- tau_tvs = foldr (unionVarSet . exactTyVarsOfType . getMonoType) emptyVarSet mono_infos
- -- NB: exactTyVarsOfType; see Note [Silly type synonym]
- -- near defn of TcType.exactTyVarsOfType
+ get_tvs | isTopLevel top_lvl = tyVarsOfType -- See Note [Silly type synonym] in TcType
+ | otherwise = exactTyVarsOfType
+ tau_tvs = foldr (unionVarSet . get_tvs . getMonoType) emptyVarSet mono_infos