This query:

SELECT *
FROM t1, t2
WHERE t2.b IN (
        SELECT 'm' UNION
        SELECT 'm'
) OR t1.b <> SOME (
        SELECT 'v' UNION
        SELECT 't'
);

crashes as follows:

#4 <signal handler called>
#5 0x0824c373 in subselect_union_engine::no_rows (this=0xae514c20) at item_subselect.cc:2703
#6 0x0820ec2e in Item_in_optimizer::val_int (this=0xae52ba18) at item_cmpfunc.cc:1701
#7 0x081e2706 in Item::val_int_result (this=0xae52ba18) at item.h:839
#8 0x081dd848 in Item_cache_int::cache_value (this=0xae565b38) at item.cc:8209
#9 0x081e67d2 in Item_cache_wrapper::cache (this=0xae565ac0) at item.cc:7056
#10 0x081dac96 in Item_cache_wrapper::val_int (this=0xae565ac0) at item.cc:7110
#11 0x0820bab4 in Item_func_nop_all::val_int (this=0xae514c40) at item_cmpfunc.cc:401
#12 0x081ca95c in Item::val_bool (this=0xae514c40) at item.cc:197
#13 0x082170b6 in Item_cond_or::val_int (this=0xae52cae0) at item_cmpfunc.cc:4514
#14 0x082f6b52 in SQL_SELECT::skip_record (this=0xae52cb90, thd=0x9edb6e0) at opt_range.h:922
#15 0x082f7749 in JOIN_CACHE::check_match (this=0xae52ce08, rec_ptr=0xae5452d8 "\377\377\002") at sql_join_cache.cc:2422
#16 0x082f3c10 in JOIN_CACHE::generate_full_extensions (this=0xae52ce08, rec_ptr=0xae5452d8 "\377\377\002") at sql_join_cache.cc:2365
#17 0x082f3a19 in JOIN_CACHE::join_matching_records (this=0xae52ce08, skip_last=false) at sql_join_cache.cc:2265
#18 0x082f34d9 in JOIN_CACHE::join_records (this=0xae52ce08, skip_last=false) at sql_join_cache.cc:2062
#19 0x0833dca5 in sub_select_cache (join=0xae526020, join_tab=0xae52c668, end_of_records=true) at sql_select.cc:14913
#20 0x0833debd in sub_select (join=0xae526020, join_tab=0xae52c468, end_of_records=true) at sql_select.cc:15075
#21 0x0833d9ac in do_select (join=0xae526020, fields=0x9edd1b4, table=0x0, procedure=0x0) at sql_select.cc:14797
#22 0x08322206 in JOIN::exec (this=0xae526020) at sql_select.cc:2679
#23 0x08322a32 in mysql_select (thd=0x9edb6e0, rref_pointer_array=0x9edd25c, tables=0xae5130c0, wild_num=1, fields=..., conds=0xae514cd0, og_num=0,
    order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2147764736, result=0xae514df0, unit=0x9edce40, select_lex=0x9edd120)
    at sql_select.cc:2900
#24 0x0831a92f in handle_select (thd=0x9edb6e0, lex=0x9edcde4, result=0xae514df0, setup_tables_done_option=0) at sql_select.cc:283
#25 0x082b5050 in execute_sqlcom_select (thd=0x9edb6e0, all_tables=0xae5130c0) at sql_parse.cc:5112
#26 0x082abe0d in mysql_execute_command (thd=0x9edb6e0) at sql_parse.cc:2250
#27 0x082b7691 in mysql_parse (thd=0x9edb6e0,
    rawbuf=0xae512ec0 "SELECT *\nFROM t1, t2\nWHERE t2.b IN (\nSELECT 'm' UNION\nSELECT 'm'\n) OR t1.b <> SOME (\nSELECT 'v' UNION\nSELECT 't'\n)",
    length=114, found_semicolon=0xae883228) at sql_parse.cc:6113
#28 0x082a9a5c in dispatch_command (command=COM_QUERY, thd=0x9edb6e0, packet=0x9f34571 "", packet_length=114) at sql_parse.cc:1221
#29 0x082a8eb7 in do_command (thd=0x9edb6e0) at sql_parse.cc:916
#30 0x082a5e9b in handle_one_connection (arg=0x9edb6e0) at sql_connect.cc:1191
#31 0x00821919 in start_thread () from /lib/libpthread.so.0
#32 0x0076acce in clone () from /lib/libc.so.6

minimal switch: join_cache_level=3
full switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=on,loosescan=on,materialization=off,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on

explain:

id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
4 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
5 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union4,5> ALL NULL NULL NULL NULL NULL
2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used
3 DEPENDENT UNION NULL NULL NULL NULL NULL NULL NULL No tables used
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL

 bzr version-info
revision-id: <email address hidden>
date: 2011-11-07 16:39:02 +0400
build-date: 2011-11-08 10:15:29 +0200
revno: 3273
branch-nick: maria-5.3

test case:

CREATE TABLE t2 ( a int, b varchar(1)) ;
INSERT IGNORE INTO t2 VALUES (8,'y'),(8,'y');

CREATE TABLE t1 ( b varchar(1)) ;
INSERT IGNORE INTO t1 VALUES (NULL),(NULL);

SET SESSION join_cache_level=3;

SELECT *
FROM t1, t2
WHERE t2.b IN (
        SELECT 'm' UNION
        SELECT 'm'
) OR t1.b <> SOME (
        SELECT 'v' UNION
        SELECT 't'
);

see also bug https://bugs.launchpad.net/maria/+bug/885162