∀ {C : Type u} [inst : CategoryTheory.Category.{v, u} C] [inst_1 : CategoryTheory.Limits.HasFiniteProducts C]
  [inst_2 : CategoryTheory.Limits.HasPullbacks C] (X x x_1 : CategoryTheory.Dial C) (f : x ⟶ x_1),
  (CategoryTheory.MonoidalCategoryStruct.whiskerLeft X f).f =
    CategoryTheory.Limits.prod.map (CategoryTheory.CategoryStruct.id X.src) f.f