Check enums in switch cases.

pkg/compiler/lib/src/elements/modelx.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.
 
 library elements.modelx;
 
 import 'elements.dart';
 import '../constants/expressions.dart';
 import '../helpers/helpers.dart';  // Included for debug helpers.
 import '../tree/tree.dart';
@@ skipping 2396 matching lines @@
     if (origin != null) {
       return 'patch ${super.toString()}';
     } else if (patch != null) {
       return 'origin ${super.toString()}';
     } else {
       return super.toString();
     }
   }
 }
 
-class EnumClassElementX extends ClassElementX {
+class EnumClassElementX extends ClassElementX implements EnumClassElement {
   final Enum node;
+  Iterable<FieldElement> enumValuesCache;
 
   EnumClassElementX(String name, Element enclosing, int id, this.node)
       : super(name, enclosing, id, STATE_NOT_STARTED);
 
   @override
   bool get hasNode => true;
 
   @override
   Token get position => node.name.token;
 
   @override
   bool get isEnumClass => true;
 
   @override
   Node parseNode(Compiler compiler) => node;
 
   @override
-  accept(ElementVisitor visitor) => visitor.visitClassElement(this);
+  accept(ElementVisitor visitor) => visitor.visitEnumClassElement(this);
 
   List<DartType> computeTypeParameters(Compiler compiler) => const <DartType>[];
+
+  Iterable<FieldElement> get enumValues {
+    assert(invariant(this, enumValuesCache != null,
+        message: "enumValues has not been computed for $this."));
+    return enumValuesCache;
+  }
+
+  void set enumValues(Iterable<FieldElement> values) {
+    assert(invariant(this, enumValuesCache == null,
+        message: "enumValues has already been computed for $this."));
+    enumValuesCache = values;
+  }
 }
 
 class EnumConstructorElementX extends ConstructorElementX {
   final FunctionExpression node;
 
   EnumConstructorElementX(EnumClassElementX enumClass,
                           Modifiers modifiers,
                           this.node)
       : super('', // Name.
               ElementKind.GENERATIVE_CONSTRUCTOR,
@@ skipping 347 matching lines @@
   AstElement get definingElement;
 
   bool get hasResolvedAst => definingElement.hasTreeElements;
 
   ResolvedAst get resolvedAst {
     return new ResolvedAst(declaration,
         definingElement.node, definingElement.treeElements);
   }
 
 }