Type-specifying extension for ReflectionClass::isSubclassOf()

conf/config.neon

@@ -1024,6 +1024,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\ReflectionClassIsSubclassOfTypeSpecifyingExtension
+		tags:
+			- phpstan.typeSpecifier.methodTypeSpecifyingExtension
+
 	-
 		class: PHPStan\Type\Php\ReplaceFunctionsDynamicReturnTypeExtension
 		tags:

src/Testing/TestCase.php

@@ -628,8 +628,8 @@ public function createTypeSpecifier(
 			$printer,
 			$reflectionProvider,
 			self::getContainer()->getServicesByTag(TypeSpecifierFactory::FUNCTION_TYPE_SPECIFYING_EXTENSION_TAG),
-			$methodTypeSpecifyingExtensions,
-			$staticMethodTypeSpecifyingExtensions
+			array_merge($methodTypeSpecifyingExtensions, self::getContainer()->getServicesByTag(TypeSpecifierFactory::METHOD_TYPE_SPECIFYING_EXTENSION_TAG)),
+			array_merge($staticMethodTypeSpecifyingExtensions, self::getContainer()->getServicesByTag(TypeSpecifierFactory::STATIC_METHOD_TYPE_SPECIFYING_EXTENSION_TAG)),
 		);
 	}
 

src/Type/Php/ReflectionClassIsSubclassOfTypeSpecifyingExtension.php

@@ -0,0 +1,55 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Analyser\SpecifiedTypes;
+use PHPStan\Analyser\TypeSpecifier;
+use PHPStan\Analyser\TypeSpecifierAwareExtension;
+use PHPStan\Analyser\TypeSpecifierContext;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\MethodTypeSpecifyingExtension;
+use PHPStan\Type\ObjectType;
+
+class ReflectionClassIsSubclassOfTypeSpecifyingExtension implements MethodTypeSpecifyingExtension, TypeSpecifierAwareExtension
+{
+
+	private TypeSpecifier $typeSpecifier;
+
+	public function setTypeSpecifier(TypeSpecifier $typeSpecifier): void
+	{
+		$this->typeSpecifier = $typeSpecifier;
+	}
+
+	public function getClass(): string
+	{
+		return \ReflectionClass::class;
+	}
+
+	public function isMethodSupported(MethodReflection $methodReflection, MethodCall $node, TypeSpecifierContext $context): bool
+	{
+		return $methodReflection->getName() === 'isSubclassOf'
+			&& isset($node->args[0])
+			&& $context->true();
+	}
+
+	public function specifyTypes(MethodReflection $methodReflection, MethodCall $node, Scope $scope, TypeSpecifierContext $context): SpecifiedTypes
+	{
+		$valueType = $scope->getType($node->args[0]->value);
+		if (!$valueType instanceof ConstantStringType) {
+			return new SpecifiedTypes([], []);
+		}
+
+		return $this->typeSpecifier->create(
+			$node->var,
+			new GenericObjectType(\ReflectionClass::class, [
+				new ObjectType($valueType->getValue()),
+			]),
+			$context
+		);
+	}
+
+}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -10892,6 +10892,11 @@ public function dataBug4573(): array
 		return $this->gatherAssertTypes(__DIR__ . '/data/bug-4573.php');
 	}
 
+	public function dataBug4577(): array
+	{
+		return $this->gatherAssertTypes(__DIR__ . '/data/bug-4577.php');
+	}
+
 	/**
 	 * @param string $file
 	 * @return array<string, mixed[]>
@@ -11132,6 +11137,7 @@ private function gatherAssertTypes(string $file): array
 	 * @dataProvider dataBug2112
 	 * @dataProvider dataArrayMapClosure
 	 * @dataProvider dataBug4573
+	 * @dataProvider dataBug4577
 	 * @param string $assertType
 	 * @param string $file
 	 * @param mixed ...$args

tests/PHPStan/Analyser/data/bug-4577.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace Bug4577;
+
+use function PHPStan\Analyser\assertType;
+
+class Test
+{
+
+	public function test(\ReflectionClass $refClass): void
+	{
+		if ($refClass->isSubclassOf(Test::class)) {
+			$instance = $refClass->newInstance();
+			assertType(Test::class, $instance);
+		}
+	}
+
+}