Llint for casting between raw slice pointers with different element sizes
This lint disallows using `as` to convert from a raw pointer to a slice (e.g. `*const [i32]`, `*mut [Foo]`) to any other raw pointer to a slice if the element types have different sizes. When a raw slice pointer is cast, the data pointer and count metadata are preserved. This means that when the size of the inner slice's element type changes, the total number of bytes pointed to by the count changes. For example a `*const [i32]` with length 4 (four `i32` elements) is cast `as *const [u8]` the resulting pointer points to four `u8` elements at the same address, losing most of the data. When the size *increases* the resulting pointer will point to *more* data, and accessing that data will be UB.
On its own, *producing* the pointer isn't actually a problem, but because any use of the pointer as a slice will either produce surprising behavior or cause UB I believe this is a correctness lint. If the pointer is not intended to be used as a slice, the user should instead use any of a number of methods to produce just a data pointer including an `as` cast to a thin pointer (e.g. `p as *const i32`) or if the pointer is being created from a slice, the `as_ptr` method on slices. Detecting the intended use of the pointer is outside the scope of this lint, but I believe this lint will also lead users to realize that a slice pointer is only for slices.
There is an exception to this lint when either of the slice element types are zero sized (e.g `*mut [()]`). The total number of bytes pointed to by the slice with a zero sized element is zero. In that case preserving the length metadata is likely intended as a workaround to get the length metadata of a slice pointer though a zero sized slice.
The lint does not forbid casting pointers to slices with the *same* element size as the cast was likely intended to reinterpret the data in the slice as some equivalently sized data and the resulting pointer will behave as intended.
---
changelog: Added ``[`cast_slice_different_sizes`]``, a lint that disallows using `as`-casts to convert between raw pointers to slices when the elements have different sizes.
Only point at the end of the crate. We could try making it point at the
beginning of the crate, but that is confused with `DUMMY_SP`, causing
the output to be *worse*.
This change will make it so that VSCode will *not* underline the whole
file when `main` is missing, so other errors will be visible.
Add lint to detect `allow` attributes without reason
I was considering putting this lint into the pedantic group. However, that would result in countless warnings for existing projects. Having it in restriction also seems good to me 🙃 (And now I need sleep 💤 )
---
changelog: New lint [`allow_lint_without_reason`] (Requires the `lint_reasons` feature)
Closes: rust-lang/rust-clippy#8502
Add `unnecessary_find_map` lint
This PR adds an `unnecessary_find_map` lint. It is essentially just a minor enhancement of `unnecessary_filter_map`.
Closes#8467
changelog: New lint `unnecessary_find_map`
new lint: `missing-spin-loop`
This fixes#7809. I went with the shorter name because the function is called `std::hint::spin_loop`. It doesn't yet detect `while let` loops. I left that for a follow-up PR.
---
changelog: new lint: [`missing_spin_loop`]
This internal lint checks if the `extract_msrv_attrs!` macro is used if
a lint has a MSRV. If not, it suggests to add this attribute to the lint
pass implementation.
fix false positives of large_enum_variant
fixes: #8321
The size of enums containing generic type was calculated to be 0.
I changed [large_enum_variant] so that such enums are not linted.
changelog: none
tests: default to more threads for ui-tests
Benchmarks (tested on i5-7200U, 2 cores, 4 threads)
```
master branch:
cargo test // prime caches
cargo --color=always test 70,39s user 21,91s system 180% cpu 51,035 total
cargo --color=always test 70,77s user 22,13s system 180% cpu 51,579 total
cargo --color=always test 70,97s user 22,12s system 180% cpu 51,673 total
cargo --color=always nextest run 78,74s user 22,27s system 220% cpu 45,829 total
cargo --color=always nextest run 78,46s user 21,92s system 224% cpu 44,674 total
cargo --color=always nextest run 78,31s user 22,21s system 228% cpu 43,909 total
Patched (ui_speedup branch):
cargo test // prime cache
cargo --color=always test 97,51s user 32,02s system 288% cpu 44,905 total
cargo --color=always test 99,19s user 31,91s system 276% cpu 47,436 total
cargo --color=always test 98,47s user 31,84s system 284% cpu 45,744 total
cargo --color=always nextest run 102,18s user 30,80s system 350% cpu 37,902 total
cargo --color=always nextest run 99,75s user 29,86s system 350% cpu 36,935 total
cargo --color=always nextest run 100,36s user 29,93s system 351% cpu 37,061 total
```
changelog: use more threads for running clippys ui-tests for ~10% walltime speedup
Don't lint `match` expressions with `cfg`ed arms
Somehow there are no open issues related to this for any of the affected lints. At least none that I could fine from a quick search.
changelog: Don't lint `match` expressions with `cfg`ed arms in many cases
Benchmarks (tested on i5-7200U, 2 core 4 threads)
```
master branch:
cargo test // prime caches
cargo --color=always test 70,39s user 21,91s system 180% cpu 51,035 total
cargo --color=always test 70,77s user 22,13s system 180% cpu 51,579 total
cargo --color=always test 70,97s user 22,12s system 180% cpu 51,673 total
cargo --color=always nextest run 78,74s user 22,27s system 220% cpu 45,829 total
cargo --color=always nextest run 78,46s user 21,92s system 224% cpu 44,674 total
cargo --color=always nextest run 78,31s user 22,21s system 228% cpu 43,909 total
Patched (ui_speedup branch)
cargo test // prime cache
cargo --color=always test 97,51s user 32,02s system 288% cpu 44,905 total
cargo --color=always test 99,19s user 31,91s system 276% cpu 47,436 total
cargo --color=always test 98,47s user 31,84s system 284% cpu 45,744 total
cargo --color=always nextest run 102,18s user 30,80s system 350% cpu 37,902 total
cargo --color=always nextest run 99,75s user 29,86s system 350% cpu 36,935 total
cargo --color=always nextest run 100,36s user 29,93s system 351% cpu 37,061 total
```
Fix `await_holding_lock` not linting `parking_lot` Mutex/RwLock
This adds tests for `RwLock` and `parking_lot::{Mutex, RwLock}`, which were added before in 2dc8c083f5, but never tested in UI tests. I noticed this while reading [fasterthanli.me](https://fasterthanli.me/articles/a-rust-match-made-in-hell) latest blog post, complaining that Clippy doesn't catch this for `parking_lot`. (Too many people read his blog, he's too powerful)
Some more things:
- Adds a test for #6446
- Improves the lint message
changelog: [`await_holding_lock`]: Now also lints for `parking_lot::{Mutex, RwLock}`
Improve `redundant_slicing` lint
fixes#7972fixes#7257
This can supersede #7976
changelog: Fix suggestion for `redundant_slicing` when re-borrowing for a method call
changelog: New lint `deref_as_slicing`
Don't lint `needless_borrow` in method receiver positions
fixes#8408fixes#8407fixes#8391fixes#8367fixes#8380
This is a temporary fix for `needless_borrow`. The proper fix is included in #8355.
This should probably be merged into rustc before beta branches on Friday. This issue has been reported six or seven times in the past couple of weeks.
changelog: Fix various issues with `needless_borrow` n´. Note to changelog writer: those issues might have been introduced in this release cycle, so this might not matter in the changelog.
Don't lint Default::default if it is the udpate syntax base
changelog: Don't lint `Default::default` it is part of the update syntax
Current clippy warns about this:
```
warning: calling `Foo::default()` is more clear than this expression
--> src/main.rs:12:11
|
12 | ..Default::default()
| ^^^^^^^^^^^^^^^^^^ help: try: `Foo::default()`
|
```
With these changes, it will not lint that particular expression anymore.
The to_string_in_display lint is renamed to recursive_format_impl
A check is added for the use of self formatted with Display or Debug
inside any format string in the same impl
The to_string_in_display check is kept as is - like in the
format_in_format_args lint
For now only Display and Debug are checked
This could also be extended to other Format traits (Binary, etc.)
Fix `transmute_undefined_repr` with single field `#[repr(C)]` structs
Fixes: #8417
The description has also been made more precise.
changelog: Fix `transmute_undefined_repr` with single field `#[repr(C)]` structs
changelog: Move `transmute_undefined_repr` back to `correctness`
Support `cargo dev bless` for tests with revisions
changelog: internal: Support `cargo dev bless` for tests with revisions
Previously bless wouldn't pick up the saved stderr from `target/debug/tests/manual_assert.stage-id.edition2021.stderr` or `target/debug/tests/manual_assert.stage-id.edition2018.stderr` due to there being multiple revisions of the test output
This tweaks compile-test so the built files end up in e.g. `target/debug/tests/ui`, `target/debug/tests/ui-cargo` rather than share the `tests` dir. `cargo dev bless` then uses that to update all the `.stdout/stdout/fixed` files it can find
Also removes an empty file I found, and the logic to remove empty outputs as compiletest doesn't produce empty `.stdout/stderr` files
warn if we find multiple clippy configs
Fixes#8323
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: warn if we find multiple clippy configs
Add lint `transmute_undefined_repr`
Partially implements #3999 and #546
This doesn't consider `enum`s at all right now as those are going to be a pain to deal with. This also allows `#[repr(Rust)]` structs with only one non-zero sized fields. I think those are technically undefined when transmuted.
changelog: Add lint `transmute_undefined_repr`
Add `explicit_write` suggestions for `write!`s with format args
changelog: Add [`explicit_write`] suggestions for `write!`s with format args
Fixes#4542
```rust
writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
```
Now suggests:
```
error: use of `writeln!(stderr(), ...).unwrap()`
--> $DIR/explicit_write.rs:36:9
|
LL | writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `eprintln!("macro arg {}", one!())`
```
---------
r? `@camsteffen` (again, sorry 😛) for the `FormatArgsExpn` change
Before this change `inputs_span` returned a span pointing to just `1` in
```rust
macro_rules! one {
() => { 1 };
}
`writeln!(std::io::stderr(), "macro arg {}", one!()).unwrap();`
```
And the `source_callsite` of that span didn't include the format string, it was just `one!()`
make unwrap_used also trigger on .get().unwrap()
fixes#8124
changelog: make the [unwrap_used] lint trigger for code of the form such as `.get(i).unwrap()` and `.get_mut(i).unwrap()`
[explicit_counter_loop] suggests `.into_iter()`, despite that triggering [into_iter_on_ref] in some cases
I have modified `fn make_iterator_snippet` in clippy_lints/src/loops/utils.rs ,so this change has some little influence on another lint [manual_flatten] .
fixes#8155
---
changelog: Fix that [`explicit_counter_loop`] suggests `into_iter()` despite that triggering [`into_iter_on_ref`] in some cases
single_match: Don't lint non-exhaustive matches; support tuples
`single_match` lint:
* Don't lint exhaustive enum patterns without a wild.
Rationale: The definition of the enum could be changed, so the user can get non-exhaustive match after applying the suggested lint (see https://github.com/rust-lang/rust-clippy/issues/8282#issuecomment-1013566068 for context).
* Lint `match` constructions with tuples (as suggested at https://github.com/rust-lang/rust-clippy/issues/8282#issuecomment-1015621148)
Closes#8282
---
changelog: [`single_match`]: Don't lint exhaustive enum patterns without a wild.
changelog: [`single_match`]: Lint `match` constructions with tuples
Fix underflow in `manual_split_once` lint
Hi, a friend found clippy started crashing on a suspiciously large allocation of `u64::MAX` memory on their code.
The mostly minimized repro is:
```rust
fn _f01(title: &str) -> Option<()> {
let _ = title[1..].splitn(2, '[').next()?;
Some(())
}
```
The underflow happens in this case on line 57 of the patch but I've changed the other substraction to saturating as well since it could potentially cause the same issue.
I'm not sure where to put a regression test, or if it's even worth for such a thing.
Aside, has it been considered before to build clippy with overflow checks enabled?
changelog: fix ICE of underflow in `manual_split_once` lint
Fix `needless_borrow` causing mutable borrows to be moved
fixes#8191
changelog: Fix `needless_borrow` causing mutable borrows to be moved
changelog: Rename `ref_in_deref` to `needless_borrow`
changelog: Suggest removing the borrow on method call receivers in `needless_borrow`
Check usages in `ptr_arg`
fixes#214fixes#1981fixes#3381fixes#6406fixes#6964
This does not take into account the return type of the function currently, so `(&Vec<_>) -> &Vec<_>` functions may still be false positives.
The name given for the type also has to match the real type name, so `type Foo = Vec<u32>` won't trigger the lint, but `type Vec = Vec<u32>` will. I'm not sure if this is the best way to handle this, or if a note about the actual type should be added instead.
changelog: Check if the argument is used in a way which requires the original type in `ptr_arg`
changelog: Lint mutable references in `ptr_arg`
This commit changes the behavior of `single_match` lint.
After that, we won't lint non-exhaustive matches like this:
```rust
match Some(v) {
Some(a) => println!("${:?}", a),
None => {},
}
```
The rationale is that, because the type of `a` could be changed, so the
user can get non-exhaustive match after applying the suggested lint (see
https://github.com/rust-lang/rust-clippy/issues/8282#issuecomment-1013566068
for context).
We also will lint `match` constructions with tuples. When we see the
tuples on the both arms, we will check them both at the same time, and
if they form exhaustive match, we could display the warning.
Closes#8282
Add `msrv` config for `map_clone`
Just a small PR to have some fun with Clippy and to clear my head a bit 😅
---
changelog: [`map_clone`]: The suggestion takes `msrv` into account
changelog: Track `msrv` attribute for `manual_bits` and `borrow_as_prt`
fixes: #8276
fix op_ref false positive
fixes#7572
changelog: `op_ref` don't lint for unnecessary reference in BinOp impl if removing the reference will lead to unconditional recursion
issue #8239: Printed hint for lint or_fun_call is cropped and does no…
fixesrust-lang/rust-clippy#8239
changelog: [`or_fun_call`]: if suggestion contains more lines than MAX_SUGGESTION_HIGHLIGHT_LINES it is stripped to one line
* Track the argument when used to initialize simple `let` bindings
* Check if the argument is passed to a function requiring the original type
* Use `multipart_suggestion` rather than multiple suggestions
* Check if the name given in the source code matches the name of the actual type
`manual_memcpy` fix
fixes#8160
Ideally this would work with `VecDeque`, but the current interface is unsuitable for it. At a minimum something like `range_as_slices` would be needed.
changelog: Don't lint `manual_memcpy` on `VecDeque`
changelog: Suggest `copy_from_slice` for `manual_memcpy` when applicable
Some test code cleanup
changelog: none
Mainly moves /clippy_workspace_tests into /tests and combines the two dogfood tests which can't run concurrently.
This pull request adds a lint against single character lifetime names, as they might not divulge enough information about the purpose of the lifetime. This can make code harder to understand. I placed this in `restriction` rather than `pedantic` (as suggested in #8233) since most of the Rust ecosystem already uses single character lifetime names (to my knowledge, at least) and since single character lifetime names aren't incorrect. I'd be happy to change this upon request, however. Fixes#8233.
- [x] Followed lint naming conventions
- [x] Added passing UI tests (including committed `.stderr` file)
- [x] `cargo test` passes locally
- [x] Executed `cargo dev update_lints`
- [x] Added lint documentation
- [x] Run `cargo dev fmt`
changelog: new lint: [`single_char_lifetime_names`]
Better detect when a field can be moved from in `while_let_on_iterator`
fixes#8113
changelog: Better detect when a field can be moved from in `while_let_on_iterator`
Fix `type_repetition_in_bounds`
fixes#7360fixes#8162fixes#8056
changelog: Check for full equality in `type_repetition_in_bounds` rather than just equal hashes
New macro utils
changelog: none
Sorry, this is a big one. A lot of interrelated changes and I wanted to put the new utils to use to make sure they are somewhat battle-tested. We may want to divide some of the lint-specific refactoring commits into batches for smaller reviewing tasks. I could also split into more PRs.
Introduces a bunch of new utils at `clippy_utils::macros::...`. Please read through the docs and give any feedback! I'm happy to introduce `MacroCall` and various functions to retrieve an instance. It feels like the missing puzzle piece. I'm also introducing `ExpnId` from rustc as "useful for Clippy too". `@rust-lang/clippy`
Fixes#7843 by not parsing every node of macro implementations, at least the major offenders.
I probably want to get rid of `is_expn_of` at some point.
changelog: none
Sorry, this is a big one. A lot of interrelated changes and I wanted to put the new utils to use to make sure they are somewhat battle-tested. We may want to divide some of the lint-specific refactoring commits into batches for smaller reviewing tasks. I could also split into more PRs.
Introduces a bunch of new utils at `clippy_utils::macros::...`. Please read through the docs and give any feedback! I'm happy to introduce `MacroCall` and various functions to retrieve an instance. It feels like the missing puzzle piece. I'm also introducing `ExpnId` from rustc as "useful for Clippy too". `@rust-lang/clippy`
Fixes#7843 by not parsing every node of macro implementations, at least the major offenders.
I probably want to get rid of `is_expn_of` at some point.
wrong_self_convention: Match `SelfKind::No` more restrictively
The `wrong_self_convention` lint uses a `SelfKind` type to decide
whether a method has the right kind of "self" for its name, or whether
the kind of "self" it has makes its name confusable for a method in
a common trait. One possibility is `SelfKind::No`, which is supposed
to mean "No `self`".
Previously, SelfKind::No matched everything _except_ Self, including
references to Self. This patch changes it to match Self, &Self, &mut
Self, Box<Self>, and so on.
For example, this kind of method was allowed before:
```
impl S {
// Should trigger the lint, because
// "methods called `is_*` usually take `self` by reference or no `self`"
fn is_foo(&mut self) -> bool { todo!() }
}
```
But since SelfKind::No matched "&mut self", no lint was triggered
(see #8142).
With this patch, the code above now gives a lint as expected.
fixes#8142
changelog: [`wrong_self_convention`] rejects `self` references in more cases
Inspired by a discussion in rust-lang/rust-clippy#8197
---
r? `@llogiq`
changelog: none
The lint is this on nightly, therefore no changelog entry for you xD
The `wrong_self_convention` lint uses a `SelfKind` type to decide
whether a method has the right kind of "self" for its name, or whether
the kind of "self" it has makes its name confusable for a method in
a common trait. One possibility is `SelfKind::No`, which is supposed
to mean "No `self`".
Previously, SelfKind::No matched everything _except_ Self, including
references to Self. This patch changes it to match Self, &Self, &mut
Self, Box<Self>, and so on.
For example, this kind of method was allowed before:
```
impl S {
// Should trigger the lint, because
// "methods called `is_*` usually take `self` by reference or no `self`"
fn is_foo(&mut self) -> bool { todo!() }
}
```
But since SelfKind::No matched "&mut self", no lint was triggered
(see #8142).
With this patch, the code above now gives a lint as expected.
Fixes#8142
changelog: [`wrong_self_convention`] rejects `self` references in more cases
This improves the quality of the genrated output and makes it
more in line with other lint messages.
changelog: [`unused_io_amount`]: Improve help text
Clippy helpfully warns about code like this, telling you that you
probably meant "write_all":
fn say_hi<W:Write>(w: &mut W) {
w.write(b"hello").unwrap();
}
This patch attempts to extend the lint so it also covers this
case:
async fn say_hi<W:AsyncWrite>(w: &mut W) {
w.write(b"hello").await.unwrap();
}
(I've run into this second case several times in my own programming,
and so have my coworkers, so unless we're especially accident-prone
in this area, it's probably worth addressing?)
This patch covers the Async{Read,Write}Ext traits in futures-rs,
and in tokio, since both are quite widely used.
changelog: [`unused_io_amount`] now supports AsyncReadExt and AsyncWriteExt.
