Added support for using a temporary to implement emulated ABI return from inline asm, could be easier to use, but I think this will do. It's so extremely target dependent in any case that doing a completely generic approach seems hard.

module arrays4;

void main()
{
    int[] arr;
    arr ~= 3;
    assert(arr.length == 1);
    assert(arr[0] == 3);
    arr ~= 5;
    assert(arr.length == 2);
    assert(arr[0] == 3);
    assert(arr[1] == 5);
}