Add CoerceShared field-wise reborrow WF checks by P8L1 · Pull Request #157489 · rust-lang/rust

P8L1 · 2026-06-05T16:28:43Z

This PR attempts to add a well-formedness check for CoerceShared.
Split out of #157101

P8L1 · 2026-06-05T16:29:09Z

@rustbot label +F-Reborrow

aapoalas

Some issues but overall this looks pretty promising.

I'd kind of like the tests to all rather be added in the #157490 and then this PR to show which ones it fixes and which ones remain issues, but I'm not too partial on that point. I've reviewed the PR in the conventional comments style, so anything marked "thought" or "note" is just musings and not something you need to necessarily react to (unless you wish to), "question" is me being unsure but not something that would block the PR from merging, and "issues" and anything else marked "blocking" must be addressed before this can be considered for merging.

I'm also somewhat surprised that this PR didn't actually change any of the existing test results... I guess that's just a sign of our existing ui feature tests being insufficient :D

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rustbot · 2026-06-05T19:18:14Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

P8L1 · 2026-06-08T14:27:34Z

@rustbot ready

aapoalas

Two issues remain from my point of view. I'll pass this for compiler reviewers next :)

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P8L1 · 2026-06-12T11:19:55Z

@rustbot ready

P8L1 · 2026-06-14T21:14:14Z

I will be rebasing this Wednesday I think, and I will also update it so it shows what tests it fixes

P8L1 · 2026-06-15T10:03:57Z

Ok, I had some time sooner than I expected I would. @aapoalas, I think I'm ready for another review.

aapoalas · 2026-06-15T10:16:33Z

r? @oli-obk

oli-obk

One more nit, lgtm now.

Please squash the commits appropriately. I'm fine with one big one, but if you have sth more fine grained that wfm

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Localize the WF helper logic to builtin coherence and add the directly related UI coverage.

rustbot · 2026-07-10T22:08:24Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

P8L1 · 2026-07-10T22:44:30Z

@rustbot ready

P8L1 · 2026-07-22T12:20:45Z

@oli-obk Hi, I'm sorry to ping you, but could you please take a look at this when you get the chance. It has been about 2 weeks.

oli-obk · 2026-08-05T15:06:42Z

I kept seeing it on my review queue. I'm sorry, I should have reviewed it immediately.

@bors r+ rollup

rust-bors · 2026-08-05T15:06:45Z

📌 Commit ec4384c has been approved by oli-obk

It is now in the queue for this repository.

P8L1 · 2026-08-05T16:57:59Z

I kept seeing it on my review queue. I'm sorry, I should have reviewed it immediately.

@bors r+ rollup

It's fine, I'm sure you have more than enough on your plate already.

Thanks so much for your review!

…uwer Rollup of 12 pull requests Successful merges: - #159014 ([rustdoc] Do not take `doc(cfg())` into account when filtering doctests) - #159029 (rustc_llvm: Emit module summaries when using -Clto=fat) - #160574 (Update rustc-perf submodule) - #154585 (treat no_mangle_generic_items as hard error instead of lint warning) - #159473 (Fix, simplify, and document doc meta finalize mode) - #157489 (Add CoerceShared field-wise reborrow WF checks) - #160532 (Add Enzyme bugfix to support rust+llvm23) - #160545 (Reorder the methods in `#[rustc_must_implement_one_of]`) - #160558 (Revert "codegen_ssa: no dbginfo for scalable vec local w/ `-O0`") - #160566 (Re-enable bool indexing assembly test for LLVM 23) - #160569 (Remove `OnDuplicate::Custom`) - #160576 ([rustdoc] Create output file after we checked that the standalone markdown file is valid)

@aapoalas

Rollup merge of #157489 - P8L1:split/coerceshared-wf-check, r=oli-obk Add CoerceShared field-wise reborrow WF checks This PR attempts to add a well-formedness check for CoerceShared. Split out of #157101 r? @aapoalas

…uwer Rollup of 12 pull requests Successful merges: - rust-lang/rust#159014 ([rustdoc] Do not take `doc(cfg())` into account when filtering doctests) - rust-lang/rust#159029 (rustc_llvm: Emit module summaries when using -Clto=fat) - rust-lang/rust#160574 (Update rustc-perf submodule) - rust-lang/rust#154585 (treat no_mangle_generic_items as hard error instead of lint warning) - rust-lang/rust#159473 (Fix, simplify, and document doc meta finalize mode) - rust-lang/rust#157489 (Add CoerceShared field-wise reborrow WF checks) - rust-lang/rust#160532 (Add Enzyme bugfix to support rust+llvm23) - rust-lang/rust#160545 (Reorder the methods in `#[rustc_must_implement_one_of]`) - rust-lang/rust#160558 (Revert "codegen_ssa: no dbginfo for scalable vec local w/ `-O0`") - rust-lang/rust#160566 (Re-enable bool indexing assembly test for LLVM 23) - rust-lang/rust#160569 (Remove `OnDuplicate::Custom`) - rust-lang/rust#160576 ([rustdoc] Create output file after we checked that the standalone markdown file is valid)

rustbot assigned aapoalas Jun 5, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 5, 2026

rustbot added the F-reborrow `#![feature(reborrow)]`; see #145612 label Jun 5, 2026

P8L1 mentioned this pull request Jun 5, 2026

Support field-wise CoerceShared reborrows #157101

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aapoalas requested changes Jun 5, 2026

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P8L1 requested a review from aapoalas June 8, 2026 14:27

aapoalas requested changes Jun 11, 2026

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P8L1 force-pushed the split/coerceshared-wf-check branch from c82f18a to 8a5f5aa Compare June 12, 2026 11:04

P8L1 requested a review from aapoalas June 12, 2026 11:19

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P8L1 force-pushed the split/coerceshared-wf-check branch from 46b362c to d5e890a Compare June 15, 2026 09:25

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rustbot assigned oli-obk and unassigned aapoalas Jun 15, 2026

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P8L1 requested a review from oli-obk July 9, 2026 23:15

oli-obk requested changes Jul 10, 2026

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Comment thread compiler/rustc_hir_analysis/src/coherence/builtin/coerce_shared.rs

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 10, 2026

P8L1 force-pushed the split/coerceshared-wf-check branch from ee0fb99 to 1300328 Compare July 10, 2026 20:55

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P8L1 added 3 commits July 10, 2026 23:41

Add CoerceShared field-wise reborrow WF checks

9eb0ddf

Localize the WF helper logic to builtin coherence and add the directly related UI coverage.

Check omitted CoerceShared ZST fields

674a342

Resolve CoerceShared field region obligations

ec4384c

P8L1 force-pushed the split/coerceshared-wf-check branch from 1300328 to ec4384c Compare July 10, 2026 22:08

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 10, 2026

P8L1 requested a review from oli-obk July 10, 2026 22:44

rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 5, 2026

JonathanBrouwer mentioned this pull request Aug 5, 2026

Rollup of 12 pull requests #160586

Merged

rust-bors Bot merged commit 7dbc6af into rust-lang:main Aug 6, 2026
13 checks passed

rustbot added this to the 1.99.0 milestone Aug 6, 2026

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