Tracking issue for RFC 1789: Conversions from `&mut T` to `&Cell<T>`

[aturon]

This is a tracking issue for the RFC "Conversions from &mut T to &Cell<T>" (rust-lang/rfcs#1789).

Steps:

• Implement the RFC
• Adjust documentation (see instructions on forge)
• Stabilization PR (see instructions on forge)

[bstrie]

This appears to have been implemented and is sitting behind the as_ref feature flag. Would anyone like to make any motions toward stabilization, or did the long discussion in the implementation PR cast doubts on the design?

[SimonSapin]

Let’s.

@rfcbot fcp merge

[rfcbot]

Team member @SimonSapin has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @Kimundi
• @KodrAus
• @SimonSapin
• @alexcrichton
• @aturon
• @dtolnay
• @sfackler
• @withoutboats

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[dtolnay]

As I understand it, the new API here currently consists of:

impl<T: ?Sized> Cell<T> {
    pub fn from_mut(t: &mut T) -> &Cell<T>;
}

impl<T> Cell<[T]> {
    pub fn as_slice_of_cells(&self) -> &[Cell<T>];
}