In C#4.0, apparently you can declare JOption as interface NOption<out T> { ... } such that NOption<Mysub> is a subtype of NOption<Mysuper>. Still messy to

In C#4.0, apparently you can declare JOption as interface NOption<out T> { ... } such that NOption<Mysub> is a subtype of NOption<Mysuper>. Still messy to read, though, and C# has ?-types anyway.