Add match arm scopes and other scope fixes #60174

matthewjasper · 2019-04-22T16:53:35Z

Add drop and lint scopes for match arms.
Lint attributes are now respected on match arms.
Make sure we emit a StorageDead if we diverge when initializing a temporary.
Adjust MIR pretty printing of scopes for locals.
Don't generate duplicate lint scopes for let statements.
Add some previously missing fake borrows for matches.

closes #46525

cc @rust-lang/compiler

rust-highfive · 2019-04-22T16:53:39Z

r? @eddyb

(rust_highfive has picked a reviewer for you, use r? to override)

matthewjasper · 2019-04-22T16:55:27Z

@bors try

This probably should be cratered because it breaks code uses #[deny(...)] on a match arm and then does the thing that was denied. This seems unlikely.
This also probably needs a perf run.

bors · 2019-04-22T16:55:38Z

⌛ Trying commit 2feb6385c62f996092c3883f26918aa9af810fe4 with merge 49a98abd081547c1b12687ed2ca0de70f8d72029...

src/librustc/cfg/construct.rs

src/librustc_mir/build/expr/as_temp.rs

src/librustc_mir/build/scope.rs

src/librustc_mir/dataflow/impls/mod.rs

Centril · 2019-04-22T18:08:29Z

Add drop and lint scopes for match arms.

Lint attributes are now respected on match arms.

Seems right, but cc @rust-lang/lang

eddyb · 2019-04-23T10:34:40Z

@matthewjasper I just rebased #56278, can you check if your PR breaks anything I want to enforce in that PR?
Also, feel free to review it, if you have the time.

matthewjasper · 2019-04-23T20:41:35Z

@eddyb It looks like there shouldn't be any problems there.

bors · 2019-04-24T06:20:01Z

☔ The latest upstream changes (presumably #60224) made this pull request unmergeable. Please resolve the merge conflicts.

matthewjasper · 2019-04-24T20:36:38Z

@bors try

bors · 2019-04-24T20:36:49Z

⌛ Trying commit a510e30ca8310916760e246847b0be13db4ce844 with merge 74092351c05ae61047b2be02024415546595e974...

bors · 2019-04-24T22:58:28Z

☀️ Try build successful - checks-travis
Build commit: 74092351c05ae61047b2be02024415546595e974

estebank · 2019-04-24T23:16:48Z

@craterbot run start=master#e305df1846a6d985315917ae0c81b74af8b4e641 end=try#74092351c05ae61047b2be02024415546595e974 mode=check-only

craterbot · 2019-04-24T23:16:50Z

👌 Experiment pr-60174 created and queued.
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2019-04-24T23:16:54Z

🚧 Experiment pr-60174 is now running on agent aws-3-tmp.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

estebank · 2019-04-24T23:18:57Z

@rust-timer build 74092351c05ae61047b2be02024415546595e974

rust-timer · 2019-04-24T23:18:59Z

Success: Queued 74092351c05ae61047b2be02024415546595e974 with parent e305df1, comparison URL.

rust-timer · 2019-04-25T05:45:17Z

Finished benchmarking try commit 74092351c05ae61047b2be02024415546595e974

craterbot · 2019-04-26T12:58:14Z

🎉 Experiment pr-60174 is completed!
📊 0 regressed and 0 fixed (60951 total)
📰 Open the full report.

⚠️ If you notice any spurious failure please add them to the blacklist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

* Don't generate an extra lint scope for each `let` statement. * Place match guards inside the visiblility scope of the bindings for their arm.

Also give arms the correct lint scope in MIR.

I was incorrectly under the impression that this would only lead to duplicates. See `mir-opt/match-arm-scope.rs` (upcomming commit) for a case where we didn't emit a fake borrow of `items.1`.

This ensures that we will correctly generate a storage-dead if the initializing expression diverges.

Co-Authored-By: matthewjasper <mjjasper1@gmail.com>

matthewjasper · 2019-05-22T05:01:33Z

@bors r=pnkfelix

bors · 2019-05-22T05:01:35Z

📌 Commit 0835048 has been approved by pnkfelix

bors · 2019-05-22T11:08:34Z

⌛ Testing commit 0835048 with merge 79e50518a01ed5b42b0beb321f95c39311ae54b5...

pietroalbini · 2019-05-22T11:11:31Z

@bors retry

Yielding priority to beta.

bors · 2019-05-22T12:56:24Z

⌛ Testing commit 0835048 with merge 11f75e1080e60a8130dfecf39aa89935921892cf...

pietroalbini · 2019-05-22T13:30:37Z

@bors retry

bors · 2019-05-22T13:44:49Z

⌛ Testing commit 0835048 with merge 6f77e237130fe0e7b2c73aa930f778aa9d4081cd...

pietroalbini · 2019-05-22T13:49:02Z

@bors retry

rust-highfive · 2019-05-22T13:50:21Z

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.

Cloning into 'rust-lang/rust'...
travis_time:end:2d17cc3a:start=1558532963031480524,finish=1558532969010004454,duration=5978523930
$ cd rust-lang/rust
$ git checkout -qf 6f77e237130fe0e7b2c73aa930f778aa9d4081cd
fatal: reference is not a tree: 6f77e237130fe0e7b2c73aa930f778aa9d4081cd
The command "git checkout -qf 6f77e237130fe0e7b2c73aa930f778aa9d4081cd" failed and exited with 128 during .
Your build has been stopped.

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)

bors · 2019-05-23T04:48:29Z

⌛ Testing commit 0835048 with merge 85334c5...

Add match arm scopes and other scope fixes * Add drop and lint scopes for match arms. * Lint attributes are now respected on match arms. * Make sure we emit a StorageDead if we diverge when initializing a temporary. * Adjust MIR pretty printing of scopes for locals. * Don't generate duplicate lint scopes for `let statements`. * Add some previously missing fake borrows for matches. closes #46525 cc @rust-lang/compiler

bors · 2019-05-23T07:31:15Z

☀️ Test successful - checks-travis, status-appveyor
Approved by: pnkfelix
Pushing 85334c5 to master...

rust-highfive assigned eddyb Apr 22, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Apr 22, 2019

Centril reviewed Apr 22, 2019

View reviewed changes

matthewjasper force-pushed the add-match-arm-scopes branch 2 times, most recently from 5a387e2 to a8a9153 Compare April 22, 2019 18:38

matthewjasper force-pushed the add-match-arm-scopes branch from a8a9153 to a510e30 Compare April 24, 2019 18:36

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 24, 2019

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels Apr 26, 2019

matthewjasper force-pushed the add-match-arm-scopes branch from a510e30 to cba3e8e Compare April 30, 2019 20:52

matthewjasper and others added 9 commits May 21, 2019 19:37

Respect lint attributes on match arms

e784595

Handle the visibility/lint scope distinction better

af6a9a2

* Don't generate an extra lint scope for each `let` statement. * Place match guards inside the visiblility scope of the bindings for their arm.

Give match arms a drop/region scope

f506aea

Also give arms the correct lint scope in MIR.

Remove MIR borrowck hack for old match scopes

0f50724

Emit fake borrows for all tests

b5643f1

I was incorrectly under the impression that this would only lead to duplicates. See `mir-opt/match-arm-scope.rs` (upcomming commit) for a case where we didn't emit a fake borrow of `items.1`.

Schedule storage-dead of temporaries sooner

abab9ef

This ensures that we will correctly generate a storage-dead if the initializing expression diverges.

Add a test for match scopes

2420d82

Comment style fixes

015a451

Co-Authored-By: matthewjasper <mjjasper1@gmail.com>

Fix match ergonomics suggestion

0835048

matthewjasper force-pushed the add-match-arm-scopes branch from 5b5255d to 0835048 Compare May 21, 2019 19:35

bors added the merged-by-bors This PR was explicitly merged by bors. label May 23, 2019

bors merged commit 0835048 into rust-lang:master May 23, 2019

matthewjasper deleted the add-match-arm-scopes branch May 24, 2019 22:10

lqd mentioned this pull request Jun 28, 2019

ICE with borrow checker in nightly #62107

Closed

ehuss mentioned this pull request Jul 5, 2020

Strange span in borrow error in nested match. #74050

Closed

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Add match arm scopes and other scope fixes #60174

Add match arm scopes and other scope fixes #60174

matthewjasper commented Apr 22, 2019

rust-highfive commented Apr 22, 2019

matthewjasper commented Apr 22, 2019

bors commented Apr 22, 2019

Centril commented Apr 22, 2019

eddyb commented Apr 23, 2019

matthewjasper commented Apr 23, 2019

bors commented Apr 24, 2019

matthewjasper commented Apr 24, 2019

bors commented Apr 24, 2019

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matthewjasper commented May 22, 2019

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rust-highfive commented May 22, 2019

bors commented May 23, 2019

bors commented May 23, 2019

Add match arm scopes and other scope fixes #60174

Add match arm scopes and other scope fixes #60174

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matthewjasper commented Apr 22, 2019

rust-highfive commented Apr 22, 2019

matthewjasper commented Apr 22, 2019

bors commented Apr 22, 2019

Centril commented Apr 22, 2019

eddyb commented Apr 23, 2019

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bors commented Apr 24, 2019

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