isTrue# doesn't work in ghci anymore
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 (closed) is segfaulting. I'm currently working on this.
isTrue#
is failing in 8.0.1 too.