LWG-3769 basic_const_iterator::operator== causes infinite constrain…

…t recursion (#3459)
microsoft · Feb 14, 2023 · be588ec · be588ec
1 parent 6b2fef2
commit be588ec
Showing 1 changed file with 36 additions and 40 deletions.
diff --git a/stl/inc/xutility b/stl/inc/xutility
@@ -1932,72 +1932,74 @@ public:
     }
 
     template <sentinel_for<_Iter> _Sent>
-    _NODISCARD constexpr bool operator==(const _Sent& _Se) const // per LWG-3769
+    _NODISCARD constexpr bool operator==(const _Sent& _Se) const
         noexcept(noexcept(_Fake_copy_init<bool>(_Current == _Se))) /* strengthened */ {
         return _Current == _Se;
     }
 
-    _NODISCARD_FRIEND constexpr bool
-        operator<(const basic_const_iterator& _Left, const basic_const_iterator& _Right) noexcept(
-            noexcept(_Fake_copy_init<bool>(_Left._Current < _Right._Current))) // strengthened
+    _NODISCARD constexpr bool operator<(const basic_const_iterator& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current < _Right._Current))) // strengthened
         requires random_access_iterator<_Iter>
     {
-        return _Left._Current < _Right._Current;
+        return _Current < _Right._Current;
     }
 
-    _NODISCARD_FRIEND constexpr bool
-        operator>(const basic_const_iterator& _Left, const basic_const_iterator& _Right) noexcept(
-            noexcept(_Fake_copy_init<bool>(_Left._Current > _Right._Current))) // strengthened
+    _NODISCARD constexpr bool operator>(const basic_const_iterator& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current > _Right._Current))) // strengthened
         requires random_access_iterator<_Iter>
     {
-        return _Left._Current > _Right._Current;
+        return _Current > _Right._Current;
     }
 
-    _NODISCARD_FRIEND constexpr bool
-        operator<=(const basic_const_iterator& _Left, const basic_const_iterator& _Right) noexcept(
-            noexcept(_Fake_copy_init<bool>(_Left._Current <= _Right._Current))) // strengthened
+    _NODISCARD constexpr bool operator<=(const basic_const_iterator& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current <= _Right._Current))) // strengthened
         requires random_access_iterator<_Iter>
     {
-        return _Left._Current <= _Right._Current;
+        return _Current <= _Right._Current;
     }
 
-    _NODISCARD_FRIEND constexpr bool
-        operator>=(const basic_const_iterator& _Left, const basic_const_iterator& _Right) noexcept(
-            noexcept(_Fake_copy_init<bool>(_Left._Current >= _Right._Current))) // strengthened
+    _NODISCARD constexpr bool operator>=(const basic_const_iterator& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current >= _Right._Current))) // strengthened
         requires random_access_iterator<_Iter>
     {
-        return _Left._Current >= _Right._Current;
+        return _Current >= _Right._Current;
     }
 
-    _NODISCARD_FRIEND constexpr auto operator<=>(const basic_const_iterator& _Left,
-        const basic_const_iterator& _Right) noexcept(noexcept(_Left._Current <=> _Right._Current)) // strengthened
+    _NODISCARD constexpr auto operator<=>(const basic_const_iterator& _Right) const
+        noexcept(noexcept(_Current <=> _Right._Current)) // strengthened
         requires random_access_iterator<_Iter> && three_way_comparable<_Iter>
     {
-        return _Left._Current <=> _Right._Current;
+        return _Current <=> _Right._Current;
     }
 
     template <_Bci_order<_Iter> _Other>
-    _NODISCARD_FRIEND constexpr bool operator<(const basic_const_iterator& _Left, const _Other& _Right) noexcept(
-        noexcept(_Fake_copy_init<bool>(_Left._Current < _Right))) /* strengthened */ {
-        return _Left._Current < _Right;
+    _NODISCARD constexpr bool operator<(const _Other& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current < _Right))) /* strengthened */ {
+        return _Current < _Right;
     }
 
     template <_Bci_order<_Iter> _Other>
-    _NODISCARD_FRIEND constexpr bool operator>(const basic_const_iterator& _Left, const _Other& _Right) noexcept(
-        noexcept(_Fake_copy_init<bool>(_Left._Current > _Right))) /* strengthened */ {
-        return _Left._Current > _Right;
+    _NODISCARD constexpr bool operator>(const _Other& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current > _Right))) /* strengthened */ {
+        return _Current > _Right;
     }
 
     template <_Bci_order<_Iter> _Other>
-    _NODISCARD_FRIEND constexpr bool operator<=(const basic_const_iterator& _Left, const _Other& _Right) noexcept(
-        noexcept(_Fake_copy_init<bool>(_Left._Current <= _Right))) /* strengthened */ {
-        return _Left._Current <= _Right;
+    _NODISCARD constexpr bool operator<=(const _Other& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current <= _Right))) /* strengthened */ {
+        return _Current <= _Right;
     }
 
     template <_Bci_order<_Iter> _Other>
-    _NODISCARD_FRIEND constexpr bool operator>=(const basic_const_iterator& _Left, const _Other& _Right) noexcept(
-        noexcept(_Fake_copy_init<bool>(_Left._Current >= _Right))) /* strengthened */ {
-        return _Left._Current >= _Right;
+    _NODISCARD constexpr bool operator>=(const _Other& _Right) const
+        noexcept(noexcept(_Fake_copy_init<bool>(_Current >= _Right))) /* strengthened */ {
+        return _Current >= _Right;
+    }
+
+    template <_Bci_order_3way<_Iter> _Other>
+    _NODISCARD constexpr auto operator<=>(const _Other& _Right) const
+        noexcept(noexcept(_Current <=> _Right)) /* strengthened */ {
+        return _Current <=> _Right;
     }
 
     template <_Not_bci_order<_Iter> _Other>
@@ -2024,12 +2026,6 @@ public:
         return _Left >= _Right._Current;
     }
 
-    template <_Bci_order_3way<_Iter> _Other>
-    _NODISCARD_FRIEND constexpr auto operator<=>(const basic_const_iterator& _Left, const _Other& _Right) noexcept(
-        noexcept(_Left._Current <=> _Right)) /* strengthened */ {
-        return _Left._Current <=> _Right;
-    }
-
     _NODISCARD_FRIEND constexpr basic_const_iterator operator+(const basic_const_iterator& _It,
         const difference_type _Off) noexcept(noexcept(basic_const_iterator{_It._Current + _Off})) // strengthened
         requires random_access_iterator<_Iter>
@@ -2052,15 +2048,15 @@ public:
     }
 
     template <sized_sentinel_for<_Iter> _Sent>
-    _NODISCARD constexpr difference_type operator-(const _Sent& _Se) const // per LWG-3769
+    _NODISCARD constexpr difference_type operator-(const _Sent& _Se) const
         noexcept(noexcept(_Current - _Se)) /* strengthened */ {
         return _Current - _Se;
     }
 
     template <_Not_a_const_iterator _Sent>
         requires sized_sentinel_for<_Sent, _Iter>
     _NODISCARD_FRIEND constexpr difference_type operator-(const _Sent& _Se, const basic_const_iterator& _It) noexcept(
-        noexcept(_Se - _It._Current)) /* strengthened */ { // per LWG-3769
+        noexcept(_Se - _It._Current)) /* strengthened */ {
         return _Se - _It._Current;
     }
 };