This piece of code template<typename T> struct MemberGet{ static constexpr auto assign_operator = static_cast<T & (T::*)(const T &)>(&T::operator=); }; fails with this error: error: declaration of ‘constexpr const auto MemberGet<fpga::FPGAFilter>::assign_operator’ has no initializer on with gcc -v: Using built-in specs. COLLECT_GCC=/usr/bin/g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.2/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/src/gcc-4.7.2/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --enable-libstdcxx-time --enable-gnu-unique-object --enable-linker-build-id --with-ppl --enable-cloog-backend=isl --disable-ppl-version-check --disable-cloog-version-check --enable-lto --enable-gold --enable-ld=default --enable-plugin --with-plugin-ld=ld.gold --with-linker-hash-style=gnu --enable-multilib --disable-libssp --disable-build-with-cxx --disable-build-poststage1-with-cxx --enable-checking=release Thread model: posix gcc version 4.7.2 (GCC) I'm pretty certain that this code is valid C++ as it does compile in clang++ (built on top of this gcc version).
The code presented code example seems incomplete, because it is accepted as written. Here a complete code-example compiled with gcc 4.8.0 20121014 (experimental) using the compiler flags -Wall -std=c++11 -pedantic //--------------------- template<typename T> struct MemberGet{ static constexpr auto assign_operator = static_cast<T & (T::*)(const T &)>(&T::operator=); }; struct X {}; MemberGet<X> mg; //--------------------- "3|error: declaration of 'constexpr const auto MemberGet<X>::assign_operator' has no initializer|" I agree that this code should be accepted.
*** Bug 55159 has been marked as a duplicate of this bug. ***
Author: jason Date: Fri Feb 15 01:27:36 2013 New Revision: 196069 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196069 Log: PR c++/55003 * decl.c (cp_finish_decl): Force instantiation of an auto static data member. Added: trunk/gcc/testsuite/g++.dg/cpp0x/auto37.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/decl.c
Fixed.