diff --git a/ChangeLog b/ChangeLog
index 8dc4e5b36f..7849662b2a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Thu Feb 12 03:28:05 2015  Eric Wong  <e@80x24.org>
+
+	* lib/set.rb (initialize): internal hash defaults to false
+
+	* lib/set.rb (include?): use Hash#[] for optimized dispatch.
+	  Patch by Ismael Abreu <ismaelga@gmail.com>
+	  [ruby-core:67664] [Misc #10754]
+
 Wed Feb 11 11:09:52 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/digest/digest_conf.rb (digest_conf): check for CommonDigest.
diff --git a/lib/set.rb b/lib/set.rb
index f00cfac0c5..a3f185538f 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -78,7 +78,7 @@ class Set
   # If a block is given, the elements of enum are preprocessed by the
   # given block.
   def initialize(enum = nil, &block) # :yields: o
-    @hash ||= Hash.new
+    @hash ||= Hash.new(false)
 
     enum.nil? and return
 
@@ -209,7 +209,7 @@ class Set
 
   # Returns true if the set contains the given object.
   def include?(o)
-    @hash.include?(o)
+    @hash[o]
   end
   alias member? include?