title: About the function NCONC in Common Lisp
body: <p>I got a real stack overflow by typing the following codes</p>
  
  <pre><code>(setf l1 (list 1))
  
  (setf l2 (list 2))
  
  (nconc l1 l2)
  
  (nconc l2 l1)
  </code></pre>
  
  <p>Oops...</p>
  
  <p>Is that a bug?</p>