Changes to Typeable

[Simon Peyton-Jones]

| Does this imply forbidding user-written instances of Typeable? If yes,
| then I guess some currently accepted programs would also be rejected
| (those with manual instances)?

Yes, that's the idea; I should have said that.  Allowing users to write instances leads to potential un-soundness when doing dynamic type casts, so it has always been a Bad Idea.

Simon