//@ revisions: current next //@ ignore-compare-mode-next-solver (explicit revisions) //@[next] compile-flags: -Znext-solver #![feature(type_alias_impl_trait)] type A = impl Foo; type B = impl Foo; trait Foo {} #[define_opaque(A, B)] fn muh(x: A) -> B { //[next]~^ ERROR: cannot satisfy `_ == A` x // B's hidden type is A (opaquely) //[current]~^ ERROR opaque type's hidden type cannot be another opaque type } struct Bar; impl Foo for Bar {} fn main() {}