On Wed, Mar 31, 2010 at 12:57 PM, Bas van Dijk <v.dijk.bas at gmail.com> wrote: > main = let !t = genterm in defaultMain [bench "subst" $ nf (subst u) t] Oops, that should be: main = let t = genterm in rnf t `seq` defaultMain [bench "subst" $ nf (subst u) t] Bas