HashMap keyed by Rc<RefCell<..>>

[anon80458984]

@worik

It makes no difference to me.

If you are willing to hash by ADDRESS of Rc, rather than the value inside the RefCell, you can use the same technique as:

Hash based on address (not value) of Rc

I genuinely want to hash based on the address, not the value of a Rc. This is what I have so far: #[derive(Clone)] pub struct MathStringPtr(Rc<MathStringBase>); impl Hash for MathStringPtr { fn hash<H: Hasher>(&self, state: &mut H) { let rc = &self.0; let ptr = Rc::into_raw(rc.clone()); state.write_usize(ptr as usize); unsafe { let _ = Rc::from_raw(ptr); }; } } Does this look correct? Is there an idiomatic way to do this?

Instead of using Rc<RefCell> do

pub struct MyWrapper(Rc<RefCell<T>>);

then, using Hash based on address (not value) of Rc you can have "hashing on MyWrapper == hashing on address the Rc points to"