C++20 ranges/views are broken, via std::ranges::ref_view - iterator_concepts.h:980:13: error: no matching function for call to '__begin' #52696

db-src · 2021-12-14T17:13:52Z

It seems that range view adaptors don't work. The following example of trying to use ranges gives a pile of errors, seemingly related to ref_view being broken.

#include <algorithm>
#include <iostream>
#include <ranges>

static auto
odd(int const i)
{
    return (i & 1) == 1;
}
 
static auto
print(int const i)
{
    std::cout << i;
}

auto
main() -> int
{
    int const thenumbers[]{4, 8, 15, 16, 23, 42};
    std::ranges::for_each(thenumbers | std::views::filter(odd), print);
}

This is available on Compiler Explorer running Clang x86-64 trunk here: https://godbolt.org/z/7abh7rzaP - but the same happens in released version 13 there and on Debian

The same is true of the simple (recently edited, now compliant) example code from https://en.cppreference.com/w/cpp/ranges/transform_view ...

#include <algorithm>
#include <cstdio>
#include <iterator>
#include <ranges>
#include <string>
 
char rot13a(const char x, const char a)
{
    return a + (x - a + 13) % 26;
}
 
char rot13(const char x)
{
    if (x >= 'A' && x <= 'Z') {
        return rot13a(x, 'A');
    }
 
    if (x >= 'a' && x <= 'z') {
        return rot13a(x, 'a');
    }
 
    return x;
}
 
int main()
{
    auto show = [](const unsigned char x) { std::putchar(x); };
 
    std::string in{ "cppreference.com\n" };
    std::ranges::for_each(in, show);
    std::ranges::for_each(in | std::views::transform(rot13), show);
 
    std::string out;
    std::ranges::copy( std::views::transform(in, rot13), std::back_inserter(out) );
    std::ranges::for_each(out, show);
    std::ranges::for_each(out | std::views::transform(rot13), show);
}

... as can be seen on Compiler Explorer running Clang x86-64 trunk here - https://godbolt.org/z/xzdzjxaj4 ...

These are the errors from the 1st example:

In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:60:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/stl_algobase.h:65:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/stl_iterator_base_types.h:71:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:982:13: error: no matching function for call to '__begin'
        = decltype(ranges::__cust_access::__begin(std::declval<_Tp&>()));
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:595:5: note: in instantiation of template type alias '__range_iter_t' requested here
    using iterator_t = std::__detail::__range_iter_t<_Tp>;
    ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:121:36: note: in instantiation of template type alias 'iterator_t' requested here
      requires contiguous_iterator<iterator_t<_Derived>>
                                   ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<const int[6]>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<const int[6]>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: (skipping 20 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:21:38: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' required here
    std::ranges::for_each(thenumbers | std::views::filter(odd), print);
                                     ^
<source>:21:38: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:966:7: note: candidate template ignored: constraints not satisfied [with _Tp = std::ranges::ref_view<const int[6]>]
      __begin(_Tp& __t)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:16: note: because 'is_array_v<std::ranges::ref_view<const int[6]> >' evaluated to false
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:35: note: and 'std::ranges::ref_view<const int[6]> &' does not satisfy '__member_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:947:23: note: because '__decay_copy(__t.begin())' would be invalid: no member named 'begin' in 'std::ranges::ref_view<const int[6]>'
          { __decay_copy(__t.begin()) } -> input_or_output_iterator;
                             ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:59: note: and 'std::ranges::ref_view<const int[6]> &' does not satisfy '__adl_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                                          ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:958:19: note: because '__decay_copy(begin(__t))' would be invalid: call to deleted function 'begin'
          { __decay_copy(begin(__t)) } -> input_or_output_iterator;
                         ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:982:13: error: no matching function for call to '__begin'
        = decltype(ranges::__cust_access::__begin(std::declval<_Tp&>()));
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:595:5: note: in instantiation of template type alias '__range_iter_t' requested here
    using iterator_t = std::__detail::__range_iter_t<_Tp>;
    ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:127:25: note: in instantiation of template type alias 'iterator_t' requested here
        && contiguous_iterator<iterator_t<const _Derived>>
                               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<const int[6]>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<const int[6]>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: (skipping 20 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:21:38: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' required here
    std::ranges::for_each(thenumbers | std::views::filter(odd), print);
                                     ^
<source>:21:38: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:966:7: note: candidate template ignored: constraints not satisfied [with _Tp = const std::ranges::ref_view<const int[6]>]
      __begin(_Tp& __t)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:16: note: because 'is_array_v<const std::ranges::ref_view<const int[6]> >' evaluated to false
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:35: note: and 'const std::ranges::ref_view<const int[6]> &' does not satisfy '__member_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:947:23: note: because '__decay_copy(__t.begin())' would be invalid: no member named 'begin' in 'std::ranges::ref_view<const int[6]>'
          { __decay_copy(__t.begin()) } -> input_or_output_iterator;
                             ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:59: note: and 'const std::ranges::ref_view<const int[6]> &' does not satisfy '__adl_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                                          ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:958:19: note: because '__decay_copy(begin(__t))' would be invalid: call to deleted function 'begin'
          { __decay_copy(begin(__t)) } -> input_or_output_iterator;
                         ^
In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:63:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_algo.h:36:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:133:24: error: constraints not satisfied for alias template 'sentinel_t' [with _Range = std::ranges::ref_view<const int[6]>]
        && sized_sentinel_for<sentinel_t<_Derived>, iterator_t<_Derived>>
                              ^~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<const int[6]>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<const int[6]>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: while substituting template arguments into constraint expression here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1173:7: note: while checking the satisfaction of concept '__can_ref_view<const int (&)[6]>' requested here
          || __detail::__can_ref_view<_Range>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1173:17: note: (skipping 18 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
          || __detail::__can_ref_view<_Range>
                       ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:21:38: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' required here
    std::ranges::for_each(thenumbers | std::views::filter(odd), print);
                                     ^
<source>:21:38: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, const int (&)[6]>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:597:12: note: because 'std::ranges::ref_view<const int[6]>' does not satisfy 'range'
  template<range _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:585:2: note: because 'ranges::begin(__t)' would be invalid: no matching function for call to object of type 'const __cust_access::_Begin'
        ranges::begin(__t);
        ^
In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:63:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_algo.h:36:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:139:24: error: constraints not satisfied for alias template 'sentinel_t' [with _Range = const std::ranges::ref_view<const int[6]>]
        && sized_sentinel_for<sentinel_t<const _Derived>,
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:597:12: note: because 'const std::ranges::ref_view<const int[6]>' does not satisfy 'range'
  template<range _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:585:2: note: because 'ranges::begin(__t)' would be invalid: no matching function for call to object of type 'const __cust_access::_Begin'
        ranges::begin(__t);
        ^
<source>:21:38: error: invalid operands to binary expression ('const int[6]' and '_Partial<std::ranges::views::_Filter, decay_t<bool (&)(int)>>' (aka '_Partial<std::ranges::views::_Filter, bool (*)(int)>'))
    std::ranges::for_each(thenumbers | std::views::filter(odd), print);
                          ~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:858:7: note: candidate template ignored: constraints not satisfied [with _Self = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>, _Range = const int (&)[6]]
      operator|(_Range&& __r, _Self&& __self)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: because '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, _Bool (*)(int)>, const int (&)[6]>' evaluated to false
        && __adaptor_invocable<_Self, _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:20: note: because 'std::declval<_Adaptor>()(declval<_Args>()...)' would be invalid: no matching function for call to object of type 'std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>'
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
                   ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:867:7: note: candidate template ignored: constraints not satisfied [with _Lhs = const int *, _Rhs = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Filter, bool (*)(int)>]
      operator|(_Lhs __lhs, _Rhs __rhs)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:864:16: note: because 'derived_from<const int *, std::ranges::views::__adaptor::_RangeAdaptorClosure>' evaluated to false
      requires derived_from<_Lhs, _RangeAdaptorClosure>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/concepts:67:28: note: because '__is_base_of(std::ranges::views::__adaptor::_RangeAdaptorClosure, const int *)' evaluated to false
    concept derived_from = __is_base_of(_Base, _Derived)
                           ^
5 errors generated.
Compiler returned: 1

and 2nd:

In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:60:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/stl_algobase.h:65:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/stl_iterator_base_types.h:71:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:982:13: error: no matching function for call to '__begin'
        = decltype(ranges::__cust_access::__begin(std::declval<_Tp&>()));
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:595:5: note: in instantiation of template type alias '__range_iter_t' requested here
    using iterator_t = std::__detail::__range_iter_t<_Tp>;
    ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:121:36: note: in instantiation of template type alias 'iterator_t' requested here
      requires contiguous_iterator<iterator_t<_Derived>>
                                   ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<std::basic_string<char>>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<std::basic_string<char>>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: (skipping 20 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:31:30: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' required here
    std::ranges::for_each(in | std::views::transform(rot13), show);
                             ^
<source>:31:30: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:966:7: note: candidate template ignored: constraints not satisfied [with _Tp = std::ranges::ref_view<std::basic_string<char>>]
      __begin(_Tp& __t)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:16: note: because 'is_array_v<std::ranges::ref_view<std::basic_string<char> > >' evaluated to false
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:35: note: and 'std::ranges::ref_view<std::basic_string<char>> &' does not satisfy '__member_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:947:23: note: because '__decay_copy(__t.begin())' would be invalid: no member named 'begin' in 'std::ranges::ref_view<std::basic_string<char>>'
          { __decay_copy(__t.begin()) } -> input_or_output_iterator;
                             ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:59: note: and 'std::ranges::ref_view<std::basic_string<char>> &' does not satisfy '__adl_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                                          ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:958:19: note: because '__decay_copy(begin(__t))' would be invalid: call to deleted function 'begin'
          { __decay_copy(begin(__t)) } -> input_or_output_iterator;
                         ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:982:13: error: no matching function for call to '__begin'
        = decltype(ranges::__cust_access::__begin(std::declval<_Tp&>()));
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:595:5: note: in instantiation of template type alias '__range_iter_t' requested here
    using iterator_t = std::__detail::__range_iter_t<_Tp>;
    ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:127:25: note: in instantiation of template type alias 'iterator_t' requested here
        && contiguous_iterator<iterator_t<const _Derived>>
                               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<std::basic_string<char>>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<std::basic_string<char>>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: (skipping 20 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:31:30: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' required here
    std::ranges::for_each(in | std::views::transform(rot13), show);
                             ^
<source>:31:30: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:966:7: note: candidate template ignored: constraints not satisfied [with _Tp = const std::ranges::ref_view<std::basic_string<char>>]
      __begin(_Tp& __t)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:16: note: because 'is_array_v<const std::ranges::ref_view<std::basic_string<char> > >' evaluated to false
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:35: note: and 'const std::ranges::ref_view<std::basic_string<char>> &' does not satisfy '__member_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:947:23: note: because '__decay_copy(__t.begin())' would be invalid: no member named 'begin' in 'std::ranges::ref_view<std::basic_string<char>>'
          { __decay_copy(__t.begin()) } -> input_or_output_iterator;
                             ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:964:59: note: and 'const std::ranges::ref_view<std::basic_string<char>> &' does not satisfy '__adl_begin'
      requires is_array_v<_Tp> || __member_begin<_Tp&> || __adl_begin<_Tp&>
                                                          ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/iterator_concepts.h:958:19: note: because '__decay_copy(begin(__t))' would be invalid: call to deleted function 'begin'
          { __decay_copy(begin(__t)) } -> input_or_output_iterator;
                         ^
In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:63:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_algo.h:36:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:133:24: error: constraints not satisfied for alias template 'sentinel_t' [with _Range = std::ranges::ref_view<std::basic_string<char>>]
        && sized_sentinel_for<sentinel_t<_Derived>, iterator_t<_Derived>>
                              ^~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1097:29: note: in instantiation of template class 'std::ranges::view_interface<std::ranges::ref_view<std::basic_string<char>>>' requested here
    class ref_view : public view_interface<ref_view<_Range>>
                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of template class 'std::ranges::ref_view<std::basic_string<char>>' requested here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:38: note: in instantiation of requirement here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1151:27: note: while substituting template arguments into constraint expression here
        concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1173:7: note: while checking the satisfaction of concept '__can_ref_view<std::basic_string<char> &>' requested here
          || __detail::__can_ref_view<_Range>
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1173:17: note: (skipping 18 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
          || __detail::__can_ref_view<_Range>
                       ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:9: note: while substituting template arguments into constraint expression here
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while checking the satisfaction of concept '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: while substituting template arguments into constraint expression here
        && __adaptor_invocable<_Self, _Range>
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:31:30: note: while checking constraint satisfaction for template 'operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' required here
    std::ranges::for_each(in | std::views::transform(rot13), show);
                             ^
<source>:31:30: note: in instantiation of function template specialization 'std::ranges::views::__adaptor::operator|<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' requested here
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:597:12: note: because 'std::ranges::ref_view<std::basic_string<char>>' does not satisfy 'range'
  template<range _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:585:2: note: because 'ranges::begin(__t)' would be invalid: no matching function for call to object of type 'const __cust_access::_Begin'
        ranges::begin(__t);
        ^
In file included from <source>:1:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/algorithm:63:
In file included from /opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_algo.h:36:
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_util.h:139:24: error: constraints not satisfied for alias template 'sentinel_t' [with _Range = const std::ranges::ref_view<std::basic_string<char>>]
        && sized_sentinel_for<sentinel_t<const _Derived>,
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:597:12: note: because 'const std::ranges::ref_view<std::basic_string<char>>' does not satisfy 'range'
  template<range _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ranges_base.h:585:2: note: because 'ranges::begin(__t)' would be invalid: no matching function for call to object of type 'const __cust_access::_Begin'
        ranges::begin(__t);
        ^
<source>:31:30: error: invalid operands to binary expression ('std::string' (aka 'basic_string<char>') and '_Partial<std::ranges::views::_Transform, decay_t<char (&)(char)>>' (aka '_Partial<std::ranges::views::_Transform, char (*)(char)>'))
    std::ranges::for_each(in | std::views::transform(rot13), show);
                          ~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:87:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Fmtflags' for 1st argument
  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:130:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Openmode' for 1st argument
  operator|(_Ios_Openmode __a, _Ios_Openmode __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:170:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Iostate' for 1st argument
  operator|(_Ios_Iostate __a, _Ios_Iostate __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/cstddef:132:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::byte' for 1st argument
  operator|(byte __l, byte __r) noexcept
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:858:7: note: candidate template ignored: constraints not satisfied [with _Self = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, _Range = std::basic_string<char> &]
      operator|(_Range&& __r, _Self&& __self)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: because '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' evaluated to false
        && __adaptor_invocable<_Self, _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:20: note: because 'std::declval<_Adaptor>()(declval<_Args>()...)' would be invalid: no matching function for call to object of type 'std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>'
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
                   ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:867:7: note: candidate template ignored: constraints not satisfied [with _Lhs = std::basic_string<char>, _Rhs = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>]
      operator|(_Lhs __lhs, _Rhs __rhs)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:864:16: note: because 'derived_from<std::basic_string<char>, std::ranges::views::__adaptor::_RangeAdaptorClosure>' evaluated to false
      requires derived_from<_Lhs, _RangeAdaptorClosure>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/concepts:67:28: note: because '__is_base_of(std::ranges::views::__adaptor::_RangeAdaptorClosure, std::basic_string<char>)' evaluated to false
    concept derived_from = __is_base_of(_Base, _Derived)
                           ^
<source>:34:24: error: no matching function for call to object of type 'const std::ranges::views::_Transform'
    std::ranges::copy( std::views::transform(in, rot13), std::back_inserter(out) );
                       ^~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1975:2: note: candidate template ignored: constraints not satisfied [with _Range = std::basic_string<char> &, _Fp = char (&)(char)]
        operator() [[nodiscard]] (_Range&& __r, _Fp&& __f) const
        ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1973:21: note: because '__detail::__can_transform_view<std::basic_string<char> &, char (&)(char)>' evaluated to false
        requires __detail::__can_transform_view<_Range, _Fp>
                           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:1967:17: note: because 'transform_view(std::declval<_Range>(), std::declval<_Fp>())' would be invalid: no viable constructor or deduction guide for deduction of template arguments of 'transform_view'
          = requires { transform_view(std::declval<_Range>(), std::declval<_Fp>()); };
                       ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:890:2: note: candidate template ignored: constraints not satisfied [with _Args = <std::basic_string<char> &, char (&)(char)>]
        operator()(_Args&&... __args) const
        ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:888:11: note: because '__adaptor_partial_app_viable<std::ranges::views::_Transform, std::basic_string<char> &, char (&)(char)>' evaluated to false
        requires __adaptor_partial_app_viable<_Derived, _Args...>
                 ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:837:11: note: because 'sizeof...(_Args) == _Transform::_S_arity - 1' (2 == 1) evaluated to false
      && (sizeof...(_Args) == _Adaptor::_S_arity - 1)
          ^
<source>:36:31: error: invalid operands to binary expression ('std::string' (aka 'basic_string<char>') and '_Partial<std::ranges::views::_Transform, decay_t<char (&)(char)>>' (aka '_Partial<std::ranges::views::_Transform, char (*)(char)>'))
    std::ranges::for_each(out | std::views::transform(rot13), show);
                          ~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:87:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Fmtflags' for 1st argument
  operator|(_Ios_Fmtflags __a, _Ios_Fmtflags __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:130:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Openmode' for 1st argument
  operator|(_Ios_Openmode __a, _Ios_Openmode __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/bits/ios_base.h:170:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::_Ios_Iostate' for 1st argument
  operator|(_Ios_Iostate __a, _Ios_Iostate __b)
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/cstddef:132:3: note: candidate function not viable: no known conversion from 'std::string' (aka 'basic_string<char>') to 'std::byte' for 1st argument
  operator|(byte __l, byte __r) noexcept
  ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:858:7: note: candidate template ignored: constraints not satisfied [with _Self = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, _Range = std::basic_string<char> &]
      operator|(_Range&& __r, _Self&& __self)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:856:5: note: because '__adaptor_invocable<std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>, std::basic_string<char> &>' evaluated to false
        && __adaptor_invocable<_Self, _Range>
           ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:831:20: note: because 'std::declval<_Adaptor>()(declval<_Args>()...)' would be invalid: no matching function for call to object of type 'std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>'
      = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
                   ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:867:7: note: candidate template ignored: constraints not satisfied [with _Lhs = std::basic_string<char>, _Rhs = std::ranges::views::__adaptor::_Partial<std::ranges::views::_Transform, char (*)(char)>]
      operator|(_Lhs __lhs, _Rhs __rhs)
      ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/ranges:864:16: note: because 'derived_from<std::basic_string<char>, std::ranges::views::__adaptor::_RangeAdaptorClosure>' evaluated to false
      requires derived_from<_Lhs, _RangeAdaptorClosure>
               ^
/opt/compiler-explorer/gcc-snapshot/lib/gcc/x86_64-linux-gnu/12.0.0/../../../../include/c++/12.0.0/concepts:67:28: note: because '__is_base_of(std::ranges::views::__adaptor::_RangeAdaptorClosure, std::basic_string<char>)' evaluated to false
    concept derived_from = __is_base_of(_Base, _Derived)
                           ^
7 errors generated.
Compiler returned: 1

The text was updated successfully, but these errors were encountered:

db-src · 2021-12-14T20:53:27Z

ldionne · 2021-12-14T23:31:40Z

Clang on Godbolt uses libstdc++ by default, not libc++. You need to pass -stdlib=libc++ in order to use libc++: https://godbolt.org/z/f3cdjT61x.

If you do that, you will see that libc++ does not implement all of ranges yet, but we're working on it. In fact, we don't even enable Ranges in the version of LLVM we ship (e.g. 12.0) because we wanted to have a coherent whole before shipping anything.

TLDR: You should report this bug to libstdc++ instead, and you should drop your whiny tone that makes it sound as-if the people who contribute to these OPEN SOURCE projects owe you something, cause that's not helping your case.

db-src · 2021-12-15T08:04:48Z

Thanks for the explanation, and I apologise for my previous tone.

jwakely · 2022-01-11T21:21:20Z

TLDR: You should report this bug to libstdc++ instead

Please don't, we have more than one report for this already, and it's a Clang bug: #44178

llvmbot · 2022-01-16T16:48:33Z

@llvm/issue-subscribers-clang-frontend

bachittle · 2022-09-23T18:48:05Z

this is fixed as of the latest commit

…lvm/llvm-project#52696

wip.. We seem to hit llvm/llvm-project#52696 See: https://godbolt.org/z/7abh7rzaP ``` /usr/bin/../lib/gcc/x86_64-linux-gnu/11/../../../../include/c++/11/bits/iterator_concepts.h:979:13: error: no matching function for call to '__begin' = decltype(ranges::__cust_access::__begin(std::declval<_Tp&>())); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ``` Signed-off-by: Matan Breizman <mbreizma@redhat.com>

Currently our jammy ci (jenkins) builders are only able to (apt) install clang 14 as the latest version available. Clang stable is already at 19 today (i.e we're 5 major releases behind). Meaning, full support of C++20 and some bugs [1] requiring us to update the compiler used for make check. As updating to Ubuntu 24 is not feasable in the near future and containerized builds is not yet merged - with this patch, we would get clang-16 directly form llvm installation script. Note: discover_compiler() would prefer clang-16 even if clang-14 will be installed by apt in INSTALL_EXTRA_PACKAGES defined below. [1] llvm/llvm-project#52696 Signed-off-by: Matan Breizman <mbreizma@redhat.com>

github-actions bot added the new issue label Dec 14, 2021

mkurdej added libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. libc++abi libc++abi C++ Runtime Library. Not libc++. and removed libc++abi libc++abi C++ Runtime Library. Not libc++. labels Dec 14, 2021

ldionne closed this as completed Dec 14, 2021

mkurdej removed the new issue label Dec 28, 2021

Quuxplusone added clang:frontend Language frontend issues, e.g. anything involving "Sema" concepts C++20 concepts and removed libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. labels Jan 16, 2022

Quuxplusone added the duplicate Resolved as duplicate label Jan 27, 2022

EugeneZelenko closed this as not planned Won't fix, can't repro, duplicate, stale Sep 23, 2022

chriselrod added a commit to LoopModels/LoopModels that referenced this issue Sep 24, 2022

AbstractRange because std::ranges::range seems broken on latest Clang l…

6b213d6

…lvm/llvm-project#52696

SainoNamkho mentioned this issue Oct 3, 2022

What's the appropriate approach to #1157? isocpp/CppCoreGuidelines#1978

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Arisa-Snowbell mentioned this issue Mar 17, 2023

Clang can't compile newest version hyprwm/Hyprland#1808

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fix build for clang ZhengPeiRu21/mod-playerbots#170

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usx95 added this to C++ 20 in Clang Jul 12, 2023

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Swift: skip declarations marked as unavailable github/codeql#14437

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Modernize evolution_replacement test morinim/ultra#3

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anarthal mentioned this issue Feb 28, 2024

Build failure with clang-14 when using libstdc++ boostorg/parser#131

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[onedpl][ranges][productization] Range API productization, MVP plan, Part 2 uxlfoundation/oneDPL#1471

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script/run-make: clang 14->19 ceph/ceph#61740

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Use views. aibasel/downward#252

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C++20 ranges/views are broken, via std::ranges::ref_view - iterator_concepts.h:980:13: error: no matching function for call to '__begin' #52696

C++20 ranges/views are broken, via std::ranges::ref_view - iterator_concepts.h:980:13: error: no matching function for call to '__begin' #52696

db-src commented Dec 14, 2021 •

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ldionne commented Dec 14, 2021

db-src commented Dec 15, 2021

jwakely commented Jan 11, 2022

llvmbot commented Jan 16, 2022

bachittle commented Sep 23, 2022

C++20 ranges/views are broken, via std::ranges::ref_view - iterator_concepts.h:980:13: error: no matching function for call to '__begin' #52696

C++20 ranges/views are broken, via std::ranges::ref_view - iterator_concepts.h:980:13: error: no matching function for call to '__begin' #52696

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