Assertion `0' failed in Explain_table_access::tag_to_json(Json_writer*, explain_extra_tag)

CREATE TABLE t1 (a INT, KEY(a));

INSERT INTO t1 VALUES (1),(2);

CREATE TABLE t2 (b INT);

INSERT INTO t2 VALUES (3),(4);

EXPLAIN FORMAT=JSON SELECT * FROM t1 AS outer_t1 WHERE a <> ALL ( SELECT a FROM t1, t2 WHERE b <> outer_t1.a );

sql/sql_explain.cc:1133: void Explain_table_access::tag_to_json(Json_writer*, explain_extra_tag): Assertion `0' failed.

141204 18:44:59 [ERROR] mysqld got signal 6 ;

#6  0x00007fafa29b36f1 in *__GI___assert_fail (assertion=0x7fafa5c49cf0 "0", file=<optimized out>, line=1133, function=0x7fafa5c4b000 "void Explain_table_access::tag_to_json(Json_writer*, explain_extra_tag)") at assert.c:81

#7  0x00007fafa5435e58 in Explain_table_access::tag_to_json (this=0x7faf99456a38, writer=0x7fafa4d96020, tag=ET_FULL_SCAN_ON_NULL_KEY) at 10.1/sql/sql_explain.cc:1133

#8  0x00007fafa54365ac in Explain_table_access::print_explain_json (this=0x7faf99456a38, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:1254

#9  0x00007fafa5434b2e in Explain_basic_join::print_explain_json (this=0x7faf994569c0, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:739

#10 0x00007fafa5434a3a in Explain_select::print_explain_json (this=0x7faf994569c0, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:720

#11 0x00007fafa54343b1 in Explain_node::print_explain_json_for_children (this=0x7faf99458360, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:590

#12 0x00007fafa5434b8b in Explain_basic_join::print_explain_json (this=0x7faf99458360, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:744

#13 0x00007fafa5434a3a in Explain_select::print_explain_json (this=0x7faf99458360, query=0x7faf99456950, writer=0x7fafa4d96020, is_analyze=false) at 10.1/sql/sql_explain.cc:720

#14 0x00007fafa5432fb0 in Explain_query::print_explain_json (this=0x7faf99456950, output=0x7faf99584038, is_analyze=false) at 10.1/sql/sql_explain.cc:205

#15 0x00007fafa52dad57 in execute_sqlcom_select (thd=0x7faf9d726070, all_tables=0x7faf99582340) at 10.1/sql/sql_parse.cc:5706

#16 0x00007fafa52d16c3 in mysql_execute_command (thd=0x7faf9d726070) at 10.1/sql/sql_parse.cc:2892

#17 0x00007fafa52de1d7 in mysql_parse (thd=0x7faf9d726070, rawbuf=0x7faf99582088 "EXPLAIN FORMAT=JSON SELECT * FROM t1 AS outer_t1 WHERE a <> ALL ( SELECT a FROM t1, t2 WHERE b <> outer_t1.a )", length=110, parser_state=0x7fafa4d971c0) at 10.1/sql/sql_parse.cc:7028

#18 0x00007fafa52cdade in dispatch_command (command=COM_QUERY, thd=0x7faf9d726070, packet=0x7faf9dbfa071 "", packet_length=110) at 10.1/sql/sql_parse.cc:1460

#19 0x00007fafa52cc8fc in do_command (thd=0x7faf9d726070) at 10.1/sql/sql_parse.cc:1089

#20 0x00007fafa53fb538 in do_handle_one_connection (thd_arg=0x7faf9d726070) at 10.1/sql/sql_connect.cc:1347

#21 0x00007fafa53fb27d in handle_one_connection (arg=0x7faf9d726070) at 10.1/sql/sql_connect.cc:1258

#22 0x00007fafa5997fee in pfs_spawn_thread (arg=0x7fafa20249f0) at 10.1/storage/perfschema/pfs.cc:1860

#23 0x00007fafa49cdb50 in start_thread (arg=<optimized out>) at pthread_create.c:304

#24 0x00007fafa2a6420d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112