introduce type-op for user-type ascription in NLL

[nikomatsakis]

Handle user-type ascription in a type operator, which gives us a lot more flexibility around the order in which we resolve things.

r? @pnkfelix

Fixes #55219
Fixes #55241

[pnkfelix]

@bors r+ p=1

I’ve gotta rebase stuff (namely #55274) atop this so I’m giving it high priority so I can be more confident such rebasing will go through cleanly

[bors]

📌 Commit 05a9b1197860849ff95370e56c0e6c74b2f111ee has been approved by pnkfelix

[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.

travis_time:end:01ae2bf7:start=1540406309533525138,finish=1540406310565516447,duration=1031991309
$ 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 SCCACHE_BUCKET=rust-lang-ci-sccache2
---

[00:03:52] travis_fold:start:tidy
travis_time:start:tidy
tidy check
[00:03:52] tidy error: /checkout/src/librustc/dep_graph/dep_node.rs:75: line longer than 100 chars
[00:03:52] tidy error: /checkout/src/librustc/ty/query/config.rs:17: line longer than 100 chars
[00:03:52] tidy error: /checkout/src/librustc/ty/query/config.rs:119: line longer than 100 chars
[00:03:52] tidy error: /checkout/src/librustc/ty/query/mod.rs:38: line longer than 100 chars
[00:03:54] some tidy checks failed
[00:03:54] 
[00:03:54] 
[00:03:54] 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"
[00:03:54] 
[00:03:54] 
[00:03:54] failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
[00:03:54] Build completed unsuccessfully in 0:00:47
[00:03:54] Build completed unsuccessfully in 0:00:47
[00:03:54] make: *** [tidy] Error 1
[00:03:54] Makefile:79: recipe for target 'tidy' failed

The command "stamp sh -x -c "$RUN_SCRIPT"" exited with 2.
travis_time:start:089c81f8
$ date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
---
travis_time:end:0cfce460:start=1540406556926874937,finish=1540406556931185348,duration=4310411
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:13d2b9f1
$ 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:02274316
travis_time:start:02274316
$ 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:101c0f40
$ 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)

[TimNN]

@bors r-

Fails tidy.

[nikomatsakis]

@bors r=pnkfelix

Passes x.py test locally (at least up until the gdb tests, which are broken for me for unrelated reasons)

[bors]

📌 Commit 62f0fc5 has been approved by pnkfelix

[bors]

💡 This pull request was already approved, no need to approve it again.

• There's another pull request that is currently being tested, blocking this pull request: Stable release 1.30 #55315

[bors]

📌 Commit 62f0fc5 has been approved by pnkfelix

[bors]

⌛ Testing commit 62f0fc5 with merge 39a47b87f47f5eb044778fd6c3ba77cdba5b8078...

[bors]

💥 Test timed out

[kennytm]

@bors retry

AppVeyor got stuck and not responding.

[bors]

⌛ Testing commit 62f0fc5 with merge 3476ac0...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: pnkfelix
Pushing 3476ac0 to master...