Bug report

I suspect that some optimisation about array is creating an issue
@ondrejmirtes @rvanvelzen

Code snippet that reproduces the problem

https://phpstan.org/r/7aacecc5-cd35-4ec4-98ae-c70b4635e1ef

Doing things on one key of the array is automatically changing the way phpstan is inferring the other key (and the whole array).

Expected output

No errors.