Compilation error in stream-filter/print_primes sample

[Insomniac-Ossifrage]

Compiling the 'print_primes' sample using Clang 10.0.0 produces the following error:

/home/yago/.local/share/JetBrains/Toolbox/apps/CLion/ch-0/211.6693.114/bin/cmake/linux/bin/cmake --build /home/yago/Desktop/grppi/cmake-build-d-clang --target print_primes -- -j 25
[ 50%] Building CXX object samples/stream-filter/print_primes/CMakeFiles/print_primes.dir/main.cpp.o
In file included from /home/yago/Desktop/grppi/samples/stream-filter/print_primes/main.cpp:28:
In file included from /home/yago/Desktop/grppi/include/grppi/grppi.h:20:
In file included from /home/yago/Desktop/grppi/include/grppi/dyn/dynamic_execution.h:19:
In file included from /home/yago/Desktop/grppi/include/grppi/dyn/../seq/sequential_execution.h:23:
In file included from /home/yago/Desktop/grppi/include/grppi/common/patterns.h:24:
In file included from /home/yago/Desktop/grppi/include/grppi/dyn/../seq/../common/filter_pattern.h:20:
/home/yago/Desktop/grppi/include/grppi/dyn/../seq/../common/meta.h:135:31: error: no matching function for call to 'input_type_l'
  using input_type = decltype(input_type_l(std::declval<F>()));
                              ^~~~~~~~~~~~
/home/yago/Desktop/grppi/include/grppi/dyn/../seq/../common/filter_pattern.h:34:28: note: in instantiation of template type alias 'input_type' requested here
  using input_type = meta::input_type<Predicate>;
                           ^
/home/yago/Desktop/grppi/include/grppi/stream_filter.h:44:12: note: in instantiation of template class 'grppi::filter_t<bool (&)(int)>' requested here
    return filter_t<Predicate>{std::forward<Predicate>(predicate_op), true};
           ^
/home/yago/Desktop/grppi/samples/stream-filter/print_primes/main.cpp:50:12: note: in instantiation of function template specialization 'grppi::keep<bool (&)(int)>' requested here
    grppi::keep(is_prime),
           ^
/home/yago/Desktop/grppi/include/grppi/dyn/../seq/../common/meta.h:132:42: note: candidate template ignored: substitution failure [with F = bool (*)(int)]: type 'bool (*)(int)' cannot be used prior to '::' because it has no members
  decltype(input_type_t(&F::operator())) input_type_l(F);
                         ~               ^
1 error generated.
make[3]: *** [samples/stream-filter/print_primes/CMakeFiles/print_primes.dir/build.make:82: samples/stream-filter/print_primes/CMakeFiles/print_primes.dir/main.cpp.o] Error 1
make[2]: *** [CMakeFiles/Makefile2:1241: samples/stream-filter/print_primes/CMakeFiles/print_primes.dir/all] Error 2
make[1]: *** [CMakeFiles/Makefile2:1248: samples/stream-filter/print_primes/CMakeFiles/print_primes.dir/rule] Error 2
make: *** [Makefile:376: print_primes] Error 2