#include <iostream>
using namespace std;
template <typename T> class C1 {
public:
T V;
C1(T v) : V(v) {};
class nested {
public:
T W;
nested(T w) : W(w) {};
};
};
// This works well
template <typename T>
T f1 ( C1<T>& c) { return c.V; }
// the problem is HERE
template <typename T>
T f2 ( typename C1<T>::nested& c) { return c.W; }
// This is correct with gcc 3.3.2 20031022
// This is incorrect with gcc 3.4.2 20041017
// This is incorrect with gcc 3.4.3 20041226
// This is incorrect with gcc4 4.0.0 20041228
// Error :
// nestedFriendTemplateFunction.cc:44: error: no matching function for call to
`f2(C1<float>::nested&)'
// Need EXPLICITE instantiation ==> GCC BUG !!!
// float f2 (C1<float>::nested& c) { return c.W; }
int main() {
C1<int> c(123);
cout<<f1(c)<<endl;
C1<float>::nested n(3.5);
cout<<n.W<<endl;
cout<<f2(n)<<endl; // CANNOT FIND THE CORRECT CODE FOR THIS
}
So, starting from version 3.4.2 it is no more possible to use a template
function that refers to a nested class of a template class.
g++ versions :
Reading specs from /usr/lib/gcc/i386-redhat-linux/3.4.3/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--disable-checking --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-java-awt=gtk --host=i386-redhat-linux
Thread model: posix
gcc version 3.4.3 20041226 (Red Hat 3.4.3-11)
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --with-gxx-include-dir=/usr/include/c++/3.4.3
--enable-languages=c,c++,java,f95 --enable-java-awt=gtk --host=i386-redhat-linux
Thread model: posix
gcc version 4.0.0 20041228 (Red Hat 4.0.0-0.17)
--
Summary: No more possible to have a template function that uses a
nested class of a template class
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jean-pierre dot chevallet at imag dot fr
CC: gcc-bugs at gcc dot gnu dot org
GCC host triplet: i386-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19288
