(** Corollaries of [external_call_determ]. *)

Lemma external_call_match_traces:
forall ef ge vargs m t1 vres1 m1 t2 vres2 m2,
external_call ef ge vargs m t1 vres1 m1 ->
external_call ef ge vargs m t2 vres2 m2 ->
match_traces ge t1 t2.