<p dir="auto">E.g.</p>
<div class="highlight highlight-source-rust notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="macro_rules! foo {
    ($func: ident) =&gt; { () } // warning: unused syntax variable `func`
}"><pre class="notranslate"><span class="pl-k">macro_rules!</span> foo <span class="pl-kos">{</span>
    <span class="pl-kos">(</span>$func<span class="pl-kos">:</span> ident<span class="pl-kos">)</span> =&gt; <span class="pl-kos">{</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-kos">}</span> <span class="pl-c">// warning: unused syntax variable `func`</span>
<span class="pl-kos">}</span></pre></div>