} else if cat_a == cat_b {
match (a.kind(), b.kind()) {
(ty::Adt(def_a, _), ty::Adt(def_b, _)) => def_a == def_b,
+ (ty::Foreign(def_a), ty::Foreign(def_b)) => def_a == def_b,
// Matching on references results in a lot of unhelpful
// suggestions, so let's just not do that for now.
//