C++ Standard Library Issues List (Revision D127)

Index by Section

Reference ISO/IEC IS 14882:2024(E)

This document is the Index by Section for the Library Active Issues List, Library Defect Reports and Accepted Issues, and Library Closed Issues List.

Index by Section

(view only non-Ready open issues)

Revised 2026-09-14 at 09:14:27 UTC

Section 16 (3 issues)

(view only non-Ready open issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
2136⁽ⁱ⁾	Ready	16.3.2 [structure]	Postconditions vs. exceptions	Yes	3
4586⁽ⁱ⁾	Ready	16.3.3.7 [freestanding.item]	Partial specialization of `std::format_kind` for `std::optional` is not marked hosted	Yes
4598⁽ⁱ⁾	Tentatively Ready	16.4.6.14 [res.on.exception.handling]	§[res.on.exception.handling] should cover exceptions specified outside a Throws: paragraph	Yes

Section 17 (2 issues)

(view only non-Ready open issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4605⁽ⁱ⁾	Tentatively Ready	17.3.2 [version.syn]	Feature test macro for `error_code` formatting	Yes
3584⁽ⁱ⁾	Ready	17.12.3 [cmp.common]	Clarify common comparison category conversions	Yes	3

Section 19 (1 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
3053⁽ⁱ⁾	Ready	19.5.4.1 [syserr.errcode.overview]	Prohibit `error_code` construction from rvalues of `error_category`	Yes	3

Section 20 (1 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4110⁽ⁱ⁾	Ready	20.4.2.2.2 [util.smartptr.shared.const]	`shared_ptr(nullptr_t, Deleter)` is overconstrained, breaking some sensible deleters	Yes	3

Section 21 (3 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4138⁽ⁱ⁾	Ready	21.3.11 [meta.const.eval]	`is_within_lifetime` should mandate `is_object`	Yes	3
4591⁽ⁱ⁾	Ready	21.4.8 [meta.reflection.scope]	`std::meta::current_function` should probably work in a local class	Yes	2
4576⁽ⁱ⁾	Ready	21.4.15 [meta.reflection.substitute]	`{can_}substitute` specification is (still) ill-formed	Yes	2

Section 22 (4 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
2811⁽ⁱ⁾	Ready	22.5.3.2 [optional.ctor]	"Selected constructor" wording is incorrect for `optional`/`variant`/`any`	Yes	3
4406⁽ⁱ⁾	Ready	22.5.3.7 [optional.observe]	`optional::value_or` return statement is inconsistent with Mandates	Yes	3
4367⁽ⁱ⁾	Ready	22.5.4.7 [optional.ref.monadic]	Improve `optional<T&>::or_else`	Yes	4
3991⁽ⁱ⁾	Ready	22.6.3.4 [variant.assign]	`variant`'s move assignment should not be guaranteed to produce a valueless by exception state	Yes	3

Section 23 (8 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4159⁽ⁱ⁾	Ready	23.2.5 [container.node]	Uses-allocator construction mechanisms should be opted out for node handles	Yes	3
2713⁽ⁱ⁾	Ready	23.5 [unord]	More missing allocator-extended constructors for unordered containers	Yes	3
4587⁽ⁱ⁾	Ready	23.5.3.3 [unord.map.elem]	Missing complexity for `unordered_map::at`	Yes
4397⁽ⁱ⁾	Ready	23.7.2.2.2 [span.cons]	Improve `span(R&& r)`	Yes	3
4606⁽ⁱ⁾	Ready	23.7.3.4.7.3 [mdspan.layout.stride.cons]	Bullet (4.3) preconditions are too strict to implement `submdspan`	Yes
4603⁽ⁱ⁾	Ready	23.7.3.4.7.3 [mdspan.layout.stride.cons]	`layout_stride` should accept zero strides for empty `extents`	Yes	3
4562⁽ⁱ⁾	Ready	23.7.3.4.7.4 [mdspan.layout.stride.obs]	`layout_stride::is_exhaustive` specification is problematic when there's an extent equal to 1	Yes	3
4588⁽ⁱ⁾	Ready	23.7.3.7.1 [mdspan.sub.overview]	`mdspan` issue due to rewording for canonicalize slice	Yes

Section 24 (3 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4546⁽ⁱ⁾	Ready	24.3.4.4 [iterator.concept.winc]	Integer-class type should be structural type	Yes	3
4055⁽ⁱ⁾	Ready	24.4.3 [iterator.operations]	§[iterator.operations] `std::distance` is missing a precondition	Yes	4
2595⁽ⁱ⁾	Ready	24.5.1.2 [reverse.iterator]	`reverse_iterator::operator[]`'s return type revisited	Yes	3

Section 25 (4 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
3985⁽ⁱ⁾	Ready	25.5.7.2 [range.utility.conv.to]	`ranges::to` should Mandates `C` not to be view	Yes	3
3832⁽ⁱ⁾	Ready	25.7.23.3 [range.elements.iterator]	Missing change for `element_view::iterator` in LWG 3798	Yes	3
4116⁽ⁱ⁾	Ready	25.7.24.3 [range.enumerate.iterator]	`enumerate_view::iterator` and `cartesian_product_view::iterator` should not always provide `iterator_category`	Yes	3
4117⁽ⁱ⁾	Ready	25.8.6 [coro.generator.iterator]	`generator::iterator` should provide `iterator_concept`	Yes	4

Section 26 (5 issues)

(view only non-Ready open issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4614⁽ⁱ⁾	Ready	26.10.16 [numeric.ops.midpoint]	§[numeric.ops.midpoint] No handling of non-finite floats	Yes	3
4593⁽ⁱ⁾	Tentatively Ready	26.10.17.2 [numeric.sat.cast]	The first template argument of `std::saturating_cast` must be specifiable	Yes
3628⁽ⁱ⁾	Ready	26.11 [specialized.algorithms]	"Effects: Equivalent to:" and uninitialized memory algorithms	Yes	3
3647⁽ⁱ⁾	Ready	26.11.2 [special.mem.concepts]	`nothrow-input-iterator` constraints should not mention copying	Yes	3
3889⁽ⁱ⁾	Ready	26.11.9 [specialized.destroy]	`std::(ranges::)destroy_at` should destroy array elements in the decreasing index order	Yes	3

Section 28 (8 issues)

(view only non-Ready open issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4602⁽ⁱ⁾	Ready	28.2.2 [charconv.to.chars]	Incorrect lower bound for the default floating-point representation	Yes	1
4421⁽ⁱ⁾	Ready	28.2.2 [charconv.to.chars]	Clarify the output encoding of `to_chars` for integers	Yes	3
3353⁽ⁱ⁾	Ready	28.3.3.1 [locale]	`locale`'s copy assignment operator should return `locale&`	Yes	3
4592⁽ⁱ⁾	Tentatively Ready	28.3.4.2.5.3 [locale.codecvt.virtuals]	Preconditions of some virtual functions `std::codecvt` on character ranges are in a possibly unintended form	Yes
2983⁽ⁱ⁾	Ready	28.3.4.7.3.3 [locale.money.put.virtuals]	`money_put::do_put` underspecified	Yes	3
2137⁽ⁱ⁾	Ready	28.6.7.3 [re.regex.assign]	Misleadingly constrained post-condition in the presence of exceptions	Yes	3
3126⁽ⁱ⁾	Ready	28.6.8 [re.submatch]	There's no `std::sub_match::compare(string_view)` overload	Yes	3
2220⁽ⁱ⁾	Ready	28.6.11.2.3 [re.tokiter.comp]	Under-specification of `operator==` for `regex_token_iterator`	Yes	3

Section 29 (3 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
2714⁽ⁱ⁾	Ready	29.4.6 [complex.ops]	`complex` stream extraction underspecified	Yes	3
3172⁽ⁱ⁾	Ready	29.7.3 [c.math.hypot3]	3-arg `std::hypot` is underspecified compared to the 2-arg overload	Yes	3
4601⁽ⁱ⁾	Ready	29.7.4 [c.math.lerp]	Unclear error handling for C++ math functions	Yes	3

Section 30 (2 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
2592⁽ⁱ⁾	Ready	30.2 [time.syn]	Require that `chrono::duration_cast`s from smaller durations to larger durations do not overflow	Yes	4
4022⁽ⁱ⁾	Ready	30.12 [time.format]	Ambiguity in the formatting of negative years with format specifier `%C`	Yes	3

Section 31 (2 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
3696⁽ⁱ⁾	Ready	31.2.2 [stream.types]	"Basic integral types" should not be used	Yes	3
4039⁽ⁱ⁾	Ready	31.7.6.3.5 [ostream.formatted.print]	§[ostream.formatted.print]: Inappropriate usage of `badbit` in definition of `vprint_unicode`/`vprint_nonunicode`	Yes	4

Section 32 (3 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
2819⁽ⁱ⁾	Ready	32.2.5 [thread.req.lockable]	Unspecified Return type: elements	Yes	3
3047⁽ⁱ⁾	Ready	32.5.8.3 [atomics.types.int]	`atomic` compound assignment operators can cause undefined behavior when corresponding `fetch_meow` members don't	Yes	3
3898⁽ⁱ⁾	Ready	32.9.3.3 [thread.barrier.class]	Possibly unintended preconditions for completion functions of `std::barrier`	Yes	3

Section 33 (2 issues)

Issue	Status	Section	Title	Proposed Resolution	Priority	Duplicates
4357⁽ⁱ⁾	Ready	33.9.10 [exec.connect]	`connect-awaitable` should use `is_void_v` to check for result-type of `co_await` expression instead of `same_as<void>`	Yes	4
4547⁽ⁱ⁾	Ready	33.13.1 [exec.as.awaitable]	`sender-awaitable` needs a deduction guide	Yes	2