∀ {R : Type u_3} {A : Type u_1} {C : Type u_2} [inst : CommSemiring R] [inst_1 : Ring A] [inst_2 : AddCommMonoid C]
  [inst_3 : Algebra R A] [inst_4 : Module R C] (n : ℕ) (a : WithConv (C →ₗ[R] A)),
  SubNegMonoid.zsmul (Int.negSucc n) a = -SubNegMonoid.zsmul (↑n.succ) a