23 lines
612 B
Rust
23 lines
612 B
Rust
//@ run-pass
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// check that trait matching can handle impls whose types are only
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// constrained by a projection.
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trait IsU32 {}
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impl IsU32 for u32 {}
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trait Mirror { type Image: ?Sized; }
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impl<T: ?Sized> Mirror for T { type Image = T; }
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trait Bar {}
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impl<U: Mirror, V: Mirror<Image=L>, L: Mirror<Image=U>> Bar for V
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where U::Image: IsU32 {}
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trait Foo { fn name() -> &'static str; }
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impl Foo for u64 { fn name() -> &'static str { "u64" } }
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impl<T: Bar> Foo for T { fn name() -> &'static str { "Bar" }}
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fn main() {
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assert_eq!(<u64 as Foo>::name(), "u64");
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assert_eq!(<u32 as Foo>::name(), "Bar");
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}
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