0d56699d41
`Trait`, prefer the object. Also give a nice error for attempts to manually `impl Trait for Trait`, since they will be ineffectual. Fixes #24015. Fixes #24051. Fixes #24037. Fixes #23853. Fixes #21942. cc #21756.
28 lines
915 B
Rust
28 lines
915 B
Rust
// 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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// Test that we are able to compile the case where both a blanket impl
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// and the object type itself supply the required trait obligation.
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// In this case, the blanket impl for `Foo` applies to any type,
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// including `Bar`, but the object type `Bar` also implicitly supplies
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// this context.
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trait Foo { fn dummy(&self) { } }
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trait Bar: Foo { }
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impl<T:?Sized> Foo for T { }
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fn want_foo<B:?Sized+Foo>() { }
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fn main() {
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want_foo::<Bar>();
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}
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