getGates source_fvs (SigD (IfaceSig _ ty _ _))
= extractHsTyNames ty
-getGates source_fvs (TyClD (ClassDecl ctxt cls tvs sigs _ _ _ _ _ _))
+getGates source_fvs (TyClD (ClassDecl ctxt cls tvs _ sigs _ _ _ _ _ _))
= delListFromNameSet (foldr (plusFV . get) (extractHsCtxtTyNames ctxt) sigs)
(map getTyVarName tvs)
`addOneToNameSet` cls