diff --git a/system/Session/Session.php b/system/Session/Session.php
index 8e845462065b..4c6f39ec9c0e 100644
--- a/system/Session/Session.php
+++ b/system/Session/Session.php
@@ -723,9 +723,9 @@ public function markAsFlashdata($key): bool
 	{
 		if (is_array($key))
 		{
-			for ($i = 0, $c = count($key); $i < $c; $i ++)
+			foreach ($key as $sessionKey)
 			{
-				if (! isset($_SESSION[$key[$i]]))
+				if (! isset($_SESSION[$sessionKey]))
 				{
 					return false;
 				}