[racket] typed racket: inconsistent interaction between typed and untyped code?

On Fri, Mar 4, 2011 at 6:14 PM, Carl Eastlund <cce at ccs.neu.edu> wrote:
> Ah.  This looks like the bug I've seen reported elsewhere that causes
> blame to be associated with the wrong module.  The actual problem
> going on here appears to be that test-sim passes an "Any" to
> toplevel-vals, but sim-structs expects toplevel-vals to receive a
> toplevel.  The blamed module, sim, isn't involved at all.

Yes, this appears to be the same as the recently discussed bug in the
`via' infrastructure, and not a problem in TR.

> Carl Eastlund
>
> On Fri, Mar 4, 2011 at 6:06 PM, Matthias Felleisen <matthias at ccs.neu.edu> wrote:
>>
>> The interesting thing is that the contract blames the TYPED module,
>> contrary to all the blame theorems. Time to fix them. Anyone?
>>
>> On Mar 4, 2011, at 5:22 PM, Carl Eastlund wrote:
>>
>>> Danny,
>>>
>>> This is an issue with the type Any.  Typed Racket has to protect all
>>> values passed from typed code to untyped code from all possible
>>> type-unsound uses.  For many kinds of values, this means Typed Racket
>>> has to close off pretty much all kinds of uses.  In your case, you
>>> have a transparent struct.  If it were unwrapped, untyped code could
>>> inspect it, extract a constructor for its struct type, create an
>>> instance with field contents that violate your define-struct:
>>> declaration, and pass it back into typed code.  You have to be very
>>> careful with Any on boundaries, because it has to make a lot of things
>>> completely opaque.
>>>
>>> Sadly, off the top of my head, I don't have a quick workaround for
>>> you.  Maybe Sam will have a better suggestion.
>>>
>>> Carl Eastlund
>>>
>>> On Fri, Mar 4, 2011 at 4:20 PM, Danny Yoo <dyoo at cs.wpi.edu> wrote:
>>>> I'm hitting an error when trying to pass values between typed and
>>>> untyped code.  I've shrunk the error to the following test code.
>>>> Consider three files 'sim-structs', 'sim.rkt', and 'test-sim.rkt'.
>>>> sim-structs and sim are written in Typed Racket, and test-sim is
>>>> written in regular racket.
>>>>
>>>> ;; sim-structs.rkt
>>>> #lang typed/racket/base
>>>> (provide (all-defined-out))
>>>> (define-struct: machine ([env : (Listof Any)]))  #:transparent)
>>>> (define-struct: toplevel ([vals : (Vectorof Any)])  #:transparent)
>>>>
>>>>
>>>> ;; sim.rkt
>>>> #lang typed/racket/base
>>>> (require "sim-structs.rkt")
>>>> (provide new-machine)
>>>> (: new-machine ( -> machine))
>>>> (define (new-machine)
>>>>  (make-machine (list (make-toplevel (vector 'foobar)))))
>>>>
>>>>
>>>> ;; test-sim.rkt
>>>> #lang racket
>>>> (require "sim.rkt" "sim-structs.rkt")
>>>> (toplevel-vals (first (machine-env (new-machine))))
>>>>
>>>>
>>>>
>>>> When I try to execute test-sim, it fails with the following error:
>>>>
>>>>
>>>> tesla ~/work/js-sicp-5-5 $ /pro/plt/software/racket/5.1/std/bin/racket
>>>> test-sim.rkt
>>>> contract violation: expected <toplevel?>, given: #<Typed Value:
>>>> #(struct:toplevel #(foobar))>
>>>>  contract on toplevel-vals24 from
>>>>    (file
>>>>     /home/dyoo/work/js-sicp-5-5/sim-structs.rkt)
>>>>  via
>>>>    (file
>>>>     /home/dyoo/work/js-sicp-5-5/test-sim.rkt)
>>>>  blaming
>>>>    (file /home/dyoo/work/js-sicp-5-5/sim.rkt)
>>>>  contract: (-> toplevel? (vectorof Any))
>>>>        at: /home/dyoo/work/js-sicp-5-5/sim-structs.rkt:11.16
>>>>
>>>>  === context ===
>>>> /pro/plt/software/racket/5.1/std/collects/racket/contract/private/blame.rkt:58:0:
>>>> raise-blame-error
>>>> /home/dyoo/work/js-sicp-5-5/test-sim.rkt: [running body]
>>>>
>>>>
>>>>
>>>> It looks as though there's some special "Typed Value" wrapper there
>>>> that shouldn't be visible from the untyped test-sim code.  Is there a
>>>> workaround?
>
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-- 
sam th
samth at ccs.neu.edu