diff --git a/src/php/Models/PHPClass.php b/src/php/Models/PHPClass.php
index cda6d12ecd387ee997b7b1955240021d975ab761..d664b892e7d0526b4d9b9d4c099d6d16ffb76a2b 100644
--- a/src/php/Models/PHPClass.php
+++ b/src/php/Models/PHPClass.php
@@ -95,7 +95,7 @@ final class PHPClass implements ClassName
         } elseif ($name instanceof \ReflectionClass) {
             $name = $name->getName();
         } elseif (!\is_string($name)) {
-            throw new InvalidArgumentException(__METHOD__ . " argument should be a string, ClassName or ReflectionClass, not $name");
+            throw new InvalidArgumentException(__METHOD__ . " argument should be a string, ClassName or ReflectionClass, not ". json_encode($name));
         }
 
         static $instances = [];