Proposal: derive Typeable for Data.Monoid types

Roman Cheplyaka roma at
Tue May 27 08:42:30 UTC 2014

* Herbert Valerio Riedel <hvr at> [2014-05-27 10:36:46+0200]
> On 2014-05-27 at 08:31:14 +0200, Roman Cheplyaka wrote:
> > I was surprised to find out that wrappers like Last do not have Typeable
> > instances. Let's add them.
> Fyi, Data.Monoid has been given a `{-# LANGUAGE AutoDeriveTypeable #-}`
> in
> which should take care of not forgetting a 'deriving Typeable' in the
> future for any new entities defined in Data.Monoid.

Cool! I take it this is already solved in HEAD, then? Any reason not to enable
AutoDeriveTypeable for the whole base (and other core packages)?

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