ASAN memcpy-param-overlap in fill_alter_inplace_info

create table t5 (pk int not null primary key, a char(20), unique key (pk), key (a(10)));

alter table t5  drop primary key ;

==19031==ERROR: AddressSanitizer: memcpy-param-overlap: memory ranges [0x62b00007fc18,0x62b00007fc28) and [0x62b00007fc20, 0x62b00007fc30) overlap

    #0 0x7f561679d662 in __asan_memcpy (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x8c662)

    #1 0xbcc01f in fill_alter_inplace_info /10.4/sql/sql_table.cc:7080

    #2 0xbdd073 in mysql_alter_table(THD*, st_mysql_const_lex_string const*, st_mysql_const_lex_string const*, HA_CREATE_INFO*, TABLE_LIST*, Alter_info*, unsigned int, st_order*, bool) /10.4/sql/sql_table.cc:9931

    #3 0xd343c6 in Sql_cmd_alter_table::execute(THD*) /10.4/sql/sql_alter.cc:508

    #4 0x9b9d78 in mysql_execute_command(THD*) /10.4/sql/sql_parse.cc:6098

    #5 0x9c451f in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) /10.4/sql/sql_parse.cc:7908

    #6 0x99e359 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) /10.4/sql/sql_parse.cc:1843

    #7 0x99b197 in do_command(THD*) /10.4/sql/sql_parse.cc:1360

    #8 0xd1edb4 in do_handle_one_connection(CONNECT*) /10.4/sql/sql_connect.cc:1404

    #9 0xd1e75a in handle_one_connection /10.4/sql/sql_connect.cc:1306

    #10 0x20f3ae2 in pfs_spawn_thread /10.4/storage/perfschema/pfs.cc:1862

    #11 0x7f56151c96b9 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x76b9)

    #12 0x7f561445a41c in clone (/lib/x86_64-linux-gnu/libc.so.6+0x10741c)