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

pull maflcko wants to merge 6 commits into bitcoin:master from maflcko:2608-cpp23 changing 12 files +39 −214

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 carve-outs 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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Possible places where comparison-specific test macros should replace generic comparisons:
- [src/test/util_expected_tests.cpp] BOOST_CHECK_THROW((void)e.value(), std::bad_expected_access<std::string>); and BOOST_CHECK_THROW(void_e.value(), std::bad_expected_access<std::string>); -> Consider BOOST_CHECK_EXCEPTION with a predicate that validates the exception details/message, instead of only checking the generic exception type.
2026-08-20 10:17:10
maflcko marked this as a draft on Aug 20, 2026
build: Require C++23 compiler 4fc30cb8b3
util: Remove ALWAYS_FALSE type a7fb64accb
compat: Use std::byteswap 42a10877b5

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.

c665e6c60c

util: Use std::expected c5f4ccf455
refactor: Use std::views::zip in btck import blocks d43cdbae8e
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. Task NetBSD Cross: https://github.com/bitcoin/bitcoin/actions/runs/32352184973/job/96373551351 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').

<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>

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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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