Bug 779841 - Escape inline cache if invalidated by the lookup. r=dvander

js/src/ion/IonCaches.cpp

@@ -329,6 +329,10 @@ js::ion::GetPropertyCache(JSContext *cx, size_t cacheIndex, HandleObject obj, Mu
 
         topScript->invalidatedIdempotentCache = true;
 
+        // Do not re-invalidate if the lookup already caused invalidation.
+        if (!topScript->hasIonScript())
+            return true;
+
         return Invalidate(cx, topScript);
     }
 

js/src/jit-test/tests/ion/bug779841.js

@@ -0,0 +1,7 @@
+// |jit-test| error: TypeError
+
+function outer2() {
+    "use strict";
+    new (function () {}).arguments
+}
+outer2();