construct_relation_for_association_calculations

# File activerecord/lib/active_record/relation/finder_methods.rb, line 217
    def construct_relation_for_association_calculations
      including = (eager_load_values + includes_values).uniq
      join_dependency = ActiveRecord::Associations::JoinDependency.new(@klass, including, arel.froms.first)
      relation = except(:includes, :eager_load, :preload)
      apply_join_dependency(relation, join_dependency)
    end