anchor.diff:  const int _kIntVal = 0;
   const double _kDoubleVal = 0.0;
   const bool _kBoolVal = true;
  +
  +int get _usageLineLength => stdout.hasTerminal ? stdout.terminalColumns : null;
   
   typedef ConvertYamlToType<T> = T Function(YamlMap, String, ResourceProvider);
   
  
positive.code: library dartdoc.dartdoc_options;
  
  import 'dart:async';
  import 'dart:io' show Platform;
  
  import 'package:analyzer/dart/element/element.dart';
  import 'package:analyzer/file_system/file_system.dart';
  
negative.code:           'dart.html',
            'dart.indexed_db',
            'dart.io',
            'dart.isolate',
            'dart.js',
            'dart.js_util',
            'dart.math',
  