[Motions 2026 03 lwg 2] P4146R0 C++ Standard Library Immediate Issues by burblebee · Pull Request #8935 · cplusplus/draft

burblebee · 2026-04-09T14:05:23Z

Fixes #8836.

Fixes NB RU 268 (C++26 CD).

…e first range is input and one of the ranges is empty

…lity Fixes NB US 135-216, US 136-217 (C++26 CD).

…g std::inplace_vector

…s return void

…types

Fixes NB US 242-372 (C++26 CD).

jwakely

Some changes, some comments not requiring actions, and some questions.

jwakely · 2026-04-14T12:37:47Z

+After that invokes \tcode{\exposid{handle}.resume()}.
+\end{itemdescr}
+
+\indexlibrarymember{\exposid{get-stop-token}}{task::\exposid{state}}%


Should this exposition-only member function be indexed? Huh, we do it for lots of others ... OK then.

jwakely · 2026-04-14T12:43:17Z

 Otherwise, it is expression-equivalent to
 \tcode{\exposid{MANDATE-NOTHROW}(rcvr.set_value(vs...))}.

+\mandates


Do we want a new paragraph for this? The issue doesn't request it, and some other places in [exec] have Mandates attached to other paragraphs (or list items), so I'm not sure.

Suggested change

\mandates

\pnum

\mandates

If we do it here, we should do it below as well.

(Maybe our library element macros like \mandates and \expects should have an implicit \pnum, and then have a raw form for cases like this and [structure.specifications] and [exec.get.fwd.progress] p2 where we don't want a new paragraph and a pnum.)

This is a weird case where we're not in an itemdescr, so our existing guidance doesn't really apply. I thought we'd just go with what's in the paper, but I agree that this sitution could do with some thought.

[exec] has quite a lot of these cases.

Alright, OK. That's certainly one less discrepancy with how it's used inside itemdecls.

But let's do that later, since it touches a lot of pre-existing mandates.

I think I count 16 occurrences of \mandates without preceding \pnum.

jwakely · 2026-04-14T13:45:04Z

 returns an object \exposid{V} such that
 \tcode{\exposid{V}.data()[\exposid{V}.size()]} equals \tcode{'\textbackslash 0'}.
+Each element of the range
+\tcode{\exposid{V}.data() +} \range{0}{\exposid{V}.size()}


This should be a closed range, not half-open, and the + should be math font not code font:

Suggested change

\tcode{\exposid{V}.data() +} \range{0}{\exposid{V}.size()}

$\tcode{\exposid{V}.data()} + \crange{0}{\exposid{V}.size()}$

We have the \countedrange macro for X+[0,n) but it always uses a half-open range. We could add \countedcrange for X+[0,n] but I think this is the only place we need it.

Did we have to say it so weirdly? Why not [V.data(), V.data() + V.size()]...? I understand the appeal of "itetor plus range" notation when it's elegant and compact, but here we already have to say two member function calls of V anyway...

Fixes NB US 257-382 (C++26 CD). Editorial note: * [task.state] Insert comma in "if ... is true, returns ...". * [task.state] Change "After that" to "Finally,".

…arantee

…constraints

… min/max considerations Fixes NB US 142-236 (C++26 CD).

Fixes NB US 249-379 (C++26 CD).

… requests to spawned work [exec.spawn.future] "receiver" in struct "future-operation" renamed to "receiverx" due to concept of same name.

…in_out_result

Fixes NB GB 07, GB 11 (C++26 CD).

… memory contents

…to concat_view Fixes NB FR 025-246 (C++26 CD).

Fixes NB US 139-232 (C++26 CD).

Fixes NB US 81-149 (C++26 CD).

Fixes NB US 75-138 (C++26 CD).

burblebee marked this pull request as ready for review April 9, 2026 14:26

eisenwave added this to the post-2026-03 milestone Apr 12, 2026

tkoeppe force-pushed the motions-2026-03-lwg-2 branch from 29c2e35 to ed9db42 Compare April 12, 2026 20:19

burblebee added 4 commits April 12, 2026 21:19

LWG3662 basic_string::append/assign(NTBS, pos, n) suboptimal

9d7581a

Fixes NB RU 268 (C++26 CD).

LWG3777 Common cartesian_product_view produces an invalid range if th…

581d0cb

…e first range is input and one of the ranges is empty

LWG3797 elements_view insufficiently constrained

a50b69c

LWG3891 LWG 3870 breaks std::expected<cv T, E>

4fa9e57

tkoeppe force-pushed the motions-2026-03-lwg-2 branch 2 times, most recently from 45d9c2d to b87b2ae Compare April 13, 2026 22:43

burblebee added 9 commits April 14, 2026 12:20

LWG4026 Assignment operators of std::expected should propagate trivia…

13b42a2

…lity Fixes NB US 135-216, US 136-217 (C++26 CD).

LWG4122 Ill-formed operator<=> can cause hard error when instantiatin…

328a4ba

…g std::inplace_vector

LWG4133 awaitable-receiver's members are potentially throwing

bdf1618

LWG4143 execution::set_value/set_error/set_stopped/start should alway…

0e20a6f

…s return void

LWG4151 Precondition of inplace_vector::swap

3660fae

LWG4223 Deduction guides for maps are mishandling tuples and references

e48c085

LWG4314 Missing move in mdspan layout mapping::operator()

a5f6c0a

LWG4325 std::indirect's operator== still does not support incomplete …

833d635

…types

LWG4339 task's coroutine frame may be released late

0f85741

Fixes NB US 242-372 (C++26 CD).

jwakely reviewed Apr 14, 2026

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Comment thread source/utilities.tex Outdated

jwakely reviewed Apr 14, 2026

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Comment thread source/containers.tex

jwakely requested changes Apr 14, 2026

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tkoeppe force-pushed the motions-2026-03-lwg-2 branch 3 times, most recently from 41d414d to 5f316fe Compare April 18, 2026 00:07

tkoeppe requested a review from jwakely April 18, 2026 00:09

burblebee added 5 commits April 18, 2026 01:09

LWG4347 task's stop source is always created

c17bca7

Fixes NB US 257-382 (C++26 CD). Editorial note: * [task.state] Insert comma in "if ... is true, returns ...". * [task.state] Change "After that" to "Finally,".

LWG4354 Reconsider weakly_parallel as the default forward_progress_gu…

8d7c659

…arantee

LWG4361 awaitable-receiver::set_value should use Mandates instead of …

f58eab0

…constraints

LWG4379 hive::reserve() needs Throws: element adjusted to match block…

97afbaf

… min/max considerations Fixes NB US 142-236 (C++26 CD).

LWG4476 run_loop should not have a set_error completion

a74041f

burblebee added 19 commits April 18, 2026 01:09

LWG4478 meta::has_identifier is not specified for annotations

02f14fa

LWG4485 Move specification for task::stop_token_type

be54f1d

Fixes NB US 249-379 (C++26 CD).

LWG4497 std::nullopt_t should be comparable

df6b8a7

LWG4504 Wording problem in {simple_}counting_scope

016c5d0

LWG4506 source_location is explicitly unspecified if is constexpr or not

053c967

LWG4532 Imprecise std::polymorphic wording seems to imply slicing

17eeaae

LWG4533 not_fn<f> is unimplementable

b1fe775

LWG4537 Improve define_static_array

7428f28

LWG4540 future-senders returned from spawn_future do not forward stop…

6592e5d

… requests to spawned work [exec.spawn.future] "receiver" in struct "future-operation" renamed to "receiverx" due to concept of same name.

LWG4544 Parallel overload of ranges::set_difference should return in_…

6f32a23

…in_out_result

LWG4548 Parallel ranges::set_intersection should not do unnecessary work

9fb8e24

LWG4549 vprint_nonunicode_buffered ignores its stream parameter

e02c5da

LWG4550 Need new feature test macros for <stdckdint.h> and <stdbit.h>

93ef426

Fixes NB GB 07, GB 11 (C++26 CD).

LWG4552 compare_exchange_weak writes a value on spurious failure, not…

6344104

… memory contents

LWG4553 Wording for FR-025-246 25.7.18.2 Add a reserve_hint function …

9bee954

…to concat_view Fixes NB FR 025-246 (C++26 CD).

LWG4554 Remove undefined behaviour from hive for invalid limits

0dce0d5

Fixes NB US 139-232 (C++26 CD).

LWG4555 Remove is_consteval_only

979854d

Fixes NB US 81-149 (C++26 CD).

LWG4556 Unclear properties of reflection strings

d1cc2da

LWG4557 Remove constexpr from owner_less and owner_before

4c8da02

Fixes NB US 75-138 (C++26 CD).

tkoeppe force-pushed the motions-2026-03-lwg-2 branch from 5f316fe to 4c8da02 Compare April 18, 2026 00:10

tkoeppe merged commit 5a7a924 into main Apr 18, 2026
4 checks passed

	\tcode{\exposid{V}.data() +} \range{0}{\exposid{V}.size()}
	$\tcode{\exposid{V}.data()} + \crange{0}{\exposid{V}.size()}$

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burblebee commented Apr 9, 2026

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jwakely Apr 14, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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jwakely Apr 14, 2026 •

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