[plt-scheme] top-level bindings vs. module imports

This seems odd to me:

> (define (car) (car))
> (car)
car: expects 1 argument, given 0

I would expect it to loop.  I think I know what's going on: the
identifier `car' is module-imported, so it gets expanded to itself
instead of to `(#%top . car)' in the new procedure body.  Is this a
bug?

--dougo at place.org