Struct rustc_middle::mir::interpret::allocation::InitChunkIter
source · Expand description
Yields InitChunk
s. See InitMask::range_as_init_chunks
.
Fields
init_mask: &'a InitMask
is_init: bool
Whether the next chunk we will return is initialized. If there are no more chunks, contains some arbitrary value.
start: Size
The current byte index into init_mask
.
end: Size
The end byte index into init_mask
.
Trait Implementations
sourceimpl<'a> Clone for InitChunkIter<'a>
impl<'a> Clone for InitChunkIter<'a>
sourcefn clone(&self) -> InitChunkIter<'a>ⓘNotable traits for InitChunkIter<'a>impl<'a> Iterator for InitChunkIter<'a> type Item = InitChunk;
fn clone(&self) -> InitChunkIter<'a>ⓘNotable traits for InitChunkIter<'a>impl<'a> Iterator for InitChunkIter<'a> type Item = InitChunk;
Returns a copy of the value. Read more
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source
. Read moresourceimpl<'a> Iterator for InitChunkIter<'a>
impl<'a> Iterator for InitChunkIter<'a>
sourcefn next(&mut self) -> Option<Self::Item>
fn next(&mut self) -> Option<Self::Item>
Advances the iterator and returns the next value. Read more
sourcefn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>
fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>
🔬This is a nightly-only experimental API. (
iter_next_chunk
)Advances the iterator and returns an array containing the next
N
values. Read more1.0.0 · sourcefn size_hint(&self) -> (usize, Option<usize>)
fn size_hint(&self) -> (usize, Option<usize>)
Returns the bounds on the remaining length of the iterator. Read more
1.0.0 · sourcefn count(self) -> usize
fn count(self) -> usize
Consumes the iterator, counting the number of iterations and returning it. Read more
1.0.0 · sourcefn last(self) -> Option<Self::Item>
fn last(self) -> Option<Self::Item>
Consumes the iterator, returning the last element. Read more
sourcefn advance_by(&mut self, n: usize) -> Result<(), usize>
fn advance_by(&mut self, n: usize) -> Result<(), usize>
🔬This is a nightly-only experimental API. (
iter_advance_by
)Advances the iterator by
n
elements. Read more1.0.0 · sourcefn nth(&mut self, n: usize) -> Option<Self::Item>
fn nth(&mut self, n: usize) -> Option<Self::Item>
Returns the
n
th element of the iterator. Read more1.28.0 · sourcefn step_by(self, step: usize) -> StepBy<Self>
fn step_by(self, step: usize) -> StepBy<Self>
Creates an iterator starting at the same point, but stepping by
the given amount at each iteration. Read more
1.0.0 · sourcefn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator<Item = Self::Item>,
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator<Item = Self::Item>,
Takes two iterators and creates a new iterator over both in sequence. Read more
1.0.0 · sourcefn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator,
fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
U: IntoIterator,
‘Zips up’ two iterators into a single iterator of pairs. Read more
sourcefn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
G: FnMut() -> Self::Item,
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>where
G: FnMut() -> Self::Item,
🔬This is a nightly-only experimental API. (
iter_intersperse
)Creates a new iterator which places an item generated by
separator
between adjacent items of the original iterator. Read more1.0.0 · sourcefn map<B, F>(self, f: F) -> Map<Self, F>where
F: FnMut(Self::Item) -> B,
fn map<B, F>(self, f: F) -> Map<Self, F>where
F: FnMut(Self::Item) -> B,
Takes a closure and creates an iterator which calls that closure on each
element. Read more
1.21.0 · sourcefn for_each<F>(self, f: F)where
F: FnMut(Self::Item),
fn for_each<F>(self, f: F)where
F: FnMut(Self::Item),
Calls a closure on each element of an iterator. Read more
1.0.0 · sourcefn filter<P>(self, predicate: P) -> Filter<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn filter<P>(self, predicate: P) -> Filter<Self, P>where
P: FnMut(&Self::Item) -> bool,
Creates an iterator which uses a closure to determine if an element
should be yielded. Read more
1.0.0 · sourcefn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
F: FnMut(Self::Item) -> Option<B>,
fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>where
F: FnMut(Self::Item) -> Option<B>,
Creates an iterator that both filters and maps. Read more
1.0.0 · sourcefn enumerate(self) -> Enumerate<Self>
fn enumerate(self) -> Enumerate<Self>
Creates an iterator which gives the current iteration count as well as
the next value. Read more
1.0.0 · sourcefn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
1.0.0 · sourcefn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>where
P: FnMut(&Self::Item) -> bool,
Creates an iterator that yields elements based on a predicate. Read more
1.57.0 · sourcefn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
P: FnMut(Self::Item) -> Option<B>,
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>where
P: FnMut(Self::Item) -> Option<B>,
Creates an iterator that both yields elements based on a predicate and maps. Read more
1.0.0 · sourcefn skip(self, n: usize) -> Skip<Self>
fn skip(self, n: usize) -> Skip<Self>
Creates an iterator that skips the first
n
elements. Read more1.0.0 · sourcefn take(self, n: usize) -> Take<Self>
fn take(self, n: usize) -> Take<Self>
Creates an iterator that yields the first
n
elements, or fewer
if the underlying iterator ends sooner. Read more1.0.0 · sourcefn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
F: FnMut(&mut St, Self::Item) -> Option<B>,
fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F>where
F: FnMut(&mut St, Self::Item) -> Option<B>,
1.0.0 · sourcefn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
U: IntoIterator,
F: FnMut(Self::Item) -> U,
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>where
U: IntoIterator,
F: FnMut(Self::Item) -> U,
Creates an iterator that works like map, but flattens nested structure. Read more
1.0.0 · sourcefn inspect<F>(self, f: F) -> Inspect<Self, F>where
F: FnMut(&Self::Item),
fn inspect<F>(self, f: F) -> Inspect<Self, F>where
F: FnMut(&Self::Item),
Does something with each element of an iterator, passing the value on. Read more
1.0.0 · sourcefn by_ref(&mut self) -> &mut Self
fn by_ref(&mut self) -> &mut Self
Borrows an iterator, rather than consuming it. Read more
1.0.0 · sourcefn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
fn collect<B>(self) -> Bwhere
B: FromIterator<Self::Item>,
Transforms an iterator into a collection. Read more
sourcefn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
fn collect_into<E>(self, collection: &mut E) -> &mut Ewhere
E: Extend<Self::Item>,
🔬This is a nightly-only experimental API. (
iter_collect_into
)Collects all the items from an iterator into a collection. Read more
1.0.0 · sourcefn partition<B, F>(self, f: F) -> (B, B)where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
fn partition<B, F>(self, f: F) -> (B, B)where
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
Consumes an iterator, creating two collections from it. Read more
sourcefn is_partitioned<P>(self, predicate: P) -> boolwhere
P: FnMut(Self::Item) -> bool,
fn is_partitioned<P>(self, predicate: P) -> boolwhere
P: FnMut(Self::Item) -> bool,
🔬This is a nightly-only experimental API. (
iter_is_partitioned
)Checks if the elements of this iterator are partitioned according to the given predicate,
such that all those that return
true
precede all those that return false
. Read more1.27.0 · sourcefn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> Rwhere
F: FnMut(B, Self::Item) -> R,
R: Try<Output = B>,
An iterator method that applies a function as long as it returns
successfully, producing a single, final value. Read more
1.27.0 · sourcefn try_for_each<F, R>(&mut self, f: F) -> Rwhere
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
fn try_for_each<F, R>(&mut self, f: F) -> Rwhere
F: FnMut(Self::Item) -> R,
R: Try<Output = ()>,
An iterator method that applies a fallible function to each item in the
iterator, stopping at the first error and returning that error. Read more
1.0.0 · sourcefn fold<B, F>(self, init: B, f: F) -> Bwhere
F: FnMut(B, Self::Item) -> B,
fn fold<B, F>(self, init: B, f: F) -> Bwhere
F: FnMut(B, Self::Item) -> B,
Folds every element into an accumulator by applying an operation,
returning the final result. Read more
1.51.0 · sourcefn reduce<F>(self, f: F) -> Option<Self::Item>where
F: FnMut(Self::Item, Self::Item) -> Self::Item,
fn reduce<F>(self, f: F) -> Option<Self::Item>where
F: FnMut(Self::Item, Self::Item) -> Self::Item,
Reduces the elements to a single one, by repeatedly applying a reducing
operation. Read more
sourcefn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryTypewhere
F: FnMut(Self::Item, Self::Item) -> R,
R: Try<Output = Self::Item>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
🔬This is a nightly-only experimental API. (
iterator_try_reduce
)Reduces the elements to a single one by repeatedly applying a reducing operation. If the
closure returns a failure, the failure is propagated back to the caller immediately. Read more
1.0.0 · sourcefn all<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
fn all<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
Tests if every element of the iterator matches a predicate. Read more
1.0.0 · sourcefn any<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
fn any<F>(&mut self, f: F) -> boolwhere
F: FnMut(Self::Item) -> bool,
Tests if any element of the iterator matches a predicate. Read more
1.0.0 · sourcefn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
P: FnMut(&Self::Item) -> bool,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>where
P: FnMut(&Self::Item) -> bool,
Searches for an element of an iterator that satisfies a predicate. Read more
1.30.0 · sourcefn find_map<B, F>(&mut self, f: F) -> Option<B>where
F: FnMut(Self::Item) -> Option<B>,
fn find_map<B, F>(&mut self, f: F) -> Option<B>where
F: FnMut(Self::Item) -> Option<B>,
Applies function to the elements of iterator and returns
the first non-none result. Read more
sourcefn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryTypewhere
F: FnMut(&Self::Item) -> R,
R: Try<Output = bool>,
<R as Try>::Residual: Residual<Option<Self::Item>>,
🔬This is a nightly-only experimental API. (
try_find
)Applies function to the elements of iterator and returns
the first true result or the first error. Read more
1.0.0 · sourcefn position<P>(&mut self, predicate: P) -> Option<usize>where
P: FnMut(Self::Item) -> bool,
fn position<P>(&mut self, predicate: P) -> Option<usize>where
P: FnMut(Self::Item) -> bool,
Searches for an element in an iterator, returning its index. Read more
1.6.0 · sourcefn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the maximum value from the
specified function. Read more
1.15.0 · sourcefn max_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn max_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
Returns the element that gives the maximum value with respect to the
specified comparison function. Read more
1.6.0 · sourcefn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
fn min_by_key<B, F>(self, f: F) -> Option<Self::Item>where
B: Ord,
F: FnMut(&Self::Item) -> B,
Returns the element that gives the minimum value from the
specified function. Read more
1.15.0 · sourcefn min_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
fn min_by<F>(self, compare: F) -> Option<Self::Item>where
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
Returns the element that gives the minimum value with respect to the
specified comparison function. Read more
1.0.0 · sourcefn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)where
FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Iterator<Item = (A, B)>,
Converts an iterator of pairs into a pair of containers. Read more
1.36.0 · sourcefn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Iterator<Item = &'a T>,
fn copied<'a, T>(self) -> Copied<Self>where
T: 'a + Copy,
Self: Iterator<Item = &'a T>,
Creates an iterator which copies all of its elements. Read more
1.0.0 · sourcefn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Iterator<Item = &'a T>,
fn cloned<'a, T>(self) -> Cloned<Self>where
T: 'a + Clone,
Self: Iterator<Item = &'a T>,
1.0.0 · sourcefn cycle(self) -> Cycle<Self>where
Self: Clone,
fn cycle(self) -> Cycle<Self>where
Self: Clone,
Repeats an iterator endlessly. Read more
sourcefn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>
fn array_chunks<const N: usize>(self) -> ArrayChunks<Self, N>
🔬This is a nightly-only experimental API. (
iter_array_chunks
)Returns an iterator over
N
elements of the iterator at a time. Read more1.11.0 · sourcefn sum<S>(self) -> Swhere
S: Sum<Self::Item>,
fn sum<S>(self) -> Swhere
S: Sum<Self::Item>,
Sums the elements of an iterator. Read more
1.11.0 · sourcefn product<P>(self) -> Pwhere
P: Product<Self::Item>,
fn product<P>(self) -> Pwhere
P: Product<Self::Item>,
Iterates over the entire iterator, multiplying all the elements Read more
sourcefn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
fn cmp_by<I, F>(self, other: I, cmp: F) -> Orderingwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Ordering,
🔬This is a nightly-only experimental API. (
iter_order_by
)Lexicographically compares the elements of this
Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn partial_cmp<I>(self, other: I) -> Option<Ordering>where
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
sourcefn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering>where
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> Option<Ordering>,
🔬This is a nightly-only experimental API. (
iter_order_by
)Lexicographically compares the elements of this
Iterator
with those
of another with respect to the specified comparison function. Read more1.5.0 · sourcefn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn eq<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
sourcefn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
fn eq_by<I, F>(self, other: I, eq: F) -> boolwhere
I: IntoIterator,
F: FnMut(Self::Item, <I as IntoIterator>::Item) -> bool,
🔬This is a nightly-only experimental API. (
iter_order_by
)1.5.0 · sourcefn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
fn ne<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
1.5.0 · sourcefn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn lt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this
Iterator
are lexicographically
less than those of another. Read more1.5.0 · sourcefn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn le<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this
Iterator
are lexicographically
less or equal to those of another. Read more1.5.0 · sourcefn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn gt<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this
Iterator
are lexicographically
greater than those of another. Read more1.5.0 · sourcefn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
fn ge<I>(self, other: I) -> boolwhere
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this
Iterator
are lexicographically
greater than or equal to those of another. Read moresourcefn is_sorted_by<F>(self, compare: F) -> boolwhere
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
fn is_sorted_by<F>(self, compare: F) -> boolwhere
F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>,
🔬This is a nightly-only experimental API. (
is_sorted
)Checks if the elements of this iterator are sorted using the given comparator function. Read more
sourcefn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
fn is_sorted_by_key<F, K>(self, f: F) -> boolwhere
F: FnMut(Self::Item) -> K,
K: PartialOrd<K>,
🔬This is a nightly-only experimental API. (
is_sorted
)Checks if the elements of this iterator are sorted using the given key extraction
function. Read more
Auto Trait Implementations
impl<'a> RefUnwindSafe for InitChunkIter<'a>
impl<'a> Send for InitChunkIter<'a>
impl<'a> Sync for InitChunkIter<'a>
impl<'a> Unpin for InitChunkIter<'a>
impl<'a> UnwindSafe for InitChunkIter<'a>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<I, T, R, E> InternAs<[T], R> for Iwhere
E: InternIteratorElement<T, R>,
I: Iterator<Item = E>,
impl<I, T, R, E> InternAs<[T], R> for Iwhere
E: InternIteratorElement<T, R>,
I: Iterator<Item = E>,
type Output = <E as InternIteratorElement<T, R>>::Output
fn intern_with<F>(self, f: F) -> <I as InternAs<[T], R>>::Outputwhere
F: FnOnce(&[T]) -> R,
sourceimpl<T, R> InternIteratorElement<T, R> for T
impl<T, R> InternIteratorElement<T, R> for T
type Output = R
fn intern_with<I, F>(iter: I, f: F) -> <T as InternIteratorElement<T, R>>::Outputwhere
I: Iterator<Item = T>,
F: FnOnce(&[T]) -> R,
sourceimpl<I> IntoIterator for Iwhere
I: Iterator,
impl<I> IntoIterator for Iwhere
I: Iterator,
sourceimpl<T> MaybeResult<T> for T
impl<T> MaybeResult<T> for T
sourceimpl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
impl<CTX, T> Value<CTX> for Twhere
CTX: DepContext,
default fn from_cycle_error(tcx: CTX) -> T
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
Layout
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.
Size: 32 bytes