phpstan: Result cache not working?

I just updated my project to use PHPStan 0.12.12 and read your article.

Based on this I would expect that repeated analysis (without any changes in the code, composer.lock or anything else) should be nearly instant, right? Because all files should be in the result cache so PHPStan would have nothing to do.

Yet the analysis takes 6-7 seconds regardless on whether or not I run vendor/bin/phpstan clear-result-cache -c phpstan.neon first.

Yes it’s fast, I don’t mean to complain that it’s too slow or anything. I just expected the result cache to have some effect but can’t see any. ¯\_(ツ)_/¯