extractHsTyNames_s :: [LHsType Name] -> NameSet
extractHsTyNames_s tys = foldr (unionNameSets . extractHsTyNames) emptyNameSet tys
extractHsTyNames_s :: [LHsType Name] -> NameSet
extractHsTyNames_s tys = foldr (unionNameSets . extractHsTyNames) emptyNameSet tys