I think I've found a small bug:
@startuml
hide empty members
A_Driver -> A_Car : drives >
(A_Driver, A_Car) -> A_Contract : under Contract >
B_Driver -> B_Car : drives >
(B_Car, B_Driver) -> B_Contract : under Contract >
@enduml
Variant A:
small arrow on Label from association class is not drawn
Variant B:
Direction of Relation Arrow and Label Arrow is reversed, if the Association class is defined in reversed order (Car, Driver) instead of (Driver, Car)
thanks for the great work,
Michael