Trouble using (current-filename)

[Mark H Weaver <mhw@netris.org>]

I put the following test module in my load path:

  (define-module (current-filename-fail)
    :export (my-filename))
  (define my-filename (current-filename))
  (define (force-a-warning-message) (identity 1 2 3))

And this is what I see with Guile 2.0.5:

  GNU Guile 2.0.5
  Copyright (C) 1995-2012 Free Software Foundation, Inc.
  
  Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
  This program is free software, and you are welcome to redistribute it
  under certain conditions; type `,show c' for details.
  
  Enter `,help' for help.
  scheme@(guile-user)> ,use (current-filename-fail)
  ;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
  ;;;       or pass the --no-auto-compile argument to disable.
  ;;; compiling /home/mhw/guile-modules/current-filename-fail.scm
  ;;; current-filename-fail.scm:4:34: warning: possibly wrong number of arguments to `identity'
  ;;; compiled /home/mhw/.cache/guile/ccache/2.0-LE-4-2.0/home/mhw/guile-modules/current-filename-fail.scm.go
  scheme@(guile-user)> my-filename
  $1 = #f

The (force-a-warning-message) line shows that source information is
available.  The same thing happens if I remove that line, or if I try
with stable-2.0.

What am I doing wrong?

    Thanks,
      Mark