Выброс исключения из noexcept функции

#include <stdexcept>

enum class result_t {
    successful,
    failed
};

result_t external_proc();

void call_external_proc() noexcept {
    const auto result = external_proc();
    if( result_t::failed == result )
        throw std::runtime_error( "external proc failed" );
}