Assertion failed: precision > 0 in decimal_bin_size upon SELECT with DISTINCT, CAST and other functions

CREATE TABLE t1 (b LONGBLOB);

INSERT IGNORE INTO t1 VALUES ('foo'),('bar');

SELECT DISTINCT - GREATEST( b, CAST( NULL AS DATETIME ) ) AS f FROM t1;

# Cleanup

DROP TABLE t1;

mysqld: /data/src/10.0/strings/decimal.c:1460: decimal_bin_size: Assertion `precision > 0' failed.

181003 12:12:48 [ERROR] mysqld got signal 6 ;

#7  0x00007fa7001ccee2 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6

#8  0x0000000000e689e8 in decimal_bin_size (precision=-1, scale=6) at /data/src/10.0/strings/decimal.c:1460

#9  0x00000000006c0e3e in my_decimal_get_binary_size (precision=4294967295, scale=6) at /data/src/10.0/sql/my_decimal.h:263

#10 0x00000000006b7b55 in calc_group_buffer (join=0x7fa6f88fad68, group=0x7fa6f88fbfa8) at /data/src/10.0/sql/sql_select.cc:22093

#11 0x0000000000685199 in JOIN::optimize_inner (this=0x7fa6f88fad68) at /data/src/10.0/sql/sql_select.cc:1755

#12 0x00000000006827fc in JOIN::optimize (this=0x7fa6f88fad68) at /data/src/10.0/sql/sql_select.cc:1041

#13 0x000000000068a7bd in mysql_select (thd=0x7fa6fa2a2070, rref_pointer_array=0x7fa6fa2a63a0, tables=0x7fa6f88fa6b0, wild_num=0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, proc_param=0x0, select_options=2147748609, result=0x7fa6f88fad48, unit=0x7fa6fa2a5a08, select_lex=0x7fa6fa2a60f8) at /data/src/10.0/sql/sql_select.cc:3334

#14 0x00000000006808c4 in handle_select (thd=0x7fa6fa2a2070, lex=0x7fa6fa2a5940, result=0x7fa6f88fad48, setup_tables_done_option=0) at /data/src/10.0/sql/sql_select.cc:377

#15 0x0000000000654db7 in execute_sqlcom_select (thd=0x7fa6fa2a2070, all_tables=0x7fa6f88fa6b0) at /data/src/10.0/sql/sql_parse.cc:5301

#16 0x000000000064d30d in mysql_execute_command (thd=0x7fa6fa2a2070) at /data/src/10.0/sql/sql_parse.cc:2557

#17 0x0000000000657c14 in mysql_parse (thd=0x7fa6fa2a2070, rawbuf=0x7fa6f88fa088 "SELECT DISTINCT - GREATEST( b, CAST( NULL AS DATETIME ) ) AS f FROM t1", length=70, parser_state=0x7fa70229c640) at /data/src/10.0/sql/sql_parse.cc:6637

#18 0x000000000064a534 in dispatch_command (command=COM_QUERY, thd=0x7fa6fa2a2070, packet=0x7fa6fb7e5071 "SELECT DISTINCT - GREATEST( b, CAST( NULL AS DATETIME ) ) AS f FROM t1", packet_length=70) at /data/src/10.0/sql/sql_parse.cc:1300

#19 0x0000000000649834 in do_command (thd=0x7fa6fa2a2070) at /data/src/10.0/sql/sql_parse.cc:1003

#20 0x000000000076af50 in do_handle_one_connection (thd_arg=0x7fa6fa2a2070) at /data/src/10.0/sql/sql_connect.cc:1377

#21 0x000000000076acc2 in handle_one_connection (arg=0x7fa6fa2a2070) at /data/src/10.0/sql/sql_connect.cc:1292

#22 0x0000000000acc98e in pfs_spawn_thread (arg=0x7fa6fa1a2370) at /data/src/10.0/storage/perfschema/pfs.cc:1861

#23 0x00007fa701ed0494 in start_thread (arg=0x7fa70229d700) at pthread_create.c:333

#24 0x00007fa70028993f in clone () from /lib/x86_64-linux-gnu/libc.so.6