anchor.diff:    final Source librarySource;
   
     /**
  +   * The URI of [librarySource].
  +   */
  +  String libraryUri;
  +
  +  /**
      * Indicates whether [librarySource] is the `dart:core` library.
      */
     bool isCoreLibrary;
  
positive.code: 
    _LibraryResynthesizer(this.summaryResynthesizer, this.linkedLibrary,
        this.unlinkedUnits, this.librarySource) {
      isCoreLibrary = librarySource.uri.toString() == 'dart:core';
    }
  
    /**
  
negative.code:   List<String> getReferencedLocationComponents(
        int dependencyIndex, int unit, String name) {
      if (dependencyIndex == 0) {
        String referencedLibraryUri = libraryUri;
        String partUri;
        if (unit != 0) {
          String uri = unlinkedUnits[0].publicNamespace.parts[unit - 1];
  