Inductive vagree_list: list val -> list val -> list nval -> Prop :=
| vagree_list_nil: forall nvl,
vagree_list nil nil nvl
| vagree_list_default: forall v1 vl1 v2 vl2,
vagree v1 v2 All -> vagree_list vl1 vl2 nil ->
vagree_list (v1 :: vl1) (v2 :: vl2) nil
| vagree_list_cons: forall v1 vl1 v2 vl2 nv1 nvl,
vagree v1 v2 nv1 -> vagree_list vl1 vl2 nvl ->
vagree_list (v1 :: vl1) (v2 :: vl2) (nv1 :: nvl).

Lemma lessdef_vagree_list:
forall vl1 vl2, vagree_list vl1 vl2 nil -> Val.lessdef_list vl1 vl2.