Discriminant & interface not implemented by full type

Discriminant & interface not implemented by full type

[Reto Buerki]

Hi everyone,

I have the following simple test application:

package Full_View is

   type Base_Type (Num : Integer) is tagged private;

   type Base_Interface is interface;

   type New_Type is new Base_Type (Num => 11) and
     Base_Interface with private;

private
   type Base_Type (Num : Integer) is tagged record
      My_Number : Integer := Num;
   end record;

   type New_Type is new Base_Type (Num => 11) and
     Base_Interface with null record;

end Full_View;

Trying to compile this with gnat gcc 4.3 in Debian/Lenny results in the
following error:
full_view.ads:7:09: interface "Base_Interface" not implemented by full
type (RM-2005 7.3 (7.3/2))

When removing the (Num => 11) discrimant initialization or the
Base_Interface interface from the New_Type type extension, the code
compiles fine.

Is this a compiler bug? Seems to me that the consistency check of the
partial and full view of a tagged type covering interfaces does not like
discriminants.

Thanks for your help.
- reto

Re: Discriminant & interface not implemented by full type

[Adam Beneschan]

On Mar 9, 10:21 am, Reto Buerki <r...@codelabs.ch> wrote:
> Hi everyone,
>
> I have the following simple test application:
>
> package Full_View is
>
>    type Base_Type (Num : Integer) is tagged private;
>
>    type Base_Interface is interface;
>
>    type New_Type is new Base_Type (Num => 11) and
>      Base_Interface with private;
>
> private
>    type Base_Type (Num : Integer) is tagged record
>       My_Number : Integer := Num;
>    end record;
>
>    type New_Type is new Base_Type (Num => 11) and
>      Base_Interface with null record;
>
> end Full_View;
>
> Trying to compile this with gnat gcc 4.3 in Debian/Lenny results in the
> following error:
> full_view.ads:7:09: interface "Base_Interface" not implemented by full
> type (RM-2005 7.3 (7.3/2))
>
> When removing the (Num => 11) discrimant initialization or the
> Base_Interface interface from the New_Type type extension, the code
> compiles fine.
>
> Is this a compiler bug? Seems to me that the consistency check of the
> partial and full view of a tagged type covering interfaces does not like
> discriminants.
>
> Thanks for your help.

Sure looks like a compiler bug to me.  The program definitely doesn't
violate the RM section paragraph that the error message refers to.

                             -- Adam

Re: Discriminant & interface not implemented by full type

[Per Sandberg]

Compiles fine with GNATPro 6.2.1
/Per

Reto Buerki wrote:
> Hi everyone,
> 
> I have the following simple test application:
> 
> package Full_View is
> 
>    type Base_Type (Num : Integer) is tagged private;
> 
>    type Base_Interface is interface;
> 
>    type New_Type is new Base_Type (Num => 11) and
>      Base_Interface with private;
> 
> private
>    type Base_Type (Num : Integer) is tagged record
>       My_Number : Integer := Num;
>    end record;
> 
>    type New_Type is new Base_Type (Num => 11) and
>      Base_Interface with null record;
> 
> end Full_View;
> 
> Trying to compile this with gnat gcc 4.3 in Debian/Lenny results in the
> following error:
> full_view.ads:7:09: interface "Base_Interface" not implemented by full
> type (RM-2005 7.3 (7.3/2))
> 
> When removing the (Num => 11) discrimant initialization or the
> Base_Interface interface from the New_Type type extension, the code
> compiles fine.
> 
> Is this a compiler bug? Seems to me that the consistency check of the
> partial and full view of a tagged type covering interfaces does not like
> discriminants.
> 
> Thanks for your help.
> - reto

Re: Discriminant & interface not implemented by full type

[Reto Buerki]

Per Sandberg wrote:
> Compiles fine with GNATPro 6.2.1
> /Per
> 
> Reto Buerki wrote:
>> Hi everyone,
>>
>> I have the following simple test application:
>>
>> package Full_View is
>>
>>    type Base_Type (Num : Integer) is tagged private;
>>
>>    type Base_Interface is interface;
>>
>>    type New_Type is new Base_Type (Num => 11) and
>>      Base_Interface with private;
>>
>> private
>>    type Base_Type (Num : Integer) is tagged record
>>       My_Number : Integer := Num;
>>    end record;
>>
>>    type New_Type is new Base_Type (Num => 11) and
>>      Base_Interface with null record;
>>
>> end Full_View;
>>
>> Trying to compile this with gnat gcc 4.3 in Debian/Lenny results in the
>> following error:
>> full_view.ads:7:09: interface "Base_Interface" not implemented by full
>> type (RM-2005 7.3 (7.3/2))
>>
>> When removing the (Num => 11) discrimant initialization or the
>> Base_Interface interface from the New_Type type extension, the code
>> compiles fine.
>>
>> Is this a compiler bug? Seems to me that the consistency check of the
>> partial and full view of a tagged type covering interfaces does not like
>> discriminants.

Adam, Per thanks for your replies!

I filed a GCC bug report [1].

- reto

[1] - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39441