class Class<T> {}

class ConcreteClass implements Class<ConcreteClass> {}

typedef F<X extends Class<X>> = X;

class G<X extends Class<X>> {}

F? field1a, field1b;
F<dynamic>? field2a, field2b;
F<Class>? field3a, field3b;
F<Class<dynamic>>? field4a, field4b;
F<ConcreteClass>? field5a, field5b;
F<Class<ConcreteClass>>? field6a, field6b;
F<Object>? field7a, field7b;
F<int>? field8a, field8b;
G? field1c, field1d;
G<dynamic>? field2c, field2d;
G<Class>? field3c, field3d;
G<Class<dynamic>>? field4c, field4d;
G<ConcreteClass>? field5c, field5d;
G<Class<ConcreteClass>>? field6c, field6d;
G<Object>? field7c, field8d;
G<int>? field8c, field7d;

class Class1 {
  F? field1a, field1b;
  F<dynamic>? field2a, field2b;
  F<Class>? field3a, field3b;
  F<Class<dynamic>>? field4a, field4b;
  F<ConcreteClass>? field5a, field5b;
  F<Class<ConcreteClass>>? field6a, field6b;
  F<Object>? field7a, field7b;
  F<int>? field8a, field8b;
  G? field1c, field1d;
  G<dynamic>? field2c, field2d;
  G<Class>? field3c, field3d;
  G<Class<dynamic>>? field4c, field4d;
  G<ConcreteClass>? field5c, field5d;
  G<Class<ConcreteClass>>? field6c, field6d;
  G<Object>? field7c, field8d;
  G<int>? field8c, field7d;
}

extension Extension1 on int {
  static F? field1a, field1b;
  static F<dynamic>? field2a, field2b;
  static F<Class>? field3a, field3b;
  static F<Class<dynamic>>? field4a, field4b;
  static F<ConcreteClass>? field5a, field5b;
  static F<Class<ConcreteClass>>? field6a, field6b;
  static F<Object>? field7a, field7b;
  static F<int>? field8a, field8b;
  static G? field1c, field1d;
  static G<dynamic>? field2c, field2d;
  static G<Class>? field3c, field3d;
  static G<Class<dynamic>>? field4c, field4d;
  static G<ConcreteClass>? field5c, field5d;
  static G<Class<ConcreteClass>>? field6c, field6d;
  static G<Object>? field7c, field8d;
  static G<int>? field8c, field7d;
}

main() {}