new lint: `explicit_into_iter_fn_arg`
Closes#10743.
This adds a lint that looks for `.into_iter()` calls in a call expression to a function that already expects an `IntoIterator`. In those cases, explicitly calling `.into_iter()` is unnecessary.
There were a few instances of this in clippy itself so I fixed those as well in this PR.
changelog: new lint [`explicit_into_iter_fn_arg`]
manual_let_else: support struct patterns
This adds upon the improvements of #10797 and:
* Only prints `()` around `Or` patterns at the top level (fixing a regression of #10797)
* Supports multi-binding patterns: `let (u, v) = if let (Some(u_i), Ok(v_i)) = ex { (u_i, v_i) } else ...`
* Traverses through tuple patterns: `let v = if let (Some(v), None) = ex { v } else ...`
* Supports struct patterns: `let v = if let S { v, w, } = ex { (v, w) } else ...`
```
changelog: [`manual_let_else`]: improve pattern printing to support struct patterns
```
fixes#10708fixes#10424
[`ptr_cast_constness`]: Only lint on casts which don't change type
fixes#10874
changelog: [`ptr_cast_constness`]: Only lint on casts which don't change type
Emit `unnecessary_cast` on raw pointers as well
Supersedes(?) #10782, since this and #10567 will cover the original issue.
Does not lint on type aliases or inferred types.
changelog: [`unnecessary_cast`]: Also emit on casts between raw pointers with the same type and constness
Clippy Book Chapter Updates Reborn: Refresh Lint Configuration's looks
This PR modernizes and clears up some confusion with the "Lint Configuration Options" chapter from the book.
### Changes
- **Remove 'Option - Default Value" table**
- Why was it even there?
- It shouldn't be the first thing an user sees when they enter the chapter. It's clunky, ugly and not useful. The default values for configs are stated in a per-config basis if needed.
- **Add a simple description of what the chapter contains, and the scheme of each configuration option**
- **Minor formatting, mainly adding code fragments to code text**
- It seemed weird and jarring not having back-ticks on text like "arithmetic_side_effects".
- Improves readability and separation between configs.
- **Separate a little bit the Affected Lints list + "Affected lists" message**
- Not having something indicating that the list is about the lints that use the configuration option is confusing.
- It isn't as important as the description and example. Therefore should be separated a little bit imo
---
This is an independent effort from #10597, but as it's still a Book Chapter Update, I thought it would be cool to include it here. I'm going to keep the reviewing process for this PR to rustbot's desires.
[Rendered](https://github.com/blyxyas/rust-clippy/blob/book-lint_config/book/src/lint_configuration.md)
[Current](https://github.com/rust-lang/rust-clippy/blob/master/book/src/lint_configuration.md)
changelog: Refresh styling from the "Lint Configuration Options" book chapter.
Update *Current stable* text in `CHANGELOG.md`
Roses are red,
violets are blue,
the new version was released,
and our changelog too
---
changelog: none
add checking for cfg(features = ...)
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`maybe_misused_cfg`]: check if `#[cfg(feature = "...")]` misused as `#[cfg(features = "...")]`
I've found that there is no indication when `#[cfg(features = "...")]` is used incorrectly, which can easily make mistakes hard to spot. When I searched for this code on github, I also found many misuse cases([link](https://github.com/search?q=%23%5Bcfg%28features+language%3ARust&type=code)).
PS: This clippy name is just a temporary name, it can be replaced with a better name.
Add spans to `clippy.toml` error messages
Adds spans to errors and warnings encountered when parsing `clippy.toml`.
changelog: Errors and warnings generated when parsing `clippy.toml` now point to the location in the TOML file the error/warning occurred.
Explain which paths clippy searches for configuration in docs
Fixes https://github.com/rust-lang/rust-clippy/issues/9921.
Adds information on where to place the configuration files, it may be a bit verbose. Also added a comment to the section of the code where the search happens, to hopefully prevent changing that without updating the docs.
changelog: Make documentation about where to place configuration files clearer.
