alpheccar wrote: > Can someone confirm me that: > > type TA = A :+: B > type TB = C :+: D > type T = TA :+: TB This is type T = (A :+: B) :+: (C :+: D) > is not equivalent to > > type T = A :+: B :+: C :+: D is type T = A :+: (B :+: (C :+: D)) So these types are indeed not the same. Twan