diff --git a/lib/Runtime/Library/JavascriptArray.cpp b/lib/Runtime/Library/JavascriptArray.cpp
index 640618513e7..5cf0818493e 100644
--- a/lib/Runtime/Library/JavascriptArray.cpp
+++ b/lib/Runtime/Library/JavascriptArray.cpp
@@ -4252,7 +4252,7 @@ namespace Js
         [&](bool/*hasException*/)
         {
             Var top = scriptContext->PopObject();
-            if (JavascriptProxy::Is(thisArg))
+            if (isProxy)
             {
                 AssertMsg(top == target, "Unmatched operation stack");
             }