Theorem: Category.whisker_eq (CategoryTheory/Basic.lean)

State before:
α : Type u_2
β : Type ?u.23211
γ : Type ?u.23214
δ : Type ?u.23217
A B C D : α
inst✝³ : Category α
inst✝² : Category β
inst✝¹ : Category γ
inst✝ : Category δ
h : B ⟶ C
f g : A ⟶ B
w : f = g
⊢ h ∘ f = h ∘ g
Tactic:
rw [w]
State after:
no goals