GNAT CE 2019 bug: Predicate check not performed

[AdaMagica <christ-usch.grein@t-online.de>]

The problem is with GNAT CE 2019.
GNAT CE 2018 was correct.
------------------------------------------------
with Ada.Text_IO;
use  Ada.Text_IO;
with Ada.Assertions;
use  Ada.Assertions;

procedure Ass is

  pragma Assertion_Policy (Check);

  subtype String_5 is String with Dynamic_Predicate => String_5'First = 5;

  procedure P (X: String_5) is
  begin
    Put_Line ("P expects 5:" & X'First'Image);
  end P;

  procedure Q (X: String) is
  begin
    P (X);  -- Why no predicate check here?
  end Q;

  S: constant String := "Lady Ada";

begin

  begin
    Q (S);  -- prints 1, expected Assertion_Error
    Put_Line ("Problem Q: Assertion_Error not raised.");
  exception
    when Assertion_Error => Put_Line ("Q: Assertion_Error raised as expected.");
  end;

  begin
    P (S);  -- Assertion_Error raised here
    Put_Line ("Problem P: Assertion_Error not raised.");
  exception
    when Assertion_Error => Put_Line ("P: Assertion_Error raised as expected.");
  end;

end Ass;
---------------------
Result GNAT CE 2018
C:\Users\Grein\Documents\Christoph\Ada\Spielplatz\ausprobieren.exe
Q: Assertion_Error raised as expected.
P: Assertion_Error raised as expected.
[2020-04-18 19:33:34] process terminated successfully, elapsed time: 07.47s
Result GNAT CE 2019
C:\Users\Grein\Documents\Christoph\Ada\Spielplatz\ausprobieren.exe
P expects 5: 1
Problem Q: Assertion_Error not raised.
P: Assertion_Error raised as expected.
[2020-04-18 19:58:20] process terminated successfully, elapsed time: 04.25s