Re: RCArray is unsafe

[Zach the Mystic via Digitalmars-d]

On Sunday, 1 March 2015 at 20:51:35 UTC, Michel Fortin wrote:

On 2015-03-01 19:21:57 +0000, Walter Bright said:

The trouble seems to happen when there are two references to the same object passed to a function. I.e. there can be only one "borrowed" ref at a time.

I'm thinking this could be statically disallowed in @safe code.

That's actually not enough. You'll have to block access to global variables too:

        S s;

        void main() {
                s.array = RCArray!T([T()]);   // s.array's refcount is now 1
                foo(s.array[0]);           // pass by ref
        }
        void foo(ref T t) {
                s.array = RCArray!T([]);      // drop the old s.array
                t.doSomething();              // oops, t is gone
        }

Globals to impures, that is.