| 1 | <?php | ||
| 11 | class NotFoundException extends \Exception | ||
| 12 | { | ||
| 13 | /** | ||
| 14 | * NotFoundException constructor. | ||
| 15 | * @param string $message | ||
| 16 | * @param int $code | ||
| 17 | * @param Throwable|null $previous | ||
| 18 | */ | ||
| 19 | public function __construct($message = "", $code = 0, Throwable $previous = null) | ||
| 23 | |||
| 24 | /** | ||
| 25 | * @return string|void | ||
| 26 | */ | ||
| 27 | public function __toString() | ||
| 31 | |||
| 32 | /** | ||
| 33 | * | ||
| 34 | */ | ||
| 35 | public function __wakeup() | ||
| 39 | |||
| 40 | } | 
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different sub-classes of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the parent class: