{m : Type w → Type w'} →
  {β : Type w} →
    {P : Sort u} →
      {α : Type w} →
        {inst : Std.Iterator α m β} →
          {iterator : Std.IterM m β} →
            {α' : Type w} →
              {inst' : Std.Iterator α' m β} →
                {iterator' : Std.IterM m β} →
                  { α := α, inst := inst, iterator := iterator } = { α := α', inst := inst', iterator := iterator' } →
                    (α = α' → inst ≍ inst' → iterator ≍ iterator' → P) → P