We introduce the following rules for match exprs.
- `panic!` and `unreachable!` are treated as consumption.
- guard expressions in any arm imply consumption.
For match exprs:
- Lint only if exacrtly 2 non-consuming arms exist
- Lint only if one arm is an `Ok(_)` and the other is `Err(_)`
Added additional requirement that for a block return expression
that is a match, the source must be `Normal`.
changelog: FP [`unused_io_amount`] when matching Ok(literal)
`unused_io_amount` captures `Ok(_)`s
Partial rewrite of `unused_io_amount` to lint over `Ok(_)` and `Ok(..)`.
Moved the check to `check_block` to simplify context checking for expressions and allow us to check only some expressions.
For match (expr, arms) we emit a lint for io ops used on `expr` when an arm is `Ok(_)|Ok(..)`. Also considers the cases when there are guards in the arms and `if let Ok(_) = ...` cases.
For `Ok(_)` and `Ok(..)` it emits a note indicating where the value is ignored.
changelog: False Negatives [`unused_io_amount`]: Extended `unused_io_amount` to catch `Ok(_)`s in `If let` and match exprs.
Closes#11713
r? `@giraffate`
Partial rewrite of `unused_io_account` to lint over Ok(_).
Moved the check to `check_block` to simplify context checking for
expressions and allow us to check only some expressions.
For match (expr, arms) we emit a lint for io ops used on `expr` when an
arm is `Ok(_)`. Also considers the cases when there are guards in the
arms. It also captures `if let Ok(_) = ...` cases.
For `Ok(_)` it emits a note indicating where the value is ignored.
changelog: False Negatives [`unused_io_amount`]: Extended
`unused_io_amount` to catch `Ok(_)`s in `If let` and match exprs.
no_effect_underscore_binding: _ prefixed variables can be used
Prefixing a variable with a `_` does not mean that it will not be used. If such a variable is used later, do not warn about the fact that its initialization does not have a side effect as this is fine.
changelog: [`no_effect_underscore_binding`]: warn only if variable is unused
Fix#12166
Add . to end of lint lists in configuration + Fix typo in pub_underscore_fields_behavior
Fixes https://github.com/rust-lang/rust-clippy/pull/10283#issuecomment-1890600381
In the "/// Lint: " list on each configuration option, you have to end with a dot. If the lint list doesn't have a dot, the configuration won't have documentation.
This PR adds those missing dots in some of the configuration, thus also adding their documentation.
changelog: Fix bug where a lot of config documentation wasn't showing.
changelog: Fix typo in `pub_underscore_fields_behavior` (`PublicallyExported` -> `PubliclyExported`)
Find function path references early in the same lint pass
This removes a visitor that existed to collect paths to functions in a context where the exact signature is required in order to cancel the lint.
E.g. when there's a `let _: fn(&mut i32) = path_to_fn_ref_mut_i32;` statement somewhere in the crate, we shouldn't suggest removing the mutable reference in the function signature.
It was doing a whole pass through the crate at the end, which seems unnecessary.
It seems like we should be able to add entries to the map in the same lint pass.
The map is untouched all the way until `check_crate_post` (at which point it will be populated by the visitor and finally checked), so it doesn't seem like this changes behavior: it will only be fully populated by the time we reach `check_crate_post` no matter what.
I don't think this will have a significant perf impact but it did show up in a profile with 0.5% for a crate I was looking into and looked like a low hanging fruit.
changelog: none
Prefixing a variable with a `_` does not mean that it will not be used.
If such a variable is used later, do not warn about the fact that its
initialization does not have a side effect as this is fine.
Fix error warning span for issue12045
fixes [Issue#12045](https://github.com/rust-lang/rust-clippy/issues/12045)
In issue#12045, unexpected warning span occurs on attribute `#[derive(typed_builder::TypedBuilder)]`, actually the warning should underline `_lifetime`.
In the source code we can find that the original intend is to warning on `ident.span`, but in this case, `stmt.span` is unequal with `ident.span`. So, fix the nit here is fine.
Besides, `ident.span` have an accurate range than `stmt.span`.
changelog: [`no_effect_underscore_binding`]: correct warning span
blocks_in_conditions: do not warn if condition comes from macro
changelog: [`blocks_in_conditions`]: do not warn if condition comes from macro
Fix#12162
fix FP on [`semicolon_if_nothing_returned`]
fixes: #12123
---
changelog: fix FP on [`semicolon_if_nothing_returned`] which suggesting adding semicolon after attr macro
[`default_numeric_fallback`]: improve const context detection
Fixes#12159
The lint didn't actually recognize any of the associated consts (in the linked issue), because in those cases the parent is an `ImplItem` and not an `Item`, but it only actually emitted a lint for i32 and f64 because the other cases failed the very last check here
bb2d497364/clippy_lints/src/default_numeric_fallback.rs (L91-L96)
A better check for detecting constness would be using `body_const_context`, which is what this PR does.
changelog: [`default_numeric_fallback`]: recognize associated consts
Fix [`multiple_crate_versions`] to correctly normalize package names to avoid missing the local one
Fixes#12145
changelog: [`multiple_crate_versions`]: correctly normalize package name
Correctly handle type relative in trait_duplication_in_bounds lint
Fixes#9961.
The generic bounds were not correctly checked and left out `QPath::TypeRelative`, making different bounds look the same and generating invalid errors (and fix).
r? `@blyxyas`
changelog: [`trait_duplication_in_bounds`]: Correctly handle type relative.
`read_zero_byte_vec` refactor for better heuristics
Fixes#9274
Previously, the implementation of `read_zero_byte_vec` only checks for the next statement after the vec init. This fails when there is a block with statements that are expanded and walked by the old visitor.
This PR refactors so that:
1. It checks if there is a `resize` on the vec
2. It works on blocks properly
e.g. This should properly lint now:
```
let mut v = Vec::new();
{
f.read(&mut v)?;
//~^ ERROR: reading zero byte data to `Vec`
}
```
changelog: [`read_zero_byte_vec`] Refactored for better heuristics
Add suspicious_open_options lint.
changelog: [`suspicious_open_options`]: Checks for the suspicious use of std::fs::OpenOptions::create() without an explicit OpenOptions::truncate().
create() alone will either create a new file or open an existing file. If the file already exists, it will be overwritten when written to, but the file will not be truncated by default. If less data is written to the file than it already contains, the remainder of the file will remain unchanged, and the end of the file will contain old data.
In most cases, one should either use `create_new` to ensure the file is created from scratch, or ensure `truncate` is called so that the truncation behaviour is explicit. `truncate(true)` will ensure the file is entirely overwritten with new data, whereas `truncate(false)` will explicitely keep the default behavior.
```rust
use std::fs::OpenOptions;
OpenOptions::new().create(true).truncate(true);
```
- [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`
Try to improve wording and fix dead link in description of arc_with_non_send_sync lint.
changelog: [`arc_with_non_send_sync`]: Improve wording and fix dead link.
Correctly suggest std or core path depending if this is a `no_std` crate
A few lints emit suggestions using `std` paths whether or not this is a `no_std` crate, which is an issue when running `rustfix` afterwards. So in case this is an item that is defined in both `std` and `core`, we need to check if the crate is `no_std` to emit the right path.
r? `@llogiq`
changelog: Correctly suggest std or core path depending if this is a `no_std` crate
Add "OpenTelemetry" to default `doc_valid_idents`
The OpenTelemetry project's name is all one word (see https://opentelemetry.io), so currently triggers a false positive in the `doc_markdown` lint.
The project is increasing rapidly in popularity, so it seems like a worthy contender for inclusion in the default `doc_valid_idents` configuration.
I've also moved the existing "OpenDNS" entry earlier in the list, to restore the alphabetical ordering of that "Open*" row.
The docs changes were generated using `cargo collect-metadata`.
changelog: [`doc_markdown`]: Add `OpenTelemetry` to the default configuration as an allowed identifier
- New ineffective_open_options had to be fixed.
- Now not raising an issue on missing `truncate` when `append(true)`
makes the intent clear.
- Try implementing more advanced tests for non-chained operations. Fail
Checks for the suspicious use of OpenOptions::create()
without an explicit OpenOptions::truncate().
create() alone will either create a new file or open an
existing file. If the file already exists, it will be
overwritten when written to, but the file will not be
truncated by default. If less data is written to the file
than it already contains, the remainder of the file will
remain unchanged, and the end of the file will contain old
data.
In most cases, one should either use `create_new` to ensure
the file is created from scratch, or ensure `truncate` is
called so that the truncation behaviour is explicit.
`truncate(true)` will ensure the file is entirely overwritten
with new data, whereas `truncate(false)` will explicitely
keep the default behavior.
```rust
use std::fs::OpenOptions;
OpenOptions::new().create(true).truncate(true);
```
The OpenTelemetry project's name is all one word (see https://opentelemetry.io),
so currently triggers a false positive in the `doc_markdown` lint.
The project is increasing rapidly in popularity, so it seems like a worthy
contender for inclusion in the default `doc_valid_idents` configuration.
I've also moved the existing "OpenDNS" entry earlier in the list, to restore
the alphabetical ordering of that "Open*" row.
The docs changes were generated using `cargo collect-metadata`.
changelog: [`doc_markdown`]: Add `OpenTelemetry` to the default configuration as an allowed identifier
[`useless_asref`]: check that the clone receiver is the parameter
Fixes#12135
There was no check for the receiver of the `clone` call in the map closure. This makes sure that it's a path to the parameter.
changelog: [`useless_asref`]: check that the clone receiver is the closure parameter
['arc_with_non_send_sync`] documentation edits
Arc's documentation uses the term "thread"; aligning to that terminology. Fix casing of "Rc".
changelog: None
Make `HirEqInterExpr::eq_block` take comments into account while checking if two blocks are equal
This PR:
- now makes `HirEqInterExpr::eq_block` take comments into account. Identical code with varying comments will no longer be considered equal.
- makes necessary adjustments to UI tests.
Closes#12044
**Lintcheck Changes**
- `match_same_arms` 53 => 52
- `if_same_then_else` 3 => 0
changelog: [`if_same_then_else`]: Blocks with different comments will no longer trigger this lint.
changelog: [`match_same_arms`]: Arms with different comments will no longer trigger this lint.
```
