From f6bedc960dfbd2a5262d65c69fb51789b060643e Mon Sep 17 00:00:00 2001
From: Grant Hutchins <nertzy@gmail.com>
Date: Wed, 27 Jun 2012 20:09:30 -0400
Subject: [PATCH] Speed up Hash#transform_keys using Hash#each_key

See https://gist.github.com/3007749 for justification
---
 activesupport/lib/active_support/core_ext/hash/keys.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index 8e728691c675..e753e36124c4 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -7,7 +7,7 @@ class Hash
   #  # => { "NAME" => "Rob", "AGE" => "28" }
   def transform_keys
     result = {}
-    keys.each do |key|
+    each_key do |key|
       result[yield(key)] = self[key]
     end
     result