3 files changed, 12 insertions, 3 deletions
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index 78e6f67a47..139de16326 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -4,6 +4,7 @@ module ActiveModel
     class AcceptanceValidator < EachValidator # :nodoc:
       def initialize(options)
         super({ allow_nil: true, accept: "1" }.merge!(options))
+        setup!(options[:class])
       end
 
       def validate_each(record, attribute, value)
@@ -12,7 +13,8 @@ module ActiveModel
         end
       end
 
-      def setup(klass)
+      private
+      def setup!(klass)
         attr_readers = attributes.reject { |name| klass.attribute_method?(name) }
         attr_writers = attributes.reject { |name| klass.attribute_method?("#{name}=") }
         klass.send(:attr_reader, *attr_readers)
diff --git a/activemodel/lib/active_model/validations/confirmation.rb b/activemodel/lib/active_model/validations/confirmation.rb
index 1d85378892..b0542661af 100644
--- a/activemodel/lib/active_model/validations/confirmation.rb
+++ b/activemodel/lib/active_model/validations/confirmation.rb
@@ -2,6 +2,11 @@ module ActiveModel
 
   module Validations
     class ConfirmationValidator < EachValidator # :nodoc:
+      def initialize(options)
+        super
+        setup!(options[:class])
+      end
+
       def validate_each(record, attribute, value)
         if (confirmed = record.send("#{attribute}_confirmation")) && (value != confirmed)
           human_attribute_name = record.class.human_attribute_name(attribute)
@@ -9,7 +14,8 @@ module ActiveModel
         end
       end
 
-      def setup(klass)
+      private
+      def setup!(klass)
         klass.send(:attr_reader, *attributes.map do |attribute|
           :"#{attribute}_confirmation" unless klass.method_defined?(:"#{attribute}_confirmation")
         end.compact)
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
index 2ae335d0f4..16bd6670d1 100644
--- a/activemodel/lib/active_model/validations/with.rb
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -83,9 +83,10 @@ module ActiveModel
       #   end
       def validates_with(*args, &block)
         options = args.extract_options!
+        options[:class] = self
+
         args.each do |klass|
           validator = klass.new(options, &block)
-          validator.setup(self) if validator.respond_to?(:setup)
 
           if validator.respond_to?(:attributes) && !validator.attributes.empty?
             validator.attributes.each do |attribute|