+\begin{code}
+data CoreStats = CS { cs_tm, cs_ty, cs_co :: Int }
+
+plusCS :: CoreStats -> CoreStats -> CoreStats
+plusCS (CS { cs_tm = p1, cs_ty = q1, cs_co = r1 })
+ (CS { cs_tm = p2, cs_ty = q2, cs_co = r2 })
+ = CS { cs_tm = p1+p2, cs_ty = q1+q2, cs_co = r1+r2 }
+
+zeroCS, oneTM :: CoreStats
+zeroCS = CS { cs_tm = 0, cs_ty = 0, cs_co = 0 }
+oneTM = zeroCS { cs_tm = 1 }
+
+sumCS :: (a -> CoreStats) -> [a] -> CoreStats
+sumCS f = foldr (plusCS . f) zeroCS
+
+coreBindsStats :: [CoreBind] -> CoreStats
+coreBindsStats = sumCS bindStats
+
+bindStats :: CoreBind -> CoreStats
+bindStats (NonRec v r) = bindingStats v r
+bindStats (Rec prs) = sumCS (\(v,r) -> bindingStats v r) prs
+
+bindingStats :: Var -> CoreExpr -> CoreStats
+bindingStats v r = bndrStats v `plusCS` exprStats r
+
+bndrStats :: Var -> CoreStats
+bndrStats v = oneTM `plusCS` tyStats (varType v)
+
+exprStats :: CoreExpr -> CoreStats
+exprStats (Var {}) = oneTM
+exprStats (Lit {}) = oneTM
+exprStats (App f (Type t))= tyCoStats (exprType f) t
+exprStats (App f a) = exprStats f `plusCS` exprStats a
+exprStats (Lam b e) = bndrStats b `plusCS` exprStats e
+exprStats (Let b e) = bindStats b `plusCS` exprStats e
+exprStats (Case e b _ as) = exprStats e `plusCS` bndrStats b `plusCS` sumCS altStats as
+exprStats (Cast e co) = coStats co `plusCS` exprStats e
+exprStats (Note _ e) = exprStats e
+exprStats (Type ty) = zeroCS { cs_ty = typeSize ty }
+ -- Ugh (might be a co)
+
+altStats :: CoreAlt -> CoreStats
+altStats (_, bs, r) = sumCS bndrStats bs `plusCS` exprStats r
+
+tyCoStats :: Type -> Type -> CoreStats
+tyCoStats fun_ty arg
+ = case splitForAllTy_maybe fun_ty of
+ Just (tv,_) | isCoVar tv -> coStats arg
+ _ -> tyStats arg
+
+tyStats :: Type -> CoreStats
+tyStats ty = zeroCS { cs_ty = typeSize ty }
+
+coStats :: Coercion -> CoreStats
+coStats co = zeroCS { cs_co = typeSize co }
+\end{code}