[GHC] #1968: data family + GADT = Non-exhaustive patterns in function choose_univs

[GHC]

#1968: data family + GADT = Non-exhaustive patterns in function choose_univs
----------------------------------------+-----------------------------------
    Reporter:  Remi                     |       Owner:                                    
        Type:  bug                      |      Status:  new                               
    Priority:  normal                   |   Milestone:                                    
   Component:  Compiler (Type checker)  |     Version:  6.9                               
    Severity:  normal                   |    Keywords:  data type family GADT choose_univs
  Difficulty:  Unknown                  |    Testcase:                                    
Architecture:  Unknown                  |          Os:  Unknown                           
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 My very first attempt at playing with data type families + GADTs went
 wrong, using 6.9.20071209:

 {{{
 {-# LANGUAGE TypeFamilies, GADTs #-}

 data family HiThere a :: *

 data instance HiThere () where
     HiThere :: HiThere ()
 }}}

 {{{
 GHCi, version 6.9.20071209: http://www.haskell.org/ghc/  :? for help
 Loading package base ... linking ... done.
 [1 of 1] Compiling Main             ( bar.hs, interpreted )
 *** Exception: typecheck/TcTyClsDecls.lhs:(878,4)-(884,42): Non-exhaustive
 patterns in function choose_univs
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1968>
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