(* From Undecidability Require Import Combinators.Combinators Multi Basic.Mono TMTac. *)
Local Set Printing Coercions.
(* Avoid using [Vector.to_list], because it doesn't [cbn] good. Use [vector_to_list] instead. *)
Local Arguments Vector.to_list {A n} (!v).
Local Arguments plus : simpl never.
Local Arguments mult : simpl never.

Lemma removelast_cons (X : Type) (xs : list X) (x : X) :
xs <> nil ->
removelast (x :: xs) = x :: removelast xs.