--- a/js/src/jsproxy.cpp
+++ b/js/src/jsproxy.cpp
@@ -1466,20 +1466,21 @@ ReportInvalidTrapResult(JSContext *cx, J
         return;
     js_ReportValueError2(cx, JSMSG_INVALID_TRAP_RESULT, JSDVG_IGNORE_STACK, v,
                          NullPtr(), bytes.ptr());
 }
 
 // This function is shared between getOwnPropertyNames, enumerate, and keys
 static bool
 ArrayToIdVector(JSContext *cx, HandleObject proxy, HandleObject target, HandleValue v,
-                AutoIdVector &props, unsigned flags, JSAtom *trapName)
+                AutoIdVector &props, unsigned flags, JSAtom *trapName_)
 {
     JS_ASSERT(v.isObject());
     RootedObject array(cx, &v.toObject());
+    RootedAtom trapName(cx, trapName_);
 
     // steps g-h
     uint32_t n;
     if (!GetLengthProperty(cx, array, &n))
         return false;
 
     // steps i-k
     for (uint32_t i = 0; i < n; ++i) {