al types widen to their respective supertype. Specifically:</p>
<ul>
<li>Number literal types like <code>1</code> widen to <code>number</code>.</li>
<li>String literal types like <code>'hi'</code> widen to <code>string</code>.</li>
<li>Boolean literal types like <code>true</code> widen to <code>boolean</code>.</li>
<li>Enum members widen to their containing enum.</li>
</ul>
<p>An example of the last is:</p>
<p><pre class="typescript-code"><span class="tm-kw">enum</span> <span class="tm-typ"><span class="enu