fact: Fixpoint lazy_append' {A : Type} (l1 : LazyList A) (l2 : unit -> LazyList A) : LazyList A := match l1 with | lnil => l2 tt | lcons x l1' => lcons x (fun _ => (lazy_append' (l1' tt) l2)) end.
imports: ExtLib.Structures(Functor Applicative) List QuickChick(Tactics)