aren't hygienic macros supposed to be hygienic?

[Marco Maggi]

Ciao,

  I make the module:

;; syntaxes.scm --

(define-module (syntaxes)
  #:use-syntax (ice-9 syncase)
  #:export (when))

(define-syntax when
  (syntax-rules ()
    ((_ e0 e1 ...)
     (if e0 (begin e1 ...)))))

;;; end of file

and then the file:

;; syntax-test.scm --

(define-module (this)
  #:use-module (syntaxes))

(let ((if       (lambda (. args)
                  (scm-error 'wrong 'there "bad binding" #f #f))))
  (when #t
    (display 'true)(newline)))

;;; end of file

evaluating I get this output:

true
Backtrace:
In unknown file:
   ?: 0* (let* ((if (lambda args #))) (if #t (begin (display
#) (newline))))
   ?: 1  (when #t (display (quote true)) (newline))
   ...
   ?: 2  [scm-error wrong there "bad binding" #f #f]

<unnamed port>: In procedure there in expression (scm-error
(quote wrong) (quote there) ...):
<unnamed port>: bad binding

why?

--
Marco Maggi

"They say jump!, you say how high?"
Rage Against the Machine - "Bullet in the Head"