[racket-dev] strange top-level binding for module-defined identifiers

I'll push a repair.

The problem is in the representation of syntax objects and the flaky
way that it was generalized to support identifiers that move across
submodule boundaries (but the problem didn't just affect programs with
submodules, in this case).

At Thu, 24 Jul 2014 16:24:42 -0400, Sam Tobin-Hochstadt wrote:
> Ok, here's a much simpler example:
> 
> #lang racket
> 
> (module foo racket
>   (provide def-wrap)
>   (define-syntax-rule (def-wrap)
>     (begin  (define y 1) y)))
> 
> (module bar racket
>   (require (submod ".." foo))
>   (def-wrap))
> 
> In the fully-expanded syntax, the macro stepper suggests that `y` has
> no apparent binding.
> 
> At this point it seems unlikely that it's a bug, since it happens all
> the time, but I still don't understand.
> 
> Sam
> 
> On Thu, Jul 24, 2014 at 4:08 PM, Sam Tobin-Hochstadt
> <samth at cs.indiana.edu> wrote:
> > If you take this program (which is a lot like the implementation of
> > `racket/fixnum`):
> >
> > #lang racket/base
> >
> > (require '#%flfxnum
> >          racket/private/vector-wraps
> >          racket/unsafe/ops
> >          (for-syntax racket/base))
> >
> > (define-vector-wraps "fxvector"
> >   "fixnum?" fixnum?
> >   fxvector? fxvector-length fxvector-ref fxvector-set! make-fxvector
> >   unsafe-fxvector-ref unsafe-fxvector-set! unsafe-fxvector-length
> >   in-fxvector*
> >   in-fxvector
> >   for/fxvector
> >   for*/fxvector
> >   fxvector-copy
> >   0)
> >
> > And run it in the macro stepper with macro hiding off, at the end you
> > get a fully-expanded module where the first definition is
> > `:fXvector-gen`. However, if you click on this identifier, either in
> > the definition or in a subsequent use, it says "Apparent identifier
> > binding: none" (which means that `identifier-binding` returns #f,
> > which can be confirmed on the expanded syntax).
> >
> > How can this happen? Is it a bug in something, or a special case that
> > I didn't expect?
> >
> > Sam