[Haskell-cafe] Tagged instances for Aeson overlapped

[Dmitry Olshansky]

Whoops from me also...

It was mine instance. Sorry for the noise.

Thanks!

2016-03-07 18:24 GMT+03:00 Adam Bergmark <adam at bergmark.nl>:

>
> Whoops, didn’t reply-all!
>
> One instance is in Data.Aeson.Types.Instances, where are you getting the
> other one from?
>
> Adam Bergmark
>
>
> On Mon 07 Mar 2016 at 15:37 Dmitry Olshansky <Dmitry Olshansky
> <Dmitry+Olshansky+%3Colshanskydr at gmail.com%3E>> wrote:
>
>> Hello,
>>
>> I tried to compile my project with GHC 8 (from HEAD).
>>
>> And I got
>>
>>>     • Overlapping instances for
>>> aeson-0.11.1.0:Data.Aeson.Types.Class.ToJSON
>>> ...
>>>         arising from a use of ‘serve’
>>>       Matching instances:
>>>         two instances involving out-of-scope types
>>>           instance aeson-0.11.1.0:Data.Aeson.Types.Class.ToJSON b =>
>>>                    aeson-0.11.1.0:Data.Aeson.Types.Class.ToJSON
>>>                      (Data.Tagged.Tagged a b)
>>>             -- Defined in ‘aeson-0.11.1.0:Data.Aeson.Types.Instances’
>>>           instance forall k x (r :: k).
>>>                    aeson-0.11.1.0:Data.Aeson.Types.Class.ToJSON x =>
>>>                    aeson-0.11.1.0:Data.Aeson.Types.Class.ToJSON
>>>                      (Data.Tagged.Tagged r x)
>>
>>
>> One of instances should be removed probably.
>> I suppose that instance for removing should be instance in Data.Tagged.
>> But version in Aeson should be PolyKinded.
>>
>> What do you think?
>>
>> Best regards,
>> Dmitry
>>
>> _______________________________________________
>> Haskell-Cafe mailing list
>> Haskell-Cafe at haskell.org
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/haskell-cafe/attachments/20160307/78b0d02e/attachment.html>