d069df01ed
* include/std/variant (__overload_set): Remove. (_Arr): New helper. (_Build_FUN): New class template to define a single FUN overload, with specializations to prevent unwanted conversions, as per P0608R3. (_Build_FUNs): New class template to build an overload set of FUN. (_FUN_type): New alias template to perform overload resolution. (__accepted_type): Use integer_constant base for failure case. Use _FUN_type for successful case. (variant::__accepted_index): Use _Tp instead of _Tp&&. (variant::variant(_Tp&&)): Likewise. (variant::operator=(_Tp&&)): Likewise. From-SVN: r271296