Add size_of_ref lint
This addresses #9995, which is likely raising a valid point about `std::mem::size_of_val()`: It's [very easy to use double-references as the argument](https://github.com/apache/arrow-datafusion/pull/4371#discussion_r1032385224), which the function will happily accept and give back the size of _the reference_, not the size of the value _behind_ the reference. In the worst case, if the value matches the programmer's expectation, this seems to work, while in fact, everything will go horribly wrong e.g. on a different platform.
The size of a `&T` is independent of what `T` is, and people might want to use `std::mem::size_of_val()` to actually get the size of _any_ reference (e.g. via `&&()`). I would rather suggest that this is always bad behavior, though ([instead](https://doc.rust-lang.org/reference/type-layout.html#pointers-and-references-layout), [and](https://doc.rust-lang.org/stable/std/primitive.usize.html#associatedconstant.BITS)). I, therefore, put this lint into `correctness`.
Since the problem is usually easily fixed by removing extra `&`, I went light on suggesting code.
---
changelog: New lint: [`size_of_ref`]
[#10098](https://github.com/rust-lang/rust-clippy/pull/10098)
<!-- changelog_checked -->
Changelog 1.66
It's really nice to see a changelog with so many suggestion fixes and improvements. Not much else to say. This should be merged with the coming release on 2022-12-15. For the reviewer, please review it and approve it if it looks good. The merge should wait until the release :)
---
changelog: none
<!-- changelog_checked -->
feat: lint unchecked subtraction of a 'Duration' from an 'Instant'
Hello all, I tried to tackle the open issue #9371 and this is what I came up with.
I have a difficulty currently - some tests are failing:
```
failures:
[ui] ui/manual_instant_elapsed.rs
```
The `manual_instant_elapsed` is failing because of `Instant::now() - duration` test, this now gets also picked by `unchecked_duration_subtraction` lint.
What is the correct way to proceed in this case? Simply update the `.stderr` file for `manual_instant_elapsed` lint?
changelog: [`unchecked_duration_subtraction`]: Add lint for unchecked subtraction of a `Duration` from an `Instant`.
fixes#9371
Add `manual_is_ascii_check` lint
Addresses https://github.com/rust-lang/rust-clippy/issues/9290
This PR adds new lint `manual_is_ascii_check`, which detects comparison with ascii ranges using `matches!` macros.
As I mentioned as following in the Issue;
> Yes, that's true. we'll start small and then grow it.
> So I'll try to handle matches! macro with single range as suggested above.
However during writing first version, I was thinking that the changes to support alphabetic and digits will be small patch, so I made a single PR in hope review cost can be reduced.
changelog: add new lint [`manual_is_ascii_check`]
r? `@xFrednet`
Changelog for Rust 1.65
Roses are red,
violets are blue,
another 6 weeks,
another changelog, yahoo!
This did not rhyme,
luckily, not a crime.
I want to say something smart,
but I am out of time.
---
Note for the reviewer. This PR is written, as if Rust was already released on 2022-11-03. Please review the changes and approve if you agree, but only merge it after the release. :)
---
changelog: none
Add lint for confusing use of `^` instead of `.pow`
fixes#4205
Adds a lint named [`confusing_xor_and_pow`], it warns the user when `a ^ b` is used as the `.pow()` function, it doesn't warn for Hex, Binary... etc.
---
changelog: New lint: [`confusing_xor_and_pow`]
add new lint `seek_to_start_instead_of_rewind `
changelog: `seek_to_start_instead_of_rewind`: new lint to suggest using `rewind` instead of `seek` to start
Resolve#8600
Add `unused_format_specs` lint
Currently catches two cases:
An empty precision specifier:
```rust
// the same as {}
println!("{:.}", x);
```
And using formatting specs on `format_args!()`:
```rust
// prints `x.`, not `x .`
println("{:5}.", format_args!("x"));
```
changelog: new lint: [`unused_format_specs`]
Add `manual_filter` lint for `Option`
Share much of its implementation with `manual_map` and should greatly benefit from its previous feedback.
I'm sure it's possible to even more refactor both and would gladly take input on that as well as any clippy idiomatic usage, since this is my first lint addition.
I've added the lint to the complexity section for now, I don't know if every new lint needs to go in nursery first.
The matching could be expanded to more than `Some(<value>)` to lint on arbitrary struct matching inside the `Some` but I've left it like it was for `manual_map` for now. `needless_match::pat_same_as_expr` provides a more generic match example.
close https://github.com/rust-lang/rust-clippy/issues/8822
changelog: Add lint [`manual_filter`] for `Option`
This lint detects calls to a `&self`-taking `as_ptr` method, where
the result is then immediately cast to a `*mut T`. Code like this
is probably invalid, as that pointer will not have write permissions,
and `*mut T` is usually used to write through.
add `box-default` lint
This adds a `box-default` lint to suggest using `Box::default()` instead of `Box::new(Default::default())`, which offers less moving parts and potentially better performance according to [the perf book](https://nnethercote.github.io/perf-book/standard-library-types.html#box).
---
changelog: add [`box_default`] lint
Implement https://github.com/rust-lang/rust-clippy/issues/8368 - a new
lint to inline format arguments such as `print!("{}", var)` into
`print!("{var}")`.
code | suggestion | comment
---|---|---
`print!("{}", var)` | `print!("{var}")` | simple variables
`print!("{0}", var)` | `print!("{var}")` | positional variables
`print!("{v}", v=var)` | `print!("{var}")` | named variables
`print!("{0} {0}", var)` | `print!("{var} {var}")` | aliased variables
`print!("{0:1$}", var, width)` | `print!("{var:width$}")` | width
support
`print!("{0:.1$}", var, prec)` | `print!("{var:.prec$}")` | precision
support
`print!("{:.*}", prec, var)` | `print!("{var:.prec$}")` | asterisk
support
code | suggestion | comment
---|---|---
`print!("{0}={1}", var, 1+2)` | `print!("{var}={0}", 1+2)` | Format
string uses an indexed argument that cannot be inlined. Supporting this
case requires re-indexing of the format string.
changelog: [`uninlined_format_args`]: A new lint to inline format
arguments, i.e. `print!("{}", var)` into `print!("{var}")`
This is done because `to_owned` is very similarly named to `into_owned`, but the
effect of calling those two methods is completely different. This creates
confusion (stemming from the ambiguity of the 'owned' term in the context of
`Cow`s) and might not be what the writer intended.
new lint
This fixes#6576
If you added a new lint, here's a checklist for things that will be
checked during review or continuous integration.
- \[x] Followed [lint naming conventions][lint_naming]
- \[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: add [`multi_assignments`] lint
Lint `collapsible_str_replace`
fixes#6651
```
changelog: [`collapsible_str_replace`]: create new lint `collapsible_str_replace`
```
If you added a new lint, here's a checklist for things that will be
checked during review or continuous integration.
- \[x] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[ ] Executed `cargo dev update_lints`
- \[x] Added lint documentation
- \[x] Run `cargo dev fmt`
Add new lint [`positional_named_format_parameters`]
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: Add new lint [`positional_named_format_parameters`] to warn when named parameters in format strings are used as positional arguments.
Add lint recommending using `std::iter::once` and `std::iter::empty`
```
changelog: [`iter_once`]: add new lint
changelog: [`iter_empty`]: add new lint
```
fixes#9186
- \[ ] Followed [lint naming conventions][lint_naming]
- \[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`
[lint_naming]: https://rust-lang.github.io/rfcs/0344-conventions-galore.html#lints
The lint doesn't really follow the naming conventions. I don't have any better idea so I'm open to suggestions.
Add partialeq_to_none lint
Initial implementation of #9275, adding lint `partialeq_to_none`. This is my first time working on `clippy`, so please review carefully.
I'm unsure especially about the `Sugg`, as it covers the entire `BinOp`, instead of just covering one of the sides and the operator (see the multi-line example). I was unsure if pinpointing the suggestion wouldn't be brittle...
changelog: [`PARTIALEQ_TO_NONE`]: Initial commit
Add new lint `obfuscated_if_else`
part of #9100, additional commits could make it work with `then` and `unwrap_or_else` as well
changelog: Add new lint `obfuscated_if_else`
Changelog for Rust 1.62 🦖
This special artifact was just discovered. The artifact details changes to something called Clippy. Presently and from the context, we were unable to determine what this is supposed to be. All we know, is that it seems to have an active community around it which supports it. The members sometimes use paper clips as a secret symbol for Clippy.
I want to donate this artifact to the rust-lang organization, to have it displayed to the public.
---
changelog: none
add [`manual_find`] lint for function return case
part of the implementation discussed in #7143
changelog: add [`manual_find`] lint for function return case
Update description in clippy_lints/src/default_iter_empty.rs
Co-authored-by: Fridtjof Stoldt <xFrednet@gmail.com>
Update clippy_lints/src/default_iter_empty.rs
Co-authored-by: Alex Macleod <alex@macleod.io>
Update clippy_lints/src/default_iter_empty.rs
Co-authored-by: Alex Macleod <alex@macleod.io>
renamed default_iter_empty to default_instead_of_iter_empty
Avoid duplicate messages
add tests for regression
rewrite 'Why is this bad?'
cargo dev fmt
delete default_iter_empty lint in renamed_lint.rs
rewrite a message in the suggestion
cargo dev update_lints --check
new lint: `borrow_deref_ref`
changelog: ``[`borrow_deref_ref`]``
Related pr: #6837#7577
`@Jarcho` Could you please give a review?
`cargo lintcheck` gives no false negative (but tested crates are out-of-date).
TODO:
1. Not sure the name. `deref_on_immutable_ref` or some others?
Mini changelog update for Rust 1.61.0
I'll do the full release and sync tomorrow, as I sadly don't have the time today. This is a quick update to ensure that Rust's changelog will link to the correct section in our changelog. The change is according to [our docs](8751e47bae/book/src/development/infrastructure/release.md (update-changelogmd))
changelog: none
New lint: [`derive_partial_eq_without_eq`]
Introduces a new lint, [`derive_partial_eq_without_eq`].
See: #1781 (doesn't close it though).
changelog: add lint [`derive_partial_eq_without_eq`]
Take over: New lint bytes count to len
take over #8375close#8083
This PR adds new lint about considering replacing `.bytes().count()` with `.len()`.
Thank you in advance.
---
r! `@Manishearth`
changelog: adds new lint [`bytes_count_to_len`] to consider replacing `.bytes().count()` with `.len()`
Add `await_holding_invalid_type` lint
changelog: [`await_holding_invalid_type`]
This lint allows users to create a denylist of types which are not allowed to be
held across await points. This is essentially a re-implementation of the
language-level [`must_not_suspend`
lint](https://github.com/rust-lang/rust/issues/83310). That lint has a lot of
work still to be done before it will reach Rust stable, and in the meantime
there are a lot of types which can trip up developers if they are used
improperly.
I originally implemented this specifically for `tracing::span::Entered`, until I discovered #8434 and read the commentary on that PR. Given this implementation is fully user configurable, doesn't tie clippy to any one particular crate, and introduces no additional dependencies, it seems more appropriate.
changelog: [`await_holding_invalid_type`]
This lint allows users to create a denylist of types which are not allowed to be
held across await points. This is essentially a re-implementation of the
language-level [`must_not_suspend`
lint](https://github.com/rust-lang/rust/issues/83310). That lint has a lot of
work still to be done before it will reach Rust stable, and in the meantime
there are a lot of types which can trip up developers if they are used
improperly.
This lint checks if Option::take() is used on a temporary value (a value
that is not of type &mut Option and that is not a Place expression) to
suggest omitting take()
New lint `is_digit_ascii_radix`
Closes#6399
changelog: Added [`is_digit_ascii_radix`]: recommend `is_ascii_digit()` or `is_ascii_hexdigit()` in place of `is_digit(10)` and `is_digit(16)`
Add `crate_in_macro_def` lint
This PR adds a lint to check for `crate` as opposed to `$crate` used in a macro definition.
I think this can close#4798. That issue focused on the case where the macro author "imports something into said macro."
But I think use of `crate` is likely to be a bug whether it appears in a `use` statement or not. There could be some use case I am failing to see, though. (cc: `@nilscript` `@flip1995)`
changelog: `crate_in_macro_def`
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.
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`
