I can think of counter-examples, but none especially compelling, and amconvinced by Al's example that bound=? makes more sense. I've pushedthe change to master.A counter-example would be my current implementation of SRFI 147/148, which relied on the free-identifier=? comparison. But it is also not that compelling because it is possible to rewrite it, which I am currently doing.As for the change to Chibi, you also have to apply the change here:(I forgot to mention that line in my earlier post as well.)Marc--Alex