[libc++] [NFC] Small cleanups in move_iterator.h

[• Quuxplusone]

Summary

Three NFC patches in one. The first two are completely mechanical; the third simply shuffles around some declarations so as to shrink the diff when C++20 move_iterator is finally implemented.

[libc++] Rename __i to __current_ in move_iterator. NFC.
[libc++] s/_LIBCPP_INLINE_VISIBILITY/_LIBCPP_HIDE_FROM_ABI/g in move_iterator.h. NFC.
[libc++] Further small cleanups of move_iterator.h. NFC.

[ldionne]

LGTM

libcxx/include/__iterator/move_iterator.h

 #endif
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Iter>
 class _LIBCPP_TEMPLATE_VIS move_iterator
 {
 public:
-    typedef _Iter                                            iterator_type;
+#if _LIBCPP_STD_VER > 17
+    typedef input_iterator_tag iterator_concept;
+#endif
+
+    typedef _Iter iterator_type;
+    typedef _If<
+        __is_cpp17_random_access_iterator<_Iter>::value,
+        random_access_iterator_tag,
+        typename iterator_traits<_Iter>::iterator_category
+    >  iterator_category;
     typedef typename iterator_traits<iterator_type>::value_type value_type;
     typedef typename iterator_traits<iterator_type>::difference_type difference_type;
     typedef iterator_type pointer;
-    typedef _If<__is_cpp17_random_access_iterator<_Iter>::value,
-        random_access_iterator_tag,
-        typename iterator_traits<_Iter>::iterator_category>  iterator_category;
-#if _LIBCPP_STD_VER > 17
-    typedef input_iterator_tag                               iterator_concept;
-#endif
 
 #ifndef _LIBCPP_CXX03_LANG
     typedef typename iterator_traits<iterator_type>::reference __reference;
     typedef typename conditional<
             is_reference<__reference>::value,
             typename remove_reference<__reference>::type&&,
             __reference
         >::type reference;
 #else
     typedef typename iterator_traits<iterator_type>::reference reference;
 #endif
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator() : __current_() {}
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    explicit move_iterator(_Iter __x) : __current_(__x) {}
+    explicit move_iterator(_Iter __i) : __current_(__i) {}
 
     template <class _Up, class = __enable_if_t<
-        !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
+        !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value
     > >
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}
 
     template <class _Up, class = __enable_if_t<
         !is_same<_Up, _Iter>::value &&
-        is_convertible<_Up const&, _Iter>::value &&
-        is_assignable<_Iter&, _Up const&>::value
+        is_convertible<const _Up&, _Iter>::value &&
+        is_assignable<_Iter&, const _Up&>::value
     > >
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator& operator=(const move_iterator<_Up>& __u) {
         __current_ = __u.base();
         return *this;
     }
 
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     _Iter base() const { return __current_; }
+
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     reference operator*() const { return static_cast<reference>(*__current_); }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    pointer  operator->() const { return __current_; }
+    pointer operator->() const { return __current_; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator[](difference_type __n) const { return static_cast<reference>(__current_[__n]); }
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator& operator++() { ++__current_; return *this; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    move_iterator  operator++(int) { move_iterator __tmp(*this); ++__current_; return __tmp; }
+    move_iterator operator++(int) { move_iterator __tmp(*this); ++__current_; return __tmp; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator& operator--() { --__current_; return *this; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    move_iterator  operator--(int) { move_iterator __tmp(*this); --__current_; return __tmp; }
+    move_iterator operator--(int) { move_iterator __tmp(*this); --__current_; return __tmp; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    move_iterator  operator+ (difference_type __n) const { return move_iterator(__current_ + __n); }
+    move_iterator operator+(difference_type __n) const { return move_iterator(__current_ + __n); }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator& operator+=(difference_type __n) { __current_ += __n; return *this; }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    move_iterator  operator- (difference_type __n) const { return move_iterator(__current_ - __n); }
+    move_iterator operator-(difference_type __n) const { return move_iterator(__current_ - __n); }
     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
     move_iterator& operator-=(difference_type __n) { __current_ -= __n; return *this; }
-    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-    reference operator[](difference_type __n) const { return static_cast<reference>(__current_[__n]); }
 
 private:
     _Iter __current_;
 };
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
     return __x.base() == __y.base();
 }
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
-    return __x.base() < __y.base();
+    return __x.base() != __y.base();
 }
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
-    return __x.base() != __y.base();
+    return __x.base() < __y.base();
 }
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
     return __x.base() > __y.base();
 }
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
-    return __x.base() >= __y.base();
+    return __x.base() <= __y.base();
 }
 
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-bool
-operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+bool operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
 {
-    return __x.base() <= __y.base();
+    return __x.base() >= __y.base();
 }
 
 #ifndef _LIBCPP_CXX03_LANG
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
-auto
-operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+auto operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
     -> decltype(__x.base() - __y.base())
 {
     return __x.base() - __y.base();
 }
 #else
 template <class _Iter1, class _Iter2>
 inline _LIBCPP_HIDE_FROM_ABI
 typename move_iterator<_Iter1>::difference_type
 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)