[GHC] #11432: Cannot export operator newtype

[GHC]

#11432: Cannot export operator newtype
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        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):
       Wiki Page:                    |
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Comment (by skvadrik):

 I think `-.->` is lexically `@varsym` (and `VARSYM` parser) and `(-.->)`
 is parsed as `'(' VARSYM ')'`:
 {{{
 ...
     qcname
     -> qvar
     -> '(' varsym ')'
     -> '(' varsym_no_minus ')'
     -> '(' VARSYM ')'
 }}}
 I don't know yet why it did work before commit
 ffc21506894c7887d3620423aaf86bc6113a1071, but I suspect the answer is
 hidden not in grammar, but in the way data constructors are (were?)
 "fixed" after parsing to become type constructors.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11432#comment:20>
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