never executed always true always false

    1 {-
    2 (c) The University of Glasgow, 2000-2006
    3 -}
    4 
    5 {-# LANGUAGE MagicHash, UnboxedTuples #-}
    6 
    7 module GHC.Utils.IO.Unsafe
    8    ( inlinePerformIO,
    9    )
   10 where
   11 
   12 import GHC.Prelude ()
   13 
   14 import GHC.Exts
   15 import GHC.IO   (IO(..))
   16 
   17 -- Just like unsafeDupablePerformIO, but we inline it.
   18 {-# INLINE inlinePerformIO #-}
   19 inlinePerformIO :: IO a -> a
   20 inlinePerformIO (IO m) = case m realWorld# of (# _, r #)   -> r