{motive : Lean.Elab.Command.Structure.StructFieldDefault → Sort u} →
  (t : Lean.Elab.Command.Structure.StructFieldDefault) →
    ((value : Lean.Expr) → motive (Lean.Elab.Command.Structure.StructFieldDefault.optParam value)) →
      (Nat.hasNotBit 1 t.ctorIdx → motive t) → motive t