anchor.diff:                                "${provider.displayName == null ? "" : "Name: ${provider.displayName}\n"}"),
                           ),
                         ),
  -                      onDismissed: (action) =>
  -                          widget.user.unlink(provider.providerId),
                       ),
                   ],
                 ),
               Visibility(
                 visible: widget.user != null,
                 child: Container(
  -                margin: EdgeInsets.only(top: 8.0),
  +                margin: const EdgeInsets.only(top: 8),
                   alignment: Alignment.center,
                   child: Row(
                     mainAxisAlignment: MainAxisAlignment.spaceEvenly,
  
positive.code:                 photoURL: _urlController.text);
              Navigator.of(context).pop();
            },
            child: const Text("Update"),
          )
        ],
      );
  
negative.code:   Widget build(BuildContext context) {
      return Card(
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Container(
                padding: const EdgeInsets.only(bottom: 8),
                alignment: Alignment.center,
                child: const Text(
                  'User info',
                  style: TextStyle(fontWeight: FontWeight.bold),
                ),
              ),
              if (widget.user != null)
                if (widget.user.photoURL != null)
                  Container(
                    alignment: Alignment.center,
                    margin: const EdgeInsets.only(bottom: 8),
                    child: Image.network(widget.user.photoURL),
                  )
                else
                  Align(
                    child: Container(
                      padding: const EdgeInsets.all(8),
                      margin: const EdgeInsets.only(bottom: 8),
                      color: Colors.black,
                      child: const Text(
                        'No image',
                        textAlign: TextAlign.center,
                      ),
                    ),
                  ),
              Text(widget.user == null
  