proposition: Lemma env_eq_some_nil_absurd : forall E1 A, Some A :: E1 [=] EmptyEnv -> False.
proof: Proof. intros. set (w := (proj1 H) 0 A); compute in w. set (p := w (eq_refl (Some (Some A)))); inversion p. Qed.
imports: CoLoR(RelExtras ListExtras TermsLifting LogicUtil OptUtil) Coq(Arith Setoid Morphisms Lia)