{P : Sort u} →
  {name : Lean.Name} →
    {p₁ p₂ : Lean.ParserDescr} →
      {name' : Lean.Name} →
        {p₁' p₂' : Lean.ParserDescr} →
          Lean.ParserDescr.binary name p₁ p₂ = Lean.ParserDescr.binary name' p₁' p₂' →
            (name = name' → p₁ = p₁' → p₂ = p₂' → P) → P