(* Lemma typecheck_environ_join_switch2: forall sl Delta rho, typecheck_environ Delta rho -> typecheck_environ (join_tycon_labeled sl Delta) rho.  Lemma typecheck_environ_join_switch1: forall n sl rho Delta, typecheck_environ (update_tycon Delta (seq_of_labeled_statement (select_switch n sl))) rho -> typecheck_environ (join_tycon_labeled sl Delta) rho. *)

Lemma prop_true_imp:
forall {A} {agA: ageable A} (P: Prop) (Q: pred A),
P ->   (!! P --> Q)%pred = Q.