Trait core::clone::Clone 1.0.0[−][src]
#[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.
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 } }Run
Additional implementors
In addition to the implementors listed below,
the following types also implement Clone:
- Function item types (i.e. the distinct types defined for each function)
- Function pointer types (e.g.
fn() -> i32) - Array types, for all sizes, if the item type also implements
Clone(e.g.[i32; 123456]) - Tuple types, if each component also implements
Clone(e.g.(),(i32, bool)) - Closure types, if they capture no value from the environment
or if all such captured values implement
Clonethemselves. Note that variables captured by shared reference always implementClone(even if the referent doesn't), while variables captured by mutable reference never implementClone.
Required Methods
#[must_use = "cloning is often expensive and is not expected to have side effects"]
fn clone(&self) -> Self
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.
Implementors
impl Clone for ParseFloatErrorimpl Clone for NonZeroU8impl Clone for NonZeroU16impl Clone for NonZeroU32impl Clone for NonZeroU64impl Clone for NonZeroU128impl Clone for NonZeroUsizeimpl<T: Clone> Clone for Wrapping<T>impl Clone for FpCategoryimpl Clone for TryFromIntErrorimpl Clone for ParseIntErrorimpl<T> Clone for Discriminant<T>impl<T: Clone> Clone for ManuallyDrop<T>impl<T: ?Sized> Clone for NonNull<T>impl<T: ?Sized> Clone for PhantomData<T>impl Clone for Pinnedimpl<Y: Clone, R: Clone> Clone for GeneratorState<Y, R>impl Clone for RangeFullimpl<Idx: Clone> Clone for Range<Idx>impl<Idx: Clone> Clone for RangeFrom<Idx>impl<Idx: Clone> Clone for RangeTo<Idx>impl<Idx: Clone> Clone for RangeInclusive<Idx>impl<Idx: Clone> Clone for RangeToInclusive<Idx>impl<T: Clone> Clone for Bound<T>impl Clone for core::cmp::Orderingimpl<T: Clone> Clone for Reverse<T>impl Clone for usizeimpl Clone for u8impl Clone for u16impl Clone for u32impl Clone for u64impl Clone for u128impl Clone for isizeimpl Clone for i8impl Clone for i16impl Clone for i32impl Clone for i64impl Clone for i128impl Clone for f32impl Clone for f64impl Clone for boolimpl Clone for charimpl Clone for !impl<T: ?Sized> Clone for *const Timpl<T: ?Sized> Clone for *mut Timpl<'a, T: ?Sized> Clone for &'a Timpl Clone for TypeIdimpl Clone for TryFromSliceErrorimpl Clone for core::sync::atomic::Orderingimpl<T: Copy> Clone for Cell<T>impl<T: Clone> Clone for RefCell<T>impl Clone for ParseCharErrorimpl Clone for CharTryFromErrorimpl<I: Clone + Iterator<Item = u8>> Clone for DecodeUtf8<I>impl<I: Clone> Clone for DecodeUtf16<I> where
I: Iterator<Item = u16>,impl Clone for DecodeUtf16Errorimpl Clone for EscapeUnicodeimpl Clone for EscapeDefaultimpl Clone for EscapeDebugimpl Clone for ToLowercaseimpl Clone for ToUppercaseimpl<A: Clone> Clone for Repeat<A>impl<F: Clone> Clone for RepeatWith<F>impl<T> Clone for Empty<T>impl<T: Clone> Clone for Once<T>impl<T: Clone> Clone for Rev<T>impl<I: Clone> Clone for Cloned<I>impl<I: Clone> Clone for Cycle<I>impl<I: Clone> Clone for StepBy<I>impl<A: Clone, B: Clone> Clone for Chain<A, B>impl<A: Clone, B: Clone> Clone for Zip<A, B>impl<I: Clone, F: Clone> Clone for Map<I, F>impl<I: Clone, P: Clone> Clone for Filter<I, P>impl<I: Clone, F: Clone> Clone for FilterMap<I, F>impl<I: Clone> Clone for Enumerate<I>impl<I: Clone + Iterator> Clone for Peekable<I> where
I::Item: Clone,impl<I: Clone, P: Clone> Clone for SkipWhile<I, P>impl<I: Clone, P: Clone> Clone for TakeWhile<I, P>impl<I: Clone> Clone for Skip<I>impl<I: Clone> Clone for Take<I>impl<I: Clone, St: Clone, F: Clone> Clone for Scan<I, St, F>impl<I: Clone, U: Clone + IntoIterator, F: Clone> Clone for FlatMap<I, U, F> where
<U as IntoIterator>::IntoIter: Clone,impl<I, U> Clone for Flatten<I> where
I: Iterator + Clone,
U: Iterator + Clone,
I::Item: IntoIterator<IntoIter = U, Item = U::Item>,impl<I: Clone> Clone for Fuse<I>impl<I: Clone, F: Clone> Clone for Inspect<I, F>impl<T: Clone> Clone for Option<T>impl<'a, A> Clone for core::option::Iter<'a, A>impl<A: Clone> Clone for core::option::IntoIter<A>impl Clone for NoneErrorimpl Clone for TraitObjectimpl<T: Clone, E: Clone> Clone for Result<T, E>impl<'a, T> Clone for core::result::Iter<'a, T>impl<T: Clone> Clone for core::result::IntoIter<T>impl<'a, T> Clone for core::slice::Iter<'a, T>impl<'a, T, P> Clone for core::slice::Split<'a, T, P> where
P: Clone + FnMut(&T) -> bool,impl<'a, T: Clone + 'a, P: Clone> Clone for core::slice::RSplit<'a, T, P> where
P: FnMut(&T) -> bool,impl<'a, T> Clone for Windows<'a, T>impl<'a, T> Clone for Chunks<'a, T>impl<'a, T> Clone for ExactChunks<'a, T>impl Clone for SearchStepimpl<'a> Clone for CharSearcher<'a>impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>impl<'a, F: Clone> Clone for CharPredicateSearcher<'a, F> where
F: FnMut(char) -> bool,impl<'a, 'b> Clone for StrSearcher<'a, 'b>impl Clone for ParseBoolErrorimpl Clone for Utf8Errorimpl<'a> Clone for Chars<'a>impl<'a> Clone for CharIndices<'a>impl<'a> Clone for Bytes<'a>impl<'a, P: Pattern<'a>> Clone for core::str::Split<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for core::str::RSplit<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for SplitTerminator<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for RSplitTerminator<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for SplitN<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for RSplitN<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for MatchIndices<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for RMatchIndices<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for Matches<'a, P> where
P::Searcher: Clone,impl<'a, P: Pattern<'a>> Clone for RMatches<'a, P> where
P::Searcher: Clone,impl<'a> Clone for Lines<'a>impl<'a> Clone for LinesAny<'a>impl<'a> Clone for SplitWhitespace<'a>impl<'a> Clone for SplitAsciiWhitespace<'a>impl<'a> Clone for EncodeUtf16<'a>impl Clone for SipHasherimpl<H> Clone for BuildHasherDefault<H>impl Clone for Errorimpl<'a> Clone for Arguments<'a>impl Clone for Durationimpl Clone for UnicodeVersionimpl<T: Clone> Clone for Poll<T>impl Clone for Wakerimpl Clone for LocalWakerimpl Clone for Layoutimpl Clone for LayoutErrimpl Clone for AllocErrimpl Clone for CannotReallocInPlaceimpl Clone for CpuidResultimpl Clone for __m64impl Clone for __m128iimpl Clone for __m128impl Clone for __m128dimpl Clone for __m256iimpl Clone for __m256impl Clone for __m256dimpl Clone for float64x1_timpl Clone for float64x2_timpl Clone for int8x4_timpl Clone for uint8x4_timpl Clone for int16x2_timpl Clone for uint16x2_timpl Clone for int8x8_timpl Clone for uint8x8_timpl Clone for poly8x8_timpl Clone for int16x4_timpl Clone for uint16x4_timpl Clone for poly16x4_timpl Clone for int32x2_timpl Clone for uint32x2_timpl Clone for float32x2_timpl Clone for int64x1_timpl Clone for uint64x1_timpl Clone for int8x16_timpl Clone for uint8x16_timpl Clone for poly8x16_timpl Clone for int16x8_timpl Clone for uint16x8_timpl Clone for poly16x8_timpl Clone for int32x4_timpl Clone for uint32x4_timpl Clone for float32x4_timpl Clone for int64x2_timpl Clone for uint64x2_timpl Clone for i8x16impl Clone for vector_signed_longimpl Clone for vector_unsigned_longimpl Clone for vector_bool_longimpl Clone for vector_double