data-default WAS: [containers] Proposal: Change to the Data.Map Monoid

Bryan O'Sullivan bos at
Thu May 29 16:44:25 UTC 2014

On Sun, May 25, 2014 at 12:49 AM, João Cristóvão <jmacristovao at>

> But my main point here is: should we limit generic deriving of
> instances because some people don't see value in it for themselves,
> given that some clearly do?

Yes, of course we should. The whole point of having typeclasses is that the
instances should make sense for everyone. The bar for introducing both
typeclasses and especially automatically derived instances is a whole lot
higher than "works for me, sometimes".
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