[GHC] #3092: algebraic data types can be extended by data instance declarations

[GHC]

#3092: algebraic data types can be extended by data instance declarations
-----------------------------+----------------------------------------------
Reporter:  jeltsch           |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  6.10.1            |       Severity:  normal          
Keywords:                    |       Testcase:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
-----------------------------+----------------------------------------------
 The following program is accepted by GHC:
 {{{
 {-# LANGUAGE TypeFamilies #-}

 data T a = C

 data instance T Int = CInt

 data instance T Bool = CBool
 }}}
 I think, it shouldn’t.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3092>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler