dip1000 and preview in combine to cause extra safety errors

[Timon Gehr]

On 09.06.22 03:10, Ali Çehreli wrote:
> On 6/8/22 18:04, Timon Gehr wrote:
>  > On 09.06.22 02:54, Timon Gehr wrote:
>  >> On 09.06.22 02:44, Ali Çehreli wrote:
>  >>> The society trusts C libraries, so do we.
>  >>
>  >> free(cast(void*)0xDEADBEEF)
>  >>
>  >> Seems legit.
>  >
>  > I guess this does not actually make the point very well. Second try:
>  >
>  > ```d
>  > free(new int);
>  > ```
>  >
>  > Seems legit. The C library can do no wrong!
> 
> I still don't get it. :(
> ...

`@trusted` has a specific meaning, it does not mean we believe the 
implementer of `free` is a nice guy. It means the specification of 
`free` says it's safe to call with any valid pointer and we believe that 
it is true. This is not the case, hence it cannot be `@trusted`.

> ...
> 
> I mean, who wins by @system-by-default? Nobody. The code is not safer.
> ...

That's on Walter.