f = \ t -> case (v `cast` co) of
V a b -> a : f t
-Exactly the same optimistaion (unrolling one call to f) will work here,
+Exactly the same optimisation (unrolling one call to f) will work here,
despite the cast. See mk_alt_env in the Case branch of libCase.
Data types
~~~~~~~~~~
-
The ``level'' of a binder tells how many
recursive defns lexically enclose the binding
A recursive defn "encloses" its RHS, not its