proposition: Lemma binds_cons_1 : binds x a ((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 Coq.Strings.String String Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.CoqFSetInterface Coq.Classes.Equivalence Coq.Classes.EquivDec Metalib.CoqEqDec