Tracking Issue for Vec::push_mut #135974
Description
Feature gate: #![feature(push_mut)]
This is a tracking issue for Vec::push_mut and similar methods, as discussed in the comments of this ACP. This adds a way to get a reference to the just-pushed value, which can eliminate having to .unwrap() or access the back of the list twice.
Public API
// All are `#[must_use]` to suggest using `.push(...)` if you don't need the reference
impl<T> Vec<T> {
#[must_use]
pub fn push_mut(&mut self, value: T) -> &mut T;
#[must_use]
pub fn insert_mut(&mut self, index: usize, element: T) -> &mut T;
}
impl<T> VecDeque<T> {
#[must_use]
pub fn push_front_mut(&mut self, value: T) -> &mut T;
#[must_use]
pub fn push_back_mut(&mut self, value: T) -> &mut T;
#[must_use]
pub fn insert_mut(&mut self, index: usize, value: T) -> &mut T;
}
impl<T> LinkedList<T> {
#[must_use]
pub fn push_front_mut(&mut self, elt: T) -> &mut T;
#[must_use]
pub fn push_back_mut(&mut self, elt: T) -> &mut T
}Steps / History
- Implementation: Implement
push_mut#135975 - Final comment period (FCP)
- Stabilization PR
Unresolved Questions
Doesmust_usemake sense? Are there downsides ofpush_mutvs.push?