pub struct OccupiedError<'a, K, V, S, A: Allocator = Global> {
    pub entry: OccupiedEntry<'a, K, V, S, A>,
    pub value: V,
}
Expand description

The error returned by try_insert when the key already exists.

Contains the occupied entry, and the value that was not inserted.

Examples

use hashbrown::hash_map::{HashMap, OccupiedError};

let mut map: HashMap<_, _> = [("a", 10), ("b", 20)].into();

// try_insert method returns mutable reference to the value if keys are vacant,
// but if the map did have key present, nothing is updated, and the provided
// value is returned inside `Err(_)` variant
match map.try_insert("a", 100) {
    Err(OccupiedError { mut entry, value }) => {
        assert_eq!(entry.key(), &"a");
        assert_eq!(value, 100);
        assert_eq!(entry.insert(100), 10)
    }
    _ => unreachable!(),
}
assert_eq!(map[&"a"], 100);

Fields

entry: OccupiedEntry<'a, K, V, S, A>

The entry in the map that was already occupied.

value: V

The value which was not inserted, because the entry was already occupied.

Trait Implementations

Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.