wasmtime_environ::__core::prelude::rust_2024

Trait Eq

pub trait Eq: PartialEq { }

🔬This is a nightly-only experimental API. (prelude_2024)

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 {}

Object Safety§

This trait is not object safe.

Trait EqCopy item path

§Derivable

§How can I implement Eq?

Object Safety§

Implementors§

impl Eq for ConstOp

impl Eq for EngineOrModuleTypeIndex

impl Eq for EntityIndex

impl Eq for Trap

impl Eq for VMGcKind

impl Eq for WasmCompositeType

impl Eq for WasmHeapTopType

impl Eq for WasmHeapType

impl Eq for WasmStorageType

impl Eq for WasmValType

impl Eq for LibCall

impl Eq for BlockType

impl Eq for CanonicalOption

impl Eq for ComdatSymbolKind

impl Eq for ComponentExternalKind

impl Eq for ComponentOuterAliasKind

impl Eq for ComponentTypeRef

impl Eq for ComponentValType

impl Eq for CompositeType

impl Eq for Encoding

impl Eq for ExternalKind

impl Eq for FrameKind

impl Eq for HeapType

impl Eq for InstantiationArgKind

impl Eq for wasmtime_environ::wasmparser::Ordering

impl Eq for OuterAliasKind

impl Eq for PrimitiveValType

impl Eq for RelocAddendKind

impl Eq for RelocationType

impl Eq for StorageType

impl Eq for TypeBounds

impl Eq for UnpackedIndex

impl Eq for ValType

impl Eq for ComponentNameKind<'_>

impl Eq for AnyTypeId

impl Eq for ComponentAnyTypeId

impl Eq for ComponentCoreTypeId

impl Eq for AsciiChar

impl Eq for wasmtime_environ::__core::cmp::Ordering

impl Eq for Infallible

impl Eq for wasmtime_environ::__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 SearchStep

impl Eq for wasmtime_environ::__core::sync::atomic::Ordering

impl Eq for TryReserveErrorKind

impl Eq for hashbrown::TryReserveError

impl Eq for AddressSize

impl Eq for object::common::Architecture

impl Eq for object::common::BinaryFormat

impl Eq for ComdatKind

impl Eq for FileFlags

impl Eq for RelocationEncoding

impl Eq for RelocationFlags

impl Eq for RelocationKind

impl Eq for SectionFlags

impl Eq for SectionKind

impl Eq for object::common::SegmentFlags

impl Eq for SubArchitecture

impl Eq for SymbolKind

impl Eq for SymbolScope

impl Eq for object::endian::Endianness

impl Eq for CompressionFormat

impl Eq for FileKind

impl Eq for ObjectKind

impl Eq for RelocationTarget

impl Eq for SymbolSection

impl Eq for Op

impl Eq for CDataModel

impl Eq for Size

impl Eq for ParseError

impl Eq for Aarch64Architecture

Trait Eq

§How can I implement `Eq`?