{α β : Type u_1} →
  {γ : Type u} →
    [inst : Std.Slice.SliceSize γ] →
      [inst_1 : Std.ToIterator (Std.Slice γ) Id α β] →
        [inst_2 : Std.Iterator α Id β] →
          {motive : Std.Slice.LawfulSliceSize γ → Sort u_2} →
            (t : Std.Slice.LawfulSliceSize γ) →
              ((lawful : ∀ (s : Std.Slice γ), Std.Slice.SliceSize.size s = (Std.ToIterator.iter s).length) → motive ⋯) →
                motive t