Definition expr_closed_wrt_lvars (S: ident -> Prop) (e: expr) : Prop :=
  forall (cs: compspecs) rho ve',
     (forall i, S i \/ Map.get (ve_of rho) i = Map.get ve' i) ->
     eval_expr e rho = eval_expr e (mkEnviron (ge_of rho) ve' (te_of rho)).Definition lvalue_closed_wrt_lvars (S: ident -> Prop) (e: expr) : Prop :=
  forall (cs: compspecs) rho ve',
     (forall i, S i \/ Map.get (ve_of rho) i = Map.get ve' i) ->
     eval_lvalue e rho = eval_lvalue e (mkEnviron (ge_of rho) ve'  (te_of rho)).

Lemma closed_wrt_exp: forall {A} S (P: A -> environ->mpred), (forall a, closed_wrt_vars S (P a)) -> closed_wrt_vars S (exp P).