Make them meeting Cpp17NullablePointer

Author: frederick-vs-ja

libcxx/test/libcxx/containers/sequences/deque/abi.compile.pass.cpp

@@ -8,6 +8,7 @@
 
 // UNSUPPORTED: libcpp-abi-no-compressed-pair-padding
 
+#include <cstddef>
 #include <cstdint>
 #include <deque>
 #include <iterator>
@@ -28,6 +29,9 @@ class small_pointer {
   using pointer           = T*;
   using iterator_category = std::random_access_iterator_tag;
 
+  small_pointer() : offset() {}
+  small_pointer(std::nullptr_t) : offset() {}
+
   template <class CT,
             typename std::enable_if<std::is_same<const T, CT>::value && !std::is_const<T>::value, int>::type = 0>
   operator small_pointer<CT>() const;
@@ -41,6 +45,8 @@ class small_pointer {
                               int>::type = 0>
   operator small_pointer<CVoid>() const;
 
+  explicit operator bool() const;
+
   T& operator*() const;
   T* operator->() const;
   T& operator[](difference_type) const;
@@ -52,9 +58,9 @@ class small_pointer {
   small_pointer& operator+=(difference_type);
   small_pointer& operator-=(difference_type);
 
-  friend small_pointer operator+(small_pointer, difference_type) { return small_pointer{}; }
-  friend small_pointer operator+(difference_type, small_pointer) { return small_pointer{}; }
-  friend small_pointer operator-(small_pointer, difference_type) { return small_pointer{}; }
+  friend small_pointer operator+(small_pointer, difference_type) { return small_pointer(); }
+  friend small_pointer operator+(difference_type, small_pointer) { return small_pointer(); }
+  friend small_pointer operator-(small_pointer, difference_type) { return small_pointer(); }
   friend difference_type operator-(small_pointer, small_pointer) { return 0; }
 
   friend bool operator==(small_pointer, small_pointer) { return true; }
@@ -66,6 +72,13 @@ class small_pointer {
   friend bool operator>(small_pointer, small_pointer) { return false; }
   friend bool operator>=(small_pointer, small_pointer) { return true; }
 
+  friend bool operator==(small_pointer, std::nullptr_t) { return true; }
+#if TEST_STD_VER < 20
+  friend bool operator==(std::nullptr_t, small_pointer) { return true; }
+  friend bool operator!=(small_pointer, std::nullptr_t) { return false; }
+  friend bool operator!=(std::nullptr_t, small_pointer) { return false; }
+#endif
+
   small_pointer pointer_to(T&);
 };
 
@@ -74,19 +87,43 @@ class small_pointer<const void> {
   std::uint16_t offset;
 
 public:
+  small_pointer() : offset() {}
+  small_pointer(std::nullptr_t) : offset() {}
+
   template <class CT, typename std::enable_if<std::is_convertible<CT*, const void*>::value, int>::type = 0>
   explicit operator small_pointer<CT>() const;
+
+  explicit operator bool() const;
+
+  friend bool operator==(small_pointer, std::nullptr_t) { return true; }
+#if TEST_STD_VER < 20
+  friend bool operator==(std::nullptr_t, small_pointer) { return true; }
+  friend bool operator!=(small_pointer, std::nullptr_t) { return false; }
+  friend bool operator!=(std::nullptr_t, small_pointer) { return false; }
+#endif
 };
 
 template <>
 class small_pointer<void*> {
   std::uint16_t offset;
 
 public:
+  small_pointer() : offset() {}
+  small_pointer(std::nullptr_t) : offset() {}
+
   operator small_pointer<const void>() const;
 
   template <class T, typename std::enable_if<std::is_convertible<T*, void*>::value, int>::type = 0>
   explicit operator small_pointer<T>() const;
+
+  explicit operator bool() const;
+
+  friend bool operator==(small_pointer, std::nullptr_t) { return true; }
+#if TEST_STD_VER < 20
+  friend bool operator==(std::nullptr_t, small_pointer) { return true; }
+  friend bool operator!=(small_pointer, std::nullptr_t) { return false; }
+  friend bool operator!=(std::nullptr_t, small_pointer) { return false; }
+#endif
 };
 
 template <class T>