∀ {α : Type u_1} (motive : List α → List α → Sort u_2) (x x_1 : List α) (h_1 : (acc : List α) → motive [] acc)
  (h_2 : (a : α) → (t acc : List α) → motive (a :: t) acc) (a : α) (t acc : List α),
  x = a :: t →
    x_1 = acc →
      (match x, x_1 with
        | [], acc => h_1 acc
        | a :: t, acc => h_2 a t acc) ≍
        h_2 a t acc