TypeError in MainController#results

no implicit conversion of nil into String

Extracted source (around line #263):
261
262
263
264
265
266
          
else
results = results.where(city_id: 0)
@location_display = params[:city] + ", " + @location_display
@location_string = params[:city] + ", " + @location_string
end
end

Rails.root: /home/webapp/findhorsesforsale.com

Application Trace | Framework Trace | Full Trace
app/controllers/main_controller.rb:263:in `+'
app/controllers/main_controller.rb:263:in `results'

Request

Parameters:

{"country_code"=>"US",
 "state_code"=>"HI",
 "city"=>"K%C4%ABhei"}

Response

Headers:

None