Welcome to the CHICKEN Scheme pasting service

(define-syntax foo
  (ir-macro-transformer
   (lambda (e i c)
     (print "expanding" e)
     `(begin))))

(foo ()) <- OK

(module bar *
 (import chicken scheme)

 (foo ()) <- not OK
)

Output:
expanding(foo25 ())

Error: illegal non-atomic object: ()
inside expression `(foo ...)