Support lazy JS types.

pkg/dev_compiler/test/codegen/lib/html/js_typed_interop_lazy_test.dart

+// 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.
+
+@JS()
+library js_typed_interop_lazy_test;
+
+import 'dart:html';
+
+import 'package:js/js.dart';
+import 'package:js/js_util.dart' as js_util;
+import 'package:expect/minitest.dart';
+
+@JS('someProperty')
+external get foo;
+
+@JS('baz.bar')
+external get bar;
+
+@JS('baz.LazyClass')
+class LazyClass {
+  external factory LazyClass(a);
+  external get a;
+}
+
+@anonymous
+@JS('some.bogus.ignored.js.path')
+class AnonClass {
+  external factory AnonClass({a});
+  external get a;
+}
+
+@anonymous
+@JS()
+class AnonClass2 {
+  external factory AnonClass2({b});
+  external get b;
+}
+
+abstract class Foo<T> {
+  T get obj;
+}
+
+// This class would cause compile time issues if JS classes are not properly lazy.
+class FooImpl extends Foo<LazyClass> {
+  LazyClass get obj => new LazyClass(100);
+}
+
+main() {
+  group('lazy property', () {
+    test('simple', () {
+      expect(foo, isNull);
+      js_util.setProperty(window, 'someProperty', 42);
+      expect(foo, equals(42));
+    });
+
+    test('nested', () {
+      js_util.setProperty(window, 'baz', js_util.newObject());
+      expect(bar, isNull);
+      js_util.setProperty(window, 'baz', js_util.jsify({'bar': 100}));
+      expect(bar, equals(100));
+    });
+  });
+
+  group('lazy class', () {
+    test('type literal', () {
+      // Fine because we can determine the class literals are equal without
+      // having to determine what (non-existant) JS type they correspond to.
+      var x = LazyClass;
+      var y = LazyClass;
+      expect(x == y, isTrue);
+    });
+
+    test('reference in type parameter', () {
+      var o = new FooImpl();
+      expect(o is Foo<LazyClass>, isTrue);
+    });
+
+    test('create instance', () {
+      document.body.append(new ScriptElement()
+        ..type = 'text/javascript'
+        ..innerHtml = r"""
+window.baz = {};
+
+baz.LazyClass = function LazyClass(a) {
+  this.a = a;
+};
+""");
+      var l = new LazyClass(42);
+      expect(l.a, equals(42));
+      expect(l is LazyClass, isTrue);
+      expect(l is AnonClass, isTrue);
+      expect((l as AnonClass) == l, isTrue);
+      expect((l as AnonClass2) == l, isTrue);
+      var anon = new AnonClass(a: 42);
+      expect(anon is! LazyClass, isTrue);
+      expect(anon is AnonClass, isTrue);
+      expect(anon is AnonClass2, isTrue);
+
+      // Sanity check that is and as are not broken.
+      expect(new Object() is! LazyClass, isTrue);
+      expect(new Object() is! AnonClass, isTrue);
+      expect(new Object() is! AnonClass2, isTrue);
+
+      expect(<AnonClass>[] is List<AnonClass>, isTrue);
+      // TODO(jacobr): why doesn't this test pass?
+      // expect(<AnonClass>[] is List<AnonClass2>, isTrue);
+      expect(<int>[] is! List<AnonClass>, isTrue);
+      expect(<AnonClass>[] is! List<LazyClass>, isTrue);
+      expect(<int>[] is! List<LazyClass>, isTrue);
+      expect(<LazyClass>[] is List<LazyClass>, isTrue);
+    });
+  });
+}