On 11/02/2016 07:29 AM, Nick Treleaven wrote:
On Wednesday, 2 November 2016 at 05:00:23 UTC, Andrei Alexandrescu wrote:
In order to make opAssign safe, a language change will be necessary.
Technically, it should be possible with runtime checks:
https://forum.dlang.org/post/[email protected]
The checking overheads disappear when -noboundschecks is passed. The
user has to manually copy the RCSlice when necessary for correct code.
It seems opAssign for RCSlice is unsafe, is that right? Consider (with
your codebase):
@safe void fun(ref RCSlice!int a, ref RCSlice!int b)
{
a = RCSlice!int();
... use b ...
}
@safe void gun(ref RCSlice!int s)
{
fun(s, s);
}
Assume the reference count of s is 1 upon entering gun. Then the first
thing opAssign does is to call the destructor of the slice, which
deallocates memory. Subsequently the other reference (b) is dangling.
Andrei
