1.0.0[][src]Trait core::convert::AsMut

pub trait AsMut<T: ?Sized> {
    fn as_mut(&mut self) -> &mut T;

Used to do a cheap mutable-to-mutable reference conversion.

This trait is similar to AsRef but used for converting between mutable references. If you need to do a costly conversion it is better to implement From with type &mut T or write a custom function.

Note: This trait must not fail. If the conversion can fail, use a dedicated method which returns an Option<T> or a Result<T, E>.

Generic Implementations


Using AsMut as trait bound for a generic function we can accept all mutable references that can be converted to type &mut T. Because Box<T> implements AsMut<T> we can write a function add_one that takes all arguments that can be converted to &mut u64. Because Box<T> implements AsMut<T>, add_one accepts arguments of type &mut Box<u64> as well:

fn add_one<T: AsMut<u64>>(num: &mut T) {
    *num.as_mut() += 1;

let mut boxed_num = Box::new(0);
add_one(&mut boxed_num);
assert_eq!(*boxed_num, 1);

Required methods

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

Performs the conversion.

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impl<T> AsMut<[T]> for [T][src]

impl<T, const N: usize> AsMut<[T]> for [T; N][src]

impl<T: ?Sized, U: ?Sized, '_> AsMut<U> for &'_ mut T where
    T: AsMut<U>, 

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