DEFINE_TRACE(HTMLFormElement) {
  visitor->trace(m_pastNamesMap);
  visitor->trace(m_radioButtonGroupScope);
  visitor->trace(m_associatedElements);
  visitor->trace(m_imageElements);
  visitor->trace(m_plannedNavigation);
  HTMLElement::trace(visitor);
}

Historically, this outdated classification described vulnerabilities from improper handling of data inputs, leading to unexpected program behavior or errors when input validation fails.