+ -- Arity info
+ new_arity = exprArity rhs
+ new_bndr_info = idInfo new_bndr `setArityInfo` new_arity
+
+ -- Unfolding info
+ -- Add the unfolding *only* for non-loop-breakers
+ -- Making loop breakers not have an unfolding at all
+ -- means that we can avoid tests in exprIsConApp, for example.
+ -- This is important: if exprIsConApp says 'yes' for a recursive
+ -- thing, then we can get into an infinite loop
+
+ -- Demand info
+ -- If the unfolding is a value, the demand info may
+ -- go pear-shaped, so we nuke it. Example:
+ -- let x = (a,b) in
+ -- case x of (p,q) -> h p q x
+ -- Here x is certainly demanded. But after we've nuked
+ -- the case, we'll get just
+ -- let x = (a,b) in h a b x
+ -- and now x is not demanded (I'm assuming h is lazy)
+ -- This really happens. Similarly
+ -- let f = \x -> e in ...f..f...
+ -- After inlining f at some of its call sites the original binding may
+ -- (for example) be no longer strictly demanded.
+ -- The solution here is a bit ad hoc...
+ info_w_unf = new_bndr_info `setUnfoldingInfo` unfolding
+ `setWorkerInfo` wkr
+
+ final_info | isEvaldUnfolding unfolding = zapDemandInfo info_w_unf `orElse` info_w_unf
+ | otherwise = info_w_unf
+
+ final_id = new_bndr `setIdInfo` final_info
+\end{code}