[GHC] #12779: isTrue# doesn't work in ghci anymore

[GHC]

#12779: isTrue# doesn't work in ghci anymore
-------------------------------------+-------------------------------------
           Reporter:  osa1           |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  GHCi           |           Version:  8.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #12718
Differential Rev(s):                 |         Wiki Page:
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 {{{#!haskell
 GHCi, version 8.1.20161028: http://www.haskell.org/ghc/  :? for help
 Prelude> :set -XMagicHash
 Prelude> :m + GHC.Types
 Prelude GHC.Types> isTrue# 123#
 True
 Prelude GHC.Types> [1]    3181 segmentation fault  ghc-stage2
 --interactive
 }}}

 This is also the reason why #12718 is segfaulting. I'm currently working
 on this.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12779>
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