1.0.0[−][src]Trait sp_std::ops::Deref

[+] Show declaration

[+] Expand attributes
#[lang = "deref"]pub trait Deref {
    type Target: ?Sized;
[+] Expand attributes
#[must_use]    fn deref(&self) -> &Self::Target;
}

[−]

Used for immutable dereferencing operations, like *v.

In addition to being used for explicit dereferencing operations with the (unary) * operator in immutable contexts, Deref is also used implicitly by the compiler in many circumstances. This mechanism is called 'Deref coercion'. In mutable contexts, DerefMut is used.

Implementing Deref for smart pointers makes accessing the data behind them convenient, which is why they implement Deref. On the other hand, the rules regarding Deref and DerefMut were designed specifically to accommodate smart pointers. Because of this, Deref should only be implemented for smart pointers to avoid confusion.

For similar reasons, this trait should never fail. Failure during dereferencing can be extremely confusing when Deref is invoked implicitly.

More on `Deref` coercion

If T implements Deref<Target = U>, and x is a value of type T, then:

In immutable contexts, *x (where T is neither a reference nor a raw pointer) is equivalent to *Deref::deref(&x).
Values of type &T are coerced to values of type &U
T implicitly implements all the (immutable) methods of the type U.

For more details, visit the chapter in The Rust Programming Language as well as the reference sections on the dereference operator, method resolution and type coercions.

Examples

A struct with a single field which is accessible by dereferencing the struct.

use std::ops::Deref;

struct DerefExample<T> {
    value: T
}

impl<T> Deref for DerefExample<T> {
    type Target = T;

    fn deref(&self) -> &Self::Target {
        &self.value
    }
}

let x = DerefExample { value: 'a' };
assert_eq!('a', *x);

Associated Types

`type Target: ?Sized`[−]

The resulting type after dereferencing.

Required methods

`[+] Expand attributes #[must_use]fn deref(&self) -> &Self::Target`[−]

Dereferences the value.

1.0.0[−][src]Trait sp_std::ops::Deref

More on Deref coercion

Examples

Associated Types

type Target: ?Sized[−]

Required methods

[+] Expand attributes#[must_use]fn deref(&self) -> &Self::Target[−]

Implementations on Foreign Types

impl Deref for PathBuf[src][−]

type Target = Path

fn deref(&self) -> &Path[src]

impl<'a> Deref for IoSlice<'a>[src][−]

type Target = [u8]

fn deref(&self) -> &[u8]ⓘNotable traits for &'_ mut [u8]impl<'_> Write for &'_ mut [u8]impl<'_> Read for &'_ [u8][src]

Notable traits for &'_ mut [u8]

impl<'a> Deref for IoSliceMut<'a>[src][−]

type Target = [u8]

fn deref(&self) -> &[u8]ⓘNotable traits for &'_ mut [u8]impl<'_> Write for &'_ mut [u8]impl<'_> Read for &'_ [u8][src]

Notable traits for &'_ mut [u8]

impl<T> Deref for AssertUnwindSafe<T>[src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl Deref for OsString[src][−]

type Target = OsStr

fn deref(&self) -> &OsStr[src]

impl Deref for CString[src][−]

type Target = CStr

fn deref(&self) -> &CStr[src]

impl<T, F> Deref for SyncLazy<T, F> where F: FnOnce() -> T, [src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'_, T> Deref for &'_ mut T where T: ?Sized, [src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<P> Deref for Pin<P> where P: Deref, [src][−]

type Target = <P as Deref>::Target

fn deref(&self) -> &<P as Deref>::Target[src]

impl<T, F> Deref for Lazy<T, F> where F: FnOnce() -> T, [src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'a, 'f> Deref for VaList<'a, 'f> where 'f: 'a, [src][−]

type Target = VaListImpl<'f>

fn deref(&self) -> &VaListImpl<'f>[src]

impl<'_, T> Deref for &'_ T where T: ?Sized, [src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl Deref for String[src][−]

type Target = str

fn deref(&self) -> &str[src]

impl<'_, T> Deref for PeekMut<'_, T> where T: Ord, [src][−]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'input, Endian> Deref for EndianSlice<'input, Endian> where Endian: Endianity, [src][−]

type Target = [u8]

fn deref(&self) -> &<EndianSlice<'input, Endian> as Deref>::Target[src]

Implementors

impl<'_, B> Deref for Cow<'_, B> where B: ToOwned + ?Sized, [src][+]

type Target = B

fn deref(&self) -> &BⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'_, T> Deref for Ref<'_, T> where T: ?Sized, [src][+]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'_, T> Deref for RefMut<'_, T> where T: ?Sized, [src][+]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'_, T> Deref for MutexGuard<'_, T> where T: ?Sized, [src][+]

type Target = T

fn deref(&self) -> &TⓘNotable traits for &'_ mut Iimpl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;[src]

Notable traits for &'_ mut I

impl<'_, T> Deref for RwLockReadGuard<'_, T> where T: ?Sized, [src][+]

type Target = T

More on `Deref` coercion

`type Target: ?Sized`[−]

`[+] Expand attributes #[must_use]fn deref(&self) -> &Self::Target`[−]

`impl Deref for PathBuf`[src][−]

`type Target = Path`

`fn deref(&self) -> &Path`[src]

`impl<'a> Deref for IoSlice<'a>`[src][−]

`type Target = [u8]`

`fn deref(&self) -> &[u8]ⓘNotable traits for &'_ mut [u8] impl<'_> Write for &'_ mut [u8]impl<'_> Read for &'_ [u8]`[src]

Notable traits for &'_ mut [u8 ]

`impl<'a> Deref for IoSliceMut<'a>`[src][−]

`type Target = [u8]`

`fn deref(&self) -> &[u8]ⓘNotable traits for &'_ mut [u8] impl<'_> Write for &'_ mut [u8]impl<'_> Read for &'_ [u8]`[src]

Notable traits for &'_ mut [u8 ]

`impl<T> Deref for AssertUnwindSafe<T>`[src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl Deref for OsString`[src][−]

`type Target = OsStr`

`fn deref(&self) -> &OsStr`[src]

`impl Deref for CString`[src][−]

`type Target = CStr`

`fn deref(&self) -> &CStr`[src]

`impl<T, F> Deref for SyncLazy<T, F> where F: FnOnce() -> T,` [src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for &'_ mut T where T: ?Sized,` [src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<P> Deref for Pin<P> where P: Deref,` [src][−]

`type Target = <P as Deref>::Target`

`fn deref(&self) -> &<P as Deref>::Target`[src]

`impl<T, F> Deref for Lazy<T, F> where F: FnOnce() -> T,` [src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'a, 'f> Deref for VaList<'a, 'f> where 'f: 'a,` [src][−]

`type Target = VaListImpl<'f>`

`fn deref(&self) -> &VaListImpl<'f>`[src]

`impl<'_, T> Deref for &'_ T where T: ?Sized,` [src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl Deref for String`[src][−]

`type Target = str`

`fn deref(&self) -> &str`[src]

`impl<'_, T> Deref for PeekMut<'_, T> where T: Ord,` [src][−]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'input, Endian> Deref for EndianSlice<'input, Endian> where Endian: Endianity,` [src][−]

`type Target = [u8]`

`fn deref(&self) -> &<EndianSlice<'input, Endian> as Deref>::Target`[src]

`impl<'_, B> Deref for Cow<'_, B> where B: ToOwned + ?Sized,` [src][+]

`type Target = B`

`fn deref(&self) -> &BⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for Ref<'_, T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for RefMut<'_, T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for MutexGuard<'_, T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for RwLockReadGuard<'_, T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<'_, T> Deref for RwLockWriteGuard<'_, T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<T> Deref for ManuallyDrop<T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<T> Deref for Box<T> where T: ?Sized,` [src][+]

`type Target = T`

`fn deref(&self) -> &TⓘNotable traits for &'_ mut I impl<'_, I> Iterator for &'_ mut I where I: Iterator + ?Sized, type Item = <I as Iterator>::Item;`[src]

`impl<T> Deref for Vec<T>`[src][+]

`type Target = [T]`

`fn deref(&self) -> &[T]ⓘNotable traits for &'_ mut [u8] impl<'_> Write for &'_ mut [u8]impl<'_> Read for &'_ [u8]`[src]

Notable traits for &'_ mut [u8 ]

`impl<T> Deref for Rc<T> where T: ?Sized,` [src][+]

`type Target = T`