∀ {a : Lean.Widget.WidgetInstance} {a_1 : Lean.MessageData} {a_2 : Lean.Widget.WidgetInstance} {a_3 : Lean.MessageData},
  Lean.MessageData.ofWidget a a_1 = Lean.MessageData.ofWidget a_2 a_3 → a = a_2 ∧ a_1 = a_3