Handle false positive with `map_clone` lint
### Summary
- Fixes https://github.com/rust-lang/rust-clippy/issues/12271
- (This is my first contribution to clippy and any suggestion would be appreciated)
changelog: [`map_clone`]: Handle false positive with `map_clone` lint
lint when calling the blanket `Into` impl from a `From` impl
Closes#11150
```
warning: function cannot return without recursing
--> x.rs:9:9
|
9 | / fn from(value: f32) -> Self {
10 | | value.into()
11 | | }
| |_________^
|
note: recursive call site
--> x.rs:10:13
|
10 | value.into()
| ^^^^^^^^^^^^
```
I'm also thinking that we can probably generalize this lint to #11032 at some point (instead of hardcoding a bunch of impls), like how rustc's `unconditional_recursion` works, at least up to one indirect call, but this still seems useful for now :)
I've also noticed that we use `fn_def_id` in a bunch of lints and then try to get the node args of the call in a separate step, so I made a helper function that does both in one. I intend to refactor a bunch of uses of `fn_def_id` to use this later
I can add more test cases, but this is already using much of the same logic that exists for the other impls that this lint looks for (e.g. making sure that there are no conditional returns).
changelog: [`unconditional_recursion`]: emit a warning inside of `From::from` when unconditionally calling the blanket `.into()` impl
[`cast_lossless`]: Suggest type alias instead of the aliased type
Fixes#11285
Still an issue with the "from" side, i.e., `I8::from(1) as I64` shows as `i8 to I64`, but this should be ok. Not possible to reliably fix currently anyway.
changelog: [`cast_lossless`]: Suggest type alias instead of the aliased type
chore: fix some typos
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---
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changelog:
Move `iter_nth` to `style`, add machine applicable suggestion
There's no `O(n)` involved with `.iter().nth()` on the linted types since the iterator implementations provide `nth` and/or `advance_by` that operate in `O(1)`
For slice iterators the codegen is equivalent, `VecDeque`'s iterator seems to codegen differently but that doesn't seem significant enough to keep it as a perf lint
changelog: [`iter_nth`] Move to `style`
r? `@flip1995`
Fix typo in section '6.10. Macro Expansions' of the Clippy Book
Under the "Span.ctxt method" heading in *Section 6.10. Macro Expansions* of the *Clippy Book*, the type returned by the
`Span::ctxt` method is listed as `SpanContext`. The correct type name should be `SyntaxContext`.
---
changelog: Fixed typo in "Section 6.10. Macro Expansions" of the Clippy Book. `SpanContext` changed to `SyntaxContext`.
[`manual_retain`]: Fix duplicate diagnostics
Relates to: #12379
The first lint guard executed in `LateLintPass::check_expr` was testing if the parent was of type `ExprKind::Assign`. This meant the lint emitted on both sides of the assignment operator when `check_expr` is called on either `Expr`. The guard in the fix only lints once when the `Expr` is of kind `Assign`.
changelog: Fix duplicate lint diagnostic emission from [`manual_retain`]
Add new `duplicated_attributes` lint
It's a lint idea that `@llogiq` gave me while reviewing another PR.
There are some limitations, in particular for the "output". Initially I wanted to make it possible for directly lint against the whole attribute if its parts were all duplicated, but then I realized that the output would be chaotic if the duplicates were coming from different attributes, so I preferred to go to the simplest way and simply emit a warning for each entry. Not the best, but makes the implementation much easier.
Another limitation is that `cfg_attr` would be a bit more tricky to implement because we need to check if two `cfg` sets are exactly the same. I added a FIXME and will likely come back to it later.
And finally, I updated the `cargo dev update_lints` command because the generated `tests/ui/rename.rs` file was emitting the `duplicated_attributes` lint, so I allowed this lint inside it to prevent it from working.
changelog: Add new `duplicated_attributes` lint
Fix dependency specifications
As Clippy lacks `Cargo.lock`, it makes sense to test its dependency specifications with [direct-minimal-versions](https://doc.rust-lang.org/cargo/reference/unstable.html#direct-minimal-versions). This can be done with the following addition to `.cargo/config.toml`.
```toml
[unstable]
direct-minimal-versions = true
```
* `tempfile` 3.3 is required by `clippy_lints`.
* `regex` 1.5.5 is required by `ui_test` 0.22.2.
* `quote` 1.0.25 is required by `syn` 2.0.0.
* `serde` 1.0.145 is required by `toml` 0.7.3.
changelog: none
[`single_match`]: Fix duplicate diagnostics
Relates to #12379
edit two test file
`tests/ui/single_match_else.rs`
`tests/ui/single_match.rs`
those two test file point to the same lint
---
changelog: [`single_match`] Fix duplicate diagnostics
[`seek_from_current`]: readability improvements
fixes#12457.
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`seek_from_current`]: readability improvements
add documentation to the `span_lint_hir` functions
As far as I could tell, these weren't documented anywhere, and since this is sometimes needed over `span_lint` for `#[allow]` attrs to work, I thought I would add a little bit of documentation.
When I started with clippy development, I also had no idea what these functions were for.
changelog: none
Add new `manual_unwrap_or_default` lint
This adds a new lint checking if a `match` or a `if let` can be replaced with `unwrap_or_default`.
----
changelog: Add new [`manual_unwrap_or_default`] lint
Add new lint `zero_repeat_side_effects`
Fixes https://github.com/rust-lang/rust-clippy/issues/6439
Adds a new `suspicious` lint zero_repeat_side_effects. This lint warns the user when initializing an array or `Vec` using the `Repeat` syntax, i.e., `[x; y]`. If `x` is an `Expr::Call/MethodCall` or contains an `Expr::Call/MethodCall` and `y` is zero, then there is a chance that the internal call can produce side effects, such as printing to console, which is not very obvious.
This lint warns against this and instead suggests to separate out the function call and the array/Vec initialization.
changelog: Add new lint `zero_repeat_side_effects`
use `span_lint_hir` instead of `span_lint` in more lints
Decided to grep for `check_(fn|block)` and look where `span_lint` is used, since some lints lint will then emit a lint on a statement or expression in that function, which would use the wrong lint level attributes
The `LintContext` keeps track of the last entered HIR node that had any attributes, and uses those (and its parents) for figuring out the lint level when a lint is emitted
However, this only works when we actually emit a lint at the same node as the `check_*` function we are in.
If we're in `check_fn` and we emit a lint on a statement within that function, then there is no way to allow the lint only for that one statement (if `span_lint` is used). It would only count allow attributes on the function
changelog: [`needless_return`]: [`useless_let_if_seq`]: [`mut_mut`]: [`read_zero_byte_vec`]: [`unused_io_amount`]: [`unused_peekable`]: now respects `#[allow]` attributes on the affected statement instead of only on the enclosing block or function
[`mut_mut`]: Fix duplicate diags
Relates to #12379
The `mut_mut` lint produced two diagnostics for each `mut mut` pattern in `ty` inside `block`s because `MutVisitor::visit_ty` was called from `MutMut::check_ty` and `MutMut::check_block` independently. This PR fixes the issue.
---
changelog: [`mut_mut`]: Fix duplicate diagnostics
New lint `const_is_empty`
This lint detects calls to `.is_empty()` on an entity initialized from a string literal and flag them as suspicious. To avoid triggering on macros called from generated code, it checks that the `.is_empty()` receiver, the call itself and the initialization come from the same context.
Fixes#12307
changelog: [`const_is_empty`]: new lint
