[racket-dev] Release Announcement for v6.1.1, Second Draft

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Wed Oct 29 21:46:50 EDT 2014

I don't think that "it's true of every type system everywhere" is a
good rationale for not owning backwards-incompatible changes (even
when they are "good" backwards incompatible changes, as this one
certainly is). I do agree with you, however, that what is especially
bad is requiring changes to "working" code bases (for whatever
definition of that word you wish to take (that is most friendly to
people that use Racket)).

How about this one? (Starting from Matthias's offering and editing the
apology from Sam's a bit.)

Typed Racket closes a safety hole in the typing for the
  exception system. The revised type system restricts raise so
  that only instances of the exn structure type and flat data
  are communicated to handlers. As a side-effect, previously
  well-typed programs may fail to typecheck.

Robby

On Wed, Oct 29, 2014 at 5:12 PM, Sam Tobin-Hochstadt
<samth at cs.indiana.edu> wrote:
> The reason I don't like the second sentence you wrote is that it's
> true of every type system everywhere. And also, the more significant
> change for users will almost certainly be the first one (it's required
> changes to several packages already) -- almost no one raises anything
> that isn't an exn, and so I haven't seen any code actually affected by
> the second change.

Posted on the dev mailing list.