60 lines
1.5 KiB
Rust
60 lines
1.5 KiB
Rust
// Copyright 2014 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 coherence detects overlap when some of the types in the
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// impls are projections of associated type. Issue #20624.
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use std::marker::PhantomData;
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use std::ops::Deref;
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pub struct Cow<'a, B: ?Sized>(PhantomData<(&'a (),B)>);
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/// Trait for moving into a `Cow`
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pub trait IntoCow<'a, B: ?Sized> {
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/// Moves `self` into `Cow`
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fn into_cow(self) -> Cow<'a, B>;
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}
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impl<'a, B: ?Sized> IntoCow<'a, B> for Cow<'a, B> where B: ToOwned {
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//~^ ERROR E0119
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fn into_cow(self) -> Cow<'a, B> {
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self
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}
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}
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impl<'a, B: ?Sized> IntoCow<'a, B> for <B as ToOwned>::Owned where B: ToOwned {
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//~^ ERROR E0119
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fn into_cow(self) -> Cow<'a, B> {
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Cow
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}
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}
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impl<'a, B: ?Sized> IntoCow<'a, B> for &'a B where B: ToOwned {
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fn into_cow(self) -> Cow<'a, B> {
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Cow
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}
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}
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impl ToOwned for u8 {
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type Owned = &'static u8;
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fn to_owned(&self) -> &'static u8 { panic!() }
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}
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/// A generalization of Clone to borrowed data.
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pub trait ToOwned {
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type Owned;
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/// Create owned data from borrowed data, usually by copying.
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fn to_owned(&self) -> Self::Owned;
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}
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fn main() {}
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