diff --git a/libstdc++-v3/include/bits/stl_pair.h b/libstdc++-v3/include/bits/stl_pair.h index acd0c7b58f91d40974ecfe6997d7c9e76ed1f781..b81b479ad43abdefb91b943b77066594bb5a5023 100644 --- a/libstdc++-v3/include/bits/stl_pair.h +++ b/libstdc++-v3/include/bits/stl_pair.h @@ -404,6 +404,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION return false; } + template<typename _U1, typename _U2> + static constexpr bool + _S_const_assignable() + { + if constexpr (is_assignable_v<const _T1&, _U1>) + return is_assignable_v<const _T2&, _U2>; + return false; + } + template<typename _U1, typename _U2> static constexpr bool _S_nothrow_assignable() @@ -468,8 +477,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Copy assignment operator (const) constexpr const pair& operator=(const pair& __p) const - requires is_copy_assignable_v<const first_type> - && is_copy_assignable_v<const second_type> + requires (_S_const_assignable<const first_type&, const second_type&>()) { first = __p.first; second = __p.second; @@ -479,8 +487,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Move assignment operator (const) constexpr const pair& operator=(pair&& __p) const - requires is_assignable_v<const first_type&, first_type> - && is_assignable_v<const second_type&, second_type> + requires (_S_const_assignable<first_type, second_type>()) { first = std::forward<first_type>(__p.first); second = std::forward<second_type>(__p.second); @@ -491,8 +498,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _U1, typename _U2> constexpr const pair& operator=(const pair<_U1, _U2>& __p) const - requires is_assignable_v<const first_type&, const _U1&> - && is_assignable_v<const second_type&, const _U2&> + requires (_S_const_assignable<const _U1&, const _U2&>()) { first = __p.first; second = __p.second; @@ -503,8 +509,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _U1, typename _U2> constexpr const pair& operator=(pair<_U1, _U2>&& __p) const - requires is_assignable_v<const first_type&, _U1> - && is_assignable_v<const second_type&, _U2> + requires (_S_const_assignable<_U1, _U2>()) { first = std::forward<_U1>(__p.first); second = std::forward<_U2>(__p.second);