[GHC] #15018: Bump base's version number to 4.12.0.0 in HEAD

[GHC]

#15018: Bump base's version number to 4.12.0.0 in HEAD
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  libraries         |              Version:  8.5
  (other)                            |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by RyanGlScott:

Old description:

> Currently, `base` sits at version `4.11.0.0` in HEAD (which is the same
> version of `base` as shipped with GHC 8.4.1). This is making it difficult
> to adapt certain Hackage libraries to recent changes in `base`, such as
> moving `Data.Functor.Contravariant` into `base` (see the discussion
> [https://github.com/ekmett/contravariant/issues/44 here]).
>
> Before we can do this, here is a list of libraries that will need to have
> their upper version bounds on `base` bumped from `< 4.12` to `< 4.13`:
>
> * `array`
> * `deepseq`
> * `directory`
> * `filepath`
> * `ghc-boot-th` (in-place)
> * `ghc-compat` (in-place)
> * `ghci` (in-place)
> * `haddock`
> * `haskeline`
> * `hpc`
> * `parallel`
> * `parsec`
> * `primitive`
> * `process`
> * `stm`
> * `template-haskell` (in-place)
> * `terminfo`
>
> Some of these can be changed in-place, while others will require
> downstream changes. I'll update this ticket as I progress.

New description:

 Currently, `base` sits at version `4.11.0.0` in HEAD (which is the same
 version of `base` as shipped with GHC 8.4.1). This is making it difficult
 to adapt certain Hackage libraries to recent changes in `base`, such as
 moving `Data.Functor.Contravariant` into `base` (see the discussion
 [https://github.com/ekmett/contravariant/issues/44 here]).

 Before we can do this, here is a list of libraries that will need to have
 their upper version bounds on `base` bumped from `< 4.12` to `< 4.13`:

 * `array`
 * `deepseq`
 * `directory`
 * `filepath`
 * `ghc-boot-th` (in-place)
 * `ghc-compat` (in-place)
 * `ghci` (in-place)
 * `haddock`
 * `haskeline`
 * `hpc`
 * `parsec`
 * `process`
 * `stm`
 * `template-haskell` (in-place)
 * `terminfo`

 Some of these can be changed in-place, while others will require
 downstream changes. I'll update this ticket as I progress.

--

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15018#comment:2>
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