in C#, this is legal: int i = new int(); whereas in Boo, i as int = int() ERROR: The type 'System.Int32' does not have a visible constructor that matches the argument list '()'. the blank constructor should create a new instance, even though it is impossible to define a blank constructor in a ValueType, it would be handy for instances like this: Length(Feet: 5.0) which would create a new Length, then assign Feet to 5.0, without having to go through an intermediary constructor.