matz

git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@1065 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/class.c b/class.c
index 544652a4a..2eedb262d 100644
--- a/class.c
+++ b/class.c
@@ -241,6 +241,7 @@ rb_include_module(klass, module)
 		return;
 	    }
 	}
+	rb_frozen_class_p(klass);
 	RCLASS(klass)->super =
 	    include_class_new(module, RCLASS(klass)->super);
 	klass = RCLASS(klass)->super;