Don't ICE when deducing future output if other errors already occurred #120057

oli-obk · 2024-01-17T14:53:49Z

The situation can't really happen outside of erroneous code. What was interesting is that it ICEd before emitting any other diagnostics. This was because the other errors were silenced due to cycle_delay_bug cycle errors.

r? @compiler-errors

fixes #119890

compiler-errors · 2024-01-17T14:56:11Z

compiler/rustc_hir_typeck/src/closure.rs

-                .find_map(|(p, s)| get_future_output(p.as_predicate(), s))?,
+            ty::Alias(kind, ty::AliasTy { def_id, args, .. }) => {
+                match kind {
+                    ty::Projection => assert!(self.tcx.is_impl_trait_in_trait(def_id)),


This projection should have been normalized to its corresponding opaque at this point. Why isn't that happening here?

I'm assuming it's one of the other errors. I'll see if I can find something out

I haven't figured out yet how we get here, but the root issue seems to be that we have a query cycle at

#0 [object_safety_violations] determining object safety of trait `Foo` #1 [check_is_object_safe] checking if trait `Foo` is object safe #2 [fn_sig] computing function signature of `Foo::foo`

The fn_sig query tries to emit an error. But to get the information to emit a good diagnostic, it ends up triggering a cycle error, thus hiding the as-of-yet unreported diagnostic and instead cycle_delay_bugging out with an error fn signature.

ok thats fine i guess

could you delay this as a bug saying something like "this projection should have been projected to an opaque type"?

r=me after

I have found an entirely different solution. How do you like this one?

rustbot · 2024-01-17T16:08:13Z

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compiler/rustc_middle/src/traits/mod.rs

rustbot · 2024-01-17T16:27:08Z

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oli-obk · 2024-01-17T16:28:45Z

@bors r=compiler-errors

bors · 2024-01-17T16:28:48Z

📌 Commit f1ef930 has been approved by compiler-errors

It is now in the queue for this repository.

…r=compiler-errors Don't ICE when deducing future output if other errors already occurred The situation can't really happen outside of erroneous code. What was interesting is that it ICEd before emitting any other diagnostics. This was because the other errors were silenced due to cycle_delay_bug cycle errors. r? `@compiler-errors` fixes rust-lang#119890

…r=compiler-errors Don't ICE when deducing future output if other errors already occurred The situation can't really happen outside of erroneous code. What was interesting is that it ICEd before emitting any other diagnostics. This was because the other errors were silenced due to cycle_delay_bug cycle errors. r? ``@compiler-errors`` fixes rust-lang#119890

…iaskrgr Rollup of 7 pull requests Successful merges: - rust-lang#119172 (Detect `NulInCStr` error earlier.) - rust-lang#119833 (Make tcx optional from StableMIR run macro and extend it to accept closures) - rust-lang#119955 (Modify GenericArg and Term structs to use strict provenance rules) - rust-lang#120021 (don't store const var origins for known vars) - rust-lang#120038 (Don't create a separate "basename" when naming and opening a MIR dump file) - rust-lang#120057 (Don't ICE when deducing future output if other errors already occurred) - rust-lang#120073 (Remove spastorino from users_on_vacation) r? `@ghost` `@rustbot` modify labels: rollup

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#119172 (Detect `NulInCStr` error earlier.) - rust-lang#119833 (Make tcx optional from StableMIR run macro and extend it to accept closures) - rust-lang#119967 (Add `PatKind::Err` to AST/HIR) - rust-lang#119978 (Move async closure parameters into the resultant closure's future eagerly) - rust-lang#120021 (don't store const var origins for known vars) - rust-lang#120038 (Don't create a separate "basename" when naming and opening a MIR dump file) - rust-lang#120057 (Don't ICE when deducing future output if other errors already occurred) - rust-lang#120073 (Remove spastorino from users_on_vacation) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#120057 - oli-obk:not_sure_wtf_is_going_on, r=compiler-errors Don't ICE when deducing future output if other errors already occurred The situation can't really happen outside of erroneous code. What was interesting is that it ICEd before emitting any other diagnostics. This was because the other errors were silenced due to cycle_delay_bug cycle errors. r? ```@compiler-errors``` fixes rust-lang#119890

rustbot assigned compiler-errors Jan 17, 2024

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 Jan 17, 2024

compiler-errors reviewed Jan 17, 2024

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oli-obk force-pushed the not_sure_wtf_is_going_on branch from f6a8294 to f75bcf3 Compare January 17, 2024 16:07

oli-obk changed the title ~~Enable deducing future output for impl trait in trait~~ Treat errors in signatures as an object safety violation Jan 17, 2024

compiler-errors reviewed Jan 17, 2024

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compiler/rustc_middle/src/traits/mod.rs Outdated Show resolved Hide resolved

oli-obk changed the title ~~Treat errors in signatures as an object safety violation~~ Don't ICE when deducing future output if other errors already occurred Jan 17, 2024

Don't ICE when deducing future output if other errors already occurred

f1ef930

oli-obk force-pushed the not_sure_wtf_is_going_on branch from bf2a126 to f1ef930 Compare January 17, 2024 16:28

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 Jan 17, 2024

matthiaskrgr mentioned this pull request Jan 18, 2024

Rollup of 8 pull requests #120087

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matthiaskrgr mentioned this pull request Jan 18, 2024

Rollup of 7 pull requests #120088

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matthiaskrgr mentioned this pull request Jan 18, 2024

Rollup of 8 pull requests #120089

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bors merged commit 34362b8 into rust-lang:master Jan 18, 2024
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rustbot added this to the 1.77.0 milestone Jan 18, 2024

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Don't ICE when deducing future output if other errors already occurred #120057

Don't ICE when deducing future output if other errors already occurred #120057

oli-obk commented Jan 17, 2024 •

edited

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Don't ICE when deducing future output if other errors already occurred #120057

Don't ICE when deducing future output if other errors already occurred #120057

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edited