(ARM, §8.2.6) The compiler does not bind default arguments in a member function at the end of the class declaration. Before the default argument appears, you must declare any value that you use in the default argument expression. For example:

class foo {
  enum A { AA };
  int f(A a = AA); // OK
  int f(B b = BB); // ERROR: BB is not declared yet
  enum B { BB };
};