Trait Eq

pub trait Eq: PartialEq { }

Trait for comparisons corresponding to equivalence relations.

The primary difference to PartialEq is the additional requirement for reflexivity. A type that implements PartialEq guarantees that for all a, b and c:

• symmetric: a == b implies b == a and a != b implies !(a == b)
• transitive: a == b and b == c implies a == c

Eq, which builds on top of PartialEq also implies:

• reflexive: a == a

This property cannot be checked by the compiler, and therefore Eq is a trait without 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.

Floating point types such as f32 and f64 implement only PartialEq but not Eq because NaN != NaN.

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 extra 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 {}

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Eq for IpAddr

impl Eq for SocketAddr

impl Eq for kvarn_async::prelude::fmt::Alignment

impl Eq for ErrorKind

impl Eq for SeekFrom

impl Eq for Ipv6MulticastScope

impl Eq for Shutdown

impl Eq for CacheControlError

impl Eq for RequestParseStage

impl Eq for SanitizeError

impl Eq for AsciiChar

impl Eq for Infallible

impl Eq for FpCategory

impl Eq for IntErrorKind

impl Eq for SearchStep

impl Eq for kvarn_async::prelude::compact_str::core::sync::atomic::Ordering

impl Eq for kvarn_async::prelude::compact_str::core::cmp::Ordering

impl Eq for TryReserveErrorKind

impl Eq for BacktraceStatus

impl Eq for VarError

impl Eq for BacktraceStyle

impl Eq for RecvTimeoutError

impl Eq for std::sync::mpsc::TryRecvError

impl Eq for Level

impl Eq for LevelFilter

impl Eq for bool

impl Eq for char

impl Eq for i8

impl Eq for i16

impl Eq for i32

impl Eq for i64

impl Eq for i128

impl Eq for isize

impl Eq for !

impl Eq for str

impl Eq for u8

impl Eq for u16

impl Eq for u32

impl Eq for u64

impl Eq for u128

impl Eq for ()

impl Eq for usize

impl Eq for Error

impl Eq for AddrParseError

impl Eq for Ipv4Addr

impl Eq for Ipv6Addr

impl Eq for SocketAddrV4

impl Eq for SocketAddrV6

impl Eq for CriticalRequestComponents

impl Eq for ParseBoolError

impl Eq for Utf8Error

impl Eq for Bytes

impl Eq for BytesMut

impl Eq for CompactString

impl Eq for Duration

impl Eq for HeaderName

impl Eq for HeaderValue

impl Eq for kvarn_async::prelude::Instant

impl Eq for Method

impl Eq for Path

impl Eq for PathBuf

impl Eq for StatusCode

impl Eq for Uri

impl Eq for Version

impl Eq for Authority

impl Eq for PathAndQuery

impl Eq for Scheme

impl Eq for AllocError

impl Eq for Layout

impl Eq for LayoutError

impl Eq for TypeId

impl Eq for CpuidResult

impl Eq for CharTryFromError

impl Eq for DecodeUtf16Error

impl Eq for ParseCharError

impl Eq for TryFromCharError

impl Eq for CStr

impl Eq for FromBytesUntilNulError

impl Eq for FromBytesWithNulError

impl Eq for PhantomPinned

impl Eq for Assume

impl Eq for ParseFloatError

impl Eq for ParseIntError

impl Eq for TryFromIntError

impl Eq for kvarn_async::prelude::compact_str::core::ptr::Alignment

impl Eq for RangeFull

impl Eq for TryFromFloatSecsError

impl Eq for UnorderedKeyError

impl Eq for TryReserveError

impl Eq for CString

impl Eq for FromVecWithNulError

impl Eq for IntoStringError

impl Eq for NulError

impl Eq for FromUtf8Error

impl Eq for String

impl Eq for OsStr

impl Eq for OsString

impl Eq for FileType

impl Eq for Permissions

impl Eq for std::os::unix::net::ucred::UCred

impl Eq for Components<'_>

impl Eq for StripPrefixError

impl Eq for ExitStatus

impl Eq for ExitStatusError

impl Eq for Output

impl Eq for std::sync::condvar::WaitTimeoutResult

impl Eq for std::sync::mpsc::RecvError

impl Eq for AccessError

impl Eq for ThreadId

impl Eq for SystemTime

impl Eq for ParseLevelError

impl Eq for Domain

impl Eq for Elapsed

impl Eq for FilterOp

impl Eq for Instant

impl Eq for Interest

impl Eq for Interest

impl Eq for MissedTickBehavior

impl Eq for OnceState

impl Eq for ParkResult

impl Eq for ParkToken

impl Eq for Protocol

impl Eq for Ready

impl Eq for RecvError

impl Eq for RecvError

impl Eq for RecvFlags

impl Eq for RequeueOp

impl Eq for RuntimeFlavor

impl Eq for SockAddr

impl Eq for Token

impl Eq for TryAcquireError

impl Eq for TryRecvError

impl Eq for TryRecvError

impl Eq for TryRecvError

impl Eq for Type

impl Eq for UCred

impl Eq for UnparkResult

impl Eq for UnparkToken

impl Eq for WaitTimeoutResult

impl<'a> Eq for Utf8Pattern<'a>

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

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

impl<'a> Eq for Query<'a>

impl<'a> Eq for QueryPair<'a>

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

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

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

impl<'a> Eq for Metadata<'a>

impl<'a> Eq for MetadataBuilder<'a>

impl<A> Eq for &A

where A: Eq + ?Sized,

impl<A> Eq for &mut A

where A: Eq + ?Sized,

impl<A> Eq for SmallVec<A>

where A: Array, <A as Array>::Item: Eq,

impl<B> Eq for Cow<'_, B>

where B: Eq + ToOwned + ?Sized,

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

where B: Eq, C: Eq,

impl<Dyn> Eq for DynMetadata<Dyn>

where Dyn: ?Sized,

impl<F> Eq for F

where F: FnPtr,

impl<H> Eq for BuildHasherDefault<H>

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::legacy::Range<Idx>

where Idx: Eq,

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::legacy::RangeFrom<Idx>

where Idx: Eq,

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::legacy::RangeInclusive<Idx>

where Idx: Eq,

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::Range<Idx>

where Idx: Eq,

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::RangeFrom<Idx>

where Idx: Eq,

impl<Idx> Eq for kvarn_async::prelude::compact_str::core::range::RangeInclusive<Idx>

where Idx: Eq,

impl<Idx> Eq for RangeTo<Idx>

where Idx: Eq,

impl<Idx> Eq for RangeToInclusive<Idx>

where Idx: Eq,

impl<K, V, A> Eq for BTreeMap<K, V, A>

where K: Eq, V: Eq, A: Allocator + Clone,

impl<K, V, S> Eq for HashMap<K, V, S>

where K: Eq + Hash, V: Eq, S: BuildHasher,

impl<Ptr> Eq for Pin<Ptr>

where Ptr: Deref, <Ptr as Deref>::Target: Eq,

impl<T> Eq for Option<T>

where T: Eq,

impl<T> Eq for Bound<T>

where T: Eq,

impl<T> Eq for Poll<T>

where T: Eq,

impl<T> Eq for std::sync::mpmc::error::SendTimeoutError<T>

where T: Eq,

impl<T> Eq for std::sync::mpsc::TrySendError<T>

where T: Eq,

impl<T> Eq for *const T

where T: ?Sized,

impl<T> Eq for *mut T

where T: ?Sized,

impl<T> Eq for [T]

where T: Eq,

impl<T> Eq for (T₁, T₂, …, Tₙ)

where T: Eq + ?Sized,

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

impl<T> Eq for Cursor<T>

where T: Eq,

impl<T> Eq for HeaderMap<T>

where T: Eq,

impl<T> Eq for Cell<T>

where T: Eq + Copy,

impl<T> Eq for kvarn_async::prelude::compact_str::core::cell::OnceCell<T>

where T: Eq,

impl<T> Eq for RefCell<T>

where T: Eq + ?Sized,

impl<T> Eq for PhantomData<T>

where T: ?Sized,

impl<T> Eq for Discriminant<T>

impl<T> Eq for ManuallyDrop<T>

where T: Eq + ?Sized,

impl<T> Eq for NonZero<T>

where T: ZeroablePrimitive + Eq,

impl<T> Eq for Saturating<T>

where T: Eq,

impl<T> Eq for Wrapping<T>

where T: Eq,

impl<T> Eq for NonNull<T>

where T: ?Sized,

impl<T> Eq for std::sync::mpsc::SendError<T>

where T: Eq,

impl<T> Eq for OnceLock<T>

where T: Eq,

impl<T> Eq for Reverse<T>

where T: Eq,

impl<T> Eq for OnceCell<T>

where T: Eq,

impl<T> Eq for SendError<T>

where T: Eq,

impl<T> Eq for SendError<T>

where T: Eq,

impl<T> Eq for SendTimeoutError<T>

where T: Eq,

impl<T> Eq for SetError<T>

where T: Eq,

impl<T> Eq for TrySendError<T>

where T: Eq,

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

where T: Eq + ?Sized, A: Allocator,

impl<T, A> Eq for Box<T, A>

where T: Eq + ?Sized, A: Allocator,

impl<T, A> Eq for BTreeSet<T, A>

where T: Eq, A: Allocator + Clone,

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

where T: Eq, A: Allocator,

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

where T: Eq, A: Allocator,

impl<T, A> Eq for Rc<T, A>

where T: Eq + ?Sized, A: Allocator,

impl<T, A> Eq for Vec<T, A>

where T: Eq, A: Allocator,

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

where T: Eq, E: Eq,

impl<T, S> Eq for HashSet<T, S>

where T: Eq + Hash, S: BuildHasher,

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

where T: