anchor.diff:  class Outline {
     static Outline parse(Map m) {
       if (m == null) return null;
  -    return new Outline(Element.parse(m['element']), m['offset'], m['length'], children: m['children'] == null ? null : new List.from(m['children'].map((obj) => Outline.parse(obj))));
  +    return new Outline(Element.parse(m['element']), m['offset'], m['length'],
  +        children: m['children'] == null
  +            ? null
  +            : new List.from(m['children'].map((obj) => Outline.parse(obj))));
     }
   
     final Element element;
     final int offset;
     final int length;
  -  @optional final List<Outline> children;
  +  @optional
  +  final List<Outline> children;
   
     Outline(this.element, this.offset, this.length, {this.children});
   }
  
positive.code:     return _call('edit.getAssists', m).then(AssistsResult.parse);
    }
  
    Future<AvailableRefactoringsResult> getAvailableRefactorings(String file, int offset, int length) {
      Map m = {'file': file, 'offset': offset, 'length': length};
      return _call('edit.getAvailableRefactorings', m).then(AvailableRefactoringsResult.parse);
    }
  
    Future<FixesResult> getFixes(String file, int offset) {
  
negative.code: }
  
  class SortMembersResult {
    static SortMembersResult parse(Map m) =>
        new SortMembersResult(SourceFileEdit.parse(m['edit']));
  
    final SourceFileEdit edit;
  
  