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Compilation failure with Clang 17 and `-std=cpp23`

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#137 2 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
cmake, cpp

Research direction

Extract the attached archive and run the documented cmake preset with Clang 17, GCC 14 and C++23 to reproduce the failure from boost/program_options.hpp. Compare the build with C++20, then inspect the program_options headers involved in the reported tuple/get diagnostic. Done means the reproduction compiles successfully under the reported C++23 configuration without requiring the workaround.

Written by the indexing model from the issue text.

Description

Summary

Including <boost/program_options.hpp> causes a compilation failure when compiling with clang 17.0.6 and GNU stdlibc++ 14 with -std=gnu++23

Steps to reproduce

Install boost (a conanfile is provided) and extract the attached archive.

boost-po-test.tar.gz

tar -xf boost-po-test-tgz
cd boost-po-test/
cmake --preset default
cmake --build build/default

Expected result

compilation is successful

Actual result

compilation fails with

/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/14.1.1/../../../../include/c++/14.1.1/tuple:956:36: error: no matching function for call to 'get'
  956 |             return __convertible<decltype(std::get<_Is>(std::declval<_UTuple>()))...>();

Workaround

Edit the CMakeLists.txt file and change

set(CMAKE_CXX_STANDARD 23)

to

set(CMAKE_CXX_STANDARD 20)

and recompile.

System Info

Boost 1.85.0 (conan)
Arch Linux
Clang 17.0.6
GCC 14.1.1

Dominant language
C++
Stars
136
Forks
117
PR merge metrics
No merged PRs in 30d

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