BUG #6036: why a REAL should be queried as a string?

The following bug has been logged online:

Bug reference: 6036
Logged by: jose soares
Email address: jose(dot)soares(at)sferacarta(dot)com
PostgreSQL version: 8.4.4
Operating system: x86_64-pc-linux-gnu
Description: why a REAL should be queried as a string?
Details:

I'd like to to report this strange behavior, that I think is a bug...

# \d frazione
Table "public.frazione"
Column | Type | Modifiers
------------+---------+--------------------
id | integer | not null
importo | real | not null

# update frazione set importo=0.833 where id=549;
UPDATE 1
# select * from frazione where importo=0.833;
id | importo
----+---------
(0 rows)

# select * from frazione where importo='0.833';
id | importo
-----+----------
549 | 0.833
(1 rows)