public inbox for libstdc++-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 r11-10133] libstdc++: Make ranges::size and ranges::empty check for unbounded arrays Date: Thu, 7 Jul 2022 23:33:31 +0000 (GMT) [thread overview] Message-ID: <20220707233331.1266B384B0F7@sourceware.org> (raw) https://gcc.gnu.org/g:c8f091982c748a8a180e9e2b24740f9a388f63da commit r11-10133-gc8f091982c748a8a180e9e2b24740f9a388f63da Author: Jonathan Wakely <jwakely@redhat.com> Date: Sun Dec 12 21:16:25 2021 +0000 libstdc++: Make ranges::size and ranges::empty check for unbounded arrays Passing IncompleteType(&)[] to ranges::begin produces an error outside the immediate context, which is fine for ranges::begin, but it means that we fail to enforce the SFINAE-able constraints for ranges::size and ranges::size. They should not be callable for any array of unknown bound, whether the type is complete or not. Because we don't enforce that in their constraints, we get a hard error when they try to use ranges::begin. This simply adds explicit checks for arrays of unknown bound to the constraints for ranges::size and ranges::empty. We only need to check it for the __sentinel_size and __eq_iter_empty concepts, because those are the ones that are relevant to arrays, and which try to use ranges::begin. libstdc++-v3/ChangeLog: * include/bits/ranges_base.h (ranges::size, ranges::empty): Add explicit check for unbounded arrays before using ranges::begin. * testsuite/std/ranges/access/empty.cc: Check handling of unbounded arrays. * testsuite/std/ranges/access/size.cc: Likewise. (cherry picked from commit 55823c5a0ba50022d7fcc95e74ec293143810ef6) Diff: --- libstdc++-v3/include/bits/ranges_base.h | 4 ++++ libstdc++-v3/testsuite/std/ranges/access/empty.cc | 10 ++++++++++ libstdc++-v3/testsuite/std/ranges/access/size.cc | 10 ++++++++++ 3 files changed, 24 insertions(+) diff --git a/libstdc++-v3/include/bits/ranges_base.h b/libstdc++-v3/include/bits/ranges_base.h index 6d2d5bf939d..2a525e421b9 100644 --- a/libstdc++-v3/include/bits/ranges_base.h +++ b/libstdc++-v3/include/bits/ranges_base.h @@ -379,6 +379,8 @@ namespace ranges template<typename _Tp> concept __sentinel_size = requires(_Tp& __t) { + requires (!is_unbounded_array_v<remove_reference_t<_Tp>>); + { _Begin{}(__t) } -> forward_iterator; { _End{}(__t) } -> sized_sentinel_for<decltype(_Begin{}(__t))>; @@ -462,6 +464,8 @@ namespace ranges template<typename _Tp> concept __eq_iter_empty = requires(_Tp& __t) { + requires (!is_unbounded_array_v<remove_reference_t<_Tp>>); + { _Begin{}(__t) } -> forward_iterator; bool(_Begin{}(__t) == _End{}(__t)); diff --git a/libstdc++-v3/testsuite/std/ranges/access/empty.cc b/libstdc++-v3/testsuite/std/ranges/access/empty.cc index b2d8b105325..693355c6cf5 100644 --- a/libstdc++-v3/testsuite/std/ranges/access/empty.cc +++ b/libstdc++-v3/testsuite/std/ranges/access/empty.cc @@ -119,6 +119,16 @@ test04() static_assert( ! noexcept(std::ranges::empty(E3{})) ); } +template<typename T> + concept has_empty = requires (T& t) { std::ranges::empty(t); }; + +// If T is an array of unknown bound, ranges::empty(E) is ill-formed. +static_assert( ! has_empty<int[]> ); +static_assert( ! has_empty<int(&)[]> ); +static_assert( ! has_empty<int[][2]> ); +struct Incomplete; +static_assert( ! has_empty<Incomplete[]> ); + int main() { diff --git a/libstdc++-v3/testsuite/std/ranges/access/size.cc b/libstdc++-v3/testsuite/std/ranges/access/size.cc index f25a1cb9ddb..db843cddccb 100644 --- a/libstdc++-v3/testsuite/std/ranges/access/size.cc +++ b/libstdc++-v3/testsuite/std/ranges/access/size.cc @@ -120,6 +120,16 @@ test06() static_assert( std::ranges::size(R{}) == 42 ); } +template<typename T> + concept has_size = requires (T& t) { std::ranges::size(t); }; + +// If T is an array of unknown bound, ranges::size(E) is ill-formed. +static_assert( ! has_size<int[]> ); +static_assert( ! has_size<int(&)[]> ); +static_assert( ! has_size<int[][2]> ); +struct Incomplete; +static_assert( ! has_size<Incomplete[]> ); + int main() {
reply other threads:[~2022-07-07 23:33 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=20220707233331.1266B384B0F7@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).