mysqld: item.cc:9058: void Item_type_holder::get_full_info(Item*): Assertion `(enum_set_typelib && get_real_type(item) == MYSQL_TYPE_NULL) || (!enum_set_typelib && item->type() == Item::FIELD_ITEM && (get_real_type(item) == MYSQL_TYPE_ENUM || get_real_type(item) == MYSQL_TYPE_SET) && ((Field_enum*)((Item_field *) item)>field)>typelib)' failed

#8 0xb74b7014 in __assert_fail () from /lib/libc.so.6
#9 0x08210492 in Item_type_holder::get_full_info (this=0x945f380,
item=0x945f290) at item.cc:9052
#10 0x0820f7da in Item_type_holder::Item_type_holder (this=0x945f380,
thd=0x93edad0, item=0x945f290) at item.cc:8712
#11 0x084b08af in st_select_lex_unit::prepare (this=0x93ef240,
thd_arg=0x93edad0, sel_result=0x945f178, additional_options=268435456)
at sql_union.cc:339
#12 0x084afac6 in mysql_union (thd=0x93edad0, lex=0x93ef1e4, result=0x945f178,
unit=0x93ef240, setup_tables_done_option=1073741824) at sql_union.cc:33
#13 0x08350a3c in handle_select (thd=0x93edad0, lex=0x93ef1e4,
result=0x945f178, setup_tables_done_option=1073741824) at sql_select.cc:262
#14 0x082e6252 in mysql_execute_command (thd=0x93edad0) at sql_parse.cc:3301
#15 0x082ee6d3 in mysql_parse (thd=0x93edad0,
rawbuf=0x945d4f0 "INSERT INTO t3 SELECT * FROM ( SELECT * FROM t1 ) AS A UNION SELECT * FROM t2", length=77, found_semicolon=0xae930234)
at sql_parse.cc:6149
#16 0x082e10d6 in dispatch_command (command=COM_QUERY, thd=0x93edad0,
packet=0x9447361 "INSERT INTO t3 SELECT * FROM ( SELECT * FROM t1 ) AS A UNION SELECT * FROM t2", packet_length=77) at sql_parse.cc:1227
#17 0x082e0580 in do_command (thd=0x93edad0) at sql_parse.cc:922
#18 0x082dd545 in handle_one_connection (arg=0x93edad0) at sql_connect.cc:1193
#19 0xb7745b25 in start_thread () from /lib/libpthread.so.0

bzr version-info
revision-id: <email address hidden>
date: 2012-01-25 22:05:20 +0400
build-date: 2012-01-26 03:37:01 +0400
revno: 3395
branch-nick: maria-5.3

Also fails on MariaDB-5.5.
Could not reproduce on MariaDB-5.2, MySQL-5.1, 5.5, 5.6.

Test case:

CREATE TABLE t1 ( a ENUM( 'x', 'y' ) );
CREATE TABLE t2 LIKE t1;
CREATE TABLE t3 LIKE t1;
INSERT INTO t3
SELECT * FROM ( SELECT * FROM t1 ) AS A
UNION SELECT * FROM t2;