>

<p>There are two kinds of reference:</p>

<ul>
<li>Shared reference: <code>&amp;</code></li>
<li>Mutable reference: <code>&amp;mut</code></li>
</ul>

<p>Which obey the following rules:</p>

<ul>
<li>A reference cannot outlive its referent</li>
<li>A mutable reference cannot be aliased</li>
</ul>

<p>That&#39;s it. That&#39;s the whole model. Of course, we should probably define
what <em>aliased</em> means. To define aliasing, we must define the notion of
<em>paths</em> and <em>liveness</em>.</p>

<p><str