Condition pushdown into derived table doesn't work if select list uses SP

create function myfunc(a int) returns int DETERMINISTIC return (a+1);

create table t1 (

  pk int primary key,

  a int,

  b int,

  key(a)

);

insert into t1 select seq,seq,seq from seq_1_to_1000;

create view v1 as 

select

  t1.a as col1,

  myfunc(t1.b) as col2

from

  t1;

create view v2 as 

select

  t1.a as col1,

  myfunc(t1.b) as col2

from

  t1;

create view v3 as 

select col2, col1 from v1

union all

select col2, col1 from v2;

explain select * from v3 where col1=123;

+------+-------------+------------+------+---------------+------+---------+-------+------+-------------+

| id   | select_type | table      | type | possible_keys | key  | key_len | ref   | rows | Extra       |

+------+-------------+------------+------+---------------+------+---------+-------+------+-------------+

|    1 | PRIMARY     | <derived2> | ALL  | NULL          | NULL | NULL    | NULL  | 2    | Using where |

|    2 | DERIVED     | t1         | ref  | a             | a    | 5       | const | 1    |             |

|    3 | UNION       | t1         | ref  | a             | a    | 5       | const | 1    |             |

+------+-------------+------------+------+---------------+------+---------+-------+------+-------------+

explain select * from v3 where col1=123 and col2=321;

+------+-------------+------------+------+---------------+------+---------+------+------+-------------+

| id   | select_type | table      | type | possible_keys | key  | key_len | ref  | rows | Extra       |

+------+-------------+------------+------+---------------+------+---------+------+------+-------------+

|    1 | PRIMARY     | <derived2> | ALL  | NULL          | NULL | NULL    | NULL | 2000 | Using where |

|    2 | DERIVED     | t1         | ALL  | NULL          | NULL | NULL    | NULL | 1000 |             |

|    3 | UNION       | t1         | ALL  | NULL          | NULL | NULL    | NULL | 1000 |             |

+------+-------------+------------+------+---------------+------+---------+------+------+-------------+