title: Rails: How to dynamically create path for singular nested resource using polymorphic_path
body: <p>I have some singular nested resources and the entries for them looks like this:</p>
  
  <pre><code>resources :rocs, only: [:show] do
    resource :r1_response, :r2_response, :r3_response, :r4_response :r5_response do
      member do
        get :print
      end
    end
  end
  </code></pre>
  
  <p>Now I want to dynamically generate paths for my nested singular resources like below:</p>
  
  <pre><code>print_roc_r1_response_path
  print_roc_r2_response_path
  ...
  </code></pre>
  
  <p>I am trying to use <code>polymorphic_path</code> to generate above paths:</p>
  
  <pre><code>link_to "Print ROC", polymorphic_path([:print, @roc, controller.controller_name])
  </code></pre>
  
  <p>But it's giving error: <code>undefined method print_roc_r1_responses_path</code> cause <code>controller.controller_name</code> is <strong>plural</strong>. How do I fix it?</p>