Tracking issue for weak_ptr_eq

[Thomasdezeeuw]

This is a tracking issue for rc::Weak::ptr_eq and sync::Weak::ptr_eq.

Feature gate: #![feature(weak_ptr_eq)].

Steps:

• Implement the RFC (Add Weak.ptr_eq #55987).
• Stabilization PR.

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Old issue:

Rc has a function called ptr_eq it compares if the Rc points to the value, not the values themselves. I would like to add the same function to Weak. I got an implementation but have two questions:

• Does this require an RFC? Or is this small enough to do without one.
• What to do with dangling pointer, e.g. created by Weak::new(). I would argue always return false if either one is dangling.

[jethrogb]

This is a small API introduction, it doesn't require an RFC. You can just file a PR.

[F001]

I have a question that why Weak didn't have strong_count and weak_count methods either.
I think these methods are also useful.

// when inner ptr is dangling, returns None.
pub fn weak_count(this: &Weak<T>) -> Option<usize>

[Thomasdezeeuw]

@F001 I agree, you could create a PR and then someone from the libs team will comment (atleast that is what I did).

[Thomasdezeeuw]

I've updated the first comment to turn the issue into a tracking issue.

[vorner]

Hello. This looks potentially useful. How long does a feature this small need to sit around before it's considered for stabilization? (if I'm not missing something, there's no issue raised with this currently)

[Thomasdezeeuw]

If the team agrees I can make a stabilisation pr for 1.35/1.36.