Rename rustc_errors dependency in rust 2018 crates

[taiki-e]

I think this is a better solution than use rustc_errors as errors in lib.rs and use crate::errors in modules.

Related: rust-lang/cargo#5653

cc #58099

r? @Centril

[Centril]

r? @matthewjasper

[matthewjasper]

Can these be moved down to the other external dependencies?

[bors]

☔ The latest upstream changes (presumably #57617) made this pull request unmergeable. Please resolve the merge conflicts.

[bors]

☔ The latest upstream changes (presumably #57770) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:103a7cf0:start=1549778314219868599,finish=1549778316582096125,duration=2362227526
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
Setting environment variables from .travis.yml
$ export IMAGE=x86_64-gnu-llvm-6.0
---
[00:19:12]    Compiling rustc_codegen_utils v0.0.0 (/checkout/src/librustc_codegen_utils)
[00:19:12] error[E0432]: unresolved import `crate::errors`
[00:19:12]   --> src/librustc_resolve/error_reporting.rs:12:12
[00:19:12]    |
[00:19:12] 12 | use crate::errors::{Applicability, DiagnosticBuilder, DiagnosticId};
[00:19:12]    |            ^^^^^^ did you mean `syntax::errors`?
[00:19:14] error: aborting due to previous error
[00:19:14] 
[00:19:14] For more information about this error, try `rustc --explain E0432`.
[00:19:14] error: Could not compile `rustc_resolve`.
---
travis_time:end:02f80ad6:start=1549779531477024746,finish=1549779531483289639,duration=6264893
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0d1dcac0
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:15166d90
travis_time:start:15166d90
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:0b9f5878
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[petrochenkov]

@taiki-e

I think this is a better solution than use rustc_errors as errors in lib.rs and use crate::errors in modules.

FWIW, you don't need use crate::errors, extern crate rustc_errors as errors + use errors would work as well.
Cargo.toml is still the more idiomatic solution though.

[matthewjasper]

@bors r+

[bors]

📌 Commit 8bb7f5f21c5cf3877ea9b9404b3ba400f113c116 has been approved by matthewjasper

[taiki-e]

@petrochenkov

FWIW, you don't need use crate::errors, extern crate rustc_errors as errors + use errors would work as well.

Yeah, we originally used extern crate rustc_errors as errors + use errors. But changed this to use rustc_errors as errors + use crate::errors based on unused_extern_crates(included in rust_2018_idioms)'s message.
(And I remembered that there was a way not requiring #[allow(unused_extern_crates)] or use crate::errors after they were merged, so I wrote this PR.)

[bors]

☔ The latest upstream changes (presumably #58151) made this pull request unmergeable. Please resolve the merge conflicts.

[taiki-e]

Rebased.

r? @matthewjasper

[bors]

☔ The latest upstream changes (presumably #58098) made this pull request unmergeable. Please resolve the merge conflicts.

[taiki-e]

Rebased.

[matthewjasper]

@bors r+

[bors]

📌 Commit c08b5ca has been approved by matthewjasper