[racket] Bug in TR for/sum: ??

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Thu Mar 28 16:52:56 EDT 2013

Perhaps for/sum should adapt its base case answer to the return type? 



On Mar 28, 2013, at 4:03 PM, Sam Tobin-Hochstadt <samth at ccs.neu.edu> wrote:

> I'm not sure what you're referring to. This program doesn't typecheck,
> because if both vectors were empty, the result is exact 0, which isn't
> a `Float`.
> 
> Sam
> 
> On Thu, Mar 28, 2013 at 3:56 PM, Ray Racine <ray.racine at gmail.com> wrote:
>> Is this a bug?
>> 
>> #lang typed/racket/base
>> 
>> (define: βns : (Vectorof Float) '#(1.0 2.0 3.0))
>> (define: χns : (Vectorof Float) '#(4.0 5.0 6.0))
>> 
>> (for/sum: : Float
>>  ([βn : Float (in-vector βns)]
>>   [χn : Float (in-vector χns)])
>>  (* βn χn))
>> 
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