[racket-dev] [plt] Push #27395: master branch updated

Isn't the assymetric check the wrong way? If it returns true, we know
nothing because it might not be a hash-set, but if it returns false
then we know that it is not a hash set?

On Fri, Aug 30, 2013 at 3:30 PM, Asumu Takikawa <asumu at ccs.neu.edu> wrote:
> On 2013-08-30 16:15:23 -0400, Sam Tobin-Hochstadt wrote:
>> I worry about mutable sets here, but I can't think of any bugs it can
>> cause ATM.
>
> I don't have any segfault-causing bugs, but here's a violation of the blame
> theorem:
>
>   #lang racket
>
>   (module a0 racket
>     (define s (mutable-set 1 2 3))
>     (provide s))
>
>   (module a typed/racket
>     (require/typed (submod ".." a0) [s Any])
>     (: x (Setof Any))
>     (define x (assert s generic-set?))
>     (provide x))
>
>   (require 'a)
>   x
>
> Cheers,
> Asumu
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