diff --git a/lib/private/Lock/MemcacheLockingProvider.php b/lib/private/Lock/MemcacheLockingProvider.php
index b9c3e9954607c..7f540df59be93 100644
--- a/lib/private/Lock/MemcacheLockingProvider.php
+++ b/lib/private/Lock/MemcacheLockingProvider.php
@@ -44,7 +44,7 @@ public function __construct(
 		parent::__construct($ttl);
 	}
 
-	private function setTTL(string $path, int $ttl = null, ?int $compare = null): void {
+	private function setTTL(string $path, int $ttl = null, mixed $compare = null): void {
 		if (is_null($ttl)) {
 			$ttl = $this->ttl;
 		}