It seems like $this->container->get(Ze...y\Configuration::class) can also be of type null; however, parameter $configuration of Zenstruck\Foundry\Factory::boot() does only seem to accept Zenstruck\Foundry\Configuration, maybe add an additional type check?
(
Ignorable by Annotation
)
If this is a false-positive, you can also ignore this issue in your code via the ignore-type annotation