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// check-pass
// edition:2018
#![feature(type_alias_impl_trait)]
#![feature(impl_trait_in_bindings)]
//~^ WARNING the feature `impl_trait_in_bindings` is incomplete
// See issue 60414
// Reduction to `impl Trait`
struct Foo<T>(T);
trait FooLike { type Output; }
impl<T> FooLike for Foo<T> {
type Output = T;
}
mod impl_trait {
use super::*;
trait Trait {
type Assoc;
}
/// `T::Assoc` should be normalized to `()` here.
fn foo_pass<T: Trait<Assoc=()>>() -> impl FooLike<Output=T::Assoc> {
Foo(())
}
}
// Same with lifetimes in the trait
mod lifetimes {
use super::*;
trait Trait<'a> {
type Assoc;
}
/// Like above.
///
/// FIXME(#51525) -- the shorter notation `T::Assoc` winds up referencing `'static` here
fn foo2_pass<'a, T: Trait<'a, Assoc=()> + 'a>(
) -> impl FooLike<Output=<T as Trait<'a>>::Assoc> + 'a {
Foo(())
}
/// Normalization to type containing bound region.
///
/// FIXME(#51525) -- the shorter notation `T::Assoc` winds up referencing `'static` here
fn foo2_pass2<'a, T: Trait<'a, Assoc=&'a ()> + 'a>(
) -> impl FooLike<Output=<T as Trait<'a>>::Assoc> + 'a {
Foo(&())
}
}
// Reduction using `impl Trait` in bindings
mod impl_trait_in_bindings {
struct Foo;
trait FooLike { type Output; }
impl FooLike for Foo {
type Output = u32;
}
trait Trait {
type Assoc;
}
fn foo<T: Trait<Assoc=u32>>() {
let _: impl FooLike<Output=T::Assoc> = Foo;
}
}
// The same applied to `type Foo = impl Bar`s
mod opaque_types {
trait Implemented {
type Assoc;
}
impl<T> Implemented for T {
type Assoc = u8;
}
trait Trait {
type Out;
}
impl Trait for () {
type Out = u8;
}
type Ex = impl Trait<Out = <() as Implemented>::Assoc>;
fn define() -> Ex {
()
}
}
fn main() {}
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