[GHC] #11535: Derived instance of Read/Show causes runtime exception for infix Unicode value constructors

[GHC]

#11535: Derived instance of Read/Show causes runtime exception for infix Unicode
value constructors
-------------------------------------+-------------------------------------
        Reporter:  nushio            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:  unicode
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #1544, #11529     |  Differential Rev(s):  Phab:D1884
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"1ef7add01ead4cbe065297f68306d9bc4b456156/ghc" 1ef7add/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1ef7add01ead4cbe065297f68306d9bc4b456156"
 Add test (only) to assure that #11535 is fixed

 Ticket #11535 dealt with derived Read instances of infix Unicode
 value constructors. GHC 7.10.3 used to derive (Read/Show)
 instances so that `read . show` for values of such types had no
 parse.

 The issue has been fixed by other compiler update. This patch
 adds only tests, so that derived instance of Read/Show for infix
 Unicode value constructors has correct parse, satisfying Haskell
 2010 Specification.

 Resolves: #11535

 Test Plan: `make test TEST=T11535`

 Reviewers: austin, rwbarton, thomie, bgamari

 Reviewed By: rwbarton, thomie, bgamari

 Subscribers: rwbarton, thomie

 Projects: #ghc

 Differential Revision: https://phabricator.haskell.org/D1884

 GHC Trac Issues: #11535
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11535#comment:9>
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