proposition: Lemma nth_error_Some_nth {A} (ls : list A) (n : nat) (x : A) : nth_error ls n = Some x -> forall y, nth n ls y = x.
proof: Proof. intros H ?; rewrite nth_error_nth, H; reflexivity. 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