new lint: `only_used_in_recursion`
changed:
- added `only_used_in_recursion`.
- fixed code that variables are only used in recursion.
- this would not lint when `unused_variable`
This fixes: #8390
-----
changelog: add lint [`only_used_in_recursion`]
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`
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
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
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
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
