[GHC] #9299: GHCi type inference error

[GHC]

#9299: GHCi type inference error
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        Reporter:  erikd             |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  GHCi              |          Version:  7.8.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  Other             |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by erikd):

 From #ghc on Freenode:

 {{{
 <dolio> Here's my theory.
 <dolio> The difference between GHC and GHCi is extended defaulting.
 <dolio> InputSource is only eligible for extended defaulting, not regular
 defaulting.
 <dolio> So, when loaded in ghci, it's getting defaulted, which is
 ambiguous.
 <dolio> Whereas in ghc, it doesn't get defaulted, and correctly gets tied
 to the stdin variable in the signature of conduitProcess.
 <dolio> None of the instances for InputSource are on the defaulting list,
 which is why it's ambiguous.
 <dolio> I don't understand why defaulting would kick in, though.
 <dolio> It's like it's overly aggressive.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9299#comment:1>
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