diff --git a/include/gsl/string_span b/include/gsl/string_span
index 658cf84..6daf546 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -17,31 +17,9 @@
 #ifndef GSL_STRING_SPAN_H
 #define GSL_STRING_SPAN_H
 
-#include "assert"   // for Ensures, Expects
-#include "span_ext" // for operator!=, operator==, dynamic_extent
-#include "util"     // for narrow_cast
+#include "span_ext" // for dynamic_extent
 
-#include <algorithm> // for equal, lexicographical_compare
-#include <array>     // for array
 #include <cstddef>   // for size_t, nullptr_t
-#include <cstdint>   // for PTRDIFF_MAX
-#include <cstring>
-#include <string>      // for basic_string, allocator, char_traits
-#include <type_traits> // for declval, is_convertible, enable_if_t, add_...
-
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(push)
-
-// Turn MSVC /analyze rules that generate too much noise. TODO: fix in the tool.
-#pragma warning(disable : 26446) // TODO: bug in parser - attributes and templates
-#pragma warning(disable : 26481) // TODO: suppress does not work inside templates sometimes
-#pragma warning(disable : 4996)  // use of functions & classes marked [[deprecated]]
-#endif                           // _MSC_VER
-
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#endif
 
 namespace gsl
 {
@@ -75,685 +53,6 @@ using u16zstring = basic_zstring<char16_t, dynamic_extent>;
 
 using u32zstring = basic_zstring<char32_t, dynamic_extent>;
 
-namespace details
-{
-    template <class CharT>
-    [[deprecated("string_span was removed from the C++ Core Guidelines. For more information, see "
-                 "isocpp/CppCoreGuidelines PR#1680")]] constexpr std::size_t
-    string_length(const CharT* str, std::size_t n)
-    {
-        if (str == nullptr || n == dynamic_extent) return 0;
-
-        const span<const CharT> str_span{str, n};
-
-        std::size_t len = 0;
-        while (len < n && str_span[len]) len++;
-
-        return len;
-    }
-} // namespace details
-
-//
-// ensure_sentinel()
-//
-// Provides a way to obtain an span from a contiguous sequence
-// that ends with a (non-inclusive) sentinel value.
-//
-// Will fail-fast if sentinel cannot be found before max elements are examined.
-//
-template <typename T, const T Sentinel>
-[[deprecated("string_span was removed from the C++ Core Guidelines. For more information, see "
-             "isocpp/CppCoreGuidelines PR#1680")]] constexpr span<T, dynamic_extent>
-ensure_sentinel(T* seq, std::size_t max = static_cast<std::size_t>(-1))
-{
-    Ensures(seq != nullptr);
-
-    // clang-format off
-    GSL_SUPPRESS(f.23) // TODO: false positive // TODO: suppress does not work
-    // clang-format on
-    auto cur = seq;
-    Ensures(cur != nullptr); // workaround for removing the warning
-
-    // clang-format off
-    GSL_SUPPRESS(bounds.1) // TODO: suppress does not work
-    // clang-format on
-    while (static_cast<std::size_t>(cur - seq) < max && *cur != Sentinel) ++cur;
-    Ensures(*cur == Sentinel);
-    return {seq, static_cast<std::size_t>(cur - seq)};
-}
-
-//
-// ensure_z - creates a span for a zero terminated strings. The span will not contain the zero
-// termination. Will fail fast if a null-terminator cannot be found before the limit of size_type.
-//
-template <typename CharT>
-[[deprecated("string_span was removed from the C++ Core Guidelines. For more information, see "
-             "isocpp/CppCoreGuidelines PR#1680")]] constexpr span<CharT, dynamic_extent>
-ensure_z(CharT* const& sz, std::size_t max = static_cast<std::size_t>(-1))
-{
-    return ensure_sentinel<CharT, CharT(0)>(sz, max);
-}
-
-template <typename CharT, std::size_t N>
-constexpr span<CharT, dynamic_extent> ensure_z(CharT (&sz)[N])
-{
-    return ensure_z(&sz[0], N);
-}
-
-template <class Cont>
-[[deprecated(
-    "string_span was removed from the C++ Core Guidelines. For more information, see "
-    "isocpp/CppCoreGuidelines PR#1680")]] constexpr span<typename std::
-                                                             remove_pointer<
-                                                                 typename Cont::pointer>::type,
-                                                         dynamic_extent>
-ensure_z(Cont& cont)
-{
-    return ensure_z(cont.data(), cont.size());
-}
-
-template <typename CharT, std::size_t>
-class [[deprecated("string_span was removed from the C++ Core Guidelines. For more information, "
-                   "see isocpp/CppCoreGuidelines PR#1680")]] basic_string_span;
-
-namespace details
-{
-    template <typename T>
-    struct [[deprecated(
-        "string_span was removed from the C++ Core Guidelines. For more information, "
-        "see isocpp/CppCoreGuidelines PR#1680")]] is_basic_string_span_oracle : std::false_type{};
-
-    template <typename CharT, std::size_t Extent>
-    struct [[deprecated(
-        "string_span was removed from the C++ Core Guidelines. For more information, see "
-        "isocpp/CppCoreGuidelines PR#1680")]] is_basic_string_span_oracle<basic_string_span<CharT,
-                                                                                            Extent>>
-        : std::true_type{};
-
-    template <typename T>
-    struct [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                        "information, see isocpp/CppCoreGuidelines PR#1680")]] is_basic_string_span
-        : is_basic_string_span_oracle<std::remove_cv_t<T>>{};
-} // namespace details
-
-//
-// string_span and relatives
-//
-template <typename CharT, std::size_t Extent = dynamic_extent>
-class [[deprecated("string_span was removed from the C++ Core Guidelines. For more information, "
-                   "see isocpp/CppCoreGuidelines PR#1680")]] basic_string_span
-{
-public:
-    using element_type = CharT;
-    using value_type = std::remove_cv_t<element_type>;
-    using pointer = std::add_pointer_t<element_type>;
-    using reference = std::add_lvalue_reference_t<element_type>;
-    using const_reference = std::add_lvalue_reference_t<std::add_const_t<element_type>>;
-    using impl_type = span<element_type, Extent>;
-
-    using size_type = typename impl_type::size_type;
-    using iterator = typename impl_type::iterator;
-    using reverse_iterator = typename impl_type::reverse_iterator;
-
-    // default (empty)
-    constexpr basic_string_span() noexcept = default;
-
-    // copy
-    constexpr basic_string_span(const basic_string_span& other) noexcept = default;
-
-    // assign
-    constexpr basic_string_span& operator=(const basic_string_span& other) noexcept = default;
-
-    constexpr basic_string_span(pointer ptr, size_type length) : span_(ptr, length) {}
-    constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}
-
-    // From static arrays - if 0-terminated, remove 0 from the view
-    // All other containers allow 0s within the length, so we do not remove them
-    template <std::size_t N>
-    constexpr basic_string_span(element_type(&arr)[N]) : span_(remove_z(arr))
-    {}
-
-    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
-    constexpr basic_string_span(std::array<ArrayElementType, N> & arr) noexcept : span_(arr)
-    {}
-
-    template <std::size_t N, class ArrayElementType = std::remove_const_t<element_type>>
-    constexpr basic_string_span(const std::array<ArrayElementType, N>& arr) noexcept : span_(arr)
-    {}
-
-    // Container signature should work for basic_string after C++17 version exists
-    template <class Traits, class Allocator>
-    // GSL_SUPPRESS(bounds.4) // TODO: parser bug
-    constexpr basic_string_span(std::basic_string<element_type, Traits, Allocator> & str)
-        : span_(&str[0], str.length())
-    {}
-
-    template <class Traits, class Allocator>
-    constexpr basic_string_span(const std::basic_string<element_type, Traits, Allocator>& str)
-        : span_(&str[0], str.length())
-    {}
-
-    // from containers. Containers must have a pointer type and data() function signatures
-    template <class Container,
-              class = std::enable_if_t<
-                  !details::is_basic_string_span<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr basic_string_span(Container & cont) : span_(cont)
-    {}
-
-    template <class Container,
-              class = std::enable_if_t<
-                  !details::is_basic_string_span<Container>::value &&
-                  std::is_convertible<typename Container::pointer, pointer>::value &&
-                  std::is_convertible<typename Container::pointer,
-                                      decltype(std::declval<Container>().data())>::value>>
-    constexpr basic_string_span(const Container& cont) : span_(cont)
-    {}
-
-    // from string_span
-    template <
-        class OtherValueType, std::size_t OtherExtent,
-        class = std::enable_if_t<std::is_convertible<
-            typename basic_string_span<OtherValueType, OtherExtent>::impl_type, impl_type>::value>>
-    constexpr basic_string_span(basic_string_span<OtherValueType, OtherExtent> other)
-        : span_(other.data(), other.length())
-    {}
-
-    template <size_type Count>
-    constexpr basic_string_span<element_type, Count> first() const
-    {
-        return {span_.template first<Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent> first(size_type count) const
-    {
-        return {span_.first(count)};
-    }
-
-    template <size_type Count>
-    constexpr basic_string_span<element_type, Count> last() const
-    {
-        return {span_.template last<Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent> last(size_type count) const
-    {
-        return {span_.last(count)};
-    }
-
-    template <size_type Offset, size_type Count>
-    constexpr basic_string_span<element_type, Count> subspan() const
-    {
-        return {span_.template subspan<Offset, Count>()};
-    }
-
-    constexpr basic_string_span<element_type, dynamic_extent> subspan(
-        size_type offset, size_type count = dynamic_extent) const
-    {
-        return {span_.subspan(offset, count)};
-    }
-
-    constexpr reference operator[](size_type idx) const { return span_[idx]; }
-    constexpr reference operator()(size_type idx) const { return span_[idx]; }
-
-    constexpr pointer data() const { return span_.data(); }
-
-    constexpr size_type length() const noexcept { return span_.size(); }
-    constexpr size_type size() const noexcept { return span_.size(); }
-    constexpr size_type size_bytes() const noexcept { return span_.size_bytes(); }
-    constexpr size_type length_bytes() const noexcept { return span_.length_bytes(); }
-    constexpr bool empty() const noexcept { return size() == 0; }
-
-    constexpr iterator begin() const noexcept { return span_.begin(); }
-    constexpr iterator end() const noexcept { return span_.end(); }
-
-    constexpr reverse_iterator rbegin() const noexcept { return span_.rbegin(); }
-    constexpr reverse_iterator rend() const noexcept { return span_.rend(); }
-
-private:
-    static constexpr impl_type remove_z(pointer const& sz, std::size_t max)
-    {
-        return impl_type(sz, details::string_length(sz, max));
-    }
-
-    template <std::size_t N>
-    static constexpr impl_type remove_z(element_type(&sz)[N])
-    {
-        return remove_z(&sz[0], N);
-    }
-
-    impl_type span_;
-};
-
-template <std::size_t Extent = dynamic_extent>
-using string_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                               "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<const char, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using wstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cwstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                 "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<const wchar_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u16string_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                  "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu16string_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                   "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<const char16_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using u32string_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                  "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<char32_t, Extent>;
-
-template <std::size_t Extent = dynamic_extent>
-using cu32string_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                   "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_string_span<const char32_t, Extent>;
-
-//
-// to_string() allow (explicit) conversions from string_span to string
-//
-
-template <typename CharT, std::size_t Extent>
-constexpr std::basic_string<typename std::remove_const<CharT>::type>
-to_string(basic_string_span<CharT, Extent> view)
-{
-    return {view.data(), narrow_cast<std::size_t>(view.length())};
-}
-
-template <typename CharT, typename Traits = typename std::char_traits<CharT>,
-          typename Allocator = std::allocator<CharT>, typename gCharT, std::size_t Extent>
-constexpr std::basic_string<CharT, Traits, Allocator>
-to_basic_string(basic_string_span<gCharT, Extent> view)
-{
-    return {view.data(), narrow_cast<std::size_t>(view.length())};
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr basic_string_span<const byte, details::calculate_byte_size<ElementType, Extent>::value>
-as_bytes(basic_string_span<ElementType, Extent> s) noexcept
-{
-    // clang-format off
-    GSL_SUPPRESS(type.1)
-    // clang-format on
-    return {reinterpret_cast<const byte*>(s.data()), s.size_bytes()};
-}
-
-template <class ElementType, std::size_t Extent,
-          class = std::enable_if_t<!std::is_const<ElementType>::value>>
-constexpr basic_string_span<byte, details::calculate_byte_size<ElementType, Extent>::value>
-as_writable_bytes(basic_string_span<ElementType, Extent> s) noexcept
-{
-    // clang-format off
-    GSL_SUPPRESS(type.1)
-    // clang-format on
-    return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
-}
-
-// zero-terminated string span, used to convert
-// zero-terminated spans to legacy strings
-template <typename CharT, std::size_t Extent = dynamic_extent>
-class [[deprecated("string_span was removed from the C++ Core Guidelines. For more information, "
-                   "see isocpp/CppCoreGuidelines PR#1680")]] basic_zstring_span
-{
-public:
-    using value_type = CharT;
-    using const_value_type = std::add_const_t<CharT>;
-
-    using pointer = std::add_pointer_t<value_type>;
-    using const_pointer = std::add_pointer_t<const_value_type>;
-
-    using zstring_type = basic_zstring<value_type, Extent>;
-    using const_zstring_type = basic_zstring<const_value_type, Extent>;
-
-    using impl_type = span<value_type, Extent>;
-    using string_span_type = basic_string_span<value_type, Extent>;
-
-    constexpr basic_zstring_span(impl_type s) : span_(s)
-    {
-        // expects a zero-terminated span
-        Expects(s.size() > 0);
-        Expects(s[s.size() - 1] == value_type{});
-    }
-
-    // copy
-    constexpr basic_zstring_span(const basic_zstring_span& other) = default;
-
-    // move
-    constexpr basic_zstring_span(basic_zstring_span && other) noexcept = default;
-
-    // assign
-    constexpr basic_zstring_span& operator=(const basic_zstring_span& other) = default;
-
-    // move assign
-    constexpr basic_zstring_span& operator=(basic_zstring_span&& other) noexcept = default;
-
-    constexpr bool empty() const noexcept { return false; }
-
-    constexpr string_span_type as_string_span() const noexcept
-    {
-        return {span_.data(), span_.size() - 1};
-    }
-    constexpr string_span_type ensure_z() const { return gsl::ensure_z(span_); }
-
-    constexpr const_zstring_type assume_z() const noexcept { return span_.data(); }
-
-private:
-    impl_type span_;
-};
-
-template <std::size_t Max = dynamic_extent>
-using zstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<char, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using wzstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                 "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<wchar_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using u16zstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                   "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<char16_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using u32zstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                   "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<char32_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using czstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                 "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<const char, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cwzstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For more "
-                                  "information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<const wchar_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cu16zstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For "
-                                    "more information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<const char16_t, Max>;
-
-template <std::size_t Max = dynamic_extent>
-using cu32zstring_span [[deprecated("string_span was removed from the C++ Core Guidelines. For "
-                                    "more information, see isocpp/CppCoreGuidelines PR#1680")]] =
-    basic_zstring_span<const char32_t, Max>;
-
-// operator ==
-template <class CharT, std::size_t Extent, class T,
-          class = std::enable_if_t<
-              details::is_basic_string_span<T>::value ||
-              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
-bool operator==(const gsl::basic_string_span<CharT, Extent>& one, const T& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(other);
-    return std::equal(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <class CharT, std::size_t Extent, class T,
-          class = std::enable_if_t<
-              !details::is_basic_string_span<T>::value &&
-              std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>>>::value>>
-bool operator==(const T& one, const gsl::basic_string_span<CharT, Extent>& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>> tmp(one);
-    return std::equal(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-
-// operator !=
-template <typename CharT, std::size_t Extent = dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator!=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one == other);
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator!=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one == other);
-}
-
-// operator<
-template <typename CharT, std::size_t Extent = dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    const gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
-    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
-    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(other);
-    return std::lexicographical_compare(one.begin(), one.end(), tmp.begin(), tmp.end());
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    gsl::basic_string_span<std::add_const_t<CharT>, Extent> tmp(one);
-    return std::lexicographical_compare(tmp.begin(), tmp.end(), other.begin(), other.end());
-}
-#endif
-
-// operator <=
-template <typename CharT, std::size_t Extent = dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(other < one);
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(other < one);
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(other < one);
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator<=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(other < one);
-}
-#endif
-
-// operator>
-template <typename CharT, std::size_t Extent = dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return other < one;
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return other < one;
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return other < one;
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return other < one;
-}
-#endif
-
-// operator >=
-template <typename CharT, std::size_t Extent = dynamic_extent, typename T,
-          typename = std::enable_if_t<std::is_convertible<
-              T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value>>
-bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one < other);
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename = std::enable_if_t<
-        std::is_convertible<T, gsl::basic_string_span<std::add_const_t<CharT>, Extent>>::value &&
-        !gsl::details::is_basic_string_span<T>::value>>
-bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one < other);
-}
-
-#ifndef _MSC_VER
-
-// VS treats temp and const containers as convertible to basic_string_span,
-// so the cases below are already covered by the previous operators
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>=(gsl::basic_string_span<CharT, Extent> one, const T& other)
-{
-    return !(one < other);
-}
-
-template <
-    typename CharT, std::size_t Extent = dynamic_extent, typename T,
-    typename DataType = typename T::value_type,
-    typename = std::enable_if_t<
-        !gsl::details::is_span<T>::value && !gsl::details::is_basic_string_span<T>::value &&
-        std::is_convertible<DataType*, CharT*>::value &&
-        std::is_same<std::decay_t<decltype(std::declval<T>().size(), *std::declval<T>().data())>,
-                     DataType>::value>>
-bool operator>=(const T& one, gsl::basic_string_span<CharT, Extent> other)
-{
-    return !(one < other);
-}
-#endif
 } // namespace gsl
 
-#if defined(_MSC_VER) && !defined(__clang__)
-#pragma warning(pop)
-
-#endif // _MSC_VER
-
-#if defined(__GNUC__) || defined(__clang__)
-#pragma GCC diagnostic pop
-#endif
 #endif // GSL_STRING_SPAN_H
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 59a8250..657bde8 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -200,7 +200,7 @@ add_executable(gsl_tests
     span_ext_tests.cpp
     span_tests.cpp
     strict_notnull_tests.cpp
-    string_span_tests.cpp
+    
     utils_tests.cpp
 )
 
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
deleted file mode 100644
index 45a67d9..0000000
--- a/tests/string_span_tests.cpp
+++ /dev/null
@@ -1,1225 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-//
-// Copyright (c) 2015 Microsoft Corporation. All rights reserved.
-//
-// This code is licensed under the MIT License (MIT).
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include <gtest/gtest.h>
-
-#include <gsl/assert>      // for Expects, fail_fast (ptr only)
-#include <gsl/pointers>    // for owner
-#include <gsl/span>        // for span, dynamic_extent
-#include <gsl/string_span> // for basic_string_span, operator==, ensure_z
-
-#include <algorithm>   // for move, find
-#include <cstddef>     // for size_t
-#include <map>         // for map
-#include <string>      // for basic_string, string, char_traits, operat...
-#include <type_traits> // for remove_reference<>::type
-#include <vector>      // for vector, allocator
-
-#include "deathTestCommon.h"
-
-using namespace gsl;
-
-// Generic string functions
-
-namespace generic
-{
-
-template <typename CharT>
-auto strlen(const CharT* s)
-{
-    auto p = s;
-    while (*p) ++p;
-    return p - s;
-}
-
-template <typename CharT>
-auto strnlen(const CharT* s, std::size_t n)
-{
-    return std::find(s, s + n, CharT{0}) - s;
-}
-
-} // namespace generic
-
-namespace
-{
-
-template <typename T>
-T move_wrapper(T&& t)
-{
-    return std::move(t);
-}
-
-// not used otherwise
-#ifdef CONFIRM_COMPILATION_ERRORS
-
-template <class T>
-T create()
-{
-    return T{};
-}
-
-template <class T>
-void use(basic_string_span<T, gsl::dynamic_extent>)
-{}
-#endif
-
-czstring_span<> CreateTempName(string_span<> span)
-{
-    Expects(span.size() > 1);
-
-    std::size_t last = 0;
-    if (span.size() > 4)
-    {
-        span[0] = 't';
-        span[1] = 'm';
-        span[2] = 'p';
-        last = 3;
-    }
-    span[last] = '\0';
-
-    auto ret = span.subspan(0, 4);
-    return {ret};
-}
-
-cwzstring_span<> CreateTempNameW(wstring_span<> span)
-{
-    Expects(span.size() > 1);
-
-    std::size_t last = 0;
-    if (span.size() > 4)
-    {
-        span[0] = L't';
-        span[1] = L'm';
-        span[2] = L'p';
-        last = 3;
-    }
-    span[last] = L'\0';
-
-    auto ret = span.subspan(0, 4);
-    return {ret};
-}
-
-cu16zstring_span<> CreateTempNameU16(u16string_span<> span)
-{
-    Expects(span.size() > 1);
-
-    std::size_t last = 0;
-    if (span.size() > 4)
-    {
-        span[0] = u't';
-        span[1] = u'm';
-        span[2] = u'p';
-        last = 3;
-    }
-    span[last] = u'\0';
-
-    auto ret = span.subspan(0, 4);
-    return {ret};
-}
-
-cu32zstring_span<> CreateTempNameU32(u32string_span<> span)
-{
-    Expects(span.size() > 1);
-
-    std::size_t last = 0;
-    if (span.size() > 4)
-    {
-        span[0] = U't';
-        span[1] = U'm';
-        span[2] = U'p';
-        last = 3;
-    }
-    span[last] = U'\0';
-
-    auto ret = span.subspan(0, 4);
-    return {ret};
-}
-} // namespace
-
-TEST(string_span_tests, TestLiteralConstruction)
-{
-    cwstring_span<> v = ensure_z(L"Hello");
-    EXPECT_TRUE(5 == v.length());
-
-#ifdef CONFIRM_COMPILATION_ERRORS
-    wstring_span<> v2 = ensure0(L"Hello");
-#endif
-}
-
-TEST(string_span_tests, TestConstructFromStdString)
-{
-    std::string s = "Hello there world";
-    cstring_span<> v = s;
-    EXPECT_TRUE(v.length() == static_cast<cstring_span<>::size_type>(s.length()));
-}
-
-TEST(string_span_tests, TestConstructFromStdVector)
-{
-    std::vector<char> vec(5, 'h');
-    string_span<> v{vec};
-    EXPECT_TRUE(v.length() == static_cast<string_span<>::size_type>(vec.size()));
-}
-
-TEST(string_span_tests, TestStackArrayConstruction)
-{
-    wchar_t stack_string[] = L"Hello";
-
-    {
-        cwstring_span<> v = ensure_z(stack_string);
-        EXPECT_TRUE(v.length() == 5);
-    }
-
-    {
-        cwstring_span<> v = stack_string;
-        EXPECT_TRUE(v.length() == 5);
-    }
-
-    {
-        wstring_span<> v = ensure_z(stack_string);
-        EXPECT_TRUE(v.length() == 5);
-    }
-
-    {
-        wstring_span<> v = stack_string;
-        EXPECT_TRUE(v.length() == 5);
-    }
-}
-
-TEST(string_span_tests, TestConstructFromConstCharPointer)
-{
-    const char* s = "Hello";
-    cstring_span<> v = ensure_z(s);
-    EXPECT_TRUE(v.length() == 5);
-}
-
-TEST(string_span_tests, TestConversionToConst)
-{
-    char stack_string[] = "Hello";
-    string_span<> v = ensure_z(stack_string);
-    cstring_span<> v2 = v;
-    EXPECT_TRUE(v.length() == v2.length());
-}
-
-TEST(string_span_tests, TestConversionFromConst)
-{
-    char stack_string[] = "Hello";
-    cstring_span<> v = ensure_z(stack_string);
-    (void) v;
-#ifdef CONFIRM_COMPILATION_ERRORS
-    string_span<> v2 = v;
-    string_span<> v3 = "Hello";
-#endif
-}
-
-TEST(string_span_tests, TestToString)
-{
-    auto s = gsl::to_string(cstring_span<>{});
-    EXPECT_TRUE(s.length() == static_cast<size_t>(0));
-
-    char stack_string[] = "Hello";
-    cstring_span<> v = ensure_z(stack_string);
-    auto s2 = gsl::to_string(v);
-    EXPECT_TRUE(static_cast<cstring_span<>::size_type>(s2.length()) == v.length());
-    EXPECT_TRUE(s2.length() == static_cast<size_t>(5));
-}
-
-TEST(string_span_tests, TestToBasicString)
-{
-    auto s = gsl::to_basic_string<char, std::char_traits<char>, ::std::allocator<char>>(
-        cstring_span<>{});
-    EXPECT_TRUE(s.length() == static_cast<size_t>(0));
-
-    char stack_string[] = "Hello";
-    cstring_span<> v = ensure_z(stack_string);
-    auto s2 = gsl::to_basic_string<char, std::char_traits<char>, ::std::allocator<char>>(v);
-    EXPECT_TRUE(static_cast<cstring_span<>::size_type>(s2.length()) == v.length());
-    EXPECT_TRUE(s2.length() == static_cast<size_t>(5));
-}
-
-TEST(string_span_tests, EqualityAndImplicitConstructors)
-{
-    {
-        cstring_span<> span = "Hello";
-        cstring_span<> span1;
-
-        // comparison to empty span
-        EXPECT_TRUE(span1 != span);
-        EXPECT_TRUE(span != span1);
-    }
-
-    {
-        cstring_span<> span = "Hello";
-        cstring_span<> span1 = "Hello1";
-
-        // comparison to different span
-        EXPECT_TRUE(span1 != span);
-        EXPECT_TRUE(span != span1);
-    }
-
-    {
-        cstring_span<> span = "Hello";
-
-        const char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        const char ar1[] = "Hello";
-        const char ar2[10] = "Hello";
-        const char* ptr = "Hello";
-        const std::string str = "Hello";
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        gsl::span<const char> sp = ensure_z("Hello");
-
-        // comparison to  literal
-        EXPECT_TRUE(span == cstring_span<>("Hello"));
-
-        // comparison to static array with no null termination
-        EXPECT_TRUE(span == cstring_span<>(ar));
-
-        // comparison to static array with null at the end
-        EXPECT_TRUE(span == cstring_span<>(ar1));
-
-        // comparison to static array with null in the middle
-        EXPECT_TRUE(span == cstring_span<>(ar2));
-
-        // comparison to null-terminated c string
-        EXPECT_TRUE(span == cstring_span<>(ptr, 5));
-
-        // comparison to string
-        EXPECT_TRUE(span == cstring_span<>(str));
-
-        // comparison to vector of charaters with no null termination
-        EXPECT_TRUE(span == cstring_span<>(vec));
-
-        // comparison to span
-        EXPECT_TRUE(span == cstring_span<>(sp));
-
-        // comparison to string_span
-        EXPECT_TRUE(span == span);
-    }
-
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-
-        string_span<> span = ar;
-
-        char ar1[] = "Hello";
-        char ar2[10] = "Hello";
-        char* ptr = ar;
-        std::string str = "Hello";
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        gsl::span<char> sp = ensure_z(ar1);
-
-        // comparison to static array with no null termination
-        EXPECT_TRUE(span == string_span<>(ar));
-
-        // comparison to static array with null at the end
-        EXPECT_TRUE(span == string_span<>(ar1));
-
-        // comparison to static array with null in the middle
-        EXPECT_TRUE(span == string_span<>(ar2));
-
-        // comparison to null-terminated c string
-        EXPECT_TRUE(span == string_span<>(ptr, 5));
-
-        // comparison to string
-        EXPECT_TRUE(span == string_span<>(str));
-
-        // comparison to vector of charaters with no null termination
-        EXPECT_TRUE(span == string_span<>(vec));
-
-        // comparison to span
-        EXPECT_TRUE(span == string_span<>(sp));
-
-        // comparison to string_span
-        EXPECT_TRUE(span == span);
-    }
-
-    {
-        const char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        const char ar1[] = "Hello";
-        const char ar2[10] = "Hello";
-        const std::string str = "Hello";
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const gsl::span<const char> sp = ensure_z("Hello");
-
-        cstring_span<> span = "Hello";
-
-        // const span, const other type
-
-        EXPECT_TRUE(span == "Hello");
-        EXPECT_TRUE(span == ar);
-        EXPECT_TRUE(span == ar1);
-        EXPECT_TRUE(span == ar2);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const char* ptr = "Hello";
-        EXPECT_TRUE(span == ptr);
-#endif
-        EXPECT_TRUE(span == str);
-        EXPECT_TRUE(span == vec);
-        EXPECT_TRUE(span == sp);
-
-        EXPECT_TRUE("Hello" == span);
-        EXPECT_TRUE(ar == span);
-        EXPECT_TRUE(ar1 == span);
-        EXPECT_TRUE(ar2 == span);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(ptr == span);
-#endif
-        EXPECT_TRUE(str == span);
-        EXPECT_TRUE(vec == span);
-        EXPECT_TRUE(sp == span);
-
-        // const span, non-const other type
-
-        char _ar[] = {'H', 'e', 'l', 'l', 'o'};
-        char _ar1[] = "Hello";
-        char _ar2[10] = "Hello";
-        char* _ptr = _ar;
-        std::string _str = "Hello";
-        std::vector<char> _vec = {'H', 'e', 'l', 'l', 'o'};
-        gsl::span<char> _sp{_ar, 5};
-
-        EXPECT_TRUE(span == _ar);
-        EXPECT_TRUE(span == _ar1);
-        EXPECT_TRUE(span == _ar2);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(span == _ptr);
-#endif
-        EXPECT_TRUE(span == _str);
-        EXPECT_TRUE(span == _vec);
-        EXPECT_TRUE(span == _sp);
-
-        EXPECT_TRUE(_ar == span);
-        EXPECT_TRUE(_ar1 == span);
-        EXPECT_TRUE(_ar2 == span);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(_ptr == span);
-#endif
-        EXPECT_TRUE(_str == span);
-        EXPECT_TRUE(_vec == span);
-        EXPECT_TRUE(_sp == span);
-
-        string_span<> _span{_ptr, 5};
-
-        // non-const span, non-const other type
-
-        EXPECT_TRUE(_span == _ar);
-        EXPECT_TRUE(_span == _ar1);
-        EXPECT_TRUE(_span == _ar2);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(_span == _ptr);
-#endif
-        EXPECT_TRUE(_span == _str);
-        EXPECT_TRUE(_span == _vec);
-        EXPECT_TRUE(_span == _sp);
-
-        EXPECT_TRUE(_ar == _span);
-        EXPECT_TRUE(_ar1 == _span);
-        EXPECT_TRUE(_ar2 == _span);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(_ptr == _span);
-#endif
-        EXPECT_TRUE(_str == _span);
-        EXPECT_TRUE(_vec == _span);
-        EXPECT_TRUE(_sp == _span);
-
-        // non-const span, const other type
-
-        EXPECT_TRUE(_span == "Hello");
-        EXPECT_TRUE(_span == ar);
-        EXPECT_TRUE(_span == ar1);
-        EXPECT_TRUE(_span == ar2);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(_span == ptr);
-#endif
-        EXPECT_TRUE(_span == str);
-        EXPECT_TRUE(_span == vec);
-        EXPECT_TRUE(_span == sp);
-
-        EXPECT_TRUE("Hello" == _span);
-        EXPECT_TRUE(ar == _span);
-        EXPECT_TRUE(ar1 == _span);
-        EXPECT_TRUE(ar2 == _span);
-#ifdef CONFIRM_COMPILATION_ERRORS
-        EXPECT_TRUE(ptr == _span);
-#endif
-        EXPECT_TRUE(str == _span);
-        EXPECT_TRUE(vec == _span);
-        EXPECT_TRUE(sp == _span);
-
-        // two spans
-
-        EXPECT_TRUE(_span == span);
-        EXPECT_TRUE(span == _span);
-    }
-
-    {
-        std::vector<char> str1 = {'H', 'e', 'l', 'l', 'o'};
-        cstring_span<> span1 = str1;
-        std::vector<char> str2 = std::move(str1);
-        cstring_span<> span2 = str2;
-
-        // comparison of spans from the same vector before and after move (ok)
-        EXPECT_TRUE(span1 == span2);
-    }
-}
-
-TEST(string_span_tests, ComparisonAndImplicitConstructors)
-{
-    {
-        cstring_span<> span = "Hello";
-
-        const char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        const char ar1[] = "Hello";
-        const char ar2[10] = "Hello";
-        const char* ptr = "Hello";
-        const std::string str = "Hello";
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-
-        // comparison to  literal
-        EXPECT_TRUE(span < cstring_span<>("Helloo"));
-        EXPECT_TRUE(span > cstring_span<>("Hell"));
-
-        // comparison to static array with no null termination
-        EXPECT_TRUE(span >= cstring_span<>(ar));
-
-        // comparison to static array with null at the end
-        EXPECT_TRUE(span <= cstring_span<>(ar1));
-
-        // comparison to static array with null in the middle
-        EXPECT_TRUE(span >= cstring_span<>(ar2));
-
-        // comparison to null-terminated c string
-        EXPECT_TRUE(span <= cstring_span<>(ptr, 5));
-
-        // comparison to string
-        EXPECT_TRUE(span >= cstring_span<>(str));
-
-        // comparison to vector of charaters with no null termination
-        EXPECT_TRUE(span <= cstring_span<>(vec));
-    }
-
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-
-        string_span<> span = ar;
-
-        char larr[] = "Hell";
-        char rarr[] = "Helloo";
-
-        char ar1[] = "Hello";
-        char ar2[10] = "Hello";
-        char* ptr = ar;
-        std::string str = "Hello";
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-
-        // comparison to static array with no null termination
-        EXPECT_TRUE(span <= string_span<>(ar));
-        EXPECT_TRUE(span < string_span<>(rarr));
-        EXPECT_TRUE(span > string_span<>(larr));
-
-        // comparison to static array with null at the end
-        EXPECT_TRUE(span >= string_span<>(ar1));
-
-        // comparison to static array with null in the middle
-        EXPECT_TRUE(span <= string_span<>(ar2));
-
-        // comparison to null-terminated c string
-        EXPECT_TRUE(span >= string_span<>(ptr, 5));
-
-        // comparison to string
-        EXPECT_TRUE(span <= string_span<>(str));
-
-        // comparison to vector of charaters with no null termination
-        EXPECT_TRUE(span >= string_span<>(vec));
-    }
-}
-
-TEST(string_span_tests, ConstrutorsEnsureZ)
-{
-    // remove z from literals
-    {
-        cstring_span<> sp = "hello";
-        EXPECT_TRUE(sp.length() == 5);
-    }
-
-    // take the string as is
-    {
-        auto str = std::string("hello");
-        cstring_span<> sp = str;
-        EXPECT_TRUE(sp.length() == 5);
-    }
-
-    // ensure z on c strings
-    {
-        gsl::owner<char*> ptr = new char[3];
-
-        ptr[0] = 'a';
-        ptr[1] = 'b';
-        ptr[2] = '\0';
-
-        string_span<> span = ensure_z(ptr);
-        EXPECT_TRUE(span.length() == 2);
-
-        delete[] ptr;
-    }
-}
-
-TEST(string_span_tests, Constructors)
-{
-    // creating cstring_span
-
-    // from span of a final extent
-    {
-        span<const char, 6> sp = "Hello";
-        cstring_span<> span = sp;
-        EXPECT_TRUE(span.length() == 6);
-    }
-
-// from const span of a final extent to non-const string_span
-#ifdef CONFIRM_COMPILATION_ERRORS
-    {
-        span<const char, 6> sp = "Hello";
-        string_span<> span = sp;
-        EXPECT_TRUE(span.length() == 6);
-    }
-#endif
-
-// from string temporary
-#ifdef CONFIRM_COMPILATION_ERRORS
-    {
-        cstring_span<> span = std::string("Hello");
-    }
-#endif
-
-    // default
-    {
-        cstring_span<> span;
-        EXPECT_TRUE(span.length() == 0);
-    }
-
-    // from string literal
-    {
-        cstring_span<> span = "Hello";
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const static array
-    {
-        const char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        cstring_span<> span = ar;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const static array
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        cstring_span<> span = ar;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const ptr and length
-    {
-        const char* ptr = "Hello";
-        cstring_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const ptr and length, include 0
-    {
-        const char* ptr = "Hello";
-        cstring_span<> span{ptr, 6};
-        EXPECT_TRUE(span.length() == 6);
-    }
-
-    // from const ptr and length, 0 inside
-    {
-        const char* ptr = "He\0lo";
-        cstring_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const ptr and length
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        char* ptr = ar;
-        cstring_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const ptr and length, 0 inside
-    {
-        char ar[] = {'H', 'e', '\0', 'l', 'o'};
-        char* ptr = ar;
-        cstring_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const string
-    {
-        const std::string str = "Hello";
-        const cstring_span<> span = str;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const string
-    {
-        std::string str = "Hello";
-        const cstring_span<> span = str;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const vector
-    {
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const cstring_span<> span = vec;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const vector
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const cstring_span<> span = vec;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const span
-    {
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const span<const char> inner = vec;
-        const cstring_span<> span = inner;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const span
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const span<char> inner = vec;
-        const cstring_span<> span = inner;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const string_span
-    {
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const cstring_span<> tmp = vec;
-        const cstring_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const string_span
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> tmp = vec;
-        cstring_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // creating string_span
-
-    // from string literal
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        string_span<> span = "Hello";
-#endif
-    }
-
-    // from const static array
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = ar;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const static array
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = ar;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const ptr and length
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const char* ptr = "Hello";
-        string_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const ptr and length
-    {
-        char ar[] = {'H', 'e', 'l', 'l', 'o'};
-        char* ptr = ar;
-        string_span<> span{ptr, 5};
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const string
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const std::string str = "Hello";
-        string_span<> span = str;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const string
-    {
-        std::string str = "Hello";
-        string_span<> span = str;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const vector
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = vec;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const vector
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = vec;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from const span
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const span<const char> inner = vec;
-        string_span<> span = inner;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const span
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        span<char> inner = vec;
-        string_span<> span = inner;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const span of non-const data from const vector
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const span<char> inner = vec;
-        string_span<> span = inner;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from const string_span
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        cstring_span<> tmp = vec;
-        string_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from non-const string_span
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const string_span<> tmp = vec;
-        const string_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-    }
-
-    // from non-const string_span from const vector
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        const std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> tmp = vec;
-        string_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-
-    // from const string_span of non-const data
-    {
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        const string_span<> tmp = vec;
-        const string_span<> span = tmp;
-        EXPECT_TRUE(span.length() == 5);
-    }
-}
-
-TEST(string_span_tests, MoveConstructors)
-{
-    // move string_span
-    {
-        cstring_span<> span = "Hello";
-        const auto span1 = std::move(span);
-        EXPECT_TRUE(span1.length() == 5);
-    }
-    {
-        cstring_span<> span = "Hello";
-        const auto span1 = move_wrapper(std::move(span));
-        EXPECT_TRUE(span1.length() == 5);
-    }
-    {
-        cstring_span<> span = "Hello";
-        const auto span1 = move_wrapper(std::move(span));
-        EXPECT_TRUE(span1.length() == 5);
-    }
-
-    // move span
-    {
-        span<const char> span = ensure_z("Hello");
-        const cstring_span<> span1 = std::move(span);
-        EXPECT_TRUE(span1.length() == 5);
-    }
-    {
-        span<const char> span = ensure_z("Hello");
-        const cstring_span<> span2 = move_wrapper(std::move(span));
-        EXPECT_TRUE(span2.length() == 5);
-    }
-
-    // move string
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::string str = "Hello";
-        string_span<> span = std::move(str);
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::string str = "Hello";
-        string_span<> span = move_wrapper<std::string>(std::move(str));
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        use<char>(create<string>());
-#endif
-    }
-
-    // move container
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = std::move(vec);
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        std::vector<char> vec = {'H', 'e', 'l', 'l', 'o'};
-        string_span<> span = move_wrapper<std::vector<char>>(std::move(vec));
-        EXPECT_TRUE(span.length() == 5);
-#endif
-    }
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        use<char>(create<std::vector<char>>());
-#endif
-    }
-}
-
-TEST(string_span_tests, Conversion)
-{
-#ifdef CONFIRM_COMPILATION_ERRORS
-    cstring_span<> span = "Hello";
-    cwstring_span<> wspan{span};
-    EXPECT_TRUE(wspan.length() == 5);
-#endif
-}
-
-TEST(string_span_tests, zstring)
-{
-    const auto terminateHandler = std::set_terminate([] {
-        std::cerr << "Expected Death. zstring";
-        std::abort();
-    });
-    const auto expected = GetExpectedDeathString(terminateHandler);
-
-    // create zspan from zero terminated string
-    {
-        char buf[1];
-        buf[0] = '\0';
-
-        zstring_span<> zspan({buf, 1});
-
-        EXPECT_TRUE(generic::strlen(zspan.assume_z()) == 0);
-        EXPECT_TRUE(zspan.as_string_span().size() == 0);
-        EXPECT_TRUE(zspan.ensure_z().size() == 0);
-    }
-
-    // create zspan from non-zero terminated string
-    {
-        char buf[1];
-        buf[0] = 'a';
-
-        auto workaround_macro = [&]() { const zstring_span<> zspan({buf, 1}); };
-        EXPECT_DEATH(workaround_macro(), expected);
-    }
-
-    // usage scenario: create zero-terminated temp file name and pass to a legacy API
-    {
-        char buf[10];
-
-        auto name = CreateTempName({buf, 10});
-        if (!name.empty())
-        {
-            czstring str = name.assume_z();
-            EXPECT_TRUE(generic::strlen(str) == 3);
-            EXPECT_TRUE(*(str + 3) == '\0');
-        }
-    }
-}
-
-TEST(string_span_tests, wzstring)
-{
-    const auto terminateHandler = std::set_terminate([] {
-        std::cerr << "Expected Death. wzstring";
-        std::abort();
-    });
-    const auto expected = GetExpectedDeathString(terminateHandler);
-
-    // create zspan from zero terminated string
-    {
-        wchar_t buf[1];
-        buf[0] = L'\0';
-
-        wzstring_span<> zspan({buf, 1});
-
-        EXPECT_TRUE(generic::strnlen(zspan.assume_z(), 1) == 0);
-        EXPECT_TRUE(zspan.as_string_span().size() == 0);
-        EXPECT_TRUE(zspan.ensure_z().size() == 0);
-    }
-
-    // create zspan from non-zero terminated string
-    {
-        wchar_t buf[1];
-        buf[0] = L'a';
-
-        const auto workaround_macro = [&]() { const wzstring_span<> zspan({buf, 1}); };
-        EXPECT_DEATH(workaround_macro(), expected);
-    }
-
-    // usage scenario: create zero-terminated temp file name and pass to a legacy API
-    {
-        wchar_t buf[10];
-
-        const auto name = CreateTempNameW({buf, 10});
-        if (!name.empty())
-        {
-            cwzstring str = name.assume_z();
-            EXPECT_TRUE(generic::strnlen(str, 10) == 3);
-            EXPECT_TRUE(*(str + 3) == L'\0');
-        }
-    }
-}
-
-TEST(string_span_tests, u16zstring)
-{
-    const auto terminateHandler = std::set_terminate([] {
-        std::cerr << "Expected Death. u16zstring";
-        std::abort();
-    });
-    const auto expected = GetExpectedDeathString(terminateHandler);
-
-    // create zspan from zero terminated string
-    {
-        char16_t buf[1];
-        buf[0] = L'\0';
-
-        u16zstring_span<> zspan({buf, 1});
-
-        EXPECT_TRUE(generic::strnlen(zspan.assume_z(), 1) == 0);
-        EXPECT_TRUE(zspan.as_string_span().size() == 0);
-        EXPECT_TRUE(zspan.ensure_z().size() == 0);
-    }
-
-    // create zspan from non-zero terminated string
-    {
-        char16_t buf[1];
-        buf[0] = u'a';
-
-        const auto workaround_macro = [&]() { const u16zstring_span<> zspan({buf, 1}); };
-        EXPECT_DEATH(workaround_macro(), expected);
-    }
-
-    // usage scenario: create zero-terminated temp file name and pass to a legacy API
-    {
-        char16_t buf[10];
-
-        const auto name = CreateTempNameU16({buf, 10});
-        if (!name.empty())
-        {
-            cu16zstring str = name.assume_z();
-            EXPECT_TRUE(generic::strnlen(str, 10) == 3);
-            EXPECT_TRUE(*(str + 3) == L'\0');
-        }
-    }
-}
-
-TEST(string_span_tests, u32zstring)
-{
-    const auto terminateHandler = std::set_terminate([] {
-        std::cerr << "Expected Death. u31zstring";
-        std::abort();
-    });
-    const auto expected = GetExpectedDeathString(terminateHandler);
-
-    // create zspan from zero terminated string
-    {
-        char32_t buf[1];
-        buf[0] = L'\0';
-
-        u32zstring_span<> zspan({buf, 1});
-
-        EXPECT_TRUE(generic::strnlen(zspan.assume_z(), 1) == 0);
-        EXPECT_TRUE(zspan.as_string_span().size() == 0);
-        EXPECT_TRUE(zspan.ensure_z().size() == 0);
-    }
-
-    // create zspan from non-zero terminated string
-    {
-        char32_t buf[1];
-        buf[0] = u'a';
-
-        const auto workaround_macro = [&]() { const u32zstring_span<> zspan({buf, 1}); };
-        EXPECT_DEATH(workaround_macro(), expected);
-    }
-
-    // usage scenario: create zero-terminated temp file name and pass to a legacy API
-    {
-        char32_t buf[10];
-
-        const auto name = CreateTempNameU32({buf, 10});
-        if (!name.empty())
-        {
-            cu32zstring str = name.assume_z();
-            EXPECT_TRUE(generic::strnlen(str, 10) == 3);
-            EXPECT_TRUE(*(str + 3) == L'\0');
-        }
-    }
-}
-
-TEST(string_span_tests, Issue305)
-{
-    std::map<gsl::cstring_span<>, int> foo = {{"foo", 0}, {"bar", 1}};
-    EXPECT_TRUE(foo["foo"] == 0);
-    EXPECT_TRUE(foo["bar"] == 1);
-}
-
-TEST(string_span_tests, char16_t_type)
-{
-    gsl::cu16string_span<> ss1 = gsl::ensure_z(u"abc");
-    EXPECT_TRUE(ss1.size() == 3);
-    EXPECT_TRUE(ss1.size_bytes() == 6);
-
-    std::u16string s1 = gsl::to_string(ss1);
-    EXPECT_TRUE(s1 == u"abc");
-
-    std::u16string s2 = u"abc";
-    gsl::u16string_span<> ss2 = s2;
-    EXPECT_TRUE(ss2.size() == 3);
-
-    gsl::u16string_span<> ss3 = ss2.subspan(1, 1);
-    EXPECT_TRUE(ss3.size() == 1);
-    EXPECT_TRUE(ss3[0] == u'b');
-
-    char16_t buf[4]{u'a', u'b', u'c', u'\0'};
-    gsl::u16string_span<> ss4{buf, 4};
-    EXPECT_TRUE(ss4[3] == u'\0');
-
-    gsl::cu16zstring_span<> ss5(u"abc");
-    EXPECT_TRUE((ss5.as_string_span().size()) == 3);
-
-    gsl::cu16string_span<> ss6 = ss5.as_string_span();
-    EXPECT_TRUE(ss6 == ss1);
-
-    std::vector<char16_t> v7 = {u'a', u'b', u'c'};
-    gsl::cu16string_span<> ss7{v7};
-    EXPECT_TRUE(ss7 == ss1);
-
-    gsl::cu16string_span<> ss8 = gsl::ensure_z(u"abc");
-    gsl::cu16string_span<> ss9 = gsl::ensure_z(u"abc");
-    EXPECT_TRUE(ss8 == ss9);
-
-    ss9 = gsl::ensure_z(u"abd");
-    EXPECT_TRUE(ss8 < ss9);
-    EXPECT_TRUE(ss8 <= ss9);
-    EXPECT_TRUE(ss8 != ss9);
-}
-
-TEST(string_span_tests, char32_t_type)
-{
-    gsl::cu32string_span<> ss1 = gsl::ensure_z(U"abc");
-    EXPECT_TRUE(ss1.size() == 3);
-    EXPECT_TRUE(ss1.size_bytes() == 12);
-
-    std::u32string s1 = gsl::to_string(ss1);
-    EXPECT_TRUE(s1 == U"abc");
-
-    std::u32string s2 = U"abc";
-    gsl::u32string_span<> ss2 = s2;
-    EXPECT_TRUE(ss2.size() == 3);
-
-    gsl::u32string_span<> ss3 = ss2.subspan(1, 1);
-    EXPECT_TRUE(ss3.size() == 1);
-    EXPECT_TRUE(ss3[0] == U'b');
-
-    char32_t buf[4]{U'a', U'b', U'c', U'\0'};
-    gsl::u32string_span<> ss4{buf, 4};
-    EXPECT_TRUE(ss4[3] == u'\0');
-
-    gsl::cu32zstring_span<> ss5(U"abc");
-    EXPECT_TRUE(ss5.as_string_span().size() == 3);
-
-    gsl::cu32string_span<> ss6 = ss5.as_string_span();
-    EXPECT_TRUE(ss6 == ss1);
-
-    gsl::cu32string_span<> ss8 = gsl::ensure_z(U"abc");
-    gsl::cu32string_span<> ss9 = gsl::ensure_z(U"abc");
-    EXPECT_TRUE(ss8 == ss9);
-
-    ss9 = gsl::ensure_z(U"abd");
-    EXPECT_TRUE(ss8 < ss9);
-    EXPECT_TRUE(ss8 <= ss9);
-    EXPECT_TRUE(ss8 != ss9);
-}
-
-TEST(string_span_tests, as_bytes)
-{
-    cwzstring_span<> v(L"qwerty");
-    const auto s = v.as_string_span();
-    const auto bs = as_bytes(s);
-    EXPECT_TRUE(static_cast<const void*>(bs.data()) == static_cast<const void*>(s.data()));
-    EXPECT_TRUE(bs.size() == s.size_bytes());
-}
-
-TEST(string_span_tests, as_writable_bytes)
-{
-    wchar_t buf[]{L"qwerty"};
-    wzstring_span<> v(buf);
-    const auto s = v.as_string_span();
-    const auto bs = as_writable_bytes(s);
-    EXPECT_TRUE(static_cast<const void*>(bs.data()) == static_cast<const void*>(s.data()));
-    EXPECT_TRUE(bs.size() == s.size_bytes());
-}