On Thu, 5 Jun 2025 at 16:21, Tomasz Kamiński <tkami...@redhat.com> wrote:
>
> When the static assert was generated from instantiations of default member
> initializer of class B, the error was not generated for B<1, std::layout_left,
> std::layout_left> case, only when -D_GLIBCXX_DEBUG was set. Changing B calls
> to
> functions fixes that.
>
> libstdc++-v3/ChangeLog:
>
> * include/std/mdspan (__mdspan::__mapping_alike): Rename template
> parameter from M to _M_p.
> (layout_stride::mapping): Fix typo in comment.
> * 23_containers/mdspan/layouts/class_mandate_neg.cc: Changed B to
> function.
OK for trunk
> ---
> This patch add minor fixes suggeted by Daniel. It also reworks a bit
> class_mandate_neg.cc test, as previously one error was not generated
> when debug was enabled.
>
> libstdc++-v3/include/std/mdspan | 18 +++++++++---------
> .../mdspan/layouts/class_mandate_neg.cc | 18 ++++++++++--------
> 2 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/libstdc++-v3/include/std/mdspan b/libstdc++-v3/include/std/mdspan
> index 4a3e863bed5..fbb85fe3f73 100644
> --- a/libstdc++-v3/include/std/mdspan
> +++ b/libstdc++-v3/include/std/mdspan
> @@ -780,16 +780,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
> namespace __mdspan
> {
> - template<typename M>
> + template<typename _Mp>
> concept __mapping_alike = requires
> {
> - requires __is_extents<typename M::extents_type>;
> - { M::is_always_strided() } -> same_as<bool>;
> - { M::is_always_exhaustive() } -> same_as<bool>;
> - { M::is_always_unique() } -> same_as<bool>;
> - bool_constant<M::is_always_strided()>::value;
> - bool_constant<M::is_always_exhaustive()>::value;
> - bool_constant<M::is_always_unique()>::value;
> + requires __is_extents<typename _Mp::extents_type>;
> + { _Mp::is_always_strided() } -> same_as<bool>;
> + { _Mp::is_always_exhaustive() } -> same_as<bool>;
> + { _Mp::is_always_unique() } -> same_as<bool>;
> + bool_constant<_Mp::is_always_strided()>::value;
> + bool_constant<_Mp::is_always_exhaustive()>::value;
> + bool_constant<_Mp::is_always_unique()>::value;
> };
>
> template<typename _Mapping>
> @@ -847,7 +847,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> mapping() noexcept
> {
> // The precondition is either statically asserted, or automatically
> - // satisfied because dynamic extents are zero-initialzied.
> + // satisfied because dynamic extents are zero-initialized.
> size_t __stride = 1;
> for (size_t __i = extents_type::rank(); __i > 0; --__i)
> {
> diff --git
> a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
> b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
> index 70a25707cb2..7091153daba 100644
> --- a/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
> +++ b/libstdc++-v3/testsuite/23_containers/mdspan/layouts/class_mandate_neg.cc
> @@ -18,7 +18,8 @@ template<typename Layout>
> };
>
> template<size_t Count, typename Layout, typename OLayout>
> - struct B
> + bool
> + B()
> {
> using Extents = std::extents<uint8_t, dyn, dyn, Count>;
> using OExtents = std::extents<uint16_t, n, 4, Count>;
> @@ -27,20 +28,21 @@ template<size_t Count, typename Layout, typename OLayout>
> using OMapping = typename OLayout::mapping<OExtents>;
>
> Mapping m{OMapping{}};
> + return true;
> };
>
> A<std::layout_left> a_left; // { dg-error "required
> from" }
> A<std::layout_right> a_right; // { dg-error "required
> from" }
> A<std::layout_stride> a_stride; // { dg-error "required
> from" }
>
> -B<1, std::layout_left, std::layout_left> b0; // { dg-error "required
> here" }
> -B<2, std::layout_left, std::layout_stride> b1; // { dg-error "required
> here" }
> +auto b1 = B<1, std::layout_left, std::layout_left>(); // { dg-error
> "required from" }
> +auto b2 = B<2, std::layout_left, std::layout_stride>(); // { dg-error
> "required from" }
>
> -B<3, std::layout_right, std::layout_right> b2; // { dg-error "required
> here" }
> -B<4, std::layout_right, std::layout_stride> b3; // { dg-error "required
> here" }
> +auto b3 = B<3, std::layout_right, std::layout_right>(); // { dg-error
> "required from" }
> +auto b4 = B<4, std::layout_right, std::layout_stride>(); // { dg-error
> "required from" }
>
> -B<5, std::layout_stride, std::layout_right> b4; // { dg-error "required
> here" }
> -B<6, std::layout_stride, std::layout_left> b5; // { dg-error "required
> here" }
> -B<7, std::layout_stride, std::layout_stride> b6; // { dg-error "required
> here" }
> +auto b5 = B<5, std::layout_stride, std::layout_right>(); // { dg-error
> "required from" }
> +auto b6 = B<6, std::layout_stride, std::layout_left>(); // { dg-error
> "required from" }
> +auto b7 = B<7, std::layout_stride, std::layout_stride>(); // { dg-error
> "required from" }
>
> // { dg-prune-output "must be representable as index_type" }
> --
> 2.49.0
>
