Cannot return objects in @dataProvider PHPUnit

Question

Is it allowed to return objects from @dataProviders to test methods?

public function iOsMessages()
{
    return [
        'update available'        => [1, new UpToDateMessage(), 'pl'],
    ];
}

/**
 * @test
 * @dataProvider iOsMessages
 */
public function success_create_message_for_ios(int $appVersion, MobileMessage $message, string $locale)
{
(...)

Error:

The data provider specified for Tests\Tests\Mobile\Classes\AppVersionTest::success_create_message_for_ios is invalid. Class 'Mobile\Classes\Messages\UpToDateMessage' not found

MobileMessage is an interface, imports are correct.

Answer 1

From the documentation:

A data provider method must be public and either return an array of arrays or an object that implements the Iterator interface and yields an array for each iteration step.