��使うこともできるでしょう:</p>
<pre><pre class="playground"><code class="language-rust"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">#[derive(Debug)]
</span><span class="boring">enum UsState {
</span><span class="boring">   Alabama,
</span><span class="boring">   Alaska,
</span><span class="boring">}
</span><span class="boring">
</span><span class="boring">enum Coin {
</span><span class="boring">   Penny,
</span><span class="boring">