[Haskell-cafe] How to expose if a constraint is satisfiable

David Kraeutmann kane at kane.cx
Mon May 7 18:29:24 UTC 2018

Correct. That instance won't work as expected.

On 5/7/2018 8:21 PM, Brandon Allbery wrote:
> On Mon, May 7, 2018 at 7:50 AM, Clinton Mead <clintonmead at gmail.com 
> <mailto:clintonmead at gmail.com>> wrote:
>     class Num t => MyNum t where
>       type IsNum t
>     instance Num t => MyNum t where
>       type IsNum t = Satisfied
> This looks wrong to me: given how instance resolution works, I'd 
> expect this to match every type and produce Satisfied, and later 
> rejection based on the context wouldn't affect it. But I could well be 
> thinking about it incorrectly.
> -- 
> brandon s allbery kf8nh sine nomine associates
> allbery.b at gmail.com <mailto:allbery.b at gmail.com> 
> ballbery at sinenomine.net <mailto:ballbery at sinenomine.net>
> unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
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