Suggest `Option<&T>` instead of `&Option<T>`
closes#13054
```rust
// bad code
fn foo(a: &Option<T>) {}
fn bar(&self) -> &Option<T> {}
// Use instead
fn foo(a: Option<&T>) {}
fn bar(&self) -> Option<&T> {}
```
Handles argument types and return types in functions, methods, and closures with explicit types. Honors `avoid_breaking_exported_api` parameter.
See this great [YouTube video](https://www.youtube.com/watch?v=6c7pZYP_iIE) with the in-depth explanation.
### Open Questions
These are not blocking, and could be done in separate PRs if needed.
* [ ] Should `&Option<Box<T>>` be suggested as `Option<&T>` -- without the box? Handled by [clippy::borrowed_box](https://rust-lang.github.io/rust-clippy/master/index.html#/borrowed_box)
* [ ] Should `&Option<String>` be suggested as `Option<&str>` -- using de-refed type?
### Possible Future Improvements
These cases might also be good to handle, probably in a separate PR.
```rust
fn lambdas() {
let x = |a: &Option<String>| {};
let x = |a: &Option<String>| -> &Option<String> { todo!() };
}
fn mut_ref_to_ref(a: &mut &Option<u8>) {}
```
changelog: [`ref_option`]: Suggest `Option<&T>` instead of `&Option<T>`
On implicit `Sized` bound on fn argument, point at type instead of pattern
Instead of
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:20
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^ doesn't have a size known at compile-time
```
output
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:29
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
```
Instead of
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:20
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^ doesn't have a size known at compile-time
```
output
```
error[E0277]: the size for values of type `(dyn ThriftService<(), AssocType = _> + 'static)` cannot be known at compilation time
--> $DIR/issue-59324.rs:23:29
|
LL | fn with_factory<H>(factory: dyn ThriftService<()>) {}
| ^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
```
Lint comparison to empty slice using `PartialEq` methods
changelog: [`comparison_to_empty`]: Also detect comparaisons using `PartialEq` methods
Fix#13401
Use contiguous spans for empty_line_after_* suggestion
Replacing an empty span (which an empty line is) with an empty string triggers a debug assertion in rustc. This fixes the debug assertion by using contiguous spans, with the same resulting suggestion.
r? `@Alexendoo`
This unblocks the sync
changelog: none
Replacing an empty span (which an empty line is) with an empty string triggers a
debug assertion in rustc. This fixes the debug assertion by using contiguous
spans, with the same resulting suggestion.
Unused trait imports (formerly anonymous trait import)
For #11969
I'm looking for help and feedback on implementing a new lint for suggesting `use ... as _` for traits where possible.
I have had a go at implementing this but I don't know if this is the best way to do it as I am new to clippy.
There are some edge cases I can think of where this doesn't work but have aired on the side of false negatives instead of false positives.
An example of a false negative. I couldn't figure out the best way to resolve an import from within clippy. The sub module imports MyAny so that cannot be anonymized but `use std::any::Any` could be. In this case it is not caught because `Any` and `MyAny` have the same DefId.
```rust
mod nested_mod_used_bad1 {
use std::any::Any;
use std::any::Any as MyAny;
mod foo {
use crate::nested_mod_used_bad1::MyAny;
fn foo() {
println!("{:?}", MyAny::type_id("foo"));
}
}
}
```
Any feedback is much appreciated.
-------
changelog: new lint: `unused_trait_names`
Fix `if_then_some_else_none` sugg missing closure intro
Fixes#13407#13407 works in current stable. The suggestion-generating code got trampled over in 0532104247 :-)
changelog: [`if_then_some_else_none`]: Fix missing closure in suggestion
[`missing_panics_doc`] Fix#13381Fix#13381
Makes `missing_panics_doc` act like other "panicking" lints (`unwrap_used`, `panic`, etc) in constant environments.
changelog: Ignore `missing_panics_doc` in constant environments
fix: Fixed incorrect comment form suggestion for too_long_first_doc_paragraph lint
fixes#13309
changelog: none
Comment form is now a variable and a new test for too_long_first_doc_paragraph was added.
chore: Ran cargo dev fmt
chore: Fixed spacing
fix: Fixed spacing for comment suggestion
fix: Added new module level test to too_long_first_doc_paragraph
chore: Ran cargo uibless
`needless_pass_by_value` sometimes suggest marking the concerned type as
`Copy`. Adding a `or` before this suggestion makes it clearer that this
is not the second part of the original suggestion, but an alternative one.
Not trigger `duplicated_attributes` on duplicate reasons
As at #13355 we shoudn't trigger `duplicated_attributes` on duplicate reasons attr
changelog: [`duplicated_attributes`]: not trigger `duplicated_attributes` on duplicate reasons
Special-case suggestions for null pointers constness cast
This implements the suggestions from #13361. It fits into the existing `ptr_cast_constness` lint, as this is a specialized version. However,
1. I have not modified the lint MSRV, so the documentation for this lint will still show that it applies only from Rust 1.72.0. This is true in the general case, but the lint for null pointers will trigger even before this version as `null()` and `null_mut()` were already present in Rust 1.0 and there is no reason not to apply this lint. I guess this is only a minor documentation issue that can be ignored.
2. I have not covered the `core::ptr::null::<T>().cast_mut()` (could be made into `core::ptr::null_mut::<T>()`) and `cotr::ptr::null_mut::<T>().cast_const()` (could be made into `core::ptr::null::<T>()`) cases. Should they be covered? If they should, here or in a separate PR?
changelog: [`ptr_cast_constness`]: special-case suggestions for null pointers constness cast
Fix#13361
Bump ui_test
This should give a bunch of ui improvements when lots of tests are running. Please lmk of any issues with it. Switching to `--quiet` should always avoid any issues, so there's a workaround if anything crops up. Also please check that this does not regress performance for you. It doesn't for me, but that doesn't mean much.
changelog: none
Visit struct fields recursively in uninit fallback check
This makes the fallback a bit more consistent with the other checks and rustc.
Fixes#13364. When using a generic type as the `Vec` element type like the issue title says, rustc's uninit check fails and our fallback is used, which didn't look at struct fields when it could.
changelog: none
[`single_match`, `single_match_else`] fix suggestion when match irrefutable
fixes#13012
changelog:[`single_match`, `single_match_else`]: fix suggestion when `match` irrefutable
Extend `implicit_saturating_sub` lint
Fixes#10070.
It can serve as base if we want to add equivalent checks for other arithmetic operations.
Also one important note: when writing this lint, I realized that I could check for wrong conditions performed beforehand on subtraction and added another part in the lint. Considering they both rely on the same checks, I kept both in the same place. Not sure if it makes sense though...
changelog: Extend `implicit_saturating_sub` lint
Use `is_diagnostic_item` for checking a def_id in `unnecessary_min_or_max`.
close#13191
This PR fixes the false positives in `unnecessary_min_or_max `.
We should use `is_diagnostic_item` for checking def_ids in this lint.
----
changelog: fix false positive in `unnecessary_min_or_max `.
Add new lint: `used_underscore_items`
Closes#13260
---
changelog: new [`used_underscore_items`] lint against using items with a single leading underscore
Fix manual_range_patterns case with one element at OR
Close#11825
As mentioned #11825 `OR` can be used for stylistic purposes with one element, we can filter this case from triggering lint
changelog: [`manual_range_patterns`]: not trigger when `OR` has only one element
check std::panic::panic_any in panic lint
close#13292
This PR detects `std::panic::panic_any` in panic lint.
changelog: check std::panic::panic_any in panic lint
Rewrite `empty_line_after_doc_comments` and `empty_line_after_outer_attr`, move them from `nursery` to `suspicious`
changelog: [`empty_line_after_doc_comments`], [`empty_line_after_outer_attr`]: rewrite and move them from `nursery` to `suspicious`
They now lint when there's a comment between the last attr/doc comment and the empty line, to cover the case:
```rust
/// Docs for `old_code
// fn old_code() {}
fn new_code() {}
```
When these lints or `suspicious_doc_comments` trigger we no longer trigger any other doc lint as a broad fix for #12917, reverts some of #13002 as the empty line lints cover it
I ended up not doing https://github.com/rust-lang/rust-clippy/issues/12917#issuecomment-2161828859 as I don't think it's needed
Ignore underscore-prefixed args for needless_pass_by_value lint
When a user explicitly tags a param as unused (yet?), there is no need to raise another lint on it.
fixes#7295
Note that I had to rename all `_*` params in the tests, but kept the variable name length to avoid extra changes in the expected output.
changelog: [`needless_pass_by_value`]: do not warn if the argument name starts with an `_`
Diverging subexpression lint should not fire on todo!()
As per #10243 it is not that helpful to point out that a subexpression diverges, so do not fire on todo
changelog: [`diverging_sub_expression`]: do not trigger on todo
Fix confusing message in double_must_use lint
Close#13003
As mentioned at #13003 it isn't quite clear what it means "an empty `#[must_use]` attribute" so clarify it
changelog: [none]
Trigger [`string_slice`] if expression is reference to `&str`
Close#12708
changelog: [`string_slice`]: trigger lint if expression is reference to `&str`
fix false positive in explicit_iter_loop with msrv
close#13184
This PR fix false positive in explicit_iter_loop when msrv < 1.80
changelog: fix false positive in explicit_iter_loop when msrv < 1.80
Clarify suggestion message for unwrap lint
Close#10217
As mentioned at #10217 message for `unwrap` uses `..` like `Some(..)` which can confuse with slice and other places mostly use `<item>` like `for (i, <item>) in target_groups_json.iter().enumerate().skip(1) {` So replace `..` to `<item>`
changelog: [`unnecessary_unwrap`] clarify suggestion message
Add a test for ice-3717.rs
this PR is a part of https://github.com/rust-lang/rust-clippy/issues/13099.
Based on the changes introduced in #13098 for introduce ui_test, we will update the uitest output.
This is a fix for `ice-3717.rs`.
Although fixes have already been made in #13216, it seems that he is a first-time contributor.
I thought it might be better for him to refer to my PR, so I created it accordingly.
Since this is my first contribution in a while, please let me know if there are any issues or required changes.
changelog: none
r! `@flip1995`
Replace `rustc_semver` with `rustc_session::RustcVersion`
Allows dropping a dependency but there is a behaviour change here, the following versions are no longer accepted:
* `1` (would need to be `1.0` or `1.0.0`)
* `1.0.0-alpha`
* `1.0.0-alpha.2`
* `1.0.0-beta`
But this seems unlikely to effect anybody, I did some GitHub searching and found no occurrences outside our UI tests
r? `@flip1995`
changelog: none
Apply "polymorphization at home" to RawVec
The idea here is to move all the logic in RawVec into functions with explicit size and alignment parameters. This should eliminate all the fussing about how tweaking RawVec code produces large swings in compile times.
This uncovered https://github.com/rust-lang/rust-clippy/issues/12979, so I've modified the relevant test in a way that tries to preserve the spirit of the test without tripping the ICE.
Fix case where doc_markdown is triggered on words ending with "ified"
Fixes#13097.
r? `@Alexendoo`
changelog: Fix case where doc_markdown is triggered on words ending with "ified"
[`macro_metavars_in_unsafe`]: recognize metavariables in tail expressions
Fixes#13219
`macro_metavars_in_unsafe` keeps track of the current "expansion depth" (incremented/decremented when entering/leaving a macro span) to tell if an expression from the root context is contained within a macro (see the doc comment I added for a hopefully better explanation)
Before this PR, we didn't increment said `expn_depth` for `unsafe` blocks within macros, because we already do that in `visit_stmt` anyway, so it would work fine for statements, but that's not enough for tail expressions of an unsafe block.
So we now also increment it for macro unsafe blocks.
Also updated the comment for `expn_depth` while I'm at it because "This is not necessary for correctness" isn't correct now that I think about it
------
changelog: none
Respect allow `inconsistent_struct_constructor` on the struct definition
Closes#13203
Now we check if the target type is marked with `#[allow(clippy:inconsistent_struct_constructor)]` before lining.
As a side-effect of this change, The rule in the subject no longer runs on non-local `AdtDef`s. However, as suggested by `@Jarcho` it shouldn't be a big deal since most of the time we didn't have access to this information anyway.
> You can't get lint attributes from other crates. I would probably just restrict the lint to only work with types from the current crate while you're at it. Upstream crates don't have a definition order from the point of view of the current crate (with the exception of #[repr(C)] structs).
changelog: Respect allow `inconsistent_struct_constructor` on the struct definition.
Add lint for `unused_result_ok`
This PR adds a lint to capture the use of `expr.ok();` when the result is not _really_ used.
This could be interpreted as the result being checked (like it is with `unwrap()` or `expect`) but
it actually only ignores the result.
`let _ = expr;` expresses that intent better.
This was also mentionned in #8994 (although not being the main topic of that issue).
changelog: [`misleading_use_of_ok`]: Add new lint to capture `.ok();` when the result is not _really_ used.
Remove `multispan_sugg[_with_applicability]`
They're thin wrappers over the corresponding diag method so we should just use that instead
changelog: none
Add test for `try_err` lint within try blocks.
Fixes#5757
Turns out the current `try_err` implementation already skips expressions inside of a try block.
When inside of a try block, `Err(_)?` is desugared to a `break` instead of normal `return` . This makes `find_return_type()` function at [this line](eb4d88e690/clippy_lints/src/matches/try_err.rs (L29)) always returns `None` and skips the check.
I just added a test case for try block.
changelog: none
Fix [`redundant_slicing`] when the slice is behind a mutable reference
Fixes#12751
changelog: Fix [`redundant_slicing`] when the slice is behind a mutable reference and a immutable reference is expected.
When a suggestion part is for already present code, do not highlight it. If after that there are no highlights left, do not show the suggestion at all.
Fix clippy lint suggestion incorrectly treated as `span_help`.
Fix `redundant_closure` false positive with closures has return type contains `'static`
Fix#13073 .
Please enable "ignore white-space change" settings in github UI for easy reviewing.
HACK: The third commit contains a hack to check if a type `T: 'static` when `fn() -> U where U: 'static`.
I don't have a clean way to check for it.
changelog: [`redundant_closure`] Fix false positive with closures has return type contains `'static`
Fix false positive for `missing_backticks` in footnote references
Fixes#13183.
changelog: Fix false positive for `missing_backticks` in footnote references
Emit `if_let_mutex` in presence of other mutexes
Currently (master, not nightly nor stable) `if_let_mutex` does not emit a warning here:
```rs
let m1 = Mutex::new(10);
let m2 = Mutex::new(());
if let 100..=200 = *m1.lock().unwrap() {
m2.lock();
} else {
m1.lock();
}
```
It currently looks for the first call to `.lock()` on *any* mutex receiver inside of the if/else body, and only later (outside of the visitor) checks that the receiver matches the mutex in the scrutinee. That means that in cases like the above, it finds the `m2.lock()` expression, stops the visitor, fails the check that it's the same mutex (`m2` != `m1`) and then does not look for any other `.lock()` calls.
So, just make the receiver check also part of the visitor so that we only stop the visitor when we also find the right receiver.
The first commit has the actual changes described here. The sceond one just unnests all the `if let`s
----
changelog: none
`missing_trait_methods`: lint methods in definition order
Lintcheck for #13157 showed a bunch of changes for `missing_trait_methods`
This is because `values_sorted` was sorting the entries by the key's [`DefPathHash`](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_span/def_id/struct.DefPathHash.html), this is stable for a given compiler but can change across versions
changelog: none
Fix while_let_on_iterator dropping loop label when applying fix.
Loop label was not persisted when displaying help and was therefore producing broken rust code when applying fixes.
Solution was to store the `ast::Label` when creating a `higher::WhileLet` from an expression and add the label name to the lint suggestion and diagnostics.
---
Fixes: https://github.com/rust-lang/rust-clippy/issues/13123
changelog: [`while_let_on_iterator`]: Fix issue dropping loop label when displaying help and applying fixes.
Add `BTreeSet` detection to the `set_contains_or_insert` lint
* Detect `BTreeSet::contains` + `BTreeSet::insert` usage in the same way as with the `HashSet`.
CC: `@lochetti` `@bitfield`
----
changelog: [`set_contains_or_insert`]: Handle `BTreeSet` in addition to `HashSet`
Make `std_instead_of_core` somewhat MSRV aware
For #13158, this catches some things e.g. `core::net` and the recently stable `core::error` but not things moved individually like `UnwindSafe`, as far as I can see the version for those isn't easily available
Beta nominating since ideally we'd get this change in the same version as `core::error` becomes stable
cc `@kpreid`
changelog: none
Stabilize const `{integer}::from_str_radix` i.e. `const_int_from_str`
This PR stabilizes the feature `const_int_from_str`.
- ACP Issue: rust-lang/libs-team#74
- Implementation PR: rust-lang/rust#99322
- Part of Tracking Issue: rust-lang/rust#59133
API Change Diff:
```diff
impl {integer} {
- pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
+ pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError>;
}
impl ParseIntError {
- pub fn kind(&self) -> &IntErrorKind;
+ pub const fn kind(&self) -> &IntErrorKind;
}
```
This makes it easier to parse integers at compile-time, e.g.
the example from the Tracking Issue:
```rust
env!("SOMETHING").parse::<usize>().unwrap()
```
could now be achived with
```rust
match usize::from_str_radix(env!("SOMETHING"), 10) {
Ok(val) => val,
Err(err) => panic!("Invalid value for SOMETHING environment variable."),
}
```
rather than having to depend on a library that implements or manually implement the parsing at compile-time.
---
Checklist based on [Libs Stabilization Guide - When there's const involved](https://std-dev-guide.rust-lang.org/development/stabilization.html#when-theres-const-involved)
I am treating this as a [partial stabilization](https://std-dev-guide.rust-lang.org/development/stabilization.html#partial-stabilizations) as it shares a tracking issue (and is rather small), so directly opening the partial stabilization PR for the subset (feature `const_int_from_str`) being stabilized.
- [x] ping Constant Evaluation WG
- [x] no unsafe involved
- [x] no `#[allow_internal_unstable]`
- [ ] usage of `intrinsic::const_eval_select` rust-lang/rust#124625 in `from_str_radix_assert` to change the error message between compile-time and run-time
- [ ] [rust-labg/libs-api FCP](https://github.com/rust-lang/rust/pull/124941#issuecomment-2207021921)
needless_borrows_for_generic_args: Fix for &mut
This commit fixes a bug introduced in #12706, where the behavior of the lint has been changed, to avoid suggestions that introduce a move. The motivation in the commit message is quite poor (if the detection for significant drops is not sufficient because it's not transitive, the proper fix would be to make it transitive). However, #12454, the linked issue, provides a good reason for the change — if the value being borrowed is bound to a variable, then moving it will only introduce friction into future refactorings.
Thus #12706 changes the logic so that the lint triggers if the value being borrowed is Copy, or is the result of a function call, simplifying the logic to the point where analysing "is this the only use of this value" isn't necessary.
However, said PR also introduces an undocumented carveout, where referents that themselves are mutable references are treated as Copy, to catch some cases that we do want to lint against. However, that is not sound — it's possible to consume a mutable reference by moving it.
To avoid emitting false suggestions, this PR reintroduces the referent_used_exactly_once logic and runs that check for referents that are themselves mutable references.
Thinking about the code shape of &mut x, where x: &mut T, raises the point that while removing the &mut outright won't work, the extra indirection is still undesirable, and perhaps instead we should suggest reborrowing: &mut *x. That, however, is left as possible future work.
Fixes#12856
changelog: none
Implement lint against ambiguous negative literals
This PR implements a lint against ambiguous negative literals with a literal and method calls right after it.
## `ambiguous_negative_literals`
(deny-by-default)
The `ambiguous_negative_literals` lint checks for cases that are confusing between a negative literal and a negation that's not part of the literal.
### Example
```rust,compile_fail
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```
### Explanation
Method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.
<details>
<summary>Old proposed lint</summary>
## `ambiguous_unary_precedence`
(deny-by-default)
The `ambiguous_unary_precedence` lint checks for use the negative unary operator with a literal and method calls.
### Example
```rust
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```
### Explanation
Unary operations take precedence on binary operations and method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.
</details>
-----
Note: This is a strip down version of https://github.com/rust-lang/rust/pull/117161, without the binary op precedence.
Fixes https://github.com/rust-lang/rust/issues/117155
`@rustbot` labels +I-lang-nominated
cc `@scottmcm`
r? compiler
Fix running compile-test under cargo nextest
`ui_test` itself has `cargo nextest` support which we now use - https://github.com/oli-obk/ui_test/pull/161
It prints `ui_test` as its test name whereas we printed `compile_test`, this ended up being treated as a test name filter causing all the tests to be filtered out
changelog: none
Misc refactorings part 5
`toplevel_ref_arg` gets a small fix so it can be allowed on function arguments. Otherwise just some rearrangements.
changelog: none
