interface I {    void foo();}
class A : I {    void foo() { printf("A\n"); } }
class B : I {    void foo() { printf("B\n"); } }

class C(T) : T {
    void foo() {
        printf("C ");
        super.foo();
    }
}

class D(T) : T {
    void foo()
    {
        printf("D ");
        super.foo();
    }
}

alias C!(A) CA;
alias C!(B) CB;
alias C!(D!(A)) CDA;
alias D!(C!(B)) DCB;

alias C!(D!(C!(D!(B)))) CDCDB;

void main()
{
    I ca = new CA();
    I cb = new CB();
    ca.foo();
    cb.foo();

    I cda = new CDA();
    I dcb = new DCB();

    cda.foo();
    dcb.foo();

    I cdcdb = new CDCDB();
    cdcdb.foo();
}