[GHC] #10018: Cannot define custom fixity for infix data constructors in GHCi

[GHC]

#10018: Cannot define custom fixity for infix data constructors in GHCi
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  GHCi              |                 Version:  7.10.1-rc2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #9830             |  Differential Revisions:
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Comment (by RyanGlScott):

 I'm not sure if this is related, but when I tried declaring the above data
 type with {{{infixr 5 :@:}}} first, GHCi fails to parse it:

 {{{
 $ ghci
 GHCi, version 7.10.1: http://www.haskell.org/ghc/  :? for help
 λ> infixr 5 :@:; data Infix a b = a :@: b deriving Show

 <interactive>:2:1: parse error on input ‘infixr’
 }}}

 It's possible that this bug wouldn't manifest itself if the {{{infixr}}}
 declaration appeared first, but GHCi won't allow this in the first place,
 so it's impossible to tell.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10018#comment:4>
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