the '::' cast doesn't work in the FROM clause

Hello,

The following statement produces an error message in PostgreSQL 8.4 - 9.2 (head):

postgres=# select val from random()::integer as val;
ERROR: syntax error at or near "::"
LINE 1: select val from random()::integer as val;

The same statement rewritten with CAST AS works as expected:
^
postgres=# select val from CAST(random() as integer) as val;
val
-----
1
(1 row)

The '::' cast works normally when used in a target list:

postgres=# select random()::integer as val;
val
--------
1
(1 row)

The documentation says these casts are equivalent, so either that's wrong, or this is a bug.
The target OS is Mac OS X 10.7.1 with llvm-gcc-4.2 used as a compiler.

--
Alexey Klyukin http://www.commandprompt.com
The PostgreSQL Company – Command Prompt, Inc.