Solving ORA-22905: cannot access rows from a non-nested table item

Some time ago i wrote about Binding list variable. In fact it is conversion of string to rows. My example works fine in SQL but when used in PL/SQL it might cause error ORA-22905: cannot access rows from a non-nested table item. I do know what are the necessary conditions for this error, as it does not always happen in PL/SQL. I faced it usually for quite complicated queries. To overcome this problem I just cast binding variable to varchar2 as shown below:

  procedure test_proc(p_list in varchar2)
  is
  begin
    for r in (select items.extract('/l/text()').getStringVal() item
              from table(xmlSequence(
                extract(XMLType(''||
                  replace(cast (p_list as varchar2(4000)),
                          ',','')||'')
                      ,'/all/l'))) items) loop
      null;
    end loop;
  end;

It worked for me in all situations where I faced ORA-22905 on Oracle 10gR2 (10.2.0.3)

Paweł