eu receboSubtype mark required in this context às(*). O que exatamente é a máscara de subtipo e por que está reclamando aqui?

main.adb

(*)Open_Route : Route(1..3) := (others => new Location(X=>1.0,Y=>1.0, id=>1));
--     Closed_Route : Route (Open_Route'First .. Open_Route'Last + 1);
--     P1 : Population (1..2);

Especificações do pacote Location.ads

    type Location is record
      Id : Positive;
      X : Float;
      Y : Float;
   end record;
   type Location_Acess is access all Location; 
   type Route is array (Positive range<>) of Location_Acess; 
   type Route_Acess is access all Route;
   type Population is array (Positive range<>) of Route_Acess;