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| author | Jonathan Wakely <jwakely@redhat.com> | 2022-01-11 14:11:46 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2022-01-11 15:17:26 +0000 |
| commit | d2dc5305d87f4e6a1b861f59164c124636e2b69d (patch) | |
| tree | 15021ef10a5aaa736543f8db0ffce8b90a8b21db | |
| parent | 06bc1b0c539e3a60692d7432d15e701c38610f80 (diff) | |
| download | gcc-d2dc5305d87f4e6a1b861f59164c124636e2b69d.zip gcc-d2dc5305d87f4e6a1b861f59164c124636e2b69d.tar.gz gcc-d2dc5305d87f4e6a1b861f59164c124636e2b69d.tar.bz2 | |
libstdc++: Make copyable-box completely constexpr (LWG 3572)
This LWG issue was approved at the October 2021 plenary and can be
implemented now that std::optional is fully constexpr.
libstdc++-v3/ChangeLog:
* include/std/ranges (ranges::__detail::__box): Add constexpr to
assignment operators (LWG 3572).
* testsuite/std/ranges/adaptors/filter.cc: Check assignment of a
view that uses copyable-box.
| -rw-r--r-- | libstdc++-v3/include/std/ranges | 5 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc | 28 |
2 files changed, 31 insertions, 2 deletions
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index c90d33c..780a363 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -109,7 +109,8 @@ namespace ranges // _GLIBCXX_RESOLVE_LIB_DEFECTS // 3477. Simplify constraints for semiregular-box - __box& + // 3572. copyable-box should be fully constexpr + constexpr __box& operator=(const __box& __that) noexcept(is_nothrow_copy_constructible_v<_Tp>) requires (!copyable<_Tp>) @@ -124,7 +125,7 @@ namespace ranges return *this; } - __box& + constexpr __box& operator=(__box&& __that) noexcept(is_nothrow_move_constructible_v<_Tp>) requires (!movable<_Tp>) diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc index b8d081e..ed5a01c 100644 --- a/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/filter.cc @@ -140,6 +140,33 @@ test06() static_assert(!requires { views::all | filter; }); } +constexpr bool +test07() +{ + struct Pred + { + constexpr Pred() { } + constexpr Pred(const Pred&) { } + constexpr Pred(Pred&&) { } + // These make it non-copyable, so non-copyable-box<Pred> will provide + // assignment. + Pred& operator=(const Pred&) = delete; + Pred& operator=(Pred&&) = delete; + + bool operator()(int i) const { return i < 10; } + }; + + int i = 0; + ranges::filter_view v(views::single(i), Pred{}); + // LWG 3572. copyable-box should be fully constexpr + v = v; + v = std::move(v); + + return true; +} + +static_assert( test07() ); + int main() { @@ -150,4 +177,5 @@ main() test05<forward_iterator_wrapper>(); test05<random_access_iterator_wrapper>(); test06(); + test07(); } |