Trait frame_support::dispatch::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.

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 {}

Trait frame_support::dispatch::Eq

Derivable

How can I implement Eq?

Implementations on Foreign Types

impl Eq for Shutdown

impl Eq for IntoStringError

impl Eq for BacktraceStatus

impl Eq for UCred

impl Eq for ErrorKind

impl Eq for StripPrefixError

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

impl Eq for AddrParseError

impl Eq for NulError

impl Eq for Permissions

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

impl Eq for SocketAddrV4

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

impl Eq for FromBytesWithNulError

impl Eq for CStr

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

impl Eq for RecvError

impl Eq for FileType

impl Eq for OsStr

impl Eq for Ipv6MulticastScope

impl Eq for SeekFrom

impl Eq for TryRecvError

impl Eq for CString

impl Eq for ExitStatusError

impl Eq for FromVecWithNulError

impl Eq for SystemTime

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

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

impl Eq for ThreadId

impl Eq for Instant

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

impl<'_> Eq for Components<'_>

impl Eq for VarError

impl Eq for IpAddr

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

impl Eq for SocketAddr

impl Eq for Ipv6Addr

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

impl Eq for OsString

impl Eq for Path

impl Eq for PathBuf

impl Eq for Ipv4Addr

impl Eq for Output

impl Eq for RecvTimeoutError

impl Eq for SocketAddrV6

impl Eq for AccessError

impl Eq for WaitTimeoutResult

impl Eq for ExitStatus

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

impl Eq for ()

impl<Ret, A> Eq for fn(A) -> Ret

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Eq for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Eq for extern "C" fn(A, B, C, D, E, F, G, H, I, J, K, ...) -> Ret

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

impl<A, B, C, D, E, F, G> Eq for (A, B, C, D, E, F, G) where A: Eq, B: Eq, C: Eq, D: Eq, E: Eq, F: Eq, G: Eq + ?Sized,

impl Eq for usize

impl<Ret, A, B, C, D, E, F> Eq for unsafe extern "C" fn(A, B, C, D, E, F, ...) -> Ret

impl<Ret, A, B, C> Eq for extern "C" fn(A, B, C, ...) -> Ret

impl<Ret, A> Eq for unsafe extern "C" fn(A, ...) -> Ret

impl<Ret, A, B> Eq for unsafe extern "C" fn(A, B) -> Ret

impl<Ret, A, B, C, D> Eq for unsafe extern "C" fn(A, B, C, D) -> Ret

impl<Ret, A, B, C, D, E, F, G, H, I, J, K, L> Eq for unsafe fn(A, B, C, D, E, F, G, H, I, J, K, L) -> Ret

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

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

impl<Ret> Eq for extern "C" fn() -> Ret

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

impl<Ret, A, B, C, D, E, F> Eq for fn(A, B, C, D, E, F) -> Ret

impl<Ret, A, B, C, D, E, F, G> Eq for unsafe extern "C" fn(A, B, C, D, E, F, G, ...) -> Ret

impl Eq for NonZeroI64

impl<H> Eq for BuildHasherDefault<H>

impl<Ret, A, B, C, D, E, F, G, H, I, J> Eq for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J) -> Ret

impl Eq for TryFromIntError

impl Eq for NonZeroU128

impl Eq for bool

impl<Ret, A, B, C, D, E, F, G, H, I, J, K> Eq for unsafe extern "C" fn(A, B, C, D, E, F, G, H, I, J, K) -> Ret

impl Eq for Which

How can I implement `Eq`?

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

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

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

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

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

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

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

impl<A, B, C, D, E, F, G> Eq for (A, B, C, D, E, F, G) where
A: Eq,
B: Eq,
C: Eq,
D: Eq,
E: Eq,
F: Eq,
G: Eq + ?Sized,

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

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

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

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

impl<A, B, C, D, E, F, G, H, I, J> Eq for (A, B, C, D, E, F, G, H, I, J) where
A: Eq,
B: Eq,
C: Eq,
D: Eq,
E: Eq,
F: Eq,
G: Eq,
H: Eq,
I: Eq,
J: Eq + ?Sized,

impl<A, B, C> Eq for (A, B, C) where
A: Eq,
B: Eq,
C: Eq + ?Sized,

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

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

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

impl<A, B, C, D, E, F, G, H, I, J, K> Eq for (A, B, C, D, E, F, G, H, I, J, K) where
A: Eq,
B: Eq,
C: Eq,
D: Eq,
E: Eq,
F: Eq,
G: Eq,
H: Eq,
I: Eq,
J: Eq,
K: Eq + ?Sized,

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

impl<A, B, C, D, E, F> Eq for (A, B, C, D, E, F) where
A: Eq,
B: Eq,
C: Eq,
D: Eq,
E: Eq,
F: Eq + ?Sized,

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

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

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

impl<'_, A> Eq for &'_ A where
A: Eq + ?Sized,

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