EWG-I in Prague

Forward D0870R2 to EWG, as we believe that EWGI cannot provide any further useful feedback to the author.

EWG Prague Friday afternoon:

D0870R2 A proposal for a type trait to detect narrowing conversions

Send to SG6 Numerics for input.

We have no concerns with this, only send this paper back to us if SG6 or LEWG / LWG / CWG ask.

Prague 2020-02 LEWGI Minutes

P0870R1 std::is_narrowing_conversion: Direction Review

Chair: Billy Baker

Champion: Marc Mutz

Minute Taker: David Olsen

Start Review: 2020-02-11 08:39

You mentioned that there are proposed changes to what are narrowing conversions in flight? Do we expect the definition to change again in the future?

Does EWG(I) need to see this?

Start Polling: 9:14

POLL: We should promise more committee time to pursuing P0870, knowing that our time is scarce and this will leave less time for other work.

Attendance: 20

# of Authors: 1

Author Position: SF

End: 9:16

CONSENSUS: Bring a revision of P0870R1 (std::is_narrowing_conversion) to EWGI for review, and then revise, with the guidance below, and return to LEWGI for further design review.

• Paper authors are encouraged to provide a better example of an implementation.
• Paper authors are encouraged to provide a revision history.
• Paper authors are encouraged to provide additional references in P0870 to papers related to narrowing conversions that were mentioned during the discussion such as P1818.

P0870R2 A proposal for a type trait to detect narrowing conversions (Giuseppe D'Angelo)

P0870R3 A proposal for a type trait to detect narrowing conversions (Giuseppe D'Angelo)

2022-10 Library Evolution Electronic Poll Outcomes

Send [P0870R4] is_convertible_without_narrowing to Library Working Group for C++26, classified as an addition ([P0592R4] bucket 3 item).

Outcome: Strong consensus in favor.

@cor3ntin I believe the above is a C&P mistake? I've got 9/6/1/0/0 (the outcomes paper isn't published yet, so I can't check against an authoritative reference...)

Indeed, thanks for noticing.

P0870R5 A proposal for a type trait to detect narrowing conversions (Giuseppe D'Angelo)

Hi @brycelelbach @cor3ntin ; during the review of this paper in Issaquah it's been requested whether LEWG could confirm a design choice.

To this end, I've uploaded R5. It does not change any design / behavior from R4, but it adds a paragraph that elaborates on the design choice mentioned above: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p0870r5.html#ch5.9

I guess this paper should go back to LWG only if LEWG can confirm that the choice was the intended one.

This paper is now in the custody of Library Evolution.

@inbal2l and @cor3ntin this can be handled with a mailing list review. It should get higher priority than others, as it's just a design clarification.

As P2280 was approved for C++26, the author would like to make design adjustments accordingly.
P0870R6 will be seen by LEWG when published.

P3146 (#1797) Proposes a change to support this paper.