[racket-dev] raco setup hangs

`raco setup' hangs when it tries to build my planet package. I narrowed
down the problem to this file

#lang racket/base

(require racket/class)

(define bar
  (mixin () ()
    (define (foo)
      (let loop ([x 0])
        (printf "loop!\n")
        (loop (begin
                ;; uncomment for this to fail #;
                (send this anything)
                2))))))

Put that in bar.rkt or whatever and add it as the main file of info.ss.
If the line (send this anything) is uncommented then `raco setup' will
hang. It dosen't print "loop!" or anything so its not obvious whats
wrong. `raco make bar.rkt' works though.

I'm not exactly sure when this behavior started occurring but it was
something like 3 weeks ago.