To use this extension, require it in Composer:
composer require --dev goetas/jms-serializer-phpstan-extension
If you also install phpstan/extension-installer then you're all set!
If you don't want to use phpstan/extension-installer, include extension.neon in your project's PHPStan config:
includes:
- vendor/goetas/jms-serializer-phpstan-extension/extension.neon