Support break and labeled statements.

frog/leg/resolver.dart

 // Copyright (c) 2012, 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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
 }
 
 class TreeElementMapping implements TreeElements {
@@ skipping 660 matching lines @@
 
   visitBlock(Block node) {
     visitIn(node.statements, new BlockScope(context));
   }
 
   visitDoWhile(DoWhile node) {
     visitLoopBodyIn(node, node.body, new BlockScope(context));
     visit(node.condition);
   }
 
+  visitEmptyStatement(EmptyStatement node) { }
+
   visitExpressionStatement(ExpressionStatement node) {
     visit(node.expression);
   }
 
   visitFor(For node) {
     Scope scope = new BlockScope(context);
     visitIn(node.initializer, scope);
     visitIn(node.condition, scope);
     visitIn(node.update, scope);
     visitLoopBodyIn(node, node.body, scope);
@@ skipping 734 matching lines @@
 class TopScope extends Scope {
   LibraryElement get library() => element;
 
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) => library.find(name);
 
   Element add(Element element) {
     throw "Cannot add an element in the top scope";
   }
 }