Laravel undefined variable in Notification - laravel

Question

I'm experimenting with laravel and I came across this article.
I followed it exactly but for some reason when sending the mail in the Notification class, he can't find the $user variable I declared in the constructor. When printing it in the constructor it works so the user object is passed correctly, but when I want to access it in the toMail method, it's inexisting for some reason. Anyone know why & how to fix this?
<?php
namespace App\Notifications;
use App\User;
use Illuminate\Bus\Queueable;
use Illuminate\Notifications\Notification;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Messages\MailMessage;
class UserRegisteredSuccessfully extends Notification
{
use Queueable;
/**
* #var User
*/
protected $user;
/**
* Create a new notification instance.
*
* #param User $user
*/
public function __construct(User $user)
{
$this->$user = $user;
// printing here works
}
/**
* Get the notification's delivery channels.
*
* #param mixed $notifiable
* #return array
*/
public function via($notifiable)
{
return ['mail'];
}
/**
* Get the mail representation of the notification.
*
* #param mixed $notifiable
* #return \Illuminate\Notifications\Messages\MailMessage
*/
public function toMail($notifiable)
{
// ERROR HERE (Undefined variable: user)
$user = $this->$user;
return (new MailMessage)
->subject('Succesfully created new account')
->greeting(sprintf('Hello %s', $user->username))
->line('You have successfully registered to our system. Please activate your account.')
->action('Click here', route('activate.user', $user->activation_code))
->line('Thank you for using our application!');
}
/**
* Get the array representation of the notification.
*
* #param mixed $notifiable
* #return array
*/
public function toArray($notifiable)
{
return [
//
];
}
}
Register Method:
/**
* Register new user
*
* #param Request $request
* #return User
*/
protected function register(Request $request)
{
$validatedData = $request->validate([
'username' => 'required|string|max:255',
'email' => 'required|string|email|max:255|unique:users',
'password' => 'required|string|min:6|confirmed',
]);
try {
$validatedData['password'] = Hash::make(array_get($validatedData, 'password'));
$validatedData['activation_code'] = str_random(30).time();
$user = app(User::class)->create($validatedData);
} catch(\Exception $ex) {
logger()->error($ex);
return redirect()->back()->with('message', 'Unable to create new user.');
}
$user->notify(new UserRegisteredSuccessfully($user));
return redirect()->back()->with('message', 'Successfully created a new account. Please check your email and activate your account.');
}
Thanks in Advance!

Answer 1

You made 2 typos:
In your constructor:
$this->$user = $user;
Should be:
$this->user = $user;
And in the toMail() method:
$user = $this->$user;
Should be:
$user = $this->user;
The reason it is not working, is because you are currently using the value of $user as the variable name, and you are not assigning the value of the User object to $this->user.