MigrateDestinationTerm::import() function update is wrong

Hi,

It's the first time I user Migrate module and I'm building a custom module based on BeerTerm example. I found the following code in file "term.inc", function import(), starting with line 127:

    // Updating previously-migrated content?
    if (isset($row->migrate_map_destid1)) {
      $term->tid = $row->migrate_map_destid1; // This line I think is not needed
      if (isset($term->tid)) {
        if ($term->tid != $row->migrate_map_destid1) { // This will never be true because of the previous marked line
          throw new MigrateException(t("Incoming tid !tid and map destination nid !destid1 don't match",
            array('!tid' => $term->tid, '!destid1' => $row->migrate_map_destid1)));
        }
      }
      else {
        $term->tid = $row->migrate_map_destid1;
      }
    }

Am I missing something or this is a error?