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_wrtl_tc_isptr: forall {cs: compspecs} S e, expr_closed_wrt_lvars S e -> closed_wrt_lvars S (denote_tc_assert (tc_isptr e)).