使用Rails 3.2，這段代碼有什么問題？@reviews = @user.reviews.includes(:user, :reviewable).where('reviewable_type = ? AND reviewable.shop_type = ?', 'Shop', 'cafe')它引發此錯誤：無法急切加載多態關聯：可審查如果我刪除該reviewable.shop_type = ?條件，它將起作用。如何根據reviewable_type和過濾reviewable.shop_type（實際上是shop.shop_type）？