rust/tests/ui/specialization/defaultimpl/projection.rs

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// run-pass
#![allow(dead_code)]
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#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
// Make sure we *can* project non-defaulted associated types
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// cf ui/specialization/specialization-default-projection.rs
// First, do so without any use of specialization
trait Foo {
type Assoc;
}
impl<T> Foo for T {
type Assoc = ();
}
fn generic_foo<T>() -> <T as Foo>::Assoc {
()
}
// Next, allow for one layer of specialization
trait Bar {
type Assoc;
}
default impl<T> Bar for T {
type Assoc = ();
}
impl<T: Clone> Bar for T {
type Assoc = u8;
}
fn generic_bar_clone<T: Clone>() -> <T as Bar>::Assoc {
0u8
}
fn main() {
}