Struct WithCachedTypeInfo

pub struct WithCachedTypeInfo<T> {
    pub internee: T,
    pub stable_hash: Fingerprint,
    pub flags: TypeFlags,
    pub outer_exclusive_binder: DebruijnIndex,
}

A helper type that you can wrap round your own type in order to automatically cache the stable hash, type flags and debruijn index on creation and not recompute it whenever the information is needed. This is only done in incremental mode. You can also opt out of caching by using StableHash::ZERO for the hash, in which case the hash gets computed each time. This is useful if you have values that you intern but never (can?) use for stable hashing.

Fields

internee: T

stable_hash: Fingerprint

flags: TypeFlags

This field provides fast access to information that is also contained in kind.

This field shouldn’t be used directly and may be removed in the future. Use Ty::flags() instead.

outer_exclusive_binder: DebruijnIndex

This field provides fast access to information that is also contained in kind.

This is a kind of confusing thing: it stores the smallest binder such that

(a) the binder itself captures nothing but (b) all the late-bound things within the type are captured by some sub-binder.

So, for a type without any late-bound things, like u32, this will be innermost, because that is the innermost binder that captures nothing. But for a type &'D u32, where 'D is a late-bound region with De Bruijn index D, this would be D + 1 – the binder itself does not capture D, but D is captured by an inner binder.

We call this concept an “exclusive” binder D because all De Bruijn indices within the type are contained within 0..D (exclusive).

Trait Implementations

impl<T> Clone for WithCachedTypeInfo<T>

where T: Clone,

fn clone(&self) -> WithCachedTypeInfo<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Deref for WithCachedTypeInfo<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.

impl<T> Hash for WithCachedTypeInfo<T>

where T: Hash,

fn hash<H>(&self, s: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T, CTX> HashStable<CTX> for WithCachedTypeInfo<T>

where T: HashStable<CTX>,

fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher<SipHasher128>)

impl<T> Ord for WithCachedTypeInfo<T>

where T: Ord,

fn cmp(&self, other: &WithCachedTypeInfo<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T> PartialEq for WithCachedTypeInfo<T>

where T: PartialEq,

fn eq(&self, other: &WithCachedTypeInfo<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T> PartialOrd for WithCachedTypeInfo<T>

where T: Ord,

fn partial_cmp(&self, other: &WithCachedTypeInfo<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T> Copy for WithCachedTypeInfo<T>

where T: Copy,

impl<T> Eq for WithCachedTypeInfo<T>

where T: Eq,

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.