[GHC] #7156: "Pattern match on GADT" error for non-GADT

[GHC]

#7156: "Pattern match on GADT" error for non-GADT
---------------------------------------------------------------+------------
    Reporter:  ryani                                           |       Owner:                  
        Type:  bug                                             |      Status:  new             
    Priority:  normal                                          |   Milestone:                  
   Component:  Compiler (Type checker)                         |     Version:  7.0.4           
    Keywords:  GADTs, TypeFamilies, ExistentialQuantification  |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple                                |     Failure:  None/Unknown    
  Difficulty:  Unknown                                         |    Testcase:                  
   Blockedby:                                                  |    Blocking:                  
     Related:                                                  |  
---------------------------------------------------------------+------------
Changes (by simonpj):

  * difficulty:  => Unknown


Comment:

 Urgh. I'm not sure what you really want to happen here.  Do you want a
 different error message depending on the syntax used when T was declared?
 Or, since `g` doesn't use any strange syntax, do you want it to be
 accepted without any flags at all?   Or do you want the error message to
 be worded differently?  It's not very clear to me.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7156#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler