anchor.diff:  
     void _buildOutlines() {
       _resolveUriDirectives();
  -    _addExporters();
       _computeLibraryScopes();
       _addSyntheticConstructors();
       _createTypeSystem();
  
positive.code:   }
  
    void _computeLibraryScopes() {
      var exporters = new Set<SourceLibraryBuilder>();
      var exportees = new Set<SourceLibraryBuilder>();
  
      for (var library in builders.values) {
        library.addLocalDeclarations();
        if (library.exporters.isNotEmpty) {
          exportees.add(library);
          for (var exporter in library.exporters) {
            exporters.add(exporter.exporter);
          }
        }
      }
  
      for (var library in builders.values) {
        library.buildInitialExportScope();
      }
  
      var both = new Set<SourceLibraryBuilder>();
  
negative.code:     _createLinkingBundle();
    }
  
    void _addSyntheticConstructors() {
      for (var library in builders.values) {
        library.addSyntheticConstructors();
  