Use declared property type instead of scope-narrowed type when inferring generic new expression types

- In `NewHandler::exactInstantiation()`, when `new GenericClass()` is assigned
  to a property and the constructor cannot resolve template types, the code
  infers template types from the property's declared type
- Previously used `$scope->getType($assignedToProperty)` which returns the
  scope-narrowed type — inside `if ($x === null)`, this returns `null`, and
  after `removeNull` becomes `never`, causing incorrect type inference
- Now uses `PropertyReflectionFinder::findPropertyReflectionFromNode()` to get
  the property's declared writable type, which is not affected by scope narrowing
- Affects both static and instance properties with nullable generic types like
  `WeakMap<object, string>|null` and `SplObjectStorage<object, string>|null`

Author: github-actions[bot]

src/Analyser/ExprHandler/NewHandler.php

@@ -35,6 +35,7 @@
 use PHPStan\Reflection\ParametersAcceptor;
 use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Rules\Properties\PropertyReflectionFinder;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\ErrorType;
 use PHPStan\Type\Generic\GenericObjectType;
@@ -66,6 +67,7 @@ public function __construct(
 		private ReflectionProvider $reflectionProvider,
 		private DynamicThrowTypeExtensionProvider $dynamicThrowTypeExtensionProvider,
 		private DynamicReturnTypeExtensionRegistryProvider $dynamicReturnTypeExtensionRegistryProvider,
+		private PropertyReflectionFinder $propertyReflectionFinder,
 		#[AutowiredParameter(ref: '%exceptions.implicitThrows%')]
 		private bool $implicitThrows,
 	)
@@ -416,10 +418,13 @@ private function exactInstantiation(MutatingScope $scope, New_ $node, Name $clas
 				$classTemplateTypes = $traverser->getClassTemplateTypes();
 
 				if (count($classTemplateTypes) === count($originalClassTemplateTypes)) {
-					$propertyType = TypeCombinator::removeNull($scope->getType($assignedToProperty));
-					$nonFinalObjectType = $isStatic ? new StaticType($nonFinalClassReflection) : new ObjectType($resolvedClassName, classReflection: $nonFinalClassReflection);
-					if ($nonFinalObjectType->isSuperTypeOf($propertyType)->yes()) {
-						return $propertyType;
+					$foundProperty = $this->propertyReflectionFinder->findPropertyReflectionFromNode($assignedToProperty, $scope);
+					if ($foundProperty !== null) {
+						$propertyType = TypeCombinator::removeNull($foundProperty->getWritableType());
+						$nonFinalObjectType = $isStatic ? new StaticType($nonFinalClassReflection) : new ObjectType($resolvedClassName, classReflection: $nonFinalClassReflection);
+						if ($nonFinalObjectType->isSuperTypeOf($propertyType)->yes()) {
+							return $propertyType;
+						}
 					}
 				}
 			}

tests/PHPStan/Analyser/nsrt/bug-11844.php

@@ -0,0 +1,36 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug11844Nsrt;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+	/**
+	 * @var \WeakMap<object, string>|null
+	 */
+	private static ?\WeakMap $staticMap = null;
+
+	/**
+	 * @var \WeakMap<object, string>|null
+	 */
+	private ?\WeakMap $instanceMap = null;
+
+	public static function initStatic(): void
+	{
+		if (self::$staticMap === null) {
+			self::$staticMap = new \WeakMap();
+			assertType('WeakMap<object, string>', self::$staticMap);
+		}
+	}
+
+	public function initInstance(): void
+	{
+		if ($this->instanceMap === null) {
+			$this->instanceMap = new \WeakMap();
+			assertType('WeakMap<object, string>', $this->instanceMap);
+		}
+	}
+}

tests/PHPStan/Rules/TooWideTypehints/TooWidePropertyTypeRuleTest.php

@@ -138,4 +138,10 @@ public function testBug13624(): void
 		$this->analyse([__DIR__ . '/data/bug-13624.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug11844(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-11844.php'], []);
+	}
+
 }

tests/PHPStan/Rules/TooWideTypehints/data/bug-11844.php

@@ -0,0 +1,62 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug11844;
+
+class StaticPropertyCase
+{
+	/**
+	 * @var \WeakMap<object, string>|null
+	 */
+	private static ?\WeakMap $map = null;
+
+	public static function init(): void
+	{
+		if (self::$map === null) {
+			self::$map = new \WeakMap();
+		}
+	}
+}
+
+class InstancePropertyCase
+{
+	/**
+	 * @var \WeakMap<object, string>|null
+	 */
+	private ?\WeakMap $map = null;
+
+	public function init(): void
+	{
+		if ($this->map === null) {
+			$this->map = new \WeakMap();
+		}
+	}
+}
+
+/** @template T */
+class GenericContainer
+{
+	/** @var T */
+	private $value;
+
+	/** @param T $value */
+	public function __construct($value) {
+		$this->value = $value;
+	}
+}
+
+class OtherGenericCase
+{
+	/**
+	 * @var \SplObjectStorage<object, string>|null
+	 */
+	private static ?\SplObjectStorage $storage = null;
+
+	public static function init(): void
+	{
+		if (self::$storage === null) {
+			self::$storage = new \SplObjectStorage();
+		}
+	}
+}