proposition: Lemma binds_dom_contradiction : forall (E : list (X.t*A)), binds x a E -> ~ In x (dom E) -> False.
proof: Proof. clear. intros E H1 H2. alist induction E as [ | ? ? ? IH ]. inversion H1. unfold binds in *. simpl in *. destruct H1 as [J | J]. injection J. fsetdec. eapply IH. auto. fsetdec. 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