I think something like this actually happened with one of the first scheme implementations, but that was because they wrote the GC in scheme so they had to do i

I think something like this actually happened with one of the first scheme implementations, but that was because they wrote the GC in scheme so they had to do it that way for a very small subset of the system (is the GC code). But yeah other than that I can't think of any examples (and my example is kind of the exception that proves the rule).