On Tue, Aug 17, 2010 at 9:21 PM, Shriram Krishnamurthi <s...@cs.brown.edu>
wrote:
> we couldn't type the generator code (a bad interaction between mutation
> and occurrence typing).
In almost all cases, when TR rejects your program because of this,
your code is incorrect in the presence of threads and/or futures (and
sometimes continuations) as well. For example, this program:
#lang typed/racket
(: x Any)
(define x #f)
(: f (Any -> Void))
(define (f v) (set! x v))
(if (number? x)
;; no call to `f' here
(add1 x)
0)
won't typecheck, but you might think it should. However, the call to
`f' can be in another thread/future, which can happen between the test
and the `add1', breaking your program.
--
sam th
sa...@ccs.neu.edu
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