From 2bdbba7418e5b06d100e77831135f8f45970a6cd Mon Sep 17 00:00:00 2001
From: Neil MacIntosh <neilmac@fb.com>
Date: Sat, 10 Feb 2018 19:21:22 -0800
Subject: [PATCH] Removed span from-nullptr_t ctor.

---
 include/gsl/span            |  2 --
 include/gsl/string_span     |  3 ---
 tests/span_tests.cpp        | 48 +++----------------------------------
 tests/string_span_tests.cpp |  6 -----
 4 files changed, 3 insertions(+), 56 deletions(-)

diff --git a/include/gsl/span b/include/gsl/span
index 2f076e0..51b46f2 100644
--- a/include/gsl/span
+++ b/include/gsl/span
@@ -341,8 +341,6 @@ public:
     {
     }
 
-    constexpr span(std::nullptr_t) GSL_NOEXCEPT : span() {}
-
     constexpr span(pointer ptr, index_type count) : storage_(ptr, count) {}
 
     constexpr span(pointer firstElem, pointer lastElem)
diff --git a/include/gsl/string_span b/include/gsl/string_span
index c56d136..42f8975 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -203,9 +203,6 @@ public:
     // move assign
     constexpr basic_string_span& operator=(basic_string_span&& other) GSL_NOEXCEPT = default;
 
-    // from nullptr
-    constexpr basic_string_span(std::nullptr_t ptr) GSL_NOEXCEPT : span_(ptr) {}
-
     constexpr basic_string_span(pointer ptr, index_type length) : span_(ptr, length) {}
     constexpr basic_string_span(pointer firstElem, pointer lastElem) : span_(firstElem, lastElem) {}
 
diff --git a/tests/span_tests.cpp b/tests/span_tests.cpp
index ebbf5ef..a71a228 100644
--- a/tests/span_tests.cpp
+++ b/tests/span_tests.cpp
@@ -94,48 +94,6 @@ TEST_CASE("size_optimization")
     }
 }
 
-TEST_CASE("from_nullptr_constructor")
-{
-    {
-        span<int> s = nullptr;
-        CHECK((s.size() == 0 && s.data() == nullptr));
-
-        span<const int> cs = nullptr;
-        CHECK((cs.size() == 0 && cs.data() == nullptr));
-    }
-
-    {
-        span<int, 0> s = nullptr;
-        CHECK((s.size() == 0 && s.data() == nullptr));
-
-        span<const int, 0> cs = nullptr;
-        CHECK((cs.size() == 0 && cs.data() == nullptr));
-    }
-
-    {
-#ifdef CONFIRM_COMPILATION_ERRORS
-        span<int, 1> s = nullptr;
-        CHECK((s.size() == 1 && s.data() == nullptr)); // explains why it can't compile
-#endif
-    }
-
-    {
-        span<int> s{nullptr};
-        CHECK((s.size() == 0 && s.data() == nullptr));
-
-        span<const int> cs{nullptr};
-        CHECK((cs.size() == 0 && cs.data() == nullptr));
-    }
-
-    {
-        span<int*> s{nullptr};
-        CHECK((s.size() == 0 && s.data() == nullptr));
-
-        span<const int*> cs{nullptr};
-        CHECK((cs.size() == 0 && cs.data() == nullptr));
-    }
-}
-
 TEST_CASE("from_nullptr_size_constructor")
 {
     {
@@ -1192,8 +1150,8 @@ TEST_CASE("crbegin_crend")
 TEST_CASE("comparison_operators")
 {
     {
-        span<int> s1 = nullptr;
-        span<int> s2 = nullptr;
+        span<int> s1;
+        span<int> s2;
         CHECK(s1 == s2);
         CHECK(!(s1 != s2));
         CHECK(!(s1 < s2));
@@ -1230,7 +1188,7 @@ TEST_CASE("comparison_operators")
     {
         int arr[] = {2, 1}; // bigger
 
-        span<int> s1 = nullptr;
+        span<int> s1;
         span<int> s2 = arr;
 
         CHECK(s1 != s2);
diff --git a/tests/string_span_tests.cpp b/tests/string_span_tests.cpp
index 83171ac..0032b0f 100644
--- a/tests/string_span_tests.cpp
+++ b/tests/string_span_tests.cpp
@@ -511,12 +511,6 @@ TEST_CASE("Constructors")
         CHECK(span.length() == 0);
     }
 
-    // from nullptr
-    {
-        cstring_span<> span(nullptr);
-        CHECK(span.length() == 0);
-    }
-
     // from string literal
     {
         cstring_span<> span = "Hello";