Wrong result with LAST_DAY('0000-00-00 00:00:00') IS NULL in WHERE condition

[Igor Babaev]

The following sequence of commands returns incorrect result in MariaDB 5.2:

CREATE TABLE t1(a INT) ENGINE=InnoDB;
INSERT INTO t1 VALUES(1);
SELECT * FROM t1 WHERE LAST_DAY('0000-00-00 00:00:00') IS NULL;

MariaDB [test]> SELECT * FROM t1 WHERE LAST_DAY('0000-00-00 00:00:00') IS NULL;
Empty set (0.01 sec)

The expected result is:
MariaDB [test]> SELECT * FROM t1 WHERE LAST_DAY('0000-00-00 00:00:00') IS NULL;
+------+
| a |
+------+
| 1 |
+------+

(see also bug #13626019 for mysql)