∀ {α : Type u_1} (motive : (x : List α) → x ≠ [] → Sort u_2) (a : α) (tail : List α) (x : a :: tail ≠ [])
  (h_1 : (a : α) → (tail : List α) → (x : a :: tail ≠ []) → motive (a :: tail) x),
  (match a :: tail, x with
    | a :: tail, x => h_1 a tail x) =
    h_1 a tail x