{-# LANGUAGE GADTs #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE PolyKinds, DataKinds #-} module T5716 where import Data.Kind (Type) data family DF a data instance DF Int = DFInt data U = U1 (DF Int) data I :: U -> Type where I1 :: I (U1 DFInt)