Yes! In fact, the usual way to define bottom in a programming language with a fixpoint operator is 'fix id'. It's not appropriate to call NIL/NULL bottom, beca

Yes! In fact, the usual way to define bottom in a programming language with a fixpoint operator is 'fix id'. It's not appropriate to call NIL/NULL bottom, because it is a real value and we can always do computation on it (if var == NIL). Because always detecting bottom is equivalent to the halting problem, we lose. Of course, GHC will sometimes raise a NonTermination exception ;-)