Add instance Data a => Data (ZipList a) to base
I'm surprised this is missing. All newtypes exported from Control.Applicative share the same issue, with the exception of Const.
+1 ZipList should be no-brainer. Someone should write a patch. GHC seems to generate instances like below just fine for wrapper things too, though how often `m a` is actually Data? Well probably often enough. newtype WrappedMonad m a = WrapMonad { unwrapMonad :: m a } deriving (Data) -- instance [safe] (Typeable m, Typeable a, Data (m a)) => -- Data (WrappedMonad m a) - Oleg On 3.11.2019 16.28, Mario wrote:
I'm surprised this is missing. All newtypes exported from Control.Applicative share the same issue, with the exception of Const.
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I don't think we really need to go through the proposal process to add a
Data instance when we already have a Generic instance or vice versa.
On Sun, Nov 3, 2019, 9:29 AM Mario
I'm surprised this is missing. All newtypes exported from Control.Applicative share the same issue, with the exception of Const.
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On 2019-11-04 10:23 a.m., David Feuer wrote:
I don't think we really need to go through the proposal process to add a Data instance when we already have a Generic instance or vice versa.
What should I do instead? Open an issue? The bug tracker link on Hackage is broken, BTW. It works without the last path component. http://ghc.haskell.org/trac/ghc/newticket?component=libraries/base
You can consider this email a judgment from the base maintainer on the CLC
that it is okay to add these missing Data instances.
That should be enough to not get the issue thrown out of the ghc issue
tracker.
We already had the discussions in the CLC back a couple of years ago
approving adding missing common instances when uniquely defined. These seem
to have been missed in the previous passes.
Now we just need a patch.
-Edward
On Mon, Nov 4, 2019 at 10:29 AM Mario Blažević
On 2019-11-04 10:23 a.m., David Feuer wrote:
I don't think we really need to go through the proposal process to add a Data instance when we already have a Generic instance or vice versa.
What should I do instead? Open an issue? The bug tracker link on Hackage is broken, BTW. It works without the last path component.
http://ghc.haskell.org/trac/ghc/newticket?component=libraries/base _______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
participants (5)
-
David Feuer -
Edward Kmett -
Mario -
Mario Blažević -
Oleg Grenrus