[GHC] #13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without FlexibleInstances.

[GHC]

#13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without
FlexibleInstances.
-------------------------------------+-------------------------------------
        Reporter:  Hjulle            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  low               |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:  newcomer
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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Changes (by RyanGlScott):

 * keywords:   => newcomer


Comment:

 This should be straightforward to fix: it would just require some tweaking
 of the
 [http://git.haskell.org/ghc.git/blob/6a9b9b431dcc94849d14c13639eb2f713e5aa1f4:/compiler/typecheck/TcValidity.hs#l1116
 tcInstHeadTyAppAllTyVars] function to allow something headed by a `LitTy`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13833#comment:1>
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