PHPStan fail to detect unused methods.

Code snippet that reproduces the problem
https://phpstan.org/r/ec096166-959b-4a45-906c-b43b84b3503d

Expected output

Line	Error
9	Method HelloWorld::getTest() is unused.
20	Method HelloWorld::getTest1() is unused.

Notes

If we edit the first function to return only ONE string
https://phpstan.org/r/836038c0-c7f9-4bcd-9894-63fb7cec137a
the errors are detected successfully.