intros.
destruct e; auto. simpl.
repeat
match goal with
| [ |- context [match ?e with _ => _ end] ] => destruct e; auto
end.
admit.
Admitted.
(* Qed. (* :( *) *)

Lemma SYMEXE_STEP_sound: forall Struct_env, rtac_sound (SYMEXE_STEP tbl Struct_env).