This lint detects inefficient or useless `{std,core}::mem::swap()` calls
such as:
```rust
// Should be `a = temp();`
swap(&mut a, &mut temp());
// Should be `*b = temp();`
swap(b, &mut temp());
// Should be `temp1(); temp2();` if we want to keep the side effects
swap(&mut temp1(), &mut temp2());
```
It also takes care of using a form appropriate for a `()` context if
`swap()` is part of a larger expression (don't ask me why this wouldn't
happen, I have no idea), by suggesting `{ x = y; }` (statement in block)
or `{std,core}::mem::drop((temp1(), temp2())`.
changelog: [`swap_with_temporary`]: new lint
Close#1968
Limit the recursion depth, as each level of nesting adds another deeper
projection.
There might be a more complex way of handling the problem, but infinite
recursions are bad, and don't allow Clippy to terminate properly.
changelog: [`significant_drop_tightening`]: do not recurse forever when
checking for attribute on type or its constituent
Fixesrust-lang/rust-clippy#13544
@rustbot label +L-nursery
- Do not replace macro results in then/else branches
- Extract condition snippet from the right context
- Make suggestion `MaybeIncorrect` if it would lead to losing comments
changelog: [`bool_to_int_with_if`]: properly handle macros
Fixesrust-lang/rust-clippy#14628
Instead of looking for angle brackets in the source code, use the HIR
and Ty interfaces to either copy the original type, or complete it with
`_` placeholders if all type and const generic arguments are inferred.
Fixesrust-lang/rust-clippy#14581
changelog: [`from_iter_instead_of_collect`]: show correct type in
suggestion
- Do not replace macro results in then/else branches
- Extract condition snippet from the right context
- Make suggestion `MaybeIncorrect` if it would lead to losing comments
This PR has started as an effort to proceed from the feedback in
rust-lang/rust-clippy#12861.
- Checks test functions (functions marked with `#[test]` annotation) for
redundant "test_" prefix.
- Auto-fix is supported (and handles collisions gracefully, see below).
- If removing "test_" prefix from, say, `test_foo()` results in a name
collision (either because function `foo()` is already defined within the
current scope, or because the `foo()` call exists within function --
thus creating an unwanted recursion), lint suggests function rename,
warning the user that a simple trimming of `test_` prefix will result in
a name collision.
- If removing "test_" prefix results in invalid identifier (consider
`test_const`, `test_`, `test_42`), then again no auto-fix is suggested,
user is asked to rename function, with a note that a simple prefix
trimming will result in an invalid function name.
(`Applicability::HasPlaceholders` is used and user is suggested to: drop
`test_` prefix + add `_works` suffix, i.e. `test_foo` becomes
`foo_works` -- but again, user has to apply those changes manually).
- If trimmed version of the function name is a valid identifier, doesn't
result in name collision or unwanted recursion, then user is able to run
auto-fix.
fixesrust-lang/rust-clippy#8931
changelog: new lint: [`redundant_test_prefix`]
To avoid crashing Clippy, the `bug!()` is used only when debug
assertions are enabled. In regular usage, the result will be the same as
before, but without the extra line printed on the standard output which
has the potential for disrupting shell scripts.
changelog: none
The `ui_test` crate still uses 2021 as the default edition for running
rustc-like tests. This creates an unwelcome discrepancy between
`cargo dev lint` which uses Rust 2024 by default, and running UI tests
through `compile-test`.
There is a specific test that `unsafe fn` are not lint, and that
`unsafe` blocks are not lint either. Since in edition 2024 `unsafe`
blocks are required inside `unsafe fn` to do unsafe things, set up a
specific test for edition 2021.
In edition 2024, `unsafe` blocks must be used inside `unsafe fn` to do
unsafe things. The `misnamed_getters` would not lint if the getter
expression was embedded inside an `unsafe` block.
By default, edition 2024 will capture all types and lifetimes present in
the function signature when using RPIT, while edition 2021 will capture
only the lifetimes present in the RPIT itself. Adding explicit `use<>`
markers will disable the edition-specific automatic rules when they
differ.
`assert_eq!()` and `assert_ne!()` are not expanded the same way as
`assert!()` (they use a `match` instead of a `if`). This makes them
being recognized as well.
Fixrust-lang/rust-clippy#14255
changelog: [`missing_asserts_for_indexing`]: consider `assert_eq!()` as
well
To avoid crashing Clippy, the `bug!()` is used only when debug assertions are
enabled. In regular usage, the result will be the same as before, but without
the extra line printed on the standard output which has the potential for
disrupting shell scripts.
fixes#7749.
This issue proposes searching for `DerefMut` impls, which is not done
here: every lifetime parameter (aka `<'a>`) is the input types is
considered to be potentially mutable, and thus deactivates the lint.
changelog: [`mut_from_ref`]: Fixes false positive, where lifetimes
nested in the type (e.g. `Box<&'a mut T>`) were not considered.
Fix#14461:
- insert parentheses as required in suggestion
- check MSRV before suggesting fix in `const` context
- do not lint macro expansion result
Commits have been logically separated to facilitate review, and start
with a refactoring (and simplification) of the existing code.
changelog: [`manual_is_power_of_two`]: insert parentheses as required in
suggestion, check MSRV before suggesting fix in `const` context, do not
lint macro expansion results
`clippy::len_without_is_empty` can be allowed at the type declaration
site, and this will prevent the lint from triggering even though the
lint is shown on the `len()` method definition.
This allows the lint to be expected even though it is allowed at the
type declaration site.
changelog: [`len_without_is_empty`]: the lint can now be `#[expect]`ed
on the `len()` method even when it is `#[allow]`ed on the definining
type.
Fixesrust-lang/rust-clippy#14597
`clippy::len_without_is_empty` can be allowed at the type declaration
site, and this will prevent the lint from triggering even though the
lint is shown on the `len()` method definition.
This allows the lint to be expected even though it is allowed at the
type declaration site.
This lint does more harm than good: in its description, it proposes to
rewrite `match` on `Vec<_>` indexes or slices by a version which cannot
panic but masks the failure by choosing the default variant.
The `clippy::indexing_slicing` restriction lint covers those cases more
safely, by suggesting to use a non-panicking version to retrieve the
value from the container, without suggesting to fallback to the default
success variant in case of failure.
This PR is an (opposite) alternative to #14208 (which will add a
suggestion to the lint matching the lint description). Discussion on
both PRs can be found [on
Zulip](https://rust-lang.zulipchat.com/#narrow/channel/257328-clippy/topic/Suggestions.20that.20suppress.20panics).
changelog: [`match_on_vec_items`]: deprecate lint
changelog: [cognitive_complexity]: Changed Test for this issue from
making sure its not a false positive to making sure its not a false
negative which was the original issue at hand. The test as it was would
also not fail without the change introduced. This test will show if any
regression is made in further pushes.
adds tests to https://github.com/rust-lang/rust-clippy/issues/14422
It's either unneeded (`warn`/`deny`) or can be replaced by individual
lints (`allow`). Also removes some redundant `allow`s covered by the
default `-Aunused` that I saw along the way
changelog: none
`unsafe_fields` is an incomplete feature; comments have been put near
`#![expect(incomplete_features)]` to ensure that we revisit the
situation when the feature becomes complete.
changelog: [`expl_impl_clone_on_copy`]: do not lint in the presence of
`unsafe` fields
Fixes#14558
This prevents forgotten `dbg!()` calls from entering Clippy codebase by
mistake.
Suggested by @y21 when one of my PR forgot to remove one `dbg!()` call.
changelog: none
Blocks created by desugaring will not contain an explicit `return`. Do
not suggest to add it when the user has no control over the desugared
code.
Also, ensure that in a `xxx.await` expression, the suggested `return` is
emitted before the whole expression, not before the `await` keyword.
Fix#14411
changelog: [`implicit_return`]: fix proposed `return` position in the
presence of asynchronous code
