new lint: `redundant_locals`
This lint checks for code like the following:
```rs
let x = 1;
let x = x;
```
It checks (afaik) all cases where a binding is shadowed by its own value in the same block, including function parameters. This has no effect and is almost certainly accidental, so it's in the `correctness` category like `self_assignment`.
This also lays the groundwork for a more generalized version of #5102.
changelog: new lint: [`redundant_local`]
Multibyte character removal in String::pop and String::remove doctests
I think it would be useful to have the doctests for the `String::pop()` and `String::remove()` methods demonstrate that they work on multibyte UTF-8 sequences.
Fix size_hint for EncodeUtf16
More realistic upper and lower bounds, and handle the case where the iterator is located within a surrogate pair.
Resolves#113897
fix docs & example for `std::os::unix::prelude::FileExt::write_at`
Changelog:
* used `File::create` instead of `File::read` to get a writeable file
* explicity mentioned the bug with `pwrite64` in docs
Unfortunately, I don't think that there is really much we can do about this since the feature has already been stabilised.
We could potentially add a clippy lint warning people on Linux that using `write_at` with the `O_APPEND` flag does not exhibit the behaviour that they would have assumed.
fixes#113627
Allow limited access to `OsString` bytes
This extends #109698 to allow no-cost conversion between `Vec<u8>` and `OsString` as suggested in feedback from `os_str_bytes` crate in #111544.
Update the tracking issue for `const_cstr_from_ptr`
Tracking issue #101719 was for `const_cstr_methods`, #113219 is a new issue specific for `const_cstr_from_ptr`.
(I believe #101719 could also be closed)
```@rustbot``` label +T-libs-api +A-docs
Normalize expected ty in call arguments
fix#15321
I'm not sure if we should do this, or add a normalize in the beginning of `infer_expr_inner`, or somewhere else. r? `@lowr`
fix dogfood lints in `redundant_local`
keep `redundant_local` from running in proc macros
rewrite `redundant_local` as late pass
make redundant_local's `find_binding` more readable
pluralize `redundant_locals` name
add test for `redundant_locals` in macros
test `redundant_locals` in proc macros
use more destructuring in `redundant_locals`
fix: format redundant_locals.rs
ignore needless_pass_by_mut_ref in redundant_locals test
New lint [`absolute_paths`]
Closes#10568
Maybe we should make the max segments allowed a configuration option? I see quite a bit of 3-segment paths in clippy, and while I think only really `<mod/type>::<item>` or `<item>` should be (usually) used but anything above may be too widespread 😕
PS, despite this being "max segments allowed" it only lints if it's absolute, as is the point of the lint, e.g., `std::io::ErrorKind::etc` is linted but `io::ErrorKind::NotFound::etc` isn't
changelog: New lint [`absolute_paths`]
[RFC] Support `.comment` section like GCC/Clang (`!llvm.ident`)
Both GCC and Clang write by default a `.comment` section with compiler information:
```txt
$ gcc -c -xc /dev/null && readelf -p '.comment' null.o
String dump of section '.comment':
[ 1] GCC: (GNU) 11.2.0
$ clang -c -xc /dev/null && readelf -p '.comment' null.o
String dump of section '.comment':
[ 1] clang version 14.0.1 (https://github.com/llvm/llvm-project.git c62053979489ccb002efe411c3af059addcb5d7d)
```
They also implement the `-Qn` flag to avoid doing so:
```txt
$ gcc -Qn -c -xc /dev/null && readelf -p '.comment' null.o
readelf: Warning: Section '.comment' was not dumped because it does not exist!
$ clang -Qn -c -xc /dev/null && readelf -p '.comment' null.o
readelf: Warning: Section '.comment' was not dumped because it does not exist!
```
So far, `rustc` only does it for WebAssembly targets and only when debug info is enabled:
```txt
$ echo 'fn main(){}' | rustc --target=wasm32-unknown-unknown --emit=llvm-ir -Cdebuginfo=2 - && grep llvm.ident rust_out.ll
!llvm.ident = !{!27}
```
The RFC part of this PR is about which behavior should `rustc` follow:
- Always add it.
- Add it by default, i.e. have an opt-out flag (GCC, Clang).
- Have an opt-in flag.
- Never add it (current).
There is also the question of whether debug info being enabled matters for that decision, given the current behavior of WebAssembly targets.
For instance, adding it by default gets us closer to other popular compilers, but that may surprise some users with an information leak. The most conservative option is to only do so opt-in, even if debug info is enabled (some users may be stripping debug info and not expecting something else to be leaked elsewhere).
Implementation-wise, this covers both `ModuleLlvm::new()` and `ModuleLlvm::new_metadata()` cases by moving the addition to `context::create_module` and adds a few test cases.
ThinLTO also sees the `llvm.ident` named metadata duplicated (in temporary outputs), so this deduplicates it like it is done for `wasm.custom_sections`. The tests also check this duplication does not take place.
Both GCC and Clang write by default a `.comment` section with compiler
information:
```txt
$ gcc -c -xc /dev/null && readelf -p '.comment' null.o
String dump of section '.comment':
[ 1] GCC: (GNU) 11.2.0
$ clang -c -xc /dev/null && readelf -p '.comment' null.o
String dump of section '.comment':
[ 1] clang version 14.0.1 (https://github.com/llvm/llvm-project.git c62053979489ccb002efe411c3af059addcb5d7d)
```
They also implement the `-Qn` flag to avoid doing so:
```txt
$ gcc -Qn -c -xc /dev/null && readelf -p '.comment' null.o
readelf: Warning: Section '.comment' was not dumped because it does not exist!
$ clang -Qn -c -xc /dev/null && readelf -p '.comment' null.o
readelf: Warning: Section '.comment' was not dumped because it does not exist!
```
So far, `rustc` only does it for WebAssembly targets and only
when debug info is enabled:
```txt
$ echo 'fn main(){}' | rustc --target=wasm32-unknown-unknown --emit=llvm-ir -Cdebuginfo=2 - && grep llvm.ident rust_out.ll
!llvm.ident = !{!27}
```
In the RFC part of this PR it was decided to always add
the information, which gets us closer to other popular compilers.
An opt-out flag like GCC and Clang may be added later on if deemed
necessary.
Implementation-wise, this covers both `ModuleLlvm::new()` and
`ModuleLlvm::new_metadata()` cases by moving the addition to
`context::create_module` and adds a few test cases.
ThinLTO also sees the `llvm.ident` named metadata duplicated (in
temporary outputs), so this deduplicates it like it is done for
`wasm.custom_sections`. The tests also check this duplication does
not take place.
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
