(declare
 (unit foo-v)
 (strict-types)
 (block))

(module
 foo-v
 ()

 (import scheme chicken)
 (import (prefix foo b:))

 (: foo (fixnum --> fixnum))
 (define (foo x) (* x 7))

 ;; HERE I tried to simply use
 ;;
 ;; (set! b:foo foo)
 (b:s-foo! foo)

)