I come from scheme land, where that internal tail recursive function is the way to go for speed (internal definitions are easy to verify that they are never cha

I come from scheme land, where that internal tail recursive function is the way to go for speed (internal definitions are easy to verify that they are never changed, which allows to skip a lookup - the same should be true for CL). I thought the same would be true for SBCL, but apparently it needed some nudging.