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//@ known-bug: rust-lang/rust#126944
// Step 1: Create two names for a single type: `Thing` and `AlsoThing`
struct Thing;
struct Dummy;
pub trait DummyTrait {
type DummyType;
}
impl DummyTrait for Dummy {
type DummyType = Thing;
}
type AlsoThing = <Dummy as DummyTrait>::DummyType;
// Step 2: Create names for a single trait object type: `TraitObject` and `AlsoTraitObject`
pub trait SomeTrait {
type Item;
}
type TraitObject = dyn SomeTrait<Item = AlsoThing>;
type AlsoTraitObject = dyn SomeTrait<Item = Thing>;
// Step 3: Force the compiler to check whether the two names are the same type
pub trait Supertrait {
type Foo;
}
pub trait Subtrait: Supertrait<Foo = TraitObject> {}
pub trait HasOutput<A: ?Sized> {
type Output;
}
fn foo<F>() -> F::Output
where
F: HasOutput<dyn Subtrait<Foo = AlsoTraitObject>>,
{
todo!()
}
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