BUG #4710: Bug with sql functions, when using INSERT.. RETURNING .. statment

The following bug has been logged online:

Bug reference: 4710
Logged by: Oleg
Email address: serovOv@gmail.com
PostgreSQL version: last stable
Operating system: CentOS
Description: Bug with sql functions, when using INSERT.. RETURNING ..
statment
Details:

Example:

CREATE TABLE test (id BIGINT);
CREATE OR REPLACE FUNCTION test(in_row test) RETURNS bigint AS
$body$
INSERT INTO test (SELECT $1.*) RETURNING id;
$body$
LANGUAGE 'sql';

WILL THROW:

ERROR: return type mismatch in function declared to return bigint
DETAIL: Function's final statement must be a SELECT.
CONTEXT: SQL function "test"

It is okey ?