Scala sort of has this with the @tailrec annotation. The compiler will always attempt TCO, but the annotation makes failure to do so a compilation error. (Its n

Scala sort of has this with the @tailrec annotation. The compiler will always attempt TCO, but the annotation makes failure to do so a compilation error. (Its not a perfect situation though, since there can still be functions assumed to be tail recursive without @tailrec, and whose behavior can change without warning)