https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111549
Bug ID: 111549
Summary: _RangeAdaptorClosure's (adaptor | adaptor) operator is
underconstrained
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: hewillk at gmail dot com
Target Milestone: ---
// Compose the adaptors __lhs and __rhs into a pipeline, returning
// another range adaptor closure object.
template<typename _Lhs, typename _Rhs>
requires __is_range_adaptor_closure<_Lhs>
&& __is_range_adaptor_closure<_Rhs>
constexpr auto
operator|(_Lhs __lhs, _Rhs __rhs)
{ return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
User-defined range adapter closure is not necessarily movable, in which case we
may need to constrain the pipe operator to avoid hard errors inside the
function.
#include <ranges>
struct Closure : std::ranges::range_adaptor_closure<Closure> {
Closure() = default;
Closure(Closure&&) = delete;
auto operator()(std::ranges::range auto&&) const;
};
int main() {
auto r = std::views::take(5) | Closure{};
}
https://godbolt.org/z/eqdvxxh3r
