anchor.diff:  
   library analyzer.src.generated.sdk_io;
   
  +import 'dart:collection';
   import 'dart:io';
   
   import 'package:analyzer/src/context/context.dart';
  
positive.code: 
    @override
    Source mapDartUri(String dartUri) {
      String libraryName;
      String relativePath;
      int index = dartUri.indexOf('/');
  
negative.code:   /**
     * Return the directory within the SDK directory that contains the libraries.
     */
    JavaFile get libraryDirectory {
      if (_libraryDirectory == null) {
        _libraryDirectory =
            new JavaFile.relative(_sdkDirectory, _LIB_DIRECTORY_NAME);
      }
      return _libraryDirectory;
    }
  
    /**
     * Return the file containing the Pub executable, or `null` if it does not exist.
  