ZYAN_UNREACHABLE
# define ZYAN_UNREACHABLE for(;;)
# define ZYAN_UNREACHABLE __builtin_unreachable()
# define ZYAN_UNREACHABLE __assume(0)
# define ZYAN_UNREACHABLE for(;;)
# define ZYAN_UNREACHABLE for(;;)
# define ZYAN_UNREACHABLE { __fastfail(0); for(;;){} }
# define ZYAN_UNREACHABLE { assert(0); abort(); }