[wip,nomerge,rfc] build: Require C++23 compiler #36033

pull maflcko wants to merge 9 commits into bitcoin:master from maflcko:2608-cpp23 changing 56 files +104 −410

maflcko commented at 9:06 AM on August 20, 2026: member
C++23 for Bitcoin Core is mostly a "style update" on top of C++20. However, the workarounds to avoid C++23 keep accumulating and some parts of the code already use C++23 features, such as lambda attributes (https://github.com/bitcoin-core/libmultiprocess/commit/bdd0cd69418d189f62699d274a751cbf6d36bb43).

I don't know when it is fine to switch, but at some point, I think it is fine to require a C++23 compiler, so that new stuff is unlocked. Of course this requires bumping the minimum required compiler versions:
- GCC: 13
- Clang: 19
There are some C++23 features that aren't implemented (such as <stacktrace> not really shipped in any vanilla stdlib today), or e.g. ranges::starts_with not implemented until libstdc++-16. But overall I think we are better off using C++23 without those few features instead of waiting longer?
DrahtBot renamed this:
~~[wip,nomerge,rfc] build: Require C++23 compiler~~
[wip,nomerge,rfc] build: Require C++23 compiler
on Aug 20, 2026
DrahtBot commented at 9:06 AM on August 20, 2026: contributor


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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/36033.



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Concept ACK l0rinc

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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #36255 (Refactor CoinGrinder tests by murchandamus)
- #36052 (ci: Doc: Move all config comments right next to the option they explain by maflcko)
- #35713 (Remove boost as a unit test runner by rustaceanrob)
- #34844 (util: Add util::NotNull<SmartPtrType> by maflcko)
- #34132 (coins, dbwrapper: remove error catcher, make point-read failures fatal by l0rinc)
If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.
maflcko marked this as a draft on Aug 20, 2026
maflcko force-pushed on Aug 20, 2026
DrahtBot added the label CI failed on Aug 20, 2026
DrahtBot commented at 10:17 AM on August 20, 2026: contributor


🚧 At least one of the CI tasks failed. <sub>Task NetBSD Cross: https://github.com/bitcoin/bitcoin/actions/runs/32352184973/job/96373551351</sub> <sub>LLM reason (✨ experimental): CI failed due to a C++ build error: std::ranges::views::zip is not available (no member named 'zip' in namespace 'std::ranges::views').</sub>

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:
- Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.
- A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.
- An intermittent issue.
Leave a comment here, if you need help tracking down a confusing failure.

</details>
maflcko force-pushed on Aug 21, 2026
l0rinc commented at 5:08 PM on August 21, 2026: contributor

Concept ACK
hebasto commented at 4:34 PM on August 23, 2026: member

edede385cab47020124bba6db98d69319168afb5

iwyu incorrectly suggests to remove the util/expected include

This looks like IWYU's "Automatic re-export: function return values" heuristics in action.
maflcko force-pushed on Aug 24, 2026
maflcko force-pushed on Aug 24, 2026
maflcko force-pushed on Aug 24, 2026
DrahtBot added the label Needs rebase on Sep 9, 2026
maflcko force-pushed on Sep 23, 2026
DrahtBot removed the label Needs rebase on Sep 23, 2026
maflcko force-pushed on Sep 23, 2026
DrahtBot added the label Needs rebase on Sep 29, 2026
build: Require C++23 compiler b5bb646ed6
util: Remove ALWAYS_FALSE type 5bafd3457f
compat: Use std::byteswap e15ba34a99

Type	Reviewers
Concept ACK	l0rinc

test: Adjust util::Expected tests for C++23

1) value() might be marked [[nodiscard]], so add the missing (void),
   where the value is ignored.

2) std::expected::value() must be able to throw
   std::bad_expected_access<E> if the expected contains an error. That
   requires copying the error type, which is not possible in this unit
   test that uses a non-copyable error type.

   Fix it by using the non-throwing value accessor.

5737327062

util: Use std::expected 9afe049e4d
test: Remove unused util::Expected tests cd248eb1a0
refactor: Use std::views::zip in btck import blocks 58bc45b0a9
maflcko force-pushed on Sep 30, 2026

refactor: Make iwyu happy

IWYU will now apply the
https://github.com/include-what-you-use/include-what-you-use/blob/master/docs/WhatIsAUse.md#automatic-re-export-function-return-values
heuristic.

4d10bcb431

refactor: clang-tidy readability-container-contains for C++23 8fcbeb84ce
maflcko force-pushed on Sep 30, 2026
DrahtBot removed the label Needs rebase on Sep 30, 2026

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#34979 build: Drop build support on vanilla Ubuntu Jammy 22.04 LTS?

[wip,nomerge,rfc] build: Require C++23 compiler #36033

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