#![feature(type_alias_impl_trait)] //@ check-pass pub type Foo = impl PartialEq<(Foo, i32)>; #[define_opaque(Foo)] fn foo() -> Foo { Bar } struct Bar; impl PartialEq<(Foo, i32)> for Bar { fn eq(&self, _other: &(Foo, i32)) -> bool { true } } fn main() {}