{α : Type u} →
  [inst : Std.PRange.UpwardEnumerable α] →
    {motive : Std.Rxi.IsAlwaysFinite α → Sort u_1} →
      ((finite : ∀ (init : α), ∃ n, Std.PRange.succMany? n init = none) → motive ⋯) →
        (t : Std.Rxi.IsAlwaysFinite α) → motive t