convert_to_id

# File activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb, line 45
        def convert_to_id(value)
          case value
          when Base
            value._read_attribute(primary_key(value))
          when Relation
            value.select(primary_key(value))
          else
            value
          end
        end