-- Test #3118

-- The test is quite delicate.  It aims to get 'f' to look like
--   f y = case x of
--             Red -> (y, y)
--             _ -> let v = case x of
--                             Green -> 2
--                             Blue  -> 3
--                  in (v, 5)
--
-- And now float the inner case to top level
-- so that it's not so obvious that the Red case
-- cannot occur.  This crashed GHC 6.10.
--
-- It's delicate to make the bug show up
--  (a) because it relies on not "seeing" that
--      x = Red until later.
--  (b) because dropping the Red case must happen
--      before float-out, which itself happens v early

-- In the original report, the x=Red was concealed by profiling

module T3118 where

data Colour = Red | Green | Blue


{-# NOINLINE [0] f #-}
g x = Red

x = g True

f :: Int -> (Int,Int)
f y = case x of
         Red -> (y, y)
         xx -> let v = case xx of
                          Red -> 1
                          Green -> 2
                          Blue  -> 3
                 in (v, 5)