Proper way to accept either static or dynamic array as a parameter

[jfondren]

On Sunday, 12 September 2021 at 02:44:36 UTC, Alex Bryan wrote:
> `T[] dynArr` can be passed (by reference) to a function that 
> takes `ref T[] data` but `T[10] data` cannot? Why not?

```d
void add1(ref int[] nums) {
     nums ~= 1;
}

unittest {
     int[] nums;
     nums.add1;
     nums.add1;
     nums.add1;
     assert(nums == [1, 1, 1]);
}
```

the `ref` allows `add1` to extend the length of the slice passed 
to it, with potential reallocation. This doesn't make sense with 
a static array whose length can't be modified.