https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93267
Bug ID: 93267
Summary: std::ranges::begin|end do not work for iota_view when
the element and bound type are the same
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: pilarlatiesa at gmail dot com
Target Milestone: ---
The following testcase emits errors at the specified locations:
#include <cstddef>
#include <ranges>
int main()
{
std::size_t const Zero = 0u;
std::size_t const Size = 10u;
auto const Test1 = std::ranges::views::iota(0, Size);
auto beginTest1 = std::ranges::begin(Test1); // OK
auto const Test2 = std::ranges::views::iota(Zero, Size);
auto beginTest2 = std::ranges::begin(Test2); // Error
std::ranges::iota_view const Test3(Zero, Size);
auto beginTest3 = std::ranges::begin(Test3); // Error
std::ranges::iota_view<std::size_t, std::size_t> const Test4(0, Size);
auto beginTest4 = std::ranges::begin(Test4); // Error
std::ranges::iota_view<int, std::size_t> const Test5(0, Size);
auto beginTest4 = std::ranges::begin(Test5); // OK
}
The error reads:
error: no match for call to '(const std::ranges::__cust_access::_Begin) (const
std::ranges::iota_view<long unsigned int, long unsigned int>&)'
/home/pililatiesa/gcc-trunk-20200114/include/c++/10.0.0/bits/range_access.h:420:2:
note: candidate: 'constexpr auto
std::ranges::__cust_access::_Begin::operator()(_Tp&&) const [with _Tp = const
std::ranges::iota_view<long unsigned int, long unsigned int>&]'
420 | operator()(_Tp&& __t) const noexcept(_S_noexcept<_Tp>())
| ^~~~~~~~
/home/pililatiesa/gcc-trunk-20200114/include/c++/10.0.0/bits/range_access.h:420:2:
note: constraints not satisfied
<source>: In instantiation of 'constexpr auto
std::ranges::__cust_access::_Begin::operator()(_Tp&&) const [with _Tp = const
std::ranges::iota_view<long unsigned int, long unsigned int>&]':
<source>:10:34: required from here
/home/pililatiesa/gcc-trunk-20200114/include/c++/10.0.0/bits/range_access.h:420:2:
required by the constraints of 'template<class _Tp> requires
(__maybe_safe_range<_Tp>) && ((is_array_v<typename
std::remove_reference<_Tp>::remove_reference_t>) || (__member_begin<_Tp>) ||
(__adl_begin<_Tp>)) constexpr auto
std::ranges::__cust_access::_Begin::operator()(_Tp&&) const'
/home/pililatiesa/gcc-trunk-20200114/include/c++/10.0.0/bits/range_access.h:418:4:
note: neither operand of the disjunction is satisfied
418 | || __adl_begin<_Tp>
