First Draft: Static Single Assignment

[monkyyy]

On Sunday, 16 November 2025 at 02:43:03 UTC, Richard (Rikki) 
Andrew Cattermole wrote:
> Three things I'd like to see here:
>
> 1. Function parameters
>
> 2. Fields
>
> 3. Globals

```d
struct writeonce(T){
   final T data;
   final bool hasBeenSet;
   auto opAssign(T data_){
     assert( ! hasBeenSet);
     return data=data_;
}}
```

---

`void foo(ref final int a)` it would need to be ref to do anything