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
}
What's the difference between that and this:
void fun() {
T[] ta = [T()].dup;
T* t = ta[0];
delete ta; // or however you do it
*t = ...;
}
Why is this a parameter passing issue and not a "you kept a
sub-reference to a deleted chunk" issue?
