anchor.diff:    /// Indicates whether any problems have been reported yet.
     bool problemsReported = false;
   
  +  /// Package dependencies that were actually discovered
  +  final actualPackageDependencies = <String>[];
  +
     /// Check for problems resulting from URI [src] having a direct dependency on
     /// URI [dst].
     void checkDependency(Uri src, Uri dst) {
  
positive.code: main() async {
    exit(await new _SubpackageRelationshipsTest().run());
  }
  
  /// Map from subpackage name to the rules for what the subpackage is allowed to
  /// depend directly on.
  
negative.code:         for (var dependency in library.dependencies) {
            checkDependency(library.uri, dependency.uri);
          }
        }
      }
      for (var package in allowedPackageDependencies) {
        if (!actualPackageDependencies.contains(package)) {
          problem('$package is listed in allowedPackageDependencies, '
              'but is not used');
        }
      }
      subpackageRules.forEach((subpackage, rule) {
  