[Bug c++/11077] New: enumerator value in template not assignable from bool

[Bug c++/11077] New: enumerator value in template not assignable from bool

[numerical.simulation@web.de]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077

           Summary: enumerator value in template not assignable from bool
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P2
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: numerical.simulation@web.de
                CC: gcc-bugs@gcc.gnu.org,numerical.simulation@web.de
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu

The following code does not compile with gcc, though it is valid C++ (IMHO)

#include <iostream>

template<class T> 
class has_member_disambiguation // Thanks to Paul Mensonides
{
protected:
  template<class U> static char check(typename U::Disambiguation*);
  template<class U> static char (& check(...))[2];

public:
  enum { value = (sizeof(check<T>(0)) == 1) };
};

struct A 
{
  typedef double Disambiguation;
};

struct B {};


int main()
{
  std::cerr << has_member_disambiguation<A>::value << std::endl;
  std::cerr << has_member_disambiguation<B>::value << std::endl;
}


g++ ~/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C: In instantiation of
`has_member_disambiguation<A>':
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:24:   instantiated from
here
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:11: error: invalid use of 
   undefined type `class has_member_disambiguation<A>'
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:5: error: declaration of `
   class has_member_disambiguation<A>'
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:11: error: enumerator 
   value for `value' not integer constant
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C: In instantiation of
`has_member_disambiguation<B>':
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:25:   instantiated from
here
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:11: error: invalid use of 
   undefined type `class has_member_disambiguation<B>'
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:5: error: declaration of `
   class has_member_disambiguation<B>'
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:11: error: enumerator 
   value for `value' not integer constant



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[Bug c++/11077] enumerator value in template not assignable from bool

[pinskia@physics.uc.edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077


pinskia@physics.uc.edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|blocker                     |major
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-06-03 12:36:39
               date|                            |


------- Additional Comments From pinskia@physics.uc.edu  2003-06-03 12:36 -------
I am going to assume this is valid C++ 
It happens on 2.95.3, 3.0.4, 3.2.3, 3.3.1 (20030526) and the mainline (20030602).



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[Bug c++/11077] enumerator value in template not assignable from bool

[reichelt@gcc.gnu.org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077


reichelt@gcc.gnu.org changed:

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


------- Additional Comments From reichelt@gcc.gnu.org  2003-06-03 12:42 -------
This is essentially the same problem as in PR 9259.
Even Giovanni's workaround is applicable here: Write

sizeof(has_member_disambiguation::template check<T>(0))

instead of

sizeof(check<T>(0))



*** This bug has been marked as a duplicate of 9259 ***



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[Bug c++/11077] enumerator value in template not assignable from bool

[numerical.simulation@web.de]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077



------- Additional Comments From numerical.simulation@web.de  2003-06-03 13:14 -------
Subject: Re:  enumerator value in template not assignable from 
 bool

"reichelt@gcc.gnu.org" wrote:

> This is essentially the same problem as in PR 9259.
> Even Giovanni's workaround is applicable here: Write
>
> sizeof(has_member_disambiguation::template check<T>(0))
>
> instead of
>
> sizeof(check<T>(0))

Nope, with the workaround You get an ICE:

[...]
 enum { value = (sizeof(has_member_disambiguation::template check<T>(0)) == 1) };
[...]


g++ ~/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C: In instantiation of `has_member_disambiguation<A>':
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:24:   instantiated from here
/home/markus/hp-home/C++/EXPERIMENTAL/GCC-3.4-Bugs.C:11: internal compiler error: Segmentation
   fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.gnu.org/softwa


Markus





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[Bug c++/11077] enumerator value in template not assignable from bool

[pinskia@physics.uc.edu]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077



------- Additional Comments From pinskia@physics.uc.edu  2003-06-03 13:23 -------
Actually with the workaround I do not get an ICE but on 3.3.1 (20030526) the code is accepted but 
on the mainline (20030603) it is rejected:
tin:~/src/gnu/gcctest>~/ia32_linux_gcc3_3/bin/gcc pr11077.cc -c 
tin:~/src/gnu/gcctest>gcc pr11077.cc -c
pr11077.cc:13: error: expected primary-expression
pr11077.cc: In instantiation of `has_member_disambiguation<A>':
pr11077.cc:26:   instantiated from here
pr11077.cc:13: error: enumerator value for `value' not integer constant
pr11077.cc: In instantiation of `has_member_disambiguation<B>':
pr11077.cc:27:   instantiated from here
pr11077.cc:13: error: enumerator value for `value' not integer constant



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[Bug c++/11077] enumerator value in template not assignable from bool

[giovannibajo@libero.it]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11077



------- Additional Comments From giovannibajo@libero.it  2003-06-03 17:13 -------
The failure Andrew reported on the mainline (sizeof treated as non-constant) is 
already covered by c++/9907. I'm sure there is at least a syntax of 
has_member_xxxx that works with GCC 3.4, but I can't find it in my notes. I 
suggest the poster to try tweaking the sample a bit.

Since there are no new failures in this bug, it's ok to keep it closed as a 
duplicate.



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