Hint Resolve expr_closed_binop expr_closedl_binop : closed.

(* Specifications: *)
Lemma expr_closed_unop: forall {cs: compspecs} S op e t,
expr_closed_wrt_vars S e ->
expr_closed_wrt_vars S (Eunop op e t).
Lemma expr_closedl_unop: forall S op e t,
expr_closed_wrt_lvars S e ->
expr_closed_wrt_lvars S (Eunop op e t).