[GHC] #3647: unify handling and error messages for -X vs. {-#LANGUAGE ...#-} pragmas/extensions

[GHC]

#3647: unify handling and error messages for -X vs. {-#LANGUAGE ...#-}
pragmas/extensions
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Reporter:  eflister                                          |          Owner:                   
    Type:  feature request                                   |         Status:  new              
Priority:  normal                                            |      Component:  Compiler (Parser)
 Version:  6.10.4                                            |       Severity:  trivial          
Keywords:  language pragma extensions error message warning  |       Testcase:                   
      Os:  Unknown/Multiple                                  |   Architecture:  Unknown/Multiple 
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 it's easy to accidentally cut and paste a -XExtentionName from a ghc error
 message into one's  {-#LANGUAGE ...#-} pragma, and then one has to track
 down the problem when that doesn't work.  it would be nice if
 -XExtentionName were accepted in the pragma list.  even though -X is ghc
 specific, i don't see that it hurts anything to be lenient in the pragma
 format accepted (a warning could be produced to indicate that the program
 will not be portable).  also, the ghc error message indicating that an
 extension should be added should print out a message that would make for
 easy cut and paste without modification into *either* one's language
 pragma or command line -X extension args.  see
 http://hackage.haskell.org/trac/ghc/ticket/3616#comment:8.

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3647>
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