Code shared from run.dlang.io.

main.d

import std,std.format,std.container,std.range;
//shared
class Baz { int v; this(int w) { this.v = w; }
    //const bool opEquals(const Baz o) pure nothrow @safe { return this.v == o.v; }
    override string toString() const pure nothrow @safe { return this.v.to!string; }
    //string toString() shared const pure nothrow @safe { return this.v.to!string; }
}
//bool opEquals(Baz t,Baz o) pure nothrow { return t.v == o.v; }
void main() { //writeln("Hello D");
    DList!Baz q;
    Baz b1 = new Baz(123),b2 = new Baz(456);
    q.insertFront(b1); q.insertFront(b2);
    //foreach (e; q) writeln(e);
    q.removeFront;
    //foreach (e; q) writeln(e);
    //writefln("%s",q);
}