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huixie90 · huixie90 · commit f5289a142275 · 2024-10-19T10:21:10.000+01:00
diff --git a/libcxx/include/__iterator/prev.h b/libcxx/include/__iterator/prev.h
@@ -39,6 +39,9 @@ prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n)
   return __x;
 }
 
+// LWG 3197
+// It is unclear what the implications of "BidirectionalIterator" in the standard are.
+// However, calling std::prev(non-bidi-iterator) is obviously an error and we should catch it at compile time.
 template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0>
 [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _InputIter prev(_InputIter __it) {
   static_assert(__has_bidirectional_iterator_category<_InputIter>::value,

Original file line number	Diff line number	Diff line change
`@@ -39,6 +39,9 @@ prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n)`
`39`	`39`	`return __x;`
`40`	`40`	`}`
`41`	`41`
	`42`	`+// LWG 3197`
	`43`	`+// It is unclear what the implications of "BidirectionalIterator" in the standard are.`
	`44`	`+// However, calling std::prev(non-bidi-iterator) is obviously an error and we should catch it at compile time.`
`42`	`45`	`template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0>`
`43`	`46`	`[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _InputIter prev(_InputIter __it) {`
`44`	`47`	`static_assert(__has_bidirectional_iterator_category<_InputIter>::value,`