Online DDL fails while checking for instant alter condition

                Field** af = altered_table->field;

                Field** const end = altered_table->field

                        + altered_table->s->fields;

                for (unsigned c = 0; af < end; af++) {

                        if (!(*af)->stored_in_db()) {

                                continue;

                        }

                        const dict_col_t* col = dict_table_get_nth_col(

                                &ib_table, c++);

--source include/have_innodb.inc

create table t1(f1 char(10) not null) row_format=redundant, engine=innodb;

alter table t1 ADD COLUMN ( tscol5 DATETIME NOT NULL, tcol1 TIME NOT NULL DEFAULT 0, ecol6 SET('foo','bar') DEFAULT NULL ), ADD COLUMN IF NOT EXISTS ( scol8 VARBINARY(100) DEFAULT NULL ), change column f1 f1 char(10) default null, LOCK=SHARED;

drop table t1;

mariadbd: /home/thiru/mariarepo/10.6/10.6-test/storage/innobase/include/dict0dict.inl:370: dict_col_t* dict_table_get_nth_col(const dict_table_t*, ulint): Assertion `pos < table->n_def' failed.

include/dict0dict.inl:371(dict_table_get_nth_col(dict_table_t const*, unsigned long))[0x56543fbb129b]

handler/handler0alter.cc:1768(instant_alter_column_possible(dict_table_t const&, Alter_inplace_info const*, TABLE const*, TABLE const*, bool))[0x56543fbb5b9d]

handler/handler0alter.cc:2453(ha_innobase::check_if_supported_inplace_alter(TABLE*, Alter_inplace_info*))[0x56543fbb7c9e]

sql/sql_table.cc:10220(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, bool))[0x56543f4ea25e]

sql/sql_alter.cc:542(Sql_cmd_alter_table::execute(THD*))[0x56543f59d444]

sql/sql_parse.cc:5996(mysql_execute_command(THD*, bool))[0x56543f3e930f]

sql/sql_parse.cc:8029(mysql_parse(THD*, char*, unsigned int, Parser_state*))[0x56543f3ef3aa]