shared - i need it to be useful

[aliak]

On Saturday, 20 October 2018 at 09:04:17 UTC, Walter Bright wrote:
> Somehow, you still have to find a way to give the shared path 
> access, through a gate or a cast or a lock or whatever. And 
> then it breaks, because two different threads are accessing the 
> same data each thinking that data is not shared.

When you say that, then under Manu's proposal and the code below:

class C {
   void f();
   void g() shared;
}

void t1(shared C c) {
   c.g; // ok
   c.f; // error
}

void t2(shared C c) {
   c.g; // ok
   c.f; // error
}

auto c = new C();
spawn(&t1, c);
spawn(&t2, c);
c.f; // ok
c.g; // ok

Do you mean the implementation of C.g? Since that is shared 
wouldn't that just be a normal understanding that you'd need to 
synchronize the data access in shared since it's a shared method? 
And if you mean C.f, then if that accessed data (that was 
accessed by C.g) unsafely, then that's just a bad implementation 
no? Or?

Cheers,
- Ali