anchor.diff:  // for details. All rights reserved. Use of this source code is governed by a
   // BSD-style license that can be found in the LICENSE file.
   
  +import 'dart:convert';
   import 'dart:io' as io;
   
   import 'package:_fe_analyzer_shared/src/base/syntactic_entity.dart';
  
positive.code:       instances.putIfAbsent(elementKind, () => _ElementKind._(elementKind));
  
    _ElementKind._(this.elementKind);
  }
  
  /// A wrapper for a keyword to allow keywords and element kinds to be used as
  
negative.code:     var contextMap = byKind.putIfAbsent(context, () => {});
      var key = _Keyword(keyword);
      contextMap[key] = (contextMap[key] ?? 0) + 1;
    }
  
    /// Convert this data to a JSON encoded format.
    String toJson() {
      var map = <String, Map<String, String>>{};
      for (var contextEntry in byKind.entries) {
        var kindMap = <String, String>{};
        for (var kindEntry in contextEntry.value.entries) {
          kindMap[kindEntry.key.uniqueKey] = kindEntry.value.toString();
        }
        map[contextEntry.key] = kindMap;
      }
      return json.encode(map);
    }
  
    /// Add the data in the [source] map to the [target] map.
  