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Mark the StepBy specialization as unsafe

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The 8472 2023-06-25 18:09:47 +02:00
parent 8a72f35234
commit f174547124
1 changed files with 8 additions and 8 deletions
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16
library/core/src/iter/adapters/step_by.rs
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@ -141,7 +141,7 @@ impl<T> SpecRangeSetup<T> for T {
/// Specialization trait to optimize `StepBy<Range<{integer}>>` iteration.
///
/// # Correctness
/// # Safety
///
/// Technically this is safe to implement (look ma, no unsafe!), but in reality
/// a lot of unsafe code relies on ranges over integers being correct.
@ -149,7 +149,7 @@ impl<T> SpecRangeSetup<T> for T {
/// For correctness *all* public StepBy methods must be specialized
/// because `setup` drastically alters the meaning of the struct fields so that mixing
/// different implementations would lead to incorrect results.
trait StepByImpl<I> {
unsafe trait StepByImpl<I> {
type Item;
fn spec_next(&mut self) -> Option<Self::Item>;
@ -172,13 +172,13 @@ fn spec_fold<Acc, F>(self, acc: Acc, f: F) -> Acc
///
/// See also: `StepByImpl`
///
/// # Correctness
/// # Safety
///
/// The specializations must be implemented together with `StepByImpl`
/// where applicable. I.e. if `StepBy` does support backwards iteration
/// for a given iterator and that is specialized for forward iteration then
/// it must also be specialized for backwards iteration.
trait StepByBackImpl<I> {
unsafe trait StepByBackImpl<I> {
type Item;
fn spec_next_back(&mut self) -> Option<Self::Item>
@ -201,7 +201,7 @@ fn spec_rfold<Acc, F>(self, init: Acc, f: F) -> Acc
F: FnMut(Acc, Self::Item) -> Acc;
}
impl<I: Iterator> StepByImpl<I> for StepBy<I> {
unsafe impl<I: Iterator> StepByImpl<I> for StepBy<I> {
type Item = I::Item;
#[inline]
@ -319,7 +319,7 @@ fn nth<I: Iterator>(iter: &mut I, step: usize) -> impl FnMut() -> Option<I::Item
}
}
impl<I: DoubleEndedIterator + ExactSizeIterator> StepByBackImpl<I> for StepBy<I> {
unsafe impl<I: DoubleEndedIterator + ExactSizeIterator> StepByBackImpl<I> for StepBy<I> {
type Item = I::Item;
#[inline]
@ -416,7 +416,7 @@ fn setup(mut r: Range<$t>, step: usize) -> Range<$t> {
}
}
impl StepByImpl<Range<$t>> for StepBy<Range<$t>> {
unsafe impl StepByImpl<Range<$t>> for StepBy<Range<$t>> {
#[inline]
fn spec_next(&mut self) -> Option<$t> {
// if a step size larger than the type has been specified fall back to
@ -497,7 +497,7 @@ macro_rules! spec_int_ranges_r {
($($t:ty)*) => ($(
const _: () = assert!(usize::BITS >= <$t>::BITS);
impl StepByBackImpl<Range<$t>> for StepBy<Range<$t>> {
unsafe impl StepByBackImpl<Range<$t>> for StepBy<Range<$t>> {
#[inline]
fn spec_next_back(&mut self) -> Option<Self::Item>