∀ (α : Type u_1) [inst : Encodable α] (x : ℕ) (motive : x ∈ Set.range Encodable.encode → Prop)
  (x_1 : x ∈ Set.range Encodable.encode), (∀ (n : α) (hn : Encodable.encode n = x), motive ⋯) → motive x_1