ructor() {
                super();
                this.i = this.attachInternals();
            }
        });
    </script>
</head>
<body>
    <form id="form-null">
        <test-form-element id="input-null" name="input-null"></test-form-element>
    </form>

    <form id="form-undefined">
        <test-form-element id="input-undefined" name="input-undefined"></test-form-element>
    </form>

    <script>
      test(() => {
        const input = document.getElementById("input-null");
        input.i.setFor