Current implementation looks for significant drops, that can change the
behavior, but that's not enough - value might not have a Drop itself but
one of its children might have it.
A good example is passing a reference to `PathBuf` to `std::fs::File::open`.
There's no benefits to pass `PathBuf` by value, but since clippy can't
see `Drop` on `Vec` several layers down it complains forcing pass by
value and making it impossible to use the same name later.
New implementation only looks at copy values or values created inplace
so existing variable will never be moved but things that take a string
reference created and value is created inplace `&"".to_owned()` will
make it to suggest to use `"".to_owned()` still.
Fixes https://github.com/rust-lang/rust-clippy/issues/12454
Suggest collapsing nested or patterns if the MSRV allows it
Nested `or` patterns have been stable since 1.53, so we should be able to suggest `Some(1 | 2)` if the MSRV isn't set below that.
This change adds an msrv check and also moves it to `matches/mod.rs`, because it's also needed by `redundant_guards`.
changelog: [`collapsible_match`]: suggest collapsing nested or patterns if the MSRV allows it
fix suggestion error for [`manual_is_ascii_check`] with missing type
fixes: #11324fixes: #11776
changelog: improve [`manual_is_ascii_check`] to suggest labeling type in closure, fix FP with type generics, and improve linting on ref expressions.
suppress `readonly_write_lock` for underscore-prefixed bindings
Fixes#12733
Unsure if there's a better way to prevent this kind of false positive but this is the one that made most sense to me.
In my experience, prefixing bindings with an underscore is the usual way to name variables that aren't used and that exist purely for executing drop code at the end of the scope.
-------
changelog: suppress [`readonly_write_lock`] for underscore-prefixed bindings
check if closure as method arg has read access in [`collection_is_never_read`]
fixes: #11783
---
changelog: fix [`collection_is_never_read`] misfires when use `retain` for iteration
configurably allow `useless_vec` in tests
This adds a `àllow-useless-vec-in-test` configuration which, when set to `true` will allow the `useless_vec` lint in `#[test]` functions and code within `#[cfg(test)]`. It also moves a `is_in_test` helper to `clippy_utils`.
---
changelog: configurably allow [`useless_vec`] in test code
This adds a `àllow-useless-vec-in-test` configuration which, when set
to `true` will allow the `useless_vec` lint in `#[test]` functions and
code within `#[cfg(test)]`. It also moves a `is_in_test` helper to
`clippy_utils`.
fix [`large_stack_arrays`] linting in `vec` macro
fixes: #12586
this PR also adds a wrapper function `matching_root_macro_call` to `clippy_utils::macros`, considering how often that same pattern appears in the codebase.
(I'm always very indecisive towards naming, so, if anyone have better idea of how that function should be named, feel free to suggest it)
---
changelog: fix [`large_stack_arrays`] linting in `vec` macro; add `matching_root_macro_call` to clippy_utils
[`non_canonical_partial_ord_impl`]: Fix emitting warnings which conflict with `needless_return`
fixes#12683
---
changelog: fix [`non_canonical_partial_ord_impl`] emitting warnings which conflict with `needless_return`
Disallow ambiguous attributes on expressions
This implements the suggestion in [#15701](https://github.com/rust-lang/rust/issues/15701#issuecomment-2033124217) to disallow ambiguous outer attributes on expressions. This should resolve one of the concerns blocking the stabilization of `stmt_expr_attributes`.
reduce `single_char_pattern` to only lint on ascii chars
This should mostly fix the `single_char_pattern` lint, because with a single byte, the optimizer will usually see through the char-to-string-expansion and single loop iteration. This fixes#11675 and #8111.
Update: As per the meeting on November 28th, 2023, we voted to also downgrade the lint to pedantic.
---
changelog: downgrade [`single_char_pattern`] to `pedantic`
Fix `is_test_module_or_function`
The rustdoc comment for `is_test_module_or_function` states: 2795a60189/clippy_utils/src/lib.rs (L2561-L2566)
Given `item`, the function calls `is_in_test_function` with `item.hir_id()`. However, `is_in_test_function` considers only `item`'s parents, not `item` itself. This PR fixes the problem.
The `test_with_disallowed_name` test fails without the fix, but passes once applied.
changelog: none
Rework interior mutability detection
Replaces the existing interior mutability detection, the two main changes being
- It now follows references/pointers e.g. `struct S(&Cell)`
- `mutable_key_type` ignores pointers as it did before
- The `ignore_interior_mutability` config now applies to types containing the ignored type, e.g. `http::HeaderName`
Fixes https://github.com/rust-lang/rust-clippy/issues/7752
Fixes https://github.com/rust-lang/rust-clippy/issues/9776
Fixes https://github.com/rust-lang/rust-clippy/issues/9801
changelog: [`mutable_key_type`], [`declare_interior_mutable_const`]: now considers types that have references to interior mutable types as interior mutable
This commit introduces a check to ensure that the lint won't trigger when the initializer is
unreachable, such as:
```
thread_local! {
static STATE: Cell<usize> = panic!();
}
```
This is achieved by looking at the unpeeled initializer expression and ensuring that the parent
macro is not `panic!()`, `todo!()`, `unreachable!()`, `unimplemented!()`.
fixes#12637
changelog: [`threadlocal_initializer_can_be_made_const`] will no longer trigger on `unreachable` macros.
Emit the `needless_pass_by_ref_mut` lint on `self` arguments as well
Fixes https://github.com/rust-lang/rust-clippy/issues/12589.
Fixes https://github.com/rust-lang/rust-clippy/issues/9591.
The first commit fixes a bug I uncovered while working on this: sometimes, the mutable borrow "event" happens before the alias one, which makes some argument detected as not used mutably even if they are. The fix was simply to fill the map with the aliases afterwards.
The second commit removes the restriction to not run `self` argument for the `needless_pass_by_ref_mut` lint.
changelog: emit the `needless_pass_by_ref_mut` lint on `self` arguments as well
r? `@Manishearth`
fix: incorrect suggestions when `.then` and `.then_some` is used
fixes#11910
In the current implementation of `search_is_some`, if a `.is_none` call is followed by a `.then` or `.then_some` call, the generated `!` will incorrectly negate the values returned by the `then` and `.then_some` calls. To fix this, we need to add parentheses to the generated suggestions when appropriate.
changelog: [`search_is_some`]: add parenthesis to suggestions when appropriate
[`module_name_repetition`] Recognize common prepositions
Fixes#12544
changelog: [`module_name_repetition`]: don't report an item name if it consists only of a prefix from `allowed-prefixes` list and a module name (e.g. `AsFoo` in module `foo`). Prefixes allowed by default: [`to`, `from`, `into`, `as`, `try_into`, `try_from`]
Use `check_attributes` in doc lints
Ensures we catch all the places that doc comments could occur, found one that we were currently missing - docs on `extern` items
changelog: none
Fixes#12544.
- don't report an item name if it consists only of a prefix from `allowed-prefixes` list and a module name (e.g. `AsFoo` in module `foo`).
- configured by `allowed-prefixes` config entry
- prefixes allowed by default: [`to`, `from`, `into`, `as`, `try_into`, `try_from`]
- update docs
Correct parentheses for [`needless_borrow`] suggestion
This fixes#12268
Clippy no longer adds unnecessary parentheses in suggestions when the expression is part of a tuple.
---
changelog: Fix [`needless_borrow`] unnecessary parentheses in suggestion.
Add consistency with phrases "meantime" and "mean time"
"mean time" is used in a few places while "meantime" is used everywhere else; this would make usage consistent throughout the codebase.
fix incorrect suggestion for `!(a as type >= b)`
fixes#12625
The expression `!(a as type >= b)` got simplified to `a as type < b`, but because of rust's parsing rules that `<` is interpreted as a start of generic arguments for `type`. This is fixed by recognizing this case and adding extra parens around the left-hand side of the comparison.
changelog: [`nonminimal_bool`]: fix incorrect suggestion for `!(a as type >= b)`
[`manual_unwrap_or_default`]: Check for Default trait implementation in initial condition when linting and use `IfLetOrMatch`
Fixes#12564
changelog: Fix [`manual_unwrap_or_default`] false positive when initial `match`/`if let` condition doesn't implement `Default` but the return type does.
Allow `cast` lints in macros
closes: #11738
Removed the `from_expansion` guard clause for cast lints, so that these warnings can be generated for internal macros.
changelog: allow `cast` lints in macros
type certainty: clear `DefId` when an expression's type changes to non-adt
Fixes#12585
The root cause of the ICE in the linked issue was in the expression `one.x`, in the array literal.
The type of `one` is the `One` struct: an adt with a DefId, so its certainty is `Certain(def_id_of_one)`. However, the field access `.x` can then change the type (to `i32` here) and that should update that `DefId` accordingly. It does do that correctly when `one.x` would be another adt with a DefId:
97ba291d5a/clippy_utils/src/ty/type_certainty/mod.rs (L90-L91)
but when it *isn't* an adt and there is no def id (which is the case in the linked issue: `one.x` is an i32), it keeps the `DefId` of `One`, even though that's the wrong type (which would then lead to a contradiction later when joining `Certainty`s):
97ba291d5a/clippy_utils/src/ty/type_certainty/mod.rs (L92-L93)
In particular, in the linked issue, `from_array([one.x, two.x])` would try to join the `Certainty` of the two array elements, which *should* have been `[Certain(None), Certain(None)]`, because `i32`s have no `DefId`, but instead it was `[Certain(One), Certain(Two)]`, because the DefId wasn't cleared from when it was visiting `one` and `two`. This is the "contradiction" that could be seen in the ICE message
... so this changes it to clear the `DefId` when it isn't an adt.
cc `@smoelius` you implemented this initially in #11135, does this change make sense to you?
changelog: none
Reword `arc_with_non_send_sync` note and help messages
Addresses https://github.com/rust-lang/rust-clippy/issues/12608#issuecomment-2029688054
Makes the note more concise and reframes the `Rc` suggestion around whether it crosses threads currently due to a manual `Send`/`Sync` impl or may do in the future
changelog: none
FIX(12334): manual_swap auto fix
Fixed: #12334
Initialization expressions are now generated as needed if the slice index is bound to a variable.
----
changelog: Fix [`manual_swap`]
Do not suggest `assigning_clones` in `Clone` impl
This PR modifies `assigning_clones` to detect situations where the `clone` call is inside a `Clone` impl, and avoids suggesting the lint in such situations.
r? `@blyxyas`
Fixes: https://github.com/rust-lang/rust-clippy/issues/12600
changelog: Do not invoke `assigning_clones` inside `Clone` impl
avoid an ICE in `ptr_as_ptr` when getting the def_id of a local
Fixes#12616
`Res::def_id` can panic, so avoid calling it in favor of `opt_def_id`, so we can gracefully handle resolutions that don't have a `DefId` (e.g. local variables) and get a false negative in the worst case, rather than an ICE
changelog: Fix ICE in [`ptr_as_ptr`] when the cast expression is a function call to a local variable
Initialization expressions are now generated when index is bound to a variable.
FIX: Check to see if variables are used after swap
FIX: rename StmtKind::Local to StmtKind::Let
Elide unit variables linted by `let_unit` and use `()` directly instead
Situation: `let_unit` lints when an expression binds a unit (`()`) to a variable. In some cases this binding may be passed down to another function. Currently, the lint removes the binding without considering usage.
fixes: #12594
changelog: Suggestion Fix [`let_unit`]. Clippy will remove unit bindings and replace all their instances in the body with `()`.
Situation: `let_unit` lints when an expression binds a unit (`()`)
to a variable. In some cases this binding may be passed down to
another function. Currently, the lint removes the binding without
considering usage.
Change: All usages of the elided variable are now replaced with `()`.
fixes: #12594
`Box::default()` had its `#[rustc_box]` attribute removed in 1.69 so is
no longer a perf related lint
The lint is moved to style but no longer produces suggestions containing
turbofishes, as they're often longer/more annoying to type
Allow `filter_map_identity` when the closure is typed
This extends the `filter_map_identity` lint to support typed closures.
For untyped closures, we know that the program compiles, and therefore we can safely suggest using flatten.
For typed closures, they may participate in type resolution. In this case we use `Applicability::MaybeIncorrect`.
Details:
https://rust-lang.zulipchat.com/#narrow/stream/257328-clippy/topic/Should.20.60filter_map_identity.60.20lint.20when.20closures.20are.20typed.3F
changelog: `filter_map_identity` will now suggest using flatten for typed closures.
r? `@y21` && `@Centri3`
[`type_id_on_box`]: lint on any `Box<dyn _>`
Closes#11349.
It now not only lints when calling `.type_id()` on the type `Box<dyn Any>`, but also on any `Box<dyn Trait>` where `Trait` is a subtrait of `Any`
changelog: FN: [`type_id_on_box`]: lint if `Any` is a sub trait
new lint `legacy_numeric_constants`
Rework of #10997
- uses diagnostic items
- does not lint imports of the float modules (`use std::f32`)
- does not lint usage of float constants that look like `f32::MIN`
I chose to make the float changes because the following pattern is actually pretty useful
```rust
use std::f32;
let omega = freq * 2 * f32::consts::PI;
```
and the float modules are not TBD-deprecated like the integer modules.
Closes#10995
---
changelog: New lint [`legacy_numeric_constants`]
[#12312](https://github.com/rust-lang/rust-clippy/pull/12312)
make sure checked type implements `Try` trait when linting [`question_mark`]
(indirectly) fixes: #12412 and fixes: #11983
---
changelog: make sure checked type implements `Try` trait when linting [`question_mark`]
restrict manual_clamp to const case, bring it out of nursery
Implements the plan that I described in https://github.com/rust-lang/rust-clippy/pull/9484#issuecomment-1374522054
This does two things primarily
1. Restrict `manual_clamp` such that it will only trigger if we are able to guarantee that `clamp` won't panic at runtime.
2. Bring `manual_clamp` out of nursery status and move it into the complexity group.
changelog: [`manual_clamp`]: Restrict this lint such that it only triggers if max and min are const, and max is greater than or equal to min. Then bring it out of the nursery group.
Instead of just saying “this function's stack frame is big”, report:
* the (presumed) size of the frame
* the size and type of the largest local contributing to that size
* the configurable limit that was exceeded (once)
`useless_asref`: do not lint `.as_ref().map(Arc::clone)`
This applies to `Arc`, `Rc`, and their weak variants. Using `.clone()` would be less idiomatic.
This follows the discussion in <https://github.com/rust-lang/rust-clippy/issues/12528#issuecomment-2014444305>.
changelog: [`useless_asref`]: do not lint `.as_ref().map(Arc::clone)` and similar
don't lint [`mixed_attributes_style`] when mixing docs and other attrs
fixes: #12435fixes: #12436fixes: #12530
---
changelog: don't lint [`mixed_attributes_style`] when mixing different kind of attrs; and move it to late pass;
don't lint [`mixed_attributes_style`] when mixing docs and other attrs
add test files for issue #12436
move [`mixed_attributes_style`] to `LateLintPass` to enable global `allow`
stop [`mixed_attributes_style`] from linting on different attributes
add `@compile-flags` to [`mixed_attributes_style`]'s test;
turns out not linting in test mod is not a FN.
Apply suggestions from code review
Co-authored-by: Timo <30553356+y21@users.noreply.github.com>
move [`mixed_attributes_style`] to late pass and stop it from linting on different kind of attributes
Note that the caller chooses a type for type param
```
error[E0308]: mismatched types
--> $DIR/return-impl-trait.rs:23:5
|
LL | fn other_bounds<T>() -> T
| - -
| | |
| | expected `T` because of return type
| | help: consider using an impl return type: `impl Trait`
| expected this type parameter
...
LL | ()
| ^^ expected type parameter `T`, found `()`
|
= note: expected type parameter `T`
found unit type `()`
= note: the caller chooses the type of T which can be different from ()
```
Tried to see if "expected this type parameter" can be replaced, but that goes all the way to `rustc_infer` so seems not worth the effort and can affect other diagnostics.
Revives #112088 and #104755.
Do not warn on .map(_::clone) for Arc, Rc, and their weak variants
Those constructions are idiomatic, and using `Arc::clone(x)` and `Rc::clone(x)` is often the recommended way of cloning a `Arc` or a `Rc`.
Fix#12528
changelog: [`map_clone`]: do not warn on `.map(_::clone)` for `Arc`, `Rc`, and their `Weak` variants
Fix infinite loop in `cast_sign_loss` when peeling unwrap method calls
Fixes#12506
The lint wants to peel method calls but didn't actually reassign the expression, leading to an infinite loop.
----
changelog: Fix infinite loop in [`cast_sign_loss`] when having two chained `.unwrap()` calls
Several (doc) comments were super outdated or didn't provide enough context.
Some doc comments shoved everything in a single paragraph without respecting
the fact that the first paragraph should be a single sentence because rustdoc
treats these as item descriptions / synopses on module pages.
Disable `cast_lossless` when casting to u128 from any (u)int type
Fixes https://github.com/rust-lang/rust-clippy/issues/12492
Disables `cast_lossless` when casting to u128 from any int or uint type. The lint states that when casting to any int type, there can potentially be lossy behaviour if the source type ever exceeds the size of the destination type in the future, which is impossible with a destination of u128.
It's possible this is a bit of a niche edge case which is better addressed by just disabling the lint in code, but I personally couldn't think of any good reason to still lint in this specific case - maybe except if the source is a bool, for readability reasons :).
changelog: FP: `cast_lossless`: disable lint when casting to u128 from any (u)int type
