see #6440 maybe and https://phpstan.org/r/014f63ed-ee22-441c-b9db-bb80eae35d0c especially, I also only know the very rough edges of it. but having that in mind and taking a look at the implementation explains the "less annoying" parts :)

Yes, that shows it best. Another scenario is if you want to get rid of $result === false causing "$result can never be false" errors but at the same time you don't want to force everyone to eliminate false before returning string for example.

thank you both, that helps alot

ok thx, that should be enough for now at least. I came across 2 cases in some adaptions where it would think that array keys are strings for sure because of that. but simply not using toString() then should prevent that

hmm, just out of curiosity I removed BenevolentUnionType::unionResults and only 2 errors showed up in phpstans local test suite. One of them basically bringing back #5169 though which is kind of the same as https://phpstan.org/r/5a190fa6-8142-4cff-bade-f2c12fffc2a0.. I don't like this :/

maybe it makes still sense if the benevolent union results behaviour is not done for some is* Type methods? The inconsistency is a bit weird. I'm gonna try something..