why do this function doesn't compile (parse error):

test :: Bool -> IO ()
test foo = do
   let bar = case foo of
       True ->  "Foo";
       False -> "Bar"
   return ()

while this one does (just adding one space in front of True and False):

test :: Bool -> IO ()
test foo = do
   let bar = case foo of
        True ->  "Foo";
        False -> "Bar"
   return ()

Thanks!!

Corentin