Type representing the absence of an entry, as returned by HashTable::find_entry and HashTable::get_bucket_entry.

This type only exists due to limitations in Rust's NLL borrow checker. In the future, those methods will return an Option<OccupiedEntry> and this type will be removed.

Examples

# #[cfg(feature = "nightly")]
# fn test() {
use hashbrown::hash_table::{AbsentEntry, Entry};
use hashbrown::{HashTable, DefaultHashBuilder};
use std::hash::BuildHasher;

let mut table: HashTable<&str> = HashTable::new();
let hasher = DefaultHashBuilder::default();
let hasher = |val: &_| hasher.hash_one(val);

let entry_v: AbsentEntry<_, _> = table.find_entry(hasher(&"a"), |&x| x == "a").unwrap_err();
entry_v
    .into_table()
    .insert_unique(hasher(&"a"), "a", hasher);
assert!(table.find(hasher(&"a"), |&x| x == "a").is_some() && table.len() == 1);

// Nonexistent key (insert)
match table.entry(hasher(&"b"), |&x| x == "b", hasher) {
    Entry::Vacant(view) => {
        view.insert("b");
    }
    Entry::Occupied(_) => unreachable!(),
}
assert!(table.find(hasher(&"b"), |&x| x == "b").is_some() && table.len() == 2);
# }
# fn main() {
#     #[cfg(feature = "nightly")]
#     test()
# }