diff --git a/ChangeLog b/ChangeLog
index 1c9c20a1b5..548e0a24f6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,7 @@
-Tue Sep 29 13:37:50 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Tue Sep 29 13:48:58 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm_method.c (rb_method_definition_eq): non-null definition is
+	  not equal to null definition.
 
 	* vm_method.c (rb_add_method_def): nothing to do if old method had
 	  same definition.  [ruby-dev:39397]
diff --git a/vm_method.c b/vm_method.c
index 434e8424cc..808c64c47e 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -799,9 +799,8 @@ rb_method_entry_eq(const rb_method_entry_t *m1, const rb_method_entry_t *m2)
 static int
 rb_method_definition_eq(const rb_method_definition_t *d1, const rb_method_definition_t *d2)
 {
-    if (!d1) {
-	return !d2;
-    }
+    if (d1 == d2) return 1;
+    if (!d1 || !d2) return 0;
     if (d1->type != d2->type) {
 	return 0;
     }