* [PATCH] libstdc++: Implement LWG 3481 change to ranges::viewable_range
@ 2021-10-20 16:59 Patrick Palka
2021-10-20 18:55 ` Jonathan Wakely
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2021-10-20 16:59 UTC (permalink / raw)
To: gcc-patches; +Cc: libstdc++, Patrick Palka
Tested on x86_64-pc-linux-gnu, does this look OK for trunk, and branches
after a while?
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] libstdc++: Implement LWG 3481 change to ranges::viewable_range
2021-10-20 16:59 [PATCH] libstdc++: Implement LWG 3481 change to ranges::viewable_range Patrick Palka
@ 2021-10-20 18:55 ` Jonathan Wakely
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Wakely @ 2021-10-20 18:55 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc Patches, libstdc++
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
>
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