(motive : Option ℕ → Option ℕ → Sort u_1) →
  (trailPrec x : Option ℕ) →
    ((trailPrec contPrec : ℕ) → motive (some trailPrec) (some contPrec)) →
      ((x x_1 : Option ℕ) → motive x x_1) → motive trailPrec x