diff --git a/ChangeLog b/ChangeLog
index 825575d8a2..e7bc5a1806 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,11 @@
-Mon May 16 22:21:44 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Mon May 16 22:28:43 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* win32/win32.h, {bcc32,win32,wince}/Makefile.sub: moved rb_[ugp]id_t
 	  to get rid of redefinition warnings on mingw.
 
+	* class.c (rb_class_init_copy): singleton class is disallowed to copy,
+	  from its definition.  fixed: [ruby-talk:142749]
+
 Mon May 16 08:52:29 2005  Hirokazu Yamamoto  <ocean@m2.ccsnet.ne.jp>
 
 	* win32/win32.{h,c}: define rb_{p,g,u}id_t.
diff --git a/class.c b/class.c
index 8addef7612..b7f05dd4e5 100644
--- a/class.c
+++ b/class.c
@@ -92,6 +92,9 @@ rb_class_init_copy(clone, orig)
     if (RCLASS(clone)->super != 0) {
 	rb_raise(rb_eTypeError, "already initialized class");
     }
+    if (FL_TEST(orig, FL_SINGLETON)) {
+	rb_raise(rb_eTypeError, "can't copy singleton class");
+    }
     return rb_mod_init_copy(clone, orig);
 }