Fix for the js-interop crash

tests/html/js_typed_interop_anonymous_unreachable_test.dart

Index: tests/html/js_typed_interop_anonymous_unreachable_test.dart
diff --git a/tests/html/js_typed_interop_anonymous_unreachable_test.dart b/tests/html/js_typed_interop_anonymous_unreachable_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9a5b44df0ad59dfd4a2e0c4c0e8a9ed8277efd18
--- /dev/null
+++ b/tests/html/js_typed_interop_anonymous_unreachable_test.dart
@@ -0,0 +1,30 @@
+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library js_typed_interop_anonymous_test;
+
+import 'dart:html';
+import 'dart:js' as js;
+
+import 'package:js/js.dart';
+import 'package:unittest/unittest.dart';
+import 'package:unittest/html_config.dart';
+
+@JS() @anonymous
+class Literal {
+  external factory Literal({int x, String y, num z});
+
+  external int get x;
+  external String get y;
+  external num get z;
+}
+
+main() {
+  useHtmlConfiguration();
+  test('nothing to do', () {
+    // This test is empty, but it is a regression for Issue# 24974: dartjs
+    // would crash trying to compile code that used @anonymous and that was
+    // not reachable from main.
+  });
+}