End Properties.
Hint Rewrite @subst0_id : open.
Hint Rewrite @substl_subst1 : open.
Hint Rewrite @substl_trunc_notin using assumption : open.
Section MoreLemmas.
Context {A val : Type} {Heq : RelDec (@eq A)} {HeqOk : RelDec_Correct Heq}.
Context {R : ValNull val}.
Open Scope open_scope.

Lemma val_expr_substs : forall (v : val) es,
((V_expr v) // es) = (V_expr v).