Hide fixed invariance composition behind a bleeding-edge toggle

Author: jiripudil

conf/bleedingEdge.neon

@@ -24,3 +24,4 @@ parameters:
 		nullContextForVoidReturningFunctions: true
 		unescapeStrings: true
 		duplicateStubs: true
+		invarianceComposition: true

conf/config.neon

@@ -54,6 +54,7 @@ parameters:
 		nullContextForVoidReturningFunctions: false
 		unescapeStrings: false
 		duplicateStubs: false
+		invarianceComposition: false
 	fileExtensions:
 		- php
 	checkAdvancedIsset: false
@@ -272,6 +273,7 @@ parametersSchema:
 		nullContextForVoidReturningFunctions: bool()
 		unescapeStrings: bool()
 		duplicateStubs: bool()
+		invarianceComposition: bool()
 	])
 	fileExtensions: listOf(string())
 	checkAdvancedIsset: bool()

src/DependencyInjection/ContainerFactory.php

@@ -21,6 +21,7 @@
 use PHPStan\Reflection\ReflectionProvider;
 use PHPStan\Reflection\ReflectionProviderStaticAccessor;
 use PHPStan\Type\Accessory\AccessoryArrayListType;
+use PHPStan\Type\Generic\TemplateTypeVariance;
 use Symfony\Component\Finder\Finder;
 use function array_diff_key;
 use function array_map;
@@ -174,6 +175,7 @@ public static function postInitializeContainer(Container $container): void
 
 		BleedingEdgeToggle::setBleedingEdge($container->getParameter('featureToggles')['bleedingEdge']);
 		AccessoryArrayListType::setListTypeEnabled($container->getParameter('featureToggles')['listType']);
+		TemplateTypeVariance::setInvarianceCompositionEnabled($container->getParameter('featureToggles')['invarianceComposition']);
 	}
 
 	public function clearOldContainers(string $tempDirectory): void

src/Type/Generic/TemplateTypeVariance.php

@@ -21,6 +21,8 @@ class TemplateTypeVariance
 	/** @var self[] */
 	private static array $registry;
 
+	private static bool $invarianceCompositionEnabled = false;
+
 	private function __construct(private int $value)
 	{
 	}
@@ -93,7 +95,7 @@ public function compose(self $other): self
 			return self::createInvariant();
 		}
 
-		if ($this->invariant()) {
+		if (self::$invarianceCompositionEnabled && $this->invariant()) {
 			return self::createInvariant();
 		}
 
@@ -177,4 +179,9 @@ public static function __set_state(array $properties): self
 		return new self($properties['value']);
 	}
 
+	public static function setInvarianceCompositionEnabled(bool $enabled): void
+	{
+		self::$invarianceCompositionEnabled = $enabled;
+	}
+
 }