Ignore but do not assume region obligations from unifying headers in negative coherence by compiler-errors · Pull Request #117994 · rust-lang/rust

compiler-errors · 2023-11-16T22:56:05Z

Partly addresses a FIXME that was added in #112875. Just as we can throw away the nested trait/projection obligations from unifying two impl headers, we can also just throw away the region obligations too.

I removed part of the FIXME that was incorrect, namely:

Given that the only region constraints we get are involving inference regions in the root, it shouldn't matter, but still sus.

This is not true when unifying fn(A) and for<'b> fn(&'b B) which ends up with placeholder region outlives from non-root universes. I'm pretty sure this is okay, though it would be nice if we were to use them as assumptions. See the explicit revision of the test I committed, which still fails.

Fixes #117986

r? lcnr, feel free to reassign tho.

lcnr · 2023-11-17T09:15:30Z

@bors r+ rollup

bors · 2023-11-17T09:15:33Z

📌 Commit d688b86 has been approved by lcnr

It is now in the queue for this repository.

…-in-coherence, r=lcnr Ignore but do not assume region obligations from unifying headers in negative coherence Partly addresses a FIXME that was added in rust-lang#112875. Just as we can throw away the nested trait/projection obligations from unifying two impl headers, we can also just throw away the region obligations too. I removed part of the FIXME that was incorrect, namely: > Given that the only region constraints we get are involving inference regions in the root, it shouldn't matter, but still sus. This is not true when unifying `fn(A)` and `for<'b> fn(&'b B)` which ends up with placeholder region outlives from non-root universes. I'm pretty sure this is okay, though it would be nice if we were to use them as assumptions. See the `explicit` revision of the test I committed, which still fails. Fixes rust-lang#117986 r? lcnr, feel free to reassign tho.

TaKO8Ki · 2023-11-18T19:47:29Z

This pull request may have caused this error.

#118041 (comment)

compiler-errors · 2023-11-18T19:48:49Z

This PR conflicts with #117992. I will re-approve and land each separately, I think.

@bors r-

aliemjay · 2023-11-19T03:35:01Z

compiler/rustc_trait_selection/src/traits/coherence.rs

+    let _ = infcx.take_registered_region_obligations();
+    let _ = infcx.take_and_reset_region_constraints();


I think it would more more clear if they are explicitly dropped along with equate_obligations before forking in impl_intersection_has_negative_obligation.

drop(equate_obligations); drop(infcx.take_registered_region_obligations()); drop(infcx.take_and_reset_region_constraints());

…negative coherence

compiler-errors · 2023-11-19T19:35:42Z

@bors r=lcnr

Updated to use drop explicitly, and to drop the region obligations only once.

bors · 2023-11-19T19:35:45Z

📌 Commit 488dcb7 has been approved by lcnr

It is now in the queue for this repository.

…-in-coherence, r=lcnr Ignore but do not assume region obligations from unifying headers in negative coherence Partly addresses a FIXME that was added in rust-lang#112875. Just as we can throw away the nested trait/projection obligations from unifying two impl headers, we can also just throw away the region obligations too. I removed part of the FIXME that was incorrect, namely: > Given that the only region constraints we get are involving inference regions in the root, it shouldn't matter, but still sus. This is not true when unifying `fn(A)` and `for<'b> fn(&'b B)` which ends up with placeholder region outlives from non-root universes. I'm pretty sure this is okay, though it would be nice if we were to use them as assumptions. See the `explicit` revision of the test I committed, which still fails. Fixes rust-lang#117986 r? lcnr, feel free to reassign tho.

…mpiler-errors Rollup of 8 pull requests Successful merges: - rust-lang#115526 (Add arm64e-apple-ios & arm64e-apple-darwin targets) - rust-lang#115691 (Add `$message_type` field to distinguish json diagnostic outputs) - rust-lang#117828 (Avoid iterating over hashmaps in astconv) - rust-lang#117832 (interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch) - rust-lang#117891 (Recover `dyn` and `impl` after `for<...>`) - rust-lang#117957 (if available use a Child's pidfd for kill/wait) - rust-lang#117994 (Ignore but do not assume region obligations from unifying headers in negative coherence) - rust-lang#118068 (subtree update cg_gcc 2023/11/17) r? `@ghost` `@rustbot` modify labels: rollup

…mpiler-errors Rollup of 8 pull requests Successful merges: - rust-lang#117828 (Avoid iterating over hashmaps in astconv) - rust-lang#117832 (interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch) - rust-lang#117891 (Recover `dyn` and `impl` after `for<...>`) - rust-lang#117957 (if available use a Child's pidfd for kill/wait) - rust-lang#117988 (Handle attempts to have multiple `cfg`d tail expressions) - rust-lang#117994 (Ignore but do not assume region obligations from unifying headers in negative coherence) - rust-lang#118000 (Make regionck care about placeholders in outlives components) - rust-lang#118068 (subtree update cg_gcc 2023/11/17) r? `@ghost` `@rustbot` modify labels: rollup

…tthiaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#117828 (Avoid iterating over hashmaps in astconv) - rust-lang#117832 (interpret: simplify handling of shifts by no longer trying to handle signed and unsigned shift amounts in the same branch) - rust-lang#117891 (Recover `dyn` and `impl` after `for<...>`) - rust-lang#117957 (if available use a Child's pidfd for kill/wait) - rust-lang#117988 (Handle attempts to have multiple `cfg`d tail expressions) - rust-lang#117994 (Ignore but do not assume region obligations from unifying headers in negative coherence) - rust-lang#118000 (Make regionck care about placeholders in outlives components) - rust-lang#118068 (subtree update cg_gcc 2023/11/17) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#117994 - compiler-errors:throw-away-regions-in-coherence, r=lcnr Ignore but do not assume region obligations from unifying headers in negative coherence Partly addresses a FIXME that was added in rust-lang#112875. Just as we can throw away the nested trait/projection obligations from unifying two impl headers, we can also just throw away the region obligations too. I removed part of the FIXME that was incorrect, namely: > Given that the only region constraints we get are involving inference regions in the root, it shouldn't matter, but still sus. This is not true when unifying `fn(A)` and `for<'b> fn(&'b B)` which ends up with placeholder region outlives from non-root universes. I'm pretty sure this is okay, though it would be nice if we were to use them as assumptions. See the `explicit` revision of the test I committed, which still fails. Fixes rust-lang#117986 r? lcnr, feel free to reassign tho.

rustbot assigned lcnr Nov 16, 2023

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 Nov 16, 2023

compiler-errors mentioned this pull request Nov 17, 2023

Make regionck care about placeholders in outlives components #118000

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bors 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 Nov 17, 2023

matthiaskrgr mentioned this pull request Nov 17, 2023

Rollup of 7 pull requests #118019

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TaKO8Ki mentioned this pull request Nov 18, 2023

Rollup of 8 pull requests #118041

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compiler-errors mentioned this pull request Nov 18, 2023

Rollup of 9 pull requests #118049

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bors 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-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Nov 18, 2023

aliemjay reviewed Nov 19, 2023

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Ignore but do not assume region obligations from unifying headers in …

488dcb7

…negative coherence

rust-cloud-vms bot force-pushed the throw-away-regions-in-coherence branch from d688b86 to 488dcb7 Compare November 19, 2023 19:23

bors 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Nov 19, 2023

compiler-errors mentioned this pull request Nov 20, 2023

Rollup of 8 pull requests #118078

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compiler-errors mentioned this pull request Nov 20, 2023

Don't require intercrate mode for negative coherence #117992

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compiler-errors mentioned this pull request Nov 20, 2023

Rollup of 8 pull requests #118082

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bors merged commit 40a781b into rust-lang:master Nov 20, 2023

rustbot added this to the 1.76.0 milestone Nov 20, 2023

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Ignore but do not assume region obligations from unifying headers in negative coherence#117994

Ignore but do not assume region obligations from unifying headers in negative coherence#117994
bors merged 1 commit intorust-lang:masterfrom
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		let _ = infcx.take_registered_region_obligations();
		let _ = infcx.take_and_reset_region_constraints();

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