Re: [boost] [optional] Changes in Boost.Optional

Subject: Re: [boost] [optional] Changes in Boost.Optional
From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2014-09-02 07:39:11

2014-09-02 11:23 GMT+02:00 Dean Michael Berris <mikhailberis_at_[hidden]>:

>
>
>
> > I just verified that your code example works with 1.55 on VS2010, so it
> is
> > a regression. I will not be able to have a look at it for the next couple
> > of days. I would like to determine why it even works on 1.55. The
> > converting constructor from arbitrary U is also explicit in 1.55, so it
> > works because of some sequence of conversions that I cannot figure out
> > right now.
> >
> >
> Right. My hunch is that 1.56 now has suppression for the cases where
> references would have been deduced (as discussed in
>
> http://www.boost.org/doc/libs/1_56_0/libs/optional/doc/html/boost_optional/dependencies_and_portability/optional_reference_binding.html
> ).
> Maybe the suppression applies even for the case when the conversion
> operator may have been useful for copy initialization.
>

However, it works fine with GCC. It looks like VC++ compiler has a bug in
overload resolution in copy initialization. It should never consider
explicit constructors.