Warning elimination

[Adam Warner <lists at consulting dot net dot nz>]

Dear Per Bothner and list members,

I'm new to Kawa but am already impressed with its implementation and
superb integration with the Java Virtual Machine.

I'm wondering if there is a way to eliminate the "no definitely
applicable method `<init>' in java.io.File" when loading this seemingly
innocuous function from the REPL:

(define (file-date file)
  (java.io.File:lastModified
    (if (string? file) (make 'java.io.File file) file)))

It appears I need to declare the input type of argument `file' as
<string> or <java.io.File>, and I don't believe that declaring types as
sets are supported in Kawa.

The version below contains enough information for a compiler to deduce
that `object' only evaluates to a <java.io.File> type (this would be
easier for the compiler to deduce if a `type?' function was standard):

(define (file-date file)
  (let ((object (cond ((string? file)
                       (make 'java.io.File file))
                      ((eq? (java.lang.Class:getName
                             (java.lang.Object:getClass file))
                            'java.io.File)
                       file)
                      (else (error "file-date; illegal type:" file)))))
    (java.io.File:lastModified object)))

Obviously this warning isn't a showstopper. I'd just like to know how to
suppress it in the event it's a spurious warning or how to write this
function correctly to eliminate the warning.

Regards,
Adam Warner