type_conflict!

# File actionpack/lib/action_controller/request.rb, line 722
      def type_conflict!(klass, value)
        raise TypeError, "Conflicting types for parameter containers. Expected an instance of #{klass} but found an instance of #{value.class}. This can be caused by colliding Array and Hash parameters like qs[]=value&qs[key]=value. (The parameters received were #{value.inspect}.)"
      end