diff --git a/js/xpconnect/src/XPCComponents.cpp b/js/xpconnect/src/XPCComponents.cpp
index 77df85b5f8024c67ebbeecfedcbffd738b3e5581..b69aaea0b5c21a5341e3bb0aad472d3169d2f6de 100644
--- a/js/xpconnect/src/XPCComponents.cpp
+++ b/js/xpconnect/src/XPCComponents.cpp
@@ -1789,7 +1789,7 @@ nsXPCComponents_Utils::GetFunctionSourceLocation(HandleValue funcValue,
     NS_ENSURE_TRUE(func, NS_ERROR_INVALID_ARG);
 
     RootedScript script(cx, JS_GetFunctionScript(cx, func));
-    NS_ENSURE_TRUE(func, NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE(script, NS_ERROR_FAILURE);
 
     AppendUTF8toUTF16(nsDependentCString(JS_GetScriptFilename(script)),
                       filename);