Discover bugs in code without running it...

I came across this interesting PHP tool that may be helpful to the CI community. I personally have not used it but that doesn't mean it's not worth a look.
https://phpstan.org/
DESCRIPTION: PHPStan focuses on finding errors in your code without actually running it. It catches whole classes of bugs even before you write tests for the code. It moves PHP closer to compiled languages in the sense that the correctness of each line of the code can be checked before you run the actual line.