Bug report

Offset type access M[K] in a conditional return results in an error.

p.s. specifying K of key-of<M> instead of K of string returns a union of all values in M

Code snippet that reproduces the problem

https://phpstan.org/r/e6243b1d-b497-4d28-9a4e-be12f69f34d9

Expected output

Line 33: Dumped Type: 2