anchor.diff:  //  @deprecated // unless we can find a way to encapsulate folder layout
   //  Future<T> load(Directory parentDirectory, {bool recursive: true});
   
  -  String toString() => 'Ref($name, $gitUri)';
   }
   
   abstract class ProjectGroupRef implements Ref<ProjectGroup> {
  
positive.code: //  @override
  //  Future<Project> load(Directory parentDirectory, {bool recursive: true}) =>
  //      Project.fromInstallDirectory(installDirectory(parentDirectory));
  }
  
negative.code: //  Future<ProjectGroup> load(Directory parentDirectory,
  //          {bool recursive: true}) =>
  //      ProjectGroup.fromInstallDirectory(parentDirectory);
  
    String toString() => 'ProjectGroupRef($name, $gitUri)';
  }
  
  class ProjectRefImpl extends _BaseRef implements ProjectRef {
  