"case" of an empty type should have no branches

Hi. Why the following code does not work?

data Empty quodlibet :: Empty -> a quodlibet x = case x of "parse error (possibly incorrect indentation)"

This works in Coq, for instance. Demand for empty types is not big, but they are useful for generating finite types:

Empty ≅ {} Maybe Empty ≅ {0} Maybe (Maybe Empty) ≅ {0, 1} Maybe (Maybe (Maybe Empty)) ≅ {0, 1, 2} etc. Number of 'Maybe's = number of elements. I can replace @Maybe Empty@ with @()@, but this adds some complexity.