I wrote:
> It kind of feels that the argument order should be pointer, oldsize, size.
> It feels even more strongly that people will get the ordering wrong,
> whichever we choose. Is there a way to make that more bulletproof?
Actually ... an even-more-terrifyingly-plausible misuse is that the
supplied oldsize is different from the actual previous allocation.
We should try to check that. In MEMORY_CONTEXT_CHECKING builds
it should be possible to assert that oldsize == requested_size.
We don't have that data if !MEMORY_CONTEXT_CHECKING, but we could
at least assert that oldsize <= allocated chunk size.
regards, tom lane