data B1 a = B1 a
data instance C.F (B1 a) = B2 a
type role D nominal
data family D a
class C.C1 a where
  type role C.F nominal
  data family C.F a
  	-- Defined at T5417a.hs:5:5
data instance C.F (B1 a) = B2 a 	-- Defined at T5417.hs:8:10