PHPStan
Dscover bugs in your code without running it!
PHPStan finds bugs in your code without writing tests. It's open-source and free. PHPStan scans your whole codebase and looks for both obvious & tricky bugs. Even in those rarely executed if statements that certainly aren't covered by tests. You can run it on your machine and in CI to prevent those bugs ever reaching your customers in production. Thanks to rule levels you don't get overwhelmed with thousands of errors on the first run. You can increase PHPStan's capabilities on your code...