[racket] for/and unhappiness with 'not' and the definition of Booleans?

From: Sam Tobin-Hochstadt (samth at ccs.neu.edu)
Date: Fri Aug 26 08:06:43 EDT 2011

This is now fixed in git.

On Sat, Aug 20, 2011 at 2:00 PM, John Clements
<clements at brinckerhoff.org> wrote:
> I'm unable to get for/and to typecheck when the body is an application of 'not'. I've tried many variations on the following, without success:
>
> #lang typed/racket
>
> (for/and: : Any ([i (in-range 4)])
>  (not (my-pred)))
>
> (define (my-pred)
>  #f)
>
> =>
>
> Type Checker: Expected True, but got Boolean in: (for/and: : Any ((i (in-range 4))) (not (my-pred)))
>
>
> The error message suggests that the body must have type "True", though I suspect this is a consequence of if-splitting somehow.
>
> Any suggestions or improvements to error messages appreciated.
>
> John
>
>
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-- 
sam th
samth at ccs.neu.edu



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