[racket-dev] parse errors in types, poly-dots cause me headaches

From: Sam Tobin-Hochstadt (samth at cs.indiana.edu)
Date: Tue Nov 18 11:58:42 EST 2014

No, I ran it, it barfed, and then I figured out what went wrong. Then
I sent you an email with a fix. Unfortunately, that fix isn't enough
to make the program type check. Partly, there's an internal error, but
that's a missing case that will take work to support properly.

We can do better with the error message as well, by special casing ...
in ->*, I think.

I don't, however, get the unbound identifier error that is in your
screenshot. I just got the error message from your original post. Can
you send the exact program that produced the error in the screenshot?


On Tue, Nov 18, 2014 at 11:54 AM, Matthias Felleisen
<matthias at ccs.neu.edu> wrote:
> On Nov 18, 2014, at 11:34 AM, Sam Tobin-Hochstadt <samth at cs.indiana.edu> wrote:
>> On Tue, Nov 18, 2014 at 10:45 AM, Matthias Felleisen
>> <matthias at ccs.neu.edu> wrote:
>>> It's quite possible that this is Eli's bug again, but boy this causes headaches:
>>>> Type Checker: parse error in type;
>>>> type variable must be used with ...
>>>>  variable: Y in: Y
>>> And it points precisely to where Y is followed by ...
>> The problem here is that you're using ->* without using the syntax of
>> ->*.  Fortunately, this program doesn't need ->* at all.
>> Unfortunately, I don't know how to make this function type check yet,
>> but I'll keep playing with it.
> Are you blaming the victim here? Please run what I send out and experience how the type checker barfs on you. This is a bug report.

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