diff --git a/Debug/DataCollector.php b/Debug/DataCollector.php
index ab953782..b872572c 100644
--- a/Debug/DataCollector.php
+++ b/Debug/DataCollector.php
@@ -42,7 +42,7 @@ public function __construct(
         $this->reset();
     }
 
-    public function collect(Request $request, Response $response, \Throwable $exception = null): void
+    public function collect(Request $request, Response $response, ?\Throwable $exception = null): void
     {
     }