[racket] Typed Racket and require/typed for polymorphic structs

On 2013-08-07 08:55:17 -0700, Eric Dobson wrote:
> That doesn't solve the issue. The issue is not in struct/c and thus
> using struct/dc has the same problem. A immutable field cannot have a
> impersonator contract applied to it because that would be equivalent
> to mutating the field.

You're right, and the immutability restriction is enforced at the level
of impersonators/chaperones, so it doesn't look like there's an easy
way around this. Hmm.

Cheers,
Asumu