Trait serde::lib::core::prelude::rust_2021::Eq

1.0.0 · source ·
pub trait Eq: PartialEq<Self> { }
Expand description

Trait for equality comparisons which are equivalence relations.

This means, that in addition to a == b and a != b being strict inverses, the equality must be (for all a, b and c):

  • reflexive: a == a;
  • symmetric: a == b implies b == a; and
  • transitive: a == b and b == c implies a == c.

This property cannot be checked by the compiler, and therefore Eq implies PartialEq, and has no extra methods.

Violating this property is a logic error. The behavior resulting from a logic error is not specified, but users of the trait must ensure that such logic errors do not result in undefined behavior. This means that unsafe code must not rely on the correctness of these methods.

Derivable

This trait can be used with #[derive]. When derived, because Eq has no extra methods, it is only informing the compiler that this is an equivalence relation rather than a partial equivalence relation. Note that the derive strategy requires all fields are Eq, which isn’t always desired.

How can I implement Eq?

If you cannot use the derive strategy, specify that your type implements Eq, which has no methods:

enum BookFormat { Paperback, Hardback, Ebook }
struct Book {
    isbn: i32,
    format: BookFormat,
}
impl PartialEq for Book {
    fn eq(&self, other: &Self) -> bool {
        self.isbn == other.isbn
    }
}
impl Eq for Book {}

Implementors§

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impl Eq for serde::lib::cmp::Ordering

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impl Eq for Infallible

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impl Eq for serde::lib::Ordering

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impl Eq for serde::lib::fmt::Alignment

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impl Eq for IpAddr

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impl Eq for Ipv6MulticastScope

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impl Eq for Shutdown

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impl Eq for SocketAddr

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impl Eq for FpCategory

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impl Eq for IntErrorKind

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impl Eq for SearchStep

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impl Eq for AsciiChar

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impl Eq for BacktraceStatus

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impl Eq for TryReserveErrorKind

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impl Eq for VarError

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impl Eq for ErrorKind

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impl Eq for SeekFrom

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impl Eq for BacktraceStyle

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impl Eq for Which

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impl Eq for RecvTimeoutError

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impl Eq for TryRecvError

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impl Eq for bool

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impl Eq for char

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impl Eq for i8

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impl Eq for i16

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impl Eq for i32

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impl Eq for i64

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impl Eq for i128

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impl Eq for isize

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impl Eq for !

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impl Eq for str

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impl Eq for u8

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impl Eq for u16

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impl Eq for u32

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impl Eq for u64

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impl Eq for u128

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impl Eq for ()

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impl Eq for usize

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impl Eq for Error

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impl Eq for PhantomPinned

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impl Eq for Assume

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impl Eq for AddrParseError

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impl Eq for Ipv4Addr

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impl Eq for Ipv6Addr

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impl Eq for SocketAddrV4

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impl Eq for SocketAddrV6

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impl Eq for NonZeroI8

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impl Eq for NonZeroI16

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impl Eq for NonZeroI32

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impl Eq for NonZeroI64

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impl Eq for NonZeroI128

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impl Eq for NonZeroIsize

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impl Eq for NonZeroU8

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impl Eq for NonZeroU16

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impl Eq for NonZeroU32

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impl Eq for NonZeroU64

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impl Eq for NonZeroU128

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impl Eq for NonZeroUsize

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impl Eq for ParseFloatError

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impl Eq for ParseIntError

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impl Eq for TryFromIntError

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impl Eq for serde::lib::ptr::Alignment

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impl Eq for ParseBoolError

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impl Eq for Utf8Error

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impl Eq for CStr

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impl Eq for CString

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impl Eq for Duration

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impl Eq for OsStr

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impl Eq for OsString

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impl Eq for Path

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impl Eq for PathBuf

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impl Eq for String

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impl Eq for SystemTime

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impl Eq for AllocError

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impl Eq for Layout

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impl Eq for LayoutError

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impl Eq for TypeId

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impl Eq for CpuidResult

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impl Eq for CharTryFromError

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impl Eq for DecodeUtf16Error

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impl Eq for ParseCharError

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impl Eq for TryFromCharError

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impl Eq for TryReserveError

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impl Eq for FromBytesUntilNulError

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impl Eq for FromBytesWithNulError

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impl Eq for FromVecWithNulError

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impl Eq for IntoStringError

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impl Eq for NulError

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impl Eq for FileType

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impl Eq for Permissions

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impl Eq for RangeFull

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impl Eq for UCred

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impl Eq for Components<'_>

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impl Eq for StripPrefixError

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impl Eq for ExitStatus

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impl Eq for ExitStatusError

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impl Eq for Output

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impl Eq for FromUtf8Error

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impl Eq for RecvError

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impl Eq for WaitTimeoutResult

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impl Eq for AccessError

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impl Eq for ThreadId

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impl Eq for Instant

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impl Eq for TryFromFloatSecsError

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impl<'a> Eq for Component<'a>

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impl<'a> Eq for Prefix<'a>

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impl<'a> Eq for Utf8Chunk<'a>

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impl<'a> Eq for Location<'a>

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impl<'a> Eq for PrefixComponent<'a>

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impl<A> Eq for &Awhere A: Eq + ?Sized,

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impl<A> Eq for &mut Awhere A: Eq + ?Sized,

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impl<B> Eq for Cow<'_, B>where B: Eq + ToOwned + ?Sized,

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impl<B, C> Eq for ControlFlow<B, C>where B: Eq, C: Eq,

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impl<Dyn> Eq for DynMetadata<Dyn>where Dyn: ?Sized,

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impl<F> Eq for Fwhere F: FnPtr,

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impl<H> Eq for BuildHasherDefault<H>

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impl<Idx> Eq for Range<Idx>where Idx: Eq,

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impl<Idx> Eq for RangeFrom<Idx>where Idx: Eq,

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impl<Idx> Eq for RangeInclusive<Idx>where Idx: Eq,

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impl<Idx> Eq for RangeTo<Idx>where Idx: Eq,

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impl<Idx> Eq for RangeToInclusive<Idx>where Idx: Eq,

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impl<K, V, A> Eq for BTreeMap<K, V, A>where K: Eq, V: Eq, A: Allocator + Clone,

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impl<K, V, S> Eq for HashMap<K, V, S>where K: Eq + Hash, V: Eq, S: BuildHasher,

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impl<P> Eq for Pin<P>where P: Deref, <P as Deref>::Target: Eq,

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impl<T> Eq for Bound<T>where T: Eq,

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impl<T> Eq for Option<T>where T: Eq,

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impl<T> Eq for TrySendError<T>where T: Eq,

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impl<T> Eq for Poll<T>where T: Eq,

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impl<T> Eq for *const Twhere T: ?Sized,

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impl<T> Eq for *mut Twhere T: ?Sized,

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impl<T> Eq for [T]where T: Eq,

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impl<T> Eq for (T₁, T₂, …, Tₙ)where T: Eq + ?Sized,

This trait is implemented for tuples up to twelve items long.

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impl<T> Eq for Discriminant<T>

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impl<T> Eq for ManuallyDrop<T>where T: Eq + ?Sized,

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impl<T> Eq for NonNull<T>where T: ?Sized,

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impl<T> Eq for Cell<T>where T: Eq + Copy,

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impl<T> Eq for PhantomData<T>where T: ?Sized,

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impl<T> Eq for RefCell<T>where T: Eq + ?Sized,

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impl<T> Eq for Reverse<T>where T: Eq,

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impl<T> Eq for Saturating<T>where T: Eq,

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impl<T> Eq for Wrapping<T>where T: Eq,

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impl<T> Eq for OnceCell<T>where T: Eq,

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impl<T> Eq for Cursor<T>where T: Eq,

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impl<T> Eq for SendError<T>where T: Eq,

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impl<T> Eq for OnceLock<T>where T: Eq,

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impl<T, A> Eq for Arc<T, A>where T: Eq + ?Sized, A: Allocator,

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impl<T, A> Eq for BTreeSet<T, A>where T: Eq, A: Allocator + Clone,

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impl<T, A> Eq for Box<T, A>where T: Eq + ?Sized, A: Allocator,

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impl<T, A> Eq for LinkedList<T, A>where T: Eq, A: Allocator,

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impl<T, A> Eq for Rc<T, A>where T: Eq + ?Sized, A: Allocator,

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impl<T, A> Eq for Vec<T, A>where T: Eq, A: Allocator,

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impl<T, A> Eq for VecDeque<T, A>where T: Eq, A: Allocator,

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impl<T, E> Eq for Result<T, E>where T: Eq, E: Eq,

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impl<T, S> Eq for HashSet<T, S>where T: Eq + Hash, S: BuildHasher,

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impl<T, const N: usize> Eq for [T; N]where T: Eq,

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impl<T, const N: usize> Eq for Simd<T, N>where LaneCount<N>: SupportedLaneCount, T: SimdElement + Eq,

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impl<Y, R> Eq for GeneratorState<Y, R>where Y: Eq, R: Eq,