Trait 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.

Trait EqCopy item path

§Derivable

§How can I implement Eq?

Object Safety§

Implementors§

impl Eq for TryReserveErrorKind

impl Eq for AsciiChar

impl Eq for core::cmp::Ordering

impl Eq for Infallible

impl Eq for core::fmt::Alignment

impl Eq for IpAddr

impl Eq for Ipv6MulticastScope

impl Eq for SocketAddr

impl Eq for FpCategory

impl Eq for IntErrorKind

impl Eq for core::sync::atomic::Ordering

impl Eq for BacktraceStatus

impl Eq for VarError

impl Eq for SeekFrom

impl Eq for std::io::error::ErrorKind

impl Eq for Shutdown

impl Eq for BacktraceStyle

impl Eq for RecvTimeoutError

impl Eq for TryRecvError

impl Eq for base64::alphabet::ParseAlphabetError

impl Eq for base64::alphabet::ParseAlphabetError

impl Eq for base64::decode::DecodeError

impl Eq for base64::decode::DecodeError

impl Eq for base64::decode::DecodeSliceError

impl Eq for base64::decode::DecodeSliceError

impl Eq for base64::encode::EncodeSliceError

impl Eq for base64::encode::EncodeSliceError

impl Eq for base64::engine::DecodePaddingMode

impl Eq for base64::engine::DecodePaddingMode

impl Eq for borsh::nostd_io::ErrorKind

impl Eq for byte_slice_cast::Error

impl Eq for ibc_proto::cosmos::gov::v1::ProposalStatus

impl Eq for ibc_proto::cosmos::gov::v1::VoteOption

impl Eq for ibc_proto::cosmos::gov::v1beta1::ProposalStatus

impl Eq for ibc_proto::cosmos::gov::v1beta1::VoteOption

impl Eq for AuthorizationType

impl Eq for BondStatus

impl Eq for Infraction

impl Eq for ibc_proto::cosmos::staking::v1beta1::InfractionType

impl Eq for SignMode

impl Eq for BroadcastMode

impl Eq for OrderBy

impl Eq for Edition

impl Eq for VerificationState

impl Eq for EnumType

impl Eq for FieldPresence

impl Eq for JsonFormat

impl Eq for MessageEncoding

impl Eq for RepeatedFieldEncoding

impl Eq for Utf8Validation

impl Eq for Label

impl Eq for ibc_proto::google::protobuf::field_descriptor_proto::Type

impl Eq for CType

impl Eq for JsType

impl Eq for OptionRetention

impl Eq for OptionTargetType

impl Eq for OptimizeMode

impl Eq for Semantic

impl Eq for IdempotencyLevel

impl Eq for ibc_proto::ibc::applications::interchain_accounts::v1::Type

impl Eq for Order

impl Eq for ResponseResultType

impl Eq for ibc_proto::ibc::core::channel::v1::State

impl Eq for ibc_proto::ibc::core::connection::v1::State

impl Eq for ConsumerPacketDataType

impl Eq for ibc_proto::interchain_security::ccv::v1::InfractionType

impl Eq for HashOp

impl Eq for LengthOp

impl Eq for MetaForm

impl Eq for PortableForm

impl Eq for TypeDefPrimitive

impl Eq for PathError

impl Eq for InstanceType

impl Eq for Category

impl Eq for Value

Trait Eq

§How can I implement `Eq`?