Proof using.
intros.
eapply message_labels_eventually_occur;
eauto using Lock_enables_MsgLock, Lock_delivered_MsgLock.
unfold label_silent. simpl. congruence.
Qed.

(* Specifications: *)
Lemma InputLock_eventually_MsgLock :
forall c s,
lb_step_execution lb_step_async s ->
weak_fairness lb_step_async label_silent s ->
now (occurred (InputLock c)) s ->
eventually (now (occurred (MsgLock c))) s.