routes.md

resources :users do
  get 'hoge' # 1
  get ':id/hoge' # 2
end

resources :users do
  collection do
    get ':id/hoge' # 3
    get ':id/hoge' => 'users#hoge' # 4
  end
end

結果

1. GET    /users/:user_id/login(.:format)     users#login
2. GET    /users/:user_id/:id/login(.:format) users#login
3. GET    /users/:id/login(.:format)          users/:id#login
4. GET    /users/:id/login(.:format)          users#login

:user_id

みたいに渡すのをなんとなくをやめたかったのです。