Re: [boost] [test] BOOST_TEST macro and std::max

Subject: Re: [boost] [test] BOOST_TEST macro and std::max
From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2016-01-11 04:51:15

2016-01-11 4:11 GMT+01:00 Gennadiy Rozental <rogeeff_at_[hidden]>:

> Benedek Thaler <thalerbenedek <at> gmail.com> writes:
>
> I believe at this point we understand WHAT is going on.
>
> >   auto const& E = ::boost::test_tools::assertion::seed()->*3u
> > == ((std::max)(0u, 3u));
>
> max returns unsigned int&&, which for some unclear reason is bound to
> unsigned int const& in expression template E. This obviously becomes
> dangling reference as soon as we leave this line.
>

This is an expected behavior in C++: an xvalue (rvalue reference returned
from a function) can be bound to a const lvalue reference. See example:
http://melpon.org/wandbox/permlink/yon7EWpj2B5KQNcT