Implement complex super assignment.

tests/language/super_setter_interceptor_test.dart

Index: tests/language/super_setter_interceptor_test.dart
===================================================================
--- tests/language/super_setter_interceptor_test.dart	(revision 0)
+++ tests/language/super_setter_interceptor_test.dart	(revision 0)
@@ -0,0 +1,36 @@
+// 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 that we correctly intercept super getter and setter calls.
+
+var expected;
+
+class A {
+  set length(a) { Expect.equals(expected, a); }
+  get length => 41;
+}
+
+class B extends A {
+  test() {
+    expected = 42;
+    Expect.equals(42, super.length = 42);
+    expected = 42;
+    Expect.equals(42, super.length += 1);
+    expected = 42;
+    Expect.equals(42, ++super.length);
+    expected = 40;
+    Expect.equals(40, --super.length);
+    expected = 42;
+    Expect.equals(41, super.length++);
+    expected = 40;
+    Expect.equals(41, super.length--);
+    Expect.equals(41, super.length);
+  }
+}
+
+main() {
+  // Ensures the list class is instantiated.
+  print([]);
+  new B().test();
+}