struct S

{

  int[] i;

​

  ref opIndex(size_t index) => i[index];

​

  void opIndexAssign(int value) { i[] = value; }

  void opIndexAssign(int value, size_t idx) { i[idx] = value; }

}

​

void main()

{

  auto s = S([1, 2]);

​

  s[] = 2;

  assert(s.i == [2, 2]);

​

  s[1] = 42;

  assert(s.i == [2, 42]);

​

  s[0]++;

  assert(s.i == [3, 42]);

  s[0] += 1;

  assert(s.i == [4, 42]);

}