Empty variable names allowed and break replication

The original description can be found further in this field

The problem is reproducible with MySQL 5.1-5.6 and filed as http://bugs.mysql.com/bug.php?id=68135.

A variable can be created with an empty name. Apparently, it's confusing (see the original request below) and potentially error-prone; but it also causes problems with binary logging and replication:

SET @`` = 1;

CREATE TABLE t1 AS SELECT @`` AS f;

SHOW BINLOG EVENTS;

ERROR HY000: Error when executing command SHOW BINLOG EVENTS: Wrong offset or I/O error

Consequently, replication fails with ER_SLAVE_RELAY_LOG_READ_FAILURE.

Currently it's only reproducible on maria/5.5, but not on maria/5.1, 5.2, 5.3 or 10.0-base. However, I suppose it's just a matter of time, since it came to maria/5.5 with the last mysql-5.1.67 merge, and it exists in all current trees of MySQL.

Test case:

--source include/master-slave.inc

--source include/have_binlog_format_statement.inc

SET @`` = 1;

CREATE TABLE t1 AS SELECT @`` AS f;

--sync_slave_with_master

==================================

Original description

I'm not sure if this is a bug or a feature request. Empty names seem to be allowed for variables. No warnings.
Empty names are not allowed for schemas, tables, columns, views, etc.

MariaDB [test]> SET @`` = 1;

Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> SELECT @``;

+------+

| @``  |

+------+

|    1 |

+------+

1 row in set (0.07 sec)

MariaDB [test]>

The same happens with local vars in stored routines:

DROP FUNCTION IF EXISTS `test`;

CREATE FUNCTION `test`()

	RETURNS BOOLEAN

BEGIN

	DECLARE `` TINYINT UNSIGNED;

	SET `` = 1;

	RETURN ``;

END;