http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59294
Bug ID: 59294 Summary: template friend declaration 'hidden' by member of same name Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: stefan.schwarzer at ipm dot fraunhofer.de /* Dear experts, I would like to use the same identifier for a member function and a friend function of similar signature. Either declaring the friend or the member works fine, but if both (#ifdef PROBLEM true) are present, g++ starts yelling at me: */ template <class T> class Q; template <class T> const Q<T> conjugate(const Q<T> &); template<class T> struct Q { #define PROBLEM #ifdef PROBLEM const Q conjugate() { return *this; } #endif friend const Q<T> conjugate<T>(const Q<T> &); // PROBLEM // friend const Q conjugate<T>(const Q &); // -- equivalent // friend const Q conjugate<>(const Q &); // -- equivalent }; template <class T> const Q<T> conjugate(const Q<T> &) { return Q<T>(); } int main () { Q<int> q; #ifdef PROBLEM q.conjugate(); #endif conjugate(q); return 0; } /* $ g++ t.cc t.cc:17:20: error: ‘conjugate’ is neither function nor member function; cannot be declared friend friend const Q<T> conjugate<T>(const Q<T> &); ^ t.cc:17:20: error: expected ‘;’ at end of member declaration t.cc:17:29: error: expected unqualified-id before ‘<’ token friend const Q<T> conjugate<T>(const Q<T> &); Nothing I tried really helps: - the existence or not of the forward declaration does not help - my three feeble attempts of syntax variation (in comments) behave equivalently - using a qualified-id ::conjugate in the friend declaration only changes the error message Am I missing something basic or is this a compiler bug? (debian testing) $ g++ -v Using built-in specs. COLLECT_GCC=g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.8/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.8.2-1' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs --enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.8 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --with-system-zlib --disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64 --with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64 --with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --enable-objc-gc --enable-multiarch --with-arch-32=i586 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.8.2 (Debian 4.8.2-1) */