[racket-dev] possible 5.2.900.1 bug involving rest argument

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Sun Jul 29 10:15:25 EDT 2012

On Jul 28, 2012, at 8:25 PM, Eli Barzilay wrote:

>  andmap: contract violation
>    expected: list?
>    given: '(#<syntax:/tmp/zzz:5:19 Y> . #<syntax:/tmp/zzz:5:23 Z>)
>    argument position: 2nd
>    other arguments...:
>     #<procedure:void>
>    context...:
>     /home/scheme/html/release/racket/collects/syntax/parse/private/residual.rkt:206:0: predicate-ellipsis-parser
>     /tmp/zzz: [running body]
> and the trace that points at synax/parse/private/residual.rkt was
> there when I tried your original line, so I think that it's the right
> error.
> (I'll let Ryan take it from here, I just did a semi-blind tracking...)

Eli, note how contract messages helped shift blame from compiler to syntax/parse. 

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