Cannot insert into temp tables

I mentioned this the other day on another list. I want to reiterate it
here because I can't seem to get anywhere.

I create a temporary table
=> create temp table foo (bar text);
CREATE
=> insert into foo values ('hi');
ERROR: pg_temp.29112.0: Permission denied.

This apparently happens if and only if the user that executes this has
pg_shadow.usecatupd = 'f'.

I have tried this with the 6.5.1 source rpm bundle, fresh after initdb and
also with a 6.5.0 tar ball installation -- same result. (both on RH Linux
5.2-ish)

A potential reason that this has gone unnoticed so far is that when you
create a user thus:
=> create user joe;
the usecatupd defaults to true (why?).

Also this does not have anything to do with superuser status, the ability
to create and use regular tables, the ability to create databases, the
datatypes in the temp table, any hba stuff, or anything else I could think
of.

Anyone got a clue?

Regards,
Peter

--
Peter Eisentraut
PathWay Computing, Inc.