1.0.0[][src]Trait core::clone::Clone

#[lang = "clone"]
pub trait Clone: Sized {
#[must_use = "cloning is often expensive and is not expected to have side effects"]
    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.

For a generic struct, #[derive] implements Clone conditionally by adding bound Clone on generic parameters.

// `derive` implements Clone for Reading<T> when T is Clone.
#[derive(Clone)]
struct Reading<T> {
    frequency: T,
}Run

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 a generic struct holding a function pointer. In this case, the implementation of Clone cannot be derived, but can be implemented as:

struct Generate<T>(fn() -> T);

impl<T> Copy for Generate<T> {}

impl<T> Clone for Generate<T> {
    fn clone(&self) -> Self {
        *self
    }
}Run

Additional implementors

In addition to the implementors listed below, the following types also implement Clone:

Required methods

#[must_use = "cloning is often expensive and is not expected to have side effects"] fn clone(&self) -> Self

Returns a copy of the value.

Examples

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

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

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Implementors

impl Clone for ![src]

impl Clone for core::cmp::Ordering[src]

impl Clone for Infallible[src]

impl Clone for FpCategory[src]

impl Clone for IntErrorKind[src]

impl Clone for SearchStep[src]

impl Clone for core::sync::atomic::Ordering[src]

impl Clone for AllocErr[src]

impl Clone for CannotReallocInPlace[src]

impl Clone for Layout[src]

impl Clone for LayoutErr[src]

impl Clone for TypeId[src]

impl Clone for float64x1_t[src]

impl Clone for float64x2_t[src]

impl Clone for int8x16x2_t[src]

impl Clone for int8x16x3_t[src]

impl Clone for int8x16x4_t[src]

impl Clone for poly64x1_t[src]

impl Clone for poly64x2_t[src]

impl Clone for poly8x16x2_t[src]

impl Clone for poly8x16x3_t[src]

impl Clone for poly8x16x4_t[src]

impl Clone for uint8x16x2_t[src]

impl Clone for uint8x16x3_t[src]

impl Clone for uint8x16x4_t[src]

impl Clone for float32x2_t[src]

impl Clone for float32x4_t[src]

impl Clone for int16x4_t[src]

impl Clone for int16x8_t[src]

impl Clone for int32x2_t[src]

impl Clone for int32x4_t[src]

impl Clone for int64x1_t[src]

impl Clone for int64x2_t[src]

impl Clone for int8x16_t[src]

impl Clone for int8x8_t[src]

impl Clone for int8x8x2_t[src]

impl Clone for int8x8x3_t[src]

impl Clone for int8x8x4_t[src]

impl Clone for poly16x4_t[src]

impl Clone for poly16x8_t[src]

impl Clone for poly8x16_t[src]

impl Clone for poly8x8_t[src]

impl Clone for poly8x8x2_t[src]

impl Clone for poly8x8x3_t[src]

impl Clone for poly8x8x4_t[src]

impl Clone for uint16x4_t[src]

impl Clone for uint16x8_t[src]

impl Clone for uint32x2_t[src]

impl Clone for uint32x4_t[src]

impl Clone for uint64x1_t[src]

impl Clone for uint64x2_t[src]

impl Clone for uint8x16_t[src]

impl Clone for uint8x8_t[src]

impl Clone for uint8x8x2_t[src]

impl Clone for uint8x8x3_t[src]

impl Clone for uint8x8x4_t[src]

impl Clone for v16i8[src]

impl Clone for v16u8[src]

impl Clone for v2f64[src]

impl Clone for v2i64[src]

impl Clone for v2u64[src]

impl Clone for v4f32[src]

impl Clone for v4i32[src]

impl Clone for v4u32[src]

impl Clone for v8i16[src]

impl Clone for v8u16[src]

impl Clone for vector_bool_long[src]

impl Clone for vector_double[src]

impl Clone for vector_signed_long[src]

impl Clone for vector_unsigned_long[src]

impl Clone for v128[src]

impl Clone for CpuidResult[src]

impl Clone for __m128[src]

impl Clone for __m128d[src]

impl Clone for __m128i[src]

impl Clone for __m256[src]

impl Clone for __m256d[src]

impl Clone for __m256i[src]

impl Clone for __m512[src]

impl Clone for __m512d[src]

impl Clone for __m512i[src]

impl Clone for __m64[src]

impl Clone for TryFromSliceError[src]

impl Clone for CharTryFromError[src]

impl Clone for DecodeUtf16Error[src]

impl Clone for core::char::EscapeDebug[src]

impl Clone for core::char::EscapeDefault[src]

impl Clone for core::char::EscapeUnicode[src]

impl Clone for ParseCharError[src]

impl Clone for ToLowercase[src]

impl Clone for ToUppercase[src]

impl Clone for UnicodeVersion[src]

impl Clone for Error[src]

impl Clone for SipHasher[src]

impl Clone for PhantomPinned[src]

impl Clone for NonZeroI128[src]

impl Clone for NonZeroI16[src]

impl Clone for NonZeroI32[src]

impl Clone for NonZeroI64[src]

impl Clone for NonZeroI8[src]

impl Clone for NonZeroIsize[src]

impl Clone for NonZeroU128[src]

impl Clone for NonZeroU16[src]

impl Clone for NonZeroU32[src]

impl Clone for NonZeroU64[src]

impl Clone for NonZeroU8[src]

impl Clone for NonZeroUsize[src]

impl Clone for ParseFloatError[src]

impl Clone for ParseIntError[src]

impl Clone for TryFromIntError[src]

impl Clone for RangeFull[src]

impl Clone for NoneError[src]

impl Clone for TraitObject[src]

impl Clone for ParseBoolError[src]

impl Clone for Utf8Error[src]

impl Clone for RawWakerVTable[src]

impl Clone for Waker[src]

impl Clone for Duration[src]

impl Clone for bool[src]

impl Clone for char[src]

impl Clone for f32[src]

impl Clone for f64[src]

impl Clone for i8[src]

impl Clone for i16[src]

impl Clone for i32[src]

impl Clone for i64[src]

impl Clone for i128[src]

impl Clone for isize[src]

impl Clone for u8[src]

impl Clone for u16[src]

impl Clone for u32[src]

impl Clone for u64[src]

impl Clone for u128[src]

impl Clone for usize[src]

impl<'_, A> Clone for core::option::Iter<'_, A>[src]

impl<'_, T> Clone for core::result::Iter<'_, T>[src]

impl<'_, T> Clone for Chunks<'_, T>[src]

impl<'_, T> Clone for ChunksExact<'_, T>[src]

impl<'_, T> Clone for core::slice::Iter<'_, T>[src]

impl<'_, T> Clone for RChunks<'_, T>[src]

impl<'_, T> Clone for Windows<'_, T>[src]

impl<'_, T, P> Clone for core::slice::Split<'_, T, P> where
    P: Clone + FnMut(&T) -> bool, 
[src]

impl<'_, T: ?Sized> Clone for &'_ T[src]

impl<'a> Clone for Arguments<'a>[src]

impl<'a> Clone for CharSearcher<'a>[src]

impl<'a> Clone for Bytes<'a>[src]

impl<'a> Clone for CharIndices<'a>[src]

impl<'a> Clone for Chars<'a>[src]

impl<'a> Clone for EncodeUtf16<'a>[src]

impl<'a> Clone for core::str::EscapeDebug<'a>[src]

impl<'a> Clone for core::str::EscapeDefault<'a>[src]

impl<'a> Clone for core::str::EscapeUnicode<'a>[src]

impl<'a> Clone for Lines<'a>[src]

impl<'a> Clone for LinesAny<'a>[src]

impl<'a> Clone for SplitAsciiWhitespace<'a>[src]

impl<'a> Clone for SplitWhitespace<'a>[src]

impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>[src]

impl<'a, 'b> Clone for StrSearcher<'a, 'b>[src]

impl<'a, F: Clone> Clone for CharPredicateSearcher<'a, F> where
    F: FnMut(char) -> bool, 
[src]

impl<'a, P> Clone for MatchIndices<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for Matches<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for RMatchIndices<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for RMatches<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for core::str::RSplit<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for RSplitN<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for RSplitTerminator<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for core::str::Split<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for SplitN<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, P> Clone for SplitTerminator<'a, P> where
    P: Pattern<'a, Searcher: Clone>, 
[src]

impl<'a, T> Clone for RChunksExact<'a, T>[src]

impl<'a, T: Clone + 'a, P: Clone> Clone for core::slice::RSplit<'a, T, P> where
    P: FnMut(&T) -> bool, 
[src]

impl<'f> Clone for VaListImpl<'f>[src]

impl<A: Clone> Clone for Repeat<A>[src]

impl<A: Clone> Clone for core::option::IntoIter<A>[src]

impl<A: Clone, B: Clone> Clone for Chain<A, B>[src]

impl<A: Clone, B: Clone> Clone for Zip<A, B>[src]

impl<F: Clone> Clone for FromFn<F>[src]

impl<F: Clone> Clone for OnceWith<F>[src]

impl<F: Clone> Clone for RepeatWith<F>[src]

impl<H> Clone for BuildHasherDefault<H>[src]

impl<I, U> Clone for Flatten<I> where
    I: Clone + Iterator<Item: IntoIterator<IntoIter = U, Item = U::Item>>,
    U: Clone + Iterator
[src]

impl<I: Clone + Iterator> Clone for Peekable<I> where
    I::Item: Clone
[src]

impl<I: Clone> Clone for DecodeUtf16<I> where
    I: Iterator<Item = u16>, 
[src]

impl<I: Clone> Clone for Cloned<I>[src]

impl<I: Clone> Clone for Copied<I>[src]

impl<I: Clone> Clone for Cycle<I>[src]

impl<I: Clone> Clone for Enumerate<I>[src]

impl<I: Clone> Clone for Fuse<I>[src]

impl<I: Clone> Clone for Skip<I>[src]

impl<I: Clone> Clone for StepBy<I>[src]

impl<I: Clone> Clone for Take<I>[src]

impl<I: Clone, F: Clone> Clone for FilterMap<I, F>[src]

impl<I: Clone, F: Clone> Clone for Inspect<I, F>[src]

impl<I: Clone, F: Clone> Clone for Map<I, F>[src]

impl<I: Clone, P: Clone> Clone for Filter<I, P>[src]

impl<I: Clone, P: Clone> Clone for SkipWhile<I, P>[src]

impl<I: Clone, P: Clone> Clone for TakeWhile<I, P>[src]

impl<I: Clone, St: Clone, F: Clone> Clone for Scan<I, St, F>[src]

impl<I: Clone, U, F: Clone> Clone for FlatMap<I, U, F> where
    U: Clone + IntoIterator<IntoIter: Clone>, 
[src]

impl<Idx: Clone> Clone for Range<Idx>[src]

impl<Idx: Clone> Clone for RangeFrom<Idx>[src]

impl<Idx: Clone> Clone for RangeInclusive<Idx>[src]

impl<Idx: Clone> Clone for RangeTo<Idx>[src]

impl<Idx: Clone> Clone for RangeToInclusive<Idx>[src]

impl<P: Clone> Clone for Pin<P>[src]

impl<T> Clone for Empty<T>[src]

impl<T> Clone for Discriminant<T>[src]

impl<T: Clone + ?Sized> Clone for ManuallyDrop<T>[src]

impl<T: Clone> Clone for Bound<T>[src]

impl<T: Clone> Clone for Option<T>[src]

impl<T: Clone> Clone for Poll<T>[src]

impl<T: Clone> Clone for RefCell<T>[src]

fn clone(&self) -> RefCell<T>[src]

Panics

Panics if the value is currently mutably borrowed.

impl<T: Clone> Clone for Reverse<T>[src]

impl<T: Clone> Clone for Once<T>[src]

impl<T: Clone> Clone for Rev<T>[src]

impl<T: Clone> Clone for Wrapping<T>[src]

impl<T: Clone> Clone for core::result::IntoIter<T>[src]

impl<T: Clone, E: Clone> Clone for Result<T, E>[src]

impl<T: Clone, F: Clone> Clone for Successors<T, F>[src]

impl<T: Copy> Clone for Cell<T>[src]

impl<T: Copy> Clone for MaybeUninit<T>[src]

impl<T: ?Sized> Clone for *const T[src]

impl<T: ?Sized> Clone for *mut T[src]

impl<T: ?Sized> Clone for PhantomData<T>[src]

impl<T: ?Sized> Clone for NonNull<T>[src]

impl<Y: Clone, R: Clone> Clone for GeneratorState<Y, R>[src]

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