Return a list containing all of the mixins that are applied to the class being extended in order to derive the superclass of this class.
Note: Because the element model represents the state of the code, it is possible for it to be semantically invalid. In particular, it is not safe to assume that the inheritance structure of a class does not contain a cycle. Clients that traverse the inheritance structure must explicitly guard against infinite loops.
List<InterfaceType> get mixins;