use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
@@ -11,7 +10,7 @@ use syntax::ptr::P;
 use syntax::symbol::{Symbol, keywords};
 use syntax_pos::Span;
 
-pub fn expand_deriving_clone(cx: &mut ExtCtxt,
+pub fn expand_deriving_clone(cx: &mut ExtCtxt<'_>,
                              span: Span,
                              mitem: &MetaItem,
                              item: &Annotatable,
@@ -105,12 +104,12 @@ pub fn expand_deriving_clone(cx: &mut ExtCtxt,
 }
 
 fn cs_clone_shallow(name: &str,
-                    cx: &mut ExtCtxt,
+                    cx: &mut ExtCtxt<'_>,
                     trait_span: Span,
-                    substr: &Substructure,
+                    substr: &Substructure<'_>,
                     is_union: bool)
                     -> P<Expr> {
-    fn assert_ty_bounds(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>,
+    fn assert_ty_bounds(cx: &mut ExtCtxt<'_>, stmts: &mut Vec<ast::Stmt>,
                         ty: P<ast::Ty>, span: Span, helper_name: &str) {
         // Generate statement `let _: helper_name<ty>;`,
         // set the expn ID so we can use the unstable struct.
@@ -120,7 +119,7 @@ fn cs_clone_shallow(name: &str,
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
-    fn process_variant(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>, variant: &VariantData) {
+    fn process_variant(cx: &mut ExtCtxt<'_>, stmts: &mut Vec<ast::Stmt>, variant: &VariantData) {
         for field in variant.fields() {
             // let _: AssertParamIsClone<FieldTy>;
             assert_ty_bounds(cx, stmts, field.ty.clone(), field.span, "AssertParamIsClone");
@@ -151,14 +150,14 @@ fn cs_clone_shallow(name: &str,
 }
 
 fn cs_clone(name: &str,
-            cx: &mut ExtCtxt,
+            cx: &mut ExtCtxt<'_>,
             trait_span: Span,
-            substr: &Substructure)
+            substr: &Substructure<'_>)
             -> P<Expr> {
     let ctor_path;
     let all_fields;
     let fn_path = cx.std_path(&["clone", "Clone", "clone"]);
-    let subcall = |cx: &mut ExtCtxt, field: &FieldInfo| {
+    let subcall = |cx: &mut ExtCtxt<'_>, field: &FieldInfo<'_>| {
         let args = vec![cx.expr_addr_of(field.span, field.self_.clone())];
         cx.expr_call_global(field.span, fn_path.clone(), args)
     };
diff --git a/src/libsyntax_ext/deriving/cmp/eq.rs b/src/libsyntax_ext/deriving/cmp/eq.rs
index dbba8c3b7a006..a1035ff641fa1 100644
--- a/src/libsyntax_ext/deriving/cmp/eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/eq.rs
@@ -1,6 +1,6 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{self, Expr, MetaItem, GenericArg};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -9,7 +9,7 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_eq(cx: &mut ExtCtxt,
+pub fn expand_deriving_eq(cx: &mut ExtCtxt<'_>,
                           span: Span,
                           mitem: &MetaItem,
                           item: &Annotatable,
@@ -44,8 +44,11 @@ pub fn expand_deriving_eq(cx: &mut ExtCtxt,
     trait_def.expand_ext(cx, mitem, item, push, true)
 }
 
-fn cs_total_eq_assert(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
-    fn assert_ty_bounds(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>,
+fn cs_total_eq_assert(cx: &mut ExtCtxt<'_>,
+                      trait_span: Span,
+                      substr: &Substructure<'_>)
+                      -> P<Expr> {
+    fn assert_ty_bounds(cx: &mut ExtCtxt<'_>, stmts: &mut Vec<ast::Stmt>,
                         ty: P<ast::Ty>, span: Span, helper_name: &str) {
         // Generate statement `let _: helper_name<ty>;`,
         // set the expn ID so we can use the unstable struct.
@@ -55,7 +58,9 @@ fn cs_total_eq_assert(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure)
                                         vec![GenericArg::Type(ty)], vec![]);
         stmts.push(cx.stmt_let_type_only(span, cx.ty_path(assert_path)));
     }
-    fn process_variant(cx: &mut ExtCtxt, stmts: &mut Vec<ast::Stmt>, variant: &ast::VariantData) {
+    fn process_variant(cx: &mut ExtCtxt<'_>,
+                       stmts: &mut Vec<ast::Stmt>,
+                       variant: &ast::VariantData) {
         for field in variant.fields() {
             // let _: AssertParamIsEq<FieldTy>;
             assert_ty_bounds(cx, stmts, field.ty.clone(), field.span, "AssertParamIsEq");
diff --git a/src/libsyntax_ext/deriving/cmp/ord.rs b/src/libsyntax_ext/deriving/cmp/ord.rs
index 21bd56710ac9b..e4f939c151f3e 100644
--- a/src/libsyntax_ext/deriving/cmp/ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/ord.rs
@@ -1,6 +1,6 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{self, Expr, MetaItem};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -9,7 +9,7 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_ord(cx: &mut ExtCtxt,
+pub fn expand_deriving_ord(cx: &mut ExtCtxt<'_>,
                            span: Span,
                            mitem: &MetaItem,
                            item: &Annotatable,
@@ -44,7 +44,7 @@ pub fn expand_deriving_ord(cx: &mut ExtCtxt,
 }
 
 
-pub fn ordering_collapsed(cx: &mut ExtCtxt,
+pub fn ordering_collapsed(cx: &mut ExtCtxt<'_>,
                           span: Span,
                           self_arg_tags: &[ast::Ident])
                           -> P<ast::Expr> {
@@ -53,7 +53,7 @@ pub fn ordering_collapsed(cx: &mut ExtCtxt,
     cx.expr_method_call(span, lft, cx.ident_of("cmp"), vec![rgt])
 }
 
-pub fn cs_cmp(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
+pub fn cs_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
     let equals_path = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
 
diff --git a/src/libsyntax_ext/deriving/cmp/partial_eq.rs b/src/libsyntax_ext/deriving/cmp/partial_eq.rs
index 4ec24bce4cd48..07026ae373919 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_eq.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_eq.rs
@@ -1,6 +1,6 @@
-use deriving::{path_local, path_std};
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::{path_local, path_std};
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{BinOpKind, Expr, MetaItem};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -9,22 +9,22 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt,
+pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt<'_>,
                                   span: Span,
                                   mitem: &MetaItem,
                                   item: &Annotatable,
                                   push: &mut dyn FnMut(Annotatable)) {
     // structures are equal if all fields are equal, and non equal, if
     // any fields are not equal or if the enum variants are different
-    fn cs_op(cx: &mut ExtCtxt,
+    fn cs_op(cx: &mut ExtCtxt<'_>,
              span: Span,
-             substr: &Substructure,
+             substr: &Substructure<'_>,
              op: BinOpKind,
              combiner: BinOpKind,
              base: bool)
              -> P<Expr>
     {
-        let op = |cx: &mut ExtCtxt, span: Span, self_f: P<Expr>, other_fs: &[P<Expr>]| {
+        let op = |cx: &mut ExtCtxt<'_>, span: Span, self_f: P<Expr>, other_fs: &[P<Expr>]| {
             let other_f = match (other_fs.len(), other_fs.get(0)) {
                 (1, Some(o_f)) => o_f,
                 _ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialEq)`"),
@@ -53,10 +53,10 @@ pub fn expand_deriving_partial_eq(cx: &mut ExtCtxt,
             substr)
     }
 
-    fn cs_eq(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
+    fn cs_eq(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
         cs_op(cx, span, substr, BinOpKind::Eq, BinOpKind::And, true)
     }
-    fn cs_ne(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
+    fn cs_ne(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
         cs_op(cx, span, substr, BinOpKind::Ne, BinOpKind::Or, false)
     }
 
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
index 9ef481edf51ca..e99abeb118ea2 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -1,8 +1,8 @@
-pub use self::OrderingOp::*;
+pub use OrderingOp::*;
 
-use deriving::{path_local, pathvec_std, path_std};
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::{path_local, pathvec_std, path_std};
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{self, BinOpKind, Expr, MetaItem};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -11,7 +11,7 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt,
+pub fn expand_deriving_partial_ord(cx: &mut ExtCtxt<'_>,
                                    span: Span,
                                    mitem: &MetaItem,
                                    item: &Annotatable,
@@ -95,7 +95,7 @@ pub enum OrderingOp {
     GeOp,
 }
 
-pub fn some_ordering_collapsed(cx: &mut ExtCtxt,
+pub fn some_ordering_collapsed(cx: &mut ExtCtxt<'_>,
                                span: Span,
                                op: OrderingOp,
                                self_arg_tags: &[ast::Ident])
@@ -112,7 +112,7 @@ pub fn some_ordering_collapsed(cx: &mut ExtCtxt,
     cx.expr_method_call(span, lft, cx.ident_of(op_str), vec![rgt])
 }
 
-pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
+pub fn cs_partial_cmp(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let test_id = cx.ident_of("cmp").gensym();
     let ordering = cx.path_global(span, cx.std_path(&["cmp", "Ordering", "Equal"]));
     let ordering_expr = cx.expr_path(ordering.clone());
@@ -184,14 +184,14 @@ pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<
 /// Strict inequality.
 fn cs_op(less: bool,
          inclusive: bool,
-         cx: &mut ExtCtxt,
+         cx: &mut ExtCtxt<'_>,
          span: Span,
-         substr: &Substructure) -> P<Expr> {
-    let ordering_path = |cx: &mut ExtCtxt, name: &str| {
+         substr: &Substructure<'_>) -> P<Expr> {
+    let ordering_path = |cx: &mut ExtCtxt<'_>, name: &str| {
         cx.expr_path(cx.path_global(span, cx.std_path(&["cmp", "Ordering", name])))
     };
 
-    let par_cmp = |cx: &mut ExtCtxt, span, self_f: P<Expr>, other_fs: &[P<Expr>], default| {
+    let par_cmp = |cx: &mut ExtCtxt<'_>, span, self_f: P<Expr>, other_fs: &[P<Expr>], default| {
         let other_f = match (other_fs.len(), other_fs.get(0)) {
             (1, Some(o_f)) => o_f,
             _ => cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`"),
diff --git a/src/libsyntax_ext/deriving/custom.rs b/src/libsyntax_ext/deriving/custom.rs
index 2f20814ef3efd..6aba4d83cd27c 100644
--- a/src/libsyntax_ext/deriving/custom.rs
+++ b/src/libsyntax_ext/deriving/custom.rs
@@ -1,3 +1,6 @@
+use crate::proc_macro_impl::EXEC_STRATEGY;
+use crate::proc_macro_server;
+
 use errors::FatalError;
 use syntax::ast::{self, ItemKind, Attribute, Mac};
 use syntax::attr::{mark_used, mark_known};
@@ -9,8 +12,6 @@ use syntax::tokenstream;
 use syntax::visit::Visitor;
 use syntax_pos::DUMMY_SP;
 
-use proc_macro_impl::EXEC_STRATEGY;
-
 struct MarkAttrs<'a>(&'a [ast::Name]);
 
 impl<'a> Visitor<'a> for MarkAttrs<'a> {
@@ -25,15 +26,15 @@ impl<'a> Visitor<'a> for MarkAttrs<'a> {
 }
 
 pub struct ProcMacroDerive {
-    pub client: ::proc_macro::bridge::client::Client<
-        fn(::proc_macro::TokenStream) -> ::proc_macro::TokenStream,
+    pub client: proc_macro::bridge::client::Client<
+        fn(proc_macro::TokenStream) -> proc_macro::TokenStream,
     >,
     pub attrs: Vec<ast::Name>,
 }
 
 impl MultiItemModifier for ProcMacroDerive {
     fn expand(&self,
-              ecx: &mut ExtCtxt,
+              ecx: &mut ExtCtxt<'_>,
               span: Span,
               _meta_item: &ast::MetaItem,
               item: Annotatable)
@@ -67,7 +68,7 @@ impl MultiItemModifier for ProcMacroDerive {
         let token = Token::interpolated(token::NtItem(item));
         let input = tokenstream::TokenTree::Token(DUMMY_SP, token).into();
 
-        let server = ::proc_macro_server::Rustc::new(ecx);
+        let server = proc_macro_server::Rustc::new(ecx);
         let stream = match self.client.run(&EXEC_STRATEGY, server, input) {
             Ok(stream) => stream,
             Err(e) => {
diff --git a/src/libsyntax_ext/deriving/debug.rs b/src/libsyntax_ext/deriving/debug.rs
index b3e5bd9283ef6..7dc2d007d73d6 100644
--- a/src/libsyntax_ext/deriving/debug.rs
+++ b/src/libsyntax_ext/deriving/debug.rs
@@ -1,6 +1,6 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use rustc_data_structures::thin_vec::ThinVec;
 
@@ -11,7 +11,7 @@ use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
 use syntax_pos::{DUMMY_SP, Span};
 
-pub fn expand_deriving_debug(cx: &mut ExtCtxt,
+pub fn expand_deriving_debug(cx: &mut ExtCtxt<'_>,
                              span: Span,
                              mitem: &MetaItem,
                              item: &Annotatable,
@@ -47,7 +47,7 @@ pub fn expand_deriving_debug(cx: &mut ExtCtxt,
 }
 
 /// We use the debug builders to do the heavy lifting here
-fn show_substructure(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
+fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> P<Expr> {
     // build fmt.debug_struct(<name>).field(<fieldname>, &<fieldval>)....build()
     // or fmt.debug_tuple(<name>).field(&<fieldval>)....build()
     // based on the "shape".
@@ -124,7 +124,7 @@ fn show_substructure(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<E
     cx.expr_block(block)
 }
 
-fn stmt_let_undescore(cx: &mut ExtCtxt, sp: Span, expr: P<ast::Expr>) -> ast::Stmt {
+fn stmt_let_undescore(cx: &mut ExtCtxt<'_>, sp: Span, expr: P<ast::Expr>) -> ast::Stmt {
     let local = P(ast::Local {
         pat: cx.pat_wild(sp),
         ty: None,
diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs
index 89c630e991530..d773f3ff7bcc5 100644
--- a/src/libsyntax_ext/deriving/decodable.rs
+++ b/src/libsyntax_ext/deriving/decodable.rs
@@ -1,9 +1,9 @@
 //! The compiler code necessary for `#[derive(Decodable)]`. See encodable.rs for more.
 
-use deriving::{self, pathvec_std};
-use deriving::generic::*;
-use deriving::generic::ty::*;
-use deriving::warn_if_deprecated;
+use crate::deriving::{self, pathvec_std};
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
+use crate::deriving::warn_if_deprecated;
 
 use syntax::ast;
 use syntax::ast::{Expr, MetaItem, Mutability};
@@ -13,7 +13,7 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_rustc_decodable(cx: &mut ExtCtxt,
+pub fn expand_deriving_rustc_decodable(cx: &mut ExtCtxt<'_>,
                                        span: Span,
                                        mitem: &MetaItem,
                                        item: &Annotatable,
@@ -21,7 +21,7 @@ pub fn expand_deriving_rustc_decodable(cx: &mut ExtCtxt,
     expand_deriving_decodable_imp(cx, span, mitem, item, push, "rustc_serialize")
 }
 
-pub fn expand_deriving_decodable(cx: &mut ExtCtxt,
+pub fn expand_deriving_decodable(cx: &mut ExtCtxt<'_>,
                                  span: Span,
                                  mitem: &MetaItem,
                                  item: &Annotatable,
@@ -30,7 +30,7 @@ pub fn expand_deriving_decodable(cx: &mut ExtCtxt,
     expand_deriving_decodable_imp(cx, span, mitem, item, push, "serialize")
 }
 
-fn expand_deriving_decodable_imp(cx: &mut ExtCtxt,
+fn expand_deriving_decodable_imp(cx: &mut ExtCtxt<'_>,
                                  span: Span,
                                  mitem: &MetaItem,
                                  item: &Annotatable,
@@ -79,9 +79,9 @@ fn expand_deriving_decodable_imp(cx: &mut ExtCtxt,
     trait_def.expand(cx, mitem, item, push)
 }
 
-fn decodable_substructure(cx: &mut ExtCtxt,
+fn decodable_substructure(cx: &mut ExtCtxt<'_>,
                           trait_span: Span,
-                          substr: &Substructure,
+                          substr: &Substructure<'_>,
                           krate: &str)
                           -> P<Expr> {
     let decoder = substr.nonself_args[0].clone();
@@ -165,16 +165,16 @@ fn decodable_substructure(cx: &mut ExtCtxt,
     };
 }
 
-/// Create a decoder for a single enum variant/struct:
+/// Creates a decoder for a single enum variant/struct:
 /// - `outer_pat_path` is the path to this enum variant/struct
 /// - `getarg` should retrieve the `usize`-th field with name `@str`.
-fn decode_static_fields<F>(cx: &mut ExtCtxt,
+fn decode_static_fields<F>(cx: &mut ExtCtxt<'_>,
                            trait_span: Span,
                            outer_pat_path: ast::Path,
                            fields: &StaticFields,
                            mut getarg: F)
                            -> P<Expr>
-    where F: FnMut(&mut ExtCtxt, Span, Symbol, usize) -> P<Expr>
+    where F: FnMut(&mut ExtCtxt<'_>, Span, Symbol, usize) -> P<Expr>
 {
     match *fields {
         Unnamed(ref fields, is_tuple) => {
diff --git a/src/libsyntax_ext/deriving/default.rs b/src/libsyntax_ext/deriving/default.rs
index 32d02bec7989b..6db0a29165a4a 100644
--- a/src/libsyntax_ext/deriving/default.rs
+++ b/src/libsyntax_ext/deriving/default.rs
@@ -1,15 +1,16 @@
-use deriving::path_std;
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::path_std;
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{Expr, MetaItem};
 use syntax::ext::base::{Annotatable, DummyResult, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
 use syntax::symbol::Symbol;
+use syntax::span_err;
 use syntax_pos::Span;
 
-pub fn expand_deriving_default(cx: &mut ExtCtxt,
+pub fn expand_deriving_default(cx: &mut ExtCtxt<'_>,
                                span: Span,
                                mitem: &MetaItem,
                                item: &Annotatable,
@@ -42,7 +43,10 @@ pub fn expand_deriving_default(cx: &mut ExtCtxt,
     trait_def.expand(cx, mitem, item, push)
 }
 
-fn default_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
+fn default_substructure(cx: &mut ExtCtxt<'_>,
+                        trait_span: Span,
+                        substr: &Substructure<'_>)
+                        -> P<Expr> {
     let default_ident = cx.std_path(&["default", "Default", "default"]);
     let default_call = |span| cx.expr_call_global(span, default_ident.clone(), Vec::new());
 
diff --git a/src/libsyntax_ext/deriving/encodable.rs b/src/libsyntax_ext/deriving/encodable.rs
index c8935874158a2..faaedba3e77dd 100644
--- a/src/libsyntax_ext/deriving/encodable.rs
+++ b/src/libsyntax_ext/deriving/encodable.rs
@@ -1,5 +1,5 @@
 //! The compiler code necessary to implement the `#[derive(Encodable)]`
-//! (and `Decodable`, in decodable.rs) extension.  The idea here is that
+//! (and `Decodable`, in `decodable.rs`) extension. The idea here is that
 //! type-defining items may be tagged with `#[derive(Encodable, Decodable)]`.
 //!
 //! For example, a type like:
@@ -37,7 +37,7 @@
 //! ```
 //!
 //! Other interesting scenarios are when the item has type parameters or
-//! references other non-built-in types.  A type definition like:
+//! references other non-built-in types. A type definition like:
 //!
 //! ```
 //! # #[derive(Encodable, Decodable)] struct Span;
@@ -82,10 +82,10 @@
 //! }
 //! ```
 
-use deriving::{self, pathvec_std};
-use deriving::generic::*;
-use deriving::generic::ty::*;
-use deriving::warn_if_deprecated;
+use crate::deriving::{self, pathvec_std};
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
+use crate::deriving::warn_if_deprecated;
 
 use syntax::ast::{Expr, ExprKind, MetaItem, Mutability};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -94,7 +94,7 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 
-pub fn expand_deriving_rustc_encodable(cx: &mut ExtCtxt,
+pub fn expand_deriving_rustc_encodable(cx: &mut ExtCtxt<'_>,
                                        span: Span,
                                        mitem: &MetaItem,
                                        item: &Annotatable,
@@ -102,7 +102,7 @@ pub fn expand_deriving_rustc_encodable(cx: &mut ExtCtxt,
     expand_deriving_encodable_imp(cx, span, mitem, item, push, "rustc_serialize")
 }
 
-pub fn expand_deriving_encodable(cx: &mut ExtCtxt,
+pub fn expand_deriving_encodable(cx: &mut ExtCtxt<'_>,
                                  span: Span,
                                  mitem: &MetaItem,
                                  item: &Annotatable,
@@ -111,7 +111,7 @@ pub fn expand_deriving_encodable(cx: &mut ExtCtxt,
     expand_deriving_encodable_imp(cx, span, mitem, item, push, "serialize")
 }
 
-fn expand_deriving_encodable_imp(cx: &mut ExtCtxt,
+fn expand_deriving_encodable_imp(cx: &mut ExtCtxt<'_>,
                                  span: Span,
                                  mitem: &MetaItem,
                                  item: &Annotatable,
@@ -162,9 +162,9 @@ fn expand_deriving_encodable_imp(cx: &mut ExtCtxt,
     trait_def.expand(cx, mitem, item, push)
 }
 
-fn encodable_substructure(cx: &mut ExtCtxt,
+fn encodable_substructure(cx: &mut ExtCtxt<'_>,
                           trait_span: Span,
-                          substr: &Substructure,
+                          substr: &Substructure<'_>,
                           krate: &'static str)
                           -> P<Expr> {
     let encoder = substr.nonself_args[0].clone();
diff --git a/src/libsyntax_ext/deriving/generic/mod.rs b/src/libsyntax_ext/deriving/generic/mod.rs
index 22643db501693..b8f96c5bc0ea9 100644
--- a/src/libsyntax_ext/deriving/generic/mod.rs
+++ b/src/libsyntax_ext/deriving/generic/mod.rs
@@ -174,8 +174,8 @@
 //!                 (<ident of C1>, <span of C1>, Named(vec![(<ident of x>, <span of x>)]))])
 //! ```
 
-pub use self::StaticFields::*;
-pub use self::SubstructureFields::*;
+pub use StaticFields::*;
+pub use SubstructureFields::*;
 
 use std::cell::RefCell;
 use std::iter;
@@ -189,15 +189,15 @@ use syntax::attr;
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ext::build::AstBuilder;
 use syntax::source_map::{self, respan};
-use syntax::util::move_map::MoveMap;
+use syntax::util::map_in_place::MapInPlace;
 use syntax::ptr::P;
 use syntax::symbol::{Symbol, keywords};
 use syntax::parse::ParseSess;
 use syntax_pos::{DUMMY_SP, Span};
 
-use self::ty::{LifetimeBounds, Path, Ptr, PtrTy, Self_, Ty};
+use ty::{LifetimeBounds, Path, Ptr, PtrTy, Self_, Ty};
 
-use deriving;
+use crate::deriving;
 
 pub mod ty;
 
@@ -243,7 +243,7 @@ pub struct MethodDef<'a> {
     /// Arguments other than the self argument
     pub args: Vec<(Ty<'a>, &'a str)>,
 
-    /// Return type
+    /// Returns type
     pub ret_ty: Ty<'a>,
 
     pub attributes: Vec<ast::Attribute>,
@@ -303,7 +303,7 @@ pub enum SubstructureFields<'a> {
     EnumMatching(usize, usize, &'a ast::Variant, Vec<FieldInfo<'a>>),
 
     /// Non-matching variants of the enum, but with all state hidden from
-    /// the consequent code.  The first component holds `Ident`s for all of
+    /// the consequent code. The first component holds `Ident`s for all of
     /// the `Self` arguments; the second component is a slice of all of the
     /// variants for the enum itself, and the third component is a list of
     /// `Ident`s bound to the variant index values for each of the actual
@@ -321,15 +321,15 @@ pub enum SubstructureFields<'a> {
 /// Combine the values of all the fields together. The last argument is
 /// all the fields of all the structures.
 pub type CombineSubstructureFunc<'a> =
-    Box<dyn FnMut(&mut ExtCtxt, Span, &Substructure) -> P<Expr> + 'a>;
+    Box<dyn FnMut(&mut ExtCtxt<'_>, Span, &Substructure<'_>) -> P<Expr> + 'a>;
 
-/// Deal with non-matching enum variants.  The tuple is a list of
+/// Deal with non-matching enum variants. The tuple is a list of
 /// identifiers (one for each `Self` argument, which could be any of the
 /// variants since they have been collapsed together) and the identifiers
-/// holding the variant index value for each of the `Self` arguments.  The
+/// holding the variant index value for each of the `Self` arguments. The
 /// last argument is all the non-`Self` args of the method being derived.
 pub type EnumNonMatchCollapsedFunc<'a> =
-    Box<dyn FnMut(&mut ExtCtxt, Span, (&[Ident], &[Ident]), &[P<Expr>]) -> P<Expr> + 'a>;
+    Box<dyn FnMut(&mut ExtCtxt<'_>, Span, (&[Ident], &[Ident]), &[P<Expr>]) -> P<Expr> + 'a>;
 
 pub fn combine_substructure<'a>(f: CombineSubstructureFunc<'a>)
                                 -> RefCell<CombineSubstructureFunc<'a>> {
@@ -342,7 +342,7 @@ pub fn combine_substructure<'a>(f: CombineSubstructureFunc<'a>)
 fn find_type_parameters(ty: &ast::Ty,
                         ty_param_names: &[ast::Name],
                         span: Span,
-                        cx: &ExtCtxt)
+                        cx: &ExtCtxt<'_>)
                         -> Vec<P<ast::Ty>> {
     use syntax::visit;
 
@@ -386,7 +386,7 @@ fn find_type_parameters(ty: &ast::Ty,
 
 impl<'a> TraitDef<'a> {
     pub fn expand(self,
-                  cx: &mut ExtCtxt,
+                  cx: &mut ExtCtxt<'_>,
                   mitem: &ast::MetaItem,
                   item: &'a Annotatable,
                   push: &mut dyn FnMut(Annotatable)) {
@@ -394,7 +394,7 @@ impl<'a> TraitDef<'a> {
     }
 
     pub fn expand_ext(self,
-                      cx: &mut ExtCtxt,
+                      cx: &mut ExtCtxt<'_>,
                       mitem: &ast::MetaItem,
                       item: &'a Annotatable,
                       push: &mut dyn FnMut(Annotatable),
@@ -497,7 +497,7 @@ impl<'a> TraitDef<'a> {
     /// create an impl like:
     ///
     /// ```ignore (only-for-syntax-highlight)
-    /// impl<'a, ..., 'z, A, B: DeclaredTrait, C, ...  Z> where
+    /// impl<'a, ..., 'z, A, B: DeclaredTrait, C, ... Z> where
     ///     C:                       WhereTrait,
     ///     A: DerivedTrait + B1 + ... + BN,
     ///     B: DerivedTrait + B1 + ... + BN,
@@ -513,7 +513,7 @@ impl<'a> TraitDef<'a> {
     /// where B1, ..., BN are the bounds given by `bounds_paths`.'. Z is a phantom type, and
     /// therefore does not get bound by the derived trait.
     fn create_derived_impl(&self,
-                           cx: &mut ExtCtxt,
+                           cx: &mut ExtCtxt<'_>,
                            type_ident: Ident,
                            generics: &Generics,
                            field_tys: Vec<P<ast::Ty>>,
@@ -560,6 +560,7 @@ impl<'a> TraitDef<'a> {
 
                 cx.typaram(self.span, param.ident, vec![], bounds, None)
             }
+            GenericParamKind::Const { .. } => param.clone(),
         }));
 
         // and similarly for where clauses
@@ -657,6 +658,9 @@ impl<'a> TraitDef<'a> {
             GenericParamKind::Type { .. } => {
                 GenericArg::Type(cx.ty_ident(self.span, param.ident))
             }
+            GenericParamKind::Const { .. } => {
+                GenericArg::Const(cx.const_ident(self.span, param.ident))
+            }
         }).collect();
 
         // Create the type of `self`.
@@ -696,7 +700,7 @@ impl<'a> TraitDef<'a> {
     }
 
     fn expand_struct_def(&self,
-                         cx: &mut ExtCtxt,
+                         cx: &mut ExtCtxt<'_>,
                          struct_def: &'a VariantData,
                          type_ident: Ident,
                          generics: &Generics,
@@ -746,7 +750,7 @@ impl<'a> TraitDef<'a> {
     }
 
     fn expand_enum_def(&self,
-                       cx: &mut ExtCtxt,
+                       cx: &mut ExtCtxt<'_>,
                        enum_def: &'a EnumDef,
                        type_attrs: &[ast::Attribute],
                        type_ident: Ident,
@@ -832,12 +836,12 @@ fn find_repr_type_name(sess: &ParseSess, type_attrs: &[ast::Attribute]) -> &'sta
 
 impl<'a> MethodDef<'a> {
     fn call_substructure_method(&self,
-                                cx: &mut ExtCtxt,
-                                trait_: &TraitDef,
+                                cx: &mut ExtCtxt<'_>,
+                                trait_: &TraitDef<'_>,
                                 type_ident: Ident,
                                 self_args: &[P<Expr>],
                                 nonself_args: &[P<Expr>],
-                                fields: &SubstructureFields)
+                                fields: &SubstructureFields<'_>)
                                 -> P<Expr> {
         let substructure = Substructure {
             type_ident,
@@ -847,13 +851,13 @@ impl<'a> MethodDef<'a> {
             fields,
         };
         let mut f = self.combine_substructure.borrow_mut();
-        let f: &mut CombineSubstructureFunc = &mut *f;
+        let f: &mut CombineSubstructureFunc<'_> = &mut *f;
         f(cx, trait_.span, &substructure)
     }
 
     fn get_ret_ty(&self,
-                  cx: &mut ExtCtxt,
-                  trait_: &TraitDef,
+                  cx: &mut ExtCtxt<'_>,
+                  trait_: &TraitDef<'_>,
                   generics: &Generics,
                   type_ident: Ident)
                   -> P<ast::Ty> {
@@ -866,8 +870,8 @@ impl<'a> MethodDef<'a> {
 
     fn split_self_nonself_args
         (&self,
-         cx: &mut ExtCtxt,
-         trait_: &TraitDef,
+         cx: &mut ExtCtxt<'_>,
+         trait_: &TraitDef<'_>,
          type_ident: Ident,
          generics: &Generics)
          -> (Option<ast::ExplicitSelf>, Vec<P<Expr>>, Vec<P<Expr>>, Vec<(Ident, P<ast::Ty>)>) {
@@ -912,8 +916,8 @@ impl<'a> MethodDef<'a> {
     }
 
     fn create_method(&self,
-                     cx: &mut ExtCtxt,
-                     trait_: &TraitDef,
+                     cx: &mut ExtCtxt<'_>,
+                     trait_: &TraitDef<'_>,
                      type_ident: Ident,
                      generics: &Generics,
                      abi: Abi,
@@ -1005,7 +1009,7 @@ impl<'a> MethodDef<'a> {
     /// }
     /// ```
     fn expand_struct_method_body<'b>(&self,
-                                     cx: &mut ExtCtxt,
+                                     cx: &mut ExtCtxt<'_>,
                                      trait_: &TraitDef<'b>,
                                      struct_def: &'b VariantData,
                                      type_ident: Ident,
@@ -1077,8 +1081,8 @@ impl<'a> MethodDef<'a> {
     }
 
     fn expand_static_struct_method_body(&self,
-                                        cx: &mut ExtCtxt,
-                                        trait_: &TraitDef,
+                                        cx: &mut ExtCtxt<'_>,
+                                        trait_: &TraitDef<'_>,
                                         struct_def: &VariantData,
                                         type_ident: Ident,
                                         self_args: &[P<Expr>],
@@ -1122,10 +1126,10 @@ impl<'a> MethodDef<'a> {
     ///
     /// (Of course `__self_vi` and `__arg_1_vi` are unused for
     /// `PartialEq`, and those subcomputations will hopefully be removed
-    /// as their results are unused.  The point of `__self_vi` and
+    /// as their results are unused. The point of `__self_vi` and
     /// `__arg_1_vi` is for `PartialOrd`; see #15503.)
     fn expand_enum_method_body<'b>(&self,
-                                   cx: &mut ExtCtxt,
+                                   cx: &mut ExtCtxt<'_>,
                                    trait_: &TraitDef<'b>,
                                    enum_def: &'b EnumDef,
                                    type_attrs: &[ast::Attribute],
@@ -1179,12 +1183,12 @@ impl<'a> MethodDef<'a> {
     /// }
     /// ```
     fn build_enum_match_tuple<'b>(&self,
-                                  cx: &mut ExtCtxt,
+                                  cx: &mut ExtCtxt<'_>,
                                   trait_: &TraitDef<'b>,
                                   enum_def: &'b EnumDef,
                                   type_attrs: &[ast::Attribute],
                                   type_ident: Ident,
-                                  self_args: Vec<P<Expr>>,
+                                  mut self_args: Vec<P<Expr>>,
                                   nonself_args: &[P<Expr>])
                                   -> P<Expr> {
         let sp = trait_.span;
@@ -1230,7 +1234,7 @@ impl<'a> MethodDef<'a> {
             .enumerate()
             .filter(|&(_, v)| !(self.unify_fieldless_variants && v.node.data.fields().is_empty()))
             .map(|(index, variant)| {
-                let mk_self_pat = |cx: &mut ExtCtxt, self_arg_name: &str| {
+                let mk_self_pat = |cx: &mut ExtCtxt<'_>, self_arg_name: &str| {
                     let (p, idents) = trait_.create_enum_variant_pattern(cx,
                                                      type_ident,
                                                      variant,
@@ -1296,7 +1300,7 @@ impl<'a> MethodDef<'a> {
                                     other: others,
                                     attrs,
                         }
-                    }).collect::<Vec<FieldInfo>>();
+                    }).collect::<Vec<FieldInfo<'_>>>();
 
                 // Now, for some given VariantK, we have built up
                 // expressions for referencing every field of every
@@ -1417,8 +1421,8 @@ impl<'a> MethodDef<'a> {
             // them when they are fed as r-values into a tuple
             // expression; here add a layer of borrowing, turning
             // `(*self, *__arg_0, ...)` into `(&*self, &*__arg_0, ...)`.
-            let borrowed_self_args = self_args.move_map(|self_arg| cx.expr_addr_of(sp, self_arg));
-            let match_arg = cx.expr(sp, ast::ExprKind::Tup(borrowed_self_args));
+            self_args.map_in_place(|self_arg| cx.expr_addr_of(sp, self_arg));
+            let match_arg = cx.expr(sp, ast::ExprKind::Tup(self_args));
 
             // Lastly we create an expression which branches on all discriminants being equal
             //  if discriminant_test {
@@ -1494,15 +1498,15 @@ impl<'a> MethodDef<'a> {
             // them when they are fed as r-values into a tuple
             // expression; here add a layer of borrowing, turning
             // `(*self, *__arg_0, ...)` into `(&*self, &*__arg_0, ...)`.
-            let borrowed_self_args = self_args.move_map(|self_arg| cx.expr_addr_of(sp, self_arg));
-            let match_arg = cx.expr(sp, ast::ExprKind::Tup(borrowed_self_args));
+            self_args.map_in_place(|self_arg| cx.expr_addr_of(sp, self_arg));
+            let match_arg = cx.expr(sp, ast::ExprKind::Tup(self_args));
             cx.expr_match(sp, match_arg, match_arms)
         }
     }
 
     fn expand_static_enum_method_body(&self,
-                                      cx: &mut ExtCtxt,
-                                      trait_: &TraitDef,
+                                      cx: &mut ExtCtxt<'_>,
+                                      trait_: &TraitDef<'_>,
                                       enum_def: &EnumDef,
                                       type_ident: Ident,
                                       self_args: &[P<Expr>],
@@ -1527,7 +1531,7 @@ impl<'a> MethodDef<'a> {
 
 // general helper methods.
 impl<'a> TraitDef<'a> {
-    fn summarise_struct(&self, cx: &mut ExtCtxt, struct_def: &VariantData) -> StaticFields {
+    fn summarise_struct(&self, cx: &mut ExtCtxt<'_>, struct_def: &VariantData) -> StaticFields {
         let mut named_idents = Vec::new();
         let mut just_spans = Vec::new();
         for field in struct_def.fields() {
@@ -1553,7 +1557,7 @@ impl<'a> TraitDef<'a> {
     }
 
     fn create_subpatterns(&self,
-                          cx: &mut ExtCtxt,
+                          cx: &mut ExtCtxt<'_>,
                           field_paths: Vec<ast::Ident>,
                           mutbl: ast::Mutability,
                           use_temporaries: bool)
@@ -1573,7 +1577,7 @@ impl<'a> TraitDef<'a> {
 
     fn create_struct_pattern
         (&self,
-         cx: &mut ExtCtxt,
+         cx: &mut ExtCtxt<'_>,
          struct_path: ast::Path,
          struct_def: &'a VariantData,
          prefix: &str,
@@ -1633,7 +1637,7 @@ impl<'a> TraitDef<'a> {
 
     fn create_enum_variant_pattern
         (&self,
-         cx: &mut ExtCtxt,
+         cx: &mut ExtCtxt<'_>,
          enum_ident: ast::Ident,
          variant: &'a ast::Variant,
          prefix: &str,
@@ -1652,10 +1656,10 @@ impl<'a> TraitDef<'a> {
 pub fn cs_fold_fields<'a, F>(use_foldl: bool,
                              mut f: F,
                              base: P<Expr>,
-                             cx: &mut ExtCtxt,
+                             cx: &mut ExtCtxt<'_>,
                              all_fields: &[FieldInfo<'a>])
                              -> P<Expr>
-    where F: FnMut(&mut ExtCtxt, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>
+    where F: FnMut(&mut ExtCtxt<'_>, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>
 {
     if use_foldl {
         all_fields.iter().fold(base, |old, field| {
@@ -1668,10 +1672,10 @@ pub fn cs_fold_fields<'a, F>(use_foldl: bool,
     }
 }
 
-pub fn cs_fold_enumnonmatch(mut enum_nonmatch_f: EnumNonMatchCollapsedFunc,
-                            cx: &mut ExtCtxt,
+pub fn cs_fold_enumnonmatch(mut enum_nonmatch_f: EnumNonMatchCollapsedFunc<'_>,
+                            cx: &mut ExtCtxt<'_>,
                             trait_span: Span,
-                            substructure: &Substructure)
+                            substructure: &Substructure<'_>)
                             -> P<Expr>
 {
     match *substructure.fields {
@@ -1685,7 +1689,7 @@ pub fn cs_fold_enumnonmatch(mut enum_nonmatch_f: EnumNonMatchCollapsedFunc,
     }
 }
 
-pub fn cs_fold_static(cx: &mut ExtCtxt,
+pub fn cs_fold_static(cx: &mut ExtCtxt<'_>,
                       trait_span: Span)
                       -> P<Expr>
 {
@@ -1697,12 +1701,12 @@ pub fn cs_fold_static(cx: &mut ExtCtxt,
 pub fn cs_fold<F>(use_foldl: bool,
                   f: F,
                   base: P<Expr>,
-                  enum_nonmatch_f: EnumNonMatchCollapsedFunc,
-                  cx: &mut ExtCtxt,
+                  enum_nonmatch_f: EnumNonMatchCollapsedFunc<'_>,
+                  cx: &mut ExtCtxt<'_>,
                   trait_span: Span,
-                  substructure: &Substructure)
+                  substructure: &Substructure<'_>)
                   -> P<Expr>
-    where F: FnMut(&mut ExtCtxt, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>
+    where F: FnMut(&mut ExtCtxt<'_>, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>
 {
     match *substructure.fields {
         EnumMatching(.., ref all_fields) |
@@ -1720,7 +1724,7 @@ pub fn cs_fold<F>(use_foldl: bool,
 
 /// Function to fold over fields, with three cases, to generate more efficient and concise code.
 /// When the `substructure` has grouped fields, there are two cases:
-/// Zero fields: call the base case function with None (like the usual base case of `cs_fold`).
+/// Zero fields: call the base case function with `None` (like the usual base case of `cs_fold`).
 /// One or more fields: call the base case function on the first value (which depends on
 /// `use_fold`), and use that as the base case. Then perform `cs_fold` on the remainder of the
 /// fields.
@@ -1730,13 +1734,13 @@ pub fn cs_fold<F>(use_foldl: bool,
 pub fn cs_fold1<F, B>(use_foldl: bool,
                       f: F,
                       mut b: B,
-                      enum_nonmatch_f: EnumNonMatchCollapsedFunc,
-                      cx: &mut ExtCtxt,
+                      enum_nonmatch_f: EnumNonMatchCollapsedFunc<'_>,
+                      cx: &mut ExtCtxt<'_>,
                       trait_span: Span,
-                      substructure: &Substructure)
+                      substructure: &Substructure<'_>)
                       -> P<Expr>
-    where F: FnMut(&mut ExtCtxt, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>,
-          B: FnMut(&mut ExtCtxt, Option<(Span, P<Expr>, &[P<Expr>])>) -> P<Expr>
+    where F: FnMut(&mut ExtCtxt<'_>, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>,
+          B: FnMut(&mut ExtCtxt<'_>, Option<(Span, P<Expr>, &[P<Expr>])>) -> P<Expr>
 {
     match *substructure.fields {
         EnumMatching(.., ref all_fields) |
@@ -1776,12 +1780,12 @@ pub fn cs_fold1<F, B>(use_foldl: bool,
 /// ```
 #[inline]
 pub fn cs_same_method<F>(f: F,
-                         mut enum_nonmatch_f: EnumNonMatchCollapsedFunc,
-                         cx: &mut ExtCtxt,
+                         mut enum_nonmatch_f: EnumNonMatchCollapsedFunc<'_>,
+                         cx: &mut ExtCtxt<'_>,
                          trait_span: Span,
-                         substructure: &Substructure)
+                         substructure: &Substructure<'_>)
                          -> P<Expr>
-    where F: FnOnce(&mut ExtCtxt, Span, Vec<P<Expr>>) -> P<Expr>
+    where F: FnOnce(&mut ExtCtxt<'_>, Span, Vec<P<Expr>>) -> P<Expr>
 {
     match *substructure.fields {
         EnumMatching(.., ref all_fields) |
@@ -1811,7 +1815,7 @@ pub fn cs_same_method<F>(f: F,
     }
 }
 
-/// Return true if the type has no value fields
+/// Returns `true` if the type has no value fields
 /// (for an enum, no variant has any fields)
 pub fn is_type_without_fields(item: &Annotatable) -> bool {
     if let Annotatable::Item(ref item) = *item {
diff --git a/src/libsyntax_ext/deriving/generic/ty.rs b/src/libsyntax_ext/deriving/generic/ty.rs
index 83ec99b3573b4..100ec0057ee02 100644
--- a/src/libsyntax_ext/deriving/generic/ty.rs
+++ b/src/libsyntax_ext/deriving/generic/ty.rs
@@ -1,11 +1,10 @@
 //! A mini version of ast::Ty, which is easier to use, and features an explicit `Self` type to use
 //! when specifying impls to be derived.
 
-pub use self::PtrTy::*;
-pub use self::Ty::*;
+pub use PtrTy::*;
+pub use Ty::*;
 
-use syntax::ast;
-use syntax::ast::{Expr, GenericParamKind, Generics, Ident, SelfKind, GenericArg};
+use syntax::ast::{self, Expr, GenericParamKind, Generics, Ident, SelfKind, GenericArg};
 use syntax::ext::base::ExtCtxt;
 use syntax::ext::build::AstBuilder;
 use syntax::source_map::{respan, DUMMY_SP};
@@ -60,7 +59,7 @@ impl<'a> Path<'a> {
     }
 
     pub fn to_ty(&self,
-                 cx: &ExtCtxt,
+                 cx: &ExtCtxt<'_>,
                  span: Span,
                  self_ty: Ident,
                  self_generics: &Generics)
@@ -68,7 +67,7 @@ impl<'a> Path<'a> {
         cx.ty_path(self.to_path(cx, span, self_ty, self_generics))
     }
     pub fn to_path(&self,
-                   cx: &ExtCtxt,
+                   cx: &ExtCtxt<'_>,
                    span: Span,
                    self_ty: Ident,
                    self_generics: &Generics)
@@ -95,7 +94,7 @@ impl<'a> Path<'a> {
     }
 }
 
-/// A type. Supports pointers, Self, and literals
+/// A type. Supports pointers, Self, and literals.
 #[derive(Clone)]
 pub enum Ty<'a> {
     Self_,
@@ -108,6 +107,13 @@ pub enum Ty<'a> {
     Tuple(Vec<Ty<'a>>),
 }
 
+/// A const expression. Supports literals and blocks.
+#[derive(Clone, Eq, PartialEq)]
+pub enum Const {
+    Literal,
+    Block,
+}
+
 pub fn borrowed_ptrty<'r>() -> PtrTy<'r> {
     Borrowed(None, ast::Mutability::Immutable)
 }
@@ -127,19 +133,19 @@ pub fn nil_ty<'r>() -> Ty<'r> {
     Tuple(Vec::new())
 }
 
-fn mk_lifetime(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Option<ast::Lifetime> {
+fn mk_lifetime(cx: &ExtCtxt<'_>, span: Span, lt: &Option<&str>) -> Option<ast::Lifetime> {
     lt.map(|s|
         cx.lifetime(span, Ident::from_str(s))
     )
 }
 
-fn mk_lifetimes(cx: &ExtCtxt, span: Span, lt: &Option<&str>) -> Vec<ast::Lifetime> {
+fn mk_lifetimes(cx: &ExtCtxt<'_>, span: Span, lt: &Option<&str>) -> Vec<ast::Lifetime> {
     mk_lifetime(cx, span, lt).into_iter().collect()
 }
 
 impl<'a> Ty<'a> {
     pub fn to_ty(&self,
-                 cx: &ExtCtxt,
+                 cx: &ExtCtxt<'_>,
                  span: Span,
                  self_ty: Ident,
                  self_generics: &Generics)
@@ -167,7 +173,7 @@ impl<'a> Ty<'a> {
     }
 
     pub fn to_path(&self,
-                   cx: &ExtCtxt,
+                   cx: &ExtCtxt<'_>,
                    span: Span,
                    self_ty: Ident,
                    generics: &Generics)
@@ -181,6 +187,9 @@ impl<'a> Ty<'a> {
                     GenericParamKind::Type { .. } => {
                         GenericArg::Type(cx.ty_ident(span, param.ident))
                     }
+                    GenericParamKind::Const { .. } => {
+                        GenericArg::Const(cx.const_ident(span, param.ident))
+                    }
                 }).collect();
 
                 cx.path_all(span, false, vec![self_ty], params, vec![])
@@ -193,11 +202,11 @@ impl<'a> Ty<'a> {
 }
 
 
-fn mk_ty_param(cx: &ExtCtxt,
+fn mk_ty_param(cx: &ExtCtxt<'_>,
                span: Span,
                name: &str,
                attrs: &[ast::Attribute],
-               bounds: &[Path],
+               bounds: &[Path<'_>],
                self_ident: Ident,
                self_generics: &Generics)
                -> ast::GenericParam {
@@ -237,7 +246,7 @@ impl<'a> LifetimeBounds<'a> {
         }
     }
     pub fn to_generics(&self,
-                       cx: &ExtCtxt,
+                       cx: &ExtCtxt<'_>,
                        span: Span,
                        self_ty: Ident,
                        self_generics: &Generics)
@@ -262,9 +271,9 @@ impl<'a> LifetimeBounds<'a> {
     }
 }
 
-pub fn get_explicit_self(cx: &ExtCtxt,
+pub fn get_explicit_self(cx: &ExtCtxt<'_>,
                          span: Span,
-                         self_ptr: &Option<PtrTy>)
+                         self_ptr: &Option<PtrTy<'_>>)
                          -> (P<Expr>, ast::ExplicitSelf) {
     // this constructs a fresh `self` path
     let self_path = cx.expr_self(span);
diff --git a/src/libsyntax_ext/deriving/hash.rs b/src/libsyntax_ext/deriving/hash.rs
index 4af2bd57b00e2..0d4f2ddc3be7b 100644
--- a/src/libsyntax_ext/deriving/hash.rs
+++ b/src/libsyntax_ext/deriving/hash.rs
@@ -1,6 +1,6 @@
-use deriving::{self, pathvec_std, path_std};
-use deriving::generic::*;
-use deriving::generic::ty::*;
+use crate::deriving::{self, pathvec_std, path_std};
+use crate::deriving::generic::*;
+use crate::deriving::generic::ty::*;
 
 use syntax::ast::{Expr, MetaItem, Mutability};
 use syntax::ext::base::{Annotatable, ExtCtxt};
@@ -8,7 +8,7 @@ use syntax::ext::build::AstBuilder;
 use syntax::ptr::P;
 use syntax_pos::Span;
 
-pub fn expand_deriving_hash(cx: &mut ExtCtxt,
+pub fn expand_deriving_hash(cx: &mut ExtCtxt<'_>,
                             span: Span,
                             mitem: &MetaItem,
                             item: &Annotatable,
@@ -50,7 +50,7 @@ pub fn expand_deriving_hash(cx: &mut ExtCtxt,
     hash_trait_def.expand(cx, mitem, item, push);
 }
 
-fn hash_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
+fn hash_substructure(cx: &mut ExtCtxt<'_>, trait_span: Span, substr: &Substructure<'_>) -> P<Expr> {
     let state_expr = match (substr.nonself_args.len(), substr.nonself_args.get(0)) {
         (1, Some(o_f)) => o_f,
         _ => {
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index 7548d43f18444..fff54814a38c4 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -90,7 +90,7 @@ derive_traits! {
 }
 
 #[inline] // because `name` is a compile-time constant
-fn warn_if_deprecated(ecx: &mut ExtCtxt, sp: Span, name: &str) {
+fn warn_if_deprecated(ecx: &mut ExtCtxt<'_>, sp: Span, name: &str) {
     if let Some(replacement) = match name {
         "Encodable" => Some("RustcEncodable"),
         "Decodable" => Some("RustcDecodable"),
@@ -131,16 +131,21 @@ fn hygienic_type_parameter(item: &Annotatable, base: &str) -> String {
 }
 
 /// Constructs an expression that calls an intrinsic
-fn call_intrinsic(cx: &ExtCtxt,
+fn call_intrinsic(cx: &ExtCtxt<'_>,
                   mut span: Span,
                   intrinsic: &str,
                   args: Vec<P<ast::Expr>>)
                   -> P<ast::Expr> {
-    if cx.current_expansion.mark.expn_info().unwrap().allow_internal_unstable {
+    let intrinsic_allowed_via_allow_internal_unstable = cx
+        .current_expansion.mark.expn_info().unwrap()
+        .allow_internal_unstable.map_or(false, |features| features.iter().any(|&s|
+            s == "core_intrinsics"
+        ));
+    if intrinsic_allowed_via_allow_internal_unstable {
         span = span.with_ctxt(cx.backtrace());
     } else { // Avoid instability errors with user defined curstom derives, cc #36316
         let mut info = cx.current_expansion.mark.expn_info().unwrap();
-        info.allow_internal_unstable = true;
+        info.allow_internal_unstable = Some(vec![Symbol::intern("core_intrinsics")].into());
         let mark = Mark::fresh(Mark::root());
         mark.set_expn_info(info);
         span = span.with_ctxt(SyntaxContext::empty().apply_mark(mark));
diff --git a/src/libsyntax_ext/diagnostics.rs b/src/libsyntax_ext/diagnostics.rs
index e8ad4af68508e..9bbd9fdec17d6 100644
--- a/src/libsyntax_ext/diagnostics.rs
+++ b/src/libsyntax_ext/diagnostics.rs
@@ -1,5 +1,7 @@
 #![allow(non_snake_case)]
 
+use syntax::{register_diagnostic, register_long_diagnostics};
+
 // Error messages for EXXXX errors.
 // Each message should start and end with a new line, and be wrapped to 80 characters.
 // In vim you can `:set tw=80` and use `gq` to wrap paragraphs. Use `:set tw=0` to disable.
diff --git a/src/libsyntax_ext/env.rs b/src/libsyntax_ext/env.rs
index 16fb64a5f3912..ccff4aec2c8c7 100644
--- a/src/libsyntax_ext/env.rs
+++ b/src/libsyntax_ext/env.rs
@@ -4,8 +4,7 @@
 //
 
 use syntax::ast::{self, Ident, GenericArg};
-use syntax::ext::base::*;
-use syntax::ext::base;
+use syntax::ext::base::{self, *};
 use syntax::ext::build::AstBuilder;
 use syntax::symbol::{keywords, Symbol};
 use syntax_pos::Span;
@@ -13,7 +12,7 @@ use syntax::tokenstream;
 
 use std::env;
 
-pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
                               sp: Span,
                               tts: &[tokenstream::TokenTree])
                               -> Box<dyn base::MacResult + 'cx> {
@@ -44,7 +43,7 @@ pub fn expand_option_env<'cx>(cx: &'cx mut ExtCtxt,
     MacEager::expr(e)
 }
 
-pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_env<'cx>(cx: &'cx mut ExtCtxt<'_>,
                        sp: Span,
                        tts: &[tokenstream::TokenTree])
                        -> Box<dyn base::MacResult + 'cx> {
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 3e3bca7080fb6..5efa6b36f675d 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -1,9 +1,11 @@
-use self::ArgumentType::*;
-use self::Position::*;
+use ArgumentType::*;
+use Position::*;
 
 use fmt_macros as parse;
 
 use errors::DiagnosticBuilder;
+use errors::Applicability;
+
 use syntax::ast;
 use syntax::ext::base::{self, *};
 use syntax::ext::build::AstBuilder;
@@ -13,7 +15,6 @@ use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax::tokenstream;
 use syntax_pos::{MultiSpan, Span, DUMMY_SP};
-use errors::Applicability;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use std::borrow::Cow;
@@ -184,7 +185,7 @@ fn parse_args<'a>(
 }
 
 impl<'a, 'b> Context<'a, 'b> {
-    fn resolve_name_inplace(&self, p: &mut parse::Piece) {
+    fn resolve_name_inplace(&self, p: &mut parse::Piece<'_>) {
         // NOTE: the `unwrap_or` branch is needed in case of invalid format
         // arguments, e.g., `format_args!("{foo}")`.
         let lookup = |s| *self.names.get(s).unwrap_or(&0);
@@ -208,7 +209,7 @@ impl<'a, 'b> Context<'a, 'b> {
     /// Verifies one piece of a parse string, and remembers it if valid.
     /// All errors are not emitted as fatal so we can continue giving errors
     /// about this and possibly other format strings.
-    fn verify_piece(&mut self, p: &parse::Piece) {
+    fn verify_piece(&mut self, p: &parse::Piece<'_>) {
         match *p {
             parse::String(..) => {}
             parse::NextArgument(ref arg) => {
@@ -231,7 +232,7 @@ impl<'a, 'b> Context<'a, 'b> {
         }
     }
 
-    fn verify_count(&mut self, c: parse::Count) {
+    fn verify_count(&mut self, c: parse::Count<'_>) {
         match c {
             parse::CountImplied |
             parse::CountIs(..) => {}
@@ -244,7 +245,7 @@ impl<'a, 'b> Context<'a, 'b> {
         }
     }
 
-    fn describe_num_args(&self) -> Cow<str> {
+    fn describe_num_args(&self) -> Cow<'_, str> {
         match self.args.len() {
             0 => "no arguments were given".into(),
             1 => "there is 1 argument".into(),
@@ -385,11 +386,11 @@ impl<'a, 'b> Context<'a, 'b> {
         self.count_args_index_offset = sofar;
     }
 
-    fn rtpath(ecx: &ExtCtxt, s: &str) -> Vec<ast::Ident> {
+    fn rtpath(ecx: &ExtCtxt<'_>, s: &str) -> Vec<ast::Ident> {
         ecx.std_path(&["fmt", "rt", "v1", s])
     }
 
-    fn build_count(&self, c: parse::Count) -> P<ast::Expr> {
+    fn build_count(&self, c: parse::Count<'_>) -> P<ast::Expr> {
         let sp = self.macsp;
         let count = |c, arg| {
             let mut path = Context::rtpath(self.ecx, "Count");
@@ -423,10 +424,10 @@ impl<'a, 'b> Context<'a, 'b> {
         self.ecx.expr_str(sp, s)
     }
 
-    /// Build a static `rt::Argument` from a `parse::Piece` or append
+    /// Builds a static `rt::Argument` from a `parse::Piece` or append
     /// to the `literal` string.
     fn build_piece(&mut self,
-                   piece: &parse::Piece,
+                   piece: &parse::Piece<'_>,
                    arg_index_consumed: &mut Vec<usize>)
                    -> Option<P<ast::Expr>> {
         let sp = self.macsp;
@@ -493,7 +494,10 @@ impl<'a, 'b> Context<'a, 'b> {
 
                 let fill = arg.format.fill.unwrap_or(' ');
 
-                if *arg != simple_arg || fill != ' ' {
+                let pos_simple =
+                    arg.position.index() == simple_arg.position.index();
+
+                if !pos_simple || arg.format != simple_arg.format || fill != ' ' {
                     self.all_pieces_simple = false;
                 }
 
@@ -541,7 +545,7 @@ impl<'a, 'b> Context<'a, 'b> {
     }
 
     /// Actually builds the expression which the format_args! block will be
-    /// expanded to
+    /// expanded to.
     fn into_expr(self) -> P<ast::Expr> {
         let mut locals = Vec::with_capacity(
             (0..self.args.len()).map(|i| self.arg_unique_types[i].len()).sum()
@@ -644,7 +648,7 @@ impl<'a, 'b> Context<'a, 'b> {
         self.ecx.expr_call_global(self.macsp, path, fn_args)
     }
 
-    fn format_arg(ecx: &ExtCtxt,
+    fn format_arg(ecx: &ExtCtxt<'_>,
                   macsp: Span,
                   mut sp: Span,
                   ty: &ArgumentType,
@@ -683,7 +687,7 @@ impl<'a, 'b> Context<'a, 'b> {
     }
 }
 
-pub fn expand_format_args<'cx>(ecx: &'cx mut ExtCtxt,
+pub fn expand_format_args<'cx>(ecx: &'cx mut ExtCtxt<'_>,
                                mut sp: Span,
                                tts: &[tokenstream::TokenTree])
                                -> Box<dyn base::MacResult + 'cx> {
@@ -700,14 +704,14 @@ pub fn expand_format_args<'cx>(ecx: &'cx mut ExtCtxt,
 }
 
 pub fn expand_format_args_nl<'cx>(
-    ecx: &'cx mut ExtCtxt,
+    ecx: &'cx mut ExtCtxt<'_>,
     mut sp: Span,
     tts: &[tokenstream::TokenTree],
 ) -> Box<dyn base::MacResult + 'cx> {
     //if !ecx.ecfg.enable_allow_internal_unstable() {
 
     // For some reason, the only one that actually works for `println` is the first check
-    if !sp.allows_unstable()   // the enclosing span is marked as `#[allow_insternal_unsable]`
+    if !sp.allows_unstable("format_args_nl") // the span is marked as `#[allow_insternal_unsable]`
         && !ecx.ecfg.enable_allow_internal_unstable()  // NOTE: when is this enabled?
         && !ecx.ecfg.enable_format_args_nl()  // enabled using `#[feature(format_args_nl]`
     {
@@ -731,7 +735,7 @@ pub fn expand_format_args_nl<'cx>(
 
 /// Take the various parts of `format_args!(efmt, args..., name=names...)`
 /// and construct the appropriate formatting expression.
-pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
+pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt<'_>,
                                     sp: Span,
                                     efmt: P<ast::Expr>,
                                     args: Vec<P<ast::Expr>>,
@@ -760,7 +764,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
                     0 => "{}".to_string(),
                     _ => format!("{}{{}}", "{} ".repeat(args.len())),
                 };
-                err.span_suggestion_with_applicability(
+                err.span_suggestion(
                     fmt_sp.shrink_to_lo(),
                     "you might be missing a string literal to format with",
                     format!("\"{}\", ", sugg_fmt),
@@ -784,7 +788,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
         },
     };
 
-    /// Find the indices of all characters that have been processed and differ between the actual
+    /// Finds the indices of all characters that have been processed and differ between the actual
     /// written code (code snippet) and the `InternedString` that get's processed in the `Parser`
     /// in order to properly synthethise the intra-string `Span`s for error diagnostics.
     fn find_skips(snippet: &str, is_raw: bool) -> Vec<usize> {
@@ -949,7 +953,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
         piece
     }).collect::<Vec<_>>();
 
-    let numbered_position_args = pieces.iter().any(|arg: &parse::Piece| {
+    let numbered_position_args = pieces.iter().any(|arg: &parse::Piece<'_>| {
         match *arg {
             parse::String(_) => false,
             parse::NextArgument(arg) => {
@@ -1077,7 +1081,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
                         ));
                     }
                     if suggestions.len() > 0 {
-                        diag.multipart_suggestion_with_applicability(
+                        diag.multipart_suggestion(
                             "format specifiers use curly braces",
                             suggestions,
                             Applicability::MachineApplicable,
diff --git a/src/libsyntax_ext/format_foreign.rs b/src/libsyntax_ext/format_foreign.rs
index 8ac6d460ec3d9..261b2f373cefd 100644
--- a/src/libsyntax_ext/format_foreign.rs
+++ b/src/libsyntax_ext/format_foreign.rs
@@ -68,7 +68,7 @@ pub mod printf {
         pub position: (usize, usize),
     }
 
-    impl<'a> Format<'a> {
+    impl Format<'_> {
         /// Translate this directive into an equivalent Rust formatting directive.
         ///
         /// Returns `None` in cases where the `printf` directive does not have an exact Rust
@@ -249,12 +249,12 @@ pub mod printf {
             }
         }
 
-        fn translate(&self, s: &mut String) -> ::std::fmt::Result {
+        fn translate(&self, s: &mut String) -> std::fmt::Result {
             use std::fmt::Write;
             match *self {
                 Num::Num(n) => write!(s, "{}", n),
                 Num::Arg(n) => {
-                    let n = n.checked_sub(1).ok_or(::std::fmt::Error)?;
+                    let n = n.checked_sub(1).ok_or(std::fmt::Error)?;
                     write!(s, "{}$", n)
                 },
                 Num::Next => write!(s, "*"),
@@ -263,7 +263,7 @@ pub mod printf {
     }
 
     /// Returns an iterator over all substitutions in a given string.
-    pub fn iter_subs(s: &str) -> Substitutions {
+    pub fn iter_subs(s: &str) -> Substitutions<'_> {
         Substitutions {
             s,
             pos: 0,
@@ -309,7 +309,7 @@ pub mod printf {
     }
 
     /// Parse the next substitution from the input string.
-    pub fn parse_next_substitution(s: &str) -> Option<(Substitution, &str)> {
+    pub fn parse_next_substitution(s: &str) -> Option<(Substitution<'_>, &str)> {
         use self::State::*;
 
         let at = {
@@ -389,7 +389,7 @@ pub mod printf {
         let mut precision: Option<Num> = None;
         let mut length: Option<&str> = None;
         let mut type_: &str = "";
-        let end: Cur;
+        let end: Cur<'_>;
 
         if let Start = state {
             match c {
@@ -575,7 +575,7 @@ pub mod printf {
         Some((Substitution::Format(f), end.slice_after()))
     }
 
-    fn at_next_cp_while<F>(mut cur: Cur, mut pred: F) -> Cur
+    fn at_next_cp_while<F>(mut cur: Cur<'_>, mut pred: F) -> Cur<'_>
     where F: FnMut(char) -> bool {
         loop {
             match cur.next_cp() {
@@ -718,7 +718,7 @@ pub mod printf {
             );
         }
 
-        /// Check that the translations are what we expect.
+        /// Checks that the translations are what we expect.
         #[test]
         fn test_translation() {
             assert_eq_pnsat!("%c", Some("{}"));
@@ -769,7 +769,7 @@ pub mod shell {
         Escape((usize, usize)),
     }
 
-    impl<'a> Substitution<'a> {
+    impl Substitution<'_> {
         pub fn as_str(&self) -> String {
             match self {
                 Substitution::Ordinal(n, _) => format!("${}", n),
@@ -804,7 +804,7 @@ pub mod shell {
     }
 
     /// Returns an iterator over all substitutions in a given string.
-    pub fn iter_subs(s: &str) -> Substitutions {
+    pub fn iter_subs(s: &str) -> Substitutions<'_> {
         Substitutions {
             s,
             pos: 0,
@@ -839,7 +839,7 @@ pub mod shell {
     }
 
     /// Parse the next substitution from the input string.
-    pub fn parse_next_substitution(s: &str) -> Option<(Substitution, &str)> {
+    pub fn parse_next_substitution(s: &str) -> Option<(Substitution<'_>, &str)> {
         let at = {
             let start = s.find('$')?;
             match s[start+1..].chars().next()? {
@@ -868,7 +868,7 @@ pub mod shell {
         }
     }
 
-    fn at_next_cp_while<F>(mut cur: Cur, mut pred: F) -> Cur
+    fn at_next_cp_while<F>(mut cur: Cur<'_>, mut pred: F) -> Cur<'_>
     where F: FnMut(char) -> bool {
         loop {
             match cur.next_cp() {
@@ -962,8 +962,6 @@ pub mod shell {
 }
 
 mod strcursor {
-    use std;
-
     pub struct StrCursor<'a> {
         s: &'a str,
         pub at: usize,
@@ -1028,7 +1026,7 @@ mod strcursor {
         }
     }
 
-    impl<'a> Copy for StrCursor<'a> {}
+    impl Copy for StrCursor<'_> {}
 
     impl<'a> Clone for StrCursor<'a> {
         fn clone(&self) -> StrCursor<'a> {
@@ -1036,8 +1034,8 @@ mod strcursor {
         }
     }
 
-    impl<'a> std::fmt::Debug for StrCursor<'a> {
-        fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
+    impl std::fmt::Debug for StrCursor<'_> {
+        fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
             write!(fmt, "StrCursor({:?} | {:?})", self.slice_before(), self.slice_after())
         }
     }
diff --git a/src/libsyntax_ext/global_asm.rs b/src/libsyntax_ext/global_asm.rs
index 0a12e27c4fc21..2baf530aedae7 100644
--- a/src/libsyntax_ext/global_asm.rs
+++ b/src/libsyntax_ext/global_asm.rs
@@ -9,20 +9,21 @@
 /// therefore apply.
 
 use errors::DiagnosticBuilder;
+
 use syntax::ast;
 use syntax::source_map::respan;
-use syntax::ext::base;
-use syntax::ext::base::*;
+use syntax::ext::base::{self, *};
 use syntax::feature_gate;
 use syntax::parse::token;
 use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 use syntax::tokenstream;
+use smallvec::smallvec;
 
 pub const MACRO: &str = "global_asm";
 
-pub fn expand_global_asm<'cx>(cx: &'cx mut ExtCtxt,
+pub fn expand_global_asm<'cx>(cx: &'cx mut ExtCtxt<'_>,
                               sp: Span,
                               tts: &[tokenstream::TokenTree]) -> Box<dyn base::MacResult + 'cx> {
     if !cx.ecfg.enable_global_asm() {
diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index 17996f2369161..aa472eee3cab3 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -1,8 +1,8 @@
 //! Syntax extensions in the Rust compiler.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+
+#![deny(rust_2018_idioms)]
 
 #![feature(in_band_lifetimes)]
 #![feature(proc_macro_diagnostic)]
@@ -10,24 +10,11 @@
 #![feature(proc_macro_span)]
 #![feature(decl_macro)]
 #![feature(nll)]
-#![feature(str_escape)]
-#![feature(quote)]
 #![feature(rustc_diagnostic_macros)]
 
 #![recursion_limit="256"]
 
-extern crate fmt_macros;
-#[macro_use]
-extern crate syntax;
-extern crate syntax_pos;
 extern crate proc_macro;
-extern crate rustc_data_structures;
-extern crate rustc_errors as errors;
-extern crate rustc_target;
-#[macro_use]
-extern crate smallvec;
-#[macro_use]
-extern crate log;
 
 mod diagnostics;
 
@@ -58,8 +45,7 @@ use syntax::ext::hygiene;
 use syntax::symbol::Symbol;
 
 pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
-                         user_exts: Vec<NamedSyntaxExtension>,
-                         enable_quotes: bool) {
+                         user_exts: Vec<NamedSyntaxExtension>) {
     deriving::register_builtin_derives(resolver);
 
     let mut register = |name, ext| {
@@ -72,7 +58,7 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
                      NormalTT {
                         expander: Box::new($f as MacroExpanderFn),
                         def_info: None,
-                        allow_internal_unstable: false,
+                        allow_internal_unstable: None,
                         allow_internal_unsafe: false,
                         local_inner_macros: false,
                         unstable_feature: None,
@@ -81,24 +67,6 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
         )* }
     }
 
-    if enable_quotes {
-        use syntax::ext::quote::*;
-        register! {
-            quote_tokens: expand_quote_tokens,
-            quote_expr: expand_quote_expr,
-            quote_ty: expand_quote_ty,
-            quote_item: expand_quote_item,
-            quote_pat: expand_quote_pat,
-            quote_arm: expand_quote_arm,
-            quote_stmt: expand_quote_stmt,
-            quote_attr: expand_quote_attr,
-            quote_arg: expand_quote_arg,
-            quote_block: expand_quote_block,
-            quote_meta_item: expand_quote_meta_item,
-            quote_path: expand_quote_path,
-        }
-    }
-
     use syntax::ext::source_util::*;
     register! {
         line: expand_line,
@@ -133,7 +101,9 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
              NormalTT {
                 expander: Box::new(format::expand_format_args),
                 def_info: None,
-                allow_internal_unstable: true,
+                allow_internal_unstable: Some(vec![
+                    Symbol::intern("fmt_internals"),
+                ].into()),
                 allow_internal_unsafe: false,
                 local_inner_macros: false,
                 unstable_feature: None,
@@ -143,7 +113,9 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
              NormalTT {
                  expander: Box::new(format::expand_format_args_nl),
                  def_info: None,
-                 allow_internal_unstable: true,
+                 allow_internal_unstable: Some(vec![
+                     Symbol::intern("fmt_internals"),
+                 ].into()),
                  allow_internal_unsafe: false,
                  local_inner_macros: false,
                  unstable_feature: None,
diff --git a/src/libsyntax_ext/log_syntax.rs b/src/libsyntax_ext/log_syntax.rs
index a143186b9451f..658ce98d26884 100644
--- a/src/libsyntax_ext/log_syntax.rs
+++ b/src/libsyntax_ext/log_syntax.rs
@@ -4,7 +4,7 @@ use syntax::print;
 use syntax::tokenstream;
 use syntax_pos;
 
-pub fn expand_syntax_ext<'cx>(cx: &'cx mut base::ExtCtxt,
+pub fn expand_syntax_ext<'cx>(cx: &'cx mut base::ExtCtxt<'_>,
                               sp: syntax_pos::Span,
                               tts: &[tokenstream::TokenTree])
                               -> Box<dyn base::MacResult + 'cx> {
diff --git a/src/libsyntax_ext/proc_macro_decls.rs b/src/libsyntax_ext/proc_macro_decls.rs
index 1d272712cacc8..d8f8decef39b1 100644
--- a/src/libsyntax_ext/proc_macro_decls.rs
+++ b/src/libsyntax_ext/proc_macro_decls.rs
@@ -1,6 +1,6 @@
 use std::mem;
 
-use errors;
+use crate::deriving;
 
 use syntax::ast::{self, Ident};
 use syntax::attr;
@@ -9,7 +9,7 @@ use syntax::ext::base::ExtCtxt;
 use syntax::ext::build::AstBuilder;
 use syntax::ext::expand::ExpansionConfig;
 use syntax::ext::hygiene::Mark;
-use syntax::fold::Folder;
+use syntax::mut_visit::MutVisitor;
 use syntax::parse::ParseSess;
 use syntax::ptr::P;
 use syntax::symbol::Symbol;
@@ -18,8 +18,6 @@ use syntax::visit::{self, Visitor};
 
 use syntax_pos::{Span, DUMMY_SP};
 
-use deriving;
-
 const PROC_MACRO_KINDS: [&str; 3] = ["proc_macro_derive", "proc_macro_attribute", "proc_macro"];
 
 struct ProcMacroDerive {
@@ -48,6 +46,7 @@ pub fn modify(sess: &ParseSess,
               resolver: &mut dyn (::syntax::ext::base::Resolver),
               mut krate: ast::Crate,
               is_proc_macro_crate: bool,
+              has_proc_macro_decls: bool,
               is_test_crate: bool,
               num_crate_types: usize,
               handler: &errors::Handler) -> ast::Crate {
@@ -64,7 +63,9 @@ pub fn modify(sess: &ParseSess,
             is_proc_macro_crate,
             is_test_crate,
         };
-        visit::walk_crate(&mut collect, &krate);
+        if has_proc_macro_decls || is_proc_macro_crate {
+            visit::walk_crate(&mut collect, &krate);
+        }
         (collect.derives, collect.attr_macros, collect.bang_macros)
     };
 
@@ -85,7 +86,7 @@ pub fn modify(sess: &ParseSess,
     krate
 }
 
-fn is_proc_macro_attr(attr: &ast::Attribute) -> bool {
+pub fn is_proc_macro_attr(attr: &ast::Attribute) -> bool {
     PROC_MACRO_KINDS.iter().any(|kind| attr.check_name(kind))
 }
 
@@ -321,7 +322,7 @@ impl<'a> Visitor<'a> for CollectProcMacros<'a> {
 //          ];
 //      }
 fn mk_decls(
-    cx: &mut ExtCtxt,
+    cx: &mut ExtCtxt<'_>,
     custom_derives: &[ProcMacroDerive],
     custom_attrs: &[ProcMacroDef],
     custom_macros: &[ProcMacroDef],
@@ -331,7 +332,10 @@ fn mk_decls(
         call_site: DUMMY_SP,
         def_site: None,
         format: MacroAttribute(Symbol::intern("proc_macro")),
-        allow_internal_unstable: true,
+        allow_internal_unstable: Some(vec![
+            Symbol::intern("rustc_attrs"),
+            Symbol::intern("proc_macro_internals"),
+        ].into()),
         allow_internal_unsafe: false,
         local_inner_macros: false,
         edition: hygiene::default_edition(),
@@ -409,5 +413,5 @@ fn mk_decls(
         i
     });
 
-    cx.monotonic_expander().fold_item(module).pop().unwrap()
+    cx.monotonic_expander().flat_map_item(module).pop().unwrap()
 }
diff --git a/src/libsyntax_ext/proc_macro_impl.rs b/src/libsyntax_ext/proc_macro_impl.rs
index 60d167d01eebe..f0fc6392cd73f 100644
--- a/src/libsyntax_ext/proc_macro_impl.rs
+++ b/src/libsyntax_ext/proc_macro_impl.rs
@@ -1,27 +1,27 @@
-use errors::FatalError;
+use crate::proc_macro_server;
 
+use errors::FatalError;
 use syntax::source_map::Span;
-use syntax::ext::base::*;
+use syntax::ext::base::{self, *};
 use syntax::tokenstream::TokenStream;
-use syntax::ext::base;
 
-pub const EXEC_STRATEGY: ::proc_macro::bridge::server::SameThread =
-    ::proc_macro::bridge::server::SameThread;
+pub const EXEC_STRATEGY: proc_macro::bridge::server::SameThread =
+    proc_macro::bridge::server::SameThread;
 
 pub struct AttrProcMacro {
-    pub client: ::proc_macro::bridge::client::Client<
-        fn(::proc_macro::TokenStream, ::proc_macro::TokenStream) -> ::proc_macro::TokenStream,
+    pub client: proc_macro::bridge::client::Client<
+        fn(proc_macro::TokenStream, proc_macro::TokenStream) -> proc_macro::TokenStream,
     >,
 }
 
 impl base::AttrProcMacro for AttrProcMacro {
     fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt,
+                   ecx: &'cx mut ExtCtxt<'_>,
                    span: Span,
                    annotation: TokenStream,
                    annotated: TokenStream)
                    -> TokenStream {
-        let server = ::proc_macro_server::Rustc::new(ecx);
+        let server = proc_macro_server::Rustc::new(ecx);
         match self.client.run(&EXEC_STRATEGY, server, annotation, annotated) {
             Ok(stream) => stream,
             Err(e) => {
@@ -39,18 +39,18 @@ impl base::AttrProcMacro for AttrProcMacro {
 }
 
 pub struct BangProcMacro {
-    pub client: ::proc_macro::bridge::client::Client<
-        fn(::proc_macro::TokenStream) -> ::proc_macro::TokenStream,
+    pub client: proc_macro::bridge::client::Client<
+        fn(proc_macro::TokenStream) -> proc_macro::TokenStream,
     >,
 }
 
 impl base::ProcMacro for BangProcMacro {
     fn expand<'cx>(&self,
-                   ecx: &'cx mut ExtCtxt,
+                   ecx: &'cx mut ExtCtxt<'_>,
                    span: Span,
                    input: TokenStream)
                    -> TokenStream {
-        let server = ::proc_macro_server::Rustc::new(ecx);
+        let server = proc_macro_server::Rustc::new(ecx);
         match self.client.run(&EXEC_STRATEGY, server, input) {
             Ok(stream) => stream,
             Err(e) => {
diff --git a/src/libsyntax_ext/proc_macro_server.rs b/src/libsyntax_ext/proc_macro_server.rs
index 158cbc791ef50..fd82dac5ab6d8 100644
--- a/src/libsyntax_ext/proc_macro_server.rs
+++ b/src/libsyntax_ext/proc_macro_server.rs
@@ -1,4 +1,5 @@
-use errors::{self, Diagnostic, DiagnosticBuilder};
+use errors::{Diagnostic, DiagnosticBuilder};
+
 use std::panic;
 
 use proc_macro::bridge::{server, TokenTree};
@@ -11,6 +12,7 @@ use syntax::ast;
 use syntax::ext::base::ExtCtxt;
 use syntax::parse::lexer::comments;
 use syntax::parse::{self, token, ParseSess};
+use syntax::parse::parser::emit_unclosed_delims;
 use syntax::tokenstream::{self, DelimSpan, IsJoint::*, TokenStream, TreeAndJoint};
 use syntax_pos::hygiene::{SyntaxContext, Transparency};
 use syntax_pos::symbol::{keywords, Symbol};
@@ -269,7 +271,7 @@ impl ToInternal<TokenStream> for TokenTree<Group, Punct, Ident, Literal> {
         };
 
         let tree = tokenstream::TokenTree::Token(span, token);
-        TokenStream::Tree(tree, if joint { Joint } else { NonJoint })
+        TokenStream::new(vec![(tree, if joint { Joint } else { NonJoint })])
     }
 }
 
@@ -369,7 +371,7 @@ pub(crate) struct Rustc<'a> {
 }
 
 impl<'a> Rustc<'a> {
-    pub fn new(cx: &'a ExtCtxt) -> Self {
+    pub fn new(cx: &'a ExtCtxt<'_>) -> Self {
         // No way to determine def location for a proc macro right now, so use call location.
         let location = cx.current_expansion.mark.expn_info().unwrap().call_site;
         let to_span = |transparency| {
@@ -408,12 +410,14 @@ impl server::TokenStream for Rustc<'_> {
         stream.is_empty()
     }
     fn from_str(&mut self, src: &str) -> Self::TokenStream {
-        parse::parse_stream_from_source_str(
+        let (tokens, errors) = parse::parse_stream_from_source_str(
             FileName::proc_macro_source_code(src.clone()),
             src.to_string(),
             self.sess,
             Some(self.call_site),
-        )
+        );
+        emit_unclosed_delims(&errors, &self.sess.span_diagnostic);
+        tokens
     }
     fn to_string(&mut self, stream: &Self::TokenStream) -> String {
         stream.to_string()
@@ -650,7 +654,7 @@ impl server::Literal for Rustc<'_> {
     }
 }
 
-impl<'a> server::SourceFile for Rustc<'a> {
+impl server::SourceFile for Rustc<'_> {
     fn eq(&mut self, file1: &Self::SourceFile, file2: &Self::SourceFile) -> bool {
         Lrc::ptr_eq(file1, file2)
     }
diff --git a/src/libsyntax_ext/test.rs b/src/libsyntax_ext/test.rs
index 11c734b299c1e..371862465487b 100644
--- a/src/libsyntax_ext/test.rs
+++ b/src/libsyntax_ext/test.rs
@@ -13,7 +13,7 @@ use syntax::source_map::{ExpnInfo, MacroAttribute};
 use std::iter;
 
 pub fn expand_test(
-    cx: &mut ExtCtxt,
+    cx: &mut ExtCtxt<'_>,
     attr_sp: Span,
     _meta_item: &ast::MetaItem,
     item: Annotatable,
@@ -22,7 +22,7 @@ pub fn expand_test(
 }
 
 pub fn expand_bench(
-    cx: &mut ExtCtxt,
+    cx: &mut ExtCtxt<'_>,
     attr_sp: Span,
     _meta_item: &ast::MetaItem,
     item: Annotatable,
@@ -31,7 +31,7 @@ pub fn expand_bench(
 }
 
 pub fn expand_test_or_bench(
-    cx: &mut ExtCtxt,
+    cx: &mut ExtCtxt<'_>,
     attr_sp: Span,
     item: Annotatable,
     is_bench: bool
@@ -66,7 +66,10 @@ pub fn expand_test_or_bench(
             call_site: DUMMY_SP,
             def_site: None,
             format: MacroAttribute(Symbol::intern("test")),
-            allow_internal_unstable: true,
+            allow_internal_unstable: Some(vec![
+                Symbol::intern("rustc_attrs"),
+                Symbol::intern("test"),
+            ].into()),
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: hygiene::default_edition(),
@@ -180,7 +183,7 @@ pub fn expand_test_or_bench(
         ast::ItemKind::ExternCrate(Some(Symbol::intern("test")))
     );
 
-    debug!("Synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
+    log::debug!("Synthetic test item:\n{}\n", pprust::item_to_string(&test_const));
 
     vec![
         // Access to libtest under a gensymed name
@@ -210,7 +213,7 @@ fn should_fail(i: &ast::Item) -> bool {
     attr::contains_name(&i.attrs, "allow_fail")
 }
 
-fn should_panic(cx: &ExtCtxt, i: &ast::Item) -> ShouldPanic {
+fn should_panic(cx: &ExtCtxt<'_>, i: &ast::Item) -> ShouldPanic {
     match attr::find_by_name(&i.attrs, "should_panic") {
         Some(attr) => {
             let ref sd = cx.parse_sess.span_diagnostic;
@@ -243,7 +246,7 @@ fn should_panic(cx: &ExtCtxt, i: &ast::Item) -> ShouldPanic {
     }
 }
 
-fn has_test_signature(cx: &ExtCtxt, i: &ast::Item) -> bool {
+fn has_test_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
     let has_should_panic_attr = attr::contains_name(&i.attrs, "should_panic");
     let ref sd = cx.parse_sess.span_diagnostic;
     if let ast::ItemKind::Fn(ref decl, ref header, ref generics, _) = i.node {
@@ -296,7 +299,7 @@ fn has_test_signature(cx: &ExtCtxt, i: &ast::Item) -> bool {
     }
 }
 
-fn has_bench_signature(cx: &ExtCtxt, i: &ast::Item) -> bool {
+fn has_bench_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
     let has_sig = if let ast::ItemKind::Fn(ref decl, _, _, _) = i.node {
         // N.B., inadequate check, but we're running
         // well before resolve, can't get too deep.
diff --git a/src/libsyntax_ext/test_case.rs b/src/libsyntax_ext/test_case.rs
index 04e33671872f5..1ed1ab0a07b96 100644
--- a/src/libsyntax_ext/test_case.rs
+++ b/src/libsyntax_ext/test_case.rs
@@ -20,7 +20,7 @@ use syntax::source_map::{ExpnInfo, MacroAttribute};
 use syntax::feature_gate;
 
 pub fn expand(
-    ecx: &mut ExtCtxt,
+    ecx: &mut ExtCtxt<'_>,
     attr_sp: Span,
     _meta_item: &ast::MetaItem,
     anno_item: Annotatable
@@ -41,7 +41,10 @@ pub fn expand(
             call_site: DUMMY_SP,
             def_site: None,
             format: MacroAttribute(Symbol::intern("test_case")),
-            allow_internal_unstable: true,
+            allow_internal_unstable: Some(vec![
+                Symbol::intern("test"),
+                Symbol::intern("rustc_attrs"),
+            ].into()),
             allow_internal_unsafe: false,
             local_inner_macros: false,
             edition: hygiene::default_edition(),
diff --git a/src/libsyntax_ext/trace_macros.rs b/src/libsyntax_ext/trace_macros.rs
index 638d7b5568bfb..4d35daf3de998 100644
--- a/src/libsyntax_ext/trace_macros.rs
+++ b/src/libsyntax_ext/trace_macros.rs
@@ -1,11 +1,10 @@
-use syntax::ext::base::ExtCtxt;
-use syntax::ext::base;
+use syntax::ext::base::{self, ExtCtxt};
 use syntax::feature_gate;
 use syntax::symbol::keywords;
 use syntax_pos::Span;
 use syntax::tokenstream::TokenTree;
 
-pub fn expand_trace_macros(cx: &mut ExtCtxt,
+pub fn expand_trace_macros(cx: &mut ExtCtxt<'_>,
                            sp: Span,
                            tt: &[TokenTree])
                            -> Box<dyn base::MacResult + 'static> {
diff --git a/src/libsyntax_pos/Cargo.toml b/src/libsyntax_pos/Cargo.toml
index 08ee2e0f37626..5658451c54f71 100644
--- a/src/libsyntax_pos/Cargo.toml
+++ b/src/libsyntax_pos/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "syntax_pos"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "syntax_pos"
diff --git a/src/libsyntax_pos/analyze_source_file.rs b/src/libsyntax_pos/analyze_source_file.rs
index 3abd260ac6f8f..353b4e4ab36b3 100644
--- a/src/libsyntax_pos/analyze_source_file.rs
+++ b/src/libsyntax_pos/analyze_source_file.rs
@@ -1,7 +1,7 @@
 use unicode_width::UnicodeWidthChar;
 use super::*;
 
-/// Find all newlines, multi-byte characters, and non-narrow characters in a
+/// Finds all newlines, multi-byte characters, and non-narrow characters in a
 /// SourceFile.
 ///
 /// This function will use an SSE2 enhanced implementation if hardware support
@@ -36,7 +36,7 @@ pub fn analyze_source_file(
     (lines, multi_byte_chars, non_narrow_chars)
 }
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(all(any(target_arch = "x86", target_arch = "x86_64")))] {
         fn analyze_source_file_dispatch(src: &str,
                                     source_file_start_pos: BytePos,
@@ -62,7 +62,7 @@ cfg_if! {
             }
         }
 
-        /// Check 16 byte chunks of text at a time. If the chunk contains
+        /// Checks 16 byte chunks of text at a time. If the chunk contains
         /// something other than printable ASCII characters and newlines, the
         /// function falls back to the generic implementation. Otherwise it uses
         /// SSE2 intrinsics to quickly find all newlines.
diff --git a/src/libsyntax_pos/edition.rs b/src/libsyntax_pos/edition.rs
index f5a745a9cd501..a0b0052f26dab 100644
--- a/src/libsyntax_pos/edition.rs
+++ b/src/libsyntax_pos/edition.rs
@@ -27,7 +27,7 @@ pub const EDITION_NAME_LIST: &str = "2015|2018";
 pub const DEFAULT_EDITION: Edition = Edition::Edition2015;
 
 impl fmt::Display for Edition {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let s = match *self {
             Edition::Edition2015 => "2015",
             Edition::Edition2018 => "2018",
diff --git a/src/libsyntax_pos/hygiene.rs b/src/libsyntax_pos/hygiene.rs
index 6e32a05dee361..6331fe608868f 100644
--- a/src/libsyntax_pos/hygiene.rs
+++ b/src/libsyntax_pos/hygiene.rs
@@ -5,13 +5,14 @@
 //! and definition contexts*. J. Funct. Program. 22, 2 (March 2012), 181-216.
 //! DOI=10.1017/S0956796812000093 <https://doi.org/10.1017/S0956796812000093>
 
-use GLOBALS;
-use Span;
-use edition::{Edition, DEFAULT_EDITION};
-use symbol::{keywords, Symbol};
+use crate::GLOBALS;
+use crate::Span;
+use crate::edition::{Edition, DEFAULT_EDITION};
+use crate::symbol::{keywords, Symbol};
 
 use serialize::{Encodable, Decodable, Encoder, Decoder};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::sync::Lrc;
 use std::{fmt, mem};
 
 /// A SyntaxContext represents a chain of macro expansions (represented by marks).
@@ -31,7 +32,7 @@ struct SyntaxContextData {
     dollar_crate_name: Symbol,
 }
 
-/// A mark is a unique id associated with a macro expansion.
+/// A mark is a unique ID associated with a macro expansion.
 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
 pub struct Mark(u32);
 
@@ -525,7 +526,7 @@ impl SyntaxContext {
 }
 
 impl fmt::Debug for SyntaxContext {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "#{}", self.0)
     }
 }
@@ -550,10 +551,10 @@ pub struct ExpnInfo {
     pub def_site: Option<Span>,
     /// The format with which the macro was invoked.
     pub format: ExpnFormat,
-    /// Whether the macro is allowed to use #[unstable]/feature-gated
-    /// features internally without forcing the whole crate to opt-in
+    /// List of #[unstable]/feature-gated features that the macro is allowed to use
+    /// internally without forcing the whole crate to opt-in
     /// to them.
-    pub allow_internal_unstable: bool,
+    pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
     /// Whether the macro is allowed to use `unsafe` internally
     /// even if the user crate has `#![forbid(unsafe_code)]`.
     pub allow_internal_unsafe: bool,
@@ -590,7 +591,7 @@ pub enum CompilerDesugaringKind {
     QuestionMark,
     TryBlock,
     /// Desugaring of an `impl Trait` in return type position
-    /// to an `existential type Foo: Trait;` + replacing the
+    /// to an `existential type Foo: Trait;` and replacing the
     /// `impl Trait` with `Foo`.
     ExistentialReturnType,
     Async,
diff --git a/src/libsyntax_pos/lib.rs b/src/libsyntax_pos/lib.rs
index 6a41a93f0b4fd..f4771a52034d8 100644
--- a/src/libsyntax_pos/lib.rs
+++ b/src/libsyntax_pos/lib.rs
@@ -4,9 +4,9 @@
 //!
 //! This API is completely unstable and subject to change.
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-      html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-      html_root_url = "https://doc.rust-lang.org/nightly/")]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
+
+#![deny(rust_2018_idioms)]
 
 #![feature(const_fn)]
 #![feature(crate_visibility_modifier)]
@@ -19,23 +19,11 @@
 #![feature(step_trait)]
 #![cfg_attr(not(stage0), feature(stdsimd))]
 
-extern crate arena;
-#[macro_use]
-extern crate rustc_data_structures;
-
-#[macro_use]
-extern crate scoped_tls;
-
 use serialize::{Encodable, Decodable, Encoder, Decoder};
 
-extern crate serialize;
+#[allow(unused_extern_crates)]
 extern crate serialize as rustc_serialize; // used by deriving
 
-#[macro_use]
-extern crate cfg_if;
-
-extern crate unicode_width;
-
 pub mod edition;
 pub mod hygiene;
 pub use hygiene::{Mark, SyntaxContext, ExpnInfo, ExpnFormat, CompilerDesugaringKind};
@@ -74,13 +62,13 @@ impl Globals {
     }
 }
 
-scoped_thread_local!(pub static GLOBALS: Globals);
+scoped_tls::scoped_thread_local!(pub static GLOBALS: Globals);
 
 /// Differentiates between real files and common virtual files.
 #[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash, RustcDecodable, RustcEncodable)]
 pub enum FileName {
     Real(PathBuf),
-    /// A macro.  This includes the full name of the macro, so that there are no clashes.
+    /// A macro. This includes the full name of the macro, so that there are no clashes.
     Macros(String),
     /// Call to `quote!`.
     QuoteExpansion(u64),
@@ -100,8 +88,8 @@ pub enum FileName {
 }
 
 impl std::fmt::Display for FileName {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
-        use self::FileName::*;
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use FileName::*;
         match *self {
             Real(ref path) => write!(fmt, "{}", path.display()),
             Macros(ref name) => write!(fmt, "<{} macros>", name),
@@ -127,7 +115,7 @@ impl From<PathBuf> for FileName {
 
 impl FileName {
     pub fn is_real(&self) -> bool {
-        use self::FileName::*;
+        use FileName::*;
         match *self {
             Real(_) => true,
             Macros(_) |
@@ -143,7 +131,7 @@ impl FileName {
     }
 
     pub fn is_macros(&self) -> bool {
-        use self::FileName::*;
+        use FileName::*;
         match *self {
             Real(_) |
             Anon(_) |
@@ -238,9 +226,9 @@ impl SpanData {
 // The interner is pointed to by a thread local value which is only set on the main thread
 // with parallelization is disabled. So we don't allow `Span` to transfer between threads
 // to avoid panics and other errors, even though it would be memory safe to do so.
-#[cfg(not(parallel_queries))]
+#[cfg(not(parallel_compiler))]
 impl !Send for Span {}
-#[cfg(not(parallel_queries))]
+#[cfg(not(parallel_compiler))]
 impl !Sync for Span {}
 
 impl PartialOrd for Span {
@@ -317,21 +305,21 @@ impl Span {
         if self.is_dummy() { other } else { self }
     }
 
-    /// Return `true` if `self` fully encloses `other`.
+    /// Returns `true` if `self` fully encloses `other`.
     pub fn contains(self, other: Span) -> bool {
         let span = self.data();
         let other = other.data();
         span.lo <= other.lo && other.hi <= span.hi
     }
 
-    /// Return `true` if `self` touches `other`.
+    /// Returns `true` if `self` touches `other`.
     pub fn overlaps(self, other: Span) -> bool {
         let span = self.data();
         let other = other.data();
         span.lo < other.hi && other.lo < span.hi
     }
 
-    /// Return true if the spans are equal with regards to the source text.
+    /// Returns `true` if the spans are equal with regards to the source text.
     ///
     /// Use this instead of `==` when either span could be generated code,
     /// and you only care that they point to the same bytes of source text.
@@ -352,7 +340,7 @@ impl Span {
         }
     }
 
-    /// Return the source span -- this is either the supplied span, or the span for
+    /// Returns the source span -- this is either the supplied span, or the span for
     /// the macro callsite that expanded to it.
     pub fn source_callsite(self) -> Span {
         self.ctxt().outer().expn_info().map(|info| info.call_site.source_callsite()).unwrap_or(self)
@@ -380,7 +368,7 @@ impl Span {
         self.edition() >= edition::Edition::Edition2018
     }
 
-    /// Return the source callee.
+    /// Returns the source callee.
     ///
     /// Returns `None` if the supplied span has no expansion trace,
     /// else returns the `ExpnInfo` for the macro definition
@@ -395,17 +383,21 @@ impl Span {
         self.ctxt().outer().expn_info().map(source_callee)
     }
 
-    /// Check if a span is "internal" to a macro in which `#[unstable]`
+    /// Checks if a span is "internal" to a macro in which `#[unstable]`
     /// items can be used (that is, a macro marked with
     /// `#[allow_internal_unstable]`).
-    pub fn allows_unstable(&self) -> bool {
+    pub fn allows_unstable(&self, feature: &str) -> bool {
         match self.ctxt().outer().expn_info() {
-            Some(info) => info.allow_internal_unstable,
+            Some(info) => info
+                .allow_internal_unstable
+                .map_or(false, |features| features.iter().any(|&f|
+                    f == feature || f == "allow_internal_unstable_backcompat_hack"
+                )),
             None => false,
         }
     }
 
-    /// Check if this span arises from a compiler desugaring of kind `kind`.
+    /// Checks if this span arises from a compiler desugaring of kind `kind`.
     pub fn is_compiler_desugaring(&self, kind: CompilerDesugaringKind) -> bool {
         match self.ctxt().outer().expn_info() {
             Some(info) => match info.format {
@@ -416,7 +408,7 @@ impl Span {
         }
     }
 
-    /// Return the compiler desugaring that created this span, or `None`
+    /// Returns the compiler desugaring that created this span, or `None`
     /// if this span is not from a desugaring.
     pub fn compiler_desugaring_kind(&self) -> Option<CompilerDesugaringKind> {
         match self.ctxt().outer().expn_info() {
@@ -428,7 +420,7 @@ impl Span {
         }
     }
 
-    /// Check if a span is "internal" to a macro in which `unsafe`
+    /// Checks if a span is "internal" to a macro in which `unsafe`
     /// can be used without triggering the `unsafe_code` lint
     //  (that is, a macro marked with `#[allow_internal_unsafe]`).
     pub fn allows_unsafe(&self) -> bool {
@@ -462,7 +454,7 @@ impl Span {
         result
     }
 
-    /// Return a `Span` that would enclose both `self` and `end`.
+    /// Returns a `Span` that would enclose both `self` and `end`.
     pub fn to(self, end: Span) -> Span {
         let span_data = self.data();
         let end_data = end.data();
@@ -485,7 +477,7 @@ impl Span {
         )
     }
 
-    /// Return a `Span` between the end of `self` to the beginning of `end`.
+    /// Returns a `Span` between the end of `self` to the beginning of `end`.
     pub fn between(self, end: Span) -> Span {
         let span = self.data();
         let end = end.data();
@@ -496,7 +488,7 @@ impl Span {
         )
     }
 
-    /// Return a `Span` between the beginning of `self` to the beginning of `end`.
+    /// Returns a `Span` between the beginning of `self` to the beginning of `end`.
     pub fn until(self, end: Span) -> Span {
         let span = self.data();
         let end = end.data();
@@ -611,7 +603,7 @@ impl serialize::UseSpecializedDecodable for Span {
     }
 }
 
-pub fn default_span_debug(span: Span, f: &mut fmt::Formatter) -> fmt::Result {
+pub fn default_span_debug(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     f.debug_struct("Span")
         .field("lo", &span.lo())
         .field("hi", &span.hi())
@@ -620,13 +612,13 @@ pub fn default_span_debug(span: Span, f: &mut fmt::Formatter) -> fmt::Result {
 }
 
 impl fmt::Debug for Span {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         SPAN_DEBUG.with(|span_debug| span_debug.get()(*self, f))
     }
 }
 
 impl fmt::Debug for SpanData {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         SPAN_DEBUG.with(|span_debug| span_debug.get()(Span::new(self.lo, self.hi, self.ctxt), f))
     }
 }
@@ -668,6 +660,11 @@ impl MultiSpan {
         &self.primary_spans
     }
 
+    /// Returns `true` if any of the primary spans are displayable.
+    pub fn has_primary_spans(&self) -> bool {
+        self.primary_spans.iter().any(|sp| !sp.is_dummy())
+    }
+
     /// Returns `true` if this contains only a dummy primary span with any hygienic context.
     pub fn is_dummy(&self) -> bool {
         let mut is_dummy = true;
@@ -680,7 +677,7 @@ impl MultiSpan {
     }
 
     /// Replaces all occurrences of one Span with another. Used to move `Span`s in areas that don't
-    /// display well (like std macros). Returns true if replacements occurred.
+    /// display well (like std macros). Returns whether replacements occurred.
     pub fn replace(&mut self, before: Span, after: Span) -> bool {
         let mut replacements_occurred = false;
         for primary_span in &mut self.primary_spans {
@@ -726,6 +723,11 @@ impl MultiSpan {
 
         span_labels
     }
+
+    /// Returns `true` if any of the span labels is displayable.
+    pub fn has_span_labels(&self) -> bool {
+        self.span_labels.iter().any(|(sp, _)| !sp.is_dummy())
+    }
 }
 
 impl From<Span> for MultiSpan {
@@ -851,7 +853,7 @@ pub struct SourceFile {
     /// originate from files has names between angle brackets by convention
     /// (e.g., `<anon>`).
     pub name: FileName,
-    /// True if the `name` field above has been modified by `--remap-path-prefix`.
+    /// `true` if the `name` field above has been modified by `--remap-path-prefix`.
     pub name_was_remapped: bool,
     /// The unmapped path of the file that the source came from.
     /// Set to `None` if the `SourceFile` was imported from an external crate.
@@ -999,7 +1001,7 @@ impl Decodable for SourceFile {
                 // `crate_of_origin` has to be set by the importer.
                 // This value matches up with rustc::hir::def_id::INVALID_CRATE.
                 // That constant is not available here unfortunately :(
-                crate_of_origin: ::std::u32::MAX - 1,
+                crate_of_origin: std::u32::MAX - 1,
                 start_pos,
                 end_pos,
                 src: None,
@@ -1015,7 +1017,7 @@ impl Decodable for SourceFile {
 }
 
 impl fmt::Debug for SourceFile {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(fmt, "SourceFile({})", self.name)
     }
 }
@@ -1060,7 +1062,7 @@ impl SourceFile {
         }
     }
 
-    /// Return the `BytePos` of the beginning of the current line.
+    /// Returns the `BytePos` of the beginning of the current line.
     pub fn line_begin_pos(&self, pos: BytePos) -> BytePos {
         let line_index = self.lookup_line(pos).unwrap();
         self.lines[line_index]
@@ -1099,9 +1101,9 @@ impl SourceFile {
         }
     }
 
-    /// Get a line from the list of pre-computed line-beginnings.
+    /// Gets a line from the list of pre-computed line-beginnings.
     /// The line number here is 0-based.
-    pub fn get_line(&self, line_number: usize) -> Option<Cow<str>> {
+    pub fn get_line(&self, line_number: usize) -> Option<Cow<'_, str>> {
         fn get_until_newline(src: &str, begin: usize) -> &str {
             // We can't use `lines.get(line_number+1)` because we might
             // be parsing when we call this function and thus the current
@@ -1147,7 +1149,7 @@ impl SourceFile {
         self.lines.len()
     }
 
-    /// Find the line containing the given position. The return value is the
+    /// Finds the line containing the given position. The return value is the
     /// index into the `lines` array of this `SourceFile`, not the 1-based line
     /// number. If the source_file is empty or the position is located before the
     /// first line, `None` is returned.
@@ -1184,7 +1186,7 @@ impl SourceFile {
     }
 }
 
-/// Remove utf-8 BOM if any.
+/// Removes UTF-8 BOM, if any.
 fn remove_bom(src: &mut String) {
     if src.starts_with("\u{feff}") {
         src.drain(..3);
@@ -1343,7 +1345,7 @@ pub struct FileLines {
     pub lines: Vec<LineInfo>
 }
 
-thread_local!(pub static SPAN_DEBUG: Cell<fn(Span, &mut fmt::Formatter) -> fmt::Result> =
+thread_local!(pub static SPAN_DEBUG: Cell<fn(Span, &mut fmt::Formatter<'_>) -> fmt::Result> =
                 Cell::new(default_span_debug));
 
 #[derive(Debug)]
diff --git a/src/libsyntax_pos/span_encoding.rs b/src/libsyntax_pos/span_encoding.rs
index 8cb3bc2144da1..03d7a9eb74238 100644
--- a/src/libsyntax_pos/span_encoding.rs
+++ b/src/libsyntax_pos/span_encoding.rs
@@ -4,9 +4,9 @@
 // The encoding format for inline spans were obtained by optimizing over crates in rustc/libstd.
 // See https://internals.rust-lang.org/t/rfc-compiler-refactoring-spans/1357/28
 
-use GLOBALS;
-use {BytePos, SpanData};
-use hygiene::SyntaxContext;
+use crate::GLOBALS;
+use crate::{BytePos, SpanData};
+use crate::hygiene::SyntaxContext;
 
 use rustc_data_structures::fx::FxHashMap;
 use std::hash::{Hash, Hasher};
diff --git a/src/libsyntax_pos/symbol.rs b/src/libsyntax_pos/symbol.rs
index e741b79bd4c45..c5301f9f174c0 100644
--- a/src/libsyntax_pos/symbol.rs
+++ b/src/libsyntax_pos/symbol.rs
@@ -5,6 +5,7 @@
 use arena::DroplessArena;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::indexed_vec::Idx;
+use rustc_data_structures::newtype_index;
 use serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use std::fmt;
@@ -12,8 +13,8 @@ use std::str;
 use std::cmp::{PartialEq, Ordering, PartialOrd, Ord};
 use std::hash::{Hash, Hasher};
 
-use hygiene::SyntaxContext;
-use {Span, DUMMY_SP, GLOBALS};
+use crate::hygiene::SyntaxContext;
+use crate::{Span, DUMMY_SP, GLOBALS};
 
 #[derive(Copy, Clone, Eq)]
 pub struct Ident {
@@ -42,7 +43,7 @@ impl Ident {
         Ident::with_empty_ctxt(Symbol::intern(string))
     }
 
-    /// Replace `lo` and `hi` with those from `span`, but keep hygiene context.
+    /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
     pub fn with_span_pos(self, span: Span) -> Ident {
         Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
     }
@@ -100,13 +101,13 @@ impl Hash for Ident {
 }
 
 impl fmt::Debug for Ident {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}{:?}", self.name, self.span.ctxt())
     }
 }
 
 impl fmt::Display for Ident {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&self.name, f)
     }
 }
@@ -134,12 +135,12 @@ impl Decodable for Ident {
     }
 }
 
-/// A symbol is an interned or gensymed string. The use of newtype_index! means
-/// that Option<Symbol> only takes up 4 bytes, because newtype_index! reserves
+/// A symbol is an interned or gensymed string. The use of `newtype_index!` means
+/// that `Option<Symbol>` only takes up 4 bytes, because `newtype_index! reserves
 /// the last 256 values for tagging purposes.
 ///
-/// Note that Symbol cannot be a newtype_index! directly because it implements
-/// fmt::Debug, Encodable, and Decodable in special ways.
+/// Note that `Symbol` cannot directly be a `newtype_index!` because it implements
+/// `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Symbol(SymbolIndex);
 
@@ -150,9 +151,9 @@ newtype_index! {
 // The interner is pointed to by a thread local value which is only set on the main thread
 // with parallelization is disabled. So we don't allow `Symbol` to transfer between threads
 // to avoid panics and other errors, even though it would be memory safe to do so.
-#[cfg(not(parallel_queries))]
+#[cfg(not(parallel_compiler))]
 impl !Send for Symbol { }
-#[cfg(not(parallel_queries))]
+#[cfg(not(parallel_compiler))]
 impl !Sync for Symbol { }
 
 impl Symbol {
@@ -169,7 +170,7 @@ impl Symbol {
         with_interner(|interner| interner.interned(self))
     }
 
-    /// Gensyms a new usize, using the current interner.
+    /// Gensyms a new `usize`, using the current interner.
     pub fn gensym(string: &str) -> Self {
         with_interner(|interner| interner.gensym(string))
     }
@@ -181,7 +182,7 @@ impl Symbol {
     pub fn as_str(self) -> LocalInternedString {
         with_interner(|interner| unsafe {
             LocalInternedString {
-                string: ::std::mem::transmute::<&str, &str>(interner.get(self))
+                string: std::mem::transmute::<&str, &str>(interner.get(self))
             }
         })
     }
@@ -198,7 +199,7 @@ impl Symbol {
 }
 
 impl fmt::Debug for Symbol {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
         if is_gensymed {
             write!(f, "{}({:?})", self, self.0)
@@ -209,7 +210,7 @@ impl fmt::Debug for Symbol {
 }
 
 impl fmt::Display for Symbol {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(&self.as_str(), f)
     }
 }
@@ -226,7 +227,7 @@ impl Decodable for Symbol {
     }
 }
 
-impl<T: ::std::ops::Deref<Target=str>> PartialEq<T> for Symbol {
+impl<T: std::ops::Deref<Target=str>> PartialEq<T> for Symbol {
     fn eq(&self, other: &T) -> bool {
         self.as_str() == other.deref()
     }
@@ -335,7 +336,7 @@ macro_rules! declare_keywords {(
             };
         )*
 
-        impl ::std::str::FromStr for Keyword {
+        impl std::str::FromStr for Keyword {
             type Err = ();
 
             fn from_str(s: &str) -> Result<Self, ()> {
@@ -519,40 +520,40 @@ impl LocalInternedString {
     }
 }
 
-impl<U: ?Sized> ::std::convert::AsRef<U> for LocalInternedString
+impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
 where
-    str: ::std::convert::AsRef<U>
+    str: std::convert::AsRef<U>
 {
     fn as_ref(&self) -> &U {
         self.string.as_ref()
     }
 }
 
-impl<T: ::std::ops::Deref<Target = str>> ::std::cmp::PartialEq<T> for LocalInternedString {
+impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
     fn eq(&self, other: &T) -> bool {
         self.string == other.deref()
     }
 }
 
-impl ::std::cmp::PartialEq<LocalInternedString> for str {
+impl std::cmp::PartialEq<LocalInternedString> for str {
     fn eq(&self, other: &LocalInternedString) -> bool {
         self == other.string
     }
 }
 
-impl<'a> ::std::cmp::PartialEq<LocalInternedString> for &'a str {
+impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
     fn eq(&self, other: &LocalInternedString) -> bool {
         *self == other.string
     }
 }
 
-impl ::std::cmp::PartialEq<LocalInternedString> for String {
+impl std::cmp::PartialEq<LocalInternedString> for String {
     fn eq(&self, other: &LocalInternedString) -> bool {
         self == other.string
     }
 }
 
-impl<'a> ::std::cmp::PartialEq<LocalInternedString> for &'a String {
+impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
     fn eq(&self, other: &LocalInternedString) -> bool {
         *self == other.string
     }
@@ -561,19 +562,19 @@ impl<'a> ::std::cmp::PartialEq<LocalInternedString> for &'a String {
 impl !Send for LocalInternedString {}
 impl !Sync for LocalInternedString {}
 
-impl ::std::ops::Deref for LocalInternedString {
+impl std::ops::Deref for LocalInternedString {
     type Target = str;
     fn deref(&self) -> &str { self.string }
 }
 
 impl fmt::Debug for LocalInternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Debug::fmt(self.string, f)
     }
 }
 
 impl fmt::Display for LocalInternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self.string, f)
     }
 }
@@ -640,7 +641,7 @@ impl Ord for InternedString {
     }
 }
 
-impl<T: ::std::ops::Deref<Target = str>> PartialEq<T> for InternedString {
+impl<T: std::ops::Deref<Target = str>> PartialEq<T> for InternedString {
     fn eq(&self, other: &T) -> bool {
         self.with(|string| string == other.deref())
     }
@@ -676,20 +677,20 @@ impl<'a> PartialEq<InternedString> for &'a String {
     }
 }
 
-impl ::std::convert::From<InternedString> for String {
+impl std::convert::From<InternedString> for String {
     fn from(val: InternedString) -> String {
         val.as_symbol().to_string()
     }
 }
 
 impl fmt::Debug for InternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.with(|str| fmt::Debug::fmt(&str, f))
     }
 }
 
 impl fmt::Display for InternedString {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.with(|str| fmt::Display::fmt(&str, f))
     }
 }
@@ -709,7 +710,7 @@ impl Encodable for InternedString {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use Globals;
+    use crate::Globals;
 
     #[test]
     fn interner_tests() {
diff --git a/src/libterm/Cargo.toml b/src/libterm/Cargo.toml
index 8021e814c0899..4eba9a9d79cc4 100644
--- a/src/libterm/Cargo.toml
+++ b/src/libterm/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "term"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "term"
diff --git a/src/libterm/lib.rs b/src/libterm/lib.rs
index 115dffa579947..711716d9b926c 100644
--- a/src/libterm/lib.rs
+++ b/src/libterm/lib.rs
@@ -30,27 +30,25 @@
 //! [win]: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682010%28v=vs.85%29.aspx
 //! [ti]: https://en.wikipedia.org/wiki/Terminfo
 
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/",
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/",
        html_playground_url = "https://play.rust-lang.org/",
        test(attr(deny(warnings))))]
 #![deny(missing_docs)]
 
+#![deny(rust_2018_idioms)]
+
 #![cfg_attr(windows, feature(libc))]
 // Handle rustfmt skips
 #![feature(custom_attribute)]
-#![feature(nll)]
 #![allow(unused_attributes)]
 
 use std::io::prelude::*;
+use std::io::{self, Stdout, Stderr};
 
 pub use terminfo::TerminfoTerminal;
 #[cfg(windows)]
 pub use win::WinConsole;
 
-use std::io::{self, Stdout, Stderr};
-
 pub mod terminfo;
 
 #[cfg(windows)]
@@ -62,14 +60,14 @@ pub type StdoutTerminal = dyn Terminal<Output = Stdout> + Send;
 pub type StderrTerminal = dyn Terminal<Output = Stderr> + Send;
 
 #[cfg(not(windows))]
-/// Return a Terminal wrapping stdout, or None if a terminal couldn't be
+/// Returns a Terminal wrapping stdout, or None if a terminal couldn't be
 /// opened.
 pub fn stdout() -> Option<Box<StdoutTerminal>> {
     TerminfoTerminal::new(io::stdout()).map(|t| Box::new(t) as Box<StdoutTerminal>)
 }
 
 #[cfg(windows)]
-/// Return a Terminal wrapping stdout, or None if a terminal couldn't be
+/// Returns a Terminal wrapping stdout, or None if a terminal couldn't be
 /// opened.
 pub fn stdout() -> Option<Box<StdoutTerminal>> {
     TerminfoTerminal::new(io::stdout())
@@ -78,14 +76,14 @@ pub fn stdout() -> Option<Box<StdoutTerminal>> {
 }
 
 #[cfg(not(windows))]
-/// Return a Terminal wrapping stderr, or None if a terminal couldn't be
+/// Returns a Terminal wrapping stderr, or None if a terminal couldn't be
 /// opened.
 pub fn stderr() -> Option<Box<StderrTerminal>> {
     TerminfoTerminal::new(io::stderr()).map(|t| Box::new(t) as Box<StderrTerminal>)
 }
 
 #[cfg(windows)]
-/// Return a Terminal wrapping stderr, or None if a terminal couldn't be
+/// Returns a Terminal wrapping stderr, or None if a terminal couldn't be
 /// opened.
 pub fn stderr() -> Option<Box<StderrTerminal>> {
     TerminfoTerminal::new(io::stderr())
@@ -172,12 +170,12 @@ pub trait Terminal: Write {
     /// if there was an I/O error.
     fn bg(&mut self, color: color::Color) -> io::Result<bool>;
 
-    /// Sets the given terminal attribute, if supported.  Returns `Ok(true)`
+    /// Sets the given terminal attribute, if supported. Returns `Ok(true)`
     /// if the attribute was supported, `Ok(false)` otherwise, and `Err(e)` if
     /// there was an I/O error.
     fn attr(&mut self, attr: Attr) -> io::Result<bool>;
 
-    /// Returns whether the given terminal attribute is supported.
+    /// Returns `true` if the given terminal attribute is supported.
     fn supports_attr(&self, attr: Attr) -> bool;
 
     /// Resets all terminal attributes and colors to their defaults.
diff --git a/src/libterm/terminfo/mod.rs b/src/libterm/terminfo/mod.rs
index eaa96df3f3bad..be90195065eb7 100644
--- a/src/libterm/terminfo/mod.rs
+++ b/src/libterm/terminfo/mod.rs
@@ -5,18 +5,16 @@ use std::env;
 use std::error;
 use std::fmt;
 use std::fs::File;
-use std::io::prelude::*;
-use std::io;
-use std::io::BufReader;
+use std::io::{self, prelude::*, BufReader};
 use std::path::Path;
 
-use Attr;
-use color;
-use Terminal;
-use self::searcher::get_dbpath_for_term;
-use self::parser::compiled::{parse, msys_terminfo};
-use self::parm::{expand, Variables, Param};
+use crate::Attr;
+use crate::color;
+use crate::Terminal;
 
+use searcher::get_dbpath_for_term;
+use parser::compiled::{parse, msys_terminfo};
+use parm::{expand, Variables, Param};
 
 /// A parsed terminfo database entry.
 #[derive(Debug)]
@@ -49,7 +47,7 @@ impl error::Error for Error {
     }
 
     fn cause(&self) -> Option<&dyn error::Error> {
-        use self::Error::*;
+        use Error::*;
         match *self {
             IoError(ref e) => Some(e),
             _ => None,
@@ -58,8 +56,8 @@ impl error::Error for Error {
 }
 
 impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        use self::Error::*;
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        use Error::*;
         match *self {
             TermUnset => Ok(()),
             MalformedTerminfo(ref e) => e.fmt(f),
@@ -69,7 +67,7 @@ impl fmt::Display for Error {
 }
 
 impl TermInfo {
-    /// Create a TermInfo based on current environment.
+    /// Creates a TermInfo based on current environment.
     pub fn from_env() -> Result<TermInfo, Error> {
         let term = match env::var("TERM") {
             Ok(name) => TermInfo::from_name(&name),
@@ -84,7 +82,7 @@ impl TermInfo {
         }
     }
 
-    /// Create a TermInfo for the named terminal.
+    /// Creates a TermInfo for the named terminal.
     pub fn from_name(name: &str) -> Result<TermInfo, Error> {
         get_dbpath_for_term(name)
             .ok_or_else(|| {
@@ -211,7 +209,7 @@ impl<T: Write + Send> Terminal for TerminfoTerminal<T> {
 }
 
 impl<T: Write + Send> TerminfoTerminal<T> {
-    /// Create a new TerminfoTerminal with the given TermInfo and Write.
+    /// Creates a new TerminfoTerminal with the given TermInfo and Write.
     pub fn new_with_terminfo(out: T, terminfo: TermInfo) -> TerminfoTerminal<T> {
         let nc = if terminfo.strings.contains_key("setaf") &&
                     terminfo.strings.contains_key("setab") {
@@ -227,7 +225,7 @@ impl<T: Write + Send> TerminfoTerminal<T> {
         }
     }
 
-    /// Create a new TerminfoTerminal for the current environment with the given Write.
+    /// Creates a new TerminfoTerminal for the current environment with the given Write.
     ///
     /// Returns `None` when the terminfo cannot be found or parsed.
     pub fn new(out: T) -> Option<TerminfoTerminal<T>> {
diff --git a/src/libterm/terminfo/parm.rs b/src/libterm/terminfo/parm.rs
index 434dd4a9fbc99..28229bd87b0a5 100644
--- a/src/libterm/terminfo/parm.rs
+++ b/src/libterm/terminfo/parm.rs
@@ -40,23 +40,27 @@ pub enum Param {
 /// Container for static and dynamic variable arrays
 pub struct Variables {
     /// Static variables A-Z
-    sta: [Param; 26],
+    sta_va: [Param; 26],
     /// Dynamic variables a-z
-    dyn: [Param; 26],
+    dyn_va: [Param; 26],
 }
 
 impl Variables {
-    /// Return a new zero-initialized Variables
+    /// Returns a new zero-initialized Variables
     pub fn new() -> Variables {
         Variables {
-            sta: [Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0)],
-            dyn: [Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
-                  Number(0), Number(0), Number(0), Number(0), Number(0)],
+            sta_va: [
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0)
+            ],
+            dyn_va: [
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0), Number(0), Number(0),
+                Number(0), Number(0), Number(0), Number(0), Number(0)
+            ],
         }
     }
 }
@@ -249,14 +253,14 @@ pub fn expand(cap: &[u8], params: &[Param], vars: &mut Variables) -> Result<Vec<
                 if cur >= 'A' && cur <= 'Z' {
                     if let Some(arg) = stack.pop() {
                         let idx = (cur as u8) - b'A';
-                        vars.sta[idx as usize] = arg;
+                        vars.sta_va[idx as usize] = arg;
                     } else {
                         return Err("stack is empty".to_string());
                     }
                 } else if cur >= 'a' && cur <= 'z' {
                     if let Some(arg) = stack.pop() {
                         let idx = (cur as u8) - b'a';
-                        vars.dyn[idx as usize] = arg;
+                        vars.dyn_va[idx as usize] = arg;
                     } else {
                         return Err("stack is empty".to_string());
                     }
@@ -267,10 +271,10 @@ pub fn expand(cap: &[u8], params: &[Param], vars: &mut Variables) -> Result<Vec<
             GetVar => {
                 if cur >= 'A' && cur <= 'Z' {
                     let idx = (cur as u8) - b'A';
-                    stack.push(vars.sta[idx as usize].clone());
+                    stack.push(vars.sta_va[idx as usize].clone());
                 } else if cur >= 'a' && cur <= 'z' {
                     let idx = (cur as u8) - b'a';
-                    stack.push(vars.dyn[idx as usize].clone());
+                    stack.push(vars.dyn_va[idx as usize].clone());
                 } else {
                     return Err("bad variable name in %g".to_string());
                 }
diff --git a/src/libterm/terminfo/parser/compiled.rs b/src/libterm/terminfo/parser/compiled.rs
index 63d018312697b..a8c21e55556d3 100644
--- a/src/libterm/terminfo/parser/compiled.rs
+++ b/src/libterm/terminfo/parser/compiled.rs
@@ -3,14 +3,14 @@
 //! ncurses-compatible compiled terminfo format parsing (term(5))
 
 use std::collections::HashMap;
-use std::io::prelude::*;
 use std::io;
+use std::io::prelude::*;
 use super::super::TermInfo;
 
 // These are the orders ncurses uses in its compiled format (as of 5.9). Not sure if portable.
 
 #[rustfmt_skip]
-pub static boolfnames: &'static[&'static str] = &["auto_left_margin", "auto_right_margin",
+pub static boolfnames: &[&str] = &["auto_left_margin", "auto_right_margin",
     "no_esc_ctlc", "ceol_standout_glitch", "eat_newline_glitch", "erase_overstrike", "generic_type",
     "hard_copy", "has_meta_key", "has_status_line", "insert_null_glitch", "memory_above",
     "memory_below", "move_insert_mode", "move_standout_mode", "over_strike", "status_line_esc_ok",
@@ -23,13 +23,13 @@ pub static boolfnames: &'static[&'static str] = &["auto_left_margin", "auto_righ
     "return_does_clr_eol"];
 
 #[rustfmt_skip]
-pub static boolnames: &'static[&'static str] = &["bw", "am", "xsb", "xhp", "xenl", "eo",
+pub static boolnames: &[&str] = &["bw", "am", "xsb", "xhp", "xenl", "eo",
     "gn", "hc", "km", "hs", "in", "db", "da", "mir", "msgr", "os", "eslok", "xt", "hz", "ul", "xon",
     "nxon", "mc5i", "chts", "nrrmc", "npc", "ndscr", "ccc", "bce", "hls", "xhpa", "crxm", "daisy",
     "xvpa", "sam", "cpix", "lpix", "OTbs", "OTns", "OTnc", "OTMT", "OTNL", "OTpt", "OTxr"];
 
 #[rustfmt_skip]
-pub static numfnames: &'static[&'static str] = &[ "columns", "init_tabs", "lines",
+pub static numfnames: &[&str] = &[ "columns", "init_tabs", "lines",
     "lines_of_memory", "magic_cookie_glitch", "padding_baud_rate", "virtual_terminal",
     "width_status_line", "num_labels", "label_height", "label_width", "max_attributes",
     "maximum_windows", "max_colors", "max_pairs", "no_color_video", "buffer_capacity",
@@ -40,13 +40,13 @@ pub static numfnames: &'static[&'static str] = &[ "columns", "init_tabs", "lines
     "new_line_delay", "backspace_delay", "horizontal_tab_delay", "number_of_function_keys"];
 
 #[rustfmt_skip]
-pub static numnames: &'static[&'static str] = &[ "cols", "it", "lines", "lm", "xmc", "pb",
+pub static numnames: &[&str] = &[ "cols", "it", "lines", "lm", "xmc", "pb",
     "vt", "wsl", "nlab", "lh", "lw", "ma", "wnum", "colors", "pairs", "ncv", "bufsz", "spinv",
     "spinh", "maddr", "mjump", "mcs", "mls", "npins", "orc", "orl", "orhi", "orvi", "cps", "widcs",
     "btns", "bitwin", "bitype", "UTug", "OTdC", "OTdN", "OTdB", "OTdT", "OTkn"];
 
 #[rustfmt_skip]
-pub static stringfnames: &'static[&'static str] = &[ "back_tab", "bell", "carriage_return",
+pub static stringfnames: &[&str] = &[ "back_tab", "bell", "carriage_return",
     "change_scroll_region", "clear_all_tabs", "clear_screen", "clr_eol", "clr_eos",
     "column_address", "command_character", "cursor_address", "cursor_down", "cursor_home",
     "cursor_invisible", "cursor_left", "cursor_mem_address", "cursor_normal", "cursor_right",
@@ -120,7 +120,7 @@ pub static stringfnames: &'static[&'static str] = &[ "back_tab", "bell", "carria
     "acs_plus", "memory_lock", "memory_unlock", "box_chars_1"];
 
 #[rustfmt_skip]
-pub static stringnames: &'static[&'static str] = &[ "cbt", "_", "cr", "csr", "tbc", "clear",
+pub static stringnames: &[&str] = &[ "cbt", "_", "cr", "csr", "tbc", "clear",
     "_", "_", "hpa", "cmdch", "cup", "cud1", "home", "civis", "cub1", "mrcup", "cnorm", "cuf1",
     "ll", "cuu1", "cvvis", "dch1", "dl1", "dsl", "hd", "smacs", "blink", "bold", "smcup", "smdc",
     "dim", "smir", "invis", "prot", "rev", "smso", "smul", "ech", "rmacs", "sgr0", "rmcup", "rmdc",
@@ -313,7 +313,7 @@ pub fn parse(file: &mut dyn io::Read, longnames: bool) -> Result<TermInfo, Strin
     })
 }
 
-/// Create a dummy TermInfo struct for msys terminals
+/// Creates a dummy TermInfo struct for msys terminals
 pub fn msys_terminfo() -> TermInfo {
     let mut strings = HashMap::new();
     strings.insert("sgr0".to_string(), b"\x1B[0m".to_vec());
diff --git a/src/libterm/terminfo/searcher.rs b/src/libterm/terminfo/searcher.rs
index a9e2626a57e5d..0b17ed36fc8ca 100644
--- a/src/libterm/terminfo/searcher.rs
+++ b/src/libterm/terminfo/searcher.rs
@@ -1,4 +1,4 @@
-//! ncurses-compatible database discovery
+//! ncurses-compatible database discovery.
 //!
 //! Does not support hashed database, only filesystem!
 
diff --git a/src/libterm/win.rs b/src/libterm/win.rs
index 25b03ba59acbc..6d42b01337ed5 100644
--- a/src/libterm/win.rs
+++ b/src/libterm/win.rs
@@ -7,11 +7,11 @@ extern crate libc;
 use std::io;
 use std::io::prelude::*;
 
-use Attr;
-use color;
-use Terminal;
+use crate::Attr;
+use crate::color;
+use crate::Terminal;
 
-/// A Terminal implementation which uses the Win32 Console API.
+/// A Terminal implementation that uses the Win32 Console API.
 pub struct WinConsole<T> {
     buf: T,
     def_foreground: color::Color,
@@ -103,8 +103,7 @@ impl<T: Write + Send + 'static> WinConsole<T> {
         }
     }
 
-    /// Returns `None` whenever the terminal cannot be created for some
-    /// reason.
+    /// Returns `None` whenever the terminal cannot be created for some reason.
     pub fn new(out: T) -> io::Result<WinConsole<T>> {
         let fg;
         let bg;
diff --git a/src/libtest/Cargo.toml b/src/libtest/Cargo.toml
index aade10ed6c324..10bdd6e877c4f 100644
--- a/src/libtest/Cargo.toml
+++ b/src/libtest/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "test"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 name = "test"
diff --git a/src/libtest/formatters/json.rs b/src/libtest/formatters/json.rs
index cc1568265c02e..a06497f98626a 100644
--- a/src/libtest/formatters/json.rs
+++ b/src/libtest/formatters/json.rs
@@ -145,7 +145,7 @@ impl<T: Write> OutputFormatter for JsonFormatter<T> {
 struct EscapedString<S: AsRef<str>>(S);
 
 impl<S: AsRef<str>> ::std::fmt::Display for EscapedString<S> {
-    fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+    fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         let mut start = 0;
 
         for (i, byte) in self.0.as_ref().bytes().enumerate() {
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 2cc80ddea2df4..5c7fb1b804461 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -6,7 +6,7 @@
 //! benchmarks themselves) should be done via the `#[test]` and
 //! `#[bench]` attributes.
 //!
-//! See the [Testing Chapter](../book/first-edition/testing.html) of the book for more details.
+//! See the [Testing Chapter](../book/ch11-00-testing.html) of the book for more details.
 
 // Currently, not much of this is meant for users. It is intended to
 // support the simplest interface possible for representing and
@@ -17,15 +17,13 @@
 // this crate, which relies on this attribute (rather than the value of `--crate-name` passed by
 // cargo) to detect this crate.
 
+#![deny(rust_2018_idioms)]
 #![crate_name = "test"]
 #![unstable(feature = "test", issue = "27812")]
-#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
-       html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
-       html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
+#![doc(html_root_url = "https://doc.rust-lang.org/nightly/", test(attr(deny(warnings))))]
 #![feature(asm)]
-#![cfg_attr(stage0, feature(cfg_target_vendor))]
 #![feature(fnbox)]
-#![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc))]
+#![cfg_attr(any(unix, target_os = "cloudabi"), feature(libc, rustc_private))]
 #![feature(nll)]
 #![feature(set_stdio)]
 #![feature(panic_unwind)]
@@ -33,10 +31,10 @@
 #![feature(termination_trait_lib)]
 #![feature(test)]
 
-extern crate getopts;
+use getopts;
 #[cfg(any(unix, target_os = "cloudabi"))]
 extern crate libc;
-extern crate term;
+use term;
 
 // FIXME(#54291): rustc and/or LLVM don't yet support building with panic-unwind
 //                on aarch64-pc-windows-msvc, so we don't link libtest against
@@ -47,52 +45,57 @@ extern crate term;
 #[cfg(not(all(windows, target_arch = "aarch64")))]
 extern crate panic_unwind;
 
-pub use self::TestFn::*;
 pub use self::ColorConfig::*;
-pub use self::TestResult::*;
-pub use self::TestName::*;
-use self::TestEvent::*;
 use self::NamePadding::*;
 use self::OutputLocation::*;
+use self::TestEvent::*;
+pub use self::TestFn::*;
+pub use self::TestName::*;
+pub use self::TestResult::*;
 
-use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::any::Any;
+use std::borrow::Cow;
 use std::boxed::FnBox;
 use std::cmp;
 use std::collections::BTreeMap;
 use std::env;
 use std::fmt;
 use std::fs::File;
-use std::io::prelude::*;
 use std::io;
+use std::io::prelude::*;
+use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::path::PathBuf;
+use std::process;
 use std::process::Termination;
 use std::sync::mpsc::{channel, Sender};
 use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::{Duration, Instant};
-use std::borrow::Cow;
-use std::process;
 
 const TEST_WARN_TIMEOUT_S: u64 = 60;
 const QUIET_MODE_MAX_COLUMN: usize = 100; // insert a '\n' after 100 tests in quiet mode
 
 // to be used by rustc to compile tests in libtest
 pub mod test {
-    pub use {assert_test_result, filter_tests, parse_opts, run_test, test_main, test_main_static,
-             Bencher, DynTestFn, DynTestName, Metric, MetricMap, Options, RunIgnored, ShouldPanic,
-             StaticBenchFn, StaticTestFn, StaticTestName, TestDesc, TestDescAndFn, TestName,
-             TestOpts, TestResult, TrFailed, TrFailedMsg, TrIgnored, TrOk};
+    pub use crate::{
+        assert_test_result, filter_tests, parse_opts, run_test, test_main, test_main_static,
+        Bencher, DynTestFn, DynTestName, Metric, MetricMap, Options, RunIgnored, ShouldPanic,
+        StaticBenchFn, StaticTestFn, StaticTestName, TestDesc, TestDescAndFn, TestName, TestOpts,
+        TestResult, TrFailed, TrFailedMsg, TrIgnored, TrOk,
+    };
 }
 
-pub mod stats;
 mod formatters;
+pub mod stats;
 
-use formatters::{JsonFormatter, OutputFormatter, PrettyFormatter, TerseFormatter};
+use crate::formatters::{JsonFormatter, OutputFormatter, PrettyFormatter, TerseFormatter};
 
 /// Whether to execute tests concurrently or not
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub enum Concurrent { Yes, No }
+pub enum Concurrent {
+    Yes,
+    No,
+}
 
 // The name of a test. By convention this follows the rules for rust
 // paths; i.e., it should be a series of identifiers separated by double
@@ -132,7 +135,7 @@ impl TestName {
     }
 }
 impl fmt::Display for TestName {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         fmt::Display::fmt(self.as_slice(), f)
     }
 }
@@ -186,7 +189,7 @@ impl TestFn {
 }
 
 impl fmt::Debug for TestFn {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(match *self {
             StaticTestFn(..) => "StaticTestFn(..)",
             StaticBenchFn(..) => "StaticBenchFn(..)",
@@ -325,13 +328,12 @@ pub fn test_main_static(tests: &[&TestDescAndFn]) {
 }
 
 /// Invoked when unit tests terminate. Should panic if the unit
-/// test is considered a failure. By default, invokes `report()`
+/// Tests is considered a failure. By default, invokes `report()`
 /// and checks for a `0` result.
 pub fn assert_test_result<T: Termination>(result: T) {
     let code = result.report();
     assert_eq!(
-        code,
-        0,
+        code, 0,
         "the test returned a termination value with a non-zero status code ({}) \
          which indicates a failure",
         code
@@ -559,14 +561,16 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
     let include_ignored = matches.opt_present("include-ignored");
     if !allow_unstable && include_ignored {
         return Some(Err(
-            "The \"include-ignored\" flag is only accepted on the nightly compiler".into()
+            "The \"include-ignored\" flag is only accepted on the nightly compiler".into(),
         ));
     }
 
     let run_ignored = match (include_ignored, matches.opt_present("ignored")) {
-        (true, true) => return Some(Err(
-            "the options --include-ignored and --ignored are mutually exclusive".into()
-        )),
+        (true, true) => {
+            return Some(Err(
+                "the options --include-ignored and --ignored are mutually exclusive".into(),
+            ));
+        }
         (true, false) => RunIgnored::Yes,
         (false, true) => RunIgnored::Only,
         (false, false) => RunIgnored::No,
@@ -598,7 +602,7 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
                     "argument for --test-threads must be a number > 0 \
                      (error: {})",
                     e
-                )))
+                )));
             }
         },
         None => None,
@@ -614,7 +618,7 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
                 "argument for --color must be auto, always, or never (was \
                  {})",
                 v
-            )))
+            )));
         }
     };
 
@@ -636,7 +640,7 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
                 "argument for --format must be pretty, terse, or json (was \
                  {})",
                 v
-            )))
+            )));
         }
     };
 
@@ -824,7 +828,7 @@ pub fn list_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> io::Res
     let mut nbench = 0;
 
     for test in filter_tests(&opts, tests) {
-        use TestFn::*;
+        use crate::TestFn::*;
 
         let TestDescAndFn {
             desc: TestDesc { name, .. },
@@ -1013,10 +1017,12 @@ fn use_color(opts: &TestOpts) -> bool {
     }
 }
 
-#[cfg(any(target_os = "cloudabi",
-          target_os = "redox",
-          all(target_arch = "wasm32", not(target_os = "emscripten")),
-          all(target_vendor = "fortanix", target_env = "sgx")))]
+#[cfg(any(
+    target_os = "cloudabi",
+    target_os = "redox",
+    all(target_arch = "wasm32", not(target_os = "emscripten")),
+    all(target_vendor = "fortanix", target_env = "sgx")
+))]
 fn stdout_isatty() -> bool {
     // FIXME: Implement isatty on Redox and SGX
     false
@@ -1247,21 +1253,34 @@ fn get_concurrency() -> usize {
         1
     }
 
-    #[cfg(any(all(target_arch = "wasm32", not(target_os = "emscripten")),
-              all(target_vendor = "fortanix", target_env = "sgx")))]
+    #[cfg(any(
+        all(target_arch = "wasm32", not(target_os = "emscripten")),
+        all(target_vendor = "fortanix", target_env = "sgx")
+    ))]
     fn num_cpus() -> usize {
         1
     }
 
-    #[cfg(any(target_os = "android", target_os = "cloudabi", target_os = "emscripten",
-              target_os = "fuchsia", target_os = "ios", target_os = "linux",
-              target_os = "macos", target_os = "solaris"))]
+    #[cfg(any(
+        target_os = "android",
+        target_os = "cloudabi",
+        target_os = "emscripten",
+        target_os = "fuchsia",
+        target_os = "ios",
+        target_os = "linux",
+        target_os = "macos",
+        target_os = "solaris"
+    ))]
     fn num_cpus() -> usize {
         unsafe { libc::sysconf(libc::_SC_NPROCESSORS_ONLN) as usize }
     }
 
-    #[cfg(any(target_os = "freebsd", target_os = "dragonfly", target_os = "bitrig",
-              target_os = "netbsd"))]
+    #[cfg(any(
+        target_os = "freebsd",
+        target_os = "dragonfly",
+        target_os = "bitrig",
+        target_os = "netbsd"
+    ))]
     fn num_cpus() -> usize {
         use std::ptr;
 
@@ -1344,18 +1363,20 @@ pub fn filter_tests(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> Vec<TestDescA
     }
 
     // Skip tests that match any of the skip filters
-    filtered.retain(|test| {
-        !opts.skip.iter().any(|sf| matches_filter(test, sf))
-    });
+    filtered.retain(|test| !opts.skip.iter().any(|sf| matches_filter(test, sf)));
 
     // maybe unignore tests
     match opts.run_ignored {
         RunIgnored::Yes => {
-            filtered.iter_mut().for_each(|test| test.desc.ignore = false);
-        },
+            filtered
+                .iter_mut()
+                .for_each(|test| test.desc.ignore = false);
+        }
         RunIgnored::Only => {
             filtered.retain(|test| test.desc.ignore);
-            filtered.iter_mut().for_each(|test| test.desc.ignore = false);
+            filtered
+                .iter_mut()
+                .for_each(|test| test.desc.ignore = false);
         }
         RunIgnored::No => {}
     }
@@ -1397,7 +1418,8 @@ pub fn run_test(
 ) {
     let TestDescAndFn { desc, testfn } = test;
 
-    let ignore_because_panic_abort = cfg!(target_arch = "wasm32") && !cfg!(target_os = "emscripten")
+    let ignore_because_panic_abort = cfg!(target_arch = "wasm32")
+        && !cfg!(target_os = "emscripten")
         && desc.should_panic != ShouldPanic::No;
 
     if force_ignore || desc.ignore || ignore_because_panic_abort {
@@ -1455,12 +1477,12 @@ pub fn run_test(
 
     match testfn {
         DynBenchFn(bencher) => {
-            ::bench::benchmark(desc, monitor_ch, opts.nocapture, |harness| {
+            crate::bench::benchmark(desc, monitor_ch, opts.nocapture, |harness| {
                 bencher.run(harness)
             });
         }
         StaticBenchFn(benchfn) => {
-            ::bench::benchmark(desc, monitor_ch, opts.nocapture, |harness| {
+            crate::bench::benchmark(desc, monitor_ch, opts.nocapture, |harness| {
                 (benchfn.clone())(harness)
             });
         }
@@ -1488,7 +1510,8 @@ fn calc_result(desc: &TestDesc, task_result: Result<(), Box<dyn Any + Send>>) ->
     match (&desc.should_panic, task_result) {
         (&ShouldPanic::No, Ok(())) | (&ShouldPanic::Yes, Err(_)) => TrOk,
         (&ShouldPanic::YesWithMessage(msg), Err(ref err)) => {
-            if err.downcast_ref::<String>()
+            if err
+                .downcast_ref::<String>()
                 .map(|e| &**e)
                 .or_else(|| err.downcast_ref::<&'static str>().map(|e| *e))
                 .map(|e| e.contains(msg))
@@ -1535,7 +1558,8 @@ impl MetricMap {
     }
 
     pub fn fmt_metrics(&self) -> String {
-        let v = self.0
+        let v = self
+            .0
             .iter()
             .map(|(k, v)| format!("{}: {} (+/- {})", *k, v.value, v.noise))
             .collect::<Vec<_>>();
@@ -1644,7 +1668,8 @@ where
 
         // If we've run for 100ms and seem to have converged to a
         // stable median.
-        if loop_run > Duration::from_millis(100) && summ.median_abs_dev_pct < 1.0
+        if loop_run > Duration::from_millis(100)
+            && summ.median_abs_dev_pct < 1.0
             && summ.median - summ5.median < summ5.median_abs_dev
         {
             return summ5;
@@ -1670,12 +1695,12 @@ where
 }
 
 pub mod bench {
-    use std::panic::{catch_unwind, AssertUnwindSafe};
+    use super::{BenchMode, BenchSamples, Bencher, MonitorMsg, Sender, Sink, TestDesc, TestResult};
+    use crate::stats;
     use std::cmp;
     use std::io;
+    use std::panic::{catch_unwind, AssertUnwindSafe};
     use std::sync::{Arc, Mutex};
-    use stats;
-    use super::{BenchMode, BenchSamples, Bencher, MonitorMsg, Sender, Sink, TestDesc, TestResult};
 
     pub fn benchmark<F>(desc: TestDesc, monitor_ch: Sender<MonitorMsg>, nocapture: bool, f: F)
     where
@@ -1750,14 +1775,15 @@ pub mod bench {
 
 #[cfg(test)]
 mod tests {
-    use test::{filter_tests, parse_opts, run_test, DynTestFn, DynTestName, MetricMap, RunIgnored,
-               ShouldPanic, StaticTestName, TestDesc, TestDescAndFn, TestOpts, TrFailed,
-               TrFailedMsg, TrIgnored, TrOk};
+    use crate::bench;
+    use crate::test::{
+        filter_tests, parse_opts, run_test, DynTestFn, DynTestName, MetricMap, RunIgnored,
+        ShouldPanic, StaticTestName, TestDesc, TestDescAndFn, TestOpts, TrFailed, TrFailedMsg,
+        TrIgnored, TrOk,
+    };
+    use crate::Bencher;
+    use crate::Concurrent;
     use std::sync::mpsc::channel;
-    use bench;
-    use Bencher;
-    use Concurrent;
-
 
     fn one_ignored_one_unignored_test() -> Vec<TestDescAndFn> {
         vec![
@@ -2157,7 +2183,7 @@ mod tests {
             allow_fail: false,
         };
 
-        ::bench::benchmark(desc, tx, true, f);
+        crate::bench::benchmark(desc, tx, true, f);
         rx.recv().unwrap();
     }
 
@@ -2176,7 +2202,7 @@ mod tests {
             allow_fail: false,
         };
 
-        ::bench::benchmark(desc, tx, true, f);
+        crate::bench::benchmark(desc, tx, true, f);
         rx.recv().unwrap();
     }
 }
diff --git a/src/libtest/stats.rs b/src/libtest/stats.rs
index 9fc5f09ba6c92..5c9421d5ea4b0 100644
--- a/src/libtest/stats.rs
+++ b/src/libtest/stats.rs
@@ -319,8 +319,8 @@ pub fn winsorize(samples: &mut [f64], pct: f64) {
 
 #[cfg(test)]
 mod tests {
-    use stats::Stats;
-    use stats::Summary;
+    use crate::stats::Stats;
+    use crate::stats::Summary;
     use std::f64;
     use std::io::prelude::*;
     use std::io;
@@ -899,7 +899,7 @@ mod tests {
 mod bench {
     extern crate test;
     use self::test::Bencher;
-    use stats::Stats;
+    use crate::stats::Stats;
 
     #[bench]
     pub fn sum_three_items(b: &mut Bencher) {
diff --git a/src/libunwind/Cargo.toml b/src/libunwind/Cargo.toml
index 2577d6dd31d8f..2378b0a315a16 100644
--- a/src/libunwind/Cargo.toml
+++ b/src/libunwind/Cargo.toml
@@ -3,6 +3,7 @@ authors = ["The Rust Project Developers"]
 name = "unwind"
 version = "0.0.0"
 build = "build.rs"
+edition = "2018"
 
 [lib]
 name = "unwind"
diff --git a/src/libunwind/lib.rs b/src/libunwind/lib.rs
index 7ed7837268dcd..0ccffea317053 100644
--- a/src/libunwind/lib.rs
+++ b/src/libunwind/lib.rs
@@ -1,7 +1,8 @@
 #![no_std]
 #![unstable(feature = "panic_unwind", issue = "32837")]
 
-#![cfg_attr(stage0, feature(cfg_target_vendor))]
+#![deny(rust_2018_idioms)]
+
 #![feature(link_cfg)]
 #![feature(nll)]
 #![feature(staged_api)]
@@ -19,7 +20,6 @@ cfg_if! {
     } else if #[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))] {
         // no unwinder on the system!
     } else {
-        extern crate libc;
         mod libunwind;
         pub use libunwind::*;
     }
diff --git a/src/libunwind/libunwind.rs b/src/libunwind/libunwind.rs
index 31e806c8fb656..339b554ed6abd 100644
--- a/src/libunwind/libunwind.rs
+++ b/src/libunwind/libunwind.rs
@@ -21,7 +21,7 @@ pub enum _Unwind_Reason_Code {
     _URC_CONTINUE_UNWIND = 8,
     _URC_FAILURE = 9, // used only by ARM EHABI
 }
-pub use self::_Unwind_Reason_Code::*;
+pub use _Unwind_Reason_Code::*;
 
 pub type _Unwind_Exception_Class = u64;
 pub type _Unwind_Word = uintptr_t;
@@ -94,7 +94,7 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
         _UA_FORCE_UNWIND = 8,
         _UA_END_OF_STACK = 16,
     }
-    pub use self::_Unwind_Action::*;
+    pub use _Unwind_Action::*;
 
     extern "C" {
         pub fn _Unwind_GetGR(ctx: *mut _Unwind_Context, reg_index: c_int) -> _Unwind_Word;
@@ -118,7 +118,7 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
         _US_FORCE_UNWIND = 8,
         _US_END_OF_STACK = 16,
     }
-    pub use self::_Unwind_State::*;
+    pub use _Unwind_State::*;
 
     #[repr(C)]
     enum _Unwind_VRS_Result {
@@ -134,7 +134,7 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
         _UVRSC_WMMXD = 3,
         _UVRSC_WMMXC = 4,
     }
-    use self::_Unwind_VRS_RegClass::*;
+    use _Unwind_VRS_RegClass::*;
     #[repr(C)]
     enum _Unwind_VRS_DataRepresentation {
         _UVRSD_UINT32 = 0,
@@ -144,7 +144,7 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
         _UVRSD_FLOAT = 4,
         _UVRSD_DOUBLE = 5,
     }
-    use self::_Unwind_VRS_DataRepresentation::*;
+    use _Unwind_VRS_DataRepresentation::*;
 
     pub const UNWIND_POINTER_REG: c_int = 12;
     pub const UNWIND_IP_REG: c_int = 15;
diff --git a/src/llvm b/src/llvm
deleted file mode 160000
index f4728ed8fa229..0000000000000
--- a/src/llvm
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit f4728ed8fa2296c5b009bb85550e157e1e57ed0b
diff --git a/src/llvm-project b/src/llvm-project
new file mode 160000
index 0000000000000..73a75d35b9776
--- /dev/null
+++ b/src/llvm-project
@@ -0,0 +1 @@
+Subproject commit 73a75d35b9776d56160fa3200aca4a970ae49b60
diff --git a/src/rustllvm/PassWrapper.cpp b/src/rustllvm/PassWrapper.cpp
index df7a81643bcb6..25595e14982ae 100644
--- a/src/rustllvm/PassWrapper.cpp
+++ b/src/rustllvm/PassWrapper.cpp
@@ -789,7 +789,7 @@ struct LLVMRustThinLTOData {
   StringMap<GVSummaryMapTy> ModuleToDefinedGVSummaries;
 
 #if LLVM_VERSION_GE(7, 0)
-  LLVMRustThinLTOData() : Index(/* isPerformingAnalysis = */ false) {}
+  LLVMRustThinLTOData() : Index(/* HaveGVs = */ false) {}
 #endif
 };
 
@@ -865,7 +865,12 @@ LLVMRustCreateThinLTOData(LLVMRustThinLTOModule *modules,
   auto deadIsPrevailing = [&](GlobalValue::GUID G) {
     return PrevailingType::Unknown;
   };
+#if LLVM_VERSION_GE(8, 0)
+  computeDeadSymbolsWithConstProp(Ret->Index, Ret->GUIDPreservedSymbols,
+                                  deadIsPrevailing, /* ImportEnabled = */ true);
+#else
   computeDeadSymbols(Ret->Index, Ret->GUIDPreservedSymbols, deadIsPrevailing);
+#endif
 #else
   computeDeadSymbols(Ret->Index, Ret->GUIDPreservedSymbols);
 #endif
@@ -1087,10 +1092,10 @@ LLVMRustThinLTOBufferLen(const LLVMRustThinLTOBuffer *Buffer) {
 // processing.  We'll call this once per module optimized through ThinLTO, and
 // it'll be called concurrently on many threads.
 extern "C" LLVMModuleRef
-LLVMRustParseBitcodeForThinLTO(LLVMContextRef Context,
-                               const char *data,
-                               size_t len,
-                               const char *identifier) {
+LLVMRustParseBitcodeForLTO(LLVMContextRef Context,
+                           const char *data,
+                           size_t len,
+                           const char *identifier) {
   StringRef Data(data, len);
   MemoryBufferRef Buffer(Data, identifier);
   unwrap(Context)->enableDebugTypeODRUniquing();
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 9d3e6f93b0c11..b33165b846339 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -188,6 +188,8 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
     return Attribute::SanitizeMemory;
   case NonLazyBind:
     return Attribute::NonLazyBind;
+  case OptimizeNone:
+    return Attribute::OptimizeNone;
   }
   report_fatal_error("bad AttributeKind");
 }
@@ -294,7 +296,7 @@ extern "C" void LLVMRustSetHasUnsafeAlgebra(LLVMValueRef V) {
 extern "C" LLVMValueRef
 LLVMRustBuildAtomicLoad(LLVMBuilderRef B, LLVMValueRef Source, const char *Name,
                         LLVMAtomicOrdering Order) {
-  LoadInst *LI = new LoadInst(unwrap(Source), 0);
+  LoadInst *LI = new LoadInst(unwrap(Source));
   LI->setAtomic(fromRust(Order));
   return wrap(unwrap(B)->Insert(LI, Name));
 }
@@ -511,6 +513,90 @@ static DINode::DIFlags fromRust(LLVMRustDIFlags Flags) {
   return Result;
 }
 
+// These values **must** match debuginfo::DISPFlags! They also *happen*
+// to match LLVM, but that isn't required as we do giant sets of
+// matching below. The value shouldn't be directly passed to LLVM.
+enum class LLVMRustDISPFlags : uint32_t {
+  SPFlagZero = 0,
+  SPFlagVirtual = 1,
+  SPFlagPureVirtual = 2,
+  SPFlagLocalToUnit = (1 << 2),
+  SPFlagDefinition = (1 << 3),
+  SPFlagOptimized = (1 << 4),
+  // Do not add values that are not supported by the minimum LLVM
+  // version we support! see llvm/include/llvm/IR/DebugInfoFlags.def
+  // (In LLVM < 8, createFunction supported these as separate bool arguments.)
+};
+
+inline LLVMRustDISPFlags operator&(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) &
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDISPFlags operator|(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) |
+                                      static_cast<uint32_t>(B));
+}
+
+inline LLVMRustDISPFlags &operator|=(LLVMRustDISPFlags &A, LLVMRustDISPFlags B) {
+  return A = A | B;
+}
+
+inline bool isSet(LLVMRustDISPFlags F) { return F != LLVMRustDISPFlags::SPFlagZero; }
+
+inline LLVMRustDISPFlags virtuality(LLVMRustDISPFlags F) {
+  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(F) & 0x3);
+}
+
+#if LLVM_VERSION_GE(8, 0)
+static DISubprogram::DISPFlags fromRust(LLVMRustDISPFlags SPFlags) {
+  DISubprogram::DISPFlags Result = DISubprogram::DISPFlags::SPFlagZero;
+
+  switch (virtuality(SPFlags)) {
+  case LLVMRustDISPFlags::SPFlagVirtual:
+    Result |= DISubprogram::DISPFlags::SPFlagVirtual;
+    break;
+  case LLVMRustDISPFlags::SPFlagPureVirtual:
+    Result |= DISubprogram::DISPFlags::SPFlagPureVirtual;
+    break;
+  default:
+    // The rest are handled below
+    break;
+  }
+
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagLocalToUnit)) {
+    Result |= DISubprogram::DISPFlags::SPFlagLocalToUnit;
+  }
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagDefinition)) {
+    Result |= DISubprogram::DISPFlags::SPFlagDefinition;
+  }
+  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagOptimized)) {
+    Result |= DISubprogram::DISPFlags::SPFlagOptimized;
+  }
+
+  return Result;
+}
+#endif
+
+enum class LLVMRustDebugEmissionKind {
+  NoDebug,
+  FullDebug,
+  LineTablesOnly,
+};
+
+static DICompileUnit::DebugEmissionKind fromRust(LLVMRustDebugEmissionKind Kind) {
+  switch (Kind) {
+  case LLVMRustDebugEmissionKind::NoDebug:
+    return DICompileUnit::DebugEmissionKind::NoDebug;
+  case LLVMRustDebugEmissionKind::FullDebug:
+    return DICompileUnit::DebugEmissionKind::FullDebug;
+  case LLVMRustDebugEmissionKind::LineTablesOnly:
+    return DICompileUnit::DebugEmissionKind::LineTablesOnly;
+  default:
+    report_fatal_error("bad DebugEmissionKind.");
+  }
+}
+
 extern "C" uint32_t LLVMRustDebugMetadataVersion() {
   return DEBUG_METADATA_VERSION;
 }
@@ -551,11 +637,13 @@ extern "C" void LLVMRustDIBuilderFinalize(LLVMRustDIBuilderRef Builder) {
 extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateCompileUnit(
     LLVMRustDIBuilderRef Builder, unsigned Lang, LLVMMetadataRef FileRef,
     const char *Producer, bool isOptimized, const char *Flags,
-    unsigned RuntimeVer, const char *SplitName) {
+    unsigned RuntimeVer, const char *SplitName,
+    LLVMRustDebugEmissionKind Kind) {
   auto *File = unwrapDI<DIFile>(FileRef);
 
   return wrap(Builder->createCompileUnit(Lang, File, Producer, isOptimized,
-                                         Flags, RuntimeVer, SplitName));
+                                         Flags, RuntimeVer, SplitName,
+                                         fromRust(Kind)));
 }
 
 extern "C" LLVMMetadataRef
@@ -575,16 +663,26 @@ LLVMRustDIBuilderCreateSubroutineType(LLVMRustDIBuilderRef Builder,
 extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFunction(
     LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
     const char *LinkageName, LLVMMetadataRef File, unsigned LineNo,
-    LLVMMetadataRef Ty, bool IsLocalToUnit, bool IsDefinition,
-    unsigned ScopeLine, LLVMRustDIFlags Flags, bool IsOptimized,
-    LLVMValueRef Fn, LLVMMetadataRef TParam, LLVMMetadataRef Decl) {
+    LLVMMetadataRef Ty, unsigned ScopeLine, LLVMRustDIFlags Flags,
+    LLVMRustDISPFlags SPFlags, LLVMValueRef Fn, LLVMMetadataRef TParam,
+    LLVMMetadataRef Decl) {
   DITemplateParameterArray TParams =
       DITemplateParameterArray(unwrap<MDTuple>(TParam));
+#if LLVM_VERSION_GE(8, 0)
+  DISubprogram *Sub = Builder->createFunction(
+      unwrapDI<DIScope>(Scope), Name, LinkageName, unwrapDI<DIFile>(File),
+      LineNo, unwrapDI<DISubroutineType>(Ty), ScopeLine, fromRust(Flags),
+      fromRust(SPFlags), TParams, unwrapDIPtr<DISubprogram>(Decl));
+#else
+  bool IsLocalToUnit = isSet(SPFlags & LLVMRustDISPFlags::SPFlagLocalToUnit);
+  bool IsDefinition = isSet(SPFlags & LLVMRustDISPFlags::SPFlagDefinition);
+  bool IsOptimized = isSet(SPFlags & LLVMRustDISPFlags::SPFlagOptimized);
   DISubprogram *Sub = Builder->createFunction(
       unwrapDI<DIScope>(Scope), Name, LinkageName, unwrapDI<DIFile>(File),
       LineNo, unwrapDI<DISubroutineType>(Ty), IsLocalToUnit, IsDefinition,
       ScopeLine, fromRust(Flags), IsOptimized, TParams,
       unwrapDIPtr<DISubprogram>(Decl));
+#endif
   unwrap<Function>(Fn)->setSubprogram(Sub);
   return wrap(Sub);
 }
@@ -773,14 +871,14 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerationType(
     LLVMRustDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
     LLVMMetadataRef File, unsigned LineNumber, uint64_t SizeInBits,
     uint32_t AlignInBits, LLVMMetadataRef Elements,
-    LLVMMetadataRef ClassTy, bool IsFixed) {
+    LLVMMetadataRef ClassTy, bool IsScoped) {
 #if LLVM_VERSION_GE(7, 0)
   return wrap(Builder->createEnumerationType(
       unwrapDI<DIDescriptor>(Scope), Name, unwrapDI<DIFile>(File), LineNumber,
       SizeInBits, AlignInBits, DINodeArray(unwrapDI<MDTuple>(Elements)),
-      unwrapDI<DIType>(ClassTy), "", IsFixed));
+      unwrapDI<DIType>(ClassTy), "", IsScoped));
 #else
-  // Ignore IsFixed on older LLVM.
+  // Ignore IsScoped on older LLVM.
   return wrap(Builder->createEnumerationType(
       unwrapDI<DIDescriptor>(Scope), Name, unwrapDI<DIFile>(File), LineNumber,
       SizeInBits, AlignInBits, DINodeArray(unwrapDI<MDTuple>(Elements)),
@@ -920,7 +1018,11 @@ extern "C" void LLVMRustUnpackOptimizationDiagnostic(
   if (loc.isValid()) {
     *Line = loc.getLine();
     *Column = loc.getColumn();
+#if LLVM_VERSION_GE(8, 0)
+    FilenameOS << loc.getAbsolutePath();
+#else
     FilenameOS << loc.getFilename();
+#endif
   }
 
   RawRustStringOstream MessageOS(MessageOut);
diff --git a/src/rustllvm/llvm-rebuild-trigger b/src/rustllvm/llvm-rebuild-trigger
index a268838de4515..9ee1bceb632bd 100644
--- a/src/rustllvm/llvm-rebuild-trigger
+++ b/src/rustllvm/llvm-rebuild-trigger
@@ -1,4 +1,4 @@
 # If this file is modified, then llvm will be (optionally) cleaned and then rebuilt.
 # The actual contents of this file do not matter, but to trigger a change on the
 # build bots then the contents should be changed so git updates the mtime.
-2018-12-13
+2019-01-16
diff --git a/src/rustllvm/rustllvm.h b/src/rustllvm/rustllvm.h
index 1ed281e8b1be1..933266b402526 100644
--- a/src/rustllvm/rustllvm.h
+++ b/src/rustllvm/rustllvm.h
@@ -84,6 +84,7 @@ enum LLVMRustAttribute {
   SanitizeAddress = 21,
   SanitizeMemory = 22,
   NonLazyBind = 23,
+  OptimizeNone = 24,
 };
 
 typedef struct OpaqueRustString *RustStringRef;
diff --git a/src/stage0.txt b/src/stage0.txt
index 2e376ed1cede5..a93ee6bc604a4 100644
--- a/src/stage0.txt
+++ b/src/stage0.txt
@@ -12,7 +12,7 @@
 # source tarball for a stable release you'll likely see `1.x.0` for rustc and
 # `0.x.0` for Cargo where they were released on `date`.
 
-date: 2019-01-04
+date: 2019-02-17
 rustc: beta
 cargo: beta
 
diff --git a/src/stdsimd b/src/stdsimd
index 269d0ba959f70..359845eb7cae8 160000
--- a/src/stdsimd
+++ b/src/stdsimd
@@ -1 +1 @@
-Subproject commit 269d0ba959f70e9b692e528311c78b8f9601d4af
+Subproject commit 359845eb7cae85799dc2ec81f2fb05da0aa6276d
diff --git a/src/test/codegen/align-enum.rs b/src/test/codegen/align-enum.rs
new file mode 100644
index 0000000000000..2251c54229ee0
--- /dev/null
+++ b/src/test/codegen/align-enum.rs
@@ -0,0 +1,36 @@
+// compile-flags: -C no-prepopulate-passes
+// ignore-tidy-linelength
+// min-llvm-version 7.0
+
+#![crate_type = "lib"]
+#![feature(repr_align_enum)]
+
+#[repr(align(64))]
+pub enum Align64 {
+    A(u32),
+    B(u32),
+}
+// CHECK: %Align64 = type { [0 x i32], i32, [15 x i32] }
+
+pub struct Nested64 {
+    a: u8,
+    b: Align64,
+    c: u16,
+}
+
+// CHECK-LABEL: @align64
+#[no_mangle]
+pub fn align64(a: u32) -> Align64 {
+// CHECK: %a64 = alloca %Align64, align 64
+// CHECK: call void @llvm.memcpy.{{.*}}(i8* align 64 %{{.*}}, i8* align 64 %{{.*}}, i{{[0-9]+}} 64, i1 false)
+    let a64 = Align64::A(a);
+    a64
+}
+
+// CHECK-LABEL: @nested64
+#[no_mangle]
+pub fn nested64(a: u8, b: u32, c: u16) -> Nested64 {
+// CHECK: %n64 = alloca %Nested64, align 64
+    let n64 = Nested64 { a, b: Align64::B(b), c };
+    n64
+}
diff --git a/src/test/codegen/box-maybe-uninit.rs b/src/test/codegen/box-maybe-uninit.rs
index a7fb74c04731d..ad1d259a0da21 100644
--- a/src/test/codegen/box-maybe-uninit.rs
+++ b/src/test/codegen/box-maybe-uninit.rs
@@ -9,5 +9,8 @@ use std::mem::MaybeUninit;
 pub fn box_uninitialized() -> Box<MaybeUninit<usize>> {
     // CHECK-LABEL: @box_uninitialized
     // CHECK-NOT: store
+    // CHECK-NOT: alloca
+    // CHECK-NOT: memcpy
+    // CHECK-NOT: memset
     Box::new(MaybeUninit::uninitialized())
 }
diff --git a/src/test/codegen/enum-debug-clike.rs b/src/test/codegen/enum-debug-clike.rs
index 98f07505f7539..62cfef5a845e9 100644
--- a/src/test/codegen/enum-debug-clike.rs
+++ b/src/test/codegen/enum-debug-clike.rs
@@ -8,8 +8,11 @@
 
 // compile-flags: -g -C no-prepopulate-passes
 
+// DIFlagFixedEnum was deprecated in 8.0, renamed to DIFlagEnumClass.
+// We match either for compatibility.
+
 // CHECK-LABEL: @main
-// CHECK: {{.*}}DICompositeType{{.*}}tag: DW_TAG_enumeration_type,{{.*}}name: "E",{{.*}}flags: DIFlagFixedEnum,{{.*}}
+// CHECK: {{.*}}DICompositeType{{.*}}tag: DW_TAG_enumeration_type,{{.*}}name: "E",{{.*}}flags: {{(DIFlagEnumClass|DIFlagFixedEnum)}},{{.*}}
 // CHECK: {{.*}}DIEnumerator{{.*}}name: "A",{{.*}}value: {{[0-9].*}}
 // CHECK: {{.*}}DIEnumerator{{.*}}name: "B",{{.*}}value: {{[0-9].*}}
 // CHECK: {{.*}}DIEnumerator{{.*}}name: "C",{{.*}}value: {{[0-9].*}}
diff --git a/src/test/codegen/inline-always-works-always.rs b/src/test/codegen/inline-always-works-always.rs
new file mode 100644
index 0000000000000..912af782a8f36
--- /dev/null
+++ b/src/test/codegen/inline-always-works-always.rs
@@ -0,0 +1,21 @@
+// revisions: NO-OPT SIZE-OPT SPEED-OPT
+//[NO-OPT] compile-flags: -Copt-level=0
+//[SIZE-OPT] compile-flags: -Copt-level=s
+//[SPEED-OPT] compile-flags: -Copt-level=3
+
+#![crate_type="rlib"]
+
+#[no_mangle]
+#[inline(always)]
+pub extern "C" fn callee() -> u32 {
+    4 + 4
+}
+
+// CHECK-LABEL: caller
+// SIZE-OPT: ret i32 8
+// SPEED-OPT: ret i32 8
+// NO-OPT: ret i32 8
+#[no_mangle]
+pub extern "C" fn caller() -> u32 {
+    callee()
+}
diff --git a/src/test/codegen/no-dllimport-w-cross-lang-lto.rs b/src/test/codegen/no-dllimport-w-cross-lang-lto.rs
index c1c1ef6ede2cb..33fc2bc1540d3 100644
--- a/src/test/codegen/no-dllimport-w-cross-lang-lto.rs
+++ b/src/test/codegen/no-dllimport-w-cross-lang-lto.rs
@@ -3,7 +3,7 @@
 
 // no-prefer-dynamic
 // only-msvc
-// compile-flags: -Z cross-lang-lto
+// compile-flags: -C linker-plugin-lto
 
 #![crate_type = "rlib"]
 
diff --git a/src/test/codegen/optimize-attr-1.rs b/src/test/codegen/optimize-attr-1.rs
new file mode 100644
index 0000000000000..376447e5b5db0
--- /dev/null
+++ b/src/test/codegen/optimize-attr-1.rs
@@ -0,0 +1,50 @@
+// revisions: NO-OPT SIZE-OPT SPEED-OPT
+//[NO-OPT] compile-flags: -Copt-level=0 -Ccodegen-units=1
+//[SIZE-OPT] compile-flags: -Copt-level=s -Ccodegen-units=1
+//[SPEED-OPT] compile-flags: -Copt-level=3 -Ccodegen-units=1
+
+#![feature(optimize_attribute)]
+#![crate_type="rlib"]
+
+// CHECK-LABEL: define i32 @nothing
+// CHECK-SAME: [[NOTHING_ATTRS:#[0-9]+]]
+// NO-OPT: ret i32 %1
+// SIZE-OPT: ret i32 4
+// SPEEC-OPT: ret i32 4
+#[no_mangle]
+pub fn nothing() -> i32 {
+    2 + 2
+}
+
+// CHECK-LABEL: define i32 @size
+// CHECK-SAME: [[SIZE_ATTRS:#[0-9]+]]
+// NO-OPT: ret i32 %1
+// SIZE-OPT: ret i32 6
+// SPEED-OPT: ret i32 6
+#[optimize(size)]
+#[no_mangle]
+pub fn size() -> i32 {
+    3 + 3
+}
+
+// CHECK-LABEL: define i32 @speed
+// NO-OPT-SAME: [[NOTHING_ATTRS]]
+// SPEED-OPT-SAME: [[NOTHING_ATTRS]]
+// SIZE-OPT-SAME: [[SPEED_ATTRS:#[0-9]+]]
+// NO-OPT: ret i32 %1
+// SIZE-OPT: ret i32 8
+// SPEED-OPT: ret i32 8
+#[optimize(speed)]
+#[no_mangle]
+pub fn speed() -> i32 {
+    4 + 4
+}
+
+// NO-OPT-DAG: attributes [[SIZE_ATTRS]] = {{.*}}minsize{{.*}}optsize{{.*}}
+// SPEED-OPT-DAG: attributes [[SIZE_ATTRS]] = {{.*}}minsize{{.*}}optsize{{.*}}
+// SIZE-OPT-DAG: attributes [[NOTHING_ATTRS]] = {{.*}}optsize{{.*}}
+// SIZE-OPT-DAG: attributes [[SIZE_ATTRS]] = {{.*}}minsize{{.*}}optsize{{.*}}
+
+// SIZE-OPT: attributes [[SPEED_ATTRS]]
+// SIZE-OPT-NOT: minsize
+// SIZE-OPT-NOT: optsize
diff --git a/src/test/codegen/simd-intrinsic-generic-bitmask.rs b/src/test/codegen/simd-intrinsic-generic-bitmask.rs
new file mode 100644
index 0000000000000..cd8130f923148
--- /dev/null
+++ b/src/test/codegen/simd-intrinsic-generic-bitmask.rs
@@ -0,0 +1,57 @@
+// compile-flags: -C no-prepopulate-passes
+// ignore-tidy-linelength
+
+#![crate_type = "lib"]
+
+#![feature(repr_simd, platform_intrinsics)]
+#![allow(non_camel_case_types)]
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct u32x2(u32, u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct i32x2(i32, i32);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct i8x16(
+    i8, i8, i8, i8, i8, i8, i8, i8,
+    i8, i8, i8, i8, i8, i8, i8, i8,
+);
+
+
+extern "platform-intrinsic" {
+    fn simd_bitmask<T, U>(x: T) -> U;
+}
+
+// CHECK-LABEL: @bitmask_int
+#[no_mangle]
+pub unsafe fn bitmask_int(x: i32x2) -> u8 {
+    // CHECK: [[A:%[0-9]+]] = lshr <2 x i32> %{{[0-9]+}}, <i32 31, i32 31>
+    // CHECK: [[B:%[0-9]+]] = trunc <2 x i32> [[A]] to <2 x i1>
+    // CHECK: [[C:%[0-9]+]] = bitcast <2 x i1> [[B]] to i2
+    // CHECK: %{{[0-9]+}} = zext i2 [[C]] to i8
+    simd_bitmask(x)
+}
+
+// CHECK-LABEL: @bitmask_uint
+#[no_mangle]
+pub unsafe fn bitmask_uint(x: u32x2) -> u8 {
+    // CHECK: [[A:%[0-9]+]] = lshr <2 x i32> %{{[0-9]+}}, <i32 31, i32 31>
+    // CHECK: [[B:%[0-9]+]] = trunc <2 x i32> [[A]] to <2 x i1>
+    // CHECK: [[C:%[0-9]+]] = bitcast <2 x i1> [[B]] to i2
+    // CHECK: %{{[0-9]+}} = zext i2 [[C]] to i8
+    simd_bitmask(x)
+}
+
+// CHECK-LABEL: @bitmask_int16
+#[no_mangle]
+pub unsafe fn bitmask_int16(x: i8x16) -> u16 {
+    // CHECK: [[A:%[0-9]+]] = lshr <16 x i8> %{{[0-9]+}}, <i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7, i8 7>
+    // CHECK: [[B:%[0-9]+]] = trunc <16 x i8> [[A]] to <16 x i1>
+    // CHECK: %{{[0-9]+}} = bitcast <16 x i1> [[B]] to i16
+    // CHECK-NOT: zext
+    simd_bitmask(x)
+}
diff --git a/src/test/codegen/target-cpu-on-functions.rs b/src/test/codegen/target-cpu-on-functions.rs
index 5692dca1df5a2..3fdf6ab6d002f 100644
--- a/src/test/codegen/target-cpu-on-functions.rs
+++ b/src/test/codegen/target-cpu-on-functions.rs
@@ -3,7 +3,7 @@
 
 // no-prefer-dynamic
 // ignore-tidy-linelength
-// compile-flags: -C no-prepopulate-passes -C panic=abort -Z cross-lang-lto -Cpasses=name-anon-globals
+// compile-flags: -C no-prepopulate-passes -C panic=abort -C linker-plugin-lto -Cpasses=name-anon-globals
 
 #![crate_type = "staticlib"]
 
diff --git a/src/test/compile-fail-fulldeps/auxiliary/lint_group_plugin_test.rs b/src/test/compile-fail-fulldeps/auxiliary/lint_group_plugin_test.rs
index bca1d7a72b4ab..16630e2b31285 100644
--- a/src/test/compile-fail-fulldeps/auxiliary/lint_group_plugin_test.rs
+++ b/src/test/compile-fail-fulldeps/auxiliary/lint_group_plugin_test.rs
@@ -19,6 +19,10 @@ declare_lint!(PLEASE_LINT, Warn, "Warn about items named 'pleaselintme'");
 struct Pass;
 
 impl LintPass for Pass {
+    fn name(&self) -> &'static str {
+        "Pass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TEST_LINT, PLEASE_LINT)
     }
diff --git a/src/test/compile-fail/must_use-in-stdlib-traits.rs b/src/test/compile-fail/must_use-in-stdlib-traits.rs
index 7e446fdaeaf41..b4f07ab33214c 100644
--- a/src/test/compile-fail/must_use-in-stdlib-traits.rs
+++ b/src/test/compile-fail/must_use-in-stdlib-traits.rs
@@ -4,7 +4,7 @@
 use std::iter::Iterator;
 use std::future::Future;
 
-use std::task::{Poll, LocalWaker};
+use std::task::{Poll, Waker};
 use std::pin::Pin;
 use std::unimplemented;
 
@@ -13,7 +13,7 @@ struct MyFuture;
 impl Future for MyFuture {
    type Output = u32;
 
-   fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<u32> {
+   fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<u32> {
       Poll::Pending
    }
 }
diff --git a/src/test/debuginfo/generators.rs b/src/test/debuginfo/generators.rs
new file mode 100644
index 0000000000000..b56d222e0e01e
--- /dev/null
+++ b/src/test/debuginfo/generators.rs
@@ -0,0 +1,36 @@
+// min-lldb-version: 310
+
+// compile-flags:-g
+
+// === GDB TESTS ===================================================================================
+
+// gdb-command:run
+// gdb-command:print a
+// gdb-check:$1 = 5
+
+// === LLDB TESTS ==================================================================================
+
+// lldb-command:run
+// lldb-command:print a
+// lldbg-check:(int) $0 = 5
+// lldbr-check:(int) a = 5
+
+#![feature(omit_gdb_pretty_printer_section, generators, generator_trait, pin)]
+#![omit_gdb_pretty_printer_section]
+
+use std::ops::Generator;
+use std::pin::Pin;
+
+fn main() {
+    let mut a = 5;
+    let mut b = || {
+        yield;
+        _zzz(); // #break
+        a = 6;
+    };
+    Pin::new(&mut b).resume();
+    Pin::new(&mut b).resume();
+    _zzz(); // #break
+}
+
+fn _zzz() {()}
diff --git a/src/test/incremental/change_add_field/struct_point.rs b/src/test/incremental/change_add_field/struct_point.rs
index 6006831e48234..182e6cb45be64 100644
--- a/src/test/incremental/change_add_field/struct_point.rs
+++ b/src/test/incremental/change_add_field/struct_point.rs
@@ -60,7 +60,7 @@ pub mod point {
     }
 }
 
-/// A fn that has the changed type in its signature; must currently be
+/// A function that has the changed type in its signature; must currently be
 /// rebuilt.
 ///
 /// You could imagine that, in the future, if the change were
@@ -76,7 +76,7 @@ pub mod fn_with_type_in_sig {
     }
 }
 
-/// Call a fn that has the changed type in its signature; this
+/// Call a function that has the changed type in its signature; this
 /// currently must also be rebuilt.
 ///
 /// You could imagine that, in the future, if the change were
@@ -92,7 +92,7 @@ pub mod call_fn_with_type_in_sig {
     }
 }
 
-/// A fn that uses the changed type, but only in its body, not its
+/// A function that uses the changed type, but only in its body, not its
 /// signature.
 ///
 /// You could imagine that, in the future, if the change were
@@ -108,10 +108,10 @@ pub mod fn_with_type_in_body {
     }
 }
 
-/// A fn X that calls a fn Y, where Y uses the changed type in its
+/// A function `X` that calls a function `Y`, where `Y` uses the changed type in its
 /// body. In this case, the effects of the change should be contained
-/// to Y; X should not have to be rebuilt, nor should it need to be
-/// typechecked again.
+/// to `Y`; `X` should not have to be rebuilt, nor should it need to be
+/// type-checked again.
 pub mod call_fn_with_type_in_body {
     use fn_with_type_in_body;
 
@@ -121,7 +121,7 @@ pub mod call_fn_with_type_in_body {
     }
 }
 
-/// A fn item that makes an instance of `Point` but does not invoke methods
+/// A function item that makes an instance of `Point` but does not invoke methods.
 pub mod fn_make_struct {
     use point::Point;
 
@@ -131,7 +131,7 @@ pub mod fn_make_struct {
     }
 }
 
-/// A fn item that reads fields from `Point` but does not invoke methods
+/// A function item that reads fields from `Point` but does not invoke methods.
 pub mod fn_read_field {
     use point::Point;
 
@@ -141,7 +141,7 @@ pub mod fn_read_field {
     }
 }
 
-/// A fn item that writes to a field of `Point` but does not invoke methods
+/// A function item that writes to a field of `Point` but does not invoke methods.
 pub mod fn_write_field {
     use point::Point;
 
diff --git a/src/test/incremental/change_name_of_static_in_fn.rs b/src/test/incremental/change_name_of_static_in_fn.rs
new file mode 100644
index 0000000000000..5b27b6808ead2
--- /dev/null
+++ b/src/test/incremental/change_name_of_static_in_fn.rs
@@ -0,0 +1,17 @@
+
+// revisions:rpass1 rpass2 rpass3
+
+// See issue #57692.
+
+#![allow(warnings)]
+
+fn main() {
+    #[cfg(rpass1)]
+    {
+        static map: u64 = 0;
+    }
+    #[cfg(not(rpass1))]
+    {
+        static MAP: u64 = 0;
+    }
+}
diff --git a/src/test/incremental/hashes/call_expressions.rs b/src/test/incremental/hashes/call_expressions.rs
index 52de065598965..f0f1f09a8388b 100644
--- a/src/test/incremental/hashes/call_expressions.rs
+++ b/src/test/incremental/hashes/call_expressions.rs
@@ -25,7 +25,7 @@ pub fn change_callee_function() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_callee_function() {
     callee2(1, 2)
@@ -40,7 +40,7 @@ pub fn change_argument_function() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_argument_function() {
     callee1(1, 3)
@@ -81,7 +81,7 @@ pub fn change_callee_method() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_callee_method() {
     let s = Struct;
@@ -98,7 +98,7 @@ pub fn change_argument_method() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_argument_method() {
     let s = Struct;
@@ -115,7 +115,7 @@ pub fn change_ufcs_callee_method() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_ufcs_callee_method() {
     let s = Struct;
@@ -132,7 +132,7 @@ pub fn change_argument_method_ufcs() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_argument_method_ufcs() {
     let s = Struct;
@@ -149,7 +149,7 @@ pub fn change_to_ufcs() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 // One might think this would be expanded in the HirBody/Mir, but it actually
 // results in slightly different Hir/Mir.
@@ -171,7 +171,7 @@ pub mod change_ufcs_callee_indirectly {
     #[cfg(not(cfail1))]
     use super::Struct2 as Struct;
 
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
 
 
diff --git a/src/test/incremental/hashes/closure_expressions.rs b/src/test/incremental/hashes/closure_expressions.rs
index 0e8cf80b88981..4e82729aa3be1 100644
--- a/src/test/incremental/hashes/closure_expressions.rs
+++ b/src/test/incremental/hashes/closure_expressions.rs
@@ -37,7 +37,7 @@ pub fn add_parameter() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_parameter() {
     let x = 0u32;
@@ -53,7 +53,7 @@ pub fn change_parameter_pattern() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_parameter_pattern() {
     let _ = |&x: &u32| x;
@@ -84,7 +84,7 @@ pub fn add_type_ascription_to_parameter() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_type_ascription_to_parameter() {
     let closure = |x: u32| x + 1u32;
@@ -101,7 +101,7 @@ pub fn change_parameter_type() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_parameter_type() {
     let closure = |x: u16| (x as u64) + 1;
diff --git a/src/test/incremental/hashes/enum_constructors.rs b/src/test/incremental/hashes/enum_constructors.rs
index e9b557bde20f7..a74c3ab04e2af 100644
--- a/src/test/incremental/hashes/enum_constructors.rs
+++ b/src/test/incremental/hashes/enum_constructors.rs
@@ -34,7 +34,7 @@ pub fn change_field_value_struct_like() -> Enum {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_field_value_struct_like() -> Enum {
     Enum::Struct {
@@ -96,7 +96,7 @@ pub fn change_constructor_path_struct_like() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_struct_like() {
     let _ = Enum2::Struct {
@@ -119,7 +119,7 @@ pub fn change_constructor_variant_struct_like() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_variant_struct_like() {
     let _ = Enum2::Struct2 {
@@ -139,7 +139,7 @@ pub mod change_constructor_path_indirectly_struct_like {
 
     #[rustc_clean(
         cfg="cfail2",
-        except="FnSignature,Hir,HirBody,MirOptimized,MirValidated,\
+        except="FnSignature,Hir,HirBody,MirOptimized,MirBuilt,\
                 TypeckTables"
     )]
     #[rustc_clean(cfg="cfail3")]
@@ -161,7 +161,7 @@ pub mod change_constructor_variant_indirectly_struct_like {
     #[cfg(not(cfail1))]
     use super::Enum2::Struct2 as Variant;
 
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
     #[rustc_clean(cfg="cfail3")]
     pub fn function() -> Enum2 {
         Variant {
@@ -180,7 +180,7 @@ pub fn change_field_value_tuple_like() -> Enum {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_field_value_tuple_like() -> Enum {
     Enum::Tuple(0, 1, 3)
@@ -197,7 +197,7 @@ pub fn change_constructor_path_tuple_like() {
 #[cfg(not(cfail1))]
 #[rustc_clean(
     cfg="cfail2",
-    except="HirBody,MirOptimized,MirValidated,TypeckTables"
+    except="HirBody,MirOptimized,MirBuilt,TypeckTables"
 )]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_tuple_like() {
@@ -215,7 +215,7 @@ pub fn change_constructor_variant_tuple_like() {
 #[cfg(not(cfail1))]
 #[rustc_clean(
     cfg="cfail2",
-    except="HirBody,MirOptimized,MirValidated,TypeckTables"
+    except="HirBody,MirOptimized,MirBuilt,TypeckTables"
 )]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_variant_tuple_like() {
@@ -232,7 +232,7 @@ pub mod change_constructor_path_indirectly_tuple_like {
 
     #[rustc_clean(
         cfg="cfail2",
-        except="FnSignature,Hir,HirBody,MirOptimized,MirValidated,\
+        except="FnSignature,Hir,HirBody,MirOptimized,MirBuilt,\
                 TypeckTables"
     )]
     #[rustc_clean(cfg="cfail3")]
@@ -251,7 +251,7 @@ pub mod change_constructor_variant_indirectly_tuple_like {
     #[cfg(not(cfail1))]
     use super::Enum2::Tuple2 as Variant;
 
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     pub fn function() -> Enum2 {
         Variant(0, 1, 2)
@@ -278,7 +278,7 @@ pub fn change_constructor_path_c_like() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_c_like() {
     let _ = Clike2::B;
@@ -293,7 +293,7 @@ pub fn change_constructor_variant_c_like() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_variant_c_like() {
     let _ = Clike::C;
@@ -309,7 +309,7 @@ pub mod change_constructor_path_indirectly_c_like {
 
     #[rustc_clean(
         cfg="cfail2",
-        except="FnSignature,Hir,HirBody,MirOptimized,MirValidated,\
+        except="FnSignature,Hir,HirBody,MirOptimized,MirBuilt,\
                 TypeckTables"
     )]
     #[rustc_clean(cfg="cfail3")]
@@ -328,7 +328,7 @@ pub mod change_constructor_variant_indirectly_c_like {
     #[cfg(not(cfail1))]
     use super::Clike::B as Variant;
 
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
     #[rustc_clean(cfg="cfail3")]
     pub fn function() -> Clike {
         Variant
diff --git a/src/test/incremental/hashes/exported_vs_not.rs b/src/test/incremental/hashes/exported_vs_not.rs
index 1880dd2fb0d7c..c9f844f96ebd7 100644
--- a/src/test/incremental/hashes/exported_vs_not.rs
+++ b/src/test/incremental/hashes/exported_vs_not.rs
@@ -16,7 +16,7 @@ pub fn body_not_exported_to_metadata() -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn body_not_exported_to_metadata() -> u32 {
     2
@@ -35,7 +35,7 @@ pub fn body_exported_to_metadata_because_of_inline() -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[inline]
 pub fn body_exported_to_metadata_because_of_inline() -> u32 {
@@ -55,7 +55,7 @@ pub fn body_exported_to_metadata_because_of_generic() -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[inline]
 pub fn body_exported_to_metadata_because_of_generic() -> u32 {
diff --git a/src/test/incremental/hashes/for_loops.rs b/src/test/incremental/hashes/for_loops.rs
index 90c1ecf10c707..da093ded63566 100644
--- a/src/test/incremental/hashes/for_loops.rs
+++ b/src/test/incremental/hashes/for_loops.rs
@@ -25,7 +25,7 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -48,7 +48,7 @@ pub fn change_iteration_variable_name() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_iteration_variable_name() {
     let mut _x = 0;
@@ -71,7 +71,7 @@ pub fn change_iteration_variable_pattern() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_iteration_variable_pattern() {
     let mut _x = 0;
@@ -94,7 +94,7 @@ pub fn change_iterable() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_iterable() {
     let mut _x = 0;
@@ -116,7 +116,7 @@ pub fn add_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_break() {
     let mut _x = 0;
@@ -187,7 +187,7 @@ pub fn change_break_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_break_label() {
     let mut _x = 0;
@@ -237,7 +237,7 @@ pub fn change_continue_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_label() {
     let mut _x = 0;
@@ -262,7 +262,7 @@ pub fn change_continue_to_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_to_break() {
     let mut _x = 0;
diff --git a/src/test/incremental/hashes/function_interfaces.rs b/src/test/incremental/hashes/function_interfaces.rs
index 21263c8b6c614..4330b0025a251 100644
--- a/src/test/incremental/hashes/function_interfaces.rs
+++ b/src/test/incremental/hashes/function_interfaces.rs
@@ -24,7 +24,7 @@ pub fn add_parameter() {}
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg = "cfail2",
-              except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+              except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub fn add_parameter(p: i32) {}
 
@@ -47,7 +47,7 @@ pub fn type_of_parameter(p: i32) {}
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg = "cfail2",
-              except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+              except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub fn type_of_parameter(p: i64) {}
 
@@ -59,7 +59,7 @@ pub fn type_of_parameter_ref(p: &i32) {}
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg = "cfail2",
-              except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+              except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub fn type_of_parameter_ref(p: &mut i32) {}
 
@@ -71,7 +71,7 @@ pub fn order_of_parameters(p1: i32, p2: i64) {}
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg = "cfail2",
-              except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+              except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub fn order_of_parameters(p2: i64, p1: i32) {}
 
@@ -83,7 +83,7 @@ pub fn make_unsafe() {}
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg = "cfail2",
-              except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+              except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub unsafe fn make_unsafe() {}
 
@@ -94,7 +94,7 @@ pub unsafe fn make_unsafe() {}
 pub fn make_extern() {}
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg = "cfail2", except = "Hir, HirBody, TypeckTables, FnSignature")]
+#[rustc_clean(cfg = "cfail2", except = "Hir, HirBody, MirBuilt, TypeckTables, FnSignature")]
 #[rustc_clean(cfg = "cfail3")]
 pub extern "C" fn make_extern() {}
 
@@ -292,7 +292,7 @@ pub mod change_return_type_indirectly {
     use super::ReferencedType2 as ReturnType;
 
     #[rustc_clean(cfg = "cfail2",
-                  except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+                  except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
     #[rustc_clean(cfg = "cfail3")]
     pub fn indirect_return_type() -> ReturnType {
         ReturnType {}
@@ -309,7 +309,7 @@ pub mod change_parameter_type_indirectly {
     use super::ReferencedType2 as ParameterType;
 
     #[rustc_clean(cfg = "cfail2",
-                  except = "Hir, HirBody, MirValidated, MirOptimized, TypeckTables, FnSignature")]
+                  except = "Hir, HirBody, MirBuilt, MirOptimized, TypeckTables, FnSignature")]
     #[rustc_clean(cfg = "cfail3")]
     pub fn indirect_parameter_type(p: ParameterType) {}
 }
diff --git a/src/test/incremental/hashes/if_expressions.rs b/src/test/incremental/hashes/if_expressions.rs
index 18dba63072bad..a01247ff4243c 100644
--- a/src/test/incremental/hashes/if_expressions.rs
+++ b/src/test/incremental/hashes/if_expressions.rs
@@ -25,7 +25,7 @@ pub fn change_condition(x: bool) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_condition(x: bool) -> u32 {
     if !x {
@@ -46,7 +46,7 @@ pub fn change_then_branch(x: bool) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_then_branch(x: bool) -> u32 {
     if x {
@@ -69,7 +69,7 @@ pub fn change_else_branch(x: bool) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_else_branch(x: bool) -> u32 {
     if x {
@@ -120,7 +120,7 @@ pub fn change_condition_if_let(x: Option<u32>) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_condition_if_let(x: Option<u32>) -> u32 {
     if let Some(_) = x {
@@ -143,7 +143,7 @@ pub fn change_then_branch_if_let(x: Option<u32>) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_then_branch_if_let(x: Option<u32>) -> u32 {
     if let Some(x) = x {
@@ -166,7 +166,7 @@ pub fn change_else_branch_if_let(x: Option<u32>) -> u32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_else_branch_if_let(x: Option<u32>) -> u32 {
     if let Some(x) = x {
diff --git a/src/test/incremental/hashes/inherent_impls.rs b/src/test/incremental/hashes/inherent_impls.rs
index 92ce5a606bf90..d1574aee9a9c0 100644
--- a/src/test/incremental/hashes/inherent_impls.rs
+++ b/src/test/incremental/hashes/inherent_impls.rs
@@ -42,7 +42,7 @@ impl Foo {
 #[rustc_clean(cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 impl Foo {
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     pub fn method_body() {
         println!("Hello, world!");
@@ -63,7 +63,7 @@ impl Foo {
 #[rustc_clean(cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 impl Foo {
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     #[inline]
     pub fn method_body_inlined() {
@@ -114,7 +114,7 @@ impl Foo {
 impl Foo {
     #[rustc_clean(
         cfg="cfail2",
-        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirValidated"
+        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirBuilt"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub fn method_selfmutness(&mut self) { }
@@ -154,7 +154,7 @@ impl Foo {
 impl Foo {
     #[rustc_clean(
         cfg="cfail2",
-        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirValidated"
+        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirBuilt"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub fn add_method_parameter(&self, _: i32) { }
@@ -172,7 +172,7 @@ impl Foo {
 #[rustc_clean(cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 impl Foo {
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
     #[rustc_clean(cfg="cfail3")]
     pub fn change_method_parameter_name(&self, b: i64) { }
 }
@@ -191,7 +191,7 @@ impl Foo {
 impl Foo {
     #[rustc_clean(
         cfg="cfail2",
-        except="Hir,HirBody,FnSignature,MirOptimized,MirValidated,TypeckTables")]
+        except="Hir,HirBody,FnSignature,MirOptimized,MirBuilt,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     pub fn change_method_return_type(&self) -> u8 { 0 }
 }
@@ -226,7 +226,7 @@ impl Foo {
 #[rustc_clean(cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 impl Foo {
-    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+    #[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
     #[rustc_clean(cfg="cfail3")]
     pub fn change_method_parameter_order(&self, b: i64, a: i64) { }
 }
@@ -245,7 +245,7 @@ impl Foo {
 impl Foo {
     #[rustc_clean(
         cfg="cfail2",
-        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirValidated"
+        except="Hir,HirBody,FnSignature,TypeckTables,MirOptimized,MirBuilt"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub unsafe fn make_method_unsafe(&self) { }
@@ -263,7 +263,7 @@ impl Foo {
 #[rustc_clean(cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 impl Foo {
-    #[rustc_clean(cfg="cfail2", except="Hir,HirBody,FnSignature,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="Hir,HirBody,MirBuilt,FnSignature,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     pub extern fn make_method_extern(&self) { }
 }
@@ -447,7 +447,7 @@ impl Bar<u32> {
 impl<T> Bar<T> {
     #[rustc_clean(
         cfg="cfail2",
-        except="GenericsOfItem,FnSignature,TypeckTables,TypeOfItem,MirOptimized,MirValidated"
+        except="GenericsOfItem,FnSignature,TypeckTables,TypeOfItem,MirOptimized,MirBuilt"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub fn add_type_parameter_to_impl(&self) { }
@@ -465,7 +465,7 @@ impl Bar<u32> {
 #[rustc_clean(cfg="cfail2", except="Hir,HirBody")]
 #[rustc_clean(cfg="cfail3")]
 impl Bar<u64> {
-    #[rustc_clean(cfg="cfail2", except="FnSignature,MirOptimized,MirValidated,TypeckTables")]
+    #[rustc_clean(cfg="cfail2", except="FnSignature,MirOptimized,MirBuilt,TypeckTables")]
     #[rustc_clean(cfg="cfail3")]
     pub fn change_impl_self_type(&self) { }
 }
diff --git a/src/test/incremental/hashes/inline_asm.rs b/src/test/incremental/hashes/inline_asm.rs
index e73aa89a8374d..c5e7f525fd0fb 100644
--- a/src/test/incremental/hashes/inline_asm.rs
+++ b/src/test/incremental/hashes/inline_asm.rs
@@ -33,7 +33,7 @@ pub fn change_template(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_template(a: i32) -> i32 {
@@ -69,7 +69,7 @@ pub fn change_output(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_output(a: i32) -> i32 {
@@ -105,7 +105,7 @@ pub fn change_input(_a: i32, _b: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_input(_a: i32, _b: i32) -> i32 {
@@ -140,7 +140,7 @@ pub fn change_input_constraint(_a: i32, _b: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_input_constraint(_a: i32, _b: i32) -> i32 {
@@ -175,7 +175,7 @@ pub fn change_clobber(_a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_clobber(_a: i32) -> i32 {
@@ -210,7 +210,7 @@ pub fn change_options(_a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 pub fn change_options(_a: i32) -> i32 {
diff --git a/src/test/incremental/hashes/let_expressions.rs b/src/test/incremental/hashes/let_expressions.rs
index b6050f059c27b..a2b33fecea865 100644
--- a/src/test/incremental/hashes/let_expressions.rs
+++ b/src/test/incremental/hashes/let_expressions.rs
@@ -22,7 +22,7 @@ pub fn change_name() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_name() {
     let _y = 2u64;
@@ -38,7 +38,7 @@ pub fn add_type() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_type() {
     let _x: u32 = 2u32;
@@ -54,7 +54,7 @@ pub fn change_type() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_type() {
     let _x: u8 = 2;
@@ -70,7 +70,7 @@ pub fn change_mutability_of_reference_type() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_mutability_of_reference_type() {
     let _x: &mut u64;
@@ -86,7 +86,7 @@ pub fn change_mutability_of_slot() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_mutability_of_slot() {
     let _x: u64 = 0;
@@ -102,7 +102,7 @@ pub fn change_simple_binding_to_pattern() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_simple_binding_to_pattern() {
     let (_a, _b) = (0u8, 'x');
@@ -118,7 +118,7 @@ pub fn change_name_in_pattern() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_name_in_pattern() {
     let (_a, _c) = (1u8, 'y');
@@ -134,7 +134,7 @@ pub fn add_ref_in_pattern() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_ref_in_pattern() {
     let (ref _a, _b) = (1u8, 'y');
@@ -150,7 +150,7 @@ pub fn add_amp_in_pattern() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_amp_in_pattern() {
     let (&_a, _b) = (&1u8, 'y');
@@ -166,7 +166,7 @@ pub fn change_mutability_of_binding_in_pattern() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_mutability_of_binding_in_pattern() {
     let (mut _a, _b) = (99u8, 'q');
@@ -182,7 +182,7 @@ pub fn add_initializer() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,TypeckTables,MirValidated,MirOptimized")]
+    except="HirBody,TypeckTables,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_initializer() {
     let _x: i16 = 3i16;
@@ -198,7 +198,7 @@ pub fn change_initializer() {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_initializer() {
     let _x = 5u16;
diff --git a/src/test/incremental/hashes/loop_expressions.rs b/src/test/incremental/hashes/loop_expressions.rs
index a218b01fc8512..a48d150b8b0f2 100644
--- a/src/test/incremental/hashes/loop_expressions.rs
+++ b/src/test/incremental/hashes/loop_expressions.rs
@@ -25,7 +25,7 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -47,7 +47,7 @@ pub fn add_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_break() {
     let mut _x = 0;
@@ -118,7 +118,7 @@ pub fn change_break_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_break_label() {
     let mut _x = 0;
@@ -168,7 +168,7 @@ pub fn change_continue_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_label() {
     let mut _x = 0;
@@ -193,7 +193,7 @@ pub fn change_continue_to_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_to_break() {
     let mut _x = 0;
diff --git a/src/test/incremental/hashes/match_expressions.rs b/src/test/incremental/hashes/match_expressions.rs
index b6b934eb7d508..11fe84d88e9b3 100644
--- a/src/test/incremental/hashes/match_expressions.rs
+++ b/src/test/incremental/hashes/match_expressions.rs
@@ -26,7 +26,7 @@ pub fn add_arm(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_arm(x: u32) -> u32 {
     match x {
@@ -51,7 +51,7 @@ pub fn change_order_of_arms(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_order_of_arms(x: u32) -> u32 {
     match x {
@@ -75,7 +75,7 @@ pub fn add_guard_clause(x: u32, y: bool) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_guard_clause(x: u32, y: bool) -> u32 {
     match x {
@@ -99,7 +99,7 @@ pub fn change_guard_clause(x: u32, y: bool) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_guard_clause(x: u32, y: bool) -> u32 {
     match x {
@@ -123,7 +123,7 @@ pub fn add_at_binding(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_at_binding(x: u32) -> u32 {
     match x {
@@ -147,7 +147,7 @@ pub fn change_name_of_at_binding(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_name_of_at_binding(x: u32) -> u32 {
     match x {
@@ -170,7 +170,7 @@ pub fn change_simple_name_to_pattern(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_simple_name_to_pattern(x: u32) -> u32 {
     match (x, x & 1) {
@@ -193,7 +193,7 @@ pub fn change_name_in_pattern(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_name_in_pattern(x: u32) -> u32 {
     match (x, x & 1) {
@@ -216,7 +216,7 @@ pub fn change_mutability_of_binding_in_pattern(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_mutability_of_binding_in_pattern(x: u32) -> u32 {
     match (x, x & 1) {
@@ -238,7 +238,7 @@ pub fn add_ref_to_binding_in_pattern(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_ref_to_binding_in_pattern(x: u32) -> u32 {
     match (x, x & 1) {
@@ -260,7 +260,7 @@ pub fn add_amp_to_binding_in_pattern(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_amp_to_binding_in_pattern(x: u32) -> u32 {
     match (&x, x & 1) {
@@ -283,7 +283,7 @@ pub fn change_rhs_of_arm(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized")]
+    except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_rhs_of_arm(x: u32) -> u32 {
     match x {
@@ -307,7 +307,7 @@ pub fn add_alternative_to_arm(x: u32) -> u32 {
 
 #[cfg(not(cfail1))]
 #[rustc_clean(cfg="cfail2",
-    except="HirBody,MirValidated,MirOptimized,TypeckTables")]
+    except="HirBody,MirBuilt,MirOptimized,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_alternative_to_arm(x: u32) -> u32 {
     match x {
diff --git a/src/test/incremental/hashes/panic_exprs.rs b/src/test/incremental/hashes/panic_exprs.rs
index 3ae2c396d829c..9a3c93147a098 100644
--- a/src/test/incremental/hashes/panic_exprs.rs
+++ b/src/test/incremental/hashes/panic_exprs.rs
@@ -18,7 +18,7 @@
 
 
 // Indexing expression ---------------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn indexing(slice: &[u8]) -> u8 {
     #[cfg(cfail1)]
@@ -33,7 +33,7 @@ pub fn indexing(slice: &[u8]) -> u8 {
 
 
 // Arithmetic overflow plus ----------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn arithmetic_overflow_plus(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -48,7 +48,7 @@ pub fn arithmetic_overflow_plus(val: i32) -> i32 {
 
 
 // Arithmetic overflow minus ----------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn arithmetic_overflow_minus(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -63,7 +63,7 @@ pub fn arithmetic_overflow_minus(val: i32) -> i32 {
 
 
 // Arithmetic overflow mult ----------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn arithmetic_overflow_mult(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -78,7 +78,7 @@ pub fn arithmetic_overflow_mult(val: i32) -> i32 {
 
 
 // Arithmetic overflow negation ------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn arithmetic_overflow_negation(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -93,7 +93,7 @@ pub fn arithmetic_overflow_negation(val: i32) -> i32 {
 
 
 // Division by zero ------------------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn division_by_zero(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -107,7 +107,7 @@ pub fn division_by_zero(val: i32) -> i32 {
 }
 
 // Division by zero ------------------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn mod_by_zero(val: i32) -> i32 {
     #[cfg(cfail1)]
@@ -122,7 +122,7 @@ pub fn mod_by_zero(val: i32) -> i32 {
 
 
 // shift left ------------------------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn shift_left(val: i32, shift: usize) -> i32 {
     #[cfg(cfail1)]
@@ -137,7 +137,7 @@ pub fn shift_left(val: i32, shift: usize) -> i32 {
 
 
 // shift right ------------------------------------------------------------------
-#[rustc_clean(cfg="cfail2", except="HirBody,MirValidated,MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirBuilt,MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn shift_right(val: i32, shift: usize) -> i32 {
     #[cfg(cfail1)]
diff --git a/src/test/incremental/hashes/struct_constructors.rs b/src/test/incremental/hashes/struct_constructors.rs
index 5444fe78f0a47..a42fda3188520 100644
--- a/src/test/incremental/hashes/struct_constructors.rs
+++ b/src/test/incremental/hashes/struct_constructors.rs
@@ -31,7 +31,7 @@ pub fn change_field_value_regular_struct() -> RegularStruct {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_field_value_regular_struct() -> RegularStruct {
     RegularStruct {
@@ -82,7 +82,7 @@ pub fn add_field_regular_struct() -> RegularStruct {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_field_regular_struct() -> RegularStruct {
     let struct1 = RegularStruct {
@@ -117,7 +117,7 @@ pub fn change_field_label_regular_struct() -> RegularStruct {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_field_label_regular_struct() -> RegularStruct {
     let struct1 = RegularStruct {
@@ -152,7 +152,7 @@ pub fn change_constructor_path_regular_struct() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_regular_struct() {
     let _ = RegularStruct2 {
@@ -173,7 +173,7 @@ pub mod change_constructor_path_indirectly_regular_struct {
 
     #[rustc_clean(
         cfg="cfail2",
-        except="FnSignature,Hir,HirBody,MirOptimized,MirValidated,TypeckTables"
+        except="FnSignature,Hir,HirBody,MirOptimized,MirBuilt,TypeckTables"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub fn function() -> Struct {
@@ -196,7 +196,7 @@ pub fn change_field_value_tuple_struct() -> TupleStruct {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_field_value_tuple_struct() -> TupleStruct {
     TupleStruct(0, 1, 3)
@@ -213,7 +213,7 @@ pub fn change_constructor_path_tuple_struct() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirValidated,TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody,MirOptimized,MirBuilt,TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_constructor_path_tuple_struct() {
     let _ = TupleStruct2(0, 1, 2);
@@ -230,7 +230,7 @@ pub mod change_constructor_path_indirectly_tuple_struct {
 
     #[rustc_clean(
         cfg="cfail2",
-        except="FnSignature,Hir,HirBody,MirOptimized,MirValidated,TypeckTables"
+        except="FnSignature,Hir,HirBody,MirOptimized,MirBuilt,TypeckTables"
     )]
     #[rustc_clean(cfg="cfail3")]
     pub fn function() -> Struct {
diff --git a/src/test/incremental/hashes/unary_and_binary_exprs.rs b/src/test/incremental/hashes/unary_and_binary_exprs.rs
index 26cc41fd8186c..ef8035a300a43 100644
--- a/src/test/incremental/hashes/unary_and_binary_exprs.rs
+++ b/src/test/incremental/hashes/unary_and_binary_exprs.rs
@@ -21,7 +21,7 @@ pub fn const_negation() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn const_negation() -> i32 {
     -1
@@ -36,7 +36,7 @@ pub fn const_bitwise_not() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn const_bitwise_not() -> i32 {
     !99
@@ -51,7 +51,7 @@ pub fn var_negation(x: i32, y: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn var_negation(x: i32, y: i32) -> i32 {
     -y
@@ -66,7 +66,7 @@ pub fn var_bitwise_not(x: i32, y: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn var_bitwise_not(x: i32, y: i32) -> i32 {
     !y
@@ -81,7 +81,7 @@ pub fn var_deref(x: &i32, y: &i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated,TypeckTables", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt,TypeckTables", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn var_deref(x: &i32, y: &i32) -> i32 {
     *y
@@ -96,7 +96,7 @@ pub fn first_const_add() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn first_const_add() -> i32 {
     2 + 3
@@ -111,7 +111,7 @@ pub fn second_const_add() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn second_const_add() -> i32 {
     1 + 3
@@ -126,7 +126,7 @@ pub fn first_var_add(a: i32, b: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn first_var_add(a: i32, b: i32) -> i32 {
     b + 2
@@ -141,7 +141,7 @@ pub fn second_var_add(a: i32, b: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn second_var_add(a: i32, b: i32) -> i32 {
     1 + b
@@ -156,7 +156,7 @@ pub fn plus_to_minus(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn plus_to_minus(a: i32) -> i32 {
     1 - a
@@ -171,7 +171,7 @@ pub fn plus_to_mult(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn plus_to_mult(a: i32) -> i32 {
     1 * a
@@ -186,7 +186,7 @@ pub fn plus_to_div(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn plus_to_div(a: i32) -> i32 {
     1 / a
@@ -201,7 +201,7 @@ pub fn plus_to_mod(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn plus_to_mod(a: i32) -> i32 {
     1 % a
@@ -216,7 +216,7 @@ pub fn and_to_or(a: bool, b: bool) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn and_to_or(a: bool, b: bool) -> bool {
     a || b
@@ -231,7 +231,7 @@ pub fn bitwise_and_to_bitwise_or(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn bitwise_and_to_bitwise_or(a: i32) -> i32 {
     1 | a
@@ -246,7 +246,7 @@ pub fn bitwise_and_to_bitwise_xor(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn bitwise_and_to_bitwise_xor(a: i32) -> i32 {
     1 ^ a
@@ -261,7 +261,7 @@ pub fn bitwise_and_to_lshift(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn bitwise_and_to_lshift(a: i32) -> i32 {
     a << 1
@@ -276,7 +276,7 @@ pub fn bitwise_and_to_rshift(a: i32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn bitwise_and_to_rshift(a: i32) -> i32 {
     a >> 1
@@ -291,7 +291,7 @@ pub fn eq_to_uneq(a: i32) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn eq_to_uneq(a: i32) -> bool {
     a != 1
@@ -306,7 +306,7 @@ pub fn eq_to_lt(a: i32) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn eq_to_lt(a: i32) -> bool {
     a < 1
@@ -321,7 +321,7 @@ pub fn eq_to_gt(a: i32) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn eq_to_gt(a: i32) -> bool {
     a > 1
@@ -336,7 +336,7 @@ pub fn eq_to_le(a: i32) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn eq_to_le(a: i32) -> bool {
     a <= 1
@@ -351,7 +351,7 @@ pub fn eq_to_ge(a: i32) -> bool {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn eq_to_ge(a: i32) -> bool {
     a >= 1
@@ -368,7 +368,7 @@ pub fn type_cast(a: u8) -> u64 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated,TypeckTables", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt,TypeckTables", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn type_cast(a: u8) -> u64 {
     let b = a as u32;
@@ -385,7 +385,7 @@ pub fn value_cast(a: u32) -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn value_cast(a: u32) -> i32 {
     2 as i32
@@ -403,7 +403,7 @@ pub fn place() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn place() -> i32 {
     let mut x = 10;
@@ -423,7 +423,7 @@ pub fn rvalue() -> i32 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn rvalue() -> i32 {
     let mut x = 10;
@@ -440,7 +440,7 @@ pub fn index_to_slice(s: &[u8], i: usize, j: usize) -> u8 {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(except="HirBody,MirOptimized,MirValidated", cfg="cfail2")]
+#[rustc_clean(except="HirBody,MirOptimized,MirBuilt", cfg="cfail2")]
 #[rustc_clean(cfg="cfail3")]
 pub fn index_to_slice(s: &[u8], i: usize, j: usize) -> u8 {
     s[j]
diff --git a/src/test/incremental/hashes/while_let_loops.rs b/src/test/incremental/hashes/while_let_loops.rs
index edfea05ae9835..c708d5b969df5 100644
--- a/src/test/incremental/hashes/while_let_loops.rs
+++ b/src/test/incremental/hashes/while_let_loops.rs
@@ -25,7 +25,7 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -48,7 +48,7 @@ pub fn change_loop_condition() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_condition() {
     let mut _x = 0;
@@ -70,7 +70,7 @@ pub fn add_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_break() {
     let mut _x = 0;
@@ -141,7 +141,7 @@ pub fn change_break_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_break_label() {
     let mut _x = 0;
@@ -191,7 +191,7 @@ pub fn change_continue_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_label() {
     let mut _x = 0;
@@ -216,7 +216,7 @@ pub fn change_continue_to_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_to_break() {
     let mut _x = 0;
diff --git a/src/test/incremental/hashes/while_loops.rs b/src/test/incremental/hashes/while_loops.rs
index 85c2c9fa25064..c7b84a120c8df 100644
--- a/src/test/incremental/hashes/while_loops.rs
+++ b/src/test/incremental/hashes/while_loops.rs
@@ -25,7 +25,7 @@ pub fn change_loop_body() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_body() {
     let mut _x = 0;
@@ -48,7 +48,7 @@ pub fn change_loop_condition() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_loop_condition() {
     let mut _x = 0;
@@ -70,7 +70,7 @@ pub fn add_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized, TypeckTables")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized, TypeckTables")]
 #[rustc_clean(cfg="cfail3")]
 pub fn add_break() {
     let mut _x = 0;
@@ -141,7 +141,7 @@ pub fn change_break_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_break_label() {
     let mut _x = 0;
@@ -191,7 +191,7 @@ pub fn change_continue_label() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_label() {
     let mut _x = 0;
@@ -216,7 +216,7 @@ pub fn change_continue_to_break() {
 }
 
 #[cfg(not(cfail1))]
-#[rustc_clean(cfg="cfail2", except="HirBody, MirValidated, MirOptimized")]
+#[rustc_clean(cfg="cfail2", except="HirBody, MirBuilt, MirOptimized")]
 #[rustc_clean(cfg="cfail3")]
 pub fn change_continue_to_break() {
     let mut _x = 0;
diff --git a/src/test/incremental/issue-54242.rs b/src/test/incremental/issue-54242.rs
new file mode 100644
index 0000000000000..1c700d44dd80b
--- /dev/null
+++ b/src/test/incremental/issue-54242.rs
@@ -0,0 +1,17 @@
+// revisions: rpass cfail
+
+trait Tr {
+    type Arr;
+
+    const C: usize = 0;
+}
+
+impl Tr for str {
+    #[cfg(rpass)]
+    type Arr = [u8; 8];
+    #[cfg(cfail)]
+    type Arr = [u8; Self::C];
+    //[cfail]~^ ERROR cycle detected when const-evaluating
+}
+
+fn main() {}
diff --git a/src/test/incremental/lto.rs b/src/test/incremental/lto.rs
new file mode 100644
index 0000000000000..2a3e3c2467cdc
--- /dev/null
+++ b/src/test/incremental/lto.rs
@@ -0,0 +1,40 @@
+// no-prefer-dynamic
+// revisions:rpass1 rpass2
+// compile-flags: -C lto
+
+mod x {
+    pub struct X {
+        x: u32, y: u32,
+    }
+
+    #[cfg(rpass1)]
+    fn make() -> X {
+        X { x: 22, y: 0 }
+    }
+
+    #[cfg(rpass2)]
+    fn make() -> X {
+        X { x: 11, y: 11 }
+    }
+
+    pub fn new() -> X {
+        make()
+    }
+
+    pub fn sum(x: &X) -> u32 {
+        x.x + x.y
+    }
+}
+
+mod y {
+    use x;
+
+    pub fn assert_sum() -> bool {
+        let x = x::new();
+        x::sum(&x) == 22
+    }
+}
+
+pub fn main() {
+    y::assert_sum();
+}
diff --git a/src/test/mir-opt/basic_assignment.rs b/src/test/mir-opt/basic_assignment.rs
index 88fd53d4ba59d..1bbbe67a12cb8 100644
--- a/src/test/mir-opt/basic_assignment.rs
+++ b/src/test/mir-opt/basic_assignment.rs
@@ -37,7 +37,7 @@ fn main() {
 //        StorageLive(_4);
 //        _4 = std::option::Option<std::boxed::Box<u32>>::None;
 //        FakeRead(ForLet, _4);
-//        AscribeUserType(_4, o, UserTypeProjection { base: UserTypeAnnotation(1), projs: [] });
+//        AscribeUserType(_4, o, UserTypeProjection { base: UserType(1), projs: [] });
 //        StorageLive(_5);
 //        StorageLive(_6);
 //        _6 = move _4;
diff --git a/src/test/mir-opt/inline-any-operand.rs b/src/test/mir-opt/inline-any-operand.rs
index 5fafc2c50cac2..b545500371936 100644
--- a/src/test/mir-opt/inline-any-operand.rs
+++ b/src/test/mir-opt/inline-any-operand.rs
@@ -6,16 +6,16 @@ fn main() {
     println!("{}", bar());
 }
 
-#[inline(always)]
-fn foo(x: i32, y: i32) -> bool {
-    x == y
-}
-
 fn bar() -> bool {
     let f = foo;
     f(1, -1)
 }
 
+#[inline(always)]
+fn foo(x: i32, y: i32) -> bool {
+    x == y
+}
+
 // END RUST SOURCE
 // START rustc.bar.Inline.after.mir
 // ...
diff --git a/src/test/mir-opt/inline-retag.rs b/src/test/mir-opt/inline-retag.rs
index e91a5c223513a..6cdbcfdb0add7 100644
--- a/src/test/mir-opt/inline-retag.rs
+++ b/src/test/mir-opt/inline-retag.rs
@@ -6,16 +6,16 @@ fn main() {
     println!("{}", bar());
 }
 
-#[inline(always)]
-fn foo(x: &i32, y: &i32) -> bool {
-    *x == *y
-}
-
 fn bar() -> bool {
     let f = foo;
     f(&1, &-1)
 }
 
+#[inline(always)]
+fn foo(x: &i32, y: &i32) -> bool {
+    *x == *y
+}
+
 // END RUST SOURCE
 // START rustc.bar.Inline.after.mir
 // ...
diff --git a/src/test/mir-opt/inline-trait-method_2.rs b/src/test/mir-opt/inline-trait-method_2.rs
index aa756f4a23370..8f9f2535aa5f8 100644
--- a/src/test/mir-opt/inline-trait-method_2.rs
+++ b/src/test/mir-opt/inline-trait-method_2.rs
@@ -1,14 +1,14 @@
 // compile-flags: -Z span_free_formats -Z mir-opt-level=3
 
+fn test2(x: &dyn X) -> bool {
+    test(x)
+}
+
 #[inline]
 fn test(x: &dyn X) -> bool {
     x.y()
 }
 
-fn test2(x: &dyn X) -> bool {
-    test(x)
-}
-
 trait X {
     fn y(&self) -> bool {
         false
diff --git a/src/test/mir-opt/retag.rs b/src/test/mir-opt/retag.rs
index 5b00c5c460316..bb794409ae01f 100644
--- a/src/test/mir-opt/retag.rs
+++ b/src/test/mir-opt/retag.rs
@@ -75,18 +75,18 @@ fn main() {
 //         _10 = move _8;
 //         Retag(_10);
 //         ...
-//         _14 = &mut (*_10);
-//         Retag(_14);
-//         _13 = move _14 as *mut i32 (Misc);
-//         Retag([raw] _13);
+//         _15 = &mut (*_10);
+//         Retag(_15);
+//         _14 = move _15 as *mut i32 (Misc);
+//         Retag([raw] _14);
 //         ...
-//         _17 = move _18(move _19) -> bb2;
+//         _18 = move _19(move _20) -> bb2;
 //     }
 //
 //     bb2: {
-//         Retag(_17);
+//         Retag(_18);
 //         ...
-//         _21 = const Test::foo_shr(move _22, move _24) -> bb3;
+//         _22 = const Test::foo_shr(move _23, move _25) -> bb3;
 //     }
 //
 //     bb3: {
diff --git a/src/test/mir-opt/unusual-item-types.rs b/src/test/mir-opt/unusual-item-types.rs
new file mode 100644
index 0000000000000..fe85baa048e39
--- /dev/null
+++ b/src/test/mir-opt/unusual-item-types.rs
@@ -0,0 +1,66 @@
+// Test that we don't ICE when trying to dump MIR for unusual item types and
+// that we don't create filenames containing `<` and `>`
+
+struct A;
+
+impl A {
+    const ASSOCIATED_CONSTANT: i32 = 2;
+}
+
+enum E {
+    V = 5,
+}
+
+fn main() {
+    let v = Vec::<i32>::new();
+}
+
+// END RUST SOURCE
+
+// START rustc.{{impl}}-ASSOCIATED_CONSTANT.mir_map.0.mir
+// bb0: {
+//     _0 = const 2i32;
+//     return;
+// }
+// bb1: {
+//     resume;
+// }
+// END rustc.{{impl}}-ASSOCIATED_CONSTANT.mir_map.0.mir
+
+// START rustc.E-V-{{constant}}.mir_map.0.mir
+// bb0: {
+//     _0 = const 5isize;
+//     return;
+// }
+// bb1: {
+//     resume;
+// }
+// END rustc.E-V-{{constant}}.mir_map.0.mir
+
+// START rustc.ptr-real_drop_in_place.std__vec__Vec_i32_.AddMovesForPackedDrops.before.mir
+//     bb0: {
+//     goto -> bb7;
+// }
+// bb1: {
+//     return;
+// }
+// bb2: {
+//     resume;
+// }
+// bb3: {
+//     goto -> bb1;
+// }
+// bb4: {
+//     goto -> bb2;
+// }
+// bb5: {
+//     drop(((*_1).0: alloc::raw_vec::RawVec<i32>)) -> bb4;
+// }
+// bb6: {
+//     drop(((*_1).0: alloc::raw_vec::RawVec<i32>)) -> [return: bb3, unwind: bb4];
+// }
+// bb7: {
+//     _2 = &mut (*_1);
+//     _3 = const std::ops::Drop::drop(move _2) -> [return: bb6, unwind: bb5];
+// }
+// END rustc.ptr-real_drop_in_place.std__vec__Vec_i32_.AddMovesForPackedDrops.before.mir
diff --git a/src/test/pretty/dollar-crate.pp b/src/test/pretty/dollar-crate.pp
new file mode 100644
index 0000000000000..3d2d949be2b2e
--- /dev/null
+++ b/src/test/pretty/dollar-crate.pp
@@ -0,0 +1,18 @@
+#![feature(prelude_import)]
+#![no_std]
+#[prelude_import]
+use ::std::prelude::v1::*;
+#[macro_use]
+extern crate std;
+// pretty-compare-only
+// pretty-mode:expanded
+// pp-exact:dollar-crate.pp
+
+fn main() {
+    {
+        ::std::io::_print(::std::fmt::Arguments::new_v1(&["rust\n"],
+                                                        &match () {
+                                                             () => [],
+                                                         }));
+    };
+}
diff --git a/src/test/pretty/dollar-crate.rs b/src/test/pretty/dollar-crate.rs
new file mode 100644
index 0000000000000..e46bc7f4859a7
--- /dev/null
+++ b/src/test/pretty/dollar-crate.rs
@@ -0,0 +1,7 @@
+// pretty-compare-only
+// pretty-mode:expanded
+// pp-exact:dollar-crate.pp
+
+fn main() {
+    println!("rust");
+}
diff --git a/src/test/run-fail-fulldeps/qquote.rs b/src/test/run-fail-fulldeps/qquote.rs
deleted file mode 100644
index d0e0521672878..0000000000000
--- a/src/test/run-fail-fulldeps/qquote.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-// ignore-cross-compile
-
-// error-pattern:expected expression, found statement (`let`)
-
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_pos;
-
-use syntax::ast;
-use syntax::source_map;
-use syntax::print::pprust;
-use syntax::symbol::Symbol;
-use syntax_pos::DUMMY_SP;
-
-fn main() {
-    syntax::with_globals(|| run());
-}
-
-fn run() {
-    let ps = syntax::parse::ParseSess::new(source_map::FilePathMapping::empty());
-    let mut resolver = syntax::ext::base::DummyResolver;
-    let mut cx = syntax::ext::base::ExtCtxt::new(
-        &ps,
-        syntax::ext::expand::ExpansionConfig::default("qquote".to_string()),
-        &mut resolver);
-    let cx = &mut cx;
-
-    println!("{}", pprust::expr_to_string(&*quote_expr!(&cx, 23)));
-    assert_eq!(pprust::expr_to_string(&*quote_expr!(&cx, 23)), "23");
-
-    let expr = quote_expr!(&cx, let x isize = 20;);
-    println!("{}", pprust::expr_to_string(&*expr));
-    assert_eq!(pprust::expr_to_string(&*expr), "let x isize = 20;");
-}
diff --git a/src/test/run-make-fulldeps/alloc-extern-crates/Makefile b/src/test/run-make-fulldeps/alloc-extern-crates/Makefile
index 7197f4e17e3cc..338caa5614ee5 100644
--- a/src/test/run-make-fulldeps/alloc-extern-crates/Makefile
+++ b/src/test/run-make-fulldeps/alloc-extern-crates/Makefile
@@ -2,4 +2,4 @@
 
 all:
 	$(RUSTC) fakealloc.rs
-	$(RUSTC) --crate-type=rlib ../../../liballoc/lib.rs --cfg feature=\"external_crate\" --extern external=$(TMPDIR)/$(shell $(RUSTC) --print file-names fakealloc.rs)
+	$(RUSTC) --edition=2018 --crate-type=rlib ../../../liballoc/lib.rs --cfg feature=\"external_crate\" --extern external=$(TMPDIR)/$(shell $(RUSTC) --print file-names fakealloc.rs)
diff --git a/src/test/run-make-fulldeps/c-dynamic-dylib/Makefile b/src/test/run-make-fulldeps/c-dynamic-dylib/Makefile
index 83bddd4c73c3f..c524610bf5c07 100644
--- a/src/test/run-make-fulldeps/c-dynamic-dylib/Makefile
+++ b/src/test/run-make-fulldeps/c-dynamic-dylib/Makefile
@@ -1,14 +1,12 @@
 -include ../tools.mk
 
+# ignore-macos
+#
 # This hits an assertion in the linker on older versions of osx apparently
-ifeq ($(shell uname),Darwin)
-all:
-	echo ignored
-else
+
 all: $(call DYLIB,cfoo)
 	$(RUSTC) foo.rs -C prefer-dynamic
 	$(RUSTC) bar.rs
 	$(call RUN,bar)
 	$(call REMOVE_DYLIBS,cfoo)
 	$(call FAIL,bar)
-endif
diff --git a/src/test/run-make-fulldeps/c-dynamic-rlib/Makefile b/src/test/run-make-fulldeps/c-dynamic-rlib/Makefile
index e15cfd34d6c36..91343e73e1519 100644
--- a/src/test/run-make-fulldeps/c-dynamic-rlib/Makefile
+++ b/src/test/run-make-fulldeps/c-dynamic-rlib/Makefile
@@ -1,17 +1,15 @@
 -include ../tools.mk
 
+# ignore-macos
+#
+# This hits an assertion in the linker on older versions of osx apparently
+
 # This overrides the LD_LIBRARY_PATH for RUN
 TARGET_RPATH_DIR:=$(TARGET_RPATH_DIR):$(TMPDIR)
 
-# This hits an assertion in the linker on older versions of osx apparently
-ifeq ($(shell uname),Darwin)
-all:
-	echo ignored
-else
 all: $(call DYLIB,cfoo)
 	$(RUSTC) foo.rs
 	$(RUSTC) bar.rs
 	$(call RUN,bar)
 	$(call REMOVE_DYLIBS,cfoo)
 	$(call FAIL,bar)
-endif
diff --git a/src/test/run-make-fulldeps/c-link-to-rust-staticlib/Makefile b/src/test/run-make-fulldeps/c-link-to-rust-staticlib/Makefile
index 47264e82165b4..687b59ac00e8f 100644
--- a/src/test/run-make-fulldeps/c-link-to-rust-staticlib/Makefile
+++ b/src/test/run-make-fulldeps/c-link-to-rust-staticlib/Makefile
@@ -1,7 +1,8 @@
 -include ../tools.mk
 
-# FIXME: ignore freebsd
-ifneq ($(shell uname),FreeBSD)
+# ignore-freebsd
+# FIXME
+
 all:
 	$(RUSTC) foo.rs
 	$(CC) bar.c $(call STATICLIB,foo) $(call OUT_EXE,bar) \
@@ -9,8 +10,3 @@ all:
 	$(call RUN,bar)
 	rm $(call STATICLIB,foo)
 	$(call RUN,bar)
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/cdylib-fewer-symbols/Makefile b/src/test/run-make-fulldeps/cdylib-fewer-symbols/Makefile
index 1a0664dfafd7e..23491d814d01d 100644
--- a/src/test/run-make-fulldeps/cdylib-fewer-symbols/Makefile
+++ b/src/test/run-make-fulldeps/cdylib-fewer-symbols/Makefile
@@ -3,13 +3,10 @@
 
 -include ../tools.mk
 
+# ignore-windows
 # FIXME: The __rdl_ and __rust_ symbol still remains, no matter using MSVC or GNU
 # See https://github.com/rust-lang/rust/pull/46207#issuecomment-347561753
-ifdef IS_WINDOWS
-all:
-	true
-else
+
 all:
 	$(RUSTC) foo.rs
 	nm -g "$(call DYLIB,foo)" | $(CGREP) -v __rdl_ __rde_ __rg_ __rust_
-endif
diff --git a/src/test/run-make-fulldeps/compiler-rt-works-on-mingw/Makefile b/src/test/run-make-fulldeps/compiler-rt-works-on-mingw/Makefile
index 06d1bb6698ece..d7d078e56b2e7 100644
--- a/src/test/run-make-fulldeps/compiler-rt-works-on-mingw/Makefile
+++ b/src/test/run-make-fulldeps/compiler-rt-works-on-mingw/Makefile
@@ -1,17 +1,9 @@
 -include ../tools.mk
 
-ifneq (,$(findstring MINGW,$(UNAME)))
-ifndef IS_MSVC
+# only-mingw
+
 all:
 	$(CXX) foo.cpp -c -o $(TMPDIR)/foo.o
 	$(AR) crus $(TMPDIR)/libfoo.a $(TMPDIR)/foo.o
 	$(RUSTC) foo.rs -lfoo -lstdc++
 	$(call RUN,foo)
-else
-all:
-
-endif
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-clang/Makefile b/src/test/run-make-fulldeps/cross-lang-lto-clang/Makefile
new file mode 100644
index 0000000000000..b3c5fb2d79647
--- /dev/null
+++ b/src/test/run-make-fulldeps/cross-lang-lto-clang/Makefile
@@ -0,0 +1,25 @@
+# needs-matching-clang
+
+# This test makes sure that cross-language inlining actually works by checking
+# the generated machine code.
+
+-include ../tools.mk
+
+all: cpp-executable rust-executable
+
+cpp-executable:
+	$(RUSTC) -Clinker-plugin-lto=on -o $(TMPDIR)/librustlib-xlto.a -Copt-level=2 -Ccodegen-units=1 ./rustlib.rs
+	$(CLANG) -flto=thin -fuse-ld=lld -L $(TMPDIR) -lrustlib-xlto -o $(TMPDIR)/cmain ./cmain.c -O3
+	# Make sure we don't find a call instruction to the function we expect to
+	# always be inlined.
+	llvm-objdump -d $(TMPDIR)/cmain | $(CGREP) -v -e "call.*rust_always_inlined"
+	# As a sanity check, make sure we do find a call instruction to a
+	# non-inlined function
+	llvm-objdump -d $(TMPDIR)/cmain | $(CGREP) -e "call.*rust_never_inlined"
+
+rust-executable:
+	$(CLANG) ./clib.c -flto=thin -c -o $(TMPDIR)/clib.o -O2
+	(cd $(TMPDIR); $(AR) crus ./libxyz.a ./clib.o)
+	$(RUSTC) -Clinker-plugin-lto=on -L$(TMPDIR) -Copt-level=2 -Clinker=$(CLANG) -Clink-arg=-fuse-ld=lld ./main.rs -o $(TMPDIR)/rsmain
+	llvm-objdump -d $(TMPDIR)/rsmain | $(CGREP) -e "call.*c_never_inlined"
+	llvm-objdump -d $(TMPDIR)/rsmain | $(CGREP) -v -e "call.*c_always_inlined"
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-clang/clib.c b/src/test/run-make-fulldeps/cross-lang-lto-clang/clib.c
new file mode 100644
index 0000000000000..90f33f24dc424
--- /dev/null
+++ b/src/test/run-make-fulldeps/cross-lang-lto-clang/clib.c
@@ -0,0 +1,9 @@
+#include <stdint.h>
+
+uint32_t c_always_inlined() {
+    return 1234;
+}
+
+__attribute__((noinline)) uint32_t c_never_inlined() {
+    return 12345;
+}
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-clang/cmain.c b/src/test/run-make-fulldeps/cross-lang-lto-clang/cmain.c
new file mode 100644
index 0000000000000..e62a40117ce83
--- /dev/null
+++ b/src/test/run-make-fulldeps/cross-lang-lto-clang/cmain.c
@@ -0,0 +1,12 @@
+#include <stdint.h>
+
+// A trivial function defined in Rust, returning a constant value. This should
+// always be inlined.
+uint32_t rust_always_inlined();
+
+
+uint32_t rust_never_inlined();
+
+int main(int argc, char** argv) {
+    return rust_never_inlined() + rust_always_inlined();
+}
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-clang/main.rs b/src/test/run-make-fulldeps/cross-lang-lto-clang/main.rs
new file mode 100644
index 0000000000000..8129dcb85d96a
--- /dev/null
+++ b/src/test/run-make-fulldeps/cross-lang-lto-clang/main.rs
@@ -0,0 +1,11 @@
+#[link(name = "xyz")]
+extern "C" {
+    fn c_always_inlined() -> u32;
+    fn c_never_inlined() -> u32;
+}
+
+fn main() {
+    unsafe {
+        println!("blub: {}", c_always_inlined() + c_never_inlined());
+    }
+}
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-clang/rustlib.rs b/src/test/run-make-fulldeps/cross-lang-lto-clang/rustlib.rs
new file mode 100644
index 0000000000000..8a74d74a420bd
--- /dev/null
+++ b/src/test/run-make-fulldeps/cross-lang-lto-clang/rustlib.rs
@@ -0,0 +1,12 @@
+#![crate_type="staticlib"]
+
+#[no_mangle]
+pub extern "C" fn rust_always_inlined() -> u32 {
+    42
+}
+
+#[no_mangle]
+#[inline(never)]
+pub extern "C" fn rust_never_inlined() -> u32 {
+    421
+}
diff --git a/src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile b/src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile
index 0a6f226a027f3..c9da06ff93f86 100644
--- a/src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile
+++ b/src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile
@@ -1,15 +1,18 @@
-
 -include ../tools.mk
 
+# ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
+# (so fixing it is harder). See #57765 for context
+ifndef IS_WINDOWS
+
 # This test makes sure that we don't loose upstream object files when compiling
-# staticlibs with -Zcross-lang-lto
+# staticlibs with -C linker-plugin-lto
 
 all: staticlib.rs upstream.rs
-	$(RUSTC) upstream.rs -Z cross-lang-lto -Ccodegen-units=1
+	$(RUSTC) upstream.rs -C linker-plugin-lto -Ccodegen-units=1
 
 	# Check No LTO
-	$(RUSTC) staticlib.rs -Z cross-lang-lto -Ccodegen-units=1 -L. -o $(TMPDIR)/staticlib.a
-	(cd $(TMPDIR); llvm-ar x ./staticlib.a)
+	$(RUSTC) staticlib.rs -C linker-plugin-lto -Ccodegen-units=1 -L. -o $(TMPDIR)/staticlib.a
+	(cd $(TMPDIR); $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x ./staticlib.a)
 	# Make sure the upstream object file was included
 	ls $(TMPDIR)/upstream.*.rcgu.o
 
@@ -17,7 +20,13 @@ all: staticlib.rs upstream.rs
 	rm $(TMPDIR)/*
 
 	# Check ThinLTO
-	$(RUSTC) upstream.rs -Z cross-lang-lto -Ccodegen-units=1 -Clto=thin
-	$(RUSTC) staticlib.rs -Z cross-lang-lto -Ccodegen-units=1 -Clto=thin -L. -o $(TMPDIR)/staticlib.a
-	(cd $(TMPDIR); llvm-ar x ./staticlib.a)
+	$(RUSTC) upstream.rs -C linker-plugin-lto -Ccodegen-units=1 -Clto=thin
+	$(RUSTC) staticlib.rs -C linker-plugin-lto -Ccodegen-units=1 -Clto=thin -L. -o $(TMPDIR)/staticlib.a
+	(cd $(TMPDIR); $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x ./staticlib.a)
 	ls $(TMPDIR)/upstream.*.rcgu.o
+
+else
+
+all:
+
+endif
diff --git a/src/test/run-make-fulldeps/cross-lang-lto/Makefile b/src/test/run-make-fulldeps/cross-lang-lto/Makefile
index 1d072e03de307..43bd05a73592c 100644
--- a/src/test/run-make-fulldeps/cross-lang-lto/Makefile
+++ b/src/test/run-make-fulldeps/cross-lang-lto/Makefile
@@ -1,46 +1,57 @@
 
 -include ../tools.mk
 
+# ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
+# (so fixing it is harder). See #57765 for context
+ifndef IS_WINDOWS
+
 # This test makes sure that the object files we generate are actually
 # LLVM bitcode files (as used by linker LTO plugins) when compiling with
-# -Z cross-lang-lto.
+# -Clinker-plugin-lto.
 
-ASSERT_IS_BITCODE_OBJ=llvm-bcanalyzer # this only succeeds for bitcode files
-EXTRACT_OBJS=(cd $(TMPDIR); rm -f ./*.o; llvm-ar x $(1))
+# this only succeeds for bitcode files
+ASSERT_IS_BITCODE_OBJ=($(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-bcanalyzer $(1))
+EXTRACT_OBJS=(cd $(TMPDIR); rm -f ./*.o; $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x $(1))
 
-BUILD_LIB=$(RUSTC) lib.rs -Copt-level=2 -Z cross-lang-lto=on -Ccodegen-units=1
-BUILD_EXE=$(RUSTC) main.rs -Copt-level=2 -Z cross-lang-lto=on -Ccodegen-units=1 --emit=obj
+BUILD_LIB=$(RUSTC) lib.rs -Copt-level=2 -Clinker-plugin-lto -Ccodegen-units=1
+BUILD_EXE=$(RUSTC) main.rs -Copt-level=2 -Clinker-plugin-lto -Ccodegen-units=1 --emit=obj
 
 all: staticlib staticlib-fat-lto staticlib-thin-lto rlib exe cdylib rdylib
 
 staticlib: lib.rs
 	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib.a
 	$(call EXTRACT_OBJS, liblib.a)
-	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
+	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
 
 staticlib-fat-lto: lib.rs
 	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-fat-lto.a -Clto=fat
 	$(call EXTRACT_OBJS, liblib-fat-lto.a)
-	for file in $(TMPDIR)/liblib-fat-lto.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
+	for file in $(TMPDIR)/liblib-fat-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
 
 staticlib-thin-lto: lib.rs
 	$(BUILD_LIB) --crate-type=staticlib -o $(TMPDIR)/liblib-thin-lto.a -Clto=thin
 	$(call EXTRACT_OBJS, liblib-thin-lto.a)
-	for file in $(TMPDIR)/liblib-thin-lto.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
+	for file in $(TMPDIR)/liblib-thin-lto.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
 
 rlib: lib.rs
 	$(BUILD_LIB) --crate-type=rlib -o $(TMPDIR)/liblib.rlib
 	$(call EXTRACT_OBJS, liblib.rlib)
-	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(ASSERT_IS_BITCODE_OBJ) $$file; done
+	for file in $(TMPDIR)/liblib.*.rcgu.o; do $(call ASSERT_IS_BITCODE_OBJ, $$file); done
 
 cdylib: lib.rs
 	$(BUILD_LIB) --crate-type=cdylib --emit=obj -o $(TMPDIR)/cdylib.o
-	$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/cdylib.o
+	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/cdylib.o)
 
 rdylib: lib.rs
 	$(BUILD_LIB) --crate-type=dylib --emit=obj -o $(TMPDIR)/rdylib.o
-	$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/rdylib.o
+	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/rdylib.o)
 
 exe: lib.rs
 	$(BUILD_EXE) -o $(TMPDIR)/exe.o
-	$(ASSERT_IS_BITCODE_OBJ) $(TMPDIR)/exe.o
+	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/exe.o)
+
+else
+
+all:
+
+endif
diff --git a/src/test/run-make-fulldeps/dep-info-spaces/Makefile b/src/test/run-make-fulldeps/dep-info-spaces/Makefile
index 82686ffdd9d93..339a751ff96be 100644
--- a/src/test/run-make-fulldeps/dep-info-spaces/Makefile
+++ b/src/test/run-make-fulldeps/dep-info-spaces/Makefile
@@ -1,9 +1,9 @@
 -include ../tools.mk
 
-# FIXME: ignore freebsd/windows
-# (windows: see `../dep-info/Makefile`)
-ifneq ($(shell uname),FreeBSD)
-ifndef IS_WINDOWS
+# ignore-windows
+# ignore-freebsd
+# FIXME: (windows: see `../dep-info/Makefile`)
+
 all:
 	cp lib.rs $(TMPDIR)/
 	cp 'foo foo.rs' $(TMPDIR)/
@@ -17,12 +17,3 @@ all:
 	pwd
 	$(MAKE) -drf Makefile.foo
 	rm $(TMPDIR)/done && exit 1 || exit 0
-else
-all:
-
-endif
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/dep-info/Makefile b/src/test/run-make-fulldeps/dep-info/Makefile
index 9b79d1af52181..afb9db177cf03 100644
--- a/src/test/run-make-fulldeps/dep-info/Makefile
+++ b/src/test/run-make-fulldeps/dep-info/Makefile
@@ -1,11 +1,11 @@
 -include ../tools.mk
 
-# FIXME: ignore freebsd/windows
-# on windows `rustc --dep-info` produces Makefile dependency with
+# ignore-windows
+# ignore-freebsd
+# FIXME: on windows `rustc --dep-info` produces Makefile dependency with
 # windows native paths (e.g. `c:\path\to\libfoo.a`)
 # but msys make seems to fail to recognize such paths, so test fails.
-ifneq ($(shell uname),FreeBSD)
-ifndef IS_WINDOWS
+
 all:
 	cp *.rs $(TMPDIR)
 	$(RUSTC) --emit dep-info,link --crate-type=lib $(TMPDIR)/lib.rs
@@ -23,12 +23,3 @@ all:
 	rm $(TMPDIR)/bar.rs
 	cp $(TMPDIR)/lib2.rs $(TMPDIR)/lib.rs
 	$(MAKE) -drf Makefile.foo
-else
-all:
-
-endif
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/emit-stack-sizes/Makefile b/src/test/run-make-fulldeps/emit-stack-sizes/Makefile
index c2f643ce24c41..604fc4688f532 100644
--- a/src/test/run-make-fulldeps/emit-stack-sizes/Makefile
+++ b/src/test/run-make-fulldeps/emit-stack-sizes/Makefile
@@ -1,31 +1,13 @@
 -include ../tools.mk
 
+# ignore-windows
+# ignore-macos
+# min-llvm-version 6.0
+#
 # This feature only works when the output object format is ELF so we ignore
 # macOS and Windows
-ifdef IS_WINDOWS
-# Do nothing on Windows.
-all:
-	exit 0
-else ifneq (,$(filter $(TARGET),i686-apple-darwin x86_64-apple-darwin))
-# Do nothing on macOS.
-all:
-	exit 0
-else
+
 # check that the .stack_sizes section is generated
-# this test requires LLVM >= 6.0.0
-vers = $(shell $(RUSTC) -Vv)
-ifneq (,$(findstring LLVM version: 3,$(vers)))
-all:
-	exit 0
-else ifneq (,$(findstring LLVM version: 4,$(vers)))
-all:
-	exit 0
-else ifneq (,$(findstring LLVM version: 5,$(vers)))
-all:
-	exit 0
-else
 all:
 	$(RUSTC) -C opt-level=3 -Z emit-stack-sizes --emit=obj foo.rs
 	size -A $(TMPDIR)/foo.o | $(CGREP) .stack_sizes
-endif
-endif
diff --git a/src/test/run-make-fulldeps/fpic/Makefile b/src/test/run-make-fulldeps/fpic/Makefile
index 6de58c2db18d3..a3d0190eed633 100644
--- a/src/test/run-make-fulldeps/fpic/Makefile
+++ b/src/test/run-make-fulldeps/fpic/Makefile
@@ -1,13 +1,10 @@
 -include ../tools.mk
 
+# ignore-windows
+# ignore-macos
+
 # Test for #39529.
 # `-z text` causes ld to error if there are any non-PIC sections
 
-ifeq ($(UNAME),Darwin)
-all:
-else ifdef IS_WINDOWS
-all:
-else
 all:
 	$(RUSTC) hello.rs -C link-args=-Wl,-z,text
-endif
diff --git a/src/test/run-make-fulldeps/include_bytes_deps/Makefile b/src/test/run-make-fulldeps/include_bytes_deps/Makefile
index 1293695b79977..ce79cec67dc37 100644
--- a/src/test/run-make-fulldeps/include_bytes_deps/Makefile
+++ b/src/test/run-make-fulldeps/include_bytes_deps/Makefile
@@ -1,20 +1,11 @@
 -include ../tools.mk
 
-# FIXME: ignore freebsd/windows
-# on windows `rustc --dep-info` produces Makefile dependency with
+# ignore-windows
+# ignore-freebsd
+# FIXME: on windows `rustc --dep-info` produces Makefile dependency with
 # windows native paths (e.g. `c:\path\to\libfoo.a`)
 # but msys make seems to fail to recognize such paths, so test fails.
-ifneq ($(shell uname),FreeBSD)
-ifndef IS_WINDOWS
+
 all:
 	$(RUSTC) --emit dep-info main.rs
 	$(CGREP) "input.txt" "input.bin" "input.md" < $(TMPDIR)/main.d
-else
-all:
-
-endif
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile b/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
index 305e8a7ddc968..483091ad4ee8b 100644
--- a/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
+++ b/src/test/run-make-fulldeps/intrinsic-unreachable/Makefile
@@ -1,15 +1,11 @@
 -include ../tools.mk
 
-ifndef IS_WINDOWS
-# The assembly for exit-unreachable.rs should be shorter because it's missing
-# (at minimum) a return instruction.
+# ignore-windows
+#
+# Because of Windows exception handling, the code is not necessarily any shorter.
+# https://github.com/llvm-mirror/llvm/commit/64b2297786f7fd6f5fa24cdd4db0298fbf211466
 
 all:
 	$(RUSTC) -O --emit asm exit-ret.rs
 	$(RUSTC) -O --emit asm exit-unreachable.rs
 	test `wc -l < $(TMPDIR)/exit-unreachable.s` -lt `wc -l < $(TMPDIR)/exit-ret.s`
-else
-# Because of Windows exception handling, the code is not necessarily any shorter.
-# https://github.com/llvm-mirror/llvm/commit/64b2297786f7fd6f5fa24cdd4db0298fbf211466
-all:
-endif
diff --git a/src/test/run-make-fulldeps/issue-24445/Makefile b/src/test/run-make-fulldeps/issue-24445/Makefile
index 2ed971bf7d970..f7ad238af14cc 100644
--- a/src/test/run-make-fulldeps/issue-24445/Makefile
+++ b/src/test/run-make-fulldeps/issue-24445/Makefile
@@ -1,12 +1,10 @@
 -include ../tools.mk
 
-ifeq ($(UNAME),Linux)
+# only-linux
+
 all:
 	$(RUSTC) foo.rs
 	$(CC) foo.c -lfoo -L $(TMPDIR) -Wl,--gc-sections -lpthread -ldl -o $(TMPDIR)/foo
 	$(call RUN,foo)
 	$(CC) foo.c -lfoo -L $(TMPDIR) -Wl,--gc-sections -lpthread -ldl -pie -fPIC -o $(TMPDIR)/foo
 	$(call RUN,foo)
-else
-all:
-endif
diff --git a/src/test/run-make-fulldeps/issue-26006/Makefile b/src/test/run-make-fulldeps/issue-26006/Makefile
index 66aa78d538637..dd023c32ba28f 100644
--- a/src/test/run-make-fulldeps/issue-26006/Makefile
+++ b/src/test/run-make-fulldeps/issue-26006/Makefile
@@ -1,8 +1,9 @@
 -include ../tools.mk
 
+# ignore-windows
+
 OUT := $(TMPDIR)/out
 
-ifndef IS_WINDOWS
 all: time
 
 time: libc
@@ -13,6 +14,3 @@ time: libc
 libc:
 	mkdir -p $(OUT)/libc
 	$(RUSTC) in/libc/lib.rs --crate-name=libc -Cmetadata=foo -o $(OUT)/libc/liblibc.rlib
-else
-all:
-endif
diff --git a/src/test/run-make-fulldeps/issue-36710/Makefile b/src/test/run-make-fulldeps/issue-36710/Makefile
index 928bdf532df8e..dc1fbb4cefb84 100644
--- a/src/test/run-make-fulldeps/issue-36710/Makefile
+++ b/src/test/run-make-fulldeps/issue-36710/Makefile
@@ -1,21 +1,12 @@
 -include ../tools.mk
 
-ifeq (musl,$(findstring musl,$(TARGET)))
-all: skip
-else
-all: test
-endif
+# ignore-musl
 
-test: foo
+all: foo
 	$(call RUN,foo)
 
-skip:
-	echo "expected failure"
-
 foo: foo.rs $(call NATIVE_STATICLIB,foo)
 	$(RUSTC) $< -lfoo $(EXTRACXXFLAGS)
 
 $(TMPDIR)/libfoo.o: foo.cpp
 	$(call COMPILE_OBJ_CXX,$@,$<)
-
-.PHONY: all test skip
diff --git a/src/test/run-make-fulldeps/issue-37839/Makefile b/src/test/run-make-fulldeps/issue-37839/Makefile
index 8b3355b96226a..c405d5c74d7af 100644
--- a/src/test/run-make-fulldeps/issue-37839/Makefile
+++ b/src/test/run-make-fulldeps/issue-37839/Makefile
@@ -1,12 +1,8 @@
 -include ../tools.mk
 
-ifeq ($(findstring stage1,$(RUST_BUILD_STAGE)),stage1)
-# ignore stage1
-all:
+# ignore-stage1
 
-else
 all:
 	$(RUSTC) a.rs && $(RUSTC) b.rs
 	$(BARE_RUSTC) c.rs -L dependency=$(TMPDIR) --extern b=$(TMPDIR)/libb.rlib \
 		--out-dir=$(TMPDIR)
-endif
diff --git a/src/test/run-make-fulldeps/issue-37893/Makefile b/src/test/run-make-fulldeps/issue-37893/Makefile
index c7732cc2682b1..df58d4f5d9486 100644
--- a/src/test/run-make-fulldeps/issue-37893/Makefile
+++ b/src/test/run-make-fulldeps/issue-37893/Makefile
@@ -1,10 +1,6 @@
 -include ../tools.mk
 
-ifeq ($(findstring stage1,$(RUST_BUILD_STAGE)),stage1)
-# ignore stage1
-all:
+# ignore-stage1
 
-else
 all:
 	$(RUSTC) a.rs && $(RUSTC) b.rs && $(RUSTC) c.rs
-endif
diff --git a/src/test/run-make-fulldeps/issue-51671/Makefile b/src/test/run-make-fulldeps/issue-51671/Makefile
index bdb5ca8172075..3027ee578c79f 100644
--- a/src/test/run-make-fulldeps/issue-51671/Makefile
+++ b/src/test/run-make-fulldeps/issue-51671/Makefile
@@ -1,13 +1,9 @@
 -include ../tools.mk
 
-ifdef IS_WINDOWS
-# Do nothing on MSVC.
-all:
-	exit 0
-else
+# ignore-windows
+
 all:
 	$(RUSTC) --emit=obj app.rs
 	nm $(TMPDIR)/app.o | $(CGREP) rust_begin_unwind
 	nm $(TMPDIR)/app.o | $(CGREP) rust_eh_personality
 	nm $(TMPDIR)/app.o | $(CGREP) rust_oom
-endif
diff --git a/src/test/run-make-fulldeps/libs-search-path/Makefile b/src/test/run-make-fulldeps/libs-search-path/Makefile
index db0a069c3f5b6..f31036ffa1959 100644
--- a/src/test/run-make-fulldeps/libs-search-path/Makefile
+++ b/src/test/run-make-fulldeps/libs-search-path/Makefile
@@ -1,6 +1,6 @@
 -include ../tools.mk
 
-ifeq ($(if $(IS_WINDOWS),$(IS_MSVC),no),)
+# only-mingw
 
 all: empty.rs
 	cp -r $(shell cygpath -u $(shell $(RUSTC) --print sysroot)) $(TMPDIR)/sysroot
@@ -8,9 +8,3 @@ all: empty.rs
 	mkdir -p $(TMPDIR)/obj
 	mv $(TMPDIR)/sysroot/lib/rustlib/$(TARGET)/lib/crt2.o $(TMPDIR)/obj/crt2.o
 	$(RUSTC) --target $(TARGET) --sysroot $(TMPDIR)/sysroot -L$(TMPDIR)/obj -Z print-link-args empty.rs | $(CGREP) 'obj\\crt2.o'
-
-else
-
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/libs-through-symlinks/Makefile b/src/test/run-make-fulldeps/libs-through-symlinks/Makefile
index 2f425121f66a7..7c5ea7e402e56 100644
--- a/src/test/run-make-fulldeps/libs-through-symlinks/Makefile
+++ b/src/test/run-make-fulldeps/libs-through-symlinks/Makefile
@@ -1,8 +1,6 @@
 -include ../tools.mk
 
-ifdef IS_WINDOWS
-all:
-else
+# ignore-windows
 
 NAME := $(shell $(RUSTC) --print file-names foo.rs)
 
@@ -11,4 +9,3 @@ all:
 	$(RUSTC) foo.rs -o $(TMPDIR)/outdir/$(NAME)
 	ln -nsf outdir/$(NAME) $(TMPDIR)
 	RUST_LOG=rustc_metadata::loader $(RUSTC) bar.rs
-endif
diff --git a/src/test/run-make-fulldeps/linker-output-non-utf8/Makefile b/src/test/run-make-fulldeps/linker-output-non-utf8/Makefile
index 5f1577ab44dc5..3fffd1e7aa2a2 100644
--- a/src/test/run-make-fulldeps/linker-output-non-utf8/Makefile
+++ b/src/test/run-make-fulldeps/linker-output-non-utf8/Makefile
@@ -2,16 +2,16 @@
 
 # Make sure we don't ICE if the linker prints a non-UTF-8 error message.
 
-# Ignore Windows and Apple
-
+# ignore-windows
+#
 # This does not work in its current form on windows, possibly due to
 # gcc bugs or something about valid Windows paths.  See issue #29151
 # for more information.
-ifndef IS_WINDOWS
 
+# ignore-macos
+#
 # This also does not work on Apple APFS due to the filesystem requiring
 # valid UTF-8 paths.
-ifneq ($(shell uname),Darwin)
 
 # The zzz it to allow humans to tab complete or glob this thing.
 bad_dir := $(TMPDIR)/zzz$$'\xff'
@@ -21,12 +21,3 @@ all:
 	mkdir $(bad_dir)
 	mv $(TMPDIR)/liblibrary.a $(bad_dir)
 	LIBRARY_PATH=$(bad_dir) $(RUSTC) exec.rs 2>&1 | $(CGREP) this_symbol_not_defined
-else
-all:
-
-endif
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/min-global-align/Makefile b/src/test/run-make-fulldeps/min-global-align/Makefile
index 2eacc36f380d1..621027470040d 100644
--- a/src/test/run-make-fulldeps/min-global-align/Makefile
+++ b/src/test/run-make-fulldeps/min-global-align/Makefile
@@ -1,5 +1,7 @@
 -include ../tools.mk
 
+# only-linux
+
 # This tests ensure that global variables respect the target minimum alignment.
 # The three bools `STATIC_BOOL`, `STATIC_MUT_BOOL`, and `CONST_BOOL` all have
 # type-alignment of 1, but some targets require greater global alignment.
@@ -8,7 +10,6 @@ SRC = min_global_align.rs
 LL = $(TMPDIR)/min_global_align.ll
 
 all:
-ifeq ($(UNAME),Linux)
 # Most targets are happy with default alignment -- take i686 for example.
 ifeq ($(filter x86,$(LLVM_COMPONENTS)),x86)
 	$(RUSTC) --target=i686-unknown-linux-gnu --emit=llvm-ir $(SRC)
@@ -19,4 +20,3 @@ ifeq ($(filter systemz,$(LLVM_COMPONENTS)),systemz)
 	$(RUSTC) --target=s390x-unknown-linux-gnu --emit=llvm-ir $(SRC)
 	[ "$$(grep -c 'align 2' "$(LL)")" -eq "3" ]
 endif
-endif
diff --git a/src/test/run-make-fulldeps/no-integrated-as/Makefile b/src/test/run-make-fulldeps/no-integrated-as/Makefile
index 78e3025b99ad4..1567b325d4fe1 100644
--- a/src/test/run-make-fulldeps/no-integrated-as/Makefile
+++ b/src/test/run-make-fulldeps/no-integrated-as/Makefile
@@ -1,7 +1,8 @@
 -include ../tools.mk
 
+# only-linux
+# only-x86_64
+
 all:
-ifeq ($(TARGET),x86_64-unknown-linux-gnu)
 	$(RUSTC) hello.rs -C no_integrated_as
 	$(call RUN,hello)
-endif
diff --git a/src/test/run-make-fulldeps/pgo-gen-lto/Makefile b/src/test/run-make-fulldeps/pgo-gen-lto/Makefile
index 6ec2978058dfc..e358314c0d09e 100644
--- a/src/test/run-make-fulldeps/pgo-gen-lto/Makefile
+++ b/src/test/run-make-fulldeps/pgo-gen-lto/Makefile
@@ -1,10 +1,10 @@
 -include ../tools.mk
 
+# ignore-windows
+
 all:
 ifeq ($(PROFILER_SUPPORT),1)
-ifndef IS_WINDOWS
 	$(RUSTC) -Copt-level=3 -Clto=fat -Z pgo-gen="$(TMPDIR)/test.profraw" test.rs
 	$(call RUN,test) || exit 1
 	[ -e "$(TMPDIR)/test.profraw" ] || (echo "No .profraw file"; exit 1)
 endif
-endif
diff --git a/src/test/run-make-fulldeps/pgo-gen/Makefile b/src/test/run-make-fulldeps/pgo-gen/Makefile
index 96126ab7a7946..1961dff8d783e 100644
--- a/src/test/run-make-fulldeps/pgo-gen/Makefile
+++ b/src/test/run-make-fulldeps/pgo-gen/Makefile
@@ -1,10 +1,10 @@
 -include ../tools.mk
 
+# ignore-windows
+
 all:
 ifeq ($(PROFILER_SUPPORT),1)
-ifndef IS_WINDOWS
 	$(RUSTC) -g -Z pgo-gen="$(TMPDIR)/test.profraw" test.rs
 	$(call RUN,test) || exit 1
 	[ -e "$(TMPDIR)/test.profraw" ] || (echo "No .profraw file"; exit 1)
 endif
-endif
diff --git a/src/test/run-make-fulldeps/prune-link-args/Makefile b/src/test/run-make-fulldeps/prune-link-args/Makefile
index a6e219873dfd2..3589f98e7e5c8 100644
--- a/src/test/run-make-fulldeps/prune-link-args/Makefile
+++ b/src/test/run-make-fulldeps/prune-link-args/Makefile
@@ -1,11 +1,9 @@
 -include ../tools.mk
-ifdef IS_WINDOWS
-# ignore windows
-RUSTC_FLAGS =
-else
+
+# ignore-windows
+
 # Notice the space in the end, this emulates the output of pkg-config
 RUSTC_FLAGS = -C link-args="-lc "
-endif
 
 all:
 	$(RUSTC) $(RUSTC_FLAGS) empty.rs
diff --git a/src/test/run-make-fulldeps/relro-levels/Makefile b/src/test/run-make-fulldeps/relro-levels/Makefile
index 78ac2f6a82da5..aacb5acb7a3af 100644
--- a/src/test/run-make-fulldeps/relro-levels/Makefile
+++ b/src/test/run-make-fulldeps/relro-levels/Makefile
@@ -1,9 +1,10 @@
 -include ../tools.mk
 
+# only-linux
+#
 # This tests the different -Zrelro-level values, and makes sure that they work properly.
 
 all:
-ifeq ($(UNAME),Linux)
 	# Ensure that binaries built with the full relro level links them with both
 	# RELRO and BIND_NOW for doing eager symbol resolving.
 	$(RUSTC) -Zrelro-level=full hello.rs
@@ -18,4 +19,3 @@ ifeq ($(UNAME),Linux)
 	# enabled by default.
 	$(RUSTC) -Zrelro-level=off hello.rs
 	! readelf -l $(TMPDIR)/hello | grep -q GNU_RELRO
-endif
diff --git a/src/test/run-make-fulldeps/rustdoc-io-error/Makefile b/src/test/run-make-fulldeps/rustdoc-io-error/Makefile
index 2055c9cbf2da0..f95fa88d41cf7 100644
--- a/src/test/run-make-fulldeps/rustdoc-io-error/Makefile
+++ b/src/test/run-make-fulldeps/rustdoc-io-error/Makefile
@@ -4,10 +4,10 @@
 # while generating files. Ideally this would be a rustdoc-ui test, so we could
 # verify the error message as well.
 
-OUTPUT_DIR := "$(TMPDIR)/rustdoc-io-error"
+# ignore-windows
+# The test uses `chmod`.
 
-# Ignore Windows: the test uses `chmod`.
-ifndef IS_WINDOWS
+OUTPUT_DIR := "$(TMPDIR)/rustdoc-io-error"
 
 # This test operates by creating a temporary directory and modifying its
 # permissions so that it is not writable. We have to take special care to set
@@ -18,8 +18,3 @@ all:
 	-$(shell $(RUSTDOC) -o $(OUTPUT_DIR) foo.rs)
 	chmod u+w $(OUTPUT_DIR)
 	exit $($(.SHELLSTATUS) -eq 1)
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/sanitizer-leak/Makefile b/src/test/run-make-fulldeps/sanitizer-leak/Makefile
index ab43fac2e99c3..0f3c18f9293f5 100644
--- a/src/test/run-make-fulldeps/sanitizer-leak/Makefile
+++ b/src/test/run-make-fulldeps/sanitizer-leak/Makefile
@@ -1,16 +1,12 @@
 -include ../tools.mk
 
+# only-linux
+# only-x86_64
+# ignore-test
 # FIXME(#46126) ThinLTO for libstd broke this test
-ifeq (1,0)
+
 all:
-ifeq ($(TARGET),x86_64-unknown-linux-gnu)
 ifdef SANITIZER_SUPPORT
 	$(RUSTC) -C opt-level=1 -g -Z sanitizer=leak -Z print-link-args leak.rs | $(CGREP) librustc_lsan
 	$(TMPDIR)/leak 2>&1 | $(CGREP) 'detected memory leaks'
 endif
-endif
-
-else
-all:
-endif
-
diff --git a/src/test/run-make-fulldeps/sanitizer-memory/Makefile b/src/test/run-make-fulldeps/sanitizer-memory/Makefile
index 3507ca2bef2a0..718d9637ea06d 100644
--- a/src/test/run-make-fulldeps/sanitizer-memory/Makefile
+++ b/src/test/run-make-fulldeps/sanitizer-memory/Makefile
@@ -1,10 +1,10 @@
 -include ../tools.mk
 
+# only-linux
+# only-x86_64
+
 all:
-ifeq ($(TARGET),x86_64-unknown-linux-gnu)
 ifdef SANITIZER_SUPPORT
 	$(RUSTC) -g -Z sanitizer=memory -Z print-link-args uninit.rs | $(CGREP) librustc_msan
 	$(TMPDIR)/uninit 2>&1 | $(CGREP) use-of-uninitialized-value
 endif
-endif
-
diff --git a/src/test/run-make-fulldeps/static-extern-type/Makefile b/src/test/run-make-fulldeps/static-extern-type/Makefile
new file mode 100644
index 0000000000000..5879fc0ce7781
--- /dev/null
+++ b/src/test/run-make-fulldeps/static-extern-type/Makefile
@@ -0,0 +1,5 @@
+-include ../tools.mk
+
+all: $(call NATIVE_STATICLIB,define-foo)
+	$(RUSTC) -ldefine-foo use-foo.rs
+	$(call RUN,use-foo) || exit 1
diff --git a/src/test/run-make-fulldeps/static-extern-type/define-foo.c b/src/test/run-make-fulldeps/static-extern-type/define-foo.c
new file mode 100644
index 0000000000000..39be5acfa1118
--- /dev/null
+++ b/src/test/run-make-fulldeps/static-extern-type/define-foo.c
@@ -0,0 +1,11 @@
+#include <stdint.h>
+
+struct Foo {
+    uint8_t x;
+};
+
+struct Foo FOO = { 42 };
+
+uint8_t bar(const struct Foo* foo) {
+    return foo->x;
+}
diff --git a/src/test/run-make-fulldeps/static-extern-type/use-foo.rs b/src/test/run-make-fulldeps/static-extern-type/use-foo.rs
new file mode 100644
index 0000000000000..932b5b5944bc7
--- /dev/null
+++ b/src/test/run-make-fulldeps/static-extern-type/use-foo.rs
@@ -0,0 +1,14 @@
+#![feature(extern_types)]
+
+extern "C" {
+    type Foo;
+    static FOO: Foo;
+    fn bar(foo: *const Foo) -> u8;
+}
+
+fn main() {
+    unsafe {
+        let foo = &FOO;
+        assert_eq!(bar(foo), 42);
+    }
+}
diff --git a/src/test/run-make-fulldeps/symbol-visibility/Makefile b/src/test/run-make-fulldeps/symbol-visibility/Makefile
index 17d470063fc93..d99470e30d7ee 100644
--- a/src/test/run-make-fulldeps/symbol-visibility/Makefile
+++ b/src/test/run-make-fulldeps/symbol-visibility/Makefile
@@ -1,12 +1,9 @@
 include ../tools.mk
 
-ifdef IS_WINDOWS
-# Do nothing on MSVC.
+# ignore-windows
+#
 # On MINGW the --version-script, --dynamic-list, and --retain-symbol args don't
 # seem to work reliably.
-all:
-	exit 0
-else
 
 NM=nm -D
 CDYLIB_NAME=liba_cdylib.so
@@ -89,4 +86,3 @@ all:
 	# Check that an executable does not export any dynamic symbols
 	[ "$$($(NM) $(TMPDIR)/$(EXE_NAME) | grep -c public_c_function_from_rlib)" -eq "0" ]
 	[ "$$($(NM) $(TMPDIR)/$(EXE_NAME) | grep -c public_rust_function_from_exe)" -eq "0" ]
-endif
diff --git a/src/test/run-make-fulldeps/symlinked-extern/Makefile b/src/test/run-make-fulldeps/symlinked-extern/Makefile
index 88dbad51e481a..e5061fddead0b 100644
--- a/src/test/run-make-fulldeps/symlinked-extern/Makefile
+++ b/src/test/run-make-fulldeps/symlinked-extern/Makefile
@@ -1,7 +1,7 @@
 -include ../tools.mk
 
-# ignore windows: `ln` is actually `cp` on msys.
-ifndef IS_WINDOWS
+# ignore-windows
+# `ln` is actually `cp` on msys.
 
 all:
 	$(RUSTC) foo.rs
@@ -9,8 +9,3 @@ all:
 	ln -nsf $(TMPDIR)/libfoo.rlib $(TMPDIR)/other
 	$(RUSTC) bar.rs -L $(TMPDIR)
 	$(RUSTC) baz.rs --extern foo=$(TMPDIR)/other/libfoo.rlib  -L $(TMPDIR)
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/symlinked-libraries/Makefile b/src/test/run-make-fulldeps/symlinked-libraries/Makefile
index ac595546aa7c7..618ae87bfe3c5 100644
--- a/src/test/run-make-fulldeps/symlinked-libraries/Makefile
+++ b/src/test/run-make-fulldeps/symlinked-libraries/Makefile
@@ -1,15 +1,10 @@
 -include ../tools.mk
 
-# ignore windows: `ln` is actually `cp` on msys.
-ifndef IS_WINDOWS
+# ignore-windows
+# `ln` is actually `cp` on msys.
 
 all:
 	$(RUSTC) foo.rs -C prefer-dynamic
 	mkdir -p $(TMPDIR)/other
 	ln -nsf $(TMPDIR)/$(call DYLIB_GLOB,foo) $(TMPDIR)/other
 	$(RUSTC) bar.rs -L $(TMPDIR)/other
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/symlinked-rlib/Makefile b/src/test/run-make-fulldeps/symlinked-rlib/Makefile
index 2709f786e0ab2..996989ce4d893 100644
--- a/src/test/run-make-fulldeps/symlinked-rlib/Makefile
+++ b/src/test/run-make-fulldeps/symlinked-rlib/Makefile
@@ -1,14 +1,9 @@
 -include ../tools.mk
 
-# ignore windows: `ln` is actually `cp` on msys.
-ifndef IS_WINDOWS
+# ignore-windows
+# `ln` is actually `cp` on msys.
 
 all:
 	$(RUSTC) foo.rs --crate-type=rlib -o $(TMPDIR)/foo.xxx
 	ln -nsf $(TMPDIR)/foo.xxx $(TMPDIR)/libfoo.rlib
 	$(RUSTC) bar.rs -L $(TMPDIR)
-
-else
-all:
-
-endif
diff --git a/src/test/run-make-fulldeps/target-cpu-native/Makefile b/src/test/run-make-fulldeps/target-cpu-native/Makefile
index fee41461612db..d152e9f76d3d6 100644
--- a/src/test/run-make-fulldeps/target-cpu-native/Makefile
+++ b/src/test/run-make-fulldeps/target-cpu-native/Makefile
@@ -1,8 +1,11 @@
 -include ../tools.mk
 
+# only-linux
+# only-x86_64
+#
 # I *really* don't want to deal with a cross-platform way to compare file sizes,
 # tests in `make` sort of are awful
-ifeq ($(TARGET),x86_64-unknown-linux-gnu)
+
 all: $(TMPDIR)/out.log
 	# Make sure no warnings about "unknown CPU `native`" were emitted
 	if [ "$$(wc -c $(TMPDIR)/out.log | cut -d' ' -f 1)" = "0" ]; then \
@@ -10,9 +13,6 @@ all: $(TMPDIR)/out.log
 	else \
 	  exit 1; \
 	fi
-else
-all: $(TMPDIR)/out.log
-endif
 
 
 $(TMPDIR)/out.log:
diff --git a/src/test/run-make-fulldeps/use-extern-for-plugins/Makefile b/src/test/run-make-fulldeps/use-extern-for-plugins/Makefile
index cc7bc176f49f5..3976da3113190 100644
--- a/src/test/run-make-fulldeps/use-extern-for-plugins/Makefile
+++ b/src/test/run-make-fulldeps/use-extern-for-plugins/Makefile
@@ -1,8 +1,9 @@
 -include ../tools.mk
 
-SKIP_OS := 'FreeBSD OpenBSD Bitrig SunOS'
-
-ifneq ($(UNAME),$(findstring $(UNAME),$(SKIP_OS)))
+# ignore-freebsd
+# ignore-openbsd
+# ignore-bitrig
+# ignore-sunos
 
 HOST := $(shell $(RUSTC) -vV | grep 'host:' | sed 's/host: //')
 ifeq ($(findstring i686,$(HOST)),i686)
@@ -15,7 +16,3 @@ all:
 	$(RUSTC) foo.rs -C extra-filename=-host
 	$(RUSTC) bar.rs -C extra-filename=-targ --target $(TARGET)
 	$(RUSTC) baz.rs --extern a=$(TMPDIR)/liba-targ.rlib --target $(TARGET)
-else
-# FreeBSD, OpenBSD, and Bitrig support only x86_64 architecture for now
-all:
-endif
diff --git a/src/test/run-make-fulldeps/used/Makefile b/src/test/run-make-fulldeps/used/Makefile
index 47edcbb5d0a1e..8d913e3993502 100644
--- a/src/test/run-make-fulldeps/used/Makefile
+++ b/src/test/run-make-fulldeps/used/Makefile
@@ -1,11 +1,7 @@
 -include ../tools.mk
 
-ifdef IS_WINDOWS
-# Do nothing on MSVC.
-all:
-	exit 0
-else
+# ignore-windows
+
 all:
 	$(RUSTC) -C opt-level=3 --emit=obj used.rs
 	nm $(TMPDIR)/used.o | $(CGREP) FOO
-endif
diff --git a/src/test/run-make-fulldeps/windows-spawn/Makefile b/src/test/run-make-fulldeps/windows-spawn/Makefile
index f0d4242260fb5..c09ce8109e6fd 100644
--- a/src/test/run-make-fulldeps/windows-spawn/Makefile
+++ b/src/test/run-make-fulldeps/windows-spawn/Makefile
@@ -1,14 +1,8 @@
 -include ../tools.mk
 
-ifdef IS_WINDOWS
+# only-windows
 
 all:
 	$(RUSTC) -o "$(TMPDIR)/hopefullydoesntexist bar.exe" hello.rs
 	$(RUSTC) spawn.rs
 	$(TMPDIR)/spawn.exe
-
-else
-
-all:
-
-endif
diff --git a/src/test/run-make/nvptx-binary-crate/Makefile b/src/test/run-make/nvptx-binary-crate/Makefile
new file mode 100644
index 0000000000000..2c211b5c78507
--- /dev/null
+++ b/src/test/run-make/nvptx-binary-crate/Makefile
@@ -0,0 +1,12 @@
+-include ../../run-make-fulldeps/tools.mk
+
+ifeq ($(TARGET),nvptx64-nvidia-cuda)
+all:
+	$(RUSTC) main.rs --crate-type="bin" --target $(TARGET) -O -C link-arg=--arch=sm_60 -o $(TMPDIR)/main.link_arg.ptx
+	$(RUSTC) main.rs --crate-type="bin" --target $(TARGET) -O -C target-cpu=sm_60 -o $(TMPDIR)/main.target_cpu.ptx
+
+	FileCheck main.rs --input-file $(TMPDIR)/main.link_arg.ptx
+	FileCheck main.rs --input-file $(TMPDIR)/main.target_cpu.ptx
+else
+all:
+endif
diff --git a/src/test/run-make/nvptx-binary-crate/main.rs b/src/test/run-make/nvptx-binary-crate/main.rs
new file mode 100644
index 0000000000000..826bc3a47bbd6
--- /dev/null
+++ b/src/test/run-make/nvptx-binary-crate/main.rs
@@ -0,0 +1,28 @@
+#![no_std]
+#![no_main]
+#![deny(warnings)]
+#![feature(abi_ptx, core_intrinsics)]
+
+// Check the overriden CUDA arch.
+// CHECK: .target sm_60
+// CHECK: .address_size 64
+
+// Verify that no extra function declarations are present.
+// CHECK-NOT: .func
+
+// CHECK-LABEL: .visible .entry top_kernel(
+#[no_mangle]
+pub unsafe extern "ptx-kernel" fn top_kernel(a: *const u32, b: *mut u32) {
+    // CHECK: add.s32 %{{r[0-9]+}}, %{{r[0-9]+}}, 5;
+    *b = *a + 5;
+}
+
+// Verify that no extra function definitions are there.
+// CHECK-NOT: .func
+// CHECK-NOT: .entry
+
+#[panic_handler]
+unsafe fn breakpoint_panic_handler(_: &::core::panic::PanicInfo) -> ! {
+    core::intrinsics::breakpoint();
+    core::hint::unreachable_unchecked();
+}
diff --git a/src/test/run-make/nvptx-dylib-crate/Makefile b/src/test/run-make/nvptx-dylib-crate/Makefile
new file mode 100644
index 0000000000000..7284e9d1a7c99
--- /dev/null
+++ b/src/test/run-make/nvptx-dylib-crate/Makefile
@@ -0,0 +1,10 @@
+-include ../../run-make-fulldeps/tools.mk
+
+ifeq ($(TARGET),nvptx64-nvidia-cuda)
+all:
+	$(RUSTC) dep.rs --crate-type="rlib" --target $(TARGET)
+	$(RUSTC) kernel.rs --crate-type="cdylib" -O --target $(TARGET)
+	FileCheck kernel.rs --input-file $(TMPDIR)/kernel.ptx
+else
+all:
+endif
diff --git a/src/test/run-make/nvptx-dylib-crate/dep.rs b/src/test/run-make/nvptx-dylib-crate/dep.rs
new file mode 100644
index 0000000000000..57f3ee87cdb9d
--- /dev/null
+++ b/src/test/run-make/nvptx-dylib-crate/dep.rs
@@ -0,0 +1,14 @@
+#![no_std]
+#![deny(warnings)]
+
+#[inline(never)]
+#[no_mangle]
+pub fn wrapping_external_fn(a: u32) -> u32 {
+    a.wrapping_mul(a)
+}
+
+#[inline(never)]
+#[no_mangle]
+pub fn panicking_external_fn(a: u32) -> u32 {
+    a * a
+}
diff --git a/src/test/run-make/nvptx-dylib-crate/kernel.rs b/src/test/run-make/nvptx-dylib-crate/kernel.rs
new file mode 100644
index 0000000000000..63fd6b063dd8c
--- /dev/null
+++ b/src/test/run-make/nvptx-dylib-crate/kernel.rs
@@ -0,0 +1,59 @@
+#![no_std]
+#![deny(warnings)]
+#![feature(abi_ptx, core_intrinsics)]
+
+extern crate dep;
+
+// Verify the default CUDA arch.
+// CHECK: .target sm_30
+// CHECK: .address_size 64
+
+// Make sure declarations are there.
+// CHECK: .func (.param .b32 func_retval0) wrapping_external_fn
+// CHECK: .func (.param .b32 func_retval0) panicking_external_fn
+// CHECK: .func [[PANIC_HANDLER:_ZN4core9panicking5panic[a-zA-Z0-9]+]]
+
+// CHECK-LABEL: .visible .entry top_kernel(
+#[no_mangle]
+pub unsafe extern "ptx-kernel" fn top_kernel(a: *const u32, b: *mut u32) {
+    // CHECK:      call.uni (retval0),
+    // CHECK-NEXT: wrapping_external_fn
+    // CHECK:      ld.param.b32 %[[LHS:r[0-9]+]], [retval0+0];
+    let lhs = dep::wrapping_external_fn(*a);
+
+    // CHECK:      call.uni (retval0),
+    // CHECK-NEXT: panicking_external_fn
+    // CHECK:      ld.param.b32 %[[RHS:r[0-9]+]], [retval0+0];
+    let rhs = dep::panicking_external_fn(*a);
+
+    // CHECK: add.s32 %[[RES:r[0-9]+]], %[[RHS]], %[[LHS]];
+    // CHECK: st.global.u32 [%{{rd[0-9]+}}], %[[RES]];
+    *b = lhs + rhs;
+}
+
+// Verify that external function bodies are available.
+// CHECK-LABEL: .func (.param .b32 func_retval0) wrapping_external_fn
+// CHECK: {
+// CHECK:   st.param.b32 [func_retval0+0], %{{r[0-9]+}};
+// CHECK: }
+
+// Also verify panic behavior.
+// CHECK-LABEL: .func (.param .b32 func_retval0) panicking_external_fn
+// CHECK: {
+// CHECK:   %{{p[0-9]+}} bra [[PANIC_LABEL:[a-zA-Z0-9_]+]];
+// CHECK: [[PANIC_LABEL]]:
+// CHECK:   call.uni
+// CHECK:   [[PANIC_HANDLER]]
+// CHECK: }
+
+// Verify whether out dummy panic formatter has a correct body.
+// CHECK: .func [[PANIC_FMT:_ZN4core9panicking9panic_fmt[a-zA-Z0-9]+]]()
+// CHECK: {
+// CHECK:   trap;
+// CHECK: }
+
+#[panic_handler]
+unsafe fn breakpoint_panic_handler(_: &::core::panic::PanicInfo) -> ! {
+    core::intrinsics::breakpoint();
+    core::hint::unreachable_unchecked();
+}
diff --git a/src/test/run-make/nvptx-emit-asm/Makefile b/src/test/run-make/nvptx-emit-asm/Makefile
new file mode 100644
index 0000000000000..e03601878bdee
--- /dev/null
+++ b/src/test/run-make/nvptx-emit-asm/Makefile
@@ -0,0 +1,9 @@
+-include ../../run-make-fulldeps/tools.mk
+
+ifeq ($(TARGET),nvptx64-nvidia-cuda)
+all:
+	$(RUSTC) kernel.rs --crate-type="rlib" --emit asm,llvm-ir -O --target $(TARGET)
+	FileCheck kernel.rs --input-file $(TMPDIR)/kernel.s
+else
+all:
+endif
diff --git a/src/test/run-make/nvptx-emit-asm/kernel.rs b/src/test/run-make/nvptx-emit-asm/kernel.rs
new file mode 100644
index 0000000000000..b71e18d910391
--- /dev/null
+++ b/src/test/run-make/nvptx-emit-asm/kernel.rs
@@ -0,0 +1,41 @@
+#![no_std]
+#![deny(warnings)]
+#![feature(abi_ptx)]
+
+// Verify the default CUDA arch.
+// CHECK: .target sm_30
+// CHECK: .address_size 64
+
+// Verify function name doesn't contain unacceaptable characters.
+// CHECK: .func (.param .b32 func_retval0) [[IMPL_FN:_ZN[a-zA-Z0-9$_]+square[a-zA-Z0-9$_]+]]
+
+// CHECK-LABEL: .visible .entry top_kernel(
+#[no_mangle]
+pub unsafe extern "ptx-kernel" fn top_kernel(a: *const u32, b: *mut u32) {
+    // CHECK:      call.uni (retval0),
+    // CHECK-NEXT: [[IMPL_FN]]
+    *b = deep::private::MyStruct::new(*a).square();
+}
+
+pub mod deep {
+    pub mod private {
+        pub struct MyStruct<T>(T);
+
+        impl MyStruct<u32> {
+            pub fn new(a: u32) -> Self {
+                MyStruct(a)
+            }
+
+            #[inline(never)]
+            pub fn square(&self) -> u32 {
+                self.0.wrapping_mul(self.0)
+            }
+        }
+    }
+}
+
+// Verify that external function bodies are available.
+// CHECK: .func (.param .b32 func_retval0) [[IMPL_FN]]
+// CHECK: {
+// CHECK:   mul.lo.s32 %{{r[0-9]+}}, %{{r[0-9]+}}, %{{r[0-9]+}}
+// CHECK: }
diff --git a/src/test/run-make/thumb-none-cortex-m/Makefile b/src/test/run-make/thumb-none-cortex-m/Makefile
index 819439069eaed..6791c8ccdf138 100644
--- a/src/test/run-make/thumb-none-cortex-m/Makefile
+++ b/src/test/run-make/thumb-none-cortex-m/Makefile
@@ -10,8 +10,10 @@
 # - thumbv7em-none-eabihf (Bare Cortex-M4F, M7F, FPU, hardfloat)
 # - thumbv7m-none-eabi (Bare Cortex-M3)
 
-# See https://stackoverflow.com/questions/7656425/makefile-ifeq-logical-or
-ifneq (,$(filter $(TARGET),thumbv6m-none-eabi thumbv7em-none-eabi thumbv7em-none-eabihf thumbv7m-none-eabi))
+# only-thumbv6m-none-eabi
+# only-thumbv7em-none-eabi
+# only-thumbv7em-none-eabihf
+# only-thumbv7m-none-eabi
 
 # For cargo setting
 RUSTC := $(RUSTC_ORIGINAL)
@@ -36,8 +38,3 @@ all:
 	# These come from the top-level Rust workspace, that this crate is not a
 	# member of, but Cargo tries to load the workspace `Cargo.toml` anyway.
 	cd $(WORK_DIR) && cd $(CRATE) && env RUSTC_BOOTSTRAP=1 $(CARGO) build --target $(TARGET) -v
-else
-
-all:
-
-endif
diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index ffd17721b73bb..cb1ff8591221e 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -1,11 +1,12 @@
 -include ../../run-make-fulldeps/tools.mk
 
+# only-thumbv7m-none-eabi
+# only-thumbv6m-none-eabi
+
 # How to run this
 # $ ./x.py clean
 # $ ./x.py test --target thumbv7m-none-eabi src/test/run-make
 
-ifneq (,$(filter $(TARGET),thumbv6m-none-eabi thumbv7m-none-eabi))
-
 # For cargo setting
 export RUSTC := $(RUSTC_ORIGINAL)
 export LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
@@ -25,6 +26,3 @@ unexport CXX
 
 all:
 	bash script.sh
-else
-all:
-endif
diff --git a/src/test/run-make/wasm-custom-section/Makefile b/src/test/run-make/wasm-custom-section/Makefile
index 399951e516314..7c64dc58bf791 100644
--- a/src/test/run-make/wasm-custom-section/Makefile
+++ b/src/test/run-make/wasm-custom-section/Makefile
@@ -1,10 +1,8 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown
 	$(RUSTC) bar.rs -C lto -O --target wasm32-unknown-unknown
 	$(NODE) foo.js $(TMPDIR)/bar.wasm
-else
-all:
-endif
diff --git a/src/test/run-make/wasm-custom-sections-opt/Makefile b/src/test/run-make/wasm-custom-sections-opt/Makefile
index 63644c513c30d..fec7643d20c53 100644
--- a/src/test/run-make/wasm-custom-sections-opt/Makefile
+++ b/src/test/run-make/wasm-custom-sections-opt/Makefile
@@ -1,9 +1,7 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) foo.rs -O --target wasm32-unknown-unknown
 	$(NODE) foo.js $(TMPDIR)/foo.wasm
-else
-all:
-endif
diff --git a/src/test/run-make/wasm-export-all-symbols/Makefile b/src/test/run-make/wasm-export-all-symbols/Makefile
index 07379b7624413..039481215f0a6 100644
--- a/src/test/run-make/wasm-export-all-symbols/Makefile
+++ b/src/test/run-make/wasm-export-all-symbols/Makefile
@@ -1,6 +1,7 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) bar.rs --target wasm32-unknown-unknown
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown
@@ -10,7 +11,3 @@ all:
 	$(NODE) verify.js $(TMPDIR)/foo.wasm
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown -C lto
 	$(NODE) verify.js $(TMPDIR)/foo.wasm
-else
-all:
-endif
-
diff --git a/src/test/run-make/wasm-import-module/Makefile b/src/test/run-make/wasm-import-module/Makefile
index 399951e516314..255d8f1ef0e63 100644
--- a/src/test/run-make/wasm-import-module/Makefile
+++ b/src/test/run-make/wasm-import-module/Makefile
@@ -1,10 +1,8 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+ # only-wasm32
+
 all:
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown
 	$(RUSTC) bar.rs -C lto -O --target wasm32-unknown-unknown
 	$(NODE) foo.js $(TMPDIR)/bar.wasm
-else
-all:
-endif
diff --git a/src/test/run-make/wasm-panic-small/Makefile b/src/test/run-make/wasm-panic-small/Makefile
index 48b530c995725..b9141f93d538c 100644
--- a/src/test/run-make/wasm-panic-small/Makefile
+++ b/src/test/run-make/wasm-panic-small/Makefile
@@ -1,6 +1,7 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) foo.rs -C lto -O --target wasm32-unknown-unknown --cfg a
 	wc -c < $(TMPDIR)/foo.wasm
@@ -14,7 +15,3 @@ all:
 	$(RUSTC) foo.rs -C lto -O --target wasm32-unknown-unknown --cfg d
 	wc -c < $(TMPDIR)/foo.wasm
 	[ "`wc -c < $(TMPDIR)/foo.wasm`" -lt "5120" ]
-else
-all:
-endif
-
diff --git a/src/test/run-make/wasm-stringify-ints-small/Makefile b/src/test/run-make/wasm-stringify-ints-small/Makefile
new file mode 100644
index 0000000000000..26de6a0c68990
--- /dev/null
+++ b/src/test/run-make/wasm-stringify-ints-small/Makefile
@@ -0,0 +1,10 @@
+-include ../../run-make-fulldeps/tools.mk
+
+ifeq ($(TARGET),wasm32-unknown-unknown)
+all:
+	$(RUSTC) foo.rs -C lto -O --target wasm32-unknown-unknown
+	wc -c < $(TMPDIR)/foo.wasm
+	[ "`wc -c < $(TMPDIR)/foo.wasm`" -lt "20500" ]
+else
+all:
+endif
diff --git a/src/test/run-make/wasm-stringify-ints-small/foo.rs b/src/test/run-make/wasm-stringify-ints-small/foo.rs
new file mode 100644
index 0000000000000..7a947f013ad48
--- /dev/null
+++ b/src/test/run-make/wasm-stringify-ints-small/foo.rs
@@ -0,0 +1,33 @@
+#![crate_type = "cdylib"]
+
+extern "C" {
+    fn observe(ptr: *const u8, len: usize);
+}
+
+macro_rules! s {
+    ( $( $f:ident -> $t:ty );* $(;)* ) => {
+        $(
+            extern "C" {
+                fn $f() -> $t;
+            }
+            let s = $f().to_string();
+            observe(s.as_ptr(), s.len());
+        )*
+    };
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn foo() {
+    s! {
+        get_u8 -> u8;
+        get_i8 -> i8;
+        get_u16 -> u16;
+        get_i16 -> i16;
+        get_u32 -> u32;
+        get_i32 -> i32;
+        get_u64 -> u64;
+        get_i64 -> i64;
+        get_usize -> usize;
+        get_isize -> isize;
+    }
+}
diff --git a/src/test/run-make/wasm-symbols-not-exported/Makefile b/src/test/run-make/wasm-symbols-not-exported/Makefile
index 872825113a845..b17e04b771773 100644
--- a/src/test/run-make/wasm-symbols-not-exported/Makefile
+++ b/src/test/run-make/wasm-symbols-not-exported/Makefile
@@ -1,6 +1,7 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown
 	$(NODE) verify-exported-symbols.js $(TMPDIR)/foo.wasm
@@ -10,7 +11,3 @@ all:
 	$(NODE) verify-exported-symbols.js $(TMPDIR)/bar.wasm
 	$(RUSTC) bar.rs --target wasm32-unknown-unknown -O
 	$(NODE) verify-exported-symbols.js $(TMPDIR)/bar.wasm
-else
-all:
-endif
-
diff --git a/src/test/run-make/wasm-symbols-not-imported/Makefile b/src/test/run-make/wasm-symbols-not-imported/Makefile
index 773e32a031588..b8f64e06f31ef 100644
--- a/src/test/run-make/wasm-symbols-not-imported/Makefile
+++ b/src/test/run-make/wasm-symbols-not-imported/Makefile
@@ -1,6 +1,7 @@
 -include ../../run-make-fulldeps/tools.mk
 
-ifeq ($(TARGET),wasm32-unknown-unknown)
+# only-wasm32
+
 all:
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown
 	$(NODE) verify-no-imports.js $(TMPDIR)/foo.wasm
@@ -10,7 +11,3 @@ all:
 	$(NODE) verify-no-imports.js $(TMPDIR)/foo.wasm
 	$(RUSTC) foo.rs --target wasm32-unknown-unknown -O -C lto
 	$(NODE) verify-no-imports.js $(TMPDIR)/foo.wasm
-else
-all:
-endif
-
diff --git a/src/test/run-pass-fulldeps/auxiliary/issue-16723.rs b/src/test/run-pass-fulldeps/auxiliary/issue-16723.rs
deleted file mode 100644
index 76680f5dda240..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/issue-16723.rs
+++ /dev/null
@@ -1,29 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar, quote, rustc_private)]
-#![crate_type = "dylib"]
-
-extern crate syntax;
-extern crate rustc;
-extern crate rustc_data_structures;
-extern crate rustc_plugin;
-#[macro_use] extern crate smallvec;
-extern crate syntax_pos;
-
-use smallvec::SmallVec;
-use syntax::ext::base::{ExtCtxt, MacResult, MacEager};
-use syntax::tokenstream;
-use rustc_plugin::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("multiple_items", expand)
-}
-
-fn expand(cx: &mut ExtCtxt, _: syntax_pos::Span, _: &[tokenstream::TokenTree])
-          -> Box<MacResult+'static> {
-    MacEager::items(smallvec![
-        quote_item!(cx, struct Struct1;).unwrap(),
-        quote_item!(cx, struct Struct2;).unwrap()
-    ])
-}
diff --git a/src/test/run-pass-fulldeps/auxiliary/issue-40001-plugin.rs b/src/test/run-pass-fulldeps/auxiliary/issue-40001-plugin.rs
index 3e0e4e60e0db8..efa3de9a686b8 100644
--- a/src/test/run-pass-fulldeps/auxiliary/issue-40001-plugin.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/issue-40001-plugin.rs
@@ -32,6 +32,10 @@ declare_lint!(MISSING_WHITELISTED_ATTR, Deny,
 struct MissingWhitelistedAttrPass;
 
 impl LintPass for MissingWhitelistedAttrPass {
+    fn name(&self) -> &'static str {
+        "MissingWhitelistedAttrPass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(MISSING_WHITELISTED_ATTR)
     }
diff --git a/src/test/run-pass-fulldeps/auxiliary/lint_for_crate.rs b/src/test/run-pass-fulldeps/auxiliary/lint_for_crate.rs
index b6c517f2764bd..f34e10218d455 100644
--- a/src/test/run-pass-fulldeps/auxiliary/lint_for_crate.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/lint_for_crate.rs
@@ -17,6 +17,10 @@ macro_rules! fake_lint_pass {
         struct $struct;
 
         impl LintPass for $struct {
+            fn name(&self) -> &'static str {
+                stringify!($struct)
+            }
+
             fn get_lints(&self) -> LintArray {
                 $lints
             }
diff --git a/src/test/run-pass-fulldeps/auxiliary/macro_crate_test.rs b/src/test/run-pass-fulldeps/auxiliary/macro_crate_test.rs
index e31628782dc47..a2b1d6976d0eb 100644
--- a/src/test/run-pass-fulldeps/auxiliary/macro_crate_test.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/macro_crate_test.rs
@@ -1,209 +1,34 @@
 // force-host
+// no-prefer-dynamic
 
-#![feature(plugin_registrar, quote, rustc_private)]
+#![crate_type = "proc-macro"]
+#![feature(rustc_private)]
 
 extern crate syntax;
 extern crate rustc;
 extern crate rustc_plugin;
 extern crate syntax_pos;
-
-use syntax::ast::{self, Item, MetaItem, ItemKind};
-use syntax::source_map::DUMMY_SP;
-use syntax::ext::base::*;
-use syntax::ext::quote::rt::ToTokens;
-use syntax::parse::{self, token};
-use syntax::ptr::P;
-use syntax::symbol::Symbol;
-use syntax::tokenstream::TokenTree;
-use syntax_pos::Span;
-use rustc_plugin::Registry;
-
-#[macro_export]
-macro_rules! exported_macro { () => (2) }
-macro_rules! unexported_macro { () => (3) }
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("make_a_1", expand_make_a_1);
-    reg.register_macro("identity", expand_identity);
-    reg.register_syntax_extension(
-        Symbol::intern("rustc_into_multi_foo"),
-        MultiModifier(Box::new(expand_into_foo_multi)));
-    reg.register_syntax_extension(
-        Symbol::intern("rustc_duplicate"),
-        MultiDecorator(Box::new(expand_duplicate)));
-    reg.register_syntax_extension(
-        Symbol::intern("rustc_caller"),
-        MultiDecorator(Box::new(expand_caller)));
-}
-
-fn expand_make_a_1(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree]) -> Box<MacResult + 'static> {
-    if !tts.is_empty() {
-        cx.span_fatal(sp, "make_a_1 takes no arguments");
-    }
-    MacEager::expr(quote_expr!(cx, 1))
-}
-
-// See Issue #15750
-fn expand_identity(cx: &mut ExtCtxt, _span: Span, tts: &[TokenTree]) -> Box<MacResult + 'static> {
-    // Parse an expression and emit it unchanged.
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), tts.to_vec());
-    let expr = parser.parse_expr().unwrap();
-    MacEager::expr(quote_expr!(&mut *cx, $expr))
-}
-
-fn expand_into_foo_multi(cx: &mut ExtCtxt,
-                         _sp: Span,
-                         _attr: &MetaItem,
-                         it: Annotatable)
-                         -> Vec<Annotatable> {
-    match it {
-        Annotatable::Item(it) => vec![
-            Annotatable::Item(P(Item {
-                attrs: it.attrs.clone(),
-                ..(*quote_item!(cx, enum Foo2 { Bar2, Baz2 }).unwrap()).clone()
-            })),
-            Annotatable::Item(quote_item!(cx, enum Foo3 { Bar }).unwrap()),
-            Annotatable::Item(quote_item!(cx, #[cfg(any())] fn foo2() {}).unwrap()),
-        ],
-        Annotatable::ImplItem(_it) => vec![
-            quote_item!(cx, impl X { fn foo(&self) -> i32 { 42 } }).unwrap().and_then(|i| {
-                match i.node {
-                    ItemKind::Impl(.., mut items) => {
-                        Annotatable::ImplItem(P(items.pop().expect("impl method not found")))
-                    }
-                    _ => unreachable!("impl parsed to something other than impl")
-                }
-            })
-        ],
-        Annotatable::TraitItem(_it) => vec![
-            quote_item!(cx, trait X { fn foo(&self) -> i32 { 0 } }).unwrap().and_then(|i| {
-                match i.node {
-                    ItemKind::Trait(.., mut items) => {
-                        Annotatable::TraitItem(P(items.pop().expect("trait method not found")))
-                    }
-                    _ => unreachable!("trait parsed to something other than trait")
-                }
-            })
-        ],
-        // covered in proc_macro/macros-in-extern.rs
-        Annotatable::ForeignItem(..) => unimplemented!(),
-        // covered in proc_macro/attr-stmt-expr.rs
-        Annotatable::Stmt(_) | Annotatable::Expr(_) => panic!("expected item"),
-    }
+extern crate proc_macro;
+
+use proc_macro::{TokenTree, TokenStream};
+
+#[proc_macro_attribute]
+pub fn rustc_duplicate(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let mut new_name = Some(attr.into_iter().nth(0).unwrap());
+    let mut encountered_idents = 0;
+    let input = item.to_string();
+    let ret = item.into_iter().map(move |token| match token {
+        TokenTree::Ident(_) if encountered_idents == 1 => {
+            encountered_idents += 1;
+            new_name.take().unwrap()
+        }
+        TokenTree::Ident(_) => {
+            encountered_idents += 1;
+            token
+        }
+        _ => token
+    }).collect::<TokenStream>();
+    let mut input_again = input.parse::<TokenStream>().unwrap();
+    input_again.extend(ret);
+    input_again
 }
-
-// Create a duplicate of the annotatable, based on the MetaItem
-fn expand_duplicate(cx: &mut ExtCtxt,
-                    _sp: Span,
-                    mi: &MetaItem,
-                    it: &Annotatable,
-                    push: &mut FnMut(Annotatable)) {
-    let copy_name = match mi.node {
-        ast::MetaItemKind::List(ref xs) => {
-            if let Some(word) = xs[0].word() {
-                word.ident.segments.last().unwrap().ident
-            } else {
-                cx.span_err(mi.span, "Expected word");
-                return;
-            }
-        }
-        _ => {
-            cx.span_err(mi.span, "Expected list");
-            return;
-        }
-    };
-
-    // Duplicate the item but replace its ident by the MetaItem
-    match it.clone() {
-        Annotatable::Item(it) => {
-            let mut new_it = (*it).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::Item(P(new_it)));
-        }
-        Annotatable::ImplItem(it) => {
-            let mut new_it = (*it).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::ImplItem(P(new_it)));
-        }
-        Annotatable::TraitItem(tt) => {
-            let mut new_it = (*tt).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::TraitItem(P(new_it)));
-        }
-        // covered in proc_macro/macros-in-extern.rs
-        Annotatable::ForeignItem(..) => unimplemented!(),
-        // covered in proc_macro/attr-stmt-expr.rs
-        Annotatable::Stmt(_) | Annotatable::Expr(_) => panic!("expected item")
-    }
-}
-
-pub fn token_separate<T: ToTokens>(ecx: &ExtCtxt, things: &[T],
-                                   token: token::Token) -> Vec<TokenTree> {
-    let mut output: Vec<TokenTree> = vec![];
-    for (i, thing) in things.iter().enumerate() {
-        output.extend(thing.to_tokens(ecx));
-        if i < things.len() - 1 {
-            output.push(TokenTree::Token(DUMMY_SP, token.clone()));
-        }
-    }
-
-    output
-}
-
-fn expand_caller(cx: &mut ExtCtxt,
-                 sp: Span,
-                 mi: &MetaItem,
-                 it: &Annotatable,
-                 push: &mut FnMut(Annotatable)) {
-    let (orig_fn_name, ret_type) = match *it {
-        Annotatable::Item(ref item) => match item.node {
-            ItemKind::Fn(ref decl, ..) => {
-                (item.ident, &decl.output)
-            }
-            _ => cx.span_fatal(item.span, "Only functions with return types can be annotated.")
-        },
-        _ => cx.span_fatal(sp, "Only functions can be annotated.")
-    };
-
-    let (caller_name, arguments) = if let Some(list) = mi.meta_item_list() {
-        if list.len() < 2 {
-            cx.span_fatal(mi.span(), "Need a function name and at least one parameter.");
-        }
-
-        let fn_name = match list[0].name() {
-            Some(name) => ast::Ident::with_empty_ctxt(name),
-            None => cx.span_fatal(list[0].span(), "First parameter must be an ident.")
-        };
-
-        (fn_name, &list[1..])
-    } else {
-        cx.span_fatal(mi.span, "Expected list.");
-    };
-
-    let literals: Vec<ast::Lit> = arguments.iter().map(|arg| {
-        if let Some(lit) = arg.literal() {
-            lit.clone()
-        } else {
-            cx.span_fatal(arg.span(), "Expected literal.");
-        }
-    }).collect();
-
-    let arguments = token_separate(cx, literals.as_slice(), token::Comma);
-    if let ast::FunctionRetTy::Ty(ref rt) = *ret_type {
-        push(Annotatable::Item(quote_item!(cx,
-                                           fn $caller_name() -> $rt {
-                                               $orig_fn_name($arguments)
-                                           }).unwrap()))
-    } else {
-        push(Annotatable::Item(quote_item!(cx,
-                                           fn $caller_name() {
-                                               $orig_fn_name($arguments)
-                                           }).unwrap()))
-    }
-}
-
-pub fn foo() {}
diff --git a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
index eab612c5dfb45..309acb25184a8 100644
--- a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
@@ -43,7 +43,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
         NormalTT {
             expander: Box::new(Expander { args: args, }),
             def_info: None,
-            allow_internal_unstable: false,
+            allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
             unstable_feature: None,
diff --git a/src/test/run-pass-fulldeps/auxiliary/plugin_with_plugin_lib.rs b/src/test/run-pass-fulldeps/auxiliary/plugin_with_plugin_lib.rs
deleted file mode 100644
index 320b77e8ea8e1..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/plugin_with_plugin_lib.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar, rustc_private)]
-#![deny(plugin_as_library)] // should have no effect in a plugin crate
-
-extern crate macro_crate_test;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use rustc_plugin::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(_: &mut Registry) { }
diff --git a/src/test/run-pass-fulldeps/auxiliary/procedural_mbe_matching.rs b/src/test/run-pass-fulldeps/auxiliary/procedural_mbe_matching.rs
deleted file mode 100644
index e2fa3744ad8fe..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/procedural_mbe_matching.rs
+++ /dev/null
@@ -1,82 +0,0 @@
-// force-host
-
-#![crate_type="dylib"]
-#![feature(plugin_registrar, quote, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use syntax::feature_gate::Features;
-use syntax::parse::token::{NtExpr, NtPat};
-use syntax::ast::{Ident, Pat, NodeId};
-use syntax::tokenstream::{TokenTree};
-use syntax::ext::base::{ExtCtxt, MacResult, MacEager};
-use syntax::ext::build::AstBuilder;
-use syntax::ext::tt::quoted;
-use syntax::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
-use syntax::ext::tt::macro_parser::{Success, Failure, Error};
-use syntax::ext::tt::macro_parser::parse_failure_msg;
-use syntax::ptr::P;
-use syntax_pos::{Span, edition::Edition};
-use rustc_plugin::Registry;
-
-fn expand_mbe_matches(cx: &mut ExtCtxt, _: Span, args: &[TokenTree])
-        -> Box<MacResult + 'static> {
-
-    let mbe_matcher = quote_tokens!(cx, $$matched:expr, $$($$pat:pat)|+);
-    let mbe_matcher = quoted::parse(mbe_matcher.into_iter().collect(),
-                                    true,
-                                    cx.parse_sess,
-                                    &Features::new(),
-                                    &[],
-                                    Edition::Edition2015,
-                                    // not used...
-                                    NodeId::from_u32(0));
-    let map = match TokenTree::parse(cx, &mbe_matcher, args.iter().cloned().collect()) {
-        Success(map) => map,
-        Failure(_, tok, msg) => {
-            panic!("expected Success, but got Failure: {} - {}", parse_failure_msg(tok), msg);
-        }
-        Error(_, s) => {
-            panic!("expected Success, but got Error: {}", s);
-        }
-    };
-
-    let matched_nt = match *map[&Ident::from_str("matched")] {
-        MatchedNonterminal(ref nt) => nt.clone(),
-        _ => unreachable!(),
-    };
-
-    let mac_expr = match (&*matched_nt, &*map[&Ident::from_str("pat")]) {
-        (&NtExpr(ref matched_expr), &MatchedSeq(ref pats, seq_sp)) => {
-            let pats: Vec<P<Pat>> = pats.iter().map(|pat_nt| {
-                match *pat_nt {
-                    MatchedNonterminal(ref nt) => match **nt {
-                        NtPat(ref pat) => pat.clone(),
-                        _ => unreachable!(),
-                    },
-                    _ => unreachable!(),
-                }
-            }).collect();
-            let span = seq_sp.entire();
-            let arm = cx.arm(span, pats, cx.expr_bool(span, true));
-
-            quote_expr!(cx,
-                match $matched_expr {
-                    $arm
-                    _ => false
-                }
-            )
-        }
-        _ => unreachable!()
-    };
-
-    MacEager::expr(mac_expr)
-}
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("matches", expand_mbe_matches);
-}
diff --git a/src/test/run-pass-fulldeps/auxiliary/syntax_extension_with_dll_deps_2.rs b/src/test/run-pass-fulldeps/auxiliary/syntax_extension_with_dll_deps_2.rs
deleted file mode 100644
index a356df55b3562..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/syntax_extension_with_dll_deps_2.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// force-host
-
-#![crate_type = "dylib"]
-#![feature(plugin_registrar, quote, rustc_private)]
-
-extern crate syntax_extension_with_dll_deps_1 as other;
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use syntax::ast::{Item, MetaItem};
-use syntax::ext::base::*;
-use syntax::tokenstream::TokenTree;
-use syntax_pos::Span;
-use rustc_plugin::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("foo", expand_foo);
-}
-
-fn expand_foo(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree])
-              -> Box<MacResult+'static> {
-    let answer = other::the_answer();
-    MacEager::expr(quote_expr!(cx, $answer))
-}
diff --git a/src/test/run-pass-fulldeps/issue-16723.rs b/src/test/run-pass-fulldeps/issue-16723.rs
deleted file mode 100644
index a3965f98927f9..0000000000000
--- a/src/test/run-pass-fulldeps/issue-16723.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-// ignore-stage1
-// aux-build:issue-16723.rs
-#![feature(plugin)]
-#![plugin(issue_16723)]
-
-multiple_items!();
-
-impl Struct1 {
-    fn foo() {}
-}
-impl Struct2 {
-    fn foo() {}
-}
-
-fn main() {
-    Struct1::foo();
-    Struct2::foo();
-    println!("hallo");
-}
diff --git a/src/test/run-pass-fulldeps/issue-16992.rs b/src/test/run-pass-fulldeps/issue-16992.rs
deleted file mode 100644
index e5945b679f382..0000000000000
--- a/src/test/run-pass-fulldeps/issue-16992.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-// ignore-cross-compile
-
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-
-use syntax::ext::base::ExtCtxt;
-
-#[allow(dead_code)]
-fn foobar(cx: &mut ExtCtxt) {
-    quote_expr!(cx, 1);
-    quote_expr!(cx, 2);
-}
-
-fn main() { }
diff --git a/src/test/run-pass-fulldeps/issue-18763-quote-token-tree.rs b/src/test/run-pass-fulldeps/issue-18763-quote-token-tree.rs
deleted file mode 100644
index 9fa3d3de8f22e..0000000000000
--- a/src/test/run-pass-fulldeps/issue-18763-quote-token-tree.rs
+++ /dev/null
@@ -1,22 +0,0 @@
-#![allow(dead_code)]
-#![allow(unused_imports)]
-// ignore-cross-compile
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-
-use syntax::ext::base::ExtCtxt;
-
-fn syntax_extension(cx: &ExtCtxt) {
-    let _toks_1 = vec![quote_tokens!(cx, /** comment */ fn foo() {})];
-    let name = quote_tokens!(cx, bar);
-    let _toks_2 = vec![quote_item!(cx, static $name:isize = 2;)];
-    let _toks_4 = quote_tokens!(cx, $name:static $name:sizeof);
-    let _toks_3 = vec![quote_item!(cx,
-        /// comment
-        fn foo() { let $name:isize = 3; }
-    )];
-}
-
-fn main() {
-}
diff --git a/src/test/run-pass-fulldeps/macro-crate-does-hygiene-work.rs b/src/test/run-pass-fulldeps/macro-crate-does-hygiene-work.rs
deleted file mode 100644
index 3c251cc0f553a..0000000000000
--- a/src/test/run-pass-fulldeps/macro-crate-does-hygiene-work.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-
-// Issue #15750: a macro that internally parses its input and then
-// uses `quote_expr!` to rearrange it should be hygiene-preserving.
-
-#![feature(plugin)]
-#![plugin(macro_crate_test)]
-
-fn main() {
-    let x = 3;
-    assert_eq!(3, identity!(x));
-    assert_eq!(6, identity!(x+x));
-    let x = 4;
-    assert_eq!(4, identity!(x));
-}
diff --git a/src/test/run-pass-fulldeps/macro-crate-multi-decorator-literals.rs b/src/test/run-pass-fulldeps/macro-crate-multi-decorator-literals.rs
deleted file mode 100644
index eb7ab139d647f..0000000000000
--- a/src/test/run-pass-fulldeps/macro-crate-multi-decorator-literals.rs
+++ /dev/null
@@ -1,50 +0,0 @@
-#![allow(plugin_as_library)]
-#![allow(unused_imports)]
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-
-#![feature(plugin, rustc_attrs)]
-#![plugin(macro_crate_test)]
-
-#[macro_use]
-#[no_link]
-extern crate macro_crate_test;
-
-// The `caller(name, args...)` attribute emits a new nullary function named
-// `name` that calls the annotated function with `args`. As an example, consider
-// the following:
-//
-//     #[caller(simple, 1, "hello", 3.14)]
-//     fn f(num: isize, string: &'static str, float: f32) -> (isize, &'static str, float) {
-//         (num, string, float)
-//     }
-//
-// This results in a function named `simple` that calls `f(1, "hello", 3.14)`.
-// As a result, the expression `simple()` evaluates to `(1, "helllo", 3.14)`.
-
-#[rustc_caller(simple, 1, "hello", 3.14)]
-#[rustc_caller(simple1, 2, "bye", 6.28)]
-#[rustc_caller(simple2, 3, "hi", 1.01)]
-fn f(num: isize, string: &'static str, float: f32) -> (isize, &'static str, f32) {
-    (num, string, float)
-}
-
-#[rustc_caller(complex, true, 10)]
-#[rustc_caller(complex1, false, 15)]
-#[rustc_caller(complex2, true, 20)]
-fn g(emit: bool, num: i32) -> Option<i32> {
-    match emit {
-        true => Some(num),
-        false => None
-    }
-}
-
-fn main() {
-    assert_eq!(simple(), (1, "hello", 3.14));
-    assert_eq!(simple1(), (2, "bye", 6.28));
-    assert_eq!(simple2(), (3, "hi", 1.01));
-
-    assert_eq!(complex(), Some(10));
-    assert_eq!(complex1(), None);
-    assert_eq!(complex2(), Some(20));
-}
diff --git a/src/test/run-pass-fulldeps/macro-crate-multi-decorator.rs b/src/test/run-pass-fulldeps/macro-crate-multi-decorator.rs
index ef28f233feaa1..dcac160c4c974 100644
--- a/src/test/run-pass-fulldeps/macro-crate-multi-decorator.rs
+++ b/src/test/run-pass-fulldeps/macro-crate-multi-decorator.rs
@@ -5,11 +5,9 @@
 // aux-build:macro_crate_test.rs
 // ignore-stage1
 
-#![feature(plugin, rustc_attrs)]
-#![plugin(macro_crate_test)]
+#![feature(rustc_attrs)]
 
 #[macro_use]
-#[no_link]
 extern crate macro_crate_test;
 
 // The duplicate macro will create a copy of the item with the given identifier.
diff --git a/src/test/run-pass-fulldeps/macro-crate.rs b/src/test/run-pass-fulldeps/macro-crate.rs
deleted file mode 100644
index 62838c2c0839d..0000000000000
--- a/src/test/run-pass-fulldeps/macro-crate.rs
+++ /dev/null
@@ -1,46 +0,0 @@
-#![allow(plugin_as_library)]
-#![allow(dead_code)]
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-
-#![feature(plugin, rustc_attrs)]
-#![plugin(macro_crate_test)]
-
-#[macro_use] #[no_link]
-extern crate macro_crate_test;
-
-#[rustc_into_multi_foo]
-#[derive(PartialEq, Clone, Debug)]
-fn foo() -> AnotherFakeTypeThatHadBetterGoAway {}
-
-// Check that the `#[into_multi_foo]`-generated `foo2` is configured away
-fn foo2() {}
-
-trait Qux {
-    #[rustc_into_multi_foo]
-    fn bar();
-}
-
-impl Qux for i32 {
-    #[rustc_into_multi_foo]
-    fn bar() {}
-}
-
-impl Qux for u8 {}
-
-pub fn main() {
-    assert_eq!(1, make_a_1!());
-    assert_eq!(2, exported_macro!());
-
-    assert_eq!(Foo2::Bar2, Foo2::Bar2);
-    test(None::<Foo2>);
-
-    let _ = Foo3::Bar;
-
-    let x = 10i32;
-    assert_eq!(x.foo(), 42);
-    let x = 10u8;
-    assert_eq!(x.foo(), 0);
-}
-
-fn test<T: PartialEq+Clone>(_: Option<T>) {}
diff --git a/src/test/run-pass-fulldeps/mbe_matching_test_macro.rs b/src/test/run-pass-fulldeps/mbe_matching_test_macro.rs
deleted file mode 100644
index c672081edf48c..0000000000000
--- a/src/test/run-pass-fulldeps/mbe_matching_test_macro.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-// aux-build:procedural_mbe_matching.rs
-// ignore-stage1
-
-#![feature(plugin)]
-#![plugin(procedural_mbe_matching)]
-
-pub fn main() {
-    assert_eq!(matches!(Some(123), None | Some(0)), false);
-    assert_eq!(matches!(Some(123), None | Some(123)), true);
-    assert_eq!(matches!(true, true), true);
-}
diff --git a/src/test/run-pass-fulldeps/plugin-lib-ok-in-plugin.rs b/src/test/run-pass-fulldeps/plugin-lib-ok-in-plugin.rs
deleted file mode 100644
index e9f234f7f545e..0000000000000
--- a/src/test/run-pass-fulldeps/plugin-lib-ok-in-plugin.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// aux-build:macro_crate_test.rs
-// aux-build:plugin_with_plugin_lib.rs
-// ignore-stage1
-// ignore-cross-compile
-//
-// macro_crate_test will not compile on a cross-compiled target because
-// libsyntax is not compiled for it.
-
-#![deny(plugin_as_library)]
-#![feature(plugin)]
-#![plugin(macro_crate_test)]
-#![plugin(plugin_with_plugin_lib)]
-
-fn main() {
-    assert_eq!(1, make_a_1!());
-}
diff --git a/src/test/run-pass-fulldeps/plugin-plus-extern-crate.rs b/src/test/run-pass-fulldeps/plugin-plus-extern-crate.rs
deleted file mode 100644
index e45a7f59c1bdc..0000000000000
--- a/src/test/run-pass-fulldeps/plugin-plus-extern-crate.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-// ignore-cross-compile
-//
-// macro_crate_test will not compile on a cross-compiled target because
-// libsyntax is not compiled for it.
-
-#![allow(plugin_as_library)]
-#![feature(plugin)]
-#![plugin(macro_crate_test)]
-
-extern crate macro_crate_test;
-
-fn main() {
-    assert_eq!(1, make_a_1!());
-    macro_crate_test::foo();
-}
diff --git a/src/test/run-pass-fulldeps/pprust-expr-roundtrip.rs b/src/test/run-pass-fulldeps/pprust-expr-roundtrip.rs
index ce3b03efd2604..956bc5ad862ca 100644
--- a/src/test/run-pass-fulldeps/pprust-expr-roundtrip.rs
+++ b/src/test/run-pass-fulldeps/pprust-expr-roundtrip.rs
@@ -27,7 +27,7 @@ use rustc_data_structures::thin_vec::ThinVec;
 use syntax::ast::*;
 use syntax::source_map::{Spanned, DUMMY_SP, FileName};
 use syntax::source_map::FilePathMapping;
-use syntax::fold::{self, Folder};
+use syntax::mut_visit::{self, MutVisitor, visit_clobber};
 use syntax::parse::{self, ParseSess};
 use syntax::print::pprust;
 use syntax::ptr::P;
@@ -59,8 +59,8 @@ fn make_x() -> P<Expr> {
     expr(ExprKind::Path(None, path))
 }
 
-/// Iterate over exprs of depth up to `depth`.  The goal is to explore all "interesting"
-/// combinations of expression nesting.  For example, we explore combinations using `if`, but not
+/// Iterate over exprs of depth up to `depth`. The goal is to explore all "interesting"
+/// combinations of expression nesting. For example, we explore combinations using `if`, but not
 /// `while` or `match`, since those should print and parse in much the same way as `if`.
 fn iter_exprs(depth: usize, f: &mut FnMut(P<Expr>)) {
     if depth == 0 {
@@ -157,32 +157,34 @@ fn iter_exprs(depth: usize, f: &mut FnMut(P<Expr>)) {
 
 // Folders for manipulating the placement of `Paren` nodes.  See below for why this is needed.
 
-/// Folder that removes all `ExprKind::Paren` nodes.
+/// MutVisitor that removes all `ExprKind::Paren` nodes.
 struct RemoveParens;
 
-impl Folder for RemoveParens {
-    fn fold_expr(&mut self, e: P<Expr>) -> P<Expr> {
-        let e = match e.node {
-            ExprKind::Paren(ref inner) => inner.clone(),
-            _ => e.clone(),
+impl MutVisitor for RemoveParens {
+    fn visit_expr(&mut self, e: &mut P<Expr>) {
+        match e.node.clone() {
+            ExprKind::Paren(inner) => *e = inner,
+            _ => {}
         };
-        e.map(|e| fold::noop_fold_expr(e, self))
+        mut_visit::noop_visit_expr(e, self);
     }
 }
 
 
-/// Folder that inserts `ExprKind::Paren` nodes around every `Expr`.
+/// MutVisitor that inserts `ExprKind::Paren` nodes around every `Expr`.
 struct AddParens;
 
-impl Folder for AddParens {
-    fn fold_expr(&mut self, e: P<Expr>) -> P<Expr> {
-        let e = e.map(|e| fold::noop_fold_expr(e, self));
-        P(Expr {
-            id: DUMMY_NODE_ID,
-            node: ExprKind::Paren(e),
-            span: DUMMY_SP,
-            attrs: ThinVec::new(),
-        })
+impl MutVisitor for AddParens {
+    fn visit_expr(&mut self, e: &mut P<Expr>) {
+        mut_visit::noop_visit_expr(e, self);
+        visit_clobber(e, |e| {
+            P(Expr {
+                id: DUMMY_NODE_ID,
+                node: ExprKind::Paren(e),
+                span: DUMMY_SP,
+                attrs: ThinVec::new(),
+            })
+        });
     }
 }
 
@@ -193,13 +195,13 @@ fn main() {
 fn run() {
     let ps = ParseSess::new(FilePathMapping::empty());
 
-    iter_exprs(2, &mut |e| {
+    iter_exprs(2, &mut |mut e| {
         // If the pretty printer is correct, then `parse(print(e))` should be identical to `e`,
         // modulo placement of `Paren` nodes.
         let printed = pprust::expr_to_string(&e);
         println!("printed: {}", printed);
 
-        let parsed = parse_expr(&ps, &printed);
+        let mut parsed = parse_expr(&ps, &printed);
 
         // We want to know if `parsed` is structurally identical to `e`, ignoring trivial
         // differences like placement of `Paren`s or the exact ranges of node spans.
@@ -207,10 +209,12 @@ fn run() {
         // everywhere we can, then pretty-print.  This should give an unambiguous representation of
         // each `Expr`, and it bypasses nearly all of the parenthesization logic, so we aren't
         // relying on the correctness of the very thing we're testing.
-        let e1 = AddParens.fold_expr(RemoveParens.fold_expr(e));
-        let text1 = pprust::expr_to_string(&e1);
-        let e2 = AddParens.fold_expr(RemoveParens.fold_expr(parsed));
-        let text2 = pprust::expr_to_string(&e2);
+        RemoveParens.visit_expr(&mut e);
+        AddParens.visit_expr(&mut e);
+        let text1 = pprust::expr_to_string(&e);
+        RemoveParens.visit_expr(&mut parsed);
+        AddParens.visit_expr(&mut parsed);
+        let text2 = pprust::expr_to_string(&parsed);
         assert!(text1 == text2,
                 "exprs are not equal:\n  e =      {:?}\n  parsed = {:?}",
                 text1, text2);
diff --git a/src/test/run-pass-fulldeps/qquote.rs b/src/test/run-pass-fulldeps/qquote.rs
deleted file mode 100644
index 33063fc74bfb3..0000000000000
--- a/src/test/run-pass-fulldeps/qquote.rs
+++ /dev/null
@@ -1,92 +0,0 @@
-#![allow(unused_imports)]
-// ignore-cross-compile
-
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_pos;
-
-use syntax::source_map::FilePathMapping;
-use syntax::print::pprust::*;
-use syntax::symbol::Symbol;
-use syntax_pos::DUMMY_SP;
-
-fn main() {
-    syntax::with_globals(|| run());
-}
-
-fn run() {
-    let ps = syntax::parse::ParseSess::new(FilePathMapping::empty());
-    let mut resolver = syntax::ext::base::DummyResolver;
-    let mut cx = syntax::ext::base::ExtCtxt::new(
-        &ps,
-        syntax::ext::expand::ExpansionConfig::default("qquote".to_string()),
-        &mut resolver);
-    let cx = &mut cx;
-
-    macro_rules! check {
-        ($f: ident, $($e: expr),+; $expect: expr) => ({
-            $(assert_eq!($f(&$e), $expect);)+
-        });
-    }
-
-    let abc = quote_expr!(cx, 23);
-    check!(expr_to_string, abc, *quote_expr!(cx, $abc); "23");
-
-    let ty = quote_ty!(cx, isize);
-    check!(ty_to_string, ty, *quote_ty!(cx, $ty); "isize");
-
-    let item = quote_item!(cx, static x: $ty = 10;).unwrap();
-    check!(item_to_string, item, quote_item!(cx, $item).unwrap(); "static x: isize = 10;");
-
-    let twenty: u16 = 20;
-    let stmt = quote_stmt!(cx, let x = $twenty;).unwrap();
-    check!(stmt_to_string, stmt, quote_stmt!(cx, $stmt).unwrap(); "let x = 20u16;");
-
-    let pat = quote_pat!(cx, Some(_));
-    check!(pat_to_string, pat, *quote_pat!(cx, $pat); "Some(_)");
-
-    let expr = quote_expr!(cx, (x, y));
-    let arm = quote_arm!(cx, (ref x, ref y) => $expr,);
-    check!(arm_to_string, arm, quote_arm!(cx, $arm); " (ref x, ref y) => (x, y),");
-
-    let attr = quote_attr!(cx, #![cfg(foo = "bar")]);
-    check!(attribute_to_string, attr, quote_attr!(cx, $attr); r#"#![cfg(foo = "bar")]"#);
-
-    // quote_arg!
-
-    let arg = quote_arg!(cx, foo: i32);
-    check!(arg_to_string, arg, quote_arg!(cx, $arg); "foo: i32");
-
-    let function = quote_item!(cx, fn f($arg) { }).unwrap();
-    check!(item_to_string, function; "fn f(foo: i32) { }");
-
-    let args = vec![arg, quote_arg!(cx, bar: u32)];
-    let args = &args[..];
-    let function = quote_item!(cx, fn f($args) { }).unwrap();
-    check!(item_to_string, function; "fn f(foo: i32, bar: u32) { }");
-
-    // quote_block!
-
-    let block = quote_block!(cx, { $stmt let y = 40u32; });
-    check!(block_to_string, block, *quote_block!(cx, $block); "{ let x = 20u16; let y = 40u32; }");
-
-    let function = quote_item!(cx, fn f() $block).unwrap();
-    check!(item_to_string, function; "fn f() { let x = 20u16; let y = 40u32; }");
-
-    // quote_path!
-
-    let path = quote_path!(cx, ::syntax::ptr::P<MetaItem>);
-    check!(path_to_string, path, quote_path!(cx, $path); "::syntax::ptr::P<MetaItem>");
-
-    let ty = quote_ty!(cx, $path);
-    check!(ty_to_string, ty; "::syntax::ptr::P<MetaItem>");
-
-    // quote_meta_item!
-
-    let meta = quote_meta_item!(cx, cfg(foo = "bar"));
-    check!(meta_item_to_string, meta, quote_meta_item!(cx, $meta); r#"cfg(foo = "bar")"#);
-
-    let attr = quote_attr!(cx, #![$meta]);
-    check!(attribute_to_string, attr; r#"#![cfg(foo = "bar")]"#);
-}
diff --git a/src/test/run-pass-fulldeps/quote-tokens.rs b/src/test/run-pass-fulldeps/quote-tokens.rs
deleted file mode 100644
index 04a4c442e0025..0000000000000
--- a/src/test/run-pass-fulldeps/quote-tokens.rs
+++ /dev/null
@@ -1,45 +0,0 @@
-#![allow(dead_code)]
-#![allow(unused_variables)]
-#![allow(unused_imports)]
-// ignore-cross-compile
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-
-use syntax::ext::base::ExtCtxt;
-use syntax::ptr::P;
-use syntax::parse::PResult;
-
-fn syntax_extension(cx: &ExtCtxt) {
-    let e_toks : Vec<syntax::tokenstream::TokenTree> = quote_tokens!(cx, 1 + 2);
-    let p_toks : Vec<syntax::tokenstream::TokenTree> = quote_tokens!(cx, (x, 1 .. 4, *));
-
-    let a: P<syntax::ast::Expr> = quote_expr!(cx, 1 + 2);
-    let _b: Option<P<syntax::ast::Item>> = quote_item!(cx, static foo : isize = $e_toks; );
-    let _c: P<syntax::ast::Pat> = quote_pat!(cx, (x, 1 .. 4, *) );
-    let _d: Option<syntax::ast::Stmt> = quote_stmt!(cx, let x = $a; );
-    let _d: syntax::ast::Arm = quote_arm!(cx, (ref x, ref y) = (x, y) );
-    let _e: P<syntax::ast::Expr> = quote_expr!(cx, match foo { $p_toks => 10 } );
-
-    let _f: P<syntax::ast::Expr> = quote_expr!(cx, ());
-    let _g: P<syntax::ast::Expr> = quote_expr!(cx, true);
-    let _h: P<syntax::ast::Expr> = quote_expr!(cx, 'a');
-
-    let i: Option<P<syntax::ast::Item>> = quote_item!(cx, #[derive(Eq)] struct Foo; );
-    assert!(i.is_some());
-
-    let _l: P<syntax::ast::Ty> = quote_ty!(cx, &isize);
-
-    let _n: syntax::ast::Attribute = quote_attr!(cx, #![cfg(foo, bar = "baz")]);
-
-    let _o: Option<P<syntax::ast::Item>> = quote_item!(cx, fn foo<T: ?Sized>() {});
-
-    let stmts = vec![
-        quote_stmt!(cx, let x = 1;).unwrap(),
-        quote_stmt!(cx, let y = 2;).unwrap(),
-    ];
-    let expr: P<syntax::ast::Expr> = quote_expr!(cx, x + y);
-}
-
-fn main() {
-}
diff --git a/src/test/run-pass-fulldeps/quote-unused-sp-no-warning.rs b/src/test/run-pass-fulldeps/quote-unused-sp-no-warning.rs
deleted file mode 100644
index 1568bf2603986..0000000000000
--- a/src/test/run-pass-fulldeps/quote-unused-sp-no-warning.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-#![allow(dead_code)]
-// ignore-cross-compile
-#![feature(quote, rustc_private)]
-#![deny(unused_variables)]
-
-extern crate syntax;
-
-use syntax::ext::base::ExtCtxt;
-
-fn test(cx: &mut ExtCtxt) {
-    let foo = 10;
-    let _e = quote_expr!(cx, $foo);
-}
-
-pub fn main() { }
diff --git a/src/test/run-pass-fulldeps/syntax-extension-with-dll-deps.rs b/src/test/run-pass-fulldeps/syntax-extension-with-dll-deps.rs
deleted file mode 100644
index 7c236fd69eae6..0000000000000
--- a/src/test/run-pass-fulldeps/syntax-extension-with-dll-deps.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// aux-build:syntax_extension_with_dll_deps_1.rs
-// aux-build:syntax_extension_with_dll_deps_2.rs
-// ignore-stage1
-
-#![feature(plugin, rustc_private)]
-#![plugin(syntax_extension_with_dll_deps_2)]
-
-fn main() {
-    foo!();
-}
diff --git a/src/test/run-pass/allocator/auxiliary/custom-as-global.rs b/src/test/run-pass/allocator/auxiliary/custom-as-global.rs
index 6842e2c33b217..a5e96e7750184 100644
--- a/src/test/run-pass/allocator/auxiliary/custom-as-global.rs
+++ b/src/test/run-pass/allocator/auxiliary/custom-as-global.rs
@@ -4,12 +4,12 @@
 
 extern crate custom;
 
-use std::sync::atomic::{ATOMIC_USIZE_INIT, Ordering};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
 use custom::A;
 
 #[global_allocator]
-static ALLOCATOR: A = A(ATOMIC_USIZE_INIT);
+static ALLOCATOR: A = A(AtomicUsize::new(0));
 
 pub fn get() -> usize {
     ALLOCATOR.0.load(Ordering::SeqCst)
diff --git a/src/test/run-pass/allocator/custom.rs b/src/test/run-pass/allocator/custom.rs
index a8c6e0325e126..71f72ae46c23f 100644
--- a/src/test/run-pass/allocator/custom.rs
+++ b/src/test/run-pass/allocator/custom.rs
@@ -8,9 +8,9 @@
 extern crate helper;
 
 use std::alloc::{self, Global, Alloc, System, Layout};
-use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static HITS: AtomicUsize = ATOMIC_USIZE_INIT;
+static HITS: AtomicUsize = AtomicUsize::new(0);
 
 struct A;
 
diff --git a/src/test/run-pass/allocator/xcrate-use.rs b/src/test/run-pass/allocator/xcrate-use.rs
index eb911a62e91cb..039c70e77bedf 100644
--- a/src/test/run-pass/allocator/xcrate-use.rs
+++ b/src/test/run-pass/allocator/xcrate-use.rs
@@ -10,10 +10,10 @@ extern crate custom;
 extern crate helper;
 
 use std::alloc::{Global, Alloc, System, Layout};
-use std::sync::atomic::{Ordering, ATOMIC_USIZE_INIT};
+use std::sync::atomic::{Ordering, AtomicUsize};
 
 #[global_allocator]
-static GLOBAL: custom::A = custom::A(ATOMIC_USIZE_INIT);
+static GLOBAL: custom::A = custom::A(AtomicUsize::new(0));
 
 fn main() {
     unsafe {
diff --git a/src/test/run-pass/allocator/xcrate-use2.rs b/src/test/run-pass/allocator/xcrate-use2.rs
index be657f127bbc2..d8478fb5eaa41 100644
--- a/src/test/run-pass/allocator/xcrate-use2.rs
+++ b/src/test/run-pass/allocator/xcrate-use2.rs
@@ -12,9 +12,9 @@ extern crate custom_as_global;
 extern crate helper;
 
 use std::alloc::{alloc, dealloc, GlobalAlloc, System, Layout};
-use std::sync::atomic::{Ordering, ATOMIC_USIZE_INIT};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static GLOBAL: custom::A = custom::A(ATOMIC_USIZE_INIT);
+static GLOBAL: custom::A = custom::A(AtomicUsize::new(0));
 
 fn main() {
     unsafe {
@@ -45,4 +45,3 @@ fn main() {
         assert_eq!(GLOBAL.0.load(Ordering::SeqCst), 2);
     }
 }
-
diff --git a/src/test/run-pass/async-await.rs b/src/test/run-pass/async-await.rs
index 552f38215738b..1843feed927a2 100644
--- a/src/test/run-pass/async-await.rs
+++ b/src/test/run-pass/async-await.rs
@@ -1,7 +1,10 @@
 // edition:2018
+// aux-build:arc_wake.rs
 
 #![feature(arbitrary_self_types, async_await, await_macro, futures_api)]
 
+extern crate arc_wake;
+
 use std::pin::Pin;
 use std::future::Future;
 use std::sync::{
@@ -9,17 +12,17 @@ use std::sync::{
     atomic::{self, AtomicUsize},
 };
 use std::task::{
-    LocalWaker, Poll, Wake,
-    local_waker_from_nonlocal,
+    Poll, Waker,
 };
+use arc_wake::ArcWake;
 
 struct Counter {
     wakes: AtomicUsize,
 }
 
-impl Wake for Counter {
-    fn wake(this: &Arc<Self>) {
-        this.wakes.fetch_add(1, atomic::Ordering::SeqCst);
+impl ArcWake for Counter {
+    fn wake(arc_self: &Arc<Self>) {
+        arc_self.wakes.fetch_add(1, atomic::Ordering::SeqCst);
     }
 }
 
@@ -29,11 +32,11 @@ fn wake_and_yield_once() -> WakeOnceThenComplete { WakeOnceThenComplete(false) }
 
 impl Future for WakeOnceThenComplete {
     type Output = ();
-    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<()> {
+    fn poll(mut self: Pin<&mut Self>, waker: &Waker) -> Poll<()> {
         if self.0 {
             Poll::Ready(())
         } else {
-            lw.wake();
+            waker.wake();
             self.0 = true;
             Poll::Pending
         }
@@ -130,7 +133,7 @@ where
 {
     let mut fut = Box::pin(f(9));
     let counter = Arc::new(Counter { wakes: AtomicUsize::new(0) });
-    let waker = local_waker_from_nonlocal(counter.clone());
+    let waker = ArcWake::into_waker(counter.clone());
     assert_eq!(0, counter.wakes.load(atomic::Ordering::SeqCst));
     assert_eq!(Poll::Pending, fut.as_mut().poll(&waker));
     assert_eq!(1, counter.wakes.load(atomic::Ordering::SeqCst));
diff --git a/src/test/run-pass/atomic-access-bool.rs b/src/test/run-pass/atomic-access-bool.rs
index 4f804bcdef235..8522493232f98 100644
--- a/src/test/run-pass/atomic-access-bool.rs
+++ b/src/test/run-pass/atomic-access-bool.rs
@@ -1,9 +1,9 @@
 #![allow(stable_features)]
 #![feature(atomic_access)]
-use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT};
+use std::sync::atomic::AtomicBool;
 use std::sync::atomic::Ordering::*;
 
-static mut ATOMIC: AtomicBool = ATOMIC_BOOL_INIT;
+static mut ATOMIC: AtomicBool = AtomicBool::new(false);
 
 fn main() {
     unsafe {
diff --git a/src/test/run-pass/atomic-compare_exchange.rs b/src/test/run-pass/atomic-compare_exchange.rs
index c7b80c42c1baa..77da820e07c56 100644
--- a/src/test/run-pass/atomic-compare_exchange.rs
+++ b/src/test/run-pass/atomic-compare_exchange.rs
@@ -1,10 +1,10 @@
 #![allow(stable_features)]
 
 #![feature(extended_compare_and_swap)]
-use std::sync::atomic::{AtomicIsize, ATOMIC_ISIZE_INIT};
+use std::sync::atomic::AtomicIsize;
 use std::sync::atomic::Ordering::*;
 
-static ATOMIC: AtomicIsize = ATOMIC_ISIZE_INIT;
+static ATOMIC: AtomicIsize = AtomicIsize::new(0);
 
 fn main() {
     // Make sure codegen can emit all the intrinsics correctly
diff --git a/src/test/run-pass/auxiliary/arc_wake.rs b/src/test/run-pass/auxiliary/arc_wake.rs
new file mode 100644
index 0000000000000..034e378af7f19
--- /dev/null
+++ b/src/test/run-pass/auxiliary/arc_wake.rs
@@ -0,0 +1,56 @@
+// edition:2018
+
+#![feature(arbitrary_self_types, futures_api)]
+
+use std::sync::Arc;
+use std::task::{
+    Poll, Waker, RawWaker, RawWakerVTable,
+};
+
+macro_rules! waker_vtable {
+    ($ty:ident) => {
+        &RawWakerVTable {
+            clone: clone_arc_raw::<$ty>,
+            drop: drop_arc_raw::<$ty>,
+            wake: wake_arc_raw::<$ty>,
+        }
+    };
+}
+
+pub trait ArcWake {
+    fn wake(arc_self: &Arc<Self>);
+
+    fn into_waker(wake: Arc<Self>) -> Waker where Self: Sized
+    {
+        let ptr = Arc::into_raw(wake) as *const();
+
+        unsafe {
+            Waker::new_unchecked(RawWaker::new(ptr, waker_vtable!(Self)))
+        }
+    }
+}
+
+unsafe fn increase_refcount<T: ArcWake>(data: *const()) {
+    // Retain Arc by creating a copy
+    let arc: Arc<T> = Arc::from_raw(data as *const T);
+    let arc_clone = arc.clone();
+    // Forget the Arcs again, so that the refcount isn't decrased
+    let _ = Arc::into_raw(arc);
+    let _ = Arc::into_raw(arc_clone);
+}
+
+unsafe fn clone_arc_raw<T: ArcWake>(data: *const()) -> RawWaker {
+    increase_refcount::<T>(data);
+    RawWaker::new(data, waker_vtable!(T))
+}
+
+unsafe fn drop_arc_raw<T: ArcWake>(data: *const()) {
+    // Drop Arc
+    let _: Arc<T> = Arc::from_raw(data as *const T);
+}
+
+unsafe fn wake_arc_raw<T: ArcWake>(data: *const()) {
+    let arc: Arc<T> = Arc::from_raw(data as *const T);
+    ArcWake::wake(&arc);
+    let _ = Arc::into_raw(arc);
+}
diff --git a/src/test/run-pass/auxiliary/svh-b.rs b/src/test/run-pass/auxiliary/svh-b.rs
index 03869aeb37194..57029f70888b3 100644
--- a/src/test/run-pass/auxiliary/svh-b.rs
+++ b/src/test/run-pass/auxiliary/svh-b.rs
@@ -1,7 +1,7 @@
-//! This is a client of the `a` crate defined in "svn-a-base.rs".  The
-//! rpass and cfail tests (such as "run-pass/svh-add-comment.rs") use
+//! This is a client of the `a` crate defined in `svn-a-base.rs`. The
+//! rpass and cfail tests (such as `run-pass/svh-add-comment.rs`) use
 //! it by swapping in a different object code library crate built from
-//! some variant of "svn-a-base.rs", and then we are checking if the
+//! some variant of `svn-a-base.rs`, and then we are checking if the
 //! compiler properly ignores or accepts the change, based on whether
 //! the change could affect the downstream crate content or not
 //! (#14132).
diff --git a/src/test/run-pass/command-before-exec.rs b/src/test/run-pass/command-before-exec.rs
deleted file mode 100644
index 91d2636b2ae63..0000000000000
--- a/src/test/run-pass/command-before-exec.rs
+++ /dev/null
@@ -1,83 +0,0 @@
-#![allow(stable_features)]
-// ignore-windows - this is a unix-specific test
-// ignore-cloudabi no processes
-// ignore-emscripten no processes
-
-#![feature(process_exec, rustc_private)]
-
-extern crate libc;
-
-use std::env;
-use std::io::Error;
-use std::os::unix::process::CommandExt;
-use std::process::Command;
-use std::sync::Arc;
-use std::sync::atomic::{AtomicUsize, Ordering};
-
-fn main() {
-    if let Some(arg) = env::args().nth(1) {
-        match &arg[..] {
-            "test1" => println!("hello2"),
-            "test2" => assert_eq!(env::var("FOO").unwrap(), "BAR"),
-            "test3" => assert_eq!(env::current_dir().unwrap()
-                                      .to_str().unwrap(), "/"),
-            "empty" => {}
-            _ => panic!("unknown argument: {}", arg),
-        }
-        return
-    }
-
-    let me = env::current_exe().unwrap();
-
-    let output = Command::new(&me).arg("test1").before_exec(|| {
-        println!("hello");
-        Ok(())
-    }).output().unwrap();
-    assert!(output.status.success());
-    assert!(output.stderr.is_empty());
-    assert_eq!(output.stdout, b"hello\nhello2\n");
-
-    let output = Command::new(&me).arg("test2").before_exec(|| {
-        env::set_var("FOO", "BAR");
-        Ok(())
-    }).output().unwrap();
-    assert!(output.status.success());
-    assert!(output.stderr.is_empty());
-    assert!(output.stdout.is_empty());
-
-    let output = Command::new(&me).arg("test3").before_exec(|| {
-        env::set_current_dir("/").unwrap();
-        Ok(())
-    }).output().unwrap();
-    assert!(output.status.success());
-    assert!(output.stderr.is_empty());
-    assert!(output.stdout.is_empty());
-
-    let output = Command::new(&me).arg("bad").before_exec(|| {
-        Err(Error::from_raw_os_error(102))
-    }).output().unwrap_err();
-    assert_eq!(output.raw_os_error(), Some(102));
-
-    let pid = unsafe { libc::getpid() };
-    assert!(pid >= 0);
-    let output = Command::new(&me).arg("empty").before_exec(move || {
-        let child = unsafe { libc::getpid() };
-        assert!(child >= 0);
-        assert!(pid != child);
-        Ok(())
-    }).output().unwrap();
-    assert!(output.status.success());
-    assert!(output.stderr.is_empty());
-    assert!(output.stdout.is_empty());
-
-    let mem = Arc::new(AtomicUsize::new(0));
-    let mem2 = mem.clone();
-    let output = Command::new(&me).arg("empty").before_exec(move || {
-        assert_eq!(mem2.fetch_add(1, Ordering::SeqCst), 0);
-        Ok(())
-    }).output().unwrap();
-    assert!(output.status.success());
-    assert!(output.stderr.is_empty());
-    assert!(output.stdout.is_empty());
-    assert_eq!(mem.load(Ordering::SeqCst), 0);
-}
diff --git a/src/test/run-pass/command-pre-exec.rs b/src/test/run-pass/command-pre-exec.rs
new file mode 100644
index 0000000000000..21783fedd39c9
--- /dev/null
+++ b/src/test/run-pass/command-pre-exec.rs
@@ -0,0 +1,115 @@
+#![allow(stable_features)]
+// ignore-windows - this is a unix-specific test
+// ignore-cloudabi no processes
+// ignore-emscripten no processes
+#![feature(process_exec, rustc_private)]
+
+extern crate libc;
+
+use std::env;
+use std::io::Error;
+use std::os::unix::process::CommandExt;
+use std::process::Command;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+
+fn main() {
+    if let Some(arg) = env::args().nth(1) {
+        match &arg[..] {
+            "test1" => println!("hello2"),
+            "test2" => assert_eq!(env::var("FOO").unwrap(), "BAR"),
+            "test3" => assert_eq!(env::current_dir().unwrap().to_str().unwrap(), "/"),
+            "empty" => {}
+            _ => panic!("unknown argument: {}", arg),
+        }
+        return;
+    }
+
+    let me = env::current_exe().unwrap();
+
+    let output = unsafe {
+        Command::new(&me)
+            .arg("test1")
+            .pre_exec(|| {
+                println!("hello");
+                Ok(())
+            })
+            .output()
+            .unwrap()
+    };
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert_eq!(output.stdout, b"hello\nhello2\n");
+
+    let output = unsafe {
+        Command::new(&me)
+            .arg("test2")
+            .pre_exec(|| {
+                env::set_var("FOO", "BAR");
+                Ok(())
+            })
+            .output()
+            .unwrap()
+    };
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert!(output.stdout.is_empty());
+
+    let output = unsafe {
+        Command::new(&me)
+            .arg("test3")
+            .pre_exec(|| {
+                env::set_current_dir("/").unwrap();
+                Ok(())
+            })
+            .output()
+            .unwrap()
+    };
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert!(output.stdout.is_empty());
+
+    let output = unsafe {
+        Command::new(&me)
+            .arg("bad")
+            .pre_exec(|| Err(Error::from_raw_os_error(102)))
+            .output()
+            .unwrap_err()
+    };
+    assert_eq!(output.raw_os_error(), Some(102));
+
+    let pid = unsafe { libc::getpid() };
+    assert!(pid >= 0);
+    let output = unsafe {
+        Command::new(&me)
+            .arg("empty")
+            .pre_exec(move || {
+                let child = libc::getpid();
+                assert!(child >= 0);
+                assert!(pid != child);
+                Ok(())
+            })
+            .output()
+            .unwrap()
+    };
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert!(output.stdout.is_empty());
+
+    let mem = Arc::new(AtomicUsize::new(0));
+    let mem2 = mem.clone();
+    let output = unsafe {
+        Command::new(&me)
+            .arg("empty")
+            .pre_exec(move || {
+                assert_eq!(mem2.fetch_add(1, Ordering::SeqCst), 0);
+                Ok(())
+            })
+            .output()
+            .unwrap()
+    };
+    assert!(output.status.success());
+    assert!(output.stderr.is_empty());
+    assert!(output.stdout.is_empty());
+    assert_eq!(mem.load(Ordering::SeqCst), 0);
+}
diff --git a/src/test/run-pass/const-int-overflowing.rs b/src/test/run-pass/const-int-overflowing.rs
index 289b1236cf1e2..82057868b73bb 100644
--- a/src/test/run-pass/const-int-overflowing.rs
+++ b/src/test/run-pass/const-int-overflowing.rs
@@ -13,6 +13,9 @@ const SHL_B: (u32, bool) = 0x1u32.overflowing_shl(132);
 const SHR_A: (u32, bool) = 0x10u32.overflowing_shr(4);
 const SHR_B: (u32, bool) = 0x10u32.overflowing_shr(132);
 
+const NEG_A: (u32, bool) = 0u32.overflowing_neg();
+const NEG_B: (u32, bool) = core::u32::MAX.overflowing_neg();
+
 fn ident<T>(ident: T) -> T {
     ident
 }
@@ -32,4 +35,7 @@ fn main() {
 
     assert_eq!(SHR_A, ident((0x1, false)));
     assert_eq!(SHR_B, ident((0x1, true)));
+
+    assert_eq!(NEG_A, ident((0, false)));
+    assert_eq!(NEG_B, ident((1, true)));
 }
diff --git a/src/test/run-pass/const-int-saturating-arith.rs b/src/test/run-pass/const-int-saturating-arith.rs
new file mode 100644
index 0000000000000..dae4c7216b2c0
--- /dev/null
+++ b/src/test/run-pass/const-int-saturating-arith.rs
@@ -0,0 +1,34 @@
+// ignore-emscripten no i128 support
+#![feature(const_saturating_int_methods)]
+
+const INT_U32_NO: u32 = (42 as u32).saturating_add(2);
+const INT_U32: u32 = u32::max_value().saturating_add(1);
+const INT_U128: u128 = u128::max_value().saturating_add(1);
+const INT_I128: i128 = i128::max_value().saturating_add(1);
+const INT_I128_NEG: i128 = i128::min_value().saturating_add(-1);
+
+const INT_U32_NO_SUB: u32 = (42 as u32).saturating_sub(2);
+const INT_U32_SUB: u32 = (1 as u32).saturating_sub(2);
+const INT_I32_NO_SUB: i32 = (-42 as i32).saturating_sub(2);
+const INT_I32_NEG_SUB: i32 = i32::min_value().saturating_sub(1);
+const INT_I32_POS_SUB: i32 = i32::max_value().saturating_sub(-1);
+const INT_U128_SUB: u128 = (0 as u128).saturating_sub(1);
+const INT_I128_NEG_SUB: i128 = i128::min_value().saturating_sub(1);
+const INT_I128_POS_SUB: i128 = i128::max_value().saturating_sub(-1);
+
+fn main() {
+    assert_eq!(INT_U32_NO, 44);
+    assert_eq!(INT_U32, u32::max_value());
+    assert_eq!(INT_U128, u128::max_value());
+    assert_eq!(INT_I128, i128::max_value());
+    assert_eq!(INT_I128_NEG, i128::min_value());
+
+    assert_eq!(INT_U32_NO_SUB, 40);
+    assert_eq!(INT_U32_SUB, 0);
+    assert_eq!(INT_I32_NO_SUB, -44);
+    assert_eq!(INT_I32_NEG_SUB, i32::min_value());
+    assert_eq!(INT_I32_POS_SUB, i32::max_value());
+    assert_eq!(INT_U128_SUB, 0);
+    assert_eq!(INT_I128_NEG_SUB, i128::min_value());
+    assert_eq!(INT_I128_POS_SUB, i128::max_value());
+}
diff --git a/src/test/run-pass/const-int-wrapping.rs b/src/test/run-pass/const-int-wrapping.rs
index 5ab712015dfc3..140fd57ecb802 100644
--- a/src/test/run-pass/const-int-wrapping.rs
+++ b/src/test/run-pass/const-int-wrapping.rs
@@ -13,6 +13,9 @@ const SHL_B: u32 = 1u32.wrapping_shl(128);
 const SHR_A: u32 = 128u32.wrapping_shr(7);
 const SHR_B: u32 = 128u32.wrapping_shr(128);
 
+const NEG_A: u32 = 5u32.wrapping_neg();
+const NEG_B: u32 = 1234567890u32.wrapping_neg();
+
 fn ident<T>(ident: T) -> T {
     ident
 }
@@ -32,4 +35,7 @@ fn main() {
 
     assert_eq!(SHR_A, ident(1));
     assert_eq!(SHR_B, ident(128));
+
+    assert_eq!(NEG_A, ident(4294967291));
+    assert_eq!(NEG_B, ident(3060399406));
 }
diff --git a/src/test/run-pass/deriving/deriving-copyclone.rs b/src/test/run-pass/deriving/deriving-copyclone.rs
index cdeb5d03d35c6..78d74a11ffc8b 100644
--- a/src/test/run-pass/deriving/deriving-copyclone.rs
+++ b/src/test/run-pass/deriving/deriving-copyclone.rs
@@ -2,7 +2,7 @@
 //! Test that #[derive(Copy, Clone)] produces a shallow copy
 //! even when a member violates RFC 1521
 
-use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
+use std::sync::atomic::{AtomicBool, Ordering};
 
 /// A struct that pretends to be Copy, but actually does something
 /// in its Clone impl
@@ -10,7 +10,7 @@ use std::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
 struct Liar;
 
 /// Static cooperating with the rogue Clone impl
-static CLONED: AtomicBool = ATOMIC_BOOL_INIT;
+static CLONED: AtomicBool = AtomicBool::new(false);
 
 impl Clone for Liar {
     fn clone(&self) -> Self {
@@ -36,4 +36,3 @@ fn main() {
     // if Innocent was byte-for-byte copied, CLONED will still be false
     assert!(!CLONED.load(Ordering::SeqCst));
 }
-
diff --git a/src/test/run-pass/drop/dynamic-drop.rs b/src/test/run-pass/drop/dynamic-drop.rs
index 41814f2af16b4..97e4cded80b9a 100644
--- a/src/test/run-pass/drop/dynamic-drop.rs
+++ b/src/test/run-pass/drop/dynamic-drop.rs
@@ -12,6 +12,7 @@
 use std::cell::{Cell, RefCell};
 use std::ops::Generator;
 use std::panic;
+use std::pin::Pin;
 use std::usize;
 
 struct InjectedFailure;
@@ -172,7 +173,7 @@ fn generator(a: &Allocator, run_count: usize) {
          );
     };
     for _ in 0..run_count {
-        unsafe { gen.resume(); }
+        Pin::new(&mut gen).resume();
     }
 }
 
diff --git a/src/test/run-pass/futures-api.rs b/src/test/run-pass/futures-api.rs
index e3023521100c4..fd4b585d34572 100644
--- a/src/test/run-pass/futures-api.rs
+++ b/src/test/run-pass/futures-api.rs
@@ -1,30 +1,28 @@
+// aux-build:arc_wake.rs
+
 #![feature(arbitrary_self_types, futures_api)]
 #![allow(unused)]
 
+extern crate arc_wake;
+
 use std::future::Future;
 use std::pin::Pin;
-use std::rc::Rc;
 use std::sync::{
     Arc,
     atomic::{self, AtomicUsize},
 };
 use std::task::{
-    Poll, Wake, Waker, LocalWaker,
-    local_waker, local_waker_from_nonlocal,
+    Poll, Waker,
 };
+use arc_wake::ArcWake;
 
 struct Counter {
-    local_wakes: AtomicUsize,
-    nonlocal_wakes: AtomicUsize,
+    wakes: AtomicUsize,
 }
 
-impl Wake for Counter {
-    fn wake(this: &Arc<Self>) {
-        this.nonlocal_wakes.fetch_add(1, atomic::Ordering::SeqCst);
-    }
-
-    unsafe fn wake_local(this: &Arc<Self>) {
-        this.local_wakes.fetch_add(1, atomic::Ordering::SeqCst);
+impl ArcWake for Counter {
+    fn wake(arc_self: &Arc<Self>) {
+        arc_self.wakes.fetch_add(1, atomic::Ordering::SeqCst);
     }
 }
 
@@ -32,40 +30,28 @@ struct MyFuture;
 
 impl Future for MyFuture {
     type Output = ();
-    fn poll(self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
-        // Wake once locally
-        lw.wake();
-        // Wake twice non-locally
-        let waker = lw.clone().into_waker();
+    fn poll(self: Pin<&mut Self>, waker: &Waker) -> Poll<Self::Output> {
+        // Wake twice
         waker.wake();
         waker.wake();
         Poll::Ready(())
     }
 }
 
-fn test_local_waker() {
+fn test_waker() {
     let counter = Arc::new(Counter {
-        local_wakes: AtomicUsize::new(0),
-        nonlocal_wakes: AtomicUsize::new(0),
+        wakes: AtomicUsize::new(0),
     });
-    let waker = unsafe { local_waker(counter.clone()) };
-    assert_eq!(Poll::Ready(()), Pin::new(&mut MyFuture).poll(&waker));
-    assert_eq!(1, counter.local_wakes.load(atomic::Ordering::SeqCst));
-    assert_eq!(2, counter.nonlocal_wakes.load(atomic::Ordering::SeqCst));
-}
+    let waker = ArcWake::into_waker(counter.clone());
+    assert_eq!(2, Arc::strong_count(&counter));
 
-fn test_local_as_nonlocal_waker() {
-    let counter = Arc::new(Counter {
-        local_wakes: AtomicUsize::new(0),
-        nonlocal_wakes: AtomicUsize::new(0),
-    });
-    let waker: LocalWaker = local_waker_from_nonlocal(counter.clone());
     assert_eq!(Poll::Ready(()), Pin::new(&mut MyFuture).poll(&waker));
-    assert_eq!(0, counter.local_wakes.load(atomic::Ordering::SeqCst));
-    assert_eq!(3, counter.nonlocal_wakes.load(atomic::Ordering::SeqCst));
+    assert_eq!(2, counter.wakes.load(atomic::Ordering::SeqCst));
+
+    drop(waker);
+    assert_eq!(1, Arc::strong_count(&counter));
 }
 
 fn main() {
-    test_local_waker();
-    test_local_as_nonlocal_waker();
+    test_waker();
 }
diff --git a/src/test/run-pass/generator/auxiliary/xcrate.rs b/src/test/run-pass/generator/auxiliary/xcrate.rs
index 8e08de28bc6b2..613c495832f00 100644
--- a/src/test/run-pass/generator/auxiliary/xcrate.rs
+++ b/src/test/run-pass/generator/auxiliary/xcrate.rs
@@ -1,5 +1,6 @@
 #![feature(generators, generator_trait)]
 
+use std::marker::Unpin;
 use std::ops::Generator;
 
 pub fn foo() -> impl Generator<Yield = (), Return = ()> {
@@ -10,7 +11,7 @@ pub fn foo() -> impl Generator<Yield = (), Return = ()> {
     }
 }
 
-pub fn bar<T: 'static>(t: T) -> Box<Generator<Yield = T, Return = ()>> {
+pub fn bar<T: 'static>(t: T) -> Box<Generator<Yield = T, Return = ()> + Unpin> {
     Box::new(|| {
         yield t;
     })
diff --git a/src/test/run-pass/generator/conditional-drop.rs b/src/test/run-pass/generator/conditional-drop.rs
index b7d7681d25c9e..907f7a3c06de7 100644
--- a/src/test/run-pass/generator/conditional-drop.rs
+++ b/src/test/run-pass/generator/conditional-drop.rs
@@ -3,9 +3,10 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::pin::Pin;
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static A: AtomicUsize = ATOMIC_USIZE_INIT;
+static A: AtomicUsize = AtomicUsize::new(0);
 
 struct B;
 
@@ -34,9 +35,9 @@ fn t1() {
     };
 
     let n = A.load(Ordering::SeqCst);
-    unsafe { a.resume() };
+    Pin::new(&mut a).resume();
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
-    unsafe { a.resume() };
+    Pin::new(&mut a).resume();
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
 }
 
@@ -50,8 +51,8 @@ fn t2() {
     };
 
     let n = A.load(Ordering::SeqCst);
-    unsafe { a.resume() };
+    Pin::new(&mut a).resume();
     assert_eq!(A.load(Ordering::SeqCst), n);
-    unsafe { a.resume() };
+    Pin::new(&mut a).resume();
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
 }
diff --git a/src/test/run-pass/generator/control-flow.rs b/src/test/run-pass/generator/control-flow.rs
index 2f499834796cc..df70e013bd330 100644
--- a/src/test/run-pass/generator/control-flow.rs
+++ b/src/test/run-pass/generator/control-flow.rs
@@ -2,13 +2,15 @@
 
 #![feature(generators, generator_trait)]
 
+use std::marker::Unpin;
 use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
 
 fn finish<T>(mut amt: usize, mut t: T) -> T::Return
-    where T: Generator<Yield = ()>
+    where T: Generator<Yield = ()> + Unpin,
 {
     loop {
-        match unsafe { t.resume() } {
+        match Pin::new(&mut t).resume() {
             GeneratorState::Yielded(()) => amt = amt.checked_sub(1).unwrap(),
             GeneratorState::Complete(ret) => {
                 assert_eq!(amt, 0);
diff --git a/src/test/run-pass/generator/drop-env.rs b/src/test/run-pass/generator/drop-env.rs
index bd988897710f7..ac4e06656285e 100644
--- a/src/test/run-pass/generator/drop-env.rs
+++ b/src/test/run-pass/generator/drop-env.rs
@@ -3,9 +3,10 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::pin::Pin;
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static A: AtomicUsize = ATOMIC_USIZE_INIT;
+static A: AtomicUsize = AtomicUsize::new(0);
 
 struct B;
 
@@ -29,7 +30,7 @@ fn t1() {
     };
 
     let n = A.load(Ordering::SeqCst);
-    drop(unsafe { foo.resume() });
+    drop(Pin::new(&mut foo).resume());
     assert_eq!(A.load(Ordering::SeqCst), n);
     drop(foo);
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
@@ -42,7 +43,7 @@ fn t2() {
     };
 
     let n = A.load(Ordering::SeqCst);
-    drop(unsafe { foo.resume() });
+    drop(Pin::new(&mut foo).resume());
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
     drop(foo);
     assert_eq!(A.load(Ordering::SeqCst), n + 1);
diff --git a/src/test/run-pass/generator/issue-44197.rs b/src/test/run-pass/generator/issue-44197.rs
index 4a6e5b88b235a..6efaff50c1e62 100644
--- a/src/test/run-pass/generator/issue-44197.rs
+++ b/src/test/run-pass/generator/issue-44197.rs
@@ -3,6 +3,7 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::{ Generator, GeneratorState };
+use std::pin::Pin;
 
 fn foo(_: &str) -> String {
     String::new()
@@ -27,8 +28,6 @@ fn bar2(baz: String) -> impl Generator<Yield = String, Return = ()> {
 }
 
 fn main() {
-    unsafe {
-        assert_eq!(bar(String::new()).resume(), GeneratorState::Yielded(String::new()));
-        assert_eq!(bar2(String::new()).resume(), GeneratorState::Complete(()));
-    }
+    assert_eq!(Pin::new(&mut bar(String::new())).resume(), GeneratorState::Yielded(String::new()));
+    assert_eq!(Pin::new(&mut bar2(String::new())).resume(), GeneratorState::Complete(()));
 }
diff --git a/src/test/run-pass/generator/iterator-count.rs b/src/test/run-pass/generator/iterator-count.rs
index 1011d54bdb33c..ac7e122dd5802 100644
--- a/src/test/run-pass/generator/iterator-count.rs
+++ b/src/test/run-pass/generator/iterator-count.rs
@@ -2,24 +2,26 @@
 
 #![feature(generators, generator_trait)]
 
+use std::marker::Unpin;
 use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
 
 struct W<T>(T);
 
 // This impl isn't safe in general, but the generator used in this test is movable
 // so it won't cause problems.
-impl<T: Generator<Return = ()>> Iterator for W<T> {
+impl<T: Generator<Return = ()> + Unpin> Iterator for W<T> {
     type Item = T::Yield;
 
     fn next(&mut self) -> Option<Self::Item> {
-        match unsafe { self.0.resume() } {
+        match Pin::new(&mut self.0).resume() {
             GeneratorState::Complete(..) => None,
             GeneratorState::Yielded(v) => Some(v),
         }
     }
 }
 
-fn test() -> impl Generator<Return=(), Yield=u8> {
+fn test() -> impl Generator<Return=(), Yield=u8> + Unpin {
     || {
         for i in 1..6 {
             yield i
diff --git a/src/test/run-pass/generator/live-upvar-across-yield.rs b/src/test/run-pass/generator/live-upvar-across-yield.rs
index b643809e50382..a1064165b2f7a 100644
--- a/src/test/run-pass/generator/live-upvar-across-yield.rs
+++ b/src/test/run-pass/generator/live-upvar-across-yield.rs
@@ -3,11 +3,12 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
     let b = |_| 3;
     let mut a = || {
         b(yield);
     };
-    unsafe { a.resume() };
+    Pin::new(&mut a).resume();
 }
diff --git a/src/test/run-pass/generator/nested_generators.rs b/src/test/run-pass/generator/nested_generators.rs
index e837e5fc9c1fe..b56cce1dc44f1 100644
--- a/src/test/run-pass/generator/nested_generators.rs
+++ b/src/test/run-pass/generator/nested_generators.rs
@@ -1,10 +1,9 @@
 // run-pass
 
-#![feature(generators)]
-#![feature(generator_trait)]
+#![feature(generators, generator_trait)]
 
-use std::ops::Generator;
-use std::ops::GeneratorState;
+use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
 
 fn main() {
     let _generator = || {
@@ -12,7 +11,7 @@ fn main() {
             yield 2;
         };
 
-        match unsafe { sub_generator.resume() } {
+        match Pin::new(&mut sub_generator).resume() {
             GeneratorState::Yielded(x) => {
                 yield x;
             }
diff --git a/src/test/run-pass/generator/non-static-is-unpin.rs b/src/test/run-pass/generator/non-static-is-unpin.rs
new file mode 100644
index 0000000000000..96d0a8e283372
--- /dev/null
+++ b/src/test/run-pass/generator/non-static-is-unpin.rs
@@ -0,0 +1,18 @@
+// run-pass
+
+#![feature(generators, generator_trait)]
+
+use std::marker::{PhantomPinned, Unpin};
+
+fn assert_unpin<G: Unpin>(_: G) {
+}
+
+fn main() {
+    // Even though this generator holds a `PhantomPinned` in its environment, it
+    // remains `Unpin`.
+    assert_unpin(|| {
+        let pinned = PhantomPinned;
+        yield;
+        drop(pinned);
+    });
+}
diff --git a/src/test/run-pass/generator/panic-drops.rs b/src/test/run-pass/generator/panic-drops.rs
index ce12f4225ef0a..5ac97585f4b57 100644
--- a/src/test/run-pass/generator/panic-drops.rs
+++ b/src/test/run-pass/generator/panic-drops.rs
@@ -6,9 +6,10 @@
 
 use std::ops::Generator;
 use std::panic;
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::pin::Pin;
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static A: AtomicUsize = ATOMIC_USIZE_INIT;
+static A: AtomicUsize = AtomicUsize::new(0);
 
 struct B;
 
@@ -34,7 +35,7 @@ fn main() {
 
     assert_eq!(A.load(Ordering::SeqCst), 0);
     let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-        unsafe { foo.resume() }
+        Pin::new(&mut foo).resume()
     }));
     assert!(res.is_err());
     assert_eq!(A.load(Ordering::SeqCst), 1);
@@ -49,7 +50,7 @@ fn main() {
 
     assert_eq!(A.load(Ordering::SeqCst), 1);
     let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-        unsafe { foo.resume() }
+        Pin::new(&mut foo).resume()
     }));
     assert!(res.is_err());
     assert_eq!(A.load(Ordering::SeqCst), 1);
diff --git a/src/test/run-pass/generator/panic-safe.rs b/src/test/run-pass/generator/panic-safe.rs
index 134debdd23bc5..5f6778674dce1 100644
--- a/src/test/run-pass/generator/panic-safe.rs
+++ b/src/test/run-pass/generator/panic-safe.rs
@@ -5,6 +5,7 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 use std::panic;
 
 fn main() {
@@ -16,13 +17,13 @@ fn main() {
     };
 
     let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-        unsafe { foo.resume() }
+        Pin::new(&mut foo).resume()
     }));
     assert!(res.is_err());
 
     for _ in 0..10 {
         let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
-            unsafe { foo.resume() }
+            Pin::new(&mut foo).resume()
         }));
         assert!(res.is_err());
     }
diff --git a/src/test/run-pass/generator/pin-box-generator.rs b/src/test/run-pass/generator/pin-box-generator.rs
new file mode 100644
index 0000000000000..c3136f5c0ec82
--- /dev/null
+++ b/src/test/run-pass/generator/pin-box-generator.rs
@@ -0,0 +1,13 @@
+// run-pass
+
+#![feature(generators, generator_trait)]
+
+use std::ops::Generator;
+
+fn assert_generator<G: Generator>(_: G) {
+}
+
+fn main() {
+    assert_generator(static || yield);
+    assert_generator(Box::pin(static || yield));
+}
diff --git a/src/test/run-pass/generator/resume-after-return.rs b/src/test/run-pass/generator/resume-after-return.rs
index 2213c2f3fbae3..71a68ff684af3 100644
--- a/src/test/run-pass/generator/resume-after-return.rs
+++ b/src/test/run-pass/generator/resume-after-return.rs
@@ -5,6 +5,7 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
 use std::panic;
 
 fn main() {
@@ -15,12 +16,12 @@ fn main() {
         yield;
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
 
-    match panic::catch_unwind(move || unsafe { foo.resume() }) {
+    match panic::catch_unwind(move || Pin::new(&mut foo).resume()) {
         Ok(_) => panic!("generator successfully resumed"),
         Err(_) => {}
     }
diff --git a/src/test/run-pass/generator/smoke.rs b/src/test/run-pass/generator/smoke.rs
index 8582941d610ca..533f2399084fa 100644
--- a/src/test/run-pass/generator/smoke.rs
+++ b/src/test/run-pass/generator/smoke.rs
@@ -6,6 +6,7 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
 use std::thread;
 
 #[test]
@@ -16,7 +17,7 @@ fn simple() {
         }
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -32,7 +33,7 @@ fn return_capture() {
         a
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(ref s) if *s == "foo" => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -44,11 +45,11 @@ fn simple_yield() {
         yield;
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Yielded(()) => {}
         s => panic!("bad state: {:?}", s),
     }
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -61,11 +62,11 @@ fn yield_capture() {
         yield b;
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Yielded(ref s) if *s == "foo" => {}
         s => panic!("bad state: {:?}", s),
     }
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -78,11 +79,11 @@ fn simple_yield_value() {
         return String::from("foo")
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Yielded(ref s) if *s == "bar" => {}
         s => panic!("bad state: {:?}", s),
     }
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(ref s) if *s == "foo" => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -96,11 +97,11 @@ fn return_after_yield() {
         return a
     };
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Yielded(()) => {}
         s => panic!("bad state: {:?}", s),
     }
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(ref s) if *s == "foo" => {}
         s => panic!("bad state: {:?}", s),
     }
@@ -148,11 +149,11 @@ fn send_and_sync() {
 fn send_over_threads() {
     let mut foo = || { yield };
     thread::spawn(move || {
-        match unsafe { foo.resume() } {
+        match Pin::new(&mut foo).resume() {
             GeneratorState::Yielded(()) => {}
             s => panic!("bad state: {:?}", s),
         }
-        match unsafe { foo.resume() } {
+        match Pin::new(&mut foo).resume() {
             GeneratorState::Complete(()) => {}
             s => panic!("bad state: {:?}", s),
         }
@@ -161,11 +162,11 @@ fn send_over_threads() {
     let a = String::from("a");
     let mut foo = || { yield a };
     thread::spawn(move || {
-        match unsafe { foo.resume() } {
+        match Pin::new(&mut foo).resume() {
             GeneratorState::Yielded(ref s) if *s == "a" => {}
             s => panic!("bad state: {:?}", s),
         }
-        match unsafe { foo.resume() } {
+        match Pin::new(&mut foo).resume() {
             GeneratorState::Complete(()) => {}
             s => panic!("bad state: {:?}", s),
         }
diff --git a/src/test/run-pass/generator/static-generators.rs b/src/test/run-pass/generator/static-generators.rs
index eeaba3fe3c4c3..965d3c61c22d5 100644
--- a/src/test/run-pass/generator/static-generators.rs
+++ b/src/test/run-pass/generator/static-generators.rs
@@ -2,6 +2,7 @@
 
 #![feature(generators, generator_trait)]
 
+use std::pin::Pin;
 use std::ops::{Generator, GeneratorState};
 
 fn main() {
@@ -11,8 +12,9 @@ fn main() {
         yield;
         assert_eq!(b as *const _, &a as *const _);
     };
-    unsafe {
-        assert_eq!(generator.resume(), GeneratorState::Yielded(()));
-        assert_eq!(generator.resume(), GeneratorState::Complete(()));
-    }
+    // Safety: We shadow the original generator variable so have no safe API to
+    // move it after this point.
+    let mut generator = unsafe { Pin::new_unchecked(&mut generator) };
+    assert_eq!(generator.as_mut().resume(), GeneratorState::Yielded(()));
+    assert_eq!(generator.as_mut().resume(), GeneratorState::Complete(()));
 }
diff --git a/src/test/run-pass/generator/xcrate-reachable.rs b/src/test/run-pass/generator/xcrate-reachable.rs
index 403c920786e9c..9483ad7395ea1 100644
--- a/src/test/run-pass/generator/xcrate-reachable.rs
+++ b/src/test/run-pass/generator/xcrate-reachable.rs
@@ -7,7 +7,8 @@
 extern crate xcrate_reachable as foo;
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
-    unsafe { foo::foo().resume(); }
+    Pin::new(&mut foo::foo()).resume();
 }
diff --git a/src/test/run-pass/generator/xcrate.rs b/src/test/run-pass/generator/xcrate.rs
index 571b8fa9170f4..febf5c3583f30 100644
--- a/src/test/run-pass/generator/xcrate.rs
+++ b/src/test/run-pass/generator/xcrate.rs
@@ -7,22 +7,23 @@
 extern crate xcrate;
 
 use std::ops::{GeneratorState, Generator};
+use std::pin::Pin;
 
 fn main() {
     let mut foo = xcrate::foo();
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
 
     let mut foo = xcrate::bar(3);
 
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Yielded(3) => {}
         s => panic!("bad state: {:?}", s),
     }
-    match unsafe { foo.resume() } {
+    match Pin::new(&mut foo).resume() {
         GeneratorState::Complete(()) => {}
         s => panic!("bad state: {:?}", s),
     }
diff --git a/src/test/run-pass/issues/issue-34053.rs b/src/test/run-pass/issues/issue-34053.rs
index ec5a0cbf6bbd5..fa23ae8f95bee 100644
--- a/src/test/run-pass/issues/issue-34053.rs
+++ b/src/test/run-pass/issues/issue-34053.rs
@@ -1,7 +1,7 @@
 // run-pass
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
-static DROP_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
+static DROP_COUNTER: AtomicUsize = AtomicUsize::new(0);
 
 struct A(i32);
 
diff --git a/src/test/run-pass/issues/issue-7012.rs b/src/test/run-pass/issues/issue-7012.rs
index a1c4bf83beb34..90eba1706956d 100644
--- a/src/test/run-pass/issues/issue-7012.rs
+++ b/src/test/run-pass/issues/issue-7012.rs
@@ -5,7 +5,7 @@
 /*
 # Comparison of static arrays
 
-The expected behaviour would be that test==test1, therefore 'true'
+The expected behaviour would be that `test == test1`, therefore 'true'
 would be printed, however the below prints false.
 */
 
diff --git a/src/test/run-pass/item-attributes.rs b/src/test/run-pass/item-attributes.rs
index 52b931f638c09..e3ed350f29a94 100644
--- a/src/test/run-pass/item-attributes.rs
+++ b/src/test/run-pass/item-attributes.rs
@@ -163,7 +163,7 @@ mod test_foreign_items {
 }
 
 
-// FIXME #623 - these aren't supported yet
+// FIXME(#623): - these aren't supported yet
 /*mod test_literals {
     #![str = "s"]
     #![char = 'c']
diff --git a/src/test/run-pass/macros/macro-follow.rs b/src/test/run-pass/macros/macro-follow.rs
index f90afce90ee30..488339b025dce 100644
--- a/src/test/run-pass/macros/macro-follow.rs
+++ b/src/test/run-pass/macros/macro-follow.rs
@@ -73,7 +73,7 @@ macro_rules! follow_block {
     ($b:block $t:ty) => {};
     ($b:block $s:stmt) => {};
     ($b:block $p:path) => {};
-    ($b:block $b:block) => {};
+    ($b:block $c:block) => {};
     ($b:block $i:ident) => {};
     ($b:block $t:tt) => {};
     ($b:block $i:item) => {};
@@ -99,9 +99,9 @@ macro_rules! follow_ident {
     ($i:ident $s:stmt) => {};
     ($i:ident $p:path) => {};
     ($i:ident $b:block) => {};
-    ($i:ident $i:ident) => {};
+    ($i:ident $j:ident) => {};
     ($i:ident $t:tt) => {};
-    ($i:ident $i:item) => {};
+    ($i:ident $j:item) => {};
     ($i:ident $m:meta) => {};
 }
 // FOLLOW(tt) = any token
@@ -120,12 +120,12 @@ macro_rules! follow_tt {
     ($t:tt ident) => {};
     ($t:tt $p:pat) => {};
     ($t:tt $e:expr) => {};
-    ($t:tt $t:ty) => {};
+    ($t:tt $v:ty) => {};
     ($t:tt $s:stmt) => {};
     ($t:tt $p:path) => {};
     ($t:tt $b:block) => {};
     ($t:tt $i:ident) => {};
-    ($t:tt $t:tt) => {};
+    ($t:tt $v:tt) => {};
     ($t:tt $i:item) => {};
     ($t:tt $m:meta) => {};
 }
@@ -149,9 +149,9 @@ macro_rules! follow_item {
     ($i:item $s:stmt) => {};
     ($i:item $p:path) => {};
     ($i:item $b:block) => {};
-    ($i:item $i:ident) => {};
+    ($i:item $j:ident) => {};
     ($i:item $t:tt) => {};
-    ($i:item $i:item) => {};
+    ($i:item $j:item) => {};
     ($i:item $m:meta) => {};
 }
 // FOLLOW(meta) = any token
@@ -177,7 +177,7 @@ macro_rules! follow_meta {
     ($m:meta $i:ident) => {};
     ($m:meta $t:tt) => {};
     ($m:meta $i:item) => {};
-    ($m:meta $m:meta) => {};
+    ($m:meta $n:meta) => {};
 }
 
 fn main() {}
diff --git a/src/test/run-pass/methods/method-probe-no-guessing-dyn-trait.rs b/src/test/run-pass/methods/method-probe-no-guessing-dyn-trait.rs
new file mode 100644
index 0000000000000..8c8165a100449
--- /dev/null
+++ b/src/test/run-pass/methods/method-probe-no-guessing-dyn-trait.rs
@@ -0,0 +1,59 @@
+// Check that method matching does not make "guesses" depending on
+// Deref impls that don't eventually end up being picked.
+
+use std::ops::Deref;
+
+// An impl with less derefs will get called over an impl with more derefs,
+// so `(t: Foo<_>).my_fn()` will use `<Foo<u32> as MyTrait1>::my_fn(t)`,
+// and does *not* force the `_` to equal `()`, because the Deref impl
+// was *not* used.
+
+trait MyTrait1 {
+    fn my_fn(&self) {}
+}
+
+impl MyTrait1 for Foo<u32> {}
+
+struct Foo<T>(T);
+
+impl Deref for Foo<()> {
+    type Target = dyn MyTrait1 + 'static;
+    fn deref(&self) -> &(dyn MyTrait1 + 'static) {
+        panic!()
+    }
+}
+
+// ...but if there is no impl with less derefs, the "guess" will be
+// forced, so `(t: Bar<_>).my_fn2()` is `<dyn MyTrait2 as MyTrait2>::my_fn2(*t)`,
+// and because the deref impl is used, the `_` is forced to equal `u8`.
+
+trait MyTrait2 {
+    fn my_fn2(&self) {}
+}
+
+impl MyTrait2 for u32 {}
+struct Bar<T>(T, u32);
+impl Deref for Bar<u8> {
+    type Target = dyn MyTrait2 + 'static;
+    fn deref(&self) -> &(dyn MyTrait2 + 'static) {
+        &self.1
+    }
+}
+
+// actually invoke things
+
+fn main() {
+    let mut foo: Option<Foo<_>> = None;
+    let mut bar: Option<Bar<_>> = None;
+    let mut first_iter = true;
+    loop {
+        if !first_iter {
+            foo.as_ref().unwrap().my_fn();
+            bar.as_ref().unwrap().my_fn2();
+            break;
+        }
+        foo = Some(Foo(0));
+        bar = Some(Bar(Default::default(), 0));
+        first_iter = false;
+    }
+}
diff --git a/src/test/run-pass/mir/mir_fat_ptr_drop.rs b/src/test/run-pass/mir/mir_fat_ptr_drop.rs
index 9f4f3d6c5d306..d865c3499b270 100644
--- a/src/test/run-pass/mir/mir_fat_ptr_drop.rs
+++ b/src/test/run-pass/mir/mir_fat_ptr_drop.rs
@@ -10,7 +10,7 @@
 use std::sync::atomic;
 use std::sync::atomic::Ordering::SeqCst;
 
-static COUNTER: atomic::AtomicUsize = atomic::ATOMIC_USIZE_INIT;
+static COUNTER: atomic::AtomicUsize = atomic::AtomicUsize::new(0);
 
 struct DropMe {
 }
diff --git a/src/test/run-pass/monomorphize-abi-alignment.rs b/src/test/run-pass/monomorphize-abi-alignment.rs
index b55974e64210a..a26f324f7dc05 100644
--- a/src/test/run-pass/monomorphize-abi-alignment.rs
+++ b/src/test/run-pass/monomorphize-abi-alignment.rs
@@ -2,7 +2,7 @@
 /*!
  * On x86_64-linux-gnu and possibly other platforms, structs get 8-byte "preferred" alignment,
  * but their "ABI" alignment (i.e., what actually matters for data layout) is the largest alignment
- * of any field.  (Also, u64 has 8-byte ABI alignment; this is not always true).
+ * of any field. (Also, `u64` has 8-byte ABI alignment; this is not always true).
  *
  * On such platforms, if monomorphize uses the "preferred" alignment, then it will unify
  * `A` and `B`, even though `S<A>` and `S<B>` have the field `t` at different offsets,
diff --git a/src/test/run-pass/numbers-arithmetic/num-wrapping.rs b/src/test/run-pass/numbers-arithmetic/num-wrapping.rs
index d7ab51f8649c3..9a01549ecd24e 100644
--- a/src/test/run-pass/numbers-arithmetic/num-wrapping.rs
+++ b/src/test/run-pass/numbers-arithmetic/num-wrapping.rs
@@ -175,7 +175,7 @@ fn test_op_assigns() {
                 assert_eq!(black_box(tmp), Wrapping($ans));
             }
 
-            // FIXME(30524): Uncomment this test
+            // FIXME(30524): uncomment this test
             /*
             {
                 let mut tmp = Wrapping($initial);
diff --git a/src/test/run-pass/panic-uninitialized-zeroed.rs b/src/test/run-pass/panic-uninitialized-zeroed.rs
index d47ff6c630d11..31c0d2994d415 100644
--- a/src/test/run-pass/panic-uninitialized-zeroed.rs
+++ b/src/test/run-pass/panic-uninitialized-zeroed.rs
@@ -36,7 +36,7 @@ fn main() {
 
         assert_eq!(
             panic::catch_unwind(|| {
-                mem::MaybeUninit::<!>::uninitialized().into_inner()
+                mem::MaybeUninit::<!>::uninitialized().into_initialized()
             }).err().and_then(|a| a.downcast_ref::<String>().map(|s| {
                 s == "Attempted to instantiate uninhabited type !"
             })),
@@ -63,7 +63,7 @@ fn main() {
 
         assert_eq!(
             panic::catch_unwind(|| {
-                mem::MaybeUninit::<Foo>::uninitialized().into_inner()
+                mem::MaybeUninit::<Foo>::uninitialized().into_initialized()
             }).err().and_then(|a| a.downcast_ref::<String>().map(|s| {
                 s == "Attempted to instantiate uninhabited type Foo"
             })),
@@ -90,7 +90,7 @@ fn main() {
 
         assert_eq!(
             panic::catch_unwind(|| {
-                mem::MaybeUninit::<Bar>::uninitialized().into_inner()
+                mem::MaybeUninit::<Bar>::uninitialized().into_initialized()
             }).err().and_then(|a| a.downcast_ref::<String>().map(|s| {
                 s == "Attempted to instantiate uninhabited type Bar"
             })),
diff --git a/src/test/run-pass/panics/panic-recover-propagate.rs b/src/test/run-pass/panics/panic-recover-propagate.rs
index 0a15417f72a4e..7969336ca749b 100644
--- a/src/test/run-pass/panics/panic-recover-propagate.rs
+++ b/src/test/run-pass/panics/panic-recover-propagate.rs
@@ -1,11 +1,11 @@
 // run-pass
 // ignore-emscripten no threads support
 
-use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::panic;
 use std::thread;
 
-static A: AtomicUsize = ATOMIC_USIZE_INIT;
+static A: AtomicUsize = AtomicUsize::new(0);
 
 fn main() {
     panic::set_hook(Box::new(|_| {
diff --git a/src/test/run-pass/simd/simd-intrinsic-generic-bitmask.rs b/src/test/run-pass/simd/simd-intrinsic-generic-bitmask.rs
new file mode 100644
index 0000000000000..b28f742a92e94
--- /dev/null
+++ b/src/test/run-pass/simd/simd-intrinsic-generic-bitmask.rs
@@ -0,0 +1,61 @@
+// run-pass
+#![allow(non_camel_case_types)]
+
+// ignore-emscripten
+
+// Test that the simd_bitmask intrinsic produces correct results.
+
+#![feature(repr_simd, platform_intrinsics)]
+#[allow(non_camel_case_types)]
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct u32x4(pub u32, pub u32, pub u32, pub u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct u8x4(pub u8, pub u8, pub u8, pub u8);
+
+#[repr(simd)]
+#[derive(Copy, Clone, PartialEq, Debug)]
+struct Tx4<T>(pub T, pub T, pub T, pub T);
+
+extern "platform-intrinsic" {
+    fn simd_bitmask<T, U>(x: T) -> U;
+}
+
+fn main() {
+    let z = u32x4(0, 0, 0, 0);
+    let ez = 0_u8;
+
+    let o = u32x4(!0, !0, !0, !0);
+    let eo = 0b_1111_u8;
+
+    let m0 = u32x4(!0, 0, !0, 0);
+    let e0 = 0b_0000_0101_u8;
+
+    // Check that the MSB is extracted:
+    let m = u8x4(0b_1000_0000, 0b_0100_0001, 0b_1100_0001, 0b_1111_1111);
+    let e = 0b_1101;
+
+    // Check usize / isize
+    let msize: Tx4<usize> = Tx4(usize::max_value(), 0, usize::max_value(), usize::max_value());
+
+    unsafe {
+        let r: u8 = simd_bitmask(z);
+        assert_eq!(r, ez);
+
+        let r: u8 = simd_bitmask(o);
+        assert_eq!(r, eo);
+
+        let r: u8 = simd_bitmask(m0);
+        assert_eq!(r, e0);
+
+        let r: u8 = simd_bitmask(m);
+        assert_eq!(r, e);
+
+        let r: u8 = simd_bitmask(msize);
+        assert_eq!(r, e);
+
+    }
+}
diff --git a/src/test/run-pass/simd/simd-intrinsic-generic-reduction.rs b/src/test/run-pass/simd/simd-intrinsic-generic-reduction.rs
index b39f54a5efbb4..e3faa7c625ccc 100644
--- a/src/test/run-pass/simd/simd-intrinsic-generic-reduction.rs
+++ b/src/test/run-pass/simd/simd-intrinsic-generic-reduction.rs
@@ -2,6 +2,7 @@
 #![allow(non_camel_case_types)]
 
 // ignore-emscripten
+// ignore-aarch64 FIXME: https://github.com/rust-lang/rust/issues/54510
 
 // Test that the simd_reduce_{op} intrinsics produce the correct results.
 
diff --git a/src/test/run-pass/structs-enums/align-enum.rs b/src/test/run-pass/structs-enums/align-enum.rs
new file mode 100644
index 0000000000000..8d72b1f6f0d24
--- /dev/null
+++ b/src/test/run-pass/structs-enums/align-enum.rs
@@ -0,0 +1,55 @@
+// run-pass
+#![allow(dead_code)]
+#![feature(repr_align_enum)]
+
+use std::mem;
+
+// Raising alignment
+#[repr(align(16))]
+enum Align16 {
+    Foo { foo: u32 },
+    Bar { bar: u32 },
+}
+
+// Raise alignment by maximum
+#[repr(align(1), align(16))]
+#[repr(align(32))]
+#[repr(align(4))]
+enum Align32 {
+    Foo,
+    Bar,
+}
+
+// Not reducing alignment
+#[repr(align(4))]
+enum AlsoAlign16 {
+    Foo { limb_with_align16: Align16 },
+    Bar,
+}
+
+// No niche for discriminant when used as limb
+#[repr(align(16))]
+struct NoNiche16(u64, u64);
+
+// Discriminant will require extra space, but enum needs to stay compatible
+// with alignment 16
+#[repr(align(1))]
+enum AnotherAlign16 {
+    Foo { limb_with_noniche16: NoNiche16 },
+    Bar,
+    Baz,
+}
+
+fn main() {
+    assert_eq!(mem::align_of::<Align16>(), 16);
+    assert_eq!(mem::size_of::<Align16>(), 16);
+
+    assert_eq!(mem::align_of::<Align32>(), 32);
+    assert_eq!(mem::size_of::<Align32>(), 32);
+
+    assert_eq!(mem::align_of::<AlsoAlign16>(), 16);
+    assert_eq!(mem::size_of::<AlsoAlign16>(), 16);
+
+    assert_eq!(mem::align_of::<AnotherAlign16>(), 16);
+    assert_eq!(mem::size_of::<AnotherAlign16>(), 32);
+}
diff --git a/src/test/run-pass/threads-sendsync/sync-send-iterators-in-libcore.rs b/src/test/run-pass/threads-sendsync/sync-send-iterators-in-libcore.rs
index 903bbf5163443..44beb9dc1e534 100644
--- a/src/test/run-pass/threads-sendsync/sync-send-iterators-in-libcore.rs
+++ b/src/test/run-pass/threads-sendsync/sync-send-iterators-in-libcore.rs
@@ -2,9 +2,6 @@
 // pretty-expanded FIXME #23616
 
 #![allow(warnings)]
-#![feature(iter_empty)]
-#![feature(iter_once)]
-#![feature(str_escape)]
 
 use std::iter::{empty, once, repeat};
 
diff --git a/src/test/run-pass/threads-sendsync/tls-init-on-init.rs b/src/test/run-pass/threads-sendsync/tls-init-on-init.rs
index 6ac7a9253cdd3..193c18151059a 100644
--- a/src/test/run-pass/threads-sendsync/tls-init-on-init.rs
+++ b/src/test/run-pass/threads-sendsync/tls-init-on-init.rs
@@ -6,13 +6,13 @@
 #![feature(thread_local_try_with)]
 
 use std::thread;
-use std::sync::atomic::{AtomicUsize, Ordering, ATOMIC_USIZE_INIT};
+use std::sync::atomic::{AtomicUsize, Ordering};
 
 struct Foo { cnt: usize }
 
 thread_local!(static FOO: Foo = Foo::init());
 
-static CNT: AtomicUsize = ATOMIC_USIZE_INIT;
+static CNT: AtomicUsize = AtomicUsize::new(0);
 
 impl Foo {
     fn init() -> Foo {
diff --git a/src/test/run-pass/try_from.rs b/src/test/run-pass/try_from.rs
new file mode 100644
index 0000000000000..4522ce3a8d617
--- /dev/null
+++ b/src/test/run-pass/try_from.rs
@@ -0,0 +1,37 @@
+// This test relies on `TryFrom` being blanket impl for all `T: Into`
+// and `TryInto` being blanket impl for all `U: TryFrom`
+
+// This test was added to show the motivation for doing this
+// over `TryFrom` being blanket impl for all `T: From`
+
+#![feature(try_from, never_type)]
+
+use std::convert::TryInto;
+
+struct Foo<T> {
+    t: T,
+}
+
+// This fails to compile due to coherence restrictions
+// as of Rust version 1.32.x, therefore it could not be used
+// instead of the `Into` version of the impl, and serves as
+// motivation for a blanket impl for all `T: Into`, instead
+// of a blanket impl for all `T: From`
+/*
+impl<T> From<Foo<T>> for Box<T> {
+    fn from(foo: Foo<T>) -> Box<T> {
+        Box::new(foo.t)
+    }
+}
+*/
+
+impl<T> Into<Vec<T>> for Foo<T> {
+    fn into(self) -> Vec<T> {
+        vec![self.t]
+    }
+}
+
+pub fn main() {
+    let _: Result<Vec<i32>, !> = Foo { t: 10 }.try_into();
+}
+
diff --git a/src/test/run-pass/weird-exprs.rs b/src/test/run-pass/weird-exprs.rs
index 6d0c5c11732f2..7ce7e29e87235 100644
--- a/src/test/run-pass/weird-exprs.rs
+++ b/src/test/run-pass/weird-exprs.rs
@@ -4,7 +4,7 @@
 #![allow(unused_parens)]
 // compile-flags: -Z borrowck=compare
 
-#![recursion_limit = "128"]
+#![recursion_limit = "256"]
 
 use std::cell::Cell;
 use std::mem::swap;
diff --git a/src/test/rustdoc-js/substring.js b/src/test/rustdoc-js/substring.js
deleted file mode 100644
index 3a6750151f7d8..0000000000000
--- a/src/test/rustdoc-js/substring.js
+++ /dev/null
@@ -1,10 +0,0 @@
-// exact-check
-
-const QUERY = 'waker_from';
-
-const EXPECTED = {
-    'others': [
-        { 'path': 'std::task', 'name': 'local_waker_from_nonlocal' },
-        { 'path': 'alloc::task', 'name': 'local_waker_from_nonlocal' },
-    ],
-};
diff --git a/src/test/rustdoc-ui/failed-doctest-output.stdout b/src/test/rustdoc-ui/failed-doctest-output.stdout
index d584845e1f2ed..b7617ec556d20 100644
--- a/src/test/rustdoc-ui/failed-doctest-output.stdout
+++ b/src/test/rustdoc-ui/failed-doctest-output.stdout
@@ -12,7 +12,7 @@ error[E0425]: cannot find value `no` in this scope
 3 | no
   | ^^ not found in this scope
 
-thread '$DIR/failed-doctest-output.rs - OtherStruct (line 17)' panicked at 'couldn't compile the test', src/librustdoc/test.rs:319:13
+thread '$DIR/failed-doctest-output.rs - OtherStruct (line 17)' panicked at 'couldn't compile the test', src/librustdoc/test.rs:351:13
 note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
 
 ---- $DIR/failed-doctest-output.rs - SomeStruct (line 11) stdout ----
@@ -21,7 +21,7 @@ thread '$DIR/failed-doctest-output.rs - SomeStruct (line 11)' panicked at 'test
 thread 'main' panicked at 'oh no', $DIR/failed-doctest-output.rs:3:1
 note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
 
-', src/librustdoc/test.rs:354:17
+', src/librustdoc/test.rs:372:17
 
 
 failures:
diff --git a/src/test/rustdoc-ui/invalid-syntax.rs b/src/test/rustdoc-ui/invalid-syntax.rs
index 537816be8d735..924e0386d3191 100644
--- a/src/test/rustdoc-ui/invalid-syntax.rs
+++ b/src/test/rustdoc-ui/invalid-syntax.rs
@@ -1,7 +1,66 @@
 // compile-pass
-// compile-flags: --error-format=human
 
 /// ```
 /// \__________pkt->size___________/          \_result->size_/ \__pkt->size__/
 /// ```
 pub fn foo() {}
+
+/// ```
+///    |
+/// LL | use foobar::Baz;
+///    |     ^^^^^^ did you mean `baz::foobar`?
+/// ```
+pub fn bar() {}
+
+/// ```
+/// valid
+/// ```
+///
+/// ```
+/// \_
+/// ```
+///
+/// ```text
+/// "invalid
+/// ```
+pub fn valid_and_invalid() {}
+
+/// This is a normal doc comment, but...
+///
+/// There's a code block with bad syntax in it:
+///
+/// ```rust
+/// \_
+/// ```
+///
+/// Good thing we tested it!
+pub fn baz() {}
+
+/// Indented block start
+///
+///     code with bad syntax
+///     \_
+///
+/// Indented block end
+pub fn quux() {}
+
+/// Unclosed fence
+///
+/// ```
+/// slkdjf
+pub fn xyzzy() {}
+
+/// Indented code that contains a fence
+///
+///     ```
+pub fn blah() {}
+
+/// ```edition2018
+/// \_
+/// ```
+pub fn blargh() {}
+
+#[doc = "```"]
+/// \_
+#[doc = "```"]
+pub fn crazy_attrs() {}
diff --git a/src/test/rustdoc-ui/invalid-syntax.stderr b/src/test/rustdoc-ui/invalid-syntax.stderr
index b5661332e8d0e..10800380a05d3 100644
--- a/src/test/rustdoc-ui/invalid-syntax.stderr
+++ b/src/test/rustdoc-ui/invalid-syntax.stderr
@@ -1,10 +1,97 @@
-Output from rustc:
-error: unknown start of token: /
- --> <stdin>:1:1
-  |
-1 | /__________pkt->size___________/          /_result->size_/ /__pkt->size__/
-  | ^
-
-warning: Invalid doc comment starting with: `/__________pkt->size___________/          /_result->size_/ /__pkt->size__/`
-(Ignoring this codeblock)
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:3:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | /// /__________pkt->size___________/          /_result->size_/ /__pkt->size__/
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:8:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | ///    |
+LL | | /// LL | use foobar::Baz;
+LL | | ///    |     ^^^^^^ did you mean `baz::foobar`?
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: `
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:19:5
+   |
+LL |   /// ```
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+help: mark blocks that do not contain Rust code as text
+   |
+LL | /// ```text
+   |     ^^^^^^^
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:32:5
+   |
+LL |   /// ```rust
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:41:9
+   |
+LL |   ///     code with bad syntax
+   |  _________^
+LL | | ///     /_
+   | |__________^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:55:9
+   |
+LL | ///     ```
+   |         ^^^
+   |
+   = note: error from rustc: unknown start of token: `
+
+warning: could not parse code block as Rust code
+  --> $DIR/invalid-syntax.rs:58:5
+   |
+LL |   /// ```edition2018
+   |  _____^
+LL | | /// /_
+LL | | /// ```
+   | |_______^
+   |
+   = note: error from rustc: unknown start of token: /
+
+warning: doc comment contains an invalid Rust code block
+  --> $DIR/invalid-syntax.rs:63:1
+   |
+LL | / #[doc = "```"]
+LL | | /// /_
+LL | | #[doc = "```"]
+   | |______________^
+   |
+   = help: mark blocks that do not contain Rust code as text: ```text
 
diff --git a/src/test/rustdoc/async-fn.rs b/src/test/rustdoc/async-fn.rs
index a0b6c29126092..ba4997a7f9b5b 100644
--- a/src/test/rustdoc/async-fn.rs
+++ b/src/test/rustdoc/async-fn.rs
@@ -1,14 +1,35 @@
 // edition:2018
-// compile-flags:-Z unstable-options
-
-// FIXME: once `--edition` is stable in rustdoc, remove that `compile-flags` directive
 
 #![feature(async_await, futures_api)]
 
-// @has async_fn/struct.S.html
-// @has - '//code' 'pub async fn f()'
-pub struct S;
+// @has async_fn/fn.foo.html '//pre[@class="rust fn"]' 'pub async fn foo() -> Option<Foo>'
+pub async fn foo() -> Option<Foo> {
+    None
+}
+
+// @has async_fn/fn.bar.html '//pre[@class="rust fn"]' 'pub async fn bar(a: i32, b: i32) -> i32'
+pub async fn bar(a: i32, b: i32) -> i32 {
+    0
+}
+
+// @has async_fn/fn.baz.html '//pre[@class="rust fn"]' 'pub async fn baz<T>(a: T) -> T'
+pub async fn baz<T>(a: T) -> T {
+    a
+}
+
+trait Bar {}
+
+impl Bar for () {}
+
+// @has async_fn/fn.quux.html '//pre[@class="rust fn"]' 'pub async fn quux() -> impl Bar'
+pub async fn quux() -> impl Bar {
+    ()
+}
+
+// @has async_fn/struct.Foo.html
+// @matches - '//code' 'pub async fn f\(\)$'
+pub struct Foo;
 
-impl S {
+impl Foo {
     pub async fn f() {}
 }
diff --git a/src/test/rustdoc/auxiliary/enum_primitive.rs b/src/test/rustdoc/auxiliary/enum_primitive.rs
index eff47e8d8dde9..ed1da253a9732 100644
--- a/src/test/rustdoc/auxiliary/enum_primitive.rs
+++ b/src/test/rustdoc/auxiliary/enum_primitive.rs
@@ -22,7 +22,7 @@
 //! This crate exports a macro `enum_from_primitive!` that wraps an
 //! `enum` declaration and automatically adds an implementation of
 //! `num::FromPrimitive` (reexported here), to allow conversion from
-//! primitive integers to the enum.  It therefore provides an
+//! primitive integers to the enum. It therefore provides an
 //! alternative to the built-in `#[derive(FromPrimitive)]`, which
 //! requires the unstable `std::num::FromPrimitive` and is disabled in
 //! Rust 1.0.
diff --git a/src/test/rustdoc/bad-codeblock-syntax.rs b/src/test/rustdoc/bad-codeblock-syntax.rs
new file mode 100644
index 0000000000000..0ab2f68fcdebe
--- /dev/null
+++ b/src/test/rustdoc/bad-codeblock-syntax.rs
@@ -0,0 +1,27 @@
+// @has bad_codeblock_syntax/fn.foo.html
+// @has - '//*[@class="docblock"]/pre/code' '\_'
+/// ```
+/// \_
+/// ```
+pub fn foo() {}
+
+// @has bad_codeblock_syntax/fn.bar.html
+// @has - '//*[@class="docblock"]/pre/code' '`baz::foobar`'
+/// ```
+/// `baz::foobar`
+/// ```
+pub fn bar() {}
+
+// @has bad_codeblock_syntax/fn.quux.html
+// @has - '//*[@class="docblock"]/pre/code' '\_'
+/// ```rust
+/// \_
+/// ```
+pub fn quux() {}
+
+// @has bad_codeblock_syntax/fn.ok.html
+// @has - '//*[@class="docblock"]/pre/code[@class="language-text"]' '\_'
+/// ```text
+/// \_
+/// ```
+pub fn ok() {}
diff --git a/src/test/rustdoc/deprecated-future.rs b/src/test/rustdoc/deprecated-future.rs
index 383afe86cb405..c5248c52fb973 100644
--- a/src/test/rustdoc/deprecated-future.rs
+++ b/src/test/rustdoc/deprecated-future.rs
@@ -1,6 +1,8 @@
 #![feature(deprecated)]
 
+// @has deprecated_future/index.html '//*[@class="stab deprecated"]' \
+//      'Deprecated'
 // @has deprecated_future/struct.S.html '//*[@class="stab deprecated"]' \
-//      'Deprecating in 99.99.99: effectively never'
+//      'Deprecated since 99.99.99: effectively never'
 #[deprecated(since = "99.99.99", note = "effectively never")]
 pub struct S;
diff --git a/src/test/rustdoc/deprecated.rs b/src/test/rustdoc/deprecated.rs
index ca3f380ed2825..18a33438a2346 100644
--- a/src/test/rustdoc/deprecated.rs
+++ b/src/test/rustdoc/deprecated.rs
@@ -1,7 +1,9 @@
 #![feature(deprecated)]
 
-// @matches deprecated/index.html '//*[@class="docblock-short"]' \
-//      '^\[Deprecated\] Deprecated docs'
+// @has deprecated/index.html '//*[@class="docblock-short"]/span[@class="stab deprecated"]' \
+//      'Deprecated'
+// @has - '//*[@class="docblock-short"]' 'Deprecated docs'
+
 // @has deprecated/struct.S.html '//*[@class="stab deprecated"]' \
 //      'Deprecated since 1.0.0: text'
 /// Deprecated docs
@@ -26,3 +28,8 @@ pub struct V;
 //      'Deprecated$'
 #[deprecated]
 pub struct W;
+
+// @matches deprecated/struct.X.html '//*[@class="stab deprecated"]' \
+//      'Deprecated: shorthand reason$'
+#[deprecated = "shorthand reason"]
+pub struct X;
diff --git a/src/test/rustdoc/inline_cross/macros.rs b/src/test/rustdoc/inline_cross/macros.rs
index 4e370062385d0..f9bf982659e02 100644
--- a/src/test/rustdoc/inline_cross/macros.rs
+++ b/src/test/rustdoc/inline_cross/macros.rs
@@ -7,7 +7,8 @@
 
 extern crate macros;
 
-// @has foo/index.html '//*[@class="docblock-short"]' '[Deprecated] [Experimental]'
+// @has foo/index.html '//*[@class="docblock-short"]/span[@class="stab deprecated"]' Deprecated
+// @has - '//*[@class="docblock-short"]/span[@class="stab unstable"]' Experimental
 
 // @has foo/macro.my_macro.html
 // @has - '//*[@class="docblock"]' 'docs for my_macro'
diff --git a/src/test/rustdoc/internal.rs b/src/test/rustdoc/internal.rs
index ba58da138a8c0..2cb7c472cc84b 100644
--- a/src/test/rustdoc/internal.rs
+++ b/src/test/rustdoc/internal.rs
@@ -1,7 +1,9 @@
 // compile-flags: -Z force-unstable-if-unmarked
 
-// @matches internal/index.html '//*[@class="docblock-short"]' \
-//      '^\[Internal\] Docs'
+// @matches internal/index.html '//*[@class="docblock-short"]/span[@class="stab internal"]' \
+//      'Internal'
+// @matches - '//*[@class="docblock-short"]' 'Docs'
+
 // @has internal/struct.S.html '//*[@class="stab internal"]' \
 //      'This is an internal compiler API. (rustc_private)'
 /// Docs
diff --git a/src/test/rustdoc/issue-19190.rs b/src/test/rustdoc/issue-19190.rs
index a7c25538f7c44..c6bac51c5740d 100644
--- a/src/test/rustdoc/issue-19190.rs
+++ b/src/test/rustdoc/issue-19190.rs
@@ -1,3 +1,5 @@
+// compile-flags:-Z unstable-options --generate-redirect-pages
+
 use std::ops::Deref;
 
 pub struct Foo;
diff --git a/src/test/rustdoc/issue-21092.rs b/src/test/rustdoc/issue-21092.rs
index 14f547abd9a68..b054145a4831a 100644
--- a/src/test/rustdoc/issue-21092.rs
+++ b/src/test/rustdoc/issue-21092.rs
@@ -3,7 +3,6 @@
 
 extern crate issue_21092;
 
-// @has issue_21092/Bar.t.html
 // @has issue_21092/struct.Bar.html
 // @has - '//*[@id="associatedtype.Bar"]' 'type Bar = i32'
 pub use issue_21092::{Foo, Bar};
diff --git a/src/test/rustdoc/issue-27862.rs b/src/test/rustdoc/issue-27862.rs
index ce3978e7e9a8e..77522f1be2307 100644
--- a/src/test/rustdoc/issue-27862.rs
+++ b/src/test/rustdoc/issue-27862.rs
@@ -1,4 +1,4 @@
-/// Test  | Table
+/// Tests  | Table
 /// ------|-------------
 /// t = b | id = \|x\| x
 pub struct Foo; // @has issue_27862/struct.Foo.html //td 'id = |x| x'
diff --git a/src/test/rustdoc/issue-32374.rs b/src/test/rustdoc/issue-32374.rs
index 58876a1aa1162..7babfaf6060f4 100644
--- a/src/test/rustdoc/issue-32374.rs
+++ b/src/test/rustdoc/issue-32374.rs
@@ -3,8 +3,11 @@
 
 #![unstable(feature="test", issue = "32374")]
 
-// @matches issue_32374/index.html '//*[@class="docblock-short"]' \
-//      '^\[Deprecated\] \[Experimental\] Docs'
+// @matches issue_32374/index.html '//*[@class="docblock-short"]/span[@class="stab deprecated"]' \
+//      'Deprecated'
+// @matches issue_32374/index.html '//*[@class="docblock-short"]/span[@class="stab unstable"]' \
+//      'Experimental'
+// @matches issue_32374/index.html '//*[@class="docblock-short"]/text()' 'Docs'
 
 // @has issue_32374/struct.T.html '//*[@class="stab deprecated"]' \
 //      'Deprecated since 1.0.0: text'
diff --git a/src/test/rustdoc/issue-35169-2.rs b/src/test/rustdoc/issue-35169-2.rs
index 0caead100d666..33f7646ced68b 100644
--- a/src/test/rustdoc/issue-35169-2.rs
+++ b/src/test/rustdoc/issue-35169-2.rs
@@ -23,7 +23,6 @@ impl DerefMut for Bar {
     fn deref_mut(&mut self) -> &mut Foo { loop {} }
 }
 
-// @has issue_35169_2/Bar.t.html
 // @has issue_35169_2/struct.Bar.html
 // @has - '//*[@id="by_ref.v"]' 'fn by_ref(&self)'
 // @has - '//*[@id="method.by_ref"]' 'fn by_ref(&self)'
diff --git a/src/test/rustdoc/issue-35169.rs b/src/test/rustdoc/issue-35169.rs
index 0978b103076fe..04fffc40572a6 100644
--- a/src/test/rustdoc/issue-35169.rs
+++ b/src/test/rustdoc/issue-35169.rs
@@ -18,7 +18,6 @@ impl Deref for Bar {
     fn deref(&self) -> &Foo { loop {} }
 }
 
-// @has issue_35169/Bar.t.html
 // @has issue_35169/struct.Bar.html
 // @has - '//*[@id="by_ref.v"]' 'fn by_ref(&self)'
 // @has - '//*[@id="method.by_ref"]' 'fn by_ref(&self)'
diff --git a/src/test/rustdoc/issue-56701.rs b/src/test/rustdoc/issue-56701.rs
new file mode 100644
index 0000000000000..6fb30a4ff4c30
--- /dev/null
+++ b/src/test/rustdoc/issue-56701.rs
@@ -0,0 +1,34 @@
+// This shouldn't cause a stack overflow when rustdoc is run
+
+use std::ops::Deref;
+use std::ops::DerefMut;
+
+pub trait SimpleTrait {
+    type SimpleT;
+}
+
+impl<Inner: SimpleTrait, Outer: Deref<Target = Inner>> SimpleTrait for Outer {
+    type SimpleT = Inner::SimpleT;
+}
+
+pub trait AnotherTrait {
+    type AnotherT;
+}
+
+impl<T, Simple: SimpleTrait<SimpleT = Vec<T>>> AnotherTrait for Simple {
+    type AnotherT = T;
+}
+
+pub struct Unrelated<Inner, UnrelatedT: DerefMut<Target = Vec<Inner>>>(UnrelatedT);
+
+impl<Inner, UnrelatedT: DerefMut<Target = Vec<Inner>>> Deref for Unrelated<Inner, UnrelatedT> {
+    type Target = Vec<Inner>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+
+pub fn main() { }
+
diff --git a/src/test/rustdoc/keyword.rs b/src/test/rustdoc/keyword.rs
index d3327ae7ae117..c721c024468dd 100644
--- a/src/test/rustdoc/keyword.rs
+++ b/src/test/rustdoc/keyword.rs
@@ -7,7 +7,7 @@
 // @has foo/keyword.match.html '//a[@class="keyword"]' 'match'
 // @has foo/keyword.match.html '//span[@class="in-band"]' 'Keyword match'
 // @has foo/keyword.match.html '//section[@id="main"]//div[@class="docblock"]//p' 'this is a test!'
-// @!has foo/index.html '//a/@href' 'foo/index.html'
+// @has foo/index.html '//a/@href' '../foo/index.html'
 // @!has foo/foo/index.html
 // @!has-dir foo/foo
 #[doc(keyword = "match")]
diff --git a/src/test/rustdoc/macros.rs b/src/test/rustdoc/macros.rs
index c66a2c845bfd8..fb4f02ad16052 100644
--- a/src/test/rustdoc/macros.rs
+++ b/src/test/rustdoc/macros.rs
@@ -2,8 +2,6 @@
 // @has - //pre '() => { ... };'
 // @has - //pre '($a:tt) => { ... };'
 // @has - //pre '($e:expr) => { ... };'
-// @has macros/macro.my_macro!.html
-// @has - //a 'macro.my_macro.html'
 #[macro_export]
 macro_rules! my_macro {
     () => [];
diff --git a/src/test/rustdoc/proc-macro.rs b/src/test/rustdoc/proc-macro.rs
index d4d70d04f5b4e..1e396f1be0e04 100644
--- a/src/test/rustdoc/proc-macro.rs
+++ b/src/test/rustdoc/proc-macro.rs
@@ -4,6 +4,11 @@
 #![crate_type="proc-macro"]
 #![crate_name="some_macros"]
 
+// @has some_macros/index.html
+// @has - '//a/[@href="attr.some_proc_attr.html"]' 'some_proc_attr'
+
+//! include a link to [some_proc_attr] to make sure it works.
+
 extern crate proc_macro;
 
 use proc_macro::TokenStream;
diff --git a/src/test/rustdoc/process-termination.rs b/src/test/rustdoc/process-termination.rs
new file mode 100644
index 0000000000000..32258792b6e8b
--- /dev/null
+++ b/src/test/rustdoc/process-termination.rs
@@ -0,0 +1,24 @@
+// compile-flags:--test
+
+/// A check of using various process termination strategies
+///
+/// # Examples
+///
+/// ```rust
+/// assert!(true); // this returns `()`, all is well
+/// ```
+///
+/// You can also simply return `Ok(())`, but you'll need to disambiguate the
+/// type using turbofish, because we cannot infer the type:
+///
+/// ```rust
+/// Ok::<(), &'static str>(())
+/// ```
+///
+/// You can err with anything that implements `Debug`:
+///
+/// ```rust,should_panic
+/// Err("This is returned from `main`, leading to panic")?;
+/// Ok::<(), &'static str>(())
+/// ```
+pub fn check_process_termination() {}
diff --git a/src/test/rustdoc/rustc_deprecated-future.rs b/src/test/rustdoc/rustc_deprecated-future.rs
new file mode 100644
index 0000000000000..3133775706b8d
--- /dev/null
+++ b/src/test/rustdoc/rustc_deprecated-future.rs
@@ -0,0 +1,11 @@
+#![feature(staged_api)]
+
+#![stable(feature = "rustc_deprecated-future-test", since = "1.0.0")]
+
+// @has rustc_deprecated_future/index.html '//*[@class="stab deprecated"]' \
+//      'Deprecation planned'
+// @has rustc_deprecated_future/struct.S.html '//*[@class="stab deprecated"]' \
+//      'Deprecating in 99.99.99: effectively never'
+#[rustc_deprecated(since = "99.99.99", reason = "effectively never")]
+#[stable(feature = "rustc_deprecated-future-test", since = "1.0.0")]
+pub struct S;
diff --git a/src/test/rustdoc/src-links.rs b/src/test/rustdoc/src-links.rs
index 902a319a7b906..353ce10243e00 100644
--- a/src/test/rustdoc/src-links.rs
+++ b/src/test/rustdoc/src-links.rs
@@ -14,13 +14,11 @@ pub mod bar {
     // @has foo/bar/baz/index.html '//a/@href' '../../../src/foo/src-links.rs.html'
     pub mod baz {
         /// Dox
-        // @has foo/bar/baz/baz.v.html
         // @has foo/bar/baz/fn.baz.html '//a/@href' '../../../src/foo/src-links.rs.html'
         pub fn baz() { }
     }
 
     /// Dox
-    // @has foo/bar/Foobar.t.html
     // @has foo/bar/trait.Foobar.html '//a/@href' '../../src/foo/src-links.rs.html'
     pub trait Foobar { fn dummy(&self) { } }
 
diff --git a/src/test/rustdoc/stability.rs b/src/test/rustdoc/stability.rs
new file mode 100644
index 0000000000000..18a21603493c2
--- /dev/null
+++ b/src/test/rustdoc/stability.rs
@@ -0,0 +1,12 @@
+#![feature(staged_api)]
+
+#![unstable(feature = "test", issue = "0")]
+
+pub struct Unstable {
+    // @has stability/struct.Unstable.html \
+    //      '//div[@class="stability"]//div[@class="stab unstable"]' \
+    //      'This is a nightly-only experimental API'
+    // @count stability/struct.Unstable.html '//span[@class="stab unstable"]' 0
+    pub foo: u32,
+    pub bar: u32,
+}
diff --git a/src/test/rustdoc/structfields.rs b/src/test/rustdoc/structfields.rs
index 35cea8afe2146..235f0e852da2c 100644
--- a/src/test/rustdoc/structfields.rs
+++ b/src/test/rustdoc/structfields.rs
@@ -1,3 +1,5 @@
+// compile-flags:-Z unstable-options --generate-redirect-pages
+
 // @has structfields/Foo.t.html
 // @has - struct.Foo.html
 // @has structfields/struct.Foo.html
diff --git a/src/test/rustdoc/trait_alias.rs b/src/test/rustdoc/trait_alias.rs
new file mode 100644
index 0000000000000..98b8d879ac078
--- /dev/null
+++ b/src/test/rustdoc/trait_alias.rs
@@ -0,0 +1,21 @@
+#![feature(trait_alias)]
+
+#![crate_name = "foo"]
+
+use std::fmt::Debug;
+
+// @has foo/all.html '//a[@href="traitalias.CopyAlias.html"]' 'CopyAlias'
+// @has foo/all.html '//a[@href="traitalias.Alias2.html"]' 'Alias2'
+// @has foo/all.html '//a[@href="traitalias.Foo.html"]' 'Foo'
+
+// @has foo/index.html '//h2[@id="trait-aliases"]' 'Trait aliases'
+// @has foo/index.html '//a[@class="traitalias"]' 'CopyAlias'
+// @has foo/index.html '//a[@class="traitalias"]' 'Alias2'
+// @has foo/index.html '//a[@class="traitalias"]' 'Foo'
+
+// @has foo/traitalias.CopyAlias.html '//section[@id="main"]/pre' 'trait CopyAlias = Copy;'
+pub trait CopyAlias = Copy;
+// @has foo/traitalias.Alias2.html '//section[@id="main"]/pre' 'trait Alias2 = Copy + Debug;'
+pub trait Alias2 = Copy + Debug;
+// @has foo/traitalias.Foo.html '//section[@id="main"]/pre' 'trait Foo<T> = Into<T> + Debug;'
+pub trait Foo<T> = Into<T> + Debug;
diff --git a/src/test/rustdoc/use-attr.rs b/src/test/rustdoc/use-attr.rs
new file mode 100644
index 0000000000000..996b7bba62181
--- /dev/null
+++ b/src/test/rustdoc/use-attr.rs
@@ -0,0 +1,8 @@
+// edition:2018
+
+// ICE when rustdoc encountered a use statement of a non-macro attribute (see #58054)
+
+// @has use_attr/index.html
+// @has - '//code' 'pub use proc_macro_attribute'
+pub use proc_macro_attribute;
+use proc_macro_derive;
diff --git a/src/test/rustdoc/without-redirect.rs b/src/test/rustdoc/without-redirect.rs
new file mode 100644
index 0000000000000..a076f8a3c5ec7
--- /dev/null
+++ b/src/test/rustdoc/without-redirect.rs
@@ -0,0 +1,13 @@
+#![crate_name = "foo"]
+
+// @has foo/macro.bar.html
+// @has foo/macro.bar!.html
+// @!has foo/bar.m.html
+#[macro_export]
+macro_rules! bar {
+    () => {}
+}
+
+// @has foo/struct.Bar.html
+// @!has foo/Bar.t.html
+pub struct Bar;
diff --git a/src/test/rustdoc/wrapping.rs b/src/test/rustdoc/wrapping.rs
new file mode 100644
index 0000000000000..8d8221bcdf293
--- /dev/null
+++ b/src/test/rustdoc/wrapping.rs
@@ -0,0 +1,5 @@
+use std::fmt::Debug;
+
+// @has 'wrapping/fn.foo.html' '//pre[@class="rust fn"]' 'pub fn foo() -> impl Debug'
+// @count - '//pre[@class="rust fn"]/br' 0
+pub fn foo() -> impl Debug {}
diff --git a/src/test/ui-fulldeps/auxiliary/lint_for_crate.rs b/src/test/ui-fulldeps/auxiliary/lint_for_crate.rs
index 23bda04f9b328..82aa28b26b648 100644
--- a/src/test/ui-fulldeps/auxiliary/lint_for_crate.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint_for_crate.rs
@@ -17,6 +17,10 @@ declare_lint!(CRATE_NOT_OKAY, Warn, "crate not marked with #![crate_okay]");
 struct Pass;
 
 impl LintPass for Pass {
+    fn name(&self) -> &'static str {
+        "Pass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(CRATE_NOT_OKAY)
     }
diff --git a/src/test/ui-fulldeps/auxiliary/lint_group_plugin_test.rs b/src/test/ui-fulldeps/auxiliary/lint_group_plugin_test.rs
index bca1d7a72b4ab..16630e2b31285 100644
--- a/src/test/ui-fulldeps/auxiliary/lint_group_plugin_test.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint_group_plugin_test.rs
@@ -19,6 +19,10 @@ declare_lint!(PLEASE_LINT, Warn, "Warn about items named 'pleaselintme'");
 struct Pass;
 
 impl LintPass for Pass {
+    fn name(&self) -> &'static str {
+        "Pass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TEST_LINT, PLEASE_LINT)
     }
diff --git a/src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs b/src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs
index 9b0127ea5c006..4e45189b42427 100644
--- a/src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs
@@ -19,6 +19,10 @@ declare_lint!(TEST_LINT, Warn, "Warn about items named 'lintme'");
 struct Pass;
 
 impl LintPass for Pass {
+    fn name(&self) -> &'static str {
+        "Pass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TEST_LINT)
     }
diff --git a/src/test/ui-fulldeps/auxiliary/lint_tool_test.rs b/src/test/ui-fulldeps/auxiliary/lint_tool_test.rs
index 5c9569ddc6575..1a9bd9e66dbac 100644
--- a/src/test/ui-fulldeps/auxiliary/lint_tool_test.rs
+++ b/src/test/ui-fulldeps/auxiliary/lint_tool_test.rs
@@ -18,6 +18,10 @@ declare_tool_lint!(pub clippy::TEST_GROUP, Warn, "Warn about other stuff");
 struct Pass;
 
 impl LintPass for Pass {
+    fn name(&self) -> &'static str {
+        "Pass"
+    }
+
     fn get_lints(&self) -> LintArray {
         lint_array!(TEST_LINT, TEST_GROUP)
     }
diff --git a/src/test/ui-fulldeps/auxiliary/macro_crate_test.rs b/src/test/ui-fulldeps/auxiliary/macro_crate_test.rs
deleted file mode 100644
index a364aa0422deb..0000000000000
--- a/src/test/ui-fulldeps/auxiliary/macro_crate_test.rs
+++ /dev/null
@@ -1,149 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar, quote, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_pos;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use syntax::ast::{self, Item, MetaItem, ItemKind};
-use syntax::ext::base::*;
-use syntax::parse;
-use syntax::ptr::P;
-use syntax::symbol::Symbol;
-use syntax::tokenstream::TokenTree;
-use syntax_pos::Span;
-use rustc_plugin::Registry;
-
-#[macro_export]
-macro_rules! exported_macro { () => (2) }
-macro_rules! unexported_macro { () => (3) }
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("make_a_1", expand_make_a_1);
-    reg.register_macro("identity", expand_identity);
-    reg.register_syntax_extension(
-        Symbol::intern("into_multi_foo"),
-        MultiModifier(Box::new(expand_into_foo_multi)));
-    reg.register_syntax_extension(
-        Symbol::intern("noop_attribute"),
-        MultiModifier(Box::new(expand_noop_attribute)));
-    reg.register_syntax_extension(
-        Symbol::intern("duplicate"),
-        MultiDecorator(Box::new(expand_duplicate)));
-}
-
-fn expand_make_a_1(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree])
-                   -> Box<MacResult+'static> {
-    if !tts.is_empty() {
-        cx.span_fatal(sp, "make_a_1 takes no arguments");
-    }
-    MacEager::expr(quote_expr!(cx, 1))
-}
-
-// See Issue #15750
-fn expand_identity(cx: &mut ExtCtxt, _span: Span, tts: &[TokenTree])
-                   -> Box<MacResult+'static> {
-    // Parse an expression and emit it unchanged.
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), tts.to_vec());
-    let expr = parser.parse_expr().unwrap();
-    MacEager::expr(quote_expr!(&mut *cx, $expr))
-}
-
-fn expand_into_foo_multi(cx: &mut ExtCtxt,
-                         _sp: Span,
-                         _attr: &MetaItem,
-                         it: Annotatable) -> Annotatable {
-    match it {
-        Annotatable::Item(it) => {
-            Annotatable::Item(P(Item {
-                attrs: it.attrs.clone(),
-                ..(*quote_item!(cx, enum Foo2 { Bar2, Baz2 }).unwrap()).clone()
-            }))
-        }
-        Annotatable::ImplItem(_) => {
-            quote_item!(cx, impl X { fn foo(&self) -> i32 { 42 } }).unwrap().and_then(|i| {
-                match i.node {
-                    ItemKind::Impl(.., mut items) => {
-                        Annotatable::ImplItem(P(items.pop().expect("impl method not found")))
-                    }
-                    _ => unreachable!("impl parsed to something other than impl")
-                }
-            })
-        }
-        Annotatable::TraitItem(_) => {
-            quote_item!(cx, trait X { fn foo(&self) -> i32 { 0 } }).unwrap().and_then(|i| {
-                match i.node {
-                    ItemKind::Trait(.., mut items) => {
-                        Annotatable::TraitItem(P(items.pop().expect("trait method not found")))
-                    }
-                    _ => unreachable!("trait parsed to something other than trait")
-                }
-            })
-        }
-        // covered in proc_macro/macros-in-extern.rs
-        Annotatable::ForeignItem(_) => unimplemented!(),
-        // covered in proc_macro/attr-stmt-expr.rs
-        Annotatable::Stmt(_) | Annotatable::Expr(_) => panic!("expected item")
-    }
-}
-
-fn expand_noop_attribute(_cx: &mut ExtCtxt,
-                         _sp: Span,
-                         _attr: &MetaItem,
-                         it: Annotatable) -> Annotatable {
-    it
-}
-
-// Create a duplicate of the annotatable, based on the MetaItem
-fn expand_duplicate(cx: &mut ExtCtxt,
-                    _sp: Span,
-                    mi: &MetaItem,
-                    it: &Annotatable,
-                    push: &mut FnMut(Annotatable))
-{
-    let copy_name = match mi.node {
-        ast::MetaItemKind::List(ref xs) => {
-            if let Some(word) = xs[0].word() {
-                word.ident.segments.last().unwrap().ident
-            } else {
-                cx.span_err(mi.span, "Expected word");
-                return;
-            }
-        }
-        _ => {
-            cx.span_err(mi.span, "Expected list");
-            return;
-        }
-    };
-
-    // Duplicate the item but replace its ident by the MetaItem
-    match it.clone() {
-        Annotatable::Item(it) => {
-            let mut new_it = (*it).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::Item(P(new_it)));
-        }
-        Annotatable::ImplItem(it) => {
-            let mut new_it = (*it).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::ImplItem(P(new_it)));
-        }
-        Annotatable::TraitItem(tt) => {
-            let mut new_it = (*tt).clone();
-            new_it.attrs.clear();
-            new_it.ident = copy_name;
-            push(Annotatable::TraitItem(P(new_it)));
-        }
-        // covered in proc_macro/macros-in-extern.rs
-        Annotatable::ForeignItem(_) => unimplemented!(),
-        // covered in proc_macro/attr-stmt-expr.rs
-        Annotatable::Stmt(_) | Annotatable::Expr(_) => panic!("expected item")
-    }
-}
-
-pub fn foo() {}
diff --git a/src/test/ui-fulldeps/gated-plugin.rs b/src/test/ui-fulldeps/gated-plugin.rs
index 3a138d9af03ca..a647585e621fe 100644
--- a/src/test/ui-fulldeps/gated-plugin.rs
+++ b/src/test/ui-fulldeps/gated-plugin.rs
@@ -1,6 +1,6 @@
-// aux-build:macro_crate_test.rs
+// aux-build:attr_plugin_test.rs
 
-#![plugin(macro_crate_test)]
+#![plugin(attr_plugin_test)]
 //~^ ERROR compiler plugins are experimental and possibly buggy
 
 fn main() {}
diff --git a/src/test/ui-fulldeps/gated-plugin.stderr b/src/test/ui-fulldeps/gated-plugin.stderr
index a72a45833d011..37c2b4432470d 100644
--- a/src/test/ui-fulldeps/gated-plugin.stderr
+++ b/src/test/ui-fulldeps/gated-plugin.stderr
@@ -1,7 +1,7 @@
 error[E0658]: compiler plugins are experimental and possibly buggy (see issue #29597)
   --> $DIR/gated-plugin.rs:3:1
    |
-LL | #![plugin(macro_crate_test)]
+LL | #![plugin(attr_plugin_test)]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(plugin)] to the crate attributes to enable
diff --git a/src/test/ui-fulldeps/gated-quote.rs b/src/test/ui-fulldeps/gated-quote.rs
deleted file mode 100644
index 86848e3156fbd..0000000000000
--- a/src/test/ui-fulldeps/gated-quote.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-// Test that `quote`-related macro are gated by `quote` feature gate.
-
-// (To sanity-check the code, uncomment this.)
-// #![feature(quote)]
-
-// FIXME the error message that is current emitted seems pretty bad.
-
-// gate-test-quote
-
-#![feature(rustc_private)]
-#![allow(dead_code, unused_imports, unused_variables)]
-
-#[macro_use]
-extern crate syntax;
-
-use syntax::ast;
-use syntax::parse;
-
-struct ParseSess;
-
-impl ParseSess {
-    fn cfg(&self) -> ast::CrateConfig { loop { } }
-    fn parse_sess<'a>(&'a self) -> &'a parse::ParseSess { loop { } }
-    fn call_site(&self) -> () { loop { } }
-    fn ident_of(&self, st: &str) -> ast::Ident { loop { } }
-    fn name_of(&self, st: &str) -> ast::Name { loop { } }
-}
-
-pub fn main() {
-    let ecx = &ParseSess;
-    let x = quote_tokens!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_tokens!` in this scope
-    let x = quote_expr!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_expr!` in this scope
-    let x = quote_ty!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_ty!` in this scope
-    let x = quote_method!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_method!` in this scope
-    let x = quote_item!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_item!` in this scope
-    let x = quote_pat!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_pat!` in this scope
-    let x = quote_arm!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_arm!` in this scope
-    let x = quote_stmt!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_stmt!` in this scope
-    let x = quote_attr!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_attr!` in this scope
-    let x = quote_arg!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_arg!` in this scope
-    let x = quote_block!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_block!` in this scope
-    let x = quote_meta_item!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_meta_item!` in this scope
-    let x = quote_path!(ecx, 3);
-    //~^ ERROR cannot find macro `quote_path!` in this scope
-}
diff --git a/src/test/ui-fulldeps/gated-quote.stderr b/src/test/ui-fulldeps/gated-quote.stderr
deleted file mode 100644
index 897e97b7eb1ee..0000000000000
--- a/src/test/ui-fulldeps/gated-quote.stderr
+++ /dev/null
@@ -1,80 +0,0 @@
-error: cannot find macro `quote_path!` in this scope
-  --> $DIR/gated-quote.rs:55:13
-   |
-LL |     let x = quote_path!(ecx, 3);
-   |             ^^^^^^^^^^
-
-error: cannot find macro `quote_meta_item!` in this scope
-  --> $DIR/gated-quote.rs:53:13
-   |
-LL |     let x = quote_meta_item!(ecx, 3);
-   |             ^^^^^^^^^^^^^^^
-
-error: cannot find macro `quote_block!` in this scope
-  --> $DIR/gated-quote.rs:51:13
-   |
-LL |     let x = quote_block!(ecx, 3);
-   |             ^^^^^^^^^^^
-
-error: cannot find macro `quote_arg!` in this scope
-  --> $DIR/gated-quote.rs:49:13
-   |
-LL |     let x = quote_arg!(ecx, 3);
-   |             ^^^^^^^^^
-
-error: cannot find macro `quote_attr!` in this scope
-  --> $DIR/gated-quote.rs:47:13
-   |
-LL |     let x = quote_attr!(ecx, 3);
-   |             ^^^^^^^^^^
-
-error: cannot find macro `quote_stmt!` in this scope
-  --> $DIR/gated-quote.rs:45:13
-   |
-LL |     let x = quote_stmt!(ecx, 3);
-   |             ^^^^^^^^^^
-
-error: cannot find macro `quote_arm!` in this scope
-  --> $DIR/gated-quote.rs:43:13
-   |
-LL |     let x = quote_arm!(ecx, 3);
-   |             ^^^^^^^^^
-
-error: cannot find macro `quote_pat!` in this scope
-  --> $DIR/gated-quote.rs:41:13
-   |
-LL |     let x = quote_pat!(ecx, 3);
-   |             ^^^^^^^^^
-
-error: cannot find macro `quote_item!` in this scope
-  --> $DIR/gated-quote.rs:39:13
-   |
-LL |     let x = quote_item!(ecx, 3);
-   |             ^^^^^^^^^^
-
-error: cannot find macro `quote_method!` in this scope
-  --> $DIR/gated-quote.rs:37:13
-   |
-LL |     let x = quote_method!(ecx, 3);
-   |             ^^^^^^^^^^^^
-
-error: cannot find macro `quote_ty!` in this scope
-  --> $DIR/gated-quote.rs:35:13
-   |
-LL |     let x = quote_ty!(ecx, 3);
-   |             ^^^^^^^^
-
-error: cannot find macro `quote_expr!` in this scope
-  --> $DIR/gated-quote.rs:33:13
-   |
-LL |     let x = quote_expr!(ecx, 3);
-   |             ^^^^^^^^^^
-
-error: cannot find macro `quote_tokens!` in this scope
-  --> $DIR/gated-quote.rs:31:13
-   |
-LL |     let x = quote_tokens!(ecx, 3);
-   |             ^^^^^^^^^^^^
-
-error: aborting due to 13 previous errors
-
diff --git a/src/test/ui-fulldeps/issue-48941.rs b/src/test/ui-fulldeps/issue-48941.rs
deleted file mode 100644
index 8c4c2445670b8..0000000000000
--- a/src/test/ui-fulldeps/issue-48941.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// This is a regression test against an ICE that used to occur
-// on malformed attributes for a custom MultiModifier.
-
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-
-#![feature(plugin)]
-#![plugin(macro_crate_test)]
-
-#[noop_attribute("hi", rank = a)] //~ ERROR expected unsuffixed literal or identifier, found a
-fn knight() { }
-
-#[noop_attribute("/user", data= = "<user")] //~ ERROR literal or identifier
-fn nite() { }
-
-fn main() {}
diff --git a/src/test/ui-fulldeps/issue-48941.stderr b/src/test/ui-fulldeps/issue-48941.stderr
deleted file mode 100644
index 6ccea4330493d..0000000000000
--- a/src/test/ui-fulldeps/issue-48941.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: expected unsuffixed literal or identifier, found a
-  --> $DIR/issue-48941.rs:10:24
-   |
-LL | #[noop_attribute("hi", rank = a)] //~ ERROR expected unsuffixed literal or identifier, found a
-   |                        ^^^^
-
-error: expected unsuffixed literal or identifier, found =
-  --> $DIR/issue-48941.rs:13:27
-   |
-LL | #[noop_attribute("/user", data= = "<user")] //~ ERROR literal or identifier
-   |                           ^^^^
-
-error: aborting due to 2 previous errors
-
diff --git a/src/test/ui-fulldeps/macro-crate-doesnt-resolve.rs b/src/test/ui-fulldeps/macro-crate-doesnt-resolve.rs
deleted file mode 100644
index 1e8de1282a082..0000000000000
--- a/src/test/ui-fulldeps/macro-crate-doesnt-resolve.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-// aux-build:macro_crate_test.rs
-
-#[macro_use] #[no_link]
-extern crate macro_crate_test;
-
-fn main() {
-    macro_crate_test::foo(); //~ ERROR cannot find function `foo` in module `macro_crate_test`
-}
diff --git a/src/test/ui-fulldeps/macro-crate-doesnt-resolve.stderr b/src/test/ui-fulldeps/macro-crate-doesnt-resolve.stderr
deleted file mode 100644
index 510cedb0c2029..0000000000000
--- a/src/test/ui-fulldeps/macro-crate-doesnt-resolve.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0425]: cannot find function `foo` in module `macro_crate_test`
-  --> $DIR/macro-crate-doesnt-resolve.rs:7:23
-   |
-LL |     macro_crate_test::foo(); //~ ERROR cannot find function `foo` in module `macro_crate_test`
-   |                       ^^^ not found in `macro_crate_test`
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui-fulldeps/macro-crate-unexported-macro.rs b/src/test/ui-fulldeps/macro-crate-unexported-macro.rs
deleted file mode 100644
index 8cf0cc4e4f385..0000000000000
--- a/src/test/ui-fulldeps/macro-crate-unexported-macro.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-// aux-build:macro_crate_test.rs
-
-#[macro_use] #[no_link]
-extern crate macro_crate_test;
-
-fn main() {
-    unexported_macro!();
-    //~^ ERROR cannot find macro `unexported_macro!` in this scope
-}
diff --git a/src/test/ui-fulldeps/macro-crate-unexported-macro.stderr b/src/test/ui-fulldeps/macro-crate-unexported-macro.stderr
deleted file mode 100644
index 0d1b4b64fc5ee..0000000000000
--- a/src/test/ui-fulldeps/macro-crate-unexported-macro.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: cannot find macro `unexported_macro!` in this scope
-  --> $DIR/macro-crate-unexported-macro.rs:7:5
-   |
-LL |     unexported_macro!();
-   |     ^^^^^^^^^^^^^^^^ help: you could try the macro: `exported_macro`
-
-error: aborting due to previous error
-
diff --git a/src/test/ui-fulldeps/plugin-as-extern-crate.rs b/src/test/ui-fulldeps/plugin-as-extern-crate.rs
index f192694dc7318..37ac8dfa39101 100644
--- a/src/test/ui-fulldeps/plugin-as-extern-crate.rs
+++ b/src/test/ui-fulldeps/plugin-as-extern-crate.rs
@@ -1,12 +1,12 @@
-// aux-build:macro_crate_test.rs
+// aux-build:attr_plugin_test.rs
 // ignore-cross-compile
 //
-// macro_crate_test will not compile on a cross-compiled target because
+// attr_plugin_test will not compile on a cross-compiled target because
 // libsyntax is not compiled for it.
 
 #![deny(plugin_as_library)]
 #![allow(unused_extern_crates)]
 
-extern crate macro_crate_test; //~ ERROR compiler plugin used as an ordinary library
+extern crate attr_plugin_test; //~ ERROR compiler plugin used as an ordinary library
 
 fn main() { }
diff --git a/src/test/ui-fulldeps/plugin-as-extern-crate.stderr b/src/test/ui-fulldeps/plugin-as-extern-crate.stderr
index f0406d5181aa1..4a5a53980eb8a 100644
--- a/src/test/ui-fulldeps/plugin-as-extern-crate.stderr
+++ b/src/test/ui-fulldeps/plugin-as-extern-crate.stderr
@@ -1,7 +1,7 @@
 error: compiler plugin used as an ordinary library
   --> $DIR/plugin-as-extern-crate.rs:10:1
    |
-LL | extern crate macro_crate_test; //~ ERROR compiler plugin used as an ordinary library
+LL | extern crate attr_plugin_test; //~ ERROR compiler plugin used as an ordinary library
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 note: lint level defined here
diff --git a/src/test/ui-fulldeps/plugin-plus-extern-crate.rs b/src/test/ui-fulldeps/plugin-plus-extern-crate.rs
deleted file mode 100644
index db13954f8eda9..0000000000000
--- a/src/test/ui-fulldeps/plugin-plus-extern-crate.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-// aux-build:macro_crate_test.rs
-// ignore-stage1
-// ignore-cross-compile
-//
-// macro_crate_test will not compile on a cross-compiled target because
-// libsyntax is not compiled for it.
-
-#![deny(plugin_as_library)]
-#![feature(plugin)]
-#![plugin(macro_crate_test)]
-
-extern crate macro_crate_test; //~ ERROR compiler plugin used as an ordinary library
-
-fn main() {
-    assert_eq!(1, make_a_1!());
-    macro_crate_test::foo();
-}
diff --git a/src/test/ui-fulldeps/plugin-plus-extern-crate.stderr b/src/test/ui-fulldeps/plugin-plus-extern-crate.stderr
deleted file mode 100644
index 284d76b613263..0000000000000
--- a/src/test/ui-fulldeps/plugin-plus-extern-crate.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: compiler plugin used as an ordinary library
-  --> $DIR/plugin-plus-extern-crate.rs:12:1
-   |
-LL | extern crate macro_crate_test; //~ ERROR compiler plugin used as an ordinary library
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: lint level defined here
-  --> $DIR/plugin-plus-extern-crate.rs:8:9
-   |
-LL | #![deny(plugin_as_library)]
-   |         ^^^^^^^^^^^^^^^^^
-
-error: aborting due to previous error
-
diff --git a/src/test/ui-fulldeps/qquote.rs b/src/test/ui-fulldeps/qquote.rs
deleted file mode 100644
index 99e365d21ff94..0000000000000
--- a/src/test/ui-fulldeps/qquote.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-// ignore-cross-compile
-
-#![feature(quote, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_pos;
-
-use syntax::ast;
-use syntax::source_map::FilePathMapping;
-use syntax::print::pprust;
-use syntax::symbol::Symbol;
-use syntax_pos::DUMMY_SP;
-
-fn main() {
-    let ps = syntax::parse::ParseSess::new(FilePathMapping::empty());
-    let mut resolver = syntax::ext::base::DummyResolver;
-    let mut cx = syntax::ext::base::ExtCtxt::new(
-        &ps,
-        syntax::ext::expand::ExpansionConfig::default("qquote".to_string()),
-        &mut resolver);
-    let cx = &mut cx;
-
-    assert_eq!(pprust::expr_to_string(&*quote_expr!(&cx, 23)), "23");
-
-    let expr = quote_expr!(&cx, 2 - $abcd + 7); //~ ERROR cannot find value `abcd` in this scope
-    assert_eq!(pprust::expr_to_string(&*expr), "2 - $abcd + 7");
-}
diff --git a/src/test/ui-fulldeps/qquote.stderr b/src/test/ui-fulldeps/qquote.stderr
deleted file mode 100644
index a51318b0edc98..0000000000000
--- a/src/test/ui-fulldeps/qquote.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0425]: cannot find value `abcd` in this scope
-  --> $DIR/qquote.rs:25:38
-   |
-LL |     let expr = quote_expr!(&cx, 2 - $abcd + 7); //~ ERROR cannot find value `abcd` in this scope
-   |                                      ^^^^ not found in this scope
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/anonymous-higher-ranked-lifetime.rs b/src/test/ui/anonymous-higher-ranked-lifetime.rs
index 55b1667da50b1..2e2a124db9a5d 100644
--- a/src/test/ui/anonymous-higher-ranked-lifetime.rs
+++ b/src/test/ui/anonymous-higher-ranked-lifetime.rs
@@ -1,15 +1,26 @@
 fn main() {
     f1(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     f2(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     f3(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     f4(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     f5(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     g1(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     g2(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     g3(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     g4(|_: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     h1(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
     h2(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
 }
 
 // Basic
diff --git a/src/test/ui/anonymous-higher-ranked-lifetime.stderr b/src/test/ui/anonymous-higher-ranked-lifetime.stderr
index d2c722e32b210..378f352cb9228 100644
--- a/src/test/ui/anonymous-higher-ranked-lifetime.stderr
+++ b/src/test/ui/anonymous-higher-ranked-lifetime.stderr
@@ -7,13 +7,27 @@ LL |     f1(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r, 's> fn(&'r (), &'s ()) -> _`
    |
 note: required by `f1`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:16:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:27:1
    |
 LL | fn f1<F>(_: F) where F: Fn(&(), &()) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:3:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:2:5
+   |
+LL |     f1(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), &()) -> _`
+   |
+note: required by `f1`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:27:1
+   |
+LL | fn f1<F>(_: F) where F: Fn(&(), &()) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:4:5
    |
 LL |     f2(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -21,7 +35,7 @@ LL |     f2(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'a, 'r> fn(&'a (), &'r ()) -> _`
    |
 note: required by `f2`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:17:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:28:1
    |
 LL | fn f2<F>(_: F) where F: for<'a> Fn(&'a (), &()) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -29,19 +43,47 @@ LL | fn f2<F>(_: F) where F: for<'a> Fn(&'a (), &()) {}
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:4:5
    |
+LL |     f2(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&'a (), &()) -> _`
+   |
+note: required by `f2`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:28:1
+   |
+LL | fn f2<F>(_: F) where F: for<'a> Fn(&'a (), &()) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:6:5
+   |
 LL |     f3(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
    |     |
    |     expected signature of `for<'r> fn(&(), &'r ()) -> _`
    |
 note: required by `f3`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:18:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:29:1
    |
 LL | fn f3<'a, F>(_: F) where F: Fn(&'a (), &()) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:5:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:6:5
+   |
+LL |     f3(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), &()) -> _`
+   |
+note: required by `f3`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:29:1
+   |
+LL | fn f3<'a, F>(_: F) where F: Fn(&'a (), &()) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:8:5
    |
 LL |     f4(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -49,13 +91,27 @@ LL |     f4(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'s, 'r> fn(&'s (), &'r ()) -> _`
    |
 note: required by `f4`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:19:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:30:1
    |
 LL | fn f4<F>(_: F) where F: for<'r> Fn(&(), &'r ()) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:6:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:8:5
+   |
+LL |     f4(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), &'r ()) -> _`
+   |
+note: required by `f4`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:30:1
+   |
+LL | fn f4<F>(_: F) where F: for<'r> Fn(&(), &'r ()) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:10:5
    |
 LL |     f5(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -63,13 +119,27 @@ LL |     f5(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r> fn(&'r (), &'r ()) -> _`
    |
 note: required by `f5`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:20:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:31:1
    |
 LL | fn f5<F>(_: F) where F: for<'r> Fn(&'r (), &'r ()) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:7:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:10:5
+   |
+LL |     f5(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&'r (), &'r ()) -> _`
+   |
+note: required by `f5`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:31:1
+   |
+LL | fn f5<F>(_: F) where F: for<'r> Fn(&'r (), &'r ()) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:12:5
    |
 LL |     g1(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -77,13 +147,27 @@ LL |     g1(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r> fn(&'r (), std::boxed::Box<(dyn for<'s> std::ops::Fn(&'s ()) + 'static)>) -> _`
    |
 note: required by `g1`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:23:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:34:1
    |
 LL | fn g1<F>(_: F) where F: Fn(&(), Box<Fn(&())>) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:8:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:12:5
+   |
+LL |     g1(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r ()) + 'static)>) -> _`
+   |
+note: required by `g1`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:34:1
+   |
+LL | fn g1<F>(_: F) where F: Fn(&(), Box<Fn(&())>) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:14:5
    |
 LL |     g2(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -91,13 +175,27 @@ LL |     g2(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r> fn(&'r (), for<'s> fn(&'s ())) -> _`
    |
 note: required by `g2`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:24:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:35:1
    |
 LL | fn g2<F>(_: F) where F: Fn(&(), fn(&())) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:9:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:14:5
+   |
+LL |     g2(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), for<'r> fn(&'r ())) -> _`
+   |
+note: required by `g2`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:35:1
+   |
+LL | fn g2<F>(_: F) where F: Fn(&(), fn(&())) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:16:5
    |
 LL |     g3(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -105,13 +203,27 @@ LL |     g3(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'s> fn(&'s (), std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r ()) + 'static)>) -> _`
    |
 note: required by `g3`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:25:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:36:1
    |
 LL | fn g3<F>(_: F) where F: for<'s> Fn(&'s (), Box<Fn(&())>) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:10:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:16:5
+   |
+LL |     g3(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&'s (), std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r ()) + 'static)>) -> _`
+   |
+note: required by `g3`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:36:1
+   |
+LL | fn g3<F>(_: F) where F: for<'s> Fn(&'s (), Box<Fn(&())>) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:18:5
    |
 LL |     g4(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ -------------- found signature of `fn((), ()) -> _`
@@ -119,13 +231,27 @@ LL |     g4(|_: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'s> fn(&'s (), for<'r> fn(&'r ())) -> _`
    |
 note: required by `g4`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:26:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:37:1
+   |
+LL | fn g4<F>(_: F) where F: Fn(&(), for<'r> fn(&'r ())) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:18:5
+   |
+LL |     g4(|_: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ -------------- found signature of `fn((), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), for<'r> fn(&'r ())) -> _`
+   |
+note: required by `g4`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:37:1
    |
 LL | fn g4<F>(_: F) where F: Fn(&(), for<'r> fn(&'r ())) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:11:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:20:5
    |
 LL |     h1(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ ---------------------------- found signature of `fn((), (), (), ()) -> _`
@@ -133,13 +259,27 @@ LL |     h1(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r, 's> fn(&'r (), std::boxed::Box<(dyn for<'t0> std::ops::Fn(&'t0 ()) + 'static)>, &'s (), for<'t0, 't1> fn(&'t0 (), &'t1 ())) -> _`
    |
 note: required by `h1`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:29:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:40:1
    |
 LL | fn h1<F>(_: F) where F: Fn(&(), Box<Fn(&())>, &(), fn(&(), &())) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0631]: type mismatch in closure arguments
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:12:5
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:20:5
+   |
+LL |     h1(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ ---------------------------- found signature of `fn((), (), (), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r ()) + 'static)>, &(), for<'r, 's> fn(&'r (), &'s ())) -> _`
+   |
+note: required by `h1`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:40:1
+   |
+LL | fn h1<F>(_: F) where F: Fn(&(), Box<Fn(&())>, &(), fn(&(), &())) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:22:5
    |
 LL |     h2(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
    |     ^^ ---------------------------- found signature of `fn((), (), (), ()) -> _`
@@ -147,11 +287,25 @@ LL |     h2(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
    |     expected signature of `for<'r, 't0> fn(&'r (), std::boxed::Box<(dyn for<'s> std::ops::Fn(&'s ()) + 'static)>, &'t0 (), for<'s, 't1> fn(&'s (), &'t1 ())) -> _`
    |
 note: required by `h2`
-  --> $DIR/anonymous-higher-ranked-lifetime.rs:30:1
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:41:1
+   |
+LL | fn h2<F>(_: F) where F: for<'t0> Fn(&(), Box<Fn(&())>, &'t0 (), fn(&(), &())) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:22:5
+   |
+LL |     h2(|_: (), _: (), _: (), _: ()| {}); //~ ERROR type mismatch
+   |     ^^ ---------------------------- found signature of `fn((), (), (), ()) -> _`
+   |     |
+   |     expected signature of `fn(&(), std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r ()) + 'static)>, &'t0 (), for<'r, 's> fn(&'r (), &'s ())) -> _`
+   |
+note: required by `h2`
+  --> $DIR/anonymous-higher-ranked-lifetime.rs:41:1
    |
 LL | fn h2<F>(_: F) where F: for<'t0> Fn(&(), Box<Fn(&())>, &'t0 (), fn(&(), &())) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 11 previous errors
+error: aborting due to 22 previous errors
 
 For more information about this error, try `rustc --explain E0631`.
diff --git a/src/test/ui/associated-types/associated-types-coherence-failure.rs b/src/test/ui/associated-types/associated-types-coherence-failure.rs
index fe1201ea06f18..c33f2ac96ba62 100644
--- a/src/test/ui/associated-types/associated-types-coherence-failure.rs
+++ b/src/test/ui/associated-types/associated-types-coherence-failure.rs
@@ -41,7 +41,7 @@ impl ToOwned for u8 {
 pub trait ToOwned {
     type Owned;
 
-    /// Create owned data from borrowed data, usually by copying.
+    /// Creates owned data from borrowed data, usually by copying.
     fn to_owned(&self) -> Self::Owned;
 }
 
diff --git a/src/test/ui/associated-types/associated-types-eq-hr.rs b/src/test/ui/associated-types/associated-types-eq-hr.rs
index 20fa1e7a48db1..e6afa3f71c2f0 100644
--- a/src/test/ui/associated-types/associated-types-eq-hr.rs
+++ b/src/test/ui/associated-types/associated-types-eq-hr.rs
@@ -89,12 +89,14 @@ pub fn call_bar() {
 
 pub fn call_tuple_one() {
     tuple_one::<Tuple>();
-    //~^ ERROR not general enough
+    //~^ ERROR not satisfied
+    //~| ERROR type mismatch
 }
 
 pub fn call_tuple_two() {
     tuple_two::<Tuple>();
-    //~^ ERROR not general enough
+    //~^ ERROR not satisfied
+    //~| ERROR type mismatch
 }
 
 pub fn call_tuple_three() {
@@ -103,7 +105,7 @@ pub fn call_tuple_three() {
 
 pub fn call_tuple_four() {
     tuple_four::<Tuple>();
-    //~^ ERROR not general enough
+    //~^ ERROR not satisfied
 }
 
 fn main() { }
diff --git a/src/test/ui/associated-types/associated-types-eq-hr.stderr b/src/test/ui/associated-types/associated-types-eq-hr.stderr
index d3eaa894b5043..3721b69898876 100644
--- a/src/test/ui/associated-types/associated-types-eq-hr.stderr
+++ b/src/test/ui/associated-types/associated-types-eq-hr.stderr
@@ -34,36 +34,93 @@ LL | |     // ok for UintStruct, but not IntStruct
 LL | | }
    | |_^
 
-error: implementation of `TheTrait` is not general enough
+error[E0277]: the trait bound `for<'x, 'y> Tuple: TheTrait<(&'x isize, &'y isize)>` is not satisfied
   --> $DIR/associated-types-eq-hr.rs:91:5
    |
 LL |     tuple_one::<Tuple>();
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^ the trait `for<'x, 'y> TheTrait<(&'x isize, &'y isize)>` is not implemented for `Tuple`
    |
-   = note: Due to a where-clause on `tuple_one`,
-   = note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>` for any two lifetimes `'0` and `'1`
-   = note: but `Tuple` only implements `TheTrait<(&'2 isize, &'2 isize)>` for some lifetime `'2`
+   = help: the following implementations were found:
+             <Tuple as TheTrait<(&'a isize, &'a isize)>>
+note: required by `tuple_one`
+  --> $DIR/associated-types-eq-hr.rs:56:1
+   |
+LL | / fn tuple_one<T>()
+LL | |     where T : for<'x,'y> TheTrait<(&'x isize, &'y isize), A = &'x isize>
+LL | | {
+LL | |     // not ok for tuple, two lifetimes and we pick first
+LL | | }
+   | |_^
 
-error: implementation of `TheTrait` is not general enough
-  --> $DIR/associated-types-eq-hr.rs:96:5
+error[E0271]: type mismatch resolving `for<'x, 'y> <Tuple as TheTrait<(&'x isize, &'y isize)>>::A == &'x isize`
+  --> $DIR/associated-types-eq-hr.rs:91:5
+   |
+LL |     tuple_one::<Tuple>();
+   |     ^^^^^^^^^^^^^^^^^^ expected bound lifetime parameter 'x, found concrete lifetime
+   |
+note: required by `tuple_one`
+  --> $DIR/associated-types-eq-hr.rs:56:1
+   |
+LL | / fn tuple_one<T>()
+LL | |     where T : for<'x,'y> TheTrait<(&'x isize, &'y isize), A = &'x isize>
+LL | | {
+LL | |     // not ok for tuple, two lifetimes and we pick first
+LL | | }
+   | |_^
+
+error[E0277]: the trait bound `for<'x, 'y> Tuple: TheTrait<(&'x isize, &'y isize)>` is not satisfied
+  --> $DIR/associated-types-eq-hr.rs:97:5
    |
 LL |     tuple_two::<Tuple>();
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^ the trait `for<'x, 'y> TheTrait<(&'x isize, &'y isize)>` is not implemented for `Tuple`
+   |
+   = help: the following implementations were found:
+             <Tuple as TheTrait<(&'a isize, &'a isize)>>
+note: required by `tuple_two`
+  --> $DIR/associated-types-eq-hr.rs:62:1
    |
-   = note: Due to a where-clause on `tuple_two`,
-   = note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>` for any two lifetimes `'0` and `'1`
-   = note: but `Tuple` only implements `TheTrait<(&'2 isize, &'2 isize)>` for some lifetime `'2`
+LL | / fn tuple_two<T>()
+LL | |     where T : for<'x,'y> TheTrait<(&'x isize, &'y isize), A = &'y isize>
+LL | | {
+LL | |     // not ok for tuple, two lifetimes and we pick second
+LL | | }
+   | |_^
+
+error[E0271]: type mismatch resolving `for<'x, 'y> <Tuple as TheTrait<(&'x isize, &'y isize)>>::A == &'y isize`
+  --> $DIR/associated-types-eq-hr.rs:97:5
+   |
+LL |     tuple_two::<Tuple>();
+   |     ^^^^^^^^^^^^^^^^^^ expected bound lifetime parameter 'x, found concrete lifetime
+   |
+note: required by `tuple_two`
+  --> $DIR/associated-types-eq-hr.rs:62:1
+   |
+LL | / fn tuple_two<T>()
+LL | |     where T : for<'x,'y> TheTrait<(&'x isize, &'y isize), A = &'y isize>
+LL | | {
+LL | |     // not ok for tuple, two lifetimes and we pick second
+LL | | }
+   | |_^
 
-error: implementation of `TheTrait` is not general enough
-  --> $DIR/associated-types-eq-hr.rs:105:5
+error[E0277]: the trait bound `for<'x, 'y> Tuple: TheTrait<(&'x isize, &'y isize)>` is not satisfied
+  --> $DIR/associated-types-eq-hr.rs:107:5
    |
 LL |     tuple_four::<Tuple>();
-   |     ^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^ the trait `for<'x, 'y> TheTrait<(&'x isize, &'y isize)>` is not implemented for `Tuple`
+   |
+   = help: the following implementations were found:
+             <Tuple as TheTrait<(&'a isize, &'a isize)>>
+note: required by `tuple_four`
+  --> $DIR/associated-types-eq-hr.rs:74:1
    |
-   = note: Due to a where-clause on `tuple_four`,
-   = note: `Tuple` must implement `TheTrait<(&'0 isize, &'1 isize)>` for any two lifetimes `'0` and `'1`
-   = note: but `Tuple` only implements `TheTrait<(&'2 isize, &'2 isize)>` for some lifetime `'2`
+LL | / fn tuple_four<T>()
+LL | |     where T : for<'x,'y> TheTrait<(&'x isize, &'y isize)>
+LL | | {
+LL | |     // not ok for tuple, two lifetimes, and lifetime matching is invariant
+LL | | }
+   | |_^
 
-error: aborting due to 5 previous errors
+error: aborting due to 7 previous errors
 
-For more information about this error, try `rustc --explain E0271`.
+Some errors occurred: E0271, E0277.
+For more information about an error, try `rustc --explain E0271`.
diff --git a/src/test/ui/associated-types/cache/project-fn-ret-invariant.krisskross.stderr b/src/test/ui/associated-types/cache/project-fn-ret-invariant.krisskross.stderr
index 46901b44c4b6d..fa831ea81dcfb 100644
--- a/src/test/ui/associated-types/cache/project-fn-ret-invariant.krisskross.stderr
+++ b/src/test/ui/associated-types/cache/project-fn-ret-invariant.krisskross.stderr
@@ -9,15 +9,15 @@ LL |    let a = bar(foo, y); //[krisskross]~ ERROR E0623
    |                     ^ ...but data from `x` is returned here
 
 error[E0623]: lifetime mismatch
-  --> $DIR/project-fn-ret-invariant.rs:55:8
+  --> $DIR/project-fn-ret-invariant.rs:54:21
    |
 LL | fn transmute<'a,'b>(x: Type<'a>, y: Type<'b>) -> (Type<'a>, Type<'b>) {
-   |                                     --------     --------------------
-   |                                     |
-   |                                     this parameter and the return type are declared with different lifetimes...
-...
-LL |    (a, b) //[krisskross]~ ERROR E0623
-   |        ^ ...but data from `x` is returned here
+   |                        --------                  --------------------
+   |                        |
+   |                        this parameter and the return type are declared with different lifetimes...
+LL |    let a = bar(foo, y); //[krisskross]~ ERROR E0623
+LL |    let b = bar(foo, x); //[krisskross]~ ERROR E0623
+   |                     ^ ...but data from `y` is returned here
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/associated-types/cache/project-fn-ret-invariant.rs b/src/test/ui/associated-types/cache/project-fn-ret-invariant.rs
index dfcf31b3b1f26..54b6e3642c2ea 100644
--- a/src/test/ui/associated-types/cache/project-fn-ret-invariant.rs
+++ b/src/test/ui/associated-types/cache/project-fn-ret-invariant.rs
@@ -51,8 +51,8 @@ fn baz<'a,'b>(x: Type<'a>) -> Type<'static> {
 #[cfg(krisskross)] // two instantiations, mixing and matching: BAD
 fn transmute<'a,'b>(x: Type<'a>, y: Type<'b>) -> (Type<'a>, Type<'b>) {
    let a = bar(foo, y); //[krisskross]~ ERROR E0623
-   let b = bar(foo, x);
-   (a, b) //[krisskross]~ ERROR E0623
+   let b = bar(foo, x); //[krisskross]~ ERROR E0623
+   (a, b)
 }
 
 #[rustc_error]
diff --git a/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr b/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
index 947844c45c408..dd1212eaac91d 100644
--- a/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
+++ b/src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.stderr
@@ -1,4 +1,4 @@
-error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'a` due to conflicting requirements
+error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
   --> $DIR/project-fn-ret-invariant.rs:48:8
    |
 LL |    bar(foo, x) //[transmute]~ ERROR E0495
diff --git a/src/test/ui/associated-types/higher-ranked-projection.bad.stderr b/src/test/ui/associated-types/higher-ranked-projection.bad.stderr
index e4704494e1492..cc69e849fe144 100644
--- a/src/test/ui/associated-types/higher-ranked-projection.bad.stderr
+++ b/src/test/ui/associated-types/higher-ranked-projection.bad.stderr
@@ -1,12 +1,17 @@
-error[E0308]: mismatched types
+error[E0271]: type mismatch resolving `for<'a> <&'a _ as Mirror>::Image == _`
   --> $DIR/higher-ranked-projection.rs:25:5
    |
 LL |     foo(());
-   |     ^^^ one type is more general than the other
+   |     ^^^ expected bound lifetime parameter 'a, found concrete lifetime
    |
-   = note: expected type `Mirror`
-              found type `Mirror`
+note: required by `foo`
+  --> $DIR/higher-ranked-projection.rs:14:1
+   |
+LL | / fn foo<U, T>(_t: T)
+LL | |     where for<'a> &'a T: Mirror<Image=U>
+LL | | {}
+   | |__^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0271`.
diff --git a/src/test/ui/associated-types/higher-ranked-projection.good.stderr b/src/test/ui/associated-types/higher-ranked-projection.good.stderr
index db15ec51d87c6..165e5213e0d34 100644
--- a/src/test/ui/associated-types/higher-ranked-projection.good.stderr
+++ b/src/test/ui/associated-types/higher-ranked-projection.good.stderr
@@ -3,7 +3,7 @@ error: compilation successful
    |
 LL | / fn main() { //[good]~ ERROR compilation successful
 LL | |     foo(());
-LL | |     //[bad]~^ ERROR E0308
+LL | |     //[bad]~^ ERROR type mismatch
 LL | | }
    | |_^
 
diff --git a/src/test/ui/associated-types/higher-ranked-projection.rs b/src/test/ui/associated-types/higher-ranked-projection.rs
index 5b380c982f041..a2ea6d8f206b6 100644
--- a/src/test/ui/associated-types/higher-ranked-projection.rs
+++ b/src/test/ui/associated-types/higher-ranked-projection.rs
@@ -23,5 +23,5 @@ fn foo<U, T>(_t: T)
 #[rustc_error]
 fn main() { //[good]~ ERROR compilation successful
     foo(());
-    //[bad]~^ ERROR E0308
+    //[bad]~^ ERROR type mismatch
 }
diff --git a/src/test/ui/attr-usage-repr.rs b/src/test/ui/attr-usage-repr.rs
index 498bf4d284a73..1df2947cbe2dd 100644
--- a/src/test/ui/attr-usage-repr.rs
+++ b/src/test/ui/attr-usage-repr.rs
@@ -1,4 +1,5 @@
 #![feature(repr_simd)]
+#![feature(repr_align_enum)]
 
 #[repr(C)] //~ ERROR: attribute should be applied to struct, enum or union
 fn f() {}
@@ -18,7 +19,7 @@ struct SInt(f64, f64);
 #[repr(C)]
 enum EExtern { A, B }
 
-#[repr(align(8))] //~ ERROR: attribute should be applied to struct
+#[repr(align(8))]
 enum EAlign { A, B }
 
 #[repr(packed)] //~ ERROR: attribute should be applied to struct
diff --git a/src/test/ui/attr-usage-repr.stderr b/src/test/ui/attr-usage-repr.stderr
index 990984bbb2b3d..abb8685e4cef0 100644
--- a/src/test/ui/attr-usage-repr.stderr
+++ b/src/test/ui/attr-usage-repr.stderr
@@ -1,5 +1,5 @@
 error[E0517]: attribute should be applied to struct, enum or union
-  --> $DIR/attr-usage-repr.rs:3:8
+  --> $DIR/attr-usage-repr.rs:4:8
    |
 LL | #[repr(C)] //~ ERROR: attribute should be applied to struct, enum or union
    |        ^
@@ -7,7 +7,7 @@ LL | fn f() {}
    | --------- not a struct, enum or union
 
 error[E0517]: attribute should be applied to enum
-  --> $DIR/attr-usage-repr.rs:15:8
+  --> $DIR/attr-usage-repr.rs:16:8
    |
 LL | #[repr(i8)] //~ ERROR: attribute should be applied to enum
    |        ^^
@@ -15,15 +15,7 @@ LL | struct SInt(f64, f64);
    | ---------------------- not an enum
 
 error[E0517]: attribute should be applied to struct or union
-  --> $DIR/attr-usage-repr.rs:21:8
-   |
-LL | #[repr(align(8))] //~ ERROR: attribute should be applied to struct
-   |        ^^^^^^^^
-LL | enum EAlign { A, B }
-   | -------------------- not a struct or union
-
-error[E0517]: attribute should be applied to struct or union
-  --> $DIR/attr-usage-repr.rs:24:8
+  --> $DIR/attr-usage-repr.rs:25:8
    |
 LL | #[repr(packed)] //~ ERROR: attribute should be applied to struct
    |        ^^^^^^
@@ -31,13 +23,13 @@ LL | enum EPacked { A, B }
    | --------------------- not a struct or union
 
 error[E0517]: attribute should be applied to struct
-  --> $DIR/attr-usage-repr.rs:27:8
+  --> $DIR/attr-usage-repr.rs:28:8
    |
 LL | #[repr(simd)] //~ ERROR: attribute should be applied to struct
    |        ^^^^
 LL | enum ESimd { A, B }
    | ------------------- not a struct
 
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0517`.
diff --git a/src/test/ui/attribute-with-no-generics-in-parameter-list.rs b/src/test/ui/attribute-with-no-generics-in-parameter-list.rs
new file mode 100644
index 0000000000000..c2cc91d8f7703
--- /dev/null
+++ b/src/test/ui/attribute-with-no-generics-in-parameter-list.rs
@@ -0,0 +1,3 @@
+fn foo<#[attr]>() {} //~ ERROR attribute without generic parameters
+
+fn main() {}
diff --git a/src/test/ui/attribute-with-no-generics-in-parameter-list.stderr b/src/test/ui/attribute-with-no-generics-in-parameter-list.stderr
new file mode 100644
index 0000000000000..f08f107a62ffe
--- /dev/null
+++ b/src/test/ui/attribute-with-no-generics-in-parameter-list.stderr
@@ -0,0 +1,8 @@
+error: attribute without generic parameters
+  --> $DIR/attribute-with-no-generics-in-parameter-list.rs:1:8
+   |
+LL | fn foo<#[attr]>() {} //~ ERROR attribute without generic parameters
+   |        ^^^^^^^ attributes are only permitted when preceding parameters
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.rs b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.rs
index d7feb03853077..ca5fdd9da859b 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.rs
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.rs
@@ -7,7 +7,7 @@
 struct RefIntPair<'a, 'b>(&'a u32, &'b u32);
 
 impl<#[rustc_1] 'a, 'b, #[oops]> RefIntPair<'a, 'b> {
-    //~^ ERROR trailing attribute after lifetime parameters
+    //~^ ERROR trailing attribute after generic parameter
 }
 
 fn main() {
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.stderr b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.stderr
index c4c0cee5ccc31..55e7a9877846f 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.stderr
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-1.stderr
@@ -1,4 +1,4 @@
-error: trailing attribute after lifetime parameters
+error: trailing attribute after generic parameter
   --> $DIR/attrs-with-no-formal-in-generics-1.rs:9:25
    |
 LL | impl<#[rustc_1] 'a, 'b, #[oops]> RefIntPair<'a, 'b> {
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.rs b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.rs
index f9db6a5f72af9..c795612acf08c 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.rs
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.rs
@@ -7,6 +7,6 @@
 struct RefAny<'a, T>(&'a T);
 
 impl<#[rustc_1] 'a, #[rustc_2] T, #[oops]> RefAny<'a, T> {}
-//~^ ERROR trailing attribute after type parameters
+//~^ ERROR trailing attribute after generic parameter
 
 fn main() {}
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.stderr b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.stderr
index 9099d74ce1be9..acd0ae3678a7c 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.stderr
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-2.stderr
@@ -1,4 +1,4 @@
-error: trailing attribute after type parameters
+error: trailing attribute after generic parameter
   --> $DIR/attrs-with-no-formal-in-generics-2.rs:9:35
    |
 LL | impl<#[rustc_1] 'a, #[rustc_2] T, #[oops]> RefAny<'a, T> {}
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.rs b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.rs
index e9f908d479f64..3cfc70b41850a 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.rs
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.rs
@@ -6,7 +6,7 @@ struct RefIntPair<'a, 'b>(&'a u32, &'b u32);
 
 fn hof_lt<Q>(_: Q)
     where Q: for <#[allow(unused)] 'a, 'b, #[oops]> Fn(RefIntPair<'a,'b>) -> &'b u32
-    //~^ ERROR trailing attribute after lifetime parameters
+    //~^ ERROR trailing attribute after generic parameter
 {}
 
 fn main() {}
diff --git a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.stderr b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.stderr
index 452f0ea5e1753..b9ca00974677b 100644
--- a/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.stderr
+++ b/src/test/ui/attrs-with-no-formal-in-generics/attrs-with-no-formal-in-generics-3.stderr
@@ -1,4 +1,4 @@
-error: trailing attribute after lifetime parameters
+error: trailing attribute after generic parameter
   --> $DIR/attrs-with-no-formal-in-generics-3.rs:8:44
    |
 LL |     where Q: for <#[allow(unused)] 'a, 'b, #[oops]> Fn(RefIntPair<'a,'b>) -> &'b u32
diff --git a/src/test/ui/augmented-assignments.nll.stderr b/src/test/ui/augmented-assignments.nll.stderr
index 840b377263db9..33c94d6e3a59e 100644
--- a/src/test/ui/augmented-assignments.nll.stderr
+++ b/src/test/ui/augmented-assignments.nll.stderr
@@ -9,7 +9,7 @@ LL |       x   //~ error: use of moved value: `x`
 LL | |     //~^ value used here after move
 LL | |     +=
 LL | |     x;  //~ value moved here
-   | |     -
+   | |     ^
    | |     |
    | |_____move out of `x` occurs here
    |       borrow later used here
diff --git a/src/test/ui/auto-ref-slice-plus-ref.stderr b/src/test/ui/auto-ref-slice-plus-ref.stderr
index ab57fec0e7337..356e24d18a78f 100644
--- a/src/test/ui/auto-ref-slice-plus-ref.stderr
+++ b/src/test/ui/auto-ref-slice-plus-ref.stderr
@@ -2,12 +2,11 @@ error[E0599]: no method named `test_mut` found for type `std::vec::Vec<{integer}
   --> $DIR/auto-ref-slice-plus-ref.rs:7:7
    |
 LL |     a.test_mut(); //~ ERROR no method named `test_mut` found
-   |       ^^^^^^^^
+   |       ^^^^^^^^ help: did you mean: `get_mut`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `test_mut`, perhaps you need to implement it:
            candidate #1: `MyIter`
-   = help: did you mean `get_mut`?
 
 error[E0599]: no method named `test` found for type `std::vec::Vec<{integer}>` in the current scope
   --> $DIR/auto-ref-slice-plus-ref.rs:8:7
diff --git a/src/test/ui/bad/bad-type-env-capture.rs b/src/test/ui/bad/bad-type-env-capture.rs
index d2e6dff125273..53dfb13139a54 100644
--- a/src/test/ui/bad/bad-type-env-capture.rs
+++ b/src/test/ui/bad/bad-type-env-capture.rs
@@ -1,4 +1,4 @@
 fn foo<T>() {
-    fn bar(b: T) { } //~ ERROR can't use type parameters from outer
+    fn bar(b: T) { } //~ ERROR can't use generic parameters from outer
 }
 fn main() { }
diff --git a/src/test/ui/bad/bad-type-env-capture.stderr b/src/test/ui/bad/bad-type-env-capture.stderr
index 5558a44006180..ce803e96801f9 100644
--- a/src/test/ui/bad/bad-type-env-capture.stderr
+++ b/src/test/ui/bad/bad-type-env-capture.stderr
@@ -1,12 +1,12 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/bad-type-env-capture.rs:2:15
    |
 LL | fn foo<T>() {
    |        - type variable from outer function
-LL |     fn bar(b: T) { } //~ ERROR can't use type parameters from outer
-   |        ---    ^ use of type variable from outer function
+LL |     fn bar(b: T) { } //~ ERROR can't use generic parameters from outer
+   |        ---    ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `bar<T>`
+   |        help: try using a local generic parameter instead: `bar<T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/binop/binop-consume-args.nll.stderr b/src/test/ui/binop/binop-consume-args.nll.stderr
new file mode 100644
index 0000000000000..59b5aba93cad4
--- /dev/null
+++ b/src/test/ui/binop/binop-consume-args.nll.stderr
@@ -0,0 +1,253 @@
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:7:10
+   |
+LL | fn add<A: Add<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs + rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:8:10
+   |
+LL | fn add<A: Add<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs + rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:13:10
+   |
+LL | fn sub<A: Sub<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs - rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:14:10
+   |
+LL | fn sub<A: Sub<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs - rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:19:10
+   |
+LL | fn mul<A: Mul<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs * rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:20:10
+   |
+LL | fn mul<A: Mul<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs * rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:25:10
+   |
+LL | fn div<A: Div<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs / rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:26:10
+   |
+LL | fn div<A: Div<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs / rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:31:10
+   |
+LL | fn rem<A: Rem<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs % rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:32:10
+   |
+LL | fn rem<A: Rem<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs % rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:37:10
+   |
+LL | fn bitand<A: BitAnd<B, Output=()>, B>(lhs: A, rhs: B) {
+   |           -                           --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |           |
+   |           consider adding a `Copy` constraint to this type argument
+LL |     lhs & rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:38:10
+   |
+LL | fn bitand<A: BitAnd<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                                    -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                                    |
+   |                                    consider adding a `Copy` constraint to this type argument
+LL |     lhs & rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:43:10
+   |
+LL | fn bitor<A: BitOr<B, Output=()>, B>(lhs: A, rhs: B) {
+   |          -                          --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |          |
+   |          consider adding a `Copy` constraint to this type argument
+LL |     lhs | rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:44:10
+   |
+LL | fn bitor<A: BitOr<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                                  -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                                  |
+   |                                  consider adding a `Copy` constraint to this type argument
+LL |     lhs | rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:49:10
+   |
+LL | fn bitxor<A: BitXor<B, Output=()>, B>(lhs: A, rhs: B) {
+   |           -                           --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |           |
+   |           consider adding a `Copy` constraint to this type argument
+LL |     lhs ^ rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:50:10
+   |
+LL | fn bitxor<A: BitXor<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                                    -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                                    |
+   |                                    consider adding a `Copy` constraint to this type argument
+LL |     lhs ^ rhs;
+   |           --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:55:10
+   |
+LL | fn shl<A: Shl<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs << rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:56:10
+   |
+LL | fn shl<A: Shl<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs << rhs;
+   |            --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `lhs`
+  --> $DIR/binop-consume-args.rs:61:10
+   |
+LL | fn shr<A: Shr<B, Output=()>, B>(lhs: A, rhs: B) {
+   |        -                        --- move occurs because `lhs` has type `A`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     lhs >> rhs;
+   |     --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+   |          ^^^ value used here after move
+
+error[E0382]: use of moved value: `rhs`
+  --> $DIR/binop-consume-args.rs:62:10
+   |
+LL | fn shr<A: Shr<B, Output=()>, B>(lhs: A, rhs: B) {
+   |                              -          --- move occurs because `rhs` has type `B`, which does not implement the `Copy` trait
+   |                              |
+   |                              consider adding a `Copy` constraint to this type argument
+LL |     lhs >> rhs;
+   |            --- value moved here
+LL |     drop(lhs);  //~ ERROR use of moved value: `lhs`
+LL |     drop(rhs);  //~ ERROR use of moved value: `rhs`
+   |          ^^^ value used here after move
+
+error: aborting due to 20 previous errors
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/binop/binop-move-semantics.nll.stderr b/src/test/ui/binop/binop-move-semantics.nll.stderr
index 950772dc75c9e..7c84e8833a9e6 100644
--- a/src/test/ui/binop/binop-move-semantics.nll.stderr
+++ b/src/test/ui/binop/binop-move-semantics.nll.stderr
@@ -1,24 +1,28 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/binop-move-semantics.rs:8:5
    |
+LL | fn double_move<T: Add<Output=()>>(x: T) {
+   |                -                  - move occurs because `x` has type `T`, which does not implement the `Copy` trait
+   |                |
+   |                consider adding a `Copy` constraint to this type argument
 LL |     x
    |     - value moved here
 LL |     +
 LL |     x;  //~ ERROR: use of moved value
    |     ^ value used here after move
-   |
-   = note: move occurs because `x` has type `T`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/binop-move-semantics.rs:14:5
    |
+LL | fn move_then_borrow<T: Add<Output=()> + Clone>(x: T) {
+   |                     -                          - move occurs because `x` has type `T`, which does not implement the `Copy` trait
+   |                     |
+   |                     consider adding a `Copy` constraint to this type argument
 LL |     x
    |     - value moved here
 LL |     +
 LL |     x.clone();  //~ ERROR: use of moved value
    |     ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `T`, which does not implement the `Copy` trait
 
 error[E0505]: cannot move out of `x` because it is borrowed
   --> $DIR/binop-move-semantics.rs:21:5
diff --git a/src/test/ui/block-result/issue-3563.stderr b/src/test/ui/block-result/issue-3563.stderr
index 7f386630de590..a6346a5233f4c 100644
--- a/src/test/ui/block-result/issue-3563.stderr
+++ b/src/test/ui/block-result/issue-3563.stderr
@@ -2,9 +2,7 @@ error[E0599]: no method named `b` found for type `&Self` in the current scope
   --> $DIR/issue-3563.rs:3:17
    |
 LL |         || self.b()
-   |                 ^
-   |
-   = help: did you mean `a`?
+   |                 ^ help: did you mean: `a`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-asm.ast.nll.stderr b/src/test/ui/borrowck/borrowck-asm.ast.nll.stderr
index 9c47845a52830..86e4832b3873c 100644
--- a/src/test/ui/borrowck/borrowck-asm.ast.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-asm.ast.nll.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:27:17
    |
+LL |         let x = &mut 0isize;
+   |             - move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x));
    |                                - value moved here
 LL |         }
 LL |         let z = x;  //[ast]~ ERROR use of moved value: `x`
    |                 ^ value used here after move
-   |
-   = note: move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
 
 error[E0503]: cannot use `x` because it was mutably borrowed
   --> $DIR/borrowck-asm.rs:35:32
@@ -66,12 +67,13 @@ LL |         let z = y;
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:86:40
    |
+LL |         let x = &mut 2;
+   |             - move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x), "r"(x) );    //[ast]~ ERROR use of moved value
    |                                -       ^ value used here after move
    |                                |
    |                                value moved here
-   |
-   = note: move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-asm.mir.stderr b/src/test/ui/borrowck/borrowck-asm.mir.stderr
index 9c47845a52830..86e4832b3873c 100644
--- a/src/test/ui/borrowck/borrowck-asm.mir.stderr
+++ b/src/test/ui/borrowck/borrowck-asm.mir.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:27:17
    |
+LL |         let x = &mut 0isize;
+   |             - move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x));
    |                                - value moved here
 LL |         }
 LL |         let z = x;  //[ast]~ ERROR use of moved value: `x`
    |                 ^ value used here after move
-   |
-   = note: move occurs because `x` has type `&mut isize`, which does not implement the `Copy` trait
 
 error[E0503]: cannot use `x` because it was mutably borrowed
   --> $DIR/borrowck-asm.rs:35:32
@@ -66,12 +67,13 @@ LL |         let z = y;
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-asm.rs:86:40
    |
+LL |         let x = &mut 2;
+   |             - move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
+LL |         unsafe {
 LL |             asm!("nop" : : "r"(x), "r"(x) );    //[ast]~ ERROR use of moved value
    |                                -       ^ value used here after move
    |                                |
    |                                value moved here
-   |
-   = note: move occurs because `x` has type `&mut i32`, which does not implement the `Copy` trait
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-consume-unsize-vec.nll.stderr b/src/test/ui/borrowck/borrowck-consume-unsize-vec.nll.stderr
new file mode 100644
index 0000000000000..ea7683a91adfe
--- /dev/null
+++ b/src/test/ui/borrowck/borrowck-consume-unsize-vec.nll.stderr
@@ -0,0 +1,13 @@
+error[E0382]: use of moved value: `b`
+  --> $DIR/borrowck-consume-unsize-vec.rs:8:13
+   |
+LL | fn foo(b: Box<[i32;5]>) {
+   |        - move occurs because `b` has type `std::boxed::Box<[i32; 5]>`, which does not implement the `Copy` trait
+LL |     consume(b);
+   |             - value moved here
+LL |     consume(b); //~ ERROR use of moved value
+   |             ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/borrowck/borrowck-consume-upcast-box.nll.stderr b/src/test/ui/borrowck/borrowck-consume-upcast-box.nll.stderr
index 7357d0973dbc0..15cf359326be9 100644
--- a/src/test/ui/borrowck/borrowck-consume-upcast-box.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-consume-upcast-box.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `b`
   --> $DIR/borrowck-consume-upcast-box.rs:10:13
    |
+LL | fn foo(b: Box<Foo+Send>) {
+   |        - move occurs because `b` has type `std::boxed::Box<dyn Foo + std::marker::Send>`, which does not implement the `Copy` trait
 LL |     consume(b);
    |             - value moved here
 LL |     consume(b); //~ ERROR use of moved value
    |             ^ value used here after move
-   |
-   = note: move occurs because `b` has type `std::boxed::Box<dyn Foo + std::marker::Send>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-drop-from-guard.stderr b/src/test/ui/borrowck/borrowck-drop-from-guard.stderr
index d395b7734f9b7..07b597f480feb 100644
--- a/src/test/ui/borrowck/borrowck-drop-from-guard.stderr
+++ b/src/test/ui/borrowck/borrowck-drop-from-guard.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `my_str`
   --> $DIR/borrowck-drop-from-guard.rs:11:23
    |
+LL |     let my_str = "hello".to_owned();
+   |         ------ move occurs because `my_str` has type `std::string::String`, which does not implement the `Copy` trait
+LL |     match Some(42) {
 LL |         Some(_) if { drop(my_str); false } => {}
    |                           ------ value moved here
 LL |         Some(_) => {}
 LL |         None => { foo(my_str); } //~ ERROR [E0382]
    |                       ^^^^^^ value used here after move
-   |
-   = note: move occurs because `my_str` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-for-loop-head-linkage.nll.stderr b/src/test/ui/borrowck/borrowck-for-loop-head-linkage.nll.stderr
index c0549c91e33a3..32ca24ba6ec43 100644
--- a/src/test/ui/borrowck/borrowck-for-loop-head-linkage.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-for-loop-head-linkage.nll.stderr
@@ -5,7 +5,7 @@ LL |     for &x in &vector {
    |               -------
    |               |
    |               immutable borrow occurs here
-   |               immutable borrow used here, in later iteration of loop
+   |               immutable borrow later used here
 LL |         let cap = vector.capacity();
 LL |         vector.extend(repeat(0));      //~ ERROR cannot borrow
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ mutable borrow occurs here
@@ -17,7 +17,7 @@ LL |     for &x in &vector {
    |               -------
    |               |
    |               immutable borrow occurs here
-   |               immutable borrow used here, in later iteration of loop
+   |               immutable borrow later used here
 ...
 LL |         vector[1] = 5;   //~ ERROR cannot borrow
    |         ^^^^^^ mutable borrow occurs here
diff --git a/src/test/ui/borrowck/borrowck-issue-48962.stderr b/src/test/ui/borrowck/borrowck-issue-48962.stderr
index 9d53d82265eca..de4894d5b526b 100644
--- a/src/test/ui/borrowck/borrowck-issue-48962.stderr
+++ b/src/test/ui/borrowck/borrowck-issue-48962.stderr
@@ -1,22 +1,22 @@
 error[E0382]: use of moved value: `src`
   --> $DIR/borrowck-issue-48962.rs:16:5
    |
+LL |     let mut src = &mut node;
+   |         ------- move occurs because `src` has type `&mut Node`, which does not implement the `Copy` trait
 LL |     {src};
    |      --- value moved here
 LL |     src.next = None; //~ ERROR use of moved value: `src` [E0382]
    |     ^^^^^^^^ value used here after move
-   |
-   = note: move occurs because `src` has type `&mut Node`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `src`
   --> $DIR/borrowck-issue-48962.rs:22:5
    |
+LL |     let mut src = &mut (22, 44);
+   |         ------- move occurs because `src` has type `&mut (i32, i32)`, which does not implement the `Copy` trait
 LL |     {src};
    |      --- value moved here
 LL |     src.0 = 66; //~ ERROR use of moved value: `src` [E0382]
    |     ^^^^^^^^^^ value used here after move
-   |
-   = note: move occurs because `src` has type `&mut (i32, i32)`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-lend-flow-loop.nll.stderr b/src/test/ui/borrowck/borrowck-lend-flow-loop.nll.stderr
index 19de3582c8819..396fd6ffa0c6b 100644
--- a/src/test/ui/borrowck/borrowck-lend-flow-loop.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-lend-flow-loop.nll.stderr
@@ -8,13 +8,13 @@ LL |         borrow(&*v); //[ast]~ ERROR cannot borrow
    |                ^^^ immutable borrow occurs here
 ...
 LL |     *x = box 5;
-   |     -- mutable borrow used here, in later iteration of loop
+   |     -- mutable borrow later used here
 
 error[E0502]: cannot borrow `*v` as immutable because it is also borrowed as mutable
   --> $DIR/borrowck-lend-flow-loop.rs:109:16
    |
 LL |         **x += 1;
-   |         -------- mutable borrow used here, in later iteration of loop
+   |         -------- mutable borrow later used here
 LL |         borrow(&*v); //[ast]~ ERROR cannot borrow
    |                ^^^ immutable borrow occurs here
 ...
diff --git a/src/test/ui/borrowck/borrowck-loan-in-overloaded-op.nll.stderr b/src/test/ui/borrowck/borrowck-loan-in-overloaded-op.nll.stderr
index 72d2d1fe59f66..095ae7f56b22e 100644
--- a/src/test/ui/borrowck/borrowck-loan-in-overloaded-op.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-loan-in-overloaded-op.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/borrowck-loan-in-overloaded-op.rs:21:20
    |
+LL |     let x = Foo(box 3);
+   |         - move occurs because `x` has type `Foo`, which does not implement the `Copy` trait
 LL |     let _y = {x} + x.clone(); // the `{x}` forces a move to occur
    |               -    ^ value borrowed here after move
    |               |
    |               value moved here
-   |
-   = note: move occurs because `x` has type `Foo`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.ast.nll.stderr b/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.ast.nll.stderr
index 24b9b4338a58c..0789926563ce7 100644
--- a/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.ast.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.ast.nll.stderr
@@ -1,6 +1,9 @@
 error[E0382]: use of moved value: `t`
   --> $DIR/borrowck-move-moved-value-into-closure.rs:14:12
    |
+LL |     let t: Box<_> = box 3;
+   |         - move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+LL | 
 LL |     call_f(move|| { *t + 1 });
    |            ------    - variable moved due to use in closure
    |            |
@@ -9,8 +12,6 @@ LL |     call_f(move|| { *t + 1 }); //[ast]~ ERROR capture of moved value
    |            ^^^^^^    - use occurs due to use in closure
    |            |
    |            value used here after move
-   |
-   = note: move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr b/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr
index 24b9b4338a58c..0789926563ce7 100644
--- a/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr
+++ b/src/test/ui/borrowck/borrowck-move-moved-value-into-closure.mir.stderr
@@ -1,6 +1,9 @@
 error[E0382]: use of moved value: `t`
   --> $DIR/borrowck-move-moved-value-into-closure.rs:14:12
    |
+LL |     let t: Box<_> = box 3;
+   |         - move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+LL | 
 LL |     call_f(move|| { *t + 1 });
    |            ------    - variable moved due to use in closure
    |            |
@@ -9,8 +12,6 @@ LL |     call_f(move|| { *t + 1 }); //[ast]~ ERROR capture of moved value
    |            ^^^^^^    - use occurs due to use in closure
    |            |
    |            value used here after move
-   |
-   = note: move occurs because `t` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-multiple-captures.nll.stderr b/src/test/ui/borrowck/borrowck-multiple-captures.nll.stderr
index 6f4cad2a01e48..d0065a2e7dc3d 100644
--- a/src/test/ui/borrowck/borrowck-multiple-captures.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-multiple-captures.nll.stderr
@@ -29,6 +29,8 @@ LL |     borrow(&*p2);
 error[E0382]: use of moved value: `x1`
   --> $DIR/borrowck-multiple-captures.rs:25:19
    |
+LL |     let x1: Box<_> = box 1;
+   |         -- move occurs because `x1` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 LL |     drop(x1);
    |          -- value moved here
 ...
@@ -36,12 +38,12 @@ LL |     thread::spawn(move|| {
    |                   ^^^^^^ value used here after move
 LL |         drop(x1); //~ ERROR capture of moved value: `x1`
    |              -- use occurs due to use in closure
-   |
-   = note: move occurs because `x1` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x2`
   --> $DIR/borrowck-multiple-captures.rs:25:19
    |
+LL |     let x2: Box<_> = box 2;
+   |         -- move occurs because `x2` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 LL |     drop(x2);
    |          -- value moved here
 LL |     thread::spawn(move|| {
@@ -49,8 +51,6 @@ LL |     thread::spawn(move|| {
 LL |         drop(x1); //~ ERROR capture of moved value: `x1`
 LL |         drop(x2); //~ ERROR capture of moved value: `x2`
    |              -- use occurs due to use in closure
-   |
-   = note: move occurs because `x2` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-multiple-captures.rs:36:14
@@ -88,14 +88,14 @@ LL |         drop(x); //~ ERROR use of moved value: `x`
 error[E0382]: use of moved value: `x`
   --> $DIR/borrowck-multiple-captures.rs:44:19
    |
+LL |     let x: Box<_> = box 1;
+   |         - move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 LL |     drop(x);
    |          - value moved here
 LL |     thread::spawn(move|| {
    |                   ^^^^^^ value used here after move
 LL |         drop(x); //~ ERROR capture of moved value: `x`
    |              - use occurs due to use in closure
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.ast.nll.stderr b/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.ast.nll.stderr
index 806c3a623bc68..0f07776533608 100644
--- a/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.ast.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.ast.nll.stderr
@@ -4,7 +4,7 @@ error[E0499]: cannot borrow `x` as mutable more than once at a time
 LL |             1 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                    ----      ^^^^^^ second mutable borrow occurs here
    |                    |
-   |                    first borrow used here, in later iteration of loop
+   |                    first borrow later used here
 ...
 LL |             _ => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                              ------ first mutable borrow occurs here
@@ -13,7 +13,7 @@ error[E0499]: cannot borrow `x` as mutable more than once at a time
   --> $DIR/borrowck-mut-borrow-linear-errors.rs:15:30
    |
 LL |             1 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
-   |                    ---- first borrow used here, in later iteration of loop
+   |                    ---- first borrow later used here
 LL |             //[mir]~^ ERROR [E0499]
 LL |             2 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                              ^^^^^^ second mutable borrow occurs here
diff --git a/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.mir.stderr b/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.mir.stderr
index 806c3a623bc68..0f07776533608 100644
--- a/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.mir.stderr
+++ b/src/test/ui/borrowck/borrowck-mut-borrow-linear-errors.mir.stderr
@@ -4,7 +4,7 @@ error[E0499]: cannot borrow `x` as mutable more than once at a time
 LL |             1 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                    ----      ^^^^^^ second mutable borrow occurs here
    |                    |
-   |                    first borrow used here, in later iteration of loop
+   |                    first borrow later used here
 ...
 LL |             _ => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                              ------ first mutable borrow occurs here
@@ -13,7 +13,7 @@ error[E0499]: cannot borrow `x` as mutable more than once at a time
   --> $DIR/borrowck-mut-borrow-linear-errors.rs:15:30
    |
 LL |             1 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
-   |                    ---- first borrow used here, in later iteration of loop
+   |                    ---- first borrow later used here
 LL |             //[mir]~^ ERROR [E0499]
 LL |             2 => { addr.push(&mut x); } //[ast]~ ERROR [E0499]
    |                              ^^^^^^ second mutable borrow occurs here
diff --git a/src/test/ui/borrowck/borrowck-overloaded-call.nll.stderr b/src/test/ui/borrowck/borrowck-overloaded-call.nll.stderr
index 1b4a6610ab1a4..c5a4c4e005aa7 100644
--- a/src/test/ui/borrowck/borrowck-overloaded-call.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-overloaded-call.nll.stderr
@@ -20,12 +20,13 @@ LL |     s(3);   //~ ERROR cannot borrow immutable local variable `s` as mutable
 error[E0382]: use of moved value: `s`
   --> $DIR/borrowck-overloaded-call.rs:75:5
    |
+LL |     let s = SFnOnce {
+   |         - move occurs because `s` has type `SFnOnce`, which does not implement the `Copy` trait
+...
 LL |     s(" world".to_string());
    |     - value moved here
 LL |     s(" world".to_string());    //~ ERROR use of moved value: `s`
    |     ^ value used here after move
-   |
-   = note: move occurs because `s` has type `SFnOnce`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-overloaded-index-move-index.nll.stderr b/src/test/ui/borrowck/borrowck-overloaded-index-move-index.nll.stderr
index a19baa167de91..de60067f1a613 100644
--- a/src/test/ui/borrowck/borrowck-overloaded-index-move-index.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-overloaded-index-move-index.nll.stderr
@@ -25,13 +25,14 @@ LL |     use_mut(rs);
 error[E0382]: use of moved value: `s`
   --> $DIR/borrowck-overloaded-index-move-index.rs:53:7
    |
+LL |     let mut s = "hello".to_string();
+   |         ----- move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |     println!("{}", f[s]);
    |                      - value moved here
 ...
 LL |     f[s] = 10;
    |       ^ value used here after move
-   |
-   = note: move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-partial-reinit-1.nll.stderr b/src/test/ui/borrowck/borrowck-partial-reinit-1.nll.stderr
index 09a85bd7c13a9..65f2bd6cfbda9 100644
--- a/src/test/ui/borrowck/borrowck-partial-reinit-1.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-partial-reinit-1.nll.stderr
@@ -1,22 +1,24 @@
 error[E0382]: assign of moved value: `t`
   --> $DIR/borrowck-partial-reinit-1.rs:27:5
    |
+LL |     let mut t = Test2 { b: None };
+   |         ----- move occurs because `t` has type `Test2`, which does not implement the `Copy` trait
+LL |     let u = Test;
 LL |     drop(t);
    |          - value moved here
 LL |     t.b = Some(u);
    |     ^^^ value assigned here after move
-   |
-   = note: move occurs because `t` has type `Test2`, which does not implement the `Copy` trait
 
 error[E0382]: assign of moved value: `t`
   --> $DIR/borrowck-partial-reinit-1.rs:33:5
    |
+LL |     let mut t = Test3(None);
+   |         ----- move occurs because `t` has type `Test3`, which does not implement the `Copy` trait
+LL |     let u = Test;
 LL |     drop(t);
    |          - value moved here
 LL |     t.0 = Some(u);
    |     ^^^ value assigned here after move
-   |
-   = note: move occurs because `t` has type `Test3`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-partial-reinit-2.nll.stderr b/src/test/ui/borrowck/borrowck-partial-reinit-2.nll.stderr
index 03608a1b99d24..36a871fbb12a1 100644
--- a/src/test/ui/borrowck/borrowck-partial-reinit-2.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-partial-reinit-2.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: assign of moved value: `t`
   --> $DIR/borrowck-partial-reinit-2.rs:15:5
    |
+LL |     let mut t = Test { a: 1, b: None};
+   |         ----- move occurs because `t` has type `Test`, which does not implement the `Copy` trait
 LL |     let mut u = Test { a: 2, b: Some(Box::new(t))};
    |                                               - value moved here
 LL |     t.b = Some(Box::new(u));
    |     ^^^ value assigned here after move
-   |
-   = note: move occurs because `t` has type `Test`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-reinit.stderr b/src/test/ui/borrowck/borrowck-reinit.stderr
index 918452726a06c..96f3981ac2fe6 100644
--- a/src/test/ui/borrowck/borrowck-reinit.stderr
+++ b/src/test/ui/borrowck/borrowck-reinit.stderr
@@ -11,12 +11,13 @@ LL |     let _ = (1,x); //~ ERROR use of moved value: `x` (Ast)
 error[E0382]: use of moved value: `x` (Mir)
   --> $DIR/borrowck-reinit.rs:8:16
    |
+LL |     let mut x = Box::new(0);
+   |         ----- move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+...
 LL |     drop(x);
    |          - value moved here
 LL |     let _ = (1,x); //~ ERROR use of moved value: `x` (Ast)
    |                ^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-unboxed-closures.nll.stderr b/src/test/ui/borrowck/borrowck-unboxed-closures.nll.stderr
index 86baa0db96121..363a5a69a07e3 100644
--- a/src/test/ui/borrowck/borrowck-unboxed-closures.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-unboxed-closures.nll.stderr
@@ -19,12 +19,14 @@ LL |     f(1, 2);    //~ ERROR cannot borrow immutable argument
 error[E0382]: use of moved value: `f`
   --> $DIR/borrowck-unboxed-closures.rs:12:5
    |
+LL | fn c<F:FnOnce(isize, isize) -> isize>(f: F) {
+   |      -                                - move occurs because `f` has type `F`, which does not implement the `Copy` trait
+   |      |
+   |      consider adding a `Copy` constraint to this type argument
 LL |     f(1, 2);
    |     - value moved here
 LL |     f(1, 2);    //~ ERROR use of moved value
    |     ^ value used here after move
-   |
-   = note: move occurs because `f` has type `F`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr b/src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr
index bf0d0a45fcff7..e59fef2dc0d2f 100644
--- a/src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move-assign.rs:17:21
    |
+LL |             let mut u = U { a: A };
+   |                 ----- move occurs because `u` has type `U`, which does not implement the `Copy` trait
 LL |             let a = u.a;
    |                     --- value moved here
 LL |             let a = u.a; //~ ERROR use of moved value: `u.a`
    |                     ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `U`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/borrowck/borrowck-union-move.nll.stderr b/src/test/ui/borrowck/borrowck-union-move.nll.stderr
index fd90fc47a218d..1392a7931c30a 100644
--- a/src/test/ui/borrowck/borrowck-union-move.nll.stderr
+++ b/src/test/ui/borrowck/borrowck-union-move.nll.stderr
@@ -1,62 +1,62 @@
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:26:21
    |
+LL |             let mut u = Unn { n1: NonCopy };
+   |                 ----- move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 LL |             let a = u.n1;
    |                     ---- value moved here
 LL |             let a = u.n1; //~ ERROR use of moved value: `u.n1`
    |                     ^^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:31:21
    |
+LL |             let mut u = Unn { n1: NonCopy };
+   |                 ----- move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 LL |             let a = u.n1;
    |                     ---- value moved here
 LL |             let a = u; //~ ERROR use of partially moved value: `u`
    |                     ^ value used here after move
-   |
-   = note: move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:36:21
    |
+LL |             let mut u = Unn { n1: NonCopy };
+   |                 ----- move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 LL |             let a = u.n1;
    |                     ---- value moved here
 LL |             let a = u.n2; //~ ERROR use of moved value: `u.n2`
    |                     ^^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `Unn`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:63:21
    |
+LL |             let mut u = Ucn { c: Copy };
+   |                 ----- move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 LL |             let a = u.n;
    |                     --- value moved here
 LL |             let a = u.n; //~ ERROR use of moved value: `u.n`
    |                     ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:68:21
    |
+LL |             let mut u = Ucn { c: Copy };
+   |                 ----- move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 LL |             let a = u.n;
    |                     --- value moved here
 LL |             let a = u.c; //~ ERROR use of moved value: `u.c`
    |                     ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `u`
   --> $DIR/borrowck-union-move.rs:83:21
    |
+LL |             let mut u = Ucn { c: Copy };
+   |                 ----- move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 LL |             let a = u.n;
    |                     --- value moved here
 LL |             let a = u; //~ ERROR use of partially moved value: `u`
    |                     ^ value used here after move
-   |
-   = note: move occurs because `u` has type `Ucn`, which does not implement the `Copy` trait
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/borrowck/issue-47215-ice-from-drop-elab.rs b/src/test/ui/borrowck/issue-47215-ice-from-drop-elab.rs
index 670c6bb869d59..7477947b89ca4 100644
--- a/src/test/ui/borrowck/issue-47215-ice-from-drop-elab.rs
+++ b/src/test/ui/borrowck/issue-47215-ice-from-drop-elab.rs
@@ -10,7 +10,7 @@
 #![feature(thread_local)]
 
 #[thread_local]
-static mut X: ::std::sync::atomic::AtomicUsize = ::std::sync::atomic::ATOMIC_USIZE_INIT;
+static mut X: ::std::sync::atomic::AtomicUsize = ::std::sync::atomic::AtomicUsize::new(0);
 
 fn main() {
     unsafe {
diff --git a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr
index 7861087ad02eb..42aa038170238 100644
--- a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr
+++ b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out-with-mut.nll.stderr
@@ -1,32 +1,32 @@
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:23:9
    |
+LL |         let mut t: Tuple = (S(0), 0);
+   |             ----- move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 LL |         drop(t);
    |              - value moved here
 LL |         t.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `u`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:34:9
    |
+LL |         let mut u: Tpair = Tpair(S(0), 0);
+   |             ----- move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 LL |         drop(u);
    |              - value moved here
 LL |         u.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `v`
   --> $DIR/issue-54499-field-mutation-of-moved-out-with-mut.rs:45:9
    |
+LL |         let mut v: Spair = Spair { x: S(0), y: 0 };
+   |             ----- move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 LL |         drop(v);
    |              - value moved here
 LL |         v.x = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr
index d35d0058027d4..1184907f307cb 100644
--- a/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr
+++ b/src/test/ui/borrowck/issue-54499-field-mutation-of-moved-out.nll.stderr
@@ -10,12 +10,12 @@ LL |         t.0 = S(1);
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:23:9
    |
+LL |         let t: Tuple = (S(0), 0);
+   |             - move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 LL |         drop(t);
    |              - value moved here
 LL |         t.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(S, i32)`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `t.1`, as `t` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:27:9
@@ -38,12 +38,12 @@ LL |         u.0 = S(1);
 error[E0382]: assign to part of moved value: `u`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:38:9
    |
+LL |         let u: Tpair = Tpair(S(0), 0);
+   |             - move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 LL |         drop(u);
    |              - value moved here
 LL |         u.0 = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `u` has type `Tpair`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `u.1`, as `u` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:42:9
@@ -66,12 +66,12 @@ LL |         v.x = S(1);
 error[E0382]: assign to part of moved value: `v`
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:53:9
    |
+LL |         let v: Spair = Spair { x: S(0), y: 0 };
+   |             - move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 LL |         drop(v);
    |              - value moved here
 LL |         v.x = S(1);
    |         ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `v` has type `Spair`, which does not implement the `Copy` trait
 
 error[E0594]: cannot assign to `v.y`, as `v` is not declared as mutable
   --> $DIR/issue-54499-field-mutation-of-moved-out.rs:57:9
diff --git a/src/test/ui/borrowck/mut-borrow-outside-loop.nll.stderr b/src/test/ui/borrowck/mut-borrow-outside-loop.nll.stderr
index 7e183116c4630..9b20fc0231934 100644
--- a/src/test/ui/borrowck/mut-borrow-outside-loop.nll.stderr
+++ b/src/test/ui/borrowck/mut-borrow-outside-loop.nll.stderr
@@ -17,7 +17,7 @@ LL |         let inner_second = &mut inner_void; //~ ERROR cannot borrow
    |                            ^^^^^^^^^^^^^^^ second mutable borrow occurs here
 LL |         inner_second.use_mut();
 LL |         inner_first.use_mut();
-   |         ----------- first borrow used here, in later iteration of loop
+   |         ----------- first borrow later used here
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/borrowck/two-phase-nonrecv-autoref.ast.nll.stderr b/src/test/ui/borrowck/two-phase-nonrecv-autoref.ast.nll.stderr
index 0e99e158eda02..d026f81b7aad6 100644
--- a/src/test/ui/borrowck/two-phase-nonrecv-autoref.ast.nll.stderr
+++ b/src/test/ui/borrowck/two-phase-nonrecv-autoref.ast.nll.stderr
@@ -10,6 +10,8 @@ LL |         f(f(10));
 error[E0382]: use of moved value: `*f`
   --> $DIR/two-phase-nonrecv-autoref.rs:69:11
    |
+LL |     fn twice_ten_so<F: FnOnce(i32) -> i32>(f: Box<F>) {
+   |                     - consider adding a `Copy` constraint to this type argument
 LL |         f(f(10));
    |         - ^ value used here after move
    |         |
diff --git a/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr b/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr
index 0e99e158eda02..d026f81b7aad6 100644
--- a/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr
+++ b/src/test/ui/borrowck/two-phase-nonrecv-autoref.nll.stderr
@@ -10,6 +10,8 @@ LL |         f(f(10));
 error[E0382]: use of moved value: `*f`
   --> $DIR/two-phase-nonrecv-autoref.rs:69:11
    |
+LL |     fn twice_ten_so<F: FnOnce(i32) -> i32>(f: Box<F>) {
+   |                     - consider adding a `Copy` constraint to this type argument
 LL |         f(f(10));
    |         - ^ value used here after move
    |         |
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.rs b/src/test/ui/cast/cast-ptr-to-int-const.rs
index 70b4869ef63ce..ac153cb57423f 100644
--- a/src/test/ui/cast/cast-ptr-to-int-const.rs
+++ b/src/test/ui/cast/cast-ptr-to-int-const.rs
@@ -1,7 +1,11 @@
 // gate-test-const_raw_ptr_to_usize_cast
 
 fn main() {
-    const X: u32 = main as u32; //~ ERROR casting pointers to integers in constants is unstable
+    const X: u32 = unsafe {
+        main as u32 //~ ERROR casting pointers to integers in constants is unstable
+    };
     const Y: u32 = 0;
-    const Z: u32 = &Y as *const u32 as u32; //~ ERROR is unstable
+    const Z: u32 = unsafe {
+        &Y as *const u32 as u32 //~ ERROR is unstable
+    };
 }
diff --git a/src/test/ui/cast/cast-ptr-to-int-const.stderr b/src/test/ui/cast/cast-ptr-to-int-const.stderr
index 3cce07d64ecd0..d04595ee4e887 100644
--- a/src/test/ui/cast/cast-ptr-to-int-const.stderr
+++ b/src/test/ui/cast/cast-ptr-to-int-const.stderr
@@ -1,16 +1,16 @@
 error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
-  --> $DIR/cast-ptr-to-int-const.rs:4:20
+  --> $DIR/cast-ptr-to-int-const.rs:5:9
    |
-LL |     const X: u32 = main as u32; //~ ERROR casting pointers to integers in constants is unstable
-   |                    ^^^^^^^^^^^
+LL |         main as u32 //~ ERROR casting pointers to integers in constants is unstable
+   |         ^^^^^^^^^^^
    |
    = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
 error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
-  --> $DIR/cast-ptr-to-int-const.rs:6:20
+  --> $DIR/cast-ptr-to-int-const.rs:9:9
    |
-LL |     const Z: u32 = &Y as *const u32 as u32; //~ ERROR is unstable
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^
+LL |         &Y as *const u32 as u32 //~ ERROR is unstable
+   |         ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
diff --git a/src/test/ui/closure-expected-type/expect-fn-supply-fn.rs b/src/test/ui/closure-expected-type/expect-fn-supply-fn.rs
index 6977fd47a2e85..a4e43da91baf8 100644
--- a/src/test/ui/closure-expected-type/expect-fn-supply-fn.rs
+++ b/src/test/ui/closure-expected-type/expect-fn-supply-fn.rs
@@ -28,14 +28,14 @@ fn expect_free_supply_bound() {
     // Here, we are given a function whose region is bound at closure level,
     // but we expect one bound in the argument. Error results.
     with_closure_expecting_fn_with_free_region(|x: fn(&u32), y| {});
-    //~^ ERROR mismatched types
+    //~^ ERROR type mismatch
 }
 
 fn expect_bound_supply_free_from_fn<'x>(x: &'x u32) {
     // Here, we are given a `fn(&u32)` but we expect a `fn(&'x
     // u32)`. In principle, this could be ok, but we demand equality.
     with_closure_expecting_fn_with_bound_region(|x: fn(&'x u32), y| {});
-    //~^ ERROR mismatched types
+    //~^ ERROR type mismatch
 }
 
 fn expect_bound_supply_free_from_closure() {
@@ -44,7 +44,7 @@ fn expect_bound_supply_free_from_closure() {
     // the argument level.
     type Foo<'a> = fn(&'a u32);
     with_closure_expecting_fn_with_bound_region(|x: Foo<'_>, y| {
-    //~^ ERROR mismatched types
+    //~^ ERROR type mismatch
     });
 }
 
diff --git a/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr b/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
index b1cfd6cef1022..ab35aeff697b7 100644
--- a/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
+++ b/src/test/ui/closure-expected-type/expect-fn-supply-fn.stderr
@@ -36,33 +36,58 @@ note: ...does not necessarily outlive the anonymous lifetime #2 defined on the b
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&'x u32), y| {});
    |                                                ^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0308]: mismatched types
-  --> $DIR/expect-fn-supply-fn.rs:30:52
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/expect-fn-supply-fn.rs:30:5
    |
 LL |     with_closure_expecting_fn_with_free_region(|x: fn(&u32), y| {});
-   |                                                    ^^^^^^^^ one type is more general than the other
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ---------------- found signature of `fn(for<'r> fn(&'r u32), _) -> _`
+   |     |
+   |     expected signature of `fn(fn(&'a u32), &i32) -> _`
    |
-   = note: expected type `fn(&u32)`
-              found type `for<'r> fn(&'r u32)`
+note: required by `with_closure_expecting_fn_with_free_region`
+  --> $DIR/expect-fn-supply-fn.rs:1:1
+   |
+LL | / fn with_closure_expecting_fn_with_free_region<F>(_: F)
+LL | |     where F: for<'a> FnOnce(fn(&'a u32), &i32)
+LL | | {
+LL | | }
+   | |_^
 
-error[E0308]: mismatched types
-  --> $DIR/expect-fn-supply-fn.rs:37:53
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/expect-fn-supply-fn.rs:37:5
    |
 LL |     with_closure_expecting_fn_with_bound_region(|x: fn(&'x u32), y| {});
-   |                                                     ^^^^^^^^^^^ one type is more general than the other
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ------------------- found signature of `fn(fn(&'x u32), _) -> _`
+   |     |
+   |     expected signature of `fn(for<'r> fn(&'r u32), &i32) -> _`
    |
-   = note: expected type `for<'r> fn(&'r u32)`
-              found type `fn(&'x u32)`
+note: required by `with_closure_expecting_fn_with_bound_region`
+  --> $DIR/expect-fn-supply-fn.rs:6:1
+   |
+LL | / fn with_closure_expecting_fn_with_bound_region<F>(_: F)
+LL | |     where F: FnOnce(fn(&u32), &i32)
+LL | | {
+LL | | }
+   | |_^
 
-error[E0308]: mismatched types
-  --> $DIR/expect-fn-supply-fn.rs:46:53
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/expect-fn-supply-fn.rs:46:5
    |
 LL |     with_closure_expecting_fn_with_bound_region(|x: Foo<'_>, y| {
-   |                                                     ^^^^^^^ one type is more general than the other
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ --------------- found signature of `for<'r> fn(fn(&'r u32), _) -> _`
+   |     |
+   |     expected signature of `fn(for<'r> fn(&'r u32), &i32) -> _`
+   |
+note: required by `with_closure_expecting_fn_with_bound_region`
+  --> $DIR/expect-fn-supply-fn.rs:6:1
    |
-   = note: expected type `for<'r> fn(&'r u32)`
-              found type `fn(&u32)`
+LL | / fn with_closure_expecting_fn_with_bound_region<F>(_: F)
+LL | |     where F: FnOnce(fn(&u32), &i32)
+LL | | {
+LL | | }
+   | |_^
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
+Some errors occurred: E0308, E0631.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/codemap_tests/tab_3.nll.stderr b/src/test/ui/codemap_tests/tab_3.nll.stderr
index 55117ff2b1876..3b8507a067ded 100644
--- a/src/test/ui/codemap_tests/tab_3.nll.stderr
+++ b/src/test/ui/codemap_tests/tab_3.nll.stderr
@@ -1,13 +1,13 @@
 error[E0382]: borrow of moved value: `some_vec`
   --> $DIR/tab_3.rs:7:20
    |
+LL |     let some_vec = vec!["hi"];
+   |         -------- move occurs because `some_vec` has type `std::vec::Vec<&str>`, which does not implement the `Copy` trait
 LL |     some_vec.into_iter();
    |     -------- value moved here
 LL |     {
 LL |         println!("{:?}", some_vec); //~ ERROR use of moved
    |                          ^^^^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `some_vec` has type `std::vec::Vec<&str>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/coherence/coherence-subtyping.old.stderr b/src/test/ui/coherence/coherence-subtyping.old.stderr
deleted file mode 100644
index db9f9f7665374..0000000000000
--- a/src/test/ui/coherence/coherence-subtyping.old.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error[E0119]: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
-  --> $DIR/coherence-subtyping.rs:15:1
-   |
-LL | impl TheTrait for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
-   | --------------------------------------------------------- first implementation here
-...
-LL | impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
-   |
-   = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0119`.
diff --git a/src/test/ui/coherence/coherence-subtyping.re.stderr b/src/test/ui/coherence/coherence-subtyping.re.stderr
deleted file mode 100644
index db9f9f7665374..0000000000000
--- a/src/test/ui/coherence/coherence-subtyping.re.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error[E0119]: conflicting implementations of trait `TheTrait` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
-  --> $DIR/coherence-subtyping.rs:15:1
-   |
-LL | impl TheTrait for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
-   | --------------------------------------------------------- first implementation here
-...
-LL | impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
-   |
-   = note: this behavior recently changed as a result of a bug fix; see rust-lang/rust#56105 for details
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0119`.
diff --git a/src/test/ui/coherence/coherence-subtyping.rs b/src/test/ui/coherence/coherence-subtyping.rs
index f27e14eab63da..e74067578069e 100644
--- a/src/test/ui/coherence/coherence-subtyping.rs
+++ b/src/test/ui/coherence/coherence-subtyping.rs
@@ -1,7 +1,11 @@
 // Test that two distinct impls which match subtypes of one another
 // yield coherence errors (or not) depending on the variance.
+//
+// Note: This scenario is currently accepted, but as part of the
+// universe transition (#56105) may eventually become an error.
 
 // revisions: old re
+// compile-pass
 
 #![cfg_attr(re, feature(re_rebalance_coherence))]
 
@@ -13,8 +17,6 @@ impl TheTrait for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
 }
 
 impl TheTrait for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
-    //[old]~^ ERROR
-    //[re]~^^ ERROR
 }
 
 fn main() { }
diff --git a/src/test/ui/const-generics/const-expression-parameter.rs b/src/test/ui/const-generics/const-expression-parameter.rs
new file mode 100644
index 0000000000000..f4e9008dbd0f1
--- /dev/null
+++ b/src/test/ui/const-generics/const-expression-parameter.rs
@@ -0,0 +1,23 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+fn u32_identity<const X: u32>() -> u32 {
+    //~^ ERROR const generics in any position are currently unsupported
+    5
+}
+
+fn foo_a() {
+    u32_identity::<-1>(); //~ ERROR expected identifier, found `<-`
+}
+
+fn foo_b() {
+    u32_identity::<1 + 2>(); //~ ERROR expected one of `,` or `>`, found `+`
+}
+
+fn foo_c() {
+    u32_identity::< -1 >(); // ok
+}
+
+fn main() {
+    u32_identity::<5>(); // ok
+}
diff --git a/src/test/ui/const-generics/const-expression-parameter.stderr b/src/test/ui/const-generics/const-expression-parameter.stderr
new file mode 100644
index 0000000000000..1dd3a960316d9
--- /dev/null
+++ b/src/test/ui/const-generics/const-expression-parameter.stderr
@@ -0,0 +1,26 @@
+error: expected identifier, found `<-`
+  --> $DIR/const-expression-parameter.rs:10:19
+   |
+LL |     u32_identity::<-1>(); //~ ERROR expected identifier, found `<-`
+   |                   ^^ expected identifier
+
+error: expected one of `,` or `>`, found `+`
+  --> $DIR/const-expression-parameter.rs:14:22
+   |
+LL |     u32_identity::<1 + 2>(); //~ ERROR expected one of `,` or `>`, found `+`
+   |                      ^ expected one of `,` or `>` here
+
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-expression-parameter.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-expression-parameter.rs:4:23
+   |
+LL | fn u32_identity<const X: u32>() -> u32 {
+   |                       ^
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/const-generics/const-fn-with-const-param.rs b/src/test/ui/const-generics/const-fn-with-const-param.rs
new file mode 100644
index 0000000000000..052d723d96edb
--- /dev/null
+++ b/src/test/ui/const-generics/const-fn-with-const-param.rs
@@ -0,0 +1,12 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+const fn const_u32_identity<const X: u32>() -> u32 {
+    //~^ ERROR const parameters are not permitted in `const fn`
+    //~^^ ERROR const generics in any position are currently unsupported
+    X
+}
+
+fn main() {
+    println!("{:?}", const_u32_identity::<18>());
+}
diff --git a/src/test/ui/const-generics/const-fn-with-const-param.stderr b/src/test/ui/const-generics/const-fn-with-const-param.stderr
new file mode 100644
index 0000000000000..a08ebfb0d9766
--- /dev/null
+++ b/src/test/ui/const-generics/const-fn-with-const-param.stderr
@@ -0,0 +1,24 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-fn-with-const-param.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error: const parameters are not permitted in `const fn`
+  --> $DIR/const-fn-with-const-param.rs:4:1
+   |
+LL | / const fn const_u32_identity<const X: u32>() -> u32 {
+LL | |     //~^ ERROR const parameters are not permitted in `const fn`
+LL | |     //~^^ ERROR const generics in any position are currently unsupported
+LL | |     X
+LL | | }
+   | |_^
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-fn-with-const-param.rs:4:35
+   |
+LL | const fn const_u32_identity<const X: u32>() -> u32 {
+   |                                   ^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/const-generics/const-param-before-other-params.rs b/src/test/ui/const-generics/const-param-before-other-params.rs
new file mode 100644
index 0000000000000..47f826789e03e
--- /dev/null
+++ b/src/test/ui/const-generics/const-param-before-other-params.rs
@@ -0,0 +1,14 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+fn foo<const X: (), T>(_: T) {
+    //~^ ERROR type parameters must be declared prior to const parameters
+    //~^^ ERROR const generics in any position are currently unsupported
+}
+
+fn bar<const X: (), 'a>(_: &'a ()) {
+    //~^ ERROR lifetime parameters must be declared prior to const parameters
+    //~^^ ERROR const generics in any position are currently unsupported
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/const-param-before-other-params.stderr b/src/test/ui/const-generics/const-param-before-other-params.stderr
new file mode 100644
index 0000000000000..a43415d0e5a43
--- /dev/null
+++ b/src/test/ui/const-generics/const-param-before-other-params.stderr
@@ -0,0 +1,32 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-param-before-other-params.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error: type parameters must be declared prior to const parameters
+  --> $DIR/const-param-before-other-params.rs:4:21
+   |
+LL | fn foo<const X: (), T>(_: T) {
+   |       --------------^- help: reorder the parameters: lifetimes, then types, then consts: `<T, const X: ()>`
+
+error: lifetime parameters must be declared prior to const parameters
+  --> $DIR/const-param-before-other-params.rs:9:21
+   |
+LL | fn bar<const X: (), 'a>(_: &'a ()) {
+   |       --------------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, const X: ()>`
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-param-before-other-params.rs:4:14
+   |
+LL | fn foo<const X: (), T>(_: T) {
+   |              ^
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-param-before-other-params.rs:9:14
+   |
+LL | fn bar<const X: (), 'a>(_: &'a ()) {
+   |              ^
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/const-generics/const-param-from-outer-fn.rs b/src/test/ui/const-generics/const-param-from-outer-fn.rs
new file mode 100644
index 0000000000000..5a8dd92086f85
--- /dev/null
+++ b/src/test/ui/const-generics/const-param-from-outer-fn.rs
@@ -0,0 +1,11 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+fn foo<const X: u32>() {
+    //~^ ERROR const generics in any position are currently unsupported
+    fn bar() -> u32 {
+        X //~ ERROR can't use generic parameters from outer function
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/const-param-from-outer-fn.stderr b/src/test/ui/const-generics/const-param-from-outer-fn.stderr
new file mode 100644
index 0000000000000..b238b3a2aa453
--- /dev/null
+++ b/src/test/ui/const-generics/const-param-from-outer-fn.stderr
@@ -0,0 +1,26 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-param-from-outer-fn.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error[E0401]: can't use generic parameters from outer function
+  --> $DIR/const-param-from-outer-fn.rs:7:9
+   |
+LL | fn foo<const X: u32>() {
+   |              - const variable from outer function
+LL |     //~^ ERROR const generics in any position are currently unsupported
+LL |     fn bar() -> u32 {
+   |        --- try adding a local generic parameter in this method instead
+LL |         X //~ ERROR can't use generic parameters from outer function
+   |         ^ use of generic parameter from outer function
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-param-from-outer-fn.rs:4:14
+   |
+LL | fn foo<const X: u32>() {
+   |              ^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0401`.
diff --git a/src/test/ui/const-generics/const-parameter-uppercase-lint.rs b/src/test/ui/const-generics/const-parameter-uppercase-lint.rs
new file mode 100644
index 0000000000000..37fe9af98b3df
--- /dev/null
+++ b/src/test/ui/const-generics/const-parameter-uppercase-lint.rs
@@ -0,0 +1,8 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+#![deny(non_upper_case_globals)]
+
+fn noop<const x: u32>() {
+    //~^ ERROR const generics in any position are currently unsupported
+}
diff --git a/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr b/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr
new file mode 100644
index 0000000000000..9683e91cef30c
--- /dev/null
+++ b/src/test/ui/const-generics/const-parameter-uppercase-lint.stderr
@@ -0,0 +1,19 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/const-parameter-uppercase-lint.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error[E0601]: `main` function not found in crate `const_parameter_uppercase_lint`
+   |
+   = note: consider adding a `main` function to `$DIR/const-parameter-uppercase-lint.rs`
+
+error: const generics in any position are currently unsupported
+  --> $DIR/const-parameter-uppercase-lint.rs:6:15
+   |
+LL | fn noop<const x: u32>() {
+   |               ^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0601`.
diff --git a/src/test/ui/consts/const-eval/const_raw_ptr_ops.rs b/src/test/ui/consts/const-eval/const_raw_ptr_ops.rs
index 63bac17f1c0f3..44266682a5c6c 100644
--- a/src/test/ui/consts/const-eval/const_raw_ptr_ops.rs
+++ b/src/test/ui/consts/const-eval/const_raw_ptr_ops.rs
@@ -3,13 +3,13 @@
 fn main() {}
 
 // unconst and bad, will thus error in miri
-const X: bool = &1 as *const i32 == &2 as *const i32; //~ ERROR any use of this value will cause
+const X: bool = unsafe { &1 as *const i32 == &2 as *const i32 }; //~ ERROR any use of this
 // unconst and fine
-const X2: bool = 42 as *const i32 == 43 as *const i32;
+const X2: bool = unsafe { 42 as *const i32 == 43 as *const i32 };
 // unconst and fine
-const Y: usize = 42usize as *const i32 as usize + 1;
+const Y: usize = unsafe { 42usize as *const i32 as usize + 1 };
 // unconst and bad, will thus error in miri
-const Y2: usize = &1 as *const i32 as usize + 1; //~ ERROR any use of this value will cause
+const Y2: usize = unsafe { &1 as *const i32 as usize + 1 }; //~ ERROR any use of this
 // unconst and fine
 const Z: i32 = unsafe { *(&1 as *const i32) };
 // unconst and bad, will thus error in miri
diff --git a/src/test/ui/consts/const-eval/const_raw_ptr_ops.stderr b/src/test/ui/consts/const-eval/const_raw_ptr_ops.stderr
index ea11359af85ed..6be54c0bad4f9 100644
--- a/src/test/ui/consts/const-eval/const_raw_ptr_ops.stderr
+++ b/src/test/ui/consts/const-eval/const_raw_ptr_ops.stderr
@@ -1,20 +1,20 @@
 error: any use of this value will cause an error
   --> $DIR/const_raw_ptr_ops.rs:6:1
    |
-LL | const X: bool = &1 as *const i32 == &2 as *const i32; //~ ERROR any use of this value will cause
-   | ^^^^^^^^^^^^^^^^------------------------------------^
-   |                 |
-   |                 "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
+LL | const X: bool = unsafe { &1 as *const i32 == &2 as *const i32 }; //~ ERROR any use of this
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^------------------------------------^^^
+   |                          |
+   |                          "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
    |
    = note: #[deny(const_err)] on by default
 
 error: any use of this value will cause an error
   --> $DIR/const_raw_ptr_ops.rs:12:1
    |
-LL | const Y2: usize = &1 as *const i32 as usize + 1; //~ ERROR any use of this value will cause
-   | ^^^^^^^^^^^^^^^^^^-----------------------------^
-   |                   |
-   |                   "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
+LL | const Y2: usize = unsafe { &1 as *const i32 as usize + 1 }; //~ ERROR any use of this
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^-----------------------------^^^
+   |                            |
+   |                            "pointer arithmetic or comparison" needs an rfc before being allowed inside constants
 
 error: any use of this value will cause an error
   --> $DIR/const_raw_ptr_ops.rs:16:1
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.rs b/src/test/ui/consts/const-eval/ub-nonnull.rs
index 7fbcab8245a0f..3e0b0948ef3c3 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.rs
+++ b/src/test/ui/consts/const-eval/ub-nonnull.rs
@@ -13,6 +13,13 @@ const NULL_U8: NonZeroU8 = unsafe { mem::transmute(0u8) };
 const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
 //~^ ERROR it is undefined behavior to use this value
 
+union Transmute {
+    uninit: (),
+    out: NonZeroU8,
+}
+const UNINIT: NonZeroU8 = unsafe { Transmute { uninit: () }.out };
+//~^ ERROR it is undefined behavior to use this value
+
 // Also test other uses of rustc_layout_scalar_valid_range_start
 
 #[rustc_layout_scalar_valid_range_start(10)]
diff --git a/src/test/ui/consts/const-eval/ub-nonnull.stderr b/src/test/ui/consts/const-eval/ub-nonnull.stderr
index 5f8e0c73fbb2a..6230712ad6f23 100644
--- a/src/test/ui/consts/const-eval/ub-nonnull.stderr
+++ b/src/test/ui/consts/const-eval/ub-nonnull.stderr
@@ -23,7 +23,15 @@ LL | const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:21:1
+  --> $DIR/ub-nonnull.rs:20:1
+   |
+LL | const UNINIT: NonZeroU8 = unsafe { Transmute { uninit: () }.out };
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered uninitialized bytes, but expected something greater or equal to 1
+   |
+   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior
+
+error[E0080]: it is undefined behavior to use this value
+  --> $DIR/ub-nonnull.rs:28:1
    |
 LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered 42, but expected something in the range 10..=30
@@ -31,13 +39,13 @@ LL | const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-nonnull.rs:27:1
+  --> $DIR/ub-nonnull.rs:34:1
    |
 LL | const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type validation failed: encountered 20, but expected something less or equal to 10, or greater or equal to 30
    |
    = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0080`.
diff --git a/src/test/ui/consts/const-size_of-cycle.stderr b/src/test/ui/consts/const-size_of-cycle.stderr
index 8f9498e834d8f..8f8eb38e93873 100644
--- a/src/test/ui/consts/const-size_of-cycle.stderr
+++ b/src/test/ui/consts/const-size_of-cycle.stderr
@@ -9,8 +9,8 @@ note: ...which requires const-evaluating `Foo::bytes::{{constant}}`...
    |
 LL |     intrinsics::size_of::<T>()
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires computing layout of `Foo`...
-note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
+   = note: ...which requires computing layout of `Foo`...
+   = note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
 note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}`...
   --> $DIR/const-size_of-cycle.rs:6:17
    |
diff --git a/src/test/ui/consts/drop_none.rs b/src/test/ui/consts/drop_none.rs
new file mode 100644
index 0000000000000..86a197ffb993e
--- /dev/null
+++ b/src/test/ui/consts/drop_none.rs
@@ -0,0 +1,13 @@
+// compile-pass
+#![allow(dead_code)]
+struct A;
+impl Drop for A {
+    fn drop(&mut self) {}
+}
+
+const FOO: Option<A> = None;
+
+const BAR: () = (FOO, ()).1;
+
+
+fn main() {}
diff --git a/src/test/ui/consts/match_ice.rs b/src/test/ui/consts/match_ice.rs
new file mode 100644
index 0000000000000..53c5782a4c70e
--- /dev/null
+++ b/src/test/ui/consts/match_ice.rs
@@ -0,0 +1,10 @@
+// https://github.com/rust-lang/rust/issues/53708
+
+struct S;
+
+fn main() {
+    const C: &S = &S;
+    match C { //~ ERROR non-exhaustive
+        C => {} // this is a common bug around constants and references in patterns
+    }
+}
diff --git a/src/test/ui/consts/match_ice.stderr b/src/test/ui/consts/match_ice.stderr
new file mode 100644
index 0000000000000..e6e04e2c46276
--- /dev/null
+++ b/src/test/ui/consts/match_ice.stderr
@@ -0,0 +1,9 @@
+error[E0004]: non-exhaustive patterns: `&S` not covered
+  --> $DIR/match_ice.rs:7:11
+   |
+LL |     match C { //~ ERROR non-exhaustive
+   |           ^ pattern `&S` not covered
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0004`.
diff --git a/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr b/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr
index f6b704370b6f2..62f678790d21f 100644
--- a/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr
+++ b/src/test/ui/consts/min_const_fn/bad_const_fn_body_ice.stderr
@@ -1,10 +1,12 @@
-error: heap allocations are not allowed in const fn
+error[E0723]: heap allocations are not allowed in const fn (see issue #57563)
   --> $DIR/bad_const_fn_body_ice.rs:2:5
    |
 LL |     vec![1, 2, 3] //~ ERROR heap allocations are not allowed in const fn
    |     ^^^^^^^^^^^^^
    |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/cast_errors.stderr b/src/test/ui/consts/min_const_fn/cast_errors.stderr
index ba980b7aacb6c..b5af3e7ee4665 100644
--- a/src/test/ui/consts/min_const_fn/cast_errors.stderr
+++ b/src/test/ui/consts/min_const_fn/cast_errors.stderr
@@ -1,32 +1,43 @@
-error: unsizing casts are not allowed in const fn
+error[E0723]: unsizing casts are not allowed in const fn (see issue #57563)
   --> $DIR/cast_errors.rs:3:41
    |
 LL | const fn unsize(x: &[u8; 3]) -> &[u8] { x }
    |                                         ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/cast_errors.rs:5:23
    |
 LL | const fn closure() -> fn() { || {} }
    |                       ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/cast_errors.rs:8:5
    |
 LL |     (|| {}) as fn();
    |     ^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/cast_errors.rs:11:28
    |
 LL | const fn reify(f: fn()) -> unsafe fn() { f }
    |                            ^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/cast_errors.rs:13:21
    |
 LL | const fn reify2() { main as unsafe fn(); }
    |                     ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 5 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/cmp_fn_pointers.rs b/src/test/ui/consts/min_const_fn/cmp_fn_pointers.rs
index d8abd97655805..c2600f894dc42 100644
--- a/src/test/ui/consts/min_const_fn/cmp_fn_pointers.rs
+++ b/src/test/ui/consts/min_const_fn/cmp_fn_pointers.rs
@@ -1,5 +1,5 @@
 const fn cmp(x: fn(), y: fn()) -> bool { //~ ERROR function pointers in const fn are unstable
-    x == y
+    unsafe { x == y }
 }
 
 fn main() {}
diff --git a/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr b/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr
index a050c10e02cf9..d84e2651d4fc4 100644
--- a/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr
+++ b/src/test/ui/consts/min_const_fn/cmp_fn_pointers.stderr
@@ -1,8 +1,11 @@
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/cmp_fn_pointers.rs:1:14
    |
 LL | const fn cmp(x: fn(), y: fn()) -> bool { //~ ERROR function pointers in const fn are unstable
    |              ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/loop_ice.stderr b/src/test/ui/consts/min_const_fn/loop_ice.stderr
index 1424cea65afd5..716e8380c45da 100644
--- a/src/test/ui/consts/min_const_fn/loop_ice.stderr
+++ b/src/test/ui/consts/min_const_fn/loop_ice.stderr
@@ -1,8 +1,11 @@
-error: loops are not allowed in const fn
+error[E0723]: loops are not allowed in const fn (see issue #57563)
   --> $DIR/loop_ice.rs:2:5
    |
 LL |     loop {} //~ ERROR loops are not allowed in const fn
    |     ^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.nll.stderr b/src/test/ui/consts/min_const_fn/min_const_fn.nll.stderr
index 91b076097b018..feb4960e0c746 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.nll.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.nll.stderr
@@ -4,11 +4,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner(self) -> T { self.0 } //~ destructors cannot be evaluated
    |                         ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:39:36
    |
 LL |     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
    |                                    ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error[E0493]: destructors cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:44:28
@@ -16,11 +18,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_lt(self) -> T { self.0 } //~ destructors cannot be evaluated
    |                            ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:46:42
    |
 LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
    |                                          ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error[E0493]: destructors cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:51:27
@@ -28,164 +32,232 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_s(self) -> T { self.0 } //~ ERROR destructors
    |                           ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:53:38
    |
 LL |     const fn get_mut_s(&mut self) -> &mut T { &mut self.0 }
    |                                      ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:58:39
    |
 LL |     const fn get_mut_sq(&mut self) -> &mut T { &mut self.0 }
    |                                       ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:76:16
    |
 LL | const fn foo11<T: std::fmt::Display>(t: T) -> T { t }
    |                ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:78:18
    |
 LL | const fn foo11_2<T: Send>(t: T) -> T { t }
    |                  ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:80:33
    |
 LL | const fn foo19(f: f32) -> f32 { f * 2.0 }
    |                                 ^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:82:35
    |
 LL | const fn foo19_2(f: f32) -> f32 { 2.0 - f }
    |                                   ^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int and `bool` operations are stable in const fn
+error[E0723]: only int and `bool` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:84:35
    |
 LL | const fn foo19_3(f: f32) -> f32 { -f }
    |                                   ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:86:43
    |
 LL | const fn foo19_4(f: f32, g: f32) -> f32 { f / g }
    |                                           ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: cannot access `static` items in const fn
+error[E0723]: cannot access `static` items in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:90:27
    |
 LL | const fn foo25() -> u32 { BAR } //~ ERROR cannot access `static` items in const fn
    |                           ^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: cannot access `static` items in const fn
+error[E0723]: cannot access `static` items in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:91:36
    |
 LL | const fn foo26() -> &'static u32 { &BAR } //~ ERROR cannot access `static` items
    |                                    ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: casting pointers to ints is unstable in const fn
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:92:42
    |
 LL | const fn foo30(x: *const u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: casting pointers to ints is unstable in const fn
-  --> $DIR/min_const_fn.rs:94:42
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:94:63
+   |
+LL | const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
+   |                                                               ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
+
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:96:42
    |
 LL | const fn foo30_2(x: *mut u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:96:38
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:98:63
+   |
+LL | const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
+   |                                                               ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
+
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:100:38
    |
 LL | const fn foo30_4(b: bool) -> usize { if b { 1 } else { 42 } }
    |                                      ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:98:29
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:102:29
    |
 LL | const fn foo30_5(b: bool) { while b { } } //~ ERROR not stable in const fn
    |                             ^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:100:44
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:104:44
    |
 LL | const fn foo36(a: bool, b: bool) -> bool { a && b }
    |                                            ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:102:44
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:106:44
    |
 LL | const fn foo37(a: bool, b: bool) -> bool { a || b }
    |                                            ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
-  --> $DIR/min_const_fn.rs:104:14
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:108:14
    |
 LL | const fn inc(x: &mut i32) { *x += 1 }
    |              ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:109:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:113:6
    |
 LL | impl<T: std::fmt::Debug> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:114:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:118:6
    |
 LL | impl<T: std::fmt::Debug + Sized> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:119:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:123:6
    |
 LL | impl<T: Sync + Sized> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `impl Trait` in const fn is unstable
-  --> $DIR/min_const_fn.rs:125:24
+error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:129:24
    |
 LL | const fn no_rpit2() -> AlanTuring<impl std::fmt::Debug> { AlanTuring(0) }
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:127:34
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:131:34
    |
 LL | const fn no_apit2(_x: AlanTuring<impl std::fmt::Debug>) {}
    |                                  ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:129:22
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:133:22
    |
 LL | const fn no_apit(_x: impl std::fmt::Debug) {} //~ ERROR trait bounds other than `Sized`
    |                      ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `impl Trait` in const fn is unstable
-  --> $DIR/min_const_fn.rs:130:23
+error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:134:23
    |
 LL | const fn no_rpit() -> impl std::fmt::Debug {} //~ ERROR `impl Trait` in const fn is unstable
    |                       ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:131:23
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:135:23
    |
 LL | const fn no_dyn_trait(_x: &dyn std::fmt::Debug) {} //~ ERROR trait bounds other than `Sized`
    |                       ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:132:32
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:136:32
    |
 LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 warning[E0515]: cannot return reference to temporary value
-  --> $DIR/min_const_fn.rs:132:63
+  --> $DIR/min_const_fn.rs:136:63
    |
 LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
    |                                                               ^--
@@ -196,25 +268,31 @@ LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
    = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
    = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:137:41
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:141:41
    |
 LL | const fn really_no_traits_i_mean_it() { (&() as &std::fmt::Debug, ()).1 }
    |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
-  --> $DIR/min_const_fn.rs:140:21
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:144:21
    |
 LL | const fn no_fn_ptrs(_x: fn()) {}
    |                     ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
-  --> $DIR/min_const_fn.rs:142:27
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:146:27
    |
 LL | const fn no_fn_ptrs2() -> fn() { fn foo() {} foo }
    |                           ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: aborting due to 34 previous errors
+error: aborting due to 36 previous errors
 
-Some errors occurred: E0493, E0515.
+Some errors occurred: E0493, E0515, E0723.
 For more information about an error, try `rustc --explain E0493`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.rs b/src/test/ui/consts/min_const_fn/min_const_fn.rs
index 05cf3d5f1f173..ee3ffcd4026d3 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.rs
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.rs
@@ -90,9 +90,13 @@ static BAR: u32 = 42;
 const fn foo25() -> u32 { BAR } //~ ERROR cannot access `static` items in const fn
 const fn foo26() -> &'static u32 { &BAR } //~ ERROR cannot access `static` items
 const fn foo30(x: *const u32) -> usize { x as usize }
-//~^ ERROR casting pointers to int
+//~^ ERROR casting pointers to ints is unstable
+const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
+//~^ ERROR casting pointers to ints is unstable
 const fn foo30_2(x: *mut u32) -> usize { x as usize }
-//~^ ERROR casting pointers to int
+//~^ ERROR casting pointers to ints is unstable
+const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
+//~^ ERROR casting pointers to ints is unstable
 const fn foo30_4(b: bool) -> usize { if b { 1 } else { 42 } }
 //~^ ERROR `if`, `match`, `&&` and `||` are not stable in const fn
 const fn foo30_5(b: bool) { while b { } } //~ ERROR not stable in const fn
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
index 2cae714fbf727..e095ccaf20e29 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn.stderr
@@ -4,11 +4,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner(self) -> T { self.0 } //~ destructors cannot be evaluated
    |                         ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:39:36
    |
 LL |     const fn get_mut(&mut self) -> &mut T { &mut self.0 }
    |                                    ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error[E0493]: destructors cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:44:28
@@ -16,11 +18,13 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_lt(self) -> T { self.0 } //~ destructors cannot be evaluated
    |                            ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:46:42
    |
 LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
    |                                          ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error[E0493]: destructors cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:51:27
@@ -28,180 +32,255 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     const fn into_inner_s(self) -> T { self.0 } //~ ERROR destructors
    |                           ^^^^ constant functions cannot evaluate destructors
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:53:38
    |
 LL |     const fn get_mut_s(&mut self) -> &mut T { &mut self.0 }
    |                                      ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:58:39
    |
 LL |     const fn get_mut_sq(&mut self) -> &mut T { &mut self.0 }
    |                                       ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:76:16
    |
 LL | const fn foo11<T: std::fmt::Display>(t: T) -> T { t }
    |                ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn.rs:78:18
    |
 LL | const fn foo11_2<T: Send>(t: T) -> T { t }
    |                  ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:80:33
    |
 LL | const fn foo19(f: f32) -> f32 { f * 2.0 }
    |                                 ^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:82:35
    |
 LL | const fn foo19_2(f: f32) -> f32 { 2.0 - f }
    |                                   ^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int and `bool` operations are stable in const fn
+error[E0723]: only int and `bool` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:84:35
    |
 LL | const fn foo19_3(f: f32) -> f32 { -f }
    |                                   ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:86:43
    |
 LL | const fn foo19_4(f: f32, g: f32) -> f32 { f / g }
    |                                           ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: cannot access `static` items in const fn
+error[E0723]: cannot access `static` items in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:90:27
    |
 LL | const fn foo25() -> u32 { BAR } //~ ERROR cannot access `static` items in const fn
    |                           ^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: cannot access `static` items in const fn
+error[E0723]: cannot access `static` items in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:91:36
    |
 LL | const fn foo26() -> &'static u32 { &BAR } //~ ERROR cannot access `static` items
    |                                    ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: casting pointers to ints is unstable in const fn
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
   --> $DIR/min_const_fn.rs:92:42
    |
 LL | const fn foo30(x: *const u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: casting pointers to ints is unstable in const fn
-  --> $DIR/min_const_fn.rs:94:42
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:94:63
+   |
+LL | const fn foo30_with_unsafe(x: *const u32) -> usize { unsafe { x as usize } }
+   |                                                               ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
+
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:96:42
    |
 LL | const fn foo30_2(x: *mut u32) -> usize { x as usize }
    |                                          ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:96:38
+error[E0723]: casting pointers to ints is unstable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:98:63
+   |
+LL | const fn foo30_2_with_unsafe(x: *mut u32) -> usize { unsafe { x as usize } }
+   |                                                               ^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
+
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:100:38
    |
 LL | const fn foo30_4(b: bool) -> usize { if b { 1 } else { 42 } }
    |                                      ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:98:29
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:102:29
    |
 LL | const fn foo30_5(b: bool) { while b { } } //~ ERROR not stable in const fn
    |                             ^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:100:44
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:104:44
    |
 LL | const fn foo36(a: bool, b: bool) -> bool { a && b }
    |                                            ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
-  --> $DIR/min_const_fn.rs:102:44
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
+  --> $DIR/min_const_fn.rs:106:44
    |
 LL | const fn foo37(a: bool, b: bool) -> bool { a || b }
    |                                            ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
-  --> $DIR/min_const_fn.rs:104:14
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:108:14
    |
 LL | const fn inc(x: &mut i32) { *x += 1 }
    |              ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:109:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:113:6
    |
 LL | impl<T: std::fmt::Debug> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:114:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:118:6
    |
 LL | impl<T: std::fmt::Debug + Sized> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:119:6
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:123:6
    |
 LL | impl<T: Sync + Sized> Foo<T> {
    |      ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `impl Trait` in const fn is unstable
-  --> $DIR/min_const_fn.rs:125:24
+error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:129:24
    |
 LL | const fn no_rpit2() -> AlanTuring<impl std::fmt::Debug> { AlanTuring(0) }
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:127:34
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:131:34
    |
 LL | const fn no_apit2(_x: AlanTuring<impl std::fmt::Debug>) {}
    |                                  ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:129:22
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:133:22
    |
 LL | const fn no_apit(_x: impl std::fmt::Debug) {} //~ ERROR trait bounds other than `Sized`
    |                      ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: `impl Trait` in const fn is unstable
-  --> $DIR/min_const_fn.rs:130:23
+error[E0723]: `impl Trait` in const fn is unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:134:23
    |
 LL | const fn no_rpit() -> impl std::fmt::Debug {} //~ ERROR `impl Trait` in const fn is unstable
    |                       ^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:131:23
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:135:23
    |
 LL | const fn no_dyn_trait(_x: &dyn std::fmt::Debug) {} //~ ERROR trait bounds other than `Sized`
    |                       ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:132:32
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:136:32
    |
 LL | const fn no_dyn_trait_ret() -> &'static dyn std::fmt::Debug { &() }
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
-  --> $DIR/min_const_fn.rs:137:41
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:141:41
    |
 LL | const fn really_no_traits_i_mean_it() { (&() as &std::fmt::Debug, ()).1 }
    |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
-  --> $DIR/min_const_fn.rs:140:21
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:144:21
    |
 LL | const fn no_fn_ptrs(_x: fn()) {}
    |                     ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
-  --> $DIR/min_const_fn.rs:142:27
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
+  --> $DIR/min_const_fn.rs:146:27
    |
 LL | const fn no_fn_ptrs2() -> fn() { fn foo() {} foo }
    |                           ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: aborting due to 34 previous errors
+error: aborting due to 36 previous errors
 
-For more information about this error, try `rustc --explain E0493`.
+Some errors occurred: E0493, E0723.
+For more information about an error, try `rustc --explain E0493`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.nll.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.nll.stderr
index 6dbe9b1c6ab10..2800d622f5353 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.nll.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.nll.stderr
@@ -1,14 +1,18 @@
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn_dyn.rs:9:5
    |
 LL |     x.0.field;
    |     ^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn_dyn.rs:12:66
    |
 LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasDyn { field: &0 }) }
    |                                                                  ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 warning[E0716]: temporary value dropped while borrowed
   --> $DIR/min_const_fn_dyn.rs:12:67
@@ -24,4 +28,5 @@ LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasDyn { field: &0 }) }
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0716`.
+Some errors occurred: E0716, E0723.
+For more information about an error, try `rustc --explain E0716`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr
index 8179cf795b48c..8ff963722cf15 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_dyn.stderr
@@ -1,14 +1,19 @@
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn_dyn.rs:9:5
    |
 LL |     x.0.field;
    |     ^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: trait bounds other than `Sized` on const fn parameters are unstable
+error[E0723]: trait bounds other than `Sized` on const fn parameters are unstable (see issue #57563)
   --> $DIR/min_const_fn_dyn.rs:12:66
    |
 LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasDyn { field: &0 }) }
    |                                                                  ^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr
index c1cb19180a5ee..8838ababe2c0e 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_fn_ptr.stderr
@@ -1,14 +1,19 @@
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn_fn_ptr.rs:11:5
    |
 LL |     x.0.field;
    |     ^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/min_const_fn_fn_ptr.rs:14:59
    |
 LL | const fn no_inner_dyn_trait_ret() -> Hide { Hide(HasPtr { field }) }
    |                                                           ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr
index 9640105d25c54..1e6f698b3c8e3 100644
--- a/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_fn_libstd_stability.stderr
@@ -1,26 +1,35 @@
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_fn_libstd_stability.rs:15:25
    |
 LL | const fn bar() -> u32 { foo() } //~ ERROR can only call other `min_const_fn`
    |                         ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_fn_libstd_stability.rs:22:26
    |
 LL | const fn bar2() -> u32 { foo2() } //~ ERROR can only call other `min_const_fn`
    |                          ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_fn_libstd_stability.rs:26:26
    |
 LL | const fn bar3() -> u32 { (5f32 + 6f32) as u32 } //~ ERROR only int, `bool` and `char` operations
    |                          ^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_fn_libstd_stability.rs:34:32
    |
 LL | const fn bar2_gated() -> u32 { foo2_gated() } //~ ERROR can only call other `min_const_fn`
    |                                ^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr
index 049c25e71913d..07d10984392d8 100644
--- a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability.stderr
@@ -1,26 +1,35 @@
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability.rs:15:41
    |
 LL | const unsafe fn bar() -> u32 { unsafe { foo() } } //~ ERROR can only call other `min_const_fn`
    |                                         ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability.rs:22:42
    |
 LL | const unsafe fn bar2() -> u32 { unsafe { foo2() } } //~ ERROR can only call other `min_const_fn`
    |                                          ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: only int, `bool` and `char` operations are stable in const fn
+error[E0723]: only int, `bool` and `char` operations are stable in const fn (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability.rs:26:33
    |
 LL | const unsafe fn bar3() -> u32 { (5f32 + 6f32) as u32 } //~ ERROR only int, `bool` and `char` op
    |                                 ^^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability.rs:34:48
    |
 LL | const unsafe fn bar2_gated() -> u32 { unsafe { foo2_gated() } } //~ ERROR can only call other
    |                                                ^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 4 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr
index 89509f813e107..7cb8c6e62ec60 100644
--- a/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr
+++ b/src/test/ui/consts/min_const_fn/min_const_unsafe_fn_libstd_stability2.stderr
@@ -1,20 +1,27 @@
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:15:32
    |
 LL | const unsafe fn bar() -> u32 { foo() } //~ ERROR can only call other `min_const_fn`
    |                                ^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:22:33
    |
 LL | const unsafe fn bar2() -> u32 { foo2() } //~ ERROR can only call other `min_const_fn`
    |                                 ^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: can only call other `min_const_fn` within a `min_const_fn`
+error[E0723]: can only call other `min_const_fn` within a `min_const_fn` (see issue #57563)
   --> $DIR/min_const_unsafe_fn_libstd_stability2.rs:30:39
    |
 LL | const unsafe fn bar2_gated() -> u32 { foo2_gated() } //~ ERROR can only call other `min_const_fn`
    |                                       ^^^^^^^^^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/min_const_fn/mutable_borrow.stderr b/src/test/ui/consts/min_const_fn/mutable_borrow.stderr
index 5ce0f30dc6e1f..e5a3502a3dc52 100644
--- a/src/test/ui/consts/min_const_fn/mutable_borrow.stderr
+++ b/src/test/ui/consts/min_const_fn/mutable_borrow.stderr
@@ -1,14 +1,19 @@
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/mutable_borrow.rs:3:9
    |
 LL |     let b = &mut a; //~ ERROR mutable references in const fn
    |         ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/mutable_borrow.rs:12:13
    |
 LL |         let b = &mut a; //~ ERROR mutable references in const fn
    |             ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/consts/miri_unleashed/assoc_const.rs b/src/test/ui/consts/miri_unleashed/assoc_const.rs
new file mode 100644
index 0000000000000..b8959667cc215
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/assoc_const.rs
@@ -0,0 +1,30 @@
+// compile-flags: -Zunleash-the-miri-inside-of-you
+#![allow(const_err)]
+
+// a test demonstrating why we do need to run static const qualification on associated constants
+// instead of just checking the final constant
+
+trait Foo<T> {
+    const X: T;
+}
+
+trait Bar<T, U: Foo<T>> {
+    const F: u32 = (U::X, 42).1; //~ WARN skipping const checks
+}
+
+impl Foo<u32> for () {
+    const X: u32 = 42;
+}
+impl Foo<Vec<u32>> for String {
+    const X: Vec<u32> = Vec::new();
+}
+
+impl Bar<u32, ()> for () {}
+impl Bar<Vec<u32>, String> for String {}
+
+fn main() {
+    // this is fine, but would have been forbidden by the static checks on `F`
+    let x = <() as Bar<u32, ()>>::F;
+    // this test only causes errors due to the line below, so post-monomorphization
+    let y = <String as Bar<Vec<u32>, String>>::F; //~ ERROR erroneous constant
+}
diff --git a/src/test/ui/consts/miri_unleashed/assoc_const.stderr b/src/test/ui/consts/miri_unleashed/assoc_const.stderr
new file mode 100644
index 0000000000000..a40f8d46d0aa7
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/assoc_const.stderr
@@ -0,0 +1,15 @@
+warning: skipping const checks
+  --> $DIR/assoc_const.rs:12:31
+   |
+LL |     const F: u32 = (U::X, 42).1; //~ WARN skipping const checks
+   |                               ^
+
+error[E0080]: erroneous constant used
+  --> $DIR/assoc_const.rs:29:13
+   |
+LL |     let y = <String as Bar<Vec<u32>, String>>::F; //~ ERROR erroneous constant
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/src/test/ui/consts/miri_unleashed/assoc_const_2.rs b/src/test/ui/consts/miri_unleashed/assoc_const_2.rs
new file mode 100644
index 0000000000000..c87b6389848f4
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/assoc_const_2.rs
@@ -0,0 +1,28 @@
+#![allow(const_err)]
+
+// a test demonstrating that const qualification cannot prevent monomorphization time errors
+
+trait Foo {
+    const X: u32;
+}
+
+trait Bar<U: Foo> {
+    const F: u32 = 100 / U::X;
+}
+
+impl Foo for () {
+    const X: u32 = 42;
+}
+
+impl Foo for String {
+    const X: u32 = 0;
+}
+
+impl Bar<()> for () {}
+impl Bar<String> for String {}
+
+fn main() {
+    let x = <() as Bar<()>>::F;
+    // this test only causes errors due to the line below, so post-monomorphization
+    let y = <String as Bar<String>>::F; //~ ERROR erroneous constant
+}
diff --git a/src/test/ui/consts/miri_unleashed/assoc_const_2.stderr b/src/test/ui/consts/miri_unleashed/assoc_const_2.stderr
new file mode 100644
index 0000000000000..77aab31d26ec3
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/assoc_const_2.stderr
@@ -0,0 +1,9 @@
+error[E0080]: erroneous constant used
+  --> $DIR/assoc_const_2.rs:27:13
+   |
+LL |     let y = <String as Bar<String>>::F; //~ ERROR erroneous constant
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ referenced constant has errors
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs
new file mode 100644
index 0000000000000..5fb92535502a5
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.rs
@@ -0,0 +1,27 @@
+#![allow(const_err)]
+
+// a test demonstrating why we do need to run static const qualification on associated constants
+// instead of just checking the final constant
+
+trait Foo<T> {
+    const X: T;
+}
+
+trait Bar<T, U: Foo<T>> {
+    const F: u32 = (U::X, 42).1; //~ ERROR destructors cannot be evaluated at compile-time
+}
+
+impl Foo<u32> for () {
+    const X: u32 = 42;
+}
+impl Foo<Vec<u32>> for String {
+    const X: Vec<u32> = Vec::new(); //~ ERROR not yet stable as a const fn
+}
+
+impl Bar<u32, ()> for () {}
+impl Bar<Vec<u32>, String> for String {}
+
+fn main() {
+    let x = <() as Bar<u32, ()>>::F;
+    let y = <String as Bar<Vec<u32>, String>>::F;
+}
diff --git a/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr
new file mode 100644
index 0000000000000..e23ed1c620639
--- /dev/null
+++ b/src/test/ui/consts/miri_unleashed/feature-gate-unleash_the_miri_inside_of_you.stderr
@@ -0,0 +1,17 @@
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/feature-gate-unleash_the_miri_inside_of_you.rs:11:20
+   |
+LL |     const F: u32 = (U::X, 42).1; //~ ERROR destructors cannot be evaluated at compile-time
+   |                    ^^^^^^^^^^ constants cannot evaluate destructors
+
+error: `<std::vec::Vec<T>>::new` is not yet stable as a const fn
+  --> $DIR/feature-gate-unleash_the_miri_inside_of_you.rs:18:25
+   |
+LL |     const X: Vec<u32> = Vec::new(); //~ ERROR not yet stable as a const fn
+   |                         ^^^^^^^^^^
+   |
+   = help: add `#![feature(const_vec_new)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0493`.
diff --git a/src/test/ui/consts/promote_evaluation_unused_result.rs b/src/test/ui/consts/promote_evaluation_unused_result.rs
new file mode 100644
index 0000000000000..d199e34775e4b
--- /dev/null
+++ b/src/test/ui/consts/promote_evaluation_unused_result.rs
@@ -0,0 +1,8 @@
+//compile-pass
+
+#![feature(nll)]
+
+fn main() {
+
+    let _: &'static usize = &(loop {}, 1).1;
+}
diff --git a/src/test/ui/consts/single_variant_match_ice.stderr b/src/test/ui/consts/single_variant_match_ice.stderr
index f5c2cb5e0e9dc..5272062ccfc14 100644
--- a/src/test/ui/consts/single_variant_match_ice.stderr
+++ b/src/test/ui/consts/single_variant_match_ice.stderr
@@ -10,12 +10,15 @@ error[E0019]: constant contains unimplemented expression type
 LL |     x => 42, //~ ERROR unimplemented expression type
    |     ^
 
-error: `if`, `match`, `&&` and `||` are not stable in const fn
+error[E0723]: `if`, `match`, `&&` and `||` are not stable in const fn (see issue #57563)
   --> $DIR/single_variant_match_ice.rs:18:13
    |
 LL |             Prob => 0x1, //~ ERROR `if`, `match`, `&&` and `||` are not stable in const fn
    |             ^^^^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0019`.
+Some errors occurred: E0019, E0723.
+For more information about an error, try `rustc --explain E0019`.
diff --git a/src/test/ui/deprecation/atomic_initializers.fixed b/src/test/ui/deprecation/atomic_initializers.fixed
new file mode 100644
index 0000000000000..dee1d979cff1d
--- /dev/null
+++ b/src/test/ui/deprecation/atomic_initializers.fixed
@@ -0,0 +1,11 @@
+// run-rustfix
+// compile-pass
+
+#[allow(deprecated, unused_imports)]
+use std::sync::atomic::{AtomicIsize, ATOMIC_ISIZE_INIT};
+
+#[allow(dead_code)]
+static FOO: AtomicIsize = AtomicIsize::new(0);
+//~^ WARN use of deprecated item
+
+fn main() {}
diff --git a/src/test/ui/deprecation/atomic_initializers.rs b/src/test/ui/deprecation/atomic_initializers.rs
new file mode 100644
index 0000000000000..b9e25e817bce4
--- /dev/null
+++ b/src/test/ui/deprecation/atomic_initializers.rs
@@ -0,0 +1,11 @@
+// run-rustfix
+// compile-pass
+
+#[allow(deprecated, unused_imports)]
+use std::sync::atomic::{AtomicIsize, ATOMIC_ISIZE_INIT};
+
+#[allow(dead_code)]
+static FOO: AtomicIsize = ATOMIC_ISIZE_INIT;
+//~^ WARN use of deprecated item
+
+fn main() {}
diff --git a/src/test/ui/deprecation/atomic_initializers.stderr b/src/test/ui/deprecation/atomic_initializers.stderr
new file mode 100644
index 0000000000000..77c370814f7af
--- /dev/null
+++ b/src/test/ui/deprecation/atomic_initializers.stderr
@@ -0,0 +1,12 @@
+warning: use of deprecated item 'std::sync::atomic::ATOMIC_ISIZE_INIT': the `new` function is now preferred
+  --> $DIR/atomic_initializers.rs:8:27
+   |
+LL | static FOO: AtomicIsize = ATOMIC_ISIZE_INIT;
+   |                           ^^^^^^^^^^^^^^^^^
+   |
+   = note: #[warn(deprecated)] on by default
+help: use of deprecated item 'std::sync::atomic::ATOMIC_ISIZE_INIT': the `new` function is now preferred
+   |
+LL | static FOO: AtomicIsize = AtomicIsize::new(0);
+   |                           ^^^^^^^^^^^^^^^^^^^
+
diff --git a/src/test/ui/deprecation/deprecation-in-future.rs b/src/test/ui/deprecation/deprecation-in-future.rs
index c6c60177e9d0e..138d902621cbc 100644
--- a/src/test/ui/deprecation/deprecation-in-future.rs
+++ b/src/test/ui/deprecation/deprecation-in-future.rs
@@ -1,12 +1,14 @@
 // ignore-tidy-linelength
 
+// run-pass
+
 #![deny(deprecated_in_future)]
 
 #[deprecated(since = "99.99.99", note = "text")]
 pub fn deprecated_future() {}
 
 fn test() {
-    deprecated_future(); //~ ERROR use of item 'deprecated_future' that will be deprecated in future version 99.99.99: text
+    deprecated_future(); // ok; deprecated_in_future only applies to rustc_deprecated
 }
 
 fn main() {}
diff --git a/src/test/ui/deprecation/deprecation-in-future.stderr b/src/test/ui/deprecation/deprecation-in-future.stderr
index 38392cf96084c..81d2461c1bd83 100644
--- a/src/test/ui/deprecation/deprecation-in-future.stderr
+++ b/src/test/ui/deprecation/deprecation-in-future.stderr
@@ -1,14 +1,8 @@
-error: use of item 'deprecated_future' that will be deprecated in future version 99.99.99: text
-  --> $DIR/deprecation-in-future.rs:9:5
+warning: use of deprecated item 'deprecated_future': text
+  --> $DIR/deprecation-in-future.rs:11:5
    |
-LL |     deprecated_future(); //~ ERROR use of item 'deprecated_future' that will be deprecated in future version 99.99.99: text
+LL |     deprecated_future(); // ok; deprecated_in_future only applies to rustc_deprecated
    |     ^^^^^^^^^^^^^^^^^
    |
-note: lint level defined here
-  --> $DIR/deprecation-in-future.rs:3:9
-   |
-LL | #![deny(deprecated_in_future)]
-   |         ^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to previous error
+   = note: #[warn(deprecated)] on by default
 
diff --git a/src/test/ui/deprecation/deprecation-lint.rs b/src/test/ui/deprecation/deprecation-lint.rs
index 6b3e9a8ad8116..033d6eebbb219 100644
--- a/src/test/ui/deprecation/deprecation-lint.rs
+++ b/src/test/ui/deprecation/deprecation-lint.rs
@@ -261,8 +261,9 @@ mod this_crate {
         <Foo>::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
         <Foo as Trait>::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
 
-        deprecated_future(); // Fine; no error.
-        deprecated_future_text(); // Fine; no error.
+        // Future deprecations are only permitted for rustc_deprecated.
+        deprecated_future(); //~ ERROR use of deprecated item
+        deprecated_future_text(); //~ ERROR use of deprecated item
 
         let _ = DeprecatedStruct {
             //~^ ERROR use of deprecated item 'this_crate::DeprecatedStruct': text
diff --git a/src/test/ui/deprecation/deprecation-lint.stderr b/src/test/ui/deprecation/deprecation-lint.stderr
index 46875d0bf13ba..c48d06e86154d 100644
--- a/src/test/ui/deprecation/deprecation-lint.stderr
+++ b/src/test/ui/deprecation/deprecation-lint.stderr
@@ -214,128 +214,140 @@ error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
 LL |         <Foo as Trait>::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error: use of deprecated item 'this_crate::deprecated_future': text
+  --> $DIR/deprecation-lint.rs:265:9
+   |
+LL |         deprecated_future(); //~ ERROR use of deprecated item
+   |         ^^^^^^^^^^^^^^^^^
+
+error: use of deprecated item 'this_crate::deprecated_future_text': text
+  --> $DIR/deprecation-lint.rs:266:9
+   |
+LL |         deprecated_future_text(); //~ ERROR use of deprecated item
+   |         ^^^^^^^^^^^^^^^^^^^^^^
+
 error: use of deprecated item 'this_crate::DeprecatedStruct': text
-  --> $DIR/deprecation-lint.rs:267:17
+  --> $DIR/deprecation-lint.rs:268:17
    |
 LL |         let _ = DeprecatedStruct {
    |                 ^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::DeprecatedUnitStruct': text
-  --> $DIR/deprecation-lint.rs:272:17
+  --> $DIR/deprecation-lint.rs:273:17
    |
 LL |         let _ = DeprecatedUnitStruct; //~ ERROR use of deprecated item 'this_crate::DeprecatedUnitStruct': text
    |                 ^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Enum::DeprecatedVariant': text
-  --> $DIR/deprecation-lint.rs:274:17
+  --> $DIR/deprecation-lint.rs:275:17
    |
 LL |         let _ = Enum::DeprecatedVariant; //~ ERROR use of deprecated item 'this_crate::Enum::DeprecatedVariant': text
    |                 ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::DeprecatedTupleStruct': text
-  --> $DIR/deprecation-lint.rs:276:17
+  --> $DIR/deprecation-lint.rs:277:17
    |
 LL |         let _ = DeprecatedTupleStruct (1); //~ ERROR use of deprecated item 'this_crate::DeprecatedTupleStruct': text
    |                 ^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::nested::DeprecatedStruct': text
-  --> $DIR/deprecation-lint.rs:278:17
+  --> $DIR/deprecation-lint.rs:279:17
    |
 LL |         let _ = nested::DeprecatedStruct {
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::nested::DeprecatedUnitStruct': text
-  --> $DIR/deprecation-lint.rs:283:17
+  --> $DIR/deprecation-lint.rs:284:17
    |
 LL |         let _ = nested::DeprecatedUnitStruct; //~ ERROR use of deprecated item 'this_crate::nested::DeprecatedUnitStruct': text
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::nested::Enum::DeprecatedVariant': text
-  --> $DIR/deprecation-lint.rs:285:17
+  --> $DIR/deprecation-lint.rs:286:17
    |
 LL |         let _ = nested::Enum::DeprecatedVariant; //~ ERROR use of deprecated item 'this_crate::nested::Enum::DeprecatedVariant': text
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::nested::DeprecatedTupleStruct': text
-  --> $DIR/deprecation-lint.rs:287:17
+  --> $DIR/deprecation-lint.rs:288:17
    |
 LL |         let _ = nested::DeprecatedTupleStruct (1); //~ ERROR use of deprecated item 'this_crate::nested::DeprecatedTupleStruct': text
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated': text
-  --> $DIR/deprecation-lint.rs:292:9
+  --> $DIR/deprecation-lint.rs:293:9
    |
 LL |         Trait::trait_deprecated(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated'
    |         ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated': text
-  --> $DIR/deprecation-lint.rs:294:9
+  --> $DIR/deprecation-lint.rs:295:9
    |
 LL |         <Foo as Trait>::trait_deprecated(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated'
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
-  --> $DIR/deprecation-lint.rs:296:9
+  --> $DIR/deprecation-lint.rs:297:9
    |
 LL |         Trait::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
-  --> $DIR/deprecation-lint.rs:298:9
+  --> $DIR/deprecation-lint.rs:299:9
    |
 LL |         <Foo as Trait>::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::test_fn_closure_body::{{closure}}::bar'
-  --> $DIR/deprecation-lint.rs:316:13
+  --> $DIR/deprecation-lint.rs:317:13
    |
 LL |             bar(); //~ ERROR use of deprecated item 'this_crate::test_fn_closure_body::{{closure}}::bar'
    |             ^^^
 
 error: use of deprecated item 'this_crate::DeprecatedTrait': text
-  --> $DIR/deprecation-lint.rs:335:10
+  --> $DIR/deprecation-lint.rs:336:10
    |
 LL |     impl DeprecatedTrait for S { } //~ ERROR use of deprecated item 'this_crate::DeprecatedTrait': text
    |          ^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::DeprecatedTrait': text
-  --> $DIR/deprecation-lint.rs:337:24
+  --> $DIR/deprecation-lint.rs:338:24
    |
 LL |     trait LocalTrait : DeprecatedTrait { } //~ ERROR use of deprecated item 'this_crate::DeprecatedTrait': text
    |                        ^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated': text
-  --> $DIR/deprecation-lint.rs:389:17
+  --> $DIR/deprecation-lint.rs:390:17
    |
 LL |         let x = Deprecated {
    |                 ^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated': text
-  --> $DIR/deprecation-lint.rs:398:13
+  --> $DIR/deprecation-lint.rs:399:13
    |
 LL |         let Deprecated {
    |             ^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated': text
-  --> $DIR/deprecation-lint.rs:404:13
+  --> $DIR/deprecation-lint.rs:405:13
    |
 LL |         let Deprecated
    |             ^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2': text
-  --> $DIR/deprecation-lint.rs:409:17
+  --> $DIR/deprecation-lint.rs:410:17
    |
 LL |         let x = Deprecated2(1, 2, 3);
    |                 ^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2': text
-  --> $DIR/deprecation-lint.rs:419:13
+  --> $DIR/deprecation-lint.rs:420:13
    |
 LL |         let Deprecated2
    |             ^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2': text
-  --> $DIR/deprecation-lint.rs:428:13
+  --> $DIR/deprecation-lint.rs:429:13
    |
 LL |         let Deprecated2
    |             ^^^^^^^^^^^
@@ -593,136 +605,136 @@ LL |         <Foo>::trait_deprecated_text(&foo); //~ ERROR use of deprecated ite
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::DeprecatedStruct::i': text
-  --> $DIR/deprecation-lint.rs:269:13
+  --> $DIR/deprecation-lint.rs:270:13
    |
 LL |             i: 0 //~ ERROR use of deprecated item 'this_crate::DeprecatedStruct::i': text
    |             ^^^^
 
 error: use of deprecated item 'this_crate::nested::DeprecatedStruct::i': text
-  --> $DIR/deprecation-lint.rs:280:13
+  --> $DIR/deprecation-lint.rs:281:13
    |
 LL |             i: 0 //~ ERROR use of deprecated item 'this_crate::nested::DeprecatedStruct::i': text
    |             ^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated': text
-  --> $DIR/deprecation-lint.rs:291:13
+  --> $DIR/deprecation-lint.rs:292:13
    |
 LL |         foo.trait_deprecated(); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated'
    |             ^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated': text
-  --> $DIR/deprecation-lint.rs:293:9
+  --> $DIR/deprecation-lint.rs:294:9
    |
 LL |         <Foo>::trait_deprecated(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated'
    |         ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
-  --> $DIR/deprecation-lint.rs:295:13
+  --> $DIR/deprecation-lint.rs:296:13
    |
 LL |         foo.trait_deprecated_text(); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |             ^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
-  --> $DIR/deprecation-lint.rs:297:9
+  --> $DIR/deprecation-lint.rs:298:9
    |
 LL |         <Foo>::trait_deprecated_text(&foo); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated': text
-  --> $DIR/deprecation-lint.rs:302:13
+  --> $DIR/deprecation-lint.rs:303:13
    |
 LL |         foo.trait_deprecated(); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated'
    |             ^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
-  --> $DIR/deprecation-lint.rs:303:13
+  --> $DIR/deprecation-lint.rs:304:13
    |
 LL |         foo.trait_deprecated_text(); //~ ERROR use of deprecated item 'this_crate::Trait::trait_deprecated_text': text
    |             ^^^^^^^^^^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Stable::override2': text
-  --> $DIR/deprecation-lint.rs:362:13
+  --> $DIR/deprecation-lint.rs:363:13
    |
 LL |             override2: 3,
    |             ^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Stable::override2': text
-  --> $DIR/deprecation-lint.rs:366:17
+  --> $DIR/deprecation-lint.rs:367:17
    |
 LL |         let _ = x.override2;
    |                 ^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Stable::override2': text
-  --> $DIR/deprecation-lint.rs:370:13
+  --> $DIR/deprecation-lint.rs:371:13
    |
 LL |             override2: _
    |             ^^^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Stable2::2': text
-  --> $DIR/deprecation-lint.rs:378:17
+  --> $DIR/deprecation-lint.rs:379:17
    |
 LL |         let _ = x.2;
    |                 ^^^
 
 error: use of deprecated item 'this_crate2::Stable2::2': text
-  --> $DIR/deprecation-lint.rs:383:20
+  --> $DIR/deprecation-lint.rs:384:20
    |
 LL |                    _)
    |                    ^
 
 error: use of deprecated item 'this_crate2::Deprecated::inherit': text
-  --> $DIR/deprecation-lint.rs:391:13
+  --> $DIR/deprecation-lint.rs:392:13
    |
 LL |             inherit: 1,
    |             ^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated::inherit': text
-  --> $DIR/deprecation-lint.rs:395:17
+  --> $DIR/deprecation-lint.rs:396:17
    |
 LL |         let _ = x.inherit;
    |                 ^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated::inherit': text
-  --> $DIR/deprecation-lint.rs:400:13
+  --> $DIR/deprecation-lint.rs:401:13
    |
 LL |             inherit: _,
    |             ^^^^^^^^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2::0': text
-  --> $DIR/deprecation-lint.rs:412:17
+  --> $DIR/deprecation-lint.rs:413:17
    |
 LL |         let _ = x.0;
    |                 ^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2::1': text
-  --> $DIR/deprecation-lint.rs:414:17
+  --> $DIR/deprecation-lint.rs:415:17
    |
 LL |         let _ = x.1;
    |                 ^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2::2': text
-  --> $DIR/deprecation-lint.rs:416:17
+  --> $DIR/deprecation-lint.rs:417:17
    |
 LL |         let _ = x.2;
    |                 ^^^
 
 error: use of deprecated item 'this_crate2::Deprecated2::0': text
-  --> $DIR/deprecation-lint.rs:421:14
+  --> $DIR/deprecation-lint.rs:422:14
    |
 LL |             (_,
    |              ^
 
 error: use of deprecated item 'this_crate2::Deprecated2::1': text
-  --> $DIR/deprecation-lint.rs:423:14
+  --> $DIR/deprecation-lint.rs:424:14
    |
 LL |              _,
    |              ^
 
 error: use of deprecated item 'this_crate2::Deprecated2::2': text
-  --> $DIR/deprecation-lint.rs:425:14
+  --> $DIR/deprecation-lint.rs:426:14
    |
 LL |              _)
    |              ^
 
-error: aborting due to 120 previous errors
+error: aborting due to 122 previous errors
 
diff --git a/src/test/ui/deprecation/deprecation-sanity.rs b/src/test/ui/deprecation/deprecation-sanity.rs
index 09bae0bdfb13e..a559908b792bb 100644
--- a/src/test/ui/deprecation/deprecation-sanity.rs
+++ b/src/test/ui/deprecation/deprecation-sanity.rs
@@ -15,6 +15,12 @@ mod bogus_attribute_types_1 {
 
     #[deprecated(since(b), note = "a")] //~ ERROR incorrect meta item
     fn f6() { }
+
+    #[deprecated(note = b"test")] //~ ERROR literal in `deprecated` value must be a string
+    fn f7() { }
+
+    #[deprecated("test")] //~ ERROR item in `deprecated` must be a key/value pair
+    fn f8() { }
 }
 
 #[deprecated(since = "a", note = "b")]
diff --git a/src/test/ui/deprecation/deprecation-sanity.stderr b/src/test/ui/deprecation/deprecation-sanity.stderr
index a8bfcc23cc8cc..a071a4fc10d51 100644
--- a/src/test/ui/deprecation/deprecation-sanity.stderr
+++ b/src/test/ui/deprecation/deprecation-sanity.stderr
@@ -28,19 +28,31 @@ error[E0551]: incorrect meta item
 LL |     #[deprecated(since(b), note = "a")] //~ ERROR incorrect meta item
    |                  ^^^^^^^^
 
+error[E0565]: literal in `deprecated` value must be a string
+  --> $DIR/deprecation-sanity.rs:19:25
+   |
+LL |     #[deprecated(note = b"test")] //~ ERROR literal in `deprecated` value must be a string
+   |                         ^^^^^^^ help: consider removing the prefix: `"test"`
+
+error[E0565]: item in `deprecated` must be a key/value pair
+  --> $DIR/deprecation-sanity.rs:22:18
+   |
+LL |     #[deprecated("test")] //~ ERROR item in `deprecated` must be a key/value pair
+   |                  ^^^^^^
+
 error[E0550]: multiple deprecated attributes
-  --> $DIR/deprecation-sanity.rs:22:1
+  --> $DIR/deprecation-sanity.rs:28:1
    |
 LL | fn multiple1() { } //~ ERROR multiple deprecated attributes
    | ^^^^^^^^^^^^^^^^^^
 
 error[E0538]: multiple 'since' items
-  --> $DIR/deprecation-sanity.rs:24:27
+  --> $DIR/deprecation-sanity.rs:30:27
    |
 LL | #[deprecated(since = "a", since = "b", note = "c")] //~ ERROR multiple 'since' items
    |                           ^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: aborting due to 9 previous errors
 
-Some errors occurred: E0538, E0541, E0550, E0551.
+Some errors occurred: E0538, E0541, E0550, E0551, E0565.
 For more information about an error, try `rustc --explain E0538`.
diff --git a/src/test/ui/deprecation/invalid-literal.rs b/src/test/ui/deprecation/invalid-literal.rs
new file mode 100644
index 0000000000000..7e0d8cdfc2f72
--- /dev/null
+++ b/src/test/ui/deprecation/invalid-literal.rs
@@ -0,0 +1,4 @@
+#[deprecated = b"test"] //~ ERROR attribute must be of the form
+fn foo() {}
+
+fn main() {}
diff --git a/src/test/ui/deprecation/invalid-literal.stderr b/src/test/ui/deprecation/invalid-literal.stderr
new file mode 100644
index 0000000000000..f13d599c0b137
--- /dev/null
+++ b/src/test/ui/deprecation/invalid-literal.stderr
@@ -0,0 +1,8 @@
+error: attribute must be of the form `#[deprecated]` or `#[deprecated(/*opt*/ since = "version", /*opt*/ note = "reason)]` or `#[deprecated = "reason"]`
+  --> $DIR/invalid-literal.rs:1:1
+   |
+LL | #[deprecated = b"test"] //~ ERROR attribute must be of the form
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/deprecation/rustc_deprecation-in-future.rs b/src/test/ui/deprecation/rustc_deprecation-in-future.rs
new file mode 100644
index 0000000000000..a19363c512950
--- /dev/null
+++ b/src/test/ui/deprecation/rustc_deprecation-in-future.rs
@@ -0,0 +1,15 @@
+// ignore-tidy-linelength
+
+#![deny(deprecated_in_future)]
+
+#![feature(staged_api)]
+
+#![stable(feature = "rustc_deprecation-in-future-test", since = "1.0.0")]
+
+#[rustc_deprecated(since = "99.99.99", reason = "effectively never")]
+#[stable(feature = "rustc_deprecation-in-future-test", since = "1.0.0")]
+pub struct S;
+
+fn main() {
+    let _ = S; //~ ERROR use of item 'S' that will be deprecated in future version 99.99.99: effectively never
+}
diff --git a/src/test/ui/deprecation/rustc_deprecation-in-future.stderr b/src/test/ui/deprecation/rustc_deprecation-in-future.stderr
new file mode 100644
index 0000000000000..bd8ade16ec0e8
--- /dev/null
+++ b/src/test/ui/deprecation/rustc_deprecation-in-future.stderr
@@ -0,0 +1,14 @@
+error: use of item 'S' that will be deprecated in future version 99.99.99: effectively never
+  --> $DIR/rustc_deprecation-in-future.rs:14:13
+   |
+LL |     let _ = S; //~ ERROR use of item 'S' that will be deprecated in future version 99.99.99: effectively never
+   |             ^
+   |
+note: lint level defined here
+  --> $DIR/rustc_deprecation-in-future.rs:3:9
+   |
+LL | #![deny(deprecated_in_future)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/did_you_mean/issue-21659-show-relevant-trait-impls-2.stderr b/src/test/ui/did_you_mean/issue-21659-show-relevant-trait-impls-2.stderr
index 140f98b40382a..d6d5ce4d1a7d2 100644
--- a/src/test/ui/did_you_mean/issue-21659-show-relevant-trait-impls-2.stderr
+++ b/src/test/ui/did_you_mean/issue-21659-show-relevant-trait-impls-2.stderr
@@ -8,7 +8,7 @@ LL |     f1.foo(1usize);
              <Bar as Foo<i16>>
              <Bar as Foo<i32>>
              <Bar as Foo<i8>>
-             <Bar as Foo<u8>>
+             <Bar as Foo<u16>>
            and 2 others
 
 error: aborting due to previous error
diff --git a/src/test/ui/did_you_mean/issue-39802-show-5-trait-impls.stderr b/src/test/ui/did_you_mean/issue-39802-show-5-trait-impls.stderr
index 23466980f9252..3411958be62a9 100644
--- a/src/test/ui/did_you_mean/issue-39802-show-5-trait-impls.stderr
+++ b/src/test/ui/did_you_mean/issue-39802-show-5-trait-impls.stderr
@@ -40,10 +40,10 @@ LL |     Foo::<i32>::bar(&true); //~ ERROR is not satisfied
    |     ^^^^^^^^^^^^^^^ the trait `Foo<i32>` is not implemented for `bool`
    |
    = help: the following implementations were found:
+             <bool as Foo<bool>>
+             <bool as Foo<i8>>
              <bool as Foo<u16>>
              <bool as Foo<u32>>
-             <bool as Foo<u64>>
-             <bool as Foo<u8>>
            and 2 others
 note: required by `Foo::bar`
   --> $DIR/issue-39802-show-5-trait-impls.rs:2:5
diff --git a/src/test/ui/did_you_mean/issue-48492-tuple-destructure-missing-parens.stderr b/src/test/ui/did_you_mean/issue-48492-tuple-destructure-missing-parens.stderr
index 9df881e8e26d9..8099c3c0584fc 100644
--- a/src/test/ui/did_you_mean/issue-48492-tuple-destructure-missing-parens.stderr
+++ b/src/test/ui/did_you_mean/issue-48492-tuple-destructure-missing-parens.stderr
@@ -2,37 +2,85 @@ error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:38:17
    |
 LL |     while let b1, b2, b3 = reading_frame.next().expect("there should be a start codon") {
-   |               --^------- help: try adding parentheses: `(b1, b2, b3)`
+   |                 ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |     while let (b1, b2, b3) = reading_frame.next().expect("there should be a start codon") {
+   |               ^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |     while let b1 | b2 | b3 = reading_frame.next().expect("there should be a start codon") {
+   |               ^^^^^^^^^^^^
 
 error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:49:14
    |
 LL |     if let b1, b2, b3 = reading_frame.next().unwrap() {
-   |            --^------- help: try adding parentheses: `(b1, b2, b3)`
+   |              ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |     if let (b1, b2, b3) = reading_frame.next().unwrap() {
+   |            ^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |     if let b1 | b2 | b3 = reading_frame.next().unwrap() {
+   |            ^^^^^^^^^^^^
 
 error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:59:28
    |
 LL |         Nucleotide::Adenine, Nucleotide::Cytosine, _ => true
-   |         -------------------^------------------------ help: try adding parentheses: `(Nucleotide::Adenine, Nucleotide::Cytosine, _)`
+   |                            ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |         (Nucleotide::Adenine, Nucleotide::Cytosine, _) => true
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |         Nucleotide::Adenine | Nucleotide::Cytosine | _ => true
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:67:10
    |
 LL |     for x, _barr_body in women.iter().map(|woman| woman.allosomes.clone()) {
-   |         -^----------- help: try adding parentheses: `(x, _barr_body)`
+   |          ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |     for (x, _barr_body) in women.iter().map(|woman| woman.allosomes.clone()) {
+   |         ^^^^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |     for x | _barr_body in women.iter().map(|woman| woman.allosomes.clone()) {
+   |         ^^^^^^^^^^^^^^
 
 error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:75:10
    |
 LL |     for x, y @ Allosome::Y(_) in men.iter().map(|man| man.allosomes.clone()) {
-   |         -^------------------- help: try adding parentheses: `(x, y @ Allosome::Y(_))`
+   |          ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |     for (x, y @ Allosome::Y(_)) in men.iter().map(|man| man.allosomes.clone()) {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |     for x | y @ Allosome::Y(_) in men.iter().map(|man| man.allosomes.clone()) {
+   |         ^^^^^^^^^^^^^^^^^^^^^^
 
 error: unexpected `,` in pattern
   --> $DIR/issue-48492-tuple-destructure-missing-parens.rs:84:14
    |
 LL |     let women, men: (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
-   |         -----^---- help: try adding parentheses: `(women, men)`
+   |              ^
+help: try adding parentheses to match on a tuple..
+   |
+LL |     let (women, men): (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
+   |         ^^^^^^^^^^^^
+help: ..or a vertical bar to match on multiple alternatives
+   |
+LL |     let women | men: (Vec<Genome>, Vec<Genome>) = genomes.iter().cloned()
+   |         ^^^^^^^^^^^
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/did_you_mean/recursion_limit.stderr b/src/test/ui/did_you_mean/recursion_limit.stderr
index 08947fd7fdcba..0738c3f65b95f 100644
--- a/src/test/ui/did_you_mean/recursion_limit.stderr
+++ b/src/test/ui/did_you_mean/recursion_limit.stderr
@@ -1,11 +1,10 @@
-error[E0275]: overflow evaluating the requirement `K: std::marker::Send`
+error[E0275]: overflow evaluating the requirement `J: std::marker::Send`
   --> $DIR/recursion_limit.rs:34:5
    |
 LL |     is_send::<A>(); //~ ERROR overflow evaluating the requirement
    |     ^^^^^^^^^^^^
    |
    = help: consider adding a `#![recursion_limit="20"]` attribute to your crate
-   = note: required because it appears within the type `J`
    = note: required because it appears within the type `I`
    = note: required because it appears within the type `H`
    = note: required because it appears within the type `G`
diff --git a/src/test/ui/double-type-import.stderr b/src/test/ui/double-type-import.stderr
index 4bdee0c4c9f6c..c7288af13c278 100644
--- a/src/test/ui/double-type-import.stderr
+++ b/src/test/ui/double-type-import.stderr
@@ -4,13 +4,12 @@ error[E0252]: the name `X` is defined multiple times
 LL |     pub use self::bar::X;
    |             ------------ previous import of the type `X` here
 LL |     use self::bar::X;
-   |         ^^^^^^^^^^^^ `X` reimported here
+   |     ----^^^^^^^^^^^^-
+   |     |   |
+   |     |   `X` reimported here
+   |     help: remove unnecessary import
    |
    = note: `X` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL |     use self::bar::X as OtherX;
-   |         ^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/duplicate/duplicate-type-parameter.stderr b/src/test/ui/duplicate/duplicate-type-parameter.stderr
index 41750d4bb3625..17d48edc35c91 100644
--- a/src/test/ui/duplicate/duplicate-type-parameter.stderr
+++ b/src/test/ui/duplicate/duplicate-type-parameter.stderr
@@ -1,4 +1,4 @@
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:1:12
    |
 LL | type Foo<T,T> = Option<T>;
@@ -6,7 +6,7 @@ LL | type Foo<T,T> = Option<T>;
    |          |
    |          first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:4:14
    |
 LL | struct Bar<T,T>(T);
@@ -14,7 +14,7 @@ LL | struct Bar<T,T>(T);
    |            |
    |            first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:7:14
    |
 LL | struct Baz<T,T> {
@@ -22,7 +22,7 @@ LL | struct Baz<T,T> {
    |            |
    |            first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:12:12
    |
 LL | enum Boo<T,T> {
@@ -30,7 +30,7 @@ LL | enum Boo<T,T> {
    |          |
    |          first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:18:11
    |
 LL | fn quux<T,T>(x: T) {}
@@ -38,7 +38,7 @@ LL | fn quux<T,T>(x: T) {}
    |         |
    |         first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:21:13
    |
 LL | trait Qux<T,T> {}
@@ -46,7 +46,7 @@ LL | trait Qux<T,T> {}
    |           |
    |           first use of `T`
 
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/duplicate-type-parameter.rs:24:8
    |
 LL | impl<T,T> Qux<T,T> for Option<T> {}
diff --git a/src/test/ui/e0119/conflict-with-std.stderr b/src/test/ui/e0119/conflict-with-std.stderr
index d94e4dc5b6e79..c2ae321aa5e50 100644
--- a/src/test/ui/e0119/conflict-with-std.stderr
+++ b/src/test/ui/e0119/conflict-with-std.stderr
@@ -25,7 +25,7 @@ LL | impl TryFrom<X> for X { //~ ERROR conflicting implementations
    |
    = note: conflicting implementation in crate `core`:
            - impl<T, U> std::convert::TryFrom<U> for T
-             where T: std::convert::From<U>;
+             where U: std::convert::Into<T>;
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/empty/empty-struct-braces-expr.stderr b/src/test/ui/empty/empty-struct-braces-expr.stderr
index e595e0ccb9293..19844503a4804 100644
--- a/src/test/ui/empty/empty-struct-braces-expr.stderr
+++ b/src/test/ui/empty/empty-struct-braces-expr.stderr
@@ -51,20 +51,18 @@ error[E0599]: no variant named `Empty3` found for type `empty_struct::XE` in the
    |
 LL |     let xe3 = XE::Empty3; //~ ERROR no variant named `Empty3` found for type
    |               ----^^^^^^
-   |               |
+   |               |   |
+   |               |   help: did you mean: `XEmpty3`
    |               variant not found in `empty_struct::XE`
-   |
-   = help: did you mean `XEmpty3`?
 
 error[E0599]: no variant named `Empty3` found for type `empty_struct::XE` in the current scope
   --> $DIR/empty-struct-braces-expr.rs:23:19
    |
 LL |     let xe3 = XE::Empty3(); //~ ERROR no variant named `Empty3` found for type
    |               ----^^^^^^
-   |               |
+   |               |   |
+   |               |   help: did you mean: `XEmpty3`
    |               variant not found in `empty_struct::XE`
-   |
-   = help: did you mean `XEmpty3`?
 
 error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/error-codes/E0017.nll.stderr b/src/test/ui/error-codes/E0017.nll.stderr
index 305e85563ebc5..0477f06010b02 100644
--- a/src/test/ui/error-codes/E0017.nll.stderr
+++ b/src/test/ui/error-codes/E0017.nll.stderr
@@ -4,17 +4,17 @@ error[E0017]: references in constants may only refer to immutable values
 LL | const CR: &'static mut i32 = &mut C; //~ ERROR E0017
    |                              ^^^^^^ constants require immutable values
 
-error: cannot mutate statics in the initializer of another static
+error[E0017]: references in statics may only refer to immutable values
   --> $DIR/E0017.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^
+   |                                       ^^^^^^ statics require immutable values
 
-error[E0017]: references in statics may only refer to immutable values
+error: cannot mutate statics in the initializer of another static
   --> $DIR/E0017.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^ statics require immutable values
+   |                                       ^^^^^^
 
 error[E0596]: cannot borrow immutable static item `X` as mutable
   --> $DIR/E0017.rs:5:39
diff --git a/src/test/ui/error-codes/E0017.stderr b/src/test/ui/error-codes/E0017.stderr
index 93f5ca5545544..cc202ec912e96 100644
--- a/src/test/ui/error-codes/E0017.stderr
+++ b/src/test/ui/error-codes/E0017.stderr
@@ -4,17 +4,17 @@ error[E0017]: references in constants may only refer to immutable values
 LL | const CR: &'static mut i32 = &mut C; //~ ERROR E0017
    |                              ^^^^^^ constants require immutable values
 
-error: cannot mutate statics in the initializer of another static
+error[E0017]: references in statics may only refer to immutable values
   --> $DIR/E0017.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^
+   |                                       ^^^^^^ statics require immutable values
 
-error[E0017]: references in statics may only refer to immutable values
+error: cannot mutate statics in the initializer of another static
   --> $DIR/E0017.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^ statics require immutable values
+   |                                       ^^^^^^
 
 error[E0596]: cannot borrow immutable static item as mutable
   --> $DIR/E0017.rs:5:44
diff --git a/src/test/ui/error-codes/E0055.rs b/src/test/ui/error-codes/E0055.rs
index a3ade92d24f4c..b525575d98d46 100644
--- a/src/test/ui/error-codes/E0055.rs
+++ b/src/test/ui/error-codes/E0055.rs
@@ -1,4 +1,4 @@
-#![recursion_limit="2"]
+#![recursion_limit="5"]
 struct Foo;
 
 impl Foo {
@@ -7,7 +7,7 @@ impl Foo {
 
 fn main() {
     let foo = Foo;
-    let ref_foo = &&Foo;
+    let ref_foo = &&&&&Foo;
     ref_foo.foo();
     //~^ ERROR E0055
 }
diff --git a/src/test/ui/error-codes/E0055.stderr b/src/test/ui/error-codes/E0055.stderr
index cd2bd923d5a0f..d06566ffbe9a9 100644
--- a/src/test/ui/error-codes/E0055.stderr
+++ b/src/test/ui/error-codes/E0055.stderr
@@ -4,7 +4,7 @@ error[E0055]: reached the recursion limit while auto-dereferencing `Foo`
 LL |     ref_foo.foo();
    |             ^^^ deref recursion limit reached
    |
-   = help: consider adding a `#![recursion_limit="4"]` attribute to your crate
+   = help: consider adding a `#![recursion_limit="10"]` attribute to your crate
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0214.stderr b/src/test/ui/error-codes/E0214.stderr
index 08a98b1c3bf3d..a10f2c00578c6 100644
--- a/src/test/ui/error-codes/E0214.stderr
+++ b/src/test/ui/error-codes/E0214.stderr
@@ -1,8 +1,11 @@
-error[E0214]: parenthesized parameters may only be used with a trait
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/E0214.rs:2:15
    |
 LL |     let v: Vec(&str) = vec!["foo"];
-   |               ^^^^^^ only traits may use parentheses
+   |               ^^^^^^
+   |               |
+   |               only `Fn` traits may use parentheses
+   |               help: use angle brackets instead: `<&str>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/error-codes/E0275.stderr b/src/test/ui/error-codes/E0275.stderr
index 817b4828cc4ab..f2b0f392bc8bc 100644
--- a/src/test/ui/error-codes/E0275.stderr
+++ b/src/test/ui/error-codes/E0275.stderr
@@ -1,11 +1,10 @@
-error[E0275]: overflow evaluating the requirement `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: std::marker::Sized`
+error[E0275]: overflow evaluating the requirement `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Foo`
   --> $DIR/E0275.rs:5:1
    |
 LL | impl<T> Foo for T where Bar<T>: Foo {} //~ ERROR E0275
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider adding a `#![recursion_limit="128"]` attribute to your crate
-   = note: required because of the requirements on the impl of `Foo` for `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
diff --git a/src/test/ui/error-codes/E0388.nll.stderr b/src/test/ui/error-codes/E0388.nll.stderr
index 2bcda2ba8fb17..a898d60a98595 100644
--- a/src/test/ui/error-codes/E0388.nll.stderr
+++ b/src/test/ui/error-codes/E0388.nll.stderr
@@ -4,17 +4,17 @@ error[E0017]: references in constants may only refer to immutable values
 LL | const CR: &'static mut i32 = &mut C; //~ ERROR E0017
    |                              ^^^^^^ constants require immutable values
 
-error: cannot mutate statics in the initializer of another static
+error[E0017]: references in statics may only refer to immutable values
   --> $DIR/E0388.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^
+   |                                       ^^^^^^ statics require immutable values
 
-error[E0017]: references in statics may only refer to immutable values
+error: cannot mutate statics in the initializer of another static
   --> $DIR/E0388.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^ statics require immutable values
+   |                                       ^^^^^^
 
 error[E0596]: cannot borrow immutable static item `X` as mutable
   --> $DIR/E0388.rs:5:39
diff --git a/src/test/ui/error-codes/E0388.stderr b/src/test/ui/error-codes/E0388.stderr
index f35d39c7bb246..f641830ae9ff2 100644
--- a/src/test/ui/error-codes/E0388.stderr
+++ b/src/test/ui/error-codes/E0388.stderr
@@ -4,17 +4,17 @@ error[E0017]: references in constants may only refer to immutable values
 LL | const CR: &'static mut i32 = &mut C; //~ ERROR E0017
    |                              ^^^^^^ constants require immutable values
 
-error: cannot mutate statics in the initializer of another static
+error[E0017]: references in statics may only refer to immutable values
   --> $DIR/E0388.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^
+   |                                       ^^^^^^ statics require immutable values
 
-error[E0017]: references in statics may only refer to immutable values
+error: cannot mutate statics in the initializer of another static
   --> $DIR/E0388.rs:5:39
    |
 LL | static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
-   |                                       ^^^^^^ statics require immutable values
+   |                                       ^^^^^^
 
 error[E0596]: cannot borrow immutable static item as mutable
   --> $DIR/E0388.rs:5:44
diff --git a/src/test/ui/error-codes/E0395.rs b/src/test/ui/error-codes/E0395.rs
index c2de56c413f05..9657bbdeadc17 100644
--- a/src/test/ui/error-codes/E0395.rs
+++ b/src/test/ui/error-codes/E0395.rs
@@ -3,6 +3,6 @@
 static FOO: i32 = 42;
 static BAR: i32 = 42;
 
-static BAZ: bool = { (&FOO as *const i32) == (&BAR as *const i32) }; //~ ERROR issue #53020
+static BAZ: bool = unsafe { (&FOO as *const i32) == (&BAR as *const i32) }; //~ ERROR issue #53020
 fn main() {
 }
diff --git a/src/test/ui/error-codes/E0395.stderr b/src/test/ui/error-codes/E0395.stderr
index 45e1ba05ff996..cc7d94e22eb6b 100644
--- a/src/test/ui/error-codes/E0395.stderr
+++ b/src/test/ui/error-codes/E0395.stderr
@@ -1,8 +1,8 @@
 error[E0658]: comparing raw pointers inside static (see issue #53020)
-  --> $DIR/E0395.rs:6:22
+  --> $DIR/E0395.rs:6:29
    |
-LL | static BAZ: bool = { (&FOO as *const i32) == (&BAR as *const i32) }; //~ ERROR issue #53020
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | static BAZ: bool = unsafe { (&FOO as *const i32) == (&BAR as *const i32) }; //~ ERROR issue #53020
+   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(const_compare_raw_pointers)] to the crate attributes to enable
 
diff --git a/src/test/ui/error-codes/E0401.stderr b/src/test/ui/error-codes/E0401.stderr
index c94fa497678e0..27f281ee43786 100644
--- a/src/test/ui/error-codes/E0401.stderr
+++ b/src/test/ui/error-codes/E0401.stderr
@@ -1,26 +1,26 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/E0401.rs:4:39
    |
 LL | fn foo<T>(x: T) {
    |        - type variable from outer function
 LL |     fn bfnr<U, V: Baz<U>, W: Fn()>(y: T) { //~ ERROR E0401
-   |        ---------------------------    ^ use of type variable from outer function
+   |        ---------------------------    ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `bfnr<U, V: Baz<U>, W: Fn(), T>`
+   |        help: try using a local generic parameter instead: `bfnr<U, V: Baz<U>, W: Fn(), T>`
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/E0401.rs:9:16
    |
 LL | fn foo<T>(x: T) {
    |        - type variable from outer function
 ...
 LL |     fn baz<U,
-   |        --- try adding a local type parameter in this method instead
+   |        --- try adding a local generic parameter in this method instead
 ...
 LL |            (y: T) { //~ ERROR E0401
-   |                ^ use of type variable from outer function
+   |                ^ use of generic parameter from outer function
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/E0401.rs:22:25
    |
 LL | impl<T> Iterator for A<T> {
@@ -29,7 +29,7 @@ LL | impl<T> Iterator for A<T> {
 LL |         fn helper(sel: &Self) -> u8 { //~ ERROR E0401
    |                         ^^^^
    |                         |
-   |                         use of type variable from outer function
+   |                         use of generic parameter from outer function
    |                         use a type here instead
 
 error: aborting due to 3 previous errors
diff --git a/src/test/ui/error-codes/E0403.stderr b/src/test/ui/error-codes/E0403.stderr
index 919a82dbe1a72..b924647502965 100644
--- a/src/test/ui/error-codes/E0403.stderr
+++ b/src/test/ui/error-codes/E0403.stderr
@@ -1,4 +1,4 @@
-error[E0403]: the name `T` is already used for a type parameter in this type parameter list
+error[E0403]: the name `T` is already used for a generic parameter in this list of generic parameters
   --> $DIR/E0403.rs:1:11
    |
 LL | fn foo<T, T>(s: T, u: T) {} //~ ERROR E0403
diff --git a/src/test/ui/error-codes/E0423.stderr b/src/test/ui/error-codes/E0423.stderr
index c422a1e79574b..d0deb8ce7ea26 100644
--- a/src/test/ui/error-codes/E0423.stderr
+++ b/src/test/ui/error-codes/E0423.stderr
@@ -29,19 +29,25 @@ error[E0423]: expected value, found struct `S`
   --> $DIR/E0423.rs:12:32
    |
 LL |     if let S { x: _x, y: 2 } = S { x: 1, y: 2 } { println!("Ok"); }
-   |                                ^ did you mean `(S { /* fields */ })`?
+   |                                ^---------------
+   |                                |
+   |                                help: surround the struct literal with parenthesis: `(S { x: 1, y: 2 })`
 
 error[E0423]: expected value, found struct `T`
   --> $DIR/E0423.rs:15:8
    |
 LL |     if T {} == T {} { println!("Ok"); }
-   |        ^ did you mean `(T { /* fields */ })`?
+   |        ^---
+   |        |
+   |        help: surround the struct literal with parenthesis: `(T {})`
 
 error[E0423]: expected value, found struct `std::ops::Range`
   --> $DIR/E0423.rs:21:14
    |
 LL |     for _ in std::ops::Range { start: 0, end: 10 } {}
-   |              ^^^^^^^^^^^^^^^ did you mean `(std::ops::Range { /* fields */ })`?
+   |              ^^^^^^^^^^^^^^^----------------------
+   |              |
+   |              help: surround the struct literal with parenthesis: `(std::ops::Range { start: 0, end: 10 })`
 
 error: aborting due to 7 previous errors
 
diff --git a/src/test/ui/error-codes/E0430.stderr b/src/test/ui/error-codes/E0430.stderr
index 0151cde887f1d..78e4e43ac2f3d 100644
--- a/src/test/ui/error-codes/E0430.stderr
+++ b/src/test/ui/error-codes/E0430.stderr
@@ -10,15 +10,13 @@ error[E0252]: the name `fmt` is defined multiple times
   --> $DIR/E0430.rs:1:22
    |
 LL | use std::fmt::{self, self}; //~ ERROR E0430
-   |                ----  ^^^^ `fmt` reimported here
-   |                |
+   |                ------^^^^
+   |                |   | |
+   |                |   | `fmt` reimported here
+   |                |   help: remove unnecessary import
    |                previous import of the module `fmt` here
    |
    = note: `fmt` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use std::fmt::{self, self as other_fmt}; //~ ERROR E0430
-   |                      ^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/error-codes/E0446.rs b/src/test/ui/error-codes/E0446.rs
index 33bd6144716c8..f61c7e5461662 100644
--- a/src/test/ui/error-codes/E0446.rs
+++ b/src/test/ui/error-codes/E0446.rs
@@ -1,4 +1,4 @@
-mod Foo {
+mod foo {
     struct Bar(u32);
 
     pub fn bar() -> Bar { //~ ERROR E0446
diff --git a/src/test/ui/error-codes/E0446.stderr b/src/test/ui/error-codes/E0446.stderr
index 8f381320cf99e..9c7399515f439 100644
--- a/src/test/ui/error-codes/E0446.stderr
+++ b/src/test/ui/error-codes/E0446.stderr
@@ -1,8 +1,8 @@
-error[E0446]: private type `Foo::Bar` in public interface
+error[E0446]: private type `foo::Bar` in public interface
   --> $DIR/E0446.rs:4:5
    |
 LL |       struct Bar(u32);
-   |       - `Foo::Bar` declared as private
+   |       - `foo::Bar` declared as private
 LL | 
 LL | /     pub fn bar() -> Bar { //~ ERROR E0446
 LL | |         Bar(0)
diff --git a/src/test/ui/error-codes/E0451.rs b/src/test/ui/error-codes/E0451.rs
index 7c1c326fb5bec..aa8f051afa777 100644
--- a/src/test/ui/error-codes/E0451.rs
+++ b/src/test/ui/error-codes/E0451.rs
@@ -1,4 +1,4 @@
-mod Bar {
+mod bar {
     pub struct Foo {
         pub a: isize,
         b: isize,
@@ -10,10 +10,10 @@ mod Bar {
     );
 }
 
-fn pat_match(foo: Bar::Foo) {
-    let Bar::Foo{a:a, b:b} = foo; //~ ERROR E0451
+fn pat_match(foo: bar::Foo) {
+    let bar::Foo{a, b} = foo; //~ ERROR E0451
 }
 
 fn main() {
-    let f = Bar::Foo{ a: 0, b: 0 }; //~ ERROR E0451
+    let f = bar::Foo{ a: 0, b: 0 }; //~ ERROR E0451
 }
diff --git a/src/test/ui/error-codes/E0451.stderr b/src/test/ui/error-codes/E0451.stderr
index 11bc7e31803a7..11f0867724627 100644
--- a/src/test/ui/error-codes/E0451.stderr
+++ b/src/test/ui/error-codes/E0451.stderr
@@ -1,13 +1,13 @@
-error[E0451]: field `b` of struct `Bar::Foo` is private
-  --> $DIR/E0451.rs:14:23
+error[E0451]: field `b` of struct `bar::Foo` is private
+  --> $DIR/E0451.rs:14:21
    |
-LL |     let Bar::Foo{a:a, b:b} = foo; //~ ERROR E0451
-   |                       ^^^ field `b` is private
+LL |     let bar::Foo{a, b} = foo; //~ ERROR E0451
+   |                     ^ field `b` is private
 
-error[E0451]: field `b` of struct `Bar::Foo` is private
+error[E0451]: field `b` of struct `bar::Foo` is private
   --> $DIR/E0451.rs:18:29
    |
-LL |     let f = Bar::Foo{ a: 0, b: 0 }; //~ ERROR E0451
+LL |     let f = bar::Foo{ a: 0, b: 0 }; //~ ERROR E0451
    |                             ^^^^ field `b` is private
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/error-codes/E0492.rs b/src/test/ui/error-codes/E0492.rs
index b1824941adf00..2de4c12eb64fb 100644
--- a/src/test/ui/error-codes/E0492.rs
+++ b/src/test/ui/error-codes/E0492.rs
@@ -1,6 +1,6 @@
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT};
+use std::sync::atomic::AtomicUsize;
 
-const A: AtomicUsize = ATOMIC_USIZE_INIT;
+const A: AtomicUsize = AtomicUsize::new(0);
 static B: &'static AtomicUsize = &A; //~ ERROR E0492
 
 fn main() {
diff --git a/src/test/ui/existential_types/auxiliary/cross_crate_ice.rs b/src/test/ui/existential_types/auxiliary/cross_crate_ice.rs
new file mode 100644
index 0000000000000..af2d209826e19
--- /dev/null
+++ b/src/test/ui/existential_types/auxiliary/cross_crate_ice.rs
@@ -0,0 +1,12 @@
+// Crate that exports an existential type. Used for testing cross-crate.
+
+#![crate_type="rlib"]
+
+#![feature(existential_type)]
+
+pub existential type Foo: std::fmt::Debug;
+
+pub fn foo() -> Foo {
+    5
+}
+
diff --git a/src/test/ui/existential_types/auxiliary/cross_crate_ice2.rs b/src/test/ui/existential_types/auxiliary/cross_crate_ice2.rs
new file mode 100644
index 0000000000000..39ec5394febe4
--- /dev/null
+++ b/src/test/ui/existential_types/auxiliary/cross_crate_ice2.rs
@@ -0,0 +1,21 @@
+// Crate that exports an existential type. Used for testing cross-crate.
+
+#![crate_type="rlib"]
+
+#![feature(existential_type)]
+
+pub trait View {
+    type Tmp: Iterator<Item = u32>;
+
+    fn test(&self) -> Self::Tmp;
+}
+
+pub struct X;
+
+impl View for X {
+    existential type Tmp: Iterator<Item = u32>;
+
+    fn test(&self) -> Self::Tmp {
+        vec![1,2,3].into_iter()
+    }
+}
diff --git a/src/test/ui/existential_types/bound_reduction2.rs b/src/test/ui/existential_types/bound_reduction2.rs
index d8ade50c79c82..542e076d88d64 100644
--- a/src/test/ui/existential_types/bound_reduction2.rs
+++ b/src/test/ui/existential_types/bound_reduction2.rs
@@ -8,11 +8,12 @@ trait TraitWithAssoc {
 }
 
 existential type Foo<V>: Trait<V>;
+//~^ ERROR could not find defining uses
 
 trait Trait<U> {}
 
 impl<W> Trait<W> for () {}
 
-fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T::Assoc> { //~ ERROR non-defining
+fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T::Assoc> { //~ ERROR does not fully define
     ()
 }
diff --git a/src/test/ui/existential_types/bound_reduction2.stderr b/src/test/ui/existential_types/bound_reduction2.stderr
index 8e822ca6d8bc7..f51f1c9a4e563 100644
--- a/src/test/ui/existential_types/bound_reduction2.stderr
+++ b/src/test/ui/existential_types/bound_reduction2.stderr
@@ -1,16 +1,16 @@
-error: non-defining existential type use in defining scope
-  --> $DIR/bound_reduction2.rs:16:1
+error: defining existential type use does not fully define existential type
+  --> $DIR/bound_reduction2.rs:17:1
    |
-LL | / fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T::Assoc> { //~ ERROR non-defining
+LL | / fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T::Assoc> { //~ ERROR does not fully define
 LL | |     ()
 LL | | }
    | |_^
-   |
-note: used non-generic type <T as TraitWithAssoc>::Assoc for generic parameter
-  --> $DIR/bound_reduction2.rs:10:22
+
+error: could not find defining uses
+  --> $DIR/bound_reduction2.rs:10:1
    |
 LL | existential type Foo<V>: Trait<V>;
-   |                      ^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/existential_types/cross_crate_ice.rs b/src/test/ui/existential_types/cross_crate_ice.rs
new file mode 100644
index 0000000000000..c5d5ca916a48a
--- /dev/null
+++ b/src/test/ui/existential_types/cross_crate_ice.rs
@@ -0,0 +1,16 @@
+// aux-build:cross_crate_ice.rs
+// compile-pass
+
+extern crate cross_crate_ice;
+
+struct Bar(cross_crate_ice::Foo);
+
+impl Bar {
+    fn zero(&self) -> &cross_crate_ice::Foo {
+        &self.0
+    }
+}
+
+fn main() {
+    let _ = cross_crate_ice::foo();
+}
diff --git a/src/test/ui/existential_types/cross_crate_ice2.rs b/src/test/ui/existential_types/cross_crate_ice2.rs
new file mode 100644
index 0000000000000..a0f3933ce33b2
--- /dev/null
+++ b/src/test/ui/existential_types/cross_crate_ice2.rs
@@ -0,0 +1,11 @@
+// aux-build:cross_crate_ice2.rs
+// compile-pass
+
+extern crate cross_crate_ice2;
+
+use cross_crate_ice2::View;
+
+fn main() {
+    let v = cross_crate_ice2::X;
+    v.test();
+}
diff --git a/src/test/ui/existential_types/different_defining_uses.rs b/src/test/ui/existential_types/different_defining_uses.rs
index c51fca75a24e9..a8670cc07f2e1 100644
--- a/src/test/ui/existential_types/different_defining_uses.rs
+++ b/src/test/ui/existential_types/different_defining_uses.rs
@@ -9,6 +9,6 @@ fn foo() -> Foo {
     ""
 }
 
-fn bar() -> Foo { //~ ERROR defining existential type use differs from previous
+fn bar() -> Foo { //~ ERROR concrete type differs from previous
     42i32
 }
diff --git a/src/test/ui/existential_types/different_defining_uses.stderr b/src/test/ui/existential_types/different_defining_uses.stderr
index f782a00229732..3f9ed96400b54 100644
--- a/src/test/ui/existential_types/different_defining_uses.stderr
+++ b/src/test/ui/existential_types/different_defining_uses.stderr
@@ -1,10 +1,10 @@
-error: defining existential type use differs from previous
+error: concrete type differs from previous defining existential type use
   --> $DIR/different_defining_uses.rs:12:1
    |
-LL | / fn bar() -> Foo { //~ ERROR defining existential type use differs from previous
+LL | / fn bar() -> Foo { //~ ERROR concrete type differs from previous
 LL | |     42i32
 LL | | }
-   | |_^
+   | |_^ expected `&'static str`, got `i32`
    |
 note: previous use here
   --> $DIR/different_defining_uses.rs:8:1
diff --git a/src/test/ui/existential_types/different_defining_uses_never_type.rs b/src/test/ui/existential_types/different_defining_uses_never_type.rs
index c6c6ae8d2dccf..13ada63e4bc45 100644
--- a/src/test/ui/existential_types/different_defining_uses_never_type.rs
+++ b/src/test/ui/existential_types/different_defining_uses_never_type.rs
@@ -9,10 +9,10 @@ fn foo() -> Foo {
     ""
 }
 
-fn bar() -> Foo { //~ ERROR defining existential type use differs from previous
+fn bar() -> Foo { //~ ERROR concrete type differs from previous
     panic!()
 }
 
-fn boo() -> Foo { //~ ERROR defining existential type use differs from previous
+fn boo() -> Foo { //~ ERROR concrete type differs from previous
     loop {}
 }
diff --git a/src/test/ui/existential_types/different_defining_uses_never_type.stderr b/src/test/ui/existential_types/different_defining_uses_never_type.stderr
index 04b0cf2778455..e29256a5014f9 100644
--- a/src/test/ui/existential_types/different_defining_uses_never_type.stderr
+++ b/src/test/ui/existential_types/different_defining_uses_never_type.stderr
@@ -1,10 +1,10 @@
-error: defining existential type use differs from previous
+error: concrete type differs from previous defining existential type use
   --> $DIR/different_defining_uses_never_type.rs:12:1
    |
-LL | / fn bar() -> Foo { //~ ERROR defining existential type use differs from previous
+LL | / fn bar() -> Foo { //~ ERROR concrete type differs from previous
 LL | |     panic!()
 LL | | }
-   | |_^
+   | |_^ expected `&'static str`, got `()`
    |
 note: previous use here
   --> $DIR/different_defining_uses_never_type.rs:8:1
@@ -14,13 +14,13 @@ LL | |     ""
 LL | | }
    | |_^
 
-error: defining existential type use differs from previous
+error: concrete type differs from previous defining existential type use
   --> $DIR/different_defining_uses_never_type.rs:16:1
    |
-LL | / fn boo() -> Foo { //~ ERROR defining existential type use differs from previous
+LL | / fn boo() -> Foo { //~ ERROR concrete type differs from previous
 LL | |     loop {}
 LL | | }
-   | |_^
+   | |_^ expected `&'static str`, got `()`
    |
 note: previous use here
   --> $DIR/different_defining_uses_never_type.rs:8:1
diff --git a/src/test/ui/existential_types/generic_different_defining_uses.rs b/src/test/ui/existential_types/generic_different_defining_uses.rs
index 3bd104251fb70..ce3ab88a1c0bb 100644
--- a/src/test/ui/existential_types/generic_different_defining_uses.rs
+++ b/src/test/ui/existential_types/generic_different_defining_uses.rs
@@ -8,6 +8,6 @@ fn my_iter<T>(t: T) -> MyIter<T> {
     std::iter::once(t)
 }
 
-fn my_iter2<T>(t: T) -> MyIter<T> { //~ ERROR defining existential type use differs from previous
+fn my_iter2<T>(t: T) -> MyIter<T> { //~ ERROR concrete type differs from previous
     Some(t).into_iter()
 }
diff --git a/src/test/ui/existential_types/generic_different_defining_uses.stderr b/src/test/ui/existential_types/generic_different_defining_uses.stderr
index 234bcf232ae79..3f129658b8fd0 100644
--- a/src/test/ui/existential_types/generic_different_defining_uses.stderr
+++ b/src/test/ui/existential_types/generic_different_defining_uses.stderr
@@ -1,10 +1,10 @@
-error: defining existential type use differs from previous
+error: concrete type differs from previous defining existential type use
   --> $DIR/generic_different_defining_uses.rs:11:1
    |
-LL | / fn my_iter2<T>(t: T) -> MyIter<T> { //~ ERROR defining existential type use differs from previous
+LL | / fn my_iter2<T>(t: T) -> MyIter<T> { //~ ERROR concrete type differs from previous
 LL | |     Some(t).into_iter()
 LL | | }
-   | |_^
+   | |_^ expected `std::iter::Once<T>`, got `std::option::IntoIter<T>`
    |
 note: previous use here
   --> $DIR/generic_different_defining_uses.rs:7:1
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use.rs b/src/test/ui/existential_types/generic_duplicate_param_use.rs
index 380fbdeb8c27c..3f8753333aa7a 100644
--- a/src/test/ui/existential_types/generic_duplicate_param_use.rs
+++ b/src/test/ui/existential_types/generic_duplicate_param_use.rs
@@ -1,9 +1,14 @@
 #![feature(existential_type)]
 
+use std::fmt::Debug;
+
 fn main() {}
 
-existential type Two<T, U>: 'static; //~ ERROR type parameter `U` is unused
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+//~^ could not find defining uses
 
-fn one<T: 'static>(t: T) -> Two<T, T> {
+fn one<T: Debug>(t: T) -> Two<T, T> {
+//~^ ERROR defining existential type use restricts existential type
     t
 }
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use.stderr b/src/test/ui/existential_types/generic_duplicate_param_use.stderr
index 66706c210541c..d4deda999da16 100644
--- a/src/test/ui/existential_types/generic_duplicate_param_use.stderr
+++ b/src/test/ui/existential_types/generic_duplicate_param_use.stderr
@@ -1,9 +1,17 @@
-error[E0091]: type parameter `U` is unused
-  --> $DIR/generic_duplicate_param_use.rs:5:25
+error: defining existential type use restricts existential type by using the generic parameter `T` twice
+  --> $DIR/generic_duplicate_param_use.rs:11:1
    |
-LL | existential type Two<T, U>: 'static; //~ ERROR type parameter `U` is unused
-   |                         ^ unused type parameter
+LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
+LL | | //~^ ERROR defining existential type use restricts existential type
+LL | |     t
+LL | | }
+   | |_^
 
-error: aborting due to previous error
+error: could not find defining uses
+  --> $DIR/generic_duplicate_param_use.rs:8:1
+   |
+LL | existential type Two<T, U>: Debug;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0091`.
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use10.rs b/src/test/ui/existential_types/generic_duplicate_param_use10.rs
new file mode 100644
index 0000000000000..10f2c630582fc
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use10.rs
@@ -0,0 +1,12 @@
+// compile-pass
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+existential type Two<T, U>: Debug;
+
+fn two<T: Debug, U: Debug>(t: T, _: U) -> Two<T, U> {
+    (t, 4u32)
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use2.rs b/src/test/ui/existential_types/generic_duplicate_param_use2.rs
new file mode 100644
index 0000000000000..3842292decd57
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use2.rs
@@ -0,0 +1,17 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+
+fn one<T: Debug>(t: T) -> Two<T, T> {
+//~^ defining existential type use restricts existential type
+    t
+}
+
+fn two<T: Debug, U>(t: T, _: U) -> Two<T, U> {
+    t
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use2.stderr b/src/test/ui/existential_types/generic_duplicate_param_use2.stderr
new file mode 100644
index 0000000000000..0a8be3218c759
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use2.stderr
@@ -0,0 +1,11 @@
+error: defining existential type use restricts existential type by using the generic parameter `T` twice
+  --> $DIR/generic_duplicate_param_use2.rs:10:1
+   |
+LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
+LL | | //~^ defining existential type use restricts existential type
+LL | |     t
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use3.rs b/src/test/ui/existential_types/generic_duplicate_param_use3.rs
new file mode 100644
index 0000000000000..05c77c8947333
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use3.rs
@@ -0,0 +1,22 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+
+fn one<T: Debug>(t: T) -> Two<T, T> {
+//~^ defining existential type use restricts existential type
+    t
+}
+
+fn two<T: Debug, U>(t: T, _: U) -> Two<T, U> {
+    t
+}
+
+fn three<T, U: Debug>(_: T, u: U) -> Two<T, U> {
+//~^ concrete type's generic parameters differ from previous defining use
+    u
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use3.stderr b/src/test/ui/existential_types/generic_duplicate_param_use3.stderr
new file mode 100644
index 0000000000000..1c96c15a76919
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use3.stderr
@@ -0,0 +1,28 @@
+error: defining existential type use restricts existential type by using the generic parameter `T` twice
+  --> $DIR/generic_duplicate_param_use3.rs:10:1
+   |
+LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
+LL | | //~^ defining existential type use restricts existential type
+LL | |     t
+LL | | }
+   | |_^
+
+error: concrete type's generic parameters differ from previous defining use
+  --> $DIR/generic_duplicate_param_use3.rs:19:1
+   |
+LL | / fn three<T, U: Debug>(_: T, u: U) -> Two<T, U> {
+LL | | //~^ concrete type's generic parameters differ from previous defining use
+LL | |     u
+LL | | }
+   | |_^ expected [`T`], got [`U`]
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use3.rs:15:1
+   |
+LL | / fn two<T: Debug, U>(t: T, _: U) -> Two<T, U> {
+LL | |     t
+LL | | }
+   | |_^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use4.rs b/src/test/ui/existential_types/generic_duplicate_param_use4.rs
new file mode 100644
index 0000000000000..609dbe06cd733
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use4.rs
@@ -0,0 +1,17 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+
+fn one<T: Debug>(t: T) -> Two<T, T> {
+//~^ ERROR defining existential type use restricts existential type
+    t
+}
+
+fn three<T, U: Debug>(_: T, u: U) -> Two<T, U> {
+    u
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use4.stderr b/src/test/ui/existential_types/generic_duplicate_param_use4.stderr
new file mode 100644
index 0000000000000..24b1caf7c1bfe
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use4.stderr
@@ -0,0 +1,11 @@
+error: defining existential type use restricts existential type by using the generic parameter `T` twice
+  --> $DIR/generic_duplicate_param_use4.rs:10:1
+   |
+LL | / fn one<T: Debug>(t: T) -> Two<T, T> {
+LL | | //~^ ERROR defining existential type use restricts existential type
+LL | |     t
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use5.rs b/src/test/ui/existential_types/generic_duplicate_param_use5.rs
new file mode 100644
index 0000000000000..3f4a23b8b41fa
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use5.rs
@@ -0,0 +1,17 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+
+fn two<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (t, u)
+}
+
+fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+//~^ concrete type differs from previous
+    (u, t)
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use5.stderr b/src/test/ui/existential_types/generic_duplicate_param_use5.stderr
new file mode 100644
index 0000000000000..166623801c246
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use5.stderr
@@ -0,0 +1,19 @@
+error: concrete type differs from previous defining existential type use
+  --> $DIR/generic_duplicate_param_use5.rs:14:1
+   |
+LL | / fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | | //~^ concrete type differs from previous
+LL | |     (u, t)
+LL | | }
+   | |_^ expected `(T, U)`, got `(U, T)`
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use5.rs:10:1
+   |
+LL | / fn two<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | |     (t, u)
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use6.rs b/src/test/ui/existential_types/generic_duplicate_param_use6.rs
new file mode 100644
index 0000000000000..3b8c56352bda4
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use6.rs
@@ -0,0 +1,17 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+// test that unused generic parameters are ok
+existential type Two<T, U>: Debug;
+
+fn two<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (t, t)
+}
+
+fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+//~^ concrete type differs from previous
+    (u, t)
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use6.stderr b/src/test/ui/existential_types/generic_duplicate_param_use6.stderr
new file mode 100644
index 0000000000000..da49a83be1f70
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use6.stderr
@@ -0,0 +1,19 @@
+error: concrete type differs from previous defining existential type use
+  --> $DIR/generic_duplicate_param_use6.rs:14:1
+   |
+LL | / fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | | //~^ concrete type differs from previous
+LL | |     (u, t)
+LL | | }
+   | |_^ expected `(T, T)`, got `(U, T)`
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use6.rs:10:1
+   |
+LL | / fn two<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | |     (t, t)
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use7.rs b/src/test/ui/existential_types/generic_duplicate_param_use7.rs
new file mode 100644
index 0000000000000..2bcac315f5a96
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use7.rs
@@ -0,0 +1,25 @@
+// compile-pass
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+existential type Two<A, B>: Debug;
+
+fn two<T: Debug + Copy, U>(t: T, u: U) -> Two<T, U> {
+    (t, t)
+}
+
+fn three<T: Debug, U>(t: T, t2: T, u: U) -> Two<T, U> {
+    (t, t2)
+}
+
+fn four<T: Debug, U, V>(t: T, t2: T, u: U, v: V) -> Two<T, U> {
+    (t, t2)
+}
+
+fn five<X, Y: Debug>(x: X, y: Y, y2: Y) -> Two<Y, X> {
+    (y, y2)
+}
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use8.rs b/src/test/ui/existential_types/generic_duplicate_param_use8.rs
new file mode 100644
index 0000000000000..83501ad8c41a7
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use8.rs
@@ -0,0 +1,16 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+existential type Two<T, U>: Debug;
+
+fn two<T: Debug, U: Debug>(t: T, _: U) -> Two<T, U> {
+    (t, 4u32)
+}
+
+fn three<T: Debug, U: Debug>(_: T, u: U) -> Two<T, U> {
+//~^ concrete type differs from previous
+    (u, 4u32)
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use8.stderr b/src/test/ui/existential_types/generic_duplicate_param_use8.stderr
new file mode 100644
index 0000000000000..80c7441c857d1
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use8.stderr
@@ -0,0 +1,19 @@
+error: concrete type differs from previous defining existential type use
+  --> $DIR/generic_duplicate_param_use8.rs:13:1
+   |
+LL | / fn three<T: Debug, U: Debug>(_: T, u: U) -> Two<T, U> {
+LL | | //~^ concrete type differs from previous
+LL | |     (u, 4u32)
+LL | | }
+   | |_^ expected `(T, u32)`, got `(U, u32)`
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use8.rs:9:1
+   |
+LL | / fn two<T: Debug, U: Debug>(t: T, _: U) -> Two<T, U> {
+LL | |     (t, 4u32)
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use9.rs b/src/test/ui/existential_types/generic_duplicate_param_use9.rs
new file mode 100644
index 0000000000000..4c6897298c44f
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use9.rs
@@ -0,0 +1,20 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+existential type Two<A, B>: Debug;
+
+trait Foo {
+    type Bar: Debug;
+    const BAR: Self::Bar;
+}
+
+fn two<T: Debug + Foo, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (t, u, T::BAR)
+}
+
+fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+    (t, u, 42) //~^ ERROR concrete type differs from previous
+}
diff --git a/src/test/ui/existential_types/generic_duplicate_param_use9.stderr b/src/test/ui/existential_types/generic_duplicate_param_use9.stderr
new file mode 100644
index 0000000000000..a3ce480d66dcd
--- /dev/null
+++ b/src/test/ui/existential_types/generic_duplicate_param_use9.stderr
@@ -0,0 +1,18 @@
+error: concrete type differs from previous defining existential type use
+  --> $DIR/generic_duplicate_param_use9.rs:18:1
+   |
+LL | / fn three<T: Debug, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | |     (t, u, 42) //~^ ERROR concrete type differs from previous
+LL | | }
+   | |_^ expected `(A, B, <A as Foo>::Bar)`, got `(A, B, i32)`
+   |
+note: previous use here
+  --> $DIR/generic_duplicate_param_use9.rs:14:1
+   |
+LL | / fn two<T: Debug + Foo, U: Debug>(t: T, u: U) -> Two<T, U> {
+LL | |     (t, u, T::BAR)
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/existential_types/generic_nondefining_use.rs b/src/test/ui/existential_types/generic_nondefining_use.rs
index caa8f0f2ee1bc..75af5d9570ff2 100644
--- a/src/test/ui/existential_types/generic_nondefining_use.rs
+++ b/src/test/ui/existential_types/generic_nondefining_use.rs
@@ -3,8 +3,9 @@
 fn main() {}
 
 existential type Cmp<T>: 'static;
+//~^ ERROR could not find defining uses
 
 // not a defining use, because it doesn't define *all* possible generics
-fn cmp() -> Cmp<u32> { //~ ERROR non-defining existential type use in defining scope
+fn cmp() -> Cmp<u32> { //~ ERROR defining existential type use does not fully define
     5u32
 }
diff --git a/src/test/ui/existential_types/generic_nondefining_use.stderr b/src/test/ui/existential_types/generic_nondefining_use.stderr
index 41877791e9ae9..8dd88006be9c6 100644
--- a/src/test/ui/existential_types/generic_nondefining_use.stderr
+++ b/src/test/ui/existential_types/generic_nondefining_use.stderr
@@ -1,16 +1,16 @@
-error: non-defining existential type use in defining scope
-  --> $DIR/generic_nondefining_use.rs:8:1
+error: defining existential type use does not fully define existential type
+  --> $DIR/generic_nondefining_use.rs:9:1
    |
-LL | / fn cmp() -> Cmp<u32> { //~ ERROR non-defining existential type use in defining scope
+LL | / fn cmp() -> Cmp<u32> { //~ ERROR defining existential type use does not fully define
 LL | |     5u32
 LL | | }
    | |_^
-   |
-note: used non-generic type u32 for generic parameter
-  --> $DIR/generic_nondefining_use.rs:5:22
+
+error: could not find defining uses
+  --> $DIR/generic_nondefining_use.rs:5:1
    |
 LL | existential type Cmp<T>: 'static;
-   |                      ^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/existential_types/not_a_defining_use.rs b/src/test/ui/existential_types/not_a_defining_use.rs
new file mode 100644
index 0000000000000..3f81f5177d0a4
--- /dev/null
+++ b/src/test/ui/existential_types/not_a_defining_use.rs
@@ -0,0 +1,40 @@
+#![feature(existential_type)]
+
+use std::fmt::Debug;
+
+fn main() {}
+
+existential type Two<T, U>: Debug;
+
+fn two<T: Debug>(t: T) -> Two<T, u32> {
+    //~^ ERROR defining existential type use does not fully define existential type
+    (t, 4i8)
+}
+
+fn three<T: Debug, U>(t: T) -> Two<T, U> {
+    (t, 5i8)
+}
+
+trait Bar {
+    type Blub: Debug;
+    const FOO: Self::Blub;
+}
+
+impl Bar for u32 {
+    type Blub = i32;
+    const FOO: i32 = 42;
+}
+
+// this should work! But it requires `two` and `three` not to be defining uses,
+// just restricting uses
+fn four<T: Debug, U: Bar>(t: T) -> Two<T, U> { //~ concrete type differs from previous
+    (t, <U as Bar>::FOO)
+}
+
+fn is_sync<T: Sync>() {}
+
+fn asdfl() {
+    //FIXME(oli-obk): these currently cause cycle errors
+    //is_sync::<Two<i32, u32>>();
+    //is_sync::<Two<i32, *const i32>>();
+}
diff --git a/src/test/ui/existential_types/not_a_defining_use.stderr b/src/test/ui/existential_types/not_a_defining_use.stderr
new file mode 100644
index 0000000000000..288a32fc14edd
--- /dev/null
+++ b/src/test/ui/existential_types/not_a_defining_use.stderr
@@ -0,0 +1,27 @@
+error: defining existential type use does not fully define existential type
+  --> $DIR/not_a_defining_use.rs:9:1
+   |
+LL | / fn two<T: Debug>(t: T) -> Two<T, u32> {
+LL | |     //~^ ERROR defining existential type use does not fully define existential type
+LL | |     (t, 4i8)
+LL | | }
+   | |_^
+
+error: concrete type differs from previous defining existential type use
+  --> $DIR/not_a_defining_use.rs:30:1
+   |
+LL | / fn four<T: Debug, U: Bar>(t: T) -> Two<T, U> { //~ concrete type differs from previous
+LL | |     (t, <U as Bar>::FOO)
+LL | | }
+   | |_^ expected `(T, i8)`, got `(T, <U as Bar>::Blub)`
+   |
+note: previous use here
+  --> $DIR/not_a_defining_use.rs:14:1
+   |
+LL | / fn three<T: Debug, U>(t: T) -> Two<T, U> {
+LL | |     (t, 5i8)
+LL | | }
+   | |_^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/existential_types/unused_generic_param.rs b/src/test/ui/existential_types/unused_generic_param.rs
index bd7b343b402f5..7af6508788129 100644
--- a/src/test/ui/existential_types/unused_generic_param.rs
+++ b/src/test/ui/existential_types/unused_generic_param.rs
@@ -1,15 +1,18 @@
+// compile-pass
 #![feature(existential_type)]
 
 fn main() {
 }
 
-existential type PartiallyDefined<T>: 'static; //~ `T` is unused
+// test that unused generic parameters are ok
+existential type PartiallyDefined<T>: 'static;
 
 fn partially_defined<T: std::fmt::Debug>(_: T) -> PartiallyDefined<T> {
     4u32
 }
 
-existential type PartiallyDefined2<T>: 'static; //~ `T` is unused
+// test that unused generic parameters are ok
+existential type PartiallyDefined2<T>: 'static;
 
 fn partially_defined2<T: std::fmt::Debug>(_: T) -> PartiallyDefined2<T> {
     4u32
diff --git a/src/test/ui/existential_types/unused_generic_param.stderr b/src/test/ui/existential_types/unused_generic_param.stderr
deleted file mode 100644
index 348aed3c43914..0000000000000
--- a/src/test/ui/existential_types/unused_generic_param.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error[E0091]: type parameter `T` is unused
-  --> $DIR/unused_generic_param.rs:6:35
-   |
-LL | existential type PartiallyDefined<T>: 'static; //~ `T` is unused
-   |                                   ^ unused type parameter
-
-error[E0091]: type parameter `T` is unused
-  --> $DIR/unused_generic_param.rs:12:36
-   |
-LL | existential type PartiallyDefined2<T>: 'static; //~ `T` is unused
-   |                                    ^ unused type parameter
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0091`.
diff --git a/src/test/ui/feature-gate-optimize_attribute.rs b/src/test/ui/feature-gate-optimize_attribute.rs
new file mode 100644
index 0000000000000..c1f7510014187
--- /dev/null
+++ b/src/test/ui/feature-gate-optimize_attribute.rs
@@ -0,0 +1,18 @@
+#![crate_type="rlib"]
+#![optimize(speed)] //~ ERROR #54882
+
+#[optimize(size)] //~ ERROR #54882
+mod module {
+
+#[optimize(size)] //~ ERROR #54882
+fn size() {}
+
+#[optimize(speed)] //~ ERROR #54882
+fn speed() {}
+
+#[optimize(banana)]
+//~^ ERROR #54882
+//~| ERROR E0722
+fn not_known() {}
+
+}
diff --git a/src/test/ui/feature-gate-optimize_attribute.stderr b/src/test/ui/feature-gate-optimize_attribute.stderr
new file mode 100644
index 0000000000000..ddd4c457d731b
--- /dev/null
+++ b/src/test/ui/feature-gate-optimize_attribute.stderr
@@ -0,0 +1,50 @@
+error[E0658]: #[optimize] attribute is an unstable feature (see issue #54882)
+  --> $DIR/feature-gate-optimize_attribute.rs:7:1
+   |
+LL | #[optimize(size)] //~ ERROR #54882
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(optimize_attribute)] to the crate attributes to enable
+
+error[E0658]: #[optimize] attribute is an unstable feature (see issue #54882)
+  --> $DIR/feature-gate-optimize_attribute.rs:10:1
+   |
+LL | #[optimize(speed)] //~ ERROR #54882
+   | ^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(optimize_attribute)] to the crate attributes to enable
+
+error[E0658]: #[optimize] attribute is an unstable feature (see issue #54882)
+  --> $DIR/feature-gate-optimize_attribute.rs:13:1
+   |
+LL | #[optimize(banana)]
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(optimize_attribute)] to the crate attributes to enable
+
+error[E0658]: #[optimize] attribute is an unstable feature (see issue #54882)
+  --> $DIR/feature-gate-optimize_attribute.rs:4:1
+   |
+LL | #[optimize(size)] //~ ERROR #54882
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(optimize_attribute)] to the crate attributes to enable
+
+error[E0658]: #[optimize] attribute is an unstable feature (see issue #54882)
+  --> $DIR/feature-gate-optimize_attribute.rs:2:1
+   |
+LL | #![optimize(speed)] //~ ERROR #54882
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(optimize_attribute)] to the crate attributes to enable
+
+error[E0722]: invalid argument
+  --> $DIR/feature-gate-optimize_attribute.rs:13:12
+   |
+LL | #[optimize(banana)]
+   |            ^^^^^^
+
+error: aborting due to 6 previous errors
+
+Some errors occurred: E0658, E0722.
+For more information about an error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs
new file mode 100644
index 0000000000000..92844f9306d28
--- /dev/null
+++ b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.rs
@@ -0,0 +1,6 @@
+//~ ERROR kind="static-nobundle" is feature gated
+// Test the behavior of rustc when non-existent library is statically linked
+
+// compile-flags: -l static-nobundle=nonexistent
+
+fn main() {}
diff --git a/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr
new file mode 100644
index 0000000000000..419c21901a02f
--- /dev/null
+++ b/src/test/ui/feature-gate/feature-gate-static-nobundle-2.stderr
@@ -0,0 +1,7 @@
+error[E0658]: kind="static-nobundle" is feature gated (see issue #37403)
+   |
+   = help: add #![feature(static_nobundle)] to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/auxiliary/pub_dep.rs b/src/test/ui/feature-gates/auxiliary/pub_dep.rs
new file mode 100644
index 0000000000000..3ebafd953addf
--- /dev/null
+++ b/src/test/ui/feature-gates/auxiliary/pub_dep.rs
@@ -0,0 +1 @@
+pub struct PubType;
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.rs b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.rs
index cf320b2747c36..ee48f9516299a 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.rs
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.rs
@@ -5,7 +5,7 @@
 macro_rules! bar {
     () => {
         // more layers don't help:
-        #[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
+        #[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
         macro_rules! baz {
             () => {}
         }
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.stderr b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.stderr
index 7cdf743b279c2..802c74239d719 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.stderr
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-nested-macro.stderr
@@ -1,8 +1,8 @@
 error[E0658]: allow_internal_unstable side-steps feature gating and stability checks
   --> $DIR/feature-gate-allow-internal-unstable-nested-macro.rs:8:9
    |
-LL |         #[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |         #[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 ...
 LL | bar!();
    | ------- in this macro invocation
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.rs b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.rs
index c9ea6c338b5cc..ede969097d5ae 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.rs
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.rs
@@ -1,7 +1,7 @@
 // checks that this attribute is caught on non-macro items.
 // this needs a different test since this is done after expansion
 
-#[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
+#[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
 struct S;
 
 fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.stderr b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.stderr
index 485c00ad42bd6..d619f1e3239ca 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.stderr
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable-struct.stderr
@@ -1,8 +1,8 @@
 error[E0658]: allow_internal_unstable side-steps feature gating and stability checks
   --> $DIR/feature-gate-allow-internal-unstable-struct.rs:4:1
    |
-LL | #[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(allow_internal_unstable)] to the crate attributes to enable
 
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.rs b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.rs
index bea60fc012e3f..0a1b6acd9bff2 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.rs
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.rs
@@ -1,6 +1,6 @@
 #![allow(unused_macros)]
 
-#[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
+#[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
 macro_rules! foo {
     () => {}
 }
diff --git a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.stderr b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.stderr
index 0533d071de3ac..aa4f6648c4fbd 100644
--- a/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.stderr
+++ b/src/test/ui/feature-gates/feature-gate-allow-internal-unstable.stderr
@@ -1,8 +1,8 @@
 error[E0658]: allow_internal_unstable side-steps feature gating and stability checks
   --> $DIR/feature-gate-allow-internal-unstable.rs:3:1
    |
-LL | #[allow_internal_unstable] //~ ERROR allow_internal_unstable side-steps
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #[allow_internal_unstable()] //~ ERROR allow_internal_unstable side-steps
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(allow_internal_unstable)] to the crate attributes to enable
 
diff --git a/src/test/ui/feature-gates/feature-gate-const_generics.rs b/src/test/ui/feature-gates/feature-gate-const_generics.rs
new file mode 100644
index 0000000000000..907e00b11e556
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-const_generics.rs
@@ -0,0 +1,7 @@
+fn foo<const X: ()>() {} //~ ERROR const generics are unstable
+//~^ const generics in any position are currently unsupported
+
+struct Foo<const X: usize>([(); X]); //~ ERROR const generics are unstable
+//~^ const generics in any position are currently unsupported
+
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-const_generics.stderr b/src/test/ui/feature-gates/feature-gate-const_generics.stderr
new file mode 100644
index 0000000000000..3ab1aa2367f1c
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-const_generics.stderr
@@ -0,0 +1,31 @@
+error[E0658]: const generics are unstable (see issue #44580)
+  --> $DIR/feature-gate-const_generics.rs:1:14
+   |
+LL | fn foo<const X: ()>() {} //~ ERROR const generics are unstable
+   |              ^
+   |
+   = help: add #![feature(const_generics)] to the crate attributes to enable
+
+error[E0658]: const generics are unstable (see issue #44580)
+  --> $DIR/feature-gate-const_generics.rs:4:18
+   |
+LL | struct Foo<const X: usize>([(); X]); //~ ERROR const generics are unstable
+   |                  ^
+   |
+   = help: add #![feature(const_generics)] to the crate attributes to enable
+
+error: const generics in any position are currently unsupported
+  --> $DIR/feature-gate-const_generics.rs:1:14
+   |
+LL | fn foo<const X: ()>() {} //~ ERROR const generics are unstable
+   |              ^
+
+error: const generics in any position are currently unsupported
+  --> $DIR/feature-gate-const_generics.rs:4:18
+   |
+LL | struct Foo<const X: usize>([(); X]); //~ ERROR const generics are unstable
+   |                  ^
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-extern_crate_self.rs b/src/test/ui/feature-gates/feature-gate-extern_crate_self.rs
deleted file mode 100644
index 2161932c2f6aa..0000000000000
--- a/src/test/ui/feature-gates/feature-gate-extern_crate_self.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-extern crate self as foo; //~ ERROR `extern crate self` is unstable
-
-fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-extern_crate_self.stderr b/src/test/ui/feature-gates/feature-gate-extern_crate_self.stderr
deleted file mode 100644
index 530015b2cb712..0000000000000
--- a/src/test/ui/feature-gates/feature-gate-extern_crate_self.stderr
+++ /dev/null
@@ -1,11 +0,0 @@
-error[E0658]: `extern crate self` is unstable (see issue #56409)
-  --> $DIR/feature-gate-extern_crate_self.rs:1:1
-   |
-LL | extern crate self as foo; //~ ERROR `extern crate self` is unstable
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: add #![feature(extern_crate_self)] to the crate attributes to enable
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-is_sorted.rs b/src/test/ui/feature-gates/feature-gate-is_sorted.rs
new file mode 100644
index 0000000000000..078ecc577610b
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-is_sorted.rs
@@ -0,0 +1,13 @@
+fn main() {
+    // Assert `Iterator` methods are feature gated
+    assert!([1, 2, 2, 9].iter().is_sorted());
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
+    assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
+
+    // Assert `[T]` methods are feature gated
+    assert!([1, 2, 2, 9].is_sorted());
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
+    assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
+}
diff --git a/src/test/ui/feature-gates/feature-gate-is_sorted.stderr b/src/test/ui/feature-gates/feature-gate-is_sorted.stderr
new file mode 100644
index 0000000000000..8230c1e3a38dc
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-is_sorted.stderr
@@ -0,0 +1,35 @@
+error[E0658]: use of unstable library feature 'is_sorted': new API (see issue #53485)
+  --> $DIR/feature-gate-is_sorted.rs:3:33
+   |
+LL |     assert!([1, 2, 2, 9].iter().is_sorted());
+   |                                 ^^^^^^^^^
+   |
+   = help: add #![feature(is_sorted)] to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'is_sorted': new API (see issue #53485)
+  --> $DIR/feature-gate-is_sorted.rs:5:39
+   |
+LL |     assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
+   |                                       ^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(is_sorted)] to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'is_sorted': new API (see issue #53485)
+  --> $DIR/feature-gate-is_sorted.rs:9:26
+   |
+LL |     assert!([1, 2, 2, 9].is_sorted());
+   |                          ^^^^^^^^^
+   |
+   = help: add #![feature(is_sorted)] to the crate attributes to enable
+
+error[E0658]: use of unstable library feature 'is_sorted': new API (see issue #53485)
+  --> $DIR/feature-gate-is_sorted.rs:11:32
+   |
+LL |     assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
+   |                                ^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(is_sorted)] to the crate attributes to enable
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-public_private_dependencies.rs b/src/test/ui/feature-gates/feature-gate-public_private_dependencies.rs
new file mode 100644
index 0000000000000..b8fb4b8dc19da
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-public_private_dependencies.rs
@@ -0,0 +1,20 @@
+// This test is different from other feature gate tests.
+// Instead of checking that an error occurs without the feature gate,
+// it checks that *no* errors/warnings occurs without the feature gate.
+// This is due to the fact that 'public_private_dependencies' just enables
+// a lint, so disabling it shouldn't cause any code to stop compiling.
+
+// run-pass
+// aux-build:pub_dep.rs
+
+// Without ![feature(public_private_dependencies)],
+// this should do nothing/
+#![deny(exported_private_dependencies)]
+
+extern crate pub_dep;
+
+pub struct Foo {
+    pub field: pub_dep::PubType
+}
+
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-repr_align_enum.rs b/src/test/ui/feature-gates/feature-gate-repr_align_enum.rs
new file mode 100644
index 0000000000000..f8e68a9de015b
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-repr_align_enum.rs
@@ -0,0 +1,10 @@
+#[repr(align(16))]
+struct Foo(u64);
+
+#[repr(align(8))] //~ ERROR `#[repr(align(x))]` on enums is experimental (see issue #57996)
+enum Bar {
+    Foo { foo: Foo },
+    Baz,
+}
+
+fn main() { }
diff --git a/src/test/ui/feature-gates/feature-gate-repr_align_enum.stderr b/src/test/ui/feature-gates/feature-gate-repr_align_enum.stderr
new file mode 100644
index 0000000000000..6def25f965118
--- /dev/null
+++ b/src/test/ui/feature-gates/feature-gate-repr_align_enum.stderr
@@ -0,0 +1,11 @@
+error[E0658]: `#[repr(align(x))]` on enums is experimental (see issue #57996)
+  --> $DIR/feature-gate-repr_align_enum.rs:4:1
+   |
+LL | #[repr(align(8))] //~ ERROR `#[repr(align(x))]` on enums is experimental (see issue #57996)
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(repr_align_enum)] to the crate attributes to enable
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.rs b/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.rs
index 2b23388fdc96d..f7ff3eb3ac9ff 100644
--- a/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.rs
+++ b/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.rs
@@ -5,4 +5,4 @@
 #[rustc_variance] //~ ERROR the `#[rustc_variance]` attribute is just used for rustc unit tests and will never be stable
 #[rustc_error] //~ ERROR the `#[rustc_error]` attribute is just used for rustc unit tests and will never be stable
 
-fn main() {} //~ ERROR []
+fn main() {}
diff --git a/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.stderr b/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.stderr
index 31e24f5b99f1e..2b90699384b48 100644
--- a/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.stderr
+++ b/src/test/ui/feature-gates/feature-gate-rustc-attrs-1.stderr
@@ -14,13 +14,6 @@ LL | #[rustc_error] //~ ERROR the `#[rustc_error]` attribute is just used for ru
    |
    = help: add #![feature(rustc_attrs)] to the crate attributes to enable
 
-error[E0208]: []
-  --> $DIR/feature-gate-rustc-attrs-1.rs:8:1
-   |
-LL | fn main() {} //~ ERROR []
-   | ^^^^^^^^^^^^
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors occurred: E0208, E0658.
-For more information about an error, try `rustc --explain E0208`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr b/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
index 9a33d29766fb9..47bb5e475b473 100644
--- a/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
+++ b/src/test/ui/fully-qualified-type/fully-qualified-type-name2.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/fully-qualified-type-name2.rs:12:12
    |
+LL | fn bar(x: x::Foo) -> y::Foo {
+   |                      ------ expected `y::Foo` because of return type
 LL |     return x;
    |            ^ expected enum `y::Foo`, found enum `x::Foo`
    |
diff --git a/src/test/ui/fully-qualified-type/fully-qualified-type-name4.stderr b/src/test/ui/fully-qualified-type/fully-qualified-type-name4.stderr
index f03aaa67edbb8..b341879ab919a 100644
--- a/src/test/ui/fully-qualified-type/fully-qualified-type-name4.stderr
+++ b/src/test/ui/fully-qualified-type/fully-qualified-type-name4.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/fully-qualified-type-name4.rs:6:12
    |
+LL | fn bar(x: usize) -> Option<usize> {
+   |                     ------------- expected `std::option::Option<usize>` because of return type
 LL |     return x;
    |            ^ expected enum `std::option::Option`, found usize
    |
diff --git a/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs b/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs
index 00606af904835..7ae53020fe011 100644
--- a/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs
+++ b/src/test/ui/functional-struct-update/functional-struct-update-respects-privacy.rs
@@ -6,12 +6,12 @@ use self::foo::S;
 mod foo {
     use std::cell::{UnsafeCell};
 
-    static mut count : UnsafeCell<u64> = UnsafeCell::new(1);
+    static mut COUNT : UnsafeCell<u64> = UnsafeCell::new(1);
 
     pub struct S { pub a: u8, pub b: String, secret_uid: u64 }
 
     pub fn make_secrets(a: u8, b: String) -> S {
-        let val = unsafe { let p = count.get(); let val = *p; *p = val + 1; val };
+        let val = unsafe { let p = COUNT.get(); let val = *p; *p = val + 1; val };
         println!("creating {}, uid {}", b, val);
         S { a: a, b: b, secret_uid: val }
     }
diff --git a/src/test/ui/generator/auto-trait-regions.stderr b/src/test/ui/generator/auto-trait-regions.stderr
index 1b4dfe2df1c0c..92f92e2a32a36 100644
--- a/src/test/ui/generator/auto-trait-regions.stderr
+++ b/src/test/ui/generator/auto-trait-regions.stderr
@@ -4,8 +4,8 @@ error: implementation of `Foo` is not general enough
 LL |     assert_foo(gen);
    |     ^^^^^^^^^^
    |
-   = note: `&'0 OnlyFooIfStaticRef` must implement `Foo` for any lifetime `'0`
-   = note: but `&'1 OnlyFooIfStaticRef` only implements `Foo` for the lifetime `'1`
+   = note: `Foo` would have to be implemented for the type `&'0 OnlyFooIfStaticRef`, for any lifetime `'0`
+   = note: but `Foo` is actually implemented for the type `&'1 OnlyFooIfStaticRef`, for some specific lifetime `'1`
 
 error: implementation of `Foo` is not general enough
   --> $DIR/auto-trait-regions.rs:48:5
@@ -13,8 +13,8 @@ error: implementation of `Foo` is not general enough
 LL |     assert_foo(gen);
    |     ^^^^^^^^^^
    |
-   = note: `A<'0, '1>` must implement `Foo` for any two lifetimes `'0` and `'1`
-   = note: but `A<'_, '2>` only implements `Foo` for the lifetime `'2`
+   = note: `Foo` would have to be implemented for the type `A<'0, '1>`, for any two lifetimes `'0` and `'1`
+   = note: but `Foo` is actually implemented for the type `A<'_, '2>`, for some specific lifetime `'2`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/generator/borrowing.nll.stderr b/src/test/ui/generator/borrowing.nll.stderr
index af6ec4941d890..3c9221d28e74d 100644
--- a/src/test/ui/generator/borrowing.nll.stderr
+++ b/src/test/ui/generator/borrowing.nll.stderr
@@ -1,12 +1,12 @@
 error[E0597]: `a` does not live long enough
-  --> $DIR/borrowing.rs:8:29
+  --> $DIR/borrowing.rs:9:33
    |
-LL |         unsafe { (|| yield &a).resume() }
-   |                  -----------^-
-   |                  ||         |
-   |                  ||         borrowed value does not live long enough
-   |                  |value captured here by generator
-   |                  a temporary with access to the borrow is created here ...
+LL |         Pin::new(&mut || yield &a).resume()
+   |                       ----------^
+   |                       |         |
+   |                       |         borrowed value does not live long enough
+   |                       value captured here by generator
+   |                       a temporary with access to the borrow is created here ...
 LL |         //~^ ERROR: `a` does not live long enough
 LL |     };
    |     -- ... and the borrow might be used here, when that temporary is dropped and runs the destructor for generator
@@ -16,7 +16,7 @@ LL |     };
    = note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
 
 error[E0597]: `a` does not live long enough
-  --> $DIR/borrowing.rs:15:20
+  --> $DIR/borrowing.rs:16:20
    |
 LL |     let _b = {
    |         -- borrow later stored here
diff --git a/src/test/ui/generator/borrowing.rs b/src/test/ui/generator/borrowing.rs
index 88a0cf9a77a54..9f8fc7483f64d 100644
--- a/src/test/ui/generator/borrowing.rs
+++ b/src/test/ui/generator/borrowing.rs
@@ -1,11 +1,12 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
     let _b = {
         let a = 3;
-        unsafe { (|| yield &a).resume() }
+        Pin::new(&mut || yield &a).resume()
         //~^ ERROR: `a` does not live long enough
     };
 
diff --git a/src/test/ui/generator/borrowing.stderr b/src/test/ui/generator/borrowing.stderr
index 3f5d32e1c3358..169e4a8561c1d 100644
--- a/src/test/ui/generator/borrowing.stderr
+++ b/src/test/ui/generator/borrowing.stderr
@@ -1,10 +1,10 @@
 error[E0597]: `a` does not live long enough
-  --> $DIR/borrowing.rs:8:29
+  --> $DIR/borrowing.rs:9:33
    |
-LL |         unsafe { (|| yield &a).resume() }
-   |                   --        ^ borrowed value does not live long enough
-   |                   |
-   |                   capture occurs here
+LL |         Pin::new(&mut || yield &a).resume()
+   |                       --        ^ borrowed value does not live long enough
+   |                       |
+   |                       capture occurs here
 LL |         //~^ ERROR: `a` does not live long enough
 LL |     };
    |     - borrowed value only lives until here
@@ -13,7 +13,7 @@ LL | }
    | - borrowed value needs to live until here
 
 error[E0597]: `a` does not live long enough
-  --> $DIR/borrowing.rs:15:20
+  --> $DIR/borrowing.rs:16:20
    |
 LL |         || {
    |         -- capture occurs here
diff --git a/src/test/ui/generator/dropck.nll.stderr b/src/test/ui/generator/dropck.nll.stderr
index 1f6b7db2bd853..a90a47fe9aa01 100644
--- a/src/test/ui/generator/dropck.nll.stderr
+++ b/src/test/ui/generator/dropck.nll.stderr
@@ -1,5 +1,5 @@
 error[E0597]: `*cell` does not live long enough
-  --> $DIR/dropck.rs:9:40
+  --> $DIR/dropck.rs:10:40
    |
 LL |     let ref_ = Box::leak(Box::new(Some(cell.borrow_mut())));
    |                                        ^^^^ borrowed value does not live long enough
@@ -13,7 +13,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are defined
 
 error[E0597]: `ref_` does not live long enough
-  --> $DIR/dropck.rs:14:18
+  --> $DIR/dropck.rs:15:18
    |
 LL |     gen = || {
    |           -- value captured here by generator
diff --git a/src/test/ui/generator/dropck.rs b/src/test/ui/generator/dropck.rs
index 1b0c1ebe517b4..65c61fbaac4e2 100644
--- a/src/test/ui/generator/dropck.rs
+++ b/src/test/ui/generator/dropck.rs
@@ -2,6 +2,7 @@
 
 use std::cell::RefCell;
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
     let (mut gen, cell);
@@ -14,6 +15,6 @@ fn main() {
         let _d = ref_.take(); //~ ERROR `ref_` does not live long enough
         yield;
     };
-    unsafe { gen.resume(); }
+    Pin::new(&mut gen).resume();
     // drops the RefCell and then the Ref, leading to use-after-free
 }
diff --git a/src/test/ui/generator/dropck.stderr b/src/test/ui/generator/dropck.stderr
index 281c9647bc3e1..fdaa5cfbae3e6 100644
--- a/src/test/ui/generator/dropck.stderr
+++ b/src/test/ui/generator/dropck.stderr
@@ -1,5 +1,5 @@
 error[E0597]: `*cell` does not live long enough
-  --> $DIR/dropck.rs:9:40
+  --> $DIR/dropck.rs:10:40
    |
 LL |     let ref_ = Box::leak(Box::new(Some(cell.borrow_mut())));
    |                                        ^^^^ borrowed value does not live long enough
@@ -10,7 +10,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `ref_` does not live long enough
-  --> $DIR/dropck.rs:14:18
+  --> $DIR/dropck.rs:15:18
    |
 LL |     gen = || {
    |           -- capture occurs here
diff --git a/src/test/ui/generator/generator-region-requirements.ast.stderr b/src/test/ui/generator/generator-region-requirements.ast.stderr
index 6a423aea7eceb..8a96d187f6b1c 100644
--- a/src/test/ui/generator/generator-region-requirements.ast.stderr
+++ b/src/test/ui/generator/generator-region-requirements.ast.stderr
@@ -1,5 +1,5 @@
 error[E0621]: explicit lifetime required in the type of `x`
-  --> $DIR/generator-region-requirements.rs:15:51
+  --> $DIR/generator-region-requirements.rs:16:51
    |
 LL | fn dangle(x: &mut i32) -> &'static mut i32 {
    |              -------- help: add explicit lifetime `'static` to the type of `x`: `&'static mut i32`
diff --git a/src/test/ui/generator/generator-region-requirements.nll.stderr b/src/test/ui/generator/generator-region-requirements.nll.stderr
index 6a423aea7eceb..8a96d187f6b1c 100644
--- a/src/test/ui/generator/generator-region-requirements.nll.stderr
+++ b/src/test/ui/generator/generator-region-requirements.nll.stderr
@@ -1,5 +1,5 @@
 error[E0621]: explicit lifetime required in the type of `x`
-  --> $DIR/generator-region-requirements.rs:15:51
+  --> $DIR/generator-region-requirements.rs:16:51
    |
 LL | fn dangle(x: &mut i32) -> &'static mut i32 {
    |              -------- help: add explicit lifetime `'static` to the type of `x`: `&'static mut i32`
diff --git a/src/test/ui/generator/generator-region-requirements.rs b/src/test/ui/generator/generator-region-requirements.rs
index 2cda483b6a1c2..9738f6c3932ed 100644
--- a/src/test/ui/generator/generator-region-requirements.rs
+++ b/src/test/ui/generator/generator-region-requirements.rs
@@ -4,6 +4,7 @@
 #![feature(generators, generator_trait)]
 #![cfg_attr(nll, feature(nll))]
 use std::ops::{Generator, GeneratorState};
+use std::pin::Pin;
 
 fn dangle(x: &mut i32) -> &'static mut i32 {
     let mut g = || {
@@ -11,7 +12,7 @@ fn dangle(x: &mut i32) -> &'static mut i32 {
         x
     };
     loop {
-        match unsafe { g.resume() } {
+        match Pin::new(&mut g).resume() {
             GeneratorState::Complete(c) => return c,
 //[nll]~^ ERROR explicit lifetime required
 //[ast]~^^ ERROR explicit lifetime required
diff --git a/src/test/ui/generator/ref-escapes-but-not-over-yield.nll.stderr b/src/test/ui/generator/ref-escapes-but-not-over-yield.nll.stderr
index 72a4654dec8b2..01eea627351fb 100644
--- a/src/test/ui/generator/ref-escapes-but-not-over-yield.nll.stderr
+++ b/src/test/ui/generator/ref-escapes-but-not-over-yield.nll.stderr
@@ -1,5 +1,5 @@
 error[E0521]: borrowed data escapes outside of generator
-  --> $DIR/ref-escapes-but-not-over-yield.rs:14:9
+  --> $DIR/ref-escapes-but-not-over-yield.rs:11:9
    |
 LL |     let mut a = &3;
    |         ----- `a` is declared here, outside of the generator body
diff --git a/src/test/ui/generator/ref-escapes-but-not-over-yield.rs b/src/test/ui/generator/ref-escapes-but-not-over-yield.rs
index 332e074e9fe64..8c576581ad8dd 100644
--- a/src/test/ui/generator/ref-escapes-but-not-over-yield.rs
+++ b/src/test/ui/generator/ref-escapes-but-not-over-yield.rs
@@ -1,7 +1,4 @@
-#![feature(generators, generator_trait)]
-
-use std::ops::{GeneratorState, Generator};
-use std::cell::Cell;
+#![feature(generators)]
 
 fn foo(x: &i32) {
     // In this case, a reference to `b` escapes the generator, but not
diff --git a/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr b/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
index e1d718e847f8f..29299b2405a00 100644
--- a/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
+++ b/src/test/ui/generator/ref-escapes-but-not-over-yield.stderr
@@ -1,5 +1,5 @@
 error[E0597]: `b` does not live long enough
-  --> $DIR/ref-escapes-but-not-over-yield.rs:14:14
+  --> $DIR/ref-escapes-but-not-over-yield.rs:11:14
    |
 LL |         a = &b;
    |              ^ borrowed value does not live long enough
diff --git a/src/test/ui/generator/sized-yield.rs b/src/test/ui/generator/sized-yield.rs
index e34731a4406d9..f64849b3149b8 100644
--- a/src/test/ui/generator/sized-yield.rs
+++ b/src/test/ui/generator/sized-yield.rs
@@ -1,6 +1,7 @@
 #![feature(generators, generator_trait)]
 
 use std::ops::Generator;
+use std::pin::Pin;
 
 fn main() {
    let s = String::from("foo");
@@ -8,6 +9,6 @@ fn main() {
    //~^ ERROR the size for values of type
        yield s[..];
    };
-   unsafe { gen.resume(); }
+   Pin::new(&mut gen).resume();
    //~^ ERROR the size for values of type
 }
diff --git a/src/test/ui/generator/sized-yield.stderr b/src/test/ui/generator/sized-yield.stderr
index 4f59f2c1c6ab3..c98f42e62168e 100644
--- a/src/test/ui/generator/sized-yield.stderr
+++ b/src/test/ui/generator/sized-yield.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the size for values of type `str` cannot be known at compilation time
-  --> $DIR/sized-yield.rs:7:26
+  --> $DIR/sized-yield.rs:8:26
    |
 LL |      let mut gen = move || {
    |  __________________________^
@@ -13,10 +13,10 @@ LL | |    };
    = note: the yield type of a generator must have a statically known size
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time
-  --> $DIR/sized-yield.rs:11:17
+  --> $DIR/sized-yield.rs:12:23
    |
-LL |    unsafe { gen.resume(); }
-   |                 ^^^^^^ doesn't have a size known at compile-time
+LL |    Pin::new(&mut gen).resume();
+   |                       ^^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `std::marker::Sized` is not implemented for `str`
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
diff --git a/src/test/ui/generator/static-not-unpin.rs b/src/test/ui/generator/static-not-unpin.rs
new file mode 100644
index 0000000000000..b271e982fb420
--- /dev/null
+++ b/src/test/ui/generator/static-not-unpin.rs
@@ -0,0 +1,15 @@
+#![feature(generators)]
+
+// normalize-stderr-test "std::pin::Unpin" -> "std::marker::Unpin"
+
+use std::marker::Unpin;
+
+fn assert_unpin<T: Unpin>(_: T) {
+}
+
+fn main() {
+    let mut generator = static || {
+        yield;
+    };
+    assert_unpin(generator); //~ ERROR std::marker::Unpin` is not satisfied
+}
diff --git a/src/test/ui/generator/static-not-unpin.stderr b/src/test/ui/generator/static-not-unpin.stderr
new file mode 100644
index 0000000000000..caf92f0ec693e
--- /dev/null
+++ b/src/test/ui/generator/static-not-unpin.stderr
@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `[static generator@$DIR/static-not-unpin.rs:11:25: 13:6 _]: std::marker::Unpin` is not satisfied
+  --> $DIR/static-not-unpin.rs:14:5
+   |
+LL |     assert_unpin(generator); //~ ERROR std::marker::Unpin` is not satisfied
+   |     ^^^^^^^^^^^^ the trait `std::marker::Unpin` is not implemented for `[static generator@$DIR/static-not-unpin.rs:11:25: 13:6 _]`
+   |
+note: required by `assert_unpin`
+  --> $DIR/static-not-unpin.rs:7:1
+   |
+LL | fn assert_unpin<T: Unpin>(_: T) {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generator/yield-while-iterating.nll.stderr b/src/test/ui/generator/yield-while-iterating.nll.stderr
index bcbd68ab85d5c..2dc12f843b220 100644
--- a/src/test/ui/generator/yield-while-iterating.nll.stderr
+++ b/src/test/ui/generator/yield-while-iterating.nll.stderr
@@ -1,5 +1,5 @@
 error[E0626]: borrow may still be in use when generator yields
-  --> $DIR/yield-while-iterating.rs:12:18
+  --> $DIR/yield-while-iterating.rs:13:18
    |
 LL |         for p in &x { //~ ERROR
    |                  ^^
@@ -7,7 +7,7 @@ LL |             yield();
    |             ------- possible yield occurs here
 
 error[E0502]: cannot borrow `x` as immutable because it is also borrowed as mutable
-  --> $DIR/yield-while-iterating.rs:57:20
+  --> $DIR/yield-while-iterating.rs:58:20
    |
 LL |     let mut b = || {
    |                 -- mutable borrow occurs here
@@ -16,8 +16,8 @@ LL |         for p in &mut x {
 ...
 LL |     println!("{}", x[0]); //~ ERROR
    |                    ^ immutable borrow occurs here
-LL |     b.resume();
-   |     - mutable borrow later used here
+LL |     Pin::new(&mut b).resume();
+   |              ------ mutable borrow later used here
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/generator/yield-while-iterating.rs b/src/test/ui/generator/yield-while-iterating.rs
index b0966d2e921b7..e42781d1279e7 100644
--- a/src/test/ui/generator/yield-while-iterating.rs
+++ b/src/test/ui/generator/yield-while-iterating.rs
@@ -2,6 +2,7 @@
 
 use std::ops::{GeneratorState, Generator};
 use std::cell::Cell;
+use std::pin::Pin;
 
 fn yield_during_iter_owned_data(x: Vec<i32>) {
     // The generator owns `x`, so we error out when yielding with a
@@ -33,7 +34,7 @@ fn yield_during_iter_borrowed_slice_2() {
     println!("{:?}", x);
 }
 
-unsafe fn yield_during_iter_borrowed_slice_3() {
+fn yield_during_iter_borrowed_slice_3() {
     // OK to take a mutable ref to `x` and yield
     // up pointers from it:
     let mut x = vec![22_i32];
@@ -42,10 +43,10 @@ unsafe fn yield_during_iter_borrowed_slice_3() {
             yield p;
         }
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn yield_during_iter_borrowed_slice_4() {
+fn yield_during_iter_borrowed_slice_4() {
     // ...but not OK to do that while reading
     // from `x` too
     let mut x = vec![22_i32];
@@ -55,10 +56,10 @@ unsafe fn yield_during_iter_borrowed_slice_4() {
         }
     };
     println!("{}", x[0]); //~ ERROR
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn yield_during_range_iter() {
+fn yield_during_range_iter() {
     // Should be OK.
     let mut b = || {
         let v = vec![1,2,3];
@@ -68,7 +69,7 @@ unsafe fn yield_during_range_iter() {
             yield x;
         }
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
 fn main() { }
diff --git a/src/test/ui/generator/yield-while-iterating.stderr b/src/test/ui/generator/yield-while-iterating.stderr
index aa66047feb227..1e3e31470e9d6 100644
--- a/src/test/ui/generator/yield-while-iterating.stderr
+++ b/src/test/ui/generator/yield-while-iterating.stderr
@@ -1,5 +1,5 @@
 error[E0626]: borrow may still be in use when generator yields
-  --> $DIR/yield-while-iterating.rs:12:19
+  --> $DIR/yield-while-iterating.rs:13:19
    |
 LL |         for p in &x { //~ ERROR
    |                   ^
@@ -7,7 +7,7 @@ LL |             yield();
    |             ------- possible yield occurs here
 
 error[E0502]: cannot borrow `x` as immutable because it is also borrowed as mutable
-  --> $DIR/yield-while-iterating.rs:57:20
+  --> $DIR/yield-while-iterating.rs:58:20
    |
 LL |     let mut b = || {
    |                 -- mutable borrow occurs here
@@ -16,7 +16,7 @@ LL |         for p in &mut x {
 ...
 LL |     println!("{}", x[0]); //~ ERROR
    |                    ^ immutable borrow occurs here
-LL |     b.resume();
+LL |     Pin::new(&mut b).resume();
 LL | }
    | - mutable borrow ends here
 
diff --git a/src/test/ui/generator/yield-while-local-borrowed.rs b/src/test/ui/generator/yield-while-local-borrowed.rs
index a895f05b34cae..38061e71358c4 100644
--- a/src/test/ui/generator/yield-while-local-borrowed.rs
+++ b/src/test/ui/generator/yield-while-local-borrowed.rs
@@ -4,8 +4,9 @@
 
 use std::ops::{GeneratorState, Generator};
 use std::cell::Cell;
+use std::pin::Pin;
 
-unsafe fn borrow_local_inline() {
+fn borrow_local_inline() {
     // Not OK to yield with a borrow of a temporary.
     //
     // (This error occurs because the region shows up in the type of
@@ -17,10 +18,10 @@ unsafe fn borrow_local_inline() {
         yield();
         println!("{}", a);
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn borrow_local_inline_done() {
+fn borrow_local_inline_done() {
     // No error here -- `a` is not in scope at the point of `yield`.
     let mut b = move || {
         {
@@ -28,10 +29,10 @@ unsafe fn borrow_local_inline_done() {
         }
         yield();
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn borrow_local() {
+fn borrow_local() {
     // Not OK to yield with a borrow of a temporary.
     //
     // (This error occurs because the region shows up in the type of
@@ -46,7 +47,7 @@ unsafe fn borrow_local() {
             println!("{}", b);
         }
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
 fn main() { }
diff --git a/src/test/ui/generator/yield-while-local-borrowed.stderr b/src/test/ui/generator/yield-while-local-borrowed.stderr
index 765267a58b4a7..56f425b7e70a0 100644
--- a/src/test/ui/generator/yield-while-local-borrowed.stderr
+++ b/src/test/ui/generator/yield-while-local-borrowed.stderr
@@ -1,5 +1,5 @@
 error[E0626]: borrow may still be in use when generator yields (Ast)
-  --> $DIR/yield-while-local-borrowed.rs:14:22
+  --> $DIR/yield-while-local-borrowed.rs:15:22
    |
 LL |         let a = &mut 3;
    |                      ^
@@ -8,7 +8,7 @@ LL |         yield();
    |         ------- possible yield occurs here
 
 error[E0626]: borrow may still be in use when generator yields (Ast)
-  --> $DIR/yield-while-local-borrowed.rs:42:22
+  --> $DIR/yield-while-local-borrowed.rs:43:22
    |
 LL |             let b = &a;
    |                      ^
@@ -17,7 +17,7 @@ LL |             yield();
    |             ------- possible yield occurs here
 
 error[E0626]: borrow may still be in use when generator yields (Mir)
-  --> $DIR/yield-while-local-borrowed.rs:14:17
+  --> $DIR/yield-while-local-borrowed.rs:15:17
    |
 LL |         let a = &mut 3;
    |                 ^^^^^^
@@ -26,7 +26,7 @@ LL |         yield();
    |         ------- possible yield occurs here
 
 error[E0626]: borrow may still be in use when generator yields (Mir)
-  --> $DIR/yield-while-local-borrowed.rs:42:21
+  --> $DIR/yield-while-local-borrowed.rs:43:21
    |
 LL |             let b = &a;
    |                     ^^
diff --git a/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr b/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
index 9a99b6ad02518..d0d6a98301e59 100644
--- a/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
+++ b/src/test/ui/generator/yield-while-ref-reborrowed.nll.stderr
@@ -1,5 +1,5 @@
 error[E0501]: cannot borrow `x` as immutable because previous closure requires unique access
-  --> $DIR/yield-while-ref-reborrowed.rs:35:20
+  --> $DIR/yield-while-ref-reborrowed.rs:36:20
    |
 LL |     let mut b = || {
    |                 -- generator construction occurs here
@@ -8,8 +8,8 @@ LL |         let a = &mut *x;
 ...
 LL |     println!("{}", x); //~ ERROR
    |                    ^ second borrow occurs here
-LL |     b.resume();
-   |     - first borrow later used here
+LL |     Pin::new(&mut b).resume();
+   |              ------ first borrow later used here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/generator/yield-while-ref-reborrowed.rs b/src/test/ui/generator/yield-while-ref-reborrowed.rs
index 540907a421dfb..f54a4f468f6a0 100644
--- a/src/test/ui/generator/yield-while-ref-reborrowed.rs
+++ b/src/test/ui/generator/yield-while-ref-reborrowed.rs
@@ -2,8 +2,9 @@
 
 use std::ops::{GeneratorState, Generator};
 use std::cell::Cell;
+use std::pin::Pin;
 
-unsafe fn reborrow_shared_ref(x: &i32) {
+fn reborrow_shared_ref(x: &i32) {
     // This is OK -- we have a borrow live over the yield, but it's of
     // data that outlives the generator.
     let mut b = move || {
@@ -11,10 +12,10 @@ unsafe fn reborrow_shared_ref(x: &i32) {
         yield();
         println!("{}", a);
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn reborrow_mutable_ref(x: &mut i32) {
+fn reborrow_mutable_ref(x: &mut i32) {
     // This is OK -- we have a borrow live over the yield, but it's of
     // data that outlives the generator.
     let mut b = move || {
@@ -22,10 +23,10 @@ unsafe fn reborrow_mutable_ref(x: &mut i32) {
         yield();
         println!("{}", a);
     };
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
-unsafe fn reborrow_mutable_ref_2(x: &mut i32) {
+fn reborrow_mutable_ref_2(x: &mut i32) {
     // ...but not OK to go on using `x`.
     let mut b = || {
         let a = &mut *x;
@@ -33,7 +34,7 @@ unsafe fn reborrow_mutable_ref_2(x: &mut i32) {
         println!("{}", a);
     };
     println!("{}", x); //~ ERROR
-    b.resume();
+    Pin::new(&mut b).resume();
 }
 
 fn main() { }
diff --git a/src/test/ui/generator/yield-while-ref-reborrowed.stderr b/src/test/ui/generator/yield-while-ref-reborrowed.stderr
index d70ef189ebc9a..5c9de279c02d8 100644
--- a/src/test/ui/generator/yield-while-ref-reborrowed.stderr
+++ b/src/test/ui/generator/yield-while-ref-reborrowed.stderr
@@ -1,5 +1,5 @@
 error[E0501]: cannot borrow `x` as immutable because previous closure requires unique access
-  --> $DIR/yield-while-ref-reborrowed.rs:35:20
+  --> $DIR/yield-while-ref-reborrowed.rs:36:20
    |
 LL |     let mut b = || {
    |                 -- closure construction occurs here
@@ -8,7 +8,7 @@ LL |         let a = &mut *x;
 ...
 LL |     println!("{}", x); //~ ERROR
    |                    ^ borrow occurs here
-LL |     b.resume();
+LL |     Pin::new(&mut b).resume();
 LL | }
    | - borrow from closure ends here
 
diff --git a/src/test/ui/generic/generic-no-mangle.rs b/src/test/ui/generic/generic-no-mangle.rs
index 15e662a41de22..994aebc7f6e3e 100644
--- a/src/test/ui/generic/generic-no-mangle.rs
+++ b/src/test/ui/generic/generic-no-mangle.rs
@@ -1,10 +1,10 @@
 #![deny(no_mangle_generic_items)]
 
 #[no_mangle]
-pub fn foo<T>() {} //~ ERROR functions generic over types must be mangled
+pub fn foo<T>() {} //~ ERROR functions generic over types or consts must be mangled
 
 #[no_mangle]
-pub extern fn bar<T>() {} //~ ERROR functions generic over types must be mangled
+pub extern fn bar<T>() {} //~ ERROR functions generic over types or consts must be mangled
 
 #[no_mangle]
 pub fn baz(x: &i32) -> &i32 { x }
diff --git a/src/test/ui/generic/generic-no-mangle.stderr b/src/test/ui/generic/generic-no-mangle.stderr
index 639ee19910155..3da39f1dc17cb 100644
--- a/src/test/ui/generic/generic-no-mangle.stderr
+++ b/src/test/ui/generic/generic-no-mangle.stderr
@@ -1,9 +1,9 @@
-error: functions generic over types must be mangled
+error: functions generic over types or consts must be mangled
   --> $DIR/generic-no-mangle.rs:4:1
    |
 LL | #[no_mangle]
    | ------------ help: remove this attribute
-LL | pub fn foo<T>() {} //~ ERROR functions generic over types must be mangled
+LL | pub fn foo<T>() {} //~ ERROR functions generic over types or consts must be mangled
    | ^^^^^^^^^^^^^^^^^^
    |
 note: lint level defined here
@@ -12,12 +12,12 @@ note: lint level defined here
 LL | #![deny(no_mangle_generic_items)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^
 
-error: functions generic over types must be mangled
+error: functions generic over types or consts must be mangled
   --> $DIR/generic-no-mangle.rs:7:1
    |
 LL | #[no_mangle]
    | ------------ help: remove this attribute
-LL | pub extern fn bar<T>() {} //~ ERROR functions generic over types must be mangled
+LL | pub extern fn bar<T>() {} //~ ERROR functions generic over types or consts must be mangled
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_a_b_ret_a_vs_bound_a_ret_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_a_b_ret_a_vs_bound_a_ret_a.stderr
index bdfabdabbebb7..8e2b0b8c60045 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_a_b_ret_a_vs_bound_a_ret_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_a_b_ret_a_vs_bound_a_ret_a.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ one type is more general than the other
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
 ...
 LL | / check! { bound_a_b_ret_a_vs_bound_a_ret_a: (for<'a,'b> fn(&'a u32, &'b u32) -> &'a u32,
 LL | |                                             for<'a>    fn(&'a u32, &'a u32) -> &'a u32) }
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_a_b_vs_bound_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_a_b_vs_bound_a.stderr
index 25b74d855bb48..dbb5018139076 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_a_b_vs_bound_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_a_b_vs_bound_a.stderr
@@ -1,14 +1,16 @@
-error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+error[E0308]: mismatched types
+  --> $DIR/hr-subtype.rs:39:26
    |
-LL | / fn main() {
-LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-LL | | }
-   | |_^
+LL |               gimme::<$t1>(None::<$t2>);
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+...
+LL | / check! { bound_a_b_vs_bound_a: (for<'a,'b> fn(&'a u32, &'b u32),
+LL | |                                 for<'a>    fn(&'a u32, &'a u32)) }
+   | |__________________________________________________________________- in this macro invocation
+   |
+   = note: expected type `std::option::Option<for<'a, 'b> fn(&'a u32, &'b u32)>`
+              found type `std::option::Option<for<'a> fn(&'a u32, &'a u32)>`
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_a.stderr
index 25b74d855bb48..5fcb63e17bf31 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_a.stderr
@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+  --> $DIR/hr-subtype.rs:100:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
+LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_b.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_b.stderr
index 25b74d855bb48..5fcb63e17bf31 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_b.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_bound_b.stderr
@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+  --> $DIR/hr-subtype.rs:100:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
+LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_free_x.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_free_x.stderr
index 74b8c89b6e86f..db9892b48a6f7 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_free_x.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_a_vs_free_x.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ one type is more general than the other
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
 ...
 LL | / check! { bound_a_vs_free_x: (for<'a> fn(&'a u32),
 LL | |                              fn(&'x u32)) }
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_b_vs_bound_co_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_b_vs_bound_co_a.stderr
index 25b74d855bb48..e9fb73411bd39 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_b_vs_bound_co_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_b_vs_bound_co_a.stderr
@@ -1,14 +1,16 @@
-error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+error[E0308]: mismatched types
+  --> $DIR/hr-subtype.rs:39:26
    |
-LL | / fn main() {
-LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-LL | | }
-   | |_^
+LL |               gimme::<$t1>(None::<$t2>);
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+...
+LL | / check! { bound_co_a_b_vs_bound_co_a: (for<'a,'b> fn(Co<'a>, Co<'b>),
+LL | |                                       for<'a>    fn(Co<'a>, Co<'a>)) }
+   | |______________________________________________________________________- in this macro invocation
+   |
+   = note: expected type `std::option::Option<for<'a, 'b> fn(Co<'a>, Co<'b>)>`
+              found type `std::option::Option<for<'a> fn(Co<'a>, Co<'a>)>`
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_co_b_ret_contra_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_co_b_ret_contra_a.stderr
index 25b74d855bb48..d0e80faa68e8b 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_co_b_ret_contra_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_co_b_ret_contra_a.stderr
@@ -1,14 +1,16 @@
-error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+error[E0308]: mismatched types
+  --> $DIR/hr-subtype.rs:39:26
    |
-LL | / fn main() {
-LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-LL | | }
-   | |_^
+LL |               gimme::<$t1>(None::<$t2>);
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+...
+LL | / check! { bound_co_a_co_b_ret_contra_a: (for<'a,'b> fn(Co<'a>, Co<'b>) -> Contra<'a>,
+LL | |                                         for<'a>    fn(Co<'a>, Co<'a>) -> Contra<'a>) }
+   | |______________________________________________________________________________________- in this macro invocation
+   |
+   = note: expected type `std::option::Option<for<'a, 'b> fn(Co<'a>, Co<'b>) -> Contra<'a>>`
+              found type `std::option::Option<for<'a> fn(Co<'a>, Co<'a>) -> Contra<'a>>`
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_vs_bound_co_b.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_vs_bound_co_b.stderr
index 25b74d855bb48..5fcb63e17bf31 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_co_a_vs_bound_co_b.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_co_a_vs_bound_co_b.stderr
@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+  --> $DIR/hr-subtype.rs:100:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
+LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_contra_a_contra_b_ret_co_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_contra_a_contra_b_ret_co_a.stderr
index 25b74d855bb48..3605ecf4f8667 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_contra_a_contra_b_ret_co_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_contra_a_contra_b_ret_co_a.stderr
@@ -1,14 +1,16 @@
-error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+error[E0308]: mismatched types
+  --> $DIR/hr-subtype.rs:39:26
    |
-LL | / fn main() {
-LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
-LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
-LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
-LL | | }
-   | |_^
+LL |               gimme::<$t1>(None::<$t2>);
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
+...
+LL | / check! { bound_contra_a_contra_b_ret_co_a: (for<'a,'b> fn(Contra<'a>, Contra<'b>) -> Co<'a>,
+LL | |                                             for<'a>    fn(Contra<'a>, Contra<'a>) -> Co<'a>) }
+   | |______________________________________________________________________________________________- in this macro invocation
+   |
+   = note: expected type `std::option::Option<for<'a, 'b> fn(Contra<'a>, Contra<'b>) -> Co<'a>>`
+              found type `std::option::Option<for<'a> fn(Contra<'a>, Contra<'a>) -> Co<'a>>`
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_b_vs_bound_inv_a.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_b_vs_bound_inv_a.stderr
index 8168941e2777c..fae6e9b5c89ca 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_b_vs_bound_inv_a.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_b_vs_bound_inv_a.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/hr-subtype.rs:39:26
    |
 LL |               gimme::<$t1>(None::<$t2>);
-   |                            ^^^^^^^^^^^ one type is more general than the other
+   |                            ^^^^^^^^^^^ expected concrete lifetime, found bound lifetime parameter 'a
 ...
 LL | / check! { bound_inv_a_b_vs_bound_inv_a: (for<'a,'b> fn(Inv<'a>, Inv<'b>),
 LL | |                                         for<'a>    fn(Inv<'a>, Inv<'a>)) }
diff --git a/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_vs_bound_inv_b.stderr b/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_vs_bound_inv_b.stderr
index 25b74d855bb48..5fcb63e17bf31 100644
--- a/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_vs_bound_inv_b.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.bound_inv_a_vs_bound_inv_b.stderr
@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+  --> $DIR/hr-subtype.rs:100:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
+LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 
diff --git a/src/test/ui/hr-subtype/hr-subtype.free_x_vs_free_x.stderr b/src/test/ui/hr-subtype/hr-subtype.free_x_vs_free_x.stderr
index 25b74d855bb48..5fcb63e17bf31 100644
--- a/src/test/ui/hr-subtype/hr-subtype.free_x_vs_free_x.stderr
+++ b/src/test/ui/hr-subtype/hr-subtype.free_x_vs_free_x.stderr
@@ -1,12 +1,12 @@
 error: compilation successful
-  --> $DIR/hr-subtype.rs:96:1
+  --> $DIR/hr-subtype.rs:100:1
    |
 LL | / fn main() {
 LL | | //[bound_a_vs_bound_a]~^ ERROR compilation successful
 LL | | //[bound_a_vs_bound_b]~^^ ERROR compilation successful
 LL | | //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
-...  |
-LL | | //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
+LL | | //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
+LL | | //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
 LL | | }
    | |_^
 
diff --git a/src/test/ui/hr-subtype/hr-subtype.rs b/src/test/ui/hr-subtype/hr-subtype.rs
index ad4f39f840528..2f7c1e6fd8c0d 100644
--- a/src/test/ui/hr-subtype/hr-subtype.rs
+++ b/src/test/ui/hr-subtype/hr-subtype.rs
@@ -42,6 +42,10 @@ macro_rules! check {
             //[bound_inv_a_b_vs_bound_inv_a]~^^^ ERROR
             //[bound_a_b_ret_a_vs_bound_a_ret_a]~^^^^ ERROR
             //[free_inv_x_vs_free_inv_y]~^^^^^ ERROR
+            //[bound_a_b_vs_bound_a]~^^^^^^ ERROR mismatched types
+            //[bound_co_a_co_b_ret_contra_a]~^^^^^^^ ERROR
+            //[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^ ERROR
+            //[bound_co_a_b_vs_bound_co_a]~^^^^^^^^^ ERROR
         }
     }
 }
@@ -99,8 +103,4 @@ fn main() {
 //[bound_inv_a_vs_bound_inv_b]~^^^ ERROR compilation successful
 //[bound_co_a_vs_bound_co_b]~^^^^ ERROR compilation successful
 //[free_x_vs_free_x]~^^^^^ ERROR compilation successful
-//[bound_a_b_vs_bound_a]~^^^^^^ ERROR compilation successful
-//[bound_co_a_co_b_ret_contra_a]~^^^^^^^ ERROR compilation successful
-//[bound_co_a_b_vs_bound_co_a]~^^^^^^^^ ERROR compilation successful
-//[bound_contra_a_contra_b_ret_co_a]~^^^^^^^^^ ERROR compilation successful
 }
diff --git a/src/test/ui/hrtb/hrtb-cache-issue-54302.stderr b/src/test/ui/hrtb/hrtb-cache-issue-54302.stderr
index e82fa51524ef1..21d154eb2316c 100644
--- a/src/test/ui/hrtb/hrtb-cache-issue-54302.stderr
+++ b/src/test/ui/hrtb/hrtb-cache-issue-54302.stderr
@@ -4,8 +4,8 @@ error: implementation of `Deserialize` is not general enough
 LL |     assert_deserialize_owned::<&'static str>(); //~ ERROR
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'static str` must implement `Deserialize<'0>` for any lifetime `'0`
-   = note: but `&str` only implements `Deserialize<'1>` for some lifetime `'1`
+   = note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`
+   = note: but `&str` actually implements `Deserialize<'1>`, for some specific lifetime `'1`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/hrtb/hrtb-conflate-regions.stderr b/src/test/ui/hrtb/hrtb-conflate-regions.stderr
index 2ee398e3dd3b2..50e1af8f14231 100644
--- a/src/test/ui/hrtb/hrtb-conflate-regions.stderr
+++ b/src/test/ui/hrtb/hrtb-conflate-regions.stderr
@@ -1,12 +1,20 @@
-error: implementation of `Foo` is not general enough
+error[E0277]: the trait bound `for<'a, 'b> SomeStruct: Foo<(&'a isize, &'b isize)>` is not satisfied
   --> $DIR/hrtb-conflate-regions.rs:28:10
    |
 LL | fn b() { want_foo2::<SomeStruct>(); } //~ ERROR
-   |          ^^^^^^^^^^^^^^^^^^^^^^^
+   |          ^^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'a, 'b> Foo<(&'a isize, &'b isize)>` is not implemented for `SomeStruct`
    |
-   = note: Due to a where-clause on `want_foo2`,
-   = note: `SomeStruct` must implement `Foo<(&'0 isize, &'1 isize)>` for any two lifetimes `'0` and `'1`
-   = note: but `SomeStruct` only implements `Foo<(&'2 isize, &'2 isize)>` for some lifetime `'2`
+   = help: the following implementations were found:
+             <SomeStruct as Foo<(&'a isize, &'a isize)>>
+note: required by `want_foo2`
+  --> $DIR/hrtb-conflate-regions.rs:8:1
+   |
+LL | / fn want_foo2<T>()
+LL | |     where T : for<'a,'b> Foo<(&'a isize, &'b isize)>
+LL | | {
+LL | | }
+   | |_^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-fn.stderr b/src/test/ui/hrtb/hrtb-exists-forall-fn.stderr
index 6301ed45ac277..8e8892552b701 100644
--- a/src/test/ui/hrtb/hrtb-exists-forall-fn.stderr
+++ b/src/test/ui/hrtb/hrtb-exists-forall-fn.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/hrtb-exists-forall-fn.rs:17:34
    |
 LL |     let _: for<'b> fn(&'b u32) = foo(); //~ ERROR mismatched types
-   |                                  ^^^^^ one type is more general than the other
+   |                                  ^^^^^ expected concrete lifetime, found bound lifetime parameter 'b
    |
    = note: expected type `for<'b> fn(&'b u32)`
               found type `fn(&u32)`
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.rs b/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.rs
index 8801760056ecb..4c1d4d28a09b0 100644
--- a/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.rs
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.rs
@@ -1,9 +1,7 @@
-// Test a `exists<'a> { forall<'b> { 'a = 'b } }` pattern -- which should not compile!
+// Test a case where variance and higher-ranked types interact in surprising ways.
 //
 // In particular, we test this pattern in trait solving, where it is not connected
 // to any part of the source code.
-//
-// compile-pass
 
 trait Trait<T> {}
 
@@ -30,6 +28,9 @@ fn main() {
     //     - `?a: ?b` -- solveable if `?b` is also inferred to `'empty`
     // - So the subtyping check succeeds, somewhat surprisingly.
     //   This is because we can use `'empty`.
+    //
+    // NB. *However*, the reinstated leak-check gives an error here.
 
     foo::<()>();
+    //~^ ERROR not satisfied
 }
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.stderr b/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.stderr
new file mode 100644
index 0000000000000..7f2ca037f0f49
--- /dev/null
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-contravariant.stderr
@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `(): Trait<for<'b> fn(&'b u32)>` is not satisfied
+  --> $DIR/hrtb-exists-forall-trait-contravariant.rs:34:5
+   |
+LL |     foo::<()>();
+   |     ^^^^^^^^^ the trait `Trait<for<'b> fn(&'b u32)>` is not implemented for `()`
+   |
+   = help: the following implementations were found:
+             <() as Trait<fn(&'a u32)>>
+note: required by `foo`
+  --> $DIR/hrtb-exists-forall-trait-contravariant.rs:8:1
+   |
+LL | / fn foo<T>()
+LL | | where
+LL | |     T: Trait<for<'b> fn(&'b u32)>,
+LL | | {
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.rs b/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.rs
index da1bb7cd5fd0b..95b57d6c5bb5e 100644
--- a/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.rs
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.rs
@@ -1,9 +1,7 @@
-// Test a `exists<'a> { forall<'b> { 'a = 'b } }` pattern -- which should not compile!
+// Test a case where variance and higher-ranked types interact in surprising ways.
 //
 // In particular, we test this pattern in trait solving, where it is not connected
 // to any part of the source code.
-//
-// compile-pass
 
 trait Trait<T> {}
 
@@ -32,6 +30,9 @@ fn main() {
     //         - `?b: ?a` -- solveable if `?b` is inferred to `'static`
     // - So the subtyping check succeeds, somewhat surprisingly.
     //   This is because we can use `'static`.
+    //
+    // NB. *However*, the reinstated leak-check gives an error here.
 
     foo::<()>();
+    //~^ ERROR not satisfied
 }
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.stderr b/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.stderr
new file mode 100644
index 0000000000000..cd5982e7588a7
--- /dev/null
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-covariant.stderr
@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `(): Trait<for<'b> fn(fn(&'b u32))>` is not satisfied
+  --> $DIR/hrtb-exists-forall-trait-covariant.rs:36:5
+   |
+LL |     foo::<()>();
+   |     ^^^^^^^^^ the trait `Trait<for<'b> fn(fn(&'b u32))>` is not implemented for `()`
+   |
+   = help: the following implementations were found:
+             <() as Trait<fn(fn(&'a u32))>>
+note: required by `foo`
+  --> $DIR/hrtb-exists-forall-trait-covariant.rs:8:1
+   |
+LL | / fn foo<T>()
+LL | | where
+LL | |     T: Trait<for<'b> fn(fn(&'b u32))>,
+LL | | {
+LL | | }
+   | |_^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.rs b/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.rs
index da3f8ad1b8957..827a68beee8bd 100644
--- a/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.rs
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.rs
@@ -25,5 +25,5 @@ fn main() {
     //     yielding `fn(&!b u32)`, in a fresh universe U1
     //   - So we get `?a = !b` but the universe U0 assigned to `?a` cannot name `!b`.
 
-    foo::<()>(); //~ ERROR not general enough
+    foo::<()>(); //~ ERROR not satisfied
 }
diff --git a/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.stderr b/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.stderr
index 6a61181e2407c..f56b81759fede 100644
--- a/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.stderr
+++ b/src/test/ui/hrtb/hrtb-exists-forall-trait-invariant.stderr
@@ -1,12 +1,21 @@
-error: implementation of `Trait` is not general enough
+error[E0277]: the trait bound `(): Trait<for<'b> fn(std::cell::Cell<&'b u32>)>` is not satisfied
   --> $DIR/hrtb-exists-forall-trait-invariant.rs:28:5
    |
-LL |     foo::<()>(); //~ ERROR not general enough
-   |     ^^^^^^^^^
+LL |     foo::<()>(); //~ ERROR not satisfied
+   |     ^^^^^^^^^ the trait `Trait<for<'b> fn(std::cell::Cell<&'b u32>)>` is not implemented for `()`
    |
-   = note: Due to a where-clause on `foo`,
-   = note: `()` must implement `Trait<for<'b> fn(std::cell::Cell<&'b u32>)>`
-   = note: but `()` only implements `Trait<fn(std::cell::Cell<&'0 u32>)>` for some lifetime `'0`
+   = help: the following implementations were found:
+             <() as Trait<fn(std::cell::Cell<&'a u32>)>>
+note: required by `foo`
+  --> $DIR/hrtb-exists-forall-trait-invariant.rs:10:1
+   |
+LL | / fn foo<T>()
+LL | | where
+LL | |     T: Trait<for<'b> fn(Cell<&'b u32>)>,
+LL | | {
+LL | | }
+   | |_^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits-transitive.stderr b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits-transitive.stderr
index 0d7b5cbf82348..77c1789852e52 100644
--- a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits-transitive.stderr
+++ b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits-transitive.stderr
@@ -1,12 +1,19 @@
-error[E0308]: mismatched types
+error[E0277]: the trait bound `for<'ccx> B: Bar<'ccx>` is not satisfied
   --> $DIR/hrtb-higher-ranker-supertraits-transitive.rs:47:5
    |
 LL |     want_bar_for_any_ccx(b); //~ ERROR
-   |     ^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+   |     ^^^^^^^^^^^^^^^^^^^^ the trait `for<'ccx> Bar<'ccx>` is not implemented for `B`
    |
-   = note: expected type `for<'ccx> Bar<'ccx>`
-              found type `Bar<'static>`
+   = help: consider adding a `where for<'ccx> B: Bar<'ccx>` bound
+note: required by `want_bar_for_any_ccx`
+  --> $DIR/hrtb-higher-ranker-supertraits-transitive.rs:31:1
+   |
+LL | / fn want_bar_for_any_ccx<B>(b: &B)
+LL | |     where B : for<'ccx> Bar<'ccx>
+LL | | {
+LL | | }
+   | |_^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.rs b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.rs
index 3d2d403462d8b..48ebe5017aa62 100644
--- a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.rs
+++ b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.rs
@@ -15,7 +15,7 @@ fn want_foo_for_some_tcx<'x,F>(f: &'x F)
     where F : Foo<'x>
 {
     want_foo_for_some_tcx(f);
-    want_foo_for_any_tcx(f); //~ ERROR E0308
+    want_foo_for_any_tcx(f); //~ ERROR not satisfied
 }
 
 fn want_foo_for_any_tcx<F>(f: &F)
@@ -32,7 +32,7 @@ fn want_bar_for_some_ccx<'x,B>(b: &B)
     want_foo_for_any_tcx(b);
 
     want_bar_for_some_ccx(b);
-    want_bar_for_any_ccx(b); //~ ERROR E0308
+    want_bar_for_any_ccx(b); //~ ERROR not satisfied
 }
 
 fn want_bar_for_any_ccx<B>(b: &B)
diff --git a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.stderr b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.stderr
index 31dbeec2a551b..5914cb3eaa494 100644
--- a/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.stderr
+++ b/src/test/ui/hrtb/hrtb-higher-ranker-supertraits.stderr
@@ -1,21 +1,40 @@
-error[E0308]: mismatched types
+error[E0277]: the trait bound `for<'tcx> F: Foo<'tcx>` is not satisfied
   --> $DIR/hrtb-higher-ranker-supertraits.rs:18:5
    |
-LL |     want_foo_for_any_tcx(f); //~ ERROR E0308
-   |     ^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+LL |     want_foo_for_any_tcx(f); //~ ERROR not satisfied
+   |     ^^^^^^^^^^^^^^^^^^^^ the trait `for<'tcx> Foo<'tcx>` is not implemented for `F`
    |
-   = note: expected type `for<'tcx> Foo<'tcx>`
-              found type `Foo<'x>`
+   = help: consider adding a `where for<'tcx> F: Foo<'tcx>` bound
+note: required by `want_foo_for_any_tcx`
+  --> $DIR/hrtb-higher-ranker-supertraits.rs:21:1
+   |
+LL | / fn want_foo_for_any_tcx<F>(f: &F)
+LL | |     where F : for<'tcx> Foo<'tcx>
+LL | | {
+LL | |     want_foo_for_some_tcx(f);
+LL | |     want_foo_for_any_tcx(f);
+LL | | }
+   | |_^
 
-error[E0308]: mismatched types
+error[E0277]: the trait bound `for<'ccx> B: Bar<'ccx>` is not satisfied
   --> $DIR/hrtb-higher-ranker-supertraits.rs:35:5
    |
-LL |     want_bar_for_any_ccx(b); //~ ERROR E0308
-   |     ^^^^^^^^^^^^^^^^^^^^ one type is more general than the other
+LL |     want_bar_for_any_ccx(b); //~ ERROR not satisfied
+   |     ^^^^^^^^^^^^^^^^^^^^ the trait `for<'ccx> Bar<'ccx>` is not implemented for `B`
+   |
+   = help: consider adding a `where for<'ccx> B: Bar<'ccx>` bound
+note: required by `want_bar_for_any_ccx`
+  --> $DIR/hrtb-higher-ranker-supertraits.rs:38:1
    |
-   = note: expected type `for<'ccx> Bar<'ccx>`
-              found type `Bar<'x>`
+LL | / fn want_bar_for_any_ccx<B>(b: &B)
+LL | |     where B : for<'ccx> Bar<'ccx>
+LL | | {
+LL | |     want_foo_for_some_tcx(b);
+...  |
+LL | |     want_bar_for_any_ccx(b);
+LL | | }
+   | |_^
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-just-for-static.stderr b/src/test/ui/hrtb/hrtb-just-for-static.stderr
index 094c449802415..fe2bc1f222504 100644
--- a/src/test/ui/hrtb/hrtb-just-for-static.stderr
+++ b/src/test/ui/hrtb/hrtb-just-for-static.stderr
@@ -1,22 +1,37 @@
-error: implementation of `Foo` is not general enough
+error[E0277]: the trait bound `for<'a> StaticInt: Foo<&'a isize>` is not satisfied
   --> $DIR/hrtb-just-for-static.rs:24:5
    |
 LL |     want_hrtb::<StaticInt>() //~ ERROR
-   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^^^ the trait `for<'a> Foo<&'a isize>` is not implemented for `StaticInt`
    |
-   = note: Due to a where-clause on `want_hrtb`,
-   = note: `StaticInt` must implement `Foo<&'0 isize>` for any lifetime `'0`
-   = note: but `StaticInt` only implements `Foo<&'1 isize>` for some lifetime `'1`
+   = help: the following implementations were found:
+             <StaticInt as Foo<&'static isize>>
+note: required by `want_hrtb`
+  --> $DIR/hrtb-just-for-static.rs:8:1
+   |
+LL | / fn want_hrtb<T>()
+LL | |     where T : for<'a> Foo<&'a isize>
+LL | | {
+LL | | }
+   | |_^
 
-error: implementation of `Foo` is not general enough
+error[E0277]: the trait bound `for<'a> &'a u32: Foo<&'a isize>` is not satisfied
   --> $DIR/hrtb-just-for-static.rs:30:5
    |
 LL |     want_hrtb::<&'a u32>() //~ ERROR
-   |     ^^^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^^^^^ the trait `for<'a> Foo<&'a isize>` is not implemented for `&'a u32`
+   |
+   = help: the following implementations were found:
+             <&'a u32 as Foo<&'a isize>>
+note: required by `want_hrtb`
+  --> $DIR/hrtb-just-for-static.rs:8:1
    |
-   = note: Due to a where-clause on `want_hrtb`,
-   = note: `&'a u32` must implement `Foo<&'0 isize>` for any lifetime `'0`
-   = note: but `&'1 u32` only implements `Foo<&'1 isize>` for the lifetime `'1`
+LL | / fn want_hrtb<T>()
+LL | |     where T : for<'a> Foo<&'a isize>
+LL | | {
+LL | | }
+   | |_^
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/hrtb-perfect-forwarding.rs b/src/test/ui/hrtb/hrtb-perfect-forwarding.rs
index 7bd89960e42e5..63db695f7e67c 100644
--- a/src/test/ui/hrtb/hrtb-perfect-forwarding.rs
+++ b/src/test/ui/hrtb/hrtb-perfect-forwarding.rs
@@ -43,7 +43,7 @@ fn foo_hrtb_bar_not<'b,T>(mut t: T)
     // be implemented. Thus to satisfy `&mut T : for<'a> Foo<&'a
     // isize>`, we require `T : for<'a> Bar<&'a isize>`, but the where
     // clause only specifies `T : Bar<&'b isize>`.
-    foo_hrtb_bar_not(&mut t); //~ ERROR E0308
+    foo_hrtb_bar_not(&mut t); //~ ERROR mismatched types
 }
 
 fn foo_hrtb_bar_hrtb<T>(mut t: T)
diff --git a/src/test/ui/hrtb/hrtb-perfect-forwarding.stderr b/src/test/ui/hrtb/hrtb-perfect-forwarding.stderr
index ec3bf8a1a1be3..ea08af0164061 100644
--- a/src/test/ui/hrtb/hrtb-perfect-forwarding.stderr
+++ b/src/test/ui/hrtb/hrtb-perfect-forwarding.stderr
@@ -1,11 +1,11 @@
 error[E0308]: mismatched types
   --> $DIR/hrtb-perfect-forwarding.rs:46:5
    |
-LL |     foo_hrtb_bar_not(&mut t); //~ ERROR E0308
+LL |     foo_hrtb_bar_not(&mut t); //~ ERROR mismatched types
    |     ^^^^^^^^^^^^^^^^ one type is more general than the other
    |
-   = note: expected type `Foo<&'a isize>`
-              found type `Foo<&isize>`
+   = note: expected type `Bar<&'a isize>`
+              found type `Bar<&'b isize>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/hrtb/issue-46989.rs b/src/test/ui/hrtb/issue-46989.rs
new file mode 100644
index 0000000000000..2c85905545807
--- /dev/null
+++ b/src/test/ui/hrtb/issue-46989.rs
@@ -0,0 +1,42 @@
+// Regression test for #46989:
+//
+// In the move to universes, this test started passing.
+// It is not necessarily WRONG to do so, but it was a bit
+// surprising. The reason that it passed is that when we were
+// asked to prove that
+//
+//     for<'a> fn(&'a i32): Foo
+//
+// we were able to use the impl below to prove
+//
+//     fn(&'empty i32): Foo
+//
+// and then we were able to prove that
+//
+//     fn(&'empty i32) = for<'a> fn(&'a i32)
+//
+// This last fact is somewhat surprising, but essentially "falls out"
+// from handling variance correctly. In particular, consider the subtyping
+// relations. First:
+//
+//     fn(&'empty i32) <: for<'a> fn(&'a i32)
+//
+// This holds because -- intuitively -- a fn that takes a reference but doesn't use
+// it can be given a reference with any lifetime. Similarly, the opposite direction:
+//
+//     for<'a> fn(&'a i32) <: fn(&'empty i32)
+//
+// holds because 'a can be instantiated to 'empty.
+
+trait Foo {
+
+}
+
+impl<A> Foo for fn(A) { }
+
+fn assert_foo<T: Foo>() {}
+
+fn main() {
+    assert_foo::<fn(&i32)>();
+    //~^ ERROR the trait bound `for<'r> fn(&'r i32): Foo` is not satisfied
+}
diff --git a/src/test/ui/hrtb/issue-46989.stderr b/src/test/ui/hrtb/issue-46989.stderr
new file mode 100644
index 0000000000000..b308291d5c0eb
--- /dev/null
+++ b/src/test/ui/hrtb/issue-46989.stderr
@@ -0,0 +1,17 @@
+error[E0277]: the trait bound `for<'r> fn(&'r i32): Foo` is not satisfied
+  --> $DIR/issue-46989.rs:40:5
+   |
+LL |     assert_foo::<fn(&i32)>();
+   |     ^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `for<'r> fn(&'r i32)`
+   |
+   = help: the following implementations were found:
+             <fn(A) as Foo>
+note: required by `assert_foo`
+  --> $DIR/issue-46989.rs:37:1
+   |
+LL | fn assert_foo<T: Foo>() {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/hrtb/issue-57639.rs b/src/test/ui/hrtb/issue-57639.rs
new file mode 100644
index 0000000000000..4bcaef3616bd5
--- /dev/null
+++ b/src/test/ui/hrtb/issue-57639.rs
@@ -0,0 +1,29 @@
+// Regression test for #57639:
+//
+// In the move to universes, this test stopped working. The problem
+// was that when the trait solver was asked to prove `for<'a> T::Item:
+// Foo<'a>` as part of WF checking, it wound up "eagerly committing"
+// to the where clause, which says that `T::Item: Foo<'a>`, but it
+// should instead have been using the bound found in the trait
+// declaration. Pre-universe, this used to work out ok because we got
+// "eager errors" due to the leak check.
+//
+// See [this comment on GitHub][c] for more details.
+//
+// run-pass
+//
+// [c]: https://github.com/rust-lang/rust/issues/57639#issuecomment-455685861
+
+trait Foo<'a> {}
+
+trait Bar {
+    type Item: for<'a> Foo<'a>;
+}
+
+fn foo<'a, T>(_: T)
+where
+    T: Bar,
+    T::Item: Foo<'a>,
+{}
+
+fn main() { }
diff --git a/src/test/ui/hrtb/issue-58451.rs b/src/test/ui/hrtb/issue-58451.rs
new file mode 100644
index 0000000000000..229e505767879
--- /dev/null
+++ b/src/test/ui/hrtb/issue-58451.rs
@@ -0,0 +1,13 @@
+// Regression test for #58451:
+//
+// Error reporting here encountered an ICE in the shift to universes.
+
+fn f<I>(i: I)
+where
+    I: IntoIterator,
+    I::Item: for<'a> Into<&'a ()>,
+{}
+
+fn main() {
+    f(&[f()]); //~ ERROR this function takes 1 parameter
+}
diff --git a/src/test/ui/hrtb/issue-58451.stderr b/src/test/ui/hrtb/issue-58451.stderr
new file mode 100644
index 0000000000000..79c24855dc96c
--- /dev/null
+++ b/src/test/ui/hrtb/issue-58451.stderr
@@ -0,0 +1,16 @@
+error[E0061]: this function takes 1 parameter but 0 parameters were supplied
+  --> $DIR/issue-58451.rs:12:9
+   |
+LL | / fn f<I>(i: I)
+LL | | where
+LL | |     I: IntoIterator,
+LL | |     I::Item: for<'a> Into<&'a ()>,
+LL | | {}
+   | |__- defined here
+...
+LL |       f(&[f()]); //~ ERROR this function takes 1 parameter
+   |           ^^^ expected 1 parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0061`.
diff --git a/src/test/ui/huge-enum.rs b/src/test/ui/huge-enum.rs
index 18ef45794af19..71c8fd55b23f3 100644
--- a/src/test/ui/huge-enum.rs
+++ b/src/test/ui/huge-enum.rs
@@ -1,7 +1,5 @@
-// error-pattern: Option
-// normalize-stderr-test "<\[u32; \d+\]>" -> "<[u32; N]>"
-
-// FIXME: work properly with higher limits
+// normalize-stderr-test "std::option::Option<\[u32; \d+\]>" -> "TYPE"
+// normalize-stderr-test "\[u32; \d+\]" -> "TYPE"
 
 #[cfg(target_pointer_width = "32")]
 fn main() {
diff --git a/src/test/ui/huge-enum.stderr b/src/test/ui/huge-enum.stderr
index b7cf25504614a..67cae3d52ed2d 100644
--- a/src/test/ui/huge-enum.stderr
+++ b/src/test/ui/huge-enum.stderr
@@ -1,4 +1,4 @@
-error: the type `std::option::Option<[u32; N]>` is too big for the current architecture
+error: the type `TYPE` is too big for the current architecture
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/if/if-let-arm-types.rs b/src/test/ui/if/if-let-arm-types.rs
index 749c089ae9752..819f5dd1cfc35 100644
--- a/src/test/ui/if/if-let-arm-types.rs
+++ b/src/test/ui/if/if-let-arm-types.rs
@@ -1,10 +1,11 @@
 fn main() {
-    if let Some(b) = None { //~ ERROR: `if let` arms have incompatible types
-        //~^ expected (), found integer
-        //~| expected type `()`
-        //~| found type `{integer}`
+    if let Some(b) = None {
+        //~^ NOTE if let` arms have incompatible types
         ()
     } else {
         1
     };
+    //~^^ ERROR: `if let` arms have incompatible types
+    //~| NOTE expected (), found integer
+    //~| NOTE expected type `()`
 }
diff --git a/src/test/ui/if/if-let-arm-types.stderr b/src/test/ui/if/if-let-arm-types.stderr
index fcf9e4695f675..6401a62c06ba2 100644
--- a/src/test/ui/if/if-let-arm-types.stderr
+++ b/src/test/ui/if/if-let-arm-types.stderr
@@ -1,25 +1,17 @@
 error[E0308]: `if let` arms have incompatible types
-  --> $DIR/if-let-arm-types.rs:2:5
+  --> $DIR/if-let-arm-types.rs:6:9
    |
-LL | /     if let Some(b) = None { //~ ERROR: `if let` arms have incompatible types
-LL | |         //~^ expected (), found integer
-LL | |         //~| expected type `()`
-LL | |         //~| found type `{integer}`
-...  |
+LL | /     if let Some(b) = None {
+LL | |         //~^ NOTE if let` arms have incompatible types
+LL | |         ()
+LL | |     } else {
 LL | |         1
+   | |         ^ expected (), found integer
 LL | |     };
-   | |_____^ expected (), found integer
+   | |_____- `if let` arms have incompatible types
    |
    = note: expected type `()`
               found type `{integer}`
-note: `if let` arm with an incompatible type
-  --> $DIR/if-let-arm-types.rs:7:12
-   |
-LL |       } else {
-   |  ____________^
-LL | |         1
-LL | |     };
-   | |_____^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/auto-trait-leak.stderr b/src/test/ui/impl-trait/auto-trait-leak.stderr
index 4acc400f8e799..b936fed85f48e 100644
--- a/src/test/ui/impl-trait/auto-trait-leak.stderr
+++ b/src/test/ui/impl-trait/auto-trait-leak.stderr
@@ -9,7 +9,7 @@ note: ...which requires processing `cycle1`...
    |
 LL | fn cycle1() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
+   = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
 note: ...which requires processing `cycle2::{{impl-Trait}}`...
   --> $DIR/auto-trait-leak.rs:23:16
    |
@@ -20,7 +20,7 @@ note: ...which requires processing `cycle2`...
    |
 LL | fn cycle2() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
+   = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
    = note: ...which again requires processing `cycle1::{{impl-Trait}}`, completing the cycle
 note: cycle used when checking item types in top-level module
   --> $DIR/auto-trait-leak.rs:3:1
@@ -45,7 +45,7 @@ note: ...which requires processing `cycle1`...
    |
 LL | fn cycle1() -> impl Clone {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
+   = note: ...which requires evaluating trait selection obligation `impl std::clone::Clone: std::marker::Send`...
 note: ...which requires processing `cycle2::{{impl-Trait}}`...
   --> $DIR/auto-trait-leak.rs:23:16
    |
diff --git a/src/test/ui/impl-trait/bindings.rs b/src/test/ui/impl-trait/bindings.rs
index 899303646d671..91d092634a901 100644
--- a/src/test/ui/impl-trait/bindings.rs
+++ b/src/test/ui/impl-trait/bindings.rs
@@ -2,27 +2,27 @@
 
 fn a<T: Clone>(x: T) {
     const foo: impl Clone = x;
-//~^ ERROR can't capture dynamic environment in a fn item
+    //~^ ERROR attempt to use a non-constant value in a constant
 }
 
 fn b<T: Clone>(x: T) {
     let _ = move || {
         const foo: impl Clone = x;
-//~^ ERROR can't capture dynamic environment in a fn item
+        //~^ ERROR attempt to use a non-constant value in a constant
     };
 }
 
 trait Foo<T: Clone> {
     fn a(x: T) {
         const foo: impl Clone = x;
-//~^ ERROR can't capture dynamic environment in a fn item
+        //~^ ERROR attempt to use a non-constant value in a constant
     }
 }
 
 impl<T: Clone> Foo<T> for i32 {
     fn a(x: T) {
         const foo: impl Clone = x;
-//~^ ERROR can't capture dynamic environment in a fn item
+        //~^ ERROR attempt to use a non-constant value in a constant
     }
 }
 
diff --git a/src/test/ui/impl-trait/bindings.stderr b/src/test/ui/impl-trait/bindings.stderr
index 2a9be7a270a73..a5bf583afeaf6 100644
--- a/src/test/ui/impl-trait/bindings.stderr
+++ b/src/test/ui/impl-trait/bindings.stderr
@@ -1,35 +1,27 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/bindings.rs:4:29
    |
 LL |     const foo: impl Clone = x;
-   |                             ^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                             ^ non-constant value
 
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/bindings.rs:10:33
    |
 LL |         const foo: impl Clone = x;
-   |                                 ^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                                 ^ non-constant value
 
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/bindings.rs:17:33
    |
 LL |         const foo: impl Clone = x;
-   |                                 ^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                                 ^ non-constant value
 
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/bindings.rs:24:33
    |
 LL |         const foo: impl Clone = x;
-   |                                 ^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                                 ^ non-constant value
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0434`.
+For more information about this error, try `rustc --explain E0435`.
diff --git a/src/test/ui/impl-trait/equality.stderr b/src/test/ui/impl-trait/equality.stderr
index 57bd70de7c68f..6cd9d07748c27 100644
--- a/src/test/ui/impl-trait/equality.stderr
+++ b/src/test/ui/impl-trait/equality.stderr
@@ -1,8 +1,11 @@
 error[E0308]: mismatched types
   --> $DIR/equality.rs:15:5
    |
+LL | fn two(x: bool) -> impl Foo {
+   |                    -------- expected because this return type...
+LL |     if x {
 LL |         return 1_i32;
-   |                ----- expected because of this statement
+   |                ----- ...is found to be `i32` here
 LL |     }
 LL |     0_u32
    |     ^^^^^ expected i32, found u32
diff --git a/src/test/ui/imports/duplicate.stderr b/src/test/ui/imports/duplicate.stderr
index acd66826fdfb7..29660d908e485 100644
--- a/src/test/ui/imports/duplicate.stderr
+++ b/src/test/ui/imports/duplicate.stderr
@@ -4,13 +4,12 @@ error[E0252]: the name `foo` is defined multiple times
 LL |     use a::foo;
    |         ------ previous import of the value `foo` here
 LL |     use a::foo; //~ ERROR the name `foo` is defined multiple times
-   |         ^^^^^^ `foo` reimported here
+   |     ----^^^^^^-
+   |     |   |
+   |     |   `foo` reimported here
+   |     help: remove unnecessary import
    |
    = note: `foo` must be defined only once in the value namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL |     use a::foo as other_foo; //~ ERROR the name `foo` is defined multiple times
-   |         ^^^^^^^^^^^^^^^^^^^
 
 error[E0659]: `foo` is ambiguous (glob import vs glob import in the same module)
   --> $DIR/duplicate.rs:46:15
diff --git a/src/test/ui/imports/extern-crate-self-fail.rs b/src/test/ui/imports/extern-crate-self/extern-crate-self-fail.rs
similarity index 85%
rename from src/test/ui/imports/extern-crate-self-fail.rs
rename to src/test/ui/imports/extern-crate-self/extern-crate-self-fail.rs
index eab7b7032aa07..defa0e294bd74 100644
--- a/src/test/ui/imports/extern-crate-self-fail.rs
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-fail.rs
@@ -1,5 +1,3 @@
-#![feature(extern_crate_self)]
-
 extern crate self; //~ ERROR `extern crate self;` requires renaming
 
 #[macro_use] //~ ERROR `macro_use` is not supported on `extern crate self`
diff --git a/src/test/ui/imports/extern-crate-self-fail.stderr b/src/test/ui/imports/extern-crate-self/extern-crate-self-fail.stderr
similarity index 91%
rename from src/test/ui/imports/extern-crate-self-fail.stderr
rename to src/test/ui/imports/extern-crate-self/extern-crate-self-fail.stderr
index 0ca0d89eaf08e..b47d10343f689 100644
--- a/src/test/ui/imports/extern-crate-self-fail.stderr
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-fail.stderr
@@ -1,11 +1,11 @@
 error: `extern crate self;` requires renaming
-  --> $DIR/extern-crate-self-fail.rs:3:1
+  --> $DIR/extern-crate-self-fail.rs:1:1
    |
 LL | extern crate self; //~ ERROR `extern crate self;` requires renaming
    | ^^^^^^^^^^^^^^^^^^ help: try: `extern crate self as name;`
 
 error: `macro_use` is not supported on `extern crate self`
-  --> $DIR/extern-crate-self-fail.rs:5:1
+  --> $DIR/extern-crate-self-fail.rs:3:1
    |
 LL | #[macro_use] //~ ERROR `macro_use` is not supported on `extern crate self`
    | ^^^^^^^^^^^^
diff --git a/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-alias.rs b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-alias.rs
new file mode 100644
index 0000000000000..79683522888cb
--- /dev/null
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-alias.rs
@@ -0,0 +1,16 @@
+// run-pass
+
+// Test that a macro can correctly expand the alias
+// in an `extern crate self as ALIAS` item.
+
+fn the_answer() -> usize { 42 }
+
+macro_rules! alias_self {
+    ($alias:ident) => { extern crate self as $alias; }
+}
+
+alias_self!(the_alias);
+
+fn main() {
+    assert_eq!(the_alias::the_answer(), 42);
+}
diff --git a/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-item.rs b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-item.rs
new file mode 100644
index 0000000000000..9c9397999ff67
--- /dev/null
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-item.rs
@@ -0,0 +1,12 @@
+// compile-pass
+
+// Test that `extern crate self;` is accepted
+// syntactically as an item for use in a macro.
+
+macro_rules! accept_item { ($x:item) => {} }
+
+accept_item! {
+    extern crate self;
+}
+
+fn main() {}
diff --git a/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-self.rs b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-self.rs
new file mode 100644
index 0000000000000..009a92e877645
--- /dev/null
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-macro-self.rs
@@ -0,0 +1,16 @@
+// run-pass
+
+// Test that a macro can correctly expand `self` in
+// an `extern crate self as ALIAS` item.
+
+fn the_answer() -> usize { 42 }
+
+macro_rules! extern_something {
+    ($alias:ident) => { extern crate $alias as the_alias; }
+}
+
+extern_something!(self);
+
+fn main() {
+    assert_eq!(the_alias::the_answer(), 42);
+}
diff --git a/src/test/ui/imports/extern-crate-self-pass.rs b/src/test/ui/imports/extern-crate-self/extern-crate-self-pass.rs
similarity index 79%
rename from src/test/ui/imports/extern-crate-self-pass.rs
rename to src/test/ui/imports/extern-crate-self/extern-crate-self-pass.rs
index bf255bb6b8194..6f6343a614886 100644
--- a/src/test/ui/imports/extern-crate-self-pass.rs
+++ b/src/test/ui/imports/extern-crate-self/extern-crate-self-pass.rs
@@ -1,7 +1,5 @@
 // compile-pass
 
-#![feature(extern_crate_self)]
-
 extern crate self as foo;
 
 struct S;
diff --git a/src/test/ui/imports/issue-57539.rs b/src/test/ui/imports/issue-57539.rs
new file mode 100644
index 0000000000000..90b74eb464779
--- /dev/null
+++ b/src/test/ui/imports/issue-57539.rs
@@ -0,0 +1,8 @@
+// edition:2018
+
+mod core {
+    use core; //~ ERROR `core` is ambiguous
+    use crate::*;
+}
+
+fn main() {}
diff --git a/src/test/ui/imports/issue-57539.stderr b/src/test/ui/imports/issue-57539.stderr
new file mode 100644
index 0000000000000..3f745fd8204bf
--- /dev/null
+++ b/src/test/ui/imports/issue-57539.stderr
@@ -0,0 +1,18 @@
+error[E0659]: `core` is ambiguous (name vs any other name during import resolution)
+  --> $DIR/issue-57539.rs:4:9
+   |
+LL |     use core; //~ ERROR `core` is ambiguous
+   |         ^^^^ ambiguous name
+   |
+   = note: `core` could refer to a built-in extern crate
+   = help: use `::core` to refer to this extern crate unambiguously
+note: `core` could also refer to the module imported here
+  --> $DIR/issue-57539.rs:5:9
+   |
+LL |     use crate::*;
+   |         ^^^^^^^^
+   = help: use `self::core` to refer to this module unambiguously
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0659`.
diff --git a/src/test/ui/index-help.stderr b/src/test/ui/index-help.stderr
index c8b23d812e1b5..4c585a958c14b 100644
--- a/src/test/ui/index-help.stderr
+++ b/src/test/ui/index-help.stderr
@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[{integer}]>` is not satisfied
+error[E0277]: the type `[{integer}]` cannot be indexed by `i32`
   --> $DIR/index-help.rs:3:5
    |
 LL |     x[0i32]; //~ ERROR E0277
diff --git a/src/test/ui/indexing-requires-a-uint.rs b/src/test/ui/indexing-requires-a-uint.rs
index 2db3c58ec519f..dbe9b44a13890 100644
--- a/src/test/ui/indexing-requires-a-uint.rs
+++ b/src/test/ui/indexing-requires-a-uint.rs
@@ -3,7 +3,7 @@
 
 fn main() {
     fn bar<T>(_: T) {}
-    [0][0u8]; //~ ERROR: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+    [0][0u8]; //~ ERROR: the type `[{integer}]` cannot be indexed by `u8`
 
     [0][0]; // should infer to be a usize
 
diff --git a/src/test/ui/indexing-requires-a-uint.stderr b/src/test/ui/indexing-requires-a-uint.stderr
index 767f1af2c46e9..363c3d0d45853 100644
--- a/src/test/ui/indexing-requires-a-uint.stderr
+++ b/src/test/ui/indexing-requires-a-uint.stderr
@@ -1,7 +1,7 @@
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+error[E0277]: the type `[{integer}]` cannot be indexed by `u8`
   --> $DIR/indexing-requires-a-uint.rs:6:5
    |
-LL |     [0][0u8]; //~ ERROR: the trait bound `u8: std::slice::SliceIndex<[{integer}]>` is not satisfied
+LL |     [0][0u8]; //~ ERROR: the type `[{integer}]` cannot be indexed by `u8`
    |     ^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[{integer}]>` is not implemented for `u8`
diff --git a/src/test/ui/inner-static-type-parameter.rs b/src/test/ui/inner-static-type-parameter.rs
index 60b4c5b8131b3..c08ccd29d8011 100644
--- a/src/test/ui/inner-static-type-parameter.rs
+++ b/src/test/ui/inner-static-type-parameter.rs
@@ -4,7 +4,7 @@ enum Bar<T> { What } //~ ERROR parameter `T` is never used
 
 fn foo<T>() {
     static a: Bar<T> = Bar::What;
-//~^ ERROR can't use type parameters from outer function
+//~^ ERROR can't use generic parameters from outer function
 }
 
 fn main() {
diff --git a/src/test/ui/inner-static-type-parameter.stderr b/src/test/ui/inner-static-type-parameter.stderr
index 2f2856edb0ca9..87fb364954d96 100644
--- a/src/test/ui/inner-static-type-parameter.stderr
+++ b/src/test/ui/inner-static-type-parameter.stderr
@@ -1,12 +1,12 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/inner-static-type-parameter.rs:6:19
    |
 LL | fn foo<T>() {
    |    --- - type variable from outer function
    |    |
-   |    try adding a local type parameter in this method instead
+   |    try adding a local generic parameter in this method instead
 LL |     static a: Bar<T> = Bar::What;
-   |                   ^ use of type variable from outer function
+   |                   ^ use of generic parameter from outer function
 
 error[E0392]: parameter `T` is never used
   --> $DIR/inner-static-type-parameter.rs:3:10
diff --git a/src/test/ui/integral-indexing.rs b/src/test/ui/integral-indexing.rs
index 7bdbc45879b9d..f076dfcb0a42c 100644
--- a/src/test/ui/integral-indexing.rs
+++ b/src/test/ui/integral-indexing.rs
@@ -3,14 +3,14 @@ pub fn main() {
     let s: String = "abcdef".to_string();
     v[3_usize];
     v[3];
-    v[3u8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3i8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3u32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
-    v[3i32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+    v[3u8];  //~ERROR : the type `[isize]` cannot be indexed by `u8`
+    v[3i8];  //~ERROR : the type `[isize]` cannot be indexed by `i8`
+    v[3u32]; //~ERROR : the type `[isize]` cannot be indexed by `u32`
+    v[3i32]; //~ERROR : the type `[isize]` cannot be indexed by `i32`
     s.as_bytes()[3_usize];
     s.as_bytes()[3];
-    s.as_bytes()[3u8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3i8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3u32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
-    s.as_bytes()[3i32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+    s.as_bytes()[3u8];  //~ERROR : the type `[u8]` cannot be indexed by `u8`
+    s.as_bytes()[3i8];  //~ERROR : the type `[u8]` cannot be indexed by `i8`
+    s.as_bytes()[3u32]; //~ERROR : the type `[u8]` cannot be indexed by `u32`
+    s.as_bytes()[3i32]; //~ERROR : the type `[u8]` cannot be indexed by `i32`
 }
diff --git a/src/test/ui/integral-indexing.stderr b/src/test/ui/integral-indexing.stderr
index 7f2dddcf7b8c3..efbad86c4d31b 100644
--- a/src/test/ui/integral-indexing.stderr
+++ b/src/test/ui/integral-indexing.stderr
@@ -1,70 +1,70 @@
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `u8`
   --> $DIR/integral-indexing.rs:6:5
    |
-LL |     v[3u8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3u8];  //~ERROR : the type `[isize]` cannot be indexed by `u8`
    |     ^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `u8`
    = note: required because of the requirements on the impl of `std::ops::Index<u8>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `i8: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `i8`
   --> $DIR/integral-indexing.rs:7:5
    |
-LL |     v[3i8];  //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3i8];  //~ERROR : the type `[isize]` cannot be indexed by `i8`
    |     ^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `i8`
    = note: required because of the requirements on the impl of `std::ops::Index<i8>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `u32: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `u32`
   --> $DIR/integral-indexing.rs:8:5
    |
-LL |     v[3u32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3u32]; //~ERROR : the type `[isize]` cannot be indexed by `u32`
    |     ^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `u32`
    = note: required because of the requirements on the impl of `std::ops::Index<u32>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[isize]>` is not satisfied
+error[E0277]: the type `[isize]` cannot be indexed by `i32`
   --> $DIR/integral-indexing.rs:9:5
    |
-LL |     v[3i32]; //~ERROR : std::slice::SliceIndex<[isize]>` is not satisfied
+LL |     v[3i32]; //~ERROR : the type `[isize]` cannot be indexed by `i32`
    |     ^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[isize]>` is not implemented for `i32`
    = note: required because of the requirements on the impl of `std::ops::Index<i32>` for `std::vec::Vec<isize>`
 
-error[E0277]: the trait bound `u8: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `u8`
   --> $DIR/integral-indexing.rs:12:5
    |
-LL |     s.as_bytes()[3u8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3u8];  //~ERROR : the type `[u8]` cannot be indexed by `u8`
    |     ^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `u8`
    = note: required because of the requirements on the impl of `std::ops::Index<u8>` for `[u8]`
 
-error[E0277]: the trait bound `i8: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `i8`
   --> $DIR/integral-indexing.rs:13:5
    |
-LL |     s.as_bytes()[3i8];  //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3i8];  //~ERROR : the type `[u8]` cannot be indexed by `i8`
    |     ^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `i8`
    = note: required because of the requirements on the impl of `std::ops::Index<i8>` for `[u8]`
 
-error[E0277]: the trait bound `u32: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `u32`
   --> $DIR/integral-indexing.rs:14:5
    |
-LL |     s.as_bytes()[3u32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3u32]; //~ERROR : the type `[u8]` cannot be indexed by `u32`
    |     ^^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `u32`
    = note: required because of the requirements on the impl of `std::ops::Index<u32>` for `[u8]`
 
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[u8]>` is not satisfied
+error[E0277]: the type `[u8]` cannot be indexed by `i32`
   --> $DIR/integral-indexing.rs:15:5
    |
-LL |     s.as_bytes()[3i32]; //~ERROR : std::slice::SliceIndex<[u8]>` is not satisfied
+LL |     s.as_bytes()[3i32]; //~ERROR : the type `[u8]` cannot be indexed by `i32`
    |     ^^^^^^^^^^^^^^^^^^ slice indices are of type `usize` or ranges of `usize`
    |
    = help: the trait `std::slice::SliceIndex<[u8]>` is not implemented for `i32`
diff --git a/src/test/ui/internal/auxiliary/internal_unstable.rs b/src/test/ui/internal/auxiliary/internal_unstable.rs
index 7cf54c3e6a69f..7c79dcb752272 100644
--- a/src/test/ui/internal/auxiliary/internal_unstable.rs
+++ b/src/test/ui/internal/auxiliary/internal_unstable.rs
@@ -23,14 +23,14 @@ pub struct Bar {
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
-#[allow_internal_unstable]
+#[allow_internal_unstable(function)]
 #[macro_export]
 macro_rules! call_unstable_allow {
     () => { $crate::unstable() }
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
-#[allow_internal_unstable]
+#[allow_internal_unstable(struct_field)]
 #[macro_export]
 macro_rules! construct_unstable_allow {
     ($e: expr) => {
@@ -39,21 +39,21 @@ macro_rules! construct_unstable_allow {
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
-#[allow_internal_unstable]
+#[allow_internal_unstable(method)]
 #[macro_export]
 macro_rules! call_method_allow {
     ($e: expr) => { $e.method() }
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
-#[allow_internal_unstable]
+#[allow_internal_unstable(struct_field, struct2_field)]
 #[macro_export]
 macro_rules! access_field_allow {
     ($e: expr) => { $e.x }
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
-#[allow_internal_unstable]
+#[allow_internal_unstable()]
 #[macro_export]
 macro_rules! pass_through_allow {
     ($e: expr) => { $e }
diff --git a/src/test/ui/internal/internal-unstable.rs b/src/test/ui/internal/internal-unstable.rs
index 34fef33bfeb97..e09a5d89172e8 100644
--- a/src/test/ui/internal/internal-unstable.rs
+++ b/src/test/ui/internal/internal-unstable.rs
@@ -13,7 +13,7 @@ macro_rules! foo {
     }}
 }
 
-#[allow_internal_unstable]
+#[allow_internal_unstable(function)]
 macro_rules! bar {
     ($e: expr) => {{
         foo!($e,
diff --git a/src/test/ui/issue-42944.rs b/src/test/ui/issue-42944.rs
new file mode 100644
index 0000000000000..9d746673f4dae
--- /dev/null
+++ b/src/test/ui/issue-42944.rs
@@ -0,0 +1,19 @@
+mod foo {
+    pub struct B(());
+}
+
+mod bar {
+    use foo::B;
+
+    fn foo() {
+        B(()); //~ ERROR expected function, found struct `B` [E0423]
+    }
+}
+
+mod baz {
+    fn foo() {
+        B(()); //~ ERROR cannot find function `B` in this scope [E0425]
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/issue-42944.stderr b/src/test/ui/issue-42944.stderr
new file mode 100644
index 0000000000000..43fd0ffb72439
--- /dev/null
+++ b/src/test/ui/issue-42944.stderr
@@ -0,0 +1,20 @@
+error[E0423]: expected function, found struct `B`
+  --> $DIR/issue-42944.rs:9:9
+   |
+LL |         B(()); //~ ERROR expected function, found struct `B` [E0423]
+   |         ^ constructor is not visible here due to private fields
+
+error[E0425]: cannot find function `B` in this scope
+  --> $DIR/issue-42944.rs:15:9
+   |
+LL |         B(()); //~ ERROR cannot find function `B` in this scope [E0425]
+   |         ^ not found in this scope
+help: possible candidate is found in another module, you can import it into scope
+   |
+LL |     use foo::B;
+   |
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0423, E0425.
+For more information about an error, try `rustc --explain E0423`.
diff --git a/src/test/ui/issue-53787-inline-assembler-macro.rs b/src/test/ui/issue-53787-inline-assembler-macro.rs
new file mode 100644
index 0000000000000..937bce1b655dd
--- /dev/null
+++ b/src/test/ui/issue-53787-inline-assembler-macro.rs
@@ -0,0 +1,23 @@
+// Regression test for Issue #53787: Fix ICE when creating a label in inline assembler with macros.
+
+#![feature(asm)]
+
+macro_rules! fake_jump {
+    ($id:expr) => {
+        unsafe {
+            asm!(
+            "
+            jmp $0
+            lea eax, [ebx]
+            xor eax, 0xDEADBEEF
+            retn
+            $0:
+            "::"0"($id)::"volatile", "intel");
+        }
+    };
+}
+
+fn main() {
+    fake_jump!("FirstFunc"); //~ ERROR invalid value for constraint in inline assembly
+    println!("Hello, world!");
+}
diff --git a/src/test/ui/issue-53787-inline-assembler-macro.stderr b/src/test/ui/issue-53787-inline-assembler-macro.stderr
new file mode 100644
index 0000000000000..69f380bdc9c03
--- /dev/null
+++ b/src/test/ui/issue-53787-inline-assembler-macro.stderr
@@ -0,0 +1,9 @@
+error[E0669]: invalid value for constraint in inline assembly
+  --> $DIR/issue-53787-inline-assembler-macro.rs:21:16
+   |
+LL |     fake_jump!("FirstFunc"); //~ ERROR invalid value for constraint in inline assembly
+   |                ^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0669`.
diff --git a/src/test/ui/issue-54943.rs b/src/test/ui/issue-54943.rs
index c720f62797580..ce4e010674359 100644
--- a/src/test/ui/issue-54943.rs
+++ b/src/test/ui/issue-54943.rs
@@ -1,7 +1,3 @@
-// compile-pass
-// FIXME(#54943) This test targets the scenario where proving the WF requirements of a user
-// type annotation requires checking dead code. This test should actually fail to compile.
-
 #![feature(nll)]
 #![allow(warnings)]
 
@@ -11,7 +7,7 @@ fn boo<'a>() {
     return;
 
     let x = foo::<&'a u32>();
-    //~^ ERROR the type `&'a u32` does not fulfill the required lifetime [E0477]
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/issue-54943.stderr b/src/test/ui/issue-54943.stderr
new file mode 100644
index 0000000000000..aa68177bcdb58
--- /dev/null
+++ b/src/test/ui/issue-54943.stderr
@@ -0,0 +1,11 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-54943.rs:9:13
+   |
+LL | fn boo<'a>() {
+   |        -- lifetime `'a` defined here
+...
+LL |     let x = foo::<&'a u32>();
+   |             ^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/issues/auxiliary/issue-52891.rs b/src/test/ui/issues/auxiliary/issue-52891.rs
new file mode 100644
index 0000000000000..0759811832242
--- /dev/null
+++ b/src/test/ui/issues/auxiliary/issue-52891.rs
@@ -0,0 +1,33 @@
+pub mod a {
+    pub mod inner {
+    }
+}
+
+pub mod b {
+    pub mod inner {
+    }
+}
+
+pub mod c {}
+
+pub mod d {}
+
+pub mod e {}
+
+pub mod f {}
+
+pub mod g {}
+
+pub mod h {}
+
+pub mod i {}
+
+pub mod j {}
+
+pub mod k {}
+
+pub mod l {}
+
+pub mod m {}
+
+pub mod n {}
diff --git a/src/test/ui/issues/auxiliary/issue-56943.rs b/src/test/ui/issues/auxiliary/issue-56943.rs
new file mode 100644
index 0000000000000..65b9beb91f90c
--- /dev/null
+++ b/src/test/ui/issues/auxiliary/issue-56943.rs
@@ -0,0 +1,3 @@
+pub struct S;
+mod m { pub struct S; }
+pub use crate::m::S as S2;
diff --git a/src/test/ui/issues/issue-11319.rs b/src/test/ui/issues/issue-11319.rs
index ea901205544b6..726c437355e53 100644
--- a/src/test/ui/issues/issue-11319.rs
+++ b/src/test/ui/issues/issue-11319.rs
@@ -1,12 +1,14 @@
 fn main() {
     match Some(10) {
-    //~^ ERROR match arms have incompatible types
-    //~| expected type `bool`
-    //~| found type `()`
-    //~| expected bool, found ()
+    //~^ NOTE `match` arms have incompatible types
         Some(5) => false,
+        //~^ NOTE this is found to be of type `bool`
         Some(2) => true,
+        //~^ NOTE this is found to be of type `bool`
         None    => (),
+        //~^ ERROR match arms have incompatible types
+        //~| NOTE expected bool, found ()
+        //~| NOTE expected type `bool`
         _       => true
     }
 }
diff --git a/src/test/ui/issues/issue-11319.stderr b/src/test/ui/issues/issue-11319.stderr
index 44d63ba3e6879..10db477b8ca7b 100644
--- a/src/test/ui/issues/issue-11319.stderr
+++ b/src/test/ui/issues/issue-11319.stderr
@@ -1,16 +1,20 @@
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-11319.rs:2:5
+  --> $DIR/issue-11319.rs:8:20
    |
 LL | /     match Some(10) {
-LL | |     //~^ ERROR match arms have incompatible types
-LL | |     //~| expected type `bool`
-LL | |     //~| found type `()`
-...  |
+LL | |     //~^ NOTE `match` arms have incompatible types
+LL | |         Some(5) => false,
+   | |                    ----- this is found to be of type `bool`
+LL | |         //~^ NOTE this is found to be of type `bool`
+LL | |         Some(2) => true,
+   | |                    ---- this is found to be of type `bool`
+LL | |         //~^ NOTE this is found to be of type `bool`
 LL | |         None    => (),
-   | |                    -- match arm with an incompatible type
+   | |                    ^^ expected bool, found ()
+...  |
 LL | |         _       => true
 LL | |     }
-   | |_____^ expected bool, found ()
+   | |_____- `match` arms have incompatible types
    |
    = note: expected type `bool`
               found type `()`
diff --git a/src/test/ui/issues/issue-12796.rs b/src/test/ui/issues/issue-12796.rs
index acd4584c73700..942d6b9a5686e 100644
--- a/src/test/ui/issues/issue-12796.rs
+++ b/src/test/ui/issues/issue-12796.rs
@@ -1,7 +1,7 @@
 trait Trait {
     fn outer(&self) {
         fn inner(_: &Self) {
-            //~^ ERROR can't use type parameters from outer function
+            //~^ ERROR can't use generic parameters from outer function
         }
     }
 }
diff --git a/src/test/ui/issues/issue-12796.stderr b/src/test/ui/issues/issue-12796.stderr
index 4bc29fd37dc4a..a01fd2d65420b 100644
--- a/src/test/ui/issues/issue-12796.stderr
+++ b/src/test/ui/issues/issue-12796.stderr
@@ -1,10 +1,10 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-12796.rs:3:22
    |
 LL |         fn inner(_: &Self) {
    |                      ^^^^
    |                      |
-   |                      use of type variable from outer function
+   |                      use of generic parameter from outer function
    |                      can't use `Self` here
 
 error: aborting due to previous error
diff --git a/src/test/ui/issues/issue-17385.nll.stderr b/src/test/ui/issues/issue-17385.nll.stderr
index 24080a3b387f2..20198f19dd5f5 100644
--- a/src/test/ui/issues/issue-17385.nll.stderr
+++ b/src/test/ui/issues/issue-17385.nll.stderr
@@ -1,23 +1,23 @@
 error[E0382]: use of moved value: `foo`
   --> $DIR/issue-17385.rs:19:11
    |
+LL |     let foo = X(1);
+   |         --- move occurs because `foo` has type `X`, which does not implement the `Copy` trait
 LL |     drop(foo);
    |          --- value moved here
 LL |     match foo { //~ ERROR use of moved value
 LL |         X(1) => (),
    |           ^ value used here after move
-   |
-   = note: move occurs because `foo` has type `X`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `e`
   --> $DIR/issue-17385.rs:25:11
    |
+LL |     let e = Enum::Variant2;
+   |         - move occurs because `e` has type `Enum`, which does not implement the `Copy` trait
 LL |     drop(e);
    |          - value moved here
 LL |     match e { //~ ERROR use of moved value
    |           ^ value used here after move
-   |
-   = note: move occurs because `e` has type `Enum`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-17458.rs b/src/test/ui/issues/issue-17458.rs
index d7a1752b96c44..444e94d829bf8 100644
--- a/src/test/ui/issues/issue-17458.rs
+++ b/src/test/ui/issues/issue-17458.rs
@@ -1,4 +1,4 @@
-static X: usize = 0 as *const usize as usize;
+static X: usize = unsafe { 0 as *const usize as usize };
 //~^ ERROR: casting pointers to integers in statics is unstable
 
 fn main() {
diff --git a/src/test/ui/issues/issue-17458.stderr b/src/test/ui/issues/issue-17458.stderr
index 04921419ae01a..a1a8ed9f0cdcb 100644
--- a/src/test/ui/issues/issue-17458.stderr
+++ b/src/test/ui/issues/issue-17458.stderr
@@ -1,8 +1,8 @@
 error[E0658]: casting pointers to integers in statics is unstable (see issue #51910)
-  --> $DIR/issue-17458.rs:1:19
+  --> $DIR/issue-17458.rs:1:28
    |
-LL | static X: usize = 0 as *const usize as usize;
-   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | static X: usize = unsafe { 0 as *const usize as usize };
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
diff --git a/src/test/ui/issues/issue-17718-const-bad-values.stderr b/src/test/ui/issues/issue-17718-const-bad-values.stderr
index 25b1cfb0ffb00..95ef2b1b01008 100644
--- a/src/test/ui/issues/issue-17718-const-bad-values.stderr
+++ b/src/test/ui/issues/issue-17718-const-bad-values.stderr
@@ -4,17 +4,17 @@ error[E0017]: references in constants may only refer to immutable values
 LL | const C1: &'static mut [usize] = &mut [];
    |                                  ^^^^^^^ constants require immutable values
 
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0017]: references in constants may only refer to immutable values
   --> $DIR/issue-17718-const-bad-values.rs:5:41
    |
 LL | const C2: &'static mut usize = unsafe { &mut S };
-   |                                         ^^^^^^
+   |                                         ^^^^^^ constants require immutable values
 
-error[E0017]: references in constants may only refer to immutable values
+error[E0013]: constants cannot refer to statics, use a constant instead
   --> $DIR/issue-17718-const-bad-values.rs:5:41
    |
 LL | const C2: &'static mut usize = unsafe { &mut S };
-   |                                         ^^^^^^ constants require immutable values
+   |                                         ^^^^^^
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/issues/issue-17728.rs b/src/test/ui/issues/issue-17728.rs
index 0f13ae3304d6c..15cea1d609d53 100644
--- a/src/test/ui/issues/issue-17728.rs
+++ b/src/test/ui/issues/issue-17728.rs
@@ -97,7 +97,7 @@ impl Debug for Player {
 }
 
 fn str_to_direction(to_parse: &str) -> RoomDirection {
-    match to_parse { //~ ERROR match arms have incompatible types
+    match to_parse {
         "w" | "west" => RoomDirection::West,
         "e" | "east" => RoomDirection::East,
         "n" | "north" => RoomDirection::North,
@@ -108,6 +108,7 @@ fn str_to_direction(to_parse: &str) -> RoomDirection {
         "down" => RoomDirection::Down,
         _ => None
     }
+        //~^^ ERROR match arms have incompatible types
 }
 
 fn main() {
diff --git a/src/test/ui/issues/issue-17728.stderr b/src/test/ui/issues/issue-17728.stderr
index 355868f05690f..2c2efad19f569 100644
--- a/src/test/ui/issues/issue-17728.stderr
+++ b/src/test/ui/issues/issue-17728.stderr
@@ -10,17 +10,19 @@ LL |             Some(entry) => Ok(entry),
    |                            ^^^^^^^^^ ...but data from `room` is returned here
 
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-17728.rs:100:5
+  --> $DIR/issue-17728.rs:109:14
    |
-LL | /     match to_parse { //~ ERROR match arms have incompatible types
+LL | /     match to_parse {
 LL | |         "w" | "west" => RoomDirection::West,
 LL | |         "e" | "east" => RoomDirection::East,
 LL | |         "n" | "north" => RoomDirection::North,
 ...  |
+LL | |         "down" => RoomDirection::Down,
+   | |                   ------------------- this and all prior arms are found to be of type `RoomDirection`
 LL | |         _ => None
-   | |              ---- match arm with an incompatible type
+   | |              ^^^^ expected enum `RoomDirection`, found enum `std::option::Option`
 LL | |     }
-   | |_____^ expected enum `RoomDirection`, found enum `std::option::Option`
+   | |_____- `match` arms have incompatible types
    |
    = note: expected type `RoomDirection`
               found type `std::option::Option<_>`
diff --git a/src/test/ui/issues/issue-17999.stderr b/src/test/ui/issues/issue-17999.stderr
index 3f32dc1540232..51c0c757a80c1 100644
--- a/src/test/ui/issues/issue-17999.stderr
+++ b/src/test/ui/issues/issue-17999.stderr
@@ -2,7 +2,7 @@ error: unused variable: `x`
   --> $DIR/issue-17999.rs:5:13
    |
 LL |         let x = (); //~ ERROR: unused variable: `x`
-   |             ^ help: consider using `_x` instead
+   |             ^ help: consider prefixing with an underscore: `_x`
    |
 note: lint level defined here
   --> $DIR/issue-17999.rs:1:9
@@ -14,7 +14,7 @@ error: unused variable: `a`
   --> $DIR/issue-17999.rs:7:13
    |
 LL |             a => {} //~ ERROR: unused variable: `a`
-   |             ^ help: consider using `_a` instead
+   |             ^ help: consider prefixing with an underscore: `_a`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-18294.rs b/src/test/ui/issues/issue-18294.rs
index df4fd1642f2bc..1c2229fb9eae4 100644
--- a/src/test/ui/issues/issue-18294.rs
+++ b/src/test/ui/issues/issue-18294.rs
@@ -1,5 +1,5 @@
 fn main() {
     const X: u32 = 1;
-    const Y: usize = &X as *const u32 as usize; //~ ERROR is unstable
+    const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR is unstable
     println!("{}", Y);
 }
diff --git a/src/test/ui/issues/issue-18294.stderr b/src/test/ui/issues/issue-18294.stderr
index 2af7f45628e37..f3e8ab1a31307 100644
--- a/src/test/ui/issues/issue-18294.stderr
+++ b/src/test/ui/issues/issue-18294.stderr
@@ -1,8 +1,8 @@
 error[E0658]: casting pointers to integers in constants is unstable (see issue #51910)
-  --> $DIR/issue-18294.rs:3:22
+  --> $DIR/issue-18294.rs:3:31
    |
-LL |     const Y: usize = &X as *const u32 as usize; //~ ERROR is unstable
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     const Y: usize = unsafe { &X as *const u32 as usize }; //~ ERROR is unstable
+   |                               ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(const_raw_ptr_to_usize_cast)] to the crate attributes to enable
 
diff --git a/src/test/ui/issues/issue-20413.stderr b/src/test/ui/issues/issue-20413.stderr
index 20e57583f1daa..1c353fec8aabf 100644
--- a/src/test/ui/issues/issue-20413.stderr
+++ b/src/test/ui/issues/issue-20413.stderr
@@ -6,7 +6,7 @@ LL | struct NoData<T>;
    |
    = help: consider removing `T` or using a marker such as `std::marker::PhantomData`
 
-error[E0275]: overflow evaluating the requirement `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: std::marker::Sized`
+error[E0275]: overflow evaluating the requirement `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Foo`
   --> $DIR/issue-20413.rs:8:1
    |
 LL | / impl<T> Foo for T where NoData<T>: Foo {
@@ -18,7 +18,6 @@ LL | | }
    | |_^
    |
    = help: consider adding a `#![recursion_limit="128"]` attribute to your crate
-   = note: required because of the requirements on the impl of `Foo` for `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
    = note: required because of the requirements on the impl of `Foo` for `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`
diff --git a/src/test/ui/issues/issue-20616-3.rs b/src/test/ui/issues/issue-20616-3.rs
index e84506ee249d2..9bfd5bf231302 100644
--- a/src/test/ui/issues/issue-20616-3.rs
+++ b/src/test/ui/issues/issue-20616-3.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -12,7 +10,8 @@ type Type_1_<'a, T> = &'a T;
 //type Type_2 = Type_1_<'static ()>; // error: expected `,` or `>` after lifetime name, found `(`
 
 
-type Type_3<T> = Box<T,,>; //~ error: expected one of `>`, identifier, lifetime, or type, found `,`
+type Type_3<T> = Box<T,,>;
+//~^ error: expected one of `>`, const, identifier, lifetime, or type, found `,`
 
 
 //type Type_4<T> = Type_1_<'static,, T>; // error: expected type, found `,`
diff --git a/src/test/ui/issues/issue-20616-3.stderr b/src/test/ui/issues/issue-20616-3.stderr
index 5247298b7cc26..f51fb949c740c 100644
--- a/src/test/ui/issues/issue-20616-3.stderr
+++ b/src/test/ui/issues/issue-20616-3.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, lifetime, or type, found `,`
-  --> $DIR/issue-20616-3.rs:15:24
+error: expected one of `>`, const, identifier, lifetime, or type, found `,`
+  --> $DIR/issue-20616-3.rs:13:24
    |
-LL | type Type_3<T> = Box<T,,>; //~ error: expected one of `>`, identifier, lifetime, or type, found `,`
-   |                        ^ expected one of `>`, identifier, lifetime, or type here
+LL | type Type_3<T> = Box<T,,>;
+   |                        ^ expected one of `>`, const, identifier, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-4.rs b/src/test/ui/issues/issue-20616-4.rs
index 785a6fa7d9a2f..e9a34a04667b0 100644
--- a/src/test/ui/issues/issue-20616-4.rs
+++ b/src/test/ui/issues/issue-20616-4.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -16,7 +14,7 @@ type Type_1_<'a, T> = &'a T;
 
 
 type Type_4<T> = Type_1_<'static,, T>;
-//~^ error: expected one of `>`, identifier, lifetime, or type, found `,`
+//~^ error: expected one of `>`, const, identifier, lifetime, or type, found `,`
 
 
 type Type_5_<'a> = Type_1_<'a, ()>;
diff --git a/src/test/ui/issues/issue-20616-4.stderr b/src/test/ui/issues/issue-20616-4.stderr
index 74c38d9e97d60..22a655465e83c 100644
--- a/src/test/ui/issues/issue-20616-4.stderr
+++ b/src/test/ui/issues/issue-20616-4.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, lifetime, or type, found `,`
-  --> $DIR/issue-20616-4.rs:18:34
+error: expected one of `>`, const, identifier, lifetime, or type, found `,`
+  --> $DIR/issue-20616-4.rs:16:34
    |
 LL | type Type_4<T> = Type_1_<'static,, T>;
-   |                                  ^ expected one of `>`, identifier, lifetime, or type here
+   |                                  ^ expected one of `>`, const, identifier, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-5.rs b/src/test/ui/issues/issue-20616-5.rs
index 71dcc1f3a024f..23862516d2cbf 100644
--- a/src/test/ui/issues/issue-20616-5.rs
+++ b/src/test/ui/issues/issue-20616-5.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -22,7 +20,7 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 
 
 type Type_5<'a> = Type_1_<'a, (),,>;
-//~^ error: expected one of `>`, identifier, lifetime, or type, found `,`
+//~^ error: expected one of `>`, const, identifier, lifetime, or type, found `,`
 
 
 //type Type_6 = Type_5_<'a,,>; // error: expected type, found `,`
diff --git a/src/test/ui/issues/issue-20616-5.stderr b/src/test/ui/issues/issue-20616-5.stderr
index 38457beadc448..d83fc41f43ec0 100644
--- a/src/test/ui/issues/issue-20616-5.stderr
+++ b/src/test/ui/issues/issue-20616-5.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, lifetime, or type, found `,`
-  --> $DIR/issue-20616-5.rs:24:34
+error: expected one of `>`, const, identifier, lifetime, or type, found `,`
+  --> $DIR/issue-20616-5.rs:22:34
    |
 LL | type Type_5<'a> = Type_1_<'a, (),,>;
-   |                                  ^ expected one of `>`, identifier, lifetime, or type here
+   |                                  ^ expected one of `>`, const, identifier, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-6.rs b/src/test/ui/issues/issue-20616-6.rs
index da32da4885242..dc327f3f78824 100644
--- a/src/test/ui/issues/issue-20616-6.rs
+++ b/src/test/ui/issues/issue-20616-6.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -25,7 +23,7 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 
 
 type Type_6 = Type_5_<'a,,>;
-//~^ error: expected one of `>`, identifier, lifetime, or type, found `,`
+//~^ error: expected one of `>`, const, identifier, lifetime, or type, found `,`
 
 
 //type Type_7 = Box<(),,>; // error: expected type, found `,`
diff --git a/src/test/ui/issues/issue-20616-6.stderr b/src/test/ui/issues/issue-20616-6.stderr
index 55b1d031a3915..0740df595234a 100644
--- a/src/test/ui/issues/issue-20616-6.stderr
+++ b/src/test/ui/issues/issue-20616-6.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, lifetime, or type, found `,`
-  --> $DIR/issue-20616-6.rs:27:26
+error: expected one of `>`, const, identifier, lifetime, or type, found `,`
+  --> $DIR/issue-20616-6.rs:25:26
    |
 LL | type Type_6 = Type_5_<'a,,>;
-   |                          ^ expected one of `>`, identifier, lifetime, or type here
+   |                          ^ expected one of `>`, const, identifier, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-7.rs b/src/test/ui/issues/issue-20616-7.rs
index feaaff2c89025..ffd1620c1d306 100644
--- a/src/test/ui/issues/issue-20616-7.rs
+++ b/src/test/ui/issues/issue-20616-7.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -27,7 +25,8 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 //type Type_6 = Type_5_<'a,,>; // error: expected type, found `,`
 
 
-type Type_7 = Box<(),,>; //~ error: expected one of `>`, identifier, lifetime, or type, found `,`
+type Type_7 = Box<(),,>;
+//~^ error: expected one of `>`, const, identifier, lifetime, or type, found `,`
 
 
 //type Type_8<'a,,> = &'a (); // error: expected ident, found `,`
diff --git a/src/test/ui/issues/issue-20616-7.stderr b/src/test/ui/issues/issue-20616-7.stderr
index 8b5f67c703f64..c0e108375be29 100644
--- a/src/test/ui/issues/issue-20616-7.stderr
+++ b/src/test/ui/issues/issue-20616-7.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, lifetime, or type, found `,`
-  --> $DIR/issue-20616-7.rs:30:22
+error: expected one of `>`, const, identifier, lifetime, or type, found `,`
+  --> $DIR/issue-20616-7.rs:28:22
    |
-LL | type Type_7 = Box<(),,>; //~ error: expected one of `>`, identifier, lifetime, or type, found `,`
-   |                      ^ expected one of `>`, identifier, lifetime, or type here
+LL | type Type_7 = Box<(),,>;
+   |                      ^ expected one of `>`, const, identifier, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-8.rs b/src/test/ui/issues/issue-20616-8.rs
index 2fc7243559a31..c9e8b61e50b52 100644
--- a/src/test/ui/issues/issue-20616-8.rs
+++ b/src/test/ui/issues/issue-20616-8.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -30,7 +28,8 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 //type Type_7 = Box<(),,>; // error: expected type, found `,`
 
 
-type Type_8<'a,,> = &'a (); //~ error: expected one of `>`, identifier, or lifetime, found `,`
+type Type_8<'a,,> = &'a ();
+//~^ error: expected one of `>`, `const`, identifier, or lifetime, found `,`
 
 
 //type Type_9<T,,> = Box<T>; // error: expected identifier, found `,`
diff --git a/src/test/ui/issues/issue-20616-8.stderr b/src/test/ui/issues/issue-20616-8.stderr
index cdeb544f07c4c..0ef9192f1e73a 100644
--- a/src/test/ui/issues/issue-20616-8.stderr
+++ b/src/test/ui/issues/issue-20616-8.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, or lifetime, found `,`
-  --> $DIR/issue-20616-8.rs:33:16
+error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+  --> $DIR/issue-20616-8.rs:31:16
    |
-LL | type Type_8<'a,,> = &'a (); //~ error: expected one of `>`, identifier, or lifetime, found `,`
-   |                ^ expected one of `>`, identifier, or lifetime here
+LL | type Type_8<'a,,> = &'a ();
+   |                ^ expected one of `>`, `const`, identifier, or lifetime here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20616-9.rs b/src/test/ui/issues/issue-20616-9.rs
index b14a5b0ff36da..1c509f26fd63a 100644
--- a/src/test/ui/issues/issue-20616-9.rs
+++ b/src/test/ui/issues/issue-20616-9.rs
@@ -1,8 +1,6 @@
 // We need all these 9 issue-20616-N.rs files
 // because we can only catch one parsing error at a time
 
-
-
 type Type_1_<'a, T> = &'a T;
 
 
@@ -33,4 +31,5 @@ type Type_5_<'a> = Type_1_<'a, ()>;
 //type Type_8<'a,,> = &'a (); // error: expected identifier, found `,`
 
 
-type Type_9<T,,> = Box<T>; //~ error: expected one of `>`, identifier, or lifetime, found `,`
+type Type_9<T,,> = Box<T>;
+//~^ error: expected one of `>`, `const`, identifier, or lifetime, found `,`
diff --git a/src/test/ui/issues/issue-20616-9.stderr b/src/test/ui/issues/issue-20616-9.stderr
index dfe705c6f12ed..5fd1400a2e8ca 100644
--- a/src/test/ui/issues/issue-20616-9.stderr
+++ b/src/test/ui/issues/issue-20616-9.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, or lifetime, found `,`
-  --> $DIR/issue-20616-9.rs:36:15
+error: expected one of `>`, `const`, identifier, or lifetime, found `,`
+  --> $DIR/issue-20616-9.rs:34:15
    |
-LL | type Type_9<T,,> = Box<T>; //~ error: expected one of `>`, identifier, or lifetime, found `,`
-   |               ^ expected one of `>`, identifier, or lifetime here
+LL | type Type_9<T,,> = Box<T>;
+   |               ^ expected one of `>`, `const`, identifier, or lifetime here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-20797.rs b/src/test/ui/issues/issue-20797.rs
index ce8564ffe43ad..e504b4705daf2 100644
--- a/src/test/ui/issues/issue-20797.rs
+++ b/src/test/ui/issues/issue-20797.rs
@@ -17,7 +17,7 @@ impl PathExtensions for PathBuf {}
 /// A strategy for acquiring more subpaths to walk.
 pub trait Strategy {
     type P: PathExtensions;
-    /// Get additional subpaths from a given path.
+    /// Gets additional subpaths from a given path.
     fn get_more(&self, item: &Self::P) -> io::Result<Vec<Self::P>>;
     /// Determine whether a path should be walked further.
     /// This is run against each item from `get_more()`.
@@ -44,7 +44,7 @@ pub struct Subpaths<S: Strategy> {
 }
 
 impl<S: Strategy> Subpaths<S> {
-    /// Create a directory walker with a root path and strategy.
+    /// Creates a directory walker with a root path and strategy.
     pub fn new(p: &S::P, strategy: S) -> io::Result<Subpaths<S>> {
         let stack = strategy.get_more(p)?;
         Ok(Subpaths { stack: stack, strategy: strategy })
@@ -52,7 +52,7 @@ impl<S: Strategy> Subpaths<S> {
 }
 
 impl<S: Default + Strategy> Subpaths<S> {
-    /// Create a directory walker with a root path and a default strategy.
+    /// Creates a directory walker with a root path and a default strategy.
     pub fn walk(p: &S::P) -> io::Result<Subpaths<S>> {
         Subpaths::new(p, Default::default())
     }
diff --git a/src/test/ui/issues/issue-22599.stderr b/src/test/ui/issues/issue-22599.stderr
index 5c2ed7455f132..bc4949da6f785 100644
--- a/src/test/ui/issues/issue-22599.stderr
+++ b/src/test/ui/issues/issue-22599.stderr
@@ -2,7 +2,7 @@ error: unused variable: `a`
   --> $DIR/issue-22599.rs:8:19
    |
 LL |     v = match 0 { a => 0 }; //~ ERROR: unused variable: `a`
-   |                   ^ help: consider using `_a` instead
+   |                   ^ help: consider prefixing with an underscore: `_a`
    |
 note: lint level defined here
   --> $DIR/issue-22599.rs:1:9
diff --git a/src/test/ui/issues/issue-23217.stderr b/src/test/ui/issues/issue-23217.stderr
index 208d0cc499a80..9cad002036fff 100644
--- a/src/test/ui/issues/issue-23217.stderr
+++ b/src/test/ui/issues/issue-23217.stderr
@@ -5,10 +5,9 @@ LL | pub enum SomeEnum {
    | ----------------- variant `A` not found here
 LL |     B = SomeEnum::A,
    |         ----------^
-   |         |
+   |         |         |
+   |         |         help: did you mean: `B`
    |         variant not found in `SomeEnum`
-   |
-   = help: did you mean `B`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-23589.rs b/src/test/ui/issues/issue-23589.rs
index a59710a1a3cde..1c640af8d02b9 100644
--- a/src/test/ui/issues/issue-23589.rs
+++ b/src/test/ui/issues/issue-23589.rs
@@ -1,4 +1,5 @@
 fn main() {
     let v: Vec(&str) = vec!['1', '2'];
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
+    //~| ERROR mismatched types
 }
diff --git a/src/test/ui/issues/issue-23589.stderr b/src/test/ui/issues/issue-23589.stderr
index e6e07c167f349..bc2007ba39cc6 100644
--- a/src/test/ui/issues/issue-23589.stderr
+++ b/src/test/ui/issues/issue-23589.stderr
@@ -1,9 +1,22 @@
-error[E0214]: parenthesized parameters may only be used with a trait
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-23589.rs:2:15
    |
 LL |     let v: Vec(&str) = vec!['1', '2'];
-   |               ^^^^^^ only traits may use parentheses
+   |               ^^^^^^
+   |               |
+   |               only `Fn` traits may use parentheses
+   |               help: use angle brackets instead: `<&str>`
 
-error: aborting due to previous error
+error[E0308]: mismatched types
+  --> $DIR/issue-23589.rs:2:29
+   |
+LL |     let v: Vec(&str) = vec!['1', '2'];
+   |                             ^^^ expected &str, found char
+   |
+   = note: expected type `&str`
+              found type `char`
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0214`.
+Some errors occurred: E0214, E0308.
+For more information about an error, try `rustc --explain E0214`.
diff --git a/src/test/ui/issues/issue-24036.rs b/src/test/ui/issues/issue-24036.rs
index 3642085934abe..2f501b941b5a6 100644
--- a/src/test/ui/issues/issue-24036.rs
+++ b/src/test/ui/issues/issue-24036.rs
@@ -6,11 +6,11 @@ fn closure_to_loc() {
 
 fn closure_from_match() {
     let x = match 1usize {
-    //~^ ERROR match arms have incompatible types
         1 => |c| c + 1,
         2 => |c| c - 1,
         _ => |c| c - 1
     };
+    //~^^^ ERROR match arms have incompatible types
 }
 
 fn main() { }
diff --git a/src/test/ui/issues/issue-24036.stderr b/src/test/ui/issues/issue-24036.stderr
index 9f799c9b45069..fa9935fcf619d 100644
--- a/src/test/ui/issues/issue-24036.stderr
+++ b/src/test/ui/issues/issue-24036.stderr
@@ -10,20 +10,20 @@ LL |     x = |c| c + 1;
    = help: consider boxing your closure and/or using it as a trait object
 
 error[E0308]: match arms have incompatible types
-  --> $DIR/issue-24036.rs:8:13
+  --> $DIR/issue-24036.rs:10:14
    |
 LL |       let x = match 1usize {
-   |  _____________^
-LL | |     //~^ ERROR match arms have incompatible types
+   |  _____________-
 LL | |         1 => |c| c + 1,
+   | |              --------- this is found to be of type `[closure@$DIR/issue-24036.rs:9:14: 9:23]`
 LL | |         2 => |c| c - 1,
-   | |              --------- match arm with an incompatible type
+   | |              ^^^^^^^^^ expected closure, found a different closure
 LL | |         _ => |c| c - 1
 LL | |     };
-   | |_____^ expected closure, found a different closure
+   | |_____- `match` arms have incompatible types
    |
-   = note: expected type `[closure@$DIR/issue-24036.rs:10:14: 10:23]`
-              found type `[closure@$DIR/issue-24036.rs:11:14: 11:23]`
+   = note: expected type `[closure@$DIR/issue-24036.rs:9:14: 9:23]`
+              found type `[closure@$DIR/issue-24036.rs:10:14: 10:23]`
    = note: no two closures, even if identical, have the same type
    = help: consider boxing your closure and/or using it as a trait object
 
diff --git a/src/test/ui/issues/issue-24357.nll.stderr b/src/test/ui/issues/issue-24357.nll.stderr
index 06de9537af031..310535434cd08 100644
--- a/src/test/ui/issues/issue-24357.nll.stderr
+++ b/src/test/ui/issues/issue-24357.nll.stderr
@@ -1,6 +1,8 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/issue-24357.rs:6:12
    |
+LL |    let x = NoCopy;
+   |        - move occurs because `x` has type `NoCopy`, which does not implement the `Copy` trait
 LL |    let f = move || { let y = x; };
    |            -------           - variable moved due to use in closure
    |            |
@@ -8,8 +10,6 @@ LL |    let f = move || { let y = x; };
 LL |    //~^ NOTE value moved (into closure) here
 LL |    let z = x;
    |            ^ value used here after move
-   |
-   = note: move occurs because `x` has type `NoCopy`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-25700.nll.stderr b/src/test/ui/issues/issue-25700.nll.stderr
new file mode 100644
index 0000000000000..ba5403cca4d06
--- /dev/null
+++ b/src/test/ui/issues/issue-25700.nll.stderr
@@ -0,0 +1,13 @@
+error[E0382]: use of moved value: `t`
+  --> $DIR/issue-25700.rs:13:10
+   |
+LL |     let t = S::<()>(None);
+   |         - move occurs because `t` has type `S<()>`, which does not implement the `Copy` trait
+LL |     drop(t);
+   |          - value moved here
+LL |     drop(t); //~ ERROR use of moved value
+   |          ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/issues/issue-25826.rs b/src/test/ui/issues/issue-25826.rs
index e6022653d9c3b..36a69cf4c22ff 100644
--- a/src/test/ui/issues/issue-25826.rs
+++ b/src/test/ui/issues/issue-25826.rs
@@ -1,6 +1,6 @@
 fn id<T>(t: T) -> T { t }
 fn main() {
-    const A: bool = id::<u8> as *const () < id::<u16> as *const ();
+    const A: bool = unsafe { id::<u8> as *const () < id::<u16> as *const () };
     //~^ ERROR comparing raw pointers inside constant
     println!("{}", A);
 }
diff --git a/src/test/ui/issues/issue-25826.stderr b/src/test/ui/issues/issue-25826.stderr
index 73ebf29d08e78..dc547f7c32c94 100644
--- a/src/test/ui/issues/issue-25826.stderr
+++ b/src/test/ui/issues/issue-25826.stderr
@@ -1,8 +1,8 @@
 error[E0658]: comparing raw pointers inside constant (see issue #53020)
-  --> $DIR/issue-25826.rs:3:21
+  --> $DIR/issue-25826.rs:3:30
    |
-LL |     const A: bool = id::<u8> as *const () < id::<u16> as *const ();
-   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     const A: bool = unsafe { id::<u8> as *const () < id::<u16> as *const () };
+   |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add #![feature(const_compare_raw_pointers)] to the crate attributes to enable
 
diff --git a/src/test/ui/issues/issue-26548.stderr b/src/test/ui/issues/issue-26548.stderr
index 84604f31d1e7f..ff197eeeb0fe9 100644
--- a/src/test/ui/issues/issue-26548.stderr
+++ b/src/test/ui/issues/issue-26548.stderr
@@ -1,6 +1,6 @@
 error[E0391]: cycle detected when computing layout of `std::option::Option<S>`
    |
-note: ...which requires computing layout of `S`...
+   = note: ...which requires computing layout of `S`...
    = note: ...which again requires computing layout of `std::option::Option<S>`, completing the cycle
 note: cycle used when processing `main`
   --> $DIR/issue-26548.rs:9:1
diff --git a/src/test/ui/issues/issue-26886.stderr b/src/test/ui/issues/issue-26886.stderr
index 08faa9c9ca2c2..70dacb353fe07 100644
--- a/src/test/ui/issues/issue-26886.stderr
+++ b/src/test/ui/issues/issue-26886.stderr
@@ -4,13 +4,12 @@ error[E0252]: the name `Arc` is defined multiple times
 LL | use std::sync::{self, Arc};
    |                       --- previous import of the type `Arc` here
 LL | use std::sync::Arc; //~ ERROR the name `Arc` is defined multiple times
-   |     ^^^^^^^^^^^^^^ `Arc` reimported here
+   | ----^^^^^^^^^^^^^^-
+   | |   |
+   | |   `Arc` reimported here
+   | help: remove unnecessary import
    |
    = note: `Arc` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use std::sync::Arc as OtherArc; //~ ERROR the name `Arc` is defined multiple times
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0252]: the name `sync` is defined multiple times
   --> $DIR/issue-26886.rs:4:5
@@ -19,13 +18,12 @@ LL | use std::sync::{self, Arc};
    |                 ---- previous import of the module `sync` here
 ...
 LL | use std::sync; //~ ERROR the name `sync` is defined multiple times
-   |     ^^^^^^^^^ `sync` reimported here
+   | ----^^^^^^^^^-
+   | |   |
+   | |   `sync` reimported here
+   | help: remove unnecessary import
    |
    = note: `sync` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use std::sync as other_sync; //~ ERROR the name `sync` is defined multiple times
-   |     ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr b/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr
index 8ea2bdb693d31..6993419326c8e 100644
--- a/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr
+++ b/src/test/ui/issues/issue-27282-move-match-input-into-guard.stderr
@@ -1,6 +1,9 @@
 error[E0382]: use of moved value: `b`
   --> $DIR/issue-27282-move-match-input-into-guard.rs:18:14
    |
+LL |     let b = &mut true;
+   |         - move occurs because `b` has type `&mut bool`, which does not implement the `Copy` trait
+...
 LL |         _ if { (|| { let bar = b; *bar = false; })();
    |                 --             - variable moved due to use in closure
    |                 |
@@ -8,8 +11,6 @@ LL |         _ if { (|| { let bar = b; *bar = false; })();
 LL |                      false } => { },
 LL |         &mut true => { println!("You might think we should get here"); },
    |              ^^^^ value used here after move
-   |
-   = note: move occurs because `b` has type `&mut bool`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-27433.rs b/src/test/ui/issues/issue-27433.rs
index 2cc7d05e7c691..156ae68efe2c5 100644
--- a/src/test/ui/issues/issue-27433.rs
+++ b/src/test/ui/issues/issue-27433.rs
@@ -1,5 +1,5 @@
 fn main() {
     let foo = 42u32;
     const FOO : u32 = foo;
-                   //~^ ERROR can't capture dynamic environment
+                   //~^ ERROR attempt to use a non-constant value in a constant
 }
diff --git a/src/test/ui/issues/issue-27433.stderr b/src/test/ui/issues/issue-27433.stderr
index 78a193dd99a7f..e232d17e6d7a6 100644
--- a/src/test/ui/issues/issue-27433.stderr
+++ b/src/test/ui/issues/issue-27433.stderr
@@ -1,11 +1,9 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/issue-27433.rs:3:23
    |
 LL |     const FOO : u32 = foo;
-   |                       ^^^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                       ^^^ non-constant value
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0434`.
+For more information about this error, try `rustc --explain E0435`.
diff --git a/src/test/ui/issues/issue-28344.stderr b/src/test/ui/issues/issue-28344.stderr
index 146ebad6ce175..b6f520c644b32 100644
--- a/src/test/ui/issues/issue-28344.stderr
+++ b/src/test/ui/issues/issue-28344.stderr
@@ -11,8 +11,7 @@ LL |     let x: u8 = BitXor::bitor(0 as u8, 0 as u8);
    |                 --------^^^^^
    |                 |
    |                 function or associated item not found in `dyn std::ops::BitXor<_>`
-   |
-   = help: did you mean `bitxor`?
+   |                 help: did you mean: `bitxor`
 
 error[E0191]: the value of the associated type `Output` (from the trait `std::ops::BitXor`) must be specified
   --> $DIR/issue-28344.rs:8:13
@@ -27,8 +26,7 @@ LL |     let g = BitXor::bitor;
    |             --------^^^^^
    |             |
    |             function or associated item not found in `dyn std::ops::BitXor<_>`
-   |
-   = help: did you mean `bitxor`?
+   |             help: did you mean: `bitxor`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/issues/issue-28971.stderr b/src/test/ui/issues/issue-28971.stderr
index d5dbd5f64885c..77d0b53ad216b 100644
--- a/src/test/ui/issues/issue-28971.stderr
+++ b/src/test/ui/issues/issue-28971.stderr
@@ -5,9 +5,10 @@ LL | enum Foo {
    | -------- variant `Baz` not found here
 ...
 LL |             Foo::Baz(..) => (),
-   |             -----^^^---- variant not found in `Foo`
-   |
-   = help: did you mean `Bar`?
+   |             -----^^^----
+   |             |    |
+   |             |    help: did you mean: `Bar`
+   |             variant not found in `Foo`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-29723.stderr b/src/test/ui/issues/issue-29723.stderr
index de858aec881f7..7928af5d5a5cd 100644
--- a/src/test/ui/issues/issue-29723.stderr
+++ b/src/test/ui/issues/issue-29723.stderr
@@ -1,13 +1,14 @@
 error[E0382]: use of moved value: `s`
   --> $DIR/issue-29723.rs:12:13
    |
+LL |     let s = String::new();
+   |         - move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
+LL |     let _s = match 0 {
 LL |         0 if { drop(s); false } => String::from("oops"),
    |                     - value moved here
 ...
 LL |             s
    |             ^ value used here after move
-   |
-   = note: move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-3021-c.rs b/src/test/ui/issues/issue-3021-c.rs
index 491336206ca94..94ed1fdf78191 100644
--- a/src/test/ui/issues/issue-3021-c.rs
+++ b/src/test/ui/issues/issue-3021-c.rs
@@ -1,8 +1,8 @@
 fn siphash<T>() {
 
     trait U {
-        fn g(&self, x: T) -> T;  //~ ERROR can't use type parameters from outer function
-        //~^ ERROR can't use type parameters from outer function
+        fn g(&self, x: T) -> T;  //~ ERROR can't use generic parameters from outer function
+        //~^ ERROR can't use generic parameters from outer function
     }
 }
 
diff --git a/src/test/ui/issues/issue-3021-c.stderr b/src/test/ui/issues/issue-3021-c.stderr
index 323ce4fa30613..5eadf7837c7d0 100644
--- a/src/test/ui/issues/issue-3021-c.stderr
+++ b/src/test/ui/issues/issue-3021-c.stderr
@@ -1,24 +1,24 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-3021-c.rs:4:24
    |
 LL | fn siphash<T>() {
    |            - type variable from outer function
 ...
-LL |         fn g(&self, x: T) -> T;  //~ ERROR can't use type parameters from outer function
-   |            -           ^ use of type variable from outer function
+LL |         fn g(&self, x: T) -> T;  //~ ERROR can't use generic parameters from outer function
+   |            -           ^ use of generic parameter from outer function
    |            |
-   |            help: try using a local type parameter instead: `g<T>`
+   |            help: try using a local generic parameter instead: `g<T>`
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-3021-c.rs:4:30
    |
 LL | fn siphash<T>() {
    |            - type variable from outer function
 ...
-LL |         fn g(&self, x: T) -> T;  //~ ERROR can't use type parameters from outer function
-   |            -                 ^ use of type variable from outer function
+LL |         fn g(&self, x: T) -> T;  //~ ERROR can't use generic parameters from outer function
+   |            -                 ^ use of generic parameter from outer function
    |            |
-   |            help: try using a local type parameter instead: `g<T>`
+   |            help: try using a local generic parameter instead: `g<T>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-3214.rs b/src/test/ui/issues/issue-3214.rs
index 85eae2686e6a9..9a727aa305797 100644
--- a/src/test/ui/issues/issue-3214.rs
+++ b/src/test/ui/issues/issue-3214.rs
@@ -1,6 +1,6 @@
 fn foo<T>() {
     struct Foo {
-        x: T, //~ ERROR can't use type parameters from outer function
+        x: T, //~ ERROR can't use generic parameters from outer function
     }
 
     impl<T> Drop for Foo<T> {
diff --git a/src/test/ui/issues/issue-3214.stderr b/src/test/ui/issues/issue-3214.stderr
index 4ecea4f98006e..e6526bad3e0d3 100644
--- a/src/test/ui/issues/issue-3214.stderr
+++ b/src/test/ui/issues/issue-3214.stderr
@@ -1,13 +1,13 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-3214.rs:3:12
    |
 LL | fn foo<T>() {
    |    --- - type variable from outer function
    |    |
-   |    try adding a local type parameter in this method instead
+   |    try adding a local generic parameter in this method instead
 LL |     struct Foo {
-LL |         x: T, //~ ERROR can't use type parameters from outer function
-   |            ^ use of type variable from outer function
+LL |         x: T, //~ ERROR can't use generic parameters from outer function
+   |            ^ use of generic parameter from outer function
 
 error[E0107]: wrong number of type arguments: expected 0, found 1
   --> $DIR/issue-3214.rs:6:26
diff --git a/src/test/ui/issues/issue-32995-2.rs b/src/test/ui/issues/issue-32995-2.rs
index a4e333ec20ae0..2234f68f24629 100644
--- a/src/test/ui/issues/issue-32995-2.rs
+++ b/src/test/ui/issues/issue-32995-2.rs
@@ -2,11 +2,11 @@
 
 fn main() {
     { fn f<X: ::std::marker()::Send>() {} }
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     { fn f() -> impl ::std::marker()::Send { } }
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 }
 
@@ -14,5 +14,5 @@ fn main() {
 struct X;
 
 impl ::std::marker()::Copy for X {}
-//~^ ERROR parenthesized parameters may only be used with a trait
+//~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
 //~| WARN previously accepted
diff --git a/src/test/ui/issues/issue-32995-2.stderr b/src/test/ui/issues/issue-32995-2.stderr
index 0ac12b78d3842..104b76cba2df9 100644
--- a/src/test/ui/issues/issue-32995-2.stderr
+++ b/src/test/ui/issues/issue-32995-2.stderr
@@ -1,4 +1,4 @@
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995-2.rs:4:28
    |
 LL |     { fn f<X: ::std::marker()::Send>() {} }
@@ -8,7 +8,7 @@ LL |     { fn f<X: ::std::marker()::Send>() {} }
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995-2.rs:8:35
    |
 LL |     { fn f() -> impl ::std::marker()::Send { } }
@@ -17,7 +17,7 @@ LL |     { fn f() -> impl ::std::marker()::Send { } }
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995-2.rs:16:19
    |
 LL | impl ::std::marker()::Copy for X {}
diff --git a/src/test/ui/issues/issue-32995.rs b/src/test/ui/issues/issue-32995.rs
index 726cc85d3f479..c32fb63f1e584 100644
--- a/src/test/ui/issues/issue-32995.rs
+++ b/src/test/ui/issues/issue-32995.rs
@@ -2,32 +2,32 @@
 
 fn main() {
     let x: usize() = 1;
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     let b: ::std::boxed()::Box<_> = Box::new(1);
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     let p = ::std::str::()::from_utf8(b"foo").unwrap();
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     let p = ::std::str::from_utf8::()(b"foo").unwrap();
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     let o : Box<::std::marker()::Send> = Box::new(1);
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 
     let o : Box<Send + ::std::marker()::Sync> = Box::new(1);
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 }
 
 fn foo<X:Default>() {
     let d : X() = Default::default();
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
     //~| WARN previously accepted
 }
diff --git a/src/test/ui/issues/issue-32995.stderr b/src/test/ui/issues/issue-32995.stderr
index 12551bb7f1f00..97b4b7fa76ca8 100644
--- a/src/test/ui/issues/issue-32995.stderr
+++ b/src/test/ui/issues/issue-32995.stderr
@@ -1,4 +1,4 @@
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995.rs:4:17
    |
 LL |     let x: usize() = 1;
@@ -8,7 +8,7 @@ LL |     let x: usize() = 1;
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995.rs:8:24
    |
 LL |     let b: ::std::boxed()::Box<_> = Box::new(1);
@@ -17,25 +17,25 @@ LL |     let b: ::std::boxed()::Box<_> = Box::new(1);
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
-  --> $DIR/issue-32995.rs:12:23
+error: parenthesized type parameters may only be used with a `Fn` trait
+  --> $DIR/issue-32995.rs:12:25
    |
 LL |     let p = ::std::str::()::from_utf8(b"foo").unwrap();
-   |                       ^^^^
+   |                         ^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
-  --> $DIR/issue-32995.rs:16:34
+error: parenthesized type parameters may only be used with a `Fn` trait
+  --> $DIR/issue-32995.rs:16:36
    |
 LL |     let p = ::std::str::from_utf8::()(b"foo").unwrap();
-   |                                  ^^^^
+   |                                    ^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995.rs:20:30
    |
 LL |     let o : Box<::std::marker()::Send> = Box::new(1);
@@ -44,7 +44,7 @@ LL |     let o : Box<::std::marker()::Send> = Box::new(1);
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995.rs:24:37
    |
 LL |     let o : Box<Send + ::std::marker()::Sync> = Box::new(1);
@@ -53,7 +53,7 @@ LL |     let o : Box<Send + ::std::marker()::Sync> = Box::new(1);
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>
 
-error: parenthesized parameters may only be used with a trait
+error: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/issue-32995.rs:30:14
    |
 LL |     let d : X() = Default::default();
diff --git a/src/test/ui/issues/issue-34721.rs b/src/test/ui/issues/issue-34721.rs
new file mode 100644
index 0000000000000..226c21446b1ed
--- /dev/null
+++ b/src/test/ui/issues/issue-34721.rs
@@ -0,0 +1,34 @@
+#![feature(nll)]
+
+pub trait Foo {
+    fn zero(self) -> Self;
+}
+
+impl Foo for u32 {
+    fn zero(self) -> u32 { 0u32 }
+}
+
+pub mod bar {
+    pub use Foo;
+    pub fn bar<T: Foo>(x: T) -> T {
+      x.zero()
+    }
+}
+
+mod baz {
+    use bar;
+    use Foo;
+    pub fn baz<T: Foo>(x: T) -> T {
+        if 0 == 1 {
+            bar::bar(x.zero())
+        } else {
+            x.zero()
+        };
+        x.zero()
+        //~^ ERROR use of moved value
+    }
+}
+
+fn main() {
+    let _ = baz::baz(0u32);
+}
diff --git a/src/test/ui/issues/issue-34721.stderr b/src/test/ui/issues/issue-34721.stderr
new file mode 100644
index 0000000000000..2ed7b543e713c
--- /dev/null
+++ b/src/test/ui/issues/issue-34721.stderr
@@ -0,0 +1,20 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/issue-34721.rs:27:9
+   |
+LL |     pub fn baz<T: Foo>(x: T) -> T {
+   |                -       - move occurs because `x` has type `T`, which does not implement the `Copy` trait
+   |                |
+   |                consider adding a `Copy` constraint to this type argument
+LL |         if 0 == 1 {
+LL |             bar::bar(x.zero())
+   |                      - value moved here
+LL |         } else {
+LL |             x.zero()
+   |             - value moved here
+LL |         };
+LL |         x.zero()
+   |         ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/issues/issue-3521-2.rs b/src/test/ui/issues/issue-3521-2.rs
index 39f7fcb833756..871394f9eaeb9 100644
--- a/src/test/ui/issues/issue-3521-2.rs
+++ b/src/test/ui/issues/issue-3521-2.rs
@@ -2,7 +2,7 @@ fn main() {
     let foo = 100;
 
     static y: isize = foo + 1;
-    //~^ ERROR can't capture dynamic environment
+    //~^ ERROR attempt to use a non-constant value in a constant
 
     println!("{}", y);
 }
diff --git a/src/test/ui/issues/issue-3521-2.stderr b/src/test/ui/issues/issue-3521-2.stderr
index 1464fd74bba69..d54bbbcdc3325 100644
--- a/src/test/ui/issues/issue-3521-2.stderr
+++ b/src/test/ui/issues/issue-3521-2.stderr
@@ -1,11 +1,9 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/issue-3521-2.rs:4:23
    |
 LL |     static y: isize = foo + 1;
-   |                       ^^^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                       ^^^ non-constant value
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0434`.
+For more information about this error, try `rustc --explain E0435`.
diff --git a/src/test/ui/issues/issue-3668-2.rs b/src/test/ui/issues/issue-3668-2.rs
index 265a884ded7aa..525f6f5684e70 100644
--- a/src/test/ui/issues/issue-3668-2.rs
+++ b/src/test/ui/issues/issue-3668-2.rs
@@ -1,6 +1,6 @@
 fn f(x:isize) {
     static child: isize = x + 1;
-    //~^ ERROR can't capture dynamic environment
+    //~^ ERROR attempt to use a non-constant value in a constant
 }
 
 fn main() {}
diff --git a/src/test/ui/issues/issue-3668-2.stderr b/src/test/ui/issues/issue-3668-2.stderr
index 8dd6f49d8de5a..d6a6e8379602d 100644
--- a/src/test/ui/issues/issue-3668-2.stderr
+++ b/src/test/ui/issues/issue-3668-2.stderr
@@ -1,11 +1,9 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/issue-3668-2.rs:2:27
    |
 LL |     static child: isize = x + 1;
-   |                           ^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                           ^ non-constant value
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0434`.
+For more information about this error, try `rustc --explain E0435`.
diff --git a/src/test/ui/issues/issue-3668.rs b/src/test/ui/issues/issue-3668.rs
index 3f61b1b02e779..0e1f19a75baeb 100644
--- a/src/test/ui/issues/issue-3668.rs
+++ b/src/test/ui/issues/issue-3668.rs
@@ -6,7 +6,7 @@ trait PTrait {
 impl PTrait for P {
    fn getChildOption(&self) -> Option<Box<P>> {
        static childVal: Box<P> = self.child.get();
-       //~^ ERROR can't capture dynamic environment
+       //~^ ERROR attempt to use a non-constant value in a constant
        panic!();
    }
 }
diff --git a/src/test/ui/issues/issue-3668.stderr b/src/test/ui/issues/issue-3668.stderr
index 7f974de9da8ea..98cd3631a5365 100644
--- a/src/test/ui/issues/issue-3668.stderr
+++ b/src/test/ui/issues/issue-3668.stderr
@@ -1,11 +1,9 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/issue-3668.rs:8:34
    |
 LL |        static childVal: Box<P> = self.child.get();
-   |                                  ^^^^
-   |
-   = help: use the `|| { ... }` closure form instead
+   |                                  ^^^^ non-constant value
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0434`.
+For more information about this error, try `rustc --explain E0435`.
diff --git a/src/test/ui/issues/issue-37550.stderr b/src/test/ui/issues/issue-37550.stderr
index d2b03416cb73c..97160af43bee4 100644
--- a/src/test/ui/issues/issue-37550.stderr
+++ b/src/test/ui/issues/issue-37550.stderr
@@ -1,8 +1,11 @@
-error: function pointers in const fn are unstable
+error[E0723]: function pointers in const fn are unstable (see issue #57563)
   --> $DIR/issue-37550.rs:3:9
    |
 LL |     let x = || t; //~ ERROR function pointers in const fn are unstable
    |         ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0723`.
diff --git a/src/test/ui/issues/issue-40000.stderr b/src/test/ui/issues/issue-40000.stderr
index d7966cea52bb0..ce0c44c147563 100644
--- a/src/test/ui/issues/issue-40000.stderr
+++ b/src/test/ui/issues/issue-40000.stderr
@@ -2,10 +2,10 @@ error[E0308]: mismatched types
   --> $DIR/issue-40000.rs:6:9
    |
 LL |     foo(bar); //~ ERROR E0308
-   |         ^^^ one type is more general than the other
+   |         ^^^ expected concrete lifetime, found bound lifetime parameter
    |
-   = note: expected type `dyn for<'r> std::ops::Fn(&'r i32)`
-              found type `dyn std::ops::Fn(&i32)`
+   = note: expected type `std::boxed::Box<(dyn for<'r> std::ops::Fn(&'r i32) + 'static)>`
+              found type `std::boxed::Box<dyn std::ops::Fn(_)>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-42796.nll.stderr b/src/test/ui/issues/issue-42796.nll.stderr
index 19c6a1fd557b4..23cc88bab52d5 100644
--- a/src/test/ui/issues/issue-42796.nll.stderr
+++ b/src/test/ui/issues/issue-42796.nll.stderr
@@ -1,13 +1,13 @@
 error[E0382]: borrow of moved value: `s`
   --> $DIR/issue-42796.rs:18:20
    |
+LL |     let s = "Hello!".to_owned();
+   |         - move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let mut s_copy = s;
    |                      - value moved here
 ...
 LL |     println!("{}", s); //~ ERROR use of moved value
    |                    ^ value borrowed here after move
-   |
-   = note: move occurs because `s` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-44415.stderr b/src/test/ui/issues/issue-44415.stderr
index 441f1b2a06960..3f377fd27e7db 100644
--- a/src/test/ui/issues/issue-44415.stderr
+++ b/src/test/ui/issues/issue-44415.stderr
@@ -9,8 +9,8 @@ note: ...which requires const-evaluating `Foo::bytes::{{constant}}`...
    |
 LL |     bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires computing layout of `Foo`...
-note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
+   = note: ...which requires computing layout of `Foo`...
+   = note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
 note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}`...
   --> $DIR/issue-44415.rs:6:17
    |
diff --git a/src/test/ui/issues/issue-45829/import-twice.stderr b/src/test/ui/issues/issue-45829/import-twice.stderr
index 374b809647e7a..2a1ac57651138 100644
--- a/src/test/ui/issues/issue-45829/import-twice.stderr
+++ b/src/test/ui/issues/issue-45829/import-twice.stderr
@@ -2,15 +2,13 @@ error[E0252]: the name `A` is defined multiple times
   --> $DIR/import-twice.rs:6:14
    |
 LL | use foo::{A, A};
-   |           -  ^ `A` reimported here
-   |           |
+   |           ---^
+   |           || |
+   |           || `A` reimported here
+   |           |help: remove unnecessary import
    |           previous import of the type `A` here
    |
    = note: `A` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use foo::{A, A as OtherA};
-   |              ^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-48636.fixed b/src/test/ui/issues/issue-48636.fixed
index 39e6c98b1f5b9..87c19a32d4c01 100644
--- a/src/test/ui/issues/issue-48636.fixed
+++ b/src/test/ui/issues/issue-48636.fixed
@@ -4,8 +4,9 @@
 
 struct S {
     x: u8,
-    /// The id of the parent core
+    /// The ID of the parent core
     y: u8,
 }
 //~^^^ ERROR found a documentation comment that doesn't document anything
+
 fn main() {}
diff --git a/src/test/ui/issues/issue-48636.rs b/src/test/ui/issues/issue-48636.rs
index bcf57772b515f..8610dc2f72ecf 100644
--- a/src/test/ui/issues/issue-48636.rs
+++ b/src/test/ui/issues/issue-48636.rs
@@ -4,8 +4,9 @@
 
 struct S {
     x: u8
-    /// The id of the parent core
+    /// The ID of the parent core
     y: u8,
 }
 //~^^^ ERROR found a documentation comment that doesn't document anything
+
 fn main() {}
diff --git a/src/test/ui/issues/issue-48636.stderr b/src/test/ui/issues/issue-48636.stderr
index de335d2c29b18..462723d1d931e 100644
--- a/src/test/ui/issues/issue-48636.stderr
+++ b/src/test/ui/issues/issue-48636.stderr
@@ -3,7 +3,7 @@ error[E0585]: found a documentation comment that doesn't document anything
    |
 LL |     x: u8
    |          - help: missing comma here: `,`
-LL |     /// The id of the parent core
+LL |     /// The ID of the parent core
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: doc comments must come before what they document, maybe a comment was intended with `//`?
diff --git a/src/test/ui/issues/issue-49074.stderr b/src/test/ui/issues/issue-49074.stderr
index d4648270f2d30..a25d8ee352686 100644
--- a/src/test/ui/issues/issue-49074.stderr
+++ b/src/test/ui/issues/issue-49074.stderr
@@ -2,7 +2,7 @@ error[E0658]: The attribute `marco_use` is currently unknown to the compiler and
   --> $DIR/issue-49074.rs:3:3
    |
 LL | #[marco_use] // typo
-   |   ^^^^^^^^^
+   |   ^^^^^^^^^ help: a built-in attribute with a similar name exists: `macro_use`
    |
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
 
diff --git a/src/test/ui/issues/issue-49934.rs b/src/test/ui/issues/issue-49934.rs
index 59ca6cc292db9..ad410f30c04d4 100644
--- a/src/test/ui/issues/issue-49934.rs
+++ b/src/test/ui/issues/issue-49934.rs
@@ -30,12 +30,12 @@ fn main() {
     #[derive(Debug)] //~ WARN unused attribute
     let _ = "Hello, world!";
 
-    // fold_expr
+    // visit_expr
     let _ = #[derive(Debug)] "Hello, world!";
     //~^ WARN unused attribute
 
     let _ = [
-        // fold_opt_expr
+        // filter_map_expr
         #[derive(Debug)] //~ WARN unused attribute
         "Hello, world!"
     ];
diff --git a/src/test/ui/issues/issue-50264-inner-deref-trait/result-deref-err.stderr b/src/test/ui/issues/issue-50264-inner-deref-trait/result-deref-err.stderr
index 99c4a5b03b320..96d6814b0fe93 100644
--- a/src/test/ui/issues/issue-50264-inner-deref-trait/result-deref-err.stderr
+++ b/src/test/ui/issues/issue-50264-inner-deref-trait/result-deref-err.stderr
@@ -2,11 +2,10 @@ error[E0599]: no method named `deref_err` found for type `std::result::Result<_,
   --> $DIR/result-deref-err.rs:4:28
    |
 LL |     let _result = &Err(41).deref_err();
-   |                            ^^^^^^^^^
+   |                            ^^^^^^^^^ help: did you mean: `deref_ok`
    |
    = note: the method `deref_err` exists but the following trait bounds were not satisfied:
            `{integer} : std::ops::Deref`
-   = help: did you mean `deref_ok`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-5067.rs b/src/test/ui/issues/issue-5067.rs
index 526a68311462e..616fd09907a2b 100644
--- a/src/test/ui/issues/issue-5067.rs
+++ b/src/test/ui/issues/issue-5067.rs
@@ -1,37 +1,59 @@
 #![allow(unused_macros)]
 
+// Tests that repetition matchers cannot match the empty token tree (since that would be
+// ambiguous).
+
+// edition:2018
+
 macro_rules! foo {
     ( $()* ) => {};
     //~^ ERROR repetition matches empty token tree
     ( $()+ ) => {};
     //~^ ERROR repetition matches empty token tree
-
+    ( $()? ) => {};
+    //~^ ERROR repetition matches empty token tree
     ( $(),* ) => {}; // PASS
     ( $(),+ ) => {}; // PASS
-
+    // `?` cannot have a separator...
     ( [$()*] ) => {};
     //~^ ERROR repetition matches empty token tree
     ( [$()+] ) => {};
     //~^ ERROR repetition matches empty token tree
-
+    ( [$()?] ) => {};
+    //~^ ERROR repetition matches empty token tree
     ( [$(),*] ) => {}; // PASS
     ( [$(),+] ) => {}; // PASS
-
+    // `?` cannot have a separator...
     ( $($()* $(),* $(a)* $(a),* )* ) => {};
     //~^ ERROR repetition matches empty token tree
     ( $($()* $(),* $(a)* $(a),* )+ ) => {};
     //~^ ERROR repetition matches empty token tree
-
+    ( $($()* $(),* $(a)* $(a),* )? ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $($()? $(),* $(a)? $(a),* )* ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $($()? $(),* $(a)? $(a),* )+ ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $($()? $(),* $(a)? $(a),* )? ) => {};
+    //~^ ERROR repetition matches empty token tree
     ( $(a     $(),* $(a)* $(a),* )* ) => {}; // PASS
     ( $($(a)+ $(),* $(a)* $(a),* )+ ) => {}; // PASS
+    ( $($(a)+ $(),* $(a)* $(a),* )? ) => {}; // PASS
+
+    ( $(a     $(),* $(a)? $(a),* )* ) => {}; // PASS
+    ( $($(a)+ $(),* $(a)? $(a),* )+ ) => {}; // PASS
+    ( $($(a)+ $(),* $(a)? $(a),* )? ) => {}; // PASS
 
     ( $(a $()+)* ) => {};
     //~^ ERROR repetition matches empty token tree
     ( $(a $()*)+ ) => {};
     //~^ ERROR repetition matches empty token tree
+    ( $(a $()+)? ) => {};
+    //~^ ERROR repetition matches empty token tree
+    ( $(a $()?)+ ) => {};
+    //~^ ERROR repetition matches empty token tree
 }
 
-
 // --- Original Issue --- //
 
 macro_rules! make_vec {
@@ -43,11 +65,10 @@ fn main() {
     let _ = make_vec![a 1, a 2, a 3];
 }
 
-
 // --- Minified Issue --- //
 
 macro_rules! m {
-    ( $()* ) => {}
+    ( $()* ) => {};
     //~^ ERROR repetition matches empty token tree
 }
 
diff --git a/src/test/ui/issues/issue-5067.stderr b/src/test/ui/issues/issue-5067.stderr
index 433b7c8c04907..7ffc6071407c5 100644
--- a/src/test/ui/issues/issue-5067.stderr
+++ b/src/test/ui/issues/issue-5067.stderr
@@ -1,62 +1,110 @@
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:4:8
+  --> $DIR/issue-5067.rs:9:8
    |
 LL |     ( $()* ) => {};
    |        ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:6:8
+  --> $DIR/issue-5067.rs:11:8
    |
 LL |     ( $()+ ) => {};
    |        ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:12:9
+  --> $DIR/issue-5067.rs:13:8
+   |
+LL |     ( $()? ) => {};
+   |        ^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:18:9
    |
 LL |     ( [$()*] ) => {};
    |         ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:14:9
+  --> $DIR/issue-5067.rs:20:9
    |
 LL |     ( [$()+] ) => {};
    |         ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:20:8
+  --> $DIR/issue-5067.rs:22:9
+   |
+LL |     ( [$()?] ) => {};
+   |         ^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:27:8
    |
 LL |     ( $($()* $(),* $(a)* $(a),* )* ) => {};
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:22:8
+  --> $DIR/issue-5067.rs:29:8
    |
 LL |     ( $($()* $(),* $(a)* $(a),* )+ ) => {};
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:28:12
+  --> $DIR/issue-5067.rs:31:8
+   |
+LL |     ( $($()* $(),* $(a)* $(a),* )? ) => {};
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:33:8
+   |
+LL |     ( $($()? $(),* $(a)? $(a),* )* ) => {};
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:35:8
+   |
+LL |     ( $($()? $(),* $(a)? $(a),* )+ ) => {};
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:37:8
+   |
+LL |     ( $($()? $(),* $(a)? $(a),* )? ) => {};
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:47:12
    |
 LL |     ( $(a $()+)* ) => {};
    |            ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:30:12
+  --> $DIR/issue-5067.rs:49:12
    |
 LL |     ( $(a $()*)+ ) => {};
    |            ^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:38:18
+  --> $DIR/issue-5067.rs:51:12
+   |
+LL |     ( $(a $()+)? ) => {};
+   |            ^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:53:12
+   |
+LL |     ( $(a $()?)+ ) => {};
+   |            ^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-5067.rs:60:18
    |
 LL |     (a $e1:expr $($(, a $e2:expr)*)*) => ([$e1 $($(, $e2)*)*]);
    |                  ^^^^^^^^^^^^^^^^^^
 
 error: repetition matches empty token tree
-  --> $DIR/issue-5067.rs:50:8
+  --> $DIR/issue-5067.rs:71:8
    |
-LL |     ( $()* ) => {}
+LL |     ( $()* ) => {};
    |        ^^
 
-error: aborting due to 10 previous errors
+error: aborting due to 18 previous errors
 
diff --git a/src/test/ui/issues/issue-52126-assign-op-invariance.nll.stderr b/src/test/ui/issues/issue-52126-assign-op-invariance.nll.stderr
index 8332cf1b3a30c..d231f621e59c7 100644
--- a/src/test/ui/issues/issue-52126-assign-op-invariance.nll.stderr
+++ b/src/test/ui/issues/issue-52126-assign-op-invariance.nll.stderr
@@ -5,7 +5,7 @@ LL |         let v: Vec<&str> = line.split_whitespace().collect();
    |                            ^^^^ borrowed value does not live long enough
 ...
 LL |         acc += cnt2;
-   |         --- borrow used here, in later iteration of loop
+   |         --- borrow later used here
 ...
 LL |     }
    |     - `line` dropped here while still borrowed
diff --git a/src/test/ui/issues/issue-52126-assign-op-invariance.rs b/src/test/ui/issues/issue-52126-assign-op-invariance.rs
index b974a8d4bdafb..c96cfdf3cd164 100644
--- a/src/test/ui/issues/issue-52126-assign-op-invariance.rs
+++ b/src/test/ui/issues/issue-52126-assign-op-invariance.rs
@@ -27,7 +27,7 @@ impl<'l> AddAssign for Counter<'l>
     }
 }
 
-/// often times crashes, if not prints invalid strings
+/// Often crashes, if not prints invalid strings.
 pub fn panics() {
     let mut acc = Counter{map: HashMap::new()};
     for line in vec!["123456789".to_string(), "12345678".to_string()] {
diff --git a/src/test/ui/issues/issue-52496.rs b/src/test/ui/issues/issue-52496.rs
new file mode 100644
index 0000000000000..4e9453653735a
--- /dev/null
+++ b/src/test/ui/issues/issue-52496.rs
@@ -0,0 +1,12 @@
+struct Foo { bar: f64, baz: i64, bat: i64 }
+
+fn main() {
+    let _ = Foo { bar: .5, baz: 42 };
+    //~^ ERROR float literals must have an integer part
+    //~| ERROR missing field `bat` in initializer of `Foo`
+    let bar = 1.5f32;
+    let _ = Foo { bar.into(), bat: -1, . };
+    //~^ ERROR expected one of
+    //~| ERROR missing fields `bar`, `baz` in initializer of `Foo`
+    //~| ERROR expected identifier, found `.`
+}
diff --git a/src/test/ui/issues/issue-52496.stderr b/src/test/ui/issues/issue-52496.stderr
new file mode 100644
index 0000000000000..43009a15bd49a
--- /dev/null
+++ b/src/test/ui/issues/issue-52496.stderr
@@ -0,0 +1,37 @@
+error: float literals must have an integer part
+  --> $DIR/issue-52496.rs:4:24
+   |
+LL |     let _ = Foo { bar: .5, baz: 42 };
+   |                        ^^ help: must have an integer part: `0.5`
+
+error: expected one of `,` or `}`, found `.`
+  --> $DIR/issue-52496.rs:8:22
+   |
+LL |     let _ = Foo { bar.into(), bat: -1, . };
+   |             ---      ^ expected one of `,` or `}` here
+   |             |
+   |             while parsing this struct
+
+error: expected identifier, found `.`
+  --> $DIR/issue-52496.rs:8:40
+   |
+LL |     let _ = Foo { bar.into(), bat: -1, . };
+   |             ---                        ^ expected identifier
+   |             |
+   |             while parsing this struct
+
+error[E0063]: missing field `bat` in initializer of `Foo`
+  --> $DIR/issue-52496.rs:4:13
+   |
+LL |     let _ = Foo { bar: .5, baz: 42 };
+   |             ^^^ missing `bat`
+
+error[E0063]: missing fields `bar`, `baz` in initializer of `Foo`
+  --> $DIR/issue-52496.rs:8:13
+   |
+LL |     let _ = Foo { bar.into(), bat: -1, . };
+   |             ^^^ missing `bar`, `baz`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0063`.
diff --git a/src/test/ui/issues/issue-52891.fixed b/src/test/ui/issues/issue-52891.fixed
new file mode 100644
index 0000000000000..e694b5c9b154f
--- /dev/null
+++ b/src/test/ui/issues/issue-52891.fixed
@@ -0,0 +1,37 @@
+// aux-build:issue-52891.rs
+// run-rustfix
+
+#![allow(warnings)]
+
+extern crate issue_52891;
+
+// Check that we don't suggest renaming duplicate imports but instead
+// suggest removing one.
+
+use issue_52891::a;
+ //~ ERROR `a` is defined multiple times
+
+use issue_52891::{b, c}; //~ ERROR `a` is defined multiple times
+use issue_52891::{d, e}; //~ ERROR `a` is defined multiple times
+use issue_52891::{f, g}; //~ ERROR `a` is defined multiple times
+
+use issue_52891::{//~ ERROR `a` is defined multiple times
+    h,
+    i};
+use issue_52891::{j,
+    //~ ERROR `a` is defined multiple times
+    k};
+use issue_52891::{l,
+    m}; //~ ERROR `a` is defined multiple times
+
+use issue_52891::a::inner;
+use issue_52891::b::inner as other_inner; //~ ERROR `inner` is defined multiple times
+
+
+//~^ ERROR `issue_52891` is defined multiple times
+
+
+#[macro_use]
+use issue_52891::n; //~ ERROR `n` is defined multiple times
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-52891.rs b/src/test/ui/issues/issue-52891.rs
new file mode 100644
index 0000000000000..cd4b40629ab7f
--- /dev/null
+++ b/src/test/ui/issues/issue-52891.rs
@@ -0,0 +1,38 @@
+// aux-build:issue-52891.rs
+// run-rustfix
+
+#![allow(warnings)]
+
+extern crate issue_52891;
+
+// Check that we don't suggest renaming duplicate imports but instead
+// suggest removing one.
+
+use issue_52891::a;
+use issue_52891::a; //~ ERROR `a` is defined multiple times
+
+use issue_52891::{a, b, c}; //~ ERROR `a` is defined multiple times
+use issue_52891::{d, a, e}; //~ ERROR `a` is defined multiple times
+use issue_52891::{f, g, a}; //~ ERROR `a` is defined multiple times
+
+use issue_52891::{a, //~ ERROR `a` is defined multiple times
+    h,
+    i};
+use issue_52891::{j,
+    a, //~ ERROR `a` is defined multiple times
+    k};
+use issue_52891::{l,
+    m,
+    a}; //~ ERROR `a` is defined multiple times
+
+use issue_52891::a::inner;
+use issue_52891::b::inner; //~ ERROR `inner` is defined multiple times
+
+use issue_52891::{self};
+//~^ ERROR `issue_52891` is defined multiple times
+
+use issue_52891::n;
+#[macro_use]
+use issue_52891::n; //~ ERROR `n` is defined multiple times
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-52891.stderr b/src/test/ui/issues/issue-52891.stderr
new file mode 100644
index 0000000000000..65b2b9460bc94
--- /dev/null
+++ b/src/test/ui/issues/issue-52891.stderr
@@ -0,0 +1,145 @@
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:12:5
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+LL | use issue_52891::a; //~ ERROR `a` is defined multiple times
+   | ----^^^^^^^^^^^^^^-
+   | |   |
+   | |   `a` reimported here
+   | help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:14:19
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+...
+LL | use issue_52891::{a, b, c}; //~ ERROR `a` is defined multiple times
+   |                   ^--
+   |                   |
+   |                   `a` reimported here
+   |                   help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:15:22
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+...
+LL | use issue_52891::{d, a, e}; //~ ERROR `a` is defined multiple times
+   |                      ^--
+   |                      |
+   |                      `a` reimported here
+   |                      help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:16:25
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+...
+LL | use issue_52891::{f, g, a}; //~ ERROR `a` is defined multiple times
+   |                       --^
+   |                       | |
+   |                       | `a` reimported here
+   |                       help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:18:19
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+...
+LL | use issue_52891::{a, //~ ERROR `a` is defined multiple times
+   |                   ^--
+   |                   |
+   |                   `a` reimported here
+   |                   help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:22:5
+   |
+LL | use issue_52891::a;
+   |     -------------- previous import of the module `a` here
+...
+LL |     a, //~ ERROR `a` is defined multiple times
+   |     ^--
+   |     |
+   |     `a` reimported here
+   |     help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `a` is defined multiple times
+  --> $DIR/issue-52891.rs:26:5
+   |
+LL |   use issue_52891::a;
+   |       -------------- previous import of the module `a` here
+...
+LL |       m,
+   |  ______-
+LL | |     a}; //~ ERROR `a` is defined multiple times
+   | |     ^
+   | |     |
+   | |_____`a` reimported here
+   |       help: remove unnecessary import
+   |
+   = note: `a` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `inner` is defined multiple times
+  --> $DIR/issue-52891.rs:29:5
+   |
+LL | use issue_52891::a::inner;
+   |     --------------------- previous import of the module `inner` here
+LL | use issue_52891::b::inner; //~ ERROR `inner` is defined multiple times
+   |     ^^^^^^^^^^^^^^^^^^^^^ `inner` reimported here
+   |
+   = note: `inner` must be defined only once in the type namespace of this module
+help: you can use `as` to change the binding name of the import
+   |
+LL | use issue_52891::b::inner as other_inner; //~ ERROR `inner` is defined multiple times
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0254]: the name `issue_52891` is defined multiple times
+  --> $DIR/issue-52891.rs:31:19
+   |
+LL | extern crate issue_52891;
+   | ------------------------- previous import of the extern crate `issue_52891` here
+...
+LL | use issue_52891::{self};
+   | ------------------^^^^--
+   | |                 |
+   | |                 `issue_52891` reimported here
+   | help: remove unnecessary import
+   |
+   = note: `issue_52891` must be defined only once in the type namespace of this module
+
+error[E0252]: the name `n` is defined multiple times
+  --> $DIR/issue-52891.rs:36:5
+   |
+LL | use issue_52891::n;
+   | -------------------
+   | |   |
+   | |   previous import of the module `n` here
+   | help: remove unnecessary import
+LL | #[macro_use]
+LL | use issue_52891::n; //~ ERROR `n` is defined multiple times
+   |     ^^^^^^^^^^^^^^ `n` reimported here
+   |
+   = note: `n` must be defined only once in the type namespace of this module
+
+error: aborting due to 10 previous errors
+
+Some errors occurred: E0252, E0254.
+For more information about an error, try `rustc --explain E0252`.
diff --git a/src/test/ui/issues/issue-54302-cases.stderr b/src/test/ui/issues/issue-54302-cases.stderr
index c1329d331a181..98637611b79fe 100644
--- a/src/test/ui/issues/issue-54302-cases.stderr
+++ b/src/test/ui/issues/issue-54302-cases.stderr
@@ -4,8 +4,8 @@ error: implementation of `Foo` is not general enough
 LL |     <u32 as RefFoo<u32>>::ref_foo(a)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'0 u32` must implement `Foo<'static, u32>` for any lifetime `'0`
-   = note: but `&'1 _` only implements `Foo<'_, _>` for the lifetime `'1`
+   = note: `Foo<'static, u32>` would have to be implemented for the type `&'0 u32`, for any lifetime `'0`
+   = note: but `Foo<'_, u32>` is actually implemented for the type `&'1 u32`, for some specific lifetime `'1`
 
 error: implementation of `Foo` is not general enough
   --> $DIR/issue-54302-cases.rs:69:5
@@ -13,8 +13,8 @@ error: implementation of `Foo` is not general enough
 LL |     <i32 as RefFoo<i32>>::ref_foo(a)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'0 i32` must implement `Foo<'static, i32>` for any lifetime `'0`
-   = note: but `&'1 _` only implements `Foo<'_, _>` for the lifetime `'1`
+   = note: `Foo<'static, i32>` would have to be implemented for the type `&'0 i32`, for any lifetime `'0`
+   = note: but `Foo<'_, i32>` is actually implemented for the type `&'1 i32`, for some specific lifetime `'1`
 
 error: implementation of `Foo` is not general enough
   --> $DIR/issue-54302-cases.rs:75:5
@@ -22,8 +22,8 @@ error: implementation of `Foo` is not general enough
 LL |     <u64 as RefFoo<u64>>::ref_foo(a)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'0 u64` must implement `Foo<'static, u64>` for any lifetime `'0`
-   = note: but `&'1 _` only implements `Foo<'_, _>` for the lifetime `'1`
+   = note: `Foo<'static, u64>` would have to be implemented for the type `&'0 u64`, for any lifetime `'0`
+   = note: but `Foo<'_, u64>` is actually implemented for the type `&'1 u64`, for some specific lifetime `'1`
 
 error: implementation of `Foo` is not general enough
   --> $DIR/issue-54302-cases.rs:81:5
@@ -31,8 +31,8 @@ error: implementation of `Foo` is not general enough
 LL |     <i64 as RefFoo<i64>>::ref_foo(a)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'0 i64` must implement `Foo<'static, i64>` for any lifetime `'0`
-   = note: but `&'1 _` only implements `Foo<'_, _>` for the lifetime `'1`
+   = note: `Foo<'static, i64>` would have to be implemented for the type `&'0 i64`, for any lifetime `'0`
+   = note: but `Foo<'_, i64>` is actually implemented for the type `&'1 i64`, for some specific lifetime `'1`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/issues/issue-54302.stderr b/src/test/ui/issues/issue-54302.stderr
index 1b255204b6ef7..c6d0805f3ab2a 100644
--- a/src/test/ui/issues/issue-54302.stderr
+++ b/src/test/ui/issues/issue-54302.stderr
@@ -4,8 +4,8 @@ error: implementation of `Deserialize` is not general enough
 LL |     assert_deserialize_owned::<&'static str>();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `&'static str` must implement `Deserialize<'0>` for any lifetime `'0`
-   = note: but `&str` only implements `Deserialize<'1>` for some lifetime `'1`
+   = note: `&'static str` must implement `Deserialize<'0>`, for any lifetime `'0`
+   = note: but `&str` actually implements `Deserialize<'1>`, for some specific lifetime `'1`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-54521-1.rs b/src/test/ui/issues/issue-54521-1.rs
new file mode 100644
index 0000000000000..d6a14a6e11f67
--- /dev/null
+++ b/src/test/ui/issues/issue-54521-1.rs
@@ -0,0 +1,16 @@
+// compile-pass
+
+// This test checks that the `remove extra angle brackets` error doesn't happen for some
+// potential edge-cases..
+
+struct X {
+    len: u32,
+}
+
+fn main() {
+    let x = X { len: 3 };
+
+    let _ = x.len > (3);
+
+    let _ = x.len >> (3);
+}
diff --git a/src/test/ui/issues/issue-54521-2.fixed b/src/test/ui/issues/issue-54521-2.fixed
new file mode 100644
index 0000000000000..a91c4fe43ea46
--- /dev/null
+++ b/src/test/ui/issues/issue-54521-2.fixed
@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = Vec::<usize>>>::new();
+//                     ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = Vec::<usize>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>::new();
+    //~^ ERROR unmatched angle bracket
+}
diff --git a/src/test/ui/issues/issue-54521-2.rs b/src/test/ui/issues/issue-54521-2.rs
new file mode 100644
index 0000000000000..3639aac87ee7f
--- /dev/null
+++ b/src/test/ui/issues/issue-54521-2.rs
@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = Vec::<usize>>>::new();
+//                     ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = Vec::<usize>>>>>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>>>>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>>>::new();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = Vec::<usize>>::new();
+    //~^ ERROR unmatched angle bracket
+}
diff --git a/src/test/ui/issues/issue-54521-2.stderr b/src/test/ui/issues/issue-54521-2.stderr
new file mode 100644
index 0000000000000..9556b83b730a4
--- /dev/null
+++ b/src/test/ui/issues/issue-54521-2.stderr
@@ -0,0 +1,26 @@
+error: unmatched angle brackets
+  --> $DIR/issue-54521-2.rs:11:25
+   |
+LL |     let _ = Vec::<usize>>>>>::new();
+   |                         ^^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-54521-2.rs:14:25
+   |
+LL |     let _ = Vec::<usize>>>>::new();
+   |                         ^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-54521-2.rs:17:25
+   |
+LL |     let _ = Vec::<usize>>>::new();
+   |                         ^^ help: remove extra angle brackets
+
+error: unmatched angle bracket
+  --> $DIR/issue-54521-2.rs:20:25
+   |
+LL |     let _ = Vec::<usize>>::new();
+   |                         ^ help: remove extra angle bracket
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/issues/issue-54521.fixed b/src/test/ui/issues/issue-54521.fixed
new file mode 100644
index 0000000000000..84ab6866cf133
--- /dev/null
+++ b/src/test/ui/issues/issue-54521.fixed
@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+//                                                        ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+}
diff --git a/src/test/ui/issues/issue-54521.rs b/src/test/ui/issues/issue-54521.rs
new file mode 100644
index 0000000000000..f1d6850417880
--- /dev/null
+++ b/src/test/ui/issues/issue-54521.rs
@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+//                                                        ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>();
+    //~^ ERROR unmatched angle bracket
+}
diff --git a/src/test/ui/issues/issue-54521.stderr b/src/test/ui/issues/issue-54521.stderr
new file mode 100644
index 0000000000000..ffefbfd0348a8
--- /dev/null
+++ b/src/test/ui/issues/issue-54521.stderr
@@ -0,0 +1,26 @@
+error: unmatched angle brackets
+  --> $DIR/issue-54521.rs:11:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>>();
+   |                                                            ^^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-54521.rs:14:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>();
+   |                                                            ^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-54521.rs:17:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+   |                                                            ^^ help: remove extra angle brackets
+
+error: unmatched angle bracket
+  --> $DIR/issue-54521.rs:20:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>();
+   |                                                            ^ help: remove extra angle bracket
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/issues/issue-54582.rs b/src/test/ui/issues/issue-54582.rs
new file mode 100644
index 0000000000000..c2dbf361911b5
--- /dev/null
+++ b/src/test/ui/issues/issue-54582.rs
@@ -0,0 +1,16 @@
+// run-pass
+
+pub trait Stage: Sync {}
+
+pub enum Enum {
+    A,
+    B,
+}
+
+impl Stage for Enum {}
+
+pub static ARRAY: [(&Stage, &str); 1] = [
+    (&Enum::A, ""),
+];
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-56411.rs b/src/test/ui/issues/issue-56411.rs
new file mode 100644
index 0000000000000..3561c21cc7ee3
--- /dev/null
+++ b/src/test/ui/issues/issue-56411.rs
@@ -0,0 +1,17 @@
+macro_rules! import {
+    ( $($name:ident),* ) => {
+        $(
+            mod $name;
+            pub use self::$name;
+            //~^ ERROR the name `issue_56411_aux` is defined multiple times
+            //~| ERROR `issue_56411_aux` is private, and cannot be re-exported
+
+        )*
+    }
+}
+
+import!(issue_56411_aux);
+
+fn main() {
+    println!("Hello, world!");
+}
diff --git a/src/test/ui/issues/issue-56411.stderr b/src/test/ui/issues/issue-56411.stderr
new file mode 100644
index 0000000000000..dd05852c09159
--- /dev/null
+++ b/src/test/ui/issues/issue-56411.stderr
@@ -0,0 +1,31 @@
+error[E0255]: the name `issue_56411_aux` is defined multiple times
+  --> $DIR/issue-56411.rs:5:21
+   |
+LL |             mod $name;
+   |             ---------- previous definition of the module `issue_56411_aux` here
+LL |             pub use self::$name;
+   |                     ^^^^^^^^^^^
+   |                     |
+   |                     `issue_56411_aux` reimported here
+   |                     you can use `as` to change the binding name of the import
+...
+LL | import!(issue_56411_aux);
+   | ------------------------- in this macro invocation
+   |
+   = note: `issue_56411_aux` must be defined only once in the type namespace of this module
+
+error[E0365]: `issue_56411_aux` is private, and cannot be re-exported
+  --> $DIR/issue-56411.rs:5:21
+   |
+LL |             pub use self::$name;
+   |                     ^^^^^^^^^^^ re-export of private `issue_56411_aux`
+...
+LL | import!(issue_56411_aux);
+   | ------------------------- in this macro invocation
+   |
+   = note: consider declaring type or module `issue_56411_aux` with `pub`
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0255, E0365.
+For more information about an error, try `rustc --explain E0255`.
diff --git a/src/test/ui/issues/issue-56488.rs b/src/test/ui/issues/issue-56488.rs
new file mode 100644
index 0000000000000..e2f3996927b7f
--- /dev/null
+++ b/src/test/ui/issues/issue-56488.rs
@@ -0,0 +1,13 @@
+// run-pass
+
+#![feature(trait_alias)]
+
+mod alpha {
+    pub trait A {}
+    pub trait C = A;
+}
+
+#[allow(unused_imports)]
+use alpha::C;
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-56685.rs b/src/test/ui/issues/issue-56685.rs
new file mode 100644
index 0000000000000..f320c99ed15d1
--- /dev/null
+++ b/src/test/ui/issues/issue-56685.rs
@@ -0,0 +1,44 @@
+#![allow(dead_code)]
+#![deny(unused_variables)]
+
+// This test aims to check that unused variable suggestions update bindings in all
+// match arms.
+
+fn main() {
+    enum E {
+        A(i32,),
+        B(i32,),
+    }
+
+    match E::A(1) {
+        E::A(x) | E::B(x) => {}
+        //~^ ERROR unused variable: `x`
+    }
+
+    enum F {
+        A(i32, i32,),
+        B(i32, i32,),
+        C(i32, i32,),
+    }
+
+    let _ = match F::A(1, 2) {
+        F::A(x, y) | F::B(x, y) => { y },
+        //~^ ERROR unused variable: `x`
+        F::C(a, b) => { 3 }
+        //~^ ERROR unused variable: `a`
+        //~^^ ERROR unused variable: `b`
+    };
+
+    let _ = if let F::A(x, y) | F::B(x, y) = F::A(1, 2) {
+    //~^ ERROR unused variable: `x`
+        y
+    } else {
+        3
+    };
+
+    while let F::A(x, y) | F::B(x, y) = F::A(1, 2) {
+    //~^ ERROR unused variable: `x`
+        let _ = y;
+        break;
+    }
+}
diff --git a/src/test/ui/issues/issue-56685.stderr b/src/test/ui/issues/issue-56685.stderr
new file mode 100644
index 0000000000000..4a461c72b2417
--- /dev/null
+++ b/src/test/ui/issues/issue-56685.stderr
@@ -0,0 +1,60 @@
+error: unused variable: `x`
+  --> $DIR/issue-56685.rs:14:14
+   |
+LL |         E::A(x) | E::B(x) => {}
+   |              ^         ^
+   |
+note: lint level defined here
+  --> $DIR/issue-56685.rs:2:9
+   |
+LL | #![deny(unused_variables)]
+   |         ^^^^^^^^^^^^^^^^
+help: consider prefixing with an underscore
+   |
+LL |         E::A(_x) | E::B(_x) => {}
+   |              ^^         ^^
+
+error: unused variable: `x`
+  --> $DIR/issue-56685.rs:25:14
+   |
+LL |         F::A(x, y) | F::B(x, y) => { y },
+   |              ^            ^
+help: consider prefixing with an underscore
+   |
+LL |         F::A(_x, y) | F::B(_x, y) => { y },
+   |              ^^            ^^
+
+error: unused variable: `a`
+  --> $DIR/issue-56685.rs:27:14
+   |
+LL |         F::C(a, b) => { 3 }
+   |              ^ help: consider prefixing with an underscore: `_a`
+
+error: unused variable: `b`
+  --> $DIR/issue-56685.rs:27:17
+   |
+LL |         F::C(a, b) => { 3 }
+   |                 ^ help: consider prefixing with an underscore: `_b`
+
+error: unused variable: `x`
+  --> $DIR/issue-56685.rs:32:25
+   |
+LL |     let _ = if let F::A(x, y) | F::B(x, y) = F::A(1, 2) {
+   |                         ^            ^
+help: consider prefixing with an underscore
+   |
+LL |     let _ = if let F::A(_x, y) | F::B(_x, y) = F::A(1, 2) {
+   |                         ^^            ^^
+
+error: unused variable: `x`
+  --> $DIR/issue-56685.rs:39:20
+   |
+LL |     while let F::A(x, y) | F::B(x, y) = F::A(1, 2) {
+   |                    ^            ^
+help: consider prefixing with an underscore
+   |
+LL |     while let F::A(_x, y) | F::B(_x, y) = F::A(1, 2) {
+   |                    ^^            ^^
+
+error: aborting due to 6 previous errors
+
diff --git a/src/test/ui/issues/issue-56943.rs b/src/test/ui/issues/issue-56943.rs
new file mode 100644
index 0000000000000..8fc77abdbf588
--- /dev/null
+++ b/src/test/ui/issues/issue-56943.rs
@@ -0,0 +1,8 @@
+// aux-build:issue-56943.rs
+
+extern crate issue_56943;
+
+fn main() {
+    let _: issue_56943::S = issue_56943::S2;
+    //~^ ERROR mismatched types [E0308]
+}
diff --git a/src/test/ui/issues/issue-56943.stderr b/src/test/ui/issues/issue-56943.stderr
new file mode 100644
index 0000000000000..27202051524c9
--- /dev/null
+++ b/src/test/ui/issues/issue-56943.stderr
@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-56943.rs:6:29
+   |
+LL |     let _: issue_56943::S = issue_56943::S2;
+   |                             ^^^^^^^^^^^^^^^ expected struct `issue_56943::S`, found struct `issue_56943::S2`
+   |
+   = note: expected type `issue_56943::S`
+              found type `issue_56943::S2`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/issues/issue-57362-1.rs b/src/test/ui/issues/issue-57362-1.rs
new file mode 100644
index 0000000000000..1fa417fe98ab7
--- /dev/null
+++ b/src/test/ui/issues/issue-57362-1.rs
@@ -0,0 +1,23 @@
+// Test for issue #57362, ensuring that the self ty is shown in cases of higher-ranked lifetimes
+// conflicts: the `expected` and `found` trait refs would otherwise be printed the same, leading
+// to confusing notes such as:
+//  = note: expected type `Trait`
+//             found type `Trait`
+
+// from issue #57362
+trait Trait {
+    fn f(self);
+}
+
+impl<T> Trait for fn(&T) {
+    fn f(self) {
+        println!("f");
+    }
+}
+
+fn f() {
+    let a: fn(_) = |_: &u8| {};
+    a.f(); //~ ERROR no method named `f`
+}
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-57362-1.stderr b/src/test/ui/issues/issue-57362-1.stderr
new file mode 100644
index 0000000000000..b21b35849b172
--- /dev/null
+++ b/src/test/ui/issues/issue-57362-1.stderr
@@ -0,0 +1,14 @@
+error[E0599]: no method named `f` found for type `fn(&u8)` in the current scope
+  --> $DIR/issue-57362-1.rs:20:7
+   |
+LL |     a.f(); //~ ERROR no method named `f`
+   |       ^
+   |
+   = note: a is a function, perhaps you wish to call it
+   = help: items from traits can only be used if the trait is implemented and in scope
+   = note: the following trait defines an item `f`, perhaps you need to implement it:
+           candidate #1: `Trait`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/issues/issue-57362-2.rs b/src/test/ui/issues/issue-57362-2.rs
new file mode 100644
index 0000000000000..870d7f28ba953
--- /dev/null
+++ b/src/test/ui/issues/issue-57362-2.rs
@@ -0,0 +1,25 @@
+// Test for issue #57362, ensuring that the self ty is shown in cases of higher-ranked lifetimes
+// conflicts: the `expected` and `found` trait refs would otherwise be printed the same, leading
+// to confusing notes such as:
+//  = note: expected type `Trait`
+//             found type `Trait`
+
+// extracted from a similar issue: #57642
+trait X {
+    type G;
+    fn make_g() -> Self::G;
+}
+
+impl<'a> X for fn(&'a ()) {
+    type G = &'a ();
+
+    fn make_g() -> Self::G {
+        &()
+    }
+}
+
+fn g() {
+    let x = <fn (&())>::make_g(); //~ ERROR no function or associated item
+}
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-57362-2.stderr b/src/test/ui/issues/issue-57362-2.stderr
new file mode 100644
index 0000000000000..b8211691f7be6
--- /dev/null
+++ b/src/test/ui/issues/issue-57362-2.stderr
@@ -0,0 +1,15 @@
+error[E0599]: no function or associated item named `make_g` found for type `for<'r> fn(&'r ())` in the current scope
+  --> $DIR/issue-57362-2.rs:22:25
+   |
+LL |     let x = <fn (&())>::make_g(); //~ ERROR no function or associated item
+   |             ------------^^^^^^
+   |             |
+   |             function or associated item not found in `for<'r> fn(&'r ())`
+   |
+   = help: items from traits can only be used if the trait is implemented and in scope
+   = note: the following trait defines an item `make_g`, perhaps you need to implement it:
+           candidate #1: `X`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/issues/issue-57410-1.rs b/src/test/ui/issues/issue-57410-1.rs
new file mode 100644
index 0000000000000..dab77bd660ca0
--- /dev/null
+++ b/src/test/ui/issues/issue-57410-1.rs
@@ -0,0 +1,18 @@
+// compile-pass
+
+// Originally from #53925.
+// Tests that the `unreachable_pub` lint doesn't fire for `pub self::bar::Bar`.
+
+#![deny(unreachable_pub)]
+
+mod foo {
+    mod bar {
+        pub struct Bar;
+    }
+
+    pub use self::bar::Bar;
+}
+
+pub use foo::Bar;
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-57410.rs b/src/test/ui/issues/issue-57410.rs
new file mode 100644
index 0000000000000..0d697e5619d24
--- /dev/null
+++ b/src/test/ui/issues/issue-57410.rs
@@ -0,0 +1,17 @@
+// compile-pass
+
+// Tests that the `unreachable_pub` lint doesn't fire for `pub self::imp::f`.
+
+#![deny(unreachable_pub)]
+
+mod m {
+    mod imp {
+        pub fn f() {}
+    }
+
+    pub use self::imp::f;
+}
+
+pub use self::m::f;
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-57597.rs b/src/test/ui/issues/issue-57597.rs
new file mode 100644
index 0000000000000..ebeb3fe07adb4
--- /dev/null
+++ b/src/test/ui/issues/issue-57597.rs
@@ -0,0 +1,80 @@
+// Regression test for #57597.
+//
+// Make sure that nested matchers work correctly rather than causing an infinite loop or crash.
+
+// edition:2018
+
+macro_rules! foo1 {
+    ($($($i:ident)?)+) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo2 {
+    ($($($i:ident)?)*) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo3 {
+    ($($($i:ident)?)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo4 {
+    ($($($($i:ident)?)?)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo5 {
+    ($($($($i:ident)*)?)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo6 {
+    ($($($($i:ident)?)*)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo7 {
+    ($($($($i:ident)?)?)*) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo8 {
+    ($($($($i:ident)*)*)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo9 {
+    ($($($($i:ident)?)*)*) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo10 {
+    ($($($($i:ident)?)*)+) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo11 {
+    ($($($($i:ident)+)?)*) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+macro_rules! foo12 {
+    ($($($($i:ident)+)*)?) => {};
+    //~^ ERROR repetition matches empty token tree
+}
+
+fn main() {
+    foo1!();
+    foo2!();
+    foo3!();
+    foo4!();
+    foo5!();
+    foo6!();
+    foo7!();
+    foo8!();
+    foo9!();
+    foo10!();
+    foo11!();
+    foo12!();
+}
diff --git a/src/test/ui/issues/issue-57597.stderr b/src/test/ui/issues/issue-57597.stderr
new file mode 100644
index 0000000000000..0a02ac8c499b6
--- /dev/null
+++ b/src/test/ui/issues/issue-57597.stderr
@@ -0,0 +1,74 @@
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:8:7
+   |
+LL |     ($($($i:ident)?)+) => {};
+   |       ^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:13:7
+   |
+LL |     ($($($i:ident)?)*) => {};
+   |       ^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:18:7
+   |
+LL |     ($($($i:ident)?)?) => {};
+   |       ^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:23:7
+   |
+LL |     ($($($($i:ident)?)?)?) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:28:7
+   |
+LL |     ($($($($i:ident)*)?)?) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:33:7
+   |
+LL |     ($($($($i:ident)?)*)?) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:38:7
+   |
+LL |     ($($($($i:ident)?)?)*) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:43:7
+   |
+LL |     ($($($($i:ident)*)*)?) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:48:7
+   |
+LL |     ($($($($i:ident)?)*)*) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:53:7
+   |
+LL |     ($($($($i:ident)?)*)+) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:58:7
+   |
+LL |     ($($($($i:ident)+)?)*) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: repetition matches empty token tree
+  --> $DIR/issue-57597.rs:63:7
+   |
+LL |     ($($($($i:ident)+)*)?) => {};
+   |       ^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 12 previous errors
+
diff --git a/src/test/ui/issues/issue-57684.fixed b/src/test/ui/issues/issue-57684.fixed
new file mode 100644
index 0000000000000..4a432206d51e1
--- /dev/null
+++ b/src/test/ui/issues/issue-57684.fixed
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This test checks that the following error is emitted when a `=` character is used to initialize
+// a struct field when a `:` is expected.
+//
+// ```
+// error: struct fields are initialized with a colon
+//   --> $DIR/issue-57684.rs:12:20
+//    |
+// LL |     let _ = X { f1 = 5 };
+//    |                    ^ help: replace equals symbol with a colon: `:`
+// ```
+
+struct X {
+    f1: i32,
+}
+
+struct Y {
+    f1: i32,
+    f2: i32,
+    f3: i32,
+}
+
+fn main() {
+    let _ = X { f1: 5 };
+    //~^ ERROR expected `:`, found `=`
+
+    let f3 = 3;
+    let _ = Y {
+        f1: 5,
+        //~^ ERROR expected `:`, found `=`
+        f2: 4,
+        f3,
+    };
+}
diff --git a/src/test/ui/issues/issue-57684.rs b/src/test/ui/issues/issue-57684.rs
new file mode 100644
index 0000000000000..7a62785e32f1c
--- /dev/null
+++ b/src/test/ui/issues/issue-57684.rs
@@ -0,0 +1,37 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This test checks that the following error is emitted when a `=` character is used to initialize
+// a struct field when a `:` is expected.
+//
+// ```
+// error: struct fields are initialized with a colon
+//   --> $DIR/issue-57684.rs:12:20
+//    |
+// LL |     let _ = X { f1 = 5 };
+//    |                    ^ help: replace equals symbol with a colon: `:`
+// ```
+
+struct X {
+    f1: i32,
+}
+
+struct Y {
+    f1: i32,
+    f2: i32,
+    f3: i32,
+}
+
+fn main() {
+    let _ = X { f1 = 5 };
+    //~^ ERROR expected `:`, found `=`
+
+    let f3 = 3;
+    let _ = Y {
+        f1 = 5,
+        //~^ ERROR expected `:`, found `=`
+        f2: 4,
+        f3,
+    };
+}
diff --git a/src/test/ui/issues/issue-57684.stderr b/src/test/ui/issues/issue-57684.stderr
new file mode 100644
index 0000000000000..514bbffde6b1e
--- /dev/null
+++ b/src/test/ui/issues/issue-57684.stderr
@@ -0,0 +1,18 @@
+error: expected `:`, found `=`
+  --> $DIR/issue-57684.rs:27:20
+   |
+LL |     let _ = X { f1 = 5 };
+   |                   -^
+   |                   |
+   |                   help: replace equals symbol with a colon: `:`
+
+error: expected `:`, found `=`
+  --> $DIR/issue-57684.rs:32:12
+   |
+LL |         f1 = 5,
+   |           -^
+   |           |
+   |           help: replace equals symbol with a colon: `:`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/issues/issue-57741-1.rs b/src/test/ui/issues/issue-57741-1.rs
new file mode 100644
index 0000000000000..d0aae23b2fce6
--- /dev/null
+++ b/src/test/ui/issues/issue-57741-1.rs
@@ -0,0 +1,18 @@
+#![allow(warnings)]
+
+// This tests that the `help: consider dereferencing the boxed value` suggestion isn't made
+// because the box doesn't deref to the type of the arm.
+
+enum S {
+    A { a: usize },
+    B { b: usize },
+}
+
+fn main() {
+    let x = Box::new(3u32);
+    let y = match x {
+        S::A { a } | S::B { b: a } => a,
+        //~^ ERROR mismatched types [E0308]
+        //~^^ ERROR mismatched types [E0308]
+    };
+}
diff --git a/src/test/ui/issues/issue-57741-1.stderr b/src/test/ui/issues/issue-57741-1.stderr
new file mode 100644
index 0000000000000..d36424b83b4e1
--- /dev/null
+++ b/src/test/ui/issues/issue-57741-1.stderr
@@ -0,0 +1,25 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-57741-1.rs:14:9
+   |
+LL |     let y = match x {
+   |                   - this match expression has type `std::boxed::Box<u32>`
+LL |         S::A { a } | S::B { b: a } => a,
+   |         ^^^^^^^^^^ expected struct `std::boxed::Box`, found enum `S`
+   |
+   = note: expected type `std::boxed::Box<u32>`
+              found type `S`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-57741-1.rs:14:22
+   |
+LL |     let y = match x {
+   |                   - this match expression has type `std::boxed::Box<u32>`
+LL |         S::A { a } | S::B { b: a } => a,
+   |                      ^^^^^^^^^^^^^ expected struct `std::boxed::Box`, found enum `S`
+   |
+   = note: expected type `std::boxed::Box<u32>`
+              found type `S`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/issues/issue-57741.fixed b/src/test/ui/issues/issue-57741.fixed
new file mode 100644
index 0000000000000..4cae080033ca2
--- /dev/null
+++ b/src/test/ui/issues/issue-57741.fixed
@@ -0,0 +1,31 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This tests that the `help: consider dereferencing the boxed value` suggestion is made and works.
+
+enum S {
+    A { a: usize },
+    B { b: usize },
+}
+
+enum T {
+    A(usize),
+    B(usize),
+}
+
+fn main() {
+    let x = Box::new(T::A(3));
+    let y = match *x {
+        T::A(a) | T::B(a) => a,
+        //~^ ERROR mismatched types [E0308]
+        //~^^ ERROR mismatched types [E0308]
+    };
+
+    let x = Box::new(S::A { a: 3 });
+    let y = match *x {
+        S::A { a } | S::B { b: a } => a,
+        //~^ ERROR mismatched types [E0308]
+        //~^^ ERROR mismatched types [E0308]
+    };
+}
diff --git a/src/test/ui/issues/issue-57741.rs b/src/test/ui/issues/issue-57741.rs
new file mode 100644
index 0000000000000..e2658295af791
--- /dev/null
+++ b/src/test/ui/issues/issue-57741.rs
@@ -0,0 +1,31 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This tests that the `help: consider dereferencing the boxed value` suggestion is made and works.
+
+enum S {
+    A { a: usize },
+    B { b: usize },
+}
+
+enum T {
+    A(usize),
+    B(usize),
+}
+
+fn main() {
+    let x = Box::new(T::A(3));
+    let y = match x {
+        T::A(a) | T::B(a) => a,
+        //~^ ERROR mismatched types [E0308]
+        //~^^ ERROR mismatched types [E0308]
+    };
+
+    let x = Box::new(S::A { a: 3 });
+    let y = match x {
+        S::A { a } | S::B { b: a } => a,
+        //~^ ERROR mismatched types [E0308]
+        //~^^ ERROR mismatched types [E0308]
+    };
+}
diff --git a/src/test/ui/issues/issue-57741.stderr b/src/test/ui/issues/issue-57741.stderr
new file mode 100644
index 0000000000000..a26b1d20ca3cb
--- /dev/null
+++ b/src/test/ui/issues/issue-57741.stderr
@@ -0,0 +1,59 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-57741.rs:20:9
+   |
+LL |     let y = match x {
+   |                   -
+   |                   |
+   |                   this match expression has type `std::boxed::Box<T>`
+   |                   help: consider dereferencing the boxed value: `*x`
+LL |         T::A(a) | T::B(a) => a,
+   |         ^^^^^^^ expected struct `std::boxed::Box`, found enum `T`
+   |
+   = note: expected type `std::boxed::Box<T>`
+              found type `T`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-57741.rs:20:19
+   |
+LL |     let y = match x {
+   |                   -
+   |                   |
+   |                   this match expression has type `std::boxed::Box<T>`
+   |                   help: consider dereferencing the boxed value: `*x`
+LL |         T::A(a) | T::B(a) => a,
+   |                   ^^^^^^^ expected struct `std::boxed::Box`, found enum `T`
+   |
+   = note: expected type `std::boxed::Box<T>`
+              found type `T`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-57741.rs:27:9
+   |
+LL |     let y = match x {
+   |                   -
+   |                   |
+   |                   this match expression has type `std::boxed::Box<S>`
+   |                   help: consider dereferencing the boxed value: `*x`
+LL |         S::A { a } | S::B { b: a } => a,
+   |         ^^^^^^^^^^ expected struct `std::boxed::Box`, found enum `S`
+   |
+   = note: expected type `std::boxed::Box<S>`
+              found type `S`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-57741.rs:27:22
+   |
+LL |     let y = match x {
+   |                   -
+   |                   |
+   |                   this match expression has type `std::boxed::Box<S>`
+   |                   help: consider dereferencing the boxed value: `*x`
+LL |         S::A { a } | S::B { b: a } => a,
+   |                      ^^^^^^^^^^^^^ expected struct `std::boxed::Box`, found enum `S`
+   |
+   = note: expected type `std::boxed::Box<S>`
+              found type `S`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/issues/issue-57819.fixed b/src/test/ui/issues/issue-57819.fixed
new file mode 100644
index 0000000000000..3fab21db2d06e
--- /dev/null
+++ b/src/test/ui/issues/issue-57819.fixed
@@ -0,0 +1,47 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+//                                            ^^ help: remove extra angle brackets
+// ```
+
+trait Foo {
+    type Output;
+}
+
+fn foo<T: Foo>() {
+    // More complex cases with more than one correct leading `<` character:
+
+    bar::<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<T as Foo>::Output>();
+}
+
+fn bar<T>() {}
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+}
diff --git a/src/test/ui/issues/issue-57819.rs b/src/test/ui/issues/issue-57819.rs
new file mode 100644
index 0000000000000..5cafbf439be2d
--- /dev/null
+++ b/src/test/ui/issues/issue-57819.rs
@@ -0,0 +1,47 @@
+// run-rustfix
+
+#![allow(warnings)]
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+//                                            ^^ help: remove extra angle brackets
+// ```
+
+trait Foo {
+    type Output;
+}
+
+fn foo<T: Foo>() {
+    // More complex cases with more than one correct leading `<` character:
+
+    bar::<<<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<<T as Foo>::Output>();
+    //~^ ERROR unmatched angle bracket
+
+    bar::<<T as Foo>::Output>();
+}
+
+fn bar<T>() {}
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<<<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+}
diff --git a/src/test/ui/issues/issue-57819.stderr b/src/test/ui/issues/issue-57819.stderr
new file mode 100644
index 0000000000000..493e9835b1ca9
--- /dev/null
+++ b/src/test/ui/issues/issue-57819.stderr
@@ -0,0 +1,44 @@
+error: unmatched angle brackets
+  --> $DIR/issue-57819.rs:19:10
+   |
+LL |     bar::<<<<<T as Foo>::Output>();
+   |          ^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-57819.rs:22:10
+   |
+LL |     bar::<<<<T as Foo>::Output>();
+   |          ^^ help: remove extra angle brackets
+
+error: unmatched angle bracket
+  --> $DIR/issue-57819.rs:25:10
+   |
+LL |     bar::<<<T as Foo>::Output>();
+   |          ^ help: remove extra angle bracket
+
+error: unmatched angle brackets
+  --> $DIR/issue-57819.rs:34:48
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<<<<<Vec<usize>>();
+   |                                                ^^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-57819.rs:37:48
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<<<<Vec<usize>>();
+   |                                                ^^^ help: remove extra angle brackets
+
+error: unmatched angle brackets
+  --> $DIR/issue-57819.rs:40:48
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<<<Vec<usize>>();
+   |                                                ^^ help: remove extra angle brackets
+
+error: unmatched angle bracket
+  --> $DIR/issue-57819.rs:43:48
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<<Vec<usize>>();
+   |                                                ^ help: remove extra angle bracket
+
+error: aborting due to 7 previous errors
+
diff --git a/src/test/ui/issues/issue-57843.rs b/src/test/ui/issues/issue-57843.rs
new file mode 100644
index 0000000000000..466082552667b
--- /dev/null
+++ b/src/test/ui/issues/issue-57843.rs
@@ -0,0 +1,24 @@
+// Regression test for an ICE that occurred with the universes code:
+//
+// The signature of the closure `|_|` was being inferred to
+// `exists<'r> fn(&'r u8)`. This should result in a type error since
+// the signature `for<'r> fn(&'r u8)` is required. However, due to a
+// bug in the type variable generalization code, the placeholder for
+// `'r` was leaking out into the writeback phase, causing an ICE.
+
+trait ClonableFn<T> {
+    fn clone(&self) -> Box<dyn Fn(T)>;
+}
+
+impl<T, F: 'static> ClonableFn<T> for F
+where F: Fn(T) + Clone {
+    fn clone(&self) -> Box<dyn Fn(T)> {
+        Box::new(self.clone())
+    }
+}
+
+struct Foo(Box<dyn for<'a> ClonableFn<&'a bool>>);
+
+fn main() {
+    Foo(Box::new(|_| ())); //~ ERROR mismatched types
+}
diff --git a/src/test/ui/issues/issue-57843.stderr b/src/test/ui/issues/issue-57843.stderr
new file mode 100644
index 0000000000000..4ef884cb3f589
--- /dev/null
+++ b/src/test/ui/issues/issue-57843.stderr
@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-57843.rs:23:9
+   |
+LL |     Foo(Box::new(|_| ())); //~ ERROR mismatched types
+   |         ^^^^^^^^^^^^^^^^ one type is more general than the other
+   |
+   = note: expected type `std::ops::FnOnce<(&'a bool,)>`
+              found type `std::ops::FnOnce<(&bool,)>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/issues/issue-57866.rs b/src/test/ui/issues/issue-57866.rs
new file mode 100644
index 0000000000000..77c50e53868e1
--- /dev/null
+++ b/src/test/ui/issues/issue-57866.rs
@@ -0,0 +1,26 @@
+// compile-pass
+
+#![feature(type_alias_enum_variants)]
+
+enum Outer<T> {
+    A(T)
+}
+
+enum Inner {
+    A(i32)
+}
+
+type OuterAlias = Outer<Inner>;
+
+fn ice(x: OuterAlias) {
+    // Fine
+    match x {
+        OuterAlias::A(Inner::A(_)) => (),
+    }
+    // Not fine
+    match x {
+        OuterAlias::A(Inner::A(y)) => (),
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-57979.rs b/src/test/ui/issues/issue-57979.rs
new file mode 100644
index 0000000000000..abd46b60ab194
--- /dev/null
+++ b/src/test/ui/issues/issue-57979.rs
@@ -0,0 +1,42 @@
+// Regression test for #57979. This situation is meant to be an error.
+// As noted in the issue thread, we decided to forbid nested impl
+// trait of this kind:
+//
+// ```rust
+// fn foo() -> impl Foo<impl Bar> { .. }
+// ```
+//
+// Basically there are two hidden variables here, let's call them `X`
+// and `Y`, and we must prove that:
+//
+// ```
+// X: Foo<Y>
+// Y: Bar
+// ```
+//
+// However, the user is only giving us the return type `X`. It's true
+// that in some cases, we can infer `Y` from `X`, because `X` only
+// implements `Foo` for one type (and indeed the compiler does
+// inference of this kind), but I do recall that we intended to forbid
+// this -- in part because such inference is fragile, and there is not
+// necessarily a way for the user to be more explicit should the
+// inference fail (so you could get stuck with no way to port your
+// code forward if, for example, more impls are added to an existing
+// type).
+//
+// The same seems to apply in this situation. Here there are three impl traits, so we have
+//
+// ```
+// X: IntoIterator<Item = Y>
+// Y: Borrow<Data<Z>>
+// Z: AsRef<[u8]>
+// ```
+
+use std::borrow::Borrow;
+
+pub struct Data<TBody>(TBody);
+
+pub fn collect(_: impl IntoIterator<Item = impl Borrow<Data<impl AsRef<[u8]>>>>) {
+    //~^ ERROR
+    unimplemented!()
+}
diff --git a/src/test/ui/issues/issue-57979.stderr b/src/test/ui/issues/issue-57979.stderr
new file mode 100644
index 0000000000000..488f30ab7c5a7
--- /dev/null
+++ b/src/test/ui/issues/issue-57979.stderr
@@ -0,0 +1,17 @@
+error[E0666]: nested `impl Trait` is not allowed
+  --> $DIR/issue-57979.rs:39:61
+   |
+LL | pub fn collect(_: impl IntoIterator<Item = impl Borrow<Data<impl AsRef<[u8]>>>>) {
+   |                                            -----------------^^^^^^^^^^^^^^^^--
+   |                                            |                |
+   |                                            |                nested `impl Trait` here
+   |                                            outer `impl Trait`
+
+error[E0601]: `main` function not found in crate `issue_57979`
+   |
+   = note: consider adding a `main` function to `$DIR/issue-57979.rs`
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0601, E0666.
+For more information about an error, try `rustc --explain E0601`.
diff --git a/src/test/ui/issues/issue-58006.rs b/src/test/ui/issues/issue-58006.rs
new file mode 100644
index 0000000000000..1fb5fefa7596d
--- /dev/null
+++ b/src/test/ui/issues/issue-58006.rs
@@ -0,0 +1,15 @@
+#![feature(type_alias_enum_variants)]
+pub enum Enum {
+    A(usize),
+}
+
+impl Enum {
+    fn foo(&self) -> () {
+        match self {
+            Self::A => (),
+            //~^ ERROR expected unit struct/variant or constant, found tuple variant
+        }
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/issues/issue-58006.stderr b/src/test/ui/issues/issue-58006.stderr
new file mode 100644
index 0000000000000..c65e3e2777fae
--- /dev/null
+++ b/src/test/ui/issues/issue-58006.stderr
@@ -0,0 +1,9 @@
+error[E0533]: expected unit struct/variant or constant, found tuple variant `<Self>::A`
+  --> $DIR/issue-58006.rs:9:13
+   |
+LL |             Self::A => (),
+   |             ^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0533`.
diff --git a/src/test/ui/issues/issue-5997-enum.rs b/src/test/ui/issues/issue-5997-enum.rs
index 0987117ecd402..3ff4e036c60be 100644
--- a/src/test/ui/issues/issue-5997-enum.rs
+++ b/src/test/ui/issues/issue-5997-enum.rs
@@ -1,6 +1,6 @@
 fn f<Z>() -> bool {
     enum E { V(Z) }
-    //~^ ERROR can't use type parameters from outer function
+    //~^ ERROR can't use generic parameters from outer function
     true
 }
 
diff --git a/src/test/ui/issues/issue-5997-enum.stderr b/src/test/ui/issues/issue-5997-enum.stderr
index 5c26dc92c8584..5c778143e13dd 100644
--- a/src/test/ui/issues/issue-5997-enum.stderr
+++ b/src/test/ui/issues/issue-5997-enum.stderr
@@ -1,12 +1,12 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-5997-enum.rs:2:16
    |
 LL | fn f<Z>() -> bool {
    |    - - type variable from outer function
    |    |
-   |    try adding a local type parameter in this method instead
+   |    try adding a local generic parameter in this method instead
 LL |     enum E { V(Z) }
-   |                ^ use of type variable from outer function
+   |                ^ use of generic parameter from outer function
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-5997-struct.rs b/src/test/ui/issues/issue-5997-struct.rs
index 04ac489a55c50..6cf510b0a9d75 100644
--- a/src/test/ui/issues/issue-5997-struct.rs
+++ b/src/test/ui/issues/issue-5997-struct.rs
@@ -1,5 +1,5 @@
 fn f<T>() -> bool {
-    struct S(T); //~ ERROR can't use type parameters from outer function
+    struct S(T); //~ ERROR can't use generic parameters from outer function
 
     true
 }
diff --git a/src/test/ui/issues/issue-5997-struct.stderr b/src/test/ui/issues/issue-5997-struct.stderr
index 1d05d13242e8e..a60987b3f98ba 100644
--- a/src/test/ui/issues/issue-5997-struct.stderr
+++ b/src/test/ui/issues/issue-5997-struct.stderr
@@ -1,12 +1,12 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/issue-5997-struct.rs:2:14
    |
 LL | fn f<T>() -> bool {
    |    - - type variable from outer function
    |    |
-   |    try adding a local type parameter in this method instead
-LL |     struct S(T); //~ ERROR can't use type parameters from outer function
-   |              ^ use of type variable from outer function
+   |    try adding a local generic parameter in this method instead
+LL |     struct S(T); //~ ERROR can't use generic parameters from outer function
+   |              ^ use of generic parameter from outer function
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue_56411_aux.rs b/src/test/ui/issues/issue_56411_aux.rs
new file mode 100644
index 0000000000000..bd689e913aba6
--- /dev/null
+++ b/src/test/ui/issues/issue_56411_aux.rs
@@ -0,0 +1,5 @@
+// compile-pass
+
+struct T {}
+
+fn main() {}
diff --git a/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.rs b/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.rs
new file mode 100644
index 0000000000000..622709e7de584
--- /dev/null
+++ b/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.rs
@@ -0,0 +1,36 @@
+#![feature(rustc_attrs)]
+
+// Show that `homogeneous_aggregate` code ignores zero-length C
+// arrays.  This matches the recent C standard, though not the
+// behavior of all older compilers, which somtimes consider `T[0]` to
+// be a "flexible array member" (see discussion on #56877 for
+// details).
+
+#[repr(C)]
+pub struct Foo {
+    x: u32
+}
+
+#[repr(C)]
+pub struct Middle {
+    pub a: f32,
+    pub foo: [Foo; 0],
+    pub b: f32,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type TestMiddle = Middle;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+#[repr(C)]
+pub struct Final {
+    pub a: f32,
+    pub b: f32,
+    pub foo: [Foo; 0],
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type TestFinal = Final;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+fn main() { }
diff --git a/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.stderr b/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.stderr
new file mode 100644
index 0000000000000..0d44260635187
--- /dev/null
+++ b/src/test/ui/layout/homogeneous-aggr-zero-sized-c-struct.stderr
@@ -0,0 +1,14 @@
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-c-struct.rs:22:1
+   |
+LL | pub type TestMiddle = Middle;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-c-struct.rs:33:1
+   |
+LL | pub type TestFinal = Final;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.rs b/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.rs
new file mode 100644
index 0000000000000..4b429412aebfc
--- /dev/null
+++ b/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.rs
@@ -0,0 +1,73 @@
+#![feature(rustc_attrs)]
+
+// Regression test for #56877. We want to ensure that the presence of
+// `PhantomData` does not prevent `Bar` from being considered a
+// homogeneous aggregate.
+
+#[repr(C)]
+pub struct BaseCase {
+    pub a: f32,
+    pub b: f32,
+}
+
+#[repr(C)]
+pub struct WithPhantomData {
+    pub a: f32,
+    pub b: f32,
+    pub _unit: std::marker::PhantomData<()>,
+}
+
+pub struct EmptyRustStruct {
+}
+
+#[repr(C)]
+pub struct WithEmptyRustStruct {
+    pub a: f32,
+    pub b: f32,
+    pub _unit: EmptyRustStruct,
+}
+
+pub struct TransitivelyEmptyRustStruct {
+    field: EmptyRustStruct,
+    array: [u32; 0],
+}
+
+#[repr(C)]
+pub struct WithTransitivelyEmptyRustStruct {
+    pub a: f32,
+    pub b: f32,
+    pub _unit: TransitivelyEmptyRustStruct,
+}
+
+pub enum EmptyRustEnum {
+    Dummy,
+}
+
+#[repr(C)]
+pub struct WithEmptyRustEnum {
+    pub a: f32,
+    pub b: f32,
+    pub _unit: EmptyRustEnum,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type Test1 = BaseCase;
+//~^ ERROR homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type Test2 = WithPhantomData;
+//~^ ERROR homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type Test3 = WithEmptyRustStruct;
+//~^ ERROR homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type Test4 = WithTransitivelyEmptyRustStruct;
+//~^ ERROR homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+
+#[rustc_layout(homogeneous_aggregate)]
+pub type Test5 = WithEmptyRustEnum;
+//~^ ERROR homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+
+fn main() { }
diff --git a/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.stderr b/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.stderr
new file mode 100644
index 0000000000000..be04ba3e7f6cb
--- /dev/null
+++ b/src/test/ui/layout/homogeneous-aggr-zero-sized-repr-rust.stderr
@@ -0,0 +1,32 @@
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-repr-rust.rs:54:1
+   |
+LL | pub type Test1 = BaseCase;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-repr-rust.rs:58:1
+   |
+LL | pub type Test2 = WithPhantomData;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-repr-rust.rs:62:1
+   |
+LL | pub type Test3 = WithEmptyRustStruct;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-repr-rust.rs:66:1
+   |
+LL | pub type Test4 = WithTransitivelyEmptyRustStruct;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/homogeneous-aggr-zero-sized-repr-rust.rs:70:1
+   |
+LL | pub type Test5 = WithEmptyRustEnum;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+
diff --git a/src/test/ui/layout/zero-sized-array-union.rs b/src/test/ui/layout/zero-sized-array-union.rs
new file mode 100644
index 0000000000000..68b218249eb9a
--- /dev/null
+++ b/src/test/ui/layout/zero-sized-array-union.rs
@@ -0,0 +1,95 @@
+#![feature(rustc_attrs)]
+
+// Various tests around the behavior of zero-sized arrays and
+// unions. This matches the behavior of modern C compilers, though
+// older compilers (and sometimes clang) treat `T[0]` as a "flexible
+// array member". See more
+// details in #56877.
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty { }
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty2 {
+    e: Empty
+}
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty3 {
+    z: [f32; 0],
+}
+
+#[derive(Copy, Clone)]
+#[repr(C)]
+struct Empty4 {
+    e: Empty3
+}
+
+#[repr(C)]
+union U1 {
+    s: Empty
+}
+
+#[repr(C)]
+union U2 {
+    s: Empty2
+}
+
+#[repr(C)]
+union U3 {
+    s: Empty3
+}
+
+#[repr(C)]
+union U4 {
+    s: Empty4
+}
+
+#[repr(C)]
+struct Baz1 {
+    x: f32,
+    y: f32,
+    u: U1,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz1 = Baz1;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+#[repr(C)]
+struct Baz2 {
+    x: f32,
+    y: f32,
+    u: U2,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz2 = Baz2;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+#[repr(C)]
+struct Baz3 {
+    x: f32,
+    y: f32,
+    u: U3,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz3 = Baz3;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+#[repr(C)]
+struct Baz4 {
+    x: f32,
+    y: f32,
+    u: U4,
+}
+
+#[rustc_layout(homogeneous_aggregate)]
+type TestBaz4 = Baz4;
+//~^ ERROR homogeneous_aggregate: Homogeneous
+
+fn main() { }
diff --git a/src/test/ui/layout/zero-sized-array-union.stderr b/src/test/ui/layout/zero-sized-array-union.stderr
new file mode 100644
index 0000000000000..1bb31aaf7b7b9
--- /dev/null
+++ b/src/test/ui/layout/zero-sized-array-union.stderr
@@ -0,0 +1,26 @@
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/zero-sized-array-union.rs:59:1
+   |
+LL | type TestBaz1 = Baz1;
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/zero-sized-array-union.rs:70:1
+   |
+LL | type TestBaz2 = Baz2;
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/zero-sized-array-union.rs:81:1
+   |
+LL | type TestBaz3 = Baz3;
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: homogeneous_aggregate: Homogeneous(Reg { kind: Float, size: Size { raw: 4 } })
+  --> $DIR/zero-sized-array-union.rs:92:1
+   |
+LL | type TestBaz4 = Baz4;
+   | ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/lifetime-before-type-params.rs b/src/test/ui/lifetime-before-type-params.rs
new file mode 100644
index 0000000000000..9b905d4883a16
--- /dev/null
+++ b/src/test/ui/lifetime-before-type-params.rs
@@ -0,0 +1,9 @@
+#![allow(unused)]
+fn first<T, 'a, 'b>() {}
+//~^ ERROR lifetime parameters must be declared prior to type parameters
+fn second<'a, T, 'b>() {}
+//~^ ERROR lifetime parameters must be declared prior to type parameters
+fn third<T, U, 'a>() {}
+//~^ ERROR lifetime parameters must be declared prior to type parameters
+fn fourth<'a, T, 'b, U, 'c, V>() {}
+//~^ ERROR lifetime parameters must be declared prior to type parameters
diff --git a/src/test/ui/lifetime-before-type-params.stderr b/src/test/ui/lifetime-before-type-params.stderr
new file mode 100644
index 0000000000000..3cef5db66c66f
--- /dev/null
+++ b/src/test/ui/lifetime-before-type-params.stderr
@@ -0,0 +1,31 @@
+error: lifetime parameters must be declared prior to type parameters
+  --> $DIR/lifetime-before-type-params.rs:2:13
+   |
+LL | fn first<T, 'a, 'b>() {}
+   |         ----^^--^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type parameters
+  --> $DIR/lifetime-before-type-params.rs:4:18
+   |
+LL | fn second<'a, T, 'b>() {}
+   |          --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
+
+error: lifetime parameters must be declared prior to type parameters
+  --> $DIR/lifetime-before-type-params.rs:6:16
+   |
+LL | fn third<T, U, 'a>() {}
+   |         -------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, T, U>`
+
+error: lifetime parameters must be declared prior to type parameters
+  --> $DIR/lifetime-before-type-params.rs:8:18
+   |
+LL | fn fourth<'a, T, 'b, U, 'c, V>() {}
+   |          --------^^-----^^---- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, 'c, T, U, V>`
+
+error[E0601]: `main` function not found in crate `lifetime_before_type_params`
+   |
+   = note: consider adding a `main` function to `$DIR/lifetime-before-type-params.rs`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0601`.
diff --git a/src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr b/src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
index ab12aef2474f3..8fd98e0a3db2e 100644
--- a/src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
+++ b/src/test/ui/lint/issue-47390-unused-variable-in-struct-pattern.stderr
@@ -2,7 +2,7 @@ warning: unused variable: `i_think_continually`
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:26:9
    |
 LL |     let i_think_continually = 2;
-   |         ^^^^^^^^^^^^^^^^^^^ help: consider using `_i_think_continually` instead
+   |         ^^^^^^^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_i_think_continually`
    |
 note: lint level defined here
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:5:9
@@ -15,19 +15,19 @@ warning: unused variable: `mut_unused_var`
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:33:13
    |
 LL |     let mut mut_unused_var = 1;
-   |             ^^^^^^^^^^^^^^ help: consider using `_mut_unused_var` instead
+   |             ^^^^^^^^^^^^^^ help: consider prefixing with an underscore: `_mut_unused_var`
 
 warning: unused variable: `var`
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:35:14
    |
 LL |     let (mut var, unused_var) = (1, 2);
-   |              ^^^ help: consider using `_var` instead
+   |              ^^^ help: consider prefixing with an underscore: `_var`
 
 warning: unused variable: `unused_var`
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:35:19
    |
 LL |     let (mut var, unused_var) = (1, 2);
-   |                   ^^^^^^^^^^ help: consider using `_unused_var` instead
+   |                   ^^^^^^^^^^ help: consider prefixing with an underscore: `_unused_var`
 
 warning: unused variable: `corridors_of_light`
   --> $DIR/issue-47390-unused-variable-in-struct-pattern.rs:37:26
diff --git a/src/test/ui/lint/lint-group-nonstandard-style.rs b/src/test/ui/lint/lint-group-nonstandard-style.rs
index 0386daaa59b07..bd7f327bc0f63 100644
--- a/src/test/ui/lint/lint-group-nonstandard-style.rs
+++ b/src/test/ui/lint/lint-group-nonstandard-style.rs
@@ -19,7 +19,7 @@ mod test {
 
         fn CamelCase() {} //~ WARN should have a snake
 
-        struct snake_case; //~ WARN should have a camel
+        struct snake_case; //~ WARN should have an upper camel
     }
 }
 
diff --git a/src/test/ui/lint/lint-group-nonstandard-style.stderr b/src/test/ui/lint/lint-group-nonstandard-style.stderr
index f3c7d70054b77..ab36cda57ec80 100644
--- a/src/test/ui/lint/lint-group-nonstandard-style.stderr
+++ b/src/test/ui/lint/lint-group-nonstandard-style.stderr
@@ -1,8 +1,8 @@
-warning: type `snake_case` should have a camel case name
+warning: type `snake_case` should have an upper camel case name
   --> $DIR/lint-group-nonstandard-style.rs:22:16
    |
-LL |         struct snake_case; //~ WARN should have a camel
-   |                ^^^^^^^^^^ help: convert the identifier to camel case: `SnakeCase`
+LL |         struct snake_case; //~ WARN should have an upper camel
+   |                ^^^^^^^^^^ help: convert the identifier to upper camel case: `SnakeCase`
    |
 note: lint level defined here
   --> $DIR/lint-group-nonstandard-style.rs:18:17
diff --git a/src/test/ui/lint/lint-incoherent-auto-trait-objects.rs b/src/test/ui/lint/lint-incoherent-auto-trait-objects.rs
new file mode 100644
index 0000000000000..0d18965ee7338
--- /dev/null
+++ b/src/test/ui/lint/lint-incoherent-auto-trait-objects.rs
@@ -0,0 +1,21 @@
+// ignore-tidy-linelength
+
+trait Foo {}
+
+impl Foo for dyn Send {}
+
+impl Foo for dyn Send + Send {}
+//~^ ERROR conflicting implementations
+//~| hard error
+
+impl Foo for dyn Send + Sync {}
+
+impl Foo for dyn Sync + Send {}
+//~^ ERROR conflicting implementations
+//~| hard error
+
+impl Foo for dyn Send + Sync + Send {}
+//~^ ERROR conflicting implementations
+//~| hard error
+
+fn main() {}
diff --git a/src/test/ui/lint/lint-incoherent-auto-trait-objects.stderr b/src/test/ui/lint/lint-incoherent-auto-trait-objects.stderr
new file mode 100644
index 0000000000000..928c92ef91655
--- /dev/null
+++ b/src/test/ui/lint/lint-incoherent-auto-trait-objects.stderr
@@ -0,0 +1,39 @@
+error: conflicting implementations of trait `Foo` for type `(dyn std::marker::Send + 'static)`: (E0119)
+  --> $DIR/lint-incoherent-auto-trait-objects.rs:7:1
+   |
+LL | impl Foo for dyn Send {}
+   | --------------------- first implementation here
+LL | 
+LL | impl Foo for dyn Send + Send {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `(dyn std::marker::Send + 'static)`
+   |
+   = note: #[deny(order_dependent_trait_objects)] on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #56484 <https://github.com/rust-lang/rust/issues/56484>
+
+error: conflicting implementations of trait `Foo` for type `(dyn std::marker::Send + std::marker::Sync + 'static)`: (E0119)
+  --> $DIR/lint-incoherent-auto-trait-objects.rs:13:1
+   |
+LL | impl Foo for dyn Send + Sync {}
+   | ---------------------------- first implementation here
+LL | 
+LL | impl Foo for dyn Sync + Send {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `(dyn std::marker::Send + std::marker::Sync + 'static)`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #56484 <https://github.com/rust-lang/rust/issues/56484>
+
+error: conflicting implementations of trait `Foo` for type `(dyn std::marker::Send + std::marker::Sync + 'static)`: (E0119)
+  --> $DIR/lint-incoherent-auto-trait-objects.rs:17:1
+   |
+LL | impl Foo for dyn Sync + Send {}
+   | ---------------------------- first implementation here
+...
+LL | impl Foo for dyn Send + Sync + Send {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `(dyn std::marker::Send + std::marker::Sync + 'static)`
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #56484 <https://github.com/rust-lang/rust/issues/56484>
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/lint/lint-non-camel-case-types.rs b/src/test/ui/lint/lint-non-camel-case-types.rs
index bca1992605b77..d3b119a944109 100644
--- a/src/test/ui/lint/lint-non-camel-case-types.rs
+++ b/src/test/ui/lint/lint-non-camel-case-types.rs
@@ -2,43 +2,35 @@
 #![allow(dead_code)]
 
 struct ONE_TWO_THREE;
-//~^ ERROR type `ONE_TWO_THREE` should have a camel case name
+//~^ ERROR type `ONE_TWO_THREE` should have an upper camel case name
 
-struct foo { //~ ERROR type `foo` should have a camel case name
+struct foo { //~ ERROR type `foo` should have an upper camel case name
     bar: isize,
 }
 
-enum foo2 { //~ ERROR type `foo2` should have a camel case name
+enum foo2 { //~ ERROR type `foo2` should have an upper camel case name
     Bar
 }
 
-struct foo3 { //~ ERROR type `foo3` should have a camel case name
+struct foo3 { //~ ERROR type `foo3` should have an upper camel case name
     bar: isize
 }
 
-type foo4 = isize; //~ ERROR type `foo4` should have a camel case name
+type foo4 = isize; //~ ERROR type `foo4` should have an upper camel case name
 
 enum Foo5 {
-    bar //~ ERROR variant `bar` should have a camel case name
+    bar //~ ERROR variant `bar` should have an upper camel case name
 }
 
-trait foo6 { //~ ERROR trait `foo6` should have a camel case name
+trait foo6 { //~ ERROR trait `foo6` should have an upper camel case name
     fn dummy(&self) { }
 }
 
-fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have a camel case name
+fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have an upper camel case name
 
 #[repr(C)]
 struct foo7 {
     bar: isize,
 }
 
-struct X86_64;
-
-struct X86__64; //~ ERROR type `X86__64` should have a camel case name
-
-struct Abc_123; //~ ERROR type `Abc_123` should have a camel case name
-
-struct A1_b2_c3; //~ ERROR type `A1_b2_c3` should have a camel case name
-
 fn main() { }
diff --git a/src/test/ui/lint/lint-non-camel-case-types.stderr b/src/test/ui/lint/lint-non-camel-case-types.stderr
index 74f9a5993b859..7afacf64d8778 100644
--- a/src/test/ui/lint/lint-non-camel-case-types.stderr
+++ b/src/test/ui/lint/lint-non-camel-case-types.stderr
@@ -1,8 +1,8 @@
-error: type `ONE_TWO_THREE` should have a camel case name
+error: type `ONE_TWO_THREE` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:4:8
    |
 LL | struct ONE_TWO_THREE;
-   |        ^^^^^^^^^^^^^ help: convert the identifier to camel case: `OneTwoThree`
+   |        ^^^^^^^^^^^^^ help: convert the identifier to upper camel case: `OneTwoThree`
    |
 note: lint level defined here
   --> $DIR/lint-non-camel-case-types.rs:1:11
@@ -10,65 +10,47 @@ note: lint level defined here
 LL | #![forbid(non_camel_case_types)]
    |           ^^^^^^^^^^^^^^^^^^^^
 
-error: type `foo` should have a camel case name
+error: type `foo` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:7:8
    |
-LL | struct foo { //~ ERROR type `foo` should have a camel case name
-   |        ^^^ help: convert the identifier to camel case: `Foo`
+LL | struct foo { //~ ERROR type `foo` should have an upper camel case name
+   |        ^^^ help: convert the identifier to upper camel case: `Foo`
 
-error: type `foo2` should have a camel case name
+error: type `foo2` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:11:6
    |
-LL | enum foo2 { //~ ERROR type `foo2` should have a camel case name
-   |      ^^^^ help: convert the identifier to camel case: `Foo2`
+LL | enum foo2 { //~ ERROR type `foo2` should have an upper camel case name
+   |      ^^^^ help: convert the identifier to upper camel case: `Foo2`
 
-error: type `foo3` should have a camel case name
+error: type `foo3` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:15:8
    |
-LL | struct foo3 { //~ ERROR type `foo3` should have a camel case name
-   |        ^^^^ help: convert the identifier to camel case: `Foo3`
+LL | struct foo3 { //~ ERROR type `foo3` should have an upper camel case name
+   |        ^^^^ help: convert the identifier to upper camel case: `Foo3`
 
-error: type `foo4` should have a camel case name
+error: type `foo4` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:19:6
    |
-LL | type foo4 = isize; //~ ERROR type `foo4` should have a camel case name
-   |      ^^^^ help: convert the identifier to camel case: `Foo4`
+LL | type foo4 = isize; //~ ERROR type `foo4` should have an upper camel case name
+   |      ^^^^ help: convert the identifier to upper camel case: `Foo4`
 
-error: variant `bar` should have a camel case name
+error: variant `bar` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:22:5
    |
-LL |     bar //~ ERROR variant `bar` should have a camel case name
-   |     ^^^ help: convert the identifier to camel case: `Bar`
+LL |     bar //~ ERROR variant `bar` should have an upper camel case name
+   |     ^^^ help: convert the identifier to upper camel case: `Bar`
 
-error: trait `foo6` should have a camel case name
+error: trait `foo6` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:25:7
    |
-LL | trait foo6 { //~ ERROR trait `foo6` should have a camel case name
-   |       ^^^^ help: convert the identifier to camel case: `Foo6`
+LL | trait foo6 { //~ ERROR trait `foo6` should have an upper camel case name
+   |       ^^^^ help: convert the identifier to upper camel case: `Foo6`
 
-error: type parameter `ty` should have a camel case name
+error: type parameter `ty` should have an upper camel case name
   --> $DIR/lint-non-camel-case-types.rs:29:6
    |
-LL | fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have a camel case name
-   |      ^^ help: convert the identifier to camel case: `Ty`
+LL | fn f<ty>(_: ty) {} //~ ERROR type parameter `ty` should have an upper camel case name
+   |      ^^ help: convert the identifier to upper camel case: `Ty`
 
-error: type `X86__64` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:38:8
-   |
-LL | struct X86__64; //~ ERROR type `X86__64` should have a camel case name
-   |        ^^^^^^^ help: convert the identifier to camel case: `X86_64`
-
-error: type `Abc_123` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:40:8
-   |
-LL | struct Abc_123; //~ ERROR type `Abc_123` should have a camel case name
-   |        ^^^^^^^ help: convert the identifier to camel case: `Abc123`
-
-error: type `A1_b2_c3` should have a camel case name
-  --> $DIR/lint-non-camel-case-types.rs:42:8
-   |
-LL | struct A1_b2_c3; //~ ERROR type `A1_b2_c3` should have a camel case name
-   |        ^^^^^^^^ help: convert the identifier to camel case: `A1B2C3`
-
-error: aborting due to 11 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/test/ui/lint/lint-removed-allow.stderr b/src/test/ui/lint/lint-removed-allow.stderr
index 3af983165eb17..f796a14d63796 100644
--- a/src/test/ui/lint/lint-removed-allow.stderr
+++ b/src/test/ui/lint/lint-removed-allow.stderr
@@ -2,7 +2,7 @@ error: unused variable: `unused`
   --> $DIR/lint-removed-allow.rs:8:17
    |
 LL | fn main() { let unused = (); } //~ ERROR unused
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-removed-allow.rs:7:8
diff --git a/src/test/ui/lint/lint-removed-cmdline.stderr b/src/test/ui/lint/lint-removed-cmdline.stderr
index 191509c5a180c..d46ef6b9237fd 100644
--- a/src/test/ui/lint/lint-removed-cmdline.stderr
+++ b/src/test/ui/lint/lint-removed-cmdline.stderr
@@ -6,7 +6,7 @@ error: unused variable: `unused`
   --> $DIR/lint-removed-cmdline.rs:12:17
    |
 LL | fn main() { let unused = (); }
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-removed-cmdline.rs:11:8
diff --git a/src/test/ui/lint/lint-removed.stderr b/src/test/ui/lint/lint-removed.stderr
index 34fa85b0d8b9f..55f010348fe1e 100644
--- a/src/test/ui/lint/lint-removed.stderr
+++ b/src/test/ui/lint/lint-removed.stderr
@@ -10,7 +10,7 @@ error: unused variable: `unused`
   --> $DIR/lint-removed.rs:8:17
    |
 LL | fn main() { let unused = (); } //~ ERROR unused
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-removed.rs:7:8
diff --git a/src/test/ui/lint/lint-renamed-allow.stderr b/src/test/ui/lint/lint-renamed-allow.stderr
index 390b4c3f38abd..b2eeeae8f8e6d 100644
--- a/src/test/ui/lint/lint-renamed-allow.stderr
+++ b/src/test/ui/lint/lint-renamed-allow.stderr
@@ -2,7 +2,7 @@ error: unused variable: `unused`
   --> $DIR/lint-renamed-allow.rs:8:17
    |
 LL | fn main() { let unused = (); } //~ ERROR unused
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-renamed-allow.rs:7:8
diff --git a/src/test/ui/lint/lint-renamed-cmdline.stderr b/src/test/ui/lint/lint-renamed-cmdline.stderr
index 78a05bdc89f01..6247ee0aff833 100644
--- a/src/test/ui/lint/lint-renamed-cmdline.stderr
+++ b/src/test/ui/lint/lint-renamed-cmdline.stderr
@@ -6,7 +6,7 @@ error: unused variable: `unused`
   --> $DIR/lint-renamed-cmdline.rs:8:17
    |
 LL | fn main() { let unused = (); }
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-renamed-cmdline.rs:7:8
diff --git a/src/test/ui/lint/lint-renamed.stderr b/src/test/ui/lint/lint-renamed.stderr
index 1296fef5a4c63..b140a93ab38bd 100644
--- a/src/test/ui/lint/lint-renamed.stderr
+++ b/src/test/ui/lint/lint-renamed.stderr
@@ -10,7 +10,7 @@ error: unused variable: `unused`
   --> $DIR/lint-renamed.rs:4:17
    |
 LL | fn main() { let unused = (); } //~ ERROR unused
-   |                 ^^^^^^ help: consider using `_unused` instead
+   |                 ^^^^^^ help: consider prefixing with an underscore: `_unused`
    |
 note: lint level defined here
   --> $DIR/lint-renamed.rs:3:8
diff --git a/src/test/ui/lint/lint-unused-imports.rs b/src/test/ui/lint/lint-unused-imports.rs
index 489252479fef3..9c5b206203c1d 100644
--- a/src/test/ui/lint/lint-unused-imports.rs
+++ b/src/test/ui/lint/lint-unused-imports.rs
@@ -6,7 +6,7 @@ use bar::c::cc as cal;
 use std::mem::*;            // shouldn't get errors for not using
                             // everything imported
 use std::fmt::{};
-//~^ ERROR unused import: `use std::fmt::{};`
+//~^ ERROR unused import: `std::fmt::{}`
 
 // Should get errors for both 'Some' and 'None'
 use std::option::Option::{Some, None};
diff --git a/src/test/ui/lint/lint-unused-imports.stderr b/src/test/ui/lint/lint-unused-imports.stderr
index 214f4a472dc7e..18f2fae0067eb 100644
--- a/src/test/ui/lint/lint-unused-imports.stderr
+++ b/src/test/ui/lint/lint-unused-imports.stderr
@@ -1,8 +1,8 @@
-error: unused import: `use std::fmt::{};`
-  --> $DIR/lint-unused-imports.rs:8:1
+error: unused import: `std::fmt::{}`
+  --> $DIR/lint-unused-imports.rs:8:5
    |
 LL | use std::fmt::{};
-   | ^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^
    |
 note: lint level defined here
   --> $DIR/lint-unused-imports.rs:1:9
diff --git a/src/test/ui/lint/lint-uppercase-variables.stderr b/src/test/ui/lint/lint-uppercase-variables.stderr
index 0741179c4a4dd..f2267f351ddda 100644
--- a/src/test/ui/lint/lint-uppercase-variables.stderr
+++ b/src/test/ui/lint/lint-uppercase-variables.stderr
@@ -8,7 +8,7 @@ warning: unused variable: `Foo`
   --> $DIR/lint-uppercase-variables.rs:22:9
    |
 LL |         Foo => {}
-   |         ^^^ help: consider using `_Foo` instead
+   |         ^^^ help: consider prefixing with an underscore: `_Foo`
    |
 note: lint level defined here
   --> $DIR/lint-uppercase-variables.rs:1:9
diff --git a/src/test/ui/lint/suggestions.rs b/src/test/ui/lint/suggestions.rs
index a497953d73a05..67bd6dd501bd8 100644
--- a/src/test/ui/lint/suggestions.rs
+++ b/src/test/ui/lint/suggestions.rs
@@ -10,7 +10,7 @@
 #[no_mangle]
 //~^ HELP remove this attribute
 pub fn defiant<T>(_t: T) {}
-//~^ WARN functions generic over types must be mangled
+//~^ WARN functions generic over types or consts must be mangled
 
 #[no_mangle]
 fn rio_grande() {}
@@ -23,7 +23,7 @@ mod badlands {
     //~^ ERROR const items should never be #[no_mangle]
     //~| HELP try a static value
     #[no_mangle] pub fn val_jean<T>() {}
-    //~^ WARN functions generic over types must be mangled
+    //~^ WARN functions generic over types or consts must be mangled
     //~| HELP remove this attribute
 
     // ... but we can suggest just-`pub` instead of restricted
@@ -31,7 +31,7 @@ mod badlands {
     //~^ ERROR const items should never be #[no_mangle]
     //~| HELP try a static value
     #[no_mangle] pub(crate) fn crossfield<T>() {}
-    //~^ WARN functions generic over types must be mangled
+    //~^ WARN functions generic over types or consts must be mangled
     //~| HELP remove this attribute
 }
 
diff --git a/src/test/ui/lint/suggestions.stderr b/src/test/ui/lint/suggestions.stderr
index c70f17f95d028..1e4eabc9db0f7 100644
--- a/src/test/ui/lint/suggestions.stderr
+++ b/src/test/ui/lint/suggestions.stderr
@@ -54,7 +54,7 @@ LL | #[no_mangle] const DISCOVERY: usize = 1;
    |
    = note: #[deny(no_mangle_const_items)] on by default
 
-warning: functions generic over types must be mangled
+warning: functions generic over types or consts must be mangled
   --> $DIR/suggestions.rs:12:1
    |
 LL | #[no_mangle]
@@ -73,7 +73,7 @@ LL |     #[no_mangle] pub const DAUNTLESS: bool = true;
    |                  |
    |                  help: try a static value: `pub static`
 
-warning: functions generic over types must be mangled
+warning: functions generic over types or consts must be mangled
   --> $DIR/suggestions.rs:25:18
    |
 LL |     #[no_mangle] pub fn val_jean<T>() {}
@@ -89,7 +89,7 @@ LL |     #[no_mangle] pub(crate) const VETAR: bool = true;
    |                  |
    |                  help: try a static value: `pub static`
 
-warning: functions generic over types must be mangled
+warning: functions generic over types or consts must be mangled
   --> $DIR/suggestions.rs:33:18
    |
 LL |     #[no_mangle] pub(crate) fn crossfield<T>() {}
diff --git a/src/test/ui/liveness/liveness-dead.rs b/src/test/ui/liveness/liveness-dead.rs
index 7d420afde4b72..004663c85ee50 100644
--- a/src/test/ui/liveness/liveness-dead.rs
+++ b/src/test/ui/liveness/liveness-dead.rs
@@ -27,4 +27,13 @@ fn f5(mut x: i32) {
     x = 4; //~ ERROR: value assigned to `x` is never read
 }
 
+// #22630
+fn f6() {
+    let mut done = false;
+    while !done {
+        done = true; // no error
+        continue;
+    }
+}
+
 fn main() {}
diff --git a/src/test/ui/liveness/liveness-forgot-ret.stderr b/src/test/ui/liveness/liveness-forgot-ret.stderr
index bbcbbdbe8dd5b..a970b80fdbbd9 100644
--- a/src/test/ui/liveness/liveness-forgot-ret.stderr
+++ b/src/test/ui/liveness/liveness-forgot-ret.stderr
@@ -2,7 +2,7 @@ error[E0308]: mismatched types
   --> $DIR/liveness-forgot-ret.rs:3:19
    |
 LL | fn f(a: isize) -> isize { if god_exists(a) { return 5; }; }
-   |    -              ^^^^^ expected isize, found ()    - expected because of this statement
+   |    -              ^^^^^ expected isize, found ()
    |    |
    |    this function's body doesn't return
    |
diff --git a/src/test/ui/liveness/liveness-move-call-arg.nll.stderr b/src/test/ui/liveness/liveness-move-call-arg.nll.stderr
index 3aa89ac8a9b71..521304d560554 100644
--- a/src/test/ui/liveness/liveness-move-call-arg.nll.stderr
+++ b/src/test/ui/liveness/liveness-move-call-arg.nll.stderr
@@ -1,10 +1,11 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/liveness-move-call-arg.rs:9:14
    |
+LL |     let x: Box<isize> = box 25;
+   |         - move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+LL |     loop {
 LL |         take(x); //~ ERROR use of moved value: `x`
    |              ^ value moved here, in previous iteration of loop
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/liveness/liveness-move-in-loop.nll.stderr b/src/test/ui/liveness/liveness-move-in-loop.nll.stderr
index 8a5a18f3316c7..b7e973bc9140d 100644
--- a/src/test/ui/liveness/liveness-move-in-loop.nll.stderr
+++ b/src/test/ui/liveness/liveness-move-in-loop.nll.stderr
@@ -1,10 +1,11 @@
 error[E0382]: use of moved value: `y`
   --> $DIR/liveness-move-in-loop.rs:11:25
    |
+LL |     let y: Box<isize> = box 42;
+   |         - move occurs because `y` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+...
 LL |                     x = y; //~ ERROR use of moved value
    |                         ^ value moved here, in previous iteration of loop
-   |
-   = note: move occurs because `y` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/liveness/liveness-move-in-while.nll.stderr b/src/test/ui/liveness/liveness-move-in-while.nll.stderr
index 081983d8bf016..167dcc6b64372 100644
--- a/src/test/ui/liveness/liveness-move-in-while.nll.stderr
+++ b/src/test/ui/liveness/liveness-move-in-while.nll.stderr
@@ -1,12 +1,13 @@
 error[E0382]: borrow of moved value: `y`
   --> $DIR/liveness-move-in-while.rs:7:24
    |
+LL |     let y: Box<isize> = box 42;
+   |         - move occurs because `y` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
+...
 LL |         println!("{}", y); //~ ERROR use of moved value: `y`
    |                        ^ value borrowed here after move
 LL |         while true { while true { while true { x = y; x.clone(); } } }
    |                                                    - value moved here, in previous iteration of loop
-   |
-   = note: move occurs because `y` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/liveness/liveness-unused.stderr b/src/test/ui/liveness/liveness-unused.stderr
index 17cdacb859f02..49795faa59c8d 100644
--- a/src/test/ui/liveness/liveness-unused.stderr
+++ b/src/test/ui/liveness/liveness-unused.stderr
@@ -15,7 +15,7 @@ error: unused variable: `x`
   --> $DIR/liveness-unused.rs:8:7
    |
 LL | fn f1(x: isize) {
-   |       ^ help: consider using `_x` instead
+   |       ^ help: consider prefixing with an underscore: `_x`
    |
 note: lint level defined here
   --> $DIR/liveness-unused.rs:2:9
@@ -27,19 +27,19 @@ error: unused variable: `x`
   --> $DIR/liveness-unused.rs:12:8
    |
 LL | fn f1b(x: &mut isize) {
-   |        ^ help: consider using `_x` instead
+   |        ^ help: consider prefixing with an underscore: `_x`
 
 error: unused variable: `x`
   --> $DIR/liveness-unused.rs:20:9
    |
 LL |     let x: isize;
-   |         ^ help: consider using `_x` instead
+   |         ^ help: consider prefixing with an underscore: `_x`
 
 error: unused variable: `x`
   --> $DIR/liveness-unused.rs:25:9
    |
 LL |     let x = 3;
-   |         ^ help: consider using `_x` instead
+   |         ^ help: consider prefixing with an underscore: `_x`
 
 error: variable `x` is assigned to, but never used
   --> $DIR/liveness-unused.rs:30:13
@@ -74,25 +74,25 @@ error: unused variable: `i`
   --> $DIR/liveness-unused.rs:59:12
    |
 LL |       Some(i) => {
-   |            ^ help: consider using `_i` instead
+   |            ^ help: consider prefixing with an underscore: `_i`
 
 error: unused variable: `x`
   --> $DIR/liveness-unused.rs:79:9
    |
 LL |     for x in 1..10 { }
-   |         ^ help: consider using `_x` instead
+   |         ^ help: consider prefixing with an underscore: `_x`
 
 error: unused variable: `x`
   --> $DIR/liveness-unused.rs:84:10
    |
 LL |     for (x, _) in [1, 2, 3].iter().enumerate() { }
-   |          ^ help: consider using `_x` instead
+   |          ^ help: consider prefixing with an underscore: `_x`
 
 error: unused variable: `x`
   --> $DIR/liveness-unused.rs:89:13
    |
 LL |     for (_, x) in [1, 2, 3].iter().enumerate() {
-   |             ^ help: consider using `_x` instead
+   |             ^ help: consider prefixing with an underscore: `_x`
 
 error: variable `x` is assigned to, but never used
   --> $DIR/liveness-unused.rs:112:9
diff --git a/src/test/ui/liveness/liveness-use-after-move.nll.stderr b/src/test/ui/liveness/liveness-use-after-move.nll.stderr
index 45fd43687f39b..36c25882ccd4f 100644
--- a/src/test/ui/liveness/liveness-use-after-move.nll.stderr
+++ b/src/test/ui/liveness/liveness-use-after-move.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/liveness-use-after-move.rs:6:20
    |
+LL |     let x: Box<_> = box 5;
+   |         - move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 LL |     let y = x;
    |             - value moved here
 LL |     println!("{}", *x); //~ ERROR use of moved value: `*x`
    |                    ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/liveness/liveness-use-after-send.nll.stderr b/src/test/ui/liveness/liveness-use-after-send.nll.stderr
index 2b55b5d59732b..d9367c871165a 100644
--- a/src/test/ui/liveness/liveness-use-after-send.nll.stderr
+++ b/src/test/ui/liveness/liveness-use-after-send.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `message`
   --> $DIR/liveness-use-after-send.rs:16:20
    |
+LL | fn test00_start(ch: Chan<Box<isize>>, message: Box<isize>, _count: Box<isize>) {
+   |                                       ------- move occurs because `message` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 LL |     send(ch, message);
    |              ------- value moved here
 LL |     println!("{}", message); //~ ERROR use of moved value: `message`
    |                    ^^^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `message` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/lub-glb/old-lub-glb-hr.rs b/src/test/ui/lub-glb/old-lub-glb-hr.rs
index 324dc86bd92b8..6bf1fd41d77be 100644
--- a/src/test/ui/lub-glb/old-lub-glb-hr.rs
+++ b/src/test/ui/lub-glb/old-lub-glb-hr.rs
@@ -4,7 +4,8 @@
 // longer get an error, because we recognize these two types as
 // equivalent!
 //
-// compile-pass
+// Whoops -- now that we reinstituted the leak-check, we get an error
+// again.
 
 fn foo(
     x: fn(&u8, &u8),
@@ -12,7 +13,7 @@ fn foo(
 ) {
     let z = match 22 {
         0 => x,
-        _ => y,
+        _ => y, //~ ERROR match arms have incompatible types
     };
 }
 
diff --git a/src/test/ui/lub-glb/old-lub-glb-hr.stderr b/src/test/ui/lub-glb/old-lub-glb-hr.stderr
new file mode 100644
index 0000000000000..8f228ea4cad41
--- /dev/null
+++ b/src/test/ui/lub-glb/old-lub-glb-hr.stderr
@@ -0,0 +1,18 @@
+error[E0308]: match arms have incompatible types
+  --> $DIR/old-lub-glb-hr.rs:16:14
+   |
+LL |       let z = match 22 {
+   |  _____________-
+LL | |         0 => x,
+   | |              - this is found to be of type `for<'r, 's> fn(&'r u8, &'s u8)`
+LL | |         _ => y, //~ ERROR match arms have incompatible types
+   | |              ^ expected bound lifetime parameter, found concrete lifetime
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note: expected type `for<'r, 's> fn(&'r u8, &'s u8)`
+              found type `for<'a> fn(&'a u8, &'a u8)`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/lub-glb/old-lub-glb-object.rs b/src/test/ui/lub-glb/old-lub-glb-object.rs
index 9be7a813603d4..dcd604a5157e2 100644
--- a/src/test/ui/lub-glb/old-lub-glb-object.rs
+++ b/src/test/ui/lub-glb/old-lub-glb-object.rs
@@ -7,9 +7,9 @@ fn foo(
     x: &for<'a, 'b> Foo<&'a u8, &'b u8>,
     y: &for<'a> Foo<&'a u8, &'a u8>,
 ) {
-    let z = match 22 { //~ ERROR E0308
+    let z = match 22 {
         0 => x,
-        _ => y,
+        _ => y, //~ ERROR match arms have incompatible types
     };
 }
 
diff --git a/src/test/ui/lub-glb/old-lub-glb-object.stderr b/src/test/ui/lub-glb/old-lub-glb-object.stderr
index 17d3648156b51..056f9131dd21c 100644
--- a/src/test/ui/lub-glb/old-lub-glb-object.stderr
+++ b/src/test/ui/lub-glb/old-lub-glb-object.stderr
@@ -1,15 +1,17 @@
-error[E0308]: mismatched types
-  --> $DIR/old-lub-glb-object.rs:10:13
+error[E0308]: match arms have incompatible types
+  --> $DIR/old-lub-glb-object.rs:12:14
    |
-LL |       let z = match 22 { //~ ERROR E0308
-   |  _____________^
+LL |       let z = match 22 {
+   |  _____________-
 LL | |         0 => x,
-LL | |         _ => y,
+   | |              - this is found to be of type `&dyn for<'a, 'b> Foo<&'a u8, &'b u8>`
+LL | |         _ => y, //~ ERROR match arms have incompatible types
+   | |              ^ expected bound lifetime parameter 'a, found concrete lifetime
 LL | |     };
-   | |_____^ one type is more general than the other
+   | |_____- `match` arms have incompatible types
    |
-   = note: expected type `dyn for<'a, 'b> Foo<&'a u8, &'b u8>`
-              found type `dyn for<'a> Foo<&'a u8, &'a u8>`
+   = note: expected type `&dyn for<'a, 'b> Foo<&'a u8, &'b u8>`
+              found type `&dyn for<'a> Foo<&'a u8, &'a u8>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/macro-follow.rs b/src/test/ui/macros/macro-follow.rs
index f4a1931da5aec..10b44e0017532 100644
--- a/src/test/ui/macros/macro-follow.rs
+++ b/src/test/ui/macros/macro-follow.rs
@@ -12,11 +12,11 @@ macro_rules! follow_pat {
     ($p:pat >) => {};        //~ERROR `$p:pat` is followed by `>`
     ($p:pat +) => {};        //~ERROR `$p:pat` is followed by `+`
     ($p:pat ident) => {};    //~ERROR `$p:pat` is followed by `ident`
-    ($p:pat $p:pat) => {};   //~ERROR `$p:pat` is followed by `$p:pat`
+    ($p:pat $q:pat) => {};   //~ERROR `$p:pat` is followed by `$q:pat`
     ($p:pat $e:expr) => {};  //~ERROR `$p:pat` is followed by `$e:expr`
     ($p:pat $t:ty) => {};    //~ERROR `$p:pat` is followed by `$t:ty`
     ($p:pat $s:stmt) => {};  //~ERROR `$p:pat` is followed by `$s:stmt`
-    ($p:pat $p:path) => {};  //~ERROR `$p:pat` is followed by `$p:path`
+    ($p:pat $q:path) => {};  //~ERROR `$p:pat` is followed by `$q:path`
     ($p:pat $b:block) => {}; //~ERROR `$p:pat` is followed by `$b:block`
     ($p:pat $i:ident) => {}; //~ERROR `$p:pat` is followed by `$i:ident`
     ($p:pat $t:tt) => {};    //~ERROR `$p:pat` is followed by `$t:tt`
@@ -37,7 +37,7 @@ macro_rules! follow_expr {
     ($e:expr if) => {};       //~ERROR `$e:expr` is followed by `if`
     ($e:expr in) => {};       //~ERROR `$e:expr` is followed by `in`
     ($e:expr $p:pat) => {};   //~ERROR `$e:expr` is followed by `$p:pat`
-    ($e:expr $e:expr) => {};  //~ERROR `$e:expr` is followed by `$e:expr`
+    ($e:expr $f:expr) => {};  //~ERROR `$e:expr` is followed by `$f:expr`
     ($e:expr $t:ty) => {};    //~ERROR `$e:expr` is followed by `$t:ty`
     ($e:expr $s:stmt) => {};  //~ERROR `$e:expr` is followed by `$s:stmt`
     ($e:expr $p:path) => {};  //~ERROR `$e:expr` is followed by `$p:path`
@@ -57,12 +57,12 @@ macro_rules! follow_ty {
     ($t:ty if) => {};       //~ERROR `$t:ty` is followed by `if`
     ($t:ty $p:pat) => {};   //~ERROR `$t:ty` is followed by `$p:pat`
     ($t:ty $e:expr) => {};  //~ERROR `$t:ty` is followed by `$e:expr`
-    ($t:ty $t:ty) => {};    //~ERROR `$t:ty` is followed by `$t:ty`
+    ($t:ty $r:ty) => {};    //~ERROR `$t:ty` is followed by `$r:ty`
     ($t:ty $s:stmt) => {};  //~ERROR `$t:ty` is followed by `$s:stmt`
     ($t:ty $p:path) => {};  //~ERROR `$t:ty` is followed by `$p:path`
     ($t:ty $b:block) => {}; // ok (RFC 1494)
     ($t:ty $i:ident) => {}; //~ERROR `$t:ty` is followed by `$i:ident`
-    ($t:ty $t:tt) => {};    //~ERROR `$t:ty` is followed by `$t:tt`
+    ($t:ty $r:tt) => {};    //~ERROR `$t:ty` is followed by `$r:tt`
     ($t:ty $i:item) => {};  //~ERROR `$t:ty` is followed by `$i:item`
     ($t:ty $m:meta) => {};  //~ERROR `$t:ty` is followed by `$m:meta`
 }
@@ -82,7 +82,7 @@ macro_rules! follow_stmt {
     ($s:stmt $p:pat) => {};   //~ERROR `$s:stmt` is followed by `$p:pat`
     ($s:stmt $e:expr) => {};  //~ERROR `$s:stmt` is followed by `$e:expr`
     ($s:stmt $t:ty) => {};    //~ERROR `$s:stmt` is followed by `$t:ty`
-    ($s:stmt $s:stmt) => {};  //~ERROR `$s:stmt` is followed by `$s:stmt`
+    ($s:stmt $t:stmt) => {};  //~ERROR `$s:stmt` is followed by `$t:stmt`
     ($s:stmt $p:path) => {};  //~ERROR `$s:stmt` is followed by `$p:path`
     ($s:stmt $b:block) => {}; //~ERROR `$s:stmt` is followed by `$b:block`
     ($s:stmt $i:ident) => {}; //~ERROR `$s:stmt` is followed by `$i:ident`
@@ -97,11 +97,11 @@ macro_rules! follow_path {
     ($p:path +) => {};        //~ERROR `$p:path` is followed by `+`
     ($p:path ident) => {};    //~ERROR `$p:path` is followed by `ident`
     ($p:path if) => {};       //~ERROR `$p:path` is followed by `if`
-    ($p:path $p:pat) => {};   //~ERROR `$p:path` is followed by `$p:pat`
+    ($p:path $q:pat) => {};   //~ERROR `$p:path` is followed by `$q:pat`
     ($p:path $e:expr) => {};  //~ERROR `$p:path` is followed by `$e:expr`
     ($p:path $t:ty) => {};    //~ERROR `$p:path` is followed by `$t:ty`
     ($p:path $s:stmt) => {};  //~ERROR `$p:path` is followed by `$s:stmt`
-    ($p:path $p:path) => {};  //~ERROR `$p:path` is followed by `$p:path`
+    ($p:path $q:path) => {};  //~ERROR `$p:path` is followed by `$q:path`
     ($p:path $b:block) => {}; // ok (RFC 1494)
     ($p:path $i:ident) => {}; //~ERROR `$p:path` is followed by `$i:ident`
     ($p:path $t:tt) => {};    //~ERROR `$p:path` is followed by `$t:tt`
diff --git a/src/test/ui/macros/macro-follow.stderr b/src/test/ui/macros/macro-follow.stderr
index 4aea5cc5de6bd..e3302eac4ac08 100644
--- a/src/test/ui/macros/macro-follow.stderr
+++ b/src/test/ui/macros/macro-follow.stderr
@@ -54,10 +54,10 @@ LL |     ($p:pat ident) => {};    //~ERROR `$p:pat` is followed by `ident`
    |
    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
-error: `$p:pat` is followed by `$p:pat`, which is not allowed for `pat` fragments
+error: `$p:pat` is followed by `$q:pat`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:15:13
    |
-LL |     ($p:pat $p:pat) => {};   //~ERROR `$p:pat` is followed by `$p:pat`
+LL |     ($p:pat $q:pat) => {};   //~ERROR `$p:pat` is followed by `$q:pat`
    |             ^^^^^^ not allowed after `pat` fragments
    |
    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
@@ -86,10 +86,10 @@ LL |     ($p:pat $s:stmt) => {};  //~ERROR `$p:pat` is followed by `$s:stmt`
    |
    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
-error: `$p:pat` is followed by `$p:path`, which is not allowed for `pat` fragments
+error: `$p:pat` is followed by `$q:path`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:19:13
    |
-LL |     ($p:pat $p:path) => {};  //~ERROR `$p:pat` is followed by `$p:path`
+LL |     ($p:pat $q:path) => {};  //~ERROR `$p:pat` is followed by `$q:path`
    |             ^^^^^^^ not allowed after `pat` fragments
    |
    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
@@ -230,10 +230,10 @@ LL |     ($e:expr $p:pat) => {};   //~ERROR `$e:expr` is followed by `$p:pat`
    |
    = note: allowed there are: `=>`, `,` or `;`
 
-error: `$e:expr` is followed by `$e:expr`, which is not allowed for `expr` fragments
+error: `$e:expr` is followed by `$f:expr`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:40:14
    |
-LL |     ($e:expr $e:expr) => {};  //~ERROR `$e:expr` is followed by `$e:expr`
+LL |     ($e:expr $f:expr) => {};  //~ERROR `$e:expr` is followed by `$f:expr`
    |              ^^^^^^^ not allowed after `expr` fragments
    |
    = note: allowed there are: `=>`, `,` or `;`
@@ -350,10 +350,10 @@ LL |     ($t:ty $e:expr) => {};  //~ERROR `$t:ty` is followed by `$e:expr`
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
-error: `$t:ty` is followed by `$t:ty`, which is not allowed for `ty` fragments
+error: `$t:ty` is followed by `$r:ty`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:60:12
    |
-LL |     ($t:ty $t:ty) => {};    //~ERROR `$t:ty` is followed by `$t:ty`
+LL |     ($t:ty $r:ty) => {};    //~ERROR `$t:ty` is followed by `$r:ty`
    |            ^^^^^ not allowed after `ty` fragments
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
@@ -382,10 +382,10 @@ LL |     ($t:ty $i:ident) => {}; //~ERROR `$t:ty` is followed by `$i:ident`
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
-error: `$t:ty` is followed by `$t:tt`, which is not allowed for `ty` fragments
+error: `$t:ty` is followed by `$r:tt`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:65:12
    |
-LL |     ($t:ty $t:tt) => {};    //~ERROR `$t:ty` is followed by `$t:tt`
+LL |     ($t:ty $r:tt) => {};    //~ERROR `$t:ty` is followed by `$r:tt`
    |            ^^^^^ not allowed after `ty` fragments
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
@@ -518,10 +518,10 @@ LL |     ($s:stmt $t:ty) => {};    //~ERROR `$s:stmt` is followed by `$t:ty`
    |
    = note: allowed there are: `=>`, `,` or `;`
 
-error: `$s:stmt` is followed by `$s:stmt`, which is not allowed for `stmt` fragments
+error: `$s:stmt` is followed by `$t:stmt`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:85:14
    |
-LL |     ($s:stmt $s:stmt) => {};  //~ERROR `$s:stmt` is followed by `$s:stmt`
+LL |     ($s:stmt $t:stmt) => {};  //~ERROR `$s:stmt` is followed by `$t:stmt`
    |              ^^^^^^^ not allowed after `stmt` fragments
    |
    = note: allowed there are: `=>`, `,` or `;`
@@ -606,10 +606,10 @@ LL |     ($p:path if) => {};       //~ERROR `$p:path` is followed by `if`
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
-error: `$p:path` is followed by `$p:pat`, which is not allowed for `path` fragments
+error: `$p:path` is followed by `$q:pat`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:100:14
    |
-LL |     ($p:path $p:pat) => {};   //~ERROR `$p:path` is followed by `$p:pat`
+LL |     ($p:path $q:pat) => {};   //~ERROR `$p:path` is followed by `$q:pat`
    |              ^^^^^^ not allowed after `path` fragments
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
@@ -638,10 +638,10 @@ LL |     ($p:path $s:stmt) => {};  //~ERROR `$p:path` is followed by `$s:stmt`
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
-error: `$p:path` is followed by `$p:path`, which is not allowed for `path` fragments
+error: `$p:path` is followed by `$q:path`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:104:14
    |
-LL |     ($p:path $p:path) => {};  //~ERROR `$p:path` is followed by `$p:path`
+LL |     ($p:path $q:path) => {};  //~ERROR `$p:path` is followed by `$q:path`
    |              ^^^^^^^ not allowed after `path` fragments
    |
    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
diff --git a/src/test/ui/macros/macro-multiple-matcher-bindings.rs b/src/test/ui/macros/macro-multiple-matcher-bindings.rs
new file mode 100644
index 0000000000000..9e0fa3887163d
--- /dev/null
+++ b/src/test/ui/macros/macro-multiple-matcher-bindings.rs
@@ -0,0 +1,25 @@
+// Test that duplicate matcher binding names are caught at declaration time, rather than at macro
+// invocation time.
+//
+// FIXME(mark-i-m): Update this when it becomes a hard error.
+
+// compile-pass
+
+#![allow(unused_macros)]
+
+macro_rules! foo1 {
+    ($a:ident, $a:ident) => {}; //~WARNING duplicate matcher binding
+    ($a:ident, $a:path) => {};  //~WARNING duplicate matcher binding
+}
+
+macro_rules! foo2 {
+    ($a:ident) => {}; // OK
+    ($a:path) => {};  // OK
+}
+
+macro_rules! foo3 {
+    ($a:ident, $($a:ident),*) => {}; //~WARNING duplicate matcher binding
+    ($($a:ident)+ # $($($a:path),+);*) => {}; //~WARNING duplicate matcher binding
+}
+
+fn main() {}
diff --git a/src/test/ui/macros/macro-multiple-matcher-bindings.stderr b/src/test/ui/macros/macro-multiple-matcher-bindings.stderr
new file mode 100644
index 0000000000000..bc78b471a2d1e
--- /dev/null
+++ b/src/test/ui/macros/macro-multiple-matcher-bindings.stderr
@@ -0,0 +1,37 @@
+warning: duplicate matcher binding
+  --> $DIR/macro-multiple-matcher-bindings.rs:11:6
+   |
+LL |     ($a:ident, $a:ident) => {}; //~WARNING duplicate matcher binding
+   |      ^^^^^^^^  ^^^^^^^^
+   |
+   = note: #[warn(duplicate_matcher_binding_name)] on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #57593 <https://github.com/rust-lang/rust/issues/57593>
+
+warning: duplicate matcher binding
+  --> $DIR/macro-multiple-matcher-bindings.rs:12:6
+   |
+LL |     ($a:ident, $a:path) => {};  //~WARNING duplicate matcher binding
+   |      ^^^^^^^^  ^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #57593 <https://github.com/rust-lang/rust/issues/57593>
+
+warning: duplicate matcher binding
+  --> $DIR/macro-multiple-matcher-bindings.rs:21:6
+   |
+LL |     ($a:ident, $($a:ident),*) => {}; //~WARNING duplicate matcher binding
+   |      ^^^^^^^^    ^^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #57593 <https://github.com/rust-lang/rust/issues/57593>
+
+warning: duplicate matcher binding
+  --> $DIR/macro-multiple-matcher-bindings.rs:22:8
+   |
+LL |     ($($a:ident)+ # $($($a:path),+);*) => {}; //~WARNING duplicate matcher binding
+   |        ^^^^^^^^         ^^^^^^^
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #57593 <https://github.com/rust-lang/rust/issues/57593>
+
diff --git a/src/test/ui/macros/macro-reexport-removed.stderr b/src/test/ui/macros/macro-reexport-removed.stderr
index 7c3555a92ed8b..6cfec3ee762dd 100644
--- a/src/test/ui/macros/macro-reexport-removed.stderr
+++ b/src/test/ui/macros/macro-reexport-removed.stderr
@@ -14,7 +14,7 @@ error[E0658]: The attribute `macro_reexport` is currently unknown to the compile
   --> $DIR/macro-reexport-removed.rs:5:3
    |
 LL | #[macro_reexport(macro_one)] //~ ERROR attribute `macro_reexport` is currently unknown
-   |   ^^^^^^^^^^^^^^
+   |   ^^^^^^^^^^^^^^ help: a built-in attribute with a similar name exists: `macro_export`
    |
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
 
diff --git a/src/test/ui/match-on-negative-integer-ranges.rs b/src/test/ui/match-on-negative-integer-ranges.rs
new file mode 100644
index 0000000000000..53e9ea9a5775b
--- /dev/null
+++ b/src/test/ui/match-on-negative-integer-ranges.rs
@@ -0,0 +1,7 @@
+// run-pass
+
+fn main() {
+    assert_eq!(false, match -50_i8 { -128i8..=-101i8 => true, _ => false, });
+
+    assert_eq!(false, if let -128i8..=-101i8 = -50_i8 { true } else { false });
+}
diff --git a/src/test/ui/match/match-type-err-first-arm.rs b/src/test/ui/match/match-type-err-first-arm.rs
new file mode 100644
index 0000000000000..b4b84ef8f1cec
--- /dev/null
+++ b/src/test/ui/match/match-type-err-first-arm.rs
@@ -0,0 +1,45 @@
+fn main() {
+    let _ = test_func1(1);
+    let _ = test_func2(1);
+}
+
+fn test_func1(n: i32) -> i32 {
+    //~^ NOTE expected `i32` because of return type
+    match n {
+        12 => 'b',
+        //~^ ERROR mismatched types
+        //~| NOTE expected i32, found char
+        _ => 42,
+    }
+}
+
+fn test_func2(n: i32) -> i32 {
+    let x = match n {
+    //~^ NOTE `match` arms have incompatible types
+        12 => 'b',
+        //~^ NOTE this is found to be of type `char`
+        _ => 42,
+        //~^ ERROR match arms have incompatible types
+        //~| NOTE expected char, found integer
+        //~| NOTE expected type `char`
+    };
+    x
+}
+
+fn test_func3(n: i32) -> i32 {
+    let x = match n {
+    //~^ NOTE `match` arms have incompatible types
+        1 => 'b',
+        2 => 'b',
+        3 => 'b',
+        4 => 'b',
+        5 => 'b',
+        6 => 'b',
+        //~^ NOTE this and all prior arms are found to be of type `char`
+        _ => 42,
+        //~^ ERROR match arms have incompatible types
+        //~| NOTE expected char, found integer
+        //~| NOTE expected type `char`
+    };
+    x
+}
diff --git a/src/test/ui/match/match-type-err-first-arm.stderr b/src/test/ui/match/match-type-err-first-arm.stderr
new file mode 100644
index 0000000000000..db8bef8dc7755
--- /dev/null
+++ b/src/test/ui/match/match-type-err-first-arm.stderr
@@ -0,0 +1,53 @@
+error[E0308]: mismatched types
+  --> $DIR/match-type-err-first-arm.rs:9:15
+   |
+LL | fn test_func1(n: i32) -> i32 {
+   |                          --- expected `i32` because of return type
+...
+LL |         12 => 'b',
+   |               ^^^ expected i32, found char
+
+error[E0308]: match arms have incompatible types
+  --> $DIR/match-type-err-first-arm.rs:21:14
+   |
+LL |       let x = match n {
+   |  _____________-
+LL | |     //~^ NOTE `match` arms have incompatible types
+LL | |         12 => 'b',
+   | |               --- this is found to be of type `char`
+LL | |         //~^ NOTE this is found to be of type `char`
+LL | |         _ => 42,
+   | |              ^^ expected char, found integer
+...  |
+LL | |         //~| NOTE expected type `char`
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note: expected type `char`
+              found type `{integer}`
+
+error[E0308]: match arms have incompatible types
+  --> $DIR/match-type-err-first-arm.rs:39:14
+   |
+LL |       let x = match n {
+   |  _____________-
+LL | |     //~^ NOTE `match` arms have incompatible types
+LL | |         1 => 'b',
+LL | |         2 => 'b',
+...  |
+LL | |         6 => 'b',
+   | |              --- this and all prior arms are found to be of type `char`
+LL | |         //~^ NOTE this and all prior arms are found to be of type `char`
+LL | |         _ => 42,
+   | |              ^^ expected char, found integer
+...  |
+LL | |         //~| NOTE expected type `char`
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note: expected type `char`
+              found type `{integer}`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.rs b/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.rs
new file mode 100644
index 0000000000000..a5dae1c71cdaa
--- /dev/null
+++ b/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.rs
@@ -0,0 +1,177 @@
+#![feature(arbitrary_self_types, coerce_unsized, dispatch_from_dyn, unsize, unsized_locals)]
+
+// This tests a few edge-cases around `arbitrary_self_types`. Most specifically,
+// it checks that the `ObjectCandidate` you get from method matching can't
+// match a trait with the same DefId as a supertrait but a bad type parameter.
+
+use std::marker::PhantomData;
+
+mod internal {
+    use std::ops::{CoerceUnsized, Deref, DispatchFromDyn};
+    use std::marker::{PhantomData, Unsize};
+
+    pub struct Smaht<T: ?Sized, MISC>(pub Box<T>, pub PhantomData<MISC>);
+
+    impl<T: ?Sized, MISC> Deref for Smaht<T, MISC> {
+        type Target = T;
+
+        fn deref(&self) -> &Self::Target {
+            &self.0
+        }
+    }
+    impl<T: ?Sized + Unsize<U>, U: ?Sized, MISC> CoerceUnsized<Smaht<U, MISC>>
+        for Smaht<T, MISC>
+    {}
+    impl<T: ?Sized + Unsize<U>, U: ?Sized, MISC> DispatchFromDyn<Smaht<U, MISC>>
+        for Smaht<T, MISC>
+    {}
+
+    pub trait Foo: X<u32> {}
+    pub trait X<T> {
+        fn foo(self: Smaht<Self, T>) -> T;
+    }
+
+    impl X<u32> for () {
+        fn foo(self: Smaht<Self, u32>) -> u32 {
+            0
+        }
+    }
+
+    pub trait Marker {}
+    impl Marker for dyn Foo {}
+    impl<T: Marker + ?Sized> X<u64> for T {
+        fn foo(self: Smaht<Self, u64>) -> u64 {
+            1
+        }
+    }
+
+    impl Deref for dyn Foo {
+        type Target = ();
+        fn deref(&self) -> &() { &() }
+    }
+
+    impl Foo for () {}
+}
+
+pub trait FinalFoo {
+    fn foo(&self) -> u8;
+}
+
+impl FinalFoo for () {
+    fn foo(&self) -> u8 { 0 }
+}
+
+mod nuisance_foo {
+    pub trait NuisanceFoo {
+        fn foo(self);
+    }
+
+    impl<T: ?Sized> NuisanceFoo for T {
+        fn foo(self) {}
+    }
+}
+
+
+fn objectcandidate_impl() {
+    let x: internal::Smaht<(), u32> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u32> = x;
+
+    // This picks `<dyn internal::Foo as X<u32>>::foo` via `ObjectCandidate`.
+    //
+    // The `TraitCandidate` is not relevant because `X` is not in scope.
+    let z = x.foo();
+
+    // Observe the type of `z` is `u32`
+    let _seetype: () = z; //~ ERROR mismatched types
+    //~| expected (), found u32
+}
+
+fn traitcandidate_impl() {
+    use internal::X;
+
+    let x: internal::Smaht<(), u64> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u64> = x;
+
+    // This picks `<dyn internal::Foo as X<u64>>::foo` via `TraitCandidate`.
+    //
+    // The `ObjectCandidate` does not apply, as it only applies to
+    // `X<u32>` (and not `X<u64>`).
+    let z = x.foo();
+
+    // Observe the type of `z` is `u64`
+    let _seetype: () = z; //~ ERROR mismatched types
+    //~| expected (), found u64
+}
+
+fn traitcandidate_impl_with_nuisance() {
+    use internal::X;
+    use nuisance_foo::NuisanceFoo;
+
+    let x: internal::Smaht<(), u64> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u64> = x;
+
+    // This picks `<dyn internal::Foo as X<u64>>::foo` via `TraitCandidate`.
+    //
+    // The `ObjectCandidate` does not apply, as it only applies to
+    // `X<u32>` (and not `X<u64>`).
+    //
+    // The NuisanceFoo impl has the same priority as the `X` impl,
+    // so we get a conflict.
+    let z = x.foo(); //~ ERROR multiple applicable items in scope
+}
+
+
+fn neither_impl() {
+    let x: internal::Smaht<(), u64> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u64> = x;
+
+    // This can't pick the `TraitCandidate` impl, because `Foo` is not
+    // imported. However, this also can't pick the `ObjectCandidate`
+    // impl, because it only applies to `X<u32>` (and not `X<u64>`).
+    //
+    // Therefore, neither of the candidates is applicable, and we pick
+    // the `FinalFoo` impl after another deref, which will return `u8`.
+    let z = x.foo();
+
+    // Observe the type of `z` is `u8`
+    let _seetype: () = z; //~ ERROR mismatched types
+    //~| expected (), found u8
+}
+
+fn both_impls() {
+    use internal::X;
+
+    let x: internal::Smaht<(), u32> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u32> = x;
+
+    // This can pick both the `TraitCandidate` and the `ObjectCandidate` impl.
+    //
+    // However, the `ObjectCandidate` is considered an "inherent candidate",
+    // and therefore has priority over both the `TraitCandidate` as well as
+    // any other "nuisance" candidate" (if present).
+    let z = x.foo();
+
+    // Observe the type of `z` is `u32`
+    let _seetype: () = z; //~ ERROR mismatched types
+    //~| expected (), found u32
+}
+
+
+fn both_impls_with_nuisance() {
+    // Similar to the `both_impls` example, except with a nuisance impl to
+    // make sure the `ObjectCandidate` indeed has a higher priority.
+
+    use internal::X;
+    use nuisance_foo::NuisanceFoo;
+
+    let x: internal::Smaht<(), u32> = internal::Smaht(Box::new(()), PhantomData);
+    let x: internal::Smaht<dyn internal::Foo, u32> = x;
+    let z = x.foo();
+
+    // Observe the type of `z` is `u32`
+    let _seetype: () = z; //~ ERROR mismatched types
+    //~| expected (), found u32
+}
+
+fn main() {
+}
diff --git a/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.stderr b/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.stderr
new file mode 100644
index 0000000000000..2d8449b96de41
--- /dev/null
+++ b/src/test/ui/methods/method-deref-to-same-trait-object-with-separate-params.stderr
@@ -0,0 +1,72 @@
+error[E0308]: mismatched types
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:85:24
+   |
+LL |     let _seetype: () = z; //~ ERROR mismatched types
+   |                        ^ expected (), found u32
+   |
+   = note: expected type `()`
+              found type `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:102:24
+   |
+LL |     let _seetype: () = z; //~ ERROR mismatched types
+   |                        ^ expected (), found u64
+   |
+   = note: expected type `()`
+              found type `u64`
+
+error[E0034]: multiple applicable items in scope
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:120:15
+   |
+LL |     let z = x.foo(); //~ ERROR multiple applicable items in scope
+   |               ^^^ multiple `foo` found
+   |
+note: candidate #1 is defined in an impl of the trait `internal::X` for the type `_`
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:43:9
+   |
+LL |         fn foo(self: Smaht<Self, u64>) -> u64 {
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl of the trait `nuisance_foo::NuisanceFoo` for the type `_`
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:70:9
+   |
+LL |         fn foo(self) {}
+   |         ^^^^^^^^^^^^
+note: candidate #3 is defined in the trait `FinalFoo`
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:57:5
+   |
+LL |     fn foo(&self) -> u8;
+   |     ^^^^^^^^^^^^^^^^^^^^
+   = help: to disambiguate the method call, write `FinalFoo::foo(x)` instead
+
+error[E0308]: mismatched types
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:137:24
+   |
+LL |     let _seetype: () = z; //~ ERROR mismatched types
+   |                        ^ expected (), found u8
+   |
+   = note: expected type `()`
+              found type `u8`
+
+error[E0308]: mismatched types
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:155:24
+   |
+LL |     let _seetype: () = z; //~ ERROR mismatched types
+   |                        ^ expected (), found u32
+   |
+   = note: expected type `()`
+              found type `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/method-deref-to-same-trait-object-with-separate-params.rs:172:24
+   |
+LL |     let _seetype: () = z; //~ ERROR mismatched types
+   |                        ^ expected (), found u32
+   |
+   = note: expected type `()`
+              found type `u32`
+
+error: aborting due to 6 previous errors
+
+Some errors occurred: E0034, E0308.
+For more information about an error, try `rustc --explain E0034`.
diff --git a/src/test/ui/methods/method-trait-object-with-hrtb.rs b/src/test/ui/methods/method-trait-object-with-hrtb.rs
new file mode 100644
index 0000000000000..da2f13f5a2f8a
--- /dev/null
+++ b/src/test/ui/methods/method-trait-object-with-hrtb.rs
@@ -0,0 +1,41 @@
+// compile-pass
+
+// Check that method probing ObjectCandidate works in the presence of
+// auto traits and/or HRTBs.
+
+mod internal {
+    pub trait MyObject<'a> {
+        type Output;
+
+        fn foo(&self) -> Self::Output;
+    }
+
+    impl<'a> MyObject<'a> for () {
+        type Output = &'a u32;
+
+        fn foo(&self) -> Self::Output { &4 }
+    }
+}
+
+fn t1(d: &dyn for<'a> internal::MyObject<'a, Output=&'a u32>) {
+    d.foo();
+}
+
+fn t2(d: &dyn internal::MyObject<'static, Output=&'static u32>) {
+    d.foo();
+}
+
+fn t3(d: &(dyn for<'a> internal::MyObject<'a, Output=&'a u32> + Sync)) {
+    d.foo();
+}
+
+fn t4(d: &(dyn internal::MyObject<'static, Output=&'static u32> + Sync)) {
+    d.foo();
+}
+
+fn main() {
+    t1(&());
+    t2(&());
+    t3(&());
+    t4(&());
+}
diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs b/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs
index 437150666be0c..521bd3695dfe5 100644
--- a/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs
+++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.rs
@@ -7,6 +7,6 @@ fn main() {
 
 fn baz<F: Fn(*mut &u32)>(_: F) {}
 fn _test<'a>(f: fn(*mut &'a u32)) {
-    baz(f); //~ ERROR mismatched types
-     //~| ERROR mismatched types
+    baz(f); //~ ERROR type mismatch
+     //~| ERROR type mismatch
 }
diff --git a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
index a6628006587c1..5dd6887005e83 100644
--- a/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
+++ b/src/test/ui/mismatched_types/closure-arg-type-mismatch.stderr
@@ -22,25 +22,34 @@ LL |     a.iter().map(|_: (u16, u16)| 45); //~ ERROR type mismatch
    |              |
    |              expected signature of `fn(&(u32, u32)) -> _`
 
-error[E0308]: mismatched types
+error[E0631]: type mismatch in function arguments
   --> $DIR/closure-arg-type-mismatch.rs:10:5
    |
-LL |     baz(f); //~ ERROR mismatched types
-   |     ^^^ one type is more general than the other
+LL |     baz(f); //~ ERROR type mismatch
+   |     ^^^
+   |     |
+   |     expected signature of `for<'r> fn(*mut &'r u32) -> _`
+   |     found signature of `fn(*mut &'a u32) -> _`
    |
-   = note: expected type `for<'r> std::ops::Fn<(*mut &'r u32,)>`
-              found type `std::ops::Fn<(*mut &'a u32,)>`
+note: required by `baz`
+  --> $DIR/closure-arg-type-mismatch.rs:8:1
+   |
+LL | fn baz<F: Fn(*mut &u32)>(_: F) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0308]: mismatched types
+error[E0271]: type mismatch resolving `for<'r> <fn(*mut &'a u32) as std::ops::FnOnce<(*mut &'r u32,)>>::Output == ()`
   --> $DIR/closure-arg-type-mismatch.rs:10:5
    |
-LL |     baz(f); //~ ERROR mismatched types
-   |     ^^^ one type is more general than the other
+LL |     baz(f); //~ ERROR type mismatch
+   |     ^^^ expected bound lifetime parameter, found concrete lifetime
+   |
+note: required by `baz`
+  --> $DIR/closure-arg-type-mismatch.rs:8:1
    |
-   = note: expected type `std::ops::FnOnce<(*mut &u32,)>`
-              found type `std::ops::FnOnce<(*mut &'a u32,)>`
+LL | fn baz<F: Fn(*mut &u32)>(_: F) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 5 previous errors
 
-Some errors occurred: E0308, E0631.
-For more information about an error, try `rustc --explain E0308`.
+Some errors occurred: E0271, E0631.
+For more information about an error, try `rustc --explain E0271`.
diff --git a/src/test/ui/mismatched_types/closure-mismatch.rs b/src/test/ui/mismatched_types/closure-mismatch.rs
index 152a525493732..40a4641fe7196 100644
--- a/src/test/ui/mismatched_types/closure-mismatch.rs
+++ b/src/test/ui/mismatched_types/closure-mismatch.rs
@@ -5,5 +5,6 @@ impl<T: Fn(&())> Foo for T {}
 fn baz<T: Foo>(_: T) {}
 
 fn main() {
-    baz(|_| ()); //~ ERROR E0308
+    baz(|_| ()); //~ ERROR type mismatch
+    //~^ ERROR type mismatch
 }
diff --git a/src/test/ui/mismatched_types/closure-mismatch.stderr b/src/test/ui/mismatched_types/closure-mismatch.stderr
index 0d87bc228755f..e55047e96c297 100644
--- a/src/test/ui/mismatched_types/closure-mismatch.stderr
+++ b/src/test/ui/mismatched_types/closure-mismatch.stderr
@@ -1,12 +1,32 @@
-error[E0308]: mismatched types
+error[E0271]: type mismatch resolving `for<'r> <[closure@$DIR/closure-mismatch.rs:8:9: 8:15] as std::ops::FnOnce<(&'r (),)>>::Output == ()`
   --> $DIR/closure-mismatch.rs:8:5
    |
-LL |     baz(|_| ()); //~ ERROR E0308
-   |     ^^^ one type is more general than the other
+LL |     baz(|_| ()); //~ ERROR type mismatch
+   |     ^^^ expected bound lifetime parameter, found concrete lifetime
    |
-   = note: expected type `for<'r> std::ops::Fn<(&'r (),)>`
-              found type `std::ops::Fn<(&(),)>`
+   = note: required because of the requirements on the impl of `Foo` for `[closure@$DIR/closure-mismatch.rs:8:9: 8:15]`
+note: required by `baz`
+  --> $DIR/closure-mismatch.rs:5:1
+   |
+LL | fn baz<T: Foo>(_: T) {}
+   | ^^^^^^^^^^^^^^^^^^^^
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/closure-mismatch.rs:8:5
+   |
+LL |     baz(|_| ()); //~ ERROR type mismatch
+   |     ^^^ ------ found signature of `fn(_) -> _`
+   |     |
+   |     expected signature of `for<'r> fn(&'r ()) -> _`
+   |
+   = note: required because of the requirements on the impl of `Foo` for `[closure@$DIR/closure-mismatch.rs:8:9: 8:15]`
+note: required by `baz`
+  --> $DIR/closure-mismatch.rs:5:1
+   |
+LL | fn baz<T: Foo>(_: T) {}
+   | ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
+Some errors occurred: E0271, E0631.
+For more information about an error, try `rustc --explain E0271`.
diff --git a/src/test/ui/mismatched_types/issue-36053-2.rs b/src/test/ui/mismatched_types/issue-36053-2.rs
index 9035e3380b0c5..9edfebcd49471 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.rs
+++ b/src/test/ui/mismatched_types/issue-36053-2.rs
@@ -7,4 +7,5 @@ fn main() {
     once::<&str>("str").fuse().filter(|a: &str| true).count();
     //~^ ERROR no method named `count`
     //~| ERROR type mismatch in closure arguments
+    //~| ERROR type mismatch in closure arguments
 }
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
index e53e8c520e0c4..c5c67e6bd9bd9 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.stderr
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -16,7 +16,15 @@ LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
    |                                |
    |                                expected signature of `for<'r> fn(&'r &str) -> _`
 
-error: aborting due to 2 previous errors
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/issue-36053-2.rs:7:32
+   |
+LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
+   |                                ^^^^^^ -------------- found signature of `for<'r> fn(&'r str) -> _`
+   |                                |
+   |                                expected signature of `fn(&&str) -> _`
+
+error: aborting due to 3 previous errors
 
 Some errors occurred: E0599, E0631.
 For more information about an error, try `rustc --explain E0599`.
diff --git a/src/test/ui/missing/missing-stability.rs b/src/test/ui/missing/missing-stability.rs
index 86841706325f7..469c22fdb17d7 100644
--- a/src/test/ui/missing/missing-stability.rs
+++ b/src/test/ui/missing/missing-stability.rs
@@ -6,7 +6,7 @@
 #![stable(feature = "stable_test_feature", since = "1.0.0")]
 
 pub fn unmarked() {
-    //~^ ERROR This node does not have a stability attribute
+    //~^ ERROR function has missing stability attribute
     ()
 }
 
@@ -20,5 +20,5 @@ pub mod foo {
 pub mod bar {
     // #[stable] is not inherited
     pub fn unmarked() {}
-    //~^ ERROR This node does not have a stability attribute
+    //~^ ERROR function has missing stability attribute
 }
diff --git a/src/test/ui/missing/missing-stability.stderr b/src/test/ui/missing/missing-stability.stderr
index e55bd00e2c673..6c81f2bac5788 100644
--- a/src/test/ui/missing/missing-stability.stderr
+++ b/src/test/ui/missing/missing-stability.stderr
@@ -1,13 +1,13 @@
-error: This node does not have a stability attribute
+error: function has missing stability attribute
   --> $DIR/missing-stability.rs:8:1
    |
 LL | / pub fn unmarked() {
-LL | |     //~^ ERROR This node does not have a stability attribute
+LL | |     //~^ ERROR function has missing stability attribute
 LL | |     ()
 LL | | }
    | |_^
 
-error: This node does not have a stability attribute
+error: function has missing stability attribute
   --> $DIR/missing-stability.rs:22:5
    |
 LL |     pub fn unmarked() {}
diff --git a/src/test/ui/moves/move-guard-same-consts.nll.stderr b/src/test/ui/moves/move-guard-same-consts.nll.stderr
new file mode 100644
index 0000000000000..43f99cabcae94
--- /dev/null
+++ b/src/test/ui/moves/move-guard-same-consts.nll.stderr
@@ -0,0 +1,14 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/move-guard-same-consts.rs:20:24
+   |
+LL |     let x: Box<_> = box 1;
+   |         - move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+...
+LL |         (1, 2) if take(x) => (),
+   |                        - value moved here
+LL |         (1, 2) if take(x) => (), //~ ERROR use of moved value: `x`
+   |                        ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/moves/move-in-guard-1.nll.stderr b/src/test/ui/moves/move-in-guard-1.nll.stderr
new file mode 100644
index 0000000000000..41abe6fa72a57
--- /dev/null
+++ b/src/test/ui/moves/move-in-guard-1.nll.stderr
@@ -0,0 +1,14 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/move-in-guard-1.rs:10:24
+   |
+LL |     let x: Box<_> = box 1;
+   |         - move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+...
+LL |         (1, _) if take(x) => (),
+   |                        - value moved here
+LL |         (_, 2) if take(x) => (), //~ ERROR use of moved value: `x`
+   |                        ^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/moves/move-in-guard-2.nll.stderr b/src/test/ui/moves/move-in-guard-2.nll.stderr
index 2d93944384609..0b14c1620d3cf 100644
--- a/src/test/ui/moves/move-in-guard-2.nll.stderr
+++ b/src/test/ui/moves/move-in-guard-2.nll.stderr
@@ -1,10 +1,11 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/move-in-guard-2.rs:10:24
    |
+LL |     let x: Box<_> = box 1;
+   |         - move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
+...
 LL |         (_, 2) if take(x) => (), //~ ERROR use of moved value: `x`
    |                        ^ value moved here, in previous iteration of loop
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/move-into-dead-array-2.nll.stderr b/src/test/ui/moves/move-into-dead-array-2.nll.stderr
index 5b2e1bed0c7bf..20bfdc2bbac72 100644
--- a/src/test/ui/moves/move-into-dead-array-2.nll.stderr
+++ b/src/test/ui/moves/move-into-dead-array-2.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `a`
   --> $DIR/move-into-dead-array-2.rs:14:5
    |
+LL | fn foo(mut a: [D; 4], i: usize) {
+   |        ----- move occurs because `a` has type `[D; 4]`, which does not implement the `Copy` trait
 LL |     drop(a);
    |          - value moved here
 LL |     a[i] = d(); //~ ERROR use of moved value: `a`
    |     ^^^^ value used here after move
-   |
-   = note: move occurs because `a` has type `[D; 4]`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/moves-based-on-type-access-to-field.nll.stderr b/src/test/ui/moves/moves-based-on-type-access-to-field.nll.stderr
index 22968b329695f..6ad9a2d414c77 100644
--- a/src/test/ui/moves/moves-based-on-type-access-to-field.nll.stderr
+++ b/src/test/ui/moves/moves-based-on-type-access-to-field.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-access-to-field.rs:11:12
    |
+LL |     let x = vec!["hi".to_string()];
+   |         - move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 LL |     consume(x.into_iter().next().unwrap());
    |             - value moved here
 LL |     touch(&x[0]); //~ ERROR use of moved value: `x`
    |            ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/moves-based-on-type-capture-clause-bad.nll.stderr b/src/test/ui/moves/moves-based-on-type-capture-clause-bad.nll.stderr
index 061e871c78a73..bed0ae7275cc5 100644
--- a/src/test/ui/moves/moves-based-on-type-capture-clause-bad.nll.stderr
+++ b/src/test/ui/moves/moves-based-on-type-capture-clause-bad.nll.stderr
@@ -1,6 +1,8 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-capture-clause-bad.rs:8:20
    |
+LL |     let x = "Hello world!".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     thread::spawn(move|| {
    |                   ------ value moved into closure here
 LL |         println!("{}", x);
@@ -8,8 +10,6 @@ LL |         println!("{}", x);
 LL |     });
 LL |     println!("{}", x); //~ ERROR use of moved value
    |                    ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/moves/moves-based-on-type-distribute-copy-over-paren.nll.stderr b/src/test/ui/moves/moves-based-on-type-distribute-copy-over-paren.nll.stderr
index 10593a6078e3b..07f40274f9e31 100644
--- a/src/test/ui/moves/moves-based-on-type-distribute-copy-over-paren.nll.stderr
+++ b/src/test/ui/moves/moves-based-on-type-distribute-copy-over-paren.nll.stderr
@@ -1,24 +1,24 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-distribute-copy-over-paren.rs:11:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = Foo { f:x };
    |                      - value moved here
 LL |     //~^ NOTE value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-distribute-copy-over-paren.rs:20:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = Foo { f:(((x))) };
    |                      ------- value moved here
 LL |     //~^ NOTE value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/moves/moves-based-on-type-exprs.nll.stderr b/src/test/ui/moves/moves-based-on-type-exprs.nll.stderr
index fe44803e2734b..162aec45f5f57 100644
--- a/src/test/ui/moves/moves-based-on-type-exprs.nll.stderr
+++ b/src/test/ui/moves/moves-based-on-type-exprs.nll.stderr
@@ -1,117 +1,122 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:12:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = Foo { f:x };
    |                      - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:18:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = (x, 3);
    |               - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:35:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |         x
    |         - value moved here
 ...
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `y`
   --> $DIR/moves-based-on-type-exprs.rs:36:11
    |
+LL |     let y = "ho".to_string();
+   |         - move occurs because `y` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |         y
    |         - value moved here
 ...
 LL |     touch(&y); //~ ERROR use of moved value: `y`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `y` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:46:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |         true => x,
    |                 - value moved here
 ...
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `y`
   --> $DIR/moves-based-on-type-exprs.rs:47:11
    |
+LL |     let y = "ho".to_string();
+   |         - move occurs because `y` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |         false => y
    |                  - value moved here
 ...
 LL |     touch(&y); //~ ERROR use of moved value: `y`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `y` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:58:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |         _ if guard(x) => 10,
    |                    - value moved here
 ...
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:65:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = [x];
    |               - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:71:11
    |
+LL |     let x = "hi".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = vec![x];
    |                   - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:77:11
    |
+LL |     let x = vec!["hi".to_string()];
+   |         - move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 LL |     let _y = x.into_iter().next().unwrap();
    |              - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/moves-based-on-type-exprs.rs:83:11
    |
+LL |     let x = vec!["hi".to_string()];
+   |         - move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 LL |     let _y = [x.into_iter().next().unwrap(); 1];
    |               - value moved here
 LL |     touch(&x); //~ ERROR use of moved value: `x`
    |           ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::vec::Vec<std::string::String>`, which does not implement the `Copy` trait
 
 error: aborting due to 11 previous errors
 
diff --git a/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.nll.stderr b/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.nll.stderr
index 03a23420bbc9e..391dd67dbf60a 100644
--- a/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.nll.stderr
+++ b/src/test/ui/moves/moves-based-on-type-no-recursive-stack-closure.nll.stderr
@@ -10,12 +10,14 @@ LL |                     (f.c)(f, true);
 error[E0382]: borrow of moved value: `f`
   --> $DIR/moves-based-on-type-no-recursive-stack-closure.rs:32:5
    |
+LL | fn conspirator<F>(mut f: F) where F: FnMut(&mut R, bool) {
+   |                -  ----- move occurs because `f` has type `F`, which does not implement the `Copy` trait
+   |                |
+   |                consider adding a `Copy` constraint to this type argument
 LL |     let mut r = R {c: Box::new(f)};
    |                                - value moved here
 LL |     f(&mut r, false) //~ ERROR use of moved value
    |     ^ value borrowed here after move
-   |
-   = note: move occurs because `f` has type `F`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/moves/moves-based-on-type-tuple.stderr b/src/test/ui/moves/moves-based-on-type-tuple.stderr
index 2d2c0a15a002a..c49dbdab40210 100644
--- a/src/test/ui/moves/moves-based-on-type-tuple.stderr
+++ b/src/test/ui/moves/moves-based-on-type-tuple.stderr
@@ -11,12 +11,12 @@ LL |     box (x, x)
 error[E0382]: use of moved value: `x` (Mir)
   --> $DIR/moves-based-on-type-tuple.rs:6:13
    |
+LL | fn dup(x: Box<isize>) -> Box<(Box<isize>,Box<isize>)> {
+   |        - move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 LL |     box (x, x)
    |          -  ^ value used here after move
    |          |
    |          value moved here
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<isize>`, which does not implement the `Copy` trait
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/nested-ty-params.rs b/src/test/ui/nested-ty-params.rs
index 102f8d02ee416..85413acdb1491 100644
--- a/src/test/ui/nested-ty-params.rs
+++ b/src/test/ui/nested-ty-params.rs
@@ -1,4 +1,4 @@
-// error-pattern:can't use type parameters from outer function
+// error-pattern:can't use generic parameters from outer function
 fn hd<U>(v: Vec<U> ) -> U {
     fn hd1(w: [U]) -> U { return w[0]; }
 
diff --git a/src/test/ui/nested-ty-params.stderr b/src/test/ui/nested-ty-params.stderr
index 617eddf6525df..37adeffb9b07a 100644
--- a/src/test/ui/nested-ty-params.stderr
+++ b/src/test/ui/nested-ty-params.stderr
@@ -1,22 +1,22 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/nested-ty-params.rs:3:16
    |
 LL | fn hd<U>(v: Vec<U> ) -> U {
    |       - type variable from outer function
 LL |     fn hd1(w: [U]) -> U { return w[0]; }
-   |        ---     ^ use of type variable from outer function
+   |        ---     ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `hd1<U>`
+   |        help: try using a local generic parameter instead: `hd1<U>`
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/nested-ty-params.rs:3:23
    |
 LL | fn hd<U>(v: Vec<U> ) -> U {
    |       - type variable from outer function
 LL |     fn hd1(w: [U]) -> U { return w[0]; }
-   |        ---            ^ use of type variable from outer function
+   |        ---            ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `hd1<U>`
+   |        help: try using a local generic parameter instead: `hd1<U>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/never-assign-dead-code.stderr b/src/test/ui/never-assign-dead-code.stderr
index c59fd938e8326..bcc20a0d703c0 100644
--- a/src/test/ui/never-assign-dead-code.stderr
+++ b/src/test/ui/never-assign-dead-code.stderr
@@ -21,7 +21,7 @@ warning: unused variable: `x`
   --> $DIR/never-assign-dead-code.rs:9:9
    |
 LL |     let x: ! = panic!("aah"); //~ WARN unused
-   |         ^ help: consider using `_x` instead
+   |         ^ help: consider prefixing with an underscore: `_x`
    |
 note: lint level defined here
   --> $DIR/never-assign-dead-code.rs:5:9
diff --git a/src/test/ui/nll/closure-access-spans.stderr b/src/test/ui/nll/closure-access-spans.stderr
index efe4c15240d20..3ca0aefb592e0 100644
--- a/src/test/ui/nll/closure-access-spans.stderr
+++ b/src/test/ui/nll/closure-access-spans.stderr
@@ -59,50 +59,50 @@ LL |     r.use_ref();
 error[E0382]: borrow of moved value: `x`
   --> $DIR/closure-access-spans.rs:37:5
    |
+LL | fn closure_imm_capture_moved(mut x: String) {
+   |                              ----- move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let r = x;
    |             - value moved here
 LL |     || x.len(); //~ ERROR
    |     ^^ - borrow occurs due to use in closure
    |     |
    |     value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/closure-access-spans.rs:42:5
    |
+LL | fn closure_mut_capture_moved(mut x: String) {
+   |                              ----- move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let r = x;
    |             - value moved here
 LL |     || x = String::new(); //~ ERROR
    |     ^^ - borrow occurs due to use in closure
    |     |
    |     value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/closure-access-spans.rs:47:5
    |
+LL | fn closure_unique_capture_moved(x: &mut String) {
+   |                                 - move occurs because `x` has type `&mut std::string::String`, which does not implement the `Copy` trait
 LL |     let r = x;
    |             - value moved here
 LL |     || *x = String::new(); //~ ERROR
    |     ^^  - borrow occurs due to use in closure
    |     |
    |     value borrowed here after move
-   |
-   = note: move occurs because `x` has type `&mut std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x`
   --> $DIR/closure-access-spans.rs:52:5
    |
+LL | fn closure_move_capture_moved(x: &mut String) {
+   |                               - move occurs because `x` has type `&mut std::string::String`, which does not implement the `Copy` trait
 LL |     let r = x;
    |             - value moved here
 LL |     || x; //~ ERROR
    |     ^^ - use occurs due to use in closure
    |     |
    |     value used here after move
-   |
-   = note: move occurs because `x` has type `&mut std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/nll/closure-move-spans.stderr b/src/test/ui/nll/closure-move-spans.stderr
index 3ae1912eb10bf..6750c4047601a 100644
--- a/src/test/ui/nll/closure-move-spans.stderr
+++ b/src/test/ui/nll/closure-move-spans.stderr
@@ -1,38 +1,38 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/closure-move-spans.rs:7:13
    |
+LL | fn move_after_move(x: String) {
+   |                    - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     || x;
    |     -- - variable moved due to use in closure
    |     |
    |     value moved into closure here
 LL |     let y = x; //~ ERROR
    |             ^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/closure-move-spans.rs:12:13
    |
+LL | fn borrow_after_move(x: String) {
+   |                      - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     || x;
    |     -- - variable moved due to use in closure
    |     |
    |     value moved into closure here
 LL |     let y = &x; //~ ERROR
    |             ^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/closure-move-spans.rs:17:13
    |
+LL | fn borrow_mut_after_move(mut x: String) {
+   |                          ----- move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     || x;
    |     -- - variable moved due to use in closure
    |     |
    |     value moved into closure here
 LL |     let y = &mut x; //~ ERROR
    |             ^^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr b/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
index 66f8791bfcb65..8e407070342cf 100644
--- a/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
+++ b/src/test/ui/nll/closure-requirements/escape-argument-callee.stderr
@@ -9,7 +9,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
                for<'r, 's, 't0> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 'r)) mut &ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 's)) i32, &ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 't0)) i32))
            ]
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/escape-argument-callee.rs:26:45
    |
 LL |         let mut closure = expect_sig(|p, y| *p = y);
diff --git a/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs b/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs
new file mode 100644
index 0000000000000..71d5d4053ee25
--- /dev/null
+++ b/src/test/ui/nll/closure-requirements/issue-58127-mutliple-requirements.rs
@@ -0,0 +1,40 @@
+// revisions: migrate nll
+//[migrate]compile-flags: -Z borrowck=migrate
+#![cfg_attr(nll, feature(nll))]
+
+// compile-pass
+
+// Test that we propagate region relations from closures precisely when there is
+// more than one non-local lower bound.
+
+// In this case the closure has signature
+// |x: &'4 mut (&'5 (&'1 str, &'2 str), &'3 str)| -> ..
+// We end up with a `'3: '5` constraint that we can propagate as
+// `'3: '1`, `'3: '2`, but previously we approximated it as `'3: 'static`.
+
+// As an optimization, we primarily propagate bounds for the "representative"
+// of each SCC. As such we have these two similar cases where hopefully one
+// of them will test the case we want (case2, when this test was added).
+mod case1 {
+    fn f(s: &str) {
+        g(s, |x| h(x));
+    }
+
+    fn g<T, F>(_: T, _: F)
+    where F: Fn(&mut (&(T, T), T)) {}
+
+    fn h<T>(_: &mut (&(T, T), T)) {}
+}
+
+mod case2 {
+    fn f(s: &str) {
+        g(s, |x| h(x));
+    }
+
+    fn g<T, F>(_: T, _: F)
+    where F: Fn(&mut (T, &(T, T))) {}
+
+    fn h<T>(_: &mut (T, &(T, T))) {}
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
index 5594271a21d60..55e4573e60bbb 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
@@ -16,7 +16,7 @@ LL | |         },
    = note: late-bound region is '_#5r
    = note: late-bound region is '_#6r
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/propagate-approximated-fail-no-postdom.rs:46:13
    |
 LL |         |_outlives1, _outlives2, _outlives3, x, y| {
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.rs b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.rs
index 7296bbad5189f..1c409a14b7280 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.rs
@@ -41,10 +41,9 @@ fn demand_y<'x, 'y>(_cell_x: &Cell<&'x u32>, _cell_y: &Cell<&'y u32>, _y: &'y u3
 #[rustc_regions]
 fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-
         // Only works if 'x: 'y:
         demand_y(x, y, x.get())
-        //~^ ERROR unsatisfied lifetime constraints
+        //~^ ERROR lifetime may not live long enough
     });
 }
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
index a827b85318792..5863b9bc84094 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-ref.stderr
@@ -3,10 +3,9 @@ note: External requirements
    |
 LL |       establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
    |  _______________________________________________^
-LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
-LL | |         //~^ ERROR unsatisfied lifetime constraints
+LL | |         //~^ ERROR lifetime may not live long enough
 LL | |     });
    | |_____^
    |
@@ -24,17 +23,17 @@ note: No external requirements
    |
 LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
 LL | |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |
 LL | |         // Only works if 'x: 'y:
-...  |
+LL | |         demand_y(x, y, x.get())
+LL | |         //~^ ERROR lifetime may not live long enough
 LL | |     });
 LL | | }
    | |_^
    |
    = note: defining type: DefId(0/0:6 ~ propagate_approximated_ref[317d]::supply[0]) with substs []
 
-error: unsatisfied lifetime constraints
-  --> $DIR/propagate-approximated-ref.rs:46:9
+error: lifetime may not live long enough
+  --> $DIR/propagate-approximated-ref.rs:45:9
    |
 LL | fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
    |           --  -- lifetime `'b` defined here
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-val.rs b/src/test/ui/nll/closure-requirements/propagate-approximated-val.rs
index eb6159c14e1e2..233a5dcab08ab 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-val.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-val.rs
@@ -34,10 +34,9 @@ fn demand_y<'x, 'y>(_outlives1: Cell<&&'x u32>, _outlives2: Cell<&'y &u32>, _y:
 #[rustc_regions]
 fn test<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
-
         // Only works if 'x: 'y:
         demand_y(outlives1, outlives2, x.get())
-        //~^ ERROR unsatisfied lifetime constraints
+        //~^ ERROR lifetime may not live long enough
     });
 }
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
index 1f9d1d7fb5038..b6d9d8529cf5c 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-val.stderr
@@ -3,10 +3,9 @@ note: External requirements
    |
 LL |       establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
    |  _____________________________________________^
-LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(outlives1, outlives2, x.get())
-LL | |         //~^ ERROR unsatisfied lifetime constraints
+LL | |         //~^ ERROR lifetime may not live long enough
 LL | |     });
    | |_____^
    |
@@ -24,17 +23,17 @@ note: No external requirements
    |
 LL | / fn test<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
 LL | |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
-LL | |
 LL | |         // Only works if 'x: 'y:
-...  |
+LL | |         demand_y(outlives1, outlives2, x.get())
+LL | |         //~^ ERROR lifetime may not live long enough
 LL | |     });
 LL | | }
    | |_^
    |
    = note: defining type: DefId(0/0:6 ~ propagate_approximated_val[317d]::test[0]) with substs []
 
-error: unsatisfied lifetime constraints
-  --> $DIR/propagate-approximated-val.rs:39:9
+error: lifetime may not live long enough
+  --> $DIR/propagate-approximated-val.rs:38:9
    |
 LL | fn test<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
    |         --  -- lifetime `'b` defined here
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
index 1a8988f365d0c..93eb93bdc0638 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
@@ -16,7 +16,7 @@ LL | |     });
    = note: late-bound region is '_#2r
    = note: late-bound region is '_#3r
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-no-bounds.rs:37:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
index d0492bdc573c3..c7809de88b922 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
@@ -16,7 +16,7 @@ LL | |     });
    = note: late-bound region is '_#3r
    = note: late-bound region is '_#4r
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-wrong-bounds.rs:41:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
diff --git a/src/test/ui/nll/closure-requirements/region-lbr-named-does-not-outlive-static.stderr b/src/test/ui/nll/closure-requirements/region-lbr-named-does-not-outlive-static.stderr
index 0bc05922235cf..d0a24a267fd4f 100644
--- a/src/test/ui/nll/closure-requirements/region-lbr-named-does-not-outlive-static.stderr
+++ b/src/test/ui/nll/closure-requirements/region-lbr-named-does-not-outlive-static.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/region-lbr-named-does-not-outlive-static.rs:9:5
    |
 LL | fn foo<'a>(x: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.rs b/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.rs
index 1be27aebb3f0d..4d864c6e58868 100644
--- a/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.rs
+++ b/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.rs
@@ -7,7 +7,7 @@
 
 fn foo<'a, 'b>(x: &'a u32, y: &'b u32) -> &'b u32 {
     &*x
-        //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
-fn main() { }
+fn main() {}
diff --git a/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.stderr b/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.stderr
index 2332332f5b8c0..6dc98a944086f 100644
--- a/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.stderr
+++ b/src/test/ui/nll/closure-requirements/region-lbr1-does-not-outlive-ebr2.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/region-lbr1-does-not-outlive-ebr2.rs:9:5
    |
 LL | fn foo<'a, 'b>(x: &'a u32, y: &'b u32) -> &'b u32 {
diff --git a/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr b/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
index 26243f9b821d3..4a035d0c9cd83 100644
--- a/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
+++ b/src/test/ui/nll/closure-requirements/return-wrong-bound-region.stderr
@@ -9,7 +9,7 @@ LL |     expect_sig(|a, b| b); // ought to return `a`
                for<'r, 's> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 'r)) i32, &ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 's)) i32)) -> &ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 'r)) i32
            ]
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/return-wrong-bound-region.rs:11:23
    |
 LL |     expect_sig(|a, b| b); // ought to return `a`
diff --git a/src/test/ui/nll/closures-in-loops.stderr b/src/test/ui/nll/closures-in-loops.stderr
index 93e095d663cc2..6c9e1639f88dd 100644
--- a/src/test/ui/nll/closures-in-loops.stderr
+++ b/src/test/ui/nll/closures-in-loops.stderr
@@ -1,12 +1,13 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/closures-in-loops.rs:8:9
    |
+LL | fn repreated_move(x: String) {
+   |                   - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
+LL |     for i in 0..10 {
 LL |         || x; //~ ERROR
    |         ^^ - use occurs due to use in closure
    |         |
    |         value moved into closure here, in previous iteration of loop
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0499]: cannot borrow `x` as mutable more than once at a time
   --> $DIR/closures-in-loops.rs:15:16
diff --git a/src/test/ui/nll/issue-21232-partial-init-and-erroneous-use.stderr b/src/test/ui/nll/issue-21232-partial-init-and-erroneous-use.stderr
index e29c44760a987..54c728e3d2783 100644
--- a/src/test/ui/nll/issue-21232-partial-init-and-erroneous-use.stderr
+++ b/src/test/ui/nll/issue-21232-partial-init-and-erroneous-use.stderr
@@ -13,12 +13,12 @@ LL |     d.x = 10;
 error[E0382]: assign of moved value: `d`
   --> $DIR/issue-21232-partial-init-and-erroneous-use.rs:43:5
    |
+LL |     let mut d = D { x: 0, s: S{ y: 0, z: 0 } };
+   |         ----- move occurs because `d` has type `D`, which does not implement the `Copy` trait
 LL |     drop(d);
    |          - value moved here
 LL |     d.x = 10;
    |     ^^^^^^^^ value assigned here after move
-   |
-   = note: move occurs because `d` has type `D`, which does not implement the `Copy` trait
 
 error[E0381]: assign to part of possibly uninitialized variable: `d`
   --> $DIR/issue-21232-partial-init-and-erroneous-use.rs:49:5
@@ -35,12 +35,12 @@ LL |     d.s.y = 20;
 error[E0382]: assign to part of moved value: `d`
   --> $DIR/issue-21232-partial-init-and-erroneous-use.rs:62:5
    |
+LL |     let mut d = D { x: 0, s: S{ y: 0, z: 0} };
+   |         ----- move occurs because `d` has type `D`, which does not implement the `Copy` trait
 LL |     drop(d);
    |          - value moved here
 LL |     d.s.y = 20;
    |     ^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `d` has type `D`, which does not implement the `Copy` trait
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/nll/issue-21232-partial-init-and-use.stderr b/src/test/ui/nll/issue-21232-partial-init-and-use.stderr
index aec7f676fcebd..23da533252cb9 100644
--- a/src/test/ui/nll/issue-21232-partial-init-and-use.stderr
+++ b/src/test/ui/nll/issue-21232-partial-init-and-use.stderr
@@ -14,21 +14,21 @@ error[E0382]: assign to part of moved value: `s`
   --> $DIR/issue-21232-partial-init-and-use.rs:113:5
    |
 LL |     let mut s: S<B> = S::new(); drop(s);
-   |                                      - value moved here
+   |         -----                        - value moved here
+   |         |
+   |         move occurs because `s` has type `S<std::boxed::Box<u32>>`, which does not implement the `Copy` trait
 LL |     s.x = 10; s.y = Box::new(20);
    |     ^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `s` has type `S<std::boxed::Box<u32>>`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-21232-partial-init-and-use.rs:120:5
    |
 LL |     let mut t: T = (0, Box::new(0)); drop(t);
-   |                                           - value moved here
+   |         -----                             - value moved here
+   |         |
+   |         move occurs because `t` has type `(u32, std::boxed::Box<u32>)`, which does not implement the `Copy` trait
 LL |     t.0 = 10; t.1 = Box::new(20);
    |     ^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(u32, std::boxed::Box<u32>)`, which does not implement the `Copy` trait
 
 error[E0381]: assign to part of possibly uninitialized variable: `s`
   --> $DIR/issue-21232-partial-init-and-use.rs:127:5
@@ -46,21 +46,21 @@ error[E0382]: assign to part of moved value: `s`
   --> $DIR/issue-21232-partial-init-and-use.rs:141:5
    |
 LL |     let mut s: S<B> = S::new(); drop(s);
-   |                                      - value moved here
+   |         -----                        - value moved here
+   |         |
+   |         move occurs because `s` has type `S<std::boxed::Box<u32>>`, which does not implement the `Copy` trait
 LL |     s.x = 10;
    |     ^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `s` has type `S<std::boxed::Box<u32>>`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `t`
   --> $DIR/issue-21232-partial-init-and-use.rs:148:5
    |
 LL |     let mut t: T = (0, Box::new(0)); drop(t);
-   |                                           - value moved here
+   |         -----                             - value moved here
+   |         |
+   |         move occurs because `t` has type `(u32, std::boxed::Box<u32>)`, which does not implement the `Copy` trait
 LL |     t.0 = 10;
    |     ^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `t` has type `(u32, std::boxed::Box<u32>)`, which does not implement the `Copy` trait
 
 error[E0381]: assign to part of possibly uninitialized variable: `s`
   --> $DIR/issue-21232-partial-init-and-use.rs:155:5
@@ -153,22 +153,24 @@ LL |     q.r.f.0 = 10;
 error[E0382]: assign to part of moved value: `c`
   --> $DIR/issue-21232-partial-init-and-use.rs:259:13
    |
+LL |     let mut c = (1, "".to_owned());
+   |         ----- move occurs because `c` has type `(i32, std::string::String)`, which does not implement the `Copy` trait
+LL |     match c {
 LL |         c2 => {
    |         -- value moved here
 LL |             c.0 = 2; //~ ERROR assign to part of moved value
    |             ^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `c` has type `(i32, std::string::String)`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `c`
   --> $DIR/issue-21232-partial-init-and-use.rs:269:13
    |
+LL |     let mut c = (1, (1, "".to_owned()));
+   |         ----- move occurs because `c` has type `(i32, (i32, std::string::String))`, which does not implement the `Copy` trait
+LL |     match c {
 LL |         c2 => {
    |         -- value moved here
 LL |             (c.1).0 = 2; //~ ERROR assign to part of moved value
    |             ^^^^^^^^^^^ value partially assigned here after move
-   |
-   = note: move occurs because `c` has type `(i32, (i32, std::string::String))`, which does not implement the `Copy` trait
 
 error[E0382]: assign to part of moved value: `c.1`
   --> $DIR/issue-21232-partial-init-and-use.rs:277:13
diff --git a/src/test/ui/nll/issue-48238.stderr b/src/test/ui/nll/issue-48238.stderr
index 913effa1c93c0..7cb5eb736c0e3 100644
--- a/src/test/ui/nll/issue-48238.stderr
+++ b/src/test/ui/nll/issue-48238.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-48238.rs:11:13
    |
 LL |     move || use_val(&orig); //~ ERROR
diff --git a/src/test/ui/nll/issue-50716.stderr b/src/test/ui/nll/issue-50716.stderr
index fa893df3e15ad..229bb1777cc5e 100644
--- a/src/test/ui/nll/issue-50716.stderr
+++ b/src/test/ui/nll/issue-50716.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-50716.rs:16:14
    |
 LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
diff --git a/src/test/ui/nll/issue-51512.stderr b/src/test/ui/nll/issue-51512.stderr
index 4717935e4b9f9..a84a236ca7772 100644
--- a/src/test/ui/nll/issue-51512.stderr
+++ b/src/test/ui/nll/issue-51512.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `range`
   --> $DIR/issue-51512.rs:7:13
    |
+LL |     let range = 0..1;
+   |         ----- move occurs because `range` has type `std::ops::Range<i32>`, which does not implement the `Copy` trait
 LL |     let r = range;
    |             ----- value moved here
 LL |     let x = range.start;
    |             ^^^^^^^^^^^ value used here after move
-   |
-   = note: move occurs because `range` has type `std::ops::Range<i32>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/nll/issue-52113.rs b/src/test/ui/nll/issue-52113.rs
index 8428e55eeb65b..795f4f426ffff 100644
--- a/src/test/ui/nll/issue-52113.rs
+++ b/src/test/ui/nll/issue-52113.rs
@@ -3,8 +3,8 @@
 #![allow(warnings)]
 #![feature(nll)]
 
-trait Bazinga { }
-impl<F> Bazinga for F { }
+trait Bazinga {}
+impl<F> Bazinga for F {}
 
 fn produce1<'a>(data: &'a u32) -> impl Bazinga + 'a {
     let x = move || {
@@ -21,7 +21,6 @@ fn produce2<'a>(data: &'a mut Vec<&'a u32>, value: &'a u32) -> impl Bazinga + 'a
     x
 }
 
-
 fn produce3<'a, 'b: 'a>(data: &'a mut Vec<&'a u32>, value: &'b u32) -> impl Bazinga + 'a {
     let x = move || {
         let value: &'a u32 = value;
@@ -35,7 +34,7 @@ fn produce_err<'a, 'b: 'a>(data: &'b mut Vec<&'b u32>, value: &'a u32) -> impl B
         let value: &'a u32 = value;
         data.push(value);
     };
-    x   //~ ERROR unsatisfied lifetime constraints
+    x //~ ERROR lifetime may not live long enough
 }
 
-fn main() { }
+fn main() {}
diff --git a/src/test/ui/nll/issue-52113.stderr b/src/test/ui/nll/issue-52113.stderr
index 873612d7657d6..ceae16185bbb1 100644
--- a/src/test/ui/nll/issue-52113.stderr
+++ b/src/test/ui/nll/issue-52113.stderr
@@ -1,12 +1,12 @@
-error: unsatisfied lifetime constraints
-  --> $DIR/issue-52113.rs:38:5
+error: lifetime may not live long enough
+  --> $DIR/issue-52113.rs:37:5
    |
 LL | fn produce_err<'a, 'b: 'a>(data: &'b mut Vec<&'b u32>, value: &'a u32) -> impl Bazinga + 'b {
    |                --  -- lifetime `'b` defined here
    |                |
    |                lifetime `'a` defined here
 ...
-LL |     x   //~ ERROR unsatisfied lifetime constraints
+LL |     x //~ ERROR lifetime may not live long enough
    |     ^ returning this value requires that `'a` must outlive `'b`
 
 error: aborting due to previous error
diff --git a/src/test/ui/nll/issue-52669.stderr b/src/test/ui/nll/issue-52669.stderr
index e1fb76c6bc242..f51768c3859e4 100644
--- a/src/test/ui/nll/issue-52669.stderr
+++ b/src/test/ui/nll/issue-52669.stderr
@@ -1,12 +1,13 @@
 error[E0382]: borrow of moved value: `a.b`
   --> $DIR/issue-52669.rs:15:5
    |
+LL | fn bar(mut a: A) -> B {
+   |        ----- move occurs because `a` has type `A`, which does not implement the `Copy` trait
+LL |     a.b = B;
 LL |     foo(a);
    |         - value moved here
 LL |     a.b.clone()
    |     ^^^ value borrowed here after move
-   |
-   = note: move occurs because `a` has type `A`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/nll/issue-52742.rs b/src/test/ui/nll/issue-52742.rs
index d8251cb20640a..150e67fe09481 100644
--- a/src/test/ui/nll/issue-52742.rs
+++ b/src/test/ui/nll/issue-52742.rs
@@ -7,14 +7,14 @@ struct Foo<'a, 'b> {
 }
 
 struct Bar<'b> {
-    z: &'b u32
+    z: &'b u32,
 }
 
 impl Foo<'_, '_> {
     fn take_bar(&mut self, b: Bar<'_>) {
         self.y = b.z
-        //~^ ERROR unsatisfied lifetime constraints
+        //~^ ERROR lifetime may not live long enough
     }
 }
 
-fn main() { }
+fn main() {}
diff --git a/src/test/ui/nll/issue-52742.stderr b/src/test/ui/nll/issue-52742.stderr
index f733702cd8b4b..6b25296c4bda1 100644
--- a/src/test/ui/nll/issue-52742.stderr
+++ b/src/test/ui/nll/issue-52742.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-52742.rs:15:9
    |
 LL |     fn take_bar(&mut self, b: Bar<'_>) {
diff --git a/src/test/ui/nll/issue-53773.rs b/src/test/ui/nll/issue-53773.rs
new file mode 100644
index 0000000000000..62e1631dcf36f
--- /dev/null
+++ b/src/test/ui/nll/issue-53773.rs
@@ -0,0 +1,49 @@
+#![feature(nll)]
+
+struct Archive;
+struct ArchiveIterator<'a> {
+    x: &'a Archive,
+}
+struct ArchiveChild<'a> {
+    x: &'a Archive,
+}
+
+struct A {
+    raw: &'static mut Archive,
+}
+struct Iter<'a> {
+    raw: &'a mut ArchiveIterator<'a>,
+}
+struct C<'a> {
+    raw: &'a mut ArchiveChild<'a>,
+}
+
+impl A {
+    pub fn iter(&self) -> Iter<'_> {
+        panic!()
+    }
+}
+impl Drop for A {
+    fn drop(&mut self) {}
+}
+impl<'a> Drop for C<'a> {
+    fn drop(&mut self) {}
+}
+
+impl<'a> Iterator for Iter<'a> {
+    type Item = C<'a>;
+    fn next(&mut self) -> Option<C<'a>> {
+        panic!()
+    }
+}
+
+fn error(archive: &A) {
+    let mut members: Vec<&mut ArchiveChild<'_>> = vec![];
+    for child in archive.iter() {
+        members.push(child.raw);
+        //~^ ERROR borrow may still be in use when destructor runs [E0713]
+    }
+    members.len();
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-53773.stderr b/src/test/ui/nll/issue-53773.stderr
new file mode 100644
index 0000000000000..92a9946068cfe
--- /dev/null
+++ b/src/test/ui/nll/issue-53773.stderr
@@ -0,0 +1,16 @@
+error[E0713]: borrow may still be in use when destructor runs
+  --> $DIR/issue-53773.rs:43:22
+   |
+LL |         members.push(child.raw);
+   |                      ^^^^^^^^^
+LL |         //~^ ERROR borrow may still be in use when destructor runs [E0713]
+LL |     }
+   |     - here, drop of `child` needs exclusive access to `*child.raw`, because the type `C<'_>` implements the `Drop` trait
+LL |     members.len();
+   |     ------- borrow later used here
+   |
+   = note: consider using a `let` binding to create a longer lived value
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0713`.
diff --git a/src/test/ui/nll/issue-55394.rs b/src/test/ui/nll/issue-55394.rs
index 4a83c33239c19..deb1034525edb 100644
--- a/src/test/ui/nll/issue-55394.rs
+++ b/src/test/ui/nll/issue-55394.rs
@@ -8,7 +8,7 @@ struct Foo<'s> {
 
 impl Foo<'_> {
     fn new(bar: &mut Bar) -> Self {
-        Foo { bar } //~ ERROR unsatisfied lifetime constraints
+        Foo { bar } //~ERROR lifetime may not live long enough
     }
 }
 
diff --git a/src/test/ui/nll/issue-55394.stderr b/src/test/ui/nll/issue-55394.stderr
index a4c5160c7b326..bcdd78248eb4b 100644
--- a/src/test/ui/nll/issue-55394.stderr
+++ b/src/test/ui/nll/issue-55394.stderr
@@ -1,11 +1,11 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-55394.rs:11:9
    |
 LL |     fn new(bar: &mut Bar) -> Self {
    |                 -            ---- return type is Foo<'2>
    |                 |
    |                 let's call the lifetime of this reference `'1`
-LL |         Foo { bar } //~ ERROR unsatisfied lifetime constraints
+LL |         Foo { bar } //~ERROR lifetime may not live long enough
    |         ^^^^^^^^^^^ returning this value requires that `'1` must outlive `'2`
 
 error: aborting due to previous error
diff --git a/src/test/ui/nll/issue-55401.stderr b/src/test/ui/nll/issue-55401.stderr
index 9e50db7b6045d..952b5441f86ff 100644
--- a/src/test/ui/nll/issue-55401.stderr
+++ b/src/test/ui/nll/issue-55401.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-55401.rs:5:5
    |
 LL | fn static_to_a_to_static_through_ref_in_tuple<'a>(x: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/issue-55850.rs b/src/test/ui/nll/issue-55850.rs
index eafbfd21700c8..8b5887224d19a 100644
--- a/src/test/ui/nll/issue-55850.rs
+++ b/src/test/ui/nll/issue-55850.rs
@@ -1,23 +1,23 @@
 #![allow(unused_mut)]
 #![feature(generators, generator_trait)]
 
+use std::marker::Unpin;
 use std::ops::Generator;
 use std::ops::GeneratorState::Yielded;
+use std::pin::Pin;
 
 pub struct GenIter<G>(G);
 
 impl <G> Iterator for GenIter<G>
 where
-    G: Generator,
+    G: Generator + Unpin,
 {
     type Item = G::Yield;
 
     fn next(&mut self) -> Option<Self::Item> {
-        unsafe {
-            match self.0.resume() {
-                Yielded(y) => Some(y),
-                _ => None
-            }
+        match Pin::new(&mut self.0).resume() {
+            Yielded(y) => Some(y),
+            _ => None
         }
     }
 }
diff --git a/src/test/ui/nll/issue-57960.rs b/src/test/ui/nll/issue-57960.rs
new file mode 100644
index 0000000000000..0b52e46c45989
--- /dev/null
+++ b/src/test/ui/nll/issue-57960.rs
@@ -0,0 +1,39 @@
+// run-pass
+
+#![allow(dead_code)]
+
+trait Range {
+    const FIRST: u8;
+    const LAST: u8;
+}
+
+struct OneDigit;
+impl Range for OneDigit {
+    const FIRST: u8 = 0;
+    const LAST: u8 = 9;
+}
+
+struct TwoDigits;
+impl Range for TwoDigits {
+    const FIRST: u8 = 10;
+    const LAST: u8 = 99;
+}
+
+struct ThreeDigits;
+impl Range for ThreeDigits {
+    const FIRST: u8 = 100;
+    const LAST: u8 = 255;
+}
+
+fn digits(x: u8) -> u32 {
+    match x {
+        OneDigit::FIRST...OneDigit::LAST => 1,
+        TwoDigits::FIRST...TwoDigits::LAST => 2,
+        ThreeDigits::FIRST...ThreeDigits::LAST => 3,
+        _ => unreachable!(),
+    }
+}
+
+fn main() {
+    assert_eq!(digits(100), 3);
+}
diff --git a/src/test/ui/nll/issue-57989.rs b/src/test/ui/nll/issue-57989.rs
new file mode 100644
index 0000000000000..4f21cca97cc09
--- /dev/null
+++ b/src/test/ui/nll/issue-57989.rs
@@ -0,0 +1,12 @@
+// Test for ICE from issue 57989
+
+#![feature(nll)]
+
+fn f(x: &i32) {
+    let g = &x;
+    *x = 0;     //~ ERROR cannot assign to `*x` which is behind a `&` reference
+                //~| ERROR cannot assign to `*x` because it is borrowed
+    g;
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-57989.stderr b/src/test/ui/nll/issue-57989.stderr
new file mode 100644
index 0000000000000..4561c99096f14
--- /dev/null
+++ b/src/test/ui/nll/issue-57989.stderr
@@ -0,0 +1,24 @@
+error[E0594]: cannot assign to `*x` which is behind a `&` reference
+  --> $DIR/issue-57989.rs:7:5
+   |
+LL | fn f(x: &i32) {
+   |         ---- help: consider changing this to be a mutable reference: `&mut i32`
+LL |     let g = &x;
+LL |     *x = 0;     //~ ERROR cannot assign to `*x` which is behind a `&` reference
+   |     ^^^^^^ `x` is a `&` reference, so the data it refers to cannot be written
+
+error[E0506]: cannot assign to `*x` because it is borrowed
+  --> $DIR/issue-57989.rs:7:5
+   |
+LL |     let g = &x;
+   |             -- borrow of `*x` occurs here
+LL |     *x = 0;     //~ ERROR cannot assign to `*x` which is behind a `&` reference
+   |     ^^^^^^ assignment to borrowed `*x` occurs here
+LL |                 //~| ERROR cannot assign to `*x` because it is borrowed
+LL |     g;
+   |     - borrow later used here
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0506, E0594.
+For more information about an error, try `rustc --explain E0506`.
diff --git a/src/test/ui/nll/issue-58053.rs b/src/test/ui/nll/issue-58053.rs
new file mode 100644
index 0000000000000..d4338905ed2df
--- /dev/null
+++ b/src/test/ui/nll/issue-58053.rs
@@ -0,0 +1,14 @@
+#![allow(warnings)]
+#![feature(nll)]
+
+fn main() {
+    let i = &3;
+
+    let f = |x: &i32| -> &i32 { x };
+    //~^ ERROR lifetime may not live long enough
+    let j = f(i);
+
+    let g = |x: &i32| { x };
+    //~^ ERROR lifetime may not live long enough
+    let k = g(i);
+}
diff --git a/src/test/ui/nll/issue-58053.stderr b/src/test/ui/nll/issue-58053.stderr
new file mode 100644
index 0000000000000..9048983318b36
--- /dev/null
+++ b/src/test/ui/nll/issue-58053.stderr
@@ -0,0 +1,20 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-58053.rs:7:33
+   |
+LL |     let f = |x: &i32| -> &i32 { x };
+   |                 -        ----   ^ returning this value requires that `'1` must outlive `'2`
+   |                 |        |
+   |                 |        return type of closure is &'2 i32
+   |                 let's call the lifetime of this reference `'1`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-58053.rs:11:25
+   |
+LL |     let g = |x: &i32| { x };
+   |                 -   -   ^ returning this value requires that `'1` must outlive `'2`
+   |                 |   |
+   |                 |   return type of closure is &'2 i32
+   |                 let's call the lifetime of this reference `'1`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/nll/issue-58299.rs b/src/test/ui/nll/issue-58299.rs
new file mode 100644
index 0000000000000..9267cac5dd3d7
--- /dev/null
+++ b/src/test/ui/nll/issue-58299.rs
@@ -0,0 +1,30 @@
+#![allow(dead_code)]
+#![feature(nll)]
+
+struct A<'a>(&'a ());
+
+trait Y {
+    const X: i32;
+}
+
+impl Y for A<'static> {
+    const X: i32 = 10;
+}
+
+fn foo<'a>(x: i32) {
+    match x {
+        // This uses <A<'a> as Y>::X, but `A<'a>` does not implement `Y`.
+        A::<'a>::X..=A::<'static>::X => (), //~ ERROR lifetime may not live long enough
+        _ => (),
+    }
+}
+
+fn bar<'a>(x: i32) {
+    match x {
+        // This uses <A<'a> as Y>::X, but `A<'a>` does not implement `Y`.
+        A::<'static>::X..=A::<'a>::X => (), //~ ERROR lifetime may not live long enough
+        _ => (),
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/issue-58299.stderr b/src/test/ui/nll/issue-58299.stderr
new file mode 100644
index 0000000000000..b87d0de51a37e
--- /dev/null
+++ b/src/test/ui/nll/issue-58299.stderr
@@ -0,0 +1,20 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-58299.rs:17:9
+   |
+LL | fn foo<'a>(x: i32) {
+   |        -- lifetime `'a` defined here
+...
+LL |         A::<'a>::X..=A::<'static>::X => (), //~ ERROR lifetime may not live long enough
+   |         ^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-58299.rs:25:27
+   |
+LL | fn bar<'a>(x: i32) {
+   |        -- lifetime `'a` defined here
+...
+LL |         A::<'static>::X..=A::<'a>::X => (), //~ ERROR lifetime may not live long enough
+   |                           ^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/nll/mir_check_cast_closure.rs b/src/test/ui/nll/mir_check_cast_closure.rs
index 5298e840defd5..0619ff37d972b 100644
--- a/src/test/ui/nll/mir_check_cast_closure.rs
+++ b/src/test/ui/nll/mir_check_cast_closure.rs
@@ -5,7 +5,7 @@
 fn bar<'a, 'b>() -> fn(&'a u32, &'b u32) -> &'a u32 {
     let g: fn(_, _) -> _ = |_x, y| y;
     g
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/mir_check_cast_closure.stderr b/src/test/ui/nll/mir_check_cast_closure.stderr
index b88353371dfbc..e14cb074c81f8 100644
--- a/src/test/ui/nll/mir_check_cast_closure.stderr
+++ b/src/test/ui/nll/mir_check_cast_closure.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/mir_check_cast_closure.rs:7:5
    |
 LL | fn bar<'a, 'b>() -> fn(&'a u32, &'b u32) -> &'a u32 {
diff --git a/src/test/ui/nll/mir_check_cast_reify.rs b/src/test/ui/nll/mir_check_cast_reify.rs
index b0ad8e34b17b5..be12e313b42e6 100644
--- a/src/test/ui/nll/mir_check_cast_reify.rs
+++ b/src/test/ui/nll/mir_check_cast_reify.rs
@@ -35,7 +35,7 @@ fn bar<'a>(x: &'a u32) -> &'static u32 {
     // as part of checking the `ReifyFnPointer`.
     let f: fn(_) -> _ = foo;
     f(x)
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/mir_check_cast_reify.stderr b/src/test/ui/nll/mir_check_cast_reify.stderr
index 2585486f12702..4e8eec330a579 100644
--- a/src/test/ui/nll/mir_check_cast_reify.stderr
+++ b/src/test/ui/nll/mir_check_cast_reify.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/mir_check_cast_reify.rs:37:5
    |
 LL | fn bar<'a>(x: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/mir_check_cast_unsafe_fn.rs b/src/test/ui/nll/mir_check_cast_unsafe_fn.rs
index 29fbf462b30a9..9df9c05748924 100644
--- a/src/test/ui/nll/mir_check_cast_unsafe_fn.rs
+++ b/src/test/ui/nll/mir_check_cast_unsafe_fn.rs
@@ -7,7 +7,7 @@ fn bar<'a>(input: &'a u32, f: fn(&'a u32) -> &'a u32) -> &'static u32 {
     // in `g`. These are related via the `UnsafeFnPointer` cast.
     let g: unsafe fn(_) -> _ = f;
     unsafe { g(input) }
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/mir_check_cast_unsafe_fn.stderr b/src/test/ui/nll/mir_check_cast_unsafe_fn.stderr
index e7b945a51caaf..52959850a3332 100644
--- a/src/test/ui/nll/mir_check_cast_unsafe_fn.stderr
+++ b/src/test/ui/nll/mir_check_cast_unsafe_fn.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/mir_check_cast_unsafe_fn.rs:9:14
    |
 LL | fn bar<'a>(input: &'a u32, f: fn(&'a u32) -> &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/mir_check_cast_unsize.rs b/src/test/ui/nll/mir_check_cast_unsize.rs
index e98d5e14fca62..d15c4e4f46722 100644
--- a/src/test/ui/nll/mir_check_cast_unsize.rs
+++ b/src/test/ui/nll/mir_check_cast_unsize.rs
@@ -6,7 +6,7 @@ use std::fmt::Debug;
 
 fn bar<'a>(x: &'a u32) -> &'static dyn Debug {
     x
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/mir_check_cast_unsize.stderr b/src/test/ui/nll/mir_check_cast_unsize.stderr
index 189bb2dff5275..364d6c17ea7f6 100644
--- a/src/test/ui/nll/mir_check_cast_unsize.stderr
+++ b/src/test/ui/nll/mir_check_cast_unsize.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/mir_check_cast_unsize.rs:8:5
    |
 LL | fn bar<'a>(x: &'a u32) -> &'static dyn Debug {
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
index f2bfdaecdaf27..e8283d1ab5da2 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
@@ -40,7 +40,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |
    = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0/0:8 ~ projection_one_region_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`...
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/projection-one-region-closure.rs:45:39
    |
 LL | fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
@@ -94,7 +94,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |
    = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/projection-one-region-closure.rs:56:39
    |
 LL | fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
index fc59100d1873a..78a8c803dd972 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
@@ -31,7 +31,7 @@ LL | | }
                T
            ]
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/projection-one-region-trait-bound-closure.rs:37:39
    |
 LL | fn no_relationships_late<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
@@ -76,7 +76,7 @@ LL | | }
                T
            ]
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/projection-one-region-trait-bound-closure.rs:47:39
    |
 LL | fn no_relationships_early<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
index 25877e6665c40..20edfb33931af 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
@@ -85,7 +85,7 @@ where
     T: Anything<'b, 'b>,
 {
     with_signature(cell, t, |cell, t| require(cell, t));
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 #[rustc_regions]
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
index c2b54b610fffa..d8725dc4284f3 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
@@ -217,7 +217,7 @@ LL | | where
 LL | |     T: Anything<'b, 'b>,
 LL | | {
 LL | |     with_signature(cell, t, |cell, t| require(cell, t));
-LL | |     //~^ ERROR unsatisfied lifetime constraints
+LL | |     //~^ ERROR lifetime may not live long enough
 LL | | }
    | |_^
    |
@@ -226,7 +226,7 @@ LL | | }
                T
            ]
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/projection-two-region-trait-bound-closure.rs:87:29
    |
 LL | fn two_regions<'a, 'b, T>(cell: Cell<&'a ()>, t: T)
diff --git a/src/test/ui/nll/ty-outlives/projection-where-clause-env-wrong-bound.stderr b/src/test/ui/nll/ty-outlives/projection-where-clause-env-wrong-bound.stderr
index acb978b5d5a2c..597b096dbe607 100644
--- a/src/test/ui/nll/ty-outlives/projection-where-clause-env-wrong-bound.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-where-clause-env-wrong-bound.stderr
@@ -2,7 +2,7 @@ error[E0309]: the associated type `<T as MyTrait<'_>>::Output` may not live long
   --> $DIR/projection-where-clause-env-wrong-bound.rs:17:5
    |
 LL |     bar::<T::Output>() //~ ERROR may not live long enough
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^
    |
    = help: consider adding an explicit lifetime bound `<T as MyTrait<'_>>::Output: 'a`...
 
diff --git a/src/test/ui/nll/ty-outlives/projection-where-clause-none.stderr b/src/test/ui/nll/ty-outlives/projection-where-clause-none.stderr
index 2d171a98789f8..3c2ac474778f9 100644
--- a/src/test/ui/nll/ty-outlives/projection-where-clause-none.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-where-clause-none.stderr
@@ -2,7 +2,7 @@ error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/projection-where-clause-none.rs:16:5
    |
 LL |     bar::<T::Output>() //~ ERROR the parameter type `T` may not live long enough
-   |     ^^^^^^^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^^^^^
    |
    = help: consider adding an explicit lifetime bound `T: 'a`...
 
diff --git a/src/test/ui/nll/ty-outlives/wf-unreachable.rs b/src/test/ui/nll/ty-outlives/wf-unreachable.rs
new file mode 100644
index 0000000000000..a2e3ab41614f6
--- /dev/null
+++ b/src/test/ui/nll/ty-outlives/wf-unreachable.rs
@@ -0,0 +1,54 @@
+// Test that we check that user type annotations are well-formed, even in dead
+// code.
+
+#![feature(nll)]
+
+fn uninit<'a>() {
+    return;
+    let x: &'static &'a ();                         //~ ERROR lifetime may not live long enough
+}
+
+fn var_type<'a>() {
+    return;
+    let x: &'static &'a () = &&();                  //~ ERROR lifetime may not live long enough
+}
+
+fn uninit_infer<'a>() {
+    let x: &'static &'a _;                          //~ ERROR lifetime may not live long enough
+    x = && ();
+}
+
+fn infer<'a>() {
+    return;
+    let x: &'static &'a _ = &&();                   //~ ERROR lifetime may not live long enough
+}
+
+fn uninit_no_var<'a>() {
+    return;
+    let _: &'static &'a ();                         //~ ERROR lifetime may not live long enough
+}
+
+fn no_var<'a>() {
+    return;
+    let _: &'static &'a () = &&();                  //~ ERROR lifetime may not live long enough
+}
+
+fn infer_no_var<'a>() {
+    return;
+    let _: &'static &'a _ = &&();                   //~ ERROR lifetime may not live long enough
+}
+
+trait X<'a, 'b> {}
+
+struct C<'a, 'b, T: X<'a, 'b>>(T, &'a (), &'b ());
+
+impl X<'_, '_> for i32 {}
+impl<'a> X<'a, 'a> for () {}
+
+// This type annotation is not well-formed because we substitute `()` for `_`.
+fn required_substs<'a>() {
+    return;
+    let _: C<'static, 'a, _> = C((), &(), &());     //~ ERROR lifetime may not live long enough
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/ty-outlives/wf-unreachable.stderr b/src/test/ui/nll/ty-outlives/wf-unreachable.stderr
new file mode 100644
index 0000000000000..14642a1e615df
--- /dev/null
+++ b/src/test/ui/nll/ty-outlives/wf-unreachable.stderr
@@ -0,0 +1,73 @@
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:8:12
+   |
+LL | fn uninit<'a>() {
+   |           -- lifetime `'a` defined here
+LL |     return;
+LL |     let x: &'static &'a ();                         //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:13:12
+   |
+LL | fn var_type<'a>() {
+   |             -- lifetime `'a` defined here
+LL |     return;
+LL |     let x: &'static &'a () = &&();                  //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:17:12
+   |
+LL | fn uninit_infer<'a>() {
+   |                 -- lifetime `'a` defined here
+LL |     let x: &'static &'a _;                          //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:23:12
+   |
+LL | fn infer<'a>() {
+   |          -- lifetime `'a` defined here
+LL |     return;
+LL |     let x: &'static &'a _ = &&();                   //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:28:12
+   |
+LL | fn uninit_no_var<'a>() {
+   |                  -- lifetime `'a` defined here
+LL |     return;
+LL |     let _: &'static &'a ();                         //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:33:12
+   |
+LL | fn no_var<'a>() {
+   |           -- lifetime `'a` defined here
+LL |     return;
+LL |     let _: &'static &'a () = &&();                  //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:38:12
+   |
+LL | fn infer_no_var<'a>() {
+   |                 -- lifetime `'a` defined here
+LL |     return;
+LL |     let _: &'static &'a _ = &&();                   //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/wf-unreachable.rs:51:12
+   |
+LL | fn required_substs<'a>() {
+   |                    -- lifetime `'a` defined here
+LL |     return;
+LL |     let _: C<'static, 'a, _> = C((), &(), &());     //~ ERROR lifetime may not live long enough
+   |            ^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
+
+error: aborting due to 8 previous errors
+
diff --git a/src/test/ui/nll/type-alias-free-regions.stderr b/src/test/ui/nll/type-alias-free-regions.stderr
index 6b3bb60d51d3b..bcd141bb406b1 100644
--- a/src/test/ui/nll/type-alias-free-regions.stderr
+++ b/src/test/ui/nll/type-alias-free-regions.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/type-alias-free-regions.rs:19:9
    |
 LL | impl<'a> FromBox<'a> for C<'a> {
@@ -8,7 +8,7 @@ LL |     fn from_box(b: Box<B>) -> Self {
 LL |         C { f: b } //~ ERROR
    |         ^^^^^^^^^^ returning this value requires that `'1` must outlive `'a`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/type-alias-free-regions.rs:29:9
    |
 LL | impl<'a> FromTuple<'a> for C<'a> {
diff --git a/src/test/ui/nll/user-annotations/closure-substs.rs b/src/test/ui/nll/user-annotations/closure-substs.rs
index 9dc84aa0ba7b5..cafdd9257fdc0 100644
--- a/src/test/ui/nll/user-annotations/closure-substs.rs
+++ b/src/test/ui/nll/user-annotations/closure-substs.rs
@@ -5,21 +5,21 @@
 fn foo<'a>() {
     // Here `x` is free in the closure sig:
     |x: &'a i32| -> &'static i32 {
-        return x; //~ ERROR unsatisfied lifetime constraints
+        return x; //~ ERROR lifetime may not live long enough
     };
 }
 
 fn foo1() {
     // Here `x` is bound in the closure sig:
     |x: &i32| -> &'static i32 {
-        return x; //~ ERROR unsatisfied lifetime constraints
+        return x; //~ ERROR lifetime may not live long enough
     };
 }
 
 fn bar<'a>() {
     // Here `x` is free in the closure sig:
     |x: &'a i32, b: fn(&'static i32)| {
-        b(x); //~ ERROR unsatisfied lifetime constraints
+        b(x); //~ ERROR lifetime may not live long enough
     };
 }
 
@@ -30,4 +30,4 @@ fn bar1() {
     };
 }
 
-fn main() { }
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/closure-substs.stderr b/src/test/ui/nll/user-annotations/closure-substs.stderr
index ffc6e5a275705..a46ab61418efb 100644
--- a/src/test/ui/nll/user-annotations/closure-substs.stderr
+++ b/src/test/ui/nll/user-annotations/closure-substs.stderr
@@ -1,27 +1,27 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/closure-substs.rs:8:16
    |
 LL | fn foo<'a>() {
    |        -- lifetime `'a` defined here
 ...
-LL |         return x; //~ ERROR unsatisfied lifetime constraints
+LL |         return x; //~ ERROR lifetime may not live long enough
    |                ^ returning this value requires that `'a` must outlive `'static`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/closure-substs.rs:15:16
    |
 LL |     |x: &i32| -> &'static i32 {
    |         - let's call the lifetime of this reference `'1`
-LL |         return x; //~ ERROR unsatisfied lifetime constraints
+LL |         return x; //~ ERROR lifetime may not live long enough
    |                ^ returning this value requires that `'1` must outlive `'static`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/closure-substs.rs:22:9
    |
 LL | fn bar<'a>() {
    |        -- lifetime `'a` defined here
 ...
-LL |         b(x); //~ ERROR unsatisfied lifetime constraints
+LL |         b(x); //~ ERROR lifetime may not live long enough
    |         ^^^^ argument requires that `'a` must outlive `'static`
 
 error[E0521]: borrowed data escapes outside of closure
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
index 94fbe01772412..541a7113ec740 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-1.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/constant-in-expr-inherent-1.rs:10:5
    |
 LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.rs b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.rs
new file mode 100644
index 0000000000000..123be6b3e4098
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.rs
@@ -0,0 +1,29 @@
+// Test that we still check constants are well-formed, even when we there's no
+// type annotation to check.
+
+#![feature(nll)]
+
+const FUN: fn(&'static ()) = |_| {};
+struct A;
+impl A {
+    const ASSOCIATED_FUN: fn(&'static ()) = |_| {};
+}
+
+struct B<'a>(&'a ());
+impl B<'static> {
+    const ALSO_ASSOCIATED_FUN: fn(&'static ()) = |_| {};
+}
+
+trait Z: 'static {
+    const TRAIT_ASSOCIATED_FUN: fn(&'static Self) = |_| ();
+}
+
+impl Z for () {}
+
+fn main() {
+    let x = ();
+    FUN(&x);                        //~ ERROR `x` does not live long enough
+    A::ASSOCIATED_FUN(&x);          //~ ERROR `x` does not live long enough
+    B::ALSO_ASSOCIATED_FUN(&x);     //~ ERROR `x` does not live long enough
+    <_>::TRAIT_ASSOCIATED_FUN(&x);  //~ ERROR `x` does not live long enough
+}
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.stderr
new file mode 100644
index 0000000000000..57cfaa2db0432
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-inherent-2.stderr
@@ -0,0 +1,50 @@
+error[E0597]: `x` does not live long enough
+  --> $DIR/constant-in-expr-inherent-2.rs:25:9
+   |
+LL |     FUN(&x);                        //~ ERROR `x` does not live long enough
+   |     ----^^-
+   |     |   |
+   |     |   borrowed value does not live long enough
+   |     argument requires that `x` is borrowed for `'static`
+...
+LL | }
+   | - `x` dropped here while still borrowed
+
+error[E0597]: `x` does not live long enough
+  --> $DIR/constant-in-expr-inherent-2.rs:26:23
+   |
+LL |     A::ASSOCIATED_FUN(&x);          //~ ERROR `x` does not live long enough
+   |     ------------------^^-
+   |     |                 |
+   |     |                 borrowed value does not live long enough
+   |     argument requires that `x` is borrowed for `'static`
+...
+LL | }
+   | - `x` dropped here while still borrowed
+
+error[E0597]: `x` does not live long enough
+  --> $DIR/constant-in-expr-inherent-2.rs:27:28
+   |
+LL |     B::ALSO_ASSOCIATED_FUN(&x);     //~ ERROR `x` does not live long enough
+   |     -----------------------^^-
+   |     |                      |
+   |     |                      borrowed value does not live long enough
+   |     argument requires that `x` is borrowed for `'static`
+LL |     <_>::TRAIT_ASSOCIATED_FUN(&x);  //~ ERROR `x` does not live long enough
+LL | }
+   | - `x` dropped here while still borrowed
+
+error[E0597]: `x` does not live long enough
+  --> $DIR/constant-in-expr-inherent-2.rs:28:31
+   |
+LL |     <_>::TRAIT_ASSOCIATED_FUN(&x);  //~ ERROR `x` does not live long enough
+   |     --------------------------^^-
+   |     |                         |
+   |     |                         borrowed value does not live long enough
+   |     argument requires that `x` is borrowed for `'static`
+LL | }
+   | - `x` dropped here while still borrowed
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
index 7aeb276eeb929..5b97c12b626b3 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/constant-in-expr-normalize.rs:20:5
    |
 LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
index fee9abc1ed83a..10e48b5bc348b 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/constant-in-expr-trait-item-1.rs:12:5
    |
 LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
index 047aad9831923..5bfa32ec64492 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/constant-in-expr-trait-item-2.rs:12:5
    |
 LL | fn foo<'a, T: Foo<'a>>() -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-3.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-3.stderr
index b373cebacb063..a1e60db05d08f 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-3.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-3.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/constant-in-expr-trait-item-3.rs:12:5
    |
 LL | fn foo<'a, T: Foo<'a>>() -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/downcast-infer.rs b/src/test/ui/nll/user-annotations/downcast-infer.rs
new file mode 100644
index 0000000000000..23b76bb196470
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/downcast-infer.rs
@@ -0,0 +1,11 @@
+// compile-pass
+
+// Check that we don't try to downcast `_` when type-checking the annotation.
+fn main() {
+    let x = Some(Some(Some(1)));
+
+    match x {
+        Some::<Option<_>>(Some(Some(v))) => (),
+        _ => (),
+    }
+}
diff --git a/src/test/ui/nll/user-annotations/issue-54124.rs b/src/test/ui/nll/user-annotations/issue-54124.rs
index 042ad028575bb..e1de67aa93869 100644
--- a/src/test/ui/nll/user-annotations/issue-54124.rs
+++ b/src/test/ui/nll/user-annotations/issue-54124.rs
@@ -1,8 +1,8 @@
 #![feature(nll)]
 
 fn test<'a>() {
-    let _:fn(&()) = |_:&'a ()| {}; //~ ERROR unsatisfied lifetime constraints
-    //~^ ERROR unsatisfied lifetime constraints
+    let _:fn(&()) = |_:&'a ()| {}; //~ ERROR lifetime may not live long enough
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {
diff --git a/src/test/ui/nll/user-annotations/issue-54124.stderr b/src/test/ui/nll/user-annotations/issue-54124.stderr
index 5b5afaee8df71..b1c2411e46c01 100644
--- a/src/test/ui/nll/user-annotations/issue-54124.stderr
+++ b/src/test/ui/nll/user-annotations/issue-54124.stderr
@@ -1,19 +1,19 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-54124.rs:4:22
    |
 LL | fn test<'a>() {
    |         -- lifetime `'a` defined here
-LL |     let _:fn(&()) = |_:&'a ()| {}; //~ ERROR unsatisfied lifetime constraints
+LL |     let _:fn(&()) = |_:&'a ()| {}; //~ ERROR lifetime may not live long enough
    |                      ^ - let's call the lifetime of this reference `'1`
    |                      |
    |                      requires that `'1` must outlive `'a`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/issue-54124.rs:4:22
    |
 LL | fn test<'a>() {
    |         -- lifetime `'a` defined here
-LL |     let _:fn(&()) = |_:&'a ()| {}; //~ ERROR unsatisfied lifetime constraints
+LL |     let _:fn(&()) = |_:&'a ()| {}; //~ ERROR lifetime may not live long enough
    |                      ^ requires that `'a` must outlive `'static`
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/nll/user-annotations/issue-55241.rs b/src/test/ui/nll/user-annotations/issue-55241.rs
index e5600803df856..d7686b9dc9411 100644
--- a/src/test/ui/nll/user-annotations/issue-55241.rs
+++ b/src/test/ui/nll/user-annotations/issue-55241.rs
@@ -18,7 +18,7 @@ pub trait NodeCodec<H: Hasher> {
 }
 
 pub trait Trie<H: Hasher, C: NodeCodec<H>> {
-    /// Return the root of the trie.
+    /// Returns the root of the trie.
     fn root(&self) -> &H::Out;
 
     /// Is the trie empty?
diff --git a/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs
new file mode 100644
index 0000000000000..f4969bb4067c7
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.rs
@@ -0,0 +1,40 @@
+// Check that repeated type variables are correctly handled
+
+#![allow(unused)]
+#![feature(nll, type_ascription)]
+
+type PairUncoupled<'a, 'b, T> = (&'a T, &'b T);
+type PairCoupledTypes<T> = (T, T);
+type PairCoupledRegions<'a, T> = (&'a T, &'a T);
+
+fn uncoupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairUncoupled<_>,);
+    y // OK
+}
+
+fn coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairCoupledTypes<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),): (PairCoupledRegions<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn cast_uncoupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairUncoupled<_>,);
+    y // OK
+}
+
+fn cast_coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairCoupledTypes<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn cast_coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+    let ((y, _z),) = ((s, _x),) as (PairCoupledRegions<_>,);
+    y //~ ERROR lifetime may not live long enough
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr
new file mode 100644
index 0000000000000..76be637220a15
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/issue-57731-ascibed-coupled-types.stderr
@@ -0,0 +1,38 @@
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:17:5
+   |
+LL | fn coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                      -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),): (PairCoupledTypes<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:22:5
+   |
+LL | fn coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                        -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),): (PairCoupledRegions<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:32:5
+   |
+LL | fn cast_coupled_wilds_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                           -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),) as (PairCoupledTypes<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/issue-57731-ascibed-coupled-types.rs:37:5
+   |
+LL | fn cast_coupled_regions_rhs<'a>(_x: &'a u32, s: &'static u32) -> &'static u32 {
+   |                             -- lifetime `'a` defined here
+LL |     let ((y, _z),) = ((s, _x),) as (PairCoupledRegions<_>,);
+LL |     y //~ ERROR lifetime may not live long enough
+   |     ^ returning this value requires that `'a` must outlive `'static`
+
+error: aborting due to 4 previous errors
+
diff --git a/src/test/ui/nll/user-annotations/patterns.stderr b/src/test/ui/nll/user-annotations/patterns.stderr
index b0c554e6ca1d4..476578e074dac 100644
--- a/src/test/ui/nll/user-annotations/patterns.stderr
+++ b/src/test/ui/nll/user-annotations/patterns.stderr
@@ -148,7 +148,7 @@ LL |         value1: &x, //~ ERROR
 LL | }
    | - `x` dropped here while still borrowed
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/patterns.rs:113:5
    |
 LL | fn static_to_a_to_static_through_variable<'a>(x: &'a u32) -> &'static u32 {
@@ -157,7 +157,7 @@ LL | fn static_to_a_to_static_through_variable<'a>(x: &'a u32) -> &'static u32 {
 LL |     y //~ ERROR
    |     ^ returning this value requires that `'a` must outlive `'static`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/patterns.rs:125:5
    |
 LL | fn static_to_a_to_static_through_tuple<'a>(x: &'a u32) -> &'static u32 {
@@ -166,7 +166,7 @@ LL | fn static_to_a_to_static_through_tuple<'a>(x: &'a u32) -> &'static u32 {
 LL |     y //~ ERROR
    |     ^ returning this value requires that `'a` must outlive `'static`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/patterns.rs:130:5
    |
 LL | fn static_to_a_to_static_through_struct<'a>(_x: &'a u32) -> &'static u32 {
@@ -175,7 +175,7 @@ LL |     let Single { value: y }: Single<&'a u32> = Single { value: &22 };
 LL |     y //~ ERROR
    |     ^ returning this value requires that `'a` must outlive `'static`
 
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/patterns.rs:134:18
    |
 LL | fn a_to_static_then_static<'a>(x: &'a u32) -> &'static u32 {
diff --git a/src/test/ui/nll/user-annotations/wf-self-type.rs b/src/test/ui/nll/user-annotations/wf-self-type.rs
index da9ef8c89a169..d8caf4693b504 100644
--- a/src/test/ui/nll/user-annotations/wf-self-type.rs
+++ b/src/test/ui/nll/user-annotations/wf-self-type.rs
@@ -9,7 +9,7 @@ impl<'a, 'b> Foo<'a, 'b> {
 }
 
 pub fn foo<'a, 'b>(u: &'b ()) -> &'a () {
-    Foo::xmute(u) //~ ERROR unsatisfied lifetime constraints
+    Foo::xmute(u) //~ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/user-annotations/wf-self-type.stderr b/src/test/ui/nll/user-annotations/wf-self-type.stderr
index 401fe2a058a60..00500c8d6541f 100644
--- a/src/test/ui/nll/user-annotations/wf-self-type.stderr
+++ b/src/test/ui/nll/user-annotations/wf-self-type.stderr
@@ -1,11 +1,11 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/wf-self-type.rs:12:5
    |
 LL | pub fn foo<'a, 'b>(u: &'b ()) -> &'a () {
    |            --  -- lifetime `'b` defined here
    |            |
    |            lifetime `'a` defined here
-LL |     Foo::xmute(u) //~ ERROR unsatisfied lifetime constraints
+LL |     Foo::xmute(u) //~ ERROR lifetime may not live long enough
    |     ^^^^^^^^^^^^^ returning this value requires that `'b` must outlive `'a`
 
 error: aborting due to previous error
diff --git a/src/test/ui/nll/where_clauses_in_functions.rs b/src/test/ui/nll/where_clauses_in_functions.rs
index 256ec6000faa7..0d35c09b8ef07 100644
--- a/src/test/ui/nll/where_clauses_in_functions.rs
+++ b/src/test/ui/nll/where_clauses_in_functions.rs
@@ -11,7 +11,7 @@ where
 
 fn bar<'a, 'b>(x: &'a u32, y: &'b u32) -> (&'a u32, &'b u32) {
     foo(x, y)
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/where_clauses_in_functions.stderr b/src/test/ui/nll/where_clauses_in_functions.stderr
index 4419a19010c9e..f3b65ec31ac7d 100644
--- a/src/test/ui/nll/where_clauses_in_functions.stderr
+++ b/src/test/ui/nll/where_clauses_in_functions.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/where_clauses_in_functions.rs:13:5
    |
 LL | fn bar<'a, 'b>(x: &'a u32, y: &'b u32) -> (&'a u32, &'b u32) {
diff --git a/src/test/ui/nll/where_clauses_in_structs.rs b/src/test/ui/nll/where_clauses_in_structs.rs
index 1b02f26a67837..8bc6b2e4a4fbb 100644
--- a/src/test/ui/nll/where_clauses_in_structs.rs
+++ b/src/test/ui/nll/where_clauses_in_structs.rs
@@ -11,7 +11,7 @@ struct Foo<'a: 'b, 'b> {
 
 fn bar<'a, 'b>(x: Cell<&'a u32>, y: Cell<&'b u32>) {
     Foo { x, y };
-    //~^ ERROR unsatisfied lifetime constraints
+    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/nll/where_clauses_in_structs.stderr b/src/test/ui/nll/where_clauses_in_structs.stderr
index 8704b0dc85c21..e0feb40273f6b 100644
--- a/src/test/ui/nll/where_clauses_in_structs.stderr
+++ b/src/test/ui/nll/where_clauses_in_structs.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/where_clauses_in_structs.rs:13:11
    |
 LL | fn bar<'a, 'b>(x: Cell<&'a u32>, y: Cell<&'b u32>) {
diff --git a/src/test/ui/no-capture-arc.nll.stderr b/src/test/ui/no-capture-arc.nll.stderr
index a3bb56024c454..476b6f75abb46 100644
--- a/src/test/ui/no-capture-arc.nll.stderr
+++ b/src/test/ui/no-capture-arc.nll.stderr
@@ -1,6 +1,9 @@
 error[E0382]: borrow of moved value: `arc_v`
   --> $DIR/no-capture-arc.rs:14:18
    |
+LL |     let arc_v = Arc::new(v);
+   |         ----- move occurs because `arc_v` has type `std::sync::Arc<std::vec::Vec<i32>>`, which does not implement the `Copy` trait
+LL | 
 LL |     thread::spawn(move|| {
    |                   ------ value moved into closure here
 LL |         assert_eq!((*arc_v)[3], 4);
@@ -8,8 +11,6 @@ LL |         assert_eq!((*arc_v)[3], 4);
 ...
 LL |     assert_eq!((*arc_v)[2], 3);
    |                  ^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `arc_v` has type `std::sync::Arc<std::vec::Vec<i32>>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/no-reuse-move-arc.nll.stderr b/src/test/ui/no-reuse-move-arc.nll.stderr
index e24edc5e8e3ca..0b14f65a77073 100644
--- a/src/test/ui/no-reuse-move-arc.nll.stderr
+++ b/src/test/ui/no-reuse-move-arc.nll.stderr
@@ -1,6 +1,9 @@
 error[E0382]: borrow of moved value: `arc_v`
   --> $DIR/no-reuse-move-arc.rs:12:18
    |
+LL |     let arc_v = Arc::new(v);
+   |         ----- move occurs because `arc_v` has type `std::sync::Arc<std::vec::Vec<i32>>`, which does not implement the `Copy` trait
+LL | 
 LL |     thread::spawn(move|| {
    |                   ------ value moved into closure here
 LL |         assert_eq!((*arc_v)[3], 4);
@@ -8,8 +11,6 @@ LL |         assert_eq!((*arc_v)[3], 4);
 ...
 LL |     assert_eq!((*arc_v)[2], 3); //~ ERROR use of moved value: `arc_v`
    |                  ^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `arc_v` has type `std::sync::Arc<std::vec::Vec<i32>>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/on-unimplemented/bad-annotation.rs b/src/test/ui/on-unimplemented/bad-annotation.rs
index 6843c4bfa998a..846db63024cfb 100644
--- a/src/test/ui/on-unimplemented/bad-annotation.rs
+++ b/src/test/ui/on-unimplemented/bad-annotation.rs
@@ -10,7 +10,7 @@ trait Foo<Bar, Baz, Quux>
 
 #[rustc_on_unimplemented="a collection of type `{Self}` cannot be built from an iterator over elements of type `{A}`"]
 trait MyFromIterator<A> {
-    /// Build a container with elements from an external iterator.
+    /// Builds a container with elements from an external iterator.
     fn my_from_iter<T: Iterator<Item=A>>(iterator: T) -> Self;
 }
 
diff --git a/src/test/ui/on-unimplemented/on-trait.rs b/src/test/ui/on-unimplemented/on-trait.rs
index 22afda16f433a..109cb5ba96942 100644
--- a/src/test/ui/on-unimplemented/on-trait.rs
+++ b/src/test/ui/on-unimplemented/on-trait.rs
@@ -15,7 +15,7 @@ fn foobar<U: Clone, T: Foo<u8, U, u32>>() -> T {
 
 #[rustc_on_unimplemented="a collection of type `{Self}` cannot be built from an iterator over elements of type `{A}`"]
 trait MyFromIterator<A> {
-    /// Build a container with elements from an external iterator.
+    /// Builds a container with elements from an external iterator.
     fn my_from_iter<T: Iterator<Item=A>>(iterator: T) -> Self;
 }
 
diff --git a/src/test/ui/on-unimplemented/slice-index.stderr b/src/test/ui/on-unimplemented/slice-index.stderr
index 3a32e13e0aa6c..7b45d848c97b7 100644
--- a/src/test/ui/on-unimplemented/slice-index.stderr
+++ b/src/test/ui/on-unimplemented/slice-index.stderr
@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `i32: std::slice::SliceIndex<[i32]>` is not satisfied
+error[E0277]: the type `[i32]` cannot be indexed by `i32`
   --> $DIR/slice-index.rs:11:5
    |
 LL |     x[1i32]; //~ ERROR E0277
@@ -7,7 +7,7 @@ LL |     x[1i32]; //~ ERROR E0277
    = help: the trait `std::slice::SliceIndex<[i32]>` is not implemented for `i32`
    = note: required because of the requirements on the impl of `std::ops::Index<i32>` for `[i32]`
 
-error[E0277]: the trait bound `std::ops::RangeTo<i32>: std::slice::SliceIndex<[i32]>` is not satisfied
+error[E0277]: the type `[i32]` cannot be indexed by `std::ops::RangeTo<i32>`
   --> $DIR/slice-index.rs:12:5
    |
 LL |     x[..1i32]; //~ ERROR E0277
diff --git a/src/test/ui/once-cant-call-twice-on-heap.nll.stderr b/src/test/ui/once-cant-call-twice-on-heap.nll.stderr
new file mode 100644
index 0000000000000..ea53abc1b0f2d
--- /dev/null
+++ b/src/test/ui/once-cant-call-twice-on-heap.nll.stderr
@@ -0,0 +1,15 @@
+error[E0382]: use of moved value: `blk`
+  --> $DIR/once-cant-call-twice-on-heap.rs:9:5
+   |
+LL | fn foo<F:FnOnce()>(blk: F) {
+   |        -           --- move occurs because `blk` has type `F`, which does not implement the `Copy` trait
+   |        |
+   |        consider adding a `Copy` constraint to this type argument
+LL |     blk();
+   |     --- value moved here
+LL |     blk(); //~ ERROR use of moved value
+   |     ^^^ value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/parenthesised-deref-suggestion.rs b/src/test/ui/parenthesized-deref-suggestion.rs
similarity index 100%
rename from src/test/ui/parenthesised-deref-suggestion.rs
rename to src/test/ui/parenthesized-deref-suggestion.rs
diff --git a/src/test/ui/parenthesised-deref-suggestion.stderr b/src/test/ui/parenthesized-deref-suggestion.stderr
similarity index 88%
rename from src/test/ui/parenthesised-deref-suggestion.stderr
rename to src/test/ui/parenthesized-deref-suggestion.stderr
index 71a2bf67f06ae..fd9b0e8216b41 100644
--- a/src/test/ui/parenthesised-deref-suggestion.stderr
+++ b/src/test/ui/parenthesized-deref-suggestion.stderr
@@ -1,5 +1,5 @@
 error[E0609]: no field `opts` on type `*const Session`
-  --> $DIR/parenthesised-deref-suggestion.rs:7:30
+  --> $DIR/parenthesized-deref-suggestion.rs:7:30
    |
 LL |     (sess as *const Session).opts; //~ ERROR no field `opts` on type `*const Session`
    |                              ^^^^
@@ -9,7 +9,7 @@ LL |     (*(sess as *const Session)).opts; //~ ERROR no field `opts` on type `*c
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0609]: no field `0` on type `[u32; 1]`
-  --> $DIR/parenthesised-deref-suggestion.rs:10:21
+  --> $DIR/parenthesized-deref-suggestion.rs:10:21
    |
 LL |     (x as [u32; 1]).0; //~ ERROR no field `0` on type `[u32; 1]`
    |     ----------------^
diff --git a/src/test/ui/parser-recovery-2.stderr b/src/test/ui/parser-recovery-2.stderr
index 92d8cbc100a03..76f7af38e776d 100644
--- a/src/test/ui/parser-recovery-2.stderr
+++ b/src/test/ui/parser-recovery-2.stderr
@@ -1,3 +1,9 @@
+error: unexpected token: `;`
+  --> $DIR/parser-recovery-2.rs:12:15
+   |
+LL |     let x = y.;  //~ ERROR unexpected token
+   |               ^
+
 error: incorrect close delimiter: `)`
   --> $DIR/parser-recovery-2.rs:8:5
    |
@@ -7,12 +13,6 @@ LL |         let x = foo(); //~ ERROR cannot find function `foo` in this scope
 LL |     ) //~ ERROR incorrect close delimiter: `)`
    |     ^ incorrect close delimiter
 
-error: unexpected token: `;`
-  --> $DIR/parser-recovery-2.rs:12:15
-   |
-LL |     let x = y.;  //~ ERROR unexpected token
-   |               ^
-
 error[E0425]: cannot find function `foo` in this scope
   --> $DIR/parser-recovery-2.rs:7:17
    |
diff --git a/src/test/ui/parser/bounds-lifetime.rs b/src/test/ui/parser/bounds-lifetime.rs
index 89a969bb2e2a9..9225cfce94eb8 100644
--- a/src/test/ui/parser/bounds-lifetime.rs
+++ b/src/test/ui/parser/bounds-lifetime.rs
@@ -6,6 +6,6 @@ type A = for<'a: 'b + 'c> fn(); // OK (rejected later by ast_validation)
 type A = for<'a: 'b,> fn(); // OK(rejected later by ast_validation)
 type A = for<'a: 'b +> fn(); // OK (rejected later by ast_validation)
 type A = for<'a, T> fn(); // OK (rejected later by ast_validation)
-type A = for<,> fn(); //~ ERROR expected one of `>`, identifier, or lifetime, found `,`
+type A = for<,> fn(); //~ ERROR expected one of `>`, `const`, identifier, or lifetime, found `,`
 
 fn main() {}
diff --git a/src/test/ui/parser/bounds-lifetime.stderr b/src/test/ui/parser/bounds-lifetime.stderr
index f39e5beb6ac90..191ea3ebd070a 100644
--- a/src/test/ui/parser/bounds-lifetime.stderr
+++ b/src/test/ui/parser/bounds-lifetime.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, or lifetime, found `,`
+error: expected one of `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/bounds-lifetime.rs:9:14
    |
-LL | type A = for<,> fn(); //~ ERROR expected one of `>`, identifier, or lifetime, found `,`
-   |              ^ expected one of `>`, identifier, or lifetime here
+LL | type A = for<,> fn(); //~ ERROR expected one of `>`, `const`, identifier, or lifetime, found `,`
+   |              ^ expected one of `>`, `const`, identifier, or lifetime here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/doc-before-eof.stderr b/src/test/ui/parser/doc-before-eof.stderr
index b764e9f7ae102..5809d64e80678 100644
--- a/src/test/ui/parser/doc-before-eof.stderr
+++ b/src/test/ui/parser/doc-before-eof.stderr
@@ -2,7 +2,7 @@ error: expected item after doc comment
   --> $DIR/doc-before-eof.rs:3:1
    |
 LL | /// hi //~ERROR expected item after doc comment
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this doc comment doesn't document anything
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/doc-before-extern-rbrace.stderr b/src/test/ui/parser/doc-before-extern-rbrace.stderr
index 47fab7b40f4cd..8cc9c916a7afd 100644
--- a/src/test/ui/parser/doc-before-extern-rbrace.stderr
+++ b/src/test/ui/parser/doc-before-extern-rbrace.stderr
@@ -2,7 +2,7 @@ error: expected item after doc comment
   --> $DIR/doc-before-extern-rbrace.rs:2:5
    |
 LL |     /// hi
-   |     ^^^^^^
+   |     ^^^^^^ this doc comment doesn't document anything
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/doc-before-mod-rbrace.stderr b/src/test/ui/parser/doc-before-mod-rbrace.stderr
index 41c1d706b3a7e..4eaf351f676c8 100644
--- a/src/test/ui/parser/doc-before-mod-rbrace.stderr
+++ b/src/test/ui/parser/doc-before-mod-rbrace.stderr
@@ -2,7 +2,7 @@ error: expected item after doc comment
   --> $DIR/doc-before-mod-rbrace.rs:4:5
    |
 LL |     /// document
-   |     ^^^^^^^^^^^^
+   |     ^^^^^^^^^^^^ this doc comment doesn't document anything
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-10636-2.rs b/src/test/ui/parser/issue-10636-2.rs
index a02fd41b349c2..6fb63639d5f60 100644
--- a/src/test/ui/parser/issue-10636-2.rs
+++ b/src/test/ui/parser/issue-10636-2.rs
@@ -5,7 +5,7 @@ pub fn trace_option(option: Option<isize>) {
     option.map(|some| 42;
                           //~^ ERROR: expected one of
 
-} //~ ERROR: incorrect close delimiter
+}
 //~^ ERROR: expected expression, found `)`
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-10636-2.stderr b/src/test/ui/parser/issue-10636-2.stderr
index 9b3115cb3f4b7..38d57ce572365 100644
--- a/src/test/ui/parser/issue-10636-2.stderr
+++ b/src/test/ui/parser/issue-10636-2.stderr
@@ -1,25 +1,17 @@
-error: incorrect close delimiter: `}`
-  --> $DIR/issue-10636-2.rs:8:1
-   |
-LL | pub fn trace_option(option: Option<isize>) {
-   |                                            - close delimiter possibly meant for this
-LL |     option.map(|some| 42;
-   |               - un-closed delimiter
-...
-LL | } //~ ERROR: incorrect close delimiter
-   | ^ incorrect close delimiter
-
 error: expected one of `)`, `,`, `.`, `?`, or an operator, found `;`
   --> $DIR/issue-10636-2.rs:5:25
    |
 LL |     option.map(|some| 42;
-   |                         ^ expected one of `)`, `,`, `.`, `?`, or an operator here
+   |               -         ^
+   |               |         |
+   |               |         help: `)` may belong here
+   |               unclosed delimiter
 
 error: expected expression, found `)`
   --> $DIR/issue-10636-2.rs:8:1
    |
-LL | } //~ ERROR: incorrect close delimiter
+LL | }
    | ^ expected expression
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/issue-14303-enum.stderr b/src/test/ui/parser/issue-14303-enum.stderr
index a31429e7228c5..bcecd75b1abba 100644
--- a/src/test/ui/parser/issue-14303-enum.stderr
+++ b/src/test/ui/parser/issue-14303-enum.stderr
@@ -2,11 +2,7 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/issue-14303-enum.rs:1:15
    |
 LL | enum X<'a, T, 'b> {
-   |               ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | enum X<'a, 'b, T> {
-   |            ^^^ --
+   |       --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-fn-def.stderr b/src/test/ui/parser/issue-14303-fn-def.stderr
index 4582aeef428d3..082c37e0be795 100644
--- a/src/test/ui/parser/issue-14303-fn-def.stderr
+++ b/src/test/ui/parser/issue-14303-fn-def.stderr
@@ -2,11 +2,7 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/issue-14303-fn-def.rs:1:15
    |
 LL | fn foo<'a, T, 'b>(x: &'a T) {}
-   |               ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | fn foo<'a, 'b, T>(x: &'a T) {}
-   |            ^^^ --
+   |       --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-fncall.rs b/src/test/ui/parser/issue-14303-fncall.rs
index 17b9b766b2181..39694198cdb4d 100644
--- a/src/test/ui/parser/issue-14303-fncall.rs
+++ b/src/test/ui/parser/issue-14303-fncall.rs
@@ -11,7 +11,7 @@ fn foo<'a, 'b>(start: &'a usize, end: &'a usize) {
     let _x = (*start..*end)
         .map(|x| S { a: start, b: end })
         .collect::<Vec<S<_, 'a>>>();
-        //~^ ERROR lifetime parameters must be declared prior to type parameters
+        //~^ ERROR lifetime arguments must be declared prior to type arguments
 }
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-14303-fncall.stderr b/src/test/ui/parser/issue-14303-fncall.stderr
index 2a7364915949e..8ef9f1a1a6c79 100644
--- a/src/test/ui/parser/issue-14303-fncall.stderr
+++ b/src/test/ui/parser/issue-14303-fncall.stderr
@@ -1,12 +1,8 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime arguments must be declared prior to type arguments
   --> $DIR/issue-14303-fncall.rs:13:29
    |
 LL |         .collect::<Vec<S<_, 'a>>>();
-   |                             ^^ must be declared prior to type parameters
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL |         .collect::<Vec<S<'a, _>>>();
-   |                          ^^^ --
+   |                             ^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-impl.stderr b/src/test/ui/parser/issue-14303-impl.stderr
index a1953396153e0..3b5615d2a9eca 100644
--- a/src/test/ui/parser/issue-14303-impl.stderr
+++ b/src/test/ui/parser/issue-14303-impl.stderr
@@ -2,11 +2,7 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/issue-14303-impl.rs:3:13
    |
 LL | impl<'a, T, 'b> X<T> {}
-   |             ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | impl<'a, 'b, T> X<T> {}
-   |          ^^^ --
+   |     --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-path.rs b/src/test/ui/parser/issue-14303-path.rs
index a08c89f3437b4..386d19859e4a8 100644
--- a/src/test/ui/parser/issue-14303-path.rs
+++ b/src/test/ui/parser/issue-14303-path.rs
@@ -8,6 +8,6 @@ mod foo {
 }
 
 fn bar<'a, 'b, 'c, T>(x: foo::X<'a, T, 'b, 'c>) {}
-//~^ ERROR lifetime parameters must be declared prior to type parameters
+//~^ ERROR lifetime arguments must be declared prior to type arguments
 
 fn main() {}
diff --git a/src/test/ui/parser/issue-14303-path.stderr b/src/test/ui/parser/issue-14303-path.stderr
index fb4fb32e11e50..19f2995ebee53 100644
--- a/src/test/ui/parser/issue-14303-path.stderr
+++ b/src/test/ui/parser/issue-14303-path.stderr
@@ -1,14 +1,8 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime arguments must be declared prior to type arguments
   --> $DIR/issue-14303-path.rs:10:40
    |
 LL | fn bar<'a, 'b, 'c, T>(x: foo::X<'a, T, 'b, 'c>) {}
-   |                                        ^^  ^^ must be declared prior to type parameters
-   |                                        |
-   |                                        must be declared prior to type parameters
-help: move the lifetime parameters prior to the first type parameter
-   |
-LL | fn bar<'a, 'b, 'c, T>(x: foo::X<'a, 'b, 'c, T>) {}
-   |                                     ^^^ ^^^ --
+   |                                        ^^  ^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-struct.stderr b/src/test/ui/parser/issue-14303-struct.stderr
index 668b8d1de6899..dbd0b987dd190 100644
--- a/src/test/ui/parser/issue-14303-struct.stderr
+++ b/src/test/ui/parser/issue-14303-struct.stderr
@@ -2,11 +2,7 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/issue-14303-struct.rs:1:17
    |
 LL | struct X<'a, T, 'b> {
-   |                 ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | struct X<'a, 'b, T> {
-   |              ^^^ --
+   |         --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-14303-trait.stderr b/src/test/ui/parser/issue-14303-trait.stderr
index 11ce0c44351ad..7dfa62d823fd8 100644
--- a/src/test/ui/parser/issue-14303-trait.stderr
+++ b/src/test/ui/parser/issue-14303-trait.stderr
@@ -2,11 +2,7 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/issue-14303-trait.rs:1:18
    |
 LL | trait Foo<'a, T, 'b> {}
-   |                  ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | trait Foo<'a, 'b, T> {}
-   |               ^^^ --
+   |          --------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, T>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-17718-const-mut.rs b/src/test/ui/parser/issue-17718-const-mut.rs
index 4e74516d6b6fb..795a8c7631d9a 100644
--- a/src/test/ui/parser/issue-17718-const-mut.rs
+++ b/src/test/ui/parser/issue-17718-const-mut.rs
@@ -1,6 +1,6 @@
 const
 mut //~ ERROR: const globals cannot be mutable
-//~^ HELP did you mean to declare a static?
+//~^^ HELP you might want to declare a static instead
 FOO: usize = 3;
 
 fn main() {
diff --git a/src/test/ui/parser/issue-17718-const-mut.stderr b/src/test/ui/parser/issue-17718-const-mut.stderr
index 29a65ebe41889..19f9fe19ef5ab 100644
--- a/src/test/ui/parser/issue-17718-const-mut.stderr
+++ b/src/test/ui/parser/issue-17718-const-mut.stderr
@@ -1,10 +1,10 @@
 error: const globals cannot be mutable
   --> $DIR/issue-17718-const-mut.rs:2:1
    |
+LL | const
+   | ----- help: you might want to declare a static instead: `static`
 LL | mut //~ ERROR: const globals cannot be mutable
-   | ^^^
-   |
-   = help: did you mean to declare a static?
+   | ^^^ cannot be mutable
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/issue-32214.rs b/src/test/ui/parser/issue-32214.rs
index 7e55bc038e766..7191a3234c083 100644
--- a/src/test/ui/parser/issue-32214.rs
+++ b/src/test/ui/parser/issue-32214.rs
@@ -3,6 +3,6 @@
 trait Trait<T> { type Item; }
 
 pub fn test<W, I: Trait<Item=(), W> >() {}
-//~^ ERROR type parameters must be declared prior to associated type bindings
+//~^ ERROR associated type bindings must be declared after generic parameters
 
 fn main() { }
diff --git a/src/test/ui/parser/issue-32214.stderr b/src/test/ui/parser/issue-32214.stderr
index a889513eaee52..7022019a22f26 100644
--- a/src/test/ui/parser/issue-32214.stderr
+++ b/src/test/ui/parser/issue-32214.stderr
@@ -1,8 +1,10 @@
-error: type parameters must be declared prior to associated type bindings
-  --> $DIR/issue-32214.rs:5:34
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/issue-32214.rs:5:25
    |
 LL | pub fn test<W, I: Trait<Item=(), W> >() {}
-   |                                  ^ must be declared prior to associated type bindings
+   |                         -------^^^
+   |                         |
+   |                         this associated type binding should be moved after the generic parameters
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/lex-bad-char-literals-2.rs b/src/test/ui/parser/lex-bad-char-literals-2.rs
index 7f859995218d9..1e180f87fc186 100644
--- a/src/test/ui/parser/lex-bad-char-literals-2.rs
+++ b/src/test/ui/parser/lex-bad-char-literals-2.rs
@@ -1,4 +1,4 @@
 // This test needs to the last one appearing in this file as it kills the parser
 static c: char =
-    'nope' //~ ERROR: character literal may only contain one codepoint: 'nope'
+    'nope' //~ ERROR: character literal may only contain one codepoint
 ;
diff --git a/src/test/ui/parser/lex-bad-char-literals-2.stderr b/src/test/ui/parser/lex-bad-char-literals-2.stderr
index a7075b7187812..7eadb8ebfe06d 100644
--- a/src/test/ui/parser/lex-bad-char-literals-2.stderr
+++ b/src/test/ui/parser/lex-bad-char-literals-2.stderr
@@ -1,8 +1,13 @@
-error: character literal may only contain one codepoint: 'nope'
+error: character literal may only contain one codepoint
   --> $DIR/lex-bad-char-literals-2.rs:3:5
    |
-LL |     'nope' //~ ERROR: character literal may only contain one codepoint: 'nope'
+LL |     'nope' //~ ERROR: character literal may only contain one codepoint
    |     ^^^^^^
 
-error: aborting due to previous error
+error[E0601]: `main` function not found in crate `lex_bad_char_literals_2`
+   |
+   = note: consider adding a `main` function to `$DIR/lex-bad-char-literals-2.rs`
+
+error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0601`.
diff --git a/src/test/ui/parser/lex-bad-char-literals-3.rs b/src/test/ui/parser/lex-bad-char-literals-3.rs
index f8749708f7721..5194ff4d9354f 100644
--- a/src/test/ui/parser/lex-bad-char-literals-3.rs
+++ b/src/test/ui/parser/lex-bad-char-literals-3.rs
@@ -1,7 +1,7 @@
-// This test needs to the last one appearing in this file as it kills the parser
-static c: char =
-    '●●' //~ ERROR: character literal may only contain one codepoint
-         //~| ERROR: mismatched types
-;
+static c: char = '●●';
+//~^ ERROR: character literal may only contain one codepoint
 
-fn main() {}
+fn main() {
+    let ch: &str = '●●';
+    //~^ ERROR: character literal may only contain one codepoint
+}
diff --git a/src/test/ui/parser/lex-bad-char-literals-3.stderr b/src/test/ui/parser/lex-bad-char-literals-3.stderr
index 89f18e3e2aa4d..6462a3c0e57ba 100644
--- a/src/test/ui/parser/lex-bad-char-literals-3.stderr
+++ b/src/test/ui/parser/lex-bad-char-literals-3.stderr
@@ -1,22 +1,22 @@
 error: character literal may only contain one codepoint
-  --> $DIR/lex-bad-char-literals-3.rs:3:5
+  --> $DIR/lex-bad-char-literals-3.rs:1:18
    |
-LL |     '●●' //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^
+LL | static c: char = '●●';
+   |                  ^^^^
 help: if you meant to write a `str` literal, use double quotes
    |
-LL |     "●●" //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^
+LL | static c: char = "●●";
+   |                  ^^^^
 
-error[E0308]: mismatched types
-  --> $DIR/lex-bad-char-literals-3.rs:3:5
+error: character literal may only contain one codepoint
+  --> $DIR/lex-bad-char-literals-3.rs:5:20
    |
-LL |     '●●' //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^ expected char, found reference
+LL |     let ch: &str = '●●';
+   |                    ^^^^
+help: if you meant to write a `str` literal, use double quotes
    |
-   = note: expected type `char`
-              found type `&'static str`
+LL |     let ch: &str = "●●";
+   |                    ^^^^
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/parser/lex-bad-char-literals-4.rs b/src/test/ui/parser/lex-bad-char-literals-4.rs
index 966e2bb949688..e13f11f36df48 100644
--- a/src/test/ui/parser/lex-bad-char-literals-4.rs
+++ b/src/test/ui/parser/lex-bad-char-literals-4.rs
@@ -1,5 +1,5 @@
 //
 // This test needs to the last one appearing in this file as it kills the parser
 static c: char =
-    '●  //~ ERROR: character literal may only contain one codepoint: '●
+    '●  //~ ERROR: character literal may only contain one codepoint
 ;
diff --git a/src/test/ui/parser/lex-bad-char-literals-4.stderr b/src/test/ui/parser/lex-bad-char-literals-4.stderr
index 550cb5449df19..881e3d5276bb1 100644
--- a/src/test/ui/parser/lex-bad-char-literals-4.stderr
+++ b/src/test/ui/parser/lex-bad-char-literals-4.stderr
@@ -1,7 +1,7 @@
 error: character literal may only contain one codepoint: '●
   --> $DIR/lex-bad-char-literals-4.rs:4:5
    |
-LL |     '●  //~ ERROR: character literal may only contain one codepoint: '●
+LL |     '●  //~ ERROR: character literal may only contain one codepoint
    |     ^^
 
 error: aborting due to previous error
diff --git a/src/test/ui/parser/lex-bad-char-literals-5.rs b/src/test/ui/parser/lex-bad-char-literals-5.rs
index 247289ea4d54b..0c4339edc4fa7 100644
--- a/src/test/ui/parser/lex-bad-char-literals-5.rs
+++ b/src/test/ui/parser/lex-bad-char-literals-5.rs
@@ -1,8 +1,7 @@
-//
-// This test needs to the last one appearing in this file as it kills the parser
-static c: char =
-    '\x10\x10'  //~ ERROR: character literal may only contain one codepoint
-                //~| ERROR: mismatched types
-;
+static c: char = '\x10\x10';
+//~^ ERROR: character literal may only contain one codepoint
 
-fn main() {}
+fn main() {
+    let ch: &str = '\x10\x10';
+    //~^ ERROR: character literal may only contain one codepoint
+}
diff --git a/src/test/ui/parser/lex-bad-char-literals-5.stderr b/src/test/ui/parser/lex-bad-char-literals-5.stderr
index 523d71ff49d2b..ef02973310153 100644
--- a/src/test/ui/parser/lex-bad-char-literals-5.stderr
+++ b/src/test/ui/parser/lex-bad-char-literals-5.stderr
@@ -1,22 +1,22 @@
 error: character literal may only contain one codepoint
-  --> $DIR/lex-bad-char-literals-5.rs:4:5
+  --> $DIR/lex-bad-char-literals-5.rs:1:18
    |
-LL |     '/x10/x10'  //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^^^^^^^
+LL | static c: char = '/x10/x10';
+   |                  ^^^^^^^^^^
 help: if you meant to write a `str` literal, use double quotes
    |
-LL |     "/x10/x10"  //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^^^^^^^
+LL | static c: char = "/x10/x10";
+   |                  ^^^^^^^^^^
 
-error[E0308]: mismatched types
-  --> $DIR/lex-bad-char-literals-5.rs:4:5
+error: character literal may only contain one codepoint
+  --> $DIR/lex-bad-char-literals-5.rs:5:20
    |
-LL |     '/x10/x10'  //~ ERROR: character literal may only contain one codepoint
-   |     ^^^^^^^^^^ expected char, found reference
+LL |     let ch: &str = '/x10/x10';
+   |                    ^^^^^^^^^^
+help: if you meant to write a `str` literal, use double quotes
    |
-   = note: expected type `char`
-              found type `&'static str`
+LL |     let ch: &str = "/x10/x10";
+   |                    ^^^^^^^^^^
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/parser/lex-bad-char-literals-6.rs b/src/test/ui/parser/lex-bad-char-literals-6.rs
new file mode 100644
index 0000000000000..4379b4fa6d777
--- /dev/null
+++ b/src/test/ui/parser/lex-bad-char-literals-6.rs
@@ -0,0 +1,17 @@
+fn main() {
+    let x: &str = 'ab';
+    //~^ ERROR: character literal may only contain one codepoint
+    let y: char = 'cd';
+    //~^ ERROR: character literal may only contain one codepoint
+    let z = 'ef';
+    //~^ ERROR: character literal may only contain one codepoint
+
+    if x == y {}
+    //~^ ERROR: can't compare `&str` with `char`
+    if y == z {}  // no error here
+    if x == z {}
+    //~^ ERROR: can't compare `&str` with `char`
+
+    let a: usize = "";
+    //~^ ERROR: mismatched types
+}
diff --git a/src/test/ui/parser/lex-bad-char-literals-6.stderr b/src/test/ui/parser/lex-bad-char-literals-6.stderr
new file mode 100644
index 0000000000000..df99726034878
--- /dev/null
+++ b/src/test/ui/parser/lex-bad-char-literals-6.stderr
@@ -0,0 +1,47 @@
+error: character literal may only contain one codepoint
+  --> $DIR/lex-bad-char-literals-6.rs:2:19
+   |
+LL |     let x: &str = 'ab';
+   |                   ^^^^
+
+error: character literal may only contain one codepoint
+  --> $DIR/lex-bad-char-literals-6.rs:4:19
+   |
+LL |     let y: char = 'cd';
+   |                   ^^^^
+
+error: character literal may only contain one codepoint
+  --> $DIR/lex-bad-char-literals-6.rs:6:13
+   |
+LL |     let z = 'ef';
+   |             ^^^^
+
+error[E0277]: can't compare `&str` with `char`
+  --> $DIR/lex-bad-char-literals-6.rs:9:10
+   |
+LL |     if x == y {}
+   |          ^^ no implementation for `&str == char`
+   |
+   = help: the trait `std::cmp::PartialEq<char>` is not implemented for `&str`
+
+error[E0308]: mismatched types
+  --> $DIR/lex-bad-char-literals-6.rs:15:20
+   |
+LL |     let a: usize = "";
+   |                    ^^ expected usize, found reference
+   |
+   = note: expected type `usize`
+              found type `&'static str`
+
+error[E0277]: can't compare `&str` with `char`
+  --> $DIR/lex-bad-char-literals-6.rs:12:10
+   |
+LL |     if x == z {}
+   |          ^^ no implementation for `&str == char`
+   |
+   = help: the trait `std::cmp::PartialEq<char>` is not implemented for `&str`
+
+error: aborting due to 6 previous errors
+
+Some errors occurred: E0277, E0308.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/parser/macro-mismatched-delim-paren-brace.stderr b/src/test/ui/parser/macro-mismatched-delim-paren-brace.stderr
index 805ba8b6baa60..abb0820979532 100644
--- a/src/test/ui/parser/macro-mismatched-delim-paren-brace.stderr
+++ b/src/test/ui/parser/macro-mismatched-delim-paren-brace.stderr
@@ -1,3 +1,9 @@
+error: unexpected close delimiter: `}`
+  --> $DIR/macro-mismatched-delim-paren-brace.rs:5:1
+   |
+LL | } //~ ERROR unexpected close delimiter: `}`
+   | ^ unexpected close delimiter
+
 error: incorrect close delimiter: `}`
   --> $DIR/macro-mismatched-delim-paren-brace.rs:4:5
    |
@@ -7,11 +13,5 @@ LL |         bar, "baz", 1, 2.0
 LL |     } //~ ERROR incorrect close delimiter
    |     ^ incorrect close delimiter
 
-error: unexpected close delimiter: `}`
-  --> $DIR/macro-mismatched-delim-paren-brace.rs:5:1
-   |
-LL | } //~ ERROR unexpected close delimiter: `}`
-   | ^ unexpected close delimiter
-
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/parser/regions-out-of-scope-slice.rs b/src/test/ui/parser/regions-out-of-scope-slice.rs
index 2cc9b1ac45c7d..21369d0be61b1 100644
--- a/src/test/ui/parser/regions-out-of-scope-slice.rs
+++ b/src/test/ui/parser/regions-out-of-scope-slice.rs
@@ -1,8 +1,6 @@
-// blk region isn't supported in the front-end
+// This basically tests the parser's recovery on `'blk` in the wrong place.
 
 fn foo(cond: bool) {
-    // Here we will infer a type that uses the
-    // region of the if stmt then block, but in the scope:
     let mut x;
 
     if cond {
diff --git a/src/test/ui/parser/regions-out-of-scope-slice.stderr b/src/test/ui/parser/regions-out-of-scope-slice.stderr
index 026d14ca41392..cd56dfa6aeb7b 100644
--- a/src/test/ui/parser/regions-out-of-scope-slice.stderr
+++ b/src/test/ui/parser/regions-out-of-scope-slice.stderr
@@ -1,5 +1,5 @@
 error: expected `:`, found `[`
-  --> $DIR/regions-out-of-scope-slice.rs:9:19
+  --> $DIR/regions-out-of-scope-slice.rs:7:19
    |
 LL |         x = &'blk [1,2,3]; //~ ERROR expected `:`, found `[`
    |                   ^ expected `:`
diff --git a/src/test/ui/parser/removed-syntax-uniq-mut-ty.rs b/src/test/ui/parser/removed-syntax-uniq-mut-ty.rs
index 12de76d9d6d9f..79d51f5595d26 100644
--- a/src/test/ui/parser/removed-syntax-uniq-mut-ty.rs
+++ b/src/test/ui/parser/removed-syntax-uniq-mut-ty.rs
@@ -1 +1 @@
-type mut_box = Box<mut isize>; //~ ERROR expected one of `>`, lifetime, or type, found `mut`
+type mut_box = Box<mut isize>; //~ ERROR expected one of `>`, const, lifetime, or type, found `mut`
diff --git a/src/test/ui/parser/removed-syntax-uniq-mut-ty.stderr b/src/test/ui/parser/removed-syntax-uniq-mut-ty.stderr
index 0177b19d74e7e..b2759778d0313 100644
--- a/src/test/ui/parser/removed-syntax-uniq-mut-ty.stderr
+++ b/src/test/ui/parser/removed-syntax-uniq-mut-ty.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, lifetime, or type, found `mut`
+error: expected one of `>`, const, lifetime, or type, found `mut`
   --> $DIR/removed-syntax-uniq-mut-ty.rs:1:20
    |
-LL | type mut_box = Box<mut isize>; //~ ERROR expected one of `>`, lifetime, or type, found `mut`
-   |                    ^^^ expected one of `>`, lifetime, or type here
+LL | type mut_box = Box<mut isize>; //~ ERROR expected one of `>`, const, lifetime, or type, found `mut`
+   |                    ^^^ expected one of `>`, const, lifetime, or type here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/removed-syntax-with-1.rs b/src/test/ui/parser/removed-syntax-with-1.rs
index 57cbe8d5be655..2c1e152dcee75 100644
--- a/src/test/ui/parser/removed-syntax-with-1.rs
+++ b/src/test/ui/parser/removed-syntax-with-1.rs
@@ -5,7 +5,6 @@ fn main() {
     }
 
     let a = S { foo: (), bar: () };
-    let b = S { foo: () with a };
+    let b = S { foo: () with a, bar: () };
     //~^ ERROR expected one of `,`, `.`, `?`, `}`, or an operator, found `with`
-    //~| ERROR missing field `bar` in initializer of `main::S`
 }
diff --git a/src/test/ui/parser/removed-syntax-with-1.stderr b/src/test/ui/parser/removed-syntax-with-1.stderr
index 77ed4fcea517c..a157873916a64 100644
--- a/src/test/ui/parser/removed-syntax-with-1.stderr
+++ b/src/test/ui/parser/removed-syntax-with-1.stderr
@@ -1,15 +1,10 @@
 error: expected one of `,`, `.`, `?`, `}`, or an operator, found `with`
   --> $DIR/removed-syntax-with-1.rs:8:25
    |
-LL |     let b = S { foo: () with a };
-   |                         ^^^^ expected one of `,`, `.`, `?`, `}`, or an operator here
+LL |     let b = S { foo: () with a, bar: () };
+   |             -           ^^^^ expected one of `,`, `.`, `?`, `}`, or an operator here
+   |             |
+   |             while parsing this struct
 
-error[E0063]: missing field `bar` in initializer of `main::S`
-  --> $DIR/removed-syntax-with-1.rs:8:13
-   |
-LL |     let b = S { foo: () with a };
-   |             ^ missing `bar`
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0063`.
diff --git a/src/test/ui/parser/removed-syntax-with-2.rs b/src/test/ui/parser/removed-syntax-with-2.rs
index 11db391c5489a..f666da49696ba 100644
--- a/src/test/ui/parser/removed-syntax-with-2.rs
+++ b/src/test/ui/parser/removed-syntax-with-2.rs
@@ -7,6 +7,5 @@ fn main() {
     let a = S { foo: (), bar: () };
     let b = S { foo: (), with a };
     //~^ ERROR expected one of `,` or `}`, found `a`
-    //~| ERROR cannot find value `with` in this scope
-    //~| ERROR struct `main::S` has no field named `with`
+    //~| ERROR missing field `bar` in initializer of `main::S`
 }
diff --git a/src/test/ui/parser/removed-syntax-with-2.stderr b/src/test/ui/parser/removed-syntax-with-2.stderr
index 5642d2f45ffce..7717b49d3a2c7 100644
--- a/src/test/ui/parser/removed-syntax-with-2.stderr
+++ b/src/test/ui/parser/removed-syntax-with-2.stderr
@@ -2,23 +2,16 @@ error: expected one of `,` or `}`, found `a`
   --> $DIR/removed-syntax-with-2.rs:8:31
    |
 LL |     let b = S { foo: (), with a };
-   |                               ^ expected one of `,` or `}` here
+   |             -                 ^ expected one of `,` or `}` here
+   |             |
+   |             while parsing this struct
 
-error[E0425]: cannot find value `with` in this scope
-  --> $DIR/removed-syntax-with-2.rs:8:26
+error[E0063]: missing field `bar` in initializer of `main::S`
+  --> $DIR/removed-syntax-with-2.rs:8:13
    |
 LL |     let b = S { foo: (), with a };
-   |                          ^^^^ not found in this scope
+   |             ^ missing `bar`
 
-error[E0560]: struct `main::S` has no field named `with`
-  --> $DIR/removed-syntax-with-2.rs:8:26
-   |
-LL |     let b = S { foo: (), with a };
-   |                          ^^^^ `main::S` does not have this field
-   |
-   = note: available fields are: `foo`, `bar`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors occurred: E0425, E0560.
-For more information about an error, try `rustc --explain E0425`.
+For more information about this error, try `rustc --explain E0063`.
diff --git a/src/test/ui/parser/struct-field-numeric-shorthand.rs b/src/test/ui/parser/struct-field-numeric-shorthand.rs
index 914588f51e1e3..58c40b3d96a49 100644
--- a/src/test/ui/parser/struct-field-numeric-shorthand.rs
+++ b/src/test/ui/parser/struct-field-numeric-shorthand.rs
@@ -1,6 +1,9 @@
 struct Rgb(u8, u8, u8);
 
 fn main() {
-    let _ = Rgb { 0, 1, 2 }; //~ ERROR expected identifier, found `0`
-                             //~| ERROR missing fields `0`, `1`, `2` in initializer of `Rgb`
+    let _ = Rgb { 0, 1, 2 };
+    //~^ ERROR expected identifier, found `0`
+    //~| ERROR expected identifier, found `1`
+    //~| ERROR expected identifier, found `2`
+    //~| ERROR missing fields `0`, `1`, `2` in initializer of `Rgb`
 }
diff --git a/src/test/ui/parser/struct-field-numeric-shorthand.stderr b/src/test/ui/parser/struct-field-numeric-shorthand.stderr
index f5dc226934ec6..cfb1f82014754 100644
--- a/src/test/ui/parser/struct-field-numeric-shorthand.stderr
+++ b/src/test/ui/parser/struct-field-numeric-shorthand.stderr
@@ -1,17 +1,33 @@
 error: expected identifier, found `0`
   --> $DIR/struct-field-numeric-shorthand.rs:4:19
    |
-LL |     let _ = Rgb { 0, 1, 2 }; //~ ERROR expected identifier, found `0`
+LL |     let _ = Rgb { 0, 1, 2 };
    |             ---   ^ expected identifier
    |             |
    |             while parsing this struct
 
+error: expected identifier, found `1`
+  --> $DIR/struct-field-numeric-shorthand.rs:4:22
+   |
+LL |     let _ = Rgb { 0, 1, 2 };
+   |             ---      ^ expected identifier
+   |             |
+   |             while parsing this struct
+
+error: expected identifier, found `2`
+  --> $DIR/struct-field-numeric-shorthand.rs:4:25
+   |
+LL |     let _ = Rgb { 0, 1, 2 };
+   |             ---         ^ expected identifier
+   |             |
+   |             while parsing this struct
+
 error[E0063]: missing fields `0`, `1`, `2` in initializer of `Rgb`
   --> $DIR/struct-field-numeric-shorthand.rs:4:13
    |
-LL |     let _ = Rgb { 0, 1, 2 }; //~ ERROR expected identifier, found `0`
+LL |     let _ = Rgb { 0, 1, 2 };
    |             ^^^ missing `0`, `1`, `2`
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0063`.
diff --git a/src/test/ui/parser/trait-object-lifetime-parens.stderr b/src/test/ui/parser/trait-object-lifetime-parens.stderr
index a9b542ddcc4d3..94ca66aef729b 100644
--- a/src/test/ui/parser/trait-object-lifetime-parens.stderr
+++ b/src/test/ui/parser/trait-object-lifetime-parens.stderr
@@ -1,14 +1,14 @@
 error: parenthesized lifetime bounds are not supported
-  --> $DIR/trait-object-lifetime-parens.rs:5:24
+  --> $DIR/trait-object-lifetime-parens.rs:5:21
    |
 LL | fn f<'a, T: Trait + ('a)>() {} //~ ERROR parenthesized lifetime bounds are not supported
-   |                        ^
+   |                     ^^^^ help: remove the parentheses
 
 error: parenthesized lifetime bounds are not supported
-  --> $DIR/trait-object-lifetime-parens.rs:8:27
+  --> $DIR/trait-object-lifetime-parens.rs:8:24
    |
 LL |     let _: Box<Trait + ('a)>; //~ ERROR parenthesized lifetime bounds are not supported
-   |                           ^
+   |                        ^^^^ help: remove the parentheses
 
 error: expected type, found `'a`
   --> $DIR/trait-object-lifetime-parens.rs:9:17
diff --git a/src/test/ui/parser/type-parameters-in-field-exprs.stderr b/src/test/ui/parser/type-parameters-in-field-exprs.stderr
index e68e1f3204ade..2183c74da0acb 100644
--- a/src/test/ui/parser/type-parameters-in-field-exprs.stderr
+++ b/src/test/ui/parser/type-parameters-in-field-exprs.stderr
@@ -1,20 +1,20 @@
 error: field expressions may not have generic arguments
-  --> $DIR/type-parameters-in-field-exprs.rs:13:8
+  --> $DIR/type-parameters-in-field-exprs.rs:13:10
    |
 LL |     f.x::<isize>;
-   |        ^^^^^^^^^
+   |          ^^^^^^^
 
 error: field expressions may not have generic arguments
-  --> $DIR/type-parameters-in-field-exprs.rs:15:8
+  --> $DIR/type-parameters-in-field-exprs.rs:15:10
    |
 LL |     f.x::<>;
-   |        ^^^^
+   |          ^^
 
 error: field expressions may not have generic arguments
-  --> $DIR/type-parameters-in-field-exprs.rs:17:8
+  --> $DIR/type-parameters-in-field-exprs.rs:17:10
    |
 LL |     f.x::();
-   |        ^^^^
+   |          ^^
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.rs b/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.rs
new file mode 100644
index 0000000000000..50f1fe873cb5f
--- /dev/null
+++ b/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.rs
@@ -0,0 +1,17 @@
+fn unrelated() -> Result<(), std::string::ParseError> {  // #57664
+    let x = 0;
+
+    match x {
+        1 => {
+            let property_value_as_string = "a".parse()?;
+        }
+        2 => {
+            let value: &bool = unsafe { &42 };
+            //~^ ERROR mismatched types
+        }
+    };
+
+    Ok(())
+}
+
+fn main() {}
diff --git a/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.stderr b/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.stderr
new file mode 100644
index 0000000000000..edaa60e5b8d8b
--- /dev/null
+++ b/src/test/ui/point-to-type-err-cause-on-impl-trait-return-2.stderr
@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/point-to-type-err-cause-on-impl-trait-return-2.rs:9:41
+   |
+LL |             let value: &bool = unsafe { &42 };
+   |                                         ^^^ expected bool, found integer
+   |
+   = note: expected type `&bool`
+              found type `&{integer}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/point-to-type-err-cause-on-impl-trait-return.rs b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.rs
new file mode 100644
index 0000000000000..95b40368143ef
--- /dev/null
+++ b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.rs
@@ -0,0 +1,36 @@
+fn foo() -> impl std::fmt::Display {
+    if false {
+        return 0i32;
+    }
+    1u32
+    //~^ ERROR mismatched types
+}
+
+fn bar() -> impl std::fmt::Display {
+    if false {
+        return 0i32;
+    } else {
+        return 1u32;
+        //~^ ERROR mismatched types
+    }
+}
+
+fn baz() -> impl std::fmt::Display {
+    if false {
+    //~^ ERROR mismatched types
+        return 0i32;
+    } else {
+        1u32
+    }
+}
+
+fn qux() -> impl std::fmt::Display {
+    if false {
+        0i32
+    } else {
+        1u32
+        //~^ ERROR if and else have incompatible types
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr
new file mode 100644
index 0000000000000..5ebe00e624fc1
--- /dev/null
+++ b/src/test/ui/point-to-type-err-cause-on-impl-trait-return.stderr
@@ -0,0 +1,66 @@
+error[E0308]: mismatched types
+  --> $DIR/point-to-type-err-cause-on-impl-trait-return.rs:5:5
+   |
+LL | fn foo() -> impl std::fmt::Display {
+   |             ---------------------- expected because this return type...
+LL |     if false {
+LL |         return 0i32;
+   |                ---- ...is found to be `i32` here
+LL |     }
+LL |     1u32
+   |     ^^^^ expected i32, found u32
+   |
+   = note: expected type `i32`
+              found type `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/point-to-type-err-cause-on-impl-trait-return.rs:13:16
+   |
+LL | fn bar() -> impl std::fmt::Display {
+   |             ---------------------- expected because this return type...
+LL |     if false {
+LL |         return 0i32;
+   |                ---- ...is found to be `i32` here
+LL |     } else {
+LL |         return 1u32;
+   |                ^^^^ expected i32, found u32
+   |
+   = note: expected type `i32`
+              found type `u32`
+
+error[E0308]: mismatched types
+  --> $DIR/point-to-type-err-cause-on-impl-trait-return.rs:19:5
+   |
+LL |   fn baz() -> impl std::fmt::Display {
+   |               ---------------------- expected because this return type...
+LL | /     if false {
+LL | |     //~^ ERROR mismatched types
+LL | |         return 0i32;
+   | |                ---- ...is found to be `i32` here
+LL | |     } else {
+LL | |         1u32
+LL | |     }
+   | |_____^ expected i32, found u32
+   |
+   = note: expected type `i32`
+              found type `u32`
+
+error[E0308]: if and else have incompatible types
+  --> $DIR/point-to-type-err-cause-on-impl-trait-return.rs:31:9
+   |
+LL | /     if false {
+LL | |         0i32
+   | |         ---- expected because of this
+LL | |     } else {
+LL | |         1u32
+   | |         ^^^^ expected i32, found u32
+LL | |         //~^ ERROR if and else have incompatible types
+LL | |     }
+   | |_____- if and else have incompatible types
+   |
+   = note: expected type `i32`
+              found type `u32`
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/privacy/private-in-public-assoc-ty.rs b/src/test/ui/privacy/private-in-public-assoc-ty.rs
index c6e86ed64ae73..81d23959fd4ad 100644
--- a/src/test/ui/privacy/private-in-public-assoc-ty.rs
+++ b/src/test/ui/privacy/private-in-public-assoc-ty.rs
@@ -1,7 +1,7 @@
 // Private types and traits are not allowed in interfaces of associated types.
 // This test also ensures that the checks are performed even inside private modules.
 
-#![feature(associated_type_defaults)]
+#![feature(associated_type_defaults, existential_type)]
 
 mod m {
     struct Priv;
@@ -23,10 +23,17 @@ mod m {
 
         type Alias4 = Priv;
         //~^ ERROR private type `m::Priv` in public interface
+
+        type Exist;
+        fn infer_exist() -> Self::Exist;
     }
     impl PubTr for u8 {
         type Alias1 = Priv;
         //~^ ERROR private type `m::Priv` in public interface
+
+        existential type Exist: PrivTr;
+        //~^ ERROR private trait `m::PrivTr` in public interface
+        fn infer_exist() -> Self::Exist { Priv }
     }
 }
 
diff --git a/src/test/ui/privacy/private-in-public-assoc-ty.stderr b/src/test/ui/privacy/private-in-public-assoc-ty.stderr
index 6740277c9a7c1..0e5dab1a08c37 100644
--- a/src/test/ui/privacy/private-in-public-assoc-ty.stderr
+++ b/src/test/ui/privacy/private-in-public-assoc-ty.stderr
@@ -6,7 +6,7 @@ LL | |         //~^ WARN private trait `m::PrivTr` in public interface
 LL | |         //~| WARN this was previously accepted
 LL | |         //~| WARN private type `m::Priv` in public interface
 ...  |
-LL | |         //~^ ERROR private type `m::Priv` in public interface
+LL | |         fn infer_exist() -> Self::Exist;
 LL | |     }
    | |_____^
    |
@@ -22,7 +22,7 @@ LL | |         //~^ WARN private trait `m::PrivTr` in public interface
 LL | |         //~| WARN this was previously accepted
 LL | |         //~| WARN private type `m::Priv` in public interface
 ...  |
-LL | |         //~^ ERROR private type `m::Priv` in public interface
+LL | |         fn infer_exist() -> Self::Exist;
 LL | |     }
    | |_____^
    |
@@ -39,7 +39,7 @@ LL |         type Alias4 = Priv;
    |         ^^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error[E0446]: private type `m::Priv` in public interface
-  --> $DIR/private-in-public-assoc-ty.rs:28:9
+  --> $DIR/private-in-public-assoc-ty.rs:31:9
    |
 LL |     struct Priv;
    |     - `m::Priv` declared as private
@@ -47,6 +47,16 @@ LL |     struct Priv;
 LL |         type Alias1 = Priv;
    |         ^^^^^^^^^^^^^^^^^^^ can't leak private type
 
-error: aborting due to 2 previous errors
+error[E0445]: private trait `m::PrivTr` in public interface
+  --> $DIR/private-in-public-assoc-ty.rs:34:9
+   |
+LL |     trait PrivTr {}
+   |     - `m::PrivTr` declared as private
+...
+LL |         existential type Exist: PrivTr;
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ can't leak private trait
+
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0446`.
+Some errors occurred: E0445, E0446.
+For more information about an error, try `rustc --explain E0445`.
diff --git a/src/test/ui/privacy/private-in-public-existential.rs b/src/test/ui/privacy/private-in-public-existential.rs
index 95658f45df6f5..61c6130e47019 100644
--- a/src/test/ui/privacy/private-in-public-existential.rs
+++ b/src/test/ui/privacy/private-in-public-existential.rs
@@ -12,4 +12,14 @@ fn check() -> Pub {
     Priv
 }
 
+pub trait Trait {
+    type Pub: Default;
+    fn method() -> Self::Pub;
+}
+
+impl Trait for u8 {
+    existential type Pub: Default;
+    fn method() -> Self::Pub { Priv }
+}
+
 fn main() {}
diff --git a/src/test/ui/privacy/private-in-public-warn.rs b/src/test/ui/privacy/private-in-public-warn.rs
index 29f365b69be4d..467b83746702b 100644
--- a/src/test/ui/privacy/private-in-public-warn.rs
+++ b/src/test/ui/privacy/private-in-public-warn.rs
@@ -49,6 +49,7 @@ mod traits {
 
     pub type Alias<T: PrivTr> = T; //~ ERROR private trait `traits::PrivTr` in public interface
     //~| WARNING hard error
+    //~| WARNING bounds on generic parameters are not enforced in type aliases
     pub trait Tr1: PrivTr {} //~ ERROR private trait `traits::PrivTr` in public interface
     //~^ WARNING hard error
     pub trait Tr2<T: PrivTr> {} //~ ERROR private trait `traits::PrivTr` in public interface
@@ -74,6 +75,7 @@ mod traits_where {
     pub type Alias<T> where T: PrivTr = T;
         //~^ ERROR private trait `traits_where::PrivTr` in public interface
         //~| WARNING hard error
+        //~| WARNING where clauses are not enforced in type aliases
     pub trait Tr2<T> where T: PrivTr {}
         //~^ ERROR private trait `traits_where::PrivTr` in public interface
         //~| WARNING hard error
diff --git a/src/test/ui/privacy/private-in-public-warn.stderr b/src/test/ui/privacy/private-in-public-warn.stderr
index 8f9e7cd74f992..621d9a57fa076 100644
--- a/src/test/ui/privacy/private-in-public-warn.stderr
+++ b/src/test/ui/privacy/private-in-public-warn.stderr
@@ -112,7 +112,7 @@ LL |     pub type Alias<T: PrivTr> = T; //~ ERROR private trait `traits::PrivTr`
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:52:5
+  --> $DIR/private-in-public-warn.rs:53:5
    |
 LL |     pub trait Tr1: PrivTr {} //~ ERROR private trait `traits::PrivTr` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^
@@ -121,7 +121,7 @@ LL |     pub trait Tr1: PrivTr {} //~ ERROR private trait `traits::PrivTr` in pu
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:54:5
+  --> $DIR/private-in-public-warn.rs:55:5
    |
 LL |     pub trait Tr2<T: PrivTr> {} //~ ERROR private trait `traits::PrivTr` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -130,7 +130,7 @@ LL |     pub trait Tr2<T: PrivTr> {} //~ ERROR private trait `traits::PrivTr` in
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:56:5
+  --> $DIR/private-in-public-warn.rs:57:5
    |
 LL | /     pub trait Tr3 {
 LL | |         //~^ ERROR private trait `traits::PrivTr` in public interface
@@ -145,7 +145,7 @@ LL | |     }
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:60:9
+  --> $DIR/private-in-public-warn.rs:61:9
    |
 LL |         fn f<T: PrivTr>(arg: T) {} //~ ERROR private trait `traits::PrivTr` in public interface
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -154,7 +154,7 @@ LL |         fn f<T: PrivTr>(arg: T) {} //~ ERROR private trait `traits::PrivTr`
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:63:5
+  --> $DIR/private-in-public-warn.rs:64:5
    |
 LL |     impl<T: PrivTr> Pub<T> {} //~ ERROR private trait `traits::PrivTr` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -163,7 +163,7 @@ LL |     impl<T: PrivTr> Pub<T> {} //~ ERROR private trait `traits::PrivTr` in p
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:65:5
+  --> $DIR/private-in-public-warn.rs:66:5
    |
 LL |     impl<T: PrivTr> PubTr for Pub<T> {} //~ ERROR private trait `traits::PrivTr` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -172,7 +172,7 @@ LL |     impl<T: PrivTr> PubTr for Pub<T> {} //~ ERROR private trait `traits::Pr
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits_where::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:74:5
+  --> $DIR/private-in-public-warn.rs:75:5
    |
 LL |     pub type Alias<T> where T: PrivTr = T;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -181,7 +181,7 @@ LL |     pub type Alias<T> where T: PrivTr = T;
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits_where::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:77:5
+  --> $DIR/private-in-public-warn.rs:79:5
    |
 LL |     pub trait Tr2<T> where T: PrivTr {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -190,7 +190,7 @@ LL |     pub trait Tr2<T> where T: PrivTr {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits_where::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:81:9
+  --> $DIR/private-in-public-warn.rs:83:9
    |
 LL |         fn f<T>(arg: T) where T: PrivTr {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -199,7 +199,7 @@ LL |         fn f<T>(arg: T) where T: PrivTr {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits_where::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:85:5
+  --> $DIR/private-in-public-warn.rs:87:5
    |
 LL |     impl<T> Pub<T> where T: PrivTr {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -208,7 +208,7 @@ LL |     impl<T> Pub<T> where T: PrivTr {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `traits_where::PrivTr` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:88:5
+  --> $DIR/private-in-public-warn.rs:90:5
    |
 LL |     impl<T> PubTr for Pub<T> where T: PrivTr {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -217,7 +217,7 @@ LL |     impl<T> PubTr for Pub<T> where T: PrivTr {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `generics::PrivTr<generics::Pub>` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:99:5
+  --> $DIR/private-in-public-warn.rs:101:5
    |
 LL |     pub trait Tr1: PrivTr<Pub> {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -226,7 +226,7 @@ LL |     pub trait Tr1: PrivTr<Pub> {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private type `generics::Priv` in public interface (error E0446)
-  --> $DIR/private-in-public-warn.rs:102:5
+  --> $DIR/private-in-public-warn.rs:104:5
    |
 LL |     pub trait Tr2: PubTr<Priv> {} //~ ERROR private type `generics::Priv` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -235,7 +235,7 @@ LL |     pub trait Tr2: PubTr<Priv> {} //~ ERROR private type `generics::Priv` i
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private type `generics::Priv` in public interface (error E0446)
-  --> $DIR/private-in-public-warn.rs:104:5
+  --> $DIR/private-in-public-warn.rs:106:5
    |
 LL |     pub trait Tr3: PubTr<[Priv; 1]> {} //~ ERROR private type `generics::Priv` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -244,7 +244,7 @@ LL |     pub trait Tr3: PubTr<[Priv; 1]> {} //~ ERROR private type `generics::Pr
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private type `generics::Priv` in public interface (error E0446)
-  --> $DIR/private-in-public-warn.rs:106:5
+  --> $DIR/private-in-public-warn.rs:108:5
    |
 LL |     pub trait Tr4: PubTr<Pub<Priv>> {} //~ ERROR private type `generics::Priv` in public interface
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -253,7 +253,7 @@ LL |     pub trait Tr4: PubTr<Pub<Priv>> {} //~ ERROR private type `generics::Pr
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error[E0446]: private type `impls::Priv` in public interface
-  --> $DIR/private-in-public-warn.rs:133:9
+  --> $DIR/private-in-public-warn.rs:135:9
    |
 LL |     struct Priv;
    |     - `impls::Priv` declared as private
@@ -262,7 +262,7 @@ LL |         type Alias = Priv; //~ ERROR private type `impls::Priv` in public i
    |         ^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error: private type `aliases_pub::Priv` in public interface (error E0446)
-  --> $DIR/private-in-public-warn.rs:204:9
+  --> $DIR/private-in-public-warn.rs:206:9
    |
 LL |         pub fn f(arg: Priv) {} //~ ERROR private type `aliases_pub::Priv` in public interface
    |         ^^^^^^^^^^^^^^^^^^^^^^
@@ -271,7 +271,7 @@ LL |         pub fn f(arg: Priv) {} //~ ERROR private type `aliases_pub::Priv` i
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error[E0446]: private type `aliases_pub::Priv` in public interface
-  --> $DIR/private-in-public-warn.rs:208:9
+  --> $DIR/private-in-public-warn.rs:210:9
    |
 LL |     struct Priv;
    |     - `aliases_pub::Priv` declared as private
@@ -280,7 +280,7 @@ LL |         type Check = Priv; //~ ERROR private type `aliases_pub::Priv` in pu
    |         ^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error[E0446]: private type `aliases_pub::Priv` in public interface
-  --> $DIR/private-in-public-warn.rs:211:9
+  --> $DIR/private-in-public-warn.rs:213:9
    |
 LL |     struct Priv;
    |     - `aliases_pub::Priv` declared as private
@@ -289,7 +289,7 @@ LL |         type Check = Priv; //~ ERROR private type `aliases_pub::Priv` in pu
    |         ^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error[E0446]: private type `aliases_pub::Priv` in public interface
-  --> $DIR/private-in-public-warn.rs:214:9
+  --> $DIR/private-in-public-warn.rs:216:9
    |
 LL |     struct Priv;
    |     - `aliases_pub::Priv` declared as private
@@ -298,7 +298,7 @@ LL |         type Check = Priv; //~ ERROR private type `aliases_pub::Priv` in pu
    |         ^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error[E0446]: private type `aliases_pub::Priv` in public interface
-  --> $DIR/private-in-public-warn.rs:217:9
+  --> $DIR/private-in-public-warn.rs:219:9
    |
 LL |     struct Priv;
    |     - `aliases_pub::Priv` declared as private
@@ -307,7 +307,7 @@ LL |         type Check = Priv; //~ ERROR private type `aliases_pub::Priv` in pu
    |         ^^^^^^^^^^^^^^^^^^ can't leak private type
 
 error: private trait `aliases_priv::PrivTr1` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:247:5
+  --> $DIR/private-in-public-warn.rs:249:5
    |
 LL |     pub trait Tr1: PrivUseAliasTr {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -316,7 +316,7 @@ LL |     pub trait Tr1: PrivUseAliasTr {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private trait `aliases_priv::PrivTr1<aliases_priv::Priv2>` in public interface (error E0445)
-  --> $DIR/private-in-public-warn.rs:250:5
+  --> $DIR/private-in-public-warn.rs:252:5
    |
 LL |     pub trait Tr2: PrivUseAliasTr<PrivAlias> {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -325,7 +325,7 @@ LL |     pub trait Tr2: PrivUseAliasTr<PrivAlias> {}
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
 error: private type `aliases_priv::Priv2` in public interface (error E0446)
-  --> $DIR/private-in-public-warn.rs:250:5
+  --> $DIR/private-in-public-warn.rs:252:5
    |
 LL |     pub trait Tr2: PrivUseAliasTr<PrivAlias> {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -333,6 +333,23 @@ LL |     pub trait Tr2: PrivUseAliasTr<PrivAlias> {}
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
 
+warning: bounds on generic parameters are not enforced in type aliases
+  --> $DIR/private-in-public-warn.rs:50:23
+   |
+LL |     pub type Alias<T: PrivTr> = T; //~ ERROR private trait `traits::PrivTr` in public interface
+   |                       ^^^^^^
+   |
+   = note: #[warn(type_alias_bounds)] on by default
+   = help: the bound will not be checked when the type alias is used, and should be removed
+
+warning: where clauses are not enforced in type aliases
+  --> $DIR/private-in-public-warn.rs:75:29
+   |
+LL |     pub type Alias<T> where T: PrivTr = T;
+   |                             ^^^^^^^^^
+   |
+   = help: the clause will not be checked when the type alias is used, and should be removed
+
 error: aborting due to 36 previous errors
 
 For more information about this error, try `rustc --explain E0446`.
diff --git a/src/test/ui/privacy/private-inferred-type.rs b/src/test/ui/privacy/private-inferred-type.rs
index 69b60a56c67f1..d98cf5991efeb 100644
--- a/src/test/ui/privacy/private-inferred-type.rs
+++ b/src/test/ui/privacy/private-inferred-type.rs
@@ -1,4 +1,3 @@
-#![feature(associated_consts)]
 #![feature(decl_macro)]
 #![allow(private_in_public)]
 
@@ -15,6 +14,7 @@ mod m {
     pub struct PubTupleStruct(u8);
     impl PubTupleStruct { fn method() {} }
 
+    #[derive(Clone, Copy)]
     struct Priv;
     pub type Alias = Priv;
     pub struct Pub<T = Alias>(pub T);
diff --git a/src/test/ui/privacy/pub-priv-dep/auxiliary/priv_dep.rs b/src/test/ui/privacy/pub-priv-dep/auxiliary/priv_dep.rs
new file mode 100644
index 0000000000000..e7afeb84fb4f4
--- /dev/null
+++ b/src/test/ui/privacy/pub-priv-dep/auxiliary/priv_dep.rs
@@ -0,0 +1,2 @@
+pub struct OtherType;
+pub trait OtherTrait {}
diff --git a/src/test/ui/privacy/pub-priv-dep/auxiliary/pub_dep.rs b/src/test/ui/privacy/pub-priv-dep/auxiliary/pub_dep.rs
new file mode 100644
index 0000000000000..3ebafd953addf
--- /dev/null
+++ b/src/test/ui/privacy/pub-priv-dep/auxiliary/pub_dep.rs
@@ -0,0 +1 @@
+pub struct PubType;
diff --git a/src/test/ui/privacy/pub-priv-dep/pub-priv1.rs b/src/test/ui/privacy/pub-priv-dep/pub-priv1.rs
new file mode 100644
index 0000000000000..9ebc96017fe9c
--- /dev/null
+++ b/src/test/ui/privacy/pub-priv-dep/pub-priv1.rs
@@ -0,0 +1,46 @@
+ // aux-build:priv_dep.rs
+ // aux-build:pub_dep.rs
+ // compile-flags: --extern-private priv_dep
+#![deny(exported_private_dependencies)]
+
+// This crate is a private dependency
+extern crate priv_dep;
+// This crate is a public dependenct
+extern crate pub_dep;
+
+use priv_dep::{OtherType, OtherTrait};
+use pub_dep::PubType;
+
+// Type from private dependency used in private
+// type - this is fine
+struct PrivateType {
+    field: OtherType
+}
+
+pub struct PublicType {
+    pub field: OtherType,
+    //~^ ERROR type `priv_dep::OtherType` from private dependency 'priv_dep' in public interface
+    priv_field: OtherType, // Private field - this is fine
+    pub other_field: PubType // Type from public dependency - this is fine
+}
+
+impl PublicType {
+    pub fn pub_fn(param: OtherType) {}
+    //~^ ERROR type `priv_dep::OtherType` from private dependency 'priv_dep' in public interface
+
+    fn priv_fn(param: OtherType) {}
+}
+
+pub trait MyPubTrait {
+    type Foo: OtherTrait;
+}
+//~^^^ ERROR trait `priv_dep::OtherTrait` from private dependency 'priv_dep' in public interface
+
+pub struct AllowedPrivType {
+    #[allow(exported_private_dependencies)]
+    pub allowed: OtherType
+}
+
+
+
+fn main() {}
diff --git a/src/test/ui/privacy/pub-priv-dep/pub-priv1.stderr b/src/test/ui/privacy/pub-priv-dep/pub-priv1.stderr
new file mode 100644
index 0000000000000..b31efdbd781dc
--- /dev/null
+++ b/src/test/ui/privacy/pub-priv-dep/pub-priv1.stderr
@@ -0,0 +1,28 @@
+error: type `priv_dep::OtherType` from private dependency 'priv_dep' in public interface
+  --> $DIR/pub-priv1.rs:21:5
+   |
+LL |     pub field: OtherType,
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+note: lint level defined here
+  --> $DIR/pub-priv1.rs:4:9
+   |
+LL | #![deny(exported_private_dependencies)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: type `priv_dep::OtherType` from private dependency 'priv_dep' in public interface
+  --> $DIR/pub-priv1.rs:28:5
+   |
+LL |     pub fn pub_fn(param: OtherType) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: trait `priv_dep::OtherTrait` from private dependency 'priv_dep' in public interface
+  --> $DIR/pub-priv1.rs:34:1
+   |
+LL | / pub trait MyPubTrait {
+LL | |     type Foo: OtherTrait;
+LL | | }
+   | |_^
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/privacy/pub-priv-dep/std-pub.rs b/src/test/ui/privacy/pub-priv-dep/std-pub.rs
new file mode 100644
index 0000000000000..e25aa93a02e60
--- /dev/null
+++ b/src/test/ui/privacy/pub-priv-dep/std-pub.rs
@@ -0,0 +1,12 @@
+// The 'std' crates should always be implicitly public,
+// without having to pass any compiler arguments
+
+// run-pass
+
+#![deny(exported_private_dependencies)]
+
+pub struct PublicType {
+    pub field: Option<u8>
+}
+
+fn main() {}
diff --git a/src/test/ui/proc-macro/attributes-included.stderr b/src/test/ui/proc-macro/attributes-included.stderr
index ea5be5a3be0e5..87b6fb9539fb4 100644
--- a/src/test/ui/proc-macro/attributes-included.stderr
+++ b/src/test/ui/proc-macro/attributes-included.stderr
@@ -2,7 +2,7 @@ warning: unused variable: `a`
   --> $DIR/attributes-included.rs:17:9
    |
 LL |     let a: i32 = "foo"; //~ WARN: unused variable
-   |         ^ help: consider using `_a` instead
+   |         ^ help: consider prefixing with an underscore: `_a`
    |
 note: lint level defined here
   --> $DIR/attributes-included.rs:4:9
diff --git a/src/test/ui/proc-macro/derive-still-gated.stderr b/src/test/ui/proc-macro/derive-still-gated.stderr
index d54a593f78311..ece1b6212914d 100644
--- a/src/test/ui/proc-macro/derive-still-gated.stderr
+++ b/src/test/ui/proc-macro/derive-still-gated.stderr
@@ -2,7 +2,7 @@ error[E0658]: The attribute `derive_A` is currently unknown to the compiler and
   --> $DIR/derive-still-gated.rs:8:3
    |
 LL | #[derive_A] //~ ERROR attribute `derive_A` is currently unknown
-   |   ^^^^^^^^
+   |   ^^^^^^^^ help: a built-in attribute with a similar name exists: `derive`
    |
    = help: add #![feature(custom_attribute)] to the crate attributes to enable
 
diff --git a/src/test/ui/proc-macro/shadow.stderr b/src/test/ui/proc-macro/shadow.stderr
index 103c78126a838..2dfe2a94c88e1 100644
--- a/src/test/ui/proc-macro/shadow.stderr
+++ b/src/test/ui/proc-macro/shadow.stderr
@@ -1,17 +1,16 @@
 error[E0259]: the name `derive_a` is defined multiple times
   --> $DIR/shadow.rs:6:1
    |
-LL | extern crate derive_a;
-   | ---------------------- previous import of the extern crate `derive_a` here
-LL | #[macro_use]
-LL | extern crate derive_a; //~ ERROR the name `derive_a` is defined multiple times
-   | ^^^^^^^^^^^^^^^^^^^^^^ `derive_a` reimported here
+LL |   extern crate derive_a;
+   |   ---------------------- previous import of the extern crate `derive_a` here
+LL | / #[macro_use]
+LL | | extern crate derive_a; //~ ERROR the name `derive_a` is defined multiple times
+   | | ^^^^^^^^^^^^^^^^^^^^^-
+   | |_|____________________|
+   |   |                    help: remove unnecessary import
+   |   `derive_a` reimported here
    |
    = note: `derive_a` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | extern crate derive_a as other_derive_a; //~ ERROR the name `derive_a` is defined multiple times
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/proc-macro/span-preservation.stderr b/src/test/ui/proc-macro/span-preservation.stderr
index 1f9103a6d2ee8..db524907b656f 100644
--- a/src/test/ui/proc-macro/span-preservation.stderr
+++ b/src/test/ui/proc-macro/span-preservation.stderr
@@ -15,6 +15,9 @@ LL |     let x: usize = "hello";;;;; //~ ERROR mismatched types
 error[E0308]: mismatched types
   --> $DIR/span-preservation.rs:19:29
    |
+LL | fn b(x: Option<isize>) -> usize {
+   |                           ----- expected `usize` because of return type
+LL |     match x {
 LL |         Some(x) => { return x }, //~ ERROR mismatched types
    |                             ^ expected usize, found isize
 
diff --git a/src/test/ui/quote-with-interpolated.rs b/src/test/ui/quote-with-interpolated.rs
deleted file mode 100644
index b948226652b45..0000000000000
--- a/src/test/ui/quote-with-interpolated.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-#![feature(quote)]
-fn main() {
-    macro_rules! foo {
-        ($bar:expr)  => {
-            quote_expr!(cx, $bar)
-            //~^ ERROR quote! with interpolated token
-            //~| ERROR failed to resolve: maybe a missing `extern crate syntax;`?
-            //~| ERROR failed to resolve: maybe a missing `extern crate syntax;`?
-            //~| ERROR cannot find value `cx` in this scope
-            //~| ERROR cannot find function `new_parser_from_tts` in this scope
-        }
-    }
-    foo!(bar);
-}
diff --git a/src/test/ui/quote-with-interpolated.stderr b/src/test/ui/quote-with-interpolated.stderr
deleted file mode 100644
index 96feff949bfc9..0000000000000
--- a/src/test/ui/quote-with-interpolated.stderr
+++ /dev/null
@@ -1,40 +0,0 @@
-error: quote! with interpolated token
-  --> $DIR/quote-with-interpolated.rs:5:29
-   |
-LL |             quote_expr!(cx, $bar)
-   |                             ^^^^
-...
-LL |     foo!(bar);
-   |     ---------- in this macro invocation
-
-error[E0433]: failed to resolve: maybe a missing `extern crate syntax;`?
-  --> $DIR/quote-with-interpolated.rs:5:13
-   |
-LL |             quote_expr!(cx, $bar)
-   |             ^^^^^^^^^^^^^^^^^^^^^ maybe a missing `extern crate syntax;`?
-
-error[E0433]: failed to resolve: maybe a missing `extern crate syntax;`?
-  --> $DIR/quote-with-interpolated.rs:5:29
-   |
-LL |             quote_expr!(cx, $bar)
-   |                             ^^^^ maybe a missing `extern crate syntax;`?
-
-error[E0425]: cannot find value `cx` in this scope
-  --> $DIR/quote-with-interpolated.rs:5:25
-   |
-LL |             quote_expr!(cx, $bar)
-   |                         ^^ not found in this scope
-...
-LL |     foo!(bar);
-   |     ---------- in this macro invocation
-
-error[E0425]: cannot find function `new_parser_from_tts` in this scope
-  --> $DIR/quote-with-interpolated.rs:5:13
-   |
-LL |             quote_expr!(cx, $bar)
-   |             ^^^^^^^^^^^^^^^^^^^^^ not found in this scope
-
-error: aborting due to 5 previous errors
-
-Some errors occurred: E0425, E0433.
-For more information about an error, try `rustc --explain E0425`.
diff --git a/src/test/ui/ref-suggestion.nll.stderr b/src/test/ui/ref-suggestion.nll.stderr
index 7c00461c900a2..bef8dcca921e6 100644
--- a/src/test/ui/ref-suggestion.nll.stderr
+++ b/src/test/ui/ref-suggestion.nll.stderr
@@ -1,22 +1,22 @@
 error[E0382]: use of moved value: `x`
   --> $DIR/ref-suggestion.rs:4:5
    |
+LL |     let x = vec![1];
+   |         - move occurs because `x` has type `std::vec::Vec<i32>`, which does not implement the `Copy` trait
 LL |     let y = x;
    |             - value moved here
 LL |     x; //~ ERROR use of moved value
    |     ^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::vec::Vec<i32>`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x`
   --> $DIR/ref-suggestion.rs:8:5
    |
+LL |     let x = vec![1];
+   |         - move occurs because `x` has type `std::vec::Vec<i32>`, which does not implement the `Copy` trait
 LL |     let mut y = x;
    |                 - value moved here
 LL |     x; //~ ERROR use of moved value
    |     ^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::vec::Vec<i32>`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x`
   --> $DIR/ref-suggestion.rs:16:5
diff --git a/src/test/ui/regions-fn-subtyping-return-static-fail.rs b/src/test/ui/regions-fn-subtyping-return-static-fail.rs
index 242119cc201da..2dd0c9796e258 100644
--- a/src/test/ui/regions-fn-subtyping-return-static-fail.rs
+++ b/src/test/ui/regions-fn-subtyping-return-static-fail.rs
@@ -37,7 +37,7 @@ fn baz(x: &S) -> &S {
 fn supply_F() {
     want_F(foo);
 
-    want_F(bar);
+    want_F(bar); //~ ERROR mismatched types
 
     want_F(baz);
 }
@@ -45,7 +45,7 @@ fn supply_F() {
 fn supply_G() {
     want_G(foo);
     want_G(bar);
-    want_G(baz); //~ ERROR
+    want_G(baz); //~ ERROR mismatched types
 }
 
 pub fn main() {
diff --git a/src/test/ui/regions-fn-subtyping-return-static-fail.stderr b/src/test/ui/regions-fn-subtyping-return-static-fail.stderr
index a9234e43191ea..66e6a615b33bc 100644
--- a/src/test/ui/regions-fn-subtyping-return-static-fail.stderr
+++ b/src/test/ui/regions-fn-subtyping-return-static-fail.stderr
@@ -1,12 +1,21 @@
+error[E0308]: mismatched types
+  --> $DIR/regions-fn-subtyping-return-static-fail.rs:40:12
+   |
+LL |     want_F(bar); //~ ERROR mismatched types
+   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
+   |
+   = note: expected type `for<'cx> fn(&'cx S) -> &'cx S`
+              found type `for<'a> fn(&'a S) -> &S {bar::<'_>}`
+
 error[E0308]: mismatched types
   --> $DIR/regions-fn-subtyping-return-static-fail.rs:48:12
    |
-LL |     want_G(baz); //~ ERROR
-   |            ^^^ one type is more general than the other
+LL |     want_G(baz); //~ ERROR mismatched types
+   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
    |
    = note: expected type `for<'cx> fn(&'cx S) -> &'static S`
-              found type `for<'r> fn(&'r S) -> &'r S`
+              found type `for<'r> fn(&'r S) -> &'r S {baz}`
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr b/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
index 47e1d0efdc77b..5c8b3d3ba6922 100644
--- a/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
+++ b/src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.stderr
@@ -20,10 +20,10 @@ error[E0308]: mismatched types
   --> $DIR/region-lifetime-bounds-on-fns-where-clause.rs:20:43
    |
 LL |     let _: fn(&mut &isize, &mut &isize) = a; //~ ERROR mismatched types
-   |                                           ^ one type is more general than the other
+   |                                           ^ expected concrete lifetime, found bound lifetime parameter
    |
    = note: expected type `for<'r, 's, 't0, 't1> fn(&'r mut &'s isize, &'t0 mut &'t1 isize)`
-              found type `for<'r, 's> fn(&'r mut &isize, &'s mut &isize)`
+              found type `for<'r, 's> fn(&'r mut &isize, &'s mut &isize) {a::<'_, '_>}`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr b/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
index 1e7b99053f77f..f36885f7aeb99 100644
--- a/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
+++ b/src/test/ui/regions/region-multiple-lifetime-bounds-on-fns-where-clause.stderr
@@ -31,10 +31,10 @@ error[E0308]: mismatched types
   --> $DIR/region-multiple-lifetime-bounds-on-fns-where-clause.rs:22:56
    |
 LL |     let _: fn(&mut &isize, &mut &isize, &mut &isize) = a; //~ ERROR E0308
-   |                                                        ^ one type is more general than the other
+   |                                                        ^ expected concrete lifetime, found bound lifetime parameter
    |
    = note: expected type `for<'r, 's, 't0, 't1, 't2, 't3> fn(&'r mut &'s isize, &'t0 mut &'t1 isize, &'t2 mut &'t3 isize)`
-              found type `for<'r, 's, 't0> fn(&'r mut &isize, &'s mut &isize, &'t0 mut &isize)`
+              found type `for<'r, 's, 't0> fn(&'r mut &isize, &'s mut &isize, &'t0 mut &isize) {a::<'_, '_, '_>}`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.ast.stderr b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.ast.stderr
new file mode 100644
index 0000000000000..76ead4e94ef66
--- /dev/null
+++ b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.ast.stderr
@@ -0,0 +1,20 @@
+error[E0491]: in type `&'a WithAssoc<TheType<'b>>`, reference has a longer lifetime than the data it references
+  --> $DIR/regions-assoc-type-in-supertrait-outlives-container.rs:45:13
+   |
+LL |     let _x: &'a WithAssoc<TheType<'b>> = loop { };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the pointer is valid for the lifetime 'a as defined on the function body at 37:15
+  --> $DIR/regions-assoc-type-in-supertrait-outlives-container.rs:37:15
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               ^^
+note: but the referenced data is only valid for the lifetime 'b as defined on the function body at 37:18
+  --> $DIR/regions-assoc-type-in-supertrait-outlives-container.rs:37:18
+   |
+LL | fn with_assoc<'a,'b>() {
+   |                  ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0491`.
diff --git a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.mir.stderr b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.mir.stderr
new file mode 100644
index 0000000000000..ad94d375b5bb7
--- /dev/null
+++ b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.mir.stderr
@@ -0,0 +1,13 @@
+error: lifetime may not live long enough
+  --> $DIR/regions-assoc-type-in-supertrait-outlives-container.rs:45:13
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               -- -- lifetime `'b` defined here
+   |               |
+   |               lifetime `'a` defined here
+...
+LL |     let _x: &'a WithAssoc<TheType<'b>> = loop { };
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.rs b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.rs
index df7c1e0c7c78b..1d53492199230 100644
--- a/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.rs
+++ b/src/test/ui/regions/regions-assoc-type-in-supertrait-outlives-container.rs
@@ -3,6 +3,9 @@
 // outlive the location in which the type appears, even when the
 // associted type is in a supertype. Issue #22246.
 
+// revisions: ast mir
+//[mir]compile-flags: -Z borrowck=mir
+
 #![allow(dead_code)]
 
 ///////////////////////////////////////////////////////////////////////////
@@ -40,7 +43,8 @@ fn with_assoc<'a,'b>() {
     // FIXME (#54943) NLL doesn't enforce WF condition in unreachable code if
     // `_x` is changed to `_`
     let _x: &'a WithAssoc<TheType<'b>> = loop { };
-    //~^ ERROR reference has a longer lifetime
+    //[ast]~^ ERROR reference has a longer lifetime
+    //[mir]~^^ ERROR lifetime may not live long enough
 }
 
 fn main() {
diff --git a/src/test/ui/regions/regions-fn-subtyping-return-static.rs b/src/test/ui/regions/regions-fn-subtyping-return-static.rs
index 9010770f1dc82..fa2cc37d05b2b 100644
--- a/src/test/ui/regions/regions-fn-subtyping-return-static.rs
+++ b/src/test/ui/regions/regions-fn-subtyping-return-static.rs
@@ -5,8 +5,6 @@
 // *ANY* lifetime and returns a reference with the 'static lifetime.
 // This can safely be considered to be an instance of `F` because all
 // lifetimes are sublifetimes of 'static.
-//
-// compile-pass
 
 #![allow(dead_code)]
 #![allow(unused_variables)]
@@ -40,7 +38,7 @@ fn baz(x: &S) -> &S {
 fn supply_F() {
     want_F(foo);
 
-    want_F(bar);
+    want_F(bar); //~ ERROR mismatched types
 
     want_F(baz);
 }
diff --git a/src/test/ui/regions/regions-fn-subtyping-return-static.stderr b/src/test/ui/regions/regions-fn-subtyping-return-static.stderr
new file mode 100644
index 0000000000000..42a5a7c806e08
--- /dev/null
+++ b/src/test/ui/regions/regions-fn-subtyping-return-static.stderr
@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/regions-fn-subtyping-return-static.rs:41:12
+   |
+LL |     want_F(bar); //~ ERROR mismatched types
+   |            ^^^ expected concrete lifetime, found bound lifetime parameter 'cx
+   |
+   = note: expected type `for<'cx> fn(&'cx S) -> &'cx S`
+              found type `for<'a> fn(&'a S) -> &S {bar::<'_>}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/regions/regions-free-region-ordering-caller.ast.stderr b/src/test/ui/regions/regions-free-region-ordering-caller.ast.stderr
new file mode 100644
index 0000000000000..73266ab50fad0
--- /dev/null
+++ b/src/test/ui/regions/regions-free-region-ordering-caller.ast.stderr
@@ -0,0 +1,32 @@
+error[E0623]: lifetime mismatch
+  --> $DIR/regions-free-region-ordering-caller.rs:11:12
+   |
+LL | fn call2<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |                     ---------     ---------
+   |                     |
+   |                     these two types are declared with different lifetimes...
+LL |     let z: Option<&'b &'a usize> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^ ...but data from `a` flows into `b` here
+
+error[E0623]: lifetime mismatch
+  --> $DIR/regions-free-region-ordering-caller.rs:17:12
+   |
+LL | fn call3<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |                     ---------     ---------
+   |                     |
+   |                     these two types are declared with different lifetimes...
+LL |     let y: Paramd<'a> = Paramd { x: a };
+LL |     let z: Option<&'b Paramd<'a>> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^^ ...but data from `a` flows into `b` here
+
+error[E0623]: lifetime mismatch
+  --> $DIR/regions-free-region-ordering-caller.rs:22:12
+   |
+LL | fn call4<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |                     ---------     --------- these two types are declared with different lifetimes...
+LL |     let z: Option<&'a &'b usize> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^ ...but data from `b` flows into `a` here
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0623`.
diff --git a/src/test/ui/regions/regions-free-region-ordering-caller.mir.stderr b/src/test/ui/regions/regions-free-region-ordering-caller.mir.stderr
new file mode 100644
index 0000000000000..abec468c9ea3e
--- /dev/null
+++ b/src/test/ui/regions/regions-free-region-ordering-caller.mir.stderr
@@ -0,0 +1,33 @@
+error: lifetime may not live long enough
+  --> $DIR/regions-free-region-ordering-caller.rs:11:12
+   |
+LL | fn call2<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |          --  -- lifetime `'b` defined here
+   |          |
+   |          lifetime `'a` defined here
+LL |     let z: Option<&'b &'a usize> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/regions-free-region-ordering-caller.rs:17:12
+   |
+LL | fn call3<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |          --  -- lifetime `'b` defined here
+   |          |
+   |          lifetime `'a` defined here
+LL |     let y: Paramd<'a> = Paramd { x: a };
+LL |     let z: Option<&'b Paramd<'a>> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'b`
+
+error: lifetime may not live long enough
+  --> $DIR/regions-free-region-ordering-caller.rs:22:12
+   |
+LL | fn call4<'a, 'b>(a: &'a usize, b: &'b usize) {
+   |          --  -- lifetime `'b` defined here
+   |          |
+   |          lifetime `'a` defined here
+LL |     let z: Option<&'a &'b usize> = None;//[ast]~ ERROR E0623
+   |            ^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/regions/regions-free-region-ordering-caller.rs b/src/test/ui/regions/regions-free-region-ordering-caller.rs
index e26799fcc4711..621e6e78b4650 100644
--- a/src/test/ui/regions/regions-free-region-ordering-caller.rs
+++ b/src/test/ui/regions/regions-free-region-ordering-caller.rs
@@ -2,19 +2,25 @@
 // than the thing it points at and ensure that they result in
 // errors. See also regions-free-region-ordering-callee.rs
 
+// revisions: ast mir
+//[mir]compile-flags: -Z borrowck=mir
+
 struct Paramd<'a> { x: &'a usize }
 
 fn call2<'a, 'b>(a: &'a usize, b: &'b usize) {
-    let z: Option<&'b &'a usize> = None;//~ ERROR E0623
+    let z: Option<&'b &'a usize> = None;//[ast]~ ERROR E0623
+    //[mir]~^ ERROR lifetime may not live long enough
 }
 
 fn call3<'a, 'b>(a: &'a usize, b: &'b usize) {
     let y: Paramd<'a> = Paramd { x: a };
-    let z: Option<&'b Paramd<'a>> = None;//~ ERROR E0623
+    let z: Option<&'b Paramd<'a>> = None;//[ast]~ ERROR E0623
+    //[mir]~^ ERROR lifetime may not live long enough
 }
 
 fn call4<'a, 'b>(a: &'a usize, b: &'b usize) {
-    let z: Option<&'a &'b usize> = None;//~ ERROR E0623
+    let z: Option<&'a &'b usize> = None;//[ast]~ ERROR E0623
+    //[mir]~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/src/test/ui/regions/regions-free-region-ordering-caller1.nll.stderr b/src/test/ui/regions/regions-free-region-ordering-caller1.nll.stderr
index 92c21fcb4aec5..539343a68294f 100644
--- a/src/test/ui/regions/regions-free-region-ordering-caller1.nll.stderr
+++ b/src/test/ui/regions/regions-free-region-ordering-caller1.nll.stderr
@@ -12,6 +12,21 @@ LL |     let z: &'a & usize = &(&y);
 LL | }
    | - temporary value is freed at the end of this statement
 
-error: aborting due to previous error
+error[E0597]: `y` does not live long enough
+  --> $DIR/regions-free-region-ordering-caller1.rs:9:27
+   |
+LL | fn call1<'a>(x: &'a usize) {
+   |          -- lifetime `'a` defined here
+...
+LL |     let z: &'a & usize = &(&y);
+   |            -----------    ^^^^ borrowed value does not live long enough
+   |            |
+   |            type annotation requires that `y` is borrowed for `'a`
+...
+LL | }
+   | - `y` dropped here while still borrowed
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0716`.
+Some errors occurred: E0597, E0716.
+For more information about an error, try `rustc --explain E0597`.
diff --git a/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr b/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
index a43ee7ec3ace0..99d85e9e4b5a6 100644
--- a/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
+++ b/src/test/ui/regions/regions-lifetime-bounds-on-fns.stderr
@@ -20,10 +20,10 @@ error[E0308]: mismatched types
   --> $DIR/regions-lifetime-bounds-on-fns.rs:20:43
    |
 LL |     let _: fn(&mut &isize, &mut &isize) = a; //~ ERROR E0308
-   |                                           ^ one type is more general than the other
+   |                                           ^ expected concrete lifetime, found bound lifetime parameter
    |
    = note: expected type `for<'r, 's, 't0, 't1> fn(&'r mut &'s isize, &'t0 mut &'t1 isize)`
-              found type `for<'r, 's> fn(&'r mut &isize, &'s mut &isize)`
+              found type `for<'r, 's> fn(&'r mut &isize, &'s mut &isize) {a::<'_, '_>}`
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/regions/regions-outlives-projection-container-hrtb.ast.stderr b/src/test/ui/regions/regions-outlives-projection-container-hrtb.ast.stderr
new file mode 100644
index 0000000000000..d83301840088d
--- /dev/null
+++ b/src/test/ui/regions/regions-outlives-projection-container-hrtb.ast.stderr
@@ -0,0 +1,37 @@
+error[E0491]: in type `&'a WithHrAssoc<TheType<'b>>`, reference has a longer lifetime than the data it references
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:35:12
+   |
+LL |     let _: &'a WithHrAssoc<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the pointer is valid for the lifetime 'a as defined on the function body at 32:15
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:32:15
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               ^^
+note: but the referenced data is only valid for the lifetime 'b as defined on the function body at 32:18
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:32:18
+   |
+LL | fn with_assoc<'a,'b>() {
+   |                  ^^
+
+error[E0491]: in type `&'a WithHrAssocSub<TheType<'b>>`, reference has a longer lifetime than the data it references
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:57:12
+   |
+LL |     let _: &'a WithHrAssocSub<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the pointer is valid for the lifetime 'a as defined on the function body at 53:19
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:53:19
+   |
+LL | fn with_assoc_sub<'a,'b>() {
+   |                   ^^
+note: but the referenced data is only valid for the lifetime 'b as defined on the function body at 53:22
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:53:22
+   |
+LL | fn with_assoc_sub<'a,'b>() {
+   |                      ^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0491`.
diff --git a/src/test/ui/regions/regions-outlives-projection-container-hrtb.mir.stderr b/src/test/ui/regions/regions-outlives-projection-container-hrtb.mir.stderr
new file mode 100644
index 0000000000000..5028663ba6d04
--- /dev/null
+++ b/src/test/ui/regions/regions-outlives-projection-container-hrtb.mir.stderr
@@ -0,0 +1,24 @@
+error: lifetime may not live long enough
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:35:12
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               -- -- lifetime `'b` defined here
+   |               |
+   |               lifetime `'a` defined here
+...
+LL |     let _: &'a WithHrAssoc<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+
+error: lifetime may not live long enough
+  --> $DIR/regions-outlives-projection-container-hrtb.rs:57:12
+   |
+LL | fn with_assoc_sub<'a,'b>() {
+   |                   -- -- lifetime `'b` defined here
+   |                   |
+   |                   lifetime `'a` defined here
+...
+LL |     let _: &'a WithHrAssocSub<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/regions/regions-outlives-projection-container-hrtb.rs b/src/test/ui/regions/regions-outlives-projection-container-hrtb.rs
index 3483f24ecbf66..2871d962c42c9 100644
--- a/src/test/ui/regions/regions-outlives-projection-container-hrtb.rs
+++ b/src/test/ui/regions/regions-outlives-projection-container-hrtb.rs
@@ -1,6 +1,9 @@
 // Test that structs with higher-ranked where clauses don't generate
 // "outlives" requirements. Issue #22246.
 
+// revisions: ast mir
+//[mir]compile-flags: -Z borrowck=mir
+
 #![allow(dead_code)]
 
 
@@ -30,7 +33,8 @@ fn with_assoc<'a,'b>() {
     // We get an error because 'b:'a does not hold:
 
     let _: &'a WithHrAssoc<TheType<'b>> = loop { };
-    //~^ ERROR reference has a longer lifetime
+    //[ast]~^ ERROR reference has a longer lifetime
+    //[mir]~^^ ERROR lifetime may not live long enough
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -51,7 +55,8 @@ fn with_assoc_sub<'a,'b>() {
     // below to be well-formed, it is not related to the HR relation.
 
     let _: &'a WithHrAssocSub<TheType<'b>> = loop { };
-    //~^ ERROR reference has a longer lifetime
+    //[ast]~^ ERROR reference has a longer lifetime
+    //[mir]~^^ ERROR lifetime may not live long enough
 }
 
 
diff --git a/src/test/ui/regions/regions-outlives-projection-container-wc.ast.stderr b/src/test/ui/regions/regions-outlives-projection-container-wc.ast.stderr
new file mode 100644
index 0000000000000..9e31065ca4eec
--- /dev/null
+++ b/src/test/ui/regions/regions-outlives-projection-container-wc.ast.stderr
@@ -0,0 +1,20 @@
+error[E0491]: in type `&'a WithAssoc<TheType<'b>>`, reference has a longer lifetime than the data it references
+  --> $DIR/regions-outlives-projection-container-wc.rs:37:12
+   |
+LL |     let _: &'a WithAssoc<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: the pointer is valid for the lifetime 'a as defined on the function body at 31:15
+  --> $DIR/regions-outlives-projection-container-wc.rs:31:15
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               ^^
+note: but the referenced data is only valid for the lifetime 'b as defined on the function body at 31:18
+  --> $DIR/regions-outlives-projection-container-wc.rs:31:18
+   |
+LL | fn with_assoc<'a,'b>() {
+   |                  ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0491`.
diff --git a/src/test/ui/regions/regions-outlives-projection-container-wc.mir.stderr b/src/test/ui/regions/regions-outlives-projection-container-wc.mir.stderr
new file mode 100644
index 0000000000000..880fe17b740e4
--- /dev/null
+++ b/src/test/ui/regions/regions-outlives-projection-container-wc.mir.stderr
@@ -0,0 +1,13 @@
+error: lifetime may not live long enough
+  --> $DIR/regions-outlives-projection-container-wc.rs:37:12
+   |
+LL | fn with_assoc<'a,'b>() {
+   |               -- -- lifetime `'b` defined here
+   |               |
+   |               lifetime `'a` defined here
+...
+LL |     let _: &'a WithAssoc<TheType<'b>> = loop { };
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'b` must outlive `'a`
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/regions/regions-outlives-projection-container-wc.rs b/src/test/ui/regions/regions-outlives-projection-container-wc.rs
index 91a0d8590ff34..37622211327c0 100644
--- a/src/test/ui/regions/regions-outlives-projection-container-wc.rs
+++ b/src/test/ui/regions/regions-outlives-projection-container-wc.rs
@@ -3,6 +3,9 @@
 // outlive the location in which the type appears, even when the
 // constraint is in a where clause not a bound. Issue #22246.
 
+// revisions: ast mir
+//[mir]compile-flags: -Z borrowck=mir
+
 #![allow(dead_code)]
 
 ///////////////////////////////////////////////////////////////////////////
@@ -32,7 +35,8 @@ fn with_assoc<'a,'b>() {
     // which is &'b (), must outlive 'a.
 
     let _: &'a WithAssoc<TheType<'b>> = loop { };
-    //~^ ERROR reference has a longer lifetime
+    //[ast]~^ ERROR reference has a longer lifetime
+    //[mir]~^^ ERROR lifetime may not live long enough
 }
 
 fn main() {
diff --git a/src/test/ui/regions/regions-static-bound.nll.stderr b/src/test/ui/regions/regions-static-bound.nll.stderr
index f667afdef7fa7..d6cec03e0ff2e 100644
--- a/src/test/ui/regions/regions-static-bound.nll.stderr
+++ b/src/test/ui/regions/regions-static-bound.nll.stderr
@@ -1,4 +1,4 @@
-error: unsatisfied lifetime constraints
+error: lifetime may not live long enough
   --> $DIR/regions-static-bound.rs:9:5
    |
 LL | fn static_id_wrong_way<'a>(t: &'a ()) -> &'static () where 'static: 'a {
diff --git a/src/test/ui/regions/regions-static-bound.rs b/src/test/ui/regions/regions-static-bound.rs
index 3ee518702e064..c1a15e50a4d06 100644
--- a/src/test/ui/regions/regions-static-bound.rs
+++ b/src/test/ui/regions/regions-static-bound.rs
@@ -7,7 +7,7 @@ fn static_id_indirect<'a,'b>(t: &'a ()) -> &'static ()
     where 'a: 'b, 'b: 'static { t }
 fn static_id_wrong_way<'a>(t: &'a ()) -> &'static () where 'static: 'a {
     t //[ll]~ ERROR E0312
-        //[nll]~^ ERROR unsatisfied lifetime constraints
+        //[nll]~^ ERROR lifetime may not live long enough
 }
 
 fn error(u: &(), v: &()) {
diff --git a/src/test/ui/repr/repr-align.rs b/src/test/ui/repr/repr-align.rs
index 78ed6c7e1c417..9ce89e82ca225 100644
--- a/src/test/ui/repr/repr-align.rs
+++ b/src/test/ui/repr/repr-align.rs
@@ -1,3 +1,4 @@
+#![feature(repr_align_enum)]
 #![allow(dead_code)]
 
 #[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
@@ -12,4 +13,7 @@ struct C(i32);
 #[repr(align(536870912))] // ok: this is the largest accepted alignment
 struct D(i32);
 
+#[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
+enum E { Left, Right }
+
 fn main() {}
diff --git a/src/test/ui/repr/repr-align.stderr b/src/test/ui/repr/repr-align.stderr
index e8dbf74232bfa..f1a5d88ace1fd 100644
--- a/src/test/ui/repr/repr-align.stderr
+++ b/src/test/ui/repr/repr-align.stderr
@@ -1,21 +1,27 @@
 error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
-  --> $DIR/repr-align.rs:3:8
+  --> $DIR/repr-align.rs:4:8
    |
 LL | #[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
    |        ^^^^^^^^^^^
 
 error[E0589]: invalid `repr(align)` attribute: not a power of two
-  --> $DIR/repr-align.rs:6:8
+  --> $DIR/repr-align.rs:7:8
    |
 LL | #[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
    |        ^^^^^^^^^
 
 error[E0589]: invalid `repr(align)` attribute: larger than 2^29
-  --> $DIR/repr-align.rs:9:8
+  --> $DIR/repr-align.rs:10:8
    |
 LL | #[repr(align(4294967296))] //~ ERROR: invalid `repr(align)` attribute: larger than 2^29
    |        ^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error[E0589]: invalid `repr(align)` attribute: not a power of two
+  --> $DIR/repr-align.rs:16:8
+   |
+LL | #[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
+   |        ^^^^^^^^^
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0589`.
diff --git a/src/test/ui/resolve/privacy-struct-ctor.stderr b/src/test/ui/resolve/privacy-struct-ctor.stderr
index 44ecf6b97bf50..519e74d9f6315 100644
--- a/src/test/ui/resolve/privacy-struct-ctor.stderr
+++ b/src/test/ui/resolve/privacy-struct-ctor.stderr
@@ -2,25 +2,16 @@ error[E0423]: expected value, found struct `Z`
   --> $DIR/privacy-struct-ctor.rs:20:9
    |
 LL |         Z;
-   |         ^ constructor is not visible here due to private fields
-help: a tuple struct with a similar name exists
-   |
-LL |         S;
    |         ^
-help: possible better candidate is found in another module, you can import it into scope
-   |
-LL |     use m::n::Z;
-   |
+   |         |
+   |         constructor is not visible here due to private fields
+   |         help: a tuple struct with a similar name exists: `S`
 
 error[E0423]: expected value, found struct `S`
   --> $DIR/privacy-struct-ctor.rs:33:5
    |
 LL |     S;
    |     ^ constructor is not visible here due to private fields
-help: possible better candidate is found in another module, you can import it into scope
-   |
-LL | use m::S;
-   |
 
 error[E0423]: expected value, found struct `S2`
   --> $DIR/privacy-struct-ctor.rs:38:5
diff --git a/src/test/ui/resolve/resolve-conflict-import-vs-import.stderr b/src/test/ui/resolve/resolve-conflict-import-vs-import.stderr
index 2852d122e5e4a..1b4b058b783ad 100644
--- a/src/test/ui/resolve/resolve-conflict-import-vs-import.stderr
+++ b/src/test/ui/resolve/resolve-conflict-import-vs-import.stderr
@@ -4,13 +4,12 @@ error[E0252]: the name `transmute` is defined multiple times
 LL | use std::mem::transmute;
    |     ------------------- previous import of the value `transmute` here
 LL | use std::mem::transmute;
-   |     ^^^^^^^^^^^^^^^^^^^ `transmute` reimported here
+   | ----^^^^^^^^^^^^^^^^^^^-
+   | |   |
+   | |   `transmute` reimported here
+   | help: remove unnecessary import
    |
    = note: `transmute` must be defined only once in the value namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use std::mem::transmute as other_transmute;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/resolve/resolve-hint-macro.stderr b/src/test/ui/resolve/resolve-hint-macro.stderr
index 4f6d0f695df44..ebe3c36f21eb1 100644
--- a/src/test/ui/resolve/resolve-hint-macro.stderr
+++ b/src/test/ui/resolve/resolve-hint-macro.stderr
@@ -2,7 +2,7 @@ error[E0423]: expected function, found macro `assert`
   --> $DIR/resolve-hint-macro.rs:2:5
    |
 LL |     assert(true);
-   |     ^^^^^^ did you mean `assert!(...)`?
+   |     ^^^^^^ help: use `!` to invoke the macro: `assert!`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/resolve/resolve-type-param-in-item-in-trait.rs b/src/test/ui/resolve/resolve-type-param-in-item-in-trait.rs
index 112427a3fceae..c77a66524f73f 100644
--- a/src/test/ui/resolve/resolve-type-param-in-item-in-trait.rs
+++ b/src/test/ui/resolve/resolve-type-param-in-item-in-trait.rs
@@ -6,7 +6,7 @@ trait TraitA<A> {
     fn outer(&self) {
         enum Foo<B> {
             Variance(A)
-                //~^ ERROR can't use type parameters from outer function
+                //~^ ERROR can't use generic parameters from outer function
         }
     }
 }
@@ -14,21 +14,21 @@ trait TraitA<A> {
 trait TraitB<A> {
     fn outer(&self) {
         struct Foo<B>(A);
-                //~^ ERROR can't use type parameters from outer function
+                //~^ ERROR can't use generic parameters from outer function
     }
 }
 
 trait TraitC<A> {
     fn outer(&self) {
         struct Foo<B> { a: A }
-                //~^ ERROR can't use type parameters from outer function
+                //~^ ERROR can't use generic parameters from outer function
     }
 }
 
 trait TraitD<A> {
     fn outer(&self) {
         fn foo<B>(a: A) { }
-                //~^ ERROR can't use type parameters from outer function
+                //~^ ERROR can't use generic parameters from outer function
     }
 }
 
diff --git a/src/test/ui/resolve/resolve-type-param-in-item-in-trait.stderr b/src/test/ui/resolve/resolve-type-param-in-item-in-trait.stderr
index 8eca720d88e8c..f6b8abf4057e5 100644
--- a/src/test/ui/resolve/resolve-type-param-in-item-in-trait.stderr
+++ b/src/test/ui/resolve/resolve-type-param-in-item-in-trait.stderr
@@ -1,44 +1,44 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/resolve-type-param-in-item-in-trait.rs:8:22
    |
 LL | trait TraitA<A> {
    |              - type variable from outer function
 LL |     fn outer(&self) {
-   |        ----- try adding a local type parameter in this method instead
+   |        ----- try adding a local generic parameter in this method instead
 LL |         enum Foo<B> {
 LL |             Variance(A)
-   |                      ^ use of type variable from outer function
+   |                      ^ use of generic parameter from outer function
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/resolve-type-param-in-item-in-trait.rs:16:23
    |
 LL | trait TraitB<A> {
    |              - type variable from outer function
 LL |     fn outer(&self) {
-   |        ----- try adding a local type parameter in this method instead
+   |        ----- try adding a local generic parameter in this method instead
 LL |         struct Foo<B>(A);
-   |                       ^ use of type variable from outer function
+   |                       ^ use of generic parameter from outer function
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/resolve-type-param-in-item-in-trait.rs:23:28
    |
 LL | trait TraitC<A> {
    |              - type variable from outer function
 LL |     fn outer(&self) {
-   |        ----- try adding a local type parameter in this method instead
+   |        ----- try adding a local generic parameter in this method instead
 LL |         struct Foo<B> { a: A }
-   |                            ^ use of type variable from outer function
+   |                            ^ use of generic parameter from outer function
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/resolve-type-param-in-item-in-trait.rs:30:22
    |
 LL | trait TraitD<A> {
    |              - type variable from outer function
 LL |     fn outer(&self) {
 LL |         fn foo<B>(a: A) { }
-   |            ------    ^ use of type variable from outer function
+   |            ------    ^ use of generic parameter from outer function
    |            |
-   |            help: try using a local type parameter instead: `foo<B, A>`
+   |            help: try using a local generic parameter instead: `foo<B, A>`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr b/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
index 8a9426bfee862..b7b158ce7efa6 100644
--- a/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
+++ b/src/test/ui/resolve/suggest-path-instead-of-mod-dot-item.stderr
@@ -4,15 +4,15 @@ error[E0423]: expected value, found module `a`
 LL |     a.I
    |     ^--
    |     |
-   |     did you mean `a::I`?
+   |     help: use the path separator to refer to an item: `a::I`
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:22:5
    |
 LL |     a.g()
-   |     ^----
+   |     ^--
    |     |
-   |     did you mean `a::g(...)`?
+   |     help: use the path separator to refer to an item: `a::g`
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:27:5
@@ -20,16 +20,21 @@ error[E0423]: expected value, found module `a`
 LL |     a.b.J
    |     ^--
    |     |
-   |     did you mean `a::b`?
+   |     help: use the path separator to refer to an item: `a::b`
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:32:5
    |
 LL |     a::b.J
-   |     ^^^---
-   |     |  |
-   |     |  help: a constant with a similar name exists: `I`
-   |     did you mean `a::b::J`?
+   |     ^^^^
+help: a constant with a similar name exists
+   |
+LL |     a::I.J
+   |        ^
+help: use the path separator to refer to an item
+   |
+LL |     a::b::J
+   |
 
 error[E0423]: expected value, found module `a`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:37:5
@@ -37,7 +42,7 @@ error[E0423]: expected value, found module `a`
 LL |     a.b.f();
    |     ^--
    |     |
-   |     did you mean `a::b`?
+   |     help: use the path separator to refer to an item: `a::b`
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:40:12
@@ -51,10 +56,15 @@ error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:45:5
    |
 LL |     a::b.f()
-   |     ^^^-----
-   |     |  |
-   |     |  help: a constant with a similar name exists: `I`
-   |     did you mean `a::b::f(...)`?
+   |     ^^^^
+help: a constant with a similar name exists
+   |
+LL |     a::I.f()
+   |        ^
+help: use the path separator to refer to an item
+   |
+LL |     a::b::f()
+   |     ^^^^^^^
 
 error[E0423]: expected value, found module `a::b`
   --> $DIR/suggest-path-instead-of-mod-dot-item.rs:50:5
diff --git a/src/test/ui/resolve/token-error-correct-3.rs b/src/test/ui/resolve/token-error-correct-3.rs
index 86cf71117a6f8..b1ca0bbfc57c1 100644
--- a/src/test/ui/resolve/token-error-correct-3.rs
+++ b/src/test/ui/resolve/token-error-correct-3.rs
@@ -17,7 +17,7 @@ pub mod raw {
             //~| expected type `()`
             //~| found type `std::result::Result<bool, std::io::Error>`
             //~| expected one of
-        } else { //~ ERROR: incorrect close delimiter: `}`
+        } else {
             //~^ ERROR: expected one of
             //~| unexpected token
             Ok(false);
diff --git a/src/test/ui/resolve/token-error-correct-3.stderr b/src/test/ui/resolve/token-error-correct-3.stderr
index 2164d27a05174..a6bb83c71f313 100644
--- a/src/test/ui/resolve/token-error-correct-3.stderr
+++ b/src/test/ui/resolve/token-error-correct-3.stderr
@@ -1,19 +1,11 @@
-error: incorrect close delimiter: `}`
-  --> $DIR/token-error-correct-3.rs:20:9
-   |
-LL |         if !is_directory(path.as_ref()) { //~ ERROR: cannot find function `is_directory`
-   |                                         - close delimiter possibly meant for this
-LL |             callback(path.as_ref(); //~ ERROR expected one of
-   |                     - un-closed delimiter
-...
-LL |         } else { //~ ERROR: incorrect close delimiter: `}`
-   |         ^ incorrect close delimiter
-
 error: expected one of `)`, `,`, `.`, `?`, or an operator, found `;`
   --> $DIR/token-error-correct-3.rs:14:35
    |
 LL |             callback(path.as_ref(); //~ ERROR expected one of
-   |                                   ^ expected one of `)`, `,`, `.`, `?`, or an operator here
+   |                     -             ^
+   |                     |             |
+   |                     |             help: `)` may belong here
+   |                     unclosed delimiter
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
   --> $DIR/token-error-correct-3.rs:20:9
@@ -21,7 +13,7 @@ error: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
 LL |             fs::create_dir_all(path.as_ref()).map(|()| true) //~ ERROR: mismatched types
    |                                                             - expected one of `.`, `;`, `?`, `}`, or an operator here
 ...
-LL |         } else { //~ ERROR: incorrect close delimiter: `}`
+LL |         } else {
    |         ^ unexpected token
 
 error[E0425]: cannot find function `is_directory` in this scope
@@ -41,7 +33,7 @@ LL |             fs::create_dir_all(path.as_ref()).map(|()| true) //~ ERROR: mis
    = note: expected type `()`
               found type `std::result::Result<bool, std::io::Error>`
 
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
 Some errors occurred: E0308, E0425.
 For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/resolve/token-error-correct.rs b/src/test/ui/resolve/token-error-correct.rs
index b97e22f7d910b..d64907780efb5 100644
--- a/src/test/ui/resolve/token-error-correct.rs
+++ b/src/test/ui/resolve/token-error-correct.rs
@@ -2,6 +2,8 @@
 
 fn main() {
     foo(bar(;
-    //~^ ERROR: expected expression, found `;`
+    //~^ ERROR cannot find function `bar` in this scope
 }
 //~^ ERROR: incorrect close delimiter: `}`
+
+fn foo(_: usize) {}
diff --git a/src/test/ui/resolve/token-error-correct.stderr b/src/test/ui/resolve/token-error-correct.stderr
index 0a4590461b5ab..b0827ea7367c2 100644
--- a/src/test/ui/resolve/token-error-correct.stderr
+++ b/src/test/ui/resolve/token-error-correct.stderr
@@ -5,15 +5,16 @@ LL | fn main() {
    |           - close delimiter possibly meant for this
 LL |     foo(bar(;
    |            - un-closed delimiter
-LL |     //~^ ERROR: expected expression, found `;`
+LL |     //~^ ERROR cannot find function `bar` in this scope
 LL | }
    | ^ incorrect close delimiter
 
-error: expected expression, found `;`
-  --> $DIR/token-error-correct.rs:4:13
+error[E0425]: cannot find function `bar` in this scope
+  --> $DIR/token-error-correct.rs:4:9
    |
 LL |     foo(bar(;
-   |             ^ expected expression
+   |         ^^^ not found in this scope
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/return/return-from-diverging.stderr b/src/test/ui/return/return-from-diverging.stderr
index c84dd1953a07b..2862ae641df15 100644
--- a/src/test/ui/return/return-from-diverging.stderr
+++ b/src/test/ui/return/return-from-diverging.stderr
@@ -1,6 +1,8 @@
 error[E0308]: mismatched types
   --> $DIR/return-from-diverging.rs:4:12
    |
+LL | fn fail() -> ! {
+   |              - expected `!` because of return type
 LL |     return "wow"; //~ ERROR mismatched types
    |            ^^^^^ expected !, found reference
    |
diff --git a/src/test/ui/rfc-2005-default-binding-mode/borrowck-issue-49631.nll.stderr b/src/test/ui/rfc-2005-default-binding-mode/borrowck-issue-49631.nll.stderr
index 9e242712b9e84..3a6f66ca4dac5 100644
--- a/src/test/ui/rfc-2005-default-binding-mode/borrowck-issue-49631.nll.stderr
+++ b/src/test/ui/rfc-2005-default-binding-mode/borrowck-issue-49631.nll.stderr
@@ -7,7 +7,7 @@ LL |         foo.mutate();
    |         ^^^^^^^^^^^^ mutable borrow occurs here
 LL |         //~^ ERROR cannot borrow `foo` as mutable
 LL |         println!("foo={:?}", *string);
-   |                              ------- immutable borrow used here, in later iteration of loop
+   |                              ------- immutable borrow later used here
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.nll.stderr b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.nll.stderr
index 0b3f59fd7e452..5a730ad2be42c 100644
--- a/src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.nll.stderr
+++ b/src/test/ui/rfc-2361-dbg-macro/dbg-macro-move-semantics.nll.stderr
@@ -1,12 +1,13 @@
 error[E0382]: use of moved value: `a`
   --> $DIR/dbg-macro-move-semantics.rs:9:18
    |
+LL |     let a = NoCopy(0);
+   |         - move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
 LL |     let _ = dbg!(a);
    |             ------- value moved here
 LL |     let _ = dbg!(a); //~ ERROR use of moved value
    |                  ^ value used here after move
    |
-   = note: move occurs because `a` has type `NoCopy`, which does not implement the `Copy` trait
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)
 
 error: aborting due to previous error
diff --git a/src/test/ui/rfc1598-generic-associated-types/empty_generics.rs b/src/test/ui/rfc1598-generic-associated-types/empty_generics.rs
index 158ebc7d3888a..afc27701920dc 100644
--- a/src/test/ui/rfc1598-generic-associated-types/empty_generics.rs
+++ b/src/test/ui/rfc1598-generic-associated-types/empty_generics.rs
@@ -3,7 +3,7 @@
 
 trait Foo {
     type Bar<,>;
-    //~^ ERROR expected one of `>`, identifier, or lifetime, found `,`
+    //~^ ERROR expected one of `>`, `const`, identifier, or lifetime, found `,`
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc1598-generic-associated-types/empty_generics.stderr b/src/test/ui/rfc1598-generic-associated-types/empty_generics.stderr
index 2a01b2a3f0fa5..5b98302924e3c 100644
--- a/src/test/ui/rfc1598-generic-associated-types/empty_generics.stderr
+++ b/src/test/ui/rfc1598-generic-associated-types/empty_generics.stderr
@@ -1,8 +1,8 @@
-error: expected one of `>`, identifier, or lifetime, found `,`
+error: expected one of `>`, `const`, identifier, or lifetime, found `,`
   --> $DIR/empty_generics.rs:5:14
    |
 LL |     type Bar<,>;
-   |              ^ expected one of `>`, identifier, or lifetime here
+   |              ^ expected one of `>`, `const`, identifier, or lifetime here
 
 warning: the feature `generic_associated_types` is incomplete and may cause the compiler to crash
   --> $DIR/empty_generics.rs:1:12
diff --git a/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.rs b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.rs
new file mode 100644
index 0000000000000..931ee9db1fe15
--- /dev/null
+++ b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.rs
@@ -0,0 +1,90 @@
+// Test that the simd_bitmask intrinsic produces ok-ish error
+// messages when misused.
+
+#![feature(repr_simd, platform_intrinsics)]
+#![allow(non_camel_case_types)]
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct u32x2(pub u32, pub u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+pub struct u32x4(pub u32, pub u32, pub u32, pub u32);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+struct u8x8(
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+struct u8x16(
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+struct u8x32(
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+);
+
+#[repr(simd)]
+#[derive(Copy, Clone)]
+struct u8x64(
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+    pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8, pub u8,
+);
+
+extern "platform-intrinsic" {
+    fn simd_bitmask<T, U>(x: T) -> U;
+}
+
+fn main() {
+    let m2 = u32x2(0, 0);
+    let m4 = u32x4(0, 0, 0, 0);
+    let m8 = u8x8(0, 0, 0, 0, 0, 0, 0, 0);
+    let m16 = u8x16(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+    let m32 = u8x32(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+    let m64 = u8x64(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+
+    unsafe {
+        let _: u8 = simd_bitmask(m2);
+        let _: u8 = simd_bitmask(m4);
+        let _: u8 = simd_bitmask(m8);
+        let _: u16 = simd_bitmask(m16);
+        let _: u32 = simd_bitmask(m32);
+        let _: u64 = simd_bitmask(m64);
+
+        let _: u16 = simd_bitmask(m2);
+        //~^ ERROR bitmask `u16`, expected `u8`
+
+        let _: u16 = simd_bitmask(m8);
+        //~^ ERROR bitmask `u16`, expected `u8`
+
+        let _: u32 = simd_bitmask(m16);
+        //~^ ERROR bitmask `u32`, expected `u16`
+
+        let _: u64 = simd_bitmask(m32);
+        //~^ ERROR bitmask `u64`, expected `u32`
+
+        let _: u128 = simd_bitmask(m64);
+        //~^ ERROR bitmask `u128`, expected `u64`
+
+   }
+}
diff --git a/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.stderr b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.stderr
new file mode 100644
index 0000000000000..d016838d098d4
--- /dev/null
+++ b/src/test/ui/simd-intrinsic/simd-intrinsic-generic-bitmask.stderr
@@ -0,0 +1,33 @@
+error[E0511]: invalid monomorphization of `simd_bitmask` intrinsic: bitmask `u16`, expected `u8`
+  --> $DIR/simd-intrinsic-generic-bitmask.rs:74:22
+   |
+LL |         let _: u16 = simd_bitmask(m2);
+   |                      ^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_bitmask` intrinsic: bitmask `u16`, expected `u8`
+  --> $DIR/simd-intrinsic-generic-bitmask.rs:77:22
+   |
+LL |         let _: u16 = simd_bitmask(m8);
+   |                      ^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_bitmask` intrinsic: bitmask `u32`, expected `u16`
+  --> $DIR/simd-intrinsic-generic-bitmask.rs:80:22
+   |
+LL |         let _: u32 = simd_bitmask(m16);
+   |                      ^^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_bitmask` intrinsic: bitmask `u64`, expected `u32`
+  --> $DIR/simd-intrinsic-generic-bitmask.rs:83:22
+   |
+LL |         let _: u64 = simd_bitmask(m32);
+   |                      ^^^^^^^^^^^^^^^^^
+
+error[E0511]: invalid monomorphization of `simd_bitmask` intrinsic: bitmask `u128`, expected `u64`
+  --> $DIR/simd-intrinsic-generic-bitmask.rs:86:23
+   |
+LL |         let _: u128 = simd_bitmask(m64);
+   |                       ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0511`.
diff --git a/src/test/ui/span/issue-24690.stderr b/src/test/ui/span/issue-24690.stderr
index f052f866c901b..964e323b83ed4 100644
--- a/src/test/ui/span/issue-24690.stderr
+++ b/src/test/ui/span/issue-24690.stderr
@@ -2,7 +2,7 @@ warning: unused variable: `theOtherTwo`
   --> $DIR/issue-24690.rs:13:9
    |
 LL |     let theOtherTwo = 2; //~ WARN should have a snake case name
-   |         ^^^^^^^^^^^ help: consider using `_theOtherTwo` instead
+   |         ^^^^^^^^^^^ help: consider prefixing with an underscore: `_theOtherTwo`
    |
 note: lint level defined here
   --> $DIR/issue-24690.rs:8:9
diff --git a/src/test/ui/span/macro-ty-params.stderr b/src/test/ui/span/macro-ty-params.stderr
index 23fdde06e8f9d..965ca7000be80 100644
--- a/src/test/ui/span/macro-ty-params.stderr
+++ b/src/test/ui/span/macro-ty-params.stderr
@@ -1,14 +1,14 @@
 error: generic arguments in macro path
-  --> $DIR/macro-ty-params.rs:10:8
+  --> $DIR/macro-ty-params.rs:10:10
    |
 LL |     foo::<T>!(); //~ ERROR generic arguments in macro path
-   |        ^^^^^
+   |          ^^^
 
 error: generic arguments in macro path
-  --> $DIR/macro-ty-params.rs:11:8
+  --> $DIR/macro-ty-params.rs:11:10
    |
 LL |     foo::<>!(); //~ ERROR generic arguments in macro path
-   |        ^^^^
+   |          ^^
 
 error: unexpected generic arguments in path
   --> $DIR/macro-ty-params.rs:12:8
diff --git a/src/test/ui/span/regions-escape-loop-via-variable.nll.stderr b/src/test/ui/span/regions-escape-loop-via-variable.nll.stderr
index 841e3c484144d..42df668529749 100644
--- a/src/test/ui/span/regions-escape-loop-via-variable.nll.stderr
+++ b/src/test/ui/span/regions-escape-loop-via-variable.nll.stderr
@@ -2,7 +2,7 @@ error[E0597]: `x` does not live long enough
   --> $DIR/regions-escape-loop-via-variable.rs:11:13
    |
 LL |         let x = 1 + *p;
-   |                     -- borrow used here, in later iteration of loop
+   |                     -- borrow later used here
 LL |         p = &x;
    |             ^^ borrowed value does not live long enough
 LL |     }
diff --git a/src/test/ui/span/regions-escape-loop-via-vec.nll.stderr b/src/test/ui/span/regions-escape-loop-via-vec.nll.stderr
index ea64828fedde6..e07fb72778210 100644
--- a/src/test/ui/span/regions-escape-loop-via-vec.nll.stderr
+++ b/src/test/ui/span/regions-escape-loop-via-vec.nll.stderr
@@ -7,7 +7,7 @@ LL |     while x < 10 { //~ ERROR cannot use `x` because it was mutably borrowed
    |           ^ use of borrowed `x`
 LL |         let mut z = x; //~ ERROR cannot use `x` because it was mutably borrowed
 LL |         _y.push(&mut z);
-   |         -- borrow used here, in later iteration of loop
+   |         -- borrow later used here
 
 error[E0503]: cannot use `x` because it was mutably borrowed
   --> $DIR/regions-escape-loop-via-vec.rs:6:21
@@ -18,7 +18,7 @@ LL |     while x < 10 { //~ ERROR cannot use `x` because it was mutably borrowed
 LL |         let mut z = x; //~ ERROR cannot use `x` because it was mutably borrowed
    |                     ^ use of borrowed `x`
 LL |         _y.push(&mut z);
-   |         -- borrow used here, in later iteration of loop
+   |         -- borrow later used here
 
 error[E0597]: `z` does not live long enough
   --> $DIR/regions-escape-loop-via-vec.rs:7:17
@@ -26,7 +26,7 @@ error[E0597]: `z` does not live long enough
 LL |         _y.push(&mut z);
    |         --      ^^^^^^ borrowed value does not live long enough
    |         |
-   |         borrow used here, in later iteration of loop
+   |         borrow later used here
 ...
 LL |     }
    |     - `z` dropped here while still borrowed
@@ -38,7 +38,7 @@ LL |     let mut _y = vec![&mut x];
    |                       ------ borrow of `x` occurs here
 ...
 LL |         _y.push(&mut z);
-   |         -- borrow used here, in later iteration of loop
+   |         -- borrow later used here
 LL |         //~^ ERROR `z` does not live long enough
 LL |         x += 1; //~ ERROR cannot assign
    |         ^^^^^^ use of borrowed `x`
diff --git a/src/test/ui/specialization/issue-39448.rs b/src/test/ui/specialization/issue-39448.rs
new file mode 100644
index 0000000000000..8ac6d8e9311fc
--- /dev/null
+++ b/src/test/ui/specialization/issue-39448.rs
@@ -0,0 +1,50 @@
+#![feature(specialization)]
+
+// Regression test for a specialization-related ICE (#39448).
+
+trait A: Sized {
+    fn foo(self, _: Self) -> Self {
+        self
+    }
+}
+
+impl A for u8 {}
+impl A for u16 {}
+
+impl FromA<u8> for u16 {
+    fn from(x: u8) -> u16 {
+        x as u16
+    }
+}
+
+trait FromA<T> {
+    fn from(T) -> Self;
+}
+
+impl<T: A, U: A + FromA<T>> FromA<T> for U {
+    default fn from(x: T) -> Self {
+        ToA::to(x)
+    }
+}
+
+trait ToA<T> {
+    fn to(self) -> T;
+}
+
+impl<T, U> ToA<U> for T
+where
+    U: FromA<T>,
+{
+    fn to(self) -> U {
+        U::from(self)
+    }
+}
+
+#[allow(dead_code)]
+fn foo<T: A, U: A>(x: T, y: U) -> U {
+    x.foo(y.to()).to() //~ ERROR overflow evaluating the requirement
+}
+
+fn main() {
+    let z = foo(8u8, 1u16);
+}
diff --git a/src/test/ui/specialization/issue-39448.stderr b/src/test/ui/specialization/issue-39448.stderr
new file mode 100644
index 0000000000000..0b0fd2c4af591
--- /dev/null
+++ b/src/test/ui/specialization/issue-39448.stderr
@@ -0,0 +1,12 @@
+error[E0275]: overflow evaluating the requirement `T: FromA<U>`
+  --> $DIR/issue-39448.rs:45:13
+   |
+LL |     x.foo(y.to()).to() //~ ERROR overflow evaluating the requirement
+   |             ^^
+   |
+   = note: required because of the requirements on the impl of `FromA<U>` for `T`
+   = note: required because of the requirements on the impl of `ToA<T>` for `U`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0275`.
diff --git a/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.rs b/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.rs
new file mode 100644
index 0000000000000..8f750ae62f5e4
--- /dev/null
+++ b/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.rs
@@ -0,0 +1,4 @@
+#![feature(staged_api)]
+//~^ ERROR crate has missing stability attribute
+
+fn main() {}
diff --git a/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.stderr b/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.stderr
new file mode 100644
index 0000000000000..f674797694557
--- /dev/null
+++ b/src/test/ui/stability-attribute/missing-stability-attr-at-top-level.stderr
@@ -0,0 +1,11 @@
+error: crate has missing stability attribute
+  --> $DIR/missing-stability-attr-at-top-level.rs:1:1
+   |
+LL | / #![feature(staged_api)]
+LL | | //~^ ERROR crate has missing stability attribute
+LL | |
+LL | | fn main() {}
+   | |____________^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/stability-attribute/stability-attribute-issue-43027.rs b/src/test/ui/stability-attribute/stability-attribute-issue-43027.rs
index 596a6eb6ed366..0b243bb52119b 100644
--- a/src/test/ui/stability-attribute/stability-attribute-issue-43027.rs
+++ b/src/test/ui/stability-attribute/stability-attribute-issue-43027.rs
@@ -2,7 +2,7 @@
 #![stable(feature = "test", since = "0")]
 
 #[stable(feature = "test", since = "0")]
-pub struct Reverse<T>(pub T); //~ ERROR This node does not have a stability attribute
+pub struct Reverse<T>(pub T); //~ ERROR field has missing stability attribute
 
 fn main() {
     // Make sure the field is used to fill the stability cache
diff --git a/src/test/ui/stability-attribute/stability-attribute-issue-43027.stderr b/src/test/ui/stability-attribute/stability-attribute-issue-43027.stderr
index e123f42023324..7ffb4bb487a7b 100644
--- a/src/test/ui/stability-attribute/stability-attribute-issue-43027.stderr
+++ b/src/test/ui/stability-attribute/stability-attribute-issue-43027.stderr
@@ -1,7 +1,7 @@
-error: This node does not have a stability attribute
+error: field has missing stability attribute
   --> $DIR/stability-attribute-issue-43027.rs:5:23
    |
-LL | pub struct Reverse<T>(pub T); //~ ERROR This node does not have a stability attribute
+LL | pub struct Reverse<T>(pub T); //~ ERROR field has missing stability attribute
    |                       ^^^^^
 
 error: aborting due to previous error
diff --git a/src/test/ui/stability-attribute/stability-attribute-sanity-3.rs b/src/test/ui/stability-attribute/stability-attribute-sanity-3.rs
index 0c132e8857550..13ef3d3f53d2b 100644
--- a/src/test/ui/stability-attribute/stability-attribute-sanity-3.rs
+++ b/src/test/ui/stability-attribute/stability-attribute-sanity-3.rs
@@ -5,7 +5,7 @@
 #![stable(feature = "stable_test_feature", since = "1.0.0")]
 
 #[macro_export]
-macro_rules! mac { //~ ERROR This node does not have a stability attribute
+macro_rules! mac { //~ ERROR macro has missing stability attribute
     () => ()
 }
 
diff --git a/src/test/ui/stability-attribute/stability-attribute-sanity-3.stderr b/src/test/ui/stability-attribute/stability-attribute-sanity-3.stderr
index d42dcc0c778a7..1c759d49b9947 100644
--- a/src/test/ui/stability-attribute/stability-attribute-sanity-3.stderr
+++ b/src/test/ui/stability-attribute/stability-attribute-sanity-3.stderr
@@ -1,7 +1,7 @@
-error: This node does not have a stability attribute
+error: macro has missing stability attribute
   --> $DIR/stability-attribute-sanity-3.rs:8:1
    |
-LL | / macro_rules! mac { //~ ERROR This node does not have a stability attribute
+LL | / macro_rules! mac { //~ ERROR macro has missing stability attribute
 LL | |     () => ()
 LL | | }
    | |_^
diff --git a/src/test/ui/stability-in-private-module.rs b/src/test/ui/stability-in-private-module.rs
new file mode 100644
index 0000000000000..f12e9198b0d7c
--- /dev/null
+++ b/src/test/ui/stability-in-private-module.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let _ = std::thread::thread_info::current_thread();
+    //~^ERROR module `thread_info` is private
+}
diff --git a/src/test/ui/stability-in-private-module.stderr b/src/test/ui/stability-in-private-module.stderr
new file mode 100644
index 0000000000000..c3edd62a15eda
--- /dev/null
+++ b/src/test/ui/stability-in-private-module.stderr
@@ -0,0 +1,9 @@
+error[E0603]: module `thread_info` is private
+  --> $DIR/stability-in-private-module.rs:2:26
+   |
+LL |     let _ = std::thread::thread_info::current_thread();
+   |                          ^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0603`.
diff --git a/src/test/ui/static/static-drop-scope.nll.stderr b/src/test/ui/static/static-drop-scope.nll.stderr
index 3c01f694bff47..df6383b4fc222 100644
--- a/src/test/ui/static/static-drop-scope.nll.stderr
+++ b/src/test/ui/static/static-drop-scope.nll.stderr
@@ -54,7 +54,19 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     (x, ()).1
    |     ^^^^^^^ constant functions cannot evaluate destructors
 
-error: aborting due to 8 previous errors
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/static-drop-scope.rs:31:34
+   |
+LL | const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
+   |                                  ^^^^^^^^^^^^^^^^^^^ constants cannot evaluate destructors
+
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/static-drop-scope.rs:36:43
+   |
+LL | const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
+   |                                           ^^^^^^^^^^^ constants cannot evaluate destructors
+
+error: aborting due to 10 previous errors
 
 Some errors occurred: E0493, E0716.
 For more information about an error, try `rustc --explain E0493`.
diff --git a/src/test/ui/static/static-drop-scope.rs b/src/test/ui/static/static-drop-scope.rs
index a11a9f020e0dc..e5a9f2a405644 100644
--- a/src/test/ui/static/static-drop-scope.rs
+++ b/src/test/ui/static/static-drop-scope.rs
@@ -28,4 +28,12 @@ const fn const_drop2<T>(x: T) {
     //~^ ERROR destructors cannot be evaluated at compile-time
 }
 
+const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
+//~^ ERROR destructors cannot be evaluated at compile-time
+
+const HELPER: Option<WithDtor> = Some(WithDtor);
+
+const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
+//~^ ERROR destructors cannot be evaluated at compile-time
+
 fn main () {}
diff --git a/src/test/ui/static/static-drop-scope.stderr b/src/test/ui/static/static-drop-scope.stderr
index 89b31d95a2a4e..3e3032eb4fb60 100644
--- a/src/test/ui/static/static-drop-scope.stderr
+++ b/src/test/ui/static/static-drop-scope.stderr
@@ -54,7 +54,19 @@ error[E0493]: destructors cannot be evaluated at compile-time
 LL |     (x, ()).1
    |     ^^^^^^^ constant functions cannot evaluate destructors
 
-error: aborting due to 8 previous errors
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/static-drop-scope.rs:31:34
+   |
+LL | const EARLY_DROP_C_OPTION: i32 = (Some(WithDtor), 0).1;
+   |                                  ^^^^^^^^^^^^^^^^^^^ constants cannot evaluate destructors
+
+error[E0493]: destructors cannot be evaluated at compile-time
+  --> $DIR/static-drop-scope.rs:36:43
+   |
+LL | const EARLY_DROP_C_OPTION_CONSTANT: i32 = (HELPER, 0).1;
+   |                                           ^^^^^^^^^^^ constants cannot evaluate destructors
+
+error: aborting due to 10 previous errors
 
 Some errors occurred: E0493, E0597.
 For more information about an error, try `rustc --explain E0493`.
diff --git a/src/test/ui/str/str-as-char.fixed b/src/test/ui/str/str-as-char.fixed
index 9d4297b55c816..accead5c850cc 100644
--- a/src/test/ui/str/str-as-char.fixed
+++ b/src/test/ui/str/str-as-char.fixed
@@ -1,6 +1,6 @@
 // run-rustfix
 
 fn main() {
-    println!("●●");
-    //~^ ERROR character literal may only contain one codepoint
+    println!("{}", "●●"); //~ ERROR character literal may only contain one codepoint
+    //~^ ERROR format argument must be a string literal
 }
diff --git a/src/test/ui/str/str-as-char.rs b/src/test/ui/str/str-as-char.rs
index 710fa74a32a1c..fb179ec7245d2 100644
--- a/src/test/ui/str/str-as-char.rs
+++ b/src/test/ui/str/str-as-char.rs
@@ -1,6 +1,6 @@
 // run-rustfix
 
 fn main() {
-    println!('●●');
-    //~^ ERROR character literal may only contain one codepoint
+    println!('●●'); //~ ERROR character literal may only contain one codepoint
+    //~^ ERROR format argument must be a string literal
 }
diff --git a/src/test/ui/str/str-as-char.stderr b/src/test/ui/str/str-as-char.stderr
index 540a1b55376ff..4ca430a4cde9b 100644
--- a/src/test/ui/str/str-as-char.stderr
+++ b/src/test/ui/str/str-as-char.stderr
@@ -1,12 +1,22 @@
 error: character literal may only contain one codepoint
   --> $DIR/str-as-char.rs:4:14
    |
-LL |     println!('●●');
+LL |     println!('●●'); //~ ERROR character literal may only contain one codepoint
    |              ^^^^
 help: if you meant to write a `str` literal, use double quotes
    |
-LL |     println!("●●");
+LL |     println!("●●"); //~ ERROR character literal may only contain one codepoint
    |              ^^^^
 
-error: aborting due to previous error
+error: format argument must be a string literal
+  --> $DIR/str-as-char.rs:4:14
+   |
+LL |     println!('●●'); //~ ERROR character literal may only contain one codepoint
+   |              ^^^^
+help: you might be missing a string literal to format with
+   |
+LL |     println!("{}", '●●'); //~ ERROR character literal may only contain one codepoint
+   |              ^^^^^
+
+error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/str/str-idx.rs b/src/test/ui/str/str-idx.rs
index 2ea80494e03cb..1b32ed5533d35 100644
--- a/src/test/ui/str/str-idx.rs
+++ b/src/test/ui/str/str-idx.rs
@@ -1,4 +1,7 @@
 pub fn main() {
     let s: &str = "hello";
-    let c: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _ = s.get(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _ = s.get_unchecked(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+    let _: u8 = s['c']; //~ ERROR the type `str` cannot be indexed by `char`
 }
diff --git a/src/test/ui/str/str-idx.stderr b/src/test/ui/str/str-idx.stderr
index 108096df9c41c..99df85d92fd96 100644
--- a/src/test/ui/str/str-idx.stderr
+++ b/src/test/ui/str/str-idx.stderr
@@ -1,11 +1,43 @@
 error[E0277]: the type `str` cannot be indexed by `{integer}`
   --> $DIR/str-idx.rs:3:17
    |
-LL |     let c: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
-   |                 ^^^^ `str` cannot be indexed by `{integer}`
+LL |     let _: u8 = s[4]; //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |                 ^^^^ string indices are ranges of `usize`
    |
-   = help: the trait `std::ops::Index<{integer}>` is not implemented for `str`
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+   = note: required because of the requirements on the impl of `std::ops::Index<{integer}>` for `str`
 
-error: aborting due to previous error
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-idx.rs:4:15
+   |
+LL |     let _ = s.get(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |               ^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-idx.rs:5:15
+   |
+LL |     let _ = s.get_unchecked(4); //~ ERROR the type `str` cannot be indexed by `{integer}`
+   |               ^^^^^^^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `char`
+  --> $DIR/str-idx.rs:6:17
+   |
+LL |     let _: u8 = s['c']; //~ ERROR the type `str` cannot be indexed by `char`
+   |                 ^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `char`
+   = note: required because of the requirements on the impl of `std::ops::Index<char>` for `str`
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/str/str-mut-idx.rs b/src/test/ui/str/str-mut-idx.rs
index cebbbc3ccbf7d..575a9eae85946 100644
--- a/src/test/ui/str/str-mut-idx.rs
+++ b/src/test/ui/str/str-mut-idx.rs
@@ -5,7 +5,13 @@ fn mutate(s: &mut str) {
     //~^ ERROR the size for values of type
     //~| ERROR the size for values of type
     s[1usize] = bot();
-    //~^ ERROR the type `str` cannot be mutably indexed by `usize`
+    //~^ ERROR the type `str` cannot be indexed by `usize`
+    s.get_mut(1);
+    //~^ ERROR the type `str` cannot be indexed by `{integer}`
+    s.get_unchecked_mut(1);
+    //~^ ERROR the type `str` cannot be indexed by `{integer}`
+    s['c'];
+    //~^ ERROR the type `str` cannot be indexed by `char`
 }
 
 pub fn main() {}
diff --git a/src/test/ui/str/str-mut-idx.stderr b/src/test/ui/str/str-mut-idx.stderr
index a0c7c2c574e4e..beb2272452363 100644
--- a/src/test/ui/str/str-mut-idx.stderr
+++ b/src/test/ui/str/str-mut-idx.stderr
@@ -22,14 +22,44 @@ LL |     s[1..2] = bot();
    = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
    = note: the left-hand-side of an assignment must have a statically known size
 
-error[E0277]: the type `str` cannot be mutably indexed by `usize`
+error[E0277]: the type `str` cannot be indexed by `usize`
   --> $DIR/str-mut-idx.rs:7:5
    |
 LL |     s[1usize] = bot();
-   |     ^^^^^^^^^ `str` cannot be mutably indexed by `usize`
+   |     ^^^^^^^^^ string indices are ranges of `usize`
    |
-   = help: the trait `std::ops::IndexMut<usize>` is not implemented for `str`
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `usize`
+   = note: required because of the requirements on the impl of `std::ops::Index<usize>` for `str`
 
-error: aborting due to 3 previous errors
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-mut-idx.rs:9:7
+   |
+LL |     s.get_mut(1);
+   |       ^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `{integer}`
+  --> $DIR/str-mut-idx.rs:11:7
+   |
+LL |     s.get_unchecked_mut(1);
+   |       ^^^^^^^^^^^^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `{integer}`
+   = note: you can use `.chars().nth()` or `.bytes().nth()`
+           see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#indexing-into-strings>
+
+error[E0277]: the type `str` cannot be indexed by `char`
+  --> $DIR/str-mut-idx.rs:13:5
+   |
+LL |     s['c'];
+   |     ^^^^^^ string indices are ranges of `usize`
+   |
+   = help: the trait `std::slice::SliceIndex<str>` is not implemented for `char`
+   = note: required because of the requirements on the impl of `std::ops::Index<char>` for `str`
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/suggestions/as-ref.stderr b/src/test/ui/suggestions/as-ref.stderr
index 7273496a7ce06..8143acc957b4c 100644
--- a/src/test/ui/suggestions/as-ref.stderr
+++ b/src/test/ui/suggestions/as-ref.stderr
@@ -2,9 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/as-ref.rs:6:27
    |
 LL |   opt.map(|arg| takes_ref(arg));
-   |       -                   ^^^ expected &Foo, found struct `Foo`
+   |       ---                 ^^^ expected &Foo, found struct `Foo`
    |       |
-   |       help: consider using `as_ref` instead: `as_ref().`
+   |       help: consider using `as_ref` instead: `as_ref().map`
    |
    = note: expected type `&Foo`
               found type `Foo`
@@ -13,9 +13,9 @@ error[E0308]: mismatched types
   --> $DIR/as-ref.rs:8:37
    |
 LL |   opt.and_then(|arg| Some(takes_ref(arg)));
-   |       -                             ^^^ expected &Foo, found struct `Foo`
+   |       --------                      ^^^ expected &Foo, found struct `Foo`
    |       |
-   |       help: consider using `as_ref` instead: `as_ref().`
+   |       help: consider using `as_ref` instead: `as_ref().and_then`
    |
    = note: expected type `&Foo`
               found type `Foo`
@@ -24,9 +24,9 @@ error[E0308]: mismatched types
   --> $DIR/as-ref.rs:11:27
    |
 LL |   opt.map(|arg| takes_ref(arg));
-   |       -                   ^^^ expected &Foo, found struct `Foo`
+   |       ---                 ^^^ expected &Foo, found struct `Foo`
    |       |
-   |       help: consider using `as_ref` instead: `as_ref().`
+   |       help: consider using `as_ref` instead: `as_ref().map`
    |
    = note: expected type `&Foo`
               found type `Foo`
@@ -35,9 +35,9 @@ error[E0308]: mismatched types
   --> $DIR/as-ref.rs:13:35
    |
 LL |   opt.and_then(|arg| Ok(takes_ref(arg)));
-   |       -                           ^^^ expected &Foo, found struct `Foo`
+   |       --------                    ^^^ expected &Foo, found struct `Foo`
    |       |
-   |       help: consider using `as_ref` instead: `as_ref().`
+   |       help: consider using `as_ref` instead: `as_ref().and_then`
    |
    = note: expected type `&Foo`
               found type `Foo`
diff --git a/src/test/ui/suggestions/attribute-typos.rs b/src/test/ui/suggestions/attribute-typos.rs
new file mode 100644
index 0000000000000..13c6308b97e85
--- /dev/null
+++ b/src/test/ui/suggestions/attribute-typos.rs
@@ -0,0 +1,13 @@
+#[deprcated]    //~ ERROR E0658
+fn foo() {}     //~| HELP a built-in attribute with a similar name exists
+                //~| SUGGESTION deprecated
+                //~| HELP add #![feature(custom_attribute)] to the crate attributes to enable
+
+#[tests]        //~ ERROR E0658
+fn bar() {}     //~| HELP a built-in attribute with a similar name exists
+                //~| SUGGESTION test
+                //~| HELP add #![feature(custom_attribute)] to the crate attributes to enable
+
+#[rustc_err]    //~ ERROR E0658
+fn main() {}    //~| HELP add #![feature(rustc_attrs)] to the crate attributes to enable
+                // don't suggest rustc attributes
diff --git a/src/test/ui/suggestions/attribute-typos.stderr b/src/test/ui/suggestions/attribute-typos.stderr
new file mode 100644
index 0000000000000..e40da787e96ca
--- /dev/null
+++ b/src/test/ui/suggestions/attribute-typos.stderr
@@ -0,0 +1,27 @@
+error[E0658]: unless otherwise specified, attributes with the prefix `rustc_` are reserved for internal compiler diagnostics (see issue #29642)
+  --> $DIR/attribute-typos.rs:11:3
+   |
+LL | #[rustc_err]    //~ ERROR E0658
+   |   ^^^^^^^^^
+   |
+   = help: add #![feature(rustc_attrs)] to the crate attributes to enable
+
+error[E0658]: The attribute `tests` is currently unknown to the compiler and may have meaning added to it in the future (see issue #29642)
+  --> $DIR/attribute-typos.rs:6:3
+   |
+LL | #[tests]        //~ ERROR E0658
+   |   ^^^^^ help: a built-in attribute with a similar name exists: `test`
+   |
+   = help: add #![feature(custom_attribute)] to the crate attributes to enable
+
+error[E0658]: The attribute `deprcated` is currently unknown to the compiler and may have meaning added to it in the future (see issue #29642)
+  --> $DIR/attribute-typos.rs:1:3
+   |
+LL | #[deprcated]    //~ ERROR E0658
+   |   ^^^^^^^^^ help: a built-in attribute with a similar name exists: `deprecated`
+   |
+   = help: add #![feature(custom_attribute)] to the crate attributes to enable
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/suggestions/recover-invalid-float.rs b/src/test/ui/suggestions/recover-invalid-float.rs
new file mode 100644
index 0000000000000..506ef8900b881
--- /dev/null
+++ b/src/test/ui/suggestions/recover-invalid-float.rs
@@ -0,0 +1,11 @@
+fn main() {
+    let _: usize = .3;
+    //~^ ERROR float literals must have an integer part
+    //~| ERROR mismatched types
+    let _: usize = .42f32;
+    //~^ ERROR float literals must have an integer part
+    //~| ERROR mismatched types
+    let _: usize = .5f64;
+    //~^ ERROR float literals must have an integer part
+    //~| ERROR mismatched types
+}
diff --git a/src/test/ui/suggestions/recover-invalid-float.stderr b/src/test/ui/suggestions/recover-invalid-float.stderr
new file mode 100644
index 0000000000000..c464676b444cc
--- /dev/null
+++ b/src/test/ui/suggestions/recover-invalid-float.stderr
@@ -0,0 +1,42 @@
+error: float literals must have an integer part
+  --> $DIR/recover-invalid-float.rs:2:20
+   |
+LL |     let _: usize = .3;
+   |                    ^^ help: must have an integer part: `0.3`
+
+error: float literals must have an integer part
+  --> $DIR/recover-invalid-float.rs:5:20
+   |
+LL |     let _: usize = .42f32;
+   |                    ^^^^^^ help: must have an integer part: `0.42f32`
+
+error: float literals must have an integer part
+  --> $DIR/recover-invalid-float.rs:8:20
+   |
+LL |     let _: usize = .5f64;
+   |                    ^^^^^ help: must have an integer part: `0.5f64`
+
+error[E0308]: mismatched types
+  --> $DIR/recover-invalid-float.rs:2:20
+   |
+LL |     let _: usize = .3;
+   |                    ^^ expected usize, found floating-point number
+   |
+   = note: expected type `usize`
+              found type `{float}`
+
+error[E0308]: mismatched types
+  --> $DIR/recover-invalid-float.rs:5:20
+   |
+LL |     let _: usize = .42f32;
+   |                    ^^^^^^ expected usize, found f32
+
+error[E0308]: mismatched types
+  --> $DIR/recover-invalid-float.rs:8:20
+   |
+LL |     let _: usize = .5f64;
+   |                    ^^^^^ expected usize, found f64
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/suggest-methods.stderr b/src/test/ui/suggestions/suggest-methods.stderr
index 39d96a943a18a..b7727cf03a4e7 100644
--- a/src/test/ui/suggestions/suggest-methods.stderr
+++ b/src/test/ui/suggestions/suggest-methods.stderr
@@ -5,25 +5,19 @@ LL | struct Foo;
    | ----------- method `bat` not found for this
 ...
 LL |     f.bat(1.0); //~ ERROR no method named
-   |       ^^^
-   |
-   = help: did you mean `bar`?
+   |       ^^^ help: did you mean: `bar`
 
 error[E0599]: no method named `is_emtpy` found for type `std::string::String` in the current scope
   --> $DIR/suggest-methods.rs:21:15
    |
 LL |     let _ = s.is_emtpy(); //~ ERROR no method named
-   |               ^^^^^^^^
-   |
-   = help: did you mean `is_empty`?
+   |               ^^^^^^^^ help: did you mean: `is_empty`
 
 error[E0599]: no method named `count_eos` found for type `u32` in the current scope
   --> $DIR/suggest-methods.rs:25:19
    |
 LL |     let _ = 63u32.count_eos(); //~ ERROR no method named
-   |                   ^^^^^^^^^
-   |
-   = help: did you mean `count_zeros`?
+   |                   ^^^^^^^^^ help: did you mean: `count_zeros`
 
 error[E0599]: no method named `count_o` found for type `u32` in the current scope
   --> $DIR/suggest-methods.rs:28:19
diff --git a/src/test/ui/suggestions/suggest-move-lifetimes.stderr b/src/test/ui/suggestions/suggest-move-lifetimes.stderr
index 72a2cbe6bf6de..2d6dee0621662 100644
--- a/src/test/ui/suggestions/suggest-move-lifetimes.stderr
+++ b/src/test/ui/suggestions/suggest-move-lifetimes.stderr
@@ -2,41 +2,25 @@ error: lifetime parameters must be declared prior to type parameters
   --> $DIR/suggest-move-lifetimes.rs:1:13
    |
 LL | struct A<T, 'a> { //~ ERROR lifetime parameters must be declared
-   |             ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | struct A<'a, T> { //~ ERROR lifetime parameters must be declared
-   |          ^^^ --
+   |         ----^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, T>`
 
 error: lifetime parameters must be declared prior to type parameters
   --> $DIR/suggest-move-lifetimes.rs:5:13
    |
 LL | struct B<T, 'a, U> { //~ ERROR lifetime parameters must be declared
-   |             ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | struct B<'a, T, U> { //~ ERROR lifetime parameters must be declared
-   |          ^^^   --
+   |         ----^^---- help: reorder the parameters: lifetimes, then types, then consts: `<'a, T, U>`
 
 error: lifetime parameters must be declared prior to type parameters
   --> $DIR/suggest-move-lifetimes.rs:10:16
    |
 LL | struct C<T, U, 'a> { //~ ERROR lifetime parameters must be declared
-   |                ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | struct C<'a, T, U> { //~ ERROR lifetime parameters must be declared
-   |          ^^^    --
+   |         -------^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, T, U>`
 
 error: lifetime parameters must be declared prior to type parameters
   --> $DIR/suggest-move-lifetimes.rs:15:16
    |
 LL | struct D<T, U, 'a, 'b, V, 'c> { //~ ERROR lifetime parameters must be declared
-   |                ^^  ^^     ^^
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL | struct D<'a, 'b, 'c, T, U, V> { //~ ERROR lifetime parameters must be declared
-   |          ^^^ ^^^ ^^^      ---
+   |         -------^^--^^-----^^- help: reorder the parameters: lifetimes, then types, then consts: `<'a, 'b, 'c, T, U, V>`
 
 error: aborting due to 4 previous errors
 
diff --git a/src/test/ui/suggestions/suggest-move-types.rs b/src/test/ui/suggestions/suggest-move-types.rs
new file mode 100644
index 0000000000000..890950ea08c5d
--- /dev/null
+++ b/src/test/ui/suggestions/suggest-move-types.rs
@@ -0,0 +1,89 @@
+// ignore-tidy-linelength
+
+#![allow(warnings)]
+
+// This test verifies that the suggestion to move types before associated type bindings
+// is correct.
+
+trait One<T> {
+  type A;
+}
+
+trait OneWithLifetime<'a, T> {
+  type A;
+}
+
+trait Three<T, U, V> {
+  type A;
+  type B;
+  type C;
+}
+
+trait ThreeWithLifetime<'a, 'b, 'c, T, U, V> {
+  type A;
+  type B;
+  type C;
+}
+
+struct A<T, M: One<A=(), T>> { //~ ERROR associated type bindings must be declared after generic parameters
+    m: M,
+    t: T,
+}
+
+
+struct Al<'a, T, M: OneWithLifetime<A=(), T, 'a>> {
+//~^ ERROR associated type bindings must be declared after generic parameters
+//~^^ ERROR lifetime arguments must be declared prior to type arguments
+    m: M,
+    t: &'a T,
+}
+
+struct B<T, U, V, M: Three<A=(), B=(), C=(), T, U, V>> { //~ ERROR associated type bindings must be declared after generic parameters
+    m: M,
+    t: T,
+    u: U,
+    v: V,
+}
+
+struct Bl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), C=(), T, U, V, 'a, 'b, 'c>> {
+//~^ ERROR associated type bindings must be declared after generic parameters
+//~^^ ERROR lifetime arguments must be declared prior to type arguments
+    m: M,
+    t: &'a T,
+    u: &'b U,
+    v: &'c V,
+}
+
+struct C<T, U, V, M: Three<T, A=(), B=(), C=(), U, V>> { //~ ERROR associated type bindings must be declared after generic parameters
+    m: M,
+    t: T,
+    u: U,
+    v: V,
+}
+
+struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=(), U, 'b, V, 'c>> {
+//~^ ERROR associated type bindings must be declared after generic parameters
+//~^^ ERROR lifetime arguments must be declared prior to type arguments
+    m: M,
+    t: &'a T,
+    u: &'b U,
+    v: &'c V,
+}
+
+struct D<T, U, V, M: Three<T, A=(), B=(), U, C=(), V>> { //~ ERROR associated type bindings must be declared after generic parameters
+    m: M,
+    t: T,
+    u: U,
+    v: V,
+}
+
+struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, 'b, C=(), V, 'c>> {
+//~^ ERROR associated type bindings must be declared after generic parameters
+//~^^ ERROR lifetime arguments must be declared prior to type arguments
+    m: M,
+    t: &'a T,
+    u: &'b U,
+    v: &'c V,
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/suggest-move-types.stderr b/src/test/ui/suggestions/suggest-move-types.stderr
new file mode 100644
index 0000000000000..0901b71911d43
--- /dev/null
+++ b/src/test/ui/suggestions/suggest-move-types.stderr
@@ -0,0 +1,102 @@
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:28:20
+   |
+LL | struct A<T, M: One<A=(), T>> { //~ ERROR associated type bindings must be declared after generic parameters
+   |                    ----^^^
+   |                    |
+   |                    this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:34:37
+   |
+LL | struct Al<'a, T, M: OneWithLifetime<A=(), T, 'a>> {
+   |                                     ----^^^^^^^
+   |                                     |
+   |                                     this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:41:28
+   |
+LL | struct B<T, U, V, M: Three<A=(), B=(), C=(), T, U, V>> { //~ ERROR associated type bindings must be declared after generic parameters
+   |                            ----^^----^^----^^^^^^^^^
+   |                            |     |     |
+   |                            |     |     this associated type binding should be moved after the generic parameters
+   |                            |     this associated type binding should be moved after the generic parameters
+   |                            this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:48:53
+   |
+LL | struct Bl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), C=(), T, U, V, 'a, 'b, 'c>> {
+   |                                                     ----^^----^^----^^^^^^^^^^^^^^^^^^^^^
+   |                                                     |     |     |
+   |                                                     |     |     this associated type binding should be moved after the generic parameters
+   |                                                     |     this associated type binding should be moved after the generic parameters
+   |                                                     this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:57:28
+   |
+LL | struct C<T, U, V, M: Three<T, A=(), B=(), C=(), U, V>> { //~ ERROR associated type bindings must be declared after generic parameters
+   |                            ^^^----^^----^^----^^^^^^
+   |                               |     |     |
+   |                               |     |     this associated type binding should be moved after the generic parameters
+   |                               |     this associated type binding should be moved after the generic parameters
+   |                               this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:64:53
+   |
+LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=(), U, 'b, V, 'c>> {
+   |                                                     ^^^^^^^----^^----^^----^^^^^^^^^^^^^^
+   |                                                            |     |     |
+   |                                                            |     |     this associated type binding should be moved after the generic parameters
+   |                                                            |     this associated type binding should be moved after the generic parameters
+   |                                                            this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:73:28
+   |
+LL | struct D<T, U, V, M: Three<T, A=(), B=(), U, C=(), V>> { //~ ERROR associated type bindings must be declared after generic parameters
+   |                            ^^^----^^----^^^^^----^^^
+   |                               |     |        |
+   |                               |     |        this associated type binding should be moved after the generic parameters
+   |                               |     this associated type binding should be moved after the generic parameters
+   |                               this associated type binding should be moved after the generic parameters
+
+error: associated type bindings must be declared after generic parameters
+  --> $DIR/suggest-move-types.rs:80:53
+   |
+LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, 'b, C=(), V, 'c>> {
+   |                                                     ^^^^^^^----^^----^^^^^^^^^----^^^^^^^
+   |                                                            |     |            |
+   |                                                            |     |            this associated type binding should be moved after the generic parameters
+   |                                                            |     this associated type binding should be moved after the generic parameters
+   |                                                            this associated type binding should be moved after the generic parameters
+
+error: lifetime arguments must be declared prior to type arguments
+  --> $DIR/suggest-move-types.rs:34:46
+   |
+LL | struct Al<'a, T, M: OneWithLifetime<A=(), T, 'a>> {
+   |                                              ^^
+
+error: lifetime arguments must be declared prior to type arguments
+  --> $DIR/suggest-move-types.rs:48:80
+   |
+LL | struct Bl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<A=(), B=(), C=(), T, U, V, 'a, 'b, 'c>> {
+   |                                                                                ^^  ^^  ^^
+
+error: lifetime arguments must be declared prior to type arguments
+  --> $DIR/suggest-move-types.rs:64:56
+   |
+LL | struct Cl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), C=(), U, 'b, V, 'c>> {
+   |                                                        ^^                       ^^     ^^
+
+error: lifetime arguments must be declared prior to type arguments
+  --> $DIR/suggest-move-types.rs:80:56
+   |
+LL | struct Dl<'a, 'b, 'c, T, U, V, M: ThreeWithLifetime<T, 'a, A=(), B=(), U, 'b, C=(), V, 'c>> {
+   |                                                        ^^                 ^^           ^^
+
+error: aborting due to 12 previous errors
+
diff --git a/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.rs b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.rs
new file mode 100644
index 0000000000000..2ce12220723df
--- /dev/null
+++ b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.rs
@@ -0,0 +1,9 @@
+struct RGB { r: f64, g: f64, b: f64 }
+
+fn main() {
+    let (r, g, c): (f32, f32, f32) = (0., 0., 0.);
+    let _ = RGB { r, g, c };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    //~| ERROR struct `RGB` has no field named `c`
+}
diff --git a/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.stderr b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.stderr
new file mode 100644
index 0000000000000..d0f9e1f7f7c8e
--- /dev/null
+++ b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand-2.stderr
@@ -0,0 +1,30 @@
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-struct-field-shorthand-2.rs:5:19
+   |
+LL |     let _ = RGB { r, g, c };
+   |                   ^ expected f64, found f32
+help: you can cast an `f32` to `f64` in a lossless way
+   |
+LL |     let _ = RGB { r: r.into(), g, c };
+   |                   ^^^^^^^^^^^
+
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-struct-field-shorthand-2.rs:5:22
+   |
+LL |     let _ = RGB { r, g, c };
+   |                      ^ expected f64, found f32
+help: you can cast an `f32` to `f64` in a lossless way
+   |
+LL |     let _ = RGB { r, g: g.into(), c };
+   |                      ^^^^^^^^^^^
+
+error[E0560]: struct `RGB` has no field named `c`
+  --> $DIR/type-mismatch-struct-field-shorthand-2.rs:5:25
+   |
+LL |     let _ = RGB { r, g, c };
+   |                         ^ help: a field with a similar name exists: `b`
+
+error: aborting due to 3 previous errors
+
+Some errors occurred: E0308, E0560.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.fixed b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.fixed
new file mode 100644
index 0000000000000..91758c0b21882
--- /dev/null
+++ b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.fixed
@@ -0,0 +1,12 @@
+// run-rustfix
+#![allow(dead_code)]
+
+struct RGB { r: f64, g: f64, b: f64 }
+
+fn main() {
+    let (r, g, b): (f32, f32, f32) = (0., 0., 0.);
+    let _ = RGB { r: r.into(), g: g.into(), b: b.into() };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    //~| ERROR mismatched types
+}
diff --git a/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.rs b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.rs
new file mode 100644
index 0000000000000..9d3a17a72b21e
--- /dev/null
+++ b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.rs
@@ -0,0 +1,12 @@
+// run-rustfix
+#![allow(dead_code)]
+
+struct RGB { r: f64, g: f64, b: f64 }
+
+fn main() {
+    let (r, g, b): (f32, f32, f32) = (0., 0., 0.);
+    let _ = RGB { r, g, b };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    //~| ERROR mismatched types
+}
diff --git a/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.stderr b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.stderr
new file mode 100644
index 0000000000000..6bc16ba8b70fa
--- /dev/null
+++ b/src/test/ui/suggestions/type-mismatch-struct-field-shorthand.stderr
@@ -0,0 +1,33 @@
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-struct-field-shorthand.rs:8:19
+   |
+LL |     let _ = RGB { r, g, b };
+   |                   ^ expected f64, found f32
+help: you can cast an `f32` to `f64` in a lossless way
+   |
+LL |     let _ = RGB { r: r.into(), g, b };
+   |                   ^^^^^^^^^^^
+
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-struct-field-shorthand.rs:8:22
+   |
+LL |     let _ = RGB { r, g, b };
+   |                      ^ expected f64, found f32
+help: you can cast an `f32` to `f64` in a lossless way
+   |
+LL |     let _ = RGB { r, g: g.into(), b };
+   |                      ^^^^^^^^^^^
+
+error[E0308]: mismatched types
+  --> $DIR/type-mismatch-struct-field-shorthand.rs:8:25
+   |
+LL |     let _ = RGB { r, g, b };
+   |                         ^ expected f64, found f32
+help: you can cast an `f32` to `f64` in a lossless way
+   |
+LL |     let _ = RGB { r, g, b: b.into() };
+   |                         ^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/svh/auxiliary/svh-b.rs b/src/test/ui/svh/auxiliary/svh-b.rs
index 03869aeb37194..57029f70888b3 100644
--- a/src/test/ui/svh/auxiliary/svh-b.rs
+++ b/src/test/ui/svh/auxiliary/svh-b.rs
@@ -1,7 +1,7 @@
-//! This is a client of the `a` crate defined in "svn-a-base.rs".  The
-//! rpass and cfail tests (such as "run-pass/svh-add-comment.rs") use
+//! This is a client of the `a` crate defined in `svn-a-base.rs`. The
+//! rpass and cfail tests (such as `run-pass/svh-add-comment.rs`) use
 //! it by swapping in a different object code library crate built from
-//! some variant of "svn-a-base.rs", and then we are checking if the
+//! some variant of `svn-a-base.rs`, and then we are checking if the
 //! compiler properly ignores or accepts the change, based on whether
 //! the change could affect the downstream crate content or not
 //! (#14132).
diff --git a/src/test/ui/tail-typeck.stderr b/src/test/ui/tail-typeck.stderr
index eadf3d6d3350e..1170f5c17c18a 100644
--- a/src/test/ui/tail-typeck.stderr
+++ b/src/test/ui/tail-typeck.stderr
@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/tail-typeck.rs:3:26
    |
 LL | fn f() -> isize { return g(); }
-   |                          ^^^ expected isize, found usize
+   |           -----          ^^^ expected isize, found usize
+   |           |
+   |           expected `isize` because of return type
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/target-feature-gate.rs b/src/test/ui/target-feature-gate.rs
index 30fb534dbb591..84300301b7629 100644
--- a/src/test/ui/target-feature-gate.rs
+++ b/src/test/ui/target-feature-gate.rs
@@ -22,6 +22,7 @@
 // gate-test-wasm_target_feature
 // gate-test-adx_target_feature
 // gate-test-cmpxchg16b_target_feature
+// gate-test-movbe_target_feature
 // min-llvm-version 6.0
 
 #[target_feature(enable = "avx512bw")]
diff --git a/src/test/ui/target-feature-gate.stderr b/src/test/ui/target-feature-gate.stderr
index 8dfb4f65f98c4..24141d0064fb0 100644
--- a/src/test/ui/target-feature-gate.stderr
+++ b/src/test/ui/target-feature-gate.stderr
@@ -1,5 +1,5 @@
 error[E0658]: the target feature `avx512bw` is currently unstable (see issue #44839)
-  --> $DIR/target-feature-gate.rs:27:18
+  --> $DIR/target-feature-gate.rs:28:18
    |
 LL | #[target_feature(enable = "avx512bw")]
    |                  ^^^^^^^^^^^^^^^^^^^
diff --git a/src/test/ui/thread-local-mutation.nll.stderr b/src/test/ui/thread-local-mutation.nll.stderr
new file mode 100644
index 0000000000000..0a3664b0d9d40
--- /dev/null
+++ b/src/test/ui/thread-local-mutation.nll.stderr
@@ -0,0 +1,9 @@
+error[E0594]: cannot assign to immutable static item `S`
+  --> $DIR/thread-local-mutation.rs:11:5
+   |
+LL |     S = "after"; //~ ERROR cannot assign to immutable
+   |     ^^^^^^^^^^^ cannot assign
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0594`.
diff --git a/src/test/ui/thread-local-mutation.rs b/src/test/ui/thread-local-mutation.rs
new file mode 100644
index 0000000000000..e738225ce2a48
--- /dev/null
+++ b/src/test/ui/thread-local-mutation.rs
@@ -0,0 +1,18 @@
+// Regression test for #54901: immutable thread locals could be mutated. See:
+// https://github.com/rust-lang/rust/issues/29594#issuecomment-328177697
+// https://github.com/rust-lang/rust/issues/54901
+
+#![feature(thread_local)]
+
+#[thread_local]
+static S: &str = "before";
+
+fn set_s() {
+    S = "after"; //~ ERROR cannot assign to immutable
+}
+
+fn main() {
+    println!("{}", S);
+    set_s();
+    println!("{}", S);
+}
diff --git a/src/test/ui/thread-local-mutation.stderr b/src/test/ui/thread-local-mutation.stderr
new file mode 100644
index 0000000000000..bf298523e1b73
--- /dev/null
+++ b/src/test/ui/thread-local-mutation.stderr
@@ -0,0 +1,9 @@
+error[E0594]: cannot assign to immutable thread-local static item
+  --> $DIR/thread-local-mutation.rs:11:5
+   |
+LL |     S = "after"; //~ ERROR cannot assign to immutable
+   |     ^^^^^^^^^^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0594`.
diff --git a/src/test/ui/traits/auxiliary/trait_alias.rs b/src/test/ui/traits/auxiliary/trait_alias.rs
new file mode 100644
index 0000000000000..9e56b87e08813
--- /dev/null
+++ b/src/test/ui/traits/auxiliary/trait_alias.rs
@@ -0,0 +1,3 @@
+#![feature(trait_alias)]
+
+pub trait SendSync = Send + Sync;
diff --git a/src/test/ui/traits/trait-alias-cross-crate.rs b/src/test/ui/traits/trait-alias-cross-crate.rs
new file mode 100644
index 0000000000000..259fc4fa5d1ce
--- /dev/null
+++ b/src/test/ui/traits/trait-alias-cross-crate.rs
@@ -0,0 +1,17 @@
+// aux-build:trait_alias.rs
+
+#![feature(trait_alias)]
+
+extern crate trait_alias;
+
+use std::rc::Rc;
+use trait_alias::SendSync;
+
+fn use_alias<T: SendSync>() {}
+
+fn main() {
+    use_alias::<u32>();
+    use_alias::<Rc<u32>>();
+    //~^ ERROR `std::rc::Rc<u32>` cannot be sent between threads safely [E0277]
+    //~^^ ERROR `std::rc::Rc<u32>` cannot be shared between threads safely [E0277]
+}
diff --git a/src/test/ui/traits/trait-alias-cross-crate.stderr b/src/test/ui/traits/trait-alias-cross-crate.stderr
new file mode 100644
index 0000000000000..972d213ac8f8f
--- /dev/null
+++ b/src/test/ui/traits/trait-alias-cross-crate.stderr
@@ -0,0 +1,29 @@
+error[E0277]: `std::rc::Rc<u32>` cannot be sent between threads safely
+  --> $DIR/trait-alias-cross-crate.rs:14:5
+   |
+LL |     use_alias::<Rc<u32>>();
+   |     ^^^^^^^^^^^^^^^^^^^^ `std::rc::Rc<u32>` cannot be sent between threads safely
+   |
+   = help: the trait `std::marker::Send` is not implemented for `std::rc::Rc<u32>`
+note: required by `use_alias`
+  --> $DIR/trait-alias-cross-crate.rs:10:1
+   |
+LL | fn use_alias<T: SendSync>() {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: `std::rc::Rc<u32>` cannot be shared between threads safely
+  --> $DIR/trait-alias-cross-crate.rs:14:5
+   |
+LL |     use_alias::<Rc<u32>>();
+   |     ^^^^^^^^^^^^^^^^^^^^ `std::rc::Rc<u32>` cannot be shared between threads safely
+   |
+   = help: the trait `std::marker::Sync` is not implemented for `std::rc::Rc<u32>`
+note: required by `use_alias`
+  --> $DIR/trait-alias-cross-crate.rs:10:1
+   |
+LL | fn use_alias<T: SendSync>() {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/traits/trait-alias-syntax.rs b/src/test/ui/traits/trait-alias-syntax.rs
new file mode 100644
index 0000000000000..5948d45b6987f
--- /dev/null
+++ b/src/test/ui/traits/trait-alias-syntax.rs
@@ -0,0 +1,7 @@
+#![feature(trait_alias)]
+
+trait Foo {}
+auto trait A = Foo; //~ ERROR trait aliases cannot be `auto`
+unsafe trait B = Foo; //~ ERROR trait aliases cannot be `unsafe`
+
+fn main() {}
diff --git a/src/test/ui/traits/trait-alias-syntax.stderr b/src/test/ui/traits/trait-alias-syntax.stderr
new file mode 100644
index 0000000000000..fc96f6274393d
--- /dev/null
+++ b/src/test/ui/traits/trait-alias-syntax.stderr
@@ -0,0 +1,14 @@
+error: trait aliases cannot be `auto`
+  --> $DIR/trait-alias-syntax.rs:4:19
+   |
+LL | auto trait A = Foo; //~ ERROR trait aliases cannot be `auto`
+   |                   ^ trait aliases cannot be `auto`
+
+error: trait aliases cannot be `unsafe`
+  --> $DIR/trait-alias-syntax.rs:5:21
+   |
+LL | unsafe trait B = Foo; //~ ERROR trait aliases cannot be `unsafe`
+   |                     ^ trait aliases cannot be `unsafe`
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/traits/trait-object-vs-lifetime.rs b/src/test/ui/traits/trait-object-vs-lifetime.rs
index a12429c868ed0..36dec21be0520 100644
--- a/src/test/ui/traits/trait-object-vs-lifetime.rs
+++ b/src/test/ui/traits/trait-object-vs-lifetime.rs
@@ -12,6 +12,6 @@ fn main() {
     //~^ ERROR wrong number of lifetime arguments: expected 1, found 2
     //~| ERROR wrong number of type arguments: expected 1, found 0
     let _: S<'static +, 'static>;
-    //~^ ERROR lifetime parameters must be declared prior to type parameters
+    //~^ ERROR lifetime arguments must be declared prior to type arguments
     //~| ERROR at least one non-builtin trait is required for an object type
 }
diff --git a/src/test/ui/traits/trait-object-vs-lifetime.stderr b/src/test/ui/traits/trait-object-vs-lifetime.stderr
index 4cc96bae5cd17..e0c52a72a0931 100644
--- a/src/test/ui/traits/trait-object-vs-lifetime.stderr
+++ b/src/test/ui/traits/trait-object-vs-lifetime.stderr
@@ -1,12 +1,8 @@
-error: lifetime parameters must be declared prior to type parameters
+error: lifetime arguments must be declared prior to type arguments
   --> $DIR/trait-object-vs-lifetime.rs:14:25
    |
 LL |     let _: S<'static +, 'static>;
-   |                         ^^^^^^^ must be declared prior to type parameters
-help: move the lifetime parameter prior to the first type parameter
-   |
-LL |     let _: S<'static, 'static +>;
-   |              ^^^^^^^^         --
+   |                         ^^^^^^^
 
 error[E0224]: at least one non-builtin trait is required for an object type
   --> $DIR/trait-object-vs-lifetime.rs:9:23
diff --git a/src/test/ui/traits/trait-privacy.rs b/src/test/ui/traits/trait-privacy.rs
index 523211fea9368..6254157e25da3 100644
--- a/src/test/ui/traits/trait-privacy.rs
+++ b/src/test/ui/traits/trait-privacy.rs
@@ -1,5 +1,4 @@
 // compile-pass
-#![feature(get_type_id)]
 #![allow(dead_code)]
 mod foo {
     pub use self::bar::T;
@@ -18,7 +17,7 @@ fn g() {
 
 fn f() {
     let error = ::std::thread::spawn(|| {}).join().unwrap_err();
-    error.get_type_id(); // Regression test for #21670
+    error.type_id(); // Regression test for #21670
 }
 
 
diff --git a/src/test/ui/try-block/try-block-bad-lifetime.stderr b/src/test/ui/try-block/try-block-bad-lifetime.stderr
index 5bb0b099b977b..b1b925d694ff9 100644
--- a/src/test/ui/try-block/try-block-bad-lifetime.stderr
+++ b/src/test/ui/try-block/try-block-bad-lifetime.stderr
@@ -25,13 +25,14 @@ LL |         ::std::mem::drop(k); //~ ERROR use of moved value: `k`
 error[E0382]: use of moved value: `k`
   --> $DIR/try-block-bad-lifetime.rs:31:26
    |
+LL |         let k = &mut i;
+   |             - move occurs because `k` has type `&mut i32`, which does not implement the `Copy` trait
+LL |         let mut j: Result<(), &mut i32> = try {
 LL |             Err(k) ?;
    |                 - value moved here
 ...
 LL |         ::std::mem::drop(k); //~ ERROR use of moved value: `k`
    |                          ^ value used here after move
-   |
-   = note: move occurs because `k` has type `&mut i32`, which does not implement the `Copy` trait
 
 error[E0506]: cannot assign to `i` because it is borrowed
   --> $DIR/try-block-bad-lifetime.rs:32:9
diff --git a/src/test/ui/try-block/try-block-bad-type.stderr b/src/test/ui/try-block/try-block-bad-type.stderr
index 202885e383ece..df8e646280c9a 100644
--- a/src/test/ui/try-block/try-block-bad-type.stderr
+++ b/src/test/ui/try-block/try-block-bad-type.stderr
@@ -6,10 +6,10 @@ LL |         Err("")?; //~ ERROR the trait bound `i32: std::convert::From<&str>`
    |
    = help: the following implementations were found:
              <i32 as std::convert::From<bool>>
+             <i32 as std::convert::From<core::num::NonZeroI32>>
              <i32 as std::convert::From<i16>>
              <i32 as std::convert::From<i8>>
-             <i32 as std::convert::From<u16>>
-             <i32 as std::convert::From<u8>>
+           and 2 others
    = note: required by `std::convert::From::from`
 
 error[E0271]: type mismatch resolving `<std::result::Result<i32, i32> as std::ops::Try>::Ok == &str`
diff --git a/src/test/ui/try-block/try-block-in-edition2015.stderr b/src/test/ui/try-block/try-block-in-edition2015.stderr
index 63650086bcaa9..7394fec6f3660 100644
--- a/src/test/ui/try-block/try-block-in-edition2015.stderr
+++ b/src/test/ui/try-block/try-block-in-edition2015.stderr
@@ -15,7 +15,9 @@ error[E0574]: expected struct, variant or union type, found macro `try`
   --> $DIR/try-block-in-edition2015.rs:4:33
    |
 LL |     let try_result: Option<_> = try {
-   |                                 ^^^ did you mean `try!(...)`?
+   |                                 ^^^ help: use `!` to invoke the macro: `try!`
+   |
+   = note: if you want the `try` keyword, you need to be in the 2018 edition
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/try-block/try-block-maybe-bad-lifetime.stderr b/src/test/ui/try-block/try-block-maybe-bad-lifetime.stderr
index f96c7146d18d0..dafbde6a5150b 100644
--- a/src/test/ui/try-block/try-block-maybe-bad-lifetime.stderr
+++ b/src/test/ui/try-block/try-block-maybe-bad-lifetime.stderr
@@ -13,13 +13,14 @@ LL |         do_something_with(x);
 error[E0382]: borrow of moved value: `x`
   --> $DIR/try-block-maybe-bad-lifetime.rs:28:24
    |
+LL |         let x = String::new();
+   |             - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
+...
 LL |             ::std::mem::drop(x);
    |                              - value moved here
 LL |         };
 LL |         println!("{}", x); //~ ERROR borrow of moved value: `x`
    |                        ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error[E0506]: cannot assign to `i` because it is borrowed
   --> $DIR/try-block-maybe-bad-lifetime.rs:40:9
diff --git a/src/test/ui/type-alias-enum-variants-priority-2.rs b/src/test/ui/type-alias-enum-variants-priority-2.rs
new file mode 100644
index 0000000000000..295f8acf62f85
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority-2.rs
@@ -0,0 +1,13 @@
+#![feature(type_alias_enum_variants)]
+
+enum E {
+    V(u8)
+}
+
+impl E {
+    fn V() {}
+}
+
+fn main() {
+    <E>::V(); //~ ERROR this function takes 1 parameter but 0 parameters were supplied
+}
diff --git a/src/test/ui/type-alias-enum-variants-priority-2.stderr b/src/test/ui/type-alias-enum-variants-priority-2.stderr
new file mode 100644
index 0000000000000..c6ec96ebb7d3b
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority-2.stderr
@@ -0,0 +1,12 @@
+error[E0061]: this function takes 1 parameter but 0 parameters were supplied
+  --> $DIR/type-alias-enum-variants-priority-2.rs:12:5
+   |
+LL |     V(u8)
+   |     ----- defined here
+...
+LL |     <E>::V(); //~ ERROR this function takes 1 parameter but 0 parameters were supplied
+   |     ^^^^^^^^ expected 1 parameter
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0061`.
diff --git a/src/test/ui/type-alias-enum-variants-priority-3.rs b/src/test/ui/type-alias-enum-variants-priority-3.rs
new file mode 100644
index 0000000000000..33f96553b57f0
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority-3.rs
@@ -0,0 +1,10 @@
+#![feature(type_alias_enum_variants)]
+
+enum E {
+    V
+}
+
+fn check() -> <E>::V {}
+//~^ ERROR expected type, found variant `V`
+
+fn main() {}
diff --git a/src/test/ui/type-alias-enum-variants-priority-3.stderr b/src/test/ui/type-alias-enum-variants-priority-3.stderr
new file mode 100644
index 0000000000000..b3451542a2570
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority-3.stderr
@@ -0,0 +1,8 @@
+error: expected type, found variant `V`
+  --> $DIR/type-alias-enum-variants-priority-3.rs:7:15
+   |
+LL | fn check() -> <E>::V {}
+   |               ^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/type-alias-enum-variants-priority.rs b/src/test/ui/type-alias-enum-variants-priority.rs
new file mode 100644
index 0000000000000..db1da2b12e256
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority.rs
@@ -0,0 +1,20 @@
+#![feature(type_alias_enum_variants)]
+#![deny(ambiguous_associated_items)]
+
+enum E {
+    V
+}
+
+trait Tr {
+    type V;
+    fn f() -> Self::V;
+}
+
+impl Tr for E {
+    type V = u8;
+    fn f() -> Self::V { 0 }
+    //~^ ERROR ambiguous associated item
+    //~| WARN this was previously accepted
+}
+
+fn main() {}
diff --git a/src/test/ui/type-alias-enum-variants-priority.stderr b/src/test/ui/type-alias-enum-variants-priority.stderr
new file mode 100644
index 0000000000000..dcf7dc77ed5ea
--- /dev/null
+++ b/src/test/ui/type-alias-enum-variants-priority.stderr
@@ -0,0 +1,26 @@
+error: ambiguous associated item
+  --> $DIR/type-alias-enum-variants-priority.rs:15:15
+   |
+LL |     fn f() -> Self::V { 0 }
+   |               ^^^^^^^ help: use fully-qualified syntax: `<E as Trait>::V`
+   |
+note: lint level defined here
+  --> $DIR/type-alias-enum-variants-priority.rs:2:9
+   |
+LL | #![deny(ambiguous_associated_items)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #57644 <https://github.com/rust-lang/rust/issues/57644>
+note: `V` could refer to variant defined here
+  --> $DIR/type-alias-enum-variants-priority.rs:5:5
+   |
+LL |     V
+   |     ^
+note: `V` could also refer to associated type defined here
+  --> $DIR/type-alias-enum-variants-priority.rs:9:5
+   |
+LL |     type V;
+   |     ^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/type/type-arg-out-of-scope.rs b/src/test/ui/type/type-arg-out-of-scope.rs
index b96c9bf6a0e41..d5b815f6a95e9 100644
--- a/src/test/ui/type/type-arg-out-of-scope.rs
+++ b/src/test/ui/type/type-arg-out-of-scope.rs
@@ -1,4 +1,4 @@
-// error-pattern:can't use type parameters from outer function
+// error-pattern:can't use generic parameters from outer function
 fn foo<T>(x: T) {
     fn bar(f: Box<FnMut(T) -> T>) { }
 }
diff --git a/src/test/ui/type/type-arg-out-of-scope.stderr b/src/test/ui/type/type-arg-out-of-scope.stderr
index 62b6a86662d04..645cbb33abec1 100644
--- a/src/test/ui/type/type-arg-out-of-scope.stderr
+++ b/src/test/ui/type/type-arg-out-of-scope.stderr
@@ -1,22 +1,22 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/type-arg-out-of-scope.rs:3:25
    |
 LL | fn foo<T>(x: T) {
    |        - type variable from outer function
 LL |     fn bar(f: Box<FnMut(T) -> T>) { }
-   |        ---              ^ use of type variable from outer function
+   |        ---              ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `bar<T>`
+   |        help: try using a local generic parameter instead: `bar<T>`
 
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/type-arg-out-of-scope.rs:3:31
    |
 LL | fn foo<T>(x: T) {
    |        - type variable from outer function
 LL |     fn bar(f: Box<FnMut(T) -> T>) { }
-   |        ---                    ^ use of type variable from outer function
+   |        ---                    ^ use of generic parameter from outer function
    |        |
-   |        help: try using a local type parameter instead: `bar<T>`
+   |        help: try using a local generic parameter instead: `bar<T>`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/type/type-dependent-def-issue-49241.rs b/src/test/ui/type/type-dependent-def-issue-49241.rs
index 4c366a863637c..51bd116fbd61c 100644
--- a/src/test/ui/type/type-dependent-def-issue-49241.rs
+++ b/src/test/ui/type/type-dependent-def-issue-49241.rs
@@ -1,6 +1,6 @@
 fn main() {
     let v = vec![0];
-    const l: usize = v.count(); //~ ERROR can't capture dynamic environment in a fn item
+    const l: usize = v.count(); //~ ERROR attempt to use a non-constant value in a constant
     let s: [u32; l] = v.into_iter().collect();
     //~^ ERROR evaluation of constant value failed
 }
diff --git a/src/test/ui/type/type-dependent-def-issue-49241.stderr b/src/test/ui/type/type-dependent-def-issue-49241.stderr
index 8783959f45f5f..0af777fdcf907 100644
--- a/src/test/ui/type/type-dependent-def-issue-49241.stderr
+++ b/src/test/ui/type/type-dependent-def-issue-49241.stderr
@@ -1,10 +1,8 @@
-error[E0434]: can't capture dynamic environment in a fn item
+error[E0435]: attempt to use a non-constant value in a constant
   --> $DIR/type-dependent-def-issue-49241.rs:3:22
    |
-LL |     const l: usize = v.count(); //~ ERROR can't capture dynamic environment in a fn item
-   |                      ^
-   |
-   = help: use the `|| { ... }` closure form instead
+LL |     const l: usize = v.count(); //~ ERROR attempt to use a non-constant value in a constant
+   |                      ^ non-constant value
 
 error[E0080]: evaluation of constant value failed
   --> $DIR/type-dependent-def-issue-49241.rs:4:18
@@ -14,5 +12,5 @@ LL |     let s: [u32; l] = v.into_iter().collect();
 
 error: aborting due to 2 previous errors
 
-Some errors occurred: E0080, E0434.
+Some errors occurred: E0080, E0435.
 For more information about an error, try `rustc --explain E0080`.
diff --git a/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.rs b/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.rs
new file mode 100644
index 0000000000000..0a4e7da2bff50
--- /dev/null
+++ b/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.rs
@@ -0,0 +1,7 @@
+//extern crate has_assoc_type;
+
+//fn ice(x: Box<dyn has_assoc_type::Foo<Assoc=()>>) {
+fn ice(x: Box<dyn Iterator<Item=()>>) {
+    *x //~ ERROR mismatched types [E0308]
+}
+fn main() {}
diff --git a/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.stderr b/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.stderr
new file mode 100644
index 0000000000000..bb63917fc0860
--- /dev/null
+++ b/src/test/ui/typeck/issue-57673-ice-on-deref-of-boxed-trait.stderr
@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-57673-ice-on-deref-of-boxed-trait.rs:5:5
+   |
+LL | fn ice(x: Box<dyn Iterator<Item=()>>) {
+   |                                       - possibly return type missing here?
+LL |     *x //~ ERROR mismatched types [E0308]
+   |     ^^ expected (), found trait std::iter::Iterator
+   |
+   = note: expected type `()`
+              found type `(dyn std::iter::Iterator<Item=()> + 'static)`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.rs b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.rs
index 5387dcb218cb9..c96a6fa8b6c91 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.rs
@@ -6,7 +6,8 @@ struct Bar<A> {
 
 fn bar() {
     let x: Box<Bar()> = panic!();
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
+    //~| ERROR wrong number of type arguments: expected 1, found 0
 }
 
 fn main() { }
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.stderr b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.stderr
index 3f1b37c282b7c..fa52e66fb0349 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-1.stderr
@@ -1,9 +1,16 @@
-error[E0214]: parenthesized parameters may only be used with a trait
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/unboxed-closure-sugar-used-on-struct-1.rs:8:19
    |
 LL |     let x: Box<Bar()> = panic!();
-   |                   ^^ only traits may use parentheses
+   |                   ^^ only `Fn` traits may use parentheses
 
-error: aborting due to previous error
+error[E0107]: wrong number of type arguments: expected 1, found 0
+  --> $DIR/unboxed-closure-sugar-used-on-struct-1.rs:8:16
+   |
+LL |     let x: Box<Bar()> = panic!();
+   |                ^^^^^ expected 1 type argument
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0214`.
+Some errors occurred: E0107, E0214.
+For more information about an error, try `rustc --explain E0107`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.rs b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.rs
index 3cada322b1ef2..79ced1ecfb1a0 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.rs
@@ -12,7 +12,7 @@ fn bar() {
     let b = Bar::<isize, usize>::new(); // OK
 
     let b = Bar::(isize, usize)::new(); // OK too (for the parser)
-    //~^ ERROR parenthesized parameters may only be used with a trait
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
 }
 
 fn main() {}
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
index 395f6596cfd83..7d05ca55ffdb0 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct-3.stderr
@@ -1,8 +1,11 @@
-error[E0214]: parenthesized parameters may only be used with a trait
-  --> $DIR/unboxed-closure-sugar-used-on-struct-3.rs:14:16
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
+  --> $DIR/unboxed-closure-sugar-used-on-struct-3.rs:14:18
    |
 LL |     let b = Bar::(isize, usize)::new(); // OK too (for the parser)
-   |                ^^^^^^^^^^^^^^^^ only traits may use parentheses
+   |                  ^^^^^^^^^^^^^^
+   |                  |
+   |                  only `Fn` traits may use parentheses
+   |                  help: use angle brackets instead: `<isize, usize>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.rs b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.rs
index e795650447cc4..1af7f55674c6a 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.rs
@@ -5,8 +5,8 @@ struct Bar<A> {
 }
 
 fn foo(b: Box<Bar()>) {
-    //~^ ERROR parenthesized parameters may only be used with a trait
-    //~| ERROR the type placeholder `_` is not allowed within types on item signatures
+    //~^ ERROR parenthesized type parameters may only be used with a `Fn` trait
+    //~| ERROR wrong number of type arguments: expected 1, found 0
 }
 
 fn main() { }
diff --git a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.stderr b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.stderr
index d0267092030d8..b34237937ee1c 100644
--- a/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closure-sugar-used-on-struct.stderr
@@ -1,16 +1,16 @@
-error[E0214]: parenthesized parameters may only be used with a trait
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
   --> $DIR/unboxed-closure-sugar-used-on-struct.rs:7:18
    |
 LL | fn foo(b: Box<Bar()>) {
-   |                  ^^ only traits may use parentheses
+   |                  ^^ only `Fn` traits may use parentheses
 
-error[E0121]: the type placeholder `_` is not allowed within types on item signatures
+error[E0107]: wrong number of type arguments: expected 1, found 0
   --> $DIR/unboxed-closure-sugar-used-on-struct.rs:7:15
    |
 LL | fn foo(b: Box<Bar()>) {
-   |               ^^^^^ not allowed in type signatures
+   |               ^^^^^ expected 1 type argument
 
 error: aborting due to 2 previous errors
 
-Some errors occurred: E0121, E0214.
-For more information about an error, try `rustc --explain E0121`.
+Some errors occurred: E0107, E0214.
+For more information about an error, try `rustc --explain E0107`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.rs b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.rs
index 12626fe69cb14..a6e26614a6a50 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.rs
@@ -11,11 +11,13 @@ fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
 fn a() {
     let x = call_it(&square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn b() {
     let y = call_it_mut(&mut square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn c() {
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
index 29f276711c745..ca0298283661f 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-unsafe-extern-fn.stderr
@@ -11,8 +11,21 @@ note: required by `call_it`
 LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:12:13
+   |
+LL |     let x = call_it(&square, 22);
+   |             ^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+note: required by `call_it`
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:7:1
+   |
+LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0277]: expected a `std::ops::FnMut<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
-  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:17:13
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:18:13
    |
 LL |     let y = call_it_mut(&mut square, 22);
    |             ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
@@ -25,18 +38,31 @@ LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
-  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:22:13
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:18:13
+   |
+LL |     let y = call_it_mut(&mut square, 22);
+   |             ^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+note: required by `call_it_mut`
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:8:1
+   |
+LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
+  --> $DIR/unboxed-closures-unsafe-extern-fn.rs:24:13
    |
 LL |     let z = call_it_once(square, 22);
    |             ^^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> unsafe fn(&'r isize) -> isize {square}`
    |
-   = help: the trait `for<'r> std::ops::FnOnce<(&'r isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> unsafe fn(&'r isize) -> isize {square}`
 note: required by `call_it_once`
   --> $DIR/unboxed-closures-unsafe-extern-fn.rs:9:1
    |
 LL | fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.rs b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.rs
index 7c3152c87c461..dd3b1afc39f31 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.rs
@@ -11,11 +11,13 @@ fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
 fn a() {
     let x = call_it(&square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn b() {
     let y = call_it_mut(&mut square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn c() {
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
index e382457860579..0abc58aeebfe5 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-abi.stderr
@@ -11,8 +11,21 @@ note: required by `call_it`
 LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+  --> $DIR/unboxed-closures-wrong-abi.rs:12:13
+   |
+LL |     let x = call_it(&square, 22);
+   |             ^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+note: required by `call_it`
+  --> $DIR/unboxed-closures-wrong-abi.rs:7:1
+   |
+LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0277]: expected a `std::ops::FnMut<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
-  --> $DIR/unboxed-closures-wrong-abi.rs:17:13
+  --> $DIR/unboxed-closures-wrong-abi.rs:18:13
    |
 LL |     let y = call_it_mut(&mut square, 22);
    |             ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
@@ -25,18 +38,31 @@ LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
-  --> $DIR/unboxed-closures-wrong-abi.rs:22:13
+  --> $DIR/unboxed-closures-wrong-abi.rs:18:13
+   |
+LL |     let y = call_it_mut(&mut square, 22);
+   |             ^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+note: required by `call_it_mut`
+  --> $DIR/unboxed-closures-wrong-abi.rs:8:1
+   |
+LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+  --> $DIR/unboxed-closures-wrong-abi.rs:24:13
    |
 LL |     let z = call_it_once(square, 22);
    |             ^^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `for<'r> extern "C" fn(&'r isize) -> isize {square}`
    |
-   = help: the trait `for<'r> std::ops::FnOnce<(&'r isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `for<'r> extern "C" fn(&'r isize) -> isize {square}`
 note: required by `call_it_once`
   --> $DIR/unboxed-closures-wrong-abi.rs:9:1
    |
 LL | fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.rs b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.rs
index 61d46869cbbf2..c689d79266187 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.rs
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.rs
@@ -12,11 +12,13 @@ fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
 fn a() {
     let x = call_it(&square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn b() {
     let y = call_it_mut(&mut square, 22);
     //~^ ERROR E0277
+    //~| ERROR expected
 }
 
 fn c() {
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
index da511f091bf6a..19b87ad171a51 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-wrong-arg-type-extern-fn.stderr
@@ -11,8 +11,21 @@ note: required by `call_it`
 LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:13:13
+   |
+LL |     let x = call_it(&square, 22);
+   |             ^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+note: required by `call_it`
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:8:1
+   |
+LL | fn call_it<F:Fn(&isize)->isize>(_: &F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0277]: expected a `std::ops::FnMut<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
-  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:18:13
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:19:13
    |
 LL |     let y = call_it_mut(&mut square, 22);
    |             ^^^^^^^^^^^ expected an `FnMut<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
@@ -25,18 +38,31 @@ LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
-  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:23:13
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:19:13
+   |
+LL |     let y = call_it_mut(&mut square, 22);
+   |             ^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
+   |
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+note: required by `call_it_mut`
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:9:1
+   |
+LL | fn call_it_mut<F:FnMut(&isize)->isize>(_: &mut F, _: isize) -> isize { 0 }
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: expected a `std::ops::FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
+  --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:25:13
    |
 LL |     let z = call_it_once(square, 22);
    |             ^^^^^^^^^^^^ expected an `FnOnce<(&isize,)>` closure, found `unsafe fn(isize) -> isize {square}`
    |
-   = help: the trait `for<'r> std::ops::FnOnce<(&'r isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
+   = help: the trait `std::ops::FnOnce<(&isize,)>` is not implemented for `unsafe fn(isize) -> isize {square}`
 note: required by `call_it_once`
   --> $DIR/unboxed-closures-wrong-arg-type-extern-fn.rs:10:1
    |
 LL | fn call_it_once<F:FnOnce(&isize)->isize>(_: F, _: isize) -> isize { 0 }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/union/union-borrow-move-parent-sibling.nll.stderr b/src/test/ui/union/union-borrow-move-parent-sibling.nll.stderr
index 848c3d9bdb017..29d161fe150e7 100644
--- a/src/test/ui/union/union-borrow-move-parent-sibling.nll.stderr
+++ b/src/test/ui/union/union-borrow-move-parent-sibling.nll.stderr
@@ -13,12 +13,12 @@ LL |     use_borrow(a);
 error[E0382]: use of moved value: `u`
   --> $DIR/union-borrow-move-parent-sibling.rs:22:13
    |
+LL |     let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+   |         - move occurs because `u` has type `U`, which does not implement the `Copy` trait
 LL |     let a = u.x.0;
    |             ----- value moved here
 LL |     let b = u.y; //~ ERROR use of moved value: `u.y`
    |             ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `U`, which does not implement the `Copy` trait
 
 error[E0502]: cannot borrow `u` (via `u.y`) as immutable because it is also borrowed as mutable (via `u.x.0.0`)
   --> $DIR/union-borrow-move-parent-sibling.rs:28:13
@@ -35,12 +35,12 @@ LL |     use_borrow(a);
 error[E0382]: use of moved value: `u`
   --> $DIR/union-borrow-move-parent-sibling.rs:35:13
    |
+LL |     let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+   |         - move occurs because `u` has type `U`, which does not implement the `Copy` trait
 LL |     let a = (u.x.0).0;
    |             --------- value moved here
 LL |     let b = u.y; //~ ERROR use of moved value: `u.y`
    |             ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `U`, which does not implement the `Copy` trait
 
 error[E0502]: cannot borrow `u` (via `u.x`) as immutable because it is also borrowed as mutable (via `*u.y`)
   --> $DIR/union-borrow-move-parent-sibling.rs:41:13
@@ -57,12 +57,12 @@ LL |     use_borrow(a);
 error[E0382]: use of moved value: `u`
   --> $DIR/union-borrow-move-parent-sibling.rs:48:13
    |
+LL |     let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+   |         - move occurs because `u` has type `U`, which does not implement the `Copy` trait
 LL |     let a = *u.y;
    |             ---- value moved here
 LL |     let b = u.x; //~ ERROR use of moved value: `u.x`
    |             ^^^ value used here after move
-   |
-   = note: move occurs because `u` has type `U`, which does not implement the `Copy` trait
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/unop-move-semantics.nll.stderr b/src/test/ui/unop-move-semantics.nll.stderr
index 333a4734a4e5f..58953d55b1fba 100644
--- a/src/test/ui/unop-move-semantics.nll.stderr
+++ b/src/test/ui/unop-move-semantics.nll.stderr
@@ -1,13 +1,15 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/unop-move-semantics.rs:8:5
    |
+LL | fn move_then_borrow<T: Not<Output=T> + Clone>(x: T) {
+   |                     -                         - move occurs because `x` has type `T`, which does not implement the `Copy` trait
+   |                     |
+   |                     consider adding a `Copy` constraint to this type argument
 LL |     !x;
    |      - value moved here
 LL | 
 LL |     x.clone();  //~ ERROR: use of moved value
    |     ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `T`, which does not implement the `Copy` trait
 
 error[E0505]: cannot move out of `x` because it is borrowed
   --> $DIR/unop-move-semantics.rs:15:6
diff --git a/src/test/ui/unresolved/unresolved-extern-mod-suggestion.stderr b/src/test/ui/unresolved/unresolved-extern-mod-suggestion.stderr
index 012d3c3a7510f..e8679a3726d30 100644
--- a/src/test/ui/unresolved/unresolved-extern-mod-suggestion.stderr
+++ b/src/test/ui/unresolved/unresolved-extern-mod-suggestion.stderr
@@ -4,13 +4,12 @@ error[E0254]: the name `core` is defined multiple times
 LL | extern crate core;
    | ------------------ previous import of the extern crate `core` here
 LL | use core;
-   |     ^^^^ `core` reimported here
+   | ----^^^^-
+   | |   |
+   | |   `core` reimported here
+   | help: remove unnecessary import
    |
    = note: `core` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use core as other_core;
-   |     ^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/unsafe/ranged_ints2_const.stderr b/src/test/ui/unsafe/ranged_ints2_const.stderr
index 39a55190b17de..fb3841948f11f 100644
--- a/src/test/ui/unsafe/ranged_ints2_const.stderr
+++ b/src/test/ui/unsafe/ranged_ints2_const.stderr
@@ -1,14 +1,18 @@
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/ranged_ints2_const.rs:11:9
    |
 LL |     let y = &mut x.0; //~ ERROR references in const fn are unstable
    |         ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
-error: mutable references in const fn are unstable
+error[E0723]: mutable references in const fn are unstable (see issue #57563)
   --> $DIR/ranged_ints2_const.rs:18:9
    |
 LL |     let y = unsafe { &mut x.0 }; //~ ERROR mutable references in const fn are unstable
    |         ^
+   |
+   = help: add #![feature(const_fn)] to the crate attributes to enable
 
 error[E0133]: mutation of layout constrained field is unsafe and requires unsafe function or block
   --> $DIR/ranged_ints2_const.rs:11:13
@@ -20,4 +24,5 @@ LL |     let y = &mut x.0; //~ ERROR references in const fn are unstable
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0133`.
+Some errors occurred: E0133, E0723.
+For more information about an error, try `rustc --explain E0133`.
diff --git a/src/test/ui/unsized-locals/borrow-after-move.nll.stderr b/src/test/ui/unsized-locals/borrow-after-move.nll.stderr
index 18cba2047356a..0e6a6f6369a15 100644
--- a/src/test/ui/unsized-locals/borrow-after-move.nll.stderr
+++ b/src/test/ui/unsized-locals/borrow-after-move.nll.stderr
@@ -12,13 +12,13 @@ LL |         println!("{}", &x);
 error[E0382]: borrow of moved value: `y`
   --> $DIR/borrow-after-move.rs:22:24
    |
+LL |         let y = *x;
+   |             - move occurs because `y` has type `str`, which does not implement the `Copy` trait
 LL |         drop_unsized(y);
    |                      - value moved here
 ...
 LL |         println!("{}", &y);
    |                        ^^ value borrowed here after move
-   |
-   = note: move occurs because `y` has type `str`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/borrow-after-move.rs:30:24
@@ -34,13 +34,13 @@ LL |         println!("{}", &x);
 error[E0382]: borrow of moved value: `y`
   --> $DIR/borrow-after-move.rs:32:24
    |
+LL |         let y = *x;
+   |             - move occurs because `y` has type `str`, which does not implement the `Copy` trait
 LL |         y.foo();
    |         - value moved here
 ...
 LL |         println!("{}", &y);
    |                        ^^ value borrowed here after move
-   |
-   = note: move occurs because `y` has type `str`, which does not implement the `Copy` trait
 
 error[E0382]: borrow of moved value: `x`
   --> $DIR/borrow-after-move.rs:39:24
diff --git a/src/test/ui/unsized-locals/double-move.nll.stderr b/src/test/ui/unsized-locals/double-move.nll.stderr
index bbe6da70fb112..e40289af5ad3d 100644
--- a/src/test/ui/unsized-locals/double-move.nll.stderr
+++ b/src/test/ui/unsized-locals/double-move.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `y`
   --> $DIR/double-move.rs:20:22
    |
+LL |         let y = *x;
+   |             - move occurs because `y` has type `str`, which does not implement the `Copy` trait
 LL |         drop_unsized(y);
    |                      - value moved here
 LL |         drop_unsized(y); //~ERROR use of moved value
    |                      ^ value used here after move
-   |
-   = note: move occurs because `y` has type `str`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `x`
   --> $DIR/double-move.rs:26:22
@@ -21,22 +21,22 @@ LL |         drop_unsized(x); //~ERROR use of moved value
 error[E0382]: use of moved value: `*x`
   --> $DIR/double-move.rs:32:18
    |
+LL |         let x = "hello".to_owned().into_boxed_str();
+   |             - move occurs because `x` has type `std::boxed::Box<str>`, which does not implement the `Copy` trait
 LL |         drop_unsized(x);
    |                      - value moved here
 LL |         let _y = *x; //~ERROR use of moved value
    |                  ^^ value used here after move
-   |
-   = note: move occurs because `x` has type `std::boxed::Box<str>`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `y`
   --> $DIR/double-move.rs:39:9
    |
+LL |         let y = *x;
+   |             - move occurs because `y` has type `str`, which does not implement the `Copy` trait
 LL |         y.foo();
    |         - value moved here
 LL |         y.foo(); //~ERROR use of moved value
    |         ^ value used here after move
-   |
-   = note: move occurs because `y` has type `str`, which does not implement the `Copy` trait
 
 error[E0382]: use of moved value: `*x`
   --> $DIR/double-move.rs:45:9
diff --git a/src/test/ui/use-self-in-inner-fn.rs b/src/test/ui/use-self-in-inner-fn.rs
index cde96dc778bbe..eccb315feb1e2 100644
--- a/src/test/ui/use-self-in-inner-fn.rs
+++ b/src/test/ui/use-self-in-inner-fn.rs
@@ -4,8 +4,8 @@ impl A {
 //~^ NOTE `Self` type implicitly declared here, by this `impl`
     fn banana(&mut self) {
         fn peach(this: &Self) {
-        //~^ ERROR can't use type parameters from outer function
-        //~| NOTE use of type variable from outer function
+        //~^ ERROR can't use generic parameters from outer function
+        //~| NOTE use of generic parameter from outer function
         //~| NOTE use a type here instead
         }
     }
diff --git a/src/test/ui/use-self-in-inner-fn.stderr b/src/test/ui/use-self-in-inner-fn.stderr
index a613804b8038b..966093499241d 100644
--- a/src/test/ui/use-self-in-inner-fn.stderr
+++ b/src/test/ui/use-self-in-inner-fn.stderr
@@ -1,4 +1,4 @@
-error[E0401]: can't use type parameters from outer function
+error[E0401]: can't use generic parameters from outer function
   --> $DIR/use-self-in-inner-fn.rs:6:25
    |
 LL | impl A {
@@ -7,7 +7,7 @@ LL | impl A {
 LL |         fn peach(this: &Self) {
    |                         ^^^^
    |                         |
-   |                         use of type variable from outer function
+   |                         use of generic parameter from outer function
    |                         use a type here instead
 
 error: aborting due to previous error
diff --git a/src/test/ui/use/use-after-move-based-on-type.nll.stderr b/src/test/ui/use/use-after-move-based-on-type.nll.stderr
index 6f5b23b201333..8160ada9d62ea 100644
--- a/src/test/ui/use/use-after-move-based-on-type.nll.stderr
+++ b/src/test/ui/use/use-after-move-based-on-type.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `x`
   --> $DIR/use-after-move-based-on-type.rs:4:20
    |
+LL |     let x = "Hello!".to_string();
+   |         - move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 LL |     let _y = x;
    |              - value moved here
 LL |     println!("{}", x); //~ ERROR use of moved value
    |                    ^ value borrowed here after move
-   |
-   = note: move occurs because `x` has type `std::string::String`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/use/use-after-move-implicity-coerced-object.nll.stderr b/src/test/ui/use/use-after-move-implicity-coerced-object.nll.stderr
index 308134774efb3..e16bca380679f 100644
--- a/src/test/ui/use/use-after-move-implicity-coerced-object.nll.stderr
+++ b/src/test/ui/use/use-after-move-implicity-coerced-object.nll.stderr
@@ -1,12 +1,13 @@
 error[E0382]: borrow of moved value: `n`
   --> $DIR/use-after-move-implicity-coerced-object.rs:28:13
    |
+LL |     let n: Box<_> = box Number { n: 42 };
+   |         - move occurs because `n` has type `std::boxed::Box<Number>`, which does not implement the `Copy` trait
+LL |     let mut l: Box<_> = box List { list: Vec::new() };
 LL |     l.push(n);
    |            - value moved here
 LL |     let x = n.to_string();
    |             ^ value borrowed here after move
-   |
-   = note: move occurs because `n` has type `std::boxed::Box<Number>`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/use/use-after-move-self-based-on-type.nll.stderr b/src/test/ui/use/use-after-move-self-based-on-type.nll.stderr
index d7f7c3c30f6cd..4119741d805cd 100644
--- a/src/test/ui/use/use-after-move-self-based-on-type.nll.stderr
+++ b/src/test/ui/use/use-after-move-self-based-on-type.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `self`
   --> $DIR/use-after-move-self-based-on-type.rs:12:16
    |
+LL |     pub fn foo(self) -> isize {
+   |                ---- move occurs because `self` has type `S`, which does not implement the `Copy` trait
 LL |         self.bar();
    |         ---- value moved here
 LL |         return self.x;  //~ ERROR use of moved value: `self.x`
    |                ^^^^^^ value used here after move
-   |
-   = note: move occurs because `self` has type `S`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/use/use-after-move-self.nll.stderr b/src/test/ui/use/use-after-move-self.nll.stderr
index 3e11e94e993f5..e2ce3690cb904 100644
--- a/src/test/ui/use/use-after-move-self.nll.stderr
+++ b/src/test/ui/use/use-after-move-self.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: use of moved value: `self`
   --> $DIR/use-after-move-self.rs:10:16
    |
+LL |     pub fn foo(self) -> isize {
+   |                ---- move occurs because `self` has type `S`, which does not implement the `Copy` trait
 LL |         self.bar();
    |         ---- value moved here
 LL |         return *self.x;  //~ ERROR use of moved value: `*self.x`
    |                ^^^^^^^ value used here after move
-   |
-   = note: move occurs because `self` has type `S`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/use/use-mod.stderr b/src/test/ui/use/use-mod.stderr
index 9ab873b35989c..c23ab34eae678 100644
--- a/src/test/ui/use/use-mod.stderr
+++ b/src/test/ui/use/use-mod.stderr
@@ -20,13 +20,12 @@ LL |     self,
    |     ---- previous import of the module `bar` here
 ...
 LL |     self
-   |     ^^^^ `bar` reimported here
+   |     ^^^^
+   |     |
+   |     `bar` reimported here
+   |     help: remove unnecessary import
    |
    = note: `bar` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL |     self as other_bar
-   |
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/use/use-nested-groups-unused-imports.rs b/src/test/ui/use/use-nested-groups-unused-imports.rs
index 5bdc7b2c03f0f..5fe85954dc8e9 100644
--- a/src/test/ui/use/use-nested-groups-unused-imports.rs
+++ b/src/test/ui/use/use-nested-groups-unused-imports.rs
@@ -18,7 +18,7 @@ use foo::{Foo, bar::{baz::{}, foobar::*}, *};
 use foo::bar::baz::{*, *};
     //~^ ERROR unused import: `*`
 use foo::{};
-    //~^ ERROR unused import: `use foo::{};`
+    //~^ ERROR unused import: `foo::{}`
 
 fn main() {
     let _: Bar;
diff --git a/src/test/ui/use/use-nested-groups-unused-imports.stderr b/src/test/ui/use/use-nested-groups-unused-imports.stderr
index f60c7f5023798..c8df6cbc57dca 100644
--- a/src/test/ui/use/use-nested-groups-unused-imports.stderr
+++ b/src/test/ui/use/use-nested-groups-unused-imports.stderr
@@ -16,11 +16,11 @@ error: unused import: `*`
 LL | use foo::bar::baz::{*, *};
    |                        ^
 
-error: unused import: `use foo::{};`
-  --> $DIR/use-nested-groups-unused-imports.rs:20:1
+error: unused import: `foo::{}`
+  --> $DIR/use-nested-groups-unused-imports.rs:20:5
    |
 LL | use foo::{};
-   | ^^^^^^^^^^^^
+   |     ^^^^^^^
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/use/use-paths-as-items.stderr b/src/test/ui/use/use-paths-as-items.stderr
index 5bcdf937d5698..00f468cdf316b 100644
--- a/src/test/ui/use/use-paths-as-items.stderr
+++ b/src/test/ui/use/use-paths-as-items.stderr
@@ -4,13 +4,12 @@ error[E0252]: the name `mem` is defined multiple times
 LL | use std::{mem, ptr};
    |           --- previous import of the module `mem` here
 LL | use std::mem; //~ ERROR the name `mem` is defined multiple times
-   |     ^^^^^^^^ `mem` reimported here
+   | ----^^^^^^^^-
+   | |   |
+   | |   `mem` reimported here
+   | help: remove unnecessary import
    |
    = note: `mem` must be defined only once in the type namespace of this module
-help: you can use `as` to change the binding name of the import
-   |
-LL | use std::mem as other_mem; //~ ERROR the name `mem` is defined multiple times
-   |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/utf8_idents.rs b/src/test/ui/utf8_idents.rs
index e601c6e455544..f59d5502aae30 100644
--- a/src/test/ui/utf8_idents.rs
+++ b/src/test/ui/utf8_idents.rs
@@ -1,9 +1,7 @@
-//
-
 fn foo<
     'β, //~ ERROR non-ascii idents are not fully supported
     γ  //~ ERROR non-ascii idents are not fully supported
-       //~^ WARN type parameter `γ` should have a camel case name
+       //~^ WARN type parameter `γ` should have an upper camel case name
 >() {}
 
 struct X {
diff --git a/src/test/ui/utf8_idents.stderr b/src/test/ui/utf8_idents.stderr
index 268dd99d06031..52fb607af5b25 100644
--- a/src/test/ui/utf8_idents.stderr
+++ b/src/test/ui/utf8_idents.stderr
@@ -1,5 +1,5 @@
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:4:5
+  --> $DIR/utf8_idents.rs:2:5
    |
 LL |     'β, //~ ERROR non-ascii idents are not fully supported
    |     ^^
@@ -7,7 +7,7 @@ LL |     'β, //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:5:5
+  --> $DIR/utf8_idents.rs:3:5
    |
 LL |     γ  //~ ERROR non-ascii idents are not fully supported
    |     ^
@@ -15,7 +15,7 @@ LL |     γ  //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:10:5
+  --> $DIR/utf8_idents.rs:8:5
    |
 LL |     δ: usize //~ ERROR non-ascii idents are not fully supported
    |     ^
@@ -23,18 +23,18 @@ LL |     δ: usize //~ ERROR non-ascii idents are not fully supported
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
 error[E0658]: non-ascii idents are not fully supported. (see issue #55467)
-  --> $DIR/utf8_idents.rs:14:9
+  --> $DIR/utf8_idents.rs:12:9
    |
 LL |     let α = 0.00001f64; //~ ERROR non-ascii idents are not fully supported
    |         ^
    |
    = help: add #![feature(non_ascii_idents)] to the crate attributes to enable
 
-warning: type parameter `γ` should have a camel case name
-  --> $DIR/utf8_idents.rs:5:5
+warning: type parameter `γ` should have an upper camel case name
+  --> $DIR/utf8_idents.rs:3:5
    |
 LL |     γ  //~ ERROR non-ascii idents are not fully supported
-   |     ^ help: convert the identifier to camel case: `Γ`
+   |     ^ help: convert the identifier to upper camel case: `Γ`
    |
    = note: #[warn(non_camel_case_types)] on by default
 
diff --git a/src/test/ui/vec/vec-mut-iter-borrow.nll.stderr b/src/test/ui/vec/vec-mut-iter-borrow.nll.stderr
index 73cddd8d680a6..c77be26f01938 100644
--- a/src/test/ui/vec/vec-mut-iter-borrow.nll.stderr
+++ b/src/test/ui/vec/vec-mut-iter-borrow.nll.stderr
@@ -5,7 +5,7 @@ LL |     for x in &mut xs {
    |              -------
    |              |
    |              first mutable borrow occurs here
-   |              first borrow used here, in later iteration of loop
+   |              first borrow later used here
 LL |         xs.push(1) //~ ERROR cannot borrow `xs`
    |         ^^ second mutable borrow occurs here
 
diff --git a/src/test/ui/walk-struct-literal-with.nll.stderr b/src/test/ui/walk-struct-literal-with.nll.stderr
index 22ad3b1e2f2e7..2263747607b9c 100644
--- a/src/test/ui/walk-struct-literal-with.nll.stderr
+++ b/src/test/ui/walk-struct-literal-with.nll.stderr
@@ -1,12 +1,12 @@
 error[E0382]: borrow of moved value: `start`
   --> $DIR/walk-struct-literal-with.rs:16:20
    |
+LL |     let start = Mine{test:"Foo".to_string(), other_val:0};
+   |         ----- move occurs because `start` has type `Mine`, which does not implement the `Copy` trait
 LL |     let end = Mine{other_val:1, ..start.make_string_bar()};
    |                                   ----- value moved here
 LL |     println!("{}", start.test); //~ ERROR use of moved value: `start.test`
    |                    ^^^^^^^^^^ value borrowed here after move
-   |
-   = note: move occurs because `start` has type `Mine`, which does not implement the `Copy` trait
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/where-clauses/where-for-self-2.rs b/src/test/ui/where-clauses/where-for-self-2.rs
index 0ce38e69f6b0f..31174fd4cf163 100644
--- a/src/test/ui/where-clauses/where-for-self-2.rs
+++ b/src/test/ui/where-clauses/where-for-self-2.rs
@@ -18,5 +18,5 @@ fn foo<T>(x: &T)
 {}
 
 fn main() {
-    foo(&X); //~ ERROR implementation of `Bar` is not general enough
+    foo(&X); //~ ERROR trait bound
 }
diff --git a/src/test/ui/where-clauses/where-for-self-2.stderr b/src/test/ui/where-clauses/where-for-self-2.stderr
index afc80bf4d8ee6..bbcb61a856d8d 100644
--- a/src/test/ui/where-clauses/where-for-self-2.stderr
+++ b/src/test/ui/where-clauses/where-for-self-2.stderr
@@ -1,12 +1,19 @@
-error: implementation of `Bar` is not general enough
+error[E0277]: the trait bound `for<'a> &'a _: Bar` is not satisfied
   --> $DIR/where-for-self-2.rs:21:5
    |
-LL |     foo(&X); //~ ERROR implementation of `Bar` is not general enough
-   |     ^^^
+LL |     foo(&X); //~ ERROR trait bound
+   |     ^^^ the trait `for<'a> Bar` is not implemented for `&'a _`
    |
-   = note: Due to a where-clause on `foo`,
-   = note: `&'0 _` must implement `Bar` for any lifetime `'0`
-   = note: but `&'1 u32` only implements `Bar` for the lifetime `'1`
+   = help: the following implementations were found:
+             <&'static u32 as Bar>
+note: required by `foo`
+  --> $DIR/where-for-self-2.rs:16:1
+   |
+LL | / fn foo<T>(x: &T)
+LL | |     where for<'a> &'a T: Bar
+LL | | {}
+   | |__^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/wrong-ret-type.stderr b/src/test/ui/wrong-ret-type.stderr
index 221806f731f60..cf59f42683d72 100644
--- a/src/test/ui/wrong-ret-type.stderr
+++ b/src/test/ui/wrong-ret-type.stderr
@@ -2,7 +2,9 @@ error[E0308]: mismatched types
   --> $DIR/wrong-ret-type.rs:2:49
    |
 LL | fn mk_int() -> usize { let i: isize = 3; return i; }
-   |                                                 ^ expected usize, found isize
+   |                -----                            ^ expected usize, found isize
+   |                |
+   |                expected `usize` because of return type
 
 error: aborting due to previous error
 
diff --git a/src/tools/build-manifest/Cargo.toml b/src/tools/build-manifest/Cargo.toml
index 844b7aad72fde..93d0f61e1d9f0 100644
--- a/src/tools/build-manifest/Cargo.toml
+++ b/src/tools/build-manifest/Cargo.toml
@@ -2,8 +2,9 @@
 name = "build-manifest"
 version = "0.1.0"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
+edition = "2018"
 
 [dependencies]
 toml = "0.4"
-serde = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 serde_derive = "1.0"
diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
index 8c1baa55bcdca..8d87c404d0b28 100644
--- a/src/tools/build-manifest/src/main.rs
+++ b/src/tools/build-manifest/src/main.rs
@@ -1,6 +1,7 @@
-extern crate toml;
-#[macro_use]
-extern crate serde_derive;
+#![deny(rust_2018_idioms)]
+
+use toml;
+use serde::Serialize;
 
 use std::collections::BTreeMap;
 use std::env;
@@ -78,11 +79,14 @@ static TARGETS: &'static [&'static str] = &[
     "mips64el-unknown-linux-gnuabi64",
     "mipsel-unknown-linux-gnu",
     "mipsel-unknown-linux-musl",
+    "nvptx64-nvidia-cuda",
     "powerpc-unknown-linux-gnu",
     "powerpc64-unknown-linux-gnu",
     "powerpc64le-unknown-linux-gnu",
     "riscv32imc-unknown-none-elf",
     "riscv32imac-unknown-none-elf",
+    "riscv64imac-unknown-none-elf",
+    "riscv64gc-unknown-none-elf",
     "s390x-unknown-linux-gnu",
     "sparc64-unknown-linux-gnu",
     "sparcv9-sun-solaris",
@@ -95,6 +99,7 @@ static TARGETS: &'static [&'static str] = &[
     "wasm32-unknown-unknown",
     "x86_64-apple-darwin",
     "x86_64-apple-ios",
+    "x86_64-fortanix-unknown-sgx",
     "x86_64-fuchsia",
     "x86_64-linux-android",
     "x86_64-pc-windows-gnu",
@@ -467,7 +472,7 @@ impl Builder {
         }
         manifest.pkg.insert("rust".to_string(), pkg);
 
-        return manifest;
+        manifest
     }
 
     fn profile(&mut self,
diff --git a/src/tools/cargo b/src/tools/cargo
index 2b4a5f1f0bb6e..b33ce7fc90929 160000
--- a/src/tools/cargo
+++ b/src/tools/cargo
@@ -1 +1 @@
-Subproject commit 2b4a5f1f0bb6e13759e88ea9512527b0beba154f
+Subproject commit b33ce7fc9092962b0657b4c25354984b5e5c47e4
diff --git a/src/tools/cargotest/Cargo.toml b/src/tools/cargotest/Cargo.toml
index f4163a6f1170a..3811fee39368f 100644
--- a/src/tools/cargotest/Cargo.toml
+++ b/src/tools/cargotest/Cargo.toml
@@ -2,6 +2,7 @@
 name = "cargotest2"
 version = "0.1.0"
 authors = ["Brian Anderson <banderson@mozilla.com>"]
+edition = "2018"
 
 [[bin]]
 name = "cargotest"
diff --git a/src/tools/cargotest/main.rs b/src/tools/cargotest/main.rs
index 120f238eb45c5..7f3c159075b97 100644
--- a/src/tools/cargotest/main.rs
+++ b/src/tools/cargotest/main.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 use std::env;
 use std::process::Command;
 use std::path::{Path, PathBuf};
diff --git a/src/tools/clang b/src/tools/clang
deleted file mode 160000
index 032312dd0140a..0000000000000
--- a/src/tools/clang
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 032312dd0140a7074c9b89d305fe44eb0e44e407
diff --git a/src/tools/clippy b/src/tools/clippy
index 1b89724b4889a..d61b25419bec5 160000
--- a/src/tools/clippy
+++ b/src/tools/clippy
@@ -1 +1 @@
-Subproject commit 1b89724b4889aef631b40d52c0943bdc28e04d1d
+Subproject commit d61b25419bec5a3e839fdb16f720cfb12e52ddf1
diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index edf4aeab1c70f..00e1a53473cda 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "compiletest"
 version = "0.0.0"
+edition = "2018"
 
 [dependencies]
 diff = "0.1.10"
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 98bc6e8ac0084..6b3117a1f74f4 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -5,7 +5,7 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
 use test::ColorConfig;
-use util::PathBufExt;
+use crate::util::PathBufExt;
 
 #[derive(Clone, Copy, PartialEq, Debug)]
 pub enum Mode {
@@ -66,7 +66,7 @@ impl FromStr for Mode {
 }
 
 impl fmt::Display for Mode {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let s = match *self {
             CompileFail => "compile-fail",
             RunFail => "run-fail",
@@ -113,37 +113,41 @@ impl CompareMode {
 
 #[derive(Clone)]
 pub struct Config {
-    /// Whether to overwrite stderr/stdout files instead of complaining about changes in output
+    /// `true` to to overwrite stderr/stdout files instead of complaining about changes in output.
     pub bless: bool,
 
-    /// The library paths required for running the compiler
+    /// The library paths required for running the compiler.
     pub compile_lib_path: PathBuf,
 
-    /// The library paths required for running compiled programs
+    /// The library paths required for running compiled programs.
     pub run_lib_path: PathBuf,
 
-    /// The rustc executable
+    /// The rustc executable.
     pub rustc_path: PathBuf,
 
-    /// The rustdoc executable
+    /// The rustdoc executable.
     pub rustdoc_path: Option<PathBuf>,
 
-    /// The python executable to use for LLDB
+    /// The Python executable to use for LLDB.
     pub lldb_python: String,
 
-    /// The python executable to use for htmldocck
+    /// The Python executable to use for htmldocck.
     pub docck_python: String,
 
-    /// The llvm FileCheck binary path
+    /// The LLVM `FileCheck` binary path.
     pub llvm_filecheck: Option<PathBuf>,
 
-    /// The valgrind path
+    /// The valgrind path.
     pub valgrind_path: Option<String>,
 
     /// Whether to fail if we can't run run-pass-valgrind tests under valgrind
     /// (or, alternatively, to silently run them like regular run-pass tests).
     pub force_valgrind: bool,
 
+    /// The path to the Clang executable to run Clang-based tests with. If
+    /// `None` then these tests will be ignored.
+    pub run_clang_based_tests_with: Option<String>,
+
     /// The directory containing the tests to run
     pub src_base: PathBuf,
 
@@ -301,7 +305,7 @@ pub fn output_testname_unique(
 }
 
 /// Absolute path to the directory where all output for the given
-/// test/revision should reside.  Example:
+/// test/revision should reside. Example:
 ///   /path/to/build/host-triple/test/ui/relative/testname.revision.mode/
 pub fn output_base_dir(config: &Config, testpaths: &TestPaths, revision: Option<&str>) -> PathBuf {
     output_relative_path(config, &testpaths.relative_dir)
@@ -309,7 +313,7 @@ pub fn output_base_dir(config: &Config, testpaths: &TestPaths, revision: Option<
 }
 
 /// Absolute path to the base filename used as output for the given
-/// test/revision.  Example:
+/// test/revision. Example:
 ///   /path/to/build/host-triple/test/ui/relative/testname.revision.mode/testname
 pub fn output_base_name(config: &Config, testpaths: &TestPaths, revision: Option<&str>) -> PathBuf {
     output_base_dir(config, testpaths, revision).join(testpaths.file.file_stem().unwrap())
diff --git a/src/tools/compiletest/src/errors.rs b/src/tools/compiletest/src/errors.rs
index fd3f002fb6682..0329fb0db1422 100644
--- a/src/tools/compiletest/src/errors.rs
+++ b/src/tools/compiletest/src/errors.rs
@@ -33,7 +33,7 @@ impl FromStr for ErrorKind {
 }
 
 impl fmt::Display for ErrorKind {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             ErrorKind::Help => write!(f, "help message"),
             ErrorKind::Error => write!(f, "error"),
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index 5eb1f5ec5ffda..c2c4a6b69cca5 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -4,15 +4,15 @@ use std::io::prelude::*;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
 
-use common::{self, CompareMode, Config, Mode};
-use util;
+use crate::common::{self, CompareMode, Config, Mode};
+use crate::util;
 
-use extract_gdb_version;
+use crate::extract_gdb_version;
 
 /// Whether to ignore the test.
 #[derive(Clone, Copy, PartialEq, Debug)]
 pub enum Ignore {
-    /// Run it.
+    /// Runs it.
     Run,
     /// Ignore it totally.
     Ignore,
@@ -111,6 +111,11 @@ impl EarlyProps {
                 if ignore_llvm(config, ln) {
                     props.ignore = Ignore::Ignore;
                 }
+
+                if config.run_clang_based_tests_with.is_none() &&
+                   config.parse_needs_matching_clang(ln) {
+                    props.ignore = Ignore::Ignore;
+                }
             }
 
             if (config.mode == common::DebugInfoGdb || config.mode == common::DebugInfoBoth) &&
@@ -384,7 +389,7 @@ impl TestProps {
         props
     }
 
-    /// Load properties from `testfile` into `props`. If a property is
+    /// Loads properties from `testfile` into `props`. If a property is
     /// tied to a particular revision `foo` (indicated by writing
     /// `//[foo]`), then the property is ignored unless `cfg` is
     /// `Some("foo")`.
@@ -542,6 +547,8 @@ fn iter_header(testfile: &Path, cfg: Option<&str>, it: &mut dyn FnMut(&str)) {
         "#"
     };
 
+    // FIXME: would be nice to allow some whitespace between comment and brace :)
+    // It took me like 2 days to debug why compile-flags weren’t taken into account for my test :)
     let comment_with_brace = comment.to_string() + "[";
 
     let rdr = BufReader::new(File::open(testfile).unwrap());
@@ -705,6 +712,10 @@ impl Config {
         }
     }
 
+    fn parse_needs_matching_clang(&self, line: &str) -> bool {
+        self.parse_name_directive(line, "needs-matching-clang")
+    }
+
     /// Parses a name-value directive which contains config-specific information, e.g., `ignore-x86`
     /// or `normalize-stderr-32bit`.
     fn parse_cfg_name_directive(&self, line: &str, prefix: &str) -> ParsedNameDirective {
diff --git a/src/tools/compiletest/src/json.rs b/src/tools/compiletest/src/json.rs
index 106aa67157a42..12aae303f29aa 100644
--- a/src/tools/compiletest/src/json.rs
+++ b/src/tools/compiletest/src/json.rs
@@ -1,5 +1,5 @@
-use errors::{Error, ErrorKind};
-use runtest::ProcRes;
+use crate::errors::{Error, ErrorKind};
+use crate::runtest::ProcRes;
 use serde_json;
 use std::path::Path;
 use std::str::FromStr;
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index 2e5feca54151c..86cdadade108f 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -1,29 +1,21 @@
 #![crate_name = "compiletest"]
 #![feature(test)]
-#![deny(warnings)]
+#![deny(warnings, rust_2018_idioms)]
 
-extern crate diff;
-extern crate env_logger;
-extern crate filetime;
-extern crate getopts;
 #[cfg(unix)]
 extern crate libc;
 #[macro_use]
 extern crate log;
-extern crate regex;
 #[macro_use]
 extern crate lazy_static;
 #[macro_use]
 extern crate serde_derive;
-extern crate serde_json;
 extern crate test;
-extern crate rustfix;
-extern crate walkdir;
 
-use common::CompareMode;
-use common::{expected_output_path, output_base_dir, output_relative_path, UI_EXTENSIONS};
-use common::{Config, TestPaths};
-use common::{DebugInfoBoth, DebugInfoGdb, DebugInfoLldb, Mode, Pretty};
+use crate::common::CompareMode;
+use crate::common::{expected_output_path, output_base_dir, output_relative_path, UI_EXTENSIONS};
+use crate::common::{Config, TestPaths};
+use crate::common::{DebugInfoBoth, DebugInfoGdb, DebugInfoLldb, Mode, Pretty};
 use filetime::FileTime;
 use getopts::Options;
 use std::env;
@@ -33,8 +25,10 @@ use std::io::{self, ErrorKind};
 use std::path::{Path, PathBuf};
 use std::process::Command;
 use test::ColorConfig;
-use util::logv;
+use crate::util::logv;
 use walkdir::WalkDir;
+use env_logger;
+use getopts;
 
 use self::header::{EarlyProps, Ignore};
 
@@ -108,6 +102,12 @@ pub fn parse_config(args: Vec<String>) -> Config {
             "force-valgrind",
             "fail if Valgrind tests cannot be run under Valgrind",
         )
+        .optopt(
+            "",
+            "run-clang-based-tests-with",
+            "path to Clang executable",
+            "PATH",
+        )
         .optopt(
             "",
             "llvm-filecheck",
@@ -298,6 +298,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         docck_python: matches.opt_str("docck-python").unwrap(),
         valgrind_path: matches.opt_str("valgrind-path"),
         force_valgrind: matches.opt_present("force-valgrind"),
+        run_clang_based_tests_with: matches.opt_str("run-clang-based-tests-with"),
         llvm_filecheck: matches.opt_str("llvm-filecheck").map(|s| PathBuf::from(&s)),
         src_base,
         build_base: opt_path(matches, "build-base"),
@@ -669,15 +670,6 @@ fn stamp(config: &Config, testpaths: &TestPaths, revision: Option<&str>) -> Path
     output_base_dir(config, testpaths, revision).join("stamp")
 }
 
-/// Return an iterator over timestamps of files in the directory at `path`.
-fn collect_timestamps(path: &PathBuf) -> impl Iterator<Item=FileTime> {
-    WalkDir::new(path)
-        .into_iter()
-        .map(|entry| entry.unwrap())
-        .filter(|entry| entry.file_type().is_file())
-        .map(|entry| mtime(entry.path()))
-}
-
 fn up_to_date(
     config: &Config,
     testpaths: &TestPaths,
@@ -700,13 +692,15 @@ fn up_to_date(
     let rust_src_dir = config
         .find_rust_src_root()
         .expect("Could not find Rust source root");
-    let stamp = mtime(&stamp_name);
-    let mut inputs = vec![mtime(&testpaths.file), mtime(&config.rustc_path)];
+    let stamp = Stamp::from_path(&stamp_name);
+    let mut inputs = vec![Stamp::from_path(&testpaths.file), Stamp::from_path(&config.rustc_path)];
     inputs.extend(
         props
             .aux
             .iter()
-            .map(|aux| mtime(&testpaths.file.parent().unwrap().join("auxiliary").join(aux))),
+            .map(|aux| {
+                Stamp::from_path(&testpaths.file.parent().unwrap().join("auxiliary").join(aux))
+            }),
     );
     // Relevant pretty printer files
     let pretty_printer_files = [
@@ -717,24 +711,47 @@ fn up_to_date(
         "src/etc/lldb_rust_formatters.py",
     ];
     inputs.extend(pretty_printer_files.iter().map(|pretty_printer_file| {
-        mtime(&rust_src_dir.join(pretty_printer_file))
+        Stamp::from_path(&rust_src_dir.join(pretty_printer_file))
     }));
-    inputs.extend(collect_timestamps(&config.run_lib_path));
+    inputs.extend(Stamp::from_dir(&config.run_lib_path));
     if let Some(ref rustdoc_path) = config.rustdoc_path {
-        inputs.push(mtime(&rustdoc_path));
-        inputs.push(mtime(&rust_src_dir.join("src/etc/htmldocck.py")));
+        inputs.push(Stamp::from_path(&rustdoc_path));
+        inputs.push(Stamp::from_path(&rust_src_dir.join("src/etc/htmldocck.py")));
     }
 
     // UI test files.
     inputs.extend(UI_EXTENSIONS.iter().map(|extension| {
         let path = &expected_output_path(testpaths, revision, &config.compare_mode, extension);
-        mtime(path)
+        Stamp::from_path(path)
     }));
 
     // Compiletest itself.
-    inputs.extend(collect_timestamps(&rust_src_dir.join("src/tools/compiletest/")));
+    inputs.extend(Stamp::from_dir(&rust_src_dir.join("src/tools/compiletest/")));
 
-    inputs.iter().any(|input| *input > stamp)
+    inputs.iter().any(|input| input > &stamp)
+}
+
+#[derive(Debug, PartialEq, PartialOrd, Ord, Eq)]
+struct Stamp {
+    time: FileTime,
+    file: PathBuf,
+}
+
+impl Stamp {
+    fn from_path(p: &Path) -> Self {
+        Stamp {
+            time: mtime(&p),
+            file: p.into(),
+        }
+    }
+
+    fn from_dir(path: &Path) -> impl Iterator<Item=Stamp> {
+        WalkDir::new(path)
+            .into_iter()
+            .map(|entry| entry.unwrap())
+            .filter(|entry| entry.file_type().is_file())
+            .map(|entry| Stamp::from_path(entry.path()))
+    }
 }
 
 fn mtime(path: &Path) -> FileTime {
@@ -791,7 +808,7 @@ fn make_test_closure(
     }))
 }
 
-/// Returns true if the given target is an Android target for the
+/// Returns `true` if the given target is an Android target for the
 /// purposes of GDB testing.
 fn is_android_gdb_target(target: &String) -> bool {
     match &target[..] {
diff --git a/src/tools/compiletest/src/read2.rs b/src/tools/compiletest/src/read2.rs
index 5a4caddcdd319..6dfd8e97c636d 100644
--- a/src/tools/compiletest/src/read2.rs
+++ b/src/tools/compiletest/src/read2.rs
@@ -100,18 +100,15 @@ mod imp {
 
 #[cfg(windows)]
 mod imp {
-    extern crate miow;
-    extern crate winapi;
-
     use std::io;
     use std::os::windows::prelude::*;
     use std::process::{ChildStderr, ChildStdout};
     use std::slice;
 
-    use self::miow::iocp::{CompletionPort, CompletionStatus};
-    use self::miow::pipe::NamedPipe;
-    use self::miow::Overlapped;
-    use self::winapi::shared::winerror::ERROR_BROKEN_PIPE;
+    use miow::iocp::{CompletionPort, CompletionStatus};
+    use miow::pipe::NamedPipe;
+    use miow::Overlapped;
+    use winapi::shared::winerror::ERROR_BROKEN_PIPE;
 
     struct Pipe<'a> {
         dst: &'a mut Vec<u8>,
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 400c205d44b20..bac41a7c57904 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1,18 +1,18 @@
-use common::CompareMode;
-use common::{expected_output_path, UI_EXTENSIONS, UI_FIXED, UI_STDERR, UI_STDOUT};
-use common::{output_base_dir, output_base_name, output_testname_unique};
-use common::{Codegen, CodegenUnits, DebugInfoBoth, DebugInfoGdb, DebugInfoLldb, Rustdoc};
-use common::{CompileFail, Pretty, RunFail, RunPass, RunPassValgrind};
-use common::{Config, TestPaths};
-use common::{Incremental, MirOpt, RunMake, Ui};
+use crate::common::CompareMode;
+use crate::common::{expected_output_path, UI_EXTENSIONS, UI_FIXED, UI_STDERR, UI_STDOUT};
+use crate::common::{output_base_dir, output_base_name, output_testname_unique};
+use crate::common::{Codegen, CodegenUnits, DebugInfoBoth, DebugInfoGdb, DebugInfoLldb, Rustdoc};
+use crate::common::{CompileFail, Pretty, RunFail, RunPass, RunPassValgrind};
+use crate::common::{Config, TestPaths};
+use crate::common::{Incremental, MirOpt, RunMake, Ui};
 use diff;
-use errors::{self, Error, ErrorKind};
+use crate::errors::{self, Error, ErrorKind};
 use filetime::FileTime;
-use header::TestProps;
-use json;
+use crate::header::TestProps;
+use crate::json;
 use regex::Regex;
 use rustfix::{apply_suggestions, get_suggestions_from_json, Filter};
-use util::{logv, PathBufExt};
+use crate::util::{logv, PathBufExt};
 
 use std::collections::hash_map::DefaultHasher;
 use std::collections::{HashMap, HashSet, VecDeque};
@@ -27,8 +27,8 @@ use std::path::{Path, PathBuf};
 use std::process::{Child, Command, ExitStatus, Output, Stdio};
 use std::str;
 
-use extract_gdb_version;
-use is_android_gdb_target;
+use crate::extract_gdb_version;
+use crate::is_android_gdb_target;
 
 #[cfg(windows)]
 fn disable_error_reporting<F: FnOnce() -> R, R>(f: F) -> R {
@@ -552,9 +552,10 @@ impl<'test> TestCx<'test> {
             .args(&["--target", &self.config.target])
             .arg("-L")
             .arg(&aux_dir)
-            .args(self.split_maybe_args(&self.config.target_rustcflags))
             .args(&self.props.compile_flags)
             .envs(self.props.exec_env.clone());
+        self.maybe_add_external_args(&mut rustc,
+                                     self.split_maybe_args(&self.config.target_rustcflags));
 
         let src = match read_from {
             ReadFrom::Stdin(src) => Some(src),
@@ -587,6 +588,15 @@ impl<'test> TestCx<'test> {
         }
     }
 
+    fn set_revision_flags(&self, cmd: &mut Command) {
+        if let Some(revision) = self.revision {
+            // Normalize revisions to be lowercase and replace `-`s with `_`s.
+            // Otherwise the `--cfg` flag is not valid.
+            let normalized_revision = revision.to_lowercase().replace("-", "_");
+            cmd.args(&["--cfg", &normalized_revision]);
+        }
+    }
+
     fn typecheck_source(&self, src: String) -> ProcRes {
         let mut rustc = Command::new(&self.config.rustc_path);
 
@@ -612,12 +622,9 @@ impl<'test> TestCx<'test> {
             .arg(&self.config.build_base)
             .arg("-L")
             .arg(aux_dir);
-
-        if let Some(revision) = self.revision {
-            rustc.args(&["--cfg", revision]);
-        }
-
-        rustc.args(self.split_maybe_args(&self.config.target_rustcflags));
+        self.set_revision_flags(&mut rustc);
+        self.maybe_add_external_args(&mut rustc,
+                                     self.split_maybe_args(&self.config.target_rustcflags));
         rustc.args(&self.props.compile_flags);
 
         self.compose_and_run_compiler(rustc, Some(src))
@@ -1119,6 +1126,35 @@ impl<'test> TestCx<'test> {
         Some(new_options.join(" "))
     }
 
+    fn maybe_add_external_args(&self, cmd: &mut Command, args: Vec<String>) {
+        // Filter out the arguments that should not be added by runtest here.
+        //
+        // Notable use-cases are: do not add our optimisation flag if
+        // `compile-flags: -Copt-level=x` and similar for debug-info level as well.
+        const OPT_FLAGS: &[&str] = &["-O", "-Copt-level=", /*-C<space>*/"opt-level="];
+        const DEBUG_FLAGS: &[&str] = &["-g", "-Cdebuginfo=", /*-C<space>*/"debuginfo="];
+
+        // FIXME: ideally we would "just" check the `cmd` itself, but it does not allow inspecting
+        // its arguments. They need to be collected separately. For now I cannot be bothered to
+        // implement this the "right" way.
+        let have_opt_flag = self.props.compile_flags.iter().any(|arg| {
+            OPT_FLAGS.iter().any(|f| arg.starts_with(f))
+        });
+        let have_debug_flag = self.props.compile_flags.iter().any(|arg| {
+            DEBUG_FLAGS.iter().any(|f| arg.starts_with(f))
+        });
+
+        for arg in args {
+            if OPT_FLAGS.iter().any(|f| arg.starts_with(f)) && have_opt_flag {
+                continue;
+            }
+            if DEBUG_FLAGS.iter().any(|f| arg.starts_with(f)) && have_debug_flag {
+                continue;
+            }
+            cmd.arg(arg);
+        }
+    }
+
     fn check_debugger_output(&self, debugger_run_result: &ProcRes, check_lines: &[String]) {
         let num_check_lines = check_lines.len();
 
@@ -1343,7 +1379,7 @@ impl<'test> TestCx<'test> {
         }
     }
 
-    /// Returns true if we should report an error about `actual_error`,
+    /// Returns `true` if we should report an error about `actual_error`,
     /// which did not match any of the expected error. We always require
     /// errors/warnings to be explicitly listed, but only require
     /// helps/notes if there are explicit helps/notes given.
@@ -1691,6 +1727,9 @@ impl<'test> TestCx<'test> {
         // FIXME Why is -L here?
         rustc.arg(input_file); //.arg("-L").arg(&self.config.build_base);
 
+        // Use a single thread for efficiency and a deterministic error message order
+        rustc.arg("-Zthreads=1");
+
         // Optionally prevent default --target if specified in test compile-flags.
         let custom_target = self
             .props
@@ -1707,10 +1746,7 @@ impl<'test> TestCx<'test> {
 
             rustc.arg(&format!("--target={}", target));
         }
-
-        if let Some(revision) = self.revision {
-            rustc.args(&["--cfg", revision]);
-        }
+        self.set_revision_flags(&mut rustc);
 
         if !is_rustdoc {
             if let Some(ref incremental_dir) = self.props.incremental_dir {
@@ -1810,9 +1846,11 @@ impl<'test> TestCx<'test> {
         }
 
         if self.props.force_host {
-            rustc.args(self.split_maybe_args(&self.config.host_rustcflags));
+            self.maybe_add_external_args(&mut rustc,
+                                         self.split_maybe_args(&self.config.host_rustcflags));
         } else {
-            rustc.args(self.split_maybe_args(&self.config.target_rustcflags));
+            self.maybe_add_external_args(&mut rustc,
+                                         self.split_maybe_args(&self.config.target_rustcflags));
             if !is_rustdoc {
                 if let Some(ref linker) = self.config.linker {
                     rustc.arg(format!("-Clinker={}", linker));
@@ -1899,7 +1937,7 @@ impl<'test> TestCx<'test> {
     }
 
     fn make_cmdline(&self, command: &Command, libpath: &str) -> String {
-        use util;
+        use crate::util;
 
         // Linux and mac don't require adjusting the library search path
         if cfg!(unix) {
@@ -1936,14 +1974,14 @@ impl<'test> TestCx<'test> {
         fs::write(&outfile, out).unwrap();
     }
 
-    /// Create a filename for output with the given extension.  Example:
-    ///   /.../testname.revision.mode/testname.extension
+    /// Creates a filename for output with the given extension.
+    /// E.g., `/.../testname.revision.mode/testname.extension`.
     fn make_out_name(&self, extension: &str) -> PathBuf {
         self.output_base_name().with_extension(extension)
     }
 
-    /// Directory where auxiliary files are written.  Example:
-    ///   /.../testname.revision.mode/auxiliary/
+    /// Gets the directory where auxiliary files are written.
+    /// E.g., `/.../testname.revision.mode/auxiliary/`.
     fn aux_output_dir_name(&self) -> PathBuf {
         self.output_base_dir()
             .join("auxiliary")
@@ -1955,7 +1993,7 @@ impl<'test> TestCx<'test> {
         output_testname_unique(self.config, self.testpaths, self.safe_revision())
     }
 
-    /// The revision, ignored for Incremental since it wants all revisions in
+    /// The revision, ignored for incremental compilation since it wants all revisions in
     /// the same directory.
     fn safe_revision(&self) -> Option<&str> {
         if self.config.mode == Incremental {
@@ -1965,16 +2003,16 @@ impl<'test> TestCx<'test> {
         }
     }
 
-    /// Absolute path to the directory where all output for the given
-    /// test/revision should reside.  Example:
-    ///   /path/to/build/host-triple/test/ui/relative/testname.revision.mode/
+    /// Gets the absolute path to the directory where all output for the given
+    /// test/revision should reside.
+    /// E.g., `/path/to/build/host-triple/test/ui/relative/testname.revision.mode/`.
     fn output_base_dir(&self) -> PathBuf {
         output_base_dir(self.config, self.testpaths, self.safe_revision())
     }
 
-    /// Absolute path to the base filename used as output for the given
-    /// test/revision.  Example:
-    ///   /.../relative/testname.revision.mode/testname
+    /// Gets the absolute path to the base filename used as output for the given
+    /// test/revision.
+    /// E.g., `/.../relative/testname.revision.mode/testname`.
     fn output_base_name(&self) -> PathBuf {
         output_base_name(self.config, self.testpaths, self.safe_revision())
     }
@@ -1998,7 +2036,8 @@ impl<'test> TestCx<'test> {
 
     fn fatal(&self, err: &str) -> ! {
         self.error(err);
-        panic!();
+        error!("fatal error, panic: {:?}", err);
+        panic!("fatal error");
     }
 
     fn fatal_proc_rec(&self, err: &str, proc_res: &ProcRes) -> ! {
@@ -2065,12 +2104,19 @@ impl<'test> TestCx<'test> {
             .arg("--input-file")
             .arg(irfile)
             .arg(&self.testpaths.file);
+        // It would be more appropriate to make most of the arguments configurable through
+        // a comment-attribute similar to `compile-flags`. For example, --check-prefixes is a very
+        // useful flag.
+        //
+        // For now, though…
+        if let Some(rev) = self.revision {
+            let prefixes = format!("CHECK,{}", rev);
+            filecheck.args(&["--check-prefixes", &prefixes]);
+        }
         self.compose_and_run(filecheck, "", None, None)
     }
 
     fn run_codegen_test(&self) {
-        assert!(self.revision.is_none(), "revisions not relevant here");
-
         if self.config.llvm_filecheck.is_none() {
             self.fatal("missing --llvm-filecheck");
         }
@@ -2587,6 +2633,10 @@ impl<'test> TestCx<'test> {
             cmd.env("RUSTC_LINKER", linker);
         }
 
+        if let Some(ref clang) = self.config.run_clang_based_tests_with {
+            cmd.env("CLANG", clang);
+        }
+
         // We don't want RUSTFLAGS set from the outside to interfere with
         // compiler flags set in the test cases:
         cmd.env_remove("RUSTFLAGS");
@@ -3205,7 +3255,7 @@ impl<'test> TestCx<'test> {
     }
 
     fn create_stamp(&self) {
-        let stamp = ::stamp(&self.config, self.testpaths, self.revision);
+        let stamp = crate::stamp(&self.config, self.testpaths, self.revision);
         fs::write(&stamp, compute_stamp_hash(&self.config)).unwrap();
     }
 }
@@ -3261,7 +3311,7 @@ impl<T> fmt::Debug for ExpectedLine<T>
 where
     T: AsRef<str> + fmt::Debug,
 {
-    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         if let &ExpectedLine::Text(ref t) = self {
             write!(formatter, "{:?}", t)
         } else {
@@ -3284,7 +3334,7 @@ fn nocomment_mir_line(line: &str) -> &str {
 }
 
 fn read2_abbreviated(mut child: Child) -> io::Result<Output> {
-    use read2::read2;
+    use crate::read2::read2;
     use std::mem::replace;
 
     const HEAD_LEN: usize = 160 * 1024;
diff --git a/src/tools/compiletest/src/util.rs b/src/tools/compiletest/src/util.rs
index 90dfadeee4612..240287fa248bd 100644
--- a/src/tools/compiletest/src/util.rs
+++ b/src/tools/compiletest/src/util.rs
@@ -1,7 +1,7 @@
 use std::ffi::OsStr;
 use std::env;
 use std::path::PathBuf;
-use common::Config;
+use crate::common::Config;
 
 /// Conversion table from triple OS name to Rust SYSNAME
 const OS_TABLE: &'static [(&'static str, &'static str)] = &[
@@ -9,6 +9,7 @@ const OS_TABLE: &'static [(&'static str, &'static str)] = &[
     ("androideabi", "android"),
     ("bitrig", "bitrig"),
     ("cloudabi", "cloudabi"),
+    ("cuda", "cuda"),
     ("darwin", "macos"),
     ("dragonfly", "dragonfly"),
     ("emscripten", "emscripten"),
@@ -20,9 +21,11 @@ const OS_TABLE: &'static [(&'static str, &'static str)] = &[
     ("l4re", "l4re"),
     ("linux", "linux"),
     ("mingw32", "windows"),
+    ("none", "none"),
     ("netbsd", "netbsd"),
     ("openbsd", "openbsd"),
     ("redox", "redox"),
+    ("sgx", "sgx"),
     ("solaris", "solaris"),
     ("win32", "windows"),
     ("windows", "windows"),
@@ -38,6 +41,7 @@ const ARCH_TABLE: &'static [(&'static str, &'static str)] = &[
     ("armv7", "arm"),
     ("armv7s", "arm"),
     ("asmjs", "asmjs"),
+    ("cuda", "cuda"),
     ("hexagon", "hexagon"),
     ("i386", "x86"),
     ("i586", "x86"),
@@ -154,6 +158,7 @@ fn test_get_arch_failure() {
 fn test_get_arch() {
     assert_eq!("x86_64", get_arch("x86_64-unknown-linux-gnu"));
     assert_eq!("x86_64", get_arch("amd64"));
+    assert_eq!("cuda", get_arch("nvptx64-nvidia-cuda"));
 }
 
 #[test]
@@ -168,4 +173,8 @@ fn test_matches_os() {
     assert!(matches_os("wasm32-unknown-unknown", "emscripten"));
     assert!(matches_os("wasm32-unknown-unknown", "wasm32-bare"));
     assert!(!matches_os("wasm32-unknown-unknown", "windows"));
+    assert!(matches_os("thumbv6m0-none-eabi", "none"));
+    assert!(matches_os("riscv32imc-unknown-none-elf", "none"));
+    assert!(matches_os("nvptx64-nvidia-cuda", "cuda"));
+    assert!(matches_os("x86_64-fortanix-unknown-sgx", "sgx"));
 }
diff --git a/src/tools/error_index_generator/Cargo.toml b/src/tools/error_index_generator/Cargo.toml
index 7f8783c9d89be..116be234f3ceb 100644
--- a/src/tools/error_index_generator/Cargo.toml
+++ b/src/tools/error_index_generator/Cargo.toml
@@ -2,6 +2,7 @@
 authors = ["The Rust Project Developers"]
 name = "error_index_generator"
 version = "0.0.0"
+edition = "2018"
 
 [dependencies]
 rustdoc = { path = "../../librustdoc" }
diff --git a/src/tools/error_index_generator/main.rs b/src/tools/error_index_generator/main.rs
index 72cfd7d5e58e9..faeeea605a2b4 100644
--- a/src/tools/error_index_generator/main.rs
+++ b/src/tools/error_index_generator/main.rs
@@ -1,8 +1,9 @@
 #![feature(rustc_private)]
 
+#![deny(rust_2018_idioms)]
+
 extern crate env_logger;
 extern crate syntax;
-extern crate rustdoc;
 extern crate serialize as rustc_serialize;
 
 use std::collections::BTreeMap;
@@ -193,7 +194,7 @@ impl Formatter for MarkdownFormatter {
     }
 }
 
-/// Load all the metadata files from `metadata_dir` into an in-memory map.
+/// Loads all the metadata files from `metadata_dir` into an in-memory map.
 fn load_all_errors(metadata_dir: &Path) -> Result<ErrorMetadataMap, Box<dyn Error>> {
     let mut all_errors = BTreeMap::new();
 
diff --git a/src/tools/linkchecker/Cargo.toml b/src/tools/linkchecker/Cargo.toml
index d6b7dafea40e0..0994cd2066246 100644
--- a/src/tools/linkchecker/Cargo.toml
+++ b/src/tools/linkchecker/Cargo.toml
@@ -2,6 +2,7 @@
 name = "linkchecker"
 version = "0.1.0"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
+edition = "2018"
 
 [[bin]]
 name = "linkchecker"
diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
index 59662be349dcb..af704ce260dc4 100644
--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -14,6 +14,8 @@
 //! A few whitelisted exceptions are allowed as there's known bugs in rustdoc,
 //! but this should catch the majority of "broken link" cases.
 
+#![deny(rust_2018_idioms)]
+
 use std::collections::hash_map::Entry;
 use std::collections::{HashMap, HashSet};
 use std::env;
@@ -21,7 +23,7 @@ use std::fs;
 use std::path::{Path, PathBuf, Component};
 use std::rc::Rc;
 
-use Redirect::*;
+use crate::Redirect::*;
 
 macro_rules! t {
     ($e:expr) => (match $e {
@@ -78,7 +80,7 @@ impl FileEntry {
     fn parse_ids(&mut self, file: &Path, contents: &str, errors: &mut bool) {
         if self.ids.is_empty() {
             with_attrs_in_source(contents, " id", |fragment, i, _| {
-                let frag = fragment.trim_left_matches("#").to_owned();
+                let frag = fragment.trim_start_matches("#").to_owned();
                 let encoded = small_url_encode(&frag);
                 if !self.ids.insert(frag) {
                     *errors = true;
@@ -343,7 +345,7 @@ fn with_attrs_in_source<F: FnMut(&str, usize, &str)>(contents: &str, attr: &str,
                 Some(i) => i,
                 None => continue,
             };
-            if rest[..pos_equals].trim_left_matches(" ") != "" {
+            if rest[..pos_equals].trim_start_matches(" ") != "" {
                 continue;
             }
 
@@ -355,7 +357,7 @@ fn with_attrs_in_source<F: FnMut(&str, usize, &str)>(contents: &str, attr: &str,
             };
             let quote_delim = rest.as_bytes()[pos_quote] as char;
 
-            if rest[..pos_quote].trim_left_matches(" ") != "" {
+            if rest[..pos_quote].trim_start_matches(" ") != "" {
                 continue;
             }
             let rest = &rest[pos_quote + 1..];
diff --git a/src/tools/lld b/src/tools/lld
deleted file mode 160000
index 1928c5eeb613a..0000000000000
--- a/src/tools/lld
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 1928c5eeb613a4c6d232fc47ae91914bbfd92a79
diff --git a/src/tools/lldb b/src/tools/lldb
deleted file mode 160000
index 8ad0817ce45b0..0000000000000
--- a/src/tools/lldb
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 8ad0817ce45b0eef9d374691b23f2bd69c164254
diff --git a/src/tools/miri b/src/tools/miri
index 97f4cff8e904c..76138c56575c3 160000
--- a/src/tools/miri
+++ b/src/tools/miri
@@ -1 +1 @@
-Subproject commit 97f4cff8e904c268569d37922a27835209deff5d
+Subproject commit 76138c56575c347207039bdeafb8456bd72116ad
diff --git a/src/tools/publish_toolstate.py b/src/tools/publish_toolstate.py
index 323f81181682f..fb6132a5358ef 100755
--- a/src/tools/publish_toolstate.py
+++ b/src/tools/publish_toolstate.py
@@ -15,15 +15,26 @@
 # List of people to ping when the status of a tool changed.
 MAINTAINERS = {
     'miri': '@oli-obk @RalfJung @eddyb',
-    'clippy-driver': '@Manishearth @llogiq @mcarton @oli-obk',
+    'clippy-driver': '@Manishearth @llogiq @mcarton @oli-obk @phansch',
     'rls': '@nrc @Xanewok',
-    'rustfmt': '@nrc',
+    'rustfmt': '@nrc @topecongiro',
     'book': '@carols10cents @steveklabnik',
     'nomicon': '@frewsxcv @Gankro',
     'reference': '@steveklabnik @Havvy @matthewjasper @alercah',
     'rust-by-example': '@steveklabnik @marioidival @projektir',
 }
 
+REPOS = {
+    'miri': 'https://github.com/rust-lang/miri',
+    'clippy-driver': 'https://github.com/rust-lang/rust-clippy',
+    'rls': 'https://github.com/rust-lang/rls',
+    'rustfmt': 'https://github.com/rust-lang/rustfmt',
+    'book': 'https://github.com/rust-lang/book',
+    'nomicon': 'https://github.com/rust-lang-nursery/nomicon',
+    'reference': 'https://github.com/rust-lang-nursery/reference',
+    'rust-by-example': 'https://github.com/rust-lang/rust-by-example',
+}
+
 
 def read_current_status(current_commit, path):
     '''Reads build status of `current_commit` from content of `history/*.tsv`
@@ -35,11 +46,48 @@ def read_current_status(current_commit, path):
                 return json.loads(status)
     return {}
 
+def issue(
+    tool,
+    maintainers,
+    relevant_pr_number,
+    relevant_pr_user,
+    pr_reviewer,
+):
+    # Open an issue about the toolstate failure.
+    gh_url = 'https://api.github.com/repos/rust-lang/rust/issues'
+    assignees = [x.strip() for x in maintainers.split('@') if x != '']
+    assignees.append(relevant_pr_user)
+    response = urllib2.urlopen(urllib2.Request(
+        gh_url,
+        json.dumps({
+            'body': textwrap.dedent('''\
+            Hello, this is your friendly neighborhood mergebot.
+            After merging PR {}, I observed that the tool {} no longer builds.
+            A follow-up PR to the repository {} is needed to fix the fallout.
+
+            cc @{}, do you think you would have time to do the follow-up work?
+            If so, that would be great!
+
+            cc @{}, the PR reviewer, and @rust-lang/compiler -- nominating for prioritization.
+
+            ''').format(relevant_pr_number, tool, REPOS[tool], relevant_pr_user, pr_reviewer),
+            'title': '`{}` no longer builds after {}'.format(tool, relevant_pr_number),
+            'assignees': assignees,
+            'labels': ['T-compiler', 'I-nominated'],
+        }),
+        {
+            'Authorization': 'token ' + github_token,
+            'Content-Type': 'application/json',
+        }
+    ))
+    response.read()
 
 def update_latest(
     current_commit,
     relevant_pr_number,
     relevant_pr_url,
+    relevant_pr_user,
+    pr_reviewer,
     current_datetime
 ):
     '''Updates `_data/latest.json` to match build result of the given commit.
@@ -64,19 +112,41 @@ def update_latest(
         for status in latest:
             tool = status['tool']
             changed = False
+            build_failed = False
 
             for os, s in current_status.items():
                 old = status[os]
                 new = s.get(tool, old)
                 status[os] = new
                 if new > old:
+                    # things got fixed or at least the status quo improved
                     changed = True
                     message += '🎉 {} on {}: {} → {} (cc {}, @rust-lang/infra).\n' \
                         .format(tool, os, old, new, MAINTAINERS.get(tool))
                 elif new < old:
+                    # tests or builds are failing and were not failing before
                     changed = True
-                    message += '💔 {} on {}: {} → {} (cc {}, @rust-lang/infra).\n' \
-                        .format(tool, os, old, new, MAINTAINERS.get(tool))
+                    title = '💔 {} on {}: {} → {}' \
+                        .format(tool, os, old, new)
+                    message += '{} (cc {}, @rust-lang/infra).\n' \
+                        .format(title, MAINTAINERS.get(tool))
+                    # only create issues for build failures. Other failures can be spurious
+                    if new == 'build-fail':
+                        build_failed = True
+
+            if build_failed:
+                try:
+                    issue(
+                        tool, MAINTAINERS.get(tool),
+                        relevant_pr_number, relevant_pr_user, pr_reviewer,
+                    )
+                except IOError as e:
+                    # network errors will simply end up not creating an issue, but that's better
+                    # than failing the entire build job
+                    print("I/O error: {0}".format(e))
+                except:
+                    print("Unexpected error: {0}".format(sys.exc_info()[0]))
+                    raise
 
             if changed:
                 status['commit'] = current_commit
@@ -99,20 +169,30 @@ def update_latest(
     save_message_to_path = sys.argv[3]
     github_token = sys.argv[4]
 
-    relevant_pr_match = re.search('#([0-9]+)', cur_commit_msg)
+    # assume that PR authors are also owners of the repo where the branch lives
+    relevant_pr_match = re.search(
+        r'Auto merge of #([0-9]+) - ([^:]+):[^,]+, r=(\S+)',
+        cur_commit_msg,
+    )
     if relevant_pr_match:
         number = relevant_pr_match.group(1)
+        relevant_pr_user = relevant_pr_match.group(2)
         relevant_pr_number = 'rust-lang/rust#' + number
         relevant_pr_url = 'https://github.com/rust-lang/rust/pull/' + number
+        pr_reviewer = relevant_pr_match.group(3)
     else:
         number = '-1'
+        relevant_pr_user = 'ghost'
         relevant_pr_number = '<unknown PR>'
         relevant_pr_url = '<unknown>'
+        pr_reviewer = 'ghost'
 
     message = update_latest(
         cur_commit,
         relevant_pr_number,
         relevant_pr_url,
+        relevant_pr_user,
+        pr_reviewer,
         cur_datetime
     )
     if not message:
diff --git a/src/tools/remote-test-client/Cargo.toml b/src/tools/remote-test-client/Cargo.toml
index 54739101f1eff..1a4b24bd5b34c 100644
--- a/src/tools/remote-test-client/Cargo.toml
+++ b/src/tools/remote-test-client/Cargo.toml
@@ -2,5 +2,6 @@
 name = "remote-test-client"
 version = "0.1.0"
 authors = ["The Rust Project Developers"]
+edition = "2018"
 
 [dependencies]
diff --git a/src/tools/remote-test-server/Cargo.toml b/src/tools/remote-test-server/Cargo.toml
index 8704296289e83..5906c76c01d9f 100644
--- a/src/tools/remote-test-server/Cargo.toml
+++ b/src/tools/remote-test-server/Cargo.toml
@@ -2,5 +2,6 @@
 name = "remote-test-server"
 version = "0.1.0"
 authors = ["The Rust Project Developers"]
+edition = "2018"
 
 [dependencies]
diff --git a/src/tools/remote-test-server/src/main.rs b/src/tools/remote-test-server/src/main.rs
index 74dde8bf0e2c9..750eea3a28aef 100644
--- a/src/tools/remote-test-server/src/main.rs
+++ b/src/tools/remote-test-server/src/main.rs
@@ -20,7 +20,7 @@ use std::os::unix::prelude::*;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 use std::str;
-use std::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::{Arc, Mutex};
 use std::thread;
 
@@ -31,7 +31,7 @@ macro_rules! t {
     })
 }
 
-static TEST: AtomicUsize = ATOMIC_USIZE_INIT;
+static TEST: AtomicUsize = AtomicUsize::new(0);
 
 struct Config {
     pub remote: bool,
@@ -174,7 +174,7 @@ fn handle_run(socket: TcpStream, work: &Path, lock: &Mutex<()>) {
     // other thread created a child process with the file open for writing, and
     // we attempt to execute it, so we get an error.
     //
-    // This race is resolve by ensuring that only one thread can writ ethe file
+    // This race is resolve by ensuring that only one thread can write the file
     // and spawn a child process at once. Kinda an unfortunate solution, but we
     // don't have many other choices with this sort of setup!
     //
diff --git a/src/tools/rls b/src/tools/rls
index ae0d89a08d091..0d6f53e1a4adb 160000
--- a/src/tools/rls
+++ b/src/tools/rls
@@ -1 +1 @@
-Subproject commit ae0d89a08d091ba1563b571739768a09d4cd3d69
+Subproject commit 0d6f53e1a4adbaf7d83cdc0cb54720203fcb522e
diff --git a/src/tools/rust-installer b/src/tools/rust-installer
index 27dec6cae3a81..ccdc47b657a76 160000
--- a/src/tools/rust-installer
+++ b/src/tools/rust-installer
@@ -1 +1 @@
-Subproject commit 27dec6cae3a8132d8a073aad6775425c85095c99
+Subproject commit ccdc47b657a7600cbd0c2858eb52a8d712cfce18
diff --git a/src/tools/rustbook/Cargo.toml b/src/tools/rustbook/Cargo.toml
index 5e11646ee4c19..5bf1553b22711 100644
--- a/src/tools/rustbook/Cargo.toml
+++ b/src/tools/rustbook/Cargo.toml
@@ -3,11 +3,19 @@ authors = ["The Rust Project Developers"]
 name = "rustbook"
 version = "0.1.0"
 license = "MIT/Apache-2.0"
+edition = "2018"
 
 [dependencies]
 clap = "2.25.0"
 
-[dependencies.mdbook]
+[dependencies.mdbook_2]
+package = "mdbook"
+version = "0.2.3"
+default-features = false
+features = ["search"]
+
+[dependencies.mdbook_1]
+package = "mdbook"
 version = "0.1.7"
 default-features = false
 features = ["search"]
diff --git a/src/tools/rustbook/src/main.rs b/src/tools/rustbook/src/main.rs
index 80a85dc2ac0e3..5a6246347cc03 100644
--- a/src/tools/rustbook/src/main.rs
+++ b/src/tools/rustbook/src/main.rs
@@ -1,21 +1,24 @@
 //
-extern crate mdbook;
-#[macro_use]
-extern crate clap;
+use clap::{crate_version};
 
 use std::env;
 use std::path::{Path, PathBuf};
 
 use clap::{App, ArgMatches, SubCommand, AppSettings};
 
-use mdbook::MDBook;
-use mdbook::errors::Result;
+use mdbook_1::{MDBook as MDBook1};
+use mdbook_1::errors::{Result as Result1};
+
+use mdbook_2::{MDBook as MDBook2};
+use mdbook_2::errors::{Result as Result2};
 
 fn main() {
     let d_message = "-d, --dest-dir=[dest-dir]
 'The output directory for your book{n}(Defaults to ./book when omitted)'";
     let dir_message = "[dir]
 'A directory for your book{n}(Defaults to Current Directory when omitted)'";
+    let vers_message = "-m, --mdbook-vers=[md-version]
+'The version of mdbook to use for your book{n}(Defaults to 1 when omitted)'";
 
     let matches = App::new("rustbook")
                     .about("Build a book with mdBook")
@@ -25,29 +28,66 @@ fn main() {
                     .subcommand(SubCommand::with_name("build")
                         .about("Build the book from the markdown files")
                         .arg_from_usage(d_message)
-                        .arg_from_usage(dir_message))
+                        .arg_from_usage(dir_message)
+                        .arg_from_usage(vers_message))
                     .get_matches();
 
     // Check which subcomamnd the user ran...
-    let res = match matches.subcommand() {
-        ("build", Some(sub_matches)) => build(sub_matches),
+    match matches.subcommand() {
+        ("build", Some(sub_matches)) => {
+            match sub_matches.value_of("mdbook-vers") {
+                None | Some("1") => {
+                    if let Err(e) = build_1(sub_matches) {
+                        eprintln!("Error: {}", e);
+
+                        for cause in e.iter().skip(1) {
+                            eprintln!("\tCaused By: {}", cause);
+                        }
+
+                        ::std::process::exit(101);
+                    }
+                }
+                Some("2") => {
+                    if let Err(e) = build_2(sub_matches) {
+                        eprintln!("Error: {}", e);
+
+                        for cause in e.iter().skip(1) {
+                            eprintln!("\tCaused By: {}", cause);
+                        }
+
+                        ::std::process::exit(101);
+                    }
+                }
+                _ => {
+                    panic!("Invalid mdBook version! Select '1' or '2'");
+                }
+            };
+        },
         (_, _) => unreachable!(),
     };
+}
 
-    if let Err(e) = res {
-        eprintln!("Error: {}", e);
+// Build command implementation
+pub fn build_1(args: &ArgMatches) -> Result1<()> {
+    let book_dir = get_book_dir(args);
+    let mut book = MDBook1::load(&book_dir)?;
 
-        for cause in e.iter().skip(1) {
-            eprintln!("\tCaused By: {}", cause);
-        }
+    // Set this to allow us to catch bugs in advance.
+    book.config.build.create_missing = false;
 
-        ::std::process::exit(101);
+    if let Some(dest_dir) = args.value_of("dest-dir") {
+        book.config.build.build_dir = PathBuf::from(dest_dir);
     }
+
+    book.build()?;
+
+    Ok(())
 }
+
 // Build command implementation
-pub fn build(args: &ArgMatches) -> Result<()> {
+pub fn build_2(args: &ArgMatches) -> Result2<()> {
     let book_dir = get_book_dir(args);
-    let mut book = MDBook::load(&book_dir)?;
+    let mut book = MDBook2::load(&book_dir)?;
 
     // Set this to allow us to catch bugs in advance.
     book.config.build.create_missing = false;
diff --git a/src/tools/rustc-std-workspace-core/Cargo.toml b/src/tools/rustc-std-workspace-core/Cargo.toml
index f000d634e1943..d527ce12bc3a1 100644
--- a/src/tools/rustc-std-workspace-core/Cargo.toml
+++ b/src/tools/rustc-std-workspace-core/Cargo.toml
@@ -6,6 +6,7 @@ license = 'MIT/Apache-2.0'
 description = """
 Hack for the compiler's own build system
 """
+edition = "2018"
 
 [lib]
 path = "lib.rs"
diff --git a/src/tools/rustc-std-workspace-core/lib.rs b/src/tools/rustc-std-workspace-core/lib.rs
index e2946fe2a97f1..99d51bc2d56ac 100644
--- a/src/tools/rustc-std-workspace-core/lib.rs
+++ b/src/tools/rustc-std-workspace-core/lib.rs
@@ -1,6 +1,5 @@
 #![feature(no_core)]
 #![no_core]
-
-extern crate core;
+#![deny(rust_2018_idioms)]
 
 pub use core::*;
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index c4499ef95ad8e..157b731170738 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -6,6 +6,7 @@ license = 'MIT/Apache-2.0'
 description = """
 Hack for the compiler's own build system
 """
+edition = "2018"
 
 [lib]
 path = "lib.rs"
@@ -45,6 +46,7 @@ features = [
   "sspi",
   "synchapi",
   "sysinfoapi",
+  "threadpoollegacyapiset",
   "timezoneapi",
   "userenv",
   "winbase",
@@ -58,7 +60,7 @@ parking_lot = { version = "0.6", features = ['nightly'] }
 rand = { version = "0.5.5", features = ["i128_support"] }
 serde = { version = "1.0.82", features = ['derive'] }
 serde_json = { version = "1.0.31", features = ["raw_value"] }
-smallvec = { version = "0.6", features = ['union'] }
+smallvec = { version = "0.6", features = ['union', 'may_dangle'] }
 scopeguard = { version = "0.3.3", features = ["use_std", "default"]}
 byteorder = { version = "1.2.7", features = ["i128"]}
 
diff --git a/src/tools/rustdoc-themes/Cargo.toml b/src/tools/rustdoc-themes/Cargo.toml
index c0e2f527301be..c12a20fd56c7b 100644
--- a/src/tools/rustdoc-themes/Cargo.toml
+++ b/src/tools/rustdoc-themes/Cargo.toml
@@ -2,6 +2,7 @@
 name = "rustdoc-themes"
 version = "0.1.0"
 authors = ["Guillaume Gomez <guillaume1.gomez@gmail.com>"]
+edition = "2018"
 
 [[bin]]
 name = "rustdoc-themes"
diff --git a/src/tools/rustdoc-themes/main.rs b/src/tools/rustdoc-themes/main.rs
index 616b5444832c1..63432a6585a84 100644
--- a/src/tools/rustdoc-themes/main.rs
+++ b/src/tools/rustdoc-themes/main.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 use std::env::args;
 use std::fs::read_dir;
 use std::path::Path;
diff --git a/src/tools/rustdoc/Cargo.toml b/src/tools/rustdoc/Cargo.toml
index d38815004418c..36aa5916da733 100644
--- a/src/tools/rustdoc/Cargo.toml
+++ b/src/tools/rustdoc/Cargo.toml
@@ -2,6 +2,7 @@
 name = "rustdoc-tool"
 version = "0.0.0"
 authors = ["The Rust Project Developers"]
+edition = "2018"
 
 # Cargo adds a number of paths to the dylib search path on windows, which results in
 # the wrong rustdoc being executed. To avoid the conflicting rustdocs, we name the "tool"
diff --git a/src/tools/rustdoc/main.rs b/src/tools/rustdoc/main.rs
index df9d2c6ba96db..8bdc365c4ca68 100644
--- a/src/tools/rustdoc/main.rs
+++ b/src/tools/rustdoc/main.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 #![feature(link_args)]
 
 #[allow(unused_attributes)]
@@ -10,6 +12,4 @@
 // See src/rustc/rustc.rs for the corresponding rustc settings.
 extern {}
 
-extern crate rustdoc;
-
 fn main() { rustdoc::main() }
diff --git a/src/tools/rustfmt b/src/tools/rustfmt
index be135599ef5e5..d6829d62dca64 160000
--- a/src/tools/rustfmt
+++ b/src/tools/rustfmt
@@ -1 +1 @@
-Subproject commit be135599ef5e54b5219f9adec68e1ee267ea0584
+Subproject commit d6829d62dca64dfe7ceaa96d1a9c1cd36428221d
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index f1bfb6efc2f07..94dd5478e5297 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -26,6 +26,7 @@ const EXCEPTIONS: &[&str] = &[
     "mdbook",             // MPL2, mdbook
     "openssl",            // BSD+advertising clause, cargo, mdbook
     "pest",               // MPL2, mdbook via handlebars
+    "arrayref",           // BSD-2-Clause, mdbook via handlebars via pest
     "thread-id",          // Apache-2.0, mdbook
     "toml-query",         // MPL-2.0, mdbook
     "is-match",           // MPL-2.0, mdbook
@@ -44,6 +45,7 @@ const EXCEPTIONS: &[&str] = &[
     "im-rc",              // MPL-2.0+, cargo
     "adler32",            // BSD-3-Clause AND Zlib, cargo dep that isn't used
     "fortanix-sgx-abi",   // MPL-2.0+, libstd but only for `sgx` target
+    "constant_time_eq",   // CC0-1.0, rustfmt
 ];
 
 /// Which crates to check against the whitelist?
diff --git a/src/tools/tidy/src/features.rs b/src/tools/tidy/src/features.rs
index 16f2e3ba27dbb..7126c0c2f6ecf 100644
--- a/src/tools/tidy/src/features.rs
+++ b/src/tools/tidy/src/features.rs
@@ -188,7 +188,7 @@ pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
             }
 
             let mut parts = line.split(',');
-            let level = match parts.next().map(|l| l.trim().trim_left_matches('(')) {
+            let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
                 Some("active") => Status::Unstable,
                 Some("removed") => Status::Removed,
                 Some("accepted") => Status::Stable,
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index a10332526d13b..022c53f909c75 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -47,6 +47,7 @@ pub mod libcoretest;
 fn filter_dirs(path: &Path) -> bool {
     let skip = [
         "src/llvm",
+        "src/llvm-project",
         "src/llvm-emscripten",
         "src/libbacktrace",
         "src/librustc_data_structures/owning_ref",
diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index 81b7b2a7731ae..6622403826665 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -4,6 +4,7 @@
 //! etc. This is run by default on `make check` and as part of the auto
 //! builders.
 
+#![deny(rust_2018_idioms)]
 #![deny(warnings)]
 
 extern crate tidy;
diff --git a/src/tools/tidy/src/pal.rs b/src/tools/tidy/src/pal.rs
index ce5e15af2f97c..ed2218f09d26b 100644
--- a/src/tools/tidy/src/pal.rs
+++ b/src/tools/tidy/src/pal.rs
@@ -52,10 +52,13 @@ const EXCEPTION_PATHS: &[&str] = &[
     "src/libstd/path.rs",
     "src/libstd/f32.rs",
     "src/libstd/f64.rs",
+    // Integration test for platform-specific run-time feature detection:
+    "src/libstd/tests/run-time-detect.rs" ,
     "src/libstd/sys_common/mod.rs",
     "src/libstd/sys_common/net.rs",
     "src/libterm", // Not sure how to make this crate portable, but test crate needs it.
     "src/libtest", // Probably should defer to unstable `std::sys` APIs.
+    "src/libstd/sync/mpsc", // some tests are only run on non-emscripten
 
     // std testing crates, okay for now at least
     "src/libcore/tests",
diff --git a/src/tools/tidy/src/style.rs b/src/tools/tidy/src/style.rs
index df54afe160b33..a4321cd757129 100644
--- a/src/tools/tidy/src/style.rs
+++ b/src/tools/tidy/src/style.rs
@@ -44,7 +44,7 @@ enum LIUState {
     EXP_END,
 }
 
-/// Returns whether `line` appears to be a line comment containing an URL,
+/// Returns `true` if `line` appears to be a line comment containing an URL,
 /// possibly with a Markdown link label in front, and nothing else.
 /// The Markdown link label, if present, may not contain whitespace.
 /// Lines of this form are allowed to be overlength, because Markdown
@@ -79,7 +79,7 @@ fn line_is_url(line: &str) -> bool {
     state == EXP_END
 }
 
-/// Returns whether `line` is allowed to be longer than the normal limit.
+/// Returns `true` if `line` is allowed to be longer than the normal limit.
 /// Currently there is only one exception, for long URLs, but more
 /// may be added in the future.
 fn long_line_is_ok(line: &str) -> bool {
diff --git a/src/tools/tidy/src/unstable_book.rs b/src/tools/tidy/src/unstable_book.rs
index bd3b1f033c761..63196eda7cc5f 100644
--- a/src/tools/tidy/src/unstable_book.rs
+++ b/src/tools/tidy/src/unstable_book.rs
@@ -1,7 +1,7 @@
 use std::collections::BTreeSet;
 use std::fs;
 use std::path;
-use features::{collect_lang_features, collect_lib_features, Features, Status};
+use crate::features::{collect_lang_features, collect_lib_features, Features, Status};
 
 pub const PATH_STR: &str = "doc/unstable-book/src";
 
@@ -56,7 +56,7 @@ pub fn collect_unstable_book_section_file_names(dir: &path::Path) -> BTreeSet<St
         .collect()
 }
 
-/// Retrieve file names of all library feature sections in the Unstable Book with:
+/// Retrieves file names of all library feature sections in the Unstable Book with:
 ///
 /// * hyphens replaced by underscores,
 /// * the markdown suffix ('.md') removed.
diff --git a/src/tools/unstable-book-gen/Cargo.toml b/src/tools/unstable-book-gen/Cargo.toml
index 2839f93f8e279..3209de09aeb68 100644
--- a/src/tools/unstable-book-gen/Cargo.toml
+++ b/src/tools/unstable-book-gen/Cargo.toml
@@ -4,6 +4,7 @@ authors = ["est31 <MTest31@outlook.com>",
 name = "unstable-book-gen"
 version = "0.1.0"
 license = "MIT/Apache-2.0"
+edition = "2018"
 
 [dependencies]
 tidy = { path = "../tidy" }
diff --git a/src/tools/unstable-book-gen/src/main.rs b/src/tools/unstable-book-gen/src/main.rs
index df12eaf0cb028..427014ce7fe55 100644
--- a/src/tools/unstable-book-gen/src/main.rs
+++ b/src/tools/unstable-book-gen/src/main.rs
@@ -1,8 +1,9 @@
 //! Auto-generate stub docs for the unstable book
 
+#![deny(rust_2018_idioms)]
 #![deny(warnings)]
 
-extern crate tidy;
+
 
 use tidy::features::{Feature, Features, collect_lib_features, collect_lang_features};
 use tidy::unstable_book::{collect_unstable_feature_names, collect_unstable_book_section_file_names,