Bug report

PHPStan - PHP Static Analysis Tool 0.12.58

Hi,
first, thank you for phpstan!
I switched to union types and got following error:

Parameter #2 $pathConstraint (array|string|null) of method Pipeline::pipe() is not contravariant with parameter #2 $pathConstraint (array|null|string|null) of method PipelineInterface::pipe().

Here is the code snippet.
https://phpstan.org/r/f4b0f601-2de8-401e-9460-bbf2a254acc1

May I am missing something but isn´t it valid?

Expected output

No error.