Stabilize new inclusive range type and iterator type by pitaj · Pull Request #150522 · rust-lang/rust

pitaj · 2025-12-30T21:07:01Z

Part 1 of stabilizing the new range types for #125687

stabilizes core::range::RangeInclusive and core::range::RangeInclusiveIter. Newly stable API:

// in core and std
pub mod range;

// in core::range

pub struct RangeInclusive<Idx> {
    pub start: Idx,
    pub last: Idx,
}

impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> { /* ... */ }

impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> {
    pub const fn contains<U>(&self, item: &U) -> bool
    where
        Idx: [const] PartialOrd<U>,
        U: ?Sized + [const] PartialOrd<Idx>;

    pub const fn is_empty(&self) -> bool
    where
        Idx: [const] PartialOrd;
}

impl<Idx: Step> RangeInclusive<Idx> {
    pub fn iter(&self) -> RangeInclusiveIter<Idx>;
}

impl<T> const RangeBounds<T> for RangeInclusive<T> { /* ... */ }
impl<T> const RangeBounds<T> for RangeInclusive<&T> { /* ... */ }

impl<T> const From<RangeInclusive<T>> for legacy::RangeInclusive<T> { /* ... */ }
impl<T> const From<legacy::RangeInclusive<T>> for RangeInclusive<T> { /* ... */ }

pub struct RangeInclusiveIter<A>(/* ... */);

impl<A: Step> RangeInclusiveIter<A> {
    pub fn remainder(self) -> Option<RangeInclusive<A>>;
}

impl<A: Step> Iterator for RangeInclusiveIter<A> {
    type Item = A;
    /* ... */
}

impl<A: Step> DoubleEndedIterator for RangeInclusiveIter<A> { /* ... */ }
impl<A: Step> FusedIterator for RangeInclusiveIter<A> { }
impl<A: Step> IntoIterator for RangeInclusive<A> {
    type Item = A;
    type IntoIter = RangeInclusiveIter<A>;
    /* ... */
}

impl ExactSizeIterator for RangeInclusiveIter<u8> { }
impl ExactSizeIterator for RangeInclusiveIter<i8> { }

unsafe impl<T> const SliceIndex<[T]> for range::RangeInclusive<usize> {
    type Output = [T];
    /* ... */
}
unsafe impl const SliceIndex<str> for range::RangeInclusive<usize> {
    type Output = str;
    /* ... */
}

I've removed the re-exports temporarily because from what I can tell, there's no way to make re-exports of stable items unstable. They will be added back and stabilized in a separate PR.

rustbot · 2025-12-30T21:07:06Z

r? @jackh726

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jackh726 · 2025-12-31T01:57:33Z

r? libs-api

library/core/src/range.rs

rustbot · 2026-01-24T01:30:24Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

library/core/src/range.rs

tgross35 · 2026-01-24T01:55:49Z

I added an API summary of what is stabilized here to the top post, nominating for @rust-lang/libs-api to double check and nudge the FCP. There is an ongoing proposed FCP at #125687 (comment), but maybe it makes sense to restart it here with smaller scope?

Everything seems to match up with the traits available on ops::RangeInclusive, delta ExactSizeIterator for i16/u16 (expected as it is incorrect on 16-bit targets).

Two small concerns found from digging around the issue and other discussion:

Stabilize new inclusive range type and iterator type #150522 (comment) is the intent to exclude is_empty for now?
Field names are "start" and "last" which don't typically go together. It used to be "start" and "end" like for Range, but end was renamed at Rename end field of inclusive Range APIs to last libs-team#511 to avoid a footgun. Should we consider start->first so we have "first" and "last"?

@rustbot label +I-libs-api-nominated

scottmcm · 2026-01-24T09:24:42Z

Field names are "start" and "last" which don't typically go together. It used to be "start" and "end" like

TBH, I never thought "start" and "end" went together either. A race is start-to-finish where you place somewhere in first..=last; a story commonly has a beginning, middle, and end.

Are any of those better enough to bother changing something? Dunno.

sendittothenewts · 2026-01-26T11:22:54Z

Should we consider `start`->`first` so we have "first" and "last"?

When I suggested changing end to last on the inclusive ranges, it did occur to me that this would be more consistent. I didn't suggest this change because it would bring Range, RangeFrom and arguably RangeBounds::start_bound into the blast radius for little benefit. Also, there is no first method on iterators to be consistent with.

Amanieu · 2026-01-27T16:51:41Z

We discussed the field names in the @rust-lang/libs-api meeting and were inclined to keep them as they currently are.

pitaj · 2026-01-27T17:25:28Z

As they currently are in this PR, or as they currently are on the old RangeInclusive types?

tgross35 · 2026-01-31T04:17:13Z

As they currently are in this PR, or as they currently are on the old RangeInclusive types?

I believe as they are in this PR. From the meeting notes at https://hackmd.io/_EpeHNVySbqHWCSqXwLX1w#nominated-rusttf150522-Stabilize-new-inclusive-range-type-and-iterator-type

Amanieu: I'm happy with "start" and "last". Any objections?
[...]
Josh: I'd ship the currently proposed API.

And no different names mentioned.

pitaj · 2026-02-07T02:41:14Z

@rustbot ready

I can rebase and squash everything together upon approval

tgross35

FCP completed at #125687 (comment). The basic API is consistent with what is in #125687 (comment) and the few traits not mentioned there match up with existing range types (as I noted at #150522 (comment)). libs-api has also had a chance to talk about this in their meeting so I think everything is all set.

r=me with a squash.

View changes since this review

tgross35 · 2026-02-07T04:18:44Z

@bors delegate+

rust-bors · 2026-02-07T04:18:47Z

✌️ @pitaj, you can now approve this pull request!

If @tgross35 told you to "r=me" after making some further change, then please make that change and post @bors r=tgross35.

stabilizes `core::range::RangeInclusive` and `core::range::RangeInclusiveIter` and the `core::range` module

rustbot · 2026-02-07T04:37:28Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

pitaj · 2026-02-07T04:38:56Z

@bors r=tgross35

rust-bors · 2026-02-07T04:38:59Z

📌 Commit d2020fb has been approved by tgross35

It is now in the queue for this repository.

…, r=tgross35 Stabilize new inclusive range type and iterator type Part 1 of stabilizing the new range types for rust-lang#125687 stabilizes `core::range::RangeInclusive` and `core::range::RangeInclusiveIter`. Newly stable API: ```rust // in core and std pub mod range; // in core::range pub struct RangeInclusive<Idx> { pub start: Idx, pub last: Idx, } impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> { /* ... */ } impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> { pub const fn contains(&self, item: &U) -> bool where Idx: [const] PartialOrd, U: ?Sized + [const] PartialOrd<Idx>; pub const fn is_empty(&self) -> bool where Idx: [const] PartialOrd; } impl<Idx: Step> RangeInclusive<Idx> { pub fn iter(&self) -> RangeInclusiveIter<Idx>; } impl<T> const RangeBounds<T> for RangeInclusive<T> { /* ... */ } impl<T> const RangeBounds<T> for RangeInclusive<&T> { /* ... */ } impl<T> const From<RangeInclusive<T>> for legacy::RangeInclusive<T> { /* ... */ } impl<T> const From<legacy::RangeInclusive<T>> for RangeInclusive<T> { /* ... */ } pub struct RangeInclusiveIter<A>(/* ... */); impl<A: Step> RangeInclusiveIter<A> { pub fn remainder(self) -> Option<RangeInclusive<A>>; } impl<A: Step> Iterator for RangeInclusiveIter<A> { type Item = A; /* ... */ } impl<A: Step> DoubleEndedIterator for RangeInclusiveIter<A> { /* ... */ } impl<A: Step> FusedIterator for RangeInclusiveIter<A> { } impl<A: Step> IntoIterator for RangeInclusive<A> { type Item = A; type IntoIter = RangeInclusiveIter<A>; /* ... */ } impl ExactSizeIterator for RangeInclusiveIter<u8> { } impl ExactSizeIterator for RangeInclusiveIter<i8> { } unsafe impl<T> const SliceIndex<[T]> for range::RangeInclusive<usize> { type Output = [T]; /* ... */ } unsafe impl const SliceIndex<str> for range::RangeInclusive<usize> { type Output = str; /* ... */ } ``` I've removed the re-exports temporarily because from what I can tell, there's no way to make re-exports of stable items unstable. They will be added back and stabilized in a separate PR.

Rollup of 4 pull requests Successful merges: - #148590 (Stabilize `atomic_try_update`and deprecate `fetch_update` starting 1.99.0) - #150522 (Stabilize new inclusive range type and iterator type) - #151576 (Stabilize `core::hint::cold_path`) - #152199 (Move `rustc_query_system::cache`.)

…, r=tgross35 Stabilize new inclusive range type and iterator type Part 1 of stabilizing the new range types for rust-lang#125687 stabilizes `core::range::RangeInclusive` and `core::range::RangeInclusiveIter`. Newly stable API: ```rust // in core and std pub mod range; // in core::range pub struct RangeInclusive<Idx> { pub start: Idx, pub last: Idx, } impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> { /* ... */ } impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> { pub const fn contains(&self, item: &U) -> bool where Idx: [const] PartialOrd, U: ?Sized + [const] PartialOrd<Idx>; pub const fn is_empty(&self) -> bool where Idx: [const] PartialOrd; } impl<Idx: Step> RangeInclusive<Idx> { pub fn iter(&self) -> RangeInclusiveIter<Idx>; } impl<T> const RangeBounds<T> for RangeInclusive<T> { /* ... */ } impl<T> const RangeBounds<T> for RangeInclusive<&T> { /* ... */ } impl<T> const From<RangeInclusive<T>> for legacy::RangeInclusive<T> { /* ... */ } impl<T> const From<legacy::RangeInclusive<T>> for RangeInclusive<T> { /* ... */ } pub struct RangeInclusiveIter<A>(/* ... */); impl<A: Step> RangeInclusiveIter<A> { pub fn remainder(self) -> Option<RangeInclusive<A>>; } impl<A: Step> Iterator for RangeInclusiveIter<A> { type Item = A; /* ... */ } impl<A: Step> DoubleEndedIterator for RangeInclusiveIter<A> { /* ... */ } impl<A: Step> FusedIterator for RangeInclusiveIter<A> { } impl<A: Step> IntoIterator for RangeInclusive<A> { type Item = A; type IntoIter = RangeInclusiveIter<A>; /* ... */ } impl ExactSizeIterator for RangeInclusiveIter<u8> { } impl ExactSizeIterator for RangeInclusiveIter<i8> { } unsafe impl<T> const SliceIndex<[T]> for range::RangeInclusive<usize> { type Output = [T]; /* ... */ } unsafe impl const SliceIndex<str> for range::RangeInclusive<usize> { type Output = str; /* ... */ } ``` I've removed the re-exports temporarily because from what I can tell, there's no way to make re-exports of stable items unstable. They will be added back and stabilized in a separate PR.

…uwer Rollup of 8 pull requests Successful merges: - #148590 (Stabilize `atomic_try_update`and deprecate `fetch_update` starting 1.99.0) - #150522 (Stabilize new inclusive range type and iterator type) - #152235 (Convert to inline diagnostics in `rustc_parse`) - #152267 (feat: Implement `int_from_ascii` for `NonZero<T>`) - #151576 (Stabilize `core::hint::cold_path`) - #151933 (Linker-plugin-based LTO: give an explanation how to use linker-plugin-lto with full LTO) - #152010 (Ignore all debuginfo tests for LLDB that we do not run in CI) - #152199 (Move `rustc_query_system::cache`.)

Rollup merge of #150522 - pitaj:stabilize-new-rangeinclusive, r=tgross35 Stabilize new inclusive range type and iterator type Part 1 of stabilizing the new range types for #125687 stabilizes `core::range::RangeInclusive` and `core::range::RangeInclusiveIter`. Newly stable API: ```rust // in core and std pub mod range; // in core::range pub struct RangeInclusive<Idx> { pub start: Idx, pub last: Idx, } impl<Idx: fmt::Debug> fmt::Debug for RangeInclusive<Idx> { /* ... */ } impl<Idx: PartialOrd<Idx>> RangeInclusive<Idx> { pub const fn contains(&self, item: &U) -> bool where Idx: [const] PartialOrd, U: ?Sized + [const] PartialOrd<Idx>; pub const fn is_empty(&self) -> bool where Idx: [const] PartialOrd; } impl<Idx: Step> RangeInclusive<Idx> { pub fn iter(&self) -> RangeInclusiveIter<Idx>; } impl<T> const RangeBounds<T> for RangeInclusive<T> { /* ... */ } impl<T> const RangeBounds<T> for RangeInclusive<&T> { /* ... */ } impl<T> const From<RangeInclusive<T>> for legacy::RangeInclusive<T> { /* ... */ } impl<T> const From<legacy::RangeInclusive<T>> for RangeInclusive<T> { /* ... */ } pub struct RangeInclusiveIter<A>(/* ... */); impl<A: Step> RangeInclusiveIter<A> { pub fn remainder(self) -> Option<RangeInclusive<A>>; } impl<A: Step> Iterator for RangeInclusiveIter<A> { type Item = A; /* ... */ } impl<A: Step> DoubleEndedIterator for RangeInclusiveIter<A> { /* ... */ } impl<A: Step> FusedIterator for RangeInclusiveIter<A> { } impl<A: Step> IntoIterator for RangeInclusive<A> { type Item = A; type IntoIter = RangeInclusiveIter<A>; /* ... */ } impl ExactSizeIterator for RangeInclusiveIter<u8> { } impl ExactSizeIterator for RangeInclusiveIter<i8> { } unsafe impl<T> const SliceIndex<[T]> for range::RangeInclusive<usize> { type Output = [T]; /* ... */ } unsafe impl const SliceIndex<str> for range::RangeInclusive<usize> { type Output = str; /* ... */ } ``` I've removed the re-exports temporarily because from what I can tell, there's no way to make re-exports of stable items unstable. They will be added back and stabilized in a separate PR.

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stabilize new inclusive range type and iter

d2020fb

stabilizes `core::range::RangeInclusive` and `core::range::RangeInclusiveIter` and the `core::range` module

pitaj force-pushed the stabilize-new-rangeinclusive branch from f458fc7 to d2020fb Compare February 7, 2026 04:37

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 7, 2026

jhpratt mentioned this pull request Feb 7, 2026

Rollup of 4 pull requests #152266

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Rollup of 9 pull requests #152279

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Rollup of 8 pull requests #152282

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tgross35 mentioned this pull request Feb 9, 2026

Tracking Issue for new_range_api (part of RFC 3550) #125687

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tgross35 added the relnotes Marks issues that should be documented in the release notes of the next release. label Mar 2, 2026

rustbot mentioned this pull request Mar 2, 2026

Tracking issue for release notes of #150522: Stabilize new inclusive range type and iterator type #153306

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tgross35 mentioned this pull request Mar 4, 2026

stabilize new RangeFrom type and iterator #153380

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