div class="info ">
<div class="info-desc">
<p>Return whether runtime warnings are currently enabled.</p>
</div>
<ul class="info-attributes">
<li><b>Since</b> 4.03.0</li>
</ul>
</div>
<h2 id="1_Optimization">Optimization</h2>
<pre><span id="VALopaque_identity"><span class="keyword">val</span> opaque_identity</span> : <code class="type">'a -&gt; 'a</code></pre><div class="info ">
<div class="info-desc">
<p>For the purposes of optimization, <code class="code">opaque_identity</code> behaves like an
    unknown 