LWG3868 Constrained algorithms should not require output_iterator

[jwakely]

https://cplusplus.github.io/LWG/issue3868

LWG would like LEWG to consider this Priority 4 issue at some point. Is this something we might want to do?

[frederick-vs-ja]

This may be related to P2550 (#1210).

[brycelelbach]

@inbal2l have Ranges see this first.

[dhollman]

SG9 and LWG met jointly in St. Louis to review this issue. We took the following poll:

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SG9 and LWG believe this is not a defect, but we do agree that there are inconsistencies that need a paper to address more thoroughly.

SF	F	N	A	SA
6	2	0	0	0

Unanimous consent