diff --git a/Tests/Encoder/XmlEncoderTest.php b/Tests/Encoder/XmlEncoderTest.php
index e3b7376d2..075202160 100644
--- a/Tests/Encoder/XmlEncoderTest.php
+++ b/Tests/Encoder/XmlEncoderTest.php
@@ -933,7 +933,7 @@ private function createXmlEncoderWithDateTimeNormalizer(): XmlEncoder
     /**
      * @return MockObject&NormalizerInterface
      */
-    private function createMockDateTimeNormalizer()
+    private function createMockDateTimeNormalizer(): NormalizerInterface
     {
         $mock = $this->createMock(CustomNormalizer::class);
 
diff --git a/Tests/Normalizer/AbstractNormalizerTest.php b/Tests/Normalizer/AbstractNormalizerTest.php
index 7b3c0a0b0..5655b1643 100644
--- a/Tests/Normalizer/AbstractNormalizerTest.php
+++ b/Tests/Normalizer/AbstractNormalizerTest.php
@@ -36,7 +36,7 @@ class AbstractNormalizerTest extends TestCase
     private $normalizer;
 
     /**
-     * @var ClassMetadataFactoryInterface|MockObject
+     * @var MockObject&ClassMetadataFactoryInterface
      */
     private $classMetadata;
 
diff --git a/Tests/Normalizer/ArrayDenormalizerTest.php b/Tests/Normalizer/ArrayDenormalizerTest.php
index ff1f85a45..ffdb943c0 100644
--- a/Tests/Normalizer/ArrayDenormalizerTest.php
+++ b/Tests/Normalizer/ArrayDenormalizerTest.php
@@ -25,7 +25,7 @@ class ArrayDenormalizerTest extends TestCase
     private $denormalizer;
 
     /**
-     * @var SerializerInterface|MockObject
+     * @var MockObject&SerializerInterface
      */
     private $serializer;
 
diff --git a/Tests/Normalizer/JsonSerializableNormalizerTest.php b/Tests/Normalizer/JsonSerializableNormalizerTest.php
index 7731b9c50..e0222a5fa 100644
--- a/Tests/Normalizer/JsonSerializableNormalizerTest.php
+++ b/Tests/Normalizer/JsonSerializableNormalizerTest.php
@@ -31,7 +31,7 @@ class JsonSerializableNormalizerTest extends TestCase
     private $normalizer;
 
     /**
-     * @var MockObject|SerializerInterface
+     * @var MockObject&JsonSerializerNormalizer
      */
     private $serializer;