P3355R1 Fix submdspan for C++26

Author: tkoeppe

source/containers.tex

@@ -24319,6 +24319,19 @@
 let \tcode{offset} be a value of type \tcode{size_t} equal to
 \tcode{(*this)(\exposid{first_}<index_type, P>(slices...)...)}.
 
+\pnum
+Given a layout mapping type \tcode{M}, a type \tcode{S} is a
+\defnadjx{unit-stride}{slice for \tcode{M}}{slice} if
+\begin{itemize}
+\item \tcode{S} is a specialization of \tcode{strided_slice}
+where \tcode{S::stride_type} models \exposconcept{integral-constant-like}
+and \tcode{S::stride_type::value} equals \tcode{1},
+
+\item \tcode{S} models \tcode{\exposconcept{index-pair-like}<M::index_type>}, or
+
+\item \tcode{is_convertible_v<S, full_extent_t>} is \tcode{true}.
+\end{itemize}
+
 \rSec5[mdspan.sub.map.left]{\tcode{layout_left} specialization of \tcode{submdspan_mapping}}
 
 \indexlibrarymemberexpos{layout_left::mapping}{submdspan-mapping-impl}%

source/support.tex

@@ -797,7 +797,7 @@
 #define @\defnlibxname{cpp_lib_string_resize_and_overwrite}@       202110L // also in \libheader{string}
 #define @\defnlibxname{cpp_lib_string_udls}@                       201304L // also in \libheader{string}
 #define @\defnlibxname{cpp_lib_string_view}@                       202403L // also in \libheader{string}, \libheader{string_view}
-#define @\defnlibxname{cpp_lib_submdspan}@                         202403L // freestanding, also in \libheader{mdspan}
+#define @\defnlibxname{cpp_lib_submdspan}@                         202411L // freestanding, also in \libheader{mdspan}
 #define @\defnlibxname{cpp_lib_syncbuf}@                           201803L // also in \libheader{syncstream}
 #define @\defnlibxname{cpp_lib_text_encoding}@                     202306L // also in \libheader{text_encoding}
 #define @\defnlibxname{cpp_lib_three_way_comparison}@              201907L // freestanding, also in \libheader{compare}