[GHC] #13637: Printing type operators adds extraneous parenthesis

[GHC]

#13637: Printing type operators adds extraneous parenthesis
-------------------------------------+-------------------------------------
           Reporter:  darchon        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1-rc2
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Given the code:

 {{{
 {-# LANGUAGE TypeOperators #-}

 type name ::: a = a

 f :: Int ::: Int -> Int
 f = id
 }}}

 In GHCi-8.0.2 I get:

 {{{
 >>> :t f
 f :: Int ::: Int -> Int
 }}}

 But in GHCi-8.2.0.20170427 I get:

 {{{
 >>> :t f
 f :: (Int ::: Int) -> Int
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13637>
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