TAIT: type parameter `impl FnOnce()` is part of concrete type but not used in parameter list for the `impl Trait` type alias about rust HOT 4 CLOSED

#![feature(type_alias_impl_trait)]

fn foo<T2>(bar: T2) {
    type T = impl Sized;
    let x: T = || {};
}

fn main() {}

#![feature(type_alias_impl_trait)]

fn foo<U>() {
    type T<V> = impl Sized;
    let x: T<U> = || (); //~ OK
}

fn main() {}

#![feature(type_alias_impl_trait)]

type Ty = impl Sized;

fn test<'v, T, const U: usize>() -> Ty {
    || ()
    //~^ ERROR type parameter `T` is part of concrete type but not
    //~|       used in parameter list for the `impl Trait` type alias
    //~^ ERROR const parameter `U` is part of concrete type but not
    //~|       used in parameter list for the `impl Trait` type alias
}

fn main() {}