[GHC] #7102: Type family instance overlap accepted in ghci

[GHC]

#7102: Type family instance overlap accepted in ghci
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 Reporter:  exbb2                        |          Owner:                  
     Type:  bug                          |         Status:  new             
 Priority:  normal                       |      Component:  GHCi            
  Version:  7.4.1                        |       Keywords:                  
       Os:  Unknown/Multiple             |   Architecture:  Unknown/Multiple
  Failure:  GHC accepts invalid program  |       Testcase:                  
Blockedby:                               |       Blocking:                  
  Related:                               |  
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 This code works if I paste it line by line in ghci, but not if i try to
 load or compile it.
 {{{
 {-# LANGUAGE TypeFamilies #-}

 data Rec a b =  Rec {unRec :: Rec a b -> b}

 class RecursiveFun f where type A a b :: *; recurse :: f (A a b) b -> b

 instance RecursiveFun Rec where type A a b = a; recurse r = unRec r r

 instance RecursiveFun (->) where type A a b = Rec a b; recurse f = f (Rec
 f)

 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7102>
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