Boost C++ Libraries: Ticket #13315: boost 1.65.1 gcc 5.4 redefinition error in boost/type_traits/is_unsigned.hpp

summary changed

anonymous — Fri, 01 Dec 2017 04:02:22 GMT

summary gcc 5.4 redefinition error in boost/type_traits/is_unsigned.hpp → boost 1.65.1 gcc 5.4 redefinition error in boost/type_traits/is_unsigned.hpp

Michel Morin — Fri, 01 Dec 2017 13:23:58 GMT

I think this is a compiler bug (though I don't understand what happens in the code). Here is a smaller testcase

#include <iostream>
typedef unsigned long long cl_ulong __attribute__((aligned(8)));
void f()
{
    // unsigned long long x; // OK
    cl_ulong x; // Error
    std::cout << x;
}
template <class T> struct is_unsigned {};
template <> struct is_unsigned<      unsigned long long> {};
template <> struct is_unsigned<const unsigned long long> {};

G++-5 fails to compile the code on C++11, 14, 17 modes with the following error messages

Line14: error: redefinition of 'struct is_unsigned<long long unsigned int>'
 template <> struct is_unsigned<const unsigned long long> {};
                    ^
Line13: error: previous definition of 'struct is_unsigned<long long unsigned int>'
 template <> struct is_unsigned<      unsigned long long> {};

Michel Morin — Tue, 05 Dec 2017 11:38:20 GMT

I reported the compiler bug to GCC as PR83248. There, I got this reply

GCC 5 is no longer maintained, if it is fixed in GCC 6 please use that.

GCC 6, 7, 8 do not have this compiler bug.

status changed; resolution set

John Maddock — Thu, 25 Jan 2018 10:53:21 GMT

status new → closed
resolution → wontfix

I'm going to close this, purely because I don't see any way to fix this without breaking other stuff... please file a PR if you see a way.