From bbeb0bdc91f404aa7758668ac788f91696fb2cd8 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Sat, 28 Sep 2019 12:54:18 -0700
Subject: [PATCH 1/8] initial deprecation of multi_span and strided_span

---
 include/gsl/multi_span       | 229 +++++++++++++++--------------------
 tests/bounds_tests.cpp       |   2 +-
 tests/multi_span_tests.cpp   |   2 +-
 tests/strided_span_tests.cpp |   2 +-
 4 files changed, 103 insertions(+), 132 deletions(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index 0c1506e..d705978 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -49,13 +49,14 @@
 #pragma warning(disable : 26473) // in some instantiations we cast to the same type
 #pragma warning(disable : 26490) // TODO: bug in parser - attributes and templates
 #pragma warning(disable : 26465) // TODO: bug - suppression does not work on template functions
+#pragma warning(disable : 4996)  // use of function or classes marked [[deprecated]]
 
 #if _MSC_VER < 1910
 #pragma push_macro("constexpr")
 #define constexpr /*constexpr*/
 
-#endif                          // _MSC_VER < 1910
-#endif                          // _MSC_VER
+#endif // _MSC_VER < 1910
+#endif // _MSC_VER
 
 // GCC 7 does not like the signed unsigned missmatch (size_t ptrdiff_t)
 // While there is a conversion from signed to unsigned, it happens at
@@ -95,8 +96,7 @@ namespace details
 } // namespace details
 
 template <std::size_t Rank>
-class multi_span_index final
-{
+class [[deprecated]] multi_span_index final {
     static_assert(Rank > 0, "Rank must be greater than 0!");
 
     template <std::size_t OtherRank>
@@ -111,7 +111,7 @@ public:
 
     constexpr multi_span_index() noexcept {}
 
-    constexpr multi_span_index(const value_type (&values)[Rank]) noexcept
+    constexpr multi_span_index(const value_type(&values)[Rank]) noexcept
     {
         GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
         GSL_SUPPRESS(bounds.3) // NO-FORMAT: attribute
@@ -139,7 +139,7 @@ public:
     // Preconditions: component_idx < rank
     GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute
     GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-    constexpr const_reference operator[](std::size_t component_idx) const 
+    constexpr const_reference operator[](std::size_t component_idx) const
     {
         Expects(component_idx < Rank); // Component index must be less than rank
         return elems[component_idx];
@@ -152,10 +152,7 @@ public:
         return std::equal(elems, elems + rank, rhs.elems);
     }
 
-    constexpr bool operator!=(const multi_span_index& rhs) const
-    {
-        return !(*this == rhs);
-    }
+    constexpr bool operator!=(const multi_span_index& rhs) const { return !(*this == rhs); }
 
     constexpr multi_span_index operator+() const noexcept { return *this; }
 
@@ -184,8 +181,7 @@ public:
     {
         GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
         GSL_SUPPRESS(bounds.3) // NO-FORMAT: attribute
-        std::transform(elems, elems + rank, rhs.elems, elems,
-                       std::plus<value_type>{});
+        std::transform(elems, elems + rank, rhs.elems, elems, std::plus<value_type>{});
         return *this;
     }
 
@@ -240,7 +236,7 @@ private:
 
 #if !defined(_MSC_VER) || _MSC_VER >= 1910
 
-struct static_bounds_dynamic_range_t
+struct [[deprecated]] static_bounds_dynamic_range_t
 {
     template <typename T, typename = std::enable_if_t<std::is_integral<T>::value>>
     constexpr operator T() const noexcept
@@ -288,12 +284,10 @@ constexpr static_bounds_dynamic_range_t dynamic_range{};
 const std::ptrdiff_t dynamic_range = -1;
 #endif
 
-struct generalized_mapping_tag
-{
-};
-struct contiguous_mapping_tag : generalized_mapping_tag
+struct [[deprecated]] generalized_mapping_tag
 {
 };
+struct[[deprecated]] contiguous_mapping_tag : generalized_mapping_tag{};
 
 namespace details
 {
@@ -305,8 +299,7 @@ namespace details
     };
 
     template <std::ptrdiff_t... Ranges>
-    struct BoundsRanges
-    {
+    struct [[deprecated]] BoundsRanges {
         using size_type = std::ptrdiff_t;
         static const size_type Depth = 0;
         static const size_type DynamicNum = 0;
@@ -345,7 +338,7 @@ namespace details
     };
 
     template <std::ptrdiff_t... RestRanges>
-    struct BoundsRanges<dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>
+    struct[[deprecated]] BoundsRanges<dynamic_range, RestRanges...> : BoundsRanges<RestRanges...>
     {
         using Base = BoundsRanges<RestRanges...>;
         using size_type = std::ptrdiff_t;
@@ -358,8 +351,9 @@ namespace details
         size_type m_bound;
 
     public:
-        GSL_SUPPRESS(f.23) // NO-FORMAT: attribute // this pointer type is cannot be assigned nullptr - issue in not_null
-        GSL_SUPPRESS(bounds.1)  // NO-FORMAT: attribute
+        GSL_SUPPRESS(
+            f.23) // NO-FORMAT: attribute // this pointer type is cannot be assigned nullptr - issue in not_null
+        GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
         constexpr BoundsRanges(const std::ptrdiff_t* const arr)
             : Base(arr + 1), m_bound(*arr * this->Base::totalSize())
         {
@@ -370,13 +364,13 @@ namespace details
 
         template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
         constexpr BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other,
-                     bool /* firstLevel */ = true)
+                               bool /* firstLevel */ = true)
             : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
             , m_bound(other.totalSize())
         {}
 
         template <typename T, std::size_t Dim = 0>
-        constexpr void serialize(T& arr) const
+        constexpr void serialize(T & arr) const
         {
             arr[Dim] = elementNum();
             this->Base::template serialize<T, Dim + 1>(arr);
@@ -400,19 +394,19 @@ namespace details
             return cur < m_bound ? cur + last : -1;
         }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
-        constexpr size_type totalSize() const noexcept
-        {
-            return m_bound;
-        }
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        constexpr size_type totalSize() const noexcept { return m_bound; }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
         constexpr size_type elementNum() const noexcept
         {
             return totalSize() / this->Base::totalSize();
         }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
         constexpr size_type elementNum(std::size_t dim) const noexcept
         {
             if (dim > 0)
@@ -429,7 +423,7 @@ namespace details
     };
 
     template <std::ptrdiff_t CurRange, std::ptrdiff_t... RestRanges>
-    struct BoundsRanges<CurRange, RestRanges...> : BoundsRanges<RestRanges...>
+    struct[[deprecated]] BoundsRanges<CurRange, RestRanges...> : BoundsRanges<RestRanges...>
     {
         using Base = BoundsRanges<RestRanges...>;
         using size_type = std::ptrdiff_t;
@@ -444,7 +438,7 @@ namespace details
 
         template <std::ptrdiff_t OtherRange, std::ptrdiff_t... RestOtherRanges>
         constexpr BoundsRanges(const BoundsRanges<OtherRange, RestOtherRanges...>& other,
-                     bool firstLevel = true)
+                               bool firstLevel = true)
             : Base(static_cast<const BoundsRanges<RestOtherRanges...>&>(other), false)
         {
             GSL_SUPPRESS(type.4) // NO-FORMAT: attribute // TODO: false positive
@@ -452,7 +446,7 @@ namespace details
         }
 
         template <typename T, std::size_t Dim = 0>
-        constexpr void serialize(T& arr) const
+        constexpr void serialize(T & arr) const
         {
             arr[Dim] = elementNum();
             this->Base::template serialize<T, Dim + 1>(arr);
@@ -461,12 +455,11 @@ namespace details
         template <typename T, std::size_t Dim = 0>
         constexpr size_type linearize(const T& arr) const
         {
-            GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+            GSL_SUPPRESS(bounds.4)                            // NO-FORMAT: attribute
             Expects(arr[Dim] >= 0 && arr[Dim] < CurrentRange); // Index is out of range
-            GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
+            GSL_SUPPRESS(bounds.4)                            // NO-FORMAT: attribute
             const ptrdiff_t d = arr[Dim];
-            return this->Base::totalSize() * d +
-                   this->Base::template linearize<T, Dim + 1>(arr);
+            return this->Base::totalSize() * d + this->Base::template linearize<T, Dim + 1>(arr);
         }
 
         template <typename T, std::size_t Dim = 0>
@@ -478,19 +471,19 @@ namespace details
             return this->Base::totalSize() * arr[Dim] + last;
         }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
         constexpr size_type totalSize() const noexcept
         {
             return CurrentRange * this->Base::totalSize();
         }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
-        constexpr size_type elementNum() const noexcept
-        {
-            return CurrentRange;
-        }
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        constexpr size_type elementNum() const noexcept { return CurrentRange; }
 
-        GSL_SUPPRESS(c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
+        GSL_SUPPRESS(
+            c.128) // NO-FORMAT: attribute // no pointers to BoundsRanges should be ever used
         constexpr size_type elementNum(std::size_t dim) const noexcept
         {
             if (dim > 0)
@@ -506,17 +499,14 @@ namespace details
     };
 
     template <typename SourceType, typename TargetType>
-    struct BoundsRangeConvertible
+    struct[[deprecated]] BoundsRangeConvertible
         : public std::integral_constant<bool, (SourceType::TotalSize >= TargetType::TotalSize ||
                                                TargetType::TotalSize == dynamic_range ||
                                                SourceType::TotalSize == dynamic_range ||
-                                               TargetType::TotalSize == 0)>
-    {
-    };
+                                               TargetType::TotalSize == 0)>{};
 
     template <typename TypeChain>
-    struct TypeListIndexer
-    {
+    struct [[deprecated]] TypeListIndexer {
         const TypeChain& obj_;
         constexpr TypeListIndexer(const TypeChain& obj) : obj_(obj) {}
 
@@ -529,13 +519,13 @@ namespace details
         template <std::size_t N, typename MyChain = TypeChain,
                   typename MyBase = typename MyChain::Base>
         constexpr auto getObj(std::false_type)
-            -> decltype(TypeListIndexer<MyBase>(static_cast<const MyBase&>(obj_)).template get<N>())
+            ->decltype(TypeListIndexer<MyBase>(static_cast<const MyBase&>(obj_)).template get<N>())
         {
             return TypeListIndexer<MyBase>(static_cast<const MyBase&>(obj_)).template get<N>();
         }
 
         template <std::size_t N>
-        constexpr auto get() -> decltype(getObj<N - 1>(std::integral_constant<bool, N == 0>()))
+        constexpr auto get()->decltype(getObj<N - 1>(std::integral_constant<bool, N == 0>()))
         {
             return getObj<N - 1>(std::integral_constant<bool, N == 0>());
         }
@@ -555,7 +545,7 @@ namespace details
         for (std::size_t i = 0; i < Rank - 1; ++i)
         {
             GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-                ret[i] = other[i + 1];
+            ret[i] = other[i + 1];
         }
         return ret;
     }
@@ -565,14 +555,13 @@ template <typename IndexType>
 class bounds_iterator;
 
 template <std::ptrdiff_t... Ranges>
-class static_bounds
-{
+class [[deprecated]] static_bounds {
 public:
     static_bounds(const details::BoundsRanges<Ranges...>&) {}
 };
 
 template <std::ptrdiff_t FirstRange, std::ptrdiff_t... RestRanges>
-class static_bounds<FirstRange, RestRanges...>
+class[[deprecated]] static_bounds<FirstRange, RestRanges...>
 {
     using MyRanges = details::BoundsRanges<FirstRange, RestRanges...>;
 
@@ -604,10 +593,10 @@ public:
     template <std::size_t Rank, typename SourceType, typename TargetType,
               typename Ret = BoundsRangeConvertible2<typename SourceType::Base,
                                                      typename TargetType::Base, Rank>>
-    static auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type) -> Ret;
+    static auto helpBoundsRangeConvertible(SourceType, TargetType, std::true_type)->Ret;
 
     template <std::size_t Rank, typename SourceType, typename TargetType>
-    static auto helpBoundsRangeConvertible(SourceType, TargetType, ...) -> std::false_type;
+    static auto helpBoundsRangeConvertible(SourceType, TargetType, ...)->std::false_type;
 
     template <typename SourceType, typename TargetType, std::size_t Rank>
     struct BoundsRangeConvertible2
@@ -724,10 +713,7 @@ public:
         return !(*this == rhs);
     }
 
-    constexpr const_iterator begin() const noexcept
-    {
-        return const_iterator(*this, index_type{});
-    }
+    constexpr const_iterator begin() const noexcept { return const_iterator(*this, index_type{}); }
 
     constexpr const_iterator end() const noexcept
     {
@@ -736,7 +722,7 @@ public:
 };
 
 template <std::size_t Rank>
-class strided_bounds {
+class [[deprecated]] strided_bounds {
     template <std::size_t OtherRank>
     friend class strided_bounds;
 
@@ -760,14 +746,13 @@ public:
 
     constexpr strided_bounds& operator=(const strided_bounds&) noexcept = default;
 
-    constexpr strided_bounds(const value_type (&values)[rank], index_type strides)
+    constexpr strided_bounds(const value_type(&values)[rank], index_type strides)
         : m_extents(values), m_strides(std::move(strides))
     {}
 
     constexpr strided_bounds(const index_type& extents, const index_type& strides) noexcept
         : m_extents(extents), m_strides(strides)
-    {
-    }
+    {}
 
     constexpr index_type strides() const noexcept { return m_strides; }
 
@@ -839,21 +824,14 @@ private:
 };
 
 template <typename T>
-struct is_bounds : std::integral_constant<bool, false>
-{
-};
+struct[[deprecated]] is_bounds : std::integral_constant<bool, false>{};
 template <std::ptrdiff_t... Ranges>
-struct is_bounds<static_bounds<Ranges...>> : std::integral_constant<bool, true>
-{
-};
+struct[[deprecated]] is_bounds<static_bounds<Ranges...>> : std::integral_constant<bool, true>{};
 template <std::size_t Rank>
-struct is_bounds<strided_bounds<Rank>> : std::integral_constant<bool, true>
-{
-};
+struct[[deprecated]] is_bounds<strided_bounds<Rank>> : std::integral_constant<bool, true>{};
 
 template <typename IndexType>
-class bounds_iterator
-{
+class [[deprecated]] bounds_iterator {
 public:
     static const std::size_t rank = IndexType::rank;
     using iterator_category = std::random_access_iterator_tag;
@@ -974,7 +952,6 @@ public:
         return curr_ == rhs.curr_;
     }
 
-
     constexpr bool operator!=(const bounds_iterator& rhs) const noexcept { return !(*this == rhs); }
 
     constexpr bool operator<(const bounds_iterator& rhs) const noexcept
@@ -988,16 +965,15 @@ public:
 
     constexpr bool operator>=(const bounds_iterator& rhs) const noexcept { return !(rhs > *this); }
 
-    void swap(bounds_iterator& rhs) noexcept
+    void swap(bounds_iterator & rhs) noexcept
     {
         std::swap(boundary_, rhs.boundary_);
         std::swap(curr_, rhs.curr_);
     }
 
 private:
-
     GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-    constexpr bool less(index_type& one, index_type& other) const noexcept
+    constexpr bool less(index_type & one, index_type & other) const noexcept
     {
         for (std::size_t i = 0; i < rank; ++i)
         {
@@ -1228,8 +1204,7 @@ namespace details
 } // namespace details
 
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-class multi_span
-{
+class [[deprecated("This concept is not present in the C++ Core Guidelines")]] multi_span {
     // TODO do we still need this?
     template <typename ValueType2, std::ptrdiff_t FirstDimension2,
               std::ptrdiff_t... RestDimensions2>
@@ -1262,8 +1237,7 @@ private:
 public:
     // default constructor - same as constructing from nullptr_t
     GSL_SUPPRESS(type.6) // NO-FORMAT: attribute // TODO: false positive
-    constexpr multi_span() noexcept
-        : multi_span(nullptr, bounds_type{})
+    constexpr multi_span() noexcept : multi_span(nullptr, bounds_type{})
     {
         static_assert(bounds_type::dynamic_rank != 0 ||
                           (bounds_type::dynamic_rank == 0 && bounds_type::static_size == 0),
@@ -1273,8 +1247,7 @@ public:
 
     // construct from nullptr - get an empty multi_span
     GSL_SUPPRESS(type.6) // NO-FORMAT: attribute // TODO: false positive
-    constexpr multi_span(std::nullptr_t) noexcept
-        : multi_span(nullptr, bounds_type{})
+    constexpr multi_span(std::nullptr_t) noexcept : multi_span(nullptr, bounds_type{})
     {
         static_assert(bounds_type::dynamic_rank != 0 ||
                           (bounds_type::dynamic_rank == 0 && bounds_type::static_size == 0),
@@ -1298,8 +1271,7 @@ public:
     // construct from a single element
 
     GSL_SUPPRESS(type.6) // NO-FORMAT: attribute // TODO: false positive
-    constexpr multi_span(reference data) noexcept
-        : multi_span(&data, bounds_type{1})
+    constexpr multi_span(reference data) noexcept : multi_span(&data, bounds_type{1})
     {
         static_assert(bounds_type::dynamic_rank > 0 || bounds_type::static_size == 0 ||
                           bounds_type::static_size == 1,
@@ -1308,17 +1280,14 @@ public:
     }
 
     // prevent constructing from temporaries for single-elements
-    constexpr multi_span(value_type&&) = delete;
+    constexpr multi_span(value_type &&) = delete;
 
     // construct from pointer + length
     GSL_SUPPRESS(type.6) // NO-FORMAT: attribute // TODO: false positive
-    constexpr multi_span(pointer ptr, size_type size)
-        : multi_span(ptr, bounds_type{size})
-    {}
+    constexpr multi_span(pointer ptr, size_type size) : multi_span(ptr, bounds_type{size}) {}
 
     // construct from pointer + length - multidimensional
-    constexpr multi_span(pointer data, bounds_type bounds)
-        : data_(data), bounds_(std::move(bounds))
+    constexpr multi_span(pointer data, bounds_type bounds) : data_(data), bounds_(std::move(bounds))
     {
         Expects((bounds_.size() > 0 && data != nullptr) || bounds_.size() == 0);
     }
@@ -1336,7 +1305,7 @@ public:
 
     // construct from n-dimensions static array
     template <typename T, std::size_t N, typename Helper = details::SpanArrayTraits<T, N>>
-    constexpr multi_span(T (&arr)[N])
+    constexpr multi_span(T(&arr)[N])
         : multi_span(reinterpret_cast<pointer>(arr), bounds_type{typename Helper::bounds_type{}})
     {
         static_assert(std::is_convertible<typename Helper::value_type(*)[], value_type(*)[]>::value,
@@ -1357,7 +1326,7 @@ public:
 
     // construct from std::array
     template <typename T, std::size_t N>
-    constexpr multi_span(std::array<T, N>& arr)
+    constexpr multi_span(std::array<T, N> & arr)
         : multi_span(arr.data(), bounds_type{static_bounds<N>{}})
     {
         static_assert(
@@ -1381,7 +1350,7 @@ public:
 
     // prevent constructing from temporary std::array
     template <typename T, std::size_t N>
-    constexpr multi_span(std::array<T, N>&& arr) = delete;
+    constexpr multi_span(std::array<T, N> && arr) = delete;
 
     // construct from containers
     // future: could use contiguous_iterator_traits to identify only contiguous containers
@@ -1389,11 +1358,11 @@ public:
     template <typename Cont, typename DataType = typename Cont::value_type,
               typename = std::enable_if_t<
                   !details::is_multi_span<Cont>::value &&
-                  std::is_convertible<DataType (*)[], value_type (*)[]>::value &&
+                  std::is_convertible<DataType(*)[], value_type(*)[]>::value &&
                   std::is_same<std::decay_t<decltype(std::declval<Cont>().size(),
                                                      *std::declval<Cont>().data())>,
                                DataType>::value>>
-    constexpr multi_span(Cont& cont)
+    constexpr multi_span(Cont & cont)
         : multi_span(static_cast<pointer>(cont.data()),
                      details::newBoundsHelper<bounds_type>(narrow_cast<size_type>(cont.size())))
     {}
@@ -1402,11 +1371,11 @@ public:
     template <typename Cont, typename DataType = typename Cont::value_type,
               typename = std::enable_if_t<
                   !details::is_multi_span<Cont>::value &&
-                  std::is_convertible<DataType (*)[], value_type (*)[]>::value &&
+                  std::is_convertible<DataType(*)[], value_type(*)[]>::value &&
                   std::is_same<std::decay_t<decltype(std::declval<Cont>().size(),
                                                      *std::declval<Cont>().data())>,
                                DataType>::value>>
-    explicit constexpr multi_span(Cont&& cont) = delete;
+    explicit constexpr multi_span(Cont && cont) = delete;
 
     // construct from a convertible multi_span
     template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
@@ -1419,7 +1388,7 @@ public:
 
     // trivial copy and move
     constexpr multi_span(const multi_span&) = default;
-    constexpr multi_span(multi_span&&) = default;
+    constexpr multi_span(multi_span &&) = default;
 
     // trivial assignment
     constexpr multi_span& operator=(const multi_span&) = default;
@@ -1493,8 +1462,7 @@ public:
     }
 
     // section - creates a non-contiguous, strided multi_span from a contiguous one
-    constexpr strided_span<ValueType, Rank> section(index_type origin,
-                                                    index_type extents) const
+    constexpr strided_span<ValueType, Rank> section(index_type origin, index_type extents) const
     {
         const size_type size = this->bounds().total_size() - this->bounds().linearize(origin);
         return {&this->operator[](origin), size,
@@ -1636,8 +1604,8 @@ public:
     template <typename OtherValueType, std::ptrdiff_t... OtherDimensions,
               typename = std::enable_if_t<std::is_same<std::remove_cv_t<value_type>,
                                                        std::remove_cv_t<OtherValueType>>::value>>
-    constexpr bool operator>(const multi_span<OtherValueType, OtherDimensions...>& other) const
-        noexcept
+    constexpr bool operator>(const multi_span<OtherValueType, OtherDimensions...>& other)
+        const noexcept
     {
         return (other < *this);
     }
@@ -1659,7 +1627,7 @@ public:
 // DimCount and Enabled here are workarounds for a bug in MSVC 2015
 template <typename SpanType, typename... Dimensions2, std::size_t DimCount = sizeof...(Dimensions2),
           bool Enabled = (DimCount > 0), typename = std::enable_if_t<Enabled>>
-constexpr auto as_multi_span(SpanType s, Dimensions2... dims)
+[[deprecated]] constexpr auto as_multi_span(SpanType s, Dimensions2... dims)
     -> multi_span<typename SpanType::value_type, Dimensions2::value...>
 {
     static_assert(details::is_multi_span<SpanType>::value,
@@ -1673,7 +1641,8 @@ constexpr auto as_multi_span(SpanType s, Dimensions2... dims)
 
 // convert a multi_span<T> to a multi_span<const byte>
 template <typename U, std::ptrdiff_t... Dimensions>
-multi_span<const byte, dynamic_range> as_bytes(multi_span<U, Dimensions...> s) noexcept
+[[deprecated]] multi_span<const byte, dynamic_range>
+as_bytes(multi_span<U, Dimensions...> s) noexcept
 {
     static_assert(std::is_trivial<std::decay_t<U>>::value,
                   "The value_type of multi_span must be a trivial type.");
@@ -1685,7 +1654,7 @@ multi_span<const byte, dynamic_range> as_bytes(multi_span<U, Dimensions...> s) n
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-multi_span<byte> as_writeable_bytes(multi_span<U, Dimensions...> s) noexcept
+[[deprecated]] multi_span<byte> as_writeable_bytes(multi_span<U, Dimensions...> s) noexcept
 {
     static_assert(std::is_trivial<std::decay_t<U>>::value,
                   "The value_type of multi_span must be a trivial type.");
@@ -1697,7 +1666,7 @@ multi_span<byte> as_writeable_bytes(multi_span<U, Dimensions...> s) noexcept
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-constexpr auto as_multi_span(multi_span<const byte, Dimensions...> s) -> multi_span<
+[[deprecated]] constexpr auto as_multi_span(multi_span<const byte, Dimensions...> s) -> multi_span<
     const U, static_cast<std::ptrdiff_t>(
                  multi_span<const byte, Dimensions...>::bounds_type::static_size != dynamic_range
                      ? (static_cast<std::size_t>(
@@ -1723,7 +1692,7 @@ constexpr auto as_multi_span(multi_span<const byte, Dimensions...> s) -> multi_s
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-constexpr auto as_multi_span(multi_span<byte, Dimensions...> s)
+[[deprecated]] constexpr auto as_multi_span(multi_span<byte, Dimensions...> s)
     -> multi_span<U, narrow_cast<std::ptrdiff_t>(
                          multi_span<byte, Dimensions...>::bounds_type::static_size != dynamic_range
                              ? static_cast<std::size_t>(
@@ -1743,7 +1712,7 @@ constexpr auto as_multi_span(multi_span<byte, Dimensions...> s)
 }
 
 template <typename T, std::ptrdiff_t... Dimensions>
-constexpr auto as_multi_span(T* const& ptr, dim_t<Dimensions>... args)
+[[deprecated]] constexpr auto as_multi_span(T* const& ptr, dim_t<Dimensions>... args)
     -> multi_span<std::remove_all_extents_t<T>, Dimensions...>
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr),
@@ -1752,41 +1721,42 @@ constexpr auto as_multi_span(T* const& ptr, dim_t<Dimensions>... args)
 }
 
 template <typename T>
-constexpr auto as_multi_span(T* arr, std::ptrdiff_t len) ->
+[[deprecated]] constexpr auto as_multi_span(T* arr, std::ptrdiff_t len) ->
     typename details::SpanArrayTraits<T, dynamic_range>::type
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, std::size_t N>
-constexpr auto as_multi_span(T (&arr)[N]) -> typename details::SpanArrayTraits<T, N>::type
+[[deprecated]] constexpr auto as_multi_span(T (&arr)[N]) ->
+    typename details::SpanArrayTraits<T, N>::type
 {
     return {arr};
 }
 
 template <typename T, std::size_t N>
-constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>& arr)
+[[deprecated]] constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T, std::size_t N>
-constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>&&) = delete;
+[[deprecated]] constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>&&) = delete;
 
 template <typename T, std::size_t N>
-constexpr multi_span<T, N> as_multi_span(std::array<T, N>& arr)
+[[deprecated]] constexpr multi_span<T, N> as_multi_span(std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T>
-constexpr multi_span<T, dynamic_range> as_multi_span(T* begin, T* end)
+[[deprecated]] constexpr multi_span<T, dynamic_range> as_multi_span(T* begin, T* end)
 {
     return {begin, end};
 }
 
 template <typename Cont>
-constexpr auto as_multi_span(Cont& arr) -> std::enable_if_t<
+[[deprecated]] constexpr auto as_multi_span(Cont& arr) -> std::enable_if_t<
     !details::is_multi_span<std::decay_t<Cont>>::value,
     multi_span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
@@ -1795,14 +1765,14 @@ constexpr auto as_multi_span(Cont& arr) -> std::enable_if_t<
 }
 
 template <typename Cont>
-constexpr auto as_multi_span(Cont&& arr) -> std::enable_if_t<
+[[deprecated]] constexpr auto as_multi_span(Cont&& arr) -> std::enable_if_t<
     !details::is_multi_span<std::decay_t<Cont>>::value,
     multi_span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 // from basic_string which doesn't have nonconst .data() member like other contiguous containers
 template <typename CharT, typename Traits, typename Allocator>
 GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-constexpr auto as_multi_span(std::basic_string<CharT, Traits, Allocator>& str)
+[[deprecated]] constexpr auto as_multi_span(std::basic_string<CharT, Traits, Allocator>& str)
     -> multi_span<CharT, dynamic_range>
 {
     Expects(str.size() < PTRDIFF_MAX);
@@ -2055,8 +2025,7 @@ private:
 };
 
 template <class Span>
-class contiguous_span_iterator
-{
+class [[deprecated]] contiguous_span_iterator {
 public:
     using iterator_category = std::random_access_iterator_tag;
     using value_type = typename Span::value_type;
@@ -2072,7 +2041,8 @@ private:
     const Span* m_validator;
 
     GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute
-    void validateThis() const {
+    void validateThis() const
+    {
         // iterator is out of range of the array
         Expects(data_ >= m_validator->data_ && data_ < m_validator->data_ + m_validator->size());
     }
@@ -2161,7 +2131,7 @@ public:
     bool operator>(const contiguous_span_iterator& rhs) const { return rhs < *this; }
     bool operator>=(const contiguous_span_iterator& rhs) const { return !(rhs > *this); }
 
-    void swap(contiguous_span_iterator& rhs) noexcept
+    void swap(contiguous_span_iterator & rhs) noexcept
     {
         std::swap(data_, rhs.data_);
         std::swap(m_validator, rhs.m_validator);
@@ -2176,7 +2146,8 @@ contiguous_span_iterator<Span> operator+(typename contiguous_span_iterator<Span>
 }
 
 template <typename Span>
-class general_span_iterator {
+class [[deprecated(
+          "This concept is not present in the C++ Core Guidelines")]] general_span_iterator {
 public:
     using iterator_category = std::random_access_iterator_tag;
     using value_type = typename Span::value_type;
@@ -2259,7 +2230,7 @@ public:
     bool operator<=(const general_span_iterator& rhs) const { return !(rhs < *this); }
     bool operator>(const general_span_iterator& rhs) const { return rhs < *this; }
     bool operator>=(const general_span_iterator& rhs) const { return !(rhs > *this); }
-    void swap(general_span_iterator& rhs) noexcept
+    void swap(general_span_iterator & rhs) noexcept
     {
         std::swap(m_itr, rhs.m_itr);
         std::swap(m_container, rhs.m_container);
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index e586d44..1de4e1a 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -17,7 +17,7 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
+#pragma warning(disable : 26440 26426 4996) // from catch deprecated
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, TEST_CASE
diff --git a/tests/multi_span_tests.cpp b/tests/multi_span_tests.cpp
index 7e3ec89..3aaf2f9 100644
--- a/tests/multi_span_tests.cpp
+++ b/tests/multi_span_tests.cpp
@@ -17,7 +17,7 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
+#pragma warning(disable : 26440 26426 4996) // from catch deprecated
 
 #endif
 
diff --git a/tests/strided_span_tests.cpp b/tests/strided_span_tests.cpp
index 1563d90..949b1c2 100644
--- a/tests/strided_span_tests.cpp
+++ b/tests/strided_span_tests.cpp
@@ -17,7 +17,7 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426) // from catch
+#pragma warning(disable : 26440 26426 4996) // from catch deprecated
 
 #endif
 

From e026971c03ea0495f9623d9aad7a9beca24b5692 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Wed, 2 Oct 2019 15:40:15 -0700
Subject: [PATCH 2/8] deprecation, removing cassert

---
 include/gsl/multi_span | 1 -
 1 file changed, 1 deletion(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index d705978..e67b811 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -23,7 +23,6 @@
 
 #include <algorithm> // for transform, lexicographical_compare
 #include <array>     // for array
-#include <cassert>
 #include <cstddef>          // for ptrdiff_t, size_t, nullptr_t
 #include <cstdint>          // for PTRDIFF_MAX
 #include <functional>       // for divides, multiplies, minus, negate, plus

From eb995b36714c6c8639da25ea90f8f4f73017e8ca Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Wed, 2 Oct 2019 16:17:46 -0700
Subject: [PATCH 3/8] deprecating strided_span

---
 include/gsl/multi_span       | 2 +-
 tests/bounds_tests.cpp       | 4 +++-
 tests/multi_span_tests.cpp   | 4 +++-
 tests/strided_span_tests.cpp | 4 +++-
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index e67b811..eac4397 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -1781,7 +1781,7 @@ GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
 // strided_span is an extension that is not strictly part of the GSL at this time.
 // It is kept here while the multidimensional interface is still being defined.
 template <typename ValueType, std::size_t Rank>
-class strided_span
+class [[deprecated]] strided_span
 {
 public:
     using bounds_type = strided_bounds<Rank>;
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index 1de4e1a..29c198a 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -17,7 +17,9 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426 4996) // from catch deprecated
+#pragma warning(disable : 26440 26426) // from catch
+#pragma warning(disable : 4996)  // use of function or classes marked [[deprecated]]
+
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, TEST_CASE
diff --git a/tests/multi_span_tests.cpp b/tests/multi_span_tests.cpp
index 3aaf2f9..97b2271 100644
--- a/tests/multi_span_tests.cpp
+++ b/tests/multi_span_tests.cpp
@@ -17,7 +17,9 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426 4996) // from catch deprecated
+#pragma warning(disable : 26440 26426) // from catch 
+#pragma warning(disable : 4996) // multi_span is in the process of being deprecated. 
+                                // Suppressing warnings until it is completely removed
 
 #endif
 
diff --git a/tests/strided_span_tests.cpp b/tests/strided_span_tests.cpp
index 949b1c2..0d0896a 100644
--- a/tests/strided_span_tests.cpp
+++ b/tests/strided_span_tests.cpp
@@ -17,7 +17,9 @@
 #ifdef _MSC_VER
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
-#pragma warning(disable : 26440 26426 4996) // from catch deprecated
+#pragma warning(disable : 26440 26426) // from catch deprecated
+#pragma warning(disable : 4996) // strided_span is in the process of being deprecated. 
+                                // Suppressing warnings until it is completely removed
 
 #endif
 

From 5e4463a7c19cca78b949d094f1e364bece769485 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Thu, 3 Oct 2019 15:47:25 -0700
Subject: [PATCH 4/8] removing function deprecation, adding additional class /
 struct deprecations

---
 include/gsl/multi_span | 77 +++++++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 38 deletions(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index eac4397..4ea5c83 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -76,18 +76,18 @@ namespace gsl
 namespace details
 {
     template <typename SizeType>
-    struct SizeTypeTraits
+    struct [[deprecated]] SizeTypeTraits
     {
         static const SizeType max_value = std::numeric_limits<SizeType>::max();
     };
 
     template <typename... Ts>
-    class are_integral : public std::integral_constant<bool, true>
+    class [[deprecated]] are_integral : public std::integral_constant<bool, true>
     {
     };
 
     template <typename T, typename... Ts>
-    class are_integral<T, Ts...>
+    class [[deprecated]] are_integral<T, Ts...>
         : public std::integral_constant<bool,
                                         std::is_integral<T>::value && are_integral<Ts...>::value>
     {
@@ -292,7 +292,7 @@ namespace details
 {
 
     template <std::ptrdiff_t Left, std::ptrdiff_t Right>
-    struct LessThan
+    struct [[deprecated]] LessThan
     {
         static const bool value = Left < Right;
     };
@@ -551,7 +551,7 @@ namespace details
 } // namespace details
 
 template <typename IndexType>
-class bounds_iterator;
+class [[deprecated]] bounds_iterator;
 
 template <std::ptrdiff_t... Ranges>
 class [[deprecated]] static_bounds {
@@ -1067,17 +1067,17 @@ namespace details
 } // namespace details
 
 template <typename Span>
-class contiguous_span_iterator;
+class [[deprecated]] contiguous_span_iterator;
 template <typename Span>
-class general_span_iterator;
+class [[deprecated]] general_span_iterator;
 
 template <std::ptrdiff_t DimSize = dynamic_range>
-struct dim_t
+struct [[deprecated]] dim_t
 {
     static const std::ptrdiff_t value = DimSize;
 };
 template <>
-struct dim_t<dynamic_range>
+struct [[deprecated]] dim_t<dynamic_range>
 {
     static const std::ptrdiff_t value = dynamic_range;
     const std::ptrdiff_t dvalue;
@@ -1098,28 +1098,30 @@ constexpr dim_t<N> dim(std::ptrdiff_t n) noexcept
 
 template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range,
           std::ptrdiff_t... RestDimensions>
-class multi_span;
+class [[deprecated]] multi_span;
+
 template <typename ValueType, std::size_t Rank>
-class strided_span;
+class [[deprecated]] strided_span;
 
 namespace details
 {
     template <typename T, typename = std::true_type>
-    struct SpanTypeTraits
+    struct [[deprecated]] SpanTypeTraits
     {
         using value_type = T;
         using size_type = std::size_t;
     };
 
     template <typename Traits>
-    struct SpanTypeTraits<Traits, typename std::is_reference<typename Traits::span_traits&>::type>
+    struct [[deprecated]] SpanTypeTraits<
+        Traits, typename std::is_reference<typename Traits::span_traits&>::type>
     {
         using value_type = typename Traits::span_traits::value_type;
         using size_type = typename Traits::span_traits::size_type;
     };
 
     template <typename T, std::ptrdiff_t... Ranks>
-    struct SpanArrayTraits
+    struct [[deprecated]] SpanArrayTraits
     {
         using type = multi_span<T, Ranks...>;
         using value_type = T;
@@ -1128,7 +1130,7 @@ namespace details
         using reference = T&;
     };
     template <typename T, std::ptrdiff_t N, std::ptrdiff_t... Ranks>
-    struct SpanArrayTraits<T[N], Ranks...> : SpanArrayTraits<T, Ranks..., N>
+    struct [[deprecated]] SpanArrayTraits<T[N], Ranks...> : SpanArrayTraits<T, Ranks..., N>
     {
     };
 
@@ -1152,7 +1154,7 @@ namespace details
             totalSize, std::integral_constant<bool, BoundsType::dynamic_rank == 1>());
     }
 
-    struct Sep
+    struct [[deprecated]] Sep
     {
     };
 
@@ -1175,29 +1177,29 @@ namespace details
     }
 
     template <typename... Dimensions>
-    struct static_as_multi_span_static_bounds_helper
+    struct [[deprecated]] static_as_multi_span_static_bounds_helper
     {
         using type = static_bounds<(Dimensions::value)...>;
     };
 
     template <typename T>
-    struct is_multi_span_oracle : std::false_type
+    struct [[deprecated]] is_multi_span_oracle : std::false_type
     {
     };
 
     template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-    struct is_multi_span_oracle<multi_span<ValueType, FirstDimension, RestDimensions...>>
+    struct [[deprecated]] is_multi_span_oracle<multi_span<ValueType, FirstDimension, RestDimensions...>>
         : std::true_type
     {
     };
 
     template <typename ValueType, std::ptrdiff_t Rank>
-    struct is_multi_span_oracle<strided_span<ValueType, Rank>> : std::true_type
+    struct [[deprecated]] is_multi_span_oracle<strided_span<ValueType, Rank>> : std::true_type
     {
     };
 
     template <typename T>
-    struct is_multi_span : is_multi_span_oracle<std::remove_cv_t<T>>
+    struct [[deprecated]] is_multi_span : is_multi_span_oracle<std::remove_cv_t<T>>
     {
     };
 } // namespace details
@@ -1626,7 +1628,7 @@ public:
 // DimCount and Enabled here are workarounds for a bug in MSVC 2015
 template <typename SpanType, typename... Dimensions2, std::size_t DimCount = sizeof...(Dimensions2),
           bool Enabled = (DimCount > 0), typename = std::enable_if_t<Enabled>>
-[[deprecated]] constexpr auto as_multi_span(SpanType s, Dimensions2... dims)
+constexpr auto as_multi_span(SpanType s, Dimensions2... dims)
     -> multi_span<typename SpanType::value_type, Dimensions2::value...>
 {
     static_assert(details::is_multi_span<SpanType>::value,
@@ -1640,7 +1642,7 @@ template <typename SpanType, typename... Dimensions2, std::size_t DimCount = siz
 
 // convert a multi_span<T> to a multi_span<const byte>
 template <typename U, std::ptrdiff_t... Dimensions>
-[[deprecated]] multi_span<const byte, dynamic_range>
+multi_span<const byte, dynamic_range>
 as_bytes(multi_span<U, Dimensions...> s) noexcept
 {
     static_assert(std::is_trivial<std::decay_t<U>>::value,
@@ -1653,7 +1655,7 @@ as_bytes(multi_span<U, Dimensions...> s) noexcept
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-[[deprecated]] multi_span<byte> as_writeable_bytes(multi_span<U, Dimensions...> s) noexcept
+multi_span<byte> as_writeable_bytes(multi_span<U, Dimensions...> s) noexcept
 {
     static_assert(std::is_trivial<std::decay_t<U>>::value,
                   "The value_type of multi_span must be a trivial type.");
@@ -1665,7 +1667,7 @@ template <typename U, std::ptrdiff_t... Dimensions>
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-[[deprecated]] constexpr auto as_multi_span(multi_span<const byte, Dimensions...> s) -> multi_span<
+constexpr auto as_multi_span(multi_span<const byte, Dimensions...> s) -> multi_span<
     const U, static_cast<std::ptrdiff_t>(
                  multi_span<const byte, Dimensions...>::bounds_type::static_size != dynamic_range
                      ? (static_cast<std::size_t>(
@@ -1691,7 +1693,7 @@ template <typename U, std::ptrdiff_t... Dimensions>
 // on all implementations. It should be considered an experimental extension
 // to the standard GSL interface.
 template <typename U, std::ptrdiff_t... Dimensions>
-[[deprecated]] constexpr auto as_multi_span(multi_span<byte, Dimensions...> s)
+constexpr auto as_multi_span(multi_span<byte, Dimensions...> s)
     -> multi_span<U, narrow_cast<std::ptrdiff_t>(
                          multi_span<byte, Dimensions...>::bounds_type::static_size != dynamic_range
                              ? static_cast<std::size_t>(
@@ -1711,7 +1713,7 @@ template <typename U, std::ptrdiff_t... Dimensions>
 }
 
 template <typename T, std::ptrdiff_t... Dimensions>
-[[deprecated]] constexpr auto as_multi_span(T* const& ptr, dim_t<Dimensions>... args)
+constexpr auto as_multi_span(T* const& ptr, dim_t<Dimensions>... args)
     -> multi_span<std::remove_all_extents_t<T>, Dimensions...>
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(ptr),
@@ -1720,42 +1722,42 @@ template <typename T, std::ptrdiff_t... Dimensions>
 }
 
 template <typename T>
-[[deprecated]] constexpr auto as_multi_span(T* arr, std::ptrdiff_t len) ->
+constexpr auto as_multi_span(T* arr, std::ptrdiff_t len) ->
     typename details::SpanArrayTraits<T, dynamic_range>::type
 {
     return {reinterpret_cast<std::remove_all_extents_t<T>*>(arr), len};
 }
 
 template <typename T, std::size_t N>
-[[deprecated]] constexpr auto as_multi_span(T (&arr)[N]) ->
+constexpr auto as_multi_span(T (&arr)[N]) ->
     typename details::SpanArrayTraits<T, N>::type
 {
     return {arr};
 }
 
 template <typename T, std::size_t N>
-[[deprecated]] constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>& arr)
+constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T, std::size_t N>
-[[deprecated]] constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>&&) = delete;
+constexpr multi_span<const T, N> as_multi_span(const std::array<T, N>&&) = delete;
 
 template <typename T, std::size_t N>
-[[deprecated]] constexpr multi_span<T, N> as_multi_span(std::array<T, N>& arr)
+constexpr multi_span<T, N> as_multi_span(std::array<T, N>& arr)
 {
     return {arr};
 }
 
 template <typename T>
-[[deprecated]] constexpr multi_span<T, dynamic_range> as_multi_span(T* begin, T* end)
+constexpr multi_span<T, dynamic_range> as_multi_span(T* begin, T* end)
 {
     return {begin, end};
 }
 
 template <typename Cont>
-[[deprecated]] constexpr auto as_multi_span(Cont& arr) -> std::enable_if_t<
+constexpr auto as_multi_span(Cont& arr) -> std::enable_if_t<
     !details::is_multi_span<std::decay_t<Cont>>::value,
     multi_span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>>
 {
@@ -1764,14 +1766,14 @@ template <typename Cont>
 }
 
 template <typename Cont>
-[[deprecated]] constexpr auto as_multi_span(Cont&& arr) -> std::enable_if_t<
+constexpr auto as_multi_span(Cont&& arr) -> std::enable_if_t<
     !details::is_multi_span<std::decay_t<Cont>>::value,
     multi_span<std::remove_reference_t<decltype(arr.size(), *arr.data())>, dynamic_range>> = delete;
 
 // from basic_string which doesn't have nonconst .data() member like other contiguous containers
 template <typename CharT, typename Traits, typename Allocator>
 GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute
-[[deprecated]] constexpr auto as_multi_span(std::basic_string<CharT, Traits, Allocator>& str)
+constexpr auto as_multi_span(std::basic_string<CharT, Traits, Allocator>& str)
     -> multi_span<CharT, dynamic_range>
 {
     Expects(str.size() < PTRDIFF_MAX);
@@ -2145,8 +2147,7 @@ contiguous_span_iterator<Span> operator+(typename contiguous_span_iterator<Span>
 }
 
 template <typename Span>
-class [[deprecated(
-          "This concept is not present in the C++ Core Guidelines")]] general_span_iterator {
+class [[deprecated]] general_span_iterator {
 public:
     using iterator_category = std::random_access_iterator_tag;
     using value_type = typename Span::value_type;

From 7adf7eb6fe4c8d90a60df6ba2833b55146f79716 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Thu, 3 Oct 2019 17:52:49 -0700
Subject: [PATCH 5/8] new messages

---
 include/gsl/multi_span | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index 4ea5c83..d2b2a69 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -1098,10 +1098,10 @@ constexpr dim_t<N> dim(std::ptrdiff_t n) noexcept
 
 template <typename ValueType, std::ptrdiff_t FirstDimension = dynamic_range,
           std::ptrdiff_t... RestDimensions>
-class [[deprecated]] multi_span;
+class [[deprecated("gsl::multi_span is deprecated because it is not in the C++ Core Guidelines")]] multi_span;
 
 template <typename ValueType, std::size_t Rank>
-class [[deprecated]] strided_span;
+class [[deprecated("gsl::strided_span is deprecated because it is not in the C++ Core Guidelines")]] strided_span;
 
 namespace details
 {
@@ -1205,7 +1205,7 @@ namespace details
 } // namespace details
 
 template <typename ValueType, std::ptrdiff_t FirstDimension, std::ptrdiff_t... RestDimensions>
-class [[deprecated("This concept is not present in the C++ Core Guidelines")]] multi_span {
+class [[deprecated("gsl::multi_span is deprecated because it is not in the C++ Core Guidelines")]] multi_span {
     // TODO do we still need this?
     template <typename ValueType2, std::ptrdiff_t FirstDimension2,
               std::ptrdiff_t... RestDimensions2>
@@ -1783,7 +1783,7 @@ constexpr auto as_multi_span(std::basic_string<CharT, Traits, Allocator>& str)
 // strided_span is an extension that is not strictly part of the GSL at this time.
 // It is kept here while the multidimensional interface is still being defined.
 template <typename ValueType, std::size_t Rank>
-class [[deprecated]] strided_span
+class [[deprecated("gsl::strided_span is deprecated because it is not in the C++ Core Guidelines")]] strided_span
 {
 public:
     using bounds_type = strided_bounds<Rank>;

From 2b8f7aea325ed2ef193d572599820aad098ebf40 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Fri, 4 Oct 2019 12:38:55 -0700
Subject: [PATCH 6/8] adding clang/gcc suppression of the deprecation warnings.

---
 include/gsl/multi_span       |  9 +++++++++
 tests/bounds_tests.cpp       |  8 ++++++++
 tests/multi_span_tests.cpp   | 10 +++++++++-
 tests/strided_span_tests.cpp |  8 ++++++++
 4 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/include/gsl/multi_span b/include/gsl/multi_span
index d2b2a69..3a2d982 100644
--- a/include/gsl/multi_span
+++ b/include/gsl/multi_span
@@ -57,6 +57,11 @@
 #endif // _MSC_VER < 1910
 #endif // _MSC_VER
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#endif
+
 // GCC 7 does not like the signed unsigned missmatch (size_t ptrdiff_t)
 // While there is a conversion from signed to unsigned, it happens at
 // compiletime, so the compiler wouldn't have to warn indiscriminently, but
@@ -2261,4 +2266,8 @@ general_span_iterator<Span> operator+(typename general_span_iterator<Span>::diff
 #pragma GCC diagnostic pop
 #endif // __GNUC__ > 6
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
 #endif // GSL_MULTI_SPAN_H
diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index 29c198a..da29e91 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -19,7 +19,11 @@
 // so people aren't annoyed by them when running the tool.
 #pragma warning(disable : 26440 26426) // from catch
 #pragma warning(disable : 4996)  // use of function or classes marked [[deprecated]]
+#endif
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, TEST_CASE
@@ -115,3 +119,7 @@ TEST_CASE("bounds_convertible")
 #ifdef CONFIRM_COMPILATION_ERRORS
 copy(src_span_static, dst_span_static);
 #endif
+
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic pop
+#endif
\ No newline at end of file
diff --git a/tests/multi_span_tests.cpp b/tests/multi_span_tests.cpp
index 97b2271..c4532bb 100644
--- a/tests/multi_span_tests.cpp
+++ b/tests/multi_span_tests.cpp
@@ -18,9 +18,13 @@
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
 #pragma warning(disable : 26440 26426) // from catch 
-#pragma warning(disable : 4996) // multi_span is in the process of being deprecated. 
+//#pragma warning(disable : 4996) // multi_span is in the process of being deprecated. 
                                 // Suppressing warnings until it is completely removed
+#endif
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, CHECK...
@@ -1785,3 +1789,7 @@ TEST_CASE("iterator")
 #ifdef CONFIRM_COMPILATION_ERRORS
 copy(src_span_static, dst_span_static);
 #endif
+
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic pop
+#endif
diff --git a/tests/strided_span_tests.cpp b/tests/strided_span_tests.cpp
index 0d0896a..f201df4 100644
--- a/tests/strided_span_tests.cpp
+++ b/tests/strided_span_tests.cpp
@@ -20,7 +20,11 @@
 #pragma warning(disable : 26440 26426) // from catch deprecated
 #pragma warning(disable : 4996) // strided_span is in the process of being deprecated. 
                                 // Suppressing warnings until it is completely removed
+#endif
 
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
 
 #include <catch/catch.hpp> // for AssertionHandler, StringRef, CHECK, CHECK...
@@ -796,3 +800,7 @@ TEST_CASE("strided_span_conversion")
         i++;
     }
 }
+
+#if __clang__ || __GNUC__
+#pragma GCC diagnostic pop
+#endif

From 6ff4a5287df1108851bb5cdc0803da746e69f1ce Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Fri, 4 Oct 2019 14:13:54 -0700
Subject: [PATCH 7/8] accidentally commented out pragma

---
 tests/multi_span_tests.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/multi_span_tests.cpp b/tests/multi_span_tests.cpp
index c4532bb..7c3e87c 100644
--- a/tests/multi_span_tests.cpp
+++ b/tests/multi_span_tests.cpp
@@ -18,7 +18,7 @@
 // blanket turn off warnings from CppCoreCheck from catch
 // so people aren't annoyed by them when running the tool.
 #pragma warning(disable : 26440 26426) // from catch 
-//#pragma warning(disable : 4996) // multi_span is in the process of being deprecated. 
+#pragma warning(disable : 4996) // multi_span is in the process of being deprecated. 
                                 // Suppressing warnings until it is completely removed
 #endif
 

From 4b289d4cf08724984f91b33832f277ab1a018d1f Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Fri, 4 Oct 2019 14:15:24 -0700
Subject: [PATCH 8/8] lack of nl for bounds_test

---
 tests/bounds_tests.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/bounds_tests.cpp b/tests/bounds_tests.cpp
index da29e91..d72e31a 100644
--- a/tests/bounds_tests.cpp
+++ b/tests/bounds_tests.cpp
@@ -122,4 +122,4 @@ copy(src_span_static, dst_span_static);
 
 #if __clang__ || __GNUC__
 #pragma GCC diagnostic pop
-#endif
\ No newline at end of file
+#endif