[GHC] #11011: Add type-indexed type representations (`TypeRep a`)

[GHC]

#11011: Add type-indexed type representations (`TypeRep a`)
-------------------------------------+-------------------------------------
        Reporter:  bjmprice          |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:
      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:                    |
-------------------------------------+-------------------------------------

Comment (by goldfire):

 We could have `Data.Typeable.Indexed`, but then when the un-indexed
 version is deprecated and gone, we'll be left with an awkward module name.
 I think it will be straightforward enough to deprecate `Data.Typeable` and
 have a comment (appearing in Haddock too, of course) that
 `Data.Reflection` is the new module name. (The need to rename aside, I
 think `Data.Reflection` is superior to `Data.Typeable`.)

 Very sadly, `Data.Reflection` is taken, by the `reflection` package, which
 is in active use. `GHC.Reflection`? (Aside: is there a concrete rule
 separating out `GHC.` modules from `Data.` ones? And should my new
 `Data.Kind` really be `GHC.Kind`?)

 Or perhaps we start a new top-level module prefix and go with
 `Type.Reflection`. Maybe someday `Data.Type.Equality` and friends will
 lose the `Data` part, too.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11011#comment:33>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler