diff --git a/Casbin/Model/PolicyScanner.cs b/Casbin/Model/PolicyScanner.cs
index 5ccc82b..542ef2d 100644
--- a/Casbin/Model/PolicyScanner.cs
+++ b/Casbin/Model/PolicyScanner.cs
@@ -22,7 +22,7 @@ public bool GetNext(out IPolicyValues outValues)
     private PolicyScanner _scanner;
     private readonly TRequest _request;
 
-    internal PolicyScanner(in PolicyScanner scanner, in TRequest request)
+    internal PolicyScanner(PolicyScanner scanner, in TRequest request)
     {
         _scanner = scanner;
         _request = request;