Bug 1625138 - Part 18: Replace mozilla::AddPointer with std::add_pointer. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D68373

--HG--
extra : moz-landing-system : lando

mfbt/Span.h

@@ -27,6 +27,7 @@
 #include <cstring>
 #include <iterator>
 #include <limits>
+#include <type_traits>
 #include <utility>
 
 #include "mozilla/Array.h"
@@ -76,8 +77,6 @@ template <class T>
 using remove_const_t = typename mozilla::RemoveConst<T>::Type;
 template <bool B, class T, class F>
 using conditional_t = typename mozilla::Conditional<B, T, F>::Type;
-template <class T>
-using add_pointer_t = typename mozilla::AddPointer<T>::Type;
 template <bool B, class T = void>
 using enable_if_t = typename mozilla::EnableIf<B, T>::Type;
 
@@ -122,7 +121,7 @@ class span_iterator {
   using difference_type = typename Span::index_type;
 
   using reference = conditional_t<IsConst, const element_type_, element_type_>&;
-  using pointer = add_pointer_t<reference>;
+  using pointer = std::add_pointer_t<reference>;
 
   constexpr span_iterator() : span_iterator(nullptr, 0) {}
 

mfbt/TypeTraits.h

@@ -476,21 +476,6 @@ template <typename T>
 struct RemovePointer
     : detail::RemovePointerHelper<T, typename RemoveCV<T>::Type> {};
 
-/**
- * Converts T& to T*. Otherwise returns T* given T. Note that C++17 wants
- * std::add_pointer to work differently for function types. We don't implement
- * that behavior here.
- *
- * mozilla::AddPointer<int> is int*;
- * mozilla::AddPointer<int*> is int**;
- * mozilla::AddPointer<int&> is int*;
- * mozilla::AddPointer<int* const> is int** const.
- */
-template <typename T>
-struct AddPointer {
-  typedef typename RemoveReference<T>::Type* Type;
-};
-
 /* 20.9.7.6 Other transformations [meta.trans.other] */
 
 /**

mfbt/tests/TestTypeTraits.cpp

@@ -7,7 +7,6 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/TypeTraits.h"
 
-using mozilla::AddPointer;
 using mozilla::AddRvalueReference;
 using mozilla::DeclVal;
 using mozilla::IsArray;
@@ -157,17 +156,6 @@ static_assert(IsSame<RemovePointer<bool TestRemovePointer::*>::Type,
                      bool TestRemovePointer::*>::value,
               "removing pointer from bool S::* must return bool S::*");
 
-static_assert(IsSame<AddPointer<int>::Type, int*>::value,
-              "adding pointer to int must return int*");
-static_assert(IsSame<AddPointer<int*>::Type, int**>::value,
-              "adding pointer to int* must return int**");
-static_assert(IsSame<AddPointer<int&>::Type, int*>::value,
-              "adding pointer to int& must return int*");
-static_assert(IsSame<AddPointer<int* const>::Type, int* const*>::value,
-              "adding pointer to int* const must return int* const*");
-static_assert(IsSame<AddPointer<int* volatile>::Type, int* volatile*>::value,
-              "adding pointer to int* volatile must return int* volatile*");
-
 /*
  * Android's broken [u]intptr_t inttype macros are broken because its PRI*PTR
  * macros are defined as "ld", but sizeof(long) is 8 and sizeof(intptr_t)