diff --git a/include/experimental/__p0009_bits/extents.hpp b/include/experimental/__p0009_bits/extents.hpp
index e1b522c4..d19b5928 100644
--- a/include/experimental/__p0009_bits/extents.hpp
+++ b/include/experimental/__p0009_bits/extents.hpp
@@ -55,6 +55,14 @@ __check_compatible_extents(
   return {};
 }
 
+template<class IndexType, class ... Arguments>
+MDSPAN_INLINE_FUNCTION
+static constexpr bool are_valid_indices() {
+    return 
+      (std::is_convertible_v<Arguments, IndexType> && ... && true) &&
+      (std::is_nothrow_constructible_v<IndexType, Arguments> && ... && true);
+}
+
 // ------------------------------------------------------------------
 // ------------ static_array ----------------------------------------
 // ------------------------------------------------------------------
@@ -499,17 +507,20 @@ template <class IndexType, size_t... Extents> class extents {
 public:
 
   // Converting constructor from other extents specializations
-  MDSPAN_TEMPLATE_REQUIRES(
-      class OtherIndexType, size_t... OtherExtents,
-      /* requires */
-      (
-          /* multi-stage check to protect from invalid pack expansion when sizes
-             don't match? */
-          decltype(detail::__check_compatible_extents(
-              std::integral_constant<bool, sizeof...(Extents) ==
-                                               sizeof...(OtherExtents)>{},
+    MDSPAN_TEMPLATE_REQUIRES(
+        class OtherIndexType, size_t... OtherExtents,
+        /* requires */
+        (
+            /* multi-stage check to protect from invalid pack expansion when sizes
+            don't match? */
+            decltype(detail::__check_compatible_extents(
+              // using: sizeof...(Extents) == sizeof...(OtherExtents) as the second argument fails with MSVC+NVCC with some obscure expansion error
+              // MSVC: 19.38.33133 NVCC: 12.0
+              std::integral_constant<bool, extents<int, Extents...>::rank() == extents<int, OtherExtents...>::rank()>{},
               std::integer_sequence<size_t, Extents...>{},
-              std::integer_sequence<size_t, OtherExtents...>{}))::value))
+              std::integer_sequence<size_t, OtherExtents...>{}))::value
+      )
+  )
   MDSPAN_INLINE_FUNCTION
   MDSPAN_CONDITIONAL_EXPLICIT((((Extents != dynamic_extent) &&
                                 (OtherExtents == dynamic_extent)) ||
diff --git a/include/experimental/__p0009_bits/layout_left.hpp b/include/experimental/__p0009_bits/layout_left.hpp
index a7219db6..7468692e 100644
--- a/include/experimental/__p0009_bits/layout_left.hpp
+++ b/include/experimental/__p0009_bits/layout_left.hpp
@@ -189,10 +189,7 @@ class layout_left::mapping {
       class... Indices,
       /* requires */ (
         (sizeof...(Indices) == extents_type::rank()) &&
-        _MDSPAN_FOLD_AND(
-           (_MDSPAN_TRAIT(std::is_convertible, Indices, index_type) &&
-            _MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, Indices))
-        )
+        (detail::are_valid_indices<index_type, Indices...>())
       )
     )
     _MDSPAN_HOST_DEVICE
diff --git a/include/experimental/__p0009_bits/layout_right.hpp b/include/experimental/__p0009_bits/layout_right.hpp
index caab43ff..46313497 100644
--- a/include/experimental/__p0009_bits/layout_right.hpp
+++ b/include/experimental/__p0009_bits/layout_right.hpp
@@ -188,13 +188,10 @@ class layout_right::mapping {
     //--------------------------------------------------------------------------------
 
     MDSPAN_TEMPLATE_REQUIRES(
-      class... Indices,
+      class ... Indices,
       /* requires */ (
-        (sizeof...(Indices) == extents_type::rank()) &&
-        _MDSPAN_FOLD_AND(
-           (_MDSPAN_TRAIT(std::is_convertible, Indices, index_type) &&
-            _MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, Indices))
-        )
+      (sizeof...(Indices) == extents_type::rank()) &&
+      (detail::are_valid_indices<index_type, Indices...>())
       )
     )
     _MDSPAN_HOST_DEVICE
diff --git a/include/experimental/__p0009_bits/layout_stride.hpp b/include/experimental/__p0009_bits/layout_stride.hpp
index b42d2703..9318495e 100644
--- a/include/experimental/__p0009_bits/layout_stride.hpp
+++ b/include/experimental/__p0009_bits/layout_stride.hpp
@@ -424,8 +424,7 @@ struct layout_stride {
       class... Indices,
       /* requires */ (
         sizeof...(Indices) == Extents::rank() &&
-        _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_convertible, Indices, index_type) /*&& ...*/ ) &&
-        _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, Indices) /*&& ...*/)
+        (detail::are_valid_indices<index_type, Indices...>())
       )
     )
     MDSPAN_FORCE_INLINE_FUNCTION
diff --git a/include/experimental/__p0009_bits/mdspan.hpp b/include/experimental/__p0009_bits/mdspan.hpp
index e976ab87..d6ec49e6 100644
--- a/include/experimental/__p0009_bits/mdspan.hpp
+++ b/include/experimental/__p0009_bits/mdspan.hpp
@@ -116,9 +116,8 @@ class mdspan
   MDSPAN_TEMPLATE_REQUIRES(
     class... SizeTypes,
     /* requires */ (
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_convertible, SizeTypes, index_type) /* && ... */) &&
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, SizeTypes) /* && ... */) &&
       ((sizeof...(SizeTypes) == rank()) || (sizeof...(SizeTypes) == rank_dynamic())) &&
+      (detail::are_valid_indices<index_type, SizeTypes...>()) &&
       _MDSPAN_TRAIT(std::is_constructible, mapping_type, extents_type) &&
       _MDSPAN_TRAIT(std::is_default_constructible, accessor_type)
     )
@@ -282,9 +281,8 @@ class mdspan
   MDSPAN_TEMPLATE_REQUIRES(
     class... SizeTypes,
     /* requires */ (
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_convertible, SizeTypes, index_type) /* && ... */) &&
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT(std::is_nothrow_constructible, index_type, SizeTypes) /* && ... */) &&
-      extents_type::rank() == sizeof...(SizeTypes)
+      extents_type::rank() == sizeof...(SizeTypes) &&
+      (detail::are_valid_indices<index_type, SizeTypes...>())
     )
   )
   MDSPAN_FORCE_INLINE_FUNCTION
diff --git a/include/experimental/__p1684_bits/mdarray.hpp b/include/experimental/__p1684_bits/mdarray.hpp
index 2fdf4ccb..bdc5925f 100644
--- a/include/experimental/__p1684_bits/mdarray.hpp
+++ b/include/experimental/__p1684_bits/mdarray.hpp
@@ -103,8 +103,8 @@ class mdarray {
   MDSPAN_TEMPLATE_REQUIRES(
     class... SizeTypes,
     /* requires */ (
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT( std::is_convertible, SizeTypes, index_type) /* && ... */) &&
-      _MDSPAN_TRAIT( std::is_constructible, extents_type, SizeTypes...) &&
+      (::MDSPAN_IMPL_STANDARD_NAMESPACE::detail::are_valid_indices<index_type, SizeTypes...>()) &&
+        _MDSPAN_TRAIT( std::is_constructible, extents_type, SizeTypes...) &&
       _MDSPAN_TRAIT( std::is_constructible, mapping_type, extents_type) &&
       (_MDSPAN_TRAIT( std::is_constructible, container_type, size_t) ||
        container_is_array<container_type>::value) &&
@@ -312,8 +312,8 @@ class mdarray {
   MDSPAN_TEMPLATE_REQUIRES(
     class... SizeTypes,
     /* requires */ (
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT( std::is_convertible, SizeTypes, index_type) /* && ... */) &&
-      extents_type::rank() == sizeof...(SizeTypes)
+        (::MDSPAN_IMPL_STANDARD_NAMESPACE::detail::are_valid_indices<index_type, SizeTypes...>()) &&
+        extents_type::rank() == sizeof...(SizeTypes)
     )
   )
   MDSPAN_FORCE_INLINE_FUNCTION
@@ -324,8 +324,8 @@ class mdarray {
   MDSPAN_TEMPLATE_REQUIRES(
     class... SizeTypes,
     /* requires */ (
-      _MDSPAN_FOLD_AND(_MDSPAN_TRAIT( std::is_convertible, SizeTypes, index_type) /* && ... */) &&
-      extents_type::rank() == sizeof...(SizeTypes)
+        (::MDSPAN_IMPL_STANDARD_NAMESPACE::detail::are_valid_indices<index_type, SizeTypes...>()) &&
+        extents_type::rank() == sizeof...(SizeTypes)
     )
   )
   MDSPAN_FORCE_INLINE_FUNCTION
diff --git a/include/experimental/__p2642_bits/layout_padded.hpp b/include/experimental/__p2642_bits/layout_padded.hpp
index 4b74626b..8af1d00f 100644
--- a/include/experimental/__p2642_bits/layout_padded.hpp
+++ b/include/experimental/__p2642_bits/layout_padded.hpp
@@ -374,11 +374,10 @@ class layout_left_padded<PaddingValue>::mapping {
    * - (is_nothrow_constructible_v<index_type, Indices> && ...) is true.
    */
   MDSPAN_TEMPLATE_REQUIRES(
-    class... _Indices,
-    /* requires */ (
-      sizeof...(_Indices) == extents_type::rank()
-      && (std::is_convertible_v<_Indices, index_type> && ...)
-      && (std::is_nothrow_constructible_v<index_type, _Indices> && ...)
+      class... _Indices,
+      /* requires */ (
+          sizeof...(_Indices) == extents_type::rank() &&
+          (::MDSPAN_IMPL_STANDARD_NAMESPACE::detail::are_valid_indices<index_type, _Indices...>())
     )
   )
   constexpr size_t operator()(_Indices... idxs) const noexcept
@@ -707,9 +706,8 @@ class layout_right_padded<PaddingValue>::mapping {
   MDSPAN_TEMPLATE_REQUIRES(
       class... _Indices,
       /* requires */ (
-          sizeof...(_Indices) == extents_type::rank()
-          && (std::is_convertible_v<_Indices, index_type> && ...)
-          && (std::is_nothrow_constructible_v<index_type, _Indices> && ...)
+          sizeof...(_Indices) == extents_type::rank() &&
+          (::MDSPAN_IMPL_STANDARD_NAMESPACE::detail::are_valid_indices<index_type, _Indices...>())
           )
       )
   constexpr size_t operator()(_Indices... idxs) const noexcept