https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111535
Bug ID: 111535
Summary: _RangeAdaptorClosure's (range | 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: ---
// range | adaptor is equivalent to adaptor(range).
template<typename _Self, typename _Range>
requires __is_range_adaptor_closure<_Self>
&& __adaptor_invocable<_Self, _Range>
constexpr auto
operator|(_Range&& __r, _Self&& __self)
{ return std::forward<_Self>(__self)(std::forward<_Range>(__r)); }
The pipe operator here does not constrain the Range template parameter, but the
range adaptor closure object requires arguments to model the range.
This makes libstdc++ accept the following
#include <ranges>
struct closure : std::ranges::range_adaptor_closure<closure> {
int operator()(int);
};
int main() {
auto r = 42 | closure{};
}
https://godbolt.org/z/hj9a68ssT
