Trait core::convert::AsRef1.0.0 [−] [src]

pub trait AsRef<T: ?Sized> {
    fn as_ref(&self) -> &T;
}

A cheap, reference-to-reference conversion.

AsRef is very similar to, but different than, Borrow. See the book for more.

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>.

Examples

Both String and &str implement AsRef<str>:

fn main() { fn is_hello<T: AsRef<str>>(s: T) { assert_eq!("hello", s.as_ref()); } let s = "hello"; is_hello(s); let s = "hello".to_string(); is_hello(s); }
fn is_hello<T: AsRef<str>>(s: T) {
   assert_eq!("hello", s.as_ref());
}

let s = "hello";
is_hello(s);

let s = "hello".to_string();
is_hello(s);

Generic Impls

  • AsRef auto-dereference if the inner type is a reference or a mutable reference (eg: foo.as_ref() will work the same if foo has type &mut Foo or &&mut Foo)

Required Methods

fn as_ref(&self) -> &T

Performs the conversion.

Implementors