src/test/ui/specialization/deafult-generic-associated-type-bound.rs

// Check that default generics associated types are validated.

#![feature(specialization)]
#![feature(generic_associated_types)]
//~^^ WARNING `specialization` is incomplete
//~^^ WARNING the feature `generic_associated_types` is incomplete

trait X {
    type U<'a>: PartialEq<&'a Self>;
    fn unsafe_compare<'b>(x: Option<Self::U<'b>>, y: Option<&'b Self>) {
        match (x, y) {
            (Some(a), Some(b)) => a == b,
            _ => false,
        };
    }
}

impl<T: 'static> X for T {
    default type U<'a> = &'a T;
    //~^ ERROR can't compare `T` with `T`
}

struct NotComparable;

pub fn main() {
    <NotComparable as X>::unsafe_compare(None, None);
}