Proposed resolution:

This wording is relative to N5008.

1. Modify [mdspan.layout.stride.obs] as indicated:

   constexpr bool is_exhaustive() const noexcept;
   

   -5- Returns: required_span_size() == extents().fwd-prod-of-extents(rank_).

   1. (5.1) — `true` if rank_ or the size of the multidimensional index space `m.extents()` is `0`.

   2. (5.2) — Otherwise, true if there is a permutation P of the integers in the range [0, rank_) such that stride(p₀) equals 1, and stride(p_i) equals stride(p_i−1) * extents().extent(p_i−1) for i in the range [1, rank_), where p_i is the i^th element of P.

   3. (5.3) — Otherwise, false.

[ Brno 2026-06-11; Change status: New → Ready. ]

[ 2026-06-10; Tomasz provides new wording ]

Reflect implementation in the wording.

[ 2026-05-29; Reflector poll. ]

Set priority to 3 after reflector poll.

Consider

constexpr std::extents ext{2, 1, 2};
constexpr std::array stride{1, 5, 2};
constexpr std::layout_stride::mapping lsm(ext, stride);

static_assert(lsm.is_exhaustive());

Implementations disagree on the result of `lsm.is_exhaustive()`: `true` on libstdc++ and libc++, `false` on MSVC STL.

github.com/microsoft/STL/#5477 claims that the mapping is exhaustive in this case, but [mdspan.layout.stride.obs]/6.2 requires this function to return `false`.

Should `is_exhaustive` be made to return `true` in this case (which is more correct and also easier to implement)?