[libcxx] Any plan to implement N3558?


Sorry I am new to C++ standardization process and clang development, I understand this proposal is not incorporated into the standard yet but it seems a very nice feature to have. My questions are:

  1. Does libcxx only provides what has been standardized? Or sometimes it will include experimental features (even not proposed by the clang/llvm team)?

  2. More specifically, do we have a plan to implement N3558? Or there is an implementation already exist but not to my knowledge, even if it outside libcxx. I know hpx (https://github.com/STEllAR-GROUP/hpx) has support to it, but just curios if there is any other support.

Sorry for the naive questions again. Thanks a lot for your patience.