feat: Use null|TData when the initial data is null

Author: siketyan

stubs/Symfony/Component/Form/FormFactoryInterface.stub

@@ -14,7 +14,7 @@ interface FormFactoryInterface
 	 * @param TData $data
 	 * @param array<string, mixed> $options
 	 *
-	 * @phpstan-return FormInterface<TData>
+	 * @phpstan-return ($data is null ? FormInterface<null|TData> : FormInterface<TData>)
 	 *
 	 * @throws \Symfony\Component\OptionsResolver\Exception\InvalidOptionsException
 	 */
@@ -27,8 +27,8 @@ interface FormFactoryInterface
 	 * @param class-string<TFormType> $type
 	 * @param TData $data
 	 * @param array<string, mixed> $options
-	 *
-	 * @phpstan-return FormInterface<TData>
+     *
+     * @phpstan-return ($data is null ? FormInterface<null|TData> : FormInterface<TData>)
 	 *
 	 * @throws \Symfony\Component\OptionsResolver\Exception\InvalidOptionsException
 	 */

tests/Stubs/Symfony/Component/Form/FormFactoryAwareClass.php

@@ -22,9 +22,22 @@ public function doSomething(): void
 		$form = $this->formFactory->create(DataClassType::class, new DataClass());
 		$data = $form->getData();
 		$this->thisOnlyAcceptsDataClass($data);
+		$this->thisOnlyAcceptsDataClassOrNull($data);
+	}
+
+	public function doSomethingNullable(): void
+	{
+		$form = $this->formFactory->create(DataClassType::class);
+		$data = $form->getData();
+		// $this->thisOnlyAcceptsDataClass($data); // ERROR!
+		$this->thisOnlyAcceptsDataClassOrNull($data);
 	}
 
 	private function thisOnlyAcceptsDataClass(DataClass $data): void
 	{
 	}
+
+	private function thisOnlyAcceptsDataClassOrNull(?DataClass $data): void
+	{
+	}
 }