[GHC] #8868: Old information in Extensions to data types and type synonyms

[GHC]

#8868: Old information in Extensions to data types and type synonyms
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        Reporter:  Kinokkory          |            Owner:
            Type:  bug                |           Status:  new
        Priority:  normal             |        Milestone:  ⊥
       Component:  Documentation      |          Version:  7.6.1
      Resolution:                     |         Keywords:
Operating System:  Unknown/Multiple   |     Architecture:  Unknown/Multiple
 Type of failure:  Documentation bug  |       Difficulty:  Unknown
       Test Case:                     |       Blocked By:
        Blocking:                     |  Related Tickets:
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Changes (by Kinokkory):

 * version:  7.8.1-rc2 => 7.6.1
 * milestone:  7.8.1 => ⊥


Comment:

 I just would like to make the User's Guide faithful to the behavior of the
 GHC 7.6.*. I'm not talking about the behavior of the release candidate. (I
 believe ''symbol infix type variables'' should be legal, but I'm not
 sure.)

 The problem is whether the GHC accepts this code.
 {{{
 type T (+) = Int + Int
 f :: T Either
 f = Left 3
 liftA2 :: Arrow (~>) => (a -> b -> c) -> (e ~> a) -> (e ~> b) -> (e ~> c)
 liftA2 = ...
 }}}
 The User's Guide of GHC 7.8.1-rc1 says
   http://www.haskell.org/ghc/docs/7.8.1-rc1/html/users_guide/data-type-
 extensions.html#type-operators
   In types, an operator symbol like (+) is normally treated as a type
 variable, just like a. ... As you can see, using operators in this way is
 not very useful, and Haskell 98 does not even allow you to write them
 infix.
 So it seems that the new version's documentation have reflected the
 change.

 If GHC isn't willing to change the documentations of released versions,
 close this ticket.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8868#comment:2>
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