(define (do-test)
    
      (define env '(1))
      ;(define env (list 1))
    
      (display env)
      (if (not (equal? (car env) 1))
        (error "assertion failed.")
        'ok)
    
      (set-car! env 2)
      'ok)
    
    (do-test)
    (do-test)

assertion failed.

 === context ===
Line 1:0: do-test

(1)(2)