--- old/src/hotspot/share/gc/z/zCollectedHeap.cpp	2019-03-28 22:45:27.249307423 +0100
+++ new/src/hotspot/share/gc/z/zCollectedHeap.cpp	2019-03-28 22:45:27.027300278 +0100
@@ -110,10 +110,6 @@
   return is_in_reserved(p) && _heap.is_in((uintptr_t)p);
 }
 
-bool ZCollectedHeap::is_in_closed_subset(const void* p) const {
-  return is_in(p);
-}
-
 HeapWord* ZCollectedHeap::allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) {
   const size_t size_in_bytes = ZUtils::words_to_bytes(align_object_size(requested_size));
   const uintptr_t addr = _heap.alloc_tlab(size_in_bytes);