BUG #4783: new syntax in tablefunction - not output cells

The following bug has been logged online:

Bug reference:      4783
Logged by:          Alex
Email address:      oktogen@mail.ru
PostgreSQL version: 8.4
Operating system:   WinXP
Description:        new syntax in tablefunction - not output cells
Details:

CREATE TABLE tst (
  "id" BIGSERIAL,
  "vl" DOUBLE PRECISION DEFAULT 0 NOT NULL,
  CONSTRAINT "tst_pkey" PRIMARY KEY("id")
) WITHOUT OIDS;

INSERT INTO   tst(id)
VALUES  (1),(2),(2),(2),(2),(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),
(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2),(2);


CREATE OR REPLACE FUNCTION
test1 () RETURNS TABLE(id BIGINT,   vl DOUBLE PRECISION) AS
$body$
BEGIN
  RETURN QUERY
  SELECT
    id,
    vl
  FROM tst;
END
$body$
LANGUAGE 'plpgsql'
IMMUTABLE
CALLED ON NULL INPUT
SECURITY DEFINER
COST 1000 ROWS 1000;

CREATE OR REPLACE FUNCTION
test2 () RETURNS TABLE(id BIGINT,   vl DOUBLE PRECISION) AS
$body$
  SELECT
    id,
    vl
  FROM tst;
END
$body$
LANGUAGE 'sql'
IMMUTABLE
CALLED ON NULL INPUT
SECURITY DEFINER
COST 1000 ROWS 1000;

query SELECT * FROM test1(); return NULL's if
name columns in "RETURN QUERY" = name columns  in
"RETURNS TABLE".

was tested with languages: plpgsql and sql
this is bag or feature?
thank's