we'd still like foo to be inlined if rhs is small. This won't happen
with foo = bar.
-Not CSE-ing inside INLLINE also solves an annoying bug in CSE. Consider
+Not CSE-ing inside INLINE also solves an annoying bug in CSE. Consider
a worker/wrapper, in which the worker has turned into a single variable:
$wf = h
f = \x -> ...$wf...