opDispatch doesn't play nice with inheritance

[Carl Sturtivant]

//Consider this:
import std.stdio;

void main() {
     X obj = new Y;
     writeln( obj._f() );
}

class Proxy {
     X x;
     this(X x) { this.x = x; }
     string _f() { return "Proxy._f called"; }
}

class X {
     auto opDispatch(string f, Args...)(Args args) {
         Proxy p = new Proxy(this);
         return mixin("p."~f~"(args)");
     }
}

class Y : X {
     string _f() { return "Y._f called"; }
}
//

Presumably the presence of obj._f()in main causes the compilation 
of a function _f() in the class X, yet the function _f() in Y 
that inherits it merely shadows it; the keyword override cannot 
be used for this function.

opDispatch is special in that it allows for functions to be added 
to a class or struct when undefined overtly but used elsewhere 
but it seems those functions sadly are final.

Can anything useful be done to remedy the situation?