core::cmp::Eq - Rust
Description: API documentation for the Rust `Eq` trait in crate `core`.
Keywords: rust, rustlang, rust-lang, Eq

# 1.0.0[−][src]Trait core::cmp::Eq

    pub trait Eq: PartialEq<Self> { }

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 `derive`d, 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: &Book) -> bool {
            self.isbn == other.isbn
        }
    }
    impl Eq for Book {}Run

## Implementors

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`impl Eq for !`

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`impl Eq for ()`

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`impl Eq for Ordering`

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`impl Eq for FpCategory`

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`impl Eq for SearchStep`

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`impl Eq for AllocErr`

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`impl Eq for CannotReallocInPlace`

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`impl Eq for Layout`

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`impl Eq for LayoutErr`

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`impl Eq for TypeId`

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`impl Eq for CpuidResult`

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`impl Eq for CharTryFromError`

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`impl Eq for DecodeUtf16Error`

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`impl Eq for ParseCharError`

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`impl Eq for UnicodeVersion`

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`impl Eq for Error`

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`impl Eq for Pinned`

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`impl Eq for NonZeroU128`

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`impl Eq for NonZeroU16`

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`impl Eq for NonZeroU32`

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`impl Eq for NonZeroU64`

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`impl Eq for NonZeroU8`

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`impl Eq for NonZeroUsize`

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`impl Eq for ParseFloatError`

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`impl Eq for ParseIntError`

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`impl Eq for TryFromIntError`

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`impl Eq for RangeFull`

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`impl Eq for NoneError`

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`impl Eq for ParseBoolError`

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`impl Eq for Utf8Error`

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`impl Eq for Duration`

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`impl Eq for bool`

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`impl Eq for char`

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`impl Eq for i8`

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`impl Eq for i16`

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`impl Eq for i32`

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`impl Eq for i64`

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`impl Eq for i128`

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`impl Eq for isize`

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`impl Eq for str`

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`impl Eq for u8`

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`impl Eq for u16`

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`impl Eq for u32`

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`impl Eq for u64`

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`impl Eq for u128`

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`impl Eq for usize`

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`impl<'a> Eq for Utf8LossyChunk<'a>`

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`impl<'a, A: ?Sized> Eq for &'a A where A: Eq,`

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`impl<'a, A: ?Sized> Eq for &'a mut A where A: Eq,`

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

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

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

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

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

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

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

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

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

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

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

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

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`impl<H> Eq for BuildHasherDefault<H>`

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`impl<Idx: Eq> Eq for Range<Idx>`

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`impl<Idx: Eq> Eq for RangeFrom<Idx>`

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`impl<Idx: Eq> Eq for RangeInclusive<Idx>`

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`impl<Idx: Eq> Eq for RangeTo<Idx>`

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`impl<Idx: Eq> Eq for RangeToInclusive<Idx>`

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

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`impl<Ret> Eq for fn() -> Ret`

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

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`impl<Ret> Eq for unsafe fn() -> Ret`

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`impl<Ret, A> Eq for extern "C" fn(_: A) -> Ret`

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

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

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

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

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`impl<Ret, A> Eq for unsafe fn(_: A) -> Ret`

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

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

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`impl<Ret, A, B> Eq for fn(_: A, _: B) -> Ret`

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

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

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`impl<Ret, A, B> Eq for unsafe fn(_: A, _: B) -> Ret`

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

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

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`impl<Ret, A, B, C> Eq for fn(_: A, _: B, _: C) -> Ret`

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

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

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`impl<Ret, A, B, C> Eq for unsafe fn(_: A, _: B, _: C) -> Ret`

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

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

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`impl<Ret, A, B, C, D> Eq for fn(_: A, _: B, _: C, _: D) -> Ret`

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

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

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`impl<Ret, A, B, C, D> Eq for unsafe fn(_: A, _: B, _: C, _: D) -> Ret`

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`impl<Ret, A, B, C, D, E> Eq for extern "C" fn(_: A, _: B, _: C, _: D, _: E) -> Ret`

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`impl<Ret, A, B, C, D, E> Eq for extern "C" fn(_: A, _: B, _: C, _: D, _: E, ...) -> Ret`

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

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

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

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`impl<Ret, A, B, C, D, E> Eq for unsafe fn(_: A, _: B, _: C, _: D, _: E) -> Ret`

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`impl<Ret, A, B, C, D, E, F> Eq for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F) -> Ret`

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

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

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

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

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

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

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

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

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

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

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`impl<Ret, A, B, C, D, E, F, G> Eq for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G) -> Ret`

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`impl<Ret, A, B, C, D, E, F, G, H> Eq for extern "C" fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret`

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

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`impl<Ret, A, B, C, D, E, F, G, H> Eq for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret`

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

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

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`impl<Ret, A, B, C, D, E, F, G, H> Eq for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H) -> Ret`

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

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

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`impl<Ret, A, B, C, D, E, F, G, H, I> Eq for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret`

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

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

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`impl<Ret, A, B, C, D, E, F, G, H, I> Eq for unsafe fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I) -> Ret`

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

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

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`impl<Ret, A, B, C, D, E, F, G, H, I, J> Eq for fn(_: A, _: B, _: C, _: D, _: E, _: F, _: G, _: H, _: I, _: J) -> Ret`

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`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`

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`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`

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

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`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`

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`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`

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

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`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`

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`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`

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

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`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`

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`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`

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

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

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

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`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`

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`impl<T> Eq for Discriminant<T>`

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`impl<T: Eq + Copy> Eq for Cell<T>`

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`impl<T: Eq + ?Sized> Eq for ManuallyDrop<T>`

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`impl<T: Eq> Eq for Bound<T>`

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`impl<T: Eq> Eq for Option<T>`

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`impl<T: Eq> Eq for Poll<T>`

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`impl<T: Eq> Eq for Reverse<T>`

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`impl<T: Eq> Eq for Wrapping<T>`

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`impl<T: Eq> Eq for [T; 0]`

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`impl<T: Eq> Eq for [T; 1]`

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`impl<T: Eq> Eq for [T; 2]`

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`impl<T: Eq> Eq for [T; 3]`

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`impl<T: Eq> Eq for [T; 4]`

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`impl<T: Eq> Eq for [T; 5]`

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`impl<T: Eq> Eq for [T; 6]`

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`impl<T: Eq> Eq for [T; 7]`

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`impl<T: Eq> Eq for [T; 8]`

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`impl<T: Eq> Eq for [T; 9]`

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`impl<T: Eq> Eq for [T; 10]`

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`impl<T: Eq> Eq for [T; 12]`

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`impl<T: Eq> Eq for [T; 13]`

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`impl<T: Eq> Eq for [T; 14]`

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`impl<T: Eq> Eq for [T; 15]`

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`impl<T: Eq> Eq for [T; 16]`

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`impl<T: Eq> Eq for [T; 17]`

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`impl<T: Eq> Eq for [T; 18]`

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`impl<T: Eq> Eq for [T; 19]`

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`impl<T: Eq> Eq for [T; 20]`

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`impl<T: Eq> Eq for [T; 21]`

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`impl<T: Eq> Eq for [T; 22]`

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`impl<T: Eq> Eq for [T; 23]`

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`impl<T: Eq> Eq for [T; 24]`

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`impl<T: Eq> Eq for [T; 25]`

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`impl<T: Eq> Eq for [T; 26]`

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`impl<T: Eq> Eq for [T; 27]`

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`impl<T: Eq> Eq for [T; 28]`

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`impl<T: Eq> Eq for [T; 29]`

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`impl<T: Eq> Eq for [T; 30]`

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`impl<T: Eq> Eq for [T; 31]`

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`impl<T: Eq> Eq for [T; 32]`

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`impl<T: Eq> Eq for [T]`

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`impl<T: Eq, E: Eq> Eq for Result<T, E>`

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`impl<T: ?Sized + Eq> Eq for RefCell<T>`

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`impl<T: ?Sized> Eq for *const T`

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`impl<T: ?Sized> Eq for *mut T`

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`impl<T: ?Sized> Eq for PhantomData<T>`

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`impl<T: ?Sized> Eq for NonNull<T>`

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

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## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g. `str,u8` or `String,struct:Vec,test`)