Server crashes in is_invalid_role_name on reloading ACL with a blank role name

create role ' ';

flush privileges;

#3  <signal handler called>

#4  0x00000000005f4396 in is_invalid_role_name (str=0x0) at 10.0/sql/sql_acl.cc:804

#5  0x00000000005f51af in acl_load (thd=0x7f070efd4070, tables=0x7f0715caed30) at 10.0/sql/sql_acl.cc:1167

#6  0x00000000005f6c2a in acl_reload (thd=0x7f070efd4070) at 10.0/sql/sql_acl.cc:1614

#7  0x00000000007cb2b8 in reload_acl_and_cache (thd=0x7f070efd4070, options=1, tables=0x0, write_to_binlog=0x7f0715cb11dc) at 10.0/sql/sql_reload.cc:82

#8  0x0000000000682efb in mysql_execute_command (thd=0x7f070efd4070) at 10.0/sql/sql_parse.cc:4278

#9  0x0000000000688a5e in mysql_parse (thd=0x7f070efd4070, rawbuf=0x7f070dbf8088 "flush privileges", length=16, parser_state=0x7f0715cb1600) at 10.0/sql/sql_parse.cc:6531

#10 0x000000000067b43f in dispatch_command (command=COM_QUERY, thd=0x7f070efd4070, packet=0x7f070efca071 "flush privileges", packet_length=16) at 10.0/sql/sql_parse.cc:1308

#11 0x000000000067a725 in do_command (thd=0x7f070efd4070) at 10.0/sql/sql_parse.cc:999

#12 0x0000000000798c86 in do_handle_one_connection (thd_arg=0x7f070efd4070) at 10.0/sql/sql_connect.cc:1378

#13 0x00000000007989e5 in handle_one_connection (arg=0x7f070efd4070) at 10.0/sql/sql_connect.cc:1293

#14 0x0000000000cdb22b in pfs_spawn_thread (arg=0x7f070d9da5f0) at 10.0/storage/perfschema/pfs.cc:1860

#15 0x00007f0715934b50 in start_thread (arg=<optimized out>) at pthread_create.c:304

#16 0x00007f0713bea95d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112