Issue #3178534: Start running PHPStan on Drupal core (level 0 - part 1)

composer/Metapackage/DevDependencies/composer.json

@@ -15,8 +15,11 @@
         "friends-of-behat/mink-browserkit-driver": "^1.4",
         "instaclick/php-webdriver": "^1.4.1",
         "justinrainbow/json-schema": "^5.2",
+        "mglaman/phpstan-drupal": "^1.0.3",
         "mikey179/vfsstream": "^1.6.8",
         "phpspec/prophecy": "^1.12",
+        "phpstan/extension-installer": "^1",
+        "phpstan/phpstan": "^1.1",
         "phpunit/phpunit": "^8.5.14 || ^9",
         "symfony/browser-kit": "^4.4",
         "symfony/css-selector": "^4.4",