[GHC] #8567: Poor error message when GeneralizedNewtypeDeriving fails

[GHC]

#8567: Poor error message when GeneralizedNewtypeDeriving fails
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        Reporter:  goldfire          |            Owner:  nomeata
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.7
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by Joachim Breitner <mail@…>):

 In [changeset:"1791ea0abf446bc7221f713d715f4bf87dc6af47/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="1791ea0abf446bc7221f713d715f4bf87dc6af47"
 Print nicer error message for Coercible errors

 It now reads

    Could not coerce from ‛S a’ to ‛S (NT a)’

 and does not mention Coercible any more (as discussed in #8567).
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8567#comment:4>
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