while (peekingItr.hasNext()) {
        Range<C> range = peekingItr.next();
        while (peekingItr.hasNext()) {
          Range<C> nextRange = peekingItr.peek();
          if (range.isConnected(nextRange)) {
            checkArgument(
                range.intersection(nextRange).isEmpty(),
                "Overlapping ranges not permitted but found %s overlapping %s",

        }

        private <P> ActivationFrame nextFrame(String property, Function<P, InputLocationTracker> child) {
            @SuppressWarnings("unchecked")
            final Optional<P> parent = (Optional<P>) stk.peek().parent;
            return new ActivationFrame(property, parent.map(child));
        }

        @Override
        public Activation transformActivation(Activation target) {