anchor.diff:    }
   
     /**
  +   * Return the [_ExportNamespace] for the library with the given [absoluteUri].
  +   * The export namespace might be full (will all exports included), or
  +   * partial (with public namespace, and only some of the exports included).
  +   */
  +  _ExportNamespace getExportNamespace(String absoluteUri) {
  +    _ExportNamespace exportNamespace = exportNamespaces[absoluteUri];
  +    if (exportNamespace == null) {
  +      _Namespace publicNamespace = aggregatePublicNamespace(absoluteUri);
  +      exportNamespace = new _ExportNamespace(publicNamespace);
  +      exportNamespaces[absoluteUri] = exportNamespace;
  +    }
  +    return exportNamespace;
  +  }
  +
  +  /**
      * Wrapper around [getImport] that caches the return value in [importCache].
      */
     UnlinkedPublicNamespace getImportCached(String absoluteUri) {
  
positive.code: }
  
  /**
   * A [_Meaning] stores all the information necessary to find the declaration
   * referred to by a name in a namespace.
   */
  
negative.code:    * List of public namespaces corresponding to each entry in [dependencies].
     */
    final List<_Namespace> dependencyToPublicNamespace = <_Namespace>[];
  
    /**
     * Map from absolute URI of a library to its export namespace.
     */
    final Map<String, _ExportNamespace> exportNamespaces = {};
  
    _Prelinker(this.definingUnitUri, this.definingUnit, this.getPart,
        this.getImport, this.getDeclaredVariable) {
  