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docs: std:#️⃣:Hash should ensure prefix-free data

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Closes #89429
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pierwill 2021-10-01 12:39:08 -05:00
parent ed937594d3
commit f531b8122e
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10
library/core/src/hash/mod.rs
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@ -153,9 +153,19 @@ mod sip;
/// Thankfully, you won't need to worry about upholding this property when
/// deriving both [`Eq`] and `Hash` with `#[derive(PartialEq, Eq, Hash)]`.
///
/// ## Prefix collisions
///
/// Implementations of `hash` should ensure that the data they
/// pass to the `Hasher` are prefix-free. That is, different concatenations
/// of the same data should not produce the same output.
/// For example, the standard implementation of [`Hash` for `&str`][impl] passes an extra
/// `0xFF` byte to the `Hasher` so that the values `("ab", "c")` and `("a",
/// "bc")` hash differently.
///
/// [`HashMap`]: ../../std/collections/struct.HashMap.html
/// [`HashSet`]: ../../std/collections/struct.HashSet.html
/// [`hash`]: Hash::hash
/// [impl]: ../../std/primitive.str.html#impl-Hash
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_diagnostic_item = "Hash"]
pub trait Hash {