What's wrong with this class temlate's typedef?

What's wrong with this class temlate's typedef?

[Rob]

Hi,

The following code snippet is a stripped down version of what I use in my code.
Last time I compiled this code is several years ago......I tried to compile it again
today with GCC 4.3.0 (20080428), but now I get an error message:

--------------------------------------------------------
template <typename T = double, unsigned int d = 3> class A { };

template <typename T = double> class B : public A<T, 4> {
    typedef A<T, 3> A;
};

int main () { B<double> *object; };
--------------------------------------------------------


Error message:
   4: error: declaration of ‘typedef class A<T, 3u> B<T>::A’
   1: error: changes meaning of ‘A’ from ‘class A<T, 3u>’

Here, I could use class "A" as a substitute for "A<T,3>" only within the class B.
That used to work in the past. Is there a way to get this compiled again without
having to change all the class names in the typedef?

Thank you.

Rob.

Re: What's wrong with this class temlate's typedef?

[Lawrence Crowl]

On 7/22/08, Rob <spamrefuse@yahoo.com> wrote:
> The following code snippet is a stripped down version of what I use
> in my code.  Last time I compiled this code is several years ago......
> I tried to compile it again today with GCC 4.3.0 (20080428), but
> now I get an error message:
>
> --------------------------------------------------------
> template <typename T = double, unsigned int d = 3> class A { };
>
> template <typename T = double> class B : public A<T, 4> {
>    typedef A<T, 3> A;
> };
>
> int main () { B<double> *object; };
> --------------------------------------------------------
>
> Error message:
>   4: error: declaration of 'typedef class A<T, 3u> B<T>::A'
>   1: error: changes meaning of 'A' from 'class A<T, 3u>'
>
> Here, I could use class "A" as a substitute for "A<T,3>" only within
> the class B.  That used to work in the past.

The code has never been legal, but has worked because (1) the
compiler did not check and (2) the compiler processed declarations
in such a way that it did what you wanted.

> Is there a way to get this compiled again without having to change
> all the class names in the typedef?

Yes, qualify the definition of the typedef.

  typedef ::A<T, 3> A;

-- 
Lawrence Crowl