Allow opaque types in trait impl headers and rely on coherence to reject unsound cases#103488

oli-obk · 2022-10-24T15:48:41Z

lcnr

this is still unsound when equating two opaque types with the same DefId during coherence, similar to #102048. With the current setup that might be difficult to fix, though I might be wrong.

We can land this PR and then I can try to write an example and open an issue.

compiler/rustc_middle/src/ty/fast_reject.rs

lcnr · 2022-10-24T16:47:37Z

src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs

expected, still weird 😁

oli-obk · 2022-10-27T12:02:34Z

src/test/ui/type-alias-impl-trait/impl_trait_for_same_tait.stderr

I'm not sure yet how to improve this diagnostic beyond looking at the entries in take_opaque_types() and doing some guessing for common cases.

bors · 2022-10-29T17:48:07Z

☔ The latest upstream changes (presumably #103727) made this pull request unmergeable. Please resolve the merge conflicts.

compiler/rustc_middle/src/ty/relate.rs

src/test/ui/type-alias-impl-trait/impl_trait_for_same_tait.rs

rustbot · 2022-11-03T07:55:15Z

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

bors · 2022-11-04T04:21:29Z

☔ The latest upstream changes (presumably #101834) made this pull request unmergeable. Please resolve the merge conflicts.

compiler/rustc_infer/src/infer/mod.rs

src/test/ui/type-alias-impl-trait/impl_trait_for_same_tait.rs

compiler/rustc_infer/src/infer/combine.rs

lcnr · 2022-11-14T12:54:39Z

compiler/rustc_infer/src/infer/combine.rs

that should be reachable when using generic const exprs when relating a const inference var (from a const param) with an unevaluated constant during coherence

compiler/rustc_infer/src/infer/nll_relate/mod.rs

compiler/rustc_infer/src/infer/error_reporting/mod.rs

compiler/rustc_infer/src/infer/glb.rs

compiler/rustc_infer/src/infer/lub.rs

compiler/rustc_infer/src/infer/combine.rs

…ect unsound cases

bors · 2022-11-21T16:05:08Z

☔ The latest upstream changes (presumably #103491) made this pull request unmergeable. Please resolve the merge conflicts.

…ence

…lally allow trait resolution to prove false things during coherence

lcnr

r=me

lcnr · 2022-11-22T13:45:00Z

src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.rs

+
+// Ok because `i32` does not implement `Dummy`,
+// so it can't possibly be the hidden type of `F`.
+impl Test for i32 {


how does that work? 🤔

when coherence is checking whether F conflicts with i32 we register i32 as the hidden type of F and that fails because i32: !Dummy but F = impl Dummy.

oli-obk · 2022-11-22T13:54:32Z

@bors r=lcnr

bors · 2022-11-22T13:54:34Z

📌 Commit c16a90f has been approved by lcnr

It is now in the queue for this repository.

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? `@lcnr` fixes rust-lang#99840

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? ``@lcnr`` fixes rust-lang#99840

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? ```@lcnr``` fixes rust-lang#99840

…earth Rollup of 6 pull requests Successful merges: - rust-lang#103488 (Allow opaque types in trait impl headers and rely on coherence to reject unsound cases) - rust-lang#104359 (Refactor must_use lint into two parts) - rust-lang#104612 (Lower return type outside async block creation) - rust-lang#104621 (Fix --extern library finding errors) - rust-lang#104647 (enable fuzzy_provenance_casts lint in liballoc and libstd) - rust-lang#104750 (Bump `fd-lock` in `bootstrap` again) Failed merges: - rust-lang#104732 (Refactor `ty::ClosureKind` related stuff) r? `@ghost` `@rustbot` modify labels: rollup

Mark-Simulacrum · 2022-11-29T13:16:55Z

This PR was a perf regression (see the report here #104758 (comment)). It's relatively small and mostly limited to secondary workloads so I'm marking as triaged.

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? ````@lcnr```` fixes rust-lang#99840

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Oct 24, 2022

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Allow opaque types in trait impl headers and rely on coherence to rej…

2752e32

…ect unsound cases

oli-obk added 6 commits November 21, 2022 16:06

Treat different opaque types of the same def id as equal during coher…

94fe30f

…ence

Add an always-ambiguous predicate to make sure that we don't accident…

ae80c76

…lally allow trait resolution to prove false things during coherence

nit treat different opaque types

9cd44f8

Move a field around

9a8e1ee

Register obligations from type relation

f42e490

Remove a function that doesn't actually do anything

11ae334

oli-obk added 2 commits November 21, 2022 16:38

Type generalization should not look at opaque type in coherence

7301cd7

Add some more assertions for type relations not used during coherence

11adf03

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Test generalization during coherence

c16a90f

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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 22, 2022

Manishearth added a commit to Manishearth/rust that referenced this pull request Nov 22, 2022

Rollup merge of rust-lang#103488 - oli-obk:impl_trait_for_tait, r=lcnr

43eb708

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? `@lcnr` fixes rust-lang#99840

Manishearth mentioned this pull request Nov 22, 2022

Rollup of 11 pull requests #104738

Closed

Manishearth mentioned this pull request Nov 22, 2022

Rollup of 10 pull requests #104749

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This was referenced Nov 23, 2022

Rollup of 7 pull requests #104756

Closed

Rollup of 6 pull requests #104758

Merged

bors merged commit 53eab24 into rust-lang:master Nov 23, 2022

rustbot added this to the 1.67.0 milestone Nov 23, 2022

oli-obk deleted the impl_trait_for_tait branch November 23, 2022 10:25

compiler-errors mentioned this pull request Nov 24, 2022

ICE: ty_is_local invoked on closure or generator #104817

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Mark-Simulacrum added the perf-regression Performance regression. label Nov 29, 2022

Mark-Simulacrum added the perf-regression-triaged The performance regression has been triaged. label Nov 29, 2022

flip1995 pushed a commit to flip1995/rust that referenced this pull request Dec 1, 2022

Rollup merge of rust-lang#103488 - oli-obk:impl_trait_for_tait, r=lcnr

91d2ce3

Allow opaque types in trait impl headers and rely on coherence to reject unsound cases r? ````@lcnr```` fixes rust-lang#99840

aliemjay mentioned this pull request Apr 2, 2023

remove TypeRelation::{intercrate,mark_ambiguous} #109863

Closed

matthiaskrgr mentioned this pull request Apr 22, 2023

ICE failed to resolve instance for #110696

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