Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> I think that was me, long ago.
IIRC, BETWEEN is not the only construct that generates multiply-linked
subtrees, so you don't need to take the whole blame ;-)
The copyObject solution has the advantage of being fairly robust,
whereas trying to ban such things in the parser's output would not be.
regards, tom lane