:: Either a b -> IO b

Fail if the given Either a b value is a Left. Use this function if a is not an instance of Show.
Lifts an Either e into Monad m with effect Throw e
Fail if the given Either a b value is a Left. Use this function if a is an instance of Show.
Return value on the Right and fail otherwise. Difference from shouldSatisfy action isRight in that expectRight will force the content of the Right to WHNF and return it. This expectation will also show the content of the Left when expectation fails.
Escalate an Either to an exception.
Return value on the Right and fail otherwise. Lifted version of expectRight.