diff --git a/src/Framework/MockObject/MockMethod.php b/src/Framework/MockObject/MockMethod.php
index 39e7ac22d52..1d94d46b5e6 100644
--- a/src/Framework/MockObject/MockMethod.php
+++ b/src/Framework/MockObject/MockMethod.php
@@ -102,7 +102,7 @@ public static function fromReflection(ReflectionMethod $method, bool $callOrigin
         }
 
         if ($method->hasReturnType()) {
-            $returnType = (string) $method->getReturnType();
+            $returnType = $method->getReturnType()->getName();
         } else {
             $returnType = '';
         }
@@ -301,8 +301,8 @@ private static function getMethodParameters(ReflectionMethod $method, bool $forC
                     $nullable = '?';
                 }
 
-                if ($parameter->hasType() && (string) $parameter->getType() !== 'self') {
-                    $typeDeclaration = $parameter->getType() . ' ';
+                if ($parameter->hasType() && $parameter->getType()->getName() !== 'self') {
+                    $typeDeclaration = $parameter->getType()->getName() . ' ';
                 } else {
                     try {
                         $class = $parameter->getClass();