Restore PushStackTraceAndDie for the case where we lookup starting with null

src/lookup.cc

Index: src/lookup.cc
diff --git a/src/lookup.cc b/src/lookup.cc
index 929b022ed5faa5b14ff5b8d536a60e21d612d101..36eba03f9f459e52932ab6721d02b2fb7a5bc449 100644
--- a/src/lookup.cc
+++ b/src/lookup.cc
@@ -63,7 +63,10 @@ Handle<JSReceiver> LookupIterator::GetRoot(Handle<Object> receiver,
                                            Isolate* isolate) {
   if (receiver->IsJSReceiver()) return Handle<JSReceiver>::cast(receiver);
   auto root = handle(receiver->GetRootMap(isolate)->prototype(), isolate);
-  CHECK(!root->IsNull());
+  if (root->IsNull()) {
+    unsigned int magic = 0xbbbbbbbb;
+    isolate->PushStackTraceAndDie(magic, NULL, NULL, magic);

[Jakob Kummerow, 2015/03/25 12:42:43]

How 'bout passing *receiver as the second argument?

[Toon Verwaest, 2015/03/25 12:44:40]

Acknowledged.

+  }
   return Handle<JSReceiver>::cast(root);
 }