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

28 Sep 2017


      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