| 1 | <?php  | 
            ||
| 17 | class PurchaseResponse extends AbstractResponse implements RedirectResponseInterface  | 
            ||
| 18 | { | 
            ||
| 19 | protected $redirectUrl;  | 
            ||
| 20 | |||
| 21 | 2 | public function __construct(RequestInterface $request, $data, $redirectUrl)  | 
            |
| 27 | |||
| 28 | 1 | public function isSuccessful()  | 
            |
| 32 | |||
| 33 | 1 | public function isRedirect()  | 
            |
| 37 | |||
| 38 | public function getRedirectUrl()  | 
            ||
| 42 | |||
| 43 | 1 | public function getRedirectMethod()  | 
            |
| 47 | |||
| 48 | 1 | public function getRedirectData()  | 
            |
| 52 | }  | 
            ||
| 53 | 
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 implementation 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 interface: