∀ {α : Type u_1} {β : α → Type u_2} [inst : (a : α) → Fintype (β a)] [inst_1 : (a : α) → Encodable (β a)]
  (x : WType.WType'✝ β 0),
  (fun x => Empty.casesOn (fun t => x = t → WType.WType'✝¹ β 0) x ⋯)
      ((fun x =>
          match x with
          | ⟨val, h⟩ => ⋯.elim)
        x) =
    x