BUG #1796: UNION ALL of NULL <=> type = text so mimack pb

The following bug has been logged online:

Bug reference:      1796
Logged by:          Mansion
Email address:      michael.mansion@u-picardie.fr
PostgreSQL version: 8.0.3
Operating system:   windows XP
Description:        UNION ALL of NULL <=> type = text so mimack pb
Details:

on the table rien with the column "ordre" (int type)
When i write :
INSERT INTO rien (ordre) SELECT NULL UNION ALL SELECT NULL
i have the error :
column "ordre" is of type integer but expression is of type text

Thanks in advance michael From France