Is there a way to prevent Weak::new() from over allocating?

Question

Follow-up of Why doesn't Weak::new() work when Rc::downgrade() does?

When attempting to implement Weak::new() in a way that would NOT require i

Answer 1

Yes, there is a way, and it was actually submitted to the standard library:

• Arc: remove unused allocation from Weak::new()
• Rc: remove unused allocation and fix segfault in Weak::new()

This change makes it so that Weak::new() allocates no memory at all. Instead, it is created with a null pointer. The only things done with a Weak are trying to upgrade, cloning, and dropping, meaning there are very few places that the code actually needs to check if the pointer is null.