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disable clang warning about pack indexing in C++20 #1600

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Merged
merged 1 commit into from
Jul 31, 2025
Merged

disable clang warning about pack indexing in C++20 #1600

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9 changes: 9 additions & 0 deletions include/stdexec/__detail/__config.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -398,6 +398,15 @@ namespace stdexec {
# define STDEXEC_TERMINATE() std::terminate()
#endif

// Some compilers turn on pack indexing in pre-C++26 code. We want to use it if it is
// available. Pack indexing is disabled for clang < 20 because of:
// https://github.com/llvm/llvm-project/issues/116105
#if defined(__cpp_pack_indexing) && !STDEXEC_NVCC() && !(STDEXEC_CLANG() && __clang_major__ < 20)
# define STDEXEC_HAS_PACK_INDEXING() 1
#else // ^^^ has pack indexing ^^^ / vvv no pack indexing vvv
# define STDEXEC_HAS_PACK_INDEXING() 0
#endif // no pack indexing

#if STDEXEC_HAS_FEATURE(thread_sanitizer) || defined(__SANITIZE_THREAD__)
# define STDEXEC_TSAN(...) STDEXEC_HEAD_OR_TAIL(1, __VA_ARGS__)
#else
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9 changes: 6 additions & 3 deletions include/stdexec/__detail/__meta.hpp
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Expand Up @@ -1025,9 +1025,10 @@ namespace stdexec {
using __f = __mor<__minvoke<_Fn, _Args>...>;
};

// C++23 pack indexing is disabled for clang because of
// https://github.com/llvm/llvm-project/issues/116105
#if defined(__cpp_pack_indexing) && !STDEXEC_CLANG()
#if STDEXEC_HAS_PACK_INDEXING()
STDEXEC_PRAGMA_PUSH()
STDEXEC_PRAGMA_IGNORE_GNU("-Wc++26-extensions")

template <bool>
struct __m_at_ {
template <class _Np, class... _Ts>
Expand All @@ -1039,6 +1040,8 @@ namespace stdexec {

template <std::size_t _Np, class... _Ts>
using __m_at_c = __minvoke<__m_at_<_Np == ~0ul>, __msize_t<_Np>, _Ts...>;

STDEXEC_PRAGMA_POP()
#elif STDEXEC_HAS_BUILTIN(__type_pack_element)
template <bool>
struct __m_at_ {
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