https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80451
--- Comment #8 from Денис Крыськов <krisk0.2017.02.27 at protonmail dot com> --- If I understand correctly, http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1579 is not implemented in gcc 5.4 and 6.3. Which means some code runs slower than is should. To be sure that a fast constructor is called, I need to delete slow constructor. Which results in bloated code (each and every class should contain delete statement). If that's not serious, that's unpleasant.
