[GHC] #3851: type family does not get expanded in ghc-6.12.1

[GHC]

#3851: type family does not get expanded in ghc-6.12.1
----------------------------------------+-----------------------------------
    Reporter:  kosmikus                 |        Owner:                           
        Type:  bug                      |       Status:  new                      
    Priority:  normal                   |    Milestone:                           
   Component:  Compiler (Type checker)  |      Version:  6.12.1                   
    Keywords:                           |   Difficulty:                           
          Os:  Unknown/Multiple         |     Testcase:                           
Architecture:  Unknown/Multiple         |      Failure:  GHC rejects valid program
----------------------------------------+-----------------------------------

Comment(by simonpj):

 Realistically 3 months.  I didn't know that multirec relied crucially on
 ''both'' type functions ''and'' GADTs in combination.  I'm pretty
 reluctant to invest the time it'd take to figure out why 6.12 isn't
 behaving the same way as 6.10 given that it's code that will be nuked
 shortly.  Maybe multirec users can stick to 6.10 for now.  That's not a
 very good answer I know.  But you are on the bleeding edge here.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3851#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler