proposition: Lemma binds_cons_1 : binds x a ((VarAsn B y b) :: E) -> (x = y /\ a = b) \/ binds x a E.
proof: Proof. clear. inversion 1 as [J | J]; try injection J; auto. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics