This was mind-boggling to debug!

In syntax-rules, the pattern (x ...) will match #nil, since it
matches the empty list.  This can have surprising consequences.

Consider:

  (define-syntax test
    (syntax-rules ()
      ((test (x ...))
       (x ...))
      ((test x)
       x)))

  (test (+ 1 2))  ; => 3
  (test 123)      ; => 123
  (test #f)       ; => #f
  ;; However...
  (test #nil)     ; error


Anyway, attached is a patch to fix the issue in match.


- Taylan