Why this doesn't produce an error or works as expected?

[partypooper]

On Friday, 4 July 2025 at 18:04:55 UTC, partypooper wrote:
> It doesn't work. Or it works even worse: changing _pos, but not 
> _dest. What is going on is that on `+=` it for some reason 
> invokes "getter", not "setter". I specifically omitted "ref", 
> because I already have known of that behavior.

In other words you through reference of the "getter" which 
returns "_pos" setting it to the right part of the "+=". Which in 
ideal world should error too.

You can get what i'm want is to duplicating
```d
_dest.x = _pos.x
_dest.y = _pos.y
``` In a getter, but it is definitely not sound right.