https://gcc.gnu.org/g:168233d446e7b584debe4e8efa8719bbc3389ed1
commit r17-4777-g168233d446e7b584debe4e8efa8719bbc3389ed1 Author: Tomasz Kamiński <[email protected]> Date: Tue Sep 29 18:51:11 2026 +0200 libstdc++: Enable asserts in repeat_view::_Iterator uncoditionally. This implements LWG4624, "Inconsistent preconditions in repeat_view::iterator". The checks against _M_current being negive were disabled for cases where _Bound denotes unreachable_sentinel_t. However, _M_current has ptrdiff_t type in that case, and this check are as meaningfull are for integer bound. The assert in private _Iterator(const _Tp*, __index_type) constructor are removed entirelly, as the constructor can only be called internally. libstdc++-v3/ChangeLog: * include/std/ranges (repeat_view::_Iterator::_Iterator): Remove assert, as constructor is used only iternally. (repeat_view::_Iterator::operator--) (repeat_view::_Iterator::operator+=) (repeat_view::_Iterator::operator-=): Unconditionally assert on _M_current having non-negative value. Reviewed-by: Jonathan Wakely <[email protected]> Diff: --- libstdc++-v3/include/std/ranges | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 1c0991cae138..fe7c87b8f6ee 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -8075,10 +8075,7 @@ namespace views::__adaptor constexpr explicit _Iterator(const _Tp* __value, __index_type __bound = __index_type()) : _M_value(__value), _M_current(__bound) - { - if constexpr (!same_as<_Bound, unreachable_sentinel_t>) - __glibcxx_assert(__bound >= 0); - } + { } friend repeat_view; @@ -8112,8 +8109,9 @@ namespace views::__adaptor constexpr _Iterator& operator--() { - if constexpr (!same_as<_Bound, unreachable_sentinel_t>) - __glibcxx_assert(_M_current > 0); + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 4624. Inconsistent preconditions in repeat_view::iterator + __glibcxx_assert(_M_current > 0); --_M_current; return *this; } @@ -8129,8 +8127,7 @@ namespace views::__adaptor constexpr _Iterator& operator+=(difference_type __n) { - if constexpr (!same_as<_Bound, unreachable_sentinel_t>) - __glibcxx_assert(_M_current + __n >= 0); + __glibcxx_assert(_M_current + __n >= 0); _M_current += __n; return *this; } @@ -8138,8 +8135,7 @@ namespace views::__adaptor constexpr _Iterator& operator-=(difference_type __n) { - if constexpr (!same_as<_Bound, unreachable_sentinel_t>) - __glibcxx_assert(_M_current - __n >= 0); + __glibcxx_assert(_M_current - __n >= 0); _M_current -= __n; return *this; }
