[GHC] #7642: Nullary type classes

[GHC]

#7642: Nullary type classes
----------------------------------------+-----------------------------------
    Reporter:  shachaf                  |       Owner:                  
        Type:  feature request          |      Status:  new             
    Priority:  normal                   |   Milestone:                  
   Component:  Compiler (Type checker)  |     Version:  7.6.1           
    Keywords:                           |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple         |     Failure:  None/Unknown    
  Difficulty:  Unknown                  |    Testcase:                  
   Blockedby:                           |    Blocking:                  
     Related:                           |  
----------------------------------------+-----------------------------------

Comment(by simonpj):

 OK, fine.  I can't say I find the motivation very persuasive, but I agree
 in general that lifting restrictions is a Good Thing provided it does not
 have knock-on consequences. Maybe this doesn't.

 Do you feel like augmenting your patch?

  * We need an extension flag `-XNullaryTypeClases`.
  * Test the flag when needed (you know the place)
  * Document the flag in the usar manual
  * Perhaps a test case or two

 If you do that, I'll drop it in. Thanks!

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7642#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler