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str: Stabilize round_char_boundary feature #145756

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Merged
merged 1 commit into from
Aug 30, 2025
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str: Stabilize round_char_boundary feature #145756

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2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@
#![allow(rustc::diagnostic_outside_of_impl)]
#![allow(rustc::direct_use_of_rustc_type_ir)]
#![allow(rustc::untranslatable_diagnostic)]
#![cfg_attr(bootstrap, feature(round_char_boundary))]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(allocator_api)]
Expand All @@ -51,7 +52,6 @@
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(ptr_alignment_type)]
#![feature(round_char_boundary)]
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Won't you need to cfg_attr(bootstrap, …) the feature in the compiler itself (two instances)?

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You'll need to do this in Clippy's clippy_lints crate as well, since it can now be built by the stage0 compiler.

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@okaneco okaneco Aug 22, 2025 •
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Thanks, I haven't stabilized a feature that touched these other parts of the compiler before.

I manually reordered the cfg_attr features because tidy check complained about alphabetic ordering, but it didn't suggest what line to place it. I couldn't find an automatic --fix option either. Running ./x fmt didn't seem to adjust it either but maybe I have the setup configured wrong (I have it set to the library contributing mode, not sure if that changes anything).

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@samueltardieu samueltardieu Aug 22, 2025 •
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x fmt doesn't reorder AFAICT, you have to put the inner attributes in order by hand (as you did).

Clippy using stage 0 is new and doesn't care about inner attributes order, what you did (order by feature name) is fine as well there.

#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
#![feature(sized_hierarchy)]
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2 changes: 1 addition & 1 deletion compiler/rustc_span/src/lib.rs
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Expand Up @@ -17,6 +17,7 @@

// tidy-alphabetical-start
#![allow(internal_features)]
#![cfg_attr(bootstrap, feature(round_char_boundary))]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(array_windows)]
Expand All @@ -26,7 +27,6 @@
#![feature(map_try_insert)]
#![feature(negative_impls)]
#![feature(read_buf)]
#![feature(round_char_boundary)]
#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
// tidy-alphabetical-end
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1 change: 0 additions & 1 deletion library/alloctests/tests/lib.rs
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Expand Up @@ -23,7 +23,6 @@
#![feature(inplace_iteration)]
#![feature(iter_advance_by)]
#![feature(iter_next_chunk)]
#![feature(round_char_boundary)]
#![feature(slice_partition_dedup)]
#![feature(string_from_utf8_lossy_owned)]
#![feature(string_remove_matches)]
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8 changes: 4 additions & 4 deletions library/core/src/str/mod.rs
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Expand Up @@ -396,7 +396,6 @@ impl str {
/// # Examples
///
/// ```
/// #![feature(round_char_boundary)]
/// let s = "❤️🧡💛💚💙💜";
/// assert_eq!(s.len(), 26);
/// assert!(!s.is_char_boundary(13));
Expand All @@ -405,7 +404,8 @@ impl str {
/// assert_eq!(closest, 10);
/// assert_eq!(&s[..closest], "❤️🧡");
/// ```
#[unstable(feature = "round_char_boundary", issue = "93743")]
#[stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
#[rustc_const_stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
#[inline]
pub const fn floor_char_boundary(&self, index: usize) -> usize {
if index >= self.len() {
Expand Down Expand Up @@ -439,7 +439,6 @@ impl str {
/// # Examples
///
/// ```
/// #![feature(round_char_boundary)]
/// let s = "❤️🧡💛💚💙💜";
/// assert_eq!(s.len(), 26);
/// assert!(!s.is_char_boundary(13));
Expand All @@ -448,7 +447,8 @@ impl str {
/// assert_eq!(closest, 14);
/// assert_eq!(&s[..closest], "❤️🧡💛");
/// ```
#[unstable(feature = "round_char_boundary", issue = "93743")]
#[stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
#[rustc_const_stable(feature = "round_char_boundary", since = "CURRENT_RUSTC_VERSION")]
#[inline]
pub const fn ceil_char_boundary(&self, index: usize) -> usize {
if index >= self.len() {
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1 change: 0 additions & 1 deletion library/std/src/lib.rs
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Expand Up @@ -263,7 +263,6 @@
all(target_vendor = "fortanix", target_env = "sgx"),
feature(slice_index_methods, coerce_unsized, sgx_platform)
)]
#![cfg_attr(any(windows, target_os = "uefi"), feature(round_char_boundary))]
#![cfg_attr(target_family = "wasm", feature(stdarch_wasm_atomic_wait))]
#![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
//
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2 changes: 1 addition & 1 deletion src/librustdoc/lib.rs
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@@ -1,4 +1,5 @@
// tidy-alphabetical-start
#![cfg_attr(bootstrap, feature(round_char_boundary))]
#![doc(
html_root_url = "https://doc.rust-lang.org/nightly/",
html_playground_url = "https://play.rust-lang.org/"
Expand All @@ -12,7 +13,6 @@
#![feature(format_args_nl)]
#![feature(if_let_guard)]
#![feature(iter_intersperse)]
#![feature(round_char_boundary)]
#![feature(rustc_private)]
#![feature(test)]
#![warn(rustc::internal)]
Expand Down
2 changes: 1 addition & 1 deletion src/tools/clippy/clippy_lints/src/lib.rs
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Expand Up @@ -7,7 +7,7 @@
#![feature(iter_intersperse)]
#![feature(iter_partition_in_place)]
#![feature(never_type)]
#![feature(round_char_boundary)]
#![cfg_attr(bootstrap, feature(round_char_boundary))]
#![feature(rustc_private)]
#![feature(stmt_expr_attributes)]
#![feature(unwrap_infallible)]
Expand Down
1 change: 0 additions & 1 deletion src/tools/clippy/tests/ui/char_indices_as_byte_indices.fixed
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@@ -1,4 +1,3 @@
#![feature(round_char_boundary)]
#![warn(clippy::char_indices_as_byte_indices)]

trait StrExt {
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1 change: 0 additions & 1 deletion src/tools/clippy/tests/ui/char_indices_as_byte_indices.rs
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@@ -1,4 +1,3 @@
#![feature(round_char_boundary)]
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You need to run ./x.py test clippy --bless to update the stderr file with the line number changes.

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Addressed in c5c6520

#![warn(clippy::char_indices_as_byte_indices)]

trait StrExt {
Expand Down
28 changes: 14 additions & 14 deletions src/tools/clippy/tests/ui/char_indices_as_byte_indices.stderr
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Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
error: indexing into a string with a character position where a byte index is expected
--> tests/ui/char_indices_as_byte_indices.rs:13:24
--> tests/ui/char_indices_as_byte_indices.rs:12:24
|
LL | let _ = prim[..idx];
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:12:10
--> tests/ui/char_indices_as_byte_indices.rs:11:10
|
LL | for (idx, _) in prim.chars().enumerate() {
| ^^^ ^^^^^^^^^^^
Expand All @@ -19,14 +19,14 @@ LL + for (idx, _) in prim.char_indices() {
|

error: passing a character position to a method that expects a byte index
--> tests/ui/char_indices_as_byte_indices.rs:15:23
--> tests/ui/char_indices_as_byte_indices.rs:14:23
|
LL | prim.split_at(idx);
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:12:10
--> tests/ui/char_indices_as_byte_indices.rs:11:10
|
LL | for (idx, _) in prim.chars().enumerate() {
| ^^^ ^^^^^^^^^^^
Expand All @@ -37,14 +37,14 @@ LL + for (idx, _) in prim.char_indices() {
|

error: passing a character position to a method that expects a byte index
--> tests/ui/char_indices_as_byte_indices.rs:19:49
--> tests/ui/char_indices_as_byte_indices.rs:18:49
|
LL | let _ = prim[..prim.floor_char_boundary(idx)];
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:12:10
--> tests/ui/char_indices_as_byte_indices.rs:11:10
|
LL | for (idx, _) in prim.chars().enumerate() {
| ^^^ ^^^^^^^^^^^
Expand All @@ -55,14 +55,14 @@ LL + for (idx, _) in prim.char_indices() {
|

error: indexing into a string with a character position where a byte index is expected
--> tests/ui/char_indices_as_byte_indices.rs:29:24
--> tests/ui/char_indices_as_byte_indices.rs:28:24
|
LL | let _ = prim[..c.0];
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:28:9
--> tests/ui/char_indices_as_byte_indices.rs:27:9
|
LL | for c in prim.chars().enumerate() {
| ^ ^^^^^^^^^^^
Expand All @@ -73,14 +73,14 @@ LL + for c in prim.char_indices() {
|

error: passing a character position to a method that expects a byte index
--> tests/ui/char_indices_as_byte_indices.rs:31:23
--> tests/ui/char_indices_as_byte_indices.rs:30:23
|
LL | prim.split_at(c.0);
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:28:9
--> tests/ui/char_indices_as_byte_indices.rs:27:9
|
LL | for c in prim.chars().enumerate() {
| ^ ^^^^^^^^^^^
Expand All @@ -91,14 +91,14 @@ LL + for c in prim.char_indices() {
|

error: indexing into a string with a character position where a byte index is expected
--> tests/ui/char_indices_as_byte_indices.rs:36:26
--> tests/ui/char_indices_as_byte_indices.rs:35:26
|
LL | let _ = string[..idx];
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:35:10
--> tests/ui/char_indices_as_byte_indices.rs:34:10
|
LL | for (idx, _) in string.chars().enumerate() {
| ^^^ ^^^^^^^^^^^
Expand All @@ -109,14 +109,14 @@ LL + for (idx, _) in string.char_indices() {
|

error: passing a character position to a method that expects a byte index
--> tests/ui/char_indices_as_byte_indices.rs:38:25
--> tests/ui/char_indices_as_byte_indices.rs:37:25
|
LL | string.split_at(idx);
| ^^^
|
= note: a character can take up more than one byte, so they are not interchangeable
note: position comes from the enumerate iterator
--> tests/ui/char_indices_as_byte_indices.rs:35:10
--> tests/ui/char_indices_as_byte_indices.rs:34:10
|
LL | for (idx, _) in string.chars().enumerate() {
| ^^^ ^^^^^^^^^^^
Expand Down
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