[racket] #<undefined> and backward compatibility

On 04/18/2014 07:54 AM, Matthew Flatt wrote:
>
> No one expects the #<undefined> value!

Is this a... subtle... reference? [1]

> Based on our experiment so far, it looks like the drawbacks probably
> outweigh the benefits...

I think you meant this the other way around. :)

Another benefit is that Typed Racket will no longer have to consider 
non-function letrec bindings as having the type (U Undefined A) where A 
is the "real" type. (Technically, (U Undefined A) *was* the real type.)

Neil ⊥

[1] No one expects the Spanish Inquisition!
     https://www.youtube.com/watch?v=7WJXHY2OXGE