anchor.diff:    }
   
     /// Return the [_File] for the given [relative] URI, maybe `null`.
  -  _File? _fileForRelativeUri(DeclarationsContext context, Uri relative) {
  +  _File? _fileForRelativeUri(
  +    DeclarationsContext context,
  +    List<String> partOrUriList,
  +    Uri relative,
  +  ) {
       var absoluteUri = resolveRelativeUri(uri, relative);
  -    return tracker._getFileByUri(context, absoluteUri);
  +    return tracker._getFileByUri(context, partOrUriList, absoluteUri);
     }
   
     void _putFileDeclarationsToByteStore(String contentKey) {
  
positive.code:     _pathToFile[path] = file;
      _uriToFile[uri] = file;
  
      file.refresh(context);
      return file;
    }
  
  
negative.code: 
      // Resolve exports and parts.
      for (var export in exports) {
        export.file = _fileForRelativeUri(context, partOrUriList, export.uri);
      }
      for (var part in parts) {
        part.file = _fileForRelativeUri(context, partOrUriList, part.uri);
      }
      exports.removeWhere((e) => e.file == null);
      parts.removeWhere((e) => e.file == null);
  