# File lib/mongoid/criteria.rb, line 224
    def merge(other)
      clone.tap do |crit|
        if other.is_a?(Criteria)
          crit.selector.update(other.selector)
          crit.options.update(other.options)
          crit.documents = other.documents
        else
          duped = other.dup
          crit.selector.update(duped.delete(:conditions) || {})
          crit.options.update(duped)
        end
      end
    end