prepare parse panic

[siddontang]

CREATE TABLE `t1` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY  (`a`,`b`,`c`)) ENGINE=InnoDB;
CREATE TABLE `t2` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY  (`a`,`b`,`c`)) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1,1,1);
INSERT INTO t2 VALUES (1,1,1);
PREPARE my_stmt FROM "SELECT t1.b, count(*) FROM t1 group by t1.b having
count(*) > ALL (SELECT COUNT(*) FROM t2 WHERE t2.a=1 GROUP By t2.b)";
EXECUTE my_stmt;
EXECUTE my_stmt;
deallocate prepare my_stmt;
drop table t1,t2;

It will raise panic when we run EXECUTE this prepare statement.