[GHC] #836: rebindable if-then-else syntax

[GHC]

#836: rebindable if-then-else syntax
----------------------------------+-----------------------------------------
    Reporter:  nibro              |        Owner:  SamAnklesaria
        Type:  feature request    |       Status:  new          
    Priority:  normal             |    Milestone:  _|_          
   Component:  Compiler (Parser)  |      Version:  6.13         
    Keywords:                     |     Testcase:  N/A          
   Blockedby:                     |   Difficulty:  Unknown      
          Os:  Unknown/Multiple   |     Blocking:               
Architecture:  Unknown/Multiple   |      Failure:  None/Unknown 
----------------------------------+-----------------------------------------

Comment(by batterseapower):

 Maybe you could only use the ifThenElse if the type of the if branches has
 a lifted kind?

 Alternatively:

 {{{
 if e1 then e2 :: Int# else e3 :: Int# ==> case (ifThenElse e1 True False)
 of True -> e2; False -> e2
 }}}

 However, I'm not sure if this is a useful translation. It might be clearer
 if I knew what the use cases for rebindable ifThenElse were.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/836#comment:22>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler