anchor.diff:    }
   
     /**
  -   * Return the [Source] for the given [path] in [_sourceFactory].
  -   */
  -  Source _sourceForPath(String path) {
  +   * Return the default [Uri] for the given path in [_sourceFactory].
  +   */
  +  Uri _uriForPath(String path) {
       Source fileSource = _resourceProvider.getFile(path).createSource();
  -    Uri uri = _sourceFactory.restoreUri(fileSource);
  -    return _resourceProvider.getFile(path).createSource(uri);
  +    return _sourceFactory.restoreUri(fileSource);
     }
   }
  
positive.code: import 'package:analyzer/src/generated/engine.dart';
  import 'package:analyzer/src/generated/parser.dart';
  import 'package:analyzer/src/generated/source.dart';
  import 'package:analyzer/src/summary/format.dart';
  import 'package:analyzer/src/summary/idl.dart';
  import 'package:analyzer/src/summary/summarize_ast.dart';
  import 'package:convert/convert.dart';
  import 'package:crypto/crypto.dart';
  
  
negative.code:    * Return the [FileState] for the give [path]. The returned file has the
     * last known state since if was last refreshed.
     */
    FileState getFile(String path, [Uri uri]) {
      FileState file = _pathToFile[path];
      if (file == null) {
        uri ??= _uriForPath(path);
        file = new FileState(this, path, uri);
        _pathToFile[path] = file;
        file.refresh();
      }
  