TH changes for ghc 8.0

[Erik Hesselink]

On 12 April 2016 at 07:36, Matthias Fischmann <mf at zerobuzz.net> wrote:
> On Tue, Apr 12, 2016 at 02:22:23PM +1000, Erik de Castro Lopo wrote:
>> Date: Tue, 12 Apr 2016 14:22:23 +1000
>> From: Erik de Castro Lopo <mle+hs at mega-nerd.com>
>> To: ghc-devs at haskell.org
>> Subject: TH changes for ghc 8.0
>>
>> Hi all,
>>
>> I'm working on updating persistent-template for ghc-8.0 and reading the
>> migration guide:
>>
>>     https://ghc.haskell.org/trac/ghc/wiki/Migration/8.0#template-haskell-2.11.0.0
>>
>> specifically the bit that says:
>>
>> > * the DataD, NewtypeD, DataInstD, and NewtypeInstD constructors have a new
>> >   field `Maybe Kind` (#10828), and take a `CxtQ` instead of a `[Name]` for
>> >   the derived classes (#10819). If you don't know what to do, use `Nothing`
>> >   for the kind signature, and `cxt []` for the derived classes.
>>
>> Using `Nothing` as suggested is working out well enough, but I'm a bit befuddled
>> by the change from `[Name]` to `CtxQ` and the usage of `ctx []`. I can't seem to
>> find *any* function named `ctx`.
>
> the docs say `cxt`, not `ctx`.
>
> not sure what that means either.  (-:

That function does exist for me in rc2:

cxt :: [PredQ] -> CxtQ

Erik