Stabilize edition 2018; also updates Clippy, RLS and Cargo

[matthiaskrgr]

Supersedes #53999 , #53935
Clippy build was failing there because crate_visibility_modifier feature was taken out of edition 2018 and clippy used it.
The clippy update enables the corresponding feature explicitly.

r? @Mark-Simulacrum

[rust-highfive]

⚠️ Warning ⚠️

• These commits modify submodules.

[matthiaskrgr]

Urgh, looks like rls needs to be fixed as well....

[Mark-Simulacrum]

@bors r=alexcrichton (carrying over approval from #53999)

[bors]

📌 Commit 3e56dec has been approved by alexcrichton

[Mark-Simulacrum]

@bors p=5

[bors]

⌛ Testing commit 3e56dec with merge 3e3d86293d705ef7e3393b4babcfb292d98b293f...

[bors]

💔 Test failed - status-appveyor

[matthiaskrgr]

Looks like rls fails to build..?

   --> tools\rls\src\build\plan.rs:189:80
    |
189 |                 *target.kind() == TargetKind::CustomBuild && target.src_path().is_path()
    |                                                                                ^^^^^^^
error[E0599]: no method named `path` found for type `&std::path::Path` in the current scope
   --> tools\rls\src\build\plan.rs:191:56
    |
191 |             .map(|(key, unit)| (unit.target.src_path().path(), key.clone()))
    |                                                        ^^^^
error[E0599]: no method named `path` found for type `&std::path::Path` in the current scope
   --> tools\rls\src\build\plan.rs:202:26
    |
202 |                         .path()
    |                          ^^^^
error[E0599]: no method named `path` found for type `&std::path::Path` in the current scope
  --> tools\rls\src\project_model.rs:82:44
   |
82 |                     .map(|t| (t.src_path().path().to_owned(), t.name().replace('-', "_"))),
   |                                            ^^^^
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0599`.
[RUSTC-TIMING] rls test:false 4.825
error: Could not compile `rls`.

[ehuss]

@matthiaskrgr I think #53935 needs to be merged first.

[matthiaskrgr]

@ehuss Hm, why?

[ehuss]

RLS requires the update to Cargo (due to rust-lang/rls#1048), and Cargo requires the update to RLS (since RLS is not allowed to be broken).

[matthiaskrgr]

Uff....
I might have to try pulling in a cargo update into this PR then..

[matthiaskrgr]

@ehuss I tried merging the cargo changes of 53953 now.

[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.

[00:05:32] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:05:33] tidy error: /checkout/src/bootstrap/test.rs:242: trailing whitespace
[00:05:34] some tidy checks failed
[00:05:34] 
[00:05:34] 
[00:05:34] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor" "--quiet"
[00:05:34] 
[00:05:34] 
[00:05:34] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:05:34] Build completed unsuccessfully in 0:00:54
[00:05:34] Build completed unsuccessfully in 0:00:54
[00:05:34] Makefile:79: recipe for target 'tidy' failed
[00:05:34] make: *** [tidy] Error 1

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:128eefce
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
---
travis_time:end:0aeb74b0:start=1536488984423324351,finish=1536488984429906725,duration=6582374
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:018c6f44
$ 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 -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:04ad16ce
travis_time:start:04ad16ce
$ 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:1eb2d2e3
$ 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)

[ehuss]

@ehuss I tried merging the cargo changes of 53953 now.

👍 hopefully this can get through the queue before tuesday 😄

[Mark-Simulacrum]

@bors r+ p=5

[bors]

📌 Commit 60be068 has been approved by Mark-Simulacrum

[bors]

⌛ Testing commit 60be068 with merge f50b775...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: Mark-Simulacrum
Pushing f50b775 to master...