create_extension_modules

# File activerecord/lib/active_record/associations.rb, line 1798
        def create_extension_modules(association_id, block_extension, extensions)
          if block_extension
            extension_module_name = "#{self.to_s.demodulize}#{association_id.to_s.camelize}AssociationExtension"

            silence_warnings do
              self.parent.const_set(extension_module_name, Module.new(&block_extension))
            end
            Array(extensions).push("#{self.parent}::#{extension_module_name}".constantize)
          else
            Array(extensions)
          end
        end