anchor.diff:  import 'package:analyzer/dart/analysis/results.dart';
   import 'package:analyzer/diagnostic/diagnostic.dart';
   import 'package:analyzer/error/error.dart' as err;
  +import 'package:analyzer/file_system/overlay_file_system.dart';
   import 'package:analyzer/file_system/physical_file_system.dart';
  +import 'package:analyzer/src/dart/analysis/driver_based_analysis_context.dart';
   import 'package:analyzer/src/generated/engine.dart';
   import 'package:args/args.dart';
   
  
positive.code:   print('Metrics computed in $duration');
    return io.exit(code);
  }
  
  /// Create a parser that can be used to parse the command-line arguments.
  ArgParser createArgParser() {
  
negative.code:     final collection = AnalysisContextCollection(
        includedPaths: root.includedPaths.toList(),
        excludedPaths: root.excludedPaths.toList(),
        resourceProvider: _provider,
      );
  
      var context = collection.contexts[0];
  //    // Set the DeclarationsTracker, only call doWork to build up the available
  //    // suggestions if doComputeCompletionsFromAnalysisServer is true.
  