[GHC] #4107: Extra parens in error message's displayed code

[GHC]

#4107: Extra parens in error message's displayed code
-------------------------------+--------------------------------------------
    Reporter:  marcotmarcot    |       Owner:              
        Type:  bug             |      Status:  new         
    Priority:  normal          |   Component:  Compiler    
     Version:  6.13            |    Keywords:              
          Os:  Linux           |    Testcase:              
Architecture:  x86_64 (amd64)  |     Failure:  None/Unknown
-------------------------------+--------------------------------------------
 In the code

 f :: Bool a => a
 f = True

 $ ghc13 --make teste
 The error message displayed is:

 [1 of 1] Compiling Main             ( teste.hs, teste.o )

 teste.hs:1:6:
     Type constructor `Bool' used as a class
     In the type signature for `f': f :: (Bool a) => a

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4107>
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