EitherIO futzing about.hs

-- For context, see
-- https://github.com/kqr/gists/blob/master/articles/gentle-introduction-monad-transformers.md#introducing-side-effects

userLogin :: EitherIO LoginError Text
userLogin = do
  token <- getToken
  case token of
    Right domain -> liftIO domain
    left -> liftEither left

-- Errors loading:

*Main λ > :l EmailAddr.hs
[1 of 1] Compiling Main             ( EmailAddr.hs, interpreted )

EmailAddr.hs:60:5:
    Couldn't match expected type ‘Text’
                with actual type ‘Either t0 (IO Text)’
    In the pattern: Right domain
    In a case alternative: Right domain -> liftIO domain
    In a stmt of a 'do' block:
      case token of {
        Right domain -> liftIO domain
        left -> liftEither left }

EmailAddr.hs:61:24:
    Couldn't match expected type ‘Either LoginError Text’
                with actual type ‘Text’
    In the first argument of ‘liftEither’, namely ‘left’
    In the expression: liftEither left
Failed, modules loaded: none.
Prelude λ >