This class seems to be duplicated in your project.
Duplicated code is one of the most pungent code smells. If you need to duplicate
the same code in three or more different places, we strongly encourage you to
look into extracting the code into a single class or operation.
You can also find more detailed suggestions in the “Code” section of your repository.
It seems like \HansOtt\Holiday\getEndOfDay($startsAt) targeting HansOtt\Holiday\getEndOfDay() can also be of type false; however, HansOtt\Holiday\HolidayAbstract::__construct() does only seem to accept object<DateTimeImmutable>, did you maybe forget to handle an error condition?
Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation.
You can also find more detailed suggestions in the “Code” section of your repository.