ExpandSynsFail4.hs:11:22: error:
    Couldn't match type ‘Bool’ with ‘Int’
    Expected type: T Int
      Actual type: T Bool
    In the first argument of ‘f’, namely ‘(undefined :: T Bool)’
    In the second argument of ‘($)’, namely ‘f (undefined :: T Bool)’
    In the expression: putStrLn $ f (undefined :: T Bool)