Assume that ReportFailedAccessCheck always schedules an exception.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 433dda7d6f98daa1aac991c04413c4d3d4501bc8..2bc2299ed79ef09c531ebc7d86a79188e0cb504c 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -1011,7 +1011,8 @@ MaybeHandle<Object> JSObject::GetPropertyWithFailedAccessCheck(
 
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(it->isolate(), Object);
-  return it->factory()->undefined_value();
+  UNREACHABLE();
+  return MaybeHandle<Object>();
 }
 
 
@@ -1030,7 +1031,8 @@ Maybe<PropertyAttributes> JSObject::GetPropertyAttributesWithFailedAccessCheck(
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(it->isolate(),
                                       Nothing<PropertyAttributes>());
-  return Just(ABSENT);
+  UNREACHABLE();
+  return Nothing<PropertyAttributes>();
 }
 
 
@@ -1059,8 +1061,6 @@ Maybe<bool> JSObject::SetPropertyWithFailedAccessCheck(
   it->isolate()->ReportFailedAccessCheck(checked);
   RETURN_VALUE_IF_SCHEDULED_EXCEPTION(it->isolate(), Nothing<bool>());
   UNREACHABLE();
-  it->isolate()->Throw(
-      *it->isolate()->factory()->NewTypeError(MessageTemplate::kNoAccess));
   return Nothing<bool>();
 }
 
@@ -4792,7 +4792,7 @@ MaybeHandle<Object> JSObject::DefineOwnPropertyIgnoreAttributes(
         if (!it->HasAccess()) {
           it->isolate()->ReportFailedAccessCheck(it->GetHolder<JSObject>());
           RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(it->isolate(), Object);
-          return value;
+          UNREACHABLE();
         }
         break;
 
@@ -5821,7 +5821,7 @@ MaybeHandle<Object> JSReceiver::DeleteProperty(LookupIterator* it,
         if (it->HasAccess()) break;
         isolate->ReportFailedAccessCheck(it->GetHolder<JSObject>());
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-        return it->factory()->false_value();
+        UNREACHABLE();
       case LookupIterator::INTERCEPTOR: {
         MaybeHandle<Object> maybe_result =
             JSObject::DeletePropertyWithInterceptor(it);
@@ -6782,8 +6782,6 @@ Maybe<bool> JSObject::PreventExtensions(Handle<JSObject> object,
     isolate->ReportFailedAccessCheck(object);
     RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate, Nothing<bool>());
     UNREACHABLE();
-    RETURN_FAILURE(isolate, should_throw,
-                   NewTypeError(MessageTemplate::kNoAccess));
   }
 
   if (object->IsJSGlobalProxy()) {
@@ -6883,8 +6881,6 @@ Maybe<bool> JSObject::PreventExtensionsWithTransition(
     isolate->ReportFailedAccessCheck(object);
     RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate, Nothing<bool>());
     UNREACHABLE();
-    RETURN_FAILURE(isolate, should_throw,
-                   NewTypeError(MessageTemplate::kNoAccess));
   }
 
   if (object->IsJSGlobalProxy()) {
@@ -7778,6 +7774,7 @@ MaybeHandle<FixedArray> JSReceiver::GetKeys(Handle<JSReceiver> object,
       if (iter.IsAtEnd(PrototypeIterator::END_AT_NON_HIDDEN)) {
         isolate->ReportFailedAccessCheck(current);
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, FixedArray);
+        UNREACHABLE();
       }
       break;
     }
@@ -7890,7 +7887,7 @@ MaybeHandle<Object> JSObject::DefineAccessor(LookupIterator* it,
     if (!it->HasAccess()) {
       isolate->ReportFailedAccessCheck(it->GetHolder<JSObject>());
       RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-      return isolate->factory()->undefined_value();
+      UNREACHABLE();
     }
     it->Next();
   }
@@ -7955,7 +7952,7 @@ MaybeHandle<Object> JSObject::SetAccessor(Handle<JSObject> object,
     if (!it.HasAccess()) {
       isolate->ReportFailedAccessCheck(object);
       RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-      return it.factory()->undefined_value();
+      UNREACHABLE();
     }
     it.Next();
   }
@@ -8002,7 +7999,7 @@ MaybeHandle<Object> JSObject::GetAccessor(Handle<JSObject> object,
         if (it.HasAccess()) continue;
         isolate->ReportFailedAccessCheck(it.GetHolder<JSObject>());
         RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-        return isolate->factory()->undefined_value();
+        UNREACHABLE();
 
       case LookupIterator::JSPROXY:
         return isolate->factory()->undefined_value();