interface.extendsDeprecatedTrait

Code example

<?php declare(strict_types = 1);

/** @deprecated Use NewHelper instead */
trait OldHelper
{
}

interface MyInterface extends OldHelper // ERROR: Interface MyInterface extends deprecated trait OldHelper.
{
}

Why is it reported?

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

An interface attempts to extend a trait that has been marked as deprecated with the @deprecated PHPDoc tag. While this is already invalid PHP (interfaces cannot extend traits), the deprecation rule also flags that the referenced trait is deprecated and should no longer be used.

How to fix it

Remove the deprecated trait from the extends clause and extend a proper interface instead:

 <?php declare(strict_types = 1);

-interface MyInterface extends OldHelper
+interface MyInterface extends NewHelperInterface
 {
 }