Looks like there is an issue with phpstan type definition, specifically &Proxy<T> part breaking extension chain resolving to Factory<T>.
I don't understand why T&Proxy<T> is a not a subtype of object.
Is this a problem in PhpStan itself?
Minimal reproducer https://phpstan.org/r/eece4718-641c-4e5b-bac9-e4f1430f8fda
Just as a test - removing &Proxy<T> part from PersistentProxyObjectFactory makes PhpStan happy.
https://phpstan.org/r/dc467615-ce04-4f6c-8370-b6be346ec8c0