diff --git a/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php b/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php
index a61a1bd72013..fca34f837b0b 100644
--- a/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php
+++ b/src/Illuminate/Foundation/Http/Middleware/TransformsRequest.php
@@ -58,9 +58,11 @@ protected function cleanParameterBag(ParameterBag $bag)
      */
     protected function cleanArray(array $data, $keyPrefix = '')
     {
-        return collect($data)->map(function ($value, $key) use ($keyPrefix) {
-            return $this->cleanValue($keyPrefix.$key, $value);
-        })->all();
+        foreach ($data as $key => $value) {
+            $data[$key] = $this->cleanValue($keyPrefix.$key, $value);
+        }
+
+        return collect($data)->all();
     }
 
     /**