subpartition name required but not used in template

In subpartition templates, subpartition name is required, but in interval partitioning, the subpartition names are not used, and system names are assigned.

SQL> @ interval.subpart.template.sql

Table dropped.

SQL> create table t
  2  (
  3  d date,
  4  s number,
  5  n number
  6  )
  7  partition by range ( d )
  8  interval ( numtoyminterval(1, 'month'))
  9  subpartition by list ( s )
 10  (
 11          partition p2018 values less than ( date '2019-01-01' )
 12          (
 13                  subpartition s01 values ( 1 )
 14          )
 15  );

Table created.

SQL>
SQL>
SQL> alter table t set subpartition template
  2  (
  3  subpartition values ( 1 )
  4  );
alter table t set subpartition template
*
ERROR at line 1:
ORA-14605: Name missing for subpartition / lob segment in template


SQL>
SQL> alter table t set subpartition template
  2  (
  3  subpartition s01 values ( 1 )
  4  );

Table altered.

SQL>
SQL> insert into t ( d, s, n ) values ( date '2019-01-01', 1, 0 );

1 row created.

SQL>
SQL> select partition_name, high_value
  2  from user_tab_partitions
  3  where table_name = 'T';

PARTITION_NAME                 HIGH_VALUE
------------------------------ ------------------------------------------------------------------------------------------
P2018                          TO_DATE(' 2019-01-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')
SYS_P379                       TO_DATE(' 2019-02-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')

SQL>
SQL> select subpartition_name, high_value
  2  from user_tab_subpartitions
  3  where table_name = 'T';

SUBPARTITION_NAME              HIGH_VALUE
------------------------------ ------------------------------------------------------------------------------------------
S01                            1
SYS_SUBP378                    1