Server crashes in ha_myisam::index_read_map with index_merge_sort_intersection=on

CREATE TABLE t (pk INT, a INT, PRIMARY KEY(pk), KEY(a)) ENGINE=MyISAM;

INSERT INTO t VALUES (1,NULL),(2,NULL),(3,1),(4,5);

SET optimizer_switch='index_merge_sort_intersection=on';

SELECT pk FROM t WHERE pk > 2 AND a IS NULL;

# Cleanup

DROP TABLE t;

#3  <signal handler called>

#4  handler_rowid_filter_check (h_arg=0x7f8010042a20) at /data/src/bb-11.0/sql/handler.cc:6953

#5  0x0000555f4b165125 in mi_check_index_tuple_real (info=0x7f8010213fc8, keynr=0, record=0x7f8010042598 "\377\003") at /data/src/bb-11.0/storage/myisam/mi_key.c:557

#6  0x0000555f4b1968c2 in mi_check_index_tuple (info=0x7f8010213fc8, keynr=0, record=0x7f8010042598 "\377\003") at /data/src/bb-11.0/storage/myisam/myisamdef.h:752

#7  0x0000555f4b196f05 in mi_rkey (info=0x7f8010213fc8, buf=0x7f8010042598 "\377\003", inx=0, key=0x7f80100193a8 "\002", keypart_map=1, search_flag=HA_READ_AFTER_KEY) at /data/src/bb-11.0/storage/myisam/mi_rkey.c:122

#8  0x0000555f4b1419fb in ha_myisam::index_read_map (this=0x7f8010042a20, buf=0x7f8010042598 "\377\003", key=0x7f80100193a8 "\002", keypart_map=1, find_flag=HA_READ_AFTER_KEY) at /data/src/bb-11.0/storage/myisam/ha_myisam.cc:2009

#9  0x0000555f4a99bfc1 in handler::ha_index_read_map (this=0x7f8010042a20, buf=0x7f8010042598 "\377\003", key=0x7f80100193a8 "\002", keypart_map=1, find_flag=HA_READ_AFTER_KEY) at /data/src/bb-11.0/sql/handler.cc:3617

#10 0x0000555f4a9a535a in handler::read_range_first (this=0x7f8010042a20, start_key=0x7f8010042b28, end_key=0x0, eq_range_arg=false, sorted=false) at /data/src/bb-11.0/sql/handler.cc:6757

#11 0x0000555f4a80e17f in handler::multi_range_read_next (this=0x7f8010042a20, range_info=0x7f802256d068) at /data/src/bb-11.0/sql/multi_range_read.cc:567

#12 0x0000555f4a80e24f in Mrr_simple_index_reader::get_next (this=0x7f8010043098, range_info=0x7f802256d068) at /data/src/bb-11.0/sql/multi_range_read.cc:604

#13 0x0000555f4a810c7a in DsMrr_impl::dsmrr_next (this=0x7f8010042f48, range_info=0x7f802256d068) at /data/src/bb-11.0/sql/multi_range_read.cc:1704

#14 0x0000555f4b1436fc in ha_myisam::multi_range_read_next (this=0x7f8010042a20, range_info=0x7f802256d068) at /data/src/bb-11.0/storage/myisam/ha_myisam.cc:2657

#15 0x0000555f4a4b21a0 in QUICK_RANGE_SELECT::get_next (this=0x7f8010061770) at /data/src/bb-11.0/sql/opt_range.cc:13073

#16 0x0000555f4a4b10b5 in read_keys_and_merge_scans (thd=0x7f8010000db8, head=0x7f8010227668, quick_selects=..., pk_quick_select=0x0, read_record=0x7f80102205d0, intersection=true, filtered_scans=0x7f8010220670, unique_ptr=0x7f8010220560) at /data/src/bb-11.0/sql/opt_range.cc:12621

#17 0x0000555f4a4b1591 in QUICK_INDEX_INTERSECT_SELECT::read_keys_and_merge (this=0x7f8010220520) at /data/src/bb-11.0/sql/opt_range.cc:12738

#18 0x0000555f4a496b1d in QUICK_INDEX_SORT_SELECT::reset (this=0x7f8010220520) at /data/src/bb-11.0/sql/opt_range.cc:1403

#19 0x0000555f4a68e94c in join_init_read_record (tab=0x7f8010062ca0) at /data/src/bb-11.0/sql/sql_select.cc:23488

#20 0x0000555f4a68c743 in sub_select (join=0x7f8010017230, join_tab=0x7f8010062ca0, end_of_records=false) at /data/src/bb-11.0/sql/sql_select.cc:22518

#21 0x0000555f4a68be36 in do_select (join=0x7f8010017230, procedure=0x0) at /data/src/bb-11.0/sql/sql_select.cc:22066

#22 0x0000555f4a65cece in JOIN::exec_inner (this=0x7f8010017230) at /data/src/bb-11.0/sql/sql_select.cc:4849

#23 0x0000555f4a65c019 in JOIN::exec (this=0x7f8010017230) at /data/src/bb-11.0/sql/sql_select.cc:4627

#24 0x0000555f4a65d6ec in mysql_select (thd=0x7f8010000db8, tables=0x7f8010015b28, fields=..., conds=0x7f80100167e8, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2164525824, result=0x7f8010017208, unit=0x7f80100051e0, select_lex=0x7f8010015548) at /data/src/bb-11.0/sql/sql_select.cc:5107

#25 0x0000555f4a64da61 in handle_select (thd=0x7f8010000db8, lex=0x7f8010005108, result=0x7f8010017208, setup_tables_done_option=0) at /data/src/bb-11.0/sql/sql_select.cc:608

#26 0x0000555f4a5fdb49 in execute_sqlcom_select (thd=0x7f8010000db8, all_tables=0x7f8010015b28) at /data/src/bb-11.0/sql/sql_parse.cc:6263

#27 0x0000555f4a5f4fac in mysql_execute_command (thd=0x7f8010000db8, is_called_from_prepared_stmt=false) at /data/src/bb-11.0/sql/sql_parse.cc:3947

#28 0x0000555f4a60226e in mysql_parse (thd=0x7f8010000db8, rawbuf=0x7f8010015490 "SELECT pk FROM t WHERE pk > 2 AND a IS NULL", length=43, parser_state=0x7f802256e3c0) at /data/src/bb-11.0/sql/sql_parse.cc:7998

#29 0x0000555f4a5ef251 in dispatch_command (command=COM_QUERY, thd=0x7f8010000db8, packet=0x7f801000ba19 "", packet_length=43, blocking=true) at /data/src/bb-11.0/sql/sql_parse.cc:1894

#30 0x0000555f4a5eddf8 in do_command (thd=0x7f8010000db8, blocking=true) at /data/src/bb-11.0/sql/sql_parse.cc:1407

#31 0x0000555f4a7aed69 in do_handle_one_connection (connect=0x555f4e54aa68, put_in_cache=true) at /data/src/bb-11.0/sql/sql_connect.cc:1416

#32 0x0000555f4a7aeaff in handle_one_connection (arg=0x555f4e53a528) at /data/src/bb-11.0/sql/sql_connect.cc:1318

#33 0x0000555f4ac6a00a in pfs_spawn_thread (arg=0x555f4e54a5d8) at /data/src/bb-11.0/storage/perfschema/pfs.cc:2201

#34 0x00007f80280a0ea7 in start_thread (arg=<optimized out>) at pthread_create.c:477

#35 0x00007f8027c8faef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95