import std.stdio;

​

class SharedArray(T) {

  public T[] array;

  alias array this;  // subtyping

​

   final @disable:

   T front();

   void popFront();

   bool empty();

}

​

alias Filenames = SharedArray!(string);

​

struct S {

  Filenames fns;

  void alloc() {

    fns = new Filenames();

  }

}

​

void main(string[] args) {

  S s0;

  s0.alloc();

  s0.fns ~= "abc";

​

  foreach (i; 0..3) {

    S* s1 = new S();

    *s1 = s0;   //  copy the value from s0 to *s1

    writeln(s0.fns);

  }

}