1 files changed, 5 insertions, 0 deletions

diff --git a/src/alloc.c b/src/alloc.c
index e6edea42c95..07775391bfb 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1460,6 +1460,11 @@ mark_object (objptr)
 {
   register Lisp_Object obj;
 
+#ifdef DEBUG_MOLE
+  if (*(int *) ((char *)__builtin_frame_address (0) - 16) == 0)
+    abort ();
+#endif
+
   obj = *objptr;
   XUNMARK (obj);