On Thursday, 18 February 2016 at 18:41:58 UTC, H. S. Teoh wrote:
On Thu, Feb 18, 2016 at 07:30:34PM +0100, Timon Gehr via
Digitalmars-d wrote:
No problem here. There is no way to assign to a void[] without
doing 2.
Sure there is:
void breakSafety(void[] data) @safe
{
union U {
void[] d;
int[] arr;
}
U u;
u.d = data;
u.arr[0] = 0xFF; // kaboom
}
Well, unions with an array in them can't be @safe. That's clearly
a bug, regardless of whether void[] is involved or not.
Regardless, as far as I can tell, there is zero @safety problem
with converting to void[]. You'll never get corrupted memory with
that conversion. It's converting back that risks screwing
everything up. And that's what can't be @safe.
It's only one of many culprits. As long as there is any way
around @safe, the entire system of guarantees breaks down.
Of course, and we went about things the wrong way with @safe. It
should have been done via whitelisting, whereas we've done it via
blacklisting. Given that fact, we're pretty much permanently at
risk of @safe being broken.
- Jonathan M Davis
