[Bug c++/60273] New: gcc gets confused when one class uses variadic

[Bug c++/60273] New: gcc gets confused when one class uses variadic

[walter.mascarenhas at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60273

            Bug ID: 60273
           Summary: gcc gets confused when one class uses variadic
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: walter.mascarenhas at gmail dot com

Created attachment 32171
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=32171&action=edit
gcc asked me to submit this file

//
// When compiling this file in Ubuntu 13.04, gcc 4.8.1 crashes with the
// following message. Clang 3.0 compiles the file with no problems.
//
// /home/walter/code/klein/tests/platform/gcc_bug/main.cc:-1: In instantiation
of 'struct Bar<Foo<int> >':
// /home/walter/code/klein/tests/platform/gcc_bug/main.cc:25: required from
here
// /home/walter/code/klein/tests/platform/gcc_bug/main.cc:20: internal compiler
error: Segmentation fault
//  template<int... Ns> using Buggy = typename X::template S<Ns...>;
// :-1: error: [main.o] Error 1^
//

struct A {};

template <class X>
struct Foo
{
  using Type = int;

  // if the next line is replaced by template <int... N> then all is fine
  template <int N1, int N2>
  using S = A;
};

template <class X>
struct Bar
{
  // if the next line is commented then all is fine.
  using Type = typename X::Type;

  // if the next line is commented then all is fine.
  template<int... Ns> using Buggy = typename X::template S<Ns...>;
};

void foobar()
{
  Bar< Foo<int> > bf;
}

[Bug c++/60273] gcc gets confused when one class uses variadic

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60273

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler@googlemail.
                   |                            |com

--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
My understanding is that your example is touching an open language issue,
namely

http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1430

The current tendency seems to be that this should be ill-formed (personally I'm
not happy with that decision). Current clang and gcc do both reject your code.
I suggest to mark this issue as deferred pending 1430.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idY933

--- Comment #11 from Mark Warner <warnerme at ptd dot net> ---
I'm confused .. what about..
for (k = i; k < (int)(sizeof(NSQ_del_dec_struct) / sizeof(opus_int32)); ++k)
... is illegal or invalid ?
Why does it only fail if -DDEBUG is defined ?
I mean, this code worked fine for months .. and now

[Bug c++/60273] gcc gets confused when one class uses variadic

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60273

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |SUSPENDED
   Last reconfirmed|                            |2014-02-19
                 CC|                            |mpolacek at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Ok, suspended for now.

[Bug c++/60273] [DR 1430] gcc gets confused when one class uses variadic

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60273

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The DR is still active but clang no longer accepts the code. and GCC no longer
crashes either.