∀ {C : Type u_1} [inst : CategoryTheory.Category.{v_1, u_1} C] (r : HomRel C)
  [CategoryTheory.HomRel.IsStableUnderPrecomp r] [CategoryTheory.HomRel.IsStableUnderPostcomp r] {X Y : C}
  (f g : X ⟶ Y), CategoryTheory.HomRel.CompClosure r f g = r f g