[Haskell-cafe] Data.Data and OverlappingInstances

[Brandon Allbery]

On Thu, Aug 9, 2012 at 6:00 AM, Timo von Holtz <timo.v.holtz at gmail.com>wrote:

> instance Num a => Test a where
>   foo = return 1
>
> instance Test Int where
>   foo = return 2
>
>
Erm, this isn't going to work anyway, is it?  I think the first instance
matches all types and then throws an error if the result isn't an instance
of Num?

-- 
brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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