Update enum encoding to latest spec.

tests/language/enum_test.dart

+// Copyright (c) 2014, 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.
+
+// SharedOptions=--enable-enum
+
+import 'package:expect/expect.dart';
+
+enum Enum1 { _ }
+enum Enum2 { A }
+enum Enum3 { B, C }
+enum Enum4 { D, E, }
+enum Enum5 { F, G, H }
+
+main() {
+  Expect.equals('Enum1._', Enum1._.toString());
+  Expect.equals(0, Enum1._.index);
+  Expect.listEquals([Enum1._], Enum1.values);
+  Enum1.values.forEach(test1);
+
+  Expect.equals('Enum2.A', Enum2.A.toString());
+  Expect.equals(0, Enum2.A.index);
+  Expect.listEquals([Enum2.A], Enum2.values);
+  Enum2.values.forEach(test2);
+
+  Expect.equals('Enum3.B', Enum3.B.toString());
+  Expect.equals('Enum3.C', Enum3.C.toString());
+  Expect.equals(0, Enum3.B.index);
+  Expect.equals(1, Enum3.C.index);
+  Expect.listEquals([Enum3.B, Enum3.C], Enum3.values);
+  Enum3.values.forEach(test3);
+
+  Expect.equals('Enum4.D', Enum4.D.toString());
+  Expect.equals('Enum4.E', Enum4.E.toString());
+  Expect.equals(0, Enum4.D.index);
+  Expect.equals(1, Enum4.E.index);
+  Expect.listEquals([Enum4.D, Enum4.E], Enum4.values);
+  Enum4.values.forEach(test4);
+
+  Expect.equals('Enum5.F', Enum5.F.toString());
+  Expect.equals('Enum5.G', Enum5.G.toString());
+  Expect.equals('Enum5.H', Enum5.H.toString());
+  Expect.equals(0, Enum5.F.index);
+  Expect.equals(1, Enum5.G.index);
+  Expect.equals(2, Enum5.H.index);
+  Expect.listEquals([Enum5.F, Enum5.G, Enum5.H], Enum5.values);
+  Enum5.values.forEach(test5);
+}
+
+test1(Enum1 e) {
+  int index;
+  switch (e) {
+    case Enum1._:
+      index = 0;
+      break;
+  }
+  Expect.equals(e.index, index);
+}
+
+test2(Enum2 e) {
+  int index;
+  switch (e) {
+    case Enum2.A:
+      index = 0;
+      break;
+  }
+  Expect.equals(e.index, index);
+}
+
+test3(Enum3 e) {
+  int index;
+  switch (e) {
+    case Enum3.C:
+      index = 1;
+      break;
+    case Enum3.B:
+      index = 0;
+      break;
+  }
+  Expect.equals(e.index, index);
+}
+
+test4(Enum4 e) {
+  int index;
+  switch (e) {
+    case Enum4.D:
+      index = 0;
+      break;
+    case Enum4.E:
+      index = 1;
+      break;
+  }
+  Expect.equals(e.index, index);
+}
+
+test5(Enum5 e) {
+  int index;
+  switch (e) {
+    case Enum5.H:
+      index = 2;
+      break;
+    case Enum5.F:
+      index = 0;
+      break;
+    case Enum5.G:
+      index = 1;
+      break;
+  }
+  Expect.equals(e.index, index);
+}