constraint deduction bug?

[Richard Eisenberg]

It certainly looks trivial to me.

Richard

On Mar 21, 2013, at 7:59 PM, Gabor Greif <ggreif at gmail.com> wrote:

> In context of a bigger source file I got this error from GHC (HEAD)
> 
>    Could not deduce (Intersect
>                        [KeySegment] (BuriedUnder sub k ('Empty
> [KeySegment])) inv
>                      ~ 'Empty [KeySegment])
>    from the context (Intersect
>                        [KeySegment] (BuriedUnder sub k ('Empty
> [KeySegment])) inv
>                      ~ 'Empty [KeySegment])
>      bound by a pattern with constructor
>                 Nil :: forall (k :: BOX). Sing (Inventory k) ('Empty k),
>               in a pattern binding in
>                    'do' block
> 
> Can somebody confirm that this constraint should be trivially deducible from
> the context?
> 
> Then I'll try to come up with a reduced repro case.
> 
> Cheers,
> 
> 	Gabor
> 
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