[GHC] #11432: Cannot export operator newtype

[GHC]

#11432: Cannot export operator newtype
-------------------------------------+-------------------------------------
        Reporter:  phadej            |                Owner:  skvadrik
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.0.1-rc1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1888
       Wiki Page:                    |
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Comment (by skvadrik):

 I agree that basing compilation decisions on subtle syntax changes is bad,
 but error message
 {{{
 error: Not in scope: ‘%%’
 }}}
 which appears suddenly after GHC upgrade is obscure. I think it should at
 least suggest the cause of error and the way to fix it. Perhaps something
 like this (don't hesitate to suggest a better wording):
 {{{
 error: Not in scope: ‘%%’
     Note: if '%%' is a type constructor, add 'type' keyword: 'type (%%)'
     (requires extension TypeOperators)
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11432#comment:26>
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