∀ (k : ℤ) (m : Lean.Grind.CommRing.Mon) (p : Lean.Grind.CommRing.Poly),
  Lean.Grind.CommRing.Poly.mulMon_nc k m p =
    bif k == 0 then Lean.Grind.CommRing.Poly.num 0
    else
      bif m == Lean.Grind.CommRing.Mon.unit then Lean.Grind.CommRing.Poly.mulConst k p
      else Lean.Grind.CommRing.Poly.mulMon_nc.go k m p (Lean.Grind.CommRing.Poly.num 0)