[GHC] #12718: Segmentation fault, runtime representation polymorphism

[GHC]

#12718: Segmentation fault, runtime representation polymorphism
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHCi crash        |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #12779            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by osa1):

 rwbarton pointed out in #12779 that argument of `isTrue#` should be `0#`
 or `1#`. The documentation also says the same thing in different words:

 {{{#!haskell
 {-# INLINE isTrue# #-}
 -- | Alias for 'tagToEnum#'. Returns True if its parameter is 1# and False
 --   if it is 0#.
 isTrue# :: Int# -> Bool   -- See Note [Optimizing isTrue#]
 isTrue# x = tagToEnum# x
 }}}

 So maybe this is expected and we can close this ticket and #12779.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12718#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler