{var : String} →
  {α : Type u} →
    {p β : α → Prop} →
      [(x : α) → Plausible.PrintableProp (p x)] →
        [(x : α) → Plausible.Testable (β x)] →
          [Plausible.SampleableExt (Subtype p)] →
            {var' : String} →
              Plausible.Testable (Plausible.NamedBinder var (∀ (x : α), Plausible.NamedBinder var' (p x → β x)))