anchor.diff:  library linter.src.analysis;
   
   import 'dart:collection';
  -import 'dart:io';
  +import 'dart:io' as io;
   
   import 'package:analyzer/dart/element/element.dart';
   import 'package:analyzer/file_system/file_system.dart'
  -    show Folder, ResourceUriResolver;
  +    show File, Folder, ResourceUriResolver;
   import 'package:analyzer/file_system/physical_file_system.dart';
   import 'package:analyzer/source/package_map_provider.dart';
   import 'package:analyzer/source/package_map_resolver.dart';
  
positive.code: 
      List<Source> sources = [];
      ChangeSet changeSet = new ChangeSet();
      for (File file in files) {
        JavaFile sourceFile = new JavaFile(p.normalize(file.absolute.path));
        Source source = new FileBasedSource(sourceFile, sourceFile.toURI());
        Uri uri = context.sourceFactory.restoreUri(source);
        if (uri != null) {
          // Ensure that we analyze the file using its canonical URI (e.g. if
          // it's in "/lib", analyze it using a "package:" URI).
          source = new FileBasedSource(sourceFile, uri);
        }
        sources.add(source);
        changeSet.addedSource(source);
  
negative.code:       String packageConfigPath = options.packageConfigPath;
        Uri fileUri = new Uri.file(packageConfigPath);
        try {
          io.File configFile = new io.File.fromUri(fileUri).absolute;
          List<int> bytes = configFile.readAsBytesSync();
          Map<String, Uri> map = pkgfile.parse(bytes, configFile.uri);
          return new MapPackages(map);
  