∀ {v : Lean.Level} {M : Q(Type v)} (iM : Q(CommGroupWithZero «$M»))
  (_x : (_ : Mathlib.Tactic.FieldSimp.qNF M) ×' Mathlib.Tactic.FieldSimp.qNF M),
  Mathlib.Tactic.FieldSimp.qNF.mkDivProof._unary iM _x =
    PSigma.casesOn _x fun l₁ l₂ =>
      match l₁, l₂ with
      | [], l =>
        have a := l.toNF;
        q(⋯)
      | l, [] =>
        have a := l.toNF;
        q(⋯)
      | ((a₁, x₁), k₁) :: t₁, ((a₂, x₂), k₂) :: t₂ =>
        if k₁ > k₂ then
          have pf := Mathlib.Tactic.FieldSimp.qNF.mkDivProof._unary iM ⟨t₁, ((a₂, x₂), k₂) :: t₂⟩;
          q(⋯)
        else
          if k₁ = k₂ then
            have pf := Mathlib.Tactic.FieldSimp.qNF.mkDivProof._unary iM ⟨t₁, t₂⟩;
            q(⋯)
          else
            have pf := Mathlib.Tactic.FieldSimp.qNF.mkDivProof._unary iM ⟨((a₁, x₁), k₁) :: t₁, t₂⟩;
            q(⋯)