Compilation error: std::execution example

satacker@ubuntu:~/wg21_p2300_std_execution/build$ clang++-12 -std=c++2b ../examples/schedulers/is.cpp -I../include/  -fcoroutines-ts -lpthread -stdlib=libc++
In file included from ../examples/schedulers/is.cpp:1:
In file included from ../examples/schedulers/inline_scheduler.hpp:18:
../include/execution.hpp:631:18: error: value of type 'tag_invoke_result_t<std::execution::__scheduler_queries::__impl::get_forward_progress_guarantee_t, const example::inline_scheduler &>' (aka 'std::execution::forward_progress_guarantee') is not contextually convertible to 'bool'
          return tag_invoke(get_forward_progress_guarantee_t{}, std::as_const(__t)) ? true : false;
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../examples/schedulers/is.cpp:8:58: note: in instantiation of function template specialization 'std::execution::__scheduler_queries::__impl::get_forward_progress_guarantee_t::operator()<example::inline_scheduler &>' requested here
  auto k = std::execution::get_forward_progress_guarantee(s);
                                                         ^
1 error generated.