On Fri, 10 Jul 2026 at 08:04, Tomasz Kamiński <[email protected]> wrote: > > 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. > --- > Testing on x86_64-linux. *repeat* test passed. > OK for trunk when all test passes? > > libstdc++-v3/include/std/ranges | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges > index 39a50b03e45..ea69a6c8dee 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 +7939,12 @@ 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))) > - { } > + { > + // _GLIBCXX_RESOLVE_LIB_DEFECTS > + // 3772. repeat_view's piecewise constructor is missing Postconditions
We don't need the comment because this is a C++23 feature and the LWG issue was resolved before publication of the C++23 standard. So this is just what the C++23 standard says, not a defect against C++23 that was resolved later. OK for trunk and gcc-16 without the comment, thanks. > + if constexpr (__detail::__is_signed_integer_like<_Bound>) > + __glibcxx_assert(_M_bound >= 0); > + } > > constexpr _Iterator > begin() const > -- > 2.54.0 >
