<ActiveRecord::Associations::CollectionProxy [#<Submission id: nil,user_id: nil,card_id: 7,created_at: nil,updated_at: nil,text: "">]>

@ card.submissions.any？返回true.

@ card.submissions.count返回0.

我想要实现的是：

if @card.submissions.any?
  render @card.submissions
end