More radical ideas about gc and reference counting

[Tommi via Digitalmars-d]

On Monday, 12 May 2014 at 00:50:24 UTC, Walter Bright wrote:
> On 5/11/2014 1:59 PM, Timon Gehr wrote:
>> Borrowed pointers are not even superficially similar to near*. 
>> They are
>> compatible with everything else, because they can store data 
>> that was borrowed
>> from anywhere else.
>
> As long as those pointers don't escape. Am I right in that one 
> cannot store a borrowed pointer into a global data structure?

Perhaps:

struct Test {
     n: &'static int, // [1]
     m: int
}

static val: int = 123;
static mut t: Test = Test { n: &'static val, m: 0 };

fn main() {
     unsafe { // [2]
         let p = &mut t.m;
         *p = 456;
         println!("{} {}", *t.n, t.m); // prints: 123 456
     }
}

[1]: In order to create a static instance of 'Test', the 'n' 
field (which is a borrowed pointer) must be specified as to be 
pointing at a static immutable (int) variable.

[2]: Any use of static mutable data requires the use of an 
'unsafe' block (similar to @trusted in D)