How do I use CallStack?

[Eric Seidel]

Oh I forgot to mention that I was testing on my local branch which fixes precisely this kind of bug when the CallStack is used inside a let-binder, which is what happens in rewriteEqEvidence. 

So it looks like my patch takes care of this issue. Thanks for the report!

Sent from my iPhone

> On Dec 7, 2015, at 11:25, Richard Eisenberg <eir at cis.upenn.edu> wrote:
> 
> 
>> On Dec 7, 2015, at 2:23 PM, Eric Seidel <eric at seidel.io> wrote:
>> 
>> After staring at your bug confusedly for a few minutes, wondering why I
>> couldn't simplify it, I realized that the actual warning I was getting
>> was in *mkTcTransCo*, not rewriteEqEvidence. mkTcTransCo does not in
>> fact use a CallStack (by default) so the redundant constraint warning
>> there would be correct. If I add a call to error, everything seems to
>> check out.
>> 
>> Can you confirm?
> 
> No. I had modified mkTcTransCo to print out the call-stack, so that wasn't the problem. If you can't reproduce quickly, I'll take another look at this when I get a chance. Thanks for taking a pass.
> 
> Richard
> 
>> 
>> Thanks!
>> Eric
>