FYI, those papers (P0437R1 and P1370R1) have since been consolidated and superseded by P1841R0. Moreover, ...

...even P1841R0 is now dated. I enclose D1841R1, an updated draft, tentatively planned for publication next month. Private (off-list) comments welcome.

Finally, please note that this and many similar small-ish proposals are not considered a priority by WG21. LWG (WG21's Library Working Group) has a considerable backlog of such papers to review, some in their queue for years. It is therefore not currently predictable when any of these proposals will be given final consideration/approval, especially under the current circumstances that have already led to one WG21 meeting's cancellation.