diff --git a/include/gsl/span b/include/gsl/span
index 0d8dcb0..23c58c9 100644
--- a/include/gsl/span
+++ b/include/gsl/span
@@ -21,13 +21,10 @@
 #include <gsl/gsl_byte>   // for byte
 #include <gsl/gsl_util>   // for narrow_cast, narrow
 
-#include <algorithm> // for lexicographical_compare
 #include <array>     // for array
 #include <cstddef>   // for ptrdiff_t, size_t, nullptr_t
 #include <iterator>  // for reverse_iterator, distance, random_access_...
-#include <stdexcept>
 #include <type_traits> // for enable_if_t, declval, is_convertible, inte...
-#include <utility>
 
 #if defined(_MSC_VER) && !defined(__clang__)
 #pragma warning(push)
@@ -716,43 +713,6 @@ template <class ElementType, std::size_t Extent>
 constexpr const typename span<ElementType, Extent>::size_type span<ElementType, Extent>::extent;
 #endif
 
-// [span.comparison], span comparison operators
-template <class ElementType, std::size_t FirstExtent, std::size_t SecondExtent>
-constexpr bool operator==(span<ElementType, FirstExtent> l, span<ElementType, SecondExtent> r)
-{
-    return std::equal(l.begin(), l.end(), r.begin(), r.end());
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr bool operator!=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l == r);
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr bool operator<(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return std::lexicographical_compare(l.begin(), l.end(), r.begin(), r.end());
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr bool operator<=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l > r);
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr bool operator>(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return r < l;
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr bool operator>=(span<ElementType, Extent> l, span<ElementType, Extent> r)
-{
-    return !(l < r);
-}
-
 namespace details
 {
     // if we only supported compilers with good constexpr support then
@@ -796,123 +756,6 @@ as_writable_bytes(span<ElementType, Extent> s) noexcept
     return {reinterpret_cast<byte*>(s.data()), s.size_bytes()};
 }
 
-//
-// make_span() - Utility functions for creating spans
-//
-template <class ElementType>
-constexpr span<ElementType> make_span(ElementType* ptr, typename span<ElementType>::size_type count)
-{
-    return span<ElementType>(ptr, count);
-}
-
-template <class ElementType>
-constexpr span<ElementType> make_span(ElementType* firstElem, ElementType* lastElem)
-{
-    return span<ElementType>(firstElem, lastElem);
-}
-
-template <class ElementType, std::size_t N>
-constexpr span<ElementType, N> make_span(ElementType (&arr)[N]) noexcept
-{
-    return span<ElementType, N>(arr);
-}
-
-template <class Container>
-constexpr span<typename Container::value_type> make_span(Container& cont)
-{
-    return span<typename Container::value_type>(cont);
-}
-
-template <class Container>
-constexpr span<const typename Container::value_type> make_span(const Container& cont)
-{
-    return span<const typename Container::value_type>(cont);
-}
-
-template <class Ptr>
-constexpr span<typename Ptr::element_type> make_span(Ptr& cont, std::size_t count)
-{
-    return span<typename Ptr::element_type>(cont, count);
-}
-
-template <class Ptr>
-constexpr span<typename Ptr::element_type> make_span(Ptr& cont)
-{
-    return span<typename Ptr::element_type>(cont);
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr ElementType& at(span<ElementType, Extent> s, index i)
-{
-    // No bounds checking here because it is done in span::operator[] called below
-    Expects(i >= 0);
-    return s[static_cast<std::size_t>(i)];
-}
-
-// [span.obs] Free observer functions
-template <class ElementType, std::size_t Extent>
-constexpr std::ptrdiff_t ssize(const span<ElementType, Extent>& s) noexcept
-{
-    return static_cast<std::ptrdiff_t>(s.size());
-}
-
-// [span.iter] Free functions for begin/end functions
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::iterator
-begin(const span<ElementType, Extent>& s) noexcept
-{
-    return s.begin();
-}
-
-template <class ElementType, std::size_t Extent = dynamic_extent>
-constexpr typename span<ElementType, Extent>::iterator
-end(const span<ElementType, Extent>& s) noexcept
-{
-    return s.end();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::const_iterator
-cbegin(const span<ElementType, Extent>& s) noexcept
-{
-    return s.cbegin();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::const_iterator
-cend(const span<ElementType, Extent>& s) noexcept
-{
-    return s.cend();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::reverse_iterator
-rbegin(const span<ElementType, Extent>& s) noexcept
-{
-    return s.rbegin();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::reverse_iterator
-rend(const span<ElementType, Extent>& s) noexcept
-{
-    return s.rend();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::const_reverse_iterator
-crbegin(const span<ElementType, Extent>& s) noexcept
-{
-    return s.crbegin();
-}
-
-template <class ElementType, std::size_t Extent>
-constexpr typename span<ElementType, Extent>::const_reverse_iterator
-crend(const span<ElementType, Extent>& s) noexcept
-{
-    return s.crend();
-}
-
 } // namespace gsl
 
 #if defined(_MSC_VER) && !defined(__clang__)
diff --git a/include/gsl/span_ext b/include/gsl/span_ext
new file mode 100644
index 0000000..b466df8
--- /dev/null
+++ b/include/gsl/span_ext
@@ -0,0 +1,198 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// 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.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef GSL_SPAN_EXT_H
+#define GSL_SPAN_EXT_H
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// File: span_ext
+// Purpose: continue offering features that have been cut from the official
+//   implementation of span.
+//   While modernizing gsl::span a number of features needed to be removed to
+//   be compliant with the design of std::span
+//
+///////////////////////////////////////////////////////////////////////////////
+
+
+#include <gsl/gsl_util> // for narrow_cast, narrow
+#include <gsl/span>     // for span
+
+#include <algorithm> // for lexicographical_compare
+#include <cstddef>   // for ptrdiff_t, size_t
+#include <utility>
+
+namespace gsl
+{
+
+// [span.comparison], span comparison operators
+template <class ElementType, std::size_t FirstExtent, std::size_t SecondExtent>
+constexpr bool operator==(span<ElementType, FirstExtent> l, span<ElementType, SecondExtent> r)
+{
+    return std::equal(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator!=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l == r);
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator<(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return std::lexicographical_compare(l.begin(), l.end(), r.begin(), r.end());
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator<=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l > r);
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator>(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return r < l;
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr bool operator>=(span<ElementType, Extent> l, span<ElementType, Extent> r)
+{
+    return !(l < r);
+}
+
+//
+// make_span() - Utility functions for creating spans
+//
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* ptr, typename span<ElementType>::size_type count)
+{
+    return span<ElementType>(ptr, count);
+}
+
+template <class ElementType>
+constexpr span<ElementType> make_span(ElementType* firstElem, ElementType* lastElem)
+{
+    return span<ElementType>(firstElem, lastElem);
+}
+
+template <class ElementType, std::size_t N>
+constexpr span<ElementType, N> make_span(ElementType (&arr)[N]) noexcept
+{
+    return span<ElementType, N>(arr);
+}
+
+template <class Container>
+constexpr span<typename Container::value_type> make_span(Container& cont)
+{
+    return span<typename Container::value_type>(cont);
+}
+
+template <class Container>
+constexpr span<const typename Container::value_type> make_span(const Container& cont)
+{
+    return span<const typename Container::value_type>(cont);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont, std::size_t count)
+{
+    return span<typename Ptr::element_type>(cont, count);
+}
+
+template <class Ptr>
+constexpr span<typename Ptr::element_type> make_span(Ptr& cont)
+{
+    return span<typename Ptr::element_type>(cont);
+}
+
+// Specialization of gsl::at for span
+template <class ElementType, std::size_t Extent>
+constexpr ElementType& at(span<ElementType, Extent> s, index i)
+{
+    // No bounds checking here because it is done in span::operator[] called below
+    Ensures(i >= 0);
+    return s[narrow_cast<std::size_t>(i)];
+}
+
+// [span.obs] Free observer functions
+template <class ElementType, std::size_t Extent>
+constexpr std::ptrdiff_t ssize(const span<ElementType, Extent>& s) noexcept
+{
+    return static_cast<std::ptrdiff_t>(s.size());
+}
+
+// [span.iter] Free functions for begin/end functions
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::iterator
+begin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.begin();
+}
+
+template <class ElementType, std::size_t Extent = dynamic_extent>
+constexpr typename span<ElementType, Extent>::iterator
+end(const span<ElementType, Extent>& s) noexcept
+{
+    return s.end();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::const_iterator
+cbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.cbegin();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::const_iterator
+cend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.cend();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+rbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rbegin();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::reverse_iterator
+rend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.rend();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::const_reverse_iterator
+crbegin(const span<ElementType, Extent>& s) noexcept
+{
+    return s.crbegin();
+}
+
+template <class ElementType, std::size_t Extent>
+constexpr typename span<ElementType, Extent>::const_reverse_iterator
+crend(const span<ElementType, Extent>& s) noexcept
+{
+    return s.crend();
+}
+
+} // namespace gsl
+
+#endif // GSL_SPAN_EXT_H
diff --git a/include/gsl/string_span b/include/gsl/string_span
index cc0588e..2207291 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -19,7 +19,7 @@
 
 #include <gsl/gsl_assert> // for Ensures, Expects
 #include <gsl/gsl_util>   // for narrow_cast
-#include <gsl/span>       // for operator!=, operator==, dynamic_extent
+#include <gsl/span_ext>       // for operator!=, operator==, dynamic_extent
 
 #include <algorithm> // for equal, lexicographical_compare
 #include <array>     // for array
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 38dbb85..1099fda 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -153,6 +153,7 @@ function(add_gsl_test name)
 endfunction()
 
 add_gsl_test(span_tests)
+add_gsl_test(span_ext_tests)
 add_gsl_test(span_compatibility_tests)
 add_gsl_test(multi_span_tests)
 add_gsl_test(strided_span_tests)
diff --git a/tests/span_compatibility_tests.cpp b/tests/span_compatibility_tests.cpp
index 0301ace..8733e72 100644
--- a/tests/span_compatibility_tests.cpp
+++ b/tests/span_compatibility_tests.cpp
@@ -24,6 +24,7 @@
 #include <iterator>    // for reverse_iterator, operator-, operator==
 #include <type_traits> // for integral_constant<>::value, is_default_co...
 #include <utility>
+#include <vector>      // for vector
 
 using namespace std;
 using namespace gsl;
diff --git a/tests/span_ext_tests.cpp b/tests/span_ext_tests.cpp
new file mode 100644
index 0000000..bd256a8
--- /dev/null
+++ b/tests/span_ext_tests.cpp
@@ -0,0 +1,360 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+// 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/gsl_util> // for narrow_cast, at
+#include <gsl/span_ext> // for operator==, operator!=, make_span
+
+#include <array>       // for array
+#include <iostream>    // for cerr
+#include <vector>      // for vector
+
+using namespace std;
+using namespace gsl;
+
+namespace
+{
+static constexpr char deathstring[] = "Expected Death";
+} // namespace
+
+TEST(span_ext_test, make_span_from_pointer_length_constructor)
+{
+    std::set_terminate([] {
+        std::cerr << "Expected Death. from_pointer_length_constructor";
+        std::abort();
+    });
+    int arr[4] = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(&arr[0], 2);
+        EXPECT_TRUE(s.size() == 2);
+        EXPECT_TRUE(s.data() == &arr[0]);
+        EXPECT_TRUE(s[0] == 1);
+        EXPECT_TRUE(s[1] == 2);
+    }
+
+    {
+        int* p = nullptr;
+        auto s = make_span(p, narrow_cast<span<int>::size_type>(0));
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == nullptr);
+    }
+
+    {
+        int* p = nullptr;
+        auto workaround_macro = [=]() { make_span(p, 2); };
+        EXPECT_DEATH(workaround_macro(), deathstring);
+    }
+}
+
+TEST(span_ext_test, make_span_from_pointer_pointer_construction)
+{
+    int arr[4] = {1, 2, 3, 4};
+
+    {
+        auto s = make_span(&arr[0], &arr[2]);
+        EXPECT_TRUE(s.size() == 2);
+        EXPECT_TRUE(s.data() == &arr[0]);
+        EXPECT_TRUE(s[0] == 1);
+        EXPECT_TRUE(s[1] == 2);
+    }
+
+    {
+        auto s = make_span(&arr[0], &arr[0]);
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == &arr[0]);
+    }
+
+    {
+        int* p = nullptr;
+        auto s = make_span(p, p);
+        EXPECT_TRUE(s.size() == 0);
+        EXPECT_TRUE(s.data() == nullptr);
+    }
+}
+
+TEST(span_ext_test, make_span_from_array_constructor)
+ {
+     int arr[5] = {1, 2, 3, 4, 5};
+     int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
+     int arr3d[2][3][2] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
+
+     {
+         const auto s = make_span(arr);
+         EXPECT_TRUE(s.size() == 5);
+         EXPECT_TRUE(s.data() == std::addressof(arr[0]));
+     }
+
+     {
+         const auto s = make_span(std::addressof(arr2d[0]), 1);
+         EXPECT_TRUE(s.size() == 1);
+         EXPECT_TRUE(s.data() == std::addressof(arr2d[0]));
+     }
+
+     {
+         const auto s = make_span(std::addressof(arr3d[0]), 1);
+         EXPECT_TRUE(s.size() == 1);
+         EXPECT_TRUE(s.data() == std::addressof(arr3d[0]));
+     }
+ }
+
+ TEST(span_ext_test, make_span_from_dynamic_array_constructor)
+ {
+     double(*arr)[3][4] = new double[100][3][4];
+
+     {
+         auto s = make_span(&arr[0][0][0], 10);
+         EXPECT_TRUE(s.size() == 10);
+         EXPECT_TRUE(s.data() == &arr[0][0][0]);
+     }
+
+     delete[] arr;
+ }
+
+ TEST(span_ext_test, make_span_from_std_array_constructor)
+ {
+     std::array<int, 4> arr = {1, 2, 3, 4};
+
+     {
+         auto s = make_span(arr);
+         EXPECT_TRUE(s.size() == arr.size());
+         EXPECT_TRUE(s.data() == arr.data());
+     }
+
+     // This test checks for the bug found in gcc 6.1, 6.2, 6.3, 6.4, 6.5 7.1, 7.2, 7.3 - issue #590
+     {
+         span<int> s1 = make_span(arr);
+
+         static span<int> s2;
+         s2 = s1;
+
+ #if defined(__GNUC__) && __GNUC__ == 6 && (__GNUC_MINOR__ == 4 || __GNUC_MINOR__ == 5) &&          \
+     __GNUC_PATCHLEVEL__ == 0 && defined(__OPTIMIZE__)
+         // Known to be broken in gcc 6.4 and 6.5 with optimizations
+         // Issue in gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83116
+         EXPECT_TRUE(s1.size() == 4);
+         EXPECT_TRUE(s2.size() == 0);
+ #else
+         EXPECT_TRUE(s1.size() == s2.size());
+ #endif
+     }
+ }
+
+ TEST(span_ext_test, make_span_from_const_std_array_constructor)
+ {
+     const std::array<int, 4> arr = {1, 2, 3, 4};
+
+     {
+         auto s = make_span(arr);
+         EXPECT_TRUE(s.size() == arr.size());
+         EXPECT_TRUE(s.data() == arr.data());
+     }
+ }
+
+ TEST(span_ext_test, make_span_from_std_array_const_constructor)
+ {
+     std::array<const int, 4> arr = {1, 2, 3, 4};
+
+     {
+         auto s = make_span(arr);
+         EXPECT_TRUE(s.size() == arr.size());
+         EXPECT_TRUE(s.data() == arr.data());
+     }
+ }
+
+ TEST(span_ext_test, make_span_from_container_constructor)
+ {
+     std::vector<int> v = {1, 2, 3};
+     const std::vector<int> cv = v;
+
+     {
+         auto s = make_span(v);
+         EXPECT_TRUE(s.size() == v.size());
+         EXPECT_TRUE(s.data() == v.data());
+
+         auto cs = make_span(cv);
+         EXPECT_TRUE(cs.size() == cv.size());
+         EXPECT_TRUE(cs.data() == cv.data());
+     }
+ }
+
+ TEST(span_test, interop_with_gsl_at)
+ {
+     int arr[5] = {1, 2, 3, 4, 5};
+     span<int> s{arr};
+     EXPECT_TRUE(at(s, 0) ==  1);
+     EXPECT_TRUE(at(s, 1) == 2);
+ }
+
+ TEST(span_ext_test, iterator_free_functions)
+ {
+     int a[] = {1, 2, 3, 4};
+     span<int> s{a};
+
+     EXPECT_TRUE((std::is_same<decltype(s.begin()), decltype(begin(s))>::value));
+     EXPECT_TRUE((std::is_same<decltype(s.end()), decltype(end(s))>::value));
+
+     EXPECT_TRUE((std::is_same<decltype(s.cbegin()), decltype(cbegin(s))>::value));
+     EXPECT_TRUE((std::is_same<decltype(s.cend()), decltype(cend(s))>::value));
+
+     EXPECT_TRUE((std::is_same<decltype(s.rbegin()), decltype(rbegin(s))>::value));
+     EXPECT_TRUE((std::is_same<decltype(s.rend()), decltype(rend(s))>::value));
+
+     EXPECT_TRUE((std::is_same<decltype(s.crbegin()), decltype(crbegin(s))>::value));
+     EXPECT_TRUE((std::is_same<decltype(s.crend()), decltype(crend(s))>::value));
+
+     EXPECT_TRUE(s.begin() == begin(s));
+     EXPECT_TRUE(s.end() == end(s));
+
+     EXPECT_TRUE(s.cbegin() == cbegin(s));
+     EXPECT_TRUE(s.cend() == cend(s));
+
+     EXPECT_TRUE(s.rbegin() == rbegin(s));
+     EXPECT_TRUE(s.rend() == rend(s));
+
+     EXPECT_TRUE(s.crbegin() == crbegin(s));
+     EXPECT_TRUE(s.crend() == crend(s));
+ }
+
+ TEST(span_ext_test, ssize_free_function)
+ {
+     int a[] = {1, 2, 3, 4};
+     span<int> s{a};
+
+     EXPECT_FALSE((std::is_same<decltype(s.size()), decltype(ssize(s))>::value));
+     EXPECT_TRUE(s.size() == static_cast<std::size_t>(ssize(s)));
+ }
+
+  TEST(span_ext_test, comparison_operators)
+ {
+     {
+         span<int> s1;
+         span<int> s2;
+         EXPECT_TRUE(s1 == s2);
+         EXPECT_FALSE(s1 != s2);
+         EXPECT_FALSE(s1 < s2);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s1 >= s2);
+         EXPECT_TRUE(s2 == s1);
+         EXPECT_FALSE(s2 != s1);
+         EXPECT_FALSE(s2 != s1);
+         EXPECT_TRUE(s2 <= s1);
+         EXPECT_FALSE(s2 > s1);
+         EXPECT_TRUE(s2 >= s1);
+     }
+
+     {
+         int arr[] = {2, 1};
+         span<int> s1 = arr;
+         span<int> s2 = arr;
+
+         EXPECT_TRUE(s1 == s2);
+         EXPECT_FALSE(s1 != s2);
+         EXPECT_FALSE(s1 < s2);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s1 >= s2);
+         EXPECT_TRUE(s2 == s1);
+         EXPECT_FALSE(s2 != s1);
+         EXPECT_FALSE(s2 < s1);
+         EXPECT_TRUE(s2 <= s1);
+         EXPECT_FALSE(s2 > s1);
+         EXPECT_TRUE(s2 >= s1);
+     }
+
+     {
+         int arr[] = {2, 1}; // bigger
+
+         span<int> s1;
+         span<int> s2 = arr;
+
+         EXPECT_TRUE(s1 != s2);
+         EXPECT_TRUE(s2 != s1);
+         EXPECT_FALSE(s1 == s2);
+         EXPECT_FALSE(s2 == s1);
+         EXPECT_TRUE(s1 < s2);
+         EXPECT_FALSE(s2 < s1);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s2 <= s1);
+         EXPECT_TRUE(s2 > s1);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s2 >= s1);
+         EXPECT_FALSE(s1 >= s2);
+     }
+
+     {
+         int arr1[] = {1, 2};
+         int arr2[] = {1, 2};
+         span<int> s1 = arr1;
+         span<int> s2 = arr2;
+
+         EXPECT_TRUE(s1 == s2);
+         EXPECT_FALSE(s1 != s2);
+         EXPECT_FALSE(s1 < s2);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s1 >= s2);
+         EXPECT_TRUE(s2 == s1);
+         EXPECT_FALSE(s2 != s1);
+         EXPECT_FALSE(s2 < s1);
+         EXPECT_TRUE(s2 <= s1);
+         EXPECT_FALSE(s2 > s1);
+         EXPECT_TRUE(s2 >= s1);
+     }
+
+     {
+         int arr[] = {1, 2, 3};
+
+         span<int> s1 = {&arr[0], 2}; // shorter
+         span<int> s2 = arr;          // longer
+
+         EXPECT_TRUE(s1 != s2);
+         EXPECT_TRUE(s2 != s1);
+         EXPECT_FALSE(s1 == s2);
+         EXPECT_FALSE(s2 == s1);
+         EXPECT_TRUE(s1 < s2);
+         EXPECT_FALSE(s2 < s1);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s2 <= s1);
+         EXPECT_TRUE(s2 > s1);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s2 >= s1);
+         EXPECT_FALSE(s1 >= s2);
+     }
+
+     {
+         int arr1[] = {1, 2}; // smaller
+         int arr2[] = {2, 1}; // bigger
+
+         span<int> s1 = arr1;
+         span<int> s2 = arr2;
+
+         EXPECT_TRUE(s1 != s2);
+         EXPECT_TRUE(s2 != s1);
+         EXPECT_FALSE(s1 == s2);
+         EXPECT_FALSE(s2 == s1);
+         EXPECT_TRUE(s1 < s2);
+         EXPECT_FALSE(s2 < s1);
+         EXPECT_TRUE(s1 <= s2);
+         EXPECT_FALSE(s2 <= s1);
+         EXPECT_TRUE(s2 > s1);
+         EXPECT_FALSE(s1 > s2);
+         EXPECT_TRUE(s2 >= s1);
+         EXPECT_FALSE(s1 >= s2);
+     }
+ }
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index 2c4a19c..689fff9 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -196,27 +196,6 @@ TEST(span_test, from_pointer_length_constructor)
         auto workaround_macro = [=]() { const span<int> s{p, 2}; };
         EXPECT_DEATH(workaround_macro(), deathstring);
     }
-
-    {
-        auto s = make_span(&arr[0], 2);
-        EXPECT_TRUE(s.size() == 2);
-        EXPECT_TRUE(s.data() == &arr[0]);
-        EXPECT_TRUE(s[0] == 1);
-        EXPECT_TRUE(s[1] == 2);
-    }
-
-    {
-        int* p = nullptr;
-        auto s = make_span(p, narrow_cast<span<int>::size_type>(0));
-        EXPECT_TRUE(s.size() == 0);
-        EXPECT_TRUE(s.data() == nullptr);
-    }
-
-    {
-        int* p = nullptr;
-        auto workaround_macro = [=]() { make_span(p, 2); };
-        EXPECT_DEATH(workaround_macro(), deathstring);
-    }
 }
 
 TEST(span_test, from_pointer_pointer_construction)
@@ -283,27 +262,6 @@ TEST(span_test, from_pointer_pointer_construction)
     //    auto workaround_macro = [&]() { span<int> s{&arr[0], p}; };
     //    EXPECT_DEATH(workaround_macro(), deathstring);
     //}
-
-    {
-        auto s = make_span(&arr[0], &arr[2]);
-        EXPECT_TRUE(s.size() == 2);
-        EXPECT_TRUE(s.data() == &arr[0]);
-        EXPECT_TRUE(s[0] == 1);
-        EXPECT_TRUE(s[1] == 2);
-    }
-
-    {
-        auto s = make_span(&arr[0], &arr[0]);
-        EXPECT_TRUE(s.size() == 0);
-        EXPECT_TRUE(s.data() == &arr[0]);
-    }
-
-    {
-        int* p = nullptr;
-        auto s = make_span(p, p);
-        EXPECT_TRUE(s.size() == 0);
-        EXPECT_TRUE(s.data() == nullptr);
-    }
 }
 
 TEST(span_test, from_array_constructor)
@@ -393,24 +351,6 @@ TEST(span_test, from_array_constructor)
          EXPECT_TRUE(s.size() ==  1);
      }
 
-     {
-         const auto s = make_span(arr);
-         EXPECT_TRUE(s.size() == 5);
-         EXPECT_TRUE(s.data() == std::addressof(arr[0]));
-     }
-
-     {
-         const auto s = make_span(std::addressof(arr2d[0]), 1);
-         EXPECT_TRUE(s.size() == 1);
-         EXPECT_TRUE(s.data() == std::addressof(arr2d[0]));
-     }
-
-     {
-         const auto s = make_span(std::addressof(arr3d[0]), 1);
-         EXPECT_TRUE(s.size() == 1);
-         EXPECT_TRUE(s.data() == std::addressof(arr3d[0]));
-     }
-
      AddressOverloaded ao_arr[5] = {};
 
      {
@@ -430,12 +370,6 @@ TEST(span_test, from_array_constructor)
          EXPECT_TRUE(s.data() == &arr[0][0][0]);
      }
 
-     {
-         auto s = make_span(&arr[0][0][0], 10);
-         EXPECT_TRUE(s.size() == 10);
-         EXPECT_TRUE(s.data() == &arr[0][0][0]);
-     }
-
      delete[] arr;
  }
 
@@ -517,30 +451,6 @@ TEST(span_test, from_array_constructor)
          // try to take a temporary std::array
          take_a_span(get_an_array());
      }
-
-     {
-         auto s = make_span(arr);
-         EXPECT_TRUE(s.size() == arr.size());
-         EXPECT_TRUE(s.data() == arr.data());
-     }
-
-     // This test checks for the bug found in gcc 6.1, 6.2, 6.3, 6.4, 6.5 7.1, 7.2, 7.3 - issue #590
-     {
-         span<int> s1 = make_span(arr);
-
-         static span<int> s2;
-         s2 = s1;
-
- #if defined(__GNUC__) && __GNUC__ == 6 && (__GNUC_MINOR__ == 4 || __GNUC_MINOR__ == 5) &&          \
-     __GNUC_PATCHLEVEL__ == 0 && defined(__OPTIMIZE__)
-         // Known to be broken in gcc 6.4 and 6.5 with optimizations
-         // Issue in gcc: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83116
-         EXPECT_TRUE(s1.size() == 4);
-         EXPECT_TRUE(s2.size() == 0);
- #else
-         EXPECT_TRUE(s1.size() == s2.size());
- #endif
-     }
  }
 
  TEST(span_test, from_const_std_array_constructor)
@@ -591,12 +501,6 @@ TEST(span_test, from_array_constructor)
          // try to take a temporary std::array
          take_a_span(get_an_array());
      }
-
-     {
-         auto s = make_span(arr);
-         EXPECT_TRUE(s.size() == arr.size());
-         EXPECT_TRUE(s.data() == arr.data());
-     }
  }
 
  TEST(span_test, from_std_array_const_constructor)
@@ -636,12 +540,6 @@ TEST(span_test, from_array_constructor)
          span<int, 4> s{arr};
      }
  #endif
-
-     {
-         auto s = make_span(arr);
-         EXPECT_TRUE(s.size() == arr.size());
-         EXPECT_TRUE(s.data() == arr.data());
-     }
  }
 
  TEST(span_test, from_container_constructor)
@@ -730,16 +628,6 @@ TEST(span_test, from_array_constructor)
          span<int> s{m};
  #endif
      }
-
-     {
-         auto s = make_span(v);
-         EXPECT_TRUE(s.size() == v.size());
-         EXPECT_TRUE(s.data() == v.data());
-
-         auto cs = make_span(cv);
-         EXPECT_TRUE(cs.size() == cv.size());
-         EXPECT_TRUE(cs.data() == cv.data());
-     }
  }
 
  TEST(span_test, from_convertible_span_constructor){{span<DerivedClass> avd;
@@ -1004,46 +892,6 @@ TEST(span_test, from_array_constructor)
      span<int>::const_iterator cit3 = it + 4;
      EXPECT_TRUE(cit3 == s.cend());
  }
-
- TEST(span_test, iterator_free_functions)
- {
-     int a[] = {1, 2, 3, 4};
-     span<int> s{a};
-
-     EXPECT_TRUE((std::is_same<decltype(s.begin()), decltype(begin(s))>::value));
-     EXPECT_TRUE((std::is_same<decltype(s.end()), decltype(end(s))>::value));
-
-     EXPECT_TRUE((std::is_same<decltype(s.cbegin()), decltype(cbegin(s))>::value));
-     EXPECT_TRUE((std::is_same<decltype(s.cend()), decltype(cend(s))>::value));
-
-     EXPECT_TRUE((std::is_same<decltype(s.rbegin()), decltype(rbegin(s))>::value));
-     EXPECT_TRUE((std::is_same<decltype(s.rend()), decltype(rend(s))>::value));
-
-     EXPECT_TRUE((std::is_same<decltype(s.crbegin()), decltype(crbegin(s))>::value));
-     EXPECT_TRUE((std::is_same<decltype(s.crend()), decltype(crend(s))>::value));
-
-     EXPECT_TRUE(s.begin() == std::begin(s));
-     EXPECT_TRUE(s.end() == std::end(s));
-
-     EXPECT_TRUE(s.cbegin() == std::cbegin(s));
-     EXPECT_TRUE(s.cend() == std::cend(s));
-
-     EXPECT_TRUE(s.rbegin() == rbegin(s));
-     EXPECT_TRUE(s.rend() == rend(s));
-
-     EXPECT_TRUE(s.crbegin() == crbegin(s));
-     EXPECT_TRUE(s.crend() == crend(s));
- }
-
- TEST(span_test, ssize_free_function)
- {
-     int a[] = {1, 2, 3, 4};
-     span<int> s{a};
-
-     EXPECT_FALSE((std::is_same<decltype(s.size()), decltype(ssize(s))>::value));
-     EXPECT_TRUE(s.size() == static_cast<std::size_t>(ssize(s)));
- }
-
  TEST(span_test, iterator_comparisons)
  {
      int a[] = {1, 2, 3, 4};
@@ -1326,126 +1174,6 @@ TEST(span_test, from_array_constructor)
      }
  }
 
- TEST(span_test, comparison_operators)
- {
-     {
-         span<int> s1;
-         span<int> s2;
-         EXPECT_TRUE(s1 == s2);
-         EXPECT_FALSE(s1 != s2);
-         EXPECT_FALSE(s1 < s2);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s1 >= s2);
-         EXPECT_TRUE(s2 == s1);
-         EXPECT_FALSE(s2 != s1);
-         EXPECT_FALSE(s2 != s1);
-         EXPECT_TRUE(s2 <= s1);
-         EXPECT_FALSE(s2 > s1);
-         EXPECT_TRUE(s2 >= s1);
-     }
-
-     {
-         int arr[] = {2, 1};
-         span<int> s1 = arr;
-         span<int> s2 = arr;
-
-         EXPECT_TRUE(s1 == s2);
-         EXPECT_FALSE(s1 != s2);
-         EXPECT_FALSE(s1 < s2);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s1 >= s2);
-         EXPECT_TRUE(s2 == s1);
-         EXPECT_FALSE(s2 != s1);
-         EXPECT_FALSE(s2 < s1);
-         EXPECT_TRUE(s2 <= s1);
-         EXPECT_FALSE(s2 > s1);
-         EXPECT_TRUE(s2 >= s1);
-     }
-
-     {
-         int arr[] = {2, 1}; // bigger
-
-         span<int> s1;
-         span<int> s2 = arr;
-
-         EXPECT_TRUE(s1 != s2);
-         EXPECT_TRUE(s2 != s1);
-         EXPECT_FALSE(s1 == s2);
-         EXPECT_FALSE(s2 == s1);
-         EXPECT_TRUE(s1 < s2);
-         EXPECT_FALSE(s2 < s1);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s2 <= s1);
-         EXPECT_TRUE(s2 > s1);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s2 >= s1);
-         EXPECT_FALSE(s1 >= s2);
-     }
-
-     {
-         int arr1[] = {1, 2};
-         int arr2[] = {1, 2};
-         span<int> s1 = arr1;
-         span<int> s2 = arr2;
-
-         EXPECT_TRUE(s1 == s2);
-         EXPECT_FALSE(s1 != s2);
-         EXPECT_FALSE(s1 < s2);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s1 >= s2);
-         EXPECT_TRUE(s2 == s1);
-         EXPECT_FALSE(s2 != s1);
-         EXPECT_FALSE(s2 < s1);
-         EXPECT_TRUE(s2 <= s1);
-         EXPECT_FALSE(s2 > s1);
-         EXPECT_TRUE(s2 >= s1);
-     }
-
-     {
-         int arr[] = {1, 2, 3};
-
-         span<int> s1 = {&arr[0], 2}; // shorter
-         span<int> s2 = arr;          // longer
-
-         EXPECT_TRUE(s1 != s2);
-         EXPECT_TRUE(s2 != s1);
-         EXPECT_FALSE(s1 == s2);
-         EXPECT_FALSE(s2 == s1);
-         EXPECT_TRUE(s1 < s2);
-         EXPECT_FALSE(s2 < s1);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s2 <= s1);
-         EXPECT_TRUE(s2 > s1);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s2 >= s1);
-         EXPECT_FALSE(s1 >= s2);
-     }
-
-     {
-         int arr1[] = {1, 2}; // smaller
-         int arr2[] = {2, 1}; // bigger
-
-         span<int> s1 = arr1;
-         span<int> s2 = arr2;
-
-         EXPECT_TRUE(s1 != s2);
-         EXPECT_TRUE(s2 != s1);
-         EXPECT_FALSE(s1 == s2);
-         EXPECT_FALSE(s2 == s1);
-         EXPECT_TRUE(s1 < s2);
-         EXPECT_FALSE(s2 < s1);
-         EXPECT_TRUE(s1 <= s2);
-         EXPECT_FALSE(s2 <= s1);
-         EXPECT_TRUE(s2 > s1);
-         EXPECT_FALSE(s1 > s2);
-         EXPECT_TRUE(s2 >= s1);
-         EXPECT_FALSE(s1 >= s2);
-     }
- }
-
  TEST(span_test, as_bytes)
  {
      std::set_terminate([] {
@@ -1643,14 +1371,6 @@ TEST(span_test, from_array_constructor)
      EXPECT_TRUE(match[0].second == (f_it + 1));
  }
 
- TEST(span_test, interop_with_gsl_at)
- {
-     int arr[5] = {1, 2, 3, 4, 5};
-     span<int> s{arr};
-     EXPECT_TRUE(at(s, 0) ==  1);
-     EXPECT_TRUE(at(s, 1) == 2);
- }
-
  TEST(span_test, default_constructible)
  {
      EXPECT_TRUE((std::is_default_constructible<span<int>>::value));