[−][src]Trait rustc_ap_rustc_data_structures::stable_hasher::HashStable

pub trait HashStable<CTX> {
    fn hash_stable<W: StableHasherResult>(
        &self, 
        hcx: &mut CTX, 
        hasher: &mut StableHasher<W>
    );
}

Something that implements HashStable<CTX> can be hashed in a way that is stable across multiple compilation sessions.

Note that HashStable imposes rather more strict requirements than usual hash functions:

  • Stable hashes are sometimes used as identifiers. Therefore they must conform to the corresponding PartialEq implementations:

    • x == y implies hash_stable(x) == hash_stable(y), and
    • x != y implies hash_stable(x) != hash_stable(y).

    That second condition is usually not required for hash functions (e.g. Hash). In practice this means that hash_stable must feed any information into the hasher that a PartialEq comparision takes into account. See #49300 for an example where violating this invariant has caused trouble in the past.

  • hash_stable() must be independent of the current compilation session. E.g. they must not hash memory addresses or other things that are "randomly" assigned per compilation session.

  • hash_stable() must be independent of the host architecture. The StableHasher takes care of endianness and isize/usize platform differences.

Required methods

fn hash_stable<W: StableHasherResult>(
    &self,
    hcx: &mut CTX,
    hasher: &mut StableHasher<W>
)

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Implementations on Foreign Types

impl<CTX> HashStable<CTX> for i8[src]

impl<CTX> HashStable<CTX> for i16[src]

impl<CTX> HashStable<CTX> for i32[src]

impl<CTX> HashStable<CTX> for i64[src]

impl<CTX> HashStable<CTX> for isize[src]

impl<CTX> HashStable<CTX> for u8[src]

impl<CTX> HashStable<CTX> for u16[src]

impl<CTX> HashStable<CTX> for u32[src]

impl<CTX> HashStable<CTX> for u64[src]

impl<CTX> HashStable<CTX> for usize[src]

impl<CTX> HashStable<CTX> for u128[src]

impl<CTX> HashStable<CTX> for i128[src]

impl<CTX> HashStable<CTX> for char[src]

impl<CTX> HashStable<CTX> for ()[src]

impl<CTX> HashStable<CTX> for NonZeroU32[src]

impl<CTX> HashStable<CTX> for f32[src]

impl<CTX> HashStable<CTX> for f64[src]

impl<CTX> HashStable<CTX> for Ordering[src]

impl<T1: HashStable<CTX>, CTX> HashStable<CTX> for (T1,)[src]

impl<T1: HashStable<CTX>, T2: HashStable<CTX>, CTX> HashStable<CTX> for (T1, T2)[src]

impl<T1, T2, T3, CTX> HashStable<CTX> for (T1, T2, T3) where
    T1: HashStable<CTX>,
    T2: HashStable<CTX>,
    T3: HashStable<CTX>, [src]

impl<T1, T2, T3, T4, CTX> HashStable<CTX> for (T1, T2, T3, T4) where
    T1: HashStable<CTX>,
    T2: HashStable<CTX>,
    T3: HashStable<CTX>,
    T4: HashStable<CTX>, [src]

impl<T: HashStable<CTX>, CTX> HashStable<CTX> for [T][src]

impl<T: HashStable<CTX>, CTX> HashStable<CTX> for Vec<T>[src]

impl<K, V, R, CTX> HashStable<CTX> for IndexMap<K, V, R> where
    K: HashStable<CTX> + Eq + Hash,
    V: HashStable<CTX>,
    R: BuildHasher, [src]

impl<K, R, CTX> HashStable<CTX> for IndexSet<K, R> where
    K: HashStable<CTX> + Eq + Hash,
    R: BuildHasher, [src]

impl<A, CTX> HashStable<CTX> for SmallVec<[A; 1]> where
    A: HashStable<CTX>, [src]

impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for Box<T>[src]

impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for Arc<T>[src]

impl<CTX> HashStable<CTX> for str[src]

impl<CTX> HashStable<CTX> for String[src]

impl<CTX> HashStable<CTX> for bool[src]

impl<T, CTX> HashStable<CTX> for Option<T> where
    T: HashStable<CTX>, [src]

impl<T1, T2, CTX> HashStable<CTX> for Result<T1, T2> where
    T1: HashStable<CTX>,
    T2: HashStable<CTX>, [src]

impl<'a, T: ?Sized, CTX> HashStable<CTX> for &'a T where
    T: HashStable<CTX>, [src]

impl<T, CTX> HashStable<CTX> for Discriminant<T>[src]

impl<CTX> HashStable<CTX> for Path[src]

impl<CTX> HashStable<CTX> for PathBuf[src]

impl<K, V, R, HCX> HashStable<HCX> for HashMap<K, V, R> where
    K: ToStableHashKey<HCX> + Eq + Hash,
    V: HashStable<HCX>,
    R: BuildHasher, [src]

impl<K, R, HCX> HashStable<HCX> for HashSet<K, R> where
    K: ToStableHashKey<HCX> + Eq + Hash,
    R: BuildHasher, [src]

impl<K, V, HCX> HashStable<HCX> for BTreeMap<K, V> where
    K: ToStableHashKey<HCX>,
    V: HashStable<HCX>, [src]

impl<K, HCX> HashStable<HCX> for BTreeSet<K> where
    K: ToStableHashKey<HCX>, [src]

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Implementors

impl<CTX> HashStable<CTX> for Fingerprint[src]

impl<CTX, T> HashStable<CTX> for TransitiveRelation<T> where
    T: HashStable<CTX> + Eq + Debug + Clone + Hash, [src]

impl<I: Idx, CTX> HashStable<CTX> for BitSet<I>[src]

impl<I: Idx, T, CTX> HashStable<CTX> for IndexVec<I, T> where
    T: HashStable<CTX>, [src]

impl<R: Idx, C: Idx, CTX> HashStable<CTX> for BitMatrix<R, C>[src]

impl<T> HashStable<T> for Svh[src]

impl<T, HCX> HashStable<HCX> for StableVec<T> where
    T: HashStable<HCX> + ToStableHashKey<HCX>, [src]

impl<T: HashStable<CTX>, CTX> HashStable<CTX> for ThinVec<T>[src]

impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for Rc<T>[src]

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