class B<X, Y> {}

class C1<X extends X Function(Y), Y extends X Function(Y)> {}

C1 c1;

class C2<X extends X Function(Y), Y extends Y Function(X)> {}

C2 c2;

class C3<X extends X Function(X, Y), Y extends X Function(X, Y)> {}

C3 c3;

class C4<X extends X Function(X, Y), Y extends Y Function(X, Y)> {}

C4 c4;

class D1<X extends B<X, Y>, Y extends X Function(Y)> {}

D1 d1;

class D2<X extends B<X, Y>, Y extends Y Function(X)> {}

D2 d2;

class D3<X extends B<X, Y>, Y extends X Function(X, Y)> {}

D3 d3;

class D4<X extends B<X, Y>, Y extends Y Function(X, Y)> {}

D4 d4;

class E<X extends X Function(X)> {}

E e;
main() {}