(defun nreconc (x y)
#!+sb-doc
"Return (NCONC (NREVERSE X) Y)."
- (do ((1st (cdr x) (if (atom 1st) 1st (cdr 1st)))
+ (do ((1st (cdr x) (if (endp 1st) 1st (cdr 1st)))
(2nd x 1st) ;2nd follows first down the list.
(3rd y 2nd)) ;3rd follows 2nd down the list.
((atom 2nd) 3rd)