"cannot coerce inexact literal to fixnum"

[Al]

(import (chicken fixnum))
; (declare (fixnum))
(define mp most-positive-fixnum)

(display mp) (newline)
(display (string->number (number->string mp))) (newline)

(display #x7fffffff) (newline)
(display (string->number "#x7fffffff")) (newline)


Obviously the first number is much greater than INT32_MAX. However, if I 
enable fixnum, csc chokes on both the third and fourth display's with: 
"Error: cannot coerce inexact literal `2147483647' to fixnum". It 
compiles and runs fine if those lines are commented out (or if fixnum is 
disabled).


Not sure what's wrong here. Tried with both 5.3.0 and 5.3.1-pre.


-- Al