Bug report

PHPStan 0.12.7.

If a function argument type is enforced to be a string, its strict comparison with anything else than a string should be reported as useless.

Code snippet that reproduces the problem

https://phpstan.org/r/4b215575-9bb4-4928-a5b9-d993026000b8

Expected output

PHPStan should report the $database !== null as useless because it's always true.