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