[Bug c++/55931] New: Constexpr member function inside a static member is not working

["vince.rev at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55931

             Bug #: 55931
           Summary: Constexpr member function inside a static member is
                    not working
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: vince.rev@gmail.com


The call of a constexpr member of a class into a static member of the same
class is not working. This is illustrated by the following code:
(tested on g++ 4.7.1 and 4.7.2, but it may also affect g++ 4.8)

-------------------------------------------------------------------
#include <iostream>
#include <type_traits>

template<typename Type>
class Test
{
    public:
        constexpr Test(const Type val) : _value(val) {}
        constexpr Type get() const {return _value;}
        static void test()
        {
            static constexpr Test<int> x(42);
            std::integral_constant<int, x.get()> i; // This is not working
            std::cout<<i<<std::endl;
        }
    protected:
        Type _value;
};

int main(int argc, char *argv[])
{
    static constexpr Test<int> x(42);
    std::integral_constant<int, x.get()> i; // This is working
    std::cout<<i<<std::endl;
    Test<double>::test();
    return 0;
}
-------------------------------------------------------------------

which produces the following error:

-------------------------------------------------------------------
main.cpp: In static member function ‘static void Test<Type>::test()’:
main.cpp:13:48: erreur: invalid use of ‘Test<Type>::get<int>’ to form a
pointer-to-member-function
main.cpp:13:48: note:   a qualified-id is required
main.cpp:13:48: erreur: could not convert template argument
‘x.Test<Type>::get<int>()’ to ‘int’
main.cpp:13:51: erreur: invalid type in declaration before ‘;’ token
-------------------------------------------------------------------