At 2001-01-16 13:18, Magnus Carlsson wrote: >f1 = Just 3 >f2 = f3 = f4 = Nothing So I've declared b = d, but 'theValue b' and 'theValue d' are different because theValue is looking at the static type of its argument? What's to stop 'instance TheValue Base' applying in 'theValue d'? -- Ashley Yakeley, Seattle WA