association_valid?

# File activerecord/lib/active_record/autosave_association.rb, line 371
      def association_valid?(association, record)
        return true if record.destroyed? || (association.options[:autosave] && record.marked_for_destruction?)

        context = validation_context if custom_validation_context?
        return true if record.valid?(context)

        if context || record.changed_for_autosave?
          associated_errors = record.errors.objects
        else
          # If there are existing invalid records in the DB, we should still be able to reference them.
          # Unless a record (no matter where in the association chain) is invalid and is being changed.
          associated_errors = record.errors.objects.select { |error| error.is_a?(Associations::NestedError) }
        end

        if association.options[:autosave]
          return if equal?(record)

          associated_errors.each { |error|
            errors.objects.append(
              Associations::NestedError.new(association, error)
            )
          }
        elsif associated_errors.any?
          errors.add(association.reflection.name)
        end

        errors.any?
      end