tyConTheta, maybeTyConSingleCon, isDataTyCon,
isEnumerationTyCon, TyCon
)
-import Type ( TauType, ThetaType, PredType, mkTyVarTys, mkTyConApp,
+import Type ( ThetaType, mkTyVarTys, mkTyConApp,
isUnLiftedType, mkClassPred )
import Var ( TyVar )
import PrelNames