[Bug c++/35727] New: Nested class of specialized template class bug

[Bug c++/35727] New: Nested class of specialized template class bug

[philippe at fornux dot com]

** I am trying to compile a program that looks like the following but the
compiler cannot recognize which class the nested class belongs to:

#include <iostream>


using namespace std;


template <typename T>
        struct A
        {
                class B;
                friend class B;
        };


template <>
        struct A<void>
        {
                class B;
                friend class B;
        };


template <typename T>
        struct A<T>::B
        {
                B() 
        {
            cout << __PRETTY_FUNCTION__ << endl;
        }
        };


int main()
{
    A<void>::B b;
}


** Reports:
nesttempspecbug.cpp: In function `int main()':
nesttempspecbug.cpp:35: error: aggregate `A<void>::B b' has incomplete type and
cannot be defined


-- 
           Summary: Nested class of specialized template class bug
           Product: gcc
           Version: 3.4.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: philippe at fornux dot com
 GCC build triplet: gcc version 3.4.5 (mingw special)
  GCC host triplet: Windows XP
GCC target triplet: MinGW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35727

[Bug c++/35727] Nested class of specialized template class bug

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2008-03-28 00:25 -------
This error message is correct as you specialized A<void> but you also need to
specialize the nested class as the non specialized version of the nested
function will not be used.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35727

[Bug c++/35727] Nested class of specialized template class bug

[philippe at fornux dot com]

------- Comment #2 from philippe at fornux dot com  2008-03-28 05:20 -------
** Then if I add the following:

template <>
        struct A<void>::B
        {
                B() 
                {
                        cout << __PRETTY_FUNCTION__ << endl;
                }
        };


** I get:

nesttempspecbug.cpp:35: error: explicit specialization of non-template
`A<void>::B'
nesttempspecbug.cpp:35: error: explicit specialization of non-template
`A<void>::B'


-- 

philippe at fornux dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35727

[Bug c++/35727] Nested class of specialized template class bug

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2008-12-29 04:06 -------
You just want:
struct A<void>::B
{
        B() 
        {
                cout << __PRETTY_FUNCTION__ << endl;
        }
};

Since you already specialized A<void>, you don't need to specialize 
A<void>::B.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35727