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* include/std/variant (__accepted_index): Use void_t.

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From-SVN: r262471
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Jonathan Wakely 2018-07-06 11:20:38 +01:00 • committed by Jonathan Wakely
parent f9ccb8c0af
commit 4d023b5bd4
2 changed files with 7 additions and 3 deletions
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4
libstdc++-v3/ChangeLog
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@ -1,3 +1,7 @@
2018-07-06 Jonathan Wakely <jwakely@redhat.com>
* include/std/variant (__accepted_index): Use void_t.
2018-07-05 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/85831

6
libstdc++-v3/include/std/variant
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@ -710,7 +710,8 @@ namespace __variant
};
// Helper for variant(_Tp&&) and variant::operator=(_Tp&&).
// __accepted_index maps the arbitrary _Tp to an alternative type in _Variant.
// __accepted_index maps an arbitrary _Tp to an alternative type in _Variant
// (or to variant_npos).
template<typename _Tp, typename _Variant, typename = void>
struct __accepted_index
{ static constexpr size_t value = variant_npos; };
@ -718,8 +719,7 @@ namespace __variant
template<typename _Tp, typename... _Types>
struct __accepted_index<
_Tp, variant<_Types...>,
decltype(__overload_set<_Types...>::_S_fun(std::declval<_Tp>()),
std::declval<void>())>
void_t<decltype(__overload_set<_Types...>::_S_fun(std::declval<_Tp>()))>>
{
static constexpr size_t value = sizeof...(_Types) - 1
- decltype(__overload_set<_Types...>::