[boost] Fusion and constexpr, C++11 support entirely broken on develop

Subject: [boost] Fusion and constexpr, C++11 support entirely broken on develop
From: Mathias Gaunard (mathias.gaunard_at_[hidden])
Date: 2014-10-05 18:44:25

Hi folks,

I recently decided to move all of my code to C++11, and I usually use 
the develop version of each library so that I can have the latest 
developments and can easily contribute.

However, Fusion appears to be fundamentally broken on develop whenever 
C++11 is enabled with GCC. It works fine with C++03.

I don't think this is a situation that should ever happen; while develop 
is for libraries undergoing development, it shouldn't be totally broken 
either.

In particular, the problem is that it uses BOOST_CONSTEXPR in contexts 
where C++11-constexpr is invalid, but where it is valid in C++14.

Should there be a separate BOOST_CONSTEXPR14 macro?