∀ {J : Type u_1} [inst : CategoryTheory.Category.{u_4, u_1} J] {C : Type u_2}
  [inst_1 : CategoryTheory.Category.{u_3, u_2} C] {F : CategoryTheory.Functor J C} {t : CategoryTheory.Limits.Cocone F},
  (CategoryTheory.CategoryStruct.comp (fun h => { desc := fun s => default.hom, fac := ⋯, uniq := ⋯ }) fun h s =>
      { default := h.descCoconeMorphism s, uniq := ⋯ }) =
    CategoryTheory.CategoryStruct.id ((s : CategoryTheory.Limits.Cocone F) → Unique (t ⟶ s))