From 9b3ac8d681222a082231de712a4bd4299b658f11 Mon Sep 17 00:00:00 2001
From: Jordan Maples <jomaples@microsoft.com>
Date: Tue, 17 Mar 2020 15:02:00 -0700
Subject: [PATCH] discussed the issue with Casey Carter, the span ctor changes
 are accurate but the tests are not. The test require work that was done in
 C++17 regarding qualifier conversions to work correctly. Scoping tests for
 17.

---
 include/gsl/span                   | 19 +------------------
 tests/span_compatibility_tests.cpp |  6 ++++--
 2 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/include/gsl/span b/include/gsl/span
index 7c15eb4..469a2db 100644
--- a/include/gsl/span
+++ b/include/gsl/span
@@ -441,23 +441,6 @@ public:
         : storage_(KnownNotNull{arr + 0}, details::extent_type<N>())
     {}
 
-// #define useold
-#if defined(useold)
-    template <std::size_t N,
-              std::enable_if_t<details::is_allowed_extent_conversion<N, Extent>::value, int> = 0>
-    constexpr span(std::array<element_type, N>& arr) noexcept
-        : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
-    {}
-
-    template <std::size_t N,
-              std::enable_if_t<(details::is_allowed_extent_conversion<N, Extent>::value &&
-                                details::is_allowed_element_type_conversion<const value_type,
-                                                                            element_type>::value),
-                               int> = 0>
-    constexpr span(const std::array<value_type, N>& arr) noexcept
-        : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
-    {}
-#else
     template <class T, std::size_t N,
               std::enable_if_t<(details::is_allowed_extent_conversion<N, Extent>::value &&
                                 details::is_allowed_element_type_conversion<T, element_type>::value), int> = 0>
@@ -473,7 +456,7 @@ public:
     constexpr span(const std::array<T, N>& arr) noexcept
         : storage_(KnownNotNull{arr.data()}, details::extent_type<N>())
     {}
-#endif
+
     // NB: the SFINAE here uses .data() as an incomplete/imperfect proxy for the requirement
     // on Container to be a contiguous sequence container.
     template <class Container,
diff --git a/tests/span_compatibility_tests.cpp b/tests/span_compatibility_tests.cpp
index 1985f6f..acd85c5 100644
--- a/tests/span_compatibility_tests.cpp
+++ b/tests/span_compatibility_tests.cpp
@@ -48,20 +48,22 @@ TEST(span_compatibility_tests, assertion_tests)
     std::array<int, 3> stl{{100, 200, 300}};
     std::array<int*, 3> stl_nullptr{{nullptr,nullptr,nullptr}};
 
+#if __cplusplus >= 201703l
+    // This std::is_convertible_v<int*(*)[], int const* const(*)[]> fails for C++14
+    // so these conversions aren't valid in C++14
     {
         gsl::span<const int* const> sp_const_nullptr_1{stl_nullptr};
         EXPECT_TRUE(sp_const_nullptr_1.data() == stl_nullptr.data());
         EXPECT_TRUE(sp_const_nullptr_1.size() == 3);
 
-#if __cplusplus >= 201703l
         span<const int* const> sp_const_nullptr_2{std::as_const(stl_nullptr)};
         EXPECT_TRUE(sp_const_nullptr_2.data() == stl_nullptr.data());
         EXPECT_TRUE(sp_const_nullptr_2.size() == 3);
 
         static_assert(std::is_same<decltype(span{stl_nullptr}), span<int*, 3>);
         static_assert(std::is_same<decltype(span{std::as_const(stl_nullptr)}), span<int* const, 3>);
-#endif
     }
+#endif
 
     {
         gsl::span<int> sp_dyn;