diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index a0bf837..f335728 100755
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -22,6 +22,7 @@
             <directory suffix="Test.php">tests/Test</directory>
             <directory phpVersion="7.2" phpVersionOperator=">=">./tests/TestPhp72</directory>
             <directory phpVersion="7.4" phpVersionOperator=">=">./tests/TestPhp74</directory>
+            <directory phpVersion="8.0" phpVersionOperator=">=">./tests/TestPhp80</directory>
             <directory phpVersion="8.1" phpVersionOperator=">=">./tests/TestPhp81</directory>
             <directory phpVersion="8.2" phpVersionOperator=">=">./tests/TestPhp82</directory>
         </testsuite>
diff --git a/src/Metadata/Driver/AnnotationsDriver.php b/src/Metadata/Driver/AnnotationsDriver.php
index 8175bac..6109c45 100644
--- a/src/Metadata/Driver/AnnotationsDriver.php
+++ b/src/Metadata/Driver/AnnotationsDriver.php
@@ -151,9 +151,8 @@ private function getPropertyAnnotations(ReflectionProperty $property): array
         }
 
         // Adding php type if no precision has been added with annotation
-        if (PHP_VERSION_ID >= 70400 && $property->hasType() && !isset($annotations['type'])) {
-            /** @psalm-suppress UndefinedMethod */
-            $annotations['type'] = $this->findType($property->getType()->getName(), $property);
+        if (PHP_VERSION_ID >= 70400 && ($type = $property->getType()) && $type instanceof \ReflectionNamedType && !isset($annotations['type'])) {
+            $annotations['type'] = $this->findType($type->getName(), $property);
         }
 
         return $annotations;
diff --git a/tests/TestPhp80/Fixtures/with_union_type.php b/tests/TestPhp80/Fixtures/with_union_type.php
new file mode 100644
index 0000000..6b3337a
--- /dev/null
+++ b/tests/TestPhp80/Fixtures/with_union_type.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Bdf\Serializer\TestPhp80\Metadata\Driver\Bdf;
+
+class WithUnionType
+{
+    private int|string $id;
+
+    public function __construct(int|string $id)
+    {
+        $this->id = $id;
+    }
+
+    public function id(): int|string
+    {
+        return $this->id;
+    }
+}
diff --git a/tests/TestPhp80/Metadata/Driver/AnnotationsDriverTest.php b/tests/TestPhp80/Metadata/Driver/AnnotationsDriverTest.php
new file mode 100644
index 0000000..f7403a9
--- /dev/null
+++ b/tests/TestPhp80/Metadata/Driver/AnnotationsDriverTest.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Bdf\Serializer\TestPhp80\Metadata\Driver;
+
+use Bdf\Serializer\Metadata\ClassMetadata;
+use Bdf\Serializer\Metadata\Driver\AnnotationsDriver;
+use Bdf\Serializer\TestPhp80\Metadata\Driver\Bdf\WithUnionType;
+use Bdf\Serializer\Type\Type;
+use PHPUnit\Framework\TestCase;
+use ReflectionClass;
+
+
+/**
+ *
+ */
+class AnnotationsDriverTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        include_once __DIR__.'/../../Fixtures/with_union_type.php';
+    }
+
+    public function test_load_annotations()
+    {
+        $driver = new AnnotationsDriver();
+
+        $reflection = new ReflectionClass(WithUnionType::class);
+        $metadata = $driver->getMetadataForClass($reflection);
+
+        $this->assertInstanceOf(ClassMetadata::class, $metadata);
+        $this->assertEquals(WithUnionType::class, $metadata->name());
+
+        $this->assertEquals(Type::MIXED, $metadata->property('id')->type()->name());
+    }
+}