Re: How many Ada compiler bugs are here?

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

On 13.01.12 12:39, Dmitry A. Kazakov wrote:
> On 13 Jan 2012 10:38:04 GMT, georg bauhaus wrote:
> 
>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
>>
>>>
>>> package P is
>>>    type T (<>) is private;
>>> private
>>>    type T is new Integer;
>>> end P;
>>>
>>  
>> package P.Dummies is
>>    Meaningless_Dummy : constant T;
>>    Raising_Dummy : constant T;
>> private
>>    ...
>> End P.Dummies;
> 
> Which of course defies the very idea of requiring T initialized. If there
> exist some Meaningless_Dummy constant, then that could serve as an initial
> value for T.

I'd drop Meaningless_Dummy, then, and declare only the dummy
that raises an exception:

package P is
   type T (<>) is private;
private
   type T is new Integer;
   function Raises_Assertion_Error return T;
end P;

package P.Dummies is
   Raising_Dummy : constant T;
private
   Raising_Dummy : constant T := Raises_Assertion_Error;
end P.Dummies;

-- or make Raising_Dummy a constructing function that raises,
-- so that raising happens where Raising_Dummy is written.

with Ada.Assertions;
package body P is
   function Raises_Assertion_Error return T is
      use Ada.Assertions;
   begin
      raise Assertion_Error with "FIXME";
      return Raises_Assertion_Error;
   end Raises_Assertion_Error;
end P;

Is this about statically ascertaining that a meaningful initial value
has been stored in an object of type T, where "meaningful" is a statically
known consequence of using some construction feature of non-Ada, or
not-yet-Ada?