diff --git a/src/PhpGenerator/Factory.php b/src/PhpGenerator/Factory.php
index 9509e763..b2854073 100644
--- a/src/PhpGenerator/Factory.php
+++ b/src/PhpGenerator/Factory.php
@@ -200,7 +200,7 @@ public function fromCallable(callable $from): Method|GlobalFunction|Closure
 	public function fromParameterReflection(\ReflectionParameter $from): Parameter
 	{
 		$param = $from->isPromoted()
-			? new PromotedParameter($from->name)
+			? (new PromotedParameter($from->name))->setReadOnly(PHP_VERSION_ID >= 80100 ? $from->getDeclaringClass()->getProperty($from->name)->isReadonly() : false)
 			: new Parameter($from->name);
 		$param->setReference($from->isPassedByReference());
 		$param->setType((string) $from->getType());
diff --git a/tests/PhpGenerator/ClassType.from.81.phpt b/tests/PhpGenerator/ClassType.from.81.phpt
index 6dd3db33..ce30dfc1 100644
--- a/tests/PhpGenerator/ClassType.from.81.phpt
+++ b/tests/PhpGenerator/ClassType.from.81.phpt
@@ -12,5 +12,7 @@ require __DIR__ . '/../bootstrap.php';
 require __DIR__ . '/fixtures/classes.81.php';
 
 $res[] = ClassType::from(new Abc\Class11);
+$res[] = ClassType::from(Abc\Attr::class);
+$res[] = ClassType::from(Abc\Class12::class);
 
 sameFile(__DIR__ . '/expected/ClassType.from.81.expect', implode("\n", $res));
diff --git a/tests/PhpGenerator/expected/ClassType.from.81.expect b/tests/PhpGenerator/expected/ClassType.from.81.expect
index f52acd06..22b0d789 100644
--- a/tests/PhpGenerator/expected/ClassType.from.81.expect
+++ b/tests/PhpGenerator/expected/ClassType.from.81.expect
@@ -16,3 +16,19 @@ class Class11
 	{
 	}
 }
+
+#[\Attribute]
+class Attr
+{
+}
+
+class Class12
+{
+	private readonly string $bar;
+
+
+	public function __construct(
+		public readonly string $foo,
+	) {
+	}
+}