Kernel.extend now raises a TypeError, when called on a frozen object

From a64dc1c80d4cee38e9c967979d2609895f38559a Mon Sep 17 00:00:00 2001
From: Jose Narvaez <goyox86@gmail.com>
Date: Sun, 18 Jul 2010 14:58:34 -0430
Subject: [PATCH 2/2] Kernel.extend now raises a TypeError, when called on a frozen object

---
 kernel/common/kernel.rb |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/common/kernel.rb b/kernel/common/kernel.rb
index fb897af..7bfcb22 100644
--- a/kernel/common/kernel.rb
+++ b/kernel/common/kernel.rb
@@ -380,6 +380,10 @@ module Kernel
   end
 
   def extend(*modules)
+    if self.frozen?
+      raise TypeError, "Cannot modify a frozen object"
+    end
+    
     modules.reverse_each do |mod|
       mod.__send__(:extend_object, self)
       mod.__send__(:extended, self)
-- 
1.7.0.3