diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
index 9c4d5fae26ede30f2cdaaffffac0f9df8c0a598a..2d88cb57e584a33b6486c5eba0ff1d2034df904e 100644
--- a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
+++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
@@ -5,9 +5,7 @@ def mattr_reader(*syms)
     options = syms.extract_options!
     syms.each do |sym|
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
-        unless defined? @@#{sym}
-          @@#{sym} = nil
-        end
+        @@#{sym} = nil unless defined? @@#{sym}
 
         def self.#{sym}
           @@#{sym}
@@ -28,10 +26,6 @@ def mattr_writer(*syms)
     options = syms.extract_options!
     syms.each do |sym|
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
-        unless defined? @@#{sym}
-          @@#{sym} = nil
-        end
-
         def self.#{sym}=(obj)
           @@#{sym} = obj
         end