ot;{:?}&quot;</span>, <span class='ident'>list</span>);
}</pre>

<p>This will print <code>Cons(1, Cons(2, Nil))</code>.</p>

<p>Recursive structures must be boxed, because if the definition of <code>Cons</code>
looked like this:</p>
<pre class='rust rust-example-rendered'>
<span class='ident'>Cons</span>(<span class='ident'>T</span>, <span class='ident'>List</span><span class='op'>&lt;</span><span class='ident'>T</span><span class='op'>&gt;</span>),</pre>

<p>It wouldn&#39;t work. This is because the size o