lass="tm-typ">any</span> }
<span class="tm-kw">function</span> <span class="tm-mth">f</span>(<span class="tm-vr">x</span>: <span class="error" tabindex="0" aria-describedby="errLabel-2304-43-1"><span class="error-highlight"></span><span class="tm-typ">C</span><span id="errLabel-2304-43-1" role="tooltip" class="error-tooltip">Cannot find name 'C'.</span></span>) {
  <span class="tm-kw">if</span> (<span class="tm-vr">x</span> <span class="tm-kw">instanceof</span> <span class="className">D</span>) {
    <span 