[Bug libstdc++/70845] [6/7 Regression] inherited piecewise_construct_t constructor from std::pair by "using-declarations" is missing

[tuwwcn at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70845

--- Comment #8 from Wei-Wei Tu <tuwwcn at gmail dot com> ---
Would this bug be fixed in gcc 6.1.1 or in later version?