add missing import of Id(..).
import DsUtils
import CoreUtils ( coreExprType )
import DsUtils
import CoreUtils ( coreExprType )
-import Id ( dataConArgTys, dataConTyCon, idType )
+import Id ( Id(..), dataConArgTys, dataConTyCon, idType )
import Maybes ( maybeToBool )
import Outputable ( PprStyle(..), Outputable(..) )
import PprType ( GenType{-instances-} )
import Maybes ( maybeToBool )
import Outputable ( PprStyle(..), Outputable(..) )
import PprType ( GenType{-instances-} )