Break with label

I cannot find in the book ho to break out of a nested loop using a label.

for x in container_of_containers {
  for y in x {
    if test_y(y) {
      break outer;

Is there some rusty way? I feel I am missing something simple about the syntax

Yes, you can do this -- it just looks like a lifetime: 'outer: ... break 'outer; ...

It's at least in the reference here: