anchor.diff:    final ContextCache contextCache;
   
     SummaryDataStore summaryDataStore;
  -  AnalysisOptions analysisOptions;
  +  AnalysisOptionsImpl analysisOptions;
     Map<Uri, File> uriToFileMap;
     final List<Source> explicitSources = <Source>[];
     final List<PackageBundle> unlinkedBundles = <PackageBundle>[];
   
  +  SourceFactory sourceFactory;
  +  DeclaredVariables declaredVariables;
     AnalysisDriver analysisDriver;
   
     PackageBundleAssembler assembler;
     final Map<String, UnlinkedUnit> uriToUnit = <String, UnlinkedUnit>{};
  +
  +  final bool buildSummary2 = true;
  +  final Map<String, ParsedUnitResult> inputParsedUnitResults = {};
  +  summary2.LinkedElementFactory elementFactory;
   
     // May be null.
     final DependencyTracker dependencyTracker;
  
positive.code: 
  import 'package:analyzer/dart/analysis/declared_variables.dart';
  import 'package:analyzer/dart/analysis/results.dart';
  import 'package:analyzer/error/error.dart';
  import 'package:analyzer/file_system/file_system.dart';
  import 'package:analyzer/src/dart/analysis/byte_store.dart';
  
negative.code:         new FileContentOverlay(),
          null,
          sourceFactory,
          analysisOptions,
          externalSummaries: summaryDataStore);
  
      declaredVariables = new DeclaredVariables.fromMap(options.definedVariables);
      analysisDriver.declaredVariables = declaredVariables;
  
      if (buildSummary2) {
        _createLinkedElementFactory();
      }
  
      scheduler.start();
    }
  
    void _createLinkedElementFactory() {
      var rootReference = summary2.Reference.root();
      var dartCoreRef = rootReference.getChild('dart:core');
      dartCoreRef.getChild('dynamic').element = DynamicElementImpl.instance;
      dartCoreRef.getChild('Never').element = NeverElementImpl.instance;
  
      var analysisContext = RestrictedAnalysisContext(
        SynchronousSession(analysisOptions, declaredVariables),
        sourceFactory,
      );
  
      elementFactory = summary2.LinkedElementFactory(
        analysisContext,
        null,
        rootReference,
      );
  
      for (var bundle in summaryDataStore.bundles) {
        elementFactory.addBundle(
          summary2.LinkedBundleContext(elementFactory, bundle.bundle2),
        );
      }
    }
  
    /**
  