Boost::typeof compiler problem: mangling typeof, use decltype instead

Question

Hi,

short example:

#include <boost/typeof/typeof.hpp>
#include <boost/proto/core.hpp>
using namespace boost;


template<class T, class U>
BOOST_TYPEOF_TPL(T() + U()) add2(const T& t, const U& u)
{
    return t + u;
};

int main(){

     typedef BOOST_TYPEOF(add2(2.5, 1.5)) type; // get type -> works

     BOOST_STATIC_ASSERT((is_same<type, double>::value)); // check if double -> no error -> double

     double xxx = add2(1.5,1.5); // cause the problems
        return 0;
 }

When i try to compile this i become a error like:

g++-4.3: sorry, unimplemented: mangling typeof, use decltype instead

g++-4.2: internal compiler error: in write_type, at cp/mangle.c:1648 Please submit a full bug report, with preprocessed source if appropriate. See <URL:http://gcc.gnu.org/bugs.html&amp;gt; for instructions. For Debian GNU/Linux specific bug reporting instructions, see <URL:file:///usr/share/doc/gcc-4.2/README.Bugs>.

gcc version 4.3.2 (Debian 4.3.2-1.1) gcc version 4.2.4 (Debian 4.2.4-6)

Where is the Problem or what i do wrong?a

Answer 1

The example in the typeof documentation first wraps the BOOST_TYPEOF_TPL macro in a functor, then uses that when declaring the function. Does that work any better for you?

template<class T, class U>
struct result_of_add2
{
    typedef BOOST_TYPEOF_TPL(T() + U()) type;
};

template<class T, class U>
typename result_of_add2<T, U>::type add2(const T& t, const U& u)
{
    return t + u;
};