Why is the order of method calls important here?

[AnjaLiebermann]

This throws an error:
https://phpstan.org/r/5fb29d08-c399-4402-98f8-69b41b9d212d

while this is perfectly ok:
https://phpstan.org/r/3035c4cb-f8b6-4db9-b51c-2be34b8f3bed

Difference is the order of the called methods in the last lines.

Why, oh why? This error drove me nuts for weeks!

[Kocal]

Hi,

setCreatedOn() is a method from History and its return type is self. So even if you create a new class that extends History and call setCreatedOn, your typing tells PHPStan/PHP it will returns History instance but not ProfessionalActivityText.

Your second example is neither ok, $professionalActivity is also seen as History instance:

To get it working, you must change self to static, by using PHPDoc or use PHP 8.

This is a correct version of your code: https://phpstan.org/r/466b3f71-0a74-4fe1-a9ae-b4c1c436990b

[AnjaLiebermann]

If one sees it it is logical. I was hunting this for weeks and only today I realized, that the order of the calls in important, because in a similar class, which extends the same classes, I had the calls in the "correct" order. Mind: My code was always working php-wise.