diff options
Diffstat (limited to 'libcxx/include/__iterator/prev.h')
| -rw-r--r-- | libcxx/include/__iterator/prev.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/libcxx/include/__iterator/prev.h b/libcxx/include/__iterator/prev.h index 1651942acea9..2f0e6a088edb 100644 --- a/libcxx/include/__iterator/prev.h +++ b/libcxx/include/__iterator/prev.h @@ -27,8 +27,10 @@ _LIBCPP_BEGIN_NAMESPACE_STD template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _InputIter prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) { - _LIBCPP_ASSERT_UNCATEGORIZED(__n <= 0 || __has_bidirectional_iterator_category<_InputIter>::value, - "Attempt to prev(it, n) with a positive n on a non-bidirectional iterator"); + // Calling `advance` with a negative value on a non-bidirectional iterator is a no-op in the current implementation. + // Note that this check duplicates the similar check in `std::advance`. + _LIBCPP_ASSERT_PEDANTIC(__n <= 0 || __has_bidirectional_iterator_category<_InputIter>::value, + "Attempt to prev(it, n) with a positive n on a non-bidirectional iterator"); std::advance(__x, -__n); return __x; } |