<!DOCTYPE html>
PASS if this does not crash
<script>
if (window.testRunner) {
testRunner.dumpAsText();
}
class X extends HTMLElement {
connectedCallback() {
}
};
Object.defineProperty(Array.prototype, 0, {
set: function(value) {
throw 'barf';
},
enumerable: true
});
customElements.define('x-x', X);
</script>