Direction for @safe/-dip1000

[Florian Weimer]

On Sunday, 13 February 2022 at 12:26:52 UTC, ag0aep6g wrote:
> On 13.02.22 12:15, Florian Weimer wrote:
>> I've tried to figure out where this is heading. Is the 
>> eventual goal (irrespective of mechanism) that sticking 
>> `@safe` onto the `main` function will ensure memory safety for 
>> the whole program?
>
> Roughly, that's what @safe is supposed to be, yes. But it's not 
> quite as simple because `main` isn't the only possible entry 
> point, and because @trusted exists.

Right, but it's still a big step forward.

> Since you mentioned it in the topic, note that DIP 1000 doesn't 
> make @safe safer. It allows some formerly @system code to 
> become @safe. If you write that kind of code, DIP 1000 is nice 
> to have. If you don't, DIP 1000 doesn't affect you.

Hmm.  This compiles without `-dip1000` (or 
`-ftransition=dip1000`), but is unsafe:

```d
int[] global;

@safe
void f0(int[] val) {
     global = val;
}

@safe
void f1() {
   int[3] local = [1, 2, 3];
   f0(local);
}

```

It's rejected in DIP 1000 mode (both by DMD and GDC).