yword">val</span>&nbsp;runtime_warnings_enabled&nbsp;:&nbsp;unit&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;bool<br>
&nbsp;&nbsp;<span class="keyword">external</span>&nbsp;opaque_identity&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>a&nbsp;=&nbsp;<span class="string">"%opaque"</span><br>
<span class="keyword">end</span></code>
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