--- old/src/hotspot/share/gc/shenandoah/shenandoahMarkCompact.cpp	2020-01-24 15:21:07.388527444 +0100
+++ new/src/hotspot/share/gc/shenandoah/shenandoahMarkCompact.cpp	2020-01-24 15:21:07.140523275 +0100
@@ -297,7 +297,7 @@
   void do_object(oop p) {
     assert(_from_region != NULL, "must set before work");
     assert(_heap->complete_marking_context()->is_marked(p), "must be marked");
-    assert(!_heap->complete_marking_context()->allocated_after_mark_start(p), "must be truly marked");
+    assert(!_heap->complete_marking_context()->allocated_after_mark_start(cast_from_oop<HeapWord*>(p)), "must be truly marked");
 
     size_t obj_size = p->size();
     if (_compact_point + obj_size > _to_region->end()) {