anchor.diff:        rootReference,
       );
       elementFactory.addBundle(
  -      LinkedBundleContext(elementFactory, dartCoreResult.bundle),
  +      LinkedBundleContext(elementFactory, sdkBundle),
       );
       elementFactory.addBundle(
         LinkedBundleContext(elementFactory, linkResult.bundle),
  
positive.code:   @failingTest
    test_unresolved_import() async {
      await super.test_unresolved_import();
    }
  
    LinkResult _link(Map<Source, String> codeMap) {
      // TODO(scheglov) support for parts
      var libraryUnitMap = <Source, Map<Source, CompilationUnit>>{};
      for (var source in codeMap.keys) {
        var code = codeMap[source];
        var unit = parseText(code, experimentStatus: experimentStatus);
        libraryUnitMap[source] = {source: unit};
      }
  
      return link(
        AnalysisOptionsImpl(),
        sourceFactory,
        declaredVariables,
        [],
        libraryUnitMap,
      );
    }
  
    Map<Source, CompilationUnit> _unitsOfLibrary(
  
negative.code:       AnalysisOptionsImpl(),
        sourceFactory,
        declaredVariables,
        [sdkBundle],
        libraryUnitMap,
      );
  
  