https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79508
Bug ID: 79508
Summary: Parse error in template argument list using nested
template arguments
Product: gcc
Version: 6.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: trufanovan at gmail dot com
Target Milestone: ---
Created attachment 40738
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40738&action=edit
ii file
It's probably a regression.
I was trying to compile a popular opensourse project on my Kubuntu 16.10
4.8.0-38-generic with gcc 6.2.0 20161005 and got a compilation error.
The original problem was reported to project authors on GitHub:
https://github.com/JohnLangford/vowpal_wabbit/issues/1183
We found out that it's gcc version specific - it works for clang and gcc
4.6-4.9.
I've simplified the code. The sample to reproduce the problem is:
> code start: t.cpp
class C
{
public:
template< void(*F)()> void set_default() { }
};
template <class T> void random_positive()
{
}
template<class T> void initialize(T& x)
{
x.template set_default<random_positive<T> >();
}
int main ()
{
C x;
initialize<C>(x);
}
>code end: t.cpp
I'm getting
> compilation output:
t.cpp: In function ‘void initialize(T&)’:
t.cpp:18:12: error: parse error in template argument list
x.template set_default<random_positive<T> >();
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t.cpp:18:12: error: expected identifier
> compilation output end
Below are commad lines for old g++ and clangs that doesn't cause the problem so
produce no output to console + the command line of g++-6 with all verbose :
>truf@truf-laptop:~$ clear
>truf@truf-laptop:~$ /usr/bin/g++-4.6 -Wall -Wextra -c t.cpp -o t.o
>truf@truf-laptop:~$ /usr/bin/g++-4.8 -Wall -Wextra -c t.cpp -o t.o
>truf@truf-laptop:~$ /usr/bin/g++-4.9 -Wall -Wextra -c t.cpp -o t.o
>truf@truf-laptop:~$ /usr/bin/clang++-3.6 -Wall -Wextra -c t.cpp -o t.o
>truf@truf-laptop:~$ /usr/bin/clang++-3.8 -Wall -Wextra -c t.cpp -o t.o
>truf@truf-laptop:~$ /usr/bin/g++-6 -Wall -Wextra -c t.cpp -o t.o
t.cpp: In function ‘void initialize(T&)’:
t.cpp:18:12: error: parse error in template argument list
x.template set_default<random_positive<T> >();
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t.cpp:18:12: error: expected identifier
>truf@truf-laptop:~$ /usr/bin/g++-6 -v -save-temps -Wall -Wextra
>-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations -c t.cpp -o t.o
Using built-in specs.
COLLECT_GCC=/usr/bin/g++-6
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 6.2.0-5ubuntu12'
--with-bugurl=file:///usr/share/doc/gcc-6/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-6 --program-prefix=x86_64-linux-gnu- --enable-shared
--enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --disable-browser-plugin --enable-java-awt=gtk
--enable-gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-6-amd64/jre
--enable-java-home --with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-6-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-6-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--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 6.2.0 20161005 (Ubuntu 6.2.0-5ubuntu12)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-Wextra' '-fno-strict-aliasing'
'-fwrapv' '-fno-aggressive-loop-optimizations' '-c' '-o' 't.o' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/6/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE t.cpp -mtune=generic -march=x86-64 -Wall -Wextra
-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations
-fpch-preprocess -fstack-protector-strong -Wformat-security -o t.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/6"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/6/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/6
/usr/include/x86_64-linux-gnu/c++/6
/usr/include/c++/6/backward
/usr/lib/gcc/x86_64-linux-gnu/6/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/6/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-Wextra' '-fno-strict-aliasing'
'-fwrapv' '-fno-aggressive-loop-optimizations' '-c' '-o' 't.o' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/6/cc1plus -fpreprocessed t.ii -quiet -dumpbase
t.cpp -mtune=generic -march=x86-64 -auxbase-strip t.o -Wall -Wextra -version
-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations
-fstack-protector-strong -Wformat-security -o t.s
GNU C++14 (Ubuntu 6.2.0-5ubuntu12) version 6.2.0 20161005 (x86_64-linux-gnu)
compiled by GNU C version 6.2.0 20161005, GMP version 6.1.1, MPFR
version 3.1.5, MPC version 1.0.3, isl version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++14 (Ubuntu 6.2.0-5ubuntu12) version 6.2.0 20161005 (x86_64-linux-gnu)
compiled by GNU C version 6.2.0 20161005, GMP version 6.1.1, MPFR
version 3.1.5, MPC version 1.0.3, isl version 0.15
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: df259ea45bcfc8adc9cf4871d1d696af
t.cpp: In function ‘void initialize(T&)’:
t.cpp:18:12: error: parse error in template argument list
x.template set_default<random_positive<T> >();
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t.cpp:18:12: error: expected identifier
truf@truf-laptop:~$
