anchor.diff:  /// An icon with one character
   class CircleIcon extends StatelessWidget {
     const CircleIcon({
  -    @required this.text,
  -    @required this.color,
  +    required this.text,
  +    required this.color,
     });
   
     /// Text to display. Should be one character.
  
positive.code: /*
   * Copyright 2017 The Chromium Authors. All rights reserved.
   * Use of this source code is governed by a BSD-style license that can be
  
negative.code: }
  
  class IconKind {
    const IconKind(this.name, this.icon, [AssetImageIcon? abstractIcon])
        : abstractIcon = abstractIcon ?? icon;
  
    static IconKind classIcon = const IconKind(
  