[GHC] #9901: Error message: f is applied to two arguments, but its type has only two (sic)

[GHC]

#9901: Error message: f is applied to two arguments, but its type has only two
(sic)
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        Reporter:  zardoz            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.8.3
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by simonpj):

 Can you offer an example that does not depend on `lens` with its zillions
 of dependencies?

 Usually you can just write down the types of the imports, thus:
 {{{
 preview :: <type of preview>
 preview = error "urk"
 }}}

 Also is the `UnicodeSyntax` significant.

 Thakns

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9901#comment:4>
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