[GHC] #14796: Pretty Printing: GHC doesn't parenthesise (() :: Constraint)

[GHC]

#14796: Pretty Printing: GHC doesn't parenthesise (() :: Constraint)
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
                                     |  TypeApplications
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #14808            |  Differential Rev(s):  Phab:D4408
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ryan Scott <ryan.gl.scott@…>):

 In [changeset:"99c556d2bb0594fd718622906168d2ea25a0bf06/ghc"
 99c556d2/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="99c556d2bb0594fd718622906168d2ea25a0bf06"
 Parenthesize (() :: Constraint) in argument position

 Summary:
 A simple oversight in the pretty-printer lead to a special
 case for `() :: Constraint` not being parenthesized correctly when
 used in an argument position. Easily fixed with a `maybeParen`.

 Test Plan: make test TEST=T14796

 Reviewers: alanz, goldfire, bgamari, simonpj

 Reviewed By: bgamari, simonpj

 Subscribers: simonpj, rwbarton, thomie, carter

 GHC Trac Issues: #14796

 Differential Revision: https://phabricator.haskell.org/D4408
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14796#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler