cs431_homework::test::loom::prelude::v1

Trait Eq

1.0.0 · 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 AhoCorasickKind

impl Eq for aho_corasick::packed::api::MatchKind

impl Eq for aho_corasick::util::error::MatchErrorKind

impl Eq for aho_corasick::util::search::Anchored

impl Eq for aho_corasick::util::search::MatchKind

impl Eq for StartKind

impl Eq for crossbeam_channel::err::RecvTimeoutError

impl Eq for crossbeam_channel::err::TryRecvError

impl Eq for BernoulliError

impl Eq for rand::distr::uniform::Error

impl Eq for rand::distr::weighted::Error

impl Eq for State

impl Eq for regex_automata::util::look::Look

impl Eq for regex_automata::util::search::Anchored

impl Eq for regex_automata::util::search::MatchErrorKind

impl Eq for regex_automata::util::search::MatchKind

impl Eq for AssertionKind

impl Eq for Ast

impl Eq for ClassAsciiKind

impl Eq for ClassPerlKind

impl Eq for ClassSet

impl Eq for ClassSetBinaryOpKind

impl Eq for ClassSetItem

impl Eq for ClassUnicodeKind

impl Eq for ClassUnicodeOpKind

impl Eq for regex_syntax::ast::ErrorKind

impl Eq for Flag

impl Eq for FlagsItemKind

impl Eq for GroupKind

impl Eq for HexLiteralKind

impl Eq for LiteralKind

impl Eq for RepetitionKind

impl Eq for RepetitionRange

impl Eq for SpecialLiteralKind

impl Eq for regex_syntax::error::Error

impl Eq for Class

impl Eq for Dot

impl Eq for regex_syntax::hir::ErrorKind

impl Eq for HirKind

impl Eq for regex_syntax::hir::Look

impl Eq for Utf8Sequence

impl Eq for zerocopy::byteorder::BigEndian

impl Eq for zerocopy::byteorder::LittleEndian

impl Eq for AsciiChar

impl Eq for BacktraceStatus

impl Eq for cs431_homework::test::loom::cmp::Ordering

impl Eq for TryReserveErrorKind

impl Eq for Infallible

impl Eq for VarError

impl Eq for FromBytesWithNulError

impl Eq for cs431_homework::test::loom::fmt::Alignment

impl Eq for DebugAsHex

impl Eq for Sign

impl Eq for cs431_homework::test::loom::io::ErrorKind

impl Eq for SeekFrom

impl Eq for IpAddr

impl Eq for Ipv6MulticastScope

impl Eq for Shutdown

impl Eq for SocketAddr

impl Eq for FpCategory

impl Eq for IntErrorKind

impl Eq for BacktraceStyle

impl Eq for GetDisjointMutError

impl Eq for SearchStep

impl Eq for cs431_homework::test::loom::sync::atomic::Ordering

impl Eq for cs431_homework::test::loom::sync::mpmc::RecvTimeoutError

impl Eq for cs431_homework::test::loom::sync::mpmc::TryRecvError

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

Trait Eq

§How can I implement `Eq`?