interface Intf {
  in void evt();
  behaviour {
    void f() {
      bool b = false;
      if (b) {
        f();
        b = true;
      }    
    }

    on evt: {}
  }
}

interface Intf2 {
  in void evt();
  behaviour {
    bool f() {
      bool b = g();
      return b;
    }
    bool g() {
      bool b = f();
      return b;
    }
    
    on evt: {}
  }
}

interface Intf3 {
  in void evt();
  behaviour {
    void f() {
      f();
    }
    void g() {
      f();
      g();
    }
    
    on evt: {}
  }
}