[Bug c++/39658] New: "wrong number of template arguments" in variadic template specialization

[Bug c++/39658] New: "wrong number of template arguments" in variadic template specialization

[me22 dot ca at gmail dot com]

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vartembug.cxx:25: error: wrong number of template arguments (3, should be 4 or
more)
vartembug.cxx:8: error: provided for ‘template<bool found_label, bool
found_size, bool found_sign, bool found_endian, class ... Args> struct
bitstring_entry_attributes’

>From the following code:


template <
    bool found_label,
    bool found_size,
    bool found_sign,
    bool found_endian,
    typename... Args
>
struct bitstring_entry_attributes {
};

template <
    bool found_size,
    bool found_sign,
    bool found_endian,
    typename Arg,
    typename... Args
>
struct bitstring_entry_attributes<
    false,
    found_size,
    found_sign
    found_endian,
    Arg, 
    Args...
> {
};


$ g++-4.3.3 -v -save-temps -std=gnu++0x vartembug.cxx
Using built-in specs.
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-4.3.3-r2/work/gcc-4.3.3/configure --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.3.3
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.3
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.3/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.3.3/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--disable-fixed-point --enable-nls --without-included-gettext
--with-system-zlib --disable-checking --disable-werror --enable-secureplt
--enable-multilib --enable-libmudflap --disable-libssp --enable-libgomp
--enable-cld --disable-libgcj --enable-languages=c,c++,treelang --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.3.3-r2 p1.1,
pie-10.1.5'
Thread model: posix
gcc version 4.3.3 (Gentoo 4.3.3-r2 p1.1, pie-10.1.5) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=gnu++0x' '-shared-libgcc'
'-mtune=generic'
 /usr/libexec/gcc/x86_64-pc-linux-gnu/4.3.3/cc1plus -E -quiet -v -D_GNU_SOURCE
vartembug.cxx -D_FORTIFY_SOURCE=2 -mtune=generic -std=gnu++0x -fpch-preprocess
-o vartembug.ii
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include/g++-v4
 /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include/g++-v4/x86_64-pc-linux-gnu
 /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include/g++-v4/backward
 /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include
 /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.3/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=gnu++0x' '-shared-libgcc'
'-mtune=generic'
 /usr/libexec/gcc/x86_64-pc-linux-gnu/4.3.3/cc1plus -fpreprocessed vartembug.ii
-quiet -dumpbase vartembug.cxx -mtune=generic -auxbase vartembug -std=gnu++0x
-version -o vartembug.s
GNU C++ (Gentoo 4.3.3-r2 p1.1, pie-10.1.5) version 4.3.3 (x86_64-pc-linux-gnu)
        compiled by GNU C version 4.3.3, GMP version 4.2.4, MPFR version
2.4.1-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 99eb7989473b1a2e92eed91867d56b9a


Of interest is that removing 2 of the non-variadic arguments/parameters (giving
the following) compiles fine:


template <
    bool found_label,
    bool found_endian,
    typename... Args
>
struct bitstring_entry_attributes {
};

template <
    bool found_endian,
    typename Arg,
    typename... Args
>
struct bitstring_entry_attributes<
    false,
    found_endian,
    Arg, 
    Args...
> {
};


-- 
           Summary: "wrong number of template arguments" in variadic
                    template specialization
           Product: gcc
           Version: 4.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: me22 dot ca at gmail dot com
 GCC build triplet: x86_64-pc-linux-gnu
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39658