Assertion `fixed == 1' failed in Item_singlerow_subselect::val_int()

--source include/have_partition.inc

CREATE TABLE t1 (v1 int);

ALTER TABLE t1 PARTITION BY system_time INTERVAL (SELECT 4 FROM dual) HOUR 

   (PARTITION ver_p1 HISTORY, PARTITION ver_pn CURRENT) ;

/10.3/sql/item_subselect.cc:1317: virtual longlong Item_singlerow_subselect::val_int(): Assertion `fixed == 1' failed.

190218 14:50:08 [ERROR] mysqld got signal 6 ;

stdlib/abort.c:91(__GI_abort)[0x7fe54786302a]

assert/assert.c:92(__assert_fail_base)[0x7fe547859bd7]

/lib/x86_64-linux-gnu/libc.so.6(+0x2dc82)[0x7fe547859c82]

sql/item_subselect.cc:1318(Item_singlerow_subselect::val_int())[0x562b506728ba]

sql/item_timefunc.cc:1338(get_interval_value(Item*, interval_type, INTERVAL*))[0x562b506e1369]

sql/partition_info.h:404(partition_info::vers_set_interval(Item*, interval_type, long))[0x562b50332c62]

sql/sql_yacc.yy:6066(MYSQLparse(THD*))[0x562b502c74b6]

sql/sql_parse.cc:10106(parse_sql(THD*, Parser_state*, Object_creation_ctx*, bool))[0x562b4fdd1bb2]

sql/sql_parse.cc:8048(mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool))[0x562b4fdc571b]

sql/sql_parse.cc:1856(dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool))[0x562b4fda064a]

sql/sql_parse.cc:1396(do_command(THD*))[0x562b4fd9d76c]

sql/sql_connect.cc:1403(do_handle_one_connection(CONNECT*))[0x562b500f0fe8]

sql/sql_connect.cc:1310(handle_one_connection)[0x562b500f09c5]

perfschema/pfs.cc:1864(pfs_spawn_thread)[0x562b5141b0b1]

/lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba)[0x7fe54849e6ba]

x86_64/clone.S:111(clone)[0x7fe54793341d]

190218 15:02:52 [ERROR] mysqld got signal 11 ;

Server version: 10.3.12-MariaDB

sql/item_cmpfunc.h:3264(THD::is_error() const)[0x561ddee2d621]

sql/item_subselect.cc:1320(Item_singlerow_subselect::val_int())[0x561ddee2dafe]

sql/item_timefunc.cc:1339(get_interval_value(Item*, interval_type, INTERVAL*))[0x561ddee4af5f]

sql/partition_info.h:407(partition_info::vers_set_interval(Item*, interval_type, long))[0x561dded50ba5]

sql/sql_yacc.yy:6066(MYSQLparse(THD*))[0x561dded2d775]

sql/sql_parse.cc:10103(parse_sql(THD*, Parser_state*, Object_creation_ctx*, bool))[0x561ddebe6205]

sql/sql_parse.cc:8047(mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool))[0x561ddebe64a6]

sql/sql_parse.cc:1851(dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool))[0x561ddebe86f5]

sql/sql_parse.cc:1398(do_command(THD*))[0x561ddebe8e9e]

sql/sql_connect.cc:1402(do_handle_one_connection(CONNECT*))[0x561ddecb081f]

sql/sql_connect.cc:1310(handle_one_connection)[0x561ddecb0944]

/lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba)[0x7fdaac1bd6ba]

x86_64/clone.S:111(clone)[0x7fdaab02241d]

Query (0x7fda440115c0): ALTER TABLE t1 PARTITION BY system_time INTERVAL (SELECT 4 FROM dual) HOUR     (PARTITION ver_p1 HISTORY, PARTITION ver_pn CURRENT)