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

// ignore-compare-mode-chalk
// revisions: min_tait full_tait
#![feature(min_type_alias_impl_trait)]
#![cfg_attr(full_tait, feature(type_alias_impl_trait))]

pub trait Bar {
    type E: Copy;

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

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

    fn foo<T>() -> Self::E {
        //~^ ERROR type parameter `T` is part of concrete type but not used in parameter list for the `impl Trait` type alias
        || ()
    }
}

fn main() {}