proposition: Lemma lazylist_backtrack_opt_is_true A (l: LazyList.LazyList (option A)) ch b : lazylist_backtrack_opt l ch true = Some b -> b = true.
proof: Proof. induction l. - simpl. congruence. - simpl in *. destruct a. + destruct (ch a) eqn:Heq. destruct b0. congruence. now eauto. now eauto. + eauto. Qed.
imports: Coq.Classes.Morphisms mathcomp.ssreflect.ssreflect mathcomp(ssrbool ssrnat) Sets Tactics Recdef List ZArith ZArith.Znat Arith Producer Generators Enumerators