D not considered memory safe

[Walter Bright]

On 7/3/2024 6:52 PM, Steven Schveighoffer wrote:
> ```d
> ref int bar(ref int x) => x;
> 
> ref int foo()
> {
>     int i = 0;
>     return bar(i);
> }
> ```
> 
> Compiles, even with dip1000.

```
@safe:  // <=== I added this line

ref int bar(ref int x) => x;

ref int foo()
{
     int i = 0;
     return bar(i);
}
```

fails with:

```
test.d(3): Error: returning `x` escapes a reference to parameter `x`
test.d(3):        perhaps annotate the parameter with `return`
```

when compiled with -preview=dip1000