+ | (i,t) <- drop extra_args $
+ zip [0..] (filter isPointed subTtypes)]
+ _ -> return []
+
+ -- This helper computes the difference between a base type t and the
+ -- improved rtti_t computed by RTTI
+ -- The main difference between RTTI types and their normal counterparts
+ -- is that the former are _not_ polymorphic, thus polymorphism must
+ -- be stripped. Syntactically, forall's must be stripped
+computeRTTIsubst :: Type -> Type -> Maybe TvSubst
+computeRTTIsubst ty rtti_ty =
+ -- In addition, we strip newtypes too, since the reconstructed type might
+ -- not have recovered them all
+ tcUnifyTys (const BindMe)
+ [repType' $ dropForAlls$ ty]
+ [repType' $ rtti_ty]
+-- TODO stripping newtypes shouldn't be necessary, test