diff --git a/js/src/jsopcode.c b/js/src/jsopcode.c
index 438edf82253a..2e5e74be3168 100644
--- a/js/src/jsopcode.c
+++ b/js/src/jsopcode.c
@@ -2579,8 +2579,11 @@ js_DecompileValueGenerator(JSContext *cx, intN spindex, jsval v,
             goto do_fallback;
 
         if (spindex != JSDVG_IGNORE_STACK) {
+            JS_ASSERT(spindex < 0);
             depth = (intN)script->depth;
-            JS_ASSERT(-depth <= spindex && spindex < 0);
+#if !JS_HAS_NO_SUCH_METHOD
+            JS_ASSERT(-depth <= spindex);
+#endif
             spindex -= depth;
 
             base = (jsval *) cx->stackPool.current->base;