Boost C++ Libraries: Ticket #13108: BOOST_STATIC_ASSERT occurs when serializing a class with default constructor explicitly defined

version changed

anonymous — Thu, 06 Jul 2017 09:03:31 GMT

version Boost 1.63.0 → Boost 1.64.0

Wed, 12 Jul 2017 19:17:16 GMT

Same issue occurs for g++ 4.6.4 (with -std=c++0x). It looks like boost::serialization::detail::is_default_constructible falls into using boost::has_trivial_constructor; however, it may be that this just does not fully work for these compilers (see docs: http://www.boost.org/doc/libs/1_64_0/libs/type_traits/doc/html/boost_typetraits/reference/has_trivial_constructor.html)

Oddly enough the constructor declared with = default passes on g++ 4.6.4; e.g.
( g++-4.6 -W -Wall -std=c++0x ... )

#include "boost/serialization/detail/is_default_constructible.hpp"
#ifndef BOOST_HAS_TRIVIAL_CONSTRUCTOR
#error
#endif
struct T
{
  T() = default;
};
struct X
{
  X() {}
};
int main(int argc, char *argv[])
{
  (void)argc; (void)argv;
  static_assert(BOOST_HAS_TRIVIAL_CONSTRUCTOR(T), "t fail");
  static_assert(BOOST_HAS_TRIVIAL_CONSTRUCTOR(X), "x fail");
}

boost_htd.cpp:22:3: error: static assertion failed: "x fail"

status changed; resolution set

Robert Ramey — Fri, 11 Aug 2017 11:30:33 GMT

status new → closed
resolution → wontfix

This is just a limitation of older compilers. The explanation can be found at https://github.com/boostorg/serialization/blob/develop/include/boost/serialization/detail/is_default_constructible.hpp

I'm sorry there is just no way to fix it other than not explicitly defining a default constructor which you shouldn't need to do anyway.