association_valid?

# File activerecord/lib/active_record/autosave_association.rb, line 328
      def association_valid?(reflection, record, index=nil)
        return true if record.destroyed? || (reflection.options[:autosave] && record.marked_for_destruction?)

        validation_context = self.validation_context unless [:create, :update].include?(self.validation_context)
        unless valid = record.valid?(validation_context)
          if reflection.options[:autosave]
            indexed_attribute = !index.nil? && (reflection.options[:index_errors] || ActiveRecord::Base.index_nested_attribute_errors)

            record.errors.each do |attribute, message|
              if indexed_attribute
                attribute = "#{reflection.name}[#{index}].#{attribute}"
              else
                attribute = "#{reflection.name}.#{attribute}"
              end
              errors[attribute] << message
              errors[attribute].uniq!
            end

            record.errors.details.each_key do |attribute|
              if indexed_attribute
                reflection_attribute = "#{reflection.name}[#{index}].#{attribute}"
              else
                reflection_attribute = "#{reflection.name}.#{attribute}"
              end

              record.errors.details[attribute].each do |error|
                errors.details[reflection_attribute] << error
                errors.details[reflection_attribute].uniq!
              end
            end
          else
            errors.add(reflection.name)
          end
        end
        valid
      end