diff options
| author | Jonathan Wakely <jwakely@redhat.com> | 2021-10-22 22:55:00 +0100 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2021-10-22 23:09:54 +0100 |
| commit | 0c1f737a485f05c591c94b50acfb416c45a4c916 (patch) | |
| tree | 463bf48d61f97dd80200b8d9c6bcba8a95f5551e /libstdc++-v3 | |
| parent | 030875c197e339542ddfcbad90cfc01263151bec (diff) | |
| download | gcc-0c1f737a485f05c591c94b50acfb416c45a4c916.tar.gz | |
libstdc++: Constrain std::make_any [PR102894]
std::make_any should be constrained so it can only be called if the
construction of the return value would be valid.
libstdc++-v3/ChangeLog:
PR libstdc++/102894
* include/std/any (make_any): Add SFINAE constraint.
* testsuite/20_util/any/102894.cc: New test.
Diffstat (limited to 'libstdc++-v3')
| -rw-r--r-- | libstdc++-v3/include/std/any | 13 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/20_util/any/102894.cc | 20 |
2 files changed, 29 insertions, 4 deletions
diff --git a/libstdc++-v3/include/std/any b/libstdc++-v3/include/std/any index 9c102a58b26..f75dddf6d92 100644 --- a/libstdc++-v3/include/std/any +++ b/libstdc++-v3/include/std/any @@ -428,16 +428,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION /// Exchange the states of two @c any objects. inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); } - /// Create an any holding a @c _Tp constructed from @c __args. + /// Create an `any` holding a `_Tp` constructed from `__args...`. template <typename _Tp, typename... _Args> - any make_any(_Args&&... __args) + inline + enable_if_t<is_constructible_v<any, in_place_type_t<_Tp>, _Args...>, any> + make_any(_Args&&... __args) { return any(in_place_type<_Tp>, std::forward<_Args>(__args)...); } - /// Create an any holding a @c _Tp constructed from @c __il and @c __args. + /// Create an `any` holding a `_Tp` constructed from `__il` and `__args...`. template <typename _Tp, typename _Up, typename... _Args> - any make_any(initializer_list<_Up> __il, _Args&&... __args) + inline + enable_if_t<is_constructible_v<any, in_place_type_t<_Tp>, + initializer_list<_Up>&, _Args...>, any> + make_any(initializer_list<_Up> __il, _Args&&... __args) { return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...); } diff --git a/libstdc++-v3/testsuite/20_util/any/102894.cc b/libstdc++-v3/testsuite/20_util/any/102894.cc new file mode 100644 index 00000000000..66ea9a03fea --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/any/102894.cc @@ -0,0 +1,20 @@ +// { dg-do compile { target c++17 } } +#include <any> + +template<typename T, typename = void> +struct can_make_any +: std::false_type +{ }; + +template<typename T> +struct can_make_any<T, std::void_t<decltype(std::make_any<T>())>> +: std::true_type +{ }; + +struct move_only +{ + move_only() = default; + move_only(move_only&&) = default; +}; + +static_assert( ! can_make_any<move_only>::value ); // PR libstdc++/102894 |