1.0.0[−][src]Trait core_futures_tls::prelude::v1::Clone
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 derive
d
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, }
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 derive
d, 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 } }
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
Clone
themselves. 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
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 ParseFloatError
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fn clone(&self) -> ParseFloatError
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Implementors
impl Clone for NoneError
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impl Clone for AllocErr
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impl Clone for usize
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impl Clone for ParseIntError
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fn clone(&self) -> ParseIntError
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impl Clone for core_futures_tls::char::EscapeDebug
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ⓘImportant traits for EscapeDebugfn clone(&self) -> EscapeDebug
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impl Clone for ToLowercase
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ⓘImportant traits for ToLowercasefn clone(&self) -> ToLowercase
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impl Clone for CannotReallocInPlace
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fn clone(&self) -> CannotReallocInPlace
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impl Clone for RangeFull
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impl Clone for UnicodeVersion
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fn clone(&self) -> UnicodeVersion
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impl Clone for LayoutErr
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impl Clone for TryFromSliceError
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fn clone(&self) -> TryFromSliceError
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impl Clone for TraitObject
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fn clone(&self) -> TraitObject
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impl Clone for Duration
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impl Clone for Infallible
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fn clone(&self) -> Infallible
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impl Clone for core_futures_tls::char::EscapeDefault
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ⓘImportant traits for EscapeDefaultfn clone(&self) -> EscapeDefault
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impl Clone for TypeId
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impl Clone for PhantomPinned
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fn clone(&self) -> PhantomPinned
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impl Clone for TryFromIntError
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fn clone(&self) -> TryFromIntError
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impl Clone for core_futures_tls::char::EscapeUnicode
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ⓘImportant traits for EscapeUnicodefn clone(&self) -> EscapeUnicode
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impl Clone for Layout
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impl Clone for bool
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impl Clone for !
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impl Clone for Waker
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impl Clone for char
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impl Clone for NonZeroUsize
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fn clone(&self) -> NonZeroUsize
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impl Clone for core_futures_tls::cmp::Ordering
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impl Clone for SearchStep
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fn clone(&self) -> SearchStep
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impl Clone for ToUppercase
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ⓘImportant traits for ToUppercasefn clone(&self) -> ToUppercase
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impl Clone for FpCategory
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fn clone(&self) -> FpCategory
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impl Clone for core_futures_tls::sync::atomic::Ordering
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impl Clone for CharTryFromError
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fn clone(&self) -> CharTryFromError
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impl Clone for ParseBoolError
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fn clone(&self) -> ParseBoolError
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impl Clone for SipHasher
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impl Clone for RawWakerVTable
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fn clone(&self) -> RawWakerVTable
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impl Clone for IntErrorKind
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fn clone(&self) -> IntErrorKind
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impl Clone for NonZeroIsize
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fn clone(&self) -> NonZeroIsize
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impl Clone for ParseCharError
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fn clone(&self) -> ParseCharError
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impl Clone for Error
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impl Clone for isize
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impl Clone for CpuidResult
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fn clone(&self) -> CpuidResult
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impl Clone for __m128
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impl Clone for __m128d
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impl Clone for __m128i
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impl Clone for __m256
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impl Clone for __m256d
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impl Clone for __m256i
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impl Clone for __m512
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impl Clone for __m512d
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impl Clone for __m512i
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impl Clone for __m64
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impl Clone for DecodeUtf16Error
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fn clone(&self) -> DecodeUtf16Error
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impl Clone for NonZeroI128
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fn clone(&self) -> NonZeroI128
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impl Clone for NonZeroI16
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fn clone(&self) -> NonZeroI16
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impl Clone for NonZeroI32
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fn clone(&self) -> NonZeroI32
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impl Clone for NonZeroI64
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fn clone(&self) -> NonZeroI64
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impl Clone for NonZeroI8
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impl Clone for NonZeroU128
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fn clone(&self) -> NonZeroU128
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impl Clone for NonZeroU16
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fn clone(&self) -> NonZeroU16
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impl Clone for NonZeroU32
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fn clone(&self) -> NonZeroU32
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impl Clone for NonZeroU64
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fn clone(&self) -> NonZeroU64
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impl Clone for NonZeroU8
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impl Clone for Utf8Error
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impl Clone for f32
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impl Clone for f64
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impl Clone for i8
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impl Clone for i16
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impl Clone for i32
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impl Clone for i64
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impl Clone for i128
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impl Clone for u8
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impl Clone for u16
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impl Clone for u32
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impl Clone for u64
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impl Clone for u128
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impl<'_, A> Clone for core_futures_tls::option::Iter<'_, A>
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impl<'_, T> Clone for core_futures_tls::result::Iter<'_, T>
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impl<'_, T> Clone for ChunksExact<'_, T>
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ⓘImportant traits for ChunksExact<'a, T>fn clone(&self) -> ChunksExact<'_, T>
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impl<'_, T> Clone for core_futures_tls::slice::Iter<'_, T>
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impl<'_, T> Clone for Windows<'_, T>
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impl<'_, T> Clone for RChunks<'_, T>
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impl<'_, T> Clone for Chunks<'_, T>
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impl<'_, T> Clone for &'_ T where
T: ?Sized,
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T: ?Sized,
impl<'_, T, P> Clone for core_futures_tls::slice::Split<'_, T, P> where
P: Clone + FnMut(&T) -> bool,
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P: Clone + FnMut(&T) -> bool,
impl<'a> Clone for Bytes<'a>
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impl<'a> Clone for LinesAny<'a>
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impl<'a> Clone for SplitAsciiWhitespace<'a>
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ⓘImportant traits for SplitAsciiWhitespace<'a>fn clone(&self) -> SplitAsciiWhitespace<'a>
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impl<'a> Clone for Arguments<'a>
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impl<'a> Clone for Chars<'a>
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impl<'a> Clone for CharIndices<'a>
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ⓘImportant traits for CharIndices<'a>fn clone(&self) -> CharIndices<'a>
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impl<'a> Clone for core_futures_tls::str::EscapeDefault<'a>
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ⓘImportant traits for EscapeDefault<'a>fn clone(&self) -> EscapeDefault<'a>
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impl<'a> Clone for SplitWhitespace<'a>
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ⓘImportant traits for SplitWhitespace<'a>fn clone(&self) -> SplitWhitespace<'a>
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impl<'a> Clone for CharSearcher<'a>
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fn clone(&self) -> CharSearcher<'a>
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impl<'a> Clone for core_futures_tls::str::EscapeDebug<'a>
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ⓘImportant traits for EscapeDebug<'a>fn clone(&self) -> EscapeDebug<'a>
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impl<'a> Clone for Lines<'a>
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impl<'a> Clone for core_futures_tls::str::EscapeUnicode<'a>
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ⓘImportant traits for EscapeUnicode<'a>fn clone(&self) -> EscapeUnicode<'a>
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impl<'a> Clone for EncodeUtf16<'a>
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ⓘImportant traits for EncodeUtf16<'a>fn clone(&self) -> EncodeUtf16<'a>
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impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>
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fn clone(&self) -> CharSliceSearcher<'a, 'b>
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impl<'a, 'b> Clone for StrSearcher<'a, 'b>
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fn clone(&self) -> StrSearcher<'a, 'b>
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impl<'a, F> Clone for CharPredicateSearcher<'a, F> where
F: Clone + FnMut(char) -> bool,
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F: Clone + FnMut(char) -> bool,
fn clone(&self) -> CharPredicateSearcher<'a, F>
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impl<'a, P> Clone for MatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
ⓘImportant traits for MatchIndices<'a, P>fn clone(&self) -> MatchIndices<'a, P>
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impl<'a, P> Clone for Matches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, P> Clone for RMatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
ⓘImportant traits for RMatchIndices<'a, P>fn clone(&self) -> RMatchIndices<'a, P>
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impl<'a, P> Clone for RMatches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, P> Clone for core_futures_tls::str::RSplit<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, P> Clone for RSplitN<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, P> Clone for RSplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
ⓘImportant traits for RSplitTerminator<'a, P>fn clone(&self) -> RSplitTerminator<'a, P>
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impl<'a, P> Clone for core_futures_tls::str::Split<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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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,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, P> Clone for SplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
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P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
ⓘImportant traits for SplitTerminator<'a, P>fn clone(&self) -> SplitTerminator<'a, P>
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impl<'a, T> Clone for RChunksExact<'a, T>
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ⓘImportant traits for RChunksExact<'a, T>fn clone(&self) -> RChunksExact<'a, T>
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impl<'a, T, P> Clone for core_futures_tls::slice::RSplit<'a, T, P> where
P: Clone + FnMut(&T) -> bool,
T: 'a + Clone,
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P: Clone + FnMut(&T) -> bool,
T: 'a + Clone,
impl<'f> Clone for VaListImpl<'f>
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fn clone(&self) -> VaListImpl<'f>
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impl<A> Clone for Repeat<A> where
A: Clone,
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A: Clone,
impl<A> Clone for core_futures_tls::option::IntoIter<A> where
A: Clone,
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A: Clone,
impl<A, B> Clone for Chain<A, B> where
A: Clone,
B: Clone,
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A: Clone,
B: Clone,
impl<A, B> Clone for Zip<A, B> where
A: Clone,
B: Clone,
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A: Clone,
B: Clone,
impl<F> Clone for FromFn<F> where
F: Clone,
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F: Clone,
impl<F> Clone for OnceWith<F> where
F: Clone,
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F: Clone,
impl<F> Clone for RepeatWith<F> where
F: Clone,
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F: Clone,
ⓘImportant traits for RepeatWith<F>fn clone(&self) -> RepeatWith<F>
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impl<H> Clone for BuildHasherDefault<H>
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fn clone(&self) -> BuildHasherDefault<H>
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impl<I> Clone for DecodeUtf16<I> where
I: Clone + Iterator<Item = u16>,
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I: Clone + Iterator<Item = u16>,
ⓘImportant traits for DecodeUtf16<I>fn clone(&self) -> DecodeUtf16<I>
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impl<I> Clone for Cloned<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Copied<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Cycle<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Enumerate<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Fuse<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Peekable<I> where
I: Clone + Iterator,
<I as Iterator>::Item: Clone,
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I: Clone + Iterator,
<I as Iterator>::Item: Clone,
impl<I> Clone for Skip<I> where
I: Clone,
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I: Clone,
impl<I> Clone for StepBy<I> where
I: Clone,
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I: Clone,
impl<I> Clone for Take<I> where
I: Clone,
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I: Clone,
impl<I, F> Clone for FilterMap<I, F> where
F: Clone,
I: Clone,
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F: Clone,
I: Clone,
impl<I, F> Clone for Inspect<I, F> where
F: Clone,
I: Clone,
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F: Clone,
I: Clone,
impl<I, F> Clone for Map<I, F> where
F: Clone,
I: Clone,
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F: Clone,
I: Clone,
impl<I, P> Clone for Filter<I, P> where
I: Clone,
P: Clone,
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I: Clone,
P: Clone,
impl<I, P> Clone for SkipWhile<I, P> where
I: Clone,
P: Clone,
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I: Clone,
P: Clone,
impl<I, P> Clone for TakeWhile<I, P> where
I: Clone,
P: Clone,
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I: Clone,
P: Clone,
impl<I, St, F> Clone for Scan<I, St, F> where
F: Clone,
I: Clone,
St: Clone,
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F: Clone,
I: Clone,
St: Clone,
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,
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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<I, U, F> Clone for FlatMap<I, U, F> where
F: Clone,
I: Clone,
U: Clone + IntoIterator,
<U as IntoIterator>::IntoIter: Clone,
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F: Clone,
I: Clone,
U: Clone + IntoIterator,
<U as IntoIterator>::IntoIter: Clone,
impl<Idx> Clone for Range<Idx> where
Idx: Clone,
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Idx: Clone,
impl<Idx> Clone for RangeFrom<Idx> where
Idx: Clone,
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Idx: Clone,
impl<Idx> Clone for RangeInclusive<Idx> where
Idx: Clone,
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Idx: Clone,
ⓘImportant traits for RangeInclusive<A>fn clone(&self) -> RangeInclusive<Idx>
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impl<Idx> Clone for RangeTo<Idx> where
Idx: Clone,
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Idx: Clone,
impl<Idx> Clone for RangeToInclusive<Idx> where
Idx: Clone,
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Idx: Clone,
fn clone(&self) -> RangeToInclusive<Idx>
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impl<P> Clone for Pin<P> where
P: Clone,
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P: Clone,
impl<T> Clone for Discriminant<T>
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fn clone(&self) -> Discriminant<T>
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impl<T> Clone for Empty<T>
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impl<T> Clone for *const T where
T: ?Sized,
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T: ?Sized,
impl<T> Clone for *mut T where
T: ?Sized,
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T: ?Sized,
impl<T> Clone for Bound<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Option<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Poll<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Cell<T> where
T: Copy,
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T: Copy,
impl<T> Clone for RefCell<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Reverse<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Once<T> where
T: Clone,
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T: Clone,
impl<T> Clone for Rev<T> where
T: Clone,
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T: Clone,
impl<T> Clone for PhantomData<T> where
T: ?Sized,
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T: ?Sized,
fn clone(&self) -> PhantomData<T>
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impl<T> Clone for ManuallyDrop<T> where
T: Clone + ?Sized,
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T: Clone + ?Sized,
fn clone(&self) -> ManuallyDrop<T>
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impl<T> Clone for Wrapping<T> where
T: Clone,
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T: Clone,
impl<T> Clone for NonNull<T> where
T: ?Sized,
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T: ?Sized,
impl<T> Clone for core_futures_tls::result::IntoIter<T> where
T: Clone,
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T: Clone,
impl<T> Clone for MaybeUninit<T> where
T: Copy,
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T: Copy,
fn clone(&self) -> MaybeUninit<T>
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impl<T, E> Clone for Result<T, E> where
E: Clone,
T: Clone,
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E: Clone,
T: Clone,
impl<T, F> Clone for Successors<T, F> where
F: Clone,
T: Clone,
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F: Clone,
T: Clone,
ⓘImportant traits for Successors<T, F>fn clone(&self) -> Successors<T, F>
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impl<Y, R> Clone for GeneratorState<Y, R> where
R: Clone,
Y: Clone,
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R: Clone,
Y: Clone,