mirror of https://github.com/rust-lang/rust
28 lines
780 B
Rust
28 lines
780 B
Rust
// We try to prove `for<'b> T::Rigid: Bound<'b, ?0>` and have 2 candidates from where-clauses:
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//
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// - `for<'a> Bound<'a, String>`
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// - `for<'a> Bound<'a, <T::Rigid as Elaborate>::Assoc>`
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//
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// This causes ambiguity unless we normalize the alias in the second candidate
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// to detect that they actually result in the same constraints. We currently
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// fail to detect that the constraints from these bounds are equal and error
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// with ambiguity.
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trait Bound<'a, U> {}
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trait Trait {
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type Rigid: Elaborate<Assoc = String> + for<'a> Bound<'a, String>;
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}
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trait Elaborate: for<'a> Bound<'a, Self::Assoc> {
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type Assoc;
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}
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fn impls<T: for<'b> Bound<'b, U>, U>(_: T) {}
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fn test<P: Trait>(rigid: P::Rigid) {
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impls(rigid);
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//~^ ERROR type annotations needed
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}
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fn main() {}
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