Handle @proxy classes in type checker.

tests/language/proxy2_test.dart

+// Copyright (c) 2013, 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.
+
+// Test for static warnings for member access on classes with @proxy annotation.
+
+import 'dart:core' as core;
+
+class Fake {
+  const Fake();
+}
+
+const proxy = const Fake();
+
+@proxy
+class WrongProxy {}
+
+@core.proxy
+class PrefixProxy {}
+
+main() {
+  try { new WrongProxy().foo; } catch (e) {}  /// 01: static type warning
+  try { new WrongProxy().foo(); } catch (e) {}  /// 02: static type warning
+
+  try { new PrefixProxy().foo; } catch (e) {} /// 03: ok
+  try { new PrefixProxy().foo(); } catch (e) {} /// 04: ok
+}