Simple 4 lines hang code using Ravenscar. Its this a Gnat bug?

[Daniel <danielnorberto@gmail.com>]

Hello,
I found something strange using Ravenscar with Gnat. The code hangs without any explanation when i try to declare a task type...¡even if i dont use any variable of this type!!. If i quit the Ravenscar pragma it works well. This is the code:

--MAIN PROCEDURE
with tmr;
with ada.Text_IO; use ada.Text_IO;
procedure main is
begin
   put_line("Let's hang..");
end main;

--- TMR.ADS FILE
pragma Profile (Ravenscar);
package Tmr is
   task type K_Timer is
   end K_Timer;
end Tmr;

-- TMR.ADB FILE
package body Tmr is
   task body K_Timer  is
   begin
     null;
   end K_Timer;
end Tmr;


Im using GNAT GPL 2017 for windows. 
Thank you and best regards.