code: public boolean canTraverseOutsideSubtree()
    {
  
      if (super.canTraverseOutsideSubtree())
        return true;
      else
      {
        int n = m_args.length;
  
        for (int i = 0; i < n; i++)
        {
          if (m_args[i].canTraverseOutsideSubtree())
            return true;
        }
  
        return false;
      }
    }
docs: Tell if this expression or it's subexpressions can traverse outside
  the current subtree.
  
  @return true if traversal outside the context node's subtree can occur.