Create new lint `option_map_or_err_ok`
Fixes#10045.
For the following code:
```rust
let opt = Some(1);
opt.map_or(Err("error"), Ok);
```
It suggests to instead write:
```rust
let opt = Some(1);
opt.ok_or("error");
```
r? `@flip1995`
changelog: Create new lint `option_map_or_err_ok`
suggest alternatives to iterate an array of ranges
works towards #7125
changelog: [`single_element_loop`]: suggest better syntax when iterating over an array of a single range
`@thinkerdreamer` and myself worked on this issue during a workshop by `@llogiq` at the RustLab 2023 conference. It is our first contribution to clippy.
When iterating over an array of only one element, _which is a range_, our change suggests to replace the array with the contained range itself. Additionally, a hint is printed stating that the user probably intended to iterate over the range and not the array. If the single element in the array is not a range, the previous suggestion in the form of `let {pat_snip} = {prefix}{arg_snip};{block_str}`is used.
This change lints the array with the single range directly, so any prefixes or suffixes are covered as well.
[`deprecated_semver`]: Allow `#[deprecated(since = "TBD")]`
"TBD" is allowed by rustdoc, saying that it will be deprecated in a future version. rustc will also not actually warn on it.
I found this while checking the rust-lang/rust with clippy.
changelog: [`deprecated_semver`]: allow using `since = "TBD"`
[`missing_asserts_for_indexing`]: work with bodies instead of blocks separately
Fixes#11856
Before this change, this lint would check blocks independently of each other, which means that it misses `assert!()`s from parent blocks.
```rs
// check_block
assert!(x.len() > 1);
{
// check_block
// no assert here
let _ = x[0] + x[1];
}
```
This PR changes it to work with bodies rather than individual blocks. That means that a function will be checked in one go and we can remember if an `assert!` occurred anywhere.
Eventually it would be nice to have a more control flow-aware analysis, possibly by rewriting it as a MIR lint, but that's more complicated and I wanted this fixed first.
changelog: [`missing_asserts_for_indexing`]: accept `assert!`s from parent blocks
Fix iter_kv_map false positive into_keys and into_values suggestion
fixes: #11752
changelog: [`iter_kv_map`]: fix false positive: Don't suggest `into_keys()` and `into_values()` if the MSRV is to low
Add tests for issues #10285, #10286, #10289, #10287Fixes#10285.
Fixes#10286.
Fixes#10289.
Fixes#10287.
This PR simply adds tests for the listed issues as they're already implemented so we can close them.
r? `@blyxyas`
changelog:none
[`needless_return_with_question_mark`]: don't lint if never type is used for coercion
Fixes#11616
When we have something like
```rs
let _x: String = {
return Err(())?;
};
```
we shouldn't suggest removing the `return` because the `!`-ness of `return` is used to coerce the enclosing block to some other type. That will lead to a typeck error without a diverging expression like `return`.
changelog: [`needless_return_with_question_mark`]: don't lint if `return`s never typed-ness is used for coercion
Split `doc.rs` up into a subdirectory
So, first, sorry for the bad diff. 😅
In #11798, `@flip1995` suggested splitting `doc.rs` up, much like how we have the `methods/`, `matches/`, `types/` subdirectories.
I agree with this, the file is getting bigger as we add more and more doc lints that it makes sense to do this refactoring.
This is purely an internal change that moves things around a bit.
(**EDIT:** depending on the outcome of https://github.com/rust-lang/rust-clippy/pull/11801#issuecomment-1816715615 , this may change the lint group name from `doc_markdoc` to `doc`).
I tried to not change any of the actual logic of the lints and as such some things weren't as easy to move to a separate file. So we still have some `span_lint*` calls in the `doc/mod.rs` file, which I think is fine. This is also the case in `methods/mod.rs`.
Also worth mentioning that the lints missing_errors_doc, missing_panics_doc, missing_safety_doc and unnecessary_safety_doc have a lot of the same logic so it didn't make much sense for each of these to be in their own file. Instead I just put them all in `missing_headers.rs`
I also added a bit of documentation to the involved `check_{attrs,doc}` methods.
changelog: none
Improve maybe misused cfg
Follow-up of the improvements that were suggested to me in https://github.com/rust-lang/rust-clippy/pull/11821:
* I unified the output to use the same terms.
* I updated the code to prevent creating a new symbol.
r? `@blyxyas`
changelog: [`maybe_misued_cfg`]: Output and code improvements
Verify Borrow<T> semantics for types that implement Hash, Borrow<str> and Borrow<[u8]>.
Fixes#11710
The essence of the issue is that types that implement Borrow<T> provide a facet or a representation of the underlying type. Under these semantics `hash(a) == hash(a.borrow())`.
This is a problem when a type implements `Borrow<str>`, `Borrow<[u8]>` and Hash, it is expected that the hash of all three types is identical. The problem is that the hash of [u8] is not the same as that of a String, even when the byte reference ([u8]) is derived from `.as_bytes()`
- [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`
---
- [x] Explanation of the issue in the code
- [x] Tests reproducing the issue
- [x] Lint rule and emission
---
changelog: New lint: [`impl_hash_borrow_with_str_and_bytes`]
[#11781](https://github.com/rust-lang/rust-clippy/pull/11781)
Implements a lint to prevent implementation of Hash, Borrow<str> and
Borrow<[u8]> as it breaks Borrow<T> "semantics". According to the book,
types that implement Borrow<A> and Borrow<B> must ensure equality of
borrow results under Eq,Ord and Hash.
> In particular Eq, Ord and Hash must be equivalent for borrowed and
owned values: x.borrow() == y.borrow() should give the same result as x == y.
In the same way, hash(x) == hash(x as Borrow<[u8]>) != hash(x as Borrow<str>).
changelog: newlint [`impl_hash_with_borrow_str_and_bytes`]
teach `eager_or_lazy` about panicky arithmetic operations
Fixes#9422Fixes#9814Fixes#11793
It's a bit sad that we have to do this because arithmetic operations seemed to me like the prime example where a closure would not be necessary, but this has "side effects" (changes behavior when going from lazy to eager) as some of these panic on overflow/underflow if compiled with `-Coverflow-checks` (which is the default in debug mode).
Given the number of backlinks in the mentioned issues, this seems to be a FP that is worth fixing, probably.
changelog: [`unnecessary_lazy_evaluations`]: don't lint if closure has panicky arithmetic operations
Extend `maybe_misused_cfg` lint over `cfg(test)`
Fixes#11240.
One thought I had is that we could use the levenshtein distance (of 1) to ensure this is indeed `test` that was targeted. But maybe it's overkill, not sure.
changelog: [`maybe_misused_cfg`]: Extend lint over `cfg(test)`
r? `@blyxyas`
Change `if_same_then_else` to be a `style` lint
CC #3770
From https://github.com/rust-lang/rust-clippy/issues/3770#issuecomment-687565594 (`@flip1995):`
> Oh I thought I replied to this: I definitely see now that having this
> as a correctness lint might be the wrong categorization. What we might
> want to do is to just allow this lint, if there are comments in the
> arm bodies. But a good first step would be to downgrade this lint to
> style or complexity. I would vote for style since merging two arms is
> not always less complex.
changelog: [`if_same_then_else`]: Change to be a `style` lint
disallow calls to `LintContext::struct_span_lint` and `TyCtxt::struct_span_lint_hir`
`LintContext::struct_span_lint` and `TyCtxt::struct_span_lint_hir` don't show the link to the clippy documentation, see: #11805
In #11810, the last few calls to those methods were replaced with `span_lint_*`. It seems like we should just disallow them altogether so that no new code tries to use them.
The existing `disallowed_methods` lint makes this easy.
changelog: none
[`impl_trait_in_params`]: avoid ICE when function with `impl Trait` type has no parameters
Fixes#11803
If I'm reading the old code correctly, it was taking the span of the first parameter (without checking that it exists, which caused the ICE) and uses that to figure out where the generic parameter to insert should go (cc `@blyxyas` you wrote the lint, is that correct?).
This seemed equivalent to just `generics.span`, which doesn't require calculating the spans like that and simplifies it a fair bit
changelog: don't ICE when function has no parameters but generics have an `impl Trait` type
CC #3770
From https://github.com/rust-lang/rust-clippy/issues/3770#issuecomment-687565594 (@flip1995):
> Oh I thought I replied to this: I definitely see now that having this
> as a correctness lint might be the wrong categorization. What we might
> want to do is to just allow this lint, if there are comments in the
> arm bodies. But a good first step would be to downgrade this lint to
> style or complexity. I would vote for style since merging two arms is
> not always less complex.
Implement new lint `iter_over_hash_type`
Implements and fixes https://github.com/rust-lang/rust-clippy/issues/11788
This PR adds a new *restriction* lint `iter_over_hash_type` which prevents `Hash`-types (that is, `HashSet` and `HashMap`) from being used as the iterator in `for` loops.
The justification for this is because in `Hash`-based types, the ordering of items is not guaranteed and may vary between executions of the same program on the same hardware. In addition, it reduces readability due to the unclear iteration order.
The implementation of this lint also ensures the following:
- Calls to `HashMap::keys`, `HashMap::values`, and `HashSet::iter` are also denied when used in `for` loops,
- When this expression is used in procedural macros, it is not linted/denied.
changelog: add new `iter_over_hash_type` lint to prevent unordered iterations through hashed data structures
