Tracking Issue for linked_list_retain

[TennyZhuang]

Feature gate: #![feature(linked_list_retain)]

This is a tracking issue for LinkedList::{retain, retain_mut}

Public API

// alloc::collections

pub struct LinkedList;

impl LinkedList {
    pub fn retain_mut<F>(&mut self, mut f: F)
    where
        F: FnMut(&mut T) -> bool;

    pub fn retain<F>(&mut self, mut f: F)
    where
        F: FnMut(&T) -> bool;
}

Steps / History

• Implementation: add LinkedList::{retain,retain_mut} #114136
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• None yet.

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

[TennyZhuang]

@rustbot claim

[finnbear]

As far as I know, {Vec, VecDeque}::retain(&mut self, fn(&T) -> bool) use an immutable reference for backwards compatibility, and retain_mut was a workaround. See #90829 and #39560 (comment) (there are no {Hash, BTree}Map::retain_mut and {Hash, BTree}Map::retain provide mutable references).

Are you adding LinkedList::{retain, retain_mut} for consistency/code clarity or could they be merged into retain with mutable references?

[TennyZhuang]

As far as I know, {Vec, VecDeque}::retain(&mut self, fn(&T) -> bool) use an immutable reference for backwards compatibility, and retain_mut was a workaround

Sorry, I just found out about this.

could they be merged into retain with mutable references?

If consistency between collections has already been broken by {Hash, BTree}Map, I can just merge them to a single retain.