cmpTypeX :: RnEnv2 -> Type -> Type -> Ordering  -- Main workhorse
cmpTypeX env t1 t2 | Just t1' <- coreView t1 = cmpTypeX env t1' t2
                   | Just t2' <- coreView t2 = cmpTypeX env t1 t2'
cmpTypeX :: RnEnv2 -> Type -> Type -> Ordering
cmpTypeX env t1 t2 | Just t1' <- coreView t1 = cmpTypeX env t1' t2
                   | Just t2' <- coreView t2 = cmpTypeX env t1 t2'
cmpTypeX env t1 t2 | Just t1' <- coreView t1 = cmpTypeX env t1' t2
                   | Just t2' <- coreView t2 = cmpTypeX env t1 t2'