private method doesn't work for singleton methods defined this way

activesupport/lib/active_support/callbacks.rb

@@ -131,8 +131,6 @@ def self.build(next_callback, user_callback, user_conditions, chain_config, filt
           end
         end
 
-        private
-
         def self.halting_and_conditional(next_callback, user_callback, user_conditions, halted_lambda, filter)
           lambda { |env|
             target = env.target
@@ -149,6 +147,7 @@ def self.halting_and_conditional(next_callback, user_callback, user_conditions,
             next_callback.call env
           }
         end
+        private_class_method :halting_and_conditional
 
         def self.halting(next_callback, user_callback, halted_lambda, filter)
           lambda { |env|
@@ -166,6 +165,7 @@ def self.halting(next_callback, user_callback, halted_lambda, filter)
             next_callback.call env
           }
         end
+        private_class_method :halting
 
         def self.conditional(next_callback, user_callback, user_conditions)
           lambda { |env|
@@ -178,6 +178,7 @@ def self.conditional(next_callback, user_callback, user_conditions)
             next_callback.call env
           }
         end
+        private_class_method :conditional
 
         def self.simple(next_callback, user_callback)
           lambda { |env|
@@ -185,6 +186,7 @@ def self.simple(next_callback, user_callback)
             next_callback.call env
           }
         end
+        private_class_method :simple
       end
 
       class After
@@ -208,8 +210,6 @@ def self.build(next_callback, user_callback, user_conditions, chain_config)
           end
         end
 
-        private
-
         def self.halting_and_conditional(next_callback, user_callback, user_conditions)
           lambda { |env|
             env = next_callback.call env
@@ -223,6 +223,7 @@ def self.halting_and_conditional(next_callback, user_callback, user_conditions)
             env
           }
         end
+        private_class_method :halting_and_conditional
 
         def self.halting(next_callback, user_callback)
           lambda { |env|
@@ -233,6 +234,7 @@ def self.halting(next_callback, user_callback)
             env
           }
         end
+        private_class_method :halting
 
         def self.conditional(next_callback, user_callback, user_conditions)
           lambda { |env|
@@ -246,6 +248,7 @@ def self.conditional(next_callback, user_callback, user_conditions)
             env
           }
         end
+        private_class_method :conditional
 
         def self.simple(next_callback, user_callback)
           lambda { |env|
@@ -254,6 +257,7 @@ def self.simple(next_callback, user_callback)
             env
           }
         end
+        private_class_method :simple
       end
 
       class Around
@@ -269,8 +273,6 @@ def self.build(next_callback, user_callback, user_conditions, chain_config)
           end
         end
 
-        private
-
         def self.halting_and_conditional(next_callback, user_callback, user_conditions)
           lambda { |env|
             target = env.target
@@ -288,6 +290,7 @@ def self.halting_and_conditional(next_callback, user_callback, user_conditions)
             end
           }
         end
+        private_class_method :halting_and_conditional
 
         def self.halting(next_callback, user_callback)
           lambda { |env|
@@ -305,6 +308,7 @@ def self.halting(next_callback, user_callback)
             end
           }
         end
+        private_class_method :halting
 
         def self.conditional(next_callback, user_callback, user_conditions)
           lambda { |env|
@@ -322,6 +326,7 @@ def self.conditional(next_callback, user_callback, user_conditions)
             end
           }
         end
+        private_class_method :conditional
 
         def self.simple(next_callback, user_callback)
           lambda { |env|
@@ -332,6 +337,7 @@ def self.simple(next_callback, user_callback)
             env
           }
         end
+        private_class_method :simple
       end
     end