{-# LANGUAGE DataKinds #-} {-# LANGUAGE DerivingStrategies #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE PolyKinds #-} {-# LANGUAGE StandaloneDeriving #-} {-# LANGUAGE UnliftedNewtypes #-} module T15883c where import GHC.Exts newtype Foo rep = MkFoo (forall (a :: TYPE rep). a) deriving stock instance Ord (Foo (BoxedRep Lifted))