Auto merge of #74929 - Manishearth:rollup-z2vflrp, r=Manishearth

Rollup of 10 pull requests

Successful merges:

 - #74742 (Remove links to rejected errata 4406 for RFC 4291)
 - #74819 (Point towards `format_spec`; it is in other direction)
 - #74852 (Explain why inlining default ToString impl)
 - #74869 (Make closures and generators a must use types)
 - #74873 (symbol mangling: use ty::print::Print for consts)
 - #74902 (Remove deprecated unstable `{Box,Rc,Arc}::into_raw_non_null` functions)
 - #74904 (Fix some typos in src/librustdoc/clean/auto_trait.rs)
 - #74910 (fence docs: fix example Mutex)
 - #74912 (Fix broken link in unstable book `plugin`)
 - #74927 (Change the target data layout to specify more values)

Failed merges:

r? @ghost

Author: bors

library/alloc/src/boxed.rs

@@ -143,7 +143,7 @@ use core::ops::{
     CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
 };
 use core::pin::Pin;
-use core::ptr::{self, NonNull, Unique};
+use core::ptr::{self, Unique};
 use core::task::{Context, Poll};
 
 use crate::alloc::{self, AllocInit, AllocRef, Global};
@@ -451,50 +451,6 @@ impl<T: ?Sized> Box<T> {
         Box::leak(b) as *mut T
     }
 
-    /// Consumes the `Box`, returning the wrapped pointer as `NonNull<T>`.
-    ///
-    /// After calling this function, the caller is responsible for the
-    /// memory previously managed by the `Box`. In particular, the
-    /// caller should properly destroy `T` and release the memory. The
-    /// easiest way to do so is to convert the `NonNull<T>` pointer
-    /// into a raw pointer and back into a `Box` with the [`Box::from_raw`]
-    /// function.
-    ///
-    /// Note: this is an associated function, which means that you have
-    /// to call it as `Box::into_raw_non_null(b)`
-    /// instead of `b.into_raw_non_null()`. This
-    /// is so that there is no conflict with a method on the inner type.
-    ///
-    /// [`Box::from_raw`]: struct.Box.html#method.from_raw
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(box_into_raw_non_null)]
-    /// #![allow(deprecated)]
-    ///
-    /// let x = Box::new(5);
-    /// let ptr = Box::into_raw_non_null(x);
-    ///
-    /// // Clean up the memory by converting the NonNull pointer back
-    /// // into a Box and letting the Box be dropped.
-    /// let x = unsafe { Box::from_raw(ptr.as_ptr()) };
-    /// ```
-    #[unstable(feature = "box_into_raw_non_null", issue = "47336")]
-    #[rustc_deprecated(
-        since = "1.44.0",
-        reason = "use `Box::leak(b).into()` or `NonNull::from(Box::leak(b))` instead"
-    )]
-    #[inline]
-    pub fn into_raw_non_null(b: Box<T>) -> NonNull<T> {
-        // Box is recognized as a "unique pointer" by Stacked Borrows, but internally it is a
-        // raw pointer for the type system. Turning it directly into a raw pointer would not be
-        // recognized as "releasing" the unique pointer to permit aliased raw accesses,
-        // so all raw pointer methods go through `leak` which creates a (unique)
-        // mutable reference. Turning *that* to a raw pointer behaves correctly.
-        Box::leak(b).into()
-    }
-
     #[unstable(
         feature = "ptr_internals",
         issue = "none",

library/alloc/src/fmt.rs

@@ -83,7 +83,7 @@
 //! # Formatting Parameters
 //!
 //! Each argument being formatted can be transformed by a number of formatting
-//! parameters (corresponding to `format_spec` in the syntax above). These
+//! parameters (corresponding to `format_spec` in [the syntax](#syntax)). These
 //! parameters affect the string representation of what's being formatted.
 //!
 //! ## Width

library/alloc/src/rc.rs

@@ -645,29 +645,6 @@ impl<T: ?Sized> Rc<T> {
         unsafe { Self::from_ptr(rc_ptr) }
     }
 
-    /// Consumes the `Rc`, returning the wrapped pointer as `NonNull<T>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(rc_into_raw_non_null)]
-    /// #![allow(deprecated)]
-    ///
-    /// use std::rc::Rc;
-    ///
-    /// let x = Rc::new("hello".to_owned());
-    /// let ptr = Rc::into_raw_non_null(x);
-    /// let deref = unsafe { ptr.as_ref() };
-    /// assert_eq!(deref, "hello");
-    /// ```
-    #[unstable(feature = "rc_into_raw_non_null", issue = "47336")]
-    #[rustc_deprecated(since = "1.44.0", reason = "use `Rc::into_raw` instead")]
-    #[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 allocation.
     ///
     /// [weak]: struct.Weak.html

library/alloc/src/string.rs

@@ -2196,6 +2196,9 @@ pub trait ToString {
 /// since `fmt::Write for String` never returns an error itself.
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: fmt::Display + ?Sized> ToString for T {
+    // A common guideline is to not inline generic functions. However,
+    // remove `#[inline]` from this method causes non-negligible regression.
+    // See <https://github.com/rust-lang/rust/pull/74852> as last attempt try to remove it.
     #[inline]
     default fn to_string(&self) -> String {
         use fmt::Write;

library/alloc/src/sync.rs

@@ -646,29 +646,6 @@ impl<T: ?Sized> Arc<T> {
         }
     }
 
-    /// Consumes the `Arc`, returning the wrapped pointer as `NonNull<T>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// #![feature(rc_into_raw_non_null)]
-    /// #![allow(deprecated)]
-    ///
-    /// use std::sync::Arc;
-    ///
-    /// let x = Arc::new("hello".to_owned());
-    /// let ptr = Arc::into_raw_non_null(x);
-    /// let deref = unsafe { ptr.as_ref() };
-    /// assert_eq!(deref, "hello");
-    /// ```
-    #[unstable(feature = "rc_into_raw_non_null", issue = "47336")]
-    #[rustc_deprecated(since = "1.44.0", reason = "use `Arc::into_raw` instead")]
-    #[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 allocation.
     ///
     /// [weak]: struct.Weak.html

library/core/src/sync/atomic.rs

@@ -2649,7 +2649,8 @@ unsafe fn atomic_umin<T: Copy>(dst: *mut T, val: T, order: Ordering) -> T {
 ///     }
 ///
 ///     pub fn lock(&self) {
-///         while !self.flag.compare_and_swap(false, true, Ordering::Relaxed) {}
+///         // Wait until the old value is `false`.
+///         while self.flag.compare_and_swap(false, true, Ordering::Relaxed) != false {}
 ///         // This fence synchronizes-with store in `unlock`.
 ///         fence(Ordering::Acquire);
 ///     }

library/std/src/net/ip.rs

@@ -1265,15 +1265,15 @@ impl Ipv6Addr {
     /// # See also
     ///
     /// - [IETF RFC 4291 section 2.5.6]
-    /// - [RFC 4291 errata 4406]
+    /// - [RFC 4291 errata 4406] (which has been rejected but provides useful
+    ///   insight)
     /// - [`is_unicast_link_local()`]
     ///
     /// [IETF RFC 4291]: https://tools.ietf.org/html/rfc4291
     /// [IETF RFC 4291 section 2.5.6]: https://tools.ietf.org/html/rfc4291#section-2.5.6
     /// [`true`]: ../../std/primitive.bool.html
     /// [RFC 4291 errata 4406]: https://www.rfc-editor.org/errata/eid4406
     /// [`is_unicast_link_local()`]: ../../std/net/struct.Ipv6Addr.html#method.is_unicast_link_local
-    ///
     pub fn is_unicast_link_local_strict(&self) -> bool {
         (self.segments()[0] & 0xffff) == 0xfe80
             && (self.segments()[1] & 0xffff) == 0
@@ -1324,13 +1324,13 @@ impl Ipv6Addr {
     /// # See also
     ///
     /// - [IETF RFC 4291 section 2.4]
-    /// - [RFC 4291 errata 4406]
+    /// - [RFC 4291 errata 4406] (which has been rejected but provides useful
+    ///   insight)
     ///
     /// [IETF RFC 4291 section 2.4]: https://tools.ietf.org/html/rfc4291#section-2.4
     /// [`true`]: ../../std/primitive.bool.html
     /// [RFC 4291 errata 4406]: https://www.rfc-editor.org/errata/eid4406
     /// [`is_unicast_link_local_strict()`]: ../../std/net/struct.Ipv6Addr.html#method.is_unicast_link_local_strict
-    ///
     pub fn is_unicast_link_local(&self) -> bool {
         (self.segments()[0] & 0xffc0) == 0xfe80
     }

src/doc/unstable-book/src/language-features/plugin.md

@@ -35,7 +35,7 @@ of a library.
 Plugins can extend [Rust's lint
 infrastructure](../../reference/attributes/diagnostics.md#lint-check-attributes) with
 additional checks for code style, safety, etc. Now let's write a plugin
-[`lint_plugin_test.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui-fulldeps/auxiliary/lint_plugin_test.rs)
+[`lint-plugin-test.rs`](https://github.com/rust-lang/rust/blob/master/src/test/ui-fulldeps/auxiliary/lint-plugin-test.rs)
 that warns about any item named `lintme`.
 
 ```rust,ignore

src/librustc_lint/unused.rs

@@ -203,6 +203,28 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                     // Otherwise, we don't lint, to avoid false positives.
                     _ => false,
                 },
+                ty::Closure(..) => {
+                    cx.struct_span_lint(UNUSED_MUST_USE, span, |lint| {
+                        let mut err = lint.build(&format!(
+                            "unused {}closure{}{} that must be used",
+                            descr_pre, plural_suffix, descr_post,
+                        ));
+                        err.note("closures are lazy and do nothing unless called");
+                        err.emit();
+                    });
+                    true
+                }
+                ty::Generator(..) => {
+                    cx.struct_span_lint(UNUSED_MUST_USE, span, |lint| {
+                        let mut err = lint.build(&format!(
+                            "unused {}generator{}{} that must be used",
+                            descr_pre, plural_suffix, descr_post,
+                        ));
+                        err.note("generators are lazy and do nothing unless resumed");
+                        err.emit();
+                    });
+                    true
+                }
                 _ => false,
             }
         }

src/librustc_symbol_mangling/v0.rs

@@ -636,9 +636,7 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
                 }
                 GenericArgKind::Const(c) => {
                     self.push("K");
-                    // FIXME(const_generics) implement `ty::print::Print` on `ty::Const`.
-                    // self = c.print(self)?;
-                    self = self.print_const(c)?;
+                    self = c.print(self)?;
                 }
             }
         }

src/librustc_target/spec/thumbv4t_none_eabi.rs

@@ -29,7 +29,7 @@ pub fn target() -> TargetResult {
          * native integers are 32-bit
          * All other elements are default
          */
-        data_layout: "e-S64-p:32:32-i64:64-m:e-n32".to_string(),
+        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".to_string(),
         linker_flavor: LinkerFlavor::Ld,
         options: TargetOptions {
             linker: Some("arm-none-eabi-ld".to_string()),

src/librustdoc/clean/auto_trait.rs

@@ -430,14 +430,14 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
     }
 
     // Converts the calculated ParamEnv and lifetime information to a clean::Generics, suitable for
-    // display on the docs page. Cleaning the Predicates produces sub-optimal WherePredicate's,
+    // display on the docs page. Cleaning the Predicates produces sub-optimal `WherePredicate`s,
     // so we fix them up:
     //
     // * Multiple bounds for the same type are coalesced into one: e.g., 'T: Copy', 'T: Debug'
     // becomes 'T: Copy + Debug'
     // * Fn bounds are handled specially - instead of leaving it as 'T: Fn(), <T as Fn::Output> =
     // K', we use the dedicated syntax 'T: Fn() -> K'
-    // * We explcitly add a '?Sized' bound if we didn't find any 'Sized' predicates for a type
+    // * We explicitly add a '?Sized' bound if we didn't find any 'Sized' predicates for a type
     fn param_env_to_generics(
         &self,
         tcx: TyCtxt<'tcx>,
@@ -588,7 +588,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                                         .args;
 
                                     match args {
-                                        // Convert somethiung like '<T as Iterator::Item> = u8'
+                                        // Convert something like '<T as Iterator::Item> = u8'
                                         // to 'T: Iterator<Item=u8>'
                                         GenericArgs::AngleBracketed {
                                             ref mut bindings, ..
@@ -712,7 +712,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
     // since FxHasher has different behavior for 32-bit and 64-bit platforms.
     //
     // Obviously, it's extremely undesirable for documentation rendering
-    // to be depndent on the platform it's run on. Apart from being confusing
+    // to be dependent on the platform it's run on. Apart from being confusing
     // to end users, it makes writing tests much more difficult, as predicates
     // can appear in any order in the final result.
     //

src/test/ui/generator/issue-52398.rs

@@ -14,14 +14,14 @@ impl A {
 fn main() {
     // Test that the MIR local with type &A created for the auto-borrow adjustment
     // is caught by typeck
-    move || {
+    move || { //~ WARN unused generator that must be used
         A.test(yield);
     };
 
     // Test that the std::cell::Ref temporary returned from the `borrow` call
     // is caught by typeck
     let y = RefCell::new(true);
-    static move || {
+    static move || { //~ WARN unused generator that must be used
         yield *y.borrow();
         return "Done";
     };

src/test/ui/generator/issue-52398.stderr

@@ -0,0 +1,24 @@
+warning: unused generator that must be used
+  --> $DIR/issue-52398.rs:17:5
+   |
+LL | /     move || {
+LL | |         A.test(yield);
+LL | |     };
+   | |______^
+   |
+   = note: `#[warn(unused_must_use)]` on by default
+   = note: generators are lazy and do nothing unless resumed
+
+warning: unused generator that must be used
+  --> $DIR/issue-52398.rs:24:5
+   |
+LL | /     static move || {
+LL | |         yield *y.borrow();
+LL | |         return "Done";
+LL | |     };
+   | |______^
+   |
+   = note: generators are lazy and do nothing unless resumed
+
+warning: 2 warnings emitted
+

src/test/ui/generator/issue-57084.rs

@@ -19,7 +19,7 @@ where F: Fn() -> ()
 
 fn main() {
     let data = &vec![1];
-    || {
+    || { //~ WARN unused generator that must be used
         let _to_pin = with(move || println!("{:p}", data));
         loop {
             yield

src/test/ui/generator/issue-57084.stderr

@@ -0,0 +1,16 @@
+warning: unused generator that must be used
+  --> $DIR/issue-57084.rs:22:5
+   |
+LL | /     || {
+LL | |         let _to_pin = with(move || println!("{:p}", data));
+LL | |         loop {
+LL | |             yield
+LL | |         }
+LL | |     };
+   | |______^
+   |
+   = note: `#[warn(unused_must_use)]` on by default
+   = note: generators are lazy and do nothing unless resumed
+
+warning: 1 warning emitted
+

src/test/ui/generator/match-bindings.rs

@@ -9,7 +9,7 @@ enum Enum {
 }
 
 fn main() {
-    || {
+    || { //~ WARN unused generator that must be used
         loop {
             if let true = true {
                 match Enum::A(String::new()) {

src/test/ui/generator/match-bindings.stderr

@@ -0,0 +1,17 @@
+warning: unused generator that must be used
+  --> $DIR/match-bindings.rs:12:5
+   |
+LL | /     || {
+LL | |         loop {
+LL | |             if let true = true {
+LL | |                 match Enum::A(String::new()) {
+...  |
+LL | |         }
+LL | |     };
+   | |______^
+   |
+   = note: `#[warn(unused_must_use)]` on by default
+   = note: generators are lazy and do nothing unless resumed
+
+warning: 1 warning emitted
+

src/test/ui/generator/reborrow-mut-upvar.rs

@@ -3,7 +3,7 @@
 #![feature(generators)]
 
 fn _run(bar: &mut i32) {
-    || {
+    || { //~ WARN unused generator that must be used
         {
             let _baz = &*bar;
             yield;

src/test/ui/generator/reborrow-mut-upvar.stderr

@@ -0,0 +1,17 @@
+warning: unused generator that must be used
+  --> $DIR/reborrow-mut-upvar.rs:6:5
+   |
+LL | /     || {
+LL | |         {
+LL | |             let _baz = &*bar;
+LL | |             yield;
+...  |
+LL | |         *bar = 2;
+LL | |     };
+   | |______^
+   |
+   = note: `#[warn(unused_must_use)]` on by default
+   = note: generators are lazy and do nothing unless resumed
+
+warning: 1 warning emitted
+