BUG #2483: Wrong error report about missing entry in from clause

The following bug has been logged online:

Bug reference:      2483
Logged by:          Klaus Guntermann
Email address:      guntermann.kl@pvw.tu-darmstadt.de
PostgreSQL version: 8.1.4
Operating system:   Linux
Description:        Wrong error report about missing entry in from clause
Details:

Hi,
with the following simplified example I get a false error message in the
second select statement, which is almost like the first one. The german text
of the error message is:
FEHLER:  fehlender Eintrag in FROM-Klausel für Tabelle »dummy«
The difference is that in the second statement all columns are qualified by
the table name.
The example is simplified from a larger select and normally one would not
phrase the selection this way. But nevertheless I think both versions of the
statement should work.
Thank you very much for your work on PostgreSQL!
Best regards,
Klaus

8<------------------- cut here
create temporary table dummy (myfield integer);
insert into dummy (myfield) values (1);
insert into dummy (myfield) values (2);

select myfield from dummy where myfield=1 union
select myfield from dummy where myfield=2 order by myfield;

select dummy.myfield from dummy where dummy.myfield=1 union
select dummy.myfield from dummy where dummy.myfield=2 order by
dummy.myfield;
8<------------------- cut here