[GHC] #11952: automatic show instance generating loop

[GHC]

#11952: automatic show instance generating loop
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        Reporter:  maxigit           |                Owner:
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:  invalid           |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by kosmikus):

 * status:  new => closed
 * resolution:   => invalid


Comment:

 An empty instance for `show` is not automatic. It uses the default
 definitions, which
 are defined in terms of each other.

 You can use `StandaloneDeriving` and say
 {{{
 deriving instance Show (A Valid)
 deriving instance Show (A Invalid)
 }}}
 instead and it will work just fine.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11952#comment:1>
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