Currently the semantics of calling set! or define
on an imported binding is undefined. Do we
want to specifically make this an error?
I think we want importing bindings to be immutable in a module and mutable at the REPL.
R6RS, Chez's Modules, and Racket's module forms all, to my knowledge enforce immutability constraints on imported identifiers. I am inclined to think that this is something we want to maintain. I think immutable imports makes more sense both from efficiency and code reasoning perspectives. Otherwise, I think we could have a lot of confusion concerning bindings and evaluation orders when invoking libraries.
We voted this is an error.