[libcxx-commits] [libcxx] [libc++] Implement P2988R12: `std::optional<T&>` (PR #155202)

[A. Jiang via libcxx-commits]

================
@@ -607,19 +613,19 @@ struct __is_std_optional : false_type {};
 template <class _Tp>
 struct __is_std_optional<optional<_Tp>> : true_type {};
 
-template <class _Tp>
-class _LIBCPP_DECLSPEC_EMPTY_BASES optional
-    : private __optional_move_assign_base<_Tp>,
-      private __optional_sfinae_ctor_base_t<_Tp>,
-      private __optional_sfinae_assign_base_t<_Tp> {
-  using __base _LIBCPP_NODEBUG = __optional_move_assign_base<_Tp>;
+template <class _Tp, class = void>
+struct __optional_iterator {};
 
-  using __pointer _LIBCPP_NODEBUG       = std::add_pointer_t<_Tp>;
-  using __const_pointer _LIBCPP_NODEBUG = std::add_pointer_t<const _Tp>;
+template <class _Tp>
+struct __optional_iterator<
+    _Tp,
+    enable_if_t<!(is_lvalue_reference_v<_Tp> && is_function_v<__libcpp_remove_reference_t<_Tp>>) &&
+                !(is_lvalue_reference_v<_Tp> && is_array_v<__libcpp_remove_reference_t<_Tp>>)> > {
+private:
+  using __pointer _LIBCPP_NODEBUG       = std::add_pointer_t<remove_reference_t<_Tp>>;
+  using __const_pointer _LIBCPP_NODEBUG = std::add_pointer_t<const remove_reference_t<_Tp>>;
----------------
frederick-vs-ja wrote:

Give we're touching this piece of code, let's drop (pre-existing) `std::` from type and variable names.
```suggestion
  using __pointer _LIBCPP_NODEBUG       = add_pointer_t<remove_reference_t<_Tp>>;
  using __const_pointer _LIBCPP_NODEBUG = add_pointer_t<const remove_reference_t<_Tp>>;
```

https://github.com/llvm/llvm-project/pull/155202