[Bug c++/81952] copy elision used when constructor needs to be called

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81952

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot 
gnu.org
             Status|NEW                         |ASSIGNED
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed by

commit 2170d4b6ddca526b53e87215dbf6fab5973000c7
Author: Jason Merrill <ja...@redhat.com>
Date:   Wed Mar 21 23:53:19 2018 -0400

    PR c++/81311 - wrong C++17 overload resolution.

            * call.c (build_user_type_conversion_1): Remove C++17 code.
            (conv_binds_ref_to_prvalue): New.
            (build_over_call): Handle C++17 copy elision.
            (build_special_member_call): Only do C++17 copy elision here if the
            argument is already the right type.

    From-SVN: r258755

Adjusted test:

template <class T>
struct opt {
    opt() { }
    opt(opt const& ) { __builtin_abort (); }
    opt(opt&& ) { __builtin_abort (); }

    template <class U>
    opt(U&& ) { }
};

struct foo 
{
    explicit operator opt<int>() { __builtin_abort (); return {}; }
};

int main()
{
    opt<int> o(foo{});
}