diff --git a/ChangeLog b/ChangeLog
index 45965ed728..20071992cc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 10 09:29:12 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (rb_clear_cache_for_undef): clear entries for included
+	  module.  fixed: [ruby-core:08180]
+
 Sun Jul  9 18:06:47 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/mkmf.rb (try_constant): fix for value 1 at cross compiling.
diff --git a/eval.c b/eval.c
index f099654d1c..9a909557e8 100644
--- a/eval.c
+++ b/eval.c
@@ -366,7 +366,8 @@ rb_clear_cache_for_undef(klass, id)
     if (!ruby_running) return;
     ent = cache; end = ent + CACHE_SIZE;
     while (ent < end) {
-	if (ent->origin == klass && ent->mid == id) {
+	if (ent->mid == id &&
+	    RCLASS(ent->origin)->m_tbl == RCLASS(klass)->m_tbl) {
 	    ent->mid = 0;
 	}
 	ent++;