DE-115 26.7.6.1 [range.all.general], 26.4.5 [range.refinements] Copyable and movable views

[wg21bot]

P1456 has created several inconsistencies in how copyable views and move-only views are used (and treated in generic contexts). These have wide-ranging implications for all generic ranges code, even ranges code where the properties copyable/move-only and view/non-view are entirely irrelevant

Apply P2636.

[brycelelbach]

The proposed resolution is to adopt P2636 https://github.com/cplusplus/papers/issues/1302

[inbal2l]

Scheduled for SG9's meeting in Kona, first session (08:00-9:45): https://wiki.edg.com/bin/view/Wg21kona2022/SG9

[inbal2l]

Reviewed by SG9 at Kona2022 meeting (Full Minutes).

Polls

POLL: We support applying the resolution for “DE#472: DE-115 26.7.6.1 [range.all.general], 26.4.5 [range.refinements] copyable and movable views” (Apply P2636R1) for C++23.

SF	F	N	A	SA
1	0	2	5	2

Attendance: 18 (10 on-site, 8 remotely)

# of Authors: 1

Author’s position: SF

Outcome: Consensus Against

Summary

We had a broad discussion, on which we've seen examples of the issue (unexpected behavior for some of the ranges, which does not qualify as views).

The poll results suggest that SG9 Does not support applying the change proposed. The main concern was that the change conflicted with the fundamental attributes of views.

The issue was forwarded to LEWG.

[brycelelbach]

New design questions have arisen, and as such this has been returned to the Ranges Study Group.

[inbal2l]

Re-reviewed by SG9 on January 2nd (Full Minutes)

LEWG has asked that the author will address the comments and update the paper, and then SG9 will have an additional discussion, to see if opinions have changed. From reading the room (and emails), the opinions haven’t shifted.

The NB comment is passed back to LEWG with the “no change in SG9's opinion”. Moving this back to LEWG to decide if they want to see it again or close the NB comment as "rejected".

[brycelelbach]

I got this mixed up with another issue. We'll look at it in Library Evolution.

[brycelelbach]

The author is no longer pursuing the paper for this NB comment, as there was no consensus for it. We should reject the comment; Library Evolution will briefly discuss this at the 2023-02 Issaquah meeting.

[brycelelbach]

2023-02-06 10:30 to 12:00 Issaquah Library Evolution Meeting

DE-115: Copyable and Movable Views

2023-02-06 10:30 to 12:00 UTC-8 Issaquah Library Evolution Minutes

Champion: Inbal Levi (IP)

Chair: Bryce Adelstein Lelbach (IP) & Ben Craig (IP)

Minute Taker: Steve Downey (IP)

Start: 2023-02-06 10:44 UTC-8

POLL: Reject C++23 National Body comment DE-115 (Copyable and Movable Views).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
5	12	3	1	0

Attendance: 20 (in person) + 9 (remote)

# of Authors: 0

Author Position: N/A

Outcome: Consensus in favor.

WA: I believe the issue is a real problem we should fix. But I can accept not doing something about this.

End: 10:50

Next Steps

Reject C++23 National Body comment DE-115 (Copyable and Movable Views).

[jensmaurer]

Rejected. There was no consensus for a change.