Bug report

When using constant enums on function parameters, variables that are declared inside an exhaustive if statement are reported as might not be defined, even though it's certainly defined.

Code snippet that reproduces the problem

https://phpstan.org/r/4a1aeeb3-758f-4dc9-99ab-dee8055071c6

Expected output

There should be no error reported, as every case of the constant enum is covered by the if statement, and every branch of the if statement declares the $message variable