--- a/js/src/jit/VMFunctions.cpp
+++ b/js/src/jit/VMFunctions.cpp
@@ -1784,19 +1784,19 @@ bool EqualStringsHelperPure(JSString* st
   if (!str2Linear) {
     return false;
   }
 
   return EqualChars(&str1->asLinear(), str2Linear);
 }
 
 static bool MaybeTypedArrayIndexString(jsid id) {
-  MOZ_ASSERT(JSID_IS_ATOM(id) || JSID_IS_SYMBOL(id));
-
-  if (MOZ_LIKELY(JSID_IS_ATOM(id))) {
+  MOZ_ASSERT(id.isAtom() || JSID_IS_SYMBOL(id));
+
+  if (MOZ_LIKELY(id.isAtom())) {
     JSAtom* str = JSID_TO_ATOM(id);
     if (str->length() > 0) {
       // Only check the first character because we want this function to be
       // fast.
       return CanStartTypedArrayIndex(str->latin1OrTwoByteChar(0));
     }
   }
   return false;
@@ -1806,17 +1806,17 @@ static MOZ_ALWAYS_INLINE bool GetNativeD
                                                         NativeObject* obj,
                                                         jsid id, Value* vp) {
   // Fast path used by megamorphic IC stubs. Unlike our other property
   // lookup paths, this is optimized to be as fast as possible for simple
   // data property lookups.
 
   AutoUnsafeCallWithABI unsafe;
 
-  MOZ_ASSERT(JSID_IS_ATOM(id) || JSID_IS_SYMBOL(id));
+  MOZ_ASSERT(id.isAtom() || JSID_IS_SYMBOL(id));
 
   while (true) {
     if (Shape* shape = obj->lastProperty()->search(cx, id)) {
       if (!shape->isDataProperty()) {
         return false;
       }
 
       *vp = obj->getSlot(shape->slot());