Bug 1625138 - Part 2: Replace mozilla::AddLvalueReference with std::add_lvalue_reference. r=froydnj

Differential Revision: https://phabricator.services.mozilla.com/D68356

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

mfbt/TypeTraits.h

@@ -752,40 +752,6 @@ namespace detail {
 
 enum Voidness { TIsVoid, TIsNotVoid };
 
-template <typename T, Voidness V = IsVoid<T>::value ? TIsVoid : TIsNotVoid>
-struct AddLvalueReferenceHelper;
-
-template <typename T>
-struct AddLvalueReferenceHelper<T, TIsVoid> {
-  typedef void Type;
-};
-
-template <typename T>
-struct AddLvalueReferenceHelper<T, TIsNotVoid> {
-  typedef T& Type;
-};
-
-}  // namespace detail
-
-/**
- * AddLvalueReference adds an lvalue & reference to T if one isn't already
- * present. (Note: adding an lvalue reference to an rvalue && reference in
- * essence replaces the && with a &&, per C+11 reference collapsing rules. For
- * example, int&& would become int&.)
- *
- * The final computed type will only *not* be an lvalue reference if T is void.
- *
- * mozilla::AddLvalueReference<int>::Type is int&;
- * mozilla::AddLvalueRference<volatile int&>::Type is volatile int&;
- * mozilla::AddLvalueReference<void*>::Type is void*&;
- * mozilla::AddLvalueReference<void>::Type is void;
- * mozilla::AddLvalueReference<struct S&&>::Type is struct S&.
- */
-template <typename T>
-struct AddLvalueReference : detail::AddLvalueReferenceHelper<T> {};
-
-namespace detail {
-
 template <typename T, Voidness V = IsVoid<T>::value ? TIsVoid : TIsNotVoid>
 struct AddRvalueReferenceHelper;
 

mfbt/UniquePtr.h

@@ -298,7 +298,7 @@ class UniquePtr {
     return *this;
   }
 
-  typename AddLvalueReference<T>::Type operator*() const { return *get(); }
+  std::add_lvalue_reference_t<T> operator*() const { return *get(); }
   Pointer operator->() const {
     MOZ_ASSERT(get(), "dereferencing a UniquePtr containing nullptr");
     return get();

mfbt/tests/TestTypeTraits.cpp

@@ -11,7 +11,6 @@
   test(type, __VA_ARGS__) test(const type, __VA_ARGS__) \
       test(volatile type, __VA_ARGS__) test(const volatile type, __VA_ARGS__)
 
-using mozilla::AddLvalueReference;
 using mozilla::AddPointer;
 using mozilla::AddRvalueReference;
 using mozilla::Decay;
@@ -410,18 +409,6 @@ static void TestIsConvertible() {
   //           "C doesn't convert to A (private inheritance)");
 }
 
-static_assert(IsSame<AddLvalueReference<int>::Type, int&>::value,
-              "not adding & to int correctly");
-static_assert(
-    IsSame<AddLvalueReference<volatile int&>::Type, volatile int&>::value,
-    "not adding & to volatile int& correctly");
-static_assert(IsSame<AddLvalueReference<void*>::Type, void*&>::value,
-              "not adding & to void* correctly");
-static_assert(IsSame<AddLvalueReference<void>::Type, void>::value,
-              "void shouldn't be transformed by AddLvalueReference");
-static_assert(IsSame<AddLvalueReference<struct S1&&>::Type, struct S1&>::value,
-              "not reference-collapsing struct S1&& & to struct S1& correctly");
-
 static_assert(IsSame<AddRvalueReference<int>::Type, int&&>::value,
               "not adding && to int correctly");
 static_assert(