Trait sp_std::prelude::Eq

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

Trait for comparisons corresponding to equivalence relations.

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

  • reflexive: a == a;
  • symmetric: a == b implies b == a (required by PartialEq as well); and
  • transitive: a == b and b == c implies a == c (required by PartialEq as well).

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.

Implement Eq in addition to PartialEq if it’s guaranteed that PartialEq::eq(a, a) always returns true (reflexivity), in addition to the symmetric and transitive properties already required by PartialEq.

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 {}

Object Safety§

This trait is not object safe.

Implementors§

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impl Eq for sp_std::cmp::Ordering

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impl Eq for Infallible

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impl Eq for sp_std::fmt::Alignment

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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 sp_std::sync::atomic::Ordering

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impl Eq for RecvTimeoutError

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impl Eq for TryRecvError

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impl Eq for TryReserveErrorKind

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impl Eq for AsciiChar

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impl Eq for IpAddr

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impl Eq for Ipv6MulticastScope

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impl Eq for SocketAddr

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impl Eq for BacktraceStatus

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impl Eq for VarError

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impl Eq for SeekFrom

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impl Eq for ErrorKind

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impl Eq for Shutdown

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impl Eq for BacktraceStyle

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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 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 Error

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impl Eq for PhantomPinned

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impl Eq for Assume

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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 RangeFull

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impl Eq for sp_std::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 RecvError

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impl Eq for WaitTimeoutResult

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impl Eq for Duration

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impl Eq for TryFromFloatSecsError

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impl Eq for TryReserveError

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impl Eq for CString

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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 FromUtf8Error

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impl Eq for String

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impl Eq for CharTryFromError

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impl Eq for ParseCharError

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impl Eq for DecodeUtf16Error

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impl Eq for TryFromCharError

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impl Eq for CpuidResult

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impl Eq for CStr

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impl Eq for FromBytesUntilNulError

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impl Eq for FromBytesWithNulError

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impl Eq for Ipv4Addr

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impl Eq for Ipv6Addr

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impl Eq for AddrParseError

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impl Eq for SocketAddrV4

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impl Eq for SocketAddrV6

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impl Eq for OsStr

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impl Eq for OsString

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impl Eq for FileType

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impl Eq for Permissions

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impl Eq for UCred

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impl Eq for Components<'_>

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impl Eq for Path

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impl Eq for PathBuf

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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 AccessError

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impl Eq for ThreadId

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impl Eq for Instant

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impl Eq for SystemTime

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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 &A
where A: Eq + ?Sized,

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impl<A> Eq for &mut A
where 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 F
where 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 TrySendError<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 Poll<T>
where T: Eq,

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

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

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

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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 PhantomData<T>
where T: ?Sized,

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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 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 NonNull<T>
where T: ?Sized,

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

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

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impl<T, A> Eq for VecDeque<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 Arc<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 LinkedList<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>

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