Cleanup rustc/middle

[ljedrz]

• improve allocations
• use Cow<'static, str> where applicable
• improve some patterns
• whitespace & formatting fixes

[rust-highfive]

r? @michaelwoerister

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[bors]

☔ The latest upstream changes (presumably #54767) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-highfive]

The job x86_64-gnu-llvm-5.0 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.

[00:07:46] 
[00:07:46] error[E0614]: type `syntax_pos::Span` cannot be dereferenced
[00:07:46]     --> librustc/middle/resolve_lifetime.rs:1109:22
[00:07:46]      |
[00:07:46] 1109 |         ).span_label(*explicit_span, "explicit lifetime definition here")
[00:07:46] 
[00:07:54] error: aborting due to 3 previous errors
[00:07:54] 
[00:07:54] For more information about this error, try `rustc --explain E0614`.
[00:07:54] For more information about this error, try `rustc --explain E0614`.
[00:07:54] error: Could not compile `rustc`.
[00:07:54] 
[00:07:54] To learn more, run the command again with --verbose.
[00:07:54] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "-j" "4" "--release" "--locked" "--color" "always" "--features" " jemalloc" "--manifest-path" "/checkout/src/rustc/Cargo.toml" "--message-format" "json"
[00:07:54] expected success, got: exit code: 101
[00:07:54] thread 'main' panicked at 'cargo must succeed', bootstrap/compile.rs:1112:9
[00:07:54] travis_fold:end:stage0-rustc

[00:07:54] travis_time:end:stage0-rustc:start=1538561089982951430,finish=1538561248173324841,duration=158190373411


[00:07:54] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap build
[00:07:54] Build completed unsuccessfully in 0:03:31
[00:07:54] Makefile:28: recipe for target 'all' failed
[00:07:54] make: *** [all] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:0b440822
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)

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)

[ljedrz]

Rebased.

[ljedrz]

It seems @michaelwoerister might be currently unavailable;

r? @zackmdavis

[zackmdavis]

(I'll take a look Friday evening.)

[michaelwoerister]

This looks a bit problematic. From the code it's not entirely clear if the second find will see any elements, since they might have been consumed by the first find. I'd just leave this as is.

[ljedrz]

Ah, you're right; I'll fix it shortly.

[ljedrz]

@michaelwoerister thanks, issue addressed.

[michaelwoerister]

Thanks! @bors r+

[bors]

📌 Commit 97d37ed8a89c40aaca429c3b73b22cae70164722 has been approved by michaelwoerister

[bors]

☔ The latest upstream changes (presumably #54741) made this pull request unmergeable. Please resolve the merge conflicts.

[ljedrz]

Rebased.

[michaelwoerister]

@bors r+

[bors]

📌 Commit 786b86e has been approved by michaelwoerister

[bors]

⌛ Testing commit 786b86e with merge 4efdc04...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: michaelwoerister
Pushing 4efdc04 to master...