[GHC] #5412: dataTypeConstrs gives unhelpful error message

[GHC]

#5412: dataTypeConstrs gives unhelpful error message
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        Reporter:  NeilMitchell      |            Owner:  klangner
            Type:  bug               |           Status:  patch
        Priority:  normal            |        Milestone:  7.6.2
       Component:  libraries/base    |          Version:  7.1
      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 nomeata):

 Case 1.
 A better error message here would be `"Data.Data.gunfold: Constructor " ++
 show c ++ " is not of type Char"`. But if you don’t feel like working on
 that class of error message right now you can concentrate on the others
 and skip these for now.

 Case 2.
 Sounds good. Or maybe `"Data.Data.repConstr: The given ConstrRep does not
 fit to the given DataType"`, possibly extended with actually showing both
 parameters, or using `dataTypeName`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5412#comment:15>
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