[GHC] #13788: TypeInType fails to compile old code

[GHC]

#13788: TypeInType fails to compile old code
-------------------------------------+-------------------------------------
        Reporter:  br1               |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by goldfire):

 This isn't an issue with `TypeInType`, per se, but with `PolyKinds`, which
 originally added kind generalization. (You'll find that compiling with
 just `PolyKinds` causes the same effect as you're observing with
 `TypeInType`.)

 Many of the language "extensions" have the potential to break code. For
 example, `OverloadedStrings` can cause declarations like `x = length "hi"`
 to fail, because GHC can no longer tell what type `"hi"` should be.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13788#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler