Hey Zelphir ! I think it is related to something I noticed few monthes ago : https://lists.gnu.org/archive/html/guile-user/2021-02/msg00061.html
I cross posted the message over here : https://srfi-email.schemers.org/srfi-64/msg/16101182/ I got no responses from SRFI-64 mailing list. I think, when an expression throws an exception, it also returns #f. Unfortunately, you expect #f as well in your test. Jérémy
