Struct VacantEntry

pub struct VacantEntry<'a, T, S, A: Allocator = Global> { pub(in ::collections::hash::set) base: VacantEntry<'a, T, S, A> }

A view into a vacant entry in a HashSet. It is part of the Entry enum.

Examples

#![feature(hash_set_entry)]

use std::collections::hash_set::{Entry, HashSet};

let mut set = HashSet::<&str>::new();

let entry_v = match set.entry("a") {
    Entry::Vacant(view) => view,
    Entry::Occupied(_) => unreachable!(),
};
entry_v.insert();
assert!(set.contains("a") && set.len() == 1);

// Nonexistent key (insert)
match set.entry("b") {
    Entry::Vacant(view) => view.insert(),
    Entry::Occupied(_) => unreachable!(),
}
assert!(set.contains("b") && set.len() == 2);

Fields

base: VacantEntry<'a, T, S, A>

Implementations

impl<'a, T, S, A: Allocator> VacantEntry<'a, T, S, A>

fn get(&self) -> &T

Gets a reference to the value that would be used when inserting through the VacantEntry.

Examples

#![feature(hash_set_entry)]

use std::collections::HashSet;

let mut set = HashSet::new();
assert_eq!(set.entry("poneyland").get(), &"poneyland");

fn into_value(self) -> T

Take ownership of the value.

Examples

#![feature(hash_set_entry)]

use std::collections::hash_set::{Entry, HashSet};

let mut set = HashSet::new();

match set.entry("poneyland") {
    Entry::Occupied(_) => panic!(),
    Entry::Vacant(v) => assert_eq!(v.into_value(), "poneyland"),
}

fn insert(self)
where
    T: Hash,
    S: BuildHasher,

Sets the value of the entry with the VacantEntry's value.

Examples

#![feature(hash_set_entry)]

use std::collections::HashSet;
use std::collections::hash_set::Entry;

let mut set = HashSet::new();

if let Entry::Vacant(o) = set.entry("poneyland") {
    o.insert();
}
assert!(set.contains("poneyland"));

fn insert_entry(self) -> OccupiedEntry<'a, T, S, A>
where
    T: Hash,
    S: BuildHasher,

Trait Implementations

impl<T: Debug, S, A: Allocator> Debug for VacantEntry<'_, T, S, A>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Auto Trait Implementations

impl<'a, T, S, A = Global> !UnwindSafe for VacantEntry<'a, T, S, A>

impl<'a, T, S, A> Freeze for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: Freeze,

impl<'a, T, S, A> RefUnwindSafe for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: RefUnwindSafe,

impl<'a, T, S, A> Send for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: Send,

impl<'a, T, S, A> Sync for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: Sync,

impl<'a, T, S, A> Unpin for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: Unpin,

impl<'a, T, S, A> UnsafeUnpin for VacantEntry<'a, T, S, A> where VacantEntry<'a, T, S, A>: UnsafeUnpin,

Blanket Implementations

impl<T> Any for VacantEntry<'a, T, S, A> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for VacantEntry<'a, T, S, A> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for VacantEntry<'a, T, S, A> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for VacantEntry<'a, T, S, A>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for VacantEntry<'a, T, S, A> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for VacantEntry<'a, T, S, A>

impl<T, U> Into<U> for VacantEntry<'a, T, S, A> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for VacantEntry<'a, T, S, A> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for VacantEntry<'a, T, S, A> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>