∀ {J : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} J] {α : Type u_3}
  (F : CategoryTheory.Functor J (CategoryTheory.Discrete α)) {X Y Z : J} (f : X ⟶ Y) (g : Y ⟶ Z),
  (have this := ⋯;
    { down := { down := ⋯ } }) =
    CategoryTheory.CategoryStruct.comp
      (have this := ⋯;
      { down := { down := ⋯ } })
      (have this := ⋯;
      { down := { down := ⋯ } })