Re: [boost] [contract] auto_..._error regression tests fail on C++1z

Subject: Re: [boost] [contract] auto_..._error regression tests fail on C++1z
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2017-09-28 23:09:04

AMDG

On 09/28/2017 04:58 PM, Lorenzo Caminiti via Boost wrote:
> <snip>
> 
> Correctly it does not compile up to C++1y because main cannot access
> the copy operations:
> 
>     $ clang++ -std=c++1y 05.cpp
>     05.cpp:14:15: error: calling a private constructor of class 'x'
>         auto xx = f();
>                   ^
>     05.cpp:5:5: note: declared private here
>         x(x const&) {}
>         ^
>     1 error generated.
> 
> However, it compiles on C++1z?!
> 
>     $ clang++ -std=c++1z 05.cpp
>     # Not compiler errors?!
> 
> Why... what changed in C++1z that makes the above compile? How can I
> prevent copying x outside its friend function f in C++1z?
> 

  This code no longer makes a copy, and
does not require the copy constructor.

In Christ,
Steven Watanabe