anchor.diff:  
   import 'dart:io';
   
  +import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
   import 'package:analyzer/dart/analysis/features.dart';
   import 'package:analyzer/dart/analysis/results.dart';
   import 'package:analyzer/dart/analysis/utilities.dart';
  
positive.code: Future<bool> validateLibrary(Directory dir) async {
    final libName = path.basename(dir.path);
  
    print('## dart:$libName');
    print('');
  
  
negative.code:   final StringBuffer errors = StringBuffer();
  
    ValidateCommentCodeSamplesVisitor(
      this.analysisHelper,
      this.coreLibName,
      this.filePath,
      this.lineInfo,
  