Panics are possible with #![no_std], but it does require that you supply a working implementation of panic_fmt, which I haven't gotten to yet (mostly because I was waiting on panic-as-abort to land which it recently did).

OK, another option is to make it an explicit infinite "loop{...}" which only exits by returning. The "0.." is effectively infinite anyway, because it will overflow freely in release mode. (But surely you'll hit an invalid memory page before that happens.)

You're right, I think this version is a bit clearer:

https://is.gd/lck8c7

NB: you still need panic_fmt with panic == abort; the default panic handler still prints a message, even though it doesn't go through with the unwinding.

panic_fmt can be as simple as (C pseudocode):

    printf("...");
    kill(getpid(), SIGABRT);
    while(true)
      /* In case kill(ABRT) returns, halt. */;