ck <a href="https://macropy3.readthedocs.io/en/latest/tco.html#trampolining">like this</a>. But I was wrong.</p>
<p>It does ensure the proper declaration is used on implementations which support a proper TCO and signals warning or error on others.</p>
<p>Here is an example on SBCL, which supports TCO only if <code>speed</code> declared to be greater or equal to <code>debug</code>:</p>
<pre><code class='lisp'>POFTHEDAY&gt; (declaim (optimize (debug 3) (speed 1))

POFTHEDAY&gt; (labels ((sum-aux (acc x)
     