[`drop_ref`]: don't lint idiomatic in match arm
fixes#10122
As established in issue #9482, it is idiomatic to use a single `drop()` expression in a match arm to achieve a side-effect of a function while discarding its output. This should also apply to cases where the function returns a reference.
The change to the lint's code was less than 1 line, because all the heavy lifting was done in PR #9491.
---
changelog: FP: [`drop_ref`]: No longer lints idiomatic expression in `match` arms
[#10142](https://github.com/rust-lang/rust-clippy/pull/10142)
<!-- changelog_checked -->
Expand derivable-impls to cover enums with a default unit variant.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`derivable_impls`]: suggest deriving Default for enums with a default unit variant
Make the iter_kv_map lint handle ref/mut annotations.
For the degenerate (`map(|(k, _)| k)`/`map(|(_, v)| v)`) cases a mut annotation is superfluous and a ref annotation won't compile, so no additional handling is required. For cases where the `map` call must be preserved ref/mut annotations should also be presereved so that the map body continues to work as expected.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`iter_kv_map`]: handle ref/mut annotations
For the degenerate (`map(|(k, _)| k)`/`map(|(_, v)| v)`) cases a mut annotation is superfluous and a ref annotation won't compile, so no additional handling is required. For cases where the `map` call must be preserved ref/mut annotations should also be presereved so that the map body continues to work as expected.
chore: add simple comment for `get_enclosing_block`
I was reading the code of `clippy_utils/src/lib.rs` and thought that adding comment on `get_closing_block` would be helpful to first time visitor.
---
changelog: none
<!-- changelog_checked -->
don't lint field_reassign when field in closure
fixes#10136
This change makes the ContainsName struct visit all interior expressions, which means that ContainsName will return true even if `name` is used in a closure within `expr`.
---
changelog: FP: [`field_reassign_with_default`]: No longer lints cases, where values are initializes from closures capturing struct values
[#10143](https://github.com/rust-lang/rust-clippy/pull/10143)
<!-- changelog_checked -->
chore: fix identation of `if_chain` in `filter_map`
This is a really small fix.
If someone could take a look at it, I would appreciate it🙏
---
changelog: none
<!-- changelog_checked -->
This commit makes the ContainsName struct visit all interior
expressions, which means that ContainsName will return true
even if `name` is used in a closure within `expr`.
Move `mutex_atomic` to `restriction`
By #4295, the general consensus seems to be that `mutex_atomic` is not a useful lint in most cases. If anything, it could be useful as a restriction on code that for whatever reason can't use atomics. Keeping it in `clippy::nursery` is harmful to people attempting to use clippy for soundness.
---
changelog: Moved [`mutex_atomic`] to `restriction`
[#10115](https://github.com/rust-lang/rust-clippy/pull/10115)
<!-- chnagelog_checked -->
fix incorrect suggestion in `suboptimal_flops`
fixes#10003
There was an error when trying to negate an expression like `x - 1.0`. We used to format it as `-x - 1.0` whereas a proper negation would be `-(x - 1.0)`.
Therefore, we add parentheses around the expression when it is `ExprKind::Binary`.
We also add parentheses around multiply and divide expressions, even though this is not strictly necessary.
changelog: [`suboptimal_flops`]: fix incorrect suggestion caused by an incorrect negation of floating point expressions.
There was an error when trying to negate an expression
like `x - 1.0`. We used to format it as `-x - 1.0` whereas
a proper negation would be `-(x - 1.0)`.
Therefore, we add parentheses around the expression when it is a
Binary ExprKind.
We also add parentheses around multiply and divide expressions,
even though this is not strictly necessary.
This patch not only improves visibility, but also fixes a potential bug.
When a lint description ends with code block, the string will have three
backquotes at the end.
Since the current implementation prints the default value immediately
after that, the markdown renderer is unable to properly close the code
block.
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 -->
