[GHC] #13177: Give Data.Functor.* its lifted unit and void

[GHC]

#13177: Give Data.Functor.* its lifted unit and void
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.0.1
      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:                    |
-------------------------------------+-------------------------------------
Description changed by Iceland_jack:

@@ -18,2 +18,2 @@
- Packages like [https://hackage.haskell.org/package/linear linear] provide
- basically the same lifted functors
+ The package [https://hackage.haskell.org/package/linear linear] provides
+ the lifted unit functor
@@ -22,2 +22,1 @@
- data    V0 a = V0
- newtype V1 a = V1 a
+ data V0 a = V0

New description:

 `GHC.Generics` has

 {{{#!hs
 data U1 a = U1
 data V1 a
 }}}

 They are simple but why are they not present in the `Data.Functor`
 hierarchy along with functions like (from
 [https://hackage.haskell.org/package/one-liner-0.7/docs/src/Generics-
 OneLiner-Internal.html one-liner])

 {{{#!hs
 absurd :: V1 a -> b
 absurd = \case
 }}}

 The package [https://hackage.haskell.org/package/linear linear] provides
 the lifted unit functor

 {{{#!hs
 data V0 a = V0
 }}}

 if they or those from `GHC.Generics` should be preferred it could be added
 to the documentation.

--

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13177#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler