anchor.diff:  
     @override
     Future<SourceChange> createChange() async {
  -    final DartChangeBuilder changeBuilder =
  -        new DartChangeBuilder(driver.currentSession);
  +    final ChangeBuilder changeBuilder = new ChangeBuilder();
       final CompilationUnitElement element = resolvedUnit.unit.declaredElement;
       if (element == null) {
         return changeBuilder.sourceChange;
       }
  -    final LibraryElement libraryElement = element.library;
  +
  +    var libraryElement = element.library;
  +    var libraryPath = libraryElement.source.fullName;
   
       // If this element is a library, update outgoing references inside the file.
       if (element == libraryElement.definingCompilationUnit) {
         // Handle part-of directives in this library
         final ResolvedLibraryResult libraryResult = await driver.currentSession
             .getResolvedLibraryByElement(libraryElement);
  +      ResolvedUnitResult definingUnitResult;
         for (ResolvedUnitResult result in libraryResult.units) {
           if (result.isPart) {
             Iterable<PartOfDirective> partOfs = result.unit.directives
  
positive.code: import 'package:analyzer/file_system/file_system.dart';
  import 'package:analyzer/src/dart/analysis/driver.dart';
  import 'package:analyzer/src/generated/source.dart';
  import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
  import 'package:path/path.dart' as pathos;
  
  /**
  
negative.code:             });
            }
          }
          if (result.path == libraryPath) {
            definingUnitResult = result;
          }
        }
  
        await changeBuilder.addFileEdit(definingUnitResult.path, (builder) {
          final String oldDir = pathContext.dirname(oldFile);
          final String newDir = pathContext.dirname(newFile);
          for (var directive in definingUnitResult.unit.directives) {
            if (directive is UriBasedDirective) {
              _updateUriReference(builder, directive, oldDir, newDir);
            }
          }
        });
      } else {
        // Otherwise, we need to update any relative part-of references.
  