[GHC] #12374: Type holes show incorrect type in GHCi

[GHC]

#12374: Type holes show incorrect type in GHCi
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        Reporter:  crockeea          |                Owner:
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  GHCi              |              Version:  8.0.1
      Resolution:  invalid           |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  warning at compile-time            |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  9479, 9091        |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by simonpj):

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


Comment:

 GHCi has type-class defaulting rules, described
 [http://downloads.haskell.org/~ghc/master/users-guide/ghci.html#type-
 defaulting-in-ghci here in the manual].  I think that's all that is
 happening here, so it's working as specified.

 Maybe the specification isn't right, but defaulting `Show` to `()` was
 driven by examples like
 {{{
 > show []
 }}}
 I'll close as invalid for now.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12374#comment:1>
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