Fix false positive about private service in service subscriber

Author: jeroennoten

src/Rules/Symfony/ContainerInterfacePrivateServiceRule.php

@@ -8,7 +8,9 @@
 use PHPStan\Rules\Rule;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Symfony\ServiceMap;
+use PHPStan\TrinaryLogic;
 use PHPStan\Type\ObjectType;
+use PHPStan\Type\Type;
 use function sprintf;
 
 /**
@@ -53,7 +55,7 @@ public function processNode(Node $node, Scope $scope): array
 
 		$isTestContainerType = (new ObjectType('Symfony\Bundle\FrameworkBundle\Test\TestContainer'))->isSuperTypeOf($argType);
 		$isOldServiceSubscriber = (new ObjectType('Symfony\Component\DependencyInjection\ServiceSubscriberInterface'))->isSuperTypeOf($argType);
-		$isServiceSubscriber = (new ObjectType('Symfony\Contracts\Service\ServiceSubscriberInterface'))->isSuperTypeOf($argType);
+		$isServiceSubscriber = $this->isServiceSubscriber($argType, $scope);
 		$isServiceLocator = (new ObjectType('Symfony\Component\DependencyInjection\ServiceLocator'))->isSuperTypeOf($argType);
 		if ($isTestContainerType->yes() || $isOldServiceSubscriber->yes() || $isServiceSubscriber->yes() || $isServiceLocator->yes()) {
 			return [];
@@ -83,4 +85,12 @@ public function processNode(Node $node, Scope $scope): array
 		return [];
 	}
 
+	private function isServiceSubscriber(Type $containerType, Scope $scope): TrinaryLogic
+	{
+		$serviceSubscriberInterfaceType = new ObjectType('Symfony\Contracts\Service\ServiceSubscriberInterface');
+		$containedClassType = new ObjectType($scope->getClassReflection()->getName());
+		return $serviceSubscriberInterfaceType->isSuperTypeOf($containerType)
+			->or($serviceSubscriberInterfaceType->isSuperTypeOf($containedClassType));
+	}
+
 }

tests/Rules/Symfony/ExampleServiceSubscriber.php

@@ -2,14 +2,25 @@
 
 namespace PHPStan\Rules\Symfony;
 
+use Psr\Container\ContainerInterface;
 use Symfony\Contracts\Service\ServiceSubscriberInterface;
 
 final class ExampleServiceSubscriber implements ServiceSubscriberInterface
 {
+	/**
+	 * @var ContainerInterface
+	 */
+	private $locator;
+
+	public function __construct(ContainerInterface $locator)
+	{
+		$this->locator = $locator;
+	}
 
 	public function privateService(): void
 	{
 		$this->get('private');
+		$this->locator->get('private');
 	}
 
 	public function containerParameter(): void