Any reason Ref can't just be one reference?

[jgarvin]

pub struct Ref<'a, T: 'a> {
    borrow_count: &'a Cell<isize>,
    value: &'a T,
}

AFAICT these two references always point to adjacent data:

struct RefManagerInnerData<T> {
    borrow_count: Cell<isize>,
    value: T,
}

Is there any reason to not prefer:

pub struct Ref<'a, T: 'a> {
    inner: &'a RefManagerInnerData<T>,
}

One issue I see is the mutable case:

#[derive(Debug)]
pub struct RefMut<'a, T: 'a> {
    borrow_count: &'a Cell<isize>,
    value: &'a mut T,
}

Because here one of the references is immutable and the other is mutable. However AFAICT we could just use a pointer instead, and present the same safe interface.

[tuxzz]

Hi jgarvin,

We can't use &'a RefManagerInnerData<T>/&mut 'a RefManagerInnerData<T>. If a RefMut exists and we called some function like RefManager::borrow(), it violates the strict aliasing rule because RefManager::borrow requires a immutable reference of RefManagerInnerData::borrow_count.

We are afraid of using *const RefManagerInnerData<T>/*mut RefManagerInnerData<T> would also violate strict aliasing rule because we didn't remember the rust nomicon say these in 2018:

... we don't actually care if aliasing occurs if there aren't any actual writes to memory happening ...