Title should say: Qualify
On Thu, Nov 12, 2026 at 5:28 PM Tomasz Kamiński <[email protected]> wrote:
> These functions are forward declared in bits/stl_pair.h and defining
> them using qualified name guarantees that signatures are matching.
>
> The deleted get<I>(const tuple<...>&) overloads for N > tuple_size is
> moved to
> bits/stl_pair.h, so the candidate set is the same regardless if tuple
> is included.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/stl_pair.h (std::get(const tuple<...>&)): Moved
> from...
> * include/std/tuple (std::get<_Int>): Move deleted overload for out
> of bounds index to bits/stl_pair.h. Qualify remaining definitions.
> * include/std/array (std::get<_Int>): Qualify definitions.
> * include/std/complex (std::get<_Int>): Qualify definitions.
> ---
> As discussed, this is worth doing as it would detect mismatches and
> prevent problesm like PR128657.
>
> Testing on x86_64 and powerpc64-le. OK for trunk when all tests
> passes?
>
> libstdc++-v3/include/bits/stl_pair.h | 16 +++++++++++-----
> libstdc++-v3/include/std/array | 8 ++++----
> libstdc++-v3/include/std/complex | 9 +++++----
> libstdc++-v3/include/std/tuple | 16 +++++-----------
> 4 files changed, 25 insertions(+), 24 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/stl_pair.h
> b/libstdc++-v3/include/bits/stl_pair.h
> index ccff8691206..645e394520c 100644
> --- a/libstdc++-v3/include/bits/stl_pair.h
> +++ b/libstdc++-v3/include/bits/stl_pair.h
> @@ -133,6 +133,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> constexpr const __tuple_element_t<__i, tuple<_Elements...>>&&
> get(const tuple<_Elements...>&& __t) noexcept;
>
> + /// @cond undocumented
> + // Deleted overload chosen for invalid indices.
> + template<size_t __i, typename... _Elements>
> + constexpr __enable_if_t<(__i >= sizeof...(_Elements))>
> + get(const tuple<_Elements...>&) = delete;
> + /// @endcond
> +
> template<size_t _Int, typename _Tp, size_t _Nm>
> constexpr _Tp&
> get(array<_Tp, _Nm>&) noexcept;
> @@ -1284,25 +1291,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
> template<size_t _Int, class _Tp1, class _Tp2>
> constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
> - get(pair<_Tp1, _Tp2>& __in) noexcept
> + ::std::get(pair<_Tp1, _Tp2>& __in) noexcept
> { return __pair_get<_Int>::__get(__in); }
>
> template<size_t _Int, class _Tp1, class _Tp2>
> constexpr typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
> - get(pair<_Tp1, _Tp2>&& __in) noexcept
> + ::std::get(pair<_Tp1, _Tp2>&& __in) noexcept
> { return __pair_get<_Int>::__move_get(std::move(__in)); }
>
> template<size_t _Int, class _Tp1, class _Tp2>
> constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&
> - get(const pair<_Tp1, _Tp2>& __in) noexcept
> + ::std::get(const pair<_Tp1, _Tp2>& __in) noexcept
> { return __pair_get<_Int>::__const_get(__in); }
>
> template<size_t _Int, class _Tp1, class _Tp2>
> constexpr const typename tuple_element<_Int, pair<_Tp1, _Tp2>>::type&&
> - get(const pair<_Tp1, _Tp2>&& __in) noexcept
> + ::std::get(const pair<_Tp1, _Tp2>&& __in) noexcept
> { return __pair_get<_Int>::__const_move_get(std::move(__in)); }
>
> -
> #ifdef __glibcxx_tuples_by_type // C++ >= 14
> template <typename _Tp, typename _Up>
> constexpr _Tp&
> diff --git a/libstdc++-v3/include/std/array
> b/libstdc++-v3/include/std/array
> index 5d3edbea649..77a3ce12154 100644
> --- a/libstdc++-v3/include/std/array
> +++ b/libstdc++-v3/include/std/array
> @@ -392,7 +392,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<std::size_t _Int, typename _Tp, std::size_t _Nm>
> [[__nodiscard__]]
> constexpr _Tp&
> - get(array<_Tp, _Nm>& __arr) noexcept
> + ::std::get(array<_Tp, _Nm>& __arr) noexcept
> {
> static_assert(_Int < _Nm, "array index is within bounds");
> return __arr._M_elems[_Int];
> @@ -401,7 +401,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<std::size_t _Int, typename _Tp, std::size_t _Nm>
> [[__nodiscard__]]
> constexpr _Tp&&
> - get(array<_Tp, _Nm>&& __arr) noexcept
> + ::std::get(array<_Tp, _Nm>&& __arr) noexcept
> {
> static_assert(_Int < _Nm, "array index is within bounds");
> return std::move(std::get<_Int>(__arr));
> @@ -410,7 +410,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<std::size_t _Int, typename _Tp, std::size_t _Nm>
> [[__nodiscard__]]
> constexpr const _Tp&
> - get(const array<_Tp, _Nm>& __arr) noexcept
> + ::std::get(const array<_Tp, _Nm>& __arr) noexcept
> {
> static_assert(_Int < _Nm, "array index is within bounds");
> return __arr._M_elems[_Int];
> @@ -419,7 +419,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<std::size_t _Int, typename _Tp, std::size_t _Nm>
> [[__nodiscard__]]
> constexpr const _Tp&&
> - get(const array<_Tp, _Nm>&& __arr) noexcept
> + ::std::get(const array<_Tp, _Nm>&& __arr) noexcept
> {
> static_assert(_Int < _Nm, "array index is within bounds");
> return std::move(std::get<_Int>(__arr));
> diff --git a/libstdc++-v3/include/std/complex
> b/libstdc++-v3/include/std/complex
> index 1be1c7abfb6..c1ea392af4c 100644
> --- a/libstdc++-v3/include/std/complex
> +++ b/libstdc++-v3/include/std/complex
> @@ -638,10 +638,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> #endif
>
> #if __glibcxx_tuple_like >= 202311L // >= C++26
> + // Forward declared in bits/stl_pair.h
> template<size_t _Int, typename _Tp>
> [[nodiscard,__gnu__::__always_inline__]]
> constexpr _Tp&
> - get(complex<_Tp>& __z) noexcept
> + ::std::get(complex<_Tp>& __z) noexcept
> {
> static_assert(_Int < 2);
> return __z.__get_part(_Int);
> @@ -650,7 +651,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<size_t _Int, typename _Tp>
> [[nodiscard,__gnu__::__always_inline__]]
> constexpr _Tp&&
> - get(complex<_Tp>&& __z) noexcept
> + ::std::get(complex<_Tp>&& __z) noexcept
> {
> static_assert(_Int < 2);
> return std::move(__z.__get_part(_Int));
> @@ -659,7 +660,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<size_t _Int, typename _Tp>
> [[nodiscard,__gnu__::__always_inline__]]
> constexpr const _Tp&
> - get(const complex<_Tp>& __z) noexcept
> + ::std::get(const complex<_Tp>& __z) noexcept
> {
> static_assert(_Int < 2);
> return __z.__get_part(_Int);
> @@ -668,7 +669,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> template<size_t _Int, typename _Tp>
> [[nodiscard,__gnu__::__always_inline__]]
> constexpr const _Tp&&
> - get(const complex<_Tp>&& __z) noexcept
> + ::std::get(const complex<_Tp>&& __z) noexcept
> {
> static_assert(_Int < 2);
> return std::move(__z.__get_part(_Int));
> diff --git a/libstdc++-v3/include/std/tuple
> b/libstdc++-v3/include/std/tuple
> index d73cefcbca8..4e28c3920b0 100644
> --- a/libstdc++-v3/include/std/tuple
> +++ b/libstdc++-v3/include/std/tuple
> @@ -2462,22 +2462,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> __enable_if_t<(__i >= sizeof...(_Types))>
> __get_helper(const tuple<_Types...>&) = delete;
>
> + // Declared in bits/stl_pair.h
> /// Return a reference to the ith element of a tuple.
> template<size_t __i, typename... _Elements>
> constexpr __tuple_element_t<__i, tuple<_Elements...>>&
> - get(tuple<_Elements...>& __t) noexcept
> + ::std::get(tuple<_Elements...>& __t) noexcept
> { return std::__get_helper<__i>(__t); }
>
> /// Return a const reference to the ith element of a const tuple.
> template<size_t __i, typename... _Elements>
> constexpr const __tuple_element_t<__i, tuple<_Elements...>>&
> - get(const tuple<_Elements...>& __t) noexcept
> + ::std::get(const tuple<_Elements...>& __t) noexcept
> { return std::__get_helper<__i>(__t); }
>
> /// Return an rvalue reference to the ith element of a tuple rvalue.
> template<size_t __i, typename... _Elements>
> constexpr __tuple_element_t<__i, tuple<_Elements...>>&&
> - get(tuple<_Elements...>&& __t) noexcept
> + ::std::get(tuple<_Elements...>&& __t) noexcept
> {
> typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
> return std::forward<__element_type>(std::__get_helper<__i>(__t));
> @@ -2486,19 +2487,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> /// Return a const rvalue reference to the ith element of a const tuple
> rvalue.
> template<size_t __i, typename... _Elements>
> constexpr const __tuple_element_t<__i, tuple<_Elements...>>&&
> - get(const tuple<_Elements...>&& __t) noexcept
> + ::std::get(const tuple<_Elements...>&& __t) noexcept
> {
> typedef __tuple_element_t<__i, tuple<_Elements...>> __element_type;
> return std::forward<const
> __element_type>(std::__get_helper<__i>(__t));
> }
>
> - /// @cond undocumented
> - // Deleted overload chosen for invalid indices.
> - template<size_t __i, typename... _Elements>
> - constexpr __enable_if_t<(__i >= sizeof...(_Elements))>
> - get(const tuple<_Elements...>&) = delete;
> - /// @endcond
> -
> #ifdef __cpp_lib_tuples_by_type // C++ >= 14
> /// Return a reference to the unique element of type _Tp of a tuple.
> template <typename _Tp, typename... _Types>
> --
> 2.56.1
>
>
