> I've noticed that Typed Racket adds seemingly unnecessary chaperones when > the Any type is involved, but maybe they are necessary for some reason? The > following code tries to create a chaperone that I don't think is necessary. > > #lang racket > > (module m typed/racket > (provide f) > (: f (-> Any Any)) > (define (f x) x)) > (require 'm) > > (struct s (a b) #:transparent #:authentic) > (f (s 1 2)) > > Is there a reason for the chaperone? Should I report this and similar > situations as Github issues?
Typed Racket uses Any chaperones to protect its values from untyped code. For example, if typed code sent a vector to untyped, then the Any chaperone would prevent `vector-set!`s I agree the chaperone isn't necessary in your example because `f` never receives a typed value. I also can't think of a way to use an un-chaperoned version of `f` to break type soundness ... so maybe there is a general principle here, about how a typed function creates an Any result, that TR could learn. If you have ideas and/or more examples, then yes please open an issue. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAFUu9R772b608dSGMgatukR%2BtaaSZokDaTKxek_n%3D4bhfczrgg%40mail.gmail.com.
