let-match and don't-care elements in 0.6.3

[stktrc <stktrc@yahoo.com>]

The manual says about let-match:

"Mvars is a list of vars that is bound to the match and submatches of
the string; #F is allowed as a don't-care element."

With 0.6.3 I try

(let-match (regexp-search (rx (submatch "aa") (submatch "bb")) "aabb")
           (#f aa bb)
           (format #t "aa: ~a bb: ~a~%" aa bb))

and get

Warning: use of macro doesn't match definition
         (let ((#f (match:substring ?match-var 0))) (let-match-aux ?match-var 
(+ 1 0) (aa bb) (format #t "aa: ~a bb: ~a~%" aa bb)))
'syntax-error

This seemed to work in 0.6.2.