anchor.diff:          AstFactory.functionDeclarationStatement(null, null, continueName,
               functionExpression([newName('x')], continueBlock)));
       breakTargets.add(identifier(breakName));
  -    breakLabels.add(breakName);
  +    breakLabels.add(null);
       continueTargets.add(identifier(continueName));
       visit(node.body)(f, r, () {
         addStatement(
  
positive.code: 
    ast.Block currentBlock;
    List<ast.Expression> breakTargets;
    List<ast.Expression> breakLabels;
  
    List<ast.Expression> continueTargets;
    List<ast.Expression> continueLabels;
  
    visit(ast.AstNode node) => node.accept(this);
  
  
negative.code: 
      var bodyBlock = currentBlock = emptyBlock();
      breakTargets.add(identifier(breakName));
      breakLabels.add(null);
      continueTargets.add(identifier(continueName));
      visit(node.body)(f, r, () {
        addStatement(
  