https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121061
Tomasz Kamiński <tkaminsk at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2025-07-14
--- Comment #2 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
Related to above, the following is ill-formed:
```
class IntLike
{
public:
explicit
IntLike(int i)
: _M_i(i)
{ }
constexpr
operator int() && noexcept
{ return _M_i; }
private:
int _M_i;
};
IntLike il(1);
static_assert(std::is_constructible_v<std::extents<int, std::dynamic_extent>,
IntLike>);
std::extents<int, std::dynamic_extent> e1(std::move(il));
```
See: https://godbolt.org/z/hnd6zbde5
This is because, we do not move the index in constructor:
template<__mdspan::__valid_index_type<index_type>... _OIndexTypes>
requires (sizeof...(_OIndexTypes) == rank()
|| sizeof...(_OIndexTypes) == rank_dynamic())
constexpr explicit extents(_OIndexTypes... __exts) noexcept
: _M_exts(span<const _IndexType, sizeof...(_OIndexTypes)>(
initializer_list{_S_storage::_S_int_cast(__exts)...}))
{ }
`__exts` should be moved here, and _S_int_cast needs to be changed to be
forwarding.
This affects also operators() and mdspan/extents constructors.
