It&#x27;s very hard to be aware of the numerous details you find obvious yourself when you&#x27;re communicating.<p>Also, by the way, I have an intuition that the issue might not specifically prevent the removal of a reverse operation. That is to say, if a series with some positives or negative integers does&#x2F;doesn&#x27;t overflow under a left fold, I have a hunch that it does&#x2F;doesn&#x27;t under a right fold.<p>If this can be proven, then that specific case is fine over integers (optimizing away reverse).