<!DOCTYPE html>
<html>
<script>
  onload = () => {
    const shadowRoot = document.body.attachShadow({mode: 'open'});
    shadowRoot.append(document.createElement('slot'));
    shadowRoot.append(document.createElement('slot'));
    document.body.getBoundingClientRect();
    shadowRoot.replaceChildren();
    document.write("PASS if this doesn't crash");
    if (window.testRunner)
        testRunner.dumpAsText();
  };
</script>
<body></body>
</html>