https://gcc.gnu.org/g:c8c1f777617df6f1816900b779f32c80e016d7bd
commit r17-2305-gc8c1f777617df6f1816900b779f32c80e016d7bd Author: Tomasz Kamiński <[email protected]> Date: Fri Jul 10 08:43:02 2026 +0200 libstdc++: Validate bound consistently in repeat_view constructors. Add checks for bound being non-negative to _Tp&& __value and piecewise_construct_t constructor. The later resolves LWG3772, "repeat_view's piecewise constructor is missing Postconditions". We use __detail::__is_signed_integer_like<_Bound> as the condition for performing the check, to avoid checking it for unsigned integers for which it is trivially met. As _Bound is constrained to either unreachable_sentinel_t or integer-like, this gives equivalent behavior to standard specified !same_as<_Bound, unreachable_sentinel_t>. libstdc++-v3/ChangeLog: * include/std/ranges (repeat_view::repeat_view): Assert that __bound >= 0 consistently. Replace !same_as<unreachable_sentinel> with __is_signed_integer_like check. Reviewed-by: Jonathan Wakely <[email protected]> Signed-off-by: Tomasz Kamiński <[email protected]> Diff: --- libstdc++-v3/include/std/ranges | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 39a50b03e457..3e0df8d083c0 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -7918,14 +7918,17 @@ namespace views::__adaptor requires copy_constructible<_Tp> : _M_value(__value), _M_bound(__bound) { - if constexpr (!same_as<_Bound, unreachable_sentinel_t>) + if constexpr (__detail::__is_signed_integer_like<_Bound>) __glibcxx_assert(__bound >= 0); } constexpr explicit repeat_view(_Tp&& __value, _Bound __bound = _Bound()) : _M_value(std::move(__value)), _M_bound(__bound) - { } + { + if constexpr (__detail::__is_signed_integer_like<_Bound>) + __glibcxx_assert(__bound >= 0); + } template<typename... _Args, typename... _BoundArgs> requires constructible_from<_Tp, _Args...> @@ -7936,7 +7939,10 @@ namespace views::__adaptor tuple<_BoundArgs...> __bound_args = tuple<>{}) : _M_value(std::make_from_tuple<_Tp>(std::move(__args))), _M_bound(std::make_from_tuple<_Bound>(std::move(__bound_args))) - { } + { + if constexpr (__detail::__is_signed_integer_like<_Bound>) + __glibcxx_assert(_M_bound >= 0); + } constexpr _Iterator begin() const
