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

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.

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§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§

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impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for WithCachedTypeInfo<PredicateKind<'tcx>>

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = Self> ) -> &'a mut [Self]

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impl<'tcx> ArenaAllocatable<'tcx, IsNotCopy> for WithCachedTypeInfo<TyKind<'tcx>>

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut Self

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = Self> ) -> &'a mut [Self]

Auto Trait Implementations§

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impl<T> RefUnwindSafe for WithCachedTypeInfo<T>where T: RefUnwindSafe,

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impl<T> Send for WithCachedTypeInfo<T>where T: Send,

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impl<T> Sync for WithCachedTypeInfo<T>where T: Sync,

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impl<T> Unpin for WithCachedTypeInfo<T>where T: Unpin,

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impl<T> UnwindSafe for WithCachedTypeInfo<T>where T: UnwindSafe,

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere T: Copy,

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fn allocate_on<'a>(self, arena: &'a Arena<'tcx>) -> &'a mut T

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fn allocate_from_iter<'a>( arena: &'a Arena<'tcx>, iter: impl IntoIterator<Item = T> ) -> &'a mut [T]

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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> Rwhere I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<P> IntoQueryParam<P> for P

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<Tcx, T> Value<Tcx> for Twhere Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle: &[QueryInfo], _guar: ErrorGuaranteed ) -> T

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.