cvt_top d@(Val _ _ _) = ValD (cvtd d)
cvt_top d@(Fun _ _) = ValD (cvtd d)
+cvt_top (TySyn tc tvs rhs)
+ = TyClD (TySynonym (tconName tc) (cvt_tvs tvs) (cvtType rhs) loc0)
+
cvt_top (Data tc tvs constrs derivs)
= TyClD (mkTyData DataType
(noContext, tconName tc, cvt_tvs tvs)