Excellent! On Aug 5, 2016 2:32 PM, "Edward Kmett" wrote:

Done and done! Retroactively. How is that for service? =)

-Edward

On Fri, Aug 5, 2016 at 2:08 PM, David Feuer wrote:

...

I know there's been some discussion about letting users select the deriving mechanism they want, but I'd like to propose a separate tweak to the defaults. Specifically, it's annoying to have to use three pragmas to let me write

newtype Foo f a = Foo (f a) deriving (Functor, Foldable, Traversable) data Bar f a = Bar (f a) deriving (Functor, Foldable, Traversable)

and more annoying still that I'll end up with Foldable and Functor instances for Foo that may be much worse than GND-derived ones.

The tweaks I'm after:

1. Prefer GND to the built-in derivations for Functor and Foldable, and probably also Eq and Ord. 2. Make DeriveTraversable imply DeriveFunctor and DeriveFoldable.

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