If you want to install the extension in an existing Magento application, you might need to upgrade to PHPStan 1.8 first by running the following command:
composer.phar require --dev phpstan/phpstan
Once you have updated PHPStan, you can install the extension by running this command:
composer.phar require --dev bitexpert/phpstan-magento
To make PHPStan aware of the extension, the best is to also install the
phpstan/extension-installer package which
will autodetect any PHPStan extension automatically and register it with PHPStan:
composer.phar require --dev phpstan/extension-installer
To have a look at what the extension can do for you, check the docs in the GitHub repository.
And finally, thanks to all users of the extension. Up to this day, we have about 475K downloads with roughly 900 - 1000 installations per day. This is crazy!