#lang plait
(define-type BT
[mt]
[node (v : Number) (l : BT) (r : BT)])
(define (size-wrong (t : BT))
(+ 1 (+ (size-wrong (node-l t))
(size-wrong (node-r t)))))
(size-wrong (mt))
#lang plait
(define-type BT
[mt]
[node (v : Number) (l : BT) (r : BT)])
(define (size-wrong (t : BT))
(+ 1 (+ (size-wrong (node-l t))
(size-wrong (node-r t)))))
(size-wrong (mt))