Re: [boost] [type traits] possible bug in boost::is_convertible for types with private copy constructors

From: David Abrahams (dave_at_[hidden])
Date: 2008-06-26 09:19:02

Howard Hinnant <hinnant <at> twcny.rr.com> writes:

> The tr1::is_convertible, which was born from boost::is_convertible,  
> considers its "from" to be an lvalue when detecting convertibility.   
> The C++0X std::is_convertible considers its "from" to be an rvalue  
> when detecting convertibility.  If one wants to restrict  
> is_convertible to only consider lvalue froms, one simply specifies an  
> lvalue reference:  is_convertible<F&, T>::value  (from is now  
> considered as an lvalue).
> 
> There is motivation for this change here:
> 
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2255.html
> 
> (search for "is_convertible").

Very interesting!  But now the question is, how do we resolve this (and other
issues like it that will surely come up) for Boost?

--
Dave Abrahams
Boostpro Computing
http://www.boostpro.com