<!DOCTYPE html>
<html>
<head>
<meta name="author" title="Ryosuke Niwa" href="mailto:rniwa@webkit.org">
<link rel="help" href="https://github.com/whatwg/html/issues/10854">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<script>

test(() => {
    class ABElement extends HTMLElement { };
    const scopedRegistry = new CustomElementRegistry;
    scopedRegistry.define('a-b', ABElement);
    assert_throws_js(TypeError, () => new ABElement)