traitUse.deprecatedInterface

Code example

<?php declare(strict_types = 1);

namespace App;

/** @deprecated Use NewInterface instead */
interface OldInterface
{
    public function doSomething(): void;
}

class Foo
{
    use OldInterface;
}

Why is it reported?

This error is reported by the phpstan/phpstan-deprecation-rules package.

The use statement inside a class body references an interface that is marked as @deprecated. While using an interface in a use statement is already incorrect (interfaces cannot be used as traits), the deprecation error is also reported because the referenced symbol is deprecated.

How to fix it

Interfaces should be implemented using the implements keyword, not use. Replace the trait use with a proper implements declaration using the non-deprecated replacement:

 <?php declare(strict_types = 1);

 namespace App;

-class Foo
+class Foo implements NewInterface
 {
-    use OldInterface;
+    public function doSomething(): void
+    {
+        // ...
+    }
 }

If the class is itself deprecated, the error will not be reported:

 <?php declare(strict_types = 1);

 namespace App;

+/** @deprecated */
 class Foo
 {
     use OldInterface;
 }