Andrei Alexandrescu , dans le message (digitalmars.D:172280), a écrit : >> For Fruit.Seed it's Fruit, for AppleSeed it's Apple. This makes sense >> because the Apple, which AppleSeed sees is the same object, which >> Fruit.Seed sees as it's base type Fruit. > > That would mean AppleSeed has two outer fields: a Fruit and an Apple.
Only one. Apple. And when AppleSeed.super seed this Apple, it sees a fruit. AppleSeed a; assert(is(typeof(a.outer) == Apple)); assert(is(typeof(a.super) == Seed)); assert(is(typeof(a.super.outer) == Fruit)); //but: assert(a.outer is a.super.outer); If you can't figure out how can a.outer and a.super.outer have two different types, but be the same, think about covariant return.
