= (noLoc (vName i), noLoc $ BangType HsNoBang (cvtType ty))
mk_derivs [] = Nothing
-mk_derivs cs = Just (noLoc [noLoc $ HsClassP (tconName c) [] | c <- cs])
+mk_derivs cs = Just [noLoc $ HsPredTy $ noLoc $ HsClassP (tconName c) [] | c <- cs]
cvt_ltop :: TH.Dec -> Either (LHsDecl RdrName) Message
cvt_ltop d = case cvt_top d of