mirror of https://github.com/rust-lang/rust
34 lines
933 B
Rust
34 lines
933 B
Rust
//@ check-pass
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#![feature(type_alias_impl_trait)]
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trait Duh {}
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impl Duh for i32 {}
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trait Trait {
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type Assoc: Duh;
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}
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// the fact that `R` is the `::Output` projection on `F` causes
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// an intermediate inference var to be generated which is then later
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// compared against the actually found `Assoc` type.
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impl<R: Duh, F: FnMut() -> R> Trait for F {
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type Assoc = R;
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}
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type Traitable = impl Trait<Assoc = impl Send>;
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//~^ WARN opaque type `Traitable` does not satisfy its associated type bounds
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// The `impl Send` here is then later compared against the inference var
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// created, causing the inference var to be set to `impl Send` instead of
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// the hidden type. We already have obligations registered on the inference
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// var to make it uphold the `: Duh` bound on `Trait::Assoc`. The opaque
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// type does not implement `Duh`, even if its hidden type does. So we error out.
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fn foo() -> Traitable {
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|| 42
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}
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fn main() {
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}
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