anchor.diff:    InitializationCrawler(this.typeFilter, this.customFilter, {Uri from})
         : _rootLibrary = from == null
             ? _root
  -          : currentMirrorSystem().libraries[from] {
  +          : _libs[from] {
       if (_rootLibrary == null) throw 'Unable to find library at $from.';
     }
   
  
positive.code:         if (declaration.superclass.owner == declaration.owner) {
            _readAnnotations(declaration.superclass, queue);
          } else {
            var superMetas = declaration.superclass.metadata
                .where((m) => _filterMetadata(declaration.superclass, m))
                .toList();
            if (superMetas.isNotEmpty) {
              throw new UnsupportedError(
                  'We have detected a cycle in your import graph when running '
                  'initializers on ${declaration.qualifiedName}. This means the '
                  'super class ${declaration.superclass.qualifiedName} has a '
                  'dependency on this library (possibly transitive).');
            }
          }
  
negative.code:       return false;
      }
      if (customFilter != null && !customFilter(meta.reflectee)) return false;
      if (!_annotationsFound.containsKey(declaration)) return true;
      if (_annotationsFound[declaration].contains(meta)) return false;
      return true;
    }
  