proposition: Lemma refold_in : forall {A} a b l, @List.In A a (b :: l) <-> List.In a l \/ a = b.
proof: Proof. intros; simpl; intuition. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Coq.Lists.List Coq.Lists.SetoidList Coq.Bool.Bool Fiat.Common Fiat.Common.List.Operations Fiat.Common.Equality Fiat.Common.List.FlattenList Fiat.Common.LogicFacts