From 4d5242bfabfae7582a8fe1327d7e43f2d7c98e24 Mon Sep 17 00:00:00 2001
From: Paul Grosse-Bley <paul.grosse-bley@ziti.uni-heidelberg.de>
Date: Tue, 21 May 2024 14:43:46 +0200
Subject: [PATCH] Fix missing restriction on ElementType

It needs to be the same as AccessorPolicy::element_type.
---
 include/experimental/__p0009_bits/mdspan.hpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/experimental/__p0009_bits/mdspan.hpp b/include/experimental/__p0009_bits/mdspan.hpp
index d6ec49e6..af484824 100644
--- a/include/experimental/__p0009_bits/mdspan.hpp
+++ b/include/experimental/__p0009_bits/mdspan.hpp
@@ -34,6 +34,8 @@ class mdspan
 private:
   static_assert(detail::__is_extents_v<Extents>,
                 MDSPAN_IMPL_STANDARD_NAMESPACE_STRING "::mdspan's Extents template parameter must be a specialization of " MDSPAN_IMPL_STANDARD_NAMESPACE_STRING "::extents.");
+  static_assert(std::is_same<ElementType, typename AccessorPolicy::element_type>::value,
+                MDSPAN_IMPL_STANDARD_NAMESPACE_STRING "::mdspan's ElementType template parameter must be the same as its AccessorPolicy::element_type.");
 
   // Workaround for non-deducibility of the index sequence template parameter if it's given at the top level
   template <class>