{motive : Lean.Expr → Sort u} →
  (t : Lean.Expr) →
    ((typeName : Lean.Name) → (idx : ℕ) → (struct : Lean.Expr) → motive (Lean.Expr.proj typeName idx struct)) →
      (Nat.hasNotBit 2048 t.ctorIdx → motive t) → motive t