Re: [boost] "is-assignable" compile error using Boost 1.68 / LLVM-Clang / Windows

Subject: Re: [boost] "is-assignable" compile error using Boost 1.68 / LLVM-Clang / Windows
From: Gavin Lambert (boost_at_[hidden])
Date: 2018-09-20 05:40:19

On 20/09/2018 16:47, Adam Hartshorne wrote:
> Looks like boost::variant is the problem.

No, those are just plain includes.  Nothing to see there.

> 2>C:\boost_1_68_0\boost/type_traits/has_trivial_move_assign.hpp(49): error
> : no template named 'is_assignable'; did you mean 'std::is_assignable'?
> 2>C:\boost_1_68_0\boost/type_traits/intrinsics.hpp(233):  note: expanded
> from macro 'BOOST_HAS_TRIVIAL_MOVE_ASSIGN'

The problem is actually here.

As degski suggests, it's probably a compiler detection quirk where the 
BOOST_HAS_TRIVIAL_MOVE_ASSIGN macro has been defined because 
__has_feature exists but <boost/type_traits/is_assignable.hpp> was not 
included because __clang doesn't exist.  Or something like that.

This usually doesn't happen when using MSVC or Clang directly, but since 
you're using a hybrid the logic is confused.