Don't do remove_possible_method when delegate is used. Two reasons: 1) warnings should be shown, and fixed at the source and 2) the code is slow. Fixes #1937.

actionpack/lib/abstract_controller/layouts.rb

@@ -139,7 +139,7 @@ module AbstractController
   #
   #   end
   #
-  # This will assign "weblog_standard" as the WeblogController's layout for all actions except for the +rss+ action, which will 
+  # This will assign "weblog_standard" as the WeblogController's layout for all actions except for the +rss+ action, which will
   # be rendered directly, without wrapping a layout around the rendered view.
   #
   # Both the <tt>:only</tt> and <tt>:except</tt> condition can accept an arbitrary number of method references, so
@@ -167,6 +167,7 @@ module AbstractController
 
     included do
       class_attribute :_layout_conditions
+      remove_possible_method :_layout_conditions
       delegate :_layout_conditions, :to => :'self.class'
       self._layout_conditions = {}
       _write_layout_method

activesupport/lib/active_support/core_ext/module/delegation.rb

@@ -127,10 +127,6 @@ class Module
         end
 
       module_eval(<<-EOS, file, line - 5)
-        if instance_methods(false).map(&:to_s).include?("#{prefix}#{method}")
-          remove_possible_method("#{prefix}#{method}")
-        end
-
         def #{prefix}#{method}(*args, &block)               # def customer_name(*args, &block)
           #{to}.__send__(#{method.inspect}, *args, &block)  #   client.__send__(:name, *args, &block)
         rescue NoMethodError                                # rescue NoMethodError