rustc/tests/ui/const-generics/generic_const_exprs/mismatched-gat-subst-kind.rs

#![feature(generic_const_exprs)]
//~^ WARN the feature `generic_const_exprs` is incomplete

trait B {
    type U<T>;
}

fn f<T: B<U<1i32> = ()>>() {}
//~^ ERROR constant provided when a type was expected

fn main() {}