... Or just add quotes (yes, please) and keep the colon:
"foo": for 1... { next "foo"; }
Given that "next" throws a control-exception that is handled by the looping construct, perhaps we sohuld think of the label as an optional parameter to the looping statement function
for :label<foo> 1... { next "foo" };
This makes labels somewhat less general, but maybe C<goto> should be handled separately, anyway. For example, maybe you can only use C<goto> if you've asked to "use continuations;".