Re: [boost] [optional] get() misses optional r-value overload in contrast to operator* and value()

Subject: Re: [boost] [optional] get() misses optional r-value overload in contrast to operator* and value()
From: Peter Dimov (lists_at_[hidden])
Date: 2018-03-23 16:01:22

Andrzej Krzemienski wrote:

> > const auto& x = func0().value();
...
> I am convinced that you are hitting an UB. Temporary returned by func0() 
> is destroyed in the first line.

Interesting question. value() && returns T&&. The auto const& reference 
can't bind directly to T&&, because that's not an lvalue. So a temporary 
value of type T is created, and the auto const& binds to that, extending its 
life. That's of course assuming I read http://eel.is/c++draft/dcl.init.ref 
correctly.