Proof (proj1 (proj2 bigstep_to_steps)).

Lemma eval_exprlist_to_steps:
forall e m al t m' al',
eval_exprlist e m al t m' al' ->
forall a1 al2 ty C f k, leftcontext RV RV C -> simple a1 = true -> simplelist al2 = true ->
simplelist al' = true /\
star step ge (ExprState f (C (Ecall a1 (exprlist_app al2 al) ty)) k e m)
t (ExprState f (C (Ecall a1 (exprlist_app al2 al') ty)) k e m').