de>syn</code> and <code>proc_macro2</code>. <strong>This form gives the best looking error messages and
should be used whenever possible!</strong></li>
</ul>
<p>The second argument is the error message, it must implement [<code>ToString</code>].</p>
</li>
<li>
<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><div class="example-wrap"><pre class="rust rust-example-rendered ignore">
<span class="macro">abort</span><span class="macro