From 09b3018a2a17b92b4e4040c24bc56b73a5489cb6 Mon Sep 17 00:00:00 2001
From: Jakub Mazurkiewicz <mazkuba3@gmail.com>
Date: Wed, 5 Apr 2023 00:03:05 +0200
Subject: [PATCH 1/2] Fix `extents` deduction guide

---
 stl/inc/mdspan | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/stl/inc/mdspan b/stl/inc/mdspan
index 9594bf14ce..5506590b7c 100644
--- a/stl/inc/mdspan
+++ b/stl/inc/mdspan
@@ -267,16 +267,12 @@ public:
     }
 };
 
-#if defined(__clang__) || defined(__EDG__) // TRANSITION, REQUIRES REPORT (ICE)
-template <class... _Integrals>
-    requires (is_convertible_v<_Integrals, size_t> && ...)
-extents(_Integrals... _Exts) -> extents<size_t, ((void) _Exts, dynamic_extent)...>;
-#else // ^^^ no workaround / workaround vvv
+template <class>
+inline constexpr size_t _Repeat_dynamic_extent = dynamic_extent;
+
 template <class... _Integrals>
     requires (is_convertible_v<_Integrals, size_t> && ...)
-extents(_Integrals...)
-    -> extents<size_t, conditional_t<true, integral_constant<size_t, dynamic_extent>, _Integrals>::value...>;
-#endif // ^^^ workaround ^^^
+extents(_Integrals...) -> extents<size_t, _Repeat_dynamic_extent<_Integrals>...>;
 
 template <class _IndexType, class _Indices>
 struct _Dextents_impl;

From d8dd87ebaa4feb7d070918ee9e55037933a8e517 Mon Sep 17 00:00:00 2001
From: Jakub Mazurkiewicz <mazkuba3@gmail.com>
Date: Fri, 7 Apr 2023 00:08:21 +0200
Subject: [PATCH 2/2] Drive-by: alias repeating `layout_right::mapping`

Comment: https://github.com/microsoft/STL/pull/3615#discussion_r1156571002
---
 tests/std/tests/P0009R18_mdspan_layout_right/test.cpp | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/tests/std/tests/P0009R18_mdspan_layout_right/test.cpp b/tests/std/tests/P0009R18_mdspan_layout_right/test.cpp
index 620183f2ac..4810d8a362 100644
--- a/tests/std/tests/P0009R18_mdspan_layout_right/test.cpp
+++ b/tests/std/tests/P0009R18_mdspan_layout_right/test.cpp
@@ -183,12 +183,10 @@ constexpr void check_construction_from_other_left_mapping() {
     }
 
     { // Check implicit conversions
-        static_assert(!NotImplicitlyConstructibleFrom<layout_right::mapping<extents<int, 3>>,
-                      layout_left::mapping<extents<int, 3>>>);
-        static_assert(NotImplicitlyConstructibleFrom<layout_right::mapping<extents<int, 3>>,
-            layout_left::mapping<extents<long long, 3>>>);
-        static_assert(NotImplicitlyConstructibleFrom<layout_right::mapping<extents<int, 3>>,
-            layout_left::mapping<extents<int, dynamic_extent>>>);
+        using Mapping = layout_right::mapping<extents<int, 4>>;
+        static_assert(!NotImplicitlyConstructibleFrom<Mapping, layout_left::mapping<extents<int, 4>>>);
+        static_assert(NotImplicitlyConstructibleFrom<Mapping, layout_left::mapping<extents<long long, 4>>>);
+        static_assert(NotImplicitlyConstructibleFrom<Mapping, layout_left::mapping<extents<int, dynamic_extent>>>);
     }
 }