[racket] require/typed predicates

On Wed, May 4, 2011 at 9:14 PM, David Van Horn <dvanhorn at ccs.neu.edu> wrote:
> I used to be able to write things like this in TR:
>
> #lang typed/racket
> (require/typed lang/htdp-advanced
>  [char? (Any -> Boolean : Char)])
>
> But now I get:
>
> Type Checker: Type (Any -> Boolean : Char) could not be converted to a
> contract. in: (Any -> Boolean : Char)
>
> Is there a way to recover what I was doing?
>
> Thanks,
> David

I think this was a soundness bug that has been fixed.  How could Typed
Racket guarantee this in a useful way?

--Carl