Re: set-car! and set-cdr! throw vm-exception on lists defined with quotation

   Date: Sun,  4 Apr 2010 21:15:31 +0000 (UTC)
   From: Andrew Stok <[email protected]>

   This result was unexpected.  The only difference between the two lists
   is the method in which they were defined.  set-cdr! exhibits the same
   behavior.

The values of literal expressions such as quotations are immutable.
See the R5RS, Section 3.4 `Storage Model'.  Many Scheme systems do not
enforce this, but exhibit behaviour such as

(let ((f (lambda () '(5))))
  (set-car! (f) 3)
  (car (f)))
;Value: 3

Scheme48, however, enforces this.