Rails:活动记录销毁时出现未初始化常量错误

尝试销毁活动记录实例时遇到问题。

它涉及以下AR

class Client < ActiveRecord::Base
    has_many :phone_numbers, :dependent => :destroy
    has_many :email_addresses, :dependent => :destroy
    has_many :user_clients , :dependent => :destroy
    has_many :users, :through => :user_clients 
end

class UserClient  < ActiveRecord::Base
belongs_to :user
belongs_to :client , :dependent => :destroy
has_many :instructions, :dependent => :destroy
end

@dead_man = Client.find(params[:id])
@dead_man.destroy => uninitialized constant UserClient::Instruction

我真的不知道这个错误是从哪里来的。非常感谢任何帮助!