anchor.diff:        var library = _sdkLibraries.singleWhere(foundLibraryName);
         // Look to see if it's a fully qualified library name.
         var scope = determineLookupFunc(remainingName)(library, remainingName);
  -      if (scope != null) return docName(scope);
  +      if (scope != null) return packagePrefix + docName(scope);
       }
     }
     return null;
  
positive.code:       _methods(library.functions),
        _variables(library.variables),
        _isHidden(library));
    _findPackage(result, library);
    logger.fine('Generated library for ${result.name}');
    return result;
  }
  
negative.code:     });
  }
  
  /// For a library's [mirror], determine the name of the package (if any) we
  /// believe it came from (because of its file URI).
  ///
  /// If [library] is specified, we set the packageName field. If no package could
  /// be determined, we return an empty string.
  String _findPackage(LibraryMirror mirror, [Library library]) {
    if (mirror.uri.scheme != 'file') return '';
    var filePath = mirror.uri.toFilePath();
    // We assume that we are documenting only libraries under package/lib
    var rootdir = path.dirname((path.dirname(filePath)));
    var pubspec = path.join(rootdir, 'pubspec.yaml');
    var packageName = _packageName(pubspec);
    if (library != null) {
      library.packageName = packageName;
      // If we are the main library in a package, associate the package readme
      // with us.
      // TODO(alanknight): We can't really rely on all packages having a library
  