BUG #2980: check constraint fails on update

The following bug has been logged online:

Bug reference: 2980
Logged by: Walter Cruz
Email address: walter(dot)php(at)gmail(dot)com
PostgreSQL version: 8.1.7
Operating system: Linux
Description: check constraint fails on update
Details:

Hi All. A simple table to test:

CREATE TABLE simples
(
coluna varchar(10)
)
WITHOUT OIDS;

ALTER TABLE simples
ADD CONSTRAINT simples_coluna_check CHECK (coluna::text = 'girafa'::text
OR coluna::text = 'bode'::text);

INSERT INTO simples (coluna) VALUES ('girafa');
(ok)

INSERT INTO simples (coluna) VALUES ('bode');
(ok)

INSERT INTO simples (coluna) VALUES ('macaco'); (violates constraints, ok).

UPDATE simples set coluna = 'girafa';

FAILS!

ERROR: attribute 1 has wrong type
DETAIL: Table has type character varying, but query expects character
varying.

"PostgreSQL 8.1.7 on i486-pc-linux-gnu, compiled by GCC cc (GCC) 4.1.2
20061115 (prerelease) (Debian 4.1.1-21)"

Works with 8.1.3 windows, 8.1.4 ubuntu, 8.2 windows.