Trait std::clone::Clone

#[lang = "clone"]
pub trait Clone {
    fn clone(&self) -> Self;

    fn clone_from(&mut self, source: &Self) { ... }
}

A common trait for the ability to explicitly duplicate an object.

Differs from Copy in that Copy is implicit and extremely inexpensive, while Clone is always explicit and may or may not be expensive. In order to enforce these characteristics, Rust does not allow you to reimplement Copy, but you may reimplement Clone and run arbitrary code.

Since Clone is more general than Copy, you can automatically make anything Copy be Clone as well.

Derivable

This trait can be used with #[derive] if all fields are Clone. The derived implementation of clone calls clone on each field.

How can I implement Clone?

Types that are Copy should have a trivial implementation of Clone. More formally: if T: Copy, x: T, and y: &T, then let x = y.clone(); is equivalent to let x = *y;. Manual implementations should be careful to uphold this invariant; however, unsafe code must not rely on it to ensure memory safety.

An example is an array holding more than 32 elements of a type that is Clone; the standard library only implements Clone up until arrays of size 32. In this case, the implementation of Clone cannot be derived, but can be implemented as:

#[derive(Copy)]
struct Stats {
   frequencies: [i32; 100],
}

impl Clone for Stats {
    fn clone(&self) -> Stats { *self }
}

Required Methods

fn clone(&self) -> Self

Returns a copy of the value.

Examples

let hello = "Hello"; // &str implements Clone

assert_eq!("Hello", hello.clone());

Provided Methods

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

a.clone_from(&b) is equivalent to a = b.clone() in functionality, but can be overridden to reuse the resources of a to avoid unnecessary allocations.

Implementations on Foreign Types

impl Clone for __m256d

fn clone(&self) -> __m256d

fn clone_from(&mut self, source: &Self)

impl Clone for __m128

fn clone(&self) -> __m128

fn clone_from(&mut self, source: &Self)

impl Clone for __m256i

fn clone(&self) -> __m256i

fn clone_from(&mut self, source: &Self)

impl Clone for TryFromSliceError

fn clone(&self) -> TryFromSliceError

fn clone_from(&mut self, source: &Self)

impl Clone for __m64

fn clone(&self) -> __m64

fn clone_from(&mut self, source: &Self)

impl Clone for __m256

fn clone(&self) -> __m256

fn clone_from(&mut self, source: &Self)

impl Clone for __m128i

fn clone(&self) -> __m128i

fn clone_from(&mut self, source: &Self)

impl<T> Clone for NonZero<T> where
    T: Zeroable + Clone, 

fn clone(&self) -> NonZero<T>

fn clone_from(&mut self, source: &Self)

impl Clone for __m128d

fn clone(&self) -> __m128d

fn clone_from(&mut self, source: &Self)

impl Clone for CpuidResult

fn clone(&self) -> CpuidResult

fn clone_from(&mut self, source: &Self)

impl<I> Clone for Utf16Encoder<I> where
    I: Clone, 

Important traits for Utf16Encoder<I>

impl<I> Iterator for Utf16Encoder<I> where
    I: Iterator<Item = char>,  type Item = u16;

fn clone(&self) -> Utf16Encoder<I>

fn clone_from(&mut self, source: &Self)

Implementors

• impl<I> Clone for Cloned<I> where
    I: Clone, 
• impl Clone for i64x2
• impl Clone for f64x4
• impl<T> Clone for Option<T> where
    T: Clone, 
• impl Clone for b8x16
• impl<'a, 'b> Clone for StrSearcher<'a, 'b>
• impl Clone for EscapeUnicode
• impl<T, E> Clone for Result<T, E> where
    E: Clone,
    T: Clone, 
• impl<A> Clone for Repeat<A> where
    A: Clone, 
• impl Clone for b8x32
• impl Clone for FpCategory
• impl Clone for u32x8
• impl<'a> Clone for Chars<'a>
• impl Clone for i8x8
• impl Clone for u32x16
• impl Clone for u64x2
• impl<'a, T> Clone for std::slice::Iter<'a, T>
• impl Clone for NonZeroUsize
• impl<T> Clone for RefCell<T> where
    T: Clone, 
• impl Clone for TryFromIntError
• impl<I, F> Clone for FilterMap<I, F> where
    F: Clone,
    I: Clone, 
• impl<T> Clone for NonNull<T> where
    T: ?Sized, 
• impl Clone for i32x16
• impl Clone for ParseCharError
• impl<'a, P> Clone for RMatches<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for NonZeroIsize
• impl Clone for TypeId
• impl Clone for EscapeDebug
• impl<H> Clone for BuildHasherDefault<H>
• impl Clone for u32x2
• impl<I> Clone for Fuse<I> where
    I: Clone, 
• impl<T> Clone for Discriminant<T>
• impl<'a, F> Clone for CharPredicateSearcher<'a, F> where
    F: Clone + FnMut(char) -> bool, 
• impl Clone for f32x4
• impl<'a, P> Clone for MatchIndices<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for SipHasher
• impl Clone for u8x16
• impl<I> Clone for Cycle<I> where
    I: Clone, 
• impl Clone for u8x8
• impl Clone for u16x4
• impl<'a> Clone for CharIndices<'a>
• impl Clone for CharTryFromError
• impl Clone for i8x32
• impl Clone for SearchStep
• impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>
• impl<'a, T> Clone for ExactChunks<'a, T>
• impl<'a, P> Clone for RMatchIndices<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for u8x64
• impl<I, P> Clone for TakeWhile<I, P> where
    I: Clone,
    P: Clone, 
• impl<'a, T> Clone for Windows<'a, T>
• impl Clone for ParseIntError
• impl Clone for b8x8
• impl Clone for Utf8Error
• impl Clone for i16x2
• impl<'a> Clone for LinesAny<'a>
• impl<T> Clone for Cell<T> where
    T: Copy, 
• impl Clone for TraitObject
• impl<Idx> Clone for RangeToInclusive<Idx> where
    Idx: Clone, 
• impl Clone for i16x16
• impl Clone for std::cmp::Ordering
• impl<'a> Clone for Bytes<'a>
• impl Clone for f32x16
• impl Clone for std::sync::atomic::Ordering
• impl Clone for i16x4
• impl Clone for NonZeroU32
• impl Clone for f64x8
• impl<T> Clone for Unique<T> where
    T: ?Sized, 
• impl<'a, P> Clone for SplitTerminator<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<'a, P> Clone for SplitN<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for u64x8
• impl Clone for i32x2
• impl Clone for NonZeroI128
• impl<I, F> Clone for Inspect<I, F> where
    F: Clone,
    I: Clone, 
• impl Clone for i16x32
• impl<'a, T> Clone for Chunks<'a, T>
• impl<A, B> Clone for Zip<A, B> where
    A: Clone,
    B: Clone, 
• impl<I, P> Clone for SkipWhile<I, P> where
    I: Clone,
    P: Clone, 
• impl<Idx> Clone for RangeTo<Idx> where
    Idx: Clone, 
• impl Clone for NonZeroU8
• impl<I, P> Clone for Filter<I, P> where
    I: Clone,
    P: Clone, 
• impl Clone for EscapeDefault
• impl<'a, P> Clone for RSplitN<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<A> Clone for std::option::IntoIter<A> where
    A: Clone, 
• impl<'a, T, P> Clone for std::slice::Split<'a, T, P> where
    P: Clone + FnMut(&T) -> bool, 
• impl Clone for NonZeroI64
• impl<I> Clone for Take<I> where
    I: Clone, 
• impl Clone for Error
• impl<T> Clone for Empty<T>
• impl<T> Clone for std::result::IntoIter<T> where
    T: Clone, 
• impl Clone for u16x16
• impl<T> Clone for Wrapping<T> where
    T: Clone, 
• impl Clone for NonZeroU16
• impl<'a> Clone for Lines<'a>
• impl<'a> Clone for Arguments<'a>
• impl Clone for i32x4
• impl<'a> Clone for CharSearcher<'a>
• impl Clone for NonZeroI32
• impl<I> Clone for Peekable<I> where
    I: Clone + Iterator,
    <I as Iterator>::Item: Clone, 
• impl Clone for RangeFull
• impl<T> Clone for ManuallyDrop<T> where
    T: Clone, 
• impl Clone for i64x8
• impl<T> Clone for Reverse<T> where
    T: Clone, 
• impl<'a, P> Clone for std::str::Split<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<I, U, F> Clone for FlatMap<I, U, F> where
    F: Clone,
    I: Clone,
    U: Clone + IntoIterator,
    <U as IntoIterator>::IntoIter: Clone, 
• impl Clone for b8x64
• impl Clone for Duration
• impl Clone for i8x4
• impl<I, St, F> Clone for Scan<I, St, F> where
    F: Clone,
    I: Clone,
    St: Clone, 
• impl<Idx> Clone for RangeFrom<Idx> where
    Idx: Clone, 
• impl<A, B> Clone for Chain<A, B> where
    A: Clone,
    B: Clone, 
• impl<T> Clone for Rev<T> where
    T: Clone, 
• impl Clone for i16x8
• impl Clone for u16x2
• impl<Idx> Clone for std::ops::Range<Idx> where
    Idx: Clone, 
• impl Clone for u32x4
• impl Clone for i8x64
• impl<I, F> Clone for Map<I, F> where
    F: Clone,
    I: Clone, 
• impl Clone for u64x4
• impl<Y, R> Clone for GeneratorState<Y, R> where
    R: Clone,
    Y: Clone, 
• impl Clone for i8x16
• impl Clone for ParseBoolError
• impl Clone for f32x8
• impl Clone for NonZeroU128
• impl<Idx> Clone for RangeInclusive<Idx> where
    Idx: Clone, 
• impl Clone for b8x4
• impl Clone for NoneError
• impl Clone for NonZeroU64
• impl Clone for f64x2
• impl<F> Clone for RepeatWith<F> where
    F: Clone, 
• impl Clone for u8x4
• impl Clone for u16x8
• impl Clone for u8x32
• impl<T> Clone for Once<T> where
    T: Clone, 
• impl<'a, P> Clone for RSplitTerminator<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for b8x2
• impl<'a, A> Clone for std::option::Iter<'a, A>
• impl Clone for i32x8
• impl<I> Clone for Skip<I> where
    I: Clone, 
• impl Clone for NonZeroI8
• impl<'a, P> Clone for std::str::RSplit<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<'a, P> Clone for Matches<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<T> Clone for PhantomData<T> where
    T: ?Sized, 
• impl<'a, T, P> Clone for std::slice::RSplit<'a, T, P> where
    P: Clone + FnMut(&T) -> bool,
    T: 'a + Clone, 
• impl Clone for NonZeroI16
• impl<I, U> Clone for Flatten<I> where
    I: Iterator + Clone,
    U: Iterator + Clone,
    <I as Iterator>::Item: IntoIterator,
    <<I as Iterator>::Item as IntoIterator>::IntoIter == U,
    <<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item, 
• impl Clone for i64x4
• impl<I> Clone for DecodeUtf8<I> where
    I: Clone + Iterator<Item = u8>, 
• impl Clone for u8x2
• impl<'a, T> Clone for std::result::Iter<'a, T>
• impl<I> Clone for StepBy<I> where
    I: Clone, 
• impl Clone for u16x32
• impl Clone for f32x2
• impl<I> Clone for Enumerate<I> where
    I: Clone, 
• impl Clone for i8x2
• impl Clone for ParseFloatError
• impl Clone for ExchangeHeapSingleton
• impl<T> Clone for Arc<T> where
    T: ?Sized, 
• impl<'a, K, V> Clone for std::collections::btree_map::Values<'a, K, V>
• impl<'a, K, V> Clone for std::collections::btree_map::Iter<'a, K, V>
• impl<'a, K, V> Clone for std::collections::btree_map::Range<'a, K, V>
• impl<T> Clone for std::collections::vec_deque::IntoIter<T> where
    T: Clone, 
• impl<'a, T> Clone for std::collections::btree_set::SymmetricDifference<'a, T>
• impl<'a, T> Clone for std::collections::btree_set::Intersection<'a, T>
• impl<'a, T> Clone for std::collections::btree_set::Union<'a, T>
• impl Clone for String
• impl<'a, T> Clone for std::collections::vec_deque::Iter<'a, T>
• impl<T> Clone for LinkedList<T> where
    T: Clone, 
• impl<T> Clone for BTreeSet<T> where
    T: Clone, 
• impl Clone for Layout
• impl<'a, B> Clone for Cow<'a, B> where
    B: ToOwned + ?Sized, 
• impl<'a> Clone for EncodeUtf16<'a>
• impl<T> Clone for std::rc::Weak<T> where
    T: ?Sized, 
• impl Clone for Box<str>
• impl<'a, T> Clone for std::collections::btree_set::Difference<'a, T>
• impl<T> Clone for BinaryHeap<T> where
    T: Clone, 
• impl Clone for CannotReallocInPlace
• impl<'a, T> Clone for std::collections::btree_set::Range<'a, T>
• impl<'a, T> Clone for std::collections::linked_list::Iter<'a, T>
• impl<'a, T> Clone for std::collections::btree_set::Iter<'a, T>
• impl<'a, T> Clone for std::collections::binary_heap::Iter<'a, T>
• impl<T> Clone for Box<T> where
    T: Clone, 
• impl<T> Clone for std::collections::linked_list::IntoIter<T> where
    T: Clone, 
• impl<T> Clone for std::collections::binary_heap::IntoIter<T> where
    T: Clone, 
• impl<T> Clone for Rc<T> where
    T: ?Sized, 
• impl<'a, K, V> Clone for std::collections::btree_map::Keys<'a, K, V>
• impl<T> Clone for VecDeque<T> where
    T: Clone, 
• impl Clone for Heap
• impl<T> Clone for Vec<T> where
    T: Clone, 
• impl<K, V> Clone for BTreeMap<K, V> where
    K: Clone,
    V: Clone, 
• impl<T> Clone for std::sync::Weak<T> where
    T: ?Sized, 
• impl<T> Clone for std::vec::IntoIter<T> where
    T: Clone, 
• impl Clone for ParseError
• impl<T> Clone for Bound<T> where
    T: Clone, 
• impl<T> Clone for Box<[T]> where
    T: Clone, 
• impl Clone for AllocErr
• impl Clone for CollectionAllocErr
• impl Clone for ToLowercase
• impl<'a> Clone for SplitWhitespace<'a>
• impl Clone for ToUppercase
• impl Clone for UnicodeVersion
• impl Clone for DecodeUtf16Error
• impl<I> Clone for DecodeUtf16<I> where
    I: Clone + Iterator<Item = u16>, 
• impl Clone for ThreadId
• impl Clone for Thread
• impl<K: Clone, V: Clone, S: Clone> Clone for HashMap<K, V, S>
• impl<'a, K, V> Clone for std::collections::hash_map::Iter<'a, K, V>
• impl<'a, K, V> Clone for std::collections::hash_map::Keys<'a, K, V>
• impl<'a, K, V> Clone for std::collections::hash_map::Values<'a, K, V>
• impl Clone for RandomState
• impl Clone for DefaultHasher
• impl<T: Clone, S: Clone> Clone for HashSet<T, S>
• impl<'a, K> Clone for std::collections::hash_set::Iter<'a, K>
• impl<'a, T, S> Clone for std::collections::hash_set::Intersection<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::Difference<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::SymmetricDifference<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::Union<'a, T, S>
• impl Clone for VarError
• impl Clone for CString
• impl Clone for NulError
• impl Clone for FromBytesWithNulError
• impl Clone for IntoStringError
• impl Clone for OsString
• impl Clone for Metadata
• impl Clone for OpenOptions
• impl Clone for Permissions
• impl Clone for FileType
• impl<T: Clone> Clone for Cursor<T>
• impl Clone for ErrorKind
• impl Clone for SeekFrom
• impl Clone for IpAddr
• impl Clone for Ipv6MulticastScope
• impl Clone for Ipv4Addr
• impl Clone for Ipv6Addr
• impl Clone for std::net::SocketAddr
• impl Clone for SocketAddrV4
• impl Clone for SocketAddrV6
• impl Clone for AddrParseError
• impl Clone for Shutdown
• impl Clone for stat
• impl<'a> Clone for Prefix<'a>
• impl<'a> Clone for PrefixComponent<'a>
• impl<'a> Clone for Component<'a>
• impl<'a> Clone for Components<'a>
• impl<'a> Clone for std::path::Iter<'a>
• impl<'a> Clone for Ancestors<'a>
• impl Clone for PathBuf
• impl Clone for ParsePathError
• impl Clone for StripPrefixError
• impl Clone for Output
• impl Clone for ExitStatus
• impl Clone for ExitCode
• impl<T: Clone> Clone for SendError<T>
• impl Clone for RecvError
• impl Clone for TryRecvError
• impl Clone for RecvTimeoutError
• impl<T: Clone> Clone for TrySendError<T>
• impl<T> Clone for Sender<T>
• impl<T> Clone for SyncSender<T>
• impl Clone for WaitTimeoutResult
• impl Clone for Instant
• impl Clone for SystemTime
• impl Clone for SystemTimeError
• impl<'a> Clone for EncodeWide<'a>
• impl Clone for std::os::unix::net::SocketAddr