{motive : Lean.Elab.Term.Op.Tree✝ → Sort u} →
  (t : Lean.Elab.Term.Op.Tree✝¹) →
    Lean.Elab.Term.Op.Tree.ctorIdx✝ t = 2 →
      ((ref : Lean.Syntax) →
          (f : Lean.Expr) → (arg : Lean.Elab.Term.Op.Tree✝²) → motive (Lean.Elab.Term.Op.Tree.unop✝ ref f arg)) →
        motive t