I wrote:
> The other cases that I found involve cidrcol, and seem to represent
> an actual bug in the brin planning logic, ie failure to disregard a
> no-op cast. I'll look closer.
I leapt to the wrong conclusion on that one. The reason for failure to
match to an index column had nothing to do with the extra cast, and
everything to do with the fact that there was no such index column.
I think we're probably good now, though it'd be wise to keep an eye on
chipmunk for awhile to verify that it doesn't see the problem anymore.
regards, tom lane