Version 5.0.71.44 (cherry-pick)

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 67a59638318844e977ebd41dc875b87bba26e457..a60b2d5428862053378864cb9b92ffee547e0bc5 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -13715,7 +13715,9 @@ void JSFunction::CalculateInstanceSizeForDerivedClass(
   for (PrototypeIterator iter(isolate, this,
                               PrototypeIterator::START_AT_RECEIVER);
        !iter.IsAtEnd(); iter.Advance()) {
-    JSFunction* func = iter.GetCurrent<JSFunction>();
+    JSReceiver* current = iter.GetCurrent<JSReceiver>();
+    if (!current->IsJSFunction()) break;
+    JSFunction* func = JSFunction::cast(current);
     SharedFunctionInfo* shared = func->shared();
     expected_nof_properties += shared->expected_nof_properties();
     if (!IsSubclassConstructor(shared->kind())) {