Rails 4 has_scope抛出未定义的方法错误

Question

对这个人有类似的问题：Rails 4 with has_scope: fails silently

但他的回答对我的情况没有帮助。我正在使用带有以下代码的has_scope gem：

<xsl:if test="$occupation contains('5','7','N','W','J','M')">

然后使用网址http://localhost:3000/inboxes/3?by_person=Meghan我收到此错误

#model
class Inbox < ActiveRecord::Base
  has_paper_trail
  has_many :requests
  belongs_to :match_rule
  scope :by_person, -> person { where(Request.where(inbox_id: params[:id]).person[:first_name] => person) }
end

#controller
class InboxesController < ApplicationController
  before_action :authorize
  before_action :set_inbox, only: [:show, :edit, :update, :destroy]
  before_filter :set_paper_trail_whodunnit
  has_scope :by_person

def show
  @requests = apply_scopes(Request.where(inbox_id: params[:id]).paginate(:page => params[:page], :per_page => 20))
end

private
  def set_inbox
    @inbox = Inbox.find(params[:id])
  end

这一行

undefined method `by_person' for #<Request::ActiveRecord_Relation:0x007fadf72a3148>

一旦我使用名字，我将继续进行所有其他事情的过滤。在这种情况下，我感谢任何帮助或指导！