Thanks for your clearly-written example. I'll confirm when I have more bounded-space tests passing with the proposed fix.
It is confirmed. O(N) space on (x+ (srfi-155-integers) N), as well as other tests, and parameter behavior checks out within the loop (parameters have their correct values).
Congratulations and thank-you Marc! The overall design across the three SRFIs is sound even if not a trivial porting effort.
-jim