P1938 if consteval

[wg21bot]

P1938R0 if consteval (Barry Revzin, Daveed Vandevoorde, Richard Smith)

[jfbastien]

See the polls from the Belfast discussion of FR222:
cplusplus/nbballot#219 (comment)

[jfbastien]

EWG Prague on Friday morning:

Reviewing R1 of the paper, which wasn’t in the mailing. Can’t poll for tentative ready in this meeting.

We are interested in some solution in the space which this paper tackles, either as proposed in the paper or in some other form.

SF	F	N	A	SA
21	19	0	0	0

Consensus.

We want to pursue this paper for C++23.

SF	F	N	A	SA
10	6	15	2	0

Given how many neutrals we have here, and none in the first poll, this isn't consensus. People interested in other options should come with new information by next meeting to help increase consensus.

[wg21bot]

P1938R1 if consteval (Barry Revzin, Daveed Vandevoorde, Richard Smith, Andrew Sutton)

[jfbastien]

Discussed in today's EWG telecon. Polls:

if consteval should be parenthesized as if (consteval) ...

SF	F	N	A	SA
1	1	3	10	5

if consteval should not require braces, making this valid: if consteval boom(); else bam();

SF	F	N	A	SA
1	3	5	7	4

if consteval is tentatively ready to be voted on to forward to Core, after updating the paper as discussed

SF	F	N	A	SA
10	11	1	0	0

[wg21bot]

P1938R2 if consteval (Barry Revzin, Daveed Vandevoorde, Richard Smith, Andrew Sutton)

[jfbastien]

EWG February 2021 polls:

Poll: Forward P1938R2 "if consteval" to Core.

SF	F	N	A	SA
20	7	2	0	0

Poll outcome: ✅ consensus.

Salient comments:

• The number of experts who have been confused by is_constant_evaluated suggests that this is a much safer spelling for the utility.
• Makes metaprogramming more accessible and its code more readable, better composability.
• Sad that this wasn’t in C++20.

[jensmaurer]

CWG 2021-03-22: Approved D1938R3.

[JeffGarland]

LWG review planned for 2021-04-02

[jwakely]

LWG review planned for 2021-04-02

Change of plan, 2021-04-09 instead.

[JeffGarland]

Now schedule 2021-04-16

[JeffGarland]

LWG reviewed and adopted library wording.

https://wiki.edg.com/bin/view/Wg21telecons2021/P1938-20210416

Adopt P1938R3 if consteval for c++23
No objection to unanimous consent

[wg21bot]

P1938R3 if consteval (Barry Revzin, Daveed Vandevoorde, Richard Smith, Andrew Sutton)

[wg21bot]

Adopted 2021-06.