never executed always true always false
    1 {-# LANGUAGE RecordWildCards #-}
    2 
    3 data Foo = Foo
    4   { foo1 :: Int
    5   , foo2 :: Int
    6   }
    7 
    8 showFoo :: Foo -> IO ()
    9 showFoo Foo{..} = print (foo1, foo2)
   10 
   11 main = showFoo (Foo 1 2)