2 files changed, 5 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog
index e7190036f3..beb5b0cf93 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Jan  8 11:43:05 2012  Narihiro Nakamura  <authornari@gmail.com>
+
+	* gc.c (slot_sweep): add a assertion instead of a debug print.
+
 Sun Jan  8 01:18:19 2012  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
 
 	* test/-ext-/old_thread_select/test_old_thread_select.rb:
diff --git a/gc.c b/gc.c
index d967fd8576..c2a1a7c6fd 100644
--- a/gc.c
+++ b/gc.c
@@ -2176,9 +2176,7 @@ slot_sweep(rb_objspace_t *objspace, struct heaps_slot *sweep_slot)
                     }
                     p->as.free.next = deferred_final_list;
                     deferred_final_list = p;
-                    if (BUILTIN_TYPE(p) != T_ZOMBIE) {
-                        fprintf(stderr, "NOT T_ZOMBIE!!\n");
-                    }
+                    assert(BUILTIN_TYPE(p) == T_ZOMBIE);
                     final_num++;
                 }
                 else {