This is now done: commit b1fc62762c56ccaa536d41b49a2aa0866e7420f7 Author: Austin Seipp Date: Thu May 30 07:33:01 2013 -0500 Enable PolyKinds for Control.Category. This change will allow us to make various new things instances of Category, such as promoted tuples. Original discussion from libraries@haskell.org: http://www.haskell.org/pipermail/libraries/2012-August/018268.html Fell off the radar. No complaints in the 2 week period since being brought up again: http://www.haskell.org/pipermail/libraries/2013-May/019845.html Patch from Edward Kmett (essentially.) Authored-by: Edward Kmett Signed-off-by: Austin Seipp On Thu, May 16, 2013 at 12:02 PM, Austin Seipp wrote:

Very well then. If there are no objections in the typical 2wk time frame*, I will craft a patch to base and commit it to fix this.

* Technically, some might consider this proposal open for 9 months. I'm new to library changes however, so I'll go by all the rules as I should. :)

On Thu, May 16, 2013 at 11:02 AM, Edward Kmett wrote:

...

As noted by Simon, the bound on that should be >= 706 though.

On Thu, May 16, 2013 at 12:02 PM, Austin Seipp wrote:

...

Also, apologies for reviving a thread. I also did not include Edward's original message for better context. It is inline below.

-------------------------- Would it be possible to add something like

{-# LANGUAGE CPP #-} #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 704 {-# LANGUAGE PolyKinds #-} #endif

to the top of Control.Category before the 7.6.1 final release?

Control.Category.Category is pretty much the only type in base that directly benefits from PolyKinds without any code changes, but without enabling the extension there nobody can define categories for kinds other than *, and most interesting categories actually have more exotic kinds.

I only noticed that it wasn't there in the release candidate just now.

-Edward Kmett --------------------------

-- Regards, Austin - PGP: 4096R/0x91384671

-- Regards, Austin - PGP: 4096R/0x91384671

-- Regards, Austin - PGP: 4096R/0x91384671