Lean.Elab.Do.DoElemCont →
  Option Lean.Elab.Do.ControlStack →
    Option Lean.Elab.Do.ControlStack →
      Option Lean.Elab.Do.ControlStack →
        Lean.Elab.Do.ControlStack → Lean.Elab.Do.CodeLiveness → Lean.Expr → Lean.Elab.Do.ControlLifter