uniffi::deps::static_assertions::_core::prelude::rust_2024

Trait Eq

1.85.0 · Source

pub trait Eq: PartialEq { }

Expand description

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.

Trait EqCopy item path

§Derivable

§How can I implement Eq?

Dyn Compatibility§

Implementors§

impl Eq for AnsiColor

impl Eq for Color

impl Eq for Action

impl Eq for State

impl Eq for DependencyKind

impl Eq for Applicability

impl Eq for DiagnosticLevel

impl Eq for Edition

impl Eq for Message

impl Eq for Cfg

impl Eq for CfgExpr

impl Eq for Platform

impl Eq for ArgPredicate

impl Eq for ValueHint

impl Eq for ContextKind

impl Eq for ContextValue

impl Eq for clap_builder::error::kind::ErrorKind

impl Eq for ValueSource

impl Eq for clap_builder::util::color::ColorChoice

impl Eq for colorchoice::ColorChoice

impl Eq for StackFrameOffset

impl Eq for UnwindOperation

impl Eq for nom::error::ErrorKind

impl Eq for Needed

impl Eq for Endianness

impl Eq for oneshot_uniffi::errors::RecvTimeoutError

impl Eq for oneshot_uniffi::errors::TryRecvError

impl Eq for plain::error::Error

impl Eq for Endian

impl Eq for Op

impl Eq for Category

impl Eq for Value

impl Eq for Offset

impl Eq for toml::ser::Error

impl Eq for uniffi_bindgen::bindings::kotlin::gen_kotlin::ImportRequirement

impl Eq for uniffi_bindgen::bindings::python::gen_python::ImportRequirement

impl Eq for FfiType

impl Eq for ErrorMetadata

impl Eq for LiteralMetadata

impl Eq for uniffi_meta::Metadata

impl Eq for Radix

impl Eq for UniffiTraitMetadata

impl Eq for ExternalKind

impl Eq for ObjectImpl

impl Eq for uniffi_meta::types::Type

impl Eq for Special

impl Eq for StringifierOrInheritOrStatic

impl Eq for StringifierOrStatic

impl Eq for FloatingPointType

impl Eq for IntegerType

impl Eq for CallbackResult

impl Eq for ForeignExecutorCallbackResult

impl Eq for RustCallStatusCode

impl Eq for RustFuturePoll

impl Eq for RustTaskCallbackCode

impl Eq for TargetLanguage

impl Eq for Level

impl Eq for LevelFilter

impl Eq for AsciiChar

impl Eq for uniffi::deps::static_assertions::_core::cmp::Ordering

impl Eq for Infallible

impl Eq for uniffi::deps::static_assertions::_core::fmt::Alignment

impl Eq for DebugAsHex

impl Eq for Sign

impl Eq for IpAddr

impl Eq for Ipv6MulticastScope

impl Eq for SocketAddr

impl Eq for FpCategory

impl Eq for IntErrorKind

impl Eq for GetManyMutError

impl Eq for SearchStep

impl Eq for uniffi::deps::static_assertions::_core::sync::atomic::Ordering

impl Eq for TryReserveErrorKind

impl Eq for BacktraceStatus

impl Eq for VarError

Trait Eq

§How can I implement `Eq`?