anchor.diff:      if (icon != null) {
         rowChildren.add(new SizedBox(
           width: 72.0,
  -        child: new Icon(icon: icon, color: Theme.of(context).disabledColor)
  +        child: new IconButton(icon: icon, onPressed: onPressed)
         ));
       }
       return new Padding(
  
positive.code:               icon: Icons.email,
                children: <Widget>[
                  new _ContactItem(
                    lines: <String>[
                      'ali_connors@example.com',
                      'Personal'
                    ]
                  ),
                  new _ContactItem(
                    lines: <String>[
                      'aliconnors@example.com',
                      'Work'
  
negative.code: }
  
  class _ContactItem extends StatelessWidget {
    _ContactItem({ Key key, this.icon, this.lines, this.tooltip, this.onPressed }) : super(key: key) {
      assert(lines.length > 1);
    }
  
    final IconData icon;
    final List<String> lines;
    final String tooltip;
    final VoidCallback onPressed;
  
    @override
    Widget build(BuildContext context) {
  