c++/10694: [3.3/3.4 regression] Befriending a function in a class that is only forward-declared

[bangerth at dealii dot org]

>Number:         10694
>Category:       c++
>Synopsis:       [3.3/3.4 regression] Befriending a function in a class that is only forward-declared
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri May 09 01:16:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Wolfgang Bangerth
>Release:        unknown-1.0
>Organization:
>Environment:
3.3 and present mainline
>Description:
Extracted from PR 7818 (but unrelated to the original
cause of that PR):

This used to work until 3.2.3, but fails in 3.3 and mainline:
--------------------------
template <class T> struct Y;
    
template <class S> class X {
    template <class T> friend void Y<T>::member();
};
    
template <class T> struct Y {
    void member() {
      X<int>();
    }
};
    
template class Y<int>;
-------------------------------
g/x> /home/bangerth/bin/gcc-3.2.3-pre/bin/c++ x.cc -W -Wall -c


g/x> /home/bangerth/bin/gcc-3.3-pre/bin/c++ -c x.cc -W -Wall
x.cc: In instantiation of `X<int>':
x.cc:9:   instantiated from `void Y<T>::member() [with T = int]'
x.cc:13:   instantiated from here
x.cc:4: error: prototype for `template<class T> void Y::member()' does not
   match any in class `Y<T>'
x.cc:8: error: candidate is: void Y<T>::member()


g/x> /home/bangerth/bin/gcc-3.4-pre/bin/c++ -c x.cc -W -Wall
x.cc: In instantiation of `X<int>':
x.cc:9:   instantiated from `void Y<T>::member() [with T = int]'
x.cc:13:   instantiated from here
x.cc:4: error: prototype for `template<class T> void Y::member()' does not
   match any in class `Y<T>'
x.cc:8: error: candidate is: void Y<T>::member()
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: