∀ {C : Type u_2} [inst : CategoryTheory.Category.{u_1, u_2} C] {X Y : C} (c : CategoryTheory.Limits.BinaryCofan X Y)
  (l : CategoryTheory.Limits.WalkingPair),
  CategoryTheory.CategoryStruct.comp (c.ι.app { as := l }) (CategoryTheory.Iso.refl c.pt).hom =
    (CategoryTheory.Limits.BinaryCofan.mk c.inl c.inr).ι.app { as := l }