Hint Extern 2 (closed_wrt_vars (eq _) _) =>
(apply closed_wrt_ideq; [solve [let Hx := fresh in (intro Hx; inv Hx)] | reflexivity]) : closed.

Lemma closed_wrt_tc_nonzero:
forall {cs: compspecs} S e,
closed_wrt_vars S (eval_expr e) ->
closed_wrt_vars S (denote_tc_assert (tc_nonzero e)).