rust/library/core/src/str/mod.rs, branch try

Rollup merge of #143423 - hkBst:clippy-fix-1, r=workingjubilee

2025-07-20T13:34:04+00:00

address clippy formatting nits - int_log10.rs: change top level doc comments to outer - collect.rs: remove empty line after doc comment - clippy fix: markdown indentation for indented items after line break: a markdown list item continued over multiples lines, but those following lines which are part of the same item are not indented - clippy fix: bound in one place: when there is a bound in angle brackets and another bound on the same variable in a where clause

Rollup merge of #143921 - oli-obk:const-index, r=fee1-dead

2025-07-16T15:06:41+00:00

Constify `Index` traits tracking issue: rust-lang/rust#143775 the `SliceIndex` trait cannot be implemented by users as it is sealed. While it would be useful for the `get` method on slices, it seems weird to have a feature gate for that that isn't also gating index syntax at the same time, so I put them under the same feature gate. r? ```````@fee1-dead```````

Rollup merge of #143907 - Kijewski:pr-inline-split_at_unchecked, r=Mark-Simulacrum

2025-07-15T10:52:41+00:00

core: make `str::split_at_unchecked()` inline This PR adds `#[inline]` to the method `str::split_at_unchecked()`. This is done for two reasons: 1. The method is tiny, e.g. on AMD-64 (): ```asm movq %rdi, %rax subq %rcx, %rdx movq %rsi, (%rdi) addq %rcx, %rsi movq %rcx, 8(%rdi) movq %rsi, 16(%rdi) movq %rdx, 24(%rdi) retq ``` 2. More importantly, inlining the method enables further automatic optimizations. E.g. if you split at index 3, then in the compiler (rustc, llvm or both) knows that this code cannot fail, and the panicking path is omitted in the generated code: ```rust pub fn punctuation(i: &str) -> Result<(), ()> { const THREE_CHARS: &[[u8; 3]] = &[*b"<<=", *b">>=", *b"...", *b"..="]; if let Some((head, _)) = i.split_at_checked(3) && THREE_CHARS.contains(&head.as_bytes().try_into().unwrap()) { Ok(()) } else { Err(()) } } ```

Without PR

```asm playground::punctuation: subq $40, %rsp movq %rsi, %rdx movq %rdi, %rsi movb $1, %al cmpq $3, %rdx ja .LBB2_2 je .LBB2_3 .LBB2_11: addq $40, %rsp retq .LBB2_2: cmpb $-64, 3(%rsi) jl .LBB2_11 .LBB2_3: leaq 8(%rsp), %rdi movl $3, %ecx callq *core::str::::split_at_unchecked@GOTPCREL(%rip) movq 8(%rsp), %rcx movb $1, %al testq %rcx, %rcx je .LBB2_11 cmpq $3, 16(%rsp) jne .LBB2_12 movzwl (%rcx), %edx movzbl 2(%rcx), %ecx shll $16, %ecx orl %edx, %ecx cmpl $4013115, %ecx jg .LBB2_8 cmpl $3026478, %ecx je .LBB2_10 cmpl $4009518, %ecx je .LBB2_10 jmp .LBB2_11 .LBB2_8: cmpl $4013630, %ecx je .LBB2_10 cmpl $4013116, %ecx jne .LBB2_11 .LBB2_10: xorl %eax, %eax addq $40, %rsp retq .LBB2_12: leaq .Lanon.d98a7fbb86d10a97c24516e267466134.2(%rip), %rdi leaq .Lanon.d98a7fbb86d10a97c24516e267466134.1(%rip), %rcx leaq .Lanon.d98a7fbb86d10a97c24516e267466134.6(%rip), %r8 leaq 7(%rsp), %rdx movl $43, %esi callq *core::result::unwrap_failed@GOTPCREL(%rip) ```

With PR

```asm playground::punctuation: movb $1, %al cmpq $3, %rsi ja .LBB0_2 je .LBB0_3 .LBB0_9: retq .LBB0_2: cmpb $-64, 3(%rdi) jl .LBB0_9 .LBB0_3: movzwl (%rdi), %eax movzbl 2(%rdi), %ecx shll $16, %ecx orl %eax, %ecx movb $1, %al cmpl $4013115, %ecx jg .LBB0_6 cmpl $3026478, %ecx je .LBB0_8 cmpl $4009518, %ecx je .LBB0_8 jmp .LBB0_9 .LBB0_6: cmpl $4013630, %ecx je .LBB0_8 cmpl $4013116, %ecx jne .LBB0_9 .LBB0_8: xorl %eax, %eax retq ```

constify some methods using `SliceIndex`

2025-07-15T07:58:29+00:00

core: make `str::split_at_unchecked()` inline

2025-07-13T21:00:42+00:00

This PR adds `#[inline]` to the method `str::split_at_unchecked()`. This is done for two reasons: 1. The method is tiny, e.g. on AMD-64 (): ```asm movq %rdi, %rax subq %rcx, %rdx movq %rsi, (%rdi) addq %rcx, %rsi movq %rcx, 8(%rdi) movq %rsi, 16(%rdi) movq %rdx, 24(%rdi) retq ``` 2. More importantly, inlining the method enables further automatic optimizations. E.g. if you split at index 3, then in the compiler (rustc, llvm or both) knows that this code cannot fail, and the panicking path is omitted in the generated code: ```rust pub fn punctuation(i: &str) -> Result<(), ()> { const THREE_CHARS: &[[u8; 3]] = &[*b"<<=", *b">>=", *b"...", *b"..="]; if let Some((head, _)) = i.split_at_checked(3) && THREE_CHARS.contains(&head.as_bytes().try_into().unwrap()) { Ok(()) } else { Err(()) } } ```

Without PR

With PR

update issue number for `const_trait_impl`

2025-07-13T15:55:06+00:00

collect.rs: remove empty line after doc comment

2025-07-08T11:48:15+00:00

Make `Default` const and add some `const Default` impls

2025-07-07T22:09:37+00:00

Full list of `impl const Default` types: - () - bool - char - Cell - std::ascii::Char - usize - u8 - u16 - u32 - u64 - u128 - i8 - i16 - i32 - i64 - i128 - f16 - f32 - f64 - f128 - std::marker::PhantomData - Option - std::iter::Empty - std::ptr::Alignment - &[T] - &mut [T] - &str - &mut str - String - Vec

lib: more eagerly return `self.len()` from `ceil_char_boundary`

2025-07-06T23:14:58+00:00

There is no reason to go through the complicated branch as it would always return `self.len()` in this case. Also helps debug code somewhat and I guess might make optimizations easier (although I haven't really a sample to demonstrate this.) ref. #93743 Suggested by @chrisduerr

Update version placeholders

2025-07-01T17:54:33+00:00