type_cast_pluck_values

# File activerecord/lib/active_record/relation/calculations.rb, line 427
      def type_cast_pluck_values(result, columns)
        cast_types = if result.columns.size != columns.size
          klass.attribute_types
        else
          join_dependencies = nil
          columns.map.with_index do |column, i|
            column.try(:type_caster) ||
              klass.attribute_types.fetch(name = result.columns[i]) do
                join_dependencies ||= build_join_dependencies
                lookup_cast_type_from_join_dependencies(name, join_dependencies) ||
                  result.column_types[name] || Type.default_value
              end
          end
        end
        result.cast_values(cast_types)
      end