mirror of https://github.com/rust-lang/rust
50 lines
1.1 KiB
Rust
50 lines
1.1 KiB
Rust
// 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 <B as ToOwned>::Owned where B: ToOwned {
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fn into_cow(self) -> Cow<'a, B> {
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Cow(PhantomData)
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}
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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 &'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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Cow(PhantomData)
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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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/// Creates 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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