get (HsOpTy ty1 tycon ty2) = get ty1 `unionNameSets` get ty2 `unionNameSets`
case tycon of { HsTyOp n -> unitNameSet n ;
HsArrow -> emptyNameSet }
+ get (HsParTy ty) = get ty
get (HsNumTy n) = emptyNameSet
get (HsTyVar tv) = unitNameSet tv
get (HsKindSig ty k) = get ty