Metaprogramming with traits

[Ram_B via Digitalmars-d-learn]

How i can get fields of derived classes in runtime? This not works

import std.traits;
import std.experimental.logger;


class A {
	int a,b;
	this(){}
	void fields(){
		log(FieldNameTuple!this);	
	}
}

class B : A{
	int c;
	this(){}
}

void main(){
	B b = new B();
	b.fields();
}