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Rollup merge of #99356 - compiler-errors:tait-in-assoc-ty-supertraits…
…, r=oli-obk Do not constraint TAITs when checking impl/trait item compatibility Check out the UI test for the example. Open to other approaches to fix this issue -- ideally we _would_ be able to collect this opaque type constraint in a way to use it in `find_opaque_ty_constraints`, so we can report a better mismatch error in the incompatible case, and just allow it in the compatible case. But that seems like a bigger refactor, so I wouldn't want to start it unless someone else thought it was a good idea. cc #99348 r? ``@oli-obk``
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src/test/ui/impl-trait/issues/issue-99348-impl-compatibility.rs
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#![feature(type_alias_impl_trait)] | ||
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struct Concrete; | ||
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type Tait = impl Sized; | ||
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impl Foo for Concrete { | ||
type Item = Concrete; | ||
//~^ mismatched types | ||
} | ||
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impl Bar for Concrete { | ||
type Other = Tait; | ||
} | ||
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trait Foo { | ||
type Item: Bar<Other = Self>; | ||
} | ||
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trait Bar { | ||
type Other; | ||
} | ||
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fn tait() -> Tait {} | ||
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fn main() {} |
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src/test/ui/impl-trait/issues/issue-99348-impl-compatibility.stderr
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error[E0308]: mismatched types | ||
--> $DIR/issue-99348-impl-compatibility.rs:8:17 | ||
| | ||
LL | type Tait = impl Sized; | ||
| ---------- the expected opaque type | ||
... | ||
LL | type Item = Concrete; | ||
| ^^^^^^^^ types differ | ||
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= note: expected opaque type `Tait` | ||
found struct `Concrete` | ||
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error: aborting due to previous error | ||
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For more information about this error, try `rustc --explain E0308`. |