public inbox for gcc-cvs@sourceware.org help / color / mirror / Atom feed
From: Jonathan Wakely <redi@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-9293] libstdc++: Constrain std::make_any [PR102894] Date: Wed, 24 Nov 2021 11:51:38 +0000 (GMT) [thread overview] Message-ID: <20211124115138.956AC3857C7A@sourceware.org> (raw) https://gcc.gnu.org/g:88d481c9ee1e6a24dc11ab56d8688308e0211855 commit r11-9293-g88d481c9ee1e6a24dc11ab56d8688308e0211855 Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Oct 22 22:55:00 2021 +0100 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. (cherry picked from commit 0c1f737a485f05c591c94b50acfb416c45a4c916) Diff: --- libstdc++-v3/include/std/any | 13 +++++++++---- 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 a6995b79c43..5e2fb145441 100644 --- a/libstdc++-v3/include/std/any +++ b/libstdc++-v3/include/std/any @@ -421,16 +421,21 @@ _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
reply other threads:[~2021-11-24 11:51 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20211124115138.956AC3857C7A@sourceware.org \ --to=redi@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ --cc=libstdc++-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).