Bug report
This requires enabling strict rules, although strict rules doesn't seem to be the problem directly.
I'm not sure if this is intended or not, but it wasn't reported as an error before 2.x.
When the specific type of object isn't known, checking for isset on object can be used to inform its shape, so reporting an error about this doesn't make any sense to me.
Code snippet that reproduces the problem
https://phpstan.org/r/8bf0e12b-3cc8-4b4b-a086-2c4d15d5a7a1
Expected output
No error should be reported
Did PHPStan help you today? Did it make you happy in any way?
No response