Opaque smash'_e.
Definition smash_e : BC :=
rec2 (comp 1 0 (succ true) nil [zero_e 1 0])
(comp 2 1 smash'_e [proj 2 0 1] [proj 2 1 2]).
(* Eval vm_compute in arities smash_e. *)

(* Specifications: *)
Lemma smash_correct x y :
sem smash_e [x;y] nil = smash_bs x y.