isInScope :: Var -> TvSubst -> Bool
isInScope v (TvSubst in_scope _) = v `elemInScopeSet` in_scope
isInScope :: Var -> TvSubst -> Bool
isInScope v (TvSubst in_scope _) = v `elemInScopeSet` in_scope
isInScope v (TvSubst in_scope _) = v `elemInScopeSet` in_scope