anchor.diff:      buffer.add(other.toString());
     }
   
  +  CodeBuffer addAll(Collection<Object> objects) {
  +    for (Object obj in objects) {
  +      add(obj);
  +    }
  +    return this;
  +  }
  +
     CodeBuffer addCharCode(int charCode) {
       return add(new String.fromCharCodes([charCode]));
     }
  
positive.code:       : buffer = new StringBuffer(),
          sourceLocations = new List<SourceLocation>();
  
    int get length() {
      return buffer.length;
    }
  
    bool isEmpty() {
      return buffer.isEmpty();
  
negative.code: }
  
  class SourceLocation {
    final Element element;
    final Token token;
    final int offsetDelta;
    SourceLocation(this.element, this.token, this.offsetDelta);
  }
  