diff --git a/js/xpconnect/src/XPCQuickStubs.h b/js/xpconnect/src/XPCQuickStubs.h
index ab9dc61bcec8..2c3b7317c6b1 100644
--- a/js/xpconnect/src/XPCQuickStubs.h
+++ b/js/xpconnect/src/XPCQuickStubs.h
@@ -435,49 +435,43 @@ castNativeFromWrapper(JSContext *cx,
             return nullptr;
     }
 
-    *rv = NS_ERROR_XPC_BAD_CONVERT_JS;
-
     nsISupports *native;
     if (wrapper) {
         native = wrapper->GetIdentityObject();
         cur = wrapper->GetFlatJSObject();
         if (!native || !HasBitInInterfacesBitmap(cur, interfaceBit)) {
-            return nullptr;
+            native = nullptr;
+        } else if (lccx) {
+            lccx->SetWrapper(wrapper, tearoff);
         }
-    } else if (cur) {
-        if (IS_SLIM_WRAPPER(cur)) {
-            native = static_cast<nsISupports*>(xpc_GetJSPrivate(cur));
-            if (!native || !HasBitInInterfacesBitmap(cur, interfaceBit)) {
-                return nullptr;
-            }
-        } else if (protoDepth >= 0) {
-            const mozilla::dom::DOMClass* domClass;
-            mozilla::dom::DOMObjectSlot slot =
-                mozilla::dom::GetDOMClass(cur, domClass);
-            native = mozilla::dom::UnwrapDOMObject<nsISupports>(cur, slot);
-            if (!native ||
-                (uint32_t)domClass->mInterfaceChain[protoDepth] != protoID) {
-                return nullptr;
-            }
-        } else {
-            return nullptr;
+    } else if (cur && IS_SLIM_WRAPPER(cur)) {
+        native = static_cast<nsISupports*>(xpc_GetJSPrivate(cur));
+        if (!native || !HasBitInInterfacesBitmap(cur, interfaceBit)) {
+            native = nullptr;
+        } else if (lccx) {
+            lccx->SetWrapper(cur);
+        }
+    } else if (cur && protoDepth >= 0) {
+        const mozilla::dom::DOMClass* domClass;
+        mozilla::dom::DOMObjectSlot slot =
+            mozilla::dom::GetDOMClass(cur, domClass);
+        native = mozilla::dom::UnwrapDOMObject<nsISupports>(cur, slot);
+        if (native &&
+            (uint32_t)domClass->mInterfaceChain[protoDepth] != protoID) {
+            native = nullptr;
         }
     } else {
-        return nullptr;
+        native = nullptr;
     }
 
-    *pRef = nullptr;
-    *pVal = OBJECT_TO_JSVAL(cur);
-
-    if (lccx) {
-        if (wrapper)
-            lccx->SetWrapper(wrapper, tearoff);
-        else if (IS_SLIM_WRAPPER(cur))
-            lccx->SetWrapper(cur);
+    if (native) {
+        *pRef = nullptr;
+        *pVal = OBJECT_TO_JSVAL(cur);
+        *rv = NS_OK;
+    } else {
+        *rv = NS_ERROR_XPC_BAD_CONVERT_JS;
     }
 
-    *rv = NS_OK;
-
     return native;
 }