@safe:

import std.stdio: writeln;

​

void f(ref int x, ref int[] arr) {

    x += 1;                  // this happens on arr[2]

    arr ~= new int[900000];  // array is relocated

    x += 1;                  // this now writes to random memory and will not be reflected on arr

}

​

void main() {

    auto arr = new int[10];

    f(arr[2], arr);

    writeln(arr[0..10]);

}