(* The inheritance analysis has 2 stages, graph construction & cyclic checking.
    it will abort if duplicate or undefined class definitions are found before do cyclic checking *)
-- uncomment the lines below to get convinced that 1st stage works
(*
class DupDef {};

class DupDef {};

class DupDef1 {};

class DupDef1 {};

class A inherits SCHEISSE{}; 
*)
(*
class D inherits D {};

class Cycle1 inherits Cycle2 {};
class Cycle2 inherits Cycle3 {};
class Cycle3 inherits Cycle1 {};

class Cycle4 inherits Cycle3 {};
*)
class Ok1{};
class Ok2_1 inherits Ok1 {};
class Ok2_2 inherits Ok1 {};
class Ok3 inherits Ok2_1 {};
class Ok4 inherits Ok2_2 {};

(* Cool has restrictions on inheriting from basic classes *)

(*class Err1 inherits Int {};
class Err3 inherits String {};
class Err3 inherits Bool {};
class Err4 inherits Err3 {};*)
class Err4 inherits Ok1 {
    bye: SS <- 10;
    hello(a: TT) : NOEXIST { new Object };
};


class Main inherits IO {
    main(): Object {
        {
            (new Err4).hell();
        }
    };
};