rust/src/test/ui/impl-trait/issue-55872-1.rs

#![feature(type_alias_impl_trait)]

pub trait Bar {
    type E: Copy;

    fn foo<T>() -> Self::E;
}

impl<S: Default> Bar for S {
    type E = impl Copy;

    fn foo<T: Default>() -> Self::E {
        //~^ ERROR type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
        //~| ERROR impl has stricter requirements than trait
        //~| ERROR the trait bound `S: Copy` is not satisfied in `(S, T)` [E0277]
        //~| ERROR the trait bound `T: Copy` is not satisfied in `(S, T)` [E0277]
        (S::default(), T::default())
    }
}

fn main() {}