32 lines
1.0 KiB
Rust
32 lines
1.0 KiB
Rust
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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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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