[Bug c++/55494] New: ICE for char array or int in variadic template

[Bug c++/55494] New: ICE for char array or int in variadic template

[jondreads at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55494

             Bug #: 55494
           Summary: ICE for char array or int in variadic template
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jondreads@gmail.com


The following code generates internal compiler error: in unify_one_argument, at
cp/pt.c:15267
The error is generated if the template argument to Foo is a char array or int.
It is not generated if it is a struct.

gcc version 4.7.2.20120921 (Red Hat 4.7.2-2)
Target: x86_64-redhat-linux



struct S {};

template <char const * Name>
struct Foo {};

template <typename...Args>
void operator<<(S& os, Foo<Args...>& m)
{
}

char test[] = "test";

int main()
{
    S s;
    Foo<test> m;
    s << m;
}

[Bug c++/55494] ICE for char array or int in variadic template

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-11-27
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.8.0
     Ever Confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-27 18:49:34 UTC ---
Reproduced with trunk.

[Bug c++/55494] ICE for char array or int in variadic template

[mpolacek at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55494

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> 2012-11-27 18:55:34 UTC ---
ICEs even with 4.7 branch.  With 4.6:

/home/marek/rh/tests/pr55494.C:6:19: warning: variadic templates only available
with -std=c++0x or -std=gnu++0x [enabled by default]
/home/marek/rh/tests/pr55494.C:7:35: sorry, unimplemented: cannot expand ‘Args
...’ into a fixed-length argument list
/home/marek/rh/tests/pr55494.C:7:35: error: type/value mismatch at argument 1
in template parameter list for ‘template<const char* Name> struct Foo’
/home/marek/rh/tests/pr55494.C:7:35: error:   expected a constant of type
‘const char*’, got ‘Args ...’
/home/marek/rh/tests/pr55494.C: In function ‘int main()’:
/home/marek/rh/tests/pr55494.C:17:10: error: no match for ‘operator<<’ in ‘s <<
m’
/home/marek/rh/tests/pr55494.C:17:10: note: candidate is:
/home/marek/rh/tests/pr55494.C:7:6: note: template<class ... Args> void
operator<<(S&, int&)

[Bug c++/55494] ICE for char array or int in variadic template

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55494

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
   Target Milestone|4.8.0                       |---

[Bug c++/55494] ICE for char array or int in variadic template

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55494

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |DUPLICATE

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-11-28 17:39:32 UTC ---
This is invalid and essentially equivalent to PR52844: operator<< takes as m a
Foo which is a (variadic) type template, but the Foo we are defining is a
non-type template. Note that when there are no variadic templates around these
testcases are simply rejected.

*** This bug has been marked as a duplicate of bug 52844 ***