The expression parent::getMatcher($matcherIdentifier); of type eZ\Publish\Core\MVC\Symf...er\ViewMatcherInterface adds the type eZ\Publish\Core\MVC\Symf...er\ViewMatcherInterface to the return on line 32 which is incompatible with the return type documented by eZ\Bundle\EzPublishCoreB...cherFactory::getMatcher of type eZ\Publish\Core\MVC\Symf...tBased\MatcherInterface.