[Bug c++/65790] New: compilation error std::index_sequnece

[Bug c++/65790] New: compilation error std::index_sequnece

[faithandbrave at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

            Bug ID: 65790
           Summary: compilation error std::index_sequnece
           Product: gcc
           Version: 4.9.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: faithandbrave at gmail dot com

Compilation error follow code:

#include <iostream>
#include <utility>

void g(std::size_t a, std::size_t b, std::size_t c)
{
  std::cout << a << ", " << b << ", " << c << std::endl;
}

//template <class T, T... Seq>
//void f(std::integer_sequence<T, Seq...>) // OK
template <std::size_t... Seq>
void f(std::index_sequence<Seq...>) // NG
{
  g(Seq...);
}

int main()
{
  f(std::index_sequence<0, 1, 2>());
}


error message:
prog.cc: In function 'void f(std::index_sequence<Seq ...>)':
prog.cc:14:11: error: too few arguments to function 'void g(std::size_t,
std::size_t, std::size_t)'
   g(Seq...);
           ^
prog.cc:4:6: note: declared here
 void g(std::size_t a, std::size_t b, std::size_t c)
      ^

I think this is compiler's issue, not libstdc++.

[Bug c++/65790] compilation error : receive std::index_sequnece

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-04-17
     Ever confirmed|0                           |1
      Known to fail|                            |4.8.3, 4.9.2, 5.0, 6.0

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Confirmed, Clang and EDG accept this:

extern "C" int printf(const char* ...);

namespace std
{
  typedef decltype(sizeof(0)) size_t;

  template<typename _Tp, _Tp... _Idx>
    struct integer_sequence
    {
      typedef _Tp value_type;
      static constexpr size_t size() { return sizeof...(_Idx); }
    };

  template<size_t... _Idx>
    using index_sequence = integer_sequence<size_t, _Idx...>;
}

void g(std::size_t a, std::size_t b, std::size_t c)
{
  printf("%zu, %zu, %zu\n", a, b, c);
}

template <std::size_t... Seq>
void f(std::index_sequence<Seq...>)
{
  g(Seq...);
}

int main()
{
  f(std::index_sequence<0, 1, 2>());
}

[Bug c++/65790] compilation error : receive std::index_sequence

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> ---
This is fixed for 5.2. Let's add the testcase and close the bug.

[Bug c++/65790] compilation error : receive std::index_sequence

[paolo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

--- Comment #3 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> ---
Author: paolo
Date: Thu Jul  9 09:51:09 2015
New Revision: 225607

URL: https://gcc.gnu.org/viewcvs?rev=225607&root=gcc&view=rev
Log:
2015-07-09  Paolo Carlini  <paolo.carlini@oracle.com>

        PR c++/65790
        * g++.dg/cpp0x/vt-65790.C: New.

Added:
    trunk/gcc/testsuite/g++.dg/cpp0x/vt-65790.C
Modified:
    trunk/gcc/testsuite/ChangeLog

[Bug c++/65790] compilation error : receive std::index_sequence

[paolo.carlini at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |5.2

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> ---
Done.

[Bug c++/65790] compilation error : receive std::index_sequence

[faithandbrave at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65790

--- Comment #5 from Akira Takahashi <faithandbrave at gmail dot com> ---
Thanks Paolo!!