http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53531
Niels Penneman <niels at penneman dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |niels at penneman dot org
--- Comment #1 from Niels Penneman <niels at penneman dot org> 2012-07-10
10:37:34 UTC ---
Exactly the same behavior with both 4.6.3 and 4.7.1
Similar test case below. Adding a trailing comma to a list of template
arguments breaks the code but compiles successfully and without warnings. A
trailing comma in a template list of for instance boost::mpl::vector will make
the vector "empty".
#########################
template <typename ... Ts>
struct S;
template <typename T, typename ... Ts>
struct S<T, Ts ...> { static constexpr int count = S<Ts ...>::count + 1; };
template <typename T>
struct S<T> { static constexpr int count = 1; };
int main()
{
return S<char, int, long,>::count;
}
#########################
$ g++ -v
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.6.3/g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.6.3/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.6.3/work/gcc-4.6.3/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.6.3
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.6.3
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.6.3/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.6.3/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.6.3/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--disable-fixed-point --with-ppl --with-cloog --disable-ppl-version-check
--with-cloog-include=/usr/include/cloog-ppl --enable-lto --enable-nls
--without-included-gettext --with-system-zlib --enable-obsolete
--disable-werror --enable-secureplt --enable-multilib --disable-libmudflap
--disable-libssp --enable-libgomp
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.6.3/python
--enable-checking=release --disable-libgcj --disable-libquadmath
--enable-languages=c,c++ --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --enable-targets=all
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.6.3 p1.3,
pie-0.5.2'
Thread model: posix
gcc version 4.6.3 (Gentoo 4.6.3 p1.3, pie-0.5.2)
$ g++ -v
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.1/g++
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.7.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.7.1/work/gcc-4.7.1/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.1
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.1/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.1
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.1/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.1/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.1/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--disable-fixed-point --with-ppl --with-cloog --disable-ppl-version-check
--with-cloog-include=/usr/include/cloog-ppl --enable-lto --enable-nls
--without-included-gettext --with-system-zlib --enable-obsolete
--disable-werror --enable-secureplt --enable-multilib
--with-multilib-list=m32,m64 --disable-libmudflap --disable-libssp
--enable-libgomp
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.7.1/python
--enable-checking=release --disable-libgcj --disable-libquadmath
--enable-languages=c,c++ --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --enable-targets=all
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.7.1 p1.0,
pie-0.5.3'
Thread model: posix
gcc version 4.7.1 (Gentoo 4.7.1 p1.0, pie-0.5.3)
#########################
Command: g++ -Wall -Wextra -std=c++0x undef.cpp
Output: none, completes succesfully
Command: ./a.out ; echo $?
Output: 0
When omitting the trailing comma, return status of compiled application is 3 as
expected.
