Trait std::convert::AsRef

pub trait AsRef<T> where 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 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-dereferences if the inner type is a reference or a mutable reference (e.g.: 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

• impl<T> AsRef<T> for Box<T> where T: ?Sized
• impl<T> AsRef<T> for Arc<T> where T: ?Sized
• impl<T> AsRef<T> for Rc<T> where T: ?Sized
• impl<'a, T, U> AsRef<U> for &'a T where T: AsRef<U> + ?Sized, U: ?Sized
• impl<'a, T, U> AsRef<U> for &'a mut T where T: AsRef<U> + ?Sized, U: ?Sized
• impl<T> AsRef<[T]> for [T]
• impl AsRef<str> for str
• impl<'a, T> AsRef<[T]> for std::slice::Iter<'a, T>
• impl AsRef<[u8]> for str
• impl<T> AsRef<[T]> for [T; 0]
• impl<T> AsRef<[T]> for [T; 1]
• impl<T> AsRef<[T]> for [T; 2]
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• impl<T> AsRef<[T]> for [T; 17]
• impl<T> AsRef<[T]> for [T; 18]
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• impl<T> AsRef<[T]> for [T; 30]
• impl<T> AsRef<[T]> for [T; 31]
• impl<T> AsRef<[T]> for [T; 32]
• impl<'a, T> AsRef<T> for std::borrow::Cow<'a, T> where T: ToOwned + ?Sized
• impl AsRef<str> for std::string::String
• impl AsRef<[u8]> for std::string::String
• impl<T> AsRef<Vec<T>> for std::vec::Vec<T>
• impl<T> AsRef<[T]> for std::vec::Vec<T>
• impl AsRef<CStr> for CStr
• impl AsRef<CStr> for CString
• impl AsRef<OsStr> for std::ffi::OsStr
• impl AsRef<OsStr> for std::ffi::OsString
• impl AsRef<OsStr> for str
• impl AsRef<OsStr> for std::string::String
• impl<'a> AsRef<OsStr> for Component<'a>
• impl<'a> AsRef<Path> for std::path::Components<'a>
• impl<'a> AsRef<OsStr> for std::path::Components<'a>
• impl<'a> AsRef<Path> for std::path::Iter<'a>
• impl<'a> AsRef<OsStr> for std::path::Iter<'a>
• impl AsRef<OsStr> for std::path::PathBuf
• impl AsRef<OsStr> for std::path::Path
• impl AsRef<Path> for std::path::Path
• impl AsRef<Path> for std::ffi::OsStr
• impl<'a> AsRef<Path> for std::borrow::Cow<'a, OsStr>
• impl AsRef<Path> for std::ffi::OsString
• impl AsRef<Path> for str
• impl AsRef<Path> for std::string::String
• impl AsRef<Path> for std::path::PathBuf