{C : Type u₁} →
  [inst : CategoryTheory.Category.{v₁, u₁} C] →
    {X Y : C} →
      {f : X ⟶ Y} →
        {motive : CategoryTheory.IsSplitMono f → Sort u} →
          ((exists_splitMono : Nonempty (CategoryTheory.SplitMono f)) → motive ⋯) →
            (t : CategoryTheory.IsSplitMono f) → motive t