| Message ID | 20211020165927.1827031-1-ppalka@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | libstdc++: Implement LWG 3481 change to ranges::viewable_range | expand |
On Wed, 20 Oct 2021 at 18:01, Patrick Palka wrote: > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk, and branches > after a while? Yes for all. > > libstdc++-v3/ChangeLog: > > * include/bits/ranges_base.h (viewable_range): Adjust as per > LWG 3481. > * testsuite/std/ranges/adaptors/all.cc (test07): New test. > --- > libstdc++-v3/include/bits/ranges_base.h | 3 ++- > libstdc++-v3/testsuite/std/ranges/adaptors/all.cc | 15 +++++++++++++++ > 2 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/libstdc++-v3/include/bits/ranges_base.h b/libstdc++-v3/include/bits/ranges_base.h > index 7801b2fd023..43b0b9f7bf3 100644 > --- a/libstdc++-v3/include/bits/ranges_base.h > +++ b/libstdc++-v3/include/bits/ranges_base.h > @@ -688,7 +688,8 @@ namespace ranges > /// A range which can be safely converted to a view. > template<typename _Tp> > concept viewable_range = range<_Tp> > - && (borrowed_range<_Tp> || view<remove_cvref_t<_Tp>>); > + && ((view<remove_cvref_t<_Tp>> && constructible_from<remove_cvref_t<_Tp>, _Tp>) > + || (!view<remove_cvref_t<_Tp>> && borrowed_range<_Tp>)); > > // [range.iter.ops] range iterator operations > > diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc > index 9a6a31e6cb4..ce1384c2890 100644 > --- a/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc > +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc > @@ -159,6 +159,20 @@ test06() > static_assert(!noexcept(views::all(BorrowedRange<false, false>(x)))); > } > > +void > +test07() > +{ > + // LWG 3481 > + struct view_t : ranges::empty_view<int> { // move-only view > + view_t(const view_t&) = delete; > + view_t(view_t&&) = default; > + view_t& operator=(const view_t&) = delete; > + view_t& operator=(view_t&&) = default; > + }; > + static_assert(std::movable<view_t> && !std::copyable<view_t>); > + static_assert(!ranges::viewable_range<view_t&>); > +} > + > int > main() > { > @@ -168,4 +182,5 @@ main() > static_assert(test04()); > test05(); > test06(); > + test07(); > } > -- > 2.33.1.711.g9d530dc002 >
diff --git a/libstdc++-v3/include/bits/ranges_base.h b/libstdc++-v3/include/bits/ranges_base.h index 7801b2fd023..43b0b9f7bf3 100644 --- a/libstdc++-v3/include/bits/ranges_base.h +++ b/libstdc++-v3/include/bits/ranges_base.h @@ -688,7 +688,8 @@ namespace ranges /// A range which can be safely converted to a view. template<typename _Tp> concept viewable_range = range<_Tp> - && (borrowed_range<_Tp> || view<remove_cvref_t<_Tp>>); + && ((view<remove_cvref_t<_Tp>> && constructible_from<remove_cvref_t<_Tp>, _Tp>) + || (!view<remove_cvref_t<_Tp>> && borrowed_range<_Tp>)); // [range.iter.ops] range iterator operations diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc index 9a6a31e6cb4..ce1384c2890 100644 --- a/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc +++ b/libstdc++-v3/testsuite/std/ranges/adaptors/all.cc @@ -159,6 +159,20 @@ test06() static_assert(!noexcept(views::all(BorrowedRange<false, false>(x)))); } +void +test07() +{ + // LWG 3481 + struct view_t : ranges::empty_view<int> { // move-only view + view_t(const view_t&) = delete; + view_t(view_t&&) = default; + view_t& operator=(const view_t&) = delete; + view_t& operator=(view_t&&) = default; + }; + static_assert(std::movable<view_t> && !std::copyable<view_t>); + static_assert(!ranges::viewable_range<view_t&>); +} + int main() { @@ -168,4 +182,5 @@ main() static_assert(test04()); test05(); test06(); + test07(); }