proposition: Lemma binds_one_iff : binds x a (y ~ b) <-> x = y /\ a = b.
proof: Proof. clear. intuition auto using binds_one_1, binds_one_2, binds_one_3. 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