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);

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§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§

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impl<K: Debug, V: Debug, S, A: Allocator> Debug for OccupiedError<'_, K, V, S, A>

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

Formats the value using the given formatter. Read more
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impl<'a, K: Debug, V: Debug, S, A: Allocator> Display for OccupiedError<'a, K, V, S, A>

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl<'a, K, V, S, A> RefUnwindSafe for OccupiedError<'a, K, V, S, A>where A: RefUnwindSafe, K: RefUnwindSafe, S: RefUnwindSafe, V: RefUnwindSafe,

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impl<'a, K, V, S, A> Send for OccupiedError<'a, K, V, S, A>where A: Send, K: Send, S: Send, V: Send,

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impl<'a, K, V, S, A> Sync for OccupiedError<'a, K, V, S, A>where A: Sync, K: Sync, S: Sync, V: Sync,

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impl<'a, K, V, S, A> Unpin for OccupiedError<'a, K, V, S, A>where K: Unpin, V: Unpin,

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impl<'a, K, V, S, A = Global> !UnwindSafe for OccupiedError<'a, K, V, S, A>

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> ToString for Twhere T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.