ICE - Unprintable span

[thepowersgang]

Encountered using heavy-duty macro abuse and reproduced on current nightly.

https://travis-ci.org/thepowersgang/rust_os/builds/120407504#L340

Code being built:
https://github.com/thepowersgang/rust_os/blob/20160403_ice_unprintable/Usermode/libsyscalls/

(Sorry for the lacklustre report, I will attempt to reduce to a testcase in a few hours)

[thepowersgang]

Smaller reproduction - https://gist.github.com/thepowersgang/fc6170c10aa11347104ce54cafb124d0, Doesn't appear on playpen so is likely related to the multiple-file structure

[thepowersgang]

Fully reduced to under 30 lines. The error appears when the macro invocation is in a different file to the definition.

lib.rs:6:9: 3:23 error: unresolved name `values::VFS_OPENNODE` [E0425]
(internal compiler error: unprintable span)
vfs.rs:3:2: 3:25 note: in this expansion of syscall! (defined in lib.rs)
lib.rs:6:9: 3:23 help: run `rustc --explain E0425` to see a detailed explanation
error: aborting due to previous error

When the invocation is moved into lib.rs (still in the vfs module) a span is printed (but not a very good one)

[durka]

Some older unprintable spans @ #31719. Doesn't seem very related though.

[tiehuis]

Just ran into something similar. This may be related (may not, but involves some macro use as in the first). Here is the simplified test case in this example.

https://gist.github.com/tiehuis/2000a3e1a3e2cfdd031208863b75f9f5

This generates an error on a single file which appears slightly different to the previous example. Fails on the playpen nightly branch.

rustc --version --verbose
rustc 1.9.0-nightly (177905703 2016-04-08)
binary: rustc
commit-hash: 17790570373a7f560950d53ea4d67807232db255
commit-date: 2016-04-08
host: x86_64-unknown-linux-gnu
release: 1.9.0-nightly

And the error in question:

rustup run nightly rustc main.rs
main.rs:11:6: 6:19 error: mismatched types:
 expected `&'static Bar`,
    found `Bar`
(expected &-ptr,
    found struct `Bar`) [E0308]
(internal compiler error: unprintable span)
main.rs:11:1: 11:11 note: in this expansion of foo! (defined in main.rs)
main.rs:11:6: 6:19 help: run `rustc --explain E0308` to see a detailed explanation

[Mark-Simulacrum]

No longer ICEs.

error[E0425]: cannot find value `VFS_OPENNODE` in module `values`
 --> ./vfs.rs:3:11
  |
3 | 	syscall!(VFS_OPENNODE);
  | 	         ^^^^^^^^^^^^ not found in `values`

error: aborting due to previous error