{motive : Lean.Elab.Command.EvalAction✝ → Sort u} →
  (t : Lean.Elab.Command.EvalAction✝¹) →
    ((eval : Lean.Elab.Command.CommandElabM Lean.MessageData) →
        (printVal : Option Lean.Expr) → motive { eval := eval, printVal := printVal }) →
      motive t