(s : ByteSlice) →
  (motive : (i : ℕ) → i ≤ s.size → Sort u_1) →
    (i : ℕ) →
      (h : i ≤ s.size) →
        ((x : 0 ≤ s.size) → motive 0 x) → ((i : ℕ) → (h : i + 1 ≤ s.size) → motive i.succ h) → motive i h